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Srinivas S, Masutani E, Norbash A, Hsiao A. Deep learning phase error correction for cerebrovascular 4D flow MRI. Sci Rep 2023; 13:9095. [PMID: 37277401 DOI: 10.1038/s41598-023-36061-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 05/29/2023] [Indexed: 06/07/2023] Open
Abstract
Background phase errors in 4D Flow MRI may negatively impact blood flow quantification. In this study, we assessed their impact on cerebrovascular flow volume measurements, evaluated the benefit of manual image-based correction, and assessed the potential of a convolutional neural network (CNN), a form of deep learning, to directly infer the correction vector field. With IRB waiver of informed consent, we retrospectively identified 96 MRI exams from 48 patients who underwent cerebrovascular 4D Flow MRI from October 2015 to 2020. Flow measurements of the anterior, posterior, and venous circulation were performed to assess inflow-outflow error and the benefit of manual image-based phase error correction. A CNN was then trained to directly infer the phase-error correction field, without segmentation, from 4D Flow volumes to automate correction, reserving from 23 exams for testing. Statistical analyses included Spearman correlation, Bland-Altman, Wilcoxon-signed rank (WSR) and F-tests. Prior to correction, there was strong correlation between inflow and outflow (ρ = 0.833-0.947) measurements with the largest discrepancy in the venous circulation. Manual phase error correction improved inflow-outflow correlation (ρ = 0.945-0.981) and decreased variance (p < 0.001, F-test). Fully automated CNN correction was non-inferior to manual correction with no significant differences in correlation (ρ = 0.971 vs ρ = 0.982) or bias (p = 0.82, Wilcoxon-Signed Rank test) of inflow and outflow measurements. Residual background phase error can impair inflow-outflow consistency of cerebrovascular flow volume measurements. A CNN can be used to directly infer the phase-error vector field to fully automate phase error correction.
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Affiliation(s)
- Shanmukha Srinivas
- Department of Radiology, University of California San Diego, 200 West Arbor Drive, San Diego, CA, 92103, USA
- Department of Radiology, University of California Los Angeles, 757 Westwood Plaza, Los Angeles, CA, 90095, USA
| | - Evan Masutani
- Department of Radiology, University of California San Diego, 200 West Arbor Drive, San Diego, CA, 92103, USA
| | - Alexander Norbash
- Department of Radiology, University of California San Diego, 200 West Arbor Drive, San Diego, CA, 92103, USA
| | - Albert Hsiao
- Department of Radiology, University of California San Diego, 200 West Arbor Drive, San Diego, CA, 92103, USA.
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2
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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] [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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3
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Yavuz Ilik S, Otani T, Yamada S, Watanabe Y, Wada S. A subject-specific assessment of measurement errors and their correction in cerebrospinal fluid velocity maps using 4D flow MRI. Magn Reson Med 2021; 87:2412-2423. [PMID: 34866235 DOI: 10.1002/mrm.29111] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 11/17/2021] [Accepted: 11/17/2021] [Indexed: 11/05/2022]
Abstract
PURPOSE Phase-contrast MRI (PC-MRI) of cerebrospinal fluid (CSF) velocity is used to evaluate the characteristics of intracranial diseases, such as normal-pressure hydrocephalus (NPH). Nevertheless, PC-MRI has several potential error sources, with eddy-current-based phase offset error being non-negligible in CSF measurement. In this study, we assess the measurement error of CSF velocity maps obtained using 4D flow MRI and evaluate correction methods. METHODS CSF velocity maps of 10 patients with NPH were acquired using 4D flow MRI (velocity-encoding = 5 cm/s). Distributed phase offset error was estimated for a whole 3D background field by polynomial fitting using robust regression analysis. This estimated phase offset error was then used to correct the CSF velocity maps. The estimated error profiles were compared with those obtained using an existing 2D correction approach involving local background information near the region of interest. RESULTS The residual standard error of the polynomial fitting against the phase offset error extracted from the measured velocities was within 0.2 cm/s. The spatial dependencies of the phase offset errors showed similar tendencies in all cases, but sufficient differences in these values were found to indicate requirement of velocity correction. Differences of the estimated errors among other correction approaches were in the order of 10-2 cm/s, and the estimated errors were in good agreement with those obtained using existing approaches. CONCLUSION Our method is capable of estimating the measurement error of CSF velocity maps obtained from 4D flow MRI and provides quantitatively reasonable characteristics for the main CSF profile in the cerebral aqueduct in patients with NPH.
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Affiliation(s)
- Selin Yavuz Ilik
- Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan
| | - Tomohiro Otani
- Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan
| | - Shigeki Yamada
- Department of Neurosurgery, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Yoshiyuki Watanabe
- Department of Radiology, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Shigeo Wada
- Department of Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan
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Lagerstrand KM, Svensson F, Polte CL, Bech-Hanssen O, Starck G, Chadorowski A, Johnsson ÅA. Reliable phase-contrast flow volume magnetic resonance measurements are feasible without adjustment of the velocity encoding parameter. J Med Imaging (Bellingham) 2020; 7:063502. [PMID: 33313339 DOI: 10.1117/1.jmi.7.6.063502] [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: 04/14/2020] [Accepted: 11/23/2020] [Indexed: 11/14/2022] Open
Abstract
Purpose: To show that adjustment of velocity encoding (VENC) for phase-contrast (PC) flow volume measurements is not necessary in modern MR scanners with effective background velocity offset corrections. Approach: The independence on VENC was demonstrated theoretically, but also experimentally on dedicated phantoms and on patients with chronic aortic regurgitation ( n = 17 ) and one healthy volunteer. All PC measurements were performed using a modern MR scanner, where the pre-emphasis circuit but also a subsequent post-processing filter were used for effective correction of background velocity offset errors. Results: The VENC level strongly affected the velocity noise level in the PC images and, hence, the estimated peak flow velocity. However, neither the regurgitant blood flow volume nor the mean flow velocity displayed any clinically relevant dependency on the VENC level. Also, the background velocity offset was shown to be close to zero ( < 0.6 cm / s ) for a VENC range of 150 to 500 cm / s , adding no significant errors to the PC flow volume measurement. Conclusions: Our study shows that reliable PC flow volume measurements are feasible without adjustment of the VENC parameter. Without the need for VENC adjustments, the scan time can be reduced for the benefit of the patient.
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Affiliation(s)
- Kerstin M Lagerstrand
- The Sahlgrenska Academy, University of Gothenburg, Institute of Clinical Sciences, Sweden.,Sahlgrenska University Hospital, Department of Medical Physics and Biomedical Engineering, Gothenburg, Sweden
| | - Frida Svensson
- The Sahlgrenska Academy, University of Gothenburg, Institute of Clinical Sciences, Sweden.,Sahlgrenska University Hospital, Department of Medical Physics and Biomedical Engineering, Gothenburg, Sweden
| | - Christian L Polte
- The Sahlgrenska Academy, University of Gothenburg, Institute of Medicine, Sweden.,Sahlgrenska University Hospital, Department of Clinical Physiology, Gothenburg, Sweden
| | - Odd Bech-Hanssen
- The Sahlgrenska Academy, University of Gothenburg, Institute of Medicine, Sweden.,Sahlgrenska University Hospital, Department of Clinical Physiology, Gothenburg, Sweden
| | - Göran Starck
- The Sahlgrenska Academy, University of Gothenburg, Institute of Clinical Sciences, Sweden.,Sahlgrenska University Hospital, Department of Medical Physics and Biomedical Engineering, Gothenburg, Sweden
| | - Artur Chadorowski
- Chalmers University of Technology, Department of Electrical Engineering, Gothenburg, Sweden
| | - Åse A Johnsson
- The Sahlgrenska Academy, University of Gothenburg, Institute of Clinical Sciences, Sweden.,Sahlgrenska University Hospital, Department of Radiology, Gothenburg, Sweden
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Minderhoud SCS, van der Velde N, Wentzel JJ, van der Geest RJ, Attrach M, Wielopolski PA, Budde RPJ, Helbing WA, Roos-Hesselink JW, Hirsch A. The clinical impact of phase offset errors and different correction methods in cardiovascular magnetic resonance phase contrast imaging: a multi-scanner study. J Cardiovasc Magn Reson 2020; 22:68. [PMID: 32938483 PMCID: PMC7495876 DOI: 10.1186/s12968-020-00659-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 08/06/2020] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Cardiovascular magnetic resonance (CMR) phase contrast (PC) flow measurements suffer from phase offset errors. Background subtraction based on stationary phantom measurements can most reliably be used to overcome this inaccuracy. Stationary tissue correction is an alternative and does not require additional phantom scanning. The aim of this study was 1) to compare measurements with and without stationary tissue correction to phantom corrected measurements on different GE Healthcare CMR scanners using different software packages and 2) to evaluate the clinical implications of these methods. METHODS CMR PC imaging of both the aortic and pulmonary artery flow was performed in patients on three different 1.5 T CMR scanners (GE Healthcare) using identical scan parameters. Uncorrected, first, second and third order stationary tissue corrected flow measurement were compared to phantom corrected flow measurements, our reference method, using Medis QFlow, Circle cvi42 and MASS software. The optimal (optimized) stationary tissue order was determined per scanner and software program. Velocity offsets, net flow, clinically significant difference (deviation > 10% net flow), and regurgitation severity were assessed. RESULTS Data from 175 patients (28 (17-38) years) were included, of which 84% had congenital heart disease. First, second and third order and optimized stationary tissue correction did not improve the velocity offsets and net flow measurements. Uncorrected measurements resulted in the least clinically significant differences in net flow compared to phantom corrected data. Optimized stationary tissue correction per scanner and software program resulted in net flow differences (> 10%) in 19% (MASS) and 30% (Circle cvi42) of all measurements compared to 18% (MASS) and 23% (Circle cvi42) with no correction. Compared to phantom correction, regurgitation reclassification was the least common using uncorrected data. One CMR scanner performed worse and significant net flow differences of > 10% were present both with and without stationary tissue correction in more than 30% of all measurements. CONCLUSION Phase offset errors had a significant impact on net flow quantification, regurgitation assessment and varied greatly between CMR scanners. Background phase correction using stationary tissue correction worsened accuracy compared to no correction on three GE Healthcare CMR scanners. Therefore, careful assessment of phase offset errors at each individual scanner is essential to determine whether routine use of phantom correction is necessary. TRIAL REGISTRATION Observational Study.
