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At least 343 records · Page 19Linked to original sources

PubMed2004

Infrared thermography: a rapid, portable, and accurate technique to detect experimental pneumothorax.

RATIONALE AND OBJECTIVE: Pneumothorax (Ptx) is a life-threatening complication that can result from trauma, mechanical ventilation, and invasive procedures. Infrared thermography (IRT), a compact and portable technology, has become highly sensitive. We hypothesized that IRT could detect Ptx by identifying associated changes in skin temperature. MATERIALS AND METHODS: Bilateral nonpenetrating chest incisions or needle punctures were performed in 21 anesthetized rats. Rats were then randomized to no, bilateral, left, or right Ptx by either open (n = 16) or closed percutaneous (n = 5) puncture through selected pleurae. Real-time thermographic images and surface temperature data were acquired with a noncooled infrared camera. RESULTS: In all cases, blinded observers correctly identified each Ptx with real-time grayscale image analysis. When compared to either the ipsilateral baseline or an abdominal reference, experimental Ptx produced a significantly greater decrease in surface temperature when compared to non-Ptx control. CONCLUSIONS: These results demonstrate that portable infrared imaging can rapidly and accurately detect changes in thoracic surface temperature associated with experimental pneumothorax.

Animals↗

PubMed2006

Development and testing of a wearable Integrated Thermometer sensor for skin contact thermography.

The need of wearable devices for the thermal monitoring is rising. These devices could be used during medical continuous monitoring, for instance in breast cancer investigation, or for the monitoring of vascular, dermatological and rheumatic disorders, in viability studies, and during physical exercises. We had designed and constructed a wearable device for skin-contact thermography that uses integrated silicon sensors. The bench test validation was performed by means of a commercial oven for the static bench test and a properly designed phantom for the dynamic bench test. The thermal resolution was better than 0.03 degrees C and the spatial resolution equal to 1.6 x 10(-5)m2. We then investigated its performance in a medical application, suited for clinical testing, in which volunteers were subject to a maximal rate of thermal skin variation equal to 3.1 degrees C/0.25 h. We also compared the results with those obtained by means of an Infrared-Digital-Video-Camera. Results of the comparison showed a maximal error always lower than 0.14 degrees C.

Equipment Design↗

PubMed2006

A dynamical model of subharmonic generation in ultrasonic infrared thermography.

Subharmonics are often observed in ultrasonic infrared thermography (UIR) system as samples are excited by ultrasonic transducers, and it is testified that, as the subharmonics appear, the detectability of cracks or defects in the sample is greatly enhanced in the UIR system. A dynamical model to explore the generation mechanism of the subharmonics and simulate the sample motion excited by an ultrasonic transducer in the UIR system is presented in this paper. In the model, the sample is continuously impacted by the transducer as the transducer is pushed to the sample by a constant force, in which the sample is simplified as a damped oscillator and the transducer is simplified as an active oscillator with constant frequency and amplitude. The impact process is also taken into account, in which the acting force is assumed to vary linearly during the impact process. A stable waveform of subharmonics in the sample can be obtained in appropriate conditions.

Algorithms↗

PubMed2003

Comparison of thermography and laser Doppler imaging in the assessment of Raynaud's phenomenon.

The main objective of the study was to compare the techniques of thermographic and laser Doppler imaging in the assessment of digital blood flow. Thermography measures surface temperature; laser Doppler measures microciculatory flow. Seventeen healthy control subjects and 40 patients with Raynaud's phenomenon (7 primary, 33 secondary to systemic sclerosis) underwent a 20-min acclimatization period at 23 degrees C. Thermographic and then laser Doppler images were taken of the dorsal aspect of both hands, and the procedure was repeated at a room temperature of 30 degrees C. Three regions/values of interest from each hand were chosen for analysis: the dorsum of the hand, the tip of the middle finger, and the "gradient" between these. Thermographic and laser Doppler results correlated poorly. For example, correlations between techniques for the gradient value were as follows: left hand 23 degrees C, r = 0.61; right hand 23 degrees C, r = 0.64; left hand 30 degrees C, r = 0.47; right hand 30 degrees C, r = 0.48. One explanation for these findings is that laser Doppler imaging is more sensitive to blood flow changes and therefore more likely to show inhomogeneities than the highly damped temperature response. Therefore one technique cannot substitute for another.

