MAGNETIC-RESONANCE ANGIOGRAPHIC AND CLINICAL-FEATURES OF EXTRACRANIALVERTEBRAL ARTERY DISSECTION

Objectives-Clinical data and neuroradiological findings of 19 patients with 20 vertebral artery dissections were analysed to describe the fe atures of time of flight magnetic resonance angiography (MRA) for the diagnosis and follow up of this vascular disorder. Methods-All patient s underwent a combined MRI and MRA protocol with 1.5 T scanners, using a three dimensional flow compensated gradient echo sequence for MRA, Duplex sonography was performed on all patients and selective angiogra phy was available from 17 vertebral artery dissections. Results-MRI sh owed ischaemic lesions of the brain in 18 of 19 patients (95%). in the acute and subacute stage, MRA detected signal abnormalities within th e dissected vertebral artery in 94% (16/17) and MRI was specific for a dissection in 29% (5/17). Sensitivity of selective angiography was 10 0% and specificity was 35% (6/17). Combination of the results of bath methods increased the specificity to 50%. Duplex sonography was sensit ive in 79% (15/19), but lacked specific results. Follow up magnetic re sonance in 16 patients showed recanalisation of the dissected vessel i n 10 (63%), persistent occlusion in five (31%), and a dissecting aneur ysm in one (6%) patient. Conclusions-Magnetic resonance improves the t riage for selective angiography and discloses complementary informatio n for the diagnosis of vertebral artery dissection. if magnetic resona nce identifies a double lumen or a mural haematoma with a stenosis or aneurysmal dilatation, invasive procedures can be omitted.