Relationship of skin temperature to sympathetic dysfunction in diabetic at-risk feet

The utility of skin surface temperature measurement in the prediction of diabetic foot ulceration

AIM

Temperature is a marker of inflammation. Research has shown that by measuring skin surface temperature in those with a history of diabetic foot ulceration (DFU), tissue damage can be identified early and reduce rates of subsequent DFU. This study considered whether measuring skin surface temperature using infra-red thermometry can identify early tissue damage and inform clinical practice in a general population with Diabetes Mellitus (DM).

METHOD

The data presented was taken from a prospective observational study of risk factors in patients with Diabetes. As part of this study, temperature measurements using the Flir E6 Infra-red camera were taken from 216 individuals attending outpatient diabetes clinics in a large urban teaching hospital in Ireland as part of a comprehensive diabetic foot assessment. Measurements were taken at foot sites associated with increased risk at baseline received repeat temperature measurement on 2 subsequent occasions in the following week. Any ulceration was subsequently recorded.

RESULTS

Discussion: Of the 216 participants, 4 % (n = 9) developed visual ulceration within 7 days. All of these had been identified at high risk at baseline assessment and had a history of foot disease. A temperature differential of ≥2.2 °C between sites of interest was recorded. Temperature ranges varied from 29.1 °C to 37.6 °C. High temperature was considered if over 35 °C. Of those who developed a diabetic foot ulceration within the 7 day follow up period, 78 % (n = 7) had a high temperature. The remaining 22 % (n = 2) who developed ulceration had a temperature reading in the normal range.

CONCLUSION

Elevated skin surface temperature was seen prior to the development of DFU in all cases in this study. Initial analysis suggests that neither the 35 °C threshold nor a 2.2 °C temperature difference is indicative of inevitable tissue damage in this population due to the high number of false positives seen.

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.

A Novel Perspective on Neuronal Control of Anatomical Patterning, Remodeling, and Maintenance

While the nervous system may be best known as the sensory communication center of an organism, recent research has revealed a myriad of multifaceted roles for both the CNS and PNS from early development to adult regeneration and remodeling. These systems work to orchestrate tissue pattern formation during embryonic development and continue shaping pattering through transitional periods such as metamorphosis and growth. During periods of injury or wounding, the nervous system has also been shown to influence remodeling and wound healing. The neuronal mechanisms responsible for these events are largely conserved across species, suggesting this evidence may be important in understanding and resolving many human defects and diseases. By unraveling these diverse roles, this paper highlights the necessity of broadening our perspective on the nervous system beyond its conventional functions. A comprehensive understanding of the complex interactions and contributions of the nervous system throughout development and adulthood has the potential to revolutionize therapeutic strategies and open new avenues for regenerative medicine and tissue engineering. This review highlights an important role for the nervous system during the patterning and maintenance of complex tissues and provides a potential avenue for advancing biomedical applications.

Wound pH and Surface Temperature as a Predictive Biomarker of Healing in Diabetic Foot Ulcers

Aim

To monitor wound pH and surface temperature as predictors of wound healing in diabetic foot ulcers (DFU).

Methods

Prospective, observational, time-bound study of 18 months, enrolling patients aged 18 to 60 years with uninfected DFU. The wound was assessed at baseline and after that, every week for 4 weeks according to the leg ulcer measurement tool (LUMT). Concurrently, wound surface pH and temperature were measured. The data were analyzed using descriptive statistics, and a P-value < .05 was considered statistically significant.

Results

Fifty-four patients with DFU were included in the study with a mean age of 55 years and a male to female ratio of 1.57. The wound showed progressive improvement, a maximum mean LUMT score of 48.89 (± 2.81) at the initial evaluation and decreased progressively to the mean of 19.80 at week 4 (± 3.43), both of which were statistically significant ( P-value < .001). Similarly, the median wound pH progressively reduced from 7.7 at baseline to 7.20 in the fourth week, and median wound temperature decreased from 90°F (32.22 °C) at baseline to 85°F (29.44 °C) in the fourth week, both of which were statistically significant ( P-value < .001).

Conclusion

Progressive and significant change in wound pH to acidic and drop in wound surface temperature, both corresponding to improvement in the status of DFU, maximum at 4 weeks, make them valuable predictors of wound healing. However, further, more extensive studies are required to establish a concrete relationship.

Feature Ranking by Variational Dropout for Classification Using Thermograms from Diabetic Foot Ulcers

Diabetes mellitus presents a high prevalence around the world. A common and long-term derived complication is diabetic foot ulcers (DFUs), which have a global prevalence of roughly 6.3%, and a lifetime incidence of up to 34%. Infrared thermograms, covering the entire plantar aspect of both feet, can be employed to monitor the risk of developing a foot ulcer, because diabetic patients exhibit an abnormal pattern that may indicate a foot disorder. In this study, the publicly available INAOE dataset composed of thermogram images of healthy and diabetic subjects was employed to extract relevant features aiming to establish a set of state-of-the-art features that efficiently classify DFU. This database was extended and balanced by fusing it with private local thermograms from healthy volunteers and generating synthetic data via synthetic minority oversampling technique (SMOTE). State-of-the-art features were extracted using two classical approaches, LASSO and random forest, as well as two variational deep learning (DL)-based ones: concrete and variational dropout. Then, the most relevant features were detected and ranked. Subsequently, the extracted features were employed to classify subjects at risk of developing an ulcer using as reference a support vector machine (SVM) classifier with a fixed hyperparameter configuration to evaluate the robustness of the selected features. The new set of features extracted considerably differed from those currently considered state-of-the-art but provided a fair performance. Among the implemented extraction approaches, the variational DL ones, particularly the concrete dropout, performed the best, reporting an F1 score of 90% using the aforementioned SVM classifier. In comparison with features previously considered as the state-of-the-art, approximately 15% better performance was achieved for classification.

Automatic Segmentation of Monofilament Testing Sites in Plantar Images for Diabetic Foot Management

Diabetic peripheral neuropathy is a major complication of diabetes mellitus, and it is the leading cause of foot ulceration and amputations. The Semmes–Weinstein monofilament examination (SWME) is a widely used, low-cost, evidence-based tool for predicting the prognosis of diabetic foot patients. The examination can be quick, but due to the high prevalence of the disease, many healthcare professionals can be assigned to this task several days per month. In an ongoing project, it is our objective to minimize the intervention of humans in the SWME by using an automated testing system relying on computer vision. In this paper we present the project’s first part, constituting a system for automatically identifying the SWME testing sites from digital images. For this, we have created a database of plantar images and developed a segmentation system, based on image processing and deep learning—both of which are novelties. From the 9 testing sites, the system was able to correctly identify most 8 in more than 80% of the images, and 3 of the testing sites were correctly identified in more than 97.8% of the images.

