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Huang Q, Mendes J, Adluru G, DiBella E. Technical note: Accuracy and precision of T2 and T2* with a gradient-echo spin-echo (GESE) sequence for cardiac imaging. Med Phys 2023; 50:7946-7954. [PMID: 37357805 DOI: 10.1002/mp.16569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 05/11/2023] [Accepted: 06/03/2023] [Indexed: 06/27/2023] Open
Abstract
BACKGROUND The use of a gradient echo spin echo (GESE) method to obtain rapid T2 and T2* estimation in the heart has been proposed. The effect of acquisition parameter settings on T2 and T2* bias and precision have not been investigated in depth. PURPOSE To understand factors impacting the quantification of T2 and T2* values with a gradient echo spin echo (GESE) method using echo planar imaging (EPI) readouts in a reduced field of view acquisition. METHODS The GESE method is implemented with a reduced field-of-view using an outer volume suppression (OVS) technique to minimize the time for multi-echo EPI readouts. The number of EPI readouts (images) for the GESE is optimized using Cramer-Rao Lower Bound (CRLB) and Monte Carlo simulations with a nonlinear least-square (NLLS) estimator. The SNR requirements were studied using the latter simulation method for a selected range of T2 and T2* values and T2/T2* ratios. Two healthy control subjects were imaged with the proposed GESE sequence and evaluated with the NLLS estimation method. In addition, the proposed OVS method was compared with a saturation bands OVS method in one subject. Clinical T2 and T2* mappings were used as the reference. RESULTS The optimal number of EPI readouts is five and the performance is slightly better when the refocusing pulse is placed between the 2nd and 3rd readouts. The SNR requirement for achieving a target bias < 1 ms and standard deviation (SD) < 5 ms is more demanding when T2/T2* ratio increases. The minimum SNR requirement in the GESE acquisition should vary from 6 to 20 depending on specific myocardial T2 and T2* values at 3T. The T2 and T2* estimates using the proposed OVS method and the saturation bands OVS method are both similar to the reference. CONCLUSION The GESE sequence with five EPI readouts is a feasible and efficient technique that can estimate T2 and T2* values in the septal myocardium within a heartbeat when the SNR requirement can be satisfied.
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Affiliation(s)
- Qi Huang
- Utah Center for Advanced Imaging Research (UCAIR), Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah, USA
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah, USA
| | - Jason Mendes
- Utah Center for Advanced Imaging Research (UCAIR), Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah, USA
| | - Ganesh Adluru
- Utah Center for Advanced Imaging Research (UCAIR), Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah, USA
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah, USA
| | - Edward DiBella
- Utah Center for Advanced Imaging Research (UCAIR), Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah, USA
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah, USA
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Johnson CP, Thedens DR, Kruger SJ, Magnotta VA. Three-Dimensional GRE T 1ρ mapping of the brain using tailored variable flip-angle scheduling. Magn Reson Med 2020; 84:1235-1249. [PMID: 32052489 DOI: 10.1002/mrm.28198] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 01/07/2020] [Accepted: 01/13/2020] [Indexed: 12/26/2022]
Abstract
PURPOSE To introduce a new approach called tailored variable flip-angle (VFA) scheduling for SNR-efficient 3D T1ρ mapping of the brain using a magnetization-prepared gradient-echo sequence. METHODS Simulations were used to assess the relative SNR efficiency, quantitative accuracy, and spatial blurring of tailored VFA scheduling for T1ρ mapping of brain tissue compared with magnetization-prepared angle-modulated partitioned k-space spoiled gradient-echo snapshots (MAPSS), a state-of-the-art technique for accurate 3D gradient-echo T1ρ mapping. Simulations were also used to calculate optimal imaging parameters for tailored VFA scheduling versus MAPSS, without and with nulling of CSF. Four participants were imaged at 3T MRI to demonstrate the feasibility of tailored VFA scheduling for T1ρ mapping of the brain. Using MAPSS as a reference standard, in vivo data were used to validate the relative SNR efficiency and quantitative accuracy of the new approach. RESULTS Tailored VFA scheduling can provide a 2-fold to 4-fold gain in the SNR of the resulting T1ρ map as compared with MAPSS when using identical sequence parameters while limiting T1ρ quantification errors to 2% or less. In vivo whole-brain 3D T1ρ maps acquired with tailored VFA scheduling had superior SNR efficiency than is achievable with MAPSS, and the SNR efficiency improved with a greater number of views per segment. CONCLUSIONS Tailored VFA scheduling is an SNR-efficient GRE technique for 3D T1ρ mapping of the brain that provides increased flexibility in choice of imaging parameters compared with MAPSS, which may benefit a variety of applications.
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Affiliation(s)
- Casey P Johnson
- Veterinary Clinical Sciences Department, University of Minnesota, Saint Paul, MN, USA.,Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
| | | | | | - Vincent A Magnotta
- Department of Radiology, University of Iowa, Iowa City, IA, USA.,Department of Psychiatry, University of Iowa, Iowa City, IA, USA.,Department of Biomedical Engineering, University of Iowa, Iowa City, IA, USA
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3
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Morita K, Oda S, Utsunomiya D, Nakaura T, Matsubara T, Goto M, Okuaki T, Yuki H, Nagayama Y, Kidoh M, Hirata K, Iyama Y, Taguchi N, Hatemura M, Hashida M, Yamashita Y. Saturation Recovery Myocardial T 1 Mapping with a Composite Radiofrequency Pulse on a 3T MR Imaging System. Magn Reson Med Sci 2017; 17:35-41. [PMID: 28515409 PMCID: PMC5760231 DOI: 10.2463/mrms.mp.2016-0092] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To evaluate the effect of a composite radiofrequency (RF) pulse on saturation recovery (SR) myocardial T1 mapping using a 3T MR system. MATERIALS AND METHODS Phantom and in vivo studies were performed with a clinical 3T MR scanner. Accuracy and reproducibility of the SR T1 mapping using conventional and composite RF pulses were first compared in phantom experiments. An in vivo study was performed of 10 healthy volunteers who were imaged with conventional and composite RF pulse methods twice each. In vivo reproducibility of myocardial T1 value and the inter-segment variability were assessed. RESULTS The phantom study revealed significant differences in the mean T1 values between the two methods, and the reproducibility for the composite RF pulse was significantly smaller than that for the conventional RF pulse. For both methods, the correlations of the reference and measured T1 values were excellent (r2 = 0.97 and 0.98 for conventional and composite RF pulses, respectively). The in vivo study showed that the mean T1 value for composite RF pulse was slightly lower than that for conventional RF pulse, but this difference was not significant (P = 0.06). The inter-segment variability for the composite RF pulse was significantly smaller than that for conventional RF pulse (P < 0.01). Inter-scan correlations of T1 measurements of the first and second scans were highly and weakly correlated to composite RF pulses (r = 0.83 and 0.29, respectively). CONCLUSION SR T1 mapping using composite RF pulse provides accurate quantification of T1 values and can lessen measurement variability and enable reproducible T1 measurements.
