Cardiac MRI for the Assessment of Myocardial Viability

Diagnosis of myocardial viability after infarction focuses on the prediction of functional improvement of dysfunctional myocardium after revascularization therapy. Magnetic resonance imaging (MRI) provides morphological and functional approaches for the assessment of myocardial viability. The morphological approach is based on the detection of the ratio viable/non‐viable cells. The end‐diastolic wall thickness is an indirect parameter of this ratio, because thinned myocardium contains a reduced number of viable cells. This approach is easy to perform and has a high sensitivity, but a low specificity and can only be used 4 months after myocardial infarction due to infarct healing processes. Delayed enhancement allows for direct visualization of necrotic or scarred tissue. By measuring the transmural extent of delayed enhancement, the probability of mechanical improvement can precisely be given. Imaging of microvascular obstruction by first‐pass perfusion or delayed enhancement gives additional information on viability and patient prognosis. Low‐dose dobutamine‐stress as the functional approach has a good sensitivity with a high specificity for the prediction of wall motion improvement and may provide additional information in patients with transmural extent of delayed enhancement between 1 and 75%. In conclusion, cardiac MRI offers several clinically usable approaches for the assessment of myocardial viability and is about to become the method of choice in the near future.