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Huang J, Chen Z, van Zijl PCM, Law LH, Pemmasani Prabakaran RS, Park SW, Xu J, Chan KWY. Effect of inhaled oxygen level on dynamic glucose-enhanced MRI in mouse brain. Magn Reson Med 2024; 92:57-68. [PMID: 38308151 PMCID: PMC11055662 DOI: 10.1002/mrm.30035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 12/23/2023] [Accepted: 01/15/2024] [Indexed: 02/04/2024]
Abstract
PURPOSE To investigate the effect of inhaled oxygen level on dynamic glucose enhanced (DGE) MRI in mouse brain tissue and CSF at 3 T. METHODS DGE data of brain tissue and CSF from mice under normoxia or hyperoxia were acquired in independent and interleaved experiments using on-resonance variable delay multi-pulse (onVDMP) MRI. A bolus of 0.15 mL filtered 50% D-glucose was injected through the tail vein over 1 min during DGE acquisition. MRS was acquired before and after DGE experiments to confirm the presence of D-glucose. RESULTS A significantly higher DGE effect under normoxia than under hyperoxia was observed in brain tissue (p = 0.0001 and p = 0.0002 for independent and interleaved experiments, respectively), but not in CSF (p > 0.3). This difference is attributed to the increased baseline MR tissue signal under hyperoxia induced by a shortened T1 and an increased BOLD effect. When switching from hyperoxia to normoxia without glucose injection, a signal change of ˜3.0% was found in brain tissue and a signal change of ˜1.5% was found in CSF. CONCLUSIONS DGE signal was significantly lower under hyperoxia than that under normoxia in brain tissue, but not in CSF. The reason is that DGE effect size of brain tissue is affected by the baseline signal, which could be influenced by T1 change and BOLD effect. Therefore, DGE experiments in which the oxygenation level is changed from baseline need to be interpreted carefully.
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Affiliation(s)
- Jianpan Huang
- Department of Diagnostic Radiology, The University of Hong Kong, Hong Kong, China
| | - Zilin Chen
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Peter CM van Zijl
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, USA
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Lok Hin Law
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Rohith Saai Pemmasani Prabakaran
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
- Hong Kong Centre for Cerebro-Cardiovascular Health Engineering (COCHE), Hong Kong, China
| | - Se Weon Park
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
- Hong Kong Centre for Cerebro-Cardiovascular Health Engineering (COCHE), Hong Kong, China
| | - Jiadi Xu
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, USA
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Kannie WY Chan
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Hong Kong Centre for Cerebro-Cardiovascular Health Engineering (COCHE), Hong Kong, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, China
- Tung Biomedical Science Centre, City University of Hong Kong, Hong Kong, China
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Lee H, Xu J, Fernandez-Seara MA, Wehrli FW. Validation of a new 3D quantitative BOLD based cerebral oxygen extraction mapping. J Cereb Blood Flow Metab 2024; 44:1184-1198. [PMID: 38289876 PMCID: PMC11179617 DOI: 10.1177/0271678x231220332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 10/06/2023] [Accepted: 10/09/2023] [Indexed: 02/01/2024]
Abstract
Quantitative BOLD (qBOLD) MRI allows evaluation of oxidative metabolism of the brain based purely on an endogenous contrast mechanism. The method quantifies deoxygenated blood volume (DBV) and hemoglobin oxygen saturation level of venous blood (Yv), yielding oxygen extraction fraction (OEF), and along with a separate measurement of cerebral blood flow, cerebral metabolic rate of oxygen (CMRO2) maps. Here, we evaluated our recently reported 3D qBOLD method that rectifies a number of deficiencies in prior qBOLD approaches in terms of repeat reproducibility and sensitivity to hypercapnia on the metabolic parameters, and in comparison to dual-gas calibrated BOLD (cBOLD) MRI for determining resting-state oxygen metabolism. Results suggested no significant difference between test-retest qBOLD scans in either DBV and OEF. Exposure to hypercapnia yielded group averages of 38 and 28% for OEF and 151 and 146 µmol/min/100 g for CMRO2 in gray matter at baseline and hypercapnia, respectively. The decrease of OEF during hypercapnia was significant (p ≪ 0.01), whereas CMRO2 did not change significantly (p = 0.25). Finally, baseline OEF (37 vs. 39%) and CMRO2 (153 vs. 145 µmol/min/100 g) in gray matter using qBOLD and dual-gas cBOLD were found to be in good agreement with literature values, and were not significantly different from each other (p > 0.1).
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Affiliation(s)
- Hyunyeol Lee
- School of Electronic and Electrical Engineering, Kyungpook National University, Daegu, Republic of Korea
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jing Xu
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Maria A Fernandez-Seara
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Radiology, Clinica Universidad de Navarra, Pamplona, Spain
| | - Felix W Wehrli
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Vasilkovska T, Salajeghe S, Vanreusel V, Van Audekerke J, Verschuuren M, Hirschler L, Warnking J, Pintelon I, Pustina D, Cachope R, Mrzljak L, Muñoz-Sanjuan I, Barbier EL, De Vos WH, Van der Linden A, Verhoye M. Longitudinal alterations in brain perfusion and vascular reactivity in the zQ175DN mouse model of Huntington's disease. J Biomed Sci 2024; 31:37. [PMID: 38627751 PMCID: PMC11022401 DOI: 10.1186/s12929-024-01028-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 04/08/2024] [Indexed: 04/19/2024] Open
Abstract
BACKGROUND Huntington's disease (HD) is marked by a CAG-repeat expansion in the huntingtin gene that causes neuronal dysfunction and loss, affecting mainly the striatum and the cortex. Alterations in the neurovascular coupling system have been shown to lead to dysregulated energy supply to brain regions in several neurological diseases, including HD, which could potentially trigger the process of neurodegeneration. In particular, it has been observed in cross-sectional human HD studies that vascular alterations are associated to impaired cerebral blood flow (CBF). To assess whether whole-brain changes in CBF are present and follow a pattern of progression, we investigated both resting-state brain perfusion and vascular reactivity longitudinally in the zQ175DN mouse model of HD. METHODS Using pseudo-continuous arterial spin labelling (pCASL) MRI in the zQ175DN model of HD and age-matched wild-type (WT) mice, we assessed whole-brain, resting-state perfusion at 3, 6 and 9 and 13 months of age, and assessed hypercapnia-induced cerebrovascular reactivity (CVR), at 4.5, 6, 9 and 15 months of age. RESULTS We found increased perfusion in cortical regions of zQ175DN HET mice at 3 months of age, and a reduction of this anomaly at 6 and 9 months, ages at which behavioural deficits have been reported. On the other hand, under hypercapnia, CBF was reduced in zQ175DN HET mice as compared to the WT: for multiple brain regions at 6 months of age, for only somatosensory and retrosplenial cortices at 9 months of age, and brain-wide by 15 months. CVR impairments in cortical regions, the thalamus and globus pallidus were observed in zQ175DN HET mice at 9 months, with whole brain reactivity diminished at 15 months of age. Interestingly, blood vessel density was increased in the motor cortex at 3 months, while average vessel length was reduced in the lateral portion of the caudate putamen at 6 months of age. CONCLUSION Our findings reveal early cortical resting-state hyperperfusion and impaired CVR at ages that present motor anomalies in this HD model, suggesting that further characterization of brain perfusion alterations in animal models is warranted as a potential therapeutic target in HD.
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Affiliation(s)
- Tamara Vasilkovska
- Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium.
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium.
| | - Somaie Salajeghe
- Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
| | - Verdi Vanreusel
- Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
| | - Johan Van Audekerke
- Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
| | - Marlies Verschuuren
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
- Laboratory of Cell Biology and Histology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
- Antwerp Centre for Advanced Microscopy, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
| | - Lydiane Hirschler
- C.J. Gorter MRI Center, Leiden University Medical Center, Leiden, the Netherlands
| | - Jan Warnking
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, Grenoble, France
| | - Isabel Pintelon
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
- Laboratory of Cell Biology and Histology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
- Antwerp Centre for Advanced Microscopy, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
| | - Dorian Pustina
- CHDI Management, Inc., the company that manages the scientific activities of CHDI Foundation, Inc, Princeton, NJ, USA
| | - Roger Cachope
- CHDI Management, Inc., the company that manages the scientific activities of CHDI Foundation, Inc, Princeton, NJ, USA
| | - Ladislav Mrzljak
- CHDI Management, Inc., the company that manages the scientific activities of CHDI Foundation, Inc, Princeton, NJ, USA
- Present Address: Takeda Pharmaceuticals, Cambridge, MA, USA
| | - Ignacio Muñoz-Sanjuan
- CHDI Management, Inc., the company that manages the scientific activities of CHDI Foundation, Inc, Princeton, NJ, USA
- Present Address: Cajal Neuroscience Inc, Seattle, WA, USA
| | - Emmanuel L Barbier
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, Grenoble, France
| | - Winnok H De Vos
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
- Laboratory of Cell Biology and Histology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
- Antwerp Centre for Advanced Microscopy, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
| | - Annemie Van der Linden
- Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
| | - Marleen Verhoye
- Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
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Gil R, Valente M, Shemesh N. Rat superior colliculus encodes the transition between static and dynamic vision modes. Nat Commun 2024; 15:849. [PMID: 38346973 PMCID: PMC10861507 DOI: 10.1038/s41467-024-44934-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 01/09/2024] [Indexed: 02/15/2024] Open
Abstract
The visual continuity illusion involves a shift in visual perception from static to dynamic vision modes when the stimuli arrive at high temporal frequency, and is critical for recognizing objects moving in the environment. However, how this illusion is encoded across the visual pathway remains poorly understood, with disparate frequency thresholds at retinal, cortical, and behavioural levels suggesting the involvement of other brain areas. Here, we employ a multimodal approach encompassing behaviour, whole-brain functional MRI, and electrophysiological measurements, for investigating the encoding of the continuity illusion in rats. Behavioural experiments report a frequency threshold of 18±2 Hz. Functional MRI reveal that superior colliculus signals transition from positive to negative at the behaviourally-driven threshold, unlike thalamic and cortical areas. Electrophysiological recordings indicate that these transitions are underpinned by neural activation/suppression. Lesions in the primary visual cortex reveal this effect to be intrinsic to the superior colliculus (under a cortical gain effect). Our findings highlight the superior colliculus' crucial involvement in encoding temporal frequency shifts, especially the change from static to dynamic vision modes.
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Affiliation(s)
- Rita Gil
- Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal
| | - Mafalda Valente
- Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal
| | - Noam Shemesh
- Champalimaud Research, Champalimaud Foundation, Lisbon, Portugal.
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5
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Buxton RB. Thermodynamic limitations on brain oxygen metabolism: physiological implications. J Physiol 2024; 602:683-712. [PMID: 38349000 DOI: 10.1113/jp284358] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 01/03/2024] [Indexed: 02/20/2024] Open
Abstract
Recent thermodynamic modelling indicates that maintaining the brain tissue ratio of O2 to CO2 (abbreviated tissue O2 /CO2 ) is critical for preserving the entropy increase available from oxidative metabolism of glucose, with a fall of that available entropy leading to a reduction of the phosphorylation potential and impairment of brain energy metabolism. This provides a novel perspective for understanding physiological responses under different conditions in terms of preserving tissue O2 /CO2 . To enable estimation of tissue O2 /CO2 in the human brain, a detailed mathematical model of O2 and CO2 transport was developed, and applied to reported physiological responses to different challenges, asking: how well is tissue O2 /CO2 preserved? Reported experimental results for increased neural activity, hypercapnia and hypoxia due to high altitude are consistent with preserving tissue O2 /CO2 . The results highlight two physiological mechanisms that control tissue O2 /CO2 : cerebral blood flow, which modulates tissue O2 ; and ventilation rate, which modulates tissue CO2 . The hypoxia modelling focused on humans at high altitude, including acclimatized lowlanders and Tibetan and Andean adapted populations, with a primary finding that decreasing CO2 by increasing ventilation rate is more effective for preserving tissue O2 /CO2 than increasing blood haemoglobin content to maintain O2 delivery to tissue. This work focused on the function served by particular physiological responses, and the underlying mechanisms require further investigation. The modelling provides a new framework and perspective for understanding how blood flow and other physiological factors support energy metabolism in the brain under a wide range of conditions. KEY POINTS: Thermodynamic modelling indicates that preserving the O2 /CO2 ratio in brain tissue is critical for preserving the entropy change available from oxidative metabolism of glucose and the phosphorylation potential underlying energy metabolism. A detailed model of O2 and CO2 transport was developed to allow estimation of the tissue O2 /CO2 ratio in the human brain in different physiological states. Reported experimental results during hypoxia, hypercapnia and increased oxygen metabolic rate in response to increased neural activity are consistent with maintaining brain tissue O2 /CO2 ratio. The hypoxia modelling of high-altitude acclimatization and adaptation in humans demonstrates the critical role of reducing CO2 with increased ventilation for preserving tissue O2 /CO2 . Preservation of tissue O2 /CO2 provides a novel perspective for understanding the function of observed physiological responses under different conditions in terms of preserving brain energy metabolism, although the mechanisms underlying these functions are not well understood.
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Affiliation(s)
- Richard B Buxton
- Center for Functional Magnetic Resonance Imaging, Department of Radiology, University of California, San Diego, California, USA
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6
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Dey A, Khandelwal A. Hyperoxia in neurocritical care: Current perspectives. Med J Armed Forces India 2024; 80:10-15. [PMID: 38239601 PMCID: PMC10793228 DOI: 10.1016/j.mjafi.2022.11.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 11/29/2022] [Indexed: 01/18/2023] Open
Abstract
In recent years, a lot of controversies have emerged regarding conservative versus liberal oxygen therapy in critically ill patients. While neurologically injured patients might have higher oxygen demand due to high cerebral metabolism, recent studies have clearly shown that hyperoxia may not be beneficial in improving the neurological outcome in traumatic brain injury, subarachnoid hemorrhage, and acute ischemic stroke. Rather, hyperoxia might worsen neurological outcome in such conditions by various mechanisms like direct cerebral vasoconstriction or by increased excitotoxicity, which in turn leads to lipid peroxidation and generation of harmful reactive oxygen species. This article brings into insight the current evidence on the effect of hyperoxia on these three acute neurological insults.
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Affiliation(s)
- Ankita Dey
- Assistant Professor (Anaesthesia), All India Institute of Medical Sciences (AIIMS), Bathinda, India
| | - Ankur Khandelwal
- Associate Professor (Anaesthesiology, Critical Care & Pain Medicine), All India Institute of Medical Sciences (AIIMS), Guwahati, Assam, India
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7
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Johnson BJ, Lipford ME, Barcus RA, Olson JD, Schaaf GW, Andrews RN, Kim J, Dugan GO, Deycmar S, Reed CA, Whitlow CT, Cline JM. Assessing cerebrovascular reactivity (CVR) in rhesus macaques (Macaca mulatta) using a hypercapnic challenge and pseudo-continuous arterial spin labeling (pCASL). Neuroimage 2024; 285:120491. [PMID: 38070839 PMCID: PMC10842457 DOI: 10.1016/j.neuroimage.2023.120491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 12/01/2023] [Accepted: 12/06/2023] [Indexed: 01/13/2024] Open
Abstract
Cerebrovascular reactivity (CVR) is a measure of cerebral small vessels' ability to respond to changes in metabolic demand and can be quantified using magnetic resonance imaging (MRI) coupled with a vasoactive stimulus. Reduced CVR occurs with neurodegeneration and is associated with cognitive decline. While commonly measured in humans, few studies have evaluated CVR in animal models. Herein, we describe methods to induce hypercapnia in rhesus macaques (Macaca mulatta) under gas anesthesia to measure cerebral blood flow (CBF) and CVR using pseudo-continuous arterial spin labeling (pCASL). Fifteen (13 M, 2 F) adult rhesus macaques underwent pCASL imaging that included a baseline segment (100% O2) followed by a hypercapnic challenge (isoflurane anesthesia with 5% CO2, 95% O2 mixed gas). Relative hypercapnia was defined as an end-tidal CO2 (ETCO2) ≥5 mmHg above baseline ETCO2. The mean ETCO2 during the baseline segment of the pCASL sequence was 34 mmHg (range: 23-48 mmHg). During this segment, mean whole-brain CBF was 51.48 ml/100g/min (range: 21.47-77.23 ml/100g/min). Significant increases (p<0.0001) in ETCO2 were seen upon inspiration of the mixed gas (5% CO2, 95% O2). The mean increase in ETCO2 was 8.5 mmHg and corresponded with a mean increase in CBF of 37.1% (p<0.0001). The mean CVR measured was 4.3%/mmHg. No anesthetic complications occurred as a result of the CO2 challenge. Our methods were effective at inducing a state of relative hypercapnia that corresponds with a detectable increase in whole brain CBF using pCASL MRI. Using these methods, a CO2 challenge can be performed in conjunction with pCASL imaging to evaluate CBF and CVR in rhesus macaques. The measured CVR in rhesus macaques is comparable to human CVR highlighting the translational utility of rhesus macaques in neuroscience research. These methods present a feasible means to measure CVR in comparative models of neurodegeneration and cerebrovascular dysfunction.
