Assessment Of RCBF And Cerebrovascular Reserve By Xenon CT In Ischemic Stroke Patients

Background:Xenon CT is an imaging technology which can messure rCBF absolute value exactly.It can be used to assess the rCBF and cerebrovascular reserve(CVR)in the patients suffered from ischemic stroke.CVR is a powerful and independent predictor of stroke,espatially in the patients with cerebrovascular stenosis.But few research use Xenon CT combined acetazolamide challenge to messure CVR. Otherwise,the effect of stent to improve CVR in the patients with cerebrovascular stenosis still remains to be confirmed by research.Object:To measure the cerebrovascular reserve(CVR)in patient suffered from ischemic stroke by Xenon CT combined acetazolamide challenge.To discuss weather stent placement can increase CVR and benefit the patients with cerebrovascular stenosis.Method:32 objects participated in this study.22 of them were selected from the inpatients with cerebrovascular stenosis who had suffered from ischemic stroke in the past one year.The other ten were normal volunteers.All the objects were examined by Xenon CT to measure the resting rCBF.Acetazolamide(ACZ)challenges were quantitatively measured to evaluate cerebrovascular reserve(CVR)of 20 patients in the case group.Two patients received stent placement were examined pre/postoperation to assess the change of CVR.Result:1.No significant difference between case and control groups in resting rCBF of whole brain.The difference of two cerebral hemispheres in case group was more significant than in control group,(p＜0.01).In criminal MCA region of case group,the resting rCBF is lower than the control,significant in left criminal MCA region (p＜0.05).2.rCBF increased after ACZ challenge in cases,(p＜0.05).The mean of CVR was 24.89±25.3%.3.No difference between lesional cerebral hemisphere and normal cerebral hemisphere in CVR and resting rCBF.After ACZ challenge,the rCBF of lesional side is lower than the normal side,(p＜0.05).4.We compared the rCBF in the whole region supplied with stenosis artery(divided manully)with that in the corr-region of normal side.No significant difference in resting rCBF but in CVR (lesion side vs.normal side=5.9±24.3%vs.25.9±32.6%,p＜0.05).Then we compared the contex rCBF of both regions(divided by computer)and got the oppsite result.No significant difference in CVR but in resting rCBF(lesion side vs.normal side=45.7±13.3 vs.55.1±14.5 ml/min^-1.100g^-1,p＜0.05).5.The CVR of lesion area improved after stent placement in both two patients.Conclusion:The application of Xenon CT is useful to measure rCBF and CVR. Impaired CVR is an important character of the patients with cerebrovascular stenosis suffered from stroke.Measuring CVR can be used to assess the effect of stent placement.