RESPIRATORY MOTION OF THE HEART - KINEMATICS AND THE IMPLICATIONS FORTHE SPATIAL-RESOLUTION IN CORONARY IMAGING

Respiratory motion is a major limiting factor in improving image resol ution and signal-to-noise ratio in MR coronary imaging. In this work t he effects of respiration on the cardiac position were studied quantit ively by imaging the heart during diastole at various positions of tid al respiration with a breath-hold segmented fast gradient echo techniq ue. It was found that during tidal breathing the movement of the heart due to respiration is dominated by superior-inferior (SI) motion, whi ch is linearly related to the SI motion of the diaphragm. The motion o f the heart due to respiration is approximately a global translation. These results provide motivation for employing adaptive motion correct ion techniques to reduce image blurring in nonbreath-hold coronary MR imaging.