大鼠右肝血供不同程度阻断后的病理变化及磁共振表现

目的:探讨用磁共振新技术活体检测肝细胞凋亡和坏死的可能性。方法:①体重为0.25～0.3kg的SD大鼠90只随机分成A、B、C三组,每组30只,分别行右肝门静脉结扎(A组)、右肝门静脉及肝动脉双结扎(B组)及假手术(C组),术后3h、1天、3天、7天、14天作为5个时间点,各观察6只。②每组大鼠进行磁共振成像(MRI)、磁共振扩散加权成像(DWI)、1H磁共振波谱(1H-MRS)及磁共振灌注成像(PWI)检查。③取肝脏标本行病理学及电镜检查。④将磁共振检查结果同病理学及电镜对照分析。结果:①A组病理学及电镜检查证实肝细胞发生凋亡;B组肝组织发生凝固性坏死。②A组T1WI信号增高,T2WI信号刚开始略减低,后呈小片状增高;DWI呈小片状高信号,表观扩散系数(ADC)图则相反;MRS表现为胆碱(Choline,Cho)、肌酸(Creatine,Cr)、谷氨酸(Glutamate,Glx)峰稍下降,乳酸(Lactate,Lac)峰、脂质(Lipid,Lip)峰增加;PWI灌注曲线下降;③B组T1WI信号减低,T2WI信号增高;DWI呈高信号;Cho峰下降明显,Cr、Glx峰下降,Lac峰明显升高,Lip峰略增高;PWI曲线低平。结论:右肝血供不同程度阻断后肝细胞分别发生凋亡和坏死;磁共振检查(DWI、MRS、PWI)具有特征性表现,可活体检测细胞凋亡和坏死的存在。

Changes of Pathology and MRI in Rat Right Hepatic Lobe by Obstruction of Blood Supply

Objective:To discuss the probability of detecting apoptosis and necrosis of hepatic cells in vivo by MRI new technique.Methods:90 rats with body weight 250~300g were randomly divided into three groups,with 30 rats in each group.Group A had ligation of the right portal vein for detecting apoptosis.Group B had ligation of both the right hepatic artety and portal vein for the aim of detecting necrosis.Group C had no obstruction of blood supply,just for control and comparison.Six rats from each group were observed at 3h,1d,3d,7d,14d after operation.All rats of each group were examined by MRI,DWI,MRS and PWI.The right hepatic lobes were sampled and examined for pathology and electronic microscopy.MRI and the results of pathology were analyzed by comparison.Results:For group A,cell apoptosis in rat hepatic right lobe was proved by pathology and electronic microscopy.For group B,coagulative necrosis was found in right hepatic lobe.There were some changes between group A and group B,including the intensity of T_1 higher,the intensity of T_2 lower at first and higher at other time,the intensity of DWI higher,the intensity of ADC lower,the peak of Cho,Cr and Glx a little lower,the peak of Lac and Lip higher in MRS,and the area under curve in PWI lower.For group B,there were some changes,including the intensity of T_1 weighted imaging lower,the intensity of T_2 higher,the intensity of DWI higher,the peak of Cho apparently decreasing,the peak of Cr and Glx a little lower,the peak of Lac apparently increasing in MRS and the curve in PWI flater.Conclusion:Hepatic cell apoptosis and necrosis can be gained by obstruction of blood supply of the right hepatic lobe.There are special changes in DWI,MRS,PWI,so cell apoptosis and necrosis can be detected in vivo by them.