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Aghilinejad A, Gharib M. Assessing pressure wave components for aortic stiffness monitoring through spectral regression learning. EUROPEAN HEART JOURNAL OPEN 2024; 4:oeae040. [PMID: 38863521 PMCID: PMC11165314 DOI: 10.1093/ehjopen/oeae040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 05/02/2024] [Accepted: 05/10/2024] [Indexed: 06/13/2024]
Abstract
Aims The ageing process notably induces structural changes in the arterial system, primarily manifesting as increased aortic stiffness, a precursor to cardiovascular events. While wave separation analysis is a robust tool for decomposing the components of blood pressure waveform, its relationship with cardiovascular events, such as aortic stiffening, is incompletely understood. Furthermore, its applicability has been limited due to the need for concurrent measurements of pressure and flow. Our aim in this study addresses this gap by introducing a spectral regression learning method for pressure-only wave separation analysis. Methods and results Leveraging data from the Framingham Heart Study (2640 individuals, 55% women), we evaluate the accuracy of pressure-only estimates, their interchangeability with a reference method based on ultrasound-derived flow waves, and their association with carotid-femoral pulse wave velocity (PWV). Method-derived estimates are strongly correlated with the reference ones for forward wave amplitude ( R 2 = 0.91 ), backward wave amplitude ( R 2 = 0.88 ), and reflection index ( R 2 = 0.87 ) and moderately correlated with a time delay between forward and backward waves ( R 2 = 0.38 ). The proposed pressure-only method shows interchangeability with the reference method through covariate analysis. Adjusting for age, sex, body size, mean blood pressure, and heart rate, the results suggest that both pressure-only and pressure-flow evaluations of wave separation parameters yield similar model performances for predicting carotid-femoral PWV, with forward wave amplitude being the only significant factor (P < 0.001; 95% confidence interval, 0.056-0.097). Conclusion We propose an interchangeable pressure-only wave separation analysis method and demonstrate its clinical applicability in capturing aortic stiffening. The proposed method provides a valuable non-invasive tool for assessing cardiovascular health.
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Affiliation(s)
- Arian Aghilinejad
- Division of Engineering and Applied Science, California Institute of Technology, 1200 E California Blvd, Pasadena, CA 91125, USA
| | - Morteza Gharib
- Division of Engineering and Applied Science, California Institute of Technology, 1200 E California Blvd, Pasadena, CA 91125, USA
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Aghilinejad A, Amlani F, Mazandarani SP, King KS, Pahlevan NM. Mechanistic insights on age-related changes in heart-aorta-brain hemodynamic coupling using a pulse wave model of the entire circulatory system. Am J Physiol Heart Circ Physiol 2023; 325:H1193-H1209. [PMID: 37712923 PMCID: PMC10908406 DOI: 10.1152/ajpheart.00314.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 08/14/2023] [Accepted: 08/31/2023] [Indexed: 09/16/2023]
Abstract
Age-related changes in aortic biomechanics can impact the brain by reducing blood flow and increasing pulsatile energy transmission. Clinical studies have shown that impaired cardiac function in patients with heart failure is associated with cognitive impairment. Although previous studies have attempted to elucidate the complex relationship between age-associated aortic stiffening and pulsatility transmission to the cerebral network, they have not adequately addressed the effect of interactions between aortic stiffness and left ventricle (LV) contractility (neither on energy transmission nor on brain perfusion). In this study, we use a well-established and validated one-dimensional blood flow and pulse wave computational model of the circulatory system to address how age-related changes in cardiac function and vasculature affect the underlying mechanisms involved in the LV-aorta-brain hemodynamic coupling. Our results reveal how LV contractility affects pulsatile energy transmission to the brain, even with preserved cardiac output. Our model demonstrates the existence of an optimal heart rate (near the normal human heart rate) that minimizes pulsatile energy transmission to the brain at different contractility levels. Our findings further suggest that the reduction in cerebral blood flow at low levels of LV contractility is more prominent in the setting of age-related aortic stiffening. Maintaining optimal blood flow to the brain requires either an increase in contractility or an increase in heart rate. The former consistently leads to higher pulsatile power transmission, and the latter can either increase or decrease subsequent pulsatile power transmission to the brain.NEW & NOTEWORTHY We investigated the impact of major aging mechanisms of the arterial system and cardiac function on brain hemodynamics. Our findings suggest that aging has a significant impact on heart-aorta-brain coupling through changes in both arterial stiffening and left ventricle (LV) contractility. Understanding the underlying physical mechanisms involved here can potentially be a key step for developing more effective therapeutic strategies that can mitigate the contributions of abnormal LV-arterial coupling toward neurodegenerative diseases and dementia.
