Application value of 18F-FDG PET/CT delayed imaging in diagnosis of primary liver cancer

Abstract

Objective To investigate the diagnostic value of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/CT delayed imaging in the diagnosis of primary liver cancer. Methods Clinical data of 80 patients with primary liver cancer who were admitted to the Third Affiliated Hospital of Sun Yat-sen University between October 2014 and December 2016 were retrospectively analyzed. Among them, 62 cases were males and 18 were females, aged (58±12) years old on average. According to the tumor diameter, the patients were divided into the small liver cancer group (n=30), nodular liver cancer group (n=23) and large liver cancer group (n=27). The informed consents of all patients were obtained and the local ethical committee approval was received. PET/CT early imaging was performed on the patients at 40-60 min after they were intravenously injected with contrast agent 18F-FDG, and PET/CT delayed imaging was performed at 2 h later. The maximal standardized uptake values (SUVmax) of the lesions in two imagings were detected. The early imaging, delayed imaging and the imaging changes at different stages were observed and compared among three groups. The SUVmax values were compared among three groups using one-way analysis of variance and LSD-t test, and were compared between two groups using t test. The rates were compared using Chi-square test. Results The SUVmax values of the early imaging and delayed imaging were respectively 5.1±1.9 and 5.5±2.3 in the nodular liver cancer group, significantly higher than 3.9±1.4 and 4.3±2.0 in the small liver cancer group (LSD-t=2.60, 2.03; P<0.05), whereas significantly lower than 6.9±2.6 and 8.5±2.9 in the large liver cancer group (LSD-t=-2.82, -4.08; P<0.05). The SUVmax value of the delayed imaging in the large liver cancer group was significantly higher than that of the early imaging (t=2.05, P<0.05). The percentage of patients with SUVmax values of the delayed imaging higher than that of the early imaging was 93%(25/27) in the large liver cancer group, significantly higher than 53%(16/30) in the small liver cancer group and 61%(14/23) in the nodular liver cancer group (χ2=10.85, 7.28; P<0.05). Conclusions The 18F-FDG uptake of the delayed imaging increases significantly along with the tumor diameter increases. Application of 18F-FDG PET/CT delayed imaging can elevate the detection rate of liver cancer, especially large liver cancer. Key words: Liver neoplasms; Fluorodeoxyglucose F18; Delayed imaging; Positron-emission tomography