Effect of steatosis on liver signal and enhancement on multiphasic contrast-enhanced magnetic resonance imaging

Purpose To investigate the effect of steatosis on liver signal and enhancement in multiphasic contrast-enhanced (MCE) MRI. Materials and methods In this IRB-approved, HIPAA-compliant, retrospective, observational study, 1217 MCE abdominal MRIs performed during 2014 at a single institution were reviewed. Of these, 1085 were excluded, due to potential factors other than steatosis that may affect liver signal intensity and/or enhancement. In the remaining 132, liver fat fraction (FF) was calculated from the in- and opposed-phase 2D T1-weighted images. Liver signal intensity, absolute enhancement, and relative enhancement on fat-suppressed (Dixon method) 3D T1-weighted images before and after injection of gadobutrol (arterial, portal venous, and equilibrium phases) were plotted against co-localized FF values and the linear trend was evaluated by Pearson correlation coefficient ( r ). P values <0.05 were considered statistically significant. Results Liver signal intensity negatively correlated with FF for all phases ( r = −0.388 to −0.544, p < 0.001). Absolute enhancement negatively correlated with FF for the portal venous and equilibrium phases ( r = −0.286 and −0.289, respectively, p < 0.001), but not for the arterial phase ( r = −0.042, p = 0.632). Relative enhancement did not significantly correlate with FF for any phase ( p ≥ 0.125). Conclusion Steatosis reduces liver signal intensity in MCE MRI. This effect of steatosis was reduced in calculated absolute enhancement and eliminated in calculated relative enhancement.