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iterative model reconstruction

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https://www.readbyqxmd.com/read/28432820/the-impact-of-small-motion-on-the-visualization-of-coronary-vessels-and-lesions-in-cardiac-ct-a-simulation-study
#1
Francisco Contijoch, J Webster Stayman, Elliot R McVeigh
PURPOSE: Coronary x-ray computed tomography angiography (CCTA) is used to non-invasively assess coronary artery geometry and has, combined with computational modeling, demonstrated the potential to identify physiologically significant lesions. These measurements require robust and accurate coronary imaging and delineation of vessels in the presence of small motion. This simulation study characterizes the impact of small, uncorrected vessel drifts during data acquisition on the assessment of vessel intensity, diameter, and shape...
April 22, 2017: Medical Physics
https://www.readbyqxmd.com/read/28429371/design-of-a-short-non-uniform-acquisition-protocol-for-quantitative-analysis-in-dynamic-cardiac-spect-imaging-a-retrospective-123-i-mibg-animal-study
#2
Yunlong Zan, Yong Long, Kewei Chen, Biao Li, Qiu Huang, Grant T Gullberg
PURPOSE: Our previous works have found that quantitative analysis of (123) I-MIBG kinetics in the heart with dynamic single-photon emission computed tomography (SPECT) offers the potential to quantify the innervation integrity at an early stage of left ventricular hypertrophy. However, conventional protocols involving a long acquisition time for dynamic imaging reduce the animal survival rate and thus make longitudinal analysis difficult. The goal of this work was to develop a procedure to reduce the total acquisition time by selecting non-uniform acquisition times for projection views while maintaining the accuracy and precision of estimated physiologic parameters...
April 21, 2017: Medical Physics
https://www.readbyqxmd.com/read/28417170/reduced-dose-ct-with-model-based-iterative-reconstruction-compared-to-standard-dose-ct-of-the-chest-abdomen-and-pelvis-in-oncology-patients-intra-individual-comparison-study-on-image-quality-and-lesion-conspicuity
#3
Linda Nayeli Morimoto, Aya Kamaya, Isabelle Boulay-Coletta, Dominik Fleischmann, Lior Molvin, Lu Tian, George Fisher, Jia Wang, Jürgen K Willmann
PURPOSE: To compare image quality and lesion conspicuity of reduced dose (RD) CT with model-based iterative reconstruction (MBIR) compared to standard dose (SD) CT in patients undergoing oncological follow-up imaging. METHODS: Forty-four cancer patients who had a staging SD CT within 12 months were prospectively included to undergo a weight-based RD CT with MBIR. Radiation dose was recorded and tissue attenuation and image noise of four tissue types were measured...
April 17, 2017: Abdominal Radiology
https://www.readbyqxmd.com/read/28414380/iterative-reconstruction-of-scene-depth-with-fidelity-based-on-light-field-data
#4
Chang Liu, Jun Qiu, Songnian Zhao
Depth reconstruction from the light field, as a depth extracting approach, is a vibrant research field in computational imaging. In this paper, depth reconstruction from the light field was approached as an optimization problem by analyzing the forward and inverse models. The forward and inverse models present the connection between the light field and the depth of the scene. We proposed an iterative method for scene depth reconstruction with fidelity from 4D light field data. The objective function of the optimization problem entails three terms, of which the matching term is used as the fidelity term, while the gradient term and classification term constitute the penalty terms...
April 10, 2017: Applied Optics
https://www.readbyqxmd.com/read/28409258/impact-of-knowledge-based-iterative-model-reconstruction-on-myocardial-late-iodine-enhancement-in-computed-tomography-and-comparison-with-cardiac-magnetic-resonance
#5
Yuki Tanabe, Teruhito Kido, Akira Kurata, Naoki Fukuyama, Takahiro Yokoi, Tomoyuki Kido, Teruyoshi Uetani, Mani Vembar, Amar Dhanantwari, Shinichi Tokuyasu, Natsumi Yamashita, Teruhito Mochizuki
We evaluated the image quality and diagnostic performance of late iodine enhancement computed tomography (LIE-CT) with knowledge-based iterative model reconstruction (IMR) for the detection of myocardial infarction (MI) in comparison with late gadolinium enhancement magnetic resonance imaging (LGE-MRI). The study investigated 35 patients who underwent a comprehensive cardiac CT protocol and LGE-MRI for the assessment of coronary artery disease. The CT protocol consisted of stress dynamic myocardial CT perfusion, coronary CT angiography (CTA) and LIE-CT using 256-slice CT...
