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Background: For cardiac arrest survivors who are initially comatose after restoration of spontaneous circulation, the extent of brain injury and expected recovery are crucial for management decisions. Advanced diffusion imaging approaches may provide additional insight into microstructural integrity and potential for arousal recovery (AR). Methods: Multi-shell diffusion imaging was acquired in a prospective study. Neurite orientation dispersion (OD), intracellular volume fraction (ICVF), free water fraction (ISO), mean kurtosis (MK), axial kurtosis (AK), radial kurtosis (RK), mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD) and fractional anisotropy (FA) were calculated (see Figure). Median whole-brain values in patients with AR by discharge were compared with those with no AR and to controls (ANOVA, post-hoc 2-tailed Wilcoxon test). Multivariable backward stepwise logistic regression was performed to predict AR. Results: 19 patients (mean ±SD 48±23 y, 42% men) and 5 controls (37±19 y, 40% men) were analyzed (10 patients with AR, 9 without). Median [IQR] time-to-MRI was 5 [4-8] days. Patients with no AR had higher AK (P=0.037), and RK (P=.045) than those with AR. Controls exhibited higher FA than either AR (P=.009) or no AR (P=.02), lower MK than no AR (P=.02), lower AK than no AR (P=.02), lower RK than no AR (P=0.02), lower OD than no AR (P=.008), and lower ICVF than no AR (P=.046). AK (P=.049) and ICVF (P=.01) were found in multivariable regression to be significant predictors of AR with 81% area under the receiver operating curve (AUC). Discussion: Advanced diffusion imaging metrics, AK and ICVF, were able to predict which patients were likely to regain consciousness, with 81% AUC. Despite the small sample size, we note statistically significant differences using more sensitive measures of microstructural injury compared to more commonly used diffusivity metrics. Further investigation of advanced diffusion imaging methods is warranted.

BACKGROUND AND PURPOSE: SWI is valuable for characterization of intracranial hemorrhage and mineralization but has long acquisition times. We compared a highly accelerated wave–controlled aliasing in parallel imaging (CAIPI) SWI sequence with 2 commonly used alternatives, standard SWI and T2*-weighted gradient recalled-echo (T2*W GRE), for routine clinical brain imaging at 3T. MATERIALS AND METHODS: A total of 246 consecutive adult patients were prospectively evaluated using a conventional SWI or T2*W GRE sequence and an optimized wave–CAIPI SWI sequence, which was 3–5 times faster than the standard sequence. Two blinded radiologists scored each sequence for the presence of hemorrhage, the number of microhemorrhages, and severity of motion artifacts. Wave–CAIPI SWI was then evaluated in head-to-head comparison with the conventional sequences for visualization of pathology, artifacts, and overall diagnostic quality. Forced-choice comparisons were used for all scores. Wave–CAIPI SWI was tested for superiority relative to T2*W GRE and for noninferiority relative to standard SWI using a 15% noninferiority margin. RESULTS: Compared with T2*W GRE, wave–CAIPI SWI detected hemorrhages in more cases (P

Various imaging techniques play a role in the diagnosis of CNS vasculopathies, which comprise a heterogeneous group of disorders, including various noninflammatory and inflammatory etiologies. Noninflammatory vasculopathies include entities such as CADASIL, Susac, moyamoya, fibromuscular dysplasia, vasculopathy of connective tissue disorders, and reversible vasoconstriction syndrome. Inflammatory vasculopathies include vasculitides of different vessel sizes, primary angiitis of the CNS, vasculitis of systemic disease, and vasculitis secondary to specific causes. Miscellaneous etiology includes cerebral amyloid angiopathy, which has noninflammatory and inflammatory subtypes. This article discusses important clinical and imaging findings used to distinguish these disorders.

Academic radiologists spend considerable amounts of time and effort providing nonclinical value-added services in the realms of teaching, research, and administration that are not reimbursable through traditional relative value units (RVUs) under the resource-based relative value scale. Numerous systems of academic RVUs have been proposed by medicine, surgery, and radiology programs to measure and reward these nonclinical contributions. In this article the authors (1) describe the traditional clinical RVU model of reimbursement; (2) review attempts to develop academic compensation models targeted toward research, teaching, and administration; and (3) describe possible models for academic productivity compensation.

A 32-year-old man was admitted to this hospital after being found in an unresponsive state in his jail cell. He had jaundice and encephalopathy; results of liver-function tests were abnormal, and CT revealed cerebral edema. Diagnostic tests were performed.

