Transcranial colour coded sonography as an aid to measurement of blood flow velocity in the basal cerebral arteries.

Unlike conventional transcranial Doppler, transcranial colour coded sonography allows imaging of the basal cerebral arteries. We used this technique to determine blood flow velocities, with compensation for the angle of insonation, in the anterior and posterior cerebral circulation of 60 volunteers categorised by age (20-39, 40-59, > 60 years). Successful vessel insonation declined with increasing age: 40/40 middle cerebral arteries insonated 20-39 y, 31/40 insonated > 60 y. Peak, mean and end diastolic blood flow velocities also decreased with age in all arteries: 20-39 y middle cerebral artery mean velocity = 72 cm/s; > 60 y middle cerebral artery mean blood flow velocity = 58 cm/s; p < 0.0001. The pulsatility index increased significantly with age in the middle, posterior cerebral (P2 segment) and vertebral arteries (p < 0.05-0.005), however the resistance index increased significantly with age in all vessels (p < 0.05-0.0001).