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Nallamothu T, Pradella M, Markl M, Greenland P, Passman R, Elbaz MS. Robust and fast stochastic 4D flow vector-field signature technique for quantifying composite flow dynamics from 4D flow MRI: Application to left atrial flow in atrial fibrillation. Med Image Anal 2024; 92:103065. [PMID: 38113616 DOI: 10.1016/j.media.2023.103065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 11/09/2023] [Accepted: 12/11/2023] [Indexed: 12/21/2023]
Abstract
4D flow MRI is an emerging imaging modality that maps voxel-wise blood flow information as velocity vector fields that is acquired in 7-dimensional image volumes (3 spatial dimensions + 3 velocity directions + time). Blood flow in the cardiovascular system is often complex and composite involving multiple flow dynamics and patterns (e.g., vortex flow, jets, stagnating flow) that occur and interact simultaneously. The spectrum of such complex flow dynamics is embedded in the velocity vector field dynamics derived from 4D Flow MRI. However, current flow metrics cannot fully measure high-dimensional vector-field data and embedded complex composite flow data. Instead, these methods need to break down the vector-field data into secondary scalar fields of individual flow components using fluid dynamics operators. These methods are gradient-based and sensitive to data uncertainties, and only focus on individual flow components of the overall composite flow, therefore potentially underestimating the severity of overall flow changes associated with cardiovascular diseases. To address these limitations, in MICCAI 2021, we introduced a novel comprehensive stochastic 4D Flow vector-field signature technique that works directly on the entire spatiotemporal velocity vector field. This technique uses efficient stochastic gradient-free interrogation of multi-million flow vector-pairs per patient to derive the patient's unique flow profile of the complex composite flow alterations and in real-time processing. The signature technique's probabilistic gradient-free formulation should allow for highly robust quantification despite inherent errors in 4D flow MRI acquisitions. Here, we extend the application of the 4D flow vector-field signature technique to the left atrium to analyze complex composite flow changes in patients with atrial fibrillation. In 128 subjects, we performed extensive sensitivity testing and determined that the vector-field signature technique is highly robust to typical sources of data uncertainties in 4D flow MRI: degradation in spatiotemporal resolution, added Gaussian noise, and segmentation errors. We demonstrate the excellent generalizability of the stochastic convergence from the aorta to the left atrium and between different 4D Flow MRI acquisition protocols. We compare the robustness of our technique to existing advanced flow quantification metrics of kinetic energy, vorticity, and energy loss demonstrating a superior performance of up-to 14-fold. Our results show the potential diagnostic and clinical utility of our signature technique in identifying distinctly altered composite flow signatures in atrial fibrillation patients independent of existing flow metrics.
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Affiliation(s)
- Thara Nallamothu
- Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States; Biomedical Engineering, Northwestern University, Evanston, IL, United States
| | - Maurice Pradella
- Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States; Department of Radiology, Clinic of Radiology and Nuclear Medicine, University Hospital of Basel, Basel, Switzerland
| | - Michael Markl
- Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States; Biomedical Engineering, Northwestern University, Evanston, IL, United States
| | - Philip Greenland
- Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Rod Passman
- Cardiology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Mohammed Sm Elbaz
- Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States.
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2
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Runderkamp BA, Roos T, van der Zwaag W, Strijkers GJ, Caan MWA, Nederveen AJ. Whole-liver flip-angle shimming at 7 T using parallel-transmit k T -point pulses and Fourier phase-encoded DREAM B 1 + mapping. Magn Reson Med 2024; 91:75-90. [PMID: 37799015 DOI: 10.1002/mrm.29819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 06/18/2023] [Accepted: 07/13/2023] [Indexed: 10/07/2023]
Abstract
PURPOSE To obtain homogeneous signal throughout the human liver at 7 T. Flip angle (FA) shimming in 7T whole-liver imaging was performed through parallel-transmit kT -point pulses based on subject-specific multichannel absoluteB 1 + $$ {\mathrm{B}}_1^{+} $$ maps from Fourier phase-encoded dual refocusing echo acquisition mode (PE-DREAM). METHODS The optimal number of Fourier phase-encoding steps for PE-DREAMB 1 + $$ {\mathrm{B}}_1^{+} $$ mapping was determined for a 7T eight-channel parallel-transmission system. FA shimming experiments were performed in the liver of 7 healthy subjects with varying body mass index. In these subjects, firstB 0 $$ {\mathrm{B}}_0 $$ shimming and Fourier PE-DREAMB 1 + $$ {\mathrm{B}}_1^{+} $$ mapping were performed. Subsequently, three small-flip-angle 3D gradient-echo scans were acquired, comparing a circularly polarized (CP) mode, a phase shim, and a kT -point pulse. Resulting homogeneity was assessed and compared with estimated FA maps and distributions. RESULTS Fourier PE-DREAM with 13 phase-encoding steps resulted in a good tradeoff betweenB 1 + $$ {\mathrm{B}}_1^{+} $$ accuracy and scan time. Lower coefficient of variation values (average [min-max] across subjects) of the estimated FA in the volume of interest were observed using kT -points (7.4 [6.6%-8.0%]), compared with phase shimming (18.8 [12.9%-23.4%], p < 0.001) and CP (43.2 [39.4%-47.1%], p < 0.001). kT -points delivered whole-liver images with the nominal FA and the highest degree of homogeneity. CP and phase shimming resulted in either inaccurate or imprecise FA distributions. Here, locations having suboptimal FA in the estimated FA maps corresponded to liver areas suffering from inconsistent signal intensity and T1 -weighting in the gradient-echo scans. CONCLUSION Homogeneous whole-liver 3D gradient-echo acquisitions at 7 T can be obtained with eight-channel kT -point pulses calculated based on subject-specific multichannel absolute Fourier PE-DREAMB 1 + $$ {\mathrm{B}}_1^{+} $$ maps.
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Affiliation(s)
- Bobby A Runderkamp
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, the Netherlands
| | - Thomas Roos
- Spinoza Centre for Neuroimaging, Royal Netherlands Academy for Arts and Sciences (KNAW), Amsterdam, the Netherlands
- High-Field Research Group, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Wietske van der Zwaag
- Spinoza Centre for Neuroimaging, Royal Netherlands Academy for Arts and Sciences (KNAW), Amsterdam, the Netherlands
- Computational and Cognitive Neuroscience and Neuroimaging, Netherlands Institute for Neuroscience, KNAW, Amsterdam, the Netherlands
| | - Gustav J Strijkers
- Department of Biomedical Engineering and Physics, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands
| | - Matthan W A Caan
- Department of Biomedical Engineering and Physics, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands
| | - Aart J Nederveen
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, the Netherlands
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Li N, Tous C, Dimov IP, Fei P, Zhang Q, Lessard S, Tang A, Martel S, Soulez G. Design of a Low-Cost, Self-Adaptive and MRI-Compatible Cardiac Gating System. IEEE Trans Biomed Eng 2023; 70:3126-3136. [PMID: 37276095 DOI: 10.1109/tbme.2023.3280348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
OBJECTIVE Cardiac gating, synchronizing medical scans with cardiac activity, is widely used to make quantitative measurements of physiological events and to obtain high-quality scans free of pulsatile artefacts. This can provide important information for disease diagnosis, targeted control of medical microrobots, etc. The current work proposes a low-cost, self-adaptive, MRI-compatible cardiac gating system. METHOD The system and its processing algorithm, based on the monitoring and analysis of blood pressure waveforms, are proposed. The system is tested in an in vitro experiment and two living pigs using four-dimensional (4D) flow magnetic resonance imaging (MRI) and two-dimensional phase-contrast (2D-PC) sequences. RESULTS in vitro and in vivo experiments reveal that the proposed system can provide stable cardiac synchronicity, has good MRI compatibility, and can cope with the fringe magnetic field of the MRI scanner, radiofrequency signals during image acquisition, and heart rate changes. High-resolution 4D flow imaging is successfully acquired both in vivo and in vitro. The difference between the 2D and 4D measurements is ≤ 21%. The incidence of false triggers is 0% in all tests, which is unattainable for other known cardiac gating methods. CONCLUSION The system has good MRI compatibility and can provide a stable and accurate trigger signal based on pressure waveform. It opens the door to applications where the previous gating methods were difficult to implement or not applicable.
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Bissell MM, Raimondi F, Ait Ali L, Allen BD, Barker AJ, Bolger A, Burris N, Carhäll CJ, Collins JD, Ebbers T, Francois CJ, Frydrychowicz A, Garg P, Geiger J, Ha H, Hennemuth A, Hope MD, Hsiao A, Johnson K, Kozerke S, Ma LE, Markl M, Martins D, Messina M, Oechtering TH, van Ooij P, Rigsby C, Rodriguez-Palomares J, Roest AAW, Roldán-Alzate A, Schnell S, Sotelo J, Stuber M, Syed AB, Töger J, van der Geest R, Westenberg J, Zhong L, Zhong Y, Wieben O, Dyverfeldt P. 4D Flow cardiovascular magnetic resonance consensus statement: 2023 update. J Cardiovasc Magn Reson 2023; 25:40. [PMID: 37474977 PMCID: PMC10357639 DOI: 10.1186/s12968-023-00942-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 05/30/2023] [Indexed: 07/22/2023] Open
Abstract
Hemodynamic assessment is an integral part of the diagnosis and management of cardiovascular disease. Four-dimensional cardiovascular magnetic resonance flow imaging (4D Flow CMR) allows comprehensive and accurate assessment of flow in a single acquisition. This consensus paper is an update from the 2015 '4D Flow CMR Consensus Statement'. We elaborate on 4D Flow CMR sequence options and imaging considerations. The document aims to assist centers starting out with 4D Flow CMR of the heart and great vessels with advice on acquisition parameters, post-processing workflows and integration into clinical practice. Furthermore, we define minimum quality assurance and validation standards for clinical centers. We also address the challenges faced in quality assurance and validation in the research setting. We also include a checklist for recommended publication standards, specifically for 4D Flow CMR. Finally, we discuss the current limitations and the future of 4D Flow CMR. This updated consensus paper will further facilitate widespread adoption of 4D Flow CMR in the clinical workflow across the globe and aid consistently high-quality publication standards.
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Affiliation(s)
- Malenka M Bissell
- Department of Biomedical Imaging Science, Leeds Institute of Cardiovascular and Metabolic Medicine (LICAMM), LIGHT Laboratories, Clarendon Way, University of Leeds, Leeds, LS2 9NL, UK.
| | | | - Lamia Ait Ali
- Institute of Clinical Physiology CNR, Massa, Italy
- Foundation CNR Tuscany Region G. Monasterio, Massa, Italy
| | - Bradley D Allen
- Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Alex J Barker
- Department of Radiology, Children's Hospital Colorado, University of Colorado Anschutz Medical Center, Aurora, USA
| | - Ann Bolger
- Department of Medicine, University of California, San Francisco, CA, USA
- Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
| | - Nicholas Burris
- Department of Radiology, University of Michigan, Ann Arbor, USA
| | - Carl-Johan Carhäll
- Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | | | - Tino Ebbers
- Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
| | | | - Alex Frydrychowicz
- Department of Radiology and Nuclear Medicine, University Hospital Schleswig-Holstein, Campus Lübeck and Universität Zu Lübeck, Lübeck, Germany
| | - Pankaj Garg
- Norwich Medical School, University of East Anglia, Norwich, UK
| | - Julia Geiger
- Department of Diagnostic Imaging, University Children's Hospital, Zurich, Switzerland
- Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland
| | - Hojin Ha
- Department of Mechanical and Biomedical Engineering, Kangwon National University, Chuncheon, South Korea
| | - Anja Hennemuth
- Institute of Computer-Assisted Cardiovascular Medicine, Charité - Universitätsmedizin, Berlin, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site, Berlin, Germany
- Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Michael D Hope
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA
| | - Albert Hsiao
- Department of Radiology, University of California, San Diego, CA, USA
| | - Kevin Johnson
- Departments of Radiology and Medical Physics, University of Wisconsin, Madison, WI, USA
| | - Sebastian Kozerke
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - Liliana E Ma
- Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Michael Markl
- Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Duarte Martins
- Department of Pediatric Cardiology, Hospital de Santa Cruz, Centro Hospitalar Lisboa Ocidental, Lisbon, Portugal
| | - Marci Messina
- Department of Radiology, Northwestern Medicine, Chicago, IL, USA
| | - Thekla H Oechtering
- Department of Radiology and Nuclear Medicine, University Hospital Schleswig-Holstein, Campus Lübeck and Universität Zu Lübeck, Lübeck, Germany
- Departments of Radiology and Medical Physics, University of Wisconsin, Madison, WI, USA
| | - Pim van Ooij
- Department of Radiology & Nuclear Medicine, Amsterdam Cardiovascular Sciences, Amsterdam Movement Sciences, Amsterdam University Medical Centers, Location AMC, Amsterdam, The Netherlands
- Department of Pediatric Cardiology, Division of Pediatrics, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Cynthia Rigsby
- Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
- Department of Medical Imaging, Ann & Robert H Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Jose Rodriguez-Palomares
- Department of Cardiology, Hospital Universitari Vall d´Hebron,Vall d'Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red-CV, CIBER CV, Madrid, Spain
| | - Arno A W Roest
- Department of Pediatric Cardiology, Willem-Alexander's Children Hospital, Leiden University Medical Center and Center for Congenital Heart Defects Amsterdam-Leiden, Leiden, The Netherlands
| | | | - Susanne Schnell
- Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
- Department of Medical Physics, Institute of Physics, University of Greifswald, Greifswald, Germany
| | - Julio Sotelo
- School of Biomedical Engineering, Universidad de Valparaíso, Valparaíso, Chile
- Biomedical Imaging Center, Pontificia Universidad Catolica de Chile, Santiago, Chile
- Millennium Institute for Intelligent Healthcare Engineering - iHEALTH, Santiago, Chile
| | - Matthias Stuber
- Département de Radiologie Médicale, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Ali B Syed
- Department of Radiology, Stanford University, Stanford, CA, USA
| | - Johannes Töger
- Clinical Physiology, Department of Clinical Sciences Lund, Lund University, Skåne University Hospital, Lund, Sweden
| | - Rob van der Geest
- Division of Image Processing, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Jos Westenberg
- CardioVascular Imaging Group (CVIG), Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Liang Zhong
- National Heart Centre Singapore, Duke-NUS Medical School, National University of Singapore, Singapore, Singapore
| | - Yumin Zhong
- Department of Radiology, School of Medicine, Shanghai Children's Medical Center Affiliated With Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Oliver Wieben
- Departments of Radiology and Medical Physics, University of Wisconsin, Madison, WI, USA
| | - Petter Dyverfeldt
- Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
- Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
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Ramaekers MJFG, Westenberg JJM, Adriaans BP, Nijssen EC, Wildberger JE, Lamb HJ, Schalla S. A clinician's guide to understanding aortic 4D flow MRI. Insights Imaging 2023; 14:114. [PMID: 37395817 DOI: 10.1186/s13244-023-01458-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 06/03/2023] [Indexed: 07/04/2023] Open
Abstract
Four-dimensional flow magnetic resonance imaging is an emerging technique which may play a role in diagnosis and risk-stratification of aortic disease. Some knowledge of flow dynamics and related parameters is necessary to understand and apply this technique in clinical workflows. The purpose of the current review is to provide a guide for clinicians to the basics of flow imaging, frequently used flow-related parameters, and their relevance in the context of aortic disease.Clinical relevance statement Understanding normal and abnormal aortic flow could improve clinical care in patients with aortic disease.
