Melting temperature mapping method in children: Rapid identification of pathogenic microbes

INTRODUCTION

The melting temperature (Tm) mapping method (TM) identifies bacterial species by intrinsic patterns of Tm values in the 16S ribosomal RNA gene (16S rDNA) extracted directly from whole blood. We examined potential clinical application of TM in children with bloodstream infection (BSI).

METHODS

This was a prospective observational study at a children's hospital in Japan from 2018 to 2021. In patients with diagnosed or suspected BSI, we investigated the match rates of pathogenic bacteria identified by TM and blood culture (BC), the inspection time to identification of TM, and the amount of bacterial DNA in blood samples.

RESULTS

The median age of 81 patients (93 samples) was 3.6 years. Of 23 samples identified by TM, 11 samples matched the bacterial species with BC (positive-match rate, 48 %). Of 64 TM-negative samples, 62 samples were negative for BC (negative-match rate, 97 %). Six samples, including one containing two pathogenic bacterial species, were not suitable for TM identification. In total, the matched samples were 73 of 93 samples (match rate, 78 %). There were seven samples identified by TM in BC-negative samples from blood collected after antibiotic therapy. Interestingly, the bacteria were matched with BC before antibiotic administration. These TM samples contained as many 16S rDNA copies as the BC-positive samples. The median inspection time to identification using TM was 4.7 h.

CONCLUSIONS

In children with BSI, TM had high negative-match rates with BC, the potential to identify the pathogenic bacteria even in patients on antibiotic therapy, and more rapid identification compared to BC.

REGISTERING CLINICAL TRIALS

UMIN000041359https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000047220.

Breathing mode assessment with thermography: a pilot study

PURPOSE

To present a method for analyzing breathing modes with infrared thermography.

METHODS

This exploratory cross-sectional study used 38 thermal images of inspiration and expiration with nasal breathing and simulated mouth breathing in four nasal breathers without respiratory complaints. Three different data selection forms (line, rectangle, and ellipse) were used to extract the minimum, mean, and maximum temperatures of the regions of interest (nose and mouth) using the FLIR Tools® software.

RESULTS

Among the three selection forms, there was greater temperature variability obtained with the line, revealing limitations in this measurement. There were no differences between the rectangle and ellipse values, showing that both selection forms present similar temperature extraction results. The comparison results between nose and mouth temperatures during inspiration and expiration indicated a statistically significant difference between all measurements, except for mean inspiration temperatures with the rectangle and ellipse. The breathing mode can be distinguished in both inspiration and expiration when using mean mouth temperatures with the rectangle and ellipse.

CONCLUSION

Breathing modes should be assessed based on mean mouth temperatures during inspiration, using the ellipse.

Exploring the body surface temperature of the lumbosacral region and relevant back-shu points in patients with lumbar disc herniation induced low back pain based on infrared thermography

OBJECTIVES

To observe the body surface temperature of the lumbosacral region and relevant back-shu points in patients with lumbar disc herniation (LDH) induced low back pain utilizing infrared thermography, and to explore the functional attribute changes of acupoints under pathological conditions.

METHODS

A total of 50 patients with LDH induced low back pain were included as the observation group, and 45 healthy subjects were included as the control group. Using infrared thermography, the body surface temperature of the lumbosacral region and bilateral Sanjiaoshu (BL 22), Shenshu (BL 23), Qihaishu (BL 24), Dachangshu (BL 25), Guanyuanshu (BL 26), Xiaochangshu (BL 27), and Pangguangshu (BL 28) was measured in both groups. The temperature difference values between the bilateral lumbosacral regions and back-shu points of the two groups were calculated. Additionally, the body surface temperature of the affected and healthy sides of the lumbosacral region and relevant back-shu points was compared in the observation group.

RESULTS

Compared with the control group, the body surface temperature of the lumbosacral region and the bilateral temperature difference values of the lumbosacral regions were increased in the observation group (P<0.001). The body surface temperature difference values of bilateral Shenshu (BL 23), Qihaishu (BL 24), Dachangshu (BL 25), Guanyuanshu (BL 26) and Xiaochangshu (BL 27) in the observation group were higher than those in the control group (P<0.05, P<0.01, P<0.001). In the observation group, the body surface temperature of the affected side of the lumbosacral region as well as Shenshu (BL 23) and Dachangshu (BL 25) was elevated compared with that of healthy side (P<0.001).

CONCLUSIONS

The patients with LDH induced low back pain have imbalanced and asymmetrical distribution of body surface temperature in the lumbosacral region and related back-shu points, Shenshu (BL 23) and Dachangshu (BL 25) have the relative specificity.

Generative adversarial network: a statistical-based deep learning paradigm to improve detecting breast cancer in thermograms

Thermography, as a harmless modality, thanks to its low equipment complexity in parallel with quick and cheap access, has been able to come up as a method with significant potential in the diagnosis of some cancers in recent years. However, the complexity of the images resulting from this method has caused the use of deep learning to interpret thermograms. A limiting factor in this process is the strong dependence of deep learning methods on the number of training data, which is a serious challenge in thermography due to the young age of this technology and the lack of available images. In this paper, an attempt is made to reduce the above challenge by utilizing the concept of statistical learning in such a way that the statistical distribution of the original data is estimated by using generative adversarial networks (i.e., GAN). Then, several fake images are reconstructed based on the estimated distribution in order to increase the training thermograms. Since the fake images are reconstructed based on similar statistics of real thermograms in each class, the effective features of each class are preserved to a significant extent in the reconstruction process. The use of this method indicates a significant improvement in the separation of healthy and cancerous thermograms compared to the benchmark method which does not use the concept of GAN in such a way that characteristics of sensitivity and accuracy are improved in ranges of 3-9% and 3-7%, respectively. In terms of specificity, although we have seen an improvement of up to 9%, in some cases, small drops of up to 2% have also been observed, which can still be justified due to the significant improvement in sensitivity and accuracy.

Thermography and conversion of fast-cure composite photocured with quad-wave and laser curing lights compared to a conventional curing light

OBJECTIVES

This study investigated effects of the different emittance-mode protocols from three light curing units (LCUs): (i) a Laser (Monet); (ii) a quad-wave (PinkWave); (iii) a conventional LED (Elipar S10) on the temperature rise (ΔT) and degree of conversion (DC) when photo-curing fast or conventional bulk-fill resin-based composites (RBC). The aim was to correlate ΔT and DC, and the radiant exposure delivered to RBC specimens.

METHODS

A 3D-printed resin mold of 4 mm depth was filled with two bulk-fill RBCs: Tetric PowerFill® (fast photo-polymerised composite) (TPF) or Tetric EvoCeram® Bulk-Fill (EVO). Three LCUs were used: (i) Monet laser for 1 s and 3 s (MONET-1 s, MONET-3 s); (ii) PinkWave quad-wave used for 3 s in Boost mode (PW-3 s) and for 20 s in standard mode (PW-20 s); (iii) Elipar S10 for 5 s (S10-5 s) and for 20 s in standard mode (S10-20 s). 2-dimensional temperature maps were obtained before, during and for 60 s after the LCU had turned off using a thermal imaging camera. Thermal changes were analysed at five depths: (0, 1, 2, 3, and 4 mm from the top surface of the RBC). The maximum temperature rise (Tmax) and the mean temperature rise (ΔT) were determined. Cylindrical-shaped specimens were prepared from each material using a stainless-steel split mold (4 × 4 mm) and light-cured with the same protocols. The DC was measured for 120 s and at 1 h after LCU had turned off using Fourier Transform Infrared Spectroscopy (FTIR). Data were analysed using Three-way ANOVA, One-way ANOVA, independent t-tests, and Tukey post-hoc tests (p < 0.05).

RESULTS

Radiant exposures delivered by the various irradiation protocols were between 4.5-30.3 J/cm2. Short exposure times from MONET-1 s and PW-3 s delivered the lowest radiant exposures (4.5 and 5.2 J/cm2, respectively) and produced the lowest ΔT and DC. The longer exposure times in the standard modes of PW-20 s, S10-20 s, and MONET-3 s produced the highest Tmax, ΔT, and DC for both composites. The ΔT range among composites at different depths varied significantly (31.7-49.9 °C). DC of TPF ranged between 30-65% and in EVO between 15.3-56%. TPF had higher Tmax, ΔT for all depths and DC compared to EVO, across the LCU protocols (p < 0.05), except for PW-20 s and MONET-3 s. The coronal part of the restorations (1-2 mm) had the highest ΔT. There was a positive correlation between ΔT and DC at 4-mm depth after 120 s SIGNIFICANCE: Longer, or standard, exposure times of the LCUs delivered greater radiant exposures and had higher DC and ΔT compared to shorter or high-irradiance protocols. The fast photo-polymerised RBC had comparatively superior thermal and conversion outcomes when it received a high irradiance for a short time (1-5 s) compared to the conventional Bulk-Fill RBC.

Temperature rise in photopolymerized adhesively-bonded resin composite: A thermography study

OBJECTIVES

To assess visually and quantitatively the contributions of the adhesive layer photopolymerization and the subsequent resin composite increment to spatio-temporal maps of temperature at five different cavity locations, subjected to two irradiance curing protocols: standard and ultra-high.

