动态增强MRI对肝脏良恶性肿瘤的鉴别诊断

Differential Diagnosis of Hepatic Tumors with Dynamic Gd - enhanced MR Imaging

目的:通过分析动态增强磁共振成像法对肝细胞癌、肝转移瘤及海绵状血管瘤的诊断准确性,评价其在肝脏良恶性肿瘤鉴别诊断中的价值。方法:动态增强法采用快速梯度回波(FLASH序列),以病灶为中心取矢状位或斜位成像;每次5-8层,采集时间约10-20秒,用同一序列共重复扫描9次。结果:在动态增强MRI成像中,15例肝细胞癌表现为注射造影剂后15-45秒后呈迅速、中度不均匀强化,75秒后强化迅速消退;另2例未见明显早期强化,后期仍呈低信号。肝转移瘤表现为轻度、逐渐周边强化,延时期仍呈轻度环形强化。海绵状血管瘤表现为逐渐增强的、由周边向中心扩展的显著强化,延时期仍不消退,呈显著高信号。结论:动态增强MRI能有效地显示肝脏肿瘤内的血液动力学变化,能为鉴别诊断提供可靠的依据,对肝脏肿瘤的准确诊断有极其重要的价值。

Purpose: The aim of this study was to investigate the efficacy of dynamic Gd - enhanced MR imaging in the evaluation of benign and malignant liver tumors. Methods: We have stuied 49 patients with liver tumor (HCC 17, hemangioma 24, metastatic tumor 8) using dynamic MR imaging. After intravenous bolus injection of Gd - DT-PA, serial images were obtained by using a breath - hold FLASH sequence which takes 5-8 slices for 10 - 20 seconds. The same sequence was repeated every 30 seconds for 9 times. Results: The characteristic appearance of hepatocellular carcinoma showed rapid enhancement on early arterial phase and decline on late phase images , except this, two HCC cases did not showed obvious early enhancement and remained low intensity on delayed phase . Metastatic liver tumors showed slightly peripheral enhancement on late phase images and could be noted on delayed phase images. Cavernous hemangioma was enhanced progressively from its peripheral area and obvious hy-perintensity on delayed images. Conclusion : Dynamic Gd - enhanced MR Imaging can display the hemodynamic patterns and is a useful method for the differential diagnosis of liver tumors.