A strong impact to the front of the chest oftentimes results in myocardial contusion.
A fractured sternum indicates high kinetic energy at the impact and elevated troponin levels and chest pain after such an injury confirm myocardial contusion.
Myocardial edema was still present 2.5 months after the injury, which is quite a long period and usually resolves much faster. Such a long period of resolution is sometimes seen with cases of myocardial infarction as well as from myocardial contusion.
Transmural late gadolinium enhancement indicates myocardial scar tissue and could indicate myocardial infarction, but it is relatively small and does not correspond to coronary vascular territories. It could correspond to obstruction of a small septal branch, though. Once again - it is still unclear, whether myocardial changes after contusion come from direct injury, indirect injury (ischemia) due to damage to the local vessels or both.
The sternal fracture at the level of the myocardial late gadolinium enhancement is quite a typical finding myocardial contusion.