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At least 343 records · Page 19Linked to original sources
PubMed1995

Tympanic versus rectal thermometry in pregnant women.

OBJECTIVE: To assess the accuracy of the tympanic membrane thermometer for use with pregnant women. DESIGN: Cross-sectional descriptive study. SETTING: A major medical center in the midwestern United States. PARTICIPANTS: Thirty-three hospitalized, afebrile pregnant women. MAIN OUTCOME MEASURES: Tympanic membrane thermometers and glass mercury thermometers were used to measure body temperature at the ear and rectum, respectively. The results were compared using two statistical methods: the Pearson correlation coefficient and a new technique suggested by Bland and Altman (1986). RESULTS: Auditory canal temperature measured by a tympanic membrane thermometer correlated with rectal temperature as measured by a glass mercury thermometer (r = 0.38, p = 0.01). Thus, the tympanic membrane thermometer is acceptable for monitoring the body temperature of pregnant women. However, the device's estimation of rectal temperature is not clinically reliable. CONCLUSIONS: Tympanic membrane thermometers, when applied with direct measures, are acceptable for use with pregnant women. It is not recommended that the rectal estimate mode be used with pregnant women.

Body Temperature↗
PubMed2002

Particle image velocimetry and thermometry for two-phase flow problems.

Image processing in fluid mechanics has become an important quantitative tool for flow analysis. The feasibility of simultaneous measurements of instantaneous velocity and temperature fields, as well as for tracking interfaces, creates a functional tool to describe thermally driven flows accompanied by phase change. The information thus gathered is essential for the verification and validation of computation models. The paper reviews the image processing methods developed by the author and his coworkers to analyze typical problems of two-phase flow. Simultaneous measurement of temperature and velocity fields, obtained by using liquid crystal tracers, are applied to elucidate solidification and growing vapor bubble problems.

Convection↗
PubMed1978

Limb skin thermometry in racehorses.

Skin temperature measurements were recorded of the legs of 13 racehorses between 2 and 5 years old. The normal limb temperature patterns are described. In over 90 per cent of the normal horses the difference between contralateral limbs was less than 1 degree C, but in the remainder differences of up to 8 degree C were recorded due to the excessive cooling of one limb. One horse had a constant temperature elevation of one foreleg, but it remained in training for 7 weeks without any obvious ill effects. Because of the small numbers of horses in the survey and their freedom from tendon injuries it was not possible to draw any conclusions about the efficacy of thermometric screening in the early diagnosis of tendon injuries.

Animals↗
PubMed2004

Transurethral ultrasound applicators with directional heating patterns for prostate thermal therapy: in vivo evaluation using magnetic resonance thermometry.

A catheter-based transurethral ultrasound applicator with angularly directional heating patterns has been designed for prostate thermal therapy and evaluated in canine prostate in vivo using MRI to monitor and assess performance. The ultrasound transducer array (3.5 mm diameter tubular transducers, 180 degrees active sectors, approximately 7.5 MHz) was integrated to a flexible delivery catheter (4 mm OD), and encapsulated within an expandable balloon (35 mm x 10 mm OD, 80 ml min(-1) ambient water) for coupling and cooling of the prostatic urethra. These devices were used to thermally coagulate targeted portions of the canine prostate (n = 2) while using MR thermal imaging (MRTI) to monitor the therapy. MRI was also used for target definition, positioning of the applicator, and evaluation of target viability post-therapy. MRTI was based upon the complex phase-difference mapping technique using an interleaved gradient echo-planar imaging sequence with lipid suppression. MRTI derived temperature distributions, thermal dose exposures, T1-contrast enhanced MR images, and histology of sectioned prostates were used to define destroyed tissue zones and characterize the three-dimensional heating patterns. The ultrasound applicators produced approximately 180 degrees directed zones of thermal coagulation within targeted tissue which extended 15-20 mm radially to the outer boundary of the prostate within 15 min. Transducer activation lengths of 17 mm and 24 mm produced contiguous zones of coagulation extending axially approximately 18 mm and approximately 25 mm from base to apex, respectively. Peak temperatures around 90 degrees C were measured, with approximately 50 degrees C-52 degrees C corresponding to outer boundary t43 = 240 min at approximately 15 min treatment time. These devices are MRI compatible, and when coupled with multiplanar MRTI provide a means for selectively controlling the length and sector angle of therapeutic thermal treatment in the prostate.

Animals↗
PubMed1996

1H MRI phase thermometry in vivo in canine brain, muscle, and tumor tissue.

The temperature sensitivity of the chemical shift of water (approximately 0.01 ppm/degree C) provides a potential method to monitor temperature changes in vivo or in vitro through the changes in phase of a gradient-echo magnetic resonance (MR) image. This relation was studied at 1.5 T in gel materials and in vivo in canine brain and muscle tissue, heated with a radio frequency (rf) annular phased array hyperthermia antenna. The rf fields associated with heating (130 MHz) and imaging (64 MHz) were decoupled using bandpass filters providing isolation in excess of 100 dB, thus allowing simultaneous imaging and rf heating without deterioration of the MR image signal-to-noise ratio. In a gel, temperature sensitivity of the MR image phase was observed to be (4.41 +/- 0.02) phase degrees/degree C for Te = 20 ms, which allowed temperature changes of 0.22 degree C to be resolved for a 50-mm3 region in less than 10 s of data acquisition. In vivo, for Te = 20 ms, the temperature sensitivity was (3.2 +/- 0.1) phase degrees/degree C for brain tissue, (3.1 +/- 0.1) phase degrees/degree C for muscle, and (3.0 +/- 0.2) phase degrees/degree C for a muscle tumor (sarcoma), allowing temperature changes of 0.6 degree C to be resolved in a 16-mm3 volume in less than 10 s of data acquisition. We conclude that, while the technique is very sensitive to magnetic field inhomogeneity, stability, and subject motion, it appears to be useful for in vivo temperature change measurement.

