The Value Of Dual-time-point¹⁸F-FDG PET/CT In Differentiation Of Malignant From Benign Colorectal Diseases

Objective:To explore the value of dual-time-point18F-FDG PET/CT in differentiation of malignant from benign colorectal diseases by analyzing PET/CT imaging of58patients with colorectal diseases.Methods:(1)According to pathological diagnostic results and follow-up results,58patients with colorectal diseases were recruited for the study. We retrospectively analyzed their early18F-FDG PET/CT imaging and delayed18F-FDG PET/CT imaging by using ROI technology measuring maximum standardized uptake values (SUVmax) of colorectal lesions. The SUVmax of the two acquisition were signed SUVearly and SUVdelayed respectively. Then calculate the change of SUVmax(Δ SUV).(2)Compare the differences between the malignant diseases and the benign diseases of SUVearly, SUVdelayed and Δ SUV respectively.(3)Compare the differences between SUVearly and SUVdelayed of the malignant diseases and the benign diseases.(4)Draw the ROC curve based on the SUVearly, SUVdelayed and Δ SUV to find the best differential diagnosis cut-off point, and then calculate the sensitivity, specificity, accuracy, positive predictive value and negative predictive value respectively.(5)Compare the sensitivity, specificity and accuracy of SUVearly, SUVdelayed and Δ SUV respectively, and find the best method to differentiate malignant from benign colorectal diseases.(6)Statistical method:using SPSS statistical software17.0for data analysis.Results:(1)The SUVearly, SUVdelayed and ΔSUV of the malignant disease were all significant higher than the benign one.(2)Of the malignant disease, the SUVdelayed were significant higher than SUVearly, while there were no significant difference between SUVearly and SUVdelayed in the benign disease.(3) The best differential diagnosis cut-off point of SUVearly, SUVdelayed and ΔSUV were8.7.10.9and13.4%respectively. Took the SUVearly of more than8.7as positive diagnostic criteria, the sensitivity was81.8%, the specificity was71.4%, the accuracy was79.3%, the positive predictive value was90.0%, and the negative predictive value was55.6%. Took the SUVdelayed of more than10.9as positive diagnostic criteria, the sensitivity was84.1%, the specificity was78.6%. the accuracy was82.8%, the positive predictive value was92.5%, and the negative predictive value was61.1%. Took the ΔSUV of more than13.4%as positive diagnostic criteria, the sensitivity was95.5%, the specificity was100.0%, the accuracy was96.6%, the positive predictive value was100.0%, and the negative predictive value was87.5%.(4)There were all no significant difference of sensitivity, specificity and accuracy between SUVearly and SUVdelayed. The sensitivity and accuracy of ΔSUV were all significant higher than SUVearly, while there were no significant difference of specificity between SUVearly and ΔSUV. The accuracy of ΔSUV were significant higher than SUVdelayed, while there were all no significant difference of sensitivity and specificity between SUVdelayed and ΔSUV.Conclusions:(1)There were all significant difference of the SUVearly, SUVdelayed and ΔSUV between the malignant disease and the benign one. The SUVearly, SUVdelayed and ΔSUV can be used for differentiating malignant from benign colorectal diseases.(2)There were significant difference between the SUVearly and SUVdelayed in the malignant disease, while there were no significant difference between the SUVearly and SUVdelayed in the benign disease. The change of the SUVearly and SUVdelayed can be used for differentiating malignant from benign colorectal diseases.(3)The best differential diagnosis cut-off point of SUVearly. SUVdelayed and ΔSUV were8.7,10.9and13.4%respectively. Took them as positive diagnostic criteria, the sensitivity and specificity were the highest.(4)The accuracy of dual-time-point18F-FDG PET/CT imaging was significant higher than the single-time-point18F-FDG PET/CT imaging. The dual-time-point18F-FDG PET/CT imaging was better than the single-time-point18F-FDG PET/CT imaging in differentiation of malignant from benign colorectal diseases, but it can’t take place the histopathological examination.