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iterative reconstruction

William D Erwin, Aaron C Jessop, Martha V Mar, Homer A Macapinlac, Osama R Mawlawi
OBJECTIVE: The aim of this study was to assess the feasibility of IQ-SPECT gated blood pool (MUGA) under conditions of decreased scan time (ST). PATIENTS AND METHODS: Ten patients underwent routine 26-min, two-view planar, followed by LEHR and IQ-SPECT MUGA, on a Siemens dual-head Symbia scanner. Six 'back and forth' 4-min SPECT scans were summed into 4-, 8-, 12-, 16-, 20-, and 24-min equivalent scans, and reconstructed iteratively (IQ-SPECT and LEHR) and with FBP (LEHR)...
October 21, 2016: Nuclear Medicine Communications
Bertram J Wilm, Christoph Barmet, Simon Gross, Lars Kasper, S Johanna Vannesjo, Max Haeberlin, Benjamin E Dietrich, David O Brunner, Thomas Schmid, Klaas P Pruessmann
PURPOSE: The purpose of this work was to improve the quality of single-shot spiral MRI and demonstrate its application for diffusion-weighted imaging. METHODS: Image formation is based on an expanded encoding model that accounts for dynamic magnetic fields up to third order in space, nonuniform static B0 , and coil sensitivity encoding. The encoding model is determined by B0 mapping, sensitivity mapping, and concurrent field monitoring. Reconstruction is performed by iterative inversion of the expanded signal equations...
October 21, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
T J Tan, Kenneth K Lau, Dana Jackson, Nicholas Ardley, Adina Borasu
The purpose of this study was to assess the efficacy of model-based iterative reconstruction (MBIR), statistical iterative reconstruction (SIR), and filtered back projection (FBP) image reconstruction algorithms in the delineation of ureters and overall image quality on non-enhanced computed tomography of the renal tracts (NECT-KUB). This was a prospective study of 40 adult patients who underwent NECT-KUB for investigation of ureteric colic. Images were reconstructed using FBP, SIR, and MBIR techniques and individually and randomly assessed by two blinded radiologists...
October 21, 2016: Emergency Radiology
Helle Precht, Pieter H Kitslaar, Alexander Broersen, Jouke Dijkstra, Oke Gerke, Jesper Thygesen, Kenneth Egstrup, Jess Lambrechtsen
PURPOSE: The purpose of this study was to study the effect of iterative reconstruction (IR) software on quantitative plaque measurements in coronary computed tomography angiography (CCTA). METHODS: Thirty patients with a three clinical risk factors for coronary artery disease (CAD) had one CCTA performed. Images were reconstructed using FBP, 30% and 60% adaptive statistical IR (ASIR). Coronary plaque analysis was performed as per patient and per vessel (LM, LAD, CX and RCA) measurements...
September 28, 2016: Journal of Cardiovascular Computed Tomography
Kevin Kalisz, Ji Buethe, Sachin S Saboo, Suhny Abbara, Sandra Halliburton, Prabhakar Rajiah
Computed tomography is vulnerable to a wide variety of artifacts, including patient- and technique-specific artifacts, some of which are unique to imaging of the heart. Motion is the most common source of artifacts and can be caused by patient, cardiac, or respiratory motion. Cardiac motion artifacts can be reduced by decreasing the heart rate and variability and the duration of data acquisition; adjusting the placement of the data window within a cardiac cycle; performing single-heartbeat scanning; and using multisegment reconstruction, motion-correction algorithms, and electrocardiographic editing...
October 21, 2016: Radiographics: a Review Publication of the Radiological Society of North America, Inc
Zhe Zhang, Bing Zhang, Ming Li, Xue Liang, Xiaodong Chen, Renyuan Liu, Xin Zhang, Hua Guo
PURPOSE: To report a diffusion imaging technique insensitive to off-resonance artifacts and motion-induced ghost artifacts using mulitshot Cartesian turbo spin-echo (TSE) acquisition and iterative POCS-based reconstruction of multiplexed sensitivity encoded magnetic resonance imaging (MRI) (POCSMUSE) for phase correction. MATERIALS AND METHODS: Phase insensitive diffusion preparation was used to deal with the violation of the Carr-Purcell-Meiboom-Gill (CPMG) conditions of TSE diffusion-weighted imaging (DWI), followed by a mulitshot Cartesian TSE readout for data acquisition...
October 20, 2016: Journal of Magnetic Resonance Imaging: JMRI
Nobuhiro Yada, Hideo Onishi, Masahiro Miyai, Kentarou Ozasa, Masuo Haramoto, Yasushi Yamamoto, Shuhei Yamaguchi, Hajime Kitagaki
PURPOSE: This study aimed to verify the resolution recovery for each collimator in the brain perfusion image. METHOD: To verify the effect of the resolution recovery for each collimator, we evaluated via the three-dimensional brain phantom (phantom) and the normal brain perfusion single photon emission computed tomography (SPECT) data. These data were reconstructed using the three-dimensional ordered subset expectation maximization method (3D-OSEM) (Evolution for bone(TM)) that was performed with scatter correction, attenuation correction, and resolution recovery (RR)...
