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Malferrari G, Merli N, Inchingolo V, Siniscalchi A, Laterza D, Monaco D, Arnone G, Zini A, Prada F, Azzini C, Pugliatti M. Role of Advanced Hemodynamic Ultrasound Evaluation in the Differential Diagnosis of Middle Cerebral Artery Stenosis: Introducing Morphological Criteria. Ultrasound Med Biol 2023; 49:2428-2435. [PMID: 37550172 DOI: 10.1016/j.ultrasmedbio.2023.07.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 11/24/2022] [Revised: 06/28/2023] [Accepted: 07/09/2023] [Indexed: 08/09/2023]
Abstract
OBJECTIVE The aim of the work described here was to determine the possible impact of the new technique advanced hemodynamic ultrasound evaluation (AHUSE) in identification of severe intracranial stenosis. Transcranial Doppler (TCD) and transcranial color-coded Doppler (TCCD) provide reliable velocimetric data, the indirect analysis of which allows us to obtain information on the patency of vessels and assumed stenosis range. However, very tight stenoses (>95%) cannot be detected with velocimetric criteria because of spectrum drops and the absence of high velocities, so that the right curve of the Spencer equation cannot be solved. Likewise, high velocities are not detected when analyzing morphologically long stenosis. Furthermore, the current classifications based on velocimetric criteria do not provide any categorization on stenoses with multiple acceleration points (MAPs). METHODS With this Technical Note we aim to introduce, in addition to velocimetric criteria, more morphological criteria based on TCCD with the algorithm of AHUSE to optimize the characterization of intracranial stenosis (IS). TCCD-AHUSE relies on intensity-based next-generation techniques and can be used to identify IS with MAPs and simultaneously perform a morphological assessment of the stenosis length. RESULTS We introduce a new technical ultrasound (U) approach that we tested in a sample of four different types of stenoses combining velocimetric data and AHUSE using Esaote Microvascularization (MicroV) technique to the M1 tract of the middle cerebral artery (MCA). CONCLUSION The authors believe that a multiparametric evaluation is more sensitive and supports the clinician by introducing the morphological concept, not just the velocimetric concept, to differentiate the IS pattern of MCA. The potential for developing a diagnostic/prognostic algorithm is discussed.
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Affiliation(s)
- Giovanni Malferrari
- Stroke Unit and Neurology Unit, Azienda Unità Sanitaria Locale-IRCCS, Reggio Emilia, Italy.
| | - Nicola Merli
- Department of Neuroscience and Rehabilitation, University of Ferrara, Italy
| | - Vincenzo Inchingolo
- Neurology Unit, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Antonio Siniscalchi
- Department of Neurology and Stroke Unit, Annunziata Hospital, Cosenza, Italy
| | - Domenico Laterza
- Neurology and Stroke Unit, Nuovo Ospedale degli Infermi, Biella (BI), Italy
| | - Daniela Monaco
- Department of Emergency Neurology and Stroke Unit, "S. Spirito" Hospital, Pescara, Italy
| | - Giorgia Arnone
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Neurologia e Rete Stroke Metropolitana, Ospedale Maggiore, Bologna, Italy
| | - Andrea Zini
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Neurologia e Rete Stroke Metropolitana, Ospedale Maggiore, Bologna, Italy
| | - Francesco Prada
- Acoustic Neuroimaging and Therapy Lab, Fondazione IRCCS Istituto Neurologico C. Besta, Milano, Italy; Department of Neurological Surgery, University of Virginia, Charlottesville, VA, USA; Focused Ultrasound Foundation, Charlottesville, VA, USA
| | - Cristiano Azzini
- Stroke Unit and Neurology Unit, S. Anna University Hospital, Ferrara Italy
| | - Maura Pugliatti
- Department of Neuroscience and Rehabilitation, University of Ferrara, Italy; S. Anna University Hospital, Ferrara Italy
