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Synthetic mri

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
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
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...
October 15, 2016: Psychoneuroendocrinology
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
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: Seventy-three patients receiving isotretinoin due to moderate or severe acne vulgaris were included...
October 20, 2016: Cutaneous and Ocular Toxicology
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
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
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
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
Ashish Phophalia, Suman K Mitra
In this paper, we have presented a two stage method, using Kernel Principal Componenet Analysis (KPCA) and Rough Set Theory (RST), for denoising volumetric MRI data. A Rough Set Theory (RST) based clustering technique has been used for voxel based processing. The method groups similar voxels (3D cubes) using class and edge information derived from noisy input. Each cluster thus formed now represented via basis vector. These vectors now projected into to kernel space and PCA is performed in the feature space...
October 13, 2016: Magnetic Resonance Imaging
Frank Preiswerk, Matthew Toews, Cheng-Chieh Cheng, Jr-Yuan George Chiou, Chang-Sheng Mei, Lena F Schaefer, W Scott Hoge, Benjamin M Schwartz, Lawrence P Panych, Bruno Madore
PURPOSE: To combine MRI, ultrasound, and computer science methodologies toward generating MRI contrast at the high frame rates of ultrasound, inside and even outside the MRI bore. METHODS: A small transducer, held onto the abdomen with an adhesive bandage, collected ultrasound signals during MRI. Based on these ultrasound signals and their correlations with MRI, a machine-learning algorithm created synthetic MR images at frame rates up to 100 per second. In one particular implementation, volunteers were taken out of the MRI bore with the ultrasound sensor still in place, and MR images were generated on the basis of ultrasound signal and learned correlations alone in a "scannerless" manner...
October 13, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Falk Mancke, Gintarė Kaklauskaitė, Jennifer Kollmer, Markus Weiler
Nitrous oxide (N2O), a long-standing anesthetic, is known for its recreational use, and its consumption is on the rise. Several case studies have reported neurological and psychiatric complications of N2O use. To date, however, there has not been a study using standardized diagnostic procedures to assess psychiatric comorbidities in a patient consuming N2O. Here, we report about a 35-year-old male with magnetic resonance imaging confirmed subacute myelopathy induced by N2O consumption, who suffered from comorbid cannabinoid and nicotine dependence as well as abuse of amphetamines, cocaine, lysergic acid diethylamide, and ketamine...
2016: Substance Abuse and Rehabilitation
Gernot Heitmann, Marcel Dommaschk, Roland Löw, Rainer Herges
The synthesis of a borylated Ni(2+) porphyrin and its application as a versatile precursor for building up functional ortho-substituted tetraaryl porphyrin architectures is reported. This precursor porphyrin provides the basis for efficient modular syntheses of porphyrin compounds with covalently attached axial ligands which are important as enzyme model complexes, electron transfer dyads, and many other applications. In the present study, the precursor porphyrin was used for the synthesis of molecular spin switches which previously showed high potential as photoresponsive contrast agents for magnetic resonance imaging...
October 7, 2016: Organic Letters
Andrew Lang, Aaron Carass, Bruno M Jedynak, Sharon D Solomon, Peter A Calabresi, Jerry L Prince
As optical coherence tomography (OCT) has increasingly become a standard modality for imaging the retina, automated algorithms for processing OCT data have become necessary to do large scale studies looking for changes in specific layers. To provide accurate results, many of these algorithms rely on the consistency of layer intensities within a scan. Unfortunately, OCT data often exhibits inhomogeneity in a given layer's intensities, both within and between images. This problem negatively affects the performance of segmentation algorithms and little prior work has been done to correct this data...
April 2016: Proceedings of the IEEE International Symposium on Biomedical Imaging: from Nano to Macro
Harrison Kim, Tao Yu, Betul Cam-Etoz, Thomas van Groen, William J Hubbard, Irshad H Chaudry
OBJECTIVE 17α-ethynylestradiol-3-sulfate (EE-3-SO4) is a highly water-soluble synthetic estrogen that has an extended half-life (∼ 10 hours) over that of naturally occurring estrogen (∼ 10 minutes). In this study, EE-3-SO4 was evaluated in a lateral fluid percussion-induced traumatic brain injury (TBI) model in rats. METHODS A total of 9 groups of Sprague-Dawley rats underwent craniectomy. Twenty-four hours later, lateral fluid percussion was applied to 6 groups of animals to induce TBI; the remaining 3 groups served as sham control groups...
September 23, 2016: Journal of Neurosurgery
Daniel Markel, Ives Levesque, Joe Larkin, Pierre Léger, Issam El Naqa
At present, there exists few openly available methods for evaluation of simultaneous segmentation and registration algorithms. These methods allow for a combination of both techniques to track the tumor in complex settings such as adaptive radiotherapy. We have produced a quality assurance platform for evaluating this specific subset of algorithms using a preserved porcine lung in such that it is multi-modality compatible: positron emission tomography (PET), computer tomography (CT) and magnetic resonance imaging (MRI)...
October 7, 2016: Physics in Medicine and Biology
Yunjie Chen, Tianming Zhan, Ji Zhang, Hongyuan Wang
We propose a novel segmentation method based on regional and nonlocal information to overcome the impact of image intensity inhomogeneities and noise in human brain magnetic resonance images. With the consideration of the spatial distribution of different tissues in brain images, our method does not need preestimation or precorrection procedures for intensity inhomogeneities and noise. A nonlocal information based Gaussian mixture model (NGMM) is proposed to reduce the effect of noise. To reduce the effect of intensity inhomogeneity, the multigrid nonlocal Gaussian mixture model (MNGMM) is proposed to segment brain MR images in each nonoverlapping multigrid generated by using a new multigrid generation method...
2016: BioMed Research International
Anna V Naumova, Andrey E Akulov, Marina Yu Khodanovich, Vasily L Yarnykh
A well-known problem in ultra-high-field MRI is generation of high-resolution three-dimensional images for detailed characterization of white and gray matter anatomical structures. T1-weighted imaging traditionally used for this purpose suffers from the loss of contrast between white and gray matter with an increase of magnetic field strength. Macromolecular proton fraction (MPF) mapping is a new method potentially capable to mitigate this problem due to strong myelin-based contrast and independence of this parameter of field strength...
September 17, 2016: NeuroImage
Jie Shi, Wen Zhang, Miao Tang, Richard J Caselli, Yalin Wang
Landmark curves were widely adopted in neuroimaging research for surface correspondence computation and quantified morphometry analysis. However, most of the landmark based morphometry studies only focused on landmark curve shape difference. Here we propose to compute a set of conformal invariant-based shape indices, which are associated with the landmark curve induced boundary lengths in the hyperbolic parameter domain. Such shape indices may be used to identify which surfaces are conformally equivalent and further quantitatively measure surface deformation...
September 6, 2016: Medical Image Analysis
Fenghe Wang, Erwin Peng, Feng Liu, Pingjing Li, Sam Fong Yau Li, Jun Min Xue
To obtain suitable T 1 contrast agents for magnetic resonance imaging (MRI) application, aqueous Gd2O3 nanoparticles (NPs) with high longitudinal relativity (r 1) are demanded. High quality Gd2O3 NPs are usually synthesized through a non-hydrolytic route which requires post-synthetic modification to render the NPs water soluble. The current challenge is to obtain aqueous Gd2O3 NPs with high colloidal stability and enhanced r 1 relaxivity. To overcome this challenge, fluorescence-tagged amphiphilic brush copolymer (AFCP) encapsulated Gd2O3 NPs were proposed as suitable T 1 contrast agents...
October 21, 2016: Nanotechnology
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