Semi-automatic computed tomography angiography quantification assessment is an alternative method to digital subtraction angiography in intracranial stenosis: a multicenter study.

Background: The recent randomized controlled trials studying intracranial atherosclerotic stenosis (ICAS) have used digital subtraction angiography (DSA) to quantify stenosis and enroll patients. However, some disadvantages of DSA such as invasive features, contrast agent overuse, and X-ray radiation overexposure, were not considered in these studies. This study aimed to explore whether computed tomography angiography (CTA) with semi-automatic analysis could be an alternative method to DSA in quantifying the absolute stenotic degree in clinical trials. Methods: Patients with 50-99% ICAS were consecutively screened, prospectively enrolled, and underwent CTA and DSA between March 2021 and December 2021 at 6 centers. This study was registered at www.chictr.org.cn (ChiCTR2100052925). The absolute stenotic degree of ICAS on CTA with semi-automatic analysis was calculated by several protocols using minimal/maximum/mean diameters of stenosis and reference site from a semi-automatic analysis software. Intraclass correlation coefficient (ICC) was used to evaluate the reliabilities of quantifying stenotic degree on CTA. The optimal protocol for quantifying ICAS on CTA was explored. The agreements of quantifying ICAS in calcified or non-calcified lesions and 50-69% or 70-99% stenosis on CTA and DSA were assessed. Results: A total of 191 participants (58.8±10.7 years; 148 men) with 202 lesions were enrolled. The optimal protocol for quantifying ICAS on CTA was calculated as (1 - the minimal diameter of stenosis/the mean diameter of reference) × 100% for its highest agreement with DSA [ICC, 0.955, 95% confidence interval (CI): 0.944-0.966, P<0.001]. Among the 202 lesions, 80.2% (162/202) exhibited severe stenosis on DSA. The accuracy of CTA in detecting severe ICAS was excellent (sensitivity =95.1%, positive predictive value =98.1%). The agreements between DSA and CTA in non-calcified lesions (ICC, 0.960 vs. 0.849) and severe stenosis (ICC, 0.918 vs. 0.841) were higher than those in calcified lesions and moderate stenosis. Conclusions: CTA with semi-automatic analysis demonstrated an excellent agreement with DSA in quantifying ICAS, making it promising to replace DSA for the measurement of absolute stenotic degree in clinical trials.

New Diffusion Abnormalities Following Endovascular Treatment for Intracranial Atherosclerosis.

Background There are limited data on new ischemic brain lesions after endovascular treatment for symptomatic intracranial atherosclerotic stenosis (ICAS). Purpose To investigate the (a) characteristics of new ischemic brain lesions at diffusion-weighted MRI (new diffusion abnormalities) after endovascular treatment, (b) characteristics between those treated with balloon angioplasty and stent placement procedures, and (c) predictors of new ischemic brain lesions. Materials and Methods Patients with symptomatic ICAS in whom maximum medical therapy failed were prospectively enrolled between April 2020 and July 2021 from a national stroke center and underwent endovascular treatment. All study participants underwent thin-section diffusion-weighted MRI (voxel size, 1.4 × 1.4 × 2 mm3 with no section gap) before and after treatment. The characteristics of new ischemic brain lesions were recorded. Multivariable logistic regression analysis was performed to determine potential predictors of new ischemic brain lesions. Results A total of 119 study participants (mean age, 59 years ± 11 [SD]; 81 men; 70 treated with balloon angioplasty and 49 with stent placement) were enrolled. Of the 119 participants, 77 (65%) had new ischemic brain lesions. Five of the 119 participants (4%) had symptomatic ischemic stroke. New ischemic brain lesions were located in (61%, 72 of 119) and/or beyond (35%, 41 of 119) the territory of the treated artery. Of the 77 participants with new ischemic brain lesions, 58 (75%) had lesions located in peripheral brain areas. There was no evidence of a difference in the frequency of new ischemic brain lesions between the balloon angioplasty and stent groups (60% vs 71%, P = .20). In adjusted models, cigarette smoking (odds ratio [OR], 3.6; 95% CI: 1.3, 9.7) and more than one operative attempt (OR, 2.9; 95% CI: 1.2, 7.0) were independent predictors of new ischemic brain lesions. Conclusion New ischemic brain lesions on diffusion-weighted MRI scans were common after endovascular treatment for symptomatic intracranial atherosclerotic stenosis, and occurrence may be associated with cigarette smoking and the number of operative attempts. Clinical trial registration no. ChiCTR2100052925 © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Russell in this issue.

Predictors of hyperperfusion syndrome after stent implantation in symptomatic intracranial atherosclerotic stenosis.

