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iterative model reconstruction

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https://www.readbyqxmd.com/read/29328098/demonstration-of-single-shot-digital-holography-using-a-bayesian-framework
#1
Casey J Pellizzari, Matthias T Banet, Mark F Spencer, Charles A Bouman
In this paper, we present experimental results for image reconstruction, with isoplanatic phase-error correction, from single-shot digital holography data. We demonstrate the utility of using a model-based iterative reconstruction (MBIR) algorithm to jointly compute the maximum a posteriori estimates of the phase errors and the real-valued object reflectance function. Specifically, we show that the MBIR algorithm is robust to noise and phase errors over a range of conditions.
January 1, 2018: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
https://www.readbyqxmd.com/read/29328048/a-biomechanical-modeling-guided-simultaneous-motion-estimation-and-image-reconstruction-technique-smeir-bio-for-4d-cbct-reconstruction
#2
Xiaokun Huang, You Zhang, Jing Wang
Reconstructing four-dimensional cone-beam computed tomography (4D-CBCT) images directly from respiratory phase-sorted traditional 3D-CBCT projections can capture target motion trajectory, reduce motion artifacts, and reduce imaging dose and time. However, the limited numbers of projections in each phase after phase-sorting decreases CBCT image quality under traditional reconstruction techniques. To address this problem, we developed a simultaneous motion estimation and image reconstruction (SMEIR) algorithm, an iterative method that can reconstruct higher quality 4D-CBCT images from limited projections using an inter-phase intensity-driven motion model...
January 12, 2018: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/29320863/evaluation-of-an-iterative-model-based-ct-reconstruction-algorithm-by-intra-patient-comparison-of-standard-and-ultra-low-dose-examinations
#3
Peter B Noël, Stephan Engels, Thomas Köhler, Daniela Muenzel, Daniela Franz, Michael Rasper, Ernst J Rummeny, Martin Dobritz, Alexander A Fingerle
Background The explosive growth of computer tomography (CT) has led to a growing public health concern about patient and population radiation dose. A recently introduced technique for dose reduction, which can be combined with tube-current modulation, over-beam reduction, and organ-specific dose reduction, is iterative reconstruction (IR). Purpose To evaluate the quality, at different radiation dose levels, of three reconstruction algorithms for diagnostics of patients with proven liver metastases under tumor follow-up...
January 1, 2018: Acta Radiologica
https://www.readbyqxmd.com/read/29312867/quantitative-assessment-of-nonsolid-pulmonary-nodule-volume-with-computed-tomography-in-a-phantom-study
#4
Marios A Gavrielides, Benjamin P Berman, Mark Supanich, Kurt Schultz, Qin Li, Nicholas Petrick, Rongping Zeng, Jenifer Siegelman
Background: To assess the volumetric measurement of small (≤1 cm) nonsolid nodules with computed tomography (CT), focusing on the interaction of state of the art iterative reconstruction (IR) methods and dose with nodule densities, sizes, and shapes. Methods: Twelve synthetic nodules [5 and 10 mm in diameter, densities of -800, -630 and -10 Hounsfield units (HU), spherical and spiculated shapes] were scanned within an anthropomorphic phantom. Dose [computed tomography scan dose index (CTDIvol)] ranged from standard (4...
December 2017: Quantitative Imaging in Medicine and Surgery
https://www.readbyqxmd.com/read/29302810/fast-gpu-based-monte-carlo-code-for-spect-ct-reconstructions-generates-improved-177lu-images
#5
T Rydén, J Heydorn Lagerlöf, J Hemmingsson, I Marin, J Svensson, M Båth, P Gjertsson, P Bernhardt
BACKGROUND: Full Monte Carlo (MC)-based SPECT reconstructions have a strong potential for correcting for image degrading factors, but the reconstruction times are long. The objective of this study was to develop a highly parallel Monte Carlo code for fast, ordered subset expectation maximum (OSEM) reconstructions of SPECT/CT images. The MC code was written in the Compute Unified Device Architecture language for a computer with four graphics processing units (GPUs) (GeForce GTX Titan X, Nvidia, USA)...
