Venous Doppler ultrasound assessment of the parasellar region

The purpose of this report is to present normal values for venous blood flow velocities from the parasellar region using transcranial Doppler ultrasound (2-MHz transducer) with both transtemporal and transorbital approaches and to examine the nature of previously reported low-pulsatility signals with velocities in the arterial range from this area. Forty-three subjects ranging in age from 18 to 56 years (mean +/- SD, 31.9 +/- 10.1 years) were examined. In all subjects, a venous signal directed away from the probe with the source lateral to the internal carotid artery siphon was detected on at least one side. A total of 72 parasellar venous signals were insonated. Signals were considered to belong to the main inflow and outflow vessels of the cavernous sinus. The mean blood flow velocity ranged from 6 to 81 cm/s (mean +/- SD, 27.3 +/- 17.4 cm/s). Typical transients in the Valsalva test confirmed the venous character of the signals. No significant gender, side-to-side or age dependency was observed. A separate analysis was done for venous high-velocity signals defined by a mean blood flow velocity greater than 30 cm/s. They were detected in 21 out of 43 subjects (48.9%) via a transtemporal approach and in 6 of them (14%) via the transorbital route, too. Again, no significant gender, side-to-side or age dependency was noted. In summary, we found a greater variability of venous blood flow velocities in the parasellar region compared to other basal cerebral veins, e.g. the basal vein of Rosenthal. The previously reported low-pulsatility signals with velocities in the arterial range proved to be of venous origin.