Accuracy of infrared thermography for perforator mapping: A systematic review and meta-analysis of diagnostic studies.

INTRODUCTION: Infrared thermography allows the detection of infrared radiation which can be reliably associated with skin temperature. Modern portable thermography devices have been used to identify the location of skin perforators by detecting subtle differences in skin temperature. The aim of this study is to conduct a diagnostic accuracy systematic review to determine the specificity and sensitivity of infrared thermography. MATERIALS AND METHODS: A PRISMA-compliant systematic review and meta-analysis was conducted, scrutinising PUBMED and EMBASE databases for diagnostic studies measuring the accuracy of infrared thermography for perforator identification. Article screening, review and data gathering was conducted in parallel by two independent authors. Eligible studies were subject to a formal risk of bias was assessment using the QUADAS2 instrument. RESULTS: A total of 254 entries were obtained, of which 7 satisfied our pre-established inclusion criteria. These studies reported a total of 435 perforators in 133 individuals. The most commonly investigated locations were the antero-lateral thigh and abdominal wall. Reported sensitivity values ranged from 73.7% to 100%. A meta-analysis demonstrated a cumulative sensitivity of 95%. Specificity was not routinely reported. All studies presented a moderate to high risk of bias according to QUADAS2. DISCUSSION: Affordable infrared thermography devices are an interesting alternative to traditional preoperative investigations for perforator mapping. They are sensitive enough to reliably identify a large proportion of perforators as "hot-spots". However, there is limited evidence to estimate the specificity of this technology, as studies have failed to report true negative values associated with "cold-spots".

Point-of-care infrared thermal imaging for differentiating venomous snakebites from non-venomous and dry bites.

BACKGROUND: Local envenomation following snakebites is accompanied by thermal changes, which could be visualized using infrared imaging. We explored whether infrared thermal imaging could be used to differentiate venomous snakebites from non-venomous and dry bites. METHODS: We prospectively enrolled adult patients with a history of snakebite in the past 24 hours presenting to the emergency of a teaching hospital in southern India. A standardized clinical evaluation for symptoms and signs of envenomation including 20-minute whole-blood clotting test and prothrombin time was performed to assess envenomation status. Infrared thermal imaging was done at enrolment, 6 hours, and 24 hours later using a smartphone-based device under ambient conditions. Processed infrared thermal images were independently interpreted twice by a reference rater and once by three novice raters. FINDINGS: We studied 89 patients; 60 (67%) of them were male. Median (IQR) time from bite to enrolment was 11 (6.5-15) hours; 21 (24%) patients were enrolled within 6 hours of snakebite. In all, 48 patients had local envenomation with/without systemic envenomation, and 35 patients were classified as non-venomous/dry bites. Envenomation status was unclear in six patients. At enrolment, area of increased temperature around the bite site (Hot spot) was evident on infrared thermal imaging in 45 of the 48 patients with envenomation, while hot spot was evident in only 6 of the 35 patients without envenomation. Presence of hot spot on baseline infrared thermal images had a sensitivity of 93.7% (95% CI 82.8% to 98.7%) and a specificity of 82.9% (66.3% to 93.4%) to differentiate envenomed patients from those without envenomation. Interrater agreement for identifying hot spots was more than substantial (Kappa statistic >0.85), and intrarater agreement was almost perfect (Kappa = 0.93). Paradoxical thermal changes were observed in 14 patients. CONCLUSIONS: Point-of-care infrared thermal imaging could be useful in the early identification of non-venomous and dry snakebites.

On the possibility of using temperature to aid in thyroid nodule investigation.

Thyroid nodules are common, and their investigation is very important to exclude the possibility of cancer. The increase in blood vessels of malignant tumours may be related to local temperature augmentation detectable on the skin surface. The objective of this paper is to evaluate the feasibility of Infrared Thermography for cancer identification. For this purpose, two studies were performed. One used numerical modelling to simulate regional metabolic temperature propagation to evaluate whether a nodule is perceptible on the skin surface. A second study considered thyroid nodule identification by using convolutional neural networks (CNNs). First, variations in nodular size and fat thickness were investigated, showing that the fat layer has an important role in regional heat transfer. In the second study, the training process achieved accuracy of 96% for in-sample and 95% for validation. In the testing phase, 92% accuracy, 100% precision and 80% recall were achieved. Thus, the presented studies suggest the feasibility of using Infrared Thermography with the CNN Artificial Intelligence technique as additional information in the investigation of thyroid nodules for patients without a very thick subcutaneous fat layer.

