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Shi C, Liang D, Wang H, Zhu Y. High efficiency free-breathing 3D thoracic aorta vessel wall imaging using self-gating image reconstruction. Magn Reson Imaging 2024; 107:80-87. [PMID: 38237694 DOI: 10.1016/j.mri.2024.01.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 01/14/2024] [Indexed: 01/23/2024]
Abstract
PURPOSE To improve the scan efficiency of thoracic aorta vessel wall imaging using a self-gating (SG)-based motion correction scheme. MATERIALS AND METHODS A slab-selective variable-flip-angle 3D turbo spin-echo (SPACE) sequence was modified to acquire SG signals and imaging data. Cartesian sampling with a tiny golden-step spiral profile ordering was used to obtain the imaging data during the systolic period, and then the image data were subsequently corrected based on the SG signals and binned to different respiratory cycles. Finally, respiratory artifacts were estimated from image-based registration of 3D undersampled respiratory bins that were reconstructed with L1 iterative self-consistent parallel imaging reconstruction (SPIRiT). This method was evaluated in 11 healthy volunteers and compared against conventional diaphragmatic navigator-gated acquisition to assess the feasibility of the proposed framework. RESULTS Results showed that the proposed method achieved image quality comparable to that of conventional diaphragmatic navigator-gated acquisition with an average scan time of 4 min. The sharpness of the vessel wall and the definition of the liver boundary were in good agreement with the navigator-gated acquisition, which took approximately above 8.5 min depend on the respiratory rate. Further valuation of this technique in patients will be conducted to determine its clinical use.
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Affiliation(s)
- Caiyun Shi
- School of Biomedical Engineering, The Fourth Affiliated Hospital, Guangzhou Medical University, Guangzhou, China.
| | - Dong Liang
- Paul C. Lauterbur Research Centre for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Science, Shenzhen, Guangdong, China; Medical AI Research Centre, Shenzhen Institutes of Advanced Technology, Chinese Academy of Science, Shenzhen, Guangdong, China
| | - Haifeng Wang
- Paul C. Lauterbur Research Centre for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Science, Shenzhen, Guangdong, China
| | - Yanjie Zhu
- Paul C. Lauterbur Research Centre for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Science, Shenzhen, Guangdong, China.
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2
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Moussavi A, Boretius S. Imperfect magnetic field gradients in radial k-space encoding-Quantification, correction, and parameter dependency. Magn Reson Med 2018; 81:962-975. [PMID: 30260028 DOI: 10.1002/mrm.27449] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 06/12/2018] [Accepted: 06/16/2018] [Indexed: 02/04/2023]
Abstract
PURPOSE Sensitivity to imperfections of image-encoding gradient fields may significantly impair widespread use of radial MR data acquisition. Such imperfections can cause individual echo shifts for each spoke acquired in the k-space and may produce severe image artifacts. Therefore, fast and robust methods to quantify and correct for those echo shifts are required. THEORY AND METHODS Echo shifts can be induced by inhomogeneities of the static magnetic field (δnB ) and by imbalances of the imaging gradients (δnG ) mainly caused by eddy currents. However, mismatch between data acquisition and gradient switching may additionally play a role. From the position of the echo maxima of 2 opposing spokes, δnG and δnB can be determined and corrected by adapting the read-dephasing gradient accordantly. This approach was implemented on MR-systems of different field strengths, gradient systems, and vendors, and the dependencies of echo shift and acquisition parameters were analyzed. Data sets of phantoms and of mice under in vivo conditions were obtained using RF-spoiled 2D radial-FLASH. RESULTS The presented method allowed for echo-shift detection and correction of < 1 data point, significantly improving the image quality in vitro and in vivo. Moreover, the method separated the effect of imbalanced gradients from those of magnetic inhomogeneities. The observed echo shifts were MR system-specifically dependent on acquisition parameters such as gradient strengths and dwell time. CONCLUSIONS By acquiring 12 spokes for a certain set of acquisition parameters, the proposed method successfully corrects echo shift-related image artifacts independently of the MR system.