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Affiliation(s)
- Arian Aghilinejad
- Department of Aerospace and Mechanical Engineering, University of Southern California, Los Angeles, California, United States
| | - Faisal Amlani
- Laboratoire de Mécanique Paris-Saclay, Université Paris-Saclay, Paris, France
| | - Sohrab P Mazandarani
- Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, United States
| | - Kevin S King
- Barrow Neurological Institute, Phoenix, Arizona, United States
| | - Niema M Pahlevan
- Department of Aerospace and Mechanical Engineering, University of Southern California, Los Angeles, California, United States
- Division of Cardiovascular Medicine, Department of Medicine, University of Southern California, Los Angeles, California, United States
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Shah P, Doyle E, Wood JC, Borzage MT. Imputation models and error analysis for phase contrast MR cerebral blood flow measurements. Front Physiol 2023; 14:1096297. [PMID: 36891147 PMCID: PMC9988286 DOI: 10.3389/fphys.2023.1096297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 01/24/2023] [Indexed: 02/22/2023] Open
Abstract
Cerebral blood flow (CBF) supports brain metabolism. Diseases impair CBF, and pharmacological agents modulate CBF. Many techniques measure CBF, but phase contrast (PC) MR imaging through the four arteries supplying the brain is rapid and robust. However, technician error, patient motion, or tortuous vessels degrade quality of the measurements of the internal carotid (ICA) or vertebral (VA) arteries. We hypothesized that total CBF could be imputed from measurements in subsets of these 4 feeding vessels without excessive penalties in accuracy. We analyzed PC MR imaging from 129 patients, artificially excluded 1 or more vessels to simulate degraded imaging quality, and developed models of imputation for the missing data. Our models performed well when at least one ICA was measured, and resulted in R 2 values of 0.998-0.990, normalized root mean squared error values of 0.044-0.105, and intra-class correlation coefficient of 0.982-0.935. Thus, these models were comparable or superior to the test-retest variability in CBF measured by PC MR imaging. Our imputation models allow retrospective correction for corrupted blood vessel measurements when measuring CBF and guide prospective CBF acquisitions.
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Affiliation(s)
- Payal Shah
- Division of Cardiology, Department of Pediatrics, Children's Hospital Los Angeles, Los Angeles, CA, United States
| | - Eamon Doyle
- Department of Radiology, Children's Hospital Los Angeles, Los Angeles, CA, United States
| | - John C Wood
- Division of Cardiology, Department of Pediatrics, Children's Hospital Los Angeles, Los Angeles, CA, United States
| | - Matthew T Borzage
- Division of Neonatology, Department of Pediatrics, Children's Hospital Los Angeles, Keck School of Medicine, Fetal and Neonatal Institute, University of Southern California, Los Angeles, CA, United States
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Soldan A, Alfini A, Pettigrew C, Faria A, Hou X, Lim C, Lu H, Spira AP, Zipunnikov V, Albert M. Actigraphy-estimated physical activity is associated with functional and structural brain connectivity among older adults. Neurobiol Aging 2022; 116:32-40. [PMID: 35551019 PMCID: PMC10167793 DOI: 10.1016/j.neurobiolaging.2022.04.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 02/04/2022] [Accepted: 04/09/2022] [Indexed: 12/20/2022]
Abstract
Higher physical activity levels are associated with reduced cognitive decline among older adults; however, current understanding of underlying brain mechanisms is limited. This cross-sectional study investigated the relationship between actigraphy-estimated total volume of physical activity (TVPA) and magnetic resonance imaging (MRI) measures of white matter hyperintensities (WMH), and functional and structural brain connectivity, measured by resting-state functional MRI and diffusion tensor imaging. Study participants (N = 156, mean age = 71 years) included 136 with normal cognition and 20 with Mild Cognitive Impairment. Higher TVPA was associated with greater functional connectivity within the default-mode network and greater network modularity (a measure of network specialization), as well as with greater anisotropy and lower radial diffusion in white matter, suggesting better structural connectivity. These associations with functional and structural connectivity were independent of one another and independent of the level of vascular risk, APOE-ε4 status, cognitive reserve, and WMH volume, which were not associated with TVPA. Findings suggest that physical activity is beneficial for brain connectivity among older individuals with varying levels of risk for cognitive decline.