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Williams KA, Shields A, Nagesh SVS, Bednarek DR, Rudin S, Ionita CN. Geometrically independent contrast dilution gradient (CDG) velocimetry using photon-counting 1000 fps High Speed Angiography (HSA) for 2D velocity distribution estimation. Proc SPIE Int Soc Opt Eng 2023; 12468:124680Q. [PMID: 37425073 PMCID: PMC10327489 DOI: 10.1117/12.2654308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Purpose Previous studies have demonstrated the efficacy of contrast dilution gradient (CDG) analysis in determining large vessel velocity distributions from 1000 fps high-speed angiography (HSA). However, the method required vessel centerline extraction, which made it applicable only to non-tortuous geometries using a highly specific contrast injection technique. This study seeks to remove the need for a priori knowledge regarding the direction of flow and modify the vessel sampling method to make the algorithm more robust to non-linear geometries. Materials and Methods 1000 fps HSA acquisitions were obtained in vitro with a benchtop flow loop using the XC-Actaeon (Varex Inc.) photon-counting detector, and in silico using a passive-scalar transport model within a computational fluid dynamics (CFD) simulation. CDG analyses were obtained using gridline sampling across the vessel, and subsequent 1D velocity measurement in both the x- and y-directions. The velocity magnitudes derived from the component CDG velocity vectors were aligned with CFD results via co-registration of the resulting velocity maps and compared using mean absolute percent error (MAPE) between pixels values in each method after temporal averaging of the 1-ms velocity distributions. Results Regions well-saturated with contrast throughout the acquisition showed agreement when compared to CFD (MAPE of 18% for the carotid bifurcation inlet and MAPE of 27% for the internal carotid aneurysm), with respective completion times of 137 seconds and 5.8 seconds. Conclusions CDG may be used to obtain velocity distributions in and surrounding vascular pathologies provided the contrast injection is sufficient to provide a gradient, and diffusion of contrast through the system is negligible.
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Affiliation(s)
- Kyle A Williams
- Department of Biomedical Engineering, University at Buffalo, Buffalo, NY 14228
- Canon Stroke and Vascular Research Center, Buffalo, NY 14208
- Department of Medical Physics, University at Buffalo, Buffalo, NY 14228
| | - Allison Shields
- Canon Stroke and Vascular Research Center, Buffalo, NY 14208
- Department of Medical Physics, University at Buffalo, Buffalo, NY 14228
- University at Buffalo Neurosurgery, University at Buffalo Jacobs School of Medicine, Buffalo, NY 14228
| | - S V Setlur Nagesh
- Canon Stroke and Vascular Research Center, Buffalo, NY 14208
- University at Buffalo Neurosurgery, University at Buffalo Jacobs School of Medicine, Buffalo, NY 14228
| | - Daniel R Bednarek
- Department of Biomedical Engineering, University at Buffalo, Buffalo, NY 14228
- Canon Stroke and Vascular Research Center, Buffalo, NY 14208
- Department of Medical Physics, University at Buffalo, Buffalo, NY 14228
- University at Buffalo Neurosurgery, University at Buffalo Jacobs School of Medicine, Buffalo, NY 14228
| | - Stephen Rudin
- Department of Biomedical Engineering, University at Buffalo, Buffalo, NY 14228
- Canon Stroke and Vascular Research Center, Buffalo, NY 14208
- Department of Medical Physics, University at Buffalo, Buffalo, NY 14228
- University at Buffalo Neurosurgery, University at Buffalo Jacobs School of Medicine, Buffalo, NY 14228
| | - Ciprian N Ionita
- Department of Biomedical Engineering, University at Buffalo, Buffalo, NY 14228
- Canon Stroke and Vascular Research Center, Buffalo, NY 14208
- Department of Medical Physics, University at Buffalo, Buffalo, NY 14228
- University at Buffalo Neurosurgery, University at Buffalo Jacobs School of Medicine, Buffalo, NY 14228
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Bartol IK, Ganley AM, Tumminelli AN, Krueger PS, Thompson JT. Vectored jets power arms-first and tail-first turns differently in brief squid with assistance from fins and keeled arms. J Exp Biol 2022; 225:275902. [PMID: 35786780 DOI: 10.1242/jeb.244151] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [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: 02/18/2022] [Accepted: 06/29/2022] [Indexed: 11/20/2022]
Abstract