Infrared Thermography as a Method of Verification in Raynaud's Phenomenon

Raynaud's phenomenon (RP) is characterized by the episodic whitening of the fingers upon exposure to cold. A recently described thermographic algorithm was proposed as a diagnostic replacement of the currently applied finger systolic pressure (FSP) test. The aim of the study was to evaluate the performance of the thermographic algorithm when applied in patients suspected of having RP. Forty-three patients were examined using thermographic imaging after local cooling of the hands in water of 10 °C for 1 min. The thermographic algorithm was applied to predict the probability of RP. The performance of the algorithm was evaluated with different cut-off levels. A new algorithm was proposed based on patients from the target population. The performance of the tested algorithm was noninferior to the FSP test, when a cut-off level of 0.05 was applied, yielding a sensitivity and specificity of 69% and 58%, respectively. The accuracy was 66%. The FSP test had a sensitivity and specificity of 77% and 37%, respectively, and the accuracy was 59%. The thermographic method proved useful for detecting RP and was able to replace the FSP test as a diagnostic test. The alternative algorithm revealed that other thermographic variables were more predictive of the target population, but this should be verified in future patients.

Digital foot health technology and diabetic foot monitoring: A systematic review

BACKGROUND

In diabetic foot ulceration, a correlation between pressure and skin temperature is suspected. The aim of this systematic review is to provide a more rigorous analysis of existing literature related to the various technologies used to read and measure both in-shoe plantar pressures, and in-shoe skin temperatures simultaneously.

METHODS

A systematic review of the literature related to the topic was searched in database sources such as Medline OVID, Cochrane Library, PubMed, CONAHL, PROSPERO, and Elsevier. Outcome measures of interest included validity, reliability and responsiveness of in-shoe temperature and/or pressure mapping device used, and characteristics and quantity of sensors used, anatomical landmarks and statistical analysis used to interpret the data. Quality of evidence and risk of bias was evaluated using the QUADAS-2.

RESULTS

Nineteen studies were identified and included in this review. The majority of studies used a small sample size (mean n = 17) and recruited healthy participants. All studies have shown excellent validity but only a few tested for the reliability of the device. None of the studies tested for responsiveness of the device. Quality assessment results scored high risk in view of 'patient selection', 'use of reference standard' and 'applicability', and low risk in view of 'use if index test' and 'flow and timing'.

CONCLUSIONS

The data outlined in this review confirms that further improvement, reliability testing and clinical validation of the developed systems is required despite the results of excellent performance in detecting changes of in-shoe skin temperature and pressure.

A smart wearable device for monitoring and self-management of diabetic foot: A proof of concept study

BACKGROUND AND OBJECTIVE

Diabetic foot is one of the important complications of diabetes, which is occurred due to the destructive parameters in different anatomical sites of feet. Management and monitoring of these parameters are very important to decrease or prevent foot ulcers. We aimed to develop a smart wearable device to monitor these parameters to prevent diabetic foot.

METHODS

Following literature review and expert panel discussions, we considered pressure, temperature and humidity to develop the system. During these sessions, we also developed the system architecture and determined the required technologies. We also developed a mobile application. Finally, all sensors were evaluated for accurate monitoring of pressure, temperature and humidity. A standard protocol was used to evaluate each of these sensors. To this end, five people (four with diabetes and one healthy person) participated. They did a series of movements including walking, sitting, and standing. We considered the pressure measured by Pedar system as the gold standard. Furthermore, we changed the environment temperature and humidity during several experiments and considered the environment temperature and humidity as gold standard. We compared the measured values by sensors with these gold standards.

RESULTS

The evaluation indicated the accurate performance of pressure, humidity and temperature sensors. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the system to provide alarms based on the pressure measured using Pedar were 100, 50, 92.5, 91.8, and 100 %, respectively. The performance of temperature sensors in smart shoes was confirmed by slight differences compared to thermometers. Relatively equal values of humidity measured by two sensors on the left and right feet and the increased difference with the environment humidity showed the exact humidity measured using these sensors.

CONCLUSION

This smart shoes monitors pressure, humidity, and temperature of patients' feet and sends this data to their smart phone by the Bluetooth module. Furthermore, it controls these parameters; as each of these parameters exceeds the defined threshold, alerts are given to patients for self-management.

DIEP flap breast reconstructions: thermographic assistance as a possibility for perforator mapping and improvement of DIEP flap quality

In the modern world, one-third or more of breast cancer patients still undergo uni- or bilateral mastectomy. Breast cancer patients, in general, have a good prognosis and long-term survival. Therefore, the treatment must not only focus on survival but also on the quality of life. Breast reconstruction with an autologous free deep inferior epigastric artery perforator (DIEP) flap is one of the preferred options after mastectomy. A challenging step in this procedure is the selection of a suitable perforator that provides sufficient blood supply for the flap to prevent necrosis after anastomosis. In this pilot study, the possibilities for dynamic infrared thermography (DIRT) are investigated to select the best suitable perforator. The measurements are done with external cooling in the preoperative stage to accurately predict the location of the dominant perforators. During the surgery, in the peroperative stage, measurements are done for mapping the influence of a specific perforator on the perfused areas of the abdominal flap. Perforators are sequentially closed and opened again to map the influence of that perforator on the vascularization of the flap, visualized with the help of the thermographic camera. The acquired steady-state thermal images could help decide which parts of the abdominal flap to use for the reconstruction so that the chance of (partial) necrosis is reduced. In the postoperative stage, DIRT could visualize the arterial and or venous thrombosis before they become clinically obvious as (partial) necrosis. At present DIRT seems to be a valuable investigation for the pre-, per-, and postoperative phases of DIEP-flap reconstructions. Large, high-quality clinical studies are needed to determine its definitive role.

Thermal Asymmetries and Mean Foot Temperature

Foot problems can cause pain and discomfort, limiting the activities of many individuals. Infrared thermography may be useful for early detection of abnormal temperatures using various ways of calculating the mean foot temperature (MFT) to analyze asymmetries and differences between different groups. The aim of this study was to compare two protocols for calculating the MFT, identifying the magnitude of asymmetries in several regions and their correlations with the forehead temperature and brain temperature tunnel(BTT).Nineteen healthy volunteers of both genders aged between 18 and 55 years participated in the study.Data collection included anamnesis, body mass measurement, stature, glycaemia, body core temperature and acquisition of thermal images of the feet and face. The Wilcoxon test revealed that the mean foot temperature calculated using hallux, 2^nd, 3^rd, 4^th and 5^th toes, 1^st, 3^rd and 5^th metatarsal heads and heel, was lower than that calculated without the four lesser toes (Z = -2.636, p = 0.008).However, the asymmetry between the two feet was the same in both cases (medianof 0.4 °C). The correlations of the MFT with the forehead temperature and BTT were positive and significant for the two forms of calculation, and the correlation was stronger when all toes were used to calculate the mean (forehead: ρ = 0.654, p = 0.002, BTT: ρ = 0.617, p = 0.005). The study showed the relevance of the toes in the analysis of the MFT, and it may be important to evaluate asymmetries in the toes to detect abnormal thermal patterns. This finding suggests that it is preferable to use MFT calculated with all toes.

