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In 15 patients,the diagnosis was primarily established with ultrasonography.Five patients with a dissection were referred for follow- up color-flow examinations.Six vertebral arteries were dissected at the origin or in the proximal V1 segment,one in the distal V2 segment,and one at the atlas loop.In contrast to other studies,the most frequent localization of the dissection in our patients was the region between V1 and V2 segments(n=16),where the most typical dissection site was the entrance of the artery into the transverse foramen of the C6 vertebra(n= 11).Typical ultrasonographic findings were irregular stenosis,dissecting membrane with true and false lumen,localized increase in diameter of the artery,pseudoaneurysm,intramural hematoma,and tapering stenosis with distal occlusion.In follow-up examination,a good regression of pathological findings was found in 17 dissections(70.8%).Two occlusions were completely recanalized.Extracranial vertebral artery dissections can be diagnosed noninvasively with duplex color-flow imaging.It is therefore a useful method for early diagnosis and follow-up examination. |
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