Responsibility of cerebral artery in cerebral thrombosis of internal carotid artery to CO2 using 133Xe-inhalation technique

Using 133Xe-inhalation technique quantitative measurements the regional cerebral blood flow (rCBF) was performed in 20 patients with unilateral ischemic lesion in one hemisphere according to cranial CT scan and in 10 normal subjects. Twenty patients had an Ultrasound Doppler examination of neck vessels half a day after rCBF examination. The results showed that rCBF in ischemic hemisphere before and during 3% CO2 stimulation was lower than that in normal subjects or in non-ischemic hemisphere of the patients. It suggests that dilative responsibility to CO2 in cerebral artery of stroke hemisphere is reduced. That is to say the cerebrovascular reserve capacity in stroke hemisphere was reduced too, but cerebrovascular reserve capacity in the non-stroke hemisphere and in normal subject of control group was normal. It is also found that cerebrovascular responsibility to CO2 or cerebrovascular reserve capacity correlated with severity of clinical cerebral thrombotic illness and extent and degree of internal carotid artery obstruction. It was poor in severe illness or internal carotid obstruction and/or narrow in both sides of the patient group taken by Ultrasound Doppler examination of neck vessels