BACKGROUND AND PURPOSE To compare an ultrafast brain magnetic resonance imaging (MRI) protocol to the conventional protocol in motion-prone inpatient clinical settings. METHODS This retrospective study was HIPAA compliant and approved by the Institutional Review Board with waived inform consent. Fifty-nine inpatients (30 males, 29 females; mean age 55.1, range 23–93 years)who underwent 3-Tesla brain MRI using ultrafast and conventional protocols, both including five sequences, were included in the study. The total scan time for five ultrafast sequences was 4 minutes 59 seconds. The ideal conventional acquisition time was 10 minutes 32 seconds but the actual acquisition took 15–20 minutes. The average scan times for ultrafast localizers, T1-weighted, T2-weighted, fluid-attenuated inversion recovery (FLAIR), diffusion-weighted, T2*-weighted sequences were 14, 41, 62, 96, 80, 6 seconds, respectively. Two blinded neuroradiologists independently assessed three aspects: (1) image quality, (2) gray-white matter (GM-WM) differentiation, and (3) diagnostic concordance for the detection of six clinically relevant imaging findings. Wilcoxon signed-rank test was used to compare image quality and GM-WM scores. Interobserver reproducibility was calculated. RESULTS The ultrafast T1-weighted sequence demonstrated significantly better image quality (P = .005) and GM-WM differentiation (P 85%) between both protocols for the detection of mass-like lesion, hemorrhage, diffusion restriction, WM FLAIR hyperintensities, subarachnoid FLAIR hyperintensities, and hydrocephalus. CONCLUSIONS The ultrafast protocol achieved at least comparable image quality and high diagnostic concordance compared to the conventional protocol. This fast protocol can be a viable option to replace the conventional protocol in motion-prone inpatient clinical settings.

BACKGROUND AND PURPOSE Isolated lesions of the medulla oblongata are difficult to diagnose due to their rarity and high biopsy risk. Several individual case reports have been published, but a systematic descriptive study is lacking. Our study has three objectives that 1) provide a differential diagnosis, 2) describe magnetic resonance imaging (MRI) findings, and 3) propose a stepwise MRI-based approach to the isolated lesions of the medulla oblongata in nonstroke patients. METHODS We performed an institutional Review Board–approved retrospective analysis of 34 consecutive cases of isolated medullary lesions from nonstroke causes identified from our imaging database between January 2000 and May 2015. Eleven were excluded due to lack of pretreatment or follow-up MRI. MR studies were reviewed by two blinded neuroradiologists. The diagnosis, demographic data, and MR findings were reported using frequencies and proportions. An MRI-based diagnostic algorithm was proposed. RESULTS Most lesions were neoplasms (47%), followed by vascular malformations (15%), demyelinating/inflammatory lesions (15%), others (12%), unknown (8%), and infection (3%). Five MRI patterns were identified: 1) cystic lesion, 2) exophytic noncystic lesion, 3) intrinsic lesion with T2 hypointensity, 4) enhancing intrinsic lesion, and 5) nonenhancing intrinsic lesion. All showing patterns 1 and 2 were neoplasms or cysts. All showing pattern 3 were vascular malformations. Patterns 4 and 5 comprised of multiple etiologies. CONCLUSIONS Neoplasms are the most common cause of isolated medullary lesions in nonstroke patients. Other differential diagnoses include vascular malformations, demyelinating/inflammatory lesions, and infections. A stepwise MRI-based approach can help differentiate between various etiologies.

We hypothesized that vessel wall MR imaging (VWI) with 3D-time-of-flight magnetic resonance imaging (3D-TOF-MRA) together increases the ability to detect abnormal intracranial vessel segments compared to 3D-TOF-MRA alone.Ninety-three consecutive subjects with a clinical history of suspected vasculopathy imaged with both VWI and 3D-TOF-MRAs were retrospectively reviewed. The 3D-TOF-MRAs were reviewed by two independent neuroradiologists classifying arterial segments as normal or abnormal based on caliber changes. Following a 2-week wash-out period, the 3D-TOF-MRAs with VWI together were re-evaluated for caliber changes and/or vessel wall enhancement. A third neuroradiologist served as consensus. Significance was assessed by McNemar's test.Forty-two subjects with VWI and 3D-TOF-MRAs met the inclusion criteria. By 3D-TOF-MRA alone, 12.3% (95% confidence interval [CI], 10.7-15.1) of the arterial segments were identified as abnormal compared to 20.8% (95% CI, 18.2-23.4) by VWI and 3D-TOF-MRA together (P .0001).3D-TOF-MRA and VWI together identifies a higher number of abnormal vessel segments than 3D-TOF-MRA alone and may provide a more accurate assessment of disease burden.

Acute stroke caused by large vessel occlusions (LVOs) are common. The time window to treat is up to 24 hours, and the most important factor is the size of the ischemic core. If the core is small (

Vessel wall MR imaging (VWI) may be able to highlight vulnerable intracranial atherosclerosis with vessel wall enhancement thereby serving as a biomarker for symptomatic prestenotic intracranial atherosclerotic disease. We present a case of intracranial hemorrhage presumably due to intracranial atherosclerotic disease (ICAD) identified by VWI and silent on lumen-based imaging modalities. A 66-year-old female presented with sudden onset headache and dysarthria. A head CT showed intracranial hemorrhage centered in the right basal ganglia. Further imaging by CT angiography, MR angiography and a conventional catheter angiogram were negative. MRI of the brain, including VWI, showed abnormal enhancement in the right middle cerebral artery vessel wall, suggesting intracranial atherosclerotic changes in a prestenotic vessel. As a potential noninvasive screening test, VWI could impact patients with ICAD and become part of a stroke risk stratification algorithm.