METHODS

Caries-free molars were used to obtain 40, 2 mm thick dentin slices, randomly assigned to groups (n = 5). These slices were incorporated within 3D-printed model cavites, 4 mm deep, restored with Adhese® Universal bonding agent and 2 mm thick Tetric® Powerfill resin composite, and photocured sequentially, as follows: G1: control-empty cavity; G2: adhesive layer; G3 composite layer with no adhesive; and G4 composite layer with adhesive. The main four groups were subdivided based on two curing protocols, exposed either to standard 10 s (1.2 W/cm2) or Ultra high 3 s (3 W/cm2) irradiance modes using a Bluephase PowerCure LCU. Temperature maps were obtained, via a thermal imaging camera, and numerically analyzed at 5 locations. The data were analyzed using two-way ANOVA followed by multiple one-way ANOVA, independent t-tests and Tukey post-hoc tests (α = 0.05). Tmax, ΔT, Tint (integrated area under the curve) and time-to-reach-maximum-temperature were evaluated.

RESULTS

Two-way ANOVA showed that there was no significant interaction between light-curing time and location on the measured parameters (p > 0.05), except for the time-to-reach-maximum-temperature (p < 0.05). Curing the adhesive layer alone with the 10 s protocol resulted in a significantly increased pulpal roof temperature compared to 3 s cure (p < 0.05). Independent T-tests between G3 and G4, between 3 s and 10 s, confirmed that the adhesive agent caused no significant increases (p > 0.05) on the measured parameters. The ultra-high light-curing protocol significantly increased ΔT in composite compared to 10 s curing (p < 0.05).

SIGNIFICANCE

When the adhesive layer was photocured alone in a cavity, with a 2 mm thick dentin floor, the exothermal release of energy resulted in higher temperatures with a 10 s curing protocol, compared to a 3 s high irradiance. But when subsequently photocuring a 2 mm layer of composite, the resultant temperatures generated at pulpal roof location from the two curing protocols were similar and therefore there was no increased hazard to the dental pulp from the immediately prior adhesive photopolymerization, cured via the ultra-high irradiation protocol.

Update on the Use of Infrared Thermography in the Early Detection of Diabetic Foot Complications: A Bibliographic Review

Foot lesions are among the most frequent causes of morbidity and disability in the diabetic population. Thus, the exploration of preventive control measures is vital for detecting early signs and symptoms of this disease. Infrared thermography is one of the complementary diagnostic tools available that has proven to be effective in the control of diabetic foot. The last review on this topic was published in 2015 and so, we conducted a bibliographic review of the main databases (PubMed, the Web of Science, Cochrane library, and Scopus) during the third quarter of 2023. We aimed to identify the effectiveness of infrared thermography as a diagnostic element in pre-ulcerous states in diabetic patients and to detect diabetic foot ulcer complications. We obtained a total of 1199 articles, 26 of which were finally included in the present review and published after 2013. After analyzing the use of infrared thermography in diabetic patients both with and without ulcers, as well as in healthy individuals, we concluded that is an effective tool for detecting early-stage ulcers in diabetic foot patients.

Region-wise severity analysis of diabetic plantar foot thermograms

OBJECTIVES

Diabetic foot ulcers (DFU) can be avoided if symptoms of diabetic foot complications are detected early and treated promptly. Early detection requires regular examination, which might be limited for many reasons. To identify affected or potentially affected regions in the diabetic plantar foot, the region-wise severity of the plantar foot must be known.

METHODS

A novel thermal diabetic foot dataset of 104 subjects was developed that is suitable for Indian healthcare conditions. The entire plantar foot thermogram is divided into three parts, i.e., forefoot, midfoot, and hindfoot. The division of plantar foot is based on the prevalence of foot ulcers and the load on the foot. To classify the severity levels, conventional machine learning (CML) techniques like logistic regression, decision tree, KNN, SVM, random forest, etc., and convolutional neural networks (CNN), such as EfficientNetB1, VGG-16, VGG-19, AlexNet, InceptionV3, etc., were applied and compared for robust outcomes.

RESULTS

The study successfully developed a thermal diabetic foot dataset, allowing for effective classification of diabetic foot ulcer severity using the CML and CNN techniques. The comparison of different methods revealed variations in performance, with certain approaches outperforming others.

CONCLUSIONS

The region-based severity analysis offers valuable insights for targeted interventions and preventive measures, contributing to a comprehensive assessment of diabetic foot ulcer severity. Further research and development in these techniques can enhance the detection and management of diabetic foot complications, ultimately improving patient outcomes.

Use of Infrared Thermography in Medical Diagnosis, Screening, and Disease Monitoring: A Scoping Review

Thermography provides non-invasive, radiation-free diagnostic imaging. Despite the extensive literature on medical thermography, a comprehensive overview of current applications is lacking. Hence, the aim of this scoping review is to identify the medical applications of passive infrared thermography and to catalogue the technical and environmental modalities. The diagnostic performance of thermography and the existence of specific reference data are evaluated, and research gaps and future tasks identified. The entire review process followed the Joanna Briggs Institute (JBI) approach and the results are reported according to PRISMA-ScR guidelines. The scoping review protocol is registered at the Open Science Framework (OSF). PubMed, CENTRAL, Embase, Web of Science, OpenGrey, OSF, and PROSPERO were searched using pretested search strategies based on the Population, Concept, Context (PCC) approach. According to the eligibility criteria, references were screened by two researchers independently. Seventy-two research articles were identified describing screening, diagnostic, or monitoring studies investigating the potential of thermography in a total of 17,314 participants within 38 different health conditions across 13 therapeutic areas. The use of several camera models from various manufacturers is described. These and other facts and figures are compiled and presented in a detailed, descriptive tabular and visual format. Thermography offers promising diagnostic capabilities, alone or in addition to conventional methods.

The application of infrared thermography technology in flap: A perspective from bibliometric and visual analysis

The application of infrared thermography technology (IRT) in flap has become a major focus of research, as it provides a non-invasive, real-time, and quantitative approach for monitoring flap perfusion. In this regard, we conducted a comprehensive visualization and scientometric analysis to systematically summarize and discuss the current state of research in this field. We systematically reviewed publications on the application of IRT in flap procedures from 1999 to 2022, using the Web of Science Core Collection (WoSCC). Through scientometric analysis, we examined annual trends, affiliations, countries, journals, authors, and their relationships, providing insights into current hotspots and future developments in this area. We analysed 522 English studies and found a steady increase in annual publications. The United States and Germany had the highest publication rates, with Beth Israel Deaconess Medical Center and Shanghai Jiaotong University being leading institutions. Notably, Lee BT and Alex Keller emerged as influential authors in this field. Compared to existing techniques, infrared-based technology offers significant advantages for non-invasive monitoring of flap perfusion, including simplicity of operation and objective results. Future trends should focus on interdisciplinary collaborations to develop new infrared devices and achieve intelligent image processing, enabling broader application in various clinical scenarios. This bibliometric study summarizes the progress and landscape of research on 'the Application of infrared thermography technology in flap' over the past two decades, providing valuable insights and serving as a reliable reference to drive further advancements and spark researchers' interest in this field.

Thermographic examination of gingival phenotypes: correlation between morphological and thermal parameters

OBJECTIVES

To evaluate the clinical and thermographic aspects of the gingival phenotype (GP) in healthy subjects.

MATERIALS AND METHODS

The study sample examined 264 teeth, upper and lower incisors, comprising 132 central incisors (CI) and 132 lateral incisors (LI), in 33 healthy volunteers. Four periodontal parameters were recorded systematically: ratio of width to length of the dental crown (CW/CL), height of the gingival attachment (KGW), probing depth (PD), and gingival transparency (GT). The temperatures of the attached gingiva (KGW temp) and the free gingival margin (FGM Temp) were also recorded by way of infrared thermography (IRT).

RESULTS

The average age of the sample was 30.70 ± 7.65 years. Of the 264 teeth evaluated, 76.1% had a thin GP. There was a significant association between CW/CL (p < 0.001), KGW (p < 0.001), PD (p < 0.007), and FGM Temp (p < 0.006) with the tooth groups. The results show a significant and inversely proportional correlation between clinical parameters and gingival temperature (p < 0.05). A significant association was found between CW/CL (p < 0.026); KGW (p < 0.001); and GP.

CONCLUSION

CW/CL, KGW, PD, and FGM Temp vary according to tooth group. The majority of the sample presented with the thin GP, which was more prevalent in the lower LIs and CIs. No significant association could be observed between thermographic parameters and GP.

CLINICAL RELEVANCE

Knowledge of the temperature of the gingival tissues can be useful in helping to diagnose and plan periodontal treatments. Moreover, our findings will help future studies evaluate the use of IR as an auxiliary diagnostic method in dentistry, eliminating GP as a confounding factor, since it does not seem to influence the temperature of the gingival tissues.

Comparing the ocular surface temperature and dry eye condition of keratoconus with normal eyes using infrared thermal imaging

PURPOSE

This study was conducted to compare the ocular surface temperature in keratoconus eyes with that in normal eyes.

METHODS

A total of 27 participants were enrolled, with 10 and 17 participants in the keratoconus and control groups, respectively. Participants in the control group underwent an ophthalmic slit lamp examination and ocular thermography, while an additional corneal tomography was performed for those in the keratoconus group.