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Affiliation(s)
- Amir Moussavi
- Functional Imaging Laboratory, German Primate Center, Leibniz Institute for Primate Research, Göttingen, Germany.,Section Biomedical Imaging, Department of Radiology and Neuroradiology, Christian-Albrechts-University, Kiel, Germany
| | - Susann Boretius
- Functional Imaging Laboratory, German Primate Center, Leibniz Institute for Primate Research, Göttingen, Germany.,Section Biomedical Imaging, Department of Radiology and Neuroradiology, Christian-Albrechts-University, Kiel, Germany
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3
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Kim SE, Roberts JA, Eisenmenger LB, Aldred BW, Jamil O, Bolster BD, Bi X, Parker DL, Treiman GS, McNally JS. Motion-insensitive carotid intraplaque hemorrhage imaging using 3D inversion recovery preparation stack of stars (IR-prep SOS) technique. J Magn Reson Imaging 2016; 45:410-417. [PMID: 27383756 DOI: 10.1002/jmri.25365] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 06/15/2016] [Indexed: 11/11/2022] Open
Abstract
PURPOSE Carotid artery imaging is important in the clinical management of patients at risk for stroke. Carotid intraplaque hemorrhage (IPH) presents an important diagnostic challenge. 3D magnetization prepared rapid acquisition gradient echo (MPRAGE) has been shown to accurately image carotid IPH; however, this sequence can be limited due to motion- and flow-related artifact. The purpose of this work was to develop and evaluate an improved 3D carotid MPRAGE sequence for IPH detection. We hypothesized that a radial-based k-space trajectory sequence such as "Stack of Stars" (SOS) incorporated with inversion recovery preparation would offer reduced motion sensitivity and more robust flow suppression by oversampling of central k-space. MATERIALS AND METHODS A total of 31 patients with carotid disease (62 carotid arteries) were imaged at 3T magnetic resonance imaging (MRI) with 3D IR-prep Cartesian and SOS sequences. Image quality was determined between SOS and Cartesian MPRAGE in 62 carotid arteries using t-tests and multivariable linear regression. Kappa analysis was used to determine interrater reliability. RESULTS In all, 25 among 62 carotid plaques had carotid IPH by consensus from the reviewers on SOS compared to 24 on Cartesian sequence. Image quality was significantly higher with SOS compared to Cartesian (mean 3.74 vs. 3.11, P < 0.001). SOS acquisition yielded sharper image features with less motion (19.4% vs. 45.2%, P < 0.002) and flow artifact (27.4% vs. 41.9%, P < 0.089). There was also excellent interrater reliability with SOS (kappa = 0.89), higher than that of Cartesian (kappa = 0.84). CONCLUSION By minimizing flow and motion artifacts and retaining high interrater reliability, the SOS MPRAGE has important advantages over Cartesian MPRAGE in carotid IPH detection. LEVEL OF EVIDENCE 1 J. Magn. Reson. Imaging 2017;45:410-417.
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Affiliation(s)
- Seong-Eun Kim
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA.,Department of Radiology, University of Utah, Salt Lake City, Utah, USA
| | - John A Roberts
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA.,Department of Radiology, University of Utah, Salt Lake City, Utah, USA
| | | | - Booth W Aldred
- Department of Radiology, University of Utah, Salt Lake City, Utah, USA
| | - Osama Jamil
- Department of Radiology, University of Utah, Salt Lake City, Utah, USA
| | | | - Xiaoming Bi
- Siemens Healthcare, Salt Lake City, Utah, USA
| | - Dennis L Parker
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA.,Department of Radiology, University of Utah, Salt Lake City, Utah, USA
| | - Gerald S Treiman
- Department of Surgery, University of Utah, Salt Lake City, Utah, USA.,Department of Veterans Affairs, VASLCHCS, Salt Lake City, Utah, USA
| | - J Scott McNally
- Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah, USA.,Department of Radiology, University of Utah, Salt Lake City, Utah, USA
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4
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Magnetic resonance angiography of fetal vasculature at 3.0 T. Eur Radiol 2016; 26:4570-4576. [PMID: 27189488 DOI: 10.1007/s00330-016-4243-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 12/25/2015] [Accepted: 01/22/2016] [Indexed: 10/21/2022]
Abstract
Magnetic resonance angiography has not been used much previously for visualizing fetal vessels in utero for reasons that include a contraindication for the use of exogenous contrast agents, maternal respiratory motion and fetal motion. In this work, we report the feasibility of using an appropriately modified clinical time-of-flight magnetic resonance imaging sequence for non-contrast angiography of human fetal and placental vessels at 3.0 T. Using this 2D angiography technique, it is possible to visualize fetal vascular networks in late pregnancy. KEY POINTS • 3D-visualization of fetal vasculature is feasible using non-contrast MRA at 3.0 T. • Visualization of placental vasculature is also possible with this method. • Fetal MRA can serve as a vascular localizer for quantitative MRI studies. • This method can be extended to 1.5 T.
