Evaluation of the vertebrobasilar-posterior system by transcranial color duplex sonography in adults

Abstract

Background and Purpose: The transcranial color duplex sonography technique was applied to the vertebrobasilar-posterior system to provide normal data for clinical application. Methods: The intracranial posterior circulation was studied in 49 healthy volunteers (mean±SD age, 35±12 years) by a transcranial and suboccipital approach with a 2.0-MHz sector transducer of a computed sonography system. Results: The posterior cerebral artery and the vertebrobasilar system were depicted clearly in the color Doppler mode. Pulsed Doppler signals could be recorded in the posterior cerebral (100%), basilar (92%), and vertebral arteries (89%). The following normal values were provided for all vessels: systolic peak, end-diastolic maximum, time-averaged, and time-averaged maximum velocities; resistance and pulsatility indexes; and a spectral broadening index. Mean±SD values were 45.9±9.6, 45.5±10.8, and 39.2±10.6 cm/sec for time-averaged maximum velocity, and 28.3±6.5, 30.6±7.2, and 24.7±8.4 cm/sec for time-averaged velocity in the posterior cerebral, basilar, and vertebral arteries, respectively. In a reproducibility study, duplex measurements of the posterior cerebral arteries were repeated in 27 subjects. The correlation between the two examiners was high (r=0.56, p<0.0001 for time-averaged maximum velocity). Conclusions: Color duplex sonography of the vertebrobasilar-posterior system is a new, noninvasive, bedside investigative technique. It permits visualization of artery flow in real time, relating these to adjacent brain and cranial structures, as well as angle-corrected duplex measurement of “true” flow velocities at defined sites of the vessels. Thus, it will open new diagnostic possibilities in disorders of the posterior circulation. © 1992 American Heart Association, Inc.