Abstract P324: Your Brain May Be "HOTTER" Than You Think, Results From Phase I Check Brain Temperature Study

Background: Hypothermia is a known neuronal protecting agent and used in post cardiac arrest. However, its use for stroke and brain trauma has not made any progress due to the lack of accurate way of measuring brain temperature. Hence, hypothermic degree and duration for it to be therapeutic is unknown. The phase I Check Brain Temperature Study was to define regional brain temperatures in normal individuals via MRI thermometry. The established brain temperature map can be used as the baseline to provide therapeutic hypothermia. Method: Temperatures of 5 regions of interest (ROI) of brain (frontal lobe, thalamus, hypothalamus, occipital lobe and cerebellum) were measured in 10 healthy individuals by using proton resonance frequency MRI spectroscopy single voxel method. The scanning protocol include a whole brain anatomical images, (3DFSPGR : TR/TE=150/3.9ms, FOV=24cm,matrix=256x256, slice thickness =1 mm.) and spectroscopy PRESS (TR/TE=1500/144 ms, 8 nex, 2 x 2 x 2 cm^3) on a GE 3T scanner. Ten right handed men (18<age<80) were recruited and their oral and tympanic temperatures were monitored. Average whole head temperature=average of oral temp+tympanic temp and average brain temp=average of temp of 5 regions of interest. Two tails, paired t-test used to compare temps between subjects and ROIs. Results: Average temperature differences between brain (38.2 °C) and head (36.5 °C) is 1.8 °C (p< 0.0000002). Thalamus has the highest temperature among all ROIs in brain. Brain temperature > oral temperature > tympanic temperature. Conclusion: Brain temperatures may not correlate to body temperatures and there is a regional difference. Our finding will be used as the baseline brain temperature map when hypothermia is applied in patients with hemisphere stroke in the phase II study.

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Gray matter blood flow change is unevenly distributed during moderate isocapnic hypoxia in humans

Journal of Applied Physiology ◽

10.1152/japplphysiol.00069.2007 ◽

2008 ◽

Vol 104 (1) ◽

pp. 212-217 ◽

Cited By ~ 71

Author(s):

Andrew P. Binks ◽

Vincent J. Cunningham ◽

Lewis Adams ◽

Robert B. Banzett

Keyword(s):

Blood Flow ◽

Nucleus Accumbens ◽

Positron Emission Tomography Imaging ◽

Occipital Lobe ◽

Brain Regions ◽

Functional Brain Imaging ◽

Regions Of Interest ◽

Breath Hold ◽

Obstructive Sleep ◽

The Brain

Hypoxia increases cerebral blood flow (CBF), but it is unknown whether this increase is uniform across all brain regions. We used H215O positron emission tomography imaging to measure absolute blood flow in 50 regions of interest across the human brain ( n = 5) during normoxia and moderate hypoxia. Pco2 was kept constant (∼44 Torr) throughout the study to avoid decreases in CBF associated with the hypocapnia that normally occurs with hypoxia. Breathing was controlled by mechanical ventilation. During hypoxia (inspired Po2 = 70 Torr), mean end-tidal Po2 fell to 45 ± 6.3 Torr (means ± SD). Mean global CBF increased from normoxic levels of 0.39 ± 0.13 to 0.45 ± 0.13 ml/g during hypoxia. Increases in regional CBF were not uniform and ranged from 9.9 ± 8.6% in the occipital lobe to 28.9 ± 10.3% in the nucleus accumbens. Regions of interest that were better perfused during normoxia generally showed a greater regional CBF response. Phylogenetically older regions of the brain tended to show larger vascular responses to hypoxia than evolutionary younger regions, e.g., the putamen, brain stem, thalamus, caudate nucleus, nucleus accumbens, and pallidum received greater than average increases in blood flow, while cortical regions generally received below average increases. The heterogeneous blood flow distribution during hypoxia may serve to protect regions of the brain with essential homeostatic roles. This may be relevant to conditions such as altitude, breath-hold diving, and obstructive sleep apnea, and may have implications for functional brain imaging studies that involve hypoxia.

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Effects of Pharyngeal Cooling on Brain Temperature in Primates and Humans

Anesthesiology ◽

10.1097/aln.0b013e3182580536 ◽

2012 ◽

Vol 117 (1) ◽

pp. 117-125 ◽

Cited By ~ 12

Author(s):

Yoshimasa Takeda ◽

Hiroshi Hashimoto ◽

Koji Fumoto ◽

Tetsuya Danura ◽

Hiromichi Naito ◽

...

