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Sample records for 19f magnetic resonance

  1. Injectable hyaluronic acid hydrogel for 19F magnetic resonance imaging

    NARCIS (Netherlands)

    Yang, X.; Sun, Y.; Kootala, S.; Hilborn, J.; Heerschap, A.; Ossipov, D.

    2014-01-01

    We report on a 19F labeled injectable hyaluronic acid (HA) hydrogel that can be monitored by both 1H and 19F MR imaging. The HA based hydrogel formed via carbazone reaction can be obtained within a minute by simple mixing of HA-carbazate and HA-aldehyde derivatized polymers. 19F contrast agent was l

  2. In vivo tracking of human neural stem cells with 19F magnetic resonance imaging.

    Directory of Open Access Journals (Sweden)

    Philipp Boehm-Sturm

    Full Text Available BACKGROUND: Magnetic resonance imaging (MRI is a promising tool for monitoring stem cell-based therapy. Conventionally, cells loaded with ironoxide nanoparticles appear hypointense on MR images. However, the contrast generated by ironoxide labeled cells is neither specific due to ambiguous background nor quantitative. A strategy to overcome these drawbacks is (19F MRI of cells labeled with perfluorocarbons. We show here for the first time that human neural stem cells (NSCs, a promising candidate for clinical translation of stem cell-based therapy of the brain, can be labeled with (19F as well as detected and quantified in vitro and after brain implantation. METHODOLOGY/PRINCIPAL FINDINGS: Human NSCs were labeled with perfluoropolyether (PFPE. Labeling efficacy was assessed with (19F MR spectroscopy, influence of the label on cell phenotypes studied by immunocytochemistry. For in vitro MRI, NSCs were suspended in gelatin at varying densities. For in vivo experiments, labeled NSCs were implanted into the striatum of mice. A decrease of cell viability was observed directly after incubation with PFPE, which re-normalized after 7 days in culture of the replated cells. No label-related changes in the numbers of Ki67, nestin, GFAP, or βIII-tubulin+ cells were detected, both in vitro and on histological sections. We found that 1,000 NSCs were needed to accumulate in one image voxel to generate significant signal-to-noise ratio in vitro. A detection limit of ∼10,000 cells was found in vivo. The location and density of human cells (hunu+ on histological sections correlated well with observations in the (19F MR images. CONCLUSION/SIGNIFICANCE: Our results show that NSCs can be efficiently labeled with (19F with little effects on viability or proliferation and differentiation capacity. We show for the first time that (19F MRI can be utilized for tracking human NSCs in brain implantation studies, which ultimately aim for restoring loss of function after

  3. Probe-Specific Procedure to Estimate Sensitivity and Detection Limits for 19F Magnetic Resonance Imaging

    Science.gov (United States)

    Taylor, Alexander J.; Granwehr, Josef; Lesbats, Clémentine; Krupa, James L.; Six, Joseph S.; Pavlovskaya, Galina E.; Thomas, Neil R.; Auer, Dorothee P.; Meersmann, Thomas; Faas, Henryk M.

    2016-01-01

    Due to low fluorine background signal in vivo, 19F is a good marker to study the fate of exogenous molecules by magnetic resonance imaging (MRI) using equilibrium nuclear spin polarization schemes. Since 19F MRI applications require high sensitivity, it can be important to assess experimental feasibility during the design stage already by estimating the minimum detectable fluorine concentration. Here we propose a simple method for the calibration of MRI hardware, providing sensitivity estimates for a given scanner and coil configuration. An experimental “calibration factor” to account for variations in coil configuration and hardware set-up is specified. Once it has been determined in a calibration experiment, the sensitivity of an experiment or, alternatively, the minimum number of required spins or the minimum marker concentration can be estimated without the need for a pilot experiment. The definition of this calibration factor is derived based on standard equations for the sensitivity in magnetic resonance, yet the method is not restricted by the limited validity of these equations, since additional instrument-dependent factors are implicitly included during calibration. The method is demonstrated using MR spectroscopy and imaging experiments with different 19F samples, both paramagnetically and susceptibility broadened, to approximate a range of realistic environments. PMID:27727294

  4. Study of fluorine in silicate glass with 19F nuclear magnetic resonance spectroscopy

    Science.gov (United States)

    Duncan, T. M.; Douglass, D. C.; Csencsits, R.; Walker, K. L.

    1986-07-01

    We report an application of nuclear magnetic resonance (NMR) spectroscopy to the study of fluorine-doped silicate glass prepared by the modified chemical vapor deposition process, prior to drawing the rod into fibers. The silica contains 1.03-wt. % fluorine, as determined by the calibrated intensity of the 19F NMR spectrum. The isotropic chemical shift of the 19F spectrum shows that fluorine bonds only to silicon; there is no evidence of oxyfluorides. Analysis of the distribution of nuclear dipolar couplings between fluorine nuclei reveals that the relative populations of silicon monofluoride sites [Si(O-)3F] and species having near-neighbor fluorines, such as silicon difluoride sites [Si(O-)2F2], are nearly statistically random. That is, to a good approximation, the fluorine substitutes randomly into the oxygen sites of the silica network. There is no evidence of local clusters of fluorine sites, silicon trifluoride sites [Si(O-)F3], or silicon tetrafluoride (SiF4).

  5. Visualizing arthritic inflammation and therapeutic response by fluorine-19 magnetic resonance imaging (19F MRI

    Directory of Open Access Journals (Sweden)

    Balducci Anthony

    2012-06-01

    Full Text Available Abstract Background Non-invasive imaging of inflammation to measure the progression of autoimmune diseases, such as rheumatoid arthritis (RA, and to monitor responses to therapy is critically needed. V-Sense, a perfluorocarbon (PFC contrast agent that preferentially labels inflammatory cells, which are then recruited out of systemic circulation to sites of inflammation, enables detection by 19F MRI. With no 19F background in the host, detection is highly-specific and can act as a proxy biomarker of the degree of inflammation present. Methods Collagen-induced arthritis in rats, a model with many similarities to human RA, was used to study the ability of the PFC contrast agent to reveal the accumulation of inflammation over time using 19F MRI. Disease progression in the rat hind limbs was monitored by caliper measurements and 19F MRI on days 15, 22 and 29, including the height of clinically symptomatic disease. Naïve rats served as controls. The capacity of the PFC contrast agent and 19F MRI to assess the effectiveness of therapy was studied in a cohort of rats administered oral prednisolone on days 14 to 28. Results Quantification of 19F signal measured by MRI in affected limbs was linearly correlated with disease severity. In animals with progressive disease, increases in 19F signal reflected the ongoing recruitment of inflammatory cells to the site, while no increase in 19F signal was observed in animals receiving treatment which resulted in clinical resolution of disease. Conclusion These results indicate that 19F MRI may be used to quantitatively and qualitatively evaluate longitudinal responses to a therapeutic regimen, while additionally revealing the recruitment of monocytic cells involved in the inflammatory process to the anatomical site. This study may support the use of 19F MRI to clinically quantify and monitor the severity of inflammation, and to assess the effectiveness of treatments in RA and other diseases with an inflammatory

  6. Cell tracking using {sup 19}F magnetic resonance imaging: Technical aspects and challenges towards clinical applications

    Energy Technology Data Exchange (ETDEWEB)

    Amiri, Houshang [Radboud University Medical Center, Department of Radiology, Nijmegen (Netherlands); Radboud University Medical Center, Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Nijmegen (Netherlands); Srinivas, Mangala; Vries, I.J.M. de [Radboud University Medical Center, Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Nijmegen (Netherlands); Veltien, Andor; Uden, Mark J. van; Heerschap, Arend [Radboud University Medical Center, Department of Radiology, Nijmegen (Netherlands)

    2014-11-06

    {sup 19}F MRI is emerging as a new imaging technique for cell tracking. It is particularly attractive because of its potential for direct and precise cell quantification. The most important challenge towards in vivo applications is the sensitivity of the technique, i.e. the detection limit in a reasonable imaging time. Optimal sensitivity can be achieved with dedicated {sup 19}F compounds together with specifically adapted hardware and acquisition methods. In this paper we introduce the {sup 19}F MRI technique focusing on these key sensitivity issues and review the state-of-the-art of {sup 19}F MRI and developments towards its clinical use. We calculate {sup 19}F detection limits reported in preclinical cell and clinical {sup 19}F drug studies in terms of tissue concentration in a 1 cm{sup 3} voxel, as an alternate way to compare detection limits. We estimate that a tissue concentration of a few millimoles per litre (mM) of {sup 19}F is required for a human study at a resolution of 1 cm{sup 3}. (orig.)

  7. A General and Facile Strategy to Fabricate Multifunctional Nanoprobes for Simultaneous (19)F Magnetic Resonance Imaging, Optical/Thermal Imaging, and Photothermal Therapy.

    Science.gov (United States)

    Hu, Gaofei; Li, Nannan; Tang, Juan; Xu, Suying; Wang, Leyu

    2016-09-01

    (19)F magnetic resonance imaging (MRI), due to its high sensitivity and negligible background, is anticipated to be a powerful noninvasive, sensitive, and accurate molecular imaging technique. However, the major challenge of (19)F MRI is to increase the number of (19)F atoms while maintaining the solubility and molecular mobility of the probe. Here, we successfully developed a facile and general strategy to synthesize the multifunctional (19)F MRI nanoprobes by encapsulating the hydrophobic inorganic nanoparticles (NPs) into a hybrid polymer micelle consisting of hydrolysates of 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PDTES) and oleylamine-functionalized poly(succinimide) (PSIOAm). Due to their good water dispersibility, excellent molecular mobility resulting from the ultrathin coating, and high (19)F atom numbers, these nanoprobes generate a separate sharp singlet of (19)F nuclear magnetic resonance (NMR) signal (at -82.8 ppm) with half peak width of ∼28 Hz, which is highly applicable for (19)F MRI. Significantly, by varying the inorganic core from metals (Au), oxides (Fe3O4), fluorides (NaYF4:Yb(3+)/Er(3+)), and phosphates (YPO4) to semiconductors (Cu7S4 and Ag2S, ZnS:Mn(2+)) NPs, which renders the nanoprobes' multifunctional properties such as photothermal ability (Au, Cu7S4), magnetism (Fe3O4), fluorescence (ZnS:Mn(2+)), near-infrared (NIR) fluorescence (Ag2S), and upconversion (UC) luminescence. Meanwhile, the as-prepared nanoprobes possess relatively small sizes (about 50 nm), which is beneficial for long-time circulation. The proof-of-concept in vitro (19)F NMR and photothermal ablation of ZnS:Mn(2+)@PDTES/PSIOAm and Cu7S4@PDTES/PSIOAm nanoprobes further suggest that these nanoprobes hold wide potentials for multifunctional applications in biomedical fields. PMID:27534896

  8. Evidence for the importance of 5'-deoxy-5-fluorouridine catabolism in humans from 19F nuclear magnetic resonance spectrometry.

    Science.gov (United States)

    Malet-Martino, M C; Armand, J P; Lopez, A; Bernadou, J; Béteille, J P; Bon, M; Martino, R

    1986-04-01

    The use of a new methodology, 19F nuclear magnetic resonance, has allowed detection of all the fluorinated metabolites in the biofluids of patients treated with 5'-deoxy-5-fluorouridine (5'-dFUrd) injected i.v. at a dose of 10 g/m2 over 6 h. This technique, which requires no labeled drug, allows a direct study of the biological sample with no need for extraction or derivatization and a simultaneous identification and quantitation of all the different fluorinated metabolites. As well as the already known metabolites, unmetabolized 5'-dFUrd, 5-fluorouracil, and 5,6-dihydro-5-fluorouracil, the presence of alpha-fluoro-beta-ureidopropionic acid, alpha-fluoro-beta-alanine (FBAL), N-carboxy-alpha-fluoro-beta-alanine, and the fluoride anion F- is reported. The catabolic pathway proposed for 5'-dFUrd is analogous to that of 5-fluorouracil, completed with FBAL----F- step, and the plasmatic equilibrium of FBAL with N-carboxy-alpha-fluoro-beta-alanine, its N-carboxy derivative. The quantitative analysis of the different metabolites found in plasma and urine emphasizes the significance of the catabolic pathway. High concentrations of alpha-fluoro-beta ureidopropionic acid and FBAL are recovered in plasma from 3 h after the beginning of the perfusion to 1 h after its end. The global urinary excretion results show that there is a high excretion of 5'-dFUrd and metabolites. Unchanged 5'-dFUrd and FBAL are by far the major excretory products and are at nearly equal rates. The protocol followed in this study produces relatively low but persistent plasmatic concentrations of 5-fluorouracil throughout the perfusion. PMID:2936452

  9. Intratumoral pharmacokinetic analysis by 19F-magnetic resonance spectroscopy and cytostatic in vivo activity of gemcitabine (dFdC) in two small cell lung cancer xenografts

    DEFF Research Database (Denmark)

    Kristjansen, P E; Quistorff, B; Spang-Thomsen, M;

    1993-01-01

    small cell lung cancer (SCLC) tumor xenografts CPH SCCL 54A and 54B in nude mice. Non-invasive monitoring of the uptake and elimination of fluorine in the individual tumors was performed by in vivo 19F-magnetic resonance spectroscopy, using a 2.9 T magnet. Five dose levels in the range 5-80 mg/kg i...... therapy than 54A. This difference in sensitivity seems to be related to different delivery or uptake of the compound in the two tumor lines, since the 19F-MRS demonstrated a significantly higher antitumor accumulation of fluorine in 54B tumors compared with 54A (p < 0.05, Wilcoxons 2-sided test) following...

  10. Charge transfer in Li/CFx-silver vanadium oxide hybrid cathode batteries revealed by solid state 7Li and 19F nuclear magnetic resonance spectroscopy

    Science.gov (United States)

    Sideris, Paul J.; Yew, Rowena; Nieves, Ian; Chen, Kaimin; Jain, Gaurav; Schmidt, Craig L.; Greenbaum, Steve G.

    2014-05-01

    Solid state 7Li and 19F magic angle spinning nuclear magnetic resonance (MAS NMR) experiments are conducted on several cathodes containing CFx-Silver vanadium oxide (CFx-Ag2V4O11) hybrid cathodes discharged to 50% depth of discharge (DoD) and stored at their open-circuit voltage for a period of one and three months. Three carbonaceous sources for the CFx phase are investigated: petroleum coke-based, fibrous, and mixed fibrous. For each hybrid cathode, a measurable increase in the relative amount of lithium fluoride is observed after a three month resting period in both the 7Li and 19F NMR spectra. These changes are attributed to lithium ion migration from the silver vanadium oxide to the CFx phase during the resting period, and help clarify the mechanism behind high power handling capability of this cathode.

