Association and Discordance Between Magnetic Resonance Angiography and Three-Dimensional Vessel Wall Imaging in Detecting Intracranial Atherosclerosis

Background: Evaluation of intracranial atherosclerosis currently relies on angiography techniques to detect luminal stenosis, among which 3D time-of-flight (TOF) MRA is most widely used. Recently, 3D vessel wall (VW) MRI has allowed direct plaque visualization in major intracranial arteries. Purpose: We sought to study the association between luminal stenosis on TOF-MRA and plaque on VW-MRI in major intracranial arteries. Methods: Patients with recent cerebral ischemic events and without cardioembolic or rare etiologies were scanned with intracranial TOF-MRA (resolution: 0.53x0.83x1.4 mm3) and VW-MRI (0.8x0.8x0.8 mm3). Eleven segments were evaluated, including cavernous and supraclinoid internal carotid artery (ICA), anterior cerebral artery (A1), middle cerebral artery (M1), basilar artery, and posterior cerebral artery (P1). TOF-MRA and VW-MRI were analyzed blinded to each other and clinical data. Luminal stenosis on TOF-MRA was categorized as mild (1-49%), moderate (50-69%), severe (70-99% or flow void...