Temperature Screening for SARS-CoV-2 in Nursing Homes: Evidence from Two National Cohorts.

BACKGROUND/OBJECTIVES: Infection screening tools classically define fever as 38.0°C (100.4°F). Frail older adults may not mount the same febrile response to systemic infection as younger or healthier individuals. We evaluate temperature trends among nursing home (NH) residents undergoing diagnostic SARS-CoV-2 testing and describe the diagnostic accuracy of temperature measurements for predicting test-confirmed SARS-CoV-2 infection. DESIGN: Retrospective cohort study evaluating diagnostic accuracy of pre-SARS-CoV-2 testing temperature changes. SETTING: Two separate NH cohorts tested diagnostically (e.g., for symptoms) for SARS-CoV-2. PARTICIPANTS Veterans residing in Veterans Affairs (VA) managed NHs and residents in a private national chain of community NHs. MEASUREMENTS: For both cohorts, we determined the sensitivity, specificity, and Youden's index with different temperature cutoffs for SARS-CoV-2 polymerase chain reaction results. RESULTS: The VA cohort consisted of 1,301 residents in 134 facilities from March 1, 2020, to May 14, 2020, with 25% confirmed for SARS-CoV-2. The community cohort included 3,368 residents spread across 282 facilities from February 18, 2020, to June 9, 2020, and 42% were confirmed for SARS-CoV-2. The VA cohort was younger, less White, and mostly male. A temperature testing threshold of 37.2°C has better sensitivity for SARS-CoV-2, 76% and 34% in the VA and community NH, respectively, versus 38.0°C with 43% and 12% sensitivity, respectively. CONCLUSION: A definition of 38.0°C for fever in NH screening tools should be lowered to improve predictive accuracy for SARS-CoV-2 infection. Stakeholders should carefully consider the impact of adopting lower testing thresholds on testing availability, cost, and burden on staff and residents. Temperatures alone have relatively low sensitivity/specificity, and we advocate any threshold be used as part of a screening tool, along with other signs and symptoms of infection.

Activity analysis of thermal imaging videos using a difference imaging approach.

Infrared thermal imaging is a passive imaging technique that captures the emitted radiation from an object to estimate surface temperature, often for inference of heat transfer. Infrared thermal imaging offers the potential to detect movement without the challenges of glare, shadows, or changes in lighting associated with visual digital imaging or active infrared imaging. In this paper, we employ a frame subtraction algorithm for extracting the pixel-by-pixel relative change in signal from a fixed focus video file, tailored for use with thermal imaging videos. By summing the absolute differences across an entire video, we are able to assign quantitative activity assessments to thermal imaging data for comparison with simultaneous recordings of metabolic rates. We tested the accuracy and limits of this approach by analyzing movement of a metronome and provide an example application of the approach to a study of Darwin's finches. In principle, this "Difference Imaging Thermography" (DIT) would allow for activity data to be standardized to energetic measurements and could be applied to any radiometric imaging system.

Infrared cameras overestimate skin temperature during rewarming from cold exposure.

OBJECTIVE: The primary aim of this study was to assess the accuracy of an infrared camera and that of a skin thermistor, both commercially available. The study aimed to assess the agreement over a wide range of skin temperatures following cold exposure. METHODS: Fifty-two males placed their right hand in a thin plastic bag and immersed it in 8 °C water for 30 min whilst seated in an air temperature of 30 °C. Following hand immersion, participants removed the bag and rested their hand at heart level for 10 min. Index finger skin temperature (Tsk) was measured with a thermistor, affixed to the finger pad, and an infrared camera measured 1 cm distally to the thermistor. Agreement between the infrared camera and thermistor was assessed by mean difference (infrared camera minus thermistor) and 95% limits of agreement analysis, accounting for the repeated measures over time. The clinically significant threshold for Tsk differences was set at ±0.5 °C and limits of agreement ±1 °C. RESULTS: As an average across all time points, the infrared camera recorded Tsk 1.80 (SD 1.16) °C warmer than the thermistor, with 95% limits of agreement ranging from -0.46 °C to 4.07 °C. CONCLUSION: Collectively, the results show the infrared camera overestimated Tsk at every time point following local cooling. Further, measurement of finger Tsk from the infrared camera consistently fell outside the acceptable level of agreement (i.e. mean difference exceeding ±0.5 °C). Considering these results, infrared cameras may overestimate peripheral Tsk following cold exposure and clinicians and practitioners should, therefore, adjust their risk/withdrawal criteria accordingly.

