肝脏血管平滑肌脂肪瘤的CT及MRI征象分析

目的 分析13例肝脏血管平滑肌脂肪瘤（AML）的CT及MRI表现，进一步提高诊断准确性。方法 所有病例均经手术病理证实。12例经CT检查，其中6例做过MRI检查，仅1例只做MRI检查。平扫后行增强动脉期和门脉期扫描，5例做了延迟期扫描。MRI检查行SE T1WI、快速自旋回波（FSE）T2WI和快速多层面干扰梯度回波（FMPSPGR）序列横断面动态多期增强扫描。结果 CT平扫11个病灶为低密度，1个为略高密度。动脉期所有病灶均有强化表现，8个病灶见到中心血管影。门脉期8个病灶有持续强化，有6个病灶见到中心血管影。MR T1WI上5个病灶为混杂信号，T2WI上所有病灶均为高信号，但信号强度各不相同。MR增强动脉期6个病灶有强化，1个病灶强化不明显。门脉期4个病灶有持续强化，3个为低信号。MR增强扫描中也有4个病灶显示中心血管影。结论 CT和MRI检查均可显示AML的特征，特别是病灶中脂肪成分和血管影高度提示AML的诊断。MR SE序列加脂肪抑制显示脂肪成分比CT更加敏感。CT和MR动态增强多期扫描可充分反映AML的强化特征，有助于提高AML的诊断准确性。

The analysis of CT and MRI appearances of hepatic angiomyolipomas

Objective To analyze the variable appearances of hepatic angiomyolipomas on CT and MRI, and to improve the diagnostic accuracy with CT and MRI. Methods All 13 cases were proved by surgical pathology. Helical CT scanning of pre- and post-contrast arterial phase, portal venous phase were performed in 12 cases, delayed phase scanning was performed in 5 of 12 cases. Magnetic resonance imaging with SE T 1WI, FSE T 2WI, and FMPSPGR axial dynamic multi-phase contrast scanning were performed in 7 cases. Results On pre-contrast CT scans, 11 of 12 lesions appeared as hypodensity, the other one appeared as slight hyperdensity. On the arterial phase scans, all lesions were markedly enhanced, the central vascular structure could be seen in 8 lesions. On the portal venous phase, 8 lesions remained enhanced and the central vascular structure could also be seen in 6 lesions. 5 of 7 lesions showed inhomogeneous hypointensity on SE T 1WI, and all of 7 lesions showed hyperintensity (from slight hyperintensity to strong hyperintensity) on FSE T 2WI. 6 lesions showed enhancement on the MR arterial phase scans, the other one showed no marked enhancement because the most parts of the lesion were fat. 4 lesions showed prolonged enhancement on the portal venous phase, and the other 3 lesions showed hypointensity. The central vascular structure could also be seen in 4 of 7 lesions on MR contrast dynamic scanning. Conclusion Both CT and MR could demonstrate the characterization of hepatic angiomyolipomas, especially the central vascular structure in the lesions strongly hint the diagnosis of angiomyolipomas. MR SE sequence with fat suppression is more sensitive than CT in the demonstration of the fat. CT and MR dynamic multi-phase contrast scanning can fully reflect the characterization of hepatic angiomyolipomas and can be helpful to improve the diagnostic accuracy.