January 4, 2018: EJNMMI Physics
https://www.readbyqxmd.com/read/29287661/time-dependent-behavior-of-porcine-periodontal-ligament-a-combined-experimental-numeric-in-vitro-study
#6
Thomas Johannes Knaup, Cornelius Dirk, Susanne Reimann, Ludger Keilig, Meike Eschbach, Heike Korbmacher-Steiner, Christoph Bourauel
INTRODUCTION: The aim of this study was to analyze the time-dependent in-vitro behavior of the periodontal ligament (PDL) by determining the material parameters using specimens of porcine jawbone. Time-dependent material parameters to be determined were expected to complement the results from earlier biomechanical studies. METHODS: Five mandibular deciduous porcine premolars were analyzed in a combined experimental-numeric study. After selecting suitable specimens (excluding root resorption) and preparing the measurement system, the specimens were deflected by a distance of 0...
January 2018: American Journal of Orthodontics and Dentofacial Orthopedics
https://www.readbyqxmd.com/read/29261354/prospective-comparison-of-standard-versus-low-radiation-dose-ct-enterography-for-the-quantitative-assessment-of-crohn-disease
#7
Greg Rosenfeld, Jacqueline Brown, Patrick M Vos, Jonathon Leipsic, Robert Enns, Brian Bressler
OBJECTIVE: CT enterography (CTE) is sensitive and specific for active inflammatory changes of Crohn disease (CD), but its use has been limited by exposure to ionizing radiation. The objective of this study is to show the noninferiority of a model-based iterative reconstruction (MBIR) technique using lower radiation doses compared with standard-dose CTE in the assessment of CD. SUBJECTS AND METHODS: Patients referred to a hospital radiology department for CTE for the evaluation of CD underwent both a standard examination (used to generate filtered back-projection and adaptive statistical iterative reconstruction [ASIR] images) and low-dose MBIR CTE performed in a random sequence on the same day...
December 20, 2017: AJR. American Journal of Roentgenology
https://www.readbyqxmd.com/read/29249576/low-tube-voltage-and-iterative-model-reconstruction-in-follow-up-ct-angiography-after-thoracic-endovascular-aortic-repair-ultra-low-radiation-exposure-and-contrast-medium-dose
#8
Ping Hou, Xiangnan Feng, Jie Liu, Xiaopeng Wang, Yaojun Jiang, Leigang Dong, Jianbo Gao
RATIONALE AND OBJECTIVES: This study aimed to investigate the feasibility of reducing radiation exposure and contrast medium (CM) dose in follow-up computed tomography angiography (CTA) after thoracic endovascular aortic repair (TEVAR) using low tube voltage and knowledge-based iterative model reconstruction (IMR). MATERIALS AND METHODS: Thirty-six patients that required follow-up CTA after TEVAR were included in this intra-individual study. The conventional protocol with standard tube voltage of 120 kVp and CM volume of 70 mL was applied in the first follow-up CTA of all the patients (control group A)...
December 14, 2017: Academic Radiology
https://www.readbyqxmd.com/read/29247300/monte-carlo-based-quantitative-pinhole-spect-reconstruction-using-a-ray-tracing-back-projector
#9
Mikael Peterson, Johan Gustafsson, Michael Ljungberg
BACKGROUND: Monte Carlo simulations provide accurate models of nuclear medicine imaging systems as they can properly account for the full physics of photon transport. The accuracy of the model included in the maximum-likelihood-expectation-maximization (ML-EM) reconstruction limits the overall accuracy of the reconstruction results. In this paper, we present a Monte Carlo-based ML-EM reconstruction method for pinhole single-photon emission computed tomography (SPECT) that has been incorporated into the SIMIND Monte Carlo program...
December 15, 2017: EJNMMI Physics
https://www.readbyqxmd.com/read/29231760/the-impact-of-dose-reduction-in-quantitative-kinematic-ct-of-ankle-joints-using-a-full-model-based-iterative-reconstruction-algorithm-a-cadaveric-study
#10
Charles Lombard, Alban Gervaise, Nicolas Villani, Mathias Louis, Ariane Raymond, Alain Blum, Pedro Augusto Gondim Teixeira
OBJECTIVE: The objective of our study was to evaluate the quality and reproducibility of semiautomatic measurements of the ankle in low-dose kinematic CT studies using a full model-based iterative reconstruction (MBIR). MATERIALS AND METHODS: Kinematic CT was performed in five cadaveric ankles at three acquisition dose levels: standard dose (1020 mGy × cm), low dose (10% of the standard dose), and ultra-low-dose (1.5% of the standard dose). All images were reconstructed using a full MBIR algorithm...
