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iterative reconstruction

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https://www.readbyqxmd.com/read/28717560/ultra-high-speed-digital-micro-mirror-device-based-ptychographic-iterative-engine-method
#1
Aihui Sun, Xiaoliang He, Yan Kong, Haoyang Cui, Xiaojun Song, Liang Xue, Shouyu Wang, Cheng Liu
To reduce the long data acquisition time of the common mechanical scanning based Ptychographic Iterative Engine (PIE) technique, the digital micro-mirror device (DMD) is used to form the fast scanning illumination on the sample. Since the transverse mechanical scanning in the common PIE is replaced by the on/off switching of the micro-mirrors, the data acquisition time can be reduced from more than 15 minutes to less than 20 seconds for recording 12 × 10 diffraction patterns to cover the same field of 147...
July 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28716683/trimmed-autocalibrating-k-space-estimation-based-on-structured-matrix-completion
#2
Mark Bydder, Stanislas Rapacchi, Olivier Girard, Maxime Guye, Jean-Philippe Ranjeva
PURPOSE: Parallel imaging allows the reconstruction of undersampled data from multiple coils. This provides a means to reject and regenerate corrupt data (e.g. from motion artefact). The purpose of this work is to approach this problem using the SAKE parallel imaging method. THEORY AND METHODS: Parallel imaging methods typically require calibration by fully sampling the center of k-space. This is a challenge in the presence of corrupted data, since the calibration data may be corrupted which leads to an errors-in-variables problem that cannot be solved by least squares or even iteratively reweighted least squares...
July 14, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28716682/air-mrf-accelerated-iterative-reconstruction-for-magnetic-resonance-fingerprinting
#3
Christopher C Cline, Xiao Chen, Boris Mailhe, Qiu Wang, Josef Pfeuffer, Mathias Nittka, Mark A Griswold, Peter Speier, Mariappan S Nadar
Existing approaches for reconstruction of multiparametric maps with magnetic resonance fingerprinting (MRF) are currently limited by their estimation accuracy and reconstruction time. We aimed to address these issues with a novel combination of iterative reconstruction, fingerprint compression, additional regularization, and accelerated dictionary search methods. The pipeline described here, accelerated iterative reconstruction for magnetic resonance fingerprinting (AIR-MRF), was evaluated with simulations as well as phantom and in vivo scans...
July 14, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28715327/joint-statistical-iterative-material-image-reconstruction-for-spectral-computed-tomography-using-a-semi-empirical-forward-model
#4
Korbinian Mechlem, Sebastian Ehn, Thorsten Sellerer, Eva Braig, Daniela Munzel, Franz Pfeiffer, Peter B Noel
By acquiring tomographic measurements with several distinct photon energy spectra, spectral computed tomography (spectral CT) is able to provide additional material-specific information compared to conventional CT. This information enables the generation of material selective images, which have found various applications in medical imaging. However, material decomposition typically leads to noise amplification and a degradation of the signal-to-noise ratio. This is still a fundamental problem of spectral CT, especially for low-dose medical applications...
July 13, 2017: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28712714/spinning-slithole-collimation-for-high-sensitivity-small-animal-spect-design-and-assessment-using-gate-simulation
#5
Hojjat Mahani, Gholamreza Raisali, Alireza Kamali-Asl, Mohammad Reza Ay
PURPOSE: While traditional collimations are widely used in preclinical SPECT imaging, they usually suffer from possessing a low system sensitivity leading to noisy images. In this study, we are aiming at introducing a novel collimator, the slithole, offering a superior resolution-sensitivity tradeoff for small animal SPECT. METHODS: The collimator was designed for a molecular SPECT scanner, the HiReSPECT. The slithole is a knife-edge narrow long aperture extended across long-axis of the camera's head...
