Combined Cardiac Fluorodeoxyglucose-Positron Emission Tomography/Magnetic Resonance Imaging Assessment of Myocardial Injury in Patients Who Recently Recovered From COVID-19

IMPORTANCE Although myocardial injury can occur with acute COVID-19, there is limited understanding of changes with myocardial metabolism in recovered patients. OBJECTIVE To examine myocardial metabolic changes early after recovery from COVID-19 using fluorodeoxyglucose-positron emission tomography (PET) and associate these changes to abnormalities in cardiac magnetic resonance imaging (MRI)-based function and tissue characterization measures and inflammatory blood markers. DESIGN, SETTING, AND PARTICIPANTS This prospective cohort study took place at a single-center tertiary referral hospital system. A volunteer sample of adult patients within 3 months of a diagnosis of COVID-19 who responded to a mail invitation were recruited for cardiac PET/MRI and blood biomarker evaluation between November 2020 and June 2021. EXPOSURES Myocardial inflammation as determined by focal fluorodeoxyglucose (FDG) uptake on PET. MAIN OUTCOMES AND MEASURES Demographic characteristics, cardiac and inflammatory blood markers, and fasting combined cardiac F-18-FDG PET/MRI imaging were obtained. All patients with focal FDG uptake at baseline returned for repeated PET/MRI and blood marker assessment 2 months later. RESULTS Of 47 included patients, 24 (51%) were female, and the mean (SD) age was 43 (13) years. The mean (SD) interval between COVID-19 diagnosis and PET/MRI was 67 (16) days. Most patients recovered at home during the acute infection (40 [85%]). Eight patients (17%) had focal FDG uptake on PET consistent with myocardial inflammation. Compared with those without FDG uptake, patients with focal FDG uptake had higher regional T2, T1, and extracellular volume (colocalizing with focal FDG uptake), higher prevalence of late gadolinium enhancement (6 of 8 [75%] vs 9 of 39 [23%], P=.009), lower left ventricular ejection fraction (mean [SD], 55%[4%] vs 62%[5%], P<.001), worse global longitudinal and circumferential strain (mean [SD], -16%[2%] vs -17%[2%], P=.02 and -18%[2%] vs -20% [2%], P=.047, respectively), and higher systemic inflammatory blood markers including interleukin 6, interleukin 8, and high-sensitivity C-reactive protein. Among patients with focal FDG uptake, PET/MRI, and inflammatory blood markers resolved or improved at follow-up performed a mean (SD) of 52 (17) days after baseline PET/MRI. CONCLUSIONS AND RELEVANCE In this study of patients recently recovered from COVID-19, myocardial inflammation was identified on PET in a small proportion of patients, was associated with cardiac MRI abnormalities and elevated inflammatory blood markers at baseline, and improved at follow-up.