Prediction of Diabetic Foot Ulceration: The Value of Using Microclimate Sensor Arrays

BACKGROUND

Accurately predicting the risk of diabetic foot ulceration (DFU) could dramatically reduce the enormous burden of chronic wound management and amputation. Yet, the current prognostic models are unable to precisely predict DFU events. Typically, efforts have focused on individual factors like temperature, pressure, or shear rather than the overall foot microclimate.

METHODS

A systematic review was conducted by searching PubMed reports with no restrictions on start date covering the literature published until February 20, 2019 using relevant keywords, including temperature, pressure, shear, and relative humidity. We review the use of these variables as predictors of DFU, highlighting gaps in our current understanding and suggesting which specific features should be combined to develop a real-time microclimate prognostic model.

RESULTS

The current prognostic models rely either solely on contralateral temperature, pressure, or shear measurement; these parameters, however, rarely reach 50% specificity in relation to DFU. There is also considerable variation in methodological investigation, anatomical sensor configuration, and resting time prior to temperature measurements (5-20 minutes). Few studies have considered relative humidity and mean skin resistance.

CONCLUSION

Very limited evidence supports the use of single clinical parameters in predicting the risk of DFU. We suggest that the microclimate as a whole should be considered to predict DFU more effectively and suggest nine specific features which appear to be implicated for further investigation. Technology supports real-time in-shoe data collection and wireless transmission, providing a potentially rich source of data to better predict the risk of DFU.

Temperature as a Causative Factor in Diabetic Foot Ulcers: A Call to Revisit Ulceration Pathomechanics

BACKGROUND

Diabetic foot ulcers (DFUs) are a major burden to patients and to the health-care systems of many countries. To prevent or treat ulcers more effectively, predictive biomarkers are needed. We examined temperature as a biomarker and as a causative factor in ulcer development.

METHODS

Thirty-seven individuals with diabetes were enrolled in this observational case-control study: nine with diabetic neuropathy and ulcer history (DFU), 14 with diabetic neuropathy (DN), and 14 nonneuropathic control participants (DC). Resting barefoot plantar temperatures were recorded using an infrared thermal camera. Mean temperatures were determined in four anatomical regions-hallux and medial, central, and lateral forefoot-and separate linear models with specified contrasts among the DFU, DN, and DC groups were set to reveal mean differences for each foot region while controlling for group characteristics.

RESULTS

The mean temperature reading in each foot region was higher than 30.0°C in the DFU and DN groups and lower than 30.0°C in the DC group. Mean differences were greatest between the DFU and DC groups, ranging from 3.2°C in the medial forefoot to 4.9°C in the hallux.

CONCLUSIONS

Increased plantar temperatures in individuals with a history of ulcers may include acute temperature increases from plantar stresses, chronic inflammation from prolonged stresses, and impairment in temperature regulation from autonomic neuropathy. Diabetic foot temperatures, particularly in patients with previous ulcers, may easily reach hazard thresholds indicated by previous pressure ulcer studies. The results necessitate further exploration of temperature in the diabetic foot and how it may contribute to ulceration.

Relationship between skin temperature and soft tissue hardness in diabetic patients: an exploratory study

OBJECTIVE

The role of skin temperature and soft tissue hardness in the development of plantar ulcers is still in debate. However, the relationship between skin temperature and soft tissue hardness has not been explored. This study intends to analyse an eventual association between skin temperature and soft tissue hardness in the foot of diabetic patients Approach: Twenty diabetic patients enrolled for this study. The analysis was done at the foot level, therefore, skin temperature and soft tissue hardness data of the plantar surface of 40 feet were obtained in eight regions of the foot, two in the heel, two in the midfoot, three in the forefoot and one in the hallux. Information regarding glycaemic control (HbA1c levels) was retrieved from the clinical records of the patients.

MAIN RESULTS

After averaging skin temperature and soft tissue hardness in the calcaneum (medial and lateral), in the midfoot (medial and lateral) and in the metatarsal head (1st, 2nd-3rd and 4th-5th), a negative, moderate and significant association was found between skin temperature and soft tissue hardness in the metatarsal head (rho  =  -0.553; p   <  0.001), a positive, low and significant association was found in the midfoot (rho  =  0.333; p   =  0.036), but no association was found in the heel. The multiple linear regression models with skin temperature as dependent variable and soft tissue hardness as predictor were statistically significant in the metatarsal heads and midfoot, and explained 28.8% (R ²  =  0.288, F _(1,38)  =  15.37, p   <  0.001) and 11.9% (R ²  =  0.119, F _(1,38)  =  5.151, p   =  0.029) of the variance in skin temperature, respectively.

SIGNIFICANCE

Skin temperature is negatively associated with soft tissue hardness in the metatarsal head region and positively associated with soft tissue hardness in the midfoot. These findings imply that soft tissue hardness should be considered in the assessment of diabetic foot patients and that this variable should be controlled in studies assessing the determinants of foot skin temperature.

Relationship between skin temperature monitoring with Smart Socks and plantar pressure distribution: a pilot study

OBJECTIVE

Increased skin temperature at the plantar aspect of the foot can predict foot ulceration. However its relation to plantar pressure overload is unknown. The aim of this study was to assess the ability of 'smart socks', monitoring plantar temperature under real-life conditions, to predict plantar pressure distribution.

METHOD

The 'smart socks' have seven thermal sensors woven into the fabric of the sock to measure the temperature beneath the foot in real-life conditions. The upper part of the sock is connected to a central unit through which changes in the sensor resistance is converted into temperature changes. Participants were instructed to wear the socks for three continuous hours. Plantar pressure was measured by the MatScan plantar-pressure measurement system (Tekscan Inc., US).

RESULTS

The study included 25 healthy volunteers (11 males, 14 females, mean age was 41.1 years (standard deviation (SD): 17.6) years, a mean body mass index of 29.4 kg/m² (SD: 6.95). Temperature changes at sensor (S) five significantly correlated with metatarsal (M) 2 pressure time integral (PTI) (r=0.519, p=0.008), M3 PTI (r=0.435, p=0.03), M4 PTI (r=0.452, p=0.023). Changes at S5 also significantly correlated with peak pressure at M2 (r=0.66, p=0.000), M3 (r=0.52, p=0.01), and M4 (r=0.60, p=0.002). Temperature changes at S6 were significantly correlated with changes at S1, S2, S3, S4, S5, and S7.

