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Hu Y, Zhang F, Ikonomovic M, Yang T. The Role of NRF2 in Cerebrovascular Protection: Implications for Vascular Cognitive Impairment and Dementia (VCID). Int J Mol Sci 2024; 25:3833. [PMID: 38612642 PMCID: PMC11012233 DOI: 10.3390/ijms25073833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 03/20/2024] [Accepted: 03/22/2024] [Indexed: 04/14/2024] Open
Abstract
Vascular cognitive impairment and dementia (VCID) represents a broad spectrum of cognitive decline secondary to cerebral vascular aging and injury. It is the second most common type of dementia, and the prevalence continues to increase. Nuclear factor erythroid 2-related factor 2 (NRF2) is enriched in the cerebral vasculature and has diverse roles in metabolic balance, mitochondrial stabilization, redox balance, and anti-inflammation. In this review, we first briefly introduce cerebrovascular aging in VCID and the NRF2 pathway. We then extensively discuss the effects of NRF2 activation in cerebrovascular components such as endothelial cells, vascular smooth muscle cells, pericytes, and perivascular macrophages. Finally, we summarize the clinical potential of NRF2 activators in VCID.
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Affiliation(s)
- Yizhou Hu
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15216, USA; (Y.H.); (F.Z.); (M.I.)
- Pittsburgh Institute of Brain Disorders and Recovery, University of Pittsburgh, Pittsburgh, PA 15216, USA
- Department of Internal Medicine, University of Pittsburgh Medical Center (UPMC) McKeesport, McKeesport, PA 15132, USA
| | - Feng Zhang
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15216, USA; (Y.H.); (F.Z.); (M.I.)
- Pittsburgh Institute of Brain Disorders and Recovery, University of Pittsburgh, Pittsburgh, PA 15216, USA
| | - Milos Ikonomovic
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15216, USA; (Y.H.); (F.Z.); (M.I.)
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15216, USA
- Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, Pittsburgh, PA 15240, USA
| | - Tuo Yang
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15216, USA; (Y.H.); (F.Z.); (M.I.)
- Pittsburgh Institute of Brain Disorders and Recovery, University of Pittsburgh, Pittsburgh, PA 15216, USA
- Department of Internal Medicine, University of Pittsburgh Medical Center (UPMC), Pittsburgh, PA 15216, USA
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2
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Daher A, Payne S. The conducted vascular response as a mediator of hypercapnic cerebrovascular reactivity: A modelling study. Comput Biol Med 2024; 170:107985. [PMID: 38245966 DOI: 10.1016/j.compbiomed.2024.107985] [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: 11/08/2023] [Revised: 12/29/2023] [Accepted: 01/13/2024] [Indexed: 01/23/2024]
Abstract
It is well established that the cerebral blood flow (CBF) shows exquisite sensitivity to changes in the arterial blood partial pressure of CO2 ( [Formula: see text] ), which is reflected by an index termed cerebrovascular reactivity. In response to elevations in [Formula: see text] (hypercapnia), the vessels of the cerebral microvasculature dilate, thereby decreasing the vascular resistance and increasing CBF. Due to the challenges of access, scale and complexity encountered when studying the microvasculature, however, the mechanisms behind cerebrovascular reactivity are not fully understood. Experiments have previously established that the cholinergic release of the Acetylcholine (ACh) neurotransmitter in the cortex is a prerequisite for the hypercapnic response. It is also known that ACh functions as an endothelial-dependent agonist, in which the local administration of ACh elicits local hyperpolarization in the vascular wall; this hyperpolarization signal is then propagated upstream the vascular network through the endothelial layer and is coupled to a vasodilatory response in the vascular smooth muscle (VSM) layer in what is known as the conducted vascular response (CVR). Finally, experimental data indicate that the hypercapnic response is more strongly correlated with the CO2 levels in the tissue than in the arterioles. Accordingly, we hypothesize that the CVR, evoked by increases in local tissue CO2 levels and a subsequent local release of ACh, is responsible for the CBF increase observed in response to elevations in [Formula: see text] . By constructing physiologically grounded dynamic models of CBF and control in the cerebral vasculature, ones that integrate the available knowledge and experimental data, we build a new model of the series of signalling events and pathways underpinning the hypercapnic response, and use the model to provide compelling evidence that corroborates the aforementioned hypothesis. If the CVR indeed acts as a mediator of the hypercapnic response, the proposed mechanism would provide an important addition to our understanding of the repertoire of metabolic feedback mechanisms possessed by the brain and would motivate further in-vivo investigation. We also model the interaction of the hypercapnic response with dynamic cerebral autoregulation (dCA), the collection of mechanisms that the brain possesses to maintain near constant CBF despite perturbations in pressure, and show how the dCA mechanisms, which otherwise tend to be overlooked when analysing experimental results of cerebrovascular reactivity, could play a significant role in shaping the CBF response to elevations in [Formula: see text] . Such in-silico models can be used in tandem with in-vivo experiments to expand our understanding of cerebrovascular diseases, which continue to be among the leading causes of morbidity and mortality in humans.
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Affiliation(s)
- Ali Daher
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, United Kingdom.
| | - Stephen Payne
- Institute of Applied Mechanics, National Taiwan University, Taiwan
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3
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Sayin ES, Duffin J, Stumpo V, Bellomo J, Piccirelli M, Poublanc J, Wijeya V, Para A, Pangalu A, Bink A, Nemeth B, Kulcsar Z, Mikulis DJ, Fisher JA, Sobczyk O, Fierstra J. Assessing Perfusion in Steno-Occlusive Cerebrovascular Disease Using Transient Hypoxia-Induced Deoxyhemoglobin as a Dynamic Susceptibility Contrast Agent. AJNR Am J Neuroradiol 2023; 45:37-43. [PMID: 38164571 PMCID: PMC10756578 DOI: 10.3174/ajnr.a8068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 11/01/2023] [Indexed: 01/03/2024]
Abstract
BACKGROUND AND PURPOSE Resting brain tissue perfusion in cerebral steno-occlusive vascular disease can be assessed by MR imaging using gadolinium-based susceptibility contrast agents. Recently, transient hypoxia-induced deoxyhemoglobin has been investigated as a noninvasive MR imaging contrast agent. Here we present a comparison of resting perfusion metrics using transient hypoxia-induced deoxyhemoglobin and gadolinium-based contrast agents in patients with known cerebrovascular steno-occlusive disease. MATERIALS AND METHODS Twelve patients with steno-occlusive disease underwent DSC MR imaging using a standard bolus of gadolinium-based contrast agent compared with transient hypoxia-induced deoxyhemoglobin generated in the lungs using an automated gas blender. A conventional multi-slice 2D gradient echo sequence was used to acquire the perfusion data and analyzed using a standard tracer kinetic model. MTT, relative CBF, and relative CBV maps were generated and compared between contrast agents. RESULTS The spatial distributions of the perfusion metrics generated with both contrast agents were consistent. Perfusion metrics in GM and WM were not statistically different except for WM MTT. CONCLUSIONS Cerebral perfusion metrics generated with noninvasive transient hypoxia-induced changes in deoxyhemoglobin are very similar to those generated using a gadolinium-based contrast agent in patients with cerebrovascular steno-occlusive disease.
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Affiliation(s)
- Ece Su Sayin
- From the Department of Physiology (E.S.S., J.D., J.A.F.), University of Toronto, Toronto, Ontario, Canada
- Joint Department of Medical Imaging and the Functional Neuroimaging Lab (E.S.S., J.P., V.W., A. Para, D.J.M., O.S.), University Health Network, Toronto, Ontario, Canada
| | - James Duffin
- From the Department of Physiology (E.S.S., J.D., J.A.F.), University of Toronto, Toronto, Ontario, Canada
- Department of Anesthesia and Pain Management (J.D., J.A.F.), University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Vittorio Stumpo
- Department of Neurosurgery (V.S., J.B. J.F.), University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Jacopo Bellomo
- Department of Neurosurgery (V.S., J.B. J.F.), University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Marco Piccirelli
- Department of Neuroradiology and Clinical Neuroscience Center (M.P., A. Pangalu, A.B., B.N., Z.K.), University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Julien Poublanc
- Joint Department of Medical Imaging and the Functional Neuroimaging Lab (E.S.S., J.P., V.W., A. Para, D.J.M., O.S.), University Health Network, Toronto, Ontario, Canada
| | - Vepeson Wijeya
- Joint Department of Medical Imaging and the Functional Neuroimaging Lab (E.S.S., J.P., V.W., A. Para, D.J.M., O.S.), University Health Network, Toronto, Ontario, Canada
| | - Andrea Para
- Joint Department of Medical Imaging and the Functional Neuroimaging Lab (E.S.S., J.P., V.W., A. Para, D.J.M., O.S.), University Health Network, Toronto, Ontario, Canada
| | - Athina Pangalu
- Department of Neuroradiology and Clinical Neuroscience Center (M.P., A. Pangalu, A.B., B.N., Z.K.), University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Andrea Bink
- Department of Neuroradiology and Clinical Neuroscience Center (M.P., A. Pangalu, A.B., B.N., Z.K.), University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Bence Nemeth
- Department of Neuroradiology and Clinical Neuroscience Center (M.P., A. Pangalu, A.B., B.N., Z.K.), University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Zsolt Kulcsar
- Department of Neuroradiology and Clinical Neuroscience Center (M.P., A. Pangalu, A.B., B.N., Z.K.), University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - David J Mikulis
- Department of Medical Biophysics (D.J.M.), University of Toronto, Toronto, Ontario, Canada
- Joint Department of Medical Imaging and the Functional Neuroimaging Lab (E.S.S., J.P., V.W., A. Para, D.J.M., O.S.), University Health Network, Toronto, Ontario, Canada
| | - Joseph A Fisher
- From the Department of Physiology (E.S.S., J.D., J.A.F.), University of Toronto, Toronto, Ontario, Canada
- Department of Anesthesia and Pain Management (J.D., J.A.F.), University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Olivia Sobczyk
- Joint Department of Medical Imaging and the Functional Neuroimaging Lab (E.S.S., J.P., V.W., A. Para, D.J.M., O.S.), University Health Network, Toronto, Ontario, Canada
| | - Jorn Fierstra
- Department of Neurosurgery (V.S., J.B. J.F.), University Hospital Zurich, University of Zurich, Zurich, Switzerland
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Pinto J, Blockley NP, Harkin JW, Bulte DP. Modelling spatiotemporal dynamics of cerebral blood flow using multiple-timepoint arterial spin labelling MRI. Front Physiol 2023; 14:1142359. [PMID: 37304817 PMCID: PMC10250662 DOI: 10.3389/fphys.2023.1142359] [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: 01/11/2023] [Accepted: 04/14/2023] [Indexed: 06/13/2023] Open
Abstract
Introduction: Cerebral blood flow (CBF) is an important physiological parameter that can be quantified non-invasively using arterial spin labelling (ASL) imaging. Although most ASL studies are based on single-timepoint strategies, multi-timepoint approaches (multiple-PLD) in combination with appropriate model fitting strategies may be beneficial not only to improve CBF quantification but also to retrieve other physiological information of interest. Methods: In this work, we tested several kinetic models for the fitting of multiple-PLD pCASL data in a group of 10 healthy subjects. In particular, we extended the standard kinetic model by incorporating dispersion effects and the macrovascular contribution and assessed their individual and combined effect on CBF quantification. These assessments were performed using two pseudo-continuous ASL (pCASL) datasets acquired in the same subjects but during two conditions mimicking different CBF dynamics: normocapnia and hypercapnia (achieved through a CO2 stimulus). Results: All kinetic models quantified and highlighted the different CBF spatiotemporal dynamics between the two conditions. Hypercapnia led to an increase in CBF whilst decreasing arterial transit time (ATT) and arterial blood volume (aBV). When comparing the different kinetic models, the incorporation of dispersion effects yielded a significant decrease in CBF (∼10-22%) and ATT (∼17-26%), whilst aBV (∼44-74%) increased, and this was observed in both conditions. The extended model that includes dispersion effects and the macrovascular component has been shown to provide the best fit to both datasets. Conclusion: Our results support the use of extended models that include the macrovascular component and dispersion effects when modelling multiple-PLD pCASL data.
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Affiliation(s)
- Joana Pinto
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, United Kingdom
| | - Nicholas P. Blockley
- David Greenfield Human Physiology Unit, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | | | - Daniel P. Bulte
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, United Kingdom
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Katz BM, Walton LR, Houston KM, Cerri DH, Shih YYI. Putative neurochemical and cell type contributions to hemodynamic activity in the rodent caudate putamen. J Cereb Blood Flow Metab 2023; 43:481-498. [PMID: 36448509 PMCID: PMC10063835 DOI: 10.1177/0271678x221142533] [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: 06/10/2022] [Revised: 09/28/2022] [Accepted: 10/21/2022] [Indexed: 12/02/2022]
Abstract
Functional magnetic resonance imaging (fMRI) is widely used by researchers to noninvasively monitor brain-wide activity. The traditional assumption of a uniform relationship between neuronal and hemodynamic activity throughout the brain has been increasingly challenged. This relationship is now believed to be impacted by heterogeneously distributed cell types and neurochemical signaling. To date, most cell-type- and neurotransmitter-specific influences on hemodynamics have been examined within the cortex and hippocampus of rodent models, where glutamatergic signaling is prominent. However, neurochemical influences on hemodynamics are relatively unknown in largely GABAergic brain regions such as the rodent caudate putamen (CPu). Given the extensive contribution of CPu function and dysfunction to behavior, and the increasing focus on this region in fMRI studies, improved understanding of CPu hemodynamics could have broad impacts. Here we discuss existing findings on neurochemical contributions to hemodynamics as they may relate to the CPu with special consideration for how these contributions could originate from various cell types and circuits. We hope this review can help inform the direction of future studies as well as interpretation of fMRI findings in the CPu.
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Affiliation(s)
- Brittany M Katz
- Neuroscience Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Lindsay R Walton
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Kaiulani M Houston
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, New York University Grossman School of Medicine, New York, NY, USA
| | - Domenic H Cerri
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Yen-Yu Ian Shih
- Neuroscience Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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6
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Kecskés S, Menyhárt Á, Bari F, Farkas E. Nimodipine augments cerebrovascular reactivity in aging but runs the risk of local perfusion reduction in acute cerebral ischemia. Front Aging Neurosci 2023; 15:1175281. [PMID: 37181624 PMCID: PMC10174256 DOI: 10.3389/fnagi.2023.1175281] [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: 02/27/2023] [Accepted: 04/05/2023] [Indexed: 05/16/2023] Open
Abstract
Introduction The efficacy of cerebrovascular reactivity (CVR) is taken as an indicator of cerebrovascular health. Methods and Results We found that CVR tested with the inhalation of 10 % CO2 declined in the parietal cortex of 18-20-month-old rats. The CVR deficit in old rats was coincident with cerebrovascular smooth muscle cell and astrocyte senescence, revealed by the immuno-labeling of the cellular senescence marker p16 in these cells. In a next series of experiments, CVR was severely impaired in the acute phase of incomplete global forebrain ischemia produced by the bilateral occlusion of the common carotid arteries in young adult rats. In acute ischemia, CVR impairment often manifested as a perfusion drop rather than blood flow elevation in response to hypercapnia. Next, nimodipine, an L-type voltage-gated calcium channel antagonist was administered topically to rescue CVR in both aging, and cerebra ischemia. Nimodipine augmented CVR in the aged brain, but worsened CVR impairment in acute cerebral ischemia. Discussion A careful evaluation of benefits and side effects of nimodipine is recommended, especially in acute ischemic stroke.
