Meta-analysis: Noninvasive Coronary Angiography Using Computed Tomography Versus Magnetic Resonance Imaging
OBJECTIVES: Two imaging techniques, multislice computed tomography (CT) and magnetic resonance imaging (MRI), have evolved for noninvasive coronary angiography. To compare CT and MRI for ruling out clinically significant coronary artery disease (CAD) in adults with suspected or known CAD.
METHODS: MEDLINE, EMBASE, and ISI Web of Science searches from inception through 2 June 2009 and bibliographies of reviews. 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. 2 investigators independently extracted patient and study characteristics; differences were resolved by consensus.
RESULTS: 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). 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.
CONCLUSIONS: For ruling out CAD, CT is more accurate than MRI. Scanners with more than 16 rows improve sensitivity, as do slowed heart rates.
PMID: 16442907
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Paul Schoenhagen, MD on February 2nd, 2010
This meta-analysis summarizes the experience with CT and MRI for coronary imaging.
For more comments check story on http://www.theheart.org
Jacobo Kirsch, MD on February 2nd, 2010
This meta-analysis reviewed data obtained from just over 8500 patients!
Important data from this paper (not included in the abstract) is that newer CT scanners are more sensitive than older scanners, and involve less iodinated contrast agent, but higher radiation doses.
Ronen Rubinshtein, MD on February 5th, 2010
May I also remind the readers that the interpretation of coronary CTA requires visual assessment and is a matter for well trained personnel!
Beyond “evidence based” data. I personally believe that currently, the accuracy of coronary CTA still depends heavily on the “human factor” (and center volume and case mix), and not only on the number of detectors. This “factor” cannot be fully accounted for in CTA imaging meta-analysis papers, but should only encourage us to improve as readers and collaborate with other institutions to learn and teach new techniques and protocols.