CONCLUSION

Temperature changes at the plantar aspect of the foot measured by the smart socks are correlated with plantar pressure distribution. Furthermore, two sensors at positions S5 and S6 were sufficient to predict plantar pressure changes.

Lumbar sympathectomy regulates vascular cell turnover in rat hindfoot plantar skin

BACKGROUND

Sympathetic denervation and impaired angiogenesis cause skin diseases. However, the relationship between the sympathetic nervous system and vascular cell turnover in normal skin remains unclear.

OBJECTIVE

To determine the effects of sympathetic denervation on vascular cell turnover in normal skin.

METHODS

Rats underwent bilateral L2-4 sympathetic trunk resection (sympathectomy group) or sham operation (control). Hindfoot plantar skin was analyzed 2 weeks and 3 months postoperatively.

RESULTS

Mural cell marker (α-smooth muscle actin; p < 0.001, and desmin; p = 0.047) expression decreased 2 weeks after sympathectomy, but recovered 3 months after sympathectomy (p > 0.05). CD31 levels were lower in the experimental group than in the control group at 2 weeks (p = 0.009), but not at 3 months. Von Willebrand factor, vascular endothelial growth factor, and angiopoietin-2 expression were not significantly different between the groups (p > 0.05). Angiopoietin-1 expression levels were higher in the experimental group than in the control group at 2 weeks (p = 0.035), but not at 3 months.

CONCLUSIONS

Lumbar sympathectomy regulates vascular cell turnover in rat hindfoot plantar skin by inhibiting mural cell proliferation and increasing angiopoietin-1 expression. Sympathetic nerves therefore play an important role in plantar skin vascular cell turnover.

Establishing Differences in Thermographic Patterns between the Various Complications in Diabetic Foot Disease

AIM

To evaluate the potential of thermography as an assessment tool for the detection of foot complications by understanding the variations in temperature that occur in type 2 diabetes mellitus (DM).

METHODS

Participants were categorized according to a medical examination, ankle brachial index, doppler waveform analysis, and 10-gram monofilament testing into five groups: healthy adult, DM with no complications, DM with peripheral neuropathy, DM with neuroischaemia, and DM with peripheral arterial disease (PAD) groups. Thermographic imaging of the toes and forefeet was performed.

RESULTS

43 neuroischaemic feet, 41 neuropathic feet, 58 PAD feet, 21 DM feet without complications, and 126 healthy feet were analyzed. The temperatures of the feet and toes were significantly higher in the complications group when compared to the healthy adult and DM healthy groups. The higher the temperatures of the foot in DM, the higher the probability that it is affected by neuropathy, neuroischaemia, or PAD.

CONCLUSIONS

Significant differences in mean temperatures exist between participants who were healthy and those with DM with no known complications when compared to participants with neuroischaemia, neuropathy, or PAD. As foot temperature rises, so does the probability of the presence of complications of neuropathy, neuroischaemia, or peripheral arterial disease.

Computer aided diagnosis of diabetic foot using infrared thermography: A review

Diabetes mellitus (DM) is a chronic metabolic disorder that requires regular medical care to prevent severe complications. The elevated blood glucose level affects the eyes, blood vessels, nerves, heart, and kidneys after the onset. The affected blood vessels (usually due to atherosclerosis) may lead to insufficient blood circulation particularly in the lower extremities and nerve damage (neuropathy), which can result in serious foot complications. Hence, an early detection and treatment can prevent foot complications such as ulcerations and amputations. Clinicians often assess the diabetic foot for sensory deficits with clinical tools, and the resulting foot severity is often manually evaluated. The infrared thermography is a fast, nonintrusive and non-contact method which allows the visualization of foot plantar temperature distribution. Several studies have proposed infrared thermography-based computer aided diagnosis (CAD) methods for diabetic foot. Among them, the asymmetric temperature analysis method is more superior, as it is easy to implement, and yielded satisfactory results in most of the studies. In this paper, the diabetic foot, its pathophysiology, conventional assessments methods, infrared thermography and the different infrared thermography-based CAD analysis methods are reviewed.

New horizons in the understanding of the causes and management of diabetic foot disease: report from the 2017 Diabetes UK Annual Professional Conference Symposium

Diabetes-related foot disease remains a common problem. For wounds, classic teaching recommends the treatment of any infection, offloading the wound and ensuring a good blood supply, as well as ensuring that the other modifiable risk factors are addressed and optimized. There remain, however, several questions about these and other aspects of the care of diabetes-related foot disease. Some of these questions are addressed in the present report; in particular, the impact of newer technologies in the identification of any organisms present in a wound, as well as the use of novel approaches to treat infections. The use of new remote sensing technology to identify people at risk of developing foot ulceration is also considered, in an attempt to allow early intervention and prevention of foot ulcers. The psychological impact of foot disease is often overlooked, but with an increasing number of publications on the subject, the cause-and-effect role that psychology plays in foot disease, such as ulcers and Charcot neuroarthropathy, is considered. Finally, because of heterogeneity in diabetic foot studies, comparing results is difficult. A recently published document focusing on ensuring a standardized way of reporting foot disease trials is discussed.

Delivery of Flightless I Neutralizing Antibody from Porous Silicon Nanoparticles Improves Wound Healing in Diabetic Mice

Flightless I (Flii) is elevated in human chronic wounds and is a negative regulator of wound repair. Decreasing its activity improves healing responses. Flii neutralizing antibodies (FnAbs) decrease Flii activity in vivo and hold significant promise as healing agents. However, to avoid the need for repeated application in a clinical setting and to protect the therapeutic antibody from the hostile environment of the wound, suitable delivery vehicles are required. In this study, the use of porous silicon nanoparticles (pSi NPs) is demonstrated for the controlled release of FnAb to diabetic wounds. We achieve FnAb loading regimens exceeding 250 µg antibody per mg of vehicle. FnAb-loaded pSi NPs increase keratinocyte proliferation and enhance migration in scratch wound assays. Release studies confirm the functionality of the FnAb in terms of Flii binding. Using a streptozotocin-induced model of diabetic wound healing, a significant improvement in healing is observed for mice treated with FnAb-loaded pSi NPs compared to controls, including FnAb alone. FnAb-loaded pSi NPs treated with proteases show intact and functional antibody for up to 7 d post-treatment, suggesting protection of the antibodies from proteolytic degradation in wound fluid. pSi NPs may therefore enable new therapeutic approaches for the treatment of diabetic ulcers.

