A validation study on the intraobserver reproducibility of transcranial color-coded duplex sonography velocity measurements.

Transcranial color-coded duplex sonography (TCCD) is a new method for the measurement of angle-corrected intracranial blood velocities. The insonation angle represents the most important technical variable affecting Doppler velocimetry. The present study was designed to evaluate the intraobserver reproducibility of TCCD for repeated examinations of blood velocity in the anterior, middle and posterior cerebral, basilar and vertebral arteries. Three examinations were performed by the same examiner in each of 20 healthy volunteers within 10 days, with a minimal interval of 2 days between two subsequent examinations. The observer was blinded to previous results. The reproducibility was evaluated by calculating the correlation coefficient (r) and the coefficient of variance (CV) of the difference between the values obtained from the second and the third examination vs. the first examination. The results showed good reproducibility of TCCD velocity measurements in all examined arteries: for maximal systolic velocity r was 0.80-0.94 (p < 0.001), and CV was 5.5-9.4%; for maximal end-diastolic velocities r was 0.89-0.94 (p < 0.001), and CV was 6.6-12.2%.