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Affiliation(s)
- Szilvia Kecskés
- Cerebral Blood Flow and Metabolism Research Group, Hungarian Centre of Excellence for Molecular Medicine – University of Szeged, Szeged, Hungary
- Department of Cell Biology and Molecular Medicine, Albert Szent-Györgyi Medical School and Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Ákos Menyhárt
- Cerebral Blood Flow and Metabolism Research Group, Hungarian Centre of Excellence for Molecular Medicine – University of Szeged, Szeged, Hungary
- Department of Cell Biology and Molecular Medicine, Albert Szent-Györgyi Medical School and Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Ferenc Bari
- Department of Medical Physics and Informatics, Albert Szent-Györgyi Medical School and Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Eszter Farkas
- Cerebral Blood Flow and Metabolism Research Group, Hungarian Centre of Excellence for Molecular Medicine – University of Szeged, Szeged, Hungary
- Department of Cell Biology and Molecular Medicine, Albert Szent-Györgyi Medical School and Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
- *Correspondence: Eszter Farkas,
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Shams S, Prokopiou P, Esmaelbeigi A, Mitsis GD, Chen JJ. Modeling the dynamics of cerebrovascular reactivity to carbon dioxide in fMRI under task and resting-state conditions. Neuroimage 2023; 265:119758. [PMID: 36442732 DOI: 10.1016/j.neuroimage.2022.119758] [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: 07/06/2022] [Revised: 11/11/2022] [Accepted: 11/18/2022] [Indexed: 11/26/2022] Open
Abstract
Conventionally, cerebrovascular reactivity (CVR) is estimated as the amplitude of the hemodynamic response to vascular stimuli, most commonly carbon dioxide (CO2). While the CVR amplitude has established clinical utility, the temporal characteristics of CVR (dCVR) have been increasingly explored and may yield even more pathology-sensitive parameters. This work is motivated by the current need to evaluate the feasibility of dCVR modeling in various experimental conditions. In this work, we present a comparison of several recently published/utilized model-based deconvolution (response estimation) approaches for estimating the CO2 response function h(t), including maximum a posteriori likelihood (MAP), inverse logit (IL), canonical correlation analysis (CCA), and basis expansion (using Gamma and Laguerre basis sets). To aid the comparison, we devised a novel simulation framework that incorporates a wide range of SNRs, ranging from 10 to -7 dB, representative of both task and resting-state CO2 changes. In addition, we built ground-truth h(t) into our simulation framework, overcoming the conventional limitation that the true h(t) is unknown. Moreover, to best represent realistic noise found in fMRI scans, we extracted noise from in-vivo resting-state scans. Furthermore, we introduce a simple optimization of the CCA method (CCAopt) and compare its performance to these existing methods. Our findings suggest that model-based methods can accurately estimate dCVR even amidst high noise (i.e. resting-state), and in a manner that is largely independent of the underlying model assumptions for each method. We also provide a quantitative basis for making methodological choices, based on the desired dCVR parameters, the estimation accuracy and computation time. The BEL method provided the highest accuracy and robustness, followed by the CCAopt and IL methods. Of the three, the CCAopt method has the lowest computational requirements. These findings lay the foundation for wider adoption of dCVR estimation in CVR mapping.
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Affiliation(s)
- Seyedmohammad Shams
- Rotman Research Institute, Baycrest Health Sciences, Canada; Department of Neurology, Henry Ford Health, USA
| | - Prokopis Prokopiou
- Department of Radiology, Gordon Center for Medical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | | | | | - J Jean Chen
- Rotman Research Institute, Baycrest Health Sciences, Canada; Department of Bioengineering, McGill University, Canada; Department of Medical Biophysics, University of Toronto, Canada; Institute of Biomedical Engineering, University of Toronto, Canada.
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Sayin ES, Schulman J, Poublanc J, Levine HT, Raghavan LV, Uludag K, Duffin J, Fisher JA, Mikulis DJ, Sobczyk O. Investigations of hypoxia-induced deoxyhemoglobin as a contrast agent for cerebral perfusion imaging. Hum Brain Mapp 2022; 44:1019-1029. [PMID: 36308389 PMCID: PMC9875930 DOI: 10.1002/hbm.26131] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 08/01/2022] [Accepted: 10/09/2022] [Indexed: 01/28/2023] Open
Abstract
The assessment of resting perfusion measures (mean transit time, cerebral blood flow, and cerebral blood volume) with magnetic resonance imaging currently requires the presence of a susceptibility contrast agent such as gadolinium. Here, we present an initial comparison between perfusion measures obtained using hypoxia-induced deoxyhemoglobin and gadolinium in healthy study participants. We hypothesize that resting cerebral perfusion measures obtained using precise changes of deoxyhemoglobin concentration will generate images comparable to those obtained using a clinical standard, gadolinium. Eight healthy study participants were recruited (6F; age 23-60). The study was performed using a 3-Tesla scanner with an eight-channel head coil. The experimental protocol consisted of a high-resolution T1-weighted scan followed by two BOLD sequence scans in which each participant underwent a controlled bolus of transient pulmonary hypoxia, and subsequently received an intravenous bolus of gadolinium. The resting perfusion measures calculated using hypoxia-induced deoxyhemoglobin and gadolinium yielded maps that looked spatially comparable. There was no statistical difference between methods in the average voxel-wise measures of mean transit time, relative cerebral blood flow and relative cerebral blood volume, in the gray matter or white matter within each participant. We conclude that perfusion measures generated with hypoxia-induced deoxyhemoglobin are spatially and quantitatively comparable to those generated from a gadolinium injection in the same healthy participant.
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Affiliation(s)
- Ece Su Sayin
- Department of PhysiologyUniversity of TorontoTorontoOntarioCanada,Department of Anaesthesia and Pain ManagementUniversity Health Network, University of TorontoTorontoOntarioCanada
| | - Jacob Schulman
- Department of Medical BiophysicsUniversity of TorontoTorontoOntarioCanada,Techna Institute, University Health NetworkTorontoCanada
| | - Julien Poublanc
- Joint Department of Medical Imaging and the Functional Neuroimaging LabUniversity Health NetworkTorontoOntarioCanada
| | - Harrison T. Levine
- Department of PhysiologyUniversity of TorontoTorontoOntarioCanada,Department of Anaesthesia and Pain ManagementUniversity Health Network, University of TorontoTorontoOntarioCanada
| | - Lakshmikumar Venkat Raghavan
- Department of Anaesthesia and Pain ManagementUniversity Health Network, University of TorontoTorontoOntarioCanada
| | - Kamil Uludag
- Techna Institute, University Health NetworkTorontoCanada,Joint Department of Medical Imaging and the Functional Neuroimaging LabUniversity Health NetworkTorontoOntarioCanada,Center for Neuroscience Imaging Research, Institute for Basic Science and Department of Biomedical EngineeringSungkyunkwan UniversitySuwonRepublic of Korea
| | - James Duffin
- Department of PhysiologyUniversity of TorontoTorontoOntarioCanada,Department of Anaesthesia and Pain ManagementUniversity Health Network, University of TorontoTorontoOntarioCanada
| | - Joseph A. Fisher
- Department of PhysiologyUniversity of TorontoTorontoOntarioCanada,Department of Anaesthesia and Pain ManagementUniversity Health Network, University of TorontoTorontoOntarioCanada
| | - David J. Mikulis
- Techna Institute, University Health NetworkTorontoCanada,Joint Department of Medical Imaging and the Functional Neuroimaging LabUniversity Health NetworkTorontoOntarioCanada
| | - Olivia Sobczyk
- Department of Anaesthesia and Pain ManagementUniversity Health Network, University of TorontoTorontoOntarioCanada,Joint Department of Medical Imaging and the Functional Neuroimaging LabUniversity Health NetworkTorontoOntarioCanada
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9
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He X, Dou W, Shi H. The Diagnostic Value of the Combined 3D Pseudo-Continuous Arterial Spin Labeling and Diffusion Kurtosis Imaging in Patients With Binswanger’s Disease. Front Neurosci 2022; 16:853422. [PMID: 35844226 PMCID: PMC9280636 DOI: 10.3389/fnins.2022.853422] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 06/09/2022] [Indexed: 12/04/2022] Open
Abstract
Background and Purpose The clinical diagnosis of Binswanger’s disease (BD), a chronic progressive form of subcortical vascular dementia, remains challenging. 3D pseudo-continuous arterial-spin-labeling (pcASL) and diffusion kurtosis imaging (DKI) can quantitatively reveal the microcirculation changes and heterogeneity of white matter (WM), respectively. We thus aimed to determine the diagnostic value of the combined 3D-pcASL and DKI in BD. Materials and Methods A total of 35 patients with BD and 33 healthy controls underwent 3D-ASL and DKI experiments. The perfusion parameter of cerebral blood flow (CBF), diffusion parameters of fractional anisotropy (FA), mean/axial/radial diffusivity (MD/Da/Dr), and kurtosis parameters of anisotropy fraction of kurtosis (FAk) and mean/axial/radial kurtosis MK/Ka/Kr were obtained to quantitatively measure the parametric distributions of functional brain subregions. One-way analysis of variance and post hoc t-test were applied to explore the different distributions of DKI/ASL-derived parameters among brain subregions of BD. In addition, all region-specific DKI/ASL parameters were separately analyzed in Pearson correlation analysis to investigate the relationship with Mini-Mental State Examination (MMSE), a typical clinical scale for cognitive function assessment in patients with BD. Results FA/FAk/MK/Ka/Kr was significantly declined in all WM hyperintensities (WMHs) of BD compared with healthy controls, while the corresponding MD/Da/Dr was significantly increased (all p < 0.005). In addition, significant changes, similar to the WMHs of patients with BD, were also observed in almost all DKI parameters in WM normal areas and genu/splenium of the corpus callosum (GCC/SCC) in BD (p < 0.005). Finally, CBF was significantly reduced in all of the above regions we measured in patients with BD (p < 0.005). For patients with BD, MMSE showed a negative correlation with MD/Da in thalamus (r = −0.42/−0.58; p < 0.05), and a positive correlation with CBF in PWM/TWM (r = 0.49/0.39; p < 0.05). Using receiver operating characteristic (ROC) analysis, FA/FAk/Kr in GCC, CBF/FA/Dr/FAk in SCC, MD/Da/Ka in thalamus, and the combined FA/MD/Dr/CBF in TWM showed high accuracy [area under the curves (AUCs) 0.957/0.946/0.942/0.986] in distinguishing patients with BD from healthy controls. Conclusion We found that combined DKI and 3D-ASL are helpful in diagnosing patients with BD, especially with FA, MD, Dr, and CBF in the temporal WM region. Additionally, the kurtosis parameters of DKI can sensitively monitor the potentially damaged WM areas in patients with BD patients, adding complementary clinical value.
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Affiliation(s)
- Xiaoyi He
- Department of Radiology, The First Affiliated Hospital of Shandong First Medical University and Shandong Provincial Qianfoshan Hospital, Jinan, China
- Department of Radiology, The Second Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China
| | | | - Hao Shi
- Department of Radiology, The First Affiliated Hospital of Shandong First Medical University and Shandong Provincial Qianfoshan Hospital, Jinan, China
- *Correspondence: Hao Shi,
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10
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Whitehead SN, Bruno A, Burns JM, Carmichael ST, Csiszar A, Edwards JD, Elahi FM, Faraco G, Gould DB, Gustafson DR, Hachinski V, Rosenberg G, Sorond FA, Shih AY, Tse KH, Ungvari Z, Wilcock DM, Zuloaga KL, Barone FC. Expanding the horizon of research into the pathogenesis of the white matter diseases: Proceedings of the 2021 Annual Workshop of the Albert Research Institute for White Matter and Cognition. GeroScience 2022; 44:25-37. [PMID: 34606040 PMCID: PMC8488071 DOI: 10.1007/s11357-021-00461-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 09/14/2021] [Indexed: 12/14/2022] Open
Abstract
White matter pathologies are critically involved in the etiology of vascular cognitive impairment-dementia (VCID), Alzheimer's disease (AD), and Alzheimer's disease and related diseases (ADRD), and therefore need to be considered a treatable target ( Roseborough A, Hachinski V, Whitehead S. White matter degeneration - a treatable target? Roseborough et al. JAMA Neurol [Internet]. 2020 Apr 27;77(7):793-4, [1] . To help address this often-missed area of research, several workshops have been sponsored by the Leo and Anne Albert Charitable Trust since 2015, resulting in the incorporation of "The Albert Research Institute for White Matter and Cognition" in 2020. The first annual "Institute" meeting was held virtually on March 3-4, 2021. The Institute provides a forum and workspace for communication and support of the advancement of white matter science and research to better understand the evolution and prevention of dementia. It serves as a platform for young investigator development, to introduce new data and debate biology mechanisms and new ideas, and to encourage and support new research collaborations and directions to clarify how white matter changes, with other genetic and health risk factors, contribute to cognitive impairment. Similar to previous Albert Trust-sponsored workshops (Barone et al. in J Transl Med 14:1-14, [2]; Sorond et al. in GeroScience 42:81-96, [3]), established expert investigators were identified and invited to present. Opportunities to attend and present were also extended by invitation to talented research fellows and younger scientists. Also, updates on institute-funded research collaborations were provided and discussed. The summary that follows is a synopsis of topics and discussion covered in the workshop.
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Affiliation(s)
- Shawn N Whitehead
- Department of Anatomy and Cell Biology, Western University, London, ON, N6A 3K7, Canada.
| | - Askiel Bruno
- Department of Neurology, Medical College of Georgia at Augusta University, Augusta, GA, 30912, USA
| | - Jeffrey M Burns
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS, USA
| | - S Thomas Carmichael
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095, USA
| | - Anna Csiszar
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Translational Medicine, Semmelweis University, Budapest, Hungary
| | - Jodi D Edwards
- University of Ottawa Heart Institute, Ottawa, Canada
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, K1G 5Z3, Canada
| | - Fanny M Elahi
- Memory and Aging Center, UCSF Weill Institute for Neurosciences, 675 Nelson Rising Lane, Suite 190, San Francisco, CA, 94158, USA
| | - Giuseppe Faraco
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, 10065, USA
| | - Douglas B Gould
- Departments of Ophthalmology and Anatomy, and Institute for Human Genetics, School of Medicine, University of California, San Francisco, 94143, USA
| | - Deborah R Gustafson
- Department of Neurology, Section for NeuroEpidemiology, State University of New York Downstate Health Sciences University, New York, Brooklyn, 11203, USA
| | - Vladimir Hachinski
- Department of Clinical Neurological Sciences, Western University, London, ON, N6A 5C1, Canada
| | - Gary Rosenberg
- UNM Health Sciences Center, University of New Mexico, Albuquerque, NM, 87106, USA
| | | | - Andy Y Shih
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute; Department of Pediatrics; Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Kai Hei Tse
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Kowloon, Hong Kong
| | - Zoltan Ungvari
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Translational Medicine, Semmelweis University, Budapest, Hungary
| | - Donna M Wilcock
- Sanders-Brown Center on Aging; Department of Neurology, Department of Behavioral Science, University of Kentucky, Lexington, KY, 40536, USA
| | - Kristen L Zuloaga
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, 12208, USA
| | - Frank C Barone
- Department of Neurology, SUNY Downstate Health Sciences University, Brooklyn, NY, 11203, USA
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11
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Hong CCH, Fallon JH, Friston KJ. fMRI Evidence for Default Mode Network Deactivation Associated with Rapid Eye Movements in Sleep. Brain Sci 2021; 11:brainsci11111528. [PMID: 34827529 PMCID: PMC8615877 DOI: 10.3390/brainsci11111528] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/12/2021] [Accepted: 11/16/2021] [Indexed: 11/25/2022] Open
Abstract
System-specific brain responses—time-locked to rapid eye movements (REMs) in sleep—are characteristically widespread, with robust and clear activation in the primary visual cortex and other structures involved in multisensory integration. This pattern suggests that REMs underwrite hierarchical processing of visual information in a time-locked manner, where REMs index the generation and scanning of virtual-world models, through multisensory integration in dreaming—as in awake states. Default mode network (DMN) activity increases during rest and reduces during various tasks including visual perception. The implicit anticorrelation between the DMN and task-positive network (TPN)—that persists in REM sleep—prompted us to focus on DMN responses to temporally-precise REM events. We timed REMs during sleep from the video recordings and quantified the neural correlates of REMs—using functional MRI (fMRI)—in 24 independent studies of 11 healthy participants. A reanalysis of these data revealed that the cortical areas exempt from widespread REM-locked brain activation were restricted to the DMN. Furthermore, our analysis revealed a modest temporally-precise REM-locked decrease—phasic deactivation—in key DMN nodes, in a subset of independent studies. These results are consistent with hierarchical predictive coding; namely, permissive deactivation of DMN at the top of the hierarchy (leading to the widespread cortical activation at lower levels; especially the primary visual cortex). Additional findings indicate REM-locked cerebral vasodilation and suggest putative mechanisms for dream forgetting.