April 13, 2017: International Journal of Cardiovascular Imaging
https://www.readbyqxmd.com/read/28406049/evaluation-of-reduced-dose-ct-for-acute-non-traumatic-abdominal-pain-evaluation-of-diagnostic-accuracy-in-comparison-to-standard-dose-ct
#6
Ahmed E Othman, Malte Niklas Bongers, Dominik Zinsser, Christoph Schabel, Julian L Wichmann, Rami Arshid, Mike Notohamiprodjo, Konstantin Nikolaou, Fabian Bamberg
Background Patients with acute non-traumatic abdominal pain often undergo abdominal computed tomography (CT). However, abdominal CT is associated with high radiation exposure. Purpose To evaluate diagnostic performance of a reduced-dose 100 kVp CT protocol with advanced modeled iterative reconstruction as compared to a linearly blended 120 kVp protocol for assessment of acute, non-traumatic abdominal pain. Material and Methods Two radiologists assessed 100 kVp and linearly blended 120 kVp series of 112 consecutive patients with acute non-traumatic pain (onset < 48 h) regarding image quality, noise, and artifacts on a five-point Likert scale...
January 1, 2017: Acta Radiologica
https://www.readbyqxmd.com/read/28405477/influence-of-adaptive-statistical-iterative-reconstruction-algorithm-on-image-quality-in-coronary-computed-tomography-angiography
#7
Helle Precht, Jesper Thygesen, Oke Gerke, Kenneth Egstrup, Dag Waaler, Jess Lambrechtsen
BACKGROUND: Coronary computed tomography angiography (CCTA) requires high spatial and temporal resolution, increased low contrast resolution for the assessment of coronary artery stenosis, plaque detection, and/or non-coronary pathology. Therefore, new reconstruction algorithms, particularly iterative reconstruction (IR) techniques, have been developed in an attempt to improve image quality with no cost in radiation exposure. PURPOSE: To evaluate whether adaptive statistical iterative reconstruction (ASIR) enhances perceived image quality in CCTA compared to filtered back projection (FBP)...
December 2016: Acta Radiologica Open
https://www.readbyqxmd.com/read/28402129/consistency-of-renal-stone-volume-measurements-across-ct-scanner-model-and-reconstruction-algorithm-configurations
#8
Alice E Huang, Juan C Montoya, Maria Shiung, Shuai Leng, Cynthia H McCollough
OBJECTIVE: The objective of this prospective study is to evaluate the consistency of renal stone volume estimation using dual-energy CT across scanner model and reconstruction algorithm configurations. SUBJECTS AND METHODS: Patients underwent scanning with routine kidney stone composition protocols on both second- and third-generation dual-source CT scanners. Images were reconstructed using filtered back projection and iterative reconstruction (IR). In addition, a modified IR kernel on the third-generation CT scanner was evaluated...
April 12, 2017: AJR. American Journal of Roentgenology
https://www.readbyqxmd.com/read/28396126/improved-estimation-of-coronary-plaque-and-luminal-attenuation-using-a-vendor-specific-model-based-iterative-reconstruction-algorithm-in-contrast-enhanced-ct-coronary-angiography
#9
Yoshinori Funama, Daisuke Utsunomiya, Kenichiro Hirata, Katsuyuki Taguchi, Takeshi Nakaura, Seitaro Oda, Masafumi Kidoh, Hideaki Yuki, Yasuyuki Yamashita
RATIONALE AND OBJECTIVES: To investigate the stabilities of plaque attenuation and coronary lumen for different plaque types, stenotic degrees, lumen densities, and reconstruction methods using coronary vessel phantoms and the visualization of coronary plaques in clinical patients through coronary computed tomography (CT) angiography. MATERIALS AND METHODS: We performed 320-detector volume scanning of vessel tubes with stenosis and a tube without stenosis using three types of plaque CT numbers...
April 7, 2017: Academic Radiology
https://www.readbyqxmd.com/read/28390673/diagnostic-performance-of-256-row-detector-coronary-ct-angiography-in-patients-with-high-heart-rates-within-a-single-cardiac-cycle-a%C3%A2-preliminary-study
#10
J Liang, H Wang, L Xu, L Yang, L Dong, Z Fan, R Wang, Z Sun
AIM: To evaluate the image quality and diagnostic performance of coronary computed tomography angiography (CCTA) in patients with high heart rate within a single cardiac cycle using a 256-row detector CT system. MATERIALS AND METHODS: Eighty-four consecutive symptomatic patients (mean age 60.4±9.1 years, 52 men) with suspected coronary artery disease and heart rate ≥75 beats/min undergoing CCTA and invasive coronary angiography (ICA) were enrolled retrospectively...
