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He T, Zur Y, Montrazi ET, Frydman L. Phase-Incremented Steady-State Free Precession as an Alternate Route to High-Resolution NMR. J Am Chem Soc 2024; 146:3615-3621. [PMID: 38291738 PMCID: PMC10870713 DOI: 10.1021/jacs.3c12954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 01/20/2024] [Accepted: 01/22/2024] [Indexed: 02/01/2024]
Abstract
Pulsed Fourier transform nuclear magnetic resonance (FT-NMR) has reigned supreme in high-resolution, high-field spectroscopy─particularly when targeting complex liquid-state samples involving multiple sharp peaks spread over large spectral bandwidths. It is known, however, that if spectral resolution is not a must, the FT-based approach is not necessarily the optimal route for maximizing NMR sensitivity: if T2 ≈ T1, as often found in solutions, Carr's steady-state free-precession (SSFP) approach can in principle provide a superior signal-to-noise ratio per √(acquisition_time) (SNRt). A rapid train of pulses will then lead to a transverse component that reaches up to 50% of the thermal equilibrium magnetization, provided that pulses are applied at repetition times TR ≪ T2, T1, and that a single suitable offset is involved. It is generally assumed that having to deal with multiple chemical shifts deprives SSFP from its advantages. The present study revisits this assumption by introducing an approach whereby arbitrarily short SSFP-derived free induction decays (FIDs) can deliver high-resolution spectra, without suffering from peak broadenings or phase distortions. To achieve discrimination among nearby frequencies, signals arising from a series of regularly phase-increased excitation pulses are collected. Given SSFP's amplitude and phase sensitivity to the spins' offset, this enables the resolution of sites according to their chemical shift position. In addition, the extreme fold-over associated with SSFP acquisitions is dealt with by a customized discrete FT of the interpulse time-domain signal. Solution-state 13C NMR spectra which compare well with FT-NMR data in terms of sensitivity, bandwidth, and resolution can then be obtained.
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Affiliation(s)
- Tian He
- Department
of Chemical and Biological Physics, Weizmann
Institute, 7610001 Rehovot, Israel
- Department
of Chemistry, Zhejiang University, Hangzhou 310058, China
| | - Yuval Zur
- Insightec
Ltd, 3903203 Tirat Carmel, Israel
| | - Elton T. Montrazi
- Department
of Chemical and Biological Physics, Weizmann
Institute, 7610001 Rehovot, Israel
| | - Lucio Frydman
- Department
of Chemical and Biological Physics, Weizmann
Institute, 7610001 Rehovot, Israel
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2
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Chen Z, Hua S, Gao J, Chen Y, Gong Y, Shen Y, Tang X, Emu Y, Jin W, Hu C. A dual-stage partially interpretable neural network for joint suppression of bSSFP banding and flow artifacts in non-phase-cycled cine imaging. J Cardiovasc Magn Reson 2023; 25:68. [PMID: 37993824 PMCID: PMC10666342 DOI: 10.1186/s12968-023-00988-z] [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: 06/25/2023] [Accepted: 11/12/2023] [Indexed: 11/24/2023] Open
Abstract
PURPOSE To develop a partially interpretable neural network for joint suppression of banding and flow artifacts in non-phase-cycled bSSFP cine imaging. METHODS A dual-stage neural network consisting of a voxel-identification (VI) sub-network and artifact-suppression (AS) sub-network is proposed. The VI sub-network provides identification of artifacts, which guides artifact suppression and improves interpretability. The AS sub-network reduces banding and flow artifacts. Short-axis cine images of 12 frequency offsets from 28 healthy subjects were used to train and test the dual-stage network. An additional 77 patients were retrospectively enrolled to evaluate its clinical generalizability. For healthy subjects, artifact suppression performance was analyzed by comparison with traditional phase cycling. The partial interpretability provided by the VI sub-network was analyzed via correlation analysis. Generalizability was evaluated for cine obtained with different sequence parameters and scanners. For patients, artifact suppression performance and partial interpretability of the network were qualitatively evaluated by 3 clinicians. Cardiac function before and after artifact suppression was assessed via left ventricular ejection fraction (LVEF). RESULTS For the healthy subjects, visual inspection and quantitative analysis found a considerable reduction of banding and flow artifacts by the proposed network. Compared with traditional phase cycling, the proposed network improved flow artifact scores (4.57 ± 0.23 vs 3.40 ± 0.38, P = 0.002) and overall image quality (4.33 ± 0.22 vs 3.60 ± 0.38, P = 0.002). The VI sub-network well identified the location of banding and flow artifacts in the original movie and significantly correlated with the change of signal intensities in these regions. Changes of imaging parameters or the scanner did not cause a significant change of overall image quality relative to the baseline dataset, suggesting a good generalizability. For the patients, qualitative analysis showed a significant improvement of banding artifacts (4.01 ± 0.50 vs 2.77 ± 0.40, P < 0.001), flow artifacts (4.22 ± 0.38 vs 2.97 ± 0.57, P < 0.001), and image quality (3.91 ± 0.45 vs 2.60 ± 0.43, P < 0.001) relative to the original cine. The artifact suppression slightly reduced the LVEF (mean bias = -1.25%, P = 0.01). CONCLUSIONS The dual-stage network simultaneously reduces banding and flow artifacts in bSSFP cine imaging with a partial interpretability, sparing the need for sequence modification. The method can be easily deployed in a clinical setting to identify artifacts and improve cine image quality.
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Affiliation(s)
- Zhuo Chen
- National Engineering Research Center of Advanced Magnetic Resonance Technologies for Diagnosis and Therapy, School of Biomedical Engineering, Shanghai Jiao Tong University, 415 S Med-X Center, 1954 Huashan Road, Shanghai, 200030, China
| | - Sha Hua
- Department of Cardiovascular Medicine, Heart Failure Center, Ruijin Hospital Lu Wan Branch, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Juan Gao
- National Engineering Research Center of Advanced Magnetic Resonance Technologies for Diagnosis and Therapy, School of Biomedical Engineering, Shanghai Jiao Tong University, 415 S Med-X Center, 1954 Huashan Road, Shanghai, 200030, China
| | - Yanjia Chen
- Department of Cardiovascular Medicine, Heart Failure Center, Ruijin Hospital Lu Wan Branch, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yiwen Gong
- Department of Cardiovascular Medicine, Heart Failure Center, Ruijin Hospital Lu Wan Branch, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yiwen Shen
- Department of Cardiovascular Medicine, Heart Failure Center, Ruijin Hospital Lu Wan Branch, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xin Tang
- National Engineering Research Center of Advanced Magnetic Resonance Technologies for Diagnosis and Therapy, School of Biomedical Engineering, Shanghai Jiao Tong University, 415 S Med-X Center, 1954 Huashan Road, Shanghai, 200030, China
| | - Yixin Emu
- National Engineering Research Center of Advanced Magnetic Resonance Technologies for Diagnosis and Therapy, School of Biomedical Engineering, Shanghai Jiao Tong University, 415 S Med-X Center, 1954 Huashan Road, Shanghai, 200030, China
| | - Wei Jin
- Department of Cardiovascular Medicine, Heart Failure Center, Ruijin Hospital Lu Wan Branch, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chenxi Hu
- National Engineering Research Center of Advanced Magnetic Resonance Technologies for Diagnosis and Therapy, School of Biomedical Engineering, Shanghai Jiao Tong University, 415 S Med-X Center, 1954 Huashan Road, Shanghai, 200030, China.
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Han PK, Marin T, Zhuo Y, Ouyang J, El Fakhri G, Ma C. Arterial spin labeled perfusion imaging with balanced steady-state free precession readout and radial sampling. Magn Reson Imaging 2023; 102:126-132. [PMID: 37187264 PMCID: PMC10524790 DOI: 10.1016/j.mri.2023.05.005] [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: 01/30/2023] [Revised: 04/19/2023] [Accepted: 05/09/2023] [Indexed: 05/17/2023]
Abstract
PURPOSE To develop an arterial spin labeling (ASL) perfusion imaging method with balanced steady-state free precession (bSSFP) readout and radial sampling for improved SNR and robustness to motion and off-resonance effects. METHODS An ASL perfusion imaging method was developed with pseudo-continuous arterial spin labeling (pCASL) and bSSFP readout. Three-dimensional (3D) k-space data were collected in segmented acquisitions following a stack-of-stars sampling trajectory. Multiple phase-cycling technique was utilized to improve the robustness to off-resonance effects. Parallel imaging with sparsity-constrained image reconstruction was used to accelerate imaging or increase the spatial coverage. RESULTS ASL with bSSFP readout showed higher spatial and temporal SNRs of the gray matter perfusion signal compared to those from spoiled gradient-recalled acquisition (SPGR). Cartesian and radial sampling schemes showed similar spatial and temporal SNRs, regardless of the imaging readout. In case of severe B0 inhomogeneity, single-RF phase incremented bSSFP acquisitions showed banding artifacts. These artifacts were significantly reduced when multiple phase-cycling technique (N = 4) was employed. The perfusion-weighted images obtained by the Cartesian sampling scheme showed respiratory motion-related artifacts when a high segmentation number was used. The perfusion-weighted images obtained by the radial sampling scheme did not show these artifacts. Whole brain perfusion imaging was feasible in 1.15 min or 4.6 min for cases without and with phase-cycling (N = 4), respectively, using the proposed method with parallel imaging. CONCLUSIONS The developed method allows non-invasive perfusion imaging of the whole-brain with relatively high SNR and robustness to motion and off-resonance effects in a practically feasible imaging time.
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Affiliation(s)
- Paul Kyu Han
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Boston, MA, United States; Department of Radiology, Harvard Medical School, Boston, MA, United States
| | - Thibault Marin
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Boston, MA, United States; Department of Radiology, Harvard Medical School, Boston, MA, United States
| | - Yue Zhuo
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Boston, MA, United States; Department of Radiology, Harvard Medical School, Boston, MA, United States
| | - Jinsong Ouyang
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Boston, MA, United States; Department of Radiology, Harvard Medical School, Boston, MA, United States
| | - Georges El Fakhri
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Boston, MA, United States; Department of Radiology, Harvard Medical School, Boston, MA, United States
| | - Chao Ma
- Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Boston, MA, United States; Department of Radiology, Harvard Medical School, Boston, MA, United States.
