Read by QxMD icon Read

Laser speckle contrast imaging

Yuemei Zhao, Yanbai Xue, Yan Zhang, Weitao Li, Zhiy Qian
In vivo simultaneous monitoring of blood flow and changes of concentration of oxyhemoglobin (ΔHbO2 ) in brain is a key important method for the research of cerebrovascular disease. In this study, a new monitoring system, combining laser speckle contrast imaging method and spectral analysis method, was proposed, which could be utilized to measure the cerebral blood flow and ΔHbO2 on mice during traumatic brain injury. The principle of the present system was studied and the hardware platform of the detection system was built...
January 30, 2019: Zhongguo Yi Liao Qi Xie za Zhi, Chinese Journal of Medical Instrumentation
Jin-Hui Yoon, Yong Jeong
Connections between various cell types in the brain enable cognitive function. The neurovascular unit is a structure composed of different cell types that regulate neurovascular coupling, blood-brain barrier permeability, and other interactions with peripheral systems. The relationship among the components of the neurovascular unit is complex and difficult to study without the use of in vivo neurovascular disease imaging. In this review, we introduce principles and examples of various in vivo optical imaging techniques including laser Doppler flowmetry, laser speckle contrast imaging, intrinsic optical signal imaging, optical coherence tomography, and two-photon microscopy...
February 11, 2019: Archives of Pharmacal Research
Eugene B Postnikov, Maria O Tsoy, Polina A Timoshina, Dmitry E Postnov
The laser speckle contrast analysis (LASCA) is one of the most applicable tools in microcirculation studies. While the basic idea, as well as experimental setup for this method, are fairly simple, there is still the room for advancing of data processing algorithms. Specifically, the conventional realizations of LASCA method may limit the spatial and/or temporal resolution and thus fail in the detection of very small contrast objects since they based on the fixed-size rectangular sliding window function. We suggest an alternative data processing algorithm based on the usage of the Gaussian sliding filter for a sequential determination of both spatial and temporal parts of the speckle contrast...
February 8, 2019: International Journal for Numerical Methods in Biomedical Engineering
Weimin Cheng, Xuan Zhu, Xiao Chen, Miaowen Li, Jinling Lu, Pengcheng Li
Laser speckle contrast imaging (LSCI) is a full-field, noncontact imaging technology for mapping blood flow with high spatio-temporal resolution, in which the speckle contrast can be estimated either in spatial domain or temporal domain. Temporal laser speckle contrast imaging (tLSCI) provides higher spatial resolution than spatial domain does. However, when the number of sampling frames is limited, it is difficult to obtain accurate blood flow velocity owing to the significant statistical noise. The widely used spatially averaged tLSCI (savg-tLSCI) usually requires a large number of sampling frames to obtain acceptable denoising performance...
January 29, 2019: IEEE Transactions on Medical Imaging
Johan Zötterman, Erik Tesselaar, Simon Farnebo
BACKGROUND: We evaluated the use of laser speckle contrast imaging (LSCI) in the perioperative planning in reconstructive flap surgery. The aim of the study was to investigate whether LSCI can predict regions with a high risk of developing postoperative necrosis. Our hypothesis was that, perioperatively, such regions have perfusion values below a threshold value and show a negative perfusion trend. METHODS: A porcine flap model based on the cranial gluteal artery perforator was used...
January 3, 2019: Journal of Plastic, Reconstructive & Aesthetic Surgery: JPRAS
Thierry Paquette, Ryota Tokunaga, Sara Touj, Hugues Leblond, Mathieu Piché
Cerebral blood flow (CBF) is essential for neuronal metabolic functions. CBF is partly regulated by cholinergic projections from the nucleus basalis of Meynert (NBM) during cortical processing of sensory information. During pain-related processing, however, this mechanism may be altered by large fluctuations in systemic mean arterial pressure (MAP). The objective of this study was to investigate the contribution of NBM to CBF responses evoked by nociceptive electrical stimuli and how it may be affected by systemic MAP...
January 31, 2019: Neuroscience Research
Anthony J Deegan, Ruikang Ricky Wang
Despite our understanding that the microvasculature plays a multifaceted role in the development and progression of various conditions, we know little about the extent of this involvement. A need exists for non-invasive, clinically meaningful imaging modalities capable of elucidating microvascular information to aid in our understanding of disease, and to aid in the diagnosis/monitoring of disease for more patient-specific care. In this review article, a number of imaging techniques are summarized that have been utilized to investigate the microvasculature of skin, along with their advantages, disadvantages and future perspectives in preclinical and clinical settings...
