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At least 361 records · Page 20Linked to original sources

PubMed1991

Quantitation of energy expenditure by infrared thermography.

The objective of this study was to adapt infrared thermography (IRT) to measure heat loss in human beings. IRT images were digitized and a mean body surface temperature was computed; heat losses caused by radiation, convection, and evaporation were calculated by using these data. Because subjects were standing during the procedure a small amount of heat was conducted through the feet; this heat was ignored. Total heat loss measured by IRT was not significantly different from values calculated from simultaneous indirect calorimetry (IC) determinations in fasting health subjects and in postsurgical patients receiving a constant infusion of energy. In healthy subjects, after eating the patterns of response to IRT and IC were as predicted from previous direct calorimetry data. Heat loss measured by IC increased first, 30 min postprandially, followed by an increase in heat loss at 60 min as measured by IRT. It was concluded that IRT as a noninvasive method can be used to quantitate heat loss in human beings.

Adult↗

PubMed2004

Seeing 'cool' and 'hot'--infrared thermography as a tool for non-invasive, high-throughput screening of Arabidopsis guard cell signalling mutants.

The use of Arabidopsis mutants defective in abscisic acid (ABA) perception has been instrumental in the understanding of stomatal function, in particular, ABA signalling in guard cells. The considerable attention devoted to ABA signalling in guard cells is due in part to (1) the fundamental role of ABA in drought stress and (2) the use of a screening protocol based on the sensitivity of seed germination to ABA. Such a screen has facilitated the isolation of ABA signalling mutants with genetic lesions that exert pleiotropic effects at the whole plant level. As such, there is a requirement for new approaches to complement the seed germination screen. The recent advances made in the use of infrared thermography as a non-invasive, high-throughput tool are reviewed here and the versatility of this technique for screening Arabidopsis defective in stomatal regulation is highlighted.

Abscisic Acid↗

PubMed2001

The analysis of sensitivity, specificity, positive predictive value and negative predictive value of cold provocation thermography in the objective diagnosis of the hand-arm vibration syndrome.

The diagnosis of digital artery vasospasm in the hand-arm vibration syndrome (HAVS) is clinically based, and the need for an accurate objective test to support the diagnosis has been highlighted. This study aims to analyse the potential of cold provocation thermography (CPT) to fulfill this role. CPT was performed on two groups of subjects: 10 controls and 21 patients with Raynaud's phenomenon (RP) secondary to HAVS. After taking a pre-cooling image, patients donned latex gloves and immersed their hands in water at a temperature of 5 degrees C for 1 min. The patients removed their hands from the water and discarded the gloves, and further images were taken every 30 s for 10 min. On each image, the temperatures of the tip and base were analysed for each digit. The sensitivity, specificity, positive and negative predictive values for fingertip temperatures only, fingertip and fingerbase temperatures combined, and fingertip temperature, fingerbase temperature and temperature gradient combined were determined. Patients with RP secondary to HAVS demonstrated significantly lower finger tip and base temperatures and lower digital temperature gradients at all time intervals when compared with controls (P < 0.01, Student's t-test). CPT has good sensitivity, specificity, positive predictive value and negative predictive value; it strongly supports the clinical diagnosis of digital vasospasm.

Adult↗

PubMed1996

The value of palpation, varicoscreen contact thermography and colour Doppler ultrasound in the diagnosis of varicocele.

Three non-invasive methods for the detection of a varicocele were evaluated in 63 men presenting with infertility. Physical examination, varicoscreen contact thermography and colour Doppler ultrasound were compared with spermatic venography as reference strategy. Physical examination had a sensitivity of 71%. Whether the non-palpable varicoceles are all subclinical is questionable since the specificity of physical examination was 69%. Varicoscreen proved be quick, easy and cheap but of no clinical value (sensitivity 97%, specificity 9%). Colour Doppler ultrasound using strict criteria was a good diagnostic tool (sensitivity 97%, specificity 94%). No imaging difference was seen with colour Doppler ultrasound among clinical and subclinical varicoceles. Since the debate on treating all degrees of varicocoeles is ongoing, we suggest that Doppler sonography should be a routine examination in infertile men.

