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Correia de Verdier M, Berglund J, Wikström J. Effect of MRI acquisition parameters on accuracy and precision of phase-contrast measurements in a small-lumen vessel phantom. Eur Radiol Exp 2024; 8:45. [PMID: 38472565 DOI: 10.1186/s41747-024-00435-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 01/12/2024] [Indexed: 03/14/2024] Open
Abstract
BACKGROUND Phase-contrast magnetic resonance imaging (PC-MRI) quantifies blood flow and velocity noninvasively. Challenges arise in neurovascular disorders due to small vessels. We evaluated the impact of voxel size, number of signal averages (NSA), and velocity encoding (VENC) on PC-MRI measurement accuracy and precision in a small-lumen vessel phantom. METHODS We constructed an in vitro model with a constant flow rate using a 2.2-mm inner diameter plastic tube. A reservoir with a weight scale and timer was used as standard reference. Gradient-echo T1 weighted PC-MRI sequence was performed on a 3-T scanner with varying voxel size (2.5, 5.0, 7.5 mm3), NSA (1, 2, 3), and VENC (200, 300, 400 cm/s). We repeated measurements nine times per setting, calculating mean flow rate, maximum velocity, and least detectable difference (LDD). RESULTS PC-MRI flow measurements were higher than standard reference values (mean ranging from 7.3 to 9.5 mL/s compared with 6.6 mL/s). Decreased voxel size improved accuracy, reducing flow rate measurements from 9.5 to 7.3 mL/s. The LDD for flow rate and velocity varied between 1 and 5%. The LDD for flow rate decreased with increased voxel size and NSA (p = 0.033 and 0.042). The LDD for velocity decreased with increased voxel size (p < 10-16). No change was observed when VENC varied. CONCLUSIONS PC-MRI overestimated flow. However, it has high precision in a small-vessel phantom with constant flow rate. Improved accuracy was obtained with increasing spatial resolution (smaller voxels). Improved precision was obtained with increasing signal-to-noise ratio (larger voxels and/or higher NSA). RELEVANCE STATEMENT Phase-contrast MRI is clinically used in large vessels. To further investigate the possibility of using phase-contrast MRI for smaller intracranial vessels in neurovascular disorders, we need to understand how acquisition parameters affect phase-contrast MRI-measured flow rate and velocity in small vessels. KEY POINTS • PC-MRI measures flow and velocity in a small lumen phantom with high precision but overestimates flow rate. • The precision of PC-MRI measurements matches the precision of standard reference for flow rate measurements. • Optimizing PC-MRI settings can enhance accuracy and precision in flow rate and velocity measurements.
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Affiliation(s)
- Maria Correia de Verdier
- Department of Surgical Sciences, Section of Neuroradiology, Uppsala University, Uppsala, Sweden.
| | - Johan Berglund
- Department of Surgical Sciences, Section of Molecular Imaging and Medical Physics, Uppsala University, Uppsala, Sweden
| | - Johan Wikström
- Department of Surgical Sciences, Section of Neuroradiology, Uppsala University, Uppsala, Sweden
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Terada M, Takehara Y, Isoda H, Wakayama T, Nozaki A. Technical Background for 4D Flow MR Imaging. Magn Reson Med Sci 2022; 21:267-277. [PMID: 35153275 PMCID: PMC9680548 DOI: 10.2463/mrms.rev.2021-0104] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 11/20/2021] [Indexed: 10/27/2023] Open
Abstract
Recently, the hemodynamic assessments with 3D cine phase-contrast (PC) MRI (4D flow MRI) have attracted considerable attention from clinicians. Unlike 2D cine PC MRI, the technique allows for cardiac phase-resolved data acquisitions of flow velocity vectors within the entire FOV during a clinically viable period. Thus, the method has enabled retrospective flowmetry in the spatial and temporal axes, which are essential to derive hemodynamic parameters related to vascular homeostasis and those to the progression of the pathologies. Accelerations in imaging are critical for this technology to be clinically viable; however, a high SNR or velocity-to-noise ratio (VNR) is also vital for accurate flow measurements. In this chapter, the technologies enabling this difficult balance are discussed.
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Affiliation(s)
- Masaki Terada
- Department of Diagnostic Radiologic Technology, Iwata City Hospital, Iwata, Shizuoka, Japan
| | - Yasuo Takehara
- Department of Fundamental Development for Advanced Low Invasive Diagnostic Imaging, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Haruo Isoda
- Department of Brain & Mind Sciences, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | | | - Atsushi Nozaki
- MR Applications and Workflow, GE Healthcare Japan, Tokyo, Japan
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Auti OB, Bandekar K, Kamat N, Raj V. Cardiac magnetic resonance techniques: Our experience on wide bore 3 tesla magnetic resonance system. Indian J Radiol Imaging 2021; 27:404-412. [PMID: 29379234 PMCID: PMC5761166 DOI: 10.4103/ijri.ijri_503_16] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Cardiovascular magnetic resonance (CMR) has become a widely adapted imaging modality in the diagnosis and management of patients with cardiovascular diseases. It provides unparalleled data of cardiac function and myocardial morphology. Majority of CMR imaging is currently being performed on 1.5 Tesla (T) MR systems. Over the last many years, the cardiac imaging protocols have been standardized and optimized in the 1.5T systems. 3T MR systems are now being used more and more in small and large institutions in our country due to their proven advantages in the field of neuro, body, and musculoskeletal imaging. Cardiac imaging on 3T system can be a double-edged sword. On one hand, it may provide nondiagnostic images due to significant artifacts, and on the other hand, it may complete the examination in quick time and provide excellent quality images. It is therefore important for the user to be aware of the potential pitfalls of CMR in 3T systems and also the necessary steps to avoid them. In this study, we discuss various challenges and advantages of performing CMR in a 3T system. We also present potential technical solutions to improve the image quality.
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Affiliation(s)
- Onkar B Auti
- Department of Radio-diagnosis, Narayana Health City, Bengaluru, Karnataka, India.,Department of Radio-diagnosis, Jupiter Hospital, Thane, Maharashtra, India
| | - Kalashree Bandekar
- Department of Radio-diagnosis, Jupiter Hospital, Thane, Maharashtra, India
| | - Nikhil Kamat
- Department of Radio-diagnosis, Jupiter Hospital, Thane, Maharashtra, India
| | - Vimal Raj
- Department of Radio-diagnosis, Narayana Health City, Bengaluru, Karnataka, India
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Laganà MM, Jakimovski D, Bergsland N, Dwyer MG, Baglio F, Zivadinov R. Measuring Aqueduct of Sylvius Cerebrospinal Fluid Flow in Multiple Sclerosis Using Different Software. Diagnostics (Basel) 2021; 11:325. [PMID: 33671219 PMCID: PMC7923004 DOI: 10.3390/diagnostics11020325] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 02/14/2021] [Indexed: 01/02/2023] Open
Abstract
Aqueduct of Sylvius (AoS) cerebrospinal fluid flow can be quantified using phase-contrast (PC) Magnetic Resonance Imaging. The software used for AoS segmentation might affect the PC-derived measures. We analyzed AoS PC data of 30 people with multiple sclerosis and 19 normal controls using three software packages, and estimated cross-sectional area (CSA), average and highest AoS velocity (Vmean and Vmax), flow rate and volume. Our aims were to assess the repeatability and reproducibility of each PC-derived measure obtained with the various software packages, including in terms of group differentiation. All the variables had good repeatability, except the average Vmean, flow rate and volume obtained with one software package. Substantial to perfect agreement was seen when evaluating the overlap between the AoS segmentations obtained with different software packages. No variable was significantly different between software packages, with the exception of Vmean diastolic peak and CSA. Vmax diastolic peak differentiated groups, regardless of the software package. In conclusion, a clinical study should preliminarily evaluate the repeatability in order to interpret its findings. Vmax seemed to be a repeatable and reproducible measure, since the pixel with its value is usually located in the center of the AoS, and is thus unlikely be affected by ROI size.
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Affiliation(s)
| | - Dejan Jakimovski
- Buffalo Neuroimaging Analysis Center (BNAC), Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY 14203, USA; (D.J.); (M.G.D.); (R.Z.)
| | - Niels Bergsland
- IRCCS, Fondazione Don Carlo Gnocchi ONLUS, 20148 Milan, Italy; (N.B.); (F.B.)
- Buffalo Neuroimaging Analysis Center (BNAC), Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY 14203, USA; (D.J.); (M.G.D.); (R.Z.)
| | - Michael G. Dwyer
- Buffalo Neuroimaging Analysis Center (BNAC), Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY 14203, USA; (D.J.); (M.G.D.); (R.Z.)
| | - Francesca Baglio
- IRCCS, Fondazione Don Carlo Gnocchi ONLUS, 20148 Milan, Italy; (N.B.); (F.B.)
| | - Robert Zivadinov
- Buffalo Neuroimaging Analysis Center (BNAC), Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY 14203, USA; (D.J.); (M.G.D.); (R.Z.)
- Center for Biomedical Imaging at Clinical Translational Science Institute, University at Buffalo, State University of New York, Buffalo, NY 14203, USA
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Varghese J, Craft J, Crabtree CD, Liu Y, Jin N, Chow K, Ahmad R, Simonetti OP. Assessment of cardiac function, blood flow and myocardial tissue relaxation parameters at 0.35 T. NMR IN BIOMEDICINE 2020; 33:e4317. [PMID: 32363644 DOI: 10.1002/nbm.4317] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 03/27/2020] [Accepted: 04/05/2020] [Indexed: 06/11/2023]
Abstract
A low field strength (B0) system could increase cardiac MRI availability for patients otherwise contraindicated at higher field. Lower equipment costs could also broaden cardiac MR accessibility. The current study investigated the feasibility of cardiac function with steady-state free precession and flow assessment with phase contrast (PC) cine images at 0.35 T, and evaluated differences in myocardial relaxation times using quantitative T1, T2 and T2* maps by comparison with 1.5 and 3 T results in a small cohort of six healthy volunteers. Signal-to-noise ratio (SNR) differences across systems were characterized with proton density-weighted spin echo phantom data. SNR at 0.35 T was lower by factors of 5.5 and 15.0 compared with the 1.5 and 3 T systems used in this study. All cine images at 0.35 T scored 3 or greater on a five-point image quality scale. Normalized blood-myocardium contrast in cine images, left ventricular volumes (end diastolic volume, end systolic volume) and function (ejection fraction and stroke volume) measures at 0.35 T matched 1.5 and 3 T results. Phase-to-noise ratio in 0.35 T PC images (11.7 ± 1.9) was lower than 1.5 T (18.7 ± 5.2) and 3 T (44.9 ± 16.5). Peak velocity and stroke volume determined from PC images were similar across systems. Myocardial T1 increased (564 ± 13 ms at 0.35 T, 955 ± 19 ms at 1.5 T and 1200 ± 35 ms at 3 T) while T2 (59 ± 4 ms at 0.35 T, 49 ± 3 ms at 1.5 T and 40 ± 2 ms at 3 T) and T2* (42 ± 8 ms at 0.35 T, 33 ± 6 ms at 1.5 T and 24 ± 3 ms at 3 T) decreased with increasing B0. Despite SNR deficits, cardiovascular function, flow assessment and myocardial relaxation parameter mapping is feasible at 0.35 T using standard cardiovascular imaging sequences.