RESULTS

For patients with keratoconus, the mean upper eyelid temperature (UET) was 32.36 ± 1.02 °C, inner canthus temperature (ICT) was 34.25 ± 0.83 °C, outer canthus temperature (OCT) was 33.62 ± 0.96 °C, initial central corneal temperature (initial CCT) was 33.04 ± 1.03 °C, sixth-second CCT (6 s-CCT) was 32.67 ± 1.19 °C, and the mean change in CCT measured within 6 s (change in CCT within 6 s) was 0.36 ± 0.26 °C. For controls, the values for UET, ICT, OCT, initial CCT, 6 s-CCT, and change in CCT within 6 s were 32.35 ± 1.13 °C, 34.14 ± 0.91 °C, 33.51 ± 1.02 °C, 33.22 ± 1.01 °C, 32.99 ± 1.01 °C, and 0.22 ± 0.17 °C, respectively. Except for the change in CCT within 6 s (p = 0.022), no significant differences were observed in UET (p = 0.973), ICT (p = 0.659), OCT (p = 0.697), initial CCT (p = 0.556) or 6 s-CCT (p = 0.310) between the two groups.

CONCLUSION

The keratoconus eyes showed faster changes in CCT and evaporation of tear film after opening the eyes. Therefore, the keratoconus eyes had a higher incidence of dry eye conditions.

A robust motion correction technique for infrared thermography during awake craniotomy

PURPOSE

Intraoperative infrared thermography is an emerging technique for image-guided neurosurgery, whereby physiological and pathological processes result in temperature changes over space and time. However, motion during data collection leads to downstream artifacts in thermography analyses. We develop a fast, robust technique for motion estimation and correction as a preprocessing step for brain surface thermography recordings.

METHODS

A motion correction technique for thermography was developed which approximates the deformation field associated with motion as a grid of two-dimensional bilinear splines (Bispline registration), and a regularization function was designed to constrain motion to biomechanically feasible solutions. The performance of the proposed Bispline registration technique was compared to phase correlation, a band-stop filter, demons registration, and the Horn-Schunck and Lucas-Kanade optical flow techniques.

RESULTS

All methods were analyzed using thermography data from ten patients undergoing awake craniotomy for brain tumor resection, and performance was compared using image quality metrics. The proposed method had the lowest mean-squared error and the highest peak-signal-to-noise ratio of all methods tested and performed slightly worse than phase correlation and Demons registration on the structural similarity index metric (p < 0.01, Wilcoxon signed-rank test). Band-stop filtering and the Lucas-Kanade method were not strong attenuators of motion, while the Horn-Schunck method was well-performing initially but weakened over time.

CONCLUSION

Bispline registration had the most consistently strong performance out of all the techniques tested. It is relatively fast for a nonrigid motion correction technique, capable of processing ten frames per second, and could be a viable option for real-time use. Constraining the deformation cost function through regularization and interpolation appears sufficient for fast, monomodal motion correction of thermal data during awake craniotomy.

Psychophysiological responses of shame in young children: A thermal imaging study

Shame can be defined as the emotional response to one's violations of rules being exposed to others. However, it is difficult to objectively measure this concept. This study examined the psychophysiological indicators of shame in young children using behavioral methods and thermography, which measures facial temperatures that reflect blood flow changes related to emotions. Four- to six-year-old children participated in an "animal guessing game," in which they lied about having violated a rule. They were assigned to either the exposure or the non-exposure group. In the exposure group, participants' lies were exposed by the experimenter, whereas in the non-exposure group, their lies were not. Results showed that at the behavioral level, participants in the exposure group expressed characteristic behaviors of shame (e.g., embarrassed smiles) more often than those in the non-exposure group. Moreover, the nasal temperatures of participants in the exposure group were higher than those of participants in the other group after the lie was exposed. These results suggest that participants' lies being exposed induced psychophysiological responses and consequently raised their nasal temperature. This finding indicates that psychophysiological responses can enable us to objectively measure higher-order emotions in young children.

Thermography captures the differential sensitivity of dryland functional types to changes in rainfall event timing and magnitude

Drylands of the southwestern United States are rapidly warming, and rainfall is becoming less frequent and more intense, with major yet poorly understood implications for ecosystem structure and function. Thermography-based estimates of plant temperature can be integrated with air temperature to infer changes in plant physiology and response to climate change. However, very few studies have evaluated plant temperature dynamics at high spatiotemporal resolution in rainfall pulse-driven dryland ecosystems. We address this gap by incorporating high-frequency thermal imaging into a field-based precipitation manipulation experiment in a semi-arid grassland to investigate the impacts of rainfall temporal repackaging. All other factors held constant, we found that fewer/larger precipitation events led to cooler plant temperatures (1.4°C) compared to that of many/smaller precipitation events. Perennials, in particular, were 2.5°C cooler than annuals under the fewest/largest treatment. We show these patterns were driven by: increased and consistent soil moisture availability in the deeper soil layers in the fewest/largest treatment; and deeper roots of perennials providing access to deeper plant available water. Our findings highlight the potential for high spatiotemporal resolution thermography to quantify the differential sensitivity of plant functional groups to soil water availability. Detecting these sensitivities is vital to understanding the ecohydrological implications of hydroclimate change.

Breast cancer pre-clinical screening using infrared thermography and artificial intelligence: a prospective, multicentre, diagnostic accuracy cohort study

BACKGROUND

Given the limited access to breast cancer (BC) screening, the authors developed and validated a mobile phone-artificial intelligence-based infrared thermography (AI-IRT) system for BC screening.

MATERIALS AND METHODS

This large prospective clinical trial assessed the diagnostic performance of the AI-IRT system. The authors constructed two datasets and two models, performed internal and external validation, and compared the diagnostic accuracy of the AI models and clinicians. Dataset A included 2100 patients recruited from 19 medical centres in nine regions of China. Dataset B was used for independent external validation and included 102 patients recruited from Langfang People's Hospital.

RESULTS

The area under the receiver operating characteristic curve of the binary model for identifying low-risk and intermediate/high-risk patients was 0.9487 (95% CI: 0.9231-0.9744) internally and 0.9120 (95% CI: 0.8460-0.9790) externally. The accuracy of the binary model was higher than that of human readers (0.8627 vs. 0.8088, respectively). In addition, the binary model was better than the multinomial model and used different diagnostic thresholds based on BC risk to achieve specific goals.

CONCLUSIONS

The accuracy of AI-IRT was high across populations with different demographic characteristics and less reliant on manual interpretations, demonstrating that this model can improve pre-clinical screening and increase screening rates.

Infrared Thermography for Real-Time Assessment of the Effectiveness of Scoliosis Braces

This work proposes an innovative method, based on the use of low-cost infrared thermography (IRT) instrumentation, to assess in real time the effectiveness of scoliosis braces. Establishing the effectiveness of scoliosis braces means deciding whether the pressure exerted by the brace on the patient's back is adequate for the intended therapeutic purpose. Traditionally, the evaluation of brace effectiveness relies on empirical, qualitative assessments carried out by orthopedists during routine follow-up examinations. Hence, it heavily depends on the expertise of the orthopedists involved. In the state of the art, the only objective methods used to confirm orthopedists' opinions are based on the evaluation of how scoliosis progresses over time, often exposing people to ionizing radiation. To address these limitations, the method proposed in this work aims to provide a real-time, objective assessment of the effectiveness of scoliosis braces in a non-harmful way. This is achieved by exploiting the thermoelastic effect and correlating temperature changes on the patient's back with the mechanical pressure exerted by the braces. A system based on this method is implemented and then validated through an experimental study on 21 patients conducted at an accredited orthopedic center. The experimental results demonstrate a classification accuracy slightly below 70% in discriminating between adequate and inadequate pressure, which is an encouraging result for further advancement in view of the clinical use of such systems in orthopedic centers.

Detection of canine obstructive nasal disease using infrared thermography: A pilot study

Infrared thermography detects variations in heat signature and is utilized in other species to non-invasively identify respiratory disease. This study aimed to determine if infrared thermography could be used to detect nasal disease in dogs. Eight dogs presenting for nasal disease (ND group) and ten healthy control dogs (C group) were enrolled. Dorsal and rostral images of the nose were acquired using a Fluke TiX580 60Hz thermal imaging camera. Images were analyzed using the accompanying software. Regions of interest were defined over the right and left nasal passages to determine the maximum (max), average (avg), and minimum (min) temperatures. Temperatures were compared between ND and C groups, and correlation to disease state (ND or C) was evaluated. Temperature differences and imaging patterns were subjectively compared with diagnosis based on computed tomography (CT) and histopathology. The ND group consisted of 5 spayed females and 3 neutered males. Clinical sings included unilateral epistaxis (n = 4); bilateral serous discharge and sneezing (n = 1); bilateral mucopurulent discharge, epistaxis, and sneezing (n = 1); unilateral mucoid discharge, epistaxis and sneezing (n = 1); and sneezing and unilateral epistaxis (n = 1). Temperatures were significantly different between ND and C groups on dorsal (max p = <0.001, avg p = 0.001, min p = <0.001) and rostral (max p = <0.001, avg p = <0.001, min p = 0.005) images. Temperature positively correlated to disease status (ND vs C group) in both dorsal and rostral images. Subjective analysis of images allowed correct identification of abnormal or normal 27/36 times. Obstructive nasal disease results in a local temperature increase in the affected nasal passage that can be non-invasively detected by infrared thermography.