Chronic white matter structural injury is a risk factor for poor long-term outcomes after acute ischemic stroke (AIS). However, it is unclear how white matter structural injury predisposes to poor outcomes after AIS. To explore this question, in 42 AIS patients with moderate to severe white matter hyperintensity (WMH) burden, we characterized WMH and normal-appearing white matter (NAWM) diffusivity anisotropy metrics in the hemisphere contralateral to acute ischemia in relation to ischemic tissue and early functional outcomes. All patients underwent brain MRI with dynamic susceptibility contrast perfusion and diffusion tensor imaging within 12 h and at day 3–5 post stroke. Early neurological outcomes were measured as the change in NIH Stroke Scale score from admission to day 3–5 post stroke. Target mismatch profile, percent mismatch lost, infarct growth, and rates of good perfusion were measured to assess ischemic tissue outcomes. NAWM mean diffusivity was significantly lower in the group with early neurological improvement (ENI, 0.79 vs. 0.82 × 10−3, mm2/s; P = 0.02). In multivariable logistic regression, NAWM mean diffusivity was an independent radiographic predictor of ENI (β = − 17.6, P = 0.037). Median infarct growth was 118% (IQR 26.8–221.9%) despite good reperfusion being observed in 65.6% of the cohort. NAWM and WMH diffusivity metrics were not associated with target mismatch profile, percent mismatch lost, or infarct growth. Our results suggest that, in AIS patients, white matter structural integrity is associated with poor early neurological outcomes independent of ischemic tissue outcomes.

A Man with Grandiosity, Impulsivity, and Decreased Sleep A 61-year-old man with a history of stroke and alcohol-use disorder presented with grandiosity, impulsivity, and decreased sleep. An evaluat...

A Man with Confusion after Stem-Cell Transplantation A 63-year-old man presented with confusion and weakness 5 months after he had undergone allogeneic stem-cell transplantation for chronic lymphocytic leukemia. MRI did not show evidence of acute brain abnormalities. Diagnostic tests were performed.

Background: Alterations to microstructural integrity in white matter hyperintensities (WMH) in patients with severe leukoaraiosis are poorly understood. Neurite density and orientation dispersion imaging (NODDI) produce better estimates of myelin density than diffusion tensor MRI (DTI) and therefore may provide additional in vivo insight into WMH pathophysiology. Methods: NODDI was acquired in a prospective study of acute ischemic stroke patients with advanced white matter disease (N=36). Neurite density (ND), and orientation dispersion (OD) were calculated along with model-free diffusion parameters: mean kurtosis (MK), axial kurtosis (AK), radial kurtosis (RK), mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD) and fractional anisotropy (FA). Median values were measured in in the hemisphere contralateral to the incident stroke in regions of WMH and in normal appearing white matter (NAWM) and compared (paired Wilcoxon-exact test). Linear regression was performed to evaluate univariate predictors of log-transformed WMH volumes (log WMHv). Results: Patient characteristics were: mean±SD age 69±10 y, time-to-MRI 2.8±1.2 days, median [IQ] normalized WMHv 4.7 [2.3-9.3] and 61% men. MD, AD and RD were greater, while FA, MK, AK, RK, OD and ND were lower in WMH compared to NAWM (P Discussion: Diffusivity, kurtosis and ND and OD in acute stroke patients with moderate to severe leuokoaraiosis differed significantly between NAWM and WMH in the contralateral hemisphere. Reduced neurite density is suggestive of microstructural injury. Reduced OD is typically associated with greater organization, but might also reflect restricted extracellular space diffusivity. The association of MD, AD, AK and OD in NAWM with WMH burden suggests there is ongoing risk for developing future WMH.

Background: For cardiac arrest survivors initially comatose after restoration of spontaneous circulation (ROSC), the extent of brain injury and expected neurologic outcome are crucial for patient management decisions. Advanced diffusion imaging approaches such as neurite orientation dispersion and density imaging (NODDI) or diffusion kurtosis imaging may provide additional insight into tissue integrity and potential for recovery of consciousness complementary to standard diffusion tensor imaging (DTI). Methods: Multi-shell diffusion imaging was acquired in a prospective study of comatose cardiac arrest patients and in 5 controls. Neurite orientation dispersion (OD), intracellular volume fraction (ICVF), mean kurtosis (MK), axial kurtosis (AK), radial kurtosis (RK), mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD) and fractional anisotropy (FA) were calculated. Median whole-brain values in patients with poor outcomes (no arousal recovery [AR] by discharge) were compared with those with AR and to controls (1-way ANOVA, post-hoc 1-sided Wilcoxon exact test). Results: 18 patients (mean ±SD 48±23 y, 39% men) and 5 controls (37±19 y, 40% men) were analyzed. Median (range) Glasgow Coma Scale was 3 [3-5]. 10 patients exhibited AR, 8 did not. Median [IQR] time-to-MRI was 5 [4-8] days. FA (P=0.009), MK (P=0.017), AK (P=0.026), RK (P=0.014), OD (P=0.018) and ICVF (P=0.0038) were significantly different (see Figure). FA control values were greater than AR and no AR (P Discussion: This is the first report investigating early NODDI and diffusional heterogeneity changes in post-cardiac arrest comatose patients. Patients who failed to recover arousal demonstrated greater values for all kurtosis and NODDI metrics compared to controls. Potential bias from early withdrawal of life sustaining treatment and small cohorts are limitations.

