Laser speckle contrast imaging of blood flow in the deep brain using microendoscopy

Chen, Ming; Wen, Dong; Huang, Shifeng; Gui, Shen; Zhang, Zhihong; Lu, Jinling; Li, Pengcheng

doi:10.1364/ol.43.005627

Cited by 27 publications

(16 citation statements)

References 28 publications

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Section: Methodsmentioning

confidence: 99%

“…The relationship between the flow V and speckle contrast K s (V~(K s ) −2 ) is met when: (1) assuming Lorentzian velocity distribution, (2) camera exposure time /shutter speed (T) > > correlation time of the intensity fluctuations (τ c ), typically T > 100-400 × τ c , and (3) speckle size (which controlled by the camera lens) ≥ 2 × camera pixel size [18,22,23,27,45]. For the reader's information, V is often coined speckle flow index (SFI) and previous works show a linear response range between SFI and flow speed [28,[46][47][48]. The combination of blood flow and chromophore information permits the calculation of tissue oxygen consumption rate (MRO 2 ) which can be approximated by the product between Hbr and flow (Fick's principle) [49].…”

Section: Lsi Image Analysismentioning

confidence: 99%

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Multiparameter wide‐field integrated optical imaging system‐based spatially modulated illumination and laser speckles in model of tissue injuries

Bloygrund

Franjy-Tal

Rosenzweig

et al. 2019

Journal of Biophotonics

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In this report, an integrated optical platform based on spatial illumination together with laser speckle contrast technique was utilized to measure multiple parameters in live tissue including absorption, scattering, saturation, composition, metabolism, and blood flow. Measurements in three models of tissue injury including drug toxicity, artery occlusion, and acute hyperglycemia were used to test the efficacy of this system. With this hybrid apparatus, a series of structured light patterns at low and high spatial frequencies are projected onto the tissue surface and diffuse reflected light is captured by a CCD camera. A six position filter wheel, equipped with four bandpass filters centered at wavelengths of 650, 690, 800 and 880 nm is placed in front of the camera. Then, light patterns are blocked and a laser source at 650 nm illuminates the tissue while the diffusely reflected light is captured by the camera through the two remaining open holes in the wheel. In this manner, near‐infrared (NIR) and laser speckle images are captured and stored together in the computer for off‐line processing to reconstruct the tissue's properties. Spatial patterns are used to differentiate the effects of tissue scattering from those of absorption, allowing accurate quantification of tissue hemodynamics and morphology, while a coherent light source is used to study blood flow changes, a feature which cannot be measured with the NIR structured light. This combined configuration utilizes the strengths of each system in a complementary way, thus collecting a larger range of sample properties. In addition, once the flow and hemodynamics are measured, tissue oxygen metabolism can be calculated, a property which cannot be measured independently. Therefore, this merged platform can be considered a multiparameter wide‐field imaging and spectroscopy modality. Overall, experiments demonstrate the capability of this spatially coregistered imaging setup to provide complementary, useful information of various tissue metrics in a simple and noncontact manner, making it attractive for use in a variety of biomedical applications.

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Section: Methodsmentioning

confidence: 99%

Section: Lsi Image Analysismentioning

confidence: 99%

Multiparameter wide‐field integrated optical imaging system‐based spatially modulated illumination and laser speckles in model of tissue injuries

Bloygrund

Franjy-Tal

Rosenzweig

et al. 2019

Journal of Biophotonics

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“…assess large surfaces, offering rapid and high-resolution 2-D blood perfusion images. 15 It has been used to evaluate the blood perfusion of wounds, 16 brain, 17 retina, 18 skin, 19 and digestive system. 20 Therefore, the aim of this study was to evaluate the blood perfusion of hypertrophic scars and keloids through LSCI.…”

Section: Lsci Is a Noncontact Perfusion Monitoring Technique That Canmentioning

confidence: 99%

Blood perfusion in hypertrophic scars and keloids studied by laser speckle contrast imaging