Clinical results of lumbar sympathetic blocks in lower limb complex regional pain syndrome using infrared thermography as a support tool

AIM

To describe the clinical outcomes for a group of complex regional pain syndrome patients using infrared thermography as an intraprocedural support tool when undertaking fluoroscopy-guided lumbar sympathetic blocks.

SUBJECTS

27 patients with lower limb complex regional pain syndrome accompanied by severe pain and persistent functional impairment.

METHODS

A series of three fluoroscopic-guided lumbar sympathetic blocks with local anesthetic and corticoids using infrared thermography as an intraprocedural support tool were performed. Clinical variables were collected at baseline, prior to each block, and one, three, and six months after blocks in a standardized checklist assessing each of the clinical categories of complex regional pain syndrome stipulated in the Budapest criteria.

RESULTS

23.75% of the blocks required more than one chance to achieve the desired thermal pattern and therefore to be considered as successful. A decrease in pain measured on a visual analogic scale was observed at all time points compared to pre-blockade data, but only 37% of the cases were categorized as responders, representing a ≥ 30% decrease in VAS, with the disappearance of pain at rest. An improvement of most of the clinical variables recorded was observed, such as tingling, edema, perception of thermal asymmetry, difference in coloring and sweating. There was a significant decrease of neuropathic pain and improvement of functional limitation. Logistic regression analysis showed the main variable to explain the probability of being a responder was immobilization time (odds ratio of 0.89).

CONCLUSION

A series of fluoroscopy-guided lumbar sympathetic blocks controlled by infrared thermography in the treatment of lower limb CRPS showed a responder rate of 37%.

Infrared Thermography: Clinical Value for Diagnosing Persistent Somatoform Pain Disorders?

BACKGROUND

Patients with persistent somatoform pain disorder (PSPD) are not uncommon. Still, the disease diagnosis relies primarily on structured interviews, with no objective indicators yet available to aid in the diagnosis. This has led to low diagnostic rates and overconsumption of health care resources for the disorder. Although there is a large body of research to improve the diagnosis of the condition, there are currently no objective indicators available for diagnosis.

OBJECTIVES

The aim of this study is to investigate the clinical value of infrared thermography (IRT) for diagnosing PSPD.

STUDY DESIGN

This is a retrospective study.

SETTING

A single academic hospital, outpatient setting.

METHODS

The clinical data of patients diagnosed with PSPD in the Pain Department of the First Affiliated Hospital of the Army Medical University from September 2020 to September 2022 were analyzed. The differences in IR thermograms between PSPD patients and healthy controls were analyzed, as well as the relationship between the Hamilton Depression Rating Scale, Hamilton Anxiety Scale, Pittsburgh Sleep Quality Index (PSQI) score, Patient Health Questionnaire-15, and Symptom Check List-90 and the differences in IR thermograms of PSPD patients.

RESULTS

The mean squared error, structural similarity measure, different hash, contrast, entropy, inverse variance, and correlation values of the IR thermogram helped to determine PSPD with statistically significant differences (P < 0.05). Inverse variance values were weakly negatively correlated with PSQI scores of PSPD patients (r -0.4721, P < 0.05).

LIMITATIONS

This study was limited by its sample size and retrospective observational design.

CONCLUSIONS

IRT analysis is a useful objective method in diagnosis of PSPD, which also provides a new line of thought for studying the pathogenesis of PSPD.

KEY WORDS

Persistent somatoform pain disorder, PSPD, thermal imaging, infrared thermography, IRT, image texture characteristics, psychometric variables, image analysis.

An application based on the analysis of thermograms to calculate the thermographic index for pain and swelling assessment

As the world's population ages, the prevalence of rheumatic diseases is increasing. These diseases are often diagnosed and monitored using imaging techniques such as infrared thermography. In this study, we developed an application to calculate the thermographic index (TI) in a series of thermograms. Such index is used in rheumatology as a complementary diagnostic tool to assess pain and swelling. We designed the application in MATLAB App Designer; an environment for creating applications with a graphical user interface. To evaluate the performance of the developed application, we calculated the TI of ten trigger points (anterior shoulder, sternum, posterior shoulder, upper back, lower back, elbow, lateral shoulder, elbow pit, knee, and back of the knee) in a series of thermal images from 37 healthy participants. Results of the average temperature varied between 31.35 (knee for women) and 33.92 (lateral shoulder for men) in °C and TIs were lower than 2 and the results in the knee region are consistent with those reported in previous studies due to only the TI in the knee is known. This study contributes to the literature with reference values for nine trigger points other than the knee. This app is easy to use and may be useful in future applications for disease detection or monitoring of its progression.

In vivo brain temperature mapping using polymer optical fiber Bragg grating sensors

Variation of the brain temperature is strongly affected by blood flow, oxygen supply, and neural cell metabolism. Localized monitoring of the brain temperature is one of the most effective ways to correlate brain functions and diseases such as stroke, epilepsy, and mood disorders. While polymer optical fibers (POFs) are considered ideal candidates for temperature sensing in the brain, they have never been used so far in vivo. Here, we developed for the first, to the best of our knowledge, time an implantable probe based on a microstructured polymer optical fiber Bragg grating (FBG) sensor for intracranial brain temperature mapping. The temperature at different depths of the brain (starting from the cerebral cortex) and the correlation between the brain and body core temperature of a rat were recorded with a sensitivity of 33 pm/°C and accuracy <0.2°C. Our in vivo experimental results suggest that the proposed device can achieve real-time and high-resolution local temperature measurement in the brain, as well as being integrated with existing neural interfaces.

Buruli ulcer: application of thermography for remote diagnosis of a neglected tropical disease

We here report a proof of concept of using thermography for teledermatology practice for skin of colour using an example of an early case of Buruli ulcer – a neglected tropical disease that mainly affects people living in remote communities of Africa. In the presented case, the full extent of the lesion and lymphangitis were further and more precisely detected by thermography than even with the naked eye. Redness, an important sign of inflammation, can be masked in individuals with skin of colour. If thermal images can be transmitted to remote dermatologists in addition to regular photographs in the practice of teledermatology, this may improve diagnostic and prognostic accuracy, especially for this neglected population.

Can infrared thermography serve as an alternative to assess cumulative fatigue in women?

Muscle fatigue can limit performance both in sports and daily life activities. Consecutive days of exercise without a proper recovery time may elicit cumulative fatigue. Although it has been speculated that skin temperature could serve as an indirect indicator of exercise-induced adaptations, it is unclear if skin temperature measured by infrared thermography (IRT) could be an outcome related to the effects of cumulative fatigue. In this study, we recruited 21 untrained women and induced cumulative fatigue in biceps brachii over two consecutive days of exercise. We measured delayed onset muscle soreness (DOMS, using a numeric rate scale), maximal strength (using a dynamometer), and skin temperature (using IRT) in exercise and non-exercise muscles. Cumulative fatigue reduced muscle strength and increased DOMS. Skin temperature in the arm submitted to cumulative fatigue was higher for minimum and mean temperature, being asymmetrical in relation to the control arm. We also observed that the variations in the minimum and mean temperatures correlated with the strength losses. In summary, skin temperature measured by IRT seems promising to help detect cumulative fatigue in untrained women, being useful to explain strength losses. Future studies should provide additional evidence for the potential applications not only in trained participants but also in patients that may not be able to report outcomes of scales or precisely report DOMS.

Classic Versus Scarpa-sparing abdominoplasty: An infrared thermographic comparative analysis

BACKGROUND

Scarpa fascia preservation during abdominoplasty has been shown to have several clinical advantages. The mechanisms behind its efficiency have been the subject of several studies. Three theories have been proposed, relating to mechanical factors, lymphatic preservation, and improved vascularization. This study aimed to further investigate the possible vascular impact of Scarpa fascia preservation by using a thermographic analysis.

METHODS

A single-center prospective study was conducted, involving 12 female patients randomly and equally assigned to one of two surgical procedures: classic (Group A) and Scarpa-sparing abdominoplasty (Group B). Dynamic thermography was applied before and after surgery (one and six months), and two regions of interest (ROIs) were considered. The latter had the same location on every sample, and corresponded to areas where different surgical planes had been used. Static thermography was applied intraoperatively, and four ROIs were considered, located over Scarpa and over the deep fascia. The respective thermal data were analyzed.

RESULTS

The general characteristics of both groups were identical. Preoperative thermography demonstrated no differences between groups. Intraoperative higher thermal gradients between lateral and medial ROIs were observed in Group B (P = 0.037, right side). Dynamic thermography at one month demonstrated a trend for better thermal recovery and better thermal symmetry (P = 0.035, 1-min mark) in Group B. No other differences were found.

CONCLUSION

Dynamic thermography presented a better response when Scarpa fascia was preserved: stronger, faster, and more symmetric. Based on these results, improved vascularization may have a role in explaining the clinical efficiency of a Scarpa-sparing abdominoplasty.