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Affiliation(s)
- Anja Soldan
- Division of Cognitive Neuroscience, Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Alfonso Alfini
- National Center on Sleep Disorders Research, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD, USA
| | - Corinne Pettigrew
- Division of Cognitive Neuroscience, Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Andreia Faria
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Xirui Hou
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Chantelle Lim
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Hanzhang Lu
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Adam P Spira
- Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA; Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Vadim Zipunnikov
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Marilyn Albert
- Division of Cognitive Neuroscience, Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Manquat E, Ravaux H, Kindermans M, Joachim J, Serrano J, Touchard C, Mateo J, Mebazaa A, Gayat E, Vallée F, Cartailler J. Impact of impaired cerebral blood flow autoregulation on electroencephalogram signals in adults undergoing propofol anaesthesia: a pilot study. BJA OPEN 2022; 1:100004. [PMID: 37588691 PMCID: PMC10430849 DOI: 10.1016/j.bjao.2022.100004] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 01/26/2022] [Indexed: 08/18/2023]
Abstract
Background Cerebral autoregulation actively maintains cerebral blood flow over a range of MAPs. During general anaesthesia, this mechanism may not compensate for reductions in MAP leading to brain hypoperfusion. Cerebral autoregulation can be assessed using the mean flow index derived from Doppler measurements of average blood velocity in the middle cerebral artery, but this is impractical for routine monitoring within the operating room. Here, we investigate the possibility of using the EEG as a proxy measure for a loss of cerebral autoregulation, determined by the mean flow index. Methods Thirty-six patients (57.5 [44.25; 66.5] yr; 38.9% women, non-emergency neuroradiology surgery) anaesthetised using propofol were prospectively studied. Continuous recordings of MAP, average blood velocity in the middle cerebral artery, EEG, and regional cerebral oxygen saturation were made. Poor cerebral autoregulation was defined as a mean flow index greater than 0.3. Results Eighteen patients had preserved cerebral autoregulation, and 18 had altered cerebral autoregulation. The two groups had similar ages, MAPs, and average blood velocities in the middle cerebral artery. Patients with altered cerebral autoregulation exhibited a significantly slower alpha peak frequency (9.4 [9.0, 9.9] Hz vs 10.5 [10.1, 10.9] Hz, P<0.001), which persisted after adjusting for age, norepinephrine infusion rate, and ASA class (odds ratio=0.038 [confidence interval, 0.004, 0.409]; P=0.007). Conclusion In this pilot study, we found that loss of cerebral autoregulation was associated with a slower alpha peak frequency, independent of age. This work suggests that impaired cerebral autoregulation could be monitored in the operating room using the existing EEG setup. Clinical trial registration NCT03769142.
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Affiliation(s)
- Elsa Manquat
- Department of Anesthesiology, Burn and Critical Care, St-Louis-Lariboisiere University Hospital, Assistance Publique Hôpitaux de Paris, Paris, France
- AP-HP-Inria, Laboratoire Daniel Bernoulli, Paris, France
| | - Hugues Ravaux
- Department of Anesthesiology, Burn and Critical Care, St-Louis-Lariboisiere University Hospital, Assistance Publique Hôpitaux de Paris, Paris, France
| | - Manuel Kindermans
- Department of Anesthesiology, Burn and Critical Care, St-Louis-Lariboisiere University Hospital, Assistance Publique Hôpitaux de Paris, Paris, France
| | - Jona Joachim
- Department of Anesthesiology, Burn and Critical Care, St-Louis-Lariboisiere University Hospital, Assistance Publique Hôpitaux de Paris, Paris, France
| | - José Serrano
- Department of Anesthesiology, Burn and Critical Care, St-Louis-Lariboisiere University Hospital, Assistance Publique Hôpitaux de Paris, Paris, France
| | - Cyril Touchard
- Department of Anesthesiology, Burn and Critical Care, St-Louis-Lariboisiere University Hospital, Assistance Publique Hôpitaux de Paris, Paris, France
| | - Joaquim Mateo
- Department of Anesthesiology, Burn and Critical Care, St-Louis-Lariboisiere University Hospital, Assistance Publique Hôpitaux de Paris, Paris, France
| | - Alexandre Mebazaa
- Department of Anesthesiology, Burn and Critical Care, St-Louis-Lariboisiere University Hospital, Assistance Publique Hôpitaux de Paris, Paris, France
- INSERM, UMR-942, Paris, France
| | - Etienne Gayat
- Department of Anesthesiology, Burn and Critical Care, St-Louis-Lariboisiere University Hospital, Assistance Publique Hôpitaux de Paris, Paris, France
- INSERM, UMR-942, Paris, France
| | - Fabrice Vallée
- Department of Anesthesiology, Burn and Critical Care, St-Louis-Lariboisiere University Hospital, Assistance Publique Hôpitaux de Paris, Paris, France
- Laboratoire de Mécanique des Solides (LMS), Ecole Polytechnique/CNRS/Institut Polytechnique de Paris, France
- INSERM, UMR-942, Paris, France
| | - Jérôme Cartailler
- Department of Anesthesiology, Burn and Critical Care, St-Louis-Lariboisiere University Hospital, Assistance Publique Hôpitaux de Paris, Paris, France
- INSERM, UMR-942, Paris, France