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Xiang J, Lamy J, Lampert R, Peters DC. Balanced Steady-State Free Precession Cine MR Imaging in the Presence of Cardiac Devices: Value of Interleaved Radial Linear Combination Acquisition With Partial Dephasing. J Magn Reson Imaging 2023; 58:782-791. [PMID: 36373998 PMCID: PMC11238270 DOI: 10.1002/jmri.28528] [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: 07/27/2022] [Revised: 10/31/2022] [Accepted: 11/01/2022] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Balanced steady-state free precession (bSSFP) is important in cardiac MRI but suffers from off-resonance artifacts. The interpretation-limiting artifacts in patients with cardiac implants remain an unsolved issue. PURPOSE To develop an interleaved radial linear combination bSSFP (lcSSFP) method with partial dephasing (PD) for improved cardiac cine imaging when implanted cardiovascular devices are present. STUDY TYPE Prospective. PHANTOM AND SUBJECTS Flow phantom adjacent to a pacemaker and 10 healthy volunteers (mean age ± standard deviation: 31.9 ± 2.9 years, 4 females) with a cardioverter-defibrillator (ICD) positioned extracorporeally at the left chest in the prepectoral region. FIELD STRENGTH/SEQUENCE A 3-T, 1) Cartesian bSSFP, 2) Cartesian gradient echo (GRE), 3) Cartesian lcSSFP, and 4) radial lcSSFP cine sequences. ASSESSMENT Flow artifacts mitigation using PD was validated with phantom experiments. Undersampled radial lcSSFP with interleaving across phase-cyclings and cardiac phases (RLC-SSFP), combined with PD, was then employed for achieving improved quality of cine images from left ventricular short-axis view. The image quality in the presence of cardiac devices was qualitatively assessed by three independent raters (1 = worst, 5 = best), regarding five criteria (banding artifacts, streak artifacts, flow artifacts, cavity visibility, and overall image quality). STATISTICAL TESTS Wilcoxon rank-sum test for the five criteria between Cartesian bSSFP cine and RLC-SSFP with PD. Fleiss kappa test for inter-reader agreement. A P value < 0.05 was considered statistically significant. RESULTS Based on simulations and phantom experiments, 60 projections per phase cycling and 1/6 PD were chosen. The in vivo experiments demonstrated significantly reduced banding artifacts (4.8 ± 0.4 vs. 2.7 ± 0.7), fewer streak artifacts (3.7 ± 0.6 vs. 2.6 ± 0.7) and flow artifacts (4.4 ± 0.4 vs. 3.7 ± 0.6), therefore improved cavity visibility (4.1 ± 0.4 vs. 2.9 ± 0.9) and overall quality (4.0 ± 0.4 vs. 2.7 ± 0.7). DATA CONCLUSION RLC-SSFP method with PD may improve cine image quality in subjects with cardiac devices. EVIDENCE LEVEL 2. TECHNICAL EFFICACY Stage 1.
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Affiliation(s)
- Jie Xiang
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut, USA
| | - Jerome Lamy
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut, USA
| | - Rachel Lampert
- Department of Medicine, Cardiovascular Division, Yale University, New Haven, Connecticut, USA
| | - Dana C. Peters
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut, USA
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut, USA
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Kim KH, Seo S, Do WJ, Luu HM, Park SH. Varying undersampling directions for accelerating multiple acquisition magnetic resonance imaging. NMR IN BIOMEDICINE 2022; 35:e4572. [PMID: 34114253 DOI: 10.1002/nbm.4572] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/27/2021] [Accepted: 05/27/2021] [Indexed: 06/12/2023]
Abstract
In this study, we propose a new sampling strategy for efficiently accelerating multiple acquisition MRI. The new sampling strategy is to obtain data along different phase-encoding directions across multiple acquisitions. The proposed sampling strategy was evaluated in multicontrast MR imaging (T1, T2, proton density) and multiple phase-cycled (PC) balanced steady-state free precession (bSSFP) imaging by using convolutional neural networks with central and random sampling patterns. In vivo MRI acquisitions as well as a public database were used to test the concept. Based on both visual inspection and quantitative analysis, the proposed sampling strategy showed better performance than sampling along the same phase-encoding direction in both multicontrast MR imaging and multiple PC-bSSFP imaging, regardless of sampling pattern (central, random) or datasets (public, retrospective and prospective in vivo). For the prospective in vivo applications, acceleration was performed by sampling along different phase-encoding directions at the time of acquisition with a conventional rectangular field of view, which demonstrated the advantage of the proposed sampling strategy in the real environment. Preliminary trials on compressed sensing (CS) also demonstrated improvement of CS with the proposed idea. Sampling along different phase-encoding directions across multiple acquisitions is advantageous for accelerating multiacquisition MRI, irrespective of sampling pattern or datasets, with further improvement through transfer learning.
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Affiliation(s)
- Ki Hwan Kim
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Sunghun Seo
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Won-Joon Do
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Huan Minh Luu
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Sung-Hong Park
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
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6
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Abstract
Osteoarthritis, characterized by the breakdown of articular cartilage and other joint structures, is one of the most prevalent and disabling chronic diseases in the United States. Magnetic resonance imaging is a commonly used imaging modality to evaluate patients with joint pain. Both two-dimensional fast spin-echo sequences (2D-FSE) and three-dimensional (3D) sequences are used in clinical practice to evaluate articular cartilage. The 3D sequences have many advantages compared with 2D-FSE sequences, such as their high in-plane spatial resolution, thin continuous slices that reduce the effects of partial volume averaging, and ability to create multiplanar reformat images following a single acquisition. This article reviews the different 3D imaging techniques available for evaluating cartilage morphology, illustrates the strengths and weaknesses of 3D approaches compared with 2D-FSE approaches for cartilage imaging, and summarizes the diagnostic performance of 2D-FSE and 3D sequences for detecting cartilage lesions within the knee and hip joints.
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Affiliation(s)
- Richard Kijowski
- Department of Radiology, New York University Grossman School of Medicine, New York, New York
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7
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Robb JS, Hu C, Peters DC. Interleaved, undersampled radial multiple-acquisition steady-state free precession for improved left atrial cine imaging. Magn Reson Med 2020; 83:1721-1729. [PMID: 31605555 PMCID: PMC6982567 DOI: 10.1002/mrm.28036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 08/31/2019] [Accepted: 09/20/2019] [Indexed: 11/10/2022]
Abstract
PURPOSE Balanced steady-state free precession (bSSFP) left atrial (LA) cine suffers from off-resonance artifacts, particularly in the pulmonary veins (PVs). Linear combination or multiple-acquisition SSFP (MA-SSFP) effectively removes banding but greatly increases scan time. We hypothesized that MA-SSFP with interleaved radial undersampling, where each phase-cycling is acquired with an interleaved set of radial projections, would improve image quality of LA cine with a small increase of scan time and streak artefacts. METHODS Undersampled radial MA-SSFP with and without interleaving was compared with fully sampled radial bSSFP by means of simulations, phantoms, and in vivo imaging. Ten healthy subjects were imaged on a 3T scanner, with bSSFP and MA-SSFP cine of the left atrium, and B0-mapping. Images were assessed (1 = worst, 5 = best) by 2 independent readers, with respect to 5 qualitative criteria and apparent signal-to-noise ratio. RESULTS In healthy subjects, off-resonance differed from the right inferior PVs to the LA cavity by 163 Hz ± 73 Hz at 3T. Compared with fully sampled radial bSSFP, interleaved radial MA-SSFP significantly improved image quality with respect to off-resonance artifacts (3.8 ± 0.6 versus 2.3 ± 1.0; P = 0.005), PV conspicuity (2.8 ± 1.0 versus 4.3 ± 0.5; P = 0.005), and the number of visualized PVs (1.7 ± 0.4 versus 0.9 ± 0.7; P = 0.008), although with greater streak artifacts (3.4 ± 0.4 versus 4.9 ± 0.2; P = 0.004) and lower measured apparent signal-to-noise ratio (24 ± 9 versus 69 ± 36; P = 0.002). Flow artifacts were similar. Interleaved radial MA-SSFP reduced streaking artifacts and increased apparent signal-to-noise ratio versus noninterleaved radial. CONCLUSIONS Interleaved radial MA-SSFP cine reduces banding artifacts with an acceptable increase of scan time and streak artifacts. The proposed technique improves the LA and PV visualization in bSSFP cine imaging.
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Affiliation(s)
| | - Chenxi Hu
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Dana C. Peters
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, Yale University, New Haven, CT, USA
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8
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Bıyık E, Keskin K, Uh Dar S, Koç A, Çukur T. Factorized sensitivity estimation for artifact suppression in phase-cycled bSSFP MRI. NMR IN BIOMEDICINE 2020; 33:e4228. [PMID: 31985879 DOI: 10.1002/nbm.4228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 10/08/2019] [Accepted: 10/25/2019] [Indexed: 06/10/2023]
Abstract
OBJECTIVE Balanced steady-state free precession (bSSFP) imaging suffers from banding artifacts in the presence of magnetic field inhomogeneity. The purpose of this study is to identify an efficient strategy to reconstruct banding-free bSSFP images from multi-coil multi-acquisition datasets. METHOD Previous techniques either assume that a naïve coil-combination is performed a priori resulting in suboptimal artifact suppression, or that artifact suppression is performed for each coil separately at the expense of significant computational burden. Here we propose a tailored method that factorizes the estimation of coil and bSSFP sensitivity profiles for improved accuracy and/or speed. RESULTS In vivo experiments show that the proposed method outperforms naïve coil-combination and coil-by-coil processing in terms of both reconstruction quality and time. CONCLUSION The proposed method enables computationally efficient artifact suppression for phase-cycled bSSFP imaging with modern coil arrays. Rapid imaging applications can efficiently benefit from the improved robustness of bSSFP imaging against field inhomogeneity.
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Affiliation(s)
- Erdem Bıyık
- Department of Electrical Engineering, Stanford University, CA, USA
- Intelligent Data Analytics Research Program Department, Aselsan Research Center, Ankara, Turkey
- Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey
| | - Kübra Keskin
- Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey
- National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey
| | - Salman Uh Dar
- Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey
- National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey
| | - Aykut Koç
- Intelligent Data Analytics Research Program Department, Aselsan Research Center, Ankara, Turkey
- Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey
- National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey
| | - Tolga Çukur
- Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey
- National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey
- Neuroscience Program at Sabuncu Brain Research Center, Bilkent University, Ankara, Turkey
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9
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Roeloffs V, Rosenzweig S, Holme HCM, Uecker M, Frahm J. Frequency-modulated SSFP with radial sampling and subspace reconstruction: A time-efficient alternative to phase-cycled bSSFP. Magn Reson Med 2018; 81:1566-1579. [PMID: 30357904 DOI: 10.1002/mrm.27505] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 07/05/2018] [Accepted: 08/03/2018] [Indexed: 11/11/2022]
Abstract
PURPOSE A novel subspace-based reconstruction method for frequency-modulated balanced steady-state free precession (fmSSFP) MRI is presented. In this work, suitable data acquisition schemes, subspace sizes, and efficiencies for banding removal are investigated. THEORY AND METHODS By combining a fmSSFP MRI sequence with a 3D stack-of-stars trajectory, scan efficiency is maximized as spectral information is obtained without intermediate preparation phases. A memory-efficient reconstruction routine is implemented by introducing the low-frequency Fourier transform as a subspace which allows for the formulation of a convex reconstruction problem. The removal of banding artifacts is investigated by comparing the proposed acquisition and reconstruction technique to phase-cycled bSSFP MRI. Aliasing properties of different undersampling schemes are analyzed and water/fat separation is demonstrated by reweighting the reconstructed subspace coefficients to generate virtual spectral responses in a post-processing step. RESULTS A simple root-of-sum-of-squares combination of the reconstructed subspace coefficients yields high-SNR images with the characteristic bSSFP contrast but without banding artifacts. Compared to Golden-Angle trajectories, turn-based sampling schemes were superior in minimizing aliasing across reconstructed subspace coefficients. Water/fat separated images of the human knee were obtained by reweighting subspace coefficients. CONCLUSIONS The novel subspace-based fmSSFP MRI technique emerges as a time-efficient alternative to phase-cycled bSFFP. The method does not need intermediate preparation phases, offers high SNR and avoids banding artifacts. Reweighting of the reconstructed subspace coefficients allows for generating virtual spectral responses with applications to water/fat separation.
