JACC: CARDIOVASCULAR IMAGING
VOL. 6, NO. 10, 2013
ª 2013 BY THE AMERICAN COLLEGE OF CARDIOLOGY FOUNDATION
ISSN 1936-878X/$36.00
PUBLISHED BY ELSEVIER INC.
http://dx.doi.org/10.1016/j.jcmg.2013.07.006
EDITORIAL COMMENT
CT Assessment of Coronary Artery Disease Trends and Clinical Implications* Paul Schoenhagen, MD,y Marc Dewey, MDz Cleveland, Ohio; and Berlin, Germany
In this issue of iJACC, Bettencourt et al. (1) compare myocardial scar imaging with computed tomography (CT) and cardiac magnetic resonance (CMR). The data are based on a comprehensive clinical CT protocol, including coronary computed See page 1062
tomography angiography (CTA), myocardial stress– rest computed tomography perfusion (CTP), and computed tomography delayed enhancement scar imaging (CTDE). The report is part of a series of recent papers using apparently the same patient cohort (1–3). The prior publications demonstrate that stress CTP imaging has diagnostic accuracy comparable to stress–rest CMR and, when added to anatomic assessment of luminal stenosis alone, in*Editorials published in JACC: Cardiovascular Imaging reflect the views of the authors and do not necessarily represent the views of JACC: Cardiovascular Imaging or the American College of Cardiology. From the yCleveland Clinic, Imaging Institute and Heart and Vascular Institute, Cardiovascular Imaging, Cleveland, Ohio; and the zDepartment of Radiology, Charité, Berlin, Germany. Dr. Dewey has received grant support from GE Healthcare, Bracco, Guerbet, Toshiba Medical Systems, Heisenberg Program of the German Research Foundation (DFG) for a Professorship (DE 1361/14-1), European Regional Development Fund (20072013 2/05, 20072013 2/48), German Heart Foundation/German Foundation of Heart Research (F/23/08, F/27/10), and a joint program of the DFG and the German Federal Ministry of Education and Research (BMBF) for cardiovascular imaging meta-analyses (01KG1013, 01KG1110); is a consultant to Guerbet and a principal investigator of multicenter studies (CORE-64 and -320) on coronary CT angiography sponsored by Toshiba Medical Systems; has received lecture fees from Toshiba Medical Systems, Guerbet, and Bayer (Schering-Berlex); is on the Speakers’ Bureau of Toshiba Medical Systems, Guerbet, Cardiac MR Academy Berlin, and Bayer-Schering; has institutional master research agreements with Siemens Medical Solutions, Philips Medical Systems, and Toshiba Medical Systems, the terms of these arrangements are managed by the legal department of Charité, Universitatsmedizin Berlin; is the author of two books Coronary CT Angiography (Springer, 2009) and Cardiac CT (Springer, 2011); and teaches Cardiac CT Courses in Berlin: www.ct-kurs.de. Prof. Schoenhagen has reported that he has no relationships relevant to the contents of this paper to disclose.
