RESUMEN
Skin cancer is the most common cancer of the body. It is estimated that more than one million people worldwide develop skin cancer each year. Early detection of this cancer has a high effect on the disease treatment. In this paper, a new optimal and automatic pipeline approach has been proposed for the diagnosis of this disease from dermoscopy images. The proposed method includes a noise reduction process before processing for eliminating the noises. Then, the Otsu method as one of the widely used thresholding method is used to characterize the region of interest. Afterward, 20 different features are extracted from the image. To reduce the method complexity, a new modified version of the Thermal Exchange Optimization Algorithm is performed to the features. This improves the method precision and consistency. To validate the proposed method's efficiency, it is implemented to the American Cancer Society database, its results are compared with some state-of-the-art methods, and the final results showed the superiority of the proposed method against the others.
Asunto(s)
Algoritmos , Dermoscopía/métodos , Melanoma/diagnóstico por imagen , Neoplasias Cutáneas/diagnóstico por imagen , Biología Computacional , Heurística Computacional , Simulación por Computador , Bases de Datos Factuales , Aprendizaje Profundo , Dermoscopía/estadística & datos numéricos , Detección Precoz del Cáncer/métodos , Detección Precoz del Cáncer/estadística & datos numéricos , Humanos , Interpretación de Imagen Asistida por Computador/métodos , Interpretación de Imagen Asistida por Computador/estadística & datos numéricos , Melanoma/clasificación , Reconocimiento de Normas Patrones Automatizadas/métodos , Reconocimiento de Normas Patrones Automatizadas/estadística & datos numéricos , Relación Señal-Ruido , Neoplasias Cutáneas/clasificación , Máquina de Vectores de Soporte , Termografía/métodos , Termografía/estadística & datos numéricosRESUMEN
The aim of this study was to evaluate the correlation between tools commonly used in the detection of physiological changes, such as clinical complaints, a biochemical marker of muscle injury, and performance data during official matches, with infrared thermography, which has been commonly used in the possible tracking of musculoskeletal injuries in athletes. Twenty-two athletes from a professional soccer club (age 27.7 ± 3.93 years; BMI 24.35 ± 1.80 kg/cm2) were followed during the season of a national championship, totaling 19 matches with an interval of 7 days between matches. At each match, the athletes used a Global Positioning System (GPS) device to collect performance data. Forty-eight hours after each match, every athlete's perception of recovery, fatigue, and pain was documented. Blood was collected for creatine kinase (CK) analysis, and infrared thermography was applied. Only athletes who presented pain above 4 in either limb were included for thermographic analysis. Each thermographic image was divided into 14 regions of interest. For statistical analysis, we included only the images that showed differences ≥ 1° C. Data normality was verified by the Kolmogorov-Smirnov test with Dallal-Wilkinson-Lilliefors correction. We used the Pearson correlation coefficient to verify the correlation between infrared thermography and the biochemical marker, performance data, and clinical recovery scales. No correlation was observed between mean skin temperature and blood CK levels, pain level, perception of recovery, and fatigue perception (r <0.2, p>0.05). Thus, infrared thermography did not correlate with CK level, pain, fatigue perception, or recovery, nor with performance variables within the field.
