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Synthetic mri

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https://www.readbyqxmd.com/read/27908187/dosimetric-characterization-of-mri-only-treatment-planning-for-brain-tumors-in-atlas-based-pseudo-ct-images-generated-from-standard-t1-weighted-mr-images
#1
Benjamin Demol, Christine Boydev, Juha Korhonen, Nick Reynaert
PURPOSE: Magnetic resonance imaging (MRI)-only radiotherapy treatment planning requires accurate pseudo-CT (pCT) images for precise dose calculation. The current work introduced an atlas-based method combined with MR intensity information. pCT analyses and Monte Carlo dose calculations for intracranial stereotactic treatments were performed. METHODS: Twenty-two patients, representing 35 tumor targets, were scanned using a 3D T1-weighted MRI sequence according to the clinical protocol...
December 2016: Medical Physics
https://www.readbyqxmd.com/read/27892534/improving-estimation-of-fiber-orientations-in-diffusion-mri-using-inter-subject-information-sharing
#2
Geng Chen, Pei Zhang, Ke Li, Chong-Yaw Wee, Yafeng Wu, Dinggang Shen, Pew-Thian Yap
Diffusion magnetic resonance imaging is widely used to investigate diffusion patterns of water molecules in the human brain. It provides information that is useful for tracing axonal bundles and inferring brain connectivity. Diffusion axonal tracing, namely tractography, relies on local directional information provided by the orientation distribution functions (ODFs) estimated at each voxel. To accurately estimate ODFs, data of good signal-to-noise ratio and sufficient angular samples are desired. This is however not always available in practice...
November 28, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27889836/clinical-validation-of-synthetic-brain-mri-in-children-initial-experience
#3
Hollie West, James L Leach, Blaise V Jones, Marguerite Care, Rupa Radhakrishnan, Arnold C Merrow, Enrique Alvarado, Suraj D Serai
INTRODUCTION: The purpose of this study was to determine the diagnostic accuracy of synthetic MR sequences generated through post-acquisition processing of a single sequence measuring inherent R1, R2, and PD tissue properties compared with sequences acquired conventionally as part of a routine clinical pediatric brain MR exam. METHODS: Thirty-two patients underwent routine clinical brain MRI with conventional and synthetic sequences acquired (22 abnormal). Synthetic axial T1, T2, and T2 fluid attenuation inversion recovery or proton density-weighted sequences were made to match the comparable clinical sequences...
November 26, 2016: Neuroradiology
https://www.readbyqxmd.com/read/27881126/initial-evaluation-of-prospective-cardiac-triggering-using-photoplethysmography-signals-recorded-with-a-video-camera-compared-to-pulse-oximetry-and-electrocardiography-at-7t-mri
#4
Nicolai Spicher, Markus Kukuk, Stefan Maderwald, Mark E Ladd
BACKGROUND: Accurate synchronization between magnetic resonance imaging data acquisition and a subject's cardiac activity ("triggering") is essential for reducing image artifacts but conventional, contact-based methods for this task are limited by several factors, including preparation time, patient inconvenience, and susceptibility to signal degradation. The purpose of this work is to evaluate the performance of a new contact-free triggering method developed with the aim to eventually replace conventional methods in non-cardiac imaging applications...
November 24, 2016: Biomedical Engineering Online
https://www.readbyqxmd.com/read/27867354/a-symmetry-based-method-to-infer-structural-brain-networks-from-probabilistic-tractography-data
#5
Kamal Shadi, Saideh Bakhshi, David A Gutman, Helen S Mayberg, Constantine Dovrolis
Recent progress in diffusion MRI and tractography algorithms as well as the launch of the Human Connectome Project (HCP) have provided brain research with an abundance of structural connectivity data. In this work, we describe and evaluate a method that can infer the structural brain network that interconnects a given set of Regions of Interest (ROIs) from probabilistic tractography data. The proposed method, referred to as Minimum Asymmetry Network Inference Algorithm (MANIA), does not determine the connectivity between two ROIs based on an arbitrary connectivity threshold...