Humans↗

PubMed1981

Thermography in the assessment of peripheral joint inflammation--a re-evaluation.

The reproducibility and sensitivity of quantitative infra-red thermography as a measure of peripheral joint inflammation was reassessed. Experiments were carried out in a temperature-controlled room at 20 degrees C. Initial stabilization experiments showed that in normal, medium sized, joints, there was an initial rapid cooling phase followed by a slower cooling phase which lasted longer than two hours. In the knees the differences between normal and active rheumatoid joints increased the longer patients remained in the room but for practical reasons a 30-minute stabilization period was subsequently chosen. In views of hands and fingers, rebound increases in skin temperature after entering the room, together with lesser differences between inflamed and non-inflamed joints, were found. The results suggested that the thermographic technique examined was adequate for detecting inflammatory changes in knee, ankles and elbows but unsatisfactory for quantification of inflammation in the small joints of the hands.

Adult↗

PubMed1987

Microwave thermography--an index of inflammatory joint disease.

Microwave thermography is a technique measuring microwave emission from sites of inflammation. Microwaves have a wavelength of around 10 cm and are therefore able to penetrate clinically useful depths of up to 4 cm directly measuring tissue thermal radiation. A microwave detector was applied to the study of joint inflammation in rheumatoid arthritis and in a normal control group. Fifty-two knees were scanned using the detector and a microwave thermographic index was calculated for each knee. A strong correlation was found between the microwave thermographic index, and the clinical and laboratory parameters measured. This technique was found to be reproducible, quick, simple to use at the bedside without a controlled environment and, since it measures internally emitted radiation, is inherently safe.

Arthritis, Rheumatoid↗

PubMed1990

The use of infra-red thermography in a rheumatology unit.

Infra-red thermography is a technique that is under-used in rheumatology; one reason is the supposed necessity for a temperature-controlled room in which to conduct tests. The results of a series of cold challenges to the hand, repeated on a normal subject in a temperature-controlled room and in other parts of a rheumatology ward, show very good reproducibility outside the temperature-controlled room, provided that the immediate environment is draught-free.

Humans↗

PubMed1994

Measurement of the skin temperature at the entry wound by means of infrared thermography. An investigation involving the use of .22- to .38- caliber handguns.

This study examines the temperatures at the point that bullets impact human skin. With the assistance of infrared thermography, measurements were taken after shots were fired by .22-, .25-, .32-, .38-special-caliber, and 9-mm Luger pistols and revolvers. The highest temperature readings at the entry point were recorded with the .22 caliber and the lowest with the .32 caliber. The measurement of projectile temperatures in flight resulted in readings of 147 degrees-152 degrees C for the 9-mm Luger.

Humans↗

PubMed1996

Validation of thermography in the diagnosis of reflex sympathetic dystrophy.

OBJECTIVES: To examine the validity of several thermogram-derived indices of autonomic functioning in the diagnosis of reflex sympathetic dystrophy (RSD). DESIGN: A series of chronic pain patients were classified diagnostically based on thermogram results using discriminant function analysis, and validity measures (e.g., sensitivity, specificity) were used to determine the accuracy of computerized thermographic pixel analysis in discriminating RSD from other pathology. SETTING: The study was conducted at the Rush Pain Center, a multidisciplinary outpatient pain clinic. PATIENTS: A series of 46 chronic pain patients referred for suspected sympathetically mediated pain. INTERVENTIONS: All patients underwent computerized thermographic examination under a baseline condition after acclimating to a climate-controlled room, immediately after a cold challenge was applied to the contralateral uninvolved extremity (4 degrees C for 90 s) and 20 min after the cold challenge. OUTCOME MEASURES: Temperature during the three experimental periods, degree of temperature asymmetry between affected and nonaffected limbs during the three periods, response to cold challenge, and recovery following cold challenge were measured. RESULTS: Temperature asymmetry accurately discriminated between RSD and non-RSD patients, with the most accurate asymmetry measures obtained at baseline. Responses to cold challenge and actual temperature values did not discriminate between RSD and non-RSD pain patients. CONCLUSIONS: Thermography can be a useful component of RSD diagnosis. In situations where sensitivity and specificity are equally important, an asymmetry cutoff of 0.6 degree C appears optimal. If specificity (i.e., accurately ruling out non-RSD cases) is more important, a cutoff of 0.8 degree C or 1.0 degree C may be considered as well.