creases the diagnostic accuracy of CTA. In the current paper, the authors show that the addition of CTDE does not provide further diagnostic value for the identification of patients with functionally significant CAD (defined as luminal stenosis by conventional angiography $90% [$50% in the left main stem], or fractional flow reserve [FFR] #0.8 in vessels >2 mm). What future impact could the results have for cardiac CT? The diagnostic goals in symptomatic patients with suspected CAD are: 1) identification and localization of hemodynamically significant lesions, defined based on severity of luminal stenosis and/or effect on myocardial perfusion; 2) prediction of risk for future cardiovascular events; and 3) optimization of subsequent therapeutic management. Based on a significant amount of data from singleand multi-center studies intraindividually comparing noninvasive with invasive coronary angiography, CTA has been shown to be a useful noninvasive test (4). CTA is characterized by a high negative predictive value (>95%) and low negative likelihood ratio (75 ms vs. >20 ms), with increased susceptibility to motion artifacts; and 2) lower pixel dimensions (spatial resolution 0.5 mm2 vs. 0.1 mm2), with increased susceptibility to volume averaging. Volume averaging is most obvious for calcified plaques (“calcium blooming”) and indicates that a small calcified subvolume of dense calcium can increase the density of an entire voxel above the calcium threshold. These limitations degrade image quality
Schoenhagen and Dewey Editorial Comment
JACC: CARDIOVASCULAR IMAGING, VOL. 6, NO. 10, 2013 OCTOBER 2013:1072–4
specifically in calcified, moderate-to-severe stenosis and are associated with false-positive CTA results, potentially leading to increased downstream testing (8,9). Therefore, coronary CTA is typically not recommended in patients with known significant CAD, most coronary stents, diffuse calcified atherosclerotic disease, and those with a high and irregular heart rate, excluding a significant percentage of patients. These technical limitations have been alleviated, but not resolved, with the latest, most advanced scanner generations, and only gradual advances are expected in the near future. Another approach to increase the value of CT is to evaluate additional characteristics of coronary lesions, and specifically, their functional significance, that is, myocardial ischemia/scar. The role of perfusion imaging is well established with positron emission tomography/ single-photon emission computed tomography, stress echocardiography, and stress CMR (10). Stress CTP is feasible, but data are still relatively limited (11,12). The series of papers by Bettencourt et al. (1–3) and recently published results from CARS-320 (Coronary Artery Stent Evaluation With 320-slice Computed Tomography–The CArS 320 Study) (13) provide evidence that combined coronary CTA and myocardial CTP may allow improved diagnostic accuracy compared with CTA alone, in patients with native CAD or stents. In the current report, Bettencourt et al. (1) demonstrate that the addition of CTDE scar imaging did not add further diagnostic value. Segments with scar (CTDEþ), but without ischemia (CTP) were reclassified as significant disease. However, most segments with scar also demonstrated ischemia (9 of 11), explaining the lack of diagnostic impact. The negative results may simply demonstrate that scar imaging is not a good marker for the identification of functionally significant CAD. In fact, data from positron emission tomography/single-photon emission computed tomography and CMR demonstrate that the value of scar imaging is rather its prognostic value for future cardiovascular events and mortality (14). The current study was too small to look at followup events, and there are very limited data describing the prognostic value of CTDE. On the other hand, extensive data have accumulated demonstrating the
prognostic information of disease burden defined by CTA (stenosis and plaque burden) on future cardiovascular events (6,15). Specifically, a negative coronary CTA is associated with a pooled annualized event rate of 0.17% per year for major adverse cardiac events and 0.15% for death or myocardial infarction, comparable to healthy, lowrisk populations adjusted for age. On the basis of the preceding, we believe that the following trends can be identified for appropriate use of cardiac CT: Improvement in the selection of the most suitable patient populations remains important (16). Evaluation of the impact of CTA on therapeutic management is critical and is the objective of the large U.S. multicenter PROMISE (PROspective Multicenter Imaging Study for Evaluation of Chest Pain) (17) and RESCUE (Randomized Evaluation of Patients With Stable Angina Comparing Diagnostic Examinations) trials (18). In patients with intermediate stenoses on CTA, subsequent stress CTP may direct management, similar to invasive FFR (19). This is examined in the CORE320 (Combined Coronary Atherosclerosis and Myocardial Perfusion Evaluation Using 320 Detector Row Computed Tomography) trial (20). The recently described concept of CT-FFR is interesting, but incompletely understood, and further evaluation will be important to define its potential clinical role (21). Lastly, although feasible and intriguing, current data are not sufficient to support clinical use of CTDE scar imaging in the diagnostic work-up of patients with suspected CAD. Coronary CTA has developed into a valuable diagnostic option for certain symptomatic patient populations. CTP and perhaps CTDE will likely expand CTA’s application, but further evaluation of their impact on therapeutic decision making is necessary, optimally in trials with clinical endpoints. requests and correspondence: Prof. Paul Schoenhagen, Cleveland Clinic, Imaging Institute and Heart and Vascular Institute, Cardiovascular Imaging, Desk J1-4, 9500 Euclid Avenue, Cleveland, Ohio 44195. E-mail: [email protected].
