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Cao W, Chang YV, Englund EK, Song HK, Barhoum S, Rodgers ZB, Langham MC, Wehrli FW. High-speed whole-brain oximetry by golden-angle radial MRI. Magn Reson Med 2017; 79:217-223. [PMID: 28342212 DOI: 10.1002/mrm.26666] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2016] [Revised: 01/18/2017] [Accepted: 02/11/2017] [Indexed: 11/08/2022]
Abstract
PURPOSE To determine whole-brain cerebral metabolic rate of oxygen (CMRO2 ), an improved imaging approach, based on radial encoding, termed radial OxFlow (rOxFlow), was developed to simultaneously quantify draining vein venous oxygen saturation (SvO2 ) and total cerebral blood flow (tCBF). METHODS To evaluate the efficiency and precision of the rOxFlow sequence, 10 subjects were studied during a paradigm of repeated breath-holds with both rOxFlow and Cartesian OxFlow (cOxFlow) sequences. CMRO2 was calculated at baseline from OxFlow-measured data assuming an arterial O2 saturation of 97%, and the SvO2 and tCBF breath-hold responses were quantified. RESULTS Average neurometabolic-vascular parameters across the 10 subjects for cOxFlow and rOxFlow were, respectively: SvO2 (%) baseline: 64.6 ± 8.0 versus 64.2 ± 6.6; SvO2 peak: 70.5 ± 8.5 versus 72.6 ± 5.4; tCBF (mL/min/100 g) baseline: 39.2 ± 3.8 versus 40.6 ± 8.0; tCBF peak: 53.2 ± 5.1 versus 56.1 ± 11.7; CMRO2 (µmol O2 /min/100 g) baseline: 111.5 ± 26.8 versus 120.1 ± 19.6. The above measures were not significantly different between sequences (P > 0.05). CONCLUSION There was good agreement between the two methods in terms of the physiological responses measured. Comparing the two, rOxFlow provided higher temporal resolution and greater flexibility for reconstruction while maintaining high SNR. Magn Reson Med 79:217-223, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Wen Cao
- Laboratory for Structural, Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yulin V Chang
- Laboratory for Structural, Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Erin K Englund
- Laboratory for Structural, Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Hee Kwon Song
- Laboratory for Structural, Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Suliman Barhoum
- Laboratory for Structural, Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Zachary B Rodgers
- Laboratory for Structural, Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Michael C Langham
- Laboratory for Structural, Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Felix W Wehrli
- Laboratory for Structural, Physiologic and Functional Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Barhoum S, Palit S, Yethiraj A. Diffusion NMR studies of macromolecular complex formation, crowding and confinement in soft materials. Prog Nucl Magn Reson Spectrosc 2016; 94-95:1-10. [PMID: 27247282 DOI: 10.1016/j.pnmrs.2016.01.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 01/25/2016] [Accepted: 01/28/2016] [Indexed: 06/05/2023]
Abstract
Label-free methods to obtain hydrodynamic size from diffusion measurements are desirable in environments that contain multiple macromolecular species at a high total concentration: one example is the crowded cellular environment. In complex, multi-species macromolecular environments - in this article, we feature aqueous systems involving polymers, surfactants and proteins - the link between dynamics and size is harder to unpack due to macromolecular crowding and confinement. In this review, we demonstrate that the pulsed-field gradient NMR technique, with its spectral separation of different chemical components, is ideal for studying the dynamics of the entire system simultaneously and without labelling, in a wide range of systems. The simultaneous measurement of the dynamics of multiple components allows for internal consistency checks and enables quantitative statements about the link between macromolecular dynamics, size, complex formation and crowding in soft materials.