Background: Advanced diffusion imaging approaches that model intracellular and extracellular diffusion components such as neurite orientation dispersion and density imaging (NODDI) may provide additional insight into evolution of acute ischemic stroke (AIS) injury over standard diffusion tensor imaging approaches (DTI). Methods: NODDI was acquired at discharge in a prospective study of acute ischemic stroke patients with advanced white matter disease (N=36). Neurite density (ND), and orientation dispersion (OD) were calculated along with model-free diffusion parameters: mean kurtosis (MK), axial kurtosis (AK), radial kurtosis (RK), mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD) and fractional anisotropy (FA). Follow-up (FU) infarct volumes were drawn on discharge FLAIR. MD, AD, RD, FA, MK, AK, RK, OD and ND values were compared (1-way ANOVA) in infarct core (abnormal acute DWI), Growth (normal acute DWI, abnormal FU) and normal contralateral gray matter (nGM) and white matter (nWM). Results: Patient characteristics were: mean±SD age 69±10 y, median [IQR] initial NIH SS score 6 [3-11], time-to-acute MRI 7.3±5.3 h, time-to-FU MRI 2.8±1.2 days, acute DWI lesion 3.1 [0.5-18.8] cm 3 , FU lesion 8.1 [1.2-45.4] cm 3 and 61% men. Figure A shows examples of maps from a single subject. Core and growth values differed significantly (P Discussion: Increased OD is expected with tissue infarction due to loss of structural integrity. In contrast, increased ND in the subacute time-frame is paradoxical. One possible mechanism could be that hyperacute ischemia-induced cellular swelling increases tortuosity of water diffusion paths, imposing direction-dependent restrictions upon diffusion, increasing intracellular and extracellular diffusion.

Neuroimaging plays a key role in the initial work-up of patients with symptoms of acute stroke. Understanding the advantages and limitations of available CT and MR imaging techniques and how to use them optimally in the emergency setting is crucial for accurately making the diagnosis of acute stroke and for rapidly determining appropriate treatment.

Peer review of scientific articles submitted for publication has been such an integral component of innovation in science and medicine that participants (be they readers, reviewers, or editors) seldom consider its complexity. Not surprisingly, much has been written about scientific peer review. The aim of this report is to share some of the elements of that discourse with readers of the Journal of NeuroInterventional Surgery (JNIS).

Background and Purpose— Diffusion-weighted imaging (DWI) can reliably identify critically ischemic tissue shortly after stroke onset. We tested whether thresholded computed tomographic cerebral blood flow (CT-CBF) and CT-cerebral blood volume (CT-CBV) maps are sufficiently accurate to substitute for DWI for estimating the critically ischemic tissue volume. Methods— Ischemic volumes of 55 patients with acute anterior circulation stroke were assessed on DWI by visual segmentation and on CT-CBF and CT-CBV with segmentation using 15% and 30% thresholds, respectively. The contrast:noise ratios of ischemic regions on the DWI and CT perfusion (CTP) images were measured. Correlation and Bland–Altman analyses were used to assess the reliability of CTP. Results— Mean contrast:noise ratios for DWI, CT-CBF, and CT-CBV were 4.3, 0.9, and 0.4, respectively. CTP and DWI lesion volumes were highly correlated ( R 2 =0.87 for CT-CBF; R 2 =0.83 for CT-CBV; P Conclusions— The poor contrast:noise ratios of CT-CBV and CT-CBF compared with those of DWI result in large measurement error, making it problematic to substitute CTP for DWI in selecting individual acute stroke patients for treatment. CTP could be used for treatment studies of patient groups, but the number of patients needed to identify a significant effect is much higher than the number needed if DWI is used.

Triage of posterior circulation stroke from emergent large-vessel occlusion (pc-ELVO) is challenging owing to the stuttering clinical course and potential for rapid decline. Growing clinical data support the use of mechanical thrombectomy in pc-ELVO, but there are limited data addressing the clinical and imaging criteria for patient selection. We present our triage algorithm used to select patients for endovascular therapy (EVT) in the setting of pc-ELVOS. We use a consecutive retrospective database from 2004 to 2016 to describe the practice patterns and prognostic factors for pc-ELVO patients treated using both medical and EVT. Patients with moderate to severe deficits (NIHSS > 10) did better when they received EVT ( p 10), most of whom subsequently received EVT (9 of 12), with 56% favorable outcomes. Cerebellar and brainstem infarct volumes were independent imaging predictors of outcome. These results can be used to define triage criteria for use of EVT in pc-ELVO in future practice and clinical trials.

