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Rivera-Rivera LA, Vikner T, Eisenmenger L, Johnson SC, Johnson KM. Four-dimensional flow MRI for quantitative assessment of cerebrospinal fluid dynamics: Status and opportunities. NMR IN BIOMEDICINE 2024; 37:e5082. [PMID: 38124351 PMCID: PMC11162953 DOI: 10.1002/nbm.5082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 10/03/2023] [Accepted: 11/07/2023] [Indexed: 12/23/2023]
Abstract
Neurological disorders can manifest with altered neurofluid dynamics in different compartments of the central nervous system. These include alterations in cerebral blood flow, cerebrospinal fluid (CSF) flow, and tissue biomechanics. Noninvasive quantitative assessment of neurofluid flow and tissue motion is feasible with phase contrast magnetic resonance imaging (PC MRI). While two-dimensional (2D) PC MRI is routinely utilized in research and clinical settings to assess flow dynamics through a single imaging slice, comprehensive neurofluid dynamic assessment can be limited or impractical. Recently, four-dimensional (4D) flow MRI (or time-resolved three-dimensional PC with three-directional velocity encoding) has emerged as a powerful extension of 2D PC, allowing for large volumetric coverage of fluid velocities at high spatiotemporal resolution within clinically reasonable scan times. Yet, most 4D flow studies have focused on blood flow imaging. Characterizing CSF flow dynamics with 4D flow (i.e., 4D CSF flow) is of high interest to understand normal brain and spine physiology, but also to study neurological disorders such as dysfunctional brain metabolite waste clearance, where CSF dynamics appear to play an important role. However, 4D CSF flow imaging is challenged by the long T1 time of CSF and slower velocities compared with blood flow, which can result in longer scan times from low flip angles and extended motion-sensitive gradients, hindering clinical adoption. In this work, we review the state of 4D CSF flow MRI including challenges, novel solutions from current research and ongoing needs, examples of clinical and research applications, and discuss an outlook on the future of 4D CSF flow.
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Affiliation(s)
- Leonardo A Rivera-Rivera
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Tomas Vikner
- Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Department of Radiation Sciences, Radiation Physics and Biomedical Engineering, Umeå University, Umeå, Sweden
| | - Laura Eisenmenger
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Sterling C Johnson
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Kevin M Johnson
- Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
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Rothenberger SM, Patel NM, Zhang J, Schnell S, Craig BA, Ansari SA, Markl M, Vlachos PP, Rayz VL. Automatic 4D Flow MRI Segmentation Using the Standardized Difference of Means Velocity. IEEE TRANSACTIONS ON MEDICAL IMAGING 2023; 42:2360-2373. [PMID: 37028010 PMCID: PMC10474251 DOI: 10.1109/tmi.2023.3251734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
We present a method to automatically segment 4D flow magnetic resonance imaging (MRI) by identifying net flow effects using the standardized difference of means (SDM) velocity. The SDM velocity quantifies the ratio between the net flow and observed flow pulsatility in each voxel. Vessel segmentation is performed using an F-test, identifying voxels with significantly higher SDM velocity values than background voxels. We compare the SDM segmentation algorithm against pseudo-complex difference (PCD) intensity segmentation of 4D flow measurements in in vitro cerebral aneurysm models and 10 in vitro Circle of Willis (CoW) datasets. We also compared the SDM algorithm to convolutional neural network (CNN) segmentation in 5 thoracic vasculature datasets. The in vitro flow phantom geometry is known, while the ground truth geometries for the CoW and thoracic aortas are derived from high-resolution time-of-flight (TOF) magnetic resonance angiography and manual segmentation, respectively. The SDM algorithm demonstrates greater robustness than PCD and CNN approaches and can be applied to 4D flow data from other vascular territories. The SDM to PCD comparison demonstrated an approximate 48% increase in sensitivity in vitro and 70% increase in the CoW, respectively; the SDM and CNN sensitivities were similar. The vessel surface derived from the SDM method was 46% closer to the in vitro surfaces and 72% closer to the in vitro TOF surfaces than the PCD approach. The SDM and CNN approaches both accurately identify vessel surfaces. The SDM algorithm is a repeatable segmentation method, enabling reliable computation of hemodynamic metrics associated with cardiovascular disease.
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3
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Srinivas S, Masutani E, Norbash A, Hsiao A. Deep learning phase error correction for cerebrovascular 4D flow MRI. Sci Rep 2023; 13:9095. [PMID: 37277401 DOI: 10.1038/s41598-023-36061-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 05/29/2023] [Indexed: 06/07/2023] Open
Abstract
Background phase errors in 4D Flow MRI may negatively impact blood flow quantification. In this study, we assessed their impact on cerebrovascular flow volume measurements, evaluated the benefit of manual image-based correction, and assessed the potential of a convolutional neural network (CNN), a form of deep learning, to directly infer the correction vector field. With IRB waiver of informed consent, we retrospectively identified 96 MRI exams from 48 patients who underwent cerebrovascular 4D Flow MRI from October 2015 to 2020. Flow measurements of the anterior, posterior, and venous circulation were performed to assess inflow-outflow error and the benefit of manual image-based phase error correction. A CNN was then trained to directly infer the phase-error correction field, without segmentation, from 4D Flow volumes to automate correction, reserving from 23 exams for testing. Statistical analyses included Spearman correlation, Bland-Altman, Wilcoxon-signed rank (WSR) and F-tests. Prior to correction, there was strong correlation between inflow and outflow (ρ = 0.833-0.947) measurements with the largest discrepancy in the venous circulation. Manual phase error correction improved inflow-outflow correlation (ρ = 0.945-0.981) and decreased variance (p < 0.001, F-test). Fully automated CNN correction was non-inferior to manual correction with no significant differences in correlation (ρ = 0.971 vs ρ = 0.982) or bias (p = 0.82, Wilcoxon-Signed Rank test) of inflow and outflow measurements. Residual background phase error can impair inflow-outflow consistency of cerebrovascular flow volume measurements. A CNN can be used to directly infer the phase-error vector field to fully automate phase error correction.
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Affiliation(s)
- Shanmukha Srinivas
- Department of Radiology, University of California San Diego, 200 West Arbor Drive, San Diego, CA, 92103, USA
- Department of Radiology, University of California Los Angeles, 757 Westwood Plaza, Los Angeles, CA, 90095, USA
| | - Evan Masutani
- Department of Radiology, University of California San Diego, 200 West Arbor Drive, San Diego, CA, 92103, USA
| | - Alexander Norbash
- Department of Radiology, University of California San Diego, 200 West Arbor Drive, San Diego, CA, 92103, USA
| | - Albert Hsiao
- Department of Radiology, University of California San Diego, 200 West Arbor Drive, San Diego, CA, 92103, USA.
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Saitta S, Maga L, Armour C, Votta E, O'Regan DP, Salmasi MY, Athanasiou T, Weinsaft JW, Xu XY, Pirola S, Redaelli A. Data-driven generation of 4D velocity profiles in the aneurysmal ascending aorta. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2023; 233:107468. [PMID: 36921465 DOI: 10.1016/j.cmpb.2023.107468] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 02/15/2023] [Accepted: 03/05/2023] [Indexed: 06/18/2023]
Abstract
BACKGROUND AND OBJECTIVE Numerical simulations of blood flow are a valuable tool to investigate the pathophysiology of ascending thoratic aortic aneurysms (ATAA). To accurately reproduce in vivo hemodynamics, computational fluid dynamics (CFD) models must employ realistic inflow boundary conditions (BCs). However, the limited availability of in vivo velocity measurements, still makes researchers resort to idealized BCs. The aim of this study was to generate and thoroughly characterize a large dataset of synthetic 4D aortic velocity profiles sampled on a 2D cross-section along the ascending aorta with features similar to clinical cohorts of patients with ATAA. METHODS Time-resolved 3D phase contrast magnetic resonance (4D flow MRI) scans of 30 subjects with ATAA were processed through in-house code to extract anatomically consistent cross-sectional planes along the ascending aorta, ensuring spatial alignment among all planes and interpolating all velocity fields to a reference configuration. Velocity profiles of the clinical cohort were extensively characterized by computing flow morphology descriptors of both spatial and temporal features. By exploiting principal component analysis (PCA), a statistical shape model (SSM) of 4D aortic velocity profiles was built and a dataset of 437 synthetic cases with realistic properties was generated. RESULTS Comparison between clinical and synthetic datasets showed that the synthetic data presented similar characteristics as the clinical population in terms of key morphological parameters. The average velocity profile qualitatively resembled a parabolic-shaped profile, but was quantitatively characterized by more complex flow patterns which an idealized profile would not replicate. Statistically significant correlations were found between PCA principal modes of variation and flow descriptors. CONCLUSIONS We built a data-driven generative model of 4D aortic inlet velocity profiles, suitable to be used in computational studies of blood flow. The proposed software system also allows to map any of the generated velocity profiles to the inlet plane of any virtual subject given its coordinate set.
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Affiliation(s)
- Simone Saitta
- Department of Information, Electronics and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Ludovica Maga
- Department of Information, Electronics and Bioengineering, Politecnico di Milano, Milan, Italy; Department of Chemical Engineering, Imperial College London, London, UK
| | - Chloe Armour
- Department of Chemical Engineering, Imperial College London, London, UK
| | - Emiliano Votta
- Department of Information, Electronics and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Declan P O'Regan
- MRC London Institute of Medical Sciences, Imperial College London, London, United Kingdom
| | - M Yousuf Salmasi
- Department of Surgery and Cancer, Imperial College London, London, United Kingdom
| | - Thanos Athanasiou
- Department of Surgery and Cancer, Imperial College London, London, United Kingdom
| | - Jonathan W Weinsaft
- Department of Medicine (Cardiology), Weill Cornell College, New York, NY, USA
| | - Xiao Yun Xu
- Department of Chemical Engineering, Imperial College London, London, UK
| | - Selene Pirola
- Department of Chemical Engineering, Imperial College London, London, UK; Department of BioMechanical Engineering, 3mE Faculty, Delft University of Technology, Delft, Netherlands.
| | - Alberto Redaelli
- Department of Information, Electronics and Bioengineering, Politecnico di Milano, Milan, Italy
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Sache A, Reymond P, Brina O, Jung B, Farhat M, Vargas MI. Near-wall hemodynamic parameters quantification in in vitro intracranial aneurysms with 7 T PC-MRI. MAGMA (NEW YORK, N.Y.) 2023; 36:295-308. [PMID: 37072539 PMCID: PMC10140017 DOI: 10.1007/s10334-023-01082-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 03/20/2023] [Accepted: 03/21/2023] [Indexed: 04/20/2023]
Abstract
OBJECTIVE Wall shear stress (WSS) and its derived spatiotemporal parameters have proven to play a major role on intracranial aneurysms (IAs) growth and rupture. This study aims to demonstrate how ultra-high field (UHF) 7 T phase contrast magnetic resonance imaging (PC-MRI) coupled with advanced image acceleration techniques allows a highly resolved visualization of near-wall hemodynamic parameters patterns in in vitro IAs, paving the way for more robust risk assessment of their growth and rupture. MATERIALS AND METHODS We performed pulsatile flow measurements inside three in vitro models of patient-specific IAs using 7 T PC-MRI. To this end, we built an MRI-compatible test bench, which faithfully reproduced a typical physiological intracranial flow rate in the models. RESULTS The ultra-high field 7 T images revealed WSS patterns with high spatiotemporal resolution. Interestingly, the high oscillatory shear index values were found in the core of low WSS vortical structures and in flow stream intersecting regions. In contrast, maxima of WSS occurred around the impinging jet sites. CONCLUSIONS We showed that the elevated signal-to-noise ratio arising from 7 T PC-MRI enabled to resolve high and low WSS patterns with a high degree of detail.