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Affiliation(s)
- Brendan J Johnson
- Department of Pathology, Section on Comparative Medicine, Wake Forest University School of Medicine, 1 Medical Center Blvd, Winston-Salem, NC, United States.
| | - Megan E Lipford
- Department of Radiology, Wake Forest University School of Medicine, 1 Medical Center Blvd, Winston-Salem, NC, United States; Department of Biomedical Engineering, Wake Forest University School of Medicine, 1 Medical Center Blvd, Winston-Salem, NC, United States
| | - Richard A Barcus
- Department of Radiology, Wake Forest University School of Medicine, 1 Medical Center Blvd, Winston-Salem, NC, United States
| | - John D Olson
- Department of Pathology, Section on Comparative Medicine, Wake Forest University School of Medicine, 1 Medical Center Blvd, Winston-Salem, NC, United States
| | - George W Schaaf
- Department of Pathology, Section on Comparative Medicine, Wake Forest University School of Medicine, 1 Medical Center Blvd, Winston-Salem, NC, United States
| | - Rachel N Andrews
- Department of Radiation Oncology, Section on Radiation Biology, Wake Forest University School of Medicine, 1 Medical Center Blvd, Winston-Salem, NC, United States
| | - Jeongchul Kim
- Department of Radiology, Wake Forest University School of Medicine, 1 Medical Center Blvd, Winston-Salem, NC, United States
| | - Greg O Dugan
- Department of Pathology, Section on Comparative Medicine, Wake Forest University School of Medicine, 1 Medical Center Blvd, Winston-Salem, NC, United States
| | - Simon Deycmar
- Department of Pathology, Section on Comparative Medicine, Wake Forest University School of Medicine, 1 Medical Center Blvd, Winston-Salem, NC, United States
| | - Colin A Reed
- Department of Pathology, Section on Comparative Medicine, Wake Forest University School of Medicine, 1 Medical Center Blvd, Winston-Salem, NC, United States
| | - Christopher T Whitlow
- Wake Forest Baptist Comprehensive Cancer Center, Wake Forest University School of Medicine, 1 Medical Center Blvd, Winston-Salem, NC, United States; Department of Radiology, Wake Forest University School of Medicine, 1 Medical Center Blvd, Winston-Salem, NC, United States; Department of Biomedical Engineering, Wake Forest University School of Medicine, 1 Medical Center Blvd, Winston-Salem, NC, United States; Department of Biostatistics and Data Science, Wake Forest University School of Medicine, 1 Medical Center Blvd, Winston-Salem, NC, United States
| | - J Mark Cline
- Department of Pathology, Section on Comparative Medicine, Wake Forest University School of Medicine, 1 Medical Center Blvd, Winston-Salem, NC, United States; Wake Forest Baptist Comprehensive Cancer Center, Wake Forest University School of Medicine, 1 Medical Center Blvd, Winston-Salem, NC, United States; Department of Radiation Oncology, Section on Radiation Biology, Wake Forest University School of Medicine, 1 Medical Center Blvd, Winston-Salem, NC, United States
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Sayin ES, Duffin J, Poublanc J, Venkatraghavan L, Mikulis DJ, Fisher JA, Sobczyk O. Determining the effects of elevated partial pressure of oxygen on hypercapnia-induced cerebrovascular reactivity. J Cereb Blood Flow Metab 2023; 43:2085-2095. [PMID: 37632334 PMCID: PMC10925865 DOI: 10.1177/0271678x231197000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 07/17/2023] [Accepted: 07/19/2023] [Indexed: 08/28/2023]
Abstract
Evaluation of cerebrovascular reactivity (CVR) to hypo- and hypercapnia is a valuable test for the assessment of vasodilatory reserve. While hypercapnia-induced CVR testing is usually performed at normoxia, mild hyperoxia may increase tolerability of hypercapnia by reducing the ventilatory distress. However, the effects of mild hyperoxia on CVR was unknown. We therefore recruited 21 patients with a range of steno-occlusive diseases and 12 healthy participants who underwent a standardized 13-minute step plus ramp CVR test with a carbon dioxide gas challenge at the subject's resting end-tidal partial pressure of oxygen or at mild hyperoxia (PetO2 = 150 mmHg) depending on to which group they were assigned. In 11 patients, the second CVR test was at normoxia to examine test-retest differences. CVR was defined as % Δ Signal/ΔPetCO2. We found that there was no significant difference between CVR test results conducted at normoxia and at mild hyperoxia for participants in Groups 1 and 2 for the step and ramp portion. We also found no difference between test and retest CVR at normoxia for patients with cerebrovascular pathology (Group 3) for step and ramp portion. We concluded normoxic CVR is repeatable, and that mild hyperoxia does not affect CVR.
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Affiliation(s)
- Ece Su Sayin
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - James Duffin
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Department of Anaesthesia and Pain Management, University Health Network, University of Toronto, Toronto, ON, Canada
| | - Julien Poublanc
- Joint Department of Medical Imaging and the Functional Neuroimaging Lab, University Health Network, Toronto, ON, Canada
| | - Lashmikumar Venkatraghavan
- Department of Anaesthesia and Pain Management, University Health Network, University of Toronto, Toronto, ON, Canada
| | - David John Mikulis
- Joint Department of Medical Imaging and the Functional Neuroimaging Lab, University Health Network, Toronto, ON, Canada
| | - Joseph Arnold Fisher
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Department of Anaesthesia and Pain Management, University Health Network, University of Toronto, Toronto, ON, Canada
| | - Olivia Sobczyk
- Department of Anaesthesia and Pain Management, University Health Network, University of Toronto, Toronto, ON, Canada
- Joint Department of Medical Imaging and the Functional Neuroimaging Lab, University Health Network, Toronto, ON, Canada
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Liu Y, Yuan F, Peng Z, Zhan Y, Lin J, Zhang R, Zhang J. Decrease in Cerebral Blood Flow after Reoxygenation Is Associated with Neurological Syndrome Sequelae and Blood Pressure. Brain Sci 2023; 13:1600. [PMID: 38002559 PMCID: PMC10669967 DOI: 10.3390/brainsci13111600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 10/30/2023] [Accepted: 11/06/2023] [Indexed: 11/26/2023] Open
Abstract
Changes in cerebral blood flow (CBF) and regulation of cerebral circulation occur at high altitude (HA). However, the changes in CBF and their associations with neurological syndrome sequelae and blood pressure after subjects return to the lowlands remain unclear. In this study, the subjects were 23 college students who were teaching at an altitude of 4300 m for 30 days. These subjects were studied before reaching the HA (Test 1), one week after returning to the lowlands (Test 2), and three months after returning to the lowlands (Test 3). Symptom scores for de-acclimatization syndrome were evaluated. Changes in CBF were measured using the magnetic resonance imaging arterial spin labeling (ASL) technique. Additionally, the velocity of CBF in the cerebral arteries was measured using a transcranial doppler (TCD). In Test 2 vs. Test 1, the peak systolic velocity and mean velocity in the basilar artery were significantly decreased. CBF exhibited significant decreases in the left putamen/cerebellum crus1/vermis and right thalamus/inferior temporal gyrus, while significant increases were observed in the left postcentral gyrus/precuneus and right middle cingulate gyrus/superior frontal gyrus. In Test 3 vs. Test 1, the basilar artery velocity returned to the baseline level, while CBF continued to decrease. The mean global CBF showed a decreasing trend from Test 1 to Test 3. Furthermore, the mean global CBF had a negative correlation with the systolic pressure, pulse pressure, and mean arterial pressure. The decrease in CBF after reoxygenation may underlie the neurological symptoms in subjects returning to the lowlands. Increased blood pressure could serve as a predictor of a decrease in CBF.
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Affiliation(s)
- Yanqiu Liu
- Institute of Brain Diseases and Cognition, School of Medicine, Xiamen University, Xiamen 361102, China
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Xiamen University, Xiamen 361102, China
| | - Fengjuan Yuan
- Institute of Brain Diseases and Cognition, School of Medicine, Xiamen University, Xiamen 361102, China
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Xiamen University, Xiamen 361102, China
| | - Zhongwei Peng
- Department of Neurology, Zhongshan Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen 361004, China
| | - Yadong Zhan
- Institute of Brain Diseases and Cognition, School of Medicine, Xiamen University, Xiamen 361102, China
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Xiamen University, Xiamen 361102, China
| | - Jianzhong Lin
- Department of Radiology, Zhongshan Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen 361004, China
| | - Ran Zhang
- Institute of Brain Diseases and Cognition, School of Medicine, Xiamen University, Xiamen 361102, China
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Xiamen University, Xiamen 361102, China
| | - Jiaxing Zhang
- Institute of Brain Diseases and Cognition, School of Medicine, Xiamen University, Xiamen 361102, China
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Xiamen University, Xiamen 361102, China
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10
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Benson EJ, Aronowitz DI, Forti RM, Lafontant A, Ranieri NR, Starr JP, Melchior RW, Lewis A, Jahnavi J, Breimann J, Yun B, Laurent GH, Lynch JM, White BR, Gaynor JW, Licht DJ, Yodh AG, Kilbaugh TJ, Mavroudis CD, Baker WB, Ko TS. Diffuse Optical Monitoring of Cerebral Hemodynamics and Oxygen Metabolism during and after Cardiopulmonary Bypass: Hematocrit Correction and Neurological Vulnerability. Metabolites 2023; 13:1153. [PMID: 37999249 PMCID: PMC10672802 DOI: 10.3390/metabo13111153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 11/07/2023] [Accepted: 11/07/2023] [Indexed: 11/25/2023] Open
Abstract
Cardiopulmonary bypass (CPB) provides cerebral oxygenation and blood flow (CBF) during neonatal congenital heart surgery, but the impacts of CPB on brain oxygen supply and metabolic demands are generally unknown. To elucidate this physiology, we used diffuse correlation spectroscopy and frequency-domain diffuse optical spectroscopy to continuously measure CBF, oxygen extraction fraction (OEF), and oxygen metabolism (CMRO2) in 27 neonatal swine before, during, and up to 24 h after CPB. Concurrently, we sampled cerebral microdialysis biomarkers of metabolic distress (lactate-pyruvate ratio) and injury (glycerol). We applied a novel theoretical approach to correct for hematocrit variation during optical quantification of CBF in vivo. Without correction, a mean (95% CI) +53% (42, 63) increase in hematocrit resulted in a physiologically improbable +58% (27, 90) increase in CMRO2 relative to baseline at CPB initiation; following correction, CMRO2 did not differ from baseline at this timepoint. After CPB initiation, OEF increased but CBF and CMRO2 decreased with CPB time; these temporal trends persisted for 0-8 h following CPB and coincided with a 48% (7, 90) elevation of glycerol. The temporal trends and glycerol elevation resolved by 8-24 h. The hematocrit correction improved quantification of cerebral physiologic trends that precede and coincide with neurological injury following CPB.
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Affiliation(s)
- Emilie J. Benson
- Department of Physics & Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA; (E.J.B.); (A.G.Y.)
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA; (R.M.F.); (A.L.); (N.R.R.); (J.J.); (J.B.); (B.Y.); (G.H.L.); (D.J.L.); (W.B.B.)
| | - Danielle I. Aronowitz
- Division of Cardiothoracic Surgery, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA; (D.I.A.); (J.W.G.); (C.D.M.)
| | - Rodrigo M. Forti
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA; (R.M.F.); (A.L.); (N.R.R.); (J.J.); (J.B.); (B.Y.); (G.H.L.); (D.J.L.); (W.B.B.)
| | - Alec Lafontant
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA; (R.M.F.); (A.L.); (N.R.R.); (J.J.); (J.B.); (B.Y.); (G.H.L.); (D.J.L.); (W.B.B.)
| | - Nicolina R. Ranieri
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA; (R.M.F.); (A.L.); (N.R.R.); (J.J.); (J.B.); (B.Y.); (G.H.L.); (D.J.L.); (W.B.B.)
| | - Jonathan P. Starr
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA; (J.P.S.); (T.J.K.)
| | - Richard W. Melchior
- Department of Perfusion Services, Cardiac Center, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA;
| | - Alistair Lewis
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jharna Jahnavi
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA; (R.M.F.); (A.L.); (N.R.R.); (J.J.); (J.B.); (B.Y.); (G.H.L.); (D.J.L.); (W.B.B.)
| | - Jake Breimann
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA; (R.M.F.); (A.L.); (N.R.R.); (J.J.); (J.B.); (B.Y.); (G.H.L.); (D.J.L.); (W.B.B.)
| | - Bohyun Yun
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA; (R.M.F.); (A.L.); (N.R.R.); (J.J.); (J.B.); (B.Y.); (G.H.L.); (D.J.L.); (W.B.B.)
| | - Gerard H. Laurent
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA; (R.M.F.); (A.L.); (N.R.R.); (J.J.); (J.B.); (B.Y.); (G.H.L.); (D.J.L.); (W.B.B.)
| | - Jennifer M. Lynch
- Division of Cardiothoracic Anesthesiology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA;
| | - Brian R. White
- Division of Cardiology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - J. William Gaynor
- Division of Cardiothoracic Surgery, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA; (D.I.A.); (J.W.G.); (C.D.M.)
| | - Daniel J. Licht
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA; (R.M.F.); (A.L.); (N.R.R.); (J.J.); (J.B.); (B.Y.); (G.H.L.); (D.J.L.); (W.B.B.)
| | - Arjun G. Yodh
- Department of Physics & Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA; (E.J.B.); (A.G.Y.)
| | - Todd J. Kilbaugh
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA; (J.P.S.); (T.J.K.)
| | - Constantine D. Mavroudis
- Division of Cardiothoracic Surgery, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA; (D.I.A.); (J.W.G.); (C.D.M.)
| | - Wesley B. Baker
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA; (R.M.F.); (A.L.); (N.R.R.); (J.J.); (J.B.); (B.Y.); (G.H.L.); (D.J.L.); (W.B.B.)
| | - Tiffany S. Ko
- Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA; (J.P.S.); (T.J.K.)
