My Approach To Nuclear Medicine in the Evaluation of Prosthetic Valve and Cardiac Implantable Electronic Device Endocarditis

Summary

Nuclear medicine has played an increasing role in the evaluation of patients with a suspected or confirmed diagnosis of infective endocarditis. Scintigraphy with marked leukocytes (ML) is a method widely used in clinical practice to detect sites of infection, being especially indicated in patients with suspected infective endocarditis (IE) in prosthetic valves or implantable cardiac devices (ICD) when other conventional imaging methods studies are not conclusive. The technique involves labeling the patient’s own leukocytes with a radiotracer, such as 99m Tc-HMPAO, maintaining its biological properties. Upon injection into the bloodstream, leukocytes actively mark sites of active inflammation, allowing detection of infection.

Blood collection for ML scintigraphy requires a sufficient amount of leukocytes, which can be a major limiting factor in patients with neutropenia. Another point of limitation is that the leukocyte labeling process and the start of obtaining scintigraphic images can take about 2 hours. The images are acquired at different times, and the presence of capture in the 4-hour and 24-hour images is important to confirm the presence of active infection.

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