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iterative model reconstruction

Caleb J Bashor, James J Collins
Engineering synthetic gene regulatory circuits proceeds through iterative cycles of design, building, and testing. Initial circuit designs must rely on often-incomplete models of regulation established by fields of reductive inquiry-biochemistry and molecular and systems biology. As differences in designed and experimentally observed circuit behavior are inevitably encountered, investigated, and resolved, each turn of the engineering cycle can force a resynthesis in understanding of natural network function...
March 16, 2018: Annual Review of Biophysics
Katsuyuki Taguchi, Toshihide Itoh, Matthew K Fuld, Eric Fournie, Okkyun Lee, Kyo Noguchi
OBJECTIVES: A novel imaging technique ("X-map") has been developed to identify acute ischemic lesions for stroke patients using non-contrast-enhanced dual-energy computed tomography (NE-DE-CT). Using the 3-material decomposition technique, the original X-map ("X-map 1.0") eliminates fat and bone from the images, suppresses the gray matter (GM)-white matter (WM) tissue contrast, and makes signals of edema induced by severe ischemia easier to detect. The aim of this study was to address the following 2 problems with the X-map 1...
March 14, 2018: Investigative Radiology
John W Garrett, Yinsheng Li, Ke Li, Guang-Hong Chen
PURPOSE: Digital breast tomosynthesis (DBT) has been shown to somewhat alleviate the breast tissue overlapping issues of two dimensional (2D) mammography.However, the improvement in current DBT systems over mammography is still limited.Statistical image reconstruction (SIR) methods have the potential to reduce through-plane artifacts in DBT, and thus may be used to further reduce anatomical clutter. The purpose of this work was to study the impact of SIR on anatomical clutter in the reconstructed DBT image volumes...
March 15, 2018: Medical Physics
Yan Wu, Yaojun Jiang, Xueli Han, Mingyue Wang, Jianbo Gao
Background: To investigate the repeatability and accuracy of quantitative CT (QCT) measurement of bone mineral density (BMD) by low-mAs using iterative model reconstruction (IMR) technique based on phantom model. Methods: European spine phantom (ESP) was selected and measured on the Philips Brilliance iCT Elite FHD machine for 10 times. Data were transmitted to the QCT PRO workstation to measure BMD (mg/cm3 ) of the ESP (L1, L2, L3). Scanning method: the voltage of X-ray tube is 120 kV, the electric current of X-ray tube output in five respective groups A-E were: 20, 30, 40, 50 and 60 mAs...
February 2018: Quantitative Imaging in Medicine and Surgery
A P Konijnenberg, W M J Coene, H P Urbach
A noise-robust extension of iterative phase retrieval algorithms that does not need to assume a noise model is proposed. It works by adapting the intensity constraints using the reconstructed object. Using a proof-of-principle ptychographic experiment with visible light and a spatial light modulator to create an object, the proposed method is tested and it compares favorably to the Extended Ptychographic Iterative Engine (ePIE) with reduced step size. The method is general, so it can also be applied to other iterative reconstruction schemes such as phase retrieval using focus variation...
March 5, 2018: Optics Express
Adrien Besson, Dimitris Perdios, Florian Martinez, Zhouye Chen, Rafael E Carrillo, Marcel Arditi, Yves Wiaux, Jean-Philippe Thiran
Conventional ultrasound (US) image reconstruction methods rely on delay-and-sum (DAS) beamforming, which is a relatively poor solution to the image reconstruction problem. An alternative to DAS consists in using iterative techniques, which require both an accurate measurement model and a strong prior on the image under scrutiny. Toward this goal, much effort has been deployed in formulating models for US imaging, which usually require a large amount of memory to store the matrix coefficients. We present two different techniques, which take advantage of fast and matrix-free formulations derived for the measurement model and its adjoint, and rely on sparsity of US images in well-chosen models...
March 2018: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Stephan Ellmann, Ferdinand Kammerer, Thomas Allmendinger, Matthias Hammon, Rolf Janka, Michael Lell, Michael Uder, Manuel Kramer
RATIONALE AND OBJECTIVES: This study aimed to determine the potential degree of radiation dose reduction achievable using Advanced Modeled Iterative Reconstruction (ADMIRE) in abdominal computed tomography (CT) while maintaining image quality. Moreover, this study compared differences in image noise reduction of this iterative algorithm with radiation dose reduction. METHODS: Eleven consecutive patients scheduled for abdominal CT were scanned according to our institute's standard protocol (100 kV, 289 reference mAs)...