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Godenschweger F, Kägebein U, Stucht D, Yarach U, Sciarra A, Yakupov R, Lüsebrink F, Schulze P, Speck O. Motion correction in MRI of the brain. Phys Med Biol 2016; 61:R32-56. [PMID: 26864183 DOI: 10.1088/0031-9155/61/5/r32] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Subject motion in MRI is a relevant problem in the daily clinical routine as well as in scientific studies. Since the beginning of clinical use of MRI, many research groups have developed methods to suppress or correct motion artefacts. This review focuses on rigid body motion correction of head and brain MRI and its application in diagnosis and research. It explains the sources and types of motion and related artefacts, classifies and describes existing techniques for motion detection, compensation and correction and lists established and experimental approaches. Retrospective motion correction modifies the MR image data during the reconstruction, while prospective motion correction performs an adaptive update of the data acquisition. Differences, benefits and drawbacks of different motion correction methods are discussed.
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Affiliation(s)
- F Godenschweger
- Biomedical Magnetic Resonance, Otto-von-Guericke University, Magdeburg, Germany
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Juchem C, Nahhass OM, Nixon TW, de Graaf RA. Multi-slice MRI with the dynamic multi-coil technique. NMR IN BIOMEDICINE 2015; 28:1526-34. [PMID: 26419649 PMCID: PMC4710146 DOI: 10.1002/nbm.3414] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 08/10/2015] [Accepted: 08/25/2015] [Indexed: 05/22/2023]
Abstract
To date, spatial encoding for MRI is based on linear X, Y and Z field gradients generated by dedicated X, Y and Z wire patterns. We recently introduced the dynamic multi-coil technique (DYNAMITE) for the generation of magnetic field shapes for biomedical MR applications from a set of individually driven localized coils. The benefits for B0 magnetic field homogenization have been shown, as well as proof of principle of radial and algebraic MRI. In this study the potential of DYNAMITE MRI is explored further and the first multi-slice MRI implementation in which all gradient fields are purely DYNAMITE based is presented. The obtained image fidelity is shown to be virtually identical to that of a conventional MRI system with dedicated X, Y and Z gradient coils. Comparable image quality is a milestone towards the establishment of fully functional DYNAMITE MRI (and shim) systems.
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Affiliation(s)
- Christoph Juchem
- Yale University School of Medicine, Department of Diagnostic Radiology, MR Research Center (MRRC), New Haven, CT 06520, USA
| | | | - Terence W. Nixon
- Yale University School of Medicine, Department of Diagnostic Radiology, MR Research Center (MRRC), New Haven, CT 06520, USA
| | - Robin A. de Graaf
- Yale University School of Medicine, Department of Diagnostic Radiology, MR Research Center (MRRC), New Haven, CT 06520, USA
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7
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N. Hahn B. Dynamic linear inverse problems with moderate movements of the object: Ill-posedness and regularization. ACTA ACUST UNITED AC 2015. [DOI: 10.3934/ipi.2015.9.395] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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8
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Sengupta S, Smith DS, Welch EB. Continuously moving table MRI with golden angle radial sampling. Magn Reson Med 2014; 74:1690-7. [PMID: 25461600 DOI: 10.1002/mrm.25531] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 10/13/2014] [Accepted: 10/24/2014] [Indexed: 11/09/2022]
Abstract
PURPOSE Continuously moving table (CMT) MRI is a high throughput technique that has multiple applications in whole-body imaging. In this work, CMT MRI based on golden angle (GA, 111.246° azimuthal step) radial sampling is developed at 3 Tesla (T), with the goal of increased flexibility in image reconstruction using arbitrary profile groupings. THEORY AND METHODS CMT MRI with GA and linear angle (LA) schemes were developed for whole-body imaging at 3T with a table speed of 20 mm/s. Imaging was performed in phantoms and a human volunteer with extended z fields of view of up to 1.8 meters. Four separate LA and a single GA scan were performed to enable slice reconstructions at four different thicknesses. RESULTS GA CMT MRI produced high image quality in phantoms and humans and allowed complete flexibility in reconstruction of slices with arbitrary slice thickness and position from a single data set. LA CMT MRI was constrained by predetermined parameters, required multiple scans and suffered from stair step artifacts that were not present in GA images. CONCLUSION GA sampling provides a robust flexible approach to CMT whole-body MRI with the ability to reconstruct slices at arbitrary positions and thicknesses from a single scan.
