Vessel Wall Magnetic Resonance Imaging in Cerebrovascular Diseases

Abstract

Cerebrovascular diseases are a leading cause of disability and death worldwide. The definition of stroke etiology is mandatory to predict outcome and guide therapeutic decisions. The diagnosis of pathological processes involving intracranial arteries is especially challenging, and the visualization of intracranial arteries' vessel walls is not possible with routine imaging techniques. Vessel wall magnetic resonance imaging (VW-MRI) uses high-resolution, multiparametric MRI sequences to directly visualize intracranial arteries walls and their pathological alterations, allowing a better characterization of their pathology. VW-MRI demonstrated a wide range of clinical applications in acute cerebrovascular disease. Above all, it can be of great utility in the differential diagnosis of atherosclerotic and non-atherosclerotic intracranial vasculopathies. Additionally, it can be useful in the risk stratification of intracranial atherosclerotic lesions and to assess the risk of rupture of intracranial aneurysms. Recent advances in MRI technology made it more available, but larger studies are still needed to maximize its use in daily clinical practice.

Keywords: atherosclerosis; cerebrovascular disease; dissection; intracranial vasculopathy; stroke; vasculitis; vessel wall MRI.

Figure 1

VWMRI findings in CNS vasculopathies. TOF-MRA of a patient with PACNS and recurrent ischemic strokes shows stenosis of M1 segment of MCA (panel (A), white arrow) with corresponding vivid concentric enhancement of arterial walls in post contrast in T1W black blood sequence (panel (B), white arrows) (* contralateral normal M1 segment). After treatment with intravenous high dose methylprednisolone and cyclophosphamide bolus, contrast enhancement was markedly reduced (panel (D), white arrows) with stable MRA findings (panel (C), white arrow). The patients had no recurrence of stroke during follow-up. MRA and VW-MRI findings of a patient with COVID19-associated cryptogenic ischemic stroke demonstrated stenosis of ACA (panel (E), white arrow) with corresponding contrast enhancement on VW-MRI (panel (F), white arrow). MRA of a patient with syphilitic CNS vasculitis revealed multifocal arterial lumen irregularities (panel (G), white arrows) and VW-MRI demonstrated multifocal enhancement of correspondent MCA segments (panel (H), white arrows). CNS: central nervous system; TOF: time of flight; MRA: magnetic resonance angiography; PACNS: primary angiitis of the CNS; MCA: middle cerebral artery; T1W: T1 weighted; VWMRI: vessel wall MRI; COVID19: Coronavirus disease 2019.