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Meta-analysis: Noninvasive Coronary Angiography Using Computed Tomography Versus Magnetic Resonance Imaging

Georg M. Schuetz, MS; Niki Maria Zacharopoulou, MD; Peter Schlattmann, MD, PhD; and Marc Dewey, MD, PhD
[+] Article and Author Information

From Charité Medical School, Berlin, Germany.


Acknowledgment: The authors thank all contacted authors who provided extra data for this meta-analysis.

Potential Conflicts of Interest: Disclosures can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=M09-1663.

Requests for Single Reprints: Marc Dewey, MD, PhD, Department of Radiology, Charité Medical School, Humboldt-Universität zu Berlin, Freie Universität Berlin, Charitéplatz 1, 10117 Berlin, Germany; e-mail, marc.dewey@charite.de.

Current Author Addresses: Mr. Schuetz and Drs. Zacharopoulou and Dewey: Department of Radiology, Charité Medical School, Humboldt-Universität zu Berlin, Freie Universität Berlin, Charitéplatz 1, 10117 Berlin, Germany.

Dr. Schlattmann: Department of Biostatistics and Clinical Epidemiology, Charité Medical School, Humboldt-Universität zu Berlin, Charitéplatz 1, 10117 Berlin, Germany.

Author Contributions: Conception and design: G.M. Schuetz, M. Dewey.

Analysis and interpretation of the data: G.M. Schuetz, N.M. Zacharopoulou, P. Schlattmann, M. Dewey.

Drafting of the article: G.M. Schuetz, P. Schlattmann, M. Dewey.

Critical revision of the article for important intellectual content: N.M. Zacharopoulou.

Final approval of the article: G.M. Schuetz, N.M. Zacharopoulou, P. Schlattmann, M. Dewey.

Statistical expertise: P. Schlattmann.

Administrative, technical, or logistic support: M. Dewey.

Collection and assembly of data: G.M. Schuetz, N.M. Zacharopoulou.


Ann Intern Med. 2010;152(3):167-177. doi:10.7326/0003-4819-152-3-201002020-00008
Text Size: A A A

Background: Two imaging techniques, multislice computed tomography (CT) and magnetic resonance imaging (MRI), have evolved for noninvasive coronary angiography.

Purpose: To compare CT and MRI for ruling out clinically significant coronary artery disease (CAD) in adults with suspected or known CAD.

Data Sources: MEDLINE, EMBASE, and ISI Web of Science searches from inception through 2 June 2009 and bibliographies of reviews.

Study Selection: Prospective English- or German-language studies that compared CT or MRI with conventional coronary angiography in all patients and included sufficient data for compilation of 2 × 2 tables.

Data Extraction: 2 investigators independently extracted patient and study characteristics; differences were resolved by consensus.

Data Synthesis: 89 and 20 studies (comprising 7516 and 989 patients) assessed CT and MRI, respectively. Bivariate analysis of data yielded a mean sensitivity and specificity of 97.2% (95% CI, 96.2% to 98.0%) and 87.4% (CI, 84.5% to 89.8%) for CT and 87.1% (CI, 83.0% to 90.3%) and 70.3% (CI, 58.8% to 79.7%) for MRI. In studies that included only patients with suspected CAD, sensitivity and specificity of CT were 97.6% (CI, 96.1% to 98.5%) and 89.2% (CI, 86.0% to 91.8%). Covariate analysis yielded a significantly higher sensitivity for CT scanners with more than 16 rows (98.1% [CI, 97.0% to 99.0%]; P < 0.050) than for older-generation scanners (95.6% [CI, 94.0% to 97.0%]). Heart rates less than 60 beats/min during CT yielded significantly better values for sensitivity than did higher heart rates (P < 0.001).

Limitations: Few studies investigated coronary angiography with MRI. Only 5 studies were direct head-to-head comparisons of CT and MRI. Covariate analyses explained only part of the observed heterogeneity.

Conclusion: For ruling out CAD, CT is more accurate than MRI. Scanners with more than 16 rows improve sensitivity, as do slowed heart rates.

Primary Funding Source: None.

Figures

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Appendix Figure 1.
Literature search and selection.

CT = computed tomography; MRA = magnetic resonance angiography; MRI = magnetic resonance imaging.

* 1 study (114) by another meta-analysis, 3 studies (115–117), and 1 study (120) suggested by an expert reader.

† 2 studies (118, 119) and 1 abstract (121) suggested by an expert reader.

‡ Overlap was either explicitly stated in the studies or could not be excluded by contacting the corresponding authors.

§ An attempt was made to contact all corresponding authors, but no further information was available.

∥ Studies in which coronary artery plaque assessment or accuracy in percentage of diameter quantification was the primary objective also are included.

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Figure 1.
Reviewer judgments of methodological quality of included studies, according to the Quality Assessment of Diagnostic Accuracy Studies tool.

Methodological quality was generally moderate to poor. Both CT and MRI studies scored poorly on disease progression bias, partial verification bias, and reference standard details. Only 1 CT study (98) explicitly mentioned that additional clinical data were offered to readers. Only 2 CT studies (31, 120) and 2 MRI studies (31, 119) fulfilled all criteria other than the clinical data item. CT = computed tomography; MRI = magnetic resonance imaging. Top. Judgments of CT studies. Bottom. Judgments of MRI studies.

