BOLD new directions in myocardial ischemia imaging-myocardial oxygenation assessment by cardiac magnetic resonance.

Myocardial ischemia results from an imbalance between oxygen supply and demand. After coronary occlusion, oxygen supply and demand mismatch produces a series of physiological alterations that can precede clinical symptoms (1). Impaired myocardial perfusion is an early event in the “ischemic cascade” that can be assessed using clinically available noninvasive imaging. Both extent and severity of perfusion deficits have been shown to predict longitudinal clinical outcomes, including cardiovascular mortality risk (2). Accordingly, current American College of Cardiology/ American Heart Association guidelines support of stress perfusion imaging for assessment of symptomatic patients with intermediate or high pre-test likelihood of coronary artery disease (CAD) (3).