A systematic review on the role of infrared thermography in the Brown adipose tissue assessment

Lightweight convolutional neural network (CNN) model for obesity early detection using thermal images

Objective

The presence of a lightweight convolutional neural network (CNN) model with a high-accuracy rate and low complexity can be useful in building an early obesity detection system, especially on mobile-based applications. The previous works of the CNN model for obesity detection were focused on the accuracy performances without considering the complexity size. In this study, we aim to build a new lightweight CNN model that can accurately classify normal and obese thermograms with low complexity sizes.

Methods

The DenseNet201 CNN architectures were modified by replacing the standard convolution layers with multiple depthwise and pointwise convolution layers from the MobileNet architectures. Then, the depth network of the dense block was reduced to determine which depths were the most comparable to obtain minimum validation losses. The proposed model then was compared with state-of-the-art DenseNet and MobileNet CNN models in terms of classification performances, and complexity size, which is measured in model size and computation cost.

Results

The results of the testing experiment show that the proposed model has achieved an accuracy of 81.54% with a model size of 1.44 megabyte (MB). This accuracy was comparable to that of DenseNet, which was 83.08%. However, DenseNet's model size was 71.77 MB. On the other hand, the proposed model's accuracy was higher than that of MobileNetV2, which was 79.23%, with a computation cost of 0.69 billion floating-point operations per second (GFLOPS), which approximated that of MobileNetV2, which was 0.59 GFLOPS.

Conclusions

The proposed model inherited the feature-extracting ability from the DenseNet201 architecture while keeping the lightweight complexity characteristic of the MobileNet architecture.

Both caffeine and Capsicum annuum fruit powder lower blood glucose levels and increase brown adipose tissue temperature in healthy adult males

Using a combination of respiratory gas exchange, infrared thermography, and blood glucose (BGL) analysis, we have investigated the impact of Capsicum annuum (C. annuum) fruit powder (475 mg) or caffeine (100 mg) on metabolic activity in a placebo controlled (lactose, 100 mg) double-blinded three-way cross-over-design experiment. Metabolic measurements were made on day 1 and day 7 of supplementation in eight adult male participants (22.2 ± 2 years of age, BMI 23 ± 2 kg/m², x̅ ± SD). Participants arrived fasted overnight and were fed a high carbohydrate meal (90 g glucose), raising BGL from fasting baseline (4.4 ± 0.3 mmol/L) to peak BGL (8.5 ± 0.3 mmol/L) 45 min after the meal. Participants consumed the supplement 45 min after the meal, and both caffeine and C. annuum fruit powder restored BGL (F _(8,178) = 2.2, p = 0.02) to near fasting levels within 15 min of supplementation compared to placebo (120 min). In parallel both supplements increased energy expenditure (F _{(2, 21)} = 175.6, p < 0.001) over the 120-min test period (caffeine = 50.74 ± 2 kcal/kg/min, C. annuum fruit = 50.95 ± 1 kcal/kg/min, placebo = 29.34 ± 1 kcal/kg/min). Both caffeine and C. annuum fruit powder increased supraclavicular fossa temperature (F _(2,42) = 32, p < 0.001) on both day 1 and day 7 of testing over the 120-min test period. No statistical difference in core temperature or reference point temperature, mean arterial pressure or heart rate was observed due to supplementation nor was any statistical difference seen between day 1 and day 7 of intervention. This is important for implementing dietary ingredients as potential metabolism increasing supplements. Together the results imply that through dietary supplements such as caffeine and C. annuum, mechanisms for increasing metabolism can be potentially targeted to improve metabolic homeostasis in people.

Raman studies of the adipose tissue: Current state-of-art and future perspectives in diagnostics

The last decades revealed that the adipose tissue shows an unexplored therapeutic potential. In particular, targeting the perivascular adipose tissue (PVAT), that surrounds blood vessels, can prevent cardiovascular pathologies and browning of the adipose tissue can become an effective strategy against obesity. Therefore, new analytical tools are necessary to analyze this tissue. This review reports on the recent developments of various Raman-based techniques for the identification and quantification of the adipose tissue compared to conventional analytical methods. In particular, the emphasis is on analysis of PVAT, investigation of pathological changes of the adipose tissue in model systems and possibilities for its characterization in the clinical context. Overall, the review critically discusses the potential and limitations of Raman techniques in adipose tissue-targeted diagnostics and possible future anti-obesity therapies.

A Preliminary Study on Infrared Thermograph of Metabolic Syndrome

OBJECTIVE

To explore the temperature distribution characteristics of the face, palms, feet and the trunk area of metabolic syndrome (MS) through infrared thermography (IRT) and provide evidence for the application of IRT in the assistant evaluation of MS population.