Squids maneuver to capture prey, elude predators, navigate complex habitats, and deny rivals access to mates. Despite the ecological importance of this essential locomotive function, limited quantitative data on turning performance and wake dynamics of squids are available. To better understand the contribution of the jet, fins, and arms to turns, the role of orientation (i.e., arms-first vs tail-first) in maneuvering, and relationship between jet flow and turning performance, kinematic and 3D velocimetry data were collected in tandem from brief squid Lolliguncula brevis. The pulsed jet, which can be vectored to direct flows, was the primary driver of most turning behaviors, producing flows with the highest impulse magnitude and angular impulse about the main axis of the turn (yaw) and secondary axes (roll and pitch). The fins and keeled arms played subordinate but important roles in turning performance, contributing to angular impulse, stabilizing the maneuver along multiple axes, and/or reducing rotational resistance. Orientation affected turning performance and dynamics, with tail-first turns being associated with greater impulse and angular impulse, longer jet structures, higher jet velocities, and greater angular turning velocities than arms-first turns. Conversely, arms-first turns involved shorter, slower jets with less impulse, but these directed short pulses resulted in lower minimum length-specific turning radii. Although the length-to-diameter ratio (L/D) of ejected jet flow was a useful metric for characterizing vortical flow features, it, by itself, was not a reliable predictor of angular velocity or turning radii, which reflects the complexity of the squid multi-propulsor system.
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Affiliation(s)
- Ian K Bartol
- Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529, USA
| | - Alissa M Ganley
- Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529, USA
| | - Amanda N Tumminelli
- Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529, USA
| | - Paul S Krueger
- Department of Mechanical Engineering, Southern Methodist University, Dallas, TX 75275, USA
| | - Joseph T Thompson
- Department of Biology, Franklin and Marshall College, Lancaster, PA 17604, USA
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Williams KA, Shields A, Nagesh SVS, Bednarek DR, Rudin S, Ionita CN. 2D vessel contrast dilution gradient (CDG) analysis using 1000 fps high speed angiography (HSA) for velocity distribution estimation. Proc SPIE Int Soc Opt Eng 2022; 12031:1203107. [PMID: 35982769 PMCID: PMC9385177 DOI: 10.1117/12.2611790] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
PURPOSE Contrast dilution gradient (CDG) analysis is a technique used to extract velocimetric 2D information from digitally subtracted angiographic (DSA) acquisitions. This information may then be used by clinicians to quantitatively assess the effects of endovascular treatment on flow conditions surrounding pathologies of interest. The method assumes negligible diffusion conditions, making 1000 fps high speed angiography (HSA), in which diffusion between 1 ms frames may be neglected, a strong candidate for velocimetric analysis using CDG. Previous studies have demonstrated the success of CDG analysis in obtaining velocimetric one-dimensional data at the arterial centerline of simple vasculature. This study seeks to resolve velocity distributions across the entire vessel using 2D-CDG analysis with HSA acquisitions. MATERIALS AND METHODS HSA acquisitions for this study were obtained in vitro with a benchtop flow loop at 1000 fps using the XC-Actaeon (Direct Conversion Inc.) photon counting detector. 2D-CDG analyses were compared with computational fluid dynamics (CFD) via automatic co-registration of the results from each velocimetry method. This comparison was performed using mean absolute error between pixel values in each method (after temporal averaging). RESULTS CDG velocity magnitudes were slightly under approximated relative to CFD results (mean velocity: 27 cm/s, mean absolute error: 4.3 cm/s) as a result of incomplete contrast filling. Relative 2D spatial velocity distributions in CDG analysis agreed well with CFD distributions qualitatively. CONCLUSIONS CDG may be used to obtain velocity distributions in and surrounding vascular pathologies provided diffusion is negligible relative to convection in the flow, given a continuous gradient of contrast.
