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Magnetic resonance physics

Stephen F Cauley, Kawin Setsompop, Berkin Bilgic, Himanshu Bhat, Borjan Gagoski, Lawrence L Wald
PURPOSE: Fast MRI acquisitions often rely on efficient traversal of k-space and hardware limitations, or other physical effects can cause the k-space trajectory to deviate from a theoretical path in a manner dependent on the image prescription and protocol parameters. Additional measurements or generalized calibrations are typically needed to characterize the discrepancies. We propose an autocalibrated technique to determine these discrepancies. METHODS: A joint optimization is used to estimate the trajectory simultaneously with the parallel imaging reconstruction, without the need for additional measurements...
October 21, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Gabor Nagy, Viktoria Baksa, Alexandra Kiss, Melinda Turani, Gaspar Banfalvi
The toxicity of gadolinium is reduced by chelating agents that render this heavy metal into contrast complexes used for medical magnetic resonance imaging. However, the dissociation of gadolinium chelates is known to generate Gd(3+) ions, the cellular toxicity of which has not been tested in details. The cytotoxic effects of Gd(III) ions were evaluated by monitoring the proliferation, measuring the cellular motility and following chromatin changes in various cell lines upon Gd(3+) treatment. Measurements applied long-term scanning microscopy and a perfusion platform that replaced the medium with test solutions, bypassed physical contact with the cell culture during experiments, and provided uninterrupted high time-resolution time-lapse photomicrography for an extended period of time...
October 22, 2016: Apoptosis: An International Journal on Programmed Cell Death
Jayd Lukenchuk, Laura A Sims, Jason J Shin
PURPOSE: The purpose of this study was to quantify the degree of variability in outcomes assessed after surgery for anterior shoulder instability in recent high-impact literature. METHODS: Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, an extensive review of the literature during a 5-year period from January 2011 through December 2015 was performed across 6 orthopaedic journals with high impact factors to identify all studies investigating outcomes after anterior shoulder instability...
October 18, 2016: Arthroscopy: the Journal of Arthroscopic & related Surgery
Clément Chesseboeuf
This document presents a non-rigid registration algorithm for the use of brain magnetic resonance (MR) images comparison. More precisely, we want to compare pre-operative and post-operative MR images in order to assess the deformation due to a surgical removal. The proposed algorithm has been studied in Chesseboeuf et al. ((Non-rigid registration of magnetic resonance imaging of brain. IEEE, 385-390. doi: 10.1109/IPTA.2015.7367172 , 2015), following ideas of Trouvé (An infinite dimensional group approach for physics based models in patterns recognition...
October 19, 2016: Acta Biotheoretica
Tina Gupta, Steven M Silverstein, Jessica A Bernard, Brian P Keane, Thomas V Papathomas, Andrea Pelletier-Baldelli, Derek J Dean, Raeana E Newberry, Ivanka Ristanovic, Vijay A Mittal
Patients with psychosis exhibit a reduced susceptibility to depth inversion illusions (DII) in which a physically concave surface is perceived as convex (e.g., the hollow mask illusion). Here, we examined the extent to which lessened susceptibility to DII characterized youth at ultra high risk (UHR) for psychosis. In this study, 44 UHR participants and 29 healthy controls judged the apparent convexity of face-like human masks, two of which were concave and the other convex. One of the concave masks was painted with realistic texture to enhance the illusion; the other was shown without such texture...
2016: NeuroImage: Clinical
Alicia Iglesias-Deus, Alejandro Pérez-Muñuzuri, Adela Urisarri, Adolfo Bautista-Casasnovas, Maria-Luz Couce
BACKGROUND: Umbilical cord hemangioma is very rare and may not be detected prenatally. However, it should be considered in differential diagnosis with other umbilical masses because it can cause significant morbidity. METHODS: We report the case of a newborn referred with suspected omphalitis and umbilical hernia. RESULTS: Physical examination showed an irreducible umbilical tumor, the size of olive, with dubious secretion. The initial suspected diagnosis was urachal or omphalomesenteric duct remnants...
October 2016: Medicine (Baltimore)
Samuel A Einstein, Bradley P Weegman, Meri T Firpo, Klearchos Papas, Michael Garwood
Techniques to monitor the oxygen partial pressure (pO<sub>2</sub>) within implanted tissue-engineered grafts (TEGs) are critically necessary for TEG development, but current methods are invasive and inaccurate. In this study, we investigated an accurate and noninvasive technique to monitor TEG pO<sub>2</sub> utilizing proton (<sup>1</sup>H) or fluorine (<sup>19</sup>F) magnetic resonance spectroscopy (MRS) relaxometry. The value of the spin-lattice relaxation rate constant (R<sub>1</sub>) of some biocompatible compounds is sensitive to dissolved oxygen (and temperature), while insensitive to other external factors...
