188 results match your criteria attenuation metric

Estimating evolutionary changes between highly passaged and original parental lumpy skin disease virus strains.

Transbound Emerg Dis 2021 Sep 23. Epub 2021 Sep 23.

Federal Center for Animal Health, Vladimir, 600901, Russia.

Research into the phylogenetic relationships of lumpy skin disease virus (LSDV) strains was long overlooked, partially due to its original restricted distribution to sub-Saharan Africa. However, recent incursions into northern latitudes, and a rapid spread causing major economic losses worldwide, have intensified additional research on the disease and the causative virus. This study delineates the phylogeny of LSDV in the context of full genome sequences of strains recovered in the field, as well as strains highly passaged in cell culture. Read More

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September 2021

Laboratory Evaluation of Shell Add-On Products for American Football Helmets for Professional Linemen.

Ann Biomed Eng 2021 Aug 10. Epub 2021 Aug 10.

Center for Injury Research and Prevention, Children's Hospital of Philadelphia, Philadelphia, PA, USA.

The Guardian Cap NXT (GC NXT) and the ProTech Helmet Cap (ProTech) are commercially available aftermarket products designed to augment the energy attenuation characteristics of American football helmets. The ability of these helmet shell add-on products to mitigate the severity of impacts typically experienced by professional offensive and defensive linemen was evaluated for seven helmet models using two test series. In linear impactor tests, the GC NXT reduced head impact severity as measured by the head acceleration response metric (HARM) by 9% relative to the helmets only, while the ProTech reduced HARM by 5%. Read More

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Dynamic cardiac PET motion correction using 3D normalized gradient fields in patients and phantom simulations.

Med Phys 2021 Sep 20;48(9):5072-5084. Epub 2021 Jul 20.

Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, USA.

This work expands on the implementation of three-dimensional (3D) normalized gradient fields to correct for whole-body motion and cardiac creep in [N-13]-ammonia patient studies and evaluates its accuracy using a dynamic phantom simulation model.

Methods: A full rigid-body algorithm was developed using 3D normalized gradient fields including a multi-resolution step and sampling off the voxel grid to reduce interpolation artifacts. Optimization was performed using a weighted similarity metric that accounts for opposing gradients between images of blood pool and perfused tissue without the need for segmentation. Read More

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September 2021

Feasibility of attenuation map alignment in pinhole cardiac SPECT using exponential data consistency conditions.

Med Phys 2021 Sep 21;48(9):4955-4965. Epub 2021 Jul 21.

Univ. Grenoble Alpes, CNRS, Grenoble INP, TIMC, Grenoble, France.

Purpose: Dedicated cardiac SPECT systems do not typically include an integrated CT scanner and thus attenuation correction requires registration of separately acquired transmission scans. Data consistency conditions are equations that express the redundancy between projections while taking into account the attenuation effects. This study assessed the feasibility of applying exponential data consistency conditions to rebinned pinhole projections for attenuation-map registration in pinhole cardiac SPECT. Read More

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September 2021

A methodology to estimate the patient diameter and thickness from thoracic and abdominal projection radiographs of adult patients.

Phys Med Biol 2021 Jul 7;66(14). Epub 2021 Jul 7.

Department of Imaging and Pathology, Division of Medical Physics and Quality Assessment, University of Leuven, Leuven, B-3000, Belgium.

Patient dose management systems can be part of a department's quality management tools to estimate items such as the radiation burden in specific groups or list dose outliers for further follow up. Patient size information could improve both aspects, but is not generally available. A new metric is proposed to estimate patient size for thorax and abdominal projection radiography from parameters available in thedicomheader and therefore accessible by dose management software. Read More

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Human coronary inflammation by computed tomography: Relationship with coronary microvascular dysfunction.

Int J Cardiol 2021 08 28;336:8-13. Epub 2021 May 28.

Cardiology Department, Parma University Hospital, Parma, Italy. Electronic address:

Background A new imaging metric using coronary computed tomography angiography (CCTA), addressing the peri-coronary adipose tissue (PCAT) computed tomography (CT) attenuation, has been clinically validated. This method provides information regarding coronary inflammation. It is unclear how coronary inflammation affects microvascular function. Read More

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Imitation learning for improved 3D PET/MR attenuation correction.

Med Image Anal 2021 07 16;71:102079. Epub 2021 Apr 16.

