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Dynamic imaging

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https://www.readbyqxmd.com/read/28648002/-application-value-of-whole-brain-3d-artery-spin-labeling-in-diagnosis-of-intracranial-tumors
#1
Q Q Zhao, Q X Yang, G X Xu, Y C Lü, D L Rong, L Liu, R Zhang
Objective: To investigate the perfusion characteristics of arterial spin labeling (ASL) in intracranial tumor and its application value in classification. Methods: The clinical, pathological and imaging data of 44 patients with gliomas confirmed by pathology were analyzed retrospectively, including 9 low grade gliomas, 15 high grade gliomas, 11 cases of meningiomas, 6 cases of neurilemmoma, 3 cases of metastatic tumors.Conventional plain scan, 3D- ASL and MRI dynamic enhanced imaging (DSC-MRI) were performed...
June 20, 2017: Zhonghua Yi Xue za Zhi [Chinese medical journal]
https://www.readbyqxmd.com/read/28647883/casper-computer-aided-segmentation-of-imperceptible-motion-a-learning-based-tracking-of-an-invisible-needle-in-ultrasound
#2
Parmida Beigi, Robert Rohling, Septimiu E Salcudean, Gary C Ng
PURPOSE: This paper presents a new micro-motion-based approach to track a needle in ultrasound images captured by a handheld transducer. METHODS: We propose a novel learning-based framework to track a handheld needle by detecting microscale variations of motion dynamics over time. The current state of the art on using motion analysis for needle detection uses absolute motion and hence work well only when the transducer is static. We have introduced and evaluated novel spatiotemporal and spectral features, obtained from the phase image, in a self-supervised tracking framework to improve the detection accuracy in the subsequent frames using incremental training...
June 24, 2017: International Journal of Computer Assisted Radiology and Surgery
https://www.readbyqxmd.com/read/28647400/intraoperative-registered-ultrasound-and-fluoroscopy-iruf-for-dose-calculation-during-prostate-brachytherapy-improved-accuracy-compared-to-standard-ultrasound-based-dosimetry
#3
Junghoon Lee, Omar Y Mian, Yi Le, Hee Joon Bae, E Clif Burdette, Theodore L DeWeese, Jerry L Prince, Daniel Y Song
BACKGROUND AND PURPOSE: Intraoperative transrectal ultrasound dosimetry during low-dose-rate prostate brachytherapy is imprecise due to sonographic distortion caused by seed echoes and needle tracks that obscure seed positions or create false signals as well as traumatic edema. Here we report the results of a pilot study comparing a combined ultrasound and fluoroscopy-based seed localization method (iRUF) to standard ultrasound-based dosimetry (USD). MATERIAL AND METHODS: Eighty patients undergoing permanent Pd-103 seed implantation for prostate cancer were prospectively enrolled...
June 21, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/28647385/hunger-and-disinhibition-but-not-cognitive-restraint-are-associated-with-central-norepinephrine-transporter-availability
#4
A Bresch, M Rullmann, J Luthardt, G A Becker, M Patt, Y-S Ding, A Hilbert, O Sabri, S Hesse
The relationship between food-intake related behaviours measured by the Three-Factor Eating Questionnaire (TFEQ) and in vivo norepinephrine transporter (NET) availability has not been explored yet. We investigated ten obese individuals (body mass index (BMI) 42.4 ± 3.7 kg/m(2)) and ten normal-weight healthy controls (HC, BMI 23.9 ± 2.5 kg/m(2)) with (S,S)-[(11)C]-O-methylreboxetine ([(11)C]MRB) positron emission tomography (PET). All participants completed the TFEQ, which measures cognitive restraint, disinhibition and hunger...
June 21, 2017: Appetite
https://www.readbyqxmd.com/read/28647011/brain-structural-signatures-of-adolescent-depressive-symptom-trajectories-a-longitudinal-magnetic-resonance-imaging-study
#5
Lianne Schmaal, Murat Yücel, Rachel Ellis, Nandita Vijayakumar, Julian G Simmons, Nicholas B Allen, Sarah Whittle
OBJECTIVE: Most evidence for structural brain abnormalities associated with adolescent depression is based on cross-sectional study designs that do not take into account the dynamic course of depressive symptoms and brain maturation across adolescence. In this study, a longitudinal design was used to investigate the association between different trajectories of depressive symptoms and longitudinal changes in brain structure throughout adolescence. METHOD: One hundred forty-nine adolescents were assessed on depressive symptoms and underwent structural magnetic resonance imaging at 12 years of age and were followed up multiple times until 19 years...
