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Dynamic contrast imaging

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https://www.readbyqxmd.com/read/27925417/effects-of-temperature-on-multiparametric-evaluation-of-hindlimb-ischemia-with-dynamic-fluorescence-imaging
#1
Wenjuan Cai, Huizhi Guang, Chuangjian Cai, Jianwen Luo
Quantitative evaluation of hindlimb ischemia is essential for early diagnosis and therapy of peripheral arterial disease (PAD). Dynamic imaging using near-infrared (NIR) fluorophore indocyanine green (ICG) is a noninvasive and effective tool to monitor multiple vascular parameters including perfusion rate (PR), perfusion vascular density (PVD) and hemodynamics. It has been previously demonstrated that temperature changes could lead to significant variations of blood flow rate and vascular perfusion. In this paper, multiparametric evaluation of hindlimb ischemia was performed at different temperatures...
December 7, 2016: Journal of Biophotonics
https://www.readbyqxmd.com/read/27922124/convex-analysis-of-mixtures-for-separating-non-negative-well-grounded-sources
#2
Yitan Zhu, Niya Wang, David J Miller, Yue Wang
Blind Source Separation (BSS) is a powerful tool for analyzing composite data patterns in many areas, such as computational biology. We introduce a novel BSS method, Convex Analysis of Mixtures (CAM), for separating non-negative well-grounded sources, which learns the mixing matrix by identifying the lateral edges of the convex data scatter plot. We propose and prove a sufficient and necessary condition for identifying the mixing matrix through edge detection in the noise-free case, which enables CAM to identify the mixing matrix not only in the exact-determined and over-determined scenarios, but also in the under-determined scenario...
December 6, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27921999/lift-calculations-based-on-accepted-wake-models-for-animal-flight-are-inconsistent-and-sensitive-to-vortex-dynamics
#3
Eric Gutierrez, Daniel B Quinn, Diana D Chin, David Lentink
There are three common methods for calculating the lift generated by a flying animal based on the measured airflow in the wake. However, these methods might not be accurate according to computational and robot-based studies of flapping wings. Here we test this hypothesis for the first time for a slowly flying Pacific parrotlet in still air using stereo particle image velocimetry recorded at 1000 Hz. The bird was trained to fly between two perches through a laser sheet wearing laser safety goggles. We found that the wingtip vortices generated during mid-downstroke advected down and broke up quickly, contradicting the frozen turbulence hypothesis typically assumed in animal flight experiments...
December 6, 2016: Bioinspiration & Biomimetics
https://www.readbyqxmd.com/read/27919861/multiparametric-mri-in-differentiating-pulmonary-artery-sarcoma-and-pulmonary-thromboembolism-a-preliminary-experience
#4
Min Liu, Chunhai Luo, Ying Wang, Xiaojuan Guo, Zhanhong Ma, Yuanhua Yang, Tianjing Zhang
PURPOSE: We aimed to define multiparametric magnetic resonance imaging (MRI) findings to differentiate between pulmonary artery sarcoma (PAS) and pulmonary thromboembolism (PTE). METHODS: Eleven patients with suspected PTE were prospectively included to undergo pulmonary MRI before surgery or biopsy. MRI protocol included an unenhanced sequence, diffusion-weighted imaging (DWI, b=800 s/mm2) and a dynamic contrast-enhanced sequence. Morphologic characteristics including distribution, filling defect, and intensity were observed on T1-, T2-, and fat-suppressed T2-weighted imaging, DWI, and contrast-enhanced MRI...
December 6, 2016: Diagnostic and Interventional Radiology: Official Journal of the Turkish Society of Radiology
https://www.readbyqxmd.com/read/27913009/quantitative-changes-in-late-gadolinium-enhancement-at-cardiac-magnetic-resonance-in-the-early-phase-of-acute-myocarditis
#5
Enrico Ammirati, Francesco Moroni, Paola Sormani, Angelica Peritore, Angela Milazzo, Giuseppina Quattrocchi, Manlio Cipriani, Fabrizio Oliva, Cristina Giannattasio, Maria Frigerio, Alberto Roghi, Paolo G Camici, Patrizia Pedrotti
BACKGROUND: The presence of late gadolinium enhancement (LGE) at cardiac magnetic resonance (CMR) has diagnostic and prognostic value in patients with acute myocarditis (AM). Aim of our study was to quantify the changes in LGE extension (LGE%) early after AM and evaluate its relations with biventricular function and morphology. METHODS: We investigated 76 consecutive patients with AM (acute onset of chest pain/heart failure/ventricular arrhythmias not explained by other causes, and raised troponin) that met CMR criteria based on myocardial oedema at T2-weighted images and LGE on post-contrast images at median time of 6days from onset of symptoms...
