Gadoxetic acid-enhanced MR imaging is the most useful imaging technique for evaluating small HCC, including early HCC.

Purpose: To clarify the factors that predict enhancement of the liver parenchyma in hepatocyte-phase of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA)-enhanced MR imaging. Materials and Methods:Gd-EOB-DTPA-enhanced hepatocyte-phase MR images of 198 patients with chronic liver diseases (Child-Pugh class A in 112 patients, class B in 74 patients, and class C in 12 patients) were retrospectively analyzed. The hepatocyte-phase images were obtained using fat-suppressed T1-weighted gradient-echo images with a 3D acquisition sequence 10 min and 20 min after IV administration of Gd-EOB-DTPA (0.025 mmol/kg body weight). The quantitative liver-spleen contrast ratio (Q-LSC) was calculated using the signal intensities of the liver and spleen. Serum albumin levels, total bilirubin levels, prothrombin activity, and the results of indocyanine green clearance tests (ICGs) were recorded and correlated with the Q-LSC. Logistic regression analysis was performed to analyze which factors predict sufficient liver enhancement using a Q-LSC of 1.5 as a cutoff value.Results: Only ICGs and Child-Pugh classifications showed a statistically significant correlation with the Q-LSC. Logistic regression analysis showed that ICGs were the only factors that accurately predicted liver enhancement on hepatocyte-phase images.Conclusion: ICGs were found to be predictors of sufficient liver enhancement on hepatocyte-phase images.

Purpose: To evaluate the effectiveness of diffusionweighted magnetic resonance imaging (DWI) in estimating the grade of malignancy of hepatocellular carcinoma.Materials and Methods: Dynamic contrast-enhanced computed tomography (CE-CT) and DWI (b value, 1000 s/mm 2 ) were performed on 73 patients. Using DW images, the lesions were classified as ''visible'' or ''invisible.'' The apparent diffusion coefficient (ADC) of the lesions was measured. Furthermore, the lesions were classified as hypervascular or iso-hypovascular using arterial phase CE-CT images. The image findings for each lesion type were compared.Results: The 73 patients had 98 hepatocellular lesions, of which 12 were histologically diagnosed as dysplastic nodules; 39, well-differentiated HCCs; 33, moderately differentiated HCCs; and 14, poorly differentiated HCCs. The mean ADC values of moderately poorly-differentiated HCCs were significantly lower than well-differentiated HCCs and dysplastic nodules (P < 0.01). On DW images, >90% of moderately (30/33) and poorly differentiated HCCs (13/14) were visible, while 51% of well-differentiated HCCs (20/39) and all dysplastic nodules were invisible. Of 22 iso-hypovascular lesions, 4 were visible on DW images and were poorly differentiated HCCs, whereas 18 were invisible and were dysplastic nodules (12/18) or well-differentiated HCCs (6/18). Conclusion:A combination of hypovascularity and visibility on DW images can help distinguish poorly differentiated HCCs from low-grade hepatocellular lesions (dysplastic nodules and well-differentiated HCCs).

Purpose: To compare the diagnostic accuracy of contrastenhanced computed tomography (CE-CT), contrastenhanced ultrasonography (CE-US), superparamagnetic iron oxide-enhanced magnetic resonance imaging (SPIO-MRI), and gadoxetic acid-enhanced MRI (Gd-EOB-MRI) in the evaluation of colorectal hepatic metastases. Materials and Methods:In all, 111 patients with colorectal cancers were enrolled in this study. Of the 112 metastases identified in 46 patients, 31 in 18 patients were confirmed histologically and the remaining 81 in 28 patients were confirmed by follow-up imaging. CE-CT, CE-US, SPIO-MRI, and Gd-EOB-MRI were evaluated. Mean (of three readers, except for CE-US) area under the receiver operating characteristic curve (A z ), sensitivities, and positive predictive values (PPV) were calculated. Each value was compared to the others by variance z-test or chi-square test with Bonferroni correction. Conclusion: Gd-EOB-MRI and SPIO-MRI were more accurate than CE-CT and CE-US for evaluation of liver metastasis in patients with colorectal carcinoma.

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