Comparison of different kinetic models for dynamic ¹⁸F-FDG PET/CT imaging of hepatocellular carcinoma with various, also dual-blood input function

Abstract

A kinetic modeling analysis was performed on hepatocellular carcinoma (HCC) as well as healthy liver tissue regions from dynamic FDG positron emission tomographys/computer tomography (PET/CT) cans. On basis of image derived input function from hepatic artery and portal vein, various kinetic models were compared among each other in order to check whether HCC can be classified and differ from healthy tissue within the kinetic parameters. 14 HCC and 10 healthy liver regions from FDG PET/CT scans of ten patients were analyzed from their time activity curves (TACs) were extracted from the PET dynamic images. Also the hepatic artery and the portal vein were delineated in the fused PET/CT images, which were used as input functions. Four kinetic models were applied to the TACs, using both or only one input function. Results were analyzed with several information criteria according to Akaike and Schwartz as well as be the F-Test. The paired student’s t-test was used to determine the differences between HCC and healthy regions. All applied models revealed significant differences of p < 0.01 of k3 between HCC and healthy liver and three out of four models produced almost identical values for k3 = 0.03 min−1 and Ki = 0.03 min−1. According to the information criteria tests, a simple two-tissue model with only a venous input function is clearly preferred in case of HCC TACs. After dividing all HCC regions into two groups having a low and a high HCC-to-healthy ratio, respectively, this model also showed significant differences of k3 between these two groups. In conclusion, results indicate that the portal vein is sufficient to describe kinetic FDG processes in HCC and healthy liver regions.

Comparison of different kinetic models for dynamic 68Ga-FAPI-04 PET/CT imaging of hepatocellular carcinoma with various, also dual-blood input function

“…As already found in the case of FDG [6], the best-preferred model is a simple two-compartment model with only a venous input function, suggesting that the lesions are mainly supplied by the hepatic artery. Since this is a methodological study, no corrections for partial volume or motion effects have been applied, therefore all rate constant values, especially for K1 and k 2 , cannot be taken as absolute numbers.…”

“…Although the liver was supplied by a venous and arterial input [7], it was recently shown [6] that the portal vein was sufficient to classify kinetic processes of FDG. Five models were applied to all TACs ( Figure 2) : two two-compartment with one input function from the aorta.…”

“…In model A-4, four rate constants K 1 , k 2 , k 3 and k 4 were used; for model A-3 three rate constants K 1 , k 2 and k 3 . The third model used both input functions from aorta and portal vein according to the formulas [6]. The fourth and fifth model, denoted as V-4 and V-3, were identical to models A-4 and A-3, except the portal vein was used as input function instead of the aorta.…”

“…The average and standard deviation of the rate constants, including K i = K 1 k 3 /(k 2 +k 3 ), was calculated for all TACs, uncertainties of the fit parameters were obtained from the calculated covariance matrix and the residual sum of squares weighted by a factor for time frames (WRSS) was calculated. The initial parameters were chosen according to Geist et al [6]. The size of the delineated volume and SUV from the last 10 minutes was calculated.…”

“…Recently, its quinoline-based derivatives have been designed into radiopharmaceutical agents, showing superior tumor-imaging potential of FAPI in different tumor entities [3,4] Dynamic PET might have potential in differential diagnosis other than static imaging [5]. We previously introduced a simple two-tissue model using the portal vein solely to differentiate HCC from healthy liver tissues [6]. The objective of this study was to establish a 68 Ga-FAPI-04 dynamic model in hepatic lesions and to assess dynamic FAPI PET to recognize HCC lesions.…”