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Compressed sensing

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https://www.readbyqxmd.com/read/28942124/the-effects-of-freedom-of-choice-in-action-selection-on-perceived-mental-effort-and-the-sense-of-agency
#1
Zeynep Barlas, William E Hockley, Sukhvinder S Obhi
Previous research showed that increasing the number of action alternatives enhances the sense of agency (SoA). Here, we investigated whether choice space could affect subjective judgments of mental effort experienced during action selection and examined the link between subjective effort and the SoA. Participants performed freely selected (among two, three, or four options) and instructed actions that produced pleasant or unpleasant tones. We obtained action-effect interval estimates to quantify intentional binding - the perceived interval compression between actions and outcomes and feeling of control (FoC) ratings...
September 20, 2017: Acta Psychologica
https://www.readbyqxmd.com/read/28940951/instrument-visualization-using-conventional-and-compressed-sensing-semac-for-interventional-mri-at-3t
#2
Lena Sonnow, Wesley D Gilson, Esther Raithel, Mathias Nittka, Frank Wacker, Jan Fritz
BACKGROUND: Interventional magnetic resonance imaging (MRI) at 3T benefits from higher spatial and temporal resolution, but artifacts of metallic instruments are often larger and may obscure target structures. PURPOSE: To test that compressed sensing (CS) slice-encoding metal artifact correction (SEMAC) is feasible for 3T interventional MRI and affords more accurate instrument visualization than turbo spin echo (TSE) and gradient echo (GRE) techniques, and facilitates faster data acquisition than conventional SEMAC...
September 21, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28940748/rapid-compressed-sensing-reconstruction-of-3d-non-cartesian-mri
#3
Corey A Baron, Nicholas Dwork, John M Pauly, Dwight G Nishimura
PURPOSE: Conventional non-Cartesian compressed sensing requires multiple nonuniform Fourier transforms every iteration, which is computationally expensive. Accordingly, time-consuming reconstructions have slowed the adoption of undersampled 3D non-Cartesian acquisitions into clinical protocols. In this work we investigate several approaches to minimize reconstruction times without sacrificing accuracy. METHODS: The reconstruction problem can be reformatted to exploit the Toeplitz structure of matrices that are evaluated every iteration, but it requires larger oversampling than what is strictly required by nonuniform Fourier transforms...
September 23, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28932236/quantitative-evaluation-of-temporal-regularizers-in-compressed-sensing-dynamic-contrast-enhanced-mri-of-the-breast
#4
Dong Wang, Lori R Arlinghaus, Thomas E Yankeelov, Xiaoping Yang, David S Smith
PURPOSE: Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) is used in cancer imaging to probe tumor vascular properties. Compressed sensing (CS) theory makes it possible to recover MR images from randomly undersampled k-space data using nonlinear recovery schemes. The purpose of this paper is to quantitatively evaluate common temporal sparsity-promoting regularizers for CS DCE-MRI of the breast. METHODS: We considered five ubiquitous temporal regularizers on 4...
2017: International Journal of Biomedical Imaging
https://www.readbyqxmd.com/read/28921631/validation-of-highly-accelerated-real-time-cardiac-cine-mri-with-radial-k-space-sampling-and-compressed-sensing-in-patients-at-1-5t-and-3t
#5
Hassan Haji-Valizadeh, Amir A Rahsepar, Jeremy D Collins, Elwin Bassett, Tamara Isakova, Tobias Block, Ganesh Adluru, Edward V R DiBella, Daniel C Lee, James C Carr, Daniel Kim
PURPOSE: To validate an optimal 12-fold accelerated real-time cine MRI pulse sequence with radial k-space sampling and compressed sensing (CS) in patients at 1.5T and 3T. METHODS: We used two strategies to reduce image artifacts arising from gradient delays and eddy currents in radial k-space sampling with balanced steady-state free precession readout. We validated this pulse sequence against a standard breath-hold cine sequence in two patient cohorts: a myocardial infarction (n = 16) group at 1...