Blood Flow Velocity↗

PubMed2003

Infrared thermography and thermocouple mapping of radiofrequency renal ablation to assess treatment adequacy and ablation margins.

OBJECTIVES: The primary disadvantage of renal tumor RF ablation is the inability to monitor the intraoperative propagation of the RF lesion with real-time imaging. We sought to assess whether adequately lethal temperatures are obtained at the margins of the intended ablation zone using laparoscopic thermography to monitor radiofrequency (RF) lesions in real time, thermocouple measurements, and histopathologic evaluation. METHODS: Renal RF lesions were created under direct laparoscopic vision in the upper (1 cm diameter) and lower (2 cm) poles of the right kidney in 5 female pigs. The RF lesions were produced with the RITA generator and probe, set at 105 degrees C for 5-minute ablations. During RF treatment, a laparoscopic infrared (IR) camera measured the surface parenchymal temperatures, as did multiple thermocouples. The pigs were then either immediately killed (n = 3) or allowed to live for 2 weeks (n = 2). The kidneys were removed to correlate the temperature measurements with histologic analysis of the ablated lesion. RESULTS: Using a threshold temperature of greater than 70 degrees C for visual "temperature" color change, the IR camera identified the region of pathologic necrosis of the renal parenchyma during RF ablation. Thermocouple measurements demonstrated that the temperatures at the intended ablation radius reached 77.5 degrees C at the renal surface and 83.7 degrees C centrally, and temperatures 5 mm beyond the set radius reached 52.6 degrees C at the surface and 47.7 degrees C centrally. The average diameter of the gross lesion on the surface of the kidney measured 17.1 mm and 22.4 mm for 1-cm and 2-cm ablations, respectively. These surface measurements correlated with an average diameter of 16.1 mm and 15.9 mm (1-cm and 2-cm ablations, respectively) as measured with the IR camera. All cells within these ablation zones were nonviable by nicotinamide adenine dinucleotide diaphorase analysis. The average depth of the lesions measured 19 mm (1-cm ablation) and 25 mm (2-cm ablation) on gross histologic examination. CONCLUSIONS: The laparoscopic IR camera is able to monitor the surface renal temperatures during RF treatment. Thermocouple measurements during RF ablation confirmed the thermographic findings and demonstrated that lethal temperatures at the margin of the intended treatment zone are routinely obtained and that a rapid decline in temperature occurs beyond the predicted ablation margin.

Animals↗

PubMed1999

Dilatation of subcutaneous perforating blood vessels associated with capsaicin-induced cutaneous axon reflex: demonstration with subtraction thermography.

The axon reflex induced by intracutaneous application of capsaicin to the forearm of human subjects and the back of anesthetized rats pretreated with intravenous injection of Evans blue was investigated using sequential subtraction thermography. In the human experiment, thermograms showed an immediate and general temperature decrease after capsaicin injection. Four min after application, several spotty areas with a temperature increase ('hot spots') appeared within and outside of the flare caused by capsaicin-induced axon reflex. A vascular murmur was observed on ultrasonic Doppler flowscopy at the hot spots. In the rat experiment, two hot spots appeared, one cranial to and one caudal to the site of injection, within different dermatomes. Hot spots appeared in rats with the pretreatment of intravenous hexamethonium and surgical removal of the bilateral lumbar paravertebral sympathetic trunks. Postmortem examination of the rats revealed that these hot spots coincided with perforating blood vessels. It was suggested that hot spots in the axon reflex identified by subtraction thermograms are induced by a passive dilatation of perforating vessels which supply blood to the flare.

Adult↗

PubMed1995

Infrared thermography of the tear film in dry eye.

Infrared ocular thermograms were recorded for a group of 36 dry eye patients and for 27 age- and sex-matched controls. Mean ocular surface temperature was greater in the dry eye group (32.38 +/- 0.69 degrees C) compared with the control group (31.94 +/- 0.54 degrees C; p < 0.01). In addition, there was a greater variation of temperatures across the ocular surface in the dry eye group, illustrated by the difference in temperature between the limbus and the centre of the cornea (0.64 +/- 0.20 degrees C in dry eye patients compared with 0.41 +/- 0.20 degrees C in the control group; p < 0.001). This parameter was also shown to be greater in dry eye patients who displayed either a fast tear break-up time or a poor Schirmer's test result. Infrared thermography is a non-invasive and objective technique that may prove a useful research tool for study of the tear film, its deficiencies and its various treatment modalities.