[Thermographic monitoring of skin surface temperature associated with hot-iron disbudding in calves]. / Einsatz der Thermographie zum Monitoring der operationsbedingten Hitzeentwicklung während der thermischen Enthornung von Kälbern.

INTRODUCTION: The goal of this study was to determine the skin surface temperatures of the head using thermography in 28 German Holstein heifer calves at the time of hot iron disbudding. Calves were divided into group 1 (hot-iron disbudding, n = 14) and 2 (sham disbudding, n = 14). Thermographic measurements were made at eight locations of the head (area surrounding both horn buds, both horn buds, muzzle, mucous membranes of the muzzle, both eyes) at nine time points (- 60 min (basal value), time of disbudding, 5, 30, 60, 90, 120, 240 and 480 min after disbudding) using a high-end thermographic camera (ThermoPro TP8, Firma DIAS Infrared GmbH). The rectal temperature was measured 60 min before and 5, 240 and 480 min after disbudding. The statistical software SAS version 9.4 was used for analysis. Skin surface temperatures and rectal temperature correlated at several locations (rp ≥ 0.45; p ≤ 0.05). The maximum temperature (approx. 67 ºC) was measured at the horn buds immediately after the hot-iron procedure. By five and 30 min after hot-iron disbudding, the temperature of the horn buds had decreased by up to 50%, whereas the temperatures at the other locations had increased significantly (p.

INTRODUCTION: Le but de cette étude était de montrer les températures de surface dans la zone de tête chez 28 veaux femelles Holstein allemandes autour de la période d'écornage en utilisant la thermographie. À cette fin, les animaux étudiés ont été divisés en deux groupes (1: écornage thermique (thermE), N = 14; 2: pseudo-écornage (ScheinE), N = 14). À neuf reprises (- 60 [valeur au repos], 0, 5, 30, 60, 90, 120, 240, 480 min) des mesures thermographiques ont été effectuées à huit endroits dans la zone de la tête (environs du bourgeon de corne gauche (UliHa), bourgeon de corne gauche (liHa), œil gauche (liAu), mufle (FM), muqueuse nasale (SHFM), œil droit (reAu), bourgeon de corne droite (reHa), environs du bourgeon de corne droit (UreHa)). Ces mesures ont été réalisés à l'aide d'une caméra d'imagerie thermique haut de gamme (ThermoPro TP8, société DIAS Infrared GmbH). De plus, la température interne du corps (ICT) a été enregistrée par voie rectale aux minutes - 60, 5, 240 et 480. L'évaluation statistique de chaque caractéristique a été effectuée avec SAS, version 9.4. À plusieurs endroits (reAu, liAu, SHFM, liHa), une relation entre les ICT mesurées par voie rectale et les températures de surface déterminées par thermographie a pu être démontrée (rp ≥ 0,45; p ≤ 0,05). La température maximale (env. 67 °C) a pu être constatée au niveau des bourgeons de corne directement après l'écornage thermique. Cinq et 30 minutes après l'intervention, la température au niveau des bourgeons de corne avait diminué jusqu'à 50%, tandis que les températures de surface des autres emplacements chez les veaux des deux groupes avaient augmenté par rapport à la valeur au repos (p.

Immune Response Related With Skin Thermal Pattern in Judokas: A New Application for Infrared Thermography?