Asunto(s)
Rendimiento Atlético/fisiología , Monitoreo Fisiológico/métodos , Temperatura Cutánea/fisiología , Termografía/métodos , Adulto , Atletas/estadística & datos numéricos , Biomarcadores/sangre , Creatina Quinasa/sangre , Estudios Transversales , Femenino , Sistemas de Información Geográfica , Humanos , Extremidad Inferior , Masculino , Monitoreo Fisiológico/instrumentación , Monitoreo Fisiológico/estadística & datos numéricos , Tecnología de Sensores Remotos/instrumentación , Fútbol/fisiología , Termografía/estadística & datos numéricos , Adulto JovenRESUMEN
OBJECTIVE: To determine the frequency and predictors of temperature measurement at well-child visits in the US and report rates of interventions associated with visits at which temperature is measured and fever is detected. STUDY DESIGN: In this cross-sectional study, we analyzed 22 518 sampled well-child visits from the National Ambulatory Medical Care Survey between 2003 and 2015. We estimated the frequency of temperature measurement and performed multivariable regression to identify patient, provider/clinic, and seasonal factors associated with the practice. We described rates of interventions (complete blood count, radiograph, urinalysis, antibiotic prescription, and emergency department/hospital referral) by measurement and fever (temperature ≥100.4 °F, ≥38.0 °C) status. RESULTS: Temperature was measured in 48.5% (95% CI 45.6-51.4) of well-child visits. Measurement was more common during visits by nonpediatric providers (aOR 2.0, 95% CI 1.6-2.5; reference: pediatricians), in Hispanic (aOR 1.9, 95% CI 1.6-2.3) and Black (aOR 1.5, 95% CI 1.2-1.9; reference: non-Hispanic White) patients, and in patients with government (aOR 2.0, 95% CI 1.7-2.4; reference: private) insurance. Interventions were more commonly pursued when temperature was measured (aOR 1.3, 95% CI 1.1-1.6) and fever was detected (aOR 3.8, 95% CI 1.5-9.4). CONCLUSIONS: Temperature was measured in nearly one-half of all well-child visits. Interventions were more common when temperature was measured and fever was detected. The value of routine temperature measurement during well-child visits warrants further evaluation.
Asunto(s)
Temperatura Corporal , Fiebre/diagnóstico , Pautas de la Práctica en Medicina/estadística & datos numéricos , Servicios Preventivos de Salud/métodos , Atención Primaria de Salud/métodos , Termografía/estadística & datos numéricos , Adolescente , Niño , Preescolar , Estudios Transversales , Femenino , Fiebre/etiología , Fiebre/terapia , Encuestas de Atención de la Salud , Humanos , Lactante , Recién Nacido , Modelos Logísticos , Masculino , Análisis Multivariante , Servicios Preventivos de Salud/estadística & datos numéricos , Atención Primaria de Salud/estadística & datos numéricos , Estudios Retrospectivos , Termografía/métodos , Estados UnidosRESUMEN
Vespa velutina is an invasive hornet species that is colonising Europe, generating considerable impacts on honeybees, beekeeping and biodiversity. Control and early warning strategies for this species are mainly based on monitoring plans and procedures of nest detection and destruction. Technological tools (harmonic radar, radio-telemetry) have been developed to increase the probabilities of nest detection in new outbreaks. Since hornets are able to regulate nest temperature, thermography may represent an additional technique that may be used, both alone or in support to other techniques. In this study, the viability of thermal imaging in detecting nests of V. velutina was evaluated in controlled conditions. The influence of different environmental and operative variables (time of the day, presence/absence of leaves covering the nest, distance between the nest and the operator) were tested on three nests detected during August 2018 in Italy. All the nests were detectable by thermal imaging, but environmental and operative variables affect their detectability. The temperature difference between the nests and the surrounding reaches its maximum before sunrise and without a tree canopy covering the nests. Although nests were visible in some cases from 30 m, the detectability was higher at shorter distances, even if this variable may also depend on infrared camera resolution. An increase in the environmental temperature also generates a decrease of nest detectability. Although some limitations could occur, these results show the applicability of thermography in detecting V. velutina nests before the beginning of the reproductive phase, and consequently its potentiality in control strategies.
Asunto(s)
Especies Introducidas , Comportamiento de Nidificación , Termografía/métodos , Avispas/fisiología , Animales , Italia , Termografía/estadística & datos numéricosRESUMEN
Vascular malformations classification may pose a diagnostic challenge for physicians. In the early stages, they are diagnosed clinically mainly by visual inspection. For a deeper analysis, Doppler ultrasonography is the preferred technique to determine the haemodynamic behaviour of the anomaly. However, this imaging method is not always available and it requires trained operators to acquire and interpret the images. There is a lack of portable and user-friendly systems that may help physicians in the assessment of vascular malformations. We propose a new diagnostic procedure, more affordable and easier to use, based on a portable thermal camera. This technique provides information about temperature, which has been found to be correlated with the flow rate of the lesion. In our study, > 60 vascular malformations of previously diagnosed patients were analysed with a thermal camera to classify them into low-flow and high-flow malformations. The value was 1 for both sensitivity and specificity of this technique.
