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Dual energy CT

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https://www.readbyqxmd.com/read/28430715/computed-tomography-of-the-head-and-neck-region-for-tumor-staging-comparison-of-dual-source-dual-energy-and-low-kilovolt-single-energy-acquisitions
#1
Matthias Stefan May, Joscha Bruegel, Michael Brand, Marco Wiesmueller, Bernhard Krauss, Thomas Allmendinger, Michael Uder, Wolfgang Wuest
PURPOSE: The aim of this study was to intra-individually compare the image quality obtained by dual-source, dual-energy (DSDE) computed tomography (CT) examinations and different virtual monoenergetic reconstructions to a low single-energy (SE) scan. MATERIALS AND METHODS: Third-generation DSDE-CT was performed in 49 patients with histologically proven malignant disease of the head and neck region. Weighted average images (WAIs) and virtual monoenergetic images (VMIs) for low (40 and 60 keV) and high (120 and 190 keV) energies were reconstructed...
April 20, 2017: Investigative Radiology
https://www.readbyqxmd.com/read/28422806/improvement-of-image-quality-in-unenhanced-dual-layer-ct-of-the-head-using-virtual-monoenergetic-images-compared-with-polyenergetic-single-energy-ct
#2
Victor Neuhaus, Nuran Abdullayev, Nils Große Hokamp, Gregor Pahn, Christoph Kabbasch, Anastasios Mpotsaris, David Maintz, Jan Borggrefe
OBJECTIVES: The aims of this study were to compare virtual monoenergetic images and polyenergetic images reconstructed from unenhanced dual-layer detector computed tomography (DLCT) of the head and to determine kiloelectron volt levels that optimize image quality, particularly the gray-white matter contrast, and reduce beam hardening artifacts caused by the skull. MATERIALS AND METHODS: Institutional review board approval was obtained. Forty patients that received DLCT were included in this retrospective study; of these patients, 22 were women and 18 were men...
April 19, 2017: Investigative Radiology
https://www.readbyqxmd.com/read/28418823/dual-energy-ct-in-cardiovascular-imaging-edited-by-patricia-m-carrascosa-ricardo-c-cury-mario-garcia-and-jonathon-a-leipsic-new-york-ny-springer-science-business-media-2015-isbn-978-3-319-21226-5-hardcover-109-00-pp-277
#3
https://www.readbyqxmd.com/read/28410679/dual-energy-imaging-method-to-improve-the-image-quality-and-the-accuracy-of-dose-calculation-for-cone-beam-computed-tomography
#4
Kuo Men, Jianrong Dai, Xinyuan Chen, Minghui Li, Ke Zhang, Peng Huang
PURPOSE: To improve the image quality and accuracy of dose calculation for cone-beam computed tomography (CT) images through implementation of a dual-energy cone-beam computed tomography method (DE-CBCT), and evaluate the improvement quantitatively. METHODS: Two sets of CBCT projections were acquired using the X-ray volumetric imaging (XVI) system on a Synergy (Elekta, Stockholm, Sweden) system with 120kV (high) and 70kV (low) X-rays, respectively. Then, the electron density relative to water (relative electron density (RED)) of each voxel was calculated using a projection-based dual-energy decomposition method...
April 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28402129/consistency-of-renal-stone-volume-measurements-across-ct-scanner-model-and-reconstruction-algorithm-configurations
#5
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/28401803/imaging-advances-for-urolithiasis
#6
Joanne Andrea Dale, Rajan T Gupta, Daniele Marin, Michael Eric Lipkin, Glenn M Preminger
The prevalence of urinary stones in the United States has been described as 1 in 11 persons reporting a history of stones. Imaging plays a crucial role in diagnosis, management and follow-up for these patients and imaging technology over the last 100 years has advanced as the disease prevalence has increased. Computed tomography (CT) remains the gold standard for imaging urolithiasis and changes in this technology, with the addition of multidetector CT and dual-energy CT, as well as the changes in utilization of CT, have decreased the radiation dose encountered by patients and allowed for improved stone detection...