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King KS, Vintimilla RM, Braskie MN, Wei K, Hall JR, Borzage M, Johnson LA, Yaffe K, Toga AW, O'Bryant SE. Vascular risk profile and white matter hyperintensity volume among Mexican Americans and non-Hispanic Whites: The HABLE study. ALZHEIMER'S & DEMENTIA (AMSTERDAM, NETHERLANDS) 2022; 14:e12263. [PMID: 35229016 PMCID: PMC8865739 DOI: 10.1002/dad2.12263] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 07/12/2021] [Accepted: 08/03/2021] [Indexed: 01/18/2023]
Abstract
INTRODUCTION Among vascular risk factors we hypothesized that an increased prevalence of diabetes in Hispanics would be associated with greater white matter hyperintensity (WMH) volume, which may contribute to cognitive decline. METHODS A total of 1318 participants (60% female; 49% Hispanic, 51% non-Hispanic White; age 66.2 ± 8.9 years) underwent clinical evaluation and brain magnetic resonance imaging (MRI). WMH volume associations were assessed with age, sex, and ethnicity and then with vascular risk factors in a selective regression model. RESULTS WMH volume was greater with older age (P < .0001), Hispanic ethnicity (P = .02), and female sex (P = .049). WMH volume was best predicted by age, diastolic blood pressure, hypertension history, hemoglobin A1c (HbA1c), white blood cell count, and hematocrit (P < .01 for all). Elevated HbA1c was associated with greater WMH volume among Hispanics (parameter estimate 0.08 ± 0.02, P < .0001) but not non-Hispanic Whites (parameter estimate 0.02 ± 0.04, P = .5). DISCUSSION WMH volume was greater in Hispanics, which may be partly explained by increased WMH volume related to elevated HbA1c among Hispanics but not non-Hispanic Whites.
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Affiliation(s)
- Kevin S. King
- Department of NeuroradiologyBarrow Neurological InstitutePhoenixArizonaUSA
| | - Raul M Vintimilla
- Institute for Translational ResearchUniversity of North Texas Health Science CenterFort WorthTexasUSA,Department of Pharmacology and NeuroscienceUniversity of North Texas Health Science CenterFort WorthTexasUSA
| | - Meredith N Braskie
- Imaging Genetics CenterKeck School of MedicineUSCStevens Neuroimaging and Informatics InstituteLos AngelesCaliforniaUSA
| | - Ke Wei
- Department of Computer ScienceUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
| | - James R Hall
- Institute for Translational ResearchUniversity of North Texas Health Science CenterFort WorthTexasUSA,Department of Pharmacology and NeuroscienceUniversity of North Texas Health Science CenterFort WorthTexasUSA
| | - Matt Borzage
- Research PediatricsChildren's Hospital of Los AngelesKeck School of MedicineUSCLos AngelesCaliforniaUSA
| | - Leigh A Johnson
- Institute for Translational ResearchUniversity of North Texas Health Science CenterFort WorthTexasUSA,Department of Pharmacology and NeuroscienceUniversity of North Texas Health Science CenterFort WorthTexasUSA
| | - Kristine Yaffe
- Department of Psychiatry, Neurology, and Epidemology and BiostatisticsUniversity of CaliforniaSan FranciscoCaliforniaUSA,San Francisco VA Medical CenterSan FranciscoCaliforniaUSA
| | - Arthur W Toga
- Laboratory of Neuro ImagingUSC Stevens Neuroimaging and Informatics InstituteKeck School of Medicine of USCUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
| | - Sid E O'Bryant
- Institute for Translational ResearchUniversity of North Texas Health Science CenterFort WorthTexasUSA,Department of Pharmacology and NeuroscienceUniversity of North Texas Health Science CenterFort WorthTexasUSA
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Soldan A, Pettigrew C, Zhu Y, Wang MC, Bilgel M, Hou X, Lu H, Miller MI, Albert M. Association of Lifestyle Activities with Functional Brain Connectivity and Relationship to Cognitive Decline among Older Adults. Cereb Cortex 2021; 31:5637-5651. [PMID: 34184058 DOI: 10.1093/cercor/bhab187] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 06/02/2021] [Accepted: 06/03/2021] [Indexed: 01/05/2023] Open
Abstract
This study examines the relationship of engagement in different lifestyle activities to connectivity in large-scale functional brain networks, and whether network connectivity modifies cognitive decline, independent of brain amyloid levels. Participants (N = 153, mean age = 69 years, including N = 126 with amyloid imaging) were cognitively normal when they completed resting-state functional magnetic resonance imaging, a lifestyle activity questionnaire, and cognitive testing. They were followed with annual cognitive tests up to 5 years (mean = 3.3 years). Linear regressions showed positive relationships between cognitive activity engagement and connectivity within the dorsal attention network, and between physical activity levels and connectivity within the default-mode, limbic, and frontoparietal control networks, and global within-network connectivity. Additionally, higher cognitive and physical activity levels were independently associated with higher network modularity, a measure of functional network specialization. These associations were largely independent of APOE4 genotype, amyloid burden, global brain atrophy, vascular risk, and level of cognitive reserve. Moreover, higher connectivity in the dorsal attention, default-mode, and limbic networks, and greater global connectivity and modularity were associated with reduced cognitive decline, independent of APOE4 genotype and amyloid burden. These findings suggest that changes in functional brain connectivity may be one mechanism by which lifestyle activity engagement reduces cognitive decline.
