keyword
MENU ▼
Read by QxMD icon Read
search

High-density 3D mapping

keyword
https://www.readbyqxmd.com/read/28436918/an-integrated-and-highly-sensitive-ultrafast-acoustoelectric-imaging-system-for-biomedical-applications
#1
Beatrice Berthon, Pierre-Marc Dansette, Mickael Tanter, Mathieu Pernot, Jean Provost
PURPOSE: Direct imaging of cardiac electrical activation is crucial to better understand and diagnose diseases linked to arrhythmias. This work presents an Ultrafast Acoustoelectric Imaging (UAI) system for direct and non-invasive ultrafast mapping of propagating current densities. MATERIALS AND METHODS: Acoustoelectric imaging is based on the acoustoelectric effect, the modulation of the medium's electrical impedance by a propagating ultrasonic wave. UAI triggers this effect with plane wave emissions to image current densities...
April 24, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28416035/measuring-the-autocorrelation-function-of-nanoscale-three-dimensional-density-distribution-in-individual-cells-using-scanning-transmission-electron-microscopy-atomic-force-microscopy-and-a-new-deconvolution-algorithm
#2
Yue Li, Di Zhang, Ilker Capoglu, Karl A Hujsak, Dhwanil Damania, Lusik Cherkezyan, Eric Roth, Reiner Bleher, Jinsong S Wu, Hariharan Subramanian, Vinayak P Dravid, Vadim Backman
Essentially all biological processes are highly dependent on the nanoscale architecture of the cellular components where these processes take place. Statistical measures, such as the autocorrelation function (ACF) of the three-dimensional (3D) mass-density distribution, are widely used to characterize cellular nanostructure. However, conventional methods of reconstruction of the deterministic 3D mass-density distribution, from which these statistical measures can be calculated, have been inadequate for thick biological structures, such as whole cells, due to the conflict between the need for nanoscale resolution and its inverse relationship with thickness after conventional tomographic reconstruction...
April 18, 2017: Microscopy and Microanalysis
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
#3
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/28407062/voltage-gradient-mapping-and-electrophysiologically-guided-cryoablation-in-children-with-avnrt
#4
Fabrizio Drago, Irma Battipaglia, Mario Salvatore Russo, Romolo Remoli, Vincenzo Pazzano, Gino Grifoni, Greta Allegretti, Massimo Stefano Silvetti
Aims: Recently, voltage gradient mapping of Koch's triangle to find low-voltage connections, or 'voltage bridges', corresponding to the anatomic position of the slow pathway, has been introduced as a method to ablate atrioventricular nodal reentry tachycardia (AVNRT) in children. Thus, we aimed to assess the effectiveness of voltage mapping of Koch's triangle, combined with the search for the slow potential signal in 'low-voltage bridges', to guide cryoablation of AVNRT in children. Methods and results: From June 2015 to May 2016, 35 consecutive paediatric patients (mean age 12...
April 12, 2017: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/28401432/feasibility-assessment-of-a-maldi-fticr-imaging-approach-for-the-3d-reconstruction-of-a-mouse-lung
#5
E Ellen Jones, Cristine Quiason, Stephanie Dale, Sheerin K Shahidi-Latham
Matrix assisted laser desorption ionization imaging mass spectrometry (MALDI IMS) has proven to be a quick, robust, and label-free tool to produce two-dimensional (2D) ion-density maps representing the distribution of a variety of analytes across a tissue section of interest. In addition, three-dimensional (3D) imaging mass spectrometry workflows have been developed that are capable of visualizing these same analytes throughout an entire volume of a tissue rather than a single cross-section. Until recently, the use of Fourier transform ion cyclotron resonance (FTICR) mass spectrometers for 3D volume reconstruction has been impractical due to software limitations, such as inadequate capacity to manipulate the extremely large data files produced during an imaging experiment...
