Hybrid Imaging in the Assessment of Myocardial Ischemia and Viability

Myocardial ischemia results from a reduction in blood flow as a consequence of a coronary stenosis, which produces ischemia in the myocardial territories irrigated by the stenotic artery. Myocardial viability is a concept that derived from several studies in which it was observed that, even if revascularization occurred, an irreversible left ventricular contractile dysfunction remained. The terms “stunned” and “hibernating” myocardium have been traditionally associated with the viable myocardium, and many controversies still exist on the most appropriate method to assess the presence and extent of viable myocardium. During the last decades, many efforts have been made to identify the best method to determine the viability of the myocardial tissue. Due to the fact that none of the stand-alone imaging methods provide sufficient data about myocardial viability, new methods for the investigation of myocardial viability became necessary. Thus, the concept of hybrid imaging was developed, consisting in the association of different imaging techniques, finally resulting in a single image that offers all the details provided by the two isolated methods of diagnosis, therefore being more precise in regards to the identification of viable myocardium territory. This review aims to appraise the recent studies related to myocardial viability investigated with hybrid imaging.