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Rzechorzek NM, Thrippleton MJ, Chappell FM, Mair G, Ercole A, Cabeleira M, Rhodes J, Marshall I, O'Neill JS. A daily temperature rhythm in the human brain predicts survival after brain injury. Brain 2022; 145:2031-2048. [PMID: 35691613 PMCID: PMC9336587 DOI: 10.1093/brain/awab466] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 11/03/2021] [Accepted: 11/20/2021] [Indexed: 02/06/2023] Open
Abstract
Patients undergo interventions to achieve a 'normal' brain temperature; a parameter that remains undefined for humans. The profound sensitivity of neuronal function to temperature implies the brain should be isothermal, but observations from patients and non-human primates suggest significant spatiotemporal variation. We aimed to determine the clinical relevance of brain temperature in patients by establishing how much it varies in healthy adults. We retrospectively screened data for all patients recruited to the Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) High Resolution Intensive Care Unit Sub-Study. Only patients with direct brain temperature measurements and without targeted temperature management were included. To interpret patient analyses, we prospectively recruited 40 healthy adults (20 males, 20 females, 20-40 years) for brain thermometry using magnetic resonance spectroscopy. Participants were scanned in the morning, afternoon, and late evening of a single day. In patients (n = 114), brain temperature ranged from 32.6 to 42.3°C and mean brain temperature (38.5 ± 0.8°C) exceeded body temperature (37.5 ± 0.5°C, P < 0.0001). Of 100 patients eligible for brain temperature rhythm analysis, 25 displayed a daily rhythm, and the brain temperature range decreased in older patients (P = 0.018). In healthy participants, brain temperature ranged from 36.1 to 40.9°C; mean brain temperature (38.5 ± 0.4°C) exceeded oral temperature (36.0 ± 0.5°C) and was 0.36°C higher in luteal females relative to follicular females and males (P = 0.0006 and P < 0.0001, respectively). Temperature increased with age, most notably in deep brain regions (0.6°C over 20 years, P = 0.0002), and varied spatially by 2.41 ± 0.46°C with highest temperatures in the thalamus. Brain temperature varied by time of day, especially in deep regions (0.86°C, P = 0.0001), and was lowest at night. From the healthy data we built HEATWAVE-a 4D map of human brain temperature. Testing the clinical relevance of HEATWAVE in patients, we found that lack of a daily brain temperature rhythm increased the odds of death in intensive care 21-fold (P = 0.016), whilst absolute temperature maxima or minima did not predict outcome. A warmer mean brain temperature was associated with survival (P = 0.035), however, and ageing by 10 years increased the odds of death 11-fold (P = 0.0002). Human brain temperature is higher and varies more than previously assumed-by age, sex, menstrual cycle, brain region, and time of day. This has major implications for temperature monitoring and management, with daily brain temperature rhythmicity emerging as one of the strongest single predictors of survival after brain injury. We conclude that daily rhythmic brain temperature variation-not absolute brain temperature-is one way in which human brain physiology may be distinguished from pathophysiology.
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Affiliation(s)
| | - Michael J Thrippleton
- Edinburgh Imaging (Royal Infirmary of Edinburgh) Facility, Edinburgh EH16 4SA, UK.,Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Francesca M Chappell
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Grant Mair
- Edinburgh Imaging (Royal Infirmary of Edinburgh) Facility, Edinburgh EH16 4SA, UK.,Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Ari Ercole
- Division of Anaesthesia, University of Cambridge, Box 93 Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Manuel Cabeleira
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Box 167, Cambridge Biomedical Campus, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | | | - Jonathan Rhodes
- Department of Anaesthesia, Critical Care and Pain Medicine, NHS Lothian, Room No. S8208 (2nd Floor), Royal Infirmary of Edinburgh, Edinburgh EH16 4SA, UK
| | - Ian Marshall
- Edinburgh Imaging (Royal Infirmary of Edinburgh) Facility, Edinburgh EH16 4SA, UK.,Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - John S O'Neill
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
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Wang Z, Mascarenhas C, Jia X. Positron Emission Tomography After Ischemic Brain Injury: Current Challenges and Future Developments. Transl Stroke Res 2020; 11:628-642. [PMID: 31939060 PMCID: PMC7347441 DOI: 10.1007/s12975-019-00765-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 11/22/2019] [Accepted: 12/04/2019] [Indexed: 12/19/2022]
Abstract
Positron emission tomography (PET) is widely used in clinical and animal studies, along with the development of diverse tracers. The biochemical characteristics of PET tracers may help uncover the pathophysiological consequences of cardiac arrest (CA) and ischemic stroke, which include cerebral ischemia and reperfusion, depletion of oxygen and glucose, and neuroinflammation. PubMed was searched for studies of the application of PET for "cardiac arrest," "ischemic stroke," and "targeted temperature management." Available studies were included and classified according to the biochemical properties involved and metabolic processes of PET tracers, and were summarized. The mechanisms of ischemic brain injuries were investigated by PET with various tracers to elucidate the pathological process from the initial decrease of cerebral blood flow (CBF) to the subsequent abnormalities in energy and oxygen metabolism, to the monitoring of inflammation. In general, the trends of cerebral blood flow and oxygen metabolism after ischemic attack are not unidirectional but closely related to the time point of injury and recovery. Glucose metabolism after injury showed significant differences in different brain regions whereas global cerebral metabolic rate of glucose (CMRglc) declined. PET monitoring of neuroinflammation shows comparable efficacy to immunostaining. The technology of PET targeting in brain metabolism and the development of tracers provide new tools to track and evaluate the brain's pathological changes after ischemic brain injury. Despite no existing evidence for an available PET-based prediction method, discoveries of new tracers are expected to provide more possibilities for the whole field.
