A single photon emission computed tomography of the chest with the use of receptor radiotracer (Tc-99m-Depreotide) in sarcoidosis

BACKGROUND Sarcoidosis is a systemic and multiorgan disease with unknown etiopathogenesis. Granulomas that do not undergo necrosis and caseous degeneration are distinctive for this disease. Mostly it is connected with young adults, more frequently females than males, and changes are mainly situated in the lymph nodes of the pulmonary hilus and pulmonary parenchyma. Somatotropin release inhibiting hormone receptors could be located in epithelioid and giant cells that create sarcoidal tubercles and lymph nodes. Aim of the study was to determine the usefulness of a single photon emission tomography (SPECT) for an evaluation of the range of sarcoidal changes in the chest after using a receptor tracer. An assumption was made that scintigraphy with the use of Tc-99m-Depreotide could help with location of extrapulmonary sarcoidosis focuses. MATERIAL/METHODS Authors present five patients with clinically recognized and histopathologically confirmed sarcoidosis. Patients were given Tc-99m-Depreotide and underwent SPECT of chest. The results were compared with X-rays of these patients chests and with the accumulation of radiotracer in 2 other patients with carcinoid syndrome without visible pathological changes in examination. Patients got an intravenous injection of 500 MBq (14mCi) Tc-99m-Depreotide. SPECT of chest together with a "whole body" examination, was performed after 2 hours and 24 hours. RESULTS Higher radiotracer accumulation was observed in all patients in the area of some chest lymph nodes, in pulmonary tissue in 3 patients and in other groups of lymph nodes in 2 patients. CONCLUSIONS Emission Tomography of the chest with the use of receptor radiotracer (Tc-99m-Depreotide) can be a crucial complement of sarcoidosis diagnostics in an evaluation of the extent of lung changes together with an estimation of chest lymph nodes abnormalities.