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Affiliation(s)
- Charles Chong-Hwa Hong
- Patuxent Institution, Correctional Mental Health Center—Jessup, Jessup, MD 20794, USA
- Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University, Baltimore, MD 21205, USA
- Correspondence: ; Tel.: +1-410-596-1956
| | - James H. Fallon
- Department of Anatomy and Neurobiology, University of California, Irvine, CA 92697, USA;
- Department of Psychiatry and Human Behavior, University of California, Irvine, CA 92697, USA
| | - Karl J. Friston
- The Well Come Centre for Human Neuroimaging, Institute of Neurology, University College London, London WC1N 3AR, UK;
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12
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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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13
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Hemodialysis Patients Have Impaired Cerebrovascular Reactivity to CO 2 Compared to Chronic Kidney Disease Patients and Healthy Controls: A Pilot Study. Kidney Int Rep 2021; 6:1868-1877. [PMID: 34307981 PMCID: PMC8258459 DOI: 10.1016/j.ekir.2021.04.005] [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: 12/02/2020] [Revised: 03/11/2021] [Accepted: 04/05/2021] [Indexed: 11/20/2022] Open
Abstract
Introduction Recurrent hemodialysis (HD)–induced ischemia has emerged as a mechanism responsible for cognitive impairment in HD patients. Impairment of cerebrovascular function in HD patients may render the brain vulnerable to HD-induced ischemic injury. Cerebrovascular reactivity to CO2 (CVR) is a noninvasive marker of cerebrovascular function. Whether CVR is impaired in HD patients is unknown. In this study, we compared CVR between healthy participants, HD patients, and chronic kidney disease (CKD) patients not yet requiring dialysis. Methods This was a single-center prospective observational study carried out at Kidney Clinical Research Unit in London, Canada. We used carefully controlled hypercapnia to interrogate brain vasomotor control. Transcranial Doppler was combined with 10–mm Hg step changes in CO2 from baseline to hypercapnia (intervention) and back to baseline (recovery) to assess CVR in 8 HD, 10 CKD, and 17 heathy participants. Results HD patients had lower CVR than CKD or healthy participants during both intervention and recovery (P < 0.0001). There were no differences in CVR between healthy and CKD participants during either intervention (P = 0.88) or recovery (P = 0.99). The impaired CVR in HD patients was independent of CO2-induced changes in blood pressure, heart rate, cardiac output, or dialysis vintage. In the CKD group, CVR was not associated with the estimated glomerular filtration rate. Conclusions Our study shows that HD patients have impaired CVR relative to CKD and healthy participants. This renders HD patients vulnerable to ischemic injury during circulatory stress of dialysis and may contribute to the pathogenesis of cognitive impairment.
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14
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Benson JC, Seyedsaadat SM, Mark I, Nasr DM, Rabinstein AA, Kallmes DF, Brinjikji W. Leukoaraiosis and acute ischemic stroke: 90-day clinical outcome following endovascular recanalization, with proposed "L-ASPECTS". J Neurointerv Surg 2021; 13:384-389. [PMID: 32487764 DOI: 10.1136/neurintsurg-2020-015957] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 04/20/2020] [Accepted: 04/23/2020] [Indexed: 02/02/2023]
Abstract
BACKGROUND To assess if leukoaraiosis severity is associated with outcome in patients with acute ischemic stroke (AIS) following endovascular thrombectomy, and to propose a leukoaraiosis-related modification to the ASPECTS score. METHODS A retrospective review was completed of AIS patients that underwent mechanical thrombectomy for anterior circulation large vessel occlusion. The primary outcome measure was 90-day mRS. A proposed Leukoaraiosis-ASPECTS ("L-ASPECTS") was calculated by subtracting from the traditional ASPECT based on leukoaraiosis severity (1 point subtracted if mild, 2 if moderate, 3 if severe). L-ASEPCTS score performance was validated using a consecutive cohort of 75 AIS LVO patients. RESULTS 174 patients were included in this retrospective analysis: average age: 68.0±9.1. 28 (16.1%) had no leukoaraiosis, 66 (37.9%) had mild, 62 (35.6%) had moderate, and 18 (10.3%) had severe. Leukoaraiosis severity was associated with worse 90-day mRS among all patients (P=0.0005). Both L-ASPECTS and ASPECTS were associated with poor outcomes, but the area under the curve (AUC) was higher with L-ASPECTS (P<0.0001 and AUC=0.7 for L-ASPECTS; P=0.04 and AUC=0.59 for ASPECTS). In the validation cohort, the AUC for L-ASPECTS was 0.79 while the AUC for ASPECTS was 0.70. Of patients that had successful reperfusion (mTICI 2b/3), the AUC for traditional ASPECTS in predicting good functional outcome was 0.80: AUC for L-ASPECTS was 0.89. CONCLUSIONS Leukoaraiosis severity on pre-mechanical thrombectomy NCCT is associated with worse 90-day outcome in patients with AIS following endovascular recanalization, and is an independent risk factor for worse outcomes. A proposed L-ASPECTS score had stronger association with outcome than the traditional ASPECTS score.
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Affiliation(s)
| | | | - Ian Mark
- Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - Deena M Nasr
- Neurology, Mayo Clinic, Rochester, Minnesota, USA
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15
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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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16
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Champagne AA, Bhogal AA. Insights Into Cerebral Tissue-Specific Response to Respiratory Challenges at 7T: Evidence for Combined Blood Flow and CO 2-Mediated Effects. Front Physiol 2021; 12:601369. [PMID: 33584344 PMCID: PMC7876301 DOI: 10.3389/fphys.2021.601369] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 01/06/2021] [Indexed: 11/16/2022] Open
Abstract
Cerebrovascular reactivity (CVR) mapping is finding increasing clinical applications as a non-invasive probe for vascular health. Further analysis extracting temporal delay information from the CVR response provide additional insight that reflect arterial transit time, blood redistribution, and vascular response speed. Untangling these factors can help better understand the (patho)physiology and improve diagnosis/prognosis associated with vascular impairments. Here, we use hypercapnic (HC) and hyperoxic (HO) challenges to gather insight about factors driving temporal delays between gray-matter (GM) and white-matter (WM). Blood Oxygen Level Dependent (BOLD) datasets were acquired at 7T in nine healthy subjects throughout BLOCK- and RAMP-HC paradigms. In a subset of seven participants, a combined HC+HO block, referred as the “BOOST” protocol, was also acquired. Tissue-based differences in Rapid Interpolation at Progressive Time Delays (RIPTiDe) were compared across stimulus to explore dynamic (BLOCK-HC) versus progressive (RAMP-HC) changes in CO2, as well as the effect of bolus arrival time on CVR delays (BLOCK-HC versus BOOST). While GM delays were similar between the BLOCK- (21.80 ± 10.17 s) and RAMP-HC (24.29 ± 14.64 s), longer WM lag times were observed during the RAMP-HC (42.66 ± 17.79 s), compared to the BLOCK-HC (34.15 ± 10.72 s), suggesting that the progressive stimulus may predispose WM vasculature to longer delays due to the smaller arterial content of CO2 delivered to WM tissues, which in turn, decreases intravascular CO2 gradients modulating CO2 diffusion into WM tissues. This was supported by a maintained ∼10 s offset in GM (11.66 ± 9.54 s) versus WM (21.40 ± 11.17 s) BOOST-delays with respect to the BLOCK-HC, suggesting that the vasoactive effect of CO2 remains constant and that shortening of BOOST delays was be driven by blood arrival reflected through the non-vasodilatory HO contrast. These findings support that differences in temporal and magnitude aspects of CVR between vascular networks reflect a component of CO2 sensitivity, in addition to redistribution and steal blood flow effects. Moreover, these results emphasize that the addition of a BOOST paradigm may provide clinical insights into whether vascular diseases causing changes in CVR do so by way of severe blood flow redistribution effects, alterations in vascular properties associated with CO2 diffusion, or changes in blood arrival time.
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Affiliation(s)
- Allen A Champagne
- Centre for Neuroscience Studies, Queen's University, Kingston, ON, Canada.,School of Medicine, Queen's University, Kingston, ON, Canada
| | - Alex A Bhogal
- Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands
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17
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Yang T, Zhang F. Targeting Transcription Factor Nrf2 (Nuclear Factor Erythroid 2-Related Factor 2) for the Intervention of Vascular Cognitive Impairment and Dementia. Arterioscler Thromb Vasc Biol 2020; 41:97-116. [PMID: 33054394 DOI: 10.1161/atvbaha.120.314804] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Vascular cognitive impairment and dementia (VCID) is an age-related, mild to severe mental disability due to a broad panel of cerebrovascular disorders. Its pathobiology involves neurovascular dysfunction, blood-brain barrier disruption, white matter damage, microRNAs, oxidative stress, neuroinflammation, and gut microbiota alterations, etc. Nrf2 (Nuclear factor erythroid 2-related factor 2) is the master regulator of redox status and controls the transcription of a panel of antioxidative and anti-inflammatory genes. By interacting with NF-κB (nuclear factor-κB), Nrf2 also fine-tunes the cellular oxidative and inflammatory balance. Aging is associated with Nrf2 dysfunction, and increasing evidence has proved the role of Nrf2 in mitigating the VCID process. Based on VCID pathobiologies and Nrf2 studies from VCID and other brain diseases, we point out several hypothetical Nrf2 targets for VCID management, including restoration of endothelial function and neurovascular coupling, preservation of blood-brain barrier integrity, reduction of amyloidopathy, promoting white matter integrity, and mitigating oxidative stress and neuroinflammation. Collectively, the Nrf2 pathway could be a promising direction for future VCID research. Targeting Nrf2 would shed light on VCID managing strategies.
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Affiliation(s)
- Tuo Yang
- Department of Neurology, Pittsburgh Institute of Brain Disorders and Recovery, University of Pittsburgh, PA
| | - Feng Zhang
- Department of Neurology, Pittsburgh Institute of Brain Disorders and Recovery, University of Pittsburgh, PA
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18
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Ni L, Zhang B, Yang D, Qin R, Xu H, Ma J, Shao P, Xu Y. Lower Cerebrovascular Reactivity Contributed to White Matter Hyperintensity-Related Cognitive Impairment: A Resting-State Functional MRI Study. J Magn Reson Imaging 2020; 53:703-711. [PMID: 32996183 DOI: 10.1002/jmri.27376] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 09/05/2020] [Accepted: 09/08/2020] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Impaired cerebrovascular reactivity (CVR) plays an important role in the pathophysiology of white matter hyperintensities (WMHs). The pathogenesis of CVR in the development of WMH-related cognitive impairment (CI) remains poorly understood. PURPOSE To detect the CVR status in WMH subjects with/without CI by using a resting-state blood oxygenation level-dependent (BOLD) approach and to explore the mediating relationships among CVR, WMH, and cognitive level. STUDY TYPE Prospective. SUBJECTS Subjects with moderate to severe WMH (with CI [WMH-CI], n = 68; without CI [WMH-no-CI, n = 63) as well as normal controls (NCs, n = 87). FIELD STRENGTH/SEQUENCE 3.0T with gradient-recalled echoplanar imaging and 3D fluid-attenuated inversion recovery. ASSESSMENT The CVR, WMH volume, and cognitive level were assessed. The CVR map was derived using BOLD signal obtained from resting-state functional MRI data. STATISTICAL TESTS CVR maps were compared among the three groups. Partial correlation analyses were performed to correlate impaired CVR with WMH volume and cognitive test scores. Mediation analysis was conducted to determine whether WMH acted as a mediating factor between CVR and cognitive function. RESULTS Compared with the NC group, both WMH groups showed reduced CVR in the left hemisphere (P < 0.05). The WMH-CI group showed further decreased CVR in the left frontal area, when compared with the WMH-no-CI group (P < 0.05). In the WMH-CI group, the lower CVR in left frontal area was a strong indicator of poor performance on general cognition (r = 0.311), executive function (r = 0.362), and information processing speed (r = 0.399) (all P < 0.05). Periventricular WMH (PWMH) volume mediated these correlations, the β and 95% bootstrap confidence intervals were (0.5097, [0.1498,1.1385]), (-0.4081, [-1.0256,-0.1363]), and (-0.5576, [-1.4666,-0.1538]), respectively. DATA CONCLUSION WMH-CI subjects showed a greater reduction of CVR derived from a resting-state BOLD approach in the left frontal area than WMH-no-CI subjects. Cognition was highly dependent on the integrity of cerebrovascular reactivity and mediated by PWMH burden. LEVEL OF EVIDENCE 4 TECHNICAL EFFICACY: Stage 2.
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Affiliation(s)
- Ling Ni
- Department of Neurology, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China.,Department of Radiology, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| | - Bing Zhang
- Department of Radiology, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| | - Dan Yang
- Department of Neurology, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| | - Ruomeng Qin
- Department of Neurology, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| | - Hengheng Xu
- Department of Neurology, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| | - Junyi Ma
- Department of Neurology, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| | - Pengfei Shao
- Department of Neurology, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| | - Yun Xu
- Department of Neurology, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
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19
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Wang M, Feng H, Zhang S, Luo Z, Liang Y, Xu Y, Mei B, Kong Z, Liu Y. Association between red blood cell distribution width and white matter hyperintensities: A large-scale cross-sectional study. Brain Behav 2020; 10:e01739. [PMID: 32683781 PMCID: PMC7503097 DOI: 10.1002/brb3.1739] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 05/07/2020] [Accepted: 06/06/2020] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Red blood cell distribution width (RDW) is a strong prognostic marker for various medical conditions, such as ischemic strokes. However, the relationships between higher RDW and the subtypes of white matter hyperintensities (WMHs) remain unclear. Hence, this study aimed to thoroughly evaluate the relationships between RDW and the subtypes of WMHs. PATIENTS AND METHODS This cross-sectional study was a retrospective analysis of hospital database (Dongguan Medical System, from April 2015 to February 2017). The presence and subtypes of WMHs were evaluated using Fazekas score with the T2WI-FLAIR brain images from a 1.5-T MRI system. The overall sample was randomly split in half. One of the two split-half samples was used for determining the optimal cutoff value of higher RDW and another for further statistical analyses. RESULTS A total of 555 subjects with WMHs and 642 controls were recruited. The optimal cutoff value of higher RDW was 13.25%. Logistic regression revealed that higher RDW (≥13.25%) was positively associated with periventricular WMHs (adjusted OR = 1.81, 95% CI: 1.16-2.82, p = .009). However, higher RDW was not associated with total WMHs (adjusted OR = 1.52, 95% CI: 0.99-2.33, p = .057) and deep WMHs (adjusted OR = 1.21, 95% CI: 0.76-1.94, p = .426). CONCLUSION Our findings suggested that higher RDW may be independently associated with periventricular WMHs, but not with total WMHs and deep WMHs.
