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1937. Volumetric Whole-Liver CT Perfusion in Liver Transplant Patients
Authors * Denotes Presenting Author
  1. Ankur Pandey *; University of Maryland Medical Center
  2. Barton Lane; University of Maryland Medical Center
Objective:
To (1) Assess the feasibility of CT perfusion as a diagnostic tool in evaluating liver transplant (LT) patients, prior to and following orthotopic LT; (2) Quantify baseline perfusion in normal and cirrhotic livers; and (3) Quantify perfusion changes in transplanted livers, assessed over multiple time points to establish time course of perfusion normalization.

Materials and Methods:
This is a prospective study including potential LT donors (control group; n=6), and split (SL, n=2) and cadaveric (CL, n=10) LT recipients between 2017 and 2019. Subjects were scanned prior to LT, within 14 days (FU1), between 6-10 weeks (FU2) and 6 months (FU3) after LT. Same CT scanner was used with a whole-organ jog-shuttle technique and continuous table motion while free breathing, with 12 acquisitions after 40 mL contrast injection. Volumetric perfusion parameters including blood flow (BF), blood volume (BV), mean transit time (MTT), portal liver perfusion (PVP), arterial liver perfusion (ALP), and hepatic perfusion index (HPI) were calculated both for whole liver and segments. P<0.05 was considered significant.

Results:
Eighteen patients completed CT perfusion scans without complications. Before LT, HPI was higher (38.5 vs. 19.1%; P=0.041), ALP tended to be higher (18.8 vs. 11.7 mL/100mL/min; P=0.289) and PVP tended to be lower (55.3 vs. 68.5 mL/100mL/min; P=0.385) in cirrhotic livers compared to normal livers for whole liver volume, with similar trend for hepatic segments. On FU1, CL demonstrated higher BF (84.8 vs. 61.2 mL/100mL/min; P=0.048), ALP (20.7 vs. 11.7 mL/100mL/min; P=0.032) and HPI (36.4 vs. 19.1%; P=0.023). These parameters approached normal perfusion parameters on FU2 ([BFD, 68.0 mL/100mL/min; P=0.651], [ALP, 10.3 mL/100mL/min; P=0.643], [HPI, 21.3%; P=0.692]), and FU3 ([BFD, 62.6 mL/100mL/min; P=0.913], [ALP, 9.7 mL/100mL/min; P=0.389], [HPI, 30.9%, P=0.459]).

Conclusion:
CT perfusion was successful in evaluating normal hemodynamic changes in cadaveric liver grafts with initial expected change in perfusion at immediate FU, and near normalization on subsequent FU. To our knowledge, this is the first study on hemodynamic changes of liver transplants at multiple time points (days, weeks and months following transplant). CT perfusion is feasible in liver transplant patients. Understanding hepatic perfusion changes over time after transplant may allow earlier detection of post-transplant vascular complications.