Morphometry of intraluminal side-to-side differences in human basal cerebral arteries.

Intraindividual variability of Doppler frequencies in the basal cerebral arteries is higher than the variability in perfusion measurements. Since Doppler frequency is dependent on vessel diameter, we measured intraluminal vessel diameters post mortem. In 73 human cadavers, we measured fresh pairs of rings of the terminal internal carotid artery, the anterior and the middle cerebral artery. Mean intraluminal diameters (+/- standard deviation) for the respective vessel segments were 2.8 +/- 0.49 mm (2.72 +/- 0.49 mm), 1.61 +/- 0.37 mm (1.63 +/- 0.39 mm) and 2.10 +/- 0.38 mm (2.10 +/- 0.41 mm). The left/right ratio was 1.04 +/- 0.13, 1.05 +/- 0.35 and 1.02 +/- 0.17. Intraindividual asymmetries in intraluminal vessel diameters might be an additional factor in the interpretation of intracranial Doppler frequency measurements.