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Spectral CT

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https://www.readbyqxmd.com/read/28436858/a-spectral-ct-method-to-directly-estimate-basis-material-maps-from-experimental-photon-counting-data
#1
Taly Schmidt, Rina Barber, Emil Sidky
The proposed spectral CT method solves the constrained one-step spectral CT reconstruction (cOSSCIR) optimization problem to estimate basis material maps while modeling the nonlinear X-ray detection process and enforcing convex constraints on the basis map images. In order to apply the optimization-based reconstruction approach to experimental data, the presented method empirically estimates the effective energy-window spectra using a calibration procedure. The amplitudes of the estimated spectra were further optimized as part of the reconstruction process to reduce ring artifacts...
April 24, 2017: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28431312/melatonin-charge-transfer-complex-with-2-3-dichloro-5-6-dicyano-1-4-benzoquinone-molecular-structure-dft-studies-thermal-analyses-evaluation-of-biological-activity-and-utility-for-determination-of-melatonin-in-pure-and-dosage-forms
#2
Gehad G Mohamed, Maher M Hamed, Nadia G Zaki, Mohamed M Abdou, Marwa El-Badry Mohamed, Abanoub Mosaad Abdallah
A simple, accurate and fast spectrophotometric method for the quantitative determination of melatonin (ML) drug in its pure and pharmaceutical forms was developed based on the formation of its charge transfer complex with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as an electron acceptor. The different conditions for this method were optimized accurately. The Lambert-Beer's law was found to be valid over the concentration range of 4-100μgmL(-1) ML. The solid form of the CT complex was structurally characterized by means of different spectral methods...
April 4, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
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
#3
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/28422502/arrays-of-ag-and-au-nanoparticles-with-terpyridine-and-thiophene-based-ligands-morphology-and-optical-responses
#4
Markéta Prusková, Veronika Sutrová, Miroslav Šlouf, Blanka Vlčková, Jiří Vohlídal, Ivana Šloufová
The assembly of Ag and Au nanoparticles (NPs) into nanoparticulate arrays mediated by terpyridine (tpy), 4'-(2-thienyl)terpyridine (T-tpy), and short α,ω-bis(tpy)oligothiophene ligands has been accomplished at the interface between the Ag or Au NP hydrosol and a solution of the molecular species in dichloromethane. The relationship between the morphology and the optical responses of the arrays has been investigated by advanced methods of TEM (transmission electron microscopy) image analysis and surface plasmon extinction (SPE) spectra...
April 19, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28421243/assessment-of-70-kev-virtual-monoenergetic-spectral-images-in-abdominal-ct-imaging-a-comparison-study-to-conventional-polychromatic-120-kvp-images
#5
Negin Rassouli, Hamid Chalian, Prabhakar Rajiah, Amar Dhanantwari, Luis Landeras
PURPOSE: To evaluate the image quality of 70-keV virtual monoenergetic (monoE) abdominal CT images compared to 120-kVp polychromatic images generated from a spectral detector CT (SDCT) scanner. METHODS: This prospective study included generation of a 120-kVp polychromatic dataset and a 70-keV virtual monoE dataset after a single contrast-enhanced CT acquisition on a SDCT scanner (Philips Healthcare) during portal venous phase. The attenuation values (HU), noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were measured in the liver, spleen, pancreas, kidney, aorta, portal vein, and muscle...
April 18, 2017: Abdominal Radiology
https://www.readbyqxmd.com/read/28416309/detection-of-apical-root-cracks-using-spectral-domain-and-swept-source-optical-coherence-tomography
#6
Bruna Paloma de Oliveira, Andréa Cruz Câmara, Daniel Amancio Duarte, Anderson Stevens Leonidas Gomes, Richard John Heck, Antonio Celso Dantas Antonino, Carlos Menezes Aguiar
INTRODUCTION: This study aimed to evaluate the ability of 2 optical coherence tomographic (OCT) systems to detect apical dentinal microcracks. METHODS: Twenty extracted human single-rooted mandibular incisors were selected. After root canal preparation with an R40 Reciproc file (VDW, Munich, Germany), the specimens presenting apical microcracks were identified using micro-computed tomographic (micro-CT) scanning as the gold standard. Then, the apical portions of the roots were imaged with spectral domain OCT (SD-OCT) and swept-source OCT systems, and the resulting images were blindly evaluated by 3 independent examiners to detect microcracks...
