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Preview: American Journal of Neuroradiology recent issues

American Journal of Neuroradiology recent issues



American Journal of Neuroradiology (AJNR) RSS feed -- recent issue. AJNR (hwmaint.ajnr.org ) is the premier journal for diagnostic and interventional neuroradiology, publishing more than 200 fully reviewed scientific papers, case reports, and technical



 



Carotid Artery Wall Imaging: Perspective and Guidelines from the ASNR Vessel Wall Imaging Study Group and Expert Consensus Recommendations of the American Society of Neuroradiology [EXTRACRANIAL VASCULAR]

2018-02-13T08:00:48-08:00

SUMMARY:

Identification of carotid artery atherosclerosis is conventionally based on measurements of luminal stenosis and surface irregularities using in vivo imaging techniques including sonography, CT and MR angiography, and digital subtraction angiography. However, histopathologic studies demonstrate considerable differences between plaques with identical degrees of stenosis and indicate that certain plaque features are associated with increased risk for ischemic events. The ability to look beyond the lumen using highly developed vessel wall imaging methods to identify plaque vulnerable to disruption has prompted an active debate as to whether a paradigm shift is needed to move away from relying on measurements of luminal stenosis for gauging the risk of ischemic injury. Further evaluation in randomized clinical trials will help to better define the exact role of plaque imaging in clinical decision-making. However, current carotid vessel wall imaging techniques can be informative. The goal of this article is to present the perspective of the ASNR Vessel Wall Imaging Study Group as it relates to the current status of arterial wall imaging in carotid artery disease.







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2018-02-13T08:00:48-08:00










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2018-02-13T08:00:48-08:00




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2018-02-13T08:00:48-08:00




Radiomics in Brain Tumor: Image Assessment, Quantitative Feature Descriptors, and Machine-Learning Approaches [ADULT BRAIN]

2018-02-13T08:00:48-08:00

SUMMARY:

Radiomics describes a broad set of computational methods that extract quantitative features from radiographic images. The resulting features can be used to inform imaging diagnosis, prognosis, and therapy response in oncology. However, major challenges remain for methodologic developments to optimize feature extraction and provide rapid information flow in clinical settings. Equally important, to be clinically useful, predictive radiomic properties must be clearly linked to meaningful biologic characteristics and qualitative imaging properties familiar to radiologists. Here we use a cross-disciplinary approach to highlight studies in radiomics. We review brain tumor radiologic studies (eg, imaging interpretation) through computational models (eg, computer vision and machine learning) that provide novel clinical insights. We outline current quantitative image feature extraction and prediction strategies with different levels of available clinical classes for supporting clinical decision-making. We further discuss machine-learning challenges and data opportunities to advance radiomic studies.




John Nash and the Organization of Stroke Care [research-article]

2018-02-13T08:00:48-08:00

SUMMARY:

The concept of Nash equilibrium, developed by John Forbes Nash Jr, states that an equilibrium in noncooperative games is reached when each player takes the best action for himself or herself, taking into account the actions of the other players. We apply this concept to the provision of endovascular thrombectomy in the treatment of acute ischemic stroke and suggest that collaboration among hospitals in a health care jurisdiction could result in practices such as shared call pools for neurointervention teams, leading to better patient care through streamlined systems.




MR Perfusion to Determine the Status of Collaterals in Patients with Acute Ischemic Stroke: A Look Beyond Time Maps [ADULT BRAIN]

2018-02-13T08:00:48-08:00

BACKGROUND AND PURPOSE:

Patients with acute stroke with robust collateral flow have better clinical outcomes and may benefit from endovascular treatment throughout an extended time window. Using a multiparametric approach, we aimed to identify MR perfusion parameters that can represent the extent of collaterals, approximating DSA.

MATERIALS AND METHODS:

Patients with anterior circulation proximal arterial occlusion who had baseline MR perfusion and DSA were evaluated. The volume of arterial tissue delay (ATD) at thresholds of 2–6 seconds (ATD2–6 seconds) and >6 seconds (ATD>6 seconds) in addition to corresponding values of normalized CBV and CBF was calculated using VOI analysis. The association of MR perfusion parameters and the status of collaterals on DSA were assessed by multivariate analyses. Receiver operating characteristic analysis was performed.

RESULTS:

Of 108 patients reviewed, 39 met our inclusion criteria. On DSA, 22/39 (56%) patients had good collaterals. Patients with good collaterals had significantly smaller baseline and final infarct volumes, smaller volumes of severe hypoperfusion (ATD>6 seconds), larger volumes of moderate hypoperfusion (ATD2–6 seconds), and higher relative CBF and relative CBV values than patients with insufficient collaterals. Combining the 2 parameters into a Perfusion Collateral Index (volume of ATD2–6 seconds x relative CBV2–6 seconds) yielded the highest accuracy for predicting collateral status: At a threshold of 61.7, this index identified 15/17 (88%) patients with insufficient collaterals and 22/22 (100%) patients with good collaterals, for an overall accuracy of 94.1%.

CONCLUSIONS:

The Perfusion Collateral Index can predict the baseline collateral status with 94% diagnostic accuracy compared with DSA.




On the Reproducibility of Inversion Recovery Intravoxel Incoherent Motion Imaging in Cerebrovascular Disease [ADULT BRAIN]

2018-02-13T08:00:48-08:00

BACKGROUND AND PURPOSE:

Intravoxel incoherent motion imaging can measure both microvascular and parenchymal abnormalities simultaneously. The contamination of CSF signal can be suppressed using inversion recovery preparation. The clinical feasibility of inversion recovery–intravoxel incoherent motion imaging was investigated in patients with cerebrovascular disease by studying its reproducibility.

MATERIALS AND METHODS:

Sixteen patients with cerebrovascular disease (66 ± 8 years of age) underwent inversion recovery–intravoxel incoherent motion imaging twice. The reproducibility of the perfusion volume fraction and parenchymal diffusivity was calculated with the coefficient of variation, intraclass correlation coefficient, and the repeatability coefficient. ROIs included the normal-appearing white matter, cortex, deep gray matter, white matter hyperintensities, and vascular lesions.

RESULTS:

Values for the perfusion volume fraction ranged from 2.42 to 3.97 x10–2 and for parenchymal diffusivity from 7.20 to 9.11 x 10–4 mm2/s, with higher values found in the white matter hyperintensities and vascular lesions. Coefficients of variation were <3.70% in normal-appearing tissue and <9.15% for lesions. Intraclass correlation coefficients were good to excellent, showing values ranging from 0.82 to 0.99 in all ROIs, except the deep gray matter and cortex, with intraclass correlation coefficients of 0.66 and 0.54, respectively. The repeatability coefficients ranged from 0.15 to 0.96 x 10–2 and 0.10 to 0.37 x 10–4 mm2/s for perfusion volume fraction and parenchymal diffusivity, respectively.

CONCLUSIONS:

Good reproducibility of inversion recovery–intravoxel incoherent motion imaging was observed with low coefficients of variation and high intraclass correlation coefficients in normal-appearing tissue and lesion areas in cerebrovascular disease. Good reproducibility of inversion recovery–intravoxel incoherent motion imaging in cerebrovascular disease is feasible in monitoring disease progression or treatment responses in the clinic.




The CT Swirl Sign Is Associated with Hematoma Expansion in Intracerebral Hemorrhage [ADULT BRAIN]

2018-02-13T08:00:48-08:00

BACKGROUND AND PURPOSE:

Hematoma expansion is an independent determinant of poor clinical outcome in intracerebral hemorrhage. Although the "spot sign" predicts hematoma expansion, the identification requires CT angiography, which limits its general accessibility in some hospital settings. Noncontrast CT, without the need for CT angiography, may identify sites of active extravasation, termed the "swirl sign." We aimed to determine the association of the swirl sign with hematoma expansion.

MATERIALS AND METHODS:

Patients with spontaneous intracerebral hemorrhage between 2007 and 2014 who underwent an initial and subsequent noncontrast CT at a single center were retrospectively identified. The swirl sign, on noncontrast CT, was defined as iso- or hypodensity within a hyperdense region that extended across 2 contiguous 5-mm axial CT sections.

RESULTS:

A total of 212 patients met the inclusion criteria. The swirl sign was identified in 91 patients with excellent interobserver agreement ( = 0.87). The swirl sign was associated with larger initial hematoma (P < .001) and earlier initial CT (P < .001) and hematoma expansion (P = .028). Multivariable regression modeling demonstrated that if one assumed similar initial hematoma volume, onset-to-first scan, and time between CT scans, the median absolute hematoma growth was 5.77 mL (95% CI, 2.37–9.18 mL; P = .001) and relative growth was 35.6% (95% CI, 18.5%–52.6%; P < .001) higher in patients with the swirl sign compared with those without.

CONCLUSIONS:

The NCCT swirl sign was reliably identified and is associated with hematoma expansion. We propose that the swirl sign be included in risk stratification of intracerebral hemorrhage and considered for inclusion in clinical trials.




Dural Arteriovenous Fistulas: A Characteristic Pattern of Edema and Enhancement of the Medulla on MRI [ADULT BRAIN]

2018-02-13T08:00:48-08:00

SUMMARY:

Medullary edema with enhancement is rarely reported at initial MR imaging in intracranial dural arteriovenous fistulas. We report a series of 5 patients with dural arteriovenous fistulas, all of whom demonstrated a characteristic pattern of central medullary edema and medullary enhancement at initial MR imaging. Cognard type V dural arteriovenous fistula, defined by drainage into the perimedullary veins and the veins surrounding the brain stem, is a rare yet well-described pathologic entity. Even more rarely reported, however, is its clinical presentation with predominantly bulbar symptoms and MR imaging findings of central medullary edema with enhancement. This constellation of findings frequently leads to a convoluted clinical picture, prompting work-up for alternative disease processes and delaying diagnosis. Because an expedited diagnosis is critical in preventing poor outcomes, it is paramount to make the referring physician and neuroradiologist more cognizant of this rare-yet-characteristic imaging manifestation of dural arteriovenous fistula.




White Matter Changes Related to Subconcussive Impact Frequency during a Single Season of High School Football [ADULT BRAIN]

2018-02-13T08:00:48-08:00

BACKGROUND AND PURPOSE:

The effect of exposing the developing brain of a high school football player to subconcussive impacts during a single season is unknown. The purpose of this pilot study was to use diffusion tensor imaging to assess white matter changes during a single high school football season, and to correlate these changes with impacts measured by helmet accelerometer data and neurocognitive test scores collected during the same period.

MATERIALS AND METHODS:

Seventeen male athletes (mean age, 16 ± 0.73 years) underwent MR imaging before and after the season. Changes in fractional anisotropy across the white matter skeleton were assessed with Tract-Based Spatial Statistics and ROI analysis.

RESULTS:

The mean number of impacts over a 10-g threshold sustained was 414 ± 291. Voxelwise analysis failed to show significant changes in fractional anisotropy across the season or a correlation with impact frequency, after correcting for multiple comparisons. ROI analysis showed significant (P < .05, corrected) decreases in fractional anisotropy in the fornix-stria terminalis and cingulum hippocampus, which were related to impact frequency. The effects were strongest in the fornix-stria terminalis, where decreases in fractional anisotropy correlated with worsening visual memory.

CONCLUSIONS:

Our findings suggest that subclinical neurotrauma related to participation in American football may result in white matter injury and that alterations in white matter tracts within the limbic system may be detectable after only 1 season of play at the high school level.




MR Imaging Characteristics Associate with Tumor-Associated Macrophages in Glioblastoma and Provide an Improved Signature for Survival Prognostication [ADULT BRAIN]

2018-02-13T08:00:48-08:00

BACKGROUND AND PURPOSE:

In glioblastoma, tumor-associated macrophages have tumor-promoting properties. This study determined whether routine MR imaging features could predict molecular subtypes of glioblastoma that differ in the content of tumor-associated macrophages.

MATERIALS AND METHODS:

Seven internally derived MR imaging features were assessed in 180 patients, and 25 features from the Visually AcceSAble Rembrandt Images feature set were assessed in 164 patients. Glioblastomas were divided into subtypes based on the telomere maintenance mechanism: alternative lengthening of telomeres positive (ALT+) and negative (ALT–) and the content of tumor-associated macrophages (with [M+] or without [M–] a high content of macrophages). The 3 most frequent subtypes (ALT+/M–, ALT–/M+, and ALT–/M–) were correlated with MR imaging features and clinical parameters. The fourth group (ALT+/M+) did not have enough cases for correlation with MR imaging features.

RESULTS:

Tumors with a regular margin and those lacking a fungating margin, an expansive T1/FLAIR ratio, and reduced ependymal extension were more frequent in the subgroup of ALT+/M– (P < .05). Radiologic necrosis, lack of cystic component (by both criteria), and extensive peritumoral edema were more frequent in ALT–/M+ tumors (P < .05). Multivariate testing with a Cox regression analysis found the cystic imaging feature was additive to tumor subtype, and O6-methylguanine methyltransferase (MGMT) status to predict improved patient survival (P < .05).

CONCLUSIONS:

Glioblastomas with tumor-associated macrophages are associated with routine MR imaging features consistent with these tumors being more aggressive. Inclusion of cystic change with molecular subtypes and MGMT status provided a better estimate of survival.




Diagnostic Accuracy of Centrally Restricted Diffusion in the Differentiation of Treatment-Related Necrosis from Tumor Recurrence in High-Grade Gliomas [ADULT BRAIN]

2018-02-13T08:00:48-08:00

BACKGROUND AND PURPOSE:

Centrally restricted diffusion has been demonstrated in recurrent high-grade gliomas treated with bevacizumab. Our purpose was to assess the accuracy of centrally restricted diffusion in the diagnosis of radiation necrosis in high-grade gliomas not treated with bevacizumab.

MATERIALS AND METHODS:

In this prospective study, we enrolled patients with high-grade gliomas who developed a new ring-enhancing necrotic lesion and who underwent re-resection. The presence of a centrally restricted diffusion within the ring-enhancing lesion was assessed visually on diffusion trace images and by ADC measurements on 3T preoperative diffusion tensor examination. The percentage of tumor recurrence and radiation necrosis in each surgical specimen was defined histopathologically. The association between centrally restricted diffusion and radiation necrosis was assessed using the Fisher exact test. Differences in ADC and the ADC ratio between the groups were assessed via the Mann-Whitney U test, and receiver operating characteristic curve analysis was performed.

RESULTS:

Seventeen patients had re-resected ring-enhancing lesions: 8 cases of radiation necrosis and 9 cases of tumor recurrence. There was significant association between centrally restricted diffusion by visual assessment and radiation necrosis (P = .015) with a sensitivity of 75% and a specificity of 88.9%, a positive predictive value 85.7%, and a negative predictive value of 80% for the diagnosis of radiation necrosis. There was a statistically significant difference in the ADC and ADC ratio between radiation necrosis and tumor recurrence (P = .027).

CONCLUSIONS:

The presence of centrally restricted diffusion in a new ring-enhancing lesion might indicate radiation necrosis rather than tumor recurrence in high-grade gliomas previously treated with standard chemoradiation without bevacizumab.




Addition of Amide Proton Transfer Imaging to FDG-PET/CT Improves Diagnostic Accuracy in Glioma Grading: A Preliminary Study Using the Continuous Net Reclassification Analysis [ADULT BRAIN]

2018-02-13T08:00:48-08:00

BACKGROUND AND PURPOSE:

Amide proton transfer imaging has been successfully applied to brain tumors, however, the relationships between amide proton transfer and other quantitative imaging values have yet to be investigated. The aim was to examine the additive value of amide proton transfer imaging alongside [18F] FDG-PET and DWI for preoperative grading of gliomas.

MATERIALS AND METHODS:

Forty-nine patients with newly diagnosed gliomas were included in this retrospective study. All patients had undergone MR imaging, including DWI and amide proton transfer imaging on 3T scanners, and [18F] FDG-PET. Logistic regression analyses were conducted to examine the relationship between each imaging parameter and the presence of high-grade (grade III and/or IV) glioma. These parameters included the tumor-to-normal ratio of FDG uptake, minimum ADC, mean amide proton transfer value, and their combinations. In each model, the overall discriminative power for the detection of high-grade glioma was assessed with receiver operating characteristic curve analysis. Additive information from minimum ADC and mean amide proton transfer was also evaluated by continuous net reclassification improvement. P < .05 was considered significant.

