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Engstrom AC, Alitin JP, Kapoor A, Dutt S, Lohman T, Sible IJ, Marshall AJ, Shenasa F, Gaubert A, Ferrer F, Nguyen A, Bradford DR, Rodgers K, Sordo L, Head E, Shao X, Wang DJ, Nation DA. Spontaneous cerebrovascular reactivity at rest in older adults with and without mild cognitive impairment and memory deficits. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.06.18.24309109. [PMID: 38946941 PMCID: PMC11213117 DOI: 10.1101/2024.06.18.24309109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Background Older adults with mild cognitive impairment (MCI) exhibit deficits in cerebrovascular reactivity (CVR), suggesting CVR is a biomarker for vascular contributions to MCI. This study examined if spontaneous CVR is associated with MCI and memory impairment. Methods 161 older adults free of dementia or major neurological/psychiatric disorders were recruited. Participants underwent clinical interviews, cognitive testing, venipuncture for Alzheimer's biomarkers, and brain MRI. Spontaneous CVR was quantified during 5 minutes of rest. Results Whole brain CVR was negatively associated with age, but not MCI. Lower CVR in the parahippocampal gyrus (PHG) was found in participants with MCI and was linked to worse memory performance on memory tests. Results remained significant after adjusting for Alzheimer's biomarkers and vascular risk factors. Conclusion Spontaneous CVR deficits in the PHG are observed in older adults with MCI and memory impairment, indicating medial temporal microvascular dysfunction's role in cognitive decline.
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Affiliation(s)
- Allison C Engstrom
- Department of Psychological Science, University of California, Irvine, Irvine, CA, USA
| | - John Paul Alitin
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Arunima Kapoor
- Department of Psychological Science, University of California, Irvine, Irvine, CA, USA
| | - Shubir Dutt
- Memory and Aging Center, Weill Institute for Neurosciences, Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | - Trevor Lohman
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Isabel J Sible
- Department of Psychology, University of Southern California, Los Angeles, CA, USA
| | - Anisa J Marshall
- Department of Psychology, University of Southern California, Los Angeles, CA, USA
| | - Fatemah Shenasa
- Department of Psychological Science, University of California, Irvine, Irvine, CA, USA
| | - Aimée Gaubert
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Farrah Ferrer
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - Amy Nguyen
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
| | - David Robert Bradford
- Center for Innovations in Brain Science, Department of Pharmacology, University of Arizona, Tucson, AZ, USA
| | - Kathleen Rodgers
- Center for Innovations in Brain Science, Department of Pharmacology, University of Arizona, Tucson, AZ, USA
| | - Lorena Sordo
- Department of Pathology and Laboratory Medicine, University of California, Irvine, Irvine, CA, USA
| | - Elizabeth Head
- Department of Pathology and Laboratory Medicine, University of California, Irvine, Irvine, CA, USA
| | - Xingfeng Shao
- Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, CA, USA
| | - Danny Jj Wang
- Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, CA, USA
| | - Daniel A Nation
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, USA
- Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
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Sirant LW, Singh J, Martin S, Gaul CA, Stuart-Hill L, Candow DG, Mang C, Patrick Neary J. Long-term effects of multiple concussions on prefrontal cortex oxygenation during a hypercapnic challenge in retired contact sport athletes. Brain Res 2024; 1826:148735. [PMID: 38110074 DOI: 10.1016/j.brainres.2023.148735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 12/14/2023] [Accepted: 12/15/2023] [Indexed: 12/20/2023]
Abstract
This exploratory study aimed to investigate the long-term effects of multiple concussions on prefrontal cortex oxygenation during a five-minute hypercapnic challenge using Near Infrared Spectroscopy (NIRS). 55 physically active retired contact sport male athletes with three or more previous concussions (mTBI) were recruited along with 29 physically active males with no concussions history (CTRL). Participants completed five minutes of seated rest prior to the five-minute hypercapnic challenge (20-second breath-hold, 40-second recovery breathing; five times). NIRS measured right and left side oxygenated (O2Hb), deoxygenated (HHb), total (tHb) haemoglobin, and haemoglobin difference (HbDiff) with all parameters analysed through changes in average maximal and minimal values (ΔMAX), Z-scores, and standard deviations. Right prefrontal cortex HbDiff ΔMAX was significantly higher in the mTBI compared to CTRL (p = 0.045) group. Left prefrontal cortex O2Hb ΔMAX (p = 0.040), HHb Z-Scores (p = 0.008), and HbDiff ΔMAX(p = 0.014) were significantly higher in the mTBI group. Within-group right vs left analyses demonstrated significantly lower left HbDiff ΔMAX (p = 0.048) and HbDiff Z-scores (p = 0.002) in the mTBI group, while the CTRL group had significantly lower left HHb Z-scores (p = 0.003) and left tHb Z-scores (p = 0.042). This study provides preliminary evidence that athletes with a history of three or more concussions may have impaired prefrontal cortex oxygenation parameters during a hypercapnic challenge.
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Affiliation(s)
- Luke W Sirant
- University of Regina, Faculty of Kinesiology and Health Studies, Regina, SK, Canada
| | - Jyotpal Singh
- University of Regina, Faculty of Kinesiology and Health Studies, Regina, SK, Canada
| | - Steve Martin
- University of Victoria, School of Exercise Science, Physical and Health Education, Victoria, BC, Canada
| | - Catherine A Gaul
- University of Victoria, School of Exercise Science, Physical and Health Education, Victoria, BC, Canada
| | - Lynneth Stuart-Hill
- University of Victoria, School of Exercise Science, Physical and Health Education, Victoria, BC, Canada
| | - Darren G Candow
- University of Regina, Faculty of Kinesiology and Health Studies, Regina, SK, Canada
| | - Cameron Mang
- University of Regina, Faculty of Kinesiology and Health Studies, Regina, SK, Canada
| | - J Patrick Neary
- University of Regina, Faculty of Kinesiology and Health Studies, Regina, SK, Canada.
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3
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Fanning JP, Campbell BCV, Bulbulia R, Gottesman RF, Ko SB, Floyd TF, Messé SR. Perioperative stroke. Nat Rev Dis Primers 2024; 10:3. [PMID: 38238382 DOI: 10.1038/s41572-023-00487-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/01/2023] [Indexed: 01/23/2024]
Abstract
Ischaemic or haemorrhagic perioperative stroke (that is, stroke occurring during or within 30 days following surgery) can be a devastating complication following surgery. Incidence is reported in the 0.1-0.7% range in adults undergoing non-cardiac and non-neurological surgery, in the 1-5% range in patients undergoing cardiac surgery and in the 1-10% range following neurological surgery. However, higher rates have been reported when patients are actively assessed and in high-risk populations. Prognosis is significantly worse than stroke occurring in the community, with double the 30-day mortality, greater disability and diminished quality of life among survivors. Considering the annual volume of surgeries performed worldwide, perioperative stroke represents a substantial burden. Despite notable differences in aetiology, patient populations and clinical settings, existing clinical recommendations for perioperative stroke are extrapolated mainly from stroke in the community. Perioperative in-hospital stroke is unique with respect to the stroke occurring in other settings, and it is essential to apply evidence from other settings with caution and to identify existing knowledge gaps in order to effectively guide patient care and future research.
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Affiliation(s)
- Jonathon P Fanning
- Critical Care Research Group, The Prince Charles Hospital, Brisbane, Queensland, Australia.
- Anaesthesia & Perfusion Services, The Prince Charles Hospital, Brisbane, Queensland, Australia.
- Faculty of Medicine, University of Queensland, Brisbane, Queensland, Australia.
- The George Institute for Global Health, Sydney, New South Wales, Australia.
- Nuffield Department of Population Health, University of Oxford, Oxford, UK.
| | - Bruce C V Campbell
- Department of Neurology, Royal Melbourne Hospital, Parkville, Victoria, Australia
- Department of Medicine, University of Melbourne, Parkville, Victoria, Australia
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Richard Bulbulia
- Nuffield Department of Population Health, University of Oxford, Oxford, UK
- Department of Vascular Surgery, Gloucestershire Hospitals NHS Foundation Trust, Gloucester, UK
| | | | - Sang-Bae Ko
- Department of Neurology and Department of Critical Care Medicine, Seoul National University Hospital, Seoul, Korea
| | - Thomas F Floyd
- Department of Anaesthesiology & Pain Management, Department of Cardiovascular and Thoracic Surgery, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Steven R Messé
- Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA, USA
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Kopczak A, Stringer MS, van den Brink H, Kerkhofs D, Blair GW, van Dinther M, Reyes CA, Garcia DJ, Onkenhout L, Wartolowska KA, Thrippleton MJ, Kampaite A, Duering M, Staals J, Lesnik-Oberstein S, Muir KW, Middeke M, Norrving B, Bousser MG, Mansmann U, Rothwell PM, Doubal FN, van Oostenbrugge R, Biessels GJ, Webb AJS, Wardlaw JM, Dichgans M. Effect of blood pressure-lowering agents on microvascular function in people with small vessel diseases (TREAT-SVDs): a multicentre, open-label, randomised, crossover trial. Lancet Neurol 2023; 22:991-1004. [PMID: 37863608 DOI: 10.1016/s1474-4422(23)00293-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 06/15/2023] [Accepted: 08/01/2023] [Indexed: 10/22/2023]
Abstract
BACKGROUND Hypertension is the leading risk factor for cerebral small vessel disease. We aimed to determine whether antihypertensive drug classes differentially affect microvascular function in people with small vessel disease. METHODS We did a multicentre, open-label, randomised crossover trial with blinded endpoint assessment at five specialist centres in Europe. We included participants aged 18 years or older with symptomatic sporadic small vessel disease or cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and an indication for antihypertensive treatment. Participants were randomly assigned (1:1:1) to one of three sequences of antihypertensive treatment using a computer-generated multiblock randomisation, stratified by study site and patient group. A 2-week washout period was followed by three 4-week periods of oral monotherapy with amlodipine, losartan, or atenolol at approved doses. The primary endpoint was change in cerebrovascular reactivity (CVR) determined by blood oxygen level-dependent MRI response to hypercapnic challenge in normal-appearing white matter from the end of washout to the end of each treatment period. Efficacy analyses were done by intention-to-treat principles in all randomly assigned participants who had at least one valid assessment for the primary endpoint, and analyses were done separately for participants with sporadic small vessel disease and CADASIL. This trial is registered at ClinicalTrials.gov, NCT03082014, and EudraCT, 2016-002920-10, and is terminated. FINDINGS Between Feb 22, 2018, and April 28, 2022, 75 participants with sporadic small vessel disease (mean age 64·9 years [SD 9·9]) and 26 with CADASIL (53·1 years [7·0]) were enrolled and randomly assigned to treatment. 79 participants (62 with sporadic small vessel disease and 17 with CADASIL) entered the primary efficacy analysis. Change in CVR did not differ between study drugs in participants with sporadic small vessel disease (mean change in CVR 1·8 × 10-4%/mm Hg [SE 20·1; 95% CI -37·6 to 41·2] for amlodipine; 16·7 × 10-4%/mm Hg [20·0; -22·3 to 55·8] for losartan; -7·1 × 10-4%/mm Hg [19·6; -45·5 to 31·1] for atenolol; poverall=0·39) but did differ in patients with CADASIL (15·7 × 10-4%/mm Hg [SE 27·5; 95% CI -38·3 to 69·7] for amlodipine; 19·4 × 10-4%/mm Hg [27·9; -35·3 to 74·2] for losartan; -23·9 × 10-4%/mm Hg [27·5; -77·7 to 30·0] for atenolol; poverall=0·019). In patients with CADASIL, pairwise comparisons showed that CVR improved with amlodipine compared with atenolol (-39·6 × 10-4%/mm Hg [95% CI -72·5 to -6·6; p=0·019) and with losartan compared with atenolol (-43·3 × 10-4%/mm Hg [-74·3 to -12·3]; p=0·0061). No deaths occurred. Two serious adverse events were recorded, one while taking amlodipine (diarrhoea with dehydration) and one while taking atenolol (fall with fracture), neither of which was related to study drug intake. INTERPRETATION 4 weeks of treatment with amlodipine, losartan, or atenolol did not differ in their effects on cerebrovascular reactivity in people with sporadic small vessel disease but did result in differential treatment effects in patients with CADASIL. Whether antihypertensive drug classes differentially affect clinical outcomes in people with small vessel diseases requires further research. FUNDING EU Horizon 2020 programme.
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Affiliation(s)
- Anna Kopczak
- Institute for Stroke and Dementia Research, University Hospital, LMU Munich, Munich, Germany
| | - Michael S Stringer
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK; UK Dementia Research Institute, University of Edinburgh, Edinburgh, UK
| | - Hilde van den Brink
- Department of Neurology, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht, Netherlands
| | - Danielle Kerkhofs
- Department of Neurology and School for Cardiovascular Diseases, Maastricht University Medical Center+, Maastricht, Netherlands
| | - Gordon W Blair
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Maud van Dinther
- Department of Neurology and School for Cardiovascular Diseases, Maastricht University Medical Center+, Maastricht, Netherlands
| | - Carmen Arteaga Reyes
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK; UK Dementia Research Institute, University of Edinburgh, Edinburgh, UK
| | - Daniela Jaime Garcia
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK; UK Dementia Research Institute, University of Edinburgh, Edinburgh, UK
| | - Laurien Onkenhout
- Department of Neurology, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht, Netherlands
| | - Karolina A Wartolowska
- Wolfson Centre for Prevention of Stroke and Dementia, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Michael J Thrippleton
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK; UK Dementia Research Institute, University of Edinburgh, Edinburgh, UK
| | - Agniete Kampaite
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK; UK Dementia Research Institute, University of Edinburgh, Edinburgh, UK
| | - Marco Duering
- Institute for Stroke and Dementia Research, University Hospital, LMU Munich, Munich, Germany; Medical Image Analysis Center and Department of Biomedical Engineering, University of Basel, Basel, Switzerland
| | - Julie Staals
- Department of Neurology and School for Cardiovascular Diseases, Maastricht University Medical Center+, Maastricht, Netherlands
| | | | - Keith W Muir
- School of Psychology and Neuroscience, University of Glasgow, Queen Elizabeth University Hospital, Glasgow, UK
| | - Martin Middeke
- Hypertoniezentrum München, Excellence Centre of the European Society of Hypertension, Munich, Germany
| | - Bo Norrving
- Department of Clinical Sciences Lund, Neurology, Skåne University Hospital, Lund University, Lund, Sweden
| | | | - Ulrich Mansmann
- Institute for Medical Information Processing, Biometry, and Epidemiology, LMU Munich, Munich, Germany
| | - Peter M Rothwell
- Wolfson Centre for Prevention of Stroke and Dementia, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Fergus N Doubal
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK; UK Dementia Research Institute, University of Edinburgh, Edinburgh, UK
| | - Robert van Oostenbrugge
- Department of Neurology and School for Cardiovascular Diseases, Maastricht University Medical Center+, Maastricht, Netherlands
| | - Geert Jan Biessels
- Department of Neurology, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht, Netherlands
| | - Alastair J S Webb
- Wolfson Centre for Prevention of Stroke and Dementia, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Joanna M Wardlaw
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK; UK Dementia Research Institute, University of Edinburgh, Edinburgh, UK
| | - Martin Dichgans
- Institute for Stroke and Dementia Research, University Hospital, LMU Munich, Munich, Germany; Munich Cluster for Systems Neurology, Munich, Germany; German Center for Neurodegenerative Diseases, Munich, Germany; German Centre for Cardiovascular Research, Munich, Germany.
