Nuclear medicine imaging of endocarditis

Infective endocarditis is a serious disease which requires early diagnosis and adequate therapy. Echocardiography plays a key role in diagnosis and fo llow-up. Subacute infective endocarditis, however, is often difficult to pr ove echocardiographically due to its more subtle morphological changes. Als o, echocardiography cannot reliably differentiate florid vegetations from r esidual structural changes of the affected valves in cured patients. Theref ore, scintigraphy of infection and inflammation, a functional imaging proce dure, has been investigated as a complementary tool in diagnosis and follow -up of infective endocarditis, So far, results obtained with Gallium-67 sci ntigraphy are not convincing, although an improvement by using modern acqui sition techniques seems possible. Scintigraphy with Indium-lll labelled leu kocytes has an unacceptably low sensitivity, which is probably due to the s mall number of cells involved and unfavourable imaging characteristics of I n-111-Technetium-99m labelled leukocytes have been investigated in few pati ents, so final judgement is not yet possible. SPECT imaging might enhance t he detectability of diseased heart valves. Immunoscintigraphy with the Tc-9 9m labelled antigranulocyte antibody in SPECT technique is complementary to echocardiography and seems to assess the floridity of the underlying infla mmatory process. The combined use of both imaging modalities allows detecti on of virtually all cases of subacute infective endocarditis. SPECT immunos cintigraphy with the antigranulocyte antibody seems useful in doubtful case s of infective endocarditis, especially, if echocardiography is nondiagnost ic and valve pathology pre-existing. The method may be used for follow-up a nd monitoring antibiotic therapy.