不同时间窗急性缺血性卒中在FLAIR、DWI序列上的信号变化

Time course of signal changes in FLAIR and DWI sequences in acute ischemic stroke

目的:探讨急性缺血性卒中在FLAIR、DWI序列上病灶信号强度随时间变化的过程。方法:收集发病时间≤48h的急性缺血性卒中240例,根据发病时间,分为6组,≤4.5h组(19例)、>4.5~6h组(24例)、>6~12h组(55例),>12~24h组(43例),>24~36h组(53例),>36~48h组(46例)。分别测量FLAIR、DWI序列病变侧、健侧信号强度值及ADC值,计算病变侧/健侧信号强度比值(RSI)及相对ADC值,并进行统计学分析。结果:①FLAIR序列各组RSI值间差异具有统计学意义(P<0.05)。48h内,随着卒中时间的延长,FLAIR序列的RSI呈上升趋势。②DWI序列各组RSI值差异无统计学意义(P>0.05),各组相对ADC值差异无统计学意义(P>0.05)。在48h内,DWI的信号强度及相对ADC值未出现上升或下降趋势。结论:急性缺血性卒中FLAIR序列的病灶信号强度随发病时间的延长而增加;DWI的RSI及相对ADC值随时间变化未出现上升或下降趋势。

Objective:To study the time-dependent changes of signal intensity (SI) on FLAIR and DWI sequences in acute ischemic stroke. Methods:A total of 240 patients with acute ischemic stroke whose onset time was within 48 h were collected. According to the onset time,240 patients were divided into 6 groups:group of shorter than 4.5 h (19 cases),group of 4.5~6 h (24 cases),group of 6~12 h (55 cases),group of 12~24 h (43 cases),group of 24~36 h (53 cases) and group of 36~48 h (46 cases). SI and ADC value of affected side and unaffected side in FLAIR and DWI were measured,and the relative signal intensity (RSI) of the lesion side to the sound side was calculated and analyzed statistically. Results:①On FLAIR sequence,the difference of RSI value of 6 groups was statistically significant (P<0.05). With the prolongation of stroke time,the RSI value showed an upward trend.②On DWI sequence,there were no significant differences in RSI value and relative ADC value of 6 groups (both P>0.05). There was no increase or decrease in SI and relative ADC values within 48 h on DWI sequence. Conclusions:In acute ischemic stroke,the SI on FLAIR sequence increases with the onset time,but on DWI,RSI and relative ADC values does not increase or decrease with time.