Purpose: To compare the diagnostic performance of gadoxetic acid-enhanced MRI with that of multi-phase 40-or 64-multidetector row computed tomography (MDCT) to evaluate viable tumors of hepatocellular carcinomas (HCCs) treated with image-guided tumor therapy. Materials and Methods:A total of 108 patients with 162 HCCs (56 lesions with viable tumor and 106 without viable tumor) treated by means of transcatheter arterial chemoembolization or radiofrequency ablation were retrospectively included in this study. All patients underwent multi-phase CT at 40-or 64-MDCT and gadoxetic acidenhanced MRI using 3.0 Tesla (T). Two observers independently and randomly reviewed the CT and MR images of the treated lesions. The diagnostic performance of two techniques for the evaluation of the viable tumors in the treated lesions was assessed with a receiver operating characteristic (ROC) analysis.Results: For each observer, the areas under the ROC curve were 0.953 and 0.969 for MRI, and 0.870 and 0.888 for MDCT (P < 0.05). The diagnostic accuracies (96.3% for each observer) and sensitivities (92.9% and 96.4%) of MRI in two observers were significantly higher than those (82.7% and 80.9%, 53.6% for each observer, respectively) of MDCT (P < 0.001). The negative predictive values (96.3% and 98.1%) of MRI in two observers were significantly higher than those (80.0% and 79.5%) of MDCT (P < 0.001). For each observer, specificities and positive predictive values did not differ significantly between the two techniques (P > 0.05). Conclusion:Gadoxetic acid-enhanced MRI shows better diagnostic performance than that of MDCT for evaluating the viable tumors of HCCs treated with image-guided tumor therapy.

Purpose: To determine histological and MR imaging differences between areas with Gd-EOB-DTPA (gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid) uptake and without in hepatocellular carcinomas (HCCs) as seen on Gd-EOB-DTPA-enhanced hepatobiliary-phase MR images. Materials and Methods:This study included nine patients with nine histopathologically proven HCCs (mean size, 1.9 cm) that consisted of two portions of a non-hypointense (Gd-EOB-DTPA uptake) and hypointense area (no Gd-EOB-DTPA uptake) in one tumor as depicted on hepatobiliary-phase MR images. Two radiologists and one pathologist compared the histological and MR finding differences between the two portions in consensus.Results: In eight specimens, non-hypointense areas of six specimens showed a green color and two specimens did not show a green color. Microscopically, two of nine showed a higher percentage of bile pigments in the nonhypointense area as compared to the hypointense area and the remaining seven showed no difference. Six were homogeneous Edmondson-Steiner grade II, and one was grade I. In two, non-hypointense areas were grade II and hypointense areas were grade I. No difference between the two portions was found for necrosis, hemorrhage, fibrosis, and a fibrous capsule. Seven on T1/T2-weighted images and eight on arterial and portal phase images showed no different signal intensity between the two portions. Conclusion:Although macroscopically, a non-hypointense area of an HCC seen on GD-EOB-DTPA-enhanced hepatobiliary-phase images may be associated with the area with a green color, no definite microscopic and MR imaging findings that could discriminate a non-hypointense from a hypointense area of an HCC was found.