Evaluation of the thermographic response of the lumbar region in dogs with bilateral hip osteoarthritis

Infrared thermography is suggested as a method of medical assistance for evaluating anatomical regions where there may be some inflammatory or painful condition that requires immediate medical attention. For this reason, this study aimed to characterize digital thermography of the lumbar region in police working dogs with hip osteoarthritis, 47 dogs with bilateral hip osteoarthritis were evaluated. A thermographic dorsoventral view of the dogs' backs were obtained, and mean and maximum temperatures were determined. In addition, results from the Canine Brief Pain Inventory, Liverpool Osteoarthritis in Dogs (LOAD), the Canine Orthopedic Index, and weight-bearing distribution evaluation were collected. Results were compared with an Independent Samples T-Test or ANOVA, followed by an LSD post hoc. Multiple regression was run to predict temperatures from age, sex, breed, body weight, and Orthopedic Foundation for Animals hip score and to predict clinical metrology scores and weight-bearing distribution results from temperature results. The sample included 28 males and 19 females, with a mean age of 6.3 ± 2.5 years and bodyweight of 26.9 ± 5.1 kg, with osteoarthritis hip scores of mild (70.2%), moderate (21.3%), and severe (8.5%). Significant differences were observed in mean temperatures between German Shepherd Dogs (GSD) and Labrador Retrievers (LR) (p < 0.01), and LR and Belgian Malinois (BM) (p=0.02). Mean temperature contributed to the prediction of LOAD and stiffness. LR showed significantly higher temperature values than GSD and BM. No differences were observed between osteoarthritis hip scores and mean temperature values contributed to LOAD scores' prediction. This relation needs to be addressed in further studies, involving a larger number of animals, and to determine changes in response to treatment.

Assessment of heat production and methane emission using infrared thermography in lactating Holstein and Gyrolando-F1 (½ Holstein ½ Gyr) crossbreed cows

Infrared thermography (IRT) is a non-invasive and efficient tool to detect changes in the animal's body surface temperature, which is directly associated with the animal's energy loss. Methane emission represents a significant energy loss, particularly in ruminants, as well as heat production. Therefore, the aim of this study was to correlate skin temperature measured using IRT with heat production (HP) and methane emission in lactating Holstein and crossbred ½ Holstein x ½ Gyr (Gyrolando-F1) cows. Six Gyrolando-F1 and four Holstein cows, all primiparous, at mid lactation were used to evaluate daily HP and methane emission using indirect calorimetry in respiratory chambers. Thermographic images were taken at anus, vulva, ribs (on the right side), left flank, right flank, right front foot, upper lip, masseter and eye; IRT was performed every hour during 8 h after the morning feeding. Cows received the same diet ad libitum. Daily methane emission was positively correlated with IRT taken at the right front foot 1 h after feeding in Gyrolando-F1 cows (r = 0.85, P < 0.05) and with IRT taken at the eye 5 h after feeding in Holstein cows (r = 0.88, P < 0.05). HP was positively correlated with IRT taken at the eye 6 h after feeding in Gyrolando-F1 cows (r = 0.85, P < 0.05) and with IRT taken at the eye 5 h after feeding in Holstein cows (r = 0.90, P < 0.05). Infrared thermography was positively correlated with HP and methane emission in both Holstein and Gyrolando-F1 lactating cows, although the anatomical points and times of image acquisition yielding the greatest correlation coefficients varies among breeds.

Minimally Invasive Live Tissue High-Fidelity Thermophysical Modeling Using Real-Time Thermography

We present a novel thermodynamic parameter estimation framework for energy-based surgery on live tissue, with direct applications to tissue characterization during electrosurgery. This framework addresses the problem of estimating tissue-specific thermodynamics in real-time, which would enable accurate prediction of thermal damage impact to the tissue and damage-conscious planning of electrosurgical procedures. Our approach provides basic thermodynamic information such as thermal diffusivity, and also allows for obtaining the thermal relaxation time and a model of the heat source, yielding in real-time a controlled hyperbolic thermodynamics model. The latter accounts for the finite thermal propagation time necessary for modeling of the electrosurgical action, in which the probe motion speed often surpasses the speed of thermal propagation in the tissue operated on. Our approach relies solely on thermographer feedback and a knowledge of the power level and position of the electrosurgical pencil, imposing only very minor adjustments to normal electrosurgery to obtain a high-fidelity model of the tissue-probe interaction. Our method is minimally invasive and can be performed in situ. We apply our method first to simulated data based on porcine muscle tissue to verify its accuracy and then to in vivo liver tissue, and compare the results with those from the literature. This comparison shows that parameterizing the Maxwell-Cattaneo model through the framework proposed yields a noticeably higher fidelity real-time adaptable representation of the thermodynamic tissue response to the electrosurgical impact than currently available. A discussion on the differences between the live and the dead tissue thermodynamics is also provided.

Spectral analysis of laser speckle contrast imaging and infrared thermography to assess skin microvascular reactive hyperemia

BACKGROUND

Post-occlusive reactive hyperemia (PORH) test with signal spectral analysis coupled provides potential indicators for the assessment of microvascular functions.

OBJECTIVE

The objective of this study is to investigate the variations of skin blood flow and temperature spectra in the PORH test. Furthermore, to quantify the oscillation amplitude response to occlusion within different frequency ranges.

MATERIALS AND METHODS

Ten healthy volunteers participated in the PORH test and their hand skin temperature and blood flow images were captured by infrared thermography (IRT) and laser speckle contrast imaging (LSCI) system, respectively. Extracted signals from selected areas were then transformed into the time-frequency space by continuous wavelet transform for cross-correlation analysis and oscillation amplitude response comparisons.

RESULTS

The LSCI and IRT signals extracted from fingertips showed stronger hyperemia response and larger oscillation amplitude compared with other areas, and their spectral cross-correlations decreased with frequency. According to statistical analysis, their oscillation amplitudes in the PORH stage were obviously larger than the baseline stage within endothelial, neurogenic, and myogenic frequency ranges (p < 0.05), and their quantitative indicators of oscillation amplitude response had high linear correlations within endothelial and neurogenic frequency ranges.

CONCLUSION

Comparisons of IRT and LSCI techniques in recording the reaction to the PORH test were made in both temporal and spectral domains. The larger oscillation amplitudes suggested enhanced endothelial, neurogenic, and myogenic activities in the PORH test. We hope this study is also significant for investigations of response to the PORH test by other non-invasive techniques.

Clinical assessment of patients with systemic sclerosis: is there a place for thermography?

Recurrent changes of temperature and persistence of cooling along fingers at the room temperature make hands the most frequent region of interest for thermography in systemic sclerosis (SSc). The aim of this study was to evaluate dependance of temperature in hands on a subtype of the disease, immune profile of antinuclear antibodies (ANA), and lung involvement. There were 29 patients with limited cutaneous involvement (lcSSc) and 10 patients with diffuse cutaneous disease (dcSSc) enrolled for the study. To compare measurements to normal values, there were enrolled 29 healthy volunteers (control group). All participants were submitted to thermography with handheld camera FLIR One Pro for iOS, attached to mobile phone iPhone 11, at the fixed temperature of 21 °C. Measurements included average temperature (T_avg) over nailfolds in thumbs and fingers II-V, as well as the difference in average temperatures (TΔ) between metacarpus of the hand and its thumb and fingers II-V. Both thumbs and fingers II-V remained cooler in subjects with dcSSc compared to those with lcSSc. This implicated a significantly greater TΔ along thumbs and fingers II-V in dcSSc group. Although T_avg at nailfolds in SSc patients was not lower than in healthy controls, TΔ remained significantly more pronounced in both lcSSc and dcSSc subjects. A positivity to ACA in lcSSc group was found to be associated with significantly lower T_avg and more pronounced TΔ in fingers II-V than the presence of anti-Scl70 antibodies. Temperature measurements remained statistically independent on a presence of ILD in lcSSc group, but both thumbs and fingers II-V in dcSSc group were warmer in case of lung involvement. The study showed the dcSSc subtype, the positivity of ACA in lcSSc, but not lung involvement were associated with poorer thermal control in the hands of SSc patients. A comparison to healthy controls highlighted the weakness of temperature measurements at nailfolds (T_avg) but increased the value of TΔ in thermography of hands.

Can Adipose Tissue Influence the Evaluation of Thermographic Images in Adolescents?

Infrared thermography (IRT) is a technology easy to use for clinical purposes as a pre-diagnostic tool for many health conditions. However, the analysis process of a thermographic image needs to be meticulous to make an appropriate decision. The adipose tissue is considered a potential influence factor in the skin temperature (Tsk) values obtained by IRT. This study aimed to verify the influence of body fat percentage (%BF) on Tsk measured by IRT in male adolescents. A total of 100 adolescents (16.79 ± 0.97 years old and body mass index of 18.41 ± 2.32 kg/m²) was divided into two groups through the results of a dual-energy X-ray absorptiometry analysis: obese (n = 50, %BF 30.21 ± 3.79) and non-obese (n = 50, %BF 11.33 ± 3.08). Thermograms were obtained by a FLIR T420 infrared camera and analyzed by ThermoHuman^® software version 2.12, subdividing the body into seven regions of interest (ROI). The results showed that obese adolescents presented lower mean Tsk values than the non-obese for all ROIs (p < 0.05), with emphasis on the global Tsk (0.91 °C) and anterior (1.28 °C) and posterior trunk (1.18 °C), with "very large" effect size values. A negative correlation was observed in all the ROI (p < 0.01), mainly in the anterior (r = -0.71, p < 0.001) and posterior trunk (r = -0.65, p < 0.001). Tables of thermal normality were proposed for different ROIs according to the classification of obesity. In conclusion, the %BF affects the registered Tsk values in male Brazilian adolescents assessed by IRT.