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11
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Ardellier FD, Baloglu S, Sokolska M, Noblet V, Lersy F, Collange O, Ferré JC, Maamar A, Carsin-Nicol B, Helms J, Schenck M, Khalil A, Gaudemer A, Caillard S, Pottecher J, Lefèbvre N, Zorn PE, Matthieu M, Brisset JC, Boulay C, Mutschler V, Hansmann Y, Mertes PM, Schneider F, Fafi-Kremer S, Ohana M, Meziani F, Meyer N, Yousry T, Anheim M, Cotton F, Jäger HR, Kremer S. Cerebral perfusion using ASL in patients with COVID-19 and neurological manifestations: A retrospective multicenter observational study. J Neuroradiol 2023; 50:470-481. [PMID: 36657613 PMCID: PMC9842391 DOI: 10.1016/j.neurad.2023.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 01/15/2023] [Accepted: 01/15/2023] [Indexed: 01/18/2023]
Abstract
BACKGROUND AND PURPOSE Cerebral hypoperfusion has been reported in patients with COVID-19 and neurological manifestations in small cohorts. We aimed to systematically assess changes in cerebral perfusion in a cohort of 59 of these patients, with or without abnormalities on morphological MRI sequences. METHODS Patients with biologically-confirmed COVID-19 and neurological manifestations undergoing a brain MRI with technically adequate arterial spin labeling (ASL) perfusion were included in this retrospective multicenter study. ASL maps were jointly reviewed by two readers blinded to clinical data. They assessed abnormal perfusion in four regions of interest in each brain hemisphere: frontal lobe, parietal lobe, posterior temporal lobe, and temporal pole extended to the amygdalo-hippocampal complex. RESULTS Fifty-nine patients (44 men (75%), mean age 61.2 years) were included. Most patients had a severe COVID-19, 57 (97%) needed oxygen therapy and 43 (73%) were hospitalized in intensive care unit at the time of MRI. Morphological brain MRI was abnormal in 44 (75%) patients. ASL perfusion was abnormal in 53 (90%) patients, and particularly in all patients with normal morphological MRI. Hypoperfusion occurred in 48 (81%) patients, mostly in temporal poles (52 (44%)) and frontal lobes (40 (34%)). Hyperperfusion occurred in 9 (15%) patients and was closely associated with post-contrast FLAIR leptomeningeal enhancement (100% [66.4%-100%] of hyperperfusion with enhancement versus 28.6% [16.6%-43.2%] without, p = 0.002). Studied clinical parameters (especially sedation) and other morphological MRI anomalies had no significant impact on perfusion anomalies. CONCLUSION Brain ASL perfusion showed hypoperfusion in more than 80% of patients with severe COVID-19, with or without visible lesion on conventional MRI abnormalities.
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Affiliation(s)
- François-Daniel Ardellier
- Service D'imagerie 2, Hôpital de Hautepierre, Hôpitaux Universitaires de Strasbourg, Strasbourg, France; Engineering science, computer science and imaging laboratory (ICube), Integrative Multimodal Imaging in Healthcare, UMR 7357, University of Strasbourg-CNRS, Strasbourg, France.
| | - Seyyid Baloglu
- Service D'imagerie 2, Hôpital de Hautepierre, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Magdalena Sokolska
- Department of Medical Physics and Biomedical Engineering, University College London Hospitals NHS Foundation Trust, 235 Euston Road, London NW1 2BU, United Kingdom; Neuroradiological Academic Unit, Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom
| | - Vincent Noblet
- Engineering science, computer science and imaging laboratory (ICube), Integrative Multimodal Imaging in Healthcare, UMR 7357, University of Strasbourg-CNRS, Strasbourg, France
| | - François Lersy
- Service D'imagerie 2, Hôpital de Hautepierre, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Olivier Collange
- Service d'Anesthésie-Réanimation, Nouvel Hôpital Civil, Hôpitaux universitaires de Strasbourg, Strasbourg, France
| | | | - Adel Maamar
- Medical Intensive Care Unit, CHU Rennes, Rennes, France
| | | | - Julie Helms
- Service de Médecine Intensive Réanimation, Nouvel Hôpital Civil, Hôpitaux Universitaires de Strasbourg, Strasbourg, France; Immuno-Rhumatologie Moléculaire, INSERM UMR S1109, LabEx TRANSPLANTEX, Centre de Recherche d'Immunologie et d'Hématologie, Faculté de Médecine, Fédération Hospitalo-Universitaire (FHU) OMICARE, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg (UNISTRA), Strasbourg, France
| | - Maleka Schenck
- Service de Médecine Intensive Réanimation, Hôpitaux universitaires de Strasbourg, Hautepierre, Strasbourg, France
| | - Antoine Khalil
- Department of Radiology, Assistance Publique-Hôpitaux de Paris (APHP), Denis Diderot University and Medical School, Bichat University Hospital, Paris, France
| | - Augustin Gaudemer
- Neuroradiology Unit, Department of Radiology, Assistance Publique-Hôpitaux de Paris (APHP), Bichat University Hospital, Paris, France
| | - Sophie Caillard
- Immuno-Rhumatologie Moléculaire, INSERM UMR S1109, LabEx TRANSPLANTEX, Centre de Recherche d'Immunologie et d'Hématologie, Faculté de Médecine, Fédération Hospitalo-Universitaire (FHU) OMICARE, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg (UNISTRA), Strasbourg, France; Nephrology and Transplantation department, Hôpitaux Universitaires de Strasbourg. Inserm UMR S1109, LabEx Transplantex, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg, Strasbourg, France
| | - Julien Pottecher
- Hôpital de Hautepierre, Service d'Anesthésie, Réanimation & Médecine Péri-Opératoire - Université de Strasbourg, Faculté de Médecine, FMTS, EA3072, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Nicolas Lefèbvre
- Service de Maladies Infectieuses, NHC, CHU de Strasbourg, Strasbourg, France
| | - Pierre-Emmanuel Zorn
- Hôpitaux Universitaires de Strasbourg, UCIEC, Pôle d'Imagerie, Strasbourg, France
| | - Muriel Matthieu
- Hôpitaux Universitaires de Strasbourg, UCIEC, Pôle d'Imagerie, Strasbourg, France
| | | | - Clotilde Boulay
- Service de Neurologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Véronique Mutschler
- Service de Neurologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Yves Hansmann
- Service de Maladies Infectieuses, NHC, CHU de Strasbourg, Strasbourg, France
| | - Paul-Michel Mertes
- Service d'Anesthésie-Réanimation, Nouvel Hôpital Civil, Hôpitaux universitaires de Strasbourg, Strasbourg, France
| | - Francis Schneider
- Service de Médecine Intensive Réanimation, Hôpitaux universitaires de Strasbourg, Hautepierre, Strasbourg, France
| | - Samira Fafi-Kremer
- Laboratoire de Virologie Médicale, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Mickael Ohana
- Radiology Department, Nouvel Hôpital Civil, Strasbourg University Hospital, Strasbourg, France
| | - Ferhat Meziani
- Service de Médecine Intensive Réanimation, Nouvel Hôpital Civil, Hôpitaux Universitaires de Strasbourg, Strasbourg, France; UMR 1260, Regenerative Nanomedicine (RNM), FMTS, INSERM (French National Institute of Health and Medical Research), Strasbourg, France
| | - Nicolas Meyer
- Service de Santé Publique, GMRC, CHU de Strasbourg, Strasbourg F-67091 , France
| | - Tarek Yousry
- Neuroradiological Academic Unit, Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom
| | - Mathieu Anheim
- Service de Neurologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France; INSERM-U964/CNRS-UMR7104/Université de Strasbourg, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France
| | - François Cotton
- MRI center, Centre Hospitalier Lyon Sud, Hospices Civils de Lyon, Lyon, France; CREATIS-LRMN, CNRS/UMR/5220-INSERM U630, Université Lyon 1, Villeurbanne, France
| | - Hans Rolf Jäger
- Neuroradiological Academic Unit, Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom
| | - Stéphane Kremer
- Service D'imagerie 2, Hôpital de Hautepierre, Hôpitaux Universitaires de Strasbourg, Strasbourg, France; Engineering science, computer science and imaging laboratory (ICube), Integrative Multimodal Imaging in Healthcare, UMR 7357, University of Strasbourg-CNRS, Strasbourg, France
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12
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Asehnoune K, Taccone FS, Singer M. High oxygen level in traumatic brain injury patients. Never ending story? Intensive Care Med 2022; 48:1772-1774. [PMID: 36264364 DOI: 10.1007/s00134-022-06903-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 09/28/2022] [Indexed: 11/29/2022]
Affiliation(s)
- Karim Asehnoune
- Department of Anaesthesia and Critical Care, CHU Nantes, Nantes Université, Hôtel Dieu, 44000, Nantes, France.
- Head, Anaesthesia and Surgical Critical Care Department, University Hospital of Nantes, Hôtel Dieu, 44000, Nantes, France.
- Lab Inserm, UMR 1064 CR2TI | Team 6, Nantes, France.
| | - Fabio S Taccone
- Department of Intensive Care, Hôpital Universitaire de Bruxelles (HUB), Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Mervyn Singer
- Mervyn Singer, Bloomsbury Institute of Intensive Care, University College London, London, UK
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13
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Healicon R, Rooney CHE, Ball V, Shinozaki A, Miller JJ, Smart S, Radford‐Smith D, Anthony D, Tyler DJ, Grist JT. Assessing the effect of anesthetic gas mixtures on hyperpolarized 13 C pyruvate metabolism in the rat brain. Magn Reson Med 2022; 88:1324-1332. [PMID: 35468245 PMCID: PMC9325476 DOI: 10.1002/mrm.29274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 03/11/2022] [Accepted: 03/31/2022] [Indexed: 11/09/2022]
Abstract
PURPOSE To determine the effect of altering anesthetic oxygen protocols on measurements of cerebral perfusion and metabolism in the rodent brain. METHODS Seven rats were anesthetized and underwent serial MRI scans with hyperpolarized [1-13 C]pyruvate and perfusion weighted imaging. The anesthetic carrier gas protocol used varied from 100:0% to 90:10% to 60:40% O2 :N2 O. Spectra were quantified with AMARES and perfusion imaging was processed using model-free deconvolution. A 1-way ANOVA was used to compare results across groups, with pairwise t tests performed with correction for multiple comparisons. Spearman's correlation analysis was performed between O2 % and MR measurements. RESULTS There was a significant increase in bicarbonate:total 13 C carbon and bicarbonate:13 C pyruvate when moving between 100:0 to 90:10 and 100:0 to 60:40 O2 :N2 O % (0.02 ± 0.01 vs. 0.019 ± 0.005 and 0.02 ± 0.01 vs. 0.05 ± 0.02, respectively) and (0.04 ± 0.01 vs. 0.03 ± 0.01 and 0.04 ± 0.01 vs. 0.08 ± 0.02, respectively). There was a significant difference in 13 C pyruvate time to peak when moving between 100:0 to 90:10 and 100:0 to 60:40 O2 :N2 O % (13 ± 2 vs. 10 ± 1 and 13 ± 2 vs. 7.5 ± 0.5 s, respectively) as well as significant differences in cerebral blood flow (CBF) between gas protocols. Significant correlations between bicarbonate:13 C pyruvate and gas protocol (ρ = -0.47), mean transit time and gas protocol (ρ = 0.41) and 13 C pyruvate time-to-peak and cerebral blood flow (ρ = -0.54) were also observed. CONCLUSIONS These results demonstrate that the detection and quantification of cerebral metabolism and perfusion is dependent on the oxygen protocol used in the anesthetized rodent brain.
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Affiliation(s)
- Richard Healicon
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUnited Kingdom
| | - Catriona H. E. Rooney
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUnited Kingdom
| | - Vicky Ball
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUnited Kingdom
| | - Ayaka Shinozaki
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUnited Kingdom
- Oxford Centre for Clinical Magnetic Resonance Research, Division of Cardiovascular Medicine, Radcliffe Department of MedicineUniversity of OxfordOxfordUnited Kingdom
| | - Jack J. Miller
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUnited Kingdom
- Oxford Centre for Clinical Magnetic Resonance Research, Division of Cardiovascular Medicine, Radcliffe Department of MedicineUniversity of OxfordOxfordUnited Kingdom
- Clarendon Laboratory, Department of PhysicsUniversity of OxfordOxfordUnited Kingdom
- The PET Centre and The MR Centre, Clinical MedicineAarhus University and Aarhus University HospitalAarhusDenmark
| | - Sean Smart
- Nuffield Department of Clinical NeurosciencesUniversity of OxfordOxfordUnited Kingdom
| | | | - Daniel Anthony
- Department of PharmacologyUniversity of OxfordOxfordUnited Kingdom
| | - Damian J. Tyler
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUnited Kingdom
- The PET Centre and The MR Centre, Clinical MedicineAarhus University and Aarhus University HospitalAarhusDenmark
| | - James T. Grist
- Department of Physiology, Anatomy, and GeneticsUniversity of OxfordOxfordUnited Kingdom
- The PET Centre and The MR Centre, Clinical MedicineAarhus University and Aarhus University HospitalAarhusDenmark
- Department of RadiologyOxford University HospitalsOxfordUnited Kingdom
- Institute of Cancer and Genomic SciencesUniversity of BirminghamBirminghamUnited Kingdom
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14
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Chen JJ, Uthayakumar B, Hyder F. Mapping oxidative metabolism in the human brain with calibrated fMRI in health and disease. J Cereb Blood Flow Metab 2022; 42:1139-1162. [PMID: 35296177 PMCID: PMC9207484 DOI: 10.1177/0271678x221077338] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Conventional functional MRI (fMRI) with blood-oxygenation level dependent (BOLD) contrast is an important tool for mapping human brain activity non-invasively. Recent interest in quantitative fMRI has renewed the importance of oxidative neuroenergetics as reflected by cerebral metabolic rate of oxygen consumption (CMRO2) to support brain function. Dynamic CMRO2 mapping by calibrated fMRI require multi-modal measurements of BOLD signal along with cerebral blood flow (CBF) and/or volume (CBV). In human subjects this "calibration" is typically performed using a gas mixture containing small amounts of carbon dioxide and/or oxygen-enriched medical air, which are thought to produce changes in CBF (and CBV) and BOLD signal with minimal or no CMRO2 changes. However non-human studies have demonstrated that the "calibration" can also be achieved without gases, revealing good agreement between CMRO2 changes and underlying neuronal activity (e.g., multi-unit activity and local field potential). Given the simpler set-up of gas-free calibrated fMRI, there is evidence of recent clinical applications for this less intrusive direction. This up-to-date review emphasizes technological advances for such translational gas-free calibrated fMRI experiments, also covering historical progression of the calibrated fMRI field that is impacting neurological and neurodegenerative investigations of the human brain.
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Affiliation(s)
- J Jean Chen
- Medical Biophysics, University of Toronto, Toronto, Canada.,Rotman Research Institute, Baycrest, Toronto, Canada
| | - Biranavan Uthayakumar
- Medical Biophysics, University of Toronto, Toronto, Canada.,Sunnybrook Research Institute, Toronto, Canada
| | - Fahmeed Hyder
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, Connecticut, USA.,Department of Radiology, Yale University, New Haven, Connecticut, USA.,Quantitative Neuroscience with Magnetic Resonance (QNMR) Research Program, Yale University, New Haven, Connecticut, USA.,Department of Biomedical Engineering, Yale University, New Haven, Connecticut, USA
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15
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The Impact of Short-Term Hyperoxia on Cerebral Metabolism: A Systematic Review and Meta-Analysis. Neurocrit Care 2022; 37:547-557. [PMID: 35641804 DOI: 10.1007/s12028-022-01529-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 04/26/2022] [Indexed: 10/18/2022]
Abstract
BACKGROUND Cerebral ischemia due to hypoxia is a major cause of secondary brain injury and is associated with higher morbidity and mortality in patients with acute brain injury. Hyperoxia could improve energetic dysfunction in the brain in this setting. Our objectives were to perform a systematic review and meta-analysis of the current literature and to assess the impact of normobaric hyperoxia on brain metabolism by using cerebral microdialysis. METHODS We searched Medline and Scopus, following the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement; we searched for retrospective and prospective observational studies, interventional studies, and randomized clinical trials that performed a hyperoxia challenge in patients with acute brain injury who were concomitantly monitored with cerebral microdialysis. This study was registered in PROSPERO (CRD420211295223). RESULTS We included a total of 17 studies, with a total of 311 patients. A statistically significant reduction in cerebral lactate values (pooled standardized mean difference [SMD] - 0.38 [- 0.53 to - 0.23]) and lactate to pyruvate ratio values (pooled SMD - 0.20 [- 0.35 to - 0.05]) was observed after hyperoxia. However, glucose levels (pooled SMD - 0.08 [- 0.23 to 0.08]) remained unchanged after hyperoxia. CONCLUSIONS Normobaric hyperoxia may improve cerebral metabolic disturbances in patients with acute brain injury. The clinical impact of such effects needs to be further elucidated.
