Segmentation-based algorithms to quantify nonviable myocardium after delayed contrast-enhanced computed tomography: defining what’s dead

Abstract

The ability to distinguish dysfunctional but viable myocardium from nonviable tissue after acute or chronic ischemia has important implications for the therapeutic management of patients with coronary artery disease. In the acute phase, myocardial revascularization in patients with viable myocardium can improve ventricular dysfunction 1 Alderman E.L. Fisher L.D. Litwin P. Kaiser G.C. Myers W.O. Maynard C. Levine F. Schloss M. Results of coronary artery surgery in patients with poor left ventricular function (CASS). Circulation. 1983; 68: 785-795 Crossref PubMed Scopus (698) Google Scholar and long-term survival, 2 Pagley P.R. Beller G.A. Watson D.D. Gimple L.W. Ragosta M. Improved outcome after coronary bypass surgery in patients with ischemic cardiomyopathy and residual myocardial viability. Circulation. 1997; 96: 793-800 Crossref PubMed Scopus (358) Google Scholar whereas image-based characterization of myocardial scar structure in the setting of chronic ischemia can identify those patients with hibernating myocardium who may achieve functional systolic recovery with revascularization. 3 Wakimoto H. Maguire C.T. Kovoor P. Hammer P.E. Gehrmann J. Triedman J.K. Berul C.I. Induction of atrial tachycardia and fibrillation in the mouse heart. Cardiovasc Res. 2001; 50: 463-473 Crossref PubMed Scopus (78) Google Scholar The assessment of both acute and chronic myocardial viability using delayed enhanced magnetic resonance imaging (de-MRI) is considered the standard for myocardial viability assessment. As the clinical indications for implantable cardiac defibrillators and biventricular pacing therapy continue to expand, however, development and validation of alternative imaging methods with similar anatomic, functional, and viability imaging capabilities are needed to accommodate this growing population of patients.