Real-time bulk-motion-correction free Doppler variance optical coherence tomography for choroidal capillary vasculature imaging

Abstract

In this paper, we analyze the retinal and choroidal blood vasculature in the posterior segment of the human eye with optimized color Doppler and Doppler variance optical coherence tomography. Depth-resolved structure, color Doppler and Doppler variance images are compared. Blood vessels down to the capillary level were detected and visualized with the optimized optical coherence color Doppler and Doppler variance method. For in-vivo imaging of human eyes, bulk-motion induced bulk phase must be identified and removed before using the color Doppler method. It was found that the Doppler variance method is not sensitive to bulk-motion and the method can be used without correcting the bulk-motion when the sample-movement-induced velocity changes gradually. Real-time processing and displaying of the structure and blood vessel images are very interesting and is demonstrated using a dual quad-core Central Processing Unit (CPU) workstation. High resolution images of choroidal capillary of the vasculature network with phased-resolved color Doppler and Doppler variance are shown.

Phase-Resolved Doppler Optical Coherence Tomography

“…Figure 11 shows images of the hamster skin installed in a dorsal window chamber. The images are obtained with a charge-coupled device (CCD) spectrometer-based OCT system [42]. Figures 11(a) [24,37].…”

“…Because of its high spatial resolution and velocity sensitivity, Doppler OCT has been widely used for blood flow related biomedical applications [41][42][43][44][45][46][47][48]. These applications require imaging of blood flow in-vivo.…”

“…The correction may also introduce artifacts when the blood vessels are large and take most of the pixels for an A-line [35,45]. We have shown that the Doppler variance method is not sensitive to bulk-motion and the method can be used without correcting the bulk-motion when the sample-movement-induced velocity changes gradually [42]. However, for the Doppler variance, we can rewrite Eq.…”

“…Blood flow related biomedical applications with PRODT have been demonstrated for imaging ocular blood flow, mapping cortical hemodynamics for brain research, drug screening, monitoring changes in image tissue morphology and hemodynamics following pharmacological intervention and photodynamic therapy, evaluating the efficacy of laser treatment in port wine stain (PWS) patients, assessing the depth of burn wounds, imaging tumor microenvironment, and quantifying cerebral blood flow [41][42][43][44][45][46][47][48]. There have been excellent review papers or book chapters about the advances of PRODT [2 and 50].…”

An improved algorithm of structural image reconstruction with rapid scanning optical delay line for Optical Coherence Tomography

“…But due to imperfections of the setup components and mistakes in the process of studying objects like bulk motions of the patient acquired images could have low contrast so it could be very hard to distinguish necessary details of the object, which could be very important in the biomedical diagnostics [3]. Therefore, increasing the image contrast is an important procedure that should be applied in the data processing algorithm.…”