April 11, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28388052/mapping-charge-distribution-in-single-pbs-core-cds-arm-nano-multipod-heterostructures-by-off-axis-electron-holography
#6
Rajesh Chalasani, Alexander Pekin, Alexander Rabkin, Ran E Abutbul, Oswaldo Diéguez, Yaron Kauffmann, Yuval Golan, Amit Kohn
We synthesized PbS core-CdS arm nanomultipod heterostructures (NMHs) that exhibit PbS{111}/CdS{0002} epitaxial relations. The PbS-CdS interface is chemically sharp as determined by aberration corrected transmission electron microscopy (TEM) and compared to density functional theory (DFT) calculations. Ensemble fluorescence measurements show quenching of the optical signal from the CdS arms indicating charge separation due to the heterojunction with PbS. A finite-element three-dimensional (3D) calculation of the Poisson equation shows a type-I heterojunction, which would prevent recombination in the CdS arm after optical excitation...
April 13, 2017: Nano Letters
https://www.readbyqxmd.com/read/28306555/assessment-of-dosimetric-impact-of-system-specific-geometric-distortion-in-an-mri-only-based-radiotherapy-workflow-for-prostate
#7
C Gustafsson, F Nordström, E Persson, J Brynolfsson, L E Olsson
Dosimetric errors in a magnetic resonance imaging (MRI) only radiotherapy workflow may be caused by system specific geometric distortion from MRI. The aim of this study was to evaluate the impact on planned dose distribution and delineated structures for prostate patients, originating from this distortion. A method was developed, in which computer tomography (CT) images were distorted using the MRI distortion field. The displacement map for an optimized MRI treatment planning sequence was measured using a dedicated phantom in a 3 T MRI system...
April 21, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28282453/the-use-of-a-novel-signal-analysis-to-identify-the-origin-of-idiopathic-right-ventricular-outflow-tract-ventricular-tachycardia-during-sinus-rhythm-simultaneous-amplitude-frequency-electrogram-transformation-mapping
#8
Abigail Louise D Te, Satoshi Higa, Fa-Po Chung, Chin-Yu Lin, Men-Tzung Lo, Che-An Liu, Chen Lin, Yi-Chung Chang, Shih-Lin Chang, Li-Wei Lo, Yu-Feng Hu, Ta-Chuan Tuan, Tze-Fan Chao, Jonan Liao, Yao-Ting Chang, Chung-Hsing Lin, Yuan Hung, Shinya Yamada, Kuo-Li Pan, Yenn-Jiang Lin, Shih-Ann Chen
INTRODUCTION: The signal characteristics of intracardiac bipolar electrograms at the origin of idiopathic RVOT-VT during sinus rhythm remain unclear. OBJECTIVE: The study sought to develop a novel real-time/online technique, simultaneous amplitude frequency electrogram transformation (SAFE-T), to quantify and localize the diseased ventricular substrate in idiopathic RVOT-VT. METHODS: We retrospectively investigated the intracardiac bipolar recordings in 70 consecutive patients (26% male, mean age 42±12 years) who underwent successful radiofrequency catheter ablation of idiopathic RVOT-VT...
2017: PloS One
https://www.readbyqxmd.com/read/28251877/genomic-landscape-of-cpg-rich-elements-in-human
#9
Vladimir N Babenko, Irina V Chadaeva, Yuriy L Orlov
BACKGROUND: The studies on CpG islands (CGI) and Alu elements functions, evolution, and distribution in the genome started since the discovery in nineteen eighties (1981, 1986, correspondingly). Their highly skewed genome wide distribution implies the non-random retrotransposition pattern. Besides CGIs in gene promoters, CGIs clusters were observed in the homeobox gene regions and in the macrosatellites, but the whole picture of their distribution specifics was not grasped. Attempts to identify any causative features upon their (genome wide) distribution, such as the DNA context mediated preferred insertion sites of Alu repeats, have been made to ascribe their clusters location...