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Affiliation(s)
- Antoine Sache
- Department of Mechanical Engineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
| | - Philippe Reymond
- Division of Neuroradiology, Geneva University Hospital, University of Geneva, Geneva, Switzerland
| | - Olivier Brina
- Division of Neuroradiology, Geneva University Hospital, University of Geneva, Geneva, Switzerland
| | - Bernd Jung
- Department of Diagnostic, Interventional and Paediatric Radiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Mohamed Farhat
- Department of Mechanical Engineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Maria Isabel Vargas
- Division of Neuroradiology, Geneva University Hospital, University of Geneva, Geneva, Switzerland
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Jonnagiri R, Sundström E, Gutmark E, Anderson S, Pednekar AS, Taylor MD, Tretter JT, Gutmark-Little I. Influence of aortic valve morphology on vortical structures and wall shear stress. Med Biol Eng Comput 2023; 61:1489-1506. [PMID: 36763231 DOI: 10.1007/s11517-023-02790-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 01/19/2023] [Indexed: 02/11/2023]
Abstract
The aim of this paper is to assess the association between valve morphology and vortical structures quantitatively and to highlight the influence of valve morphology/orientation on aorta's susceptibility to shear stress, both proximal and distal. Four-dimensional phase-contrast magnetic resonance imaging (4D PCMRI) data of 6 subjects, 3 with tricuspid aortic valve (TAV) and 3 with functionally bicuspid aortic values (BAV) with right-left coronary leaflet fusion, were processed and analyzed for vorticity and wall shear stress trends. Computational fluid dynamics (CFD) has been used with moving TAV and BAV valve designs in patient-specific aortae to compare with in vivo shear stress data. Vorticity from 4D PCMRI data about the aortic centerline demonstrated that TAVs had a higher number of vortical flow structures than BAVs at peak systole. Coalescing of flow structures was shown to be possible in the arch region of all subjects. Wall shear stress (WSS) distribution from CFD results at the aortic root is predominantly symmetric for TAVs but highly asymmetric for BAVs with the region opposite the raphe (fusion location of underdeveloped leaflets) being subjected to higher WSS. Asymmetry in the size and number of leaflets in BAVs and TAVs significantly influence vortical structures and WSS in the proximal aorta for all valve types and distal aorta for certain valve orientations of BAV. Analysis of vortical structures using 4D PCMRI data (on the left side) and wall shear stress data using CFD (on the right side).
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Affiliation(s)
- Raghuvir Jonnagiri
- Department of Aerospace Engineering and Engineering Mechanics, University of Cincinnati, Cincinnati, OH, 45221, USA.
| | - Elias Sundström
- Department of Engineering Mechanics, Royal Institute of Technology, 10044, Stockholm, Sweden
| | - Ephraim Gutmark
- Department of Aerospace Engineering and Engineering Mechanics, University of Cincinnati, Cincinnati, OH, 45221, USA
| | - Shae Anderson
- Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Amol S Pednekar
- Division of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Michael D Taylor
- Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA.,Department of Pediatrics, University of Cincinnati, Cincinnati, OH, 45267, USA
| | - Justin T Tretter
- Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA.,Department of Pediatrics, University of Cincinnati, Cincinnati, OH, 45267, USA
| | - Iris Gutmark-Little
- Department of Pediatrics, University of Cincinnati, Cincinnati, OH, 45267, USA.,Division of Endocrinology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
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7
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van den Kerkhof M, Jansen JFA, van Oostenbrugge RJ, Backes WH. 1D versus 3D blood flow velocity and pulsatility measurements of lenticulostriate arteries at 7T MRI. Magn Reson Imaging 2023; 96:144-150. [PMID: 36473545 DOI: 10.1016/j.mri.2022.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 11/21/2022] [Accepted: 12/01/2022] [Indexed: 12/12/2022]
Abstract
PURPOSE 7T MRI enables measurements of blood flow velocity waveforms in small, perforating cerebral arteries. As these vessels can be tortuous, acquisition methods sensitive to flow in only one direction may not be sufficient to accurately determine the dynamic blood flow velocity. In this study, we compared 1D with 3D velocity encoding to measure the blood flow velocity and pulsatility in the lenticulostriate arteries (LSAs). METHODS Blood flow velocity waveforms were measured in the LSAs of 18 subjects (age range: 20-74 years) using prospectively gated single-slice phase contrast (PC) MRI at 7T. For each subject, blood flow velocity waveforms were acquired in a single slice with one velocity encoding as well as three orthogonal velocity encodings. The peak velocity and pulsatility index (PI) were determined in the largest, perpendicularly planned LSA, one obliquely planned LSA and three smaller LSAs. The peak velocity and PI were compared between 1D and 3D measurements using Bland-Altman analysis, with the 95% limits of agreement (LOA) taken into account. RESULTS For the largest, perpendicularly planned LSA, the peak velocity was slightly lower (0.2 cm/s, 1.7%) for 1D compared to 3D measurements, with an LOA range from the mean difference of (-0.27;0.27). The PI was slightly higher (0.01, 1.6%) for the 1D measurement, and an LOA range from the mean difference in PI of (-0.045;0.045). The obliquely planned LSA and three smaller LSAs demonstrated larger deviations (range mean percentage difference: 3.9-8.2%). CONCLUSION 1D velocity encoding using 2D PC MRI provides sufficiently accurate dynamic velocity and pulsatility measurements in slices perpendicularly planned to single, large LSAs compared to 3D velocity encoding, while increasing errors are obtained with obliquely planned slices. A greater error is indicated when measuring multiple (possibly tortuous or obliquely planned) smaller LSAs in one scan using one-directional single-slice PC MRI.
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Affiliation(s)
- Marieke van den Kerkhof
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, PO Box 5800, 6202 AZ Maastricht, the Netherlands; School for Mental Health and Neuroscience, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands
| | - Jacobus F A Jansen
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, PO Box 5800, 6202 AZ Maastricht, the Netherlands; School for Mental Health and Neuroscience, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands; Department of Electrical Engineering, University of Eindhoven, PO Box 513, 5600 MB Eindhoven, the Netherlands
| | - Robert J van Oostenbrugge
- School for Mental Health and Neuroscience, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands; Department of Neurology, Maastricht University Medical Center, PO Box 5800, 6202 AZ Maastricht, the Netherlands; School for Cardiovascular Diseases, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands
| | - Walter H Backes
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, PO Box 5800, 6202 AZ Maastricht, the Netherlands; School for Mental Health and Neuroscience, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands; School for Cardiovascular Diseases, Maastricht University, PO Box 616, 6200 MD Maastricht, the Netherlands.
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8
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Roos PR, Rijnberg FM, Westenberg JJM, Lamb HJ. Particle Tracing Based on
4D
Flow Magnetic Resonance Imaging: A Systematic Review into Methods, Applications, and Current Developments. J Magn Reson Imaging 2022; 57:1320-1339. [PMID: 36484213 DOI: 10.1002/jmri.28540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 11/15/2022] [Accepted: 11/15/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Particle tracing based on 4D Flow MRI has been applied as a quantitative and qualitative postprocessing technique to study temporally evolving blood flow patterns. PURPOSE To systematically review the various methods to perform 4D Flow MRI-based particle tracing, as well as the clinical value, clinical applications, and current developments of the technique. STUDY TYPE The study type is systematic review. SUBJECTS Patients with cardiovascular disease (such as Marfan, Fontan, Tetralogy of Fallot), healthy controls, and cardiovascular phantoms that received 4D Flow MRI with particle tracing. FIELD STRENGTH/SEQUENCE Three-dimensional three-directional cine phase-contrast MRI, at 1.5 T and 3 T. ASSESSMENT Two systematic searches were performed on the PubMed database using Boolean operators and the relevant key terms covering 4D Flow MRI and particle tracing. One systematic search was focused on particle tracing methods, whereas the other on applications. Additional articles from other sources were sought out and included after a similar inspection. Particle tracing methods, clinical applications, clinical value, and current developments were extracted. STATISTICAL TESTS The main results of the included studies are summarized, without additional statistical analysis. RESULTS Of 127 unique articles retrieved from the initial search, 56 were included (28 for methods and 54 for applications). Most articles that described particle tracing methods used an adaptive timestep, a fourth order Runge-Kutta integration method, and linear interpolation in the time dimension. Particle tracing was applied in heart chambers, aorta, venae cavae, Fontan circulation, pulmonary arteries, abdominal vasculature, peripheral arteries, carotid arteries, and cerebral vasculature. Applications were grouped as intravascular, intracardiac, flow stasis, and research. DATA CONCLUSIONS Particle tracing based on 4D Flow MRI gives unique insight into blood flow in several cardiovascular diseases, but the quality depends heavily on the MRI data quality. Further studies are required to evaluate the clinical value of the technique for different cardiovascular diseases. EVIDENCE LEVEL 5. TECHNICAL EFFICACY Stage 1.
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Affiliation(s)
- Paul R. Roos
- Department of Radiology Leiden University Medical Center Leiden The Netherlands
| | - Friso M. Rijnberg
- Department of Cardiothoracic Surgery Leiden University Medical Center Leiden The Netherlands
| | | | - Hildo J. Lamb
- Department of Radiology Leiden University Medical Center Leiden The Netherlands
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Garreau M, Puiseux T, Toupin S, Giese D, Mendez S, Nicoud F, Moreno R. Accelerated sequences of 4D flow MRI using GRAPPA and compressed sensing: A comparison against conventional MRI and computational fluid dynamics. Magn Reson Med 2022; 88:2432-2446. [PMID: 36005271 DOI: 10.1002/mrm.29404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 06/30/2022] [Accepted: 07/14/2022] [Indexed: 01/07/2023]
Abstract
PURPOSE To evaluate hemodynamic markers obtained by accelerated GRAPPA (R = 2, 3, 4) and compressed sensing (R = 7.6) 4D flow MRI sequences under complex flow conditions. METHODS The accelerated 4D flow MRI scans were performed on a pulsatile flow phantom, along with a nonaccelerated fully sampled k-space acquisition. Computational fluid dynamics simulations based on the experimentally measured flow fields were conducted for additional comparison. Voxel-wise comparisons (Bland-Altman analysis, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics> <mml:mrow><mml:msub><mml:mi>L</mml:mi> <mml:mn>2</mml:mn></mml:msub> </mml:mrow> <mml:annotation>$$ {L}_2 $$</mml:annotation></mml:semantics> </mml:math> -norm metric), as well as nonderived quantities (velocity profiles, flow rates, and peak velocities), were used to compare the velocity fields obtained from the different modalities. RESULTS 4D flow acquisitions and computational fluid dynamics depicted similar hemodynamic patterns. Voxel-wise comparisons between the MRI scans highlighted larger discrepancies at the voxels located near the phantom's boundary walls. A trend for all MR scans to overestimate velocity profiles and peak velocities as compared to computational fluid dynamics was noticed in regions associated with high velocity or acceleration. However, good agreement for the flow rates was observed, and eddy-current correction appeared essential for consistency of the flow rates measurements with respect to the principle of mass conservation. CONCLUSION GRAPPA (R = 2, 3) and highly accelerated compressed sensing showed good agreement with the fully sampled acquisition. Yet, all 4D flow MRI scans were hampered by artifacts inherent to the phase-contrast acquisition procedure. Computational fluid dynamics simulations are an interesting tool to assess these differences but are sensitive to modeling parameters.
