Coronary artery function: out of the cath lab and into the magnet.

Exclusive dependence on invasive angiography to image coronary artery anatomy is now a thing of the past, thanks to the success of coronary computed tomography angiography (CTA). But evaluation of coronary artery function has remained largely invasive despite the development of cardiac magnetic resonance (CMR) methods to image coronary artery lumens and flow in the 1990s (1,2). Invasive studies of coronary flow reserve with the use of intracoronary Doppler or pressure measurements and of coronary endothelial function, assessed from changes in angiographic lumen size and flow after intracoronary acetylcholine or cold pressor stimulation, have largely defined our understanding of coronary artery function (3–5).