Characterizing human skin blood flow regulation in response to different local skin temperature perturbations

Small nerve fibers regulate local skin blood flow in response to local thermal perturbations. Small nerve fiber function is difficult to assess with classical neurophysiological tests. In this study, a vasomotor response model in combination with a heating protocol was developed to quantitatively characterize the control mechanism of small nerve fibers in regulating skin blood flow in response to local thermal perturbation. The skin of healthy subjects' hand dorsum (n=8) was heated to 42°C with an infrared lamp, and then naturally cooled down. The distance between the lamp and the hand was set to three different levels in order to change the irradiation intensity on the skin and implement three different skin temperature rise rates (0.03°C/s, 0.02°C/s and 0.01°C/s). A laser Doppler imager (LDI) and a thermographic video camera recorded the temporal profile of the skin blood flow and the skin temperature, respectively. The relationship between the skin blood flow and the skin temperature was characterized by a vasomotor response model. The model fitted the skin blood flow response well with a variance accounted for (VAF) between 78% and 99%. The model parameters suggested a similar mechanism for the skin blood flow regulation with the thermal perturbations at 0.03°C/s and 0.02°C/s. But there was an accelerated skin vasoconstriction after a slow heating (0.01°C/s) (p-value<0.05). An attenuation of the skin vasodilation was also observed in four out of the seven subjects during the slow heating (0.01°C/s). Our method provides a promising way to quantitatively assess the function of small nerve fibers non-invasively and non-contact.

Sympathetic Dysfunction in Patients With Chronic Low Back Pain and Failed Back Surgery Syndrome

BACKGROUND

Chronic low back pain (CLBP) is defined as pain that persists longer than 12 weeks and is often attributed to degenerative or traumatic conditions of the spine. Failed back surgery syndrome is a condition in which chronic pain persists after spinal surgery. Electrodiagnostic studies can be used to confirm the diagnosis of lumbosacral radiculopathy, but other diagnostic methods are often needed to assess sympathetic nervous system dysfunction.

OBJECTIVES

The aim of this study was to investigate the affection of sympathetic skin response (SSR) in cases of chronic low back pain (LBP) and failed back surgery syndrome (FBSS) and to assess the association of SSR abnormalities with perceived functional disability and pain among these patients.

METHODOLOGY

Twenty patients with CLBP and 10 patients with failed FBSS who fulfilled the inclusion criteria were recruited to the present study. All cases had back, leg, or back and leg pain of at least 3-month duration or following spinal surgery. The control group consists of 10 healthy participants matched in age and sex. Electrophysiologic nerve conduction studies and SSR recording were applied on the symptomatic and normal side in study cases and on both sides in the control group. Pain intensity was analyzed by the visual analogue scale (VAS) and perceived functional disability was assessed with the Oswestry disability index (ODI).

CONCLUSIONS

It was concluded that the sympathetic nervous system is affected in CLBP and FBSS patients with abnormalities in SSR and that the dysfunction of sympathetic nervous system may contribute to the intensity and chronicity of pain in these groups of patients. Moreover, a strong association was found between SSR and functional disabilities in these patients.

Portable System for Monitoring the Microclimate in the Footwear-Foot Interface

A new, continuously-monitoring portable device that monitors the diabetic foot has shown to help in reduction of diabetic foot complications. Persons affected by diabetic foot have shown to be particularly sensitive in the plantar surface; this sensitivity coupled with certain ambient conditions may cause dry skin. This dry skin leads to the formation of fissures that may eventually result in a foot ulceration and subsequent hospitalization. This new device monitors the micro-climate temperature and humidity areas between the insole and sole of the footwear. The monitoring system consists of an array of ten sensors that take readings of relative humidity within the range of 100% ± 2% and temperature within the range of −40 °C to 123.8 ± 0.3 °C. Continuous data is collected using embedded C software and the recorded data is processed in Matlab. This allows for the display of data; the implementation of the iterative Gauss-Newton algorithm method was used to display an exponential response curve. Therefore, the aim of our system is to obtain feedback data and provide the critical information to various footwear manufacturers. The footwear manufactures will utilize this critical information to design and manufacture diabetic footwear that reduce the risk of ulcers in diabetic feet.

Dermatological and musculoskeletal assessment of diabetic foot: A narrative review

AIMS

Diabetic Foot Syndrome (DFS) is the most costly and devastating complication of diabetes mellitus (DM), which early effective assessment can reduce the severity of complications including ulceration and amputations. This study aimed to review dermatological and musculoskeletal assessment of diabetic foot.

MATERIALS AND METHODS

In this review article, we searched for articles published between March 1, 1980 and July 28, 2015 in PubMed, Science Direct, Embase, Web of Science, and Scopus, for both English and non-English language articles with the following keywords: "Diabetic foot syndrome", "Ulceration", "Amputation", "Foot assessment", "Skin disorders" and "Musculoskeletal deformities".

RESULTS

In dermatological dimension, most studies focused on elucidated changes in skin temperature, color, hardiness and turgor as well as common skin disorders such as Diabetic Dermopathy (DD), Necrobiosis Lipoidica Diabeticorum (NLD) and Diabetic Bullae (DB), which are common in diabetic patients and have high potential for leading to limb-threatening problems such as ulceration and infection. In musculoskeletal dimension, most studies focused on range of motion and muscle strength, gait patterns and as well as foot deformities especially Charcot osteoarthropathy (COA), which is the most destructive musculoskeletal complication of diabetes.

CONCLUSION

DFS as a common condition in DM patients lead to ulceration and lower limb amputation frequently unless a prompt and comprehensive assessment was taken. So that dermatological and musculoskeletal assessments are usually neglected in primary health care, these assessments should be done frequently to reduce the high risk of serious complications.

Reproducibility of axon reflex-related vasodilation assessed by dynamic thermal imaging in healthy subjects

INTRODUCTION

Small nerve fiber dysfunction is an early feature of diabetic neuropathy. There is a strong clinical need for a non-invasive method to assess small nerve fiber function. Small nerve fibers mediate axon reflex-related vasodilation and play an important role in thermoregulation. Assessing the reflex vasodilation after local heating might elucidate some aspects of small fiber functioning. In this study, we determined the reproducibility of the reflex vasodilation after short local heating in healthy subjects, assessed with thermal imaging and laser Doppler imaging.

METHODS

Healthy subjects underwent six heating rounds in one session (protocol I, N=10) or spread over two visits (protocol II, N=20). Reflex vasodilation was elicited by heating the skin to 42°C with an infrared lamp. Skin temperature and skin blood flow were recorded during heating and recovery with a thermal imaging camera and a laser Doppler imager. Skin temperature curves were fitted with a mathematical model to describe the heating and recovery phase with time constant tau (tauHeat and tauCool1).

