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Comparison of different non-invasive diagnostic techniques used for HMME-PDT in the treatment of port wine stains
摘要： 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. Four non-invasive diagnostic techniques including VISIA-CRTM system, dermoscopy, high-frequency ultrasound (HFUS) and laser speckle imager (LSCI) were used to obtain standard radiographic data containing skin color, skin thickness, blood vessel morphology, blood vessel distribution and blood perfusion from lesions and normal skin surrounded before and after HMME-PDT. Results: The standard image pattern of VISIA-CRTM system showed color change of the lesions of PWS after HMME-PDT. RBX-red image of VISIA-CRTM system showed that erythema was highly aggregated even on invisible lesions at baseline but decreased after HMME-PDT. The erythema index reduced value d was related to the efficacy rating (γ=0.631, P＜0.05). Dermoscopy showed that the number of spot-like and irregular linear vessels increased correlated with increase of clinical classification. After HMME-PDT, vascular rupture was observed by dermoscopy. The response rate of lesions with vascular rupture was 100.00% (20/20). And the response rate of lesions without vascular rupture was 63.64% (7/11). Vascular rupture sign was correlated with better efficacy (P＜0.05). High-frequency ultrasound showed that dermis of PWS thickened and arranged loosely with scattered linear hypoechoic signal. After HMME-PDT, the dermal layer of the lesions became thinner with the linear hypoechoic signal decreased. The response rate of lesions with linear hypoechoic signal was 76.92% (10/13), and that without linear hypoechoic signal was 94.44% (17/18). The lesions without linear hypoechoic signal in dermis showed better efficacy (P＜0.05). In some lesions, Laser speckle contrast showed high blood perfusion signal in PWS lesions and a blood perfusion reduction after HMME-PDT. Conclusion: VISIA-CRTM system can be used to observe not only visible but also invisible lesions of PWS. Moreover, lesions fading after HMME-PDT treatment can be described objectively by VISIA-CRTM system. Dermoscopy played an important role in the clinical classification of PWS, including assessing vascular injury after HMME-PDT, guiding the adjustment of therapeutic dose, and selecting the end point of treatment. HFUS and LSCI can be both used to assist the treatment response evaluation of HMME-PDT.
关键词： dermoscopy,port-wine stains,laser speckle contrast imaging,hemoporfin-mediated photodynamic therapy,VISIA-CRTM system,high-frequency ultrasound
更新于2025-09-23 15:23:52
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Using blood flow pulsatility to improve the accuracy of laser speckle contrast imaging in the assessment of burns
摘要： Objectives: Measurement of perfusion is an established method to evaluate the depth of burns. >48 h after injury. The aim of the study was to investigate if measurement of blood flow pulsatility, combined with perfusion measurement, can improve early assessment of burn depth using laser speckle contrast imaging (LSCI). Methods: Perfusion and pulsatility were measured with LSCI in 187 regions of interest in 32 patients, between 0 and 5 days after injury. The reproducibility of pulsatility was tested for recording durations between 1 and 12 s. The most reproducible duration was chosen, and receiver operator characteristics were created to find suitable pulsatility cut-offs to predict surgical need. Results: A measurement duration of 8 s resulted in a good reproducibility of the pulsatility (% CV: 15.9%). Longer measurement durations resulted in a small improvement of the accuracy of the assessment. A pulsatility of <1.45 (Perfusion Units)2 on day 0–2 after injury predicted surgical need with a sensitivity of 100% (95% CI: 83.2–100%), specificity of 100% (95% CI: 95.2–100%), a positive predictive value of 100%, and a negative predictive value of 100%. Pulsatility was not significantly different when comparing measurements done day 0–2 to day 3–5. Perfusion was however significantly higher day 3–5 compared to day 0–2 for wounds healing within 3 weeks. Conclusion: Measurement of pulsatility improves the accuracy of the assessment of burns with LSCI and makes it possible to predict the need for surgery during day 0–2 after injury with a high accuracy.
关键词： Pulsatility,Burn severity,Scalds,Laser speckle contrast imaging,Perfusion,Burn assessment
更新于2025-09-23 15:21:01
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Validating a low-cost laser speckle contrast imaging system as a quantitative tool for assessing retinal vascular function
摘要： The ability to monitor progression of retinal vascular diseases like diabetic retinopathy in small animal models is often complicated by their failure to develop the end-stage complications which characterize the human phenotypes in disease. Interestingly, as micro-vascular dysfunction typically precedes the onset of retinal vascular and even some neurodegenerative diseases, the ability to visualize and quantify hemodynamic changes (e.g. decreased flow or occlusion) in retinal vessels may serve as a useful diagnostic indicator of disease progression and as a therapeutic outcome measure in response to treatment. Nevertheless, the ability to precisely and accurately quantify retinal hemodynamics remains an unmet challenge in ophthalmic research. Herein we demonstrate the ability to modify a commercial fundus camera into a low-cost laser speckle contrast imaging (LSCI) system for contrast-free and non-invasive quantification of relative changes to retinal hemodynamics over a wide field-of-view in a rodent model.