  11. Alternate strategies to obtain mass balance without the use of radiolabeled compounds: application of quantitative fluorine (19F) nuclear magnetic resonance (NMR) spectroscopy in metabolism studies.

    Science.gov (United States)

    Mutlib, Abdul; Espina, Robert; Atherton, James; Wang, Jianyao; Talaat, Rasmy; Scatina, JoAnn; Chandrasekaran, Appavu

    2012-03-19

    Nuclear magnetic resonance (NMR) spectroscopy is playing an increasingly important role in the quantitation of small and large molecules. Recently, we demonstrated that (1)H NMR could be used to quantitate drug metabolites isolated in submilligram quantities from biological sources. It was shown that these metabolites, once quantitated by NMR, were suitable to be used as reference standards in quantitative LC/MS-based assays, hence circumventing the need for radiolabeled material or synthetic standards to obtain plasma exposure estimates in humans and preclinical species. The quantitative capabilities of high-field NMR is further demonstrated in the current study by obtaining the mass balance of fluorinated compounds using (19)F-NMR. Two fluorinated compounds which were radio-labeled with carbon-14 on metabolically stable positions were dosed in rats and urine and feces collected. The mass balance of the compounds was obtained initially by counting the radioactivity present in each sample. Subsequently, the same sets of samples were analyzed by (19)F-NMR, and the concentrations determined by this method were compared with data obtained using radioactivity counting. It was shown that the two methods produced comparable values. To demonstrate the value of this analytical technique in drug discovery, a fluorinated compound was dosed intravenously in dogs and feces and urine collected. Initial profiling of samples showed that this compound was excreted mainly unchanged in feces, and hence, an estimate of mass balance was obtained using (19)F-NMR. The data obtained by this method was confirmed by additional quantitative studies using mass spectrometry. Hence cross-validations of the quantitative (19)F-NMR method by radioactivity counting and mass spectrometric analysis were demonstrated in this study. A strategy outlining the use of fluorinated compounds in conjunction with (19)F-NMR to understand their routes of excretion or mass balance in animals is proposed. These

  12. Theranostic Tumor Targeted Nanoparticles Combining Drug Delivery with Dual Near Infrared and (19)F Magnetic Resonance Imaging Modalities

    DEFF Research Database (Denmark)

    Vu-Quang, Hieu; Vinding, Mads Sloth; Nielsen, Thomas;

    2016-01-01

    enhanced uptake of nanoparticles via folate receptors expressed on human nasopharyngeal epidermal carcinoma (KB) cells. In vivo, higher MRI and fluorescence signals were obtained from tumors with (19)F MRI and NIR, respectively, using folate-receptor-targeted nanoparticles compared with non-targeted...

  13. Optimization of localized 19F magnetic resonance spectroscopy for the detection of fluorinated drugs in the human liver.

    NARCIS (Netherlands)

    Klomp, D.W.J.; Laarhoven, H.W.M. van; Kentgens, A.P.M.; Heerschap, A.

    2003-01-01

    Fluorine MR spectroscopy ((19)F MRS) is an indispensable tool for assessing the pharmacokinetics of fluorinated drugs. Since the metabolism of 5-fluorouracil (5FU), a frequently used cytotoxic drug, is expected to be different in normal liver and in tumor tissue, spatial localization is required for

  14. Using "On/Off" (19)F NMR/Magnetic Resonance Imaging Signals to Sense Tyrosine Kinase/Phosphatase Activity in Vitro and in Cell Lysates.

    Science.gov (United States)

    Zheng, Zhen; Sun, Hongbin; Hu, Chen; Li, Gongyu; Liu, Xiaomei; Chen, Peiyao; Cui, Yusi; Liu, Jing; Wang, Junfeng; Liang, Gaolin

    2016-03-15

    Tyrosine kinase and phosphatase are two important, antagonistic enzymes in organisms. Development of noninvasive approach for sensing their activity with high spatial and temporal resolution remains challenging. Herein, we rationally designed a hydrogelator Nap-Phe-Phe(CF3)-Glu-Tyr-Ile-OH (1a) whose supramolecular hydrogel (i.e., Gel 1a) can be subjected to tyrosine kinase-directed disassembly, and its phosphate precursor Nap-Phe-Phe(CF3)-Glu-Tyr(H2PO3)-Ile-OH (1b), which can be subjected to alkaline phosphatase (ALP)-instructed self-assembly to form supramolecular hydrogel Gel 1b, respectively. Mechanic properties and internal fibrous networks of the hydrogels were characterized with rheology and cryo transmission electron microscopy (cryo-TEM). Disassembly/self-assembly of their corresponding supramolecular hydrogels conferring respective "On/Off" (19)F NMR/MRI signals were employed to sense the activity of these two important enzymes in vitro and in cell lysates for the first time. We anticipate that our new (19)F NMR/magnetic resonance imaging (MRI) method would facilitate pharmaceutical researchers to screen new inhibitors for these two enzymes without steric hindrance. PMID:26901415

  15. Site-specific solvent exposure analysis of a membrane protein using unnatural amino acids and {sup 19}F nuclear magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Pan; Li, Dong [Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026 (China); Chen, Hongwei [High Magnetic Field Laboratory, Chinese Academy of Science, Hefei, Anhui 230031 (China); Xiong, Ying [Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026 (China); Tian, Changlin, E-mail: cltian@ustc.edu.cn [Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026 (China); High Magnetic Field Laboratory, Chinese Academy of Science, Hefei, Anhui 230031 (China)

    2011-10-22

    Highlights: {yields} Solvent isotope shift analysis of {sup 19}F-tfmF in different H{sub 2}O/D{sub 2}O molar ratio. {yields} Correlation between solvent isotope shift of {sup 19}F-spins and solvent exposure analysis. {yields} Solvent exposure analysis of membrane proteins. -- Abstract: Membrane proteins play an essential role in cellular metabolism, transportation and signal transduction across cell membranes. The scarcity of membrane protein structures has thus far prevented a full understanding of their molecular mechanisms. Preliminary topology studies and residue solvent exposure analysis have the potential to provide valuable information on membrane proteins of unknown structure. Here, a {sup 19}F-containing unnatural amino acid (trimethylfluoro-phenylalanine, tfmF) was applied to accomplish site-specific {sup 19}F spin incorporation at different sites in diacylglycerol kinase (DAGK, an Escherichia coli membrane protein) for site-specific solvent exposure analysis. Due to isotope effect on {sup 19}F spins, a standard curve for {sup 19}F-tfmF chemical shifts was drawn for varying solvent H{sub 2}O/D{sub 2}O ratios. Further site-specific {sup 19}F solvent isotope shift analysis was conducted for DAGK to distinguish residues in water-soluble loops, interfacial areas or hydrophobic membrane regions. This site-specific solvent exposure analysis method could be applied for further topological analysis of other membrane proteins.

  16. Comparative analysis of the interaction of capecitabine and gefitinib with human serum albumin using (19)F nuclear magnetic resonance-based approach.

    Science.gov (United States)

    Wu, Di; Yan, Jin; Sun, Pingchuan; Xu, Kailin; Li, Shanshan; Yang, Hongqi; Li, Hui

    2016-09-10

    Monitoring the interaction between drugs and proteins is critical to understanding drug transport and metabolism underlying pharmacodynamics. The binding capacities to human serum albumin of two anticancer drugs, capecitabine and gefitinib, were compared via an approach combining (19)F NMR, (1)H saturation transfer difference (STD) NMR, circular dichroism and docking simulations. Results showed that the two drugs interaction with human serum albumin caused (19)F NMR signal shifted to different directions. Capecitabine had accurate binding site and higher binding affinity than gefitinib. This study provided fresh insights into ligand-protein interaction and the strength of (19)F NMR approach in biomedical research was well illustrated in this case. PMID:27392172

  17. High-resolution three-dimensional 19F-magnetic resonance imaging of rat lung in situ: evaluation of airway strain in the perfluorocarbon-filled lung

    International Nuclear Information System (INIS)

    Perfluorocarbons (PFC) are biologically and chemically inert fluids with high oxygen and CO2 carrying capacities. Their use as liquid intrapulmonary gas carriers during liquid ventilation has been investigated. We established a method of high resolution 3D-19F-MRI of the totally PFC-filled lung. The goal of this study was to investigate longitudinal and circumferential airway strain in the setting of increasing airway pressures on 3D-19F-MR images of the PFC-filled lung. Sixteen female Wistar rats were euthanized and the liquid perfluorocarbon FC-84 instilled into their lungs. 3D-19F-MRI was performed at various intrapulmonary pressures. Measurements of bronchial length and cross-sectional area were obtained from transversal 2D images for each pressure range. Changes in bronchial area were used to determine circumferential strain, while longitudinal strain was calculated from changes in bronchial length. Our method of 3D-19F-MRI allowed clear visualization of the great bronchi. Longitudinal strain increased significantly up to 31.1 cmH2O. The greatest strain could be found in the range of low airway pressures. Circumferential strain increased strongly with the initial pressure rise, but showed no significant changes above 10.4 cmH2O. Longitudinal strain was generally higher in distal airways, while circumferential strain showed no difference. Analysis of mechanical characteristics showed that longitudinal and circumferential airway expansion occurred in an anisotropic fashion. Whereas longitudinal strain still increased with higher pressures, circumferential strain quickly reached a 'strain limit'. Longitudinal strain was higher in distal bronchi, as dense PFCs gravitate to dependent, in this case to dorso-basal parts of the lung, acting as liquid positive end expiratory pressure

  18. Probing the Pu4 + magnetic moment in PuF4 with 19F NMR spectroscopy

    Science.gov (United States)

    Capan, Cigdem; Dempsey, Richard J.; Sinkov, Sergey; McNamara, Bruce K.; Cho, Herman

    2016-06-01

    The magnetic fields produced by Pu4 + centers have been measured by 19F NMR spectroscopy to elucidate the Pu-F electronic interactions in polycrystalline PuF4. Spectra acquired at applied fields of 2.35 and 7.05 T reveal a linear scaling of the 19F line shape. A model is presented that treats the line broadening and shifts as due to dipolar fields produced by Pu valence electrons in localized noninteracting orbitals. Alternative explanations for the observed line shape involving covalent Pu-F bonding, superexchange interactions, and electronic configurations with enhanced magnetic moments are considered.

  19. Approaches to the assignment of {sup 19}F resonances from 3-fluorophenylalanine labeled calmodulin using solution state NMR

    Energy Technology Data Exchange (ETDEWEB)

    Kitevski-LeBlanc, Julianne L.; Evanics, Ferenc; Scott Prosser, R., E-mail: scott.prosser@utoronto.c [University of Toronto, Department of Chemistry (Canada)

    2010-06-15

    Traditional single site replacement mutations (in this case, phenylalanine to tyrosine) were compared with methods which exclusively employ {sup 15}N and {sup 19}F-edited two- and three-dimensional NMR experiments for purposes of assigning {sup 19}F NMR resonances from calmodulin (CaM), biosynthetically labeled with 3-fluorophenylalanine (3-FPhe). The global substitution of 3-FPhe for native phenylalanine was tolerated in CaM as evidenced by a comparison of {sup 1}H-{sup 15}N HSQC spectra and calcium binding assays in the presence and absence of 3-FPhe. The {sup 19}F NMR spectrum reveals six resolved resonances, one of which integrates to three 3-FPhe species, making for a total of eight fluorophenylalanines. Single phenylalanine to tyrosine mutants of five phenylalanine positions resulted in {sup 19}F NMR spectra with significant chemical shift perturbations of the remaining resonances, and provided only a single definitive assignment. Although {sup 1}H-{sup 19}F heteronucleclear NOEs proved weak, {sup 19}F-edited {sup 1}H-{sup 1}H NOESY connectivities were relatively easy to establish by making use of the {sup 3}J{sub FH} coupling between the fluorine nucleus and the adjacent fluorophenylalanine {delta} proton. {sup 19}F-edited NOESY connectivities between the {delta} protons and {alpha} and {beta} nuclei in addition to {sup 15}N-edited {sup 1}H, {sup 1}H NOESY crosspeaks proved sufficient to assign 4 of 8 {sup 19}F resonances. Controlled cleavage of the protein into two fragments using trypsin, and a repetition of the above 2D and 3D techniques resulted in unambiguous assignments of all 8 {sup 19}F NMR resonances. Our studies suggest that {sup 19}F-edited NOESY NMR spectra are generally adequate for complete assignment without the need to resort to mutational analysis.

  20. 19F nuclear magnetic resonance analysis of the carbamate reaction of alpha-fluoro-beta-alanine (FBAL), the major catabolite of fluoropyrimidines. Application to FBAL carbamate determination in body fluids of patients treated with 5'-deoxy-5-fluorouridine

    International Nuclear Information System (INIS)

    alpha-Fluoro-beta-alanine (FBAL), the major catabolite of the antineoplastic fluoropyrimidines, is an amino acid which is in equilibrium with its carbamate derivative in weakly alkaline aqueous solutions containing carbonate. In both water and control biological fluids (urine, plasma) spiked with FBAL (and sodium bicarbonate, in some cases), 19F NMR was used: (i) to determine the pH range over which FBAL carbamate is present (pH greater than or equal to 7), the maximum concentration formed occurring around pH 9, (ii) to show that the amino group of FBAL interacts very slowly with a non-protein plasma component to form a compound X, unstable in acid medium. The presumed structure of X is RCONHCH2CHFCOOH, with R different from an alkyl group but still unidentified. The behavior of FBAL in urine and plasma of rats treated with FBAL or 5'-deoxy-5-fluorouridine (5'-dFUrd), a prodrug of 5-fluorouracil, and from patients treated with 5'-dFUrd was investigated. FBAL carbamate was not present in acid medium and was therefore absent in acidic human urine. However, it was found in alkaline rat urine. FBAL carbamate was found in plasma along with the compound X. The 19F NMR spectra of FBAL and derivatives are complex since alpha-fluoro-beta-ureido-propionic acid, the precursor of FBAL in the catabolic pathway of antineoplastic fluoropyrimidines, produces a signal overlapping that of FBAL carbamate, and very close to that of compound X

  1. Magnetism, optical absorbance, and 19F NMR spectra of nafion films with self-assembling paramagnetic networks

    Energy Technology Data Exchange (ETDEWEB)

    Levin, E. M.; Chen, Q.; Bud' ko, S. L.