RESULTS:

Tumor-to-normal ratio, minimum ADC, and mean amide proton transfer demonstrated comparable diagnostic accuracy in differentiating high-grade from low-grade gliomas. When mean amide proton transfer was combined with the tumor-to-normal ratio, the continuous net reclassification improvement was 0.64 (95% CI, 0.036–1.24; P = .04) for diagnosing high-grade glioma and 0.95 (95% CI, 0.39–1.52; P = .001) for diagnosing glioblastoma. When minimum ADC was combined with the tumor-to-normal ratio, the continuous net reclassification improvement was 0.43 (95% CI, –0.17–1.04; P = .16) for diagnosing high-grade glioma, and 1.36 (95% CI, 0.79–1.92; P < .001) for diagnosing glioblastoma.

CONCLUSIONS:

Addition of amide proton transfer imaging to FDG-PET/CT may improve the ability to differentiate high-grade from low-grade gliomas.




Diffusion-Weighted Imaging of Brain Metastasis from Lung Cancer: Correlation of MRI Parameters with the Histologic Type and Gene Mutation Status [ADULT BRAIN]

2018-02-13T08:00:48-08:00

BACKGROUND AND PURPOSE:

Development of noninvasive imaging biomarkers indicating the histology and the gene mutation status of brain metastasis from lung cancer is important. We aimed to investigate diffusion-weighted imaging parameters as predictors of the histology and gene mutations of brain metastasis from lung cancer.

MATERIALS AND METHODS:

DWI data for 74 patients with brain metastasis from lung cancer were retrospectively reviewed. The patients were first grouped according to the primary tumor histology (adenocarcinoma, small-cell lung cancer, squamous cell carcinoma), and those with adenocarcinoma were further divided into epidermal growth factor receptor (EFGR) mutation–positive and wild type groups. Sex; age; number, size, and location of brain metastasis; DWI visual scores; the minimum ADC; and the normalized ADC ratio were compared among groups using 2 and ANOVA. Multiple logistic regression analysis was performed to determine independent predictors of the EGFR mutation.

RESULTS:

The minimum ADC was lower in the small-cell lung cancer group than in the other 2 groups, though the difference was not significant. Furthermore, minimum ADC and the normalized ADC ratio were significantly lower in the EGFR mutation–positive group than in the wild type group (P = .021 and .014, respectively). Multivariate analysis revealed that minimum ADC and the normalized ADC ratio were independently associated with the EGFR mutation status (P = .028 and .021, respectively).

CONCLUSIONS:

Our results suggest that DWI parameters (minimum ADC and normalized ADC ratio) for the solid components of brain metastasis from lung cancer are not correlated with their histology, whereas they can predict the EGFR mutation status in brain metastasis from lung adenocarcinoma.




Diagnostic Accuracy of Amino Acid and FDG-PET in Differentiating Brain Metastasis Recurrence from Radionecrosis after Radiotherapy: A Systematic Review and Meta-Analysis [ADULT BRAIN]

2018-02-13T08:00:48-08:00

BACKGROUND:

Current studies that analyze the usefulness of amino acid and FDG-PET in distinguishing brain metastasis recurrence and radionecrosis after radiation therapy are limited by small cohort size.

PURPOSE:

Our aim was to assess the diagnostic accuracy of amino acid and FDG-PET in differentiating brain metastasis recurrence from radionecrosis after radiation therapy.

DATA SOURCES:

Studies were retrieved from PubMed, Embase, and the Cochrane Library.

STUDY SELECTION:

Fifteen studies were included from the literature. Each study used PET to differentiate radiation necrosis from tumor recurrence in contrast-enhancing lesions on follow-up brain MR imaging after treating brain metastasis with radiation therapy.

DATA ANALYSIS:

Data were analyzed with a bivariate random-effects model. Sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were pooled, and a summary receiver operating characteristic curve was fit to the data.

DATA SYNTHESIS:

The overall pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio of PET were 0.85, 0.88, 7.0, 0.17, and 40, respectively. The area under the receiver operating characteristic curve was 0.93. On subgroup analysis of different tracers, amino acid and FDG-PET had similar diagnostic accuracy. Meta-regression analysis demonstrated that the method of quantification based on patient, lesion, or PET scan (based on lesion versus not, P = .07) contributed to the heterogeneity.

LIMITATIONS:

Our study was limited by small sample size, and 60% of the included studies were of retrospective design.

CONCLUSIONS:

Amino acid and FDG-PET had good diagnostic accuracy in differentiating brain metastasis recurrence from radionecrosis after radiation therapy.




Feasibility of Brain Atrophy Measurement in Clinical Routine without Prior Standardization of the MRI Protocol: Results from MS-MRIUS, a Longitudinal Observational, Multicenter Real-World Outcome Study in Patients with Relapsing-Remitting MS [ADULT BRAIN]

2018-02-13T08:00:48-08:00

BACKGROUND AND PURPOSE:

Feasibility of brain atrophy measurement in patients with MS in clinical routine, without prior standardization of the MRI protocol, is unknown. Our aim was to investigate the feasibility of brain atrophy measurement in patients with MS in clinical routine.

MATERIALS AND METHODS:

Multiple Sclerosis and Clinical Outcome and MR Imaging in the United States (MS-MRIUS) is a multicenter (33 sites), retrospective study that included patients with relapsing-remitting MS who began treatment with fingolimod. Brain MR imaging examinations previously acquired at the baseline and follow-up periods on 1.5T or 3T scanners with no prior standardization were used, to resemble a real-world situation. Brain atrophy outcomes included the percentage brain volume change measured by structural image evaluation with normalization of atrophy on 2D-T1-weighted imaging and 3D-T1WI and the percentage lateral ventricle volume change, measured by VIENA on 2D-T1WI and 3D-T1WI and NeuroSTREAM on T2-fluid-attenuated inversion recovery examinations.

RESULTS:

A total of 590 patients, followed for 16 months, were included. There were 585 (99.2%) T2-FLAIR, 425 (72%) 2D-T1WI, and 166 (28.2%) 3D-T1WI longitudinal pairs of examinations available. Excluding MR imaging examinations with scanner changes, the analyses were available on 388 (65.8%) patients on T2-FLAIR for the percentage lateral ventricle volume change, 259 and 257 (43.9% and 43.6%, respectively) on 2D-T1WI for the percentage brain volume change and the percentage lateral ventricle volume change, and 110 (18.6%) on 3D-T1WI for the percentage brain volume change and percentage lateral ventricle volume change. The median annualized percentage brain volume change was –0.31% on 2D-T1WI and –0.38% on 3D-T1WI. The median annualized percentage lateral ventricle volume change was 0.95% on 2D-T1WI, 1.47% on 3D-T1WI, and 0.90% on T2-FLAIR.

CONCLUSIONS:

Brain atrophy was more readily assessed by estimating the percentage lateral ventricle volume change on T2-FLAIR compared with the percentage brain volume change or percentage lateral ventricle volume change using 2D- or 3D-T1WI in this observational retrospective study. Although measurement of the percentage brain volume change on 3D-T1WI remains the criterion standard and should be encouraged in future prospective studies, T2-FLAIR–derived percentage lateral ventricle volume change may be a more feasible surrogate when historical or other practical constraints limit the availability of percentage brain volume change on 3D-T1WI.




Improved Precision of Automatic Brain Volume Measurements in Patients with Clinically Isolated Syndrome and Multiple Sclerosis Using Edema Correction [ADULT BRAIN]

2018-02-13T08:00:48-08:00

BACKGROUND AND PURPOSE:

The presence of edema will result in increased brain volume, which may obscure progressing brain atrophy. Similarly, treatment-induced edema reduction may appear as accelerated brain tissue loss (pseudoatrophy). The purpose of this study was to correlate brain tissue properties to brain volume, to investigate the possibilities for edema correction and the resulting improvement of the precision of automated brain volume measurements.

MATERIALS AND METHODS:

A group of 38 patients with clinically isolated syndrome or newly diagnosed MS were imaged at inclusion and after 1, 2, and 4 years using an MR quantification sequence. Brain volume, relaxation rates (R1 and R2), and proton density were measured by automated software.

RESULTS:

The reduction of normalized brain volume with time after inclusion was 0.273%/year. The mean SDs were 0.508%, 0.526%, 0.454%, and 0.687% at baseline and 1, 2, and 4 years. Linear regression of the relative change of normalized brain volume and the relative change of R1, R2, and proton density showed slopes of –0.198 (P < .001), 0.156 (P = .04), and 0.488 (P < .001), respectively. After we applied the measured proton density as a correction factor, the mean SDs decreased to 24.2%, 4.8%, 33.3%, and 17.4%, respectively. The observed atrophy rate reduced from 0.273%/year to 0.238%/year.

CONCLUSIONS:

Correlations between volume and R1, R2, and proton density were observed in the brain, suggesting that a change of brain tissue properties can affect brain volume. Correction using these parameters decreased the variation of brain volume measurements and may have reduced the effect of pseudoatrophy.




Combining Quantitative Susceptibility Mapping with Automatic Zero Reference (QSM0) and Myelin Water Fraction Imaging to Quantify Iron-Related Myelin Damage in Chronic Active MS Lesions [ADULT BRAIN]

2018-02-13T08:00:48-08:00

BACKGROUND AND PURPOSE:

A hyperintense rim on susceptibility in chronic MS lesions is consistent with iron deposition, and the purpose of this study was to quantify iron-related myelin damage within these lesions as compared with those without rim.

MATERIALS AND METHODS:

Forty-six patients had 2 longitudinal quantitative susceptibility mapping with automatic zero reference scans with a mean interval of 28.9 ± 11.4 months. Myelin water fraction mapping by using fast acquisition with spiral trajectory and T2 prep was obtained at the second time point to measure myelin damage. Mixed-effects models were used to assess lesion quantitative susceptibility mapping and myelin water fraction values.

RESULTS:

Quantitative susceptibility mapping scans were on average 6.8 parts per billion higher in 116 rim-positive lesions compared with 441 rim-negative lesions (P < .001). All rim-positive lesions retained a hyperintense rim over time, with increasing quantitative susceptibility mapping values of both the rim and core regions (P < .001). Quantitative susceptibility mapping scans and myelin water fraction in rim-positive lesions decreased from rim to core, which is consistent with rim iron deposition. Whole lesion myelin water fractions for rim-positive and rim-negative lesions were 0.055 ± 0.07 and 0.066 ± 0.04, respectively. In the mixed-effects model, rim-positive lesions had on average 0.01 lower myelin water fraction compared with rim-negative lesions (P < .001). The volume of the rim at the initial quantitative susceptibility mapping scan was negatively associated with follow-up myelin water fraction (P < .01).

CONCLUSIONS:

Quantitative susceptibility mapping rim-positive lesions maintained a hyperintense rim, increased in susceptibility, and had more myelin damage compared with rim-negative lesions. Our results are consistent with the identification of chronic active MS lesions and may provide a target for therapeutic interventions to reduce myelin damage.




Noninvasive Assessment of Intracranial Pressure Status in Idiopathic Intracranial Hypertension Using Displacement Encoding with Stimulated Echoes (DENSE) MRI: A Prospective Patient Study with Contemporaneous CSF Pressure Correlation [ADULT BRAIN]

2018-02-13T08:00:48-08:00

BACKGROUND AND PURPOSE:

Intracranial pressure is estimated invasively by using lumbar puncture with CSF opening pressure measurement. This study evaluated displacement encoding with stimulated echoes (DENSE), an MR imaging technique highly sensitive to brain motion, as a noninvasive means of assessing intracranial pressure status.

MATERIALS AND METHODS:

Nine patients with suspected elevated intracranial pressure and 9 healthy control subjects were included in this prospective study. Controls underwent DENSE MR imaging through the midsagittal brain. Patients underwent DENSE MR imaging followed immediately by lumbar puncture with opening pressure measurement, CSF removal, closing pressure measurement, and immediate repeat DENSE MR imaging. Phase-reconstructed images were processed producing displacement maps, and pontine displacement was calculated. Patient data were analyzed to determine the effects of measured pressure on pontine displacement. Patient and control data were analyzed to assess the effects of clinical status (pre–lumbar puncture, post–lumbar puncture, or control) on pontine displacement.

RESULTS:

Patients demonstrated imaging findings suggesting chronically elevated intracranial pressure, whereas healthy control volunteers demonstrated no imaging abnormalities. All patients had elevated opening pressure (median, 36.0 cm water), decreased by the removal of CSF to a median closing pressure of 17.0 cm water. Patients pre–lumbar puncture had significantly smaller pontine displacement than they did post–lumbar puncture after CSF pressure reduction (P = .001) and compared with controls (P = .01). Post–lumbar puncture patients had statistically similar pontine displacements to controls. Measured CSF pressure in patients pre– and post–lumbar puncture correlated significantly with pontine displacement (r = 0.49; P = .04).

CONCLUSIONS:

This study establishes a relationship between pontine displacement from DENSE MR imaging and measured pressure obtained contemporaneously by lumbar puncture, providing a method to noninvasively assess intracranial pressure status in idiopathic intracranial hypertension.




Leukoaraiosis Attenuates Diagnostic Accuracy of Large-Vessel Occlusion Scales [INTERVENTIONAL]

2018-02-13T08:00:48-08:00

BACKGROUND AND PURPOSE:

Prehospital stroke scales may help identify patients likely to have large-vessel occlusion to facilitate rapid triage to thrombectomy-capable stroke centers. Scale misclassification may result in inaccurate decisions and possible harm. Pre-existing leukoaraiosis has been shown to attenuate the association between deficit type and stroke severity. We sought to determine whether leukoaraiosis affects the predictive ability of 5 commonly used large-vessel occlusion scales.

MATERIALS AND METHODS:

We retrospectively analyzed 274 consecutive patients with stroke with available brain MR imaging and vessel imaging. We used the following large-vessel occlusion scales: the 3-Item Stroke Scale; Field Assessment Stroke Triage for Emergency Destination; Rapid Arterial Occlusion Evaluation; Vision, Aphasia, Neglect score; and Cincinnati Prehospital Stroke Severity Scale. For diagnostic scale accuracy, we assessed sensitivity, specificity, positive predictive value, negative predictive value, and . Multivariable logistic regression was used to determine the predictive ability of the scales after adjustment for leukoaraiosis and potential confounders.

RESULTS:

In unadjusted analyses, all scales predicted the presence of large-vessel occlusion (n = 46, P < .01 each), though diagnostic accuracy was attenuated among patients with moderate-to-severe leukoaraiosis. After adjustment, the Field Assessment Stroke Triage for Emergency Destination (OR = 3.2; 95% CI, 1.1–9.5; P = .033) and Rapid Arterial Occlusion Evaluation (OR = 3.7; 95% CI, 1.3–10.8; P = .015), but not the 3-Item Stroke Scale (OR = 5.4; 95% CI, 0.86–33.9; P = .073), Vision, Aphasia, Neglect score (OR = 2.5; 95% CI, 0.8–7.2), and Cincinnati Prehospital Stroke Severity Scale (OR = 2.8; 95% CI, 1.0–8.0), predicted large-vessel occlusion.

CONCLUSIONS:

The diagnostic accuracy of the tested large-vessel occlusion scales was attenuated in the presence of moderate-to-severe leukoaraiosis. This information that may aid the design of future studies that require large-vessel occlusion scale screening of patients who are likely to have concomitant leukoaraiosis.




The Role of Hemodynamics in Intracranial Bifurcation Arteries after Aneurysm Treatment with Flow-Diverter Stents [INTERVENTIONAL]

2018-02-13T08:00:48-08:00

BACKGROUND AND PURPOSE:

Treatment of intracranial bifurcation aneurysms with flow-diverter stents can lead to caliber changes of the distal vessels in a subacute phase. This study aims to evaluate whether local anatomy and flow disruption induced by flow-diverter stents are associated with vessel caliber changes in intracranial bifurcations.

MATERIALS AND METHODS:

Radiologic images and demographic data were acquired for 25 patients with bifurcation aneurysms treated with flow-diverter stents. Whisker plots and Mann-Whitney rank sum tests were used to evaluate if anatomic data and caliber changes could be linked. Symmetry/asymmetry were defined as diameter ratio 1 = symmetric and diameter ratio <1 = asymmetric. Computational fluid dynamics was performed on idealized and patient-specific anatomies to evaluate flow changes induced by flow-diverter stents in the jailed vessel.

RESULTS:

Statistical analysis identified a marked correspondence between asymmetric bifurcation and caliber change. Symmetry ratios were lower for cases showing narrowing or subacute occlusion (medium daughter vessel diameter ratio = 0.59) compared with cases with posttreatment caliber conservation (medium daughter vessel diameter ratio = 0.95). Computational fluid dynamics analysis in idealized and patient-specific anatomies showed that wall shear stress in the jailed vessel was more affected when flow-diverter stents were deployed in asymmetric bifurcations (diameter ratio <0.65) and less affected when deployed in symmetric anatomies (diameter ratio ~1.00).