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Affiliation(s)
- Kyle A Williams
- Department of Biomedical Engineering, University at Buffalo, Buffalo, NY 14228
- Canon Stroke and Vascular Research Center, Buffalo, NY 14208
| | - Allison Shields
- Canon Stroke and Vascular Research Center, Buffalo, NY 14208
- Department of Medical Physics, University at Buffalo, Buffalo, NY 14228
- University at Buffalo Neurosurgery, University at Buffalo Jacobs School of Medicine, Buffalo, NY 14228
| | - S V Setlur Nagesh
- Canon Stroke and Vascular Research Center, Buffalo, NY 14208
- University at Buffalo Neurosurgery, University at Buffalo Jacobs School of Medicine, Buffalo, NY 14228
| | - Daniel R Bednarek
- Canon Stroke and Vascular Research Center, Buffalo, NY 14208
- Department of Medical Physics, University at Buffalo, Buffalo, NY 14228
- University at Buffalo Neurosurgery, University at Buffalo Jacobs School of Medicine, Buffalo, NY 14228
| | - Stephen Rudin
- Department of Biomedical Engineering, University at Buffalo, Buffalo, NY 14228
- Canon Stroke and Vascular Research Center, Buffalo, NY 14208
- Department of Medical Physics, University at Buffalo, Buffalo, NY 14228
- University at Buffalo Neurosurgery, University at Buffalo Jacobs School of Medicine, Buffalo, NY 14228
| | - Ciprian N Ionita
- Department of Biomedical Engineering, University at Buffalo, Buffalo, NY 14228
- Canon Stroke and Vascular Research Center, Buffalo, NY 14208
- Department of Medical Physics, University at Buffalo, Buffalo, NY 14228
- University at Buffalo Neurosurgery, University at Buffalo Jacobs School of Medicine, Buffalo, NY 14228
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Al-Mubarak HFI, Vallatos A, Holmes WM. Impact of turbulence-induced asymmetric propagators on the accuracy of phase-contrast velocimetry. J Magn Reson 2021; 325:106929. [PMID: 33713991 DOI: 10.1016/j.jmr.2021.106929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 01/14/2021] [Accepted: 01/27/2021] [Indexed: 06/12/2023]
Abstract
Phase-contrast magnetic resonance velocimetry (PC-MRI) has been widely used to investigate flow properties in numerous systems. In a horizontal cylindrical pipe (3 mm diameter), we investigated the accuracy of PC-MRI as the flow transitioned from laminar to turbulent flow (Reynolds number 352-2708). We focus primarily on velocimetry errors introduced by skewed intra-voxel displacement distributions, a consequence of PC-MRI theory assuming symmetric distributions. We demonstrated how rapid fluctuations in the velocity field, can produce broad asymmetric intravoxel displacement distributions near the wall. Depending on the shape of the distribution, this resulted in PC-MRI measurements under-estimating (positive skewness) or over-estimating (negative skewness) the true mean intravoxel velocity, which could have particular importance to clinical wall shear stress measurements. The magnitude of these velocity errors was shown to increase with the variance and decrease with the kurtosis of the intravoxel displacement distribution. These experimental results confirm our previous theoretical analysis, which gives a relationship for PC-MRI velocimetry errors, as a function of the higher moments of the intravoxel displacement distribution (skewness, variance, and kurtosis) and the experimental parameters q and Δ. This suggests that PC-MRI errors in such unsteady/turbulent flow conditions can potentially be reduced by employing lower q values or shorter observation times Δ.
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Affiliation(s)
- Haitham F I Al-Mubarak
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, UK; Department of Physics, College of Science, Misan University, Iraq
| | - Antoine Vallatos
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, UK; Centre for Clinical Brain Sciences, University of Edinburgh, UK
| | - William M Holmes
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, UK.
