Differential Diagnosis for Cardiac MRI Findings

The patient's cardiac MRI shows a normal left ventricle size, normal myocardial thickness, and normal wall function, but with an LVEF of 58% and mild subepicardial enhancement of the basal to mid inferior lateral wall. Based on these findings, the following differential diagnoses are considered:

• Single most likely diagnosis
  • Myocarditis: The presence of mild subepicardial enhancement, particularly in the basal to mid inferior lateral wall, is suggestive of myocardial inflammation, which is consistent with myocarditis. The patient's age and the fact that the left ventricle is not enlarged also support this diagnosis.
• Other Likely diagnoses
  • Cardiac sarcoidosis: This condition can cause subepicardial enhancement and reduced LVEF, similar to the patient's findings. However, it is less common in young adults without other systemic symptoms.
  • Idiopathic dilated cardiomyopathy: Although the left ventricle is not enlarged, the reduced LVEF and subepicardial enhancement could be indicative of early stages of dilated cardiomyopathy.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Acute coronary syndrome: Although the patient is young and has no risk factors, coronary artery disease or spontaneous coronary artery dissection could cause subepicardial enhancement and reduced LVEF. Missing this diagnosis could be catastrophic.
  • Cardiac lymphoma: This rare condition can cause subepicardial enhancement and reduced LVEF, and is often associated with other systemic symptoms. However, it is essential to consider this diagnosis to avoid delayed treatment.
• Rare diagnoses
  • Chagas disease: This parasitic infection can cause myocarditis and subepicardial enhancement, particularly in endemic areas. However, it is rare in non-endemic areas and would require specific travel or exposure history.
  • Giant cell myocarditis: This rare condition can cause subepicardial enhancement and reduced LVEF, but is often associated with other systemic symptoms and would require biopsy for diagnosis.