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Affiliation(s)
- Kosuke Morita
- Department of Central Radiology, Kumamoto University Hospital
| | - Seitaro Oda
- Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University
| | - Daisuke Utsunomiya
- Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University
| | - Takeshi Nakaura
- Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University
| | | | - Makoto Goto
- Department of Central Radiology, Kumamoto University Hospital
| | | | - Hideaki Yuki
- Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University
| | - Yasunori Nagayama
- Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University
| | - Masafumi Kidoh
- Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University
| | - Kenichiro Hirata
- Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University
| | - Yuij Iyama
- Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University
| | - Narumi Taguchi
- Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University
| | | | | | - Yasuyuki Yamashita
- Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University
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4
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Tran-Gia J, Lohr D, Weng AM, Ritter CO, Stäb D, Bley TA, Köstler H. A model-based reconstruction technique for quantitative myocardial perfusion imaging. Magn Reson Med 2015; 76:880-7. [PMID: 26414857 DOI: 10.1002/mrm.25921] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 07/19/2015] [Accepted: 08/14/2015] [Indexed: 12/20/2022]
Abstract
PURPOSE To reduce saturation effects in the arterial input function (AIF) estimation of quantitative myocardial first-pass saturation recovery perfusion imaging by employing a model-based reconstruction. THEORY AND METHODS Imaging was performed with a saturation recovery prepared radial FLASH sequence. A model-based reconstruction was applied for reconstruction. By exploiting prior knowledge about the relaxation process, an image series with different saturation recovery times was reconstructed. By evaluating images with an effective saturation time of approximately 3 ms, saturation effects in the AIF determination were reduced. In a volunteer study, this approach was compared with a standard prebolus technique. RESULTS In comparison to the low-dose injection of a prebolus acquisition, saturation effects were further reduced in the AIFs determined using the model-based approach. These effects, which were clearly visible for all six volunteers, were reflected in a statistically significant difference of up to 20% in the absolute perfusion values. CONCLUSION The application of model-based reconstruction algorithms in quantitative myocardial perfusion imaging promises a significant improvement of the AIF determination. In addition to greatly reducing saturation effects that occur even for the prebolus methods, only a single bolus has to be applied. Magn Reson Med 76:880-887, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Johannes Tran-Gia
- Department of Diagnostic and Interventional Radiology, University of Würzburg, Germany.,Department of Nuclear Medicine, University of Würzburg, Germany
| | - David Lohr
- Department of Diagnostic and Interventional Radiology, University of Würzburg, Germany.,Comprehensive Heart Failure Center Würzburg, University of Würzburg, Germany
| | - Andreas Max Weng
- Department of Diagnostic and Interventional Radiology, University of Würzburg, Germany
| | - Christian Oliver Ritter
- Department of Diagnostic and Interventional Radiology, University of Würzburg, Germany.,Department of Diagnostic and Interventional Radiology, University Medical Center Göttingen, Germany
| | - Daniel Stäb
- Department of Diagnostic and Interventional Radiology, University of Würzburg, Germany.,Centre for Advanced Imaging, University of Queensland, Brisbane, Australia
| | | | - Herbert Köstler
- Department of Diagnostic and Interventional Radiology, University of Würzburg, Germany.,Comprehensive Heart Failure Center Würzburg, University of Würzburg, Germany
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5
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Hong K, Jeong EK, Wall TS, Drakos SG, Kim D. Wideband arrhythmia-Insensitive-rapid (AIR) pulse sequence for cardiac T1 mapping without image artifacts induced by an implantable-cardioverter-defibrillator. Magn Reson Med 2015; 74:336-45. [PMID: 25975192 DOI: 10.1002/mrm.25712] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 03/06/2015] [Accepted: 03/06/2015] [Indexed: 01/05/2023]
Abstract
PURPOSE To develop and evaluate a wideband arrhythmia-insensitive-rapid (AIR) pulse sequence for cardiac T1 mapping without image artifacts induced by implantable-cardioverter-defibrillator (ICD). METHODS We developed a wideband AIR pulse sequence by incorporating a saturation pulse with wide frequency bandwidth (8.9 kHz) to achieve uniform T1 weighting in the heart with ICD. We tested the performance of original and "wideband" AIR cardiac T1 mapping pulse sequences in phantom and human experiments at 1.5 Tesla. RESULTS In five phantoms representing native myocardium and blood and postcontrast blood/tissue T1 values, compared with the control T1 values measured with an inversion-recovery pulse sequence without ICD, T1 values measured with original AIR with ICD were considerably lower (absolute percent error > 29%), whereas T1 values measured with wideband AIR with ICD were similar (absolute percent error < 5%). Similarly, in 11 human subjects, compared with the control T1 values measured with original AIR without ICD, T1 measured with original AIR with ICD was significantly lower (absolute percent error > 10.1%), whereas T1 measured with wideband AIR with ICD was similar (absolute percent error < 2.0%). CONCLUSION This study demonstrates the feasibility of a wideband pulse sequence for cardiac T1 mapping without significant image artifacts induced by ICD.