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Abstract
Throughout their lives, squids are both predators and prey for a multitude of animals, many of which are at the top of ocean food webs, making them an integral component of the trophic structure of marine ecosystems. The escape jet, which is produced by the rapid expulsion of water from the mantle cavity through a funnel, is central to a cephalopod's ability to avoid predation throughout its life. Although squid undergo morphological and behavioral changes and experience remarkably different Reynolds number regimes throughout their development, little is known about the dynamics and propulsive efficiency of escape jets throughout ontogeny. We examine the hydrodynamics and kinematics of escape jets in squid throughout ontogeny using 2D/3D velocimetry and high-speed videography. All life stages of squid produced two escape jet patterns: (1) 'escape jet I' characterized by short rapid pulses resulting in vortex ring formation and (2) 'escape jet II' characterized by long high-volume jets, often with a leading-edge vortex ring. Paralarvae exhibited higher propulsive efficiency than adult squid during escape jet ejection, and propulsive efficiency was higher for escape jet I than escape jet II in juveniles and adults. These results indicate that although squid undergo major ecological transitions and morphology changes from paralarvae to adults, all life stages demonstrate flexibility in escape jet responses and produce escape jets of surprisingly high propulsive efficiency.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Carly A York
- Department of Biology, Lenoir-Rhyne University, Hickory, NC 28601, USA
| | - Ian K Bartol
- Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529, USA
| | - Paul S Krueger
- Department of Mechanical Engineering, Southern Methodist University, Dallas, TX 75275, USA
| | - Joseph T Thompson
- Department of Biology, Franklin and Marshall College, Lancaster, PA 17604, USA
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Huang H, Huang F, Lin L, Feng Z, Cheng Y, Wang Y, Chen D. Perceiving Linear-Velocity by Multiphoton Upconversion. ACS Appl Mater Interfaces 2019; 11:46379-46385. [PMID: 31724844 DOI: 10.1021/acsami.9b17507] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Up to now, the rising edge of the upconversion process does not receive due attention. Herein, a demonstration utilizing the feature of the rising edge to practically detect the linear-velocity of an object is presented. Typically, upconversion processes with different numbers of participant photons would exhibit diversity in the rising edge. On this account, when the emitter is moving, the emission intensity ratio of different multiphoton processes will vary with changing linear-velocity, which enables accurate speed detection through spectral analysis. To illustrate this principle, in this work, the modeling and numerical simulation were first performed, and then experimental demonstration was carried out in which core-shell upconversion nanocrystals were elaborately designed and fabricated as the speed sensing probe to calibrate the speed of a homemade turnplate. It is believed that the present work will exploit a novel speed sensing method and find a new application for lanthanide-doped upconversion materials.
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Affiliation(s)
- Hai Huang
- College of Physics and Energy , Fujian Normal University , Fujian Provincial Key Laboratory of Quantum Manipulation and New Energy Materials, Fuzhou 350117 , China
- Fujian Provincial Engineering Technology Research Center of Solar Energy Conversion and Energy Storage , Fuzhou 350117 , China
- Fujian Provincial Collaborative Innovation Center for Optoelectronic Semiconductors and Efficient Devices , Xiamen 361005 , China
| | - Feng Huang
- College of Physics and Energy , Fujian Normal University , Fujian Provincial Key Laboratory of Quantum Manipulation and New Energy Materials, Fuzhou 350117 , China
- Fujian Provincial Engineering Technology Research Center of Solar Energy Conversion and Energy Storage , Fuzhou 350117 , China
- Fujian Provincial Collaborative Innovation Center for Optoelectronic Semiconductors and Efficient Devices , Xiamen 361005 , China
| | - Lin Lin
- College of Physics and Energy , Fujian Normal University , Fujian Provincial Key Laboratory of Quantum Manipulation and New Energy Materials, Fuzhou 350117 , China
- Fujian Provincial Engineering Technology Research Center of Solar Energy Conversion and Energy Storage , Fuzhou 350117 , China
- Fujian Provincial Collaborative Innovation Center for Optoelectronic Semiconductors and Efficient Devices , Xiamen 361005 , China
| | - Zhuohong Feng
- College of Physics and Energy , Fujian Normal University , Fujian Provincial Key Laboratory of Quantum Manipulation and New Energy Materials, Fuzhou 350117 , China
- Fujian Provincial Engineering Technology Research Center of Solar Energy Conversion and Energy Storage , Fuzhou 350117 , China