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Affiliation(s)
- Morgane Garreau
- University of Montpellier, CNRS, Montpellier, France.,Spin Up, ALARA Group, Strasbourg, France
| | - Thomas Puiseux
- Spin Up, ALARA Group, Strasbourg, France.,I2MC, INSERM/UPS UMR 1297, Toulouse, France
| | | | - Daniel Giese
- Magnetic Resonance, Siemens Healthcare GmbH, Erlangen, Germany
| | - Simon Mendez
- University of Montpellier, CNRS, Montpellier, France
| | - Franck Nicoud
- University of Montpellier, CNRS, Montpellier, France
| | - Ramiro Moreno
- I2MC, INSERM/UPS UMR 1297, Toulouse, France.,ALARA Expertise, ALARA Group, Strasbourg, France
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10
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Blind image quality assessment of magnetic resonance images with statistics of local intensity extrema. Inf Sci (N Y) 2022. [DOI: 10.1016/j.ins.2022.05.061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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11
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Bracamonte JH, Saunders SK, Wilson JS, Truong UT, Soares JS. Patient-Specific Inverse Modeling of In Vivo Cardiovascular Mechanics with Medical Image-Derived Kinematics as Input Data: Concepts, Methods, and Applications. APPLIED SCIENCES-BASEL 2022; 12:3954. [PMID: 36911244 PMCID: PMC10004130 DOI: 10.3390/app12083954] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Inverse modeling approaches in cardiovascular medicine are a collection of methodologies that can provide non-invasive patient-specific estimations of tissue properties, mechanical loads, and other mechanics-based risk factors using medical imaging as inputs. Its incorporation into clinical practice has the potential to improve diagnosis and treatment planning with low associated risks and costs. These methods have become available for medical applications mainly due to the continuing development of image-based kinematic techniques, the maturity of the associated theories describing cardiovascular function, and recent progress in computer science, modeling, and simulation engineering. Inverse method applications are multidisciplinary, requiring tailored solutions to the available clinical data, pathology of interest, and available computational resources. Herein, we review biomechanical modeling and simulation principles, methods of solving inverse problems, and techniques for image-based kinematic analysis. In the final section, the major advances in inverse modeling of human cardiovascular mechanics since its early development in the early 2000s are reviewed with emphasis on method-specific descriptions, results, and conclusions. We draw selected studies on healthy and diseased hearts, aortas, and pulmonary arteries achieved through the incorporation of tissue mechanics, hemodynamics, and fluid-structure interaction methods paired with patient-specific data acquired with medical imaging in inverse modeling approaches.
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Affiliation(s)
- Johane H. Bracamonte
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Sarah K. Saunders
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - John S. Wilson
- Department of Biomedical Engineering and Pauley Heart Center, Virginia Commonwealth University, Richmond, VA 23219, USA
| | - Uyen T. Truong
- Department of Pediatrics, School of Medicine, Children’s Hospital of Richmond at Virginia Commonwealth University, Richmond, VA 23219, USA
| | - Joao S. Soares
- Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA
- Correspondence:
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12
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Li J, Pei M, Bo B, Zhao X, Cang J, Fang F, Liang Z. Whole-brain mapping of mouse CSF flow via HEAP-METRIC phase-contrast MRI. Magn Reson Med 2022; 87:2851-2861. [PMID: 35107833 PMCID: PMC9305925 DOI: 10.1002/mrm.29179] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 01/06/2022] [Accepted: 01/10/2022] [Indexed: 11/17/2022]
Abstract
Purpose CSF plays important roles in clearing brain waste and homeostasis. However, mapping whole‐brain CSF flow in the rodents is difficult, primarily due to its assumed very low velocity. Therefore, we aimed to develop a novel phase‐contrast MRI method to map whole‐brain CSF flow in the mouse brain. Methods A novel generalized Hadamard encoding–based multi‐band scheme (dubbed HEAP‐METRIC, Hadamard Encoding APproach of Multi‐band Excitation for short TR Imaging aCcelerating) using complex Hadamard matrix was developed and incorporated into conventional phase contrast (PC)‐MRI to significantly increase SNR. Results Slow flow phantom imaging validated HEAP‐METRIC PC‐MRI’s ability to achieve fast and accurate mapping of slow flow velocities (~102 µm/s). With the SNR gain afforded by HEAP‐METRIC scheme, high‐resolution (0.08 × 0.08 mm in‐plane resolution and 36 0.4 mm slices) PC‐MRI was completed in 21 min for whole‐brain CSF flow mapping in the mouse. Using this novel method, we provide the first report of whole‐brain CSF flow in the awake mouse brain with an average flow velocity of ~200 µm/s. Furthermore, HEAP‐METRIC PC‐MRI revealed CSF flow was reduced by isoflurane anesthesia, accompanied by reduction of glymphatic function as measured by dynamic contrast‐enhanced MRI. Conclusion We developed and validated a generalized HEAP‐METRIC PC‐MRI for mapping low velocity flow. With this method, we have achieved the first whole‐brain mapping of awake mouse CSF flow and have further revealed that anesthesia reduces CSF flow velocity.
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Affiliation(s)
- Juchen Li
- Department of Anesthesia, Zhongshan Hospital, Fudan University, Shanghai, People's Republic of China.,Institute of Neuroscience, CAS Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, People's Republic of China
| | - Mengchao Pei
- Institute of Neuroscience, CAS Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, People's Republic of China
| | - Binshi Bo
- Institute of Neuroscience, CAS Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, People's Republic of China
| | - Xinxin Zhao
- Department of Radiology, Shanghai Cancer Institute, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Jing Cang
- Department of Anesthesia, Zhongshan Hospital, Fudan University, Shanghai, People's Republic of China
| | - Fang Fang
- Department of Anesthesia, Zhongshan Hospital, Fudan University, Shanghai, People's Republic of China
| | - Zhifeng Liang
- Institute of Neuroscience, CAS Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, People's Republic of China.,Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai, People's Republic of China
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13
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Yavuz Ilik S, Otani T, Yamada S, Watanabe Y, Wada S. A subject-specific assessment of measurement errors and their correction in cerebrospinal fluid velocity maps using 4D flow MRI. Magn Reson Med 2021; 87:2412-2423. [PMID: 34866235 DOI: 10.1002/mrm.29111] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 11/17/2021] [Accepted: 11/17/2021] [Indexed: 11/05/2022]
Abstract
PURPOSE Phase-contrast MRI (PC-MRI) of cerebrospinal fluid (CSF) velocity is used to evaluate the characteristics of intracranial diseases, such as normal-pressure hydrocephalus (NPH). Nevertheless, PC-MRI has several potential error sources, with eddy-current-based phase offset error being non-negligible in CSF measurement. In this study, we assess the measurement error of CSF velocity maps obtained using 4D flow MRI and evaluate correction methods. METHODS CSF velocity maps of 10 patients with NPH were acquired using 4D flow MRI (velocity-encoding = 5 cm/s). Distributed phase offset error was estimated for a whole 3D background field by polynomial fitting using robust regression analysis. This estimated phase offset error was then used to correct the CSF velocity maps. The estimated error profiles were compared with those obtained using an existing 2D correction approach involving local background information near the region of interest. RESULTS The residual standard error of the polynomial fitting against the phase offset error extracted from the measured velocities was within 0.2 cm/s. The spatial dependencies of the phase offset errors showed similar tendencies in all cases, but sufficient differences in these values were found to indicate requirement of velocity correction. Differences of the estimated errors among other correction approaches were in the order of 10-2 cm/s, and the estimated errors were in good agreement with those obtained using existing approaches. CONCLUSION Our method is capable of estimating the measurement error of CSF velocity maps obtained from 4D flow MRI and provides quantitatively reasonable characteristics for the main CSF profile in the cerebral aqueduct in patients with NPH.
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Affiliation(s)
- Selin Yavuz Ilik
- Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan
| | - Tomohiro Otani
- Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan
| | - Shigeki Yamada
- Department of Neurosurgery, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Yoshiyuki Watanabe
- Department of Radiology, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Shigeo Wada
- Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan
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14
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Zhang Z, Karasan E, Gopalan K, Liu C, Lustig M. DiSpect: Displacement spectrum imaging of flow and tissue perfusion using spin-labeling and stimulated echoes. Magn Reson Med 2021; 86:2468-2481. [PMID: 34096098 DOI: 10.1002/mrm.28882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 05/12/2021] [Accepted: 05/13/2021] [Indexed: 11/09/2022]
Abstract
PURPOSE We propose a new method, displacement spectrum (DiSpect) imaging, for probing in vivo complex tissue dynamics such as motion, flow, diffusion, and perfusion. Based on stimulated echoes and image phase, our flexible approach enables observations of the spin dynamics over short (milliseconds) to long (seconds) evolution times. METHODS The DiSpect method is a Fourier-encoded variant of displacement encoding with stimulated echoes, which encodes bulk displacement of spins that occurs between tagging and imaging in the image phase. However, this method fails to capture partial volume effects as well as blood flow. The DiSpect variant mitigates this by performing multiple scans with increasing displacement-encoding steps. Fourier analysis can then resolve the multidimensional spectrum of displacements that spins exhibit over the mixing time. In addition, repeated imaging following tagging can capture dynamic displacement spectra with increasing mixing times. RESULTS We demonstrate properties of DiSpect MRI using flow phantom experiments as well as in vivo brain scans. Specifically, the ability of DiSpect to perform retrospective vessel-selective perfusion imaging at multiple mixing times is highlighted. CONCLUSION The DiSpect variant is a new tool in the arsenal of MRI techniques for probing complex tissue dynamics. The flexibility and the rich information it provides open the possibility of alternative ways to quantitatively measure numerous complex spin dynamics, such as flow and perfusion within a single exam.