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5
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Hou X, Guo P, Wang P, Liu P, Lin DDM, Fan H, Li Y, Wei Z, Lin Z, Jiang D, Jin J, Kelly C, Pillai JJ, Huang J, Pinho MC, Thomas BP, Welch BG, Park DC, Patel VM, Hillis AE, Lu H. Deep-learning-enabled brain hemodynamic mapping using resting-state fMRI. NPJ Digit Med 2023; 6:116. [PMID: 37344684 PMCID: PMC10284915 DOI: 10.1038/s41746-023-00859-y] [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: 10/10/2022] [Accepted: 06/09/2023] [Indexed: 06/23/2023] Open
Abstract
Cerebrovascular disease is a leading cause of death globally. Prevention and early intervention are known to be the most effective forms of its management. Non-invasive imaging methods hold great promises for early stratification, but at present lack the sensitivity for personalized prognosis. Resting-state functional magnetic resonance imaging (rs-fMRI), a powerful tool previously used for mapping neural activity, is available in most hospitals. Here we show that rs-fMRI can be used to map cerebral hemodynamic function and delineate impairment. By exploiting time variations in breathing pattern during rs-fMRI, deep learning enables reproducible mapping of cerebrovascular reactivity (CVR) and bolus arrival time (BAT) of the human brain using resting-state CO2 fluctuations as a natural "contrast media". The deep-learning network is trained with CVR and BAT maps obtained with a reference method of CO2-inhalation MRI, which includes data from young and older healthy subjects and patients with Moyamoya disease and brain tumors. We demonstrate the performance of deep-learning cerebrovascular mapping in the detection of vascular abnormalities, evaluation of revascularization effects, and vascular alterations in normal aging. In addition, cerebrovascular maps obtained with the proposed method exhibit excellent reproducibility in both healthy volunteers and stroke patients. Deep-learning resting-state vascular imaging has the potential to become a useful tool in clinical cerebrovascular imaging.
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Affiliation(s)
- Xirui Hou
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Pengfei Guo
- Department of Computer Science, Johns Hopkins University, Baltimore, MD, USA
| | - Puyang Wang
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Peiying Liu
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Doris D M Lin
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Hongli Fan
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yang Li
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Zhiliang Wei
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Zixuan Lin
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Dengrong Jiang
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jin Jin
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Catherine Kelly
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jay J Pillai
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Judy Huang
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Marco C Pinho
- Department of Radiology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Binu P Thomas
- Department of Radiology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Babu G Welch
- Department of Neurologic Surgery, UT Southwestern Medical Center, Dallas, TX, USA
- Center for Vital Longevity, School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, TX, USA
| | - Denise C Park
- Center for Vital Longevity, School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, TX, USA
| | - Vishal M Patel
- Department of Computer Science, Johns Hopkins University, Baltimore, MD, USA
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Argye E Hillis
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Hanzhang Lu
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA.
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6
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Marchena-Romero KJ, Ji X, Sommer R, Centen A, Ramirez J, Poulin JM, Mikulis D, Thrippleton M, Wardlaw J, Lim A, Black SE, MacIntosh BJ. Examining temporal features of BOLD-based cerebrovascular reactivity in clinical populations. Front Neurol 2023; 14:1199805. [PMID: 37396759 PMCID: PMC10310960 DOI: 10.3389/fneur.2023.1199805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 05/25/2023] [Indexed: 07/04/2023] Open
Abstract
Background Conventional cerebrovascular reactivity (CVR) estimation has demonstrated that many brain diseases and/or conditions are associated with altered CVR. Despite the clinical potential of CVR, characterization of temporal features of a CVR challenge remains uncommon. This work is motivated by the need to develop CVR parameters that characterize individual temporal features of a CVR challenge. Methods Data were collected from 54 adults and recruited based on these criteria: (1) Alzheimer's disease diagnosis or subcortical Vascular Cognitive Impairment, (2) sleep apnea, and (3) subjective cognitive impairment concerns. We investigated signal changes in blood oxygenation level dependent (BOLD) contrast images with respect to hypercapnic and normocapnic CVR transition periods during a gas manipulation paradigm. We developed a model-free, non-parametric CVR metric after considering a range of responses through simulations to characterize BOLD signal changes that occur when transitioning from normocapnia to hypercapnia. The non-parametric CVR measure was used to examine regional differences across the insula, hippocampus, thalamus, and centrum semiovale. We also examined the BOLD signal transition from hypercapnia back to normocapnia. Results We found a linear association between isolated temporal features of successive CO2 challenges. Our study concluded that the transition rate from hypercapnia to normocapnia was significantly associated with the second CVR response across all regions of interest (p < 0.001), and this association was highest in the hippocampus (R2 = 0.57, p < 0.0125). Conclusion This study demonstrates that it is feasible to examine individual responses associated with normocapnic and hypercapnic transition periods of a BOLD-based CVR experiment. Studying these features can provide insight on between-subject differences in CVR.
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Affiliation(s)
- Kayley-Jasmin Marchena-Romero
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
- Hurvitz Brain Sciences Program, Sunnybrook Research Institute, Toronto, ON, Canada
| | - Xiang Ji
- Hurvitz Brain Sciences Program, Sunnybrook Research Institute, Toronto, ON, Canada
- Dr. Sandra Black Centre for Brain Resilience and Recovery, Toronto, ON, Canada
| | - Rosa Sommer
- Hurvitz Brain Sciences Program, Sunnybrook Research Institute, Toronto, ON, Canada
- Dr. Sandra Black Centre for Brain Resilience and Recovery, Toronto, ON, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
| | - Andrew Centen
- Hurvitz Brain Sciences Program, Sunnybrook Research Institute, Toronto, ON, Canada
| | - Joel Ramirez
- Hurvitz Brain Sciences Program, Sunnybrook Research Institute, Toronto, ON, Canada
- Dr. Sandra Black Centre for Brain Resilience and Recovery, Toronto, ON, Canada
| | - Joshua M. Poulin
- Hurvitz Brain Sciences Program, Sunnybrook Research Institute, Toronto, ON, Canada
- Dr. Sandra Black Centre for Brain Resilience and Recovery, Toronto, ON, Canada
| | - David Mikulis
- Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
- Division of Neuroradiology, Joint Department of Medical Imaging, University Health Network, Toronto, ON, Canada
- Department of Medical Imaging, University of Toronto, Toronto, ON, Canada
| | - Michael Thrippleton
- Brain Research Imaging Centre, Centre for Clinical Brain Sciences, UK Dementia Research Institute Centre, The University of Edinburgh, Edinburgh, United Kingdom
| | - Joanna Wardlaw
- Brain Research Imaging Centre, Centre for Clinical Brain Sciences, UK Dementia Research Institute Centre, The University of Edinburgh, Edinburgh, United Kingdom
| | - Andrew Lim
- Hurvitz Brain Sciences Program, Sunnybrook Research Institute, Toronto, ON, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
| | - Sandra E. Black
- Hurvitz Brain Sciences Program, Sunnybrook Research Institute, Toronto, ON, Canada
- Dr. Sandra Black Centre for Brain Resilience and Recovery, Toronto, ON, Canada
| | - Bradley J. MacIntosh
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
- Hurvitz Brain Sciences Program, Sunnybrook Research Institute, Toronto, ON, Canada
- Dr. Sandra Black Centre for Brain Resilience and Recovery, Toronto, ON, Canada
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7
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Williams RJ, Specht JL, Mazerolle EL, Lebel RM, MacDonald ME, Pike GB. Correspondence between BOLD fMRI task response and cerebrovascular reactivity across the cerebral cortex. Front Physiol 2023; 14:1167148. [PMID: 37228813 PMCID: PMC10203231 DOI: 10.3389/fphys.2023.1167148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 04/24/2023] [Indexed: 05/27/2023] Open
Abstract
BOLD sensitivity to baseline perfusion and blood volume is a well-acknowledged fMRI confound. Vascular correction techniques based on cerebrovascular reactivity (CVR) might reduce variance due to baseline cerebral blood volume, however this is predicated on an invariant linear relationship between CVR and BOLD signal magnitude. Cognitive paradigms have relatively low signal, high variance and involve spatially heterogenous cortical regions; it is therefore unclear whether the BOLD response magnitude to complex paradigms can be predicted by CVR. The feasibility of predicting BOLD signal magnitude from CVR was explored in the present work across two experiments using different CVR approaches. The first utilized a large database containing breath-hold BOLD responses and 3 different cognitive tasks. The second experiment, in an independent sample, calculated CVR using the delivery of a fixed concentration of carbon dioxide and a different cognitive task. An atlas-based regression approach was implemented for both experiments to evaluate the shared variance between task-invoked BOLD responses and CVR across the cerebral cortex. Both experiments found significant relationships between CVR and task-based BOLD magnitude, with activation in the right cuneus (R 2 = 0.64) and paracentral gyrus (R 2 = 0.71), and the left pars opercularis (R 2 = 0.67), superior frontal gyrus (R 2 = 0.62) and inferior parietal cortex (R 2 = 0.63) strongly predicted by CVR. The parietal regions bilaterally were highly consistent, with linear regressions significant in these regions for all four tasks. Group analyses showed that CVR correction increased BOLD sensitivity. Overall, this work suggests that BOLD signal response magnitudes to cognitive tasks are predicted by CVR across different regions of the cerebral cortex, providing support for the use of correction based on baseline vascular physiology.
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Affiliation(s)
- Rebecca J. Williams
- Faculty of Health, School of Human Services, Charles Darwin University, Darwin, NT, Australia
| | - Jacinta L. Specht
- Department of Clinical Neuroscience, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Erin L. Mazerolle
- Departments of Psychology and Computer Science, St. Francis Xavier University, Antigonish, NS, Canada
| | - R. Marc Lebel
- Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- GE HealthCare, Calgary, AB, Canada
| | - M. Ethan MacDonald
- Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Department of Biomedical Engineering, Schulich School of Engineering, University of Calgary, Calgary, AB, Canada
- Department of Electrical and Software Engineering, Schulich School of Engineering, University of Calgary, Calgary, AB, Canada
| | - G. Bruce Pike
- Department of Clinical Neuroscience, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
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8
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Ogoh S, Watanabe H, Saito S, Fisher JP, Iwamoto E. Can Alterations in Cerebrovascular CO 2 Reactivity Be Identified Using Transfer Function Analysis without the Requirement for Carbon Dioxide Inhalation? J Clin Med 2023; 12:jcm12062441. [PMID: 36983441 PMCID: PMC10051076 DOI: 10.3390/jcm12062441] [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: 02/02/2023] [Revised: 03/09/2023] [Accepted: 03/21/2023] [Indexed: 03/30/2023] Open
Abstract
The present study aimed to examine the validity of a novel method to assess cerebrovascular carbon dioxide (CO2) reactivity (CVR) that does not require a CO2 inhalation challenge, e.g., for use in patients with respiratory disease or the elderly, etc. In twenty-one healthy participants, CVR responses to orthostatic stress (50° head-up tilt, HUT) were assessed using two methods: (1) the traditional CO2 inhalation method, and (2) transfer function analysis (TFA) between middle cerebral artery blood velocity (MCA V) and predicted arterial partial pressure of CO2 (PaCO2) during spontaneous respiration. During HUT, MCA V steady-state (i.e., magnitude) and MCA V onset (i.e., time constant) responses to CO2 inhalation were decreased (p < 0.001) and increased (p = 0.001), respectively, indicative of attenuated CVR. In contrast, TFA gain in the very low-frequency range (VLF, 0.005-0.024 Hz) was unchanged, while the TFA phase in the VLF approached zero during HUT (-0.38 ± 0.59 vs. 0.31 ± 0.78 radians, supine vs. HUT; p = 0.003), indicative of a shorter time (i.e., improved) response of CVR. These findings indicate that CVR metrics determined by TFA without a CO2 inhalation do not track HUT-evoked reductions in CVR identified using CO2 inhalation, suggesting that enhanced cerebral blood flow response to a change in CO2 using CO2 inhalation is necessary to assess CVR adequately.