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Affiliation(s)
- Suliman Barhoum
- Department of Physics and Physical Oceanography, Memorial University, St. John's, Newfoundland and Labrador, Canada
| | - Swomitra Palit
- Department of Physics and Physical Oceanography, Memorial University, St. John's, Newfoundland and Labrador, Canada
| | - Anand Yethiraj
- Department of Physics and Physical Oceanography, Memorial University, St. John's, Newfoundland and Labrador, Canada
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Langham MC, Zhou Y, Chirico EN, Magland JF, Sehgal CM, Englund EK, Mohler ER, Guo W, Barhoum S, Wehrli FW. Effects of age and smoking on endothelial function assessed by quantitative cardiovascular magnetic resonance in the peripheral and central vasculature. J Cardiovasc Magn Reson 2015; 17:19. [PMID: 25884943 PMCID: PMC4332734 DOI: 10.1186/s12968-015-0110-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 01/06/2015] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Both age and smoking promote endothelial dysfunction and impair vascular reactivity. Here, we tested this hypothesis by quantifying new cardiovascular magnetic resonance (CMR)-based biomarkers in smokers and nonsmokers. METHODS Study population: young non-smokers (YNS: N = 45, mean age = 30.2 ± 0.7 years), young smokers (YS: N = 39 mean age 32.1 ± 0.7 years), older non-smokers (ONS: N = 45, mean age = 57.8 ± 0.6 years), and older smokers (OS: N = 40, mean age = 56.3 ± 0.6 years), all without overt cardiovascular disease. Vascular reactivity was evaluated following cuff-induced hyperemia via time-resolved blood flow velocity and oxygenation (SvO2) in the femoral artery and vein, respectively. SvO2 dynamics yielded washout time (time to minimum SvO2), resaturation rate (upslope) and maximum change from baseline (overshoot). Arterial parameters included pulse ratio (PR), hyperemic index (HI) and duration of hyperemia (TFF). Pulse-wave velocity (PWV) was assessed in aortic arch, thoracoabdominal aorta and iliofemoral arteries. Ultrasound-based carotid intimal-medial thickness (IMT) and brachial flow-mediated dilation were measured for comparison. RESULTS Age and smoking status were independent for all parameters. Smokers had reduced upslope (-28.4%, P < 0.001), increased washout time (+15.3%, P < 0.01), and reduced HI (-19.5%, P < 0.01). Among non-smokers, older subjects had lower upslope (-22.7%, P < 0.01) and overshoot (-29.4%, P < 0.01), elevated baseline pulse ratio (+14.9%, P < 0.01), central and peripheral PWV (all P < 0.05). Relative to YNS, YS had lower upslope (-23.6%, P < 0.01) and longer washout time (13.5%, P < 0.05). Relative to ONS, OS had lower upslope (-33.0%, P < 0.01). IMT was greater in ONS than in YNS (+45.6%, P < 0.001), and also in YS compared to YNS (+14.7%, P < 0.05). CONCLUSIONS Results suggest CMR biomarkers of endothelial function to be sensitive to age and smoking independent of each other.
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Affiliation(s)
- Michael C Langham
- Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA, 19104, USA.
| | - Yongxia Zhou
- Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA, 19104, USA.
| | - Erica N Chirico
- Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA, 19104, USA.
| | - Jeremy F Magland
- Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA, 19104, USA.
| | - Chandra M Sehgal
- Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA, 19104, USA.
| | - Erin K Englund
- Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA, 19104, USA.
| | - Emile R Mohler
- Department of Medicine, University of Pennsylvania Medical Center, Philadelphia, PA, USA.
| | - Wensheng Guo
- Department of Biostatistics and Epidemiology, University of Pennsylvania Medical Center, Philadelphia, PA, USA.
| | - Suliman Barhoum
- Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA, 19104, USA.
| | - Felix W Wehrli
- Department of Radiology, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA, 19104, USA.
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Barhoum S, Rodgers ZB, Langham M, Magland JF, Li C, Wehrli FW. Comparison of MRI methods for measuring whole-brain venous oxygen saturation. Magn Reson Med 2014; 73:2122-8. [PMID: 24975122 DOI: 10.1002/mrm.25336] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 06/02/2014] [Accepted: 06/04/2014] [Indexed: 01/18/2023]
Abstract
PURPOSE In this work, we compare susceptometry-based oximetry (SBO) and two T2 -based methods for estimating resting baseline SvO2 in the superior sagittal sinus (SSS). METHODS SBO is a field-mapping technique whereas in T2 -based methods the intravascular blood signal is isolated either with velocity-encoded projections [projection-based T2 (PT2 )] or a tag-control scheme [T2 -relaxation under spin tagging (TRUST)] after T2 -preparation. The measurements were performed on twelve healthy subjects (mean age = 33 ± 6 years) at 3 Tesla field strength. The reliability, precision, and reproducibility were examined for the three techniques. RESULTS The mean (± standard deviation) SvO2 quantified by SBO, PT2 , and TRUST were found to be 65.9 ± 3.3, 65.6 ± 3.5, and 63.2 ± 4.1%. The standard deviation (SD) for 10 consecutive measurements in the quantified SvO2 was less than 2.7%, 4.7%, and 5.0% for SBO, PT2 , and TRUST across all subjects. In testing reproducibility across different days, the resulting SDs were 2.6, 3.5, and 2.0% for SBO, PT2 , and TRUST. CONCLUSION The results indicate that all three SvO2 quantification techniques to be reliable with good agreement between PT2 and SBO while TRUST yielded slightly lower values compared with the other two techniques.
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Affiliation(s)
- Suliman Barhoum
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Zachary B Rodgers
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Michael Langham
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jeremy F Magland
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Cheng Li
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Felix W Wehrli
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Barhoum S, Booth V, Yethiraj A. Diffusion NMR study of complex formation in membrane-associated peptides. Eur Biophys J 2013; 42:405-14. [DOI: 10.1007/s00249-013-0890-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 01/17/2013] [Indexed: 01/12/2023]
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Barhoum S, Yethiraj A. NMR Detection of an Equilibrium Phase Consisting of Monomers and Clusters in Concentrated Lysozyme Solutions. J Phys Chem B 2010; 114:17062-7. [DOI: 10.1021/jp108995k] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Suliman Barhoum
- Department of Physics and Physical Oceanography, Memorial University, St. John’s, Newfoundland and Labrador, Canada
| | - Anand Yethiraj
- Department of Physics and Physical Oceanography, Memorial University, St. John’s, Newfoundland and Labrador, Canada
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