2016: Nihon Hoshasen Gijutsu Gakkai Zasshi
Jorge Mejia, Ana Claudia Camargo Miranda, Ana Claudia Ranucci Durante, Larissa Rolim de Oliveira, Marycel Rosa Felisa Figols de Barboza, Katerin Taboada Rosell, Daniele Pereira Jardim, Alexandre Holthausen Campos, Marilia Alves Dos Reis, Marcela Forli Catanoso, Orfa Yineth Galvis-Alonso, Francisco Romero Cabral
Objective: To present the result of upgrading a clinical gamma-camera to be used to obtain in vivo tomographic images of small animal organs, and its application to register cardiac, renal and neurological images. Methods: An updated version of the miniSPECT upgrading device was built, which is composed of mechanical, electronic and software subsystems. The device was attached to a Discovery VH (General Electric Healthcare) gamma-camera, which was retired from the clinical service and installed at the Centro de Imagem Pré-Clínica of the Hospital Israelita Albert Einstein...
July 2016: Einstein
Xiaoqing Wang, Arun A Joseph, Oleksandr Kalentev, K Dietmar Merboldt, Dirk Voit, Volkert B Roeloffs, Maaike van Zalk, Jens Frahm
OBJECTIVE: To develop a novel method for rapid myocardial T1 mapping at high spatial resolution. METHODS: The proposed strategy represents a single-shot inversion-recovery (IR) experiment triggered to early diastole during a brief breathhold. The measurement combines an adiabatic inversion pulse with a real-time readout by highly undersampled radial FLASH, iterative image reconstruction and T1 fitting with automatic deletion of systolic frames. The method was implemented on a 3 T MRI system using a GPU-equipped bypass computer for online application...
October 19, 2016: British Journal of Radiology
Sangyun Lee, Heejin Kwon, Jihan Cho
RATIONALE AND OBJECTIVES: To investigate image quality characteristics of abdominal computed tomography (CT) scans reconstructed with adaptive statistical iterative reconstruction V (ASIR-V) vs currently using applied adaptive statistical iterative reconstruction (ASIR). MATERIALS AND METHOD: This institutional review board-approved study included 35 consecutive patients who underwent CT of the abdomen. Among these 35 patients, 27 with focal liver lesions underwent abdomen CT with a 128-slice multidetector unit using the following parameters: fixed noise index of 30, 1...
October 10, 2016: Academic Radiology
Michael Messerli, Fabian Rengier, Lotus Desbiolles, Niklas F Ehl, Ralf W Bauer, Sebastian Leschka, Hatem Alkadhi, Simon Wildermuth, Claas P Nähle
RATIONALE AND OBJECTIVES: To evaluate the influence of advanced modeled iterative reconstruction (ADMIRE) on the coronary artery calcium (CAC) scores by computed tomography (CT). MATERIALS AND METHODS: Sixty patients underwent CAC imaging with dual-source 192-slice CT. Agatston, volume and mass score were calculated from filtered back projection (FBP) and iterative reconstructions with different levels of ADMIRE. Friedman test and Wilcoxon rank sum test were used for multiple comparisons of CAC values and the difference ratio among different ADMIRE groups using FBP as reference...
October 11, 2016: Academic Radiology
Hyungjin Kim, Chang Min Park, Myunghee Lee, Sang Joon Park, Yong Sub Song, Jong Hyuk Lee, Eui Jin Hwang, Jin Mo Goo
PURPOSE: To identify the impact of reconstruction algorithms on CT radiomic features of pulmonary tumors and to reveal and compare the intra- and inter-reader and inter-reconstruction algorithm variability of each feature. METHODS: Forty-two patients (M:F = 19:23; mean age, 60.43±10.56 years) with 42 pulmonary tumors (22.56±8.51mm) underwent contrast-enhanced CT scans, which were reconstructed with filtered back projection and commercial iterative reconstruction algorithm (level 3 and 5)...
2016: PloS One
Kevin P Murphy, Patrick D McLaughlin, Maria Twomey, Vincent E Chan, Fiachra Moloney, Adrian J Fung, Faimee E Chan, Tafline Kao, Siobhan B O'Neill, Benjamin Watson, Owen J O'Connor, Michael M Maher
INTRODUCTION: We assess the ability of low-dose hybrid iterative reconstruction (IR) and 'pure' model-based IR (MBIR) images to maintain accurate Hounsfield unit (HU)-determined tissue characterization. METHODS: Standard-protocol (SP) and low-dose modified-protocol (MP) CTs were contemporaneously acquired in 34 Crohn's disease patients referred for CT. SP image reconstruction was via the manufacturer's recommendations (60% FBP, filtered back projection; 40% ASiR, Adaptive Statistical iterative Reconstruction; SP-ASiR40)...
