Illuminating the Path Forward in Cardiac Regeneration Using Strain Magnetic Resonance Imaging

In recent years, several important studies have shown advantages of strain imaging over imaging of ejection fraction (EF) for diagnostic and prognostic applications in heart disease. For example, global longitudinal strain assessed using echocardiography has demonstrated superior performance compared with echocardiographic assessment of EF for predicting major adverse cardiac events in heart failure, myocardial infarction, and valvular heart disease.1,2 Likewise, strain is now recommended in addition to EF to identify systolic dysfunction in chemotherapy patients.3 Using accurate and reproducible magnetic resonance strain imaging methods, such as myocardial tagging and displacement encoding with stimulated echoes, strain detects subclinical systolic dysfunction in diabetics and obese children at stages where changes in EF are not seen.4,5 Using regional analysis methods, strain imaging shows high potential for detecting late activating regions and optimizing the implementation of cardiac resynchronization therapy, providing more valuable information than cine imaging.6 This recent wave of impressive strain imaging successes has led to the suggestion that strain imaging could potentially replace or supercede EF.7 Within the field of cardiac regeneration, the efficacy of emerging therapies is often assessed by measuring longitudinal changes in EF in large groups of small animals. However, such measurements do not directly interrogate contractile function localized to specific regions that were damaged and treated. In this issue of Circulation: Cardiovascular Imaging , the article by Qin et al8 from the laboratory of Dr Joseph Wu extends the successful application of strain imaging into the realm of preclinical cardiac regenerative therapies, showing that …