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Quantifying cerebral blood arrival times using hypoxia-mediated arterial BOLD contrast [article]

Alex A. Bhogal, Ece Su Sayin, Julien Poublanc, Jim Duffin, Joseph A. Fisher, Olivia Sobcyzk, David J. Mikulis
2022 bioRxiv   pre-print
A combination of hemodynamic lag with a modified carpet plot analysis yielded lag, onset (blood arrival), mean transit time (MTT) and hypoxic response information, which is indicative of relative total  ...  In cases with exhausted reserve capacity or confounding flow effects such as vascular steal, dOHb-BOLD can potentially inform on collateral flow pathways to provide a valuable compliment to clinical vascular  ...  Dutch research council talent grant awarded to Alex A.  ... 
doi:10.1101/2022.03.27.485933 fatcat:ykdst5advfbqhmjblzqddurb2m

The many layers of BOLD. On the contribution of different vascular compartments to laminar fMRI [article]

Wouter Schellekens, Alex A Bhogal, Emiel C.A. Roefs, Mario G Baez-Yanez, Jeroen C.W. Siero, Natalia Petridou
2021 bioRxiv   pre-print
Most fMRI studies make use of the Blood-Oxygen-Level Dependent (BOLD) signal, arising from a complex interaction of changes in cerebral blood flow (CBF) and volume (CBV), and venous oxygenation.  ...  Finally, there is roughly a 35% difference in CBV estimates between the macro- and micro-vascular compartments, although this relative difference is approximately uniform across cortical depth.  ...  by a +10 mmHG PetCO 2 increase.  ... 
doi:10.1101/2021.10.21.465359 fatcat:lbdlw2wiufavvdnfqs3sifgwfy

Medullary vein architecture modulates the white matter BOLD cerebrovascular reactivity signal response to CO2: observations from high-resolution T2* weighted imaging at 7T [article]

Alex A Bhogal
2021 bioRxiv   pre-print
In this work, high-resolution T2*-weighted anatomical images combined with BOLD imaging during a hypercapnic breathing protocol were acquired using a 7 tesla MRI system.  ...  Finally, the lag-corrected CVR showed a very strong correlation with the base CVR with a Pearson value of 0.94.  ...  Data Acquisition MRI acquisition was done using a Philips 7 tesla MRI scanner (Philips, Best, The Netherlands) using a 32 channel receive coil in combination with a volume transmit coil (Nova Medical,  ... 
doi:10.1101/2021.09.03.458842 fatcat:ed6qp52onjbini33y433ewoymm

Insights Into Cerebral Tissue-Specific Response to Respiratory Challenges at 7T: Evidence for Combined Blood Flow and CO2-Mediated Effects

Allen A. Champagne, Alex A. Bhogal
2021 Frontiers in Physiology  
In a subset of seven participants, a combined HC+HO block, referred as the "BOOST" protocol, was also acquired.  ...  Cerebrovascular reactivity (CVR) mapping is finding increasing clinical applications as a non-invasive probe for vascular health.  ...  ; Battisti-Charbonney et al., 2011; Bhogal et al., 2014b) .  ... 
doi:10.3389/fphys.2021.601369 pmid:33584344 pmcid:PMC7876301 fatcat:a3t7wnmwgbbyjjbfc62dag7rrm

Vascular reactivity in small cerebral perforating arteries with 7 T phase contrast MRI – A proof of concept study

Lennart J. Geurts, Alex A. Bhogal, Jeroen C.W. Siero, Peter R. Luijten, Geert Jan Biessels, Jaco J.M. Zwanenburg
2018 NeuroImage  
A B S T R A C T Existing cerebrovascular reactivity (CVR) techniques assess flow reactivity in either the largest cerebral vessels or at the level of the parenchyma.  ...  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  ...  Bhogal et al. assessed reactivity with BOLD, and reported a lower CVR of 0.21%/mmHg and 0.40%/mmHg in white and grey matter, respectively (Bhogal et al., 2015) .  ... 
doi:10.1016/j.neuroimage.2018.01.055 pmid:29408324 pmcid:PMC5915583 fatcat:z5ykhjzldvbqxi2mldj5362sbm

Glutamate levels across deep brain structures in patients with a psychotic disorder and its relation with cognitive functioning [article]

Tommy A.A. Broeders, Alex A Bhogal, Lisan M Morsinkhof, Menno Schoonheim, Christian H Röder, Mirte E.J. Edens, Dennis W.J. Klomp, Jannie P. Wijnen, Christiaan H. Vinkers
2021 medRxiv   pre-print
A 7 tesla MRI scanner combined with a unique lipid suppression coil and subject specific water signal suppression pulses were used to acquire high-resolution magnetic resonance spectroscopic imaging data  ...  Glutamate seems to play a prominent role, but knowledge on its role in deep gray matter regions is limited and previous studies have yielded heterogeneous results.  ...  CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.  ... 
doi:10.1101/2021.02.01.21250977 fatcat:o36wrwoq7bccbnqklxgbv6v3em