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Affiliation(s)
- Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Kawagoe 350-8585, Japan
- Neurovascular Research Laboratory, University of South Wales, Pontypridd CF37 1DL, UK
| | - Hironori Watanabe
- Department of Biomedical Engineering, Toyo University, Kawagoe 350-8585, Japan
| | - Shotaro Saito
- Department of Biomedical Engineering, Toyo University, Kawagoe 350-8585, Japan
| | - James P Fisher
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1023, New Zealand
| | - Erika Iwamoto
- School of Health Sciences, Sapporo Medical University, Sapporo 060-8556, Japan
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9
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Zvolanek KM, Moia S, Dean JN, Stickland RC, Caballero-Gaudes C, Bright MG. Comparing end-tidal CO 2, respiration volume per time (RVT), and average gray matter signal for mapping cerebrovascular reactivity amplitude and delay with breath-hold task BOLD fMRI. Neuroimage 2023; 272:120038. [PMID: 36958618 DOI: 10.1016/j.neuroimage.2023.120038] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 02/27/2023] [Accepted: 03/14/2023] [Indexed: 03/25/2023] Open
Abstract
Cerebrovascular reactivity (CVR), defined as the cerebral blood flow response to a vasoactive stimulus, is an imaging biomarker with demonstrated utility in a range of diseases and in typical development and aging processes. A robust and widely implemented method to map CVR involves using a breath-hold task during a BOLD fMRI scan. Recording end-tidal CO2 (PETCO2) changes during the breath-hold task is recommended to be used as a reference signal for modeling CVR amplitude in standard units (%BOLD/mmHg) and CVR delay in seconds. However, obtaining reliable PETCO2 recordings requires equipment and task compliance that may not be achievable in all settings. To address this challenge, we investigated two alternative reference signals to map CVR amplitude and delay in a lagged general linear model (lagged-GLM) framework: respiration volume per time (RVT) and average gray matter BOLD response (GM-BOLD). In 8 healthy adults with multiple scan sessions, we compare spatial agreement of CVR maps from RVT and GM-BOLD to those generated with PETCO2. We define a threshold to determine whether a PETCO2 recording has "sufficient" quality for CVR mapping and perform these comparisons in 16 datasets with sufficient PETCO2 and 6 datasets with insufficient PETCO2. When PETCO2 quality is sufficient, both RVT and GM-BOLD produce CVR amplitude maps that are nearly identical to those from PETCO2 (after accounting for differences in scale), with the caveat they are not in standard units to facilitate between-group comparisons. CVR delays are comparable to PETCO2 with an RVT regressor but may be underestimated with the average GM-BOLD regressor. Importantly, when PETCO2 quality is insufficient, RVT and GM-BOLD CVR recover reasonable CVR amplitude and delay maps, provided the participant attempted the breath-hold task. Therefore, our framework offers a solution for achieving high quality CVR maps in both retrospective and prospective studies where sufficient PETCO2 recordings are not available and especially in populations where obtaining reliable measurements is a known challenge (e.g., children). Our results have the potential to improve the accessibility of CVR mapping and to increase the prevalence of this promising metric of vascular health.
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Affiliation(s)
- Kristina M Zvolanek
- Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA; Department of Biomedical Engineering, McCormick School of Engineering and Applied Sciences, Northwestern University, Evanston, IL, USA.
| | - Stefano Moia
- Basque Center on Cognition, Brain and Language, Donostia, Gipuzkoa, Spain; Medical Imaging Processing Lab (MIP:Lab), Neuro-X institute, EPFL, Geneva, Switzerland
| | - Joshua N Dean
- Department of Biomedical Engineering, McCormick School of Engineering and Applied Sciences, Northwestern University, Evanston, IL, USA
| | - Rachael C Stickland
- Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | | | - Molly G Bright
- Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA; Department of Biomedical Engineering, McCormick School of Engineering and Applied Sciences, Northwestern University, Evanston, IL, USA
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10
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Wang C, Reid G, Mackay CE, Hayes G, Bulte DP, Suri S. A Systematic Review of the Association Between Dementia Risk Factors and Cerebrovascular Reactivity. Neurosci Biobehav Rev 2023; 148:105140. [PMID: 36944391 DOI: 10.1016/j.neubiorev.2023.105140] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 02/15/2023] [Accepted: 03/15/2023] [Indexed: 03/23/2023]
Abstract
Cumulative evidence suggests that impaired cerebrovascular reactivity (CVR), a regulatory response critical for maintaining neuronal health, is amongst the earliest pathological changes in dementia. However, we know little about how CVR is affected by dementia risk, prior to disease onset. Understanding this relationship would improve our knowledge of disease pathways and help inform preventative interventions. This systematic review investigates 59 studies examining how CVR (measured by magnetic resonance imaging) is affected by modifiable, non-modifiable, and clinical risk factors for dementia. We report that non-modifiable risk (older age and apolipoprotein ε4), some modifiable factors (diabetes, traumatic brain injury, hypertension) and some clinical factors (stroke, carotid artery occlusion, stenosis) were consistently associated with reduced CVR. We also note a lack of conclusive evidence on how other behavioural factors such as physical inactivity, obesity, or depression, affect CVR. This review explores the biological mechanisms underpinning these brain- behaviour associations, highlights evident gaps in the literature, and identifies the risk factors that could be managed to preserve CVR in an effort to prevent dementia.
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Affiliation(s)
- Congxiyu Wang
- Department of Psychiatry, University of Oxford, UK; Wellcome Centre for Integrative Neuroimaging, University of Oxford, UK
| | - Graham Reid
- Department of Psychiatry, University of Oxford, UK; Department of Experimental Psychology, University of Oxford, UK
| | - Clare E Mackay
- Department of Psychiatry, University of Oxford, UK; Wellcome Centre for Integrative Neuroimaging, University of Oxford, UK
| | - Genevieve Hayes
- Institute of Biomedical Engineering, University of Oxford, UK
| | - Daniel P Bulte
- Institute of Biomedical Engineering, University of Oxford, UK
| | - Sana Suri
- Department of Psychiatry, University of Oxford, UK; Wellcome Centre for Integrative Neuroimaging, University of Oxford, UK.
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11
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Xiu C, Ni D, Zhao J, Yu Y. Analysis of characteristics of intracranial cavernous angioma and bleeding factors in middle-aged and elderly patients. Front Neurol 2023; 14:1084911. [PMID: 36815003 PMCID: PMC9939627 DOI: 10.3389/fneur.2023.1084911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 01/04/2023] [Indexed: 02/09/2023] Open
Abstract
Objective Intracranial cavernous angioma (ICA) is a cerebrovascular malformation. It causes local neurological dysfunction, epilepsy, intracranial hemorrhage (ICH) and other symptoms, seriously affecting the safety of patients. This study analyzed middle-aged and elderly patients with ICA in our hospital, summarized the characteristics of the disease and investigated the related factors of ICH. Methods We conducted a retrospective analysis of 120 middle-aged and elderly patients who were diagnosed with ICA by magnetic resonance imaging in our hospital from March 2018 to September 2021. The cases were assigned to either a bleeding group (i.e., the experimental group) or a non-bleeding group (i.e., the control group). The characteristics of the disease, including gender, age, number of lesions, form and symptoms of onset, distribution of lesions, blood supply vessels in the lesion area, size of the lesion and presence of bleeding, were summarized and analyzed. The relationship between these factors and ICH was investigated, and the data were analyzed using SPSS 25.0 software. Results There were 56 cases in the experimental group and 64 cases in the control group. A univariate analysis showed that gender, age, body mass index, blood lipids, number of lesions, course of the disease, onset of symptoms and disease characteristics were not associated with ICH in the middle-aged and elderly patients with ICA (P > 0.05). The maximum diameter, volume, location and blood supply area of the lesions were related to ICA complicated with ICH (P < 0.05). A multivariate unconditional logistic regression analysis revealed that the maximum diameter, volume, location and blood supply area of the lesions were independent risk factors for ICH in the middle-aged and elderly patients with ICA. The odds ratio (OR) of the maximum diameter of the lesion was 4.410, the OR of the lesion volume was 7.316, the OR of the lesion site was 7.470, and the OR of the blood supply area was 1.6588. Conclusion Intracranial cavernous angioma lesions in middle-aged and elderly patients occur mainly in the supratentorial area, with a small part located in the infratentorial area. The main form of the disease is chronic recurrence. The occurrence of bleeding is related to the size, location and blood supply of the lesion.
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Affiliation(s)
- Chao Xiu
- Medical Imaging Center, Affiliated Hospital of Beihua University, Jilin City, China
| | - Donghe Ni
- Nuclear Magnetic Resonance Department, Integrated Traditional Chinese and Western Medicine Hospital of Jilin Province, Jilin City, China
| | - Jincui Zhao
- Medical Imaging Center, Affiliated Hospital of Beihua University, Jilin City, China
| | - Yang Yu
- Medical Imaging Center, Affiliated Hospital of Beihua University, Jilin City, China
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12
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Glass Umfleet L, Pommy J, Cohen AD, Allen M, Obarski S, Mason L, Berres H, Franczak M, Wang Y. Decreased Cerebrovascular Reactivity in Mild Cognitive Impairment Phenotypes. J Alzheimers Dis 2023; 94:1503-1513. [PMID: 37424462 DOI: 10.3233/jad-221156] [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] [Indexed: 07/11/2023]
Abstract
BACKGROUND Cerebrovascular health plays an important role in cognitive health in older adults. Cerebrovascular reactivity (CVR), a measure of cerebrovascular health, changes in both normal and pathological aging, and is increasingly being conceptualized as contributory to cognitive decline. Interrogation of this process will yield new insights into cerebrovascular correlates of cognition and neurodegeneration. OBJECTIVE The current study examines CVR using advanced MRI in prodromal dementia states (amnestic and non-amnestic mild cognitive impairment phenotypes; aMCI and naMCI, respectively) and older adult controls. METHODS CVR was assessed in 41 subjects (20 controls, 11 aMCI, 10 naMCI) using multiband multi-echo breath-holding task functional magnetic resonance imaging. Imaging data were preprocessed and analyzed using AFNI. All participants also completed a battery of neuropsychological tests. T-tests and ANOVA/ANCOVA analyses were conducted to compare controls to MCI groups on CVR and cognitive metrics. Partial correlation analyses between CVR derived from regions-of-interest (ROIs) and different cognitive functions were conducted. RESULTS CVR was found to be significantly lower in aMCI and naMCI patients compared to controls. naMCI showed intermediate patterns between aMCI and controls (though aMCI and naMCI groups did not significantly differ). CVR of ROIs were positively correlated with neuropsychological measures of processing speed, executive functioning, and memory. CONCLUSION The findings highlight regional CVR differences in MCI phenotypes compared to controls, where aMCI may have lower CVR than naMCI. Our results suggest possible cerebrovascular abnormalities associated with MCI phenotypes.
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Affiliation(s)
| | - Jessica Pommy
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Alexander D Cohen
- Department of Radiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | | | - Shawn Obarski
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA
- Department of Radiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Lilly Mason
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Halle Berres
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA
| | | | - Yang Wang
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI, USA
- Department of Radiology, Medical College of Wisconsin, Milwaukee, WI, USA
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI, USA
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13
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Sayin ES, Sobczyk O, Poublanc J, Mikulis DJ, Fisher JA, Kuo KHM, Duffin J. Assessment of cerebrovascular function in patients with sickle cell disease using transfer function analysis. Physiol Rep 2022; 10:e15472. [PMID: 36200271 PMCID: PMC9535348 DOI: 10.14814/phy2.15472] [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: 07/04/2022] [Revised: 08/29/2022] [Accepted: 09/01/2022] [Indexed: 11/07/2022] Open
Abstract
In patients with sickle cell disease (SCD), the delivery of oxygen to the brain is compromised by anemia, abnormal rheology, and steno‐occlusive vascular disease. Successful compensation depends on an increase in oxygen supply such as that provided by an increase in cerebral blood flow (CBF). We used magnetic resonance imaging to provide a high‐resolution assessment of the ability of SCD patients to respond to a vasoactive stimulus in middle, anterior, and posterior cerebral artery territories for both white and gray matter. Cerebrovascular reactivity (CVR) was measured as the blood oxygen level dependent signal (a surrogate for CBF) response to an increase in the end tidal partial pressure of CO2 (PETCO2). The dynamic aspect of the response was measured as the time constant of the first order response kinetics (tau). To confirm and support these findings we used an alternative examination of the response, transfer function analysis (TFA), to measure the responsiveness (gain), the speed of response (phase), and the consistency of the response over time (coherence). We tested 34 patients with SCD and compared the results to those of 24 healthy controls participants. The results from a three‐way ANOVA showed that patients with SCD have reduced CVR (p < 0.001) and lower coherence (p < 0.001) in gray matter and white matter and reduced gain in gray matter only (p < 0.001). In terms of the speed of the response to CO2, tau (p < 0.001) and TFA phase (p < 0.001) were increased in SCD patients compared to healthy control subjects. These findings show that the cerebrovascular responsiveness to CO2 in patients with SCD is both decreased and slowed compared to healthy controls.