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Affiliation(s)
- Mitch J F G Ramaekers
- Department of Cardiology and Radiology and Nuclear Medicine, Maastricht University Medical Center +, P. Debyelaan 25, 6229 HX, Maastricht, The Netherlands.
- Cardiovascular Research Institute Maastricht (CARIM), Maastricht, The Netherlands.
- Department of Radiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands.
| | - Jos J M Westenberg
- Department of Radiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | - Bouke P Adriaans
- Department of Cardiology and Radiology and Nuclear Medicine, Maastricht University Medical Center +, P. Debyelaan 25, 6229 HX, Maastricht, The Netherlands
- Cardiovascular Research Institute Maastricht (CARIM), Maastricht, The Netherlands
| | - Estelle C Nijssen
- Cardiovascular Research Institute Maastricht (CARIM), Maastricht, The Netherlands
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Center +, P. Debyelaan 25, 6229 HX, Maastricht, The Netherlands
| | - Joachim E Wildberger
- Cardiovascular Research Institute Maastricht (CARIM), Maastricht, The Netherlands
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Center +, P. Debyelaan 25, 6229 HX, Maastricht, The Netherlands
| | - Hildo J Lamb
- Department of Radiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA, Leiden, The Netherlands
| | - Simon Schalla
- Cardiovascular Research Institute Maastricht (CARIM), Maastricht, The Netherlands
- Department of Cardiology, Maastricht University Medical Center +, P. Debyelaan 25, 6229 HX, Maastricht, The Netherlands
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Shaffer A, Nigh N, Weisbaum D, Anderson A, Wszalek T, Sutton BP, Webb A, Damon B, Moussa I, Arnold PM. Cardiothoracic and Vascular Surgery Implant Compatibility With Ultrahigh Field Magnetic Resonance Imaging (4.7 Tesla and 7 Tesla). Am J Cardiol 2023; 201:239-246. [PMID: 37392607 DOI: 10.1016/j.amjcard.2023.05.062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 05/23/2023] [Accepted: 05/31/2023] [Indexed: 07/03/2023]
Abstract
The use of 7 Tesla (T) magnetic resonance imaging (MRI) is expanding across medical specialties, particularly, clinical neurosciences and orthopedics. Investigational 7 T MRI has also been performed in cardiology. A limiting factor for expansion of the role of 7 T, irrespective of the body part being imaged, is the sparse testing of biomedical implant compatibility at field strengths >3 T. Implant compatibility can be tested following the American Society for Testing and Materials International guidelines. To assess the current state of cardiovascular implant safety at field strengths >3 T, a systematic search was performed using PubMed, Web of Science, and citation matching. Studies written in English that included at least 1 cardiovascular-related implant and at least 1 safety outcome (deflection angle, torque, or temperature change) were included. Data were extracted for the implant studied, implant composition, deflection angle, torque, and temperature change, and the American Society for Testing and Materials International standards were followed. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guidelines for scoping reviews were followed. A total of 9 studies were included. A total of 34 cardiovascular-related implants tested ex vivo at 7 T and 91 implants tested ex vivo at 4.7 T were included. The implants included vascular grafts and conduits, vascular access ports, peripheral and coronary stents, caval filters, and artificial valves. A total of 2 grafts, 1 vascular access port, 2 vena cava filters, and 5 stents were identified as incompatible with the 7 T MRI. All incompatible stents were 40 mm in length. Based on the safety outcomes reported, we identify several implants that may be compatible with >3 T MRI. This scoping review seeks to concisely summarize all the cardiovascular-related implants tested for ultrahigh field MRI compatibility to date.
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Affiliation(s)
- Annabelle Shaffer
- Carle Illinois College of Medicine, University of Illinois Urbana Champaign, Urbana, Illinois
| | - Noah Nigh
- Carle Illinois College of Medicine, University of Illinois Urbana Champaign, Urbana, Illinois
| | - David Weisbaum
- Department of Neurosurgery, Carle Foundation Hospital, Urbana, Illinois
| | - Aaron Anderson
- Carle Illinois Advanced Imaging Center, Carle Foundation Hospital, Urbana, Illinois; Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Tracey Wszalek
- Carle Illinois Advanced Imaging Center, Carle Foundation Hospital, Urbana, Illinois; Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Bradley P Sutton
- Carle Illinois College of Medicine, University of Illinois Urbana Champaign, Urbana, Illinois; Carle Illinois Advanced Imaging Center, Carle Foundation Hospital, Urbana, Illinois; Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Andrew Webb
- Carle Illinois Advanced Imaging Center, Carle Foundation Hospital, Urbana, Illinois; Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands; Leiden University Medical Center, Leiden, The Netherlands
| | - Bruce Damon
- Carle Illinois Advanced Imaging Center, Carle Foundation Hospital, Urbana, Illinois; Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Issam Moussa
- Carle Illinois College of Medicine, University of Illinois Urbana Champaign, Urbana, Illinois; Heart and Vascular Institute, Carle Foundation Hospital, Urbana, Illinois
| | - Paul M Arnold
- Carle Illinois College of Medicine, University of Illinois Urbana Champaign, Urbana, Illinois; Department of Neurosurgery, Carle Foundation Hospital, Urbana, Illinois.
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Righini P, Secchi F, Mazzaccaro D, Giese D, Galligani M, Avishay D, Capra D, Monti CB, Nano G. Four-Dimensional Flow MRI for the Evaluation of Aortic Endovascular Graft: A Pilot Study. Diagnostics (Basel) 2023; 13:2113. [PMID: 37371010 DOI: 10.3390/diagnostics13122113] [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: 04/27/2023] [Revised: 05/28/2023] [Accepted: 06/15/2023] [Indexed: 06/29/2023] Open
Abstract
We aimed to explore the feasibility of 4D flow magnetic resonance imaging (MRI) for patients undergoing thoracic aorta endovascular repair (TEVAR). We retrospectively evaluated ten patients (two female), with a mean (±standard deviation) age of 61 ± 20 years, undergoing MRI for a follow-up after TEVAR. All 4D flow examinations were performed using a 1.5-T system (MAGNETOM Aera, Siemens Healthcare, Erlangen, Germany). In addition to the standard examination protocol, a 4D flow-sensitive 3D spatial-encoding, time-resolved, phase-contrast prototype sequence was acquired. Among our cases, flow evaluation was feasible in all patients, although we observed some artifacts in 3 out of 10 patients. Three individuals displayed a reduced signal within the vessel lumen where the endograft was placed, while others presented with turbulent or increased flow. An aortic endograft did not necessarily hinder the visualization of blood flow through 4D flow sequences, although the graft could generate flow artifacts in some cases. A 4D Flow MRI may represent the ideal tool to follow up on both healthy subjects deemed to be at an increased risk based on their anatomical characteristics or patients submitted to TEVAR for whom a surveillance protocol with computed tomography angiography would be cumbersome and unjustified.
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Affiliation(s)
- Paolo Righini
- Operative Unit of Vascular & Endovascular Unit, IRCCS Policlinico San Donato, Via Morandi 30, 20097 San Donato Milanese, Italy
| | - Francesco Secchi
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Via Mangiagalli 31, 20133 Milano, Italy
- Unit of Radiology, IRCCS Policlinico San Donato, Via Morandi 30, 20097 San Donato Milanese, Italy
| | - Daniela Mazzaccaro
- Operative Unit of Vascular & Endovascular Unit, IRCCS Policlinico San Donato, Via Morandi 30, 20097 San Donato Milanese, Italy
| | - Daniel Giese
- Magnetic Resonance, Siemens Healthcare GmbH, 91050 Erlangen, Germany
| | - Marina Galligani
- Operative Unit of Vascular & Endovascular Unit, IRCCS Policlinico San Donato, Via Morandi 30, 20097 San Donato Milanese, Italy
| | - Dor Avishay
- Operative Unit of Vascular & Endovascular Unit, IRCCS Policlinico San Donato, Via Morandi 30, 20097 San Donato Milanese, Italy
| | - Davide Capra
- Postgraduation School in Radiodiagnostics, Università degli Studi di Milano, Via Festa del Perdono 7, 20122 Milano, Italy
| | - Caterina Beatrice Monti
- Postgraduation School in Radiodiagnostics, Università degli Studi di Milano, Via Festa del Perdono 7, 20122 Milano, Italy
| | - Giovanni Nano
- Operative Unit of Vascular & Endovascular Unit, IRCCS Policlinico San Donato, Via Morandi 30, 20097 San Donato Milanese, Italy
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Via Mangiagalli 31, 20133 Milano, Italy
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8
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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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Krueger F, Aigner CS, Hammernik K, Dietrich S, Lutz M, Schulz-Menger J, Schaeffter T, Schmitter S. Rapid estimation of 2D relative B 1 + -maps from localizers in the human heart at 7T using deep learning. Magn Reson Med 2023; 89:1002-1015. [PMID: 36336877 DOI: 10.1002/mrm.29510] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 10/11/2022] [Accepted: 10/11/2022] [Indexed: 11/09/2022]
Abstract
PURPOSE Subject-tailored parallel transmission pulses for ultra-high fields body applications are typically calculated based on subject-specific B 1 + $$ {\mathrm{B}}_1^{+} $$ -maps of all transmit channels, which require lengthy adjustment times. This study investigates the feasibility of using deep learning to estimate complex, channel-wise, relative 2D B 1 + $$ {\mathrm{B}}_1^{+} $$ -maps from a single gradient echo localizer to overcome long calibration times. METHODS 126 channel-wise, complex, relative 2D B 1 + $$ {\mathrm{B}}_1^{+} $$ -maps of the human heart from 44 subjects were acquired at 7T using a Cartesian, cardiac gradient-echo sequence obtained under breath-hold to create a library for network training and cross-validation. The deep learning predicted maps were qualitatively compared to the ground truth. Phase-only B 1 + $$ {\mathrm{B}}_1^{+} $$ -shimming was subsequently performed on the estimated B 1 + $$ {\mathrm{B}}_1^{+} $$ -maps for a region of interest covering the heart. The proposed network was applied at 7T to 3 unseen test subjects. RESULTS The deep learning-based B 1 + $$ {\mathrm{B}}_1^{+} $$ -maps, derived in approximately 0.2 seconds, match the ground truth for the magnitude and phase. The static, phase-only pulse design performs best when maximizing the mean transmission efficiency. In-vivo application of the proposed network to unseen subjects demonstrates the feasibility of this approach: the network yields predicted B 1 + $$ {\mathrm{B}}_1^{+} $$ -maps comparable to the acquired ground truth and anatomical scans reflect the resulting B 1 + $$ {\mathrm{B}}_1^{+} $$ -pattern using the deep learning-based maps. CONCLUSION The feasibility of estimating 2D relative B 1 + $$ {\mathrm{B}}_1^{+} $$ -maps from initial localizer scans of the human heart at 7T using deep learning is successfully demonstrated. Because the technique requires only sub-seconds to derive channel-wise B 1 + $$ {\mathrm{B}}_1^{+} $$ -maps, it offers high potential for advancing clinical body imaging at ultra-high fields.
