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Küstner T, Munoz C, Psenicny A, Bustin A, Fuin N, Qi H, Neji R, Kunze K, Hajhosseiny R, Prieto C, Botnar R. Deep-learning based super-resolution for 3D isotropic coronary MR angiography in less than a minute. Magn Reson Med 2021; 86:2837-2852. [PMID: 34240753 DOI: 10.1002/mrm.28911] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 06/08/2021] [Accepted: 06/11/2021] [Indexed: 01/21/2023]
Abstract
PURPOSE To develop and evaluate a novel and generalizable super-resolution (SR) deep-learning framework for motion-compensated isotropic 3D coronary MR angiography (CMRA), which allows free-breathing acquisitions in less than a minute. METHODS Undersampled motion-corrected reconstructions have enabled free-breathing isotropic 3D CMRA in ~5-10 min acquisition times. In this work, we propose a deep-learning-based SR framework, combined with non-rigid respiratory motion compensation, to shorten the acquisition time to less than 1 min. A generative adversarial network (GAN) is proposed consisting of two cascaded Enhanced Deep Residual Network generator, a trainable discriminator, and a perceptual loss network. A 16-fold increase in spatial resolution is achieved by reconstructing a high-resolution (HR) isotropic CMRA (0.9 mm3 or 1.2 mm3 ) from a low-resolution (LR) anisotropic CMRA (0.9 × 3.6 × 3.6 mm3 or 1.2 × 4.8 × 4.8 mm3 ). The impact and generalization of the proposed SRGAN approach to different input resolutions and operation on image and patch-level is investigated. SRGAN was evaluated on a retrospective downsampled cohort of 50 patients and on 16 prospective patients that were scanned with LR-CMRA in ~50 s under free-breathing. Vessel sharpness and length of the coronary arteries from the SR-CMRA is compared against the HR-CMRA. RESULTS SR-CMRA showed statistically significant (P < .001) improved vessel sharpness 34.1% ± 12.3% and length 41.5% ± 8.1% compared with LR-CMRA. Good generalization to input resolution and image/patch-level processing was found. SR-CMRA enabled recovery of coronary stenosis similar to HR-CMRA with comparable qualitative performance. CONCLUSION The proposed SR-CMRA provides a 16-fold increase in spatial resolution with comparable image quality to HR-CMRA while reducing the predictable scan time to <1 min.
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Affiliation(s)
- Thomas Küstner
- School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, United Kingdom
- Medical Image and Data Analysis, Department of Interventional and Diagnostic Radiology, University Hospital of Tübingen, Tübingen, Germany
| | - Camila Munoz
- School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, United Kingdom
| | - Alina Psenicny
- School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, United Kingdom
| | - Aurelien Bustin
- School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, United Kingdom
- Centre de recherche Cardio-Thoracique de Bordeaux, IHU LIRYC, Electrophysiology and Heart Modeling Institute, Université de Bordeaux, INSERM, Bordeaux, France
| | - Niccolo Fuin
- School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, United Kingdom
| | - Haikun Qi
- School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, United Kingdom
| | - Radhouene Neji
- School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, United Kingdom
- MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom
| | - Karl Kunze
- School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, United Kingdom
- MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom
| | - Reza Hajhosseiny
- School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, United Kingdom
| | - Claudia Prieto
- School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, United Kingdom
- Escuela de Ingeniería, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - René Botnar
- School of Biomedical Engineering and Imaging Sciences, King's College London, St. Thomas' Hospital, London, United Kingdom
- Escuela de Ingeniería, Pontificia Universidad Católica de Chile, Santiago, Chile
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A multi-scale variational neural network for accelerating motion-compensated whole-heart 3D coronary MR angiography. Magn Reson Imaging 2020; 70:155-167. [DOI: 10.1016/j.mri.2020.04.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 02/03/2020] [Accepted: 04/12/2020] [Indexed: 11/22/2022]
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Hosseini SAH, Zhang C, Weingärtner S, Moeller S, Stuber M, Ugurbil K, Akçakaya M. Accelerated coronary MRI with sRAKI: A database-free self-consistent neural network k-space reconstruction for arbitrary undersampling. PLoS One 2020; 15:e0229418. [PMID: 32084235 PMCID: PMC7034900 DOI: 10.1371/journal.pone.0229418] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 02/05/2020] [Indexed: 02/01/2023] Open
Abstract
Purpose To accelerate coronary MRI acquisitions with arbitrary undersampling patterns by using a novel reconstruction algorithm that applies coil self-consistency using subject-specific neural networks. Methods Self-consistent robust artificial-neural-networks for k-space interpolation (sRAKI) performs iterative parallel imaging reconstruction by enforcing self-consistency among coils. The approach bears similarity to SPIRiT, but extends the linear convolutions in SPIRiT to nonlinear interpolation using convolutional neural networks (CNNs). These CNNs are trained individually for each scan using the scan-specific autocalibrating signal (ACS) data. Reconstruction is performed by imposing the learned self-consistency and data-consistency, which enables sRAKI to support random undersampling patterns. Fully-sampled targeted right coronary artery MRI was acquired in six healthy subjects. The data were retrospectively undersampled, and reconstructed using SPIRiT, l1-SPIRiT and sRAKI for acceleration rates of 2 to 5. Additionally, prospectively undersampled whole-heart coronary MRI was acquired to further evaluate reconstruction performance. Results sRAKI reduces noise amplification and blurring artifacts compared with SPIRiT and l1-SPIRiT, especially at high acceleration rates in targeted coronary MRI. Quantitative analysis shows that sRAKI outperforms these techniques in terms of normalized mean-squared-error (~44% and ~21% over SPIRiT and l1-SPIRiT at rate 5) and vessel sharpness (~10% and ~20% over SPIRiT and l1-SPIRiT at rate 5). Whole-heart data shows the sharpest coronary arteries when resolved using sRAKI, with 11% and 15% improvement in vessel sharpness over SPIRiT and l1-SPIRiT, respectively. Conclusion sRAKI is a database-free neural network-based reconstruction technique that may further accelerate coronary MRI with arbitrary undersampling patterns, while improving noise resilience over linear parallel imaging and image sharpness over l1 regularization techniques.