Introduction and Hypothesis: Small initial DWI lesion volume (≤70 mL) is a strong predictor of favorable outcome post i IA thrombectomy and has been used for patient selection in multiple clinical trials. We sought to investigate if collateral and/or CT ASPECT scores could predict a small DWI lesion volume. Methods: We included 130 consecutive patients with CTA showing ICA and/or proximal MCA occlusions who underwent DWI within 8 hours of stroke onset. DWI lesion volumes were dichotomized to small (≤70mL) and large (>70ml). Collateral vessels were categorized to 5 groups: 0=none, 1=minimal, 2=less than 50%, 3=more than 50%, 4=equal and 5=more than the contralateral side. Logistic regression, ROC curve analyses and weighted Kappa test were performed. Results: In 130 patients, 62 female (48%), the average values (mean±SD) were: age 70±17 years, NIHSS 16±6, DWI volume 59±65 mL, time after stroke onset 4.4±1.8 hours, CT ASPECT score 6±2 and collateral score 3±1. Time, age, gender, or occlusion site (ICA vs MCA) were not independent predictors of a small DWI volume with p values all >0.05. Collateral score (OR 6.32, P Conclusion: Collateral score alone or combined with ASPECTS can predict a small DWI lesion volume with high specificity. However, sensitivity is relatively low and inter-rater agreement is fair. These findings should be considered when DWI is not available to select patients for IA therapy.

Introduction and Hypothesis: Multiple studies have demonstrated no statistically significant association between time after stroke onset and initial infarct volume. Factors other than time may play a role in infarct growth. We sought to investigate association between collateral status and infarct growth rate in acute ischemic stroke (AIS) patients. Methods: We included 130 consecutive patients with CTA showing ICA and/or proximal MCA occlusions who had DWI within 8 hours of stroke onset. Collateral status was categorized into three groups: poor (none or minimal), intermediate (present but < contralateral side) and good (≥ contralateral side). DWI lesion volumes were measured and infarct growth rate was calculated using MRI time after stroke onset. Mann-Whitney test and correlation coefficient were used for statistical analysis. Results: In our 130 patients, 62 female (48%), the average values (mean±SD) were: age 70 ± 17 years, NIHSS 16 ± 6, DWI volume 59 ± 65 mL, time after stroke onset 4 ± 2 hours, and infarct growth rate 17 ± 23 mL/hour. 19 (14.6%) had poor, 75 (57.7%) had intermediate, and 36 (27.7%) had good collaterals. Infarct growth rate and DWI lesion volume were significantly increased with decreased collateral quality (p Conclusion: AIS patients with good collaterals have small initial DWI lesion volumes and slower infarct growth rates. These patients may be candidates for treatment options outside traditional time windows.

Background: In acute ischemic stroke (AIS), therapeutic decisions are increasingly being based upon the volume of likely-unsalvageable brain tissue, which is often estimated using DWI. Deep learning algorithms, e.g. convolutional neural networks (CNN), have been employed for chronic stroke lesion segmentation. Here we investigate the applicability of CNN for DWI lesion measurement in acute stroke. Methods: 50 AIS patients underwent DWI < 12h from last known well. Apparent diffusion coefficient maps, T2WI, and DWI were used as covariates in a 2D CNN (5-fold cross validation). Including convolutional, inception and fully connected dense layers, a CNN of 15 layers was trained using manually outlined DWI lesions. To avoid overfitting, statistical dropout, L1- and L2-regularization and batch-normalization were used. Automatically segmented lesion volumes (ALV) using a 50% risk threshold were compared to the manual lesion volumes (MLV) using Dice similarity index (DSI, a measure of overlap) and Spearman’s correlation coefficient. Subset analysis was performed evaluating results between small ( Results: The figure shows examples of CNN segmentation. The median [IQR] measured lesion volume and DSI were 25 [13-46] mL and 66% [35-75%], respectively. The correlation of MLV with ALV was 86% (P Discussion: Automatic DWI lesion segmentation for large lesions is feasible using CNN. CNN tended to overestimate the volumes of small lesions. Prior methods have used a priori heuristics or morphometric operations to remove artifacts. CNN methods show promise for “learning” to discriminate artifacts from real lesions.

This chapter reviews the diagnostic imaging findings of the brain during and after surgery, including intraoperative MRI, brain tumor surgery and treatment accessories, resection cavities, Ommaya reservoirs, chemotherapy wafers, brachytherapy, as well as neurodegenerative, neuropsychiatric, and epilepsy surgery

Background Neuroimaging may guide acute stroke treatment by measuring the volume of brain tissue in the irreversibly injured "ischemic core." The most widely accepted core volume measurement technique is diffusion-weighted MRI (DWI). However, some claim that measuring regional cerebral blood flow (CBF) with CT perfusion imaging (CTP), and labeling tissue below some threshold as the core, provides equivalent estimates. We tested whether any threshold allows reliable substitution of CBF for DWI. Methods 58 patients with suspected stroke underwent DWI and CTP within six hours of symptom onset. A neuroradiologist outlined DWI lesions. In CBF maps, core pixels were defined by thresholds ranging from 0%-100% of normal, in 1% increments. Replicating prior studies, we used receiver operating characteristic (ROC) curves to select thresholds that optimized sensitivity and specificity in predicting DWI-positive pixels, first using only pixels on the side of the brain where infarction was clinically suspected ("unilateral" method), then including both sides ("bilateral"). We quantified each method and threshold's accuracy in estimating DWI volumes, using sums of squared errors (SSE). For the 23 patients with follow-up studies, we assessed whether CBF-derived volumes inaccurately exceeded follow-up infarct volumes. Results The areas under the ROC curves were 0.89 (unilateral) and 0.90 (bilateral). Various metrics selected optimum CBF thresholds ranging from 29%-32%, with sensitivities of 0.79-0.81, and specificities of 0.83-0.85. However, for the unilateral and bilateral methods respectively, volume estimates derived from all CBF thresholds above 28% and 22% were less accurate than disregarding imaging and presuming every patient's core volume to be zero. The unilateral method with a 30% threshold, which recent clinical trials have employed, produced a mean core overestimation of 65 mL (range: -82-191), and exceeded follow-up volumes for 83% of patients, by up to 191 mL. Conclusion CTP-derived CBF maps cannot substitute for DWI in measuring the ischemic core.