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Affiliation(s)
- Ece Su Sayin
- Department of PhysiologyUniversity of TorontoTorontoCanada,Departments of Anaesthesia and Pain ManagementUniversity Health NetworkTorontoCanada
| | - Olivia Sobczyk
- Department of PhysiologyUniversity of TorontoTorontoCanada,Departments of Anaesthesia and Pain ManagementUniversity Health NetworkTorontoCanada,Joint Department of Medical Imaging and the Functional Neuroimaging LaboratoryUniversity Health NetworkTorontoCanada
| | - Julien Poublanc
- Joint Department of Medical Imaging and the Functional Neuroimaging LaboratoryUniversity Health NetworkTorontoCanada
| | - David J. Mikulis
- Joint Department of Medical Imaging and the Functional Neuroimaging LaboratoryUniversity Health NetworkTorontoCanada,Institute of Medical SciencesUniversity of TorontoTorontoCanada
| | - Joseph A. Fisher
- Department of PhysiologyUniversity of TorontoTorontoCanada,Departments of Anaesthesia and Pain ManagementUniversity Health NetworkTorontoCanada
| | - Kevin H. M. Kuo
- Division of Medical Oncology and Hematology, Department of MedicineUniversity of TorontoTorontoOntarioCanada
| | - James Duffin
- Department of PhysiologyUniversity of TorontoTorontoCanada,Departments of Anaesthesia and Pain ManagementUniversity Health NetworkTorontoCanada
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14
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Vlisides PE, Mentz G, Leis AM, Colquhoun D, McBride J, Naik BI, Dunn LK, Aziz MF, Vagnerova K, Christensen C, Pace NL, Horn J, Cummings K, Cywinski J, Akkermans A, Kheterpal S, Moore LE, Mashour GA. Carbon Dioxide, Blood Pressure, and Perioperative Stroke: A Retrospective Case-Control Study. Anesthesiology 2022; 137:434-445. [PMID: 35960872 PMCID: PMC10324342 DOI: 10.1097/aln.0000000000004354] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
BACKGROUND The relationship between intraoperative physiology and postoperative stroke is incompletely understood. Preliminary data suggest that either hypo- or hypercapnia coupled with reduced cerebrovascular inflow (e.g., due to hypotension) can lead to ischemia. This study tested the hypothesis that the combination of intraoperative hypotension and either hypo- or hypercarbia is associated with postoperative ischemic stroke. METHODS We conducted a retrospective, case-control study via the Multicenter Perioperative Outcomes Group. Noncardiac, nonintracranial, and nonmajor vascular surgical cases (18 yr or older) were extracted from five major academic centers between January 2004 and December 2015. Ischemic stroke cases were identified via manual chart review and matched to controls (1:4). Time and reduction below key mean arterial blood pressure thresholds (less than 55 mmHg, less than 60 mmHg, less than 65 mmHg) and outside of specific end-tidal carbon dioxide thresholds (30 mmHg or less, 35 mmHg or less, 45 mmHg or greater) were calculated based on total area under the curve. The association between stroke and total area under the curve values was then tested while adjusting for relevant confounders. RESULTS In total, 1,244,881 cases were analyzed. Among the cases that screened positive for stroke (n = 1,702), 126 were confirmed and successfully matched with 500 corresponding controls. Total area under the curve was significantly associated with stroke for all thresholds tested, with the strongest combination observed with mean arterial pressure less than 55 mmHg (adjusted odds ratio per 10 mmHg-min, 1.17 [95% CI, 1.10 to 1.23], P < 0.0001) and end-tidal carbon dioxide 45 mmHg or greater (adjusted odds ratio per 10 mmHg-min, 1.11 [95% CI, 1.10 to 1.11], P < 0.0001). There was no interaction effect observed between blood pressure and carbon dioxide. CONCLUSIONS Intraoperative hypotension and carbon dioxide dysregulation may each independently increase postoperative stroke risk. EDITOR’S PERSPECTIVE
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Affiliation(s)
- Phillip E. Vlisides
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI USA 48109
- Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI USA 48109
| | - Graciela Mentz
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI USA 48109
| | - Aleda M. Leis
- Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, MI USA 48109
| | - Douglas Colquhoun
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI USA 48109
| | - Jonathon McBride
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI USA 48109
| | - Bhiken I. Naik
- Department of Anesthesiology, University of Virginia School of Medicine, Charlottesville, VA USA 22908
- Department of Neurological Surgery, University of Virginia School of Medicine, Charlottesville, VA USA 22908
| | - Lauren K. Dunn
- Department of Anesthesiology, University of Virginia School of Medicine, Charlottesville, VA USA 22908
| | - Michael F. Aziz
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR USA 97239
| | - Kamila Vagnerova
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, OR USA 97239
| | - Clint Christensen
- Department of Anesthesiology, University of Utah School of Medicine, Salt Lake City, UT USA 84132
| | - Nathan L. Pace
- Department of Anesthesiology, University of Utah School of Medicine, Salt Lake City, UT USA 84132
| | - Jeffrey Horn
- Department of Anesthesiology, University of Utah School of Medicine, Salt Lake City, UT USA 84132
| | | | - Jacek Cywinski
- Anesthesiology Institute, Cleveland Clinic, OH USA 44195
| | - Annemarie Akkermans
- Department of Anesthesiology, University Medical Center Utrecht, Netherlands
| | - Sachin Kheterpal
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI USA 48109
| | - Laurel E. Moore
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI USA 48109
| | - George A. Mashour
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI USA 48109
- Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI USA 48109
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI USA
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15
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Differential regional cerebrovascular reactivity to end-tidal gas combinations commonly seen during anaesthesia: A blood oxygenation level-dependent MRI observational study in awake adult subjects. Ugeskr Laeger 2022; 39:774-784. [PMID: 35852545 DOI: 10.1097/eja.0000000000001716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Regional cerebrovascular reactivity (rCVR) is highly variable in the human brain as measured by blood oxygenation level-dependent (BOLD) MRI to changes in both end-tidal CO 2 and O 2 . OBJECTIVES We examined awake participants under carefully controlled end-tidal gas concentrations to assess how regional CVR changes may present with end-tidal gas changes seen commonly with anaesthesia. DESIGN Observational study. SETTING Tertiary care centre, Winnipeg, Canada. The imaging for the study occurred in 2019. SUBJECTS Twelve healthy adult subjects. INTERVENTIONS Cerebral BOLD response was studied under two end-tidal gas paradigms. First end-tidal oxygen (ETO 2 ) maintained stable whereas ETCO 2 increased incrementally from hypocapnia to hypercapnia (CO 2 ramp); second ETCO 2 maintained stable whereas ETO 2 increased from normoxia to hyperoxia (O 2 ramp). BOLD images were modeled with end-tidal gas sequences split into two equal segments to examine regional CVR. MAIN OUTCOME MEASURES The voxel distribution comparing hypocapnia to mild hypercapnia and mild hyperoxia (mean F I O 2 = 0.3) to marked hyperoxia (mean F I O 2 = 0.7) were compared in a paired fashion ( P < 0.005 to reach threshold for voxel display). Additionally, type analysis was conducted on CO 2 ramp data. This stratifies the BOLD response to the CO 2 ramp into four categories of CVR slope based on segmentation (type A; +/+slope: normal response, type B +/-, type C -/-: intracranial steal, type D -/+.) Types B to D represent altered responses to the CO 2 stimulus. RESULTS Differential regional responsiveness was seen for both end-tidal gases. Hypocapnic regional CVR was more marked than hypercapnic CVR in 0.3% of voxels examined ( P < 0.005, paired comparison); the converse occurred in 2.3% of voxels. For O 2 , mild hyperoxia had more marked CVR in 0.2% of voxels compared with greater hyperoxia; the converse occurred in 0.5% of voxels. All subjects had altered regional CO 2 response based on Type Analysis ranging from 4 ± 2 to 7 ± 3% of voxels. CONCLUSION In awake subjects, regional differences and abnormalities in CVR were observed with changes in end-tidal gases common during the conduct of anaesthesia. On the basis of these findings, consideration could be given to minimising regional CVR fluctuations in patients-at-risk of neurological complications by tighter control of end-tidal gases near the individual's resting values.
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16
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Forté S, Sobczyk O, Poublanc J, Duffin J, Hare GMT, Fisher JA, Mikulis D, Kuo KHM. Sickle cell cerebrovascular reactivity to a CO2 stimulus: Too little, too slow. Front Physiol 2022; 13:886807. [PMID: 36060689 PMCID: PMC9437621 DOI: 10.3389/fphys.2022.886807] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 06/30/2022] [Indexed: 11/13/2022] Open
Abstract
Background: Despite increased cerebral blood flow (CBF), cerebral infarcts occur in patients with sickle cell disease (SCD). This suggests increased CBF does not meet metabolic demand possibly due to compromised cerebral vasodilatory response. Hypothesis: In adult SCD patients, cerebrovascular reactivity (CVR) and speed of vasodilatory response (tau) to a standardized vasodilatory stimulus, are reduced compared to normal subjects. Methods: Functional brain imaging performed as part of routine care in adult SCD patients without known large vessel cerebral vasculopathy was reviewed retrospectively. CVR was calculated as the change in CBF measured as the blood-oxygenation-level-dependent (BOLD)-magnetic resonance imaging signal, in response to a standard vasoactive stimulus of carbon dioxide (CO2). The tau corresponding to the best fit between the convolved end-tidal partial pressures of CO2 and BOLD signal was defined as the speed of vascular response. CVR and tau were normalized using a previously generated atlas of 42 healthy controls. Results: Fifteen patients were included. CVR was reduced in grey and white matter (mean Z-score for CVR −0.5 [−1.8 to 0.3] and −0.6 [−2.3 to 0.7], respectively). Tau Z-scores were lengthened in grey and white matter (+0.9 [−0.5 to 3.3] and +0.8 [−0.7 to 2.7], respectively). Hematocrit was the only significant independent predictor of CVR on multivariable regression. Conclusion: Both measures of cerebrovascular health (CVR and tau) in SCD patients were attenuated compared to normal controls. These findings show that CVR represents a promising tool to assess disease state, stroke risk, and therapeutic efficacy of treatments in SCD and merits further investigation.
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Affiliation(s)
- Stéphanie Forté
- Division of Medical Oncology and Hematology, Departement of Medicine, Centre Hospitalier de l'Université de Montréal, Montréal, QC, Canada
- Division of Medical Oncology and Hematology, Department of Medicine, University Health Network, Toronto, ON, Canada
- Division of Hematology, Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - Olivia Sobczyk
- Joint Department of Medical Imaging, University Health Network, Toronto, ON, Canada
- Department of Anaesthesia and Pain Medicine, University Health Network, Toronto, ON, Canada
| | - Julien Poublanc
- Joint Department of Medical Imaging, University Health Network, Toronto, ON, Canada
| | - James Duffin
- The Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Gregory M. T. Hare
- The Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Department of Anesthesia, St. Michael’s Hospital, Toronto, ON, Canada
| | - Joseph Arnold Fisher
- Department of Anaesthesia and Pain Medicine, University Health Network, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - David Mikulis
- Joint Department of Medical Imaging, University Health Network, Toronto, ON, Canada
| | - Kevin H. M. Kuo
- Division of Medical Oncology and Hematology, Department of Medicine, University Health Network, Toronto, ON, Canada
- Division of Hematology, Department of Medicine, University of Toronto, Toronto, ON, Canada
- Institute of Health Policy, Management and Evaluation, Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
- *Correspondence: Kevin H. M. Kuo,
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17
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Zhao MY, Fan AP, Chen DYT, Ishii Y, Khalighi MM, Moseley M, Steinberg GK, Zaharchuk G. Using arterial spin labeling to measure cerebrovascular reactivity in Moyamoya disease: Insights from simultaneous PET/MRI. J Cereb Blood Flow Metab 2022; 42:1493-1506. [PMID: 35236136 PMCID: PMC9274857 DOI: 10.1177/0271678x221083471] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cerebrovascular reactivity (CVR) reflects the CBF change to meet different physiological demands. The reference CVR technique is PET imaging with vasodilators but is inaccessible to most patients. DSC can measure transit time to evaluate patients suspected of stroke, but the use of gadolinium may cause side-effects. Arterial spin labeling (ASL) is a non-invasive MRI technique for CBF measurements. Here, we investigate the effectiveness of ASL with single and multiple post labeling delays (PLD) to replace PET and DSC for CVR and transit time mapping in 26 Moyamoya patients. Images were collected using simultaneous PET/MRI with acetazolamide. CVR, CBF, arterial transit time (ATT), and time-to-maximum (Tmax) were measured in different flow territories. Results showed that CVR was lower in occluded regions than normal regions (by 68 ± 12%, 52 ± 5%, and 56 ± 9%, for PET, single- and multi-PLD PCASL, respectively, all p < 0.05). Multi-PLD PCASL correlated slightly higher with PET (CCC = 0.36 and 0.32 in affected and unaffected territories respectively). Vasodilation caused ATT to reduce by 4.5 ± 3.1% (p < 0.01) in occluded regions. ATT correlated significantly with Tmax (R2 > 0.35, p < 0.01). Therefore, multi-PLD ASL is recommended for CVR studies due to its high agreement with the reference PET technique and the capability of measuring transit time.
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Affiliation(s)
- Moss Y Zhao
- Department of Radiology, Stanford University, Stanford, CA, USA
| | - Audrey P Fan
- Department of Biomedical Engineering, University of California Davis, Davis, CA, USA.,Department of Neurology, University of California Davis, Davis, CA, USA
| | - David Yen-Ting Chen
- Department of Medical Imaging, Taipei Medical University - Shuan-Ho Hospital, New Taipei City.,Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei
| | - Yosuke Ishii
- Department of Neurosurgery, Tokyo Medical and Dental University, Tokyo, Japan
| | | | - Michael Moseley
- Department of Radiology, Stanford University, Stanford, CA, USA
| | - Gary K Steinberg
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
| | - Greg Zaharchuk
- Department of Radiology, Stanford University, Stanford, CA, USA
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18
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Voss MW, Jain S. Getting Fit to Counteract Cognitive Aging: Evidence and Future Directions. Physiology (Bethesda) 2022; 37:0. [PMID: 35001656 PMCID: PMC9191193 DOI: 10.1152/physiol.00038.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Physical activity has shown tremendous promise for counteracting cognitive aging, but also tremendous variability in cognitive benefits. We describe evidence for how exercise affects cognitive and brain aging, and whether cardiorespiratory fitness is a key factor. We highlight a brain network framework as a valuable paradigm for the mechanistic insight needed to tailor physical activity for cognitive benefits.