Asunto(s)
Termografía/instrumentación , Termografía/estadística & datos numéricos , Malformaciones Vasculares/diagnóstico , Velocidad del Flujo Sanguíneo/fisiología , Temperatura Corporal/fisiología , Diagnóstico Diferencial , Hemodinámica/fisiología , Humanos , Sensibilidad y Especificidad , Termografía/economía , Termografía/métodos , Ultrasonografía Doppler/métodos , Ultrasonografía Doppler/normas , Malformaciones Vasculares/clasificación , Malformaciones Vasculares/patologíaRESUMEN
Although plantar thermography can evaluate the immediate perfusion result after an endovascular therapy (EVT) has been performed, a relevant wound outcome study is still lacking.This study was to investigate whether angiosome-based plantar thermography could predict wound healing and freedom from major amputation after EVT in patients with critical limb ischemia (CLI).All 124 patients with CLI (Rutherford category 5 and 6) who underwent EVT from January 2017 to February 2019 were prospectively enrolled. All patients received thermography both before and after EVT. Both wound healing and freedom from major amputation at the 6-month follow-up period were recorded. There were 61 patients in the healing group and 63 patients in the non-healing group, whereas the major amputation total was 14 patients. The mean pre- and post-EVT temperature of the foot was significantly higher in the healing group than in the non-healing group (30.78â°C vs 29.42â°C, Pâ=â.015; and 32.34â°C vs 30.96â°C, Pâ=â.004, respectively). DIFF2 was significantly lower in the non-healing group (-1.38 vs -0.90, Pâ=â.009). DIFF1 and DIFF2 were significantly lower in the amputation group (-1.85â°C vs -1.11â°C, Pâ=â.026; and -1.82â°C vs -1.08â°C, Pâ=â.004). Multivariate analysis showed that DIFF2 stood out as an independent predictor for freedom from major amputation (hazard ratio 0.51, Pâ=â.045). Receiver operating characteristic curve analysis showed a DIFF2 cut-off value of -1.30â°C, which best predicts freedom from major amputation.Plantar thermography is associated with wound healing and helps predict freedom from major amputation in CLI patients undergoing EVT.
Asunto(s)
Extremidades/cirugía , Isquemia/cirugía , Termografía/métodos , Anciano , Anciano de 80 o más Años , Amputación Quirúrgica , Procedimientos Endovasculares/métodos , Extremidades/fisiopatología , Femenino , Humanos , Isquemia/complicaciones , Recuperación del Miembro/métodos , Masculino , Persona de Mediana Edad , Modelos de Riesgos Proporcionales , Termografía/estadística & datos numéricosRESUMEN
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.
Asunto(s)
Envejecimiento/fisiología , Temperatura Corporal/fisiología , COVID-19 , Casas de Salud/estadística & datos numéricos , Termografía , Servicios de Salud para Veteranos/estadística & datos numéricos , Anciano de 80 o más Años , COVID-19/diagnóstico , COVID-19/epidemiología , COVID-19/fisiopatología , Prueba de COVID-19/métodos , Precisión de la Medición Dimensional , Femenino , Hogares para Ancianos/estadística & datos numéricos , Humanos , Masculino , Tamizaje Masivo/métodos , Tamizaje Masivo/normas , SARS-CoV-2 , Sensibilidad y Especificidad , Termografía/métodos , Termografía/normas , Termografía/estadística & datos numéricos , Estados Unidos/epidemiologíaRESUMEN
In this research, 56 samples of pure honey have been mixed with different concentrations of rice syrup simulating a set of adulterated samples. A thermographic camera was used to extract data regarding the thermal development of the honey. The resulting infrared images were processed via convolutional neural networks (CNNs), a subset of algorithms within deep learning. The CNNs have been trained and optimized using these images to detect the commonly elusive rice syrup in honey in concentrations as low as 1% in weight, as well as quantify it. Finally, the model was successfully validated using images which were initially isolated from the training database. The result was an algorithm capable of identifying adulterated honey from different floral origins and quantifying rice syrup with accuracies of 95% and 93%, respectively. Therefore, CNNs have complemented the thermographic analysis and have shown to be a compelling tool for the control of food quality, thanks to traits such as high sensitivity, speed, and being independent of highly specialized personnel.