Brito, CJ, Moreira, DG, Ferreira, JJ, Díaz-de-Durana, AL, Miarka, B, Bouzas Marins, JC, and Sillero-Quintana, M. Immune response related with skin thermal pattern in judokas: A new application for infrared thermography? J Strength Cond Res 34(10): 2886-2894, 2020-This study investigated the association between body skin temperature (BST) and immune response after judo training, and compared the immune responses considering 2 post-training skin thermal pattern ("spots"-SPT and "localized"-LOC). For this, we evaluated 32 (25-male) black-belt judokas from the Spanish Junior National Team (18.0 ± 3.5 years, 72.4 ± 18.4 kg, and 17.1 ± 7.5% body fat). White blood cell and BST measurements were performed at pre-training, immediately, 1, and 24-hour post-training. Body skin temperature (° C) was estimated by skin temperature from 4 regions of interest (chest, upper arm, thigh, and calf). The main results indicated that 13 judokas were classified as SPT and 19 as LOC. In comparison with LOC, SPT had a significantly lower BST post-training (SPT = 33.0 ± 0.4 vs. LOC = 33.6 ± 0.8° C; p = 0.016), lower blood concentration of leukocytes (SPT = 7.9 ± 1.9 vs. LOC = 8.9 ± 1.9 cells × 10 per mm; p ≤ 0.001), and neutrophils (SPT = 5.5 ± 1.7 vs. LOC = 6.1 ± 2.2 cells × 10 per mm; p ≤ 0.001). In conclusion, the BST and immune response after judo training seem to be not associated. However, when the skin thermal pattern is considered, the SPT skin thermal pattern presented a lower post-training BST, blood leukocytes, and neutrophils in comparison with the LOC group. These results show a possible relationship between skin thermal pattern and immune responses for the first time; however, further studies are needed to confirm the evidence presented here.

Frontal infrared thermography in healthy individuals and chronic migraine patients: Reliability of the method.

BACKGROUND: The use of frontal infrared thermography in the diagnosis of primary headaches provided scattering results due to measurement fluctuations and different types of headaches or research protocols. OBJECTIVE: This study aims to assess the reliability of frontal infrared thermography in healthy individuals and provide a preliminary evaluation in chronic migraine patients using a commercial infrared thermal camera. METHODS: Thermographic images were acquired in 20 controls and 15 patients at three consecutive time-points in two daily sessions. The Side Difference and Asymmetry Index parameters were defined. The reproducibility of the measurements, the correlation of Asymmetry Index and Side Difference with clinical evaluations and patient perceptions, and the ability of the parameters to discriminate between patients and controls were investigated. RESULTS: We reported a good reproducibility of the measurements (Inter-class Correlation Coefficient > 0.75 and Coefficient of Variation < 13.4%), independent from external factors. The Side Difference was significantly different between patients and controls ( p < 0.001). The Asymmetry Index showed good correlation with the side of unilateral pain ( p = 0.0056). CONCLUSIONS: Frontal infrared thermography can be used to quantify the difference between the right and the left side of frontal vascular changes in chronic migraine patients, provided that standardized conditions are satisfied.

Relationship between residual feed intake and radiated heat loss using infrared thermography in young beef bulls.

Residual feed intake (RFI) has been used to select metabolically efficient cattle in beef breeding programs, particularly for sire selection. Adoption of genetic selection using RFI has been limited due to the cost and difficulty of measuring individual feed intake. An alternative method of predicting RFI is to measure radiated heat loss using infrared thermography (IRT) as previous studies have shown promise using this technique to predict metabolic efficiency in mature cows, heifers, and growing bulls. The objective of this study was to explore use of IRT to predict RFI in growing beef bulls. Sixty bulls in each of two years were fed either a forage-based or a grain-based ration. Eye (Ey) and cheek (Ck) surface temperatures were measured using infrared images of the head collected on 16 and 14 sample days in Years 1 and 2, respectively, using a FLIR S60 camera. In Year 2, infrared images were collected continuously using a within-pen FLIR A310 camera system. Bulls were grouped into low, medium and high classes based on ±â€¯0.5 standard deviations of backfat adjusted residual feed intake (RFIFat); RFIFat values ranged from - 2.27 to + 2.61 kg DM day-1 (mean=0.0; SD=0.61). Sample day Ey and Ck temperatures were pooled and an average temperature was calculated for individual bulls. Average Ey and Ck temperatures measured using the FLIR S60 and the within-pen camera did not differ significantly across low, medium and high RFI groups (P > 0.05). Temperature deviations associated with extremes in ambient temperature (placing animals outside their thermoneutral zone) or underlying subclinical health problems could bias results in IRT measurements and RFI ranking. Standardization of IRT data and the conditions during measurement is necessary to more accurately assess its potential use to predict RFI.