July 13, 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28712701/impact-of-advanced-modeled-iterative-reconstruction-on-interreader-agreement-in-coronary-artery-measurements
#6
Tobias Gassenmaier, Isabel Distelmaier, Andreas M Weng, Thorsten A Bley, Thorsten Klink
OBJECTIVES: To evaluate the influence of advanced modeled iterative reconstruction (ADMIRE) on coronary artery computed tomography angiography (cCTA) measurements in comparison to filtered back projection (FBP). MATERIAL AND METHODS: Phantom scans and coronary CTA studies of 27 patients were acquired with a third generation dual-source CT scanner. Images were reconstructed using FBP and ADMIRE. Phantom measurements were used as reference standard. In patient studies, representative axial slices of each coronary artery segment without (n=308) and with coronary plaques (n=40) were assessed in identical positions for comparison of FBP and ADMIRE reconstructions...
July 1, 2017: European Journal of Radiology
https://www.readbyqxmd.com/read/28708166/low-photon-count-based-digital-holography-for-quadratic-phase-cryptography
#7
Inbarasan Muniraj, Changliang Guo, Ra'ed Malallah, James P Ryle, John J Healy, Byung-Geun Lee, John T Sheridan
Recently, the vulnerability of the linear canonical transform-based double random phase encryption system to attack has been demonstrated. To alleviate this, we present for the first time, to the best of our knowledge, a method for securing a two-dimensional scene using a quadratic phase encoding system operating in the photon-counted imaging (PCI) regime. Position-phase-shifting digital holography is applied to record the photon-limited encrypted complex samples. The reconstruction of the complex wavefront involves four sparse (undersampled) dataset intensity measurements (interferograms) at two different positions...
July 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28707531/third-version-of-vendor-specific-model-based-iterative-reconstruction-veo-3-0-evaluation-of-ct-image-quality-in-the-abdomen-using-new-noise-reduction-presets-and-varied-slice-optimization
#8
Morgan E Telesmanich, Corey T Jensen, Jose L Enriquez, Nicolaus A Wagner-Bartak, Xinming Liu, Ott Le, Wei Wei, Adam G Chandler, Eric P Tamm
OBJECTIVE: To qualitatively and quantitatively compare abdominal CT images reconstructed with a new version of model-based iterative reconstruction (Veo 3.0; GE Healthcare) utilizing varied presets of resolution preference, noise reduction, and slice optimization. METHODS: This retrospective study was approved by our IRB and was HIPAA compliant. The raw data from 30 consecutive patients who had undergone CT abdomen scanning were used to reconstruct 4 clinical presets of 3...
July 14, 2017: British Journal of Radiology
https://www.readbyqxmd.com/read/28707527/diagnostic-usefulness-of-low-dose-lumbar-multi-detector-ct-with-iterative-reconstruction-in-trauma-patients-a-comparison-with-standard-dose-ct
#9
Sun Hwa Lee, Seong Jong Yun, Dong Hyeon Kim, Hyeon Hwan Jo, Jae Gwang Song, Yong Sung Park
OBJECTIVE: To compare the image quality (IQ), radiation dose, and diagnostic reliability of standard-dose and low-dose lumbar spine (L-spine) multi-detector CT (SDCT and LDCT, respectively) with iterative reconstruction (IR) in trauma patients. METHODS: We retrospectively analyzed the data of 263 consecutive patients (male:female, 133:130; mean age, 44.3 years) who underwent SDCT (200-300 mAs; 120 kVp) with IR (n=126) or LDCT (80-150 mAs; 120 kVp) with IR (n=137) for suspected L-spine fractures between November 2015 and September 2016...
July 14, 2017: British Journal of Radiology
https://www.readbyqxmd.com/read/28703922/sensitivity-evaluation-and-selective-plane-imaging-geometry-for-x-ray-induced-luminescence-imaging
#10
Bryan P Quigley, Corey D Smith, Shih-Hsun Cheng, Jeffrey S Souris, Charles A Pelizzari, Chin-Tu Chen, Leu-Wei Lo, Chester S Reft, Rodney D Wiersma, Patrick J La Riviere
PURPOSE: X-ray induced luminescence (XIL) is a hybrid X-ray/optical imaging modality that employs nanophosphors that luminescence in response to X-ray irradiation. X-ray-activated phosphorescent nanoparticles have potential applications in radiation therapy as theranostics, nanodosimeters, or radiosensitizers. Extracting clinically relevant information from the luminescent signal requires the development of a robust imaging model that can determine nanophosphor distributions at depth in an optically scattering environment from surface radiance measurements...
