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| Author(s): |
Wietske Ineke Meyering
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Escola Politécnica (EP/BC) |
| Defense date: | 2002-10-14 |
| Examining board members: |
Marco Antonio Gutierrez;
Sérgio Shiguemi Furuie;
Nelson Delfino d'Ávila Mascarenhas;
Jose Carlos Teixeira de Barros Moraes;
Annie France Frere Slaets
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| Advisor: | Marco Antonio Gutierrez |
| Abstract | |
Diseases in complex organs as the heart require appropriate tools of analysis for the diagnosis, therapy and attendance of the patient. Assessment of the myocardium function, for example, to decide the more appropriate therapy, implies in ideal scenery, to visualize the dynamics of the cardiac walls and to quantify the motion and the strength of regional contraction. Fast or synchronized tomograph allows the noninvasive investigation of slices of the dynamic structure. However, really 3-dimensional information, as the volumetric variation and regional contractions are not provided by the commercial equipment mainly due to the difficulties in 3D segmentation and automatic attendance of regions. The complex deformation that occurs during the contraction and relaxation of the left ventricle (LV) has forced investigators to make major simplifying assumptions to interpret LV motion. It is usual to model the LV as having some particular shape or symmetry, such as an ellipsoid, in order to study its geometrical changes. These assumptions may not be valid for ventricles presenting ischemia or infarction. The proper quantification of the cardiac motion still remains an open and challenging research problem. The aim of this thesis is the quantification of movement and function of the left ventricle in Nuclear Medicine images, trough an automatic method, without modeling the ventricle. The method estimates the velocity vector field (or optical flow) based on aspatiotemporal-frequency approach, through Wigner-Ville and Choi-Williams distributions. The assessment of the proposed method was accomplished with synthetic images through translation and rotation movements and with a mathematical cardiac phantom, achieving the correspondent velocity vector field. The results obtained corroborated the current proposal. In addition, the experiments indicate the feasibility of employing the method in clinical applications. (AU) | |