What Remote PPG Oximetry Tells Us about Pulsatile Volume?

While pulse oximetry using remote photoplethysmography (rPPG) is used in medicine and consumer health, sound theoretical foundations for this methodology are not established. Similarly to traditional pulse oximetry, rPPG oximetry uses two wavelengths to calculate the tissue oxygenation using the so-called ratio-of-ratios, . However, the relationship between and tissue oxygenation has not been derived analytically.

Observation of blood motion in the internal jugular vein by contact and contactless photoplethysmography during physiological testing: case studies.

Central venous pressure is an estimate of right atrial pressure and is often used to assess hemodynamic status. However, since it is measured invasively, non-invasive alternatives would be of great utility. The aim of this preliminary study was a) to investigate whether photoplethysmography (PPG) can be used to characterize venous system fluid motion and b) to find the model for venous blood volume modulations.

Observation of Tissue Oxygenation Changes Using Remote Photoplesysmography with a Smartphone.

Background: Tissue oxygenation is a critical marker of tissue status and can be used to evaluate and track wound progress, the viability of transplanted tissue, and burns. Thus, the determination of tissue oxygenation (preferably remotely) is of great importance.

Aim: Explore the impact of oxygenation changes on tissue color.

How Skin Color Depends on Tissue Oxygenation.

Background: Skin color is essential to skin and wound assessment as it brings valuable information about skin physiology and pathology. An approach, which can help deconvolute and isolate various mechanisms affecting skin color, could be helpful to drive the remote photoplethysmography (rPPG) utility beyond its current applications.

Aim: The present work aims to create a simple analytical framework that links skin color with blood oxygenation and perfusion.

Is my wound infected? A study on the use of hyperspectral imaging to assess wound infection.

Introduction: Clinical signs and symptoms (CSS) of infection are a standard part of wound care, yet they can have low specificity and sensitivity, which can further vary due to clinician knowledge, experience, and education. Wound photography is becoming more widely adopted to support wound care. Thermography has been studied in the medical literature to assess signs of perfusion and inflammation for decades.

Feasibility of Skin Water Content Imaging Using CMOS Sensors.

Pressure injuries (PI) result from pressure-induced damage to the skin and underlying tissues. Currently, Stage I PI are detected using visual skin assessments. However, this visual method is unable to detect skin color changes in persons with darkly pigmented skin, which results in a higher Stage II-IV PI incidence and PI-associated mortality in persons with a darker complexion.

Remote Photoplethysmography with a High-Speed Camera Reveals Temporal and Amplitude Differences between Glabrous and Non-Glabrous Skin.

Photoplethysmography (PPG) is a noninvasive optical technology with applications including vital sign extraction and patient monitoring. However, its current use is primarily limited to heart rate and oxygenation monitoring. This study aims to demonstrate the utility of PPG for physiological investigations.

Feasibility Study of Remote Contactless Perfusion Imaging with Consumer-Grade Mobile Camera.

Unlabelled: A non-invasive, contactless, inexpensive and easy-to-operate perfusion imaging method using a consumer-grade mobile camera (iPhone 8) developed in our group can visualise blood flow in tissue.

Methods: Ischemia was induced in one hand using a blood pressure cuff inflated over the systolic blood pressure to stop the blood flow. Using an iPhone, data was collected from 5 subjects, beginning with no occlusion (a baseline), followed by one hand occluded, and then release of the occlusion to restore blood circulation.

Improved Optical Tissue Model for Tissue Oximetry Imaging Applications.

Introduction: Chronic, non-healing wounds are a growing concern in healthcare delivery. Tissue oxygenation is recognised as critical to successful wound healing. However, the quality and quantity of the information extracted by hyperspectral imaging depend on the optical tissue model.

Towards Development of Specular Reflection Vascular Imaging.

Specular reflection from tissue is typically considered as undesirable, and managed through device design. However, we believe that specular reflection is an untapped light-tissue interaction, which can be used for imaging subcutaneous blood flow. To illustrate the concept of subcutaneous blood flow visualization using specular reflection from the skin, we have developed a ray tracing for the neck and identified conditions under which useful data can be collected.

Infrared Thermography in Wound Care, Surgery, and Sports Medicine: A Review.

For many years, the role of thermometry was limited to systemic (core body temperature) measurements (e.g., pulmonary catheter) or its approximation using skin/mucosa (e.

On the Feasibility of Pulse Wave Velocity Imaging for Remote Assessment of Physiological Functions.

Introduction: Pulse wave velocity imaging (PWVi) is a novel technology developed by our group for real-time assessment of ischemia. The objectives of this proof-of-concept study included (1) remote detection of blood flow pulse and (2) assessing the feasibility of pulse wave velocity (PWV) imaging.

Methods: PWVi is based on a 12-bit RGB camera (Basler acA-2000-165uc) capturing videos at up to 1000 fps.

Hyperspectral imaging in wound care: A systematic review.

Multispectral and hyperspectral imaging (HSI) are emerging imaging techniques with the potential to transform the way patients with wounds are cared for, but it is not clear whether current systems are capable of delivering real-time tissue characterisation and treatment guidance. We conducted a systematic review of HSI systems that have been assessed in patients, published over the past 32 years. We analysed 140 studies, including 10 different HSI systems.