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 (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 Tc-EDDA-HYNIC-TOC, and 21 after injection of In-DTPA-octreotide. All patients also underwent Ga citrate imaging, except for one patient who died before the Ga was available.

Results: In 20 of the 27 patients who underwent imaging with both tracers, 27 sites of active disease were detected by 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 Ga uptake in 11 of the 20 patients with positive images and similar to Ga uptake in the other 9 patients. The only patient who did not undergo Ga scintigraphy underwent 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 Tc-EDDA-HYNIC-TOC or In-DTPA-octreotide seems to be a good alternative to Ga citrate imaging for the evaluation of patients with systemic granulomatous disease.