JNC: Infection vs inflammation in prosthetic heart valves by [18F]FDGPET / CT: A practical tutorial for accurate interpretation-Infection vs inflammation in prosthetic heart valves by [18F]FDGPET/ CT: A practical tutorial for accurate interpretation3

Infection vs inflammation in prosthetic heart valves by [18F]FDGPET/ CT: A practical tutorial for accurate interpretation3

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The document provides a comprehensive tutorial on using [18F]FDG-PET/CT imaging for distinguishing infection from inflammation in prosthetic heart valves. The study addresses the challenge of differentiating between these conditions, particularly in the early postoperative period, due to potential postsurgical metabolic activity that can complicate diagnosis. The detailed guidelines emphasize the characteristic patterns of [18F]FDG uptake combined with anatomical findings that allow for differentiation between infection and postoperative inflammation, even within three months of surgery.<br /><br />Key points include:<br /><br />1. The PET/CT scan interpretation relies on visual assessment of [18F]FDG uptake pattern and intensity, alongside semiquantitative values that provide additional information. Although no validated threshold values exist to definitively confirm infection, certain patterns (e.g., intense focal or heterogeneous uptake) suggest infection.<br /><br />2. A novel metric, the valve uptake index (VUI), aids in differentiating normal from abnormal uptake patterns, enhancing diagnostic accuracy.<br /><br />3. Combining PET with cardiac CT enhances anatomical lesion detection, particularly those indicative of endocarditis, maximizing diagnostic performance. Cardio-dedicated PET/CT studies with proper patient preparation and specific acquisition techniques are advocated.<br /><br />4. Cases illustrated (e.g., patients with early postoperative infection or reactive inflammation) show how PET/CT findings can lead to reclassification of suspected prosthetic valve endocarditis (PVE) cases when echocardiography is inconclusive.<br /><br />5. The document advises that knowledge of the surgical technique and implanted materials is crucial for accurate image interpretation, helping avoid misinterpretation and false positives.<br /><br />Ultimately, the authors highlight the significant role of [18F]FDG-PET/CT in the diagnostic workup of PVE and stress the importance of integrating imaging results with clinical findings for accurate diagnosis and effective management. The tutorial emphasizes the potential removal of the previous 3-month scanning restriction post-surgery and the utility of PET/CT imagery across different clinical scenarios and patient types, despite persistent challenges related to the specificity of [18F]FDG.

Keywords

[18F]FDG-PET/CT

prosthetic heart valves

infection differentiation

postoperative inflammation

PET/CT scan interpretation

valve uptake index

cardiac CT

endocarditis detection

prosthetic valve endocarditis

diagnostic workup