CFPNet-M: A light-weight encoder-decoder based network for multimodal biomedical image real-time segmentation

-Deep learning techniques are proving instrumental in identifying, classifying, and quantifying patterns in medical images. Segmentation is one of the important applications in medical image analysis. The U-Net has become the predominant deep-learning approach to medical image segmentation tasks. Existing U-Net based models have limitations in several respects, however, including: the requirement for millions of parameters in the U-Net, which consumes considerable computational resources and memory; the lack of global information; and incomplete segmentation in difficult cases. To remove some of those limitations, we built on our previous work and applied two modifications to improve the U-Net model: 1) we designed and added the dilated channel-wise CNN module and 2) we simplified the U-shape network. We then proposed a novel light-weight architecture, the Channel-wise Feature Pyramid Network for Medicine (CFPNet-M). To evaluate our method, we selected five datasets from different imaging modalities: thermography, electron microscopy, endoscopy, dermoscopy, and digital retinal images. We compared its performance with several models having a variety of complexities. We used the Tanimoto similarity instead of the Jaccard index for gray-level image comparisons. The CFPNet-M achieves segmentation results on all five medical datasets that are comparable to existing methods, yet require only 8.8 MB memory, and just 0.65 million parameters, which is about 2% of U-Net. Unlike other deep-learning segmentation methods, this new approach is suitable for real-time application: its inference speed can reach 80 frames per second when implemented on a single RTX 2070Ti GPU with an input image size of 256 × 192 pixels.

Infrared Thermography, Intratendon Vascular Resistance, and Echotexture in Athletes with Patellar Tendinopathy: A Cross-Sectional Study

Ultrasonographic signs of tendinopathies are an increase in thickness, loss of alignment in collagen fibers and the presence of neovascularization. Nevertheless, analysis of intratendinous vascular resistance (IVR) can be more useful for understanding the physiological state of the tissue. To show thermal, echotextural, and Doppler signal differences in athletes with patellar tendinopathy and controls. Twenty-six athletes with patellar tendinopathy (PT) participants (30.1 years; SD = 9.0 years) and 27 asymptomatic athletes (23.3 years; SD = 5.38 years) were evaluated with thermographic and Doppler ultrasonography (DS). Area of Doppler signals (DS), echotextural parameters (echointensity and echovariation) and IVR were determined by image analysis. The statistical analysis was performed by Bayesian methods and the results were showed by Bayes Factor (BF10: probability of alternative hypothesis over null hypothesis), and Credibility intervals (CrI) of the effect. The absolute differences of temperature (TD) were clearly greater (BF10 = 19) in the tendinopathy group (patients) than in controls. Regarding temperature differences between the affected and healthy limb, strong evidence was found (BF₁₀ = 14) for a higher temperature (effect = 0.53°C; 95% CrI = 0.15°C-0.95°C) and very strong for reduced IVR compared (BF₁₀ = 71) (effect = -0.67; 95% CrI = -1.10 to 0.25). The differences in area of DS (BF₁₀ = 266) and EV (BF₁₀ = 266) were higher in tendinopathy group. TD showed a moderate positive correlation with VISA-P scores (tau-B = .29; 95% CrI = .04-.51) and strong correlation with IVR (r = -.553; 95%CrI = -.75 to .18). Athletes with patellar tendinopathy showed a more pronounced thermal difference, a larger area of Doppler signal, a lower IVR and a moderately higher echovariaton than controls. The correlation between temperature changes and IVR might be related with the coexistence of degenerative and inflammatory process in PT.

Effect of Whole-, Upper-, and Lower-Body High-Intensity Rowing Exercise on Skin Temperature Measured by Thermography

Purpose: Despite the growing works analyzing exercise-induced thermoregulatory adjustments through thermography, the skin temperature (Tsk) response of the same muscle groups underwent to different exercise demands has not been investigated. This study analyzed the behavior of Tsk of the same muscle groups when exercised with different demands in rowing. Methods: Eighteen men underwent three performance tests on a rowing ergometer: whole-body 2,000 m test (RT_WB), upper-body (RT_UB), and lower-body (RT_LB) tests. In each condition, thermograms were recorded before (pre), immediately after test (post), and at 10 (REC₁₀), 20 (REC₂₀), and 30 (REC₃₀) minutes post-exercise recovery. Tsk was measured at the pectoral (control body region), upper back, quadriceps, brachial biceps, and forearm. Results: Pectoral-Tsk reduced comparably in response to all testing conditions (p < .05). Upper back-Tsk decreased post (p < .001) and returned to baseline in the RT_UB (REC₁₀, p = 1.0) and RT_WB (REC₃₀, p = .128), while remained reduced in the RT_LB (p < .001). Quadriceps-Tsk reduced post (p < .05) and returned to baseline in the RT_WB and RT_LB at REC₁₀ (p = 1.0), remaining reduced in the RT_UB during recovery (p < .05). Regarding the upper limbs, Tsk increased more markedly in the RT_UB versus RT_WB during the recovery period (p < .05); in the RT_LB, biceps-Tsk remained below baseline over time (p < .05), whereas the forearm-Tsk was restored at REC₁₀ (p = 1.0). Conclusion: Manipulating the muscle groups involved in rowing alters the Tsk response within equal ROI. Exercise-induced Tsk changes can reflect local hemodynamic and thermoregulatory adjustments.

Temperature mapping of non-photochemical quenching in Chlorella vulgaris

Light intensity and temperature independently impact all parts of the photosynthetic machinery in plants and algae. Yet to date, the vast majority of pulse amplitude modulated (PAM) chlorophyll a fluorescence measurements have been performed at well-defined light intensities, but rarely at well-defined temperatures. In this work, we show that PAM measurements performed at various temperatures produce vastly different results in the chlorophyte Chlorella vulgaris. Using a recently developed Phenoplate technique to map quantum yield of Photosystem II (Y(II)) and non-photochemical quenching (NPQ) as a function of temperature, we show that the fast-relaxing NPQ follows an inverse normal distribution with respect to temperature and appears insensitive to previous temperature acclimation. The slow-relaxing or residual NPQ after 5 minutes of dark recovery follows a normal distribution similar to Y(II) but with a peak in the higher temperature range. Surprisingly, higher slow- and fast-relaxing NPQ values were observed in high-light relative to low-light acclimated cultures. Y(II) values peaked at the adaptation temperature regardless of temperature or light acclimation. Our novel findings show the complete temperature working spectrum of Y(II) and how excess energy quenching is managed across a wide range of temperatures in the model microalgal species C. vulgaris. Finally, we draw attention to the fact that the effect of the temperature component in PAM measurements has been wildly underestimated, and results from experiments at room temperature can be misleading.

Relationship between Repeated Sprint Ability, Countermovement Jump and Thermography in Elite Football Players

Football is a very demanding sport which requires players to exert maximum effort, producing fatigue and eventually injuries. Thermography can be used to detect fatigue and prevent its consequences through thermal asymmetries in the bilateral body areas; however, its adequacy for elite footballers has not been widely studied. Therefore, the objective of the present investigation was to determine the suitability of thermography to detect fatigue in male football players. For this reason, twenty participants were gathered into a pair of subgroups (low [<0.2 °C] vs. high thermal asymmetry [≥0.2 °C]) based on a thermography session of the lower limbs (thighs, calves, and hamstrings). After the thermography session, players performed CMJs before and after an RSA test (6 × 30 m/20″). A mixed two-way analysis of variance and Bonferroni post hoc pairwise comparisons were undertaken to analyse the results. No significant differences (p > 0.05) were found in any of the RSA test variables between low and high thermal asymmetry groups for thighs and calves. On the other hand, the low thermal asymmetry hamstring group reported a smaller percentage difference in sprints for the first sprint (%Diff) and a larger percentage difference in sprints two and three with respect to the best sprint (%Best). For CMJs, the low thermal asymmetry hamstring group reported significantly higher values post-RSA test, indicating better performance. Accordingly, thermography can provide information about performance in CMJ and RSA tests through hamstring asymmetries over 0.2 °C. Meanwhile, larger asymmetries than 0.2 °C in calves and thighs do not seem to be related to performance in these tests; therefore, coaches should consider if it is optimal to align players with high hamstring asymmetries.

Prediction of rectal temperature in Holstein heifers using infrared thermography, respiration frequency, and climatic variables

The objective of this study was to develop an equation to predict rectal temperature (RT) using body surface temperatures (BSTs), physiological and climatic variables in pubertal Holstein heifers in an arid region. Two hundred Holstein heifers were used from July to September during two consecutive summers (2019 and 2020). Respiratory frequency (RF) was used as a physiological variable and ambient temperature, relative humidity and temperature-humidity index as climatic variables. For the body surface temperatures, infrared thermography was used considering the following anatomical regions: shoulder, belly, rump, leg, neck, head, forehead, nose, loin, leg, vulva, eye, flank, and lateral area (right side). Initially, a Pearson correlation analysis examined the relationship among variables, and then multiple linear regression analysis was used to develop the prediction equation. Physiological parameters RT and RF were highly correlated with each other (r = 0.73; P˂0.0001), while all BST presented from low to moderate correlations with RT and RF. BST forehead temperature (FH) showed the highest (r = 0.58) correlation with RT. The equation RT = 35.55 + 0.033 (RF) + 0.030 (FH) + e_i is considered the best regression equation model to predict RT in Holstein heifers in arid zones. This decision was made on the indicators R² = 60%, RMSE = 0.25, and AIC = 0.25, which were considered adequate variability indicators.

