A digital frequency ramping method for enhancing doppler flow imaging in Fourier-domain optical coherence tomography

Abstract

A digital frequency ramping method (DFRM) is proposed to improve the signal-to-noise ratio (SNR) of Doppler flow imaging in Fourier-domain optical coherence tomography (FDOCT). To examine the efficacy of DFRM for enhancing flow detection, computer simulation and tissue phantom study were conducted for phase noise reduction and flow quantification. In addition, the utility of this technique was validated in our in vivo clinical bladder imaging with endoscopic FDOCT. The Doppler flow images reconstructed by DFRM were compared with the counterparts by traditional Doppler FDOCT. The results demonstrate that DFRM enables real-time Doppler FDOCT imaging at significantly enhanced sensitivity without hardware modification, thus rendering it uniquely suitable for endoscopic subsurface blood flow imaging and diagnosis.

Noninvasive and High-Resolution Optical Monitoring of Healing of Diabetic Dermal Excisional Wounds Implanted with Biodegradable In Situ Gelable Hydrogels

“…Recent technological advances in OCT, for example, polarization-sensitive OCT, 11 have enabled more specific complementary diagnosis potentially very useful for enhancing the assessment of wound repair. For instance, recent technological advances in Doppler OCT have dramatically enhanced the sensitivity and resolution to image minute subsurface blood flows in 2D and even 3D, [22][23][24] thus rendering it a promising technique to detect neo-vascularization, which is a crucial physiological parameter for wound repair. Polarization-sensitive OCT can provide better identification of collagen or other fibrous tissue components.…”

Imaging separation of neuronal from vascular effects of cocaine on rat cortical brain in vivo

“…Recent advances in OCT angiography(Wang et al, 2007) dramatically improved the sensitivity for flow detection by applying Hilbert transform to the detected I OCT (k; Δ L, x) along the transverse x-axis, i.e., frequency offsetting to reduce background phase noise. We further developed DFR-OCT(Yuan et al, 2009), a simple digital-frequency-ramping method to enhance flow detection which can be applied to conventional SDOCT with no hardware modification. Importantly, DFR-OCT enables quantitative 2D and 3D Doppler flow imaging by digitally ramping threshold frequency v R in Hilbert transforms, i.e., φ τ (Δ L, x) in Eq.…”

Advances in Doppler OCT

“…Yuan et al . proposed a digital frequency ramping method by numerically introducing a phase shift into the original spectral interferometric signal using a Hilbert transform [63] . Tao et al .…”