TRANSCRANIAL DUPLEX SONOGRAPHY OF MIDDLE CEREBRAL-ARTERY STENOSIS - ACOMPARISON OF COLOR-CODING TECHNIQUES - FREQUENCY-BASED OR POWER-BASED DOPPLER AND CONTRAST ENHANCEMENT

The main limitation of transcranial colour-coded duplex sonography (TC CD) is the inadequate acoustic window, which prevents transtemporal id entification of the basal cerebral arteries in up to 30% of cases, esp ecially in the elderly. TCCD with different colour-coding techniques, including frequency-based colour-flow (CFD) or power (PD) Doppler sono graphy, used alone or in combination with contrast media, were used in 23 patients with middle cerebral artery (MCA) stenosis. In 10 patient s a contrast medium (400 mg/ml SHU 508 A) was administered because of inadequate colour-coded visualisation with TCCD. The data were compare d with angiographic methods. Digital subtraction angiography (DSA) rev ealed 2 low-grade, 11 middle-grade and 10 high-grade stenoses in the M 1 segment. With TCCD, we found a 7.7% higher blood Row velocity (systo lic peak velocity) than with transcranial duplex sonography without co lour-coding because of visual angle correction and a 20% higher systol ic peak velocity using contrast enhancement. CFD did not differ from P D in identification of low- and middle-grade MCA stenoses, but PD alon e revealed two more cases of high-grade stenosis than CFD. The contras t medium increased diagnostic confidence in 8 of 10 cases. Only 2 of 2 3 MCA stenoses (9%) could not be shown using TCCD.