April 5, 2017: Clinical Radiology
https://www.readbyqxmd.com/read/28387700/iterative-reconstruction-for-sparse-view-x-ray-ct-using-alpha-divergence-constrained-total-generalized-variation-minimization
#11
Shanzhou Niu, Jing Huang, Zhaoying Bian, Dong Zeng, Wufan Chen, Gaohang Yu, Zhengrong Liang, Jianhua Ma
BCKGROUND: Accurate statistical model of the measured projection data is essential for computed tomography (CT) image reconstruction. The transmission data can be described by a compound Poisson distribution upon an electronic noise background. However, such a statistical distribution is numerically intractable for image reconstruction. OBJECTIVE: Although the sinogram data is easily manipulated, it lacks a statistical description for image reconstruction. To address this problem, we present an alpha-divergence constrained total generalized variation (AD-TGV) method for sparse-view x-ray CT image reconstruction...
April 5, 2017: Journal of X-ray Science and Technology
https://www.readbyqxmd.com/read/28387436/2d-3d-reconstruction-of-the-distal-femur-using-statistical-shape-models-addressing-personalized-surgical-instruments-in-knee-arthroplasty-a-feasibility-analysis
#12
Pietro Cerveri, Costanza Sacco, Gianluca Olgiati, Alfonso Manzotti, Guido Baroni
BACKGROUND: Personalized surgical instruments (PSI) have gained success in the domain of total knee replacement, demonstrating clinical outcomes similar or even superior to both traditional and navigated surgeries. The key requirement for prototyping PSI is the availability of the digital bony surface. In this paper, we aim at verifying whether the 2D/3D reconstruction of the distal femur, based on statistical shape models (SSM), grants sufficient accuracy, especially in the condylar regions, to support a PSI technique...
April 7, 2017: International Journal of Medical Robotics + Computer Assisted Surgery: MRCAS
https://www.readbyqxmd.com/read/28382537/delayed-contrast-enhanced-computed-tomography-in-patients-with-known-or-suspected-cardiac-sarcoidosis-a-feasibility-study
#13
Tadao Aikawa, Noriko Oyama-Manabe, Masanao Naya, Hiroshi Ohira, Ayako Sugimoto, Ichizo Tsujino, Masahiko Obara, Osamu Manabe, Kohsuke Kudo, Hiroyuki Tsutsui, Nagara Tamaki
OBJECTIVES: To evaluate the diagnostic value of delayed contrast-enhanced computed tomography (DE-CT) for cardiac sarcoidosis (CS) in patients with or without implantable devices, including a quantitative comparison with late gadolinium enhancement cardiac magnetic resonance (LGE-CMR). METHODS: Twenty-four patients (mean age, 64 ± 9 years; 17 women) with known or suspected CS underwent retrospective electrocardiogram-gated DE-CT at 80 kV with knowledge-based iterative model reconstruction...
April 5, 2017: European Radiology
https://www.readbyqxmd.com/read/28380245/a-method-to-extract-image-noise-level-from-patient-images-in-ct
#14
Annelise Malkus, Timothy P Szczykutowicz
PURPOSE: Image quality in computed tomography (CT) is usually not quantified in real time from patient scans. Rather, phantom scans are employed to measure the contrast, noise, and spatial resolution properties of a given system. This approach, however, is not ideal because many factors are difficult to represent using phantoms like variations in patient size, composition, and position within the gantry. Several methods for measuring the noise found within patient scans have been proposed...
April 5, 2017: Medical Physics
https://www.readbyqxmd.com/read/28374080/impact-of-model-based-iterative-reconstruction-on-low-contrast-lesion-detection-and-image-quality-in-abdominal-ct-a-12-reader-based-comparative-phantom-study-with-filtered-back-projection-at-different-tube-voltages
#15
André Euler, Bram Stieltjes, Zsolt Szucs-Farkas, Reto Eichenberger, Clemens Reisinger, Anna Hirschmann, Caroline Zaehringer, Achim Kircher, Matthias Streif, Sabine Bucher, David Buergler, Luigia D Errico, Sebastién Kopp, Markus Wilhelm, Sebastian T Schindera
OBJECTIVES: To evaluate the impact of model-based iterative reconstruction (MBIR) on image quality and low-contrast lesion detection compared with filtered back projection (FBP) in abdominal computed tomography (CT) of simulated medium and large patients at different tube voltages. METHODS: A phantom with 45 hypoattenuating lesions was placed in two water containers and scanned at 70, 80, 100, and 120 kVp. The 120-kVp protocol served as reference, and the volume CT dose index (CTDIvol) was kept constant for all protocols...