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Affiliation(s)
- Savine C. S. Minderhoud
- Department of Cardiology, Erasmus Medical Center, University Medical Center Rotterdam, P.O. Box 2040, Room Rg-419, Rotterdam, 3000 CA the Netherlands
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Nikki van der Velde
- Department of Cardiology, Erasmus Medical Center, University Medical Center Rotterdam, P.O. Box 2040, Room Rg-419, Rotterdam, 3000 CA the Netherlands
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Jolanda J. Wentzel
- Department of Cardiology, Erasmus Medical Center, University Medical Center Rotterdam, P.O. Box 2040, Room Rg-419, Rotterdam, 3000 CA the Netherlands
| | - Rob J. van der Geest
- Department of Radiology, Division of Image Processing, Leiden University Medical Center, Leiden, The Netherlands
| | - Mohammed Attrach
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Piotr A. Wielopolski
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Ricardo P. J. Budde
- Department of Cardiology, Erasmus Medical Center, University Medical Center Rotterdam, P.O. Box 2040, Room Rg-419, Rotterdam, 3000 CA the Netherlands
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Willem A. Helbing
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
- Division of Pediatric Cardiology, Department of Pediatrics, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Jolien W. Roos-Hesselink
- Department of Cardiology, Erasmus Medical Center, University Medical Center Rotterdam, P.O. Box 2040, Room Rg-419, Rotterdam, 3000 CA the Netherlands
| | - Alexander Hirsch
- Department of Cardiology, Erasmus Medical Center, University Medical Center Rotterdam, P.O. Box 2040, Room Rg-419, Rotterdam, 3000 CA the Netherlands
- Department of Radiology and Nuclear Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
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6
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Paul EA, Solana AB, Duong J, Shah AM, Lai WW, Tan ET, Hardy CJ, Chelliah A. Evaluation of self-calibrated non-linear phase-contrast correction in pediatric and congenital cardiovascular magnetic resonance imaging. Pediatr Radiol 2020; 50:656-663. [PMID: 32047987 DOI: 10.1007/s00247-020-04623-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 11/10/2019] [Accepted: 01/21/2020] [Indexed: 11/25/2022]
Abstract
BACKGROUND The need for background error correction in phase-contrast flow analysis has historically posed a challenge in cardiac magnetic resonance (MR) imaging. While previous studies have shown that phantom correction improves flow measurements, it impedes scanner workflow. OBJECTIVE To evaluate the efficacy of self-calibrated non-linear phase-contrast correction on flows in pediatric and congenital cardiac MR compared to phantom correction as the standard. MATERIALS AND METHODS We retrospectively identified children who had great-vessel phase-contrast and static phantom sequences acquired between January 2015 and June 2015. We applied a novel correction method to each phase-contrast sequence post hoc. Uncorrected, non-linear, and phantom-corrected flows were compared using intraclass correlation. We used paired t-tests to compare how closely non-linear and uncorrected flows approximated phantom-corrected flows. In children without intra- or extracardiac shunts or significant semilunar valvular regurgitation, we used paired t-tests to compare how closely the uncorrected pulmonary-to-systemic flow ratio (Qp:Qs) and non-linear Qp:Qs approximated phantom-corrected Qp:Qs. RESULTS We included 211 diagnostic-quality phase-contrast sequences (93 aorta, 74 main pulmonary artery [MPA], 21 left pulmonary artery [LPA], 23 right pulmonary artery [RPA]) from 108 children (median age 15 years, interquartile range 11-18 years). Intraclass correlation showed strong agreement between non-linear and phantom-corrected flow measurements but also between uncorrected and phantom-corrected flow measurements. Non-linear flow measurements did not more closely approximate phantom-corrected measurements than did uncorrected measurements for any vessel. In 39 children without significant shunting or regurgitation, mean non-linear Qp:Qs (1.07; 95% confidence interval [CI] = 1.01, 1.13) was no closer than mean uncorrected Qp:Qs (1.06; 95% CI = 1.00, 1.13) to mean phantom-corrected Qp:Qs (1.02; 95% CI = 0.98, 1.06). CONCLUSION Despite strong agreement between self-calibrated non-linear and phantom correction, cardiac flows and shunt calculations with non-linear correction were no closer to phantom-corrected measurements than those without background correction. However, phantom-corrected flows also demonstrated minimal differences from uncorrected flows. These findings suggest that in the current era, more accurate phase-contrast flow measurements might limit the need for background correction. Further investigation of the clinical impact and optimal methods of background correction in the pediatric and congenital cardiac population is needed.
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Affiliation(s)
- Erin A Paul
- Division of Pediatric Cardiology, Department of Pediatrics, New York-Presbyterian Morgan Stanley Children's Hospital, Columbia University Medical Center, 3959 Broadway, New York, NY, 10032, USA.
| | | | - Jimmy Duong
- Department of Biostatistics, Mailman School of Public Health, Columbia University Medical Center, New York, NY, USA
| | - Amee M Shah
- Division of Pediatric Cardiology, Department of Pediatrics, New York-Presbyterian Morgan Stanley Children's Hospital, Columbia University Medical Center, 3959 Broadway, New York, NY, 10032, USA
| | - Wyman W Lai
- Department of Pediatric Cardiology, Children's Hospital of Orange County, Orange, CA, USA
| | - Ek T Tan
- GE Global Research, Niskayuna, NY, USA
| | | | - Anjali Chelliah
- Division of Pediatric Cardiology, Department of Pediatrics, New York-Presbyterian Morgan Stanley Children's Hospital, Columbia University Medical Center, 3959 Broadway, New York, NY, 10032, USA
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Keenan KE, Biller JR, Delfino JG, Boss MA, Does MD, Evelhoch JL, Griswold MA, Gunter JL, Hinks RS, Hoffman SW, Kim G, Lattanzi R, Li X, Marinelli L, Metzger GJ, Mukherjee P, Nordstrom RJ, Peskin AP, Perez E, Russek SE, Sahiner B, Serkova N, Shukla-Dave A, Steckner M, Stupic KF, Wilmes LJ, Wu HH, Zhang H, Jackson EF, Sullivan DC. Recommendations towards standards for quantitative MRI (qMRI) and outstanding needs. J Magn Reson Imaging 2019; 49:e26-e39. [PMID: 30680836 PMCID: PMC6663309 DOI: 10.1002/jmri.26598] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 11/16/2018] [Accepted: 11/16/2018] [Indexed: 12/12/2022] Open
Abstract
LEVEL OF EVIDENCE 5 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2019.
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Affiliation(s)
- Kathryn E Keenan
- Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, Colorado, USA
| | - Joshua R Biller
- Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, Colorado, USA
| | - Jana G Delfino
- Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, Maryland, USA
| | - Michael A Boss
- Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, Colorado, USA
- Department of Physics, University of Colorado, Boulder, Colorado, USA
| | - Mark D Does
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA
| | | | - Mark A Griswold
- Department of Radiology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Jeffrey L Gunter
- Departments of Radiology and Information Technology, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Stuart W Hoffman
- Rehabilitation Research and Development Service, Department of Veterans Affairs, Washington, DC, USA
| | - Geena Kim
- College of Computer & Information Sciences, Regis University, Denver, Colorado, USA
| | - Riccardo Lattanzi
- Department of Radiology, New York University School of Medicine, New York, New York, USA
| | - Xiaojuan Li
- Program of Advanced Musculoskeletal Imaging (PAMI), Cleveland Clinic, Cleveland, Ohio, USA
| | | | - Gregory J Metzger
- Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Pratik Mukherjee
- Department of Radiology, University of California San Francisco, San Francisco, California, USA
| | | | - Adele P Peskin
- Information Technology Laboratory, National Institute of Standards and Technology, Boulder, Colorado, USA
| | | | - Stephen E Russek
- Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, Colorado, USA
| | - Berkman Sahiner
- Center for Devices and Radiological Health, Food and Drug Administration, Silver Spring, Maryland, USA
| | - Natalie Serkova
- Department of Radiology, Anschutz Medical Center, Aurora, Colorado, USA
| | - Amita Shukla-Dave
- Departments of Medical Physics and Radiology, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | | | - Karl F Stupic
- Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, Colorado, USA
| | - Lisa J Wilmes
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Holden H Wu
- Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | | | - Edward F Jackson
- Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Daniel C Sullivan
- Department of Radiology, Duke University Medical Center, Durham, North Carolina, USA
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Hofman MBM, Rodenburg MJA, Markenroth Bloch K, Werner B, Westenberg JJM, Valsangiacomo Buechel ER, Nijveldt R, Spruijt OA, Kilner PJ, van Rossum AC, Gatehouse PD. In-vivo validation of interpolation-based phase offset correction in cardiovascular magnetic resonance flow quantification: a multi-vendor, multi-center study. J Cardiovasc Magn Reson 2019; 21:30. [PMID: 31104632 PMCID: PMC6526620 DOI: 10.1186/s12968-019-0538-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 04/03/2019] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND A velocity offset error in phase contrast cardiovascular magnetic resonance (CMR) imaging is a known problem in clinical assessment of flow volumes in vessels around the heart. Earlier studies have shown that this offset error is clinically relevant over different systems, and cannot be removed by protocol optimization. Correction methods using phantom measurements are time consuming, and assume reproducibility of the offsets which is not the case for all systems. An alternative previously published solution is to correct the in-vivo data in post-processing, interpolating the velocity offset from stationary tissue within the field-of-view. This study aims to validate this interpolation-based offset correction in-vivo in a multi-vendor, multi-center setup. METHODS Data from six 1.5 T CMR systems were evaluated, with two systems from each of the three main vendors. At each system aortic and main pulmonary artery 2D flow studies were acquired during routine clinical or research examinations, with an additional phantom measurement using identical acquisition parameters. To verify the phantom acquisition, a region-of-interest (ROI) at stationary tissue in the thorax wall was placed and compared between in-vivo and phantom measurements. Interpolation-based offset correction was performed on the in-vivo data, after manually excluding regions of spatial wraparound. Correction performance of different spatial orders of interpolation planes was evaluated. RESULTS A total of 126 flow measurements in 82 subjects were included. At the thorax wall the agreement between in-vivo and phantom was - 0.2 ± 0.6 cm/s. Twenty-eight studies were excluded because of a difference at the thorax wall exceeding 0.6 cm/s from the phantom scan, leaving 98. Before correction, the offset at the vessel as assessed in the phantom was - 0.4 ± 1.5 cm/s, which resulted in a - 5 ± 16% error in cardiac output. The optimal order of the interpolation correction plane was 1st order, except for one system at which a 2nd order plane was required. Application of the interpolation-based correction revealed a remaining offset velocity of 0.1 ± 0.5 cm/s and 0 ± 5% error in cardiac output. CONCLUSIONS This study shows that interpolation-based offset correction reduces the offset with comparable efficacy as phantom measurement phase offset correction, without the time penalty imposed by phantom scans. TRIAL REGISTRATION The study was registered in The Netherlands National Trial Register (NTR) under TC 4865 . Registered 19 September 2014. Retrospectively registered.