Adult↗

PubMedDate not supplied

Critical evaluation of the use of thermography in the investigation of scintigraphically cold thyroid nodules.

One hundred and fifty-five cases of scintigraphically "cold" thyroid nodules were examined telethermographically to determine their thermal gradient. All nodules hyperthermic greater than or equal to 1.5 degrees C were successively removed, as were those (regardless of the thermal gradient) present in men, those in women younger than 21 years and older than 45 years of age, and those clinically suspect, the latter regardless of age or sex of the patient. Of 95 operated cases, 79 proved to be benign or nontumoral nodules, and 16 were carcinomas at histology. Hyperthermia greater than or equal to 1.5 degrees C had been present in 43% of the benign cases and in only 25% of the carcinomas. Out of ten cases were hyperthermia greater than or equal to 2 degrees C, none was a carcinoma. A malignancy was found in 26% of 23 normothermic cases, 17.6% of 34 slightly hyperthermic cases, and only 10.5% of 38 markedly hyperthermic (greater than or equal to 1.5 degrees C) cases. There was no evident correlation between the thermal gradient and the clinical diameter of the thyroid nodule. Our study affirms that thermography is not reliable when used to select cold thyroid nodules for surgical removal.

Adolescent↗

PubMed1993

Potential applications of ocular thermography.

Thermography is an investigative technique which allows rapid color-coded display of the temperature across a wide surface by means of infrared detection. We describe an ocular thermographic study of a normal population and present case studies describing the application of this technique for patients with ocular disease. We found that 95% of the normal population have an interocular temperature difference (temperature of center of right cornea minus temperature of center of left cornea) of 0.60 degrees or less. There appears to be a greater difference in temperature between the limbus and the center of the cornea in patients with dry eyes. This technique has potential for evaluating tear film disorders and inflammatory conditions, for monitoring the progress of such conditions, and for evaluating the efficacy of various treatments.

Acanthamoeba Keratitis↗

PubMed1985

Thermography as a predictive tool for laser treatment of port-wine stains.

The argon laser, which has been proven both useful and safe for port-wine stain therapy, interacts with the hemoglobin of the vessels. In a percentage of cases, this treatment is still inefficient, and there is a lack of correlation between these bad results and clinical or histologic criteria. Thermography, which explores the vascularization of the port-wine stain, leads us to consider port-wine stains from a physical point of view. This very simple test shows no correlation with the clinical parameters of port-wine stain but is closely related to the results obtained with laser therapy. It seems to be a good criterion to estimate the argon laser treatment prognosis.

Adolescent↗

PubMed1986

The evaluation of liquid crystal thermography in the investigation of nerve root compression due to lumbosacral lateral spinal stenosis.

The role of liquid crystal thermography (LCT) in the investigation of nerve root compression due to lumbosacral lateral spinal stenosis was evaluated using a quantitative analysis technique. In 28 healthy volunteers, normal lower limb dermatomal asymmetry was found to follow a Gaussian distribution, with a normal range of less than 1.0 degree for the lower limbs and less than 1.9 degrees for the feet. The results of LCT from a patient group were compared with those from other investigations, with the following results: clinical assessment (107 patients), 53% agreement; myelography (60 patients), 45% agreement; computerized tomography (35 patients), 46% agreement; electromyography (27 patients), 41% agreement; and surgical findings (19 patients), 53% agreement. Each method of investigation was compared against the surgeon's final overall assessment. Clinical assessment agreed in 76%, myelography in 71%, computerized tomography in 71%, and electromyography in 70%. However, agreement could be demonstrated in only 48% of cases using LCT; therefore, it would appear that LCT is by far the least reliable of these techniques in the diagnosis of nerve root compression.