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16
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Jiang D, Lu H. Cerebral oxygen extraction fraction MRI: Techniques and applications. Magn Reson Med 2022; 88:575-600. [PMID: 35510696 PMCID: PMC9233013 DOI: 10.1002/mrm.29272] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 03/20/2022] [Accepted: 03/29/2022] [Indexed: 12/20/2022]
Abstract
The human brain constitutes 2% of the body's total mass but uses 20% of the oxygen. The rate of the brain's oxygen utilization can be derived from a knowledge of cerebral blood flow and the oxygen extraction fraction (OEF). Therefore, OEF is a key physiological parameter of the brain's function and metabolism. OEF has been suggested to be a useful biomarker in a number of brain diseases. With recent advances in MRI techniques, several MRI-based methods have been developed to measure OEF in the human brain. These MRI OEF techniques are based on the T2 of blood, the blood signal phase, the magnetic susceptibility of blood-containing voxels, the effect of deoxyhemoglobin on signal behavior in extravascular tissue, and the calibration of the BOLD signal using gas inhalation. Compared to 15 O PET, which is considered the "gold standard" for OEF measurement, MRI-based techniques are non-invasive, radiation-free, and are more widely available. This article provides a review of these emerging MRI-based OEF techniques. We first briefly introduce the role of OEF in brain oxygen homeostasis. We then review the methodological aspects of different categories of MRI OEF techniques, including their signal mechanisms, acquisition methods, and data analyses. The strengths and limitations of the techniques are discussed. Finally, we review key applications of these techniques in physiological and pathological conditions.
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Affiliation(s)
- Dengrong Jiang
- The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Hanzhang Lu
- The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
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17
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Walton LR, Verber M, Lee SH, Chao THH, Wightman RM, Shih YYI. Simultaneous fMRI and fast-scan cyclic voltammetry bridges evoked oxygen and neurotransmitter dynamics across spatiotemporal scales. Neuroimage 2021; 244:118634. [PMID: 34624504 PMCID: PMC8667333 DOI: 10.1016/j.neuroimage.2021.118634] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 09/10/2021] [Accepted: 10/04/2021] [Indexed: 12/24/2022] Open
Abstract
The vascular contributions of neurotransmitters to the hemodynamic response are gaining more attention in neuroimaging studies, as many neurotransmitters are vasomodulatory. To date, well-established electrochemical techniques that detect neurotransmission in high magnetic field environments are limited. Here, we propose an experimental setting enabling simultaneous fast-scan cyclic voltammetry (FSCV) and blood oxygenation level-dependent functional magnetic imaging (BOLD fMRI) to measure both local tissue oxygen and dopamine responses, and global BOLD changes, respectively. By using MR-compatible materials and the proposed data acquisition schemes, FSCV detected physiological analyte concentrations with high temporal resolution and spatial specificity inside of a 9.4 T MRI bore. We found that tissue oxygen and BOLD correlate strongly, and brain regions that encode dopamine amplitude differences can be identified via modeling simultaneously acquired dopamine FSCV and BOLD fMRI time-courses. This technique provides complementary neurochemical and hemodynamic information and expands the scope of studying the influence of local neurotransmitter release over the entire brain.
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Affiliation(s)
- Lindsay R Walton
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America; Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America; Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America.
| | - Matthew Verber
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America; Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America; Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America
| | - Sung-Ho Lee
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America; Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America; Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America
| | - Tzu-Hao Harry Chao
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America; Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America; Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America
| | - R Mark Wightman
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America
| | - Yen-Yu Ian Shih
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America; Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America; Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America.
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18
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Association of Flow Rate of Prehospital Oxygen Administration and Clinical Outcomes in Severe Traumatic Brain Injury. J Clin Med 2021; 10:jcm10184097. [PMID: 34575206 PMCID: PMC8468196 DOI: 10.3390/jcm10184097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 09/06/2021] [Accepted: 09/08/2021] [Indexed: 11/28/2022] Open
Abstract
The goal of this study was to investigate the association of prehospital oxygen administration flow with clinical outcome in severe traumatic brain injury (TBI) patients. This was a cross-sectional observational study using an emergency medical services-assessed severe trauma database in South Korea. The sample included adult patients with severe blunt TBI without hypoxia who were treated by EMS providers in 2013 and 2015. Main exposure was prehospital oxygen administration flow rate (no oxygen, low-flow 1~5, mid-flow 6~14, high-flow 15 L/min). Primary outcome was in-hospital mortality. A total of 1842 patients with severe TBI were included. The number of patients with no oxygen, low-flow oxygen, mid-flow oxygen, high-flow oxygen was 244, 573, 607, and 418, respectively. Mortality of each group was 34.8%, 32.3%, 39.9%, and 41.1%, respectively. Compared with the no-oxygen group, adjusted odds (95% CI) for mortality in the low-, mid-, and high-flow oxygen groups were 0.86 (0.62–1.20), 1.15 (0.83–1.60), and 1.21 (0.83–1.73), respectively. In the interaction analysis, low-flow oxygen showed lower mortality when prehospital saturation was 94–98% (adjusted odds ratio (AOR): 0.80 (0.67–0.95)) and ≥99% (AOR: 0.69 (0.53–0.91)). High-flow oxygen showed higher mortality when prehospital oxygen saturation was ≥99% (AOR: 1.33 (1.01~1.74)). Prehospital low-flow oxygen administration was associated with lower in-hospital mortality compared with the no-oxygen group. High-flow administration showed higher mortality.
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19
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Bhattacharya I, Ramasawmy R, Javed A, Chen MY, Benkert T, Majeed W, Lederman RJ, Moss J, Balaban RS, Campbell-Washburn AE. Oxygen-enhanced functional lung imaging using a contemporary 0.55 T MRI system. NMR IN BIOMEDICINE 2021; 34:e4562. [PMID: 34080253 PMCID: PMC8377594 DOI: 10.1002/nbm.4562] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 04/30/2021] [Accepted: 05/04/2021] [Indexed: 05/14/2023]
Abstract
The purpose of this study was to evaluate oxygen-enhanced pulmonary imaging at 0.55 T with 3D stack-of-spirals ultrashort-TE (UTE) acquisition. Oxygen-enhanced pulmonary MRI offers the measurement of regional lung ventilation and perfusion using inhaled oxygen as a contrast agent. Low-field MRI systems equipped with contemporary hardware can provide high-quality structural lung imaging by virtue of the prolonged T2 *. Fortuitously, the T1 relaxivity of oxygen increases at lower field strengths, which is expected to improve the sensitivity of oxygen-enhanced lung MRI. We implemented a breath-held T1 -weighted 3D stack-of-spirals UTE acquisition with a 7 ms spiral-out readout. Measurement repeatability was assessed using five repetitions of oxygen-enhanced lung imaging in healthy volunteers (n = 7). The signal intensity at both normoxia and hyperoxia was strongly dependent on lung tissue density modulated by breath-hold volume during the five repetitions. A voxel-wise correction for lung tissue density improved the repeatability of percent signal enhancement maps (coefficient of variation = 34 ± 16%). Percent signal enhancement maps were compared in 15 healthy volunteers and 10 patients with lymphangioleiomyomatosis (LAM), a rare cystic disease known to reduce pulmonary function. We measured a mean percent signal enhancement of 9.0 ± 3.5% at 0.55 T in healthy volunteers, and reduced signal enhancement in patients with LAM (5.4 ± 4.8%, p = 0.02). The heterogeneity, estimated by the percent of lung volume exhibiting low enhancement, was significantly increased in patients with LAM compared with healthy volunteers (11.1 ± 6.0% versus 30.5 ± 13.1%, p = 0.01), illustrating the capability to measure regional functional deficits.
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Affiliation(s)
- Ipshita Bhattacharya
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda MD, USA 20892
| | - Rajiv Ramasawmy
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda MD, USA 20892
| | - Ahsan Javed
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda MD, USA 20892
| | - Marcus Y Chen
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda MD, USA 20892
| | - Thomas Benkert
- Siemens Healthcare GmbH, Henkestraße 127, 91052 Erlangen, Germany
| | - Waqas Majeed
- Siemens Medical Solutions USA Inc., 40 Liberty Boulevard, Malvern PA, 1935 USA
| | - Robert J Lederman
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda MD, USA 20892
| | - Joel Moss
- Pulmonary Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda MD, USA 20892
| | - Robert S Balaban
- Systems Biology Center, Division of Intramural Research, National Heart, Lung, and Blood I nstitute, National Institutes of Health, Bethesda MD, USA 20892
| | - Adrienne E Campbell-Washburn
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda MD, USA 20892
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20
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Champagne AA, Coverdale NS, Fernandez-Ruiz J, Mark CI, Cook DJ. Compromised resting cerebral metabolism after sport-related concussion: A calibrated MRI study. Brain Imaging Behav 2021; 15:133-146. [PMID: 32307673 DOI: 10.1007/s11682-019-00240-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Altered resting cerebral blood flow (CBF0) in the acute phase post-concussion may contribute to neurobehavioral deficiencies, often reported weeks after the injury. However, in addition to changes in CBF0, little is known about other physiological mechanisms that may be disturbed within the cerebrovasculature. The aim of this study was to assess whether changes in baseline perfusion following sport-related concussion (SRC) were co-localized with changes in cerebral metabolic demand. Forty-two subjects (15 SRC patients 8.0 ± 4.6 days post-injury and 27 age-matched healthy control athletes) were studied cross-sectionally. CBF0, cerebrovascular reactivity (CVR), resting oxygen extraction (OEF0) and cerebral metabolic rate of oxygen consumption (CMRO2|0) were measured using a combination of hypercapnic and hyperoxic breathing protocols, and the biophysical model developed in calibrated MRI. Blood oxygenation level dependent and perfusion data were acquired simultaneously using a dual-echo arterial spin labelling sequence. SRC patients showed significant decreases in CBF0 spread across the grey-matter (P < 0.05, corrected), and these differences were also confounded by the effects of baseline end-tidal CO2 (P < 0.0001). Lower perfusion was co-localized with reductions in regional CMRO2|0 (P = 0.006) post-SRC, despite finding no group-differences in OEF0 (P = 0.800). Higher CVR within voxels showing differences in CBF was also observed in the SRC group (P = 0.001), compared to controls. Reductions in metabolic demand despite no significant changes in OEF0 suggests that hypoperfusion post-SRC may reflect compromised metabolic function after the injury. These results provide novel insight about the possible pathophysiological mechanisms underlying concussion that may affect the clinical recovery of athletes after sport-related head injuries.
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Affiliation(s)
- Allen A Champagne
- Centre for Neuroscience Studies, Queen's University, Kingston, ON, K7L 3N6, Canada
| | - Nicole S Coverdale
- Centre for Neuroscience Studies, Queen's University, Kingston, ON, K7L 3N6, Canada
| | - Juan Fernandez-Ruiz
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, 04510, Ciudad de México, Mexico
| | - Clarisse I Mark
- Centre for Neuroscience Studies, Queen's University, Kingston, ON, K7L 3N6, Canada
| | - Douglas J Cook
- Centre for Neuroscience Studies, Queen's University, Kingston, ON, K7L 3N6, Canada.
- Department of Surgery, Queen's University, Room 232, 18 Stuart St., Kingston, ON, K7L 3N6, Canada.
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21
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Champagne AA, Bhogal AA. Insights Into Cerebral Tissue-Specific Response to Respiratory Challenges at 7T: Evidence for Combined Blood Flow and CO 2-Mediated Effects. Front Physiol 2021; 12:601369. [PMID: 33584344 PMCID: PMC7876301 DOI: 10.3389/fphys.2021.601369] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 01/06/2021] [Indexed: 11/16/2022] Open
Abstract
Cerebrovascular reactivity (CVR) mapping is finding increasing clinical applications as a non-invasive probe for vascular health. Further analysis extracting temporal delay information from the CVR response provide additional insight that reflect arterial transit time, blood redistribution, and vascular response speed. Untangling these factors can help better understand the (patho)physiology and improve diagnosis/prognosis associated with vascular impairments. Here, we use hypercapnic (HC) and hyperoxic (HO) challenges to gather insight about factors driving temporal delays between gray-matter (GM) and white-matter (WM). Blood Oxygen Level Dependent (BOLD) datasets were acquired at 7T in nine healthy subjects throughout BLOCK- and RAMP-HC paradigms. In a subset of seven participants, a combined HC+HO block, referred as the “BOOST” protocol, was also acquired. Tissue-based differences in Rapid Interpolation at Progressive Time Delays (RIPTiDe) were compared across stimulus to explore dynamic (BLOCK-HC) versus progressive (RAMP-HC) changes in CO2, as well as the effect of bolus arrival time on CVR delays (BLOCK-HC versus BOOST). While GM delays were similar between the BLOCK- (21.80 ± 10.17 s) and RAMP-HC (24.29 ± 14.64 s), longer WM lag times were observed during the RAMP-HC (42.66 ± 17.79 s), compared to the BLOCK-HC (34.15 ± 10.72 s), suggesting that the progressive stimulus may predispose WM vasculature to longer delays due to the smaller arterial content of CO2 delivered to WM tissues, which in turn, decreases intravascular CO2 gradients modulating CO2 diffusion into WM tissues. This was supported by a maintained ∼10 s offset in GM (11.66 ± 9.54 s) versus WM (21.40 ± 11.17 s) BOOST-delays with respect to the BLOCK-HC, suggesting that the vasoactive effect of CO2 remains constant and that shortening of BOOST delays was be driven by blood arrival reflected through the non-vasodilatory HO contrast. These findings support that differences in temporal and magnitude aspects of CVR between vascular networks reflect a component of CO2 sensitivity, in addition to redistribution and steal blood flow effects. Moreover, these results emphasize that the addition of a BOOST paradigm may provide clinical insights into whether vascular diseases causing changes in CVR do so by way of severe blood flow redistribution effects, alterations in vascular properties associated with CO2 diffusion, or changes in blood arrival time.
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Affiliation(s)
- Allen A Champagne
- Centre for Neuroscience Studies, Queen's University, Kingston, ON, Canada.,School of Medicine, Queen's University, Kingston, ON, Canada
| | - Alex A Bhogal
- Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands
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22
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Baekgaard JS, Abback PS, Boubaya M, Moyer JD, Garrigue D, Raux M, Champigneulle B, Dubreuil G, Pottecher J, Laitselart P, Laloum F, Bloch-Queyrat C, Adnet F, Paugam-Burtz C. Early hyperoxemia is associated with lower adjusted mortality after severe trauma: results from a French registry. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2020; 24:604. [PMID: 33046127 PMCID: PMC7549241 DOI: 10.1186/s13054-020-03274-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 09/04/2020] [Indexed: 01/19/2023]
Abstract
Background Hyperoxemia has been associated with increased mortality in critically ill patients, but little is known about its effect in trauma patients. The objective of this study was to assess the association between early hyperoxemia and in-hospital mortality after severe trauma. We hypothesized that a PaO2 ≥ 150 mmHg on admission was associated with increased in-hospital mortality. Methods Using data issued from a multicenter prospective trauma registry in France, we included trauma patients managed by the emergency medical services between May 2016 and March 2019 and admitted to a level I trauma center. Early hyperoxemia was defined as an arterial oxygen tension (PaO2) above 150 mmHg measured on hospital admission. In-hospital mortality was compared between normoxemic (150 > PaO2 ≥ 60 mmHg) and hyperoxemic patients using a propensity-score model with predetermined variables (gender, age, prehospital heart rate and systolic blood pressure, temperature, hemoglobin and arterial lactate, use of mechanical ventilation, presence of traumatic brain injury (TBI), initial Glasgow Coma Scale score, Injury Severity Score (ISS), American Society of Anesthesiologists physical health class > I, and presence of hemorrhagic shock). Results A total of 5912 patients were analyzed. The median age was 39 [26–55] years and 78% were male. More than half (53%) of the patients had an ISS above 15, and 32% had traumatic brain injury. On univariate analysis, the in-hospital mortality was higher in hyperoxemic patients compared to normoxemic patients (12% versus 9%, p < 0.0001). However, after propensity score matching, we found a significantly lower in-hospital mortality in hyperoxemic patients compared to normoxemic patients (OR 0.59 [0.50–0.70], p < 0.0001). Conclusion In this large observational study, early hyperoxemia in trauma patients was associated with reduced adjusted in-hospital mortality. This result contrasts the unadjusted in-hospital mortality as well as numerous other findings reported in acutely and critically ill patients. The study calls for a randomized clinical trial to further investigate this association.