RESULTS

The reproducibility of tau within a session was moderate to excellent (intra-class correlation coefficient 0.42-0.86) and good (0.71-0.72) between different sessions. Within one session the differences in tauHeat were small (bias±SD -1.3±18.9s); the bias between two visits was -1.2±12.2s. For tauCool1 the differences were also small, 1.4±6.6s within a session and between visits -1.4±11.6s.

CONCLUSIONS

The heat induced axon reflex-related vasodilation, assessed with thermal imaging and laser Doppler imaging, was reproducible both within a session and between different sessions. Tau describes the temporal profile in one parameter and represents the effects of all changes including blood flow and as such, is an indicator of the vasodilator function. TauHeat and tauCool1 can accurately describe the dynamics of the axon reflex-related vasodilator response in the heating and recovery phase respectively.

Edema, Hyperpigmentation, Induration: 3 Skin Signs Heralding Danger in Patients on Maintenance Hemodialysis

Skin changes are common in patients on dialysis. This study focused on putative associations of specific skin findings with comorbidities and mortality.We performed a retrospective analysis of data from 508 patients on maintenance hemodialysis therapy in 7 centers in the German State of North Rhine Westphalia. Data had been collected by interview, from patient files, and from targeted physical examination in an earlier prospective study screening hemodialysis patients for the presence of nephrogenic systemic fibrosis. While on dialysis, patients' extremities had been examined for any of the following: edematous skin at the lower extremities, hyperpigmentation, induration, and xerosis cutis. Our present data analyses focused on associated mortality and comorbidities.Five hundred eight patients (median age 71 years, range 20.0-95.9; n = 292 men) had agreed to participate in the initial study: 48% (n = 243) were diabetics and 46% (n = 232) had been diagnosed with coronary heart disease. On examination, 86% of patients (n = 439) presented with at least 1 of the prespecified skin changes. Skin edema (n = 89; 18%), hyperpigmentation (n = 74; 15%), and induration (n = 9; 2%) were independently associated with increased mortality over 24 months (P < 0.002, P < 0.030, and P < 0.020, respectively).In our study, prespecified skin changes indicated an increased mortality risk in patients on chronic hemodialysis. Routinely assessing the skin of dialysis patients represents a simple, reliable, and cost effective means of identifying those at greatest risk.

Detection of diabetic foot hyperthermia by infrared imaging

In diabetic foot, the occurrence of an ulcer is often associated with hyperthermia. Hyperthermia is defined as a temperature greater than 2.2°C in a given region of one of the foot compared to the temperature of the same region of the contralateral foot. Unfortunately, hyperthermia is not yet assessed in current diabetic foot therapy. In this paper, we propose an easy way to detect a possible hyperthermia by using an infrared camera. A specific acquisition protocol of the thermal images is proposed. A dedicated image analysis is developed: it is composed of a contour detection of the 2 feet using the Chan and Vese active contour method associated to the ICP rigid registration technique. Among 85 type II diabetes persons recruited in the Dos de Mayo hospital in Lima, Peru, 9 individuals show significant hyperthermia. It is expected that the new possibility of detecting hyperthermia in hospitals or in diabetic health centers which is now available, thanks to the proposed method, will help in reducing foot ulcer occurrence for diabetic persons.

A review of thermal methods and technologies for diabetic foot assessment

Temperature analysis has been considered as a complementary method in medical evaluation and diagnosis. Several studies demonstrated that monitoring the temperature variations of the feet of diabetic patients can be helpful in the early identification of diabetic foot manifestations, and also in changing behaviors, which may contribute to reducing its incidence. In this review, several and most used techniques for assessing the temperature of the feet are presented, along with original published work on specific applications in diabetic foot complications. A review of solutions and equipment that operate according to the temperature assessment techniques is also presented. Finally, a comparison between the various technologies is presented, and the authors share their perspective on what will be the state of affairs in 5 years.

Automatic detection of diabetic foot complications with infrared thermography by asymmetric analysis

Early identification of diabetic foot complications and their precursors is essential in preventing their devastating consequences, such as foot infection and amputation. Frequent, automatic risk assessment by an intelligent telemedicine system might be feasible and cost effective. Infrared thermography is a promising modality for such a system. The temperature differences between corresponding areas on contralateral feet are the clinically significant parameters. This asymmetric analysis is hindered by (1) foot segmentation errors, especially when the foot temperature and the ambient temperature are comparable, and by (2) different shapes and sizes between contralateral feet due to deformities or minor amputations. To circumvent the first problem, we used a color image and a thermal image acquired synchronously. Foot regions, detected in the color image, were rigidly registered to the thermal image. This resulted in 97.8% ± 1.1% sensitivity and 98.4% ± 0.5% specificity over 76 high-risk diabetic patients with manual annotation as a reference. Nonrigid landmark-based registration with B-splines solved the second problem. Corresponding points in the two feet could be found regardless of the shapes and sizes of the feet. With that, the temperature difference of the left and right feet could be obtained.

Sensitivity and specificity of a new test for thermographic evaluation of the foot in the diagnosis of diabetic peripheral polyneuropathy

OBJECTIVE

This work determined the sensitivity, specificity, and predictive values of a test evaluating the thermal perception threshold to cold and heat and established a thermal interval with the participant's basal temperature in order to detect diabetic peripheral neuropathy in 172 people with diabetes, 86 with and 86 without diabetic neuropathy.

DESIGN

This was a cross-sectional, diagnosis accuracy study.

SETTING

This research was performed from January 2010 to February 2012 in Seville, Spain, and Córdoba, Spain.

PARTICIPANTS

One hundred seventy-two people with diabetes, 86 with and 86 without diabetic neuropathy, were recruited to participate in the study.

MAIN OUTCOME MEASURES

The thermal sensitivity was examined in the participants' feet with an instrument designed to assess thermal discrimination and sensitivity based on the Peltier principle. The skin temperature was recorded, and it was performed the following tests: (1) determining the thermal discrimination threshold, used to identify the lowest noticeable temperature difference, and (2) examining the thermal sensitivity, used to determine the absolute thermal threshold. The receiver operating characteristic curve technique was used to calculate the sensitivity, specificity, and predictive values.

MAIN RESULTS

The area under the curve that showed the best sensitivities and specificities bilaterally was for the warm temperatures under the first and fifth metatarsal heads. In these zones, the temperature difference needed to predict whether a patient was neuropathic was 2°C. Sensitivities were greater than 75%, and the positive predictive values in all cases exceeded 60%.

