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Spectral CT

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https://www.readbyqxmd.com/read/28726669/spectral-performance-of-a-whole-body-research-photon-counting-detector-ct-quantitative-accuracy-in-derived-image-sets
#1
Shuai Leng, Wei Zhou, Zhicong Yu, Ahmed F Halaweish, Bernhard Krauss, Bernhard Schmidt, Lifeng Yu, Steffen Kappler, Cynthia H McCollough
Photon-counting computed tomography (PCCT) uses a photon counting detector to count individual photons and allocate them to specific energy bins by comparing photon energy to preset thresholds. This enables simultaneous multi-energy CT with a single source and detector. Phantom studies were performed to assess the spectral performance of a research PCCT scanner by assessing the accuracy of derived images sets. Specifically, we assessed the accuracy of iodine quantification in iodine map images and of CT number accuracy in virtual monoenergetic images (VMI)...
July 20, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28715327/joint-statistical-iterative-material-image-reconstruction-for-spectral-computed-tomography-using-a-semi-empirical-forward-model
#2
Korbinian Mechlem, Sebastian Ehn, Thorsten Sellerer, Eva Braig, Daniela Munzel, Franz Pfeiffer, Peter B Noel
By acquiring tomographic measurements with several distinct photon energy spectra, spectral computed tomography (spectral CT) is able to provide additional material-specific information compared to conventional CT. This information enables the generation of material selective images, which have found various applications in medical imaging. However, material decomposition typically leads to noise amplification and a degradation of the signal-to-noise ratio. This is still a fundamental problem of spectral CT, especially for low-dose medical applications...
July 13, 2017: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28711211/advanced-tissue-characterization-and-texture-analysis-using-dual-energy-computed-tomography-horizons-and-emerging-applications
#3
REVIEW
Reza Forghani, Ashok Srinivasan, Behzad Forghani
In the last article of this issue, advanced analysis capabilities of DECT is reviewed, including spectral Hounsfield unit attenuation curves, virtual monochromatic images, material decomposition maps, tissue effective Z determination, and other advanced post-processing DECT tools, followed by different methods of analysis of the attenuation curves generated using DECT. The article concludes with exciting future horizons and potential applications, such as the use of the rich quantitative data in dual energy CT scans for texture or radiomic analysis and the use of machine learning methods for generation of prediction models using spectral data...
August 2017: Neuroimaging Clinics of North America
https://www.readbyqxmd.com/read/28711205/dual-energy-computed-tomography-applications-for-the-evaluation-of-cervical-lymphadenopathy
#4
REVIEW
Ahmed M Tawfik, Andreas Michael Bucher, Thomas J Vogl
There is recent interest in the use of dual-energy computed tomography (CT) in head and neck imaging, and the results are encouraging. This article reviews dual-energy CT applications as complementary tools to conventional CT scanning in the evaluation of cervical lymphadenopathy. The article cites the most relevant studies and highlights their results. Single-source and dual-source dual-energy applications including virtual noncontrast images, linear and nonlinear image blending, monochromatic images, iodine quantification, and spectral Hounsfield unit attenuation curve analysis are reviewed...
August 2017: Neuroimaging Clinics of North America
https://www.readbyqxmd.com/read/28711199/dual-energy-computed-tomography-physical-principles-approaches-to-scanning-usage-and-implementation-part-1
#5
REVIEW
Reza Forghani, Bruno De Man, Rajiv Gupta
There are increasing applications of dual-energy computed tomography (CT), a type of spectral CT, in neuroradiology and head and neck imaging. In this 2-part review, the fundamental principles underlying spectral CT scanning and the major considerations in implementing this type of scanning in clinical practice are reviewed. In the first part of this 2-part review, the physical principles underlying spectral CT scanning are reviewed, followed by an overview of the different approaches for spectral CT scanning, including a discussion of the strengths and challenges encountered with each approach...
