Preliminary Results of MRI Angiography Show Reliability in Detecting CAD
NEW YORK (Reuters Health) – Stanford University researchers have developed a magnetic resonance coronary angiography (MRCA) technique that can quickly and accurately detect coronary artery disease (CAD), preliminary study results suggest.
Dr. Phillip C. Yang and associates describe their system, in which they combined a spiral high-resolution coronary artery imaging sequence with a real-time localization system, in the Journal of the American College of Cardiology for April 2. To test the clinical implementation of this strategy, they compared X-ray angiography results with those obtained using the new MRCA for 40 patients referred for cardiac catheterization.
MRCA imaged 94% of 337 segments revealed by coronary angiography. There were 41 coronary lesions seen on X-ray, for which MRCA yielded a sensitivity of 76% and specificity of 91%.
Real time scanning took 3 to 12 minutes per patient, the California-based investigators report. The total time required for high-resolution scanning ranged from 5 to 40 minutes to reach optimum image quality. An average of 10 breath-holds were required for each patient, lasting for 14 heartbeats (< 15 s). The procedure was well tolerated, the report indicates. Dr. Yang and his colleagues recognize that challenges must be overcome before MRCA is ready for routine clinical implementation. Higher signal-to-noise and contrast-to-noise ratios will be required to better visualize distal segments of the left anterior descending coronary artery and the left circumflex coronary artery, and shorter breath-holds are desirable. Efforts are already underway to increase spatial resolution. Dr. Andrew Arai, of the National Heart, Lung, and Blood Institute, agrees that “there is still a lot of work to be done.” In a journal statement, he adds that it will take time for such sophisticated techniques to be disseminated and for the medical community to develop the expertise to conduct MRCA. Still, he adds, the image quality is close to the results required for clinical use. J Am Coll Cardiol 2003;41:1134-1141.
