Difference In Imaging Biomarkers Between Transient And Permanent Neurological Deficits After Endovascular Treatment Of Cerebrovascular Aneurysms

OBJECTIVE The literature suggests that blood-brain barrier disruption (BBBD) plays a significant role in the develop- ment of neurological events in patients with diffusion-weighted imaging (DWI) that is negative for lesions. In this prospective, single-center cohort study, the authors compared the imaging characteristics of patients suffering transient neurological events (TNEs) with those in patients suffering permanent neurological events (PNEs) after having undergone elective embolization of unruptured intracranial aneurysms. METHODS This prospective cohort study was conducted between July 2016 and June 2019. Inclusion criteria were adults undergoing elective neuroendovascular procedures and the absence of contraindications to MRI. All subjects underwent brain MRI including postcontrast FLAIR (pcFLAIR) sequences for evaluation of BBBD within 24 hours post procedure. RESULTS In total, 128 patients harboring 133 unruptured aneurysms were enrolled, 109 of whom (85.2%) showed some degree of BBBD on pcFLAIR MRI and 50 of whom (39.1%) suffered an ischemic insult per DWI. In total, 23 patients (18%) suffered neurological complications, 16 of which (12.5%) were TNEs and 7 of which (5.5%) were PNEs. The median extent of BBBD was focal in asymptomatic patients as compared to hemispheric and lobar in the TNE and PNE groups, respectively (p < 0.001). The American Society of Anesthesiologists physical status classification predicted the extent of BBBD (p = 0.046). Lesions on DWI were noted in 34 asymptomatic patients (32.4%) compared to 9 patients (56.3%) with TNEs and all 7 patients (100%) with PNEs (p < 0.001). The median number of DWI lesions was 0 (range 0-18 lesions) in the asymptomatic group compared to 1.5 (range 0-8 lesions) and 8 (range 1-13 lesions) in the TNE and PNE groups, respectively (p < 0.001). Smoking (p = 0.008), older age (p = 0.002), and longer surgery (p = 0.006) were positively associated with the number of lesions on DWI. On multivariate analysis, intraarterial verapamil (p = 0.02, OR 8.01, 95% CI 1.35-47.43) and extent of BBBD (p < 0.001, OR 58.58, 95% CI 9.48-361.84) were positively associated with the development of TNEs, while intravenous infusion of midazolam during surgery (p = 0.02, OR 6.03, 95% CI 1.29-28.20) was negatively associated. An increased number of lesions on DWI was the only significant predictor for the development of PNEs (p < 0.001, OR 49.85, 95% CI 5.56-447.10). CONCLUSIONS An increasing extent of BBBD was associated with the development of TNEs, whereas an increasing number of lesions on DWI was significantly associated with the development of PNEs. BBBD imaging using pcFLAIR may serve as a valuable biomarker for detecting subtle cerebral ischemia and stratifying the risk for ischemic events.