Reprint
REFERENCES
1. Bettencourt N, Ferreira ND, Leite D, et al. CAD detection in patients with
intermediate-high pre-test probability: low-dose CT delayed enhancement
detects ischemic myocardial scar with moderate accuracy but does not
1073
1074
Schoenhagen and Dewey Editorial Comment
improve performance of a stress-rest CT perfusion protocol. J Am Coll Cardiol Img 2013;6:1062–71. 2. Bettencourt N, Chiribiri A, Schuster A, et al. Direct comparison of cardiac magnetic resonance and multidetector computed tomography stress-rest perfusion imaging for detection of coronary artery disease. J Am Coll Cardiol 2013;61:1099–107. 3. Bettencourt N, Chiribiri A, Schuster A, et al. Cardiac magnetic resonance myocardial perfusion imaging for detection of functionally significant obstructive coronary artery disease: a prospective study. Int J Cardiol 2012 Oct 24 [E-pub ahead of print]. 4. Schuetz GM, Zacharopoulou NM, Schlattmann P, Dewey M. Metaanalysis: noninvasive coronary angiography using computed tomography versus magnetic resonance imaging. Ann Intern Med 2010;152:167–77. 5. Schlattmann P, Schuetz GM, Dewey M. Influence of coronary artery disease prevalence on predictive values of coronary CT angiography: a metaregression analysis. Eur Radiol 2011; 21:1904–13. 6. Hulten EA, Carbonaro S, Petrillo SP, Mitchell JD, Villines TC. Prognostic value of cardiac computed tomography angiography: a systematic review and meta-analysis. J Am Coll Cardiol 2011;57:1237–47. 7. Hulten E, Pickett C, Bittencourt MS, et al. Outcomes after coronary computed tomography angiography in the emergency department: a systematic review and meta-analysis of randomized, controlled trials. J Am Coll Cardiol 2013;61:880–92. 8. Arbab-Zadeh A, Miller JM, Rochitte CE, et al. Diagnostic accuracy of computed tomography coronary angiography according to pre-test probability of coronary artery disease and severity of coronary arterial calcification. The CORE-64 International
JACC: CARDIOVASCULAR IMAGING, VOL. 6, NO. 10, 2013 OCTOBER 2013:1072–4
(Coronary Artery Evaluation Using 64-Row Multidetector Computed Tomography Angiography) International Multicenter Study. J Am Coll Cardiol 2012;59:379–87. 9. Nissen SE. Coronary computed tomography angiography. The challenge of coronary calcium. J Am Coll Cardiol 2012;59:388–9. 10. Hamon M, Fau G, Née G, Ehtisham J, Morello R, Hamon M. Meta-analysis of the diagnostic performance of stress perfusion cardiovascular magnetic resonance for detection of coronary artery disease. J Cardiovasc Magn Reson 2010;12:29. 11. Rocha-Filho JA, Blankstein R, Shturman LD, et al. Incremental value of adenosine-induced stress myocardial perfusion imaging with dual-source CT at cardiac CT angiography. Radiology 2010;254:410–9. 12. Tashakkor AY, Nicolaou S, Leipsic J, Mancini GB. The emerging role of cardiac computed tomography for the assessment of coronary perfusion: a systematic review and meta-analysis. Can J Cardiol 2012;28:413–22. 13. Rief M, Zimmermann E, Stenzel F, et al. CT angiography and myocardial CT perfusion in patient with coronary stents: prospective intraindividual comparison with conventional coronary angiography. J Am Coll Cardiol 2013 Jun 14 [E-pub ahead of print]. 14. Kwon DH, Halley CM, Carrigan TP, et al. Extent of left ventricular scar predicts outcomes in ischemic cardiomyopathy patients with significantly reduced systolic function: a delayed hyperenhancement cardiac magnetic resonance study. J Am Coll Cardiol Img 2009;2:34–44. 15. Bamberg F, Sommer WH, Hoffmann V, et al. Meta-analysis and systematic review of the long-term predictive value of assessment of coronary atherosclerosis by contrastenhanced coronary computed