August 2017: Neuroimaging Clinics of North America
https://www.readbyqxmd.com/read/28708465/synthesis-characterization-redox-behavior-dna-and-protein-binding-and-antibacterial-activity-studies-of-ruthenium-ii-complexes-of-bidentate-schiff-bases
#6
Hena Paul, Buddhadeb Sen, Tapan Kumar Mondal, Pabitra Chattopadhyay
Two new ruthenium(II) complexes of Schiff base ligands (L) derived from cinnamaldehyde and ethylenediamine formulated as [Ru(L)(bpy)2](ClO4)2, where L(1) = N,N'-bis(4-nitrocinnamald-ehyde)ethylenediamine and L(2) = N,N'-bis(2-nitrocinnamaldehyde)-ethylenediamine for complex 1 and 2, respectively, were isolated in pure form. The complexes were characterized by physicochemical and spectroscopic methods. The electrochemical behavior of the complexes showed the Ru(III)/Ru(II) couple at different potentials with quasi-reversible voltammograms...
July 14, 2017: Nucleosides, Nucleotides & Nucleic Acids
https://www.readbyqxmd.com/read/28703886/dual-energy-ct-a-possible-new-method-to-assess-regression-of-rectal-cancers-after-neoadjuvant-treatment
#7
Issam Al-Najami, Henrik C Drue, Robert Steele, Gunnar Baatrup
BACKGROUND AND OBJECTIVES: The measurement of tumor regression after neoadjuvant oncological treatment has gained increasing interest because it has a prognostic value and because it may influence the method of treatment in rectal cancer. The assessment of tumor regression remains difficult and inaccurate with existing methods. Dual Energy Computed Tomography (DECT) enables qualitative tissue differentiation by simultaneous scanning with different levels of energy. We aimed to assess the feasibility of DECT in quantifying tumor response to neoadjuvant therapy in loco-advanced rectal cancer...
July 13, 2017: Journal of Surgical Oncology
https://www.readbyqxmd.com/read/28687219/diabetic-macular-edema-with-and-without-subfoveal-neuroretinal-detachment-two-different-morphological-and-functional-entities
#8
Stela Vujosevic, Tommaso Torresin, Marianna Berton, Silvia Bini, Enrica Convento, Edoardo Midena
PURPOSE: To assess specific morphologic and functional characteristics in eyes with diabetic macular edema (DME) with subfoveal neuroretinal detachment (SND+) vs DME without SND (SND-). DESIGN: Cross-sectional, prospective, comparative case series. METHODS: Seventy two patients (72 eyes: 22 eyes SND+ and 50 eyes SND-) with treatment-naïve, center-involving DME were evaluated. Data gathering included fundus color photographs, fluorescein angiography, spectral-domain optical coherence tomography (SD-OCT), best corrected visual acuity (BCVA), and microperimetry...
July 4, 2017: American Journal of Ophthalmology
https://www.readbyqxmd.com/read/28686423/nanoparticle-uptake-in-plants-gold-nanomaterial-localized-in-roots-of-arabidopsis-thaliana-by-x-ray-computed-nanotomography-and-hyperspectral-imaging
#9
Astrid Avellan, Fabienne Schwab, Armand Masion, Perrine Chaurand, Daniel Borschneck, Vladimir Vidal, Jérôme Rose, Catherine Santaella, Clément Levard
Terrestrial plants can internalize and translocate nanoparticles (NPs). However, direct evidence for the processes driving the NP uptake and distribution in plants is scarce at the cellular level. Here, NP-root interactions were investigated after 10 days of exposure of Arabidopsis thaliana to 10 mg·L(-1) of negatively or positively charged gold NPs (∼12 nm) in gels. Two complementary imaging tools were used: X-ray computed nanotomography (nano-CT) and enhanced dark-field microscopy combined with hyperspectral imaging (DF-HSI)...
July 20, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28684998/bioactive-m-ii-complexes-of-amino-acid-based-n3o-donor-mixed-ligand-in-vitro-and-in-silico-dna-binding-studies
#10
T Daniel Prakash, V Violet Dhayabaran
Three novel mixed ligand M(II) complexes, namely [CoL(1)L(2)Cl2] (1), [CuL(1)L(2)Cl2] (2), and [ZnL(1)L(2)Cl2] (3), were synthesized using 1,4-naphthoquinone, L-histidine, and 1,10-phenanthroline as ligands. The ligand framework and the corresponding structural changes on complexation were ascertained based on the results of elemental analysis, conductivity measurements, magnetic behavior, FT-IR, UV-visible, (1)H NMR, (13)C NMR, ESR spectral studies, and ESI mass spectrometry. The biological action of the ligand (L) and complexes 1-3 such as DNA binding and cleaving ability were studied...
