Two-Dimensional Deformation Analysis of Human Left Ventricle during Ejection Period Using Magnetic Resonance Tagging Technique.

The two-dimensional deformations of human left ventricles(Subjects were four normal volunteers and a patient with a hypertrophic cardiomyopathy)during the ejection period were investigated using the magnetic resonance tagging technique. The displacements were measured by tracking the intersections of tagged stripes formed within the left ventricular myocardial wall, and the strains were calculated from the changes of segment lengths of triangles defined by three adjoining intersections. It was recognized from the results for the normal volunteers that the magnitudes of minimum principal strains were almost uniform over all regions(anterior, septal, posterior and lateral)of the left ventricular 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 principal strain could be an alternative effective index to evaluate the cardiac contractility.