BACKGROUND AND PURPOSE:Prior studies regarding acute toxic leukoencephalopathy (ATL) are either small, or preliminary. Our aim was to evaluate etiologies of and differences in imaging severity and outcomes among various etiologies of ATL. MATERIALS AND METHODS:MRIs of patients with suspected ATL over 15 years were retrospectively reviewed; inclusion criteria were: MRI Ͻ3 weeks of presentation with both DWI and FLAIR. These were jointly graded by two neuroradiologists via a previously described score of severity. Clinical outcome was evaluated via both modified Rankin (mRS) and ATL outcome (ATLOS) scores, each being correlated with the DWI and FLAIR scores. Etiologic subgroups of n Ͼ 6 patients were statistically compared. RESULTS:Of 101 included patients, the 4 subgroups of n Ͼ 6 were the following: chemotherapy (n ϭ 35), opiates (n ϭ 19), acute hepatic encephalopathy (n ϭ 14), and immunosuppressants (n ϭ 11). Other causes (n ϭ 22 total) notably included carbon monoxide (n ϭ 3) metronidazole (n ϭ 2), and uremia (n ϭ 1). The mean DWI/FLAIR severity scores were 2.6/2.3, 3.3/3.3, 2.1/2.1 and 2.0/2.5 for chemotherapeutics, opiates, AHE and immunosuppressants, respectively, with significant differences in both imaging severity and outcome (P ϭ .003-.032) among subgroups, particularly immunosuppressant versus chemotherapy-related ATL and immunosuppressants versus opiates (P ϭ .004 -.032) related ATL. DWI and FLAIR severity weakly correlated with outcome ( ϭ 0.289 -.349, P Ͻ .005) but correlated stronger in the chemotherapy ( ϭ 0.460 -.586, P Ͻ .010) and opiate ( ϭ.472-.608, P Ͻ .05) subgroups, which had the worst outcomes. ATL clinically resolved in 36%, with severe outcomes in 23% (coma or death, 9/16 deaths from fludarabine). Notable laboratory results were elevated CSF myelin basic protein levels in 8/9 patients and serum blood urea nitrogen levels in 24/91. CONCLUSIONS:Clinical outcomes of ATL vary on the basis of etiology, being worse in chemotherapeutic-and opiate-related ATL. Uremia may be a predisposing or exacerbating factor. ABBREVIATIONS:AHE ϭ acute hepatic/hyperammonemic encephalopathy; ATL ϭ acute toxic leukoencephalopathy; ATLOS ϭ acute toxic leukoencephalopathy outcome score; CTL ϭ chronic toxic leukoencephalopathy; MBP ϭ myelin basic protein; NAWMϭ normal appearing white matter; PRES ϭ posterior reversible encephalopathy syndrome; PVWM ϭ periventricular white matter Indicates open access to non-subscribers at www.ajnr.org Indicates article with on-line appendix. http://dx.

BackgroundClot perviousness in large vessel occlusion has been shown to be associated with improved recanalization outcomes with mechanical thrombectomy and intravenous thrombolysis.ObjectiveTo evaluate the association between clot perviousness based on thrombus attenuation increase (TAI) on CT, and histologic composition of clots in acute ischemic stroke (AIS).MethodsA retrospective review was completed of patients with AIS secondary to large vessel occlusion, non-contrast CT (NCCT) and CT angiography (CTA) images, and histologic analysis of the retrieved clot. TAI was measured by subtracting clot attenuation on NCCT from the attenuation on CTA. Up to 3 regions of interest (ROIs) were evaluated on each clot; the average attenuation was used for analysis if multiple ROIs were assessed. Pervious clots were defined as TAI ≥10 Hounsfield units (HUs); impervious clots had TAI <10 HU. Histopathologic analyses of clots were assessed for relative compositions of red blood cells (RBCs), white blood cells (WBCs), fibrin, and platelets/other.Results57 patients were included. Pervious clots were more likely to be RBC rich (p=0.04); impervious clots were more likely to be fibrin and WBC rich (p=0.01 for both). Pervious clots also had greater RBC density than impervious clots (49.8% and 33.0%, respectively; p=0.006); fibrin density of pervious clots was lower than that of impervious clots (17.8% and 23.2%, respectively; p=0.02).ConclusionClot perviousness, assessed on NCCT and CTA imaging, is associated with higher RBC density and lower fibrin density, offering a possible explanation for the higher rates of successful thrombectomy and favorable clinical outcome seen in such patients.

BackgroundLeukoaraiosis and collateral blood flow are processes that involve small vessels, the former related to flow within the deep perforating arterioles and the latter involving the small, cortical pial-pial connections, both of which are independently used to predict cerebrovascular events and treatment outcomes. The aim of this study was to investigate their relationship to each other.MethodsWe retrospectively reviewed patients who underwent mechanical thrombectomy for stroke with pre-procedural CT imaging within 24 hours of the onset of symptoms. Leukoaraiosis was graded by the total Fazekas score on non-contrast CT, periventricular white matter (PVWM) and deep white matter (DWM) scores, both ranging from 0 to 3. Collateral cerebral blood flow was measured by the American Society of Interventional and Therapeutic Radiology/Society of Interventional Radiology (ASITN/SIR) collateral scale.Results178 patients were included with a mean age of 67.6±14.8 years. We found an inverse relationship between total Fazekas score and collateral flow (p<0.0001). Among patients with good collaterals, 75.1% had total Fazekas scores of 0–2, compared with 36.6% of patients with moderate collaterals and 32.7% of patients with poor collaterals with total Fazekas scores of 0–2. Mean Fazekas scores were 1.6±1.5, 3.1±1.5 and 3.4±1.6 for good, moderate and poor collaterals, respectively (p<0.0001). On multivariate analysis, total Fazekas score was the only variable independently associated with collateral status (p<0.0001).ConclusionsIncreasing severity of leukoaraiosis is associated with poor collateral grade among ischemic stroke patients with anterior circulation large vessel occlusion. These findings suggest that leukoaraiosis may be a marker for global cerebrovascular dysfunction.