July 2017: Journal of the American Academy of Child and Adolescent Psychiatry
https://www.readbyqxmd.com/read/28646758/thermo-responsive-diblock-and-triblock-cationic-copolymers-at-the-silica-aqueous-interface-a-qcm-d-and-afm-study
#6
Saeed Zajforoushan Moghaddam, Kaizheng Zhu, Bo Nyström, Esben Thormann
The properties of synthesized diblock poly(N-isopropylacrylamide)-poly((3-acrylamidopropyl)trimethylammonium chloride) and triblock methoxy-poly(ethylene glycol)-poly(N-isopropylacrylamide)-poly((3-acrylamidopropyl)trimethylammonium chloride) cationic copolymers at the silica/aqueous interface are investigated using quartz crystal microbalance with dissipation monitoring (QCM-D) and atomic force microscopy (AFM). Moreover, dynamic light scattering is employed to assess the copolymers in terms of the hydrodynamic size and interchain aggregation...
June 15, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28646414/dynamic-meso-scale-anchorage-of-gpi-anchored-receptors-in-the-plasma-membrane-prion-protein-vs-thy1
#7
Yuri L Nemoto, Roger J Morris, Hiroko Hijikata, Taka A Tsunoyama, Akihiro C E Shibata, Rinshi S Kasai, Akihiro Kusumi, Takahiro K Fujiwara
The central mechanism for the transmission of the prion protein misfolding is the structural conversion of the normal cellular prion protein to the pathogenic misfolded prion protein, by the interaction with misfolded prion protein. This process might be enhanced due to the homo-dimerization/oligomerization of normal prion protein. However, the behaviors of normal prion protein in the plasma membrane have remained largely unknown. Here, using single fluorescent-molecule imaging, we found that both prion protein and Thy1, a control glycosylphosphatidylinositol-anchored protein, exhibited very similar intermittent transient immobilizations lasting for a few seconds within an area of 24...
June 24, 2017: Cell Biochemistry and Biophysics
https://www.readbyqxmd.com/read/28646234/electroporation-as-a-vaccine-delivery-system-and-a-natural-adjuvant-to-intradermal-administration-of-plasmid-dna-in-macaques
#8
Biliana Todorova, Lucille Adam, Slobodan Culina, Raphaël Boisgard, Frédéric Martinon, Antonio Cosma, Mart Ustav, Thierry Kortulewski, Roger Le Grand, Catherine Chapon
In vivo electroporation (EP) is used to enhance the uptake of nucleic acids and its association with DNA vaccination greatly stimulates immune responses to vaccine antigens delivered through the skin. However, the effect of EP on cutaneous cell behavior, the dynamics of immune cell recruitment and local inflammatory factors, have not been fully described. Here, we show that intradermal DNA vaccination combined with EP extends antigen expression to the epidermis and the subcutaneous skin muscle in non-human primates...
June 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28646198/spatiotemporal-dynamics-of-grassland-aboveground-biomass-on-the-qinghai-tibet-plateau-based-on-validated-modis-ndvi
#9
Shiliang Liu, Fangyan Cheng, Shikui Dong, Haidi Zhao, Xiaoyun Hou, Xue Wu
Spatiotemporal dynamics of aboveground biomass (AGB) is a fundamental problem for grassland environmental management on the Qinghai-Tibet Plateau (QTP). Moderate Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI) data can feasibly be used to estimate AGB at large scales, and their precise validation is necessary to utilize them effectively. In our study, the clip-harvest method was used at 64 plots in QTP grasslands to obtain actual AGB values, and a handheld hyperspectral spectrometer was used to calculate field-measured NDVI to validate MODIS NDVI...
June 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28646166/atp-release-during-cell-swelling-activates-a-ca-2-dependent-cl-current-by-autocrine-mechanism-in-mouse-hippocampal-microglia
#10
E Murana, F Pagani, B Basilico, M Sundukova, L Batti, S Di Angelantonio, B Cortese, A Grimaldi, A Francioso, P Heppenstall, P Bregestovski, C Limatola, D Ragozzino
Microglia cells, resident immune cells of the brain, survey brain parenchyma by dynamically extending and retracting their processes. Cl(-) channels, activated in the cellular response to stretch/swelling, take part in several functions deeply connected with microglia physiology, including cell shape changes, proliferation, differentiation and migration. However, the molecular identity and functional properties of these Cl(-) channels are largely unknown. We investigated the properties of swelling-activated currents in microglial from acute hippocampal slices of Cx3cr1 (+/GFP) mice by whole-cell patch-clamp and imaging techniques...