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Affiliation(s)
- Volkert Roeloffs
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
| | - Sebastian Rosenzweig
- Institute for Diagnostic and Interventional Radiology, University Medical Center, Göttingen, Germany.,German Centre for Cardiovascular Research (DZHK), Göttingen, Germany
| | - H Christian M Holme
- Institute for Diagnostic and Interventional Radiology, University Medical Center, Göttingen, Germany.,German Centre for Cardiovascular Research (DZHK), Göttingen, Germany
| | - Martin Uecker
- Institute for Diagnostic and Interventional Radiology, University Medical Center, Göttingen, Germany.,German Centre for Cardiovascular Research (DZHK), Göttingen, Germany
| | - Jens Frahm
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany.,German Centre for Cardiovascular Research (DZHK), Göttingen, Germany
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10
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Matsumoto K, Yokota H, Mukai H, Masuda Y, Uno T, Miyati T. Merging images with different central frequencies reduces banding artifacts in balanced steady-state free precession magnetic resonance cisternography. J Appl Clin Med Phys 2018; 19:234-243. [PMID: 30288917 PMCID: PMC6236844 DOI: 10.1002/acm2.12468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 08/25/2018] [Accepted: 09/09/2018] [Indexed: 11/29/2022] Open
Abstract
Purpose The aim of this study was to evaluate the utility of merged balanced steady‐state free precession (bSSFP) magnetic resonance cisternography images. Materials and Methods Twenty ears of 10 healthy volunteers (six men, four women; mean age ± standard deviation, 26.7 ± 1.6 yr) and 10 patients (two men, eight women; mean age, 46.3 ± 10.9 yr) with neoplasm around the sella turcica were included. Two different devices (A and B) were used to confirm the versatility of our method for MR devices with different local magnetic field homogeneity. Images with different central frequencies (±10, ±20, ±30, ±40, and ±50 Hz) were merged with the maximum magnitude of corresponding pixels from the images acquired using both devices. Two neuroradiologists visually graded the image quality of 11 sites in the inner ear and three sites around the sella turcica (scale: 0–2) and compared the quality with that of the corresponding basic image (0 Hz). Results The image quality was better in merged images of the vestibule, superior semicircular canal (SCC), posterior SCC, and horizontal SCC (P = 0.005 to 0.020 mainly at ±40 and ±50 Hz on devices A and B), as well as in merged images of the sella turcica and right cavernous sinus (±50 Hz, P = 0.003 and 0.020 on device B, respectively), than it was in the corresponding basic images. Conclusions The maximum magnitude merging of images with different central frequencies makes it possible to reduce banding artifacts on bSSFP images without the need for special pulse sequences and image processing programs.
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Affiliation(s)
- Koji Matsumoto
- Department of Radiology, Chiba University Hospital, Chiba, Japan.,Division of Health Sciences, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Hajime Yokota
- Diagnostic Radiology and Radiation Oncology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Hiroki Mukai
- Diagnostic Radiology and Radiation Oncology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Yoshitada Masuda
- Department of Radiology, Chiba University Hospital, Chiba, Japan
| | - Takashi Uno
- Diagnostic Radiology and Radiation Oncology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Tosiaki Miyati
- Division of Health Sciences, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan
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11
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Kim J, Seo H, So S, Park H. A multicontrast imaging method using steady-state free precession with alternating RF flip angles. Magn Reson Med 2018; 80:1341-1351. [DOI: 10.1002/mrm.27342] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/20/2018] [Accepted: 04/12/2018] [Indexed: 11/08/2022]
Affiliation(s)
- Joonsoo Kim
- Department of Electrical Engineering; Korea Advanced Institute of Science and Technology; Daejeon Republic of Korea
| | - Hyunseok Seo
- Department of Electrical Engineering; Korea Advanced Institute of Science and Technology; Daejeon Republic of Korea
| | - Seohee So
- Department of Electrical Engineering; Korea Advanced Institute of Science and Technology; Daejeon Republic of Korea
| | - HyunWook Park
- Department of Electrical Engineering; Korea Advanced Institute of Science and Technology; Daejeon Republic of Korea
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12
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Slawig A, Wech T, Ratz V, Neubauer H, Bley T, Köstler H. Frequency-modulated bSSFP for phase-sensitive separation of water and fat. Magn Reson Imaging 2018; 53:82-88. [PMID: 29902564 DOI: 10.1016/j.mri.2018.06.005] [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: 12/05/2017] [Revised: 04/27/2018] [Accepted: 06/10/2018] [Indexed: 10/28/2022]
Abstract
Our study proposes the use of a frequency-modulated acquisition which suppresses banding artefacts in combination with a phase-sensitive water-fat separation algorithm. The performance of the phase-sensitive separation for standard bSSFP, complex sum combination thereof, and frequency-modulated bSSFP were compared in in vivo measurements of the upper and lower legs at 1.5 and 3 T. It is shown, that the standard acquisition suffered from banding artefacts and major swaps between tissues. The dual-acquisition bSSFP could alleviate banding artefacts and only minor swaps occurred, but it comes at the expense of a doubled acquisition. In the frequency-modulated acquisitions all banding artefacts and the associated phase jumps were eliminated and no swaps between tissues occurred. It therefore provides a means to robustly separate water and fat, in one single radial bSSFP scan, using the phase-sensitive approach, even in the presence of high field inhomogeneities.
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Affiliation(s)
- Anne Slawig
- University of Würzburg, Department of Diagnostic and Interventional Radiology, Oberdürrbacher Str. 6, 97080 Würzburg, Germany.
| | - Tobias Wech
- University of Würzburg, Department of Diagnostic and Interventional Radiology, Oberdürrbacher Str. 6, 97080 Würzburg, Germany
| | - Valentin Ratz
- University of Würzburg, Department of Diagnostic and Interventional Radiology, Oberdürrbacher Str. 6, 97080 Würzburg, Germany
| | - Henning Neubauer
- University of Würzburg, Department of Diagnostic and Interventional Radiology, Oberdürrbacher Str. 6, 97080 Würzburg, Germany; SRH Clinic of Radiology, Albert-Schweitzer-Str. 2, 98527 Suhl, Germany
| | - Thorsten Bley
- University of Würzburg, Department of Diagnostic and Interventional Radiology, Oberdürrbacher Str. 6, 97080 Würzburg, Germany
| | - Herbert Köstler
- University of Würzburg, Department of Diagnostic and Interventional Radiology, Oberdürrbacher Str. 6, 97080 Würzburg, Germany
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13
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Hilbert T, Nguyen D, Thiran J, Krueger G, Kober T, Bieri O. True constructive interference in the steady state (trueCISS). Magn Reson Med 2017; 79:1901-1910. [DOI: 10.1002/mrm.26836] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 06/01/2017] [Accepted: 06/22/2017] [Indexed: 11/11/2022]
Affiliation(s)
- Tom Hilbert
- Advanced Clinical Imaging Technology (HC CEMEA SUI DI PI), Siemens Healthcare AGLausanne Switzerland
- LTS5, École Polytechnique Fédérale de LausanneLausanne Switzerland
- Department of RadiologyUniversity Hospital (CHUV)Lausanne Switzerland
| | - Damien Nguyen
- Division of Radiological PhysicsDepartment of Radiology, University Hospital Basel, University of BaselBasel Switzerland
- Department of Biomedical EngineeringUniversity of BaselBasel Switzerland
| | - Jean‐Philippe Thiran
- LTS5, École Polytechnique Fédérale de LausanneLausanne Switzerland
- Department of RadiologyUniversity Hospital (CHUV)Lausanne Switzerland
| | - Gunnar Krueger
- LTS5, École Polytechnique Fédérale de LausanneLausanne Switzerland
- Department of RadiologyUniversity Hospital (CHUV)Lausanne Switzerland
- Siemens Medical Solutions USABoston Massachusetts USA
| | - Tobias Kober
- Advanced Clinical Imaging Technology (HC CEMEA SUI DI PI), Siemens Healthcare AGLausanne Switzerland
- LTS5, École Polytechnique Fédérale de LausanneLausanne Switzerland
- Department of RadiologyUniversity Hospital (CHUV)Lausanne Switzerland
| | - Oliver Bieri
- Division of Radiological PhysicsDepartment of Radiology, University Hospital Basel, University of BaselBasel Switzerland
- Department of Biomedical EngineeringUniversity of BaselBasel Switzerland
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14
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Kim JW, Kim SG, Park SH. Phase imaging with multiple phase-cycled balanced steady-state free precession at 9.4 T. NMR IN BIOMEDICINE 2017; 30:e3699. [PMID: 28187250 DOI: 10.1002/nbm.3699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 12/23/2016] [Accepted: 12/29/2016] [Indexed: 06/06/2023]
Abstract
While phase imaging with a gradient echo (GRE) sequence is popular, phase imaging with balanced steady-state free precession (bSSFP) has been underexplored. The purpose of this study was to investigate anatomical and functional phase imaging with multiple phase-cycled bSSFP, in expectation of increasing spatial coverage of steep phase-change regions of bSSFP. Eight different dynamic 2D pass-band bSSFP studies at four phase-cycling (PC) angles and two TE /TR values were performed on rat brains at 9.4 T with electrical forepaw stimulation, in comparison with dynamic 2D GRE. Anatomical and functional phase images were obtained by averaging the dynamic phase images and mapping correlation between the dynamic images and the stimulation paradigm, and were compared with their corresponding magnitude images. Phase imaging with 3D pass-band and 3D transition-band bSSFP was also performed for comparison with 3D GRE phase imaging. Two strategies of combining the multiple phase-cycled bSSFP phase images were also proposed. Contrast between white matter and gray matter in bSSFP phase images significantly varied with PC angle and became twice as high as that of GRE phase images at a specific PC angle. With the same total scan time, the combined bSSFP phase images provided stronger phase contrast and visualized neuronal fiber-like structures more clearly than the GRE phase images. The combined phase images of both 3D pass-band and 3D transition-band bSSFP showed phase contrasts stronger than those of the GRE phase images in overall brain regions, even at a longer TE of 20 ms. In contrast, phase functional MRI (fMRI) signals were weak overall and mostly located in draining veins for both bSSFP and GRE. Multiple phase-cycled bSSFP phase imaging is a promising anatomical imaging technique, while its usage as fMRI does not seem desirable with the current approach.