Best practices for standardized performance testing of infrared thermographs intended for fever screening.

Infrared (IR) modalities represent the only currently viable mass fever screening approaches for outbreaks of infectious disease pandemics such as Ebola virus disease and severe acute respiratory syndrome. Non-contact IR thermometers (NCITs) and IR thermographs (IRTs) have been used for fever screening in public areas such as airports. While NCITs remain a more popular choice than IRTs, there has been increasing evidences in the literature that IRTs can provide great accuracy in estimating body temperature if qualified systems are used and appropriate procedures are consistently applied. In this study, we addressed the issue of IRT qualification by implementing and evaluating a battery of test methods for objective, quantitative assessment of IRT performance based on a recent international standard (IEC 80601-2-59). We tested two commercial IRTs to evaluate their stability and drift, image uniformity, minimum resolvable temperature difference, and radiometric temperature laboratory accuracy. Based on these tests, we illustrated how experimental and data processing procedures could affect results, and suggested methods for clarifying and optimizing test methods. Overall, the insights into thermograph standardization and acquisition methods provided by this study may improve the utility of IR thermography and aid in comparing IRT performance, thus improving the potential for producing high quality disease pandemic countermeasures.

Body temperature of healthy men evaluated by thermography: A study of reproducibility.

BACKGROUND: Thermography is a safe, painless, and efficient method for checking the temperature of the skin. OBJECTIVE: Was to assess the pattern of skin temperature of healthy men, as well as to verify the reproducibility of the method. METHODS: This cross-sectional observational study was conducted with 30 men evaluated by thermography in two moments by using an infrared camera (FLIR +T650SC®). The skin temperature of 24 regions of interest (ROI) was measured. RESULTS: The mean difference in temperature of 10 ROIs in the two evaluations was not statistically significant. The comparisons of the ΔTsk between the right and left sides by the two evaluations showed no differences. The intra-class correlation coefficient (ICC) between the two moments of evaluation were statistically significant, where the dorsal measurements (Left forearm and Right dorsal arm) showed poor correlations and the others ranged from moderate to strong. Greater reproducibility was confirmed for ventral and dorsal hand ROIs; however, they presented the highest coefficient of variation (9% and 8%). CONCLUSION: There is a similarity between the temperatures of the ROIs and the reproducibility in 22 of the 24 ROIs varies from moderate to strong, showing that thermography is a reproducible method in healthy men.

3D brain tumor localization and parameter estimation using thermographic approach on GPU.

The aim of this paper is to present a GPU parallel algorithm for brain tumor detection to estimate its size and location from surface temperature distribution obtained by thermography. The normal brain tissue is modeled as a rectangular cube including spherical tumor. The temperature distribution is calculated using forward three dimensional Pennes bioheat transfer equation, it's solved using massively parallel Finite Difference Method (FDM) and implemented on Graphics Processing Unit (GPU). Genetic Algorithm (GA) was used to solve the inverse problem and estimate the tumor size and location by minimizing an objective function involving measured temperature on the surface to those obtained by numerical simulation. The parallel implementation of Finite Difference Method reduces significantly the time of bioheat transfer and greatly accelerates the inverse identification of brain tumor thermophysical and geometrical properties. Experimental results show significant gains in the computational speed on GPU and achieve a speedup of around 41 compared to the CPU. The analysis performance of the estimation based on tumor size inside brain tissue also presented.

An automated approach to enhance the thermographic evaluation on orofacial regions in lateral facial thermograms.

