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Compressed sensing

Saiprasad Ravishankar, Brian Moore, Raj Nadakuditi, Jeffrey Fessler
Sparsity-based approaches have been popular in many applications in image processing and imaging. Compressed sensing exploits the sparsity of images in a transform domain or dictionary to improve image recovery from undersampled measurements. In the context of inverse problems in dynamic imaging, recent research has demonstrated the promise of sparsity and low-rank techniques. For example, the patches of the underlying data are modeled as sparse in an adaptive dictionary domain, and the resulting image and dictionary estimation from undersampled measurements is called dictionary-blind compressed sensing, or the dynamic image sequence is modeled as a sum of low-rank and sparse (in some transform domain) components (L+S model) that are estimated from limited measurements...
January 10, 2017: IEEE Transactions on Medical Imaging
Neil M Kumar, Cesar de Cesar Netto, Lew C Schon, Jan Fritz
OBJECTIVES: Long echo train length (ETL) is an often recommended but unproven technique to decrease metal artifacts on magnetic resonance imaging (MRI) scans. Therefore, we quantitatively and qualitatively assessed the effects of ETL on metal artifact on MRI scans using a cobalt-chromium-containing arthroplasty implant system. MATERIALS AND METHODS: Using a total ankle arthroplasty system implanted into a human cadaver ankle and a clinical 1.5 T MRI system, turbo spin echo (TSE) pulse sequences were acquired with ETL ranging from 3 to 23 and receiver bandwidth (BW) from 100 to 750 Hz/pixel, whereas effective echo time and spatial resolution were controlled...
January 9, 2017: Investigative Radiology
Ho Lee, Benjamin Fahimian, Lei Xing
This paper proposes a binary moving-blocker (BMB)-based technique for scatter correction in cone-beam computed tomography (CBCT). In concept, a beam blocker consisting of lead strips, mounted in front of the x-ray tube, moves rapidly in and out of the beam during a single gantry rotation. The projections are acquired in alternating phases of blocked and unblocked cone beams, where the blocked phase results in a stripe pattern in the width direction. To derive the scatter map from the blocked projections, one-dimensional B-Spline interpolation/extrapolation is applied by using the detected information in the shaded regions...
January 12, 2017: Physics in Medicine and Biology
Ludwig Mach
In some cases our sensory organs are no longer capable of rendering processes in the external world perceptible to us. Their inadequacy expresses itself, for example, in phenomena that involve the kind of expansion of space and time in which the conditions for summary perception are no longer at all present. The resources that aid our immediate sense perception in these circumstances will thus be charged with the task of expanding or diminishing space and time to the extent that the contiguity and succession of events is comprehensible to us...
December 2016: Science in Context
Eugene Milshteyn, Cornelius von Morze, Galen D Reed, Hong Shang, Peter J Shin, Zihan Zhu, Hsin-Yu Chen, Robert Bok, Andrei Goga, John Kurhanewicz, Peder E Z Larson, Daniel B Vigneron
The goal of this project was to develop and apply techniques for T2 mapping and 3D high resolution (1.5 mm isotropic; 0.003 cm(3)) (13)C imaging of hyperpolarized (HP) probes [1-(13)C]lactate, [1-(13)C]pyruvate, [2-(13)C]pyruvate, and [(13)C,(15)N2]urea in vivo. A specialized 2D bSSFP sequence was implemented on a clinical 3T scanner and used to obtain the first high resolution T2 maps of these different hyperpolarized compounds in both rats and tumor-bearing mice. These maps were first used to optimize timings for highest SNR for single time-point 3D bSSFP acquisitions with a 1...
January 7, 2017: Magnetic Resonance Imaging
Dong Xie, Lixiang Li, Haipeng Peng, Yixian Yang
In a general (k, n) scalable secret image sharing (SSIS) scheme, the secret image is shared by n participants and any k or more than k participants have the ability to reconstruct it. The scalability means that the amount of information in the reconstructed image scales in proportion to the number of the participants. In most existing SSIS schemes, the size of each image shadow is relatively large and the dealer does not has a flexible control strategy to adjust it to meet the demand of differen applications...