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Affiliation(s)
- Jae-Woong Kim
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Seong-Gi Kim
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, South Korea
- Department of Biomedical Engineering, Sungkyunkwan University, Suwon, South Korea
| | - Sung-Hong Park
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
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15
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Han PK, Park H, Park SH. DC artifact correction for arbitrary phase-cycling sequence. Magn Reson Imaging 2017; 38:21-26. [DOI: 10.1016/j.mri.2016.12.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Revised: 12/15/2016] [Accepted: 12/15/2016] [Indexed: 11/17/2022]
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16
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Kim KH, Park SH. Artificial neural network for suppression of banding artifacts in balanced steady-state free precession MRI. Magn Reson Imaging 2017; 37:139-146. [DOI: 10.1016/j.mri.2016.11.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 11/25/2016] [Indexed: 11/29/2022]
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17
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Shang H, Sukumar S, von Morze C, Bok RA, Marco-Rius I, Kerr A, Reed GD, Milshteyn E, Ohliger MA, Kurhanewicz J, Larson PEZ, Pauly JM, Vigneron DB. Spectrally selective three-dimensional dynamic balanced steady-state free precession for hyperpolarized C-13 metabolic imaging with spectrally selective radiofrequency pulses. Magn Reson Med 2016; 78:963-975. [PMID: 27770458 DOI: 10.1002/mrm.26480] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 08/30/2016] [Accepted: 09/02/2016] [Indexed: 12/12/2022]
Abstract
PURPOSE Balanced steady-state free precession (bSSFP) sequences can provide superior signal-to-noise ratio efficiency for hyperpolarized (HP) carbon-13 (13 C) magnetic resonance imaging by efficiently utilizing the nonrecoverable magnetization, but managing their spectral response is challenging in the context of metabolic imaging. A new spectrally selective bSSFP sequence was developed for fast imaging of multiple HP 13 C metabolites with high spatiotemporal resolution. THEORY AND METHODS This novel approach for bSSFP spectral selectivity incorporates optimized short-duration spectrally selective radiofrequency pulses within a bSSFP pulse train and a carefully chosen repetition time to avoid banding artifacts. RESULTS The sequence enabled subsecond 3D dynamic spectrally selective imaging of 13 C metabolites of copolarized [1-13 C]pyruvate and [13 C]urea at 2-mm isotropic resolution, with excellent spectral selectivity (∼100:1). The sequence was successfully tested in phantom studies and in vivo studies with normal mice. CONCLUSION This sequence is expected to benefit applications requiring dynamic volumetric imaging of metabolically active 13 C compounds at high spatiotemporal resolution, including preclinical studies at high field and, potentially, clinical studies. Magn Reson Med 78:963-975, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Hong Shang
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA.,UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco and University of California, Berkeley, California, USA
| | - Subramaniam Sukumar
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Cornelius von Morze
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Robert A Bok
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Irene Marco-Rius
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Adam Kerr
- Electrical Engineering, Stanford University, Stanford, California, USA
| | | | - Eugene Milshteyn
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA.,UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco and University of California, Berkeley, California, USA
| | - Michael A Ohliger
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - John Kurhanewicz
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA.,UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco and University of California, Berkeley, California, USA
| | - Peder E Z Larson
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA.,UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco and University of California, Berkeley, California, USA
| | - John M Pauly
- Electrical Engineering, Stanford University, Stanford, California, USA
| | - Daniel B Vigneron
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA.,UC Berkeley-UCSF Graduate Program in Bioengineering, University of California, San Francisco and University of California, Berkeley, California, USA
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18
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Revisiting the Potential of Alternating Repetition Time Balanced Steady-State Free Precession Imaging of the Abdomen at 3 T. Invest Radiol 2016; 51:560-8. [DOI: 10.1097/rli.0000000000000275] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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19
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Mazzoli V, Nederveen AJ, Oudeman J, Sprengers A, Nicolay K, Strijkers GJ, Verdonschot N. Water and fat separation in real-time MRI of joint movement with phase-sensitive bSSFP. Magn Reson Med 2016; 78:58-68. [DOI: 10.1002/mrm.26341] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 06/20/2016] [Accepted: 06/20/2016] [Indexed: 01/04/2023]
Affiliation(s)
- Valentina Mazzoli
- Biomedical NMR, Department of Biomedical Engineering; Eindhoven University of Technology; Eindhoven The Netherlands
- Department of Radiology; Academic Medical Center; Amsterdam The Netherlands
- Orthopaedic Research Lab; Radboud University Medical Center; Nijmegen The Netherlands
| | - Aart J. Nederveen
- Department of Radiology; Academic Medical Center; Amsterdam The Netherlands
| | - Jos Oudeman
- Department of Radiology; Academic Medical Center; Amsterdam The Netherlands
| | - Andre Sprengers
- Orthopaedic Research Lab; Radboud University Medical Center; Nijmegen The Netherlands
- Laboratory of Biomechanical Engineering; University of Twente; Enschede The Netherlands
| | - Klaas Nicolay
- Biomedical NMR, Department of Biomedical Engineering; Eindhoven University of Technology; Eindhoven The Netherlands
| | - Gustav J. Strijkers
- Biomedical NMR, Department of Biomedical Engineering; Eindhoven University of Technology; Eindhoven The Netherlands
- Biomedical Engineering and Physics; Academic Medical Center; Amsterdam The Netherlands
| | - Nico Verdonschot
- Orthopaedic Research Lab; Radboud University Medical Center; Nijmegen The Netherlands
- Laboratory of Biomechanical Engineering; University of Twente; Enschede The Netherlands
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20
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Ribot EJ, Wecker D, Trotier AJ, Dallaudière B, Lefrançois W, Thiaudière E, Franconi JM, Miraux S. Water Selective Imaging and bSSFP Banding Artifact Correction in Humans and Small Animals at 3T and 7T, Respectively. PLoS One 2015; 10:e0139249. [PMID: 26426849 PMCID: PMC4591352 DOI: 10.1371/journal.pone.0139249] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 09/09/2015] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION The purpose of this paper is to develop an easy method to generate both fat signal and banding artifact free 3D balanced Steady State Free Precession (bSSFP) images at high magnetic field. METHODS In order to suppress fat signal and bSSFP banding artifacts, two or four images were acquired with the excitation frequency of the water-selective binomial radiofrequency pulse set On Resonance or shifted by a maximum of 3/4TR. Mice and human volunteers were imaged at 7 T and 3 T, respectively to perform whole-body and musculoskeletal imaging. "Sum-Of-Square" reconstruction was performed and combined or not with parallel imaging. RESULTS The frequency selectivity of 1-2-3-2-1 or 1-3-3-1 binomial pulses was preserved after (3/4TR) frequency shifting. Consequently, whole body small animal 3D imaging was performed at 7 T and enabled visualization of small structures within adipose tissue like lymph nodes. In parallel, this method allowed 3D musculoskeletal imaging in humans with high spatial resolution at 3 T. The combination with parallel imaging allowed the acquisition of knee images with ~500 μm resolution images in less than 2 min. In addition, ankles, full head coverage and legs of volunteers were imaged, demonstrating the possible application of the method also for large FOV. CONCLUSION In conclusion, this robust method can be applied in small animals and humans at high magnetic fields. The high SNR and tissue contrast obtained in short acquisition times allows to prescribe bSSFP sequence for several preclinical and clinical applications.
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Affiliation(s)
- Emeline J. Ribot
- Centre de Résonance Magnétique des Systèmes Biologiques, UMR 5536, CNRS/University Bordeaux, Bordeaux, France
- * E-mail:
| | | | - Aurélien J. Trotier
- Centre de Résonance Magnétique des Systèmes Biologiques, UMR 5536, CNRS/University Bordeaux, Bordeaux, France
| | - Benjamin Dallaudière
- Centre de Résonance Magnétique des Systèmes Biologiques, UMR 5536, CNRS/University Bordeaux, Bordeaux, France
| | - William Lefrançois
- Centre de Résonance Magnétique des Systèmes Biologiques, UMR 5536, CNRS/University Bordeaux, Bordeaux, France
| | - Eric Thiaudière
- Centre de Résonance Magnétique des Systèmes Biologiques, UMR 5536, CNRS/University Bordeaux, Bordeaux, France
| | - Jean-Michel Franconi
- Centre de Résonance Magnétique des Systèmes Biologiques, UMR 5536, CNRS/University Bordeaux, Bordeaux, France
| | - Sylvain Miraux
- Centre de Résonance Magnétique des Systèmes Biologiques, UMR 5536, CNRS/University Bordeaux, Bordeaux, France
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21
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Henze Bancroft LC, Strigel RM, Hernando D, Johnson KM, Kelcz F, Kijowski R, Block WF. Utilization of a balanced steady state free precession signal model for improved fat/water decomposition. Magn Reson Med 2015; 75:1269-77. [PMID: 25946145 DOI: 10.1002/mrm.25728] [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: 10/14/2014] [Revised: 03/10/2015] [Accepted: 03/20/2015] [Indexed: 12/21/2022]
Abstract
PURPOSE Chemical shift based fat/water decomposition methods such as IDEAL are frequently used in challenging imaging environments with large B0 inhomogeneity. However, they do not account for the signal modulations introduced by a balanced steady state free precession (bSSFP) acquisition. Here we demonstrate improved performance when the bSSFP frequency response is properly incorporated into the multipeak spectral fat model used in the decomposition process. THEORY AND METHODS Balanced SSFP allows for rapid imaging but also introduces a characteristic frequency response featuring periodic nulls and pass bands. Fat spectral components in adjacent pass bands will experience bulk phase offsets and magnitude modulations that change the expected constructive and destructive interference between the fat spectral components. A bSSFP signal model was incorporated into the fat/water decomposition process and used to generate images of a fat phantom, and bilateral breast and knee images in four normal volunteers at 1.5 Tesla. RESULTS Incorporation of the bSSFP signal model into the decomposition process improved the performance of the fat/water decomposition. CONCLUSION Incorporation of this model allows rapid bSSFP imaging sequences to use robust fat/water decomposition methods such as IDEAL. While only one set of imaging parameters were presented, the method is compatible with any field strength or repetition time.
