title: Zone specific fractal dimension of retinal images as predictor of stroke incidence.
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 (H = 5.80, P = 0.016, α = 0.05) compared with SFD (H = 0.51, P = 0.475, α = 0.05) and BC (H = 0.41, P = 0.520, α = 0.05) 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.
authors.affiliation: School of Electrical and Computer Engineering, RMIT University, 124 Latrobe Street, Melbourne, VIC 3000, Australia.
authors.forename: Behzad
authors.identifier: 0000-0002-5671-4913
authors.initials: B
authors.lastname: Aliahmad
authors.affiliation: School of Electrical and Computer Engineering, RMIT University, 124 Latrobe Street, Melbourne, VIC 3000, Australia.
authors.forename: Dinesh Kant
authors.initials: DK
authors.lastname: Kumar
authors.affiliation: School of Electrical and Computer Engineering, RMIT University, 124 Latrobe Street, Melbourne, VIC 3000, Australia.
authors.forename: Hao
authors.initials: H
authors.lastname: Hao
authors.affiliation: School of Electrical and Computer Engineering, RMIT University, 124 Latrobe Street, Melbourne, VIC 3000, Australia.
authors.forename: Premith
authors.initials: P
authors.lastname: Unnikrishnan
authors.affiliation: Department of Optometry and Visual Science, Kulliyyah of Allied Health Sciences (KAHS), International Islamic University Malaysia (IIUM), Bandar Indera Mahkota, 25200 Kuantan, Pahang, Malaysia.
authors.forename: Mohd Zulfaezal
authors.identifier: 0000-0001-5496-0822
authors.initials: MZ
authors.lastname: Che Azemin
authors.affiliation: Department of Public Health, Yamagata University Faculty of Medicine, 2-2-2 Iida-Nishi, Yamagata-shi, Yamagata 990-9585, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Kawasaki
authors.affiliation: Centre for Vision Research, Department of Ophthalmology and Westmead Millennium Institute, University of Sydney, 176 Hawkesbury Road, Westmead, NSW 2145, Australia.
authors.forename: Paul
authors.initials: P
authors.lastname: Mitchell
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D005260:Female; D017709:Fractals; D006801:Humans; D007091:Image Processing, Computer-Assisted; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012160:Retina / Q000473:pathology*; D012171:Retinal Vessels / Q000473:pathology; D018709:Statistics, Nonparametric; D020521:Stroke / Q000175:diagnosis* / Q000453:epidemiology*