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Affiliation(s)
- Josefine S Baekgaard
- Urgences et Samu 93, AP-HP, Avicenne Hospital, Inserm U942, 93000, Bobigny, France. .,Department of Anesthesia, Section 4231, Centre of Head and Orthopedics, Rigshospitalet, University of Copenhagen, Juliane Maries Vej 10, DK-2100, Copenhagen, Denmark.
| | - Paer-Selim Abback
- Department of Anesthesia and Critical Care, Beaujon Hospital, AP-HP, University of Paris, Paris, France
| | | | - Jean-Denis Moyer
- Department of Anesthesia and Critical Care, Beaujon Hospital, AP-HP, University of Paris, Paris, France
| | - Delphine Garrigue
- Department of Anesthesia and Critical Care, CHU de Lille, Lille, France
| | - Mathieu Raux
- Sorbonne Université, INSERM, UMRS1158 Neurophysiologie Respiratoire Expérimentale et Clinique; AP-HP Groupe Hospitalier Universitaire APHP-Sorbonne Université, site Pitié-Salpêtrière, Département d'Anesthésie Réanimation, F-75013, Paris, France
| | - Benoit Champigneulle
- Surgical Intensive Care Unit, Georges Pompidou European Hospital, AP-HP, Paris, France
| | - Guillaume Dubreuil
- Department of Anesthesia and Critical Care, AP-HP, Bicêtre Hospital, Paris, France
| | - Julien Pottecher
- Department of Anesthesia and Surgical Critical Care, Strasbourg University Hospital, Strasbourg, France
| | | | - Fleur Laloum
- Department of Anesthesia and Critical Care, University Hospital of Reims, Reims, France
| | | | - Frédéric Adnet
- Urgences et Samu 93, AP-HP, Avicenne Hospital, Inserm U942, 93000, Bobigny, France
| | - Catherine Paugam-Burtz
- Department of Anesthesia and Critical Care, Beaujon Hospital, AP-HP, University of Paris, Paris, France
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23
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Lee H, Wehrli FW. Venous cerebral blood volume mapping in the whole brain using venous-spin-labeled 3D turbo spin echo. Magn Reson Med 2020; 84:1991-2003. [PMID: 32243708 DOI: 10.1002/mrm.28262] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 02/27/2020] [Accepted: 02/29/2020] [Indexed: 11/12/2022]
Abstract
PURPOSE Venous cerebral blood volume (CBVv ) is a major contributor to BOLD contrast, and therefore is an important parameter for understanding the underlying mechanism. Here, we propose a velocity-selective venous spin labeling (VS-VSL)-prepared 3D turbo spin echo pulse sequence for whole-brain baseline CBVv mapping. METHODS Unlike previous CBVv measurement techniques that exploit the interrelationship between BOLD signals and CBVv , in the proposed VS-VSL technique both arterial blood and cerebrospinal fluid (CSF) signals were suppressed before the VS pulse train for exclusive labeling of venous blood, while a single-slab 3D turbo spin echo readout was used because of its relative immunity to magnetic field variations. Furthermore, two approximations were made to the VS-VSL signal model for simplified derivation of CBVv . In vivo studies were performed at 3T field strength in 8 healthy subjects. The performance of the proposed VS-VSL method in baseline CBVv estimation was first evaluated in comparison to the existing, hyperoxia-based method. Then, data were also acquired using VS-VSL under hypercapnic and hyperoxic gas breathing challenges for further validation of the technique. RESULTS The proposed technique yielded physiologically plausible baseline CBVv values, and when compared with the hyperoxia-based method, showed no statistical difference. Furthermore, data acquired using VS-VSL yielded average CBVv of 2.89%/1.78%, 3.71%/2.29%, and 2.88%/1.76% for baseline, hypercapnia, and hyperoxia, respectively, in gray/white matter regions. As expected, hyperoxia had negligible effect (P > .8), whereas hypercapnia demonstrated vasodilation (P << .01). CONCLUSION Upon further validation of the quantification model, the method is expected to have merit for 3D CBVv measurements across the entire brain.
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Affiliation(s)
- Hyunyeol Lee
- Laboratory for Structural, Physiologic, and Functional Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Felix W Wehrli
- Laboratory for Structural, Physiologic, and Functional Imaging, Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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24
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Champagne AA, Coverdale NS, Germuska M, Bhogal AA, Cook DJ. Changes in volumetric and metabolic parameters relate to differences in exposure to sub-concussive head impacts. J Cereb Blood Flow Metab 2020; 40:1453-1467. [PMID: 31307284 PMCID: PMC7308522 DOI: 10.1177/0271678x19862861] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 06/11/2019] [Indexed: 01/15/2023]
Abstract
Structural and calibrated magnetic resonance imaging data were acquired on 44 collegiate football players prior to the season (PRE), following the first four weeks in-season (PTC) and one month after the last game (POST). Exposure data collected from g-Force accelerometers mounted to the helmet of each player were used to split participants into HIGH (N = 22) and LOW (N = 22) exposure groups, based on the frequency of impacts sustained by each athlete. Significant decreases in grey-matter volume specific to the HIGH group were documented at POST (P = 0.009), compared to baseline. Changes in resting cerebral blood flow (CBF0), corrected for partial volume effects, were observed within the HIGH group, throughout the season (P < 0.0001), suggesting that alterations in perfusion may follow exposure to sub-concussive collisions. Co-localized significant increases in cerebral metabolic rate of oxygen consumption (CMRO2|0) mid-season were also documented in the HIGH group, with respect to both PRE- and POST values. No physiological changes were observed in the LOW group. Therefore, cerebral metabolic demand may be elevated in players with greater exposure to head impacts. These results provide novel insight into the effects of sub-concussive collisions on brain structure and cerebrovascular physiology and emphasize the importance of multi-modal imaging for a complete characterization of cerebral health.
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Affiliation(s)
- Allen A Champagne
- Centre for Neuroscience Studies, Queen’s
University, Kingston, ON, Canada
| | - Nicole S Coverdale
- Centre for Neuroscience Studies, Queen’s
University, Kingston, ON, Canada
| | - Mike Germuska
- Cardiff University Brain Research
Imaging Center, Cardiff University, Cardiff, UK
| | - Alex A Bhogal
- Department of Radiology, University
Medical Center Utrecht, Utrecht, The Netherlands
| | - Douglas J Cook
- Centre for Neuroscience Studies, Queen’s
University, Kingston, ON, Canada
- Department of Surgery, Queen’s
University, Kingston, ON, Canada
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25
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Englund EK, Fernández-Seara MA, Rodríguez-Soto AE, Lee H, Rodgers ZB, Vidorreta M, Detre JA, Wehrli FW. Calibrated fMRI for dynamic mapping of CMRO 2 responses using MR-based measurements of whole-brain venous oxygen saturation. J Cereb Blood Flow Metab 2020; 40:1501-1516. [PMID: 31394960 PMCID: PMC7308517 DOI: 10.1177/0271678x19867276] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Functional MRI (fMRI) can identify active foci in response to stimuli through BOLD signal fluctuations, which represent a complex interplay between blood flow and cerebral metabolic rate of oxygen (CMRO2) changes. Calibrated fMRI can disentangle the underlying contributions, allowing quantification of the CMRO2 response. Here, whole-brain venous oxygen saturation (Yv) was computed alongside ASL-measured CBF and BOLD-weighted data to derive the calibration constant, M, using the proposed Yv-based calibration. Data were collected from 10 subjects at 3T with a three-part interleaved sequence comprising background-suppressed 3D-pCASL, 2D BOLD-weighted, and single-slice dual-echo GRE (to measure Yv via susceptometry-based oximetry) acquisitions while subjects breathed normocapnic/normoxic, hyperoxic, and hypercapnic gases, and during a motor task. M was computed via Yv-based calibration from both hypercapnia and hyperoxia stimulus data, and results were compared to conventional hypercapnia or hyperoxia calibration methods. Mean M in gray matter did not significantly differ between calibration methods, ranging from 8.5 ± 2.8% (conventional hyperoxia calibration) to 11.7 ± 4.5% (Yv-based calibration in response to hyperoxia), with hypercapnia-based M values between (p = 0.56). Relative CMRO2 changes from finger tapping were computed from each M map. CMRO2 increased by ∼20% in the motor cortex, and good agreement was observed between the conventional and proposed calibration methods.
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Affiliation(s)
- Erin K Englund
- Laboratory for Structural, Physiologic and Functional Imaging (LSPFI), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Ana E Rodríguez-Soto
- Laboratory for Structural, Physiologic and Functional Imaging (LSPFI), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Hyunyeol Lee
- Laboratory for Structural, Physiologic and Functional Imaging (LSPFI), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Zachary B Rodgers
- Laboratory for Structural, Physiologic and Functional Imaging (LSPFI), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA.,Department of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Marta Vidorreta
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA.,Siemens Healthineers, Madrid, Spain
| | - John A Detre
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Felix W Wehrli
- Laboratory for Structural, Physiologic and Functional Imaging (LSPFI), Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
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26
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Ma Y, Mazerolle EL, Cho J, Sun H, Wang Y, Pike GB. Quantification of brain oxygen extraction fraction using QSM and a hyperoxic challenge. Magn Reson Med 2020; 84:3271-3285. [DOI: 10.1002/mrm.28390] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 05/19/2020] [Accepted: 06/01/2020] [Indexed: 12/24/2022]
Affiliation(s)
- Yuhan Ma
- Department of Biomedical Engineering and McConnell Brain Imaging Centre McGill University Montréal Quebec Canada
| | - Erin L. Mazerolle
- Department of Radiology and Hotchkiss Brain Institute University of Calgary Calgary Alberta Canada
| | - Junghun Cho
- Department of Biomedical Engineering Cornell University Ithaca New York USA
| | - Hongfu Sun
- Department of Radiology and Hotchkiss Brain Institute University of Calgary Calgary Alberta Canada
- School of Information Technology and Electrical Engineering University of Queensland Brisbane Australia
| | - Yi Wang
- Department of Biomedical Engineering Cornell University Ithaca New York USA
- Department of Radiology Weill Cornell Medical College New York New York USA
| | - G. Bruce Pike
- Department of Biomedical Engineering and McConnell Brain Imaging Centre McGill University Montréal Quebec Canada
- Department of Radiology and Hotchkiss Brain Institute University of Calgary Calgary Alberta Canada
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27
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Perioperative Hyperoxyphobia: Justified or Not? Benefits and Harms of Hyperoxia during Surgery. J Clin Med 2020; 9:jcm9030642. [PMID: 32121051 PMCID: PMC7141263 DOI: 10.3390/jcm9030642] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 02/18/2020] [Accepted: 02/26/2020] [Indexed: 12/12/2022] Open
Abstract
The use of an inspiratory oxygen fraction of 0.80 during surgery is a topic of ongoing debate. Opponents claim that increased oxidative stress, atelectasis, and impaired oxygen delivery due to hyperoxic vasoconstriction are detrimental. Proponents point to the beneficial effects on the incidence of surgical site infections and postoperative nausea and vomiting. Also, hyperoxygenation is thought to extend the safety margin in case of acute intraoperative emergencies. This review provides a comprehensive risk-benefit analysis for the use of perioperative hyperoxia in noncritically ill adults based on clinical evidence and supported by physiological deduction where needed. Data from the field of hyperbaric medicine, as a model of extreme hyperoxygenation, are extrapolated to the perioperative setting. We ultimately conclude that current evidence is in favour of hyperoxia in noncritically ill intubated adult surgical patients.
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Zhilyaev SY, Platonova TF, Alekseeva OS, Nikitina ER, Demchenko IT. Adaptive Mechanisms of Baroreflectory Regulation of the Cardiovascular System in Extreme Hyperoxia. J EVOL BIOCHEM PHYS+ 2019. [DOI: 10.1134/s002209301905003x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Voluntary exercise increases brain tissue oxygenation and spatially homogenizes oxygen delivery in a mouse model of Alzheimer's disease. Neurobiol Aging 2019; 88:11-23. [PMID: 31866158 DOI: 10.1016/j.neurobiolaging.2019.11.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 11/20/2019] [Accepted: 11/22/2019] [Indexed: 11/21/2022]
Abstract
Although vascular contributions to dementia and Alzheimer's disease (AD) are increasingly recognized, the potential brain oxygenation disruption associated with AD and whether preventive strategies to maintain tissue oxygenation are beneficial remain largely unknown. This study aimed to examine (1) whether brain oxygenation is compromised by the onset of AD and (2) how voluntary exercise modulates the influence of AD on brain oxygenation. In vivo 2-photon phosphorescence lifetime microscopy was used to investigate local changes of brain tissue oxygenation with the progression of AD and its modulation by exercise in the barrel cortex of awake transgenic AD mice. Our results show that cerebral tissue oxygen partial pressure (PO2) decreased with the onset of AD. Reduced PO2 was associated with the presence of small near-hypoxic areas, an increased oxygen extraction fraction, and reduced blood flow, observations that were all reverted by exercise. AD and age also increased the spatial heterogeneity of brain tissue oxygenation, which was normalized by exercise. Ex vivo staining also showed fewer amyloid-β (Aβ) deposits in the exercise group. Finally, we observed correlations between voluntary running distance and cerebral tissue oxygenation/blood flow, suggesting a dose-response relationship of exercise on the brain. Overall, this study suggests that compromised brain oxygenation is an indicator of the onset of AD, with the emergence of potential deleterious mechanisms associated with hypoxia. Furthermore, voluntary exercise enhanced the neurovascular oxygenation process, potentially offering a means to delay these changes.
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Thiel S, Gaisl T, Lettau F, Boss A, Winklhofer S, Kohler M, Rossi C. Impact of hypertension on cerebral microvascular structure in CPAP-treated obstructive sleep apnoea patients: a diffusion magnetic resonance imaging study. Neuroradiology 2019; 61:1437-1445. [PMID: 31529145 DOI: 10.1007/s00234-019-02292-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 09/05/2019] [Indexed: 11/28/2022]
Abstract
PURPOSE Obstructive sleep apnoea (OSA) is a highly prevalent sleep-related breathing disorder associated with hypertension, impaired peripheral vascular function and an increased risk of stroke. Evidence suggests that abnormalities of the cerebral microcirculation, such as capillary rarefication, may be present in these patients. We evaluated whether the presence of hypertension may affect the cerebral capillary architecture and function assessed by Intravoxel Incoherent Motion (IVIM) magnetic resonance imaging (MRI) in patients with continuous positive airway pressure (CPAP)-treated OSA. METHODS Forty-one patients (88% male, mean age 57 ± 10 years) with moderate-to-severe OSA were selected and divided into two groups (normotensive vs. hypertensive). All hypertensive OSA patients were adherent with their antihypertensive medication. Cerebral microvascular structure was assessed in grey (GM) and white matter (WM) using an echo-planar diffusion imaging sequence with 14 different b values. A step-wise IVIM analysis algorithm was applied to compute true diffusion (D), perfusion fraction (f) and pseudo-diffusion (D*) values. Group comparisons were performed with the Wilcoxon-Mann-Whitney-Test. Regression analysis was adjusted for age. RESULTS Diffusion- and perfusion-related indexes in middle-aged OSA normotensive patients were quantified in both tissue types (D [10-3 mm2/s]: GM = 0.83 ± 0.03; WM = 0.72 ± 0.03; f (%) GM = 0.09 ± 0.01; WM = 0.06 ± 0.01; D* [10-3 mm2/s]: GM = 7.72 ± 0.89; WM = 7.38 ± 0.98). In the examined tissue types, hypertension did not result in changes on the estimated MRI IVIM index values. CONCLUSION Based on IVIM analysis, cerebral microvascular structure and function showed no difference between hypertensive and normotensive patients with moderate-to-severe OSA treated with CPAP. Treatment adherence with antihypertensive drug regime and, in turn, controlled hypertension seems not to affect microvascular structure and perfusion of the brain. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT02493673.