    2012-01-15

    Magnetization, optical absorbance, and {sup 19}F NMR spectra of Nafion transparent films as received and doped with Mn{sup 2+}, Co{sup 2+}, Fe{sup 2+}, and Fe{sup 3+} ions with and without treatment in 1H-1,2,4-triazole (trz) have been studied. Doping of Nafion with Fe{sup 2+} and Co{sup 2+} and their bridging to nitrogen of triazole yields a hybrid self-assembling paramagnetic system that exhibits interesting magnetic and optical properties. These include spin crossover phenomena between high-spin (HS) and low-spin (LS) states in Nafion-Fe{sup 2+}-trz and Nafion-Co{sup 2+}-trz accompanied by thermochromic effects in the visible range induced by temperature. A large shift of the magnetization curve induced by a magnetic field in the vicinity of the HS {leftrightarrow} LS, {approx}220 K, observed for Nafion-Fe{sup 2+}-trz has a rate of {approx}6 K/kOe, which is about three orders of magnitude larger than that in bulk spin crossover Fe{sup 2+} materials. Selective response of {sup 19}F NMR signals on doping with paramagnetic ions demonstrates that NMR can be used as spatially resolved method to study Nafion film with paramagnetic network. Both chemical shift and width of {sup 19}F NMR signals show that SO groups of Nafion, Fe or Co ions, and nitrogen of triazole are bonded whereas they form a spin crossover system. Based on a model of nanosize cylinders proposed for Nafion [K. Schmidt-Rohr and Q. Chen, Nat Mater (2008), 75], we suggest that paramagnetic ions are located inside these cylinders, forming self-assembling magnetically and optically active nanoscale networks.

  2. Recommendations concerning magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    In medicine the technique of nuclear magnetic resonance (NMR) is applied in the form of in vivo nuclear magnetic resonance spectroscopy (MRS). In vivo MRS can be carried out non-invasively. The committee of the Dutch Health Council briefly discusses the qualities and potentialities of the nuclei that will probably be used in future clinical spectroscopy: 31P, 13C, 1H (and possibly 19F and 23Na). The committee discusses several possibilities of combining imaging and spectroscopy. The imaging of nuclei other than protons is also possible with MRS. Potential applications are considered in oncology, cardiology, neurology and hepatology. (Auth.)

  3. Characterization of the ground X1 state of 204Pb19F, 206Pb19F, 207Pb19F, and 208Pb19F

    International Nuclear Information System (INIS)

    Pure rotational spectra of the ground electronic-vibrational X1 state of 204Pb19F, 206Pb19F, 207Pb19F, and 208Pb19F are measured with a resonator pulsed supersonic jet Fourier-transform microwave spectrometer. Also reported is a new measurement of the Stark effect on the optical spectra of A(leftarrow)X1 transitions. These spectra are combined with published high-resolution infrared spectra of X2↔X1 transitions in order to create a complete picture of the ground state of lead monofluoride. For the microwave data, molecules are prepared by laser ablation of lead target rods and stabilized in a supersonic jet of neon mixed with sulfur hexafluoride. For the optical Stark spectra, a continuous source of molecules is created in a nozzle heated to 1000 deg. C. The microwave spectra confirm, improve, and extend previously reported constants that describe the rotational, spin-orbit, and hyperfine interactions of the ground electronic state of the PbF molecule. A discrepancy concerning the sign of the hyperfine constant describing the 207Pb nucleus is discussed. Magnetic-field-dependent microwave spectra are used to characterize the Zeeman interaction in terms of two g factors of the body-fixed electronic wave function. The optical Stark spectra are used to characterize the electric dipole moment of the X1 and A states.

  4. (19)F MRI for quantitative in vivo cell tracking.

    NARCIS (Netherlands)

    Srinivas, M.; Heerschap, A.; Ahrens, E.T.; Figdor, C.G.; Vries, I.J.M. de

    2010-01-01

    Cellular therapy, including stem cell transplants and dendritic cell vaccines, is typically monitored for dosage optimization, accurate delivery, and localization using noninvasive imaging, of which magnetic resonance imaging (MRI) is a key modality. (19)F MRI retains the advantages of MRI as an ima

  5. 19F Spin-lattice Relaxation of Perfluoropolyethers: Dependence on Temperature and Magnetic Field Strength (7.0-14.1T)

    Science.gov (United States)

    Kadayakkara, Deepak K.; Damodaran, Krishnan; Hitchens, T. Kevin; Bulte, Jeff W.M.; Ahrens, Eric T.

    2014-01-01

    Fluorine (19F) MRI of perfluorocarbon labeled cells has become a powerful technique to track the migration and accumulation of cells in living organisms. It is common to label cells for 19F MRI with nanoemulsions of perfluoropolyethers that contain a large number of chemically equivalent fluorine atoms. Understanding the mechanisms of 19F nuclear relaxation, and in particular the spin-lattice relaxation of these molecules, is critical to improving experimental sensitivity. To date, the temperature and magnetic field strength dependence of spin-lattice relaxation rate constant (R1) for perfluoropolyethers has not been described in detail. In this study, we evaluated R1 of linear perfluoropolyether (PFPE) and cyclic perfluoro-15-crown-5 ether (PCE) at three magnetic field strengths (7.0, 9.4, and 14.1 T) and at temperatures ranging from 256-323K. Our results show that R1 of perfluoropolyethers is dominated by dipole-dipole interactions and chemical shift anisotropy. R1 increased with magnetic field strength for both PCE and PFPE. In the temperature range studied, PCE was in the fast motion regime (ωτc < 1) at all field strengths, but for PFPE, R1 passed through a maximum, from which the rotational correlation time was estimated. The importance of these measurements for the rational design of new 19F MRI agents and methods is discussed. PMID:24594752

  6. (19)F spin-lattice relaxation of perfluoropolyethers: Dependence on temperature and magnetic field strength (7.0-14.1T).

    Science.gov (United States)

    Kadayakkara, Deepak K; Damodaran, Krishnan; Hitchens, T Kevin; Bulte, Jeff W M; Ahrens, Eric T

    2014-05-01

    Fluorine ((19)F) MRI of perfluorocarbon-labeled cells has become a powerful technique to track the migration and accumulation of cells in living organisms. It is common to label cells for (19)F MRI with nanoemulsions of perfluoropolyethers that contain a large number of chemically equivalent fluorine atoms. Understanding the mechanisms of (19)F nuclear relaxation, and in particular the spin-lattice relaxation of these molecules, is critical to improving experimental sensitivity. To date, the temperature and magnetic field strength dependence of spin-lattice relaxation rate constant (R1) for perfluoropolyethers has not been described in detail. In this study, we evaluated the R1 of linear perfluoropolyether (PFPE) and cyclic perfluoro-15-crown-5 ether (PCE) at three magnetic field strengths (7.0, 9.4, and 14.1T) and at temperatures ranging from 256-323K. Our results show that R1 of perfluoropolyethers is dominated by dipole-dipole interactions and chemical shift anisotropy. R1 increased with magnetic field strength for both PCE and PFPE. In the temperature range studied, PCE was in the fast motion regime (ωτc<1) at all field strengths, but for PFPE, R1 passed through a maximum, from which the rotational correlation time was estimated. The importance of these measurements for the rational design of new (19)F MRI agents and methods is discussed. PMID:24594752

  7. (19)F-MRI for monitoring human NK cells in vivo.

    Science.gov (United States)

    Bouchlaka, Myriam N; Ludwig, Kai D; Gordon, Jeremy W; Kutz, Matthew P; Bednarz, Bryan P; Fain, Sean B; Capitini, Christian M

    2016-05-01

    The availability of clinical-grade cytokines and artificial antigen-presenting cells has accelerated interest in using natural killer (NK) cells as adoptive cellular therapy (ACT) for cancer. One of the technological shortcomings of translating therapies from animal models to clinical application is the inability to effectively and non-invasively track these cells after infusion in patients. We have optimized the nonradioactive isotope fluorine-19 ((19)F) as a means to label and track NK cells in preclinical models using magnetic resonance imaging (MRI). Human NK cells were expanded with interleukin (IL)-2 and labeled in vitro with increasing concentrations of (19)F. Doses as low as 2 mg/mL (19)F were detected by MRI. NK cell viability was only decreased at 8 mg/mL (19)F. No effects on NK cell cytotoxicity against K562 leukemia cells were observed with 2, 4 or 8 mg/mL (19)F. Higher doses of (19)F, 4 mg/mL and 8 mg/mL, led to an improved (19)F signal by MRI with 3 × 10(11) (19)F atoms per NK cell. The 4 mg/mL (19)F labeling had no effect on NK cell function via secretion of granzyme B or interferon gamma (IFNγ), compared to NK cells exposed to vehicle alone. (19)F-labeled NK cells were detectable immediately by MRI after intratumoral injection in NSG mice and up to day 8. When (19)F-labeled NK cells were injected subcutaneously, we observed a loss of signal through time at the site of injection suggesting NK cell migration to distant organs. The (19)F perfluorocarbon is a safe and effective reagent for monitoring the persistence and trafficking of NK cell infusions in vivo, and may have potential for developing novel imaging techniques to monitor ACT for cancer. PMID:27467963

  8. MRI (Magnetic Resonance Imaging)

    Science.gov (United States)

    ... Procedures Medical Imaging MRI (Magnetic Resonance Imaging) MRI (Magnetic Resonance Imaging) Share Tweet Linkedin Pin it More sharing options ... 8 MB) Also available in Other Language versions . Magnetic Resonance Imaging (MRI) is a medical imaging procedure for making ...

  9. Magnetic resonance angiography

    Science.gov (United States)

    MRA; Angiography - magnetic resonance ... Kwong RY. Cardiovascular Magnetic Resonance Imaging. In: Bonow RO, Mann DL, Zipes DP, Libby P, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine . ...

  10. Magnetic Resonance Imaging (MRI)

    Science.gov (United States)

    ... How Can I Help a Friend Who Cuts? Magnetic Resonance Imaging (MRI) KidsHealth > For Teens > Magnetic Resonance Imaging (MRI) Print A A A Text Size What's ... Exam Safety Getting Your Results What Is MRI? Magnetic resonance imaging (MRI) is a type of safe, painless testing ...

  11. The $^{15}$N($\\bm\\alpha$,$\\bm\\gamma$)$^{19}$F reaction and nucleosynthesis of $^{19}$F

    OpenAIRE

    Wilmes, S.; Wilmes, V.; Staudt, G.; Mohr, P; Hammer, J. W.

    2002-01-01

    Several resonances in the $^{15}$N($\\alpha$,$\\gamma$)$^{19}$F reaction have been investigated in the energy range between 0.6 MeV and 2.7 MeV. Resonance strengths and branching ratios have been determined. High sensitivity could be obtained by the combination of the {\\sc{dynamitron}} high current accelerator, the windowless gas target system {\\sc{rhinoceros}}, and actively shielded germanium detectors. Two levels of $^{19}$F could be observed for the first time in the ($\\alpha$,$\\gamma$) chan...

  12. 19-Fluorine nuclear magnetic resonance chemical shift variability in trifluoroacetyl species

    OpenAIRE

    Sloop, Joseph

    2013-01-01

    Joseph C SloopSchool of Science and Technology, Georgia Gwinnett College, Lawrenceville, GA, USAAbstract: This review examines the variability of chemical shifts observed in 19-fluorine (19F) nuclear magnetic resonance spectra for the trifluoroacetyl (TFA) functional group. The range of 19F chemical shifts reported spectra for the TFA group varies generally from −85 to −67 ppm relative to CFCl3. The literature revealed several factors that impact chemical shifts of the TFA...

  13. Characterization of the ground X{sub 1} state of {sup 204}Pb{sup 19}F, {sup 206}Pb{sup 19}F, {sup 207}Pb{sup 19}F, and {sup 208}Pb{sup 19}F

    Energy Technology Data Exchange (ETDEWEB)

    Mawhorter, Richard J.; Murphy, Benjamin S.; Baum, Alexander L.; Sears, Trevor J.; Yang, T.; Rupasinghe, P. M; McRaven, C. P.; Shafer-Ray, N. E.; Alphei, Lukas D.; Grabow, Jens-Uwe [Department of Physics and Astronomy, Pomona College, Claremont, California 91711-6327 (United States); Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States); Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, Oklahoma (United States); Gottfried-Wilhelm-Leibniz-Universitaet, Institut fuer Physikalische Chemie and Elektrochemie, Lehrgebiet A, D-30167 Hannover (Germany)

    2011-08-15

    Pure rotational spectra of the ground electronic-vibrational X{sub 1} state of {sup 204}Pb{sup 19}F, {sup 206}Pb{sup 19}F, {sup 207}Pb{sup 19}F, and {sup 208}Pb{sup 19}F are measured with a resonator pulsed supersonic jet Fourier-transform microwave spectrometer. Also reported is a new measurement of the Stark effect on the optical spectra of A(leftarrow)X{sub 1} transitions. These spectra are combined with published high-resolution infrared spectra of X{sub 2}{r_reversible}X{sub 1} transitions in order to create a complete picture of the ground state of lead monofluoride. For the microwave data, molecules are prepared by laser ablation of lead target rods and stabilized in a supersonic jet of neon mixed with sulfur hexafluoride. For the optical Stark spectra, a continuous source of molecules is created in a nozzle heated to 1000 deg. C. The microwave spectra confirm, improve, and extend previously reported constants that describe the rotational, spin-orbit, and hyperfine interactions of the ground electronic state of the PbF molecule. A discrepancy concerning the sign of the hyperfine constant describing the {sup 207}Pb nucleus is discussed. Magnetic-field-dependent microwave spectra are used to characterize the Zeeman interaction in terms of two g factors of the body-fixed electronic wave function. The optical Stark spectra are used to characterize the electric dipole moment of the X{sub 1} and A states.

  14. Magnetic Resonance Imaging and Magnetic Resonance Spectroscopy in Dementias

    OpenAIRE

    Hsu, Yuan-Yu; Du, An-Tao; Schuff, Norbert; Weiner, Michael W.

    2001-01-01

    This article reviews recent studies of magnetic resonance imaging and magnetic resonance spectroscopy in dementia, including Alzheimer's disease, frontotemporal dementia, dementia with Lewy bodies, idiopathic Parkinson's disease, Huntington's disease, and vascular dementia. Magnetic resonance imaging and magnetic resonance spectroscopy can detect structural alteration and biochemical abnormalities in the brain of demented subjects and may help in the differential diagnosis and early detection...

  15. Magnetic Resonance Sensors

    Directory of Open Access Journals (Sweden)

    Robert H. Morris

    2014-11-01

    Full Text Available Magnetic Resonance finds countless applications, from spectroscopy to imaging, routinely in almost all research and medical institutions across the globe. It is also becoming more frequently used for specific applications in which the whole instrument and system is designed for a dedicated application. With beginnings in borehole logging for the petro-chemical industry Magnetic Resonance sensors have been applied to fields as varied as online process monitoring for food manufacture and medical point of care diagnostics. This great diversity is seeing exciting developments in magnetic resonance sensing technology published in application specific journals where they are often not seen by the wider sensor community. It is clear that there is enormous interest in magnetic resonance sensors which represents a significant growth area. The aim of this special edition of Sensors was to address the wide distribution of relevant articles by providing a forum to disseminate cutting edge research in this field in a single open source publication.[...