Background: Hyperperfusion syndrome (HPS) is a serious complication after stent implantation in symptomatic intracranial atherosclerotic stenosis (ICAS). This study aims to explore the predictive value of preprocedural computed tomography perfusion (CTP) for HPS after intracranial stenting. Methods: In this retrospective case-control study we collected data from consecutive patients from June 2012 to September 2019 who underwent stent implantation due to severe symptomatic ICAS. Patients who underwent CTP before the procedure were enrolled. CTP was postprocessed using the automated RAPID software to assess the preoperative cerebral perfusion. According to the presence or absence of HPS, the patients were classified into two groups: the HPS group and the non-HPS group. The baseline data, lesion characteristics, and preoperative CTP parameters between the two groups were compared. The receiver operating characteristic (ROC) curve analysis was performed to determine the optimal predictor of HPS. Results: Among the 170 eligible patients, 6 patients (3.53%) had HPS, including 3 who presented with intracranial hemorrhages (ICHs), 1 who had dysphoria, 1 who had delirium, and 1 who had a headache. There were no significant differences in baseline and lesion characteristics between the HPS and non-HPS groups. Compared with the non-HPS group, the HPS group had a significantly higher volume of time-to-maximum (Tmax) >4 s (429.5 vs. 93 mL; P=0.006) and Tmax >6 s (200 vs. 0 mL; P=0.003). The optimal volume threshold for maximizing sensitivity in predicting HPS was 65.5 mL with Tmax >4 s [area under the curve (AUC), 0.832; 95% confidence interval (CI): 0.650 to 1.000; P=0.006]. Conclusions: Tmax >4 s volume may be a predictor of HPS after stent implantation in symptomatic ICAS. Further prospective studies should be conducted to confirm our conclusion.

Association of residual stenosis after balloon angioplasty with vessel wall geometries in intracranial atherosclerosis.

BACKGROUND: Percutaneous transluminal balloon angioplasty (PTBA) may be an alternative treatment for patients with symptomatic intracranial atherosclerotic disease (ICAD) refractory to medical treatment. This study aimed to investigate the association of vessel wall geometric characteristics on high-resolution magnetic resonance vessel wall imaging (MR-VWI) with low residual stenosis in patients with ICAD after PTBA. METHODS: Patients with symptomatic ICAD who underwent PTBA were prospectively and consecutively enrolled. High-resolution MR-VWI was performed before the PTBA. Vessel wall geometries of the target artery, including normalized wall index (NWI: wall area/vessel area × 100%), normalized wall thickness index (NWTI: mean wall thickness/vessel radius × 100%), and remodeling index (RI) were evaluated. Low residual stenosis was defined as postprocedural stenosis degree ≤50%. Perioperative complications including symptomatic ischemic stroke/intracranial hemorrhage, death, and arterial dissection were recorded. The baseline characteristics, vessel wall geometries, and perioperative complications were compared between the patients with low residual stenosis and high residual stenosis. RESULTS: Among 60 patients prospectively enrolled, low residual stenosis was achieved in 46 participants (77%). Three patients (5%) suffered from symptomatic ischemic stroke within 30 days. Multivariable logistic regression showed that a lower NWI and lower NWTI were associated with low residual stenosis after PTBA (adjusted OR 0.57, 95% CI 0.35 to 0.94, p=0.027; and adjusted OR 0.88, 95% CI 0.80 to 0.98, p=0.015). CONCLUSIONS: Lower NWI and NWTI of the target artery on high-resolution MR-VWI were associated with low residual stenosis in patients with ICAD after PTBA.

Association of Perforator Stroke After Basilar Artery Stenting With Negative Remodeling.

Background and Purpose- We try to evaluate whether plaque features and perforator stroke after intracranial stenting is associated with the arterial remodeling patterns in patients with severe basilar artery stenosis. Methods- We studied patients with symptomatic intracranial arterial stenosis who underwent high-resolution magnetic resonance imaging from September 2014 to January 2017. Among them, patients with basilar artery stenosis underwent angioplasty and stenting were recruited. Arterial remodeling patterns were divided into negative or nonnegative remodeling. Plaque features were investigated by high-resolution magnetic resonance imaging, which includes plaque distribution, intraplaque hemorrhage, calcification, as well as enhancement patterns. Incidence of perforator strokes after intracranial stenting was recorded. Plaque features and incidence of poststenting perforator stroke were compared between negative and nonnegative remodeling. Results- Two hundred ninety-eight consecutive patients were enrolled. Among them, 30 patients fulfilled the inclusion criteria. There were 11 patients (36.7%) with negative remodeling and 19 (63.3%) with nonnegative remodeling. Twenty-six patients (86.7%) had diffuse distribution, 5 patients (16.7%) had intraplaque hemorrhage, 2 patients (6.7%) had calcification, and 17 patients (65.4%) had enhancement. Three patients had perforator stroke after stenting. Plaque features were similar between negative and nonnegative remodeling groups. Patients with negative remodeling were more likely to have perforator stroke after stenting comparing with patients with nonnegative remodeling (27.3% versus 0%, P=0.041). Conclusions- Perforator stroke after basilar artery stenting may be related to negative remodeling on high-resolution magnetic resonance imaging. The finding needs to be confirmed in future studies. Clinical Trial Registration- URL: https://www.clinicaltrials.gov . Unique identifier: NCT02705599.