Real-time assessment of retinal blood flow with ultrafast acquisition by color Doppler Fourier domain optical coherence tomography

Leitgeb, Rainer A.; Schmetterer, Leopold; Drexler, Wolfgang; Fercher, Adolf Friedrich; Zawadzki, Robert J.; Bajraszewski, Tomasz

doi:10.1364/oe.11.003116

Cited by 389 publications

(246 citation statements)

References 12 publications

Supporting

Mentioning

241

Contrasting

Unclassified

Order By: Relevance

“…Since the interferometer only measures the relative phase between two optical paths, the phase of the input analytic signal U in is chosen as a reference and the input analytic signal is written as U in (ω,t) = s(ω)exp (-iωt). Then, the output analytic signal U out is the sum of analytic signals at the reference U r (ω,t) and sample arms U s (ω,t) and a frequency response function H(ω,t) of a sample can be written as: (2) where a(y 0 ) is the initial distribution of backscattering amplitude, n s is refractive index of the sample arm, c is the speed of light in free space, and l s is the physical length between the beam splitter and the origin of the y-coordinate. The frequency response function provides the input analytic signal with time delay and compression factors.…”

Section: Theorymentioning

confidence: 99%

Optical sectioning for microfluidics: secondary flow and mixing in a meandering microchannel

2008

View full text Add to dashboard Cite

Secondary flow plays a critical function in a microchannel, such as a micromixer, because it can enhance heat and mass transfer. However, there is no experimental method to visualize the secondary flow and the associated mixing pattern in a microchannel because of difficulties in high-resolution, non-invasive, cross-sectional imaging. Here, we simultaneously imaged and quantified the secondary flow and pattern of two-liquid mixing inside a meandering square microchannel with spectral-domain Doppler optical coherence tomography. We observed an increase in the efficiency of two-liquid mixing when air was injected to produce a bubble-train flow and identified the three-dimensional enhancement mechanism behind the complex mixing phenomena. An alternating pair of counterrotating and toroidal vortices cooperated to enhance two-liquid mixing.

show abstract

Section: Theorymentioning

confidence: 99%

Optical sectioning for microfluidics: secondary flow and mixing in a meandering microchannel

2008

View full text Add to dashboard Cite

show abstract

“…This increased speed will also enhance the capacity of OCT to perform Doppler flow measurements, a technique we and others have previously used in the eye [28,29]. This principle could be adapted to reveal the pancreatic blood flow and provide additional functional variables.…”

Section: Discussionmentioning

confidence: 95%

In vivo imaging of murine endocrine islets of Langerhans with extended-focus optical coherence microscopy

et al. 2009

Self Cite

View full text Add to dashboard Cite

Aims/hypothesis Structural and functional imaging of the islets of Langerhans and the insulin-secreting beta cells represents a significant challenge and a long-lasting objective in diabetes research. In vivo microscopy offers a valuable insight into beta cell function but has severe limitations regarding sample labelling, imaging speed and depth, and was primarily performed on isolated islets lacking native innervations and vascularisation. This article introduces extended-focus optical coherence microscopy (xfOCM) to image murine pancreatic islets in their natural environment in situ, i.e. in vivo and in a label-free condition.Methods Ex vivo measurements on excised pancreases were performed and validated by standard immunohistochemistry to investigate the structures that can be observed with xfOCM. The influence of streptozotocin on the signature of the islets was investigated in a second step. Finally, xfOCM was applied to make measurements of the murine pancreas in situ and in vivo. Results xfOCM circumvents the fundamental physical limit that trades lateral resolution for depth of field, and achieves fast volumetric imaging with high resolution in all three dimensions. It allows label-free visualisation of pancreatic lobules, ducts, blood vessels and individual islets of Langerhans ex vivo and in vivo, and detects streptozotocin-induced islet destruction. Conclusions/interpretation Our results demonstrate the potential value of xfOCM in high-resolution in vivo studies to assess islet structure and function in animal models of diabetes, aiming towards its use in longitudinal studies of diabetes progression and islet transplants.

show abstract

“…An important enhancement is Doppler OCT (DOCT) for blood flow measurements [10,11]. Most of the proposed Doppler approaches are based on the phase shift between subsequently detected OCT signals, which is widely referred to as phase-resolved Doppler OCT (PR-DOCT) [12][13][14]. For the commonly used spectrometer-based OCT systems, PR-DOCT is still limited by a minimum and ambiguous maximum flow velocity, by interference fringe blurring, due to fast axially moving samples and by a nonlinear relation between the Doppler phase shift and the axial sample velocity for the case of an obliquely moving sample.…”

Section: Introductionmentioning

confidence: 99%

Flow Measurement by Lateral Resonant Doppler Optical Coherence Tomography in the Spectral Domain

Walther

Koch

2017

Applied Sciences

View full text Add to dashboard Cite

Abstract:In spectral domain optical coherence tomography (SD-OCT), any transverse motion component of a detected obliquely moving sample results in a nonlinear relationship between the Doppler phase shift and the axial sample velocity restricting phase-resolved Doppler OCT (PR-DOCT). The size of the deviation from the linear relation depends on the amount of the transverse velocity component, given by the Doppler angle, and the height of the absolute sample velocity. Especially for very small Doppler angles between the horizontal and flow direction, and high flow velocities, the detected Doppler phase shift approaches a limiting value, making an unambiguous measurement of the axial sample velocity by PR-DOCT impossible. To circumvent this limitation, we propose a new method for resonant Doppler flow quantification in spectral domain OCT, where the scanner movement velocity is matched with the transverse velocity component of the sample motion similar to a tracking shot, where the camera is moved with respect to the sample. Consequently, the influence of the transverse velocity component of the tracked moving particles on the Doppler phase shift is negligible and the linear relation between the phase shift and the axial velocity component can be considered for flow velocity calculations. The proposed method is verified using flow phantoms on the basis of 1% Intralipid solution and diluted human blood.

show abstract

Real-time assessment of retinal blood flow with ultrafast acquisition by color Doppler Fourier domain optical coherence tomography

Cited by 389 publications

References 12 publications

Optical sectioning for microfluidics: secondary flow and mixing in a meandering microchannel

Optical sectioning for microfluidics: secondary flow and mixing in a meandering microchannel

In vivo imaging of murine endocrine islets of Langerhans with extended-focus optical coherence microscopy

Flow Measurement by Lateral Resonant Doppler Optical Coherence Tomography in the Spectral Domain

Contact Info

Product

Resources

About