Background Myocarditis following COVID-19 vaccination is a rare adverse event that was recently reported. Understanding the pattern and severity of myocardial injury in myocarditis caused by COVID-19 vaccination is imperative for improving care of the patients. Purpose To detect the pattern and severity of myocardial injury in patients with myocarditis following COVID-19 vaccination based on cardiac MRI findings. Study type Systematic review. Method Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, we systematically reviewed the literature by screening 2404 databases using boolean operators and the relevant key terms covering COVID-19 vaccine, myocarditis, and Cardiac MRI. We included all observational MRI studies on patients with suspected myocarditis following COVID-19 vaccination. Cardiac MRI findings, including T1, T2, ECV, LGE, and left ventricular ejection fraction, were extracted from included studies. Statistical tests As a single case series, individual-level patient data (IPD) studies were pooled with aggregated–level data (AD) studies through two-stage analyses. For this purpose, first, data from all case series and case reports with IPD were aggregated using one-stage IPD analyses. Results Based on our two-stage pooled analyses of IPD and AD studies, diagnosis of myocarditis using lake luoise criteria was confirmed in 74% (95% confidence interval (CI): 49% to 94%) of patients. Cardiac MRI abnormalities included elevated T2 in 67% (95% CI: 45% to 87%), myocardial LGE in 91% (95% CI: 81% to 99%) [having a subepicardial/midwall pattern: 99.5%], impaired LVEF (<50%) in 4% (95% CI: 0.0% to 9.0%). Also, elevated T1 and ECV (>30), reported only by some IPD studies, was detected in 72.5% (66/91) and 32% (16/50) of patients, respectively. Data conclusion Myocardial injury in COVID-19 vaccine-associated myocarditis may have a similar pattern compared to other forms of acute myocarditis. Despite other myocarditis, Preserved LVEF is a common finding in these patients. Funding Acknowledgement Type of funding sources: None.