3.0T质子MRS诊断肝脏肿瘤的应用研究

Initial Application of in vivo Proton MR Spectroscopy on Hepatic Neoplasm on 3.0T

目的:探讨正常肝脏质子MRS(1HMRS)表现,评价其诊断肝脏肿瘤的意义。材料和方法:应用3.0T磁共振仪单体素PRESS序列采集46个正常肝脏和25个肝脏肿瘤波谱。根据MR化学位移成像将正常肝脏分为无脂肪肝组(33个)和脂肪肝组(13个),分析正常肝脏胆碱(Choline,Cho)含量和肝脂肪变性的关系;以自身相对正常肝区为参照,比较肿瘤Cho、脂肪(Lipid,Lip)和水(Water,W)含量的变化。结果:正常肝脏中,脂肪肝组中8%的肝脏出现Cho峰,无脂肪肝组中85%的肝脏出现Cho峰;以自身相对正常肝区作为参照,14个肝细胞癌(HCC)中有10例病变区Cho增多;5例非HCC恶性肿瘤中1例病变区Cho增多;6例良性肿瘤中3例病变区Cho增多;14例HCC病变区和自身相对正常肝区的Cho/Lip分别为0.34±0.54和0.22±0.40,6例良性肿瘤病变区和自身相对正常肝区的Cho/Lip分别为0.13±0.12和0.32±0.60。结论:活体肝质子MRS可以定量分析Water、Lip及Cho含量,肝脂肪变性影响Cho峰的显示;出现Cho峰及Cho含量增多并非肝脏恶性肿瘤的特异表现。以自身相对正常肝区为参照,多数HCC病变区Cho含量增多,HCC的Cho/Lip相对增高,良性肿瘤Cho/Lip相对降低。

Purpose：To investigate the application of in vivo proton MR spectroscopy（^1HMRS）on normal liver and to evaluate its capability in differentiating hepatic neoplasm on 3.0T MR scanner.Materials and Methods：The spectra of 46 normal livers and 25 hepatic neoplasms were obtained using single-voxel PRESS sequence on 3.0T scanner（GE,Signa Excite 3.0 T）.The peaks of Choline（Cho）,lipid CH_2 group（Lip）and water（W）were the target metabolites on the spectrum.The correlation between Cho content and the hepatic steatosis was analyzed.The hepatic steatosis level of normal liver was judged by dual echo T1WI.On 25 hepatic neoplasms,the spectrum was acquired on the lesion and the uninvolved parenchyma,respectively.The content of Cho,Lip and Water on the lesions were compared with the uninvolved parenchyma.Results：Cho was detected on 1 of 13 normal liver with hepatic steatosis（8%）while it was detected on 28 of 33 normal liver without hepatic steatosis（85%）,which showed significant difference between the two groups（P〈0.01）.On 10 of 14 hepatocellular carcinoma（HCC）,Cho content on lesion increased when compared with the uninvolved parenchyma.Cho content increased only on 1 of 5 non-HCC malignancies and on 3 of 6 benign neoplasms.Conclusions：In vivo proton MRS is technically feasible for quantitative analysis of hepatic water and Lip and Cho contents.Cho content intends to decrease on liver with steatosis,probably indicating that the metabolism of membrane is compromised on hepatic steatosis.Cho could be detected on normal liver and hepatic benign or malignant neoplasm.Although Cho increase in most of HCC,neither its detection nor its content increase was specific to the malignant tumors.Limitation still exists in clear differentiation between benign and malignant tumors.