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Affiliation(s)
- Felix Krueger
- Physikalisch-Technische Bundesanstalt, Braunschweig and Berlin, Germany.,Technische Universität Berlin, Biomedical Engineering, Berlin, Germany
| | | | - Kerstin Hammernik
- Technical University of Munich, Munich, Germany.,Imperial College London, London, United Kingdom
| | | | - Max Lutz
- Physikalisch-Technische Bundesanstalt, Braunschweig and Berlin, Germany
| | - Jeanette Schulz-Menger
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität Zu Berlin, Experimental Clinical Research Center, Berlin, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany.,Department of Cardiology and Nephrology, HELIOS Hospital Berlin-Buch, Berlin, Germany
| | - Tobias Schaeffter
- Physikalisch-Technische Bundesanstalt, Braunschweig and Berlin, Germany.,Technische Universität Berlin, Biomedical Engineering, Berlin, Germany.,Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom
| | - Sebastian Schmitter
- Physikalisch-Technische Bundesanstalt, Braunschweig and Berlin, Germany.,Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota, USA.,Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
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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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11
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Varga-Szemes A, Halfmann M, Schoepf UJ, Jin N, Kilburg A, Dargis DM, Düber C, Ese A, Aquino G, Xiong F, Kreitner KF, Markl M, Emrich T. Highly Accelerated Compressed-Sensing 4D Flow for Intracardiac Flow Assessment. J Magn Reson Imaging 2022. [PMID: 36264176 DOI: 10.1002/jmri.28484] [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: 08/02/2022] [Revised: 10/03/2022] [Accepted: 10/04/2022] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Four-dimensional (4D) flow MRI allows for the quantification of complex flow patterns; however, its clinical use is limited by its inherently long acquisition time. Compressed sensing (CS) is an acceleration technique that provides substantial reduction in acquisition time. PURPOSE To compare intracardiac flow measurements between conventional and CS-based highly accelerated 4D flow acquisitions. STUDY TYPE Prospective. SUBJECTS Fifty healthy volunteers (28.0 ± 7.1 years, 24 males). FIELD STRENGTH/SEQUENCE Whole heart time-resolved 3D gradient echo with three-directional velocity encoding (4D flow) with conventional parallel imaging (factor 3) as well as CS (factor 7.7) acceleration at 3 T. ASSESSMENT 4D flow MRI data were postprocessed by applying a valve tracking algorithm. Acquisition times, flow volumes (mL/cycle) and diastolic function parameters (ratio of early to late diastolic left ventricular peak velocities [E/A] and ratio of early mitral inflow velocity to mitral annular early diastolic velocity [E/e']) were quantified by two readers. STATISTICAL TESTS Paired-samples t-test and Wilcoxon rank sum test to compare measurements. Pearson correlation coefficient (r), Bland-Altman-analysis (BA) and intraclass correlation coefficient (ICC) to evaluate agreement between techniques and readers. A P value < 0.05 was considered statistically significant. RESULTS A significant improvement in acquisition time was observed using CS vs. conventional accelerated acquisition (6.7 ± 1.3 vs. 12.0 ± 1.3 min). Net forward flow measurements for all valves showed good correlation (r > 0.81) and agreement (ICCs > 0.89) between conventional and CS acceleration, with 3.3%-8.3% underestimation by the CS technique. Evaluation of diastolic function showed 3.2%-17.6% error: E/A 2.2 [1.9-2.4] (conventional) vs. 2.3 [2.0-2.6] (CS), BA bias 0.08 [-0.81-0.96], ICC 0.82; and E/e' 4.6 [3.9-5.4] (conventional) vs. 3.8 [3.4-4.3] (CS), BA bias -0.90 [-2.31-0.50], ICC 0.89. DATA CONCLUSION Analysis of intracardiac flow patterns and evaluation of diastolic function using a highly accelerated 4D flow sequence prototype is feasible, but it shows underestimation of flow measurements by approximately 10%. EVIDENCE LEVEL 2 TECHNICAL EFFICACY: Stage 1.
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Affiliation(s)
- Akos Varga-Szemes
- Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, South Carolina
| | - Moritz Halfmann
- Department of Diagnostic and Interventional Radiology, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany.,German Centre for Cardiovascular Research, Partner site Rhine-Main, Mainz, Germany
| | - U Joseph Schoepf
- Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, South Carolina
| | - Ning Jin
- Siemens Medical Solutions USA Inc., Chicago, Illinois, USA
| | - Anton Kilburg
- Department of Diagnostic and Interventional Radiology, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Danielle M Dargis
- Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, South Carolina
| | - Christoph Düber
- Department of Diagnostic and Interventional Radiology, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Amir Ese
- Department of Diagnostic and Interventional Radiology, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Gilberto Aquino
- Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, South Carolina
| | - Fei Xiong
- Siemens Medical Solutions USA Inc., Chicago, Illinois, USA
| | - Karl-Friedrich Kreitner
- Department of Diagnostic and Interventional Radiology, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Michael Markl
- Department of Radiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA.,Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, Illinois, USA
| | - Tilman Emrich
- Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, South Carolina.,Department of Diagnostic and Interventional Radiology, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany.,German Centre for Cardiovascular Research, Partner site Rhine-Main, Mainz, Germany
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12
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Dimov IP, Tous C, Li N, Barat M, Bomberna T, Debbaut C, Jin N, Moran G, Tang A, Soulez G. Assessment of hepatic arterial hemodynamics with 4D flow MRI: in vitro analysis of motion and spatial resolution related error and in vivo feasibility study in 20 volunteers. Eur Radiol 2022; 32:8639-8648. [PMID: 35731288 DOI: 10.1007/s00330-022-08890-5] [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: 01/25/2022] [Revised: 04/25/2022] [Accepted: 05/17/2022] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To assess the ability of four-dimensional (4D) flow MRI to measure hepatic arterial hemodynamics by determining the effects of spatial resolution and respiratory motion suppression in vitro and its applicability in vivo with comparison to two-dimensional (2D) phase-contrast MRI. METHODS A dynamic hepatic artery phantom and 20 consecutive volunteers were scanned. The accuracies of Cartesian 4D flow sequences with k-space reordering and navigator gating at four spatial resolutions (0.5- to 1-mm isotropic) and navigator acceptance windows (± 8 to ± 2 mm) and one 2D phase-contrast sequence (0.5-mm in -plane) were assessed in vitro at 3 T. Two sequences centered on gastroduodenal and hepatic artery branches were assessed in vivo for intra - and interobserver agreement and compared to 2D phase-contrast. RESULTS In vitro, higher spatial resolution led to a greater decrease in error than narrower navigator window (30.5 to -4.67% vs -6.64 to -4.67% for flow). In vivo, hepatic and gastroduodenal arteries were more often visualized with the higher resolution sequence (90 vs 71%). Despite similar interobserver agreement (κ = 0.660 and 0.704), the higher resolution sequence had lower variability for area (CV = 20.04 vs 30.67%), flow (CV = 34.92 vs 51.99%), and average velocity (CV = 26.47 vs 44.76%). 4D flow had lower differences between inflow and outflow at the hepatic artery bifurcation (11.03 ± 5.05% and 15.69 ± 6.14%) than 2D phase-contrast (28.77 ± 21.01%). CONCLUSION High-resolution 4D flow can assess hepatic artery anatomy and hemodynamics with improved accuracy, greater vessel visibility, better interobserver reliability, and internal consistency. KEY POINTS • Motion-suppressed Cartesian four-dimensional (4D) flow MRI with higher spatial resolution provides more accurate measurements even when accepted respiratory motion exceeds voxel size. • 4D flow MRI with higher spatial resolution provides substantial interobserver agreement for visualization of hepatic artery branches. • Lower peak and average velocities and a trend toward better internal consistency were observed with 4D flow MRI as compared to 2D phase-contrast.
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Affiliation(s)
- Ivan P Dimov
- Laboratory of Clinical Image Processing (LCTI), Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900, rue Saint-Denis, Pavillon R, Montreal, QC, H2X 0A9, Canada
| | - Cyril Tous
- Laboratory of Clinical Image Processing (LCTI), Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900, rue Saint-Denis, Pavillon R, Montreal, QC, H2X 0A9, Canada
| | - Ning Li
- Laboratory of Clinical Image Processing (LCTI), Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900, rue Saint-Denis, Pavillon R, Montreal, QC, H2X 0A9, Canada
| | - Maxime Barat
- Laboratory of Clinical Image Processing (LCTI), Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900, rue Saint-Denis, Pavillon R, Montreal, QC, H2X 0A9, Canada.,Department of Radiology and Nuclear Medicine, Centre Hospitalier de l'Université de Montréal (CHUM), Montreal, QC, Canada
| | - Tim Bomberna
- IBiTech-Biommeda, Department of Electronics and Information Systems, Ghent University, Ghent, Belgium.,Cancer Research Institute Ghent (CRIG), Ghent University, Ghent, Belgium
| | - Charlotte Debbaut
- IBiTech-Biommeda, Department of Electronics and Information Systems, Ghent University, Ghent, Belgium.,Cancer Research Institute Ghent (CRIG), Ghent University, Ghent, Belgium
| | - Ning Jin
- Cardiovascular MR R&D, Siemens Medical Solutions USA, Inc., Cleveland, OH, USA
| | - Gerald Moran
- Siemens Healthineers Canada, Oakville, ON, Canada
| | - An Tang
- Laboratory of Clinical Image Processing (LCTI), Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900, rue Saint-Denis, Pavillon R, Montreal, QC, H2X 0A9, Canada.,Department of Radiology and Nuclear Medicine, Centre Hospitalier de l'Université de Montréal (CHUM), Montreal, QC, Canada.,Department of Radiology, Radiation Oncology and Nuclear Medicine, Faculty of Medecine, Université de Montréal, 2900 Bd Edouard-Montpetit , Montreal, QC, H3T 1J4, Canada
| | - Gilles Soulez
- Laboratory of Clinical Image Processing (LCTI), Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900, rue Saint-Denis, Pavillon R, Montreal, QC, H2X 0A9, Canada. .,Department of Radiology and Nuclear Medicine, Centre Hospitalier de l'Université de Montréal (CHUM), Montreal, QC, Canada. .,Department of Radiology, Radiation Oncology and Nuclear Medicine, Faculty of Medecine, Université de Montréal, 2900 Bd Edouard-Montpetit , Montreal, QC, H3T 1J4, Canada.
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13
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Töger J, Andersen M, Haglund O, Kylkilahti TM, Lundgaard I, Markenroth Bloch K. Real‐time imaging of respiratory effects on cerebrospinal fluid flow in small diameter passageways. Magn Reson Med 2022; 88:770-786. [PMID: 35403247 PMCID: PMC9324219 DOI: 10.1002/mrm.29248] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 03/01/2022] [Accepted: 03/08/2022] [Indexed: 12/03/2022]
Abstract
Purpose Respiration‐related CSF flow through the cerebral aqueduct may be useful for elucidating physiology and pathophysiology of the glymphatic system, which has been proposed as a mechanism of brain waste clearance. Therefore, we aimed to (1) develop a real‐time (CSF) flow imaging method with high spatial and sufficient temporal resolution to capture respiratory effects, (2) validate the method in a phantom setup and numerical simulations, and (3) apply the method in vivo and quantify its repeatability and correlation with different respiratory conditions. Methods A golden‐angle radial flow sequence (reconstructed temporal resolution 168 ms, spatial resolution 0.6 mm) was implemented on a 7T MRI scanner and reconstructed using compressed sensing. A phantom setup mimicked simultaneous cardiac and respiratory flow oscillations. The effect of temporal resolution and vessel diameter was investigated numerically. Healthy volunteers (n = 10) were scanned at four different respiratory conditions, including repeat scans. Results Phantom data show that the developed sequence accurately quantifies respiratory oscillations (ratio real‐time/reference QR = 0.96 ± 0.02), but underestimates the rapid cardiac oscillations (ratio QC = 0.46 ± 0.14). Simulations suggest that QC can be improved by increasing temporal resolution. In vivo repeatability was moderate to very strong for cranial and caudal flow (intraclass correlation coefficient range: 0.55–0.99) and weak to strong for net flow (intraclass correlation coefficient range: 0.48–0.90). Net flow was influenced by respiratory condition (p < 0.01). Conclusions The presented real‐time flow MRI method can quantify respiratory‐related variations of CSF flow in the cerebral aqueduct, but it underestimates rapid cardiac oscillations. In vivo, the method showed good repeatability and a relationship between flow and respiration.
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Affiliation(s)
- Johannes Töger
- Department of Clinical Sciences Lund, Diagnostic Radiology Lund University, Skåne University Hospital Lund Sweden
| | - Mads Andersen
- Philips Healthcare Copenhagen Denmark
- Lund University, Lund University Bioimaging Center Lund Sweden
| | - Olle Haglund
- Department of Medical Radiation Physics Lund University Lund Sweden
| | - Tekla Maria Kylkilahti
- Department of Experimental Medical Science Lund University Lund Sweden
- Wallenberg Centre for Molecular Medicine Lund University Lund Sweden
| | - Iben Lundgaard
- Department of Experimental Medical Science Lund University Lund Sweden
- Wallenberg Centre for Molecular Medicine Lund University Lund Sweden
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14
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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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15
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Isoda H, Fukuyama A. Quality Control for 4D Flow MR Imaging. Magn Reson Med Sci 2022; 21:278-292. [PMID: 35197395 PMCID: PMC9680545 DOI: 10.2463/mrms.rev.2021-0165] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 01/08/2022] [Indexed: 01/06/2023] Open
Abstract
In recent years, 4D flow MRI has become increasingly important in clinical applications for the blood vessels in the whole body, heart, and cerebrospinal fluid. 4D flow MRI has advantages over 2D cine phase-contrast (PC) MRI in that any targeted area of interest can be analyzed post-hoc, but there are some factors to be considered, such as ensuring measurement accuracy, a long imaging time and post-processing complexity, and interobserver variability.Due to the partial volume phenomenon caused by low spatial and temporal resolutions, the accuracy of flow measurement in 4D flow MRI is reduced. For spatial resolution, it is recommended to include at least four voxels in the vessel of interest, and if possible, six voxels. In large vessels such as the aorta, large voxels can be secured and SNR can be maintained, but in small cerebral vessels, SNR is reduced, resulting in reduced accuracy. A temporal resolution of less than 40 ms is recommended. The velocity-to-noise ratio (VNR) of low-velocity blood flow is low, resulting in poor measurement accuracy. The use of dual velocity encoding (VENC) or multi-VENC is recommended to avoid velocity wrap around and to increase VNR. In order to maintain sufficient spatio-temporal resolution, a longer imaging time is required, leading to potential patient movement during examination and a corresponding decrease in measurement accuracy.For the clinical application of new technologies, including various acceleration techniques, in vitro and in vivo accuracy verification based on existing accuracy-validated 2D cine PC MRI and 4D flow MRI, as well as accuracy verification on the conservation of mass' principle, should be performed, and intraobserver repeatability, interobserver reproducibility, and test-retest reproducibility should be checked.
