Incremental Value of Integrated FDG PET/CT in Evaluating Indeterminate Solitary Pulmonary Nodule for Malignancy

  • Dr Chih-Yung Chang, Department of Nuclear Medicine, Tri-Service General Hospital, Taipei, Taiwan, Taiwan
  • Dr Ching Tzao, Department of Thoracic Surgery, Tri-Service General Hospital, Taipei, Taiwan, Taiwan
  • Dr Shih-chun Lee, Department of Thoracic Surgery, Tri-Service General Hospital, Taipei, Taiwan, Taiwan
  • Dr Cheng-Yi Cheng, Department of Nuclear Medicine, Tri-Service General Hospital, Taipei, Taiwan, Taiwan
  • Dr Chang-Hsien Liou, Department of Radiology, Tri-Service General Hospital, Taipei, Taiwan, Taiwan
  • Dr Wen-Sheng Huang, Department of Nuclear Medicine, Tri-service General Hospital, Taipei, Taiwan, Taiwan
  • Dr Ching-yee Wong, Department of Nuclear Medicine, William Beaumont Hospital, Royal Oak, Michigan, USA, United States

    • Objectives: To evaluate the incremental diagnostic value of integrated interpretation of PET/CT in evaluating solitary pulmonary nodules for malignancy.

    Methods: A total of 117 patients (67 male and 50 female, mean age±SD: 61.7±13.6 years, range: 31-86 years) with indeterminate solitary pulmonary nodules and without previous history of malignancy were analyzed. The PET/CT was performed 1 hr after a 370 MBq 18F-FDG intravenous injection using an integrated PET/CT scanner (Siemens Biograph BGO duo). Patients fasted 6 hr prior the imaging. PET was interpreted alone or combined with CT and was graded with the described 5-point scale. Malignant diagnosis was based on histological findings or a clinical and radiological follow-up of at least 24 months. Diagnostic performance of PET alone and integrated criteria were performed using a discriminant analysis.

    Results: PET alone classified correctly 85% and the integrated criteria increased the correct classification to 89% yet comparable sensitivity and specificity of 88% and 89% respectively. False positive PET results were mainly from granulomatous disorders. Four out of 8 PET indeterminate cases by PET alone were resolved (50%) when combined with the CT interpretation.

    Conclusions: While additional gain of integrated PET/CT from the CT part was limited, PET and CT are synergistic and significantly increment of diagnostic value in PET indeterminate cases.