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Dynamic contrast imaging

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https://www.readbyqxmd.com/read/28109242/local-spin-dynamics-of-iron-oxide-magnetic-nanoparticles-dispersed-in-different-solvents-with-variable-size-and-shape-a-1-h-nmr-study
#1
M Basini, T Orlando, P Arosio, M F Casula, D Espa, S Murgia, C Sangregorio, C Innocenti, A Lascialfari
Colloidal magnetic nanoparticles (MNPs) based on a nearly monodisperse iron oxide core and capped by oleic acid have been used as model systems for investigating the superparamagnetic spin dynamics by means of magnetometry measurements and nuclear magnetic resonance ((1)H NMR) relaxometry. The key magnetic properties (saturation magnetization, coercive field, and frequency dependent "blocking" temperature) of MNPs with different core size (3.5 nm, 8.5 nm, and 17.5 nm), shape (spherical and cubic), and dispersant (hexane and water-based formulation) have been determined...
January 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28108839/sporadic-insulinomas-on-volume-perfusion-ct-dynamic-enhancement-patterns-and-timing-of-optimal-tumour-parenchyma-contrast
#2
Liang Zhu, Wen-Ming Wu, Hua-Dan Xue, Wei Liu, Xuan Wang, Hao Sun, Ping Li, Yu-Pei Zhao, Zheng-Yu Jin
OBJECTIVES: To assess enhancement patterns of sporadic insulinomas on volume perfusion CT (VPCT), and to identify timing of optimal tumour-parenchyma contrast. METHODS: Consecutive patients who underwent VPCT for clinically suspected insulinomas were retrospectively identified. Patients with insulinomas confirmed by surgery were included, and patients with familial syndromes were excluded. Two radiologists evaluated VPCT images in consensus. Tumour-parenchyma contrast at each time point was measured, and timing of optimal contrast was determined...
January 20, 2017: European Radiology
https://www.readbyqxmd.com/read/28107381/in-vivo-two-photon-imaging-of-astrocytes-in-gfap-gfp-transgenic-mice
#3
Dongjun Guo, Jia Zou, Nicholas Rensing, Michael Wong
Astrocytes play important roles in normal brain function and neurological diseases. In vivo two-photon excitation laser scanning microscopy has the potential to reveal rapid, dynamic structural changes in cells in a variety of physiological and pathological conditions. The type of in vivo imaging method has been shown to affect the plasticity of dendritic spines of neurons, but the optimal in vivo imaging methods of astrocytes have not been established. We compared open-skull and thinned-skull imaging methods for two-photon laser microscopy of live astrocytes in neocortex of GFAP-GFP transgenic mice...
2017: PloS One
https://www.readbyqxmd.com/read/28107207/dynamic-mechanical-interactions-between-neighboring-airspaces-determine-cyclic-opening-and-closure-in-injured-lung
#4
Ludovic Broche, Gaetano Perchiazzi, Liisa Porra, Angela Tannoia, Mariangela Pellegrini, Savino Derosa, Alessandra Sindaco, João Batista Borges, Loïc Degrugilliers, Anders Larsson, Göran Hedenstierna, Anthony S Wexler, Alberto Bravin, Sylvia Verbanck, Bradford J Smith, Jason H T Bates, Sam Bayat
OBJECTIVES: Positive pressure ventilation exposes the lung to mechanical stresses that can exacerbate injury. The exact mechanism of this pathologic process remains elusive. The goal of this study was to describe recruitment/derecruitment at acinar length scales over short-time frames and test the hypothesis that mechanical interdependence between neighboring lung units determines the spatial and temporal distributions of recruitment/derecruitment, using a computational model. DESIGN: Experimental animal study...
January 19, 2017: Critical Care Medicine
https://www.readbyqxmd.com/read/28107094/dynamic-volume-assessment-of-hepatocellular-carcinoma-in-rat-livers-using-a-clinical-3t-mri-and-novel-segmentation
#5
Lorenzo A Orci, Graziano Oldani, Stephanie Lacotte, Florence Slits, Iris Friedli, Wolfgang Wirth, Christian Toso, Jean-Paul Vallée, Lindsey A Crowe
PURPOSE: In vivo liver cancer research commonly uses rodent models. One of the limitations of such models is the lack of accurate and reproducible endpoints for a dynamic assessment of growing tumor nodules. The aim of this study was to validate a noninvasive, true volume segmentation method using two rat hepatocellular carcinoma (HCC) models, correlating magnetic resonance imaging (MRI) with histological volume measurement, and with blood levels of α-fetoprotein. MATERIALS AND METHODS: We used 3T clinical MRI to quantify tumor volume with follow-up over time...