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Affiliation(s)
- Meiyao Wang
- Department of Neurology, Zhongnan Hospital of Wuhan University, Wuhan, China.,Department of Ultrasonography, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Hongliang Feng
- Department of Neurology, Zhongnan Hospital of Wuhan University, Wuhan, China.,Department of Psychiatry, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., China
| | - Shuaimei Zhang
- Department of Neurology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Zhengjin Luo
- Department of Neurology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Yan Liang
- Department of Neurology, The First Affiliated Hospital, Jinan University, Guangzhou, China
| | - Yan Xu
- Department of Neurology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Bin Mei
- Department of Neurology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Zhaohong Kong
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yumin Liu
- Department of Neurology, Zhongnan Hospital of Wuhan University, Wuhan, China
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20
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Vu C, Chai Y, Coloigner J, Nederveen AJ, Borzage M, Bush A, Wood JC. Quantitative perfusion mapping with induced transient hypoxia using BOLD MRI. Magn Reson Med 2020; 85:168-181. [PMID: 32767413 DOI: 10.1002/mrm.28422] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 06/18/2020] [Accepted: 06/19/2020] [Indexed: 12/20/2022]
Abstract
PURPOSE Gadolinium-based dynamic susceptibility contrast (DSC) is commonly used to characterize blood flow in patients with stroke and brain tumors. Unfortunately, gadolinium contrast administration has been associated with adverse reactions and long-term accumulation in tissues. In this work, we propose an alternative deoxygenation-based DSC (dDSC) method that uses a transient hypoxia gas paradigm to deliver a bolus of paramagnetic deoxygenated hemoglobin to the cerebral vasculature for perfusion imaging. METHODS Through traditional DSC tracer kinetic modeling, the MR signal change induced by this hypoxic bolus can be used to generate regional perfusion maps of cerebral blood flow, cerebral blood volume, and mean transit time. This gas paradigm and blood-oxygen-level-dependent (BOLD)-MRI were performed concurrently on a cohort of 66 healthy and chronically anemic subjects (age 23.5 ± 9.7, female 64%). RESULTS Our results showed reasonable global and regional agreement between dDSC and other flow techniques, such as phase contrast and arterial spin labeling. CONCLUSION In this proof-of-concept study, we demonstrated the feasibility of using transient hypoxia to generate a contrast bolus that mimics the effect of gadolinium and yields reasonable perfusion estimates. Looking forward, optimization of the hypoxia boluses and measurement of the arterial-input function is necessary to improve the accuracy of dDSC. Additionally, a cross-validation study of dDSC and DSC in brain tumor and ischemic stroke subjects is warranted to evaluate the clinical diagnostic utility of this approach.
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Affiliation(s)
- Chau Vu
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA
| | - Yaqiong Chai
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA.,Department of Radiology, CIBORG Laboratory, Children's Hospital Los Angeles, Los Angeles, CA, USA
| | - Julie Coloigner
- Department of Radiology, CIBORG Laboratory, Children's Hospital Los Angeles, Los Angeles, CA, USA.,Univ Rennes, CNRS, Inria, Inserm, IRISA UMR 6074, Empenn ERL U 1228, Rennes, France
| | - Aart J Nederveen
- Radiology and Nuclear Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Matthew Borzage
- Division of Neonatology, Fetal and Neonatal Institute, Children's Hospital Los Angeles, Los Angeles, CA, USA.,Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Adam Bush
- Department of Radiology, Stanford University, Stanford, CA, USA.,Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - John C Wood
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA.,Division of Cardiology, Department of Pediatrics and Radiology, Children's Hospital Los Angeles, Los Angeles, CA, USA
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21
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Coloigner J, Vu C, Borzage M, Bush A, Choi S, Miao X, Chai Y, Galarza C, Lepore N, Tamrazi B, Coates TD, Wood JC. Transient Hypoxia Model Revealed Cerebrovascular Impairment in Anemia Using BOLD MRI and Near-Infrared Spectroscopy. J Magn Reson Imaging 2020; 52:1400-1412. [PMID: 32648323 DOI: 10.1002/jmri.27210] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 05/07/2020] [Accepted: 05/08/2020] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Obstructive sleep apnea and nocturnal oxygen desaturations, which are prevalent in sickle cell disease (SCD) and chronic anemia disorders, have been linked to risks of stroke and silent cerebral infarcts (SCI). Cerebrovascular response to intermittent desaturations has not been well studied and may identify patients at greatest risk. PURPOSE To investigate the cerebral dynamic response to induced desaturation in SCD patients with and without SCI, chronic anemia, and healthy subjects. STUDY TYPE Prospective. SUBJECTS Twenty-six SCD patients (age = 21 ± 8.2, female 46.2%), including 15 subjects without SCI and nine subjects with SCI, 15 nonsickle anemic patients (age = 22 ± 5.8, female 66.7%), and 31 controls (age = 28 ± 12.3, female 77.4%). FIELD STRENGTH/SEQUENCE 3T, gradient-echo echo-planar imaging. ASSESSMENT A transient hypoxia challenge of five breaths of 100% nitrogen gas was performed with blood oxygen level-dependent (BOLD) MRI and near-infrared spectroscopy (NIRS) acquisitions. Hypoxia responses were characterized by desaturation depth, time-to-peak, return-to-baseline half-life, and posthypoxia recovery in the BOLD and NIRS time courses. SCI were documented by T2 fluid-attenuation inversion recovery (FLAIR). STATISTICAL TESTS Univariate and multivariate regressions were performed between hypoxic parameters and anemia predictors. Voxelwise two-sample t-statistic maps were used to assess the regional difference in hypoxic responses between anemic and control groups. RESULTS Compared to controls, SCD and chronically anemic patients demonstrated significantly higher desaturation depth (P < 0.01) and shorter return-to-baseline timing response (P < 0.01). Patients having SCI had shorter time-to-peak (P < 0.01), return-to-baseline (P < 0.01), and larger desaturation depth (P < 0.01) in both white matter regions at risk and normal-appearing white matter than patients without infarcts. On multivariate analysis, desaturation depth and timing varied with age, sex, blood flow, white blood cells, and cell-free hemoglobin (r2 = 0.25 for desaturation depth; r2 = 0.18 for time-to-peak; r2 = 0.37 for return-to-baseline). DATA CONCLUSION Transient hypoxia revealed global and regional response differences between anemic and healthy subjects. SCI was associated with extensive heterogeneity of desaturation dynamics, consistent with extensive underlying microvascular remodeling.
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Affiliation(s)
- Julie Coloigner
- CIBORG Laboratory, Department of Radiology, Children's Hospital Los Angeles, Los Angeles, California, USA.,Univ Rennes, CNRS, Inria, Inserm, IRISA UMR 6074, Rennes, France
| | - Chau Vu
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, USA
| | - Matthew Borzage
- Division of Neonatology, Fetal and Neonatal Institute, Children's Hospital Los Angeles, Los Angeles, California, USA.,Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Adam Bush
- Department of Radiology and Department of Electrical Engineering, Stanford University, Stanford, California, USA
| | - Soyoung Choi
- Neuroscience Graduate Program, University of Southern California, Los Angeles, California, USA
| | - Xin Miao
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, USA
| | - Yaqiong Chai
- CIBORG Laboratory, Department of Radiology, Children's Hospital Los Angeles, Los Angeles, California, USA.,Department of Biomedical Engineering, University of Southern California, Los Angeles, California, USA
| | - Cristina Galarza
- Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Natasha Lepore
- CIBORG Laboratory, Department of Radiology, Children's Hospital Los Angeles, Los Angeles, California, USA.,Department of Biomedical Engineering, University of Southern California, Los Angeles, California, USA.,Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Benita Tamrazi
- Department of Radiology, Children's Hospital Los Angeles, Los Angeles, California, USA
| | - Thomas D Coates
- Division of Hematology-Oncology, Department of Pediatrics, Children's Hospital Los Angeles, Los Angeles, California, USA.,Department of Pediatrics and Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - John C Wood
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, USA.,Division of Cardiology, Department of Pediatrics and Radiology, Children's Hospital Los Angeles, Los Angeles, California, USA
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22
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Mutch WAC, El-Gabalawy R, Ryner L, Puig J, Essig M, Kilborn K, Fidler K, Graham MR. Brain BOLD MRI O 2 and CO 2 stress testing: implications for perioperative neurocognitive disorder following surgery. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2020; 24:76. [PMID: 32131878 PMCID: PMC7057494 DOI: 10.1186/s13054-020-2800-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 02/18/2020] [Indexed: 12/17/2022]
Abstract
Background Mechanical ventilation to alter and improve respiratory gases is a fundamental feature of critical care and intraoperative anesthesia management. The range of inspired O2 and expired CO2 during patient management can significantly deviate from values in the healthy awake state. It has long been appreciated that hyperoxia can have deleterious effects on organs, especially the lung and retina. Recent work shows intraoperative end-tidal (ET) CO2 management influences the incidence of perioperative neurocognitive disorder (POND). The interaction of O2 and CO2 on cerebral blood flow (CBF) and oxygenation with alterations common in the critical care and operating room environments has not been well studied. Methods We examine the effects of controlled alterations in both ET O2 and CO2 on cerebral blood flow (CBF) in awake adults using blood oxygenation level-dependent (BOLD) and pseudo-continuous arterial spin labeling (pCASL) MRI. Twelve healthy adults had BOLD and CBF responses measured to alterations in ET CO2 and O2 in various combinations commonly observed during anesthesia. Results Dynamic alterations in regional BOLD and CBF were seen in all subjects with expected and inverse brain voxel responses to both stimuli. These effects were incremental and rapid (within seconds). The most dramatic effects were seen with combined hyperoxia and hypocapnia. Inverse responses increased with age suggesting greater risk. Conclusions Human CBF responds dramatically to alterations in ET gas tensions commonly seen during anesthesia and in critical care. Such alterations may contribute to delirium following surgery and under certain circumstances in the critical care environment. Trial registration ClincialTrials.gov NCT02126215 for some components of the study. First registered April 29, 2014.
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Affiliation(s)
- W Alan C Mutch
- Department of Anesthesiology, Perioperative and Pain Medicine, Max Rady College of Medicine, University of Manitoba, 2nd Floor, Harry Medovy House, 671 William Ave., Winnipeg, MB, R3E 0Z2, Canada. .,Canada North Concussion Network, .
| | - Renée El-Gabalawy
- Department of Anesthesiology, Perioperative and Pain Medicine, Max Rady College of Medicine, University of Manitoba, 2nd Floor, Harry Medovy House, 671 William Ave., Winnipeg, MB, R3E 0Z2, Canada.,Department of Clinical Health Psychology, University of Manitoba, Winnipeg, Canada
| | - Lawrence Ryner
- Canada North Concussion Network.,Department of Radiology, University of Manitoba, Winnipeg, Canada.,Department of Physics, University of Manitoba, Winnipeg, Canada
| | - Josep Puig
- Department of Radiology, University of Manitoba, Winnipeg, Canada
| | - Marco Essig
- Canada North Concussion Network.,Department of Radiology, University of Manitoba, Winnipeg, Canada
| | - Kayla Kilborn
- Department of Anesthesiology, Perioperative and Pain Medicine, Max Rady College of Medicine, University of Manitoba, 2nd Floor, Harry Medovy House, 671 William Ave., Winnipeg, MB, R3E 0Z2, Canada
| | - Kelsi Fidler
- Department of Anesthesiology, Perioperative and Pain Medicine, Max Rady College of Medicine, University of Manitoba, 2nd Floor, Harry Medovy House, 671 William Ave., Winnipeg, MB, R3E 0Z2, Canada
| | - M Ruth Graham
- Department of Anesthesiology, Perioperative and Pain Medicine, Max Rady College of Medicine, University of Manitoba, 2nd Floor, Harry Medovy House, 671 William Ave., Winnipeg, MB, R3E 0Z2, Canada.,Canada North Concussion Network
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23
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Peng SL, Yang HC, Chen CM, Shih CT. Short- and long-term reproducibility of BOLD signal change induced by breath-holding at 1.5 and 3 T. NMR IN BIOMEDICINE 2020; 33:e4195. [PMID: 31885110 DOI: 10.1002/nbm.4195] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 09/09/2019] [Accepted: 09/09/2019] [Indexed: 06/10/2023]
Abstract
Cerebrovascular reactivity (CVR) can give insight into the cerebrovascular function. CVR can be estimated by measuring a blood-oxygen-level-dependent (BOLD) response combined with breath-holding (BH). The reproducibility of this technique has been addressed and existing studies have focused on short-term reproducibility using a 3 T magnetic resonance imaging (MRI) system. However, little is known about the long-term reproducibility of this procedure and the corresponding reproducibility using a 1.5 T MRI system. Here, we systematically examined the short- and long-term reproducibility of BOLD responses to BH across field strengths. Nine subjects participated in three MRI sessions separated by 30 minutes (sessions 1 and 2: short term) and 68-92 days (sessions 1 and 3, long term) at both 1.5 and 3 T MRI. Our findings revealed that significant differences between field strengths were detected in the activated gray matter volume and BOLD signal change (both P < 0.001), with smaller magnitudes at 1.5 T. However, activation patterns were reproducible, independent of the time interval, brain region or field strength. All interscan coefficient of variation values were below the 33% fiducial limit, and the intraclass correlation coefficient values were above 0.4, which is usually considered the acceptability limit in functional studies. These findings suggest that the response of BOLD signal to BH for assessing CVR is reproducible over time at 1.5 and 3 T. This technique can be considered a tool for monitoring longitudinal changes in patients with cerebrovascular diseases, and its use should be encouraged for clinical 1.5 T MRI systems.
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Affiliation(s)
- Shin-Lei Peng
- Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung, Taiwan
| | - Hui-Chieh Yang
- Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung, Taiwan
| | - Chun-Ming Chen
- Department of Radiology, China Medical University Hospital, Taichung, Taiwan
| | - Cheng-Ting Shih
- Department of Medical Imaging and Radiological Sciences, Chung Shan Medical University, Taichung, Taiwan
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24
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Neurovascular unit dysregulation, white matter disease, and executive dysfunction: the shared triad of vascular cognitive impairment and Alzheimer disease. GeroScience 2020; 42:445-465. [PMID: 32002785 DOI: 10.1007/s11357-020-00164-6] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Accepted: 01/22/2020] [Indexed: 01/07/2023] Open
Abstract
Executive dysfunction is the most important predictor for loss of independence in dementia. As executive function involves the coordination of distributed cerebral functions, executive function requires healthy white matter. However, white matter is highly vulnerable to cerebrovascular insults, with executive dysfunction being a core feature of vascular cognitive impairment (VCI). At the same time, cerebrovascular pathology, white matter disease, and executive dysfunction are all increasingly recognized as features of Alzheimer disease (AD). Recent studies have characterized the crucial role of glial cells in the pathological changes observed in both VCI and AD. In comorbid VCI and AD, the glial cells of the neurovascular unit (NVU) emerge as important therapeutic targets for the preservation of white matter integrity and executive function. Our synthesis from current research identifies dysregulation of the NVU, white matter disease, and executive dysfunction as a fundamental triad that is common to both VCI and AD. Further study of this triad will be critical for advancing the prevention and management of dementia.