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Affiliation(s)
- Saikat Sengupta
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - David S Smith
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - E Brian Welch
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, Tennessee, USA.,Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
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9
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Hegde SS, Zhang Y, Bottomley PA. Acceleration and motion-correction techniques for high-resolution intravascular MRI. Magn Reson Med 2014; 74:452-61. [PMID: 25163750 DOI: 10.1002/mrm.25436] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 08/06/2014] [Accepted: 08/11/2014] [Indexed: 11/07/2022]
Abstract
PURPOSE High-resolution intravascular (IV) MRI is susceptible to degradation from physiological motion and requires high frame-rates for true endoscopy. Traditional cardiac-gating techniques compromise efficiency by reducing the effective scan rate. Here we test whether compressed sensing (CS) reconstruction and ungated motion-compensation using projection shifting, could provide faster motion-suppressed, IVMRI. THEORY AND METHODS CS reconstruction is developed for undersampled Cartesian and radial imaging using a new IVMRI-specific cost function to effectively increase imaging speed. A new motion correction method is presented wherein individual IVMRI projections are shifted based on the IVMRI detector's intrinsic amplitude and phase properties. The methods are tested at 3 Tesla (T) in fruit, human vessel specimens, and a rabbit aorta in vivo. Images are compared using structural-similarity and "spokal variation" indices. RESULTS Although some residual artifacts persisted, CS acceleration and radial motion compensation strategies reduced motion artifact in vitro and in vivo, allowing effective accelerations of up to eight-fold at 200-300 µm resolution. CONCLUSION The 3T IVMRI detectors are well-suited to CS and motion correction strategies based on their intrinsic radially-sparse sensitivity profiles and high signal-to-noise ratios.
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Affiliation(s)
- Shashank Sathyanarayana Hegde
- Russell H. Morgan Department of Radiology & Radiological Sciences, Johns Hopkins University, Baltimore, Maryland, USA
| | - Yi Zhang
- Russell H. Morgan Department of Radiology & Radiological Sciences, Johns Hopkins University, Baltimore, Maryland, USA.,Department of Electrical & Computer Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Paul A Bottomley
- Russell H. Morgan Department of Radiology & Radiological Sciences, Johns Hopkins University, Baltimore, Maryland, USA.,Department of Electrical & Computer Engineering, Johns Hopkins University, Baltimore, Maryland, USA
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10
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Jonathan SV, Vakil P, Jeong YI, Menon RG, Ansari SA, Carroll TJ. RAZER: a pulse sequence for whole-brain bolus tracking at high frame rates. Magn Reson Med 2013; 71:2127-38. [PMID: 23878107 DOI: 10.1002/mrm.24882] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 05/30/2013] [Accepted: 06/20/2013] [Indexed: 11/12/2022]
Abstract
PURPOSE To introduce a pulse sequence that obtains whole-brain perfusion measurements at 1.7 mm isotropic voxel resolution by dynamic susceptibility contrast MRI bolus tracking despite using a temporal resolution of 10.3 s: RAdial kZ-blipped 3D GRE-echo-planar imaging (GRE-EPI) for whole-brain pERfusion (RAZER). METHODS In RAZER, in-plane radial and through-plane 3D GRE-EPI Cartesian sampling was used to produce a 3D stack-of-stars k-space. In vivo scans on one healthy volunteer and one patient with Moyamoya disease were performed using RAZER and a typical 2D GRE-EPI pulse sequence as a reference standard. Agreement in perfusion metrics was reported using linear regression analysis and Bland-Altman plots. RESULTS Sliding window reconstruction recovered dynamic information lost in the large temporal acquisition window of RAZER. Inline phase correction scans corrected N/2 ghosting artifacts and view-dependent phase variations. Whole-brain images of cerebral blood volume, cerebral blood flow, and mean transit time were calculated with RAZER at 1.7 mm isotropic voxel resolution and good reference standard agreement in both subjects when sliding window reconstruction was used (r(2) > 0.7, mean bias in mean transit time measurements < 0.5 s). CONCLUSIONS Despite using a temporal resolution of 10.3 s, in vivo data indicates that RAZER is able to obtain whole-brain perfusion measurements at 1.7 mm isotropic voxel resolution and good reference standard agreement.
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Affiliation(s)
- Sumeeth V Jonathan
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, USA; Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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11
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Moussavi A, Untenberger M, Uecker M, Frahm J. Correction of gradient-induced phase errors in radial MRI. Magn Reson Med 2013; 71:308-12. [PMID: 23440722 DOI: 10.1002/mrm.24643] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Revised: 12/15/2012] [Accepted: 12/31/2012] [Indexed: 11/09/2022]
Abstract
PURPOSE To correct gradient-induced phase errors in radial MRI. METHODS Gradient-induced eddy currents affect the MRI data acquisition by gradient delays and phase errors that may lead to severe image artifacts for non-Cartesian imaging scenarios such as radial trajectories. While gradient delays are dealt with by respective shifts of the acquisition window during radial image acquisition, this work introduces a simple method for quantifying and correcting phase errors from the actual data prior to image reconstruction. For a given gradient system, the approach yields a specific phase error per gradient that can be used for correcting the raw data. RESULTS Phantom studies at 9.4 T demonstrated marked improvements in radial image quality. It could be shown that the phase correction is not compromised by data undersampling. Moreover, the selective correction of gradient-induced phase errors retained the phase information caused by different concentrations of a paramagnetic contrast agent. CONCLUSION The proposed method does not require additional reference measurements and separately corrects for phase errors induced by eddy currents, while retaining the residual phase of the object which may carry physiologic information.
