Role of PET/CT in Detecting Infective Endocarditis
Yes, infective endocarditis can be detected on PET/CT scans, particularly in cases involving prosthetic valves or cardiac implantable electronic devices, but it has limited sensitivity for native valve endocarditis. 1
Diagnostic Performance of PET/CT in Infective Endocarditis
Prosthetic Valve Endocarditis (PVE)
- FDG-PET/CT demonstrates high diagnostic value for prosthetic valve endocarditis with sensitivity ranging from 73% to 100% and specificity of 71% to 100% 1
- Adding FDG-PET/CT findings as an additional major criterion to the modified Duke Criteria significantly increases diagnostic sensitivity from 52-70% to 91-97% without compromising specificity 1
- FDG-PET/CT can detect peri-prosthetic abscesses in cases where transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) were normal or equivocal 1
- PET/CT can diagnose PVE earlier than TEE and CT angiography before anatomical damage occurs and even earlier than surgical exploration 1
Native Valve Endocarditis (NVE)
- FDG-PET/CT has poor sensitivity (as low as 22%) for native valve endocarditis, limiting its utility in these cases 2
- One retrospective study showed 0% sensitivity for diagnosing native valve endocarditis when compared with the modified Duke criteria 1
- Absence of intracardiac lesions on FDG-PET/CT cannot rule out native valve endocarditis 3
Cardiac Implantable Electronic Device (CIED) Infections
- For CIED infection evaluation, FDG-PET/CT has a pooled sensitivity and specificity of 87% and 94%, respectively 1
- PET/CT shows high sensitivity for pocket infections but lower sensitivity for lead infections 3
- Several single-center studies have demonstrated promising results in identifying CIED infections using FDG-PET/CT with sensitivities ranging from 60% to 100% and specificities from 86% to 100% 1
Additional Benefits of PET/CT in Infective Endocarditis
- FDG-PET/CT can detect clinically unsuspected sites of extracardiac infection in up to 24% of cases 1
- As a whole-body scan, PET/CT can identify unexpected infectious foci outside the heart/chest that may change clinical management 1
- Can detect septic emboli, which is critical for patient management, especially in prosthetic valve endocarditis 1
Limitations and Technical Considerations
- Differentiation between device infection and nonspecific inflammation can be achieved based on FDG uptake pattern: focal in infection versus homogeneous in inflammation 1
- False negatives may occur if PET/CT is performed after antibiotic therapy (≥48 hours) has been initiated 4
- Patient preparation and image interpretation methods significantly affect diagnostic accuracy 5
- Abnormal FDG uptake seen on attenuation-corrected PET images should be confirmed on non-attenuation-corrected PET images to avoid potential artifacts from metallic devices 1
Comparison with Other Imaging Modalities
- Echocardiography (TTE and TEE) remains the first-line imaging test in suspected endocarditis 1
- When echocardiography is inconclusive in suspected prosthetic valve endocarditis, white blood cell (WBC) scans have lower sensitivity (64%) but higher specificity (100%) compared to FDG-PET/CT (sensitivity 93%, specificity 71%) 6
- CT may be superior to echocardiography in detecting and visualizing the full extent of paravalvular abscess, pseudoaneurysm, or fistula, particularly in patients with prosthetic valves 1
Clinical Recommendations
- For suspected prosthetic valve endocarditis or CIED infections, FDG-PET/CT should be considered when echocardiography results are inconclusive 1
- FDG-PET/CT is particularly valuable for cases classified as "possible" endocarditis by the modified Duke criteria, helping to reclassify them as "definite" diagnosis 1
- For native valve endocarditis, PET/CT should only be considered as a complementary diagnostic tool with recognition of its limited sensitivity 2
- When performing PET/CT, optimal timing during clinical workup and standardized protocols for patient preparation, scan acquisition, and image interpretation are essential 3