June 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28646144/using-fractional-intensities-of-time-resolved-fluorescence-to-sensitively-quantify-nadh-nad-with-genetically-encoded-fluorescent-biosensors
#11
Mengfang Chang, Lei Li, Hanyang Hu, Qingxun Hu, Aoxue Wang, Xiaodan Cao, Xiantong Yu, Sanjun Zhang, Yuzheng Zhao, Jinquan Chen, Yi Yang, Jianhua Xu
In this paper, we propose a novel and sensitive ratiometric analysis method that uses the fractional intensities of time-resolved fluorescence of genetically encoded fluorescent NADH/NAD(+) biosensors, Peredox, SoNar, and Frex. When the conformations of the biosensors change upon NADH/NAD(+) binding, the fractional intensities (α i τ i ) have opposite changing trends. Their ratios could be exploited to quantify NADH/NAD(+) levels with a larger dynamic range and higher resolution versus commonly used fluorescence intensity and lifetime methods...
June 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28646105/the-glycolytic-enzyme-phosphofructokinase-1-assembles-into-filaments
#12
Bradley A Webb, Anne M Dosey, Torsten Wittmann, Justin M Kollman, Diane L Barber
Despite abundant knowledge of the regulation and biochemistry of glycolytic enzymes, we have limited understanding on how they are spatially organized in the cell. Emerging evidence indicates that nonglycolytic metabolic enzymes regulating diverse pathways can assemble into polymers. We now show tetramer- and substrate-dependent filament assembly by phosphofructokinase-1 (PFK1), which is considered the "gatekeeper" of glycolysis because it catalyzes the step committing glucose to breakdown. Recombinant liver PFK1 (PFKL) isoform, but not platelet PFK1 (PFKP) or muscle PFK1 (PFKM) isoforms, assembles into filaments...
June 23, 2017: Journal of Cell Biology
https://www.readbyqxmd.com/read/28645844/modelling-and-interpreting-mesoscale-network-dynamics
#13
REVIEW
Ankit N Khambhati, Ann E Sizemore, Richard F Betzel, Danielle S Bassett
Recent advances in brain imaging techniques, measurement approaches, and storage capacities have provided an unprecedented supply of high temporal resolution neural data. These data present a remarkable opportunity to gain a mechanistic understanding not just of circuit structure, but also of circuit dynamics, and its role in cognition and disease. Such understanding necessitates a description of the raw observations, and a delineation of computational models and mathematical theories that accurately capture fundamental principles behind the observations...
June 20, 2017: NeuroImage
https://www.readbyqxmd.com/read/28645841/how-do-self-interest-and-other-need-interact-in-the-brain-to-determine-altruistic-behavior
#14
Jie Hu, Yue Li, Yunlu Yin, Philip R Blue, Hongbo Yu, Xiaolin Zhou
Altruistic behavior, i.e., promoting the welfare of others at a cost to oneself, is subserved by the integration of various social, affective, and economic factors represented in extensive brain regions. However, it is unclear how different regions interact to process/integrate information regarding the helper's interest and recipient's need when deciding whether to behave altruistically. Here we combined an interactive game with functional Magnetic Resonance Imaging (fMRI) and transcranial direct current stimulation (tDCS) to characterize the neural network underlying the processing/integration of self-interest and other-need...
June 20, 2017: NeuroImage
https://www.readbyqxmd.com/read/28644800/online-combination-of-epid-cherenkov-imaging-for-3d-dosimetry-in-a-liquid-phantom
#15
Petr Bruza, Jacqueline M Andreozzi, David J Gladstone, Lesley A Jarvis, Joerg Rottmann, Brian W Pogue
Online acquisition of Cherenkov and portal imaging data was combined with a reconstruction scheme called EC3D, providing a full 3D dosimetry of megavoltage X-ray beams in a water tank. The methodology was demonstrated and quantified in a single static beam. Furthermore, the dynamics and visualization of the 3D dose reconstruction were demonstrated with a volumetric modulated arc therapy (VMAT) plan for TG-119 C-Shape geometry. The developed algorithm combines depth dose information, provided by Cherenkov images, with the lateral dose distribution, provided by the electronic portal imaging device (EPID)...