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Affiliation(s)
- Zhuoran Wang
- Department of Critical Care Medicine, Zhongnan Hospital of Wuhan University, Wuhan, 43007, China
- Department of Neurosurgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF Building 823, Baltimore, MD, 21201, USA
| | - Conrad Mascarenhas
- Department of Neurosurgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF Building 823, Baltimore, MD, 21201, USA
| | - Xiaofeng Jia
- Department of Neurosurgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF Building 823, Baltimore, MD, 21201, USA.
- Department of Orthopedics, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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Dehkharghani S, Qiu D. MR Thermometry in Cerebrovascular Disease: Physiologic Basis, Hemodynamic Dependence, and a New Frontier in Stroke Imaging. AJNR Am J Neuroradiol 2020; 41:555-565. [PMID: 32139425 DOI: 10.3174/ajnr.a6455] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 01/02/2020] [Indexed: 01/20/2023]
Abstract
The remarkable temperature sensitivity of the brain is widely recognized and has been studied for its role in the potentiation of ischemic and other neurologic injuries. Pyrexia frequently complicates large-vessel acute ischemic stroke and develops commonly in critically ill neurologic patients; the profound sensitivity of the brain even to minor intraischemic temperature changes, together with the discovery of brain-to-systemic as well as intracerebral temperature gradients, has thus compelled the exploration of cerebral thermoregulation and uncovered its immutable dependence on cerebral blood flow. A lack of pragmatic and noninvasive tools for spatially and temporally resolved brain thermometry has historically restricted empiric study of cerebral temperature homeostasis; however, MR thermometry (MRT) leveraging temperature-sensitive nuclear magnetic resonance phenomena is well-suited to bridging this long-standing gap. This review aims to introduce the reader to the following: 1) fundamental aspects of cerebral thermoregulation, 2) the physical basis of noninvasive MRT, and 3) the physiologic interdependence of cerebral temperature, perfusion, metabolism, and viability.
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Affiliation(s)
- S Dehkharghani
- From the Department of Radiology (S.D.), New York University Langone Health, New York, New York
| | - D Qiu
- Department of Radiology (D.Q.), Emory University Hospital, Atlanta, Georgia
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Tsutsui S, Nanba T, Yoshioka Y, Sasaki M, Fujiwara S, Kobayashi M, Yoshida K, Miyoshi K, Sato S, Ogasawara K. Preoperative brain temperature imaging on proton magnetic resonance spectroscopy predicts hemispheric ischemia during carotid endarterectomy for unilateral carotid stenosis with inadequate collateral blood flow. Neurol Res 2018; 40:617-623. [PMID: 29600890 DOI: 10.1080/01616412.2018.1457130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Objective Preoperative magnetic resonance (MR) angiography sometimes shows the absence of collateral flow via the circle of Willis. This study examined whether brain temperature (BT) imaging on multi-voxel proton MR spectroscopy after this finding increases the accuracy of predicting hemispheric ischemia during internal carotid artery (ICA) clamping during endarterectomy for patients with symptomatic unilateral carotid stenosis. Methods In 52 patients with ICA stenosis (≥70%) and absence of collateral blood flow via the circle of Willis on preoperative MR angiography, BT imaging was displayed using proton multi-voxel MR spectroscopy. The difference between BTs in the affected and contralateral hemispheres (BTaffected hemisphere - BTcontralateral hemisphere) in the deep white matter of the centrum semiovale was calculated and defined as hemispheric ΔBT. Development of cerebral hemispheric ischemia during ICA clamping was determined from intraoperative electroencephalography (EEG). Results Multivariate analysis revealed that high preoperative hemispheric ΔBT was significantly associated with development of EEG-defined hemispheric ischemia (95% confidence intervals [CIs], 5.376-15.452; p = 0.006). The positive-predictive value for development of EEG-defined hemispheric ischemia was significantly greater for preoperative hemispheric ΔBT following preoperative MR angiography (95%CI, 42-87%) than for preoperative MR angiography alone (95%CI, 13-37%). Conclusions For patients without collateral flow via the circle of Willis, BT imaging increases the predictive accuracy for development of hemispheric ischemia during ICA clamping during CEA.
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Affiliation(s)
- Shouta Tsutsui
- a Department of Neurosurgery , Iwate Medical University , Morioka , Japan
| | - Takamasa Nanba
- a Department of Neurosurgery , Iwate Medical University , Morioka , Japan
| | - Yoshichika Yoshioka
- b Open and Transdisciplinary Research Initiatives , Osaka University , Suita , Japan
| | - Makoto Sasaki
- c Division of Ultra-High Field MRI, School of Medicine , Iwate Medical University , Morioka , Japan
| | - Shunrou Fujiwara
- a Department of Neurosurgery , Iwate Medical University , Morioka , Japan
| | - Masakazu Kobayashi
- a Department of Neurosurgery , Iwate Medical University , Morioka , Japan
| | - Kenji Yoshida
- a Department of Neurosurgery , Iwate Medical University , Morioka , Japan
| | - Kenya Miyoshi
- a Department of Neurosurgery , Iwate Medical University , Morioka , Japan
| | - Shinpei Sato
- a Department of Neurosurgery , Iwate Medical University , Morioka , Japan
| | - Kuniaki Ogasawara
- a Department of Neurosurgery , Iwate Medical University , Morioka , Japan
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