April 14, 2017: Journal of Endodontics
https://www.readbyqxmd.com/read/28403185/correlation-of-choroidal-thickness-and-ametropiain-young-adolescence
#7
Xiaolei Shao, Chang Zou, Bo Qin
Choroid has been proposed to participate in the regulation of light refraction by changing its thickness. The present study aims to analyze the characteristics of choroidal thickness (CT), and its correlation with refractive error, axial length and age in young ametropia. A total of 51 subjects (102 eyes), aged from 5 to 18 years old (mean age 10.04 ±2.78 years), with ametropia were included in the study. Choroidal imaging was obtained by enhanced depth imaging (EDI) of spectral domain Optical Coherence Tomography (OCT)...
2017: PloS One
https://www.readbyqxmd.com/read/28401372/choroidal-thickness-alterations-in-diabetic-nephropathy-patients-with-early-or-no-diabetic-retinopathy
#8
Can Kocasarac, Yavuz Yigit, Erkan Sengul, Yildirim Beyazit Sakalar
PURPOSE: To assess changes in choroidal thickness (CT) in diabetes patients with and without diabetic nephropathy using enhanced depth imaging spectral domain optical coherence tomography (EDI-OCT). METHODS: Thirty-five type 2 diabetes patients with a diagnosis of diabetic nephropathy (DNP) in nephrology department and 35 type 2 diabetes patients without nephropathy (non-DNP) were included in our prospective study consecutively. The control group comprised 34 healthy individuals...
April 11, 2017: International Ophthalmology
https://www.readbyqxmd.com/read/28398906/evaluation-of-the-i-breastsimulator-i-software-platform-for-breast-tomography
#9
Giovanni Mettivier, Kristina Bliznakova, Ioannis Sechopoulos, John Boone, Francesca Di Lillo, Antonio Sarno, Roberta Castriconi, Paolo Russo
The aim of this work is the evaluation of the software BreastSimulator, a breast X-ray imaging simulation software as a tool for the creation of 3D uncompressed breast digital models and for the simulation and the optimization of computed tomographic (CT) scanners dedicated to the breast. Eight 3D digital breast phantoms were created with glandular fraction in the range 10% to 68%. The models are characterised by different sizes and modelled realistic anatomical features.. X-ray CT projections were simulated for a dedicated cone-beam CT scanner and reconstructed with the FDK algorithm...
April 11, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28397977/methodological-accuracy-of-image-based-electron-density-assessment-using-dual-energy-computed-tomography
#10
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/28394730/resistance-training-prescription-with-different-load-management-methods-improves-phase-angle-in-older-women
#11
Alex S Ribeiro, Brad J Schoenfeld, Mariana F Souza, Crisieli M Tomeleri, Analiza M Silva, Denílson C Teixeira, Luís B Sardinha, Edilson S Cyrino
The purpose of the present study was to investigate the effect of two different resistance training (RT) prescription methods on phase angle (PA) in older women. Seventy-six older women (68.5 ± 5.7 years) were randomly assigned to one of three groups: two training groups that performed an eight-week RT programme either in a constant load (CT, n = 25) or an ascending pyramidal load (PR, n =  26) routine three times per week, or a control group (CG, n =  25) that performed no exercise. The CT programme consisted of three sets of 8-12 repetition maximum (RM) with a constant load for the three sets, whereas the PR training consisted of three sets of 12/10/8 RM with incremental loads for each set...
April 10, 2017: European Journal of Sport Science
https://www.readbyqxmd.com/read/28376633/virtual-monochromatic-spectral-imaging-for-the-evaluation-of-vertebral-inconspicuous-osteoblastic-metastases-from-lung
#12
Dong Yue, Wang Ru Xin, Chen Jing, Cheng Fan Rong, Sun Li Fei, Liu Ai Lian, Luo Ya Hong
Background The diagnosis of inconspicuous osteoblastic metastases (OBMs) is a challenge in computed tomography (CT) images. The virtual monochromatic spectral (VMS) image of spectral CT is useful for the detection of the low-contrast lesions. Purpose To select the optimal monochromatic level for VMS images of spectral CT for detecting and diagnosing inconspicuous OBMs of the vertebra from lung cancer. Material and Methods Thirty-five patients underwent spectral CT for chest or abdomen. The CT number and standard deviation (SD) of lesions and adjacent normal bone and the SD value of subcutaneous fat were measured on the conventional polychromatic image (140 kVp) and 40-140 keV VMS images...
