Gallium-67 in the evaluation of sarcoidosis: correlations with serum angiotensin-converting enzyme and bronchoalveolar lavage.

Gallium-67 (67Ga) scanning was assessed for its usefulness in the evaluation and follow-up of 54 patients with sarcoidosis, both treated and untreated. Scans were repeated in 23 subjects. Serum levels of angiotensin-converting enzyme (ACE) were determined concurrently in all 54 patients and bronchoalveolar lavage was performed in 29 patients. Gallium-67 scan was effective in the detection and assessment of lesions not revealed by traditional methods of investigation, particularly those affecting the mediastinum, spleen, and salivary glands. The scan also enabled fibrotic lesions, which do not show uptake, to be distinguished from granulomatous lesions, which do--an advantage of prognostic interest particularly in patients with pulmonary lesions. Another merit of 67Ga scanning was that it offered a means of following disease progression in each site. In patients showing spontaneous clearing of disease or receiving treatment the scintigraphic method was more sensitive than serum ACE determination. Scan findings showed a rough correlation with serum ACE but not with bronchoalveolar lavage findings. This suggests that the three markers probably reflect different stages of the granulomatous process. On the strength of this study the indications for gallium scanning in sarcoid patients can be defined more clearly than has previously been possible.