99mTc-HMPAO-Labeled Autologous Leukocyte SPECT/CT for Diagnosis of Bacterial Endocarditis of the Prosthetic Pulmonary Conduit: A Clinical Case

In this paper, we present a case of bacterial endocarditis of the prosthetic pulmonary conduit found in a 26-year-old man. An echocardiography study around the pulmonary valve showed the presence of a floating mass attached to the wall of the conduit. This formation was thought to be a floating calcific leaflet of the conduit or a developed vegetation of the conduit. Due to the uncertainty of the results, pulmonary multidetector row computed tomography (MDCT) angiography was performed. The MDCT examination showed the presence of a floating 4 × 8-mm sized mass in the pulmonary conduit. Taking into account the patient’s complaints, medical history data, and clinical-instrumental examination, myocardial scintigraphy with 99mTc-HMPAO-labelled autologous leukocytes combined with CT (99mTc-HMPAO-SPECT/CT) was performed. Based on overlaying of the scintigraphic images and the MDCT aortography scans, anatomic localization of the pathologic accumulation was found in a projection of the pulmonary valve prosthesis. Surgical intervention, with cardiopulmonary bypass, was performed for replacement of the valve-containing conduit. Pathomorphologic study of the surgical material confirmed the hypothesis of bacterial endocarditis. Therefore, hybrid technologies such as 99mTc-HMPAO-SPECT/CT contribute to the earlier and more precise diagnosis of infectious endocarditis, avoiding many errors associated with patient treatment and the development of complications.