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Affiliation(s)
- Leah C Henze Bancroft
- University of Wisconsin-Madison, Department of Medical Physics, Wisconsin Institutes for Medical Research, Madison, Wisconsin, USA
| | - Roberta M Strigel
- University of Wisconsin-Madison, Department of Medical Physics, Wisconsin Institutes for Medical Research, Madison, Wisconsin, USA.,University of Wisconsin School of Medicine and Public health, Department of Radiology, Madison, Wisconsin, USA.,University of Wisconsin Carbone Cancer Center, Wisconsin Institutes for Medical Research, Madison, Wisconsin, USA
| | - Diego Hernando
- University of Wisconsin-Madison, Department of Radiology, Wisconsin Institutes for Medical Research, Madison, Wisconsin, USA
| | - Kevin M Johnson
- University of Wisconsin-Madison, Department of Medical Physics, Wisconsin Institutes for Medical Research, Madison, Wisconsin, USA
| | - Frederick Kelcz
- University of Wisconsin School of Medicine and Public health, Department of Radiology, Madison, Wisconsin, USA
| | - Richard Kijowski
- University of Wisconsin School of Medicine and Public health, Department of Radiology, Madison, Wisconsin, USA
| | - Walter F Block
- University of Wisconsin-Madison, Department of Medical Physics, Wisconsin Institutes for Medical Research, Madison, Wisconsin, USA.,University of Wisconsin-Madison, Department of Radiology, Wisconsin Institutes for Medical Research, Madison, Wisconsin, USA.,University of Wisconsin-Madison, Department of Biomedical Engineering, Wisconsin Institutes for Medical Research, Madison, Wisconsin
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22
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Çukur T. Spectrally selective imaging with wideband balanced steady-state free precession MRI. Magn Reson Med 2015; 75:1132-41. [PMID: 25846631 DOI: 10.1002/mrm.25700] [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: 10/10/2014] [Revised: 01/26/2015] [Accepted: 02/25/2015] [Indexed: 11/10/2022]
Abstract
PURPOSE Unwanted, bright fat signals in balanced steady-state free precession sequences are commonly suppressed using spectral shaping. Here, a new spectral-shaping method is proposed to significantly improve the uniformity of stopband suppression without compromising the level of passband signals. METHODS The proposed method combines binomial-pattern excitation pulses with a wideband balanced steady-state free precession sequence kernel. It thereby increases the frequency separation between the centers of pass and stopbands by π radians, enabling improved water-fat contrast. Simulations were performed to find the optimal flip angles and subpulse spacing for the binomial pulses that maximize contrast and signal efficiency. RESULTS Comparisons with a conventional binomial balanced steady-state free precession sequence were performed in simulations as well as phantom and in vivo experiments at 1.5 T and 3 T. Enhanced fat suppression is demonstrated in vivo with an average improvement of 58% in blood-fat and 68% in muscle-fat contrast (P < 0.001, Wilcoxon signed-rank test). CONCLUSION The proposed binomial wideband balanced steady-state free precession method is a promising candidate for spectrally selective imaging with enhanced reliability against field inhomogeneities.
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Affiliation(s)
- Tolga Çukur
- Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey.,National Magnetic Resonance Research Center, Bilkent University, Ankara, Turkey
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23
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Gao Y, Chen Y, Ma D, Jiang Y, Herrmann KA, Vincent JA, Dell KM, Drumm ML, Brady-Kalnay SM, Griswold MA, Flask CA, Lu L. Preclinical MR fingerprinting (MRF) at 7 T: effective quantitative imaging for rodent disease models. NMR IN BIOMEDICINE 2015; 28:384-394. [PMID: 25639694 PMCID: PMC4396690 DOI: 10.1002/nbm.3262] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 12/18/2014] [Accepted: 12/22/2014] [Indexed: 05/29/2023]
Abstract
High-field preclinical MRI scanners are now commonly used to quantitatively assess disease status and the efficacy of novel therapies in a wide variety of rodent models. Unfortunately, conventional MRI methods are highly susceptible to respiratory and cardiac motion artifacts resulting in potentially inaccurate and misleading data. We have developed an initial preclinical 7.0-T MRI implementation of the highly novel MR fingerprinting (MRF) methodology which has been described previously for clinical imaging applications. The MRF technology combines a priori variation in the MRI acquisition parameters with dictionary-based matching of acquired signal evolution profiles to simultaneously generate quantitative maps of T1 and T2 relaxation times and proton density. This preclinical MRF acquisition was constructed from a fast imaging with steady-state free precession (FISP) MRI pulse sequence to acquire 600 MRF images with both evolving T1 and T2 weighting in approximately 30 min. This initial high-field preclinical MRF investigation demonstrated reproducible and differentiated estimates of in vitro phantoms with different relaxation times. In vivo preclinical MRF results in mouse kidneys and brain tumor models demonstrated an inherent resistance to respiratory motion artifacts as well as sensitivity to known pathology. These results suggest that MRF methodology may offer the opportunity for the quantification of numerous MRI parameters for a wide variety of preclinical imaging applications.
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Affiliation(s)
- Ying Gao
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106
| | - Yong Chen
- Department of Radiology, Case Western Reserve University, Cleveland, OH 44106
| | - Dan Ma
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106
| | - Yun Jiang
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106
| | - Kelsey A. Herrmann
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, OH 44106
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH 44106
| | - Jason A. Vincent
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, OH 44106
| | - Katherine M. Dell
- CWRU Center for the Study of Kidney Disease and Biology, MetroHealth Campus, Case Western Reserve University, Cleveland, OH 44109
- Pediatric Institute, Cleveland Clinic Foundation, Cleveland, OH 44106
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH 44106
| | - Mitchell L. Drumm
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH 44106
- Department of Genetics, Case Western Reserve University, Cleveland, OH 44106
| | - Susann M. Brady-Kalnay
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, OH 44106
- Department of Neurosciences, Case Western Reserve University, Cleveland, OH 44106
| | - Mark A. Griswold
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106
- Department of Radiology, Case Western Reserve University, Cleveland, OH 44106
| | - Chris A. Flask
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106
- Department of Radiology, Case Western Reserve University, Cleveland, OH 44106
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH 44106
| | - Lan Lu
- Department of Radiology, Case Western Reserve University, Cleveland, OH 44106
- Department of Urology, Case Western Reserve University, Cleveland, OH 44106
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24
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Shapiro LM, Matzat SJ, Gold GE. Functional magnetic resonance imaging. Rheumatology (Oxford) 2015. [DOI: 10.1016/b978-0-323-09138-1.00041-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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25
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Cukur T. Accelerated phase-cycled SSFP imaging with compressed sensing. IEEE TRANSACTIONS ON MEDICAL IMAGING 2015; 34:107-115. [PMID: 25134078 DOI: 10.1109/tmi.2014.2346814] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Balanced steady-state free precession (SSFP) imaging suffers from irrecoverable signal losses, known as banding artifacts, in regions of large B0 field inhomogeneity. A common solution is to acquire multiple phase-cycled images each with a different frequency sensitivity, such that the location of banding artifacts are shifted in space. These images are then combined to alleviate signal loss across the entire field-of-view. Although high levels of artifact suppression are viable using a large number of images, this is a time costly process that limits clinical utility. Here, we propose to accelerate individual acquisitions such that the overall scan time is equal to that of a single SSFP acquisition. Aliasing artifacts and noise are minimized by using a variable-density random sampling pattern in k-space, and by generating disjoint sampling patterns for separate acquisitions. A sparsity-enforcing method is then used for image reconstruction. Demonstrations on realistic brain phantom images, and in vivo brain and knee images are provided. In all cases, the proposed technique enables robust SSFP imaging in the presence of field inhomogeneities without prolonging scan times.
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26
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Quist B, Hargreaves BA, Daniel BL, Saranathan M. Balanced SSFP Dixon imaging with banding-artifact reduction at 3 Tesla. Magn Reson Med 2014; 74:706-15. [PMID: 25227766 DOI: 10.1002/mrm.25449] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 08/20/2014] [Accepted: 08/21/2014] [Indexed: 01/10/2023]
Abstract
PURPOSE To develop a three-dimensional (3D) balanced steady-state free-precession (bSSFP) two-point Dixon method with banding-artifact suppression to offer robust high-resolution 3D bright-fluid imaging. METHODS A complex sum reconstruction that combines phase-cycled bSSFP images acquired at specific echo times for robust fat/water separation without banding was investigated and compared with a magnitude-based method. Bloch simulations using both single-peak and multiple-peak fat models were performed to predict the performance of these methods for a wide range of echo times and repetition times. The quality and degree of fat/water separation was evaluated in both simulations and using in vivo imaging. RESULTS Simulations predicted that both effective banding-artifact suppression and substantial improvements in fat/water separation are possible at echo times that are different from conventional echo times, enabling improved spatial resolution. Comparisons between various echo times and repetition times in vivo validated the improved fat/water separation and effective banding-artifact removal predicted by the simulations. CONCLUSION The proposed complex sum Dixon 3D bSSFP method is able to effectively separate fat and water at different sets of echo times, while removing banding-artifacts, providing a fast, high-resolution, T2 -like sequence without blurring.
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Affiliation(s)
- Brady Quist
- Department of Radiology, Stanford University, Stanford, California, USA.,Department of Electrical Engineering, Stanford University, Stanford, California, USA
| | | | - Bruce L Daniel
- Department of Radiology, Stanford University, Stanford, California, USA
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Gao Y, Goodnough CL, Erokwu BO, Farr GW, Darrah R, Lu L, Dell KM, Yu X, Flask CA. Arterial spin labeling-fast imaging with steady-state free precession (ASL-FISP): a rapid and quantitative perfusion technique for high-field MRI. NMR IN BIOMEDICINE 2014; 27:996-1004. [PMID: 24891124 PMCID: PMC4110188 DOI: 10.1002/nbm.3143] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 04/28/2014] [Accepted: 04/30/2014] [Indexed: 05/03/2023]
Abstract
Arterial spin labeling (ASL) is a valuable non-contrast perfusion MRI technique with numerous clinical applications. Many previous ASL MRI studies have utilized either echo-planar imaging (EPI) or true fast imaging with steady-state free precession (true FISP) readouts, which are prone to off-resonance artifacts on high-field MRI scanners. We have developed a rapid ASL-FISP MRI acquisition for high-field preclinical MRI scanners providing perfusion-weighted images with little or no artifacts in less than 2 s. In this initial implementation, a flow-sensitive alternating inversion recovery (FAIR) ASL preparation was combined with a rapid, centrically encoded FISP readout. Validation studies on healthy C57/BL6 mice provided consistent estimation of in vivo mouse brain perfusion at 7 and 9.4 T (249 ± 38 and 241 ± 17 mL/min/100 g, respectively). The utility of this method was further demonstrated in the detection of significant perfusion deficits in a C57/BL6 mouse model of ischemic stroke. Reasonable kidney perfusion estimates were also obtained for a healthy C57/BL6 mouse exhibiting differential perfusion in the renal cortex and medulla. Overall, the ASL-FISP technique provides a rapid and quantitative in vivo assessment of tissue perfusion for high-field MRI scanners with minimal image artifacts.
