USEFULNESS OF RESPIRATORY GATED MAGNETIC-RESONANCE CORONARY ANGIOGRAPHY IN ASSESSING NARROWINGS GREATER-THAN-OR-EQUAL-TO-50-PERCENT IN DIAMETER NATIVE CORONARY-ARTERIES AND IN AORTOCORONARY BYPASS CONDUITS

Magnetic resonance coronary angiography (MRCA) is a promising method f or the assessment at proximal coronary artery stenosis. Conventional 2 -dimensional techniques require repetitive breath holds to image multi ple sections. This may lead to misregistrations if the respiratory lev el is not exactly reproduced. In the present study, MRCA was performed using a 3-dimensional approach with navigator echo-based respiratory gating. In 73 patients (55 men and 18 women) who were referred for car diac catheterization, the assessment of significant stenoses (greater than or equal to 50%) was performed in the proximal and midsegments of the coronary arteries after multiplanar reconstruction of the visuali zed coronary arteries. In addition, in 8 patients with coronary artery bypass grafts the patency of the transplants was evaluated. After wit hdrawing 8 patients from analysis because of poor image quality, steno sis evaluation was possible in 236 of 455 reviewed coronary segments ( 52%). In the other 219 cases, either the visualization of the vessel s egment was indistinct (30%) or the segment was located outside the ima ging volume (18%). In total, 28 of 43 significant coronary stenoses co uld be correctly identified (65%). Evaluation of bypass graft patency was possible in 7 patients. All 4 occluded and 13 of 15 patent grafts were correctly classified. Thus, respiratory gated MRCA is a feasable method for the assessment of hemodynamically significant coronary sten oses and bypass graft potency. However, technical improvements are man datory to improve accuracy of the method. (C) 1997 by Excerpta Medica, Inc.