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Affiliation(s)
- KyungPyo Hong
- Department of Bioengineering, University of Utah, Salt Lake City, Utah, USA.,UCAIR, Department of Radiology, University of Utah, Salt Lake City, Utah, USA
| | - Eun-Kee Jeong
- UCAIR, Department of Radiology, University of Utah, Salt Lake City, Utah, USA
| | - T Scott Wall
- Division of Cardiology, Internal Medicine, University of Utah, Salt Lake, Utah, USA
| | - Stavros G Drakos
- Division of Cardiology, Internal Medicine, University of Utah, Salt Lake, Utah, USA
| | - Daniel Kim
- UCAIR, Department of Radiology, University of Utah, Salt Lake City, Utah, USA
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6
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Broadbent DA, Biglands JD, Ripley DP, Higgins DM, Greenwood JP, Plein S, Buckley DL. Sensitivity of quantitative myocardial dynamic contrast-enhanced MRI to saturation pulse efficiency, noise and t1 measurement error: Comparison of nonlinearity correction methods. Magn Reson Med 2015; 75:1290-300. [PMID: 25946025 DOI: 10.1002/mrm.25726] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 03/19/2015] [Accepted: 03/20/2015] [Indexed: 12/12/2022]
Abstract
PURPOSE To compare methods designed to minimize or correct signal nonlinearity in quantitative myocardial dynamic contrast-enhanced (DCE) MRI. METHODS DCE-MRI studies were simulated and data acquired in eight volunteers. Signal nonlinearity was corrected using either a dual-bolus approach or model-based correction using proton-density weighted imaging (conventional or dual-sequence acquisition) or T1 data (native or bookend). Scanning of healthy and infarcted myocardium at 3 T was simulated, including noise, saturation imperfection and T1 measurement error. Data were analyzed using model-based deconvolution with a one-compartment (mono-exponential) model. RESULTS Substantial variation between methods was demonstrated in volunteers. In simulations the dual-bolus method proved stable for realistic levels of saturation efficiency but demonstrated bias due to residual nonlinearity. Model-based methods performed ideally in the absence of confounding error sources and were generally robust to noise or saturation imperfection, except for native T1 based correction which was highly sensitive to the latter. All methods demonstrated large variation in accuracy above an over-saturation level where baseline signal was nulled. For the dual-sequence approach this caused substantial bias at the saturation efficiencies observed in volunteers. CONCLUSION The choice of nonlinearity correction method in myocardial DCE-MRI impacts on accuracy and precision of estimated parameters, particularly in the presence of nonideal saturation.
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Affiliation(s)
- David A Broadbent
- Division of Biomedical Imaging, University of Leeds, Leeds, United Kingdom.,Department of Medical Physics and Engineering, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom.,Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, United Kingdom
| | - John D Biglands
- Division of Biomedical Imaging, University of Leeds, Leeds, United Kingdom.,Department of Medical Physics and Engineering, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom.,Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, United Kingdom
| | - David P Ripley
- Division of Biomedical Imaging, University of Leeds, Leeds, United Kingdom.,Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, United Kingdom
| | | | - John P Greenwood
- Division of Biomedical Imaging, University of Leeds, Leeds, United Kingdom.,Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, United Kingdom
| | - Sven Plein
- Division of Biomedical Imaging, University of Leeds, Leeds, United Kingdom.,Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, United Kingdom
| | - David L Buckley
- Division of Biomedical Imaging, University of Leeds, Leeds, United Kingdom.,Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, United Kingdom
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7
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Ding H, Fernandez-de-Manuel L, Schär M, Schuleri KH, Halperin H, He L, Zviman MM, Beinart R, Herzka DA. Three-dimensional whole-heart T2 mapping at 3T. Magn Reson Med 2014; 74:803-16. [PMID: 25242141 DOI: 10.1002/mrm.25458] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 08/23/2014] [Accepted: 08/25/2014] [Indexed: 01/28/2023]
Abstract
PURPOSE Detecting variations in myocardial water content with T2 mapping is superior to conventional T2 -weighted MRI since quantification enables direct observation of complicated pathology. Most commonly used T2 mapping techniques are limited in achievable spatial and/or temporal resolution, both of which reduce accuracy due to partial-volume averaging and misregistration between images. The goal of this study was to validate a novel free breathing T2 mapping sequence that overcomes these limitations. METHODS The proposed technique was made insensitive to heart rate variability through the use of a saturation prepulse to reset magnetization every heartbeat. Respiratory navigator-gated, differentially T2 -weighted volumes were interleaved per heartbeat, guaranteeing registered images and robust voxel-by-voxel T2 maps. Free breathing acquisitions removed limits on spatial resolution and allowed short diastolic windows. Accuracy was quantified with simulations and phantoms. RESULTS Homogeneous three-dimensional (3D) T2 maps were obtained from normal human subjects and swine. Normal human and swine left ventricular T2 values were 42.3 ± 4.0 and 43.5 ± 4.3 ms, respectively. The T2 value for edematous myocardium obtained from a swine model of acute myocardial infarction was 59.1 ± 7.1 ms. CONCLUSION Free-breathing accurate 3D T2 mapping is feasible and may be applicable in myocardial assessment in lieu of current clinical black blood, T2 -weighted techniques.
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Affiliation(s)
- Haiyan Ding
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University, Beijing, People's Republic of China.,Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Laura Fernandez-de-Manuel
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland, USA.,Biomedical Image Technologies Laboratory, ETSI Telecomunicación, Universidad Politécnica de Madrid, and CIBER-BBN, Madrid, Spain
| | - Michael Schär
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins School of Medicine, Baltimore, Maryland, USA.,Philips Healthcare, Cleveland, Ohio, USA
| | - Karl H Schuleri
- Department of Medicine, Cardiology, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Henry Halperin
- Department of Medicine, Cardiology, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Le He
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University, Beijing, People's Republic of China
| | - M Muz Zviman
- Department of Medicine, Cardiology, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Roy Beinart
- Department of Medicine, Cardiology, Johns Hopkins School of Medicine, Baltimore, Maryland, USA.,Heart Institute, Sheba Medical Center, Tel Aviv University, Ramat Gan, Israel
| | - Daniel A Herzka
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
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8
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Chen D, Sharif B, Dharmakumar R, Thomson LEJ, Bairey Merz CN, Berman DS, Li D. Quantification of myocardial blood flow using non-ECG-triggered MR imaging. Magn Reson Med 2014; 74:765-71. [PMID: 25227935 DOI: 10.1002/mrm.25451] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 08/19/2014] [Accepted: 08/22/2014] [Indexed: 12/11/2022]
Abstract
PURPOSE MR myocardial perfusion imaging is dependent on reliable electrocardiogram (ECG) triggering for accurate measurement of myocardial blood flow (MBF). A non-ECG-triggered method for quantitative first-pass imaging may improve clinical feasibility in patients with poor ECG signal. The purpose of this study is to evaluate the feasibility of a non-ECG-triggered method for myocardial perfusion imaging in a single slice. METHODS The proposed non-ECG-triggered technique uses a saturation-recovery magnetization preparation and golden-angle radial acquisition for integrated arterial input function (AIF) measurement. Image based self-gating with a temporal resolution of 42.6 ms is used to generate a first-pass image series with consistent cardiac phase. The AIF is measured using beat-by-beat T1 estimation of the ventricular blood pool. The proposed technique was performed on 14 healthy volunteers and compared against a conventional ECG-triggered dual-bolus acquisition. RESULTS The proposed method produced MBF with no significant difference compared with ECG-triggered technique (mean of 0.63 ± 0.22 mL/min/g to 0.73 ± 0.21 mL/min/g). CONCLUSION We have developed a non-ECG-triggered perfusion imaging method with T1 based measurement of the AIF in a single slice. In this preliminary study, our results demonstrate that MBF measured using the proposed method is comparable to the conventional ECG-triggered method.