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Affiliation(s)
- Amir Moussavi
- Biomedizinische NMR Forschungs GmbH am MPI für biophysikalische Chemie, Göttingen, Germany; DFG Research Center for Molecular Physiology of the Brain (CMPB), Göttingen, Germany
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12
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Johnson KO, Robison RK, Pipe JG. Rigid body motion compensation for spiral projection imaging. IEEE TRANSACTIONS ON MEDICAL IMAGING 2011; 30:655-665. [PMID: 21062678 DOI: 10.1109/tmi.2010.2091146] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Spiral projection imaging (SPI) is a 3D, spiral based magnetic resonance imaging (MRI) acquisition scheme that allows for self-navigated motion estimation of all six degrees-of-freedom. The trajectory, a set of spiral planes, is enhanced to accommodate motion tracking by adding orthogonal planes. Rigid-body motion tracking is accomplished by comparing the overlapping data and deducing the motion that is consistent with the comparisons. The accuracy of the proposed method is quantified for simulated data and for data collected using both a phantom and a volunteer. These tests were repeated to measure the effect of off-resonance blurring, coil sensitivity, gradient warping, undersampling, and nonrigid motion (e.g., neck). The artifacts of off-resonance, coils sensitivity, and gradient warping impose an unnotable effect on the accuracy of motion estimation. The worst mean accuracy is 0.15° and 0.20 mm for the phantom while the worst mean accuracy is 0.48° and 0.34 mm when imaging a brain, indicating that the nonrigid component in human subjects slightly degrades accuracy. When applied to in vivo motion, the proposed technique considerably reduces motion artifact.
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Affiliation(s)
- Kenneth O Johnson
- Keller Center for Imaging Innvation, Barrow Neurological Institute, Phoenix, AZ 85013, USA
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13
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Mendes J, Parker DL. Intrinsic detection of motion in segmented sequences. Magn Reson Med 2010; 65:1084-9. [PMID: 21413072 DOI: 10.1002/mrm.22681] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 09/09/2010] [Accepted: 09/19/2010] [Indexed: 11/08/2022]
Abstract
While many motion correction techniques for MRI have been proposed, their use is often limited by increased patient preparation, decreased patient comfort, additional scan time, or the use of specialized sequences not available on many commercial scanners. For this reason, we propose a simple self-navigating technique designed to detect motion in segmented sequences. We demonstrate that comparing two segments containing adjacent sets of k-space lines results in an aliased error function. A global shift of the aliased error function indicates the presence of in-plane rigid-body translation, while other types of motion are evident in the dispersion or breadth of the error function. Since segmented sequences commonly acquire data in sets of adjacent k-space lines, this method provides these sequences with an inherent method of detecting object motion. Motion corrupted data can then be reacquired proactively or in some cases corrected or removed retrospectively.
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Affiliation(s)
- Jason Mendes
- Department of Radiology, Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, Utah 84108, USA
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14
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Automatic correction of in-plane bulk motion artifacts in self-navigated radial MRI. Magn Reson Imaging 2008; 26:367-78. [PMID: 18068927 DOI: 10.1016/j.mri.2007.08.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Revised: 08/03/2007] [Accepted: 08/08/2007] [Indexed: 11/24/2022]
Abstract
Radial MRI is typically used for scans that are sensitive to unavoidable motion. While the translational motion artifact can be easily removed from the radial trajectory data by phase correction, correction of rotational motion still remains a challenge in radial MRI. We present a novel method to refocus the image corrupted by view-to-view motion in the view-interleaved radial MRI data. In this method, the error in rotational view angles was modeled as a polynomial function of the view order and the model parameters were estimated by minimizing the self-navigator image metrics such as image entropy, gradient entropy, normalized gradient squared and mean square difference. Translational motion correction was conducted by aligning the projection profiles. Simulation studies were conducted to demonstrate the robustness of both translational and rotational motion correction methods in different noise levels. The proposed method was successfully applied to correct for motion of healthy subjects. Substantial motion correction with relative error of less than 5% was achieved by using either first- or second-order model with the image metrics. This study demonstrates the potential of the method for motion-sensitive applications.