- Fujian Provincial Collaborative Innovation Center for Optoelectronic Semiconductors and Efficient Devices , Xiamen 361005 , China
| | - Yao Cheng
- CAS Key Laboratory of Design and Assembly of Functional Nanostructures , Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou , Fujian 350002 , China
| | - Yuansheng Wang
- CAS Key Laboratory of Design and Assembly of Functional Nanostructures , Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou , Fujian 350002 , China
| | - Daqin Chen
- College of Physics and Energy , Fujian Normal University , Fujian Provincial Key Laboratory of Quantum Manipulation and New Energy Materials, Fuzhou 350117 , China
- Fujian Provincial Engineering Technology Research Center of Solar Energy Conversion and Energy Storage , Fuzhou 350117 , China
- Fujian Provincial Collaborative Innovation Center for Optoelectronic Semiconductors and Efficient Devices , Xiamen 361005 , China
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Clarke DA, Fabich HT, Brox TI, Galvosas P, Holland DJ. On the influence of rotational motion on MRI velocimetry of granular flows - Theoretical predictions and comparison to experimental data. J Magn Reson 2019; 307:106569. [PMID: 31472436 DOI: 10.1016/j.jmr.2019.106569] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 08/07/2019] [Accepted: 08/07/2019] [Indexed: 06/10/2023]
Abstract
Continuum dynamics of granular materials are known to be influenced by rotational, as well as translational, motion. Few experimental techniques exist that are sensitive to rotational motion. Here we demonstrate that MRI is sensitive to the rotation of granules and that we can quantify its effect on the MRI signal. In order to demonstrate the importance of rotational motion, we perform discrete element method (DEM) simulations of spherical particles inside a Couette shear cell. The variance of the velocity distribution was determined from DEM data using two approaches. (1) Direct averaging of the individual particle velocities. (2) Numerical simulation of the pulsed field gradient (PFG) MRI signal acquisition based on the DEM data. Rotational motion is found to be a significant effect, typically contributing up to 50% of the signal attenuation, thus amplifying the calculated velocity variance. A theoretical model was derived to relate an MRI signal to the angular velocity distribution. This model for the signal was compared to previously published experimental data as well as simulated MRI results and found to be consistent.
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Affiliation(s)
- Daniel A Clarke
- Department of Chemical and Process Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
| | - Hilary T Fabich
- ABQMR Incorporated, Albuquerque, NM, United States of America; Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge University West Site, Philippa Fawcett Dr, Cambridge CB3 0AS, United Kingdom
| | - Timothy I Brox
- School of Chemical and Physical Sciences, Victoria University of Wellington, PO Box 600, Wellington 6140, New Zealand
| | - Petrik Galvosas
- School of Chemical and Physical Sciences, Victoria University of Wellington, PO Box 600, Wellington 6140, New Zealand
| | - Daniel J Holland
- Department of Chemical and Process Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand.
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Magdoom KN, Zeinomar A, Lonser RR, Sarntinoranont M, Mareci TH. Phase contrast MRI of creeping flows using stimulated echo. J Magn Reson 2019; 299:49-58. [PMID: 30579226 PMCID: PMC6402592 DOI: 10.1016/j.jmr.2018.12.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Revised: 12/10/2018] [Accepted: 12/13/2018] [Indexed: 05/30/2023]
Abstract
Creeping flows govern many important physiological phenomena such as elevated interstitial fluid flows in tumors, glymphatic flows in the brain, among other applications. However, few methods exist to measure such slow flows non-invasively in optically opaque biological tissues in vivo. Phase-contrast MRI is a velocimetry technique routinely used in the clinic to measure fast flows in biological tissues, such as blood and cerebrospinal fluid (CSF), in the order of cm/s. Use of this technique to encode slower flows is hampered by diffusion weighting and phase error introduced by gradient hardware imperfections. In this study, a new PC-MRI technique is developed using stimulated echo preparation to overcome these challenges. Flows as slow as 1 μm/s are measured and validated using controlled water flow through a pipe at 4.7 T. The error in measured flow rate obtained by integrating the measured velocity over the cross-sectional area of the pipe is less than 10%. The developed method was also able to capture slow natural convection flows appearing in liquids placed inside a horizontal bore magnet. Monitoring the 4D velocity vector field revealed that the natural convection flows decay exponentially with time. This method could be applied in future to study creeping flows, e.g. in tissue.
