Spontaneous intracranial vertebral artery dissection with acute ischemic stroke: High-resolution magnetic resonance imaging findings

Abstract

Background Acute ischemic stroke (AIS) more frequently develops in patients with intracranial vertebral artery dissection (VAD) than extracranial VAD, and is associated with possible poor clinical outcomes. The aim of this study is to compare high-resolution magnetic resonance imaging (HR-MRI) findings and clinical features of VAD with and without AIS. Methods Twenty-nine lesions from 27 patients (15 male and 12 female patients; age range = 28-73 years) who underwent diffusion MRI and 3T HR-MRI within seven days were included. We classified VAD according to the presence of AIS lesions on diffusion MRI. Clinical features and HR-MRI findings (angiographic patterns, presence of double lumen sign, dissecting flap, posterior inferior cerebellar artery involvement, remodeling index, length of affected vessels, T1-signal intensity, area of intramural hematoma, and grades and patterns of vessel wall enhancement) were evaluated. Results Thirteen VADs with AIS and 16 without AIS were included. There were no significant differences in the clinical parameters (sex, age, risk factors, symptoms). More VADs with AIS presented as a steno-occlusive pattern than VADs without AIS. More VADs without AIS presented with aneurysmal dilation, larger mean remodeling index and longer mean length than VADs with AIS. Presence of intramural hematoma, T1-iso-signal intensity of intramural hematoma and contrast enhancement were significantly more common in VADs with AIS than without AIS. Conclusions Our study showed some differences in HR-MRI comparing intracranial VAD patients with and without AIS. Differing findings may facilitate a better understanding of intracranial VAD and risk assessment of AIS in these patients.

Keywords: Acute ischemic stroke (AIS); high-resolution magnetic resonance imaging (HR-MRI); intramural hematoma; vertebral artery dissection (VAD).

Figure 1.

HR-MRI findings of intracranial VAD with AIS. (a) Diffusion MRI demonstrates a focal acute infarction (arrow) involving right sided medulla. (b) TOF MR angiography reveals focal stenosis (arrow) at V4 segment of the right vertebral artery. (c) Axial pre-contrast T1-weighted MR image demonstrates crescentic T1 hyperintensity (arrow) at the stenotic segment, suggesting intramural hematoma. (d) Axial post-contrast T1-weighted image demonstrates perivascular enhancement (arrow) along the affected vessel. HR-MRI: high-resolution magnetic resonance imaging; VAD: vertebral artery dissection; AIS: acute ischemic stroke; TOF: time of flight; MR: magnetic resonance.

Figure 2.

HR-MRI findings of intracranial VAD without AIS. (a) TOF MR angiography demonstrate aneurysmal dilation (arrow) at V4 segment of the right vertebral artery. (b) Diffusion MRI reveals no evidence of diffusion restricted lesion involving brain parenchyma. (c) Axial pre-contrast T1-weighted image demonstrates intimal flap and hyperintense intramural hematoma (arrow). (d) Axial post-contrast T1-weighted image demonstrates perivascular enhancement (arrow) along the affected vessel. HR-MRI: high-resolution magnetic resonance imaging; VAD: vertebral artery dissection; AIS: acute ischemic stroke; TOF: time of flight; MR: magnetic resonance.