Quantitative analysis of liver function using superparamagnetic iron oxide- and Gd-EOB-DTPA-enhanced MRI: Comparison with Technetium-99m galactosyl serum albumin scintigraphy

Purpose: To examine whether or not the parameters regarding the signal intensity of the liver parenchyma on superparamagnetic iron oxide (SPIO)- and gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI are correlated with the parameters of Technetium-99m galactosyl serum albumin (Tc-99m-GSA) scintigraphy. Materials and methods: This retrospective study consisted of 55 and 33 patients who underwent SPIO- and Gd-EOB-DTPA-enhanced MRI in addition to Tc-99m-GSA scintigraphy, respectively. For each patient, we calculated Pre R2* and Pre R2, which are equivalent to R2* (= 1/T2*) and R2 (= 1/T2) values of the liver parenchyma; Delta R2* and Delta R2, which represent differences in R2* and R2 values of the liver parenchyma before and after administration of SPIO; and the increase rates of both the liver-to-spleen signal intensity ratio (LSR) and the liver-to-major psoas muscle signal intensity ratio (LMR) on the hepatobiliary phase compared with the precontrast image. For Tc-99m-GSA scintigraphy, the receptor index LHL15 and the blood clearance index HH15 were recorded. Results: Regression analysis showed a moderate correlation between Pre R2* and LHL15 (P < 0.05). Mild to moderate correlations were also obtained between any combination of Delta R2* and Delta R2 on the one hand, and LHL15 and HH15 on the other (P < 0.05). There were moderate correlations between any combination of increase rates of LSR and LMR on the one hand, and LHL15 and HH15 on the other (P < 0.05-0.001). Conclusion: Pre R2*, Delta R2*, Delta R2 and the increase rates of LSR and LMR could be used as quantitative indicators of liver function. (C) 2011 Elsevier Ireland Ltd. All rights reserved.