{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,11]],"date-time":"2026-09-11T11:24:05Z","timestamp":1789125845436,"version":"build-2803163510"},"reference-count":23,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2026,9,11]],"date-time":"2026-09-11T00:00:00Z","timestamp":1789084800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Diagnostics"],"abstract":"<jats:p>Background: Hybrid positron emission tomography\/magnetic resonance imaging (PET\/MRI) enables simultaneous assessment of myocardial metabolism and CMR tissue characteristics. We investigated whether integrated 18F-FDG PET\/MRI could identify persistent metabolic abnormalities approximately 6 months after acute myocarditis, including abnormalities discordant with concomitant CMR oedema markers. Methods: In this retrospective single-centre study, 20 consecutive patients with a previous episode of acute myocarditis underwent integrated cardiac 18F-FDG PET\/MRI approximately 6 months after the acute event. Focal myocardial FDG uptake, myocardial SUVmax and SUVmean, target-to-background ratios, T2 mapping, late gadolinium enhancement (LGE), and ventricular function were assessed within the hybrid examination. Results: Hybrid PET\/MRI was performed at a median of 202 days (interquartile range [IQR], 173\u2013221) after the acute episode. Four patients (20%) had non-diagnostic PET because of inadequate myocardial glucose suppression. Among 16 evaluable patients, four (25%) remained PET-positive with focal myocardial FDG uptake. Their myocardial SUVmax was 2.85 (IQR, 2.58\u20133.25) versus 1.65 (IQR, 1.38\u20131.80) in PET-negative patients (p = 0.001), and the myocardium-to-blood-pool ratio was 1.03 (IQR, 1.00\u20131.19) versus 0.82 (IQR, 0.75\u20130.86), respectively (p = 0.003). None of the four PET-positive patients had myocardial oedema on concomitant T2 mapping, whereas all had persistent LGE. One PET-negative patient showed persistent CMR oedema. Conclusions: Integrated PET\/MRI identified persistent focal metabolic abnormalities in 25% of evaluable patients approximately 6 months after acute myocarditis, despite absent concomitant CMR oedema. Although the cohort is small and contemporary longitudinal clinical characterisation is limited, these hybrid-imaging findings support further investigation of PET\/MRI as a tool for phenotyping the post-acute phase of myocarditis.<\/jats:p>","DOI":"10.3390\/diagnostics16182941","type":"journal-article","created":{"date-parts":[[2026,9,11]],"date-time":"2026-09-11T10:51:37Z","timestamp":1789123897000},"page":"2941","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Persistent Focal Myocardial 18F-FDG Uptake Discordant with CMR Oedema on Hybrid PET\/MRI Six Months After Acute Myocarditis"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0009-0009-0019-7812","authenticated-orcid":false,"given":"Guillaume","family":"Reverdito","sequence":"first","affiliation":[{"name":"Department of Radiology, H\u00f4pital Henri Mondor, 94000 Cr\u00e9teil, France"},{"name":"Department of Radiology, H\u00f4pital Marie Lannelongue, Fondation Paris-Saint Joseph, 92360 Le Plessis-Robinson, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-2225-9267","authenticated-orcid":false,"given":"Hichem","family":"Sakhi","sequence":"additional","affiliation":[{"name":"Department of Radiology, H\u00f4pital Marie Lannelongue, Fondation Paris-Saint Joseph, 92360 Le Plessis-Robinson, France"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"467","DOI":"10.1093\/ehjci\/jey119","article-title":"Longitudinal 18F-FDG PET imaging in a rat model of autoimmune myocarditis","volume":"20","author":"Werner","year":"2019","journal-title":"Eur. 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