Download Abstract Cardiac muscle is composed of a latticework of individual

Abstract
Cardiac muscle is composed of a latticework of individual fibers. Myocardial infarctions can alter the cardiac fiber structure tremendously. Due
to this change in fiber structure, the action potential of the heart is conducted to other places than it would in a healthy heart. The change in
fiber structure also causes the action potential to reach different places of
the heart at different times. This will cause a decreased function of the
heart. Increased knowledge of the cardiac fiber structure will lead to a
better understanding of the electrical conduction through the fibers. This
may help the diagnoses of heart problems in the future.
An imaging cryomicrotome is used to section an entire dog heart, perpendicularly to the longest axis, into slices of 40 µm. After each slice, a
high resolution photo is taken of the remaining bulk. This results in stacks
of high quality images of the entire structure of the heart. By taking photos with the appropriate excitation and emission filters, the cardiac fiber
structure is made visible. The goal of this thesis is to research whether
the contrast between the cardiac fibers can be increased. An increased
amount of contrast will allow various measurements to be done on the
fibers. Al processes done on the data are programmed in an open source
programming environment called Lazarus.
Prior to measurements on the cardiac fiber structure, it is desired to enhance the contrast between the individual fibers of the unprocessed data.
In this thesis, a technique is illustrated to increase the amount of contrast
between the individual fibers. The technique uses the eigenvalue ratio’s
of the Hessian matrix. The eigenvalues are used to enhance certain structures in the images. The contrast between the cardiac fibers is increased
by enhancing plate-like structures in the images.
To research the change of the individual cardiac fibers it is desired to
only maintain large fibers. A technique is illustrated in this thesis which
allows the separation of large fibers from the rest of the image. Another
technique is illustrated which allows the segmentation of a single fiber from
the data. This is desired for future studies to compare the fiber directions
of a healthy and an infarcted heart. In the final chapter of this thesis a
small study is done on this subject.