灌注加权成像-弥散加权成像不匹配与缺血性卒中静脉溶栓后早期再灌注的相关性

Correlation between perfusion weighted imaging.diffusion weighted imaging mismatch and early reperfusion after intravenous thrombolysis in acute ischemic stroke

目的探讨溶栓治疗前的灌注加权成像（PWI）-弥散加权成像（DWI）不匹配模式对溶栓后组织的再灌注以及溶栓后早期神经功能恢复的影响。方法回顾分析连续收集的具有溶栓前和溶栓后24h多模式MRI的缺血性卒中溶栓患者的临床和影像资料，将PWI—DWI目标不匹配定义为同时满足：@PWI／DWI≥1．2；②PWI和DWI体积差≥10ml；③DWI体积〈70ml；④PWI体积〈140ml。DWI和PWI都〈10ml为小梗死灶；其余为非目标不匹配。将再灌注定义为溶栓后24h内PWI体积较溶栓前下降I〉30％，早期神经功能改善定义为发病后1周NIHSS评分为0—4分或1周时NIHSS评分较基线改善≥6分。结果共有45例患者纳入分析，19例（41％）患者存在目标不匹配，其中有8例溶栓时间超过4．5h。溶栓后24h，目标不匹配组的再灌注率较非目标不匹配组显著增加（16／19和5／12，X^2=6．092，P〈0．05），神经功能改善的比例也显著提高（13／19和2／12，）（2=7．888，P〈0．05），但两组的血管再通率差异无统计学意义。目标不匹配组获得再灌注的OR=6．4，95％CI1．156～35．437，P=0．034，获得早期神经功能改善的OR=21．7，95％CI2．234—210．110，P=0．008。16例获再灌注的目标不匹配患者中13例早期神经功能改善，而未再灌注的目标不匹配患者中无一例获神经功能改善。目标不匹配患者中，4．5h内溶栓和4．5h后溶栓者血管再通、再灌注以及神经功能改善差异均无统计学意义。结论溶栓前存在PWI-DWI不匹配模式的患者较无不匹配者溶栓后再灌注率高，而且早期神经功能改善比例高，可能有利于筛选时间窗外溶栓受益患者。

Objective To investigate the impact of the pretreatment perfusion weighted imaging （PWI）-diffusion weighted imaging （DWI） mismatch on reperfusion and early neurological improvement after intravenous thrombolysis in acute ischemic stroke. Methods We retrospectively reviewed our collected clinical, laboratory, and radiologic data in patients receiving intravenous recombinant tissue plasminogen activator therapy, who had performed multimodal MRI in both pretreatment and 24 h post-treatment in our hospital. The ＂target mismatch＂ of PWI-DWI was defined as a PWI lesion that was 10 ml or more and 120% or more of the DWI lesion, with DWI lesion less than 70 ml and PWI lesion less than 140 ml. The ＂small lesion＂ was defined as a DWI and PWI volume both less than 10 ml. The others were termed ＂non-target mismatch＂. Reperfusion required a 30% or greater reduction in PWI lesion volume on the 24-hour follow-up scan. The ＂early neurological improvement＂ was defined as the patients with an NIHSS score of 0 to 4 or 6-point or greater improvement at 7 days. Results Among 45 patients analyzed, 19 （41%） patients presented ＂target mismatch＂, of which 8 patients were treated over 4. 5 h. The rate of reperfusion and early neurological improvement after thrombolysis in target mismatch group were both significantly increased comparing with non-target mismatch group（ 16/19 vs 5/12, X^2 =6. 092,P 〈0. 05 and 13/19 vs 2/12, X^2 =7. 888, P 〈 0. 05, respectively ）, although the recanalization rate demonstrated no significant difference between two groups. The pooled OR for reperfusion was 6. 4（95% CI 1. 156-35. 437, P =0. 034）, and the pooled OR for favorable clinical response was 21.7 （95% CI 2. 234-210. 110, P = 0. 008）in target mismatch patients. Among the target mismatch group, 13/16 of patients with reperfusion had early neurological improvement, while no patients without reperfusion had neurological improvement. The rate of recanalization, reperfusion and neurological improvement after thrombolysis demonstrated no significant difference between target mismatch group treated within 4. 5 h and beyond 4. 5 h. Conclusion Patients with target mismatch profile before thrombolysis had a high reperfusion rate and were prone to get early neurological improvement, indicating that the evaluation of PWI-DWI mismatch may facilitate the selection of patients who may benefit from thrombolysis beyond the time window.