June 20, 2017: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28644799/hybrid-cs-dmri-periodic-time-variant-subsampling-and-omnidirectional-total-variation-based-reconstruction
#16
Yipeng Liu, Shan Wu, Xiaolin Huang, Bing Chen, Ce Zhu
Compressive sensing (CS) has been used to accelerate dynamic magnetic resonance imaging (DMRI). Currently, the online CS-DMRI is faster, whereas the offline CS-DMRI provides higher accuracy for image reconstruction. To achieve good image reconstruction performance in terms of both speed and accuracy, we propose a hybrid CS-DMRI method using periodic timevariant subsampling for different frames. In each period, there is one reference frame that is sampled at a higher subsampling ratio. The two nearby reference frames with good reconstruction quality can be used to provide rough predictions of the other frames between them...
June 20, 2017: IEEE Transactions on Medical Imaging
https://www.readbyqxmd.com/read/28644647/quasi-low-dimensional-electron-gas-with-one-populated-band-as-a-testing-ground-for-time-dependent-density-functional-theory-of-mesoscopic-systems
#17
Vladimir U Nazarov
We find an exact analytical solution to the exchange-only time-dependent density-functional theory (TDDFT) problem for a significant class of quasi-low-dimensional (QLD) materials: QLD electron gas with only one band filled in the direction perpendicular to the layer or wire. The theory yields the TD exchange potential as an explicit nonlocal operator of the TD spin density. The dressed interband (image states) excitation spectra of quasi-two-dimensional electron gas are obtained, while the comparison with the Kohn-Sham transitions provides insights into the qualitative and quantitative role of the many-body interactions...
June 9, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28644546/-18-f-fluoromisonidazole-uptake-in-advanced-stage-non-small-cell-lung-cancer-a-voxel-by-voxel-pet-kinetics-study
#18
Daniel R McGowan, Ruth E Macpherson, Sara L Hackett, Dan Liu, Fergus V Gleeson, W Gillies McKenna, Geoff S Higgins, John D Fenwick
PURPOSE: To determine the relative abilities of compartment models to describe time-courses of 18F-fluoromisonidazole (FMISO) uptake in tumor voxels of patients with non-small cell lung cancer (NSCLC) imaged using dynamic positron emission tomography. Also to use fits of the best-performing model to investigate changes in fitted rate-constants with distance from the tumor edge. METHODS: Reversible and irreversible two- and three-tissue compartment models were fitted to 24,662 individual voxel time activity curves (TACs) obtained from tumors in 9 patients, each imaged twice...
June 23, 2017: Medical Physics
https://www.readbyqxmd.com/read/28644482/one-thousand-fold-enhancement-of-high-field-liquid-nuclear-magnetic-resonance-signals-at-room-temperature
#19
Guoquan Liu, Marcel Levien, Niels Karschin, Giacomo Parigi, Claudio Luchinat, Marina Bennati
Nuclear magnetic resonance (NMR) is a fundamental spectroscopic technique for the study of biological systems and materials, molecular imaging and the analysis of small molecules. It detects interactions at very low energies and is thus non-invasive and applicable to a variety of targets, including animals and humans. However, one of its most severe limitations is its low sensitivity, which stems from the small interaction energies involved. Here, we report that dynamic nuclear polarization in liquid solution and at room temperature can enhance the NMR signal of (13)C nuclei by up to three orders of magnitude at magnetic fields of ∼3 T...
July 2017: Nature Chemistry
https://www.readbyqxmd.com/read/28644152/incorporating-hypr-de-noising-within-iterative-pet-reconstruction-hypr-osem
#20
Ju-Chieh Kevin Cheng, Julian C Matthews, Vesna Sossi, Jose Anton-Rodriguez, Andre Salomon, Ronald Boellaard
HighlY constrained back-PRojection (HYPR) is a post-processing de-noising technique originally developed for time-resolved Magnetic Resonance Imaging. It has been recently applied to dynamic imaging for Positron Emission Tomography (PET) and shown promising results. In this work, we have developed an iterative reconstruction algorithm (HYPR-OSEM) which improves the signal-to-noise ratio (SNR) in static imaging (i.e. single frame reconstruction) by incorporating HYPR de-noising directly within the ordered subsets expectation maximization (OSEM) algorithm...
June 23, 2017: Physics in Medicine and Biology
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