January 20, 2017: Journal of Investigative Surgery: the Official Journal of the Academy of Surgical Research
https://www.readbyqxmd.com/read/28106614/study-of-intrapatient-variability-and-reproducibility-of-quantitative-tumor-perfusion-parameters-evaluated-with-dynamic-contrast-enhanced-ultrasonography
#6
Nathalie Lassau, Bénédicte Coiffier, Laura Faivre, Baya Benatsou, Sophie Bidault, Elizabeth Girard, Bernard Asselain, Stéphanie Pitre-Champagnat, Serge Koscielny
OBJECTIVES: Dynamic contrast-enhanced (DCE) ultrasonography (US) is a functional imaging technique enabling quantitative assessment of solid tumor perfusion in metastatic patients treated with antiangiogenic therapies.The objective of this prospective single-center study was to evaluate in real-life conditions (in routine clinical practice) the intrapatient variability and reproducibility of DCE-US parameters. MATERIALS AND METHODS: Each patient provided written informed consent and had 2 DCE-US examinations (preprandial and postprandial) at baseline, day 15, and 1 month after treatment initiation...
January 18, 2017: Investigative Radiology
https://www.readbyqxmd.com/read/28106194/connectivity-pattern-modifies-excited-state-relaxation-dynamics-of-fluorophore-photoswitch-molecular-dyads
#7
F Schweighöfer, J Moreno, S Bobone, S Chiantia, A Herrmann, S Hecht, J Wachtveitl
In order to modulate the emission of BODIPY fluorophores, they were connected to a diarylethene (DAE) photoswitch via phenylene-ethynylene linkers of different lengths and orientations. The latter allowed for modulation of the electronic coupling in the prepared four BODIPY-DAE dyads, which were compared also to appropriate BODIPY and DAE model compounds by steady state as well as time-resolved spectroscopies. In their open isomers, all dyads show comparable luminescence behavior indicative of an unperturbed BODIPY fluorophore...
January 20, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28104642/evaluation-of-encephaloduroarteriosynangiosis-efficacy-using-probabilistic-independent-component-analysis-applied-to-dynamic-susceptibility-contrast-perfusion-mri
#8
A N Laiwalla, F Kurth, K Leu, R Liou, J Pamplona, Y C Ooi, N Salamon, B M Ellingson, N R Gonzalez
BACKGROUND AND PURPOSE: Indirect cerebral revascularization has been successfully used for treatment in Moyamoya disease and symptomatic intracranial atherosclerosis. While angiographic neovascularization has been demonstrated after surgery, measurements of local tissue perfusion are scarce and may not reflect the reported successful clinical outcomes. We investigated probabilistic independent component analysis and conventional perfusion parameters from DSC-MR imaging to measure postsurgical changes in tissue perfusion...
January 19, 2017: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28102959/x-ray-scatter-correction-for-multi-source-interior-computed-tomography
#9
Hao Gong, Hao Yan, Xun Jia, Bin Li, Ge Wang, Guohua Cao
PURPOSE: The schemes of multi-source interior computed tomography (CT) have shown promise for ultra-fast, organ-oriented, and low-dose dynamic imaging. Besides forward scattering, x-ray cross scattering from multiple x-ray sources activated simultaneously can further degrade image quality. Here, we investigate the overall x-ray scattering artifact in a recently proposed multi-source interior CT architecture, and present two methods for scatter correction. METHODS: Compared to single-source global CT, scattering in multi-source interior CT architecture is affected by two new factors: cross scattering from simultaneously activated multiple x-ray sources and region-of-interest (ROI) oriented interior CT mode...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28102310/coordinated-cell-motility-is-regulated-by-a-combination-of-lkb1-farnesylation-and-kinase-activity
#10
S Wilkinson, Y Hou, J T Zoine, J Saltz, C Zhang, Z Chen, L A D Cooper, A I Marcus
Cell motility requires the precise coordination of cell polarization, lamellipodia formation, adhesion, and force generation. LKB1 is a multi-functional serine/threonine kinase that associates with actin at the cellular leading edge of motile cells and suppresses FAK. We sought to understand how LKB1 coordinates these multiple events by systematically dissecting LKB1 protein domain function in combination with live cell imaging and computational approaches. We show that LKB1-actin colocalization is dependent upon LKB1 farnesylation leading to RhoA-ROCK-mediated stress fiber formation, but membrane dynamics is reliant on LKB1 kinase activity...