School of Biomedical Engineering & Imaging Sciences, King's College London, London SE1 7EH, UK.

The assessment of the quality of synthesised/pseudo Computed Tomography (pCT) images is commonly measured by an intensity-wise similarity between the ground truth CT and the pCT. However, when using the pCT as an attenuation map (μ-map) for PET reconstruction in Positron Emission Tomography Magnetic Resonance Imaging (PET/MRI) minimising the error between pCT and CT neglects the main objective of predicting a pCT that when used as μ-map reconstructs a pseudo PET (pPET) which is as similar as possible to the gold standard CT-derived PET reconstruction. This observation motivated us to propose a novel multi-hypothesis deep learning framework explicitly aimed at PET reconstruction application. Read More

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A comparison of breast and lung doses from chest CT scans using organ-based tube current modulation (OBTCM) vs. Automatic tube current modulation (ATCM).

J Appl Clin Med Phys 2021 May 3;22(5):97-109. Epub 2021 May 3.

Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, USA.

Purpose: The purpose of this work was to estimate and compare breast and lung doses of chest CT scans using organ-based tube current modulation (OBTCM) to those from conventional, attenuation-based automatic tube current modulation (ATCM) across a range of patient sizes.

Methods: Thirty-four patients (17 females, 17 males) who underwent clinically indicated CT chest/abdomen/pelvis (CAP) examinations employing OBTCM were collected from two multi-detector row CT scanners. Patient size metric was assessed as water equivalent diameter (D ) taken at the center of the scan volume. Read More

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Machine learning automatically detects COVID-19 using chest CTs in a large multicenter cohort.

Eur Radiol 2021 May 1. Epub 2021 May 1.

Siemens Healthineers, Princeton, NJ, USA.

Objectives: To investigate machine learning classifiers and interpretable models using chest CT for detection of COVID-19 and differentiation from other pneumonias, interstitial lung disease (ILD) and normal CTs.

Methods: Our retrospective multi-institutional study obtained 2446 chest CTs from 16 institutions (including 1161 COVID-19 patients). Training/validation/testing cohorts included 1011/50/100 COVID-19, 388/16/33 ILD, 189/16/33 other pneumonias, and 559/17/34 normal (no pathologies) CTs. Read More

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Chemo-metrically formulated consortium with selectively screened bacterial strains for ameliorated biotransformation and detoxification of 1,4-dioxane.

J Hazard Mater 2021 07 17;413:125456. Epub 2021 Feb 17.

Analytical and Environmental Science Division & Centralized Instrument Facility, CSIR-Central Salt & Marine Chemicals Research Institute, Bhavnagar 364 002, Gujarat, India; Academy of Scientific and Innovative Research, Ghaziabad 201 002, Uttar Pradesh, India. Electronic address:

The biotransformation of 1,4-dioxane, a endrocrine disrupting chemical was achieved using different bacterial strains and their consortia. Three different bacterial isolates were screened on their ability to grow with 50 mg/L 1,4-dioxane in the basal mineral medium. Then the isolates were tested for its efficiency to biotransform 1000 mg/L 1,4-dioxane at varying period of time; 24-120 h. Read More

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Cardiovascular risk stratification by coronary computed tomography angiography imaging: current state-of-the-art.

Eur J Prev Cardiol 2021 Apr 30. Epub 2021 Apr 30.

1st Department of Cardiology, Hippokration Hospital, National and Kapodistrian University of Athens, 114 Vas. Sofias Avenue, 11527, Athens, Greece.

Current cardiovascular risk stratification by use of clinical risk score systems or plasma biomarkers is good but less than satisfactory in identifying patients at residual risk for coronary events. Recent clinical evidence puts now further emphasis on the role of coronary anatomy assessment by coronary computed tomography angiography (CCTA) for the management of patients with stable ischaemic heart disease. Available computed tomography (CT) technology allows the quantification of plaque burden, identification of high-risk plaques, or the functional assessment of coronary lesions for ischaemia detection and revascularization for refractory angina symptoms. Read More

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Can ultrasound attenuation measurement be used to characterise grain statistics in castings?

Ultrasonics 2021 Aug 15;115:106441. Epub 2021 Apr 15.

EDF Lab Les Renardières, EDF R&D, Avenue des Renardières, 77818 Moret-sur-Loing, France.