tomography angiography. J Am Coll Cardiol 2011;57:2426–36. 16. Schuetz GM, Schlattmann P, Achenbach S, et al. Individual patient data meta-analysis for the clinical assessment of coronary computed tomography angiography: protocol of the Collaborative Meta-Analysis of Cardiac CT (CoMe-CCT). Syst Rev 2013;2:13. 17. PROMISE (PROspective Multicenter Imaging Study for Evaluation of Chest Pain). Available at: http://www.clinical trials.gov/ct2/show/NCT01174550? term¼NCT01174550. Accessed August 13, 2013. 18. RESCUE trials (Randomized Evaluation of Patients With Stable Angina Comparing Diagnostic Examinations). Available at: http://www.clinicaltrials. gov/ct2/show/NCT01262625?term¼ NCT01262625. Accessed August 13, 2013. 19. De Bruyne B, Pijls NH, Kalesan B, et al. Fractional flow reserve-guided PCI versus medical therapy in stable coronary disease. N Engl J Med 2012; 367:991–1001. 20. Vavere AL, Simon GG, George RT, et al. Diagnostic performance of combined noninvasive coronary angiography and myocardial perfusion imaging using 320 row detector computed tomography: design and implementation of the CORE320 multicenter, multinational diagnostic study. J Cardiovasc Comput Tomogr 2011;5:370–81. 21. Min JK, Leipsic J, Pencina MJ, et al. Diagnostic accuracy of fractional flow reserve from anatomic CT angiography. JAMA 2012;308:1237–45.
Key Words: CMR - delayed enhancement - MDCT tomography.
VOL. 6, NO. 10, 2013
ª 2013 BY THE AMERICAN COLLEGE OF CARDIOLOGY FOUNDATION
ISSN 1936-878X/$36.00
PUBLISHED BY ELSEVIER INC.
http://dx.doi.org/10.1016/j.jcmg.2013.07.006
EDITORIAL COMMENT
CT Assessment of Coronary Artery Disease Trends and Clinical Implications* Paul Schoenhagen, MD,y Marc Dewey, MDz Cleveland, Ohio; and Berlin, Germany
In this issue of iJACC, Bettencourt et al. (1) compare myocardial scar imaging with computed tomography (CT) and cardiac magnetic resonance (CMR). The data are based on a comprehensive clinical CT protocol, including coronary computed See page 1062
tomography angiography (CTA), myocardial stress– rest computed tomography perfusion (CTP), and computed tomography delayed enhancement scar imaging (CTDE). The report is part of a series of recent papers using apparently the same patient cohort (1–3). The prior publications demonstrate that stress CTP imaging has diagnostic accuracy comparable to stress–rest CMR and, when added to anatomic assessment of luminal stenosis alone, in*Editorials published in JACC: Cardiovascular Imaging reflect the views of the authors and do not necessarily represent the views of JACC: Cardiovascular Imaging or the American College of Cardiology. From the yCleveland Clinic, Imaging Institute and Heart and Vascular Institute, Cardiovascular Imaging, Cleveland, Ohio; and the zDepartment of Radiology, Charité, Berlin, Germany. Dr. Dewey has received grant support from GE Healthcare, Bracco, Guerbet, Toshiba Medical Systems, Heisenberg Program of the German Research Foundation (DFG) for a Professorship (DE 1361/14-1), European Regional Development Fund (20072013 2/05, 20072013 2/48), German Heart Foundation/German Foundation of Heart Research (F/23/08, F/27/10), and a joint program of the DFG and the German Federal Ministry of Education and Research (BMBF) for cardiovascular imaging meta-analyses (01KG1013, 01KG1110); is a consultant to Guerbet and a principal investigator of multicenter studies (CORE-64 and -320) on coronary CT angiography sponsored by Toshiba Medical Systems; has received lecture fees from Toshiba Medical Systems, Guerbet, and Bayer (Schering-Berlex); is on the Speakers’ Bureau of Toshiba Medical Systems, Guerbet, Cardiac MR Academy Berlin, and Bayer-Schering; has institutional master research agreements with Siemens Medical Solutions, Philips Medical Systems, and Toshiba Medical Systems, the terms of these arrangements are managed by the legal department of Charité, Universitatsmedizin Berlin; is the author of two books Coronary CT Angiography (Springer, 2009) and Cardiac CT (Springer, 2011); and teaches Cardiac CT Courses in Berlin: www.ct-kurs.de. Prof. Schoenhagen has reported that he has no relationships relevant to the contents of this paper to disclose.
