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Zhang M, Olivero WC, Huston JM, Pappu S, Arnold PM, Biswas A, Anderson AT, Sutton BP. Measuring CSF shunt flow with MRI using flow enhancement of signal intensity (FENSI). Magn Reson Med 2024. [PMID: 38469904 DOI: 10.1002/mrm.30079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 02/18/2024] [Accepted: 02/21/2024] [Indexed: 03/13/2024]
Abstract
PURPOSE To develop and validate a noninvasive imaging technique for accurately assessing very slow CSF flow within shunt tubes in pediatric patients with hydrocephalus, aiming to identify obstructions that might impede CSF drainage. THEORY AND METHODS A simulation of shunt flow enhancement of signal intensity (shunt-FENSI) signal is used to establish the relationship between signal change and flow rate. The quantification of flow enhancement of signal intensity data involves normalization, curve fitting, and calibration to match simulated data. Additionally, a phase sweep method is introduced to accommodate the impact of magnetic field inhomogeneity on the flow measurement. The method is tested in flow phantoms, healthy adults, intensive care unit patients with external ventricular drains (EVD), and shunt patients. EVDs enable shunt-flow measurements to be acquired with a ground truth measure of CSF drainage. RESULTS The flow-rate-to-signal simulation establishes signal-flow relationships and takes into account the T1 of draining fluid. The phase sweep method accurately accounts for phase accumulation due to frequency offsets at the shunt. Results in phantom and healthy human participants reveal reliable quantification of flow rates using controlled flows and agreement with the flow simulation. EVD patients display reliable measures of flow rates. Shunt patient results demonstrate feasibility of the method and consistent flow rates for functional shunts. CONCLUSION The results demonstrate the technique's applicability, accuracy, and potential for diagnosing and noninvasively monitoring hydrocephalus. Limitations of the current approach include a high sensitivity to motion and strict requirement of imaging slice prescription.
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Affiliation(s)
- Mingxiao Zhang
- Department of Bioengineering, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
- Beckman Institute, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - William C Olivero
- Carle Illinois College of Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
- Department of Neurosurgery, Carle Foundation Hospital, Urbana, Illinois, USA
| | - Jason M Huston
- Carle Illinois College of Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
- Department of Radiology, Carle Foundation Hospital, Urbana, Illinois, USA
| | - Suguna Pappu
- Carle Illinois College of Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
- Department of Neurosurgery, Carle Foundation Hospital, Urbana, Illinois, USA
| | - Paul M Arnold
- Carle Illinois College of Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
- Department of Neurosurgery, Carle Foundation Hospital, Urbana, Illinois, USA
| | - Arundhati Biswas
- Department of Neurosurgery, Carle Foundation Hospital, Urbana, Illinois, USA
| | - Aaron T Anderson
- Beckman Institute, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Bradley P Sutton
- Department of Bioengineering, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
- Beckman Institute, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
- Carle Illinois College of Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
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2
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McGrath C, Bieri O, Kozerke S, Bauman G. Self-gated cine phase-contrast balanced SSFP flow quantification at 0.55 T. Magn Reson Med 2024; 91:174-189. [PMID: 37668108 DOI: 10.1002/mrm.29837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 07/13/2023] [Accepted: 08/02/2023] [Indexed: 09/06/2023]
Abstract
PURPOSE To implement cine phase-contrast balanced SSFP (PC-bSSFP) for low-field 0.55T cardiac MRI by exploiting the intrinsic flow sensitivity of the bSSFP slice-select gradient and the in-plane phase-cancelation properties of radial trajectories, enabling self-gated and referenceless PC-bSSFP flow quantification at 0.55 T. METHODS A free-running, tiny golden-angle radial PC-bSSFP approach was implemented on 0.55T and 1.5T systems. Cardiac and respiratory self-gating was incorporated to enable electrocardiogram-free scanning during breath-hold and free-breathing. By exploiting the intrinsic in-plane phase-cancelation properties of radial acquisitions and background phase fitting, referenceless single-point PC-bSSFP was realized. In vivo data were acquired in the ascending aorta of healthy subjects at 0.55 T and 1.5 T during breath-hold and free-breathing. Flow data, SNR, and velocity-to-noise ratio were compared relative to data obtained with phase-contrast spoiled gradient-echo variants. RESULTS Velocities acquired with PC-bSSFP compared well with data from phase-contrast spoiled gradient-echo (RMSEv = 5.8 cm/s). PC-bSSFP at 0.55 T resulted in high-quality cine magnitude images and phase maps with sufficient SNR and velocity-to-noise ratio. Breath-hold and free-breathing PC-bSSFP performed very similarly, with comparable flow quantification (RMSEv = 5.7 cm/s). Referenceless single-point PC-bSSFP results agreed well with two-point PC-bSSFP (-1.8 ± 5.2 cm/s) while reducing scan times 2-fold. CONCLUSION PC-bSSFP is feasible on low-field 0.55T systems, producing high-quality cine images while permitting simultaneous aortic flow measurements during breath-hold and free-breathing and without the need for electrocardiogram gating.
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Affiliation(s)
- Charles McGrath
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - Oliver Bieri
- Division of Radiological Physics, Department of Radiology, University Hospital Basel, Basel, Switzerland
- Department of Biomedical Engineering, University of Basel, Basel, Switzerland
| | - Sebastian Kozerke
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - Grzegorz Bauman
- Division of Radiological Physics, Department of Radiology, University Hospital Basel, Basel, Switzerland
- Department of Biomedical Engineering, University of Basel, Basel, Switzerland
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Li R, Assadi H, Matthews G, Mehmood Z, Grafton-Clarke C, Kasmai B, Hewson D, Greenwood R, Spohr H, Zhong L, Zhao X, Sawh C, Duehmke R, Vassiliou VS, Nelthorpe F, Ashman D, Curtin J, Yashoda GK, Van der Geest RJ, Alabed S, Swift AJ, Hughes M, Garg P. The Importance of Mitral Valve Prolapse Doming Volume in the Assessment of Left Ventricular Stroke Volume with Cardiac MRI. Med Sci (Basel) 2023; 11:medsci11010013. [PMID: 36810480 PMCID: PMC9945133 DOI: 10.3390/medsci11010013] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/20/2023] [Accepted: 01/20/2023] [Indexed: 01/26/2023] Open
Abstract
There remains a debate whether the ventricular volume within prolapsing mitral valve (MV) leaflets should be included in the left ventricular (LV) end-systolic volume, and therefore factored in LV stroke volume (SV), in cardiac magnetic resonance (CMR) assessments. This study aims to compare LV volumes during end-systolic phases, with and without the inclusion of the volume of blood on the left atrial aspect of the atrioventricular groove but still within the MV prolapsing leaflets, against the reference LV SV by four-dimensional flow (4DF). A total of 15 patients with MV prolapse (MVP) were retrospectively enrolled in this study. We compared LV SV with (LV SVMVP) and without (LV SVstandard) MVP left ventricular doming volume, using 4D flow (LV SV4DF) as the reference value. Significant differences were observed when comparing LV SVstandard and LV SVMVP (p < 0.001), and between LV SVstandard and LV SV4DF (p = 0.02). The Intraclass Correlation Coefficient (ICC) test demonstrated good repeatability between LV SVMVP and LV SV4DF (ICC = 0.86, p < 0.001) but only moderate repeatability between LV SVstandard and LV SV4DF (ICC = 0.75, p < 0.01). Calculating LV SV by including the MVP left ventricular doming volume has a higher consistency with LV SV derived from the 4DF assessment. In conclusion, LV SV short-axis cine assessment incorporating MVP dooming volume can significantly improve the precision of LV SV assessment compared to the reference 4DF method. Hence, in cases with bi-leaflet MVP, we recommend factoring in MVP dooming into the left ventricular end-systolic volume to improve the accuracy and precision of quantifying mitral regurgitation.
