Background: To study the role of whole-body 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) scans in the identification of occult biopsy sites and reversible granulomatous disease in patients with sarcoidosis.
Methods: A retrospective review was undertaken of 188 FDG PET scans performed in 137 patients with proven sarcoidosis. All patients had given a complete medical history and undergone a physical examination, standard chest radiograph, spirometry, diffusing capacity determination, and measurement of serum angiotensin-converting enzymes levels.
Results: One hundred thirty-nine whole-body scans had positive findings. The most common positive sites were mediastinal lymph nodes (54 scans), extrathoracic lymph nodes (30 scans), and lung (24 scans). The standardized uptake value (SUV) ranged from 2.0 to 15.8. Twenty occult disease sites were identified. Eleven repeat scans exhibited decreased SUV with corticosteroid therapy. The positive pulmonary FDG PET scan findings occurred in two thirds of patients with radiographic stage II and III sarcoidosis. Negative pulmonary FDG PET scan findings were common in patients with radiographic stage 0, I, and IV sarcoidosis.
Conclusions: Whole-body FDG PET scans are of value in identifying occult and reversible granulomas in patients with sarcoidosis. However, a positive FDG PET scan finding, by itself, is not an indication for treatment.