Body Temperature↗

PubMed2001

Freezing of barley studied by infrared video thermography.

Freezing of barley (Hordeum vulgare), Hordeum murinum, and Holcus lanatus was studied using infrared video thermography. In the field, ice could enter H. lanatus leaves through hydathodes. In laboratory tests with barley, initially 0.4% of the leaf water froze, spreading in alternate strips of high and low freezing intensity longitudinally at 1 to 4 cm s(-1), and simultaneously spreading laterally at 0.3 cm s(-1). Similar results were obtained in the field with H. lanatus. A distinct second, more intense, freezing event spread slowly from the margins of the leaves toward the midrib. Organs of uprooted barley tested in the laboratory froze in this order: nucleated leaf, roots, older leaves, younger leaves, and secondary tillers. When ice spread from one leaf to the rest of the plant the crown delayed spread to the roots and other leaves. There was a longer delay above than below -2 degrees C, helping to protect the crown from freezing during mild frosts. Initial spread of freezing was not damaging. However, the initial spread is a prerequisite for the second freezing event, which can cause damage. The route of the initial spread of ice may be extracellular, drawing water from more gel-like parts of the cell wall.

Freezing↗

PubMed2004

A novel method to prevent secondary exposure of medical and rescue personnel to toxic materials under biochemical hazard conditions using microwave radar and infrared thermography.

In order to prevent secondary exposure of medical personnel to toxic materials under biochemical hazard conditions, we performed a noncontact determination of exposure to toxic conditions via 1215-MHz microwave radar and thermography. A toxic condition was induced by intravenous administration of lipopolysaccharide (LPS) in rabbits. The exposure to LPS was determined by linear discriminant analysis using non-contact derived variables.

Animals↗

PubMed1980

Doppler flow studies, venography and thermography in the evaluation of varicoceles of fertile and subfertile men.

The varicoceles of 39 men of proven fertility and 57 husbands of infertile marriages were assessed by the Doppler technique and classified according to venous activity. Retrograde left renal venography in 17 subjects showed that Doppler grading was unable to distinguish between 7 patients with competent internal spermatic veins and 10 with internal spermatic vein reflux. Patients whose varicoceles were associated with internal spermatic vein reflux had a significant reduction in sperm density and these may be implicated as a cause of male infertility. The remaining varicoceles were probably the result of incompetence of other venous tributaries of the spermatic cord and were associated with higher sperm densities. The Doppler was able to identify accurately those varicoceles with significant elevation of scrotal temperature as determined by computer assisted infra-red scrotal thermography. The sperm densities of these patients were similar to the values found in patients with normal scrotal temperatures. The varicoceles of infertile men were found to have a greater incidence of spontaneous venous activity than the varicoceles of fertile men and this suggests that any reduction of fertility caused by elevation of scrotal temperature may be via an effect other than a reduction in sperm density.

Adult↗

PubMedDate not supplied

Thermography of malignant melanomas.

Thermography is investigated as a tool for the diagnosis of malignant melanoma. A correlation between hyperthermia and malignancy is demonstrated in about two-thirds of the cases examined.

Humans↗

PubMed1981

Liquid-crystal thermography in determining the lateral extents of basal-cell carcinomas.

Liquid-crystal thermography is a rapid, noninvasive, inexpensive method for determining the lateral extents of certain cutaneous malignancies. This report describes the technique as it is applied to basal-cell carcinomas. Results indicate that it is useful for neoplasms of moderate to heavy cellular density but little help in outlining neoplasms of low cellular density like morpheaform basal-cell carcinomas.

Aged↗