不同阶段放射性肝脏损伤的MRI表现

MRI Image Appearance of Different Phase of Radiation-induced Hepatic Injury

目的探讨立体定向放射治疗后不同阶段肝脏损伤的MRI表现。方法回顾性分析36名原发性肝癌经立体定向放射治疗后行MRI复查的患者,观察不同阶段放射性肝损伤T1WI、T2WI信号特点和动态增强的强化方式并计算其放射治疗后的间隔时间。结果在平扫T1WI上,放射性肝损伤区域呈低信号是53人次,平均间隔时间为85±32天,呈等信号的是9人次,平均间隔时间为26±14天;在T2WI像上,放射性肝损伤区域呈等信号的是12人次,平均间隔时间为28±18天,呈高信号的是50人次,平均间隔时间为98±43天。在T1WI动态增强上,动静脉期无强化(Ⅰ型)是12人次,平均间隔时间为32±18天;在动脉期轻度增强,呈低或稍高信号,静脉期有增强呈等或稍高信号(Ⅱ型)是15人次,平均间隔时间为92±35天;动静脉期明显增强都呈高信号(Ⅲ型)的是35人次,平均间隔时间为110±72天,Ⅰ型与Ⅱ型、Ⅲ型的间隔时间相比有显著性差异,Ⅱ型与Ⅲ型的间隔时间无显著性差异。结论放射性肝损伤因时间不同而呈不同的强化特点,推测是对放射性肝损伤不同阶段的反映,对鉴别放射性肝损伤不同阶段有重要意义。

Objective ： To evaluate the plain and dynamic enhanced MRI appearance of radiation-induced hepatic injury after three-dimensional conformal radiotherapy （stereotactic operation）. Methods： The plain and dynamic enhanced MRI images of 36 patients with. hepatocellular carcinomas after hepatic irradiation were retrospectively reviewed. The T1WI,T2WI intensity and dynamic enhanced patterns of hepatic irradiation were observed ,the interval between completion of radiotherapy and the appearance of different types of MR findings was calculated and compared the statistical difference. Results ： The irradiatied area of the liver was hypointense on T1WI images in 53 cases and isointense on T1WI images in 9 cases,the mean interval was 85 ±32, 26±14 days respectively.The irradiated area of the liver was hyperintense on T2WI images in 50 cases and isointense in 8 cases,the mean interval was 98 ±43, 28 ±18days respectively .In contrast enhanced dynamic studies ,no enhancement in arterial and portal phase（type Ⅰ ）was 12 cases,slight enhancement in arterial phase and slight or intense enhancement （type Ⅱ）was 15cases,intense enhancement in arterial and portal phase（typeⅢ）was 35cases,the interval between completion of radiotherapy and the appearance of different types of dynamic enhancement images was32± 18,92± 35,110±72 days. The difference in interval between type Ⅰ and type Ⅱ,typeⅢ was significant ,The difference in interval between type Ⅱ and type Ⅲ findings was not significant .Conclusion： Dynamic enhanced and unenhanced MR imaging can reflect the pathological background of radiation-induce hepatic injuries in every phases and have important value in the differentiation of different phases of radiation-induce hepatic injuries.