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25
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Duffin J, Hare GM, Fisher JA. A mathematical model of cerebral blood flow control in anaemia and hypoxia. J Physiol 2020; 598:717-730. [DOI: 10.1113/jp279237] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 12/02/2019] [Indexed: 12/21/2022] Open
Affiliation(s)
- James Duffin
- Departments of Anaesthesia and PhysiologyUniversity of Toronto Toronto Ontario Canada
- Thornhill Research Inc. Toronto Ontario Canada
| | - Gregory M.T Hare
- Departments of Anaesthesia and PhysiologyUniversity of Toronto Toronto Ontario Canada
- Department of AnesthesiaKeenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute of St Michael's HospitalUnity Health Toronto Toronto Ontario Canada
| | - Joseph A. Fisher
- Departments of Anaesthesia and PhysiologyUniversity of Toronto Toronto Ontario Canada
- Thornhill Research Inc. Toronto Ontario Canada
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26
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Stotesbury H, Kawadler JM, Hales PW, Saunders DE, Clark CA, Kirkham FJ. Vascular Instability and Neurological Morbidity in Sickle Cell Disease: An Integrative Framework. Front Neurol 2019; 10:871. [PMID: 31474929 PMCID: PMC6705232 DOI: 10.3389/fneur.2019.00871] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 07/26/2019] [Indexed: 12/20/2022] Open
Abstract
It is well-established that patients with sickle cell disease (SCD) are at substantial risk of neurological complications, including overt and silent stroke, microstructural injury, and cognitive difficulties. Yet the underlying mechanisms remain poorly understood, partly because findings have largely been considered in isolation. Here, we review mechanistic pathways for which there is accumulating evidence and propose an integrative systems-biology framework for understanding neurological risk. Drawing upon work from other vascular beds in SCD, as well as the wider stroke literature, we propose that macro-circulatory hyper-perfusion, regions of relative micro-circulatory hypo-perfusion, and an exhaustion of cerebral reserve mechanisms, together lead to a state of cerebral vascular instability. We suggest that in this state, tissue oxygen supply is fragile and easily perturbed by changes in clinical condition, with the potential for stroke and/or microstructural injury if metabolic demand exceeds tissue oxygenation. This framework brings together recent developments in the field, highlights outstanding questions, and offers a first step toward a linking pathophysiological explanation of neurological risk that may help inform future screening and treatment strategies.
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Affiliation(s)
- Hanne Stotesbury
- Developmental Neurosciences, UCL Great Ormond Institute of Child Health, London, United Kingdom
| | - Jamie M Kawadler
- Developmental Neurosciences, UCL Great Ormond Institute of Child Health, London, United Kingdom
| | - Patrick W Hales
- Developmental Neurosciences, UCL Great Ormond Institute of Child Health, London, United Kingdom
| | - Dawn E Saunders
- Developmental Neurosciences, UCL Great Ormond Institute of Child Health, London, United Kingdom.,Department of Radiology, Great Ormond Hospital, London, United Kingdom
| | - Christopher A Clark
- Developmental Neurosciences, UCL Great Ormond Institute of Child Health, London, United Kingdom
| | - Fenella J Kirkham
- Developmental Neurosciences, UCL Great Ormond Institute of Child Health, London, United Kingdom.,Clinical and Experimental Sciences, University of Southampton, Southampton, United Kingdom.,Department of Child Health, University Hospital Southampton, Southampton, United Kingdom.,Department of Paediatric Neurology, Kings College Hospital NHS Foundation Trust, London, United Kingdom
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27
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Atwi S, Shao H, Crane DE, da Costa L, Aviv RI, Mikulis DJ, Black SE, MacIntosh BJ. BOLD-based cerebrovascular reactivity vascular transfer function isolates amplitude and timing responses to better characterize cerebral small vessel disease. NMR IN BIOMEDICINE 2019; 32:e4064. [PMID: 30693582 DOI: 10.1002/nbm.4064] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 12/03/2018] [Accepted: 12/18/2018] [Indexed: 06/09/2023]
Abstract
Cerebrovascular reactivity (CVR) is a dynamic measure of the cerebral blood vessel response to vasoactive stimulus. Conventional CVR measures amplitude changes in the blood-oxygenation-level-dependent (BOLD) signal per unit change in end-tidal CO2 (PET CO2 ), effectively discarding potential timing information. This study proposes a deconvolution procedure to characterize CVR responses based on a vascular transfer function (VTF) that separates amplitude and timing CVR effects. We implemented the CVR-VTF to primarily evaluate normal-appearing white matter (WM) responses in those with a range of small vessel disease. Comparisons between simulations of PET CO2 input models revealed that boxcar and ramp hypercapnia paradigms had the lowest relative deconvolution error. We used a T2 * BOLD-MRI sequence on a 3 T MRI scanner, with a boxcar delivery model of CO2 , to test the CVR-VTF approach in 18 healthy adults and three white matter hyperintensity (WMH) groups: 20 adults with moderate WMH, 12 adults with severe WMH, and 10 adults with genetic WMH (CADASIL). A subset of participants performed a second CVR session at a one-year follow-up. Conventional CVR, area under the curve of VTF (VTF-AUC), and VTF time-to-peak (VTF-TTP) were assessed in WM and grey matter (GM) at baseline and one-year follow-up. WMH groups had lower WM VTF-AUC compared with the healthy group (p < 0.0001), whereas GM CVR did not differ between groups (p > 0.1). WM VTF-TTP of the healthy group was less than that in the moderate WMH group (p = 0.016). Baseline VTF-AUC was lower than follow-up VTF-AUC in WM (p = 0.013) and GM (p = 0.026). The intraclass correlation for VTF-AUC in WM was 0.39 and coefficient of repeatability was 0.08 [%BOLD/mm Hg]. This study assessed CVR timing and amplitude information without applying model assumptions to the CVR response; this approach may be useful in the development of robust clinical biomarkers of CSVD.
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Affiliation(s)
- Sarah Atwi
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, University of Toronto, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Han Shao
- Division of Engineering Science, Faculty of Applied Science and Engineering, University of Toronto, Toronto, ON, Canada
| | - David E Crane
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, University of Toronto, Toronto, ON, Canada
| | - Leodante da Costa
- Division of Neurosurgery, Department of Surgery, Sunnybrook Hospital, University of Toronto, Toronto, ON, Canada
- Hurvitz Brain Sciences Research Program, Sunnybrook Research Institute, Toronto, ON, Canada
| | - Richard I Aviv
- Hurvitz Brain Sciences Research Program, Sunnybrook Research Institute, Toronto, ON, Canada
- Department of Medical Imaging, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
| | - David J Mikulis
- Division of Neuroradiology, Joint Department of Medical Imaging, University Health Network, Toronto, Canada
- Department of Medical Imaging, University of Toronto, Toronto, Canada
| | - Sandra E Black
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, University of Toronto, Toronto, ON, Canada
- Hurvitz Brain Sciences Research Program, Sunnybrook Research Institute, Toronto, ON, Canada
- Rehabilitation Sciences Institute, University of Toronto, Toronto, ON, Canada
- Rotman Research Institute, Baycrest Centre, Toronto, ON, Canada
- Department of Medicine (Neurology), University of Toronto, Toronto, ON, Canada
| | - Bradley J MacIntosh
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, University of Toronto, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
- Hurvitz Brain Sciences Research Program, Sunnybrook Research Institute, Toronto, ON, Canada
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28
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Prokopiou PC, Pattinson KTS, Wise RG, Mitsis GD. Modeling of dynamic cerebrovascular reactivity to spontaneous and externally induced CO 2 fluctuations in the human brain using BOLD-fMRI. Neuroimage 2018; 186:533-548. [PMID: 30423427 DOI: 10.1016/j.neuroimage.2018.10.084] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 10/09/2018] [Accepted: 10/31/2018] [Indexed: 11/30/2022] Open
Abstract
In this work, we investigate the regional characteristics of the dynamic interactions between arterial CO2 and BOLD (dynamic cerebrovascular reactivity - dCVR) during normal breathing and hypercapnic, externally induced step CO2 challenges. To obtain dCVR curves at each voxel, we use a custom set of basis functions based on the Laguerre and gamma basis sets. This allows us to obtain robust dCVR estimates both in larger regions of interest (ROIs), as well as in individual voxels. We also implement classification schemes to identify brain regions with similar dCVR characteristics. Our results reveal considerable variability of dCVR across different brain regions, as well as during different experimental conditions (normal breathing and hypercapnic challenges), suggesting a differential response of cerebral vasculature to spontaneous CO2 fluctuations and larger, externally induced CO2 changes that are possibly associated with the underlying differences in mean arterial CO2 levels. The clustering results suggest that anatomically distinct brain regions are characterized by different dCVR curves that in some cases do not exhibit the standard, positive valued curves that have been previously reported. They also reveal a consistent set of dCVR cluster shapes for resting and forcing conditions, which exhibit different distribution patterns across brain voxels.
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Affiliation(s)
- Prokopis C Prokopiou
- Integrated Program in Neuroscience, McGill University, Montreal Neurological Institude, H3A 2B4, QC, Canada
| | - Kyle T S Pattinson
- Nuffield Department of Anaesthetics, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, UK
| | - Richard G Wise
- CUBRIC, School of Psychology, University of Cardiff, CF10 3AT, UK
| | - Georgios D Mitsis
- Department of Bioengineering, McGill Univesity, Montreal, QC, H3A 0C3, Canada; Integrated Program in Neuroscience, McGill University, Montreal Neurological Institude, H3A 2B4, QC, Canada.
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29
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Geurts LJ, Bhogal AA, Siero JCW, Luijten PR, Biessels GJ, Zwanenburg JJM. Vascular reactivity in small cerebral perforating arteries with 7 T phase contrast MRI - A proof of concept study. Neuroimage 2018; 172:470-477. [PMID: 29408324 PMCID: PMC5915583 DOI: 10.1016/j.neuroimage.2018.01.055] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 01/14/2018] [Accepted: 01/21/2018] [Indexed: 01/08/2023] Open
Abstract
Existing cerebrovascular reactivity (CVR) techniques assess flow reactivity in either the largest cerebral vessels or at the level of the parenchyma. We examined the ability of 2D phase contrast MRI at 7 T to measure CVR in small cerebral perforating arteries. Blood flow velocity in perforators was measured in 10 healthy volunteers (mean age 26 years) using a 7 T MR scanner, using phase contrast acquisitions in the semioval center (CSO), the basal ganglia (BG) and the middle cerebral artery (MCA). Changes in flow velocity in response to a hypercapnic breathing challenge were assessed, and expressed as the percentual increase of flow velocity as a function of the increase in end tidal partial pressure of CO2. The hypercapnic challenge increased (fit ± standard error) flow velocity by 0.7 ± 0.3%/mmHg in the CSO (P < 0.01). Moreover, the number of detected perforators (mean [range]) increased from 63 [27–88] to 108 [61–178] (P < 0.001). In the BG, the hypercapnic challenge increased flow velocity by 1.6 ± 0.5%/mmHg (P < 0.001), and the number of detected perforators increased from 48 [24–66] to 63 [32–91] (P < 0.01). The flow in the MCA increased by 5.2 ± 1.4%/mmHg (P < 0.01). Small vessel specific reactivity can now be measured in perforators of the CSO and BG, using 2D phase contrast at 7 T. We show that 2D phase contrast at 7T MRI is capable of measuring reactivity in small cerebral perforating arteries. Reactivity to hypercapnia was measured in perforating arteries of the semi-oval center and the basal ganglia. Both blood flow velocity and the number of detected perforating arteries increased during hypercapnia. The proposed method bridges the gap between current reactivity measurements in parenchyma and large arteries.
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Affiliation(s)
- Lennart J Geurts
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands.
| | - Alex A Bhogal
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jeroen C W Siero
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands; Spinoza Centre for Neuroimaging Amsterdam, Amsterdam, The Netherlands
| | - Peter R Luijten
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Geert Jan Biessels
- Department of Neurology and Neurosurgery, Brain Centre Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jaco J M Zwanenburg
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
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30
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Rane S, Koh N, Boord P, Madhyastha T, Askren MK, Jayadev S, Cholerton B, Larson E, Grabowski TJ. Quantitative cerebrovascular pathology in a community-based cohort of older adults. Neurobiol Aging 2018; 65:77-85. [PMID: 29452984 DOI: 10.1016/j.neurobiolaging.2018.01.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 01/08/2018] [Accepted: 01/09/2018] [Indexed: 02/07/2023]
Abstract
Cerebrovascular disease, especially small vessel pathology, is the leading comorbidity in degenerative disorders. We applied arterial spin labeling and cerebrovascular reserve (CVR) imaging to quantify small vessel disease and study its effect on cognitive symptoms in nondemented older adults from a community-based cohort. We evaluated baseline cerebral blood flow (CBF) using arterial spin labeling and percent signal change as a marker of CVR using blood-oxygen level-dependent imaging following a breath-hold stimulus. Measurements were performed in and near white matter hyperintensities, which are currently the standard to assess severity of vascular pathology. We show that similar to other studies (1) CBF and CVR are markedly reduced in the hyperintensities as well as in the tissue surrounding them, indicating susceptibility to infarction; (2) low CBF and CVR are significantly correlated with poor cognitive performance; and (3) in addition, compared to a 58.4% reduction in CBF, larger exhaustion (79.3%) of CVR was observed in the hyperintensities with a faster, nonlinear rate of decline. We conclude that CVR may be a more sensitive biomarker of small vessel disease than CBF.
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Affiliation(s)
- Swati Rane
- Radiology, University of Washington Medical Center, Seattle, WA, USA.
| | - Natalie Koh
- Radiology, University of Washington Medical Center, Seattle, WA, USA
| | - Peter Boord
- Radiology, University of Washington Medical Center, Seattle, WA, USA
| | - Tara Madhyastha
- Radiology, University of Washington Medical Center, Seattle, WA, USA
| | - Mary K Askren
- Radiology, University of Washington Medical Center, Seattle, WA, USA
| | - Suman Jayadev
- Radiology, University of Washington Medical Center, Seattle, WA, USA
| | - Brenna Cholerton
- Department of Pathology, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Eric Larson
- Group Health Research Institute, Seattle, WA, USA
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Ryan CM, Battisti-Charbonney A, Sobczyk O, Mikulis DJ, Duffin J, Fisher JA, Venkatraghavan L. Evaluation of Cerebrovascular Reactivity in Subjects with and without Obstructive Sleep Apnea. J Stroke Cerebrovasc Dis 2018; 27:162-168. [DOI: 10.1016/j.jstrokecerebrovasdis.2017.08.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 08/13/2017] [Indexed: 11/27/2022] Open
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Domínguez RO, Marschoff ER, Oudkerk LM, Neira LJ, Serra JA. Daily Living Activities and Cognition in Aged Patients: Effect of Acute Systemic Diseases and Stroke on Leukoaraiosis. Curr Aging Sci 2018; 11:133-139. [PMID: 30338749 PMCID: PMC6388423 DOI: 10.2174/1874609811666181019103642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 07/19/2018] [Accepted: 10/01/2018] [Indexed: 11/22/2022]
Abstract
BACKGROUND Acute Systemic Diseases (ASD) impact on extended leukoaraiosis (ExLA) have been seldom described. We study the deterioration in daily life activities (DLA) and cognition associated with ASD events compared with the well-described impacts of stroke in patients with leukoaraiosis (L-A). METHODS Cross-sectional surveys of aged adults from the emergency room after an acute event of ASD or stroke, hospitalized or receiving home care, were followed for one year. From 268 initial patients 206 were included in the study, all with moderate to severe L-A (Fazekas 2 and 3). The Clinical Deterioration Rating (CDR) and the modified Rankin scale with structured interview were obtained one week previous to admission and after 3 and 12 months of evolution. Comparisons were conducted within and between groups with nonparametric techniques. RESULTS We formed three groups of similar age, A: Inpatients with one Stroke, B: Inpatients with one ASD, and C: Outpatients with one ASD. A sudden deterioration in Rankin was evident in Group A, while in B and C impairment was progressive. Impairment in CDR was smooth in all groups while in Rankin it was always greater than in cognition (CDR). No differences were found in the associations between groups and risk factors, hypertension being the most frequent one. CONCLUSION ASD in ExL-A causes a worsening of DLA and cognition similar to that observed in ExL-A with concomitant stroke indicating the need, in ageing patients, of differential diagnosis in order to achieve the best possible treatment.