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Affiliation(s)
- Juliet Varghese
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Jason Craft
- Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio
- St. Francis Hospital, Roslyn, New York, USA
| | - Christopher D Crabtree
- Kinesiology, Health and Exercise Sciences, Department of Human Sciences, The Ohio State University, Columbus, Ohio
| | - Yingmin Liu
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Ning Jin
- Cardiovascular MR R&D, Siemens Medical Solutions, Columbus, Ohio
| | - Kelvin Chow
- Cardiovascular MR R&D, Siemens Medical Solutions, Chicago, Illinois
| | - Rizwan Ahmad
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio
- Department of Biomedical Engineering, The Ohio State University, Columbus, Ohio
- Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio
| | - Orlando P Simonetti
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio
- Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio
- Department of Radiology, The Ohio State University, Columbus, Ohio
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Corrado PA, Macdonald JA, François CJ, Aggarwal NR, Weinsaft JW, Wieben O. Reduced regional flow in the left ventricle after anterior acute myocardial infarction: a case control study using 4D flow MRI. BMC Med Imaging 2019; 19:101. [PMID: 31888531 PMCID: PMC6937788 DOI: 10.1186/s12880-019-0404-7] [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: 06/20/2019] [Accepted: 12/18/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Acute myocardial infarction (AMI) alters left ventricular (LV) hemodynamics, resulting in decreased global LV ejection fraction and global LV kinetic energy. We hypothesize that anterior AMI effects localized alterations in LV flow and developed a regional approach to analyze these local changes with 4D flow MRI. METHODS 4D flow cardiac magnetic resonance (CMR) data was compared between 12 anterior AMI patients (11 males; 66 ± 12yo; prospectively acquired in 2016-2017) and 19 healthy volunteers (10 males; 40 ± 16yo; retrospective from 2010 to 2011 study). The LV cavity was contoured on short axis cine steady-state free procession CMR and partitioned into three regions: base, mid-ventricle, and apex. 4D flow data was registered to the short axis segmentation. Peak systolic and diastolic through-plane flows were compared region-by-region between groups using linear models of flow with age, sex, and heart rate as covariates. RESULTS Peak systolic flow was reduced in anterior AMI subjects compared to controls in the LV mid-ventricle (fitted reduction = 3.9 L/min; P = 0.01) and apex (fitted reduction = 1.4 L/min; P = 0.02). Peak diastolic flow was also lower in anterior AMI subjects compared to controls in the apex (fitted reduction = 2.4 L/min; P = 0.01). CONCLUSIONS A regional method to analyze 4D LV flow data was applied in anterior AMI patients and controls. Anterior AMI patients had reduced regional flow relative to controls.
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Affiliation(s)
- Philip A. Corrado
- Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Ave, Madison, WI 53705 USA
| | - Jacob A. Macdonald
- Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Ave, Madison, WI 53705 USA
| | - Christopher J. François
- Department of Radiology, University of Wisconsin-Madison, 600 Highland Ave, Madison, WI 53792 USA
| | - Niti R. Aggarwal
- Department of Medicine, University of Wisconsin-Madison, 600 Highland Ave, Madison, WI 53792 USA
| | - Jonathan W. Weinsaft
- Departments of Medicine and Radiology, Weill Cornell Medical College, 520 East 70th Street, Starr Pavilion, 4th Floor, New York, NY 10021 USA
| | - Oliver Wieben
- Departments of Medical Physics and Radiology, University of Wisconsin-Madison, 1111 Highland Ave, Madison, WI 53705 USA
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Ryd D, Sun L, Steding-Ehrenborg K, Bidhult S, Kording F, Ruprecht C, Macgowan CK, Seed M, Aletras AH, Arheden H, Hedström E. Quantification of blood flow in the fetus with cardiovascular magnetic resonance imaging using Doppler ultrasound gating: validation against metric optimized gating. J Cardiovasc Magn Reson 2019; 21:74. [PMID: 31783877 PMCID: PMC6883707 DOI: 10.1186/s12968-019-0586-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 10/25/2019] [Indexed: 12/15/2022] Open
Abstract
INTRODUCTION Fetal cardiovascular magnetic resonance (CMR) imaging is used clinically and for research, but has been previously limited due to lack of direct gating methods. A CMR-compatible Doppler ultrasound (DUS) gating device has resolved this. However, the DUS-gating method is not validated against the current reference method for fetal phase-contrast blood flow measurements, metric optimized gating (MOG). Further, we investigated how different methods for vessel delineation affect flow volumes and observer variability in fetal flow acquisitions. AIMS To 1) validate DUS gating versus MOG for quantifying fetal blood flow; 2) assess repeatability of DUS gating; 3) assess impact of region of interest (ROI) size on flow volume; and 4) compare time-resolved and static delineations for flow volume and observer variability. METHODS Phase-contrast CMR was acquired in the fetal descending aorta (DAo) and umbilical vein by DUS gating and MOG in 22 women with singleton pregnancy in gestational week 360 (265-400) with repeated scans in six fetuses. Impact of ROI size on measured flow was assessed for ROI:s 50-150% of the vessel diameter. Four observers from two centers provided time-resolved and static delineations. Bland-Altman analysis was used to determine agreement between both observers and methods. RESULTS DAo flow was 726 (348-1130) ml/min and umbilical vein flow 366 (150-782) ml/min by DUS gating. Bias±SD for DUS-gating versus MOG were - 45 ± 122 ml/min (-6 ± 15%) for DAo and 19 ± 136 ml/min (2 ± 24%) for umbilical vein flow. Repeated flow measurements in the same fetus showed similar volumes (median CoV = 11% (DAo) and 23% (umbilical vein)). Region of interest 50-150% of vessel diameter yielded flow 35-120%. Bias±SD for time-resolved versus static DUS-gated flow was 33 ± 39 ml/min (4 ± 6%) for DAo and 11 ± 84 ml/min (2 ± 15%) for umbilical vein flow. CONCLUSIONS Quantification of blood flow in the fetal DAo and umbilical vein using DUS-gated phase-contrast CMR is feasible and agrees with the current reference method. Repeatability was generally high for CMR fetal blood flow assessment. An ROI similar to the vessel area or slightly larger is recommended. A static ROI is sufficient for fetal flow quantification using currently available CMR sequences.
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Affiliation(s)
- Daniel Ryd
- Clinical Physiology, Department of Clinical Sciences Lund, Lund University, Skane University Hospital, Lund, Sweden
| | - Liqun Sun
- Department of Pediatrics, University of Toronto and Hospital for Sick Children, Toronto, ON Canada
| | - Katarina Steding-Ehrenborg
- Clinical Physiology, Department of Clinical Sciences Lund, Lund University, Skane University Hospital, Lund, Sweden
- Department of Health Sciences, Physiotherapy, Lund University, Lund, Sweden
| | - Sebastian Bidhult
- Clinical Physiology, Department of Clinical Sciences Lund, Lund University, Skane University Hospital, Lund, Sweden
- Department of Biomedical Engineering, Faculty of Engineering, Lund University, Lund, Sweden
| | - Fabian Kording
- Department of Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christian Ruprecht
- Department of Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christopher K. Macgowan
- Department of Medical Biophysics, University of Toronto and Hospital for Sick Children, Toronto, ON Canada
| | - Michael Seed
- Department of Pediatrics, University of Toronto and Hospital for Sick Children, Toronto, ON Canada
- Department of Diagnostic Imaging, University of Toronto and Hospital for Sick Children, Toronto, ON Canada
| | - Anthony H. Aletras
- Clinical Physiology, Department of Clinical Sciences Lund, Lund University, Skane University Hospital, Lund, Sweden
- School of Medicine, Laboratory of Computing, Medical Informatics and Biomedical, Imaging Technologies, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Håkan Arheden
- Clinical Physiology, Department of Clinical Sciences Lund, Lund University, Skane University Hospital, Lund, Sweden
| | - Erik Hedström
- Clinical Physiology, Department of Clinical Sciences Lund, Lund University, Skane University Hospital, Lund, Sweden
- Diagnostic Radiology, Department of Clinical Sciences Lund, Lund University, Skane University Hospital, Lund, Sweden
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Long J, Lin H, Cao G, Wang MZ, Huang XJ, Xia J, Sun Z. Relationship between intracranial pressure and phase-contrast cine MRI-derived measures of cerebrospinal fluid parameters in communicating hydrocephalus. Quant Imaging Med Surg 2019; 9:1413-1420. [PMID: 31559170 DOI: 10.21037/qims.2019.08.04] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Background To explore the correlation between intracranial pressure (ICP) and cerebrospinal fluid (CSF) parameters assessed by phase-contrast cine MRI (PC-MRI). Methods Fifteen normal people and 80 subjects with communicating hydrocephalus who underwent PC-MRI examinations from a single center were included in this cross-sectional study. In addition to recording patient's age, heart rate, blood pressure and body mass index (BMI), ICP and CSF hemodynamic parameters, such as flow velocity and aqueduct diameter, were measured for correlation analysis. Results The mean ICP and CSF aqueduct diameter in hydrocephalus patients were 151.05 mmH2O and 2.877 mm, respectively, and the maximum (6.938 cm/s) and mean (0.845 cm/s) CSF flow velocities were significantly higher in these patients compared with the controls (P<0.05). After adjusting for age, heart rate, blood pressure, and BMI, there was no significant relationship between peak velocity and ICP (P>0.05). Furthermore, a nonlinear relationship was observed between the ICP and the average velocity of CSF, and the ICP and aqueduct diameter. The ICP increased with the average velocity above 1.628 cm/s (P≤0.01), and the aqueduct diameter increased more than 3.6 mm (P<0.001). Conclusions This study found significant correlations between ICP and average velocity and aqueduct diameter. These findings can be useful in assisting clinicians in predicting ICP more effectively, thus improving patient management.
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Affiliation(s)
- Jia Long
- Department of Radiology, The First Affiliated Hospital of Shenzhen University/Shenzhen Second People's Hospital, Shenzhen University Health Science Center, Shenzhen 518035, China
| | - Hai Lin
- Department of Neurosurgery, The First Affiliated Hospital of Shenzhen University/Shenzhen Second People's Hospital, Shenzhen University Health Science Center, Shenzhen 518035, China
| | - Gan Cao
- Department of Radiology, Shenzhen Second People's Hospital, Clinical Medicine College of Anhui Medical University, Shenzhen 518000, China
| | - Meng-Zhu Wang
- MR Scientific Marketing, Siemens Healthineers, Guangzhou 510145, China
| | - Xian-Jian Huang
- Department of Neurosurgery, The First Affiliated Hospital of Shenzhen University/Shenzhen Second People's Hospital, Shenzhen University Health Science Center, Shenzhen 518035, China
| | - Jun Xia
- Department of Radiology, The First Affiliated Hospital of Shenzhen University/Shenzhen Second People's Hospital, Shenzhen University Health Science Center, Shenzhen 518035, China
| | - Zhonghua Sun
- Discipline of Medical Radiation Sciences, School of Molecular and Life Sciences, Curtin University, Perth, WA, Australia
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Ebel S, Hübner L, Köhler B, Kropf S, Preim B, Jung B, Grothoff M, Gutberlet M. Validation of two accelerated 4D flow MRI sequences at 3 T: a phantom study. Eur Radiol Exp 2019; 3:10. [PMID: 30806827 PMCID: PMC6391502 DOI: 10.1186/s41747-019-0089-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 02/01/2019] [Indexed: 12/15/2022] Open
Abstract
Background Four-dimensional (4D) flow magnetic resonance imaging (MRI) sequences with advanced parallel imaging have the potential to reduce scan time with equivalent image quality and accuracy compared with standard two-dimensional (2D) flow MRI. We compared 4D flow to standard 2D flow sequences using a constant and pulsatile flow phantom at 3 T. Methods Two accelerated 4D flow sequences (GRAPPA2 and k-t-GRAPPA5) were evaluated regarding the concordance of flow volumes, flow velocities, and reproducibility as well as dependency on measuring plane and velocity encoding (Venc). The calculated flow volumes and peak velocities of the phantom were used as reference standard. Flow analysis was performed using the custom-made software “Bloodline”. Results No significant differences in flow volume were found between the 2D, both 4D flow MRI sequences, and the pump reference (p = 0.994) or flow velocities (p = 0.998) in continuous and pulsatile flow. An excellent correlation (R = 0.99–1.0) with a reference standard and excellent reproducibility of measurements (R = 0.99) was achieved for all sequences. A Venc overestimated by up to two times had no impact on flow measurements. However, misaligned measuring planes led to an increasing underestimation of flow volume and mean velocity in 2D flow accuracy, while both 4D flow measurements were not affected. Scan time was significantly shorter for k-t-GRAPPA5 (1:54 ± 0:01 min, mean ± standard deviation) compared to GRAPPA2 (3:56 ± 0:02 min) (p = 0.002). Conclusions Both 4D flow sequences demonstrated equal agreement with 2D flow measurements, without impact of Venc overestimation and plane misalignment. The highly accelerated k-t-GRAPPA5 sequence yielded results similar to those of GRAPPA2.
