Mass-forming intrahepatic cholangiocarcinoma: Enhancement patterns in the arterial phase of dynamic hepatic CT - Correlation with clinicopathological findings.

OBJECTIVES: To evaluate the relationship between the enhancement pattern of intrahepatic cholangiocarcinomas (ICCs) in the hepatic arterial phase (HAP) of dynamic hepatic CT and the clinicopathological findings with special reference to the perihilar type and the peripheral type. METHODS: Forty-seven patients with pathologically proven ICCs were enrolled. Based on the enhancement pattern in the HAP, the lesions were classified into three groups: a hypovascular group (n=13), rim-enhancement group (n=18), and hypervascular group (n=16). The clinicopathological findings were compared among the three groups. RESULTS: Perihilar-type ICCs were significantly more frequently observed in the hypovascular group than in the rim-enhancement and hypervascular groups (p=0.006 and p <0.001, respectively). Lymphatic invasion, perineural invasion, and biliary invasion were significantly more frequent in the hypovascular group than the rim- enhancement group (p=0.001, p=0.025 and p=0.029, respectively) or hypervascular group (p <0.001, p <0.001 and p=0.025, respectively). Patients with hypovascular lesions showed significantly poorer disease-free survival than patients with rim-enhancing or hypervascular lesions (p=0.001 and p=0.001, respectively). Hypovascularity was an independent preoperative prognostic factor for disease-free survival (p<0.001). CONCLUSIONS: Hypovascular ICCs in the HAP tend to be of perihilar type and to have more malignant potential than other ICCs. KEY POINTS: • Hypovascular ICCs have greater malignant potential than rim-enhancing and hypervascular ICCs. • Hypovascular ICCs show a higher frequency of perihilar-type ICCs. • Perihilar-type ICCs do not always display distal ductal wall thickening.

Hepatocellular carcinoma: clinical significance of signal heterogeneity in the hepatobiliary phase of gadoxetic acid-enhanced MR imaging.

OBJECTIVES: To clarify the relationship between the biological behaviour of hepatocellular carcinomas (HCCs) and their signal intensity in the hepatobiliary phase of gadoxetic acid-enhanced MR imaging with a special focus on the signal heterogeneity. METHODS: A total of 68 patients with 70 pathologically proven HCCs were enrolled. On the basis of the signal intensity in the hepatobiliary phase, the lesions were classified into three groups: group 1, homogeneous hypointensity (n = 44); group 2, heterogeneous hyperintensity (n = 20); and group 3, homogeneous hyperintensity (n = 6). The clinicopathological findings were compared among the three groups. RESULTS: The tumour size and the serum level of protein induced by vitamin K absence or antagonist-II (PIVKA-II) were significantly higher in group 2 compared to group 1 (p = 0.0155, p = 0.0215, respectively) and compared to group 3 (p = 0.0330, p = 0.0220, respectively). The organic anion transporting polypeptide 8 (OATP8) expression in group 2 and group 3 was significantly higher than in group 1 (p < 0.0001, p < 0.0001, respectively). Group 2 showed a significantly lower disease-free survival rate compared to group 1 (p = 0.0125), and group 2 was an independent prognostic factor for disease-free survival (p = 0.0308). CONCLUSIONS: HCCs in the hepatobiliary phase that are heterogeneously hyperintense on gadoxetic acid-enhanced MR imaging have more malignant potential than other types of HCCs. KEY POINTS: • Heterogeneous uptake of gadoxetic acid suggests more malignant potential in HCC • Uptake of gadoxetic acid does not suggest less malignancy in HCC • Evaluation of signal heterogeneity on gadoxetic acid-enhanced MR imaging is useful.