Research On Myocardium Deformation And Strain With Tagged MRI

The Magnetic Resonance Imaging( MRI), due to its special imaging mechanism, is an effective imaging method for diagnosis of cardiovascular disease and examining cardiac functions in a noninvasive manner. However, in compared to MRI, the cardiac tagged MRI may be capable of obtaing much more information of myocardium motion and thus widely used in the heart research in the world.Based on analysis of the current myocardium deformation model a novel mathematical model for computing the myocardium deformation was established in which the NN was used to fit the local myocardial displacement field and the motion of material points in heart was calculated by Newton interactive computation. Moreover, an auto-adjusted NN structure and error control technics were introduced into the model, the precision of deformation computation had been enhanced therewith. That the model was characterized by simplicity of agorithm and precision of computation was vindicated by series of tests.Since the extent and severity of myocardium disorder and sickness could be quantified by the research of myocardium strain, diagnosis of cardiac diseases in clinic would be more visual, and up to scientific in theory. On the foundation of studies on the movement of material points techniques of biomec, strain tensor, nonlinear interpolation and smoothing were used to compute the Green strain and Von-Mises strain and the results were represented graphically.In our study, all intersection points of tag lines were specified with a code number. A digital simulator for left ventricle in place of heart was designed, which proved to be capable of accurately simulate the forward and backward motions of the material points, and the results were given in numerical values and graphics.All experimental data in this thesis were from the simulator.