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Affiliation(s)
- David Chen
- Department of Biomedical Engineering, Northwestern University, Chicago, Illinois, USA.,Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Behzad Sharif
- Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Rohan Dharmakumar
- Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA.,David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Louise E J Thomson
- S. Mark Taper Foundation Imaging Center, Department of Imaging, Cedars-Sinai Medical Center, Los Angeles, CA, USA.,Barbara Streisand Women's Heart Center, Cedars-Sinai Heart Institute, Los Angeles, California, USA
| | - C Noel Bairey Merz
- Barbara Streisand Women's Heart Center, Cedars-Sinai Heart Institute, Los Angeles, California, USA
| | - Daniel S Berman
- Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA.,S. Mark Taper Foundation Imaging Center, Department of Imaging, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Debiao Li
- Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA.,David Geffen School of Medicine, University of California, Los Angeles, California, USA
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9
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Sharif B, Dharmakumar R, LaBounty T, Arsanjani R, Shufelt C, Thomson L, Merz CNB, Berman DS, Li D. Towards elimination of the dark-rim artifact in first-pass myocardial perfusion MRI: removing Gibbs ringing effects using optimized radial imaging. Magn Reson Med 2014; 72:124-36. [PMID: 24030840 PMCID: PMC4176898 DOI: 10.1002/mrm.24913] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2013] [Revised: 07/11/2013] [Accepted: 07/15/2013] [Indexed: 11/11/2022]
Abstract
PURPOSE Subendocardial dark-rim artifacts (DRAs) remain a major concern in first-pass perfusion (FPP) myocardial MRI and may lower the diagnostic accuracy for detection of ischemia. A major source of DRAs is the "Gibbs ringing" effect. We propose an optimized radial acquisition strategy aimed at eliminating ringing-induced DRAs in FPP. THEORY AND METHODS By studying the underlying point spread function (PSF), we show that optimized radial sampling with a simple reconstruction method can eliminate the oscillations in the PSF that cause ringing artifacts. We conducted realistic MRI phantom experiments and in vivo studies (n = 12 healthy humans) to evaluate the artifact behavior of the proposed imaging scheme in comparison to a conventional Cartesian imaging protocol. RESULTS Simulations and phantom experiments verified our theoretical expectations. The in vivo studies showed that optimized radial imaging is capable of significantly reducing DRAs in the early myocardial enhancement phase (during which the ringing effect is most prominent and may obscure perfusion defects) while providing similar resolution and image quality compared with conventional Cartesian imaging. CONCLUSION The developed technical framework and results demonstrate that, in comparison to conventional Cartesian techniques, optimized radial imaging with the proposed optimizations significantly reduces the prevalence and spatial extent of DRAs in FPP imaging.
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Affiliation(s)
- Behzad Sharif
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Rohan Dharmakumar
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Troy LaBounty
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Departments of Medicine and Radiology, University of Michigan, Ann Arbor, MI, USA
| | - Reza Arsanjani
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Chrisandra Shufelt
- Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Barbra Streisand Women's Heart Center, Cedars-Sinai Heart Institute, Los Angeles, CA, USA
| | - Louise Thomson
- Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - C. Noel Bairey Merz
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Barbra Streisand Women's Heart Center, Cedars-Sinai Heart Institute, Los Angeles, CA, USA
| | - Daniel S. Berman
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Debiao Li
- Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, USA
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10
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Gill AB, Black RT, Bowden DJ, Priest AN, Graves MJ, Lomas DJ. An investigation into the effects of temporal resolution on hepatic dynamic contrast-enhanced MRI in volunteers and in patients with hepatocellular carcinoma. Phys Med Biol 2014; 59:3187-200. [PMID: 24862216 DOI: 10.1088/0031-9155/59/12/3187] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This study investigated the effect of temporal resolution on the dual-input pharmacokinetic (PK) modelling of dynamic contrast-enhanced MRI (DCE-MRI) data from normal volunteer livers and from patients with hepatocellular carcinoma. Eleven volunteers and five patients were examined at 3 T. Two sections, one optimized for the vascular input functions (VIF) and one for the tissue, were imaged within a single heart-beat (HB) using a saturation-recovery fast gradient echo sequence. The data was analysed using a dual-input single-compartment PK model. The VIFs and/or uptake curves were then temporally sub-sampled (at interval ▵t = [2-20] s) before being subject to the same PK analysis. Statistical comparisons of tumour and normal tissue PK parameter values using a 5% significance level gave rise to the same study results when temporally sub-sampling the VIFs to HB < ▵t <4 s. However, sub-sampling to ▵t > 4 s did adversely affect the statistical comparisons. Temporal sub-sampling of just the liver/tumour tissue uptake curves at ▵t ≤ 20 s, whilst using high temporal resolution VIFs, did not substantially affect PK parameter statistical comparisons. In conclusion, there is no practical advantage to be gained from acquiring very high temporal resolution hepatic DCE-MRI data. Instead the high temporal resolution could be usefully traded for increased spatial resolution or SNR.
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Affiliation(s)
- Andrew B Gill
- Department of Radiology, University of Cambridge, Cambridge, UK. Department of Medical Physics, Cambridge University Hospitals, Cambridge, UK
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11
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Zun Z, Hargreaves BA, Rosenberg J, Zaharchuk G. Improved multislice perfusion imaging with velocity-selective arterial spin labeling. J Magn Reson Imaging 2014; 41:1422-31. [PMID: 24797337 DOI: 10.1002/jmri.24652] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 04/21/2014] [Accepted: 04/23/2014] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To improve the multislice performance of velocity-selective arterial spin labeling (VS-ASL) imaging for cerebral blood flow (CBF) measurement such that it might be routinely applied for clinical applications with whole brain coverage. MATERIALS AND METHODS VS-ASL was performed with improvements such as timing optimization, stimulated echo removal, and slice profile sharpening. Each improvement was evaluated in volunteers by measuring temporal noise in the CBF measurement. VS-ASL with all these improvements was performed in 20 patients with Moyamoya disease some of whom also underwent xenon-enhanced CT (xeCT) imaging which was the reference standard for CBF measurement. RESULTS Sequence timing optimization and inter-slice crosstalk reduction using stimulated echo removal and slice profile sharpening all contributed to reduction of temporal noise. VS-ASL imaging with all these improvements performed in Moyamoya disease patients showed significant reduction of temporal noise (P < 0.0001) and increased correlation coefficient with xeCT CBF imaging (from 0.07 to 0.62). CONCLUSION We demonstrated that timing optimization, stimulated echo removal, and slice profile improvement have a large effect on image quality and robustness of VS-ASL in clinical imaging applications.