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Affiliation(s)
- Michelle W. Voss
- 1Department of Psychological and Brain Sciences, University of Iowa, Iowa City, Iowa,2Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, Iowa,3Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa
| | - Shivangi Jain
- 1Department of Psychological and Brain Sciences, University of Iowa, Iowa City, Iowa
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19
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Vestergaard MB, Frederiksen JL, Larsson HBW, Cramer SP. Cerebrovascular Reactivity and Neurovascular Coupling in Multiple Sclerosis-A Systematic Review. Front Neurol 2022; 13:912828. [PMID: 35720104 PMCID: PMC9198441 DOI: 10.3389/fneur.2022.912828] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 05/04/2022] [Indexed: 11/25/2022] Open
Abstract
The inflammatory processes observed in the central nervous system in multiple sclerosis (MS) could damage the endothelium of the cerebral vessels and lead to a dysfunctional regulation of vessel tonus and recruitment, potentially impairing cerebrovascular reactivity (CVR) and neurovascular coupling (NVC). Impaired CVR or NVC correlates with declining brain health and potentially plays a causal role in the development of neurodegenerative disease. Therefore, we examined studies on CVR or NVC in MS patients to evaluate the evidence for impaired cerebrovascular function as a contributing disease mechanism in MS. Twenty-three studies were included (12 examined CVR and 11 examined NVC). Six studies found no difference in CVR response between MS patients and healthy controls. Five studies observed reduced CVR in patients. This discrepancy can be because CVR is mainly affected after a long disease duration and therefore is not observed in all patients. All studies used CO2 as a vasodilating stimulus. The studies on NVC demonstrated diverse results; hence a conclusion that describes all the published observations is difficult to find. Future studies using quantitative techniques and larger study samples are needed to elucidate the discrepancies in the reported results.
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Affiliation(s)
- Mark B Vestergaard
- Functional Imaging Unit, Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital Rigshospitalet, Glostrup, Denmark
| | - Jette L Frederiksen
- Danish Multiple Sclerosis Center, Department of Neurology, Copenhagen University Hospital Rigshospitalet, Glostrup, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark
| | - Henrik B W Larsson
- Functional Imaging Unit, Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital Rigshospitalet, Glostrup, Denmark.,Danish Multiple Sclerosis Center, Department of Neurology, Copenhagen University Hospital Rigshospitalet, Glostrup, Denmark
| | - Stig P Cramer
- Functional Imaging Unit, Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital Rigshospitalet, Glostrup, Denmark
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20
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Yew B, Jang JY, Dutt S, Li Y, Sible IJ, Gaubert A, Ho JK, Blanken AE, Marshall A, Shao X, Wang DJJ, Nation DA. Cerebrovascular reactivity deficits in cognitively unimpaired older adults: vasodilatory versus vasoconstrictive responses. Neurobiol Aging 2022; 113:55-62. [PMID: 35325813 PMCID: PMC10958374 DOI: 10.1016/j.neurobiolaging.2022.02.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 01/27/2022] [Accepted: 02/16/2022] [Indexed: 01/16/2023]
Abstract
Cerebrovascular reactivity (CVR) deficits may index vulnerability to vascular brain injury and cognitive impairment, but findings on age-related changes in CVR have been mixed, and no studies to date have directly compared age-related changes in CVR to hypercapnia versus hypocapnia. The present study compared CVR in 31 cognitively unimpaired older adults (ages 55-87) and 30 healthy younger adults (ages 18-28). Breath control tasks induced CVR to hypocapnia (0.1 Hz paced breathing) and hypercapnia (15s breath holds) during pseudo-continuous arterial spin labeling MRI. Relative to younger adults, cognitively unimpaired older adults displayed lower levels of global CVR under both hypocapnia and hypercapnia. In region-of-interest analyses, older adults exhibited attenuated CVR to hypocapnia in select frontal and temporal regions, and lower CVR to hypercapnia in all cortical, limbic, and subcortical regions examined, relative to younger adults. Results indicate age-related deficits in CVR are detectible even in cognitively unimpaired older adults and are disproportionately related to vasodilatory (hypercapnia) responses relative to vasoconstrictive (hypocapnia) responses. Findings may offer means for early detection of cerebrovascular dysfunction.
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Affiliation(s)
- Belinda Yew
- Department of Psychology, University of Southern California, Los Angeles, CA, USA
| | - Jung Yun Jang
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA, USA
| | - Shubir Dutt
- Department of Psychology, University of Southern California, Los Angeles, CA, USA
| | - Yanrong Li
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA, USA
| | - Isabel J Sible
- Department of Psychology, University of Southern California, Los Angeles, CA, USA
| | - Aimée Gaubert
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA, USA
| | - Jean K Ho
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA, USA
| | - Anna E Blanken
- Department of Psychology, University of Southern California, Los Angeles, CA, USA
| | - Anisa Marshall
- Department of Psychology, University of Southern California, Los Angeles, CA, USA
| | - Xingfeng Shao
- Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, CA, USA
| | - Danny J J Wang
- Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, CA, USA
| | - Daniel A Nation
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA, USA; Department of Psychological Science, University of California, Irvine, Irvine, CA, USA.
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21
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Zhong XZ, Chen JJ. Resting-state functional magnetic resonance imaging signal variations in aging: The role of neural activity. Hum Brain Mapp 2022; 43:2880-2897. [PMID: 35293656 PMCID: PMC9120570 DOI: 10.1002/hbm.25823] [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: 10/04/2021] [Revised: 01/20/2022] [Accepted: 02/23/2022] [Indexed: 11/23/2022] Open
Abstract
Resting‐state functional magnetic resonance imaging (rs‐fMRI) has been extensively used to study brain aging, but the age effect on the frequency content of the rs‐fMRI signal has scarcely been examined. Moreover, the neuronal implications of such age effects and age–sex interaction remain unclear. In this study, we examined the effects of age and sex on the rs‐fMRI signal frequency using the Leipzig mind–brain–body data set. Over a frequency band of up to 0.3 Hz, we found that the rs‐fMRI fluctuation frequency is higher in the older adults, although the fluctuation amplitude is lower. The rs‐fMRI signal frequency is also higher in men than in women. Both age and sex effects on fMRI frequency vary with the frequency band examined but are not found in the frequency of physiological‐noise components. This higher rs‐fMRI frequency in older adults is not mediated by the electroencephalograph (EEG)‐frequency increase but a likely link between fMRI signal frequency and EEG entropy, which vary with age and sex. Additionally, in different rs‐fMRI frequency bands, the fMRI‐EEG amplitude ratio is higher in young adults. This is the first study to investigate the neuronal contribution to age and sex effects in the frequency dimension of the rs‐fMRI signal and may lead to the development of new, frequency‐based rs‐fMRI metrics. Our study demonstrates that Fourier analysis of the fMRI signal can reveal novel information about aging. Furthermore, fMRI and EEG signals reflect different aspects of age‐ and sex‐related brain differences, but the signal frequency and complexity, instead of amplitude, may hold their link.
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Affiliation(s)
- Xiaole Z Zhong
- Rotman Research Institute, Baycrest Health Sciences, Toronto, Ontario, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - J Jean Chen
- Rotman Research Institute, Baycrest Health Sciences, Toronto, Ontario, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.,Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
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22
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Sayin ES, Davidian A, Levine H, Venkatraghavan L, Mikulis DJ, Fisher JA, Sobczyk O, Duffin J. Does breathing pattern affect cerebrovascular reactivity? Exp Physiol 2021; 107:183-191. [PMID: 34961983 DOI: 10.1113/ep090122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 12/22/2021] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Is cerebrovascular reactivity affected by isocapnic changes in breathing pattern? What is the main finding and its importance? The main finding is that cerebrovascular reactivity does not change with isocapnic variations in tidal volume and frequency. ABSTRACT Deviations of arterial carbon dioxide tension from resting values affect cerebral blood vessel tone and thereby cerebral blood flow. Arterial carbon dioxide tension also affects central respiratory chemoreceptors, adjusting respiratory drive. This coincidence raises the question whether respiratory drive also affects the cerebral blood flow response to carbon dioxide. A change in cerebral blood flow for a given change in the arterial carbon dioxide tension is defined as cerebrovascular reactivity. Two studies have reached conflicting conclusions on this question, using voluntary control of breathing as a disturbing factor during measurements of cerebrovascular reactivity. Here we address some of the methodological limitations of both studies by using sequential gas delivery and targeted control of carbon dioxide and oxygen to enable a separation of the effects of carbon dioxide on cerebrovascular reactivity from breathing vigor. We confirm there is no detectable superimposed effect of breathing efforts on cerebrovascular reactivity. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Ece Su Sayin
- Department of Anaesthesia and Pain Management, University Health Network, Toronto, Canada.,Department of Physiology, University of Toronto, Toronto, Canada
| | - Anahis Davidian
- Department of Physiology, University of Toronto, Toronto, Canada
| | - Harrison Levine
- Department of Anaesthesia and Pain Management, University Health Network, Toronto, Canada.,Department of Physiology, University of Toronto, Toronto, Canada
| | - Lashmi Venkatraghavan
- Department of Anaesthesia and Pain Management, University Health Network, Toronto, Canada.,Department of Physiology, University of Toronto, Toronto, Canada
| | - David J Mikulis
- Institute of Medical Sciences, University of Toronto, Toronto, Canada.,Joint Department of Medical Imaging and the Functional Neuroimaging Laboratory, University Health Network, Toronto, Canada
| | - Joseph A Fisher
- Department of Anaesthesia and Pain Management, University Health Network, Toronto, Canada.,Department of Physiology, University of Toronto, Toronto, Canada.,Institute of Medical Sciences, University of Toronto, Toronto, Canada
| | - Olivia Sobczyk
- Department of Anaesthesia and Pain Management, University Health Network, Toronto, Canada.,Joint Department of Medical Imaging and the Functional Neuroimaging Laboratory, University Health Network, Toronto, Canada
| | - James Duffin
- Department of Anaesthesia and Pain Management, University Health Network, Toronto, Canada.,Department of Physiology, University of Toronto, Toronto, Canada
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23
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Batson C, Gomez A, Sainbhi AS, Froese L, Zeiler FA. Association of Age and Sex With Multi-Modal Cerebral Physiology in Adult Moderate/Severe Traumatic Brain Injury: A Narrative Overview and Future Avenues for Personalized Approaches. Front Pharmacol 2021; 12:676154. [PMID: 34899283 PMCID: PMC8652202 DOI: 10.3389/fphar.2021.676154] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 10/22/2021] [Indexed: 12/30/2022] Open
Abstract
The impact of age and biological sex on outcome in moderate/severe traumatic brain injury (TBI) has been documented in large cohort studies, with advanced age and male sex linked to worse long-term outcomes. However, the association between age/biological sex and high-frequency continuous multi-modal monitoring (MMM) cerebral physiology is unclear, with only sparing reference made in guidelines and major literature in moderate/severe TBI. In this narrative review, we summarize some of the largest studies associating various high-frequency MMM parameters with age and biological sex in moderate/severe TBI. To start, we present this by highlighting the representative available literature on high-frequency data from Intracranial Pressure (ICP), Cerebral Perfusion Pressure (CPP), Extracellular Brain Tissue Oxygenation (PbtO2), Regional Cerebral Oxygen Saturations (rSO2), Cerebral Blood Flow (CBF), Cerebral Blood Flow Velocity (CBFV), Cerebrovascular Reactivity (CVR), Cerebral Compensatory Reserve, common Cerebral Microdialysis (CMD) Analytes and their correlation to age and sex in moderate/severe TBI cohorts. Then we present current knowledge gaps in the literature, discuss biological implications of age and sex on cerebrovascular monitoring in TBI and some future avenues for bedside research into the cerebrovascular physiome after TBI.
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Affiliation(s)
- C Batson
- Department of Human Anatomy and Cell Science, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - A Gomez
- Department of Human Anatomy and Cell Science, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada.,Section of Neurosurgery, Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - A S Sainbhi
- Biomedical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, MB, Canada
| | - L Froese
- Biomedical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, MB, Canada
| | - F A Zeiler
- Department of Human Anatomy and Cell Science, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada.,Section of Neurosurgery, Department of Surgery, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada.,Biomedical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, MB, Canada.,Centre on Aging, University of Manitoba, Winnipeg, MB, Canada.,Division of Anaesthesia, Department of Medicine, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
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24
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Wang R, Poublanc J, Crawley AP, Sobczyk O, Kneepkens S, Mcketton L, Tator C, Wu R, Mikulis DJ. Cerebrovascular reactivity changes in acute concussion: a controlled cohort study. Quant Imaging Med Surg 2021; 11:4530-4542. [PMID: 34737921 DOI: 10.21037/qims-20-1296] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 06/18/2021] [Indexed: 11/06/2022]
Abstract
Background Evidence suggests that cerebrovascular reactivity (CVR) increases within the first week after the incidence of concussion, indicating a disruption of normal autoregulation. We sought to extend these findings by investigating the effects of acute concussion on the speed of CVR response and by visualizing global and regional impairments in individual patients with acute concussion. Methods Twelve patients aged 18-40 years who experienced concussion less than a week before this prospective study were included. Twelve age and sex-matched healthy subjects constituted the control group. In all subjects, CVR was assessed using blood oxygenation level-dependent (BOLD) echo-planar imaging with a 3.0T MRI scanner, in combination with changes in end-tidal partial pressure of CO2 (PETCO2). In each subject, we calculated the CVR amplitude and CVR response time in the gray and white matter using a step and ramp PETCO2 challenge. In addition, a separate group of 39 healthy controls who underwent the same evaluation was used to create atlases with voxel-wise mean and standard deviation of CVR amplitude and CVR response time. This allowed us to convert each metric of the 12 patients with concussion and the 12 healthy controls into z-score maps. These maps were then used to generate and compare z-scores for each of the two groups. Group differences were calculated using an unpaired t-test. Results All studies were well tolerated without any serious adverse events. Anatomical MRI was normal in all study subjects. No differences in CO2 stimulus and O2 targeting were observed between the two participant groups during BOLD MRI. With regard to the gray matter, the CVR magnitude step (P=0.117) and ramp + 10 (P=0.085) were not significantly different between patients with concussion and healthy controls. However, the tau value was significantly lower in patients with concussion than in the healthy controls (P=0.04). With regard to the white matter, the CVR magnitude step (P=0.003) and ramp + 10 (P=0.031) were significantly higher and the tau value (P=0.024) was significantly shorter in patients with concussion than in healthy controls. After z-score transformation, the z tau value was significantly lower in patients with concussion than in healthy controls (Grey matter P=0.021, White matter P=0.003). Comparison of the three parameters, z ramp + 10, z step, and z tau, between the two groups showed that z step (Grey matter P=0.035, White matter P=0.005) was the most sensitive parameter and that z ramp + 10 (Grey matter P=0.073, White matter P=0.126) was the least sensitive parameter. Conclusions Concussion is associated with patient-specific abnormalities in BOLD cerebrovascular responsiveness that occur in the setting of normal global CVR. This study demonstrates that the measurement of CVR using BOLD MRI and precise CO2 control is a safe, reliable, reproducible, and clinically useful method for evaluating the state of patients with concussion. It has the potential to be an important tool for assessing the severity and duration of symptoms after concussion.
