Persistent MRI Findings in Children Post Pfizer Vaccine Myopericarditis. Seattle Children's Hospital

In this study, the researchers followed up on children that had myocarditis from the second dose of the Pfizer-BioNTech vaccine. Most of the abnormalities had resolved except that the abnormal strain persisted for the majority of the patients.

https://www.youtube.com/watch?v=smKDRiiVIpY

What did he mean by this /sci?