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Affiliation(s)
- Rui Li
- Norwich Medical School, University of East Anglia, Norfolk NR4 7TJ, UK
- Norfolk and Norwich University Hospitals NHS Foundation Trust, Norfolk NR4 7UY, UK
| | - Hosamadin Assadi
- Norwich Medical School, University of East Anglia, Norfolk NR4 7TJ, UK
- Norfolk and Norwich University Hospitals NHS Foundation Trust, Norfolk NR4 7UY, UK
| | - Gareth Matthews
- Norwich Medical School, University of East Anglia, Norfolk NR4 7TJ, UK
- Norfolk and Norwich University Hospitals NHS Foundation Trust, Norfolk NR4 7UY, UK
| | - Zia Mehmood
- Norfolk and Norwich University Hospitals NHS Foundation Trust, Norfolk NR4 7UY, UK
| | | | - Bahman Kasmai
- Norwich Medical School, University of East Anglia, Norfolk NR4 7TJ, UK
- Norfolk and Norwich University Hospitals NHS Foundation Trust, Norfolk NR4 7UY, UK
| | - David Hewson
- Norwich Medical School, University of East Anglia, Norfolk NR4 7TJ, UK
- Norfolk and Norwich University Hospitals NHS Foundation Trust, Norfolk NR4 7UY, UK
| | - Richard Greenwood
- Norwich Medical School, University of East Anglia, Norfolk NR4 7TJ, UK
- Norfolk and Norwich University Hospitals NHS Foundation Trust, Norfolk NR4 7UY, UK
| | - Hilmar Spohr
- Norfolk and Norwich University Hospitals NHS Foundation Trust, Norfolk NR4 7UY, UK
| | - Liang Zhong
- National Heart Research Institute Singapore, National Heart Centre Singapore, 5 Hospital Drive, Singapore 169609, Singapore
- Cardiovascular Sciences Academic Clinical Programme, Duke-NUS Medical School, 8 College Road, Singapore 169856, Singapore
| | - Xiaodan Zhao
- National Heart Research Institute Singapore, National Heart Centre Singapore, 5 Hospital Drive, Singapore 169609, Singapore
| | - Chris Sawh
- Norfolk and Norwich University Hospitals NHS Foundation Trust, Norfolk NR4 7UY, UK
| | - Rudolf Duehmke
- Cardiology Department, Queen Elizabeth Hospital King’s Lynn NHS Foundation Trust, King’s Lynn PE30 4ET, UK
| | - Vassilios S. Vassiliou
- Norwich Medical School, University of East Anglia, Norfolk NR4 7TJ, UK
- Norfolk and Norwich University Hospitals NHS Foundation Trust, Norfolk NR4 7UY, UK
| | - Faye Nelthorpe
- Norfolk and Norwich University Hospitals NHS Foundation Trust, Norfolk NR4 7UY, UK
| | - David Ashman
- Norfolk and Norwich University Hospitals NHS Foundation Trust, Norfolk NR4 7UY, UK
| | - John Curtin
- Norwich Medical School, University of East Anglia, Norfolk NR4 7TJ, UK
- Norfolk and Norwich University Hospitals NHS Foundation Trust, Norfolk NR4 7UY, UK
| | - Gurung-Koney Yashoda
- Norfolk and Norwich University Hospitals NHS Foundation Trust, Norfolk NR4 7UY, UK
| | - Rob J. Van der Geest
- Department of Radiology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - Samer Alabed
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield S10 2TN, UK
- Department of Clinical Radiology, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield S10 2JF, UK
| | - Andrew J. Swift
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield S10 2TN, UK
- Department of Clinical Radiology, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield S10 2JF, UK
| | - Marina Hughes
- Norwich Medical School, University of East Anglia, Norfolk NR4 7TJ, UK
- Norfolk and Norwich University Hospitals NHS Foundation Trust, Norfolk NR4 7UY, UK
| | - Pankaj Garg
- Norwich Medical School, University of East Anglia, Norfolk NR4 7TJ, UK
- Norfolk and Norwich University Hospitals NHS Foundation Trust, Norfolk NR4 7UY, UK
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield S10 2TN, UK
- Department of Clinical Radiology, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield S10 2JF, UK
- Correspondence: ; Tel.: +44-016-0359-2534
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Ben-Arzi H, Das A, Kelly C, van der Geest RJ, Plein S, Dall'Armellina E. Longitudinal Changes in Left Ventricular Blood Flow Kinetic Energy After Myocardial Infarction: Predictive Relevance for Cardiac Remodeling. J Magn Reson Imaging 2022; 56:768-778. [PMID: 34854151 DOI: 10.1002/jmri.28015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 11/19/2021] [Accepted: 11/19/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Four-dimensional (4D) flow cardiac magnetic resonance (cardiac MR) imaging provides quantification of intracavity left ventricular (LV) flow kinetic energy (KE) parameters in three dimensions. ST-elevation myocardial infarction (STEMI) patients have been shown to have altered intracardiac blood flow compared to controls; however, how 4D flow parameters change over time has not been explored previously. PURPOSE Measure longitudinal changes in intraventricular flow post-STEMI and ascertain its predictive relevance of long-term cardiac remodeling. STUDY TYPE Prospective. POPULATION Thirty-five STEMI patients (M:F = 26:9, aged 56 ± 9 years). FIELD STRENGTH/SEQUENCE A 3 T/3D EPI-based, fast field echo (FFE) free-breathing 4D-flow sequence with retrospective cardiac gating. ASSESSMENT Serial imaging at 3-7 days (V1), 3-months (V2), and 12-months (V3) post-STEMI, including the following protocol: functional imaging for measuring volumes and 4D-flow for calculating parameters including systolic and peakE-wave LVKE, normalized to end-diastolic volume (iEDV) and stroke volume (iSV). Data were analyzed by H.B. (3 years experience). Patients were categorized into two groups: preserved ejection fraction (pEF, if EF > 50%) and reduced EF (rEF, if EF < 50%). STATISTICAL TESTS Independent sample t-tests were used to detect the statistical significance between any two cohorts. P < 0.05 was considered statistically significant. RESULTS Across the cohort, systolic KEisv was highest at V1 (28.0 ± 4.4 μJ/mL). Patients with rEF retained significantly higher systolic KEisv than patients with pEF at V2 (18.2 ± 3.4 μJ/mL vs. 6.9 ± 0.6 μJ/mL, P < 0.001) and V3 (21.6 ± 5.1 μJ/mL vs. 7.4 ± 0.9 μJ/mL, P < 0.001). Patients with pEF had significantly higher peakE-wave KEiEDV than rEF patients throughout the study (V1: 25.4 ± 11.6 μJ/mL vs. 18.1 ± 9.9 μJ/mL, P < 0.03, V2: 24.0 ± 10.2 μJ/mL vs. 17.2 ± 12.2 μJ/mL, P < 0.05, V3: 27.7 ± 14.8 μJ/mL vs. 15.8 ± 7.6 μJ/mL, P < 0.04). DATA CONCLUSION Systolic KE increased acutely following MI; in patients with pEF, this decreased over 12 months, while patients with rEF, this remained raised. Compared to patients with pEF, persistently lower peakE-wave KE in rEF patients is suggestive of early and fixed impairment in diastolic function. EVIDENCE LEVEL 1 TECHNICAL EFFICACY: Stage 3.
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Affiliation(s)
- Hadar Ben-Arzi
- LICAMM, Department of Biomedical Imaging Sciences, University of Leeds, Leeds, UK
| | - Arka Das
- LICAMM, Department of Biomedical Imaging Sciences, University of Leeds, Leeds, UK
| | - Christopher Kelly
- LICAMM, Department of Biomedical Imaging Sciences, University of Leeds, Leeds, UK
| | - Rob J van der Geest
- The Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Sven Plein
- LICAMM, Department of Biomedical Imaging Sciences, University of Leeds, Leeds, UK
| | - Erica Dall'Armellina
- LICAMM, Department of Biomedical Imaging Sciences, University of Leeds, Leeds, UK
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5
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Fischer C, Wetzl J, Schaeffter T, Giese D. Fully automated background phase correction using M-estimate SAmple consensus (MSAC)-Application to 2D and 4D flow. Magn Reson Med 2022; 88:2709-2717. [PMID: 35916368 DOI: 10.1002/mrm.29363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 05/11/2022] [Accepted: 05/25/2022] [Indexed: 11/07/2022]
Abstract
PURPOSE Flow quantification by phase-contrast MRI is hampered by spatially varying background phase offsets. Correction performance by polynomial regression on stationary tissue may be affected by outliers such as wrap-around or constant flow. Therefore, we propose an alternative, M-estimate SAmple Consensus (MSAC) to reject outliers, and improve and fully automate background phase correction. METHODS The MSAC technique fits polynomials to randomly drawn small samples from the image. Over several trials, it aims to find the best consensus set of valid pixels by rejecting outliers to the fit and minimizing the residuals of the remaining pixels. The robustness of MSAC to its few parameters was investigated and verified using third-order polynomial correction fits on a total of 118 2D flow (97 with wrap-around) and 18 4D flow data sets (14 with wrap-around), acquired at 1.5 T and 3 T. Background phase was compared with standard stationary correction and phantom correction. Pulmonary/systemic flow ratios in 2D flow were derived, and exemplary 4D flow analysis was performed. RESULTS The MSAC technique is robust over a range of parameter choices, and a unique set of parameters is suitable for both 2D and 4D flow. In 2D flow, phase errors were significantly reduced by MSAC compared with stationary correction (p = 0.005), and stationary correction shows larger errors in pulmonary/systemic flow ratios compared with MSAC. In 4D flow, MSAC shows similar performance as stationary correction. CONCLUSIONS The MSAC method provides fully automated background phase correction to 2D and 4D flow data and shows improved robustness over stationary correction, especially with outliers present.