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Affiliation(s)
- Runrun Wang
- Joint Department of Medical Imaging, University Health Network, The Toronto Western Hospital, The University of Toronto, Toronto, Ontario, Canada.,Department of Neurology, Henan Provincial People's Hospital, Zhengzhou University People's Hospital, Henan, China.,Department of Medical Imaging, the Second Affiliated Hospital, Medical College of Shantou University, Shantou, China
| | - Julien Poublanc
- Joint Department of Medical Imaging, University Health Network, The Toronto Western Hospital, The University of Toronto, Toronto, Ontario, Canada
| | - Adrian P Crawley
- Joint Department of Medical Imaging, University Health Network, The Toronto Western Hospital, The University of Toronto, Toronto, Ontario, Canada
| | - Olivia Sobczyk
- Joint Department of Medical Imaging, University Health Network, The Toronto Western Hospital, The University of Toronto, Toronto, Ontario, Canada
| | - Sander Kneepkens
- Joint Department of Medical Imaging, University Health Network, The Toronto Western Hospital, The University of Toronto, Toronto, Ontario, Canada
| | - Larissa Mcketton
- Joint Department of Medical Imaging, University Health Network, The Toronto Western Hospital, The University of Toronto, Toronto, Ontario, Canada
| | - Charles Tator
- Department of Surgery, Division of Neurosurgery, University Health Network, The Toronto Western Hospital, The University of Toronto, Toronto, Ontario, Canada
| | - Renhua Wu
- Department of Medical Imaging, the Second Affiliated Hospital, Medical College of Shantou University, Shantou, China
| | - David J Mikulis
- Joint Department of Medical Imaging, University Health Network, The Toronto Western Hospital, The University of Toronto, Toronto, Ontario, Canada
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25
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Yao JF, Yang HCS, Wang JH, Liang Z, Talavage TM, Tamer GG, Jang I, Tong Y. A novel method of quantifying hemodynamic delays to improve hemodynamic response, and CVR estimates in CO2 challenge fMRI. J Cereb Blood Flow Metab 2021; 41:1886-1898. [PMID: 33444087 PMCID: PMC8327112 DOI: 10.1177/0271678x20978582] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Elevated carbon dioxide (CO2) in breathing air is widely used as a vasoactive stimulus to assess cerebrovascular functions under hypercapnia (i.e., "stress test" for the brain). Blood-oxygen-level-dependent (BOLD) is a contrast mechanism used in functional magnetic resonance imaging (fMRI). BOLD is used to study CO2-induced cerebrovascular reactivity (CVR), which is defined as the voxel-wise percentage BOLD signal change per mmHg change in the arterial partial pressure of CO2 (PaCO2). Besides the CVR, two additional important parameters reflecting the cerebrovascular functions are the arrival time of arterial CO2 at each voxel, and the waveform of the local BOLD signal. In this study, we developed a novel analytical method to accurately calculate the arrival time of elevated CO2 at each voxel using the systemic low frequency oscillations (sLFO: 0.01-0.1 Hz) extracted from the CO2 challenge data. In addition, 26 candidate hemodynamic response functions (HRF) were used to quantitatively describe the temporal brain reactions to a CO2 stimulus. We demonstrated that our approach improved the traditional method by allowing us to accurately map three perfusion-related parameters: the relative arrival time of blood, the hemodynamic response function, and CVR during a CO2 challenge.
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Affiliation(s)
- Jinxia Fiona Yao
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Ho-Ching Shawn Yang
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - James H Wang
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Zhenhu Liang
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA.,School of Electrical Engineering, Yanshan University, Qinhuangdao, China
| | - Thomas M Talavage
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA.,School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, USA
| | - Gregory G Tamer
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Ikbeom Jang
- School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, USA
| | - Yunjie Tong
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
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26
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Perioperative Care of Patients at High Risk for Stroke During or After Non-cardiac, Non-neurological Surgery: 2020 Guidelines From the Society for Neuroscience in Anesthesiology and Critical Care. J Neurosurg Anesthesiol 2021; 32:210-226. [PMID: 32433102 DOI: 10.1097/ana.0000000000000686] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Perioperative stroke is associated with considerable morbidity and mortality. Stroke recognition and diagnosis are challenging perioperatively, and surgical patients receive therapeutic interventions less frequently compared with stroke patients in the outpatient setting. These updated guidelines from the Society for Neuroscience in Anesthesiology and Critical Care provide evidence-based recommendations regarding perioperative care of patients at high risk for stroke. Recommended areas for future investigation are also proposed.
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27
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Sobczyk O, Fierstra J, Venkatraghavan L, Poublanc J, Duffin J, Fisher JA, Mikulis DJ. Measuring Cerebrovascular Reactivity: Sixteen Avoidable Pitfalls. Front Physiol 2021; 12:665049. [PMID: 34305634 PMCID: PMC8294324 DOI: 10.3389/fphys.2021.665049] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Accepted: 06/07/2021] [Indexed: 12/04/2022] Open
Abstract
An increase in arterial PCO2 is the most common stressor used to increase cerebral blood flow for assessing cerebral vascular reactivity (CVR). That CO2 is readily obtained, inexpensive, easy to administer, and safe to inhale belies the difficulties in extracting scientifically and clinically relevant information from the resulting flow responses. Over the past two decades, we have studied more than 2,000 individuals, most with cervical and cerebral vascular pathology using CO2 as the vasoactive agent and blood oxygen-level-dependent magnetic resonance imaging signal as the flow surrogate. The ability to deliver different forms of precise hypercapnic stimuli enabled systematic exploration of the blood flow-related signal changes. We learned the effect on CVR of particular aspects of the stimulus such as the arterial partial pressure of oxygen, the baseline PCO2, and the magnitude, rate, and pattern of its change. Similarly, we learned to interpret aspects of the flow response such as its magnitude, and the speed and direction of change. Finally, we were able to test whether the response falls into a normal range. Here, we present a review of our accumulated insight as 16 “lessons learned.” We hope many of these insights are sufficiently general to apply to a range of types of CO2-based vasoactive stimuli and perfusion metrics used for CVR.
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Affiliation(s)
- 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 Laboratory, University Health Network, Toronto, ON, Canada
| | - Jorn Fierstra
- Department of Neurosurgery, University Hospital Zurich, Zürich, Switzerland
| | - Lakshmikumar Venkatraghavan
- 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 Laboratory, University Health Network, Toronto, ON, Canada
| | - James Duffin
- Department of Anaesthesia and Pain Management, University Health Network, University of Toronto, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Joseph A Fisher
- Department of Anaesthesia and Pain Management, University Health Network, University of Toronto, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - David J Mikulis
- Joint Department of Medical Imaging and the Functional Neuroimaging Laboratory, University Health Network, Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Toronto, ON, Canada
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28
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Poublanc J, Shafi R, Sobczyk O, Sam K, Mandell DM, Venkatraghavan L, Duffin J, Fisher JA, Mikulis DJ. Normal BOLD Response to a Step CO 2 Stimulus After Correction for Partial Volume Averaging. Front Physiol 2021; 12:639360. [PMID: 34194335 PMCID: PMC8236700 DOI: 10.3389/fphys.2021.639360] [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: 12/08/2020] [Accepted: 04/26/2021] [Indexed: 11/26/2022] Open
Abstract
Cerebrovascular reactivity (CVR) is defined as the change in cerebral blood flow induced by a change in a vasoactive stimulus. CVR using BOLD MRI in combination with changes in end-tidal CO2 is a very useful method for assessing vascular performance. In recent years, this technique has benefited from an advanced gas delivery method where end-tidal CO2 can be targeted, measured very precisely, and validated against arterial blood gas sampling (Ito et al., 2008). This has enabled more precise comparison of an individual patient against a normative atlas of healthy subjects. However, expected control ranges for CVR metrics have not been reported in the literature. In this work, we calculate and report the range of control values for the magnitude (mCVR), the steady state amplitude (ssCVR), and the speed (TAU) of the BOLD response to a standard step stimulus, as well as the time delay (TD) as observed in a cohort of 45 healthy controls. These CVR metrics maps were corrected for partial volume averaging for brain tissue types using a linear regression method to enable more accurate quantitation of CVR metrics. In brief, this method uses adjacent voxel CVR metrics in combination with their tissue composition to write the corresponding set of linear equations for estimating CVR metrics of gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF). After partial volume correction, mCVR and ssCVR increase as expected in gray matter, respectively, by 25 and 19%, and decrease as expected in white matter by 33 and 13%. In contrast, TAU and TD decrease in gray matter by 33 and 13%. TAU increase in white matter by 24%, but TD surprisingly decreased by 9%. This correction enables more accurate voxel-wise tissue composition providing greater precision when reporting gray and white matter CVR values.
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Affiliation(s)
- Julien Poublanc
- Joint Department of Medical Imaging and the Functional Neuroimaging Laboratory, University Health Network, Toronto, ON, Canada
| | - Reema Shafi
- Joint Department of Medical Imaging and the Functional Neuroimaging Laboratory, University Health Network, Toronto, ON, Canada
| | - Olivia Sobczyk
- Joint Department of Medical Imaging and the Functional Neuroimaging Laboratory, University Health Network, Toronto, ON, Canada.,Department of Anesthesia and Pain Management, University Health Network, Toronto, ON, Canada
| | - Kevin Sam
- Department of Radiology and Radiological Sciences, Johns Hopkins University, United States
| | - Daniel M Mandell
- Joint Department of Medical Imaging and the Functional Neuroimaging Laboratory, University Health Network, Toronto, ON, Canada
| | | | - James Duffin
- Department of Anesthesia and Pain Management, University Health Network, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Joseph A Fisher
- Department of Anesthesia and Pain Management, University Health Network, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - David J Mikulis
- Joint Department of Medical Imaging and the Functional Neuroimaging Laboratory, University Health Network, Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Toronto, ON, Canada
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29
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Differential regional cerebral blood flow reactivity to alterations in end-tidal gases in healthy volunteers. Can J Anaesth 2021; 68:1497-1506. [PMID: 34105067 DOI: 10.1007/s12630-021-02042-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 04/05/2021] [Accepted: 04/09/2021] [Indexed: 12/19/2022] Open
Abstract
PURPOSE Anesthesia is associated with alterations in end-tidal (ET) respiratory gases from the awake state. These alterations result in marked vasoactive changes in regional cerebral blood flow (rCBF). Altered regional cerebrovascular reactivity (rCVR) is linked to neurologic dysfunction. We examined these differences in reactivity from prior work by focusing on the ratio of vasoconstriction with hyperoxia/hypocapnia (HO/hc):vasodilation with hypercapnia (HC) using magnetic resonance imaging pseudo-continuous arterial spin labelling (pCASL) to measure rCBF and compare rCVR The distribution and magnitude of these ratios could provide insights into rCBF during clinical anesthesia and inform future research into the origins of postoperative delirium (POD). METHODS Ten healthy subjects underwent cerebral blood flow (CBF) studies using pCASL with computer-controlled delivery of ET gases to assess flow effects of hyperoxia, hypercapnia, and hyperoxia/hypocapnia as part of a larger study into cerebrovascular reactivity. The vasoconstrictor stimulus was compared with the vasodilator stimulus by the ratio HO/hc:HC. RESULTS Hyperoxia minimally decreased whole brain CBF by - 0.6%/100 mm Hg increase in ETO2. Hypercapnia increased CBF by +4.6%/mm Hg carbon dioxide (CO2) and with HO/hc CBF decreased by - 5.1%/mm Hg CO2. The brain exhibited markedly different rCVR-regional HO/hc:HC ratios varied from 7.2:1 (greater response to vasoconstriction) to 0.49:1 (greater response to vasodilation). Many of the ratios greater than 1, where vasoconstriction predominated, were seen in regions associated with memory, cognition, and executive function, including the entorhinal cortex, hippocampus, parahippocampus, and dorsolateral prefrontal cortex. CONCLUSIONS In awake humans, marked rCBF changes occurred with alterations in ET respiratory gases common under anesthesia. Such heterogeneous reactivity may be relevant to future studies to identify those at risk of POD.
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30
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Kim D, Hughes TM, Lipford ME, Craft S, Baker LD, Lockhart SN, Whitlow CT, Okonmah-Obazee SE, Hugenschmidt CE, Bobinski M, Jung Y. Relationship Between Cerebrovascular Reactivity and Cognition Among People With Risk of Cognitive Decline. Front Physiol 2021; 12:645342. [PMID: 34135768 PMCID: PMC8201407 DOI: 10.3389/fphys.2021.645342] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 04/29/2021] [Indexed: 11/13/2022] Open
Abstract
Vascular risk factors (e.g., obesity and hypertension) are associated with cerebral small vessel disease, Alzheimer's disease (AD) pathology, and dementia. Reduced perfusion may reflect the impaired ability of blood vessels to regulate blood flow in reaction to varying circumstances such as hypercapnia (increased end-tidal partial pressures of CO2). It has been shown that cerebrovascular reactivity (CVR) measured with blood-oxygen-level-dependent (BOLD) MRI is correlated with cognitive performance and alterations of CVR may be an indicator of vascular disfunction leading to cognitive decline. However, the underlying mechanism of CVR alterations in BOLD signal may not be straight-forward because BOLD signal is affected by multiple physiological parameters, such as cerebral blood flow (CBF), cerebral blood volume, and oxygen metabolism. Arterial spin labeling (ASL) MRI quantitatively measures blood flow in the brain providing images of local CBF. Therefore, in this study, we measured CBF and its changes using a dynamic ASL technique during a hypercapnia challenge and tested if CBF or CVR was related to cognitive performance using the Mini-mental state examination (MMSE) score. Seventy-eight participants underwent cognitive testing and MRI including ASL during a hypercapnia challenge with a RespirAct computer-controlled gas blender, targeting 10 mmHg higher end-tidal CO2 level than the baseline while end-tidal O2 level was maintained. Pseudo-continuous ASL (PCASL) was collected during a 2-min baseline and a 2-min hypercapnic period. CVR was obtained by calculating a percent change of CBF per the end-tidal CO2 elevation in mmHg between the baseline and the hypercapnic challenge. Multivariate regression analyses demonstrated that baseline resting CBF has no significant relationship with MMSE, while lower CVR in the whole brain gray matter (β = 0.689, p = 0.005) and white matter (β = 0.578, p = 0.016) are related to lower MMSE score. In addition, region of interest (ROI) based analysis showed positive relationships between MMSE score and CVR in 26 out of 122 gray matter ROIs.
