Infrared Thermography Shows That a Temperature Difference of 2.2°C (4°F) or Greater Between Corresponding Sites of Neuropathic Feet Does Not Always Lead to a Diabetic Foot Ulcer.

BACKGROUND: There is emerging interest in the application of foot temperature monitoring as means of diabetic foot ulcer (DFU) prevention. However, the variability in temperature readings of neuropathic feet remains unknown. The aim of this study was to analyze the long-term consistency of foot thermograms of diabetic feet at the risk of DFU. METHODS: A post-hoc analysis of thermal images of 15 participants who remained ulcer-free during a 12-month follow-up were unblinded at the end of the trial. Skin foot temperatures of 12 plantar, 15 dorsal, 3 lateral, and 3 medial regions of interests (ROIs) were derived on monthly thermograms. The temperature differences (∆Ts) of corresponding ROIs of both feet were calculated. RESULTS: Over the 12-month study period, out of the total 2026 plantar data points, 20.3% ROIs were rated as abnormal (absolute ∆T ≥ 2.2°C). There was a significant between-visit variability in the proportion of plantar ROIs with ∆T ≥ 2.2°C (range 7.6%-30.8%, chi-square test, P = .001). The proportion of patients presenting with hotspots (ROIs with ∆T ≥ 2.2°C), abnormal plantar foot temperature (mean ∆T of 12 plantar ROIs ≥ 2.2°C), and abnormal whole foot temperature (mean ∆T of 33 ROIs ≥ 2.2°C) varied between visits and showed no pattern (P > .05 for all comparisons). This variability was not related to the season of assessment. CONCLUSIONS: Despite the high rate of hotspots on monthly thermograms, all feet remained intact. This study underscores a significant between-visit inconsistency in thermal images of neuropathic feet which should be considered when planning DFU-prevention programs for self-testing and behavior modification.

Between visit variability of thermal imaging of feet in people attending podiatric clinics with diabetic neuropathy at high risk of developing foot ulcers.

OBJECTIVE: People with diabetic neuropathy who have previously ulcerated are at high risk of re-ulceration. They should regularly attend podiatry clinics for surveillance and routine protective podiatric treatment. It has been suggested that inflammation prior to skin breakdown shows up as a hotspot on a thermal image even in the absence of clinical signs. The aim of this study is to quantify inter-patient and intra-patient thermal variations presented by diabetic feet at high risk of ulceration. APPROACH: Whole foot and spot temperatures were recorded for 96 patients who attended two successive podiatry appointments without ulceration 28 [28, 31] days apart, median [interquartile range]. This was a part of a longer study into whether thermal imaging in clinic can reduce the rate of re-ulceration. MAIN RESULTS: The variation in spot temperature right/left differences for single patients between visits was comparable to the variation observed between patients (0.8 [0.3, 1.5] °C compared with 0.9 [0.4, 1.7] °C). Similarly, whole foot temperature variation for a single patient between visits was comparable to the variation observed between patients (0.6 [0.2, 1.1] °C compared with 0.8 [0.2, 1.3] °C). SIGNIFICANCE: Thresholds which depend on thermal differences from visit to visit are unlikely to have sufficient specificity to effectively target treatment designed to prevent the development of foot ulcers.

Thermal symmetry of healthy feet: a precursor to a thermal study of diabetic feet prior to skin breakdown.

Early identification of areas of inflammation may aid prevention of diabetic foot ulcers. A new bespoke thermal camera system has been developed to thermally image feet at risk. Hotspots (areas at least 2.2 °C hotter than the contralateral site) may indicate areas of inflammation prior to any apparent visual signs. This article describes the thermal pattern and symmetry of 103 healthy pairs of feet. 68% of participants were thermally symmetric at the 33 foot sites measured. 32% of participants had at least one hotspot, but hotspots overall only accounted for 5% of the measurements made. Refinements to the definition of hotspots are proposed when considering feet at risk of ulceration.

Quantification of skin lesions with a 3D stereovision camera system: validation and clinical applications.

BACKGROUND/PURPOSE: Three-dimensional (3D) imaging of the skin is a challenging technique. A new 3D digital camera system has been developed that enables 3D reconstruction of the skin and subsequently allows volumetric quantification. Herein we present validation data on calibrated phantoms and the clinical application of this technology. METHODS: Absolute and relative geometric 3D measurements were validated with a static imaging phantom manufactured by a metrology institution and a dynamic imaging phantom adjustable for different volume quantities, respectively. Consecutively, in a clinical study, 3D baseline and follow up images from 27 basal cell carcinomas under topical therapy were captured for volumetric analysis. RESULTS: Validation experiments have demonstrated an average accuracy for surface position of 55 µm and a precision of 8 µm, as well as excellent correlation (0.999) between injected and measured volumes. The geometric baseline analysis of 27 basal cell carcinomas exhibited a high correlation and agreement between 2D and 3D surface measurements. Under topical therapy, it was possible to gain statistically significant differences between verum- and vehicle-treated basal cell carcinomas when analyzing geometric measurements of 3D volume (P = 0.01) and 3D surface (P = 0.001). CONCLUSION: In our study we were able to demonstrate that this newly developed 3D camera system offers a precise objective dimensional representation of the skin. This technique is easily applicable and sensitive enough to measure small differences in area and volume before and after intervention.

3D imaging in forensic odontology.

This paper describes the investigation of a new 3D capture method for acquiring and subsequent forensic analysis of bite mark injuries on human skin. When documenting bite marks with standard 2D cameras errors in photographic technique can occur if best practice is not followed. Subsequent forensic analysis of the mark is problematic when a 3D structure is recorded into a 2D space. Although strict guidelines (BAFO) exist, these are time-consuming to follow and, due to their complexity, may produce errors. A 3D image capture and processing system might avoid the problems resulting from the 2D reduction process, simplifying the guidelines and reducing errors. Proposed Solution: a series of experiments are described in this paper to demonstrate that the potential of a 3D system might produce suitable results. The experiments tested precision and accuracy of the traditional 2D and 3D methods. A 3D image capture device minimises the amount of angular distortion, therefore such a system has the potential to create more robust forensic evidence for use in courts. A first set of experiments tested and demonstrated which method of forensic analysis creates the least amount of intra-operator error. A second set tested and demonstrated which method of image capture creates the least amount of inter-operator error and visual distortion. In a third set the effects of angular distortion on 2D and 3D methods of image capture were evaluated.

Adopting the DICOM standard for medical infrared images.

In recent years there has been a resurgence of interest in the application of infrared thermal imaging in medicine. Yet fairly little effort has been spent towards standardisation of the field and a common communication and exchange format for thermal images. Most other medical areas where digital imaging is employed have subscribed to DICOM (Digital Imaging and Communication in Medicine) as a common standard for storing and retrieving medical imagery. In this paper we investigate how the DICOM standard in its current form can be adopted to store and communicate medical infrared images.

Recording wound care effectiveness.

As more and more wound treatment regimes and wound care products become available, clinicians nowadays face the difficult task of choosing the right approach for individual patients amongst an ever expanding array of options. They find increasingly that a conventional subjective description of wound status and management approach in the patient's notes can no longer answer question such as how effective a treatment regime is or what the efficacy a selected wound care product may be at a given stage of the healing process. The only way to answer these questions and, ultimately, to improve patient care is the objective recording and documentation of the status of the wound and treatment related parameters. This paper outlines progress in a variety of technologies that are now beginning to become available in clinical practice, enabling practitioners to produce immediate, objective and quantifiable portraits of the healing process.