December 12, 2017: AJR. American Journal of Roentgenology
https://www.readbyqxmd.com/read/29231758/dose-reduction-with-dedicated-ct-metal-artifact-reduction-algorithm-ct-phantom-study
#11
Naveen Subhas, Camilla P Pursyko, Joshua M Polster, Nancy A Obuchowski, Andrew N Primak, Frank F Dong, Brian R Herts
OBJECTIVE: The objective of this study was to compare reader accuracy detecting lesions near hardware in a CT phantom model at different radiation exposures using an advanced metal artifact reduction (MAR) algorithm and standard filtered back projection (FBP) techniques and to determine if radiation exposure could be decreased using MAR without compromising lesion detectability. MATERIALS AND METHODS: A CT phantom manufactured with spherical lesions of various sizes (10-20 mm) and attenuations (20-50 HU) embedded around cobalt-chromium spheres attached to titanium rods, simulating an arthroplasty, was scanned on a single CT scanner (FLASH, Siemens Healthcare) at 140 kVp and 0...
December 12, 2017: AJR. American Journal of Roentgenology
https://www.readbyqxmd.com/read/29228285/matrix-factorization-based-data-fusion-for-the-prediction-of-lncrna-disease-associations
#12
Guangyuan Fu, Jun Wang, Carlotta Domeniconi, Guoxian Yu
Motivation: Long non-coding RNAs (lncRNAs) play crucial roles in complex disease diagnosis, prognosis, prevention, and treatment, but only a small portion of lncRNA-disease associations have been experimentally verified. Various computational models have been proposed to identify lncRNA-disease associations by integrating heterogeneous data sources. However, existing models generally ignore the intrinsic structure of data sources or treat them as equally relevant, while they may not be...
December 7, 2017: Bioinformatics
https://www.readbyqxmd.com/read/29218827/computational-study-of-estimating-3d-trabecular-bone-microstructure-for-the-volume-of-interest-from-ct-scan-data
#13
Jung Jin Kim, Jimin Nam, In Gwun Jang
Inspired by the self-optimizing capabilities of bone, a new concept of bone microstructure reconstruction has been recently introduced using 2D synthetic skeletal images. As a preliminary clinical study, this paper proposes a topology optimization-based method that can estimate 3D trabecular bone microstructure for the volume of interest (VOI) from 3D computed tomography (CT) scan data with enhanced computational efficiency and phenomenological accuracy. For this purpose, a localized finite element (FE) model is constructed by segmenting a target bone from CT scan data and determining the physiological local loads for the VOI...
December 7, 2017: International Journal for Numerical Methods in Biomedical Engineering
https://www.readbyqxmd.com/read/29214631/system-matrix-computation-vs-storage-on-gpu-a-comparative-study-in-cone-beam-ct
#14
Dmitri Matenine, Geoffroi Côté, Julia Mascolo-Fortin, Yves Goussard, Philippe Després
PURPOSE: Iterative reconstruction algorithms in computed tomography (CT) require a fast method for computing the intersection distances between the trajectories of photons and the object, also called ray-tracing or system matrix computation. This work focused on the thin-ray model and is aimed at comparing different system matrix handling strategies using graphical processing units (GPUs). METHODS: In this work, the system matrix is modeled by thin rays intersecting a regular grid of box-shaped voxels, known to be an accurate representation of the forward projection operator in CT...
December 6, 2017: Medical Physics
https://www.readbyqxmd.com/read/29205378/cardiac-gated-parametric-images-from-82-rb-pet-from-dynamic-frames-and-direct-4d-reconstruction
#15
Mary Germino, Richard E Carson
PURPOSE: Cardiac perfusion PET data can be reconstructed as a dynamic sequence and kinetic modeling performed to quantify myocardial blood flow, or reconstructed as static gated images to quantify function. Parametric images from dynamic PET are conventionally not gated, to allow use of all events with lower noise. An alternative method for dynamic PET is to incorporate the kinetic model into the reconstruction algorithm itself, bypassing the generation of a time series of emission images and directly producing parametric images...