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Affiliation(s)
- Carola Fischer
- Department of Medical Imaging, Technical University of Berlin, Berlin, Germany.,Magnetic Resonance, Siemens Healthcare, Erlangen, Germany
| | - Jens Wetzl
- Magnetic Resonance, Siemens Healthcare, Erlangen, Germany
| | - Tobias Schaeffter
- Department of Medical Imaging, Technical University of Berlin, Berlin, Germany.,Biomedical Imaging, Physikalisch-Technische Bundesanstalt, Braunschweig and Berlin, Berlin, Germany.,School of Imaging Sciences and Biomedical Engineering, King's College London, London, UK
| | - Daniel Giese
- Magnetic Resonance, Siemens Healthcare, Erlangen, Germany.,Institute of Radiology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), University Hospital Erlangen, Erlangen, Germany
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6
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Chatelin S, Pop R, Giraudeau C, Ambarki K, Jin N, Séverac F, Breton E, Vappou J. Influence of portal vein occlusion on portal flow and liver elasticity in an animal model. NMR Biomed 2021; 34:e4498. [PMID: 33634498 DOI: 10.1002/nbm.4498] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 02/11/2021] [Indexed: 06/12/2023]
Abstract
Hepatic fibrosis causes an increase in liver stiffness, a parameter measured by elastography and widely used as a diagnosis method. The concomitant presence of portal vein thrombosis (PVT) implies a change in hepatic portal inflow that could also affect liver elasticity. The main objective of this study is to determine the extent to which the presence of portal occlusion can affect the mechanical properties of the liver and potentially lead to misdiagnosis of fibrosis and hepatic cirrhosis by elastography. Portal vein occlusion was generated by insertion and inflation of a balloon catheter in the portal vein of four swines. The portal flow parameters peak flow (PF) and peak velocity magnitude (PVM) and liver mechanical properties (shear modulus) were then investigated using 4D-flow MRI and MR elastography, respectively, for progressive obstructions of the portal vein. Experimental results indicate that the reduction of the intrahepatic venous blood flow (PF/PVM decreases of 29.3%/8.5%, 51.0%/32.3% and 83.3%/53.6%, respectively) measured with 50%, 80% and 100% obstruction of the portal vein section results in a decrease of liver stiffness by 0.8% ± 0.1%, 7.7% ± 0.4% and 12.3% ± 0.9%, respectively. While this vascular mechanism does not have sufficient influence on the elasticity of the liver to modify the diagnosis of severe fibrosis or cirrhosis (F4 METAVIR grade), it may be sufficient to attenuate the increase in stiffness due to moderate fibrosis (F2-F3 METAVIR grades) and consequently lead to false-negative diagnoses with elastography in the presence of PVT.
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Affiliation(s)
- Simon Chatelin
- ICube, CNRS UMR 7357, University of Strasbourg, Strasbourg, France
| | - Raoul Pop
- IHU-Strasbourg, Institute for Image-Guided Surgery, Strasbourg, France
- Interventional Neuroradiology Department, University Hospital of Strasbourg, Strasbourg, France
| | - Céline Giraudeau
- IHU-Strasbourg, Institute for Image-Guided Surgery, Strasbourg, France
| | | | - Ning Jin
- Siemens Medical Solutions USA, Inc., Chicago, Illinois, USA
| | - François Séverac
- ICube, CNRS UMR 7357, University of Strasbourg, Strasbourg, France
- Public Healthcare Department, University Hospitals Strasbourg, Strasbourg, France
| | - Elodie Breton
- ICube, CNRS UMR 7357, University of Strasbourg, Strasbourg, France
| | - Jonathan Vappou
- ICube, CNRS UMR 7357, University of Strasbourg, Strasbourg, France
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Myerson SG. CMR in Evaluating Valvular Heart Disease: Diagnosis, Severity, and Outcomes. JACC Cardiovasc Imaging 2020:S1936-878X(20)30913-X. [PMID: 33248967 DOI: 10.1016/j.jcmg.2020.09.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 09/04/2020] [Accepted: 09/14/2020] [Indexed: 01/20/2023]
Abstract
Cardiac magnetic resonance (CMR) is a versatile imaging tool that brings much to the assessment of valvular heart disease. Although it is best known for myocardial imaging (even in valve disease), it provides excellent assessment of all 4 heart valves, with some distinct advantages, including a free choice of image planes and accurate flow and volumetric quantification. These allow the severity of each valve lesion to be characterized, in addition to optimal visualization of the surrounding outflow tracts and vessels, to deliver a comprehensive package. It can assess each valve lesion separately (in multiple valve disease) and is not affected by hemodynamic status. The accurate quantitation of regurgitant lesions and the ability to characterize myocardial changes also provides an ability to predict future clinical outcomes in asymptomatic patients. This review outlines how CMR can be used in cardiac valve disease to compliment echocardiography and enhance the patient assessment. It covers the main CMR methods used, their strengths and limitations, and the optimal way to apply them to evaluate valve disease.
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8
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Zhou L, Zhang Q, Spincemaille P, Nguyen TD, Morgan J, Dai W, Li Y, Gupta A, Prince MR, Wang Y. Quantitative transport mapping (QTM) of the kidney with an approximate microvascular network. Magn Reson Med 2020; 85:2247-2262. [PMID: 33210310 PMCID: PMC7839791 DOI: 10.1002/mrm.28584] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 09/29/2020] [Accepted: 10/12/2020] [Indexed: 12/20/2022]
Abstract
Purpose Proof‐of‐concept study of mapping renal blood flow vector field according to the inverse solution to a mass transport model of time resolved tracer‐labeled MRI data. Theory and Methods To determine tissue perfusion according to the underlying physics of spatiotemporal tracer concentration variation, the mass transport equation is integrated over a voxel with an approximate microvascular network for fitting time‐resolved tracer imaging data. The inverse solution to the voxelized transport equation provides the blood flow vector field, which is referred to as quantitative transport mapping (QTM). A numerical microvascular network modeling the kidney with computational fluid dynamics reference was used to verify the accuracy of QTM and the current Kety’s method that uses a global arterial input function. Multiple post‐label delay arterial spin labeling (ASL) of the kidney on seven subjects was used to assess QTM in vivo feasibility. Results Against the ground truth in the numerical model, the error in flow estimated by QTM (18.6%) was smaller than that in Kety’s method (45.7%, 2.5‐fold reduction). The in vivo kidney perfusion quantification by QTM (cortex: 443 ± 58 mL/100 g/min and medulla: 190 ± 90 mL/100 g/min) was in the range of that by Kety’s method (482 ± 51 mL/100 g/min in the cortex and 242 ± 73 mL/100 g/min in the medulla), and QTM provided better flow homogeneity in the cortex region. Conclusions QTM flow velocity mapping is feasible from multi‐delay ASL MRI data based on inverting the transport equation. In a numerical simulation, QTM with deconvolution in space and time provided more accurate perfusion quantification than Kety’s method with deconvolution in time only.
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Affiliation(s)
- Liangdong Zhou
- Department of Radiology, Weill Medical College of Cornell University, New York, New York, USA
| | - Qihao Zhang
- Department of Radiology, Weill Medical College of Cornell University, New York, New York, USA.,Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, USA
| | - Pascal Spincemaille
- Department of Radiology, Weill Medical College of Cornell University, New York, New York, USA
| | - Thanh D Nguyen
- Department of Radiology, Weill Medical College of Cornell University, New York, New York, USA
| | - John Morgan
- Department of Radiology, Weill Medical College of Cornell University, New York, New York, USA
| | - Weiying Dai
- Department of Computer Science, Binghamton University, Binghamton, New York, USA
| | - Yi Li
- Department of Radiology, Weill Medical College of Cornell University, New York, New York, USA
| | - Ajay Gupta
- Department of Radiology, Weill Medical College of Cornell University, New York, New York, USA
| | - Martin R Prince
- Department of Radiology, Weill Medical College of Cornell University, New York, New York, USA
| | - Yi Wang
- Department of Radiology, Weill Medical College of Cornell University, New York, New York, USA.,Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, USA
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9
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Pruitt AA, Jin N, Liu Y, Simonetti OP, Ahmad R. A method to correct background phase offset for phase-contrast MRI in the presence of steady flow and spatial wrap-around artifact. Magn Reson Med 2018; 81:2424-2438. [PMID: 30431176 DOI: 10.1002/mrm.27572] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 09/13/2018] [Accepted: 09/27/2018] [Indexed: 11/11/2022]
Abstract
PURPOSE Background phase offsets in phase-contrast MRI are often corrected using polynomial regression; however, correction performance degrades when temporally invariant outliers such as steady flow or spatial wrap-around artifact are present. We describe and validate an iterative method called automatic rejection of temporally invariant outliers (ARTO), which excludes these outliers from the fitting process. METHODS The ARTO method iteratively removes pixels with large polynomial regression errors analyzed by a Gaussian mixture model fitting of the residual distribution. A total of 150 trials of a simulated phantom (75 with wrap-around artifact) and 125 phase-contrast MRI cines from 22 healthy subjects (48 with wrap-around artifact) were used for validation. Background phase offsets were corrected using second-order weighted regularized least squares (WRLS) with and without ARTO. Flow volumes after WRLS and WRLS+ARTO corrections were compared with the known truth (phantom) and stationary phantom reference (in vivo) using Bland-Altman analysis. The ratio between the pulmonary flow and the systemic flow was also computed in a subset of 6 subjects. RESULTS In the simulated phantom, compared with WRLS and no correction, correction with WRLS+ARTO produced superior agreement in volumetric flow quantification with the known truth. In vivo, WRLS+ARTO also produced superior agreement with stationary phantom-corrected volumetric flow compared with WRLS and no correction. In data sets with wrap-around artifact, WRLS produced significantly larger variance in the pulmonary flow and systemic flow ratio than stationary phantom correction (P = .0008). CONCLUSION The proposed method provides automatic exclusion of temporally invariant outliers and produces flow quantification results comparable to stationary phantom correction.