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Affiliation(s)
- Sebastian Ebel
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig Strümpellstrasse 39, 04289, Leipzig, Germany.
| | - Lisa Hübner
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig Strümpellstrasse 39, 04289, Leipzig, Germany
| | - Benjamin Köhler
- Department of Simulations and Graphics, University of Magdeburg, Magdeburg, Germany
| | - Siegfried Kropf
- Institute for Biometrics and Medical Informatics, University of Magdeburg, Magdeburg, Germany
| | - Bernhard Preim
- Department of Simulations and Graphics, University of Magdeburg, Magdeburg, Germany
| | - Bernd Jung
- Department of Diagnostic, Interventional and Paediatric Radiology, University of Bern, Bern, Switzerland
| | - Matthias Grothoff
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig Strümpellstrasse 39, 04289, Leipzig, Germany
| | - Matthias Gutberlet
- Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig Strümpellstrasse 39, 04289, Leipzig, Germany
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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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Loecher M, Ennis DB. Velocity reconstruction with nonconvex optimization for low-velocity-encoding phase-contrast MRI. Magn Reson Med 2017; 80:42-52. [PMID: 29130519 DOI: 10.1002/mrm.26997] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 10/13/2017] [Accepted: 10/16/2017] [Indexed: 11/09/2022]
Abstract
PURPOSE To introduce and demonstrate a nonconvex optimization method for reconstructing velocity data from low-velocity-encoding (Venc ) phase-contrast MRI data. THEORY AND METHODS Solving for velocity values from phase-contrast MRI data was formulated as a nonconvex optimization problem. Weighting was added to account for intravoxel dephasing, and a Laplacian-based regularization was used to account for residual velocity aliasing. The reconstruction was tested with two low-Venc schemes: dual-Venc and a multidirectional high-moment encoding. The reconstruction method was tested in a digital simulation, in flow phantoms, and in healthy volunteers (N = 5). RESULTS The nonconvex-optimization reconstruction velocity error was lower than the conventional reconstruction in simulations (4.6 versus 3.0 cm/s for multidirectional high moment, 8.3 versus 3.8 cm/s for dual-Venc ) and in flow phantoms (23.9 versus 5.9 cm/s for multidirectional high moment, 15.2 versus 6.4 cm/s for dual-Venc ). Qualitative assessment of velocity fields in all experiments, including healthy volunteers, showed decreased apparent noise in the velocity fields and fewer phase wraps. No additional velocity bias in measured velocities was seen in volunteers with the proposed method. CONCLUSIONS The proposed nonconvex-optimization reconstruction method incorporates additional information to solve for velocities when using any type of low-Venc (high-moment) acquisition. The method reduces the amount of residual phase aliasing, and decreases velocity errors that result from intravoxel dephasing. These improvements allow for more robust acquisitions, and for Venc to be lowered 2 to 4 times relative to conventional acquisitions, thereby increasing the velocity-to-noise ratio. Magn Reson Med, 2017. © 2017 International Society for Magnetic Resonance in Medicine. Magn Reson Med 80:42-52, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Michael Loecher
- Department of Radiological Sciences, University of California, Los Angeles, California, USA
| | - Daniel B Ennis
- Department of Radiological Sciences, University of California, Los Angeles, California, USA.,Department of Biomedical Physics IDP, University of California, Los Angeles, California, USA
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12
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Four-Dimensional Phase Contrast Magnetic Resonance Imaging Protocol Optimization Using Patient-Specific 3-Dimensional Printed Replicas for In Vivo Imaging Before and After Flow Diverter Placement. World Neurosurg 2017. [DOI: 10.1016/j.wneu.2017.06.042] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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13
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Hessenthaler A, Gaddum NR, Holub O, Sinkus R, Röhrle O, Nordsletten D. Experiment for validation of fluid-structure interaction models and algorithms. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2017; 33:e2848. [PMID: 27813272 PMCID: PMC5600002 DOI: 10.1002/cnm.2848] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Revised: 10/22/2016] [Accepted: 10/25/2016] [Indexed: 05/30/2023]
Abstract
In this paper a fluid-structure interaction (FSI) experiment is presented. The aim of this experiment is to provide a challenging yet easy-to-setup FSI test case that addresses the need for rigorous testing of FSI algorithms and modeling frameworks. Steady-state and periodic steady-state test cases with constant and periodic inflow were established. Focus of the experiment is on biomedical engineering applications with flow being in the laminar regime with Reynolds numbers 1283 and 651. Flow and solid domains were defined using computer-aided design (CAD) tools. The experimental design aimed at providing a straightforward boundary condition definition. Material parameters and mechanical response of a moderately viscous Newtonian fluid and a nonlinear incompressible solid were experimentally determined. A comprehensive data set was acquired by using magnetic resonance imaging to record the interaction between the fluid and the solid, quantifying flow and solid motion.
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Affiliation(s)
- A. Hessenthaler
- Institute of Applied Mechanics (CE)University of StuttgartPfaffenwaldring 770569 StuttgartGermany
| | - N. R. Gaddum
- Division of Imaging Sciences and Biomedical EngineeringKing's College London, 4th Floor, Lambeth Wing St. Thomas Hospital LondonSE1 7EHUK
| | - O. Holub
- Division of Imaging Sciences and Biomedical EngineeringKing's College London, 4th Floor, Lambeth Wing St. Thomas Hospital LondonSE1 7EHUK
| | - R. Sinkus
- Division of Imaging Sciences and Biomedical EngineeringKing's College London, 4th Floor, Lambeth Wing St. Thomas Hospital LondonSE1 7EHUK
| | - O. Röhrle
- Institute of Applied Mechanics (CE)University of StuttgartPfaffenwaldring 770569 StuttgartGermany
| | - D. Nordsletten
- Division of Imaging Sciences and Biomedical EngineeringKing's College London, 4th Floor, Lambeth Wing St. Thomas Hospital LondonSE1 7EHUK
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14
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Lee JC, Branch KR, Hamilton-Craig C, Krieger EV. Evaluation of aortic regurgitation with cardiac magnetic resonance imaging: a systematic review. Heart 2017; 104:103-110. [PMID: 28822982 DOI: 10.1136/heartjnl-2016-310819] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Revised: 07/31/2017] [Indexed: 11/03/2022] Open
Abstract
This review summaries the utility, application and data supporting use of cardiac magnetic resonance imaging (CMR) to evaluate and quantitate aortic regurgitation. We systematically searched Medline and PubMed for original research articles published since 2000 that provided data on the quantitation of aortic regurgitation by CMR and identified 11 articles for review. Direct aortic measurements using phase contrast allow quantitation of volumetric flow across the aortic valve and are highly reproducible and accurate compared with echocardiography. However, this technique requires diligence in prescribing the correct imaging planes in the aorta. Volumetric analytic techniques using differences in ventricular volumes are also highly accurate but less than phase contrast techniques and only accurate when concomitant valvular disease is absent. Comparison of both aortic and ventricular data for internal data verification ensures fidelity of aortic regurgitant data. CMR data can be applied to many types of aortic valve regurgitation including combined aortic stenosis with regurgitation, congenital valve diseases and post-transcatheter valve placement. CMR also predicts those patients who progress to surgery with high overall sensitivity and specificity. Future studies of CMR in patients with aortic regurgitation to quantify the incremental benefit over echocardiography as well as prediction of cardiovascular events are warranted.
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Affiliation(s)
- James C Lee
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Kelley R Branch
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Christian Hamilton-Craig
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington, USA.,Centre for Advanced Imaging, University of Queensland, Brisbane, Queensland, Australia.,Department of Cardiology, Heart & Lung Institute, The Prince Charles Hospital, Brisbane, Queensland, Australia
| | - Eric V Krieger
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington, USA.,Seattle Adult Congenital Heart Service, University of Washington School of Medicine, Seattle, Washington, USA
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15
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Khan MA, Liu J, Tarumi T, Lawley JS, Liu P, Zhu DC, Lu H, Zhang R. Measurement of cerebral blood flow using phase contrast magnetic resonance imaging and duplex ultrasonography. J Cereb Blood Flow Metab 2017; 37:541-549. [PMID: 26873888 PMCID: PMC5381449 DOI: 10.1177/0271678x16631149] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Phase contrast magnetic resonance imaging (PC-MRI) and color-coded duplex ultrasonography (CDUS) are commonly used for measuring cerebral blood flow in the internal carotid (ICA) and vertebral arteries. However, agreement between the two methods has been controversial. Recent development of high spatial and temporal resolution blood vessel wall edge-detection and wall-tracking methods with CDUS increased the accuracy and reliability of blood vessel diameter, hence cerebral blood flow measurement. The aim of this study was to compare the improved CDUS method with 3 T PC-MRI for cerebral blood flow measurements. We found that cerebral blood flow velocity measured in the ICA was lower using PC-MRI than CDUS (left ICA: PC-MRI, 18.0 ± 4.2 vs. CDUS, 25.6 ± 8.6 cm/s; right ICA: PC-MRI, 18.5 ± 4.8 vs. CDUS, 26.6 ± 6.7 cm/s, both p < 0.01). However, ICA diameters measured using PC-MRI were larger (left ICA: PC-MRI, 4.7 ± 0.50 vs. CDUS, 4.1 ± 0.46 mm; right ICA: PC-MRI, 4.5 ± 0.49 vs. CDUS, 4.0 ± 0.45 mm, both p < 0.01). Cerebral blood flow velocity measured in the left vertebral artery with PC-MRI was also lower than CDUS, but no differences in vertebral artery diameter were observed between the methods. Dynamic changes and/or intrinsic physiological fluctuations may have caused these differences in vessel diameter and velocity measurements between the methods. However, estimation of volumetric cerebral blood flow was similar and correlated between the methods despite the presence of large individual differences. These findings support the use of CDUS for cerebral blood flow measurements in the ICA and vertebral artery.
