Image processing methods to study the living hearing organ
Author: Tiedemann, Miriam von
Date: 2009-04-03
Location: Öronklinikens föreläsningssal (Byggnad A6:02), Karolinska Universitetssjukhuset, Solna
Time: 10.00
Department: Institutionen för klinisk neurovetenskap / Department of Clinical Neuroscience
View/ Open:
Thesis (2.250Mb)
Abstract
In this thesis we are developing image processing methods allowing one to probe the structure and function of the mammalian hearing organ, an intricate cellular assembly with a highly specialized three-dimensional organization. Confocal as well as electron microscopy was used for image acquisition.
Three-dimensional confocal imaging is hampered by noise and blur, and this is even more significant when working with deep biological imaging, such as our temporal bone preparation of the guinea pig cochlea. Blur is not only caused by the optical properties of the microscope, but by the scattering of light and distortions caused by the sample itself. Deconvolution is widely used in image processing to reverse these effects. If the system’s point-spread function (PSF) is known, a deconvolution can be performed leading to increased image resolution. The idea of getting all the information about the PSF and deconvolution from the image itself is explored in this thesis. A set of tools were developed that screens the images for structures that can be used as PSF estimates. Using the extracted structures, a PSF model for deconvolution was designed, resulting in a significant improvement in deconvolutions of images acquired from the inner ear.
To study functionally relevant movements inside the hearing organ, a wavelet-based three- dimensional brightness-adjusted optical flow algorithm was designed. Numerical experiments show that the algorithm allows motion detection with less than 10% magnitude error over the range from 0.5 – 5 pixels under conditions of noise more severe than that typically found in real experiments. The angular error was less than 10° for the same range of motions. Accurate quantification of motion and deformation patterns in the hearing organ is therefore possible. The algorithm was applied to three-dimensional image sequences showing the sound-evoked motion of cochlear sensory cells. Motion directed perpendicular and parallel to the surface of the hearing organ were robust and displayed a linear relationship to each other, suggesting that they are governed by passive cellular properties such as stiffness, mass and damping. In contrast, components directed away from the center of the spiral-shaped cochlea showed much higher variability, and these components may be more tightly linked to the active, force-generating property of the outer hair cells.
Outer hair cells are unique because of their capacity for high-frequency force generation, which requires specialized connections between molecular motors and the cell skeleton. Using electron tomography and three-dimensional reconstruction, we examined one such connecting structure, the “pillars“, which links the plasma membrane to the cell skeleton. Individual pillars show structural variability, which may have functional relevance. However, tissue processing and imperfect imaging conditions may cause a part of the variability.
Information gained from these studies will be useful to develop a more detailed understanding of the three dimensional micromechanics of the cochlea, and to test existing models describing the mechanical vibrations of this organ.
Three-dimensional confocal imaging is hampered by noise and blur, and this is even more significant when working with deep biological imaging, such as our temporal bone preparation of the guinea pig cochlea. Blur is not only caused by the optical properties of the microscope, but by the scattering of light and distortions caused by the sample itself. Deconvolution is widely used in image processing to reverse these effects. If the system’s point-spread function (PSF) is known, a deconvolution can be performed leading to increased image resolution. The idea of getting all the information about the PSF and deconvolution from the image itself is explored in this thesis. A set of tools were developed that screens the images for structures that can be used as PSF estimates. Using the extracted structures, a PSF model for deconvolution was designed, resulting in a significant improvement in deconvolutions of images acquired from the inner ear.
To study functionally relevant movements inside the hearing organ, a wavelet-based three- dimensional brightness-adjusted optical flow algorithm was designed. Numerical experiments show that the algorithm allows motion detection with less than 10% magnitude error over the range from 0.5 – 5 pixels under conditions of noise more severe than that typically found in real experiments. The angular error was less than 10° for the same range of motions. Accurate quantification of motion and deformation patterns in the hearing organ is therefore possible. The algorithm was applied to three-dimensional image sequences showing the sound-evoked motion of cochlear sensory cells. Motion directed perpendicular and parallel to the surface of the hearing organ were robust and displayed a linear relationship to each other, suggesting that they are governed by passive cellular properties such as stiffness, mass and damping. In contrast, components directed away from the center of the spiral-shaped cochlea showed much higher variability, and these components may be more tightly linked to the active, force-generating property of the outer hair cells.