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Affiliation(s)
- Seyed Amir Hossein Hosseini
- Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, United States of America
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States of America
| | - Chi Zhang
- Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, United States of America
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States of America
| | - Sebastian Weingärtner
- Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, United States of America
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States of America
- Department of Imaging Physics, Delft University of Technology, Delft, Netherlands
| | - Steen Moeller
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States of America
| | - Matthias Stuber
- Department of Radiology, University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland
- Center for Biomedical Imaging (CIBM), Lausanne, Switzerland
| | - Kamil Ugurbil
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States of America
| | - Mehmet Akçakaya
- Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, United States of America
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States of America
- * E-mail:
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Hossein Hosseini SA, Moeller S, Weingärtner S, Uǧurbil K, Akçakaya M. ACCELERATED CORONARY MRI USING 3D SPIRIT-RAKI WITH SPARSITY REGULARIZATION. PROCEEDINGS. IEEE INTERNATIONAL SYMPOSIUM ON BIOMEDICAL IMAGING 2019; 2019:1692-1695. [PMID: 31893013 DOI: 10.1109/isbi.2019.8759459] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Coronary MRI is a non-invasive radiation-free imaging tool for the diagnosis of coronary artery disease. One of its limitations is the long scan time, due to the need for high resolution imaging in the presence of respiratory and cardiac motions. Machine learning (ML) methods have been recently utilized to accelerate MRI. In particular, a scan-specific ML technique, called Robust Artifical-neural-network for k-space Interpolation (RAKI) has shown promise in cardiac MRI. However, it requires uniform undersampling. In this study, we sought to extend this approach to arbitrary sampling patterns, using coil self-consistency. This technique, called SPIRiT-RAKI, utilizes scan-specific convolutional neural networks to nonlinearly enforce coil self-consistency. Additionally, regularization terms can also be incorporated. SPIRiT-RAKI was used to accelerate right coronary MRI. Reconstructions were compared to SPIRiT for different undersampling patterns and acceleration rates. Results show SPIRiT-RAKI reduces residual aliasing and blurring artifacts compared to SPIRiT.
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Affiliation(s)
- Seyed Amir Hossein Hosseini
- Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, USA.,Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
| | - Steen Moeller
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
| | - Sebastian Weingärtner
- Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, USA.,Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
| | - Kȃmil Uǧurbil
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
| | - Mehmet Akçakaya
- Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, USA.,Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA
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Kamesh Iyer S, Moon B, Hwuang E, Han Y, Solomon M, Litt H, Witschey WR. Accelerated free-breathing 3D T1ρ cardiovascular magnetic resonance using multicoil compressed sensing. J Cardiovasc Magn Reson 2019; 21:5. [PMID: 30626437 PMCID: PMC6327532 DOI: 10.1186/s12968-018-0507-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 11/13/2018] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Endogenous contrast T1ρ cardiovascular magnetic resonance (CMR) can detect scar or infiltrative fibrosis in patients with ischemic or non-ischemic cardiomyopathy. Existing 2D T1ρ techniques have limited spatial coverage or require multiple breath-holds. The purpose of this project was to develop an accelerated, free-breathing 3D T1ρ mapping sequence with whole left ventricle coverage using a multicoil, compressed sensing (CS) reconstruction technique for rapid reconstruction of undersampled k-space data. METHODS We developed a cardiac- and respiratory-gated, free-breathing 3D T1ρ sequence and acquired data using a variable-density k-space sampling pattern (A = 3). The effect of the transient magnetization trajectory, incomplete recovery of magnetization between T1ρ-preparations (heart rate dependence), and k-space sampling pattern on T1ρ relaxation time error and edge blurring was analyzed using Bloch simulations for normal and chronically infarcted myocardium. Sequence accuracy and repeatability was evaluated using MnCl2 phantoms with different T1ρ relaxation times and compared to 2D measurements. We further assessed accuracy and repeatability in healthy subjects and compared these results to 2D breath-held measurements. RESULTS The error in T1ρ due to incomplete recovery of magnetization between T1ρ-preparations was T1ρhealthy = 6.1% and T1ρinfarct = 10.8% at 60 bpm and T1ρhealthy = 13.2% and T1ρinfarct = 19.6% at 90 bpm. At a heart rate of 60 bpm, error from the combined effects of readout-dependent magnetization transients, k-space undersampling and reordering was T1ρhealthy = 12.6% and T1ρinfarct = 5.8%. CS reconstructions had improved edge sharpness (blur metric = 0.15) compared to inverse Fourier transform reconstructions (blur metric = 0.48). There was strong agreement between the mean T1ρ estimated from the 2D and accelerated 3D data (R2 = 0.99; P < 0.05) acquired on the MnCl2 phantoms. The mean R1ρ estimated from the accelerated 3D sequence was highly correlated with MnCl2 concentration (R2 = 0.99; P < 0.05). 3D T1ρ acquisitions were successful in all human subjects. There was no significant bias between undersampled 3D T1ρ and breath-held 2D T1ρ (mean bias = 0.87) and the measurements had good repeatability (COV2D = 6.4% and COV3D = 7.1%). CONCLUSIONS This is the first report of an accelerated, free-breathing 3D T1ρ mapping of the left ventricle. This technique may improve non-contrast myocardial tissue characterization in patients with heart disease in a scan time appropriate for patients.
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Affiliation(s)
- Srikant Kamesh Iyer
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104 USA
| | - Brianna Moon
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104 USA
| | - Eileen Hwuang
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104 USA
| | - Yuchi Han
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104 USA
| | - Michael Solomon
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104 USA
| | - Harold Litt
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104 USA
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104 USA
| | - Walter R. Witschey
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104 USA
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Automated Curved and Multiplanar Reformation for Screening of the Proximal Coronary Arteries in MR Angiography. J Imaging 2018. [DOI: 10.3390/jimaging4110124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Congenital anomalies of the coronary ostia can lead to sudden death. A screening solution would be useful to prevent adverse outcomes for the affected individuals. To be considered for integration into clinical routine, such a procedure must meet strict constraints in terms of invasiveness, time and user interaction. Imaging must be fast and seamlessly integrable into the clinical process. Non-contrast enhanced coronary magnetic resonance angiography (MRA) is well suited for this. Furthermore, planar reformations proved effective to reduce the acquired volumetric datasets to 2D images. These usually require time consuming user interaction, though. To fulfill the aforementioned challenges, we present a fully automated solution for imaging and reformatting of the proximal coronary arteries which enables rapid screening of these. The proposed pipeline consists of: (I) highly accelerated single breath-hold MRA data acquisition, (II) coronary ostia detection and vessel centerline extraction, and (III) curved planar reformation of the proximal coronary arteries, as well as multiplanar reformation of the coronary ostia. The procedure proved robust and effective in ten volunteer data sets. Imaging of the proximal coronary arteries took 24 ± 5 s and was successful within one breath-hold for all patients. The extracted centerlines achieve an overlap of 0.76 ± 0.18 compared to the reference standard and the average distance of the centerline points from the spherical surface for reformation was 1.1 ± 0.51 mm. The promising results encourage further experiments on patient data, particularly in coronary ostia anomaly screening.