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Affiliation(s)
- Zhiyong Zhang
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China.,Department of Electrical Engineering and Computer Sciences, University of California Berkeley, Berkeley, California, USA
| | - Ekin Karasan
- Department of Electrical Engineering and Computer Sciences, University of California Berkeley, Berkeley, California, USA
| | - Karthik Gopalan
- Department of Electrical Engineering and Computer Sciences, University of California Berkeley, Berkeley, California, USA
| | - Chunlei Liu
- Department of Electrical Engineering and Computer Sciences, University of California Berkeley, Berkeley, California, USA.,Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, California, USA
| | - Michael Lustig
- Department of Electrical Engineering and Computer Sciences, University of California Berkeley, Berkeley, California, USA
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15
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Abstract
MRI is an essential diagnostic tool in the anatomic and functional evaluation of cardiovascular disease. In many practices, 2D phase-contrast (2D-PC) has been used for blood flow quantification. 4D Flow MRI is a time-resolved volumetric acquisition that captures the vector field of blood flow along with anatomic images. 4D Flow MRI provides a simpler acquisition compared to 2D-PC and facilitates a more accurate and comprehensive hemodynamic assessment. Advancements in accelerated imaging have significantly shortened scan times of 4D Flow MRI while preserving image quality, enabling this technology to transition from the research arena to routine clinical practice. In this article, we review technical optimization based on our clinical experience of over 10 years with 4D Flow MRI. We also present pearls and pitfalls in the practical application of 4D Flow MRI, including how to quantify cardiovascular shunts, valvular or vascular stenosis, and valvular regurgitation. As experience increases, and as 4D Flow sequences and post-processing software become more broadly available, 4D Flow MRI will likely become an essential component of cardiac imaging for practices involved in the management of congenital and acquired structural heart disease.
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16
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van Ooij P, Farag ES, Blanken CPS, Nederveen AJ, Groenink M, Planken RN, Boekholdt SM. Fully quantitative mapping of abnormal aortic velocity and wall shear stress direction in patients with bicuspid aortic valves and repaired coarctation using 4D flow cardiovascular magnetic resonance. J Cardiovasc Magn Reson 2021; 23:9. [PMID: 33588887 PMCID: PMC7885343 DOI: 10.1186/s12968-020-00703-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 12/20/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Helices and vortices in thoracic aortic blood flow measured with 4D flow cardiovascular magnetic resonance (CMR) have been associated with aortic dilation and aneurysms. Current approaches are semi-quantitative or when fully quantitative based on 2D plane placement. In this study, we present a fully quantitative and three-dimensional approach to map and quantify abnormal velocity and wall shear stress (WSS) at peak systole in patients with a bicuspid aortic valve (BAV) of which 52% had a repaired coarctation. METHODS 4D flow CMR was performed in 48 patients with BAV and in 25 healthy subjects at a spatiotemporal resolution of 2.5 × 2.5 × 2.5mm3/ ~ 42 ms and TE/TR/FA of 2.1 ms/3.4 ms/8° with k-t Principal Component Analysis factor R = 8. A 3D average of velocity and WSS direction was created for the normal subjects. Comparing BAV patient data with the 3D average map and selecting voxels deviating between 60° and 120° and > 120° yielded 3D maps and volume (in cm3) and surface (in cm2) quantification of abnormally directed velocity and WSS, respectively. Linear regression with Bonferroni corrected significance of P < 0.0125 was used to compare abnormally directed velocity volume and WSS surface in the ascending aorta with qualitative helicity and vorticity scores, with local normalized helicity (LNH) and quantitative vorticity and with patient characteristics. RESULTS The velocity volumes > 120° correlated moderately with the vorticity scores (R ~ 0.50, P < 0.001 for both observers). For WSS surface these results were similar. The velocity volumes between 60° and 120° correlated moderately with LNH (R = 0.66) but the velocity volumes > 120° did not correlate with quantitative vorticity. For abnormal velocity and WSS deviating between 60° and 120°, moderate correlations were found with aortic diameters (R = 0.50-0.70). For abnormal velocity and WSS deviating > 120°, additional moderate correlations were found with age and with peak velocity (stenosis severity) and a weak correlation with gender. Ensemble maps showed that more than 60% of the patients had abnormally directed velocity and WSS. Additionally, abnormally directed velocity and WSS was higher in the proximal descending aorta in the patients with repaired coarctation than in the patients where coarctation was never present. CONCLUSION The possibility to reveal directional abnormalities of velocity and WSS in 3D provides a new tool for hemodynamic characterization in BAV disease.
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Affiliation(s)
- Pim van Ooij
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Center, location AMC, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Emile S. Farag
- Department of Cardiothoracic Surgery, Amsterdam University Medical Center, location AMC, Amsterdam, The Netherlands
| | - Carmen P. S. Blanken
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Center, location AMC, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Aart J. Nederveen
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Center, location AMC, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Maarten Groenink
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Center, location AMC, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
- Department of Cardiology, Amsterdam University Medical Center, location AMC, Amsterdam, The Netherlands
| | - R. Nils Planken
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Center, location AMC, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - S. Matthijs Boekholdt
- Department of Cardiology, Amsterdam University Medical Center, location AMC, Amsterdam, The Netherlands
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17
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Wymer DT, Patel KP, Burke WF, Bhatia VK. Phase-Contrast MRI: Physics, Techniques, and Clinical Applications. Radiographics 2021; 40:122-140. [PMID: 31917664 DOI: 10.1148/rg.2020190039] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
With phase-contrast imaging, the MRI signal is used to visualize and quantify velocity. This imaging modality relies on phase data, which are intrinsic to all MRI signals. With use of bipolar gradients, degrees of phase shift are encoded and in turn correlated directly with the velocity of protons. The acquisition of diagnostic-quality images requires selection of the correct imaging plane to ensure accurate measurement and selection of the encoding velocity and thus prevent aliasing and achieve the highest signal-to-noise ratio. Multiple applications of phase-contrast imaging are actively used in clinical practice. One of the most common clinical uses is in cardiac valvular flow imaging, at which the data are used to assess the severity of valvular disease and quantify the shunt fraction. In neurologic imaging, phase-contrast imaging can be used to measure the flow of cerebrospinal fluid. This measurement can aid in the diagnosis and direct management of normal pressure hydrocephalus or be used to evaluate the severity of stenosis, such as that in Chiari I malformations. At vascular analysis, phase-contrast imaging can be used to visualize arterial and venous flow, and this application is used most commonly in the brain. Three-dimensional imaging can yield highly detailed flow data in a technique referred to as four-dimensional flow. A more recently identified application is in MR elastography. Shear waves created by using an impulse device can be velocity encoded, and this velocity is directly proportional to the stiffness of the organ, or the shear modulus. This imaging modality is most commonly used in the liver for evaluation of cirrhosis and steatosis, although research on the assessment of other organs is being performed. Phase-contrast imaging is an important tool in the arsenal of MRI examinations and has many applications. Proper use of phase-contrast imaging requires an understanding of the many practical and technical factors and unique physics principles underlying the technique.©RSNA, 2020.
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Affiliation(s)
- David T Wymer
- From the Department of Diagnostic Radiology, Mount Sinai Medical Center, 4300 Alton Rd, Miami Beach, FL 33140
| | - Kunal P Patel
- From the Department of Diagnostic Radiology, Mount Sinai Medical Center, 4300 Alton Rd, Miami Beach, FL 33140
| | - William F Burke
- From the Department of Diagnostic Radiology, Mount Sinai Medical Center, 4300 Alton Rd, Miami Beach, FL 33140
| | - Vinay K Bhatia
- From the Department of Diagnostic Radiology, Mount Sinai Medical Center, 4300 Alton Rd, Miami Beach, FL 33140
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18
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Srinivas S, Retson T, Simon A, Hattangadi-Gluth J, Hsiao A, Farid N. Quantification of hemodynamics of cerebral arteriovenous malformations after stereotactic radiosurgery using 4D flow magnetic resonance imaging. J Magn Reson Imaging 2020; 53:1841-1850. [PMID: 33354852 DOI: 10.1002/jmri.27490] [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: 10/16/2020] [Revised: 12/10/2020] [Accepted: 12/11/2020] [Indexed: 12/26/2022] Open
Abstract
Stereotactic radiosurgery (SRS) is used to treat cerebral arteriovenous malformations (AVMs). However, early evaluation of efficacy is difficult as structural magnetic resonance imaging (MRI)/magnetic resonance angiography (MRA) often does not demonstrate appreciable changes within the first 6 months. The aim of this study was to evaluate the use of four-dimensional (4D) flow MRI to quantify hemodynamic changes after SRS as early as 2 months. This was a retrospective observational study, which included 14 patients with both pre-SRS and post-SRS imaging obtained at multiple time points from 1 to 27 months after SRS. A 3T MRI Scanner was used to obtain T2 single-shot fast spin echo, time-of-flight MRA, and postcontrast 4D flow with three-dimensional velocity encoding between 150 and 200 cm/s. Post-hoc two-dimensional cross-sectional flow was measured for the dominant feeding artery, the draining vein, and the corresponding contralateral artery as a control. Measurements were performed by two independent observers, and reproducibility was assessed. Wilcoxon signed-rank tests were used to compare differences in flow, circumference, and pulsatility between the feeding artery and the contralateral artery both before and after SRS; and differences in nidus size and flow and circumference of the feeding artery and draining vein before and after SRS. Arterial flow (L/min) decreased in the primary feeding artery (mean: 0.1 ± 0.07 vs. 0.3 ± 0.2; p < 0.05) and normalized in comparison to the contralateral artery (mean: 0.1 ± 0.07 vs. 0.1 ± 0.07; p = 0.068). Flow decreased in the draining vein (mean: 0.1 ± 0.2 vs. 0.2 ± 0.2; p < 0.05), and the circumference of the draining vein also decreased (mean: 16.1 ± 8.3 vs. 15.7 ± 6.7; p < 0.05). AVM volume decreased after SRS (mean: 45.3 ± 84.8 vs. 38.1 ± 78.7; p < 0.05). However, circumference (mm) of the primary feeding artery remained similar after SRS (mean: 15.7 ± 2.7 vs. 16.1 ± 3.1; p = 0.600). 4D flow may be able to demonstrate early hemodynamic changes in AVMs treated with radiosurgery, and these changes appear to be more pronounced and occur earlier than the structural changes on standard MRI/MRA. Level of Evidence: 4 Technical Efficacy Stage: 1.
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Affiliation(s)
- Shanmukha Srinivas
- Department of Radiology, University of California-San Diego, San Diego, California, USA
| | - Tara Retson
- Department of Radiology, University of California-San Diego, San Diego, California, USA
| | - Aaron Simon
- Department of Radiation Medicine and Applied Sciences, University of California-San Diego, San Diego, California, USA
| | - Jona Hattangadi-Gluth
- Department of Radiation Medicine and Applied Sciences, University of California-San Diego, San Diego, California, USA
| | - Albert Hsiao
- Department of Radiology, University of California-San Diego, San Diego, California, USA
| | - Nikdokht Farid
- Department of Radiology, University of California-San Diego, San Diego, California, USA
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19
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Roberts TA, van Amerom JFP, Uus A, Lloyd DFA, van Poppel MPM, Price AN, Tournier JD, Mohanadass CA, Jackson LH, Malik SJ, Pushparajah K, Rutherford MA, Razavi R, Deprez M, Hajnal JV. Fetal whole heart blood flow imaging using 4D cine MRI. Nat Commun 2020; 11:4992. [PMID: 33020487 PMCID: PMC7536221 DOI: 10.1038/s41467-020-18790-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 09/10/2020] [Indexed: 12/26/2022] Open
Abstract
Prenatal detection of congenital heart disease facilitates the opportunity for potentially life-saving care immediately after the baby is born. Echocardiography is routinely used for screening of morphological malformations, but functional measurements of blood flow are scarcely used in fetal echocardiography due to technical assumptions and issues of reliability. Magnetic resonance imaging (MRI) is readily used for quantification of abnormal blood flow in adult hearts, however, existing in utero approaches are compromised by spontaneous fetal motion. Here, we present and validate a novel method of MRI velocity-encoding combined with a motion-robust reconstruction framework for four-dimensional visualization and quantification of blood flow in the human fetal heart and major vessels. We demonstrate simultaneous 4D visualization of the anatomy and circulation, which we use to quantify flow rates through various major vessels. The framework introduced here could enable new clinical opportunities for assessment of the fetal cardiovascular system in both health and disease.
