Comparison of (18F)FDG PET/CT and (68Ga)DOTATATE PET/CT imaging methods in terms of detection of histological subtype and related SUVmax values in patients with pulmonary carcinoid tumors

Objective This study was designed to compare the 18-Fluorodeoxyglucose positron emission tomography/computed tomography [(F-18)FDG PET/CT] and 1,4,7,10-tetraazacyclododecane-NI,NII,NIII,NIIII-tetraacetic acid (D)-Phe1-thy3-octreotate [(Ga-68)DOTATATE PET/CT) findings in patients with pulmonary carcinoid (PC) tumors. Materials and methods A total of 20 patients [mean (SD) age: 52.2 (12.9) years, 60% women] with PC tumors and available records on digital images of (F-18)FDG PET/CT and (Ga-68)DOTATATE PET/CT and histopathological analysis were included in this retrospective single-center study. Patient characteristics, structural and functional imaging, and final histopathology were recorded in all patients. Typical and atypical PC tumors were compared in terms of patient age, tumor site, tumor size, and SUV max values obtained by (F-18)FDG PET/CT and (Ga-68)DOTATATE PET/CT imaging. Results Overall, median (minimum-maximum) SUVmax values were 3.2 (1.2-11.2) in (F-18)FDG PET/CT and 17.2 (2.5-89.0) in (Ga-68)DOTATATE PET/CT. Atypical PC tumor was associated with significantly higher mean +/- SD age (64.6 +/- 5.4 vs. 45.5 +/- 10.5 years, P=0.036) and median (minimum-maximum) (F-18)FDG PET/CT SUVmax values [7.3 (4.8-11.2) vs. 2.4 (1.2-3.9), P=0.003], but with significantly lower median (minimum-maximum) (Ga-68)DOTATATE PET/CT SUVmax values [6.4 (2.5-10.6) vs. 23.7 (14.2-89), P<0.001], compared with typical PC tumor. (F-18)FDG PET/CT and (Ga-68)DOTATATE PET/CT SUVmax values were negatively correlated (r=-0.429, P=0.011). Conclusion Our findings in patients with histologically proven PC tumors showed higher SUV max values for (F-18)FDG PET/CT in atypical PC tumors and for (Ga-68)DOTATATE PET/CT in typical PC tumors. Our findings indicate the likelihood of higher detection rates particularly for typical PC tumors by (Ga-68)DOTATATE PET/CT imaging and the potential utility of the SUVmax ratio in predicting the histological subtype of PC tumors.