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7
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Bustin A, Ginami G, Cruz G, Correia T, Ismail TF, Rashid I, Neji R, Botnar RM, Prieto C. Five-minute whole-heart coronary MRA with sub-millimeter isotropic resolution, 100% respiratory scan efficiency, and 3D-PROST reconstruction. Magn Reson Med 2018; 81:102-115. [PMID: 30058252 PMCID: PMC6617822 DOI: 10.1002/mrm.27354] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 03/23/2018] [Accepted: 04/19/2018] [Indexed: 01/08/2023]
Abstract
Purpose To enable whole‐heart 3D coronary magnetic resonance angiography (CMRA) with isotropic sub‐millimeter resolution in a clinically feasible scan time by combining respiratory motion correction with highly accelerated variable density sampling in concert with a novel 3D patch‐based undersampled reconstruction (3D‐PROST). Methods An undersampled variable density spiral‐like Cartesian trajectory was combined with 2D image‐based navigators to achieve 100% respiratory efficiency and predictable scan time. 3D‐PROST reconstruction integrates structural information from 3D patch neighborhoods through sparse representation, thereby exploiting the redundancy of the 3D anatomy of the coronary arteries in an efficient low‐rank formulation. The proposed framework was evaluated in a static resolution phantom and in 10 healthy subjects with isotropic resolutions of 1.2 mm3 and 0.9 mm3 and undersampling factors of ×5 and ×9. 3D‐PROST was compared against fully sampled (1.2 mm3 only), conventional parallel imaging, and compressed sensing reconstructions. Results Phantom and in vivo (1.2 mm3) reconstructions were in excellent agreement with the reference fully sampled image. In vivo average acquisition times (min:s) were 7:57 ± 1:18 (×5) and 4:35 ± 0:44 (×9) for 0.9 mm3 resolution. Sub‐millimeter 3D‐PROST resulted in excellent depiction of the left and right coronary arteries including small branch vessels, leading to further improvements in vessel sharpness and visible vessel length in comparison with conventional reconstruction techniques. Image quality rated by 2 experts demonstrated that 3D‐PROST provides good image quality and is robust even at high acceleration factors. Conclusion The proposed approach enables free‐breathing whole‐heart 3D CMRA with isotropic sub‐millimeter resolution in <5 min and achieves improved coronary artery visualization in a short and predictable scan time.
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Affiliation(s)
- Aurélien Bustin
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Giulia Ginami
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Gastão Cruz
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Teresa Correia
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Tevfik F Ismail
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Imran Rashid
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Radhouene Neji
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom.,MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom
| | - René M Botnar
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom.,Escuela de Ingeniería, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Claudia Prieto
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom.,Escuela de Ingeniería, Pontificia Universidad Católica de Chile, Santiago, Chile
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Basha TA, Akçakaya M, Liew C, Tsao CW, Delling FN, Addae G, Ngo L, Manning WJ, Nezafat R. Clinical performance of high-resolution late gadolinium enhancement imaging with compressed sensing. J Magn Reson Imaging 2017; 46:1829-1838. [PMID: 28301075 DOI: 10.1002/jmri.25695] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 02/15/2017] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To evaluate diagnostic image quality of 3D late gadolinium enhancement (LGE) with high isotropic spatial resolution (∼1.4 mm3 ) images reconstructed from randomly undersampled k-space using LOw-dimensional-structure Self-learning and Thresholding (LOST). MATERIALS AND METHODS We prospectively enrolled 270 patients (181 men; 55 ± 14 years) referred for myocardial viability assessment. 3D LGE with isotropic spatial resolution of 1.4 ± 0.1 mm3 was acquired at 1.5T using a LOST acceleration rate of 3 to 5. In a subset of 121 patients, 3D LGE or phase-sensitive LGE were acquired with parallel imaging with an acceleration rate of 2 for comparison. Two readers evaluated image quality using a scale of 1 (poor) to 4 (excellent) and assessed for scar presence. The McNemar test statistic was used to compare the proportion of detected scar between the two sequences. We assessed the association between image quality and characteristics (age, gender, torso dimension, weight, heart rate), using generalized linear models. RESULTS Overall, LGE detection proportions for 3D LGE with LOST were similar between readers 1 and 2 (16.30% vs. 18.15%). For image quality, readers gave 85.9% and 80.0%, respectively, for images categorized as good or excellent. Overall proportion of scar presence was not statistically different from conventional 3D LGE (28% vs. 33% [P = 0.17] for reader 1 and 26% vs. 31% [P = 0.37] for reader 2). Increasing subject heart rate was associated with lower image quality (estimated slope = -0.009 (P = 0.001)). CONCLUSION High-resolution 3D LGE with LOST yields good to excellent image quality in >80% of patients and identifies patients with LV scar at the same rate as conventional 3D LGE. LEVEL OF EVIDENCE 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017;46:1829-1838.
