During conventional x-ray coronary angiography, multiple projections of the
coronary arteries are acquired to define coronary anatomy precisely. Due t
o time constraints, coronary magnetic resonance angiography (MRA) usually p
rovides only one or two views of the major coronary vessels. A coronary MRA
approach that allowed for reconstruction of arbitrary isotropic orientatio
ns might therefore be desirable. The purpose of the study was to develop a
three-dimensional (3D) coronary MRA technique with isotropic image resoluti
on in a relatively short scanning time that allows for reconstruction of ar
bitrary views of the coronary arteries without constraints given by anisotr
opic voxel size. Eight healthy adult subjects were examined using a real-ti
me navigator-gated and corrected free-breathing interleaved echoplanar (TFE
-EPI) 3D-MRA sequence. Two 3D datasets were acquired for the left and right
coronary systems in each subject, one with anisotropic (1.0 x 1.5 x 3.0 mm
, 10 slices) and one with "near" isotropic (1.0 x 1.5 x 1.0 mm, 30 slices)
image resolution. All other imaging parameters were maintained. In all case
s, the entire left main (LM) and extensive portions of the left anterior de
scending (LAD) and the right coronary artery (RCA) were visualized. Objecti
ve assessment of coronary vessel sharpness was similar (41% +/- 5% vs. 42%
+/- 5%; P = NS) between in-plane and through-plane views with "isotropic" v
oxel size but differed (32% +/- 7% vs. 23% +/- 4%; P < 0.001) with nonisotr
opic voxel size. In reconstructed views oriented in the through-plane direc
tion, the vessel border was 86% more defined (P < 0.01) for isotropic compa
red with anisotropic images. A smaller (30%; P < 0.001) improvement was see
n for in-plane reconstructions. Vessel diameter measurements were view inde
pendent (2.81 +/- 0.45 mm vs. 2.66 +/- 0.52 mm; P = NS) for isotropic, but
differed (2.71 +/- 0.51 mm vs. 3.30 +/- 0.38 mm: P < 0.001) between anisotr
opic views. Average scanning time was 2:31 +/- 0:57 minutes for anisotropic
and 7:11 +/- 3:02 minutes for isotropic image resolution (P < 0.001). We p
resent a new approach for "near" isotropic 3D coronary artery imaging, whic
h allows for reconstruction of arbitrary views of the coronary arteries. Th
e good delineation of the coronary arteries in all views suggests that isot
ropic 3D coronary MRA might be a preferred technique for the assessment of
coronary disease, although at the expense of prolonged scan times. Comparat
ive studies with conventional x-ray angiography are needed to investigate t
he clinical utility of the isotropic strategy. (C) 2000 Wiley-Liss, Inc.