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Affiliation(s)
- Haruo Isoda
- Brain and Mind Research Center, Nagoya University, Nagoya, Aichi, Japan
- Biomedical Imaging Sciences, Department of Integrated Health Sciences, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Atsushi Fukuyama
- Faculty of Health Sciences, Department of Radiological Sciences, Japan Healthcare University, Sapporo, Hokkaido, Japan
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Abstract
This special issue of Magnetic Resonance in Medical Sciences features the most recent reviews on 4D Flow MRI. These reviews deal with the current status of the emerging technique of 4D Flow MRI facilitated in various areas that are difficult to obtain with conventional flowmetry. MR signals inherently contain flow velocity information. In previous decades, in vivo blood flow measurement was traditionally performed by 2D methods, such as Doppler ultrasonography and 2D phase-contrast MRI, which have long been regarded as mature techniques in hemodynamic flowmetry. Although 2D velocimetries have many advantages over 4D Flow MRI in terms of cost and accessibility, and provide excellent temporal and in-plane spatial resolutions, they also have some disadvantages. The emerging technology of 4D Flow MRI can overcome the shortcomings of conventional 2D imaging. In recent years, hemodynamic analysis has witnessed significant progress that is primarily attributable to advances in 4D Flow MRI.
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Affiliation(s)
- Yasuo Takehara
- Department of Fundamental Development for Low Invasive Diagnostic Imaging, Nagoya University Graduate School of Medicine
| | - Tetsuro Sekine
- Department of Radiology, Nippon Medical School Musashi Kosugi Hospital
| | - Takayuki Obata
- Applied MRI Research, Department of Molecular Imaging and Theranostics, National Institutes for Quantum Science and Technology
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17
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Dietrich S, Aigner CS, Mayer J, Kolbitsch C, Schulz-Menger J, Schaeffter T, Schmitter S. Motion-compensated fat-water imaging for 3D cardiac MRI at ultra-high fields. Magn Reson Med 2022; 87:2621-2636. [PMID: 35092090 DOI: 10.1002/mrm.29144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 11/23/2021] [Accepted: 12/14/2021] [Indexed: 12/16/2022]
Abstract
PURPOSE Respiratory motion-compensated (MC) 3D cardiac fat-water imaging at 7T. METHODS Free-breathing bipolar 3D triple-echo gradient-recalled-echo (GRE) data with radial phase-encoding (RPE) trajectory were acquired in 11 healthy volunteers (7M\4F, 21-35 years, mean: 30 years) with a wide range of body mass index (BMI; 19.9-34.0 kg/m2 ) and volunteer tailored B 1 + shimming. The bipolar-corrected triple-echo GRE-RPE data were binned into different respiratory phases (self-navigation) and were used for the estimation of non-rigid motion vector fields (MF) and respiratory resolved (RR) maps of the main magnetic field deviations (ΔB0 ). RR ΔB0 maps and MC ΔB0 maps were compared to a reference respiratory phase to assess respiration-induced changes. Subsequently, cardiac binned fat-water images were obtained using a model-based, respiratory motion-corrected image reconstruction. RESULTS The 3D cardiac fat-water imaging at 7T was successfully demonstrated. Local respiration-induced frequency shifts in MC ΔB0 maps are small compared to the chemical shifts used in the multi-peak model. Compared to the reference exhale ΔB0 map these changes are in the order of 10 Hz on average. Cardiac binned MC fat-water reconstruction reduced respiration induced blurring in the fat-water images, and flow artifacts are reduced in the end-diastolic fat-water separated images. CONCLUSION This work demonstrates the feasibility of 3D fat-water imaging at UHF for the entire human heart despite spatial and temporal B 1 + and B0 variations, as well as respiratory and cardiac motion.
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Affiliation(s)
- Sebastian Dietrich
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | | | - Johannes Mayer
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Christoph Kolbitsch
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Jeanette Schulz-Menger
- Experimental and Clinical Research Center, A Joint Cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine and HELIOS Hospital Berlin Buch, Berlin, Germany.,DZHK (German Center for Cardiovascular Research), Partner Site Berlin, Berlin, Germany.,Helios Clinics Berlin-Buch Department of Cardiology and Nephrology, Berlin, Germany
| | - Tobias Schaeffter
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany.,Department of Medical Engineering, Technische Universität Berlin, Germany
| | - Sebastian Schmitter
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany.,Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota, USA
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18
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Celi S, Vignali E, Capellini K, Gasparotti E. On the Role and Effects of Uncertainties in Cardiovascular in silico Analyses. FRONTIERS IN MEDICAL TECHNOLOGY 2022; 3:748908. [PMID: 35047960 PMCID: PMC8757785 DOI: 10.3389/fmedt.2021.748908] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 10/14/2021] [Indexed: 12/13/2022] Open
Abstract
The assessment of cardiovascular hemodynamics with computational techniques is establishing its fundamental contribution within the world of modern clinics. Great research interest was focused on the aortic vessel. The study of aortic flow, pressure, and stresses is at the basis of the understanding of complex pathologies such as aneurysms. Nevertheless, the computational approaches are still affected by sources of errors and uncertainties. These phenomena occur at different levels of the computational analysis, and they also strongly depend on the type of approach adopted. With the current study, the effect of error sources was characterized for an aortic case. In particular, the geometry of a patient-specific aorta structure was segmented at different phases of a cardiac cycle to be adopted in a computational analysis. Different levels of surface smoothing were imposed to define their influence on the numerical results. After this, three different simulation methods were imposed on the same geometry: a rigid wall computational fluid dynamics (CFD), a moving-wall CFD based on radial basis functions (RBF) CFD, and a fluid-structure interaction (FSI) simulation. The differences of the implemented methods were defined in terms of wall shear stress (WSS) analysis. In particular, for all the cases reported, the systolic WSS and the time-averaged WSS (TAWSS) were defined.
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Affiliation(s)
- Simona Celi
- BioCardioLab, UOC Bioingegneria, Fondazione Toscana Gabriele Monasterio, Massa, Italy
| | - Emanuele Vignali
- BioCardioLab, UOC Bioingegneria, Fondazione Toscana Gabriele Monasterio, Massa, Italy
| | - Katia Capellini
- BioCardioLab, UOC Bioingegneria, Fondazione Toscana Gabriele Monasterio, Massa, Italy.,Department of Information Engineering, University of Pisa, Pisa, Italy
| | - Emanuele Gasparotti
- BioCardioLab, UOC Bioingegneria, Fondazione Toscana Gabriele Monasterio, Massa, Italy.,Department of Information Engineering, University of Pisa, Pisa, Italy
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Radbruch A, Paech D, Gassenmaier S, Luetkens J, Isaak A, Herrmann J, Othman A, Schäfer J, Nikolaou K. 1.5 vs 3 Tesla Magnetic Resonance Imaging: A Review of Favorite Clinical Applications for Both Field Strengths-Part 2. Invest Radiol 2021; 56:692-704. [PMID: 34417406 DOI: 10.1097/rli.0000000000000818] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
ABSTRACT The second part of this review deals with experiences in neuroradiological and pediatric examinations using modern magnetic resonance imaging systems with 1.5 T and 3 T, with special attention paid to experiences in pediatric cardiac imaging. In addition, whole-body examinations, which are widely used for diagnostic purposes in systemic diseases, are compared with respect to the image quality obtained in different body parts at both field strengths. A systematic overview of the technical differences at 1.5 T and 3 T has been presented in part 1 of this review, as well as several organ-based magnetic resonance imaging applications including musculoskeletal imaging, abdominal imaging, and prostate diagnostics.
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Affiliation(s)
- Alexander Radbruch
- From the Clinic for Diagnostic and Interventional Neuroradiology, University Hospital Bonn, Bonn
| | - Daniel Paech
- From the Clinic for Diagnostic and Interventional Neuroradiology, University Hospital Bonn, Bonn
| | - Sebastian Gassenmaier
- Department of Radiology, Diagnostic and Interventional Radiology, University of Tübingen, Tübingen
| | - Julian Luetkens
- Clinic for Diagnostic and Interventional Radiology, University Hospital Bonn, Bonn
| | - Alexander Isaak
- Clinic for Diagnostic and Interventional Radiology, University Hospital Bonn, Bonn
| | - Judith Herrmann
- Department of Radiology, Diagnostic and Interventional Radiology, University of Tübingen, Tübingen
| | | | - Jürgen Schäfer
- Department of Radiology, Diagnostic and Interventional Radiology, University of Tübingen, Tübingen
| | - Konstantin Nikolaou
- Department of Radiology, Diagnostic and Interventional Radiology, University of Tübingen, Tübingen
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Abstract
Especially after the launch of 7 T, the ultrahigh magnetic field (UHF) imaging community achieved critically important strides in our understanding of the physics of radiofrequency interactions in the human body, which in turn has led to solutions for the challenges posed by such UHFs. As a result, the originally obtained poor image quality has progressed to the high-quality and high-resolution images obtained at 7 T and now at 10.5 T in the human torso. Despite these tremendous advances, work still remains to further improve the image quality and fully capitalize on the potential advantages UHF has to offer.
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21
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Guo R, Weingärtner S, Šiurytė P, T Stoeck C, Füetterer M, E Campbell-Washburn A, Suinesiaputra A, Jerosch-Herold M, Nezafat R. Emerging Techniques in Cardiac Magnetic Resonance Imaging. J Magn Reson Imaging 2021; 55:1043-1059. [PMID: 34331487 DOI: 10.1002/jmri.27848] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 07/08/2021] [Accepted: 07/09/2021] [Indexed: 11/10/2022] Open
Abstract
Cardiovascular disease is the leading cause of death and a significant contributor of health care costs. Noninvasive imaging plays an essential role in the management of patients with cardiovascular disease. Cardiac magnetic resonance (MR) can noninvasively assess heart and vascular abnormalities, including biventricular structure/function, blood hemodynamics, myocardial tissue composition, microstructure, perfusion, metabolism, coronary microvascular function, and aortic distensibility/stiffness. Its ability to characterize myocardial tissue composition is unique among alternative imaging modalities in cardiovascular disease. Significant growth in cardiac MR utilization, particularly in Europe in the last decade, has laid the necessary clinical groundwork to position cardiac MR as an important imaging modality in the workup of patients with cardiovascular disease. Although lack of availability, limited training, physician hesitation, and reimbursement issues have hampered widespread clinical adoption of cardiac MR in the United States, growing clinical evidence will ultimately overcome these challenges. Advances in cardiac MR techniques, particularly faster image acquisition, quantitative myocardial tissue characterization, and image analysis have been critical to its growth. In this review article, we discuss recent advances in established and emerging cardiac MR techniques that are expected to strengthen its capability in managing patients with cardiovascular disease. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY: Stage 1.
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Affiliation(s)
- Rui Guo
- Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Sebastian Weingärtner
- Department of Imaging Physics, Magnetic Resonance Systems Lab, Delft University of Technology, Delft, The Netherlands
| | - Paulina Šiurytė
- Department of Imaging Physics, Magnetic Resonance Systems Lab, Delft University of Technology, Delft, The Netherlands
| | - Christian T Stoeck
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - Maximilian Füetterer
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - Adrienne E Campbell-Washburn
- Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Avan Suinesiaputra
- Faculty of Engineering and Physical Sciences, University of Leeds, Leeds, UK
| | - Michael Jerosch-Herold
- Department of Radiology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Reza Nezafat
- Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
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22
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On the way to routine cardiac MRI at 7 Tesla - a pilot study on consecutive 84 examinations. PLoS One 2021; 16:e0252797. [PMID: 34297720 PMCID: PMC8301632 DOI: 10.1371/journal.pone.0252797] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 05/23/2021] [Indexed: 11/29/2022] Open
Abstract
Introduction Cardiac magnetic resonance (CMR) at ultrahigh field (UHF) offers the potential of high resolution and fast image acquisition. Both technical and physiological challenges associated with CMR at 7T require specific hardware and pulse sequences. This study aimed to assess the current status and existing, publicly available technology regarding the potential of a clinical application of 7T CMR. Methods Using a 7T MRI scanner and a commercially available radiofrequency coil, a total of 84 CMR examinations on 72 healthy volunteers (32 males, age 19–70 years, weight 50–103 kg) were obtained. Both electrocardiographic and acoustic triggering were employed. The data were analyzed regarding the diagnostic image quality and the influence of patient and hardware dependent factors. 50 complete short axis stacks and 35 four chamber CINE views were used for left ventricular (LV) and right ventricular (RV), mono-planar LV function, and RV fractional area change (FAC). Twenty-seven data sets included aortic flow measurements that were used to calculate stroke volumes. Subjective acceptance was obtained from all volunteers with a standardized questionnaire. Results Functional analysis showed good functions of LV (mean EF 56%), RV (mean EF 59%) and RV FAC (mean FAC 52%). Flow measurements showed congruent results with both ECG and ACT triggering. No significant influence of experimental parameters on the image quality of the LV was detected. Small fractions of 5.4% of LV and 2.5% of RV segments showed a non-diagnostic image quality. The nominal flip angle significantly influenced the RV image quality. Conclusion The results demonstrate that already now a commercially available 7T MRI system, without major methods developments, allows for a solid morphological and functional analysis similar to the clinically established CMR routine approach. This opens the door towards combing routine CMR in patients with development of advanced 7T technology.