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15
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Stehning C, Boernert P, Nehrke K. Advances in Coronary MRA from Vessel Wall to Whole Heart Imaging. Magn Reson Med Sci 2007; 6:157-70. [PMID: 18037796 DOI: 10.2463/mrms.6.157] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Dold C, Zaitsev M, Speck O, Firle EA, Hennig J, Sakas G. Advantages and limitations of prospective head motion compensation for MRI using an optical motion tracking device. Acad Radiol 2006; 13:1093-103. [PMID: 16935721 DOI: 10.1016/j.acra.2006.05.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2006] [Revised: 05/18/2006] [Accepted: 05/23/2006] [Indexed: 11/25/2022]
Abstract
RATIONALE AND OBJECTIVES Subject motion appears to be a limiting factor in numerous magnetic resonance (MR) imaging (MRI) applications. In particular, head tremor, which often accompanies stroke, may render certain high-resolution two- (2D) and three-dimensional (3D) techniques inapplicable. The reason for that is head movement during acquisition. The study objective is to achieve a method able to compensate for complete motion during data acquisition. The method should be usable for every sequence and easily implemented on different MR scanners. MATERIALS AND METHODS The possibility of interfacing the MR scanner with an external optical motion-tracking system capable of determining the object's position with submillimeter accuracy and an update rate of 60 Hz is shown. Movement information on the object position (head) is used to compensate for motion in real time by updating the field of view (FOV) by recalculating the gradients and radiofrequency parameter of the MR scanner during acquisition of k-space data, based on tracking data. RESULTS Results of rotation phantom, in vivo experiments, and implementation of three different MRI sequences, 2D spin echo, 3D gradient echo, and echo planar imaging, are presented. Finally, the proposed method is compared with the prospective motion correction software available on the scanner software. CONCLUSION A prospective motion correction method that works in real time only by updating the FOV of the MR scanner is presented. Results show the feasibility of using an external optical motion-tracking system to compensate for strong and fast subject motion during acquisition.
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Affiliation(s)
- Christian Dold
- Department of Cognitive Computing and Medical Imaging, Fraunhofer Gesellschaft, Institute for Computer Graphics, Fraunhoferstr 5, D-64283 Darmstadt, Germany.
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17
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Dold C, Zaitsev M, Speck O, Firle EA, Hennig J, Sakas G. Prospective head motion compensation for MRI by updating the gradients and radio frequency during data acquisition. ACTA ACUST UNITED AC 2006; 8:482-9. [PMID: 16685881 DOI: 10.1007/11566465_60] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Subject motion appears to be a limiting factor in numerous magnetic resonance imaging (MRI) applications. For head imaging the subject's ability to maintain the same head position for a considerable period of time places restrictions on the total acquisition time. For healthy individuals this time typically does not exceed 10 minutes and may be considerably reduced in case of pathology. In particular, head tremor, which often accompanies stroke, may render certain high-resolution 2D and 3D techniques inapplicable. Several navigator techniques have been proposed to circumvent the subject motion problem. The most suitable for head imaging appears to be the orbital or spherical navigator methods. Navigators, however, not only lengthen the measurement because of the time required for acquisition of the position information, but also require additional excitation radio frequency (RF) pulses to be incorporated into the sequence timing, which disturbs the steady state. Here we demonstrate the possibility of interfacing the MR scanner with an external optical motion tracking system, capable of determining the object's position with sub-millimeter accuracy and an update rate of 60Hz. The movement information on the object position (head) is used to compensate the motion in real time. This is done by updating the field of view (FOV) by recalculating the gradients and the RF-parameter of the MRI tomograph during the acquisition of k-space data based on the tracking data. Results of rotation phantom, in vivo experiments and the implementation in two different MRI sequences are presented.
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Affiliation(s)
- Christian Dold
- Fraunhofer Institute for Computer Graphics, Dept. Cognitive Computing & Medical Imaging, Darmstadt, Germany.
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Stehning C, Börnert P, Nehrke K, Eggers H, Stuber M. Free-breathing whole-heart coronary MRA with 3D radial SSFP and self-navigated image reconstruction. Magn Reson Med 2005; 54:476-80. [PMID: 16032682 DOI: 10.1002/mrm.20557] [Citation(s) in RCA: 187] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Respiratory motion is a major source of artifacts in cardiac magnetic resonance imaging (MRI). Free-breathing techniques with pencil-beam navigators efficiently suppress respiratory motion and minimize the need for patient cooperation. However, the correlation between the measured navigator position and the actual position of the heart may be adversely affected by hysteretic effects, navigator position, and temporal delays between the navigators and the image acquisition. In addition, irregular breathing patterns during navigator-gated scanning may result in low scan efficiency and prolonged scan time. The purpose of this study was to develop and implement a self-navigated, free-breathing, whole-heart 3D coronary MRI technique that would overcome these shortcomings and improve the ease-of-use of coronary MRI. A signal synchronous with respiration was extracted directly from the echoes acquired for imaging, and the motion information was used for retrospective, rigid-body, through-plane motion correction. The images obtained from the self-navigated reconstruction were compared with the results from conventional, prospective, pencil-beam navigator tracking. Image quality was improved in phantom studies using self-navigation, while equivalent results were obtained with both techniques in preliminary in vivo studies.
