title: Phase-variance optical coherence tomography: a technique for noninvasive angiography.
abstract: OBJECTIVE
  Phase-variance optical coherence tomography (PV-OCT) provides volumetric imaging of the retinal vasculature without the need for intravenous injection of a fluorophore. We compare images from PV-OCT and fluorescein angiography (FA) for normal individuals and patients with age-related macular degeneration (AMD) and diabetic retinopathy.
  
  
  METHODS
  This is an evaluation of a diagnostic technology.
  
  
  METHODS
  Four patients underwent comparative retinovascular imaging using FA and PV-OCT. Imaging was performed on 1 normal individual, 1 patient with dry AMD, 1 patient with exudative AMD, and 1 patient with nonproliferative diabetic retinopathy.
  
  
  METHODS
  Fluorescein angiography imaging was performed using a Topcon Corp (Tokyo, Japan) (TRC-50IX) camera with a resolution of 1280 (H) × 1024 (V) pixels. The PV-OCT images were generated by software data processing of the entire cross-sectional image from consecutively acquired B-scans. Bulk axial motion was calculated and corrected for each transverse location, reducing the phase noise introduced from eye motion. Phase variance was calculated through the variance of the motion-corrected phase changes acquired within multiple B-scans at the same position. Repeating these calculations over the entire volumetric scan produced a 3-dimensional PV-OCT representation of the vasculature.
  
  
  METHODS
  Feasibility of rendering retinal and choroidal microvasculature using PV-OCT was compared qualitatively with FA, the current gold standard for retinovascular imaging.
  
  
  RESULTS
  Phase-variance OCT noninvasively rendered a 2-dimensional depth color-coded vasculature map of the retinal and choroidal vasculature. The choriocapillaris was imaged with better resolution of microvascular detail using PV-OCT. Areas of geographic atrophy and choroidal neovascularization imaged by FA were depicted by PV-OCT. Regions of capillary nonperfusion from diabetic retinopathy were shown by both imaging techniques; there was not complete correspondence between microaneurysms shown on FA and PV-OCT images.
  
  
  CONCLUSIONS
  Phase-variance OCT yields high-resolution imaging of the retinal and choroidal microvasculature that compares favorably with FA.
authors.affiliation: Department of Ophthalmology & Vision Science, University of California San Francisco, San Francisco, California. Electronic address: danschwartz7@gmail.com.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Schwartz
authors.affiliation: Department of Biology, California Institute of Technology, Pasadena, California.
authors.forename: Jeff
authors.initials: J
authors.lastname: Fingler
authors.affiliation: Department of Biology, California Institute of Technology, Pasadena, California; Department of Ophthalmology & Vision Science, University of California Davis, Davis, California.
authors.forename: Dae Yu
authors.initials: DY
authors.lastname: Kim
authors.affiliation: Department of Ophthalmology & Vision Science, University of California Davis, Davis, California.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Zawadzki
authors.affiliation: Department of Ophthalmology & Vision Science, University of California Davis, Davis, California.
authors.forename: Lawrence S
authors.initials: LS
authors.lastname: Morse
authors.affiliation: Department of Ophthalmology & Vision Science, University of California Davis, Davis, California.
authors.forename: Susanna S
authors.initials: SS
authors.lastname: Park
authors.affiliation: Department of Biology, California Institute of Technology, Pasadena, California.
authors.forename: Scott E
authors.initials: SE
authors.lastname: Fraser
authors.affiliation: Department of Ophthalmology & Vision Science, University of California Davis, Davis, California.
authors.forename: John S
authors.initials: JS
authors.lastname: Werner
mesh_terms: D000328:Adult; D000369:Aged, 80 and over; D002829:Choroid / Q000098:blood supply*; D020256:Choroidal Neovascularization / Q000175:diagnosis; D003930:Diabetic Retinopathy / Q000175:diagnosis*; D005260:Female; D005451:Fluorescein Angiography; D057092:Geographic Atrophy / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012171:Retinal Vessels / Q000473:pathology*; D041623:Tomography, Optical Coherence / Q000379:methods*; D057135:Wet Macular Degeneration / Q000175:diagnosis*