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Laser speckle contrast imaging

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https://www.readbyqxmd.com/read/30120827/visualization-of-skin-microvascular-dysfunction-of-type-1-diabetic-mice-using-in-vivo-skin-optical-clearing-method
#1
Wei Feng, Rui Shi, Chao Zhang, Shaojun Liu, Tingting Yu, Dan Zhu
To realize visualization of the skin microvascular dysfunction of type 1 diabetic mice, we combined laser speckle contrast imaging and hyperspectral imaging to simultaneously monitor the noradrenaline (NE)-induced responses of vascular blood flow and blood oxygen with the development of diabetes through optical clearing skin window. The main results showed that venous and arterious blood flow decreased without recovery after injection of NE; furthermore, the decrease of arterious blood oxygen induced by NE greatly weakened, especially for 2- and 4-week diabetic mice...
August 2018: Journal of Biomedical Optics
https://www.readbyqxmd.com/read/30067682/selective-photoactivation-of-neural-activity-combined-with-laser-speckle-imaging-of-cerebral-blood-flow
#2
Dong Wen, Yangyang Li, Xuan Zhu, Ming Chen, Jinling Lu, Pengcheng Li
Neural activity leads to alterations in cerebral blood flow (CBF), i.e., neurovascular regulation, which is implicated in brain physiology and pathology. Here a method for simultaneous imaging of CBF and spatially selective photoactivation of neural activity is proposed. CBF was obtained by laser speckle contrast imaging, and a liquid-crystal spatial light modulator (LC-SLM) was used to generate photoactivation patterns targeting designated locations in the cortex. Animal experiments stimulating defined cortical regions of VGAT-ChR2 and wild-type mice were conducted, and experiments with low-intensity stimulation were performed to investigate the influence of background light produced by the LC-SLM...
August 1, 2018: Optics Letters
https://www.readbyqxmd.com/read/30019494/strong-cytoskeleton-activity-on-millisecond-timescales-upon-particle-binding-revealed-by-rocs-microscopy
#3
Felix Jünger, Alexander Rohrbach
Cells change their shape within seconds, cellular protrusions even on subsecond timescales enabling various responses to stimuli of approaching bacteria, viruses or pharmaceutical drugs. Typical response patterns are governed by a complex reorganization of the actin cortex, where single filaments and molecules act on even faster timescales. These dynamics have remained mostly invisible due to a superposition of slow and fast motions, but also due to a lack of adequate imaging technology. Whereas fluorescence techniques require too long integration times, novel coherent techniques such as ROCS microscopy can achieve sufficiently high spatiotemporal resolution...
July 17, 2018: Cytoskeleton
https://www.readbyqxmd.com/read/30003500/large-vessel-vasospasm-is-not-associated-with-cerebral-cortical-hypoperfusion-in-a-murine-model-of-subarachnoid-hemorrhage
#4
Axel Neulen, Simon Meyer, Andreas Kramer, Tobias Pantel, Michael Kosterhon, Svenja Kunzelmann, Hermann Goetz, Serge C Thal
Clinical studies on subarachnoid hemorrhage (SAH) have shown discrepancies between large vessel vasospasm, cerebral perfusion, and clinical outcome. We set out to analyze the contribution of large vessel vasospasm to impaired cerebral perfusion and neurological impairment in a murine model of SAH. SAH was induced in C57BL/6 mice by endovascular filament perforation. Vasospasm was analyzed with microcomputed tomography, cortical perfusion by laser SPECKLE contrast imaging, and functional impairment with a quantitative neuroscore...
July 12, 2018: Translational Stroke Research
https://www.readbyqxmd.com/read/29952071/enhancing-vascular-visualization-in-laser-speckle-contrast-imaging-of-blood-flow-using-multi-focus-image-fusion
#5
Wenzhi Lv, Yang Wang, Xiao Chen, Xiaoxi Fu, Jinling Lu, Pengcheng Li
Laser speckle contrast imaging (LSCI) is a full-field optical imaging method for monitoring blood flow and vascular morphology with high spatiotemporal resolution. However, due to the limited depth of field of optical system, it is difficult to capture a clear blood flow image with all blood vessels focused, especially for the non-planar biological tissues. In this paper, a multi-focus image fusion method based on contourlet transform is introduced to reduce the misfocus effects in LSCI. The experimental results suggest that this method can provide an all-in-focus blood flow image, which is convenient to observe the blood vessels...