Adult↗

PubMed1996

Electronic infrared thermography as a dental research technique.

Electronic infrared thermography is an imaging modality for the accurate quantification of surface temperature. It has been used in medicine since the 1960s but its use in dentistry has been limited. Its use in dentistry could, however, be very useful, for example in objectively quantifying post-surgical inflammation and studying the effects of treatment with agents such as analgesics and anti-inflammatory drugs.

Adult↗

PubMed2005

[Digital X-ray mammography: comparison of the image quality achievable with a wet laser imager, a dry infrared laser imager and a dry laser imager using direct thermography].

PURPOSE: To compare the image quality of digital X-ray mammographies obtained with wet imagers with that of standard dry imaging technology. MATERIAL AND METHODS: Beginning 03/08/2003, 200 X-ray mammographies with a digital fullfield mammography system (Lorad Selenia, Lorad/Hologic) were prospectively and consecutively documented with a wet laser imager (Scopix LR 5200, Agfa), a dry infrared laser imager (DryView 8610, Kodak) and a dry imager using the principle of direct thermography (Drystar 4500M, Agfa, N = 166). One X-ray exposure was systematically chosen from each examination and was presented in an anonymous and randomized form to three radiologists who evaluated the films using a structured questionnaire. RESULTS: The visualization of normal anatomic structures was considered being good to excellent for all imagers with the mean assessments 1.0 - 2.4 for the Drystar 4500M, 1.0 - 2.1 for the DryView 8610 and 1.1 - 2.0 for the Scopix LR 5200. The mean assessments were 0.1 - 0.6 points lower in dense than in normal parenchyma, thus, the parenchymal density is the predominant factor for image quality. CONCLUSION: In view of the comparable image quality obtained with the different imagers used in the study, individual decisions to purchase a specific imager will be based on economics rather than on diagnostic points of view.

Computer Peripherals↗

PubMed1984

The value of thermography in the early diagnosis of postoperative sternal wound infections.

Peristernal skin temperatures were recorded postoperatively by infrared thermography in 150 patients. Persistent elevation of peristernal skin temperature during the 3rd and 4th post-operative week was found in 5 patients, all of whom developed sternal wound infection. A further group of 18 patients, all suspected to have occult wound infection, showed persistent temperature elevation in 7 patients, 6 of these patients were proven later to have manifest infection and needed treatment. Close thermographic scruting of the incision in patients with suspected but not proven infection appears to be useful in deleting early stages of deep seated infections.

Cardiac Surgical Procedures↗

PubMed1988

[The value of thermography in the diagnosis of breast cancer and in the selection of risk groups].

Within the framework of a prospective screening study for breast cancer, mammographic and thermographic examinations were performed in 11546 clinically asymptomatic women between 1973 and 1980. Until 1986, breast cancer was diagnosed in 141 women. Conforming with the literatur we demonstrate that the accuracy of thermography declines with decreasing tumour size (pTis 27%, pT1 33.3%, pT2 64%). The rate of breast cancer incidence in women with at least one thermogram considered suspicious or requiring further investigation was 2.7 +/- 0.4 during a period of up to 12 years. This value is not higher than that of many other risk factors and lies clearly below the factor of familial predisposition.

Adult↗

PubMed1987

[The importance of thermography in the diagnosis of lumbar radicular pain syndromes].

This study proved the existence of lateral differences in thermographic recordings of the legs of 83 out of a total of 84 patients with the clinical diagnosis "lumbar disk herniation". In 68.5 per cent only of 71 patients with unilateral symptoms, however, the hypothermic areas occurred in the symptomatic leg. These areas could not be matched with corresponding dermatomas. As regards determination of the level of the herniation, thermography is an unreliable method for differentiation between the different segments, because the site of the dermatoma cannot be identified in relation to the site of the herniation. The mechanism of difference in temperature distribution probably depends on sympathetic reflexes with increased activity in the vasoconstrictor system due to pain. These reflexes are not limited to one dermatoma. This has been confirmed by means of diagnostic nerve blocks of the appropriate root.

Adult↗

PubMed1986

[Non-invasive imaging procedures in the diagnosis and control of therapy of varicoceles. 2. Importance of thermography and sonography for therapy control following sclerotherapy of varicoceles].

