- 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.
- MRI Vessel Wall Imaging after Intra-Arterial Treatment for Acute Ischemic Stroke
The authors compared vessel wall enhancement after intra-arterial thrombosuction with that in patients not treated by thrombosuction in a group of 49subjects with ischemic stroke with 7T MR imaging within 3 months after symptom onset. In the intra-arterial treatment group, 11 of 14 patients (79%) showed vessel wall enhancement compared with 17 of 35 patients without intra-arterial treatment (49%). In the intra-arterial treatment group, more enhancing foci were detected on the ipsilateral side compared with the contralateral side. They conclude that patients with intra-arterial treatment by means of thrombosuction showed more (concentric) enhancing foci of the vessel wall ipsilateral compared with contralateral to the treated artery than the patients without intra-arterial treatment, suggesting reactive changes of the vessel wall.
- 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.