April 12, 2017: Journal of Endourology
https://www.readbyqxmd.com/read/28401118/frequency-of-and-variation-in-low-value-care-in-primary-care-a-retrospective-cohort-study
#7
Ciara Pendrith, Meghan Bhatia, Noah M Ivers, Graham Mecredy, Karen Tu, Gillian A Hawker, Susan B Jaglal, Lynn Wilson, Kimberly Wintemute, Richard H Glazier, Wendy Levinson, R Sacha Bhatia
BACKGROUND: Low-value care, defined as care with a lack of benefit, can lead to higher health care costs, inconvenience to patients and, in some cases, harm to patients. The objectives of this study are to conduct exploratory analyses to understand how frequently selected low-value tests are ordered, to assess the degree of variation in ordering that exists across regions and practices, and to identify services that may warrant further investigation and targeted interventions. METHODS: We conducted a population-based retrospective cohort study using administrative health care databases from Ontario to identify rates of use of the following low-value services between fiscal years 2008/09 and 2012/13: computed tomography (CT) or magnetic resonance imaging (MRI) after a diagnosis of low back pain, Papanicolaou testing in women less than 21 years of age or older than 69 years of age and repeated dual-energy X-ray absorptiometry (DEXA) scanning within 2 years of an index scan...
January 2017: CMAJ Open
https://www.readbyqxmd.com/read/28397977/methodological-accuracy-of-image-based-electron-density-assessment-using-dual-energy-computed-tomography
#8
Christian Möhler, Patrick Wohlfahrt, Christian Richter, Steffen Greilich
PURPOSE: Electron density is the most important tissue property influencing photon and ion dose distributions in radiotherapy patients. Dual-energy computed tomography (DECT) enables the determination of electron density by combining the information on photon attenuation obtained at two different effective x-ray energy spectra. Most algorithms suggested so far use the CT numbers provided after image reconstruction as input parameters, i.e. are imaged-based. To explore the accuracy that can be achieved with these approaches, we quantify the intrinsic methodological and calibration uncertainty of the seemingly simplest approach...
April 11, 2017: Medical Physics
https://www.readbyqxmd.com/read/28394083/bone-volume-to-total-volume-ratio-measured-in-trabecular-bone-by-single-sided-nmr-devices
#9
Leonardo Brizi, Marco Barbieri, Fabio Baruffaldi, Villiam Bortolotti, Chiara Fersini, Huabing Liu, Marcel Nogueira d'Eurydice, Sergei Obruchkov, Fangrong Zong, Petrik Galvosas, Paola Fantazzini
PURPOSE: Reduced bone strength is associated with a loss of bone mass, usually evaluated by dual-energy X-ray absorptiometry, although it is known that the bone microstructure also affects the bone strength. Here, a method is proposed to measure (in laboratory) the bone volume-to-total volume ratio by single-sided NMR scanners, which is related to the microstructure of the trabecular bone. METHODS: Three single-sided scanners were used on animal bone samples. These low-field, mobile, low-cost devices are able to detect the NMR signal, regardless of the sample sizes, without the use of ionizing radiations, with the further advantage of signal localization offered by their intrinsic magnetic field gradients...
April 10, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28392937/reduced-lpl-and-subcutaneous-lipid-storage-capacity-are-associated-with-metabolic-syndrome-in-postmenopausal-women-with-obesity
#10
M C Serra, A S Ryan, A P Goldberg
OBJECTIVES: This study examines the hypothesis that lower adipose tissue lipoprotein lipase (LPL) activity and a limited capacity for subcutaneous adipocyte expansion will be associated with metabolic syndrome (MSyn) in postmenopausal women who are overweight and obese. METHODS: Women (N = 150; age 60 ± 1 year; BMI: 31.5 ± 0.3 kg m(-2); mean ± standard errors of the means [SEM]) with and without MSyn had dual-energy X-ray absorptiometry scans for total body fat, CT scans for visceral and subcutaneous abdominal adipose tissue areas, lipid and glucose metabolic profiles, and abdominal and gluteal fat aspirations for subcutaneous fat cell weight (FCW; N = 150) and LPL activity (N = 100)...