Animals↗
PubMed1996

Mg/Ca Thermometry in Coral Skeletons

The magnesium-to-calcium (Mg/Ca) ratio of coral skeletons from Ishigaki Island, Ryukyu Islands, Japan, closely tracked sea surface temperature (SST) over an 8-year period. Measurements were made with the fast technique of inductively coupled plasma-atomic emission spectrometry. The variation of the coral Mg/Ca ratio with SST change is about four times that of the current, widely used coral strontium-to-calcium ratio. The temporal and geographic variation of the seawater Mg2+/Ca2+ ratio probably has little influence on coral Mg/Ca variation. Results indicate that the coral Mg/Ca ratio has the potential to provide fast, precise, high-resolution proxies for past tropical SSTs.

Journal Article↗
PubMed2006

Thermometry in paediatric practice.

Body temperature is commonly measured to confirm the presence or absence of fever. However, there remains considerable controversy regarding the most appropriate thermometer and the best anatomical site for temperature measurement. Core temperature is generally defined as the temperature measured within the pulmonary artery. Other standard core temperature monitoring sites (distal oesophagus, bladder, and nasopharynx) are accurate to within 0.1-0.2 degrees C of core temperature and are useful surrogates for deep body temperature. However, as deep-tissue measurement sites are clinically inaccessible, physicians have utilised other sites to monitor body temperature including the axilla, skin, under the tongue, rectum, and tympanic membrane. Recent studies have shown that tympanic temperature accurately reflects pulmonary artery temperature, even when body temperature is changing rapidly. Once outstanding issues are addressed, the tympanic site is likely to become the gold standard for measuring temperature in children.

Axilla↗
PubMed1996

Corneal temperature in patients with dry eye evaluated by infrared radiation thermometry.

AIMS: The corneal temperature change following each blink was investigated in patients with dry eye using an infrared radiation thermometer. METHODS: Twenty patients with dry eye and 20 normal controls were enrolled in this study. Subjects kept their eyes open for 10 seconds without blinking and corneal temperature was measured every second with a recently improved infrared radiation thermometer. RESULTS: In the 20 patients with dry eye, corneal temperature change after keeping the eye open for 10 seconds was 0.21 (SD 0.06) degree C while it was 0.61 (0.28) degree C in the 20 normal patients (p = 0.0001). In an exponential equation, the inclination of the slope of a patient with dry eye was smaller than the normal. The correlation coefficient was r = 0.79 (0.16) in patients with dry eye and r = 0.90 (0.07) in normal patients. The mean K value of patients with dry eye was 0.20 (0.13)/second and that of normal subjects was 0.31 (0.19)/second (p = 0.03). CONCLUSION: Findings demonstrate the usefulness of this thermometer for measuring corneal temperature in the evaluation of dry eye. Decrease in corneal temperature with each blink in patients with dry eye was smaller than in normal subjects.

Adolescent↗
PubMed1997

An evaluation of infra-red tympanic thermometry for thermal physiology research.

This study forms part of a research programme to investigate the relationships between the rise in core temperature and the environmental temperature in soldiers exercising at a constant rate. The measurement of core temperature is a fundamental requirement for this research. The aim of this study was to evaluate the use of an infra-red tympanic thermometer (IVAC Corecheck) for use in thermal physiological studies conducted outside the laboratory environment by comparing the right ear temperature by TM thermometer and the left ear external auditory meatus by thermistor. The slope of the regression line between the two measurements was 0.9967 with a correlation coefficient of 0.706 which is reasonable. The TM thermometer in general reads higher than the aural thermometer with a 95% confidence limit for agreement from +0.78 to -0.53 degrees C of the aural temperature. Thus this study demonstrated that the tympanic thermometer (IVAC Corecheck) is sufficiently reliable compared to the aural thermistor to justify field trials.

Body Temperature↗
PubMed2000

Prostate cancer: MR imaging and thermometry during microwave thermal ablation-initial experience.

Percutaneous interstitial microwave thermoablation of locally recurrent prostate carcinoma was continually guided with magnetic resonance (MR) imaging. Phase images and data were obtained with a rapid gradient-echo technique and were used to derive tissue temperature change on the basis of proton-resonance shift. Thermally devitalized regions correlated well with the phase image findings. MR imaging-derived temperatures were linearly related to the fluoroptic tissue temperatures. MR imaging can be used to guide thermoablation.

Aged↗
PubMed1993

Tissue thermometry during ultrasound exposure.

In order to quantify ultrasound therapy it is important to measure the tissue temperature during the treatment. Invasive probes induce several artifacts in ultrasound fields. The magnitude of these artifacts is probe dependent. Several different probes were evaluated for hyperthermia purposes in this study. An alternative noninvasive method to evaluate the temperature elevations and tissue damage is to use magnetic resonance imaging. The fast imaging sequences used in this study are marginally useful for monitoring hyperthermia. However, these imaging sequences can be utilized to guide and monitor ultrasound surgery.

Animals↗