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Affiliation(s)
- Aaron A Pruitt
- Biomedical Engineering, Ohio State University, Columbus, Ohio
| | - Ning Jin
- Cardiovascular MR R&D, Siemens Medical Solutions USA, Columbus, Ohio
| | - Yingmin Liu
- Dorothy M. Davis Heart and Lung Research Institute, Ohio State University, Columbus, Ohio
| | - Orlando P Simonetti
- Biomedical Engineering, Ohio State University, Columbus, Ohio.,Dorothy M. Davis Heart and Lung Research Institute, Ohio State University, Columbus, Ohio.,Internal Medicine, Ohio State University, Columbus, Ohio
| | - Rizwan Ahmad
- Biomedical Engineering, Ohio State University, Columbus, Ohio.,Dorothy M. Davis Heart and Lung Research Institute, Ohio State University, Columbus, Ohio.,Electrical and Computer Engineering, Ohio State University, Columbus, Ohio
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10
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Chen CM, Huang YC, Shih CT, Chen YF, Peng SL. MRI-based measurements of whole-brain global cerebral blood flow: Comparison and validation at 1.5T and 3T. J Magn Reson Imaging 2018; 48:1273-1280. [PMID: 29479823 DOI: 10.1002/jmri.25989] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 02/08/2018] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Whole-brain global cerebral blood flow (CBF) determined by MRI techniques, calculated using total CBF (TCBF) from phase-contrast MRI (PC-MRI), and brain parenchyma volume (BPV) from T1 -weighted image, have become increasingly popular in many applications. PURPOSE/HYPOTHESIS To determine if MRI-based measurements of whole-brain global CBF data obtained across different field strengths could be merged, TCBF and BPV data acquired at 1.5T and 3T were compared. STUDY TYPE Prospective study. POPULATION Seventeen healthy subjects (eight females, aged 21-29 years old). FIELD STRENGTH/SEQUENCE Fast spoiled gradient echo (FSPGR) and PC-MRI at both 1.5T and 3T. ASSESSMENT TCBF and BPV data acquired at 1.5T and 3T were compared. STATISTICAL TESTS The relationships of TCBF and whole-brain global CBF between two field strengths were examined by using the Pearson correlation coefficient analysis and intraclass correlation coefficient (ICC). RESULTS Regression analysis revealed a strong correlation between TCBF at two field strengths (R2 = 0.78, P < 0.001), and the ICC was 0.85, suggesting measurements of TCBF at 1.5T were comparable and correlated with those at 3T. There was a significant difference in BPV between field strengths, where the white matter estimate was significantly larger at 1.5T when compared with that at 3T (P < 0.001). When TCBF was further normalized to the brain parenchyma mass to obtain whole-brain global CBF, it only showed a moderate correlation between measurements at the two field strengths (R2 = 0.46, P = 0.003) and lower ICC of 0.66, reflecting the slightly higher interstrength variability in the whole-brain global CBF measurements. DATA CONCLUSION TCBF measurements could be performed equally well with comparable results at both field strengths, but specific attention should be given when TCBF is further normalized to BPV to obtain whole-brain global CBF. LEVEL OF EVIDENCE 1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:1273-1280.
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Affiliation(s)
- Chun-Ming Chen
- Department of Radiology, China Medical University Hospital, Taichung, Taiwan
| | - Yen-Chih Huang
- Department of Radiology, China Medical University Hospital, Taichung, Taiwan
| | - Cheng-Ting Shih
- 3D Printing Medical Research Center, China Medical University Hospital, China Medical University, Taichung, Taiwan
| | - Yung-Fang Chen
- Department of Radiology, China Medical University Hospital, Taichung, Taiwan
| | - Shin-Lei Peng
- Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung, Taiwan
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11
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Tan Z, Hohage T, Kalentev O, Joseph AA, Wang X, Voit D, Merboldt KD, Frahm J. An eigenvalue approach for the automatic scaling of unknowns in model-based reconstructions: Application to real-time phase-contrast flow MRI. NMR Biomed 2017; 30. [PMID: 28960554 DOI: 10.1002/nbm.3835] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 07/25/2017] [Accepted: 08/27/2017] [Indexed: 05/13/2023]
Abstract
The purpose of this work is to develop an automatic method for the scaling of unknowns in model-based nonlinear inverse reconstructions and to evaluate its application to real-time phase-contrast (RT-PC) flow magnetic resonance imaging (MRI). Model-based MRI reconstructions of parametric maps which describe a physical or physiological function require the solution of a nonlinear inverse problem, because the list of unknowns in the extended MRI signal equation comprises multiple functional parameters and all coil sensitivity profiles. Iterative solutions therefore rely on an appropriate scaling of unknowns to numerically balance partial derivatives and regularization terms. The scaling of unknowns emerges as a self-adjoint and positive-definite matrix which is expressible by its maximal eigenvalue and solved by power iterations. The proposed method is applied to RT-PC flow MRI based on highly undersampled acquisitions. Experimental validations include numerical phantoms providing ground truth and a wide range of human studies in the ascending aorta, carotid arteries, deep veins during muscular exercise and cerebrospinal fluid during deep respiration. For RT-PC flow MRI, model-based reconstructions with automatic scaling not only offer velocity maps with high spatiotemporal acuity and much reduced phase noise, but also ensure fast convergence as well as accurate and precise velocities for all conditions tested, i.e. for different velocity ranges, vessel sizes and the simultaneous presence of signals with velocity aliasing. In summary, the proposed automatic scaling of unknowns in model-based MRI reconstructions yields quantitatively reliable velocities for RT-PC flow MRI in various experimental scenarios.
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Affiliation(s)
- Zhengguo Tan
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Thorsten Hohage
- Institut für Numerische und Angewandte Mathematik, Georg-August-Universität, Göttingen, Germany
| | - Oleksandr Kalentev
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Arun A Joseph
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
- DZHK, German Center for Cardiovascular Research, partner site Göttingen, Germany
| | - Xiaoqing Wang
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Dirk Voit
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - K Dietmar Merboldt
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Jens Frahm
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
- DZHK, German Center for Cardiovascular Research, partner site Göttingen, Germany
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12
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Schnerr RS, Jansen JFA, Uludag K, Hofman PAM, Wildberger JE, van Oostenbrugge RJ, Backes WH. Pulsatility of Lenticulostriate Arteries Assessed by 7 Tesla Flow MRI-Measurement, Reproducibility, and Applicability to Aging Effect. Front Physiol 2017; 8:961. [PMID: 29225580 PMCID: PMC5705621 DOI: 10.3389/fphys.2017.00961] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 11/10/2017] [Indexed: 01/26/2023] Open
Abstract
Characterization of flow properties in cerebral arteries with 1.5 and 3 Tesla MRI is usually limited to large cerebral arteries and difficult to evaluate in the small perforating arteries due to insufficient spatial resolution. In this study, we assessed the feasibility to measure blood flow waveforms in the small lenticulostriate arteries with 7 Tesla velocity-sensitive MRI. The middle cerebral artery was included as reference. Imaging was performed in five young and five old healthy volunteers. Flow was calculated by integrating time-varying velocity values over the vascular cross-section. MRI acquisitions were performed twice in each subject to determine reproducibility. From the flow waveforms, the pulsatility index and damping factor were deduced. Reproducibility values, in terms of the intraclass correlation coefficients, were found to be good to excellent. Measured pulsatility index of the lenticulostriate arteries significantly increased and damping factor significantly decreased with age. In conclusion, we demonstrate that blood flow through the lenticostriate arteries can be precisely measured using 7 Tesla MRI and reveal effects of arterial stiffness due to aging. These findings hold promise to provide relevant insights into the pathologies involving perforating cerebral arteries.
