Table of Contents
- Genetically Defined Oligodendroglioma Is Characterized by Indistinct Tumor Borders at MRI
The authors wanted to determine whether imaging characteristics previously associated with oligodendroglial tumors were still applicable given the 2016 WHO classification that made IDH mutation and 1p/19q codeletion the defining features of oligodendroglioma. They found that 92% of genetically defined oligodendrogliomas had noncircumscribed borders, compared with 45% of non-1p/19q codeleted tumors with at least partial histologic oligodendroglial morphology. Ninety-nine percent of oligodendrogliomas were heterogeneous on T1- and/or T2-weighted imaging.
- Combining Diffusion Tensor Metrics and DSC Perfusion Imaging: Can It Improve the Diagnostic Accuracy in Differentiating Tumefactive Demyelination from High-Grade Glioma?
Fourteen patients with tumefactive demyelinating lesions and 21 patients with high-grade gliomas underwent MR imaging with conventional, DTI, and DSC perfusion imaging. Conventional imaging sequences had a sensitivity of 80.9% and specificity of 57.1% in differentiating high-grade gliomas from tumefactive demyelinating lesions. DTI metrics (p:q tensor decomposition) and DSC perfusion demonstrated a statistically significant difference among enhancing portions in tumefactive demyelinating lesions and high-grade gliomas. The highest specificity was found for ADC, the anisotropic component of the diffusion tensor, and relative CBV. The authors conclude that DTI and DSC perfusion add profoundly to conventional imaging in differentiating tumefactive demyelinating lesions and high-grade gliomas.
- MR Imaging of Individual Perfusion Reorganization Using Superselective Pseudocontinuous Arterial Spin-Labeling in Patients with Complex Extracranial Steno-Occlusive Disease
Super selective pseudocontinuous arterial spin-labeling with a circular labeling spot enabling selective vessel labeling was added to routine imaging in a prospective pilot study in 50 patients with extracranial steno-occlusive disease. The detected vessel occlusions/stenoses and perfusion patterns corresponded between cerebral DSA and super selective pseudocontinuous ASL maps in all cases. Perfusion deficits on DSC-CBF maps significantly correlated with those on super selective pseudocontinuous ASL maps. The authors conclude that superselectivepseudocontinuousASL is a robust technique for regional brain perfusion imaging, suitable for the noninvasive diagnostics of individual patient perfusion patterns.
- Feasibility of Flat Panel Detector CT in Perfusion Assessment of Brain Arteriovenous Malformations: Initial Clinical Experience
Five patients with brain arteriovenous malformations were studied with flat panel detector CT, DSC-MR imaging, and vessel-encoded pseudocontinuous arterial spin-labeling. Flat panel detector CT, which was originally thought to measure blood volume, correlated more closely with ASL-CBF and DSC-CBF than with DSC-CBV. Flat panel detector CT perfusion depends on the time point chosen for data collection, which is triggered early in patients with AVMs. This finding, in combination with high data variability, makes flat panel detector CT inappropriate for perfusion assessment in brain AVMs.
- Evaluation of Collaterals and Clot Burden Using Time-Resolved C-Arm Conebeam CT Angiography in the Angiography Suite: A Feasibility Study
Ten C-arm conebeam CT perfusion datasets from 10 subjects with acute ischemic stroke acquired before endovascular treatment were retrospectively processed to generate time-resolved conebeam CTA. From time-resolved conebeam CTA, 2 experienced readers evaluated the clot burden and collateral flow in consensus by using previously reported scoring systems and assessed the clinical value of this novel imaging technique. The 2 readers agreed that time-revolved C-arm conebeam CTA was the preferred method for evaluating the clot burden and collateral flow compared with other conventional imaging methods. They conclude that comprehensive evaluations of clot burden and collateral flow are feasible by using time-resolved C-arm conebeam CTA data acquired in the angiography suite.
- Imaging Characteristics of Pediatric Diffuse Midline Gliomas with Histone H3 K27M Mutation
The 2016 WHO Classification of Tumors of the Central Nervous System includes “diffuse midline glioma with histone H3 K27M mutation” as a new diagnostic entity. This study of 33 patients with diffuse midline gliomas found histone H3 K27M mutation was present in 24 patients (72.7%) and absent in 9 (27.3%). The location was the thalamus in 27.3%; the pons in 42.4%; within the vermis/fourth ventricle in 15%; and the spinal cord in 6%. The radiographic features of diffuse midline gliomas with histone H3 K27M mutation were highly variable, ranging from expansile masses without enhancement or necrosis with large areas of surrounding infiltrative growth to peripherally enhancing masses with central necrosis with significant mass effect.