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Affiliation(s)
- Zungho Zun
- Department of Radiology, School of Medicine, Stanford University, Stanford, California, USA
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12
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Tao Y, Hess AT, Keith GA, Rodgers CT, Liu A, Francis JM, Neubauer S, Robson MD. Optimized saturation pulse train for human first-pass myocardial perfusion imaging at 7T. Magn Reson Med 2014; 73:1450-6. [PMID: 24753130 PMCID: PMC4377098 DOI: 10.1002/mrm.25262] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 04/01/2014] [Accepted: 04/01/2014] [Indexed: 12/13/2022]
Abstract
Purpose To investigate whether saturation using existing methods developed for 3T imaging is feasible for clinical perfusion imaging at 7T, and to propose a new design of saturation pulse train for first-pass myocardial perfusion imaging at 7T. Methods The new design of saturation pulse train consists of four hyperbolic-secant (HS8) radiofrequency pulses, whose peak amplitudes are optimized for a target range of static and transmit field variations and radiofrequency power deposition restrictions measured in the myocardium at 7T. The proposed method and existing methods were compared in simulation, phantom, and in vivo experiments. Results In healthy volunteer experiments without contrast agent, average saturation efficiency with the proposed method was 97.8%. This is superior to results from the three previously published methods at 86/95/90.8%. The first series of human first-pass myocardial perfusion images at 7T have been successfully acquired with the proposed method. Conclusion Existing saturation methods developed for 3T imaging are not optimal for perfusion imaging at 7T. The proposed new design of saturation pulse train can saturate effectively, and with this method first-pass myocardial perfusion imaging is feasible in humans at 7T. Magn Reson Med 73:1450–1456, 2015. © 2014 The Authors. Magnetic Resonance in Medicine Published by Wiley Periodicals, Inc. on behalf of International Society of Medicine in Resonance.
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Affiliation(s)
- Yuehui Tao
- Radcliffe Department of Medicine, University of Oxford, Oxford Centre for Clinical Magnetic Resonance Research (OCMR), John Radcliffe Hospital, Oxford, OX3 9DU, UK
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13
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Rodgers CT, Piechnik SK, DelaBarre LJ, Van de Moortele PF, Snyder CJ, Neubauer S, Robson MD, Vaughan JT. Inversion recovery at 7 T in the human myocardium: measurement of T(1), inversion efficiency and B(1) (+). Magn Reson Med 2013; 70:1038-46. [PMID: 23197329 PMCID: PMC4134266 DOI: 10.1002/mrm.24548] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 09/17/2012] [Accepted: 10/10/2012] [Indexed: 12/17/2022]
Abstract
At clinical MRI field strengths (1.5 and 3 T), quantitative maps of the longitudinal relaxation time T1 of the myocardium reveal diseased tissue without requiring contrast agents. Cardiac T1 maps can be measured by Look-Locker inversion recovery sequences such as ShMOLLI at 1.5 and 3 T. Cardiovascular MRI at a field strength of 7 T has recently become feasible, but doubts have remained as to whether magnetization inversion is possible in the heart due to subject heating and technical limitations. This work extends the repertoire of 7 T cardiovascular MRI by implementing an adiabatic inversion pulse optimized for use in the heart at 7 T. A "ShMOLLI+IE" adaptation of the ShMOLLI pulse sequence has been introduced together with new postprocessing that accounts for the possibility of incomplete magnetization inversion. These methods were validated in phantoms and then used in a study of six healthy volunteers to determine the degree of magnetization inversion and the T1 of normal myocardium at 7 T within a 22-heartbeat breathhold. Using a scanner with 16 × 1 kW radiofrequency outputs, inversion efficiencies ranging from -0.79 to -0.83 (intrasegment means; perfect 180° would give -1) were attainable across the myocardium. The myocardial T1 was 1925 ± 48 ms (mean ± standard deviation).
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Affiliation(s)
- Christopher T. Rodgers
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Level 0, John Radcliffe Hospital, Oxford, OX3 9DU, UK
| | - Stefan K. Piechnik
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Level 0, John Radcliffe Hospital, Oxford, OX3 9DU, UK
| | - Lance J. DelaBarre
- Center for Magnetic Resonance Research, University of Minnesota, 2021 Sixth Street SE, Minneapolis, MN 55455, USA
| | | | - Carl J. Snyder
- Center for Magnetic Resonance Research, University of Minnesota, 2021 Sixth Street SE, Minneapolis, MN 55455, USA
| | - Stefan Neubauer
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Level 0, John Radcliffe Hospital, Oxford, OX3 9DU, UK
| | - Matthew D. Robson
- Oxford Centre for Clinical Magnetic Resonance Research (OCMR), University of Oxford, Level 0, John Radcliffe Hospital, Oxford, OX3 9DU, UK
| | - J. Thomas Vaughan
- Center for Magnetic Resonance Research, University of Minnesota, 2021 Sixth Street SE, Minneapolis, MN 55455, USA
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Chen D, Sharif B, Dharmakumar R, Thomson LEJ, Bairey Merz CN, Berman DS, Li D. Improved quantification of myocardial blood flow using highly constrained back projection reconstruction. Magn Reson Med 2013; 72:749-55. [PMID: 24122950 DOI: 10.1002/mrm.24958] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 07/24/2013] [Accepted: 08/27/2013] [Indexed: 01/11/2023]
Abstract
PURPOSE To improve quantification of myocardial blood flow using a fast T1 mapping technique using highly constrained back projection reconstruction (HYPR)-accelerated acquisition. METHODS A major source of error in the measurement of myocardial blood flow (MBF) using MRI is the nonlinear relationship between image signal intensity and contrast agent (CA) concentration. HYPR-accelerated radial acquisition was used to generate pixel-wise T1 maps with a temporal resolution of one heartbeat. HYPR produces images with a temporal footprint of 40 ms and four images within 188 ms. T1 values were converted into CA concentrations by the known linear relationship between CA concentration and T1 . The T1 mapping technique was used to quantify MBF in 10 healthy subjects and compared with MBF found using image signal intensity as well as MBF reported in the literature. RESULTS The MBF measured using the proposed method was more consistent with that previously reported in the literature and was significantly lower (P = 0.002) than that calculated using image signal intensity (1.11 ± 0.27 mL/min/g versus 1.88 ± 0.45 mL/min/g, respectively). CONCLUSION We developed a fast T1 mapping method for MBF quantification using radial sampling and HYPR. Further validation is required to determine its clinical value in assessing myocardial perfusion deficit in coronary artery disease.
