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Visible, Hyperspectral Imaging Evaluating the Cutaneous Response to Ultraviolet Radiation
Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
Linköpings universitet, Institutionen för biomedicin och kirurgi, Avdelningen för dermatologi och venereologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Medicincentrum, Hudkliniken US.
Linköpings universitet, Institutionen för medicinsk teknik, Biomedicinsk instrumentteknik. Linköpings universitet, Tekniska högskolan.
2007 (Engelska)Ingår i: Imaging, Manipulation, and Analysis of Biomolecules, Cells, and Tissues V / [ed] Daniel L. Farkas; Robert C. Leif; Dan V. Nicolau, SPIE - International Society for Optical Engineering, 2007, s. 644103-1-644103-12Konferensbidrag, Publicerat paper (Övrigt vetenskapligt)
Abstract [en]

In vivo diagnostics of skin diseases as well as understanding of the skin biology constitute a field demanding characterization of physiological and anatomical parameters. Biomedical optics has been successfully used, to qualitatively and quantitatively estimate the microcirculatory conditions of superficial skin. Capillaroscopy, laser Doppler techniques and spectroscopy, all elucidate different aspects of microcirculation, e.g. capillary anatomy and distribution, tissue perfusion and hemoglobin oxygenation. We demonstrate the use of a diffuse reflectance hyperspectral imaging system for spatial and temporal characterization of tissue oxygenation, important to skin viability. The system comprises: light source, liquid crystal tunable filter, camera objective, CCD camera, and the decomposition of the spectral signature into relative amounts of oxy- and deoxygenized hemoglobin as well as melanin in every pixel resulting in tissue chromophore images. To validate the system, we used a phototesting model, creating a graded inflammatory response of a known geometry, in order to evaluate the ability to register spatially resolved reflectance spectra. The obtained results demonstrate the possibility to describe the UV inflammatory response by calculating the change in tissue oxygen level, intimately connected to a tissue's metabolism. Preliminary results on the estimation of melanin content are also presented.

Ort, förlag, år, upplaga, sidor
SPIE - International Society for Optical Engineering, 2007. s. 644103-1-644103-12
Serie
Proceedings of SPIE (Progress in biomedical optics and imaging), ISSN 1605-7422 ; 6441
Nyckelord [en]
Hyperspectral imaging, Ultraviolet provocation, Erythema, Hemoglobin, CCD camera, Tunable filters
Nationell ämneskategori
Medicinsk laboratorie- och mätteknik
Identifikatorer
URN: urn:nbn:se:liu:diva-15190DOI: 10.1117/12.698165ISI: 000245855200002ISBN: 9780819465542 (tryckt)OAI: oai:DiVA.org:liu-15190DiVA, id: diva2:113602
Konferens
Imaging, Manipulation, and Analysis of Biomolecules, Cells, and Tissues V, 20 January 2007, San Jose, CA, USA
Tillgänglig från: 2008-10-22 Skapad: 2008-10-22 Senast uppdaterad: 2014-01-30Bibliografiskt granskad
Ingår i avhandling
1. In Vivo Diffuse Reflectance Spectroscopy of Human Tissue: From Point Measurements to Imaging
Öppna denna publikation i ny flik eller fönster >>In Vivo Diffuse Reflectance Spectroscopy of Human Tissue: From Point Measurements to Imaging
2008 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

This thesis presents the non-invasive use of diffuse reflectance spectroscopy (DRS) to provide information about the biochemical composition of living tissue. During DRS measurements, the incident, visible light is partially absorbed by chromophores but also scattered in the tissue before being remitted.

Human skin and heart, the main tissue objects in this thesis, are dependent on a sufficient inflow of oxygenized blood, and outflow of metabolic byproducts. This process could be monitored by DRS using the spectral fingerprints of the most important tissue chromophores, oxyhemoglobin and deoxyhemoglobin.

The Beer-Lambert law was used to produce models for the DRS and has thus been a foundation for the analyses throughout this work. Decomposition into the different chromophores was performed using least square fitting and tabulated data for chromophore absorptivity.

These techniques were used to study skin tissue erythema induced by a provocation of an applied heat load on EMLA-treated skin. The absorbance differences, attributed to changes in the hemoglobin concentrations, were examined and found to be related to, foremost, an increase in oxyhemoglobin.

To estimate UV-induced border zones between provoked and nonprovoked tissue a modified Beer-Lambert model, approximating the scattering effects, was used. An increase of chromophore content of more than two standard deviations above mean indicated responsive tissue. The analysis revealed an edge with a rather diffuse border, contradictory to the irradiation pattern.

Measuring in the operating theater, on the heart, it was necessary to calculate absolute chromophore values in order to assess the state of the myocardium. Therefore, a light transport model accounting for the optical properties, and a calibrated probe, was adopted and used. The absolute values and fractions of the chromophores could then be compared between sites and individuals, despite any difference of the optical properties in the tissue.

A hyperspectral imaging system was developed to visualize the spatial distribution of chromophores related to UV-provocations. A modified Beer-Lambert approximation was used including the chromophores and a baseline as an approximate scattering effect. The increase in chromophore content was estimated and evaluated over 336 hours.

In conclusion, advancing from a restricted Beer-Lambert model, into a model estimating the tissue optical properties, chromophore estimation algorithms have been refined progressively. This has allowed advancement from relative chromophore analysis to absolute values, enabling precise comparisons and good prediction of physiological conditions.

Ort, förlag, år, upplaga, sidor
Linköping: Linköping University Electronic Press, 2008. s. 88
Serie
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1210
Nationell ämneskategori
Medicinsk laboratorie- och mätteknik
Identifikatorer
urn:nbn:se:liu:diva-15191 (URN)978-91-7393-809-9 (ISBN)
Disputation
2008-10-31, Elsa Brändströmsalen, Södra entrén, Campus US, Universitetssjukhuset, Linköpings universitet, Linköping, 09:00 (Engelska)
Opponent
Handledare
Tillgänglig från: 2008-10-22 Skapad: 2008-10-22 Senast uppdaterad: 2021-12-28Bibliografiskt granskad

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Ilias, Michail A.Häggblad, ErikAnderson, ChrisSalerud, Göran

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Ilias, Michail A.Häggblad, ErikAnderson, ChrisSalerud, Göran
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Biomedicinsk instrumentteknikTekniska högskolanAvdelningen för dermatologi och venereologiHälsouniversitetetHudkliniken US
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