June 28, 2018: Journal of Biophotonics
https://www.readbyqxmd.com/read/29916025/short-term-weight-loss-reverses-obesity-induced-microvascular-endothelial-dysfunction
#6
Tamas Csipo, Gabor A Fulop, Agnes Lipecz, Stefano Tarantini, Tamas Kiss, Priya Balasubramanian, Anna Csiszar, Zoltan Ungvari, Andriy Yabluchanskiy
Obesity is one of the major risk factors for cardiovascular diseases and its prevalence is increasing in all age groups, with the biggest impact observed in middle-aged and older adults. A critical mechanism by which obesity promotes vascular pathologies in these patients involves impairment of endothelial function. While endothelial dysfunction in large vessels promotes atherogenesis, obesity-induced microvascular endothelial dysfunction impairs organ perfusion and thereby is causally related to the pathogenesis of ischemic heart disease, chronic kidney disease, intermittent claudication, exercise intolerance, and exacerbates cognitive decline in aging...
June 18, 2018: GeroScience
https://www.readbyqxmd.com/read/29905695/elastography-with-low-frame-rate-laser-speckle-contrast-imaging-using-the-aliasing-effect
#7
Xiao Chen, Jinling Lu, Pengcheng Li
Elastography is an attractive technique for quantifying the mechanical properties of biological tissue. Here, we report an elastography method with low-frame-rate laser speckle contrast imaging (LSCI) using the aliasing effect. This method needs only one excitation source, a low-frame-rate camera, and no synchronization between excitation and acquisition. The accuracy of the elasticity measurement was validated on tissue-mimicking phantoms by comparing the value with the elasticity measured by a high-frame-rate LSCI and by the rheometer...
June 15, 2018: Optics Letters
https://www.readbyqxmd.com/read/29901424/phenotyping-the-microvasculature-in-critical-sized-calvarial-defects-via-multimodal-optical-imaging
#8
Adam Mendez, Alexandra N Rindone, Namrata Batra, Pegah Abbasnia, Janaka Senarathna, Stacy Gil, Darian Hadjiabadi, Warren L Grayson, Arvind P Pathak
Tissue-engineered scaffolds are a powerful means of healing craniofacial bone defects arising from trauma or disease. Murine models of critical-sized bone defects are especially useful in understanding the role of microenvironmental factors such as vascularization on bone regeneration. Here, we demonstrate the capability of a novel multimodality imaging platform capable of acquiring in vivo images of microvascular architecture, microvascular blood flow, and tracer/cell tracking via intrinsic optical signaling (IOS), laser speckle contrast (LSC), and fluorescence (FL) imaging, respectively, in a critical-sized calvarial defect model...
July 2018: Tissue Engineering. Part C, Methods
https://www.readbyqxmd.com/read/29900205/data-set-characterizing-the-systemic-alterations-of-microvascular-reactivity-and-capillary-density-in-patients-presenting-with-infective-endocarditis
#9
Eduardo Tibirica, Amanda Barcelos, Cristiane Lamas
This article represents data associated with a prior publication from our research group, under the title: Evaluation of microvascular endothelial function and capillary density in patients with infective endocarditis using laser speckle contrast imaging and video-capillaroscopy [1]. Patients with definite infective endocarditis, under stable clinical conditions, were prospectively included. The clinical and laboratory features are presented for each of them in raw form. Microvascular reactivity was evaluated using a laser speckle contrast imaging (LSCI) system with a laser wavelength of 785 nm...
June 2018: Data in Brief
https://www.readbyqxmd.com/read/29877342/precision-of-polarimetric-orthogonal-state-contrast-estimation-in-coherent-images-corrupted-by-speckle-poisson-and-additive-noise
#10
Jan Dupont, Matthieu Boffety, François Goudail
We consider laser-illuminated active polarimetric imaging systems that measure the orthogonal state contrast (OSC), a frequently used surrogate to the degree of polarization, that can be used, for example, to discriminate manmade objects from natural backgrounds in remote sensing. We investigate the estimation precision of the OSC parameter in the presence of speckle, Poisson, and additive noise by using the Cramer-Rao lower bound (CRLB). Using Monte Carlo simulations and optical experiments, we show that the expression of the CRLB models the actual OSC estimation performance with excellent accuracy...