February 7, 2017: BMC Evolutionary Biology
https://www.readbyqxmd.com/read/28211459/gravitational-body-forces-focus-north-american-intraplate-earthquakes
#10
Will Levandowski, Mark Zellman, Rich Briggs
Earthquakes far from tectonic plate boundaries generally exploit ancient faults, but not all intraplate faults are equally active. The North American Great Plains exemplify such intraplate earthquake localization, with both natural and induced seismicity generally clustered in discrete zones. Here we use seismic velocity, gravity and topography to generate a 3D lithospheric density model of the region; subsequent finite-element modelling shows that seismicity focuses in regions of high-gravity-derived deviatoric stress...
February 17, 2017: Nature Communications
https://www.readbyqxmd.com/read/28165334/sensitivity-of-simulated-transcranial-ultrasound-fields-to-acoustic-medium-property-maps
#11
James Robertson, Eleanor Martin, Ben Cox, Bradley E Treeby
High intensity transcranial focused ultrasound is an FDA approved treatment for essential tremor, while low-intensity applications such as neurostimulation and opening the blood brain barrier are under active research. Simulations of transcranial ultrasound propagation are used both for focusing through the skull, and predicting intracranial fields. Maps of the skull acoustic properties are necessary for accurate simulations, and can be derived from medical images using a variety of methods. The skull maps range from segmented, homogeneous models, to fully heterogeneous models derived from medical image intensity...
April 7, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28048563/we-ab-207b-05-correlation-of-normal-lung-density-changes-with-dose-after-stereotactic-body-radiotherapy-sbrt-for-early-stage-lung-cancer
#12
Q Wu, S Devpura, K Feghali, C Liu, M Ajlouni, B Movsas, I Chetty
PURPOSE: To investigate correlation of normal lung CT density changes with dose accuracy and outcome after SBRT for patients with early stage lung cancer. METHODS: Dose distributions for patients originally planned and treated using a 1-D pencil beam-based (PB-1D) dose algorithm were retrospectively recomputed using algorithms: 3-D pencil beam (PB-3D), and model-based METHODS: AAA, Acuros XB (AXB), and Monte Carlo (MC). Prescription dose was 12 Gy × 4 fractions...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048395/we-fg-206-07-assessing-the-lung-function-of-patients-with-non-small-cell-lung-cancer-using-hyperpolarized-xenon-129-dissolved-phase-mri
#13
K Qing, J Mugler, Q Chen
PURPOSE: Hyperpolarized xenon-129 dissolved-phase MRI is the first imaging technique that allows 3-dimensional regional mapping of ventilation and gas uptake by tissue and blood the in human lung. Multiple outcome measures can be produced from this method. Existing studies in subjects with major lung diseases compared to healthy controls demonstrated high sensitivities of this method to pulmonary physiological factors including ventilation, alveolar tissue density, surface-to-volume ratio, pulmonary perfusion and gas-blood barrier thickness...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048262/su-g-iep1-07-inaccuracy-of-lesion-blood-flow-quantification-related-to-the-proton-density-reference-image-in-arterial-spin-labeling-mri-of-brain-tumors
#14
M Jen, J Johnson, P Hou, H Liu
PURPOSE: Cerebral blood flow quantification in arterial spin labeling (ASL) MRI requires an estimate of the equilibrium magnetization of blood, which is often obtained by a set of proton density (PD) reference image. Normally, a constant blood-brain partition coefficient is assumed across the brain. However, this assumption may not be valid for brain lesions. This study aimed to evaluate the impact of lesion-related PD variations on ASL quantification in patients with brain tumors. METHODS: MR images for posttreatment evaluation of 42 patients with brain tumors were retrospectively analyzed...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047789/su-g-iep2-13-toward-heavy-ion-computed-tomography-with-carbon-ions-a-monte-carlo-study
#15
D Shrestha, N Qin, Y Zhang, X Jia, J Wang
PURPOSE: In the present Monte Carlo study, we investigated the use of Carbon ions for computed tomography (CT) with a relatively low imaging dose. This will enable us to avoid any conversion of X-ray CT numbers to the relative stopping power (or relative electron density) values and the associated uncertainties in Carbon dose calculation. METHODS: In the first stage, we studied the propagation of Carbon nuclei through a water phantom using the Geant4 specially to understand their lateral displacement inside the phantom...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046474/th-ab-209-04-3d-light-sheet-luminescence-imaging-with-cherenkov-radiation
