DIRECTED PROXIMAL MAGNETIC-RESONANCE CORONARY ANGIOGRAPHY COMPARED WITH CONVENTIONAL CONTRAST CORONARY ANGIOGRAPHY

Magnetic resonance imaging (MRI) angiography is a noninvasive techniqu e that has been used to examine vessels of a relatively large diameter , such as cerebral arteries(1) as well as arteries of the lower extrem ity.(2) However, at the scanning speeds used so far, satisfactory MR i mages of the coronary arteries has not been obtainable due both to car diac motion, which causes a large degree of vessel displacement and th e relatively small diameter of coronary arteries.(3-5) In recent years , however, ultra high-speed scanners have been developed, so that it i s now possible to perform electrocardiography-gated scan of the corona ry arteries during breath-holding. As a result, preliminary studies of the application of MRI to coronary artery imaging have been reported. (6-8) However. because scanning time can be long in order to accomplis h gating with electrocardiography, the quality of MR images of small c oronary arteries can easily deteriorate because of body movement or ch anges in respiration. Reduction in the scanning time is therefore nece ssary both to reduce the discomfort of the patient and to improve the quality of the MR images. We have recently introduced modifications th at reduce the scanning time of MR coronary angiography, and the purpos e of this study was to assess the clinical value of MRT coronary angio graphy compared with conventional contrast coronary angiography.