In-Vivo Digital Image Correlation Studies of the Motion and Deformation of the Human Heart during Open Heart Surgery
|Tila||Julkaistu - 26 kesäkuuta 2020|
|Nimi||Tampere University Dissertations|
The difference in the values obtained from these two methods can be explained by the fact that the location of the measurements are not exactly the same, as DIC measures the top surface of the heart and the STE observes the movement and deformation from below. Also this work demonstrates that deformation of the heart can be highly anisotropic and localized, and therefore, the absolute values of strain or other quantities depend strongly on the location from where the values were obtained. DIC can provide full field deformation data to describe the anisotropy and the strains at high spatial resolution, but this data is not easy to interpret quantitatively, and is therefore not very suitable for clinical work.
Consequently, a method based on the orthogonal decomposition was used to simplify the full field deformation heat map images (acquired from the DIC analysis) to numerical values, and to reduce the quantitative strain and deformation information of the full field image into a single number using shape descriptors. The difference in the deformation data contained in any two deformation heat map images can be numerically presented as the Euclidian distance between the two shape descriptor vectors of the corresponding images. This method can be used to describe the deformation of the RV in a more comprehensive manner, to compare the deformation between the different stages of the surgery, and to study any changes that might occur during the entire operation. The method output is a single number that could be used as an index to describe the mechanical function of the heart and to indicate changes and effect of, for example, medication administered to the patient during the operation.