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Figure 2.
Summary ROC curves for CT and MRI.

Curves include a summary operating point for sensitivity and specificity on the curve and a 95% confidence contour ellipsoid. AUC = area under the curve; CT = computed tomography; MRI = magnetic resonance imaging; ROC = receiver-operating characteristic.

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Appendix Figure 2.
Funnel plots for included studies.

Top. Computed tomography studies. Bottom. Magnetic resonance imaging studies.

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Appendix Figure 3.
Included studies, by year of publication (2003 to 2009).

More than 50% of included CT studies were published during the past 2 years (2007 and 2008). CT = computed tomography; MRI = magnetic resonance imaging.

* We performed database searches through 2 June 2009.

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Figure 3.
Probabilities of coronary artery disease after multislice CT and MRI.

To identify the implications of our results for clinical decision making, we calculated the posttest probability after negative and positive findings on multislice CT and MRI for populations with different prevalences (pretest probabilities) of coronary artery disease, according to the Bayes theorem, by using the sensitivity and specificity of CT studies that included patients with suspected coronary artery disease (Table). The plot shows that CT coronary angiography is very accurate in ruling out disease over a wide range of pretest probabilities of coronary artery disease (20% to 80%), as shown by the very low posttest probability (<10%) of coronary artery disease after a negative CT result. CT = computed tomography; MRI = magnetic resonance angiography.

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Appendix Figure 4.
Likelihood ratio scattergram for computed tomography.

The scattergram is based on our findings for the studies that included patients with suspected coronary artery disease (Table). The likelihood ratio profile shows that computed tomography is a potent tool for ruling out coronary artery disease in this patient population.

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References

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There is more to Coronary Artery Disease than Epicardial Anatomy
Posted on March 1, 2010
Eike Nagel
King's College London, Chair of Cardiovascular Imaging
Conflict of Interest: None Declared

To the Editor: We read with great interest the meta-analysis by Schuetz et al (1) which aims to compare the diagnostic accuracy of Computed Tomography (CT) and Magnetic Resonance (MR) Coronary Angiography against invasive X-ray coronary angiography. The main result of this meta- analysis was that CT coronary angiography was more accurate than MR coronary angiography.

Despite the careful study design this report is, in our view, potentially misleading. We completely agree with the results from the authors, that CT is the more accurate of the two tests for non-invasive coronary angiography. This is generally accepted within the field which is why, as noted by the authors, there are relatively few publications in recent years on MR coronary angiography. However, while the study title correctly refers to "non-invasive coronary angiography" by CT and MR, the remainder of the text and its conclusions refer less specifically only to "CT and MRI". This generalization opens the study to potential misinterpretation.

1.) The main strength of cardiac MR and its main clinical role in CAD have become its ability to provide functional assessment of coronary stenosis by means of pharmacological stress imaging rather than providing purely anatomic information. MR has been shown in single and multi-centre studies to be at least as accurate as the current clinical reference test, Single Photon Emission Computed Tomography in detecting flow-limiting coronary disease (2).

2.) An accumulating body of evidence underscores the importance of functional assessment of stenosis severity. Patients without detectable ischemia on non-invasive imaging, including MR, have a very good prognosis, whilst the presence of detectable myocardial ischemia confers a significantly worse prognosis (3). In addition, in patients with anatomically moderate disease, there is a prognostic benefit when percutaneous revascularization is targeted only at functionally significant lesions (4). Given that anatomic assessment of the severity of a coronary artery stenosis has been repeatedly shown to correlate poorly with the hemodynamic effects (5), coronary angiography provides only some of the information which is important in CAD. It is therefore questionable to describe the coronary stenoses detected by angiography as "clinically significant". The predominant view within cardiology, which bases treatment on the presence of coronary stenoses, is beginning to be replaced with an understanding that functional significance needs to be the clinical reference. CT is currently not able to provide such functional assessment.

Thus, referring to MR throughout this manuscript solely with reference to coronary MR angiography, and not commenting on the functional information provided by either test seems misleading. Equally, to conclude in the abstract that "For ruling out CAD, CT is more accurate than MRI" and in the editorial comment that "Computed tomographic angiography may be a better noninvasive test than MRI for ruling out coronary artery disease" seems an unjustified simplification that ignores the emerging broader role of CMR in the management of CAD. It is of great concern that this study has already triggered unqualified media responses such as "CT More Accurate Than MRI for Ruling out Coronary Artery Disease" in Heartwire CME, 2010-02-05 and is likely to continue to misinform the less initiated public.

References

1. Schuetz GM, Zacharopoulou NM, Schlattmann P, Dewey M. Meta- analysis: noninvasive coronary angiography using computed tomography versus magnetic resonance imaging. Ann Intern Med. 2010;152(3):167-77.

2. Schwitter J, Wacker CM, van Rossum AC, et al. MR-IMPACT: comparison of perfusion-cardiac magnetic resonance with single-photon emission computed tomography for the detection of coronary artery disease in a multicentre, multivendor, randomized trial. European Heart Journal. 2008;29(4):480-9.

