Contrast‐Enhanced 3T Vessel Wall Imaging for Symptomatic Intracranial Atherosclerotic Stenosis: Value of Pituitary Stalk Reference

ABSTRACT Background Three‐dimensional vessel wall imaging (VWI) using 3T MRI enables detailed assessment of intracranial atherosclerotic stenosis (ICAS), but the optimal reference tissue and its clinical utility remain unclear. This study aimed to identify the most suitable reference tissue for contrast‐enhanced (CE) VWI and to clarify imaging differences between symptomatic and asymptomatic ICAS. Methods We retrospectively analyzed 45 patients with 56 ICAS lesions undergoing CE‐VWI between April 2016 and August 2024. Exclusion criteria included complete occlusion, non‐atherosclerotic vascular disease, embolism, ≥ 50% ipsilateral cervical internal carotid artery (ICA) stenosis, and poor image quality. Lesions imaged within 3 months of transient ischemic attack (TIA) or infarction were defined as symptomatic; those imaged > 3 months post‐onset or without ischemic history were classified as asymptomatic. VWI sequences included 3D time ‐of‐flight MR angiography (TOF‐MRA), non‐contrast‐enhanced (non‐CE), and CE T1‐weighted imaging (T1WI) using improved motion‐sensitized driven equilibrium‐3D turbo spin echo (TSE). Signal intensity ratios of the vessel wall to surrounding tissues (brain parenchyma, gray matter, optic chiasm, muscle, and pituitary stalk) were calculated, along with wall thickness at the stenotic site. Results Among 56 lesions, 24 were symptomatic and 18 asymptomatic. Baseline characteristics were similar between groups. The vessel wall intensity ratio was significantly higher in symptomatic lesions across all reference tissues in both non‐CE and CE‐VWI. The ratio using the pituitary stalk in CE‐VWI showed the best discriminatory performance. Conclusion CE‐VWI using the pituitary stalk as a reference tissue provides high discriminatory value in differentiating symptomatic from asymptomatic ICAS, supporting imaging‐based diagnosis of relevant ICAS.