Asunto(s)
Contaminación de Alimentos/análisis , Miel/análisis , Redes Neurales de la Computación , Termografía/estadística & datos numéricos , Oryza/química , Factores de TiempoRESUMEN
BACKGROUND AND OBJECTIVE: Liver quality evaluation is one of the vital steps for predicting the success of liver transplantation. Current evaluation methods, such as biopsy and visual inspection, which are either invasive or lack of consistent standards, provide limited predictive value of long-term transplant viability. Objective analytical models, based on the real-time infrared images of livers during perfusion and preservation, are proposed as novel methods to precisely evaluate donated liver quality. METHODS: In this study, by using principal component analysis to extract infrared image features as predictors, we construct a multivariate logistic regression model for single liver quality evaluation, and a multi-task learning logistic regression model for cross-liver quality evaluation. RESULTS: The single liver quality predictions show testing errors of 0%. The leave-one-liver-out predictions show testing errors ranging from 9% to 36%. CONCLUSIONS: It is found that there is a strong correlation between the viability of livers and the infrared image features in both single liver and cross-liver quality evaluations. These analytical methods also determine that the selected significant infrared image features indicate regional difference in viability and show that more stringent pre-implantation evaluation may be needed to predict transplant outcomes.
Asunto(s)
Interpretación de Imagen Asistida por Computador/métodos , Trasplante de Hígado , Hígado/diagnóstico por imagen , Termografía/métodos , Animales , Humanos , Interpretación de Imagen Asistida por Computador/estadística & datos numéricos , Rayos Infrarrojos , Trasplante de Hígado/normas , Modelos Logísticos , Modelos Animales , Análisis Multivariante , Análisis de Componente Principal , Porcinos , Termografía/estadística & datos numéricosRESUMEN
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.
Asunto(s)
Fiebre/diagnóstico , Termografía/métodos , Termografía/normas , Aeropuertos , Enfermedades Transmisibles/diagnóstico , Enfermedades Transmisibles/epidemiología , Brotes de Enfermedades , Humanos , Rayos Infrarrojos , Tamizaje Masivo/métodos , Tamizaje Masivo/normas , Tamizaje Masivo/estadística & datos numéricos , Guías de Práctica Clínica como Asunto/normas , Termografía/estadística & datos numéricos , TermómetrosRESUMEN
OBJECTIVE: Reliable and objective outcome measures to facilitate clinical trials of novel treatments for systemic sclerosis (SSc)-related Raynaud's phenomenon (RP) are badly needed. Laser speckle contrast imaging (LSCI) and thermography are noninvasive measures of perfusion that have shown excellent potential. This multicenter study was undertaken to determine the reliability and validity of a hand cold challenge protocol using LSCI, standard thermography, and low-cost cell phone/mobile phone thermography (henceforth referred to as mobile thermography) in patients with SSc-related RP. METHODS: Patients with RP secondary to SSc were recruited from 6 UK tertiary care centers. The patients underwent cold challenge on 2 consecutive days. Changes in cutaneous blood flow/skin temperature at each visit were imaged simultaneously using LSCI, standard thermography, and mobile thermography. Measurements included area under the curve (AUC) for reperfusion/rewarming and maximum blood flow rate/skin temperature after rewarming (MAX). Test-retest reliability was assessed using intraclass correlation coefficients (ICCs). Estimated latent correlations (estimated from multilevel models, taking values between -1 and 1; denoted as rho values) were used to assess the convergent validity of LSCI and thermography. RESULTS: In total, 159 patients (77% with limited cutaneous SSc) were recruited (84% female, median