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The Scientific World Journal
Volume 2014 (2014), Article ID 467462, 7 pages
http://dx.doi.org/10.1155/2014/467462
Research Article

Zone Specific Fractal Dimension of Retinal Images as Predictor of Stroke Incidence

1School of Electrical and Computer Engineering, RMIT University, 124 Latrobe Street, Melbourne, VIC 3000, Australia
2Department of Optometry and Visual Science, Kulliyyah of Allied Health Sciences (KAHS), International Islamic University Malaysia (IIUM), Bandar Indera Mahkota, 25200 Kuantan, Pahang, Malaysia
3Department of Public Health, Yamagata University Faculty of Medicine, 2-2-2 Iida-Nishi, Yamagata-shi, Yamagata 990-9585, Japan
4Centre for Vision Research, Department of Ophthalmology and Westmead Millennium Institute, University of Sydney, 176 Hawkesbury Road, Westmead, NSW 2145, Australia

Received 21 July 2014; Revised 21 October 2014; Accepted 3 November 2014; Published 18 November 2014

Academic Editor: Sandra C. Fuchs

Copyright © 2014 Behzad Aliahmad et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Fractal dimensions (FDs) are frequently used for summarizing the complexity of retinal vascular. However, previous techniques on this topic were not zone specific. A new methodology to measure FD of a specific zone in retinal images has been developed and tested as a marker for stroke prediction. Higuchi’s fractal dimension was measured in circumferential direction (FDC) with respect to optic disk (OD), in three concentric regions between OD boundary and 1.5 OD diameter from its margin. The significance of its association with future episode of stroke event was tested using the Blue Mountain Eye Study (BMES) database and compared against spectrum fractal dimension (SFD) and box-counting (BC) dimension. Kruskal-Wallis analysis revealed FDC as a better predictor of stroke (, , ) compared with SFD (, , ) and BC (, , ) with overall lower median value for the cases compared to the control group. This work has shown that there is a significant association between zone specific FDC of eye fundus images with future episode of stroke while this difference is not significant when other FD methods are employed.