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Affiliation(s)
- Ying Gao
- Department of Radiology, Case Western Reserve University, Cleveland, OH 44106
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106
| | - Candida L. Goodnough
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106
| | | | - George W. Farr
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106
- Aeromics, LLC, Cleveland, OH 44106
| | - Rebecca Darrah
- Frances Payne Bolton School of Nursing, Case Western Reserve University, Cleveland, OH 44106
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH 44106
| | - Lan Lu
- Department of Radiology, Case Western Reserve University, Cleveland, OH 44106
- Department of Urology, Case Western Reserve University, Cleveland, OH 44106
| | - Katherine M. Dell
- CWRU Center for the Study of Kidney Disease and Biology, MetroHealth Campus, Case Western Reserve University, Cleveland, OH 44109
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH 44106
| | - Xin Yu
- Department of Radiology, Case Western Reserve University, Cleveland, OH 44106
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106
| | - Chris A. Flask
- Department of Radiology, Case Western Reserve University, Cleveland, OH 44106
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH 44106
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Liu J, Nguyen TD, Zhu Y, Spincemaille P, Prince MR, Weinsaft JW, Saloner D, Wang Y. Self-gated free-breathing 3D coronary CINE imaging with simultaneous water and fat visualization. PLoS One 2014; 9:e89315. [PMID: 24586682 PMCID: PMC3930724 DOI: 10.1371/journal.pone.0089315] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 01/22/2014] [Indexed: 11/17/2022] Open
Abstract
The aim of this study was to develop a novel technique for acquiring 3-dimensional (3D) coronary CINE magnetic resonance images with both water and fat visualization during free breathing and without external respiratory or cardiac gating. The implemented multi-echo hybrid 3D radial balanced Steady-State Free Precession (SSFP) sequence has an efficient data acquisition and is robust against motion. The k-space center along the slice encoding direction was repeatedly acquired to derive both respiratory and cardiac self-gating signals without an increase in scan time, enabling a free-breathing acquisition. The multi-echo acquisition allowed image reconstruction with water-fat separation, providing improved visualization of the coronary artery lumen. Ten healthy subjects were imaged successfully at 1.5 T, achieving a spatial resolution of 1.0×1.0×3.0 mm3 and scan time of about 5 minutes. The proposed imaging technique provided coronary vessel depiction comparable to that obtained with conventional breath-hold imaging and navigator gated free-breathing imaging.
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Affiliation(s)
- Jing Liu
- Department of Radiology, Weill Cornell Medical College, New York, New York, United States of America ; Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, United States of America
| | - Thanh D Nguyen
- Department of Radiology, Weill Cornell Medical College, New York, New York, United States of America
| | - Yanchun Zhu
- Department of Radiology, Weill Cornell Medical College, New York, New York, United States of America
| | - Pascal Spincemaille
- Department of Radiology, Weill Cornell Medical College, New York, New York, United States of America
| | - Martin R Prince
- Department of Radiology, Weill Cornell Medical College, New York, New York, United States of America
| | - Jonathan W Weinsaft
- Department of Radiology, Weill Cornell Medical College, New York, New York, United States of America
| | - David Saloner
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, United States of America
| | - Yi Wang
- Department of Radiology, Weill Cornell Medical College, New York, New York, United States of America
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29
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Al saleh H, Hernandez L, Lee KS, Rosas HG, Block WF, Kijowski R. Rapid isotropic resolution cartilage assessment using radial alternating repetition time balanced steady-state free-precession imaging. J Magn Reson Imaging 2013; 40:796-803. [PMID: 24151247 DOI: 10.1002/jmri.24425] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 08/27/2013] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To compare a balanced steady-state free-precession sequence with a radial k-space trajectory and alternating repetition time fat suppression (Radial-ATR) with other currently used fat-suppressed 3D sequences for evaluating the articular cartilage of the knee joint at 3.0T. MATERIALS AND METHODS Radial-ATR, fast spin-echo (FSE-Cube), gradient recall-echo acquired in the steady-state (GRASS), and spoiled gradient recall-echo (SPGR) sequences with similar voxel volumes and identical scan times were performed at 3.0T on both knee joints of five volunteers. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) measurements were performed for all sequences using a double acquisition method and compared using Mann-Whitney Wilcoxon tests. Radial-ATR sequences with 0.3 mm and 0.4 mm isotropic resolution were also performed on the knee joints of seven volunteers and three patients with osteoarthritis. RESULTS Average SNR values for cartilage, synovial fluid, and bone marrow were 54.7, 153.3, and 12.9, respectively, for Radial ATR, 30.8, 44.1, and 1.9, respectively, for FSE-Cube, 13.3, 46.9, and 3.3, respectively, for GRASS, and 19.1, 8.1, and 2.1, respectively, for SPGR. Average CNR values between cartilage and synovial fluid and between cartilage and bone marrow were 98.6 and 41.8, respectively, for VIPR-ATR, 13.4 and 28.8, respectively, for FSE-Cube, 33.6 and 10.0, respectively, for GRASS, and 11.0 and 16.9, respectively, for SPGR. Radial-ATR had significantly higher (P < 0.001) cartilage, synovial fluid, and bone marrow SNR and significantly higher (P < 0.01) CNR between cartilage and synovial fluid and between cartilage and bone marrow than FSE-Cube, GRASS, and SPGR. Radial-ATR provided excellent visualization of articular cartilage at high isotropic resolution with no image degradation due to off-resonance banding artifacts. CONCLUSION Radial-ATR had superior SNR efficiency to other fat-suppressed 3D cartilage imaging sequences and produced high isotropic resolution images of the knee joint which could be used for evaluating articular cartilage at 3.0T.
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Affiliation(s)
- Habib Al saleh
- Department of Medical Physics, University of Wisconsin, Madison, Wisconsin, USA
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30
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Bultman EM, Klaers J, Johnson KM, François CJ, Schiebler ML, Reeder SB, Block WF. Non-contrast enhanced 3D SSFP MRA of the renal allograft vasculature: a comparison between radial linear combination and Cartesian inflow-weighted acquisitions. Magn Reson Imaging 2013; 32:190-5. [PMID: 24246390 DOI: 10.1016/j.mri.2013.10.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 09/03/2013] [Accepted: 10/07/2013] [Indexed: 11/20/2022]
Abstract
Renal transplant patients often require imaging to ensure appropriate graft placement, to assess integrity of transplant vessel anastomosis and to evaluate for stenosis that can be a cause of graft failure. Because there is risk for nephrogenic systemic fibrosis in the setting of renal insufficiency, the use of non-contrast MRA in these patients is helpful. In this study, the ability of two non-contrast MRA methods - 3D radial linear combination balanced SSFP (VIPR-SSFP) and inflow-weighted Cartesian SSFP (IFIR) - to visualize the transplant renal vessels is compared. Twenty-one renal transplant patients were scanned using the VIPR-SSFP and IFIR sequences. Diagnostic efficacy of the sequences was scored using a four point Likert scale according to the following criteria: overall image quality, fat suppression, and arterial/venous visualization quality. Average scores for each criterion were compared using the Wilcoxon signed-rank test. In addition to significantly improved venous visualization, the VIPR-SSFP sequence provided significantly improved fat suppression quality (p<0.03) compared to IFIR. VIPR-SSFP also identified several pathologies such as renal arterial pseudoaneurysm that were not visible on the IFIR images. However, IFIR afforded superior quality of arterial visualization (p<0.005). These two methods of non-contrast MR imaging each have significant strengths and are complementary to each other in evaluating the vasculature of renal allografts.
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Affiliation(s)
- Eric M Bultman
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI.
| | - Jessica Klaers
- Department of Medical Physics, University of Wisconsin, Madison, WI
| | - Kevin M Johnson
- Department of Medical Physics, University of Wisconsin, Madison, WI
| | | | | | - Scott B Reeder
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI; Department of Medical Physics, University of Wisconsin, Madison, WI; Department of Radiology, University of Wisconsin, Madison, WI; Department of Medicine, University of Wisconsin, Madison, WI
| | - Walter F Block
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI; Department of Medical Physics, University of Wisconsin, Madison, WI; Department of Radiology, University of Wisconsin, Madison, WI
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31
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Rosas H, Kijowski R. Volumetric magnetic resonance imaging of the musculoskeletal system. Semin Roentgenol 2013; 48:140-7. [PMID: 23452461 DOI: 10.1053/j.ro.2012.11.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Humberto Rosas
- Department of Radiology, Musculoskeletal Division, University of Wisconsin School of Medicine and Public Health, Madison, WI 53792-3252, USA.
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32
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Pelot NA, Bowen CV. Quantification of superparamagnetic iron oxide using inversion recovery balanced steady-state free precession. Magn Reson Imaging 2013; 31:953-60. [PMID: 23601361 DOI: 10.1016/j.mri.2013.03.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 02/19/2013] [Accepted: 03/09/2013] [Indexed: 11/29/2022]
Abstract
Cellular and molecular MRI trafficking studies using superparamagnetic iron oxide (SPIO) have greatly improved non-invasive investigations of disease progression and drug efficacy, but thus far, these studies have largely been restricted to qualitative assessment of hypo- or hyperintense areas near SPIO. In this work, SPIO quantification using inversion recovery balanced steady-state free precession (IR-bSSFP) was demonstrated at 3T by extracting R2 values from a monoexponential model (P. Schmitt et al., 2004). A low flip angle was shown to reduce the apparent recovery rate of the IR-bSSFP time course, thus extending the dynamic range of quantification. However, low flip angle acquisitions preclude the use of traditional methods for combining RF phase-cycled images to reduce banding artifacts arising from off-resonance due to B0 inhomogeneity. To achieve R2 quantification of SPIO, we present a new algorithm applicable to low flip angle IR-bSSFP acquisitions that is specifically designed to identify on-resonance acquisitions. We demonstrate in this work, using both theoretical and empirical methods, that the smallest estimated R2 from multiple RF phase-cycled acquisitions correspond well to the on-resonance time course. Using this novel minimum R2 algorithm, homogeneous R2 maps and linear R2 calibration curves were created up to 100μg(Fe)/mL with 20° flip angles, despite substantial B0 inhomogeneity. In addition, we have shown this technique to be feasible for pre-clinical research: the minimum R2 algorithm was resistant to off-resonance in a single slice mouse R2 map, whereas maximum intensity projection resulted in banding artifacts and overestimated R2 values. With the application of recent advances in accelerated acquisitions, IR-bSSFP has the potential to quantify SPIO in vivo, thus providing important information for oncology, immunology, and regenerative medicine MRI studies.
