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Updated: May 16, 2026

Transient Middle Cerebral Artery Occlusion Model of Stroke
Published on: August 11, 2023
ASFNR Current State of Practice in Neuroimaging of Distal Medium Vessel Occlusion Stroke
Aakanksha Sriwastwa1, Jason W Allen2, Rajan Jain2
1From the Department of Radiology (A.S., A.S.V.), Neurology (Y.N.A.), College of Medicine, University of Cincinnati, Cincinnati, Ohio, USA; Department of Radiology (J.W.A.), Indiana University School of Medicine, Indianapolis, USA; Department of Radiology (R.J.), New York University Grossman School of Medicine, New York, USA; Department of Radiology (G.V.S.), University of Michigan, Ann Arbor, USA; Department of Neuroradiology (H.A.S.), The University of Texas MD Anderson Center, Houston, Texas, USA; Department of Radiology (D.A.L.), Division of Neuroradiology, West Virginia University, Morgantown, West Virginia, USA; Department of Radiology (T.D.F.), Neuroendovascular Program (A.A.D.), University Medical Center Münster, Münster, Germany; Department of Interventional Neuroradiology (J.J.H.), Stanford Medical Center, Palo Alto, California; Department of Neurology (S.M.), University of Maryland Medical Center, Baltimore, Maryland, USA; Neuroendovascular Program, Massachusetts General Hospital & Brigham and Women's Hospital, Harvard University, Boston, Massachusetts, USA; Stanford Stroke Center (A.G.), Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California, USA; University of Calgary (J.O.), Department of Clinical Neuroscience; University Drive NW, Calgary, Alberta, Canada T2N 5B3 and Department of Radiology (V.S.Y.), Division of Neuroradiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA. sriwasaa@ucmail.uc.edu.
Background:
Distal medium vessel occlusions (DMVO) constitute approximately 25%-40% of acute ischemic stroke. These potentially disabling strokes remain diagnostically challenging due to vessel caliber, tortuosity, and low sensitivity of standard CT angiography.
Recent Developments:
Multiple recent multicenter randomized controlled trials (DISTAL, ESCAPE-MeVO, DISCOUNT, ORIENTAL-MeVO and DISTALS) showed overall heterogenous results of mechanical thrombectomy (MT) over best medical treatment to treat DMVO, with higher symptomatic intracranial hemorrhage rates in the MT arm.
Purpose:
Summarize current evidence and provide a "state of practice" guide for radiologists on DMVO detection, workflow standardization, triage, and imaging-based prognostication.
Key Points:
Optimized CTA (including multiphase), CT Perfusion (territorial Tmax), and MRI DWI/SWI improve diagnostic confidence for DMVO. Certain perfusion parameters indicative of collateral status, for instance, rCBV index and hypoperfusion intensity ratio, have prognostic value. Structured reporting of important positive and negative radiologic findings can guide neurologic triage despite neutral trials.
Conclusion:
Radiologists play a central role in DMVO diagnosis and prognostication. Standardized imaging workflows are essential in the post-trial landscape.