二乙基亚硝胺诱导大鼠肝细胞癌系列病理改变及其磁共振成像

目的　探讨新型 1 5T双梯度多通道临床磁共振机对二乙基亚硝胺 (DEN)诱发大鼠肝癌模型肝脏系列病理变化的成像效果 ,并对该技术的价值及前景进行初步探讨。方法　雄性Wistar大鼠 4 0只 ,对其中 30只实施DEN干预 ,另外 10只作为对照 ,根据前期实验的病理结果确定该模型干预期为 14周 ,扫描采样时段在第7～ 2 0周 ,其中 7～ 13周为早期 ,14～ 2 0周为晚期。每 2周随机抽取干预组大鼠 4只、正常组 1～ 2只进行磁共振扫描。采用 3英寸表面线圈 ,并在控制呼吸伪影方面采取了一些措施。于扫描次日处死动物 ,选择性分区取样分析了 72个结节。结合病理检查结果 ,对不同阶段的磁共振显示效果进行分析。结果　实验中有 4只干预组大鼠意外死亡。干预组 2 6只、对照组 10只被完整实施相应的处置。在早、晚期中包含的干预组及对照组大鼠数分别为 14、5只和 12、5只 ,在晚期干预组中 8只有肝癌结节出现 ,其直径可达 2 0mm以上。对这 36只进行的磁共振扫描显示 ,在大鼠的肝癌演进过程中 ,先后有肝组织中毒性炎症、轻度纤维化、肝再生结节 (RN)的形成、肝变异结节 (DN)及癌结节 (HCC)的出现等改变。对 72个不同性质结节的分析显示 ,在T1WI上HCC以低信号为主 (7/11) ,但部分DN也可以呈低信号 (4/ 18) ;T2 WI可以显示更多?

Serial pathological changes and magnetic resonance imagings of diethylnitrosamine-induced hepatocellular carcinoma in rats

Objective To analyze the serial changes in the diethylnitrosamine (DEN)-induced rat hepatocellular carcinoma (HCC) model by a clinical dual-gradient 1.5 T magnetic resonance (MR), and discuss the value and foreground of this technique.Methods DEN-induced rat HCC models (n=30) and controls (n=10) were the candidates.According to the pathologic changes shown in the pre-experiment, between the week 7 to week 20 (early period week 7～13 and late period week 14～20),4 DEN-induced rats and 1 or 2 controls were randomly scanned every two weeks before killing them and dissecting their livers.A 3-inch surface coil was used,and some methods had been taken for decreasing the influence of respiratory false image (artefact).Seventy-two chosen nodules from zone sampling were analyzed.Results Four rats of DEN-induced group died before scanning;26 DEN-induced rats (14 in early and 12 in late period) and 10 control rats (5 in each period) completed their trial.Of the 12 treated rats in late group,8 showed hepatoma nodes.In the hepatocarcinogenesis the toxic hepatitis and hepatic fibrosis,regenerative nodule,as well as dysplastic nodules (DN) and carcinous nodules could be found sequentially.Based on the analysis of 72 nodules,the T 1WI showed hypointense lesions on most of the HCC (7/11) and some DN (4/18).The T 2WI could show more nodules,but not suitable for differentiation.Conclusion DEN-induced rat HCC model is suitable for the medical imaging study.This new 1.5T MR scanner can demonstrate the serial changes of the liver, but has limited value in the classification of nodules.Combining with other techniques it will be very helpful.