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

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 ( 99m Tc-GSA) scintigraphy. This retrospective study consisted of 55 and 33 patients who underwent SPIO- and Gd-EOB-DTPA-enhanced MRI in addition to 99m Tc-GSA scintigraphy, respectively. For each patient, we calculated Pre R 2* and Pre R 2, which are equivalent to R 2* (=1/ T 2*) and R 2 (=1/ T 2) values of the liver parenchyma; Δ R 2* and Δ R 2, which represent differences in R 2* and R 2 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 99m Tc-GSA scintigraphy, the receptor index LHL15 and the blood clearance index HH15 were recorded. Regression analysis showed a moderate correlation between Pre R 2* and LHL15 ( P < 0.05). Mild to moderate correlations were also obtained between any combination of Δ R 2* and Δ R 2 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). Pre R 2*, Δ R 2*, Δ R 2 and the increase rates of LSR and LMR could be used as quantitative indicators of liver function.