Abstract
Torsion movement of the left ventricle has significance in ventricle contraction and dilation. In this study, we propose methods of analyzing torsion movement of whole body and local region of left ventricle using three-dimensional images of MR Phase-contrast method. The method calculates torsion angle from average angular velocity of central axis by determining central axis from velocity field and torsion ratio from relative velocity of cross sections. In addition, we propose a method, which has no need for determining central axis, by calculating time variation of principal strain. Results showed maximum value of torsion ratio of endocardium between ventricular apex and base in the end of contraction. In addition, the result showed that torsion between cross images in the beginning of contraction and dilation is large and torsion within cross image is large in the end of contraction and dilation.