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Affiliation(s)
- Tamer A Basha
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.,Systems and Biomedical Engineering Department, University of Cairo, Cairo, Egypt
| | - Mehmet Akçakaya
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota, USA.,Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota, USA
| | - Charlene Liew
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Connie W Tsao
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Francesca N Delling
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Gifty Addae
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Long Ngo
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Warren J Manning
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA.,Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Reza Nezafat
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
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Wang SC, Patel AR, Tanaka A, Wang H, Ota T, Lang RM, Carroll TJ, Kawaji K. A novel profile/view ordering with a non-convex star shutter for high-resolution 3D volumetric T 1 mapping under multiple breath-holds. Magn Reson Med 2016; 77:2215-2224. [PMID: 27404803 DOI: 10.1002/mrm.26303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 04/26/2016] [Accepted: 05/20/2016] [Indexed: 01/20/2023]
Abstract
PURPOSE To examine a novel non-convex star ordering/shutter for reducing the number of breath-holds in cardiac three-dimensional (3D) T1 Mapping MRI with multiple breath-holds. METHODS A novel ordering, Non-Convex Star (NCS) was designed to acquire 3D volumes in a modified look-locker inversion recovery (MOLLI) T1 mapping sequence to provide more spatial resolution and coverage in fewer breath-holds. The proposed 3D-MOLLI approach using NCS was first validated in two phantoms using artifact power (AP) measurement against the fully sampled phantom. This was followed by an in vivo study in seven swine, in which the T1 values of the left ventricular (LV) myocardium divided into the American Heart Association (AHA) 16-segment model was compared against the reference multislice two-dimensional (2D) clinical reference and 3D volume without NCS breath-hold reduction. RESULTS NCS breath-hold reduction yielded less AP compared with the matched SENSE accelerated phantom volume (P < 0.0005), and was shown to be optimal at 25% fewer breath-holds. Calculated T1 values from 3D in vivo volumes with/without NCS were comparable in all AHA segments (P = NS), whereas 3D-NCS yielded significantly higher T1 values than 2D at midslice of the LV myocardium in each AHA segment (P < 0.05). CONCLUSION We successfully demonstrate the feasibility of the NCS approach for a 3D T1 mapping acquisition requiring fewer breath-holds. Magn Reson Med 77:2215-2224, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Sui-Cheng Wang
- Department of Medicine, The University of Chicago, Chicago, Illinois, USA.,Biomedical Engineering, Northwestern University, Evanston, Illinois, USA
| | - Amit R Patel
- Department of Medicine, The University of Chicago, Chicago, Illinois, USA.,Radiology, The University of Chicago, Chicago, Illinois, USA
| | - Akiko Tanaka
- Surgery, The University of Chicago, Chicago, Illinois, USA
| | - Hui Wang
- Philips Healthcare, Cleveland, Ohio, USA
| | - Takeyoshi Ota
- Surgery, The University of Chicago, Chicago, Illinois, USA
| | - Roberto M Lang
- Department of Medicine, The University of Chicago, Chicago, Illinois, USA.,Radiology, The University of Chicago, Chicago, Illinois, USA
| | | | - Keigo Kawaji
- Department of Medicine, The University of Chicago, Chicago, Illinois, USA
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10
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Image reconstruction of compressed sensing MRI using graph-based redundant wavelet transform. Med Image Anal 2016; 27:93-104. [DOI: 10.1016/j.media.2015.05.012] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 05/10/2015] [Accepted: 05/22/2015] [Indexed: 11/24/2022]
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11
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Zhu Y, Guo Y, Lingala SG, Lebel RM, Law M, Nayak KS. GOCART: GOlden-angle CArtesian randomized time-resolved 3D MRI. Magn Reson Imaging 2015; 34:940-50. [PMID: 26707849 DOI: 10.1016/j.mri.2015.12.030] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 12/15/2015] [Accepted: 12/16/2015] [Indexed: 11/16/2022]
Abstract
PURPOSE To develop and evaluate a novel 3D Cartesian sampling scheme which is well suited for time-resolved 3D MRI using parallel imaging and compressed sensing. METHODS The proposed sampling scheme, termed GOlden-angle CArtesian Randomized Time-resolved (GOCART) 3D MRI, is based on golden angle (GA) Cartesian sampling, with random sampling of the ky-kz phase encode locations along each Cartesian radial spoke. This method was evaluated in conjunction with constrained reconstruction of retrospectively and prospectively undersampled in-vivo dynamic contrast enhanced (DCE) MRI data and simulated phantom data. RESULTS In in-vivo retrospective studies and phantom simulations, images reconstructed from phase encodes defined by GOCART were equal to or superior to those with Poisson disc or GA sampling schemes. Typical GOCART sampling tables were generated in <100ms. GOCART has also been successfully utilized prospectively to produce clinically valuable whole-brain DCE-MRI images. CONCLUSION GOCART is a practical and efficient sampling scheme for time-resolved 3D MRI. It shows great potential for highly accelerated DCE-MRI and is well suited to modern reconstruction methods such as parallel imaging and compressed sensing.
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Affiliation(s)
- Yinghua Zhu
- Ming Hsieh Department of Electrical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, USA.
| | - Yi Guo
- Ming Hsieh Department of Electrical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, USA
| | - Sajan Goud Lingala
- Ming Hsieh Department of Electrical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, USA
| | - R Marc Lebel
- Applied Science Laboratory, GE Healthcare, AB, Calgary, Canada; Foothills Medical Center, Calgary, Canada
| | - Meng Law
- Department of Radiology, Keck School of Medicine, University of Southern California Medical Center, Los Angeles, USA
| | - Krishna S Nayak
- Ming Hsieh Department of Electrical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, USA
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Luo J, Addy NO, Ingle RR, Hargreaves BA, Hu BS, Nishimura DG, Shin T. Combined outer volume suppression and T2 preparation sequence for coronary angiography. Magn Reson Med 2015; 74:1632-9. [PMID: 25521477 PMCID: PMC4470881 DOI: 10.1002/mrm.25575] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 11/10/2014] [Accepted: 11/14/2014] [Indexed: 12/25/2022]
Abstract
PURPOSE To develop a magnetization preparation sequence for simultaneous outer volume suppression (OVS) and T2 weighting in whole-heart coronary magnetic resonance angiography. METHODS A combined OVS and T2 preparation sequence (OVS-T2 Prep) was designed with a nonselective adiabatic 90° tipdown pulse, two adiabatic 180° refocusing pulses, and a 2D spiral -90° tipup pulse. The OVS-T2 Prep preserves the magnetization inside an elliptic cylinder with T2 weighting, while saturating the magnetization outside the cylinder. Its performance was tested on phantoms and on 13 normal subjects with coronary magnetic resonance angiography using 3D cones trajectories. RESULTS Phantom studies showed expected T2 -dependent signal amplitude in the spatial passband and suppressed signal in the spatial stopband. In vivo studies with full-field-of-view cones yielded a passband-to-stopband signal ratio of 3.18 ± 0.77 and blood-myocardium contrast-to-noise ratio enhancement by a factor of 1.43 ± 0.20 (P < 0.001). In vivo studies with reduced-field-of-view cones showed that OVS-T2 Prep well suppressed the aliasing artifacts, as supported by significantly reduced signal in the regions with no tissues compared to the images acquired without preparation (P < 0.0001). CONCLUSION OVS-T2 Prep is a compact sequence that can accelerate coronary magnetic resonance angiography by suppressing signals from tissues surrounding the heart while simultaneously enhancing the blood-myocardium contrast.