关键词： ophthalmic research,laser speckle contrast imaging,retinal hemodynamics,retinal vascular diseases,diabetic retinopathy
更新于2025-09-23 15:21:01
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Comparison of two skin temperature assessment methods after the application of topical revulsive products: Conductive iButton data logger system vs contact-free infrared thermometry
摘要： Background: Skin temperature assessments comprise conductive and contact-free techniques. Comparison between conductive data loggers and contact-free thermometry after the application of revulsive products is scarce. This study aimed to compare iButton data loggers with an infrared thermometer after the application of two revulsive products. Secondly, the relation between skin temperature kinetics with skin's perfusion of microcirculation was investigated. Materials and methods: Healthy females (n = 25) were randomly allocated to two groups, representing the products A and B. Skin temperature was measured with “iButtons” and an infrared pistol at baseline and up to 1 hour after application. Skin's perfusion of microcirculation was monitored with a laser speckle contrast imager. Results: Baseline “iButton” temperature values were significantly lower compared with infrared pistol values in both groups. After application of the products, skin temperature decreased as recorded with both devices followed by an increase to baseline values when measured with the pistol. The results obtained by the “iButtons” reached values above baseline in both products towards the end of the follow-up period. A moderate correlation was found between infrared pistol and “iButton” system in product A, with a weak negative correlation between skin's perfusion of microcirculation and temperature devices. For product B, the correlation between the devices was moderate and between skin's perfusion and temperature devices weak and positive. Conclusion: Both devices produced similar kinetics, except at baseline, where they may differ as metallic loggers have been insufficiently adapted to skin temperature. Skin's perfusion of microcirculation could not explain skin temperature changes.
关键词： thermocouples,laser speckle contrast imaging,infrared thermography,skin temperature,revulsive products
更新于2025-09-23 15:19:57
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Dilated residual learning with skip connections for real-time denoising of laser speckle imaging of blood flow in a log-transformed domain
摘要： Laser speckle contrast imaging (LSCI) is a wide-field and noncontact imaging technology for mapping blood flow. Although the denoising method based on block-matching and filtering three-dimensional (BM3D) was proposed to improve its signal-to-noise ratio (SNR) significantly, the processing time makes it difficult to realize real-time denoising. Furthermore, it is still difficult to obtain an acceptable level of SNR with a few raw speckle images given the presence of significant noise and artifacts. A feed-forward denoising convolutional neural network (DnCNN) achieves state-of-the-art performance in denoising nature images and is efficiently accelerated by GPU. However, it performs poorly in learning with original speckle contrast images of LSCI owing to the inhomogeneous noise distribution. Therefore, we propose training DnCNN for LSCI in a log-transformed domain to improve training accuracy and it achieves an improvement of 5.13 dB in the peak signal-to-noise ratio (PSNR). To decrease the inference time and improve denoising performance, we further propose a dilated deep residual learning network with skip connections (DRSNet). The image-quality evaluations of DRSNet with five raw speckle images outperform that of spatially average denoising with 20 raw speckle images. DRSNet takes 35 ms (i.e., 28 frames per second) for denoising a blood flow image with 486 × 648 pixels on an NVIDIA 1070 GPU, which is approximately 2.5 times faster than DnCNN. In the test sets, DRSNet also improves 0.15 dB in the PSNR than that of DnCNN. The proposed network shows good potential in real-time monitoring of blood flow for biomedical applications.
关键词： Blood flow,convolutional neural network (CNN),laser speckle contrast imaging (LSCI),dilated convolution,skip connection
更新于2025-09-16 10:30:52
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Depth of Field Extension in Laser Speckle Contrast Imaging
摘要： A new technique that can increase the depth of field (DOF) for in vivo tissue imaging is presented. Extended DOF for the imaging of strongly scattering media is realized through combining laser speckle contrast imaging (LSCI) with light field (LF) microscopy. To the best of our knowledge, it is for the first time to combine these two imaging techniques into one system to provide enhanced functionality. The entire imaging process requires only one single detection with no mechanical adjustment involved. The feasibility and capability of the proposed technique is experimentally demonstrated in volumetric flow speed measurement.
