Editor’s Choices

Quantifying Intracranial Plaque Permeability with Dynamic Contrast-Enhanced MRI: A Pilot Study

Editor’s Choice

The purpose of this study was to use DCE MR imaging to quantify the contrast permeability of intracranial atherosclerotic disease plaques in 10 symptomatic patients and to compare these parameters against existing markers of plaque volatility using black-blood MR imaging pulse sequences. Ktrans and fractional plasma volume (Vp) measurements were higher in plaques versus healthy white matter and similar or less than values in the choroid plexus. Only Ktrans correlated significantly with time from symptom onset. Dynamic contrast-enhanced MR imaging parameters were not found to correlate significantly with intraplaque enhancement or hyperintensity. The authors suggest that Ktrans may be an independent imaging biomarker of acute and symptom-associated pathologic changes in intracranial atherosclerotic disease plaques.

Limited Dorsal Myeloschisis and Congenital Dermal Sinus: Comparison of Clinical and MR Imaging Features

Editor’s Choice

These investigators retrospectively reviewed the clinical and MR imaging findings of 12 patients with limited dorsal myeloschisis and 10 patients with congenital dermal sinus. A crater covered with pale epithelium was the most common skin lesion in limited dorsal myeloschisis (83%). Infectious complications were common in congenital dermal sinus (60%), but not found in limited dorsal myeloschisis. They show that limited dorsal myeloschisis has distinct MR imaging features including a visible intrathecal tract with dorsal tenting of the cord at the tract-cord union.

Emergent Endovascular Management of Long-Segment and Flow-Limiting Carotid Artery Dissections in Acute Ischemic Stroke Intervention with Multiple Tandem Stents

Editor’s Choice

The authors investigated the role of emergent endovascular stenting of long-segment carotid dissections in the acute ischemic stroke setting in 15 patients. They specifically evaluated long-segment carotid dissections requiring stent reconstruction with multiple tandem stents (≥ 3 stents) and presenting with acute (<12 hours) ischemic stroke symptoms (NIHSS score, ≥ 4). Carotid stent reconstruction was successful in all patients with no residual stenosis or flow limitation. Nine patients (60%) harbored intracranial occlusions, and 6 patients (40%) required intra-arterial thrombolysis/thrombectomy, achieving 100% TICI 2b–3 reperfusion. They conclude that emergent stent reconstruction of long-segment and flow-limiting carotid dissections in acute ischemic stroke intervention is safe and effective, with favorable clinical outcomes.

Metabolic Abnormalities in the Hippocampus of Patients with Schizophrenia: A 3D Multivoxel MR Spectroscopic Imaging Study at 3T

Editor’s Choice

Nineteen patients with schizophrenia and 11 matched healthy controls underwent MR imaging and multivoxel point-resolved 1H-MRS at 3T to obtain their hippocampal gray matter absolute NAA, Cr, and Cho concentrations. Patients’ average hippocampal GM Cr concentrations were 19% higher than those of controls. NAA and Cho showed no differences. The authors conclude that the findings suggest the hippocampal volume deficit in schizophrenia is not due to net loss of neurons, which is in agreement with histopathology studies but not with prior 1H-MR spectroscopy reports. Elevated Cr would be consistent with hippocampal hypermetabolism.

Comparison of Quantitative Cerebral Blood Flow Measurements Performed by Bookend Dynamic Susceptibility Contrast and Arterial Spin-Labeling MRI in Relapsing-Remitting Multiple Sclerosis

Editor’s Choice

Both dynamic susceptibility contrast perfusion with bookend T1-calibration and pseudocontinuous arterial spin-labeling have been used recently for CBF quantification in relapsing-remitting MS. The authors compared pseudocontinuous arterial spin-labeling CBF with the bookend technique in a prospective cohort of 19 healthy controls, 19 subjects with relapsing-remitting MS without cognitive impairment, and 20 subjects with relapsing-remitting MS with cognitive impairment. Voxelwise paired t tests revealed no significant CBF differences between techniques after normalization of global meanintensities. They conclude that there is agreement between pseudocontinuous arterial spin-labeling and bookend technique CBF measurements in healthy controls and patients with relapsing-remitting MS.

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.