July 2017: Journal of Chemical Biology
https://www.readbyqxmd.com/read/28684756/multicolor-spectral-photon-counting-computed-tomography-in-vivo-dual-contrast-imaging-with-a-high-count-rate-scanner
#11
David P Cormode, Salim Si-Mohamed, Daniel Bar-Ness, Monica Sigovan, Pratap C Naha, Joelle Balegamire, Franck Lavenne, Philippe Coulon, Ewald Roessl, Matthias Bartels, Michal Rokni, Ira Blevis, Loic Boussel, Philippe Douek
A new prototype spectral photon-counting computed tomography (SPCCT) based on a modified clinical CT system has been developed. SPCCT analysis of the energy composition of the transmitted x-ray spectrum potentially allows simultaneous dual contrast agent imaging, however, this has not yet been demonstrated with such a system. We investigated the feasibility of using this system to distinguish gold nanoparticles (AuNP) and an iodinated contrast agent. The contrast agents and calcium phosphate were imaged in phantoms...
July 6, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28683124/hybrid-spectral-ct-reconstruction
#12
Darin P Clark, Cristian T Badea
Current photon counting x-ray detector (PCD) technology faces limitations associated with spectral fidelity and photon starvation. One strategy for addressing these limitations is to supplement PCD data with high-resolution, low-noise data acquired with an energy-integrating detector (EID). In this work, we propose an iterative, hybrid reconstruction technique which combines the spectral properties of PCD data with the resolution and signal-to-noise characteristics of EID data. Our hybrid reconstruction technique is based on an algebraic model of data fidelity which substitutes the EID data into the data fidelity term associated with the PCD reconstruction, resulting in a joint reconstruction problem...
2017: PloS One
https://www.readbyqxmd.com/read/28681402/effects-of-calibration-methods-on-quantitative-material-decomposition-in-photon-counting-spectral-computed-tomography-using-a-maximum-a-posteriori-estimator
#13
Tyler E Curtis, Ryan K Roeder
PURPOSE: Advances in photon-counting detectors have enabled quantitative material decomposition using multi-energy or spectral computed tomography (CT). Supervised methods for material decomposition utilize an estimated attenuation for each material of interest at each photon energy level, which must be calibrated based upon calculated or measured values for known compositions. Measurements using a calibration phantom can advantageously account for system specific noise, but the effect of calibration methods on the material basis matrix and subsequent quantitative material decomposition has not been experimentally investigated...
July 6, 2017: Medical Physics
https://www.readbyqxmd.com/read/28677062/the-effects-of-iodine-attenuation-on-pulmonary-nodule-volumetry-using-novel-dual-layer-computed-tomography-reconstructions
#14
A M den Harder, F Bangert, R W van Hamersvelt, T Leiner, Julien Milles, A M R Schilham, M J Willemink, P A de Jong
OBJECTIVES: To assess the effect of iodine attenuation on pulmonary nodule volumetry using virtual non-contrast (VNC) and mono-energetic reconstructions. METHODS: A consecutive series of patients who underwent a contrast-enhanced chest CT scan were included. Images were acquired on a novel dual-layer spectral CT system. Conventional reconstructions as well as VNC and mono-energetic images at different keV levels were used for nodule volumetry. RESULTS: Twenty-four patients with a total of 63 nodules were included...
July 4, 2017: European Radiology
https://www.readbyqxmd.com/read/28677003/poly-energetic-and-virtual-mono-energetic-images-from-a-novel-dual-layer-spectral-detector-ct-optimization-of-window-settings-is-crucial-to-improve-subjective-image-quality-in-abdominal-ct-angiographies
#15
Jonas Doerner, Julian A Luetkens, Andra-Iza Iuga, Jonathan Byrtus, Stefan Haneder, David Maintz, Tilman Hickethier
PURPOSE: We aimed to determine optimal window settings for poly-energetic (PolyE) and virtual mono-energetic images (MonoE) derived from abdominal angiographic studies on a novel dual-layer spectral detector CT (SDCT) system. METHODS: From 50 patients, SDCT datasets PolyE and MonoE at 70 and 40 keV levels were reconstructed and best individual window width and level (BI-W/L) manually assessed. Through regression analysis, the so-called optimized individual (OI-W/L) values were obtained...
