Gadoxetate disodium-enhanced hepatobiliary phase MRI of hepatocellular carcinoma: Correlation with histological characteristics

OBJECTIVE. The purpose of this study was to assess whether gadoxetate disodium-enhanced hepatobiliary phase MRI could predict the histologic factors of hepatocellular carcinomas (HCCs). MATERIALS AND METHODS. Fifty-three HCCs histopathologically proved by surgery in 51 patients were evaluated retrospectively. All patients underwent gadoxetate disodium-enhanced MRI before surgical resection. The differences in contrast enhancement ratio of the lesions and differences in contrast-to-noise ratio (CNR) among the histologic grades of HCC were compared by using the Kruskal-Wallis test. The Spearman method was used to determine the correlations among contrast enhancement ratio, CNR, cell density ratio, and positivity for anti-hepatocyte antibody, keratin 7, and keratin 19. RESULTS. Of 53 HCCs, 50 showed low signal intensity on hepatobiliary phase images, whereas three HCCs were hyperintense on hepatobiliary phase images compared with surrounding hepatic parenchyma. Although well-differentiated HCCs tended to show higher contrast enhancement, there was no statistical significance between contrast enhancement ratio of the tumors and histologic grade (p = 0.414). No significant difference was observed between CNR and histologic grade (p = 0.965). The contrast enhancement ratios of the tumors were significantly lower in the keratin 19-positive group than in the keratin 19-negative group (p = 0.015). There was no significant correlation among contrast enhancement ratio, anti-hepatocyte antibody positivity, cell density ratio, and keratin 7 positivity (p > 0.05). CONCLUSION. The contrast enhancement ratio and CNR of HCCs were not correlated with histologic grades. The contrast enhancement ratio was significantly lower in keratin 19-positive HCCs.