March 2017: Obesity Science & Practice
https://www.readbyqxmd.com/read/28387962/comparative-investigation-of-bone-mineral-density-using-ct-and-dexa-in-a-canine-femoral-model
#11
Karin Lucas, Bernd-Arno Behrens, Ingo Nolte, Vladimir Galindo-Zamora, Stefanie Betancur, Amer Almohallami, Anas Bouguecha, Ayman Mostafa, Matthias Lerch, Christina Stukenborg-Colsman, Patrick Wefstaedt
Bone density measurements using computed tomography (CT) instead of dual-energy X-ray absorptiometry (DEXA) are currently of great interest in human and veterinary medical research as it would be beneficial to use CT scans obtained for other indications also for determining bone density. For Hounsfield units (HU) measured with CT in specific regions of interests (ROIs) in one or several slice/s a corrrelation with bone mineral density (BMD) measured by DEXA in humans and dogs of between 0.44 and 0.77 is reported in the literature...
April 7, 2017: Journal of Orthopaedic Research: Official Publication of the Orthopaedic Research Society
https://www.readbyqxmd.com/read/28381034/dual-energy-micro-ct-with-a-dual-layer-dual-color-single-crystal-scintillator
#12
Daniel Simon Maier, Jonathan Schock, Franz Pfeiffer
A wide range of X-ray imaging applications demand micrometer spatial resolution. In material science and biology especially, there is a great interest in material determination and material separation methods. Here we present a new detector design that allows the recording of a low- and a high-energy radiography image simultaneously with micrometer spatial resolution. The detector system is composed of a layered scintillator stack, two CCDs and an optical system to image the scintillator responses onto the CCDs...
March 20, 2017: Optics Express
https://www.readbyqxmd.com/read/28374079/accuracy-of-bone-mineral-density-quantification-using-dual-layer-spectral-detector-ct-a-phantom-study
#13
Robbert W van Hamersvelt, Arnold M R Schilham, Klaus Engelke, Annemarie M den Harder, Bart de Keizer, Harald J Verhaar, Tim Leiner, Pim A de Jong, Martin J Willemink
OBJECTIVES: To investigate the accuracy of bone mineral density (BMD) quantification using dual-layer spectral detector CT (SDCT) at various scan protocols. METHODS: Two validated anthropomorphic phantoms containing inserts of 50-200 mg/cm(3) calcium hydroxyapatite (HA) were scanned using a 64-slice SDCT scanner at various acquisition protocols (120 and 140 kVp, and 50, 100 and 200 mAs). Regions of interest (ROIs) were placed in each insert and mean attenuation profiles at monochromatic energy levels (90-200 keV) were constructed...
April 3, 2017: European Radiology
https://www.readbyqxmd.com/read/28372786/clinical-application-of-effective-atomic-number-for-classifying-non-calcified-coronary-plaques-by-dual-energy-computed-tomography
#14
Shun Nakajima, Hiroyuki Ito, Tetsuya Mitsuhashi, Yutaka Kubo, Kazuhiro Matsui, Isao Tanaka, Rika Fukui, Hisako Omori, Takashi Nakaoka, Hiroshi Sakura, Eiko Ueno, Haruhiko Machida
BACKGROUND AND AIMS: Coronary computed tomography (CT) angiography allows non-invasive classification of non-calcified coronary plaques (NCCPs) based on Hounsfield unit (HU) values. This methodology, however, is somewhat limited for reliable classification of NCCPs. Therefore, we evaluated the effective atomic number (EAN) for classifying NCCPs by single-source dual-energy CT with fast tube voltage switching (SSDECT). METHODS: We prospectively enrolled 18 patients undergoing both SSDECT and intravascular ultrasonography (IVUS)...
March 21, 2017: Atherosclerosis
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
#15
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/28365785/selection-of-optimal-tube-potential-settings-for-dual-energy-ct-virtual-mono-energetic-imaging-of-iodine-in-the-abdomen
#16
Gregory Michalak, Joshua Grimes, Joel Fletcher, Ahmed Halaweish, Lifeng Yu, Shuai Leng, Cynthia McCollough
PURPOSE: To determine the appropriate tube potential settings for dual-source, dual-energy data acquisition across a range of phantom sizes, and to determine the optimal photon energies for virtual mono-energetic imaging. METHODS: Water phantoms (15-50-cm wide) containing an iodine test object were scanned on a third-generation dual-source CT scanner using all available tube potential pairs. Virtual mono-energetic images at 40, 50, 60, and 70 keV were produced using Mono-energetic Plus...
