BackgroundKinetic estimation provides fitted parameters related to blood flow perfusion and fluorine-18-fluorodeoxyglucose (18F-FDG) transport and intracellular metabolism to characterize hepatocellular carcinoma (HCC) but usually requires 60 min or more for dynamic PET, which is time-consuming and impractical in a busy clinical setting and has poor patient tolerance.MethodsThis study preliminarily evaluated the equivalence of liver kinetic estimation between short-term (5-min dynamic data supplemented with 1-min static data at 60 min postinjection) and fully 60-min dynamic protocols and whether short-term18F-FDG PET-derived kinetic parameters using a three-compartment model can be used to discriminate HCC from the background liver tissue. Then, we proposed a combined model, a combination of the maximum-slope method and a three-compartment model, to improve kinetic estimation.ResultsThere is a strong correlation between the kinetic parametersK1~k3, HPI and\documentclass[12pt]{minimal}
				\usepackage{amsmath}
				\usepackage{wasysym} 
				\usepackage{amsfonts} 
				\usepackage{amssymb} 
				\usepackage{amsbsy}
				\usepackage{mathrsfs}
				\usepackage{upgreek}
				\setlength{\oddsidemargin}{-69pt}
				\begin{document}$${{\varvec{V}}}_{{\varvec{b}}}$$\end{document}Vbin the short-term and fully dynamic protocols. With the three-compartment model, HCCs were found to have higherk2, HPI andk3values than background liver tissues, whileK1,k4and\documentclass[12pt]{minimal}
				\usepackage{amsmath}
				\usepackage{wasysym} 
				\usepackage{amsfonts} 
				\usepackage{amssymb} 
				\usepackage{amsbsy}
				\usepackage{mathrsfs}
				\usepackage{upgreek}
				\setlength{\oddsidemargin}{-69pt}
				\begin{document}$${{\varvec{V}}}_{{\varvec{b}}}$$\end{document}Vbvalues were not significantly different between HCCs and background liver tissues. With the combined model, HCCs were found to have higher HPI,K1andk2,k3and\documentclass[12pt]{minimal}
				\usepackage{amsmath}
				\usepackage{wasysym} 
				\usepackage{amsfonts} 
				\usepackage{amssymb} 
				\usepackage{amsbsy}
				\usepackage{mathrsfs}
				\usepackage{upgreek}
				\setlength{\oddsidemargin}{-69pt}
				\begin{document}$${{\varvec{V}}}_{{\varvec{b}}}$$\end{document}Vbvalues than background liver tissues; however, thek4value was not significantly different between HCCs and the background liver tissues.ConclusionsShort-term PET is closely equivalent to fully dynamic PET for liver kinetic estimation. Short-term PET-derived kinetic parameters can be used to distinguish HCC from background liver tissue, and the combined model improves the kinetic estimation.Clinical relevance statementShort-term PET could be used for hepatic kinetic parameter estimation. The combined model could improve the estimation of liver kinetic parameters.Graphical AbstractSupplementary InformationThe online version contains supplementary material available at 10.1186/s13244-023-01442-5.