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Affiliation(s)
- Donghoon Kim
- Department of Biomedical Engineering, University of California, Davis, Davis, CA, United States.,Department of Radiology, University of California, Davis, Davis, CA, United States
| | - Timothy M Hughes
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - Megan E Lipford
- Department of Radiology, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - Suzanne Craft
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - Laura D Baker
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - Samuel N Lockhart
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - Christopher T Whitlow
- Department of Radiology, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | | | - Christina E Hugenschmidt
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC, United States
| | - Matthew Bobinski
- Department of Radiology, University of California, Davis, Davis, CA, United States
| | - Youngkyoo Jung
- Department of Biomedical Engineering, University of California, Davis, Davis, CA, United States.,Department of Radiology, University of California, Davis, Davis, CA, United States.,Department of Radiology, Wake Forest School of Medicine, Winston-Salem, NC, United States
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31
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Sobczyk O, Sayin ES, Sam K, Poublanc J, Duffin J, Fisher JA, Mikulis DJ. The Reproducibility of Cerebrovascular Reactivity Across MRI Scanners. Front Physiol 2021; 12:668662. [PMID: 34025455 PMCID: PMC8134667 DOI: 10.3389/fphys.2021.668662] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 04/12/2021] [Indexed: 11/13/2022] Open
Abstract
Cerebrovascular reactivity (CVR) is defined as the ratio of the cerebral blood flow (CBF) response to an increase in a vasoactive stimulus. We used changes in blood oxygenation level-dependent (BOLD) MRI as surrogates for changes of CBF, and standardized quantitative changes in arterial partial pressure of carbon dioxide as the stimulus. Despite uniform stimulus and test conditions, differences in voxel-wise BOLD changes between testing sites may remain, attributable to physiologic and machine variability. We generated a reference atlas of normal CVR metrics (voxel-wise mean and SD) for each of two sites. We hypothesized that there would be no significant differences in CVR between the two atlases enabling each atlas to be used at any site. A total of 69 healthy subjects were tested to create site-specific atlases, with 20 of those individuals tested at both sites. 38 subjects were scanned at Site 1 (17F, 37.5 ± 16.8 y) and 51 subjects were tested at Site 2 (22F, 40.9 ± 17.4 y). MRI platforms were: Site 1, 3T Magnetom Skyra Siemens scanner with 20-channel head and neck coil; and Site 2, 3T HDx Signa GE scanner with 8-channel head coil. To construct the atlases, test results of individual subjects were co-registered into a standard space and voxel-wise mean and SD CVR metrics were calculated. Map comparisons of z scores found no significant differences between white matter or gray matter in the 20 subjects scanned at both sites when analyzed with either atlas. We conclude that individual CVR testing, and atlas generation are compatible across sites provided that standardized respiratory stimuli and BOLD MRI scan parameters are used. This enables the use of a single atlas to score the normality of CVR metrics across multiple sites.
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Affiliation(s)
- Olivia Sobczyk
- Joint Department of Medical Imaging and the Functional Neuroimaging Laboratory, University Health Network, Toronto, ON, Canada.,Department of Anaesthesia and Pain Management, University Health Network, Toronto, ON, Canada
| | - Ece Su Sayin
- Department of Anaesthesia and Pain Management, University Health Network, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Kevin Sam
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Julien Poublanc
- Joint Department of Medical Imaging and the Functional Neuroimaging Laboratory, University Health Network, Toronto, ON, Canada
| | - James Duffin
- Department of Anaesthesia and Pain Management, University Health Network, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Joseph A Fisher
- Department of Anaesthesia and Pain Management, University Health Network, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada.,Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
| | - David J Mikulis
- Joint Department of Medical Imaging and the Functional Neuroimaging Laboratory, University Health Network, Toronto, ON, Canada.,Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
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32
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Milej D, Abdalmalak A, Rajaram A, Jhajj A, Owen AM, St. Lawrence K. Incorporating early and late-arriving photons to improve the reconstruction of cerebral hemodynamic responses acquired by time-resolved near-infrared spectroscopy. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:056003. [PMCID: PMC8130006 DOI: 10.1117/1.jbo.26.5.056003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 04/28/2021] [Indexed: 06/14/2023]
Abstract
Significance: Despite its advantages in terms of safety, low cost, and portability, functional near-infrared spectroscopy applications can be challenging due to substantial signal contamination from hemodynamics in the extracerebral layer (ECL). Time-resolved near-infrared spectroscopy (tr NIRS) can improve sensitivity to brain activity but contamination from the ECL remains an issue. This study demonstrates how brain signal isolation can be further improved by applying regression analysis to tr data acquired at a single source–detector distance. Aim: To investigate if regression analysis can be applied to single-channel trNIRS data to further isolate the brain and reduce signal contamination from the ECL. Approach: Appropriate regressors for trNIRS were selected based on simulations, and performance was evaluated by applying the regression technique to oxygenation responses recording during hypercapnia and functional activation. Results: Compared to current methods of enhancing depth sensitivity for trNIRS (i.e., higher statistical moments and late gates), incorporating regression analysis using a signal sensitive to the ECL significantly improved the extraction of cerebral oxygenation signals. In addition, this study demonstrated that regression could be applied to trNIRS data from a single detector using the early arriving photons to capture hemodynamic changes in the ECL. Conclusion: Applying regression analysis to trNIRS metrics with different depth sensitivities improves the characterization of cerebral oxygenation signals.
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Affiliation(s)
- Daniel Milej
- Lawson Health Research Institute, Imaging Program, London, Ontario, Canada
- Western University, Department of Medical Biophysics, London, Ontario, Canada
| | - Androu Abdalmalak
- Lawson Health Research Institute, Imaging Program, London, Ontario, Canada
- Western University, Department of Medical Biophysics, London, Ontario, Canada
| | - Ajay Rajaram
- Lawson Health Research Institute, Imaging Program, London, Ontario, Canada
- Western University, Department of Medical Biophysics, London, Ontario, Canada
| | - Amandeep Jhajj
- Western University, Department of Medical Biophysics, London, Ontario, Canada
| | - Adrian M. Owen
- Western University, Brain and Mind Institute, London, Ontario, Canada
| | - Keith St. Lawrence
- Lawson Health Research Institute, Imaging Program, London, Ontario, Canada
- Western University, Department of Medical Biophysics, London, Ontario, Canada
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33
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Sleight E, Stringer MS, Marshall I, Wardlaw JM, Thrippleton MJ. Cerebrovascular Reactivity Measurement Using Magnetic Resonance Imaging: A Systematic Review. Front Physiol 2021; 12:643468. [PMID: 33716793 PMCID: PMC7947694 DOI: 10.3389/fphys.2021.643468] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 02/01/2021] [Indexed: 12/27/2022] Open
Abstract
Cerebrovascular reactivity (CVR) magnetic resonance imaging (MRI) probes cerebral haemodynamic changes in response to a vasodilatory stimulus. CVR closely relates to the health of the vasculature and is therefore a key parameter for studying cerebrovascular diseases such as stroke, small vessel disease and dementias. MRI allows in vivo measurement of CVR but several different methods have been presented in the literature, differing in pulse sequence, hardware requirements, stimulus and image processing technique. We systematically reviewed publications measuring CVR using MRI up to June 2020, identifying 235 relevant papers. We summarised the acquisition methods, experimental parameters, hardware and CVR quantification approaches used, clinical populations investigated, and corresponding summary CVR measures. CVR was investigated in many pathologies such as steno-occlusive diseases, dementia and small vessel disease and is generally lower in patients than in healthy controls. Blood oxygen level dependent (BOLD) acquisitions with fixed inspired CO2 gas or end-tidal CO2 forcing stimulus are the most commonly used methods. General linear modelling of the MRI signal with end-tidal CO2 as the regressor is the most frequently used method to compute CVR. Our survey of CVR measurement approaches and applications will help researchers to identify good practice and provide objective information to inform the development of future consensus recommendations.
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Affiliation(s)
- Emilie Sleight
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom,UK Dementia Research Institute, Edinburgh, United Kingdom
| | - Michael S. Stringer
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom,UK Dementia Research Institute, Edinburgh, United Kingdom,*Correspondence: Michael S. Stringer
| | - Ian Marshall
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom,UK Dementia Research Institute, Edinburgh, United Kingdom
| | - Joanna M. Wardlaw
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom,UK Dementia Research Institute, Edinburgh, United Kingdom
| | - Michael J. Thrippleton
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom,UK Dementia Research Institute, Edinburgh, United Kingdom
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34
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Anderson VC, Tagge IJ, Li X, Quinn JF, Kaye JA, Bourdette DN, Spain RI, Riccelli LP, Sammi MK, Springer CS, Rooney WD. Observation of Reduced Homeostatic Metabolic Activity and/or Coupling in White Matter Aging. J Neuroimaging 2020; 30:658-665. [PMID: 32558031 PMCID: PMC7529981 DOI: 10.1111/jon.12744] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 06/01/2020] [Accepted: 06/02/2020] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND AND PURPOSE Transvascular water exchange plays a key role in the functional integrity of the blood-brain barrier (BBB). In white matter (WM), a variety of imaging modalities have demonstrated age-related changes in structure and metabolism, but the extent to which water exchange is altered remains unclear. Here, we investigated the cumulative effects of healthy aging on WM capillary water exchange. METHODS A total of 38 healthy adults (aged 36-80 years) were studied using 7T dynamic contrast enhanced MRI. Blood volume fraction (vb ) and capillary water efflux rate constant (kpo ) were determined by fitting changes in the 1 H2 O longitudinal relaxation rate constant (R1 ) during contrast agent bolus passage to a two-compartment exchange model. WM volume was determined by morphometric analysis of structural images. RESULTS R1 values and WM volume showed similar trajectories of age-related decline. Among all subjects, vb and kpo averaged 1.7 (±0.5) mL/100 g of tissue and 2.1 (±1.1) s-1 , respectively. While vb showed minimal changes over the 40-year-age span of participants, kpo declined 0.06 s-1 (ca. 3%) per year (r = -.66; P < .0005), from near 4 s-1 at age 30 to ca. 2 s-1 at age 70. The association remained significant after controlling for WM volume. CONCLUSIONS Previous studies have shown that kpo tracks Na+ , K+ -ATPase activity-dependent water exchange at the BBB and likely reflects neurogliovascular unit (NGVU) coupled metabolic activity. The age-related decline in kpo observed here is consistent with compromised NGVU metabolism in older individuals and the dysregulated cellular bioenergetics that accompany normal brain aging.
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Affiliation(s)
- Valerie C Anderson
- Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR
| | - Ian J Tagge
- Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR
| | - Xin Li
- Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR
| | - Joseph F Quinn
- Department of Neurology, Oregon Health & Science University, Portland, OR
| | - Jeffrey A Kaye
- Department of Neurology, Oregon Health & Science University, Portland, OR
| | - Dennis N Bourdette
- Department of Neurology, Oregon Health & Science University, Portland, OR
| | - Rebecca I Spain
- Department of Neurology, Oregon Health & Science University, Portland, OR
| | - Louis P Riccelli
- Diagnostic Radiology, Oregon Health & Science University, Portland, OR
| | - Manoj K Sammi
- Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR
| | - Charles S Springer
- Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR
| | - William D Rooney
- Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR
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35
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Milej D, Shahid M, Abdalmalak A, Rajaram A, Diop M, St. Lawrence K. Characterizing dynamic cerebral vascular reactivity using a hybrid system combining time-resolved near-infrared and diffuse correlation spectroscopy. BIOMEDICAL OPTICS EXPRESS 2020; 11:4571-4585. [PMID: 32923065 PMCID: PMC7449704 DOI: 10.1364/boe.392113] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 04/28/2020] [Accepted: 05/12/2020] [Indexed: 05/09/2023]
Abstract
This study presents the characterization of dynamic cerebrovascular reactivity (CVR) in healthy adults by a hybrid optical system combining time-resolved (TR) near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS). Blood flow and oxygenation (oxy- and deoxy-hemoglobin) responses to a step hypercapnic challenge were recorded to characterize dynamic and static components of CVR. Data were acquired at short and long source-detector separations (r SD) to assess the impact of scalp hemodynamics, and moment analysis applied to the TR-NIRS to further enhance the sensitivity to the brain. Comparing blood flow and oxygenation responses acquired at short and long r SD demonstrated that scalp contamination distorted the CVR time courses, particularly for oxyhemoglobin. This effect was significantly diminished by the greater depth sensitivity of TR NIRS and less evident in the DCS data due to the higher blood flow in the brain compared to the scalp. The reactivity speed was similar for blood flow and oxygenation in the healthy brain. Given the ease-of-use, portability, and non-invasiveness of this hybrid approach, it is well suited to investigate if the temporal relationship between CBF and oxygenation is altered by factors such as age and cerebrovascular disease.