age 63.3 years). LSCI and standard thermography both had substantial reliability, with ICCs for the reperfusion/rewarming AUC of 0.67 (95% confidence interval [95% CI] 0.54, 0.76) and 0.68 (95% CI 0.58, 0.80), respectively, and ICCs for the MAX of 0.64 (95% CI 0.52, 0.75) and 0.72 (95% CI 0.64, 0.81), respectively. Very high latent correlations were present for the AUCs of LSCI and thermography (ρ = 0.94; 95% CI 0.87, 1.00) and for the AUCs of standard and mobile thermography (ρ = 0.98; 95% CI 0.94, 1.00). CONCLUSION: This is the first multicenter study to examine the reliability and validity of cold challenge using LSCI and thermography in patients with SSc-related RP. LSCI and thermography both demonstrated good potential as outcome measures. LSCI, standard thermography, and mobile thermography had very high convergent validity.
Asunto(s)
Técnicas de Diagnóstico Cardiovascular/estadística & datos numéricos , Evaluación de Resultado en la Atención de Salud/métodos , Enfermedad de Raynaud/diagnóstico por imagen , Esclerodermia Sistémica/complicaciones , Termografía/estadística & datos numéricos , Anciano , Área Bajo la Curva , Frío , Medios de Contraste , Estudios de Factibilidad , Femenino , Dedos/irrigación sanguínea , Dedos/diagnóstico por imagen , Mano/irrigación sanguínea , Mano/diagnóstico por imagen , Humanos , Rayos Láser , Masculino , Persona de Mediana Edad , Variaciones Dependientes del Observador , Enfermedad de Raynaud/etiología , Flujo Sanguíneo Regional , Reproducibilidad de los Resultados , Temperatura Cutánea , Estadísticas no Paramétricas , Termografía/métodosRESUMEN
Skin temperature may help prospectively determine whether an area of skin discoloration will evolve into necrosis. A prospective, observational study was conducted in 7 skilled nursing facilities to determine if skin temperature measured using infrared thermography could predict the progression of discolored intact skin (blanchable erythema, Stage 1 pressure ulcer, or sus- pected deep tissue injury [sDTI]) to necrosis and to evaluate if nurses could effectively integrate thermography into the clinical setting. Patients residing in or presenting to the facility between October 2014 and August 2015 with a pressure-related area of discolored skin determined to be blanchable erythema, a Stage 1 pressure ulcer, or sDTI and anticipated length of stay >6 days were assessed at initial presentation of the discolored area and after 7 and 14 days by facility nurses trained on camera operation and study protocol. Variables included patient demographic and clinical data, data related to the discolored area (eg, size, date of initial discovery), and temperature and appearance differences between discolored and adjacent intact skin. Skin temperatures at the discolored and adjacent areas were measured during the initial assessment. All facility pressure ulcer prevention and treatment protocols derived from evidence-based clinical practice guidelines remained in use during the study time period. Participating nurses completed a 2-part, pencil/paper survey to examine the feasibility of incorporating thermography for skin assessment into practice. Data analyses were performed using descriptive statistics (frequency analyses) and bivariate analysis (t-tests and chi-squared tests); logistic regression was used to assess associations among patient and pressure ulcer variables. Of the 67 patients studied, the overall mean age was 85 years (SD 10); 52 were women; 63 were Caucasian; and the top 3 diagnoses, accounting for 60% of the study sample, included neurologic (ie, cardiovascular acci- dent/dementia [14, 21%]), cardiac-related (14, 21%), and orthopedic (13, 19%) conditions. Twenty-eight (28) participants were long-term care patients, and 39 were admitted as short-stay patients. The most frequently reported location of discolored intact skin on presentation was the heel (27, 