2017: PloS One
Toby Sanders, Anne Gelb, Rodrigo B Platte, Ilke Arslan, Kai Landskron
Over the last decade or so, reconstruction methods using ℓ1 regularization, often categorized as compressed sensing (CS) algorithms, have significantly improved the capabilities of high fidelity imaging in electron tomography. The most popular ℓ1 regularization approach within electron tomography has been total variation (TV) regularization. In addition to reducing unwanted noise, TV regularization encourages a piecewise constant solution with sparse boundary regions. In this paper we propose an alternative ℓ1 regularization approach for electron tomography based on higher order total variation (HOTV)...
January 3, 2017: Ultramicroscopy
Steve J A Majerus, Paul C Fletter, Elizabeth K Ferry, Hui Zhu, Kenneth J Gustafson, Margot S Damaser
AIMS: Managing bladder pressure in patients with neurogenic bladders is needed to improve rehabilitation options, avoid upper tract damage, incontinence, and their associated co-morbidities and mortality. Current methods of determining bladder contractions are not amenable to chronic or ambulatory settings. In this study we evaluated detection of bladder contractions using a novel piezoelectric catheter-free pressure sensor placed in a suburothelial bladder location in animals. METHODS: Wired prototypes of the pressure monitor were implanted into 2 nonsurvival (feline and canine) and one 13-day survival (canine) animal...
2017: PloS One
N Pavillon, N I Smith
We present a measurement and reconstruction method for laser-scanning microscopy based on compressed sensing, which enables significantly higher frame rates and reduced photobleaching. The image reconstruction accuracy is ensured by including a model of the physical imaging process into the compressed sensing reconstruction procedure. We demonstrate its applicability to unmodified commercial confocal fluorescence microscopy systems and for Raman imaging, showing a potential data reduction of 10-15 times, which directly leads to improvements in acquisition speed, or reduction of photobleaching, without significant loss of spatial resolution...
December 26, 2016: Optics Express
Yaniv Oiknine, Isaac August, Dan G Blumberg, Adrian Stern
We present a new fast compressive spectroscopic technique based on the resonance spectrometric mechanism. This technique uses an appropriately designed Fabry-Perot resonator and a photo-sensor in order to acquire different multiplexed spectral modulations, from which the original signal is reconstructed using a compressive sensing reconstruction algorithm. We present experimental results that demonstrate the acquisition of hundreds of spectral bands with a compression ratio of about 1:13.
January 1, 2017: Optics Letters
Jaewook Shin, Bryan T Bosworth, Mark A Foster
We demonstrate imaging using a multi-core fiber with a scattering distal tip and compressed sensing signal acquisition. We illuminate objects with randomly structured speckle patterns generated by a coherent light source separately coupled through each fiber core to a ground glass diffuser at the distal end. Using the characterized speckle patterns and the total light collected from the object, we computationally recover pixelation-free object images with up to a seven times higher space-bandwidth product than the number of cores...
January 1, 2017: Optics Letters
M Nakano, A Haga, J Kotoku, T Magome, Y Masutani, S Hanaoka, K Nakagawa
PURPOSE: The purpose of this study is to propose a new concept of four-dimensional (4D) cone-beam CT (CBCT) reconstruction for non-periodic organ motion using the Time-ordered Chain Graph Model (TCGM), and to compare the reconstructed results with the previously proposed methods, the total variation-based compressed sensing (TVCS) and prior-image constrained compressed sensing (PICCS). METHODS: CBCT reconstruction method introduced in this study consisted of maximum a posteriori (MAP) iterative reconstruction combined with a regularization term derived from a concept of TCGM, which includes a constraint coming from the images of neighbouring time-phases...
June 2016: Medical Physics
B Jiang, H Gao
PURPOSE: Accelerated dynamic MRI is important for MRI guided radiotherapy. Inspired by compressive sensing (CS), sub-Nyquist dynamic MRI has been an active research area, i.e., sparse sampling in k-t space for accelerated dynamic MRI. This work is to investigate sub-Nyquist dynamic MRI via a previously developed CS model, namely Prior Rank, Intensity and Sparsity Model (PRISM). METHODS: The proposed method utilizes PRISM with rank minimization and incoherent sampling patterns for sub-Nyquist reconstruction...