Segmentation of characteristic facial regions has often been an initial step of thermographic analysis in face recognition and clinical diagnosis. Moreover, fast and accurate thermographic analysis on characteristic areas is highly reliant on segmentation approach. Usually, frontal and lateral projections are used to capture the facial thermograms. The significant role of lateral facial thermography to diagnose the various problems associated with orofacial regions has been remarkable in many studies. So far, no study has presented an automatic approach for the segmentation of characteristic areas in lateral facial thermograms. For this purpose, an automatic approach to segment the characteristic areas in lateral facial thermograms is proposed. The dataset of 140 facial thermograms with 1 left and 1 right lateral view per subject is created. Initially, image binarization is performed using optimal temperature thresholding for better visualization of facial geometry. Then, the automatic localization of characteristic points is performed at two levels, based on (a) geometrical features of the face, and (b) local thermal patterns. At last, the characteristic points and auxiliary points are used to segment the characteristic areas in the orofacial region of the face. To evaluate the segmentation performance of the proposed methodology, the automatically localized characteristic points are compared with manually marked using Euclidean distance based comparison criterion. With the localization error δch_pt≤0.05, the proposed automatic approach shows 92.04% of overall localization accuracy and 85% of overall segmentation accuracy. The key conclusion is that the proposed algorithm can potentially automate the process of thermographic analysis on characteristic areas to assist the diagnosis of problems in the orofacial region.

Evaluation of liver fibrosis using Raman spectroscopy and infrared thermography: A pilot study.

Liver fibrosis is a pathological process that can escalate to cirrhosis and then liver failure, a major public health concern that affect hundreds of millions of people in both developed and developing countries. Detection of liver fibrosis during its earlier stages is a matter of great importance which may allow prevention of development of cirrhosis in patients with chronic liver disease. In this work, Raman spectroscopy and thermography were evaluated to detect early pathological signs of liver fibrosis in rats in which liver fibrosis was induced using carbon tetrachloride. Results show that Raman spectra of healthy and fibrotic livers significantly differ among each other and can be classified by principal component analysis and discriminant analysis. The PCA-LDA method has a sensitivity of 100%, specificity 85% and diagnostic accuracy of 93.5%. Thermography also revealed characteristic temperature patterns for fibrotic livers compared to healthy livers. Current data suggest that Raman spectroscopy and thermography could be used to detect fibrosis in ex vivo liver samples.

Thermal Modeling for the Next Generation of Radiofrequency Exposure Limits: Commentary.

This commentary evaluates two sets of guidelines for human exposure to radiofrequency (RF) energy, focusing on the frequency range above the "transition" frequency at 3-10 GHz where the guidelines change their basic restrictions from specific absorption rate to incident power density, through the end of the RF band at 300 GHz. The analysis is based on a simple thermal model based on Pennes' bioheat equation (BHTE) (Pennes 1948) assuming purely surface heating; an Appendix provides more details about the model and its range of applicability. This analysis suggests that present limits are highly conservative relative to their stated goals of limiting temperature increase in tissue. As applied to transmitting devices used against the body, they are much more conservative than product safety standards for touch temperature for personal electronics equipment that are used in contact with the body. Provisions in the current guidelines for "averaging time" and "averaging area" are not consistent with scaling characteristics of the bioheat equation and should be refined. The authors suggest the need for additional limits on fluence for protection against brief, high intensity pulses at millimeter wave frequencies. This commentary considers only thermal hazards, which form the basis of the current guidelines, and excludes considerations of reported "non-thermal" effects of exposure that would have to be evaluated in the process of updating the guidelines.

[FRONTAL, AXILLARY AND TYMPANIC TEMPERATURE MEASUREMENTS IN CHILDREN]. / TIMPANICNA, FRONTALNA I AKSILARNA TEMPERATURA U DJECE.

The purpose of this study was to compare the results of body temperature measurements obtained by standard axillary thermometers with the results of infrared tympanic and frontal skin thermometry in afebrile children. This study comprises a single-center, prospective comparison trial. A total of 345 afebrile children aged 4 to 16 years hospitalized in the pediatric surgery department for elective surgery were included. One thousand axillary, tympanic and frontal measurements were obtained and compared. We used two different infrared thermometers in this study; one type measured the tympanic temperature, the other the temperature on the forehead. The axillary temperature measured with the glass thermometer was set as the standard. Each patient was exposed to a constant environmental temperature for a minimum of 10 min before simultaneous temperature measurements. The mean-frontal temperature 36.9 ± 0.38 °C was equal to the axillary temperature 36.9 ± 0.16 °C. The mean tympanic temperature was 36.3 ± 0.98 °C. The mean difference between the tympanic and axillary temperatures was -0.4 °C. The tympanic temperature had a threefold greater dispersion than frontal and a fivefold greater dispersion than axillary temperature. The results of this study suggest that the axillary temperature measured with glass thermometer has the least dispersion. Somewhat less reliable is the frontal temperature measured with infrared thermometer. The least reliable is tympanic temperature measurement.