September 17, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28920907/energy-analysis-of-decoders-for-rakeness-based-compressed-sensing-of-ecg-signals
#6
Fabio Pareschi, Mauro Mangia, Daniele Bortolotti, Andrea Bartolini, Luca Benini, Riccardo Rovatti, Gianluca Setti
In recent years, compressed sensing (CS) has proved to be effective in lowering the power consumption of sensing nodes in biomedical signal processing devices. This is due to the fact the CS is capable of reducing the amount of data to be transmitted to ensure correct reconstruction of the acquired waveforms. Rakeness-based CS has been introduced to further reduce the amount of transmitted data by exploiting the uneven distribution to the sensed signal energy. Yet, so far no thorough analysis exists on the impact of its adoption on CS decoder performance...
September 13, 2017: IEEE Transactions on Biomedical Circuits and Systems
https://www.readbyqxmd.com/read/28920895/matched-filtering-for-heart-rate-estimation-on-compressive-sensing-ecg-measurements
#7
Giulia Da Poian, Christopher J Rozell, Riccardo Bernardini, Roberto Rinaldo, Gari D Clifford
OBJECTIVE: Compressive Sensing (CS) has recently been applied as a low complexity compression framework for long-term monitoring of electrocardiogram signals using Wireless Body Sensor Networks. Long-term recording of ECG signals can be useful for diagnostic purposes and to monitor the evolution of several widespread diseases. In particular, beat to beat intervals provide important clinical information, and these can be derived from the ECG signal by computing the distance between QRS complexes (R-peaks)...
September 14, 2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28906567/self-calibrating-wave-encoded-variable-density-single-shot-fast-spin-echo-imaging
#8
Feiyu Chen, Valentina Taviani, Jonathan I Tamir, Joseph Y Cheng, Tao Zhang, Qiong Song, Brian A Hargreaves, John M Pauly, Shreyas S Vasanawala
BACKGROUND: It is highly desirable in clinical abdominal MR scans to accelerate single-shot fast spin echo (SSFSE) imaging and reduce blurring due to T2 decay and partial-Fourier acquisition. PURPOSE: To develop and investigate the clinical feasibility of wave-encoded variable-density SSFSE imaging for improved image quality and scan time reduction. STUDY TYPE: Prospective controlled clinical trial. SUBJECTS: With Institutional Review Board approval and informed consent, the proposed method was assessed on 20 consecutive adult patients (10 male, 10 female, range, 24-84 years)...
September 14, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28902600/contact-analysis-of-horizontal-cleavage-tear-treatment
#9
Carlos Uquillas, Sally Arno, Austin Ramme, Cheongeun Oh, Peter Walker, Robert Meislin
Horizontal cleavage tears (HCT) commonly occur in the posterior horn of the medial meniscus due to aging and degeneration. The purpose of this study was to investigate the surgical treatment of HCTs and their effect on dynamic tibiofemoral contact mechanics. The tibiofemoral contact mechanics of 10 cadaver knees were investigated using a custom dynamic loading apparatus, pressure sensor, and motion sensing camera. Three loading conditions were analyzed: 500 N compressive load, 500 N compressive load with 100 N posterior shear, and 500 N compressive load with 2...
May 2017: Bulletin of the Hospital for Joint Diseases
https://www.readbyqxmd.com/read/28893651/obstructive-sleep-apnea-is-associated-with-altered-midbrain-chemical-concentrations
#10
Paul M Macey, Manoj K Sarma, Janani P Prasad, Jennifer A Ogren, Ravi Aysola, Ronald M Harper, M Albert Thomas
Obstructive sleep apnea (OSA) is accompanied by altered structure and function in cortical, limbic, brainstem, and cerebellar regions. The midbrain is relatively unexamined, but contains many integrative nuclei which mediate physiological functions that are disrupted in OSA. We therefore assessed the chemistry of the midbrain in OSA in this exploratory study. We used a recently-developed accelerated 2D magnetic resonance spectroscopy (2D-MRS) technique, compressed sensing-based 4D echo-planar J-resolved spectroscopic imaging (4D-EP-JRESI), to measure metabolites in the midbrain of 14 OSA (mean age±SD:54...
