Applicability of quantitative optical imaging techniques for intraoperative perfusion diagnostics: a comparison of laser speckle contrast imaging, sidestream dark-field microscopy, and optical coherence tomography

Myopia is the most common refractive error and the subject of interest of various studies assessing ocular blood flow. Increasing refractive error and axial elongation of the eye result in the stretching and thinning of the scleral, choroid, and retinal tissues and the decrease in retinal vessel diameter, disturbing ocular blood flow. Local and systemic factors known to change ocular blood flow include glaucoma, medications and fluctuations in intraocular pressure, and metabolic parameters. Techniques and tools assessing ocular blood flow include, among others, laser Doppler flowmetry (LDF), retinal function imager (RFI), laser speckle contrast imaging (LSCI), magnetic resonance imaging (MRI), optical coherence tomography angiography (OCTA), pulsatile ocular blood flowmeter (POBF), fundus pulsation amplitude (FPA), colour Doppler imaging (CDI), and Doppler optical coherence tomography (DOCT). Many researchers consistently reported lower blood flow parameters in myopic eyes regardless of the used diagnostic method. It is unclear whether this is a primary change that causes secondary thinning of ocular tissues or quite the opposite; that is, the mechanical stretching of the eye wall reduces its thickness and causes a secondary lower demand of tissues for oxygen. This paper presents a review of studies assessing ocular blood flow in myopes.

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Optical coherence Doppler tomography quantifies laser speckle contrast imaging for blood flow imaging in the rat cerebral cortex

Optics Letters ◽

10.1364/ol.33.001156 ◽

2008 ◽

Vol 33 (10) ◽

pp. 1156 ◽

Cited By ~ 18

Author(s):

Zhongchi Luo ◽

Zhenguo Wang ◽

Zhijia Yuan ◽

Congwu Du ◽

Yingtian Pan

Keyword(s):

Blood Flow ◽

Cerebral Cortex ◽

Laser Speckle ◽

Flow Imaging ◽

Optical Coherence ◽

Contrast Imaging ◽

Doppler Tomography ◽

Laser Speckle Contrast Imaging ◽

Blood Flow Imaging ◽

Speckle Contrast

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Biophotonics Modalities for High-Resolution Imaging of Microcirculatory Tissue Beds Using Endogenous Contrast: A Review on Present Scenario and Prospects

International Journal of Optics ◽

10.1155/2011/293684 ◽

2011 ◽

Vol 2011 ◽

pp. 1-20 ◽

Cited By ~ 4

Author(s):

Hrebesh M. Subhash

Keyword(s):

High Resolution ◽

Optical Imaging ◽

Perfusion Imaging ◽

Imaging Techniques ◽

Laser Speckle ◽

Contrast Imaging ◽

Endogenous Contrast ◽

Contrast Mechanism ◽

Recent Developments ◽

Resolution Imaging

The microcirculation is a complex system, and the visualization of microcirculation has great significance in improving our understanding of pathophysiological processes in various disease conditions, in both clinical and fundamental studies. A range of techniques are available or emerging for investigating different aspect of the microcirculation in animals and humans. This paper reviews the recent developments in the field of high-resolution and high-sensitive optical imaging of microcirculatory tissue beds, emphasizing technologies that utilize the endogenous contrast mechanism. Optical imaging techniques such as intravital microscopy, Capillaroscopy, laser Doppler perfusion imaging, laser speckle perfusion imaging, polarization spectroscopy, photo-acoustic tomography, and various implementations of optical coherence tomography based on Doppler and speckle contrast imaging are presented together with their prospectives and challenges.

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Combining Laser Doppler Speckle Contrast Imaging and Optical Coherence Tomography for Quantitative Imaging of Cortical Blood Flow in Rat Brain

10.1364/biomed.2008.bwc2 ◽

2008 ◽

Author(s):

Zhongchi Luo ◽

Zhenguo Wang ◽

Zhijia Yuan ◽

Congwu Du ◽

Yingtian Pan

Keyword(s):

Blood Flow ◽

Optical Coherence Tomography ◽

Rat Brain ◽

Quantitative Imaging ◽

Laser Doppler ◽

Optical Coherence ◽

Contrast Imaging ◽

Cortical Blood Flow ◽

Speckle Contrast

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Assessment of flow within developing chicken vasculature and biofabricated vascularized tissues using multimodal imaging techniques

Scientific Reports ◽

10.1038/s41598-021-97008-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Prasanna Padmanaban ◽

Ata Chizari ◽

Tom Knop ◽

Jiena Zhang ◽

Vasileios D. Trikalitis ◽

...

Keyword(s):

Fluid Flow ◽

Imaging Techniques ◽

Dark Field ◽

Flow Dynamics ◽

Laser Speckle ◽

Shear Stresses ◽

Imaging Data ◽

Contrast Imaging ◽

Flow Shear ◽

Engineered Tissues

AbstractFluid flow shear stresses are strong regulators for directing the organization of vascular networks. Knowledge of structural and flow dynamics information within complex vasculature is essential for tuning the vascular organization within engineered tissues, by manipulating flows. However, reported investigations of vascular organization and their associated flow dynamics within complex vasculature over time are limited, due to limitations in the available physiological pre-clinical models, and the optical inaccessibility and aseptic nature of these models. Here, we developed laser speckle contrast imaging (LSCI) and side-stream dark field microscopy (SDF) systems to map the vascular organization, spatio-temporal blood flow fluctuations as well as erythrocytes movements within individual blood vessels of developing chick embryo, cultured within an artificial eggshell system. By combining imaging data and computational simulations, we estimated fluid flow shear stresses within multiscale vasculature of varying complexity. Furthermore, we demonstrated the LSCI compatibility with bioengineered perfusable muscle tissue constructs, fabricated via molding techniques. The presented application of LSCI and SDF on perfusable tissues enables us to study the flow perfusion effects in a non-invasive fashion. The gained knowledge can help to use fluid perfusion in order to tune and control multiscale vascular organization within engineered tissues.

