To the Editor Coronary computed tomography angiography (cCTA)–based fractional flow reserve (FFR-CT) is an evolving technology of disruptive potential to noninvasively determine the hemodynamic significance of a coronary artery stenosis. The systematic review by Cook et al1 provides an excellent overview on the status of this innovative method. In their Methods section, the authors mention the FFR-CT algorithm approved by the US Food and Drug Administration in late 2014.1 However, technology and evidence in this field are rapidly evolving, which adds new facets to their discussion.