February 27, 2018: Academic Radiology
Liang Lu, Lin Qi, Yisong Luo, Hengchao Jiao, Junyu Dong
Multi-spectral photometric stereo can recover pixel-wise surface normal from a single RGB image. The difficulty lies in that the intensity in each channel is the tangle of illumination, albedo and camera response; thus, an initial estimate of the normal is required in optimization-based solutions. In this paper, we propose to make a rough depth estimation using the deep convolutional neural network (CNN) instead of using depth sensors or binocular stereo devices. Since high-resolution ground-truth data is expensive to obtain, we designed a network and trained it with rendered images of synthetic 3D objects...
March 2, 2018: Sensors
Doris Leithner, Julian L Wichmann, Scherwin Mahmoudi, Simon S Martin, Moritz H Albrecht, Thomas J Vogl, Jan-Erik Scholtz
OBJECTIVES: To investigate the impact of low-tube-voltage 90-kVp acquisition combined with advanced modeled iterative reconstruction algorithm (Admire) on radiation exposure, image quality, artifacts, and assessment of stenosis in carotid and intracranial CT-angiography (CTA). METHODS: Dual-energy CTA studies of 43 patients performed on a third-generation 192-slice dual-source CT were retrospectively evaluated. Intraindividual comparison of 90-kVp and linearly-blended 120-kVp equivalent image series (M_0...
March 1, 2018: British Journal of Radiology
Kazuya Minamishima, Koichi Sugisawa, Yoshitake Yamada, Masahiro Jinzaki
The purpose of this phantom study was to investigate the feasibility of dose reduction with hybrid iterative reconstruction, with and without a noise power spectrum (NPS) model, using both quantitative and qualitative evaluations. Standard dose (SD), three-quarter dose (TQD), and half-dose (HD) of radiation were used. Images were reconstructed with filtered back projection (FBP), adaptive iterative dose reduction 3D (AIDR 3D) (MILD, STR), and AIDR 3D enhanced (eAIDR 3D) (eMILD, eSTR). An NPS analysis, task-based modulation transfer function (MTFtask ) analysis, and comparisons of low-contrast detectability and image texture were performed...
February 28, 2018: Journal of Applied Clinical Medical Physics
Yeong Shiong Chiew, Chee Pin Tan, J Geoffrey Chase, Yeong Woei Chiew, Thomas Desaive, Azrina Md Ralib, Mohd Basri Mat Nor
BACKGROUND AND OBJECTIVE: Respiratory mechanics estimation can be used to guide mechanical ventilation (MV) but is severely compromised when asynchronous breathing occurs. In addition, asynchrony during MV is often not monitored and little is known about the impact or magnitude of asynchronous breathing towards recovery. Thus, it is important to monitor and quantify asynchronous breathing over every breath in an automated fashion, enabling the ability to overcome the limitations of model-based respiratory mechanics estimation during asynchronous breathing ventilation...
April 2018: Computer Methods and Programs in Biomedicine
Taihei Inoue, Takeshi Nakaura, Morikatsu Yoshida, Koichi Yokoyama, Hiroyuki Uetani, Seitaro Oda, Daisuke Utsunomiya, Mika Kitajima, Kazunori Harada, Yasuyuki Yamashita
PURPOSE: The purpose of this study is to determine whether iterative model reconstruction (IMR) optimized for brain CT could improve the detection of acute stroke in the setting of thin image slices and narrow window settings. METHODS: We retrospectively reviewed 27 patients who presented acute middle cerebral artery (MCA) stroke. Images were reconstructed using filtered back projection (FBP; 1- and 5-mm slice thickness) and IMR (1 mm thickness), and contrast-to-noise ratios (CNRs) of infarcted and non-infarcted areas were compared...
February 23, 2018: Neuroradiology
Y Noda, S Goshima, S Nagata, T Miyoshi, H Kawada, N Kawai, Y Tanahashi, M Matsuo
AIM: To compare right adrenal vein (RAV) visualisation and contrast enhancement degree on adrenal venous phase images reconstructed using adaptive statistical iterative reconstruction (ASiR) and model-based iterative reconstruction (MBIR) techniques. MATERIAL AND METHODS: This prospective study was approved by the institutional review board, and written informed consent was waived. Fifty-seven consecutive patients who underwent adrenal venous phase imaging were enrolled...