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Affiliation(s)
- Thomas A Roberts
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, SE1 7EH, UK.
| | - Joshua F P van Amerom
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, SE1 7EH, UK
| | - Alena Uus
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, SE1 7EH, UK
| | - David F A Lloyd
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, SE1 7EH, UK
- Department of Congenital Heart Disease, Evelina Children's Hospital, London, SE1 7EH, UK
| | - Milou P M van Poppel
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, SE1 7EH, UK
- Department of Congenital Heart Disease, Evelina Children's Hospital, London, SE1 7EH, UK
| | - Anthony N Price
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, SE1 7EH, UK
| | - Jacques-Donald Tournier
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, SE1 7EH, UK
| | - Chloe A Mohanadass
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, SE1 7EH, UK
| | - Laurence H Jackson
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, SE1 7EH, UK
| | - Shaihan J Malik
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, SE1 7EH, UK
| | - Kuberan Pushparajah
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, SE1 7EH, UK
- Department of Congenital Heart Disease, Evelina Children's Hospital, London, SE1 7EH, UK
| | - Mary A Rutherford
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, SE1 7EH, UK
- Centre for the Developing Brain, King's College London, London, SE1 7EH, UK
| | - Reza Razavi
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, SE1 7EH, UK
- Department of Congenital Heart Disease, Evelina Children's Hospital, London, SE1 7EH, UK
| | - Maria Deprez
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, SE1 7EH, UK
| | - Joseph V Hajnal
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, SE1 7EH, UK
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20
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Perez-Raya I, Fathi MF, Baghaie A, Sacho RH, Koch KM, D'Souza RM. Towards multi-modal data fusion for super-resolution and denoising of 4D-Flow MRI. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2020; 36:e3381. [PMID: 32627366 DOI: 10.1002/cnm.3381] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 05/26/2020] [Accepted: 05/27/2020] [Indexed: 06/11/2023]
Abstract
4D-Flow magnetic resonance imaging (MRI) has enabled in vivo time-resolved measurement of three-dimensional blood flow velocities in the human vascular system. However, its clinical use has been hampered by two main issues, namely, low spatio-temporal resolution and acquisition noise. While patient-specific computational fluid dynamics (CFD) simulations can address the resolution and noise issues, its fidelity is impacted by accuracy of estimation of boundary conditions, model parameters, vascular geometry, and flow model assumptions. In this paper a scheme to address limitations of both modalities through data-fusion is presented. The solutions of the patient-specific CFD simulation are characterized using proper orthogonal decomposition (POD). Next, a process of projecting the 4D-Flow MRI data onto the POD basis and projection coefficient mapping using generalized dynamic mode decomposition (DMD) enables simultaneous super-resolution and denoising of 4D-Flow MRI. The method has been tested using numerical phantoms derived from patient-specific aneurysmal geometries and applied to in vivo 4D-Flow MRI data.
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Affiliation(s)
- Isaac Perez-Raya
- Department of Mechanical Engineering, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Mojtaba F Fathi
- Department of Mechanical Engineering, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Ahmadreza Baghaie
- Department of Electrical and Computer Engineering, New York Institute of Technology, Long Island, New York, USA
| | - Raphael H Sacho
- Department of Neurosurgery, Medical College of Wisconsin, Wauwatosa, Wisconsin, USA
| | - Kevin M Koch
- Department of Radiology, Medical College of Wisconsin, Wauwatosa, Wisconsin, USA
| | - Roshan M D'Souza
- Department of Mechanical Engineering, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
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21
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Validation of four-dimensional flow cardiovascular magnetic resonance for aortic stenosis assessment. Sci Rep 2020; 10:10569. [PMID: 32601326 PMCID: PMC7324609 DOI: 10.1038/s41598-020-66659-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 05/18/2020] [Indexed: 11/18/2022] Open
Abstract
The management of patients with aortic stenosis (AS) crucially depends on accurate diagnosis. The main aim of this study were to validate the four-dimensional flow (4D flow) cardiovascular magnetic resonance (CMR) methods for AS assessment. Eighteen patients with clinically severe AS were recruited. All patients had pre-valve intervention 6MWT, echocardiography and CMR with 4D flow. Of these, ten patients had a surgical valve replacement, and eight patients had successful transcatheter aortic valve implantation (TAVI). TAVI patients had invasive pressure gradient assessments. A repeat assessment was performed at 3–4 months to assess the remodelling response. The peak pressure gradient by 4D flow was comparable to an invasive pressure gradient (54 ± 26 mmHG vs 50 ± 34 mmHg, P = 0.67). However, Doppler yielded significantly higher pressure gradient compared to invasive assessment (61 ± 32 mmHG vs 50 ± 34 mmHg, P = 0.0002). 6MWT was associated with 4D flow CMR derived pressure gradient (r = −0.45, P = 0.01) and EOA (r = 0.54, P < 0.01) but only with Doppler EOA (r = 0.45, P = 0.01). Left ventricular mass regression was better associated with 4D flow derived pressure gradient change (r = 0.64, P = 0.04). 4D flow CMR offers an alternative method for non-invasive assessment of AS. In addition, 4D flow derived valve metrics have a superior association to prognostically relevant 6MWT and LV mass regression than echocardiography.
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22
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Vali A, Schmitter S, Ma L, Flassbeck S, Schmidt S, Markl M, Schnell S. Development of a rotation phantom for phase contrast MRI sequence validation and quality control. Magn Reson Med 2020; 84:3333-3341. [DOI: 10.1002/mrm.28343] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Revised: 05/11/2020] [Accepted: 05/12/2020] [Indexed: 12/15/2022]
Affiliation(s)
- Alireza Vali
- Department of Radiology Northwestern University Chicago Illinois USA
| | - Sebastian Schmitter
- Physikalisch Technische Bundesanstalt Braunschweig and Berlin Germany
- Medical Physics in Radiology German Cancer Research Center (DKFZ) Heidelberg Germany
| | - Liliana Ma
- Department of Radiology Northwestern University Chicago Illinois USA
- Department of Biomedical Engineering Northwestern University Evanston Illinois USA
| | - Sebastian Flassbeck
- Medical Physics in Radiology German Cancer Research Center (DKFZ) Heidelberg Germany
| | - Simon Schmidt
- Medical Physics in Radiology German Cancer Research Center (DKFZ) Heidelberg Germany
- Faculty of Physics and Astronomy Heidelberg University Heidelberg Germany
| | - Michael Markl
- Department of Radiology Northwestern University Chicago Illinois USA
- Department of Biomedical Engineering Northwestern University Evanston Illinois USA
| | - Susanne Schnell
- Department of Radiology Northwestern University Chicago Illinois USA
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23
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Berhane H, Scott M, Elbaz M, Jarvis K, McCarthy P, Carr J, Malaisrie C, Avery R, Barker AJ, Robinson JD, Rigsby CK, Markl M. Fully automated 3D aortic segmentation of 4D flow MRI for hemodynamic analysis using deep learning. Magn Reson Med 2020; 84:2204-2218. [PMID: 32167203 DOI: 10.1002/mrm.28257] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 02/18/2020] [Accepted: 02/24/2020] [Indexed: 12/18/2022]
Abstract
PURPOSE To generate fully automated and fast 4D-flow MRI-based 3D segmentations of the aorta using deep learning for reproducible quantification of aortic flow, peak velocity, and dimensions. METHODS A total of 1018 subjects with aortic 4D-flow MRI (528 with bicuspid aortic valve, 376 with tricuspid aortic valve and aortic dilation, 114 healthy controls) comprised the data set. A convolutional neural network was trained to generate 3D aortic segmentations from 4D-flow data. Manual segmentations served as the ground truth (N = 499 training, N = 101 validation, N = 418 testing). Dice scores, Hausdorff distance, and average symmetrical surface distance were calculated to assess performance. Aortic flow, peak velocity, and lumen dimensions were quantified at the ascending, arch, and descending aorta and compared using Bland-Altman analysis. Interobserver variability of manual analysis was assessed on a subset of 40. RESULTS Convolutional neural network segmentation required 0.438 ± 0.355 seconds versus 630 ± 254 seconds for manual analysis and demonstrated excellent performance with a median Dice score of 0.951 (0.930-0.966), Hausdorff distance of 2.80 (2.13-4.35), and average symmetrical surface distance of 0.176 (0.119-0.290). Excellent agreement was found for flow, peak velocity, and dimensions with low bias and limits of agreement less than 10% difference versus manual analysis. For aortic volume, limits of agreement were moderate within 16.3%. Interobserver variability (median Dice score: 0.950; Hausdorff distance: 2.45; and average symmetrical surface distance: 0.145) and convolutional neural network-based analysis (median Dice score: 0.953-0.959; Hausdorff distance: 2.24-2.91; and average symmetrical surface distance: 0.145-1.98 to observers) demonstrated similar reproducibility. CONCLUSIONS Deep learning enabled fast and automated 3D aortic segmentation from 4D-flow MRI, demonstrating its potential for efficient clinical workflows. Future studies should investigate its utility for other vasculature and multivendor applications.
