Vertebral artery dissections: follow-up with contrast-enhanced 3D magneticresonance angiography.

Vertebral artery dissection is a frequent cause of ischemic stroke in young adults but time course of VA dissections remains poorly documented. Angiog raphy was considered as the gold standard for the diagnosis. Recently, non- invasive methods have been developed such as helical CT and magnetic resona nce angiography. The purpose of the study was to assess the reliability of a gadolinium-enhanced fast three dimensional (3D) magnetic resonance (MR) a ngiographic sequence to image vertebral arteries and to assess the long-ter m follow-up of vertebral artery (VA) dissections. Sixteen consecutive patie nts with 18 angiographically documented VA dissections were followed-up by gadolinium-enhanced 30 MR angiography and cervical TI-weighted MR imaging a t a median delay of 22 months. Ten patients had MR imaging scan at the acut e stage as well and nine had early follow-up angiography at a median delay of 3 months. MR angiography was evaluated in a consensus manner including i mage quality, presence of residual stenosis, luminal irregularities and occ lusion. All patients clinically improved. Ten of II stenostic dissections r eturned to normality whereas one stenotic dissection progressed to occlusio n. Two pseudoaneurysms detected on the initial angiography resolved spontan eously, one appeared only on a delayed MR angiographic scan and one was det ected on early MR angiograms and finally resolved on a late one. Of the sev en initially occluded VAs, five reopened with a hairline residual lumen in three. Contrast MR angiography is an interesting tool to assess the late co urse of VA dissections. Most lesions resolved spontaneously but persisting occlusion or pseudoaneurysm may be found in long term follow-up.