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Affiliation(s)
- C Stehning
- Institute of Biomedical Engineering, Karlsruhe, Germany
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Bernstein MA, Shu Y, Elliott AM. RINGLET motion correction for 3D MRI acquired with the elliptical centric view order. Magn Reson Med 2004; 50:802-12. [PMID: 14523967 DOI: 10.1002/mrm.10584] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A new rigid-body motion correction algorithm is described that is compatible with 3D image sets acquired with the elliptical centric (EC) view order. With this view order, an annular ring of k-space data is acquired in the ky-kz plane during any short time interval. Images for tracking motion can be reconstructed in the yz-plane from any ring of the acquisition data. In these tracking images, a point source (such as an external marker) shows a characteristic bull's-eye pattern that permits motion monitoring and correction. The true position of the point object is located at the center of the bull's-eye pattern. Cross correlation can be performed to automatically track the positions of markers reconstructed from adjacent rings of k-space. To increase the marker signal, the markers are encased in inductively coupled RF coils. Rigid-body motion in the yz-plane is calculated directly with the Euclidean group for rotation and translation, and corrected by rotating and applying phase shifts to any corrupted rings of data. In the current work we present a theoretical analysis of this method, as well as results of volunteer and controlled phantom experiments that demonstrate its initial feasibility. Although the EC view order has mainly been used for MR angiography (MRA), it can also be used for most 3D acquisitions.
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Welch EB, Rossman PJ, Felmlee JP, Manduca A. Self-navigated motion correction using moments of spatial projections in radial MRI. Magn Reson Med 2004; 52:337-45. [PMID: 15282816 DOI: 10.1002/mrm.20151] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Interest in radial MRI (also known as projection reconstruction (PR) MRI) has increased recently for uses such as fast scanning and undersampled acquisitions. Additionally, PR acquisitions offer intrinsic advantages over standard two-dimensional Fourier transform (2DFT) imaging with respect to motion of the imaged object. It is well known that aligning each spatial domain projection's center of mass (calculated using the 0th and 1st moments) to the center of the field of view (FOV) corrects shifts caused by in-plane translation. In this work, a previously unrealized ability to determine the in-plane rotational motion of an imaged object using the 2nd moments of the spatial domain projections in conjunction with a specific projection angle acquisition time order is reported. We performed the correction using only the PR data itself acquired with the newly proposed projection angle acquisition time order. With the proposed view angle acquisition order, the acquisition is "self-navigating" with respect to both in-plane translation and rotation. We reconstructed the images using the aligned projections and detected acquisition angles to significantly reduce image artifacts due to such motion. The theory of the correction technique is described, and its effectiveness is demonstrated in phantom and in vivo experiments.
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Affiliation(s)
- Edward Brian Welch
- MRI Research Laboratory, Department of Diagnostic Radiology, Mayo Clinic, Rochester, Minnesota 55905, USA
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Shankaranarayanan A, Herfkens R, Hargreaves BM, Polzin JA, Santos JM, Brittain JH. Helical MR: Continuously moving table axial imaging with radial acquisitions. Magn Reson Med 2003; 50:1053-60. [PMID: 14587016 DOI: 10.1002/mrm.10621] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A technique for extended field of view MRI is presented. Similar to helical computed tomography, the method utilizes a continuously moving patient table, a 2D axial slice that remains fixed relative to the MRI magnet, and a radial k-space trajectory. A fully refocused SSFP acquisition enables spatial resolution comparable to current clinical protocols in scan times that are sufficiently short to allow a reasonable breathhold duration. RF transmission and signal reception are performed using the RF body coil and the images are reconstructed in real time. Experimental results are presented that illustrate the technique's ability to resolve small structures in the table-motion direction. Simulation experiments to study the steady-state response of the fully refocused SSFP acquisition during continuous table motion are also presented. Finally, whole body images of healthy volunteers demonstrate the high image quality achieved using the helical MRI approach.