A Lanthanide Upconversion Nanothermometer for Precise Temperature Mapping on Immune Cell Membrane

Cell temperature monitoring is of great importance to uncover temperature-dependent intracellular events and regulate cellular functions. However, it remains a great challenge to precisely probe the localized temperature status in living cells. Herein, we report a strategy for in situ temperature mapping on an immune cell membrane for the first time, which was achieved by using the lanthanide-doped upconversion nanoparticles. The nanothermometer was designed to label the cell membrane by combining metabolic labeling and click chemistry and can leverage ratiometric upconversion luminescence signals to in situ sensitively monitor temperature variation (1.4% K^-1). Moreover, a purpose-built upconversion hyperspectral microscope was utilized to synchronously map temperature changes on T cell membrane and visualize intracellular Ca²⁺ influx. This strategy was able to identify a suitable temperature status for facilitating thermally stimulated calcium influx in T cells, thus enabling high-efficiency activation of immune cells. Such findings might advance understandings on thermally dependent biological processes and their regulation methodology.

Thermographic Imaging in Cultural Heritage: A Short Review

Over the recent period, there has been an increasing interest in the use of pulsed infrared thermography (PT) for the non-destructive evaluation of Cultural Heritage (CH). Unlike other techniques that are commonly employed in the same field, PT enables the depth-resolved detection of different kinds of subsurface features, thus providing helpful information for both scholars and restorers. Due to this reason, several research activities are currently underway to further improve the PT effectiveness. In this manuscript, the specific use of PT for the analysis of three different types of CH, namely documentary materials, panel paintings-marquetery, and mosaics, will be reviewed. In the latter case, i.e., mosaics, passive thermography combined with ground penetrating radar (GPR) and digital microscopy (DM) have also been deepened, considering their suitability in the open field. Such items have been selected because they are characterized by quite distinct physical and structural properties and, therefore, different PT (and, in some cases, verification) approaches have been employed for their investigations.

Automated Impact Damage Detection Technique for Composites Based on Thermographic Image Processing and Machine Learning Classification

Composite materials are one of the primary structural components in most current transportation applications, such as the aerospace industry. Composite material diagnostics is a promising area in the fight against structural damage in aircraft and spaceships. Detection and diagnostic technologies often provide analysts with a valuable and rapid mechanism to monitor the health and safety of composite materials. Although many attempts have been made to develop damage detection techniques and make operations more efficient, there is still a need to develop/improve existing methods. Pulsed thermography (PT) technology was used in this study to obtain healthy and defective data sets from custom-designed composite samples having similar dimensions but different thicknesses (1.6 and 3.8). Ten carbon fibre-reinforced plastic (CFRP) panels were tested. The samples were subjected to impact damage of various energy levels, ranging from 4 to 12 J. Two different methods have been applied to detect and classify the damage to the composite structures. The first applied method is the statistical analysis, where seven different statistical criteria have been calculated. The final results have proved the possibility of detecting the damaged area in most cases. However, for a more accurate detection technique, a machine learning method was applied to thermal images; specifically, the Cube Support Vector Machine (SVM) algorithm was selected. The prediction accuracy of the proposed classification models was calculated within a confusion matrix based on the dataset patterns representing the healthy and defective areas. The classification results ranged from 78.7% to 93.5%, and these promising results are paving the way to develop an automated model to efficiently evaluate the damage to composite materials based on the non-distractive testing (NDT) technique.

Chronic and Acute Effects on Skin Temperature from a Sport Consisting of Repetitive Impacts from Hitting a Ball with the Hands

Valencian handball consists in hitting the ball with the hands and it may contribute to injury development on the hands. This study aimed to analyze skin temperature asymmetries and recovery after a cold stress test (CST) in professional players of Valencian handball before and after a competition. Thirteen professional athletes and a control group of ten physically active participants were measured. For both groups, infrared images were taken at the baseline condition; later they underwent a thermal stress test (pressing for 2 min with the palm of the hand on a metal plate) and then recovery images were taken. In athletes, the images were also taken after their competition. Athletes at baseline condition presented lower temperatures (p < 0.05) in the dominant hand compared with the non-dominant hand. There were asymmetries in all regions after their match (p < 0.05). After CST, a higher recovery rate was found after the game. The regions with the most significant differences in variation, asymmetries and recovery patterns were the index, middle and ring fingers, and the palm of the dominant hand. Taking into account that lower temperatures and the absence of temperature variation may be the consequence of a vascular adaptation, thermography could be used as a method to prevent injuries in athletes from Valencian handball.

Integrating weather observations and local-climate-zone-based landscape patterns for regional hourly air temperature mapping using machine learning

Air temperature is a crucial variable of urban meteorology and is essential to many urban environments, urban climate and climate-change-related studies. However, due to the limited observational records of air temperature and the complex urban morphology and environment, it might not be easy to map the hourly air temperature with a fine resolution at the surface level within and around cities via conventional methods. Thus, this study employed machine learning (ML) algorithms and meteorological and landscape data to develop hourly air temperature mapping techniques and methods at the 1-km resolution over a multi-year warm seasons period. Guangdong Province, China was selected for the case study. Random forest algorithm was employed for the hourly air temperature mapping. The validation results showed that the hourly air temperature maps exhibit good accuracy from 2008 to 2019, with mean R², root mean square error (RMSE) and mean absolute error (MAE) values of 0.8001, 1.4821 °C and 1.0872 °C, respectively. The importance assessment of the driving factors showed that meteorological factors, especially relative humidity, contributed the most to the air temperature mapping. Simultaneously, landscape factors also played a non-negligible role. Further analysis revealed that the maps steadily maintained high accuracy at nighttime (20:00-7:00), which is essential for investigating nighttime urban climate conditions, especially the urban heat island effect. Moreover, a correlation existed between the nighttime air temperature changes and urban morphology represented by the local climate zones. Air temperatures tended to fall more slowly in the core of metropolitan areas than in the urban fringe. Using ML, this study reliably improves the spatial refinement of hourly air temperature mapping and reveals the spatially explicit air temperature patterns in and around cities at different times in a day during the warm seasons. Moreover, it provides a novel valuable and reliable dataset for air-temperature-related implementation and studies.

Isolates from Mango Fruits

Colletotrichum causing anthracnose in mango is known for its variable virulence that may have an effect on disease development and efficacy of management strategies. In this study, we characterized Colletotrichum spp. isolated from mango fruits under in vitro and in vivo conditions using close-range thermography and reflectance spectroscopy. Twenty-six isolates were phylogenetically characterized to ascertain species using the internal transcribed spacer sequence. Virulence, spectral (in vivo and in vitro), and thermographic responses (in vivo) of these isolates were analyzed. Isolates were grouped into the Colletotrichum gloeosporioides species complex and classified into eight morphotypes. Mycelial growth, conidia production, sporulation abundance, and area under disease progress curve (AUDPC) varied largely among isolates. Disease symptoms were observed 4 days after inoculation (dai), and, for most morphotypes, changes in tissue temperature were registered at 11 dai, with the greatest decrease at 14 dai with pathogen sporulation. In vitro and in vivo morphotypes shared changes in the spectrum range, and main variations were found in the number of informative spectral bands. In vivo average gross reflectance was higher in disease-inoculated tissue than in healthy uninoculated tissue. Morphotype responses varied depending on AUDPC values and postinoculation time. Discriminant analysis of the spectral response using principal component analysis and partial least squares regression explained 94 to 96.3 and 98 to 99.9% of the variance from in vitro and in vivo tests, respectively. Spectral markers were obtained for four distinct morphotype groups. We found three (550 to 650, 650.1 to 790, and 1,300 to 1,400 nm) and two (520 to 830 and 1,100 to 1,450 nm) regions with highly (P < 0.05) discriminant spectral bands for diseased fruits and morphotype characterization.

[Application of infrared thermography technique to assist peroneal artery perforator flap in the repair of oral and maxillofacial defects]

Objective

To explore the application value of infrared thermography (IRT) technique assisted peroneal artery perforator flap in repairing oral and maxillofacial defects.

Methods

The clinical data of 20 patients with oral and maxillofacial malignant tumors treated with peroneal artery perforator flap between October 2020 and December 2021 were retrospectively analysed. There were 13 males and 7 females, with an average age of 56.5 years (range, 32-76 years). There were 8 cases of tongue cancer, 5 cases of parotid gland cancer, 4 cases of buccal cancer, and 3 cases of mandibular gingival cancer; and 12 cases of squamous cell carcinoma, 3 cases of adenoid cystic carcinoma, and 5 cases of mucoepidermoid carcinoma. Color Doppler ultrasound (CDU) and IRT technique were performed before operation to locate the peroneal artery perforator and assist in the design of the flap. The sensitivity, specificity, positive predictive value, and negative predictive value of CDU and IRT technique were compared with the actual exploration during operation. The accuracy of CDU and IRT technique in detecting the number of peroneal artery perforator and the most viable perforating points was compared. The patients were followed up regularly to observe the recovery of donor and recipient sites, the occurrence of complications, and the recurrence and metastasis of tumors.

