Nuclear medicine imaging of endocarditis

Area of Science:

• Cardiology
• Nuclear Medicine
• Medical Imaging

Background:

• Infective endocarditis (IE) is a severe condition necessitating prompt diagnosis and treatment.
• Echocardiography is crucial for IE diagnosis and monitoring but struggles with subtle subacute cases and differentiating vegetations from post-treatment changes.
• Existing scintigraphy methods like Gallium-67 and Indium-111 labelled leukocytes have shown limitations in sensitivity and diagnostic value for IE.

Purpose of the Study:

• To evaluate scintigraphy as a complementary diagnostic tool for infective endocarditis, particularly subacute cases.
• To assess the utility of SPECT immunoscintigraphy with 99mTc labelled antigranulocyte antibodies in IE diagnosis and follow-up.
• To determine if combined imaging modalities improve diagnostic accuracy for infective endocarditis.

Main Methods:

• Investigated various scintigraphy techniques including Gallium-67, Indium-111 labelled leukocytes, and 99mTc labelled antigranulocyte antibodies.
• Employed SPECT (Single Photon Emission Computed Tomography) imaging for enhanced detection of cardiac valve abnormalities.
• Compared the diagnostic performance of scintigraphy, particularly SPECT immunoscintigraphy, with echocardiography in infective endocarditis patients.

Main Results:

• Gallium-67 scintigraphy results are not yet convincing, though modern techniques may improve outcomes.
• Indium-111 labelled leukocytes showed unacceptably low sensitivity for IE detection.
• SPECT immunoscintigraphy with 99mTc labelled antigranulocyte antibodies complements echocardiography, assessing inflammatory activity and improving detection of subacute IE, especially in difficult cases.

Conclusions:

• Combined use of echocardiography and SPECT immunoscintigraphy enables detection of nearly all subacute infective endocarditis cases.
• SPECT immunoscintigraphy is valuable for diagnosing ambiguous IE cases, particularly when echocardiography is inconclusive or pre-existing valve disease is present.
• This imaging approach aids in follow-up and monitoring the effectiveness of antibiotic therapy for infective endocarditis.