#16
P Bruza, H Lin, L Jarvis, D Gladstone, B Pogue
PURPOSE: To recover a three-dimensional density distribution of luminescent molecular probes located several centimeters deep within a highly scattering tissue. METHODS: We developed a novel sheet beam Cherenkov-excited luminescence scanned imaging (CELSI) methodology. The sample was irradiated by a horizontally oriented, vertically scanned 6 MV X-ray sheet beam (200mm × 5mm, 0.2mm vertical step) from a radiotherapy linear accelerator. The resulting Cherenkov light emission - and thus luminescent probe excitation - occurred exclusively along the irradiation plane due to a short diffusion path of secondary particles and Cherenkov photons...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28018953/high-resolution-three-dimensional-quantitative-map-of-the-macromolecular-proton-fraction-distribution-in-the-normal-rat-brain
#17
Anna V Naumova, Andrey E Akulov, Marina Yu Khodanovich, Vasily L Yarnykh
The presented dataset provides a normative high-resolution three-dimensional (3D) macromolecular proton fraction (MPF) map of the healthy rat brain in vivo and source images used for its reconstruction. The images were acquired using the protocol described elsewhere (Naumova, et al. High-resolution three-dimensional macromolecular proton fraction mapping for quantitative neuroanatomical imaging of the rodent brain in ultra-high magnetic fields. Neuroimage (2016) doi: 10.1016/j.neuroimage.2016.09.036). The map was reconstructed from three source images with different contrast weightings (proton density, T1, and magnetization transfer) using the single-point algorithm with a synthetic reference image...
February 2017: Data in Brief
https://www.readbyqxmd.com/read/28011432/challenges-in-quantitative-crystallographic-characterization-of-3d-thin-films-by-acom-tem
#18
A Kobler, C Kübel
Automated crystal orientation mapping for transmission electron microscopy (ACOM-TEM) has become an easy to use method for the investigation of crystalline materials and complements other TEM methods by adding local crystallographic information over large areas. It fills the gap between high resolution electron microscopy and electron back scatter diffraction in terms of spatial resolution. Recent investigations showed that spot diffraction ACOM-TEM is a quantitative method with respect to sample parameters like grain size, twin density, orientation density and others...
July 5, 2016: Ultramicroscopy
https://www.readbyqxmd.com/read/27881953/connectomic-analysis-of-brain-networks-novel-techniques-and-future-directions
#19
REVIEW
J Leonie Cazemier, Francisco Clascá, Paul H E Tiesinga
Brain networks, localized or brain-wide, exist only at the cellular level, i.e., between specific pre- and post-synaptic neurons, which are connected through functionally diverse synapses located at specific points of their cell membranes. "Connectomics" is the emerging subfield of neuroanatomy explicitly aimed at elucidating the wiring of brain networks with cellular resolution and a quantified accuracy. Such data are indispensable for realistic modeling of brain circuitry and function. A connectomic analysis, therefore, needs to identify and measure the soma, dendrites, axonal path, and branching patterns together with the synapses and gap junctions of the neurons involved in any given brain circuit or network...
2016: Frontiers in Neuroanatomy
https://www.readbyqxmd.com/read/27854315/3d-scene-reconstruction-using-omnidirectional-vision-and-lidar-a-hybrid-approach
#20
Michiel Vlaminck, Hiep Luong, Werner Goeman, Wilfried Philips
In this paper, we propose a novel approach to obtain accurate 3D reconstructions of large-scale environments by means of a mobile acquisition platform. The system incorporates a Velodyne LiDAR scanner, as well as a Point Grey Ladybug panoramic camera system. It was designed with genericity in mind, and hence, it does not make any assumption about the scene or about the sensor set-up. The main novelty of this work is that the proposed LiDAR mapping approach deals explicitly with the inhomogeneous density of point clouds produced by LiDAR scanners...
November 16, 2016: Sensors
keyword
keyword
113835
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"