Gadoxetic Acid-Enhanced and Diffusion-Weighted Magnetic Resonance Imaging of Histologically Defined Early Hepatocellular Carcinoma

Abstract

Purpose: To describe the imaging features of histologically defined early hepatocellular carcinoma (eHCC) on gadoxetate disodium-enhanced MRI (EOB-MRI) and diffusion-weighted imaging (DWI).Materials and Methods: We enrolled 173 surgically confirmed eHCCs in 119 patients examined by preoperative EOB-MRI and DWI between January 2006 and September 2017. The imaging features of preoperatively detected eHCCs were retrospectively analyzed by two radiologists. The clinical and imaging characteristics associated with false-negative detection were evaluated.Results: Of the 173 eHCCs, 118 (68%) in 78 patients were prospectively reported on preoperative EOB-MRI. After retrospective review, 17 eHCCs in 13 patients were additionally detected, with a per-lesion detection sensitivity of 78% (135/173). Thus, the imaging features of 135 eHCCs in 91 patients were analyzed. Most eHCCs exhibited hepatobiliary hypointensity (90%, 122/135). Arterial phase hyperenhancement, washout, and capsule appearance were seen in 68 (50%), 79 (59%), and 11 (8%) detected lesions, respectively. Diffusion restriction and fatty change were noted in 30 (22%) and 39 (29%) lesions, respectively; most eHCCs exhibited T1 and T2 isointensity (80 [59%] and 89 [66%], respectively). False-negative detection was associated with small lesion size (< 1 cm), history of HCC treatment (odds ratio, 0.34 [95% confidence interval, 0.13-0.92]), number of HCC lesions (≥ 2; odds ratio, 0.08 [0.01-0.66]), and poor functional liver imaging score (< 4; odds ratio, 0.13 [0.04-0.51]).Conclusions: Histologically defined eHCCs typically appear as hepatobiliary phase hypointensity. Detection sensitivity of eHCC may be affected by lesion size, history of HCC treatment, number of HCCs, and hepatobiliary enhancement.