Triple Spectral Line Imaging of Whole-Body Human Skin: Equipment, Image Processing, and Clinical Data.

Multispectral imaging can provide objective quantitative data on various clinical pathologies, e.g., abnormal content of bio-substances in human skin.

Contactless photoplethysmography for assessment of small fiber neuropathy.

Chronic pain is a prevalent condition affecting approximately one-fifth of the global population, with significant impacts on quality of life and work productivity. Small fiber neuropathies are a common cause of chronic pain, and current diagnostic methods rely on subjective self-assessment or invasive skin biopsies, highlighting the need for objective noninvasive assessment methods. The study aims to develop a modular prototype of a contactless photoplethysmography system with three spectral bands (420, 540, and 800 nm) and evaluate its potential for assessing peripheral neuropathy patients via a skin topical heating test and spectral analyses of cutaneous flowmotions.

Multimodal Approach of Optical Coherence Tomography and Raman Spectroscopy Can Improve Differentiating Benign and Malignant Skin Tumors in Animal Patients.

As in humans, cancer is one of the leading causes of companion animal mortality. Up to 30% of all canine and feline neoplasms appear on the skin or directly under it. There are only a few available studies that have investigated pet tumors by biophotonics techniques.

Microvascular blood flow changes of the abductor pollicis brevis muscle during sustained static exercise.

A practical assessment of the general health and microvascular function of the palm muscle, abductor pollicis brevis (APB), is important for the diagnosis of different conditions. In this study, we have developed a protocol and a probe to study microvascular blood flow using near-infrared diffuse correlation spectroscopy (DCS) in APB during and after thumb abduction at 55% of maximum voluntary contraction (MVC). Near-infrared time resolved spectroscopy (TRS) was also used to characterize the baseline optical and hemodynamic properties.

Remote Photoplethysmography for Evaluation of Cutaneous Sensory Nerve Fiber Function.

About 2% of the world's population suffers from small nerve fiber dysfunction, neuropathy, which can result in severe pain. This condition is caused by damage to the small nerve fibers and its assessment is challenging, due to the lack of simple and objective diagnostic techniques. The present study aimed to develop a contactless photoplethysmography system using simple instrumentation, for objective and non-invasive assessment of small cutaneous sensory nerve fiber function.

Remitted photon path lengths in human skin: measurement data.

The remitted photon path lengths in human skin can be estimated by modelling; however, there are very few experimental data available to validate the simulations. This study exploited the photon time of flight method where picosecond laser pulses at seven wavelength bands in the spectral range 560-800 nm were launched into forearm skin of 10 volunteers via an optical fiber. The pulses of back-scattered light were detected via another optical fiber placed at variable distance (1, 8, 12, 16 or 20 mm) from the input fiber, with subsequent analysis of their shapes for all 35 spectral-spatial combinations.

Relationship of mottling score, skin microcirculatory perfusion indices and biomarkers of endothelial dysfunction in patients with septic shock: an observational study.

Background: In patients with septic shock, the skin is often chosen for the evaluation of peripheral perfusion and oxygenation. Changes in skin microcirculatory vessel oxygen saturation and relative hemoglobin concentration can be described using a mottling score or captured with hyperspectral imaging. However, the effectiveness of the mottling score in assessing microcirculation remains to be shown.

Multimodal Device for Real-Time Monitoring of Skin Oxygen Saturation and Microcirculation Function.

The present study introduces a recently developed compact hybrid device for real-time monitoring of skin oxygen saturation and temperature distribution. The prototype involves a snapshot hyperspectral camera, multi-wavelength illuminator, thermal camera, and built-in computer with custom-developed software. To validate this device in-vivo we performed upper arm vascular occlusion on eight healthy volunteers.

Imaging photoplethysmography for clinical assessment of cutaneous microcirculation at two different depths.

The feasibility of bispectral imaging photoplethysmography (iPPG) system for clinical assessment of cutaneous microcirculation at two different depths is proposed. The iPPG system has been developed and evaluated for in vivo conditions during various tests: (1) topical application of vasodilatory liniment on the skin, (2) skin local heating, (3) arterial occlusion, and (4) regional anesthesia. The device has been validated by the measurements of a laser Doppler imager (LDI) as a reference.

Two-stage multi-Gaussian fitting of conduit artery photoplethysmography waveform during induced unilateral hemodynamic events.

Photoplethysmography (PPG) is an optical technique with high diagnostic potential, yet clinical applications remain underdeveloped. Standardization of signal recording and quantification of waveform are essential prerequisites for broader clinical use. The aim of this study was to utilize a two-stage multi-Gaussian fitting technique in order to examine the parameters of conduit artery PPG waveform recorded during increasing the unilateral regional vascular resistance (RVR).

Effect of probe contact pressure on the photoplethysmographic assessment of conduit artery stiffness.

Currently, photoplethysmography (PPG) is a frequently studied optical blood pulsation detection technique among biophotonic and biomedical researchers due to the fact that it shows high potential for estimating the arterial stiffness (AS). The extraction of diagnostically useful information requires standardized measurement procedure with good repeatability. However, the effects of a crucially important factor-the optimal contact pressure (CP) of the probe-are often ignored.

Finger and ear photoplethysmogram waveform analysis by fitting with Gaussians.

Analysis of the contour of the blood volume pulse (VP) has become important because it contains much information about cardiovascular activity. Traditionally, pulse contour analysis requires first or higher derivatives to be calculated. This paper describes a novel algorithm for analysing simultaneously measured ear and finger photoplethysmography (PPG) signals.