Digital subtraction myelography is a valuable diagnostic technique to detect the exact location of CSF leaks in the spine to facilitate appropriate diagnosis and treatment of spontaneous spinal CSF leaks. Digital subtraction myelography is an excellent diagnostic tool for assessment of various types of CSF leaks, and lateral decubitus digital subtraction myelography is increasingly being used to diagnose CSF-venous fistulas. Lateral decubitus digital subtraction myelography differs from typical CT and fluoroscopy-guided myelograms in many ways, including equipment, supplies, and injection and image-acquisition techniques. Operators should be familiar with techniques, common pitfalls, and artifacts to improve diagnostic yield and prevent nondiagnostic examinations.

Acute ischemic infarcts of the insulae, lentiform nuclei, and middle corona radiata tend to have larger volumes, more severe presentations, and worse outcomes, whereas brain stem and thalamic infarcts have greater symptom severity relative to smaller lesion volumes.

Background and purposeThe Alberta Stroke Program Early CT Score (ASPECTS) is a commonly used scoring system to select patients with stroke for endovascular treatment (EVT). However, the inter- and intra-reader variability is high.ObjectiveTo determine whether the inter- and intra-reader variability is different for various regions of the ASPECTS scoring system by evaluating the interobserver variability of ASPECTS between different readers in a per-region analysis.Materials and methodsAll patients with acute ischemic stroke who proceeded to EVT in our institutions over a 4-year period were retrospectively identified from a prospectively maintained database. Images were reviewed by two experienced neuroradiologists, who recalculated the ASPECTS independently. We examined each region of the ASPECTS system to evaluate agreement between the raters in each area.Results375 patients were included. The median total ASPECTS was 9 (IQR 8–9). The most common region showing ischemic change was the insula, with the M6 region being least commonly affected. Overall interobserver agreement for ASPECTS using Cohen’s κ was 0.56 (95% CI 0.51 to 0.61). The region with the highest agreement was the insula (κ=0.56; 0.48 to 0.64). The region with the lowest agreement was M3 (κ=0.34; 0.12 to 0.56). Agreement was relatively good when ASPECTS were dichotomized into 0–5 versus 6–10 (κ=0.66; 0.49 to 0.84).ConclusionsSubstantial interobserver variability is found when calculating ASPECTS. This variability is region dependent, and practitioners should take this into account when using ASPECTS for treatment decisions in patients with acute stroke.

BACKGROUND AND PURPOSE: Ischemic stroke is the leading cause of long-term disability in adults, but our ability to prognosticate from baseline imaging data is limited. The ASPECTS measures ischemic change in the middle cerebral artery territory on noncontrast CT based on 10 anatomic regions. Here, we investigated whether infarction in particular regions was associated with worse long-term outcome. MATERIALS AND METHODS:We identified consecutive patients receiving mechanical thrombectomy for ICA/MCA occlusion at 2 comprehensive stroke centers. Pretreatment ASPECTS was assessed by 2 blinded reviewers. Clinical data including demographics, baseline NIHSS score, and 90-day mRS were collected. The relationship between individual ASPECTS regions and the mRS score (0-2 versus 3-6) was assessed using multivariable logistic regression.RESULTS: Three hundred fifty-three patients were included (mean age, 70 years; 46% men), of whom 214 had poor outcome (mRS ¼ 3-6). Caudate (OR ¼ 3.26; 95% CI, 1.33-8.82), M4 region (OR ¼ 2.94; 95% CI, 1.09-9.46), and insula (OR ¼ 1.75; 95% CI, 1.08-2.85) infarcts were associated with significantly greater odds of poor outcome, whereas M1 region infarction reduced the odds of poor outcome (OR ¼ 0.38; 95% CI, 0.14-0.99). This finding remained unchanged when restricted to only patients with good recanalization. No significant associations were found by laterality. Similarly, no region was predictive of neurologic improvement during the first 24 hours or of symptomatic intracerebral hemorrhage. CONCLUSIONS:Our results indicate that ASPECTS regions are not equal in their contribution to functional outcome. This finding suggests that patient selection based on total ASPECTS alone might be insufficient, and infarct topography should be considered when deciding eligibility for thrombectomy.

A 47-year-old female presented to clinic with a 5-year history of a left buttock mass. The patient's hemoglobin was low (9.7 g/dL); laboratory analysis was otherwise unremarkable. Ultrasound of the left gluteal region demonstrated a heterogeneous vascular solid lesion. Magnetic resonance and computed tomography imaging showed an enhancing mass extending from the left ischioanal fossa through the levator ani muscle into the pelvis. Biopsy revealed bland-appearing spindle-shaped cells positive for estrogen and progesterone receptors, consistent with an aggressive angiomyxoma. The mass was surgically excised without complication. To date, follow-up imaging has not demonstrated evidence of tumor recurrence.