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Affiliation(s)
- Jieying Luo
- Department of Electrical Engineering, Magnetic Resonance Systems Research Laboratory, Stanford University, Stanford, California, USA
| | - Nii Okai Addy
- Department of Electrical Engineering, Magnetic Resonance Systems Research Laboratory, Stanford University, Stanford, California, USA
| | - R. Reeve Ingle
- Department of Electrical Engineering, Magnetic Resonance Systems Research Laboratory, Stanford University, Stanford, California, USA
| | | | - Bob S. Hu
- Department of Electrical Engineering, Magnetic Resonance Systems Research Laboratory, Stanford University, Stanford, California, USA
- Palo Alto Medical Foundation, Palo Alto, California, USA
| | - Dwight G. Nishimura
- Department of Electrical Engineering, Magnetic Resonance Systems Research Laboratory, Stanford University, Stanford, California, USA
| | - Taehoon Shin
- Diagnostic Radiology and Nuclear Medicine, University of Maryland, Baltimore, Maryland, USA
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Akçakaya M, Basha TA, Chan RH, Manning WJ, Nezafat R. Accelerated isotropic sub-millimeter whole-heart coronary MRI: compressed sensing versus parallel imaging. Magn Reson Med 2015; 71:815-22. [PMID: 23440946 DOI: 10.1002/mrm.24683] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
PURPOSE To enable accelerated isotropic sub-millimeter whole-heart coronary MRI within a 6-min acquisition and to compare this with a current state-of-the-art accelerated imaging technique at acceleration rates beyond what is used clinically. METHODS Coronary MRI still faces major challenges, including lengthy acquisition time, low signal-to-noise-ratio (SNR), and suboptimal spatial resolution. Higher spatial resolution in the sub-millimeter range is desirable, but this results in increased acquisition time and lower SNR, hindering its clinical implementation. In this study, we sought to use an advanced B1-weighted compressed sensing technique for highly accelerated sub-millimeter whole-heart coronary MRI, and to compare the results to parallel imaging, the current-state-of-the-art, where both techniques were used at acceleration rates beyond what is used clinically. Two whole-heart coronary MRI datasets were acquired in seven healthy adult subjects (30.3 ± 12.1 years; 3 men), using prospective 6-fold acceleration, with random undersampling for the proposed compressed sensing technique and with uniform undersampling for sensitivity encoding reconstruction. Reconstructed images were qualitatively compared in terms of image scores and perceived SNR on a four-point scale (1 = poor, 4 = excellent) by an experienced blinded reader. RESULTS The proposed technique resulted in images with clear visualization of all coronary branches. Overall image quality and perceived SNR of the compressed sensing images were significantly higher than those of parallel imaging (P = 0.03 for both), which suffered from noise amplification artifacts due to the reduced SNR. CONCLUSION The proposed compressed sensing-based reconstruction and acquisition technique for sub-millimeter whole-heart coronary MRI provides 6-fold acceleration, where it outperforms parallel imaging with uniform undersampling.
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Affiliation(s)
- Mehmet Akçakaya
- Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
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14
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Moghari MH, Annese D, Geva T, Powell AJ. Three-dimensional heart locator and compressed sensing for whole-heart MR angiography. Magn Reson Med 2015; 75:2086-93. [PMID: 26069182 DOI: 10.1002/mrm.25800] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 05/11/2015] [Accepted: 05/12/2015] [Indexed: 12/25/2022]
Abstract
PURPOSE We sought to develop a whole-heart magnetic resonance angiography technique with three-dimensional (3D) respiratory motion compensation and reduced scan time. METHODS A novel respiratory motion compensation method was implemented that acquires a 1D navigator (NAV) and a low-resolution 3D-image of the heart (3D-LOC) just before the angiography data. The central 10% of SSFP k-space was fully acquired using NAV-gating, and then 10% of peripheral k-space was randomly undersampled to complete the scan. Spatial registration of the 3D-LOC information was used to correct the central and peripheral k-space lines for the bulk respiratory motion in three dimensions, and then the remaining k-space data was estimated using compressed sensing (CS). Ten volunteers each underwent two angiography acquisitions with 1 mm(3) resolution: (i) conventional NAV with CS, and (ii) the new 3D-LOC with CS. RESULTS Compared with conventional NAV, the new 3D-LOC with CS technique had a shorter scan time (4.8 ± 1.1 versus 6.3 ± 1.7 min; P < 0.001), better objective vessel sharpness for all three coronary arteries (P < 0.05), and no difference in subjective vessel sharpness for all three coronary arteries. CONCLUSION Compared with conventional NAV with CS, acceleration and respiratory motion correction using 3D-LOC with CS reduces scan time and improves objective vessel sharpness.
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Affiliation(s)
- Mehdi H Moghari
- Department of Cardiology, Boston Children's Hospital, Boston, Massachusetts, USA.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - David Annese
- Department of Cardiology, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Tal Geva
- Department of Cardiology, Boston Children's Hospital, Boston, Massachusetts, USA.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Andrew J Powell
- Department of Cardiology, Boston Children's Hospital, Boston, Massachusetts, USA.,Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
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Basha TA, Akçakaya M, Goddu B, Berg S, Nezafat R. Accelerated three-dimensional cine phase contrast imaging using randomly undersampled echo planar imaging with compressed sensing reconstruction. NMR IN BIOMEDICINE 2015; 28:30-39. [PMID: 25323208 DOI: 10.1002/nbm.3225] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 09/04/2014] [Accepted: 09/10/2014] [Indexed: 06/04/2023]
Abstract
The aim of this study was to implement and evaluate an accelerated three-dimensional (3D) cine phase contrast MRI sequence by combining a randomly sampled 3D k-space acquisition sequence with an echo planar imaging (EPI) readout. An accelerated 3D cine phase contrast MRI sequence was implemented by combining EPI readout with randomly undersampled 3D k-space data suitable for compressed sensing (CS) reconstruction. The undersampled data were then reconstructed using low-dimensional structural self-learning and thresholding (LOST). 3D phase contrast MRI was acquired in 11 healthy adults using an overall acceleration of 7 (EPI factor of 3 and CS rate of 3). For comparison, a single two-dimensional (2D) cine phase contrast scan was also performed with sensitivity encoding (SENSE) rate 2 and approximately at the level of the pulmonary artery bifurcation. The stroke volume and mean velocity in both the ascending and descending aorta were measured and compared between two sequences using Bland-Altman plots. An average scan time of 3 min and 30 s, corresponding to an acceleration rate of 7, was achieved for 3D cine phase contrast scan with one direction flow encoding, voxel size of 2 × 2 × 3 mm(3) , foot-head coverage of 6 cm and temporal resolution of 30 ms. The mean velocity and stroke volume in both the ascending and descending aorta were statistically equivalent between the proposed 3D sequence and the standard 2D cine phase contrast sequence. The combination of EPI with a randomly undersampled 3D k-space sampling sequence using LOST reconstruction allows a seven-fold reduction in scan time of 3D cine phase contrast MRI without compromising blood flow quantification.
