MRI菲立磁增强扫描对家兔急性放射性肝损伤的评价

Acute Irradiation-Induced Hepatitis in Rabbits: Feridex-Enhanced MRI Evaluation

目的 探讨MRI菲立磁增强扫描对急性放射性肝损伤的早期诊断价值。方法 5只家兔经 40Gy单次X射线半肝照射后第 3天作MRIT2WI平扫和增强扫描 ,并将MRI表现与病理组织学检查相对照。结果 5只家兔T2WI平扫肝组织信号强度均未发现变化。T2WI菲立磁增强扫描 ,肝组织信号强度受照区与非受照区均较平扫降低 ,但受照区肝组织信号强度相对比非受照区高 ,两者间见明显的分界线。全部家兔受照区与非受照区肝组织在光镜下观察未发现充血、水肿、炎症细胞浸润及纤维化等异常改变。结论 T2WI菲立磁增强扫描在家兔半肝照射后第 3天光镜未发现组织学变化时即检出肝放射性改变 ,且表现有明确的特征性。我们认为MRIT2WI菲立磁增强扫描对放射性肝损伤的早期诊断具有重要的临床意义。

Objective To evaluate the diagnostic capability of Feridex (SPIO)-enhanced MRI at the early stage of acute irradiation-induced hepatitis. Methods Five rabbits were carried on MRI T2WI conventional and Feridex contrast-enhanced scan consequently on the third day of post-irradiation. The images were also compared with histopathologic findings. Results On plain-scanned images the signal intensity (SI) of the liver showed no abnormality, but on Feridex-enhanced MR images, livers' SI of irradiated regions were higher than non-irradiated area with delineating line between them. In microscopic study, both irradiated and non-irradiated regions showed no evidence of inflammatory cell infiltration, congestion, edema or fibrosis. Conclusion Feridex-enhanced MRI on the third day post-irradiation could detect abnormal changes of irradiation-induced hepatitis when no histopathologic changes in light microscope, and it has great value in acute irradiation-induced hepatitis diagnosis, especially at the very early stage.