Industrial inspection protocols are qualified using mock-ups manufactured according to the same procedure as the plant part. For coarse-grained castings, known for their low inspectability, relying on mock-ups becomes particularly challenging owing to the variability of grain properties among components. Consequently, there is a keen interest in the capability to verify whether the grain size of the component under test matches the qualification specification in-situ. Read More

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Empirical method for rapid quantification of intrinsic fluorescence signals of key metabolic probes from optical spectra measured on tissue-mimicking turbid medium.

J Biomed Opt 2021 04;26(4)

Univ. of Kentucky, United States.

Significance: Optical fluorescence spectroscopy technique has been explored extensively to quantify both glucose uptake and mitochondrial metabolism with proper fluorescent probes in small tumor models in vivo. However, it remains a great challenge to rapidly quantify the intrinsic metabolic fluorophores from the optically measured fluorescence spectra that contain significant distortions due to tissue absorption and scattering.

Aim: To enable rapid spectral data processing and quantify the in vivo metabolic parameters in real-time, we present an empirical ratio-metric method for rapid fluorescence spectra attenuation correction with high accuracy. Read More

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A novel calibration for L-shell x-ray fluorescence measurements of bone lead concentration using the strontium K/Kratio.

Physiol Meas 2021 05 14;42(4). Epub 2021 May 14.

Department of Physics, California State University, Fresno, Fresno, CA, United States of America.

. Lead (Pb) is a well-known toxic element.bone Pb concentration measurement is a long-term exposure metric complementary to blood Pb concentration measurement which is a metric of recent exposure. Read More

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The impact of CT image parameters and skull heterogeneity modeling on the accuracy of transcranial focused ultrasound simulations.

J Neural Eng 2021 05 4;18(4). Epub 2021 May 4.

Foundation for Research on Information Technologies in Society (IT'IS), Zurich, Switzerland.

. Low-intensity transcranial ultrasound stimulation (TUS) is a promising non-invasive brain stimulation (NIBS) technique. TUS can reach deeper areas and target smaller regions in the brain than other NIBS techniques, but its application in humans is hampered by the lack of a straightforward and reliable procedure to predict the induced ultrasound exposure. Read More

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Learning ultrasound rendering from cross-sectional model slices for simulated training.

Int J Comput Assist Radiol Surg 2021 May 8;16(5):721-730. Epub 2021 Apr 8.

Computer-assisted Applications in Medicine, ETH Zurich, Zürich, Switzerland.

Purpose: Given the high level of expertise required for navigation and interpretation of ultrasound images, computational simulations can facilitate the training of such skills in virtual reality. With ray-tracing based simulations, realistic ultrasound images can be generated. However, due to computational constraints for interactivity, image quality typically needs to be compromised. Read More

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Attenuation correction using deep learning for brain perfusion SPECT images.

Ann Nucl Med 2021 May 9;35(5):589-599. Epub 2021 Mar 9.

Division of Positron Emission Tomography, Institute of Advanced Clinical Medicine, Kindai University, Osaka, 589-8511, Japan.

Objective: Non-uniform attenuation correction using computed tomography (CT) improves the image quality and quantification of single-photon emission computed tomography (SPECT). However, it is not widely used because it requires a SPECT/CT scanner. This study constructs a convolutional neural network (CNN) to generate attenuation-corrected SPECT images directly from non-attenuation-corrected SPECT images. Read More

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Accuracy Assessment of SUV Measurements in SPECT/CT: A Phantom Study.

J Nucl Med Technol 2021 Sep 15;49(3):250-255. Epub 2021 Mar 15.

Oncological and Radiological Science Cluster, Advanced Medical and Dental Institute, [email protected], Universiti Sains Malaysia, Penang, Malaysia;

Advances in iterative image reconstruction enable absolute quantification of SPECT/CT studies by incorporating compensations for collimator-detector response, attenuation, and scatter. This study aimed to assess the quantitative accuracy of SPECT/CT based on different levels of Tc activity (low/high) using different SUV metrics (SUV, SUV, SUV, and SUV [the average values that include pixels greater than 60% and 75% of the SUV in the volume of interest, respectively]). A Jaszczak phantom equipped with 6 fillable spheres was set up with low and high activity ratios of 1:4 and 1:10 (background-to-sphere) on background activities of 10 and 60 kBq/mL, respectively. Read More

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September 2021

Resveratrol-mediated attenuation of superantigen-driven acute respiratory distress syndrome is mediated by microbiota in the lungs and gut.