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Affiliation(s)
- Anja Soldan
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Corinne Pettigrew
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Yuxin Zhu
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21287, USA
| | - Mei-Cheng Wang
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21287, USA
| | - Murat Bilgel
- Laboratory of Behavioral Neuroscience, Intramural Research Program, National Institute on Aging, Baltimore, MD 21224, USA
| | - Xirui Hou
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Hanzhang Lu
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Michael I Miller
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Marilyn Albert
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Hou X, Liu P, Gu H, Chan M, Li Y, Peng SL, Wig G, Yang Y, Park D, Lu H. Estimation of brain functional connectivity from hypercapnia BOLD MRI data: Validation in a lifespan cohort of 170 subjects. Neuroimage 2018; 186:455-463. [PMID: 30463025 DOI: 10.1016/j.neuroimage.2018.11.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 10/31/2018] [Accepted: 11/16/2018] [Indexed: 01/07/2023] Open
Abstract
Functional connectivity MRI, based on Blood-Oxygenation-Level-Dependent (BOLD) signals, is typically performed while the subject is at rest. On the other hand, BOLD is also widely used in physiological imaging such as cerebrovascular reactivity (CVR) mapping using hypercapnia (HC) as a modulator. We therefore hypothesize that hypercapnia BOLD data can be used to extract FC metrics after factoring out the effects of the physiological modulation, which will allow simultaneous assessment of neural and vascular function and may be particularly important in populations such as aging and cerebrovascular diseases. The present work aims to systematically examine the feasibility of hypercapnia BOLD-based FC mapping using three commonly applied analysis methods, specifically dual-regression Independent Component Analysis (ICA), region-based FC matrix analysis, and graph-theory based network analysis, in a large cohort of 170 healthy subjects ranging from 20 to 88 years old. To validate the hypercapnia BOLD results, we also compared these FC metrics with those obtained from conventional resting-state data. ICA analysis of the hypercapnia BOLD data revealed FC maps that strongly resembled those reported in the literature. FC matrix using region-based analysis showed a correlation of 0.97 on the group-level and 0.54 ± 0.10 on the individual-level, when comparing between hypercapnia and resting-state results. Although the correspondence on the individual-level was moderate, this was primarily attributed to variations intrinsic to FC mapping, because a corresponding resting-vs-resting comparison in a sub-cohort (N = 39) revealed a similar correlation of 0.57 ± 0.09. Graph-theory computations were also feasible in hypercapnia BOLD data and indices of global efficiency, clustering coefficient, modularity, and segregation were successfully derived. Hypercapnia FC results revealed age-dependent differences in which within-network connections generally exhibited an age-dependent decrease while between-network connections showed an age-dependent increase.
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Affiliation(s)
- Xirui Hou
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Peiying Liu
- The Russell H. Morgan Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Hong Gu
- Neuroimaging Research Branch, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, USA
| | - Micaela Chan
- Center for Vital Longevity, School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, TX, USA
| | - Yang Li
- The Russell H. Morgan Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Graduate School of Biomedical Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Shin-Lei Peng
- The Russell H. Morgan Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung, Taiwan
| | - Gagan Wig
- Center for Vital Longevity, School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, TX, USA; Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Yihong Yang
- Neuroimaging Research Branch, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, USA
| | - Denise Park
- Center for Vital Longevity, School of Behavioral and Brain Sciences, University of Texas at Dallas, Dallas, TX, USA; Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Hanzhang Lu
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA; The Russell H. Morgan Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA.
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