2016: Frontiers in Neuroinformatics
https://www.readbyqxmd.com/read/27865819/buzz-juice-neurological-sequelae-of-synthetic-cannabinoids
#6
Manisha Kak, Fadi Mikhail, Sho T Yano, Rui Guan, Rimas V Lukas
The use of synthetic cannabinoids is becoming more widespread. Familiarity with the potential toxicities associated with these agents will grow in importance. We present a case of a woman who developed onset of confusion, visual hallucinations, and ataxia after vaporizing synthetic cannabinoids. MRI imaging demonstrated restricted diffusion and increased T2/FLAIR signal in the corpus callosum and cerebellar peduncles.
November 16, 2016: Journal of Clinical Neuroscience: Official Journal of the Neurosurgical Society of Australasia
https://www.readbyqxmd.com/read/27863744/towards-the-improved-quantification-of-in-vivo-abnormal-wall-shear-stresses-in-bav-affected-patients-from-4d-flow-imaging-benchmarking-and-application-to-real-data
#7
F Piatti, S Pirola, M Bissell, I Nesteruk, F Sturla, A Della Corte, A Redaelli, E Votta
Bicuspid aortic valve (BAV), i.e. the fusion of two aortic valve cusps, is the most frequent congenital cardiac malformation. Its progression is often characterized by accelerated leaflet calcification and aortic wall dilation. These processes are likely enhanced by altered biomechanical stimuli, including fluid-dynamic wall shear stresses (WSS) acting on both the aortic wall and the aortic valve. Several studies have proposed the exploitation of 4D-flow magnetic resonance imaging sequences to characterize abnormal in vivo WSS in BAV-affected patients, to support prognosis and timing of intervention...
November 11, 2016: Journal of Biomechanics
https://www.readbyqxmd.com/read/27845653/non-stationary-rician-noise-estimation-in-parallel-mri-using-a-single-image-a-variance-stabilizing-approach
#8
Tomasz Pieciak, Santiago Aja-Fernandez, Gonzalo Vegas Sanchez-Ferrero
Parallel magnetic resonance imaging (pMRI) techniques have gained a great importance both in research and clinical communities recently since they considerably accelerate the image acquisition process. However, the image reconstruction algorithms needed to correct the subsampling artifacts affect the nature of noise, i.e. it becomes non-stationary. Some methods have been proposed in the literature dealing with the non-stationary noise in pMRI. However, their performance depends on information not usually available such as multiple acquisitions, receiver noise matrices, sensitivity coil profiles, reconstruction coefficients, or even biophysical models of the data...
November 7, 2016: IEEE Transactions on Pattern Analysis and Machine Intelligence
https://www.readbyqxmd.com/read/27818606/modeling-4d-pathological-changes-by-leveraging-normative-models
#9
Bo Wang, Marcel Prastawa, Andrei Irimia, Avishek Saha, Wei Liu, S Y Matthew Goh, Paul M Vespa, John D Van Horn, Guido Gerig
With the increasing use of efficient multimodal 3D imaging, clinicians are able to access longitudinal imaging to stage pathological diseases, to monitor the efficacy of therapeutic interventions, or to assess and quantify rehabilitation efforts. Analysis of such four-dimensional (4D) image data presenting pathologies, including disappearing and newly appearing lesions, represents a significant challenge due to the presence of complex spatio-temporal changes. Image analysis methods for such 4D image data have to include not only a concept for joint segmentation of 3D datasets to account for inherent correlations of subject-specific repeated scans but also a mechanism to account for large deformations and the destruction and formation of lesions (e...
October 2016: Computer Vision and Image Understanding: CVIU
https://www.readbyqxmd.com/read/27816633/cargo-influences-on-the-biodistribution-of-hollow-mesoporous-silica-nanoparticles-as-studied-by-quantitative-19-f-magnetic-resonance-imaging
#10
Alexander Pochert, Ina Vernikouskaya, Felix Pascher, Volker Rasche, Mika Lindén
HYPOTHESIS: Biodistribution is a key issue when it comes to medical applications of nanomaterials. Hollow mesoporous silica nanoparticles (HMSNs) loaded with fluorine compounds can be applied as positive magnetic resonance imaging (MRI) contrast agents (CAs). These CAs exhibit an unusual biodistribution which is influenced by the cargo and which could be linked to their serum protein adsorption behaviour. EXPERIMENTS: HMSNs were post-synthetically loaded with perfluoro-15-crown-5-ether (PFCE)...
