Assessment of Hepatic Extraction Fraction and Input Relative Blood Flow Using Dynamic Hepatocyte-Specific Contrast-Enhanced MRI

Purpose: To assess the feasibility to use dynamic hepatocyte-specific contrast-enhanced MRI (DHCE-MRI) as all imaging-based liver function test, and to compare two methods for deconvolutional analysis (DA) in healthy human subjects. Materials and Methods: T(1)-weighted DHCE-MRI with the hepatocyte-specific contrast medium Gd-EOB-DTPA was performed in 20 healthy volunteers. DA was performed using truncated singular value decomposition (TSVD) and Fourier analysis with art appended tail (FA+Tail). Hepatic extraction fraction (HEF) and input relative blood flow (irBF) were calculated for each liver segment. A computer simulation comparing the standard deviation (SD) of TSVD and FA+tail at different levels of signal-to-noise(SNR) ratio was performed. The results obtained were compared using descriptive statistics, the Wilcoxon matched pairs test and the variance ratio test. Results: Median HEF was 0.201 and 0.205 using TSVD and FA+tail, respectively (P=0.086). The corresponding results for irBF was 0.240 and 0.239 (P=0.51). TSVD yielded a smaller SD, although the difference was not significant (P=0.068 for HEF and P=0.84 for irBF). The computer simulation showed that TSVD is more stable than FA+tail at most levels of SNR. Conclusion: DHCE-MRI with Gd-EOB-DTPA enables the calculation of HEF and irBF. We regard these parameters as being markers of hepatic parenchymal function.