CONCLUSIONS

This technique enabled the authors to quantify the degrees of colder or warmer temperature differences that participants with diabetes (with and without neuropathy) needed to be able to detect a difference, with acceptable sensitivity, specificity, and predictive values.

Application of infrared thermography in computer aided diagnosis

The invention of thermography, in the 1950s, posed a formidable problem to the research community: What is the relationship between disease and heat radiation captured with Infrared (IR) cameras? The research community responded with a continuous effort to find this crucial relationship. This effort was aided by advances in processing techniques, improved sensitivity and spatial resolution of thermal sensors. However, despite this progress fundamental issues with this imaging modality still remain. The main problem is that the link between disease and heat radiation is complex and in many cases even non-linear. Furthermore, the change in heat radiation as well as the change in radiation pattern, which indicate disease, is minute. On a technical level, this poses high requirements on image capturing and processing. On a more abstract level, these problems lead to inter-observer variability and on an even more abstract level they lead to a lack of trust in this imaging modality. In this review, we adopt the position that these problems can only be solved through a strict application of scientific principles and objective performance assessment. Computing machinery is inherently objective; this helps us to apply scientific principles in a transparent way and to assess the performance results. As a consequence, we aim to promote thermography based Computer-Aided Diagnosis (CAD) systems. Another benefit of CAD systems comes from the fact that the diagnostic accuracy is linked to the capability of the computing machinery and, in general, computers become ever more potent. We predict that a pervasive application of computers and networking technology in medicine will help us to overcome the shortcomings of any single imaging modality and this will pave the way for integrated health care systems which maximize the quality of patient care.

Quantitative estimation of temperature variations in plantar angiosomes: a study case for diabetic foot

Thermography is a useful tool since it provides information that may help in the diagnostic of several diseases in a noninvasive and fast way. Particularly, thermography has been applied in the study of the diabetic foot. However, most of these studies report only qualitative information making it difficult to measure significant parameters such as temperature variations. These variations are important in the analysis of the diabetic foot since they could bring knowledge, for instance, regarding ulceration risks. The early detection of ulceration risks is considered an important research topic in the medicine field, as its objective is to avoid major complications that might lead to a limb amputation. The absence of symptoms in the early phase of the ulceration is conceived as the main disadvantage to provide an opportune diagnostic in subjects with neuropathy. Since the relation between temperature and ulceration risks is well established in the literature, a methodology that obtains quantitative temperature differences in the plantar area of the diabetic foot to detect ulceration risks is proposed in this work. Such methodology is based on the angiosome concept and image processing.

Morphological pattern classification system for plantar thermography of patients with diabetes

BACKGROUND

A plantar temperature distribution can be obtained by thermography; however, the advantage has not been effectively utilized in the past. We previously proposed a classification method based on the angiosome concept, but the method was insufficient because it was too subjective and complicated for clinicians. In this study, we propose a new classification system of plantar forepart thermographic patterns using an image segmentation technique.

METHODS

A cross-sectional observational study was conducted including 32 healthy volunteers and 129 patients with diabetes mellitus (DM). Individual thermographic variations and trends were evaluated. A comparison was conducted between the patterns obtained by our previous angiosome-based research and the patterns found by the new classification system.

RESULTS

The system objectively found wider variations of the plantar forepart thermographic patterns in the patients with DM compared with those in the control subjects. In patients with DM, the system showed that the whole-high pattern was most frequent (46%), followed by the butterfly pattern (12%). In the control group, the butterfly pattern was most frequent (44%), followed by the whole-high pattern (19%). Both ankle and toe brachial indices were higher in feet with high temperature area in the inner side of the plantar.

CONCLUSIONS

Thermographic patterns found by the new computer-based system were similar to those obtained in our previous subjective work. The classification system found forefoot-low pattern and tiptoe-low pattern objectively. The system based on infrared thermography will be a screening tool to assess circulatory status in daily foot care of patients with DM.

Medical applications of infrared thermography: A review

Abnormal body temperature is a natural indicator of illness. Infrared thermography (IRT) is a fast, passive, non-contact and non-invasive alternative to conventional clinical thermometers for monitoring body temperature. Besides, IRT can also map body surface temperature remotely. Last five decades witnessed a steady increase in the utility of thermal imaging cameras to obtain correlations between the thermal physiology and skin temperature. IRT has been successfully used in diagnosis of breast cancer, diabetes neuropathy and peripheral vascular disorders. It has also been used to detect problems associated with gynecology, kidney transplantation, dermatology, heart, neonatal physiology, fever screening and brain imaging. With the advent of modern infrared cameras, data acquisition and processing techniques, it is now possible to have real time high resolution thermographic images, which is likely to surge further research in this field. The present efforts are focused on automatic analysis of temperature distribution of regions of interest and their statistical analysis for detection of abnormalities. This critical review focuses on advances in the area of medical IRT. The basics of IRT, essential theoretical background, the procedures adopted for various measurements and applications of IRT in various medical fields are discussed in this review. Besides background information is provided for beginners for better understanding of the subject.

Non-invasive and quantitative assessment of sudomotor function for peripheral diabetic neuropathy evaluation

AIMS

Perturbation of pain sensation is considered one of the major initiating risk factors for diabetic foot ulcer. Sweat dysfunction leading to abnormal skin conditions, including dryness and fissures, can increase foot ulcer risk. The aim of this study was to evaluate Sudoscan™, a new, quick, non-invasive and quantitative method of measuring sudomotor dysfunction as a co-indicator of the severity of diabetic polyneuropathy (DPN).

METHODS

A total of 142 diabetic patients (age 62±18 years, diabetes duration 13±14 years, HbA(1c) 8.9±2.5%) were measured for vibration perception threshold (VPT), using a biothesiometer, and for sudomotor dysfunction, using electrochemical sweat conductance (ESC) based on the electrochemical reaction between sweat chloride and electrodes in contact with the hands and feet. Retinopathy status was also assessed, as well as reproducibility between two ESC measurements and the effect of glycaemia levels.

RESULTS

ESC measurements in the feet of patients showed a descending trend from 66±17 μS to 43±39 μS, corresponding to an ascending trend in VPT threshold from <15 V to >25 V (P=0.001). Correlation between VPT and ESC was -0.45 (P<0.0001). Foot ESC was lower in patients with fissures, while VPT was comparable. Both VPT and foot ESC correlated with retinopathy status. Bland-Altman plots indicated good reproducibility between two measurements, and between low and high glycaemia levels.

CONCLUSION

Sudoscan™ is a reproducible technique with results that are not influenced by blood glucose levels. Sweating status may be a quantitative indicator of the severity of polyneuropathy that may be useful for the early prevention of foot skin lesions.