关键词： laser speckle contrast imaging,Light field,depth of field
更新于2025-09-16 10:30:52
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[IEEE 2019 41st Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC) - Berlin, Germany (2019.7.23-2019.7.27)] 2019 41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - A prototype system of portable laser speckle imager based on embedded graphics processing unit platform
摘要： Laser speckle contrast imaging (LSCI) is a high-resolution full-field optical technique for measuring blood flow, which has been widely used in clinical and biomedical research. However, most of the current LSCI instruments are bulky, limiting their application settings. In this work, we proposed a prototype system of portable laser speckle imager. Different from the desktop laser speckle systems that utilize personal computer (PC), our system was designed with embedded GPU system (Jetson TX2, NVIDIA, USA) and a LCD touch screen (16.5 × 12.4 cm in size, 380 g in weight). In-vivo experiments showed that the portable GPU-based system had comparable performance with our laboratory LSCI system. Such a portable LSCI imager could be potentially used in a situation that requires for easy operation and installation, such as intraoperative monitoring or bedside diagnosis.
关键词： Laser speckle contrast imaging,portable,blood flow,embedded GPU,real-time monitoring
更新于2025-09-12 10:27:22
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Use of Laser Speckle Contrast Imaging for Successful Fingertip Replantation
摘要： Fingertip replantation is a technical challenge for microsurgeons. For successful fingertip replantation, it is important to monitor the replanted fingertip vascularity for the early detection and revision of vascular compromise. Laser speckle contrast imaging (LSCI) is a camera-based technique that measures the perfusion by illuminating the tissue with a 785-nm-wavelength divergent laser beam. This creates a speckle pattern over the illuminated area. We present a case in which postoperative monitoring of the replanted fingertip microcirculation using LSCI allowed for successful Tamai zone I fingertip replantation. Postoperative monitoring using LSCI has 3 main advantages. First, this method is harmless to the patient and the replanted fingertip. A camera-based technique enables microcirculation monitoring without touching the patient or the replanted fingertip. Second, tissue perfusion is measured in real time and recorded continuously, allowing for the rapid response to the arterial or venous occlusion to be observed. Third, using LSCI, the skin perfusion can be measured quantitatively. Although further clinical investigations will be required to confirm its efficacy, LSCI has the potential to be a useful monitoring device.
关键词： fingertip replantation,microcirculation monitoring,Laser speckle contrast imaging
更新于2025-09-12 10:27:22
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Laser-based Techniques for Microcirculatory Assessment in Orthopedics and Trauma Surgery
摘要： Microcirculatory integrity and proper function are the cornerstones to tissue nourishment and viability. In the clinical environment extended immobility, injuries, and inflammatory reactions demand local microcirculatory adaption to provide adequate supply. Assessment of endothelial adjustment capability and microcirculatory perfusion status, as direct or surrogate markers of disease, are therefore of uttermost interest to the treating physician. Given the simple, noninvasive, nonradiating nature of laser-based techniques for bedside or intraoperative microcirculatory perfusion assessment, this article’s objective is to present a comprehensive overview of available techniques, their technological aspects, and current application. Advantages of individual methods are pointed out and compared with each other. The areas of medical utilization relevant to orthopedics and trauma surgery are exemplified and their available evidence elaborated. A particular focus is put on laser speckle contrast imaging, with its current and future influence on medical practice.
关键词： noninvasive cutaneous microcirculatory perfusion assessment,laser Doppler flowmetry,laser Doppler imaging,Laser speckle contrast imaging
更新于2025-09-11 14:15:04
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Wavelet Analysis of the Temporal Dynamics of the Laser Speckle Contrast in Human Skin
摘要： Objective: Spectral analysis of laser Doppler ?owmetry (LDF) signals has been widely used in studies of physiological vascular function regulation. An alternative to LDF is the laser speckle contrast imaging method (LSCI), which is based on the same physical principle. In contrast to LDF, LSCI provides non-scanning full-?eld imaging of a relatively wide skin area and offers high spatial and temporal resolutions, which allows visualization of microvascular structure. This circumstance, together with a large number of works which had shown the effectiveness of temporal LSCI analysis, gave impetus to experimental studies of the relation between LDF and LSCI used to monitor the temporal dynamics of blood ?ow. Methods: Continuous wavelet transform was applied to construct a time-frequency representation of a signal. Results: Analysis of 10 minute LDF and LSCI output signals recorded simultaneously revealed rather high correlation between oscillating components. It was demonstrated for the ?rst time that the spectral energy of oscillations in the 0.01-2 Hz frequency range of temporal LSCI recordings carries the same information as the conventional LDF recordings and hence it re?ects the same physiological vascular tone regulation mechanisms. Conclusion: The approach proposed can be used to investigate speckle pattern dynamics by LSCI in both normal and pathological conditions. Signi?cance: The results of research on the in?uence of spatial binning and averaging on the spectral characteristics of perfusion monitored by LSCI are of considerable interest for the development of LSCI systems optimized to evaluate temporal dynamics.
关键词： laser Doppler ?owmetry,oscillations,blood microcirculation,wavelets,laser speckle contrast imaging
更新于2025-09-11 14:15:04