混合型肝癌的MRI表现与病理分型的对照分析

The correlation of MRI findings with pathologic features in combined hepatocellular-cholangiocarcinoma

目的 探讨不同病理分型混合型肝癌（cHCC-CC）的MRI表现.方法 回顾性分析经手术病理证实为cHCC-CC的29例患者资料,经典型20例（24个病灶）,干细胞型9例（10个病灶）.患者术前行肝脏MRI平扫及增强扫描检查.观察病灶的形态特征、信号特征,并测量17例（22个病灶）的ADC值.采用独立样本t检验和Fisher确切概率法比较经典型及干细胞型cHCC-CC患者间影像表现的差异.结果 经典型和干细胞型cHCC-CC的最大径分别为（3.8±2.5）、（4.5±1.8）cm,差异无统计学意义（t=0.749,P=0.462）.7个病灶T1WI为不均匀高信号,27个病灶T1WI为低信号.17个病灶T2WI以中央低信号为主,为高低混杂信号.增强扫描动脉期21个病灶表现为周边环形强化,13个病灶表现为弥漫不均匀强化.17个病灶强化方式表现为快进快出,17个表现为反转强化.25个病灶可见假包膜.经典型和干细胞型cHCC-CC的动脉强化方式和胆管扩张差异有统计学意义（P均〈0.05）,形状、边界、T1WI高信号、T2WI低信号、病灶内脂肪、淋巴结肿大、强化类型、假包膜和静脉癌栓发生率差异均无统计学意义（P均〉0.05）.cHCC-CC病灶DWI均表现为高信号,经典型和干细胞型cHCC-CC病灶的ADC值分别为（1.60±0.39）×10-3、（1.41±0.52）×10^-3mm^2/s,二者差异无统计学意义（t=-1.005,P=0.326）.结论 cHCC-CC的MRI表现具有一定特征性,但依靠MRI表现不易区分经典型和干细胞型cHCC-CC.

Objective To investigate the MRI findings of combined hepatocellular cholangio-carcinoma（cHCC-CC）and their correlation with pathologic types. Methods Twenty-nine patients with surgical pathology-confirmed cHCC-CC（20 patients with 24 cHCC-CCs were categorized as classical, and 9 patients with 10 cHCC-CCs as subtypes with stem cell features）were retrospectively analyzed. The clinical features, morphological and MRI signal characteristics on T1WI, T2WI, dynamic enhancement patterns and diffusion-weighted imaging were evaluated in detail and compared these imaging findings with pathologic types. The ADC values of 17 patients with 24 cHCC-CCs were measured. The imaging features were compared by using t test and Fisher test. Results The average maximum diameter of classical type and stem cell feature type were （3.8 ± 2.5） cm and （4.5 ± 1.8） cm, respectively, there was no significant difference（t=0.749,P=0.462）. Seven cHCC-CCs showed heterogeneously high signal and twenty-seven cHCC-CCs showed low signal on T1WI. Seventeen cHCC-CCs showed hypointense in the central with mixed high and low signal on T2WI. Twenty-one cHCC-CCs showed peripheral enhancement and 13 lesions showed heterogeneously enhancement during arterial phase. The enhancement pattern of quickly wash-in and quickly wash-out were seen in 17 lesions, the other 17 lesions showed reversal enhancement. Twenty-five lesions presented with pseucapsule. There was no significant difference in clinical features and MRI findings between the two pathologic tumor types（classical type versus stem cell feature type）except for the enhancement pattern in arterial phase and peri-tumoral bile duct dilatation（P〈0.05）.The mean ADC value of the tumors with stem cell feature type（1.41 ± 0.52） × 10^-3mm^2/s was mildly lower than that of classical type （1.60 ± 0.39） × 10^-3mm^2/s, and no statistical differences were found（t=-1.005,P=0.326）. Conclusions The MRI findings of cHCC-CCs has specificity. However, it is not easy to distinguish the classical type and stem cell feature type of cHCC-CC only by MRI findings.