Table of Contents
Perspectives
Review Article
General Contents
- Deep-Learning Convolutional Neural Networks Accurately Classify Genetic Mutations in Gliomas
MR imaging data and molecular information were retrospectively obtained from The Cancer Imaging Archives for 259 patients with either low- or high-grade gliomas. A convolutional neural network was trained to classify IDH1 mutation status, 1p/19q codeletion, and MGMT promotor methylation status. Classification had high accuracy: IDH1 mutation status, 94%; 1p/19q codeletion, 92%; and MGMT promotor methylation status, 83%. The authors conclude that this shows the feasibility of a deep-learning CNN approach for the accurate classification of individual genetic mutations of both low- and high-grade gliomas and that the relevant MR imaging features acquired from an added dimensionality-reduction technique are concordant with existing literature, showing that neural networks are capable of learning key imaging components without prior feature selection or human directed training.
- Identification of Chronic Active Multiple Sclerosis Lesions on 3T MRI
MR imaging–pathologic studies have reported that paramagnetic rims on 7T susceptibility-based MR imaging identify, in vivo, a subset of MS lesions with compartmentalized inflammation at the lesion edge and associated remyelination failure. High-resolution T2* and phase MR imaging were collected in 20 patients with MS at 3T and 7T. Phase rims were seen in 34 lesions at 7T and in 36 lesions at 3T by consensus. Inter- and intra-rater reliability were “substantial/good” both at 3T and 7T analysis. Nearly all 7T paramagnetic rims can also be seen at 3T. Imaging at 3T opens the possibility of implementing paramagnetic rims as an outcome measure.
- Visualization and Classification of Deeply Seated Collateral Networks in Moyamoya Angiopathy with 7T MRI
This study aimed to evaluate morphologic patterns and the delineation of deeply seated collateral networks using ultra-high-field MRA in comparison with conventional DSA in 15 patients. Sequences acquired at 7T were TOF-MRA with 0.22 X 0.22 X 0.41 mm3 resolution and MPRAGE with 0.7 X 0.7 X 0.7 mm3 resolution. The relevant deeply seated collateral networks were classified into 2 categories and 6 pathways. A total of 100 collateral networks were detected on DSA; 106, on TOF-MRA; and 73, on MPRAGE. Delineation of deeply seated collateral networks was comparable between TOF-MRA and DSA. The authors demonstrate excellent delineation of 6 distinct deeply seated collateral network pathways in Moyamoya angiopathy.
- Relationship between Cough-Associated Changes in CSF Flow and Disease Severity in Chiari I Malformation: An Exploratory Study Using Real-Time MRI
The authors correlated disease severity in symptomatic patients with Chiari I malformation with cough-associated changes in CSF flow as measured with real-time MR imaging. Patients were classified into 2 groups by neurosurgeons blinded to MR imaging measurements: 1) nonspecific Chiari I malformation (5/13)—Chiari I malformation with nonspecific symptoms like non-cough-related or mild occasional cough-related headache, neck pain, dizziness, paresthesias, and/or trouble swallowing; 2) specific Chiari I malformation (8/13)—patients with Chiari I malformation with specific symptoms and/or objective findings like severe cough-related headache, myelopathy, syringomyelia, and muscle atrophy. There was a significant negative correlation between the percentage change in CSF stroke volume (resting to post coughing) and Chiari I malformation disease severity. They conclude that assessment of CSF flow response to a coughing challenge has the potential to become a valuable objective noninvasive test for clinical assessment of disease severity in patients with Chiari I malformation.
- Clinical Significance of Intraplaque Hemorrhage in Low- and High-Grade Basilar Artery Stenosis on High-Resolution MRI
Patients with basilar artery stenosis (n=126; 66 symptomatic and 60 asymptomatic) underwent high-resolution MR imaging. The relationship between imaging findings (intraplaque hemorrhage, contrast enhancement, degree of stenosis, minimal lumen area, and plaque burden) and symptoms was analyzed. Intraplaque hemorrhage was identified in 22 patients (17.5%), including 21 (31.8%) symptomatic patients and 1 (1.7%) asymptomatic patient. Multivariate analysis showed that intraplaque hemorrhage was the strongest independent marker of symptomatic status. Contrast enhancement was also independently associated with symptomatic status. The authors conclude that intraplaque hemorrhage is present in both low- and high-grade stenotic basilar artery plaques and is independently associated with symptomatic stroke status. Intraplaque hemorrhage may identify high-risk plaque and provide new insight into the management of patients with stroke without significant stenosis.
- Endovascular Treatment of Dural Arteriovenous Fistulas Using Transarterial Liquid Embolization in Combination with Transvenous Balloon-Assisted Protection of the Venous Sinus
The authors report their single-center experience in 22 patients with dural arteriovenous fistulas who were treated with transarterial liquid embolization in combination with transvenous balloon-assisted protection of the affected venous sinus. All patients were symptomatic, of whom 81.8% presented with tinnitus; 9.1%, with ocular symptoms; and 9.1%, with headache. Most fistulas were located at the transverse and/or sigmoid sinus. The most frequent fistula type was Cognard IIa+b (40.9%), followed by Cognard I (31.8%) and Cognard IIa (27.3%)/Borden I (59.1%), and Borden II (40.9%). The affected sinus could be preserved in all except for 1 patient in whom it was sacrificed in a second treatment procedure by coil embolization. The overall complete occlusion rate was 86.4%. The overall complication rate was 20%, with transient and permanent morbidity and mortality of 8%, 0%, and 0%, respectively. They conclude that transarterial liquid embolization of dural arteriovenous fistulas in combination with transvenous balloon-assisted protection of the venous sinus is feasible and safe.
