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Correcting for possible tissue distortion between provocation and assessment in skin testing: The divergent beam UVB photo-test

Authors

  • Jim O'Doherty,

    1. Division of Imaging Sciences & Biomedical Engineering, King's College London, St Thomas’ Hospital, London, United Kingdom
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  • Joakim Henricson,

    1. Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
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  • Magnus Falk,

    1. Division of Community Medicine, Primary care, Department of Medical and Health Sciences, Linköping, Sweden
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  • Chris D. Anderson

    Corresponding author
    1. Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
    • Division of Imaging Sciences & Biomedical Engineering, King's College London, St Thomas’ Hospital, London, United Kingdom
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Address:

Prof Chris Anderson

Department of Clinical and Experimental Medicine

Linkoping University Hospital

Linkoping

S581-85

Sweden

Tel: +46 10 103 1750

Fax: +46 10 103 3686

e-mail: chris.anderson@lio.se

Abstract

Background

In tissue viability imaging (TiVi), an assessment method for skin erythema, correct orientation of skin position from provocation to assessment optimizes data interpretation. Image processing algorithms could compensate for the effects of skin translation, torsion and rotation realigning assessment images to the position of the skin at provocation.

Methods

A reference image of a divergent, UVB phototest was acquired, as well as test images at varying levels of translation, rotation and torsion. Using 12 skin markers, an algorithm was applied to restore the distorted test images to the reference image.

Results

The algorithm corrected torsion and rotation up to approximately 35 degrees. The radius of the erythemal reaction and average value of the input image closely matched that of the reference image's ‘true value’.

Conclusion

The image ‘de-warping’ procedure improves the robustness of the response image evaluation in a clinical research setting and opens the possibility of the correction of possibly flawed images performed away from the laboratory setting by the subject/patient themselves. This opportunity may increase the use of photo-testing and, by extension, other late response skin testing where the necessity of a return assessment visit is a disincentive to performance of the test.

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