Volume-assisted estimation of liver function based on Gd-EOB-DTPA–enhanced MR relaxometry

Abstract

Objectives: To determine whether liver function as determined by indocyanine green (ICG) clearance can be estimated quantitatively from hepatic magnetic resonance (MR) relaxometry with gadoxetic acid (Gd-EOB-DTPA). Methods: One hundred and seven patients underwent an ICG clearance test and Gd-EOB-DTPA–enhanced MRI, including MR relaxometry at 3 Tesla. A transverse 3D VIBE sequence with an inline T1 calculation was acquired prior to and 20 minutes post-Gd-EOB-DTPA administration. The reduction rate of T1 relaxation time (rrT1) between pre- and post-contrast images and the liver volume-assisted index of T1 reduction rate (LVrrT1) were evaluated. The plasma disappearance rate of ICG (ICG-PDR) was correlated with the liver volume (LV), rrT1 and LVrrT1, providing an MRI-based estimated ICG-PDR value (ICG-PDRest). Results: Simple linear regression model showed a significant correlation of ICG-PDR with LV (r = 0.32; p = 0.001), T1post (r = 0.65; p < 0.001) and rrT1 (r = 0.86; p < 0.001). Assessment of LV and consecutive evaluation of multiple linear regression model revealed a stronger correlation of ICG-PDR with LVrrT1 (r = 0.92; p < 0.001), allowing for the calculation of ICG-PDRest. Conclusions: Liver function as determined using ICG-PDR can be estimated quantitatively from Gd-EOB-DTPA–enhanced MR relaxometry. Volume-assisted MR relaxometry has a stronger correlation with liver function than does MR relaxometry. Key Points: • Measurement of T1 relaxation times in Gd-EOB-DTPA–enhanced MR imaging quantifies liver function. • Volume-assisted Gd-EOB-DTPA–enhanced MR relaxometry has stronger correlation with ICG-PDR than does Gd-EOB-DTPA–enhanced MR relaxometry. • Gd-EOB-DTPA–enhanced MR relaxometry may provide robust parameters for detecting and characterizing liver disease. • Gd-EOB-DTPA–enhanced MR relaxometry may be useful for monitoring liver disease progression. • Gd-EOB-DTPA–enhanced MR relaxometry has the potential to become a novel liver function index.