September 8, 2017: Neuroscience
https://www.readbyqxmd.com/read/28893337/optimization-of-three-dimensional-3d-chemical-imaging-by-soft-x-ray-spectro-tomography-using-a-compressed-sensing-algorithm
#11
Juan Wu, Mirna Lerotic, Sean Collins, Rowan Leary, Zineb Saghi, Paul Midgley, Slava Berejnov, Darija Susac, Juergen Stumper, Gurvinder Singh, Adam P Hitchcock
Soft X-ray spectro-tomography provides three-dimensional (3D) chemical mapping based on natural X-ray absorption properties. Since radiation damage is intrinsic to X-ray absorption, it is important to find ways to maximize signal within a given dose. For tomography, using the smallest number of tilt series images that gives a faithful reconstruction is one such method. Compressed sensing (CS) methods have relatively recently been applied to tomographic reconstruction algorithms, providing faithful 3D reconstructions with a much smaller number of projection images than when conventional reconstruction methods are used...
September 12, 2017: Microscopy and Microanalysis
https://www.readbyqxmd.com/read/28873255/accelerated-4d-self-gated-mri-of-tibiofemoral-kinematics
#12
Valentina Mazzoli, Jasper Schoormans, Martijn Froeling, Andre M Sprengers, Bram F Coolen, Nico Verdonschot, Gustav J Strijkers, Aart J Nederveen
Anatomical (static) magnetic resonance imaging (MRI) is the most useful imaging technique for the evaluation and assessment of internal derangement of the knee, but does not provide dynamic information and does not allow the study of the interaction of the different tissues during motion. As knee pain is often only experienced during dynamic tasks, the ability to obtain four-dimensional (4D) images of the knee during motion could improve the diagnosis and provide a deeper understanding of the knee joint. In this work, we present a novel approach for dynamic, high-resolution, 4D imaging of the freely moving knee without the need for external triggering...
September 5, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28873057/similarity-of-scenic-bilevel-images
#13
Yuanhao Zhai, David L Neuhoff
This paper presents a study of bilevel image similarity, including new objective metrics intended to quantify similarity consistent with human perception, and a subjective experiment to obtain ground truth for judging the performance of the objective similarity metrics. The focus is on scenic bilevel images, which are complex, natural or hand-drawn images, such as landscapes or portraits. The ground truth was obtained from ratings by 77 subjects of 44 distorted versions of seven scenic images, using a modified version of the SDSCE testing methodology...
November 2016: IEEE Transactions on Image Processing: a Publication of the IEEE Signal Processing Society
https://www.readbyqxmd.com/read/28870227/cone-beam-ct-reconstruction-for-non-periodic-organ-motion-using-time-ordered-chain-graph-model
#14
Masahiro Nakano, Akihiro Haga, Jun'ichi Kotoku, Taiki Magome, Yoshitaka Masutani, Shouhei Hanaoka, Satoshi Kida, Keiichi Nakagawa
PURPOSE: The purpose of this study is to introduce the new concept of a four-dimensional (4D) cone-beam computed tomography (CBCT) reconstruction approach for non-periodic organ motion in cooperation with the time-ordered chain graph model (TCGM) and to compare it with previously developed methods such as total variation-based compressed sensing (TVCS) and prior-image constrained compressed sensing (PICCS). MATERIALS AND METHODS: Our proposed reconstruction is based on a model including the constraint originating from the images of neighboring time phases...
September 4, 2017: Radiation Oncology
https://www.readbyqxmd.com/read/28867669/constrained-data-extrapolation-code-a-new-approach-for-high-definition-vascular-imaging-from-low-resolution-data
#15
Yang Song, Ehsan Hamtaei, Sean K Sethi, Guang Yang, Haibin Xie, E Mark Haacke
PURPOSE: To introduce a new approach to reconstruct high definition vascular images using COnstrained Data Extrapolation (CODE) and evaluate its capability in estimating vessel area and stenosis. MATERIALS AND METHODS: CODE is based on the constraint that the full width half maximum of a vessel can be accurately estimated and, since it represents the best estimate for the width of the object, higher k-space data can be generated from this information. To demonstrate the potential of extracting high definition vessel edges using low resolution data, both simulated and human data were analyzed to better visualize the vessels and to quantify both area and stenosis measurements...