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Affiliation(s)
- Muhammad Ayaz Khan
- 1 Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, TX, USA.,2 Department of Internal Medicine, University of Texas, Dallas, TX, USA
| | - Jie Liu
- 1 Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, TX, USA.,2 Department of Internal Medicine, University of Texas, Dallas, TX, USA
| | - Takashi Tarumi
- 1 Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, TX, USA.,2 Department of Internal Medicine, University of Texas, Dallas, TX, USA
| | - Justin Stevan Lawley
- 1 Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, TX, USA.,2 Department of Internal Medicine, University of Texas, Dallas, TX, USA
| | - Peiying Liu
- 3 Advanced Imaging Research Center, University of Texas, Dallas, TX, USA
| | - David C Zhu
- 4 Department of Radiology and Psychology, Michigan State University, East Lansing, MI, USA
| | - Hanzhang Lu
- 3 Advanced Imaging Research Center, University of Texas, Dallas, TX, USA
| | - Rong Zhang
- 1 Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, Dallas, TX, USA.,2 Department of Internal Medicine, University of Texas, Dallas, TX, USA
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16
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Coronary Endothelial Dysfunction in Women With Type 2 Diabetes Measured by Coronary Phase Contrast Flow Velocity Magnetic Resonance Imaging. J Investig Med 2016; 63:856-61. [PMID: 26230492 DOI: 10.1097/jim.0000000000000226] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The aim of this study was to determine if differences in coronary endothelial function are observed between asymptomatic women with type 2 diabetes mellitus (DM) and control subjects using coronary phase contrast flow velocity magnetic resonance imaging in response to cold pressor stress, an established endothelium-dependent vasodilatory stress. METHODS Phase contrast flow velocity imaging of the right coronary artery was performed in 7 asymptomatic premenopausal women with DM and 8 healthy female participants in response to the cold pressor test at 3 T. RESULTS There was no significant difference in percent increase in coronary flow velocity from rest to peak flow velocity between DM and control subjects (32% ± 22% vs 46% ± 17%; P = 0.11). However, percent increase in coronary flow velocity was lower in DM than in control subjects (-3% ± 14% vs 31% ± 30%; P = 0.01) during the second minute of cold pressor stress, when endothelial-mediated vasodilation should occur. CONCLUSIONS Asymptomatic women with DM demonstrate reduced coronary flow velocity during the second minute of cold pressor stress, indicating coronary endothelial dysfunction.
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17
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Normal ranges and test-retest reproducibility of flow and velocity parameters in intracranial arteries measured with phase-contrast magnetic resonance imaging. Neuroradiology 2016; 58:521-31. [PMID: 26882908 DOI: 10.1007/s00234-016-1661-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 02/02/2016] [Indexed: 10/22/2022]
Abstract
INTRODUCTION The purpose of the present study was to investigate normal ranges and test-retest reproducibility of phase-contrast MRI (PC-MRI)-measured flow and velocity parameters in intracranial arteries. METHODS Highest flow (HF), lowest flow (LF), peak systolic velocity (PSV), and end diastolic velocity (EDV) were measured at two dates in the anterior (ACA), middle (MCA), and posterior (PCA) cerebral arteries of 30 healthy volunteers using two-dimensional PC-MRI at 3 T. Least detectable difference (LDD) was calculated. RESULTS In the left ACA, HF was (mean (range, LDD)) 126 ml/min (36-312, 59 %), LF 61 ml/min (0-156, 101 %), PSV 64 cm/s (32-141, 67 %), and EDV 35 cm/s (18-55, 42 %); in the right ACA, HF was 154 ml/min (42-246, 49 %), LF 77 ml/min (0-156, 131 %), PSV 75 cm/s (26-161, 82 %), and EDV 39 cm/s (7-59, 67 %). In the left MCA, HF was 235 ml/min (126-372, 35 %), LF 116 ml/min (42-186, 48 %), PSV 90 cm/s (55-183, 39 %), and EDV 46 cm/s (20-66, 28 %); in the right MCA, HF was 238 ml/min (162-342, 44 %), LF 120 ml/min (72-216, 48 %), PSV 88 cm/s (55-141, 35 %), and EDV 45 cm/s (26-67, 23 %). In the left PCA, HF was 108 ml/min (42-168, 54 %), LF 53 ml/min (18-108, 64 %), PSV 50 cm/s (24-77, 63 %), and EDV 28 cm/s (14-40, 45 %); in the right PCA, HF was 98 ml/min (30-162, 49 %), LF 49 ml/min (12-84, 55 %), PSV 47 cm/s (27-88, 59 %), and EDV 27 cm/s (16-41, 45 %). CONCLUSION PC-MRI-measured flow and velocity parameters in the main intracranial arteries have large normal ranges. Reproducibility is highest in MCA.
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18
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Schmitter S, Schnell S, Uğurbil K, Markl M, Van de Moortele PF. Towards high-resolution 4D flow MRI in the human aorta using kt-GRAPPA and B1+ shimming at 7T. J Magn Reson Imaging 2016; 44:486-99. [PMID: 26841070 DOI: 10.1002/jmri.25164] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Accepted: 01/05/2016] [Indexed: 01/27/2023] Open
Abstract
PURPOSE To evaluate the feasibility of aortic 4D flow magnetic resonance imaging (MRI) at 7T with improved spatial resolution using kt-GRAPPA acceleration while restricting acquisition time and to address radiofrequency (RF) excitation heterogeneities with B1+ shimming. MATERIALS AND METHODS 4D flow MRI data were obtained in the aorta of eight subjects using a 16-channel transmit/receive coil array at 7T. Flow quantification and acquisition time were compared for a kt-GRAPPA accelerated (R = 5) and a standard GRAPPA (R = 2) accelerated protocol. The impact of different dynamic B1+ shimming strategies on flow quantification was investigated. Two kt-GRAPPA accelerated protocols with 1.2 × 1.2 × 1.2 mm(3) and 1.8 × 1.8 × 2.4 mm(3) spatial resolution were compared. RESULTS Using kt-GRAPPA, we achieved a 4.3-fold reduction in net acquisition time resulting in scan times of about 10 minutes. No significant effect on flow quantification was observed compared to standard GRAPPA with R = 2. Optimizing the B1+ fields for the aorta impacted significantly (P < 0.05) the flow quantification while specific B1+ settings were required for respiration navigators. The high-resolution protocol yielded similar flow quantification, but allowed the depiction of branching vessels. CONCLUSION 7T in combination with B1+ shimming allows for high-resolution 4D flow MRI acquisitions in the human aorta, while kt-GRAPPA limits total scan times without affecting flow quantification. J. Magn. Reson. Imaging 2016;44:486-499.
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Affiliation(s)
- Sebastian Schmitter
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Susanne Schnell
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Kâmil Uğurbil
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Michael Markl
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
- Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, Illinois, USA
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19
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Nayak KS, Nielsen JF, Bernstein MA, Markl M, D Gatehouse P, M Botnar R, Saloner D, Lorenz C, Wen H, S Hu B, Epstein FH, N Oshinski J, Raman SV. Cardiovascular magnetic resonance phase contrast imaging. J Cardiovasc Magn Reson 2015; 17:71. [PMID: 26254979 PMCID: PMC4529988 DOI: 10.1186/s12968-015-0172-7] [Citation(s) in RCA: 154] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 07/16/2015] [Indexed: 11/10/2022] Open
Abstract
Cardiovascular magnetic resonance (CMR) phase contrast imaging has undergone a wide range of changes with the development and availability of improved calibration procedures, visualization tools, and analysis methods. This article provides a comprehensive review of the current state-of-the-art in CMR phase contrast imaging methodology, clinical applications including summaries of past clinical performance, and emerging research and clinical applications that utilize today's latest technology.
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Affiliation(s)
- Krishna S Nayak
- Ming Hsieh Department of Electrical Engineering, University of Southern California, 3740 McClintock Ave, EEB 406, Los Angeles, California, 90089-2564, USA.
| | - Jon-Fredrik Nielsen
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.
| | | | - Michael Markl
- Department of Radiology, Northwestern University, Chicago, IL, USA.
| | - Peter D Gatehouse
- Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, London, UK.
| | - Rene M Botnar
- Cardiovascular Imaging, Imaging Sciences Division, Kings's College London, London, UK.
| | - David Saloner
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA.
| | - Christine Lorenz
- Center for Applied Medical Imaging, Siemens Corporation, Baltimore, MD, USA.
| | - Han Wen
- Imaging Physics Laboratory, National Heart Lung and Blood Institute, Bethesda, MD, USA.
| | - Bob S Hu
- Palo Alto Medical Foundation, Palo Alto, CA, USA.
| | - Frederick H Epstein
- Departments of Radiology and Biomedical Engineering, University of Virginia, Charlottesville, VA, USA.
| | - John N Oshinski
- Departments of Radiology and Biomedical Engineering, Emory University School of Medicine, Atlanta, GA, USA.
| | - Subha V Raman
- Division of Cardiovascular Medicine, The Ohio State University, Columbus, OH, USA.
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20
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Rajiah P, Bolen MA. Cardiovascular MR imaging at 3 T: opportunities, challenges, and solutions. Radiographics 2015; 34:1612-35. [PMID: 25310420 DOI: 10.1148/rg.346140048] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Although 3-T magnetic resonance (MR) imaging is well established in neuroradiology and musculoskeletal imaging, it is in the nascent stages in cardiovascular imaging applications, and there is limited literature on this topic. The primary advantage of 3 T over 1.5 T is a higher signal-to-noise ratio (SNR), which can be used as such or traded off to improve spatial or temporal resolution and decrease acquisition time. However, the actual gain in SNR is limited by other factors and modifications in sequences adapted for use at 3 T. Higher resonance frequencies result in improved spectral resolution, which is beneficial for fat suppression and spectroscopy. The higher T1 values of tissues at 3 T aid in myocardial tagging, angiography, and perfusion and delayed-enhancement sequences. However, there are substantial challenges with 3-T cardiac MR imaging, including higher magnetic field and radiofrequency inhomogeneities and susceptibility effects, which diminish image quality. Off-resonance artifacts are particularly challenging, especially with steady-state free precession sequences. These artifacts can be managed by using higher-order shimming, frequency scouts, or low repetition times. B1 inhomogeneities can be managed by using radiofrequency shimming, multitransmit coils, or adiabatic pulses. Chemical shifts are also increased at 3 T. The higher radiofrequency results in higher radiofrequency deposition power and a higher specific absorption rate. MR angiography, dynamic first-pass perfusion sequences, myocardial tagging, and MR spectroscopy are more effective at 3 T, whereas delayed-enhancement, flow quantification, and black-blood sequences are comparable at 1.5 T and 3 T. Knowledge of the relevant physics helps in identifying artifacts and modifying sequences to optimize image quality. Online supplemental material is available for this article.
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Affiliation(s)
- Prabhakar Rajiah
- From the Cardiothoracic Imaging Section, Department of Radiology, University Hospitals Case Medical Center, Case Western Reserve University School of Medicine, 11100 Euclid Ave, Cleveland, OH 44106 (P.R.); and Cardiovascular Imaging Laboratory, Imaging Institute, Cleveland Clinic Foundation, Cleveland, Ohio (M.A.B.)