November 23, 2016: International Journal of Cardiology
https://www.readbyqxmd.com/read/27910868/relationship-between-nanotopographical-alignment-and-stem-cell-fate-with-live-imaging-and-shape-analysis
#6
Peter Newman, Jorge Luis Galenano-Niño, Pamela Graney, Joselito M Razal, Andrew I Minett, João Ribas, Raquel Ovalle-Robles, Maté Biro, Hala Zreiqat
The topography of a biomaterial regulates cellular interactions and determine stem cell fate. A complete understanding of how topographical properties affect cell behavior will allow the rational design of material surfaces that elicit specified biological functions once placed in the body. To this end, we fabricate substrates with aligned or randomly organized fibrous nanostructured topographies. Culturing adipose-derived stem cells (ASCs), we explore the dynamic relationship between the alignment of topography, cell shape and cell differentiation to osteogenic and myogenic lineages...
December 2, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27910824/accelerated-high-resolution-photoacoustic-tomography-via-compressed-sensing
#7
Simon Arridge, Paul Beard, Marta Betcke, Ben Cox, Nam Huynh, Felix Lucka, Olumide Ogunlade, Edward Zhang
Current 3D photoacoustic tomography (PAT) systems offer either high image quality or high frame rates but are not able to deliver high spatial and temporal resolution simultaneously, which limits their ability to image dynamic processes in living tissue (4D PAT). A particular example is the planar Fabry-Pérot (FP) photoacoustic scanner, which yields high-resolution 3D images but takes several minutes to sequentially map the incident photoacoustic field on the 2D sensor plane, point-by-point. However, as the spatio-temporal complexity of many absorbing tissue structures is rather low, the data recorded in such a conventional, regularly sampled fashion is often highly redundant...
December 21, 2016: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/27905865/transient-bone-marrow-edema-syndrome-versus-osteonecrosis-perfusion-patterns-at-dynamic-contrast-enhanced-mr-imaging-with-high-temporal-resolution-can-allow-differentiation
#8
Tobias Geith, Thomas Niethammer, Stefan Milz, Olaf Dietrich, Maximilian Reiser, Andrea Baur-Melnyk
Purpose To prospectively evaluate the perfusion patterns at quantitative dynamic contrast material-enhanced (DCE) magnetic resonance (MR) imaging of transient bone marrow edema syndrome (TBMES) and avascular osteonecrosis. Materials and Methods Institutional review board approval and written informed consent were obtained. Thirty-two patients (21 men, 11 women; mean age, 48 years; 26 hips, 10 knees) underwent conventional MR imaging and a dynamic contrast-enhanced three-dimensional spoiled gradient-echo sequence at 3 T...
December 1, 2016: Radiology
https://www.readbyqxmd.com/read/27904441/dynamic-contrast-enhanced-ultrasound-of-the-bowel-wall-with-quantitative-assessment-of-crohn-s-disease-activity-in-childhood
#9
Damjana Kljucevsek, Dubravka Vidmar, Darja Urlep, Rok Dezman
BACKGROUND: Contrast-enhanced ultrasound (CEUS) has become an established non-invasive, patient-friendly imaging technique which improves the characterization of lesions. In addition, dynamic contrast-enhanced ultrasound (DCE-US) provides valuable information concerning perfusion of examined organs. This review addresses current applications of CEUS in children, focused on DCE-US of the bowel wall in patients with Crohn disease, which enables realtime assessment of the bowel wall vascularity with semi-quantitative and quantitative assessment of disease activity and response to medical treatment...
December 1, 2016: Radiology and Oncology
https://www.readbyqxmd.com/read/27903865/imaging-mitochondrial-dynamics-in-human-skin-reveals-depth-dependent-hypoxia-and-malignant-potential-for-diagnosis
#10
Dimitra Pouli, Mihaela Balu, Carlo A Alonzo, Zhiyi Liu, Kyle P Quinn, Francisca Rius-Diaz, Ronald M Harris, Kristen M Kelly, Bruce J Tromberg, Irene Georgakoudi
Active changes in mitochondrial structure and organization facilitate cellular homeostasis. Because aberrant mitochondrial dynamics are implicated in a variety of human diseases, their assessment is potentially useful for diagnosis, therapy, and disease monitoring. Because current techniques for evaluating mitochondrial morphology are invasive or necessitate mitochondria-specific dyes, their clinical translation is limited. We report that mitochondrial dynamics can be monitored in vivo, within intact human skin by relying entirely on endogenous two-photon-excited fluorescence from the reduced metabolic coenzyme nicotinamide adenine dinucleotide (NADH)...