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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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Abnormal pulmonary flow is associated with impaired right ventricular coupling in patients with COPD. Int J Cardiovasc Imaging 2021; 37:3039-3048. [PMID: 34021434 DOI: 10.1007/s10554-021-02285-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 05/10/2021] [Indexed: 01/31/2023]
Abstract
Cor Pulmonale or right ventricular (RV) dysfunction due to pulmonary disease is an expected complication of COPD resulting primarily from increased afterload mediated by chronic alveolar hypoxemia and resulting hypoxic pulmonary vasoconstriction. Early detection of elevated RV afterload has been previously demonstrated by visualization of abnormal flow patterns in the proximal pulmonary arteries. Prior analysis of helicity in the pulmonary arteries in pulmonary hypertension patients has demonstrated a strong association between helicity and increased RV afterload. However, these flow hemodynamics have yet to be fully explored in patients with COPD. We hypothesized that patients with COPD will have abnormal pulmonary flow as evaluated by 4D-Flow MRI and associated with RV function and pulmonary arterial stiffness. Patients with COPD (n = 15) (65 years ± 6) and controls (n = 10) (58 years ± 9) underwent 4D-Flow MRI to calculate helicity. The helicity was calculated in the main pulmonary artery (MPA) and along the RV outflow tract (RVOT)-MPA axis. Main pulmonary arterial stiffness was measured using the relative area change (RAC). We found COPD patients had decreased helicity relative to healthy controls in the MPA (19.4 ± 7.8vs 32.8 ± 15.9, P = 0.007) and reduced helicity along the RVOT-MPA axis (33.2 ± 9.0 vs 43.5 ± 8.3, P = 0.010). Our investigation indicates a strong association between helicity along the MPA-RV outflow tract axis and RV function and suggests that 4D-Flow MRI might be a sensitive tool in evaluating RV-pulmonary arterial coupling in COPD.
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Dietrich S, Aigner CS, Kolbitsch C, Mayer J, Ludwig J, Schmidt S, Schaeffter T, Schmitter S. 3D Free-breathing multichannel absolute B 1 + Mapping in the human body at 7T. Magn Reson Med 2020; 85:2552-2567. [PMID: 33283915 DOI: 10.1002/mrm.28602] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 10/23/2020] [Accepted: 10/25/2020] [Indexed: 12/13/2022]
Abstract
PURPOSE To introduce and investigate a method for free-breathing three-dimensional (3D) B 1 + mapping of the human body at ultrahigh field (UHF), which can be used to generate homogenous flip angle (FA) distributions in the human body at UHF. METHODS A 3D relative B 1 + mapping sequence with a radial phase-encoding (RPE) k-space trajectory was developed and applied in 11 healthy subjects at 7T. An RPE-based actual flip angle mapping method was applied with a dedicated B 1 + shim setting to calibrate the relative B 1 + maps yielding absolute B 1 + maps of the individual transmit channels. The method was evaluated in a motion phantom and by multidimensional in vivo measurements. Additionally, 3D gradient echo scans with and without static phase-only B 1 + shims were used to qualitatively validate B 1 + shim predictions. RESULTS The phantom validation revealed good agreement for B 1 + maps between dynamic measurement and static reference acquisition. The proposed 3D method was successfully validated in vivo by comparing magnitude and phase distributions with a 2D Cartesian reference. 3D B 1 + maps free from visible motion artifacts were successfully acquired for 11 subjects with body mass indexes ranging from 19 kg/m2 to 34 kg/m2 . 3D respiration-resolved absolute B 1 + maps indicated FA differences between inhalation and exhalation up to 15% for one channel and up to 24% for combined channels for shallow breathing. CONCLUSION The proposed method provides respiration-resolved absolute 3D B 1 + maps of the human body at UHF, which enables the investigation and development of 3D B 1 + shimming and parallel transmission methods to further enhance body imaging at UHF.
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Affiliation(s)
- Sebastian Dietrich
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Christoph S Aigner
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Christoph Kolbitsch
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Johannes Mayer
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Juliane Ludwig
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Simon Schmidt
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Tobias Schaeffter
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
- Department of Medical Engineering, Technische Universität Berlin, Berlin, Germany
| | - Sebastian Schmitter
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota, USA
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26
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Ibrahim ESH, Arpinar VE, Muftuler LT, Stojanovska J, Nencka AS, Koch KM. Cardiac functional magnetic resonance imaging at 7T: Image quality optimization and ultra-high field capabilities. World J Radiol 2020; 12:231-246. [PMID: 33240463 PMCID: PMC7653183 DOI: 10.4329/wjr.v12.i10.231] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 09/27/2020] [Accepted: 10/14/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND 7T cardiac magnetic resonance imaging (MRI) introduces several advantages, as well as some limitations, compared to lower-field imaging. The capabilities of ultra-high field (UHF) MRI have not been fully exploited in cardiac functional imaging.
AIM To optimize 7T cardiac MRI functional imaging without the need for conducting B1 shimming or subject-specific tuning, which improves scan efficiency. In this study, we provide results from phantom and in vivo scans using a multi-channel transceiver modular coil.
METHODS We investigated the effects of adding a dielectric pad at different locations next to the imaged region of interest on improving image quality in subjects with different body habitus. We also investigated the effects of adjusting the imaging flip angle in cine and tagging sequences on improving image quality, B1 field homogeneity, signal-to-noise ratio (SNR), blood-myocardium contrast-to-noise ratio (CNR), and tagging persistence throughout the cardiac cycle.
RESULTS The results showed the capability of achieving improved image quality with high spatial resolution (0.75 mm × 0.75 mm × 2 mm), high temporal resolution (20 ms), and increased tagging persistence (for up to 1200 ms cardiac cycle duration) at 7T cardiac MRI after adjusting scan set-up and imaging parameters. Adjusting the imaging flip angle was essential for achieving optimal SNR and myocardium-to-blood CNR. Placing a dielectric pad at the anterior left position of the chest resulted in improved B1 homogeneity compared to other positions, especially in subjects with small chest size.
CONCLUSION Improved regional and global cardiac functional imaging can be achieved at 7T MRI through simple scan set-up adjustment and imaging parameter optimization, which would allow for more streamlined and efficient UHF cardiac MRI.
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Affiliation(s)
- El-Sayed H Ibrahim
- Department of Radiology, Medical College of Wisconsin, Milwaukee, WI 53226, United States
| | - V Emre Arpinar
- Department of Radiology, Medical College of Wisconsin, Milwaukee, WI 53226, United States
| | - L Tugan Muftuler
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI 53226, United States
| | - Jadranka Stojanovska
- Department of Radiology, University of Michigan, Ann Arbor, MI 48109, United States
| | - Andrew S Nencka
- Department of Radiology, Medical College of Wisconsin, Milwaukee, WI 53226, United States
| | - Kevin M Koch
- Department of Radiology, Medical College of Wisconsin, Milwaukee, WI 53226, United States
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Ibrahim ESH, Arpinar VE, Muftuler LT, Stojanovska J, Nencka AS, Koch KM. Cardiac functional magnetic resonance imaging at 7T: Image quality optimization and ultra-high field capabilities. World J Radiol 2020. [DOI: 10.4329/wjr.v12.i10.229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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28
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Levilly S, Castagna M, Idier J, Bonnefoy F, Le Touzé D, Moussaoui S, Paul-Gilloteaux P, Serfaty JM. Towards quantitative evaluation of wall shear stress from 4D flow imaging. Magn Reson Imaging 2020; 74:232-243. [PMID: 32889090 DOI: 10.1016/j.mri.2020.08.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 06/12/2020] [Accepted: 08/23/2020] [Indexed: 11/25/2022]
Abstract
Wall shear stress (WSS) is a relevant hemodynamic indicator of the local stress applied on the endothelium surface. More specifically, its spatiotemporal distribution reveals crucial in the evolution of many pathologies such as aneurysm, stenosis, and atherosclerosis. This paper introduces a new solution, called PaLMA, to quantify the WSS from 4D Flow MRI data. It relies on a two-step local parametric model, to accurately describe the vessel wall and the velocity-vector field in the neighborhood of a given point of interest. Extensive validations have been performed on synthetic 4D Flow MRI data, including four datasets generated from patient specific computational fluid dynamics simulations on carotids. The validation tests are focused on the impact of the noise component, of the resolution level, and of the segmentation accuracy concerning the vessel position in the context of complex flow patterns. In simulated cases aimed to reproduce clinical acquisition conditions, the WSS quantification performance reached by PaLMA is significantly higher (with a gain in RMSE of 12 to 27%) than the reference one obtained using the smoothing B-spline method proposed by Potters et al. (2015) method, while the computation time is equivalent for both WSS quantification methods.
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Affiliation(s)
- Sébastien Levilly
- Laboratoire des Sciences du Numérique de Nantes (ECN and CNRS), 1 rue de la Noë, BP 92101, 44321 Nantes Cedex 3, France.
| | - Marco Castagna
- Ecole Centrale de Nantes, LHEEA Lab (ECN and CNRS), 1 rue de la Noë, 44300 Nantes, France; Université de Nantes, CHU Nantes, CNRS UMR 6291, INSERM UMR 1087, L'institut du thorax, F-44000 Nantes, France
| | - Jérôme Idier
- Laboratoire des Sciences du Numérique de Nantes (ECN and CNRS), 1 rue de la Noë, BP 92101, 44321 Nantes Cedex 3, France
| | - Félicien Bonnefoy
- Ecole Centrale de Nantes, LHEEA Lab (ECN and CNRS), 1 rue de la Noë, 44300 Nantes, France
| | - David Le Touzé
- Ecole Centrale de Nantes, LHEEA Lab (ECN and CNRS), 1 rue de la Noë, 44300 Nantes, France
| | - Saïd Moussaoui
- Laboratoire des Sciences du Numérique de Nantes (ECN and CNRS), 1 rue de la Noë, BP 92101, 44321 Nantes Cedex 3, France
| | - Perrine Paul-Gilloteaux
- Université de Nantes, CHU Nantes, CNRS UMR 6291, INSERM UMR 1087, L'institut du thorax, F-44000 Nantes, France; Université de Nantes, CHU Nantes, Inserm, CNRS, SFR Santé, Inserm UMS 016, CNRS UMS 3556, F-44000 Nantes, France
| | - Jean-Michel Serfaty
- Université de Nantes, CHU Nantes, CNRS UMR 6291, INSERM UMR 1087, L'institut du thorax, F-44000 Nantes, France
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Wiesemann S, Schmitter S, Demir A, Prothmann M, Schwenke C, Chawla A, von Knobelsdorff-Brenkenhoff F, Greiser A, Jin N, Bollache E, Markl M, Schulz-Menger J. Impact of sequence type and field strength (1.5, 3, and 7T) on 4D flow MRI hemodynamic aortic parameters in healthy volunteers. Magn Reson Med 2020; 85:721-733. [PMID: 32754969 DOI: 10.1002/mrm.28450] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 06/22/2020] [Accepted: 07/08/2020] [Indexed: 01/15/2023]
Abstract
PURPOSE 4D flow magnetic resonance imaging (4D-MRI) allows time-resolved visualization of blood flow patterns, quantification of volumes, velocities, and advanced parameters, such as wall shear stress (WSS). As 4D-MRI enters the clinical arena, standardization and awareness of confounders are important. Our aim was to evaluate the equivalence of 4D flow-derived aortic hemodynamics in healthy volunteers using different sequences and field strengths. METHODS 4D-MRI was acquired in 10 healthy volunteers at 1.5T using three different prototype sequences, at 3T and at 7T (Siemens Healthineers). After evaluation of diagnostic quality in three segments (ascending-, descending aorta, aortic arch), peak velocity, flow volumes, and WSS were investigated. Equivalence limits for comparison of field strengths/sequences were based on the limits of Bland-Altman analyses of the intraobserver variability. RESULTS Non-diagnostic quality was found in 10/144 segments, 9/10 were obtained at 7T. Apart for the comparison of forward flow between sequence 1 and 3, the differences in measurements between field strengths/sequences exceeded the range of agreement. Significant differences were found between field strengths/sequences for forward flow (1.5T vs. 3T, 3T vs. 7T, sequence 1 vs. 3, 2 vs. 3 [P < .001]), WSS (1.5T vs. 3T [P < .05], sequence 1 vs. 2, 1 vs. 3, 2 vs. 3 [P < .001]), and peak velocity (1.5T vs. 7T, sequence 1 vs. 3 [P > .001]). All parameters at all field strengths/with all sequences correlated moderately to strongly (r ≥ 0.5). CONCLUSION Data from all sequences could be acquired and resulting images showed sufficient quality for further analysis. However, the variability of the measurements of peak velocity, flow volumes, and WSS was higher when comparing field strengths/sequences as the equivalence limits defined by the intraobserver assessments.