  16. Efficient isotropic magnetic resonators

    OpenAIRE

    Martin, O. J. F.; Gay-Balmaz, P.

    2002-01-01

    We study experimentally and numerically a novel three-dimensional magnetic resonator structure with high isotropy. It is formed by crossed split-ring resonators and has a response independent of the illumination direction in a specific plane. The utilization of such elements to build a finite left-handed medium is discussed. (C) 2002 American Institute of Physics.

  17. Determination of {alpha}-widths in {sup 19}F relevant to fluorine nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, F. de [CSNSM, 91 - Orsay (France); Coc, A. [CSNSM, 91 - Orsay (France); Aguer, P. [CSNSM, 91 - Orsay (France); Angulo, C. [CSNSM, 91 - Orsay (France); Bogaert, G. [CSNSM, 91 - Orsay (France); Kiener, J. [CSNSM, 91 - Orsay (France); Lefebvre, A. [CSNSM, 91 - Orsay (France); Tatischeff, V. [CSNSM, 91 - Orsay (France); Thibaud, J.P. [CSNSM, 91 - Orsay (France); Fortier, S. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Maison, J.M. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Rosier, L. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Rotbard, G. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Vernotte, J. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Arnould, M. [Universite Libre de Bruxelles (Belgium). Inst. d`Astronomie et d`Astrophysique; Jorissen, A. [Universite Libre de Bruxelles (Belgium). Inst. d`Astronomie et d`Astrophysique; Mowlavi, N. [Universite Libre de Bruxelles (Belgium). Inst. d`Astronomie et d`Astrophysique

    1996-01-29

    Nucleosynthesis of fluorine in the context of helium burning occurs through the {sup 15}N({alpha},{gamma}){sup 19}F reaction. At temperatures where fluorine formation takes place in most astrophysical models, the narrow resonance associated with the 4.378 MeV level of {sup 19}F is expected to dominate the reaction rate, but its strength is not known. We used a {sup 15}N confined gas target to study this level by means of the transfer reaction {sup 15}N({sup 7}Li,t){sup 19}F at 28 MeV. Reaction products were analysed with a split pole magnetic spectrometer and the angular distributions for the first 16 levels of {sup 19}F were extracted. These distributions are fairly well reproduced by FR-DWBA calculations in the framework of an {alpha}-cluster transfer model with a compound nucleus contribution obtained by Hauser-Feshbach calculations. {alpha}-spectroscopic factors were deduced and, for unbound levels, the {alpha}-widths were determined and compared with the existing direct measurements. The {alpha}-width of the level of astrophysical interest (E{sub x} 4.378 MeV) was found to be {Gamma}{sub {alpha}}=1.5 x 10{sup -9} eV, a value 60 times smaller than the commonly used one. The astrophysical consequences for {sup 19}F production in AGB stars are discussed. (orig.).

  18. Contrast Agent in Magnetic Resonance Imaging

    DEFF Research Database (Denmark)

    Vu-Quang, Hieu

    2015-01-01

    for chemotherapy. The nanoparticles were 150 nm in size with spherical shape, which contained PFOB in the inner core and Dox and ICG in the polymeric shell. More importantly, they could target folate receptor expressing cancer cells, which provide positive in vitro and in vivo NIR and 19F MRI results. In project......Nanoparticles have been employed as contrast agent in magnetic resonance imaging (MRI) in order to improve sensitivity and accuracy in diagnosis. In addition, these contrast agents are potentially combined with other therapeutic compounds or near infrared bio-imaging (NIR) fluorophores to obtain...... theranostic or dual imaging purposes, respectively. There were two main types of MRI contrast agent that were synthesized during this PhD project including fluorine containing nanoparticles and magnetic nanoparticles. In regard of fluorine containing nanoparticles, there were two types contrast agent...

  19. Advances in magnetic resonance 10

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 10, presents a variety of contributions to the theory and practice of magnetic resonance. The book contains three chapters that examine superoperators in magnetic resonance; ultrasonically modulated paramagnetic resonance; and the utility of electron paramagnetic resonance (EPR) and electron-nuclear double-resonance (ENDOR) techniques for studying low-frequency modes of atomic fluctuations and their significance for understanding the mechanism of structural phase transitions in solids.

  20. Functional Magnetic Resonance Imaging

    Science.gov (United States)

    Voos, Avery; Pelphrey, Kevin

    2013-01-01

    Functional magnetic resonance imaging (fMRI), with its excellent spatial resolution and ability to visualize networks of neuroanatomical structures involved in complex information processing, has become the dominant technique for the study of brain function and its development. The accessibility of in-vivo pediatric brain-imaging techniques…

  1. Single spin magnetic resonance

    Science.gov (United States)

    Wrachtrup, Jörg; Finkler, Amit

    2016-08-01

    Different approaches have improved the sensitivity of either electron or nuclear magnetic resonance to the single spin level. For optical detection it has essentially become routine to observe a single electron spin or nuclear spin. Typically, the systems in use are carefully designed to allow for single spin detection and manipulation, and of those systems, diamond spin defects rank very high, being so robust that they can be addressed, read out and coherently controlled even under ambient conditions and in a versatile set of nanostructures. This renders them as a new type of sensor, which has been shown to detect single electron and nuclear spins among other quantities like force, pressure and temperature. Adapting pulse sequences from classic NMR and EPR, and combined with high resolution optical microscopy, proximity to the target sample and nanoscale size, the diamond sensors have the potential to constitute a new class of magnetic resonance detectors with single spin sensitivity. As diamond sensors can be operated under ambient conditions, they offer potential application across a multitude of disciplines. Here we review the different existing techniques for magnetic resonance, with a focus on diamond defect spin sensors, showing their potential as versatile sensors for ultra-sensitive magnetic resonance with nanoscale spatial resolution.

  2. In vivo imaging of stepwise vessel occlusion in cerebral photothrombosis of mice by 19F MRI.

    Directory of Open Access Journals (Sweden)

    Gesa Weise

    Full Text Available BACKGROUND: (19F magnetic resonance imaging (MRI was recently introduced as a promising technique for in vivo cell tracking. In the present study we compared (19F MRI with iron-enhanced MRI in mice with photothrombosis (PT at 7 Tesla. PT represents a model of focal cerebral ischemia exhibiting acute vessel occlusion and delayed neuroinflammation. METHODS/PRINCIPAL FINDINGS: Perfluorocarbons (PFC or superparamagnetic iron oxide particles (SPIO were injected intravenously at different time points after photothrombotic infarction. While administration of PFC directly after PT induction led to a strong (19F signal throughout the entire lesion, two hours delayed application resulted in a rim-like (19F signal at the outer edge of the lesion. These findings closely resembled the distribution of signal loss on T2-weighted MRI seen after SPIO injection reflecting intravascular accumulation of iron particles trapped in vessel thrombi as confirmed histologically. By sequential administration of two chemically shifted PFC compounds 0 and 2 hours after illumination the different spatial distribution of the (19F markers (infarct core/rim could be visualized in the same animal. When PFC were applied at day 6 the fluorine marker was only detected after long acquisition times ex vivo. SPIO-enhanced MRI showed slight signal loss in vivo which was much more prominent ex vivo indicative for neuroinflammation at this late lesion stage. CONCLUSION: Our study shows that vessel occlusion can be followed in vivo by (19F and SPIO-enhanced high-field MRI while in vivo imaging of neuroinflammation remains challenging. The timing of contrast agent application was the major determinant of the underlying processes depicted by both imaging techniques. Importantly, sequential application of different PFC compounds allowed depiction of ongoing vessel occlusion from the core to the margin of the ischemic lesions in a single MRI measurement.

  3. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) ... conditions such as: brain tumors stroke infections developmental anomalies hydrocephalus — dilatation of fluid spaces within the brain ( ...

  4. Magnetic Resonance Imaging (MRI) Safety

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) Safety What is MRI and how does ... What is MRI and how does it work? Magnetic resonance imaging, or MRI, is a way of obtaining very ...

  5. Resonant magnetic vortices

    International Nuclear Information System (INIS)

    By using the complex angular momentum method, we provide a semiclassical analysis of electron scattering by a magnetic vortex of Aharonov-Bohm type. Regge poles of the S matrix are associated with surface waves orbiting around the vortex and supported by a magnetic field discontinuity. Rapid variations of sharp characteristic shapes can be observed on scattering cross sections. They correspond to quasibound states which are Breit-Wigner-type resonances associated with surface waves and which can be considered as quantum analogues of acoustic whispering-gallery modes. Such a resonant magnetic vortex could provide a different kind of artificial atom while the semiclassical approach developed here could be profitably extended in various areas of the physics of vortices

  6. Magnetic resonance of phase transitions

    CERN Document Server

    Owens, Frank J; Farach, Horacio A

    1979-01-01

    Magnetic Resonance of Phase Transitions shows how the effects of phase transitions are manifested in the magnetic resonance data. The book discusses the basic concepts of structural phase and magnetic resonance; various types of magnetic resonances and their underlying principles; and the radiofrequency methods of nuclear magnetic resonance. The text also describes quadrupole methods; the microwave technique of electron spin resonance; and the Mössbauer effect. Phase transitions in various systems such as fluids, liquid crystals, and crystals, including paramagnets and ferroelectrics, are also

  7. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head ... limitations of MRI of the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is ...

  8. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses a powerful ... the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive medical test that ...

  9. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses a powerful ... Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive medical test that ...

  10. Magnetic resonance spectroscopy: clinical application in neuroradiology

    International Nuclear Information System (INIS)

    Full text: Magnetic Resonance Spectroscopy (MRS) provides a non-invasive method of studying metabolism in vivo. Magnetic resonance spectroscopy (MRS) defines neuro chemistry on a regional basis by acquiring a radiofrequency signal with chemical shift from one or many voxels or volumes previously selected on MRI. The tissue's chemical environment determines the frequency of a metabolite peak in an MRS spectrum. Candidates for MRS include: 1H, 31P, 13C, 23Na, 7Li, 19F, 14N, 15N, 17O, 39K The most commonly studied nuclei are 1H and 31P. This lecture is focused on Proton (1H) Spectroscopy. Proton MRS can be added on to conventional MR imaging protocols. It can be used to serially monitor biochemical changes in tumors, stroke, epilepsy, metabolic disorders, infections, and neurodegenerative diseases.The MR spectra do not come labeled with diagnoses. They require interpretation and should always be correlated with the MR images before making a final diagnosis. As a general rule, the single voxel, short TE technique is used to make the initial diagnosis, because the signal-to-noise is high and all metabolites are represented. Multi-voxel, long TE techniques are used to further characterize different regions of a mass and to assess brain parenchyma around or adjacent to the mass. Multi-voxel, long TE techniques are also used to assess response to therapy and to search for tumor recurrence. Each metabolite appears at a specific ppm, and each one reflects specific cellular and biochemical processes

  11. Magnetic Resonance Facility (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2012-03-01

    This fact sheet provides information about Magnetic Resonance Facility capabilities and applications at NREL's National Bioenergy Center. Liquid and solid-state analysis capability for a variety of biomass, photovoltaic, and materials characterization applications across NREL. NREL scientists analyze solid and liquid samples on three nuclear magnetic resonance (NMR) spectrometers as well as an electron paramagnetic resonance (EPR) spectrometer.

  12. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... bear denotes child-specific content. Related Articles and Media MR Angiography (MRA) Magnetic Resonance, Functional (fMRI) - Brain Head and Neck Cancer Treatment Brain Tumor Treatment Magnetic Resonance Imaging (MRI) Safety Alzheimer's Disease Head Injury Brain Tumors Images related to Magnetic ...

  13. Dental magnetic resonance imaging

    International Nuclear Information System (INIS)

    Growing distribution and utilization of digital volume tomography (DVT) extend the spectrum of clinical dental imaging. Additional diagnostic value, however, comes along with an increasing amount of radiation. In contrast, magnetic resonance imaging is a radiation free imaging technique. Furthermore, it offers a high soft tissue contrast. Morphological and numerical dental anomalies, differentiation of periapical lesions and exclusion of complications of dental diseases are field of applications for dental MRI. In addition, detection of caries and periodontal lesions and injury of inferior alveolar nerve are promising application areas in the future.

  14. Cranial magnetic resonance imaging

    International Nuclear Information System (INIS)

    Cranial Magnetic Resonance Imaging is comprehensive, well structured, and well written. The material is current and well referenced. The illustrations are good and complement the text well. The overall quality of publication is above average. The greatest attribute of the book is its readability. The author demonstrates ample skill in making complex subjects, such as MR physics and imaging of cerebral hemorrhage, easy to understand. The book closes with a detailed atlas on the anatomic appearance of the brain on MR images in the axial, coronal, and sagittal planes

  15. Magnetic Resonance Imaging Duodenoscope.

    Science.gov (United States)

    Syms, Richard R A; Young, Ian R; Wadsworth, Christopher A; Taylor-Robinson, Simon D; Rea, Marc

    2013-12-01

    A side-viewing duodenoscope capable of both optical and magnetic resonance imaging (MRI) is described. The instrument is constructed from MR-compatible materials and combines a coherent fiber bundle for optical imaging, an irrigation channel and a side-opening biopsy channel for the passage of catheter tools with a tip saddle coil for radio-frequency signal reception. The receiver coil is magnetically coupled to an internal pickup coil to provide intrinsic safety. Impedance matching is achieved using a mechanically variable mutual inductance, and active decoupling by PIN-diode switching. (1)H MRI of phantoms and ex vivo porcine liver specimens was carried out at 1.5 T. An MRI field-of-view appropriate for use during endoscopic retrograde cholangiopancreatography (ERCP) was obtained, with limited artefacts, and a signal-to-noise ratio advantage over a surface array coil was demonstrated. PMID:23807423

  16. Magnetic resonance imaging equipments

    International Nuclear Information System (INIS)

    Magnetic resonance imaging (MRI) is a new examination technique used in diagnostic medicine. Its use has increased notably during the last few years in Finland, too. The biological effects of electromagnetic fields used in MRI are quite different from the effects of x-rays. This report introduces the physics and the techniques of MRI; the biological effects of magnetic fields and the hazards associated with the use of MRI systems are briefly discussed. The major national and international recommendations are summarized, too. Furthermore, a description is given how safety aspects are considered in Finnish MRI units. Finally, recommendations are given to restrict the exposure caused by MRI and to ensure the safe use of MRI. Diagnostic applications and clinical or economic aspects fall outside the scope of this report. (orig.)

