In vivo imaging of human vasculature in the chorioretinal complex using phase-variance contrast method with phase-stabilized 1-μm swept-source optical coherence tomography

Abstract

We present a noninvasive phase-variance (pv)–based motion contrast method for depth-resolved imaging of the human chorioretinal complex microcirculation with a newly developed phase-stabilized high speed (100-kHz A-scans/s) 1-μm swept- ource optical coherence tomography (SSOCT) system. Compared to our previous spectral-domain (spectrometer based) pv-spectral domain OCT (SDOCT) system, this system has the advantages of higher sensitivity, reduced fringe wash-out for high blood flow speeds and deeper penetration in choroid. High phase stability SSOCT imaging was achieved by using a computationally efficient phase stabilization approach. This process does not require additional calibration hardware and complex numerical procedures. Our phase stabilization method is simple and can be employed in a variety of SSOCT systems. Examples of vasculature in the chorioretinal complex imaged by pv-SSOCT from normal as well as diseased eyes are presented and compared to retinal images of the same subjects acquired with fluorescein angiography and indocyanine green angiography. Observations of morphology of vascular perfusion in chorioretinal complex visualized by our method are listed.

Advances in bone marrow stem cell therapy for retinal dysfunction

“…Such changes were not appreciated using commercially available spectral-domain OCT instruments. With the advent of improved axial range using swept source OCT instruments, subtle changes in the vitreous, vitreo-retinal interface and structures deep to the retina may be appreciated (Unterhuber et al, 2005; Poddar et al, 2014). This may improve our visualization of the stem cells in the vitreous or vitreo-retinal interface following intravitreal injection as they migrate into the retinal layers or the retinal surface.…”

In vivo volumetric depth-resolved vasculature imaging of human limbus and sclera with 1 μm swept source phase-variance optical coherence angiography

“…In recent years the class of OCT methods detecting blood perfusion rather than quantifying flow (also called optical coherence angiography) has been developed and successfully applied to map volumetric vasculature. As an example the phase variance technique provides good results for detecting blood perfusion [19, 20]. Another method, speckle variance, is based on changes in structural image intensity and has been described for tumor microvascular imaging [21].…”

“…Another method, speckle variance, is based on changes in structural image intensity and has been described for tumor microvascular imaging [21]. Most ophthalmic applications of these methods [14, 18, 20] have been applied to visualize retinal vasculature. More recently, quantitative characterization of different vascular networks and visualization of capillaries of the anterior segment have been reported [22, 23].…”

High-speed swept source optical coherence Doppler tomography for deep brain microvascular imaging

“…A recent interesting method used a fiber Bragg grating (FBG) in one of the balanced detection arms to track each spectral sweeping and thus correct the phase jittering between A-scans for ODT reconstruction17. Although much simpler, this method involved accurately matching the pathlengths between the two arms, but improved OCA image quality was shown1819.…”