February 16, 2018: Clinical Radiology
Rebekah H Griesenauer, Jared A Weis, Lori R Arlinghaus, Ingrid M Meszoely, Michael I Miga
Biomechanical breast models have been employed for applications in image registration and diagnostic analysis, breast augmentation simulation, and for surgical and biopsy guidance. Accurate applications of stress-strain relationships of tissue within the breast can improve the accuracy of biomechanical models that attempt to simulate breast deformations. Reported stiffness values for adipose, glandular, and cancerous tissue types vary greatly. Variations in reported stiffness properties have been attributed to differences in testing methodologies and assumptions, measurement errors, and natural interpatient differences in tissue elasticity...
January 2018: Journal of Medical Imaging
Shuki Maruyama, Yasuhiro Fukushima, Yuta Miyamae, Koji Koizumi
This study aimed to investigate the effects of parameter presets of the forward projected model-based iterative reconstruction solution (FIRST) on the accuracy of pulmonary nodule volume measurement. A torso phantom with simulated nodules [diameter: 5, 8, 10, and 12 mm; computed tomography (CT) density: - 630 HU] was scanned with a multi-detector CT at tube currents of 10 mA (ultra-low-dose: UL-dose) and 270 mA (standard-dose: Std-dose). Images were reconstructed with filtered back projection [FBP; standard (Std-FBP), ultra-low-dose (UL-FBP)], FIRST Lung (UL-Lung), and FIRST Body (UL-Body), and analyzed with a semi-automatic software...
February 10, 2018: Radiological Physics and Technology
Zheng Xu, Sheng Wang, Yeqing Li, Feiyun Zhu, Junzhou Huang
The most recent history of parallel Magnetic Resonance Imaging (pMRI) has in large part been devoted to finding ways to reduce acquisition time. While joint total variation (JTV) regularized model has been demonstrated as a powerful tool in increasing sampling speed for pMRI, however, the major bottleneck is the inefficiency of the optimization method. While all present state-of-the-art optimizations for the JTV model could only reach a sublinear convergence rate, in this paper, we squeeze the performance by proposing a linear-convergent optimization method for the JTV model...
February 8, 2018: Neuroinformatics
Hong Zhu, Xinming Tang, Junfeng Xie, Weidong Song, Fan Mo, Xiaoming Gao
There are many problems in existing reconstruction-based super-resolution algorithms, such as the lack of texture-feature representation and of high-frequency details. Multi-scale detail enhancement can produce more texture information and high-frequency information. Therefore, super-resolution reconstruction of remote-sensing images based on adaptive multi-scale detail enhancement (AMDE-SR) is proposed in this paper. First, the information entropy of each remote-sensing image is calculated, and the image with the maximum entropy value is regarded as the reference image...
February 7, 2018: Sensors
Markus Zimmermann, Zaheer Abbas, Krzysztof Dzieciol, N Jon Shah
A new reconstruction method, coined MIRAGE, is presented for accurate, fast, and robust parameter mapping of multiple-echo gradient-echo (MEGE) imaging, the basis sequence of novel quantitative magnetic resonance imaging techniques such as water content and susceptibility mapping. Assuming that the temporal signal can be modeled as a sum of damped complex exponentials, MIRAGE performs model-based reconstruction of undersampled data by minimizing the rank of local Hankel matrices. It further incorporates multi-channel information and spatial prior knowledge...
February 2018: IEEE Transactions on Medical Imaging
Tao Feng, Jizhe Wang, Benjamin M W Tsui
PURPOSE: The goal of this study is to develop and evaluate four post-reconstruction respiratory and cardiac (R&C) motion vector field (MVF) estimation methods for cardiac 4D PET data. METHOD: In Method 1, the dual R&C motions were estimated directly from the dual R&C gated images. In Methods 2, respiratory motion (RM) and cardiac motion (CM) were separately estimated from the respiratory gated only and cardiac gated only images. The effects of RM on CM estimation were modeled in Method 3 by applying an image-based RM correction on the cardiac gated images before CM estimation, the effects of CM on RM estimation were neglected...
February 5, 2018: Medical Physics
Shoji Tominaga, Keita Hirai, Takahiko Horiuchi
The present paper proposes a method to estimate the bispectral Donaldson matrices of fluorescent objects in a scene with a spectral imaging system. Multiple ordinary light sources with continuous spectral-power distributions are projected sequentially onto object surfaces without controlling the spectral shape of the illumination source. The estimation problem of the Donaldson matrices is solved as an optimization problem, where the residual error of observations by the spectral imaging system is minimized...
January 22, 2018: Optics Express
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