  17. Dual tuned 19F/1H multichannel coil for magnetic resonance imaging of human knee at 7.0 Tesla

    OpenAIRE

    Ji, Yiyi

    2013-01-01

    Anti-inflamatórios não esteróides (NSAIDs) tópicos foram introduzidos no tratamento da artrite reumatóide, de forma a evitar os efeitos secundários da administração oral destes medicamentos. Embora seja conhecido que os NSAIDs de aplicação tópica são capazes de penetrar na pele humana, não existem estudos com humanos in vivo que mostrem a eficiência de penetração e o percurso do medicamento até ao local de inflamação. O in vivo tracking do medicamento deve ser efectuado por um método eficaz ...

  18. Direct Comparison of 19F qNMR and 1H qNMR by Characterizing Atorvastatin Calcium Content

    Directory of Open Access Journals (Sweden)

    Yang Liu

    2016-01-01

    Full Text Available Quantitative nuclear magnetic resonance (qNMR is a powerful tool in measuring drug content because of its high speed, sensitivity, and precision. Most of the reports were based on proton qNMR (1H qNMR and only a few fluorine qNMR (19F qNMR were reported. No research has been conducted to directly compare the advantage and disadvantage between these two methods. In the present study, both 19F and 1H qNMR were performed to characterize the content of atorvastatin calcium with the same internal standard. Linearity, precision, and results from two methods were compared. Results showed that 19F qNMR has similar precision and sensitivity to 1H qNMR. Both methods generate similar results compared to mass balance method. Major advantage from 19F qNMR is that the analyte signal is with less or no interference from impurities. 19F qNMR is an excellent approach to quantify fluorine-containing analytes.

  19. Cardiovascular Magnetic Resonance Imaging

    Science.gov (United States)

    Pelc, Norbert

    2000-03-01

    Cardiovascular diseases are a major source of morbidity and mortality in the United States. Early detection of disease can often be used to improved outcomes, either through direct interventions (e.g. surgical corrections) or by causing the patient to modify his or her behavior (e.g. smoking cessation or dietary changes). Ideally, the detection process should be noninvasive (i.e. it should not be associated with significant risk). Magnetic Resonance Imaging (MRI) refers to the formation of images by localizing NMR signals, typically from protons in the body. As in other applications of NMR, a homogeneous static magnetic field ( ~0.5 to 4 T) is used to create ``longitudinal" magnetization. A magnetic field rotating at the Larmor frequency (proportional to the static field) excites spins, converting longitudinal magnetization to ``transverse" magnetization and generating a signal. Localization is performed using pulsed gradients in the static field. MRI can produce images of 2-D slices, 3-D volumes, time-resolved images of pseudo-periodic phenomena such as heart function, and even real-time imaging. It is also possible to acquire spatially localized NMR spectra. MRI has a number of advantages, but perhaps the most fundamental is the richness of the contrast mechanisms. Tissues can be differentiated by differences in proton density, NMR properties, and even flow or motion. We also have the ability to introduce substances that alter NMR signals. These contrast agents can be used to enhance vascular structures and measure perfusion. Cardiovascular MRI allows the reliable diagnosis of important conditions. It is possible to image the blood vessel tree, quantitate flow and perfusion, and image cardiac contraction. Fundamentally, the power of MRI as a diagnostic tool stems from the richness of the contrast mechanisms and the flexibility in control of imaging parameters.

  20. Advances in magnetic resonance 11

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 11, presents a variety of contributions to the theory and practice of magnetic resonance. The book contains three chapters and begins with a discussion of the principles and applications of dynamic nuclear polarization, with emphasis on molecular motions and collisions, intermolecular couplings, and chemical interactions. Subsequent chapters focus on the assessment of a proposed broadband decoupling method and studies of time-domain (or Fourier transform) multiple-quantum nuclear magnetic resonance.

  1. Detection of site-specific binding and co-binding of ligands to macromolecules using sup 19 F NMR

    Energy Technology Data Exchange (ETDEWEB)

    Jenkins, B.G. (Massachusetts General Hospital and Harvard Medical School, Charlestown (USA))

    1991-01-01

    Study of ligand-macromolecular interactions by {sup 19}F nuclear magnetic resonance (NMR) spectroscopy affords many opportunities for obtaining molecular biochemical and pharmaceutical information. This is due to the absence of a background fluorine signal, as well as the relatively high sensitivity of {sup 19}F NMR. Use of fluorine-labeled ligands enables one to probe not only binding and co-binding phenomena to macromolecules, but also can provide data on binding constants, stoichiometries, kinetics, and conformational properties of these complexes. Under conditions of slow exchange and macromolecule-induced chemical shifts, multiple {sup 19}F NMR resonances can be observed for free and bound ligands. These shifted resonances are a direct correlate of the concentration of ligand bound in a specific state rather than the global concentrations of bound or free ligand which are usually determined using other techniques such as absorption spectroscopy or equilibrium dialysis. Examples of these interactions are demonstrated both from the literature and from interactions of 5-fluorotryptophan, 5-fluorosalicylic acid, flurbiprofen, and sulindac sulfide with human serum albumin. Other applications of {sup 19}F NMR to study of these interactions in vivo, as well for receptor binding and metabolic tracing of fluorinated drugs and proteins are discussed.

  2. Advances in magnetic resonance 6

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 6 focuses on the theoretical and practical aspects of applying magnetic resonance methods to various problems in physical chemistry, emphasizing the different aspects of the exegesis of these problems. This book discusses the gas phase magnetic resonance of electronically excited molecules; techniques for observing excited electronic states; NMR studies in liquids at high pressure; and effect of pressure on self-diffusion in liquids. The nuclear magnetic resonance investigations of organic free radicals; measurement of proton coupling constants by NMR; an

  3. Conformational Plasticity of the NNRTI-Binding Pocket in HIV-1 Reverse Transcriptase: A Fluorine Nuclear Magnetic Resonance Study.

    Science.gov (United States)

    Sharaf, Naima G; Ishima, Rieko; Gronenborn, Angela M

    2016-07-19

    HIV-1 reverse transcriptase (RT) is a major drug target in the treatment of HIV-1 infection. RT inhibitors currently in use include non-nucleoside, allosteric RT inhibitors (NNRTIs), which bind to a hydrophobic pocket, distinct from the enzyme's active site. We investigated RT-NNRTI interactions by solution (19)F nuclear magnetic resonance (NMR), using singly (19)F-labeled RT proteins. Comparison of (19)F chemical shifts of fluorinated RT and drug-resistant variants revealed that the fluorine resonance is a sensitive probe for identifying mutation-induced changes in the enzyme. Our data show that in the unliganded enzyme, the NNRTI-binding pocket is highly plastic and not locked into a single conformation. Upon inhibitor binding, the binding pocket becomes rigidified. In the inhibitor-bound state, the (19)F signal of RT is similar to that of drug-resistant mutant enzymes, distinct from what is observed for the free state. Our results demonstrate the power of (19)F NMR spectroscopy to characterize conformational properties using selectively (19)F-labeled protein.

  4. Conformational Plasticity of the NNRTI-Binding Pocket in HIV-1 Reverse Transcriptase: A Fluorine Nuclear Magnetic Resonance Study.

    Science.gov (United States)

    Sharaf, Naima G; Ishima, Rieko; Gronenborn, Angela M

    2016-07-19

    HIV-1 reverse transcriptase (RT) is a major drug target in the treatment of HIV-1 infection. RT inhibitors currently in use include non-nucleoside, allosteric RT inhibitors (NNRTIs), which bind to a hydrophobic pocket, distinct from the enzyme's active site. We investigated RT-NNRTI interactions by solution (19)F nuclear magnetic resonance (NMR), using singly (19)F-labeled RT proteins. Comparison of (19)F chemical shifts of fluorinated RT and drug-resistant variants revealed that the fluorine resonance is a sensitive probe for identifying mutation-induced changes in the enzyme. Our data show that in the unliganded enzyme, the NNRTI-binding pocket is highly plastic and not locked into a single conformation. Upon inhibitor binding, the binding pocket becomes rigidified. In the inhibitor-bound state, the (19)F signal of RT is similar to that of drug-resistant mutant enzymes, distinct from what is observed for the free state. Our results demonstrate the power of (19)F NMR spectroscopy to characterize conformational properties using selectively (19)F-labeled protein. PMID:27163463

  5. Magnetic resonance in neuroborreliosis

    International Nuclear Information System (INIS)

    Magnetic resonance (MR) is commonly used in diagnosing infections of the central nervous system. The aim of the study is to evaluate central nervous system changes in neuroborreliosis patients. MR examinations were performed in 44 patients with clinical symptoms, epidemiology and laboratory tests results of neuroborreliosis. Abnormalities were detected in 22 patients. Most of them presented cortico-subcortical atrophy (86%). In 9 cases foci of increased signal in T2-weighted and FLAIR images were observed in white matter. They were single or multiple, located subcorticaly and paraventriculary. In 2 subjects areas of increased signal were found in the brain stem. Central nervous system abnormalities detected with MR are not specific for Lyme disease. They can suggest demyelinating lesions and/or gliosis observed in many nervous system disorders (SM, ADEM, lacunar infarcts). (author)

  6. Advances in magnetic resonance 12

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 12, presents a variety of contributions to the theory and practice of magnetic resonance. The book contains six chapters and begins with a discussion of diffusion and self-diffusion measurements by nuclear magnetic resonance. This is followed by separate chapters on spin-lattice relaxation time in hydrogen isotope mixtures; the principles of optical detection of nuclear spin alignment and nuclear quadropole resonance; and the spin-1 behavior, including the relaxation of the quasi-invariants of the motion of a system of pairs of dipolar coupled spin-1/2 nu

  7. CHARACTERIZATION OF TANK 19F SAMPLES

    Energy Technology Data Exchange (ETDEWEB)

    Oji, L.; Diprete, D.; Click, D.

    2009-12-17

    The Savannah River National Laboratory (SRNL) was asked by Liquid Waste Operations to characterize Tank 19F closure samples. Tank 19F slurry samples analyzed included the liquid and solid fractions derived from the slurry materials along with the floor scrape bottom Tank 19F wet solids. These samples were taken from Tank 19F in April 2009 and made available to SRNL in the same month. Because of limited amounts of solids observed in Tank 19F samples, the samples from the north quadrants of the tank were combined into one Tank 19F North Hemisphere sample and similarly the south quadrant samples were combined into one Tank 19F South Hemisphere sample. These samples were delivered to the SRNL shielded cell. The Tank 19F samples were analyzed for radiological, chemical and elemental components. Where analytical methods yielded additional contaminants other than those requested by the customer, these results were also reported. The target detection limits for isotopes analyzed were based on detection values of 1E-04 {micro}Ci/g for most radionuclides and customer desired detection values of 1E-05 {micro}Ci/g for I-129, Pa-231, Np-237, and Ra-226. While many of the target detection limits, as specified in the technical task request and task technical and quality assurance plans were met for the species characterized for Tank 19F, some were not met. In a number of cases, the relatively high levels of radioactive species of the same element or a chemically similar element precluded the ability to measure some isotopes to low levels. SRNL, in conjunction with the plant customer, reviewed all these cases and determined that the impacts were negligible.

  8. (19)F MRSI of capecitabine in the liver at 7 T using broadband transmit-receive antennas and dual-band RF pulses.

    Science.gov (United States)

    van Gorp, Jetse S; Seevinck, Peter R; Andreychenko, Anna; Raaijmakers, Alexander J E; Luijten, Peter R; Viergever, Max A; Koopman, Miriam; Boer, Vincent O; Klomp, Dennis W J

    2015-11-01

    Capecitabine (Cap) is an often prescribed chemotherapeutic agent, successfully used to cure some patients from cancer or reduce tumor burden for palliative care. However, the efficacy of the drug is limited, it is not known in advance who will respond to the drug and it can come with severe toxicity. (19)F Magnetic Resonance Spectroscopy (MRS) and Magnetic Resonance Spectroscopic Imaging (MRSI) have been used to non-invasively study Cap metabolism in vivo to find a marker for personalized treatment. In vivo detection, however, is hampered by low concentrations and the use of radiofrequency (RF) surface coils limiting spatial coverage. In this work, the use of a 7T MR system with radiative multi-channel transmit-receive antennas was investigated with the aim of maximizing the sensitivity and spatial coverage of (19)F detection protocols. The antennas were broadband optimized to facilitate both the (1)H (298 MHz) and (19)F (280 MHz) frequencies for accurate shimming, imaging and signal combination. B1(+) simulations, phantom and noise measurements showed that more than 90% of the theoretical maximum sensitivity could be obtained when using B1(+) and B1(-) information provided at the (1)H frequency for the optimization of B1(+) and B1(-) at the (19)F frequency. Furthermore, to overcome the limits in maximum available RF power, whilst ensuring simultaneous excitation of all detectable conversion products of Cap, a dual-band RF pulse was designed and evaluated. Finally, (19)F MRS(I) measurements were performed to detect (19)F metabolites in vitro and in vivo. In two patients, at 10 h (patient 1) and 1 h (patient 2) after Cap intake, (19)F metabolites were detected in the liver and the surrounding organs, illustrating the potential of the set-up for in vivo detection of metabolic rates and drug distribution in the body.

  9. Mapping In Vivo Tumor Oxygenation within Viable Tumor by 19F-MRI and Multispectral Analysis

    Directory of Open Access Journals (Sweden)

    Yunzhou Shi

    2013-11-01

    Full Text Available Quantifying oxygenation in viable tumor remains a major obstacle toward a better understanding of the tumor microenvironment and improving treatment strategies. Current techniques are often complicated by tumor heterogeneity. Herein, a novel in vivo approach that combines 19F magnetic resonance imaging (19F-MRIR1 mapping with diffusionbased multispectral (MS analysis is introduced. This approach restricts the partial pressure of oxygen (pO2 measurements to viable tumor, the tissue of therapeutic interest. The technique exhibited sufficient sensitivity to detect a breathing gas challenge in a xenograft tumor model, and the hypoxic region measured by MS 19F-MRI was strongly correlated with histologic estimates of hypoxia. This approach was then applied to address the effects of antivascular agents on tumor oxygenation, which is a research question that is still under debate. The technique was used to monitor longitudinal pO2 changes in response to an antibody to vascular endothelial growth factor (B20.4.1.1 and a selective dual phosphoinositide 3-kinase/mammalian target of rapamycin inhibitor (GDC-0980. GDC-0980 reduced viable tumor pO2 during a 3-day treatment period, and a significant reduction was also produced by B20.4.1.1. Overall, this method provides an unprecedented view of viable tumor pO2 and contributes to a greater understanding of the effects of antivascular therapies on the tumor's microenvironment.

