Department of Cardiology, Cardiovascular Center, Seoul National University Bundang Hospital, Seongnam 463-707, Korea.
Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul 138-736, Korea.
Abstract
Cardiac computed tomography (CT) has emerged as a noninvasive modality for the assessment of coronary artery disease (CAD), and has been rapidly integrated into clinical cares. CT has changed the traditional risk stratification based on clinical risk to image-based identification of patient risk. Cardiac CT, including coronary artery calcium score and coronary CT angiography, can provide prognostic information and is expected to improve risk stratification of CAD. Currently used conventional cardiac CT, provides accurate anatomic information but not functional significance of CAD, and it may not be sufficient to guide treatments such as revascularization. Recently, myocardial CT perfusion imaging, intracoronary luminal attenuation gradient, and CT-derived computed fractional flow reserve were developed to combine anatomical and functional data. Although at present, the diagnostic and prognostic value of these novel technologies needs to be evaluated further, it is expected that all-in-one cardiac CT can guide treatment and improve patient outcomes in the near future.
Fig. 1Case of computed tomography (CT) myocardial perfusion imaging. 54-year-old male patient with chest pain. Coronary CT angiography (A) showed stenosis in proximal left anterior descending artery (white arrow). Invasive coronary angiography (B) also showed presence of significant stenosis in proximal LAD (white arrow), and fractional flow reserve of 0.79 confirmed functional significance of lesion. Stress (C) and rest (D) CT myocardial perfusion imaging showed ischemia (black arrowheads) of LAD territory (images were provided by Dr. Dong Hyun Yang from Asan Medical Center, Korea). LAD = left anterior descending artery.Fig. 2Case of computed tomography (CT) myocardial perfusion imaging. 64-year-old male patient with history of percutaneous coronary intervention to right coronary artery (RCA) was referred with effort angina. Coronary CT angiography (A) showed stenosis in RCA stent (white arrow), and stress (B) and rest (C) CT myocardial perfusion imaging showed ischemia (black arrowheads) of RCA territory. Invasive coronary angiography (D) confirmed presence of significant in-stent restenosis (black arrow) (Images were provided by Dr. Dong Hyun Yang from Asan Medical Center, Korea).Fig. 3Diagnostic accuracy of coronary computed tomography (CT) angiography and CT myocardial perfusion imaging to detect functionally significant stenosis, defined as fractional flow reserve ≤ 0.80 (27). PPV = positive predictive value, NPV = negative predictive valueFig. 4Case of computed tomography-derived computed fractional flow reserve (FFRCT). 59-year-old female patient complained effort angina. Coronary CT angiography detected (A) diffuse intermediate stenosis of left anterior descending artery (LAD) (white arrowheads) and (B) focal intermediate stenosis of left circumflex artery (LCX) (white arrow). Computation of FFRCT demonstrated that (C) LAD stenosis was not hemodynamically significant with FFRCT value over 0.8 (black arrowhead), and LCX stenosis is ischemia-causing lesion with FFRCT value of less than 0.8 (black arrow) (Images were provided by Dr. Bon-Kwon Koo from Seoul National University Hospital, Korea).Fig. 5Diagnostic accuracy of coronary computed tomography (CT) angiography and FFRCT to detect functionally significant stenosis, defined as fractional flow reserve ≤ 0.80 (38). PPV = positive predictive value, NPV = negative predictive value