January 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28099162/thermography-based-blood-flow-imaging-in-human-skin-of-the-hands-and-feet-a-spectral-filtering-approach
#11
A A Sagaidachnyi, A V Fomin, D A Usanov, A V Skripal
The determination of the relationship between skin blood flow and skin temperature dynamics is the main problem in thermography-based blood flow imaging. Oscillations in skin blood flow are the source of thermal waves propagating from micro-vessels toward the skin's surface, as assumed in this study. This hypothesis allows us to use equations for the attenuation and dispersion of thermal waves for converting the temperature signal into the blood flow signal, and vice versa. We developed a spectral filtering approach (SFA), which is a new technique for thermography-based blood flow imaging...
January 18, 2017: Physiological Measurement
https://www.readbyqxmd.com/read/28099108/integration-of-contrast-enhanced-us-into-a-multimodality-approach-to-imaging-of-nodules-in-a-cirrhotic-liver-how-i-do-it
#12
Patricia C Jo, Hyun-Jung Jang, Peter N Burns, Kelly W Burak, Tae Kyoung Kim, Stephanie R Wilson
Accurate characterization of cirrhotic nodules and early diagnosis of hepatocellular carcinoma (HCC) are of vital importance. Currently, computed tomography (CT) and magnetic resonance (MR) imaging are standard modalities for the investigation of new nodules found at surveillance ultrasonography (US). This article describes the successful integration of contrast material-enhanced US into a multimodality approach for diagnosis of HCC and its benefits in this population. The application of contrast-enhanced US immediately following surveillance US allows for prompt dynamic contrast-enhanced evaluation, removing the need for further imaging of benign lesions...
February 2017: Radiology
https://www.readbyqxmd.com/read/28096523/x-ray-imaging-of-spin-currents-and-magnetisation-dynamics-at-the-nanoscale
#13
Stefano Bonetti
Understanding how spins move in time and space is the aim of both fundamental and applied research in modern magnetism. Over the past three decades, research in this field has led to technological advances that have had a major impact on our society, while improving the understanding of the fundamentals of spin physics. However, important questions still remain unanswered, because it is experimentally challenging to directly observe spins and their motion with a combined high spatial and temporal resolution...
January 18, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28092414/dce-mri-of-the-prostate-using-shutter-speed-vs-tofts-model-for-tumor-characterization-and-assessment-of-aggressiveness
#14
Stefanie J Hectors, Cecilia Besa, Mathilde Wagner, Guido H Jajamovich, George K Haines, Sara Lewis, Ashutosh Tewari, Ardeshir Rastinehad, Wei Huang, Bachir Taouli
PURPOSE: To quantify Tofts model (TM) and shutter-speed model (SSM) perfusion parameters in prostate cancer (PCa) and noncancerous peripheral zone (PZ) and to compare the diagnostic performance of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to Prostate Imaging and Reporting and Data System (PI-RADS) classification for the assessment of PCa aggressiveness. MATERIALS AND METHODS: Fifty PCa patients (mean age 60 years old) who underwent MRI at 3...
January 16, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28091590/high-performance-magneto-fluorescent-nanoparticles-assembled-from-terbium-and-gadolinium-1-3-diketones
#15
Rustem Zairov, Asiya Mustafina, Nataliya Shamsutdinova, Irek Nizameev, Beatriz Moreira, Svetlana Sudakova, Sergey Podyachev, Alfia Fattakhova, Gulnara Safina, Ingemar Lundstrom, Aidar Gubaidullin, Alberto Vomiero
Polyelectrolyte-coated nanoparticles consisting of terbium and gadolinium complexes with calix[4]arene tetra-diketone ligand were first synthesized. The antenna effect of the ligand on Tb(III) green luminescence and the presence of water molecules in the coordination sphere of Gd(III) bring strong luminescent and magnetic performance to the core-shell nanoparticles. The size and the core-shell morphology of the colloids were studied using transmission electron microscopy and dynamic light scattering. The correlation between photophysical and magnetic properties of the nanoparticles and their core composition was highlighted...