METHODS

We collected thermographs of 184 participants (91 males, 93 females) and further divided participants of each gender into 4 groups according to the number of abnormal metabolic indexes. Mean temperatures of 6 Region of Interests (ROIs) (face, anterior trunk, bilateral palms and dorsum of feet) were calculated. Comparisons of the mean temperatures between genders, among groups and ROIs were carried out.

RESULTS

Male participants had higher mean temperature in their face, palms (P<0.01) and dorsum of feet (P<0.05), and lower mean temperature in the anterior trunk (P<0.01). Female participants with MS had higher mean temperature in their palms and dorsum of feet (P<0.01) and lower mean temperature in the anterior trunk (P<0.01) than normal participants. Similar tendencies were shown in the mean temperature of the left palms and trunk of MS males. With the increase of the number of abnormal metabolic indexes, it seems that the mean temperature gradually increased in palms and dorsum of feet, and decreased in the anterior trunk.

CONCLUSION

The thermograph of MS exhibits certain characteristics. This may help reveal the correlations between Infrared thermography and metabolic disorders.

Altered brown fat thermoregulation and enhanced cold-induced thermogenesis in young, healthy, winter-swimming men

The Scandinavian winter-swimming culture combines brief dips in cold water with hot sauna sessions, with conceivable effects on body temperature. We study thermogenic brown adipose tissue (BAT) in experienced winter-swimming men performing this activity 2–3 times per week. Our data suggest a lower thermal comfort state in the winter swimmers compared with controls, with a lower core temperature and absence of BAT activity. In response to cold, we observe greater increases in cold-induced thermogenesis and supraclavicular skin temperature in the winter swimmers, whereas BAT glucose uptake and muscle activity increase similarly to those of the controls. All subjects demonstrate nocturnal reduction in supraclavicular skin temperature, whereas a distinct peak occurs at 4:30–5:30 a.m. in the winter swimmers. Our data leverage understanding of BAT in adult human thermoregulation, suggest both heat and cold acclimation in winter swimmers, and propose winter swimming as a potential strategy for increasing energy expenditure.

Winter swimmers have a lower core temperature at a thermal comfort state than controls

Winter swimmers had no BAT glucose uptake at a thermal comfort state

Winter swimmers have higher cold-induced thermogenesis than control subjects

Human supraclavicular skin temperature varies with a diurnal rhythm

Predicting lipoabdominoplasty complications with infrared thermography: a delta-R analysis

The diagnosis of the main complications resulting from lipoabdominoplasty has not yet been standardized. Infrared thermal imaging has been used to assess possible complications, such as necrosis and changes in micro- and macro-circulation, based on perforator mapping techniques, among others. The objective of this study was to present two clinical cases involving thermal imaging monitoring of the healing process of lipoabdominoplasty in the immediate postoperative evaluation and its preliminary results. Infrared thermography was performed 24 hours after the operation and on postoperative days 5, 25, and 27. In clinical case 1, it was found that the delta-R (∆TR)-defined as the difference in minimum temperature between the highest and lowest points in the SA3 region (caution suction area) following the classification established by Matarasso-was 0.4°C at 24 hours after surgery and decreased to 0.1°C on a postoperative day 5. There were no complications in this case. In contrast, in clinical case 2, the ∆TR was 1.7°C at 24 hours after surgery (upon hospital discharge) and remained high, at 2.2°C, on postoperative day 5. A higher ∆TR was found in the second patient, who developed necrosis of the surgical wound. The ∆TR thermal index may be a new tool for predicting possible complications, complementing the clinical evaluation and therapeutic decision-making.

Investigation of thermal changes in the thyroid gland region of individuals with hypothyroidism and fibromyalgia by analyzing the temperature of brown adipose tissue

This exploratory retrospective study aims to investigate the thermal changes in the thyroid gland region of patients with hypothyroidism and fibromyalgia by analyzing the temperature of the brown adipose tissue (BAT). A total of 166 individuals from 1000 thermographic electronic medical records were classified into four groups: Group HP + FM-50 individuals with hypothyroidism and fibromyalgia; Group FM-56 individuals with fibromyalgia only; Group HP-30 individuals with hypothyroidism only, and Group Control-30 healthy individuals. The thermal images from the electronic medical records were acquired by a FLIR T650SC infrared camera (used for thermometry) and the temperature data for each group were statistically analyzed. Group HP + FM showed r = 0, meaning that the average temperatures of the thyroid and BAT are independent of each other. Groups FM, HP and Control showed r = 1, meaning that the average temperatures of the thyroid and BAT were directly related. Our findings showed that the average temperatures of the thyroid and BAT regions are similar. Also, there was no correlation between thyroid gland temperature and the presence of hypothyroidism or fibromyalgia using thermometry.