Carotid Ultrasonography vs. CT or MR Angiography in the Diagnosis of the Stenosis of Vertebral Artery Origins

ABSTRACT

BACKGROUND: The origin of the vertebral artery (VA) is prone to be misinterpreted as having focal stenosis on computed tomography angiography (CTA) or magnetic resonance angiography (MRA) due to artifacts. Ultrasonography may be a valuable technique to reveal stenosis of the VA origin. We compared the findings for the VA origin from CTA or MRA with those from ultrasonotraphy. METHODS: We consecutively enrolled patients who underwent angiography (CTA or MRA) and carotid ultrasonography. The V2 and V1 portions of the VA were insonated to evaluate the presence of plaque or steno-occlusion. CTA or MRA data were evaluated. Stenosis or occlusion of the VA origin was categorized as present or absent. The results from the two methods were compared. RESULTS: The mean age of the 73 investigated patients was 61.1 years, and 46 (63.0%) of them were male. Among the 22 patients with steno-occlusion of the right VA on CTA or MRA, only six had stenosis on ultrasonography. Regarding the left VA, only four patients among 16 who showed steno-occlusion on CTA or MRA had steno-occlusion on ultrasonography. The level of agreement between the two methods was 82.2% on the left side and 75.3% on the right side. There were no clinical differences between the patients with and without false-positive results on CTA or MRA. CONCLUSIONS: In 16.4% (left) and 21.9% (right) of all patients, lumens with steno-occlusions observed on CTA or MRA were revealed as normal on ultrasonography. The diagnosis of VA origins could be improved by applying these two methods complementarily.