creases the diagnostic accuracy of CTA. In the current paper, the authors show that the addition of CTDE does not provide further diagnostic value for the identification of patients with functionally significant CAD (defined as luminal stenosis by conventional angiography $90% [$50% in the left main stem], or fractional flow reserve [FFR] #0.8 in vessels >2 mm). What future impact could the results have for cardiac CT? The diagnostic goals in symptomatic patients with suspected CAD are: 1) identification and localization of hemodynamically significant lesions, defined based on severity of luminal stenosis and/or effect on myocardial perfusion; 2) prediction of risk for future cardiovascular events; and 3) optimization of subsequent therapeutic management. Based on a significant amount of data from singleand multi-center studies intraindividually comparing noninvasive with invasive coronary angiography, CTA has been shown to be a useful noninvasive test (4). CTA is characterized by a high negative predictive value (>95%) and low negative likelihood ratio (75 ms vs. >20 ms), with increased susceptibility to motion artifacts; and 2) lower pixel dimensions (spatial resolution 0.5 mm2 vs. 0.1 mm2), with increased susceptibility to volume averaging. Volume averaging is most obvious for calcified plaques (“calcium blooming”) and indicates that a small calcified subvolume of dense calcium can increase the density of an entire voxel above the calcium threshold. These limitations degrade image quality
Schoenhagen and Dewey Editorial Comment
JACC: CARDIOVASCULAR IMAGING, VOL. 6, NO. 10, 2013 OCTOBER 2013:1072–4
specifically in calcified, moderate-to-severe stenosis and are associated with false-positive CTA results, potentially leading to increased downstream testing (8,9). Therefore, coronary CTA is typically not recommended in patients with known significant CAD, most coronary stents, diffuse calcified atherosclerotic disease, and those with a high and irregular heart rate, excluding a significant percentage of patients. These technical limitations have been alleviated, but not resolved, with the latest, most advanced scanner generations, and only gradual advances are expected in the near future. Another approach to increase the value of CT is to evaluate additional characteristics of coronary lesions, and specifically, their functional significance, that is, myocardial ischemia/scar. The role of perfusion imaging is well established with positron emission tomography/ single-photon emission computed tomography, stress echocardiography, and stress CMR (10). Stress CTP is feasible, but data are still relatively limited (11,12). The series of papers by Bettencourt et al. (1–3) and recently published results from CARS-320 (Coronary Artery Stent Evaluation With 320-slice Computed Tomography–The CArS 320 Study) (13) provide evidence that combined coronary CTA and myocardial CTP may allow improved diagnostic accuracy compared with CTA alone, in patients with native CAD or stents. In the current report, Bettencourt et al. (1) demonstrate that the addition of CTDE scar imaging did not add further diagnostic value. Segments with scar (CTDEþ), but without ischemia (CTP) were reclassified as significant disease. However, most segments with scar also demonstrated ischemia (9 of 11), explaining the lack of diagnostic impact. The negative results may simply demonstrate that scar imaging is not a good marker for the identification of functionally significant CAD. In fact, data from positron emission tomography/single-photon emission computed tomography and CMR demonstrate that the value of scar imaging is rather its prognostic value for future cardiovascular events and mortality (14). The current study was too small to look at followup events, and there are very limited data describing the prognostic value of CTDE. On the other hand, extensive data have accumulated demonstrating the
