Evaluation of pulmonary lesions with FDG-PET. Comparison of findings in patients with and without a history of prior malignancy

Chest. 1996 Apr;109(4):982-8. doi: 10.1378/chest.109.4.982.


Study objective: The purpose of this study was to evaluate the accuracy of positron emission tomography (PET) using F-18 fluorodeoxyglucose (FDG) in differentiating benign from malignant pulmonary lesions both in patients with and without a history of prior malignancy.

Design: Forty-eight consecutive patients with pulmonary lesions suspicious for malignancy underwent FDG-PET scanning. Group 1 included 27 patients without and group 2 included 21 patients with a history of malignancy. Pathologic proof of diagnosis was obtained for 32 patients and 16 patients were followed up clinically and radiographically for at least 6 month. The standard uptake ratio (SUR) and the lesion to background (L/B) ratio were determined in 45 patients.

Setting: Vanderbilt University Medical Center.

Results: In group 1, the average SUR and L/B ratio for malignant lesions (n=14) were 8.9 +/- 4.9 and 20.6 +/- 14.2, respectively. For benign lesions (n=12), the average SUR was 3.3 +/- 3.2 and L/B ratio was 5.2 +/- 5.5. In group 2, the average SUR and L/B ratio for malignant lesions were not significantly different from group 1. Using either a SUR greater than 2.5 or L/B ratio greater than 5 as an cutoff level to differentiate benign and malignant lesions, the sensitivity and negative predictive value in both groups were 100%. There were five false-positive studies in group 1 and one in group 2, including tuberculosis (n=2), a granulomatous lesion (n=1), an inflammatory lesion (n=1), a schwannoma (n=1), and a fibrous mesothelioma (n=1). The overall accuracy was 88%, 81% in group 1, and 95% in group 2.

Conclusion: FDG-PET can identify malignant pulmonary lesions both in patients without and with a history of prior malignancy with a high sensitivity and negative predictive value for lesions greater than 1 cm (100% in this study). High FDG uptake by some inflammatory processes and benign tumors may cause false-positive results. Semiquantitative evaluation using SUR or L/B ratio provides similar accuracy.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Deoxyglucose / analogs & derivatives*
  • False Positive Reactions
  • Female
  • Fluorine Radioisotopes*
  • Fluorodeoxyglucose F18
  • Follow-Up Studies
  • Granuloma / diagnostic imaging
  • Humans
  • Lung Diseases / diagnostic imaging*
  • Lung Diseases / pathology
  • Lung Neoplasms / diagnostic imaging*
  • Lung Neoplasms / pathology
  • Male
  • Mesothelioma / diagnostic imaging
  • Middle Aged
  • Neurilemmoma / diagnostic imaging
  • Pneumonia / diagnostic imaging
  • Predictive Value of Tests
  • Radiography
  • Radionuclide Imaging
  • Sensitivity and Specificity
  • Tuberculosis, Pulmonary / diagnostic imaging


  • Fluorine Radioisotopes
  • Fluorodeoxyglucose F18
  • Deoxyglucose