Results

The sensitivity, specificity, positive predictive value, and negative predictive value of peroneal artery perforators detected by IRT technique before operation were 72.22%, 50.00%, 92.86%, and 16.67% respectively, which were higher than those by CDU (64.17%, 33.33%, 84.62%, and 14.29% respectively). Forty-five peroneal artery perforators were found by CDU before operation, and 35 were confirmed during operation, with an accuracy rate of 77.8%; 43 "hot spots" were found by IRT technique, and 32 peroneal artery perforators were confirmed within the "hot spots" range during operation, with an accuracy rate of 74.4%; there was no significant difference between the two methods ( χ²=0.096, P=0.757). The accuracy rates of the most viable perforating points found by CDU and IRT technique were 80.95% (17/21) and 94.74% (18/19), respectively, and there was no significant difference between them ( χ²=0.115, P=0.734). The localization errors of CDU and IRT technique were (5.12±2.10) and (4.23±1.87) mm, respectively, and there was no significant difference between them ( t=1.416, P=0.165). All the perforator flaps survived, and the incisions of donor and recipient sites healed by first intention. All patients were followed up 5-18 months, with an average of 11 months. The skin flap was soft and had good blood supply, and the lower limb scar was concealed and the lower limb had good function. No lower limb swelling, pain, numbness, ankle instability, or other complications occurred, and no tumor recurrence and metastasis were found during the follow-up.

Conclusion

Compared with the CDU, using the IRT technique to assist the preoperative peroneal artery perforator flap design to repair the oral and maxillofacial defects has a high clinical application value.

Application of the Two-Dimensional Entropy Measures in the Infrared Thermography-Based Detection of Rider: Horse Bodyweight Ratio in Horseback Riding

As obesity is a serious problem in the human population, overloading of the horse's thoracolumbar region often affects sport and school horses. The advances in using infrared thermography (IRT) to assess the horse's back overload will shortly integrate the IRT-based rider-horse fit into everyday equine practice. This study aimed to evaluate the applicability of entropy measures to select the most informative measures and color components, and the accuracy of rider:horse bodyweight ratio detection. Twelve horses were ridden by each of the six riders assigned to the light, moderate, and heavy groups. Thermal images were taken pre- and post-exercise. For each thermal image, two-dimensional sample (SampEn), fuzzy (FuzzEn), permutation (PermEn), dispersion (DispEn), and distribution (DistEn) entropies were measured in the withers and the thoracic spine areas. Among 40 returned measures, 30 entropy measures were exercise-dependent, whereas 8 entropy measures were bodyweight ratio-dependent. Moreover, three entropy measures demonstrated similarities to entropy-related gray level co-occurrence matrix (GLCM) texture features, confirming the higher irregularity and complexity of thermal image texture when horses worked under heavy riders. An application of DispEn to red color components enables identification of the light and heavy rider groups with higher accuracy than the previously used entropy-related GLCM texture features.

Prospective Study of the Detection of Bacterial Pathogens in Pediatric Clinical Specimens Using the Melting Temperature Mapping Method

The melting temperature (Tm) mapping method is a novel technique that uses seven primer sets without sequencing to detect dominant bacteria. This method can identify pathogenic bacteria in adults within 3 h of blood collection without using conventional culture methods. However, no studies have examined whether pathogenic bacteria can be detected in clinical specimens from pediatric patients with bacterial infections. Here, we designed a new primer set for commercial use, constructed a database with more bacterial species, and examined the agreement rate of bacterial species in vitro. Moreover, we investigated whether our system could detect pathogenic bacteria from pediatric patients using the Tm mapping method and compared the detection rates of the Tm mapping and culture methods. A total of 256 pediatric clinical specimens from 156 patients (94 males and 62 females; median age, 2 years [<18 years of age]) were used. The observed concordance rates between the Tm mapping method and the culture method for both positive and negative samples were 76.4% (126/165) in blood samples and 79.1% (72/91) in other clinical specimens. The Tm mapping detection rate was higher than that of culture using both blood and other clinical specimens. In addition, using the Tm mapping method, we identified causative bacteria in pediatric clinical specimens quicker than when using blood cultures. Hence, the Tm mapping method could be a useful adjunct for diagnosing bacterial infections in pediatric patients and may be valuable in antimicrobial stewardship for patients with bacterial infections, especially in culture-negative cases. IMPORTANCE This study provides novel insights regarding the use of the melting temperature (Tm) mapping method to identify the dominant bacteria in samples collected from pediatric patients. We designed a new set of primers for commercial use and developed a database of different bacteria that can be identified using these primers. We show that the Tm mapping method could identify bacteria from blood samples and other clinical specimens. Moreover, we provide evidence that the Tm mapping method has a higher detection rate than that of the culture-based methods and can achieve a relatively high agreement rate. We believe that our study makes a significant contribution to this field because rapid identification of the source of bacterial infections can drastically improve patient outcomes and impede the development of antibiotic-resistant bacteria.

Towards Exercise Radiomics: Deep Neural Network-Based Automatic Analysis of Thermal Images Captured During Exercise

Infrared thermography is increasingly applied in sports science due to promising observations regarding changes in skin's surface radiation temperature ( T_sr) before, during, and after exercise. The common manual thermogram analysis limits an objective and reproducible measurement of T_sr. Previous analysis approaches depend highly on expert knowledge and have not been applied during movement. We aimed to develop a deep neural network (DNN) capable of automatically and objectively segmenting body parts, recognizing blood vessel-associated T_sr distributions, and continuously measuring T_sr during exercise. We conducted 38 cardiopulmonary exercise tests on a treadmill. We developed two DNNs: body part network and vessel network, to perform semantic segmentation of 1 107 855 captured thermal images. Both DNNs were trained with 263 training and 75 validation images. Additionally, we compare the results of a common manual thermogram analysis with these of the DNNs. Performance analysis identified a mean IoU of 0.8 for body part network and 0.6 for vessel network. There is a high agreement between manual and automatic analysis (r = 0.999; p 0.001; T-test: p = 0.116), with a mean difference of 0.01 ^C (0.08). Non-parametric Bland Altman's analysis showed that the 95% agreement ranges between -0.086 ^C and 0.228 ^C. The developed DNNs enable automatic, objective, and continuous measurement of T_sr and recognition of blood vessel-associated T_sr distributions in resting and moving legs. Hence, the DNNs surpass previous algorithms by eliminating manual region of interest selection and form the currently needed foundation to extensively investigate T_sr distributions related to non-invasive diagnostics of (patho-)physiological traits in means of exercise radiomics.

Seamless Navigation, 3D Reconstruction, Thermographic and Semantic Mapping for Building Inspection

We present a workflow for seamless real-time navigation and 3D thermal mapping in combined indoor and outdoor environments in a global reference frame. The automated workflow and partly real-time capabilities are of special interest for inspection tasks and also for other time-critical applications. We use a hand-held integrated positioning system (IPS), which is a real-time capable visual-aided inertial navigation technology, and augment it with an additional passive thermal infrared camera and global referencing capabilities. The global reference is realized through surveyed optical markers (AprilTags). Due to the sensor data’s fusion of the stereo camera and the thermal images, the resulting georeferenced 3D point cloud is enriched with thermal intensity values. A challenging calibration approach is used to geometrically calibrate and pixel-co-register the trifocal camera system. By fusing the terrestrial dataset with additional geographic information from an unmanned aerial vehicle, we gain a complete building hull point cloud and automatically reconstruct a semantic 3D model. A single-family house with surroundings in the village of Morschenich near the city of Jülich (German federal state North Rhine-Westphalia) was used as a test site to demonstrate our workflow. The presented work is a step towards automated building information modeling.

Development, Validation and Preliminary Experiments of a Measuring Technique for Eggs Aging Estimation Based on Pulse Phase Thermography

Assessment of the freshness of hen eggs destinated to human consumption is an extremely important goal for the modern food industry and sale chains, as eggs show a rapid natural aging which also depends on the storage conditions. Traditional techniques, such as candling and visual observation, have some practical limitations related to the subjective and qualitative nature of the analysis. The main objective of this paper is to propose a robust and automated approach, based on the use of pulsed phase thermography (PPT) and image processing, that can be used as an effective quality control tool to evaluate the freshness of eggs. As many studies show that the air chamber size is proportional to the egg freshness, the technique relies on the monitoring of the air chamber parameters to infer egg aging over time. The raw and phase infrared images are acquired and then post-processed by a dedicated algorithm which has been designed to automatically measure the size of the air chamber, in terms of normalized area and volume. The robustness of the method is firstly assessed through repeatability and reproducibility tests, which demonstrate that the uncertainty in the measure of the air chamber size never exceeds 5%. Then, an experimental campaign on a larger sample of 30 eggs, equally divided into three size categories (M, L, XL), is conducted. For each egg, the main sizes of the air chamber are measured with the proposed method and their evolution over time is investigated. Results have revealed, for all the egg categories, the existence of an analytic relationship and a high degree of correlation (R2 > 0.95) between the geometric data of the air chamber and the weight loss, which is a well-known marker of egg aging.