The effect of contrast material on transcranial Doppler evaluation of normal middle cerebral artery peak systolic velocity.

BACKGROUND AND PURPOSE Several recent studies have shown that sonographic contrast agents may affect transcranial Doppler evaluation of the arterial peak systolic velocity (PSV). Some investigators reported an increase in PSV, and others reported no change in PSV compared with baseline values. This study was conducted to determine the effect of sonographic contrast agent on PSV measured in normal middle cerebral arteries. METHODS Continuous spectral Doppler sonography was performed on the right middle cerebral artery of 20 participants with angiographically proven normal intracranial vasculature. Videotaping was performed in each case from the initiation of the administration of contrast medium until the effect of the contrast agent on the PSV subsided. The PSV values were normalized for each participant, were pooled, and were plotted as a function of time. RESULTS PSV increased in all participants after the administration of contrast material; the mean maximum increase was 24+/-7.4% (mean +/- standard deviation) (range, 15-36%). The mean duration of PSV increase was 320+/-97 s (range, 165-465 s). CONCLUSION The middle cerebral artery PSV increased substantially after the administration of contrast material. This effect needs to be considered if velocity thresholds developed for disease detection without the use of contrast materials are used when contrast agents are administered.