Pharmacol Res 2021 05 15;167:105548. Epub 2021 Mar 15.

Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, SC 29208, USA. Electronic address:

Acute Respiratory Distress Syndrome (ARDS) is triggered by a variety of agents, including Staphylococcal Enterotoxin B (SEB). Interestingly, a significant proportion of patients with COVID-19, also develop ARDS. In the absence of effective treatments, ARDS results in almost 40% mortality. Read More

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Feasibility of Deep Learning-Guided Attenuation and Scatter Correction of Whole-Body 68Ga-PSMA PET Studies in the Image Domain.

Clin Nucl Med 2021 Aug;46(8):609-615

Division of Nuclear Medicine and Molecular Imaging, Department of Medical Imaging, Geneva University Hospital, CH-1211 Geneva 4.

Objective: This study evaluates the feasibility of direct scatter and attenuation correction of whole-body 68Ga-PSMA PET images in the image domain using deep learning.

Methods: Whole-body 68Ga-PSMA PET images of 399 subjects were used to train a residual deep learning model, taking PET non-attenuation-corrected images (PET-nonAC) as input and CT-based attenuation-corrected PET images (PET-CTAC) as target (reference). Forty-six whole-body 68Ga-PSMA PET images were used as an independent validation dataset. Read More

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Impact-induced cartilage damage assessed using polarisation-sensitive optical coherence tomography.

J Mech Behav Biomed Mater 2021 05 13;117:104326. Epub 2021 Jan 13.

The Dodd-Walls Centre for Photonic and Quantum Technologies, Department of Physics, The University of Auckland, Auckland, 1010, New Zealand.

Non-invasive determination of structural changes in articular cartilage immediately after impact and rehydration provides insight into the response and recovery of the soft tissue, as well as provides a potential methodology for clinicians to quantify early degenerative changes. In this study, we use polarisation-sensitive optical coherence tomography (PS-OCT) to examine subtle alterations of the optical properties in healthy and early-stage degenerate articular cartilage immediately after impact loading to identify structurally relevant metrics required for understanding the mechanical factors of osteoarthritic initiation and progression. A custom-designed impact testing rig was used to deliver 0. Read More

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Adherence to Ideal Cardiovascular Health Metrics Is Associated With Reduced Odds of Hepatic Steatosis.

Hepatol Commun 2021 01 10;5(1):74-82. Epub 2020 Oct 10.

Section of Gastroenterology Boston Medical Center Boston University School of Medicine Boston MA US.

The American Heart Association (AHA) introduced Life's Simple 7 as a metric to define ideal cardiovascular health. We examined the association between cardiovascular health score (CHS) and prevalent nonalcoholic fatty liver disease (NAFLD) among Framingham Heart Study participants with varying genetic risk of NAFLD. Framingham Heart Study participants who underwent abdominal computed tomography scans were included (n = 2,773). Read More

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January 2021

Efficacy of endotracheal tube suctioning in intubated intensive care unit patients determined by catheter-based optical coherence tomography-a pilot study.

Quant Imaging Med Surg 2021 Jan;11(1):1-8

Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.

Background: Mechanical ventilation using an endotracheal tube (ETT) is one of the critical interventions given to patients in the intensive care unit (ICU). ETTs are associated with the formation of biofilms, placing patients at increased risk for developing ventilator-associated pneumonia (VAP). ETT suctioning is used to remove secretions, reduce bacterial colonization, and reduce the rate of biofilm formation. Read More

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January 2021

Association of quantitative CT lung density measurements and lung function decline in World Trade Center workers.

Clin Respir J 2021 Jun 29;15(6):613-621. Epub 2020 Dec 29.

Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY, USA.

Background: Occupational exposures at the WTC site after 11 September 2001 have been associated with presumably inflammatory chronic lower airway diseases.

Aims: In this study, we describe the trajectories of expiratory air flow decline, identify subgroups with adverse progression, and investigate the association of those trajectories with quantitative computed tomography (QCT) imaging measurement of increased and decreased lung density.

Methods: We examined the trajectories of expiratory air flow decline in a group of 1,321 former WTC workers and volunteers with at least three periodic spirometries, and using QCT-measured low (LAV%, -950 HU) and high (HAV%, from -600 to -250 HU) attenuation volume percent. Read More

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Single Image Dehazing Algorithm Analysis with Hyperspectral Images in the Visible Range.