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Affiliation(s)
- Roald S Schnerr
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, Maastricht, Netherlands
| | - Jacobus F A Jansen
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, Maastricht, Netherlands.,Faculty of Health, Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Kamil Uludag
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Paul A M Hofman
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, Maastricht, Netherlands.,Faculty of Health, Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Joachim E Wildberger
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, Maastricht, Netherlands.,Faculty of Health, Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University, Maastricht, Netherlands.,Cardiovascular Research Institute Maastricht, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, Netherlands
| | - Robert J van Oostenbrugge
- Cardiovascular Research Institute Maastricht, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, Netherlands.,Department of Neurology, Maastricht University Medical Center, Maastricht, Netherlands
| | - Walter H Backes
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Center, Maastricht, Netherlands.,Faculty of Health, Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University, Maastricht, Netherlands.,Cardiovascular Research Institute Maastricht, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, Netherlands
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13
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Garg P, Westenberg JJM, van den Boogaard PJ, Swoboda PP, Aziz R, Foley JRJ, Fent GJ, Tyl FGJ, Coratella L, ElBaz MSM, van der Geest RJ, Higgins DM, Greenwood JP, Plein S. Comparison of fast acquisition strategies in whole-heart four-dimensional flow cardiac MR: Two-center, 1.5 Tesla, phantom and in vivo validation study. J Magn Reson Imaging 2017; 47:272-281. [PMID: 28470915 PMCID: PMC5801550 DOI: 10.1002/jmri.25746] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 04/07/2017] [Indexed: 01/02/2023] Open
Abstract
Purpose To validate three widely‐used acceleration methods in four‐dimensional (4D) flow cardiac MR; segmented 4D‐spoiled‐gradient‐echo (4D‐SPGR), 4D‐echo‐planar‐imaging (4D‐EPI), and 4D‐k‐t Broad‐use Linear Acquisition Speed‐up Technique (4D‐k‐t BLAST). Materials and Methods Acceleration methods were investigated in static/pulsatile phantoms and 25 volunteers on 1.5 Tesla MR systems. In phantoms, flow was quantified by 2D phase‐contrast (PC), the three 4D flow methods and the time‐beaker flow measurements. The later was used as the reference method. Peak velocity and flow assessment was done by means of all sequences. For peak velocity assessment 2D PC was used as the reference method. For flow assessment, consistency between mitral inflow and aortic outflow was investigated for all pulse‐sequences. Visual grading of image quality/artifacts was performed on a four‐point‐scale (0 = no artifacts; 3 = nonevaluable). Results For the pulsatile phantom experiments, the mean error for 2D PC = 1.0 ± 1.1%, 4D‐SPGR = 4.9 ± 1.3%, 4D‐EPI = 7.6 ± 1.3% and 4D‐k‐t BLAST = 4.4 ± 1.9%. In vivo, acquisition time was shortest for 4D‐EPI (4D‐EPI = 8 ± 2 min versus 4D‐SPGR = 9 ± 3 min, P < 0.05 and 4D‐k‐t BLAST = 9 ± 3 min, P = 0.29). 4D‐EPI and 4D‐k‐t BLAST had minimal artifacts, while for 4D‐SPGR, 40% of aortic valve/mitral valve (AV/MV) assessments scored 3 (nonevaluable). Peak velocity assessment using 4D‐EPI demonstrated best correlation to 2D PC (AV:r = 0.78, P < 0.001; MV:r = 0.71, P < 0.001). Coefficient of variability (CV) for net forward flow (NFF) volume was least for 4D‐EPI (7%) (2D PC:11%, 4D‐SPGR: 29%, 4D‐k‐t BLAST: 30%, respectively). Conclusion In phantom, all 4D flow techniques demonstrated mean error of less than 8%. 4D‐EPI demonstrated the least susceptibility to artifacts, good image quality, modest agreement with the current reference standard for peak intra‐cardiac velocities and the highest consistency of intra‐cardiac flow quantifications. Level of Evidence: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:272–281.
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Affiliation(s)
- Pankaj Garg
- Leeds Institute of Cardiovascular and Metabolic Medicine (LICAMM), University of Leeds, Leeds, United Kingdom
| | | | | | - Peter P Swoboda
- Leeds Institute of Cardiovascular and Metabolic Medicine (LICAMM), University of Leeds, Leeds, United Kingdom
| | - Rahoz Aziz
- Leeds Institute of Cardiovascular and Metabolic Medicine (LICAMM), University of Leeds, Leeds, United Kingdom
| | - James R J Foley
- Leeds Institute of Cardiovascular and Metabolic Medicine (LICAMM), University of Leeds, Leeds, United Kingdom
| | - Graham J Fent
- Leeds Institute of Cardiovascular and Metabolic Medicine (LICAMM), University of Leeds, Leeds, United Kingdom
| | - F G J Tyl
- Leiden University Medical Center, Leiden, The Netherlands
| | - L Coratella
- Leiden University Medical Center, Leiden, The Netherlands
| | | | | | | | - John P Greenwood
- Leeds Institute of Cardiovascular and Metabolic Medicine (LICAMM), University of Leeds, Leeds, United Kingdom
| | - Sven Plein
- Leeds Institute of Cardiovascular and Metabolic Medicine (LICAMM), University of Leeds, Leeds, United Kingdom
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14
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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: 535] [Impact Index Per Article: 59.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 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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15
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Sethi SK, Utriainen DT, Daugherty AM, Feng W, Hewett JJ, Raz N, Haacke EM. Jugular Venous Flow Abnormalities in Multiple Sclerosis Patients Compared to Normal Controls. J Neuroimaging 2015; 25:600-7. [PMID: 25316522 PMCID: PMC4398578 DOI: 10.1111/jon.12183] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 08/13/2014] [Accepted: 09/13/2014] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND To determine if extracranial venous structural and flow abnormalities exist in patients with multiple sclerosis (MS). METHODS Magnetic resonance imaging was used to assess the anatomy and function of major veins in the neck in 138 MS patients and 67 healthy controls (HC). Time-of-flight MR angiography (MRA) was used to assess stenosis while 2-dimensional phase-contrast flow quantification was used to assess flow at the C2/C3 and C5/C6 levels. Venous flow was normalized to the total arterial flow. The MS patients were divided into stenotic (ST) and nonstenotic (NST) groups based on MRA assessment, and each group was compared to the HC group in anatomy and flow. RESULTS The MS group showed lower normalized internal jugular vein (IJV) blood flow (tIJV/tA) than the HC group (P < .001). In the MS group, 72 (52%) were classified as ST while 66 (48%) were NST. In the HC group, 11 (23%) were ST while 37 (77%) were NST. The ST-MS group had lower IJV flow than both HC and NST-MS groups. CONCLUSION After categorizing the MS population into two groups based upon anatomical stenosis, as determined from an absolute quantification of IJV cross section, clear differences in IJV flow between the ST-MS and HC samples became evident. Despite the unknown etiology of MS, abnormal venous flow was noted in a distinct group of MS patients compared to HC.
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Affiliation(s)
- Sean K Sethi
- MRI Institute of Biomedical Research, Detroit, Michigan
| | | | - Ana M Daugherty
- Institute of Gerontology and Department of Psychology, Wayne State University, Detroit, Michigan
| | - Wei Feng
- Department of Radiology, Wayne State University, Detroit, Michigan
| | | | - Naftali Raz
- Institute of Gerontology and Department of Psychology, Wayne State University, Detroit, Michigan
| | - E Mark Haacke
- MRI Institute of Biomedical Research, Detroit, Michigan
- Department of Radiology, Wayne State University, Detroit, Michigan
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16
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Chen D, Sharif B, Bi X, Wei J, Thomson LEJ, Bairey Merz CN, Berman DS, Li D. Quantification of myocardial blood flow using non-electrocardiogram-triggered MRI with three-slice coverage. Magn Reson Med 2015; 75:2112-20. [PMID: 26059326 DOI: 10.1002/mrm.25787] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 05/06/2015] [Accepted: 05/06/2015] [Indexed: 11/11/2022]
Abstract
PURPOSE Accurate quantification of myocardial perfusion is dependent on reliable electrocardiogram (ECG) triggering. Measuring myocardial blood flow (MBF) in patients with arrhythmias or poor ECGs is currently infeasible with MR. The purpose of this study was to demonstrate the feasibility of a non-ECG-triggered method with clinically useful three-slice ventricular coverage for measurement of MBF in healthy volunteers. METHODS A saturation recovery magnetization-prepared gradient recalled echo acquisition was continuously repeated during first-pass imaging. A slice-interleaved radial trajectory was employed to enable image-based retrospective triggering. The arterial input function was generated using a beat-by-beat T1 estimation method. The proposed technique was validated against a conventional ECG-triggered dual-bolus technique in 10 healthy volunteers. The technique was further demonstrated under adenosine stress in 12 healthy volunteers. RESULTS The proposed method produced MBF with no significant difference compared with the ECG-triggered technique. The proposed method yielded mean myocardial perfusion reserve comparable to published literature. CONCLUSION We have developed a non-ECG-triggered quantitative perfusion imaging method. In this preliminary study, our results demonstrate that our method yields comparable MBF compared with the conventional ECG-triggered method and that it is feasible for stress imaging.