October 31, 2016: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/27802021/structure-and-function-of-iron-loaded-synthetic-melanin
#11
Yiwen Li, Yijun Xie, Zhao Wang, Nanzhi Zang, Fabio Carniato, Yuran Huang, Christopher M Andolina, Lucas R Parent, Treffly B Ditri, Eric D Walter, Mauro Botta, Jeffrey D Rinehart, Nathan C Gianneschi
We describe a synthetic method for increasing and controlling the iron loading of synthetic melanin nanoparticles and use the resulting materials to perform a systematic quantitative investigation on their structure-property relationship. A comprehensive analysis by magnetometry, electron paramagnetic resonance, and nuclear magnetic relaxation dispersion reveals the complexities of their magnetic behavior and how these intraparticle magnetic interactions manifest in useful material properties such as their performance as MRI contrast agents...
November 1, 2016: ACS Nano
https://www.readbyqxmd.com/read/27775017/multifunctional-spio-dox-loaded-a54-homing-peptide-functionalized-dextran-g-plga-micelles-for-tumor-therapy-and-mr-imaging
#12
Jun-Qing Situ, Xiao-Juan Wang, Xiu-Liang Zhu, Xiao-Ling Xu, Xu-Qi Kang, Jing-Bo Hu, Chen-Ying Lu, Xiao-Ying Ying, Ri-Sheng Yu, Jian You, Yong-Zhong Du
Specific delivery of chemotherapy drugs and magnetic resonance imaging (MRI) contrast agent into tumor cells is one of the issues to highly efficient tumor targeting therapy and magnetic resonance imaging. Here, A54 peptide-functionalized poly(lactic-co-glycolic acid)-grafted dextran (A54-Dex-PLGA) was synthesized. The synthesized A54-Dex-PLGA could self-assemble to form micelles with a low critical micelle concentration of 22.51 μg. mL(-1) and diameter of about 50 nm. The synthetic A54-Dex-PLGA micelles can encapsulate doxorubicin (DOX) as a model anti-tumor drug and superparamagnetic iron oxide (SPIO) as a contrast agent for MRI...
October 24, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27774787/template-free-synthesis-of-hollow-porous-organosilica-fe3o4-hybrid-nanocapsules-towards-mri-guided-high-intensity-focused-ultrasound-therapy
#13
Ming Ma, Fei Yan, Minghua Yao, Zijun Wei, Dongliang Zhou, Heliang Yao, Hairong Zheng, Hangrong Chen, Jianlin Shi
Entirely differing from the common templating-based multistep strategy in fabricating multifunctional hollow mesoporous silica nanoparticles (HMSNs), a facile and template-free synthetic strategy has been established in constructing a unique hollow/mesoporous organosilica nanocapsule concurrently encapsulating both isopentyl acetate (PEA) liquid and superparamagnetic iron oxides inside (denoted as PEA@OSNCs). This novel material exhibits ultrasmall and uniform particle size (~82 nm), high surface area (~534 m2 g-1) and excellent colloidal stability in aqueous solution...
October 24, 2016: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/27771566/prenatal-maternal-cortisol-concentrations-predict-neurodevelopment-in-middle-childhood
#14
Elysia Poggi Davis, Kevin Head, Claudia Buss, Curt A Sandman
Glucocorticoids (cortisol in humans) are the end product of the hypothalamic-pituitary-adrenocortical (HPA) axis and are proposed as a key mechanism for programming fetal brain development. The present prospective longitudinal study evaluates the association between prenatal maternal cortisol concentrations and child neurodevelopment. Participants included a low risk sample of 91 mother-child pairs. Prenatal maternal plasma cortisol concentrations were measured at 19 and 31 gestational weeks. Brain development and cognitive functioning were assessed when children were 6-9 years of age...