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Affiliation(s)
- David Chen
- Department of Biomedical Engineering, Northwestern University, Chicago, Illinois, USA; Biomedical Imaging Research Institute, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA
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15
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Chow K, Flewitt JA, Green JD, Pagano JJ, Friedrich MG, Thompson RB. Saturation recovery single-shot acquisition (SASHA) for myocardial T
1
mapping. Magn Reson Med 2013; 71:2082-95. [DOI: 10.1002/mrm.24878] [Citation(s) in RCA: 263] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 06/18/2013] [Accepted: 06/18/2013] [Indexed: 11/08/2022]
Affiliation(s)
- Kelvin Chow
- Department of Biomedical Engineering; Faculty of Medicine and Dentistry; University of Alberta; Edmonton Canada
| | - Jacqueline A. Flewitt
- Stephenson Cardiovascular Centre; Libin Cardiovascular Institute of Alberta, University of Calgary; Calgary Canada
- Marvin Carsley CMR Centre; Montreal Heart Institute, Université de Montréal; Montreal Canada
| | | | - Joseph J. Pagano
- Department of Biomedical Engineering; Faculty of Medicine and Dentistry; University of Alberta; Edmonton Canada
| | - Matthias G. Friedrich
- Stephenson Cardiovascular Centre; Libin Cardiovascular Institute of Alberta, University of Calgary; Calgary Canada
- Marvin Carsley CMR Centre; Montreal Heart Institute, Université de Montréal; Montreal Canada
| | - Richard B. Thompson
- Department of Biomedical Engineering; Faculty of Medicine and Dentistry; University of Alberta; Edmonton Canada
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16
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Breton E, Kim D, Chung S, Axel L. Quantitative contrast-enhanced first-pass cardiac perfusion MRI at 3 tesla with accurate arterial input function and myocardial wall enhancement. J Magn Reson Imaging 2011; 34:676-84. [PMID: 21761467 DOI: 10.1002/jmri.22647] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Accepted: 04/08/2011] [Indexed: 11/12/2022] Open
Abstract
PURPOSE To develop, and validate in vivo, a robust quantitative first-pass perfusion cardiovascular MR (CMR) method with accurate arterial input function (AIF) and myocardial wall enhancement. MATERIALS AND METHODS A saturation-recovery (SR) pulse sequence was modified to sequentially acquire multiple slices after a single nonselective saturation pulse at 3 Tesla. In each heartbeat, an AIF image is acquired in the aortic root with a short time delay (TD) (50 ms), followed by the acquisition of myocardial images with longer TD values (∼150-400 ms). Longitudinal relaxation rates (R(1) = 1/T(1)) were calculated using an ideal saturation recovery equation based on the Bloch equation, and corresponding gadolinium contrast concentrations were calculated assuming fast water exchange condition. The proposed method was validated against a reference multi-point SR method by comparing their respective R(1) measurements in the blood and left ventricular myocardium, before and at multiple time-points following contrast injections, in 7 volunteers. RESULTS R(1) measurements with the proposed method and reference multi-point method were strongly correlated (r > 0.88, P < 10(-5)) and in good agreement (mean difference ±1.96 standard deviation 0.131 ± 0.317/0.018 ± 0.140 s(-1) for blood/myocardium, respectively). CONCLUSION The proposed quantitative first-pass perfusion CMR method measured accurate R(1) values for quantification of AIF and myocardial wall contrast agent concentrations in 3 cardiac short-axis slices, in a total acquisition time of 523 ms per heartbeat.
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Affiliation(s)
- Elodie Breton
- New York University Langone Medical Center, New York, NY 10016, USA
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17
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Azlan CA, Ahearn TS, Di Giovanni P, Semple SIK, Gilbert FJ, Redpath TW. Quantification techniques to minimize the effects of native T1 variation and B1 inhomogeneity in dynamic contrast-enhanced MRI of the breast at 3 T. Magn Reson Med 2011; 67:531-40. [PMID: 21656561 DOI: 10.1002/mrm.23021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 04/22/2011] [Accepted: 05/04/2011] [Indexed: 11/06/2022]
Abstract
The variation of the native T(1) (T(10)) of different tissues and B(1) transmission-field inhomogeneity at 3 T are major contributors of errors in the quantification of breast dynamic contrast-enhanced MRI. To address these issues, we have introduced new enhancement indices derived from saturation-recovery snapshot-FLASH (SRSF) images. The stability of the new indices, i.e., the SRSF enhancement factor (EF(SRSF)) and its simplified version (EF'(SRSF)) with respect to differences in T(10) and B(1) inhomogeneity was compared against a typical index used in breast dynamic contrast-enhanced MRI, i.e., the enhancement ratio (ER), by using computer simulations. Imaging experiments with Gd-DTPA-doped gel phantoms and a female volunteer were also performed. A lower error was observed in the new indices compared to enhancement ratio in the presence of typical T(10) variation and B(1) inhomogeneity. At changes of relaxation rate (ΔR(1)) of 8 s(-1), the differences between a T(10) of 1266 and 566 ms are <1, 12, and 58%, respectively, for EF(SRSF), EF'(SRSF), and ER, whereas differences of 20, 8, and 51%, respectively, result from a 50% B(1) field reduction at the same ΔR(1). These quantification techniques may be a solution to minimize the effect of T(10) variation and B(1) inhomogeneity on dynamic contrast-enhanced MRI of the breast at 3 T.
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Affiliation(s)
- Che A Azlan
- Aberdeen Biomedical Imaging Centre, University of Aberdeen, Aberdeen, Scotland, United Kingdom.