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Affiliation(s)
- Mark B. M. Hofman
- Radiology and Nuclear Medicine, ICaR-VU, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam, the Netherlands
| | - Manouk J. A. Rodenburg
- Radiology and Nuclear Medicine, ICaR-VU, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam, the Netherlands
| | - Karin Markenroth Bloch
- Lund University Bioimaging Center, Lund University, SE-221 85 Lund, Sweden
- Philips Healthcare, SE-164 85 Stockholm, Sweden
| | - Beat Werner
- Department Diagnostic Imaging, University Children’s Hospital, Steinwiesstrasse 75, 8032 Zürich, Switzerland
| | - Jos J. M. Westenberg
- Radiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, the Netherlands
| | | | - Robin Nijveldt
- Cardiology, ICaR-VU, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam, the Netherlands
| | - Onno A. Spruijt
- Pulmonology, ICaR-VU, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam, the Netherlands
| | - Philip J. Kilner
- Cardiovascular Magnetic Resonance Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP UK
| | - Albert C. van Rossum
- Cardiology, ICaR-VU, VU University Medical Center, PO Box 7057, 1007 MB Amsterdam, the Netherlands
| | - Peter D. Gatehouse
- Cardiovascular Magnetic Resonance Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP UK
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9
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Balédent O, Czosnyka Z, Czosnyka M. "Bucket" cerebrospinal fluid bulk flow-is it a fact or a fiction? Acta Neurochir (Wien) 2019; 161:257-258. [PMID: 30421028 DOI: 10.1007/s00701-018-3731-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 11/06/2018] [Indexed: 11/27/2022]
Affiliation(s)
- Olivier Balédent
- University of Picardie Jules Verne, Chimère EA 7516, CHU, 80054, Amiens, France
| | - Zofia Czosnyka
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Cambridge University, Box 167, Addenbrookes Hospital, Cambridge, CB20QQ, UK
| | - Marek Czosnyka
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Cambridge University, Box 167, Addenbrookes Hospital, Cambridge, CB20QQ, UK.
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Bidhult S, Töger J, Heiberg E, Carlsson M, Arheden H, Aletras AH, Hedström E. Independent validation of metric optimized gating for fetal cardiovascular phase-contrast flow imaging. Magn Reson Med 2019; 81:495-503. [PMID: 30159933 PMCID: PMC6282515 DOI: 10.1002/mrm.27392] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 05/11/2018] [Accepted: 05/14/2018] [Indexed: 11/24/2022]
Abstract
PURPOSE To validate metric optimized gating phase-contrast MR (MOG PC-MR) flow measurements for a range of fetal flow velocities in phantom experiments. 2) To investigate intra- and interobserver variability for fetal flow measurements at an imaging center other than the original site. METHODS MOG PC-MR was compared to timer/beaker measurements in a pulsatile flow phantom using a heart rate (∼145 bpm), nozzle diameter (∼6 mm), and flow range (∼130-700 mL/min) similar to fetal imaging. Fifteen healthy fetuses were included for intra- and interobserver variability in the fetal descending aorta and umbilical vein. RESULTS Phantom MOG PC-MR flow bias and variability was 2% ± 23%. Accuracy of MOG PC-MR was degraded for flow profiles with low velocity-to-noise ratio. Intra- and interobserver coefficients of variation were 6% and 19%, respectively, for fetal descending aorta; and 10% and 17%, respectively, for the umbilical vein. CONCLUSION Phantom validation showed good agreement between MOG and conventionally gated PC-MR, except for cases with low velocity-to-noise ratio, which resulted in MOG misgating and underestimated peak velocities and warranted optimization of sequence parameters to individual fetal vessels. Inter- and intraobserver variability for fetal MOG PC-MR imaging were comparable to previously reported values.
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Affiliation(s)
- Sebastian Bidhult
- Lund University, Skane University HospitalDepartment of Clinical Sciences Lund, Clinical PhysiologyLundSweden
- Lund UniversityDepartment of Biomedical Engineering, Faculty of EngineeringLundSweden
| | - Johannes Töger
- Lund University, Skane University HospitalDepartment of Clinical Sciences Lund, Clinical PhysiologyLundSweden
| | - Einar Heiberg
- Lund University, Skane University HospitalDepartment of Clinical Sciences Lund, Clinical PhysiologyLundSweden
- Lund UniversityDepartment of Biomedical Engineering, Faculty of EngineeringLundSweden
| | - Marcus Carlsson
- Lund University, Skane University HospitalDepartment of Clinical Sciences Lund, Clinical PhysiologyLundSweden
| | - Håkan Arheden
- Lund University, Skane University HospitalDepartment of Clinical Sciences Lund, Clinical PhysiologyLundSweden
| | - Anthony H. Aletras
- Lund University, Skane University HospitalDepartment of Clinical Sciences Lund, Clinical PhysiologyLundSweden
- Laboratory of Computing, Medical Informatics and Biomedical–Imaging Technologies, School of MedicineAristotle University of ThessalonikiGreece
| | - Erik Hedström
- Lund University, Skane University HospitalDepartment of Clinical Sciences Lund, Clinical PhysiologyLundSweden
- Lund University, Skane University HospitalDepartment of Clinical Sciences Lund, Diagnostic RadiologyLundSweden
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11
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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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12
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Biesbroek PS, Heslinga SC, van de Ven PM, Peters MJL, Amier RP, Konings TC, Maroules CD, Ayers C, Joshi PH, van der Horst-Bruinsma IE, van Halm VP, van Rossum AC, Nurmohamed MT, Nijveldt R. Assessment of aortic stiffness in patients with ankylosing spondylitis using cardiovascular magnetic resonance. Clin Rheumatol 2018; 37:2151-2159. [DOI: 10.1007/s10067-018-4135-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 04/24/2018] [Accepted: 05/01/2018] [Indexed: 12/23/2022]
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13
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Quantitative magnetic resonance imaging phantoms: A review and the need for a system phantom. Magn Reson Med 2017; 79:48-61. [DOI: 10.1002/mrm.26982] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 09/01/2017] [Accepted: 10/04/2017] [Indexed: 01/16/2023]
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14
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Hassan M, Wagdy K, Kharabish A, Selwanos PP, Nabil A, Elguindy A, ElFaramawy A, Elmahdy MF, Mahmoud H, Yacoub MH. Validation of Noninvasive Measurement of Cardiac Output Using Inert Gas Rebreathing in a Cohort of Patients With Heart Failure and Reduced Ejection Fraction. Circ Heart Fail 2017; 10:CIRCHEARTFAILURE.116.003592. [PMID: 28283502 DOI: 10.1161/circheartfailure.116.003592] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 02/03/2017] [Indexed: 01/25/2023]
Abstract
BACKGROUND Cardiac output (CO) is a key indicator of cardiac function in patients with heart failure. No completely accurate method is available for measuring CO in all patients. The objective of this study was to validate CO measurement using the inert gas rebreathing (IGR) method against other noninvasive and invasive methods of CO quantification in a cohort of patients with heart failure and reduced ejection fraction. METHODS AND RESULTS The study included 97 patients with heart failure and reduced ejection fraction (age 42±15.5 years; 64 patients (65.9%) had idiopathic dilated cardiomyopathy and 21 patients (21.6%) had ischemic heart disease). Median left ventricle ejection fraction was 24% (10%-36%). Patients with atrial fibrillation were excluded. CO was measured using 4 methods (IGR, cardiac magnetic resonance imaging, cardiac catheterization, and echocardiography) and indexed to body surface area (cardiac index [CI]). All studies were performed within 48 hours. Median CI measured by IGR was 1.75, by cardiac magnetic resonance imaging was 1.82, by cardiac catheterization was 1.65, and by echo was 1.7 L·min-1·m-2. There were significant modest linear correlations between IGR-derived CI and cardiac magnetic resonance imaging-derived CI (r=0.7; P<0.001), as well as cardiac catheterization-derived CI (r=0.6; P<0.001). Using Bland-Altman analysis, the agreement between the IGR method and the other methods was as good as the agreement between any 2 other methods with each other. CONCLUSIONS The IGR method is a simple, accurate, and reproducible noninvasive method for quantification of CO in patients with advanced heart failure. The prognostic value of this simple measurement needs to be studied prospectively.