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Affiliation(s)
- Stephanie Wiesemann
- Department of Cardiology and Nephrology, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine and HELIOS Hospital Berlin Buch, Berlin, Germany.,DZHK (German Center for Cardiovascular Research), partner site Berlin, Berlin, Germany
| | - Sebastian Schmitter
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Aylin Demir
- Department of Cardiology and Nephrology, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine and HELIOS Hospital Berlin Buch, Berlin, Germany
| | - Marcel Prothmann
- Department of Cardiology and Nephrology, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine and HELIOS Hospital Berlin Buch, Berlin, Germany
| | | | - Ashish Chawla
- Khoo Teck Puat Hospital, Yishun Central, Singapore, Singapore
| | - Florian von Knobelsdorff-Brenkenhoff
- Department of Cardiology and Nephrology, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine and HELIOS Hospital Berlin Buch, Berlin, Germany.,Clinic Agatharied, Department of Cardiology, Ludwig-Maximilians-University Munich, Hausham, Germany
| | | | - Ning Jin
- Siemens Medical Solutions, Columbus, Ohio, USA
| | - Emilie Bollache
- Sorbonne Université, CNRS, INSERM, Laboratoire d'Imagerie Biomédicale, LIB, Paris, France
| | - Michael Markl
- Department of Radiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA
| | - Jeanette Schulz-Menger
- Department of Cardiology and Nephrology, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine and HELIOS Hospital Berlin Buch, Berlin, Germany.,DZHK (German Center for Cardiovascular Research), partner site Berlin, Berlin, Germany
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30
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Schmitter S, Adriany G, Waks M, Moeller S, Aristova M, Vali A, Auerbach EJ, Van de Moortele PF, Ugurbil K, Schnell S. Bilateral Multiband 4D Flow MRI of the Carotid Arteries at 7T. Magn Reson Med 2020; 84:1947-1960. [PMID: 32187742 DOI: 10.1002/mrm.28256] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 01/31/2020] [Accepted: 02/24/2020] [Indexed: 12/26/2022]
Abstract
PURPOSE Simultaneous multislab (SMSb) 4D flow MRI was developed and implemented at 7T for accelerated acquisition of the 3D blood velocity vector field in both carotid bifurcations. METHODS SMSb was applied to 4D flow to acquire blood velocities in both carotid bifurcations in sagittal orientation using a local transmit/receive coil at 7T. B 1 + transmit efficiency was optimized by B 1 + shimming. SMSb 4D flow was obtained in 8 healthy subjects in single-band (SB) and multiband (MB) fashion. Additionally, MB data were retrospectively undersampled to simulate GRAPPA R = 2 (MB2_GRAPPA2), and both SB datasets were added to form an artificial MB dataset (SumSB). The band separation performance was quantified by signal leakage. Peak velocity and total flow values were calculated and compared to SB via intraclass correlation analysis (ICC). RESULTS Clean slab separation was achieved yielding a mean signal leakage of 13% above the mean SB noise level. Mean total flow for MB2, SumSB, and MB_GRAPPA2 deviated less than 9% from the SB values. Peak velocities averaged over all vessels and subjects were 0.48 ± 0.11 m/s for SB, 0.47 ± 0.12 m/s for SumSB, 0.50 ± 0.13 m/s for MB2, and 0.53 ± 0.13 m/s for MB2_GRAPPA2. ICC revealed excellent absolute agreement and consistency of total flow for all methods compared to SB2. Peak velocity showed good to excellent agreement and consistency for SumSB and MB2 and MB2_GRAPPA2 method showed poor to excellent agreement and good to excellent consistency. CONCLUSION Simultaneous multislab 4D Flow MRI allows accurate quantification of total flow and peak velocity while reducing scan times.
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Affiliation(s)
- Sebastian Schmitter
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA.,Physikalisch-Technische Bundesanstalt, Braunschweig and Berlin, Germany
| | - Gregor Adriany
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
| | - Matt Waks
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
| | - Steen Moeller
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
| | - Maria Aristova
- McCormick School of Engineering, Northwestern University, Evanston, USA.,Feinberg School of Medicine, Northwestern University, Chicago, USA
| | - Alireza Vali
- Feinberg School of Medicine, Northwestern University, Chicago, USA
| | - Edward J Auerbach
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
| | | | - Kamil Ugurbil
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
| | - Susanne Schnell
- Feinberg School of Medicine, Northwestern University, Chicago, USA
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Velocity encoding and velocity compensation for multi-spoke RF excitation. Magn Reson Imaging 2020; 66:69-85. [DOI: 10.1016/j.mri.2019.11.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 10/24/2019] [Accepted: 11/03/2019] [Indexed: 11/22/2022]
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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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Neuhaus E, Weiss K, Bastkowski R, Koopmann J, Maintz D, Giese D. Accelerated aortic 4D flow cardiovascular magnetic resonance using compressed sensing: applicability, validation and clinical integration. J Cardiovasc Magn Reson 2019; 21:65. [PMID: 31638997 PMCID: PMC6802342 DOI: 10.1186/s12968-019-0573-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 08/29/2019] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Three-dimensional time-resolved phase-contrast cardiovascular magnetic resonance (4D flow CMR) enables the quantification and visualisation of blood flow, but its clinical applicability remains hampered by its long scan time. The aim of this study was to evaluate the use of compressed sensing (CS) with on-line reconstruction to accelerate the acquisition and reconstruction of 4D flow CMR of the thoracic aorta. METHODS 4D flow CMR of the thoracic aorta was acquired in 20 healthy subjects using CS with acceleration factors ranging from 4 to 10. As a reference, conventional parallel imaging (SENSE) with acceleration factor 2 was used. Flow curves, net flows, peak flows and peak velocities were extracted from six contours along the aorta. To measure internal data consistency, a quantitative particle trace analysis was performed. Additionally, scan-rescan, inter- and intraobserver reproducibility were assessed. Subsequently, 4D flow CMR with CS factor 6 was acquired in 3 patients with differing aortopathies. The flow patterns resulting from particle trace visualisation were qualitatively analysed. RESULTS All collected data were successfully acquired and reconstructed on-line. The average acquisition time including respiratory navigator efficiency with CS factor 6 was 5:02 ± 2:23 min while reconstruction took approximately 9 min. For CS factors of 8 or less, mean differences in net flow, peak flow and peak velocity as compared to SENSE were below 2.2 ± 7.8 ml/cycle, 4.6 ± 25.2 ml/s and - 7.9 ± 13.0 cm/s, respectively. For a CS factor of 10 differences reached 5.4 ± 8.0 ml/cycle, 14.4 ± 28.3 ml/s and - 4.0 ± 12.2 cm/s. Scan-rescan analysis yielded mean differences in net flow of - 0.7 ± 4.9 ml/cycle for SENSE and - 0.2 ± 8.5 ml/cycle for CS factor of 6. CONCLUSIONS A six- to eightfold acceleration of 4D flow CMR using CS is feasible. Up to a CS acceleration rate of 6, no statistically significant differences in measured flow parameters could be observed with respect to the reference technique. Acquisitions in patients with aortopathies confirm the potential to integrate the proposed method in a clinical routine setting, whereby its main benefits are scan-time savings and direct on-line reconstruction.
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Affiliation(s)
- Elisabeth Neuhaus
- Institute for Diagnostic and Interventional Radiology, University of Cologne, Faculty of Medicine and University Hospital of Cologne, Kerpener Str. 62, 50937 Cologne, Germany
| | - Kilian Weiss
- Institute for Diagnostic and Interventional Radiology, University of Cologne, Faculty of Medicine and University Hospital of Cologne, Kerpener Str. 62, 50937 Cologne, Germany
- Philips GmbH, Hamburg, Germany
| | - Rene Bastkowski
- Institute for Diagnostic and Interventional Radiology, University of Cologne, Faculty of Medicine and University Hospital of Cologne, Kerpener Str. 62, 50937 Cologne, Germany
| | - Jonas Koopmann
- Institute for Diagnostic and Interventional Radiology, University of Cologne, Faculty of Medicine and University Hospital of Cologne, Kerpener Str. 62, 50937 Cologne, Germany
| | - David Maintz
- Institute for Diagnostic and Interventional Radiology, University of Cologne, Faculty of Medicine and University Hospital of Cologne, Kerpener Str. 62, 50937 Cologne, Germany
| | - Daniel Giese
- Institute for Diagnostic and Interventional Radiology, University of Cologne, Faculty of Medicine and University Hospital of Cologne, Kerpener Str. 62, 50937 Cologne, Germany
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Erturk MA, Li X, Van de Moortele PF, Ugurbil K, Metzger GJ. Evolution of UHF Body Imaging in the Human Torso at 7T: Technology, Applications, and Future Directions. Top Magn Reson Imaging 2019; 28:101-124. [PMID: 31188271 PMCID: PMC6587233 DOI: 10.1097/rmr.0000000000000202] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2023]
Abstract
The potential value of ultrahigh field (UHF) magnetic resonance imaging (MRI) and spectroscopy to biomedical research and in clinical applications drives the development of technologies to overcome its many challenges. The increased difficulties of imaging the human torso compared with the head include its overall size, the dimensions and location of its anatomic targets, the increased prevalence and magnitude of physiologic effects, the limited availability of tailored RF coils, and the necessary transmit chain hardware. Tackling these issues involves addressing notoriously inhomogeneous transmit B1 (B1) fields, limitations in peak B1, larger spatial variations of the static magnetic field B0, and patient safety issues related to implants and local RF power deposition. However, as research institutions and vendors continue to innovate, the potential gains are beginning to be realized. Solutions overcoming the unique challenges associated with imaging the human torso are reviewed as are current studies capitalizing on the benefits of UHF in several anatomies and applications. As the field progresses, strategies associated with the RF system architecture, calibration methods, RF pulse optimization, and power monitoring need to be further integrated into the MRI systems making what are currently complex processes more streamlined. Meanwhile, the UHF MRI community must seize the opportunity to build upon what have been so far proof of principle and feasibility studies and begin to further explore the true impact in both research and the clinic.
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Affiliation(s)
- M Arcan Erturk
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN
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Niendorf T, Schulz-Menger J, Paul K, Huelnhagen T, Ferrari VA, Hodge R. High Field Cardiac Magnetic Resonance Imaging: A Case for Ultrahigh Field Cardiac Magnetic Resonance. Circ Cardiovasc Imaging 2019; 10:CIRCIMAGING.116.005460. [PMID: 28611118 DOI: 10.1161/circimaging.116.005460] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Thoralf Niendorf
- From the Berlin Ultrahigh Field Facility, Max-Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (T.N., K.P., T.H., R.H.); DZHK (German Centre for Cardiovascular Research), partner site Berlin (T.N., J.S.-M.); Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (J.S.-M.); Department for Cardiology and Nephrology, HELIOS Clinic Berlin-Buch, Germany (J.S.-M.); and Division of Cardiovascular Medicine and Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia (V.A.F.).
| | - Jeanette Schulz-Menger
- From the Berlin Ultrahigh Field Facility, Max-Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (T.N., K.P., T.H., R.H.); DZHK (German Centre for Cardiovascular Research), partner site Berlin (T.N., J.S.-M.); Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (J.S.-M.); Department for Cardiology and Nephrology, HELIOS Clinic Berlin-Buch, Germany (J.S.-M.); and Division of Cardiovascular Medicine and Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia (V.A.F.)
| | - Katharina Paul
- From the Berlin Ultrahigh Field Facility, Max-Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (T.N., K.P., T.H., R.H.); DZHK (German Centre for Cardiovascular Research), partner site Berlin (T.N., J.S.-M.); Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (J.S.-M.); Department for Cardiology and Nephrology, HELIOS Clinic Berlin-Buch, Germany (J.S.-M.); and Division of Cardiovascular Medicine and Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia (V.A.F.)
| | - Till Huelnhagen
- From the Berlin Ultrahigh Field Facility, Max-Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (T.N., K.P., T.H., R.H.); DZHK (German Centre for Cardiovascular Research), partner site Berlin (T.N., J.S.-M.); Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (J.S.-M.); Department for Cardiology and Nephrology, HELIOS Clinic Berlin-Buch, Germany (J.S.-M.); and Division of Cardiovascular Medicine and Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia (V.A.F.)
| | - Victor A Ferrari
- From the Berlin Ultrahigh Field Facility, Max-Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (T.N., K.P., T.H., R.H.); DZHK (German Centre for Cardiovascular Research), partner site Berlin (T.N., J.S.-M.); Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (J.S.-M.); Department for Cardiology and Nephrology, HELIOS Clinic Berlin-Buch, Germany (J.S.-M.); and Division of Cardiovascular Medicine and Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia (V.A.F.)
| | - Russell Hodge
- From the Berlin Ultrahigh Field Facility, Max-Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (T.N., K.P., T.H., R.H.); DZHK (German Centre for Cardiovascular Research), partner site Berlin (T.N., J.S.-M.); Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany (J.S.-M.); Department for Cardiology and Nephrology, HELIOS Clinic Berlin-Buch, Germany (J.S.-M.); and Division of Cardiovascular Medicine and Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia (V.A.F.)
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Ladd ME, Bachert P, Meyerspeer M, Moser E, Nagel AM, Norris DG, Schmitter S, Speck O, Straub S, Zaiss M. Pros and cons of ultra-high-field MRI/MRS for human application. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2018; 109:1-50. [PMID: 30527132 DOI: 10.1016/j.pnmrs.2018.06.001] [Citation(s) in RCA: 250] [Impact Index Per Article: 41.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 06/06/2018] [Accepted: 06/07/2018] [Indexed: 05/08/2023]
Abstract
Magnetic resonance imaging and spectroscopic techniques are widely used in humans both for clinical diagnostic applications and in basic research areas such as cognitive neuroimaging. In recent years, new human MR systems have become available operating at static magnetic fields of 7 T or higher (≥300 MHz proton frequency). Imaging human-sized objects at such high frequencies presents several challenges including non-uniform radiofrequency fields, enhanced susceptibility artifacts, and higher radiofrequency energy deposition in the tissue. On the other side of the scale are gains in signal-to-noise or contrast-to-noise ratio that allow finer structures to be visualized and smaller physiological effects to be detected. This review presents an overview of some of the latest methodological developments in human ultra-high field MRI/MRS as well as associated clinical and scientific applications. Emphasis is given to techniques that particularly benefit from the changing physical characteristics at high magnetic fields, including susceptibility-weighted imaging and phase-contrast techniques, imaging with X-nuclei, MR spectroscopy, CEST imaging, as well as functional MRI. In addition, more general methodological developments such as parallel transmission and motion correction will be discussed that are required to leverage the full potential of higher magnetic fields, and an overview of relevant physiological considerations of human high magnetic field exposure is provided.