  10. Magnetic Resonance Studies of Energy Storage Materials

    Science.gov (United States)

    Vazquez Reina, Rafael

    In today's society there is high demand to have access to energy for portable devices in different forms. Capacitors with high performance in small package to achieve high charge/discharge rates, and batteries with their ability to store electricity and make energy mobile are part of this demand. The types of internal dielectric material strongly affect the characteristics of a capacitor, and its applications. In a battery, the choice of the electrolyte plays an important role in the Solid Electrolyte Interphase (SEI) formation, and the cathode material for high output voltage. Electron Paramagnetic Resonance (EPR) and Nuclear Magnetic Resonance (NMR) spectroscopy are research techniques that exploit the magnetic properties of the electron and certain atomic nuclei to determine physical and chemical properties of the atoms or molecules in which they are contained. Both EPR and NMR spectroscopy technique can yield meaningful structural and dynamic information. Three different projects are discussed in this dissertation. First, High energy density capacitors where EPR measurements described herein provide an insight into structural and chemical differences in the dielectric material of a capacitor. Next, as the second project, Electrolyte solutions where an oxygen-17 NMR study has been employed to assess the degree of preferential solvation of Li+ ions in binary mixtures of EC (ethylene carbonate) and DMC (dimethyl carbonate) containing LiPF6 (lithium hexafluo-rophosphate) which may be ultimately related to the SEI formation mechanism. The third project was to study Bismuth fluoride as cathode material for rechargeable batteries. The objective was to study 19F and 7Li MAS NMR of some nanocomposite cathode materials as a conversion reaction occurring during lithiation and delithation of the BiF3/C nanocomposite.

  11. Advances in magnetic resonance 1

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 1, discusses developments in various areas of magnetic resonance. The subject matter ranges from original theoretical contributions through syntheses of points of view toward series of phenomena to critical and painstaking tabulations of experimental data. The book contains six chapters and begins with a discussion of the theory of relaxation processes. This is followed by separate chapters on the development of magnetic resonance techniques for studying rate processes in chemistry and the application of these techniques to various problems; the geometri

  12. Advances in magnetic resonance 9

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 9 describes the magnetic resonance in split constants and dipolar relaxation. This book discusses the temperature-dependent splitting constants in the ESR spectra of organic free radicals; temperature-dependent splittings in ion pairs; and magnetic resonance induced by electrons. The electron impact excitation of atoms and molecules; intramolecular dipolar relaxation in multi-spin systems; and dipolar cross-correlation problem are also elaborated. This text likewise covers the NMR studies of molecules oriented in thermotropic liquid crystals and diffusion

  13. Functional magnetic resonance imaging.

    Science.gov (United States)

    Buchbinder, Bradley R

    2016-01-01

    Functional magnetic resonance imaging (fMRI) maps the spatiotemporal distribution of neural activity in the brain under varying cognitive conditions. Since its inception in 1991, blood oxygen level-dependent (BOLD) fMRI has rapidly become a vital methodology in basic and applied neuroscience research. In the clinical realm, it has become an established tool for presurgical functional brain mapping. This chapter has three principal aims. First, we review key physiologic, biophysical, and methodologic principles that underlie BOLD fMRI, regardless of its particular area of application. These principles inform a nuanced interpretation of the BOLD fMRI signal, along with its neurophysiologic significance and pitfalls. Second, we illustrate the clinical application of task-based fMRI to presurgical motor, language, and memory mapping in patients with lesions near eloquent brain areas. Integration of BOLD fMRI and diffusion tensor white-matter tractography provides a road map for presurgical planning and intraoperative navigation that helps to maximize the extent of lesion resection while minimizing the risk of postoperative neurologic deficits. Finally, we highlight several basic principles of resting-state fMRI and its emerging translational clinical applications. Resting-state fMRI represents an important paradigm shift, focusing attention on functional connectivity within intrinsic cognitive networks. PMID:27432660

  14. Magnetic resonance energy and topological resonance energy.

    Science.gov (United States)

    Aihara, Jun-Ichi

    2016-04-28

    Ring-current diamagnetism of a polycyclic π-system is closely associated with thermodynamic stability due to the individual circuits. Magnetic resonance energy (MRE), derived from the ring-current diamagnetic susceptibility, was explored in conjunction with graph-theoretically defined topological resonance energy (TRE). For many aromatic molecules, MRE is highly correlative with TRE with a correlation coefficient of 0.996. For all π-systems studied, MRE has the same sign as TRE. The only trouble with MRE may be that some antiaromatic and non-alternant species exhibit unusually large MRE-to-TRE ratios. This kind of difficulty can in principle be overcome by prior geometry-optimisation or by changing spin multiplicity. Apart from the semi-empirical resonance-theory resonance energy, MRE is considered as the first aromatic stabilisation energy (ASE) defined without referring to any hypothetical polyene reference.

  15. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... is not harmful, but it may cause some medical devices to malfunction. Most orthopedic implants pose no ... Head? Magnetic resonance imaging (MRI) is a noninvasive medical test that physicians use to diagnose and treat ...

  16. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - ...

  17. Magnetic resonance imaging the basics

    CERN Document Server

    Constantinides, Christakis

    2014-01-01

    Magnetic resonance imaging (MRI) is a rapidly developing field in basic applied science and clinical practice. Research efforts in this area have already been recognized with five Nobel prizes awarded to seven Nobel laureates in the past 70 years. Based on courses taught at The Johns Hopkins University, Magnetic Resonance Imaging: The Basics provides a solid introduction to this powerful technology. The book begins with a general description of the phenomenon of magnetic resonance and a brief summary of Fourier transformations in two dimensions. It examines the fundamental principles of physics for nuclear magnetic resonance (NMR) signal formation and image construction and provides a detailed explanation of the mathematical formulation of MRI. Numerous image quantitative indices are discussed, including (among others) signal, noise, signal-to-noise, contrast, and resolution. The second part of the book examines the hardware and electronics of an MRI scanner and the typical measurements and simulations of m...

  18. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... Magnetic resonance imaging (MRI) is a noninvasive medical test that physicians use to diagnose and treat medical ... CD. Currently, MRI is the most sensitive imaging test of the head (particularly the brain) in routine ...

  19. Advances in magnetic resonance 2

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 2, features a mixture of experimental and theoretical contributions. The book contains four chapters and begins with an ambitious and general treatment of the problem of signal-to-noise ratio in magnetic resonance. This is followed by separate chapters on the interpretation of nuclear relaxation in fluids, with special reference to hydrogen; and various aspects of molecular theory of importance in NMR.

  20. Advances in magnetic resonance 4

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 4 deals with the relaxation, irradiation, and other dynamical effects that is specific to systems having resolved structure in their magnetic resonance spectra. This book discusses the anisotropic rotation of molecules in liquids by NMR quadrupolar relaxation; rotational diffusion constants; alternating linewidth effect; and theoretical formulations of the problem. The line shapes in high-resolution NMR; matrix representations of the equations of motion; matrix representations of the equations of motion; and intramolecular hydrogen bonds are also delibera

  1. Intraoperative magnetic resonance imaging.

    Science.gov (United States)

    Hall, Walter A; Truwit, Charles L

    2011-01-01

    Neurosurgeons have become reliant on image-guidance to perform safe and successful surgery both time-efficiently and cost-effectively. Neuronavigation typically involves either rigid (frame-based) or skull-mounted (frameless) stereotactic guidance derived from computed tomography (CT) or magnetic resonance imaging (MRI) that is obtained days or immediately before the planned surgical procedure. These systems do not accommodate for brain shift that is unavoidable once the cranium is opened and cerebrospinal fluid is lost. Intraoperative MRI (ioMRI) systems ranging in strength from 0.12 to 3 Tesla (T) have been developed in part because they afford neurosurgeons the opportunity to accommodate for brain shift during surgery. Other distinct advantages of ioMRI include the excellent soft tissue discrimination, the ability to view the surgical site in three dimensions, and the ability to "see" tumor beyond the surface visualization of the surgeon's eye, either with or without a surgical microscope. The enhanced ability to view the tumor being biopsied or resected allows the surgeon to choose a safe surgical corridor that avoids critical structures, maximizes the extent of the tumor resection, and confirms that an intraoperative hemorrhage has not resulted from surgery. Although all ioMRI systems allow for basic T1- and T2-weighted imaging, only high-field (>1.5 T) MRI systems are capable of MR spectroscopy (MRS), MR angiography (MRA), MR venography (MRV), diffusion-weighted imaging (DWI), and brain activation studies. By identifying vascular structures with MRA and MRV, it may be possible to prevent their inadvertent injury during surgery. Biopsying those areas of elevated phosphocholine on MRS may improve the diagnostic yield for brain biopsy. Mapping out eloquent brain function may influence the surgical path to a tumor being resected or biopsied. The optimal field strength for an ioMRI-guided surgical system and the best configuration for that system are as yet

  2. Magnetic Resonance Imaging of Thoracic Aortic Dissections

    OpenAIRE

    Sax, Steven L.

    1990-01-01

    Magnetic resonance imaging is an excellent noninvasive method for evaluating thoracic aortic dissections. A variety of magnetic resonance scans of aortic dissections are shown, documenting the ability of magnetic resonance to image the true lumen, the false channel, and the intimal septum. Detail is provided on magnetic resonance imaging techniques and findings. (Texas Heart Institute Journal 1990;17:262-70)

  3. Advances in magnetic resonance 5

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 5 deals with the interpretation of ESR spectra and provides descriptions of experimental apparatus. This book discusses the halogen hyperfine interactions; organic radicals in single crystals; pulsed-Fourier-transform nuclear magnetic resonance spectrometer; and inhomogenizer and decoupler. The spectrometers for multiple-pulse NMR; weak collision theory of relaxation in the rotating frame; and spin Hamiltonian for the electron spin resonance of irradiated organic single crystals are also deliberated. This text likewise covers the NMR in helium three and m

  4. Parity nonconservation in /sup 19/F nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Elsener, K.; Gruebler, W.; Koenig, V.; Schmelzbach, P.A.; Ulbricht, J.; Vuaridel, B.; Singy, D.; Forstner, C.; Zhang, W.Z.

    1987-01-12

    The parity nonconserving asymmetry A/sub ..gamma../ in the decay of polarized /sup 19/F/sup */(110 keV) nuclei has been measured. A value of A/sub ..gamma../=-(6.83 +- 2.11) x 10/sup -5/ (total error) was found. Systematic errors are extensively investigated and found to be small. The absolute normalization is given by the /sup 19/F/sup */ polarization, which is found to be rho/sub F/=-0.52 +- 0.08 in a separate experiment, using a calibrated Compton polarimeter. The new result A/sub ..gamma../(/sup 19/F) is compared to earlier experiments and recent theoretical calculations. From an analysis including /sup 18/F and /sup 21/Ne results, constraints on the weak meson-nucleon coupling constants f/sub ..pi../ and h/sub rho//sup 0/ are deduced. Agreement with calculations based on the standard electroweak theory and QCD is found.

  5. GHz nuclear magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Cross, T.A.; Drobny, G.; Trewhella, J.

    1994-12-01

    For the past dozen years, 500- and 600-MHz spectrometers have become available in many laboratories. The first 600-MHz NMR spectrometer (at Carnegie Mellon University) was commissioned more than 15 years ago and, until 1994, represented the highest field available for high-resolution NMR. This year, we have witnessed unprecedented progress in the development of very high field magnets for NMR spectroscopy, including the delivery of the first commercial 750-MHz NMR spectrometers. In addition, NMR signals have been obtained from 20-Tesla magnets (850 MHz for {sup 1}H`s) at both Los Alamos National Laboratory and Florida State University in the NHMFL (National High Magnetic Field Laboratory). These preliminary experiments have been performed in magnets with 100-ppm homogeneity, but a 20-Tesla magnet developed for the NHMFL will be brought to field this year with a projected homogeneity of 0.1 ppm over a 1-cm-diam spherical volume.

  6. In Vivo Quantification of Inflammation in Experimental Autoimmune Encephalomyelitis Rats Using Fluorine-19 Magnetic Resonance Imaging Reveals Immune Cell Recruitment outside the Nervous System.

    Directory of Open Access Journals (Sweden)

    Jia Zhong

    Full Text Available Progress in identifying new therapies for multiple sclerosis (MS can be accelerated by using imaging biomarkers of disease progression or abatement in model systems. In this study, we evaluate the ability to noninvasively image and quantitate disease pathology using emerging "hot-spot" 19F MRI methods in an experimental autoimmune encephalomyelitis (EAE rat, a model of MS. Rats with clinical symptoms of EAE were compared to control rats without EAE, as well as to EAE rats that received daily prophylactic treatments with cyclophosphamide. Perfluorocarbon (PFC nanoemulsion was injected intravenously, which labels predominately monocytes and macrophages in situ. Analysis of the spin-density weighted 19F MRI data enabled quantification of the apparent macrophage burden in the central nervous system and other tissues. The in vivo MRI results were confirmed by extremely high-resolution 19F/1H magnetic resonance microscopy in excised tissue samples and histopathologic analyses. Additionally, 19F nuclear magnetic resonance spectroscopy of intact tissue samples was used to assay the PFC biodistribution in EAE and control rats. In vivo hot-spot 19F signals were detected predominantly in the EAE spinal cord, consistent with the presence of inflammatory infiltrates. Surprising, prominent 19F hot-spots were observed in bone-marrow cavities adjacent to spinal cord lesions; these were not observed in control animals. Quantitative evaluation of cohorts receiving cyclophosphamide treatment displayed significant reduction in 19F signal within the spinal cord and bone marrow of EAE rats. Overall, 19F MRI can be used to quantitatively monitored EAE disease burden, discover unexpected sites of inflammatory activity, and may serve as a sensitive biomarker for the discovery and preclinical assessment of novel MS therapeutic interventions.

  7. magnetic resonance imaging,etc.