April 3, 2017: European Radiology
https://www.readbyqxmd.com/read/28369941/a-model-based-iterative-reconstruction-algorithm-dira-using-patient-specific-tissue-classification-via-dect-for-improved-quantitative-ct-in-dose-planning
#16
Alexandr Malusek, Maria Magnussony, Michael Sandborg, Gudrun Alm Carlsson
PURPOSE: To develop and evaluate-in a proof-of-concept configuration-a novel iterative reconstruction algorithm (DIRA) for quantitative determination of elemental composition of patient tissues for application to brachytherapy with low energy (< 50 keV) photons and proton therapy. METHODS: DIRA was designed as a model-based iterative reconstruction algorithm, which uses filtered backprojection, automatic segmentation and multimaterial tissue decomposition. The evaluation was done for a phantom derived from the voxelized ICRP 110 male phantom...
March 30, 2017: Medical Physics
https://www.readbyqxmd.com/read/28367572/a-systematic-reconstruction-and-constraint-based-analysis-of-leishmania-donovani-metabolic-network-identification-of-potential-antileishmanial-drug-targets
#17
Mahesh Sharma, Naeem Shaikh, Shailendra Yadav, Sushma Singh, Prabha Garg
Visceral leishmaniasis, a lethal parasitic disease, is caused by the protozoan parasite Leishmania donovani. The absence of an effective vaccine, drug toxicity and parasite resistance necessitates the identification of novel drug targets. Reconstruction of genome-scale metabolic models and their simulation has been established as an important tool for systems-level understanding of a microorganism's metabolism. In this work, amalgamating the tools and techniques of computational systems biology with rigorous manual curation, a constraint-based metabolic model for Leishmania donovani BPK282A1 has been developed...
April 3, 2017: Molecular BioSystems
https://www.readbyqxmd.com/read/28365232/iterative-reconstructions-in-reduced-dose-ct-which-type-ensures-diagnostic-image-quality-in-young-oncology-patients
#18
Bastien Pauchard, Kai Higashigaito, Aicha Lamri-Senouci, Jean-Francois Knebel, Dominik Berthold, Francis Robert Verdun, Hatem Alkadhi, Sabine Schmidt
RATIONALE AND OBJECTIVES: To compare adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) algorithms for reduced-dose computed tomography (CT). MATERIALS AND METHODS: Forty-four young oncology patients (mean age 30 ± 9 years) were included. After routine thoraco-abdominal CT (dose 100%, average CTDIvol 9.1 ± 2.4 mGy, range 4.4-16.9 mGy), follow-up CT was acquired at 50% (average CTDIvol 4.5 ± 1.2 mGy, range 2...
March 29, 2017: Academic Radiology
https://www.readbyqxmd.com/read/28362638/task-driven-optimization-of-ct-tube-current-modulation-and-regularization-in-model-based-iterative-reconstruction
#19
Grace Jianan Gang, Jeffrey Siewerdsen, Joseph Stayman
Tube current modulation (TCM) is routinely adopted on diagnostic CT scanners for dose reduction. Conventional TCM strategies are generally designed for filtered-backprojection (FBP) reconstruction to satisfy simple image quality requirements based on noise. This work investigates TCM designs for model-based iterative reconstruction (MBIR) to achieve optimal imaging performance as determined by a task-based image quality metric. Additionally, regularization is an important aspect of MBIR that is jointly optimized with TCM, and includes both the regularization strength that controls overall smoothness as well as directional weights that permits control of the isotropy/anisotropy of the local noise and resolution properties...
March 31, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28361129/modeling-shift-variant-x-ray-focal-spot-blur-for-high-resolution-flat-panel-cone-beam-ct
#20
Steven Tilley, Wojciech Zbijewski, Jeffrey H Siewerdsen, J Webster Stayman
Flat-panel cone-beam CT (CBCT) has been applied clinically in a number of high-resolution applications. Increasing geometric magnification can potentially improve resolution, but also increases blur due to an extended x-ray focal-spot. We present a shift-variant focal-spot blur model and incorporate it into a model-based iterative-reconstruction algorithm. We apply this algorithm to simulation and CBCT test-bench data. In a trabecular bone simulation study, we find traditional reconstruction approaches without a blur model exhibit shift-variant resolution properties that depend greatly on the acquisition protocol (e...
July 2016: Conference Proceedings of International Conference on Image Formation in X-Ray Computed Tomography
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