November 30, 2016: Science Translational Medicine
https://www.readbyqxmd.com/read/27902858/reliable-estimation-of-microvascular-flow-patterns-in-patients-with-disrupted-blood-brain-barrier-using-dynamic-susceptibility-contrast-mri
#11
Mikkel Bo Hansen, Anna Tietze, Jayashree Kalpathy-Cramer, Elizabeth R Gerstner, Tracy T Batchelor, Leif Østergaard, Kim Mouridsen
PURPOSE: To present and quantify the performance of a method to compute tissue hemodynamic parameters from dynamic susceptibility contrast (DSC) MRI data in brain tissue with possible nonintact blood-brain barrier. THEORY AND MATERIALS AND METHODS: We propose a Bayesian scheme to obtain perfusion metrics, including capillary transit-time heterogeneity (CTH), from DSC-MRI data in the presence of contrast agent extravasation. Initial performance assessment is performed through simulations...
November 30, 2016: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/27902592/dynamic-contrast-enhanced-breast-magnetic-resonance-imaging-for-the-prediction-of-early-and-late-recurrences-in-breast-cancer
#12
Eun Jung Choi, HyeMi Choi, Sin Ae Choi, Ji Hyun Youk
The aim of the study was to evaluate dynamic contrast-enhanced breast magnetic resonance imaging (DCE-MRI) features for the prediction of early and late recurrences in patients with breast cancer.Of 1030 breast cancer patients who underwent surgery at our hospital from January 2007 to July 2011, 83 recurrent breast cancer patients were enrolled in this study. We compared MRI features (background parenchymal enhancement [BPE], internal enhancement, adjacent vessel sign, whole-breast vascularity, initial enhancement pattern, kinetic curve types, and quantitative kinetic parameters) and clinico-pathologic variables (age, stage, histologic grade, nuclear grade, existence of lymphovascular invasion and extensive intraductal carcinoma component, and immunohistochemical profiles) between patients with early (≤2...
November 2016: Medicine (Baltimore)
https://www.readbyqxmd.com/read/27900674/serotonergic-hallucinogen-induced-visual-perceptual-alterations
#13
Michael Kometer, Franz X Vollenweider
Serotonergic hallucinogens, such as lysergic acid diethylamide (LSD), psilocybin, and N,N-dimethyltryptamine (DMT), are famous for their capacity to temporally and profoundly alter an individual's visual experiences. These visual alterations show consistent attributes despite large inter- and intra-individual variances. Many reports document a common perception of colors as more saturated, with increased brightness and contrast in the environment ("Visual Intensifications"). Environmental objects might be altered in size ("Visual illusions") or take on a modified and special meaning for the subject ("Altered self-reference")...
November 30, 2016: Current Topics in Behavioral Neurosciences
https://www.readbyqxmd.com/read/27900508/temperature-dependence-of-viscosity-relaxation-times-t1-t2-and-simulated-contrast-for-potential-perfusates-in-post-mortem-mr-angiography-pmmra
#14
Bridgette Webb, Thomas Widek, Bernhard Neumayer, Christine Bruguier, Sylvia Scheicher, Hanna Sprenger, Silke Grabherr, Thorsten Schwark, Rudolf Stollberger
Developments in post-mortem imaging increasingly focus on addressing recognised diagnostic weaknesses, especially with regard to suspected natural deaths. Post-mortem MR angiography (PMMRA) may offer additional diagnostic information to help address such weaknesses, specifically in the context of sudden cardiac death. Complete filling of the coronary arteries and acceptable contrast with surrounding tissue are essential for a successful approach to PMMRA. In this work, the suitability of different liquids for inclusion in a targeted PMMRA protocol was evaluated...
November 29, 2016: International Journal of Legal Medicine
https://www.readbyqxmd.com/read/27899451/real-time-spatial-and-temporal-mapping-of-the-distribution-of-c-di-gmp-during-biofilm-development
#15
Harikrishnan A S Nair, Saravanan Periasamy, Yang Liang, Staffan Kjelleberg, Scott A Rice
Bis-(3 ́-5 ́)-cyclic dimeric guanosine monophosphate (c-di-GMP) is a dynamic intracellular signaling molecule that plays a central role in the biofilm life cycle. Current methodologies for the quantification of c-di-GMP are typically based on chemical extraction, representing end-point measurements. Chemical methodologies also fail to take into consideration the physiological heterogeneity of the biofilm and thus represents an average c-di-GMP concentration across the entire biofilm. To address these problems, a ratiometric, image-based quantification method has been developed based on expression of the green fluorescence protein (GFP) under the control of the c-di-GMP responsive cdrA promoter (1)...
