Whole-body gallium 67 scans. Role in diagnosis of sarcoidosis

Early studies of 67gallium (67Ga) scanning in sarcoidosis focused on the lungs as a measure of disease activity, likelihood of progression, and the advisability of corticosteroid therapy. The predictive value of pulmonary uptake proved to be limited, but there has been renewed interest in 67Ga scanning as a diagnostic aid with special attention to characteristic extrapulmonary uptake patterns. Review of whole-body 67Ga scans in 172 patients with sarcoidosis, 21 with lymphoma, and 51 with other disorders demonstrated distinctive cranial, mediastinal, and hilar uptake patterns in sarcoidosis patients. Bilateral hilar uptake occurred in 81 sarcoidosis patients (47%) but in no lymphoma cases. Increased lacrimal and/or salivary gland uptake was observed in 47.5% but lacked specificity. Uptake in peripheral lymph nodes was infrequent in sarcoidosis (5%) but common in lymphoma (57%). 67Ga scans are especially valuable in patients with uveitis and liver granulomas whose chest radiographs are normal or equivocal. 67Ga scans, unnecessary in typical cases of sarcoidosis, have an important diagnostic role by reducing the need for invasive biopsy procedures in asymptomatic patients.