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Affiliation(s)
- Sira Thiel
- Department of Pulmonology and Sleep Disorders Centre, University Hospital Zurich, Raemistrasse 100, Zurich, Switzerland.
| | - Thomas Gaisl
- Department of Pulmonology and Sleep Disorders Centre, University Hospital Zurich, Raemistrasse 100, Zurich, Switzerland
| | - Franziska Lettau
- Department of Pulmonology and Sleep Disorders Centre, University Hospital Zurich, Raemistrasse 100, Zurich, Switzerland
| | - Andreas Boss
- Department of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich, Switzerland
| | | | - Malcolm Kohler
- Department of Pulmonology and Sleep Disorders Centre, University Hospital Zurich, Raemistrasse 100, Zurich, Switzerland.,Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Cristina Rossi
- Department of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich, Switzerland
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Non-BOLD contrast for laminar fMRI in humans: CBF, CBV, and CMRO2. Neuroimage 2019; 197:742-760. [DOI: 10.1016/j.neuroimage.2017.07.041] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 07/10/2017] [Accepted: 07/19/2017] [Indexed: 12/22/2022] Open
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Champagne AA, Coverdale NS, Germuska M, Cook DJ. Multi-parametric analysis reveals metabolic and vascular effects driving differences in BOLD-based cerebrovascular reactivity associated with a history of sport concussion. Brain Inj 2019; 33:1479-1489. [PMID: 31354054 PMCID: PMC7115911 DOI: 10.1080/02699052.2019.1644375] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 07/12/2019] [Indexed: 12/19/2022]
Abstract
Objective: Identify alterations in cerebrovascular reactivity (CVR) based on the history of sport-related concussion (SRC). Further explore possible mechanisms underlying differences in vascular physiology using hemodynamic parameters modeled using calibrated magnetic resonance imaging (MRI). Method: End-tidal targeting and dual-echo MRI were combined to probe hypercapnic and hyperoxic challenges in athletes with (n = 32) and without (n = 31) a history of SRC. Concurrent blood oxygenation level dependent (BOLD) and arterial spin labeling (ASL) data were used to compute BOLD-CVR, ASL-CVR, and other physiological parameters including resting oxygen extraction fraction (OEF0) and cerebral blood volume (CBV0). Multiple linear and logistic regressions were then used to identify dominant parameters driving group-differences in BOLD-CVR. Results: Robust evidence for elevated BOLD-CVR were found in athletes with SRC history spreading over parts of the cortical hemispheres. Follow-up analyses showed co-localized differences in ASL-CVR (representing modulation of cerebral blood flow) and hemodynamic factors representing static vascular (i.e., CBV0) and metabolic (i.e., OEF0) effects suggesting that group-based differences in BOLD-CVR may be driven by a mixed effect from factors with vascular and metabolic origins. Conclusion: These results emphasize that while BOLD-CVR offers promises as a surrogate non-specific biomarker for cerebrovascular health following SRC, multiple hemodynamic parameters can affect its relative measurements. Abbreviations: [dHb]: concentration of deoxyhemoglobin; AFNI: Analysis of Functional NeuroImages ( https://afni.nimh.nih.gov ); ASL: arterial spin labeling; BIG: position group: defensive and offensive linemen; BIG-SKILL: position group: full backs, linebackers, running backs, tight-ends; BOLD: blood oxygen level dependent; CBF: cerebral blood flow; CMRO2: cerebral metabolic rate of oxygen consumption; CTL: group of control subjects; CVR: cerebrovascular reactivity; fMRI: functional magnetic resonance imaging; FSL: FMRIB software library ( https://fsl.fmrib.ox.ac.uk/fsl/fslwiki/ ); HC: hypercapnia; HO: hyperoxia; HX: group with history of concussion; M: maximal theoretical BOLD signal upon complete removal of venous dHb; pCASL: pseudo-continuous arterial spin labeling; PETCO2: end-tidal carbon dioxide; PETO2: end-tidal oxygen; SCAT: sport-concussion assessment tool; SKILL: position group: defensive backs, kickers, quarterbacks, safeties, wide-receivers; SRC: sport-related concussion.
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Affiliation(s)
- Allen A. Champagne
- Centre for Neuroscience Studies, Queen’s University, Kingston, ON, Canada
| | | | - Michael Germuska
- Cardiff University Brain Research Imaging Center, Cardiff University, Cardiff, United Kingdom
| | - Douglas J. Cook
- Centre for Neuroscience Studies, Queen’s University, Kingston, ON, Canada
- Department of Surgery, Queen’s University, Kingston, ON, Canada
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López HV, Vivas MF, Ruiz RN, Martínez JR, Navaridas BGV, Villa MG, Lázaro CL, Rubio RJ, Ortiz AM, Lacal LA, Diéguez AM. Association between post-procedural hyperoxia and poor functional outcome after mechanical thrombectomy for ischemic stroke: an observational study. Ann Intensive Care 2019; 9:59. [PMID: 31127402 PMCID: PMC6534627 DOI: 10.1186/s13613-019-0533-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 05/15/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND The actual effects of oxygen therapy on patients who have suffered a stroke are still unknown, and its recommendation as a routine measure in emergency services remains controversial. The aim of this study is to determine the effect of hyperoxia in functional recovery in patients with ischemic stroke who underwent intra-arterial mechanical thrombectomy (IAMT). METHODS A prospective observational cohort study that included all adult patients consecutively admitted to the intensive care unit (ICU) due to an ischemic stroke in the anterior cerebral circulation and following an IAMT intervention, between 2010 and 2015. All patients were intubated and connected to mechanical ventilation for the intra-arterial therapy, receiving supplementary oxygen to achieve saturations above 94%. Two groups were established regarding oxygen partial pressure (paO2) reached. It was based on a single ICU admission blood gas analysis. The hyperoxia group was defined as paO2 > 120 mmHg. We measured functional recovery in each of the groups according to the modified Rankin scale after 90 days. RESULTS For the analysis, a total of 333 patients were included. High levels of paO2 were mostly related to higher scores in modified Rankin scale (mRS) after 90 days. There were 60.6% cases with mRS ≥ 4 and 70.6% with mRS ≥ 3 in the hyperoxia group, compared to 43.0% and 56.1% in the paO2 ≤ 120 group, p < 0.01, respectively. Mortality was higher in the hyperoxia group, 28.6% vs 18.7%, p = 0.04. After regression adjustment by confounding factors, poor functional outcome was still significantly higher in the hyperoxia group, for both mRS ≥ 4 and mRS ≥ 3: OR 2.2.7, IC 95%, 1.22-4.23, p = 0.01 and OR 2.07, IC 95%, 1.05-4.029, p = 0.04, respectively. Both the National Institute of Health Stroke Scale Score (NIHSS) values at 24 h after the IAMT and the days of ICU stay were significantly higher in the hyperoxia group. CONCLUSIONS In patients with ischemic stroke in the anterior cerebral circulation treated with IAMT, we found an association between admission PaO2 > 120 mmHg and worse functional outcome 90 days after ischemic stroke, but this association needs further confirmation by other studies.
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Affiliation(s)
- Héctor Vargas López
- Department of Intensive Care, Virgen de la Arrixaca, Clinical University Hospital, Murcia, Spain.
| | - Miguel Fernández Vivas
- Department of Intensive Care, Virgen de la Arrixaca, Clinical University Hospital, Murcia, Spain
| | - Rafael Núñez Ruiz
- Department of Intensive Care, Virgen de la Arrixaca, Clinical University Hospital, Murcia, Spain
| | - José Ros Martínez
- Department of Intensive Care, Virgen de la Arrixaca, Clinical University Hospital, Murcia, Spain
| | | | - Manuel García Villa
- Department of Intensive Care, Virgen de la Arrixaca, Clinical University Hospital, Murcia, Spain
| | - Cristina Llamas Lázaro
- Department of Intensive Care, Virgen de la Arrixaca, Clinical University Hospital, Murcia, Spain
| | - Rubén Jara Rubio
- Department of Intensive Care, Virgen de la Arrixaca, Clinical University Hospital, Murcia, Spain
| | - Ana Morales Ortiz
- Department of Neurology, Biomedical Research Institute of Murcia (IMIB), Virgen de la Arrixaca, Clinical University Hospital, Murcia, Spain
| | - Laura Albert Lacal
- Department of Neurology, Biomedical Research Institute of Murcia (IMIB), Virgen de la Arrixaca, Clinical University Hospital, Murcia, Spain
| | - Antonio Moreno Diéguez
- Department of Neuroradiology, Virgen de la Arrixaca, Clinical University Hospital, Murcia, Spain
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Champagne AA, Coverdale NS, Nashed JY, Fernandez-Ruiz J, Cook DJ. Resting CMRO 2 fluctuations show persistent network hyper-connectivity following exposure to sub-concussive collisions. NEUROIMAGE-CLINICAL 2019; 22:101753. [PMID: 30884366 PMCID: PMC6424143 DOI: 10.1016/j.nicl.2019.101753] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Revised: 02/20/2019] [Accepted: 03/09/2019] [Indexed: 12/20/2022]
Abstract
Exposure to head impacts may alter brain connectivity within cortical hubs such as the default-mode network (DMN). However, studies have yet to consider the confounding effects of altered resting cerebral blood flow (CBF0) and cerebrovascular reactivity (CVR) on changes in connectivity following sub-concussive impacts. Here, 23 Canadian collegiate football players were followed during a season using calibrated resting-state MRI and helmet accelerometers to examine the interplay between the neural and vascular factors that determine functional connectivity (FC). Connectivity-based analyses using blood oxygen level dependent (BOLD) and cerebral metabolic rate of oxygen consumption (CMRO2) mapping were used to study the DMN longitudinally. Network-specific decreases in CBF0 were observed one month following the season, while impaired CVR was documented at both mid-season and one month following the season, compared to pre-season baseline. Alterations in CBF0 and BOLD-based CVR throughout the season suggest that neurophysiological markers may show different susceptibility timelines following head impacts. DMN connectivity was increased throughout the season, independent of changes in cerebrovascular physiology, suggesting that alterations in FC following sub-concussive impacts are robust and independent of changes in brain hemodynamics. No significant correlations between impact kinematics and DMN connectivity changes were documented in this study. Altogether, these findings create a strong paradigm for future studies to examine the underlying neural and vascular mechanisms associated with increases in network connectivity following repeated exposure to sub-concussive collisions, in an effort to improve management of head impacts in contact sports. Changes in brain physiology do not confound BOLD-based changes in DMN connectivity. Physiological markers may show different susceptibility timelines to head impacts. CMRO2-based mapping shows robust evidence for sensitivity of DMN to head impacts.
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Affiliation(s)
- Allen A Champagne
- Centre for Neuroscience Studies, Room 260, Queen's University, Kingston, ON K7L 3N6, Canada.
| | - Nicole S Coverdale
- Centre for Neuroscience Studies, Room 260, Queen's University, Kingston, ON K7L 3N6, Canada.
| | - Joseph Y Nashed
- Centre for Neuroscience Studies, Room 260, Queen's University, Kingston, ON K7L 3N6, Canada.
| | - Juan Fernandez-Ruiz
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Av. Universidad 3000, Coyoacán, Ciudad de México 04510, México.
| | - Douglas J Cook
- Centre for Neuroscience Studies, Room 260, Queen's University, Kingston, ON K7L 3N6, Canada; Department of Surgery, Queen's University, Room 232, 18 Stuart St, Kingston, ON K7L 3N6, Canada.
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Juttukonda MR, Donahue MJ. Neuroimaging of vascular reserve in patients with cerebrovascular diseases. Neuroimage 2019; 187:192-208. [PMID: 29031532 PMCID: PMC5897191 DOI: 10.1016/j.neuroimage.2017.10.015] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 10/01/2017] [Accepted: 10/07/2017] [Indexed: 12/21/2022] Open
Abstract
Cerebrovascular reactivity, defined broadly as the ability of brain parenchyma to adjust cerebral blood flow in response to altered metabolic demand or a vasoactive stimulus, is being measured with increasing frequency and may have a use for portending new or recurrent stroke risk in patients with cerebrovascular disease. The purpose of this review is to outline (i) the physiological basis of variations in cerebrovascular reactivity, (ii) available approaches for measuring cerebrovascular reactivity in research and clinical settings, and (iii) clinically-relevant cerebrovascular reactivity findings in the context of patients with cerebrovascular disease, including atherosclerotic arterial steno-occlusion, non-atherosclerotic arterial steno-occlusion, anemia, and aging. Literature references summarizing safety considerations for these procedures and future directions for standardizing protocols and post-processing procedures across centers are presented in the specific context of major unmet needs in the setting of cerebrovascular disease.
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Affiliation(s)
- Meher R Juttukonda
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Manus J Donahue
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Psychiatry, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, USA.
