Hybrid PET/MRI in Inflammatory Cardiac Diseases: A Systematic Review and Single-Center Experience

Figures

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  Chart 1. PRISMA 2020 flow diagram detailing the study selection process.

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  Chart 2. Illustration of diagnostic contribution of MRI, [18F]FDG-PET, and hybrid PET/MRI in patients with suspected myopericarditis. Abbreviations—MRI: magnetic resonance imaging; PET: positron emission tomography.

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  Chart 3. Illustration of diagnostic contribution of MRI, [18F]FDG-PET, and hybrid PET/MRI in patients with suspected endocarditis. Abbreviations—MRI: magnetic resonance imaging; PET: positron emission tomography.

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  Figure 1. 45-year-old female with suspected mitral valve endocarditis. (a) shows a cardiac MRI image revealing a mobile pseudonodular lesion on the posterolateral leaflet of the mitral valve, exhibiting late gadolinium enhancement (white arrow), which was inconclusive for the presence of inflammatory vegetation. (b) displays an FDG-PET image with pathological radiotracer uptake (SUVmax: 6.5). The integrated PET/MRI findings were diagnostic of mitral valve endocarditis (c,d).

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  Figure 2. 52-year-old female with suspected aortic valve endocarditis. (a) shows a cardiac MRI image revealing thickening at the level of the aortic root in the paravalvular region, with extension into the ascending thoracic aorta. Late gadolinium enhancement highlights linear intramyocardial fibrosis in the paravalvular aortic area (white arrow). (b,c) display FDG-PET images demonstrating diffuse increased metabolic radiotracer uptake (SUVmax: 5 and 8) (white arrows). The combined PET/MRI findings were diagnostic of mitral valve endocarditis with extension to the sternum—predominantly the manubrium—and the adjacent retrosternal soft tissues at the same level (d).

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  Figure 3. 56-year-old male with suspected myopericarditis. (a) displays an MRI image showing epicardial late gadolinium enhancement localized to the mid-basal inferolateral wall of the left ventricle (white dashed arrow) and the anterolateral wall of the right ventricle (white arrow), without evidence of myocardial edema (b). (c,d) show FDG-PET images with pathological focal glucose hyperaccumulation in the pericardium at the anterolateral aspect of the heart (SUVmax: 5), although precise anatomical localization was inconclusive (black arrows). The combined PET/MRI findings were conclusive for right ventricular myopericarditis (white arrows) (e,f).

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  Figure 4. 55-year-old male with suspected myopericarditis. (a) displays an MRI image showing a linear myo-epicardial late gadolinium enhancement in the mid-basal inferolateral wall of the left ventricle, suggestive of non-ischemic pattern fibrosis, possibly indicative of prior myocarditis. (b,c) show PET images with no distinct areas of radiotracer uptake in the myocardial walls, consistent with a negative result. The combined PET/MRI findings were conclusive for non-active myocarditis of the left ventricle (d).