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Moriguchi H, Lewin JS, Duerk JL. Novel interleaved spiral imaging motion correction technique using orbital navigators. Magn Reson Med 2003; 50:423-8. [PMID: 12876721 DOI: 10.1002/mrm.10507] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Although spiral imaging seldom produces apparent artifacts related to flow, it remains sensitive to rapid object motion. In this article, a new correction method is presented for rapid rigid body motion in interleaved spiral imaging. With this technique, an identical circular navigator k-space trajectory is linked to each spiral trajectory. Data inconsistency due to both rotation and translation among spiral interleaves can be corrected by evaluating the magnitudes and phases of the data contained in the navigator "ring." Further, it is difficult to create a frequency field map for off-resonance correction when an object moves during a scan, because there is motion-dependent misregistration between the two images acquired with different TEs. However, this difficulty can be overcome by combining the motion-correction method with a recently proposed technique (off-resonance correction using variable-density spirals (ORC-VDS)), thereby enabling both motion compensation and off-resonance correction with no additional scanning.
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Affiliation(s)
- Hisamoto Moriguchi
- Department of Radiology, University Hospitals of Cleveland and Case Western Reserve University, Cleveland, Ohio 44106, USA
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Welch EB, Felmlee JP, Ehman RL, Manduca A. Motion correction using the k-space phase difference of orthogonal acquisitions. Magn Reson Med 2002; 48:147-56. [PMID: 12111942 DOI: 10.1002/mrm.10179] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Rigid body translations of an object in MRI create image artifacts along the phase-encode (PE) direction in standard 2DFT imaging. If two images are acquired with swapped PE direction, it is possible to determine and correct for arbitrary in-plane translational interview motions in both images directly from phase differences in the k-space acquisitions by solving a large system of linear equations. For example, if one assumes two N x N 2D acquisitions with in-plane translational interview motion, 4N unknown motions may corrupt the two images, but the phase difference at each point in k-space yields a system of N(2) equations in these 4N unknowns. If the acquisitions have orthogonal PE directions, this highly overdetermined system of equations can be solved to provide the motion records, which in turn can be used to correct the motion artifacts in each image. The theory of this orthogonal k-space phase difference (ORKPHAD) technique is described, and results are presented for synthetic and in vivo motion-corrupted data sets. In all cases, the data showed clear improvement of translation-induced artifacts. These methods do not require special pulse sequences and are theoretically generalizable to partial Fourier imaging and 3D acquisitions.
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Affiliation(s)
- Edward Brian Welch
- MRI Research Laboratory, Department of Diagnostic Radiology, Mayo Clinic, Rochester, Minnesota 55905, USA
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Welch EB, Manduca A, Grimm RC, Ward HA, Jack CR. Spherical navigator echoes for full 3D rigid body motion measurement in MRI. Magn Reson Med 2002; 47:32-41. [PMID: 11754440 DOI: 10.1002/mrm.10012] [Citation(s) in RCA: 149] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We developed a 3D spherical navigator (SNAV) echo technique that can measure rigid body motion in all six degrees of freedom simultaneously by sampling a spherical shell in k-space. 3D rotations of an imaged object simply rotate the data on this shell and can be detected by registration of k-space magnitude values. 3D translations add phase shifts to the data on the shell and can be detected with a weighted least-squares fit to the phase differences at corresponding points. MRI pulse sequences were developed to study k-space sampling strategies on such a shell. Data collected with a computer-controlled motion phantom with known rotational and translational motions were used to evaluate the technique. The accuracy and precision of the technique depend on the sampling density. Roughly 2000 sample points were necessary for accurate detection to within the error limits of the motion phantom when using a prototype time-intensive sampling method. This number of samples can be captured in an approximately 27-ms double excitation SNAV pulse sequence with a 3D helical spiral trajectory. Preliminary results with the helical SNAV are encouraging and indicate that accurate motion measurement suitable for retrospective or prospective correction should be feasible with SNAV echoes.
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Affiliation(s)
- Edward Brian Welch
- MRI Research Lab, Department of Diagnostic Radiology, Mayo Clinic, Rochester, Minnesota 55905, USA
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Beckmann N, Gentsch C, Baumann D, Bruttel K, Vassout A, Schoeffter P, Loetscher E, Bobadilla M, Perentes E, Rudin M. Current awareness. NMR IN BIOMEDICINE 2001; 14:217-222. [PMID: 11357188 DOI: 10.1002/nbm.669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In order to keep subscribers up-to-date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of NMR in biomedicine. Each bibliography is divided into 9 sections: 1 Books, Reviews ' Symposia; 2 General; 3 Technology; 4 Brain and Nerves; 5 Neuropathology; 6 Cancer; 7 Cardiac, Vascular and Respiratory Systems; 8 Liver, Kidney and Other Organs; 9 Muscle and Orthopaedic. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted.
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Affiliation(s)
- N Beckmann
- Core Technologies Area, Novartis Pharma AG, CH-4002 Basel, Switzerland
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