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Affiliation(s)
- Mohamed Hassan
- From the Cardiology Department (M.H., A.E., M.F.E.) and Radiology Department (A.K.), Cairo University, Egypt; Cardiology Department (M.H., K.W., P.P.S., A.E., H.M.), Radiology Department (A.K.), Biomedical Engineering Department (A.N.), and Cardiothoracic Department (M.H.Y.), Aswan Heart Centre, Egypt; and Imperial College, London, United Kingdom (M.H.Y.)
| | - Kerolos Wagdy
- From the Cardiology Department (M.H., A.E., M.F.E.) and Radiology Department (A.K.), Cairo University, Egypt; Cardiology Department (M.H., K.W., P.P.S., A.E., H.M.), Radiology Department (A.K.), Biomedical Engineering Department (A.N.), and Cardiothoracic Department (M.H.Y.), Aswan Heart Centre, Egypt; and Imperial College, London, United Kingdom (M.H.Y.)
| | - Ahmed Kharabish
- From the Cardiology Department (M.H., A.E., M.F.E.) and Radiology Department (A.K.), Cairo University, Egypt; Cardiology Department (M.H., K.W., P.P.S., A.E., H.M.), Radiology Department (A.K.), Biomedical Engineering Department (A.N.), and Cardiothoracic Department (M.H.Y.), Aswan Heart Centre, Egypt; and Imperial College, London, United Kingdom (M.H.Y.)
| | - Peter Philip Selwanos
- From the Cardiology Department (M.H., A.E., M.F.E.) and Radiology Department (A.K.), Cairo University, Egypt; Cardiology Department (M.H., K.W., P.P.S., A.E., H.M.), Radiology Department (A.K.), Biomedical Engineering Department (A.N.), and Cardiothoracic Department (M.H.Y.), Aswan Heart Centre, Egypt; and Imperial College, London, United Kingdom (M.H.Y.)
| | - Ahmed Nabil
- From the Cardiology Department (M.H., A.E., M.F.E.) and Radiology Department (A.K.), Cairo University, Egypt; Cardiology Department (M.H., K.W., P.P.S., A.E., H.M.), Radiology Department (A.K.), Biomedical Engineering Department (A.N.), and Cardiothoracic Department (M.H.Y.), Aswan Heart Centre, Egypt; and Imperial College, London, United Kingdom (M.H.Y.)
| | - Ahmed Elguindy
- From the Cardiology Department (M.H., A.E., M.F.E.) and Radiology Department (A.K.), Cairo University, Egypt; Cardiology Department (M.H., K.W., P.P.S., A.E., H.M.), Radiology Department (A.K.), Biomedical Engineering Department (A.N.), and Cardiothoracic Department (M.H.Y.), Aswan Heart Centre, Egypt; and Imperial College, London, United Kingdom (M.H.Y.)
| | - Amr ElFaramawy
- From the Cardiology Department (M.H., A.E., M.F.E.) and Radiology Department (A.K.), Cairo University, Egypt; Cardiology Department (M.H., K.W., P.P.S., A.E., H.M.), Radiology Department (A.K.), Biomedical Engineering Department (A.N.), and Cardiothoracic Department (M.H.Y.), Aswan Heart Centre, Egypt; and Imperial College, London, United Kingdom (M.H.Y.)
| | - Mahmoud F Elmahdy
- From the Cardiology Department (M.H., A.E., M.F.E.) and Radiology Department (A.K.), Cairo University, Egypt; Cardiology Department (M.H., K.W., P.P.S., A.E., H.M.), Radiology Department (A.K.), Biomedical Engineering Department (A.N.), and Cardiothoracic Department (M.H.Y.), Aswan Heart Centre, Egypt; and Imperial College, London, United Kingdom (M.H.Y.)
| | - Hani Mahmoud
- From the Cardiology Department (M.H., A.E., M.F.E.) and Radiology Department (A.K.), Cairo University, Egypt; Cardiology Department (M.H., K.W., P.P.S., A.E., H.M.), Radiology Department (A.K.), Biomedical Engineering Department (A.N.), and Cardiothoracic Department (M.H.Y.), Aswan Heart Centre, Egypt; and Imperial College, London, United Kingdom (M.H.Y.)
| | - Magdi H Yacoub
- From the Cardiology Department (M.H., A.E., M.F.E.) and Radiology Department (A.K.), Cairo University, Egypt; Cardiology Department (M.H., K.W., P.P.S., A.E., H.M.), Radiology Department (A.K.), Biomedical Engineering Department (A.N.), and Cardiothoracic Department (M.H.Y.), Aswan Heart Centre, Egypt; and Imperial College, London, United Kingdom (M.H.Y.).
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15
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Phase Error Correction in Time-Averaged 3D Phase Contrast Magnetic Resonance Imaging of the Cerebral Vasculature. PLoS One 2016; 11:e0149930. [PMID: 26910600 PMCID: PMC4765993 DOI: 10.1371/journal.pone.0149930] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 02/05/2016] [Indexed: 11/19/2022] Open
Abstract
Purpose Volume flow rate (VFR) measurements based on phase contrast (PC)-magnetic resonance (MR) imaging datasets have spatially varying bias due to eddy current induced phase errors. The purpose of this study was to assess the impact of phase errors in time averaged PC-MR imaging of the cerebral vasculature and explore the effects of three common correction schemes (local bias correction (LBC), local polynomial correction (LPC), and whole brain polynomial correction (WBPC)). Methods Measurements of the eddy current induced phase error from a static phantom were first obtained. In thirty healthy human subjects, the methods were then assessed in background tissue to determine if local phase offsets could be removed. Finally, the techniques were used to correct VFR measurements in cerebral vessels and compared statistically. Results In the phantom, phase error was measured to be <2.1 ml/s per pixel and the bias was reduced with the correction schemes. In background tissue, the bias was significantly reduced, by 65.6% (LBC), 58.4% (LPC) and 47.7% (WBPC) (p < 0.001 across all schemes). Correction did not lead to significantly different VFR measurements in the vessels (p = 0.997). In the vessel measurements, the three correction schemes led to flow measurement differences of -0.04 ± 0.05 ml/s, 0.09 ± 0.16 ml/s, and -0.02 ± 0.06 ml/s. Although there was an improvement in background measurements with correction, there was no statistical difference between the three correction schemes (p = 0.242 in background and p = 0.738 in vessels). Conclusions While eddy current induced phase errors can vary between hardware and sequence configurations, our results showed that the impact is small in a typical brain PC-MR protocol and does not have a significant effect on VFR measurements in cerebral vessels.
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16
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Jorstig S, Waldenborg M, Lidén M, Wodecki M, Thunberg P. Determination of Right Ventricular Volume by Combining Echocardiographic Distance Measurements. Echocardiography 2016; 33:844-53. [PMID: 26841195 DOI: 10.1111/echo.13173] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND The position of the right ventricle (RV), often partly behind the sternum, implies difficulties to image the RV free wall using transthoracic echocardiography (TTE) and consequently limits the possibilities of stroke volume calculations. The aim of this study was to evaluate whether the volume of the right ventricle (RV) can be determined by combining TTE distance measurements that do not need the RV free wall to be fully visualized. METHODS The RV volume was approximated by an ellipsoid composed of three distances. Distance measurements, modeled RV stroke volumes (RVSV), and RV ejection fraction (RVEF) were compared to reference values obtained from cardiac magnetic resonance (CMR) imaging for 12 healthy volunteers. RESULTS Inter-modality comparisons showed that distance measurements were significantly underestimated in TTE compared to CMR. The modeled RV volumes using TTE distance measurements were underestimated compared to reference CMR volumes. There was, however, for TTE an agreement between modeled RVSV and left ventricular stroke volumes determined by biplane Simpson's rule. Similar agreement was shown between modeled RVSV based on CMR distance measurements and the CMR reference. Regarding RVEF, further studies including patients with a wider range of RVEF are needed to evaluate the method. CONCLUSION In conclusion, the ellipsoid model of the RV provides good estimates of RVSVs, but volumes based on distance measurements from different modalities cannot be used interchangeably.
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Affiliation(s)
- Stina Jorstig
- School of Health and Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Micael Waldenborg
- School of Health and Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.,Department of Clinical Physiology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Mats Lidén
- School of Health and Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.,Department of Radiology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Maciej Wodecki
- Department of Clinical Physiology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
| | - Per Thunberg
- School of Health and Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.,Department of Medical Physics, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
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17
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Polte CL, Bech-Hanssen O, Johnsson ÅA, Gao SA, Lagerstrand KM. Mitral regurgitation quantification by cardiovascular magnetic resonance: a comparison of indirect quantification methods. Int J Cardiovasc Imaging 2015; 31:1223-31. [DOI: 10.1007/s10554-015-0681-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 05/13/2015] [Indexed: 11/30/2022]
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18
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Töger J, Bidhult S, Revstedt J, Carlsson M, Arheden H, Heiberg E. Independent validation of four-dimensional flow MR velocities and vortex ring volume using particle imaging velocimetry and planar laser-Induced fluorescence. Magn Reson Med 2015; 75:1064-75. [PMID: 25940239 DOI: 10.1002/mrm.25683] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 02/10/2015] [Accepted: 02/10/2015] [Indexed: 11/11/2022]
Abstract
PURPOSE This study aimed to: (i) present and characterize a phantom setup for validation of four-dimensional (4D) flow using particle imaging velocimetry (PIV) and planar laser-induced fluorescence (PLIF); (ii) validate 4D flow velocity measurements using PIV; and (iii) validate 4D flow vortex ring volume (VV) using PLIF. METHODS A pulsatile pump and a tank with a 25-mm nozzle were constructed. PIV measurements (1.5 × 1.5 mm pixels, temporal resolution 10 ms) were obtained on two occasions. The 4D flow (3 × 3 × 3 mm voxels, temporal resolution 50 ms) was acquired using SENSE = 2. VV was quantified using PLIF and 4D flow. RESULTS PIV showed excellent day-to-day stability (R(2) = 0.99, bias -0.04 ± 0.72 cm/s). The 4D flow mean velocities agreed well with PIV (R(2) = 0.95, bias 0.16 ± 2.65 cm/s). Peak velocities in 4D flow were underestimated by 7-18% compared with PIV (y = 0.79x + 2.7, R(2) = 0.96, -12 ± 5%). VV showed excellent agreement between PLIF and 4D flow (R(2) = 0.99, 2.4 ± 1.5 mL). CONCLUSION This study shows: (i) The proposed phantom enables reliable validation of 4D flow. (ii) 4D flow velocities show good agreement with PIV, but peak velocities were underestimated due to low spatial and temporal resolution. (iii) Vortex ring volume (VV) can be quantified using 4D flow.