July 4, 2017: Abdominal Radiology
https://www.readbyqxmd.com/read/28673603/abdominal-applications-of-a-novel-detector-based-spectral-ct
#16
REVIEW
Nicholas Fulton, Prabhakar Rajiah
Detector-based spectral computed tomography (SDCT) is a recently introduced technology that uses a single x-ray tube and 2 layers of detectors to simultaneously collect low- and high-energy data. In this article, we provide an overview of this novel SDCT technology in abdominal imaging. Several applications of SDCT in abdominal imaging are discussed and illustrated, along with a brief description of current literature on the status of dual-energy computed tomography in these applications. This includes urinary calculus composition, characterization of masses (renal, adrenal, hepatic, and others), tumor perfusion, improving vascular contrast, improving lesion conspicuity, decreasing artifacts, and reducing radiation dose...
May 17, 2017: Current Problems in Diagnostic Radiology
https://www.readbyqxmd.com/read/28668431/image-quality-evaluation-of-dual-layer-spectral-detector-ct-of-the-chest-and-comparison-with-conventional-ct-imaging
#17
Jonas Doerner, Myriam Hauger, Tilman Hickethier, Jonathan Byrtus, Christian Wybranski, Nils Große Hokamp, David Maintz, Stefan Haneder
OBJECTIVES: To evaluate image quality parameters of virtual mono-energetic (MonoE) and conventional (CR) imaging derived from a dual-layer spectral detector CT (DLCT) in oncological follow-up venous phase imaging of the chest and comparison with conventional multi-detector CT (CRMDCT) imaging. MATERIALS AND METHODS: A total of 55 patients who had oncologic staging with conventional CT and DLCT of the chest in venous phase were included in this study. Established image quality parameters were derived from all datasets in defined thoracic landmarks...
August 2017: European Journal of Radiology
https://www.readbyqxmd.com/read/28658505/fast-kvp-switching-dual-energy-contrast-enhanced-thorax-and-cardiac-ct-a-phantom-study-on-the-accuracy-of-iodine-concentration-and-effective-atomic-number-measurement
#18
Antonios E Papadakis, John Damilakis
PURPOSE: To assess the effect of vessel diameter and exposure parameters on the estimation accuracy of concentration and effective atomic number (Zeff ) of iodine (I) in contrast-enhanced thorax and cardiac dual-energy CT using a modern fast kVp-switching CT scanner. METHODS: A standard semi-anthropomorphic cardiac CT phantom devised to simulate the human chest at three different body habitus i.e. medium-sized, large-sized, and obese, was scanned using a fast kVp-switching Revolution-GSI GE CT scanner...
June 28, 2017: Medical Physics
https://www.readbyqxmd.com/read/28657201/comparison-of-low-and-ultra-low-dose-computed-tomography-protocols-for-quantitative-lung-and-airway-assessment
#19
Emily Hammond, Chelsea Sloan, John D Newell, Jered P Sieren, Melissa Saylor, Craig Vidal, Shayna Hogue, Frank De Stefano, Alexa Sieren, Eric A Hoffman, Jessica C Sieren
PURPOSE: Quantitative computed tomography (CT) measures are increasingly being developed and used to characterize lung disease. With recent advances in CT technologies, we sought to evaluate the quantitative accuracy of lung imaging at low and ultra-low radiation doses with the use of iterative reconstruction (IR), tube current modulation (TCM), and spectral shaping. METHODS: We investigated the effect of five independent CT protocols reconstructed with IR on quantitative airway measures and global lung measures using an in-vivo large animal model as a human subject surrogate...
June 28, 2017: Medical Physics
https://www.readbyqxmd.com/read/28648922/oxovanadium-iv-complexes-with-knoevenagel-schiff-base-condensate-as-impending-chemotherapeutic-agents-synthesis-characterization-biological-screening-and-anti-proliferative-assay
#20
Rajakkani Paulpandiyan, Natarajan Raman
Two novel oxovanadium(IV) complexes [VOL1]SO4(1) and [VOL2]SO4(2) containing Knoevenagel condensate Schiff base ligand (L1/L2) have been synthesized and characterized by physical, spectral and analytical methods. These complexes are reported as ionic in nature on the basis of elemental composition and molar conductance, and possess square pyramidal geometry around the central metal ions. The binding interactions of (1) and (2) with calf thymus DNA (CT DNA) were explored by absorption spectrophotometric titration, cyclic voltammetry data and viscosity measurements...
June 19, 2017: Bioorganic Chemistry
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