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Affiliation(s)
- Kulam Najmudeen Magdoom
- Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL, USA.
| | - Ahmad Zeinomar
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, USA
| | - Russell R Lonser
- Department of Neurological Surgery, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | - Malisa Sarntinoranont
- Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL, USA; J. Crayton Pruitt Family Department of Biomedical Engineering, 1275 Center Drive, Biomedical Sciences Building, Gainesville, FL, USA
| | - Thomas H Mareci
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, USA; J. Crayton Pruitt Family Department of Biomedical Engineering, 1275 Center Drive, Biomedical Sciences Building, Gainesville, FL, USA
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Vallatos A, Al-Mubarak HFI, Mullin JM, Holmes WM. Accuracy of phase-contrast velocimetry in systems with skewed intravoxel velocity distributions. J Magn Reson 2018; 296:121-129. [PMID: 30245475 DOI: 10.1016/j.jmr.2018.09.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 09/03/2018] [Accepted: 09/04/2018] [Indexed: 06/08/2023]
Abstract
Phase contrast velocimetry (PCV) has been widely used to investigate flow properties in numerous systems. Several authors have reported errors in velocity measurements and have speculated on the sources, which have ranged from eddy current effects to acceleration artefacts. An often overlooked assumption in the theory of PCV, which may not be met in complex or unsteady flows, is that the intravoxel displacement distributions (propagators) are symmetric. Here, the effect of the higher moments of the displacement distribution (variance, skewness and kurtosis) on the accuracy of PCV is investigated experimentally and theoretically. Phase and propagator measurements are performed on tailored intravoxel distributions, achieved using a simple phantom combined with a single large voxel. Asymmetric distributions (Skewness ≠ 0) are shown to generate important phase measurement errors that lead to significant velocimetry errors. Simulations of the phase of the spin vector sum, based on experimentally measured propagators, are shown to quantitatively reproduce the relationship between measured phase and experimental parameters. These allow relating the observed velocimetry errors to a discrepancy between the average phase of intravoxel spins considered in PCV theory and the vector phase actually measured by a PFG experiment. A theoretical expression is derived for PCV velocimetry errors as a function of the moments of the displacement distribution. Positively skewed distributions result in an underestimation of the true mean velocity, while negatively skewed distributions result in an overestimation. The magnitude of these errors is shown to increase with the variance and decrease with the kurtosis of the intravoxel displacement distribution.
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Affiliation(s)
- Antoine Vallatos
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, UK; Centre for Clinical Brain Sciences, University of Edinburgh, UK
| | - Haitham F I Al-Mubarak
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, UK
| | - James M Mullin
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, UK
| | - William M Holmes
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, UK.
