Multislice CT had greater sensitivity, specificity, and negative predictive value, with equivalent positive predictive value, than did MRI for angiographic diagnosis of 108 patients.
Multislice CT also had less than half the rate of noninterpretable results.
Dr. Marc Dewey of Humboldt University's Charité Medical School, Berlin, and colleagues assessed patients referred to their center for conventional coronary angiography for suspected coronary artery disease (CAD). Patients were a mean of 64 years old and in sinus rhythm (Ann. Intern. Med. 2006;145:407–15).
After undergoing conventional angiography, each patient within 1 day underwent multislice CT and MRI; readers assessed the results without knowing the results of conventional angiography or other clinical data.
Multislice CT had a sensitivity of 92%, versus 74% for MRI. For specificity, CT rendered 79%, versus MRI's 75%. Negative predictive value was 90% and 84%, respectively, and positive predictive value was 95% for both instruments. Only 7% of CT results were noninterpretable, versus 18% of those produced by MRI. However, for both machines, the only findings that reached statistical significance were sensitivity and the percentage of noninterpretable images.
These findings led the investigators to conclude that in their study, CT was superior to MRI in detecting coronary artery stenoses, and its high negative predictive value “makes it potentially useful as a diagnostic tool for ruling out coronary disease in a population with a low to intermediate pretest likelihood.”