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Ebner F, Ullén S, Åneman A, Cronberg T, Mattsson N, Friberg H, Hassager C, Kjærgaard J, Kuiper M, Pelosi P, Undén J, Wise MP, Wetterslev J, Nielsen N. Associations between partial pressure of oxygen and neurological outcome in out-of-hospital cardiac arrest patients: an explorative analysis of a randomized trial. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2019; 23:30. [PMID: 30691510 PMCID: PMC6348606 DOI: 10.1186/s13054-019-2322-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Accepted: 01/11/2019] [Indexed: 12/31/2022]
Abstract
Objective Exposure to hyperoxemia and hypoxemia is common in out-of-hospital cardiac arrest (OHCA) patients following return of spontaneous circulation (ROSC), but its effects on neurological outcome are uncertain, and study results are inconsistent. Methods Exploratory post hoc substudy of the Target Temperature Management (TTM) trial, including 939 patients after OHCA with return of spontaneous circulation (ROSC). The association between serial arterial partial pressures of oxygen (PaO2) during 37 h following ROSC and neurological outcome at 6 months, evaluated by Cerebral Performance Category (CPC), dichotomized to good (CPC 1–2) and poor (CPC 3–5), was investigated. In our analyses, we tested the association of hyperoxemia and hypoxemia, time-weighted mean PaO2, maximum PaO2 difference, and gradually increasing PaO2 levels (13.3–53.3 kPa) with poor neurological outcome. A subsequent analysis investigated the association between PaO2 and a biomarker of brain injury, peak serum Tau levels. Results Eight hundred sixty-nine patients were eligible for analysis. Three hundred patients (35%) were exposed to hyperoxemia or hypoxemia at some time point after ROSC. Our analyses did not reveal a significant association between hyperoxemia, hypoxemia, time-weighted mean PaO2 exposure or maximum PaO2 difference and poor neurological outcome at 6-month follow-up after correction for co-variates (all analyses p = 0.146–0.847). We were not able to define a PaO2 level significantly associated with the onset of poor neurological outcome. Peak serum Tau levels at either 48 or 72 h after ROSC were not associated with PaO2. Conclusion Hyperoxemia or hypoxemia exposure occurred in one third of the patients during the first 37 h of hospitalization and was not significantly associated with poor neurological outcome after 6 months or with the peak s-Tau levels at either 48 or 72 h after ROSC. Electronic supplementary material The online version of this article (10.1186/s13054-019-2322-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Florian Ebner
- Department of Clinical Sciences Lund, Anesthesia and Intensive Care, Lund University, Helsingborg Hospital, S-251 87, Helsingborg, Sweden.
| | - Susann Ullén
- Clinical Studies Sweden, Skane University Hospital, Remissgatan 4, S-221 85, Lund, Sweden
| | - Anders Åneman
- Department of Intensive Care, Liverpool Hospital, Locked Bag 7103, Liverpool BC, Sydney, NSW, 1871, Australia
| | - Tobias Cronberg
- Department of Clinical Sciences Lund, Neurology, Lund University, Skane University Hospital, Getingevägen 5, 221 85, Lund, Sweden
| | - Niklas Mattsson
- Department of Clinical Sciences Lund, Neurology, Lund University, Skane University Hospital, Getingevägen 5, 221 85, Lund, Sweden
| | - Hans Friberg
- Department of Clinical Sciences Lund, Anesthesia and Intensive Care, Lund University, Skane University Hospital, Getingevägen 5, 221 85, Lund, Sweden
| | - Christian Hassager
- Department of Cardiology, Rigshospitalet, University of Copenhagen, DK 2100, Copenhagen, Denmark.,Department of Clinical Medicine, University of Copenhagen, DK 2100, Copenhagen, Denmark
| | - Jesper Kjærgaard
- Department of Cardiology, Rigshospitalet, University of Copenhagen, DK 2100, Copenhagen, Denmark.,Department of Clinical Medicine, University of Copenhagen, DK 2100, Copenhagen, Denmark
| | - Michael Kuiper
- Intensive Care Unit, Leeuwarden Medical Centrum, Borniastraat 38, NL8934 AD, Leeuwarden, Netherlands
| | - Paolo Pelosi
- Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genoa, Italy.,Department of Anesthesia and Intensive Care, IRCCS San Martino Policlinico Hospital, Genoa, Italy
| | - Johan Undén
- Department of Clinical Sciences Lund, Anesthesia and Intensive Care, Lund University, Hallands Hospital, S-30233, Halmstad, Sweden
| | - Matt P Wise
- Adult Critical Care, University Hospital of Wales, Heath Park, Cardiff, CF144XW, UK
| | - Jørn Wetterslev
- Copenhagen Trial Unit, Centre for Clinical Intervention Research, Dpt. 7812, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, DK-2100, Copenhagen, Denmark
| | - Niklas Nielsen
- Department of Clinical Sciences Lund, Anesthesia and Intensive Care, Lund University, Helsingborg Hospital, S-251 87, Helsingborg, Sweden
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Liu EY, Haist F, Dubowitz DJ, Buxton RB. Cerebral blood volume changes during the BOLD post-stimulus undershoot measured with a combined normoxia/hyperoxia method. Neuroimage 2019; 185:154-163. [PMID: 30315908 PMCID: PMC6292691 DOI: 10.1016/j.neuroimage.2018.10.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 10/09/2018] [Accepted: 10/09/2018] [Indexed: 10/28/2022] Open
Abstract
Cerebral blood flow (CBF) and blood oxygenation level dependent (BOLD) signal measurements make it possible to estimate steady-state changes in the cerebral metabolic rate of oxygen (CMRO2) with a calibrated BOLD method. However, extending this approach to measure the dynamics of CMRO2 requires an additional assumption: that deoxygenated cerebral blood volume (CBVdHb) follows CBF in a predictable way. A test-case for this assumption is the BOLD post-stimulus undershoot, for which one proposed explanation is a strong uncoupling of flow and blood volume with an elevated level of CBVdHb during the post-stimulus period compared to baseline due to slow blood volume recovery (Balloon Model). A challenge in testing this model is that CBVdHb differs from total blood volume, which can be measured with other techniques. In this study, the basic hypothesis of elevated CBVdHb during the undershoot was tested, based on the idea that the BOLD signal change when a subject switches from breathing a normoxic gas to breathing a hyperoxic gas is proportional to the absolute CBVdHb. In 19 subjects (8F), dual-echo BOLD responses were measured in primary visual cortex during a flickering radial checkerboard stimulus in normoxia, and the identical experiment was repeated in hyperoxia (50% O2/balance N2). The BOLD signal differences between normoxia and hyperoxia for the pre-stimulus baseline, stimulus, and post-stimulus periods were compared using an equivalent BOLD signal calculated from measured R2* changes to eliminate signal drifts. Relative to the pre-stimulus baseline, the average BOLD signal change from normoxia to hyperoxia was negative during the undershoot period (p = 0.0251), consistent with a reduction of CBVdHb and contrary to the prediction of the Balloon Model. Based on these results, the BOLD post-stimulus undershoot does not represent a case of strong uncoupling of CBVdHb and CBF, supporting the extension of current calibrated BOLD methods to estimate the dynamics of CMRO2.
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Affiliation(s)
- Eulanca Y Liu
- Neurosciences Graduate Program, Medical Scientist Training Program, University of California, San Diego, USA; Center for Functional MRI, University of California, San Diego, USA
| | - Frank Haist
- Psychiatry, University of California, San Diego, USA; Center for Human Development, University of California, San Diego, USA
| | - David J Dubowitz
- Center for Functional MRI, University of California, San Diego, USA; Radiology, University of California, San Diego, USA
| | - Richard B Buxton
- Center for Functional MRI, University of California, San Diego, USA; Radiology, University of California, San Diego, USA.
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Mattishent K, Thavarajah M, Sinha A, Peel A, Egger M, Solomkin J, de Jonge S, Latif A, Berenholtz S, Allegranzi B, Loke YK. Safety of 80% vs 30-35% fraction of inspired oxygen in patients undergoing surgery: a systematic review and meta-analysis. Br J Anaesth 2019; 122:311-324. [PMID: 30770049 DOI: 10.1016/j.bja.2018.11.026] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 11/06/2018] [Accepted: 11/08/2018] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Evidence-based guidelines from the World Health Organization (WHO) have recommended a high (80%) fraction of inspired oxygen (FiO2) to reduce surgical site infection in adult surgical patients undergoing general anaesthesia with tracheal intubation. However, there is ongoing debate over the safety of high FiO2. We performed a systematic review to define the relative risk of clinically relevant adverse events (AE) associated with high FiO2. METHODS We reviewed potentially relevant articles from the WHO review supporting the recommendation, including an updated (July 2018) search of EMBASE and PubMed for randomised and non-randomised controlled studies reporting AE in surgical patients receiving 80% FiO2 compared with 30-35% FiO2. We assessed study quality and performed meta-analyses of risk ratios (RR) comparing 80% FiO2 against 30-35% for major complications, mortality, and intensive care admission. RESULTS We included 17 moderate-good quality trials and two non-randomised studies with serious-critical risk of bias. No evidence of harm with high FiO2 was found for major AE in the meta-analysis of randomised trials: atelectasis RR 0.91 [95% confidence interval (CI) 0.59-1.42); cardiovascular events RR 0.90 (95% CI 0.32-2.54); intensive care admission RR 0.93 (95% CI 0.7-1.12); and death during the trial RR 0.49 (95% CI 0.17-1.37). One non-randomised study reported that high FiO2 was associated with major respiratory AE [RR 1.99 (95% CI 1.72-2.31)]. CONCLUSIONS No definite signal of harm with 80% FiO2 in adult surgical patients undergoing general anaesthesia was demonstrated and there is little evidence on safety-related issues to discourage its use in this population.
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Affiliation(s)
| | | | - Ashnish Sinha
- Norwich Medical School, University of East Anglia, Norwich, UK
| | - Adam Peel
- Norwich Medical School, University of East Anglia, Norwich, UK
| | - Matthias Egger
- Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
| | - Joseph Solomkin
- Department of Surgery, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Stijn de Jonge
- Department of Surgery, Amsterdam Gastroenterology and Metabolism, Amsterdam Infection and Immunity, Amsterdam UMC, Location AMC, University of Amsterdam, the Netherlands
| | - Asad Latif
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Armstrong Institute for Patient Safety and Quality, Johns Hopkins Medicine, Baltimore, MD, USA
| | - Sean Berenholtz
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Armstrong Institute for Patient Safety and Quality, Johns Hopkins Medicine, Baltimore, MD, USA
| | - Benedetta Allegranzi
- Infection Prevention and Control Global Unit, Service Delivery and Safety, World Health Organization, Geneva, Switzerland.
| | - Yoon Kong Loke
- Norwich Medical School, University of East Anglia, Norwich, UK
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MacDonald ME, Berman AJ, Mazerolle EL, Williams RJ, Pike GB. Modeling hyperoxia-induced BOLD signal dynamics to estimate cerebral blood flow, volume and mean transit time. Neuroimage 2018; 178:461-474. [DOI: 10.1016/j.neuroimage.2018.05.066] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 05/25/2018] [Accepted: 05/27/2018] [Indexed: 11/30/2022] Open
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Lång M, Skrifvars MB, Siironen J, Tanskanen P, Ala-Peijari M, Koivisto T, Djafarzadeh S, Bendel S. A pilot study of hyperoxemia on neurological injury, inflammation and oxidative stress. Acta Anaesthesiol Scand 2018; 62:801-810. [PMID: 29464691 DOI: 10.1111/aas.13093] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 01/11/2018] [Accepted: 01/19/2018] [Indexed: 12/25/2022]
Abstract
BACKGROUND Normobaric hyperoxia is used to alleviate secondary brain ischaemia in patients with traumatic brain injury (TBI), but clinical evidence is limited and hyperoxia may cause adverse events. METHODS An open label, randomised controlled pilot study comparing blood concentrations of reactive oxygen species (ROS), interleukin 6 (IL-6) and neuron-specific enolase (NSE) between two different fractions of inspired oxygen in severe TBI patients on mechanical ventilation. RESULTS We enrolled 27 patients in the Fi O2 0.40 group and 38 in the Fi O2 0.70 group; 19 and 23 patients, respectively, completed biochemical analyses. In baseline, there were no differences between Fi O2 0.40 and Fi O2 0.70 groups, respectively, in ROS (64.8 nM [22.6-102.1] vs. 64.9 nM [26.8-96.3], P = 0.80), IL-6 (group 92.4 pg/ml [52.9-171.6] vs. 94.3 pg/ml [54.8-133.1], P = 0.52) or NSE (21.04 ug/l [14.0-30.7] vs. 17.8 ug/l [14.1-23.9], P = 0.35). ROS levels did not differ at Day 1 (24.2 nM [20.6-33.5] vs. 29.2 nM [22.7-69.2], P = 0.10) or at Day 2 (25.4 nM [21.7-37.4] vs. 47.3 nM [34.4-126.1], P = 0.95). IL-6 concentrations did not differ at Day 1 (112.7 pg/ml [65.9-168.9) vs. 83.9 pg/ml [51.8-144.3], P = 0.41) or at Day 3 (55.0 pg/ml [34.2-115.6] vs. 49.3 pg/ml [34.4-126.1], P = 0.95). NSE levels did not differ at Day 1 (15.9 ug/l [9.0-24.3] vs. 15.3 ug/l [12.2-26.3], P = 0.62). There were no differences between groups in the incidence of pulmonary complications. CONCLUSION Higher fraction of inspired oxygen did not increase blood concentrations of markers of oxidative stress, inflammation or neurological injury or the incidence of pulmonary complications in severe TBI patients on mechanical ventilation.
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Affiliation(s)
- M. Lång
- Department of Intensive Care Medicine; Kuopio University Hospital; Kys Finland
| | - M. B. Skrifvars
- Department of Anaesthesiology, Intensive Care and Pain Medicine; Helsinki University and Helsinki University Hospital; Helsinki Finland
| | - J. Siironen
- Department of Neurosurgery; Helsinki University and Helsinki University Hospital; Helsinki Finland
| | - P. Tanskanen
- Department of Anaesthesiology, Intensive Care and Pain Medicine; Helsinki University and Helsinki University Hospital; Helsinki Finland
| | - M. Ala-Peijari
- Department of Intensive Care Medicine; Tampere University Hospital; Tampere Finland
| | - T. Koivisto
- Department of Neurosurgery; Kuopio University Hospital; Kys Finland
| | - S. Djafarzadeh
- Department of Intensive Care Medicine, Inselspital; Bern University Hospital; Bern Switzerland
| | - S. Bendel
- Department of Intensive Care Medicine; Kuopio University Hospital; Kys Finland
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Duffin J, Sobczyk O, McKetton L, Crawley A, Poublanc J, Venkatraghavan L, Sam K, Mutch WA, Mikulis D, Fisher JA. Cerebrovascular Resistance: The Basis of Cerebrovascular Reactivity. Front Neurosci 2018; 12:409. [PMID: 29973862 PMCID: PMC6020782 DOI: 10.3389/fnins.2018.00409] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 05/28/2018] [Indexed: 12/20/2022] Open
Abstract
The cerebral vascular network regulates blood flow distribution by adjusting vessel diameters, and consequently resistance to flow, in response to metabolic demands (neurovascular coupling) and changes in perfusion pressure (autoregulation). Deliberate changes in carbon dioxide (CO2) partial pressure may be used to challenge this regulation and assess its performance since CO2 also acts to change vessel diameter. Cerebrovascular reactivity (CVR), the ratio of cerebral blood flow (CBF) response to CO2 stimulus is currently used as a performance metric. However, the ability of CVR to reflect the responsiveness of a particular vascular region is confounded by that region’s inclusion in the cerebral vascular network, where all regions respond to the global CO2 stimulus. Consequently, local CBF responses reflect not only changes in the local vascular resistance but also the effect of changes in local perfusion pressure resulting from redistribution of flow within the network. As a result, the CBF responses to CO2 take on various non-linear patterns that are not well-described by straight lines. We propose a method using a simple model to convert these CBF response patterns to the pattern of resistance responses that underlie them. The model, which has been used previously to explain the steal phenomenon, consists of two vascular branches in parallel fed by a major artery with a fixed resistance unchanging with CO2. One branch has a reference resistance with a sigmoidal response to CO2, representative of a voxel with a robust response. The other branch has a CBF equal to the measured CBF response to CO2 of any voxel under examination. Using the model to calculate resistance response patterns of the examined branch showed sigmoidal patterns of resistance response, regardless of the measured CBF response patterns. The sigmoid parameters of the resistance response pattern of examined voxels may be mapped to their anatomical location. We show an example for a healthy subject and for a patient with steno-occlusive disease to illustrate. We suggest that these maps provide physiological insight into the regulation of CBF distribution.