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Affiliation(s)
- Haben Berhane
- Department of Medical Imaging, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois
| | - Michael Scott
- Department of Biomedical Engineering, Northwestern University, Chicago, Illinois.,Department of Radiology, Northwestern University, Chicago, Illinois
| | - Mohammed Elbaz
- Department of Biomedical Engineering, Northwestern University, Chicago, Illinois.,Department of Radiology, Northwestern University, Chicago, Illinois
| | - Kelly Jarvis
- Department of Radiology, Northwestern University, Chicago, Illinois
| | - Patrick McCarthy
- Divison of Cardiac Surgery, Northwestern University, Chicago, Illinois
| | - James Carr
- Department of Biomedical Engineering, Northwestern University, Chicago, Illinois
| | - Chris Malaisrie
- Department of Radiology, Northwestern University, Chicago, Illinois
| | - Ryan Avery
- Department of Radiology, Northwestern University, Chicago, Illinois
| | - Alex J Barker
- Anschutz Medical Campus, University of Colorado, Aurora, Colorado
| | - Joshua D Robinson
- Department of Medical Imaging, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois
| | - Cynthia K Rigsby
- Department of Medical Imaging, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois
| | - Michael Markl
- Department of Biomedical Engineering, Northwestern University, Chicago, Illinois.,Department of Radiology, Northwestern University, Chicago, Illinois
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Callaghan FM, Burkhardt B, Geiger J, Valsangiacomo Buechel ER, Kellenberger CJ. Flow quantification dependency on background phase correction techniques in 4D‐flow MRI. Magn Reson Med 2019; 83:2264-2275. [DOI: 10.1002/mrm.28085] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 10/09/2019] [Accepted: 10/24/2019] [Indexed: 12/23/2022]
Affiliation(s)
- Fraser M. Callaghan
- Center for MR Research University Children's Hospital Zurich Switzerland
- Children's Research Center University Children's Hospital Zurich Switzerland
| | - Barbara Burkhardt
- Children's Research Center University Children's Hospital Zurich Switzerland
- Division of Pediatric Cardiology University Children's Hospital Zurich Switzerland
| | - Julia Geiger
- Children's Research Center University Children's Hospital Zurich Switzerland
- Department of Diagnostic Imaging University Children's Hospital Zurich Switzerland
| | - Emanuela R. Valsangiacomo Buechel
- Children's Research Center University Children's Hospital Zurich Switzerland
- Division of Pediatric Cardiology University Children's Hospital Zurich Switzerland
| | - Christian J. Kellenberger
- Children's Research Center University Children's Hospital Zurich Switzerland
- Department of Diagnostic Imaging University Children's Hospital Zurich Switzerland
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25
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Automatic correction of background phase offset in 4D-flow of great vessels and of the heart in MRI using a third-order surface model. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2019; 32:629-642. [DOI: 10.1007/s10334-019-00765-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 06/03/2019] [Accepted: 06/13/2019] [Indexed: 10/26/2022]
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26
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Aristova M, Vali A, Ansari SA, Shaibani A, Alden TD, Hurley MC, Jahromi BS, Potts MB, Markl M, Schnell S. Standardized Evaluation of Cerebral Arteriovenous Malformations Using Flow Distribution Network Graphs and Dual-venc 4D Flow MRI. J Magn Reson Imaging 2019; 50:1718-1730. [PMID: 31070849 DOI: 10.1002/jmri.26784] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 04/29/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cerebral arteriovenous malformations (AVMs) are pathological connections between arteries and veins. Dual-venc 4D flow MRI, an extended 4D flow MRI method with improved velocity dynamic range, provides time-resolved 3D cerebral hemodynamics. PURPOSE To optimize dual-venc 4D flow imaging parameters for AVM; to assess the relationship between spatial resolution, acceleration, and flow quantification accuracy; and to introduce and apply the flow distribution network graph (FDNG) paradigm for storing and analyzing complex neurovascular 4D flow data. STUDY TYPE Retrospective cohort study. SUBJECTS/PHANTOM Scans were performed in a specialized flow phantom: 26 healthy subjects (age 41 ± 17 years) and five AVM patients (age 27-68 years). FIELD STRENGTH/SEQUENCE Dual-venc 4D flow with varying spatial resolution and acceleration factors were performed at 3T field strength. ASSESSMENT Quantification accuracy was assessed in vitro by direct comparison to measured flow. FDNGs were used to quantify and compare flow, peak velocity (PV), and pulsatility index (PI) between healthy controls with various Circle of Willis (CoW) anatomy and AVM patients. STATISTICAL TESTS In vitro measurements were compared to ground truth with Student's t-test. In vivo groups were compared with Wilcoxon rank-sum test and Kruskal-Wallis test. RESULTS Flow was overestimated in all in vitro experiments, by an average 7.1 ± 1.4% for all measurement conditions. Error in flow measurement was significantly correlated with number of voxels across the channel (P = 3.11 × 10-28 ) but not with acceleration factor (P = 0.74). For the venous-arterial PV and PI ratios, a significant difference was found between AVM nidal and extranidal circulation (P = 0.008 and 0.05, respectively), and between AVM nidal and healthy control circulation (P = 0.005 and 0.003, respectively). DATA CONCLUSION Dual-venc 4D flow MRI and standardized FDNG analysis might be feasible in clinical applications. Venous-arterial ratios of PV and PI are proposed as network-based biomarkers characterizing AVM nidal hemodynamics. LEVEL OF EVIDENCE 3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;50:1718-1730.
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Affiliation(s)
- Maria Aristova
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.,McCormick School of Engineering, Biomedical Engineering, Northwestern University, Evanston, USA
| | - Alireza Vali
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Sameer A Ansari
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.,Department of Neurosurgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.,Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Ali Shaibani
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.,Department of Neurosurgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Tord D Alden
- Department of Neurosurgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.,Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA
| | - Michael C Hurley
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.,Department of Neurosurgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Babak S Jahromi
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.,Department of Neurosurgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Matthew B Potts
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.,Department of Neurosurgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Michael Markl
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.,McCormick School of Engineering, Biomedical Engineering, Northwestern University, Evanston, USA
| | - Susanne Schnell
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
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27
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Puiseux T, Sewonu A, Meyrignac O, Rousseau H, Nicoud F, Mendez S, Moreno R. Reconciling PC-MRI and CFD: An in-vitro study. NMR IN BIOMEDICINE 2019; 32:e4063. [PMID: 30747461 DOI: 10.1002/nbm.4063] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 11/16/2018] [Accepted: 12/18/2018] [Indexed: 05/25/2023]
Abstract
Several well-resolved 4D Flow MRI acquisitions of an idealized rigid flow phantom featuring an aneurysm, a curved channel as well as a bifurcation were performed under pulsatile regime. The resulting hemodynamics were processed to remove MRI artifacts. Subsequently, they were compared with CFD predictions computed on the same flow domain, using an in-house high-order low dissipative flow solver. Results show that reaching a good agreement is not straightforward but requires proper treatments of both techniques. Several sources of discrepancies are highlighted and their impact on the final correlation evaluated. While a very poor correlation (r2 = 0.63) is found in the entire domain between raw MRI and CFD data, correlation as high as r2 = 0.97 is found when artifacts are removed by post-processing the MR data and down sampling the CFD results to match the MRI spatial and temporal resolutions. This work demonstrates that, in a well-controlled environment, both PC-MRI and CFD might bring reliable and correlated flow quantities when a proper methodology to reduce the errors is followed.
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Affiliation(s)
- Thomas Puiseux
- IMAG, Univ Montpellier, CNRS, Montpellier, France
- ALARA Expertise, Strasbourg, France
| | - Anou Sewonu
- ALARA Expertise, Strasbourg, France
- I2MC, INSERM U1048, Toulouse, France
| | - Olivier Meyrignac
- I2MC, INSERM U1048, Toulouse, France
- Department of Radiology, CHU de Toulouse, Toulouse, France
| | - Hervé Rousseau
- I2MC, INSERM U1048, Toulouse, France
- Department of Radiology, CHU de Toulouse, Toulouse, France
| | | | - Simon Mendez
- IMAG, Univ Montpellier, CNRS, Montpellier, France
| | - Ramiro Moreno
- ALARA Expertise, Strasbourg, France
- I2MC, INSERM U1048, Toulouse, France
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Sakhare AR, Barisano G, Pa J. Assessing test-retest reliability of phase contrast MRI for measuring cerebrospinal fluid and cerebral blood flow dynamics. Magn Reson Med 2019; 82:658-670. [PMID: 31020721 DOI: 10.1002/mrm.27752] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 03/05/2019] [Accepted: 03/06/2019] [Indexed: 02/06/2023]
Abstract
PURPOSE Pathological states occur when cerebrospinal fluid (CSF) and cerebral blood flow (CBF) dynamics become dysregulated in the brain. Phase-contrast MRI (PC-MRI) is a noninvasive imaging technique that enables quantitative measurements of CSF and CBF flow. While studies have validated PC-MRI as an imaging technique for flow, few studies have evaluated its reliability for CSF and CBF flow parameters commonly associated with neurological disease. The purpose of this study was to evaluate test-retest reliability at the cerebral aqueduct (CA) and C2-C3 area using PC-MRI to assess the feasibility of investigating CSF and CBF flow dynamics. METHODS This study was performed on 27 cognitively normal young adults (ages 20-35 years). Flow data was acquired on a 3T Siemens Prisma using a 2D cine-PC pulse sequence. Three consecutive flow measurements were acquired at the CA and C2-C3 area. Intraclass correlation coefficient (ICC) and coefficient of variance (CV) were used to evaluate intrarater, inter-rater, and test-retest reliability. RESULTS Among the 26 flow parameters analyzed, 22 had excellent reliability (ICC > 0.80), including measurements of CSF stroke volume, flush peak, and fill peak, and 4 parameters had good reliability (ICC 0.60-0.79). 16 flow parameters had a mean CV ≤ 10%, 7 had a CV ≤ 15%, and 3 had a CV ≤ 30%. All CSF and CBF flow measurements had excellent inter-rater and intrarater reliability (ICC > 0.80). CONCLUSION This study shows that CSF and CBF flow can be reliably measured at the CA and C2-C3 area using PC-MRI, making it a promising tool for studying flow dynamics in the central nervous system.
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Affiliation(s)
- Ashwin R Sakhare
- Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, California.,Department of Neurology, Laboratory of Neuro Imaging, Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, California
| | - Giuseppe Barisano
- Department of Neurology, Laboratory of Neuro Imaging, Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, California.,Neuroscience Graduate Program, University of Southern California, Los Angeles, California
| | - Judy Pa
- Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, California.,Department of Neurology, Laboratory of Neuro Imaging, Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, California.,Neuroscience Graduate Program, University of Southern California, Los Angeles, California
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29
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Lindstrøm EK, Ringstad G, Mardal KA, Eide PK. Cerebrospinal fluid volumetric net flow rate and direction in idiopathic normal pressure hydrocephalus. NEUROIMAGE-CLINICAL 2018; 20:731-741. [PMID: 30238917 PMCID: PMC6154456 DOI: 10.1016/j.nicl.2018.09.006] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 09/06/2018] [Accepted: 09/11/2018] [Indexed: 12/11/2022]
Abstract
The aim of the present study was to examine cerebrospinal fluid (CSF) volumetric net flow rate and direction at the cranio-cervical junction (CCJ) and cerebral aqueduct in individuals with idiopathic normal pressure hydrocephalus (iNPH) using cardiac-gated phase-contrast magnetic resonance imaging (PC-MRI). An in-depth, pixel-by-pixel analysis of regions of interest from the CCJ and cerebral aqueduct, respectively, was done in 26 iNPH individuals, and in 4 healthy subjects for validation purposes. Results from patients were compared with over-night measurements of static and pulsatile intracranial pressure (ICP). In iNPH, CSF net flow at CCJ was cranially directed in 17/22 as well as in 4/4 healthy subjects. Estimated daily CSF volumetric net flow rate at CCJ was 6.9 ± 9.9 L/24 h in iNPH patients and 4.5 ± 5.0 L/24 h in healthy individuals. Within the cerebral aqueduct, the CSF net flow was antegrade in 7/21 iNPH patients and in 4/4 healthy subjects, while it was retrograde (i.e. towards ventricles) in 14/21 iNPH patients. Estimated daily CSF volumetric net flow rate in cerebral aqueduct was 1.1 ± 2.2 L/24 h in iNPH while 295 ± 53 mL/24 h in healthy individuals. Magnitude of cranially directed CSF net flow in cerebral aqueduct was highest in iNPH individuals with signs of impaired intracranial compliance. The study results indicate CSF flow volumes and direction that are profoundly different from previously assumed. We hypothesize that spinal CSF formation may serve to buffer increased demand for CSF flow through the glymphatic system during sleep and during deep inspiration to compensate for venous outflow.