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Affiliation(s)
- Tamer A Basha
- Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
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16
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Roujol S, Foppa M, Basha TA, Akçakaya M, Kissinger KV, Goddu B, Berg S, Nezafat R. Accelerated free breathing ECG triggered contrast enhanced pulmonary vein magnetic resonance angiography using compressed sensing. J Cardiovasc Magn Reson 2014; 16:91. [PMID: 25416082 PMCID: PMC4240816 DOI: 10.1186/s12968-014-0091-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 11/04/2014] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND To investigate the feasibility of accelerated electrocardiogram (ECG)-triggered contrast enhanced pulmonary vein magnetic resonance angiography (CE-PV MRA) with isotropic spatial resolution using compressed sensing (CS). METHODS Nineteen patients (59±13 y, 11 M) referred for MR were scanned using the proposed accelerated free breathing ECG-triggered 3D CE-PV MRA sequence (FOV=340×340×110 mm3, spatial resolution=1.5×1.5×1.5 mm3, acquisition window=140 ms at mid diastole and CS acceleration factor=5) and a conventional first-pass breath-hold non ECG-triggered 3D CE-PV MRA sequence. CS data were reconstructed offline using low-dimensional-structure self-learning and thresholding reconstruction (LOST) CS reconstruction. Quantitative analysis of PV sharpness and subjective qualitative analysis of overall image quality were performed using a 4-point scale (1: poor; 4: excellent). RESULTS Quantitative PV sharpness was increased using the proposed approach (0.73±0.09 vs. 0.51±0.07 for the conventional CE-PV MRA protocol, p<0.001). There were no significant differences in the subjective image quality scores between the techniques (3.32±0.94 vs. 3.53±0.77 using the proposed technique). CONCLUSIONS CS-accelerated free-breathing ECG-triggered CE-PV MRA allows evaluation of PV anatomy with improved sharpness compared to conventional non-ECG gated first-pass CE-PV MRA. This technique may be a valuable alternative for patients in which the first pass CE-PV MRA fails due to inaccurate first pass timing or inability of the patient to perform a 20-25 seconds breath-hold.
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Affiliation(s)
- Sébastien Roujol
- Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Ave, Boston, MA 02215 USA
| | - Murilo Foppa
- Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Ave, Boston, MA 02215 USA
| | - Tamer A Basha
- Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Ave, Boston, MA 02215 USA
| | - Mehmet Akçakaya
- Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Ave, Boston, MA 02215 USA
| | - Kraig V Kissinger
- Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Ave, Boston, MA 02215 USA
| | - Beth Goddu
- Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Ave, Boston, MA 02215 USA
| | - Sophie Berg
- Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Ave, Boston, MA 02215 USA
| | - Reza Nezafat
- Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Ave, Boston, MA 02215 USA
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Weingärtner S, Akçakaya M, Roujol S, Basha T, Tschabrunn C, Berg S, Anter E, Nezafat R. Free-breathing combined three-dimensional phase sensitive late gadolinium enhancement and T1 mapping for myocardial tissue characterization. Magn Reson Med 2014; 74:1032-41. [PMID: 25324205 DOI: 10.1002/mrm.25495] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 08/29/2014] [Accepted: 09/20/2014] [Indexed: 01/05/2023]
Abstract
PURPOSE To develop a novel MR sequence for combined three-dimensional (3D) phase-sensitive (PS) late gadolinium enhancement (LGE) and T1 mapping to allow for simultaneous assessment of focal and diffuse myocardial fibrosis. METHODS In the proposed sequence, four 3D imaging volumes are acquired with different T1 weightings using a combined saturation and inversion preparation, after administration of a gadolinium contrast agent. One image is acquired fully sampled with the inversion time selected to null the healthy myocardial signal (the LGE image). The other three images are three-fold under-sampled and reconstructed using compressed sensing. An acquisition scheme with two interleaved imaging cycles and joint navigator-gating of those cycles ensures spatial registration of the imaging volumes. T1 maps are generated using all four imaging volumes. The signal-polarity in the LGE image is restored using supplementary information from the T1 fit to generate PS-LGE images. The accuracy of the proposed method was assessed with respect to a inversion-recovery spin-echo sequence. In vivo T1 maps and LGE images were acquired with the proposed sequence and quantitatively compared with 2D multislice Modified Look-Locker inversion recovery (MOLLI) T1 maps. Exemplary images in a patient with focal scar were compared with conventional LGE imaging. RESULTS The deviation of the proposed method and the spin-echo reference was < 11 ms in phantom for T1 times between 250 and 600 ms, regardless of the inversion time selected in the LGE image. There was no significant difference in the in vivo T1 times of the proposed sequence and the 2D MOLLI technique (myocardium: 292 ± 75 ms versus 310 ± 49 ms, blood-pools: 191 ± 75 ms versus 182.0 ± 33). The LGE images showed proper nulling of the healthy myocardium in all subjects and clear depiction of scar in the patient. CONCLUSION The proposed sequence enables simultaneous acquisition of 3D PS-LGE images and spatially registered 3D T1 maps in a single scan.
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Affiliation(s)
- Sebastian Weingärtner
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
- Computer Assisted Clinical Medicine, University Medical Center Mannheim, Heidelberg University, Mannheim, Germany
| | - Mehmet Akçakaya
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Sébastien Roujol
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Tamer Basha
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Cory Tschabrunn
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Sophie Berg
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Elad Anter
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Reza Nezafat
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
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18
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Chen X, Salerno M, Yang Y, Epstein FH. Motion-compensated compressed sensing for dynamic contrast-enhanced MRI using regional spatiotemporal sparsity and region tracking: block low-rank sparsity with motion-guidance (BLOSM). Magn Reson Med 2014; 72:1028-38. [PMID: 24243528 PMCID: PMC4097987 DOI: 10.1002/mrm.25018] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 09/11/2013] [Accepted: 10/08/2013] [Indexed: 11/12/2022]
Abstract
PURPOSE Dynamic contrast-enhanced MRI of the heart is well-suited for acceleration with compressed sensing (CS) due to its spatiotemporal sparsity; however, respiratory motion can degrade sparsity and lead to image artifacts. We sought to develop a motion-compensated CS method for this application. METHODS A new method, Block LOw-rank Sparsity with Motion-guidance (BLOSM), was developed to accelerate first-pass cardiac MRI, even in the presence of respiratory motion. This method divides the images into regions, tracks the regions through time, and applies matrix low-rank sparsity to the tracked regions. BLOSM was evaluated using computer simulations and first-pass cardiac datasets from human subjects. Using rate-4 undersampling, BLOSM was compared with other CS methods such as k-t SLR that uses matrix low-rank sparsity applied to the whole image dataset, with and without motion tracking, and to k-t FOCUSS with motion estimation and compensation that uses spatial and temporal-frequency sparsity. RESULTS BLOSM was qualitatively shown to reduce respiratory artifact compared with other methods. Quantitatively, using root mean squared error and the structural similarity index, BLOSM was superior to other methods. CONCLUSION BLOSM, which exploits regional low-rank structure and uses region tracking for motion compensation, provides improved image quality for CS-accelerated first-pass cardiac MRI.