July 13, 2017: Medical Physics
https://www.readbyqxmd.com/read/28702482/visualization-of-simulated-small-vessels-on-computed-tomography-using-a-model-based-iterative-reconstruction-technique
#11
Toru Higaki, Fuminari Tatsugami, Chikako Fujioka, Hiroaki Sakane, Yuko Nakamura, Yasutaka Baba, Makoto Iida, Kazuo Awai
This article describes a quantitative evaluation of visualizing small vessels using several image reconstruction methods in computed tomography. Simulated vessels with diameters of 1-6 mm made by 3D printer was scanned using 320-row detector computed tomography (CT). Hybrid iterative reconstruction (hybrid IR) and model-based iterative reconstruction (MBIR) were performed for the image reconstruction.
August 2017: Data in Brief
https://www.readbyqxmd.com/read/28697578/data-correlation-based-noise-level-estimation-for-cone-beam-projection-data
#12
Ti Bai, Hao Yan, Luo Ouyang, David Staub, Jing Wang, Xun Jia, Steve B Jiang, Xuanqin Mou
BACKGROUND: In regularized iterative reconstruction algorithms, the selection of regularization parameter depends on the noise level of cone beam projection data. OBJECTIVE: Our aim is to propose an algorithm to estimate the noise level of cone beam projection data. METHODS: We first derived the data correlation of cone beam projection data in the Fourier domain, based on which, the signal and the noise were decoupled. Then the noise was extracted and averaged for estimation...
July 7, 2017: Journal of X-ray Science and Technology
https://www.readbyqxmd.com/read/28697576/sparse-view-image-reconstruction-via-total-absolute-curvature-combining-total-variation-for-x-ray-computed-tomography
#13
Zhizhong Zheng, Ailong Cai, Lei Li, Bin Yan, Fulong Le, Linyuan Wang, Guoen Hu
Sparse-view imaging is a promising scanning approach which has fast scanning rate and low-radiation dose in X-ray computed tomography (CT). Conventional L1-norm based total variation (TV) has been widely used in image reconstruction since the advent of compressive sensing theory. However, with only the first order information of the image used, the TV often generates dissatisfactory image for some applications. As is widely known, image curvature is among the most important second order features of images and can potentially be applied in image reconstruction for quality improvement...
July 7, 2017: Journal of X-ray Science and Technology
https://www.readbyqxmd.com/read/28695497/comparison-of-ctac-and-prone-imaging-for-the-detection-of-coronary-artery-disease-using-czt-spect
#14
Shimpei Ito, Akihiro Endo, Taiji Okada, Taku Nakamura, Takashi Sugamori, Nobuyuki Takahashi, Hiroyuki Yoshitomi, Kazuaki Tanabe
BACKGROUND: Cadmium-zinc-telluride (CZT) cameras have improved the evaluation of patients with chest pain. However, inferior/inferolateral attenuation artifacts similar to those seen with conventional Anger cameras persist. We added prone acquisitions and CT attenuation correction (CTAC) to the standard supine image acquisition and analyzed the resulting examinations. METHODS AND RESULTS: Seventy-two patients referred for invasive coronary angiography (CAG), and who also underwent rest/stress myocardial perfusion imaging (MPI) on a CZT camera in the supine and prone positions plus CTAC imaging, to examine known or suspected CAD between April 2013 and March 2014 were included...
July 10, 2017: Annals of Nuclear Medicine
https://www.readbyqxmd.com/read/28695359/radiation-dose-reduction-for-ct-assessment-of-urolithiasis-using-iterative-reconstruction-a-prospective-intra-individual-study
#15
Annemarie M den Harder, Martin J Willemink, Pieter J van Doormaal, Frank J Wessels, M T W T Lock, Arnold M R Schilham, Ricardo P J Budde, Tim Leiner, Pim A de Jong
OBJECTIVE: To assess the performance of hybrid (HIR) and model-based iterative reconstruction (MIR) in patients with urolithiasis at reduced-dose computed tomography (CT). METHODS: Twenty patients scheduled for unenhanced abdominal CT for follow-up of urolithiasis were prospectively included. Routine dose acquisition was followed by three low-dose acquisitions at 40%, 60% and 80% reduced doses. All images were reconstructed with filtered back projection (FBP), HIR and MIR...
