Whole-body Gallium 67 Scans: Role in Diagnosis of Sarcoidosis

Abstract

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.

Hepatic and splenic sarcoidosis: Ultrasound and MR imaging

“…Less commonly involved organs include skin, eyes, muscle, genitalia, and subdiaphragmatic organs [1][2]. Involvement of abdominal lymph nodes, liver and spleen, gastrointestinal tract, kidneys, and pancreas have been noted on barium studies [3], ultrasound [4][5], CT [5][6][7][8][9][10], MRI [11-121, and scintigraphy [14,15]. Although sarcoid granulomas are usually only 100-200/xm in size [16], bulky mass-like granulomatous tissue can mimic malignancy [4,5].…”

“…Technetium 99 m scan can show normal spleen, nonspecific splenomegaly, heterogeneous uptake, or photon-deficient focal areas [ 14]. In one series, gallium 67 scan detected increased splenic intake in 4% of patients with sarcoidosis [15].…”

Imaging the inflammatory activity of sarcoidosis

“…The panda sign is based on the symmetrical activity in the lacrimal and parotid glands. However, these signs have demonstrated a poor diagnostic sensitivity in biopsy-proven sarcoidosis patients [28][29][30]. Furthermore, the panda sign can also be found in patients with HIV, malignant lymphomas and Sjö gren's syndrome.…”

Use of PET-CT for the assessment of treatment results in patients with sarcoidosis

“…However, this technique has limited sensitivity and specificity. Whole-body [ 18 F] fluorodeoxyglucose positron emission tomographycomputed tomography (FDG PET-CT) is more sensitive than gallium-67 and is currently used to determine the extent of inflammation in patients with sarcoidosis [2][3][4][5][6][7][8]. PET-CT uptake values are presented as standard uptake values (SUV or SUVmax) [9].…”