January 1, 2017: Acta Radiologica
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/28367044/choroidal-thickness-variation-according-to-refractive-error-measured-by-spectral-domain-optical-coherence-tomography-in-korean-children
#14
Geun Young Lee, Sung Yu, Hyun Gu Kang, Jin Seon Kim, Kyoo Won Lee, Jung-Ho Lee
PURPOSE: To assess choroidal thickness (CT) variation according to refractive errors using enhanced-depth imaging optical coherence tomography. METHODS: Eighty-nine eyes (in 89 children) <±6 diopter were categorized into three groups: hyperopia, emmetropia, and myopia, according to refractive error, and underwent choroidal scans using enhanced-depth imaging-optical coherence tomography. CT was measured at the fovea and at 1 mm and 3 mm nasal (N1 and N3), temporal (T1 and T3), superior (S1 and S3), and inferior (I1 and I3) from the fovea...
April 2017: Korean Journal of Ophthalmology: KJO
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
#15
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/28350547/assessment-of-vectorial-total-variation-penalties-on-realistic-dual-energy-ct-data
#16
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
https://www.readbyqxmd.com/read/28345547/contrast-dose-and-radiation-dose-reduction-in-abdominal-enhanced-computerized-tomography-scans-with-single-phase-dual-energy-spectral-computerized-tomography-mode-for-children-with-solid-tumors
#17
Tong Yu, Jun Gao, Zhi-Min Liu, Qi-Feng Zhang, Yong Liu, Ling Jiang, Yun Peng
BACKGROUND: Contrast dose and radiation dose reduction in computerized tomography (CT) scan for adult has been explored successfully, but there have been few studies on the application of low-concentration contrast in pediatric abdominal CT examinations. This was a feasibility study on the use of dual-energy spectral imaging and adaptive statistical iterative reconstruction (ASiR) for the reduction of radiation dose and iodine contrast dose in pediatric abdominal CT patients with solid tumors...
April 5, 2017: Chinese Medical Journal
https://www.readbyqxmd.com/read/28338166/-preoperative-assessment-value-of-spectral-ct-quantitative-parameters-in-lymph-node-metastasis-of-gastric-cancer
#18
Yaru Chai, Jianbo Gao, Jingjing Xing, Peijie Lyu, Pan Liang, Xiaohua Chen
OBJECTIVE: To investigate the preoperative assessment value of spectral CT quantitative parameters in lymph node metastasis of gastric cancer. METHODS: From December 2013 to June 2015, clinical and image data of 86 patients with gastric cancer confirmed by gastroscope pathology undergoing preoperative enhanced CT were prospectively collected. Enhanced CT included nonenhanced CT of conventional 120 kVp mode, arterial phase (AP) and venous phase (VP) with GSI mode on Discover GSI CT scanner...
March 25, 2017: Zhonghua Wei Chang Wai Ke za Zhi, Chinese Journal of Gastrointestinal Surgery
https://www.readbyqxmd.com/read/28332211/a-multi-channel-block-matching-denoising-algorithm-for-spectral-photon-counting-ct-images
#19
Adam P Harrison, Ziyue Xu, David A Bluemke, Amir Pourmorteza, Daniel J Mollura
PURPOSE: We present a denoising algorithm designed for a whole-body prototype photon-counting computed tomography (PCCT) scanner with up to 4 energy thresholds and associated energy-binned images. METHODS: Spectral PCCT images can exhibit low signal to noise ratios (SNRs) due to the limited photon counts in each simultaneously-acquired energy bin. To help address this, our denoising method exploits the correlation and exact alignment between energy bins, adapting the highly-effective block-matching 3D (BM3D) denoising algorithm for PCCT...
March 23, 2017: Medical Physics
https://www.readbyqxmd.com/read/28321168/spectral-computed-tomography-in-advanced-gastric-cancer-can-iodine-concentration-non-invasively-assess-angiogenesis
#20
Xiao-Hua Chen, Ke Ren, Pan Liang, Ya-Ru Chai, Kui-Sheng Chen, Jian-Bo Gao
AIM: To investigate the correlation of iodine concentration (IC) generated by spectral computed tomography (CT) with micro-vessel density (MVD) and vascular endothelial growth factor (VEGF) expression in patients with advanced gastric carcinoma (GC). METHODS: Thirty-four advanced GC patients underwent abdominal enhanced CT in the gemstone spectral imaging mode. The IC of the primary lesion in the arterial phase (AP) and venous phase (VP) were measured, and were then normalized against that in the aorta to provide the normalized IC (nIC)...
March 7, 2017: World Journal of Gastroenterology: WJG
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