急性缺血性卒中患者溶栓治疗前后CT微血管表面通透性参数图的特点分析

Analysis of Microvascular Permeability Surface in Acute Ischemic Stroke Before and After Thrombolytic Therapy Using CT Perfusion Imaging

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摘要目的分析动态计算机X线断层扫描灌注(CTperfusion,CTP)成像获得的脑组织局部微血管表面通透性(permeability surface,PS)参数图在急性缺血性卒中中的分布特点以及其在溶栓治疗前后的变化。方法急性缺血性卒中发病3～8h内的入组患者分别在基线和静脉溶栓治疗后接受"一站式"CT检查。使用Patlak模型分析CTP图像并得到PS参数图,分别测量基线和溶栓后的患侧和健侧脑组织的微血管PS值,分别记为:患侧基线PS(PSischemia-pre)、健侧基线PS(PScontrol-pre)、患侧溶栓后PS(PSischemia-post)和健侧溶栓后PS(PScontrol-post)。结果22例患者基线时接受"一站式"CT检查以及静脉溶栓治疗,17例患者完成(24±6)h随访的CTP成像评价。患者的基线PS值患侧较对侧升高[6.20ml·min-1·(100ml)-1vs0.65ml·min-1·(100ml)-1,P<0.01];溶栓治疗后PS值患侧仍较健侧为高[3.39ml·min-1·(100ml)-1vs0.39ml·min-1·(100ml)-1,P<0.01]。基线以及溶栓后患侧和健侧PS定量值均具有统计学差异(P<0.01)。17例基线和随访CTP均可评估的数据中,13例(76%)患者溶栓治疗后PS值降低,但患侧基线和溶栓治疗后PS值差异无统计学意义(P=0.093)。22例患者中1例发生出血转化,其PSischemia-pre为6.74ml·min-1·(100ml)-1。结论动态CTP成像获得的PS参数图可以用来反映急性缺血性脑组织缺血区域的通透性异常增高。 Objective To determine the microvascular permeability surface（PS） area product in acute ischemic stroke using dynamic computed tomography perfusion（CTP） and to analyze the characteristics before and after thrombolytic therapy. Methods According to inclusion criteria, the selected patients underwent a baseline ＂One Stop Shop＂ computed tomography（CT） examination within 3-8 hours of onset of symptoms and a follow-up study after they accepted rt-PA treatment. The Patlak model was applied to generate PS color maps from CTP. One radiologist analyzed each PS map by drawing 4 circular regions of interest（ROI） on hypoperfusion area that was in charge of the onset, and mirror regions of interest were automatically placed on the contralateral nonischemic hemisphere. According to the median of the 4 ROI, baseline PS（PSischemia-pre and PScontrol-pre） and follow-up PS（PSischemia-post and PScontrol-post） were obtained, respective. PSischemia-pre and PScontrol-pre, PSischemia-post and PScontrol-post, PSischemia-pre and PSischemia-post were compared by using an exact Wilcoxon test. Results Twenty-two patients were evaluated by baseline CTP and seventeen patients completed the follow-up CTP evaluation. Seventeen patients（77%） showed focal PS elevation in the region of infact. PSischemia-pre ranged from 1.28 to 29.36ml·min^-1（100ml）^-1（median： 6.20） versus PScontrol-pre of 0 to 4.29（0.65; P〈0.01）, PSischemla-post of 0.54 to 12.15（3.39） versus PScontrot-post of 0 to 4.44（0.39; P〈0.01）. And the difference between PSischemia-pre and PSischemia-post was no significant（Z=-1.681, P=0.093）. One of these twenty-two patients developed hemorrhagic transformation（HT） on follow-up imaging and the PSischemia-pre was 6.74ml·min^-1·（100ml）^-1. Conclusion Elevated permeability can be detectable in acute ischemic stroke by using dynamic CTP.