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Affiliation(s)
- Xiao Chen
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia
| | - Michael Salerno
- Department of Radiology, University of Virginia, Charlottesville, Virginia
- Department of Cardiology, University of Virginia, Charlottesville, Virginia
| | - Yang Yang
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia
| | - Frederick H. Epstein
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia
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Forman C, Piccini D, Grimm R, Hutter J, Hornegger J, Zenge MO. Reduction of respiratory motion artifacts for free-breathing whole-heart coronary MRA by weighted iterative reconstruction. Magn Reson Med 2014; 73:1885-95. [PMID: 24912763 DOI: 10.1002/mrm.25321] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Revised: 05/20/2014] [Accepted: 05/26/2014] [Indexed: 01/18/2023]
Abstract
PURPOSE To combine weighted iterative reconstruction with self-navigated free-breathing coronary magnetic resonance angiography for retrospective reduction of respiratory motion artifacts. METHODS One-dimensional self-navigation was improved for robust respiratory motion detection and the consistency of the acquired data was estimated on the detected motion. Based on the data consistency, the data fidelity term of iterative reconstruction was weighted to reduce the effects of respiratory motion. In vivo experiments were performed in 14 healthy volunteers and the resulting image quality of the proposed method was compared to a navigator-gated reference in terms of acquisition time, vessel length, and sharpness. RESULT Although the sampling pattern of the proposed method contained 60% more samples with respect to the reference, the scan efficiency was improved from 39.5 ± 10.1% to 55.1 ± 9.1%. The improved self-navigation showed a high correlation to the standard navigator signal and the described weighting efficiently reduced respiratory motion artifacts. Overall, the average image quality of the proposed method was comparable to the navigator-gated reference. CONCLUSION Self-navigated coronary magnetic resonance angiography was successfully combined with weighted iterative reconstruction to reduce the total acquisition time and efficiently suppress respiratory motion artifacts. The simplicity of the experimental setup and the promising image quality are encouraging toward future clinical evaluation.
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Affiliation(s)
- Christoph Forman
- Pattern Recognition Lab, Department of Computer Science, Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, Germany; Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, Germany
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20
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High-resolution 3D whole-heart coronary MRA: a study on the combination of data acquisition in multiple breath-holds and 1D residual respiratory motion compensation. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2014; 27:435-43. [PMID: 24402560 DOI: 10.1007/s10334-013-0428-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 12/09/2013] [Accepted: 12/16/2013] [Indexed: 10/25/2022]
Abstract
OBJECT To study a scan protocol for coronary magnetic resonance angiography based on multiple breath-holds featuring 1D motion compensation and to compare the resulting image quality to a navigator-gated free-breathing acquisition. Image reconstruction was performed using L1 regularized iterative SENSE. MATERIALS AND METHODS The effects of respiratory motion on the Cartesian sampling scheme were minimized by performing data acquisition in multiple breath-holds. During the scan, repetitive readouts through a k-space center were used to detect and correct the respiratory displacement of the heart by exploiting the self-navigation principle in image reconstruction. In vivo experiments were performed in nine healthy volunteers and the resulting image quality was compared to a navigator-gated reference in terms of vessel length and sharpness. RESULTS Acquisition in breath-hold is an effective method to reduce the scan time by more than 30% compared to the navigator-gated reference. Although an equivalent mean image quality with respect to the reference was achieved with the proposed method, the 1D motion compensation did not work equally well in all cases. CONCLUSION In general, the image quality scaled with the robustness of the motion compensation. Nevertheless, the featured setup provides a positive basis for future extension with more advanced motion compensation methods.
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21
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Akçakaya M, Basha TA, Pflugi S, Foppa M, Kissinger KV, Hauser TH, Nezafat R. Localized spatio-temporal constraints for accelerated CMR perfusion. Magn Reson Med 2013; 72:629-39. [PMID: 24123058 DOI: 10.1002/mrm.24963] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 08/12/2013] [Accepted: 09/03/2013] [Indexed: 01/09/2023]
Abstract
PURPOSE To develop and evaluate an image reconstruction technique for cardiac MRI (CMR) perfusion that uses localized spatio-temporal constraints. METHODS CMR perfusion plays an important role in detecting myocardial ischemia in patients with coronary artery disease. Breath-hold k-t-based image acceleration techniques are typically used in CMR perfusion for superior spatial/temporal resolution and improved coverage. In this study, we propose a novel compressed sensing-based image reconstruction technique for CMR perfusion, with applicability to free-breathing examinations. This technique uses local spatio-temporal constraints by regularizing image patches across a small number of dynamics. The technique was compared with conventional dynamic-by-dynamic reconstruction, and sparsity regularization using a temporal principal-component (pc) basis, as well as zero-filled data in multislice two-dimensional (2D) and three-dimensional (3D) CMR perfusion. Qualitative image scores were used (1 = poor, 4 = excellent) to evaluate the technique in 3D perfusion in 10 patients and five healthy subjects. On four healthy subjects, the proposed technique was also compared with a breath-hold multislice 2D acquisition with parallel imaging in terms of signal intensity curves. RESULTS The proposed technique produced images that were superior in terms of spatial and temporal blurring compared with the other techniques, even in free-breathing datasets. The image scores indicated a significant improvement compared with other techniques in 3D perfusion (x-pc regularization, 2.8 ± 0.5 versus 2.3 ± 0.5; dynamic-by-dynamic, 1.7 ± 0.5; zero-filled, 1.1 ± 0.2). Signal intensity curves indicate similar dynamics of uptake between the proposed method with 3D acquisition and the breath-hold multislice 2D acquisition with parallel imaging. CONCLUSION The proposed reconstruction uses sparsity regularization based on localized information in both spatial and temporal domains for highly accelerated CMR perfusion with potential use in free-breathing 3D acquisitions.
