Universität zu Köln

Sarandi, I., Classen, D. P., Astvatsatourov, A., Pfaar, O., Klimek, L., Moesges, R. and Deserno, T. M. (2014). Quantitative Conjunctival Provocation Test for Controlled Clinical Trials. Methods Inf. Med., 53 (4). S. 238 - 245. STUTTGART: GEORG THIEME VERLAG KG. ISSN 2511-705X

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Abstract

Background: The conjunctival provocation test (CPT) is a diagnostic procedure for the assessment of allergic diseases. Photographs are taken before and after provocation increasing the redness of the conjunctiva due to hyperemia. Objective: We propose and evaluate an automatic image processing pipeline for objective and quantitative CPT. Method: After scale normalization based on intrinsic image features, the conjunctiva region of interest (ROI) is segmented combining thresholding, edge detection and Hough transform. Redness of the ROI is measured from 0 to 1 by the average pixel redness, which is defined by truncated projection in HSV space. In total, 92 images from an observational diagnostic study are processed for evaluation. The database contains images from two visits for assessment of the test-retest reliability (46 images per visit). Result: All images were successfully processed by the algorithm. The relative redness increment correlates between the two visits with Pearson's r = 0.672 (p < .001), Linear correlation of the automatic measure is larger than the manual measure (r = 0.59). This indicates a higher reproducibility and stability of the automatic method. Conclusion: We presented a robust and effective way to objectify CPT. The algorithm operates on low resolution, is fast and : requires no manual input. Quantitative CPT measures can now be established as surrogate endpoint in controlled clinical trials.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Sarandi, I. UNSPECIFIED UNSPECIFIED UNSPECIFIED Classen, D. P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Astvatsatourov, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Pfaar, O. UNSPECIFIED UNSPECIFIED UNSPECIFIED Klimek, L. UNSPECIFIED UNSPECIFIED UNSPECIFIED Moesges, R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Deserno, T. M. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-449793
DOI:	10.3414/ME13-12-0142
Journal or Publication Title:	Methods Inf. Med.
Volume:	53
Number:	4
Page Range:	S. 238 - 245
Date:	2014
Publisher:	GEORG THIEME VERLAG KG
Place of Publication:	STUTTGART
ISSN:	2511-705X
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language Computer Science, Information Systems; Health Care Sciences & Services; Medical Informatics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/44979