Clinical and neuroradiological features of intracranial vertebrobasilar artery dissection

Background and Purpose-We sought to determine the clinical and neuroradiolo gical features of intracranial vertebrobasilar artery dissection. Methods-The clinical features and MR findings of 31 patients (20 men and 11 women) with intracranial vertebrobasilar artery dissections confirmed by v ertebral angiography were analyzed retrospectively. The vertebral angiograp hy revealed the double lumen sign in 11 patients (13 arteries) and the pear l and string sign in 20 patients (28 arteries). Results-The patients ranged in age from 25 to 82 years (mean, 54.8 years). Clinical symptoms due to ischemic cerebellar and/or brain stem lesions were common, but in 3 cases the dissections were discovered incidentally while an unrelated disorder was investigated. Headache, which has been emphasized as the only specific clinical sign of vertebrobasilar artery dissection, w as found in 55% of the patients. Intramural hematoma on T1-weighted images has been emphasized as a specific MR finding. The positive rate of intramur al hematoma was 32%. Double lumen on 3-dimensional (3-D) spoiled gradient-r ecalled acquisition (SPGR) images after the injection of contrast medium wa s identified in 87% of the patients. The 3-D SPGR imaging method is conside red useful fur the screening of vertebrobasilar artery dissection. Conclusions-Intracranial vertebrobasilar artery dissection is probably much more frequent than previously considered. Such patients may present no or only minor symptoms. Neuroradiological screening for posterior circulation requires MR examinations, including contrast-enhanced 3-D SPGR. Angiography may be necessary for the definite diagnosis of intracranial vertebrobasila r artery dissection because the sensitivity of the finding of intramural he matoma is not satisfactory.