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Affiliation(s)
- Johannes Töger
- Department of Clinical Physiology, Lund University Hospital, Lund, Lund University, Lund, Sweden.,Department of Numerical Analysis, Centre for Mathematical Sciences, Lund University, Lund, Sweden
| | - Sebastian Bidhult
- Department of Clinical Physiology, Lund University Hospital, Lund, Lund University, Lund, Sweden.,Department of Biomedical Engineering, Faculty of Engineering, Lund University, Lund, Sweden
| | - Johan Revstedt
- Department of Energy Sciences, Faculty of Engineering, Lund University, Lund, Sweden
| | - Marcus Carlsson
- Department of Clinical Physiology, Lund University Hospital, Lund, Lund University, Lund, Sweden
| | - Håkan Arheden
- Department of Clinical Physiology, Lund University Hospital, Lund, Lund University, Lund, Sweden
| | - Einar Heiberg
- Department of Clinical Physiology, Lund University Hospital, Lund, Lund University, Lund, Sweden.,Department of Numerical Analysis, Centre for Mathematical Sciences, Lund University, Lund, Sweden.,Department of Biomedical Engineering, Faculty of Engineering, Lund University, Lund, Sweden
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Busch J, Vannesjo SJ, Barmet C, Pruessmann KP, Kozerke S. Analysis of temperature dependence of background phase errors in phase-contrast cardiovascular magnetic resonance. J Cardiovasc Magn Reson 2014; 16:97. [PMID: 25497004 PMCID: PMC4263200 DOI: 10.1186/s12968-014-0097-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 11/14/2014] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND The accuracy of phase-contrast cardiovascular magnetic resonance (PC-CMR) can be compromised by background phase errors. It is the objective of the present work to provide an analysis of the temperature dependence of background phase errors in PC-CMR by means of gradient mount temperature sensing and magnetic field monitoring. METHODS Background phase errors were measured for various temperatures of the gradient mount using magnetic field monitoring and validated in a static phantom. The effect of thermal changes during k-space acquisition was simulated and confirmed with measurements in a stationary phantom. RESULTS The temperature of the gradient mount was found to increase by 20-30 K during PC-CMR measurements of 6-12 min duration. Associated changes in background phase errors of up to 11% or 0.35 radian were measured at 10 cm from the magnet's iso-center as a result of first order offsets. Zeroth order phase errors exhibited little thermal dependence. CONCLUSIONS It is concluded that changes in gradient mount temperature significantly modify background phase errors during PC-CMR with high gradient duty cycle. Since temperature increases significantly during the first minutes of scanning the results presented are also of relevance for single-slice or multi-slice PC-CMR scans. The findings prompt for further studies to investigate advanced correction methods taking into account gradient temperature and/or the use of concurrent field-monitoring to map gradient-induced fields throughout the scan.
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Affiliation(s)
- Julia Busch
- />Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - S Johanna Vannesjo
- />Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Christoph Barmet
- />Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland
- />Skope Magnetic Resonance Technologies, Zurich, Switzerland
| | - Klaas P Pruessmann
- />Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Sebastian Kozerke
- />Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland
- />Division of Imaging Science and Biomedical Engineering, King’s College London, London, UK
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20
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Jorstig S, Emilsson K, Lidén M, Thunberg P. A study to determine the contribution to right ventricle stroke volume from pulmonary and tricuspid valve displacement volumes. Clin Physiol Funct Imaging 2014; 35:283-90. [PMID: 24810859 DOI: 10.1111/cpf.12162] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 04/14/2014] [Indexed: 11/28/2022]
Abstract
BACKGROUND Describing the systolic function of the right ventricle (RV) is a difficult task due to the complex shape and orientation of the RV. The purpose of this study was to investigate the extent to which the volumes encompassed by the pulmonary and tricuspid valve displacements contribute to the total right ventricle stroke volume (RVSV). METHODS Twelve healthy volunteers were examined using cardiac magnetic resonance (CMR). Two series of time-resolved axially rotated MR images were acquired that encompassed the tricuspid valve and the pulmonary valve, respectively. The volume related to each valve movement, the tricuspid plane displacement (TPD) and the pulmonary plane displacement (PPD), was determined by delineation in diastole and systole. These volumes, RVSV(TPD) and RVSV(PPD) , were compared to the stroke volume to determine the contributions to the total stroke volume from the TPD and the PPD. The remaining volume of the total RVSV was referred to as RVSV(Other) . An initial in vitro study was carried out to validate the accuracy of volume measurements using axially rotated images. RESULTS In vitro measurements indicated that the method for volumetric measurements using axially rotated images was a very accurate one, with a mean difference of 0·04 ± 0·10 ml. The in vivo measurements of RVSV(TPD) , RVSV(PPD) and RVSVOther were 45 ± 10%, 13 ± 2% and 42 ± 11%, respectively. CONCLUSIONS Right ventricle stroke volume is determined by different individual volume changes as follows: RVSV(TPD) together with RVSVOther contributes to almost the entire RVSV in nearly equal proportions, while RVSV(PPD) contributes only a small amount and is approximately 30% of either RVSV(TPD) or RVSV(Other) .
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Affiliation(s)
- Stina Jorstig
- School of Health and Medical Sciences, Örebro University, Örebro, Sweden
| | - Kent Emilsson
- School of Health and Medical Sciences, Örebro University, Örebro, Sweden.,Department of Clinical Physiology, Örebro University Hospital, Örebro, Sweden
| | - Mats Lidén
- School of Health and Medical Sciences, Örebro University, Örebro, Sweden.,Department of Radiology, Örebro University Hospital, Örebro, Sweden
| | - Per Thunberg
- School of Health and Medical Sciences, Örebro University, Örebro, Sweden.,Department of Medical Physics, Örebro University Hospital, Örebro, Sweden
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21
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Espe EK, Zhang L, Sjaastad I. Unwrapping eddy current compensation: Improved compensation of eddy current induced baseline shifts in high-resolution phase-contrast MRI at 9.4 tesla. Magn Reson Med 2013; 72:1096-102. [DOI: 10.1002/mrm.25023] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 09/24/2013] [Accepted: 10/09/2013] [Indexed: 11/06/2022]
Affiliation(s)
- Emil K.S. Espe
- Institute for Experimental Medical Research; Oslo University Hospital and University of Oslo; Oslo Norway
- KG Jebsen Cardiac Research Center and Center for Heart Failure Research; University of Oslo; Oslo Norway
| | - Lili Zhang
- Institute for Experimental Medical Research; Oslo University Hospital and University of Oslo; Oslo Norway
- KG Jebsen Cardiac Research Center and Center for Heart Failure Research; University of Oslo; Oslo Norway
| | - Ivar Sjaastad
- Institute for Experimental Medical Research; Oslo University Hospital and University of Oslo; Oslo Norway
- KG Jebsen Cardiac Research Center and Center for Heart Failure Research; University of Oslo; Oslo Norway
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22
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Espe EKS, Aronsen JM, Skårdal K, Schneider JE, Zhang L, Sjaastad I. Novel insight into the detailed myocardial motion and deformation of the rodent heart using high-resolution phase contrast cardiovascular magnetic resonance. J Cardiovasc Magn Reson 2013; 15:82. [PMID: 24034168 PMCID: PMC3848852 DOI: 10.1186/1532-429x-15-82] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 09/03/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Phase contrast velocimetry cardiovascular magnetic resonance (PC-CMR) is a powerful and versatile tool allowing assessment of in vivo motion of the myocardium. However, PC-CMR is sensitive to motion related artifacts causing errors that are geometrically systematic, rendering regional analysis of myocardial function challenging. The objective of this study was to establish an optimized PC-CMR method able to provide novel insight in the complex regional motion and strain of the rodent myocardium, and provide a proof-of-concept in normal and diseased rat hearts with higher temporal and spatial resolution than previously reported. METHODS A PC-CMR protocol optimized for assessing the motion and deformation of the myocardium in rats with high spatiotemporal resolution was established, and ten animals with different degree of cardiac dysfunction underwent examination and served as proof-of-concept. Global and regional myocardial velocities and circumferential strain were calculated, and the results were compared to five control animals. Furthermore, the global strain measurements were validated against speckle-tracking echocardiography, and inter- and intrastudy variability of the protocol were evaluated. RESULTS The presented method allows assessment of regional myocardial function in rats with high level of detail; temporal resolution was 3.2 ms, and analysis was done using 32 circumferential segments. In the dysfunctional hearts, global and regional function were distinctly altered, including reduced global peak values, increased regional heterogeneity and increased index of dyssynchrony. Strain derived from the PC-CMR data was in excellent agreement with echocardiography (r = 0.95, p < 0.001; limits-of-agreement -0.02 ± 3.92%strain), and intra- and interstudy variability were low for both velocity and strain (limits-of-agreement, radial motion: 0.01 ± 0.32 cm/s and -0.06 ± 0.75 cm/s; circumferential strain: -0.16 ± 0.89%strain and -0.71 ± 1.67%strain, for intra- and interstudy, respectively). CONCLUSION We demonstrate, for the first time, that PC-CMR enables high-resolution evaluation of in vivo circumferential strain in addition to myocardial motion of the rat heart. In combination with the superior geometric robustness of CMR, this ultimately provides a tool for longitudinal studies of regional function in rodents with high level of detail.
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Affiliation(s)
- Emil KS Espe
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Kirkeveien 166, N-0407, Oslo, Norway
- KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Jan Magnus Aronsen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Kirkeveien 166, N-0407, Oslo, Norway
- KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway
- Bjørknes College, Oslo, Norway
| | - Kristine Skårdal
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Kirkeveien 166, N-0407, Oslo, Norway
- KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | | | - Lili Zhang
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Kirkeveien 166, N-0407, Oslo, Norway
- KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Kirkeveien 166, N-0407, Oslo, Norway
- KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway
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Pennell DJ, Baksi AJ, Carpenter JP, Firmin DN, Kilner PJ, Mohiaddin RH, Prasad SK. Review of Journal of Cardiovascular Magnetic Resonance 2012. J Cardiovasc Magn Reson 2013; 15:76. [PMID: 24006874 PMCID: PMC3847143 DOI: 10.1186/1532-429x-15-76] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 08/22/2013] [Indexed: 02/07/2023] Open
Abstract
There were 90 articles published in the Journal of Cardiovascular Magnetic Resonance (JCMR) in 2012, which is an 8% increase in the number of articles since 2011. The quality of the submissions continues to increase. The editors are delighted to report that the 2011 JCMR Impact Factor (which is published in June 2012) has risen to 4.44, up from 3.72 for 2010 (as published in June 2011), a 20% increase. The 2011 impact factor means that the JCMR papers that were published in 2009 and 2010 were cited on average 4.44 times in 2011. The impact factor undergoes natural variation according to citation rates of papers in the 2 years following publication, and is significantly influenced by highly cited papers such as official reports. However, the progress of the journal's impact over the last 5 years has been impressive. Our acceptance rate is approximately 25%, and has been falling as the number of articles being submitted has been increasing. In accordance with Open-Access publishing, the JCMR articles go on-line as they are accepted with no collating of the articles into sections or special thematic issues. For this reason, the Editors have felt that it is useful once per calendar year to summarize the papers for the readership into broad areas of interest or theme, so that areas of interest can be reviewed in a single article in relation to each other and other recent JCMR articles. The papers are presented in broad themes and set in context with related literature and previously published JCMR papers to guide continuity of thought in the journal. We hope that you find the open-access system increases wider reading and citation of your papers, and that you will continue to send your quality manuscripts to JCMR for publication.