CONCLUSIONS:

Anatomic data analysis showed statistically significant correspondence between caliber changes and bifurcation asymmetry characterized by diameter ratio <0.7 (P < .001). Similarly, computational fluid dynamics results showed the highest impact on hemodynamics when flow-diverter stents are deployed in asymmetric bifurcations (diameter ratio <0.65) with noticeable changes on wall sheer stress fields. Further research and clinical validation are necessary to identify all elements involved in vessel caliber changes after flow-diverter stent procedures.




Feasibility of Permanent Stenting with Solitaire FR as a Rescue Treatment for the Reperfusion of Acute Intracranial Artery Occlusion [INTERVENTIONAL]

2018-02-13T08:00:48-08:00

BACKGROUND AND PURPOSE:

The Solitaire FR can be used not only as a tool for mechanical thrombectomy but also as a detachable permanent stent. Our aim was to assess the feasibility and safety of permanent stent placement with the Solitaire FR compared with other self-expanding stents for intracranial artery recanalization for acute ischemic stroke.

MATERIALS AND METHODS:

From January 2011 through January 2016, we retrospectively selected 2979 patients with acute ischemic stroke. Among them, 27 patients who underwent permanent stent placement (13 patients with the Solitaire FR [Solitaire group] and 14 patients with other self-expanding stents [other stent group]) were enrolled. The postprocedural modified TICI grade and angiographic and clinical outcomes were assessed. The safety and efficacy of permanent stent placement of the Solitaire FR for acute large-artery occlusion were evaluated.

RESULTS:

Stent placement was successful in all cases. Modified TICI 2b–3 reperfusion was noted in 84.6% of the Solitaire group and in 78.6% of the other stent group. Procedural time was significantly shorter in the Solitaire group than in the other stent group (P = .022). Shorter procedural time was correlated with favorable outcome ( = 0.46, P = .035). No significant differences were found in the modified TICI grade, NIHSS score, mRS, and hemorrhagic transformation rate between the 2 groups. The acute in-stent thrombosis rate at discharge was significantly lower when a glycoprotein IIb/IIIa inhibitor was injected during the procedure (P = .013).

CONCLUSIONS:

Permanent stent placement with the Solitaire FR compared with other self-expanding stents appears to be feasible and safe as a rescue tool for refractory intra-arterial therapy.




Better Than Nothing: A Rational Approach for Minimizing the Impact of Outflow Strategy on Cerebrovascular Simulations [INTERVENTIONAL]

2018-02-13T08:00:48-08:00

BACKGROUND AND PURPOSE:

Computational fluid dynamics simulations of neurovascular diseases are impacted by various modeling assumptions and uncertainties, including outlet boundary conditions. Many studies of intracranial aneurysms, for example, assume zero pressure at all outlets, often the default ("do-nothing") strategy, with no physiological basis. Others divide outflow according to the outlet diameters cubed, nominally based on the more physiological Murray's law but still susceptible to subjective choices about the segmented model extent. Here we demonstrate the limitations and impact of these outflow strategies, against a novel "splitting" method introduced here.

MATERIALS AND METHODS:

With our method, the segmented lumen is split into its constituent bifurcations, where flow divisions are estimated locally using a power law. Together these provide the global outflow rate boundary conditions. The impact of outflow strategy on flow rates was tested for 70 cases of MCA aneurysm with 0D simulations. The impact on hemodynamic indices used for rupture status assessment was tested for 10 cases with 3D simulations.

RESULTS:

Differences in flow rates among the various strategies were up to 70%, with a non-negligible impact on average and oscillatory wall shear stresses in some cases. Murray-law and splitting methods gave flow rates closest to physiological values reported in the literature; however, only the splitting method was insensitive to arbitrary truncation of the model extent.

CONCLUSIONS:

Cerebrovascular simulations can depend strongly on the outflow strategy. The default zero-pressure method should be avoided in favor of Murray-law or splitting methods, the latter being released as an open-source tool to encourage the standardization of outflow strategies.




Intranasal Esthesioneuroblastoma: CT Patterns Aid in Preventing Routine Nasal Polypectomy [HEAD & NECK]

2018-02-13T08:00:48-08:00

BACKGROUND AND PURPOSE:

Esthesioneuroblastoma is a neuroectodermal tumor that commonly arises in the nasal cavity olfactory recess and, when isolated to the intranasal cavity, can be indistinguishable from benign processes. Because lesional aggressiveness requires a more invasive operation for resection than polypectomy, patients with isolated intranasal lesions were studied to define distinguishing CT characteristics.

MATERIALS AND METHODS:

Patients with intranasal esthesioneuroblastoma and controls without esthesioneuroblastoma with olfactory recess involvement were identified by using a report search tool. Studies demonstrating skull base invasion and/or intracranial extension were excluded. The imaging spectrum of these lesions was reviewed on both CT and MR imaging, and CT findings were compared with those of controls without esthesioneuroblastoma. Two blinded readers assessed subjects with esthesioneuroblastomas and controls without esthesioneuroblastoma and, using only CT criteria, rated their level of suspicion for esthesioneuroblastoma in each case.

RESULTS:

Eight histologically proved cases of intranasal esthesioneuroblastoma were reviewed. All cases had CT demonstrating 3 main findings: 1) an intranasal polypoid lesion with its epicenter in a unilateral olfactory recess, 2) causing asymmetric olfactory recess widening, and 3) extending to the cribriform plate. Twelve patients with non-esthesioneuroblastoma diseases involving the olfactory recess were used as controls. Using these 3 esthesioneuroblastoma CT criteria, 2 blinded readers evaluating patients with esthesioneuroblastoma and controls had good diagnostic accuracy (area under the curve = 0.85 for reader one, 0.81 for reader 2) for predicting esthesioneuroblastoma.

CONCLUSIONS:

Esthesioneuroblastoma can present as a well-marginated intranasal lesion that unilaterally widens the olfactory recess. CT patterns can help predict esthesioneuroblastoma, potentially preventing multiple operations by instigating the correct initial operative management.




Lymphographic-Like Technique for the Treatment of Microcystic Lymphatic Malformation Components of <3 mm [HEAD & NECK]

2018-02-13T08:00:48-08:00

BACKGROUND AND PURPOSE:

The treatment of microcystic lymphatic malformations remains challenging. Our aim was to describe the lymphographic-like technique, a new technique of slow bleomycin infusion for the treatment of microcyst components of <3 mm, performed at our institution.

MATERIALS AND METHODS:

A retrospective analysis of a prospectively collected lymphatic malformation data base was performed. Patients with at least 1 microcystic lymphatic malformation component demonstrated on MR imaging treated by lymphographic-like technique bleomycin infusion were included in the study. Patient interviews and MR imaging were performed to assess subjective and objective (microcystic lymphatic malformation size decrease of >30%) clinical improvement, respectively. Patients were reviewed 3 months after each sclerotherapy session. Lymphographic-like technique safety and efficacy were assessed.

RESULTS:

Between January 2012 and July 2016, sixteen patients (5 males, 11 females; mean age, 15 years; range, 1–47 years) underwent the bleomycin lymphographic-like technique for microcystic lymphatic malformations. Sixty sclerotherapy sessions were performed, with a mean of 4 sessions per patient (range, 1–8 sessions) and a mean follow-up of 26 months (range, 5–58 months). We observed no major and 3 minor complications: 1 eyelid infection, 1 case of severe postprocedural nausea and vomiting, and 1 case of skin discoloration. One patient was lost to follow-up. Overall MR imaging objective improvement was observed in 5/16 (31%) patients; overall improvement of clinical symptoms was obtained in 93% of treated patients.

CONCLUSIONS:

The bleomycin lymphographic-like technique for microcystic lymphatic malformations is safe and feasible with objective improvement in about one-third of patients. MR signal intensity changes after the lymphographic-like technique are associated with subjective improvement of the patient's symptoms.




Semiautomated Middle Ear Volume Measurement as a Predictor of Postsurgical Outcomes for Congenital Aural Atresia [HEAD & NECK]

2018-02-13T08:00:48-08:00

BACKGROUND AND PURPOSE:

Middle ear space is one of the most important components of the Jahrsdoerfer grading system (J-score), which is used to determine surgical candidacy for congenital aural atresia. The purpose of this study was to introduce a semiautomated method for measuring middle ear volume and determine whether middle ear volume, either alone or in combination with the J-score, can be used to predict early postoperative audiometric outcomes.

MATERIALS AND METHODS:

A retrospective analysis was conducted of 18 patients who underwent an operation for unilateral congenital aural atresia at our institution. Using the Livewire Segmentation tool in the Carestream Vue PACS, we segmented middle ear volumes using a semiautomated method for all atretic and contralateral normal ears on preoperative high-resolution CT imaging. Postsurgical audiometric outcome data were then analyzed in the context of these middle ear volumes.

RESULTS:

Atretic middle ear volumes were significantly smaller than those in contralateral normal ears (P < .001). Patients with atretic middle ear volumes of >305 mm3 had significantly better postoperative pure tone average and speech reception thresholds than those with atretic ears below this threshold volume (P = .01 and P = .006, respectively). Atretic middle ear volume incorporated into the J-score offered the best association with normal postoperative hearing (speech reception threshold ≤ 30 dB; OR = 37.8, P = .01).

CONCLUSIONS:

Middle ear volume, calculated in a semiautomated fashion, is predictive of postsurgical audiometric outcomes, both independently and in combination with the conventional J-score.




Optimal Fat Suppression in Head and Neck MRI: Comparison of Multipoint Dixon with 2 Different Fat-Suppression Techniques, Spectral Presaturation and Inversion Recovery, and STIR [HEAD & NECK]

2018-02-13T08:00:48-08:00

BACKGROUND AND PURPOSE:

Uniform complete fat suppression is essential for identification and characterization of most head and pathology. Our aim was to compare the multipoint Dixon turbo spin-echo fat-suppression technique with 2 different fat-suppression techniques, including a hybrid spectral presaturation with inversion recovery technique and an inversion recovery STIR technique, in head and neck fat-suppression MR imaging.

MATERIALS AND METHODS:

Head and neck MR imaging datasets of 72 consecutive patients were retrospectively reviewed. All patients were divided into 2 groups based on the type of fat-suppression techniques used (group A: STIR and spectral presaturation with inversion recovery gadolinium-T1WI; group B: multipoint Dixon T2 TSE and multipoint Dixon gadolinium-T1WI TSE). Objective and subjective image quality and scan acquisition times were assessed and compared between multipoint Dixon T2 TSE versus STIR and multipoint Dixon gadolinium-T1WI TSE versus spectral presaturation with inversion recovery gadolinium-T1WI using the Mann-Whitney U test.

RESULTS:

A total of 64 patients were enrolled in the study (group A, n = 33 and group B, n = 31). Signal intensity ratios were significantly higher for multipoint Dixon T2 and gadolinium-T1WI techniques compared with STIR (P < .001) and spectral presaturation with inversion recovery gadolinium-T1WI (P < .001), respectively. Two independent blinded readers revealed that multipoint Dixon T2 and gadolinium-T1WI techniques had significantly higher overall image quality (P = .022 and P < .001) and fat-suppression grades (P < .013 and P < .001 across 3 different regions) than STIR and spectral presaturation with inversion recovery gadolinium-T1WI, respectively. The scan acquisition time was relatively short for the multipoint Dixon technique (2 minutes versus 4 minutes 56 seconds for the T2-weighted sequence and 2 minutes versus 3 minutes for the gadolinium-T1WI sequence).

CONCLUSIONS:

The multipoint Dixon technique offers better image quality and uniform fat suppression at a shorter scan time compared with STIR and spectral presaturation with inversion recovery gadolinium-T1WI techniques.




Optic Nerve Measurement on MRI in the Pediatric Population: Normative Values and Correlations [PEDIATRICS]

2018-02-13T08:00:48-08:00

BACKGROUND AND PURPOSE:

Few articles in the literature have looked at the diameter of the optic nerve on MR imaging, especially in children, in whom observations are subjective and no normative data exist. The aim of this study was to establish a data base for optic nerve diameter measurements on MR imaging in the pediatric population.

MATERIALS AND METHODS:

This was a retrospective study on the MR imaging of pediatric subjects (younger than 18 years of age) at the Department of Diagnostic Radiology at the American University of Beirut Medical Center, Beirut, Lebanon. The optic nerve measurements were obtained by 3 raters on axial and coronal sections at 3 mm (retrobulbar) and 7 mm (intraorbital) posterior to the lamina cribrosa.

RESULTS:

Of 211 scans of patients (422 optic nerves), 377 optic nerves were measured and included. Ninety-four patients were female (45%) and the median age at MR imaging was 8.6 years (interquartile range, 3.9–13.3 years). Optic nerves were divided into 5 age groups: 0–6 months (n = 18), 6 months–2 years (n = 44), 2–6 years (n = 86), 6–12 years (n = 120), and 12–18 years (n = 109). An increase in optic nerve diameter was observed with age, especially in the first 2 years of life. Measurements did not differ with eye laterality or sex.

CONCLUSIONS:

We report normative values of optic nerve diameter measured on MR imaging in children from birth to 18 years of age. A rapid increase in optic nerve diameter was demonstrated during the first 2 years of life, followed by a slower increase. This was independent of sex or eye laterality.




Measuring Cerebral and Cerebellar Glutathione in Children Using 1H MEGA-PRESS MRS [PEDIATRICS]

2018-02-13T08:00:48-08:00

BACKGROUND AND PURPOSE:

Glutathione is an important antioxidant in the human brain and therefore of interest in neurodegenerative disorders. The purpose of this study was to investigate the feasibility of measuring glutathione in healthy nonsedated children by using the 1H Mescher-Garwood point-resolved spectroscopy (MEGA-PRESS) sequence at 3T and to compare glutathione levels between the medial parietal gray matter and the cerebellum.

MATERIALS AND METHODS:

Glutathione was measured using MEGA-PRESS MRS (TR = 1.8 seconds, TE = 131 ms) in the parietal gray matter (35 x 25 x 20 mm3) of 6 healthy children (10.0 ± 2.4 years of age; range, 7–14 years; 3 males) and in the cerebellum of 11 healthy children (12.0 ± 2.7 years of age; range, 7–16 years; 6 males). A postprocessing pipeline was developed to account for frequency and phase variations in the edited ON and nonedited OFF spectra. Metabolites were quantified with LCModel and reported both as ratios and water-scaled values. Glutathione was quantified in the ON-OFF spectra, whereas total NAA, total Cho, total Cr, mIns, Glx, and taurine were quantified in the OFF spectra.

RESULTS:

We found significantly higher glutathione, total Cho, total Cr, mIns, and taurine in the cerebellum (P < .01). Glx and total NAA were significantly higher in the parietal gray matter (P < .01). There was no significant difference in glutathione/total Cr (P = .93) between parietal gray matter and cerebellum.

CONCLUSIONS:

We demonstrated that glutathione measurement in nonsedated children is feasible. We found significantly higher glutathione in the cerebellum compared with the parietal gray matter. Metabolite differences between the parietal gray matter and cerebellum agree with published MRS data in adults.




Temporal Lobe Malformations in Achondroplasia: Expanding the Brain Imaging Phenotype Associated with FGFR3-Related Skeletal Dysplasias [PEDIATRICS]

2018-02-13T08:00:48-08:00

SUMMARY:

Thanatophoric dysplasia, achondroplasia, and hypochondroplasia belong to the fibroblast growth factor receptor 3 (FGFR3) group of genetic skeletal disorders. Temporal lobe abnormalities have been documented in thanatophoric dysplasia and hypochondroplasia, and in 1 case of achondroplasia. We retrospectively identified 13 children with achondroplasia who underwent MR imaging of the brain between 2002 and 2015. All children demonstrated a deep transverse temporal sulcus on MR imaging. Further common neuroimaging findings were incomplete hippocampal rotation (12 children), oversulcation of the mesial temporal lobe (11 children), loss of gray-white matter differentiation of the mesial temporal lobe (5 children), and a triangular shape of the temporal horn (6 children). These appearances are very similar to those described in hypochondroplasia, strengthening the association of temporal lobe malformations in FGFR3-associated skeletal dysplasias.




Systematic Radiation Dose Reduction in Cervical Spine CT of Human Cadaveric Specimens: How Low Can We Go? [PATIENT SAFETY]

2018-02-13T08:00:48-08:00

BACKGROUND AND PURPOSE:

While the use of cervical spine CT in trauma settings has increased, the balance between image quality and dose reduction remains a concern. The purpose of our study was to compare the image quality of CT of the cervical spine of cadaveric specimens at different radiation dose levels.

