Line 11:1·"Echocardiography" is not a recognised heading for this article type.
Oxford Comma
suggestion
"After administration of gadolinium-based contrast agents, epicardium and parietal/fibrous pericardium might be outlined by a variable amount of enhancement subject to the degree of inflammation 1."
Line 17:57·Use the Oxford comma in 'agents, epicardium and parietal'.