- Comparison of Enhancement of the Vestibular Perilymph between Variable and Constant Flip Angle–Delayed 3D-FLAIR Sequences in Menière Disease
The authors compared the degree of perilymphatic enhancement and the detection rate of endolymphatic hydrops using constant and variable flip angle sequences in 16 patients with 3T MR imaging. Both for symptomatic and asymptomatic ears, the median signal intensity ratio was significantly higher with the constant flip angle than with the heavily-T2 variable flip angle. Cochlear blood-labyrinth barrier impairment was observed in 4/18 symptomatic ears with the heavily-T2 variable flip angle versus 8/19 with constant flip angle sequences. They conclude that 3D-FLAIR constant flip angle sequences provide a higher signal intensity ratio and are superior to heavily-T2 variable flip angle sequences in reliably evaluating the cochlear blood-labyrinth barrier impairment.
- CT Angiography in Evaluating Large-Vessel Occlusion in Acute Anterior Circulation Ischemic Stroke: Factors Associated with Diagnostic Error in Clinical Practice
This study included 520 consecutive patients with a clinical diagnosis of acute ischemic stroke (49.4% men; mean age, 72 years) who underwent CTA to evaluate large-vessel occlusion of the proximal anterior circulation. CTA scans were retrospectively reviewed by a consensus panel of 2 neuroradiologists. The prevalence of large-vessel occlusion was 16% (84/520 patients); 20% (17/84) of large-vessel occlusions were missed atthe initial CTA evaluation. In multivariate analysis, non-neuroradiologists were more likely to miss large-vessel occlusion compared with neuroradiologists, and occlusions of the M2 segment were more likely to be missed compared with occlusions of the distal internal carotid artery and/or M1 segment. Calcified emboli were present in 4 of 17 (24%) initially missed or misinterpreted large-vessel occlusions.
- Reliability of CT Angiography in Cerebral Vasospasm: A Systematic Review of the Literature and an Inter- and Intraobserver Study
In Part I of this study, articles reporting the reliability of CTA up to May 2018 were systematically searched and evaluated. In Part II, 11 raters independently graded 17 arterial segments in each of 50 patients with SAH for the presence of vasospasm using a 4-category scale. Raters were additionally asked to judge the presence of any moderate/severe vasospasm and whether findings would justify augmentation of medical treatment or conventional angiography ± balloon angioplasty. The systematic review revealed few studies with heterogeneous vasospasm definitions. In Part II, the authors found interrater reliability to be moderate at best (ϰ > 0.6), even when results were stratified according to specialty and experience. They conclude that the diagnosis of vasospasm using CTA alone was not sufficiently repeatable among observers to support its general use to guide decisions in the clinical management of patients with SAH.
- SWAN-Venule: An Optimized MRI Technique to Detect the Central Vein Sign in MS Plaques
Multiple sclerosis lesions develop around small veins that are radiologically described as the so-called central vein sign. With 7T MR imaging and magnetic susceptibility-based sequences, the central vein sign has been observed in 80%–100% of MS lesions in patients' brains. However, a lower proportion ∼50% has been reported at 3T using SWAN. The authors' aim was to assess a modified version of SWAN optimized at 3T for sensitive detection of the central vein sign. Thirty subjects with MS were scanned on a 3T clinical MR imaging system. 3D T2-weighted FLAIR and optimized 3D SWAN, called SWAN-venule, were acquired after injection of a gadolinium-based contrast agent. Overall, the central vein sign was detected in 86% of the white matter lesions (periventricular, 89%; deep white matter, 95%; and juxtacortical, 78%). The SWAN-venule technique is an optimized MR imaging sequence for highly sensitive detection of the central vein sign in MS brain lesions.
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