An overview of temperature monitoring devices for early detection of diabetic foot disorders

Diabetic foot complications are associated with substantial costs and loss of quality of life. This article gives an overview of available and emerging devices for the monitoring of foot temperature as a means of early detection of foot disorders in diabetes. The aim is to describe the technologies and to summarize experiences from experimental use. Studies show that regular monitoring of foot temperature may limit the incidence of disabling conditions such as foot ulcers and lower-limb amputations. Infrared thermometry and liquid crystal thermography were identified as the leading technologies in use today. Both technologies are feasible for temperature monitoring of the feet and could be used as a complement to current practices for foot examinations in diabetes.

A thermal stereoscope for surface reconstruction of the diabetic foot

We have constructed a thermal stereoscope utilizing three digital SLR cameras and an infrared camera for rapid surface reconstruction of diabetic foot geometry and temperature distribution. A structured light pattern is projected on to the foot to provide approximately 2500 reconstructed points. The reconstructed point cloud is then fitted to a finite element model, producing root mean squared errors of less than 0.4 mm.

Correlation between plantar foot temperature and diabetic neuropathy: a case study by using an infrared thermal imaging technique

BACKGROUND

Diabetic neuropathy consists of multiple clinical manifestations of which loss of sensation is most prominent. High temperatures under the foot coupled with reduced or complete loss of sensation can predispose the patient to foot ulceration. The aim of this study was to look at the correlation between plantar foot temperature and diabetic neuropathy using a noninvasive infrared thermal imaging technique.

METHODS

Infrared thermal imaging, a remote and noncontact experimental tool, was used to study the plantar foot temperatures of 112 subjects with type 2 diabetes selected from a tertiary diabetes centre in South India.

RESULTS

Patients with diabetic neuropathy (defined as vibration perception threshold (VPT) values on biothesiometry greater than 20 V) had a higher foot temperature (32-35 °C) compared to patients without neuropathy (27-30 °C). Diabetic subjects with neuropathy also had higher mean foot temperature (MFT) (p=.001) compared to non-neuropathic subjects. MFT also showed a positive correlation with right great toe (r=0.301, p=.001) and left great toe VPT values (r=0.292, p=.002). However, there was no correlation between glycated hemoglobin and MFT.

CONCLUSIONS

Infrared thermal imaging may be used as an additional tool for evaluation of high risk diabetic feet.

The application of temperature measurement of the eyes by digital infrared thermal imaging as a prognostic factor of methylprednisolone pulse therapy for Graves' ophthalmopathy

PURPOSE

Graves' ophthalmopathy (GO) involves autoimmune process resulting in proptosis, congestion, oedema and diplopia. Werner's NOSPECS classification and clinical activity score (CAS) of GO cannot objectively describe the inflammatory status. Digital infrared thermal imaging (DITI) detects local temperature and may reflect the degree of orbital inflammation. The aim of this study was to evaluate the clinical application of the eye temperature measured by DITI.

METHODS

Forty-six patients with GO receiving intravenously methylprednisolone pulse therapy (MPT) were included in this study. Local temperatures of the lateral orbit, upper eyelid, inner caruncle, medial conjunctiva, lateral conjunctiva, lower eyelid and cornea were measured with DITI before and after MPT. CAS, proptosis, eye movement (EOM) and diplopia were also recorded. Improvement of CAS was defined as at least one point decrease at either side of the eye, which was 0.5 score decrease as to the average of bilateral CAS.

RESULTS

Local temperatures of the eyes decreased after MPT. The mean value of temperature (MT) of 12 points including the lateral orbit, upper eyelid, inner caruncle, medial conjunctiva, lateral conjunctiva and lower eyelid of both eyes before MPT was 32.65 degrees . The mean change of MT after MPT (DeltaT) was -0.22 degrees. DeltaT significantly negative-correlated with basal MT (correlation coefficient=-0.54, p=0.004). Higher baseline MT and CAS before MPT correlated with higher possibility of improvement of CAS after MPT (p=0.013 and 0.012, respectively). Baseline MT and CAS together correlated with improvement of CAS after MPT better than baseline CAS alone could do (area under the receiver operating characteristic curve: 82.81% and 66.63%, respectively).

CONCLUSIONS

Basal temperature of the eyes measured by DITI was an objective indicator of inflammation of GO. Combining CAS and MT could better predict the outcome of MPT than CAS alone.

Feasibility of a thermographic method for early detection of foot disorders in diabetes

BACKGROUND

Foot complications due to diabetes impose a major economic burden to society and loss of health-related quality of life for the patients. Early diagnosis and intensified preventive measures have proved useful to limit the incidence of foot ulcers and lower limb amputations in diabetes, and the development of new tools for early diagnosis has therefore become an attractive option. This article covers a feasibility study of the SpectraSole (Linköping, Sweden) Pro 1000 foot indicator, an innovation based on liquid crystal thermography. The technology identifies increases in temperature, a known indicator of inflammation.

METHODS

Sixty-five patients with diagnosed diabetes were examined with the foot indicator immediately after their ordinary foot examinations according to current practice, and findings from the two investigations were compared.

RESULTS

Sixty-nine examinations were performed. The foot indicator identified increased temperature in 31 cases, of which six had not been detected in the preceding ordinary examinations. The instrument was perceived as easy to use, and the thermographs could be used to visualize problem areas of the foot, which might contribute to better compliance with therapeutic advice.

CONCLUSIONS

The foot indicator detected a relatively high share of the different types of complications but not all. It can be used as a complement to current practices for foot examination. The instrument provides rapid imaging of the foot temperature, and the study indicates that it yields valuable diagnostic information in early stages of foot disease.

Pulsed infrared light therapy does not increase nitric oxide concentration in the blood of patients with type 1 and type 2 diabetes mellitus

The purpose of this study was to determine if NO blood concentrations increased acutely following an 8-week course of pulsed infrared light therapy (PILT) which could be linked to an improvement in peripheral protective sensation (PPS) in patients who have profound chronic diabetic peripheral neuropathy. A total of 22 subjects with the diagnosis of type 1 (N = 2) or type 2 (N = 20) diabetes participated in the study. PILT was administered to one foot chosen at random with the other foot serving as a within-subject control (no treatment). Patients underwent 24 treatments (3 times/week, for 8 weeks) for 30 min per treatment. Venous blood samples were taken during the last 5 min of treatment from veins in the dorsum of the control and experimental feet and were later analyzed for NO concentration. Contrary to the popular supposition, PILT treatments actually resulted in a significantly (P < 0.05) decreased concentration of NO. Additionally, there were no significant differences between the treated and untreated feet. Since in individuals where PILT has significantly improved PPS, PILT did not stimulate an increased NO content in the blood, it appears that infrared light improves peripheral protective sensation in patients by a mechanism other than an increased NO production.