Quantitative T1 mapping under precisely controlled graded hyperoxia at 7T

Alex A Bhogal, Jeroen CW Siero, Jaco Zwanenburg, Peter R Luijten, Marielle EP Philippens, Hans Hoogduin
2016 Journal of Cerebral Blood Flow and Metabolism  
The T1 of peripheral cerebrospinal fluid located within the sulci, however, was reduced as a function of PetO 2 .  ...  (a) Left is a single slice from a T1 map obtained at baseline PetO 2 .  ...  (a) Left is a single slice from a T1 map obtained at baseline PetO 2 .  ... 
doi:10.1177/0271678x16656864 pmid:27354092 pmcid:PMC5453465 fatcat:k4nzyyrsv5efplwxdgkbxmk6ym

Establishing upper limits on neuronal activity-evoked pH changes with APT-CEST MRI at 7 T

Vitaliy Khlebnikov, Jeroen C.W. Siero, Alex A. Bhogal, Peter R. Luijten, Dennis W.J. Klomp, Hans Hoogduin
2017 Magnetic Resonance in Medicine  
Results: In theory, a three-component general linear model was capable of separating the effects of blood oxygenation level-dependent contrast and pH.  ...  The Bloch-McConnell equations indicated that a change in pH of 0.03 should be measurable at the experimentally determined temporal signal-to-noise ratio of 108.  ...  and a finite echo time (Fig. 3b) .  ... 
doi:10.1002/mrm.27013 pmid:29154463 pmcid:PMC5900917 fatcat:tkattw4zebfwxdrptdrehpqc7q

Lipid suppressed and tissue-fraction corrected metabolic distributions in human central brain structures using 2D 1H Magnetic Resonance Spectroscopic Imaging at 7 tesla [article]

Alex A Bhogal, Tommy A Broeders, Lisan Morsinkhof, Mirte Edens, Sahar Nassirpour, Paul Chang, Dennis W.J. Klomp, Christiaan Vinkers, Jannie P Wijnen
2020 bioRxiv   pre-print
Magnetic resonance spectroscopic imaging (MRSI) has the potential to add a layer of understanding of the neurobiological mechanisms underlying brain diseases, disease progression, and treatment efficacy  ...  these factors and to develop an acquisition, reconstruction and post-processing pipeline to derive lipid suppressed metabolite values based on Free Induction Decay (FID-MRSI) measurements made using a  ...  Acknowledgements This research was supported by a Brain and Behavior Research Foundation NARSAD Young Investigator Award (Christiaan Vinkers, 24074).  ... 
doi:10.1101/2020.06.09.142646 fatcat:7qinicvwrjglnagqrbqf3ufuvy

Contralateral improvement of cerebrovascular reactivity and TIA frequency after unilateral revascularization surgery in moyamoya vasculopathy

Pieter T. Deckers, Wytse van Hoek, Annick Kronenburg, Maqsood Yaqub, Jeroen C.W. Siero, Alex A. Bhogal, Bart N.M.v. Berckel, Albert van der Zwan, Kees P.J. Braun
2021 NeuroImage: Clinical  
Conservatively treated patients were showed as a comparison group.  ...  Moyamoya vasculopathy is a rare, often bilateral disease characterized by progressive stenosis and occlusion of the distal internal carotid artery, leading to a progressive deterioration of cerebrovascular  ...  Alex A. Bhogal: Conceptualization, Visualization, Supervision, Writing -review & editing. Bart N.M. van Berckel: Resources, Writing -review & editing.  ... 
doi:10.1016/j.nicl.2021.102684 fatcat:ju6b4q5yzvbgxan7jy4siw65l4

Effect sizes of BOLD CVR, resting-state signal fluctuations and time delay measures for the assessment of hemodynamic impairment in carotid occlusion patients

Jill B. De Vis, Alex A. Bhogal, Jeroen Hendrikse, Esben T. Petersen, Jeroen C.W. Siero
2018 NeuroImage  
A R T I C L E I N F O Keywords: Magnetic resonance imaging MRI Blood oxygen level dependent BOLD Brain fMRI Resting-state fMRI Cerebrovascular reactivity Cerebrovascular disease A B S T R A C T Background  ...  and purpose: The BOLD signal amplitude as a response to a hypercapnia stimulus is commonly used to assess cerebrovascular reserve.  ...  ., 2015) , and BOLD signal change as a response to a progressively increasing hypercapnic stimulus (Bhogal et al., 2016) were evaluated.  ... 
doi:10.1016/j.neuroimage.2018.06.017 pmid:29913284 pmcid:PMC6057274 fatcat:o25jaozqc5h6tp6pv7zjxb7fxe