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Affiliation(s)
| | | | | | | | - Jorge A. Serra
- Address correspondence to this author at the National Council of Scientific and Technical Investigations (CONICET), School of Biochemistry and Pharmacy, Oxidative Stress Lab., Institute of Biochemistry and Molecular Medicine (IBIMOL), Junín 954, C1113AAD, CABA, Argentina;
Tel: 5411 5287-4260. E-mail:
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Abstract
Sex and gender, as biological and social factors, significantly influence health outcomes. Among the biological factors, sex differences in vascular physiology may be one specific mechanism contributing to the observed differences in clinical presentation, response to treatment, and clinical outcomes in several vascular disorders. This review focuses on the cerebrovascular bed and summarizes the existing literature on sex differences in cerebrovascular hemodynamics to highlight the knowledge deficit that exists in this domain. The available evidence is used to generate mechanistically plausible and testable hypotheses to underscore the unmet need in understanding sex-specific mechanisms as targets for more effective therapeutic and preventive strategies.
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Affiliation(s)
- Cristina Duque
- Division of Stroke and Neurocritical Care, Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois.,Department of Neurology, Coimbra University Hospital Center, Coimbra, Portugal
| | - Steven K Feske
- Division of Stroke, Department of Neurology, Brigham and Women's Hospital, Boston, Massachusetts
| | - Farzaneh A Sorond
- Division of Stroke and Neurocritical Care, Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
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Thrippleton MJ, Shi Y, Blair G, Hamilton I, Waiter G, Schwarzbauer C, Pernet C, Andrews PJD, Marshall I, Doubal F, Wardlaw JM. Cerebrovascular reactivity measurement in cerebral small vessel disease: Rationale and reproducibility of a protocol for MRI acquisition and image processing. Int J Stroke 2017; 13:195-206. [DOI: 10.1177/1747493017730740] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background Impaired autoregulation may contribute to the pathogenesis of cerebral small vessel disease. Reliable protocols for measuring microvascular reactivity are required to test this hypothesis and for providing secondary endpoints in clinical trials. Aims To develop and assess a protocol for acquisition and processing of cerebrovascular reactivity by MRI, in subcortical tissue of patients with small vessel disease and minor stroke. Methods We recruited 15 healthy volunteers, testing paradigms using 1- and 3-min 6% CO2 challenges with repeat scanning, and 15 patients with history of minor stroke. We developed a protocol to measure cerebrovascular reactivity and delay times, assessing tolerability and reproducibility in grey and white matter areas. Results The 3-min paradigm yielded more reproducible data than the 1-min paradigm (CV respectively: 7.9–15.4% and 11.7–70.2% for cerebrovascular reactivity in grey matter), and was less reproducible in white matter (16.1–24.4% and 27.5–141.0%). Tolerability was similar for the two paradigms, but mean cerebrovascular reactivity and cerebrovascular reactivity delay were significantly higher for the 3-min paradigm in most regions. Patient tolerability was high with no evidence of greater failure rate (1/15 patients vs. 2/15 volunteers withdrew at the first visit). Grey matter cerebrovascular reactivity was lower in patients than in volunteers (0.110–0.234 vs. 0.172–0.313%/mmHg; p < 0.05 in 6/8 regions), as was the white matter cerebrovascular reactivity delay (16.2–43.9 vs. 31.1–47.9 s; p < 0.05 in 4/8 regions). Conclusions An effective and well-tolerated protocol for measurement of cerebrovascular reactivity was developed for use in ongoing and future trials to investigate small vessel disease pathophysiology and to measure treatment effects.
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Affiliation(s)
- Michael J Thrippleton
- Neuroimaging Sciences, University of Edinburgh, Edinburgh, UK
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Yulu Shi
- Neuroimaging Sciences, University of Edinburgh, Edinburgh, UK
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Gordon Blair
- Neuroimaging Sciences, University of Edinburgh, Edinburgh, UK
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Iona Hamilton
- Neuroimaging Sciences, University of Edinburgh, Edinburgh, UK
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Gordon Waiter
- Aberdeen Biomedical Imaging Centre, University of Aberdeen, Aberdeen, UK
| | - Christian Schwarzbauer
- Faculty of Applied Sciences & Mechatronics, Munich University of Applied Sciences, Munich, Germany
| | - Cyril Pernet
- Neuroimaging Sciences, University of Edinburgh, Edinburgh, UK
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Peter JD Andrews
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Ian Marshall
- Neuroimaging Sciences, University of Edinburgh, Edinburgh, UK
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Fergus Doubal
- Neuroimaging Sciences, University of Edinburgh, Edinburgh, UK
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Joanna M Wardlaw
- Neuroimaging Sciences, University of Edinburgh, Edinburgh, UK
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
- UK Dementia Research Institute at the University of Edinburgh
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Prokopiou PC, Murphy K, Wise RG, Mitsis GD. Estimation of voxel-wise dynamic cerebrovascular reactivity curves from resting-state fMRI data. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2017; 2016:1143-1146. [PMID: 28268528 DOI: 10.1109/embc.2016.7590906] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In this work, we investigate the linear dynamic interactions between fluctuations in arterial CO2 that occur during normal breathing, and the BOLD fMRI signal. We cast this problem within a systems-theoretic framework, where we employ functional expansions for the estimation of the impulse responses in large regions of interest, as well as in individual voxels. We also implement classification schemes in order to identify different brain regions with similar cerebrovascular reactivity characteristics. Our results reveal that it is feasible to obtain reliable estimates of cerebrovascular reactivity curves from resting-state data and that these curves exhibit considerable variability across different brain regions that may be related to the underlying anatomy.
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Fisher JA, Sobczyk O, Crawley A, Poublanc J, Dufort P, Venkatraghavan L, Sam K, Mikulis D, Duffin J. Assessing cerebrovascular reactivity by the pattern of response to progressive hypercapnia. Hum Brain Mapp 2017; 38:3415-3427. [PMID: 28370825 DOI: 10.1002/hbm.23598] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 03/02/2017] [Accepted: 03/22/2017] [Indexed: 11/10/2022] Open
Abstract
Cerebral blood flow responds to a carbon dioxide challenge, and is often assessed as cerebrovascular reactivity, assuming a linear response over a limited stimulus range or a sigmoidal response over a wider range. However, these assumed response patterns may not necessarily apply to regions with pathophysiology. Deviations from sigmoidal responses are hypothesised to result from upstream flow limitations causing competition for blood flow between downstream regions, particularly with vasodilatory stimulation; flow is preferentially distributed to regions with more reactive vessels. Under these conditions, linear or sigmoidal fitting may not fairly describe the relationship between stimulus and flow. To assess the range of response patterns and their prevalence a survey of healthy control subjects and patients with cerebrovascular disease was conducted. We used a ramp carbon dioxide challenge from hypo- to hypercapnia as the stimulus, and magnetic resonance imaging to measure the flow responses. We categorized BOLD response patterns into four types based on the signs of their linear slopes in the hypo- and hypercapnic ranges, color coded and mapped them onto their respective anatomical scans. We suggest that these type maps complement maps of linear cerebrovascular reactivity by providing a better indication of the actual response patterns. Hum Brain Mapp 38:3415-3427, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Joseph A Fisher
- Department of Physiology, University of Toronto, Toronto, Canada.,Institute of Medical Science, University of Toronto, Toronto, Canada.,Department of Anaesthesia and Pain Management, University Health Network, University of Toronto, Toronto, Canada
| | - Olivia Sobczyk
- Institute of Medical Science, University of Toronto, Toronto, Canada
| | - Adrian Crawley
- Joint Department of Medical Imaging and the Functional Neuroimaging Laboratory, University Health Network, Toronto, Canada
| | - Julien Poublanc
- Joint Department of Medical Imaging and the Functional Neuroimaging Laboratory, University Health Network, Toronto, Canada
| | - Paul Dufort
- Joint Department of Medical Imaging and the Functional Neuroimaging Laboratory, University Health Network, Toronto, Canada
| | - Lashmi Venkatraghavan
- Department of Anaesthesia and Pain Management, University Health Network, University of Toronto, Toronto, Canada
| | - Kevin Sam
- Joint Department of Medical Imaging and the Functional Neuroimaging Laboratory, University Health Network, Toronto, Canada
| | - David Mikulis
- Institute of Medical Science, University of Toronto, Toronto, Canada.,Joint Department of Medical Imaging and the Functional Neuroimaging Laboratory, University Health Network, Toronto, Canada
| | - James Duffin
- Department of Physiology, University of Toronto, Toronto, Canada.,Department of Anaesthesia and Pain Management, University Health Network, University of Toronto, Toronto, Canada
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Yang T, Sun Y, Lu Z, Leak RK, Zhang F. The impact of cerebrovascular aging on vascular cognitive impairment and dementia. Ageing Res Rev 2017; 34:15-29. [PMID: 27693240 DOI: 10.1016/j.arr.2016.09.007] [Citation(s) in RCA: 114] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 08/09/2016] [Accepted: 09/26/2016] [Indexed: 02/07/2023]
Abstract
As human life expectancy rises, the aged population will increase. Aging is accompanied by changes in tissue structure, often resulting in functional decline. For example, aging within blood vessels contributes to a decrease in blood flow to important organs, potentially leading to organ atrophy and loss of function. In the central nervous system, cerebral vascular aging can lead to loss of the integrity of the blood-brain barrier, eventually resulting in cognitive and sensorimotor decline. One of the major of types of cognitive dysfunction due to chronic cerebral hypoperfusion is vascular cognitive impairment and dementia (VCID). In spite of recent progress in clinical and experimental VCID research, our understanding of vascular contributions to the pathogenesis of VCID is still very limited. In this review, we summarize recent findings on VCID, with a focus on vascular age-related pathologies and their contribution to the development of this condition.
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Affiliation(s)
- Tuo Yang
- Department of Neurology, Pittsburgh Institute of Brain Disorders and Recovery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Yang Sun
- Department of Neurology, Pittsburgh Institute of Brain Disorders and Recovery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Zhengyu Lu
- Department of Neurology, Pittsburgh Institute of Brain Disorders and Recovery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Department of Neurology, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese, Shanghai 200437, China
| | - Rehana K Leak
- Division of Pharmaceutical Sciences, Mylan School of Pharmacy, Duquesne University, Pittsburgh, PA 15282, USA
| | - Feng Zhang
- Department of Neurology, Pittsburgh Institute of Brain Disorders and Recovery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Key Lab of Cerebral Microcirculation in Universities of Shandong, Taishan Medical University, Taian, Shandong, 271000, China.
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38
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Sam K, Peltenburg B, Conklin J, Sobczyk O, Poublanc J, Crawley AP, Mandell DM, Venkatraghavan L, Duffin J, Fisher JA, Black SE, Mikulis DJ. Cerebrovascular reactivity and white matter integrity. Neurology 2016; 87:2333-2339. [PMID: 27794113 DOI: 10.1212/wnl.0000000000003373] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 08/24/2016] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To compare the diffusion and perfusion MRI metrics of normal-appearing white matter (NAWM) with and without impaired cerebrovascular reactivity (CVR). METHODS Seventy-five participants with moderate to severe leukoaraiosis underwent blood oxygen level-dependent CVR mapping using a 3T MRI system with precise carbon dioxide stimulus manipulation. Several MRI metrics were statistically compared between areas of NAWM with positive and negative CVR using one-way analysis of variance with Bonferroni correction for multiple comparisons. RESULTS Areas of NAWM with negative CVR showed a significant reduction in fractional anisotropy by a mean (SD) of 3.7% (2.4), cerebral blood flow by 22.1% (8.2), regional cerebral blood volume by 22.2% (7.0), and a significant increase in mean diffusivity by 3.9% (3.1) and time to maximum by 10.9% (13.2) (p < 0.01), compared to areas with positive CVR. CONCLUSIONS Impaired CVR is associated with subtle changes in the tissue integrity of NAWM, as evaluated using several quantitative diffusion and perfusion MRI metrics. These findings suggest that impaired CVR may contribute to the progression of white matter disease.