MATERIALS AND METHODS:

The cervical spine of 4 human cadavers (mean body mass index; 30.5 ± 5.2 kg/m2; range, 24–36 kg/m2) was examined using different reference tube current–time products (45, 75, 105, 135, 150, 165, 195, 275, 355 mAs) and a tube voltage of 120 kV(peak). Data were reconstructed with filtered back-projection and iterative reconstruction. Qualitative image noise and morphologic characteristics of bony structures were quantified on a Likert scale. Quantitative image noise was measured. Statistics included analysis of variance and the Tukey test.

RESULTS:

Compared with filtered back-projection, iterative reconstruction provided significantly lower qualitative (mean noise score: iterative reconstruction = 2.10/filtered back-projection = 2.18; P = .003) and quantitative (mean SD of Hounsfield units in air: iterative reconstruction = 30.2/filtered back-projection = 51.8; P < .001) image noise. Image noise increased as the radiation dose decreased. Qualitative image noise at levels C1–4 was rated as either "no noise" or as "acceptable noise." Any shoulder position was at level C5 and caused more artifacts at lower levels. When we analyzed all spinal levels, scores for morphologic characteristics revealed no significant differences between 105 and 355 mAs (P = .555), but they were worse in scans at 75 mAs (P = .025).

CONCLUSIONS:

Clinically acceptable image quality of cervical spine CTs for evaluation of bony structures of cadaveric specimens with different body habitus can be achieved with a reference mAs of 105 at 120 kVp with iterative reconstruction. Pull-down of shoulders during acquisition could improve image quality but may not be feasible in trauma patients with unknown injuries.




Clinical and Radiologic Characteristics of Deep Lumbosacral Dural Arteriovenous Fistulas [SPINE]

2018-02-13T08:00:48-08:00

BACKGROUND AND PURPOSE:

Spinal dural arteriovenous fistulas located in the deep lumbosacral region are rare and the most difficult to diagnose among spinal dural arteriovenous fistulas located elsewhere in the spinal dura. Specific clinical and radiologic features of these fistulas are still inadequately reported and are the subject of this study.

MATERIALS AND METHODS:

We retrospectively evaluated all data of patients with spinal dural arteriovenous fistulas treated and/or diagnosed in our institution between 1990 and 2017. Twenty patients with deep lumbosacral spinal dural arteriovenous fistulas were included in this study.

RESULTS:

The most common neurologic findings at the time of admission were paraparesis (85%), sphincter dysfunction (70%), and sensory disturbances (20%). Medullary T2 hyperintensity and contrast enhancement were present in most cases. The filum vein and/or lumbar veins were dilated in 19/20 (95%) patients. Time-resolved contrast-enhanced dynamic MRA indicated a spinal dural arteriovenous fistula at or below the L5 vertebral level in 7/8 (88%) patients who received time-resolved contrast-enhanced dynamic MRA before DSA. A bilateral arterial supply of the fistula was detected via DSA in 5 (25%) patients.

CONCLUSIONS:

Clinical symptoms caused by deep lumbosacral spinal dural arteriovenous fistulas are comparable with those of spinal dural arteriovenous fistulas at other locations. Medullary congestion in association with an enlargement of the filum vein or other lumbar radicular veins is a characteristic finding in these patients. Spinal time-resolved contrast-enhanced dynamic MRA facilitates the detection of the drainage vein and helps to localize deep lumbosacral-located fistulas with a high sensitivity before DSA. Definite detection of these fistulas remains challenging and requires sufficient visualization of the fistula-supplying arteries and draining veins by conventional spinal angiography.




Cervical Cord Atrophy and Long-Term Disease Progression in Patients with Primary-Progressive Multiple Sclerosis [SPINE]

2018-02-13T08:00:48-08:00

BACKGROUND AND PURPOSE:

Cervical cord atrophy has been associated with clinical disability in multiple sclerosis and is proposed as an outcome measure of neurodegeneration. The aim of this study was to quantify the development of cervical cord atrophy and to evaluate its association with disability progression in patients with primary-progressive multiple sclerosis.

MATERIALS AND METHODS:

Thirty-one patients with primary-progressive multiple sclerosis underwent 1.5T brain and spinal cord MR imaging at baseline and 6–7 years later. The cervical spinal cord from C1 to C5 was segmented to evaluate the normalized overall cross-sectional area and the cross-sectional area of C2–C3, C3–C4, and C4–C5. The annualized rates of normalized cross-sectional area loss were also evaluated. To estimate clinical progression, we determined the Expanded Disability Status Scale score at baseline and at 2 and 14 years after baseline to compute the normalized area under the curve of the Expanded Disability Status Scale and the Expanded Disability Status Scale changes from baseline to the follow-up time points. Associations between the cord cross-sectional area and brain MR imaging and clinical measures were also investigated. Finally, the value of all these measures for predicting long-term disability was evaluated.

RESULTS:

Some normalized cross-sectional area measurements showed moderate correlations with the normalized area under the curve of the Expanded Disability Status Scale, ranging from –0.439 to –0.359 (P < .05). Moreover, the annualized rate of the normalized mean cross-sectional area loss and the baseline Expanded Disability Status Scale were independent predictors of long-term disability progression.

CONCLUSIONS:

These data indicate that development of cervical cord atrophy is associated with progression of disability and is predictive of this event in patients with primary-progressive MS.




[other]

2018-01-11T08:00:42-08:00







Health Care Economics: A Study Guide for Neuroradiology Fellows, Part 1 [review-article]

2018-01-11T08:00:42-08:00

SUMMARY:

Few resources are available in the medical literature for a comprehensive review of current health care economics as it relates to radiologists, specifically framed by topics defined by the Accreditation Council for Graduate Medical Education in the evaluation of neuroradiology fellows. Therefore, we present a comprehensive review article as a study guide for fellows to learn from and gain competence in the Accreditation Council for Graduate Medical Education neuroradiology milestones on health care economics.










Reply: [LETTERS]

2018-01-11T08:00:42-08:00




Erratum [ERRATA]

2018-01-11T08:00:42-08:00




Health Care Economics: A Study Guide for Neuroradiology Fellows, Part 2 [review-article]

2018-01-11T08:00:42-08:00

SUMMARY:

In this second article, we continue the review of current health care economics as it relates to radiologists, specifically framed by topics defined by the Accreditation Council for Graduate Medical Education in the evaluation of neuroradiology fellows. The discussion in this article is focused on topics pertaining to levels 4 and 5, which are the more advanced levels of competency defined by the Accreditation Council for Graduate Medical Education Neuroradiology Milestones on Health Care Economics and System Based Practice.




Influences for Gender Disparity in Academic Neuroradiology [research-article]

2018-01-11T08:00:42-08:00

BACKGROUND AND PURPOSE:

There has been extensive interest in promoting gender equality within radiology, a predominately male field. In this study, our aim was to quantify gender representation in neuroradiology faculty rankings and determine any related factors that may contribute to any such disparity.

MATERIALS AND METHODS:

We evaluated the academic and administrative faculty members of neuroradiology divisions for all on-line listed programs in the US and Canada. After excluding programs that did not fulfill our selection criteria, we generated a short list of 85 US and 8 Canadian programs. We found 465 faculty members who met the inclusion criteria for our study. We used Elsevier's SCOPUS for gathering the data pertaining to the publications, H-index, citations, and tenure of the productivity of each faculty member.

RESULTS:

Gender disparity was insignificant when analyzing academic ranks. There are more men working in neuroimaging relative to women (2 = 0.46; P = .79). However, gender disparity was highly significant for leadership positions in neuroradiology (2 = 6.76; P = .009). The median H-index was higher among male faculty members (17.5) versus female faculty members (9). Female faculty members have odds of 0.84 compared with male faculty members of having a higher H-index, adjusting for publications, citations, academic ranks, leadership ranks, and interaction between gender and publications and gender and citations (9).

CONCLUSIONS:

Neuroradiology faculty members follow the same male predominance seen in many other specialties of medicine. In this study, issues such as mentoring, role models, opportunities to engage in leadership/research activities, funding opportunities, and mindfulness regarding research productivity are explored.




Deep Brain Nuclei T1 Shortening after Gadobenate Dimeglumine in Children: Influence of Radiation and Chemotherapy [PATIENT SAFETY]

2018-01-11T08:00:42-08:00

BACKGROUND AND PURPOSE:

Intrinsic T1-hyperintense signal has recently been reported in the deep gray nuclei on brain MR imaging after multiple doses of gadolinium-based contrast agents. Most reports have included adult patients and excluded those undergoing radiation or chemotherapy. We investigated whether T1 shortening is also observed in children and tried to determine whether radiochemotherapy is a risk factor for this phenomenon.

MATERIALS AND METHODS:

In this single-center retrospective study, we reviewed clinical charts and images of all patients 18 years of age or younger with ≥4 gadobenate dimeglumine–enhanced MRIs for 6 years. Seventy-six children (mean age, 9.3 years; 60 unconfounded by treatment, 16 with radiochemotherapy) met the selection criteria (>4 MR imaging examinations; mean, 8). T1 signal intensity ratios for the dentate to pons and globus pallidus to thalamus were calculated and correlated with number of injections, time interval, and therapy.

RESULTS:

Among the 60 children without radiochemotherapy, only 2 had elevated T1 signal intensity ratios (n = 20 and 16 injections). Twelve of the 16 children with radiochemotherapy showed elevated signal intensity ratios. Statistical analysis demonstrated a significant signal intensity ratio change for the number of injections (P < .001) and amount of gadolinium (P = .008), but not for the interscan time interval (P = .35). There was a significant difference in the average signal intensity ratio change between those with and without radiochemotherapy (P < .001). Chart review revealed no new neurologic deficits in any patients, related to their underlying conditions and prior surgeries.

CONCLUSIONS:

Compared with published adult series, children show a similar pattern of T1 hyperintense signal changes of the dentate and globus pallidus after multiple gadobenate dimeglumine injections. The T1 signal changes in children may have a later onset but are accelerated by radiochemotherapy.




MR Elastography Analysis of Glioma Stiffness and IDH1-Mutation Status [ADULT BRAIN]

2018-01-11T08:00:42-08:00

BACKGROUND AND PURPOSE:

Our aim was to noninvasively evaluate gliomas with MR elastography to characterize the relationship of tumor stiffness with tumor grade and mutations in the isocitrate dehydrogenase 1 (IDH1) gene.

MATERIALS AND METHODS:

Tumor stiffness properties were prospectively quantified in 18 patients (mean age, 42 years; 6 women) with histologically proved gliomas using MR elastography from 2014 to 2016. Images were acquired on a 3T MR imaging unit with a vibration frequency of 60 Hz. Tumor stiffness was compared with unaffected contralateral white matter, across tumor grade, and by IDH1-mutation status. The performance of the use of tumor stiffness to predict tumor grade and IDH1 mutation was evaluated with the Wilcoxon rank sum, 1-way ANOVA, and Tukey-Kramer tests.

RESULTS:

Gliomas were softer than healthy brain parenchyma, 2.2 kPa compared with 3.3 kPa (P < .001), with grade IV tumors softer than grade II. Tumors with an IDH1 mutation were significantly stiffer than those with wild type IDH1, 2.5 kPa versus 1.6 kPa, respectively (P = .007).

CONCLUSIONS:

MR elastography demonstrated that not only were gliomas softer than normal brain but the degree of softening was directly correlated with tumor grade and IDH1-mutation status. Noninvasive determination of tumor grade and IDH1 mutation may result in improved stratification of patients for different treatment options and the evaluation of novel therapeutics. This work reports on the emerging field of "mechanogenomics": the identification of genetic features such as IDH1 mutation using intrinsic biomechanical information.




Prediction of IDH1-Mutation and 1p/19q-Codeletion Status Using Preoperative MR Imaging Phenotypes in Lower Grade Gliomas [ADULT BRAIN]

2018-01-11T08:00:42-08:00

BACKGROUND AND PURPOSE:

WHO grade II gliomas are divided into three classes: isocitrate dehydrogenase (IDH)-wildtype, IDH-mutant and no 1p/19q codeletion, and IDH-mutant and 1p/19q-codeleted. Different molecular subtypes have been reported to have prognostic differences and different chemosensitivity. Our aim was to evaluate the predictive value of imaging phenotypes assessed with the Visually AcceSAble Rembrandt Images lexicon for molecular classification of lower grade gliomas.

MATERIALS AND METHODS:

MR imaging scans of 175 patients with lower grade gliomas with known IDH1 mutation and 1p/19q-codeletion status were included (78 grade II and 97 grade III) in the discovery set. MR imaging features were reviewed by using Visually AcceSAble Rembrandt Images (VASARI); their associations with molecular markers were assessed. The predictive power of imaging features for IDH1-wild type tumors was evaluated using the Least Absolute Shrinkage and Selection Operator. We tested the model in a validation set (40 subjects).

RESULTS:

Various imaging features were significantly different according to IDH1 mutation. Nonlobar location, larger proportion of enhancing tumors, multifocal/multicentric distribution, and poor definition of nonenhancing margins were independent predictors of an IDH1 wild type according to the Least Absolute Shrinkage and Selection Operator. The areas under the curve for the prediction model were 0.859 and 0.778 in the discovery and validation sets, respectively. The IDH1-mutant, 1p/19q-codeleted group frequently had mixed/restricted diffusion characteristics and showed more pial invasion compared with the IDH1-mutant, no codeletion group.

CONCLUSIONS:

Preoperative MR imaging phenotypes are different according to the molecular markers of lower grade gliomas, and they may be helpful in predicting the IDH1-mutation status.




Improved Spatiotemporal Resolution of Dynamic Susceptibility Contrast Perfusion MRI in Brain Tumors Using Simultaneous Multi-Slice Echo-Planar Imaging [ADULT BRAIN]

2018-01-11T08:00:42-08:00

SUMMARY:

DSC perfusion MR imaging in brain tumors requires a trade-off between spatial and temporal resolution, resulting in less spatial coverage to meet the temporal resolution requirements for accurate relative CBV estimation. DSC-MR imaging could potentially benefit from the advantages associated with simultaneous multi-slice imaging, including increased spatiotemporal resolution. In the current article, we demonstrate how simultaneous multi-slice EPI can be used to improve DSC-MR imaging spatiotemporal resolution in patients with glioblastoma.




Reproducibility of Deep Gray Matter Atrophy Rate Measurement in a Large Multicenter Dataset [ADULT BRAIN]

2018-01-11T08:00:42-08:00

BACKGROUND AND PURPOSE:

Precise in vivo measurement of deep GM volume change is a highly demanded prerequisite for an adequate evaluation of disease progression and new treatments. However, quantitative data on the reproducibility of deep GM structure volumetry are not yet available. In this paper we aim to investigate this reproducibility using a large multicenter dataset.

MATERIALS AND METHODS:

We have assessed the reproducibility of 2 automated segmentation software packages (FreeSurfer and the FMRIB Integrated Registration and Segmentation Tool) by quantifying the volume changes of deep GM structures by using back-to-back MR imaging scans from the Alzheimer Disease Neuroimaging Initiative's multicenter dataset. Five hundred sixty-two subjects with scans at baseline and 1 year were included. Reproducibility was investigated in the bilateral caudate nucleus, putamen, amygdala, globus pallidus, and thalamus by carrying out descriptives as well as multilevel and variance component analysis.

RESULTS:

Median absolute back-to-back differences varied between GM structures, ranging from 59.6–156.4 μL for volume change, and 1.26%–8.63% for percentage volume change. FreeSurfer had a better performance for the outcome of longitudinal volume change for the bilateral amygdala, putamen, left caudate nucleus (P < .005), and right thalamus (P < .001). For longitudinal percentage volume change, Freesurfer performed better for the left amygdala, bilateral caudate nucleus, and left putamen (P < .001). Smaller limits of agreement were found for FreeSurfer for both outcomes for all GM structures except the globus pallidus. Our results showed that back-to-back differences in 1-year percentage volume change were approximately 1.5–3.5 times larger than the mean measured 1-year volume change of those structures.

CONCLUSIONS:

Longitudinal deep GM atrophy measures should be interpreted with caution. Furthermore, deep GM atrophy measurement techniques require substantially improved reproducibility, specifically when aiming for personalized medicine.