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21
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Hess AT, Bissell MM, Ntusi NAB, Lewis AJM, Tunnicliffe EM, Greiser A, Stalder AF, Francis JM, Myerson SG, Neubauer S, Robson MD. Aortic 4D flow: quantification of signal-to-noise ratio as a function of field strength and contrast enhancement for 1.5T, 3T, and 7T. Magn Reson Med 2015; 73:1864-71. [PMID: 24934930 DOI: 10.1002/mrm.25317] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 04/28/2014] [Accepted: 05/22/2014] [Indexed: 01/10/2023]
Abstract
PURPOSE To investigate for the first time the feasibility of aortic four-dimensional (4D) flow at 7T, both contrast enhanced (CE) and non-CE. To quantify the signal-to-noise ratio (SNR) in aortic 4D flow as a function of field strength and CE with gadobenate dimeglumine (MultiHance). METHODS Six healthy male volunteers were scanned at 1.5T, 3T, and 7T with both non-CE and CE acquisitions. Temporal SNR was calculated. Flip angle optimization for CE 4D flow was carried out using Bloch simulations that were validated against in vivo measurements. RESULTS The 7T provided 2.2 times the SNR of 3T while 3T provided 1.7 times the SNR of 1.5T in non-CE acquisitions in the descending aorta. The SNR gains achieved by CE were 1.8-fold at 1.5T, 1.7-fold at 3T, and 1.4-fold at 7T, respectively. CONCLUSION The 7T provides a new tool to explore aortic 4D flow, yielding higher SNR that can be used to push the boundaries of acceleration and resolution. Field strength and contrast enhancement at all fields provide significant improvements in SNR.
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Affiliation(s)
- Aaron T Hess
- University of Oxford Centre for Clinical Magnetic Resonance Research, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, Oxford, United Kingdom
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22
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Peng SL, Su P, Wang FN, Cao Y, Zhang R, Lu H, Liu P. Optimization of phase-contrast MRI for the quantification of whole-brain cerebral blood flow. J Magn Reson Imaging 2015; 42:1126-33. [PMID: 25676350 DOI: 10.1002/jmri.24866] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 01/22/2015] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Whole-brain cerebral blood flow (CBF) measured by phase-contrast MRI (PC-MRI) provides an important index for brain function. This work aimed to optimize the PC-MRI imaging protocol for accurate CBF measurements. METHODS Two studies were performed on a 3 Tesla system. In Study 1 (N = 12), we optimized in-plane resolution of PC-MRI acquisition for CBF quantification by considering accuracy, precision, and scan duration. In Study 2 (N = 7), we assessed the detrimental effect of nonperpendicular imaging slice orientation on CBF quantification. Both One-way analysis of variance with repeated measurement and Friedman test were used to examine the effects of resolution and angulation on CBF quantification. Additionally, we evaluated the inter-rater reliability in PC-MRI data processing. RESULTS Our results showed that CBF measurement with 0.7 mm resolution could be overestimated by up to 13.3% when compared with 0.4 mm resolution. Moreover, CBF could also be overestimated by up to 18.8% when the slice orientation is deviated by 30° from the ideal angulation. However, within 10° of the ideal slice orientation, estimated CBF was not significantly different from each other (P = 0.23 and 0.45 for internal carotid artery and vertebral artery, respectively). Inter-rater difference was <3%. CONCLUSION For fast and accurate quantification of whole-brain CBF with PC-MRI, we recommend the use of an imaging resolution of 0.5 mm and a slice orientation that is less than 10° from vessel's axial plane.
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Affiliation(s)
- Shin-Lei Peng
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, Texas, USA.,Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan
| | - Pan Su
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, Texas, USA.,Biomedical Engineering Graduate Program, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Fu-Nien Wang
- Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan
| | - Yan Cao
- Department of Mathematical Sciences, University of Texas at Dallas, Richardson, Texas, USA
| | - Rong Zhang
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA
| | - Hanzhang Lu
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, Texas, USA.,Biomedical Engineering Graduate Program, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Peiying Liu
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, Texas, USA
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23
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Ghosn MG, Shah DJ. Important advances in technology and unique applications related to cardiac magnetic resonance imaging. Methodist Debakey Cardiovasc J 2015; 10:159-62. [PMID: 25574343 DOI: 10.14797/mdcj-10-3-159] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Cardiac magnetic resonance has become a well-established imaging modality and is considered the gold standard for myocardial tissue viability assessment and ventricular volumes quantification. Recent technological hardware and software advancements in magnetic resonance imaging technology have allowed the development of new methods that can improve clinical cardiovascular diagnosis and prognosis. The advent of a new generation of higher magnetic field scanners can be beneficial to various clinical applications. Also, the development of faster acquisition techniques have allowed mapping of the magnetic relaxation properties T1, T2, and T2* in the myocardium that can be used to quantify myocardial diffuse fibrosis, determine the presence of edema or inflammation, and measure iron within the myocardium, respectively. Another recent major advancement in CMR has been the introduction of three-dimension (3D) phase contrast imaging, also known as 4D flow. The following review discusses key advances in cardiac magnetic resonance technology and their potential to improve clinical cardiovascular diagnosis and outcomes.
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Affiliation(s)
- Mohamad G Ghosn
- Houston Methodist DeBakey Heart & Vascular Center, Houston Methodist Hospital, Houston, Texas
| | - Dipan J Shah
- Houston Methodist DeBakey Heart & Vascular Center, Houston Methodist Hospital, Houston, Texas
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Zaman A, Motwani M, Oliver JJ, Crelier G, Dobson LE, Higgins DM, Plein S, Greenwood JP. 3.0T, time-resolved, 3D flow-sensitive MR in the thoracic aorta: Impact of k-t BLAST acceleration using 8- versus 32-channel coil arrays. J Magn Reson Imaging 2014; 42:495-504. [PMID: 25447784 DOI: 10.1002/jmri.24814] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 10/11/2014] [Indexed: 11/06/2022] Open
Abstract
PURPOSE To evaluate the performance of 4D flow MR in the thoracic aorta with 8- and 32-channel coil arrays using k-t BLAST and SENSE acceleration techniques and compare this to a conventional 2D SENSE approach. MATERIALS AND METHODS Fifteen healthy subjects and eight patients underwent magnetic resonance imaging (MRI) at 3.0T using: 1) 2D SENSE phase contrast velocity mapping as the reference standard and 2) 4D-flow pulse sequences accelerated with SENSE and k-t BLAST, using both 8- and 32-channel coil arrays. Data processing was performed using GT Flow. Image quality of the magnitude images and pathline visualization were graded and mean scan times, flow, peak velocity, stroke volume, and image quality were compared between techniques. RESULTS Mean scan times were significantly lower for 4D-flow sequences accelerated with k-t BLAST compared to SENSE (5.5 vs. 25.2 min; P < 0.01). 4D k-t BLAST acquisition had greater magnitude and pathline image quality than 4D SENSE acquisition for both 32-channel and 8-channel data (P < 0.001); both 4D SENSE and 4D k-t BLAST acquisitions had significantly greater image quality when 32 channels were utilized compared to 8 (P < 0.05). On Bland-Altman analysis, all 4D flow pulse sequences showed significant agreement with the 2D SENSE reference for peak velocity measurement (P > 0.05); the lowest bias being observed with the 4D 32 channel k-t BLAST sequence. There were no significant differences in measured flow, peak velocity, or stroke volume with any of the four investigated 4D acquisition techniques compared to reference technique values (P > 0.05). In patients, there were no significant differences in flow, peak velocity, or stroke volume measurements between 32-channel 4D k-t BLAST and the reference acquisition. CONCLUSION 4D flow MR using k-t BLAST and 32 channel coils allows a reduction in total scan time while improving overall image quality compared to a standard 2D SENSE and 4D SENSE acquisitions. The use of 32 channels rather than 8 channels with the 4D k-t BLAST was also preferable in terms of image quality.
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Affiliation(s)
- Arshad Zaman
- Multidisciplinary Cardiovascular Research Centre, Division of Cardiovascular and Diabetes Research, Leeds Institute of Genetics, Health & Therapeutics, University of Leeds, Leeds, UK
| | - Manish Motwani
- Multidisciplinary Cardiovascular Research Centre, Division of Cardiovascular and Diabetes Research, Leeds Institute of Genetics, Health & Therapeutics, University of Leeds, Leeds, UK
| | - James J Oliver
- Multidisciplinary Cardiovascular Research Centre, Division of Cardiovascular and Diabetes Research, Leeds Institute of Genetics, Health & Therapeutics, University of Leeds, Leeds, UK
| | - Gerard Crelier
- Institute for Biomedical Engineering, University and ETH Zurich, Switzerland
| | - Laura E Dobson
- Multidisciplinary Cardiovascular Research Centre, Division of Cardiovascular and Diabetes Research, Leeds Institute of Genetics, Health & Therapeutics, University of Leeds, Leeds, UK
| | | | - Sven Plein
- Multidisciplinary Cardiovascular Research Centre, Division of Cardiovascular and Diabetes Research, Leeds Institute of Genetics, Health & Therapeutics, University of Leeds, Leeds, UK
| | - John P Greenwood
- Multidisciplinary Cardiovascular Research Centre, Division of Cardiovascular and Diabetes Research, Leeds Institute of Genetics, Health & Therapeutics, University of Leeds, Leeds, UK
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Terada M, Matsuyoshi K, Yamada E, Anzawa Y, Oosugi M. [Study of scan parameters using three-dimensional cine phase contrast imaging for pulmonary artery velocity measurement]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2014; 70:1219-24. [PMID: 25410327 DOI: 10.6009/jjrt.2014_jsrt_70.11.1219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Pulmonary artery flow velocity, flow volume and their derived biomarkers, such as acceleration time (AT), acceleration volume (AV) and peak velocity (PV), vary depending on the severity and type of pulmonary disease. Therefore, accurate measurements of pulmonary artery velocity are very important for assessing the severity of pulmonary disease. The purpose of this study was to optimize the imaging parameters for pulmonary artery flow velocity using 3D cine PC MR, and to evaluate AT, AV, and PV for pulmonary hypertension. We changed the flip angle (FA) and view per segment (VPS). FA influenced the signal intensity, which was calculated from the magnitude images. Smaller VPS improved the accuracy of PV. Consequently, optimal setting of FA and VPS was important for hemodynamic analysis. We established the optimal FA and VPS for use in the hemodynamic analysis. AV and PV at the right pulmonary artery differed significantly between healthy volunteers and patients with pulmonary hypertension. Hemodynamic analysis of 3D cine PC MR imaging was considered promising for the evaluation of pulmonary disease.
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Jiang J, Kokeny P, Ying W, Magnano C, Zivadinov R, Mark Haacke E. Quantifying errors in flow measurement using phase contrast magnetic resonance imaging: comparison of several boundary detection methods. Magn Reson Imaging 2014; 33:185-93. [PMID: 25460329 DOI: 10.1016/j.mri.2014.10.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 10/12/2014] [Accepted: 10/13/2014] [Indexed: 10/24/2022]
Abstract
Quantifying flow from phase-contrast MRI (PC-MRI) data requires that the vessels of interest be segmented. The estimate of the vessel area will dictate the type and magnitude of the error sources that affect the flow measurement. These sources of errors are well understood, and mathematical expressions have been derived for them in previous work. However, these expressions contain many parameters that render them difficult to use for making practical error estimates. In this work, some realistic assumptions were made that allow for the simplification of such expressions in order to make them more useful. These simplified expressions were then used to numerically simulate the effect of segmentation accuracy and provide some criteria that if met, would keep errors in flow quantification below 10% or 5%. Four different segmentation methods were used on simulated and phantom MRA data to verify the theoretical results. Numerical simulations showed that including partial volumed edge pixels in vessel segmentation provides less error than missing them. This was verified with MRA simulations, as the best performing segmentation method generally included such pixels. Further, it was found that to obtain a flow error of less than 10% (5%), the vessel should be at least 4 (5) pixels in diameter, have an SNR of at least 10:1 and have a peak velocity to saturation cut-off velocity ratio of at least 5:3.