Outer hair cells are unique because of their capacity for high-frequency force generation, which requires specialized connections between molecular motors and the cell skeleton. Using electron tomography and three-dimensional reconstruction, we examined one such connecting structure, the “pillars“, which links the plasma membrane to the cell skeleton. Individual pillars show structural variability, which may have functional relevance. However, tissue processing and imperfect imaging conditions may cause a part of the variability.
Information gained from these studies will be useful to develop a more detailed understanding of the three dimensional micromechanics of the cochlea, and to test existing models describing the mechanical vibrations of this organ.
List of papers:
I. Von Tiedemann M, Fridberger A, Ulfendahl M, Tomo I, Boutet de Monvel J (2006). Image adaptive point-spread function estimation and deconvolution for in vivo confocal microscopy. Microsc Res Tech. 69(1): 10-20
Pubmed
II. von Tiedemann M, Fridberger A, Ulfendahl M, Boutet de Monvel J (2009). A brightness-compensated three-dimensional optical flow algorithm for monitoring cochlear motion patterns. [Manuscript]
III. von Tiedemann M, Boutet de Monvel J, Fridberger A (2009). Monitoring three-dimensional dynamical processes in the cochlea. [Manuscript]
IV. Fridberger A, Von Tiedemann M, Flock A, Flock B, Ofverstedt LG, Skoglund U (2008). Three-dimensional structure of outer hair cell pillars. Acta Otolaryngol. Nov 20: 1-6. [Epub ahead of print]
Pubmed
I. Von Tiedemann M, Fridberger A, Ulfendahl M, Tomo I, Boutet de Monvel J (2006). Image adaptive point-spread function estimation and deconvolution for in vivo confocal microscopy. Microsc Res Tech. 69(1): 10-20
Pubmed
II. von Tiedemann M, Fridberger A, Ulfendahl M, Boutet de Monvel J (2009). A brightness-compensated three-dimensional optical flow algorithm for monitoring cochlear motion patterns. [Manuscript]
III. von Tiedemann M, Boutet de Monvel J, Fridberger A (2009). Monitoring three-dimensional dynamical processes in the cochlea. [Manuscript]
IV. Fridberger A, Von Tiedemann M, Flock A, Flock B, Ofverstedt LG, Skoglund U (2008). Three-dimensional structure of outer hair cell pillars. Acta Otolaryngol. Nov 20: 1-6. [Epub ahead of print]
Pubmed
Issue date: 2009-03-13
Rights:
Publication year: 2009
ISBN: 978-91-7409-371-1
Statistics
Total Visits
Views | |
---|---|
Image ...(legacy) | 684 |
Image ... | 94 |
Total Visits Per Month
September 2023 | October 2023 | November 2023 | December 2023 | January 2024 | February 2024 | March 2024 | |
---|---|---|---|---|---|---|---|
Image ... | 1 | 0 | 1 | 0 | 0 | 0 | 0 |
File Visits
Views | |
---|---|
thesis.pdf(legacy) | 357 |
thesis.pdf | 90 |
thesis.pdf.txt(legacy) | 2 |
Top country views
Views | |
---|---|
United States | 321 |
Sweden | 52 |
China | 49 |
Germany | 48 |
Russia | 18 |
Finland | 14 |
South Korea | 14 |
India | 11 |
Denmark | 9 |
United Kingdom | 7 |
Top cities views
Views | |
---|---|
Sunnyvale | 39 |
Romeo | 35 |
Beijing | 21 |
Kiez | 17 |
Seoul | 14 |
Dublin | 7 |
Ballerup | 6 |
Helsinki | 6 |
London | 6 |
Stockholm | 6 |