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Affiliation(s)
- Dudley J Pennell
- Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP, UK
- Imperial College, London, UK
| | - A John Baksi
- Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP, UK
- Imperial College, London, UK
| | - John Paul Carpenter
- Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP, UK
- Imperial College, London, UK
| | - David N Firmin
- Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP, UK
- Imperial College, London, UK
| | - Philip J Kilner
- Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP, UK
- Imperial College, London, UK
| | - Raad H Mohiaddin
- Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP, UK
- Imperial College, London, UK
| | - Sanjay K Prasad
- Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, Sydney Street, London, SW3 6NP, UK
- Imperial College, London, UK
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24
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Middione MJ, Thompson RB, Ennis DB. Velocity encoding with the slice select refocusing gradient for faster imaging and reduced chemical shift-induced phase errors. Magn Reson Med 2013; 71:2014-23. [DOI: 10.1002/mrm.24861] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 05/31/2013] [Accepted: 06/07/2013] [Indexed: 11/08/2022]
Affiliation(s)
- Matthew J. Middione
- Department of Radiological Sciences; University of California; Los Angeles California USA
- Biomedical Physics Interdepartmental Program; University of California; Los Angeles California USA
| | - Richard B. Thompson
- Department of Biomedical Engineering; University of Alberta; Edmonton Alberta Canada
| | - Daniel B. Ennis
- Department of Radiological Sciences; University of California; Los Angeles California USA
- Biomedical Physics Interdepartmental Program; University of California; Los Angeles California USA
- Department of Bioengineering; University of California; Los Angeles California USA
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25
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Bennett CJ, Maleszewski JJ, Araoz PA. CT and MR imaging of the aortic valve: radiologic-pathologic correlation. Radiographics 2013; 32:1399-420. [PMID: 22977027 DOI: 10.1148/rg.325115727] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Valvular disease is estimated to account for as many as 20% of cardiac surgical procedures performed in the United States. It may be congenital in origin or secondary to another disease process. One congenital anomaly, bicuspid aortic valve, is associated with increased incidence of stenosis, regurgitation, endocarditis, and aneurysmal dilatation of the aorta. A bicuspid valve has two cusps instead of the normal three; resultant fusion or poor excursion of the valve leaflets may lead to aortic stenosis, the presence of which is signaled by dephasing jets on magnetic resonance (MR) images. Surgery is generally recommended for patients with severe stenosis who are symptomatic or who have significant ventricular dysfunction; transcatheter aortic valve implantation (TAVI) is an emerging therapeutic option for patients who are not eligible for surgical treatment. Computed tomography (CT) is an essential component of preoperative planning for TAVI; it is used to determine the aortic root dimensions, severity of peripheral vascular disease, and status of the coronary arteries. Aortic regurgitation, which is caused by incompetent closure of the aortic valve, likewise leads to the appearance of jets on MR images. The severity of regurgitation is graded on the basis of valvular morphologic parameters; qualitative assessment of dephasing jets at Doppler ultrasonography; or measurements of the regurgitant fraction, volume, and orifice area. Mild regurgitation is managed conservatively, whereas severe or symptomatic regurgitation usually leads to valve replacement surgery, especially in the presence of substantial left ventricular enlargement or dysfunction. Bacterial endocarditis, although less common than aortic stenosis and regurgitation, is associated with substantial morbidity and mortality. Electrocardiographically gated CT reliably demonstrates infectious vegetations and benign excrescences of 1 cm or more on the valve surface, allowing the assessment of any embolic complications.
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27
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Pennell DJ, Carpenter JP, Firmin DN, Kilner PJ, Mohiaddin RH, Prasad SK. Review of Journal of Cardiovascular Magnetic Resonance 2011. J Cardiovasc Magn Reson 2012; 14:78. [PMID: 23158097 PMCID: PMC3519784 DOI: 10.1186/1532-429x-14-78] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 11/08/2012] [Indexed: 12/15/2022] Open
Abstract
There were 83 articles published in the Journal of Cardiovascular Magnetic Resonance (JCMR) in 2011, which is an 11% increase in the number of articles since 2010. The quality of the submissions continues to increase. The editors had been delighted with the 2010 JCMR Impact Factor of 4.33, although this fell modestly to 3.72 for 2011. The impact factor undergoes natural variation according to citation rates of papers in the 2 years following publication, and is significantly influenced by highly cited papers such as official reports. However, we remain very pleased with the progress of the journal's impact over the last 5 years. Our acceptance rate is approximately 25%, and has been falling as the number of articles being submitted has been increasing. In accordance with Open-Access publishing, the JCMR articles go on-line as they are accepted with no collating of the articles into sections or special thematic issues. For this reason, the Editors feel it is useful to summarize the papers for the readership into broad areas of interest or theme, which we feel would be useful, so that areas of interest from the previous year can be reviewed in a single article in relation to each other and other recent JCMR articles. The papers are presented in broad themes and set in context with related literature and previously published JCMR papers to guide continuity of thought in the journal. We hope that you find the open-access system increases wider reading and citation of your papers, and that you will continue to send your quality manuscripts to JCMR for publication.
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Affiliation(s)
- Dudley J Pennell
- CMR Unit Royal Brompton Hospital, Sydney Street, London, SW3 6NP, UK
- National Heart and Lung Institute, Imperial College, Exhibition Road, London, SW7 2AZ, UK
| | - John Paul Carpenter
- CMR Unit Royal Brompton Hospital, Sydney Street, London, SW3 6NP, UK
- National Heart and Lung Institute, Imperial College, Exhibition Road, London, SW7 2AZ, UK
| | - David N Firmin
- CMR Unit Royal Brompton Hospital, Sydney Street, London, SW3 6NP, UK
- National Heart and Lung Institute, Imperial College, Exhibition Road, London, SW7 2AZ, UK
| | - Philip J Kilner
- CMR Unit Royal Brompton Hospital, Sydney Street, London, SW3 6NP, UK
- National Heart and Lung Institute, Imperial College, Exhibition Road, London, SW7 2AZ, UK
| | - Raad H Mohiaddin
- CMR Unit Royal Brompton Hospital, Sydney Street, London, SW3 6NP, UK
- National Heart and Lung Institute, Imperial College, Exhibition Road, London, SW7 2AZ, UK
| | - Sanjay K Prasad
- CMR Unit Royal Brompton Hospital, Sydney Street, London, SW3 6NP, UK
- National Heart and Lung Institute, Imperial College, Exhibition Road, London, SW7 2AZ, UK
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28
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Gatehouse PD, Rolf MP, Bloch KM, Graves MJ, Kilner PJ, Firmin DN, Hofman MBM. A multi-center inter-manufacturer study of the temporal stability of phase-contrast velocity mapping background offset errors. J Cardiovasc Magn Reson 2012; 14:72. [PMID: 23083397 PMCID: PMC3514147 DOI: 10.1186/1532-429x-14-72] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Accepted: 10/01/2012] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Phase-contrast velocity images often contain a background or baseline offset error, which adds an unknown offset to the measured velocities. For accurate flow measurements, this offset must be shown negligible or corrected. Some correction techniques depend on replicating the clinical flow acquisition using a uniform stationary phantom, in order to measure the baseline offset at the region of interest and subtract it from the clinical study. Such techniques assume that the background offset is stable over the time of a patient scan, or even longer if the phantom scans are acquired later, or derived from pre-stored background correction images. There is no published evidence regarding temporal stability of the background offset. METHODS This study assessed the temporal stability of the background offset on 3 different manufacturers' scanners over 8 weeks, using a retrospectively-gated phase-contrast cine acquisition with fixed parameters and at a fixed location, repeated 5 times in rapid succession each week. A significant offset was defined as 0.6 cm/s within 50 mm of isocenter, based upon an accuracy of 10% in a typical cardiac shunt measurement. RESULTS Over the 5 repeated cine acquisitions, temporal drift in the baseline offset was insignificant on two machines (0.3 cm/s, 0.2 cm/s), and marginally insignificant on the third machine (0.5 cm/s) due to an apparent heating effect. Over a longer timescale of 8 weeks, insignificant drift (0.4 cm/s) occurred on one, with larger drifts (0.9 cm/s, 0.6 cm/s) on the other machines. CONCLUSIONS During a typical patient study, background drift was insignificant. Extended high gradient power scanning with work requires care to avoid drift on some machines. Over the longer term of 8 weeks, significant drift is likely, preventing accurate correction by delayed phantom corrections or derivation from pre-stored background offset data.
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Affiliation(s)
| | - Marijn P Rolf
- VU University Medical Center, ICaR-VU, Amsterdam, Netherlands
| | | | | | | | | | - Mark BM Hofman
- VU University Medical Center, ICaR-VU, Amsterdam, Netherlands
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29
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Nilsson A, Markenroth Bloch K, Carlsson M, Heiberg E, Ståhlberg F. Variable velocity encoding in a three-dimensional, three-directional phase contrast sequence: Evaluation in phantom and volunteers. J Magn Reson Imaging 2012; 36:1450-9. [PMID: 23065951 DOI: 10.1002/jmri.23778] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 07/20/2012] [Indexed: 01/04/2023] Open
Abstract
PURPOSE To evaluate accuracy and noise properties of a novel time-resolved, three-dimensional, three-directional phase contrast sequence with variable velocity encoding (denoted 4D-vPC) on a 3 Tesla MR system, and to investigate potential benefits and limitations of variable velocity encoding with respect to depicting blood flow patterns. MATERIALS AND METHODS A 4D PC-MRI sequence was modified to allow variable velocity encoding (VENC) over the cardiac cycle in all three velocity directions independently. 4D-PC sequences with constant and variable VENC were compared in a rotating phantom with respect to measured velocities and noise levels. Additionally, comparison of flow patterns in the ascending aorta was performed in six healthy volunteers. RESULTS Phantom measurements showed a linear relationship between velocity noise and velocity encoding. 4D-vPC MRI presented lower noise levels than 4D-PC both in phantom and in volunteer measurements, in agreement with theory. Volunteer comparisons revealed more consistent and detailed flow patterns in early diastole for the variable VENC sequences. CONCLUSION Variable velocity encoding offers reduced noise levels compared with sequences with constant velocity encoding by optimizing the velocity-to-noise ratio (VNR) to the hemodynamic properties of the imaged area. Increased VNR ratios could be beneficial for blood flow visualizations of pathology in the cardiac cycle.