Brain Structural Changes following HIV Infection: Meta-Analysis [ADULT BRAIN]

2018-01-11T08:00:42-08:00

BACKGROUND:

Numerous studies have used structural neuroimaging to measure HIV effects on brain macroarchitecture. While many have reported changes in total brain volume, gray matter volume, white matter volume, CSF volume, and basal ganglia volume following HIV infection, quantitative inconsistencies observed across studies are large.

PURPOSE:

Our aim was to evaluate the consistency and temporal stability of serostatus effects on a range of structural neuroimaging measures.

DATA SOURCES:

PubMed, reference lists, and corresponding authors.

STUDY SELECTION:

The meta-analysis included 19 cross-sectional studies reporting HIV effects on cortical and subcortical volume from 1993 to 2016.

DATA ANALYSIS:

Random-effects meta-analysis was used to estimate individual study standardized mean differences and study heterogeneity. Meta-regression was used to examine the effects of the study publication year.

DATA SYNTHESIS:

Meta-analysis revealed standardized mean differences related to the serostatus of –0.65 (P = .002) for total brain volume, –0.28 for gray matter volume (P = .008), –0.24 (P = .076) for white matter volume, and 0.56 (P = .001) for CSF volume. Basal ganglia volume differences related to serostatus were not significant. Nevertheless, estimates of between-study heterogeneity suggested that much of the observed variance was between studies. Publication year was associated with recent reductions in many neurostructural effects.

LIMITATIONS:

Many studies pooled participants with varying durations of treatment, disease, and comorbidities. Image-acquisition methods changed with time.

CONCLUSIONS:

While published studies of HIV effects on brain structure had substantial variations that are likely to result from changes in HIV treatment practice during the study period, quantitative neurostructural measures can reliably detect the effects of HIV infection during treatment, serving as reliable biomarkers.




Semiautomated Evaluation of the Primary Motor Cortex in Patients with Amyotrophic Lateral Sclerosis at 3T [ADULT BRAIN]

2018-01-11T08:00:42-08:00

BACKGROUND AND PURPOSE:

Amyotrophic lateral sclerosis is a neurodegenerative disease involving the upper and lower motor neurons. In amyotrophic lateral sclerosis, pathologic changes in the primary motor cortex include Betz cell depletion and the presence of reactive iron-loaded microglia, detectable on 7T MR images as atrophy and T2*-hypointensity. Our purposes were the following: 1) to investigate the signal hypointensity-to-thickness ratio of the primary motor cortex as a radiologic marker of upper motor neuron involvement in amyotrophic lateral sclerosis with a semiautomated method at 3T, 2) to compare 3T and 7T results, and 3) to evaluate whether semiautomated measurement outperforms visual image assessment.

MATERIALS AND METHODS:

We investigated 27 patients and 13 healthy subjects at 3T, and 19 patients and 18 healthy subjects at 7T, performing a high-resolution 3D multiecho T2*-weighted sequence targeting the primary motor cortex. The signal hypointensity-to-thickness ratio of the primary motor cortex was calculated with a semiautomated method depicting signal intensity profiles of the cortex. Images were also visually classified as "pathologic" or "nonpathologic" based on the primary motor cortex signal intensity and thickness.

RESULTS:

The signal hypointensity-to-thickness ratio of the primary motor cortex was greater in patients than in controls (P < .001), and it correlated with upper motor neuron impairment in patients ( = 0.57, P < .001). The diagnostic accuracy of the signal hypointensity-to-thickness ratio was high at 3T (area under the curve = 0.89) and even higher at 7T (area under the curve = 0.94). The sensitivity of the semiautomated method (0.81) outperformed the sensitivity of the visual assessment (0.56–0.63) at 3T.

CONCLUSIONS:

The signal hypointensity-to-thickness ratio of the primary motor cortex calculated with a semiautomated method is suggested as a radiologic marker of upper motor neuron burden in patients with amyotrophic lateral sclerosis. This semiautomated method may be useful for improving the subjective radiologic evaluation of upper motor neuron pathology in patients suspected of having amyotrophic lateral sclerosis.




Perivascular Spaces in Old Age: Assessment, Distribution, and Correlation with White Matter Hyperintensities [ADULT BRAIN]

2018-01-11T08:00:42-08:00

BACKGROUND AND PURPOSE:

The visual rating scales for perivascular spaces vary considerably. We sought to develop a new scale for visual assessment of perivascular spaces and to further describe their distribution and association with white matter hyperintensities in old age.

MATERIALS AND METHODS:

This population-based study included 530 individuals who did not have dementia and were not institutionalized (age, ≥60 years or older; mean age, 70.7 years; 58.9% women) who were living in central Stockholm, Sweden. A semiquantitative visual rating scale was developed to score the number and size of visible perivascular spaces in 7 brain regions in each hemisphere. A modified Scheltens visual rating scale was used to assess white matter hyperintensities.

RESULTS:

The global scores for perivascular spaces ranged from 4–32 for number, 3–22 for size, and 7–54 for the combination of number and size. The weighted statistics for the intra- and interrater reliability both were 0.77. The global score for the number of perivascular spaces increased with advancing age (P < .001). The scores for the number of perivascular spaces in the basal ganglia and subinsular regions were significantly correlated with the load of white matter hyperintensities, especially in lobar and deep white matter regions (partial correlation coefficients, >0.223; P < .01).

CONCLUSIONS:

The new visual rating scale for perivascular spaces shows excellent intra- and interrater reliability. The number of perivascular spaces globally and, especially, in the basal ganglia, is correlated with the load of lobar and deep white matter hyperintensities, supporting the view that perivascular spaces are a marker for cerebral small-vessel disease.




Do Fluid-Attenuated Inversion Recovery Vascular Hyperintensities Represent Good Collaterals before Reperfusion Therapy? [ADULT BRAIN]

2018-01-11T08:00:42-08:00

BACKGROUND AND PURPOSE:

In acute ischemic stroke, whether FLAIR vascular hyperintensities represent good or poor collaterals remains controversial. We hypothesized that extensive FLAIR vascular hyperintensities correspond to good collaterals, as indirectly assessed by the hypoperfusion intensity ratio.

MATERIALS AND METHODS:

We included 244 consecutive patients eligible for reperfusion therapy with MCA stroke and pretreatment MR imaging with both FLAIR and PWI. The FLAIR vascular hyperintensity score was based on ASPECTS, ranging from 0 (no FLAIR vascular hyperintensity) to 7 (FLAIR vascular hyperintensities abutting all ASPECTS cortical areas). The hypoperfusion intensity ratio was defined as the ratio of the time-to-maximum >10-second over time-to-maximum >6-second lesion volumes. The median hypoperfusion intensity ratio was used to dichotomize good (low hypoperfusion intensity ratio) versus poor (high hypoperfusion intensity ratio) collaterals. We then studied the association between FLAIR vascular hyperintensity extent and hypoperfusion intensity ratio.

RESULTS:

Hypoperfusion was present in all patients, with a median hypoperfusion intensity ratio of 0.35 (interquartile range, 0.19–0.48). The median FLAIR vascular hyperintensity score was 4 (interquartile range, 3–5). The FLAIR vascular hyperintensities were more extensive in patients with good collaterals (hypoperfusion intensity ratio ≤0.35) than with poor collaterals (hypoperfusion intensity ratio >0.35; P for Trend = .016). The FLAIR vascular hyperintensity score was independently associated with good collaterals (P for Trend = .002).

CONCLUSIONS:

In patients eligible for reperfusion therapy, FLAIR vascular hyperintensity extent was associated with good collaterals, as assessed by the pretreatment hypoperfusion intensity ratio. The ASPECTS assessment of FLAIR vascular hyperintensities could be used to rapidly identify patients more likely to benefit from reperfusion therapy.




Can Arterial Spin-Labeling with Multiple Postlabeling Delays Predict Cerebrovascular Reserve? [ADULT BRAIN]

2018-01-11T08:00:42-08:00

BACKGROUND AND PURPOSE:

The effect of delayed transit time is the main source of error in the quantitative measurement of CBF in arterial spin-labeling. In the present study, we evaluated the usefulness of the transit time–corrected CBF and arterial transit time delay from multiple postlabeling delays arterial spin-labeling compared with basal/acetazolamide stress technetium Tc99m-hexamethylpropylene amineoxime (Tc99m-HMPAO) SPECT in predicting impairment in the cerebrovascular reserve.

MATERIALS AND METHODS:

Transit time–corrected CBF maps and arterial transit time maps were acquired in 30 consecutive patients with unilateral ICA or MCA steno-occlusive disease (severe stenosis or occlusion). Internal carotid artery territory–based ROIs were applied to both perfusion maps. Additionally, impairment in the cerebrovascular reserve was evaluated according to both qualitative and quantitative analyses of the ROIs on basal/acetazolamide stress Tc99m-HMPAO SPECT using a previously described method. The area under the receiver operating characteristic curve was used to evaluate the diagnostic accuracy of arterial spin-labeling in depicting impairment of the cerebrovascular reserve. The correlation between arterial spin-labeling and cerebrovascular reserve was evaluated.

RESULTS:

The affected hemisphere had a decreased transit time–corrected CBF and increased arterial transit time compared with the corresponding values of the contralateral normal hemisphere, which were statistically significant (P < .001). The percentage change of transit time–corrected CBF and the percentage change of arterial transit time were independently differentiating variables (P < .001) for predicting cerebrovascular reserve impairment. The correlation coefficient between the arterial transit time and cerebrovascular reserve index ratio was –0.511.

CONCLUSIONS:

Our results demonstrate that the transit time–corrected CBF and arterial transit time based on arterial spin-labeling perfusion MR imaging can predict cerebrovascular reserve impairment.




Spatial Correlation of Pathology and Perfusion Changes within the Cortex and White Matter in Multiple Sclerosis [ADULT BRAIN]

2018-01-11T08:00:42-08:00

BACKGROUND AND PURPOSE:

The spatial correlation between WM and cortical GM disease in multiple sclerosis is controversial and has not been previously assessed with perfusion MR imaging. We sought to determine the nature of association between lobar WM, cortical GM, volume and perfusion.

MATERIALS AND METHODS:

Nineteen individuals with secondary-progressive multiple sclerosis, 19 with relapsing-remitting multiple sclerosis, and 19 age-matched healthy controls were recruited. Quantitative MR perfusion imaging was used to derive CBF, CBV, and MTT within cortical GM, WM, and T2-hyperintense lesions. A 2-step multivariate linear regression (corrected for age, disease duration, and Expanded Disability Status Scale) was used to assess correlations between perfusion and volume measures in global and lobar normal-appearing WM, cortical GM, and T2-hyperintense lesions. The Bonferroni adjustment was applied as appropriate.

RESULTS:

Global cortical GM and WM volume was significantly reduced for each group comparison, except cortical GM volume of those with relapsing-remitting multiple sclerosis versus controls. Global and lobar cortical GM CBF and CBV were reduced in secondary-progressive multiple sclerosis compared with other groups but not for relapsing-remitting multiple sclerosis versus controls. Global and lobar WM CBF and CBV were not significantly different across groups. The distribution of lobar cortical GM and WM volume reduction was disparate, except for the occipital lobes in patients with secondary-progressive multiple sclerosis versus those with relapsing-remitting multiple sclerosis. Moderate associations were identified between lobar cortical GM and lobar normal-appearing WM volume in controls and in the left temporal lobe in relapsing-remitting multiple sclerosis. No significant associations occurred between cortical GM and WM perfusion or volume. Strong correlations were observed between cortical-GM perfusion, normal appearing WM and lesional perfusion, with respect to each global and lobar region within HC, and RRMS and SPMS patients (R2 ≤ 0.96, P < .006 and R2 ≤ 0.738, P < .006).

CONCLUSIONS:

The weak correlation between lobar WM and cortical GM volume loss and perfusion reduction suggests the independent pathophysiology of WM and cortical GM disease.




Association of Developmental Venous Anomalies with Demyelinating Lesions in Patients with Multiple Sclerosis [ADULT BRAIN]

2018-01-11T08:00:42-08:00

SUMMARY:

We present 5 cases of demyelination in patients diagnosed with multiple sclerosis that are closely associated with a developmental venous anomaly. Although the presence of a central vein is a known phenomenon with multiple sclerosis plaques, demyelination occurring around developmental venous anomalies is an underreported phenomenon. Tumefactive demyelination can cause a diagnostic dilemma because of its overlapping imaging findings with central nervous system neoplasm. The relationship of a tumefactive plaque with a central vein can be diagnostically useful, and we suggest that if such a lesion is closely associated with a developmental venous anomaly, an inflammatory or demyelinating etiology should be a leading consideration.




Time for a Time Window Extension: Insights from Late Presenters in the ESCAPE Trial [INTERVENTIONAL]

2018-01-11T08:00:42-08:00

BACKGROUND AND PURPOSE:

The safety and efficacy of endovascular therapy for large-artery stroke in the extended time window is not yet well-established. We performed a subgroup analysis on subjects enrolled within an extended time window in the Endovascular Treatment for Small Core and Proximal Occlusion Ischemic Stroke (ESCAPE) trial.

MATERIALS AND METHODS:

Fifty-nine of 315 subjects (33 in the intervention group and 26 in the control group) were randomized in the ESCAPE trial between 5.5 and 12 hours after last seen healthy (likely to have groin puncture administered 6 hours after that). Treatment effect sizes for all relevant outcomes (90-day mRS shift, mRS 0–2, mRS 0–1, and 24-hour NIHSS scores and intracerebral hemorrhage) were reported using unadjusted and adjusted analyses.

RESULTS:

There was no evidence of treatment heterogeneity between subjects in the early and late windows. Treatment effect favoring intervention was seen across all clinical outcomes in the extended time window (absolute risk difference of 19.3% for mRS 0–2 at 90 days). There were more asymptomatic intracerebral hemorrhage events within the intervention arm (48.5% versus 11.5%, P = .004) but no difference in symptomatic intracerebral hemorrhage.

CONCLUSIONS:

Patients with an extended time window could potentially benefit from endovascular treatment. Ongoing randomized controlled trials using imaging to identify late presenters with favorable brain physiology will help cement the paradigm of using time windows to select the population for acute imaging and imaging to select individual patients for therapy.




Posttreatment Infarct Volumes when Compared with 24-Hour and 90-Day Clinical Outcomes: Insights from the REVASCAT Randomized Controlled Trial [INTERVENTIONAL]

2018-01-11T08:00:42-08:00

BACKGROUND AND PURPOSE:

Endovascular therapy has become the standard of care for patients with disabling anterior circulation ischemic stroke due to proximal intracranial thrombi. Our aim was to determine whether the beneficial effect of endovascular treatment on functional outcome could be explained by a reduction in posttreatment infarct volume in the Endovascular Revascularization With Solitaire Device Versus Best Medical Therapy in Anterior Circulation Stroke Within 8 Hours (REVASCAT) trial.

MATERIALS AND METHODS:

The REVASCAT trial was a multicenter randomized open-label trial with blinded outcome evaluation. Among 206 enrolled subjects (endovascular treatment, n = 103; control, n = 103), posttreatment infarct volume was measured in 204 subjects. Posttreatment infarct volumes were compared with treatment assignment and recanalization status. Appropriate statistical models were used to assess the relationship among baseline clinical and imaging variables, posttreatment infarct volume, the 24-hour NIHSS score, and functional status with the 90-day modified Rankin Scale score.

RESULTS:

The median posttreatment infarct volume in all subjects was 23.7 mL (interquartile range = 68.9 mL) and 16.3 mL (interquartile range = 50.2 mL) in the endovascular treatment arm and 38.6 mL (interquartile range = 74.9 mL) in the control arm (P = .02 for endovascular treatment versus control subjects). Baseline NIHSS (P < .01), site of occlusion (P < .03), baseline NCCT ASPECTS (P < .01), and recanalization status (P = .02) were independently associated with posttreatment infarct volume. Baseline NIHSS (P < .01), time from symptom onset to randomization (P = .02), treatment type (P = .04), and recanalization status (P < .01) were independently associated with the 24-hour NIHSS scores. The 24-hour NIHSS score strongly mediated the relationship between treatment type and 90-day mRS (P < .01 for indirect effect when adjusted for age), while posttreatment infarct volume did not (P = .26).

CONCLUSIONS:

Endovascular treatment saves brain and improves 90-day clinical outcomes primarily through a beneficial effect on the 24-hour stroke severity.




Two-Center Experience in the Endovascular Treatment of Ruptured and Unruptured Intracranial Aneurysms Using the WEB Device: A Retrospective Analysis [INTERVENTIONAL]

2018-01-11T08:00:42-08:00

BACKGROUND AND PURPOSE:

The safety and efficacy of the Woven EndoBridge (WEB) device for the treatment of cerebral aneurysms has been investigated in several studies. Our objective was to report the experience of 2 neurovascular centers with the WEB device in the treatment of broad-based intracranial aneurysms, including the technical feasibility and safety as well as short- and midterm angiographic and clinical follow-up-results.