June 1, 2018: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
https://www.readbyqxmd.com/read/29794702/supportive-use-of-adipose-derived-stem-cells-in-cell-assisted-lipotransfer-for-localized-scleroderma
#11
Bo Chen, Xiaojun Wang, Xiao Long, Mingzi Zhang, Jiuzuo Huang, Nanze Yu, Jing Xu
BACKGROUND: The authors aimed to analyze factors related to lipotransfer for localized scleroderma, and to explore the feasibility of cell-assisted lipotransfer for localized scleroderma treatment. METHODS: Abdominal fat samples were taken from six scleroderma patients without corticosteroid therapy, five scleroderma patients with corticosteroid therapy, and 10 normal liposuction patients. Their quantity, morphology, and proliferation ability were measured. Blood flow was measured by laser speckle contrast imaging in localized scleroderma lesions and normal contralateral regions for eight localized scleroderma patients...
June 2018: Plastic and Reconstructive Surgery
https://www.readbyqxmd.com/read/29753516/is-endothelial-microvascular-function-equally-impaired-among-patients-with-chronic-chagas-and-ischemic-cardiomyopathy
#12
Juliana Pereira Borges, Fernanda de Souza Nogueira Sardinha Mendes, Gabriella de Oliveira Lopes, Andréa Silvestre de Sousa, Mauro Felippe Felix Mediano, Eduardo Tibiriçá
BACKGROUND: Chronic Chagas cardiomyopathy (CCC) and cardiomyopathies due to other etiologies involve differences in pathophysiological pathways that are still unclear. Systemic microvascular abnormalities are associated with the pathogenesis of ischemic heart disease. However, systemic microvascular endothelial function in CCC remains to be elucidated. Thus, we compared the microvascular endothelial function of patients presenting with CCC to those with ischemic cardiomyopathy disease...
August 15, 2018: International Journal of Cardiology
https://www.readbyqxmd.com/read/29740276/cortical-hemodynamic-responses-under-focused-ultrasound-stimulation-using-real-time-laser-speckle-contrast-imaging
#13
Yi Yuan, Yanchao Zhao, Hongshuai Jia, Mengyang Liu, Shuo Hu, Yingwei Li, Xiaoli Li
Although there is increasing use of focused ultrasound stimulation (FUS) in brain studies, the real-time changes of the cerebral blood flow (CBF) due to FUS remain unclear. In this study, we developed a novel scheme combining FUS and laser speckle contrast imaging, which can be used to measure the CBF caused by FUS in real time. The results showed that the change of CBF increased from 0 to 30 s and reached up to the maximum of 115.1 ± 6.5% at 30 s and then decreased gradually from 30 to 60 s. This study demonstrates that FUS was able to increase CBF and alter cortical hemodynamic responses, which indicates that FUS is a potential non-invasive method to study ischemic stroke rehabilitation...
2018: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/29728943/detection-of-white-spot-lesions-by-segmenting-laser-speckle-images-using-computer-vision-methods
#14
Luciano G Gavinho, Sidnei A Araujo, Sandra K Bussadori, João V P Silva, Alessandro M Deana
This paper aims to develop a method for laser speckle image segmentation of tooth surfaces for diagnosis of early stages caries. The method, applied directly to a raw image obtained by digital photography, is based on the difference between the speckle pattern of a carious lesion tooth surface area and that of a sound area. Each image is divided into blocks which are identified in a working matrix by their χ2 distance between block histograms of the analyzed image and the reference histograms previously obtained by K-means from healthy (h_Sound) and lesioned (h_Decay) areas, separately...
May 5, 2018: Lasers in Medical Science
https://www.readbyqxmd.com/read/29705753/high-intensity-interval-training-or-continuous-training-combined-or-not-with-fasting-in-obese-or-overweight-women-with-cardiometabolic-risk-factors-study-protocol-for-a-randomised-clinical-trial
#15
Andrea De Lorenzo, Diogo Van Bavel, Roger de Moraes, Eduardo V Tibiriça
INTRODUCTION: Physical inactivity and increased caloric intake play important roles in the pathophysiology of obesity. Increasing physical activity and modifying eating behaviours are first-line interventions, frequently hampered by lack of time to exercise and difficulties in coping with different diets. High-intensity interval training (HIIT) may be a time-efficient method compared with moderate-intensity continuous training (CT). Conversely, diets with a fasting component may be more effective than other complex and restrictive diets, as it essentially limits caloric intake to a specified period without major diet composition changes...
