The field of cardiac imaging is undergoing a rapid evolution with an ever expanding portfolio of high-quality evidence available to inform clinical practice guidelines and appropriate use criteria. In particular, it has long been a “holy grail” to identify a noninvasive test that provides both anatomical and functional information, which accurately predicts significant flow impairment by the “gold standard” of invasive fractional flow reserve (FFR). In this issue of JAMA Cardiology, Danad and colleagues1 address this issue in a report from the Prospective Comparison of Cardiac Positron Emission Tomography/Computed Tomography (PET/CT), Single-photon Emission Computed Tomography (SPECT)/CT perFusion imaging and CT Coronary Angiography (CTA) with Invasive Coronary Angiography (PACIFIC) study that compared the accuracy of pharmacologic stress nuclear, CTA, and hybrid imaging with invasive FFR measured in all coronary arteries. Although this is a relatively small, single-center clinical study, the findings from this report expand the growing evidence base on the relationship between anatomy and stress-induced ischemia with FFR. The authors are to be congratulated on completing this very ambitious and challenging clinical study that had more than 200 patients undergo a series of noninvasive tests that included stress SPECT, PET, and CTA, and invasive FFR determination. Expert core laboratories provided image interpretations that increased the rigor and minimized investigator bias in the presented findings. Importantly, the authors used state-of-the-art advanced imaging techniques, including measurements of coronary flow reserve with PET and hybrid PET- and SPECT-CTA. While not a randomized clinical trial, it adds significantly to the limited body of evidence that is currently available on the same patient undergoing all of these procedures.
Douglas PS, Shaw LJ. SPECT, PET, and CTA—Acronyms or Better Imaging?. JAMA Cardiol. Published online August 16, 2017. doi:10.1001/jamacardio.2017.2588