January 2017: Psychoneuroendocrinology
https://www.readbyqxmd.com/read/27770478/deriving-frequency-dependent-spatial-patterns-in-meg-derived-resting-state-sensorimotor-network-a-novel-multiband-ica-technique
#15
Allison C Nugent, Bruce Luber, Frederick W Carver, Stephen E Robinson, Richard Coppola, Carlos A Zarate
Recently, independent components analysis (ICA) of resting state magnetoencephalography (MEG) recordings has revealed resting state networks (RSNs) that exhibit fluctuations of band-limited power envelopes. Most of the work in this area has concentrated on networks derived from the power envelope of beta bandpass-filtered data. Although research has demonstrated that most networks show maximal correlation in the beta band, little is known about how spatial patterns of correlations may differ across frequencies...
October 22, 2016: Human Brain Mapping
https://www.readbyqxmd.com/read/27764978/the-prevalence-of-sacroiliitis-in-patients-with-acne-vulgaris-using-isotretinoin
#16
Leyla Baykal Selçuk, Deniz Aksu Arıca, Hanife Baykal Şahin, Savas Yaylı, Sevgi Bahadır
BACKGROUND/OBJECTIVE: Acne vulgaris is a chronic inflammatory disease affecting the pilosebaceous unit in the skin. Isotretinoin is a synthetic vitamin A derivative regarded as the most effective agent in the treatment of acne. There have recently been increasing reports of adverse effects of isotretinoin on the skeletal system. Our aim in this study was to evaluate the rheumatic side-effects triggered by this drug, and particularly the prevalence of sacroiliitis. MATERIALS AND METHODS: A total of 73 patients receiving isotretinoin due to moderate or severe acne vulgaris were included...
November 16, 2016: Cutaneous and Ocular Toxicology
https://www.readbyqxmd.com/read/27759377/fighting-cancer-with-corroles
#17
Ruijie D Teo, Jae Youn Hwang, John Termini, Zeev Gross, Harry B Gray
Corroles are exceptionally promising platforms for the development of agents for simultaneous cancer-targeting imaging and therapy. Depending on the element chelated by the corrole, these theranostic agents may be tuned primarily for diagnostic or therapeutic function. Versatile synthetic methodologies allow for the preparation of amphipolar derivatives, which form stable noncovalent conjugates with targeting biomolecules. These conjugates can be engineered for imaging and targeting as well as therapeutic function within one theranostic assembly...
October 19, 2016: Chemical Reviews
https://www.readbyqxmd.com/read/27753154/synthetic-quantitative-mri-through-relaxometry-modelling
#18
Martina F Callaghan, Siawoosh Mohammadi, Nikolaus Weiskopf
Quantitative MRI (qMRI) provides standardized measures of specific physical parameters that are sensitive to the underlying tissue microstructure and are a first step towards achieving maps of biologically relevant metrics through in vivo histology using MRI. Recently proposed models have described the interdependence of qMRI parameters. Combining such models with the concept of image synthesis points towards a novel approach to synthetic qMRI, in which maps of fundamentally different physical properties are constructed through the use of biophysical models...
October 18, 2016: NMR in Biomedicine
https://www.readbyqxmd.com/read/27752669/green-synthesis-of-multimodal-off-on-activatable-mri-optical-probes
#19
J Gallo, N Vasimalai, M T Fernandez-Arguelles, M Bañobre-López
Diagnosis by MRI is frequently non-trivial due to the low sensitivity of the technique. Signal enhancing contrast agents (CAs) are used to aid in the analysis of MR images. We present here a simple protocol for the preparation of responsive CAs based on Mn nanosheets. Mn nanostructures presented here undergo a chemical and structural change in the presence of altered physiological conditions that activate their signal. This strategy allows for a reduction of background, increasing the sensitivity of the technique...
October 18, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/27748712/click-chemistry-in-the-development-of-contrast-agents-for-magnetic-resonance-imaging
#20
Sudath Hapuarachchige, Dmitri Artemov
Click chemistry provides fast, convenient, versatile, and reliable chemical reactions that take place between pairs of functional groups of small molecules that can be purified without chromatographic methods. Due to the fast kinetics and low or no elimination of byproducts, click chemistry is a promising approach that is rapidly gaining acceptance in drug discovery, radiochemistry, bioconjugation, and nanoscience applications. Increasing use of click chemistry in synthetic procedures or as a bioconjugation technique in diagnostic imaging is occurring because click reactions are fast, provide a quantitative yield, and produce a minimal amount of nontoxic byproducts...
October 2016: Topics in Magnetic Resonance Imaging: TMRI
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