July 10, 2017: European Radiology
https://www.readbyqxmd.com/read/28692677/fux-sim-implementation-of-a-fast-universal-simulation-reconstruction-framework-for-x-ray-systems
#16
Monica Abella, Estefania Serrano, Javier Garcia-Blas, Ines García, Claudia de Molina, Jesus Carretero, Manuel Desco
The availability of digital X-ray detectors, together with advances in reconstruction algorithms, creates an opportunity for bringing 3D capabilities to conventional radiology systems. The downside is that reconstruction algorithms for non-standard acquisition protocols are generally based on iterative approaches that involve a high computational burden. The development of new flexible X-ray systems could benefit from computer simulations, which may enable performance to be checked before expensive real systems are implemented...
2017: PloS One
https://www.readbyqxmd.com/read/28689080/3d-reconstruction-of-the-magnetic-vector-potential-using-model-based-iterative-reconstruction
#17
K C Prabhat, K Aditya Mohan, Charudatta Phatak, Charles Bouman, Marc De Graef
Lorentz transmission electron microscopy (TEM) observations of magnetic nanoparticles contain information on the magnetic and electrostatic potentials. Vector field electron tomography (VFET) can be used to reconstruct electromagnetic potentials of the nanoparticles from their corresponding LTEM images. The VFET approach is based on the conventional filtered back projection approach to tomographic reconstructions and the availability of an incomplete set of measurements due to experimental limitations means that the reconstructed vector fields exhibit significant artifacts...
July 3, 2017: Ultramicroscopy
https://www.readbyqxmd.com/read/28688583/image-improvement-method-for-positron-emission-mammography
#18
Nikolai V Slavine, Stephen J Seiler, Roderick W McColl, Robert E Lenkinski
PURPOSE: To evaluate in clinical use a rapidly converging, efficient iterative deconvolution algorithm (RSEMD) for improving the quantitative accuracy of previously reconstructed breast images by a commercial positron emission mammography (PEM) scanner. MATERIALS AND METHODS: The RSEMD method was tested on imaging data from clinical Naviscan Flex Solo II PEM scanner. This method was applied to anthropomorphic like breast phantom data and patient breast images previously reconstructed with Naviscan software to determine improvements in image resolution, signal to noise ratio (SNR) and contrast to noise ratio (CNR)...
July 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28686810/self-calibrated-correlation-imaging-with-k-space-variant-correlation-functions
#19
Yu Li, Masoud Edalati, Xingfu Du, Hui Wang, Jie J Cao
PURPOSE: Correlation imaging is a previously developed high-speed MRI framework that converts parallel imaging reconstruction into the estimate of correlation functions. The presented work aims to demonstrate this framework can provide a speed gain over parallel imaging by estimating k-space variant correlation functions. METHODS: Because of Fourier encoding with gradients, outer k-space data contain higher spatial-frequency image components arising primarily from tissue boundaries...
July 7, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28685253/detection-and-quantitation-of-right-ventricular-reversible-perfusion-defects-by-stress-spect-myocardial-perfusion-imaging-a-proof-of-principle-study
#20
Ayman A Farag, Jack Heo, Lindsey Tauxe, Pradeep Bhambhvani, Guido Germano, Paul Kavanagh, Ami E Iskandrian, Fadi G Hage
BACKGROUND: In patients with right dominant coronary circulation, the right ventricular (RV) myocardium and the inferior region of the left ventricular (LV) myocardium share a common source of blood flow. We hypothesized that stress/rest SPECT myocardial perfusion imaging (MPI) could detect reversible perfusion defects in the RV in some patients with LV inferior wall perfusion abnormalities. MATERIAL AND METHODS: We identified 2 groups of patients with LV inferior wall perfusion defects (with or without defects in other regions of LV myocardium) from our database...
July 6, 2017: Journal of Nuclear Cardiology: Official Publication of the American Society of Nuclear Cardiology
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