Disrupted Brain Functional Status in Patients with Reversible Cerebral Vasoconstriction Syndrome

Abstract

ObjectivesThe aim of this study was to investigate the functional networks in subjects with reversible cerebral vasoconstriction syndrome (RCVS) using resting‐state functional magnetic resonance imaging (rs‐fMRI).MethodsWe prospectively recruited patients with RCVS and healthy controls (HCs) between February 2017 and April 2021. The rs‐fMRI data were analyzed using graph theory methods. We compared node‐based global and regional topological metrics (Bundle 1) and network‐based intranetwork and internetwork connectivity (Bundle 2) between RCVS patients and HCs. We also explored the associations of clinical and vascular (ie, the Lindegaard index, LI) parameters with significant rs‐fMRI metrics.ResultsA total of 104 RCVS patients and 93 HCs were included in the final analysis. We identified significantly decreased local efficiency of the left dorsal anterior insula (dAI; p = 0.0005) in RCVS patients within 30 days after disease onset as compared to HCs, which improved 1 month later. RCVS patients also had increased global efficiency (p = 0.009) and decreased average degree centrality (p = 0.045), clustering coefficient (p = 0.033), and assortativity values (p = 0.003) in node‐based analysis. In addition, patients with RCVS had increased internetwork connectivity of the default mode network (DMN) with the salience (p = 0.027) and dorsal attention (p = 0.016) networks. Significant correlations between LI and regional local efficiency in left dAI (rs = −0.418, p = 0.042) was demonstrated.InterpretationThe significantly lower local efficiency of the left dAI, suggestive of impaired central autonomic modulation, was negatively correlated with vasoconstriction severity, which is highly plausible for the pathogenesis of RCVS. ANN NEUROL 2023

Dynamic changes in glymphatic function in reversible cerebral vasoconstriction syndrome

“…The LI was used as a vasoconstriction severity indicator in RCVS [ 3 , 38 ]. Although its correlation with DTI-ALPS index was not significant ( p = 0.446), it was important to evaluate the time-trends of vasoconstriction severity with DTI-ALPS dynamics throughout the disease course (Supplementary Figure 5 in Additional file 1 ).…”

“…In our practice, all RCVS subjects were treated with nimodipine upon diagnosis since it was not ethical to leave the patients untreated [ 37 ]. Therefore, despite the fact that the DTI-ALPS index values in acute RCVS between subjects with and without nimodipine were similar and we monitored all the subjects closely to avoid any hypotensive episodes with systolic blood pressure < 100 mmHg, [ 38 ] the effects of nimodipine on the hemodynamics and glymphatics may still exist. In fact, some studies have indicated that the nimodipine could increase glymphatic flow [ 40 , 41 ].…”

“…The dosage was meticulously adjusted by close blood pressure monitoring to avoid systolic blood pressure < 100 mmHg. [ 38 ] Subjects under medical treatments other than nimodipine were not enrolled and we did not administrate medications other than nimodipine during the disease course. Given the varied timepoints of patient enrollment relative to disease onset, the diffusion tensor imaging (DTI) for most patients was conducted concurrently with the diagnostic MRI, while for others it was performed after diagnostic ascertainment.…”