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Affiliation(s)
- David Chen
- Department of Biomedical Engineering, Northwestern University, Chicago, Illinois, USA.,Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Behzad Sharif
- Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Xiaoming Bi
- MR R&D, Siemens Healthcare, Los Angeles, California, USA
| | - Janet Wei
- S. Mark Taper Foundation Imaging Center, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Louise E J Thomson
- S. Mark Taper Foundation Imaging Center, Cedars-Sinai Medical Center, Los Angeles, California, USA.,Barbara Streisand Women's Heart Center, Cedars-Sinai Heart Institute, Los Angeles, California, USA
| | - C Noel Bairey Merz
- Barbara Streisand Women's Heart Center, Cedars-Sinai Heart Institute, Los Angeles, California, USA
| | - Daniel S Berman
- Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA.,S. Mark Taper Foundation Imaging Center, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Debiao Li
- Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA.,David Geffen School of Medicine, University of California, Los Angeles, California, USA
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17
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Santelli C, Loecher M, Busch J, Wieben O, Schaeffter T, Kozerke S. Accelerating 4D flow MRI by exploiting vector field divergence regularization. Magn Reson Med 2015; 75:115-25. [PMID: 25684112 DOI: 10.1002/mrm.25563] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 11/12/2014] [Accepted: 11/12/2014] [Indexed: 11/10/2022]
Abstract
PURPOSE To improve velocity vector field reconstruction from undersampled four-dimensional (4D) flow MRI by penalizing divergence of the measured flow field. THEORY AND METHODS Iterative image reconstruction in which magnitude and phase are regularized separately in alternating iterations was implemented. The approach allows incorporating prior knowledge of the flow field being imaged. In the present work, velocity data were regularized to reduce divergence, using either divergence-free wavelets (DFW) or a finite difference (FD) method using the ℓ1-norm of divergence and curl. The reconstruction methods were tested on a numerical phantom and in vivo data. Results of the DFW and FD approaches were compared with data obtained with standard compressed sensing (CS) reconstruction. RESULTS Relative to standard CS, directional errors of vector fields and divergence were reduced by 55-60% and 38-48% for three- and six-fold undersampled data with the DFW and FD methods. Velocity vector displays of the numerical phantom and in vivo data were found to be improved upon DFW or FD reconstruction. CONCLUSION Regularization of vector field divergence in image reconstruction from undersampled 4D flow data is a valuable approach to improve reconstruction accuracy of velocity vector fields.
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Affiliation(s)
- Claudio Santelli
- Imaging Sciences and Biomedical Engineering, King's College London, United Kingdom.,Institute for Biomedical Engineering, University and ETH Zurich, Switzerland
| | - Michael Loecher
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Julia Busch
- Institute for Biomedical Engineering, University and ETH Zurich, Switzerland
| | - Oliver Wieben
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, USA.,Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Tobias Schaeffter
- Imaging Sciences and Biomedical Engineering, King's College London, United Kingdom
| | - Sebastian Kozerke
- Imaging Sciences and Biomedical Engineering, King's College London, United Kingdom.,Institute for Biomedical Engineering, University and ETH Zurich, Switzerland
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Shimada E, Zhu M, Kimura S, Streiff C, Houle H, Datta S, Sahn DJ, Ashraf M. Quantitative assessment of mitral inflow and aortic outflow stroke volumes by 3-dimensional real-time full-volume color flow doppler transthoracic echocardiography: an in vivo study. J Ultrasound Med 2015; 34:95-103. [PMID: 25542944 DOI: 10.7863/ultra.34.1.95] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
OBJECTIVES Noninvasive quantification of left ventricular (LV) stroke volumes has an important clinical role in assessing circulation and monitoring therapeutic interventions for cardiac disease. This study validated the accuracy of a real-time 3-dimensional (3D) color flow Doppler method performed during transthoracic echocardiography (TTE) for quantifying volume flows through the mitral and aortic valves using a dedicated offline 3D flow computation program compared to LV sonomicrometry in an open-chest animal model. METHODS Forty-six different hemodynamic states in 5 open-chest pigs were studied. Three-dimensional color flow Doppler TTE and 2-dimensional (2D) TTE were performed by epicardial scanning. The dedicated software was used to compute flow volumes at the mitral annulus and the left ventricular outflow tract (LVOT) with the 3D color flow Doppler method. Stroke volumes by 2D TTE were computed in the conventional manner. Stroke volumes derived from sonomicrometry were used as reference values. RESULTS Mitral inflow and LVOT outflow derived from the 3D color flow Doppler method correlated well with stroke volumes by sonomicrometry (R = 0.96 and 0.96, respectively), whereas correlation coefficients for mitral inflow and LVOT outflow computed by 2D TTE and stroke volumes by sonomicrometry were R = 0.84 and 0.86. Compared to 2D TTE, the 3D method showed a smaller bias and narrower limits of agreement in both mitral inflow (mean ± SD: 3D, 2.36 ± 2.86 mL; 2D, 10.22 ± 8.46 mL) and LVOT outflow (3D, 1.99 ± 2.95 mL; 2D, 4.12 ± 6.32 mL). CONCLUSIONS Real-time 3D color flow Doppler quantification is feasible and accurate for measurement of mitral inflow and LVOT outflow stroke volumes over a range of hemodynamic conditions.
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Affiliation(s)
- Eriko Shimada
- Oregon Health and Science University, Portland, Oregon USA (E.S., M.Z., S.K., C.S., D.J.S., M.A.); and Siemens Medical Solutions USA, Inc, Mountain View, California USA (H.H., S.D.)
| | - Meihua Zhu
- Oregon Health and Science University, Portland, Oregon USA (E.S., M.Z., S.K., C.S., D.J.S., M.A.); and Siemens Medical Solutions USA, Inc, Mountain View, California USA (H.H., S.D.)
| | - Sumito Kimura
- Oregon Health and Science University, Portland, Oregon USA (E.S., M.Z., S.K., C.S., D.J.S., M.A.); and Siemens Medical Solutions USA, Inc, Mountain View, California USA (H.H., S.D.)
| | - Cole Streiff
- Oregon Health and Science University, Portland, Oregon USA (E.S., M.Z., S.K., C.S., D.J.S., M.A.); and Siemens Medical Solutions USA, Inc, Mountain View, California USA (H.H., S.D.)
| | - Helene Houle
- Oregon Health and Science University, Portland, Oregon USA (E.S., M.Z., S.K., C.S., D.J.S., M.A.); and Siemens Medical Solutions USA, Inc, Mountain View, California USA (H.H., S.D.)
| | - Saurabh Datta
- Oregon Health and Science University, Portland, Oregon USA (E.S., M.Z., S.K., C.S., D.J.S., M.A.); and Siemens Medical Solutions USA, Inc, Mountain View, California USA (H.H., S.D.)
| | - David J Sahn
- Oregon Health and Science University, Portland, Oregon USA (E.S., M.Z., S.K., C.S., D.J.S., M.A.); and Siemens Medical Solutions USA, Inc, Mountain View, California USA (H.H., S.D.).
| | - Muhammad Ashraf
- Oregon Health and Science University, Portland, Oregon USA (E.S., M.Z., S.K., C.S., D.J.S., M.A.); and Siemens Medical Solutions USA, Inc, Mountain View, California USA (H.H., S.D.)
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Chen D, Sharif B, Dharmakumar R, Thomson LEJ, Bairey Merz CN, Berman DS, Li D. Quantification of myocardial blood flow using non-ECG-triggered MR imaging. Magn Reson Med 2014; 74:765-71. [PMID: 25227935 DOI: 10.1002/mrm.25451] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 08/19/2014] [Accepted: 08/22/2014] [Indexed: 12/11/2022]
Abstract
PURPOSE MR myocardial perfusion imaging is dependent on reliable electrocardiogram (ECG) triggering for accurate measurement of myocardial blood flow (MBF). A non-ECG-triggered method for quantitative first-pass imaging may improve clinical feasibility in patients with poor ECG signal. The purpose of this study is to evaluate the feasibility of a non-ECG-triggered method for myocardial perfusion imaging in a single slice. METHODS The proposed non-ECG-triggered technique uses a saturation-recovery magnetization preparation and golden-angle radial acquisition for integrated arterial input function (AIF) measurement. Image based self-gating with a temporal resolution of 42.6 ms is used to generate a first-pass image series with consistent cardiac phase. The AIF is measured using beat-by-beat T1 estimation of the ventricular blood pool. The proposed technique was performed on 14 healthy volunteers and compared against a conventional ECG-triggered dual-bolus acquisition. RESULTS The proposed method produced MBF with no significant difference compared with ECG-triggered technique (mean of 0.63 ± 0.22 mL/min/g to 0.73 ± 0.21 mL/min/g). CONCLUSION We have developed a non-ECG-triggered perfusion imaging method with T1 based measurement of the AIF in a single slice. In this preliminary study, our results demonstrate that MBF measured using the proposed method is comparable to the conventional ECG-triggered method.