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Affiliation(s)
- Mark E Ladd
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Medicine, University of Heidelberg, Heidelberg, Germany; Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany; Erwin L. Hahn Institute for MRI, University of Duisburg-Essen, Essen, Germany.
| | - Peter Bachert
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany.
| | - Martin Meyerspeer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria; MR Center of Excellence, Medical University of Vienna, Vienna, Austria.
| | - Ewald Moser
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria; MR Center of Excellence, Medical University of Vienna, Vienna, Austria.
| | - Armin M Nagel
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
| | - David G Norris
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, Netherlands; Erwin L. Hahn Institute for MRI, University of Duisburg-Essen, Essen, Germany.
| | - Sebastian Schmitter
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany.
| | - Oliver Speck
- Department of Biomedical Magnetic Resonance, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany; German Center for Neurodegenerative Diseases, Magdeburg, Germany; Center for Behavioural Brain Sciences, Magdeburg, Germany; Leibniz Institute for Neurobiology, Magdeburg, Germany.
| | - Sina Straub
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - Moritz Zaiss
- High-Field Magnetic Resonance Center, Max-Planck-Institute for Biological Cybernetics, Tübingen, Germany.
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Markenroth Bloch K, Töger J, Ståhlberg F. Investigation of cerebrospinal fluid flow in the cerebral aqueduct using high-resolution phase contrast measurements at 7T MRI. Acta Radiol 2018; 59:988-996. [PMID: 29141450 DOI: 10.1177/0284185117740762] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Background The cerebral aqueduct is a central conduit for cerebrospinal fluid (CSF), and non-invasive quantification of CSF flow in the aqueduct may be an important tool for diagnosis and follow-up of treatment. Magnetic resonance (MR) methods at clinical field strengths are limited by low spatial resolution. Purpose To investigate the feasibility of high-resolution through-plane MR flow measurements (2D-PC) in the cerebral aqueduct at high field strength (7T). Material and Methods 2D-PC measurements in the aqueduct were performed in nine healthy individuals at 7T. Measurement accuracy was determined using a phantom. Aqueduct area, mean velocity, maximum velocity, minimum velocity, net flow, and mean flow were determined using in-plane resolutions 0.8 × 0.8, 0.5 × 0.5, 0.3 × 0.3, and 0.2 × 0.2 mm2. Feasibility criteria were defined based on scan time and spatial and temporal resolution. Results Phantom validation of 2D-PC MR showed good accuracy. In vivo, stroke volume was -8.2 ± 4.4, -4.7 ± 2.8, -6.0 ± 3.8, and -3.7 ± 2.1 µL for 0.8 × 0.8, 0.5 × 0.5, 0.3 × 0.3, and 0.2 × 0.2 mm2, respectively. The scan with 0.3 × 0.3 mm2 resolution fulfilled the feasibility criteria for a wide range of heart rates and aqueduct diameters. Conclusion 7T MR enables non-invasive quantification of CSF flow and velocity in the cerebral aqueduct with high spatial resolution.
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Affiliation(s)
| | - Johannes Töger
- Department of Diagnostic Radiology, Lund University, Skåne University Hospital, Lund, Sweden
| | - Freddy Ståhlberg
- Department of Diagnostic Radiology, Lund University, Skåne University Hospital, Lund, Sweden
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
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Liu J, Koskas L, Faraji F, Kao E, Wang Y, Haraldsson H, Kefayati S, Zhu C, Ahn S, Laub G, Saloner D. Highly accelerated intracranial 4D flow MRI: evaluation of healthy volunteers and patients with intracranial aneurysms. MAGMA (NEW YORK, N.Y.) 2018; 31:295-307. [PMID: 28785850 PMCID: PMC5803461 DOI: 10.1007/s10334-017-0646-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 07/27/2017] [Accepted: 07/28/2017] [Indexed: 02/01/2023]
Abstract
OBJECTIVES To evaluate an accelerated 4D flow MRI method that provides high temporal resolution in a clinically feasible acquisition time for intracranial velocity imaging. MATERIALS AND METHODS Accelerated 4D flow MRI was developed by using a pseudo-random variable-density Cartesian undersampling strategy (CIRCUS) with the combination of k-t, parallel imaging and compressed sensing image reconstruction techniques (k-t SPARSE-SENSE). Four-dimensional flow data were acquired on five healthy volunteers and eight patients with intracranial aneurysms using CIRCUS (acceleration factor of R = 4, termed CIRCUS4) and GRAPPA (R = 2, termed GRAPPA2) as the reference method. Images with three times higher temporal resolution (R = 12, CIRCUS12) were also reconstructed from the same acquisition as CIRCUS4. Qualitative and quantitative image assessment was performed on the images acquired with different methods, and complex flow patterns in the aneurysms were identified and compared. RESULTS Four-dimensional flow MRI with CIRCUS was achieved in 5 min and allowed further improved temporal resolution of <30 ms. Volunteer studies showed similar qualitative and quantitative evaluation obtained with the proposed approach compared to the reference (overall image scores: GRAPPA2 3.2 ± 0.6; CIRCUS4 3.1 ± 0.7; CIRCUS12 3.3 ± 0.4; difference of the peak velocities: -3.83 ± 7.72 cm/s between CIRCUS4 and GRAPPA2, -1.72 ± 8.41 cm/s between CIRCUS12 and GRAPPA2). In patients with intracranial aneurysms, the higher temporal resolution improved capturing of the flow features in intracranial aneurysms (pathline visualization scores: GRAPPA2 2.2 ± 0.2; CIRCUS4 2.5 ± 0.5; CIRCUS12 2.7 ± 0.6). CONCLUSION The proposed rapid 4D flow MRI with a high temporal resolution is a promising tool for evaluating intracranial aneurysms in a clinically feasible acquisition time.
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Affiliation(s)
- Jing Liu
- Radiology and Biomedical Imaging, University of California San Francisco, 185 Berry St, Suite 350, San Francisco, CA, 94107, USA.
| | - Louise Koskas
- Radiology and Biomedical Imaging, University of California San Francisco, 185 Berry St, Suite 350, San Francisco, CA, 94107, USA
| | - Farshid Faraji
- Radiology and Biomedical Imaging, University of California San Francisco, 185 Berry St, Suite 350, San Francisco, CA, 94107, USA
| | - Evan Kao
- Radiology and Biomedical Imaging, University of California San Francisco, 185 Berry St, Suite 350, San Francisco, CA, 94107, USA
| | - Yan Wang
- Radiology and Biomedical Imaging, University of California San Francisco, 185 Berry St, Suite 350, San Francisco, CA, 94107, USA
| | - Henrik Haraldsson
- Radiology and Biomedical Imaging, University of California San Francisco, 185 Berry St, Suite 350, San Francisco, CA, 94107, USA
| | - Sarah Kefayati
- Radiology and Biomedical Imaging, University of California San Francisco, 185 Berry St, Suite 350, San Francisco, CA, 94107, USA
| | - Chengcheng Zhu
- Radiology and Biomedical Imaging, University of California San Francisco, 185 Berry St, Suite 350, San Francisco, CA, 94107, USA
| | | | | | - David Saloner
- Radiology and Biomedical Imaging, University of California San Francisco, 185 Berry St, Suite 350, San Francisco, CA, 94107, USA
- Radiology Service, VA Medical Center, San Francisco, CA, USA
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Advances in MR angiography with 7T MRI: From microvascular imaging to functional angiography. Neuroimage 2018; 168:269-278. [DOI: 10.1016/j.neuroimage.2017.01.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 01/03/2017] [Accepted: 01/09/2017] [Indexed: 01/15/2023] Open
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Experimental quantification of the fluid dynamics in blood-processing devices through 4D-flow imaging: A pilot study on a real oxygenator/heat-exchanger module. J Biomech 2018; 68:14-23. [PMID: 29279196 DOI: 10.1016/j.jbiomech.2017.12.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 11/03/2017] [Accepted: 12/07/2017] [Indexed: 11/21/2022]
Abstract
The performance of blood-processing devices largely depends on the associated fluid dynamics, which hence represents a key aspect in their design and optimization. To this aim, two approaches are currently adopted: computational fluid-dynamics, which yields highly resolved three-dimensional data but relies on simplifying assumptions, and in vitro experiments, which typically involve the direct video-acquisition of the flow field and provide 2D data only. We propose a novel method that exploits space- and time-resolved magnetic resonance imaging (4D-flow) to quantify the complex 3D flow field in blood-processing devices and to overcome these limitations. We tested our method on a real device that integrates an oxygenator and a heat exchanger. A dedicated mock loop was implemented, and novel 4D-flow sequences with sub-millimetric spatial resolution and region-dependent velocity encodings were defined. Automated in house software was developed to quantify the complex 3D flow field within the different regions of the device: region-dependent flow rates, pressure drops, paths of the working fluid and wall shear stresses were computed. Our analysis highlighted the effects of fine geometrical features of the device on the local fluid-dynamics, which would be unlikely observed by current in vitro approaches. Also, the effects of non-idealities on the flow field distribution were captured, thanks to the absence of the simplifying assumptions that typically characterize numerical models. To the best of our knowledge, our approach is the first of its kind and could be extended to the analysis of a broad range of clinically relevant devices.
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Schäfer M, Barker AJ, Kheyfets V, Stenmark KR, Crapo J, Yeager ME, Truong U, Buckner JK, Fenster BE, Hunter KS. Helicity and Vorticity of Pulmonary Arterial Flow in Patients With Pulmonary Hypertension: Quantitative Analysis of Flow Formations. J Am Heart Assoc 2017; 6:JAHA.117.007010. [PMID: 29263034 PMCID: PMC5779020 DOI: 10.1161/jaha.117.007010] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Background Qualitative and quantitative flow hemodynamic indexes have been shown to reflect right ventricular (RV) afterload and function in pulmonary hypertension (PH). We aimed to quantify flow hemodynamic formations in pulmonary arteries using 4‐dimensional flow cardiac magnetic resonance imaging and the spatial velocity derivatives helicity and vorticity in a heterogeneous PH population. Methods and Results Patients with PH (n=35) and controls (n=10) underwent 4‐dimensional flow magnetic resonance imaging study for computation of helicity and vorticity in the main pulmonary artery (MPA), the right pulmonary artery, and the RV outflow tract. Helicity and vorticity were correlated with standard RV volumetric and functional indexes along with MPA stiffness assessed by measuring relative area change. Patients with PH had a significantly decreased helicity in the MPA (8 versus 32 m/s2; P<0.001), the right pulmonary artery (24 versus 50 m/s2; P<0.001), and the RV outflow tract–MPA unit (15 versus 42 m/s2; P<0.001). Vorticity was significantly decreased in patients with PH only in the right pulmonary artery (26 versus 45 1/s; P<0.001). Total helicity computed correlated with the cardiac magnetic resonance imaging–derived ventricular‐vascular coupling (−0.927; P<0.000), the RV ejection fraction (0.865; P<0.0001), cardiac output (0.581; P<0.0001), mean pulmonary arterial pressure (−0.581; P=0.0008), and relative area change measured at the MPA (0.789; P<0.0001). Conclusions The flow hemodynamic character in patients with PH assessed via quantitative analysis is considerably different when compared with healthy and normotensive controls. A strong association between helicity in pulmonary arteries and ventricular‐vascular coupling suggests a relationship between the mechanical and flow hemodynamic domains.
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Affiliation(s)
- Michal Schäfer
- Division of Cardiology, National Jewish Health, Denver, CO .,Division of Cardiology, Children's Hospital Colorado, Aurora, CO.,Department of Bioengineering, University of Colorado Denver
- Anschutz Medical Campus, Denver, CO
| | - Alex J Barker
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL
| | - Vitaly Kheyfets
- Department of Bioengineering, University of Colorado Denver
- Anschutz Medical Campus, Denver, CO
| | - Kurt R Stenmark
- Department of Bioengineering, University of Colorado Denver
- Anschutz Medical Campus, Denver, CO.,Pediatric Division, Department of Critical Care and Pulmonary Medicine, University of Colorado Denver
- Anschutz Medical Campus, Denver, CO
| | - James Crapo
- Division of Pulmonary Medicine, National Jewish Health, Denver, CO
| | - Michael E Yeager
- Department of Bioengineering, University of Colorado Denver
- Anschutz Medical Campus, Denver, CO
| | - Uyen Truong
- Division of Cardiology, National Jewish Health, Denver, CO.,Department of Bioengineering, University of Colorado Denver
- Anschutz Medical Campus, Denver, CO
| | - J Kern Buckner
- Division of Cardiology, National Jewish Health, Denver, CO
| | | | - Kendall S Hunter
- Division of Cardiology, National Jewish Health, Denver, CO.,Department of Bioengineering, University of Colorado Denver
- Anschutz Medical Campus, Denver, CO
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Coolen BF, Calcagno C, van Ooij P, Fayad ZA, Strijkers GJ, Nederveen AJ. Vessel wall characterization using quantitative MRI: what's in a number? MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2017; 31:201-222. [PMID: 28808823 PMCID: PMC5813061 DOI: 10.1007/s10334-017-0644-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 07/04/2017] [Accepted: 07/18/2017] [Indexed: 12/15/2022]
Abstract
The past decade has witnessed the rapid development of new MRI technology for vessel wall imaging. Today, with advances in MRI hardware and pulse sequences, quantitative MRI of the vessel wall represents a real alternative to conventional qualitative imaging, which is hindered by significant intra- and inter-observer variability. Quantitative MRI can measure several important morphological and functional characteristics of the vessel wall. This review provides a detailed introduction to novel quantitative MRI methods for measuring vessel wall dimensions, plaque composition and permeability, endothelial shear stress and wall stiffness. Together, these methods show the versatility of non-invasive quantitative MRI for probing vascular disease at several stages. These quantitative MRI biomarkers can play an important role in the context of both treatment response monitoring and risk prediction. Given the rapid developments in scan acceleration techniques and novel image reconstruction, we foresee the possibility of integrating the acquisition of multiple quantitative vessel wall parameters within a single scan session.
