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

• Published in: Optics express Vol. 19; no. 21; pp. 20886 - 20903
• Main Authors: Braaf, Boy, Vermeer, Koenraad A, Sicam, Victor Arni D P, van Zeeburg, Elsbeth, van Meurs, Jan C, de Boer, Johannes F
• Format: Journal Article
• Language: English
• Published: United States 10-10-2011
• Subjects: Algorithms; 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
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/oe.19.020886

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.