Keyword(s):

Blood Pressure ◽

Cardiac Arrest ◽

Brain Temperature ◽

Spontaneous Circulation ◽

Tympanic Temperature ◽

Control Group ◽

Bladder Temperature ◽

Pharyngeal Epithelium ◽

C 30 ◽

Affect Heart Rate

Background Pharyngeal cooling decreases brain temperature by cooling carotid arteries. This study was designed to evaluate the principle of pharyngeal cooling in monkeys and humans. Methods Monkeys (n = 10) were resuscitated following 12 min of cardiac arrest. Pharyngeal cooling (n = 5), in which cold saline (5°C) was perfused into the cuff at the rate of 500 ml/min, was initiated simultaneously with the onset of resuscitation for 30 min. Patients (n = 3) who were in an intensive care unit were subjected to 30 min of pharyngeal cooling under propofol anesthesia. Results In the animal study, core brain temperature was significantly decreased compared with that in the control group by 1.9°C (SD = 0.8, P < 0.001) and 3.1°C (SD = 1.0, P < 0.001) at 10 min and 30 min after the onset of cooling, respectively. The cooling effect was more evident in an animal with low postresuscitation blood pressure. Total dose of epinephrine, number of direct current shocks, and recovery of blood pressure were not different between the two groups. The pharyngeal epithelium was microscopically intact on day 5. In the clinical study, insertion of the cuff and start of perfusion did not affect heart rate or blood pressure. Tympanic temperature was decreased by 0.6 ± 0.1°C/30 min without affecting bladder temperature. The pharynx was macroscopically intact for 3 days. Conclusions Pharyngeal cooling rapidly and selectively decreased brain temperature in primates and tympanic temperature in humans and did not have adverse effects on return of spontaneous circulation, even when initiated during cardiac arrest in primates.

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Relationships Between Brain and Body Temperature, Clinical and Imaging Outcomes after Ischemic Stroke

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.2013.52 ◽

2013 ◽

Vol 33 (7) ◽

pp. 1083-1089 ◽

Cited By ~ 28

Author(s):

Bartosz Karaszewski ◽

Trevor K Carpenter ◽

Ralph GR Thomas ◽

Paul A Armitage ◽

Georgina Katherine S Lymer ◽

...

Keyword(s):

Body Temperature ◽

Functional Outcome ◽

Brain Temperature ◽

Tissue Response ◽

Tympanic Temperature ◽

Resonance Spectroscopy ◽

Stroke Severity ◽

Poor Functional Outcome ◽

Ischemic Lesion ◽

Ischemic Brain

Pyrexia soon after stroke is associated with severe stroke and poor functional outcome. Few studies have assessed brain temperature after stroke in patients, so little is known of its associations with body temperature, stroke severity, or outcome. We measured temperatures in ischemic and normal-appearing brain using 1 H-magnetic resonance spectroscopy and its correlations with body (tympanic) temperature measured four-hourly, infarct growth by 5 days, early neurologic (National Institute of Health Stroke Scale, NIHSS) and late functional outcome (death or dependency). Among 40 patients (mean age 73 years, median NIHSS 7, imaged at median 17 hours), temperature in ischemic brain was higher than in normal-appearing brain on admission (38.6°C-core, 37.9°C-contralateral hemisphere, P = 0.03) but both were equally elevated by 5 days;both were higher than tympanic temperature. Ischemic lesion temperature was not associated with NIHSS or 3-month functional outcome;in contrast, higher contralateral normal-appearing brain temperature was associated with worse NIHSS, infarct expansion and poor functional outcome, similar to associations for tympanic temperature. We conclude that brain temperature is higher than body temperature;that elevated temperature in ischemic brain reflects a local tissue response to ischemia, whereas pyrexia reflects the systemic response to stroke, occurs later, and is associated with adverse outcomes.

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148 Harnessing multi-media approaches to support the learning of the lymphatics system in radiation medicine. Phase I: Developing the electronic anatomical images and The accompanying text

Radiotherapy and Oncology ◽

10.1016/s0167-8140(04)80648-0 ◽

2004 ◽

Vol 72 ◽

pp. S45

Keyword(s):

Phase I ◽

Anatomical Images ◽

Multi Media ◽

Radiation Medicine

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Deep-learning-based attenuation correction in dynamic [15O]H2O studies using PET/MRI in healthy volunteers

Journal of Cerebral Blood Flow & Metabolism ◽

10.1177/0271678x211029178 ◽

2021 ◽

pp. 0271678X2110291

Author(s):

Oriol Puig ◽

Otto M Henriksen ◽

Flemming L Andersen ◽

Ulrich Lindberg ◽

Liselotte Højgaard ◽

...