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Affiliation(s)
- Nicole A Pelot
- Department of Biomedical Engineering, Duke University, Room 136 Hudson Hall, Box 90281, Durham, NC 27708-0281, USA.
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Moran CJ, Brodsky EK, Bancroft LH, Reeder SB, Yu H, Kijowski R, Engel D, Block WF. High-resolution 3D radial bSSFP with IDEAL. Magn Reson Med 2013; 71:95-104. [PMID: 23504943 DOI: 10.1002/mrm.24633] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 12/16/2012] [Accepted: 12/18/2012] [Indexed: 12/19/2022]
Abstract
Radial trajectories facilitate high-resolution balanced steady state free precession (bSSFP) because the efficient gradients provide more time to extend the trajectory in k-space. A number of radial bSSFP methods that support fat-water separation have been developed; however, most of these methods require an environment with limited B0 inhomogeneity. In this work, high-resolution bSSFP with fat-water separation is achieved in more challenging B0 environments by combining a 3D radial trajectory with the IDEAL chemical species separation method. A method to maintain very high resolution within the timing constraints of bSSFP and IDEAL is described using a dual-pass pulse sequence. The sampling of a unique set of radial lines at each echo time is investigated as a means to circumvent the longer scan time that IDEAL incurs as a multiecho acquisition. The manifestation of undersampling artifacts in this trajectory and their effect on chemical species separation are investigated in comparison to the case in which each echo samples the same set of radial lines. This new bSSFP method achieves 0.63 mm isotropic resolution in a 5-min scan and is demonstrated in difficult in vivo imaging environments, including the breast and a knee with ACL reconstruction hardware at 1.5 T.
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Affiliation(s)
- Catherine J Moran
- Department of Medical Physics, University of Wisconsin, Madison, Wisconsin, USA
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34
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Hargreaves BA. Rapid gradient-echo imaging. J Magn Reson Imaging 2012; 36:1300-13. [PMID: 23097185 DOI: 10.1002/jmri.23742] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 05/24/2012] [Indexed: 11/07/2022] Open
Abstract
Gradient-echo sequences are widely used in magnetic resonance imaging (MRI) for numerous applications ranging from angiography to perfusion to functional MRI. Compared with spin-echo techniques, the very short repetition times of gradient-echo methods enable very rapid 2D and 3D imaging, but also lead to complicated "steady states." Signal and contrast behavior can be described graphically and mathematically, and depends strongly on the type of spoiling: fully balanced (no spoiling), gradient spoiling, or radiofrequency (RF)-spoiling. These spoiling options trade off between high signal and pure T(1) contrast, while the flip angle also affects image contrast in all cases, both of which can be demonstrated theoretically and in image examples. As with spin-echo sequences, magnetization preparation can be added to gradient-echo sequences to alter image contrast. Gradient-echo sequences are widely used for numerous applications such as 3D perfusion imaging, functional MRI, cardiac imaging, and MR angiography.
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Affiliation(s)
- Brian A Hargreaves
- Department of Radiology, Stanford University, Stanford, California, USA.
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35
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Miller KL. FMRI using balanced steady-state free precession (SSFP). Neuroimage 2012; 62:713-9. [PMID: 22036996 PMCID: PMC3398389 DOI: 10.1016/j.neuroimage.2011.10.040] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 10/11/2011] [Accepted: 10/12/2011] [Indexed: 10/26/2022] Open
Abstract
Steady-state free precession (SSFP) is a highly-efficient MRI pulse sequence that has been a fairly recent arrival in the functional MRI realm. Several methods for using balanced SSFP to detect the BOLD signal have been proposed to date and will be discussed in this review. After a brief introduction to the general properties of SSFP, this review describes the quite different approaches of transition-band and pass-band SSFP in terms of functional contrast mechanism. It then discusses the potential advantages of these techniques, followed by their challenges and shortcomings. Finally, it gives an overview of some applications considered to date and the author's perspective on where these techniques are headed. In the spirit of this special issue, the author also includes some of the personal history underlying her own explorations in this area.
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36
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Hu HH, Börnert P, Hernando D, Kellman P, Ma J, Reeder S, Sirlin C. ISMRM workshop on fat-water separation: insights, applications and progress in MRI. Magn Reson Med 2012; 68:378-88. [PMID: 22693111 PMCID: PMC3575097 DOI: 10.1002/mrm.24369] [Citation(s) in RCA: 134] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 05/14/2012] [Accepted: 05/16/2012] [Indexed: 12/12/2022]
Abstract
Approximately 130 attendees convened on February 19-22, 2012 for the first ISMRM-sponsored workshop on water-fat imaging. The motivation to host this meeting was driven by the increasing number of research publications on this topic over the past decade. The scientific program included an historical perspective and a discussion of the clinical relevance of water-fat MRI, a technical description of multiecho pulse sequences, a review of data acquisition and reconstruction algorithms, a summary of the confounding factors that influence quantitative fat measurements and the importance of MRI-based biomarkers, a description of applications in the heart, liver, pancreas, abdomen, spine, pelvis, and muscles, an overview of the implications of fat in diabetes and obesity, a discussion on MR spectroscopy, a review of childhood obesity, the efficacy of lifestyle interventional studies, and the role of brown adipose tissue, and an outlook on federal funding opportunities from the National Institutes of Health.
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Affiliation(s)
- Houchun Harry Hu
- Departments of Radiology and Electrical Engineering, Children's Hospital Los Angeles, University of Southern California, Los Angeles, California 90027, USA.
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37
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38
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Gonçalves SI, Ziech MLW, Lamerichs R, Stoker J, Nederveen AJ. Optimization of alternating TR-SSFP for fat-suppression in abdominal images at 3T. Magn Reson Med 2011; 67:595-600. [DOI: 10.1002/mrm.23215] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 08/02/2011] [Accepted: 08/22/2011] [Indexed: 12/12/2022]
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Quist B, Hargreaves BA, Cukur T, Morrell GR, Gold GE, Bangerter NK. Simultaneous fat suppression and band reduction with large-angle multiple-acquisition balanced steady-state free precession. Magn Reson Med 2011; 67:1004-12. [PMID: 22038883 DOI: 10.1002/mrm.23076] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2010] [Revised: 05/01/2011] [Accepted: 06/08/2011] [Indexed: 01/13/2023]
Abstract
Balanced steady-state free precession (bSSFP) MRI is a rapid and signal-to-noise ratio-efficient imaging method, but suffers from characteristic bands of signal loss in regions of large field inhomogeneity. Several methods have been developed to reduce the severity of these banding artifacts, typically involving the acquisition of multiple bSSFP datasets (and the accompanying increase in scan time). Fat suppression with bSSFP is also challenging; most existing methods require an additional increase in scan time, and some are incompatible with bSSFP band-reduction techniques. This work was motivated by the need for both robust fat suppression and band reduction in the presence of field inhomogeneity when using bSSFP for flow-independent peripheral angiography. The large flip angles used in this application to improve vessel conspicuity and contrast lead to specific absorption rate considerations, longer repetition times, and increased severity of banding artifacts. In this work, a novel method that simultaneously suppresses fat and reduces bSSFP banding artifact with the acquisition of only two phase-cycled bSSFP datasets is presented. A weighted sum of the two bSSFP acquisitions is taken on a voxel-by-voxel basis, effectively synthesizing an off-resonance profile at each voxel that puts fat in the stop band while keeping water in the pass band. The technique exploits the near-sinusoidal shape of the bSSFP off-resonance spectrum for many tissues at large (>50°) flip angles.
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Affiliation(s)
- Brady Quist
- Department of Electrical and Computer Engineering, Brigham Young University, Provo, UT, USA
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40
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Ingle RR, Cukur T, Nishimura DG. The central signal singularity phenomenon in balanced SSFP and its application to positive-contrast imaging. Magn Reson Med 2011; 67:1673-83. [PMID: 22025426 DOI: 10.1002/mrm.23156] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Revised: 07/20/2011] [Accepted: 07/26/2011] [Indexed: 11/06/2022]
Abstract
Small perturbations of steady-state sequence parameters can induce very large spectral profile deviations that are localized to specific off-resonant frequencies, denoted critical frequencies. Although, a small number of studies have previously considered the use of these highly specific modulations for MR angiography and elastography, many potential applications still remain to be explored. An analysis of this phenomenon using a linear systems technique and a geometric magnetization trajectory technique shows that the critical frequencies correspond to singularities in the steady-state signal equation. An interleaved acquisition combined with a complex difference technique yields a spectral profile containing sharp peaks interleaved with wide stopbands, while a complex sum technique yields a spectral profile similar to that of balanced steady-state free precession. Simulations and phantom experiments are used to demonstrate a novel application of this technique for positive-contrast imaging of superparamagnetic iron-oxide nanoparticles. The technique is shown to yield images with high levels of positive contrast and good water and fat background suppression. The technique can also simultaneously yield images with contrast similar to balanced steady-state free precession.
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Affiliation(s)
- R Reeve Ingle
- Magnetic Resonance Systems Research Laboratory, Department of Electrical Engineering, Stanford University, Stanford, California, USA.
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41
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Kijowski R, Gold GE. Routine 3D magnetic resonance imaging of joints. J Magn Reson Imaging 2011; 33:758-71. [PMID: 21448939 DOI: 10.1002/jmri.22342] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Due to its high spatial resolution and excellent tissue contrast, magnetic resonance imaging (MRI) has become the most commonly used imaging method to evaluate joints. Most musculoskeletal MRI is performed using 2D fast spin-echo sequences. However, 3D sequences have also been used for joint imaging and have the advantage of acquiring thin continuous slices through joints, which reduces the effects of partial volume averaging. With recent advances in MR technology, 3D sequences with isotropic resolution have been developed. These sequences allow high-quality multiplanar reformat images to be obtained following a single acquisition, thereby eliminating the need to repeat sequences with identical tissue contrast in different planes. Preliminary results on the diagnostic performance of 3D isotropic resolution sequences are encouraging. However, additional studies are needed to determine whether these sequences can replace currently used 2D fast spin-echo sequences for providing comprehensive joint assessment in clinical practice.
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Affiliation(s)
- Richard Kijowski
- Department of Radiology, University of Wisconsin, Madison, WI, USA.