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Affiliation(s)
- Jing Jiang
- Department of Biomedical Engineering, Wayne State University, Detroit, MI, USA; Department of Radiology, Wayne State University, Detroit, MI, USA
| | - Paul Kokeny
- Department of Biomedical Engineering, Wayne State University, Detroit, MI, USA; Magnetic Resonance Innovations, Inc., Detroit, MI, USA
| | - Wang Ying
- Department of Biomedical Engineering, Wayne State University, Detroit, MI, USA; College of Information Science and Engineering, Northeastern University, Shenyang, Liaoning province, China
| | - Chris Magnano
- Buffalo Neuroimaging Analysis Center, State University of New York, Buffalo, NY, USA
| | - Robert Zivadinov
- Buffalo Neuroimaging Analysis Center, State University of New York, Buffalo, NY, USA
| | - E Mark Haacke
- Department of Biomedical Engineering, Wayne State University, Detroit, MI, USA; Department of Radiology, Wayne State University, Detroit, MI, USA; Magnetic Resonance Innovations, Inc., Detroit, MI, USA; Department of Electrical and Computer Engineering, McMaster University, Hamilton, Ontario, Canada.
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2D phase contrast blood flow velocity measurements of the thoracic vasculature: comparison of the effect of gadofosveset trisodium and gadopentetate dimeglumine. Int J Cardiovasc Imaging 2014; 31:409-16. [PMID: 25385264 DOI: 10.1007/s10554-014-0565-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2014] [Accepted: 10/31/2014] [Indexed: 10/24/2022]
Abstract
The aim of this prospective study is to compare the performance of 2D time-resolved phase-contrast (PC) MRI prior to and after the administration of an intravascular (gadofosveset-trisodium) and extravascular (gadopentetate-dimeglumine) contrast agent in the same patient in the cardiovascular system. This study was approved by the ethics committee (Study-Number-07/Q0704/2) and registered with the MedicinesAndHealthcareProductsRegulatoryAgency (MHRA-Study-Number-28482/0002/001-0001, EudraCT-Number-2006-007042). All patients signed an informed consent. 20 patients were examined using a 1.5T MR-scanner and 32-channel-coil-technology. Gadopentetate-dimeglumine (GdD) and gadofosveset-trisodium (GdT) were administered in the same patient on consecutive days. Image quality, velocity-to-noise-ratios (VNRs) and standard-deviation of blood-flow-velocities (phase-noise) were compared between GdT, GdD and non-contrast-enhanced imaging. On both days pre- and post-contrast-scans were performed. The administration of GdT significantly improved the delineation of the perfused lumen and the VNR compared to GdD and non-contrast-enhanced imaging. Standard deviations of through-plane and in-plane velocity-measurements (phase-noise) were significantly reduced after GdT administration (p < 0.05). No significant differences (p > 0.05) were measured regarding absolute flow values prior to and after the administration of GdD and GdT. PC flow imaging benefits from the administration of an intravascular contrast agent by improving the delineation of the perfused lumen and reducing phase noise in flow measurements.
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Yamasaki Y, Nagao M, Yamamura K, Yonezawa M, Matsuo Y, Kawanami S, Kamitani T, Higuchi K, Sakamoto I, Shiokawa Y, Yabuuchi H, Honda H. Quantitative assessment of right ventricular function and pulmonary regurgitation in surgically repaired tetralogy of Fallot using 256-slice CT: comparison with 3-Tesla MRI. Eur Radiol 2014; 24:3289-99. [DOI: 10.1007/s00330-014-3344-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Revised: 06/24/2014] [Accepted: 07/11/2014] [Indexed: 10/24/2022]
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29
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Speiser U, Quick S, Haas D, Youssef A, Waessnig NK, Ibrahim K, Strasser RH, Schoen S. 3-T magnetic resonance for determination of aortic valve area: A comparison to echocardiography. SCAND CARDIOVASC J 2014; 48:176-83. [DOI: 10.3109/14017431.2014.906646] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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30
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Joseph A, Kowallick JT, Merboldt KD, Voit D, Schaetz S, Zhang S, Sohns JM, Lotz J, Frahm J. Real-time flow MRI of the aorta at a resolution of 40 msec. J Magn Reson Imaging 2013; 40:206-13. [PMID: 24123295 DOI: 10.1002/jmri.24328] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 07/10/2013] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To evaluate a novel real-time phase-contrast magnetic resonance imaging (MRI) technique for the assessment of through-plane flow in the ascending aorta. MATERIALS AND METHODS Real-time MRI was based on a radial fast low-angle shot (FLASH) sequence with about 30-fold undersampling and image reconstruction by regularized nonlinear inversion. Phase-contrast maps were obtained from two (interleaved or sequential) acquisitions with and without a bipolar velocity-encoding gradient. Blood flow in the ascending aorta was studied in 10 healthy volunteers at 3 T by both real-time MRI (15 sec during free breathing) and electrocardiogram (ECG)-synchronized cine MRI (with and without breath holding). Flow velocities and stroke volumes were evaluated using standard postprocessing software. RESULTS The total acquisition time for a pair of phase-contrast images was 40.0 msec (TR/TE = 2.86/1.93 msec, 10° flip angle, 7 spokes per image) for a nominal in-plane resolution of 1.3 mm and a section thickness of 6 mm. Quantitative evaluations of spatially averaged flow velocities and stroke volumes were comparable for real-time and cine methods when real-time MRI data were averaged across heartbeats. For individual heartbeats real-time phase-contrast MRI resulted in higher peak velocities for values above 120 cm s(-1). CONCLUSION Real-time phase-contrast MRI of blood flow in the human aorta yields functional parameters for individual heartbeats. When averaged across heartbeats real-time flow velocities and stroke volumes are comparable to values obtained by conventional cine MRI.
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Affiliation(s)
- Arun Joseph
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
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31
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Lorenz R, Bock J, Barker AJ, von Knobelsdorff-Brenkenhoff F, Wallis W, Korvink JG, Bissell MM, Schulz-Menger J, Markl M. 4D flow magnetic resonance imaging in bicuspid aortic valve disease demonstrates altered distribution of aortic blood flow helicity. Magn Reson Med 2013; 71:1542-53. [PMID: 23716466 DOI: 10.1002/mrm.24802] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 03/27/2013] [Accepted: 04/17/2013] [Indexed: 11/06/2022]
Abstract
PURPOSE Changes in aortic geometry or presence of aortic valve (AoV) disease can result in substantially altered aortic hemodynamics. Dilatation of the ascending aorta or AoV abnormalities can result in an increase in helical flow. METHODS 4D flow magnetic resonance imaging was used to test the feasibility of quantitative helicity analysis using equidistantly distributed 2D planes along the entire aorta. The evaluation of the method included three parts: (1) the quantification of helicity in 12 healthy subjects, (2) an evaluation of observer variability and test-retest reliability, and (3) the quantification of helical flow in 16 patients with congenitally altered bicuspid AoVs. RESULTS Helicity quantification in healthy subjects revealed consistent directions of flow rotation along the entire aorta with high clockwise helicity in the aortic arch and an opposite rotation sense in the ascending and descending aorta. The results demonstrated good scan-rescan and inter- and intraobserver agreement of the helicity parameters. Helicity quantification in patients revealed a significant increase in absolute peak relative helicity during systole and a considerably greater heterogeneous distribution of mean helicity in the aorta. CONCLUSION The method has the potential to serve as a reference distribution for comparisons of helical flow between healthy subjects and patients or between different patient groups.
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Affiliation(s)
- R Lorenz
- Department of Radiology, Medical Physics, University Medical Center Freiburg, Germany
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32
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In vivo and in vitro validation of aortic flow quantification by time-resolved three-dimensional velocity-encoded MRI. Int J Cardiovasc Imaging 2012; 28:1999-2008. [DOI: 10.1007/s10554-012-0027-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 02/01/2012] [Indexed: 10/28/2022]
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Kawaguchi T, Nishimura S, Kanamori M, Takazawa H, Omodaka S, Sato K, Maeda N, Yokoyama Y, Midorikawa H, Sasaki T, Nishijima M. Distinctive flow pattern of wall shear stress and oscillatory shear index: similarity and dissimilarity in ruptured and unruptured cerebral aneurysm blebs. J Neurosurg 2012; 117:774-80. [DOI: 10.3171/2012.7.jns111991] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
The difference in the hemodynamics of wall shear stress (WSS) and oscillatory shear index (OSI) between ruptured and unruptured aneurysms is not well understood. The authors investigated the hemodynamic similarities and dissimilarities in ruptured and thin-walled unruptured aneurysm blebs.
Methods
Magnetic resonance imaging–based fluid dynamics analysis was used to calculate WSS and OSI, and hemodynamic and intraoperative findings were compared. The authors also compared ruptured and unruptured thin-walled blebs for the magnitude of WSS and OSI.
Results
Intraoperatively, 13 ruptured and 139 thin-walled unruptured aneurysm blebs were identified. Twelve of the ruptured (92.3%) and 124 of the unruptured blebs (89.2%) manifested low WSS and high OSI. The degree of WSS was significantly lower in ruptured (0.49 ± 0.12 Pa) than in unruptured (0.64 ± 0.15 Pa; p < 0.01) blebs.
Conclusions
Ruptured and unruptured blebs shared a distinctive pattern of low WSS and high OSI. The degree of WSS at the rupture site was significantly lower than in the unruptured thin-walled blebs.
