Editor’s Choices

Progressing Bevacizumab-Induced Diffusion Restriction Is Associated with Coagulative Necrosis Surrounded by Viable Tumor and Decreased Overall Survival in Patients with Recurrent Glioblastoma

Editor’s Choice

The authors explored regions of diffusion restriction following bevacizumab therapy in patients with glioblastoma by 1) analyzing tissue samples from patients at postmortem to pathologically confirm tumor cellularity or coagulative necrosis and 2) assessing the patient populationto determine the effect that these lesions have on overall survival. The postmortem examinations were performed on 6 patients with recurrent glioblastoma on bevacizumab with progressively growing regions of diffusion restriction. ADC values were extracted from regions of both hypercellular tumor and necrosis. They conclude that progressive diffusion-restricted lesions were pathologically confirmed to be coagulative necrosis surrounded by viable tumor and associated with decreased overall survival.

Mechanical Thrombectomy in Patients with Acute Ischemic Stroke and Lower NIHSS Scores: Recanalization Rates, Periprocedural Complications, and Clinical Outcome

Editor’s Choice

This is a retrospective analysis of 484 patients in a prospectively collected stroke data base. The inclusion criteria were anterior circulation ischemic stroke treated with mechanical thrombectomy at a single institution between September 2010 and October 2015 with an NIHSS score of ≤8. The purpose was to assess the clinical and interventional data in patients treated with mechanical thrombectomy in case of ischemic stroke with mild-to-moderate symptoms (n = 33). Recanalization (TICI 2b–3) was achieved in 26 (78.7%) patients. Two cases of symptomatic intracranial hemorrhage occurred. Favorable (mRS 0–2) and moderate (mRS 0–3) clinical 90-day outcome was achieved in 63.6% and 90.9% of patients, respectively. The authors conclude that the clinical outcome of patients undergoing mechanical thrombectomy for acute ischemic mild stroke due to large-vessel occlusion is predominately favorable, even in a prolonged time window.

Comparison of CTA- and DSA-Based Collateral Flow Assessment in Patients with Anterior Circulation Stroke

Editor’s Choice

The authors set out to determine the agreement between collateral flow assessment on CTA and DSA and their respective associations with clinical outcome. They used patient data that was randomized in MR CLEAN with middle cerebral artery occlusion and both baseline CTA images and complete DSA runs. Collateral flow on CTA and DSA was graded 0 (absent) to 3 (good).Of 45 patients with evaluable imaging data, collateral flow was graded on CTA as 0, 1, 2, 3 for 3, 10, 20, and 12 patients, respectively, and on DSA for 12, 17, 10, and 6 patients, respectively. The adjusted odds ratio for favorable outcome on mRS was 2.27 and 1.29 for CTA and DSA, respectively. The relationship between the dichotomized collateral score and mRS 0–2 was significant for CTA, but not for DSA. They conclude that the commonly applied collateral flow assessment on CTA and DSA showed large differences and that these techniques are not interchangeable. CTA was significantly associated with mRS at 90 days, whereas DSA was not.

Early Biomarkers from Conventional and Delayed-Contrast MRI to Predict the Response to Bevacizumab in Recurrent High-Grade Gliomas

Editor’s Choice

Twenty-four patients with recurrent high-grade gliomas were scanned before and during bevacizumab treatment with standard and delayed-contrast MRI. The mean change in lesion volumes of responders (overall survival, 1 year) and nonresponders (overall survival, <1 year) was evaluated. Treatment-response-assessment maps (TRAMs) were calculated by subtracting conventional T1WI (acquired a few minutes postcontrast) from delayed T1WI (acquired with a delay of 1 hour postcontrast). These maps depict the spatial distribution of contrast accumulation and clearance. At progression, the increase in lesion volumes in delayed-contrast MR imaging was 37.5% higher than the increase in conventional T1WI. The authors conclude that the benefit of standard and delayed-contrast MRI for assessing and predicting the response to bevacizumab was demonstrated and that the increased sensitivity of delayed-contrast MRI reflects its potential contribution to the management of bevacizumab-treated patients with recurrent HGG.