Sensors (Basel) 2020 Nov 23;20(22). Epub 2020 Nov 23.

Department of Optics, Faculty of Science, University of Granada, 18071 Granada, Spain.

In foggy or hazy conditions, images are degraded due to the scattering and attenuation of atmospheric particles, reducing the contrast and visibility and changing the color. This degradation depends on the distance, the density of the atmospheric particles and the wavelength. We have tested and applied five single image dehazing algorithms, originally developed to work on RGB images and not requiring user interaction and/or prior knowledge about the images, on a spectral hazy image database in the visible range. Read More

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November 2020

Elastic guided waves in helical multi-wire armors.

Ultrasonics 2021 Feb 9;110:106294. Epub 2020 Nov 9.

LHEAA, UMR CNRS 6598, Centrale Nantes, F-44321 Nantes, France.

In this paper, a numerical method is proposed to investigate the propagation of elastic guided waves in the armors protecting cylindrical structures, such as cables and pipes, and evaluate the feasibility of using these waves in the context of non-destructive evaluation and structural health monitoring. Armors usually consist of a large number of helical wires in contact with polymeric sheaths surrounding the structure. The numerical method combines a semi-analytical finite element method written in twisting coordinates, which accounts for the continuous screw symmetry of the problem along the structure axis, with rotational Bloch conditions in the cross-section in order to account for the high order of the discrete circular symmetry. Read More

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February 2021

Oxygen-Deficient Bimetallic Oxide FeWO Nanosheets as Peroxidase-Like Nanozyme for Sensing Cancer via Photoacoustic Imaging.

Small 2020 11 26;16(46):e2003496. Epub 2020 Oct 26.

Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, 215123, China.

Nanozymes with high catalytic activity and great stability have attracted increasing interests as the promising alternative to natural enzymes for applications in various fields. In this study, a new type of highly efficient peroxidase-like nanozymes based on FeWO nanosheets (NSs) synthesized by a thermal-decomposition method is reported. Owing to the sheet-structure with maximized utilization of catalytic sites (Fe atoms and oxygen vacancies), such FeWO NSs exert efficient enzyme activity to trigger catalytic decomposition of hydrogen peroxide (H O ) into hydroxyl radicals (•OH). Read More

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November 2020

Efficacy of inhibitory control depends on procrastination and deceleration in saccade planning.

Exp Brain Res 2020 Oct 9;238(10):2417-2432. Epub 2020 Aug 9.

Centre of Behavioural and Cognitive Sciences, University of Allahabad (Senate Hall Campus), Prayagraj, Uttar Pradesh, 211002, India.

A goal-directed flexible behavior warrants our ability to timely inhibit impending movements deemed inappropriate due to an abrupt change in the context. Race model of countermanding rapid saccadic eye movement posits a competition between a preparatory GO process and an inhibitory STOP process rising to reach a fixed threshold. Stop-signal response time (SSRT), which is the average time STOP takes to rise to the threshold, is widely used as a metric to assess the ability to revoke a movement. Read More

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October 2020

Relative Ectopic Kidney Function Quantification Using DMSA Tomoscintigraphy Modality.

J Healthc Eng 2020 26;2020:6092305. Epub 2020 May 26.

Advanced Technologies for Medicine and Signals (ATMS), Sfax, Tunisia.

The ectopic renal function estimation based on a manual region of interest (ROI) extraction could be considered as time consuming. It could also affect the clinical interpretation and thus deviate the therapeutic attitude. For this purpose, we propose an advanced tool to evaluate such function through the dimercaptosuccinic acid (DMSA) kidney scintigraphy scans. Read More

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Skin dose in chest wall radiotherapy with bolus: a Monte Carlo study.

Phys Med Biol 2020 08 11;65(15):155016. Epub 2020 Aug 11.

Dept. of Medical Physics, Nova Scotia Health Authority, Halifax, B3H 1V7 Canada.

Monte Carlo simulations are used to investigate skin dose resulting from chest wall radiotherapy with bolus. A simple model of a female thorax is developed, which includes a 2 mm-thick skin layer. Two representative 6 MV source models are considered: a tangents source model consisting of a parallel opposed pair of medial and lateral fields and subfields, and an arc source model. Read More

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