Yang

Liu

Yang

et al. 2021

Skin Research and Technology

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Keloid and hypertrophic scars are fibroproliferative lesions of unknown etiology. 1 They can be cosmetically disfiguring, functionally impaired, and emotionally distressing for patients. 2 Vascularization may have an effect on scar pathogenesis, and blood perfusion is a determinant of a scar's physiological condition. 3,4 Although many studies reported on the vascularization of keloids and hypertrophic scars, the conclusions are inconsistent. 1,[5][6][7][8][9][10][11] The reason for this is that most of the existing studies are on the number of blood vessels, but both hypertrophic scars and keloids exhibit vascular endothelial hyperplasia, lumen stenosis, and even occlusion. 6,12 Hence, the number of blood vessels may not accurately reflect the blood perfusion of scars. In addition, some studies did not consider the

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“…Interestingly, along with image registration, Packer and colleagues used microscope parts that moved the optical path relative to the sample to reduce the impact of motion artefacts (Gulati et al ., 2017). This paradigm is also common in portable‐microscope systems that fix fibre‐based and integrated microscopes to the animal's head, thereby allowing for behavioural testing of the mice during imaging, since they are not head‐restrained and can move freely (Ghosh et al ., 2011; Helmchen et al ., 2013; Ziv et al ., 2013; Chen et al ., 2018). Moreover, integrated microscopes with light‐emitting diode (LED) illumination and a large depth of field, enable experimenters to perform video‐rate image acquisition of extensive fields of view with fewer effects from motion artefacts (Ziv et al ., 2013).…”

Section: Animal Restraint and Tissue Immobilizationmentioning

confidence: 99%

Multiphoton intravital microscopy in small animals: motion artefact challenges and technical solutions

Soulet

Lamontagne‐Proulx

Aubé

et al. 2020

Journal of Microscopy

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Summary Since its invention 29 years ago, two‐photon laser‐scanning microscopy has evolved from a promising imaging technique, to an established widely available imaging modality used throughout the biomedical research community. The establishment of two‐photon microscopy as the preferred method for imaging fluorescently labelled cells and structures in living animals can be attributed to the biophysical mechanism by which the generation of fluorescence is accomplished. The use of powerful lasers capable of delivering infrared light pulses within femtosecond intervals, facilitates the nonlinear excitation of fluorescent molecules only at the focal plane and determines by objective lens position. This offers numerous benefits for studies of biological samples at high spatial and temporal resolutions with limited photo‐damage and superior tissue penetration. Indeed, these attributes have established two‐photon microscopy as the ideal method for live‐animal imaging in several areas of biology and have led to a whole new field of study dedicated to imaging biological phenomena in intact tissues and living organisms. However, despite its appealing features, two‐photon intravital microscopy is inherently limited by tissue motion from heartbeat, respiratory cycles, peristalsis, muscle/vascular tone and physiological functions that change tissue geometry. Because these movements impede temporal and spatial resolution, they must be properly addressed to harness the full potential of two‐photon intravital microscopy and enable accurate data analysis and interpretation. In addition, the sources and features of these motion artefacts are varied, sometimes unpredictable and unique to specific organs and multiple complex strategies have previously been devised to address them. This review will discuss these motion artefacts requirement and technical solutions for their correction and after intravital two‐photon microscopy.

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Laser speckle contrast imaging of blood flow in the deep brain using microendoscopy

Cited by 27 publications

References 28 publications

Multiparameter wide‐field integrated optical imaging system‐based spatially modulated illumination and laser speckles in model of tissue injuries

Multiparameter wide‐field integrated optical imaging system‐based spatially modulated illumination and laser speckles in model of tissue injuries

Blood perfusion in hypertrophic scars and keloids studied by laser speckle contrast imaging

Multiphoton intravital microscopy in small animals: motion artefact challenges and technical solutions

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