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Affiliation(s)
- David Chen
- Department of Biomedical Engineering, Northwestern University, Chicago, Illinois, USA.,Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Behzad Sharif
- Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Rohan Dharmakumar
- Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA.,David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Louise E J Thomson
- S. Mark Taper Foundation Imaging Center, Department of Imaging, Cedars-Sinai Medical Center, Los Angeles, CA, USA.,Barbara Streisand Women's Heart Center, Cedars-Sinai Heart Institute, Los Angeles, California, USA
| | - C Noel Bairey Merz
- Barbara Streisand Women's Heart Center, Cedars-Sinai Heart Institute, Los Angeles, California, USA
| | - Daniel S Berman
- Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA.,S. Mark Taper Foundation Imaging Center, Department of Imaging, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Debiao Li
- Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA.,David Geffen School of Medicine, University of California, Los Angeles, California, USA
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20
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Giese D, Wong J, Greil GF, Buehrer M, Schaeffter T, Kozerke S. Towards highly accelerated Cartesian time-resolved 3D flow cardiovascular magnetic resonance in the clinical setting. J Cardiovasc Magn Reson 2014; 16:42. [PMID: 24942253 PMCID: PMC4230248 DOI: 10.1186/1532-429x-16-42] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 05/02/2014] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND The clinical applicability of time-resolved 3D flow cardiovascular magnetic resonance (CMR) remains compromised by the long scan times associated with phase-contrast imaging. The present work demonstrates the applicability of 8-fold acceleration of Cartesian time-resolved 3D flow CMR in 10 volunteers and in 9 patients with different congenital heart diseases (CHD). It is demonstrated that accelerated 3D flow CMR data acquisition and image reconstruction using k-t PCA (principal component analysis) can be implemented into clinical workflow and results are sufficiently accurate relative to conventional 2D flow CMR to permit for comprehensive flow quantification in CHD patients. METHODS The fidelity of k-t PCA was first investigated on retrospectively undersampled data for different acceleration factors and compared to k-t SENSE and fully sampled reference data. Subsequently, k-t PCA with 8-fold nominal undersampling was applied on 10 healthy volunteers and 9 CHD patients on a clinical 1.5 T MR scanner. Quantitative flow validation was performed in vessels of interest on the 3D flow datasets and compared to 2D through-plane flow acquisitions. Particle trace analysis was used to qualitatively visualise flow patterns in patients. RESULTS Accelerated time-resolved 3D flow data were successfully acquired in all subjects with 8-fold nominal scan acceleration. Nominal scan times excluding navigator efficiency were on the order of 6 min and 7 min in patients and volunteers. Mean differences in stroke volume in selected vessels of interest were 2.5 ± 8.4 ml and 1.63 ± 4.8 ml in volunteers and patients, respectively. Qualitative flow pattern analysis in the time-resolved 3D dataset revealed valuable insights into hemodynamics including circular and helical patterns as well as flow distributions and origin in the Fontan circulation. CONCLUSION Highly accelerated time-resolved 3D flow using k-t PCA is readily applicable in clinical routine protocols of CHD patients. Nominal scan times of 6 min are well tolerated and allow for quantitative and qualitative flow assessment in all great vessels.
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Affiliation(s)
- Daniel Giese
- Division of Imaging Sciences and Biomedical Engineering, King’s College London, London, UK
- Department of Radiology, University of Cologne, Cologne, Germany
| | - James Wong
- Division of Imaging Sciences and Biomedical Engineering, King’s College London, London, UK
| | - Gerald F Greil
- Division of Imaging Sciences and Biomedical Engineering, King’s College London, London, UK
| | - Martin Buehrer
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
| | - Tobias Schaeffter
- Division of Imaging Sciences and Biomedical Engineering, King’s College London, London, UK
| | - Sebastian Kozerke
- Division of Imaging Sciences and Biomedical Engineering, King’s College London, London, UK
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland
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Wang D, Shao J, Rapacchi S, Middione MJ, Ennis DB, Hu P. Phase contrast MRI with flow compensation view sharing. Magn Reson Med 2014; 73:505-13. [PMID: 24532480 DOI: 10.1002/mrm.25133] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 12/10/2013] [Accepted: 12/23/2013] [Indexed: 11/11/2022]
Abstract
PURPOSE To develop and evaluate a technique for accelerating phase contrast MRI (PC-MRI) acquisitions without significant compromise in flow quantification accuracy. METHODS PC-MRI is commonly acquired using interleaved flow-compensated (FC) and flow-encoded (FE) echoes. We hypothesized that FC data, which represent background phase, do not change significantly over time. Therefore, we proposed to undersample the FC data and use an FC view sharing (FCVS) approach to synthesize a composite FC frame for each corresponding FE frame. FCVS was evaluated in a flow phantom and healthy volunteers and compared with a standard FC/FE PC-MRI. RESULTS The FCVS sequence resulted in an error of 0.0% for forward flow and 2.0% for reverse flow volume when compared with FC/FE PC-MRI in a flow phantom. Measurements in the common carotid arteries showed that the FCVS method had -1.16 cm/s bias for maximum peak velocity and -0.019 mL bias in total flow, when compared with FC/FE with the same temporal resolution, but double the total acquisition time. These results represent ≤1.3% bias error in velocity and volumetric flow quantification. CONCLUSION FCVS can accelerate PC-MRI acquisitions while maintaining flow and velocity measurement accuracy when there is limited temporal variation in the FC data.
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Affiliation(s)
- Da Wang
- Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA; Biomedical Physics Interdepartmental Graduate Program, University of California, Los Angeles, Los Angeles, California, USA
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Kimura S, Streiff C, Zhu M, Shimada E, Datta S, Ashraf M, Sahn DJ. Evaluation of a new 3-dimensional color Doppler flow method to quantify flow across the mitral valve and in the left ventricular outflow tract: an in vitro study. J Ultrasound Med 2014; 33:265-271. [PMID: 24449729 DOI: 10.7863/ultra.33.2.265] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
OBJECTIVES The aim of this study was to assess the accuracy, feasibility, and reproducibility of determining stroke volume from a novel 3-dimensional (3D) color Doppler flow quantification method for mitral valve (MV) inflow and left ventricular outflow tract (LVOT) outflow at different stroke volumes when compared with the actual flow rate in a pumped porcine cardiac model. METHODS Thirteen freshly harvested pig hearts were studied in a water tank. We inserted a latex balloon into each left ventricle from the MV annulus to the LVOT, which were passively pumped at different stroke volumes (30-80 mL) using a calibrated piston pump at increments of 10 mL. Four-dimensional flow volumes were obtained without electrocardiographic gating. The digital imaging data were analyzed offline using prototype software. Two hemispheric flow-sampling planes for color Doppler velocity measurements were placed at the MV annulus and LVOT. The software computed the flow volumes at the MV annulus and LVOT within the user-defined volume and cardiac cycle. RESULTS This novel 3D Doppler flow quantification method detected incremental increases in MV inflow and LVOT outflow in close agreement with pumped stroke volumes (MV inflow, r = 0.96; LVOT outflow, r = 0.96; P < .01). Bland-Altman analysis demonstrated overestimation of both (MV inflow, 5.42 mL; LVOT outflow, 4.46 mL) with 95% of points within 95% limits of agreement. Interobserver variability values showed good agreement for all stroke volumes at both the MV annulus and LVOT. CONCLUSIONS This study has shown that the 3D color Doppler flow quantification method we used is able to compute stroke volumes accurately at the MV annulus and LVOT in the same cardiac cycle without electrocardiographic gating. This method may be valuable for assessment of cardiac output in clinical studies.
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Affiliation(s)
- Sumito Kimura
- Department of Pediatric Cardiology, Oregon Health and Science University, 3181 SW Sam Jackson Park Dr, L608, Portland, OR 97239-3098 USA.
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Mut F, Ruijters D, Babic D, Bleise C, Lylyk P, Cebral JR. Effects of changing physiologic conditions on the in vivo quantification of hemodynamic variables in cerebral aneurysms treated with flow diverting devices. Int J Numer Method Biomed Eng 2014; 30:135-142. [PMID: 24039143 DOI: 10.1002/cnm.2594] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 06/24/2013] [Accepted: 08/14/2013] [Indexed: 05/29/2023]
Abstract
Quantifying the hemodynamic environment within aneurysms and its change after deployment of flow diverting devices is important to assess the device efficacy and understand their long-term effects. The purpose of this study was to estimate deviations in the quantification of the relative change of hemodynamic variables during flow diversion treatment of cerebral aneurysms due to changing physiologic flow conditions. Computational fluid dynamics calculations were carried out on three patient-specific geometries. Three flow diverters were virtually implanted in each geometry and simulations were performed under five pulsatile flow conditions. Hemodynamic variables including aneurysm inflow rate, mean velocity, shear rate, and wall shear stress were quantified before and after stenting. Deviations in the relative change of these variables due to varying flow conditions were calculated. The results indicate that a change in the mean flow of the parent artery of approximately 30-50% can induce large deviations in the relative change of hemodynamic variables in the range of 30-80%. Thus, quantification of hemodynamic changes during flow diversion must be carried out carefully. Variations in the inflow conditions during the procedure may induce large deviations in the quantification of these changes.