In 41 patients with varicoceles, a combined thermographic and sonographic examination of the scrotum was carried out pretherapeutically as well as 14 days and 3 months after percutaneous sclerotherapy. In the differentiation of a successful sclerosing or a varicocele persistence, thermography shows a higher sensitivity than sonography with 34 posttherapeutic normal findings and 7 persisting hyperthermias. The sonographic sign of a successful varicosclerosation is the absence of venous dilation of the pampiniform plexus in an upright position with Valsalva's manoeuvre in 36 patients. After proximal sclerosing of the testicular vein sonography reveals a reduction in vascular size; thrombosed veins of the pampiniform plexus are demonstrated only after distal sclerosing. There are no sonographically detectable disorders of the testes after varicosclerosation. Thermographic and sonographic control after percutaneous sclerotherapy or surgical ligation of varicoceles is indicated in children and in doubtful clinical or spermatological cases.

Adolescent↗

PubMed1992

[Gustatory sweating demonstrated by infrared thermography].

A 35-year-old man, previously healthy except for a grade 1 goitre, sustained a spontaneous left pneumothorax treated with a Bülau drain. When the left pneumothorax recurred 2 months later a left thoracotomy was performed. Two bullae at the lung apex were resected and a pleurodesis performed. After the operation the patient noted hypaesthesia of the dorsum of the left upper arm, mild ptosis of the left eyelid as well as reduced sweat secretion over the left half of the face and the left rib cage. The hypaesthesia improved, but the sympathetic nerve deficits remained. There were no other neurological signs. 9 months later, within one minute of eating a sour apple, the patient developed severe sweating over the left half of the face and the left chest. The reaction was confirmed by infra-red thermography which proved that the skin temperature in the sweating region had fallen to 3 degrees C. The likely cause of localized gustatory sweating is intra-operative damage of the stellate ganglion or its preganglionic nerve connections. Treatment is limited to avoidance of the precipitating gustatory stimulus.

Adult↗

PubMed1976

Lack of efficacy of thermography as a screening tool for minimal and stage I breast cancer.

In a study of thermograms of 42 patients with Stage 1 or smaller carcinomas of the breast, 44 confounding cases and 64 randomly selected subjects being screened, we found that the ability of expert thermographers to identify the patients with carcinoma correctly (true positive = 0.238) varied little from the ability of untrained readers (true positive = 0.301). Furthermore, in the expert group, the indexes of suspicion were so high (0.436) and the true-positive levels were so relatively low (0.238, P = 0.0005) that thermography may well have a very limited role as a screening or pre-screening modality for the detection of minimal or Stage 1 breast cancers.

Breast Neoplasms↗

PubMed1991

Facial thermography, basis, protocol, and clinical value.

Computerized electronic telethermography provides clinicians with a reliable evaluation of subtle body surface temperature changes that show underlying physical disorders characterized by pain. The first study population involved 4000 measurements of 100 volunteers at the Medical School of New Jersey. This study of normal volunteers evaluates the validity and reliability of using 0.5 degrees C skin surface temperature difference between opposite sides of the head as a minimum difference standard for recognition of a clinically significant thermographic abnormality. A second study population of over 300 patients with clinically suspected temporomandibular disorder were used. The authors used a standard thermographic protocol procedure that is approved by the Academy of Neuromuscular Thermography. Also discussed in detail are artifactual influences and trigger point detection. The clinical value of this information in the diagnosis and treatment of temporomandibular disorder patients is self evident.

Adult↗

PubMed1979

Centimeter- and millimeter-wave thermography--a survey on tumor detection.

Thermography at centimeter and millimeter wavelengths can measure subsurface temperatures of the human body. Radiative and bio-heat transfer influence the wavelength dependent subcutaneous temperature and spatial resolution. Recent clinical results in treatment monitoring of arthritis, detection of tumors in the neck and brain area, and breast cancer are reviewed.

Adult↗

PubMed1983

Introduction to correlation microwave thermography.

Correlation microwave thermography, a new process based on a coherent detection of noise, is able to improve the localization of the thermal gradients in the tissues. We explain the principles of this method and describe the first system which has been built and tested. Several experiments point out that with this process better spatial resolution and flexibility can be expected.

Microwaves↗