Phase-stabilized optical frequency domain imaging at 1-µm for the measurement of blood flow in the human choroid

Opt Express. 2011 Oct 10;19(21):20886-903. doi: 10.1364/OE.19.020886.

Abstract

In optical frequency domain imaging (OFDI) the measurement of interference fringes is not exactly reproducible due to small instabilities in the swept-source laser, the interferometer and the data-acquisition hardware. The resulting variation in wavenumber sampling makes phase-resolved detection and the removal of fixed-pattern noise challenging in OFDI. In this paper this problem is solved by a new post-processing method in which interference fringes are resampled to the exact same wavenumber space using a simultaneously recorded calibration signal. This method is implemented in a high-speed (100 kHz) high-resolution (6.5 µm) OFDI system at 1-µm and is used for the removal of fixed-pattern noise artifacts and for phase-resolved blood flow measurements in the human choroid. The system performed close to the shot-noise limit (<1dB) with a sensitivity of 99.1 dB for a 1.7 mW sample arm power. Suppression of fixed-pattern noise artifacts is shown up to 39.0 dB which effectively removes all artifacts from the OFDI-images. The clinical potential of the system is shown by the detection of choroidal blood flow in a healthy volunteer and the detection of tissue reperfusion in a patient after a retinal pigment epithelium and choroid transplantation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms
  • Artifacts
  • Calibration
  • Choroid / blood supply*
  • Diagnostic Imaging / methods
  • Equipment Design
  • Fourier Analysis
  • Humans
  • Interferometry / methods
  • Lasers
  • Light
  • Motion
  • Ophthalmology / methods
  • Optics and Photonics / methods*
  • Signal Processing, Computer-Assisted
  • Time Factors
  • Tomography, Optical Coherence / methods