title: Strip-based registration of serially acquired optical coherence tomography angiography.
abstract: The visibility of retinal microvasculature in optical coherence tomography angiography (OCT-A) images is negatively affected by the small dimension of the capillaries, pulsatile blood flow, and motion artifacts. Serial acquisition and time-averaging of multiple OCT-A images can enhance the definition of the capillaries and result in repeatable and consistent visualization. We demonstrate an automated method for registration and averaging of serially acquired OCT-A images. Ten OCT-A volumes from six normal control subjects were acquired using our prototype 1060-nm swept source OCT system. The volumes were divided into microsaccade-free en face angiogram strips, which were affine registered using scale-invariant feature transform keypoints, followed by nonrigid registration by pixel-wise local neighborhood matching. The resulting averaged images were presented of all the retinal layers combined, as well as in the superficial and deep plexus layers separately. The contrast-to-noise ratio and signal-to-noise ratio of the angiograms with all retinal layers (reported as average ± standard deviation ) increased from 0.52 ± 0.22 and 19.58 ± 4.04 ?? dB for a single image to 0.77 ± 0.25 and 25.05 ± 4.73 ?? dB , respectively, for the serially acquired images after registration and averaging. The improved visualization of the capillaries can enable robust quantification and study of minute changes in retinal microvasculature.
authors.affiliation: Simon Fraser University, School of Engineering Science, Faculty of Applied Sciences, Burnaby, British Columbia, Canada.
authors.forename: Morgan
authors.initials: M
authors.lastname: Heisler
authors.affiliation: Simon Fraser University, School of Engineering Science, Faculty of Applied Sciences, Burnaby, British Columbia, Canada.
authors.forename: Sieun
authors.initials: S
authors.lastname: Lee
authors.affiliation: University of British Columbia, Department of Ophthalmology and Visual Sciences, Vancouver, British Columbia, Canada.
authors.forename: Zaid
authors.initials: Z
authors.lastname: Mammo
authors.affiliation: Simon Fraser University, School of Engineering Science, Faculty of Applied Sciences, Burnaby, British Columbia, Canada.
authors.forename: Yifan
authors.initials: Y
authors.lastname: Jian
authors.affiliation: Simon Fraser University, School of Engineering Science, Faculty of Applied Sciences, Burnaby, British Columbia, Canada.
authors.forename: MyeongJin
authors.initials: M
authors.lastname: Ju
authors.affiliation: University of British Columbia, Department of Ophthalmology and Visual Sciences, Vancouver, British Columbia, Canada.
authors.forename: Andrew
authors.initials: A
authors.lastname: Merkur
authors.affiliation: University of British Columbia, Department of Ophthalmology and Visual Sciences, Vancouver, British Columbia, Canada.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Navajas
authors.affiliation: University of British Columbia, Department of Ophthalmology and Visual Sciences, Vancouver, British Columbia, CanadacUniversity of Western Australia, Lions Eye Institute, Centre for Ophthalmology and Visual Science, Department of Physiology and Pharmacology, Nedlands, AustraliadVitreous Retina Macula Consultants of New York, New York, United StateseManhattan Eye, Ear and Throat Hospital, LuEsther T. Mertz Retinal Research Center, New York, New York, United States.
authors.forename: Chandrakumar
authors.initials: C
authors.lastname: Balaratnasingam
authors.affiliation: Simon Fraser University, School of Engineering Science, Faculty of Applied Sciences, Burnaby, British Columbia, Canada.
authors.forename: Mirza Faisal
authors.initials: MF
authors.lastname: Beg
authors.affiliation: Simon Fraser University, School of Engineering Science, Faculty of Applied Sciences, Burnaby, British Columbia, Canada.
authors.forename: Marinko V
authors.initials: MV
authors.lastname: Sarunic
mesh_terms: D002196:Capillaries / Q000000981:diagnostic imaging*; D005451:Fluorescein Angiography; D006801:Humans; D015203:Reproducibility of Results; D012160:Retina / Q000000981:diagnostic imaging*; D041623:Tomography, Optical Coherence