Imaging Appearance of SMARCB1 (INI1)-Deficient Sinonasal Carcinoma: A Newly Described Sinonasal Malignancy

Editor’s Choice

SMARCB1 (INI1) is a tumor-suppressor gene that has been implicated in a growing number of malignancies involving multiple anatomic sites, including the kidneys, soft tissues, and the CNS (See OMIM *601607). The authors describe a case series of 17 patients collected from 6 different centers to give a comprehensive description of the appearance of these tumors on CT, MR, and PET/CT studies. SMARCB1 (INI1)-deficient sinonasal carcinoma should be included in the differential diagnosis of a central sinonasal mass demonstrating aggressive imaging features, particularly when there is associated calcification.

Ocular Signs Caused by Dural Arteriovenous Fistula without Involvement of the Cavernous Sinus: A Case Series with Review of the Literature

Editor’s Choice

Ocular signs are unusual in the presentation of cranial dural arteriovenous fistulas in locations other than the cavernous sinus. Between 2000–2015, 13 patients met the inclusion criteria for this retrospective analysis. The most common signs were chemosis (61.5%), loss of visual acuity (38.5%), exophthalmia (38.5%), and ocular hypertension (7.7%). Dural arteriovenous fistulas presenting with ocular signs were classified into 4 types due to their pathologic mechanism (local venous reflux into the superior ophthalmic vein, massive venous engorgement of the cerebrum responsible for intracranial hypertension, compression of an oculomotor nerve by a venous dilation, or intraorbital fistula with drainage into the superior ophthalmic vein).

Magnetic Susceptibility from Quantitative Susceptibility Mapping Can Differentiate New Enhancing from Nonenhancing Multiple Sclerosis Lesions without Gadolinium Injection

Editor’s Choice

In 54 patients, new T2-weighted lesions were evaluated for enhancement on conventional T1-weighted imaging with gadolinium, and their susceptibility values were measured on quantitative susceptibility mapping. Eighty-six of 133 new lesions that were gadolinium-enhancing had relative susceptibility values significantly lower than those of nonenhancing lesions. Using susceptibility values to discriminate enhancing from nonenhancing lesions showed a sensitivity of 88.4% and specificity of 91.5%, with a cutoff value of 11.2 parts per billion for QSM.

Risk Factors for Ischemic Complications following Pipeline Embolization Device Treatment of Intracranial Aneurysms: Results from the IntrePED Study

Editor’s Choice

This is a retrospective subanalysis of the IntrePED study, which has beenpreviously published (AJNR Am J Neuroradiol 2015;36:108–15).Seven hundred ninety-three patients with 906 treated aneurysms were enrolled. Thirty-six (4.5%) patients had postoperative acute ischemic stroke, 21 of which occurred within 1 week of the procedure. There was no difference in the rate of acute stroke between the anterior and posterior circulations. Stroke rate was 3% in patients with 1 PED, and 7% in those with 2 PEDs. With multivariate analysis, the only variable independently associated with postoperative stroke was treatment of fusiform aneurysms. Among the patients with stroke, 10 (27.0%) died and 26 (73.0%) had major neurologic morbidity. The authors conclude that acute ischemic stroke following treatment of intracranial aneurysms with the PED is an uncommon but devastating complication, with 100% of patients having major morbidity or mortality.

Quantitative Susceptibility Mapping and R2* Measured Changes during White Matter Lesion Development in Multiple Sclerosis: Myelin Breakdown, Myelin Debris Degradation and Removal, and Iron Accumulation

Editor’s Choice

The authors characterized lesion changes on quantitative susceptibility mapping and R2* at various gadolinium enhancement stages (nodular, shell-like, nonenhancing) in 64 patients with 203 lesions. They found that: 1) active MS lesions with nodular enhancement show R2* decrease but no quantitative susceptibility mapping change; 2) late active lesions with peripheral enhancement show R2* decrease and quantitative susceptibility mapping increase in the lesion center; and 3) nonenhancing lesions show both quantitative susceptibility mapping and R2* increase, reflecting iron accumulation.

Association of Automatically Quantified Total Blood Volume after Aneurysmal Subarachnoid Hemorrhage with Delayed Cerebral Ischemia

Editor’s Choice

The authors retrospectively studied clinical and radiologic data of 333 consecutive patients with aneurysmal SAH between January 2009 and December 2011. Adjusted odds ratios werecalculated for the association between automatically quantified total blood volume on NCCT and delayed cerebral ischemia (clinical, radiologic, and both). The adjusted OR of total blood volume for delayed cerebral ischemia was 1.02 per milliliter of blood. They conclude that a higher total blood volume measured with the automated quantification method is significantly associated with delayed cerebral ischemia.