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18
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Otazo R, Kim D, Axel L, Sodickson DK. Combination of compressed sensing and parallel imaging for highly accelerated first-pass cardiac perfusion MRI. Magn Reson Med 2011; 64:767-76. [PMID: 20535813 DOI: 10.1002/mrm.22463] [Citation(s) in RCA: 367] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
First-pass cardiac perfusion MRI is a natural candidate for compressed sensing acceleration since its representation in the combined temporal Fourier and spatial domain is sparse and the required incoherence can be effectively accomplished by k-t random undersampling. However, the required number of samples in practice (three to five times the number of sparse coefficients) limits the acceleration for compressed sensing alone. Parallel imaging may also be used to accelerate cardiac perfusion MRI, with acceleration factors ultimately limited by noise amplification. In this work, compressed sensing and parallel imaging are combined by merging the k-t SPARSE technique with sensitivity encoding (SENSE) reconstruction to substantially increase the acceleration rate for perfusion imaging. We also present a new theoretical framework for understanding the combination of k-t SPARSE with SENSE based on distributed compressed sensing theory. This framework, which identifies parallel imaging as a distributed multisensor implementation of compressed sensing, enables an estimate of feasible acceleration for the combined approach. We demonstrate feasibility of 8-fold acceleration in vivo with whole-heart coverage and high spatial and temporal resolution using standard coil arrays. The method is relatively insensitive to respiratory motion artifacts and presents similar temporal fidelity and image quality when compared to Generalized autocalibrating partially parallel acquisitions (GRAPPA) with 2-fold acceleration.
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Affiliation(s)
- Ricardo Otazo
- Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA.
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19
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Jerosch-Herold M. Quantification of myocardial perfusion by cardiovascular magnetic resonance. J Cardiovasc Magn Reson 2010; 12:57. [PMID: 20932314 PMCID: PMC2964700 DOI: 10.1186/1532-429x-12-57] [Citation(s) in RCA: 149] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Accepted: 10/08/2010] [Indexed: 11/10/2022] Open
Abstract
The potential of contrast-enhanced cardiovascular magnetic resonance (CMR) for a quantitative assessment of myocardial perfusion has been explored for more than a decade now, with encouraging results from comparisons with accepted "gold standards", such as microspheres used in the physiology laboratory. This has generated an increasing interest in the requirements and methodological approaches for the non-invasive quantification of myocardial blood flow by CMR. This review provides a synopsis of the current status of the field, and introduces the reader to the technical aspects of perfusion quantification by CMR. The field has reached a stage, where quantification of myocardial perfusion is no longer a claim exclusive to nuclear imaging techniques. CMR may in fact offer important advantages like the absence of ionizing radiation, high spatial resolution, and an unmatched versatility to combine the interrogation of the perfusion status with a comprehensive tissue characterization. Further progress will depend on successful dissemination of the techniques for perfusion quantification among the CMR community.
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20
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Oshinski JN, Delfino JG, Sharma P, Gharib AM, Pettigrew RI. Cardiovascular magnetic resonance at 3.0 T: current state of the art. J Cardiovasc Magn Reson 2010; 12:55. [PMID: 20929538 PMCID: PMC2964699 DOI: 10.1186/1532-429x-12-55] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Accepted: 10/07/2010] [Indexed: 12/12/2022] Open
Abstract
There are advantages to conducting cardiovascular magnetic resonance (CMR) studies at a field strength of 3.0 Telsa, including the increase in bulk magnetization, the increase in frequency separation of off-resonance spins, and the increase in T1 of many tissues. However, there are significant challenges to routinely performing CMR at 3.0 T, including the reduction in main magnetic field homogeneity, the increase in RF power deposition, and the increase in susceptibility-based artifacts.In this review, we outline the underlying physical effects that occur when imaging at higher fields, examine the practical results these effects have on the CMR applications, and examine methods used to compensate for these effects. Specifically, we will review cine imaging, MR coronary angiography, myocardial perfusion imaging, late gadolinium enhancement, and vascular wall imaging.
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Affiliation(s)
- John N Oshinski
- Department of Radiology, Emory University School of Medicine, 1364 Clifton Road, Room AG34, Atlanta, GA 30322, USA
- Department of Biomedical Engineering, Emory University and the Georgia Institute of Technology, 101 Woodruff Circle Woodruff Memorial Building, Suite 2001, Atlanta, Georgia 30322, USA
| | - Jana G Delfino
- Department of Radiology, Emory University School of Medicine, 1364 Clifton Road, Room AG34, Atlanta, GA 30322, USA
| | - Puneet Sharma
- Department of Radiology, Emory University School of Medicine, 1364 Clifton Road, Room AG34, Atlanta, GA 30322, USA
| | - Ahmed M Gharib
- Laboratory of Integrative Cardiovascular Imaging, Department of Radiology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Clinical Research Center, Bldg. 10, Rm. 3-5340, MSC 1263, 10 Center Dr., Bethesda, MD 20892, USA
| | - Roderic I Pettigrew
- Laboratory of Integrative Cardiovascular Imaging, Department of Radiology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Clinical Research Center, Bldg. 10, Rm. 3-5340, MSC 1263, 10 Center Dr., Bethesda, MD 20892, USA
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Kim D, Oesingmann N, McGorty K. Hybrid adiabatic-rectangular pulse train for effective saturation of magnetization within the whole heart at 3 T. Magn Reson Med 2010; 62:1368-78. [PMID: 19785021 DOI: 10.1002/mrm.22140] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Uniform T(1)-weighting is a major challenge for first-pass cardiac perfusion MRI at 3 T. Previously proposed adiabatic amplitude of radiofrequency field (B(1))-insensitive rotation (BIR-4) pulse and standard and tailored pulse trains of three nonselective pulses have been important developments but each pulse has limitations at 3 T. As an extension of the tailored pulse train, we developed a hybrid pulse train by synergistically combining two nonselective rectangular radiofrequency pulses and an adiabatic half-passage pulse, in order to achieve effective saturation of magnetization within the heart, while remaining within clinically acceptable specific absorption rate limits. The standard pulse train, tailored pulse train, hybrid pulse train, and BIR-4 pulse train were evaluated through numerical, phantom, and in vivo experiments. Among the four saturation pulses, only the hybrid pulse train yielded residual magnetization <2% of equilibrium magnetization in the heart while remaining within clinically acceptable specific absorption rate limits for multislice first-pass cardiac perfusion MRI at 3 T.
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Affiliation(s)
- Daniel Kim
- Department of Radiology, Center for Biomedical Imaging, New York University, New York, New York 10016, USA.