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Affiliation(s)
- Daniel Milej
- Imaging Program, Lawson Health Research Institute, London, Ontario, N6A 4V2, Canada
- Department of Medical Biophysics, Western University, London, Ontario, N6A 5C1, Canada
| | - Marwan Shahid
- Imaging Program, Lawson Health Research Institute, London, Ontario, N6A 4V2, Canada
- Department of Medical Biophysics, Western University, London, Ontario, N6A 5C1, Canada
| | - Androu Abdalmalak
- Imaging Program, Lawson Health Research Institute, London, Ontario, N6A 4V2, Canada
- Department of Medical Biophysics, Western University, London, Ontario, N6A 5C1, Canada
| | - Ajay Rajaram
- Imaging Program, Lawson Health Research Institute, London, Ontario, N6A 4V2, Canada
- Department of Medical Biophysics, Western University, London, Ontario, N6A 5C1, Canada
| | - Mamadou Diop
- Imaging Program, Lawson Health Research Institute, London, Ontario, N6A 4V2, Canada
- Department of Medical Biophysics, Western University, London, Ontario, N6A 5C1, Canada
| | - Keith St. Lawrence
- Imaging Program, Lawson Health Research Institute, London, Ontario, N6A 4V2, Canada
- Department of Medical Biophysics, Western University, London, Ontario, N6A 5C1, Canada
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36
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Intzandt B, Sabra D, Foster C, Desjardins-Crépeau L, Hoge RD, Steele CJ, Bherer L, Gauthier CJ. Higher cardiovascular fitness level is associated with lower cerebrovascular reactivity and perfusion in healthy older adults. J Cereb Blood Flow Metab 2020; 40:1468-1481. [PMID: 31342831 PMCID: PMC7308519 DOI: 10.1177/0271678x19862873] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Aging is accompanied by vascular and structural changes in the brain, which include decreased grey matter volume (GMV), cerebral blood flow (CBF), and cerebrovascular reactivity (CVR). Enhanced fitness in aging has been related to preservation of GMV and CBF, and in some cases CVR, although there are contradictory relationships reported between CVR and fitness. To gain a better understanding of the complex interplay between fitness and GMV, CBF and CVR, the present study assessed these factors concurrently. Data from 50 participants, aged 55 to 72, were used to derive GMV, CBF, CVR and VO2peak. Results revealed that lower CVR was associated with higher VO2peak throughout large areas of the cerebral cortex. Within these regions lower fitness was associated with higher CBF and a faster hemodynamic response to hypercapnia. Overall, our results indicate that the relationships between age, fitness, cerebral health and cerebral hemodynamics are complex, likely involving changes in chemosensitivity and autoregulation in addition to changes in arterial stiffness. Future studies should collect other physiological outcomes in parallel with quantitative imaging, such as measures of chemosensitivity and autoregulation, to further understand the intricate effects of fitness on the aging brain, and how this may bias quantitative measures of cerebral health.
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Affiliation(s)
- Brittany Intzandt
- INDI Department, Concordia University, Montreal, Canada.,PERFORM Centre, Concordia University, Montreal, Canada.,Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal, Montreal, Canada
| | - Dalia Sabra
- Départment de Médecine, Université de Montréal, Canada
| | - Catherine Foster
- PERFORM Centre, Concordia University, Montreal, Canada.,Physics Department, Concordia University, Montreal, Canada
| | - Laurence Desjardins-Crépeau
- Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal, Montreal, Canada.,Centre de Recherche de l'Institut de Cardiologie de Montréal, Montréal, Canada
| | - Richard D Hoge
- Department of Neurology and Neurosurgery, McGill University, Canada
| | - Christopher J Steele
- Department of Psychology, Concordia University, Montreal, Canada.,Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Louis Bherer
- PERFORM Centre, Concordia University, Montreal, Canada.,Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal, Montreal, Canada.,Départment de Médecine, Université de Montréal, Canada.,Centre de Recherche de l'Institut de Cardiologie de Montréal, Montréal, Canada
| | - Claudine J Gauthier
- PERFORM Centre, Concordia University, Montreal, Canada.,Physics Department, Concordia University, Montreal, Canada.,Centre de Recherche de l'Institut de Cardiologie de Montréal, Montréal, Canada
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37
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Gertel VH, Karimi H, Dennis NA, Neely KA, Diaz MT. Lexical frequency affects functional activation and accuracy in picture naming among older and younger adults. Psychol Aging 2020; 35:536-552. [PMID: 32191059 DOI: 10.1037/pag0000454] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
As individuals age, they experience increased difficulties producing speech, especially with infrequent words. Older adults report that word retrieval difficulties frequently occur and are highly frustrating. However, little is known about how age affects the neural basis of language production. Moreover, age-related increases in brain activation are often observed, yet there is disagreement about whether such increases represent a form of neural compensation or dedifferentiation. We used functional magnetic resonance imaging (fMRI) to determine if there are age-related differences in functional activation during picture naming and whether such differences are consistent with a compensatory, dedifferentiation, or hybrid account that factors in difficulty. Healthy younger and older adults performed a picture-naming task with stimuli that varied in lexical frequency-our proxy for difficulty. Both younger and older adults were sensitive to lexical frequency behaviorally and neurally. However, younger adults performed more accurately overall and engaged both language (bilateral insula and temporal pole) and cognitive control (bilateral superior frontal gyri and left cingulate) regions to a greater extent than older adults when processing lower frequency items. In both groups, poorer performance was associated with increases in functional activation consistent with dedifferentiation. Moreover, there were age-related differences in the strength of these correlations, with better performing younger adults modulating the bilateral insula and temporal pole and better performing older adults modulating bilateral frontal pole and precuneus. Overall, these findings highlight the influence of task difficulty on fMRI activation in older adults and suggest that as task difficulty increases, older and younger adults rely on different neural resources. (PsycInfo Database Record (c) 2020 APA, all rights reserved).
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38
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The association between BOLD-based cerebrovascular reactivity (CVR) and end-tidal CO 2 in healthy subjects. Neuroimage 2019; 207:116365. [PMID: 31734432 PMCID: PMC8080082 DOI: 10.1016/j.neuroimage.2019.116365] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 10/25/2019] [Accepted: 11/13/2019] [Indexed: 01/22/2023] Open
Abstract
Cerebrovascular reactivity (CVR) mapping using CO2-inhalation can provide important insight into vascular health. At present, blood-oxygenation-level-dependent (BOLD) MRI acquisition is the most commonly used CVR method due to its high sensitivity, high spatial resolution, and relatively straightforward processing. However, large variations in CVR across subjects and across different sessions of the same subject are often observed, which can cloud the ability of this promising measure in detecting diseases or monitoring treatment responses. The present work aims to identify the physiological components underlying the observed variability in CVR data. When studying the association between CVR value and the subject’s CO2 levels in a total of N = 253 healthy participants, we found that CVR was lower in individuals with a higher basal end-tidal CO2, EtCO2 (slope = −0.0036 ± 0.0008%/mmHg2, p < 0.001), or with a greater EtCO2 change (ΔEtCO2) with hypercapnic condition (slope = −0.0072 ± 0.0018%/mmHg2, p < 0.001). In a within-subject setting, when studying the CVR difference between two repeated scans (with repositioning) in relation to the corresponding differences in basal EtCO2 and ΔEtCO2 (n = 11), it was found that CVR values were lower if the basal EtCO2 or ΔEtCO2 during that particular scan session was greater. The present work suggests that basal physiological state and the level of hypercapnic stimulus intensity should be considered in application studies of CVR in order to reduce inter-subject and intra-subject variations in the data. Potential approaches to use these findings to reduce noise and augment sensitivity are proposed.
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He Y, Gu M, Zhang H, Deng J, Wu X, Guo Y. Effect of insomnia after acute ischemic stroke on cerebrovascular reactivity: a prospective clinical study in China. Sleep Med 2019; 63:82-87. [DOI: 10.1016/j.sleep.2019.07.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 06/28/2019] [Accepted: 07/04/2019] [Indexed: 11/16/2022]
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Determining differences between critical closing pressure and resistance-area product: responses of the healthy young and old to hypocapnia. Pflugers Arch 2019; 471:1117-1126. [DOI: 10.1007/s00424-019-02290-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 05/31/2019] [Accepted: 06/05/2019] [Indexed: 10/26/2022]
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Hoiland RL, Fisher JA, Ainslie PN. Regulation of the Cerebral Circulation by Arterial Carbon Dioxide. Compr Physiol 2019; 9:1101-1154. [DOI: 10.1002/cphy.c180021] [Citation(s) in RCA: 101] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Guedes RCA, Abadie-Guedes R. Brain Aging and Electrophysiological Signaling: Revisiting the Spreading Depression Model. Front Aging Neurosci 2019; 11:136. [PMID: 31231207 PMCID: PMC6567796 DOI: 10.3389/fnagi.2019.00136] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 05/21/2019] [Indexed: 12/31/2022] Open
Abstract
As a consequence of worldwide improvement in health care, the aging portion of the human population has increased, now representing a higher proportion of the total population. This fact raises great concern regarding how to age while maintaining good brain function. Very often, alterations in brain electrophysiological signaling are associated with age-dependent functional disorders of the brain. Therefore, animal models suitable for the study of age-related changes in electrical activity of the brain can be very useful. Herein, we review changes in brain electrophysiological features as a function of age by analyzing studies in the rat brain on the phenomenon known as cortical spreading depression (CSD). Alterations in the brain’s capability to generate and propagate CSD may be related to differences in the propensity to develop certain neurological diseases, such as epilepsy, stroke, and migraine, which can biunivocally interact with the aging process. In this review, we revisit ours and others’ previous studies on electrophysiological features of the CSD phenomenon, such as its velocity of propagation and amplitude and duration of its slow negative DC shift, as a function of the animal age, as well as the interaction between age and other factors, such as ethanol consumption, physical exercise, and nutritional status. In addition, we discuss one relatively new feature through which CSD modulates brain signaling: the ability to potentiate the brain’s spontaneous electrical activity. We conclude that the CSD model might importantly contribute to a better understanding of the aging/brain signaling relationship.
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Affiliation(s)
| | - Ricardo Abadie-Guedes
- Departamento de Fisiologia e Farmacologia, Universidade Federal de Pernambuco, Recife, Brazil
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McKetton L, Cohn M, Tang-Wai DF, Sobczyk O, Duffin J, Holmes KR, Poublanc J, Sam K, Crawley AP, Venkatraghavan L, Fisher JA, Mikulis DJ. Cerebrovascular Resistance in Healthy Aging and Mild Cognitive Impairment. Front Aging Neurosci 2019; 11:79. [PMID: 31031616 PMCID: PMC6474328 DOI: 10.3389/fnagi.2019.00079] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 03/19/2019] [Indexed: 12/04/2022] Open
Abstract
Measures of cerebrovascular reactivity (CVR) are used to judge the health of the brain vasculature. In this study, we report the use of several different analyses of blood oxygen dependent (BOLD) fMRI responses to CO2 to provide a number of metrics of CVR based on the sigmoidal resistance response to CO2. To assess possible differences in these metrics with age, we compiled atlases reflecting voxel-wise means and standard deviations for four different age ranges and for a group of patients with mild cognitive impairment (MCI) and compared them. Sixty-seven subjects were recruited for this study and scanned at 3T field strength. Of those, 51 healthy control volunteers between the ages of 18–83 were recruited, and 16 (MCI) subjects between the ages of 61–83 were recruited. Testing was carried out using an automated computer-controlled gas blender to induce hypercapnia in a step and ramp paradigm while monitoring end-tidal partial pressures of CO2. Surprisingly, some resistance sigmoid parameters in the oldest control group were increased compared to the youngest control group. Resistance amplitude maps showed increases in clusters within the temporal cortex, thalamus, corpus callosum and brainstem, and resistance reserve maps showed increases in clusters within the cingulate cortex, frontal gyrus, and corpus callosum. These findings suggest that some aspects of vascular reactivity in parts of the brain are initially maintained with age but then may increase in later years. We found significant reductions in all resistance sigmoid parameters (amplitude, reserve, sensitivity, midpoint, and range) when comparing MCI patients to controls. Additionally, in controls and in MCI patients, amplitude, range, reserve, and sensitivity in white matter (WM) was significantly reduced compared to gray matter (GM). WM midpoints were significantly above those of GM. Our general conclusion is that vascular regulation in terms of cerebral blood flow (CBF) responsiveness to CO2 is not significantly affected by age, but is reduced in MCI. These changes in cerebrovascular regulation demonstrate the value of resistance metrics for mapping areas of dysregulated blood flow in individuals with MCI. They may also be of value in the investigation of patients with vascular risk factors at risk for developing vascular dementia.
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Affiliation(s)
- Larissa McKetton
- Joint Department of Medical Imaging, University Health Network (UHN), Toronto, ON, Canada
| | - Melanie Cohn
- Krembil Brain Institute, University Health Network (UHN), Toronto, ON, Canada.,Department of Psychology, University of Toronto, Toronto, ON, Canada
| | - David F Tang-Wai
- Krembil Brain Institute, University Health Network (UHN), Toronto, ON, Canada.,Department of Medicine, Division of Neurology, University of Toronto and the University Health Network Memory Clinic, Toronto, ON, Canada
| | - Olivia Sobczyk
- Joint Department of Medical Imaging, University Health Network (UHN), Toronto, ON, Canada
| | - James Duffin
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Kenneth R Holmes
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Julien Poublanc
- Joint Department of Medical Imaging, University Health Network (UHN), Toronto, ON, Canada
| | - Kevin Sam
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Adrian P Crawley
- Joint Department of Medical Imaging, University Health Network (UHN), Toronto, ON, Canada
| | - Lashmi Venkatraghavan
- Department of Anaesthesia and Pain Management, University Health Network (UHN), Toronto, ON, Canada
| | - Joseph A Fisher
- Joint Department of Medical Imaging, University Health Network (UHN), Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Toronto, ON, Canada.,Department of Anaesthesia and Pain Management, University Health Network (UHN), Toronto, ON, Canada
| | - David J Mikulis
- Joint Department of Medical Imaging, University Health Network (UHN), Toronto, ON, Canada.,Krembil Brain Institute, University Health Network (UHN), Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Toronto, ON, Canada
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