Incremental value of integrated FDG-PET/CT in evaluating indeterminate solitary pulmonary nodule for malignancy.
Chih-Yung Chang, Ching Tzao, Shih-Chun Lee, Cheng-Yi Cheng, Chang-Hsien Liu, Wen-Sheng Huang, Chih-Hung Ku, Jong-Kang Lee, Ching-Yee Oliver Wong
Author Information
Chih-Yung Chang: Department of Nuclear Medicine, Tri-Service General Hospital, National Defense Medical Center, 325 Section 2 Cheng-Kung Road, Taipei, Taiwan.
OBJECTIVES: The objective of this study was to evaluate the increased diagnostic benefit of integrated positron emission tomography/computed tomography (PET/CT) interpretation in evaluating solitary pulmonary nodules for malignancy. METHODS: One hundred seventeen patients (67 men and 50 women; mean age +/- SD, 61.7 +/- 13.6 years, range, 31-86 years) with indeterminate solitary pulmonary nodules and no previous history of malignancy were analyzed. PET/CT was performed with an integrated PET/CT scanner (Siemens Biograph BGO duo) 1 h after an intravenous injection of 370 MBq (10 mCi) (18)F-fluorodeoxyglucose. Patients fasted for 6 h before imaging. PET was interpreted alone or combined with CT and was graded according to a five-point scale. A malignant diagnosis was based on histological findings or a clinical and radiological follow-up after at least 24 months. The diagnostic performances of PET alone and integrated PET/CT interpretation were evaluated using discriminant analysis. RESULTS: PET alone correctly classified 85% of nodules and integrated PET/CT interpretation increased the correct classification to 89%, with similar sensitivity and specificity of 88% and 89%, respectively. False-positive PET results mainly resulted from granulomatous disorders. Four (50%) of the eight cases deemed indeterminate on PET alone were resolved with combined PET/CT interpretation. CONCLUSIONS: Although the benefit attributable to the CT component was limited when integrated PET/CT was used, PET and CT acted synergistically to significantly increase the diagnostic veracity for PET-indeterminate nodules.