September 1, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28866485/learning-joint-sparse-codes-for-calibration-free-parallel-mr-imaging-lindberg
#16
Shanshan Wang, Sha Tan, Yuan Gao, Qiegen Liu, Leslie Ying, Taohui Xiao, Yuanyuan Liu, Xin Liu, Hairong Zheng, Dong Liang
The integration of compressed sensing and parallel imaging (CS-PI) has shown an increased popularity in recent years to accelerate MR imaging. Among them, calibration-free techniques have presented encouraging performances due to its capability in robustly handling the sensitivity information. Unfortunately, existing calibration-free methods have only explored joint-sparsity with direct analysis transform projections. To further exploit joint-sparsity and improve reconstruction accuracy, this paper proposes to Learn joINt-sparse coDes for caliBrationfree parallEl mR imaGing (LINDBERG) by modelling the parallel MR imaging problem as an ℓ2-ℓF-ℓ2,1 minimization objective with an ℓ2 norm constraining data fidelity, Frobenius norm enforcing sparse representation error and the ℓ2,1 mixed norm triggering joint sparsity across multichannels...
August 29, 2017: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28864905/measurement-of-protein-backbone-13-co-and-15-n-relaxation-dispersion-at-high-resolution
#17
Maxim Mayzel, Alexandra Ahlner, Patrik Lundström, Vladislav Y Orekhov
Peak overlap in crowded regions of two-dimensional spectra prevents characterization of dynamics for many sites of interest in globular and intrinsically disordered proteins. We present new three-dimensional pulse sequences for measurement of Carr-Purcell-Meiboom-Gill relaxation dispersions at backbone nitrogen and carbonyl positions. To alleviate increase in the measurement time associated with the additional spectral dimension, we use non-uniform sampling in combination with two distinct methods of spectrum reconstruction: compressed sensing and co-processing with multi-dimensional decomposition...
September 1, 2017: Journal of Biomolecular NMR
https://www.readbyqxmd.com/read/28863588/two-dimensional-grid-free-compressive-beamforming
#18
Yang Yang, Zhigang Chu, Zhongming Xu, Guoli Ping
Compressive beamforming realizes the direction-of-arrival (DOA) estimation and strength quantification of acoustic sources by solving an underdetermined system of equations relating microphone pressures to a source distribution via compressive sensing. The conventional method assumes DOAs of sources to lie on a grid. Its performance degrades due to basis mismatch when the assumption is not satisfied. To overcome this limitation for the measurement with plane microphone arrays, a two-dimensional grid-free compressive beamforming is developed...
August 2017: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/28858789/sparse-recovery-in-magnetic-resonance-imaging-with-a-markov-random-field-prior
#19
Marko Panic, Jan Aelterman, Vladimir Crnojevic, Aleksandra Pizurica
Recent research in compressed sensing of magnetic resonance imaging (CS-MRI) emphasizes the importance of modelling structured sparsity, either in the acquisition or in the reconstruction stages. Subband coefficients of typical images show certain structural patterns, which can be viewed in terms of fixed groups (like wavelet trees) or statistically (certain configurations are more likely than others). Wavelet tree models have already demonstrated excellent performance in MRI recovery from partial data. However, much less attention has been given in CS-MRI to modelling statistically spatial clustering of subband data, although the potentials of such models have been indicated...
August 24, 2017: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28855470/technical-aspects-of-contrast-enhanced-mr-angiography-current-status-and-new-applications
#20
Stephen J Riederer, Eric G Stinson, Paul T Weavers
This article is based on a presentation at the meeting of the Japanese Society of Magnetic Resonance in Medicine in September 2016. The purpose is to review the technical developments which have contributed to the current status of contrast-enhanced magnetic resonance angiography (CE-MRA) and to indicate related emerging areas of study. Technical developments include magnetic resonance imaging (MRI) physics-based innovations as well as improvements in MRI engineering. These have collectively addressed not only early issues of timing and venous suppression but more importantly have led to an improvement in spatiotemporal resolution of CE-MRA of more than two orders of magnitude compared to early results...
August 31, 2017: Magnetic Resonance in Medical Sciences: MRMS
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