April 28, 2018: BMJ Open
https://www.readbyqxmd.com/read/29701760/optical-techniques-for-perfusion-monitoring-of-the-gastric-tube-after-esophagectomy-a-review-of-technologies-and-thresholds
#16
S M Jansen, D M de Bruin, M I van Berge Henegouwen, S D Strackee, D P Veelo, T G van Leeuwen, S S Gisbertz
Anastomotic leakage is one of the most severe complications after esophageal resection with gastric tube reconstruction. Impaired perfusion of the gastric fundus is seen as the main contributing factor for this complication. Optical modalities show potential in recognizing compromised perfusion in real time, when ischemia is still reversible. This review provides an overview of optical techniques with the aim to evaluate the (1) quantitative measurement of change in perfusion in gastric tube reconstruction and (2) to test which parameters are the most predictive for anastomotic leakage...
June 1, 2018: Diseases of the Esophagus: Official Journal of the International Society for Diseases of the Esophagus
https://www.readbyqxmd.com/read/29668909/effect-of-ephedrine-on-gastric-conduit-perfusion-measured-by-laser-speckle-contrast-imaging-after-esophagectomy-a-prospective-in-vivo-cohort-study
#17
S M Jansen, D M de Bruin, M I van Berge Henegouwen, P R Bloemen, S D Strackee, D P Veelo, T G van Leeuwen, S S Gisbertz
Compromised perfusion due to ligation of arteries and veins in esophagectomy with gastric tube reconstruction often (5-20%) results in necrosis and anastomotic leakage, which relate to high morbidity and mortality (3-4%). Ephedrine is used widely in anesthesia to treat intraoperative hypotension and may improve perfusion by the increase of cardiac output and mean arterial pressure (MAP). This study tests the effect of ephedrine on perfusion of the future anastomotic site of the gastric conduit, measured by laser speckle contrast imaging (LSCI)...
April 13, 2018: Diseases of the Esophagus: Official Journal of the International Society for Diseases of the Esophagus
https://www.readbyqxmd.com/read/29616266/laser-inscription-of-pseudorandom-structures-for-microphotonic-diffuser-applications
#18
Tawfiq Alqurashi, Abdulla Alhosani, Mahmoud Dauleh, Ali K Yetisen, Haider Butt
Optical diffusers provide a solution for a variety of applications requiring a Gaussian intensity distribution including imaging systems, biomedical optics, and aerospace. Advances in laser ablation processes have allowed the rapid production of efficient optical diffusers. Here, we demonstrate a novel technique to fabricate high-quality glass optical diffusers with cost-efficiency using a continuous CO2 laser. Surface relief pseudorandom microstructures were patterned on both sides of the glass substrates...
April 19, 2018: Nanoscale
https://www.readbyqxmd.com/read/29607217/modern-diagnostic-techniques-for-the-assessment-of-ocular-blood-flow-in-myopia-current-state-of-knowledge
#19
REVIEW
Ewa Grudzińska, Monika Modrzejewska
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)...
2018: Journal of Ophthalmology
https://www.readbyqxmd.com/read/29601035/simultaneous-viscosity-and-elasticity-measurement-using-laser-speckle-contrast-imaging
#20
Xiao Chen, Yang Wang, Jinling Lu, Pengcheng Li
Viscosity and elasticity are closely related to the physiological characteristics of biological tissues. This Letter reports a simultaneous quantitative measurement of these parameters realized with the laser speckle contrast imaging method. The propagation of a Rayleigh wave induced by an acoustic speaker is traced, and the frequency-dependent velocity dispersion is extracted with the frequency-wavenumber spectrum analysis method. The viscosity and elasticity moduli of oil-in-gelatin tissue-mimicking phantoms are calculated by fitting the dispersion curves to the Voigt model...
April 1, 2018: Optics Letters
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