Smartphone-based optical palpation: towards elastography of skin for telehealth applications

Virtual physical examination in teleconsultation: A scoping review

BACKGROUND

The conduct of virtual physical examination has provided significant information for the diagnosis during a teleconsultation session, especially during the COVID-19 pandemic, where in-person physical examinations have been greatly compromised.

OBJECTIVE

The aim of this scoping review was to provide a comprehensive overview of the available evidence concerning virtual physical examination (VPE) in all healthcare settings during the COVID-19 pandemic. The review focuses on types of VPE, technological and non-technological approaches, patient and clinician experiences, as well as barriers and facilitators of VPE.

METHODS

A literature search was conducted across three databases, namely MEDLINE, Embase, and Scopus. Only studies in the English language with primary research data collected from December 2019 to January 2023 were included. A narrative analysis, highlighting patients' and clinicians' experiences, was conducted on the included studies. This scoping review was reported using The PRISMA extension for scoping reviews (PRISMA-ScR) Checklist.

RESULTS

A total of 25 articles meeting eligibility criteria were identified. Three major types of VPE included were musculoskeletal, head and neck, and chest exams. Sixteen studies involved specific technological aids, while three studies involved non-technological aids. Patients found VPE helped them to better assess their disease conditions, or aided their clinicians' understanding of their conditions. Clinicians also reported that VPE had provided enough clinically relevant information for decision-making in 2 neurological evaluations. Barriers to conducting VPE included technological challenges, efficacy concerns, confidence level of assistants, as well as patient health conditions, health literacy, safety, and privacy.

CONCLUSIONS

Patients found virtual physical examination (VPE) helpful in understanding their own conditions, and clinicians found it useful for better assessing patient's conditions. From the clinicians' point of view, VPE provided sufficient clinically relevant information for decision-making in neurological evaluations. Major barriers identified for VPE included technological issues, patient's health conditions, and their health literacy.

The biomechanics of wounds at physiologically relevant levels: Understanding skin's stress-shielding effect for the quantitative assessment of healing

Wounds are responsible for the decrease in quality of life of billions of people around the world. Their assessment relies on subjective parameters which often delays optimal treatments and results in increased healthcare costs. In this work, we sought to understand and quantify how wounds at different healing stages (days 1, 3, 7 and 14 post wounding) change the mechanical properties of the tissues that contain them, and how these could be measured at clinically relevant strain levels, as a step towards quantitative wound tracking technologies. To achieve this, we used digital image correlation and mechanical testing on a mouse model of wound healing to map the global and local tissue strains. We found no significant differences in the elastic and viscoelastic properties of wounded vs unwounded skin when samples were measured in bulk, presumably as these were masked by the protective mechanisms of skin, which redistributes the applied loads to mitigate high stresses and reduce tissue damage. By measuring local strain values and observing the distinct patterns they formed, it was possible to establish a connection between the healing phase of the tissue (determined by the time post-injury and the observed histological features) and the overall mechanical behaviour. Importantly, these parameters were measured from the surface of the tissue, using physiologically relevant strains without increasing the tissue's damage. Adaptations of these approaches for clinical use have the potential to aid in the identification of skin healing problems, such as excessive inflammation or lack of mechanical progression over time. An increase, decrease, or lack of change in the elasticity and viscoelasticity parameters, can be indicative of wound state, thus ultimately leading to improved diagnostic outcomes.

Scars

Wound healing occurs as a response to disruption of the epidermis and dermis. It is an intricate and well-orchestrated response with the goal to restore skin integrity and function. However, in hundreds of millions of patients, skin wound healing results in abnormal scarring, including keloid lesions or hypertrophic scarring. Although the underlying mechanisms of hypertrophic scars and keloid lesions are not well defined, evidence suggests that the changes in the extracellular matrix are perpetuated by ongoing inflammation in susceptible individuals, resulting in a fibrotic phenotype. The lesions then become established, with ongoing deposition of excess disordered collagen. Not only can abnormal scarring be debilitating and painful, it can also cause functional impairment and profound changes in appearance, thereby substantially affecting patients' lives. Despite the vast demand on patient health and the medical society, very little progress has been made in the care of patients with abnormal scarring. To improve the outcome of pathological scarring, standardized and innovative approaches are required.

Coherence function-encoded optical palpation

Optical palpation maps stress at the surface of biological tissue into 2D images. It relies on measuring surface deformation of a compliant layer, which to date has been performed with optical coherence tomography (OCT). OCT-based optical palpation holds promise for improved clinical diagnostics; however, the complexity and cost hinder broad adoption. In this Letter, we introduce coherence function-encoded optical palpation (CFE-OP) using a novel optical profilometry technique that exploits the envelope of the coherence function rather than its peak position, which is typically used to retrieve depth information. CFE-OP utilizes a Fabry-Perot laser diode (bandwidth, 2.2 nm) and a single photodiode in a Michelson interferometer to detect the position along the coherence envelope as a function of path length. This technique greatly reduces complexity and cost in comparison to the OCT-based approach. We perform CFE-OP on phantom and excised human breast tissue, demonstrating comparable mechanical contrast to OCT-based optical palpation and the capability to distinguish stiff tumor from soft benign tissue.