January 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28090589/spiral-perfusion-imaging-with-consecutive-echoes-spice%C3%A2-for-the-simultaneous-mapping-of-dsc-and-dce-mri-parameters-in-brain-tumor-patients-theory-and-initial-feasibility
#16
Eric S Paulson, Douglas E Prah, Kathleen M Schmainda
Dynamic contrast-enhanced (DCE) and dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI) are the perfusion imaging techniques most frequently used to probe the angiogenic character of brain neoplasms. With these methods, T1- and T2/T2*-weighted imaging sequences are used to image the distribution of gadolinium (Gd)-based contrast agents. However, it is well known that Gd exhibits combined T1, T2, and T2* shortening effects in tissue, and therefore, the results of both DCE- and DSC-MRI can be confounded by these opposing effects...
December 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28089903/advances-in-mr-angiography-with-7t-mri-from-microvascular-imaging-to-functional-angiography
#17
Chan-A Park, Chang-Ki Kang, Young-Bo Kim, Zang-Hee Cho
Over the past few decades, vascular flow-dependent imaging techniques have proven to be effective for the visualization of large vessel diseases. However, these approaches are unlikely to be efficacious for small vessels because the affected small vessels cannot always be visualized directly, owing to a lack of detection sensitivity. Recently, many researchers have introduced state-of-the-art imaging techniques to visualize cerebral microvessels using ultra-high-field (UHF) magnetic resonance angiography (MRA)...
January 12, 2017: NeuroImage
https://www.readbyqxmd.com/read/28089607/estimates-of-nasal-airflow-at-the-nasal-cycle-mid-point-improve-the-correlation-between-objective-and-subjective-measures-of-nasal-patency
#18
Courtney Gaberino, John S Rhee, Guilherme J M Garcia
INTRODUCTION: The nasal cycle represents a significant challenge when comparing pre- and post-surgery objective measures of nasal airflow. METHODS: Computational fluid dynamics (CFD) simulations of nasal airflow were conducted in 12 nasal airway obstruction patients showing significant nasal cycling between pre- and post-surgery computed tomography scans. To correct for the nasal cycle, mid-cycle models were created virtually. Subjective scores of nasal patency were obtained via the Nasal Obstruction Symptom Evaluation (NOSE) and unilateral visual analog scale (VAS)...
January 9, 2017: Respiratory Physiology & Neurobiology
https://www.readbyqxmd.com/read/28088373/dynamic-contrast-enhanced-magnetic-resonance-imaging-dce-mri-for-the-prediction-of-non-union-consolidation
#19
Christian Fischer, Mareike Nissen, Gerhard Schmidmaier, Thomas Bruckner, Hans-Ulrich Kauczor, Marc-André Weber
INTRODUCTION: Non-union perfusion can be visualized with dynamic contrast-enhanced (DCE) MRI. This study evaluated DCE-MRI to predict non-union consolidation after surgery and detect factors that affect bone healing. MATERIALS AND METHODS: Between 2010 and 2015 non-union perfusion was prospectively quantified in 205 patients (mean age, 51.5 years, 129 men, 76 women) before intervention and at 6, 12, 26, 52 and more weeks follow-up. DCE-MRI results were related to the osseous consolidation, the ability to predict successful outcome was estimated by ROC analysis...
January 9, 2017: Injury
https://www.readbyqxmd.com/read/28078795/a-continuous-infusion-dynamic-mri-model-at-3-0-tesla-for-the-serial-quantitative-evaluation-of-microvascular-proliferation-in-an-animal-model-of-glioblastoma-multiforme
#20
Hunter R Underhill
PURPOSE: To develop a continuous-infusion dynamic MRI technique to characterize tumor-associated microvascular proliferation (MVP) in a rat brain model of glioblastoma multiforme. METHODS: The proposed model assumes effects due to tumor-associated MVP (eg, vascular permeability, K(trans) ; intravascular plasma fraction, vp ) cannot be individually separated and solves for a single parameter (k(vasc) ) that quantifies the T1 -weighted contrast enhancement from dynamic images acquired during continuous contrast agent (CA) infusion...
January 12, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
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