Keyword(s):

Attenuation Correction ◽

Activity Concentration ◽

Reference Method ◽

Occipital Lobe ◽

Brain Regions ◽

Regions Of Interest ◽

Whole Brain ◽

Ultrashort Echo Time ◽

Positron Emission ◽

Static Images

Quantitative [15O]H2O positron emission tomography (PET) is the accepted reference method for regional cerebral blood flow (rCBF) quantification. To perform reliable quantitative [15O]H2O-PET studies in PET/MRI scanners, MRI-based attenuation-correction (MRAC) is required. Our aim was to compare two MRAC methods (RESOLUTE and DeepUTE) based on ultrashort echo-time with computed tomography-based reference standard AC (CTAC) in dynamic and static [15O]H2O-PET. We compared rCBF from quantitative perfusion maps and activity concentration distribution from static images between AC methods in 25 resting [15O]H2O-PET scans from 14 healthy men at whole-brain, regions of interest and voxel-wise levels. Average whole-brain CBF was 39.9 ± 6.0, 39.0 ± 5.8 and 40.0 ± 5.6 ml/100 g/min for CTAC, RESOLUTE and DeepUTE corrected studies respectively. RESOLUTE underestimated whole-brain CBF by 2.1 ± 1.50% and rCBF in all regions of interest (range −2.4%– −1%) compared to CTAC. DeepUTE showed significant rCBF overestimation only in the occipital lobe (0.6 ± 1.1%). Both MRAC methods showed excellent correlation on rCBF and activity concentration with CTAC, with slopes of linear regression lines between 0.97 and 1.01 and R2 over 0.99. In conclusion, RESOLUTE and DeepUTE provide AC information comparable to CTAC in dynamic [15O]H2O-PET but RESOLUTE is associated with a small but systematic underestimation.

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Cerebral Hyperthermia in Children after Cardiopulmonary Bypass

Anesthesiology ◽

10.1097/00000542-200009000-00008 ◽

2000 ◽

Vol 93 (3) ◽

pp. 611-618 ◽

Cited By ~ 46

Author(s):

Bruno Bissonnette ◽

Helen M. Holtby ◽

Annette J. Davis ◽

Hweeleng Pua ◽

Fay J. Gilder ◽

...

Keyword(s):

Cardiopulmonary Bypass ◽

Brain Temperature ◽

Correlation Coefficients ◽

Jugular Bulb ◽

Infants And Children ◽

Tympanic Temperature ◽

Neurologic Injury ◽

The Mean ◽

Kinetics Of ◽

Jugular Bulb Catheter

Background Cerebral hyperthermia after hypothermic cardiopulmonary bypass has been poorly documented for adults and never in children. This study was designed to monitor brain temperature during and up to 6 h after cardiopulmonary bypass in infants and children. Methods Fifteen infants and children, between 3 months and 6 yr of age, were studied. A right retrograde jugular bulb catheter was used to measure the jugular venous bulb temperature (JVBT) during the procedure and the first 6 h in the critical care unit. The temperature of the blood from the bypass machine was measured at the aorta through the cannula using an indwelling temperature probe. All data were acquired every minute. Results The age of the patients ranged from 3 to 71 months (median, 15 months). The mean weight was 11.5 +/- 8.4 kg. The mean JVBT recorded at the end of cardiopulmonary bypass was 36.9 +/- 1.4 degrees C but reached 39.6 +/- 0.8 degrees C after six h (P < 0.01). The kinetics of brain rewarming was determined by the slope of the mean JVBT and corresponded to y +/- 0.006x + 37.21 (r2 = 0.97). The JVBT differed from the tympanic temperature after 200 min (P < 0.01) and the lower esophageal (P < 0.05) and rectal (P < 0.001) temperatures after 300 min. After 6 h, the tympanic, rectal, and lower esophageal temperatures were 37.8 +/- 0.9, 37.7 +/- 0.6, and 38.4 +/- 0.7 degrees C, respectively, whereas the JVBT was 39.6 +/- 0.8 degrees C (P < 0.001). However, the correlation coefficients between the JVBT and the tympanic, rectal, and esophageal temperatures were 0.98, 0. 85, and 0.97, respectively. No complications were recorded with placement of the jugular bulb catheter. Conclusions Mean JVBT was significantly increased over the mean core temperature at all times from rewarming by cardiopulmonary bypass onward. Although the lower esophageal, rectal, and tympanic temperatures correlated well with JVBT, all three failed to reflect JVBT during recovery. This observation might help to elucidate factors involved in the functional and structural neurologic injury known to occur in pediatric patients.