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Affiliation(s)
- Erika Kristina Lindstrøm
- Department of Mathematics, Faculty of Mathematics and Natural Sciences, University of Oslo, Norway
| | - Geir Ringstad
- Division of Radiology and Nuclear Medicine, Department of Radiology, Oslo University Hospital - Rikshospitalet, Oslo, Norway; Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Kent-Andre Mardal
- Department of Mathematics, Faculty of Mathematics and Natural Sciences, University of Oslo, Norway; Department of Numerical Analysis and Scientific Computing, Simula Research Laboratory, Oslo, Norway
| | - Per Kristian Eide
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway; Department of Neurosurgery, Oslo University Hospital, Rikshospitalet, Oslo, Norway.
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30
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Kim M, Collier GJ, Wild JM, Chung YM. Effect of upper airway on tracheobronchial fluid dynamics. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e3112. [PMID: 29856119 DOI: 10.1002/cnm.3112] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 05/24/2018] [Accepted: 05/27/2018] [Indexed: 05/17/2023]
Abstract
The upper airways play a significant role in the tracheal flow dynamics. Despite many previous studies, however, the effect of the upper airways on the ventilation distribution in distal airways has remained a challenge. The aim of this study is to experimentally and computationally investigate the dynamic behaviour in the intratracheal flow induced by the upper respiratory tract and to assess its influence on the subsequent tributaries. Patient-specific images from 2 different modalities (magnetic resonance imaging of the upper airways and computed tomography of the lower airways) were segmented and combined. An experimental phantom of patient-specific airways (including the oral cavity, larynx, trachea, down to generations 6-8) was generated using 3D printing. The flow velocities in this phantom model were measured by the flow-sensitised phase contrast magnetic resonance imaging technique and compared with the computational fluid dynamics simulations. Both experimental and computational results show a good agreement in the time-averaged velocity fields as well as fluctuating velocity. The flows in the proximal trachea were complex and unsteady under both lower- and higher-flow rate conditions. Computational fluid dynamics simulations were also performed with an airways model without the upper airways. Although the flow near the carina remained unstable only when the inflow rate was high, the influence of the upper airways caused notable changes in distal flow distributions when the 2 airways models were compared with and without the upper airways. The results suggest that the influence of the upper airways should be included in the respiratory flow assessment as the upper airways extensively affect the flows in distal airways and consequent ventilation distribution in the lungs.
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Affiliation(s)
- Minsuok Kim
- School of Engineering, University of Warwick, Coventry, UK
| | - Guilhem J Collier
- Academic Unit of Radiology, Institute for In Silico Medicine, University of Sheffield, Sheffield, UK
| | - Jim M Wild
- Academic Unit of Radiology, Institute for In Silico Medicine, University of Sheffield, Sheffield, UK
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31
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Ringstad G, Lindstrøm EK, Vatnehol SAS, Mardal KA, Emblem KE, Eide PK. Non-invasive assessment of pulsatile intracranial pressure with phase-contrast magnetic resonance imaging. PLoS One 2017; 12:e0188896. [PMID: 29190788 PMCID: PMC5708728 DOI: 10.1371/journal.pone.0188896] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 11/02/2017] [Indexed: 12/04/2022] Open
Abstract
Invasive monitoring of pulsatile intracranial pressure can accurately predict shunt response in patients with idiopathic normal pressure hydrocephalus, but may potentially cause complications such as bleeding and infection. We tested how a proposed surrogate parameter for pulsatile intracranial pressure, the phase-contrast magnetic resonance imaging derived pulse pressure gradient, compared with its invasive counterpart. In 22 patients with suspected idiopathic normal pressure hydrocephalus, preceding invasive intracranial pressure monitoring, and any surgical shunt procedure, we calculated the pulse pressure gradient from phase-contrast magnetic resonance imaging derived cerebrospinal fluid flow velocities obtained at the upper cervical spinal canal using a simplified Navier-Stokes equation. Repeated measurements of the pulse pressure gradient were also undertaken in four healthy controls. Of 17 shunted patients, 16 responded, indicating high proportion of “true” normal pressure hydrocephalus in the patient cohort. However, there was no correlation between the magnetic resonance imaging derived pulse pressure gradient and pulsatile intracranial pressure (R = -.18, P = .43). Pulse pressure gradients were also similar in patients and healthy controls (P = .26), and did not differ between individuals with pulsatile intracranial pressure above or below established thresholds for shunt treatment (P = .97). Assessment of pulse pressure gradient at level C2 was therefore not found feasible to replace invasive monitoring of pulsatile intracranial pressure in selection of patients with idiopathic normal pressure hydrocephalus for surgical shunting. Unlike invasive, overnight monitoring, the pulse pressure gradient from magnetic resonance imaging comprises short-term pressure fluctuations only. Moreover, complexity of cervical cerebrospinal fluid flow and -pulsatility at the upper cervical spinal canal may render the pulse pressure gradient a poor surrogate marker for intracranial pressure pulsations.
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Affiliation(s)
- Geir Ringstad
- Department of Radiology and Nuclear Medicine, Oslo University Hospital—Rikshospitalet, Oslo, Norway
- Faculty of Medicine, University of Oslo, Oslo, Norway
- * E-mail:
| | - Erika Kristina Lindstrøm
- Department of Mathematics, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | - Svein Are Sirirud Vatnehol
- Faculty of Medicine, University of Oslo, Oslo, Norway
- The Intervention Centre, Oslo University Hospital, Oslo, Norway
| | - Kent-André Mardal
- Department of Mathematics, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway
| | | | - Per Kristian Eide
- Faculty of Medicine, University of Oslo, Oslo, Norway
- Department of Neurosurgery, Oslo University Hospital, Oslo, Norway
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32
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Deng Z, Fan Z, Lee SE, Nguyen C, Xie Y, Pang J, Bi X, Yang Q, Choi BW, Kim JS, Berman D, Chang HJ, Li D. Noninvasive measurement of pressure gradient across a coronary stenosis using phase contrast (PC)-MRI: A feasibility study. Magn Reson Med 2016; 77:529-537. [PMID: 28019028 DOI: 10.1002/mrm.26579] [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: 07/07/2016] [Revised: 10/24/2016] [Accepted: 11/21/2016] [Indexed: 01/10/2023]
Abstract
PURPOSE To investigate the feasibility of blood pressure difference measurement, ΔP, across the coronary artery using phase contrast (PC)-MRI for potential noninvasive assessment of the functional significance of coronary artery stenosis. METHODS Three-directional velocities in the coronary arteries acquired using 2D-PC-MRI were used with the Navier-Stokes equations to derive ΔP. Repeat phantom studies were performed to assess the reproducibility of flow velocity and ΔP. ΔP derived using PC-MRI (ΔPMR ) and that obtained using pressure transducer (ΔPPT ) were compared. Reproducibility of coronary flow velocity was assessed in healthy controls (n = 11). Patients with suspected coronary artery disease (n = 6) were studied to evaluate the feasibility of ΔPMR measurement across a coronary stenosis. RESULTS Phantom: Good overall reproducibility of flow velocity and ΔP measurements and excellent correlation (ΔPMR vs ΔPPT ) was observed: intraclass correlation (ICC) of 0.95(Vz ), 0.72(Vx ), 0.73(Vy ), and 0.87(ΔPMR ) and R2 = 0.94, respectively. Human: Good reproducibility of coronary flow velocity was observed: ICC of 0.94/0.95(Vz ), 0.76/0.74(Vx ), and 0.80/0.77(Vy ) at cardiac phase 1/2. Significant (p = 0.025) increase in ΔPMR was observed in patients (6.40 ± 4.43 mmHg) versus controls (0.70 ± 0.57 mmHg). CONCLUSION ΔPMR in the coronary arteries is feasible. Upon further validation using the invasive measure, ΔPMR has the potential for noninvasive assessment of coronary artery stenosis. Magn Reson Med 77:529-537, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Zixin Deng
- Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA.,Department of Bioengineering, University of California, Los Angeles, California, USA
| | - Zhaoyang Fan
- Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Sang-Eun Lee
- Division of Cardiology, Severance Cardiovascular Hospital, Seoul, South Korea
| | - Christopher Nguyen
- Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Yibin Xie
- Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Jianing Pang
- Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | | | - Qi Yang
- Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | | | - Jung-Sun Kim
- Division of Cardiology, Severance Cardiovascular Hospital, Seoul, South Korea
| | - Daniel Berman
- Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Hyuk-Jae Chang
- Division of Cardiology, Severance Cardiovascular Hospital, Seoul, South Korea
| | - Debiao Li
- Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA.,Department of Bioengineering, University of California, Los Angeles, California, USA.,Department of Medicine, University of California, Los Angeles, California, USA
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33
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Advanced flow MRI: emerging techniques and applications. Clin Radiol 2016; 71:779-95. [PMID: 26944696 DOI: 10.1016/j.crad.2016.01.011] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 12/10/2015] [Accepted: 01/10/2016] [Indexed: 12/12/2022]
Abstract
Magnetic resonance imaging (MRI) techniques provide non-invasive and non-ionising methods for the highly accurate anatomical depiction of the heart and vessels throughout the cardiac cycle. In addition, the intrinsic sensitivity of MRI to motion offers the unique ability to acquire spatially registered blood flow simultaneously with the morphological data, within a single measurement. In clinical routine, flow MRI is typically accomplished using methods that resolve two spatial dimensions in individual planes and encode the time-resolved velocity in one principal direction, typically oriented perpendicular to the two-dimensional (2D) section. This review describes recently developed advanced MRI flow techniques, which allow for more comprehensive evaluation of blood flow characteristics, such as real-time flow imaging, 2D multiple-venc phase contrast MRI, four-dimensional (4D) flow MRI, quantification of complex haemodynamic properties, and highly accelerated flow imaging. Emerging techniques and novel applications are explored. In addition, applications of these new techniques for the improved evaluation of cardiovascular (aorta, pulmonary arteries, congenital heart disease, atrial fibrillation, coronary arteries) as well as cerebrovascular disease (intra-cranial arteries and veins) are presented.
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34
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Speelman L, Teng Z, Nederveen AJ, van der Lugt A, Gillard JH. MRI-based biomechanical parameters for carotid artery plaque vulnerability assessment. Thromb Haemost 2016; 115:493-500. [PMID: 26791734 DOI: 10.1160/th15-09-0712] [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: 09/08/2015] [Accepted: 12/13/2015] [Indexed: 12/18/2022]
Abstract
Carotid atherosclerotic plaques are a major cause of ischaemic stroke. The biomechanical environment to which the arterial wall and plaque is subjected to plays an important role in the initiation, progression and rupture of carotid plaques. MRI is frequently used to characterize the morphology of a carotid plaque, but new developments in MRI enable more functional assessment of carotid plaques. In this review, MRI based biomechanical parameters are evaluated on their current status, clinical applicability, and future developments. Blood flow related biomechanical parameters, including endothelial wall shear stress and oscillatory shear index, have been shown to be related to plaque formation. Deriving these parameters directly from MRI flow measurements is feasible and has great potential for future carotid plaque development prediction. Blood pressure induced stresses in a plaque may exceed the tissue strength, potentially leading to plaque rupture. Multi-contrast MRI based stress calculations in combination with tissue strength assessment based on MRI inflammation imaging may provide a plaque stress-strength balance that can be used to assess the plaque rupture risk potential. Direct plaque strain analysis based on dynamic MRI is already able to identify local plaque displacement during the cardiac cycle. However, clinical evidence linking MRI strain to plaque vulnerability is still lacking. MRI based biomechanical parameters may lead to improved assessment of carotid plaque development and rupture risk. However, better MRI systems and faster sequences are required to improve the spatial and temporal resolution, as well as increase the image contrast and signal-to-noise ratio.
