MRI动态增强结合扩散成像对肝小血管瘤(≤2cm)诊断价值的研究  

Study of Diagnostic Values of Dynamic MRI and Diffusion Weighted Imaging in Small Hepatic Hemangiomas( ≤2 cm)

作　　者：盛若凡[1] 曾蒙苏[1] 姚秀忠[1] 饶圣祥[1] 

机构地区：[1]上海复旦大学附属中山医院放射诊断科,上海市影像医学研究所,200032

出　　处：《临床放射学杂志》2013年第9期1280-1285,共6页Journal of Clinical Radiology

摘　　要：目的分析肝脏小血管瘤(≤2 cm)的MRI动态增强及扩散成像表现特点,以帮助临床诊断。方法回顾性研究经病理证实的30例患者42个肝脏小血管瘤病灶,根据动态增强特征将其分为典型(Ⅰ型)、高灌注型(Ⅱ型)、非典型(Ⅲ型)三型。分别观测其MRI平扫、动态增强扫描、扩散成像表现并进行定量分析,进而综合评价各型小血管瘤的MRI表现特点及鉴别诊断要点。结果动态增强中,Ⅰ型小血管瘤(21例)各期均呈相对高信号,以缓升缓降型持续强化为主;Ⅱ型小血管瘤(7例)各期均呈相对高信号,以速升缓降型持续强化为主;Ⅲ型小血管瘤(14例)持续呈相对低信号,以低度延迟强化为主。Ⅱ型小血管瘤与门静脉在动态增强各期信噪比无统计学差异,而Ⅰ、Ⅲ型小血管瘤与门静脉间存在统计学差异(P=0.046及P=0.002)。扩散成像中,小血管瘤的信号均明显高于肝实质,但三型间信号无统计学差异;肝小血管瘤总体上具有较肝组织高的表观扩散系数(ADC)值,Ⅱ型平均ADC值高于Ⅰ型及Ⅲ型(P=0.0034)。结论各型肝小血管瘤的MRI表现具有一定特征性,MRI动态增强扫描、扩散成像、ADC值测定等对于肝脏小血管瘤的诊断及鉴别具有重要作用。Objective To analyze the features of dynamic MRI and diffusion weighted imaging of small hepatic hemangiomas（ ≤2 cm）. Methods MR images of 30 patients with 42 pathologically confirmed small hepatic hemangiomas were retrospectively analyzed. Hemangiomas were classified into 3 types based on their dynamic enhanced patterns： type I , typical hemangiomas; type U , high flow hemangiomas; and type m, atypical hemangiomas. All of them underwent MR imaging including plain T1 weighted imaging, T2 weighted imaging, dynamic contrast enhanced scanning, and diffusion weighted imaging. Signal to noise ratios of hemangiomas and the portal vein, lesion to liver contrast to noise ratios, ADCs of hemangiomas, lesion to liver signal ratios in DWI were assessed in order to generalize the MRI features and key points in differential diagnosis of small hepatic hemangiomas. Results In dynamic contrast enhanced scanning, type I hemangiomas （ n = 21 ） showed relatively high signals in all three phases and the signals rose and dropped slowly. Type II hemangiomas （nn = 7 ） showed relatively high signals in all phases and the signals rose rapidly and dropped slowly. Type III hemangiomas （ n = 14） were barely enhanced and kept hypointense most of time, and might show a faint enhancement on delayed phase. There were no significant differences in signal to noise ratios between type II hemangiomas and the portal vein in all three phases, while differences existed between type I , type III hemangiomas and the portal vein（ P = 0. 046 and P = 0. 002）. In DWI, the signal intensities and ADCs of hemangiomas were higher than those of liver parenchyma, and mean ADCs were higher in type II hemangiomas than type I and type III （ P = 0.0034）. Conclusion There are certain characteristics in MR images of small hepatic hemangiomas, dynamic contrast enhanced scanning, diffusion weighted imaging and evaluation of the ADCs play important roles in the diagnosis and differential diagnosis of them.

关 键 词：肝脏 血管瘤 磁共振成像 扩散加权 

分 类 号：R735.7[医药卫生—肿瘤]