Utility of intracellular enhancement for improving hepatic lesion visibility at gadoxetic acid-enhanced hepatobiliary-phase MRI

Purpose To investigate the utility of the intracellular enhancement (ICE) technique that suppresses extracellular signal component for shortening the gadoxetic acid (EOB)-enhanced hepatobiliary-phase (HBP) delay time while maintaining lesion visibility. Methods In this prospective study, patients who underwent EOB-enhanced MRI were screened and those with HBP hypointense hepatic lesions were included. HBP images were acquired at 10 and 20 min post-EOB injection, with and without ICE (i + - and i - -10 and 20 min HBP). One representative lesion per patient was evaluated. The lesion-to-liver contrast ratio (CR) was calculated. Two radiologists assessed overall image quality and lesion visibility on a five-point scale. The primary outcome was lesion visibility, which was assessed qualitatively using subjective lesion visibility scores and quantitatively using CR. Differences between paired groups were determined by using a two-sided Wilcoxon signed-rank test. Results Eighty-one patients were included. Overall image quality was significantly worse with ICE at both 10- and 20-min HBP (10 min: mean 3.8 vs 3.1; 20 min: 4.0 vs 3.3; both p < 0.01). There was no significant difference in the CR between i + -10 min and i - -20 min HBP (median 1.58 vs 1.54; p = 0.48). Furthermore, lesion visibility scores on i + -10 min HBP were significantly higher than those on i - -20 min HBP (mean 4.1 vs 3.9; p < 0.01). Conclusion ICE has the potential to reduce delay time without compromising lesion visualization; however, further studies with larger sample size.