Resonant Doppler flow imaging and optical vivisection of retinal blood vessels

Bachmann, A. H.; Villiger, Martin; Blatter, Cédric; Lasser, Theo; Leitgeb, Rainer A.

doi:10.1364/oe.15.000408

Cited by 91 publications

(50 citation statements)

References 28 publications

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“…117 Resonant Doppler OCT turns this apparent downside into an advantage when contrasting moving structures, by dynamically tuning the reference arm delay, matching speeds in both arms. 118 Other approaches use spatial frequency filtering techniques, by making use of the fact that moving structures appear shifted in spatial freqeuncy. 119,120 Alternatively, one can operate on the Doppler histogram, 121 or use support vector machines operating on phase difference data.…”

Section: Label-free Optical Angiographymentioning

confidence: 99%

Optical coherence tomography today: speed, contrast, and multimodality

Drexler¹,

Li²,

Kumar³

et al. 2014

J. Biomed. Opt

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419

264

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Abstract. In the last 25 years, optical coherence tomography (OCT) has advanced to be one of the most innovative and most successful translational optical imaging techniques, achieving substantial economic impact as well as clinical acceptance. This is largely owing to the resolution improvements by a factor of 10 to the submicron regime and to the imaging speed increase by more than half a million times to more than 5 million A-scans per second, with the latter one accomplished by the state-of-the-art swept source laser technologies that are reviewed in this article. In addition, parallelization of OCT detection, such as line-field and full-field OCT, has shortened the acquisition time even further by establishing quasi-akinetic scanning. Besides the technical improvements, several functional and contrast-enhancing OCT applications have been investigated, among which the label-free angiography shows great potential for future studies. Finally, various multimodal imaging modalities with OCT incorporated are reviewed, in that these multimodal implementations can synergistically compensate for the fundamental limitations of OCT when it is used alone. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Section: Label-free Optical Angiographymentioning

confidence: 99%

Optical coherence tomography today: speed, contrast, and multimodality

Drexler¹,

Li²,

Kumar³

et al. 2014

J. Biomed. Opt

Self Cite

419

264

View full text Add to dashboard Cite

show abstract

“…Besides structural imaging, OCT has been used extensively for functional imaging, where blood flow imaging in living tissue is arguably one of the most important applications. Blood flow imaging methods based on OCT can be divided into two categories: angiographic methods that image the structure of the vasculature in tissue [2][3][4][5][6][7][8], and velocimetric methods measuring the velocity of red blood cells [9][10][11][12][13][14][15][16][17][18]. While the former techniques use some form of motion contrast to yield a qualitative image of blood vessels, the latter allow a quantitative estimation of the blood flow speed.…”

Section: Introductionmentioning

confidence: 99%

Quantitative lateral and axial flow imaging with optical coherence microscopy and tomography

Bouwens¹,

Szlag²,

Szkulmowski³

et al. 2013

Opt. Express

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Optical coherence tomography (OCT) and optical coherence microscopy (OCM) allow the acquisition of quantitative three-dimensional axial flow by estimating the Doppler shift caused by moving scatterers. Measuring the velocity of red blood cells is currently the principal application of these methods. In many biological tissues, blood flow is often perpendicular to the optical axis, creating the need for a quantitative measurement of lateral flow. Previous work has shown that lateral flow can be measured from the Doppler bandwidth, albeit only for simplified optical systems. In this work, we present a generalized model to analyze the influence of relevant OCT/OCM system parameters such as light source spectrum, numerical aperture and beam geometry on the Doppler spectrum. Our analysis results in a general framework relating the mean and variance of the Doppler frequency to the axial and lateral flow velocity components. Based on this model, we present an optimized acquisition protocol and algorithm to reconstruct quantitative measurements of lateral and axial flow from the Doppler spectrum for any given OCT/OCM system. To validate this approach, Doppler spectrum analysis is employed to quantitatively measure flow in a capillary with both extended focus OCM and OCT.

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“…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: 96%

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

et al. 2009

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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.

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Resonant Doppler flow imaging and optical vivisection of retinal blood vessels

Cited by 91 publications

References 28 publications

Optical coherence tomography today: speed, contrast, and multimodality

Optical coherence tomography today: speed, contrast, and multimodality

Quantitative lateral and axial flow imaging with optical coherence microscopy and tomography

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

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