颈动脉狭窄患者术前CT灌注成像特点及临床意义研究

目的　探讨颈动脉狭窄患者术前脑血流CT灌注成像（CTP）特点及其预测颈动脉狭窄术后发生脑过度灌注综合征（CHS）/脑过度灌注（CH）危险性的应用价值。方法　回顾性选择首都医科大学附属北京天坛医院2015年1—12月诊治的64例颈动脉狭窄患者，患者均行单侧颈动脉支架血管成形术（CAS）/颈动脉内膜剥脱术（CEA），术前行CTP检查判断责任血管（术侧血管）；并根据责任血管对侧颈动脉血管狭窄程度分为5组：A组为颈动脉闭塞（狭窄率100%）10例；B组为颈动脉重度狭窄（狭窄率75%~99%）17例；C组为颈动脉中度狭窄（狭窄率50%~74%）7例；D组为颈动脉轻度狭窄（狭窄率<50%）4例；E组为颈动脉血管正常26例。采集术前血流动力学指标，即局部脑血容量（rCBV）指数、局部脑血流量（rCBF）指数、局部平均血流通过时间（rMTT）指数和局部对比剂达峰时间（rTTP）指数，并进行比较。结果　33例发生CH（主要表现为血压升高，轻度头痛、头晕），1例发生CHS（主要表现为血压升高，明显头痛、恶心、颅内出血）；30例未发生CHS/CH；术后血压升高发生率为51.6%（33例）。A、B组发生CHS/CH患者的rCBV、rTTP指数高于C、D、E组发生CHS/CH患者（P<0.05）；各组发生CHS/CH患者rCBF、rMTT指数比较，差异无统计学意义（P>0.05）。结论　颈动脉（责任血管）中、重度狭窄伴对侧颈动脉闭塞或严重狭窄的患者，若术前rCBV指数及rTTP指数增加，特别是rCBV>0.20、rTTP>0.25，提示术后发生CHS及CH趋势。术前rCBV、rTTP指数为预测单侧颈动脉狭窄患者CAS/CEA术后发生CHS及CH提供了一种有效的评估方法。

Characteristics and Clinical Significance of Preoperative CT Perfusion Imaging in Patients with Carotid Stenosis

Objective　To discuss the preoperative value of CT perfusion imaging （CTP） on patients with carotid artery stenosis in forecasting the risk of postoperative cerebral hyperperfusion syndrome（CHS） and Cerebral hyperperfusion（CH）．Methods　The retrospective study was performed on 64 patients admitted to Beijing Tiantan Hospital，Capital Medical University from January to December 2015.Subjects had undergone unilateral carotid artery stenting（CAS） / carotid endarterectomy （CEA），and preoperative CT perfusion imaging was performed to determine the blocked carotid artery.These patients were divided into 5 groups by carotid stenosis; Group A: carotid occlusion group （stenosis 100%） of 10 cases; Group B: severe carotid stenosis group （stenosis 75%-99%） of 17 cases; Group C: moderate carotid stenosis group （stenosis 50%-74%） of 7 cases; Group D: mild carotid stenosis group （stenosis< 50%） of 4 cases; Group E: normal carotid artery group of 26 cases.Preoperative CT perfusion parameters were collected and compared，including local cerebral blood volume（rCBV）index，local cerebral blood flow（rCBF）index，local mean transit time （rMTT）index and local time to peak （rTTP）index.Results　Cerebral hyperperfusion occurred in 33 cases （high blood pressure，mild headache，dizziness），and cerebral hyperperfusion syndrome occurred in 1 case，with symptoms of elevated blood pressure，obvious headache，nausea，and intracranial hemorrhage.Thirty cases showed no excessive perfusion.The incidence of high blood pressure after the operation was 51.6% （33 cases）.The levels of rCBV index and rTTP index in Group A and B were significantly higher than those in Group C，D and E（P<0.05）.The rCBF index and rMTT index levels among different groups were not statistically significant（P>0.05）.Conclusion For patients with mild and severe stenosis in internal carotid artery （blocked blood vessel） with contralateral carotid artery occlusion or severe stenosis，if the preoperative rCBV index and rTTP index significantly increased，especially when rCBV index >0.20 and rTTP index >0.25，CHS and CH are more likely to occur after the operation; therefore，the preoperative rCBV index and rTTP index provide a potential value in predicting CHS after the CAS/CEA surgery on patients with unilateral internal carotid artery stenosis.