低场MR平扫在肝细胞癌和肝血管瘤的诊断与鉴别诊断中的应用价值

目的探讨低场MR平扫在肝细胞癌（HCC）的诊断与鉴别诊断中的价值。方法随机抽取经手术病理证实为HCC（结节型）及血管瘤MR资料，其中HCC30例41个病灶，血管瘤20例25个病灶。两组均分别行横轴位T1WI、T2WI。分析病灶MRI特点及分别测量和计算HCC、血管瘤T1WI的信号强度（T1S）、T2WI信号强度（T2S）、及各自的对比噪声比（CNR）。结果HCC组：T1WI25个病灶（71．43％）呈稍低信号；T2WI38个病灶（92．68％）呈稍高信号；T2WI20个病灶（48．78％）周围见低信号包膜；10例（24．39％）可见门静脉癌栓；16例（16．67％）可见肝门淋巴结肿大；16例（53.33％）合并肝硬化。血管瘤组：T1WI15个病灶（65．21％）病灶为稍低信号，T2WI23个病灶（92．00％）为高信号，19个病灶（76．00％）见边缘分叶征。两组T2WI信号特征及边界征像差异比较有显著性（P〈0．05）；两组T2S、T2CNR在差异有显著性（P〈0．01）。结论低场MRI平扫显示的T2WI信号强度、假包膜征、肿瘤边界征等在HCC的诊断与鉴别诊断中有重要价值。

Diagnosis and differential diagnosis value of low-filed MR plain scanning in hepatocellular carcinoma

Objective] To evaluate the diagnosis and differential diagnosis value of low-field MR plain scanning in hepatocellular carcinoma(HCC) and hemangioma. Methods] The data of 30 patients with HCC (nodular lesions) and 20 patients with hemangioma proved by surgery and pathology were selected randomly. All patents were underwent TIWI and T2WI from a 0.2T MR system. The MRI features of all lesions were analyzed and T1WI signal (T1S) and T2WI signal (T2S) of HCC and hemangioma were measured respectively. Then the contrast to noise ratio (CNR) of HCC and hemangiomas were calculated. Results] In HCC group, 25 lesions (71.43%) showed slightly hypointensity on T1WI and 38 lesions (92.68%) showed moderate hyperintensity on T2WI; 20 lesions (48.78%) showed capsules on T2WI; 10 cases (24.39%) demonstrated portal vein tumor thrombosis; 16 cases (16.67% ) associated with lymph nodes metastases and 16 cases (53.33%) accompanied hepatic cirrhosis. In hemangiomas group, 15 lesions (65.21%) showed slightly hypointensity on T1WI and 23 lesions (92.00%) showed hyperintensity on T2WI; 19 lesions (76.00%) showed lobulated appearance. There were significant difference between the two groups in the signal characteristics on T2WI (P <0.05), the bouncary signs (P <0.05), the T2S (P <0.01) and the T2 CNR (P <0.01) of lesions. Conclusion] Low-field MR plain scanning is valuable in diagnosis and differential diagnosis of HCC in the signal of T2WI, the signs of pseudocapsule and tumor bouncary.