MATERIALS AND METHODS:

We performed a retrospective analysis of all ruptured and unruptured aneurysms treated with a WEB device (WEB Single-Layer and Single-Layer Sphere) between August 2014 and February 2017. Primary outcome measures included the feasibility of implantation and the angiographic outcome. Secondary outcome measures included the clinical outcome at discharge and procedural complications.

RESULTS:

One hundred two aneurysms in 101 patients, including 37 (36.3%) ruptured aneurysms, were treated with the WEB device. Implantation was successful in 98 (96.1%) aneurysms. Additional devices (stents/coils) were necessary in 15.3% (15/98) of aneurysms. Procedural complications occurred in 4.9% (5/102). Of these, 4 were thromboembolic events and 1 was an intraprocedural rupture. Angiographic follow-up at 3 and 12 months was available for 79.6% (78/98) and 50.0% (49/98) of all aneurysms to date, respectively, showing a sufficient aneurysm occlusion in 80.7% (63/78) at 3 months and 77.6% (38/49) at 12 months. Delayed aneurysm ruptures have not been observed during the follow-up period to date.

CONCLUSIONS:

The WEB device offers a safe and effective treatment option for broad-based intracranial aneurysms without the need for dual antiplatelet therapy.




Hemodynamic Changes Caused by Multiple Stenting in Vertebral Artery Fusiform Aneurysms: A Patient-Specific Computational Fluid Dynamics Study [INTERVENTIONAL]

2018-01-11T08:00:42-08:00

BACKGROUND AND PURPOSE:

The multiple stent placement technique has largely improved the long-term outcomes of intracranial fusiform aneurysms, but the hemodynamic mechanisms remain unclear. In this study, we analyzed the hemodynamic changes caused by different stent-placement strategies in patient-specific models using the computational fluid dynamics technique, aiming to provide evidence for clinical decision-making.

MATERIALS AND METHODS:

Ten vertebral artery fusiform aneurysms were included, and their patient-specific computational fluid dynamics models were reconstructed. A fast virtual stent placement technique was used to simulate sequential multiple stent placements (from a single stent to triple stents) in the vertebral artery fusiform aneurysm models. Hemodynamic parameters, including wall shear stress, pressure, oscillatory shear index, relative residence time, and flow pattern, were calculated and compared among groups with different numbers of stents.

RESULTS:

Virtual stents were deployed in all 10 cases successfully, consistent with the real stent configuration. Wall shear stress decreased progressively by 7.2%, 20.6%, and 25.8% as the number of stents increased. Meanwhile, relative residence time and pressure increased on average by 11.3%, 15.4%, and 45.0% and by 15.7%, 21.5%, and 28.2%. The oscillatory shear index showed no stable variation trend. Flow patterns improved by weakening the intensity of the vortices and displacing the vortex center from the aneurysmal wall.

CONCLUSIONS:

Stent placement modifies hemodynamic patterns in vertebral artery fusiform aneurysms, which might favor thrombosis formation in the aneurysmal sac. This effect is amplified with the number of stents deployed. However, a potential risk of rupture or recanalization exists and should be considered when planning to use the multiple stent placement technique in vertebral artery fusiform aneurysms.




Lower Arterial Cross-Sectional Area of Carotid and Vertebral Arteries and Higher Frequency of Secondary Neck Vessels Are Associated with Multiple Sclerosis [ADULT BRAIN]

2018-01-11T08:00:42-08:00

BACKGROUND AND PURPOSE:

Arterial and neck vessel system characteristics of patients with multiple sclerosis have not been previously investigated. Therefore, the aim of this study was to examine the frequency of neck vessels and their cross-sectional areas (in square millimeters) between patients with MS and healthy controls.

MATERIALS AND METHODS:

In this study, 193 patients with MS and 193 age- and sex-matched healthy controls underwent 2D TOF venography at 3T. The main arterial (carotid and vertebral), venous (internal jugular), and secondary neck vessels were examined at 4 separate cervical levels (C2/3, C4, C5/6, and C7/T1). The ANCOVA adjusted for age, body mass index, smoking status, hypertension, and heart disease was used to compare the differences between patients with MS and healthy controls.

RESULTS:

After controlling for all confounding factors, patients with MS had significantly lower cross-sectional areas of the carotid arteries at the C2/3 (P = .03), C5/6 (P = .026), and C7/T1 (P = .005) levels as well as of the vertebral arteries at the C2/3 (P = .02), C4 (P = .012), and C7/T1 (P = .006) levels, compared with healthy controls. A higher frequency of secondary neck vessels was found at all 4 levels in patients with MS: C2/3 (12.9 versus 10, P < .001), C4 (9.1 versus 7.5, P < .001), C5/6 (7.8 versus 6.8, P = .012), and C7/T1 (8.8 versus 6, P < .001). The total cross-sectional areas of secondary neck vessels were also significantly higher at all 4 levels (P < .03). No significant differences in the cross-sectional areas of jugular veins were found between patients with MS and healthy controls.

CONCLUSIONS:

Patients with MS showed lower cross-sectional areas of the carotid and vertebral arteries and a higher frequency of secondary neck vessels and their cross-sectional areas compared with healthy controls.




CT Attenuation Analysis of Carotid Intraplaque Hemorrhage [EXTRACRANIAL VASCULAR]

2018-01-11T08:00:42-08:00

BACKGROUND AND PURPOSE: Intraplaque hemorrhage is considered a leading parameter of carotid plaque vulnerability. Our purpose was to assess the CT characteristics of intraplaque hemorrhage with histopathologic correlation to identify features that allow for confirming or ruling out the intraplaque hemorrhage. MATERIALS AND METHODS: This retrospective study included 91 patients (67 men; median age, 65 ± 7 years; age range, 41–83 years) who underwent CT angiography and carotid endarterectomy from March 2010 to May 2013. Histopathologic analysis was performed for the tissue characterization and identification of intraplaque hemorrhage. Two observers assessed the plaque's attenuation values by using an ROI (≥ 1 and ≤2 mm2). Receiver operating characteristic curve, Mann-Whitney, and Wilcoxon analyses were performed. RESULTS: A total of 169 slices were assessed (59 intraplaque hemorrhage, 63 lipid-rich necrotic core, and 47 fibrous); the average values of the intraplaque hemorrhage, lipid-rich necrotic core, and fibrous tissue were 17.475 Hounsfield units (HU) and 18.407 HU, 39.476 HU and 48.048 HU, and 91.66 HU and 93.128 HU, respectively, before and after the administration of contrast medium. The Mann-Whitney test showed a statistically significant difference of HU values both in basal and after the administration of contrast material phase. Receiver operating characteristic analysis showed a statistical association between intraplaque hemorrhage and low HU values, and a threshold of 25 HU demonstrated the presence of intraplaque hemorrhage with a sensitivity and specificity of 93.22% and 92.73%, respectively. The Wilcoxon test showed that the attenuation of the plaque before and after administration of contrast material is different (intraplaque hemorrhage, lipid-rich necrotic core, and fibrous tissue had P values of .006, .0001, and .018, respectively). CONCLUSIONS: The results of this preliminary study suggest that CT can be used to identify the presence of intraplaque hemorrhage according to the attenuation. A threshold of 25 HU in the volume acquired after the administration of contrast medium is associated with an optimal sensitivity and specificity. Special care should be given to the correct identification of the ROI. [...]



Dynamic Contrast-Enhanced MRI-Derived Intracellular Water Lifetime ({tau}i): A Prognostic Marker for Patients with Head and Neck Squamous Cell Carcinomas [HEAD & NECK]

2018-01-11T08:00:42-08:00

BACKGROUND AND PURPOSE: Shutter-speed model analysis of dynamic contrast-enhanced MR imaging allows estimation of mean intracellular water molecule lifetime (a measure of cellular energy metabolism) and volume transfer constant (a measure of hemodynamics). The purpose of this study was to investigate the prognostic utility of pretreatment mean intracellular water molecule lifetime and volume transfer constant in predicting overall survival in patients with squamous cell carcinomas of the head and neck and to stratify p16-positive patients based upon survival outcome. MATERIALS AND METHODS: A cohort of 60 patients underwent dynamic contrast-enhanced MR imaging before treatment. Median, mean intracellular water molecule lifetime and volume transfer constant values from metastatic nodes were computed from each patient. Kaplan-Meier analyses were performed to associate mean intracellular water molecule lifetime and volume transfer constant and their combination with overall survival for the first 2 years, 5 years, and beyond (median duration, >7 years). RESULTS: By the last date of observation, 18 patients had died, and median follow-up for surviving patients (n = 42) was 8.32 years. Patients with high mean intracellular water molecule lifetime (4 deaths) had significantly (P = .01) prolonged overall survival by 5 years compared with those with low mean intracellular water molecule lifetime (13 deaths). Similarly, patients with high mean intracellular water molecule lifetime (4 deaths) had significantly (P = .006) longer overall survival at long-term duration than those with low mean intracellular water molecule lifetime (14 deaths). However, volume transfer constant was a significant predictor for only the 5-year follow-up period. There was some evidence (P < .10) to suggest that mean intracellular water molecule lifetime and volume transfer constant were associated with overall survival for the first 2 years. Patients with high mean intracellular water molecule lifetime and high volume transfer constant were associated with significantly (P < .01) longer overall survival compared with other groups for all follow-up periods. In addition, p16-positive patients with high mean intracellular water molecule lifetime and high volume transfer constant demonstrated a trend toward the longest overall surviv[...]



Diffusion-Weighted Imaging of the Head and Neck: Influence of Fat-Suppression Technique and Multishot 2D Navigated Interleaved Acquisitions [HEAD & NECK]

2018-01-11T08:00:42-08:00

BACKGROUND AND PURPOSE:

DWI of the head and neck can reveal valuable information, but the effects of fat suppression and multishot acquisition on image quality have not been thoroughly investigated. We aimed to comprehensively compare the quality of head and neck DWI at 3T using 2 fat-suppression techniques, STIR, and spectral presaturation with inversion recovery, which were used with both single- and multishot EPI.

MATERIALS AND METHODS:

Sixty-five study participants underwent 3 DWI sequences of single-shot EPI–STIR, single-shot EPI–spectral presaturation with inversion recovery, and multishot EPI–spectral presaturation with inversion recovery of the head and neck. In multiple anatomic regions, 2 independent readers assessed 5-point visual scores for fat-suppression uniformity and image distortion, and 1 reader measured the contrast-to-noise ratio and ADC.

RESULTS:

The mean visual score for fat-suppression uniformity was higher in single-shot EPI–STIR than in other sequences (all regions except for the orbital region, P < .05). The mean visual score for image distortion was higher in multishot EPI–spectral presaturation with inversion recovery than in single-shot EPI sequences (all regions, P < .001). Contrast-to-noise ratio was mostly lower in single-shot EPI–STIR than in other sequences (P < .001), and ADC was significantly higher in multishot EPI–spectral presaturation with inversion recovery than in single-shot EPI sequences (P ≤ .001).

CONCLUSIONS:

Overall, multishot EPI–spectral presaturation with inversion recovery provided the best image quality, with relatively homogeneous fat suppression, less image distortion than single-shot EPI sequences, and higher contrast-to-noise ratio than single-shot EPI–STIR. The measured ADC values can be higher in multishot EPI–spectral presaturation with inversion recovery, which necessitates cautious application of the previously reported ADC values to clinical settings.




Effect of an Arm Traction Device on Image Quality and Radiation Exposure during Neck CT: A Prospective Study [HEAD & NECK]

2018-01-11T08:00:42-08:00

BACKGROUND AND PURPOSE:

The image quality of neck CT is frequently disturbed by streak artifact from the shoulder girdles. Our aim was to determine the effects of an arm traction device on image quality and radiation exposure in neck CT.

MATERIALS AND METHODS:

Patients with lymphoma with complete remission who were scheduled to undergo 2 consecutive follow-up neck CT scans for surveillance within a 1-year interval were enrolled in this prospective study. They underwent 2 consecutive neck CT scans (intervention protocol: patients with an arm traction device; standard protocol: no positioning optimization) on the same CT system. The primary outcome measures were image noise in the lower neck and dose-length product. Secondary outcomes were streak artifacts in the supraclavicular fossa, volume CT dose index, and the extent of the biacromial line shift.

RESULTS:

Seventy-three patients were enrolled and underwent 2 consecutive CT scans with a mean interval of 155 days. In the intervention protocol, a mean noise reduction in the lower neck of 25.2%–28.5% (P < .001) was achieved, and a significant decrease in dose-length product (413 versus 397, P < .001) was observed. The intervention protocol significantly decreased streak artifacts (P < .001) and volume CT dose index (13.9 versus 13.4, P < .001) and could lower the biacromial line an average of 2.1 cm.

CONCLUSIONS:

An arm traction device can improve image quality and reduce radiation exposure during neck CT. The device can be simply applied in cooperative patients with suspected lower neck lesions, and the approach offers distinct advantages over the conventional imaging protocol.




Patterns of Sonographically Detectable Echogenic Foci in Pediatric Thyroid Carcinoma with Corresponding Histopathology: An Observational Study [HEAD & NECK]

2018-01-11T08:00:42-08:00

BACKGROUND AND PURPOSE: Small echogenic foci within pediatric thyroid nodules are commonly seen by ultrasound and are one of the features used to determine the level of suspicion for malignancy. These are sometimes termed "microcalcifications," but their relation with malignancy is controversial due to the lack of standard terminology. Our aim was to evaluate sonographic patterns of echogenic foci in malignant pediatric thyroid nodules and describe the distribution of corresponding psammoma bodies and other histopathologic findings in thyroidectomy specimens. MATERIALS AND METHODS: Ultrasounds of 15 pathologically proved malignant thyroid nodules in children were retrospectively reviewed by 2 radiologists who separately classified echogenic foci into the 4 morphologic patterns described in the American College of Radiology Thyroid Imaging, Reporting and Data System and noted their presence and distribution. Interobserver agreement was assessed, and consensus was reached for nodules for which there was disagreement. Surgical pathology findings from thyroidectomy specimens were retrospectively reviewed for the presence and distribution of psammomatous and dystrophic/stromal calcifications and eosinophilic/sticky colloid. Ultrasound and histopathologic ratings were compared, and frequencies and percentages corresponding to observed agreement levels were calculated. RESULTS: Interobserver agreement between radiologists' sonographic assessments for the presence and distribution of echogenic foci ranged from 53% to 100% for all categories. Punctate echogenic foci were present in all nodules, and macrocalcifications, in 27%. Histopathology of the 15 nodules revealed that only 4 (27%) had psammomatous calcifications, while 9 (60%) had stromal calcifications and 8 (53%) had sticky colloid. CONCLUSIONS: Sonographically detectable echogenic foci in malignant pediatric thyroid nodules can be reliably classified on the basis of American College of Radiology Thyroid Imaging, Reporting and Data System, with punctate echogenic foci composing the most common subtype. These echogenic foci do not represent psammomatous calcifications most of the time; instead, more than half of the malignant thyroid nodules with echogenic foci contained stro[...]



Role of MR Neurography for the Diagnosis of Peripheral Trigeminal Nerve Injuries in Patients with Prior Molar Tooth Extraction [PERIPHERAL NERVOUS SYSTEM]

2018-01-11T08:00:42-08:00

BACKGROUND AND PURPOSE: Clinical neurosensory testing is an imperfect reference standard to evaluate molar tooth extraction related peripheral trigeminal neuropathy. The purpose was to evaluate the diagnostic accuracy of MR neurography in this domain and correlation with neurosensory testing and surgery. MATERIALS AND METHODS: In this retrospective study, nerve caliber, T2 signal intensity ratio, and contrast-to-noise ratios were recorded by 2 observers using MR neurography for bilateral branches of the peripheral trigeminal nerve, the inferior alveolar and lingual nerves. Patient demographics and correlation of the MR neurography findings with the Sunderland classification of nerve injury and intraoperative findings of surgical patients were obtained. RESULTS: Among 42 patients, the mean ± SD age for case and control patients were 35.8 ± 10.2 years and 43.2 ± 11.5 years, respectively, with male-to-female ratios of 1:1.4 and 1:5, respectively. Case subjects (peripheral trigeminal neuropathy or injury) had significantly larger differences in nerve thickness, T2 signal intensity ratio, and contrast-to-noise ratios than control patients for the inferior alveolar nerve and lingual nerve (P = .01 and .0001, .012 and .005, and .01 and .01, respectively). Receiver operating characteristic analysis showed a significant association among differences in nerve thickness, T2 signal intensity ratio, and contrast-to-noise ratios and nerve injury (area under the curve, 0.83–0.84 for the inferior alveolar nerve and 0.77–0.78 for the lingual nerve). Interobserver agreement was good for the inferior alveolar nerve (intraclass correlation coefficient, 0.70–0.79) and good to excellent for the lingual nerve (intraclass correlation coefficient, 0.75–0.85). MR neurography correlations with respect to clinical neurosensory testing and surgical classifications were moderate to good. Pearson correlation coefficients of 0.68 and 0.81 and of 0.60 and 0.77 were observed for differences in nerve thickness. CONCLUSIONS: MR neurography can be reliably used for the diagnosis of injuries to the peripheral trigeminal nerve related to molar tooth extractions, with good to excellent corr[...]