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Quantitative laser speckle flowmetry of the in vivo microcirculation using sidestream dark field microscopy

Biomedical Optics Express ◽

10.1364/boe.4.002347 ◽

2013 ◽

Vol 4 (11) ◽

pp. 2347 ◽

Cited By ~ 21

Author(s):

Annemarie Nadort ◽

Rutger G. Woolthuis ◽

Ton G. van Leeuwen ◽

Dirk J. Faber

Keyword(s):

Dark Field ◽

Laser Speckle ◽

Sidestream Dark Field ◽

Dark Field Microscopy

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Optimization of X-ray Investigations in Dentistry Using Optical Coherence Tomography

Sensors ◽

10.3390/s21134554 ◽

2021 ◽

Vol 21 (13) ◽

pp. 4554

Author(s):

Ralph-Alexandru Erdelyi ◽

Virgil-Florin Duma ◽

Cosmin Sinescu ◽

George Mihai Dobre ◽

Adrian Bradu ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Radiation Dose ◽

Imaging Techniques ◽

Image Resolution ◽

Optical Coherence ◽

X Rays ◽

High Quality ◽

X Ray

The most common imaging technique for dental diagnoses and treatment monitoring is X-ray imaging, which evolved from the first intraoral radiographs to high-quality three-dimensional (3D) Cone Beam Computed Tomography (CBCT). Other imaging techniques have shown potential, such as Optical Coherence Tomography (OCT). We have recently reported on the boundaries of these two types of techniques, regarding. the dental fields where each one is more appropriate or where they should be both used. The aim of the present study is to explore the unique capabilities of the OCT technique to optimize X-ray units imaging (i.e., in terms of image resolution, radiation dose, or contrast). Two types of commercially available and widely used X-ray units are considered. To adjust their parameters, a protocol is developed to employ OCT images of dental conditions that are documented on high (i.e., less than 10 μm) resolution OCT images (both B-scans/cross sections and 3D reconstructions) but are hardly identified on the 200 to 75 μm resolution panoramic or CBCT radiographs. The optimized calibration of the X-ray unit includes choosing appropriate values for the anode voltage and current intensity of the X-ray tube, as well as the patient’s positioning, in order to reach the highest possible X-rays resolution at a radiation dose that is safe for the patient. The optimization protocol is developed in vitro on OCT images of extracted teeth and is further applied in vivo for each type of dental investigation. Optimized radiographic results are compared with un-optimized previously performed radiographs. Also, we show that OCT can permit a rigorous comparison between two (types of) X-ray units. In conclusion, high-quality dental images are possible using low radiation doses if an optimized protocol, developed using OCT, is applied for each type of dental investigation. Also, there are situations when the X-ray technology has drawbacks for dental diagnosis or treatment assessment. In such situations, OCT proves capable to provide qualitative images.

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Nephron blood flow dynamics measured by laser speckle contrast imaging

AJP Renal Physiology ◽

10.1152/ajprenal.00417.2010 ◽

2011 ◽

Vol 300 (2) ◽

pp. F319-F329 ◽

Cited By ~ 34

Author(s):

Niels-Henrik Holstein-Rathlou ◽

Olga V. Sosnovtseva ◽

Alexey N. Pavlov ◽

William A. Cupples ◽

Charlotte Mehlin Sorensen ◽

...

Keyword(s):

Blood Flow ◽

Signal Transmission ◽

Experimental Studies ◽

Flow Dynamics ◽

Laser Speckle ◽

Tubuloglomerular Feedback ◽

Contrast Imaging ◽

Laser Speckle Contrast Imaging ◽

Speckle Contrast ◽

Blood Flow Dynamics

Tubuloglomerular feedback (TGF) has an important role in autoregulation of renal blood flow and glomerular filtration rate (GFR). Because of the characteristics of signal transmission in the feedback loop, the TGF undergoes self-sustained oscillations in single-nephron blood flow, GFR, and tubular pressure and flow. Nephrons interact by exchanging electrical signals conducted electrotonically through cells of the vascular wall, leading to synchronization of the TGF-mediated oscillations. Experimental studies of these interactions have been limited to observations on two or at most three nephrons simultaneously. The interacting nephron fields are likely to be more extensive. We have turned to laser speckle contrast imaging to measure the blood flow dynamics of 50–100 nephrons simultaneously on the renal surface of anesthetized rats. We report the application of this method and describe analytic techniques for extracting the desired data and for examining them for evidence of nephron synchronization. Synchronized TGF oscillations were detected in pairs or triplets of nephrons. The amplitude and the frequency of the oscillations changed with time, as did the patterns of synchronization. Synchronization may take place among nephrons not immediately adjacent on the surface of the kidney.

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