急性缺血性脑卒中溶栓治疗前后多层螺旋CT灌注成像研究

目的评价多层螺旋CT灌注成像（CT perfusion imaging，CTPI）预测不可逆性脑缺血损伤的价值及溶栓治疗后CTPI各参数变化过程。方法采用16层螺旋CT对31例急性缺血性脑卒中患者（发病时间≤24h）行CTPI检查，并复查平扫CT及CTPI，分析梗死区和半暗带的相对脑血流量（relative cerebral blood flow。rCBF）、相对脑血容量（relative cerebral volume，rCBV）、相对平均通过时间（relative mean transmit time，rMTT）、相对达峰时间（relative time to peak，rTTP）的数值变化。结果中心梗死区各参数的阈值为rCBF〈15．1％、rCBV〈25．7％、rMTT〉253．3％、rTTP〉106．3％。半暗带各参数的阈值为rCBF〉34．7％、rCBV〉62．7％、rMTT〈230．6％、rTTP〈115．0％。rCBF与rCBV联合应用可以提高预测不可逆性脑损伤的灵敏度、特异度。溶栓治疗后梗死区rCBF、rCBV均逐渐升高。结论CTPI可预测脑缺血组织的预后。rCBF与rCBV联合应用有利于梗死区和半暗带的判定。溶栓治疗后由于造影剂外渗及血管再生导致梗死区rCBF、rCBV均逐渐升高。

Investigation of multi-slice CT perfusion imaging in acute ischemic stroke before and after thrombolytic therapy

Objective To study the capability of multi-slice CT perfusion imaging(CTPI)in the prediction of irreversible ischemic brain damage,and to investigate the changes in CTPI after thrombolytic therapy.MethodsCTPI scans were obtained within 24 hours after the onset in 31 patients with acute ischemic stroke,the results were analyzed by referring to the follow-up CT scans and CTPI scans.ResultsThe threshold values were <15.1%,<25.7%,>253.3%,and 106.3% for rCBF,rCBV,rMTT and rTTP(relative cerebral blood flow,relative cerebral volume,relative mean transmit time and relative time to peak),respectively,in the infarction region;and were >34.7%,>62.7% and <230.6% for rCBF,rCBV and rMTT,respectively,in the penumbra.The prediction of irreversible brain tissue damage could be improved in sensitivity and specificity by using a combination of the perfusion parameters.After thrombolytic therapy,the rCBF and rCBV were both increased gradually in the infarct region.ConclusionCTPI can be used to predict the outcome of ischemic brain tissue.A combined use of rCBF and rCBV helps demarcate the infarct region and the penumbra.The delayed increase in rCBF and rCBV may be associated with the angiogenesis and a possible leakage of contrast media.