Application of 11C-CHO and 18F-FDG dual-phase PET/CT imaging combined with high-resolution computed tomography in differential diagnosis of solitary pulmonary nodules

Abstract

Objective To compare choline (11C-CHO) PET/CT, conventional 18F-FDG PET/CT, 18F-FDG double-phase PET/CT, and 11C-CHO PET/CT+18F-FDG double-phase PET/CT imaging combined with high-resolution computed tomography(HRCT) to determine whether differential diagnosis value for solitary pulmonary nodules (SPN) is benign or malignant. Methods This study included 28 patients who were clinically diagnosed with SPN. Patients were injected with 18F-FDG then subjected to PET/CT scan after 1 and 2 h and were injected with 11C-CHO then subjected to PET/CT scan again after 10 min. PET images were analyzed by SPN maximum section ROI and SUVmax as a semi-quantitative index, wherein values higher than 2.5 are considered positive for SPN. SUVmax in routine were compared with that in delayed 18F-FDG PET/CT imaging, wherein an increase of more than 10% indicates malignant lesions (positive), whereas a decrease or increase by less than 10% indicates benign lesions (negative). Benign or malignant lesion were analyzed with lobulation, short spiculation and pleural tail sign, air bronchogram, vascular convergence sign, and vacuole sign in HRCT imaging. All cases were analyzed and clinically followed-up. Imaging diagnoses were compared with pathological results or clinical follow-up. SUVmax comparisons between groups were tested by t-test and the enumeration data were compared by analysis of variance. Results Twenty-eight patients were pathologically diagnosed and clinically followed-up. Seventeen patients were diagnosed with lung cancer, seven with tuberculosis, and four with sarcoidosis. Twenty patients were confirmed by routine 18F-FDG PET/CT imaging, 24 by double-phase 18F-FDG PET/CT imaging, 23 by routine 11C-CHO PET/CT imaging, and 27 by 11C-CHO PET/CT+ 18F-FDG double-phase PET/CT+ HRCT. 18F-FDG and 11C-CHO SUVmax in benign or malignant nodules in 28 patients were analyzed. Differences were statistically significant(t=10.57 and 13.19, both P<0.05). A significant difference exists between benign and malignant nodules in the leaf, burr, pleural tail sign, and vascular bundle sign(χ2=9.27, 10.36, 14.31, and 17.52, all P<0.05). The sensitivity, specificity and accuracy of 11C-CHO+18F-FDG dual phase PET/CT+HRCT were 90.0%, 91.7% and 96.4%, significantly higher than that of the others uncombined imaging. Conclusion 11C-CHO PET/CT+ 18F-FDG dual-phase PET/CT+HRCT can determine whether SPN is benign or malignant. Combine the three scan models will improve diagnostic efficiency of SPN. Key words: Solitary pulmonary nodules; Choline; Fluorodeoxyglucose F18; Positron-emission to-mography; Tomography, X-ray computed