SPECT/CT with radiolabeled somatostatin analogues in the evaluation of systemic granulomatous infections

OBJECTIVE: To evaluate SPECT/CT with radiolabeled somatostatin analogues (RSAs) in systemic granulomatous infections in comparison with gallium-67 ((67)Ga) citrate scintigraphy. MATERIALS AND METHODS: We studied 28 patients with active systemic granulomatous infections, including tuberculosis, paracoccidioidomycosis, pneumocystosis, cryptococcosis, aspergillosis, leishmaniasis, infectious vasculitis, and an unspecified opportunistic infection. Of the 28 patients, 23 had started specific treatment before the study outset. All patients underwent whole-body SPECT/CT imaging: 7 after injection of (99m)Tc-EDDA-HYNIC-TOC, and 21 after injection of (111)In-DTPA-octreotide. All patients also underwent (67)Ga citrate imaging, except for one patient who died before the (67)Ga was available. RESULTS: In 20 of the 27 patients who underwent imaging with both tracers, 27 sites of active disease were detected by (67)Ga citrate imaging and by SPECT/CT with an RSA. Both tracers had negative results in the other 7 patients. RSA uptake was visually lower than (67)Ga uptake in 11 of the 20 patients with positive images and similar to (67)Ga uptake in the other 9 patients. The only patient who did not undergo (67)Ga scintigraphy underwent (99m)Tc-EDDA-HYNIC-TOC SPECT/CT-guided biopsy of a lung cavity with focal RSA uptake, which turned to be positive for aspergillosis. CONCLUSION: SPECT/CT with (99m)Tc-EDDA-HYNIC-TOC or (111)In-DTPA-octreotide seems to be a good alternative to (67)Ga citrate imaging for the evaluation of patients with systemic granulomatous disease.