A Dilated Surface Appearance on Basiparallel Anatomic Scanning–Magnetic Resonance Imaging Is a Useful Tool for the Diagnosis of Spontaneous Vertebral Artery Dissection in Lateral Medullary Infarction

Abstract

Spontaneous dissection of the vertebral artery (VA) is a major vascular lesion causing lateral medullary infarction (LMI). A dilated surface appearance of the VA is a feature of VA dissection and can be observed on basiparallel anatomic scanning (BPAS)-magnetic resonance imaging (MRI). The aim of this study was to validate BPAS-MRI in the diagnosis of VA dissection in patients with LMI. The subjects of the present study were 41 consecutive patients with LMI within 7days of onset. The diagnosis of VA dissection was made with the clinical criteria-based diagnosis. Percent (%) dilatation of the VA on BPAS-MRI was calculated by comparing the maximum surface diameter of the intracranial VA to the diameter of the distal normal surface of the VA. Fourteen patients (34%) were diagnosed with VA dissection. The optimal cutoff % dilatation of the VA for dissection was more than 169%. The sensitivity and specificity of % dilatation of VA more than 169% and aneurysmal dilatation, stenosis, or occlusion on magnetic resonance angiography (MRA) for VA dissection were 92.9% and 81.5%, respectively. BPAS-MRI combined with time-of-flight-MRA is a useful tool for the diagnosis of VA dissection in patients with acute LMI.