June 2016: Medical Physics
A Haga, T Magome, M Nakano, J Kotoku, K Nakagawa
PURPOSE: Cone-beam CT (CBCT) has become an integral part of online patient setup in an image-guided radiation therapy (IGRT). In addition, the utility of CBCT for dose calculation has actively been investigated. However, the limited size of field-of-view (FOV) and resulted CBCT image with a lack of peripheral area of patient body prevents the reliability of dose calculation. In this study, we aim to develop an FOV expanded CBCT in IGRT system to allow the dose calculation. METHODS: Three lung cancer patients were selected in this study...
June 2016: Medical Physics
K Li, P Yang, M Cathey, J Tang, H Rowley, P Turski, V Prabhakaran, C Strother, G-H Chen
PURPOSE: A prospective clinical study was conducted to assess whether sub-mSv cerebral CT perfusion (CTP) imaging can be achieved using the Prior Image Constrained Compressed Sensing (PICSS) reconstruction algorithm. METHODS: Following a standard dose (SD) CTP acquisition, 31 patients (median age, 62 years; 15 M/16 F; median BMI, 27) underwent an additional reduced dose (RD) CTP acquisition at 20% of the standard dose level. Several algorithms (PICCS, ASIR, and FBP) were used to reconstruct CTP source images of the RD series...
June 2016: Medical Physics
R Martin, M Ahmad, T Pan
PURPOSE: 4D CBCT can allow evaluation of tumor motion immediately prior to radiation therapy, but suffers from heavy artifacts that limit its ability to track tumors. Various iterative and compressed sensing reconstructions have been proposed to reduce these artifacts, but are costly time-wise and can degrade the image quality of bony anatomy for alignment with regularization. We have previously proposed an iterative volume of interest (I4D VOI) method which minimizes reconstruction time and maintains image quality of bony anatomy by focusing a 4D reconstruction within a VOI...
June 2016: Medical Physics
J M Slagowski, Dap Dunkerley
PURPOSE: To obtain ECG-gated CT images from truncated projection data acquired with a C-arm based inverse geometry fluoroscopy system, for the purpose of cardiac chamber mapping in interventional procedures. METHODS: Scanning-beam digital x-ray (SBDX) is an inverse geometry fluoroscopy system with a scanned multisource x-ray tube and a photon-counting detector mounted to a C-arm. In the proposed method, SBDX short-scan rotational acquisition is performed followed by inverse geometry CT (IGCT) reconstruction and segmentation of contrast-enhanced objects...
June 2016: Medical Physics
J Li, H Zhang, P Wang
PURPOSE: Cone-beam (CB) computed tomography (CT) is used for image guidance during radiotherapy treatment delivery. Conventional Feldkamp and compressed sensing (CS) based CBCT recon-struction techniques are compared for image registration. This study is to evaluate the image registration accuracy of conventional and CS CBCT for head-and-neck (HN) patients. METHODS: Ten HN patients with oropharyngeal tumors were retrospectively selected. Each HN patient had one planning CT (CTP) and three CBCTs were acquired during an adaptive radiotherapy proto-col...
June 2016: Medical Physics
E Yip, J Yun, K Wachowicz, Z Gabos, S Rathee, B Fallone
PURPOSE: Prior Data Assisted Compressed Sensing (PDACS) is a partial k-space acquisition and reconstruction method for mobile tumour (i.e. lung) tracking using on-line MRI in radiotherapy. PDACS partially relies on prior data acquired at the beginning of dynamic scans, and is therefore susceptible to artifacts in longer duration scan due to slow drifts in MR signal. A novel sliding window strategy is presented to mitigate this effect. METHODS: MRI acceleration is simulated by retrospective removal of data from the fully sampled sets...
June 2016: Medical Physics
B Li, Z Tian, L Zhou, S Jiang, X Jia
PURPOSE: While compressed sensing-based cone-beam CT (CBCT) iterative reconstruction techniques have demonstrated tremendous capability of reconstructing high-quality images from undersampled noisy data, its long computation time still hinders wide application in routine clinic. The purpose of this study is to develop a reconstruction framework that employs modern consensus optimization techniques to achieve CBCT reconstruction on a multi-GPU platform for improved computational efficiency...
June 2016: Medical Physics
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