EFFECT OF ARTIFACTS DUE TO FLOWING BLOOD ON THE REPRODUCIBILITY OF PHASE-CONTRAST MEASUREMENTS OF MYOCARDIAL MOTION

The reproducibility of myocardial motion trajectories calculated from cine phase-contrast (PC) velocity data is reduced by artifacts due to the inconsistent motion of intracardiac blood. Spatial presaturation r educes these artifacts but requires a longer sequence TR, with a poten tially negative effect on trajectory accuracy and reproducibility. We investigated the effect of spatial presaturation on trajectory reprodu cibility. A midventricular transaxial slice was imaged in five normal volunteers, The same slice was imaged three times each with sequences using spatial presaturation or not, Because the most serious artifacts originate in the heart chambers and propagate in the phase-encoded di rection, myocardial regions that were in line with the heart chambers (in the phase-encode direction) had the highest artifact level in the scans without spatial presaturation. The reproducibility of trajectori es for regions placed in these areas (the anterior wall, septum and po sterior wall in the transaxial scans with phase encoding in the anteri or-posterior direction) improved by a factor of two when presaturation was used (P < .001). In areas that were not in line with the heart ch ambers (eg, the anterior aspect of the lateral wall in the transaxial scans), the effect of presaturation was not significant. These results correlate well with the measured reduction in artifact level. The rep roducibility of myocardial motion trajectories over large areas of the heart is improved to approximately 1 mm when presaturation is used, T herefore, use of presaturation is recommended for myocardial motion st udies using cine PC velocity data.