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42
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Cukur T, Shimakawa A, Yu H, Hargreaves BA, Hu BS, Nishimura DG, Brittain JH. Magnetization-prepared IDEAL bSSFP: a flow-independent technique for noncontrast-enhanced peripheral angiography. J Magn Reson Imaging 2011; 33:931-9. [PMID: 21448960 DOI: 10.1002/jmri.22479] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
PURPOSE To propose a new noncontrast-enhanced flow-independent angiography sequence based on balanced steady-state free precession (bSSFP) that produces reliable vessel contrast despite the reduced blood flow in the extremities. MATERIALS AND METHODS The proposed technique addresses a variety of factors that can compromise the exam success including insufficient background suppression, field inhomogeneity, and large volumetric coverage requirements. A bSSFP sequence yields reduced signal from venous blood when long repetition times are used. Complex-sum bSSFP acquisitions decrease the sensitivity to field inhomogeneity but retain phase information, so that data can be processed with the Iterative Decomposition of Water and Fat with Echo Asymmetry and Least-Squares Estimation (IDEAL) method for robust fat suppression. Meanwhile, frequent magnetization preparation coupled with parallel imaging reduces the muscle and long-T(1) fluid signals without compromising scan efficiency. RESULTS In vivo flow-independent peripheral angiograms with reliable background suppression and high spatial resolution are produced. Comparisons with phase-sensitive bSSFP angiograms (that yield out-of-phase fat and water signals, and exploit this phase difference to suppress fat) demonstrate enhanced vessel depiction with the proposed technique due to reduced partial-volume effects and improved venous suppression. CONCLUSION Magnetization-prepared complex-sum bSSFP with IDEAL fat/water separation can create reliable flow-independent angiographic contrast in the lower extremities.
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Affiliation(s)
- Tolga Cukur
- Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA.
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43
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Miller KL, Stagg CJ, Douaud G, Jbabdi S, Smith SM, Behrens TEJ, Jenkinson M, Chance SA, Esiri MM, Voets NL, Jenkinson N, Aziz TZ, Turner MR, Johansen-Berg H, McNab JA. Diffusion imaging of whole, post-mortem human brains on a clinical MRI scanner. Neuroimage 2011; 57:167-181. [PMID: 21473920 PMCID: PMC3115068 DOI: 10.1016/j.neuroimage.2011.03.070] [Citation(s) in RCA: 197] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 03/12/2011] [Accepted: 03/25/2011] [Indexed: 11/05/2022] Open
Abstract
Diffusion imaging of post mortem brains has great potential both as a reference for brain specimens that undergo sectioning, and as a link between in vivo diffusion studies and "gold standard" histology/dissection. While there is a relatively mature literature on post mortem diffusion imaging of animals, human brains have proven more challenging due to their incompatibility with high-performance scanners. This study presents a method for post mortem diffusion imaging of whole, human brains using a clinical 3-Tesla scanner with a 3D segmented EPI spin-echo sequence. Results in eleven brains at 0.94 × 0.94 × 0.94 mm resolution are presented, and in a single brain at 0.73 × 0.73 × 0.73 mm resolution. Region-of-interest analysis of diffusion tensor parameters indicate that these properties are altered compared to in vivo (reduced diffusivity and anisotropy), with significant dependence on post mortem interval (time from death to fixation). Despite these alterations, diffusion tractography of several major tracts is successfully demonstrated at both resolutions. We also report novel findings of cortical anisotropy and partial volume effects.
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Affiliation(s)
- Karla L Miller
- FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
| | - Charlotte J Stagg
- FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Gwenaëlle Douaud
- FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Saad Jbabdi
- FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Stephen M Smith
- FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Timothy E J Behrens
- FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Mark Jenkinson
- FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Steven A Chance
- Clinical Neurology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Margaret M Esiri
- Clinical Neurology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Natalie L Voets
- FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Ned Jenkinson
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - Tipu Z Aziz
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
| | - Martin R Turner
- FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Heidi Johansen-Berg
- FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Jennifer A McNab
- A.A.Martinos Centre, Massachusetts General Hospital, Boston, USA
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Rosas HG, Tuite MJ. The current state of imaging the articular cartilage of the upper extremity. Magn Reson Imaging Clin N Am 2011; 19:407-23. [PMID: 21665097 DOI: 10.1016/j.mric.2011.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
MR imaging has increasingly been used to image joints since its inception. Historically, there has been more emphasis on the evaluation of internal derangement rather than cartilaginous disease. This article reviews cartilaginous diseases of the upper extremity emphasizing those that can be assessed using current clinical MR imaging protocols and addresses the limitations of current imaging techniques in evaluating the articular cartilage of smaller joints. It also provides a brief overview of novel techniques that may be instituted in the future to improve the diagnostic performance of MR imaging in the evaluation of the articular cartilage of the upper extremity.
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Affiliation(s)
- Humberto G Rosas
- Musculoskeletal Radiology, Department of Radiology, University of Wisconsin School of Medicine and Public Health, University of Wisconsin Hospital and Clinics, F2/422, 600 Highland Avenue, Madison, WI 53792, USA.
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Strickland CD, Kijowski R. Morphologic Imaging of Articular Cartilage. Magn Reson Imaging Clin N Am 2011; 19:229-48. [DOI: 10.1016/j.mric.2011.02.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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46
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Hu P, Stoeck CT, Smink J, Peters DC, Ngo L, Goddu B, Kissinger KV, Goepfert LA, Chan J, Hauser TH, Rofsky NM, Manning WJ, Nezafat R. Noncontrast SSFP pulmonary vein magnetic resonance angiography: impact of off-resonance and flow. J Magn Reson Imaging 2011; 32:1255-61. [PMID: 21031533 DOI: 10.1002/jmri.22356] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To investigate pulmonary vein (PV) off-resonance and blood flow as causes of signal void artifacts in noncontrast steady-state-free-precession (SSFP) PV magnetic resonance angiography (MRA). MATERIALS AND METHODS PV blood off-resonance was measured on 11 healthy adult subjects and 10 atrial fibrillation (AF) patients. Noncontrast PV MRA was performed using a 3D slab-selective SSFP sequence at 1.5T on seven healthy subjects with signal profile shifts of 0-125 Hz. The time-resolved blood flow velocity of the PVs was measured on five healthy subjects. The impact of flow was studied on six healthy subjects, on whom SSFP PV MRA was acquired twice with the electrocardiogram (ECG) trigger delay corresponding to low and high flow, respectively. RESULTS The PV off-resonances were 97 ± 27 Hz, 65 ± 20 Hz, 74 ± 25 Hz, and 52 ± 17 Hz for right inferior, left inferior, right superior, and left superior PVs, respectively, on healthy subjects, and 74 ± 20 Hz, 38 ± 9 Hz, 51 ± 20 Hz, and 28 ± 11 Hz on AF patients (P<0.01 for all). The off-resonance caused severe signal voids in the PVs. Signal acquired during mid-diastole with high PV flow caused additional signal voids in the left atrium, which was reduced by setting the ECG trigger delay to late-diastole. CONCLUSION PV off-resonance and flow causes signal void artifacts in noncontrast 3D slab-selective SSFP PV MRA.
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Affiliation(s)
- Peng Hu
- Department of Medicine (Cardiology Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA
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Bled E, Hassen WB, Pourtau L, Mellet P, Lanz T, Schüler D, Voisin P, Franconi JM, Thiaudière E, Miraux S. Real-time 3D MRI of contrast agents in whole living mice. CONTRAST MEDIA & MOLECULAR IMAGING 2011; 6:275-81. [PMID: 21287680 DOI: 10.1002/cmmi.429] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2010] [Revised: 10/26/2010] [Accepted: 10/27/2010] [Indexed: 01/31/2023]
Abstract
A specific mouse whole body coil and a dedicated gradient system at 4.7 T were coupled with an ultra-fast 3D gradient echo MRI and keyhole reconstruction technique to obtain 3D whole-body dynamic T(1)-weighted or T(2)*-weighted imaging. The technique was used to visualize the real-time distribution of non-targeting T(1) and T(2)* contrast agent (CA) in a glioma-bearing mouse model. T(1) dynamic contrast-enhancement imaging was performed with a fast imaging with steady-state precession sequence [echo time/repetition time (TE/TR), 1.32/3.7 ms] before and after CA injection (Gd-DOTA and BSA-Gd-DOTA) for 21 min. The temporal resolution was 1 image/6.5 s. T(2)* imaging (TE/TR, 4/8 ms) was performed before and after iron-based (small and ultra-small particles of iron oxide) CA injection for 45 min. The temporal resolution was 1 image/14 s. Signal-to-noise ratio curves were determined in various mouse organs. The whole-body coil and gradient systems made it possible to acquire data with sufficient and homogeneous signal-to-noise ratio on the whole animal. The spatial resolution allowed adequate depiction of the major organs, blood vessels and brain glioma. The distribution and the time-course of T(1) and T(2)* contrasts upon contrast agent injection were also assessed. 3D whole-body mouse MRI is feasible at high spatial resolution in movie mode and can be applied successfully to visualize real-time contrast agent distribution. This method should be effective in future preclinical molecular imaging studies.
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Affiliation(s)
- Emilie Bled
- Centre de Résonance Magnétique des Systèmes biologiques, UMR 5536, CNRS/Université Victor Segalen Bordeaux 2, 146, rue Léo Saignat 33076 Bordeaux Cedex, France
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48
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Miller KL, Tijssen RHN, Stikov N, Okell TW. Steady-state MRI: methods for neuroimaging. ACTA ACUST UNITED AC 2011. [DOI: 10.2217/iim.10.66] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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49
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Magnetic resonance imaging. Rheumatology (Oxford) 2011. [DOI: 10.1016/b978-0-323-06551-1.00039-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Abstract
Magnetic resonance (MR) imaging is one of the most commonly used imaging modality for evaluating patients with joint pain. Musculoskeletal MR protocols at most institutions consist of 2-dimensional fast spin echo (FSE) sequences repeated in multiple planes. Three-dimensional sequences have also been used to evaluate the musculoskeletal system and have many potential advantages over 2-dimensional FSE sequences. Three-dimensional sequences acquire thin continuous slices through joints with high in-plane spatial resolution, which minimize the effects of partial volume averaging. Newly developed 3-dimensional isotropic resolution sequences can also be used to create high-quality multiplanar reformat images that allow joints to be evaluated in any orientation after a single acquisition. Preliminary results on the use of 3-dimensional isotropic resolution sequences for evaluating the musculoskeletal system are encouraging. However, additional studies are needed to document the advantages of 3-dimensional sequences before they can replace currently used 2-dimensional FSE sequences for evaluating the musculoskeletal system in clinical practice.
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Affiliation(s)
- Richard Kijowski
- University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.
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