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Affiliation(s)
- Lambert Speelman
- Dr. Lambert Speelman, Department of Biomedical Engineering, Ee 23.38B, P.O Box 2040, 3000 CA Rotterdam, the Netherlands, Tel.: +31 10 70 44039, Fax: +31 10 70 44720, E-mail:
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Krishnamurthy LC, Mao D, King KS, Lu H. Correction and optimization of a T2-based approach to map blood oxygenation in small cerebral veins. Magn Reson Med 2015; 75:1100-9. [PMID: 25846113 DOI: 10.1002/mrm.25686] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 01/28/2015] [Accepted: 02/17/2015] [Indexed: 12/11/2022]
Abstract
PURPOSE Cerebral venous blood oxygenation (Yv ) is an important biomarker in brain physiology and function. The present study proposes a procedure to provide a quantitative map of the brain's intravascular Yv. THEORY AND METHODS The method is based on a pulse sequence, T2 -Relaxation-Under-Phase-Contrast (TRU-PC) MRI, with postprocessing approaches to correct eddy-current effects. A complete scan protocol consists of four TRU-PC scans sensitized to large and small vessels with anterior-posterior and foot-head flow-encoding directions, and the data are analyzed conjunctively. Eddy-current correction was performed by fitting the tissue phase to a hyperplane, and then subtracting the eddy-current phase from the measured vessel phase. The reproducibility of the Yv-maps was examined in five participants. Sensitivity of the Yv map to a caffeine challenge was studied in another five participants. RESULTS Removal of eddy-current induced artifact allowed for the correction of T2 measurements, as demonstrated in vivo and with simulation. A Yv-map depicting all vessels in the slice can be obtained with the proposed protocol. Test-retest variability of the Yv -map was 3.7 ± 1.2%. Yv reduction can be reliably detected (P < 0.001) following the caffeine ingestion. CONCLUSION With the proposed TRU-PC protocol and eddy-current correction procedure, an accurate, vessel-specific Yv map of the human brain can be obtained.
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Affiliation(s)
- Lisa C Krishnamurthy
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Department of Biomedical Engineering, University of Texas at Arlington, Arlington, Texas, USA
| | - Deng Mao
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Kevin S King
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Hanzhang Lu
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
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Busch J, Vannesjo SJ, Barmet C, Pruessmann KP, Kozerke S. Analysis of temperature dependence of background phase errors in phase-contrast cardiovascular magnetic resonance. J Cardiovasc Magn Reson 2014; 16:97. [PMID: 25497004 PMCID: PMC4263200 DOI: 10.1186/s12968-014-0097-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 11/14/2014] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND The accuracy of phase-contrast cardiovascular magnetic resonance (PC-CMR) can be compromised by background phase errors. It is the objective of the present work to provide an analysis of the temperature dependence of background phase errors in PC-CMR by means of gradient mount temperature sensing and magnetic field monitoring. METHODS Background phase errors were measured for various temperatures of the gradient mount using magnetic field monitoring and validated in a static phantom. The effect of thermal changes during k-space acquisition was simulated and confirmed with measurements in a stationary phantom. RESULTS The temperature of the gradient mount was found to increase by 20-30 K during PC-CMR measurements of 6-12 min duration. Associated changes in background phase errors of up to 11% or 0.35 radian were measured at 10 cm from the magnet's iso-center as a result of first order offsets. Zeroth order phase errors exhibited little thermal dependence. CONCLUSIONS It is concluded that changes in gradient mount temperature significantly modify background phase errors during PC-CMR with high gradient duty cycle. Since temperature increases significantly during the first minutes of scanning the results presented are also of relevance for single-slice or multi-slice PC-CMR scans. The findings prompt for further studies to investigate advanced correction methods taking into account gradient temperature and/or the use of concurrent field-monitoring to map gradient-induced fields throughout the scan.
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Affiliation(s)
- Julia Busch
- />Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - S Johanna Vannesjo
- />Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Christoph Barmet
- />Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland
- />Skope Magnetic Resonance Technologies, Zurich, Switzerland
| | - Klaas P Pruessmann
- />Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Sebastian Kozerke
- />Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland
- />Division of Imaging Science and Biomedical Engineering, King’s College London, London, UK
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Pineda Zapata JA, Delgado de Bedout JA, Rascovsky Ramírez S, Bustamante C, Mesa S, Calvo Betancur VD. A practical introduction to the hemodynamic analysis of the cardiovascular system with 4D Flow MRI. RADIOLOGIA 2014; 56:485-95. [PMID: 25447368 DOI: 10.1016/j.rx.2014.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 08/12/2014] [Accepted: 08/14/2014] [Indexed: 11/28/2022]
Abstract
The 4D Flow MRI technique provides a three-dimensional representation of blood flow over time, making it possible to evaluate the hemodynamics of the cardiovascular system both qualitatively and quantitatively. In this article, we describe the application of the 4D Flow technique in a 3T scanner; in addition to the technical parameters, we discuss the advantages and limitations of the technique and its possible clinical applications. We used 4D Flow MRI to study different body areas (chest, abdomen, neck, and head) in 10 volunteers. We obtained 3D representations of the patterns of flow and quantitative hemodynamic measurements. The technique makes it possible to evaluate the pattern of blood flow in large and midsize vessels without the need for exogenous contrast agents.
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Affiliation(s)
- J A Pineda Zapata
- Grupo de Investigación, Instituto de Alta Tecnología Médica (IATM), Medellín, Antioquia, Colombia.
| | - J A Delgado de Bedout
- Grupo de Investigación, Instituto de Alta Tecnología Médica (IATM), Medellín, Antioquia, Colombia
| | - S Rascovsky Ramírez
- Grupo de Investigación, Instituto de Alta Tecnología Médica (IATM), Medellín, Antioquia, Colombia
| | - C Bustamante
- Grupo de Investigación, Instituto de Alta Tecnología Médica (IATM), Medellín, Antioquia, Colombia
| | - S Mesa
- Universidad CES, Medellín, Antioquia, Colombia
| | - V D Calvo Betancur
- Grupo de Investigación, Instituto de Alta Tecnología Médica (IATM), Medellín, Antioquia, Colombia
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Zaman A, Motwani M, Oliver JJ, Crelier G, Dobson LE, Higgins DM, Plein S, Greenwood JP. 3.0T, time-resolved, 3D flow-sensitive MR in the thoracic aorta: Impact of k-t BLAST acceleration using 8- versus 32-channel coil arrays. J Magn Reson Imaging 2014; 42:495-504. [PMID: 25447784 DOI: 10.1002/jmri.24814] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 10/11/2014] [Indexed: 11/06/2022] Open
Abstract
PURPOSE To evaluate the performance of 4D flow MR in the thoracic aorta with 8- and 32-channel coil arrays using k-t BLAST and SENSE acceleration techniques and compare this to a conventional 2D SENSE approach. MATERIALS AND METHODS Fifteen healthy subjects and eight patients underwent magnetic resonance imaging (MRI) at 3.0T using: 1) 2D SENSE phase contrast velocity mapping as the reference standard and 2) 4D-flow pulse sequences accelerated with SENSE and k-t BLAST, using both 8- and 32-channel coil arrays. Data processing was performed using GT Flow. Image quality of the magnitude images and pathline visualization were graded and mean scan times, flow, peak velocity, stroke volume, and image quality were compared between techniques. RESULTS Mean scan times were significantly lower for 4D-flow sequences accelerated with k-t BLAST compared to SENSE (5.5 vs. 25.2 min; P < 0.01). 4D k-t BLAST acquisition had greater magnitude and pathline image quality than 4D SENSE acquisition for both 32-channel and 8-channel data (P < 0.001); both 4D SENSE and 4D k-t BLAST acquisitions had significantly greater image quality when 32 channels were utilized compared to 8 (P < 0.05). On Bland-Altman analysis, all 4D flow pulse sequences showed significant agreement with the 2D SENSE reference for peak velocity measurement (P > 0.05); the lowest bias being observed with the 4D 32 channel k-t BLAST sequence. There were no significant differences in measured flow, peak velocity, or stroke volume with any of the four investigated 4D acquisition techniques compared to reference technique values (P > 0.05). In patients, there were no significant differences in flow, peak velocity, or stroke volume measurements between 32-channel 4D k-t BLAST and the reference acquisition. CONCLUSION 4D flow MR using k-t BLAST and 32 channel coils allows a reduction in total scan time while improving overall image quality compared to a standard 2D SENSE and 4D SENSE acquisitions. The use of 32 channels rather than 8 channels with the 4D k-t BLAST was also preferable in terms of image quality.
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Affiliation(s)
- Arshad Zaman
- Multidisciplinary Cardiovascular Research Centre, Division of Cardiovascular and Diabetes Research, Leeds Institute of Genetics, Health & Therapeutics, University of Leeds, Leeds, UK
| | - Manish Motwani
- Multidisciplinary Cardiovascular Research Centre, Division of Cardiovascular and Diabetes Research, Leeds Institute of Genetics, Health & Therapeutics, University of Leeds, Leeds, UK
| | - James J Oliver
- Multidisciplinary Cardiovascular Research Centre, Division of Cardiovascular and Diabetes Research, Leeds Institute of Genetics, Health & Therapeutics, University of Leeds, Leeds, UK
| | - Gerard Crelier
- Institute for Biomedical Engineering, University and ETH Zurich, Switzerland
| | - Laura E Dobson
- Multidisciplinary Cardiovascular Research Centre, Division of Cardiovascular and Diabetes Research, Leeds Institute of Genetics, Health & Therapeutics, University of Leeds, Leeds, UK
| | | | - Sven Plein
- Multidisciplinary Cardiovascular Research Centre, Division of Cardiovascular and Diabetes Research, Leeds Institute of Genetics, Health & Therapeutics, University of Leeds, Leeds, UK
| | - John P Greenwood
- Multidisciplinary Cardiovascular Research Centre, Division of Cardiovascular and Diabetes Research, Leeds Institute of Genetics, Health & Therapeutics, University of Leeds, Leeds, UK
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Pineda Zapata J, Delgado de Bedout J, Rascovsky Ramírez S, Bustamante C, Mesa S, Calvo Betancur V. A practical introduction to the hemodynamic analysis of the cardiovascular system with 4D Flow MRI. RADIOLOGIA 2014. [DOI: 10.1016/j.rxeng.2014.08.001] [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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