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Affiliation(s)
- Kevin Sam
- From the Department of Physiology (K.S., J.D., J.A.F.), Division of Neuroradiology, Joint Department of Medical Imaging, Toronto Western Hospital (K.S., J.C., O.S., J.P., A.P.C., D.M.M., D.J.M.), Department of Medical Imaging (A.P.C., D.M.M., D.J.M.), and Department of Anaesthesia, Toronto General Hospital (L.V., J.D., J.A.F.), The University of Toronto, Canada; Department of Radiotherapy (B.P.), Imaging Division, University Medical Center Utrecht, Utrecht University, the Netherlands; and L.C. Campbell Cognitive Neurology Research Unit (S.E.B.), Sunnybrook Health Sciences Centre, Toronto, Canada
| | - Boris Peltenburg
- From the Department of Physiology (K.S., J.D., J.A.F.), Division of Neuroradiology, Joint Department of Medical Imaging, Toronto Western Hospital (K.S., J.C., O.S., J.P., A.P.C., D.M.M., D.J.M.), Department of Medical Imaging (A.P.C., D.M.M., D.J.M.), and Department of Anaesthesia, Toronto General Hospital (L.V., J.D., J.A.F.), The University of Toronto, Canada; Department of Radiotherapy (B.P.), Imaging Division, University Medical Center Utrecht, Utrecht University, the Netherlands; and L.C. Campbell Cognitive Neurology Research Unit (S.E.B.), Sunnybrook Health Sciences Centre, Toronto, Canada
| | - John Conklin
- From the Department of Physiology (K.S., J.D., J.A.F.), Division of Neuroradiology, Joint Department of Medical Imaging, Toronto Western Hospital (K.S., J.C., O.S., J.P., A.P.C., D.M.M., D.J.M.), Department of Medical Imaging (A.P.C., D.M.M., D.J.M.), and Department of Anaesthesia, Toronto General Hospital (L.V., J.D., J.A.F.), The University of Toronto, Canada; Department of Radiotherapy (B.P.), Imaging Division, University Medical Center Utrecht, Utrecht University, the Netherlands; and L.C. Campbell Cognitive Neurology Research Unit (S.E.B.), Sunnybrook Health Sciences Centre, Toronto, Canada
| | - Olivia Sobczyk
- From the Department of Physiology (K.S., J.D., J.A.F.), Division of Neuroradiology, Joint Department of Medical Imaging, Toronto Western Hospital (K.S., J.C., O.S., J.P., A.P.C., D.M.M., D.J.M.), Department of Medical Imaging (A.P.C., D.M.M., D.J.M.), and Department of Anaesthesia, Toronto General Hospital (L.V., J.D., J.A.F.), The University of Toronto, Canada; Department of Radiotherapy (B.P.), Imaging Division, University Medical Center Utrecht, Utrecht University, the Netherlands; and L.C. Campbell Cognitive Neurology Research Unit (S.E.B.), Sunnybrook Health Sciences Centre, Toronto, Canada
| | - Julien Poublanc
- From the Department of Physiology (K.S., J.D., J.A.F.), Division of Neuroradiology, Joint Department of Medical Imaging, Toronto Western Hospital (K.S., J.C., O.S., J.P., A.P.C., D.M.M., D.J.M.), Department of Medical Imaging (A.P.C., D.M.M., D.J.M.), and Department of Anaesthesia, Toronto General Hospital (L.V., J.D., J.A.F.), The University of Toronto, Canada; Department of Radiotherapy (B.P.), Imaging Division, University Medical Center Utrecht, Utrecht University, the Netherlands; and L.C. Campbell Cognitive Neurology Research Unit (S.E.B.), Sunnybrook Health Sciences Centre, Toronto, Canada
| | - Adrian P Crawley
- From the Department of Physiology (K.S., J.D., J.A.F.), Division of Neuroradiology, Joint Department of Medical Imaging, Toronto Western Hospital (K.S., J.C., O.S., J.P., A.P.C., D.M.M., D.J.M.), Department of Medical Imaging (A.P.C., D.M.M., D.J.M.), and Department of Anaesthesia, Toronto General Hospital (L.V., J.D., J.A.F.), The University of Toronto, Canada; Department of Radiotherapy (B.P.), Imaging Division, University Medical Center Utrecht, Utrecht University, the Netherlands; and L.C. Campbell Cognitive Neurology Research Unit (S.E.B.), Sunnybrook Health Sciences Centre, Toronto, Canada
| | - Daniel M Mandell
- From the Department of Physiology (K.S., J.D., J.A.F.), Division of Neuroradiology, Joint Department of Medical Imaging, Toronto Western Hospital (K.S., J.C., O.S., J.P., A.P.C., D.M.M., D.J.M.), Department of Medical Imaging (A.P.C., D.M.M., D.J.M.), and Department of Anaesthesia, Toronto General Hospital (L.V., J.D., J.A.F.), The University of Toronto, Canada; Department of Radiotherapy (B.P.), Imaging Division, University Medical Center Utrecht, Utrecht University, the Netherlands; and L.C. Campbell Cognitive Neurology Research Unit (S.E.B.), Sunnybrook Health Sciences Centre, Toronto, Canada
| | - Lakshmikumar Venkatraghavan
- From the Department of Physiology (K.S., J.D., J.A.F.), Division of Neuroradiology, Joint Department of Medical Imaging, Toronto Western Hospital (K.S., J.C., O.S., J.P., A.P.C., D.M.M., D.J.M.), Department of Medical Imaging (A.P.C., D.M.M., D.J.M.), and Department of Anaesthesia, Toronto General Hospital (L.V., J.D., J.A.F.), The University of Toronto, Canada; Department of Radiotherapy (B.P.), Imaging Division, University Medical Center Utrecht, Utrecht University, the Netherlands; and L.C. Campbell Cognitive Neurology Research Unit (S.E.B.), Sunnybrook Health Sciences Centre, Toronto, Canada
| | - James Duffin
- From the Department of Physiology (K.S., J.D., J.A.F.), Division of Neuroradiology, Joint Department of Medical Imaging, Toronto Western Hospital (K.S., J.C., O.S., J.P., A.P.C., D.M.M., D.J.M.), Department of Medical Imaging (A.P.C., D.M.M., D.J.M.), and Department of Anaesthesia, Toronto General Hospital (L.V., J.D., J.A.F.), The University of Toronto, Canada; Department of Radiotherapy (B.P.), Imaging Division, University Medical Center Utrecht, Utrecht University, the Netherlands; and L.C. Campbell Cognitive Neurology Research Unit (S.E.B.), Sunnybrook Health Sciences Centre, Toronto, Canada
| | - Joseph A Fisher
- From the Department of Physiology (K.S., J.D., J.A.F.), Division of Neuroradiology, Joint Department of Medical Imaging, Toronto Western Hospital (K.S., J.C., O.S., J.P., A.P.C., D.M.M., D.J.M.), Department of Medical Imaging (A.P.C., D.M.M., D.J.M.), and Department of Anaesthesia, Toronto General Hospital (L.V., J.D., J.A.F.), The University of Toronto, Canada; Department of Radiotherapy (B.P.), Imaging Division, University Medical Center Utrecht, Utrecht University, the Netherlands; and L.C. Campbell Cognitive Neurology Research Unit (S.E.B.), Sunnybrook Health Sciences Centre, Toronto, Canada
| | - Sandra E Black
- From the Department of Physiology (K.S., J.D., J.A.F.), Division of Neuroradiology, Joint Department of Medical Imaging, Toronto Western Hospital (K.S., J.C., O.S., J.P., A.P.C., D.M.M., D.J.M.), Department of Medical Imaging (A.P.C., D.M.M., D.J.M.), and Department of Anaesthesia, Toronto General Hospital (L.V., J.D., J.A.F.), The University of Toronto, Canada; Department of Radiotherapy (B.P.), Imaging Division, University Medical Center Utrecht, Utrecht University, the Netherlands; and L.C. Campbell Cognitive Neurology Research Unit (S.E.B.), Sunnybrook Health Sciences Centre, Toronto, Canada
| | - David J Mikulis
- From the Department of Physiology (K.S., J.D., J.A.F.), Division of Neuroradiology, Joint Department of Medical Imaging, Toronto Western Hospital (K.S., J.C., O.S., J.P., A.P.C., D.M.M., D.J.M.), Department of Medical Imaging (A.P.C., D.M.M., D.J.M.), and Department of Anaesthesia, Toronto General Hospital (L.V., J.D., J.A.F.), The University of Toronto, Canada; Department of Radiotherapy (B.P.), Imaging Division, University Medical Center Utrecht, Utrecht University, the Netherlands; and L.C. Campbell Cognitive Neurology Research Unit (S.E.B.), Sunnybrook Health Sciences Centre, Toronto, Canada.
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Sam K, Crawley AP, Conklin J, Poublanc J, Sobczyk O, Mandell DM, Venkatraghavan L, Duffin J, Fisher JA, Black SE, Mikulis DJ. Development of White Matter Hyperintensity Is Preceded by Reduced Cerebrovascular Reactivity. Ann Neurol 2016; 80:277-85. [DOI: 10.1002/ana.24712] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 06/06/2016] [Accepted: 06/26/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Kevin Sam
- Department of Physiology; University of Toronto; Toronto Ontario Canada
- Division of Neuroradiology, Joint Department of Medical Imaging; University Health Network; Toronto Ontario Canada
| | - Adrian P. Crawley
- Division of Neuroradiology, Joint Department of Medical Imaging; University Health Network; Toronto Ontario Canada
- Department of Medical Imaging; University of Toronto; Toronto Ontario Canada
- Institute of Medical Sciences; University of Toronto; Toronto Ontario Canada
| | - John Conklin
- Division of Neuroradiology, Joint Department of Medical Imaging; University Health Network; Toronto Ontario Canada
| | - Julien Poublanc
- Division of Neuroradiology, Joint Department of Medical Imaging; University Health Network; Toronto Ontario Canada
| | - Olivia Sobczyk
- Division of Neuroradiology, Joint Department of Medical Imaging; University Health Network; Toronto Ontario Canada
- Institute of Medical Sciences; University of Toronto; Toronto Ontario Canada
| | - Daniel M. Mandell
- Division of Neuroradiology, Joint Department of Medical Imaging; University Health Network; Toronto Ontario Canada
- Institute of Medical Sciences; University of Toronto; Toronto Ontario Canada
| | | | - James Duffin
- Department of Physiology; University of Toronto; Toronto Ontario Canada
- Department of Anesthesiology; University Health Network; Toronto Ontario Canada
| | - Joseph A. Fisher
- Department of Physiology; University of Toronto; Toronto Ontario Canada
- Institute of Medical Sciences; University of Toronto; Toronto Ontario Canada
- Department of Anesthesiology; University Health Network; Toronto Ontario Canada
| | - Sandra E. Black
- Institute of Medical Sciences; University of Toronto; Toronto Ontario Canada
- LC Campbell Cognitive Neurology Research Unit; Sunnybrook Health Sciences Centre; Toronto Ontario Canada
| | - David J. Mikulis
- Division of Neuroradiology, Joint Department of Medical Imaging; University Health Network; Toronto Ontario Canada
- Department of Medical Imaging; University of Toronto; Toronto Ontario Canada
- Institute of Medical Sciences; University of Toronto; Toronto Ontario Canada
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Sam K, Crawley AP, Poublanc J, Conklin J, Sobczyk O, Mandell DM, Duffin J, Venkatraghavan L, Fisher JA, Black SE, Mikulis DJ. Vascular Dysfunction in Leukoaraiosis. AJNR Am J Neuroradiol 2016; 37:2258-2264. [PMID: 27492072 DOI: 10.3174/ajnr.a4888] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 06/07/2016] [Indexed: 01/04/2023]
Abstract
BACKGROUND AND PURPOSE The pathogenesis of leukoaraiosis has long been debated. This work addresses a less well-studied mechanism, cerebrovascular reactivity, which could play a leading role in the pathogenesis of this disease. Our aim was to evaluate blood flow dysregulation and its relation to leukoaraiosis. MATERIALS AND METHODS Cerebrovascular reactivity, the change in the blood oxygen level-dependent 3T MR imaging signal in response to a consistently applied step change in the arterial partial pressure of carbon dioxide, was measured in white matter hyperintensities and their contralateral spatially homologous normal-appearing white matter in 75 older subjects (age range, 50-91 years; 40 men) with leukoaraiosis. Additional quantitative evaluation of regions of leukoaraiosis was performed by using diffusion (n = 75), quantitative T2 (n = 54), and DSC perfusion MRI metrics (n = 25). RESULTS When we compared white matter hyperintensities with contralateral normal-appearing white matter, cerebrovascular reactivity was lower by a mean of 61.2% ± 22.6%, fractional anisotropy was lower by 44.9 % ± 6.9%, and CBF was lower by 10.9% ± 11.9%. T2 was higher by 61.7% ± 13.5%, mean diffusivity was higher by 59.0% ± 11.7%, time-to-maximum was higher by 44.4% ± 30.4%, and TTP was higher by 6.8% ± 5.8% (all P < .01). Cerebral blood volume was lower in white matter hyperintensities compared with contralateral normal-appearing white matter by 10.2% ± 15.0% (P = .03). CONCLUSIONS Not only were resting blood flow metrics abnormal in leukoaraiosis but there is also evidence of reduced cerebrovascular reactivity in these areas. Studies have shown that reduced cerebrovascular reactivity is more sensitive than resting blood flow parameters for assessing vascular insufficiency. Future work is needed to examine the sensitivity of resting-versus-dynamic blood flow measures for investigating the pathogenesis of leukoaraiosis.
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Affiliation(s)
- K Sam
- From the Departments of Physiology (K.S., J.D., J.A.F.).,Division of Neuroradiology (K.S., A.P.C., J.P., J.C., O.S., D.M.M., D.J.M.), Joint Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada
| | - A P Crawley
- Medical Imaging (A.P.C., D.J.M.), University of Toronto, Toronto, Ontario, Canada.,Division of Neuroradiology (K.S., A.P.C., J.P., J.C., O.S., D.M.M., D.J.M.), Joint Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada
| | - J Poublanc
- Division of Neuroradiology (K.S., A.P.C., J.P., J.C., O.S., D.M.M., D.J.M.), Joint Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada
| | - J Conklin
- Division of Neuroradiology (K.S., A.P.C., J.P., J.C., O.S., D.M.M., D.J.M.), Joint Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada
| | - O Sobczyk
- Division of Neuroradiology (K.S., A.P.C., J.P., J.C., O.S., D.M.M., D.J.M.), Joint Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada
| | - D M Mandell
- Division of Neuroradiology (K.S., A.P.C., J.P., J.C., O.S., D.M.M., D.J.M.), Joint Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada
| | - J Duffin
- From the Departments of Physiology (K.S., J.D., J.A.F.).,Department of Anesthesiology (J.D., L.V., J.A.F.), University Health Network and The University of Toronto, Toronto, Ontario, Canada
| | - L Venkatraghavan
- Department of Anesthesiology (J.D., L.V., J.A.F.), University Health Network and The University of Toronto, Toronto, Ontario, Canada
| | - J A Fisher
- From the Departments of Physiology (K.S., J.D., J.A.F.).,Department of Anesthesiology (J.D., L.V., J.A.F.), University Health Network and The University of Toronto, Toronto, Ontario, Canada
| | - S E Black
- L.C. Campbell Cognitive Neurology Research Unit (S.E.B.), Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
| | - D J Mikulis
- Medical Imaging (A.P.C., D.J.M.), University of Toronto, Toronto, Ontario, Canada .,Division of Neuroradiology (K.S., A.P.C., J.P., J.C., O.S., D.M.M., D.J.M.), Joint Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada
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Mikhail Kellawan J, Harrell JW, Schrauben EM, Hoffman CA, Roldan-Alzate A, Schrage WG, Wieben O. Quantitative cerebrovascular 4D flow MRI at rest and during hypercapnia challenge. Magn Reson Imaging 2016; 34:422-8. [DOI: 10.1016/j.mri.2015.12.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 12/13/2015] [Indexed: 12/01/2022]
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Jeong SM, Kim SO, DeLorey DS, Babb TG, Levine BD, Zhang R. Lack of correlation between cerebral vasomotor reactivity and dynamic cerebral autoregulation during stepwise increases in inspired CO2 concentration. J Appl Physiol (1985) 2016; 120:1434-41. [PMID: 27103653 DOI: 10.1152/japplphysiol.00390.2015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 04/18/2016] [Indexed: 11/22/2022] Open
Abstract
Cerebral vasomotor reactivity (CVMR) and dynamic cerebral autoregulation (CA) are measured extensively in clinical and research studies. However, the relationship between these measurements of cerebrovascular function is not well understood. In this study, we measured changes in cerebral blood flow velocity (CBFV) and arterial blood pressure (BP) in response to stepwise increases in inspired CO2 concentrations of 3 and 6% to assess CVMR and dynamic CA in 13 healthy young adults [2 women, 32 ± 9 (SD) yr]. CVMR was assessed as percentage changes in CBFV (CVMRCBFV) or cerebrovascular conductance index (CVCi, CVMRCVCi) in response to hypercapnia. Dynamic CA was estimated by performing transfer function analysis between spontaneous oscillations in BP and CBFV. Steady-state CBFV and CVCi both increased exponentially during hypercapnia; CVMRCBFV and CVMRCVCi were greater at 6% (3.85 ± 0.90 and 2.45 ± 0.79%/mmHg) than at 3% CO2 (2.09 ± 1.47 and 0.21 ± 1.56%/mmHg, P = 0.009 and 0.005, respectively). Furthermore, CVMRCBFV was greater than CVMRCVCi during either 3 or 6% CO2 (P = 0.017 and P < 0.001, respectively). Transfer function gain and coherence increased in the very low frequency range (0.02-0.07 Hz), and phase decreased in the low-frequency range (0.07-0.20 Hz) when breathing 6%, but not 3% CO2 There were no correlations between the measurements of CVMR and dynamic CA. These findings demonstrated influences of inspired CO2 concentrations on assessment of CVMR and dynamic CA. The lack of correlation between CVMR and dynamic CA suggests that cerebrovascular responses to changes in arterial CO2 and BP are mediated by distinct regulatory mechanisms.
