Purpose: To establish a simple method to evaluate the degree of liver parenchymal enhancement in the hepatobiliary phase (HP) of gadoxetic acid-enhanced magnetic resonance imaging (MRI).
Materials and methods: Subjects comprised 75 patients with or without chronic liver disease who underwent gadoxetic acid-enhanced MRI and indocyanine green retention at 15 minutes (ICG-R15). HP images were used for data analysis. In the quantitative evaluation, liver-to-phantom signal intensity (SI) ratio (LPR), liver-to-portal vein SI ratio (LPVR), and liver-to-kidney SI ratio (LKR) were calculated. In qualitative visual assessment, liver-to-portal vein contrast (LPVC) and liver-to-kidney contrast (LKC) were assessed using a 5-point scale (1, hyperintense; 2, slightly hyperintense; 3, isointense; 4, slightly hypointense; 5, hypointense). Statistical evaluations included the Spearman's rank correlation test.
Results: LPVC and LKC correlated significantly with LPR (ρ = -0.445, P < 0.001; ρ = -0.576, P < 0.001, respectively). LPVC and LKC showed significant correlations with LPVR and LKR (ρ = -0.659, P < 0.001; ρ = -0.674, P < 0.001, respectively). In addition, LPVC and LKC correlated significantly with ICG-R15 (ρ = 0.696, P < 0.001; ρ = 0.795, P < 0.001, respectively).
Conclusion: LPVC and LKC can be used as simple visual indicators to objectively assess the degree of liver parenchymal enhancement on HP of gadoxetic acid-enhanced MRI.
Copyright © 2012 Wiley Periodicals, Inc.