Determination of hepatic galactose elimination capacity using 2-[¹⁸F]fluoro-2-deoxy-d-galactose PET/CT: reproducibility of the method and metabolic heterogeneity in a normal pig liver model

Abstract

Objective A PET method is developed for non-invasive measurement of regional metabolic liver function using the galactose analog 2-[18F]fluoro-2-deoxy-D-galactose, FDGal. The aim of the present study was to determine the reproducibility of the method in pigs before translating it to human studies. Material and methods Five anesthetized pigs were studied twice within an interval of three days. A dynamic PET recording was performed with an injection of 100 MBq FDGal. Non-radioactive galactose was administered throughout the PET recordings to achieve near-saturated elimination kinetics. Arterial blood samples were collected for determination of blood concentrations of FDGal and galactose (cgal). Net metabolic clearance of FDGal, KFDGal, was calculated from linear representation of data. The approximate maximal hepatic removal rate, Vmax, of galactose (mmol/l tissue/min) was calculated as KFDGal cgal. The estimates from Day 1 and Day 2 were compared and the coefficient of variation, COV, of the estimates calculated. Functional heterogeneity in normal pig liver was evaluated as COV of the tissue concentration of radioactivity during quasi steady-state metabolism. Results There was no significant difference between Vmax from Day 1 and Day 2 (p = 0.38), and the reproducibility was good with a COV of 14% for the whole liver. In normal pig liver tissue, mean COV after an injection of FDGal was on average 15.6% with no day-to-day variation (p = 0.7). Conclusions The novel FDGal PET method for determination of hepatic metabolic function has a good reproducibility and is promising for future human studies of regional liver function.

Galactose metabolism and health

“…The distinctive hepatic capacity to retain and eliminate galactose can be used as a clinical measure of metabolic liver function [13,14]. Thus, liver failure results in galactose intolerance.…”

The potential use of 2-[18F]fluoro-2-deoxy-D-galactose as a PET/CT tracer for detection of hepatocellular carcinoma

“…A couple of decades ago, a few promising PET studies using the galactose analogue 2-[ 18 F]fluoro-2-deoxy- d -galactose (FDGal) in experimental tumour models were published [25–28] but to the best of our knowledge no FDGal PET studies of patients with HCC have been published. FDGal is a tracer for galactose metabolism and avidly accumulates in the liver compared to other tissues [29–30]. FDGal can be synthesized using commercially available kits for FDG production with only minor modifications [31] and the production can thus readily be implemented at most clinical PET facilities or distributed to other nearby centres due to the radioactive half-life of 110 minutes.…”

This month in the Scandinavian Journal of Gastroenterology

“…Serensen [10] determined the reproducibility of the galactose analog 2-[18F] fluoro-2-deoxy-D-galactose, FDGal in pigs. He found that the novel FDGal PFT method has a good reproducibility and is promising for fijture human studies of regional liver function.…”