Late enhancement (LE) multi-slice computed tomography (leMDCT) was introduced for the visualization of (intra-) myocardial fibrosis in Hypertrophic Cardiomyopathy (HCM). LE is associated with adverse cardiac events. This analysis focuses on leMDCT derived LV muscle mass (LV-MM) which may be related to LE resulting in LE proportion for potential risk stratification in HCM.N=26 HCM-patients underwent leMDCT (64-slice-CT) and cardiovascular magnetic resonance (CMR). In leMDCT iodine contrast (Iopromid, 350 mg/mL; 150mL) was injected 7 minutes before imaging. Reconstructed short cardiac axis views served for planimetry. The study group was divided into three groups of varying LV-contrast. LeMDCT was correlated with CMR.The mean age was 64.2 ± 14 years. The groups of varying contrast differed in weight and body mass index (p 0.05). In the group with good LV-contrast assessment of LV-MM resulted in 147.4 ± 64.8 g in leMDCT vs. 147.1 ± 65.9 in CMR (p 0.05). In the group with sufficient contrast LV-MM appeared with 172 ± 30.8 g in leMDCT vs. 165.9 ± 37.8 in CMR (p 0.05). Overall intra-/inter-observer variability of semiautomatic assessment of LV-MM showed an accuracy of 0.9 ± 8.6 g and 0.8 ± 9.2 g in leMDCT. All leMDCT-measures correlated well with CMR (r 0.9).LeMDCT primarily performed for LE-visualization in HCM allows for accurate LV-volumetry including LV-MM in 90% of the cases.• LeMDCT of relatively low contrast allows for LV planimetry in HCM. • The correlation of leMDCT-based LV volumetry with gold-standard CMR was excellent (r 0.9). • LeMDCT requires approximately 2.0mL/kgBW of dye to achieve acceptable contrast.

Background and Purpose— Major anterior circulation ischemic strokes caused by occlusion of the distal internal carotid artery or proximal middle cerebral artery or both account for about one third of ischemic strokes with mostly poor outcomes. These strokes are treatable by intravenous tissue-type plasminogen activator and endovascular methods. However, dynamics of infarct growth in these strokes are poorly documented. The purpose was to help understand infarct growth dynamics by measuring acute infarct size with diffusion-weighted imaging (DWI) at known times after stroke onset in patients with documented internal carotid artery/middle cerebral artery occlusions. Methods— Retrospectively, we included 47 consecutive patients with documented internal carotid artery/middle cerebral artery occlusions who underwent DWI within 30 hours of stroke onset. Prospectively, 139 patients were identified using the same inclusion criteria. DWI lesion volumes were measured and correlated to time since stroke onset. Perfusion data were reviewed in those who underwent perfusion imaging. Results— Acute infarct volumes ranged from 0.41 to 318.3 mL. Infarct size and time did not correlate ( R 2 =0.001). The majority of patients had DWI lesions that were 8 hours after stroke onset. DWI lesions corresponded to areas of greatly reduced perfusion. Conclusions— Poor correlation between infarct volume and time after stroke onset suggests that there are factors more powerful than time in determining infarct size within the first 30 hours. The observations suggest that highly variable cerebral perfusion via the collateral circulation may primarily determine infarct growth dynamics. If verified, clinical implications include the possibility of treating many patients outside traditional time windows.

Selecting acute ischemic stroke patients for reperfusion therapy on the basis of a diffusion-perfusion mismatch has not been uniformly proved to predict a beneficial treatment response. In a prior study, we have shown that combining clinical with MR imaging thresholds can predict clinical outcome with high positive predictive value. In this study, we sought to validate this predictive model in a larger patient cohort and evaluate the effects of reperfusion therapy and stroke side.One hundred twenty-three consecutive patients with anterior circulation acute ischemic stroke underwent MR imaging within 6 hours of stroke onset. DWI and PWI volumes were measured. Lesion volume and NIHSS score thresholds were used in models predicting good 3-month clinical outcome (mRS 0-2). Patients were stratified by treatment and stroke side.Receiver operating characteristic analysis demonstrated 95.6% and 100% specificity for DWI70 mL and NIHSS score20 to predict poor outcome, and 92.7% and 91.3% specificity for PWI (mean transit time)50 mL and NIHSS score8 to predict good outcome. Combining clinical and imaging thresholds led to an 88.8% (71/80) positive predictive value with a 65.0% (80/123) prognostic yield. One hundred percent specific thresholds for DWI (103 versus 31 mL) and NIHSS score (20 versus 17) to predict poor outcome were significantly higher in treated (intravenous and/or intra-arterial) versus untreated patients. Prognostic yield was lower in right- versus left-sided strokes for all thresholds (10.4%-20.7% versus 16.9%-40.0%). Patients with right-sided strokes had higher 100% specific DWI (103.1 versus 74.8 mL) thresholds for poor outcome, and the positive predictive value was lower.Our predictive model is validated in a much larger patient cohort. Outcome may be predicted in up to two-thirds of patients, and thresholds are affected by stroke side and reperfusion therapy.