40%). The mean temperature at the site of the discolored skin was 33.6 Ì C (SD 3) and at the adjacent skin was 33.5 Ì C (SD 2.5). The mean size of the areas of discoloration was 11 cm2 (SD 21). Capillary refill of the discolored area was absent on initial presentation in 49 patients (72%), and demarcation of the discolored borders was evident for 45 (66%). Of the 67 patients, 30 (45%) experienced complete resolution of the discolored area. At day 7, 8 (16%) of the remaining 50 patients in the sample exhibited skin necrosis and at day 14, a total of 12 patients of the remaining 37 (32%) exhibited skin necrosis. At day 7, skin necrosis was significantly associated with admission to a subacute unit (P = 0.01) and at day 14 to negative capillary refill at initial presentation (P = 0.02). Regardless of skin temperature, negative capillary refill at presentation was significantly associated with skin necrosis at day 7 (P = 0.04). A dichotomous variable was constructed to examine patients with cooler temperatures at the site as compared to their adjacent skin and persons with warmer skin temperatures at the center of the discolored skin for the presence of skin necrosis at both day 7 and day 14. In multivariate analysis, patients with cooler rather than warmer skin temperatures at the center of the discolored area as compared to the adjacent skin were more likely to develop necrosis by day 7 (OR 18.8; P = 0.05; CI: 104-342.44). Participating nurses were uncertain about the feasibility of integrating thermography into practice. Larger prospective studies with more heterogeneous samples are needed to determine the validity of skin temperature measurement as a predictor of skin necrosis and the utility of implementing thermography into clinical practice.
Asunto(s)
Necrosis/diagnóstico , Temperatura Cutánea/fisiología , Termografía/estadística & datos numéricos , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Necrosis/fisiopatología , New England , Evaluación en Enfermería/métodos , Úlcera por Presión/prevención & control , Estudios Prospectivos , Instituciones de Cuidados Especializados de Enfermería/organización & administración , Cuidados de la Piel/métodos , Cuidados de la Piel/normas , Termografía/instrumentaciónRESUMEN
Infrared thermography is a non-invasive technique that measures mid to long-wave infrared radiation emanating from all objects and converts this to temperature. As an imaging technique, the value of modern infrared thermography is its ability to produce a digitized image or high speed video rendering a thermal map of the scene in false colour. Since temperature is an important environmental parameter influencing animal physiology and metabolic heat production an energetically expensive process, measuring temperature and energy exchange in animals is critical to understanding physiology, especially under field conditions. As a non-contact approach, infrared thermography provides a non-invasive complement to physiological data gathering. One caveat, however, is that only surface temperatures are measured, which guides much research to those thermal events occurring at the skin and insulating regions of the body. As an imaging technique, infrared thermal imaging is also subject to certain uncertainties that require physical modelling, which is typically done via built-in software approaches. Infrared thermal imaging has enabled different insights into the comparative physiology of phenomena ranging from thermogenesis, peripheral blood flow adjustments, evaporative cooling, and to respiratory physiology. In this review, I provide background and guidelines for the use of thermal imaging, primarily aimed at field physiologists and biologists interested in thermal biology. I also discuss some of the better known approaches and discoveries revealed from using thermal imaging with the objective of encouraging more quantitative assessment.