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Affiliation(s)
- Fernando Mut
- Center for Computational Fluid Dynamics, George Mason University, Fairfax, VA, USA
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Fluckiger JU, Goldberger JJ, Lee DC, Ng J, Lee R, Goyal A, Markl M. Left atrial flow velocity distribution and flow coherence using four-dimensional FLOW MRI: a pilot study investigating the impact of age and Pre- and Postintervention atrial fibrillation on atrial hemodynamics. J Magn Reson Imaging 2013; 38:580-7. [PMID: 23292793 DOI: 10.1002/jmri.23994] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Accepted: 11/19/2012] [Indexed: 11/11/2022] Open
Abstract
PURPOSE To use four-dimensional (4D) flow MRI to characterize and quantify 3D blood flow in the left atria (LA) of patients with a history of atrial fibrillation (AF). MATERIALS AND METHODS The 4D flow MRI was acquired in 19 volunteers (n = 9<30 years, n = 10>50 years) and 10 patients with AF (62 ± 9.6 years; n = 4 in persistent AF, n = 6 postintervention). The LA in each dataset was segmented, and intra-atrial blood flow velocity was quantified. Flow coherence was measured as the consistency of the net blood flow vector. RESULTS Quantification of atrial flow revealed significant differences in atrial hemodynamics between age groups. Postintervention AF patients had a mean blood flow of 0.22 ± 0.04 m/s, which was not significantly different than age-matched volunteers (0.21 ± 0.03 m/s). Patients with persistent AF had a mean blood flow of 0.13 ± 0.01 m/s, lower than AF patients in sinus rhythm (0.22 ± 0.04 m/s, P = 0.005), or age-matched volunteers (0.21 ± 0.03 m/s, P < 0.001). Flow coherence was significantly impaired in patients in AF. CONCLUSION Flow-sensitive MRI shows that patients with a history of AF had global hemodynamics in the LA similar to those of age-matched volunteers. Additional studies with larger cohorts of AF patients and correlation with outcome are needed to further investigate the potential of atrial 4D flow MRI to flow patterns indicative of stroke risk in AF.
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Affiliation(s)
- Jacob U Fluckiger
- Department of Radiology, Northwestern Memorial Hospital, Chicago, Illinois, USA.
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Bürk J, Blanke P, Stankovic Z, Barker A, Russe M, Geiger J, Frydrychowicz A, Langer M, Markl M. Evaluation of 3D blood flow patterns and wall shear stress in the normal and dilated thoracic aorta using flow-sensitive 4D CMR. J Cardiovasc Magn Reson 2012; 14:84. [PMID: 23237187 PMCID: PMC3534249 DOI: 10.1186/1532-429x-14-84] [Citation(s) in RCA: 147] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Accepted: 11/28/2012] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The purpose of this study was to investigate 3D flow patterns and vessel wall parameters in patients with dilated ascending aorta, age-matched subjects, and healthy volunteers. METHODS Thoracic time-resolved 3D phase contrast CMR with 3-directional velocity encoding was applied to 33 patients with dilated ascending aorta (diameter≥40 mm, age=60±16 years), 15 age-matched normal controls (diameter≤37 mm, age=68±7.5 years) and 15 young healthy volunteers (diameter≤30 mm, age=23±2 years). 3D blood flow was visualized and flow patterns were graded regarding presence of supra-physiologic-helix and vortex flow using a semi-quantitative 3-point grading scale. Blood flow velocities, regional wall shear stress (WSS), and oscillatory shear index (OSI) were quantified. RESULTS Incidence and strength of supra-physiologic-helix and vortex flow in the ascending aorta (AAo) was significantly higher in patients with dilated AAo (16/33 and 31/33, grade 0.9±1.0 and 1.5±0.6) than in controls (2/15 and 7/15, grade 0.2±0.6 and 0.6±0.7, P<.05) or healthy volunteers (1/15 and 0/15, grade 0.1±0.3 P<.05). Greater strength of the ascending aortic helix and vortex flow were associated with significant differences in AAo diameters (P<.05). Peak systolic WSS in the ascending aorta and aortic arch was significantly lower in patients with dilated AAo (P<.0157-.0488). AAo diameter positively correlated to time to peak systolic velocities (r=0.30-0.53, P<.04), OSI (r=0.33-0.49, P<0.02) and inversely correlated to peak systolic WSS (r=0.32-0.40, P<.03). Peak systolic WSS was significantly lower in AAo aneurysms at the right and outer curvature within the AAo and proximal arch (P<.01-.05). CONCLUSIONS Increase in AAo diameter is significantly correlated with the presence and strength of supra-physiologic-helix and vortex formation in the AAo, as well with decrease in systolic WSS and increase in OSI.
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Affiliation(s)
- Jonas Bürk
- Department of Diagnostic Radiology, Medical Physics, University Hospital, Freiburg, Germany
| | - Philipp Blanke
- Department of Diagnostic Radiology, Medical Physics, University Hospital, Freiburg, Germany
| | - Zoran Stankovic
- Department of Diagnostic Radiology, Medical Physics, University Hospital, Freiburg, Germany
- Departments of Radiology and Biomedical Engineering, Northwestern University, Chicago, IL, USA
| | - Alex Barker
- Department of Diagnostic Radiology, Medical Physics, University Hospital, Freiburg, Germany
- Departments of Radiology and Biomedical Engineering, Northwestern University, Chicago, IL, USA
| | - Maximilian Russe
- Department of Diagnostic Radiology, Medical Physics, University Hospital, Freiburg, Germany
| | - Julia Geiger
- Department of Diagnostic Radiology, Medical Physics, University Hospital, Freiburg, Germany
| | - Alex Frydrychowicz
- Clinic of Radiology and Nuclear Medicine, University Hospital of Schleswig-Holstein, Campus, Lübeck, Germany
| | - Mathias Langer
- Department of Diagnostic Radiology, Medical Physics, University Hospital, Freiburg, Germany
| | - Michael Markl
- Department of Diagnostic Radiology, Medical Physics, University Hospital, Freiburg, Germany
- Departments of Radiology and Biomedical Engineering, Northwestern University, Chicago, IL, USA
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Abstract
Cardiovascular magnetic resonance (CMR) has become a valuable investigative tool in many areas of cardiac medicine. Its value in heart valve disease is less well appreciated however, particularly as echocardiography is a powerful and widely available technique in valve disease. This review highlights the added value that CMR can bring in valve disease, complementing echocardiography in many areas, but it has also become the first-line investigation in some, such as pulmonary valve disease and assessing the right ventricle. CMR has many advantages, including the ability to image in any plane, which allows full visualisation of valves and their inflow/outflow tracts, direct measurement of valve area (particularly for stenotic valves), and characterisation of the associated great vessel anatomy (e.g. the aortic root and arch in aortic valve disease). A particular strength is the ability to quantify flow, which allows accurate measurement of regurgitation, cardiac shunt volumes/ratios and differential flow volumes (e.g. left and right pulmonary arteries). Quantification of ventricular volumes and mass is vital for determining the impact of valve disease on the heart, and CMR is the 'Gold standard' for this. Limitations of the technique include partial volume effects due to image slice thickness, and a low ability to identify small, highly mobile objects (such as vegetations) due to the need to acquire images over several cardiac cycles. The review examines the advantages and disadvantages of each imaging aspect in detail, and considers how CMR can be used optimally for each valve lesion.
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Westenberg JJM, Doornbos J, Bax JJ, Danilouchkine MG, van der Geest RJ, Labadie G, Lamb HJ, Versteegh MIM, de Roos A, Dion RAE, Reiber JHC. Mitral valve regurgitation: accurate blood flow quantification with MRI. Neth Heart J 2004; 12:382-388. [PMID: 25696368 PMCID: PMC2497179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023] Open
Abstract
BACKGROUND The quantification of transvalvular blood flow through the mitral valve (MV) and regurgitant flow in particular is difficult with echocardiography, which is the method of choice to diagnose patients selected for valve repair or replacement. With magnetic resonance imaging, information on the intraventricular blood flow can be obtained. Several scanning techniques have attempted to assess the regurgitant flow. These techniques either do not directly assess the complete flow through the MV, or they do not measure the flow at the location of the valve. AIM To investigate the accuracy of a novel method using three-directional velocity-encoded MRI to acquire the transvalvular blood flow directly from the intraventricular blood flow field, also representing the regurgitant flow during systole. METHODS Ten volunteers without cardiac valvular disease were recruited. The transvalvular MV flow volume was measured with three-directional velocity-encoded MRI (3-dir MV flow). RESULTS The transvalvular flow measurements correlate very well with the flow measured in the aorta (rp=0.92, p<0.01). The small differences (mean -5±7 ml) are insignificant (p=0.06) and demonstrate the high accuracy of the new method. Intra- and inter-observer studies showed non-significant mean differences of 0.9±5.1 ml and 1.3±5.6 ml, respectively, thereby proving the high reproducibility. CONCLUSION Three-directional velocity-encoded MRI is a patient-friendly and easy-to-use method suitable for quantifying the regurgitant MV flow in clinical practice.
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