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22
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Christian TF, Bell SP, Whitesell L, Jerosch-Herold M. Accuracy of Cardiac Magnetic Resonance of Absolute Myocardial Blood Flow With a High-Field System. JACC Cardiovasc Imaging 2009; 2:1103-10. [DOI: 10.1016/j.jcmg.2009.06.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Revised: 05/29/2009] [Accepted: 06/03/2009] [Indexed: 10/20/2022]
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Sung K, Nayak KS. Design and use of tailored hard-pulse trains for uniformed saturation of myocardium at 3 Tesla. Magn Reson Med 2009; 60:997-1002. [PMID: 18816833 DOI: 10.1002/mrm.21765] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Complete and uniform saturation of myocardium is essential for quantitative myocardial perfusion imaging using the first pass of a contrast agent. At 3 T, inhomogeneities of both the static (B(0)) and radiofrequency (B(1)) magnetic fields have led to the use of adiabatic B(1)-insensitive rotation type 4 (BIR-4) pulses, which in practice are constrained by radiofrequency (RF) heating. In this study, we propose the use of trains of weighted hard pulses that are optimized for the measured variation of B(0) and B(1) fields in the myocardium. These pulses are simple to design, and require substantially lower RF power when compared with BIR-4 pulses. In volunteers, at 3 T, we demonstrated that the proposed saturation pulse with three subpulses results in lower peak and lower average residual longitudinal magnetization over the heart, as compared with 8-msec BIR-4 pulses and conventional hard pulse trains (P < 0.05).
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Affiliation(s)
- Kyunghyun Sung
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089-2564, USA. mail:
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McGorty K, Kim D. Effective saturation pulse for the whole heart at 3 T. J Cardiovasc Magn Reson 2009. [PMCID: PMC7851993 DOI: 10.1186/1532-429x-11-s1-p105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
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Shin T, Hu HH, Pohost GM, Nayak KS. Three dimensional first-pass myocardial perfusion imaging at 3T: feasibility study. J Cardiovasc Magn Reson 2008; 10:57. [PMID: 19077220 PMCID: PMC2614420 DOI: 10.1186/1532-429x-10-57] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2008] [Accepted: 12/11/2008] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND In patients with ischemic heart disease, accurate assessment of the extent of myocardial perfusion deficit may be important in predicting prognosis of clinical cardiac outcomes. The aim of this study was to compare the ability of three dimensional (3D) and of two dimensional (2D) multi-slice myocardial perfusion imaging (MPI) using cardiovascular magnetic resonance (CMR) in determining the size of defects, and to demonstrate the feasibility of 3D MPI in healthy volunteers at 3 Tesla. METHODS A heart phantom was used to compare the accuracy of 3D and 2D multi-slice MPI in estimating the volume fraction of seven rubber insets which simulated transmural myocardial perfusion defects. Three sets of cross-sectional planes were acquired for 2D multi-slice imaging, where each set was shifted along the partition encoding direction by +/- 10 mm. 3D first-pass contrast-enhanced (0.1 mmol/kg Gd-DTPA) MPI was performed in three volunteers with sensitivity encoding for six-fold acceleration. The upslope of the myocardial time-intensity-curve and peak SNR/CNR values were calculated. RESULTS Mean/standard deviation of errors in estimating the volume fraction across the seven defects were -0.44/1.49%, 2.23/2.97%, and 2.59/3.18% in 3D, 2D 4-slice, and 2D 3-slice imaging, respectively. 3D MPI performed in healthy volunteers produced excellent quality images with whole left ventricular (LV) coverage. Peak SNR/CNR was 57.6 +/- 22.0/37.5 +/- 19.7 over all segments in the first eight slices. CONCLUSION 3D performed better than 2D multi-slice MPI in estimating the size of perfusion defects in phantoms. Highly accelerated 3D MPI at 3T was feasible in volunteers, allowing whole LV coverage with excellent image quality and high SNR/CNR.
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Affiliation(s)
- Taehoon Shin
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California, USA
| | - Houchun H Hu
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California, USA
| | - Gerald M Pohost
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California, USA
- Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Krishna S Nayak
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California, USA
- Keck School of Medicine, University of Southern California, Los Angeles, California, USA
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Plein S, Schwitter J, Suerder D, Greenwood JP, Boesiger P, Kozerke S. k-Space and time sensitivity encoding-accelerated myocardial perfusion MR imaging at 3.0 T: comparison with 1.5 T. Radiology 2008; 249:493-500. [PMID: 18936311 DOI: 10.1148/radiol.2492080017] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PURPOSE To determine the feasibility and diagnostic accuracy of high-spatial-resolution myocardial perfusion magnetic resonance (MR) imaging at 3.0 T by using k-space and time (k-t) domain undersampling with sensitivity encoding (SENSE), or k-t SENSE. Data were compared with results of k-t SENSE-accelerated high-spatial-resolution perfusion MR imaging at 1.5 T and standard-resolution acquisition at 3.0 T. MATERIALS AND METHODS The study was reviewed and approved by the local ethics review board; informed consent was obtained. k-t SENSE perfusion MR imaging was performed at 1.5 and 3.0 T (fivefold k-t SENSE acceleration; spatial resolution, 1.3 x 1.3 x 10 mm). Fourteen volunteers were studied at rest; 37 patients were studied during adenosine-induced stress. In volunteers, comparison was also made with standard-resolution (2.5 x 2.5 x 10 mm) twofold SENSE perfusion MR imaging results at 3.0 T. Image quality, artifact scores, signal-to-noise ratios (SNRs), and contrast enhancement ratios were derived. In patients, diagnostic accuracy of visual analysis to detect stenosis of more than 50% narrowing in diameter at quantitative coronary angiography was determined by using receiver operator characteristic (ROC) analysis. RESULTS In volunteers, image quality and artifact scores were similar for 3.0- and 1.5-T k-t SENSE perfusion MR imaging, while SNR was higher (11.6 vs 5.6) and contrast enhancement ratio was lower (1.1 vs 1.5, P = .012) at 3.0 T. Compared with standard-resolution perfusion MR imaging, image quality was higher for 3.0-T k-t SENSE (3.6 vs 3.1, P = .04), endocardial dark rim artifacts were reduced (artifact thickness, 1.6 vs 2.4 mm, P < .001), and contrast enhancement ratios were similar. In patients, areas under the ROC curve for detection of coronary stenosis were 0.89 and 0.80 (P = .21) for 3.0 and 1.5 T, respectively. CONCLUSION k-t SENSE-accelerated high-spatial-resolution perfusion MR imaging at 3.0 T is feasible, with similar artifacts and diagnostic accuracy as those at 1.5 T. Compared with standard-resolution twofold SENSE perfusion MR imaging, image quality at k-t SENSE MR imaging is improved and artifacts are reduced.
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Affiliation(s)
- Sven Plein
- Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland.
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