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Affiliation(s)
| | | | | | | | | | - Kenya Sato
- 2Radiology, Aomori Prefectural Central Hospital, Aomori, Japan
| | - Noriko Maeda
- 2Radiology, Aomori Prefectural Central Hospital, Aomori, Japan
| | - Yoko Yokoyama
- 2Radiology, Aomori Prefectural Central Hospital, Aomori, Japan
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Wu Q, Li MH. A comparison of 4D time-resolved MRA with keyhole and 3D time-of-flight MRA at 3.0 T for the evaluation of cerebral aneurysms. BMC Neurol 2012; 12:50. [PMID: 22784396 PMCID: PMC3492185 DOI: 10.1186/1471-2377-12-50] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Accepted: 06/15/2012] [Indexed: 01/13/2023] Open
Abstract
Background A subarachnoid hemorrhage (SAH) due to the rupture of a cerebral aneurysm (CA) is a devastating event associated with high rates of mortality. Magnetic resonance angiography (MRA), as a noninvasive technique, is typically used initially. The object of our study is to evaluate the feasibility of 4D time-resolved MRA with keyhole (4D-TRAK) for the diagnostic accuracy and reliability of the detection and characterization of cerebral aneurysms (CAs), with a comparison of 3D time-of-flight MRA (3D-TOF-MRA) by using DSA as a reference. Methods 3D-TOF-MRA, 4D-TRAK and 3D-DSA were performed sequentially in 52 patients with suspected CAs. 4D-TRAK was acquired using a combination of sensitivity encoding (SENSE) and CE timing robust angiography (CENTRA) k-space sampling techniques at a contrast dose of 10 ml at 3 T. Accuracy, sensitivity, specificity of 4D-TRAK and 3D-TOF-MRA were calculated and compared for the detection of CAs on patient-based and aneurysm-based evaluation using 3D-DSA as a reference. Results The overall image quality of 4D-TRAK with a contrast dose of 10 ml was in the diagnostic range but still cannot be compared with that of 3D-TOF-MRA. In 52 patients with suspected CAs, fifty-eight CAs were confirmed on 3D-DSA finally. Fifty-one (with 2 false-positives and 9 false-negatives) and 58 (with 1 false-positive and 1 false-negative) CAs were visualized on 4D-TRAK and 3D-TOF-MRA, respectively. Accuracy, sensitivity and specificity on patient-based evaluation of 4D-TRAK and 3D-TOF-MRA were 92.31%, 93.33%, 85.71% and 98.08%, 100%, 85.71%, respectively, and 74.07%, 75.00%, 66.67% and 96.30%, 95.83%, 100% on aneurysm-based evaluation in patients with multiple CAs, respectively. Subgroup analysis revealed that for 19 very small CAs (maximal diameter <3 mm, measured on 3D-DSA), 9 were missed on 4D-TRAK and 1 on 3D-TOF-MRA (P = 0.008). However, for 39 CAs with maximal diameter ≥ 3 mm, the diagnostic accuracy is equally (39 on 4D-TRAK vs. 39 on 3D-TOF-MRA) (P = 1). In four larger CAs with maximal diameter ≥ 10 mm, 4D-TRAK provided a better characterization of morphology than 3D-TOF-MRA. Conclusion 4D-TRAK at a lower contrast dose of 10 ml with a combination of SENSE and CENTRA at 3 T could provide similar diagnostic accuracy rate for CAs with maximal diameter ≥ 3 mm, and a better characterization of morphology for larger CAs with maximal diameter ≥ 10 mm compared to 3D-TOF-MRA. However, further study is still needed to improve the “vascular edge” artifact and the compromise in spatial resolution in depiction of CAs with maximal diameter<3 mm.
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Affiliation(s)
- Qian Wu
- Dept of Radiology, The Sixth Affiliated People's Hospital; Medical school of Shanghai Jiaotong University, No, 600# Yishan Road, Shanghai, 200233, China
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Strecker C, Harloff A, Wallis W, Markl M. Flow-sensitive 4D MRI of the thoracic aorta: Comparison of image quality, quantitative flow, and wall parameters at 1.5 T and 3 T. J Magn Reson Imaging 2012; 36:1097-103. [DOI: 10.1002/jmri.23735] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 05/17/2012] [Indexed: 11/09/2022] Open
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James SH, Wald R, Wintersperger BJ, Jimenez-Juan L, Deva D, Crean AM, Nguyen E, Paul NS, Ley S. Accuracy of right and left ventricular functional assessment by short-axis vs axial cine steady-state free-precession magnetic resonance imaging: intrapatient correlation with main pulmonary artery and ascending aorta phase-contrast flow measurements. Can Assoc Radiol J 2012; 64:213-9. [PMID: 22579337 DOI: 10.1016/j.carj.2011.12.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 11/11/2011] [Accepted: 12/19/2011] [Indexed: 11/30/2022] Open
Abstract
OBJECTIVE The left ventricle (LV) is routinely assessed with cardiac magnetic resonance imaging (MRI) by using short-axis orientation; it remains unclear whether the right ventricle (RV) can also be adequately assessed in this orientation or whether dedicated axial orientation is required. We used phase-contrast (PC) flow measurements in the main pulmonary artery (MPA) and the ascending aorta (Aorta) as nonvolumetric standard of reference and compared RV and LV volumes in short-axis and axial orientations. METHODS A retrospective analysis identified 30 patients with cardiac MRI data sets. Patients underwent MRI (1.5 T or 3 T), with retrospectively gated cine steady-state free-precession in axial and short-axis orientations. PC flow analyses of MPA and Aorta were used as the reference measure of RV and LV output. RESULTS There was a high linear correlation between MPA-PC flow and RV-stroke volume (SV) short axis (r = 0.9) and RV-SV axial (r = 0.9). Bland-Altman analysis revealed a mean offset of 1.4 mL for RV axial and -2.3 mL for RV-short-axis vs MPA-PC flow. There was a high linear correlation between Aorta-PC flow and LV-SV short-axis (r = 0.9) and LV-SV axial (r = 0.9). Bland-Altman analysis revealed a mean offset of 4.8 m for LV short axis and 7.0 mL for LV axial vs Aorta-PC flow. There was no significant difference (P = .6) between short-axis-LV SV and short-axis-RV SV. CONCLUSION No significant impact of the slice acquisition orientation for determination of RV and LV stroke volumes was found. Therefore, cardiac magnetic resonance workflow does not need to be extended by an axial data set for patients without complex cardiac disease for assessment of biventricular function and volumes.
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Affiliation(s)
- Susan H James
- Joint Department of Medical Imaging, Toronto General Hospital, University of Toronto, Ontario, Canada
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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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Hartung MP, Grist TM, François CJ. Magnetic resonance angiography: current status and future directions. J Cardiovasc Magn Reson 2011; 13:19. [PMID: 21388544 PMCID: PMC3060856 DOI: 10.1186/1532-429x-13-19] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Accepted: 03/09/2011] [Indexed: 01/06/2023] Open
Abstract
With recent improvement in hardware and software techniques, magnetic resonance angiography (MRA) has undergone significant changes in technique and approach. The advent of 3.0 T magnets has allowed reduction in exogenous contrast dose without compromising overall image quality. The use of novel intravascular contrast agents substantially increases the image windows and decreases contrast dose. Additionally, the lower risk and cost in non-contrast enhanced (NCE) MRA has sparked renewed interest in these methods. This article discusses the current state of both contrast-enhanced (CE) and NCE-MRA. New CE-MRA methods take advantage of dose reduction at 3.0 T, novel contrast agents, and parallel imaging methods. The risks of gadolinium-based contrast media, and the NCE-MRA methods of time-of-flight, steady-state free precession, and phase contrast are discussed.
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Affiliation(s)
- Michael P Hartung
- Department of Radiology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI
| | - Thomas M Grist
- Department of Radiology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI
| | - Christopher J François
- Department of Radiology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI
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Markl M, Kilner PJ, Ebbers T. Comprehensive 4D velocity mapping of the heart and great vessels by cardiovascular magnetic resonance. J Cardiovasc Magn Reson 2011; 13:7. [PMID: 21235751 PMCID: PMC3025879 DOI: 10.1186/1532-429x-13-7] [Citation(s) in RCA: 285] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2010] [Accepted: 01/14/2011] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Phase contrast cardiovascular magnetic resonance (CMR) is able to measure all three directional components of the velocities of blood flow relative to the three spatial dimensions and the time course of the heart cycle. In this article, methods used for the acquisition, visualization, and quantification of such datasets are reviewed and illustrated. METHODS Currently, the acquisition of 3D cine (4D) phase contrast velocity data, synchronized relative to both cardiac and respiratory movements takes about ten minutes or more, even when using parallel imaging and optimized pulse sequence design. The large resulting datasets need appropriate post processing for the visualization of multidirectional flow, for example as vector fields, pathlines or streamlines, or for retrospective volumetric quantification. APPLICATIONS Multidirectional velocity acquisitions have provided 3D visualization of large scale flow features of the healthy heart and great vessels, and have shown altered patterns of flow in abnormal chambers and vessels. Clinically relevant examples include retrograde streams in atheromatous descending aortas as potential thrombo-embolic pathways in patients with cryptogenic stroke and marked variations of flow visualized in common aortic pathologies. Compared to standard clinical tools, 4D velocity mapping offers the potential for retrospective quantification of flow and other hemodynamic parameters. CONCLUSIONS Multidirectional, 3D cine velocity acquisitions are contributing to the understanding of normal and pathologically altered blood flow features. Although more rapid and user-friendly strategies for acquisition and analysis may be needed before 4D velocity acquisitions come to be adopted in routine clinical CMR, their capacity to measure multidirectional flows throughout a study volume has contributed novel insights into cardiovascular fluid dynamics in health and disease.
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Affiliation(s)
- Michael Markl
- Department of Radiology, Medical Physics, University Hospital Freiburg, Germany
| | - Philip J Kilner
- CMR Unit, Royal Brompton Hospital and Imperial College, London, UK
| | - Tino Ebbers
- Center for Medical Image Science and Visualization, Linköping University, Sweden
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40
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Chang W, Landgraf B, Johnson KM, Kecskemeti S, Wu Y, Velikina J, Rowley H, Wieben O, Mistretta C, Turski P. Velocity measurements in the middle cerebral arteries of healthy volunteers using 3D radial phase-contrast HYPRFlow: comparison with transcranial Doppler sonography and 2D phase-contrast MR imaging. AJNR Am J Neuroradiol 2011; 32:54-9. [PMID: 20947642 DOI: 10.3174/ajnr.a2240] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE We have developed PC HYPRFlow, a comprehensive MRA technique that includes a whole-brain CE dynamic series followed by PC velocity-encoding, yielding a time series of high-resolution morphologic angiograms with associated velocity information. In this study, we present velocity data acquired by using the PC component of PC HYPRFlow (PC-VIPR). MATERIALS AND METHODS Ten healthy volunteers (6 women, 4 men) were scanned by using PC HYPRFlow and 2D-PC imaging, immediately followed by velocity measurements by using TCD. Velocity measurements were made in the M1 segments of the MCAs from the PC-VIPR, 2D-PC, and TCD examinations. RESULTS PC-VIPR showed approximately 30% lower mean velocity compared with TCD, consistent with other comparisons of TCD with PC-MRA. The correlation with TCD was r = 0.793, and the correlation of PC-VIPR with 2D-PC was r = 0.723. CONCLUSIONS PC-VIPR is a technique capable of acquiring high-resolution MRA of diagnostic quality with velocity data comparable with TCD and 2D-PC. The combination of velocity information and fast high-resolution whole-brain morphologic angiograms makes PC HYPRFlow an attractive alternative to current MRA methods.
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Affiliation(s)
- W Chang
- Department of Medical Physics, University of Wisconsin, Madison, Wisconsin, USA.
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Brandts A, Roes SD, Doornbos J, Weiss RG, de Roos A, Stuber M, Westenberg JJM. Right coronary artery flow velocity and volume assessment with spiral K-space sampled breathhold velocity-encoded MRI at 3 tesla: accuracy and reproducibility. J Magn Reson Imaging 2010; 31:1215-23. [PMID: 20432359 DOI: 10.1002/jmri.22144] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To evaluate accuracy and reproducibility of flow velocity and volume measurements in a phantom and in human coronary arteries using breathhold velocity-encoded (VE) MRI with spiral k-space sampling at 3 Tesla. MATERIALS AND METHODS Flow velocity assessment was performed using VE MRI with spiral k-space sampling. Accuracy of VE MRI was tested in vitro at five constant flow rates. Reproducibility was investigated in 19 healthy subjects (mean age 25.4 +/- 1.2 years, 11 men) by repeated acquisition in the right coronary artery (RCA). RESULTS MRI-measured flow rates correlated strongly with volumetric collection (Pearson correlation r = 0.99; P < 0.01). Due to limited sample resolution, VE MRI overestimated the flow rate by 47% on average when nonconstricted region-of-interest segmentation was used. Using constricted region-of-interest segmentation with lumen size equal to ground-truth luminal size, less than 13% error in flow rate was found. In vivo RCA flow velocity assessment was successful in 82% of the applied studies. High interscan, intra- and inter-observer agreement was found for almost all indices describing coronary flow velocity. Reproducibility for repeated acquisitions varied by less than 16% for peak velocity values and by less than 24% for flow volumes. CONCLUSION 3T breathhold VE MRI with spiral k-space sampling enables accurate and reproducible assessment of RCA flow velocity.
