Probability of malignancy in solitary pulmonary nodules using fluorine-18-FDG and PET.

UNLABELLED: Nearly one-third of solitary pulmonary nodules are radiographically indeterminate for the presence of malignancy.

METHODS: FDG-PET imaging was used to differentiate benign and malignant solitary pulmonary nodules in 61 patients with radiographically indeterminate nodules. After confirmation of the histological diagnosis, the probability for cancer was established for positive and negative PET scans and compared to the risk estimates calculated using other patient variables.

RESULTS: FDG-PET had a sensitivity, specificity and positive predictive value of 93%, 88% and 92%, respectively, for detecting malignancy in indeterminate solitary pulmonary nodules. The probability of malignancy with a positive PET scan is 83%, which increases with the patient's age (90% in >60 yr) and the size of the nodule. A negative PET scan is associated with only a 4.7% risk of malignancy. FDG-PET also accurately characterized hilar/mediastinal lymphadenopathy in 12 patients with associated lymph node lesions.

CONCLUSION: FDG-PET imaging can be a useful noninvasive test to determine the risk estimate or probability of cancer as well as preoperative staging in patients with radiographically indeterminate solitary pulmonary nodules.