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Affiliation(s)
- Sung-Moon Jeong
- Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas and University of Texas Southwestern Medical Center, Dallas, Texas; Department of Anesthesiology and Pain Medicine, College of Medicine, University of Ulsan, Asan Medical Center, Seoul, Korea
| | - Seon-Ok Kim
- Department of Clinical Epidemiology and Biostatistics, College of Medicine, University of Ulsan, Asan Medical Center, Seoul, Korea; and
| | - Darren S DeLorey
- Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Tony G Babb
- Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas and University of Texas Southwestern Medical Center, Dallas, Texas
| | - Benjamin D Levine
- Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas and University of Texas Southwestern Medical Center, Dallas, Texas
| | - Rong Zhang
- Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas and University of Texas Southwestern Medical Center, Dallas, Texas;
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43
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Foster GE, Davies-Thompson J, Dominelli PB, Heran MKS, Donnelly J, duManoir GR, Ainslie PN, Rauscher A, Sheel AW. Changes in cerebral vascular reactivity and structure following prolonged exposure to high altitude in humans. Physiol Rep 2015; 3:3/12/e12647. [PMID: 26660556 PMCID: PMC4760444 DOI: 10.14814/phy2.12647] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Although high‐altitude exposure can lead to neurocognitive impairment, even upon return to sea level, it remains unclear the extent to which brain volume and regional cerebral vascular reactivity (CVR) are altered following high‐altitude exposure. The purpose of this study was to simultaneously determine the effect of 3 weeks at 5050 m on: (1) structural brain alterations; and (2) regional CVR after returning to sea level for 1 week. Healthy human volunteers (n = 6) underwent baseline and follow‐up structural and functional magnetic resonance imaging (MRI) at rest and during a CVR protocol (end‐tidal PCO2 reduced by −10, −5 and increased by +5, +10, and +15 mmHg from baseline). CVR maps (% mmHg−1) were generated using BOLD MRI and brain volumes were estimated. Following return to sea level, whole‐brain volume and gray matter volume was reduced by 0.4 ± 0.3% (P < 0.01) and 2.6 ± 1.0% (P < 0.001), respectively; white matter was unchanged. Global gray matter CVR and white matter CVR were unchanged following return to sea level, but CVR was selectively increased (P < 0.05) in the brainstem (+30 ± 12%), hippocampus (+12 ± 3%), and thalamus (+10 ± 3%). These changes were the result of improvement and/or reversal of negative CVR to positive CVR in these regions. Three weeks of high‐altitude exposure is reflected in loss of gray matter volume and improvements in negative CVR.
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Affiliation(s)
- Glen E Foster
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada School of Kinesiology, University of British Columbia, Vancouver, Canada
| | - Jodie Davies-Thompson
- Department of Ophthalmology and Visual Sciences, Faculty of Medicine, University of British Columbia, Vancouver, Canada
| | - Paolo B Dominelli
- School of Kinesiology, University of British Columbia, Vancouver, Canada
| | - Manraj K S Heran
- Diagnostic and Therapeutic Neuroradiology, Vancouver General Hospital University of British Columbia, Vancouver, Canada
| | - Joseph Donnelly
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Gregory R duManoir
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada
| | - Philip N Ainslie
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada
| | - Alexander Rauscher
- Department of Radiology, UBC MRI Research Centre University of British Columbia, Vancouver, Canada
| | - A William Sheel
- School of Kinesiology, University of British Columbia, Vancouver, Canada
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Bohr I, McDonald C, He J, Kerr S, Newton JL, Blamire AM. Brain oxygenation responses to an autonomic challenge: a quantitative fMRI investigation of the Valsalva manoeuvre. AGE (DORDRECHT, NETHERLANDS) 2015; 37:91. [PMID: 26318855 PMCID: PMC5005835 DOI: 10.1007/s11357-015-9833-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 08/20/2015] [Indexed: 06/04/2023]
Abstract
In late age, the autonomic nervous system (ANS) has diminished ability to maintain physiological homeostasis in the brain in response to challenges such as to systemic blood pressure changes caused by standing. We devised an fMRI experiment aiming to map the cerebral effects of an ANS challenge (Valsalva manoeuvre (VM)). We used dual-echo fMRI to measure the effective transverse relaxation rate (R2*, which is inversely proportional to brain tissue oxygenation levels) in 45 elderly subjects (median age 80 years old, total range 75-89) during performance of the VM. In addition, we collected fluid-attenuated inversion recovery (FLAIR) data from which we quantified white matter hyperintensity (WMH) volumes. We conducted voxelwise analysis of the dynamic changes in R2* during the VM to determine the distribution of oxygenation changes due to the autonomic stressor. In white matter, we observed significant decreases in oxygenation levels. These effects were predominantly located in posterior white matter and to a lesser degree in the right anterior brain, both concentrated around the border zones (watersheds) between cerebral perfusion territories. These areas are known to be particularly vulnerable to hypoxia and are prone to formation of white matter hyperintensities. Although we observed overlap between localisation of WMH and triggered deoxygenation on the group level, we did not find significant association between these independent variables using subjectwise statistics. This could suggest other than recurrent transient hypoxia mechanisms causing/contributing to the formation of WMH.
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Affiliation(s)
- Iwo Bohr
- Institute of Cellular Medicine and Newcastle Magnetic Resonance Centre, Campus for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, NE4 5PL, UK,
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Ravi H, Thomas BP, Peng SL, Liu H, Lu H. On the optimization of imaging protocol for the mapping of cerebrovascular reactivity. J Magn Reson Imaging 2015; 43:661-8. [PMID: 26268541 DOI: 10.1002/jmri.25028] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Revised: 07/23/2015] [Accepted: 07/24/2015] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND To devise an improved blood-oxygen-level-dependent (BOLD) imaging protocol for cerebrovascular reactivity (CVR) measurement that can remove a known artifact of negative values. METHODS Theoretical and simulation studies were first performed to understand the biophysical mechanism of the negative CVR signals, through which improved BOLD sequence parameters were proposed. This was achieved by equating signal intensities between cerebrospinal fluid and blood, by means of shortening the echo time (TE) of the BOLD sequence. Then, 10 healthy volunteers were recruited to participate in an experimental study, in which we compared the CVR results of two versions of the optimized ("Opt1" and "Opt2") protocols with that of the standard protocol at 3 Tesla. Two sessions were performed for each subject to test the reproducibility of all three protocols. RESULTS Experimental results demonstrated that the optimized protocols resulted in elimination of negative-CVR voxels. Quantitative CVR results were compared across protocols, which show that the optimized protocols yielded smaller CVR values (Opt1: 0.16 ± 0.01 %BOLD/mmHg CO2 ; Opt2: 0.15 ± 0.01 %BOLD/mmHg CO2 ) than (P < 0.001) the standard protocol (0.21 ± 0.01 %BOLD/mmHg CO2 ), but the CNR was comparable (P = 0.1) to the standard protocol. The coefficient-of-variation between repetitions was found to be 5.6 ± 1.4%, 6.3 ± 1.6%, and 6.9 ± 0.9% for the three protocols, but there were no significant differences (P = 0.65). CONCLUSION Based on the theoretical and experimental results obtained from this study, we suggest that the use of a TE shorter than those used in fMRI is necessary to minimize negative artifact in CVR results.
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Affiliation(s)
- Harshan Ravi
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
- Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, Texas, USA
- Department of Bioengineering, University of Texas at Arlington, Arlington, Texas, USA
| | - Binu P Thomas
- Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, Texas, USA
- Department of Bioengineering, University of Texas at Arlington, Arlington, Texas, USA
| | - Shin-Lei Peng
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
- Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Hanli Liu
- Department of Bioengineering, University of Texas at Arlington, Arlington, Texas, USA
| | - Hanzhang Lu
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
- Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, Texas, USA
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Karadeli HH, Giurgiutiu DV, Cloonan L, Fitzpatrick K, Kanakis A, Ozcan ME, Schwamm LH, Rost NS. FLAIR Vascular Hyperintensity is a Surrogate of Collateral Flow and Leukoaraiosis in Patients With Acute Stroke Due to Proximal Artery Occlusion. J Neuroimaging 2015; 26:219-23. [PMID: 26250448 DOI: 10.1111/jon.12274] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 05/22/2015] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Fluid attenuated inversion recovery (FLAIR) vascular hyperintensity (FVH) is a novel radiographic marker detected in acute ischemic stroke (AIS) patients, which is linked to slow blood flow and potentially salvageable brain tissue. Poor leptomeningeal collateral status in AIS patients with proximal artery occlusion (PAO) is associated with larger final infarct and worse clinical outcomes, which are also affected by severity of white matter hyperintensity (WMH). We sought to evaluate FVH utility as a marker of acute collateral vessel status and its association with WMH burden in AIS patients. METHODS Consecutive AIS patients with PAO on baseline CT angiography (CTA) were retrospectively selected from a prospectively derived database. FVH was graded by its location, degree, and score on admission MRI obtained immediately after intravenous tissue plasminogen activator administration. Leptomeningeal collateral flow grade was ranked on admission CTA. WMH volume (WMHV) was assessed using a validated volumetric protocol. Relationship between FVH, collateral flow grade, and WMHV were analyzed. RESULTS Among 39 patients (mean age 70.5 ± 12.7 years; 56% women, mean National Institutes of Health Stroke Scale score 17.2 (± 4.4)), median WMHV was 6.0 cm(3). FVH score and collateral flow grade were significantly correlated (Spearman's ρ = .41, P = .009). In a univariate regression model, FVH degree was inversely associated with WMHV (β = -.33, P = .04). CONCLUSIONS FVH score detected on acute MRI can be used as a surrogate of collateral flow grade in AIS patients. FVH degree is inversely associated with WMHV, possibly signifying diffuse disease of cerebral vasculature in patients with severe leukoaraiosis.
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Affiliation(s)
- Hasan H Karadeli
- Department of Neurology, J. Philip Kistler Stroke Research Center, Massachusetts General Hospital, 175 Cambridge Street, Suite 300, Boston, MA.,Department of Neurology, BezmialemVakıf University, Istanbul, Turkey
| | - Dan-Victor Giurgiutiu
- Department of Neurology, J. Philip Kistler Stroke Research Center, Massachusetts General Hospital, 175 Cambridge Street, Suite 300, Boston, MA.,University of Pittsburg Medical Center, Pittsburgh, PA
| | - Lisa Cloonan
- Department of Neurology, J. Philip Kistler Stroke Research Center, Massachusetts General Hospital, 175 Cambridge Street, Suite 300, Boston, MA
| | - Kaitlin Fitzpatrick
- Department of Neurology, J. Philip Kistler Stroke Research Center, Massachusetts General Hospital, 175 Cambridge Street, Suite 300, Boston, MA
| | - Allison Kanakis
- Department of Neurology, J. Philip Kistler Stroke Research Center, Massachusetts General Hospital, 175 Cambridge Street, Suite 300, Boston, MA.,University of Pittsburg Medical Center, Pittsburgh, PA
| | - Muhammed E Ozcan
- Department of Neurology, BezmialemVakıf University, Istanbul, Turkey
| | - Lee H Schwamm
- Department of Neurology, J. Philip Kistler Stroke Research Center, Massachusetts General Hospital, 175 Cambridge Street, Suite 300, Boston, MA
| | - Natalia S Rost
- Department of Neurology, J. Philip Kistler Stroke Research Center, Massachusetts General Hospital, 175 Cambridge Street, Suite 300, Boston, MA
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Examining the regional and cerebral depth-dependent BOLD cerebrovascular reactivity response at 7 T. Neuroimage 2015; 114:239-48. [DOI: 10.1016/j.neuroimage.2015.04.014] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 03/06/2015] [Accepted: 04/07/2015] [Indexed: 01/04/2023] Open
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Accelerated progression of white matter hyperintensities and subsequent risk of mortality: a 12-year follow-up study. Neurobiol Aging 2015; 36:2130-5. [DOI: 10.1016/j.neurobiolaging.2015.03.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 02/20/2015] [Accepted: 03/03/2015] [Indexed: 11/20/2022]
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49
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Hemodynamic Control and Delirium. CURRENT ANESTHESIOLOGY REPORTS 2015. [DOI: 10.1007/s40140-014-0096-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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50
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Sam K, Poublanc J, Sobczyk O, Han JS, Battisti-Charbonney A, Mandell DM, Tymianski M, Crawley AP, Fisher JA, Mikulis DJ. Assessing the effect of unilateral cerebral revascularisation on the vascular reactivity of the non-intervened hemisphere: a retrospective observational study. BMJ Open 2015; 5:e006014. [PMID: 25673438 PMCID: PMC4325130 DOI: 10.1136/bmjopen-2014-006014] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVES Unilateral haemodynamically significant large-vessel intracranial stenosis may be associated with reduced blood-oxygen-level-dependent (BOLD) cerebrovascular reactivity (CVR), an indicator of autoregulatory reserve. Reduced CVR has been associated with ipsilateral cortical thinning and loss in cognitive function. These effects have been shown to be reversible following revascularisation. Our aim was to study the effects of unilateral revascularisation on CVR in the non-intervened hemisphere in bilateral steno-occlusive or Moyamoya disease. STUDY DESIGN A retrospective observational study. SETTING A routine follow-up assessment of CVR after a revascularisation procedure at a research teaching hospital in Toronto (Journal wants us to generalise). PARTICIPANTS Thirteen patients with bilateral Moyamoya disease (age range 18 to 52 years; 3 males), seven patients with steno-occlusive disease (age range 18 to 78 years; six males) and 27 approximately age-matched normal control subjects (age range 19-71 years; 16 males) with no history or findings suggestive of any neurological or systemic disease. INTERVENTION Participants underwent BOLD CVR MRI using computerised prospective targeting of CO2, before and after unilateral revascularisation (extracranial-intracranial bypass, carotid endarterectomy or encephaloduroarteriosynangiosis). Pre-revascularisation and post-revascularisation CVR was assessed in each major arterial vascular territory of both hemispheres. RESULTS As expected, surgical revascularisation improved grey matter CVR in the middle cerebral artery (MCA) territory of the intervened hemisphere (0.010±0.023 to 0.143±0.010%BOLD/mm Hg, p<0.01). There was also a significant post-revascularisation improvement in grey matter CVR in the MCA territory of the non-intervened hemisphere (0.101±0.025 to 0.165±0.015%BOLD/mm Hg, p<0.01). CONCLUSIONS Not only does CVR improve in the hemisphere ipsilateral to a flow restoration procedure, but it also improves in the non-intervened hemisphere. This highlights the potential of CVR mapping for staging and evaluating surgical interventions.
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Affiliation(s)
- Kevin Sam
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Julien Poublanc
- Division of Neuroradiology, Joint Department of Medical Imaging of the University Health Network, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Olivia Sobczyk
- Division of Neuroradiology, Joint Department of Medical Imaging of the University Health Network, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Jay S Han
- Division of Neuroradiology, Joint Department of Medical Imaging of the University Health Network, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Anne Battisti-Charbonney
- Division of Neuroradiology, Joint Department of Medical Imaging of the University Health Network, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Daniel M Mandell
- Division of Neuroradiology, Joint Department of Medical Imaging of the University Health Network, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Michael Tymianski
- Division of Neurosurgery, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Adrian P Crawley
- Division of Neuroradiology, Joint Department of Medical Imaging of the University Health Network, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Joseph A Fisher
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Department of Anaesthesia, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - David J Mikulis
- Division of Neuroradiology, Joint Department of Medical Imaging of the University Health Network, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada
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