A 29-year-old man was admitted to the hospital because of headache, vomiting, photophobia, diplopia, and stiff neck. He was born in Southeast Asia. Brain imaging showed diffuse leptomeningeal enhancement. Cultures were sterile. A diagnostic procedure was performed.

A 51-year-old man presented to an outside emergency department with progressive somnolence, memory impairment, and gait instability for 5 weeks, with acute worsening of symptoms 2 days prior to presentation. The patient was a former cigarette smoker, with a history of hypertension and coronary artery disease. He otherwise had no significant medical history. Magnetic resonance imaging (MRI) performed at the outside facility revealed bilateral expansile contrast-enhancing lesions within the thalami. The leading diagnostic considerations were neoplasm or infectious viral encephalitis. The patient was referred to our facility and admitted for further evaluation. On physical examination, the patient was hypertensive (blood pressure1⁄4 175/87), with otherwise normal vital signs. Neurologic examination revealed a flattened affect, a narrow shuffling gait, and cogwheel rigidity in the upper arms. Memory recall was impaired. Right lateral gaze nystagmus was present. The remainder of the examination was normal. Cerebrospinal fluid analysis revealed mild leukocytosis (6.7 white blood cell per high-power field), elevated levels of protein (97.3 mg/dL), and normal level of glucose (58 mg/ dL). The findings of cerebrospinal fluid gram stain, culture, venereal disease research laboratory test, herpes simplex virus polymerase chain reaction, and bacterial antigens were negative. The findings of blood carboxyhemoglobin, serum thiamine, serum Lyme, and antinuclear antibody titers were

Despite several landmark studies, the natural history of unruptured intracranial aneurysms (UIA) remains uncertain. Our aim was to identify or confirm factors predictive of rupture of UIA being observed conservatively with serial CT angiography (CTA) in a North American patient population.We performed a retrospective review of patients with UIA being followed with serial CTA studies from 1999 to 2010. The following features for each aneurysm were cataloged from the official radiologic reports and CTA images: maximum diameter, growth between follow-up studies, location, multiplicity, wall calcification, intraluminal thrombus and morphology. Univariate logistic regression analysis of the potential independent risk factors for aneurysm rupture was performed. Statistically significant risk factors from the univariate analysis were then entered into a multivariate logistic regression analysis.152 patients with a total of 180 UIA had at least two CTA studies. Six aneurysms in six different patients ruptured during the CTA follow-up period for an overall rupture rate of 3.3% and an annual rupture rate of 0.97%. All ruptured aneurysms were ≥9 mm. In the univariate analysis, the statistically significant predictors of aneurysm rupture were aneurysm size (p=0.003), aneurysm growth (p0.0001) and aneurysm multilobulation (p=0.001). The risk factors that remained significant following the multivariate analysis were growth (OR 55.9; 95% CI 4.47 to 700.08; p=0.002) and multilobulation (OR 17.4; 95% CI 1.52 to 198.4; p=0.022).Aneurysm morphology and interval growth are characteristics predictive of a higher risk of subsequent rupture during conservative CTA follow-up.

In the article entitled "Imaging Recommendations for Acute Stroke and Transient Ischemic Attack Patients: A Joint Statement by the American Society of Neuroradiology, the American College of Radiology and the Society of NeuroInterventional Surgery", we are proposing a simple, pragmatic approach that will allow the reader to develop an optimal imaging algorithm for stroke patients at their institution.

Implementation of intraoperative magnetic resonance imaging (iMRI) has been shown to optimize the extent of resection and safety of brain tumor surgery. In addition, iMRI can help account for the phenomenon of brain shift and can help to detect complications earlier than routine postoperative imaging, which can potentially improve patient outcome. The higher signal-to-noise ratio offered by 3 Tesla (T) iMRI compared with lower field strength systems is particularly advantageous. The purpose of this article is to review the imaging protocols, imaging findings, and technical considerations related to 3T iMRI. To maximize efficiency, iMRI sequences can be tailored to particular types of tumors and procedures, including nonenhancing brain tumor surgery, enhancing brain tumor surgery, transsphenoidal pituitary tumor surgery, and laser ablation. Unique imaging findings on iMRI include the presence of surgically induced enhancement, which can be a potential confounder for residual enhancing tumor, and hyperacute hemorrhage, which tends to have intermediate signal on T1-weighted sequences and high signal on T2-weighted sequences due to the presence of oxyhemoglobin. MR compatibility and radiofrequency shielding pose particularly stringent technical constraints at 3T and influence the design and usage of the surgical suite with iMRI.

