Feasibility of gadoxetic acid-enhanced magnetic resonance imaging for early liver graft assessment: a prospective single-center pilot study.

AIM: To evaluate the feasibility of gadoxetic acid-enhanced magnetic resonance imaging (MRI) for early functional assessment of liver grafts following orthotopic liver transplantation (OLT). METHODS: This prospective single-center pilot study enrolled 44 consecutive adults who underwent OLT at Graz University Medical Center from 2021 to 2023. The primary outcome was feasibility, defined as the completion of all scheduled MRI examinations. Standardized graft assessment included gadoxetic acid-enhanced MRI and serum liver function tests on postoperative days (POD) 3-7, 10-21, and 26-30. Hepatobiliary phase T1-weighted images were analyzed to extract the functional liver imaging score (FLIS), relative liver enhancement, and second-order texture features. Exploratory correlations between imaging parameters and serum biomarkers were assessed using Spearman rank analysis. RESULTS: MRI was feasible in 10 of 44 recipients (22.7%; 95% CI 12.7-37.0; 40% male; mean age 52.4±14.4 years). It was not feasible mainly in patients with acute kidney injury (40.9%) and MRI-incompatible implants (22.7%). In exploratory analyses, FLIS correlated negatively with total bilirubin (r=-0.77, P=0.009) and alkaline phosphatase (r=-0.75, P=0.012), and positively with cholinesterase (r=0.66, P=0.037). After correction for multiple testing, none of these correlations remained significant. At POD 3-7, 70% of patients had a FLIS≥4, suggestive of good graft function. CONCLUSION: Gadoxetic acid-enhanced MRI was feasible for early post-transplant graft assessment in only 22.7% of OLT recipients, mainly limited by acute kidney injury and MRI-incompatible devices. In eligible patients, FLIS and, to a lesser extent, texture analysis may complement serum biomarkers. These hypothesis-generating findings require validation in larger multicenter studies.