October 19, 2016: Tissue Engineering. Part C, Methods
Michael S Crowell, Erik A Dedekam, Michael R Johnson, Scott C Dembowski, Richard B Westrick, Donald L Goss
BACKGROUND: While advanced diagnostic imaging is a large contributor to the growth in health care costs, direct-access to physical therapy is associated with decreased rates of diagnostic imaging. No study has systematically evaluated with evidence-based criteria the appropriateness of advanced diagnostic imaging, including magnetic resonance imaging (MRI), when ordered by physical therapists. The primary purpose of this study was to describe the appropriateness of magnetic resonance imaging (MRI) or magnetic resonance arthrogram (MRA) exams ordered by physical therapists in a direct-access sports physical therapy clinic...
October 2016: International Journal of Sports Physical Therapy
Gregory J O Beran, Joshua D Hartman, Yonaton N Heit
Molecular crystals occur widely in pharmaceuticals, foods, explosives, organic semiconductors, and many other applications. Thanks to substantial progress in electronic structure modeling of molecular crystals, attention is now shifting from basic crystal structure prediction and lattice energy modeling toward the accurate prediction of experimentally observable properties at finite temperatures and pressures. This Account discusses how fragment-based electronic structure methods can be used to model a variety of experimentally relevant molecular crystal properties...
October 18, 2016: Accounts of Chemical Research
Ewa Kober, Zofia Janas, Julia Jezierska
A series of oxidovanadium(V) complexes [VO(L-κ(4)O,N,N,O)(OR)] (1a, R = Et, L = L(1); 1b, R = Me, L = L(1); 2, R = Me, L = L(2); 3, R = Me, L = L(3)) were synthesized by the σ-bond metathesis reaction between [VO(OR)3] and the linear diaminebis(phenol) derivatives H2L (salans) containing different para-substituents on the phenoxo group [CMe3CH2CMe2, L(1); Me, L(2); Cl, L(3)]. As shown by X-ray crystallography complexes 1a, 1b, and 2 exhibit cis-α geometry, do have a stereogenic vanadium center, and exist as a racemic mixture of the Δ cis-α and Λ cis-α enantiomers...
October 18, 2016: Inorganic Chemistry
Zhen Zeng, Tijiang Zhang, Yihua Zhou, Xiaoxi Chen
Meningiomas are the most common primary nonneuroglial extra-axial neoplasms, which commonly present as spherical or oval masses with a dural attachment. Meningiomas without dural attachment are rare and, according to their locations, are classified into 5 varieties, including intraventricular, deep Sylvain fissure, pineal region, intraparenchymal, or subcortical meningiomas. To the best of our knowledge, intraparenchymal meningioma with cerebriform pattern has never been reported. In this paper, we report a 34-year-old Chinese male patient who presented with paroxysmal headaches and progressive loss of vision for 10 months and blindness for 2 weeks...
2016: Case Reports in Radiology
Maria Baias
What is "cultural heritage"? Is it simply our legacy of physical artifacts - or is it our collective legacy as human societies - how we want to be remembered by future generations? With time, negligence, and even military conflict working to erase the past, we must ask: Can a better understanding of our shared heritage assist us in addressing cultural differences in the present day? And how can science both help us understand the historic record and work to preserve it? In this perspective article we examine an emerging scientific method, mobile nuclear magnetic resonance, that can help us examine in a non-invasive way important objects and sites of our cultural heritage...
October 17, 2016: Magnetic Resonance in Chemistry: MRC
Shanshan Wang, Jianbo Liu, Xi Peng, Pei Dong, Qiegen Liu, Dong Liang
Compressed sensing magnetic resonance imaging (CSMRI) employs image sparsity to reconstruct MR images from incoherently undersampled K-space data. Existing CSMRI approaches have exploited analysis transform, synthesis dictionary, and their variants to trigger image sparsity. Nevertheless, the accuracy, efficiency, or acceleration rate of existing CSMRI methods can still be improved due to either lack of adaptability, high complexity of the training, or insufficient sparsity promotion. To properly balance the three factors, this paper proposes a two-layer tight frame sparsifying (TRIMS) model for CSMRI by sparsifying the image with a product of a fixed tight frame and an adaptively learned tight frame...
2016: BioMed Research International
Jixing Liu, Fuhong Yu, Jian Liu, Lifeng Cui, Zhen Zhao, Yuechang Wei, Qianyao Sun
A series of meso-microporous Cu-SAPO-34 catalysts were successfully synthesized by a one-pot hydrothermal crystallization method, and these catalysts exhibited excellent NH3-SCR performance at low temperature. Their structure and physic chemical properties were characterized by means of X-ray diffraction patterns (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), N2 sorption-desorption, nuclear magnetic resonance (NMR), Inductively Coupled Plasma-Atomic Emission spectrometer (ICP-AES), X-ray absorption spectroscopy (XPS), Temperature-programmed desorption of ammonia (NH3-TPD), Ultraviolet visible diffuse reflectance spectroscopy (UV-Vis DRS) and Temperature programmed reduction (TPR)...