December 5, 2017: Medical Physics
https://www.readbyqxmd.com/read/29191684/model-based-iterative-reconstruction-in-low-radiation-dose-computed-tomography-colonography-preoperative-assessment-in-patients-with-colorectal-cancer
#16
Narumi Taguchi, Seitaro Oda, Masanori Imuta, Sadahiro Yamamura, Takeshi Nakaura, Daisuke Utsunomiya, Masafumi Kidoh, Yasunori Nagayama, Hideaki Yuki, Kenichiro Hirata, Yuji Iyama, Yoshinori Funama, Hideo Baba, Yasuyuki Yamashita
RATIONALE AND OBJECTIVES: To assess the effect of model-based iterative reconstruction (MBIR) on image quality and diagnostic performance of low-radiation-dose computed tomography colonography (CTC) in the preoperative assessment of colorectal cancer. MATERIALS AND METHODS: This study included 30 patients with colorectal cancer referred for surgical treatment. All patients underwent CTC with a standard dose (SD) protocol in the supine position and a low-dose (LD; radiation dose reduction of approximately 85%) protocol in the prone position...
November 27, 2017: Academic Radiology
https://www.readbyqxmd.com/read/29190575/dictionary-based-fiber-orientation-estimation-with-improved-spatial-consistency
#17
Chuyang Ye, Jerry L Prince
Diffusion magnetic resonance imaging (dMRI) has enabled in vivo investigation of white matter tracts. Fiber orientation (FO) estimation is a key step in tract reconstruction and has been a popular research topic in dMRI analysis. In particular, the sparsity assumption has been used in conjunction with a dictionary-based framework to achieve reliable FO estimation with a reduced number of gradient directions. Because image noise can have a deleterious effect on the accuracy of FO estimation, previous works have incorporated spatial consistency of FOs in the dictionary-based framework to improve the estimation...
November 23, 2017: Medical Image Analysis
https://www.readbyqxmd.com/read/29184659/multi-modal-imaging-model-based-tracking-and-mixed-reality-visualisation-for-orthopaedic-surgery
#18
Sing Chun Lee, Bernhard Fuerst, Keisuke Tateno, Alex Johnson, Javad Fotouhi, Greg Osgood, Federico Tombari, Nassir Navab
Orthopaedic surgeons are still following the decades old workflow of using dozens of two-dimensional fluoroscopic images to drill through complex 3D structures, e.g. pelvis. This Letter presents a mixed reality support system, which incorporates multi-modal data fusion and model-based surgical tool tracking for creating a mixed reality environment supporting screw placement in orthopaedic surgery. A red-green-blue-depth camera is rigidly attached to a mobile C-arm and is calibrated to the cone-beam computed tomography (CBCT) imaging space via iterative closest point algorithm...
October 2017: Healthcare Technology Letters
https://www.readbyqxmd.com/read/29175383/an-efficient-algorithm-for-dynamic-mri-using-low-rank-and-total-variation-regularizations
#19
Jiawen Yao, Zheng Xu, Xiaolei Huang, Junzhou Huang
In this paper, we propose an efficient algorithm for dynamic magnetic resonance (MR) image reconstruction. With the total variation (TV) and the nuclear norm (NN) regularization, the TVNNR model can utilize both spatial and temporal redundancy in dynamic MR images. Such prior knowledge can help model dynamic MRI data significantly better than a low-rank or a sparse model alone. However, it is very challenging to efficiently minimize the energy function due to the non-smoothness and non-separability of both TV and NN terms...
November 17, 2017: Medical Image Analysis
https://www.readbyqxmd.com/read/29172865/mammoth-a-new-database-for-curated-mathematical-models-of-biomolecular-systems
#20
Fedor Kazantsev, Ilya Akberdin, Sergey Lashin, Natalia Ree, Vladimir Timonov, Alexander Ratushny, Tamara Khlebodarova, Vitaly Likhoshvai
MOTIVATION: Living systems have a complex hierarchical organization that can be viewed as a set of dynamically interacting subsystems. Thus, to simulate the internal nature and dynamics of the entire biological system, we should use the iterative way for a model reconstruction, which is a consistent composition and combination of its elementary subsystems. In accordance with this bottom-up approach, we have developed the MAthematical Models of bioMOlecular sysTems (MAMMOTh) tool that consists of the database containing manually curated MAMMOTh fitted to the experimental data and a software tool that provides their further integration...
November 3, 2017: Journal of Bioinformatics and Computational Biology
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