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Affiliation(s)
- James Duffin
- Department of Physiology, University of Toronto, Toronto, ON, Canada.,Department of Anaesthesia and Pain Management, University Health Network, University of Toronto, Toronto, ON, Canada
| | - Olivia Sobczyk
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Larissa McKetton
- Joint Department of Medical Imaging and the Functional Neuroimaging Lab, University Health Network, Toronto, ON, Canada
| | - Adrian Crawley
- Joint Department of Medical Imaging and the Functional Neuroimaging Lab, University Health Network, Toronto, ON, Canada
| | - Julien Poublanc
- Joint Department of Medical Imaging and the Functional Neuroimaging Lab, University Health Network, Toronto, ON, Canada
| | - Lashmi Venkatraghavan
- Department of Anaesthesia and Pain Management, University Health Network, University of Toronto, Toronto, ON, Canada
| | - Kevin Sam
- Joint Department of Medical Imaging and the Functional Neuroimaging Lab, University Health Network, Toronto, ON, Canada
| | - W Alan Mutch
- Department of Anesthesia and Perioperative Medicine, University of Manitoba, Winnipeg, MB, Canada
| | - David Mikulis
- Department of Physiology, University of Toronto, Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Toronto, ON, Canada.,Joint Department of Medical Imaging and the Functional Neuroimaging Lab, University Health Network, Toronto, ON, Canada
| | - Joseph A Fisher
- Department of Physiology, University of Toronto, Toronto, ON, Canada.,Department of Anaesthesia and Pain Management, University Health Network, University of Toronto, Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Toronto, ON, Canada
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De Vis JB, Lu H, Ravi H, Hendrikse J, Liu P. Spatial distribution of flow and oxygenation in the cerebral venous drainage system. J Magn Reson Imaging 2018; 47:1091-1098. [PMID: 28791759 PMCID: PMC5807233 DOI: 10.1002/jmri.25833] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 07/25/2017] [Indexed: 12/16/2022] Open
Abstract
PURPOSE To investigate the venous oxygenation and flow in the brain, and determine how they might change under challenged states. MATERIALS AND METHODS Eight healthy human subjects (24-37 years) were studied. T2 -relaxation under spin tagging (TRUST) magnetic resonance imaging (MRI) and phase-contrast MRI were performed to measure venous oxygenation and venous blood flow, respectively, in the superior sagittal sinus (SSS), the straight sinus (SS), and the internal jugular veins (IJVs). Venous oxygenation was assessed at room air (0.03%CO2 , 21%O2 ) and under hyperoxia (O%CO2 , 95%O2 , and 5%N2 ) conditions. Venous blood flow was assessed at room air and under hypercapnia (5%CO2 , 21%O2 , and 74%N2 ) conditions. Whole-brain blood flow was also measured at the four feeding arteries of the brain using phase-contrast MRI. The changes in venous oxygenation and blood flow from room air to hyperoxia or hypercapnia conditions were tested using paired t-tests. RESULTS Venous oxygenation in the SSS, the SS, and the IJVs was 61 ± 4%, 64 ± 4%, and 62 ± 4%, respectively, at room air, and increased to 70 ± 3% (P < 0.01 compared to room air), 71 ± 5% (P = 0.59), and 68 ± 5% (P < 0.05) under hyperoxic condition. The SSS, SS, and IJV drained 46 ± 9%, 16 ± 4%, and 79 ± 1% of whole-brain blood flow, respectively, and this flow distribution did not change under hypercapnic condition (P > 0.5). CONCLUSION The results found in this study provide insight into the venous oxygenation and venous flow distribution and its heterogeneity among different venous structures. LEVEL OF EVIDENCE 1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:1091-1098.
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Affiliation(s)
- Jill B. De Vis
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Hanzhang Lu
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Harshan Ravi
- Center for Neuroscience and Regenerative Medicine, National Institutes of Health, Bethesda, MD
| | - Jeroen Hendrikse
- Department of Radiology, University Medical Center Utrecht, The Netherlands
| | - Peiying Liu
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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43
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Berman AJ, Mazerolle EL, MacDonald ME, Blockley NP, Luh WM, Pike GB. Gas-free calibrated fMRI with a correction for vessel-size sensitivity. Neuroimage 2018; 169:176-188. [DOI: 10.1016/j.neuroimage.2017.12.047] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 12/11/2017] [Accepted: 12/14/2017] [Indexed: 10/18/2022] Open
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Brugniaux JV, Coombs GB, Barak OF, Dujic Z, Sekhon MS, Ainslie PN. Highs and lows of hyperoxia: physiological, performance, and clinical aspects. Am J Physiol Regul Integr Comp Physiol 2018; 315:R1-R27. [PMID: 29488785 DOI: 10.1152/ajpregu.00165.2017] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Molecular oxygen (O2) is a vital element in human survival and plays a major role in a diverse range of biological and physiological processes. Although normobaric hyperoxia can increase arterial oxygen content ([Formula: see text]), it also causes vasoconstriction and hence reduces O2 delivery in various vascular beds, including the heart, skeletal muscle, and brain. Thus, a seemingly paradoxical situation exists in which the administration of oxygen may place tissues at increased risk of hypoxic stress. Nevertheless, with various degrees of effectiveness, and not without consequences, supplemental oxygen is used clinically in an attempt to correct tissue hypoxia (e.g., brain ischemia, traumatic brain injury, carbon monoxide poisoning, etc.) and chronic hypoxemia (e.g., severe COPD, etc.) and to help with wound healing, necrosis, or reperfusion injuries (e.g., compromised grafts). Hyperoxia has also been used liberally by athletes in a belief that it offers performance-enhancing benefits; such benefits also extend to hypoxemic patients both at rest and during rehabilitation. This review aims to provide a comprehensive overview of the effects of hyperoxia in humans from the "bench to bedside." The first section will focus on the basic physiological principles of partial pressure of arterial O2, [Formula: see text], and barometric pressure and how these changes lead to variation in regional O2 delivery. This review provides an overview of the evidence for and against the use of hyperoxia as an aid to enhance physical performance. The final section addresses pathophysiological concepts, clinical studies, and implications for therapy. The potential of O2 toxicity and future research directions are also considered.
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Affiliation(s)
| | - Geoff B Coombs
- Centre for Heart, Lung, and Vascular Health, University of British Columbia , Kelowna, British Columbia , Canada
| | - Otto F Barak
- Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia.,Faculty of Sport and Physical Education, University of Novi Sad, Novi Sad, Serbia
| | - Zeljko Dujic
- Department of Integrative Physiology, School of Medicine, University of Split , Split , Croatia
| | - Mypinder S Sekhon
- Centre for Heart, Lung, and Vascular Health, University of British Columbia , Kelowna, British Columbia , Canada.,Division of Critical Care Medicine, Department of Medicine, Vancouver General Hospital, University of British Columbia , Vancouver, British Columbia , Canada
| | - Philip N Ainslie
- Centre for Heart, Lung, and Vascular Health, University of British Columbia , Kelowna, British Columbia , Canada
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45
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Hua J, Liu P, Kim T, Donahue M, Rane S, Chen JJ, Qin Q, Kim SG. MRI techniques to measure arterial and venous cerebral blood volume. Neuroimage 2018; 187:17-31. [PMID: 29458187 DOI: 10.1016/j.neuroimage.2018.02.027] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 02/12/2018] [Accepted: 02/14/2018] [Indexed: 12/14/2022] Open
Abstract
The measurement of cerebral blood volume (CBV) has been the topic of numerous neuroimaging studies. To date, however, most in vivo imaging approaches can only measure CBV summed over all types of blood vessels, including arterial, capillary and venous vessels in the microvasculature (i.e. total CBV or CBVtot). As different types of blood vessels have intrinsically different anatomy, function and physiology, the ability to quantify CBV in different segments of the microvascular tree may furnish information that is not obtainable from CBVtot, and may provide a more sensitive and specific measure for the underlying physiology. This review attempts to summarize major efforts in the development of MRI techniques to measure arterial (CBVa) and venous CBV (CBVv) separately. Advantages and disadvantages of each type of method are discussed. Applications of some of the methods in the investigation of flow-volume coupling in healthy brains, and in the detection of pathophysiological abnormalities in brain diseases such as arterial steno-occlusive disease, brain tumors, schizophrenia, Huntington's disease, Alzheimer's disease, and hypertension are demonstrated. We believe that the continual development of MRI approaches for the measurement of compartment-specific CBV will likely provide essential imaging tools for the advancement and refinement of our knowledge on the exquisite details of the microvasculature in healthy and diseased brains.
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Affiliation(s)
- Jun Hua
- Neurosection, Div. of MRI Research, Dept. of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA.
| | - Peiying Liu
- Neurosection, Div. of MRI Research, Dept. of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Tae Kim
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Manus Donahue
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Swati Rane
- Radiology, University of Washington Medical Center, Seattle, WA, USA
| | - J Jean Chen
- Rotman Research Institute, Baycrest Centre, Canada; Department of Medical Biophysics, University of Toronto, Canada
| | - Qin Qin
- Neurosection, Div. of MRI Research, Dept. of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Seong-Gi Kim
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, South Korea; Department of Biomedical Engineering, Sungkyunkwan University, Suwon, South Korea
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46
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Zun Z, Limperopoulos C. Placental perfusion imaging using velocity-selective arterial spin labeling. Magn Reson Med 2018; 80:1036-1047. [PMID: 29436733 DOI: 10.1002/mrm.27100] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 12/30/2017] [Accepted: 01/02/2018] [Indexed: 11/10/2022]
Affiliation(s)
- Zungho Zun
- Division of Diagnostic Imaging and Radiology, Children's National Medical Center, Washington, DC.,Division of Fetal and Transitional Medicine, Children's National Medical Center, Washington, DC.,Department of Pediatrics, School of Medicine and Health Sciences, George Washington University, Washington, DC.,Department of Radiology, School of Medicine and Health Sciences, George Washington University, Washington, DC
| | - Catherine Limperopoulos
- Division of Diagnostic Imaging and Radiology, Children's National Medical Center, Washington, DC.,Division of Fetal and Transitional Medicine, Children's National Medical Center, Washington, DC.,Department of Pediatrics, School of Medicine and Health Sciences, George Washington University, Washington, DC.,Department of Radiology, School of Medicine and Health Sciences, George Washington University, Washington, DC
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47
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Bright MG, Croal PL, Blockley NP, Bulte DP. Multiparametric measurement of cerebral physiology using calibrated fMRI. Neuroimage 2017; 187:128-144. [PMID: 29277404 DOI: 10.1016/j.neuroimage.2017.12.049] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 12/14/2017] [Accepted: 12/15/2017] [Indexed: 02/07/2023] Open
Abstract
The ultimate goal of calibrated fMRI is the quantitative imaging of oxygen metabolism (CMRO2), and this has been the focus of numerous methods and approaches. However, one underappreciated aspect of this quest is that in the drive to measure CMRO2, many other physiological parameters of interest are often acquired along the way. This can significantly increase the value of the dataset, providing greater information that is clinically relevant, or detail that can disambiguate the cause of signal variations. This can also be somewhat of a double-edged sword: calibrated fMRI experiments combine multiple parameters into a physiological model that requires multiple steps, thereby providing more opportunity for error propagation and increasing the noise and error of the final derived values. As with all measurements, there is a trade-off between imaging time, spatial resolution, coverage, and accuracy. In this review, we provide a brief overview of the benefits and pitfalls of extracting multiparametric measurements of cerebral physiology through calibrated fMRI experiments.
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Affiliation(s)
- Molly G Bright
- Sir Peter Mansfield Imaging Centre, School of Medicine, University of Nottingham, Nottingham, UK; Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Paula L Croal
- IBME, Department of Engineering Science, University of Oxford, Oxford, UK
| | - Nicholas P Blockley
- FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Daniel P Bulte
- IBME, Department of Engineering Science, University of Oxford, Oxford, UK; FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
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48
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A novel perspective to calibrate temporal delays in cerebrovascular reactivity using hypercapnic and hyperoxic respiratory challenges. Neuroimage 2017; 187:154-165. [PMID: 29217405 DOI: 10.1016/j.neuroimage.2017.11.044] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 11/19/2017] [Accepted: 11/20/2017] [Indexed: 01/21/2023] Open
Abstract
Redistribution of blood flow across different brain regions, arising from the vasoactive nature of hypercapnia, can introduce errors when examining cerebrovascular reactivity (CVR) response delays. In this study, we propose a novel analysis method to characterize hemodynamic delays in the blood oxygen level dependent (BOLD) response to hypercapnia, and hyperoxia, as a way to provide insight into transient differences in vascular reactivity between cortical regions, and across tissue depths. A pseudo-continuous arterial spin labeling sequence was used to acquire BOLD and cerebral blood flow simultaneously in 19 healthy adults (12 F; 20 ± 2 years) during boxcar CO2 and O2 gas inhalation paradigms. Despite showing distinct differences in hypercapnia-induced response delay times (P < 0.05; Bonferroni corrected), grey matter regions showed homogenous hemodynamic latencies (P > 0.05) once calibrated for bolus arrival time derived using non-vasoactive hyperoxic gas challenges. Longer hypercapnic temporal delays were observed as the depth of the white matter tissue increased, although no significant differences in response lag were found during hyperoxia across tissue depth, or between grey and white matter. Furthermore, calibration of hypercapnic delays using hyperoxia revealed that deeper white matter layers may be more prone to dynamic redistribution of blood flow, which introduces response lag times ranging between 1 and 3 s in healthy subjects. These findings suggest that the combination of hypercapnic and hyperoxic gas-inhalation MRI can be used to distinguish between differences in CVR that arise as a result of delayed stimulus arrival time (due to the local architecture of the cerebrovasculature), or preferential blood flow distribution. Calibrated response delays to hypercapnia provide important insights into cerebrovascular physiology, and may be used to correct response delays associated with vascular impairment.
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49
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Should Hyperoxia Be Avoided During Sepsis? An Experimental Study in Ovine Peritonitis*. Crit Care Med 2017; 45:e1060-e1067. [DOI: 10.1097/ccm.0000000000002524] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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50
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Duffin J, Sobczyk O, Crawley A, Poublanc J, Venkatraghavan L, Sam K, Mutch A, Mikulis D, Fisher J. The role of vascular resistance in BOLD responses to progressive hypercapnia. Hum Brain Mapp 2017; 38:5590-5602. [PMID: 28782872 DOI: 10.1002/hbm.23751] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 07/20/2017] [Accepted: 07/20/2017] [Indexed: 12/22/2022] Open
Abstract
The ability of the cerebral vasculature to regulate vascular diameter, hence resistance and cerebral blood flow (CBF), in response to metabolic demands (neurovascular coupling), and perfusion pressure changes (autoregulation) may be assessed by measuring the CBF response to carbon dioxide (CO2 ). In healthy individuals, the CBF response to a ramp CO2 stimulus from hypocapnia to hypercapnia is assumed sigmoidal or linear. However, other response patterns commonly occur, especially in individuals with cerebrovascular disease, and these remain unexplained. CBF responses to CO2 in a vascular region are determined by the combined effects of the innate vascular responses to CO2 and the local perfusion pressure; the latter ensuing from pressure-flow interactions within the cerebral vascular network. We modeled this situation as two vascular beds perfused in parallel from a fixed resistance source. Our premise is that all vascular beds have a sigmoidal reduction of resistance in response to a progressive rise in CO2 . Surrogate CBF data to test the model was provided by magnetic resonance imaging of blood oxygen level-dependent (BOLD) signals. The model successfully generated all the various BOLD-CO2 response patterns, providing a physiological explanation of CBF distribution as relative differences in the network of vascular bed resistance responses to CO2 . Hum Brain Mapp 38:5590-5602, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- James Duffin
- Department of Physiology, University Health Network, Toronto, Canada.,Department of Anaesthesia and Pain Management, University Health Network, University of Toronto, Toronto, Canada
| | - Olivia Sobczyk
- Institute of Medical Science, University of Toronto, Toronto, Canada
| | - Adrian Crawley
- Joint Department of Medical Imaging and the Functional Neuroimaging Lab, University Health Network, Toronto, Canada
| | - Julien Poublanc
- Joint Department of Medical Imaging and the Functional Neuroimaging Lab, University Health Network, Toronto, Canada
| | - Lashmi Venkatraghavan
- Department of Anaesthesia and Pain Management, University Health Network, University of Toronto, Toronto, Canada
| | - Kevin Sam
- Joint Department of Medical Imaging and the Functional Neuroimaging Lab, University Health Network, Toronto, Canada
| | - Alan Mutch
- Department of Anesthesia and Perioperative Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - David Mikulis
- Institute of Medical Science, University of Toronto, Toronto, Canada.,Joint Department of Medical Imaging and the Functional Neuroimaging Lab, University Health Network, Toronto, Canada
| | - Joseph Fisher
- Department of Physiology, University Health Network, Toronto, Canada.,Department of Anaesthesia and Pain Management, University Health Network, University of Toronto, Toronto, Canada.,Institute of Medical Science, University of Toronto, Toronto, Canada
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