MR Imaging of the Superior Cervical Ganglion and Inferior Ganglion of the Vagus Nerve: Structures That Can Mimic Pathologic Retropharyngeal Lymph Nodes [PERIPHERAL NERVOUS SYSTEM]

2018-01-11T08:00:42-08:00

BACKGROUND AND PURPOSE: The superior cervical ganglion and inferior ganglion of the vagus nerve can mimic pathologic retropharyngeal lymph nodes. We studied the cross-sectional anatomy of the superior cervical ganglion and inferior ganglion of the vagus nerve to evaluate how they can be differentiated from the retropharyngeal lymph nodes. MATERIALS AND METHODS: This retrospective study consists of 2 parts. Cohort 1 concerned the signal intensity of routine neck MR imaging with 2D sequences, apparent diffusion coefficient, and contrast enhancement of the superior cervical ganglion compared with lymph nodes with or without metastasis in 30 patients. Cohort 2 used 3D neurography to assess the morphology and spatial relationships of the superior cervical ganglion, inferior ganglion of the vagus nerve, and the retropharyngeal lymph nodes in 50 other patients. RESULTS: All superior cervical ganglions had homogeneously greater enhancement and lower signal on diffusion-weighted imaging than lymph nodes. Apparent diffusion coefficient values of the superior cervical ganglion (1.80 ± 0.28 x 10–3mm2/s) were significantly higher than normal and metastatic lymph nodes (0.86 ± 0.10 x 10–3mm2/s, P < .001, and 0.73 ± 0.10 x 10–3mm2/s, P < .001). Ten and 13 of 60 superior cervical ganglions were hypointense on T2-weighted images and had hyperintense spots on both T1- and T2-weighted images, respectively. The latter was considered fat tissue. The largest was the superior cervical ganglion, followed in order by the retropharyngeal lymph node and the inferior ganglion of the vagus nerve (P < .001 to P = .004). The highest at vertebral level was the retropharyngeal lymph nodes, followed, in order, by the inferior ganglion of the vagus nerve and the superior cervical ganglion (P < .001 to P = .001). The retropharyngeal lymph node, superior cervical ganglion, and inferior ganglion of the vagus nerve formed a line from anteromedial to posterolateral. CONCLUSIONS: The superior cervical ganglion and the inferior ganglion of the vagus nerve can be almost always differentiated from retropharyngeal lymph nodes on MR imaging by evaluating the signa[...]



Gadolinium DTPA Enhancement Characteristics of the Rat Sciatic Nerve after Crush Injury at 4.7T [SPINE]

2018-01-11T08:00:42-08:00

BACKGROUND AND PURPOSE:

Traumatic peripheral nerve injury is common and results in loss of function and/or neuropathic pain. MR neurography is a well-established technique for evaluating peripheral nerve anatomy and pathology. However, the Gd-DTPA enhancement characteristics of acutely injured peripheral nerves have not been fully examined. This study was performed to determine whether acutely crushed rat sciatic nerves demonstrate Gd-DTPA enhancement and, if so, to evaluate whether enhancement is affected by crush severity.

MATERIALS AND METHODS:

In 26 rats, the sciatic nerve was crushed with either surgical forceps (6- to 20-N compressive force) or a microvascular/microaneurysm clip (0.1–0.6 N). Animals were longitudinally imaged at 4.7T for up to 30 days after injury. T1WI, T2WI, and T1WI with Gd-DTPA were performed.

RESULTS:

Forceps crush injury caused robust enhancement between days 3 and 21, while clip crush injury resulted in minimal-to-no enhancement. Enhancement after forceps injury peaked at 7 days and was seen a few millimeters proximal to, in the region of, and several centimeters distal to the site of crush injury. Enhancement after forceps injury was statistically significant compared with clip injury between days 3 and 7 (P < .04).

CONCLUSIONS:

Gd-DTPA enhancement of peripheral nerves may only occur above a certain crush-severity threshold. This phenomenon may explain the intermittent observation of Gd-DTPA enhancement of peripheral nerves after traumatic injury. The observation of enhancement may be useful in judging the severity of injury after nerve trauma.




Spinal Cord Gray Matter Atrophy in Amyotrophic Lateral Sclerosis [SPINE]

2018-01-11T08:00:42-08:00

BACKGROUND AND PURPOSE:

There is an emerging need for biomarkers to better categorize clinical phenotypes and predict progression in amyotrophic lateral sclerosis. This study aimed to quantify cervical spinal gray matter atrophy in amyotrophic lateral sclerosis and investigate its association with clinical disability at baseline and after 1 year.

MATERIALS AND METHODS:

Twenty-nine patients with amyotrophic lateral sclerosis and 22 healthy controls were scanned with 3T MR imaging. Standard functional scale was recorded at the time of MR imaging and after 1 year. MR imaging data were processed automatically to measure the spinal cord, gray matter, and white matter cross-sectional areas. A statistical analysis assessed the difference in cross-sectional areas between patients with amyotrophic lateral sclerosis and controls, correlations between spinal cord and gray matter atrophy to clinical disability at baseline and at 1 year, and prediction of clinical disability at 1 year.

RESULTS:

Gray matter atrophy was more sensitive to discriminate patients with amyotrophic lateral sclerosis from controls (P = .004) compared with spinal cord atrophy (P = .02). Gray matter and spinal cord cross-sectional areas showed good correlations with clinical scores at baseline (R = 0.56 for gray matter and R = 0.55 for spinal cord; P < .01). Prediction at 1 year with clinical scores (R2 = 0.54) was improved when including a combination of gray matter and white matter cross-sectional areas (R2 = 0.74).

CONCLUSIONS:

Although improvements over spinal cord cross-sectional areas were modest, this study suggests the potential use of gray matter cross-sectional areas as an MR imaging structural biomarker to monitor the evolution of amyotrophic lateral sclerosis.




Long-Term Effectiveness of Direct CT-Guided Aspiration and Fenestration of Symptomatic Lumbar Facet Synovial Cysts [SPINE]

2018-01-11T08:00:42-08:00

BACKGROUND AND PURPOSE:

Lumbar facet synovial cysts are commonly seen in facet degenerative arthropathy and may be symptomatic when narrowing the spinal canal or compressing nerve roots. The purpose of this study was to analyze the safety, effectiveness, and long-term outcomes of direct CT-guided lumbar facet synovial cyst aspiration and fenestration for symptom relief and for obviating an operation.

MATERIALS AND METHODS:

We retrospectively reviewed the medical records and imaging studies of 64 consecutive patients between 2006 and 2016 who underwent 85 CT-guided lumbar facet synovial cyst fenestration procedures in our department. We recorded patient demographics, lumbar facet synovial cyst imaging characteristics, presenting symptoms, change in symptoms after the procedure, and whether they underwent a subsequent operation. We also assessed long-term outcomes from the medical records and via follow-up telephone surveys with patients.

RESULTS:

Direct CT-guided lumbar facet synovial cyst puncture was technically successful in 98% of procedures. At first postprocedural follow-up, 86% of patients had a complete or partial symptomatic response. During a mean follow-up of 49 months, 56% of patients had partial or complete long-term relief without the need for an operation; 44% of patients underwent an operation. Patients with calcified, thick-rimmed, or low T2 signal intensity cysts were less likely to respond to the procedure and more likely to need an operation.

CONCLUSIONS:

CT-guided direct lumbar facet synovial cyst aspiration and fenestration procedures are safe, effective, and minimally invasive for symptomatic treatment of lumbar synovial facet cysts. This procedure obviates an operation in a substantial number of patients, even at long-term follow-up, and should be considered before surgical intervention.




Imaging Appearances and Pathologic Characteristics of Spinal Epidural Meningioma [SPINE]

2018-01-11T08:00:42-08:00

BACKGROUND AND PURPOSE:

Spinal epidural meningioma is an uncommon tumor. This study aimed to analyze the imaging and pathologic characteristics of this rare tumor.

MATERIALS AND METHODS:

Fourteen confirmed cases of epidural meningioma were retrospectively reviewed, and imaging characteristics and pathologic findings were analyzed to identify the typical features.

RESULTS:

The mean age of the patients (4 men, 10 women) was 44.9 years. Twelve tumors were in the cervical spinal canal, and 2, in the thoracic spinal canal. There were 9 en plaque meningiomas, 4 dumbbell-shaped meningiomas, and 1 fusiform/ovoid meningioma. The epidural meningiomas extended over 2–5 spinal segments (mean, 3.2 spinal segments). A soft epidural mass was seen in 12/14 (86%) patients. Dural calcification was seen in 8/14 (57%) tumors. Tumor caused intervertebral foramen enlargement in 10/14 (71%) patients and adhered to the nerve roots in 11/14 (79%) patients. Intradural invasion was seen in 8/14 (57%) patients. The dural tail sign was present in 13/14 (93%) tumors on contrast-enhanced T1WI. Regarding pathologic type, 10 of 14 (71%) were psammomatous, 2 of 14 (14%) were meningothelial, 1 of 14 (7%) was angiomatous, and 1 of 14 (7%) was transitional. During follow-up (mean follow-up, 73.4 months; range, 4–192 months), 7 patients had recurrence. Recurrences were between 4 and 192 months after the operation.

CONCLUSIONS:

Epidural meningioma has 3 different growth patterns. Dural thickening, calcification, invasion, and epidural mass formation are characteristic features of epidural meningioma. Regular follow-up imaging is required to detect recurrence.







Zika Virus Iceberg: Very Large [LETTERS]

2017-12-15T08:00:48-08:00







Reply: [LETTERS]

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2017-12-15T08:00:48-08:00







Pacemakers in MRI for the Neuroradiologist [review-article]

2017-12-15T08:00:48-08:00

SUMMARY:

Cardiac implantable electronic devices are frequently encountered in clinical practice in patients being screened for MR imaging examinations. Traditionally, the presence of these devices has been considered a contraindication to undergoing MR imaging. Growing evidence suggests that most of these patients can safely undergo an MR imaging examination if certain conditions are met. This document will review the relevant cardiac implantable electronic devices encountered in practice today, the background physics/technical factors related to scanning these devices, the multidisciplinary screening protocol used at our institution for scanning patients with implantable cardiac devices, and our experience in safely performing these examinations since 2010.




Setting the Stage for 2018: How the Changes in the American Joint Committee on Cancer/Union for International Cancer Control Cancer Staging Manual Eighth Edition Impact Radiologists [HEAD & NECK]

2017-12-15T08:00:48-08:00

SUMMARY:

The updated eighth edition of the Cancer Staging Manual of the American Joint Committee on Cancer will be implemented in January 2018. There are multiple changes to the head and neck section of the manual, which will be relevant to radiologists participating in multidisciplinary head and neck tumor boards and reading pretreatment head and neck cancer scans. Human papillomavirus–related/p16(+) oropharyngeal squamous cell carcinoma will now be staged separately; this change reflects the markedly better prognosis of these tumors compared with non-human papillomavirus/p16(–) oropharyngeal squamous cell carcinoma. Nodal staging has dramatically changed so that there are different tables for human papillomavirus/p16(+) oropharyngeal squamous cell carcinoma, Epstein-Barr virus–related nasopharyngeal carcinoma, and all other head and neck squamous cell carcinomas. Extranodal extension of tumor is a new clinical feature for this third staging group. In the oral cavity, the pathologically determined depth of tumor invasion is a new staging criterion, while extrinsic tongue muscle invasion is no longer part of staging. This review serves to educate radiologists on the eighth edition changes and their rationale.




Wide Variability in Prethrombectomy Workflow Practices in the United States: A Multicenter Survey [INTERVENTIONAL]

2017-12-15T08:00:48-08:00

BACKGROUND AND PURPOSE: Clinical outcomes in patients with acute ischemic stroke caused by large vessel occlusion depend on the speed and quality of workflows leading to mechanical thrombectomy. In the absence of universally accepted best practices for workflow, developing stroke hospitals can benefit from improved awareness of real-world workflows in effect at experienced centers. To this end, we surveyed prethrombectomy workflow practices at stroke centers throughout the United States. MATERIALS AND METHODS: E-mail and phone interviews were conducted with neurointerventional team members at 30 experienced, endovascular-capable stroke centers. Questions were chosen to reflect workflow components of triage, team activation, transport, case setup, and anesthesia. RESULTS: There is wide variation in prethrombectomy workflows. At 53% of institutions, nonphysician staff respond to stroke alerts alongside physicians. Imaging triage involves noninvasive angiography or perfusion imaging at 97% and 63% of institutions, respectively. Neurointerventional consultation is initiated before the completion of neuroimaging at 86% of institutions, and the team is activated before a final treatment decision at 59%. The neurointerventional team most commonly arrives within 30 minutes. Patients may be transported to the neuroangiography suite before team arrival at 43% of institutions. Procedural trays are set up in advance of team arrival at 13% of centers; additional thrombectomy devices are centrally stored at 54%. A power injector for angiographic runs is consistently used at 43% of institutions. Anesthesiology routinely supports thrombectomies at 67% of institutions. CONCLUSIONS: Prethrombectomy workflows vary widely between exp[...]



Comparison between the Prebolus T1 Measurement and the Fixed T1 Value in Dynamic Contrast-Enhanced MR Imaging for the Differentiation of True Progression from Pseudoprogression in Glioblastoma Treated with Concurrent Radiation Therapy and Temozolomide Chemotherapy [ADULT BRAIN]

2017-12-15T08:00:48-08:00

BACKGROUND AND PURPOSE: Glioblastoma is the most common primary brain malignancy and differentiation of true progression from pseudoprogression is clinically important. Our purpose was to compare the diagnostic performance of dynamic contrast-enhanced pharmacokinetic parameters using the fixed T1 and measured T1 on differentiating true from pseudoprogression of glioblastoma after chemoradiation with temozolomide. MATERIALS AND METHODS: This retrospective study included 37 patients with histopathologically confirmed glioblastoma with new enhancing lesions after temozolomide chemoradiation defined as true progression (n = 15) or pseudoprogression (n = 22). Dynamic contrast-enhanced pharmacokinetic parameters, including the volume transfer constant, the rate transfer constant, the blood plasma volume per unit volume, and the extravascular extracellular space per unit volume, were calculated by using both the fixed T1 of 1000 ms and measured T1 by using the multiple flip-angle method. Intra- and interobserver reproducibility was assessed by using the intraclass correlation coefficient. Dynamic contrast-enhanced pharmacokinetic parameters were compared between the 2 groups by using univariate and multivariate analysis. The diagnostic performance was evaluated by receiver operating characteristic analysis and leave-one-out cross validation. RESULTS: The intraclass correlation coefficients of all the parameters from both T1 values were fair to excellent (0.689–0.999). The volume transfer constant and rate transfer constant from the fixed T1 were significantly higher in patients with true progression (P = .048 and .010, respectively). Multivariate analysis revealed that the rate transfer co[...]