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Affiliation(s)
- Mehmet Akçakaya
- Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
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22
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Akçakaya M, Shaw JL, Hauser TH, Nezafat R. Utility of respiratory-navigator-rejected k-space lines for improved signal-to-noise ratio in three-dimensional cardiac MR. Magn Reson Med 2012; 70:1332-9. [PMID: 23233381 DOI: 10.1002/mrm.24566] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 10/20/2012] [Accepted: 10/26/2012] [Indexed: 01/17/2023]
Abstract
PURPOSE To develop and evaluate a technique that uses the k-space lines rejected by prospective respiratory navigator (NAV) to improve the signal-to-noise ratio (SNR) without increasing the scan time. METHODS In conventional image reconstruction, the motion-corrupted k-space lines rejected by the NAV are not used. In this study, a set of translational motion parameters for the NAV-rejected lines and a phase-corrected average for the k-space line are estimated jointly using a maximum-likelihood approach and the information from the corresponding accepted k-space lines. Left coronary artery images were acquired in 10 healthy adult subjects, and the proposed approach incorporating the NAV-rejected lines was compared with the conventional dataset with NAV-accepted lines only, as well as a simple average of all k-space lines, in terms of SNR, normalized vessel sharpness and qualitative image scores on a four-point scale (1 = poor, 4 = excellent). Late gadolinium enhancement images of the left atrium were also acquired in 21 patients with atrial fibrillation pre- or post-pulmonary vein isolation. Images reconstructed with the proposed, conventional, and simple averaging methods were compared in terms of SNR, and subjective image quality on a four-point scale. RESULTS For coronary MRI, there was a significant improvement in SNR with the proposed technique, but no significant difference in normalized vessel sharpness or qualitative image scores were observed with respect to the conventional method. Simple averaging resulted in an SNR gain, but significant loss in vessel sharpness and image quality. For late gadolinium enhancement, there was a significant increase in SNR, but no significant differences were observed in subjective image quality scores between the proposed and conventional methods. There was an SNR gain, but image quality loss for simple averaging, when compared with the conventional technique. In both coronary MRI and late gadolinium enhancement, the SNR gain of the proposed method was not significantly different than the maximum theoretical SNR gain. CONCLUSION The proposed technique improves SNR using the additional information from NAV-rejected k-space lines, while providing similar image quality to standard reconstruction using motion-free k-space data only, with no increase in scan time.
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Affiliation(s)
- Mehmet Akçakaya
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
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Kwak Y, Nam S, Akçakaya M, Basha TA, Goddu B, Manning WJ, Tarokh V, Nezafat R. Accelerated aortic flow assessment with compressed sensing with and without use of the sparsity of the complex difference image. Magn Reson Med 2012; 70:851-8. [PMID: 23065722 DOI: 10.1002/mrm.24514] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Revised: 09/04/2012] [Accepted: 09/11/2012] [Indexed: 12/22/2022]
Abstract
Phase contrast (PC) cardiac MR is widely used for the clinical assessment of blood flow in cardiovascular disease. One of the challenges of PC cardiac MR is the long scan time which limits both spatial and temporal resolution. Compressed sensing reconstruction with accelerated PC acquisitions is a promising technique to increase the scan efficiency. In this study, we sought to use the sparsity of the complex difference of the two flow-encoded images as an additional constraint term to improve the compressed sensing reconstruction of the corresponding accelerated PC data acquisition. Using retrospectively under-sampled data, the proposed reconstruction technique was optimized and validated in vivo on 15 healthy subjects. Then, prospectively under-sampled data was acquired on 11 healthy subjects and reconstructed with the proposed technique. The results show that there is good agreement between the cardiac output measurements from the fully sampled data and the proposed compressed sensing reconstruction method using complex difference sparsity up to acceleration rate 5. In conclusion, we have developed and evaluated an improved reconstruction technique for accelerated PC cardiac MR that uses the sparsity of the complex difference of the two flow-encoded images.
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Affiliation(s)
- Yongjun Kwak
- Department of Medicine (Cardiovascular Division), Harvard Medical School and Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA; School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts, USA
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Akçakaya M, Rayatzadeh H, Basha TA, Hong SN, Chan RH, Kissinger KV, Hauser TH, Josephson ME, Manning WJ, Nezafat R. Accelerated late gadolinium enhancement cardiac MR imaging with isotropic spatial resolution using compressed sensing: initial experience. Radiology 2012; 264:691-9. [PMID: 22820734 DOI: 10.1148/radiol.12112489] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PURPOSE To evaluate the use of low-dimensional-structure self-learning and thresholding (LOST) compressed sensing acquisition and reconstruction in the assessment of left atrial (LA) and left ventricular (LV) scar by using late gadolinium enhancement (LGE) magnetic resonance (MR) imaging with isotropic spatial resolution. MATERIALS AND METHODS The study was approved by the local institutional review board and was compliant with HIPAA. All subjects provided written informed consent. Twenty-eight patients (eight women; mean age, 58.0 years ± 10.1) with a history of atrial fibrillation were recruited for the LA LGE study, and 14 patients (five women; mean age, 54.2 years ± 18.6) were recruited for assessment of LV myocardial infarction. With use of a pseudorandom k-space undersampling pattern, threefold accelerated three-dimensional (3D) LGE data were acquired with isotropic spatial resolution and reconstructed off-line by using LOST. For comparison, subjects were also imaged by using standard 3D LGE protocols with nonisotropic spatial resolution. Images were compared qualitatively by three cardiologists with regard to diagnostic value, presence of enhancement, and image quality. The signed rank test and Wilcoxon unpaired two-sample test were used to test the hypothesis that there would be no significant difference in image quality ratings with different resolutions. RESULTS Interpretable images were obtained in 26 of the 28 patients (93%) in the LA LGE study. LGE was seen in 17 of 30 cases (57%) with nonisotropic resolution and in 18 cases (60%) with isotropic resolution. Diagnostic quality scores of isotropic images were significantly higher than those of nonisotropic images with coronal views (median, 3 vs 2, respectively [25th and 75th percentiles: 3, 3 vs 2, 3]; P < .001) and sagittal views (median, 3 vs 2 [25th and 75th percentiles: 3, 4 vs 2, 3]; P < .001) but lower with axial views (median, 4 vs 3 [25th and 75th percentiles: 3, 4 vs 3, 3]; P < .001). For the LV LGE study, all patients had interpretable images. LGE was seen in six of 14 patients (43%), with 100% agreement between both data sets. Diagnostic quality scores of high-isotropic-resolution LV images were higher than those of nonisotropic images with short-axis views (median, 4 vs 3 [25th and 75th percentiles: 3, 4 vs 2, 3]; P = .014) and two-chamber views (median, 4 vs 3 [25th and 75th percentiles: 3, 4 vs 2, 3]; P = .001). CONCLUSION An accelerated LGE acquisition with LOST enables imaging with high isotropic spatial resolution for improved assessment of LV, LA, and pulmonary vein scar.
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Affiliation(s)
- Mehmet Akçakaya
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Ave, Boston, MA 02215, USA
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