Imaging features of hepatocellular carcinoma with bile duct tumor thrombus：a multicenter study

Background: There are still difficult and challenging problems in diagnosis of hepatocellular carcinoma (HCC) with bile duct tumor thrombus (BDTT) before operation. This study aimed to analyze the imaging features of HCC with B1-B3 BDTT. Methods: : The clinicopathological data and imaging findings of 30 HCC patients with B1-B3 BDTT from three high-volume institutions were retrospectively reviewed. Eighteen patients underwent computed tomography (CT) scans and twelve patients underwent magnetic resonance imaging (MRI) scans before operation, respectively. The diagnosis of HCC with BDTT was confirmed by postoperative pathologic examination. Results: : According to Japanese classification, 5 patients were classified as B1 BDTT, 12 B2, 13 B3, and 82 B4, respectively. The HCC lesions were detected in all patients, and the localized bile duct dilation were detected in 28 (93.3%) patients. The BDTT was observed in all B3 patients and 3 B2 patients, but it was not observed in all B1 patients on CT or MRI. The BDTT showed relatively hypoattenuation on plain CT scans and T1W images, relatively hyperattenuation signals on T2W. The BDTT showed hyperattenuation at hepatic arterial phase with washout at portal venous phase. The localized biliary dilation showed no enhancement at hepatic arterial phase and no progressively delayed enhancement at portal venous phase, but it was more obvious at portal venous phase on CT. Conclusions: : The HCC lesions and the localized bile duct dilatation on CT or MRI scans are imaging features of HCC with BDTT, which might facilitate the early diagnosis for B1-B3 BDTT.