November 29, 2016: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/27898602/novel-high-spatiotemporal-resolution-versus-standard-of-care-dynamic-contrast-enhanced-breast-mri-comparison-of-image-quality
#16
Courtney K Morrison, Leah C Henze Bancroft, Wendy B DeMartini, James H Holmes, Kang Wang, Ryan J Bosca, Frank R Korosec, Roberta M Strigel
OBJECTIVE: Currently, dynamic contrast-enhanced (DCE) breast magnetic resonance imaging (MRI) prioritizes spatial resolution over temporal resolution given the limitations of acquisition techniques. The purpose of our intrapatient study was to assess the ability of a novel high spatial and high temporal resolution DCE breast MRI method to maintain image quality compared with the clinical standard-of-care (SOC) MRI. MATERIALS AND METHODS: Thirty patients, each demonstrating a focal area of enhancement (29 benign, 1 cancer) on their SOC MRI, consented to undergo a research DCE breast MRI on a second date...
November 28, 2016: Investigative Radiology
https://www.readbyqxmd.com/read/27896946/dynamic-laser-speckle-angiography-achieved-by-eigen-decomposition-filtering
#17
Chenxi Li, Ruikang Wang
A new approach is proposed for statistically analysis of laser speckle signals emerged from a living biological tissue based on eigen-decomposition to separate the dynamic speckle signals due to moving blood cells from the static speckle signals due to static tissue components, upon which to achieve angiography of the interrogated tissue in vivo. The proposed approach is tested by imaging mouse ear pinna in vivo, demonstrating its capability of providing detailed microvascular networks with high contrast, and high temporal and spatial resolutions...
November 29, 2016: Journal of Biophotonics
https://www.readbyqxmd.com/read/27895982/extended-focus-optical-coherence-microscopy-for-high-resolution-imaging-of-the-murine-brain
#18
Szymon Tamborski, Hong Chou Lyu, Hubert Dolezyczek, Monika Malinowska, Grzegorz Wilczynski, Daniel Szlag, Theo Lasser, Maciej Wojtkowski, Maciej Szkulmowski
We propose a new method and optical instrumentation for mouse brain imaging based on extended-focus optical coherence microscopy. This in vivo imaging technique allows the evaluation of the cytoarchitecture at cellular level and the circulation system dynamics in three dimensions. This minimally invasive and non-contact approach is performed without the application of contrasting agents. The optical design achieved a resolution of 2.2 μm over a distance of 800 μm, which was sufficient to obtain a detailed three-dimensional image of a wild-type mouse's brain down to the layer III of the cortex...
November 1, 2016: Biomedical Optics Express
https://www.readbyqxmd.com/read/27895875/takeaways-from-pre-contrast-t1-and-t2-breast-magnetic-resonance-imaging-in-women-with-recently-diagnosed-breast-cancer
#19
Seung Hee Han, Yeong Yi An, Bong Joo Kang, Sung Hun Kim, Eun Jae Lee
BACKGROUND: Dynamic contrast-enhanced magnetic resonance imaging (DCE - MRI) has been widely used in the management of breast cancer, and its diagnostic value in breast imaging has been demonstrated. There have only been a few reports regarding the usefulness of pre-contrast imaging. Knowledge about clinically significant findings of preoperative, pre-contrast T1 and T2 MR images will allow more accurate decisions regarding patient treatment and management. OBJECTIVES: The aim of this study was to evaluate the clinically significant findings of preoperative, pre-contrast T1 and T2 MR images in recently diagnosed breast cancer patients...
October 2016: Iranian Journal of Radiology: a Quarterly Journal Published By the Iranian Radiological Society
https://www.readbyqxmd.com/read/27894833/feasibility-of-using-ultrasonic-nakagami-imaging-for-monitoring-microwave-induced-thermal-lesion-in-ex%C3%A2-vivo-porcine-liver
#20
Siyuan Zhang, Yuqiang Han, Xingguang Zhu, Shaoqiang Shang, Guojing Huang, Lei Zhang, Gang Niu, Supin Wang, Xijing He, Mingxi Wan
The feasibility of using ultrasonic Nakagami imaging to evaluate thermal lesions induced by microwave ablation (MWA) in ex vivo porcine liver was explored. Dynamic changes in echo amplitudes and Nakagami parameters in the region of the MWA-induced thermal lesion, as well as the contrast-to-noise ratio (CNR) between the MWA-induced thermal lesion and the surrounding normal tissue, were calculated simultaneously during the MWA procedure. After MWA exposure, a bright hyper-echoic region appeared in ultrasonic B-mode and Nakagami parameter images as an indicator of the thermal lesion...
November 25, 2016: Ultrasound in Medicine & Biology
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