VISUALIZATION OF THE CORONARY-ARTERIES IN 3-DIMENSIONAL RECONSTRUCTIONS USING RESPIRATORY GATED MAGNETIC-RESONANCE-IMAGING

Objective To assess the applicability of respiratory-gated magnetic re sonance coronary angiography, combined with three-dimensional image re construction, for visualizing the coronary arteries. Methods Twenty su bjects (three healthy volunteers and 17 patients without stenoses dete cted by coronary angiography) were investigated. Magnetic resonance im aging was performed in a 1.5 T scanner using ECG-triggered gradient-ec ho sequences to acquire a volume data set consisting of 24-48 contiguo us axial cross-sections of the heart (2 mm slice thickness, 1.17 mm x 1.17 mm in-plane resolution). Navigator-echo-based retrospective respi ratory gating was used to minimize respiratory motion artifacts. Three -dimensional reconstructions of the heart were rendered using surface- display techniques. The length of the visualized coronary arteries was measured in curved multiplanar reconstructions. Results In the three- dimensional reconstructions, the left main artery (LMA) and left anter ior descending artery (LADA) were visualized in 17 cases, the left cir cumflex artery (LCXA) in 15, and the right coronary artery (RCA) in 16 cases. Vessel continuity was uninterrupted in all 17 cases for the LM A, in 14 for the LADA, eight for the LCXA, and 13 for the RCA. The mea n lengths of the visualized vessels were 14 +/- 7 mm for the LMA, 65 /- 13 mm for the LADA, 45 +/- 16 mm for the LCXA, and 37 +/- 26 mm for the RCA. Reasons for impaired visibility of the LCXA and RCA were poo r image quality due to there being a low contrast:noise ratio, motion artifacts, and incomplete coverage by the imaging volume. Conclusions Navigator-echo-based magnetic resonance imaging is a promising techniq ue for investigating the coronary arteries. Acquisition of a volume da ta set permits three-dimensional displays of the coronary vessels. (C) Rapid Science Publishers ISSN 0954-6928.