October 13, 2016: Journal of Medical Imaging and Radiation Oncology
David L Thiele, Sarah-Ellyana Aliuddin, Mike Irvine, George P McGill
A computed tomography radiation dose survey was performed within our enterprise using three age-based paediatric phantoms representing a 1, 5 and 10 years old. Twenty-seven scanners were surveyed with volume computed tomography dose index and dose length product data collected for head, chest and abdomen-pelvis protocols at each age. Reconstruction method e.g. filtered back projection (FBP) or iterative (IR) was also recorded. About two-thirds of the 1 year old FBP chest scans exceeded the national Baby diagnostic reference level (DRL)...
October 11, 2016: Australasian Physical & Engineering Sciences in Medicine
Ming Li, Cheng Zhang, Chengtao Peng, Yihui Guan, Pin Xu, Mingshan Sun, Jian Zheng
Low-dose computed tomography (CT) reconstruction is a challenging problem in medical imaging. To complement the standard filtered back-projection (FBP) reconstruction, sparse regularization reconstruction gains more and more research attention, as it promises to reduce radiation dose, suppress artifacts, and improve noise properties. In this work, we present an iterative reconstruction approach using improved smoothed l0 (SL0) norm regularization which is used to approximate l0 norm by a family of continuous functions to fully exploit the sparseness of the image gradient...
2016: BioMed Research International
Zhiguo Zhou, Haixi Chen, Wei Wei, Shanghui Zhou, Jingbo Xu, Xifu Wang, Qingguo Wang, Guixiang Zhang, Zhuoli Zhang, Linfeng Zheng
PURPOSE: The purpose of this study was to evaluate the image quality and radiation dose in computed tomography urography (CTU) images acquired with a low kilovoltage peak (kVp) in combination with an adaptive statistical iterative reconstruction (ASiR) algorithm. METHODS: A total of 45 subjects (18 women, 27 men) who underwent CTU with kV assist software for automatic selection of the optimal kVp were included and divided into two groups (A and B) based on the kVp and image reconstruction algorithm: group A consisted of patients who underwent CTU with a 80 or 100 kVp and whose images were reconstructed with the 50% ASiR algorithm (n=32); group B consisted of patients who underwent CTU with a 120 kVp and whose images were reconstructed with the filtered back projection (FBP) algorithm (n=13)...
2016: American Journal of Translational Research
Kamil J Chodzyński, Simone Gremmo, Omer F Eker, Jacques Lalmand, Adel Aminian, Daniel Ribeiro de Sousa, Karim Zouaoui Boudjeltia, Grégory Coussement
BACKGROUND: Since hemodynamics plays a key role in the development and evolution of cardiovascular pathologies, physician's decision must be based on proper monitoring of relevant physiological flow quantities. METHODS: A numerical analysis of the error introduced by an intravascular Doppler guide wire on the peak velocity measurements has been carried out. The effect of probe misalignment (±10°) with respect to the vessel axis was investigated. Numerical simulations were performed on a realistic 3D geometry, reconstructed from coronary angiography images...
October 10, 2016: Biomedical Engineering Online
Kevin P Murphy, Liam J Healy, Lee Crush, Maria Twomey, Fiachra Moloney, Sylvia Sexton, Owen J O'Connor, Michael M Maher
AIM: To assess the effect of neutral (NC) and positive (PC) oral contrast use on patient dose in low-dose abdominal computed tomography (CT). METHODS: Low-dose clinically indicated CTs were performed on 79 Crohn's patients (35 = PC, 1 L 2% gastrografin; 44 = NC, 1.5 L polyethylene glycol). Scanner settings for both acquisitions were identical apart from 25 s difference in intravenous contrast timing. Body mass index (BMI), scan-ranges, dose-length product and size-specific dose estimated were recorded...
September 28, 2016: World Journal of Radiology
Christian Schou Oxvig, Thomas Arildsen, Torben Larsen
The use of compressed sensing in atomic force microscopy (AFM) can potentially speed-up image acquisition, lower probe-specimen interaction, or enable super resolution imaging. The idea in compressed sensing for AFM is to spatially undersample the specimen, i.e. only acquire a small fraction of the full image of it, and then use advanced computational techniques to reconstruct the remaining part of the image whenever this is possible. Our initial experiments have shown that it is possible to leverage inherent structure in acquired AFM images to improve image reconstruction...
September 21, 2016: Ultramicroscopy
G Mirouse, R Rousseau, L Casabianca, M A Ettori, B Granger, H Pascal-Moussellard, F Khiami
INTRODUCTION: The surgical revision rate following anterior cruciate ligament (ACL) surgery is 3% at 2 years and 4% at 5 years. Revision ACL surgery raises the question of the type of graft to be used. The present study assessed return to sports and functional results after revision ACL reconstruction by fascia lata graft. The hypothesis was that fascia lata provides a reliable graft in revision ACL surgery. MATERIAL AND METHODS: A single-center retrospective continuous study included 30 sports players with a mean age of 26...
October 6, 2016: Orthopaedics & Traumatology, Surgery & Research: OTSR
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