April 1, 2017: Abdominal Radiology
https://www.readbyqxmd.com/read/28353408/characterization-of-small-focal-renal-lesions-diagnostic-accuracy-with-single-phase-contrast-enhanced-dual-energy-ct-with-material-attenuation-analysis-compared-with-conventional-attenuation-measurements
#17
Daniele Marin, Drew Davis, Kingshuk Roy Choudhury, Bhavik Patel, Rajan T Gupta, Achille Mileto, Rendon C Nelson
Purpose To determine whether single-phase contrast material-enhanced dual-energy material attenuation analysis improves the characterization of small (1-4 cm) renal lesions compared with conventional attenuation measurements by using histopathologic analysis and follow-up imaging as the clinical reference standards. Materials and Methods In this retrospective, HIPAA-compliant, institutional review board-approved study, 136 consecutive patients (95 men and 41 women; mean age, 54 years) with 144 renal lesions (111 benign, 33 malignant) measuring 1-4 cm underwent single-energy unenhanced and contrast-enhanced dual-energy computed tomography (CT) of the abdomen...
March 28, 2017: Radiology
https://www.readbyqxmd.com/read/28352977/single-energy-pediatric-chest-computed-tomography-with-spectral-filtration-at-100-kvp-effects-on-radiation-parameters-and-image-quality
#18
Boris Bodelle, Constanze Fischbach, Christian Booz, Ibrahim Yel, Claudia Frellesen, Moritz Kaup, Martin Beeres, Thomas J Vogl, Jan-Erik Scholtz
BACKGROUND: Most of the applied radiation dose at CT is in the lower photon energy range, which is of limited diagnostic importance. OBJECTIVE: To investigate image quality and effects on radiation parameters of 100-kVp spectral filtration single-energy chest CT using a tin-filter at third-generation dual-source CT in comparison to standard 100-kVp chest CT. MATERIALS AND METHODS: Thirty-three children referred for a non-contrast chest CT performed on a third-generation dual-source CT scanner were examined at 100 kVp with a dedicated tin filter with a tube current-time product resulting in standard protocol dose...
March 28, 2017: Pediatric Radiology
https://www.readbyqxmd.com/read/28352965/dual-energy-ct-to-diagnose-pseudoedema-in-contrast-induced-encephalopathy-following-cerebral-angiography
#19
Gabriel L Pagani-Estévez, Deena M Nasr, Waleed Brinjikji, Avital Perry, Jennifer E Fugate
BACKGROUND: Contrast-induced encephalopathy (CIE) is a syndrome that may be clinically unrecognized and misdiagnosed as cerebral edema. METHODS: Case report and review. RESULTS: A 72-year-old woman was admitted for elective endovascular embolization of a 10-mm left anterior communicating artery aneurysm. One hour post-procedure, she acutely developed global aphasia. Emergent head computed tomography (CT) and computed tomography-angiography (CTA) showed high attenuation of the left hemispheric subarachnoid spaces interpreted as hemispheric edema; emergent magnetic resonance imaging revealed left hemispheric punctate infarcts...
March 28, 2017: Neurocritical Care
https://www.readbyqxmd.com/read/28350547/assessment-of-vectorial-total-variation-penalties-on-realistic-dual-energy-ct-data
#20
David S Rigie, Adrian A Sanchez, Patrick J La Rivière
Vectorial extensions of total variation have recently been developed for regularizing the reconstruction and denoising of multi-channel images, such as those arising in spectral computed tomography. Early studies have focused mainly on simulated, piecewise-constant images whose structure may favor total-variation penalties. In the current manuscript, we apply vectorial total variation to real dual-energy CT data of a whole turkey in order to determine if the same benefits can be observed in more complex images with anatomically realistic textures...
April 21, 2017: Physics in Medicine and Biology
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