October 2016: Journal of Environmental Sciences (China)
Jéssica Elias Vicentini, Marina Weiler, Sara Regina Meira Almeida, Brunno Machado de Campos, Lenise Valler, Li Min Li
Depression and anxiety symptoms are common after stroke and associated to reduction in quality of life and poor physical and social outcomes. The Default Mode Network (DMN) plays an important role in the emotional processing. We investigated whether these symptoms are associated to a disruption of DMN functional connectivity in the first month after stroke. Thirty-four subacute ischemic stroke patients were submitted to: 1) behavioral assessment through Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI) and Structured Clinical Interview for DSM Disorders; 2) neuropsychological assessment using Mini Mental State Examination and Montreal Cognitive Assessment; 3) resting state functional magnetic resonance imaging acquisition using a 3 T scanner (Philips Achieva)...
October 14, 2016: Brain Imaging and Behavior
O Rapalino, E M Ratai
Magnetic resonance spectroscopy (MRS) is a magnetic resonance-based imaging modality that allows noninvasive sampling of metabolic changes in normal and abnormal brain parenchyma. MRS is particularly useful in the differentiation of developmental or non-neoplastic disorders from neoplastic processes. MRS is also useful during routine imaging follow-up after radiation treatment or during antiangiogenic treatment and for predicting outcomes and treatment response. The objective of this article is to provide a concise but thorough review of the basic physical principles, important applications of MRS in brain tumor imaging, and future directions...
November 2016: Magnetic Resonance Imaging Clinics of North America
Karin Meissner, Annemarie Schweizer-Arau, Anna Limmer, Christine Preibisch, Roxana M Popovici, Isabel Lange, Barbara de Oriol, Florian Beissner
OBJECTIVE: To evaluate whether psychotherapy with somatosensory stimulation is effective for the treatment of pain and quality of life in patients with endometriosis-related pain. METHODS: Patients with a history of endometriosis and chronic pelvic pain were randomized to either psychotherapy with somatosensory stimulation (ie, different techniques of acupuncture point stimulation) or wait-list control for 3 months, after which all patients were treated. The primary outcome was brain connectivity assessed by functional magnetic resonance imaging...
October 6, 2016: Obstetrics and Gynecology
Ernst-Wilhelm Radue, Matthias Weigel, Roland Wiest, Horst Urbach
PURPOSE OF REVIEW: In neuroradiology, highly sophisticated methods such as MRI are implemented to investigate different entities of the central nervous system and to acquire miscellaneous images where tissues display varying degrees of characteristic signal intensity or brightness. Compared to x-ray, CT, and ultrasound, MRI produces clearer images of tissues, body fluids, and fat. The basics of MRI may be unknown to neurologists; this article introduces MRI physics, techniques, and interpretation guidelines...
October 2016: Continuum: Lifelong Learning in Neurology
Pooria Sarrami, Elizabeth Armstrong, Justine M Naylor, Ian A Harris
BACKGROUND: Whiplash injuries are among the leading injuries related to car crashes and it is important to determine the prognostic factors that predict the outcome of patients with these injuries. This meta-review aims to identify factors that are associated with outcome after acute whiplash injury. MATERIALS AND METHODS: A systematic search for all systematic reviews on outcome prediction of acute whiplash injury was conducted across several electronic databases...
October 13, 2016: Journal of Orthopaedics and Traumatology: Official Journal of the Italian Society of Orthopaedics and Traumatology
Elisa Fabbri, Chee W Chia, Richard G Spencer, Kenneth W Fishbein, David A Reiter, Donnie Cameron, Ariel C Zane, Zenobia A Moore, Marta Gonzalez-Freire, Marco Zoli, Stephanie A Studenski, Rita R Kalyani, Josephine M Egan, Luigi Ferrucci
Whether individuals with insulin resistance but without criteria for diabetes exhibit reduced mitochondrial oxidative capacity is unclear; addressing this question could guide research for new therapeutics. We investigated 248 non-diabetic participants from the Baltimore Longitudinal Study of Aging (BLSA) to determine whether impaired mitochondrial capacity is associated with prediabetes, insulin resistance, duration and severity of hyperglycemia exposure. Mitochondrial capacity was assessed as post-exercise phosphocreatine recovery time constant (τPCr) by (31)P-magnetic resonance spectroscopy, with higher τPCr reflecting reduced capacity...
October 13, 2016: Diabetes
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