基于表观扩散系数阈值的超急性期表观扩散系数图预测亚急性期脑梗死体积的可行性  

Prediction of subacute infarct lesion volumes by processing apparent diffusion coefficient maps based on apparent diffusion coefficient cut-off values in patients with acute stroke

作　　者：郭翔[1] 周洁洁 陈伟建[1] 杨运俊[1] 高凌云[1] 薛静[2] 高培毅[2] 张辉[1] 戴一川 

机构地区：[1]温州医科大学附属第一医院放射科,325000 [2]首都医科大学附属北京天坛医院放射科

出　　处：《中华放射学杂志》2014年第6期448-451,共4页Chinese Journal of Radiology

基　　金：“十二五”国家科技支撑计划项目（201lBAl08809）;浙江省科技计划项目（2012C37029）;浙江省卫生厅科技计划项目（2011KYB050）

摘　　要：目的探讨基于ADC阈值的超急性期ADC图预测亚急性期（发病后4—7d）脑梗死体积的可行性。方法应用DWI及常规MRI对20例超急性期脑梗死患者进行基线（发病至首次MR检查的时间〈6h）和亚急性期复查扫描。将基线DWI与复查FLAIR均显示异常高信号的脑组织认为是缺血中心，基线DWI与复查FLAIR不一致的异常高信号脑组织认为是影像半暗带。在基线DWI图像上，分别测定缺血中心、影像半暗带及其相应对侧正常脑组织的ADC值，并计算相对ADC（rADC）值。将影像半暗带的rADC值设定为ADC阈值，小于该阈值的区域视为预测梗死区。采用GE公司专用后处理软件，以DWI图像作为输入数据、代入ADC阈值得到ADC图。分别测量DWI、ADC图与复查FLAIR异常信号区域的体积。采用成组t检验比较缺血中心、影像半暗带rADC值；采用Kruskal—Wallis H检验评估各体积值之间的差异；Spearman秩相关分析研究基线DWI、ADC图体积与复查FLAIR异常信号体积的相关性。结果缺血中心与影像半暗带的ADC值较对侧正常脑组织明显下降，缺血中心的rADC值（0．620±0．116）显著低于影像半暗带的rADC值（0．809±0．097），差异有统计学意义（t=8．083，P〈0．01）。复查FLAIR梗死体积[16．3（4．7，29．0）cm^3]与ADC图异常区域体积[13．5（4．8，25．4）cm^3]、DWI异常区域体积[11．0（4．4，30．4）cm^3]均呈显著线性相关（r值分别为0．967、0．950，95％可信区间分别为0．872—0．995、0．826～0．983，P值均〈0．01）。DWI、ADC图与复查FLAIR异常信号的体积相比，经Kruskal—Wallis H检验，差异无统计学意义（H=0．168，P〉0．05）。结论基于ADC阈值的超急性期ADC图异常区域体积与亚急性期梗死体积有着很好的一致性，为预测梗死变化提供了新的方法。Objective To explore the feasibility of prediction of subacute infarct lesion volumes by processing ADC maps based on ADC cut-off values in patients with acute stroke. Methods MRI was performed in 20 patients with clinically diagnosed acute infarct less than 6 h after stroke onset. The MRI included a DWI and conventional MRI. The follow-up MR examinations of all the patients were carried out within 4--7 days after admission. The brain tissue, which showed abnormal high intensity both in DWI at the baseline and FLAIR at the reexamination, was regarded as the area of the initial ischemia core. Graphic- penumbra was regarded as the difference between initial DWI and follow-up FLAIR. The ADC values of the ischemia core, graphic-penumbra and the contralateral normal brain tissue, the relative ADC （rADC） were measured. The rADC value of the graphic-penumbra was defined as the ADC cut-off values. GE medical system based on ADC cut-off values was also tested in these patients to obtain ADC maps. The lesion volumes, the abnormal area seen on the DWI, ADC maps and follow-up FLAIR, were also measured, rADC values in different areas were analyzed by paired Student t test. Relationship between baseline DWI, ADC map and follow-up FLAIR was analyzed using Spearman rank-order correlation test, and Kruskal-Wallis H test was used to compare the volumes among three groups. Results Absolute ADC and rADC values gradually increased from the core to the periphery of the ischemic lesion. The absolute ADC values statistically differed from those on the contralateral side for both ischemia core and graphic-penumbra. The rADC values were significantly decreased in the ischemia core （0. 620 ± 0. 116） compared with the graphic-penumbra values （0. 809 ± 0. 097 ; t = 8.083, P 〈 0.01 ）. The lesion volume of follow-up FLAIR [ 16. 3 （4. 7, 29. 0）cm3] correlated highly with both volume predicted with the ADC map [ 13.5 （4. 8, 25.4） cm3] （r=0.967, P〈0. 01） and baseline DWI volume [11.0 （4.4,30.4） cm3] （r=0.950, P

关 键 词：卒中 磁共振成像 弥散 

分 类 号：R743.3[医药卫生—神经病学与精神病学]