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Shukla MN, Vallatos A, Phoenix VR, Holmes WM. Accurate phase-shift velocimetry in rock. J Magn Reson 2016; 267:43-53. [PMID: 27111139 DOI: 10.1016/j.jmr.2016.04.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 04/11/2016] [Accepted: 04/12/2016] [Indexed: 06/05/2023]
Abstract
Spatially resolved Pulsed Field Gradient (PFG) velocimetry techniques can provide precious information concerning flow through opaque systems, including rocks. This velocimetry data is used to enhance flow models in a wide range of systems, from oil behaviour in reservoir rocks to contaminant transport in aquifers. Phase-shift velocimetry is the fastest way to produce velocity maps but critical issues have been reported when studying flow through rocks and porous media, leading to inaccurate results. Combining PFG measurements for flow through Bentheimer sandstone with simulations, we demonstrate that asymmetries in the molecular displacement distributions within each voxel are the main source of phase-shift velocimetry errors. We show that when flow-related average molecular displacements are negligible compared to self-diffusion ones, symmetric displacement distributions can be obtained while phase measurement noise is minimised. We elaborate a complete method for the production of accurate phase-shift velocimetry maps in rocks and low porosity media and demonstrate its validity for a range of flow rates. This development of accurate phase-shift velocimetry now enables more rapid and accurate velocity analysis, potentially helping to inform both industrial applications and theoretical models.
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Affiliation(s)
- Matsyendra Nath Shukla
- School of Geographical and Earth Sciences, University of Glasgow, United Kingdom; Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, United Kingdom
| | - Antoine Vallatos
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, United Kingdom.
| | - Vernon R Phoenix
- School of Geographical and Earth Sciences, University of Glasgow, United Kingdom
| | - William M Holmes
- Glasgow Experimental MRI Centre, Institute of Neuroscience and Psychology, University of Glasgow, United Kingdom
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Kuczera S, Galvosas P. Advances and artefact suppression in RARE- velocimetry for flow with curved streamlines. J Magn Reson 2015; 259:135-145. [PMID: 26340434 DOI: 10.1016/j.jmr.2015.07.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 07/13/2015] [Accepted: 07/17/2015] [Indexed: 06/05/2023]
Abstract
Method and considerations are presented that allow for an improved quantitative velocity measurement of complex fluids under shear using a fast 2D PGSE-RARE technique. While this contribution is relevant for shear geometries with rotational symmetry in general, the focus here is set on cylindrical Couette cells, a device most commonly used for rheological NMR investigations. The curved nature of the flow within the shearing geometry creates challenges in accurately determining the flow profile, as conventional imaging gradients naturally operate on a Cartesian grid. In particular the appropriate slice thickness in the flow direction and the applied k-space trajectory are discussed. For the latter an MRI simulation program has been written that numerically solves the Bloch equations and allows for the investigation of out-of-pixel flow. Furthermore, we present ways of increasing the spatial resolution across the gap of cylindrical Couette cells while still providing 2D imaging capabilities under certain conditions, thus allowing for a more detailed quantification of flow profiles as necessary for the analysis of complex fluid flow.
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Affiliation(s)
- Stefan Kuczera
- MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand
| | - Petrik Galvosas
- MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand.
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Abstract
Within its life cycle, a copepod goes through drastic changes in size, shape and swimming mode. In particular, there is a stark difference between the early (nauplius) and later (copepodid) stages. Copepods inhabit an intermediate Reynolds number regime (between ~1 and 100) where both viscosity and inertia are potentially important, and the Reynolds number changes by an order of magnitude during growth. Thus we expect the life stage related changes experienced by a copepod to result in hydrodynamic and energetic differences, ultimately affecting the fitness. To quantify these differences, we measured the swimming kinematics and fluid flow around jumping Acartia tonsa at different stages of its life cycle, using particle image velocimetry and particle tracking velocimetry. We found that the flow structures around nauplii and copepodids are topologically different, with one and two vortex rings, respectively. Our measurements suggest that copepodids cover a larger distance compared to their body size in each jump and are also hydrodynamically quieter, as the flow disturbance they create attenuates faster with distance. Also, copepodids are energetically more efficient than nauplii, presumably due to the change in hydrodynamic regime accompanied with a well-adapted body form and swimming stroke.
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Affiliation(s)
- Navish Wadhwa
- Department of Physics and Centre for Ocean Life, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Anders Andersen
- Department of Physics and Centre for Ocean Life, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Thomas Kiørboe
- National Institute for Aquatic Resources and Centre for Ocean Life, Technical University of Denmark, DK-2920 Charlottenlund, Denmark
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