Magnetic resonance imaging of portal vein invasion in hepatocellular carcinoma: Results from 25 cases

AIM: To pre-operatively assess tumor thromboses associated with hepatocellular carcinoma in the portal vein.METHODS: Twenty-five patients diagnosed with a thrombus due to hepatocellular carcinoma were included in the study. MR imaging was performed with a 1.0T superconducting magnetic imaging system. Both T1 and T2 weighed images as well as FLASH sequences were obtained in the transverse plane, and additional FLASH images were obtained in the coronal plane.RESULTS: Thromboses located in the portal vein had signal intensities similar to those of the main tumor. An intrinsic portal vein thrombus was found in 16 patients, and six thromboses were occlusive. Thromboses were found in the diffuse narrow portal branches of 3 patients. The portal venous thromboses displayed an area of signal intensity that replaced the normal flow void of the portal vein. The affected portal veins displayed a stumpy appearance, had irregular areas of stenosis, and showed formation of a vascular net.CONCLUSION: MRI was more sensitive, specific, and noninvasive for detecting a portal tumor thrombus, and can be used jointly with spin echo (SE) and gradient echo (GRE) imaging techniques.