The inferior petrosal sinus: Assessment by transcranial Doppler ultrasoundusing the suboccipital approach

Recently, intracranial veins and sinuses have been successfully insonated u sing the transtemporal and transoccipital approaches by transcranial Dopple r ultrasound. The purpose of this study was to prove the capacity of the Do ppler method to evaluate the inferior petrosal sinus via the suboccipital a pproach. Venous transcranial ultrasound was performed with a range-gated 2- MHz transducer in 80 healthy volunteers and patients without central nervou s system disorders ranging in age from 15-84 years (mean +/- standard devia tion [SD], 37.6 +/- 15.2 years). A venous signal with a flow directed towar d the probe was considered to originate from the inferior petrosal sinus be cause of its proximity to the basilar artery. The inferior petrosal sinus w as insonated in 96.3% of the cases at least on one side. It was found bilat erally in 48 (60%), on the right side in 74 (92.5%), and on the left side i n 51 (63.8%) subjects, respectively. Mean blood flow velocity ranged from 8 -53 cm/s (mean +/- SD, 19.6 +/- 8.7 cm/s). A significant age dependency of venous velocities was found. Weak but significant side-to-side differences were observed, reflecting the known right-sided predominance of venous outf low in humans. Using the suboccipital approach, the inferior petrosal sinus can be insonated in a high percentage of subjects without major difficulti es and is defined by its vicinity to the basilar artery.