Initial Investigation into Microbleeds and White Matter Signal Changes following Radiotherapy for Low-Grade and Benign Brain Tumors Using Ultra-High-Field MRI Techniques [ADULT BRAIN]

2017-12-15T08:00:48-08:00

BACKGROUND AND PURPOSE: External beam radiation therapy is a common treatment for many brain neoplasms. While external beam radiation therapy adheres to dose limits to protect the uninvolved brain, areas of high dose to normal tissue still occur. Patients treated with chemoradiotherapy can have adverse effects such as microbleeds and radiation necrosis, but few studies exist of patients treated without chemotherapy. MATERIALS AND METHODS: Ten patients were treated for low-grade or benign neoplasms with external beam radiation therapy only and scanned within 12–36 months following treatment with a 7T MR imaging scanner. A multiecho gradient-echo sequence was acquired and postprocessed into SWI, quantitative susceptibility mapping, and apparent transverse relaxation maps. Six patients returned for follow-up imaging approximately 18 months following their first research scan and were imaged with the same techniques. RESULTS: At the first visit, 7/10 patients had microbleeds evident on SWI, quantitative susceptibility mapping, and apparent transverse relaxation. All microbleeds were within a dose region of >45 Gy. Additionally, 4/10 patients had asymptomatic WM signal changes evident on standard imaging. Further analysis with our technique revealed that these lesions were venocentric, suggestive of a neuroinflammatory process. CONCLUSIONS: There exists a potential for microbleeds in patients treated with external beam radiation therapy without chemotherapy. This finding is of clinical relevance because it could be a precursor of future neurovascular disease and indicates that additional care should be taken when using therapies such as anticoagulants. Addi[...]



Photon-Counting CT of the Brain: In Vivo Human Results and Image-Quality Assessment [ADULT BRAIN]

2017-12-15T08:00:48-08:00

BACKGROUND AND PURPOSE: Photon-counting detectors offer the potential for improved image quality for brain CT but have not yet been evaluated in vivo. The purpose of this study was to compare photon-counting detector CT with conventional energy-integrating detector CT for human brains. MATERIALS AND METHODS: Radiation dose–matched energy-integrating detector and photon-counting detector head CT scans were acquired with standardized protocols (tube voltage/current, 120 kV(peak)/370 mAs) in both an anthropomorphic head phantom and 21 human asymptomatic volunteers (mean age, 58.9 ± 8.5 years). Photon-counting detector thresholds were 22 and 52 keV (low-energy bin, 22–52 keV; high-energy bin, 52–120 keV). Image noise, gray matter, and white matter signal-to-noise ratios and GM–WM contrast and contrast-to-noise ratios were measured. Image quality was scored by 2 neuroradiologists blinded to the CT detector type. Reproducibility was assessed with the intraclass correlation coefficient. Energy-integrating detector and photon-counting detector CT images were compared using a paired t test and the Wilcoxon signed rank test. RESULTS: Photon-counting detector CT images received higher reader scores for GM–WM differentiation with lower image noise (all P < .001). Intrareader and interreader reproducibility was excellent (intraclass correlation coefficient, ≥0.86 and 0.79, respectively). Quantitative analysis showed 12.8%–20.6% less image noise for photon-counting detector CT. The SNR of photon-counting detector CT was 19.0%–20.0% higher than of energy-integrating detector CT for GM and WM. Th[...]



Redefining the Pulvinar Sign in Fabry Disease [ADULT BRAIN]

2017-12-15T08:00:48-08:00

BACKGROUND AND PURPOSE: The pulvinar sign refers to exclusive T1WI hyperintensity of the lateral pulvinar. Long considered a common sign of Fabry disease, the pulvinar sign has been reported in many pathologic conditions. The exact incidence of the pulvinar sign has never been tested in representative cohorts of patients with Fabry disease. The aim of this study was to assess the prevalence of the pulvinar sign in Fabry disease by analyzing T1WI in a large Fabry disease cohort, determining whether relaxometry changes could be detected in this region independent of the pulvinar sign positivity. MATERIALS AND METHODS: We retrospectively analyzed brain MR imaging of 133 patients with Fabry disease recruited through specialized care clinics. A subgroup of 26 patients underwent a scan including 2 FLASH sequences for relaxometry that were compared with MRI scans of 34 healthy controls. RESULTS: The pulvinar sign was detected in 4 of 133 patients with Fabry disease (3.0%). These 4 subjects were all adult men (4 of 53, 7.5% of the entire male population) with renal failure and under enzyme replacement therapy. When we tested for discrepancies between Fabry disease and healthy controls in quantitative susceptibility mapping and relaxometry maps, no significant difference emerged for any of the tested variables. CONCLUSIONS: The pulvinar sign has a significantly lower incidence in Fabry disease than previously described. This finding, coupled with a lack of significant differences in quantitative MR imaging, allows hypothesizing that selective involvement of the pulvinar is a rare neuroradiologic sign of Fabry diseas[...]



Correlation between Clinical Outcomes and Baseline CT and CT Angiographic Findings in the SWIFT PRIME Trial [ADULT BRAIN]

2017-12-15T08:00:48-08:00

BACKGROUND AND PURPOSE: Patient selection for endovascular therapy remains a great challenge in clinic practice. We sought to determine the effect of baseline CT and angiography on outcomes in the Solitaire With the Intention for Thrombectomy as Primary Endovascular Treatment for Acute Ischemic Stroke (SWIFT PRIME) trial and to identify patients who would benefit from endovascular stroke therapy. MATERIALS AND METHODS: The primary end point was a 90-day modified Rankin Scale score of 0–2. Subgroup and classification and regression tree analysis was performed on baseline ASPECTS, site of occlusion, clot length, collateral status, and onset-to-treatment time. RESULTS: Smaller baseline infarct (n = 145) (ASPECTS 8–10) was associated with better outcomes in patients treated with thrombectomy versus IV tPA alone (66% versus 41%; rate ratio, 1.62) compared with patients with larger baseline infarcts (n = 44) (ASPECTS 6–7) (42% versus 21%; rate ratio, 1.98). The benefit of thrombectomy over IV tPA alone did not differ significantly by ASPECTS. Stratification by occlusion location also showed benefit with thrombectomy across all groups. Improved outcomes after thrombectomy occurred in patients with clot lengths of ≥8 mm (71% versus 43%; rate ratio, 1.67). Outcomes stratified by collateral status had a benefit with thrombectomy across all groups: none–fair collaterals (33% versus 0%), good collaterals (58% versus 44%), and excellent collaterals (82% versus 28%). Using a 3-level classification and regression tree analysis, we observed optimal outcomes in patients w[...]



Necessary Catheter Diameters for Mechanical Thrombectomy with ADAPT [INTERVENTIONAL]

2017-12-15T08:00:48-08:00

BACKGROUND AND PURPOSE: Large-bore catheters allow mechanical thrombectomy in ischemic stroke by engaging and retrieving clots without additional devices (direct aspiration first-pass technique [ADAPT]). The purpose of this study was to establish a model for minimal catheter diameters needed for ADAPT. MATERIALS AND METHODS: We established a theoretic model for the calculation of minimal catheter diameters needed for ADAPT. We then verified its validity in 28 ADAPT maneuvers in a porcine in vivo model. To account for different mechanical thrombectomy techniques, we factored in ADAPT with/without a hypothetic 0.021-inch microcatheter or 0.014-inch microwire inside the lumen of the aspiration catheter and aspiration with a 60-mL syringe versus an aspiration pump. RESULTS: According to our calculations, catheters with an inner diameter of >0.040 inch and >0.064 inch, respectively, are needed to be effective in the middle cerebral artery (2.5-mm diameter) or in the internal carotid artery (4 mm) in an average patient. There was a significant correlation between predicted and actual thrombectomy results (P = .010). Our theoretic model had a positive and negative predictive value of 78% and 79%, respectively. Sensitivity and specificity were 88% and 64%, respectively. CONCLUSIONS: Our theoretic model allows estimating the minimal catheter diameters needed for successful mechanical thrombectomy with ADAPT, as demonstrated by the good agreement with our animal experiments. Our model will be helpful to interventionalists in avoiding selecting catheters tha[...]



WEB Treatment of Ruptured Intracranial Aneurysms: A Single-Center Cohort of 100 Patients [INTERVENTIONAL]

2017-12-15T08:00:48-08:00

BACKGROUND AND PURPOSE: The Woven EndoBridge device was recently introduced for the intrasaccular treatment of wide-neck aneurysms without the need for adjunctive devices. We present our results of the primary treatment of ruptured aneurysms with the Woven EndoBridge regardless of location or neck size. MATERIALS AND METHODS: Between February 2015 and April 2017, 100 ruptured aneurysms were selectively treated with the Woven EndoBridge. No supporting stents or balloons were used. There were 71 women treated (mean patient age, 59 years; median age, 60 years; range, 23–82 years). RESULTS: The mean aneurysm size was 5.6 mm (range, 3–13 mm), and 42 aneurysms were ≤4 mm. Sixty-six aneurysms (66%) had a wide neck, defined as ≥4 mm or a dome-neck ratio ≤1.5. There was 1 procedural rupture without sequelae. In 9 patients (9%), thromboembolic complications occurred. One poor grade patient died; neurologic deficits remained in 3. Overall treatment-related morbidity-mortality was 4% (4 of 100; 95% CI, 1.2%–10.2%). Two of 100 aneurysms were initially incompletely occluded and were additionally treated early after initial intervention. Of 80 eligible patients, 74 (93%) had 3-month angiographic follow-up. Fifty-four aneurysms (73%) were completely occluded, 17 (23%) had a small neck remnant, and 3 (4%) were incompletely occluded. One patient was additionally treated with a second Woven EndoBridge, and in 2 patients, additional treatment is scheduled. The overall reopening/retreatment rate was 6.8% (5 of 74; 95% CI,[...]






Treatment of Middle Cerebral Artery Aneurysms with Flow-Diverter Stents: A Systematic Review and Meta-Analysis [INTERVENTIONAL]

2017-12-15T08:00:48-08:00

BACKGROUND: The safety and efficacy of flow-diversion treatment of MCA aneurysms have not been well-established. PURPOSE: Our aim was to evaluate angiographic and clinical outcomes after flow diversions for MCA aneurysms. DATA SOURCES: A systematic search of PubMed, MEDLINE, and Embase was performed for studies published from 2008 to May 2017. STUDY SELECTION: According to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we selected studies with >5 patients describing angiographic and clinical outcomes after flow-diversion treatment of MCA aneurysms. DATA ANALYSIS: Random-effects meta-analysis was used to pool the following outcomes: aneurysm occlusion rate, procedure-related complications, rupture rate of treated aneurysms, and occlusion of the jailed branches. DATA SYNTHESIS: Twelve studies evaluating 244 MCA aneurysms were included in this meta-analysis. Complete/near-complete occlusion was obtained in 78.7% (95% CI, 67.8%–89.7%) of aneurysms. The rupture rate of treated aneurysms during follow-up was 0.4% per aneurysm-year. The rate of treatment-related complications was 20.7% (95% CI, 14%–27.5%), and approximately 10% of complications were permanent. The mortality rate was close to 2%. Nearly 10% (95% CI, 4.7%–15.5%) of jailed arteries were occluded during follow-up, whereas 26% (95% CI, 14.4%–37.6%) had slow flow. Rates of symptoms related to occlusion and slow flow were close to 5%. LIMITATIONS: Small and r[...]



Predictors of Incomplete Occlusion following Pipeline Embolization of Intracranial Aneurysms: Is It Less Effective in Older Patients? [INTERVENTIONAL]

2017-12-15T08:00:48-08:00

BACKGROUND AND PURPOSE: Flow diversion with the Pipeline Embolization Device (PED) for the treatment of intracranial aneurysms is associated with a high rate of aneurysm occlusion. However, clinical and radiographic predictors of incomplete aneurysm occlusion are poorly defined. In this study, predictors of incomplete occlusion at last angiographic follow-up after PED treatment were assessed. MATERIALS AND METHODS: A retrospective analysis of consecutive aneurysms treated with the PED between 2009 and 2016, at 3 academic institutions in the United States, was performed. Cases with angiographic follow-up were selected to evaluate factors predictive of incomplete aneurysm occlusion at last follow-up. RESULTS: We identified 465 aneurysms treated with the PED; 380 (81.7%) aneurysms (329 procedures; median age, 58 years; female/male ratio, 4.8:1) had angiographic follow-up, and were included. Complete occlusion (100%) was achieved in 78.2% of aneurysms. Near-complete (90%–99%) and partial (<90%) occlusion were collectively achieved in 21.8% of aneurysms and defined as incomplete occlusion. Of aneurysms followed for at least 12 months (211 of 380), complete occlusion was achieved in 83.9%. Older age (older than 70 years), nonsmoking status, aneurysm location within the posterior communicating artery or posterior circulation, greater aneurysm maximal diameter (≥21 mm), and shorter follow-up time (<12 months) were significantly associated w[...]



Hemodynamic Characteristics of Ruptured and Unruptured Multiple Aneurysms at Mirror and Ipsilateral Locations [INTERVENTIONAL]

2017-12-15T08:00:48-08:00

BACKGROUND AND PURPOSE: Different hemodynamic patterns have been associated with aneurysm rupture. The objective was to test whether hemodynamic characteristics of the ruptured aneurysm in patients with multiple aneurysms were different from those in unruptured aneurysms in the same patient. MATERIALS AND METHODS: Twenty-four mirror and 58 ipsilateral multiple aneurysms with 1 ruptured and the others unruptured were studied. Computational fluid dynamics models were created from 3D angiographies. Case-control studies of mirror and ipsilateral aneurysms were performed with paired Wilcoxon tests. RESULTS: In mirror pairs, the ruptured aneurysm had more oscillatory wall shear stress (P = .007) than the unruptured one and tended to be more elongated (higher aspect ratio), though this trend achieved only marginal significance (P = .03, 1-sided test). In ipsilateral aneurysms, ruptured aneurysms had larger maximum wall shear (P = .05), more concentrated (P < .001) and oscillatory wall shear stress (P < .001), stronger (P < .001) and more concentrated inflow jets (P < .001), larger maximum velocity (P < .001), and more complex flow patterns (P < .001) compared with unruptured aneurysms. Additionally, ruptured aneurysms were larger (P < .001) and more elongated (P < .001) and had wider necks (P < .001) and lower minimum wall shear stress (P < .001) than unruptured aneurysms. CONCLUSIONS: High wall s[...]



Endovascular Treatment of Vein of Galen Malformations: A Systematic Review and Meta-Analysis [PEDIATRICS]

2017-12-15T08:00:48-08:00

BACKGROUND: Outcomes after endovascular embolization of vein of Galen malformations remain relatively poorly described. PURPOSE: We performed a systematic review of the literature to determine outcomes and predictors of good outcomes following endovascular treatment of vein of Galen malformations. DATA SOURCES: We used Ovid MEDLINE, Ovid Embase, and the Web of Science. STUDY SELECTION: Our study consisted of all case series with ≥4 patients receiving endovascular treatment of vein of Galen malformations published through January 2017. DATA ANALYSIS: We studied the following outcomes: complete/near-complete occlusion rates, technical complications, perioperative stroke, perioperative hemorrhage, technical mortality, all-cause mortality, poor neurologic outcomes, and good neurologic outcomes. Outcomes were stratified by age-group (neonate, infant, child). A random-effects meta-analysis was performed. DATA SYNTHESIS: A total of 27 series with 578 patients were included; 41.9% of patients were neonates, 45.0% of patients were infants, and 13.1% of patients were children. All-cause mortality was 14.0% (95% CI, 8.0%–22.0%). Overall good neurologic outcome rates were 62.0% (95% CI, 57.0%–67.0%). Overall poor neurologic outcome rates were 21.0% (95% CI, 17.0%–26.0%). Neonates were significantly less likely to have good neurologic outcomes than infants (48.0%; 95% CI, 35.0%&ndas[...]



Pial Artery Supply as an Anatomic Risk Factor for Ischemic Stroke in the Treatment of Intracranial Dural Arteriovenous Fistulas [INTERVENTIONAL]

2017-12-15T08:00:48-08:00

BACKGROUND AND PURPOSE: Although intracranial dural arteriovenous fistulas are principally supplied by dural branches of the external carotid, internal carotid, and vertebral arteries, they can also be fed by pial arteries that supply the brain. We sought to determine the frequency of neurologic deficits following treatment of intracranial dural arteriovenous fistulas with and without pial artery supply. MATERIALS AND METHODS: One hundred twenty-two consecutive patients who underwent treatment for intracranial dural arteriovenous fistulas at our hospital from 2008 to 2015 were retrospectively reviewed. Patient data were examined for posttreatment neurologic deficits; patients with such deficits were evaluated for imaging evidence of cerebral infarction. Data were analyzed with multivariable logistic regression. RESULTS: Of 122 treated patients, 29 (23.8%) had dural arteriovenous fistulas with pial artery supply and 93 (76.2%) had dural arteriovenous fistulas without pial arterial supply. Of patients with pial artery supply, 4 (13.8%) had posttreatment neurologic deficits, compared with 2 patients (2.2%) without pial artery supply (P = .04). Imaging confirmed that 3 patients with pial artery supply (10.3%) had cerebral infarcts, compared with only 1 patient without pial artery supply (1.1%, P = .03). Increasing patient age was also positively associated with pial supp[...]