Abstract
Quantitative assessment of skin chromophores in a non-invasive fashion is often desirable. Especially pixel wise assessment of blood volume and blood oxygenation is beneficial for improved diagnostics. We utilized a multi-spectral imaging system for acquiring diffuse reflectance images of healthy volunteers' lower forearm. Ischemia and reactive hyperemia was introduced by occluding the upper arm with a pressure cuff for 5min with 180mmHg. Multi-spectral images were taken every 30s, before, during and after occlusion. Image reconstruction for blood volume and blood oxygenation was performed, using a two layered skin model. As the images were taken in a non-contact way, strong artifacts related to the shape (curvature) of the arms were observed, making reconstruction of optical / physiological parameters highly inaccurate. We developed a curvature correction method, which is based on extracting the curvature directly from the intensity images acquired and does not require any additional measures on the object imaged. The effectiveness of the algorithm was demonstrated, on reconstruction results of blood volume and blood oxygenation for in vivo data during occlusion of the arm. Pixel wise assessment of blood volume and blood oxygenation was made possible over the entire image area and comparison of occlusion effects between veins and surrounding skin was performed. Induced ischemia during occlusion and reactive hyperemia afterwards was observed and quantitatively assessed. Furthermore, the influence of epidermal thickness on reconstruction results was evaluated and the exact knowledge of this parameter for fully quantitative assessment was pointed out.
Original language | English (US) |
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Title of host publication | Optics InfoBase Conference Papers |
Publisher | Optical Society of America |
ISBN (Print) | 9780819476432 |
State | Published - 2009 |
Externally published | Yes |
Event | European Conference on Biomedical Optics, ECBO 2009 - Munich, Germany Duration: Jun 14 2009 → Jun 18 2009 |
Other
Other | European Conference on Biomedical Optics, ECBO 2009 |
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Country | Germany |
City | Munich |
Period | 6/14/09 → 6/18/09 |
Keywords
- Blood oxygenation
- Curvature correction
- Multi-spectral imaging
- Occlusion
- Quantitative skin imaging
ASJC Scopus subject areas
- Instrumentation
- Atomic and Molecular Physics, and Optics