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Affiliation(s)
- Anders Nilsson
- Department of Medical Radiation Physics, Lund University, Lund, Sweden.
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30
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Dieringer MA, Hentschel J, de Quadros T, von Knobelsdorff-Brenkenhoff F, Hoffmann W, Niendorf T, Schulz-Menger J. Design, construction, and evaluation of a dynamic MR compatible cardiac left ventricle model. Med Phys 2012; 39:4800-6. [PMID: 22894405 DOI: 10.1118/1.4736954] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
PURPOSE Development of magnetic resonance (MR) sequences is important to answer clinical questions and to overcome current limitations. To meet the challenges of cardiac MR, dynamic and reproducible testing conditions are required. We aimed at developing a dynamic MR-compatible cardiac left ventricle model that imitates myocardial tissue properties and simulates dynamic motion. METHODS A dynamic left ventricle silicone model was designed to match myocardial T(1) and T(2) relaxation times. Silicone mixtures were explored to replicate T(2) values of myocardial edema. A controllable piston pump was constructed to produce pulsatile flow paradigms. They were validated against flow sensors and MR data, including SSFP-based and phase-contrast-based sequences. A dedicated software interface was developed for the control. RESULTS Model dimensions represented cardiac left ventricle dimensions of healthy men. The range of end diastolic volumes was 85-175 ml, depending on the driven stroke volume. Stroke volume quantification for flow paradigms of 30∕60∕90∕120 ml resulted in 29.2∕57.6∕88.8∕118.4 ml by MR volumetry, 29.6∕59.9∕89.4∕119.0 ml by phase contrast measurements, and 29.9∕60.4∕91.1∕120.9 ml by flow meter revealing consistency. The system accurately replicated physiological and pathophysiological flow paradigms. The silicon model exhibited T(1) of 1002 ± 8 ms, T(2) of 58 ± 1 ms. Signal intensities (a.u.) of the ventricle model were 128 ± 23 for FGRE (vs 138 ± 17 in vivo) and 1156 ± 37 for b-SSFP (vs 991 ± 96 in vivo). T(2) of 75 ± 2 ms was achieved for the myocardial pathology. CONCLUSIONS We developed a controllable left ventricle model resembling MR signal characteristics of human myocardium, including pathological conditions, and allowing for the replication of contraction and flow paradigms.
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Affiliation(s)
- Matthias A Dieringer
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck Center for Molecular Medicine, Berlin 13125, Germany.
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31
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Carlsson M, Andersson R, Bloch KM, Steding-Ehrenborg K, Mosén H, Stahlberg F, Ekmehag B, Arheden H. Cardiac output and cardiac index measured with cardiovascular magnetic resonance in healthy subjects, elite athletes and patients with congestive heart failure. J Cardiovasc Magn Reson 2012; 14:51. [PMID: 22839436 PMCID: PMC3419124 DOI: 10.1186/1532-429x-14-51] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2012] [Accepted: 07/04/2012] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Cardiovascular Magnetic Resonance (CMR) enables non-invasive quantification of cardiac output (CO) and thereby cardiac index (CI, CO indexed to body surface area). The aim of this study was to establish if CI decreases with age and compare the values to CI for athletes and for patients with congestive heart failure (CHF). METHODS CI was measured in 144 healthy volunteers (39 ± 16 years, range 21-81 years, 68 females), in 60 athletes (29 ± 6 years, 30 females) and in 157 CHF patients with ejection fraction (EF) below 40% (60 ± 13 years, 33 females). CI was calculated using aortic flow by velocity-encoded CMR and is presented as mean ± SD. Flow was validated in vitro using a flow phantom and in 25 subjects with aorta and pulmonary flow measurements. RESULTS There was a slight decrease of CI with age in healthy subjects (8 ml/min/m² per year, r² = 0.07, p = 0.001). CI in males (3.2 ± 0.5 l/min/m²) and females (3.1 ± 0.4 l/min/m²) did not differ (p = 0.64). The mean ± SD of CI in healthy subjects in the age range of 20-29 was 3.3 ± 0.4 l/min/m², in 30-39 years 3.3 ± 0.5 l/min/m², in 40-49 years 3.1 ± 0.5 l/min/m², 50-59 years 3.0 ± 0.4 l/min/m² and >60 years 3.0 ± 0.4 l/min/m². There was no difference in CI between athletes and age-controlled healthy subjects but HR was lower and indexed SV higher in athletes. CI in CHF patients (2.3 ± 0.6 l/min/m²) was lower compared to the healthy population (p < 0.001). There was a weak correlation between CI and EF in CHF patients (r² = 0.07, p < 0.001) but CI did not differ between patients with NYHA-classes I-II compared to III-IV (n = 97, p = 0.16) or patients with or without hospitalization in the previous year (n = 100, p = 0.72). In vitro phantom validation showed low bias (-0.8 ± 19.8 ml/s) and in vivo validation in 25 subjects also showed low bias (0.26 ± 0.61 l/min, QP/QS 1.04 ± 0.09) between pulmonary and aortic flow. CONCLUSIONS CI decreases in healthy subjects with age but does not differ between males and females. We found no difference in CI between athletes and healthy subjects at rest but CI was lower in patients with congestive heart failure. The presented values can be used as reference values for flow velocity mapping CMR.
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Affiliation(s)
- Marcus Carlsson
- Department of Clinical Physiology and Nuclear Medicine, BFC, Skåne University Hospital, Lund University, Lund, SE-22185, Sweden
| | - Ruslana Andersson
- Department of Clinical Physiology and Nuclear Medicine, BFC, Skåne University Hospital, Lund University, Lund, SE-22185, Sweden
| | - Karin Markenroth Bloch
- Philips Healthcare, Lund, Sweden
- Department of Radiation Physics, Lund University, Lund, Sweden
| | - Katarina Steding-Ehrenborg
- Department of Clinical Physiology and Nuclear Medicine, BFC, Skåne University Hospital, Lund University, Lund, SE-22185, Sweden
| | - Henrik Mosén
- Department of Clinical Physiology and Nuclear Medicine, BFC, Skåne University Hospital, Lund University, Lund, SE-22185, Sweden
| | | | - Bjorn Ekmehag
- Norrtalje Hospital, TioHundra AB, Norrtalje, Sweden and Lund University, Lund, Sweden
| | - Hakan Arheden
- Department of Clinical Physiology and Nuclear Medicine, BFC, Skåne University Hospital, Lund University, Lund, SE-22185, Sweden
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Evaluation of different magnetic resonance imaging techniques for the assessment of active left atrial emptying. Eur Radiol 2012; 22:1904-11. [DOI: 10.1007/s00330-012-2460-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 02/12/2012] [Accepted: 02/23/2012] [Indexed: 11/30/2022]
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Bolen MA, Setser RM, Gabriel RS, Renapurkar RD, Tandon Y, Lieber ML, Desai MY, Flamm SD. Effect of protocol choice on phase contrast cardiac magnetic resonance flow measurement in the ascending aorta: breath-hold and non-breath-hold. Int J Cardiovasc Imaging 2012; 29:113-20. [PMID: 22527258 DOI: 10.1007/s10554-012-0047-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 03/27/2012] [Indexed: 10/28/2022]
Abstract
Flow assessment with phase contrast magnetic resonance imaging (PC-MRI) protocols is an important component of a comprehensive cardiovascular MR (CMR) assessment. Breath-hold (BH) and non-breath-hold (NBH) PC-MRI protocols are widely available for this imaging modality. Because flow in the great vessels is known to vary with the respiratory cycle, we hypothesized that these 2 approaches might yield different results in the clinical assessment of forward and regurgitant flow in the ascending aorta. Further, given renewed awareness of the possible effect of velocity offsets in PC-MRI, we also sought to evaluate the impact of BH and NBH protocols on this potential source of error. A prospective observational study was performed in 55 consecutive patients referred for clinical CMR of the thoracic aorta. Both BH and NBH protocols were performed at the sinotubular junction and at the mid ascending aorta. Ten additional patients underwent repeated scanning at the mid ascending aorta with both BH and NBH protocols so that protocol variability could be assessed. Finally, ten patients were scanned with both BH and NBH protocols, and phantoms were then imaged with identical imaging parameters so that offset errors associated with each protocol could be evaluated. Forward flow was generally greater with the NBH protocol than with the BH protocol (mean values 102.1 mL vs. 97.9 mL; P = 0.0004). The Bland-Altman limits of agreement were quite wide for all indices (e.g, forward flow, -26.7 mL, +18.2 mL), which suggests that results from BH and NBH protocols cannot be interchanged with confidence. Estimated phase offset errors were similar for both protocols and were generally within acceptable ranges at the mid ascending level, with slightly higher values observed at the sinotubular junction for the BH technique. We observed differences in flow values with BH and NBH protocols for PC-MRI. This finding is relevant to patients imaged serially for the evaluation of cardiac output or valve (aortic or mitral) insufficiency, for whom adherence to one PC-MRI breathing protocol is likely most effective.
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Affiliation(s)
- Michael A Bolen
- Imaging Institute, Cleveland Clinic, 9500 Euclid Avenue, J1-4, Cleveland, OH 44195, USA.
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Espe EKS, Aronsen JM, Skrbic B, Skulberg VM, Schneider JE, Sejersted OM, Zhang L, Sjaastad I. Improved MR phase-contrast velocimetry using a novel nine-point balanced motion-encoding scheme with increased robustness to eddy current effects. Magn Reson Med 2012; 69:48-61. [PMID: 22392844 DOI: 10.1002/mrm.24226] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 01/17/2012] [Accepted: 02/04/2012] [Indexed: 01/23/2023]
Abstract
Phase-contrast MRI (PC-MRI) velocimetry is a noninvasive, high-resolution motion assessment tool. However, high motion sensitivity requires strong motion-encoding magnetic gradients, making phase-contrast-MRI prone to baseline shift artifacts due to the generation of eddy currents. In this study, we propose a novel nine-point balanced velocity-encoding strategy, designed to be more accurate in the presence of strong and rapidly changing gradients. The proposed method was validated using a rotating phantom, and its robustness and precision were explored and compared with established approaches through computer simulations and in vivo experiments. Computer simulations yielded a 39-57% improvement in velocity-noise ratio (corresponding to a 27-33% reduction in measurement error), depending on which method was used for comparison. Moreover, in vivo experiments confirmed this by demonstrating a 26-53% reduction in accumulated velocity error over the R-R interval. The nine-point balanced phase-contrast-MRI-encoding strategy is likely useful for settings where high spatial and temporal resolution and/or high motion sensitivity is required, such as in high-resolution rodent myocardial tissue phase mapping.
