Visualization of the basilar artery by transcranial color-coded duplex sonography - Comparison with postmortem results

Background and Purpose-Transcranial color-coded sonography (TCCS) via the s uboccipital approach allows direct and continuous Visualization of the basi lar artery (BA). In this study, we intended to evaluate the ability of nati ve TCCS in visualizing the length of the BA by means of a comparison with p ostmortem measurements. Methods-The BA was prospectively studied by TCCS shortly before death (medi an 3 days) in 46 moribund neurological patients (mean+/-SD age 71.1+/-13.1 years). The length of the BA was determined by measuring the distance betwe en the vertebrobasilar junction and the deepest available flow signal in th e top of the BA. During autopsy, photos of the vertebrobasilar system were taken to evaluate the true anatomic length and variations of the course of BA in situ, eg, straight, curved, or S-shaped, Results-Comparison of the in vivo ultrasound measurements of BA length and postmortem data was possible in 44 of 46 cases. In the 2 remaining patients , the BA was occluded, The mean insonation depth of the vertebrobasilar jun ction was found at 66.9+/-7.1 mm, The mean BA length was 21.5+/-6.8 mm by c olor-coded duplex and 32.9+/-6 mm anatomically (P<0.0001). The mean differe nce between color mode and anatomic findings was 11.3+/-6.4 mm in the case of a straight BA (35 cases) and 16.3+/-4.8 mm in an anatomically tortuous c ourse of the BA (9 cases). Conclusions-Color duplex imaging enables correct visualization of the proxi mal two thirds of the BA, but only exceptionally of its distal one third. A tortuous course of the BA leads to an underestimation of its anatomic leng th.