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Affiliation(s)
- Bram F Coolen
- Department of Biomedical Engineering and Physics, Academic Medical Center, PO BOX 22660, 1100 DD, Amsterdam, The Netherlands. .,Department of Radiology, Academic Medical Center, Amsterdam, The Netherlands.
| | - Claudia Calcagno
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Pim van Ooij
- Department of Radiology, Academic Medical Center, Amsterdam, The Netherlands
| | - Zahi A Fayad
- Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Gustav J Strijkers
- Department of Biomedical Engineering and Physics, Academic Medical Center, PO BOX 22660, 1100 DD, Amsterdam, The Netherlands
| | - Aart J Nederveen
- Department of Radiology, Academic Medical Center, Amsterdam, The Netherlands
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43
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Padormo F, Beqiri A, Hajnal JV, Malik SJ. Parallel transmission for ultrahigh-field imaging. NMR IN BIOMEDICINE 2016; 29:1145-61. [PMID: 25989904 PMCID: PMC4995736 DOI: 10.1002/nbm.3313] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Revised: 03/27/2015] [Accepted: 03/29/2015] [Indexed: 05/24/2023]
Abstract
The development of MRI systems operating at or above 7 T has provided researchers with a new window into the human body, yielding improved imaging speed, resolution and signal-to-noise ratio. In order to fully realise the potential of ultrahigh-field MRI, a range of technical hurdles must be overcome. The non-uniformity of the transmit field is one of such issues, as it leads to non-uniform images with spatially varying contrast. Parallel transmission (i.e. the use of multiple independent transmission channels) provides previously unavailable degrees of freedom that allow full spatial and temporal control of the radiofrequency (RF) fields. This review discusses the many ways in which these degrees of freedom can be used, ranging from making more uniform transmit fields to the design of subject-tailored RF pulses for both uniform excitation and spatial selection, and also the control of the specific absorption rate. © 2015 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd.
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Affiliation(s)
- Francesco Padormo
- Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St Thomas' Hospital, London, UK
| | - Arian Beqiri
- Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St Thomas' Hospital, London, UK
| | - Joseph V Hajnal
- Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St Thomas' Hospital, London, UK
- Centre for the Developing Brain, Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St Thomas' Hospital, London, UK
| | - Shaihan J Malik
- Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St Thomas' Hospital, London, UK
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Niendorf T, Paul K, Oezerdem C, Graessl A, Klix S, Huelnhagen T, Hezel F, Rieger J, Waiczies H, Frahm J, Nagel AM, Oberacker E, Winter L. W(h)ither human cardiac and body magnetic resonance at ultrahigh fields? technical advances, practical considerations, applications, and clinical opportunities. NMR IN BIOMEDICINE 2016; 29:1173-97. [PMID: 25706103 DOI: 10.1002/nbm.3268] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 12/26/2014] [Accepted: 01/13/2015] [Indexed: 05/12/2023]
Abstract
The objective of this study was to document and review advances and groundbreaking progress in cardiac and body MR at ultrahigh fields (UHF, B0 ≥ 7.0 T) with the goal to attract talent, clinical adopters, collaborations and resources to the biomedical and diagnostic imaging communities. This review surveys traits, advantages and challenges of cardiac and body MR at 7.0 T. The considerations run the gamut from technical advances to clinical opportunities. Key concepts, emerging technologies, practical considerations, frontier applications and future directions of UHF body and cardiac MR are provided. Examples of UHF cardiac and body imaging strategies are demonstrated. Their added value over the kindred counterparts at lower fields is explored along with an outline of research promises. The achievements of cardiac and body UHF-MR are powerful motivators and enablers, since extra speed, signal and imaging capabilities may be invested to overcome the fundamental constraints that continue to hamper traditional cardiac and body MR applications. If practical obstacles, concomitant physics effects and technical impediments can be overcome in equal measure, sophisticated cardiac and body UHF-MR will help to open the door to new MRI and MRS approaches for basic research and clinical science, with the lessons learned at 7.0 T being transferred into broad clinical use including diagnostics and therapy guiding at lower fields. Copyright © 2015 John Wiley & Sons, Ltd.
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Affiliation(s)
- Thoralf Niendorf
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site, Berlin, Germany
| | - Katharina Paul
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Celal Oezerdem
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Andreas Graessl
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Sabrina Klix
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Till Huelnhagen
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Fabian Hezel
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | | | | | - Jens Frahm
- Biomedizinische NMR Forschungs GmbH, am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site, Göttingen, Germany
| | - Armin M Nagel
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Eva Oberacker
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Lukas Winter
- Berlin Ultrahigh Field Facility (BUFF), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany
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45
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Schmitter S, Schnell S, Uğurbil K, Markl M, Van de Moortele PF. Towards high-resolution 4D flow MRI in the human aorta using kt-GRAPPA and B1+ shimming at 7T. J Magn Reson Imaging 2016; 44:486-99. [PMID: 26841070 DOI: 10.1002/jmri.25164] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Accepted: 01/05/2016] [Indexed: 01/27/2023] Open
Abstract
PURPOSE To evaluate the feasibility of aortic 4D flow magnetic resonance imaging (MRI) at 7T with improved spatial resolution using kt-GRAPPA acceleration while restricting acquisition time and to address radiofrequency (RF) excitation heterogeneities with B1+ shimming. MATERIALS AND METHODS 4D flow MRI data were obtained in the aorta of eight subjects using a 16-channel transmit/receive coil array at 7T. Flow quantification and acquisition time were compared for a kt-GRAPPA accelerated (R = 5) and a standard GRAPPA (R = 2) accelerated protocol. The impact of different dynamic B1+ shimming strategies on flow quantification was investigated. Two kt-GRAPPA accelerated protocols with 1.2 × 1.2 × 1.2 mm(3) and 1.8 × 1.8 × 2.4 mm(3) spatial resolution were compared. RESULTS Using kt-GRAPPA, we achieved a 4.3-fold reduction in net acquisition time resulting in scan times of about 10 minutes. No significant effect on flow quantification was observed compared to standard GRAPPA with R = 2. Optimizing the B1+ fields for the aorta impacted significantly (P < 0.05) the flow quantification while specific B1+ settings were required for respiration navigators. The high-resolution protocol yielded similar flow quantification, but allowed the depiction of branching vessels. CONCLUSION 7T in combination with B1+ shimming allows for high-resolution 4D flow MRI acquisitions in the human aorta, while kt-GRAPPA limits total scan times without affecting flow quantification. J. Magn. Reson. Imaging 2016;44:486-499.
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Affiliation(s)
- Sebastian Schmitter
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Susanne Schnell
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Kâmil Uğurbil
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Michael Markl
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, Illinois, USA
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Donati F, Figueroa CA, Smith NP, Lamata P, Nordsletten DA. Non-invasive pressure difference estimation from PC-MRI using the work-energy equation. Med Image Anal 2015; 26:159-72. [PMID: 26409245 PMCID: PMC4686008 DOI: 10.1016/j.media.2015.08.012] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 08/21/2015] [Accepted: 08/31/2015] [Indexed: 01/15/2023]
Abstract
Pressure difference is an accepted clinical biomarker for cardiovascular disease conditions such as aortic coarctation. Currently, measurements of pressure differences in the clinic rely on invasive techniques (catheterization), prompting development of non-invasive estimates based on blood flow. In this work, we propose a non-invasive estimation procedure deriving pressure difference from the work-energy equation for a Newtonian fluid. Spatial and temporal convergence is demonstrated on in silico Phase Contrast Magnetic Resonance Image (PC-MRI) phantoms with steady and transient flow fields. The method is also tested on an image dataset generated in silico from a 3D patient-specific Computational Fluid Dynamics (CFD) simulation and finally evaluated on a cohort of 9 subjects. The performance is compared to existing approaches based on steady and unsteady Bernoulli formulations as well as the pressure Poisson equation. The new technique shows good accuracy, robustness to noise, and robustness to the image segmentation process, illustrating the potential of this approach for non-invasive pressure difference estimation.
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Affiliation(s)
- Fabrizio Donati
- King's College London, Department of Biomedical Engineering and Imaging Sciences, St. Thomas' Hospital, 4th floor Lambeth Wing, The Rayne Institute, London SE1 7EH, United Kingdom.
| | - C Alberto Figueroa
- University of Michigan, North Campus Research Complex, 2800 Plymouth Road, Ann Arbor, MI 48105, United States.
| | - Nicolas P Smith
- King's College London, Department of Biomedical Engineering and Imaging Sciences, St. Thomas' Hospital, 4th floor Lambeth Wing, The Rayne Institute, London SE1 7EH, United Kingdom; University of Auckland, Engineering School Block 1, Level 5, 20 Symonds St, Auckland 101, New Zealand.
| | - Pablo Lamata
- King's College London, Department of Biomedical Engineering and Imaging Sciences, St. Thomas' Hospital, 4th floor Lambeth Wing, The Rayne Institute, London SE1 7EH, United Kingdom; University of Oxford, Department of Computer Science, Wolfson Building, Parks Road, Oxford OX1 3QD, United Kingdom.
| | - David A Nordsletten
- King's College London, Department of Biomedical Engineering and Imaging Sciences, St. Thomas' Hospital, 4th floor Lambeth Wing, The Rayne Institute, London SE1 7EH, United Kingdom.
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47
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Dyverfeldt P, Bissell M, Barker AJ, Bolger AF, Carlhäll CJ, Ebbers T, Francios CJ, Frydrychowicz A, Geiger J, Giese D, Hope MD, Kilner PJ, Kozerke S, Myerson S, Neubauer S, Wieben O, Markl M. 4D flow cardiovascular magnetic resonance consensus statement. J Cardiovasc Magn Reson 2015; 17:72. [PMID: 26257141 PMCID: PMC4530492 DOI: 10.1186/s12968-015-0174-5] [Citation(s) in RCA: 543] [Impact Index Per Article: 60.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 07/17/2015] [Indexed: 02/07/2023] Open
Abstract
Pulsatile blood flow through the cavities of the heart and great vessels is time-varying and multidirectional. Access to all regions, phases and directions of cardiovascular flows has formerly been limited. Four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) has enabled more comprehensive access to such flows, with typical spatial resolution of 1.5×1.5×1.5 - 3×3×3 mm(3), typical temporal resolution of 30-40 ms, and acquisition times in the order of 5 to 25 min. This consensus paper is the work of physicists, physicians and biomedical engineers, active in the development and implementation of 4D Flow CMR, who have repeatedly met to share experience and ideas. The paper aims to assist understanding of acquisition and analysis methods, and their potential clinical applications with a focus on the heart and greater vessels. We describe that 4D Flow CMR can be clinically advantageous because placement of a single acquisition volume is straightforward and enables flow through any plane across it to be calculated retrospectively and with good accuracy. We also specify research and development goals that have yet to be satisfactorily achieved. Derived flow parameters, generally needing further development or validation for clinical use, include measurements of wall shear stress, pressure difference, turbulent kinetic energy, and intracardiac flow components. The dependence of measurement accuracy on acquisition parameters is considered, as are the uses of different visualization strategies for appropriate representation of time-varying multidirectional flow fields. Finally, we offer suggestions for more consistent, user-friendly implementation of 4D Flow CMR acquisition and data handling with a view to multicenter studies and more widespread adoption of the approach in routine clinical investigations.
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Affiliation(s)
- Petter Dyverfeldt
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.
- Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden.
| | - Malenka Bissell
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, UK.
| | - Alex J Barker
- Department of Radiology, Northwestern University, Chicago, USA.
| | - Ann F Bolger
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.
- Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden.
- Department of Medicine, University of California San Francisco, San Francisco, CA, United States.
| | - Carl-Johan Carlhäll
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.
- Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden.
- Department of Clinical Physiology, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.
| | - Tino Ebbers
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.
- Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden.
| | | | - Alex Frydrychowicz
- Klinik für Radiologie und Nuklearmedizin, University Hospital Schleswig-Holstein, Campus Lübeck, Lübeck, Germany.
| | - Julia Geiger
- Department of Radiology, University Children's Hospital Zurich, Zurich, Switzerland.
| | - Daniel Giese
- Department of Radiology, University Hospital of Cologne, Cologne, Germany.
| | - Michael D Hope
- Department of Radiology, University of California San Francisco, San Francisco, CA, United States.
| | - Philip J Kilner
- NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, National Heart and Lung Institute, Imperial College, London, UK.
| | - Sebastian Kozerke
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland.
| | - Saul Myerson
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, UK.
| | - Stefan Neubauer
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford Centre for Clinical Magnetic Resonance Research, Oxford, UK.
| | - Oliver Wieben
- Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA.
- Department of Medical Physics, University of Wisconsin, Madison, Wisconsin, USA.
| | - Michael Markl
- Department of Radiology, Northwestern University, Chicago, USA.
- Department of Biomedical Engineering, Northwestern University, Chicago, IL, USA.
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