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Affiliation(s)
- Anne Brandts
- Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands.
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42
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Kumar A, Patton DJ, Friedrich MG. The emerging clinical role of cardiovascular magnetic resonance imaging. Can J Cardiol 2010; 26:313-22. [PMID: 20548977 DOI: 10.1016/s0828-282x(10)70396-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Starting as a research method little more than a decade ago, cardiovascular magnetic resonance (CMR) imaging has rapidly evolved to become a powerful diagnostic tool used in routine clinical cardiology. The contrast in CMR images is generated from protons in different chemical environments and, therefore, enables high-resolution imaging and specific tissue characterization in vivo, without the use of potentially harmful ionizing radiation.CMR imaging is used for the assessment of regional and global ventricular function, and to answer questions regarding anatomy. State-of-the-art CMR sequences allow for a wide range of tissue characterization approaches, including the identification and quantification of nonviable, edematous, inflamed, infiltrated or hypoperfused myocardium. These tissue changes are not only used to help identify the etiology of cardiomyopathies, but also allow for a better understanding of tissue pathology in vivo. CMR tissue characterization may also be used to stage a disease process; for example, elevated T2 signal is consistent with edema and helps differentiate acute from chronic myocardial injury, and the extent of myocardial fibrosis as imaged by contrast-enhanced CMR correlates with adverse patient outcome in ischemic and nonischemic cardiomyopathies.The current role of CMR imaging in clinical cardiology is reviewed, including coronary artery disease, congenital heart disease, nonischemic cardiomyopathies and valvular disease.
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Affiliation(s)
- Andreas Kumar
- Stephenson CMR Centre at the Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
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43
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Voges I, Jerosch-Herold M, Helle M, Hart C, Kramer HH, Rickers C. 3-Tesla-Magnetresonanztomographie zur Untersuchung von Kindern und Erwachsenen mit angeborenen Herzfehlern. Radiologe 2010; 50:799-806, 808. [DOI: 10.1007/s00117-010-2025-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Kang CK, Kim SH, Lee H, Park CA, Kim YB, Cho ZH. Functional MR angiography using phase contrast imaging technique at 3T MRI. Neuroimage 2010; 50:1036-43. [DOI: 10.1016/j.neuroimage.2010.01.038] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2009] [Revised: 12/14/2009] [Accepted: 01/10/2010] [Indexed: 10/20/2022] Open
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Bock J, Frydrychowicz A, Stalder AF, Bley TA, Burkhardt H, Hennig J, Markl M. 4D phase contrast MRI at 3 T: Effect of standard and blood-pool contrast agents on SNR, PC-MRA, and blood flow visualization. Magn Reson Med 2010; 63:330-8. [DOI: 10.1002/mrm.22199] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Totman JJ, Marciani L, Foley S, Campbell E, Hoad CL, Macdonald IA, Spiller RC, Gowland PA. Characterization of the time course of the superior mesenteric, abdominal aorta, internal carotid and vertebral arteries blood flow response to the oral glucose challenge test using magnetic resonance imaging. Physiol Meas 2009; 30:1117-36. [PMID: 19759401 DOI: 10.1088/0967-3334/30/10/011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Blood flow to the splanchnic circulation increases postprandially which may cause a reduction in systemic and cerebral perfusion leading to postprandial syncope in the elderly who lack adequate cardiovascular reserve. We used multi-station 2D phase contrast cine magnetic resonance imaging (PC-MRI) with the aim of characterizing the time course of the haemodynamic response to an oral glucose challenge test (OGCT) in the large arteries perfusing the splanchnic, systemic and cerebral circulations (superior mesenteric artery SMA, abdominal aorta AA, internal carotid arteries, ICA and vertebral arteries VA). In this study nine fasted healthy volunteers were studied. Separate cine PC-MRI scans were acquired in the neck and in the abdomen every 88 s, these two measurements being interleaved for ten baseline scans at each station with the scanner automatically moving the subject between the two stations. After ingestion of the OGCT, a further 30 cine PC-MRI scans were acquired at each station. Using this technique we were able to characterize with frequent sampling of volumetric blood flow the time course of blood flow response to the OGCT of the SMA, AA and both VA and ICA. We found a substantial variation between individuals in the amplitude and the time to the peak of the SMA blood flow response to the OGCT which correlated positively with body mass index. MRI provides a robust, non-invasive method of studying normal physiology that could be valuable in studies of diseases such as postprandial hypotension.
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Affiliation(s)
- J J Totman
- Brain and Body Centre, University of Nottingham, Nottingham NG7 2RD, UK
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Huang BY, Castillo M. Neurovascular imaging at 1.5 tesla versus 3.0 tesla. Magn Reson Imaging Clin N Am 2009; 17:29-46. [PMID: 19364598 DOI: 10.1016/j.mric.2008.12.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The primary advantage of high field strength MR imaging over imaging on modern 1.5 Tesla (T) systems is increased signal-to-noise ratio, which can be used to improve image quality or shorten scan acquisition time. In the years since 3.0T scanners were first approved for clinical use, one of the areas which has benefited greatly from its introduction is neurovascular MR angiography (MRA). Early experience has shown significant improvements in resolution and image quality. Whether high field strength MRA is robust or accurate enough to replace digital subtraction angiography in the foreseeable future remains to be seen. This article discusses the current state of neurovascular MRA at 3.0T, basic physical differences between MR imaging at 1.5T and 3.0T, and their effects on MRA sequences. The literature regarding the efficacy of 3.0T MRA techniques for diagnosing specific neurovascular pathologies and carotid steno occlusive disease is reviewed.
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Affiliation(s)
- Benjamin Y Huang
- Department of Radiology, University of North Carolina School of Medicine, CB#7510, 101 Manning Drive, Chapel Hill, NC 27599, USA.
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Bloch KM, Carlsson M, Arheden H, Ståhlberg F. Quantifying coronary sinus flow and global LV perfusion at 3T. BMC Med Imaging 2009; 9:9. [PMID: 19519892 PMCID: PMC2702273 DOI: 10.1186/1471-2342-9-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2008] [Accepted: 06/11/2009] [Indexed: 11/30/2022] Open
Abstract
Background Despite the large availability of 3T MR scanners and the potential of high field imaging, this technical platform has yet to prove its usefulness in the cardiac MR setting, where 1.5T remains the established standard. Global perfusion of the left ventricle, as well as the coronary flow reserve (CFR), can provide relevant diagnostic information, and MR measurements of these parameters may benefit from increased field strength. Quantitative flow measurements in the coronary sinus (CS) provide one method to investigate these parameters. However, the ability of newly developed faster MR sequences to measure coronary flow during a breath-hold at 3T has not been evaluated. Methods The aim of this work was to measure CS flow using segmented phase contrast MR (PC MR) on a clinical 3T MR scanner. Parallel imaging was employed to reduce the total acquisition time. Global LV perfusion was calculated by dividing CS flow with left ventricular (LV) mass. The repeatability of the method was investigated by measuring the flow three times in each of the twelve volunteers. Phantom experiments were performed to investigate potential error sources. Results The average CS flow was determined to 88 ± 33 ml/min and the deduced LV perfusion was 0.60 ± 0.22 ml/min·g, in agreement with published values. The repeatability (1-error) of the three repeated measurements in each subject was on average 84%. Conclusion This work demonstrates that the combination of high field strength (3T), parallel imaging and segmented gradient echo sequences allow for quantification of the CS flow and global perfusion within a breath-hold.
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Boussel L, Rayz V, Martin A, Acevedo-Bolton G, Lawton MT, Higashida R, Smith WS, Young WL, Saloner D. Phase-contrast magnetic resonance imaging measurements in intracranial aneurysms in vivo of flow patterns, velocity fields, and wall shear stress: comparison with computational fluid dynamics. Magn Reson Med 2009; 61:409-17. [PMID: 19161132 DOI: 10.1002/mrm.21861] [Citation(s) in RCA: 142] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Evolution of intracranial aneurysms is known to be related to hemodynamic forces such as wall shear stress (WSS) and maximum shear stress (MSS). Estimation of these parameters can be performed using numerical simulations with computational fluid dynamics (CFD), but can also be directly measured with magnetic resonance imaging (MRI) using a time-dependent 3D phase-contrast sequence with encoding of each of the three components of the velocity vectors (7D-MRV). To study the accuracy of 7D-MRV in estimating these parameters in vivo, in comparison with CFD, 7D-MRV and patient-specific CFD modeling was performed for 3 patients who had intracranial aneurysms. Visual and quantitative analyses of the flow pattern and distribution of velocities, MSS, and WSS were performed using the two techniques. Spearman's coefficients of correlation between the two techniques were 0.56 for the velocity field, 0.48 for MSS, and 0.59 for WSS. Visual analysis and Bland-Altman plots showed good agreement for flow pattern and velocities but large discrepancies for MSS and WSS. These results indicate that 7D-MRV can be used in vivo to measure velocity flow fields and for estimating MSS and WSS. Currently, however, this method cannot accurately quantify the latter two parameters.
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Affiliation(s)
- Loic Boussel
- Radiology Service, VA Medical Center, San Francisco, California 94121, USA.
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Harloff A, Albrecht F, Spreer J, Stalder AF, Bock J, Frydrychowicz A, Schöllhorn J, Hetzel A, Schumacher M, Hennig J, Markl M. 3D blood flow characteristics in the carotid artery bifurcation assessed by flow-sensitive 4D MRI at 3T. Magn Reson Med 2009; 61:65-74. [PMID: 19097219 DOI: 10.1002/mrm.21774] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
To determine three-dimensional (3D) blood flow patterns in the carotid bifurcation, 10 healthy volunteers and nine patients with internal carotid artery (ICA) stenosis > or =50% were examined by flow-sensitive 4D MRI at 3T. Absolute and mean blood velocities, pulsatility index (PI), and resistance index (RI) were measured in the common carotid arteries (CCAs) by duplex sonography (DS) and compared with flow-sensitive 4D MRI. Furthermore, 3D MRI blood flow patterns in the carotid bifurcation of volunteers and patients before and after recanalization were graded by two independent readers. Blood flow velocities measured by MRI were 31-39% lower than in DS. However, PI and RI differed by only 13-16%. Rating of 3D flow characteristics in the ICA revealed consistent patterns for filling and helical flow in volunteers. In patients with ICA stenosis, 3D blood flow visualization was successfully employed to detect markedly altered filling and helical flow patterns (forward-moving spiral flow) in the ICA bulb and to evaluate the effect of revascularization, which restored filling and helical flow. Our results demonstrate the feasibility of flow-sensitive 4D MRI for the quantification and 3D visualization of physiological and pathological flow patterns in the carotid artery bifurcation.
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Affiliation(s)
- A Harloff
- Department of Neurology and Clinical Neurophysiology, University of Freiburg, Freiburg, Germany.
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