3. Jahnke C, Nagel E, Gebker R, et al. Prognostic Value of Cardiac Magnetic Resonance Stress Tests: Adenosine Stress Perfusion and Dobutamine Stress Wall Motion Imaging. Circulation. 2007;115(13):1769-1776. 4. Tonino PA, De Bruyne B, Pijls NH, et al. Fractional flow reserve versus angiography for guiding percutaneous coronary intervention. N Engl J Med. 2009;360(3):213-24.

5. White CW, Wright CB, Doty DB, et al. Does visual interpretation of the coronary arteriogram predict the physiologic importance of a coronary stenosis? N Engl J Med. 1984;310(13):819-24.

Conflict of Interest:

Grant Support received from Philips Healthcare and Bayer Schering Pharma

Re:There is more to Coronary Artery Disease than Epicardial Anatomy
Posted on March 30, 2010
Marc Dewey
Charite, Medical School Dept of Radiology, Humboldt-Universitat zu Berlin, Freie Univ., Berlin, Ger.
Conflict of Interest: None Declared

I agree with Nagel et al. that "preoccupation with coronary lumenology"(1) prevents one from grasping the whole picture of coronary artery disease and that functional tests assessing either perfusion or wall motion during rest and stress enable the best hemodynamic evaluation of coronary artery stenosis (2). Assessment of myocardial perfusion, e.g., using magnetic resonance imaging (MRI) or single-photon emission computed tomography, plays a pivotal role in the clinical management of patients with known coronary artery disease since revascularization is most beneficial in patients with more severe ischemia (3).

However, our meta-analysis was designed to analyze noninvasive coronary angiography using computed tomography (CT) versus MRI with conventional coronary angiography as the reference standard for detection of stenosis. In this setting, we showed that coronary CT provides a more sensitive and specific assessment of the coronary arteries than MR angiography (4). Interestingly, we found a per-patient sensitivity for coronary CT angiography of 97.2% (95% confidence intervals, 96.2-98.0%), which was significantly higher than that reported for myocardial perfusion MRI in a meta-analysis by Nandalur (91%; 95% confidence intervals, 88- 94.0%) (2). Notably, prevalence of coronary artery disease was comparable in both meta-analyses at 54.7% (4) and 57.4% (2), respectively. Thus, published evidence suggests that coronary CT angiography is not only more accurate than coronary MR angiography but also more accurate than perfusion MRI in ruling out coronary artery disease.

It is important to note that recent studies show the potential of state-of-the-art multislice CT scanners to perform stress and rest myocardial perfusion imaging as well (5-7), which may be an important advance of this modality towards a more comprehensive cardiac imaging test. Nevertheless, because of its unique advantage of not requiring radiation exposure, MRI is the most promising cardiac imaging test and is also more versatile, allowing assessment of myocardial infarction, fibrosis, function, and metabolism. Thus, if the diagnostic performance of MRI in coronary angiography can be further improved, this test may become the most important imaging tool for noninvasively and comprehensively assessing patients with suspected coronary artery disease. Currently, cardiac CT should be considered the foremost noninvasive test for detecting and ruling out coronary artery stenosis in selected patient populations.

References

1. Topol EJ, Nissen SE. Our preoccupation with coronary luminology. The dissociation between clinical and angiographic findings in ischemic heart disease. Circulation. 1995;92(8):2333-42.

2. Nandalur KR, Dwamena BA, Choudhri AF, Nandalur MR, Carlos RC. Diagnostic performance of stress cardiac magnetic resonance imaging in the detection of coronary artery disease: a meta-analysis. J Am Coll Cardiol. 2007;50(14):1343-53.

3. Shaw LJ, Berman DS, Maron DJ, Mancini GB, Hayes SW, Hartigan PM, et al. Optimal medical therapy with or without percutaneous coronary intervention to reduce ischemic burden: results from the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial nuclear substudy. Circulation. 2008;117(10):1283-91.

4. Schuetz GM, Zacharopoulou NM, Schlattmann P, Dewey M. Meta- analysis: Noninvasive Coronary Angiography Using Computed Tomography versus Magnetic Resonance Imaging. Ann Intern Med. 2010;152(3):167-177.

5. Rocha-Filho JA, Blankstein R, Shturman LD, Bezerra HG, Okada DR, Rogers IS, et al. Incremental value of adenosine-induced stress myocardial perfusion imaging with dual-source CT at cardiac CT angiography. Radiology. 2010;254(2):410-9.

6. de Roos A. Myocardial perfusion imaging with multidetector CT: beyond lumenography. Radiology. 2010;254(2):321-3.

7. George RT, Arbab-Zadeh A, Miller JM, Kitagawa K, Chang HJ, Bluemke DA, et al. Adenosine stress 64- and 256-row detector computed tomography angiography and perfusion imaging: a pilot study evaluating the transmural extent of perfusion abnormalities to predict atherosclerosis causing myocardial ischemia. Circ Cardiovasc Imaging. 2009;2(3):174-82.

Conflict of Interest:

None declared

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