• 99mTc-HMPAO-WBC
• cardiac implantable electronic device
• infectious endocarditis

Clinical performance of the Duke Endocarditis Service criteria to establish the diagnosis of infectious endocarditis (IE) and cardiac implantable electronic device (CIED) infection can be improved through functional imaging procedures such as radiolabeled leukocytes (99mTc-HMPAO-WBC). Methods: We assessed the value of 99mTc-HMPAO-WBC scintigraphy including SPECT/CT acquisitions in two series of 131 and 56 consecutive patients with suspected IE and CIED, respectively. 99mTc-HMPAO-WBC scintigraphy results were correlated with transthoracic (TTE) or transesophageal (TEE) echocardiography, blood culture and the Duke criteria. Results: The scan was particularly valuable in patients with negative and/or difficult-to-interpret echocardiographic findings. Conclusions: Our results demonstrate 99mTc-HMPAO-WBC scintigraphy ability to reduce the rate of misdiagnosed IE when combined to the standard diagnostic tests (a) in patients with high clinical suspicion but inconclusive echocardiographic findings; (b) for the differential diagnosis between septic and sterile vegetations detected at echocardiography; (c) when echocardiographic, laboratory and clinical data are contradictory, as also to exclude valve involvement (especially of a prosthetic valve) during febrile episodes, sepsis or post-surgical infections.