IPAB : Independent Payment Advisory Board ACA : Patient Protection and Affordable Care Act PCORI : Patient Centered Outcomes Research Institute MedPAC : Medicare Payment Advisory Commission The Independent Payment Advisory Board (IPAB) is considered the most potent cost-cutting measure of

The Massachusetts General Hospital Neuroradiology Division employed an experience and evidence based approach to develop a neuroimaging algorithm to best select patients with severe ischemic strokes caused by anterior circulation occlusions (ACOs) for intravenous tissue plasminogen activator and endovascular treatment. Methods found to be of value included the National Institutes of Health Stroke Scale (NIHSS), non-contrast CT, CT angiography (CTA) and diffusion MRI. Perfusion imaging by CT and MRI were found to be unnecessary for safe and effective triage of patients with severe ACOs. An algorithm was adopted that includes: non-contrast CT to identify hemorrhage and large hypodensity followed by CTA to identify the ACO; diffusion MRI to estimate the core infarct; and NIHSS in conjunction with diffusion data to estimate the clinical penumbra.

Biliary tract carcinoma (BTC) is a fatal malignancy which aggressiveness contrasts sharply with its relatively mild and late clinical presentation. Novel molecular markers for early diagnosis and precise treatment are urgently needed. The purpose of this study was to evaluate the diagnostic and prognostic value of promoter hypermethylation of the SHOX2 and SEPT9 gene loci in BTC. Relative DNA methylation of SHOX2 and SEPT9 was quantified in tumor specimens and matched normal adjacent tissue (NAT) from 71 BTC patients, as well as in plasma samples from an independent prospective cohort of 20 cholangiocarcinoma patients and 100 control patients. Receiver operating characteristic (ROC) curve analyses were performed to probe the diagnostic ability of both methylation markers. DNA methylation was correlated to clinicopathological data and to overall survival. SHOX2 methylation was significantly higher in tumor tissue than in NAT irrespective of tumor localization (p

In this chapter we review the optimal imaging modalities for subacute and chronic stroke. We discuss the utility of computed tomography (CT) and multimodal CT imaging. Further, we analyze the importance of specific magnetic resonance imaging sequences, such as diffusion-weighted imaging for acute ischemic stroke, T2/fluid-attenuated inversion recovery for subacute and chronic stroke, and susceptibility imaging for detection of intracranial hemorrhages. Different ischemic stroke mechanisms are reviewed, and how these imaging modalities may aid in the determination of such. Further, we analyze how topographic patterns in ischemic stroke may provide important clues to the diagnosis, in addition to the temporal evolution of the stroke. Lastly, specific cerebrovascular occlusive diseases are reviewed, with emphasis on the optimal imaging modalities and their findings in each condition.

Overall improvement in the interpretation of images obtained in the emergency department and involvement in decision making will reinforce the participation of radiology in the local stroke team and will increase the added value of radiology to stroke care.

Background: Increases in FLAIR MRI signal intensity (SI) after acute ischemic stroke (AIS) have been proposed as “tissue clocks”, reflecting the degree of ischemic injury and potential for recovery in brain tissue. We hypothesize that lower SI increases will be a biomarker for less severe tissue injury and hence is potentially salvageable. To test this, we investigated patients who were treated with tPA to determine whether better outcomes were associated with lower FLAIR SI. Methods: Using our Get with the Guidelines database, we retrospectively analyzed AIS patients admitted between 2011 to 2013 who received full-dose tPA based on institutional protocols. Patients were included if they received a CT scan at our hospital before tPA therapy, and MRI performed < 1 h post CT included a usable FLAIR scan and evidence of stroke on acute DWI. SI ratio (SIR) was calculated on the FLAIR by selecting region of interests in hyperintense FLAIR areas that coincided with the acute DWI lesion and matching contralateral regions. Logistic regression analysis was performed using forward stepwise analysis to combine age, sex, admission NIHSS, SIR and onset-to-treatment (OTT) time to predict discharge outcome. Good outcome was defined as discharge to home or in-patient rehabilitation hospital. Results: There were 129 AIS patients who received tPA, and 57 met our imaging criteria. Patient characteristics were: mean±SD age 70±15 years, median [IQR] NIHSS 13 [7-18], OTT 2.1±1.1 h, time-to-MRI 2.1±1.0 h, 58% female and median SIR 1.13 [1.05-1.26]. On a univariate basis, only age (P Discussion: Controlling for age and admission NIHSS, we found that lower FLAIR SIR was a significant predictor of discharge outcome while OTT was not. This suggests that “tissue clocks” may be more accurate than “time clocks” for predicting tissue outcome, and ultimately functional outcome.

In this chapter we review the optimal imaging modalities for subacute and chronic stroke. We discuss the utility of computed tomography (CT) and multimodal CT imaging. Further, we analyze the importance of specific magnetic resonance imaging sequences, such as diffusion-weighted imaging for acute ischemic stroke, T2/fluid-attenuated inversion recovery for subacute and chronic stroke, and susceptibility imaging for detection of intracranial hemorrhages. Different ischemic stroke mechanisms are reviewed, and how these imaging modalities may aid in the determination of such. Further, we analyze how topographic patterns in ischemic stroke may provide important clues to the diagnosis, in addition to the temporal evolution of the stroke. Lastly, specific cerebrovascular occlusive diseases are reviewed, with emphasis on the optimal imaging modalities and their findings in each condition.