    Institute of Scientific and Technical Information of China (English)

    张福基

    1998-01-01

    magnetic resonance imaging n.[1984] a noninvasive diagnostic technique that produces computerized images of internal body tissues and is based on nuclear magnetic resonance of atoms within he body induced by the application of radio waves磁共振成像(指一种非侵害 性诊断技术,能生成内部身体组织的计算机化影像,其依据是应用无线电波 感生体内原子并使之产磁共振)

  8. Advances in magnetic resonance 8

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 8 describes the magnetic resonance in spin polarization and saturation transfer. This book discusses the theory of chemically induced dynamic spin polarization; basic results for the radical-pair mechanism; and optical spin polarization in molecular crystals. The theory of optical electronic polarization (OEP); NMR in flowing systems; and applications of NMR in a flowing liquid are also elaborated. This text likewise covers the saturation transfer spectroscopy; studies of spin labels in the intermediate and fast motion regions; and spin-density matrix and

  9. Paramagnetic fluorinated nanoemulsions for sensitive cellular fluorine-19 magnetic resonance imaging

    Science.gov (United States)

    Kislukhin, Alexander A.; Xu, Hongyan; Adams, Stephen R.; Narsinh, Kazim H.; Tsien, Roger Y.; Ahrens, Eric T.

    2016-06-01

    Fluorine-19 magnetic resonance imaging (19F MRI) probes enable quantitative in vivo detection of cell therapies and inflammatory cells. Here, we describe the formulation of perfluorocarbon-based nanoemulsions with improved sensitivity for cellular MRI. Reduction of the 19F spin-lattice relaxation time (T1) enables rapid imaging and an improved signal-to-noise ratio, thereby improving cell detection sensitivity. We synthesized metal-binding β-diketones conjugated to linear perfluoropolyether (PFPE), formulated these fluorinated ligands as aqueous nanoemulsions, and then metallated them with various transition and lanthanide ions in the fluorous phase. Iron(III) tris-β-diketonate (`FETRIS’) nanoemulsions with PFPE have low cytotoxicity (<20%) and superior MRI properties. Moreover, the 19F T1 can readily be reduced by an order of magnitude and tuned by stoichiometric modulation of the iron concentration. The resulting 19F MRI detection sensitivity is enhanced by three- to fivefold over previously used tracers at 11.7 T, and is predicted to increase by at least eightfold at the clinical field strength of 3 T.

  10. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... structures of the brain and can also provide functional information (fMRI) in selected cases. MR images of ... Articles and Media MR Angiography (MRA) Magnetic Resonance, Functional (fMRI) - Brain Head and Neck Cancer Treatment Brain ...

  11. Advances in magnetic and optical resonance

    CERN Document Server

    Warren, Warren S

    1997-01-01

    Since 1965, Advances in Magnetic and Optical Resonance has provided researchers with timely expositions of fundamental new developments in the theory of, experimentation with, and application of magnetic and optical resonance.

  12. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Science.gov (United States)

    ... produced by: Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography (MRA) Transcript Welcome to Radiology Info dot ... I’d like to talk with you about magnetic resonance angiography, or as it’s commonly known, MRA. MRA ...

  13. Magnetometer of nuclear magnetic resonance

    International Nuclear Information System (INIS)

    We present a nuclear magnetic resonance magnetometer that measures magnetic fields, between 2,500 gauss and 5,000 gauss, with an accuracy of a few parts per million. The circuit of the magnetometer, based on a marginal oscillator, permits a continuous tunning in the frequency range comprised between 10.0 MHz, with a signal to noise ratio of about 20. The radiofrequency amplifier is of the cascode type in integrated circuit and it operates with two 9V batteries. The modulation is at 35 Hz and it is provided by an external oscillator. The instrument is compact, inexpensive and easy to operate; it can also be used for didactic purposes to show the phenomenon of magnetic nuclear resonance and its main characteristics. (author)

  14. Optically detected magnetic resonance imaging

    International Nuclear Information System (INIS)

    Optically detected magnetic resonance provides ultrasensitive means to detect and image a small number of electron and nuclear spins, down to the single spin level with nanoscale resolution. Despite the significant recent progress in this field, it has never been combined with the power of pulsed magnetic resonance imaging techniques. Here, we demonstrate how these two methodologies can be integrated using short pulsed magnetic field gradients to spatially encode the sample. This result in what we denote as an 'optically detected magnetic resonance imaging' technique. It offers the advantage that the image is acquired in parallel from all parts of the sample, with well-defined three-dimensional point-spread function, and without any loss of spectroscopic information. In addition, this approach may be used in the future for parallel but yet spatially selective efficient addressing and manipulation of the spins in the sample. Such capabilities are of fundamental importance in the field of quantum spin-based devices and sensors

  15. Pediatric Body Magnetic Resonance Imaging.

    Science.gov (United States)

    Kandasamy, Devasenathipathy; Goyal, Ankur; Sharma, Raju; Gupta, Arun Kumar

    2016-09-01

    Magnetic resonance imaging (MRI) is a radiation-free imaging modality with excellent contrast resolution and multiplanar capabilities. Since ionizing radiation is an important concern in the pediatric population, MRI serves as a useful alternative to computed tomography (CT) and also provides additional clues to diagnosis, not discernible on other investigations. Magnetic resonance cholangiopancreatography (MRCP), urography, angiography, enterography, dynamic multiphasic imaging and diffusion-weighted imaging provide wealth of information. The main limitations include, long scan time, need for sedation/anesthesia, cost and lack of widespread availability. With the emergence of newer sequences and variety of contrast agents, MRI has become a robust modality and may serve as a one-stop shop for both anatomical and functional information. PMID:26916887

  16. Evanescent Waves Nuclear Magnetic Resonance

    DEFF Research Database (Denmark)

    Halidi, El Mohamed; Nativel, Eric; Akel, Mohamad;

    2016-01-01

    Nuclear Magnetic Resonance spectroscopy and imaging can be classified as inductive techniques working in the near- to far-field regimes. We investigate an alternative capacitive detection with the use of micrometer sized probes positioned at sub wavelength distances of the sample in order to char...... a new road to a better understanding of the evanescent waves component in NMR with the opportunity to perform localized spectroscopy and imaging....

  17. Ultra-high frequency magnetic resonance imaging

    OpenAIRE

    Magill, Arthur W.

    2007-01-01

    This thesis addresses the problem of radiofrequency probe design for Ultra High Frequency Magnetic Resonance Imaging (7T). The signal-to-noise ratio available in Magnetic Resonance Imaging (MRI) is determined by the static magnetic field strength, causing a continued drive toward higher fields to enable faster image acquisition at finer spatial resolution. The resonant frequency increases linearly with static field strength. At 7T the proton resonant frequency is 300MHz, with a wavelength...

  18. 19F molecular MR imaging for detection of brain tumor angiogenesis: in vivo validation using targeted PFOB nanoparticles

    International Nuclear Information System (INIS)

    Molecular imaging with magnetic resonance imaging (MRI) targeted contrast agents has emerged as a promising diagnostic approach in cancer research to detect associated bio-markers. In this work, the potential of 19F MRI was investigated to detect angiogenesis with αvβ3-targeted perfluoro-octylbromide nanoparticles (PFOB NP) in a U87 glioblastoma mouse model at 7 Tesla. Mice were injected intravenously with targeted or non-targeted NP and 19F images were immediately acquired for 90 min using a PFOB-dedicated MRI sequence. Mice infused with targeted NP exhibited higher concentrations in tumors than mice of the control group, despite the presence of nonspecific signal originating from the blood. Imaging results were corroborated by histology and fluorescence imaging, suggesting specific binding of targeted NP to αvβ3 integrin. Two other groups of mice were injected 24 h before imaging to allow blood clearance but no significant differences were found between both groups, probably due to a loss of specificity of PFOB NP. This is the first demonstration of the ability of 19F MRI to detect αvβ3 -integrin endothelial expression in brain tumors in vivo. (authors)

  19. Nuclear and astrophysical aspects of 18O(p,γ)19F

    International Nuclear Information System (INIS)

    The capture reaction 18O(p,γ)19F has been investigated in the energy range Esub(p) = 80-2200 keV. The seven known resonances have been studied in detail and twelve new resonances have been found. The resonances at Esub(R) = 680, 977 and 1670 keV correspond to new states in 19F. The known resonance at Esub(R) = 631 keV is observed to consist of a doublet (ΔEsub(p) = 7 keV). Information on resonance energies, total and partial widths, branching and mixing ratios and ωγ values is reported. Transition strength arguments as well as analyses of γ-ray angular distribution data combined with results from previous work resulted in Jsup(π) assignments for some of the resonances and low-lying states in 19F. The assignment of several states in 19F as T = 3/2 analogue states of 19O is discussed. A direct capture process to several final states in 19F up to Esub(x) = 8.8 MeV has been observed revealing information on the orbital momenta of the captured protons in the final states, their spectroscopic factors and Jsup(π) assignments for interfering resonances. Special efforts were made to detect this process to states near the proton threshold, which are of importance to stellar hydrogen burning of 18O. The results are compared with corresponding information from other reactions. The investigated energy range of the 18O(p,γ)19F reaction corresponds to the important stellar temperature range of T = 0.01 to 5 X 109 K. The energy-averaged astrophysical reaction rates determined from the present data are compared with previous estimates for this reaction. The data permit reliable conclusions to be drawn concerning the final termination of the CNO tri-cycle. (orig.)

  20. Fast magnetization reversal of nanoclusters in resonator

    OpenAIRE

    Yukalov, V. I.; Yukalova, E. P.

    2012-01-01

    An effective method for ultrafast magnetization reversal of nanoclusters is suggested. The method is based on coupling a nanocluster to a resonant electric circuit. This coupling causes the appearance of a magnetic feedback field acting on the cluster, which drastically shortens the magnetization reversal time. The influence of the resonator properties, nanocluster parameters, and external fields on the magnetization dynamics and reversal time is analyzed. The magnetization reversal time can ...

  1. Wide-range nuclear magnetic resonance detector

    Science.gov (United States)

    Sturman, J. C.; Jirberg, R. J.

    1972-01-01

    Compact and easy to use solid state nuclear magnetic resonance detector is designed for measuring field strength to 20 teslas in cryogenically cooled magnets. Extremely low noise and high sensitivity make detector applicable to nearly all types of analytical nuclear magnetic resonance measurements and can be used in high temperature and radiation environments.

  2. Solid State Multinuclear Magnetic Resonance Investigation of Electrolyte Decomposition Products on Lithium Ion Electrodes

    Science.gov (United States)

    DeSilva, J .H. S. R.; Udinwe, V.; Sideris, P. J.; Smart, M. C.; Krause, F. C.; Hwang, C.; Smith, K. A.; Greenbaum, S. G.

    2012-01-01

    Solid electrolyte interphase (SEI) formation in lithium ion cells prepared with advanced electrolytes is investigated by solid state multinuclear (7Li, 19F, 31P) magnetic resonance (NMR) measurements of electrode materials harvested from cycled cells subjected to an accelerated aging protocol. The electrolyte composition is varied to include the addition of fluorinated carbonates and triphenyl phosphate (TPP, a flame retardant). In addition to species associated with LiPF6 decomposition, cathode NMR spectra are characterized by the presence of compounds originating from the TPP additive. Substantial amounts of LiF are observed in the anodes as well as compounds originating from the fluorinated carbonates.

  3. Advances in magnetic resonance 3

    CERN Document Server

    Waugh, John S

    2013-01-01

    Advances in Magnetic Resonance, Volume 3, describes a number of important developments which are finding increasing application by chemists. The book contains five chapters and begins with a discussion of how the properties of random molecular rotations reflect themselves in NMR and how they show up, often differently, in other kinds of experiments. This is followed by separate chapters on the Kubo method, showing its equivalence to the Redfield approach in the cases of most general interest; the current state of dynamic nuclear polarization measurements in solutions and what they tell us abou

  4. Hyperpolarized Renal Magnetic Resonance Imaging

    DEFF Research Database (Denmark)

    Laustsen, Christoffer

    2016-01-01

    The introduction of dissolution dynamic nuclear polarization (d-DNP) technology has enabled a new paradigm for renal imaging investigations. It allows standard magnetic resonance imaging complementary renal metabolic and functional fingerprints within seconds without the use of ionizing radiation....... Increasing evidence supports its utility in preclinical research in which the real-time interrogation of metabolic turnover can aid the physiological and pathophysiological metabolic and functional effects in ex vivo and in vivo models. The method has already been translated to humans, although the clinical...

  5. Evanescent Waves Nuclear Magnetic Resonance.

    Science.gov (United States)

    Halidi, El Mohamed; Nativel, Eric; Akel, Mohamad; Kenouche, Samir; Coillot, Christophe; Alibert, Eric; Jabakhanji, Bilal; Schimpf, Remy; Zanca, Michel; Stein, Paul; Goze-Bac, Christophe

    2016-01-01

    Nuclear Magnetic Resonance spectroscopy and imaging can be classified as inductive techniques working in the near- to far-field regimes. We investigate an alternative capacitive detection with the use of micrometer sized probes positioned at sub wavelength distances of the sample in order to characterize and model evanescent electromagnetic fields originating from NMR phenomenon. We report that in this experimental configuration the available NMR signal is one order of magnitude larger and follows an exponential decay inversely proportional to the size of the emitters. Those investigations open a new road to a better understanding of the evanescent waves component in NMR with the opportunity to perform localized spectroscopy and imaging.

  6. Introduction to Nuclear Magnetic Resonance

    Science.gov (United States)

    Manatt, Stanley L.

    1985-01-01

    The purpose of this paper is to try to give a short overview of what the status is on nuclear magnetic resonance (NMR). It's a subject where one really has to spend some time to look at the physics in detail to develop a proper working understanding. I feel it's not appropriate to present to you density matrices, Hamiltonians of all sorts, and differential equations representing the motion of spins. I'm really going to present some history and status, and show a few very simple concepts involved in NMR. It is a form of radio frequency spectroscopy and there are a great number of nuclei that can be studied very usefully with the technique. NMR requires a magnet, a r.f. transmitter/receiver system, and a data acquisition system.

  7. Detection of psychoactive drugs using 19F MR spectroscopy

    International Nuclear Information System (INIS)

    In vivo 19F resonance spectroscopy measurements of tri fluorinated neuroleptics (flu phenazine and tri fluoperazine) and later tri fluorinated antidepressants (fluoxetine and fluvoxamine) began with animal experiments in 1983. Using rats which have been treated with high oral doses of flu phenazine over a period of three weeks at the beginning of these experiments the measurement time was very long (up to 10 h). The application of better techniques using surface coils led to a marked improvement of the signal noise ratio and measurement times in animal experiments could be reduced to minutes. These results encouraged us and other groups to perform experiments in humans to detect and try to estimate brain levels of tri fluorinated neuroleptics and antidepressants. The present data of several research groups demonstrate that 19F MR spectroscopy has the potential of becoming a valuable tool for monitoring drug levels at the site of action. The extension of the animal studies to humans might facilitate a better treatment of schizophrenic and depressive patients. (author)

  8. 1H and 19F spin-lattice relaxation and CH3 or CF3 reorientation in molecular solids containing both H and F atoms

    Science.gov (United States)

    Beckmann, Peter A.; Rheingold, Arnold L.