February 1, 2019: Physics in Medicine and Biology
Benjamin Lengenfelder, Fanuel Mehari, Martin Hohmann, Markus Heinlein, Erika Chelales, Maximilian J Waldner, Florian Klämpfl, Zeev Zalevsky, Michael Schmidt
Laser surgery is a rising surgical technique, which offers several advantages compared to the traditional scalpel. However, laser surgery lacks a contact-free feedback system which offers high imaging contrast to identify the tissue type ablated and also a high penetration depth. Photoacoustic imaging has the potential to fill this gap. Since photoacoustic detection is commonly contact based, a new non-interferometric detection technique based on speckle-analysis for remote detection is presented in this work...
January 31, 2019: Scientific Reports
Asger Maare Søndergaard, Cathrine Bang Overgaard, Aleksandra Mazur, Dmitry D Postnov, Vladimir Matchkov, Christian Aalkjaer
The prevailing dogma about neurogenic regulation of vascular tone consists of major vasodilation caused by CGRP (and possibly substance P) released from sensory-motor nerves and vasoconstriction caused by noradrenaline, ATP and NPY release from sympathetic nerves. Most studies on perivascular nerve mediated vasodilation are made in vitro. We here provide evidence that in vivo electrical perivascular nerve stimulation in rat mesenteric small arteries causes a large β1-adrenoceptor mediated vasodilation, which contrasts with a smaller vasodilation caused by endogenous CGRP, which is only visible after inhibition of Y1 NPY receptors...
January 29, 2019: Journal of Physiology
Ivo P Torres Filho, David Barraza, Charnae Williams, Kim Hildreth, Michael A Dubick
BACKGROUND: Many studies evaluating blood flow and oxygen partial pressure (PO2) do not directly measure both parameters, are confined to few locations/microvessels, and depend on investigator's selection of measuring sites. Moreover, clinically/physiologically-relevant systemic parameters are not simultaneously recorded. We implemented an automated system for prolonged blood flow/PO2 acquisition in large areas while collecting relevant systemic information. METHODS: In anesthetized animals, cardio-respiratory parameters were continuously recorded...
January 25, 2019: Journal of Trauma and Acute Care Surgery
Reka Fazekas, Eszter Molnár, Barbara Mikecs, Zsolt Lohinai, János Vág
Laser speckle contrast imaging (LSCI) is a novel method for measuring superficial blood perfusion over large areas. Since it is non-invasive and avoids direct contact with the measured area, it is suitable for monitoring blood flow changes during wound healing in human patients. Vestibuloplasty is periodontal surgery to the oral vestibule, aiming to restore vestibular depth with simultaneous enlargement of the keratinized gingiva. In this special clinical case, a split thickness flap was elevated at the first upper premolar and a xenogenic collagen matrix was adapted to the resulting recipient bed...
January 12, 2019: Journal of Visualized Experiments: JoVE
Ingemar Fredriksson, Martin Hultman, Tomas Strömberg, Marcus Larsson
Laser speckle contrast imaging (LSCI) enables video rate imaging of blood flow. However, its relation to tissue blood perfusion is nonlinear and depends strongly on exposure time. By contrast, the perfusion estimate from the slower laser Doppler flowmetry (LDF) technique has a relationship to blood perfusion that is better understood. Multiexposure LSCI (MELSCI) enables a perfusion estimate closer to the actual perfusion than that using a single exposure time. We present and evaluate a method that utilizes contrasts from seven exposure times between 1 and 64 ms to calculate a perfusion estimate that resembles the perfusion estimate from LDF...
January 2019: Journal of Biomedical Optics
Julian M Rüwald, Cornelius Jacobs, Sebastian Scheidt, Christof Burger, Dieter C Wirtz, Frank A Schildberg
MINI: Overview of laser-based techniques for the noninvasive cutaneous microcirculatory perfusion assessment, their technological aspects, comparative advantages, current, and future applications in the field of orthopedic and trauma surgery.This is an open access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal...
January 15, 2019: Annals of Surgery
Johanna Berggren, Kajsa Tenland, Cu Dinh Ansson, Ulf Dahlstrand, Rafi Sheikh, Jenny Hult, Karl Engelsberg, Sandra Lindstedt, Malin Malmsjö
PURPOSE: It has recently been shown that the flap pedicle does not supply blood to a tarsoconjunctival graft in the modified Hughes procedure in patients. This raises questions concerning the rate of revascularization of the free skin graft commonly used to reconstruct the anterior lamella. The aim of this study was, thus, to monitor the course of revascularization in free skin grafts overlying modified Hughes tarsoconjunctival flaps, using laser-based techniques. METHODS: Free skin grafts from the upper eyelid or upper arm in 9 patients were used to cover a tarsoconjunctival flap according to the modified Hughes procedure...
