Comparative evaluation of Tc-99m-heat-denatured RBC and Tc-99m-anti-D IgG opsonized RBC spleen planar and SPECT scintigraphy in the detection of accessory spleen in postsplenectomy patients with chronic idiopathic thrombocytopenic purpura.

OBJECTIVE: Radionuclide imaging specific for functioning splenic tissue is considered the method of choice to detect an accessory spleen in patients of chronic idiopathic thrombocytopenia purpura (ITP), who present with relapse after splenectomy. Radioimmunospleen scintigraphy with Tc-99m-labeled autologous RBC opsonized with anti-D IgG (RIS) is claimed to be more sensitive and specific than Tc-99m heat-denatured RBC spleen scintigraphy (HDRS) in the detection of an accessory spleen. We compared the efficacy of RIS with HDRBC for the detection of accessory spleens

METHODS: A total of 45 patients (male:female = 17:28, age range: 6-58 years) who presented with relapse of ITP after splenectomy underwent scintigraphy with both methods. An average of 3 years had passed since surgery. All patients were imaged by a dual-head gamma camera with high-resolution collimators; planar static images and SPECT of abdomen were acquired.

RESULTS: Accessory spleens were detected in 31% (14 of 45) of patients, 6 had 1 each and 8 had more than 1 (including 1 patient who had 13 accessory spleens). Both methods were concordant in all the patients. There was no difference in the scintigraphic picture (planar and SPECT) or in the size and number of accessory spleens detected.

CONCLUSION: Tc-99m-labeled anti-D IgG opsonized autologous RBC spleen scintigraphy provides no additional diagnostic information over heat-denatured RBC spleen scintigraphy. Heat-denatured RBC scintigraphy thus remains the procedure of choice in the detection of accessory spleens.