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Termografía/veterinaria , Aclimatación , Animales , Temperatura Corporal , Radiación Electromagnética , Congelación , Rayos Infrarrojos , Modelos Biológicos , Modelos Teóricos , Termogénesis , Termografía/métodos , Termografía/estadística & datos numéricosRESUMEN
Breast thermography still has inherent limitations that prevent it from being fully accepted as a breast screening modality in medicine. The main challenges of breast thermography are to reduce false positive results and to increase the sensitivity of a thermogram. Further, it is still difficult to obtain information about tumour parameters such as metabolic heat, tumour depth and diameter from a thermogram. However, infrared technology and image processing have advanced significantly and recent clinical studies have shown increased sensitivity of thermography in cancer diagnosis. The aim of this paper is to study numerically the possibilities of extracting information about the tumour depth from steady state thermography and transient thermography after cold stress with no need to use any specific inversion technique. Both methods are based on the numerical solution of Pennes bioheat equation for a simple three-dimensional breast model. The effectiveness of two approaches used for depth detection from steady state thermography is assessed. The effect of breast density on the steady state thermal contrast has also been studied. The use of a cold stress test and the recording of transient contrasts during rewarming were found to be potentially suitable for tumour depth detection during the rewarming process. Sensitivity to parameters such as cold stress temperature and cooling time is investigated using the numerical model and simulation results reveal two prominent depth-related characteristic times which do not strongly depend on the temperature of the cold stress or on the cooling period.
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Neoplasias de la Mama/diagnóstico , Termografía/métodos , Neoplasias de la Mama/patología , Neoplasias de la Mama/fisiopatología , Frío , Simulación por Computador , Femenino , Humanos , Interpretación de Imagen Asistida por Computador/métodos , Informática Médica/métodos , Informática Médica/estadística & datos numéricos , Modelos Biológicos , Temperatura Cutánea/fisiología , Estrés Fisiológico , Termografía/estadística & datos numéricosRESUMEN
Thermal infrared imaging has been proposed as a potential system for the computational assessment of human autonomic nervous activity and psychophysiological states in a contactless and noninvasive way. Through bioheat modeling of facial thermal imagery, several vital signs can be extracted, including localized blood perfusion, cardiac pulse, breath rate, and sudomotor response, since all these parameters impact the cutaneous temperature. The obtained physiological information could then be used to draw inferences about a variety of psychophysiological or affective states, as proved by the increasing number of psychophysiological studies using thermal infrared imaging. This paper presents therefore a review of the principal achievements of thermal infrared imaging in computational physiology with regard to its capability of monitoring psychophysiological activity.
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Psicometría/métodos , Psicofisiología/métodos , Termografía/métodos , Sistema Nervioso Autónomo/fisiología , Respuesta Galvánica de la Piel , Frecuencia Cardíaca , Humanos , Rayos Infrarrojos , Modelos Neurológicos , Modelos Psicológicos , Psicometría/estadística & datos numéricos , Psicofisiología/estadística & datos numéricos , Frecuencia Respiratoria , Piel/irrigación sanguínea , Estrés Fisiológico , Estrés Psicológico , Sudoración , Termografía/estadística & datos numéricosRESUMEN
OBJECTIVE: Musculoskeletal injuries occur frequently. Diagnostic tests using ionizing radiation can lead to problems for patients, and infrared thermal imaging could be useful when diagnosing these injuries. CONCLUSION: A systematic review was performed to determine the diagnostic accuracy of infrared thermal imaging in patients with musculoskeletal injuries. A meta-analysis of three studies evaluating stress fractures was performed and found a lack of support for the usefulness of infrared thermal imaging in musculoskeletal injuries diagnosis.
Asunto(s)
Fracturas Óseas/diagnóstico , Fracturas Óseas/epidemiología , Músculo Esquelético/lesiones , Traumatismos de los Tejidos Blandos/diagnóstico , Traumatismos de los Tejidos Blandos/epidemiología , Termografía/estadística & datos numéricos , Humanos , Rayos Infrarrojos , Pautas de la Práctica en Medicina/estadística & datos numéricos , Prevalencia , Factores de RiesgoRESUMEN
A quasi-Poisson generalized linear model combined with a distributed lag non-linear model was used to quantify the main effect of temperature on emergency department visits (EDVs) for childhood diarrhea in Brisbane from 2001 to 2010. Residual of the model was checked to examine whether there was an added effect due to heat waves. The change over time in temperature-diarrhea relation was also assessed. Both low and high temperatures had significant impact on childhood diarrhea. Heat waves had an added effect on childhood diarrhea, and this effect increased with intensity and duration of heat waves. There was a decreasing trend in the main effect of heat on childhood diarrhea in Brisbane across the study period. Brisbane children appeared to have gradually adapted to mild heat, but they are still very sensitive to persistent extreme heat. Development of future heat alert systems should take the change in temperature-diarrhea relation over time into account.
