关键词: 双时相, ¹⁸F-FDG, 符合线路, SPECT/CT, 肺癌, 鉴别诊断

Abstract: Background and purpose: Although FDG tumor imaging has been applied in clinic widely, dual-phase imaging can provide much more information about the FDG uptaking of pulmonary lesions. The purpose of the study was to evaluate the usefulness of dual-phase ¹⁸F-FDG coincidence detection SPECT/CT imaging in the differential diagnosis of the pulmonary lesions. Methods: There were 28 patients with pulmonary lesions which were detected by CT. All the patients undertook the SPECT/CT imaging at 2 time-phases respectively: early imaging at 40-60 min and delayed imaging at 2-3 h after the intravenous injection of FDG. Data processing: calculating the radio of T and N in early and delayed imaging respectively; T: The radioactive count of the lesions; N: The radioactive count of the normal tissue; and the change rate: ΔT/N. ROC was used to find out the threshold of T₁/N₁, T₂/N₂及ΔT/N in the differential diagnosis between benign and malignant lesions. AUC was used to evaluate the diagnosis value of the dual-phase and single-phase imaging. Results: The threshold of T1/N1 in early imaging was 2.65, whereas AUC was 0.767. The sensitivity, specificity and accuracy were 83.3%, 30% and 64.3%, respectively. The threshold of T₂/N₂ in delayed imaging was 3.14, whereas AUC was 0.847. The sensitivity, specificity and accuracy were 94.4%, 60.0% and 82.1%, respectively. The threshold of ΔT/N in delayed imaging was 16.9%, whereas AUC is 0.950. The sensitivity, specificity and accuracy were 88.5%, 71.4% and 86.2%, respectively. Conclusion: Dual-phase ¹⁸F-FDG coincidence detection SPECT/CT imaging has much higher accuracy and specificity. However it still has false positivity, and should be analyzed with CT and clinical history.

Key words: Dual phase, ¹⁸F-FDG, Coincidence Detection, SPECT/CT, Lung cancer, Differential diagnosis