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Affiliation(s)
- Emil K S Espe
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.
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35
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Carlsson M, Heiberg E, Toger J, Arheden H. Quantification of left and right ventricular kinetic energy using four-dimensional intracardiac magnetic resonance imaging flow measurements. Am J Physiol Heart Circ Physiol 2011; 302:H893-900. [PMID: 22180653 DOI: 10.1152/ajpheart.00942.2011] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We aimed to quantify kinetic energy (KE) during the entire cardiac cycle of the left ventricle (LV) and right ventricle (RV) using four-dimensional phase-contrast magnetic resonance imaging (MRI). KE was quantified in healthy volunteers (n = 9) using an in-house developed software. Mean KE through the cardiac cycle of the LV and the RV were highly correlated (r(2) = 0.96). Mean KE was related to end-diastolic volume (r(2) = 0.66 for LV and r(2) = 0.74 for RV), end-systolic volume (r(2) = 0.59 and 0.68), and stroke volume (r(2) = 0.55 and 0.60), but not to ejection fraction (r(2) < 0.01, P = not significant for both). Three KE peaks were found in both ventricles, in systole, early diastole, and late diastole. In systole, peak KE in the LV was lower (4.9 ± 0.4 mJ, P = 0.004) compared with the RV (7.5 ± 0.8 mJ). In contrast, KE during early diastole was higher in the LV (6.0 ± 0.6 mJ, P = 0.004) compared with the RV (3.6 ± 0.4 mJ). The late diastolic peaks were smaller than the systolic and early diastolic peaks (1.3 ± 0.2 and 1.2 ± 0.2 mJ). Modeling estimated the proportion of KE to total external work, which comprised ∼0.3% of LV external work and 3% of RV energy at rest and 3 vs. 24% during peak exercise. The higher early diastolic KE in the LV indicates that LV filling is more dependent on ventricular suction compared with the RV. RV early diastolic filling, on the other hand, may be caused to a higher degree of the return of the atrioventricular plane toward the base of the heart. The difference in ventricular geometry with a longer outflow tract in the RV compared with the LV explains the higher systolic KE in the RV.
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Affiliation(s)
- M Carlsson
- Department of Clinical Physiology, Lund University, Skane University Hospital, Lund, Sweden.
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Carlsson M, Töger J, Kanski M, Bloch KM, Ståhlberg F, Heiberg E, Arheden H. Quantification and visualization of cardiovascular 4D velocity mapping accelerated with parallel imaging or k-t BLAST: head to head comparison and validation at 1.5 T and 3 T. J Cardiovasc Magn Reson 2011; 13:55. [PMID: 21970399 PMCID: PMC3213199 DOI: 10.1186/1532-429x-13-55] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Accepted: 10/04/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Three-dimensional time-resolved (4D) phase-contrast (PC) CMR can visualize and quantify cardiovascular flow but is hampered by long acquisition times. Acceleration with SENSE or k-t BLAST are two possibilities but results on validation are lacking, especially at 3 T. The aim of this study was therefore to validate quantitative in vivo cardiac 4D-acquisitions accelerated with parallel imaging and k-t BLAST at 1.5 T and 3 T with 2D-flow as the reference and to investigate if field strengths and type of acceleration have major effects on intracardiac flow visualization. METHODS The local ethical committee approved the study. 13 healthy volunteers were scanned at both 1.5 T and 3 T in random order with 2D-flow of the aorta and main pulmonary artery and two 4D-flow sequences of the heart accelerated with SENSE and k-t BLAST respectively. 2D-image planes were reconstructed at the aortic and pulmonary outflow. Flow curves were calculated and peak flows and stroke volumes (SV) compared to the results from 2D-flow acquisitions. Intra-cardiac flow was visualized using particle tracing and image quality based on the flow patterns of the particles was graded using a four-point scale. RESULTS Good accuracy of SV quantification was found using 3 T 4D-SENSE (r2 = 0.86, -0.7 ± 7.6%) and although a larger bias was found on 1.5 T (r2 = 0.71, -3.6 ± 14.8%), the difference was not significant (p = 0.46). Accuracy of 4D k-t BLAST for SV was lower (p < 0.01) on 1.5 T (r2 = 0.65, -15.6 ± 13.7%) compared to 3 T (r2 = 0.64, -4.6 ± 10.0%). Peak flow was lower with 4D-SENSE at both 3 T and 1.5 T compared to 2D-flow (p < 0.01) and even lower with 4D k-t BLAST at both scanners (p < 0.01). Intracardiac flow visualization did not differ between 1.5 T and 3 T (p = 0.09) or between 4D-SENSE or 4D k-t BLAST (p = 0.85). CONCLUSIONS The present study showed that quantitative 4D flow accelerated with SENSE has good accuracy at 3 T and compares favourably to 1.5 T. 4D flow accelerated with k-t BLAST underestimate flow velocities and thereby yield too high bias for intra-cardiac quantitative in vivo use at the present time. For intra-cardiac 4D-flow visualization, however, 1.5 T and 3 T as well as SENSE or k-t BLAST can be used with similar quality.
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Affiliation(s)
- Marcus Carlsson
- Dept. of Clinical Physiology, Lund University and Skane University Hospital, Lund, Sweden
| | - Johannes Töger
- Dept. of Clinical Physiology, Lund University and Skane University Hospital, Lund, Sweden
| | - Mikael Kanski
- Dept. of Clinical Physiology, Lund University and Skane University Hospital, Lund, Sweden
| | - Karin Markenroth Bloch
- Philips Healthcare, Lund, Sweden
- Dept. of Radiation Physics, Lund University, Lund, Sweden
| | | | - Einar Heiberg
- Dept. of Clinical Physiology, Lund University and Skane University Hospital, Lund, Sweden
| | - Håkan Arheden
- Dept. of Clinical Physiology, Lund University and Skane University Hospital, Lund, Sweden
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Pennell DJ, Firmin DN, Kilner PJ, Manning WJ, Mohiaddin RH, Prasad SK. Review of journal of cardiovascular magnetic resonance 2010. J Cardiovasc Magn Reson 2011; 13:48. [PMID: 21914185 PMCID: PMC3182946 DOI: 10.1186/1532-429x-13-48] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Accepted: 09/13/2011] [Indexed: 12/15/2022] Open
Abstract
There were 75 articles published in the Journal of Cardiovascular Magnetic Resonance (JCMR) in 2010, which is a 34% increase in the number of articles since 2009. The quality of the submissions continues to increase, and the editors were delighted with the recent announcement of the JCMR Impact Factor of 4.33 which showed a 90% increase since last year. Our acceptance rate is approximately 30%, but has been falling as the number of articles being submitted has been increasing. In accordance with Open-Access publishing, the JCMR articles go on-line as they are accepted with no collating of the articles into sections or special thematic issues. Last year for the first time, the Editors summarized the papers for the readership into broad areas of interest or theme, which we felt would be useful to practitioners of cardiovascular magnetic resonance (CMR) so that you could review areas of interest from the previous year in a single article in relation to each other and other recent JCMR articles 1. This experiment proved very popular with a very high rate of downloading, and therefore we intend to continue this review annually. The papers are presented in themes and comparison is drawn with previously published JCMR papers to identify the continuity of thought and publication in the journal. We hope that you find the open-access system increases wider reading and citation of your papers, and that you will continue to send your quality manuscripts to JCMR for publication.
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Affiliation(s)
- Dudley J Pennell
- CMR Unit Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK
- National Heart and Lung Institute, Imperial College, Exhibition Road, London, SW7 2AZ, UK
| | - David N Firmin
- CMR Unit Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK
- National Heart and Lung Institute, Imperial College, Exhibition Road, London, SW7 2AZ, UK
| | - Philip J Kilner
- CMR Unit Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK
- National Heart and Lung Institute, Imperial College, Exhibition Road, London, SW7 2AZ, UK
| | - Warren J Manning
- Department of Medicine (Cardiovascular Division) and Radiology, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215 USA
- Harvard Medical School, 25 Shattuck Street, Boston, MA 02115 USA
| | - Raad H Mohiaddin
- CMR Unit Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK
- National Heart and Lung Institute, Imperial College, Exhibition Road, London, SW7 2AZ, UK
| | - Sanjay K Prasad
- CMR Unit Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK
- National Heart and Lung Institute, Imperial College, Exhibition Road, London, SW7 2AZ, UK
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Jorstig SH, Kähäri A, Emilsson K, Thunberg P. Calculation of right ventricular stroke volume in short-axis MR images using the equation of the tricuspid plane. Clin Physiol Funct Imaging 2011; 32:5-11. [DOI: 10.1111/j.1475-097x.2011.01047.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Giese D, Haeberlin M, Barmet C, Pruessmann KP, Schaeffter T, Kozerke S. Analysis and correction of background velocity offsets in phase-contrast flow measurements using magnetic field monitoring. Magn Reson Med 2011; 67:1294-302. [PMID: 21826731 DOI: 10.1002/mrm.23111] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 06/06/2011] [Accepted: 06/27/2011] [Indexed: 11/11/2022]
Abstract
The value of phase-contrast magnetic resonance imaging for quantifying tissue motion and blood flow has been long recognized. However, the sensitivity of the method to system imperfections can lead to inaccuracies limiting its clinical acceptance. A key source of error relates to eddy current-induced phase fluctuations, which can offset the measured object velocity significantly. A higher-order dynamic field camera was used to study the spatiotemporal evolution of background phases in cine phase-contrast measurements. It is demonstrated that eddy current-induced offsets in phase-difference data are present up to the second spatial order. Oscillatory temporal behaviors of offsets in the kHz range suggest mechanical resonances of the MR system to be non-negligible in phase-contrast imaging. By careful selection of the echo time, their impact can be significantly reduced. When applying field monitoring data for correcting eddy current and mechanically induced velocity offsets, errors decrease to less than 0.5% of the maximum velocity for various sequence settings proving the robustness of the correction approach. In vivo feasibility is demonstrated for aortic and pulmonary flow measurements in five healthy subjects. Using field monitoring data, mean error in stroke volume was reduced from 10% to below 3%.
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Affiliation(s)
- Daniel Giese
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland.
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