Calibration and Evaluation of Ultrasound Thermography Using Infrared Imaging.

Real-time monitoring of the spatiotemporal evolution of tissue temperature is important to ensure safe and effective treatment in thermal therapies including hyperthermia and thermal ablation. Ultrasound thermography has been proposed as a non-invasive technique for temperature measurement, and accurate calibration of the temperature-dependent ultrasound signal changes against temperature is required. Here we report a method that uses infrared thermography for calibration and validation of ultrasound thermography. Using phantoms and cardiac tissue specimens subjected to high-intensity focused ultrasound heating, we simultaneously acquired ultrasound and infrared imaging data from the same surface plane of a sample. The commonly used echo time shift-based method was chosen to compute ultrasound thermometry. We first correlated the ultrasound echo time shifts with infrared-measured temperatures for material-dependent calibration and found that the calibration coefficient was positive for fat-mimicking phantom (1.49 ± 0.27) but negative for tissue-mimicking phantom (-0.59 ± 0.08) and cardiac tissue (-0.69 ± 0.18°C-mm/ns). We then obtained the estimation error of the ultrasound thermometry by comparing against the infrared-measured temperature and revealed that the error increased with decreased size of the heated region. Consistent with previous findings, the echo time shifts were no longer linearly dependent on temperature beyond 45°C-50°C in cardiac tissues. Unlike previous studies in which thermocouples or water bath techniques were used to evaluate the performance of ultrasound thermography, our results indicate that high-resolution infrared thermography is a useful tool that can be applied to evaluate and understand the limitations of ultrasound thermography methods.

Ultrasensitive, Biocompatible, Self-Calibrating, Multiparametric Temperature Sensors.

Core-shell quantum dots serve as self-calibrating, ultrasensitive, multiparametric, near-infrared, and biocompatible temperature sensors. They allow temperature measurement with nanometer accuracy in the range 150-373 K, the broadest ever recorded for a nanothermometer, with sensitivities among the highest ever reported, which makes them essentially unique in the panorama of biocompatible nanothermometers with potential for in vivo biological thermal imaging and/or thermoablative therapy.

Assessment of the Sensitivity, Specificity, and Accuracy of Thermography in Identifying Patients with TMD.

BACKGROUND: The purpose of the present study was to evaluate the sensitivity, specificity, and accuracy of thermography in identifying patients with temporomandibular dysfunction (TMD). MATERIAL AND METHODS: The study sample consisted of 50 patients (27 women and 23 men) ages 19.2 to 24.5 years (mean age 22.43±1.04) with subjective symptoms of TMD (Ai II-III) and 50 patients (25 women and 25 men) ages 19.3 to 25.1 years (mean age 22.21±1.18) with no subjective symptoms of TMD (Ai I). The anamnestic interviews were conducted according to the three-point anamnestic index of temporomandibular dysfunction (Ai). The thermography was performed using a ThermaCAM TMSC500 (FLIR Systems AB, Sweden) independent thermal vision system. Thermography was closely combined with a 10-min chewing test. RESULTS: The results of our study indicated that the absolute difference in temperature between the right and left side (ΔT) has the highest diagnostic value. The diagnostic effectiveness of this parameter increased after the chewing test. The cut-off points for values of temperature differences between the right and left side and identifying 95.5% of subjects with no functional disorders according to the temporomandibular dysfunction index Di (specificity 95.5%) were 0.26°C (AUC=0.7422, sensitivity 44.3%, accuracy 52.4%) before the chewing test and 0.52°C (AUC=0.7920, sensitivity 46.4%, accuracy 56.3%) after it. CONCLUSIONS: The evaluation of thermography demonstrated its diagnostic usefulness in identifying patients with TMD with limited effectiveness. The chewing test helped in increasing the diagnostic efficiency of thermography in identifying patients with TMD.