prognostic information of disease burden defined by CTA (stenosis and plaque burden) on future cardiovascular events (6,15). Specifically, a negative coronary CTA is associated with a pooled annualized event rate of 0.17% per year for major adverse cardiac events and 0.15% for death or myocardial infarction, comparable to healthy, lowrisk populations adjusted for age. On the basis of the preceding, we believe that the following trends can be identified for appropriate use of cardiac CT: Improvement in the selection of the most suitable patient populations remains important (16). Evaluation of the impact of CTA on therapeutic management is critical and is the objective of the large U.S. multicenter PROMISE (PROspective Multicenter Imaging Study for Evaluation of Chest Pain) (17) and RESCUE (Randomized Evaluation of Patients With Stable Angina Comparing Diagnostic Examinations) trials (18). In patients with intermediate stenoses on CTA, subsequent stress CTP may direct management, similar to invasive FFR (19). This is examined in the CORE320 (Combined Coronary Atherosclerosis and Myocardial Perfusion Evaluation Using 320 Detector Row Computed Tomography) trial (20). The recently described concept of CT-FFR is interesting, but incompletely understood, and further evaluation will be important to define its potential clinical role (21). Lastly, although feasible and intriguing, current data are not sufficient to support clinical use of CTDE scar imaging in the diagnostic work-up of patients with suspected CAD. Coronary CTA has developed into a valuable diagnostic option for certain symptomatic patient populations. CTP and perhaps CTDE will likely expand CTA’s application, but further evaluation of their impact on therapeutic decision making is necessary, optimally in trials with clinical endpoints. requests and correspondence: Prof. Paul Schoenhagen, Cleveland Clinic, Imaging Institute and Heart and Vascular Institute, Cardiovascular Imaging, Desk J1-4, 9500 Euclid Avenue, Cleveland, Ohio 44195. E-mail: [email protected].
Reprint
REFERENCES
1. Bettencourt N, Ferreira ND, Leite D, et al. CAD detection in patients with
intermediate-high pre-test probability: low-dose CT delayed enhancement
detects ischemic myocardial scar with moderate accuracy but does not
1073
1074
Schoenhagen and Dewey Editorial Comment
improve performance of a stress-rest CT perfusion protocol. J Am Coll Cardiol Img 2013;6:1062–71. 2. Bettencourt N, Chiribiri A, Schuster A, et al. Direct comparison of cardiac magnetic resonance and multidetector computed tomography stress-rest perfusion imaging for detection of coronary artery disease. J Am Coll Cardiol 2013;61:1099–107. 3. Bettencourt N, Chiribiri A, Schuster A, et al. Cardiac magnetic resonance myocardial perfusion imaging for detection of functionally significant obstructive coronary artery disease: a prospective study. Int J Cardiol 2012 Oct 24 [E-pub ahead of print]. 4. Schuetz GM, Zacharopoulou NM, Schlattmann P, Dewey M. Metaanalysis: noninvasive coronary angiography using computed tomography versus magnetic resonance imaging. Ann Intern Med 2010;152:167–77. 5. Schlattmann P, Schuetz GM, Dewey M. Influence of coronary artery disease prevalence on predictive values of coronary CT angiography: a metaregression analysis. Eur Radiol 2011; 21:1904–13. 6. Hulten EA, Carbonaro S, Petrillo SP, Mitchell JD, Villines TC. Prognostic value of cardiac computed tomography angiography: a systematic review and meta-analysis. J Am Coll Cardiol 2011;57:1237–47. 