2-DIMENSIONAL DEFORMATION ANALYSIS OF HUMAN LEFT-VENTRICLE DURING EJECTION PERIOD USING MAGNETIC-RESONANCE TAGGING TECHNIQUE

The two-dimensional deformations of human left ventricles (Subjects we re four normal volunteers and a patient with a hypertrophic cardiomyop athy) during the ejection period were investigated using the magnetic resonance tagging technique. The displacements were measured by tracki ng the intersections of tagged stripes formed within the left ventricu lar myocardial wall, and the strains were calculated from the changes of segment lengths of triangles defined by three adjoining intersectio ns. It was recognized from the results for the normal volunteers that the magnitudes of minimum principal strains were almost uniform over a ll regions (anterior, septal, posterior and lateral) of the left ventr icular wall, while the magnitudes of displacements were different from regions to regions. The magnitude of minimum principal strain in the anterior wall of the heart with the disease was smaller compared with those of the normal hearts. This study may suggest that the minimum pr incipal strain could be an alternative effective index to evaluate the cardiac contractility.