January 18, 2019: Ophthalmic Plastic and Reconstructive Surgery
Karalyn E McRae, Jessica Pudwell, Nichole Peterson, Graeme N Smith
Preeclampsia (PE) is characterized by systemic maternal endothelial dysfunction. Changes in endothelial reactivity have been reported before the onset of clinical signs of PE, and continuing into the post-partum period. Women who smoke during pregnancy have a 33% reduced risk of developing PE. This reduced risk is hypothesized to be, in part, attributed to carbon monoxide (CO), a by-product of cigarette combustion and a known endogenous vasodilator. Determining the vascular effects of CO in healthy women, may inform how CO can improve endothelial function and have promise as a novel therapeutic for PE...
January 15, 2019: Microvascular Research
Wei-Cheng Chang, Ja-Hon Lin, Ting-Yu Liao, Chin-Yi Yang
A noise-like pulse (NLP) with broadband emission spectrum and superior beam quality from a dispersion managed mode-locked Yb-doped fiber laser has been demonstrated based on stimulated Raman scattering. After insertion of a 150 m long single mode fiber into the laser cavity, the second order stoke wave from 1.3 MHz repetition rate of NLP can be excited. With a 320 mW pump power, the highest pulse energy of NLP was about 35.1 nJ and the emission spectrum was extended from 1000 to 1160 nm. Through a multi-mode fiber laser, the broad bandwidth NLP can produce relatively low speckle noise imaging with contrast below 0...
November 26, 2018: Optics Express
Shigehiro Kojima, Tsuguo Sakamoto, Yuko Nagai, Yutaka Matsui, Kyojiro Nambu, Ken Masamune
BACKGROUND: The main limitation of perfusion assessment with indocyanine green fluorescence angiography during colorectal surgery is that the surgeon assesses the quality of perfusion subjectively. The ideal intestinal viability test must be minimally invasive, objective, and reproducible. We evaluated the quantitativity and reproducibility of laser speckle contrast imaging for perfusion assessment during colorectal surgery. METHODS: This was a prospective, nonrandomized, pilot study of 8 consecutive patients who underwent elective left-sided colorectal resection...
January 13, 2019: Surgical Innovation
Janaka Senarathna, Hang Yu, Callie Deng, Alice L Zou, John B Issa, Darian H Hadjiabadi, Stacy Gil, Qihong Wang, Betty M Tyler, Nitish V Thakor, Arvind P Pathak
Neurovascular coupling, cerebrovascular remodeling and hemodynamic changes are critical to brain function, and dysregulated in neuropathologies such as brain tumors. Interrogating these phenomena in freely behaving animals requires a portable microscope with multiple optical contrast mechanisms. Therefore, we developed a miniaturized microscope with: a fluorescence (FL) channel for imaging neural activity (e.g., GCaMP) or fluorescent cancer cells (e.g., 9L-GFP); an intrinsic optical signal (IOS) channel for imaging hemoglobin absorption (i...
January 9, 2019: Nature Communications
Long Wen, Yunfeng Zhang, Linglin Zhang, Xiaojing Liu, Peiru Wang, Shuzhan Shen, Chan Hu, Lehang Guo, Wencai Jiang, Xiuli Wang
BACKGROUND: Hemoporfin-mediated photodynamic therapy (HMME-PDT) is an effective method for treating port wine stains (PWS). While, it still lacks methods to evaluate the treatment of HMME-PDT for PWS effectively and objectively. OBJECTIVE: This study aimed to compare the value of different non-invasive diagnostic techniques used for HMME-PDT treatment evaluation in PWS. METHODS: Thirty-one lesions of 22 patients with PWS were treated with HMME-PDT...
January 6, 2019: Photodiagnosis and Photodynamic Therapy
Yayou Zhang, Liang Zhao, Jiandong Li, Jie Wang, Huijie Yu
OBJECTIVE: Facial nerve palsy (FNP) is a common disease in the otorhinolaryngological department. Besides the main symptom of motionlessness occurring in the ipsilateral facial muscles in FNP, there are other common complaints of numbness, stiffness and tightness in ipsilateral face described by the patients. Based on our pilot study, we further investigated the relevance between these complaints and facial microcirculation. METHOD: Function of facial microcirculation was evaluated by laser speckle contrast imaging (LCSI)...
January 7, 2019: European Archives of Oto-rhino-laryngology
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"