肝细胞急性坏死与凋亡的磁共振扩散加权成像活体检测实验研究

目的评价MRI、DWI检测及鉴别肝细胞凋亡和坏死两种病理改变的价值。方法72只S—D大鼠随机分成假手术对照组、右侧肝动脉与门静脉分支均结扎组（HA＋PV组）和单独右侧门静脉分支结扎组（PV组），各24只。每组再分成4个亚组，每个亚组6只，分别于术后3h、12h、24h、72h行MRI、DWI检查，检查结束后取肝标本作HE染色、TUNEL染色，将病理结果与影像检查进行对照分析。结果右侧门静脉与肝动脉均结扎后，肝右叶于术后3h在T2WI上即表现为高信号，ADC值下降。单独肝右侧门静脉结扎后12h，肝右叶ADC值出现升高，至24h肝细胞凋亡数达最高，ADC值也达最高。结论T2WI和DWI可早期检测发生坏死的肝组织。而组织中细胞发生凋亡后，DWI较T1WI、T2WI早期检测到凋亡组织。

Experimental study on acute hepatocyte necrosis and apoptosis with diffusion-weighted imaging

Objective To appraise the value of MR imaging(MRI) and diffusion-weighted imaging(DWI) in detecting and characterizing hepatocyte necrosis and apoptosis in vivo,compared with pathological changes.Methods Seventy-two S-D rats were randomly divided into three groups: a shamoperated control group,a necrosis group with both right hepatic artery and right portal vein ligated(HA+PV group),and an apoptosis group with only right portal vein ligated(PV group).There were 4 sub-groups(6 rats each) in the HA+PV group or PV group.The rats in each group were examined by MRI and DWI at 3 h,12 h,24 h,and 72 h after the ligation.After examination,the animals were sacrificed and sampled immediately for HE and TUNEL staining.We compared the results of pathological examination and those of MRI and DWI.Results In HA+PV group,there were an increase in signal intensity on T_2WI and a decrease in ADC value on right hepatic lobes at 3 h after operation.At 12 h after ligation of right portal vein alone,the ADC value of right lobes increased;when apoptotic cells reached maximum at 24 h,right hepatic lobes had hyper-intensity on T_1WI,hypo-intensity on T_2WI,and ADC value reached maximum.Conclutions T_2WI and DWI can detect necrosis of liver tissue early.But for apoptotic tissue,DWI can detect apoptosis at a very early stage,much earlier than T_1WI and T_2WI.