Hemodynamic and metabolic changes during hypercapnia with normoxia and hyperoxia using pCASL and TRUST MRI in healthy adults

Pieter T Deckers, Alex A Bhogal, Mathijs BJ Dijsselhof, Carlos C Faraco, Peiying Liu, Hanzhang Lu, Manus J Donahue, Jeroen C.W Siero
2021 Journal of Cerebral Blood Flow and Metabolism  
Our findings indicate that 'CO2 in air' is not iso-metabolic, while carbogen appears to elicit a mixed effect; the CMRO2 reduction during hypercapnia is mitigated when including hyperoxia.  ...  OEF ¼ O 2 ½ a -O 2 ½ v O 2 ½ a (2) CMRO 2 ¼ CBF Á ð O 2 ½ a -O 2 ½ v Þ (3) with O 2 ½ a ¼ Y a Á C h þ p a O 2 Á C d (4) and O 2 ½ v ¼ Y v Á C h þ p v O 2 Á C d (5) Constants C h (912 lmol O 2 /100 ml blood  ...  Ya pEtCO 2 pCASL CBF [O 2 ] a = Ya • Ch + paO 2 • Cd [O 2 ] v = Yv • Ch + pvO 2 • Cd OEF = ([O 2 ] a -[O 2 ] v )/[O] a CMRO 2 = CBF • ([O 2 ] a -[O 2 ] v ) CMRO2 and OEF estimation.  ... 
doi:10.1177/0271678x211064572 pmid:34851757 pmcid:PMC9014679 fatcat:6mgrx3ovxva57nilzdejrooyym

sj-pdf-1-jcb-10.1177_0271678X211064572 - Supplemental material for Hemodynamic and metabolic changes during hypercapnia with normoxia and hyperoxia using pCASL and TRUST MRI in healthy adults

Pieter T Deckers, Alex A Bhogal, Mathijs BJ Dijsselhof, Carlos C Faraco, Peiying Liu, Hanzhang Lu, Manus J Donahue, Jeroen C.W Siero
2021 Figshare  
A Bhogal, Mathijs BJ Dijsselhof, Carlos C Faraco, Peiying Liu, Hanzhang Lu, Manus J Donahue and Jeroen C.W Siero in Journal of Cerebral Blood Flow & Metabolism  ...  material, sj-pdf-1-jcb-10.1177_0271678X211064572 for Hemodynamic and metabolic changes during hypercapnia with normoxia and hyperoxia using pCASL and TRUST MRI in healthy adults by Pieter T Deckers, Alex  ...  The conversion of pCASL measured ∆M to CBF can be considered as a scaling problem, when applying a single-compartment kinetic model (Buxton et al. 1 ).  ... 
doi:10.25384/sage.17113198.v1 fatcat:aaz7yuwnyvd7he3jgpvgdeipsu

GLS hyperactivity causes glutamate excess, infantile cataract and profound developmental delay

Lynne Rumping, Federico Tessadori, Petra JW Pouwels, Esmee Vringer, Jannie P Wijnen, Alex A Bhogal, Sanne MC Savelberg, Karen J Duran, Mark JG Bakkers, Rúben JJ Ramos, Peter AW Schellekens, Hester Y Kroes (+14 others)
2018 Human Molecular Genetics  
These examples indicate that a heterozygous variant is sufficient to induce overall enzyme hyperactivity.In this study, we characterize a de novo hypermorphic heterozygous GLS variant found in a patient  ...  The consensus were determined in JalView(33) and 298 fraction of the modal residue in a column were used for generating a color gradients which was 299 mapped onto the GLS structure as a measure of conservation  ...  Images were obtained with a fluorescence microscope.  ... 
doi:10.1093/hmg/ddy330 pmid:30239721 fatcat:65im322rvvadxj7lpp6rl4y4pa

Lipid-suppressed and tissue-fraction corrected metabolic distributions in human central brain structures using 2D 1 H magnetic resonance spectroscopic imaging at 7 T

Alex A Bhogal, Tommy A A Broeders, Lisan Morsinkhof, Mirte Edens, Sahar Nassirpour, Paul Chang, Dennis W J Klomp, Christiaan H Vinkers, Jannie P Wijnen
2020
Magnetic resonance spectroscopic imaging (MRSI) has the potential to add a layer of understanding of the neurobiological mechanisms underlying brain diseases, disease progression, and treatment efficacy  ...  and to develop an acquisition, reconstruction, and postprocessing pipeline to derive lipid-suppressed metabolite values of central brain structures based on free-induction decay measurements made using a  ...  O RCI D Alex A.  ... 
doi:10.1002/brb3.1852 pmid:33216472 fatcat:pv7uqwqhnfbmfiib5hdvskm45q
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