[Transcranial Doppler ultrasonography and hyperventilation test in assessment of cerebral vasoreactivity after...

In 36 patients 3 month after ischaemic stroke in regions supplied by MCA (Middle Cerebral Artery) physical examination, CT scanning and blood flow velocity recordings in ICA (Internal Carotid Artery) and MCA were performed. In both MCA blood flow velocity was measured in resting state and after 30 sec. of hyperventillation. The control group consisted of 40 healthy volunteers. In the control group blood flow decrease after hyperventillation was nearly equal in both hemispheres (38% in right and 37% in the left hemisphere). In studied group in the symptomatic hemisphere blood flow reduction was 21%. Vasoreactivity in the opposite hemisphere was similar to that in control group (35% decrease). The results suggest that vasoreactivity diminution is a local phenomenon limited to the infarcted area. Hyperventilation test, despite its simplicity, seems to be sufficient for screening vasoreativity.