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CT Volumetry of Convoluted Objects—A Simple Method Using Volume Averaging

Tomography ◽

10.3390/tomography7020011 ◽

2021 ◽

Vol 7 (2) ◽

pp. 120-129

Author(s):

Rani Al-Senan ◽

Jeffrey H. Newhouse

Keyword(s):

Computed Tomography ◽

Spatial Resolution ◽

Computer Programs ◽

Volume Averaging ◽

Image Noise ◽

Regions Of Interest ◽

Slice Thickness ◽

Petroleum Jelly ◽

Ct Volumetry ◽

Simple Method

Accurate measurement of object volumes using computed tomography is often important but can be challenging, especially for finely convoluted objects with severe marginal blurring from volume averaging. We aimed to test the accuracy of a simple method for volumetry by constructing, scanning and analyzing a phantom object with these characteristics which consisted of a cluster of small lucite beads embedded in petroleum jelly. Our method involves drawing simple regions of interest containing the entirety of the object and a portion of the surrounding material and using its density, along with the densities of pure lucite and petroleum jelly and the slice thickness to calculate the volume of the object in each slice. Comparison of our results with the object’s true volume showed the technique to be highly accurate, irrespective of slice thickness, image noise, reconstruction planes, spatial resolution and variations in regions of interest. We conclude that the method can be easily used for accurate volumetry in clinical and research scans without the need for specialized volumetry computer programs.

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Insight into the use of tympanic temperature during target temperature management in emergency and critical care: a scoping review

Journal of Intensive Care ◽

10.1186/s40560-021-00558-4 ◽

2021 ◽

Vol 9 (1) ◽

Author(s):

Michela Masè ◽

Alessandro Micarelli ◽

Marika Falla ◽

Ivo B. Regli ◽

Giacomo Strapazzon

Keyword(s):

Core Temperature ◽

Scoping Review ◽

Brain Temperature ◽

Temperature Measurements ◽

Tympanic Temperature ◽

Temperature Management ◽

Target Temperature Management ◽

Target Temperature ◽

Temperature Changes ◽

Clinical Conditions

Abstract Background Target temperature management (TTM) is suggested to reduce brain damage in the presence of global or local ischemia. Prompt TTM application may help to improve outcomes, but it is often hindered by technical problems, mainly related to the portability of cooling devices and temperature monitoring systems. Tympanic temperature (TTy) measurement may represent a practical, non-invasive approach for core temperature monitoring in emergency settings, but its accuracy under different TTM protocols is poorly characterized. The present scoping review aimed to collect the available evidence about TTy monitoring in TTM to describe the technique diffusion in various TTM contexts and its accuracy in comparison with other body sites under different cooling protocols and clinical conditions. Methods The scoping review was conducted following the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analysis extension for scoping reviews (PRISMA-ScR). PubMed, Scopus, and Web of Science electronic databases were systematically searched to identify studies conducted in the last 20 years, where TTy was measured in TTM context with specific focus on pre-hospital or in-hospital emergency settings. Results The systematic search identified 35 studies, 12 performing TTy measurements during TTM in healthy subjects, 17 in patients with acute cardiovascular events, and 6 in patients with acute neurological diseases. The studies showed that TTy was able to track temperature changes induced by either local or whole-body cooling approaches in both pre-hospital and in-hospital settings. Direct comparisons to other core temperature measurements from other body sites were available in 22 studies, which showed a faster and larger change of TTy upon TTM compared to other core temperature measurements. Direct brain temperature measurements were available only in 3 studies and showed a good correlation between TTy and brain temperature, although TTy displayed a tendency to overestimate cooling effects compared to brain temperature. Conclusions TTy was capable to track temperature changes under a variety of TTM protocols and clinical conditions in both pre-hospital and in-hospital settings. Due to the heterogeneity and paucity of comparative temperature data, future studies are needed to fully elucidate the advantages of TTy in emergency settings and its capability to track brain temperature.

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