Transcranial color-coded sonography of the basal cerebral circulation. Reference data from 115 volunteers.

BACKGROUND AND PURPOSE Transcranial color-coded sonography is a new development in noninvasive cerebral vascular imaging. Reference data using this technique are described. METHODS Blood velocities and pulsatility and resistance indices were determined in the anterior cerebral, middle cerebral, posterior cerebral, vertebral, and basilar arteries in 115 volunteers after correction for the angle of insonation. RESULTS Of 1265 basal arterial segments, 1053 were insonated (83%). The vertebral (98%), basilar (92%), middle cerebral (84%), and posterior (P1) cerebral arteries (84%) were the most successfully insonated, with the anterior (73%) and posterior (P2) cerebral arteries (72%) the least successfully insonated. Mean and end-diastolic blood velocities decreased significantly with age in all vessels (middle cerebral artery mean velocity: 20 to 39 years, 74 cm/s [71-76]; > 60 years, 58 cm/s [55-61], P < .0001; mean with 95% confidence intervals), and peak systolic velocity decreased significantly except in the posterior (P2) cerebral artery. Blood velocities were higher in women except in the > 60-year group. Velocities showed the least interhemispheric asymmetry in the middle cerebral artery (r = .85 and r = .83, peak and mean velocities, respectively) and the greatest asymmetry in the posterior (P2) cerebral artery (r = .58 and r = .59, peak and mean velocities, respectively). Pulsatility and resistance indices increased significantly with age in all vessels (middle cerebral artery pulsatility index: 20 to 39 years, 0.84 [0.82-0.87], > 60 years, 0.97 [0.93-1.02], P < .0001; middle cerebral artery resistance index: 20 to 39 years, 0.55 [0.54-0.56], > 60 years, 0.62 [0.60-0.64], P < .0001). CONCLUSIONS Transcranial color-coded sonography can image the basal cerebral arteries and distinguish vertebral from basilar artery flow and enables pulsed Doppler interrogation with correction for the angle of insonation.