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Clima , Diarrea/epidemiología , Servicio de Urgencia en Hospital/estadística & datos numéricos , Trastornos de Estrés por Calor/epidemiología , Modelos Estadísticos , Imágenes Satelitales/estadística & datos numéricos , Niño , Preescolar , Simulación por Computador , Monitoreo del Ambiente/estadística & datos numéricos , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Queensland/epidemiología , Temperatura , Termografía/estadística & datos numéricosRESUMEN
The purpose of this study was to evaluate magnetic resonance (MR) temperature imaging of the laser-induced thermotherapy (LITT) comparing the proton resonance frequency (PRF) and T 1 thermometry methods. LITT was applied to a liver-mimicking acrylamide gel phantom. Temperature rise up to 70 °C was measured using a MR-compatible fiber-optic thermometer. MR imaging was performed by a 1.5-T scanner utilizing fast gradient echo sequences including a segmented echo planar imaging (seg-EPI) sequence for PRF and the following sequences for T 1 method: fast low-angle shot (FLASH), inversion recovery turbo flash (IRTF), saturation recovery turbo flash (SRTF), and true fast imaging (TRUFI). Temperature-induced change of the pixel values in circular regions of interest, selected on images under the temperature probe tip, was recorded. For each sequence, a calibration constant could be determined to be -0.0088 ± 0.0002 ppm °C(-1) (EPI), -1.15 ± 0.03 °C(-1) (FLASH), -1.49 ± 0.03 °C(-1) (IRTF), -1.21 ± 0.03 °C(-1) (SRTF), and -2.52 ± 0.12 °C(-1) (TRUFI). These constants were evaluated in further LITT experiments in phantom comparing the calculated temperatures with the fiber optic-measured ones; temperature precisions of 0.60 °C (EPI), 0.81 °C (FLASH), 1.85 °C (IRTF), 1.95 °C (SRTF), and 3.36 °C (TRUFI) were obtained. Furthermore, performing the Bland-Altman analysis, temperature accuracy was determined to be 0.23 °C (EPI), 0.31 °C (FLASH), 1.66 °C (IRTF), 1.19 °C (SRTF), and 3.20 °C (TRUFI). In conclusion, the seg-EPI sequence was found to be more convenient for MR temperature imaging of LITT due to its relatively high precision and accuracy. Among the T 1 method sequences, FLASH showed the highest accuracy and robustness.
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Hipertermia Inducida/métodos , Terapia por Láser/métodos , Imagen por Resonancia Magnética/métodos , Fantasmas de Imagen , Termografía/métodos , Animales , Tecnología de Fibra Óptica , Geles , Humanos , Hígado/cirugía , Neoplasias Hepáticas/secundario , Neoplasias Hepáticas/terapia , Imagen por Resonancia Magnética/estadística & datos numéricos , Modelos Biológicos , Sus scrofa , Temperatura , Termografía/estadística & datos numéricosRESUMEN
A methodology to determine the unknown shape of an embedded tumor is proposed. A functional that represents the mismatch between a measured experimental temperature profile, which may be obtained by infrared thermography at skin surface, and the solution of an appropriate boundary problem is defined. Using the Pennes's bioheat transfer equations, the temperature in a section of healthy tissue with a tumor region is modeled by a boundary problem. The functional is related to the shape of the tumor through the solution of the boundary problem, in such a way that finding the minimum of the functional form also means finding the unknown shape of the embedded tumor. The shape derivative of the functional is computed in each node of an approximation of the solution by the method of Finite Elements using similar methods considered by Pironneau [7]. The algorithm presented include an adaptive strategy to improve the error of the objective function. Numerical results with multiple connected tumors are considered to illustrate the potential of the proposed methodology.