Vessel Wall Imaging in Cryptogenic Stroke

• Authors: Bhagya Sannananja, Emory University; Chengcheng Zhu, University of Washington; Mahmud Mossa-Basha, University of Washington
• Journal Title: Radiologic Clinics of North America
• Volume: Volume 61, Number 3
• Publisher: Elsevier | 2023-02-20, Pages 491-500
• Type of Work: Article | Post-print: After Peer Review
• Publisher DOI: http://doi.org/10.1016/j.rcl.2023.01.006
• Subjects: Health Sciences, Medicine and Surgery
• Keywords: Stroke; Cryptogenic stroke; embolic stroke of undetermined source

Abstract

Stroke is one of the leading causes of death and long-term disability worldwide.1 The Trial of Org 10172 in Acute Stroke Treatment (TOAST), first published in 1993, classified ischemic strokes into 5 subtypes based on etiology: large-artery atherosclerosis, cardioembolic disease, small-vessel disease, other determined etiology, and in 10% to 40%, no etiology can be identified after a standard diagnostic evaluation, termed cryptogenic stroke (CS).2 CS constitutes a significant percentage of total stroke cases and since the etiology remains unknown, no evidence-based targeted therapy can be instituted, which puts them at higher risk of recurrent stroke. Multiple additional etiologic classification systems for IS have been proposed including embolic stroke of undetermined source (ESUS). ESUS includes non-lacunar infarcts without atherosclerosis causing ≥50% stenosis in arteries supplying the ischemic territory, no cardioembolic source or any other etiology,3 and accounts for 17% of all IS. Occult atrial fibrillation was thought to represent the primary etiology for ESUS, however, there is evidence to suggest ESUS is a heterogeneous group with multiple potential etiologies beyond atrial fibrillation, including <50%-stenotic atherosclerosis affecting the aortic arch, cervical, and intracranial arteries. In current practice, luminal imaging such as computed tomography angiography (CTA), MRA or digital subtraction angiography (DSA) are used for stroke etiology, but provide little information of vessel wall abnormalities, whereas vessel wall imaging (VWI) directly visualizes the vessel wall and has shown its value in intra- and extra-cranial vasculopathy assessment.4,5 In this article, we review the role of VWI in the diagnostic workup of CS.