SPECT/CT with 99mTc-EDDA-HYNIC-TOC and 111In-DTPA-octreotide for evaluation of systemic granulomatous infections

1974 Objectives To evaluate the usefulness of SPECT/CT with radiolabeled somatostatin analogs (RSA) for the evaluation of patients with systemic granulomatous infections in comparison with gallium-67 citrate scintigraphy. Methods Fourteen consecutive patients (10 female, 18 to 76 years-old, mean age: 41,4 ± 16.9 years) with active systemic granulomatous infections were studied, including: tuberculosis (6), paracoccidioidomycosis (4), pneumocystis (2), leishmaniasis (1) and infectious vasculites (1). Twelve/14 patients had already started specific treatment for the diverse infectious diseases 8 ± 4 days before the study. All patients were submitted to whole-body and SPECT/CT imaging, 7 of them 4 hours after the injection of 300 MBq of 99mTc-EDDA-HYNIC-TOC and the same was done to the other 7 patients 24 hours after the injection of 185 MBq of 111In-DTPA-octreotide. All patients were also submitted to the same imaging protocol 48h after the injection of 185 MBq of gallium-67 citrate. The maximum time interval between the two procedures was one week. Tracer uptake was visually classified as mild, moderate or marked. Results Eleven sites of focal or diffuse active infectious disease were detected by 67Ga in 9 of 14 patients. All those sites were also detected by RSA images. The images of both tracers were negative in the other 5 of 14 patients. The intensity of 67Ga uptake was visually higher than RSA uptake in 7 of the 9 patients with positive images, possibly due to previous treatment. The intensities of 99mTc-EDDA-HYNIC-TOC and 111In-DTPA-octreotide uptake in the lesions were similar when compared to 67Ga uptake. Conclusions SPECT/CT with 99mTc-EDDA-HYNIC-TOC and 111In-DTPA-octreotide seem to be good options for the evaluation of patients with systemic granulomatous infections when compared to 67Ga.