7. Hulten E, Pickett C, Bittencourt MS, et al. Outcomes after coronary computed tomography angiography in the emergency department: a systematic review and meta-analysis of randomized, controlled trials. J Am Coll Cardiol 2013;61:880–92. 8. Arbab-Zadeh A, Miller JM, Rochitte CE, et al. Diagnostic accuracy of computed tomography coronary angiography according to pre-test probability of coronary artery disease and severity of coronary arterial calcification. The CORE-64 International
JACC: CARDIOVASCULAR IMAGING, VOL. 6, NO. 10, 2013 OCTOBER 2013:1072–4
(Coronary Artery Evaluation Using 64-Row Multidetector Computed Tomography Angiography) International Multicenter Study. J Am Coll Cardiol 2012;59:379–87. 9. Nissen SE. Coronary computed tomography angiography. The challenge of coronary calcium. J Am Coll Cardiol 2012;59:388–9. 10. Hamon M, Fau G, Née G, Ehtisham J, Morello R, Hamon M. Meta-analysis of the diagnostic performance of stress perfusion cardiovascular magnetic resonance for detection of coronary artery disease. J Cardiovasc Magn Reson 2010;12:29. 11. Rocha-Filho JA, Blankstein R, Shturman LD, et al. Incremental value of adenosine-induced stress myocardial perfusion imaging with dual-source CT at cardiac CT angiography. Radiology 2010;254:410–9. 12. Tashakkor AY, Nicolaou S, Leipsic J, Mancini GB. The emerging role of cardiac computed tomography for the assessment of coronary perfusion: a systematic review and meta-analysis. Can J Cardiol 2012;28:413–22. 13. Rief M, Zimmermann E, Stenzel F, et al. CT angiography and myocardial CT perfusion in patient with coronary stents: prospective intraindividual comparison with conventional coronary angiography. J Am Coll Cardiol 2013 Jun 14 [E-pub ahead of print]. 14. Kwon DH, Halley CM, Carrigan TP, et al. Extent of left ventricular scar predicts outcomes in ischemic cardiomyopathy patients with significantly reduced systolic function: a delayed hyperenhancement cardiac magnetic resonance study. J Am Coll Cardiol Img 2009;2:34–44. 15. Bamberg F, Sommer WH, Hoffmann V, et al. Meta-analysis and systematic review of the long-term predictive value of assessment of coronary atherosclerosis by contrastenhanced coronary computed
tomography angiography. J Am Coll Cardiol 2011;57:2426–36. 16. Schuetz GM, Schlattmann P, Achenbach S, et al. Individual patient data meta-analysis for the clinical assessment of coronary computed tomography angiography: protocol of the Collaborative Meta-Analysis of Cardiac CT (CoMe-CCT). Syst Rev 2013;2:13. 17. PROMISE (PROspective Multicenter Imaging Study for Evaluation of Chest Pain). Available at: http://www.clinical trials.gov/ct2/show/NCT01174550? term¼NCT01174550. Accessed August 13, 2013. 18. RESCUE trials (Randomized Evaluation of Patients With Stable Angina Comparing Diagnostic Examinations). Available at: http://www.clinicaltrials. gov/ct2/show/NCT01262625?term¼ NCT01262625. Accessed August 13, 2013. 19. De Bruyne B, Pijls NH, Kalesan B, et al. Fractional flow reserve-guided PCI versus medical therapy in stable coronary disease. N Engl J Med 2012; 367:991–1001. 20. Vavere AL, Simon GG, George RT, et al. Diagnostic performance of combined noninvasive coronary angiography and myocardial perfusion imaging using 320 row detector computed tomography: design and implementation of the CORE320 multicenter, multinational diagnostic study. J Cardiovasc Comput Tomogr 2011;5:370–81. 21. Min JK, Leipsic J, Pencina MJ, et al. Diagnostic accuracy of fractional flow reserve from anatomic CT angiography. JAMA 2012;308:1237–45.
Key Words: CMR - delayed enhancement - MDCT tomography.