    2016-04-01

    The dynamics of methyl (CH3) and fluoromethyl (CF3) groups in organic molecular (van der Waals) solids can be exploited to survey their local environments. We report solid state 1H and 19F spin-lattice relaxation experiments in polycrystalline 3-trifluoromethoxycinnamic acid, along with an X-ray diffraction determination of the molecular and crystal structure, to investigate the intramolecular and intermolecular interactions that determine the properties that characterize the CF3 reorientation. The molecule is of no particular interest; it simply provides a motionless backbone (on the nuclear magnetic resonance (NMR) time scale) to investigate CF3 reorientation occurring on the NMR time scale. The effects of 19F-19F and 19F-1H spin-spin dipolar interactions on the complicated nonexponential NMR relaxation provide independent inputs into determining a model for CF3 reorientation. As such, these experiments provide much more information than when only one spin species (usually 1H) is present. In Sec. IV, which can be read immediately after the Introduction without reading the rest of the paper, we compare the barrier to CH3 and CF3 reorientation in seven organic solids and separate this barrier into intramolecular and intermolecular components.

  9. Tunable Magnetic Resonance in Microwave Spintronics Devices

    Science.gov (United States)

    Chen, Yunpeng; Fan, Xin; Xie, Yunsong; Zhou, Yang; Wang, Tao; Wilson, Jeffrey D.; Simons, Rainee N.; Chui, Sui-Tat; Xiao, John Q.

    2015-01-01

    Magnetic resonance is one of the key properties of magnetic materials for the application of microwave spintronics devices. The conventional method for tuning magnetic resonance is to use an electromagnet, which provides very limited tuning range. Hence, the quest for enhancing the magnetic resonance tuning range without using an electromagnet has attracted tremendous attention. In this paper, we exploit the huge exchange coupling field between magnetic interlayers, which is on the order of 4000 Oe and also the high frequency modes of coupled oscillators to enhance the tuning range. Furthermore, we demonstrate a new scheme to control the magnetic resonance frequency. Moreover, we report a shift in the magnetic resonance frequency as high as 20 GHz in CoFe based tunable microwave spintronics devices, which is 10X higher than conventional methods.

  10. Magnetic resonance imaging of hemochromatosis arthropathy

    International Nuclear Information System (INIS)

    This study was undertaken to compare plain film radiography and magnetic resonance imaging in the assessment of hemochromatosis arthropathy of the knees of ten patients with a biopsy-proven diagnosis. Both modalities enabled visualisation of bony degenerative changes; magnetic resonance imaging enabled additional visualization of deformity of both cartilage and menisci. Magnetic resonance imaging failed reliably to confirm the presence of intra-articular iron in the patients studied. No correlation was observed between synovial fluid magnetic resonance signal values, corresponding serum ferritin levels, or the severity of the observed degenerative changes. (orig.)

  11. Magnetic resonance imaging of hemochromatosis arthropathy

    Energy Technology Data Exchange (ETDEWEB)

    Eustace, S. [Dept. of Radiology, Deaconess Hospital and Harvard Medical School, Boston, MA (United States); Buff, B. [Dept. of Radiology, Deaconess Hospital and Harvard Medical School, Boston, MA (United States); McCarthy, C. [The Inst. of Radiological Sciences, Mater Hospital, Dublin (Ireland); MacMathuana, P. [The Inst. of Radiological Sciences, Mater Hospital, Dublin (Ireland); Gilligan, P. [The Inst. of Radiological Sciences, Mater Hospital, Dublin (Ireland); Ennis, J.T. [The Inst. of Radiological Sciences, Mater Hospital, Dublin (Ireland)

    1994-10-01

    This study was undertaken to compare plain film radiography and magnetic resonance imaging in the assessment of hemochromatosis arthropathy of the knees of ten patients with a biopsy-proven diagnosis. Both modalities enabled visualisation of bony degenerative changes; magnetic resonance imaging enabled additional visualization of deformity of both cartilage and menisci. Magnetic resonance imaging failed reliably to confirm the presence of intra-articular iron in the patients studied. No correlation was observed between synovial fluid magnetic resonance signal values, corresponding serum ferritin levels, or the severity of the observed degenerative changes. (orig.)

  12. Society for Cardiovascular Magnetic Resonance guidelines for reporting cardiovascular magnetic resonance examinations

    OpenAIRE

    van Rossum Albert C; Raman Subha V; McConnell Michael V; Lawson Mark A; Higgins Charles B; Friedrich Matthias G; Bogaert Jan G; Bluemke David; Hundley W Gregory; Flamm Scott; Kramer Christopher M; Nagel Eike; Neubauer Stefan

    2009-01-01

    Abstract These reporting guidelines are recommended by the Society for Cardiovascular Magnetic Resonance (SCMR) to provide a framework for healthcare delivery systems to disseminate cardiac and vascular imaging findings related to the performance of cardiovascular magnetic resonance (CMR) examinations.

  13. Fetal abdominal magnetic resonance imaging

    International Nuclear Information System (INIS)

    This review deals with the in vivo magnetic resonance imaging (MRI) appearance of the human fetal abdomen. Imaging findings are correlated with current knowledge of human fetal anatomy and physiology, which are crucial to understand and interpret fetal abdominal MRI scans. As fetal MRI covers a period of more than 20 weeks, which is characterized not only by organ growth, but also by changes and maturation of organ function, a different MR appearance of the fetal abdomen results. This not only applies to the fetal intestines, but also to the fetal liver, spleen, and adrenal glands. Choosing the appropriate sequences, various aspects of age-related and organ-specific function can be visualized with fetal MRI, as these are mirrored by changes in signal intensities. Knowledge of normal development is essential to delineate normal from pathological findings in the respective developmental stages

  14. Magnetic Resonance Imaging of Neurosarcoidosis

    Directory of Open Access Journals (Sweden)

    Daniel T Ginat

    2011-01-01

    Full Text Available Neurosarcoidosis is an uncommon condition with protean manifestations. Magnetic resonance imaging (MRI is often used in the diagnostic evaluation and follow-up of patients with neurosarcoidosis. Therefore, familiarity with the variety of MRI appearances is important. In this pictorial essay, the range of possible patterns of involvement in neurosarcoidosis are depicted and discussed. These include intracranial and spine leptomeningeal involvement, cortical and cerebral white matter lesions, corpus callosum involvement, sellar and suprasellar involvement, periventricular involvement, cranial nerve involvement, cavernous sinus involvement, hydrocephalus, dural involvement, ischemic lesions, perivascular involvement, orbit lesions, osseous involvement, nerve root involvement, and spinal cord intramedullary involvement. Differential diagnoses for each pattern of involvement of neurosarcoidosis are also provided.

  15. Chemical Principles Revisited. Proton Magnetic Resonance Spectroscopy.

    Science.gov (United States)

    McQuarrie, Donald A.

    1988-01-01

    Discusses how to interpret nuclear magnetic resonance (NMR) spectra and how to use them to determine molecular structures. This discussion is limited to spectra that are a result of observation of only the protons in a molecule. This type is called proton magnetic resonance (PMR) spectra. (CW)

  16. Magnetic resonance imaging of the prostate

    DEFF Research Database (Denmark)

    Iversen, P; Kjaer, L; Thomsen, C;

    1987-01-01

    Magnetic resonance imaging offers new possibilities in the investigation of the prostate. The current results of imaging and tissue discrimination in the evaluation of prostatic disease are reviewed. Magnetic resonance imaging may be of value in the staging of carcinoma of the prostate....

  17. Magnetic resonance imaging of the prostate

    DEFF Research Database (Denmark)

    Iversen, P; Kjaer, L; Thomsen, C;

    1988-01-01

    Magnetic resonance imaging offers new possibilities in investigation of the prostate gland. Current results of imaging and tissue discrimination in the evaluation of prostatic disease are reviewed. Magnetic resonance imaging may be useful in the staging of carcinoma of the prostate....

  18. Functional Magnetic Resonance Imaging and Pediatric Anxiety

    Science.gov (United States)

    Pine, Daniel S.; Guyer, Amanda E.; Leibenluft, Ellen; Peterson, Bradley S.; Gerber, Andrew

    2008-01-01

    The use of functional magnetic resonance imaging in investigating pediatric anxiety disorders is studied. Functional magnetic resonance imaging can be utilized in demonstrating parallels between the neural architecture of difference in anxiety of humans and the neural architecture of attention-orienting behavior in nonhuman primates or rodents.…

  19. Contrast agents in magnetic resonance imaging

    International Nuclear Information System (INIS)

    The origine of nuclear magnetic resonance signal is reminded and different ways for contrast enhancement in magnetic resonance imaging are presented, especially, modifications of tissus relaxation times. Investigations have focused on development of agents incorporating either paramagnetic ions or stable free radicals. Pharmacological and toxicological aspects are developed. The diagnostic potential of these substances is illustrated by the example of gadolinium complexes

  20. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... produced by: Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography (MRA) Transcript Welcome to Radiology Info dot ... I’d like to talk with you about magnetic resonance angiography, or as it’s commonly known, MRA. MRA ...

  1. Nuclear magnetic resonance studies of erythrocyte membranes

    NARCIS (Netherlands)

    Chapman, D.; Kamat, V.B.; Gier, J. de; Penkett, S.A.

    1968-01-01

    The use of nuclear magnetic resonance spectroscopy for studying molecular interactions in biological membranes has been investigated using erythrocyte membrane fragments. Sonic dispersion of these fragments produces a sharp and well-defined high-resolution nuclear magnetic resonance spectrum. The sp

  2. In situ 19F MRS measurement of RIF-1 tumor blood volume: corroboration by radioisotope-labeled [125I]-albumin and correlation to tumor size.

    Science.gov (United States)

    Baldwin, N J; Wang, Y; Ng, T C

    1996-01-01

    Tumor blood volume (TBV) is an important factor in the metabolism of a tumor and in its response to therapy. Until recently, the only methods to determine TBV were highly invasive and many involved radioisotopes. In this study, a perfluorocarbon (PFC) emulsion, Oxypherol, was monitored by 19F magnetic resonance spectroscopy (MRS). TBVs as determined by 19F MRS of in situ and excised radiation-induced fibrosarcoma (RIF-1) tumors (n = 9), were strongly correlated with the TBV measured by a radioisotope labeled albumin method (slopes of 1.1 and 0.8 with R = 0.86 and 0.91, respectively, by linear regression). In general, the TBV as calculated from the in situ MRS measurements (n = 24) decreased from 28 to 5 ml/100 g tumor mass for tumors ranging in mass from 0.15 to 2 g. However, there was an indication of an initial increase of TBV in tumors smaller than 0.5 g.

  3. Magnetic non-collinear neutron wave resonator

    CERN Document Server

    Khaidukov, Yu N

    2009-01-01

    The expression are received for amplitude of neutron reflection from layered magnetic non-collinear structure (neutron wave resonator (NWR)). It is showed the magnetic non-collinear NWR is characterized by the system of pairs of resonances for the spin flipped neutrons. The conditions are defined at which amplifying of spin-flipped neutron flux in wave resonator is multiple increased in comparison with amplifying of neutron absorption.

  4. Stepped Impedance Resonators for High Field Magnetic Resonance Imaging

    OpenAIRE

    Akgun, Can E.; DelaBarre, Lance; Yoo, Hyoungsuk; Sohn, Sung-Min; Snyder, Carl J.; Adriany, Gregor; Ugurbil, Kamil; Gopinath, Anand; Vaughan, J. Thomas

    2014-01-01

    Multi-element volume radio-frequency (RF) coils are an integral aspect of the growing field of high field magnetic resonance imaging (MRI). In these systems, a popular volume coil of choice has become the transverse electromagnetic (TEM) multi-element transceiver coil consisting of microstrip resonators. In this paper, to further advance this design approach, a new microstrip resonator strategy in which the transmission line is segmented into alternating impedance sections referred to as step...

  5. Interaction of magnetic resonators studied by the magnetic field enhancement

    OpenAIRE

    Yumin Hou

    2013-01-01

    It is the first time that the magnetic field enhancement (MFE) is used to study the interaction of magnetic resonators (MRs), which is more sensitive than previous parameters–shift and damping of resonance frequency. To avoid the coherence of lattice and the effect of Bloch wave, the interaction is simulated between two MRs with same primary phase when the distance is changed in the range of several resonance wavelengths, which is also compared with periodic structure. The calculated MFE osci...

  6. Magnetic resonance imaging in mucopolysaccharidosis

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Seijun; Tanaka, Akemi; Kawawaki, Hisashi; Hattori, Hideji; Matsuoka, Osamu; Murata, Ryosuke; Isshiki, Gen; Inoue, Yuichi

    1988-11-01

    Magnetic resonance (MR) images in six patients with mucopolysaccharidosis (MPS), two with type I S, one with type II A, two with type III B, and one with type VI MPS, were reviewed and compared with reported pathological findings and with CT scans. We used a Picker International MR imager with a 0.5-tesla superconducting magnet. The pulse sequences involved the inversion recovery technique (TR, 2,100 msec ; TI, 600 msec ; TE, 40 msec) for the T/sub 1/-weighted images and spin echo technique (TR, 1,800 msec ; TE, 120 msec) for the T/sub 2/-weighted images. The TC scanner was a Somatom 2 or DR3. In the patients with type II A and type VI MPS, there were multi-focal lesions of various sizes that showed prolonged T/sub 1/ and T/sub 2/ in the white matter. These lesions, which were not detected by CT, seemed to be correlated with the pathological findings of cavitation and dilated periadventitial space with viscous fluid. In the patients with type II A and type III B MPS, the T/sub 2/-weighted images showed a reduced contrast between gray and white matters, which may be related to the deposition of glycolipids and mucopolysaccharides in the lysosomes of the neurons and astrocytes of the gray and white matters. These findings seemed to be correlated with the clinical finding of mental retardation. In the patient of type II A MPS, there were lesions that showed prolonged T/sub 2/ of the periventricular white matter, suggesting periventricular edema. But CT hardly detected these lesions. In the patients with type I S MPS, no abnormal findings were found in MR imaging. It was concluded that MR imaging was far more sensitive for the detection of MPS lesions than CT, and was a useful method for differential diagnosis in MPS.

  7. Magnetic resonance imaging in mucopolysaccharidosis

    International Nuclear Information System (INIS)

    Magnetic resonance (MR) images in six patients with mucopolysaccharidosis (MPS), two with type I S, one with type II A, two with type III B, and one with type VI MPS, were reviewed and compared with reported pathological findings and with CT scans. We used a Picker International MR imager with a 0.5-tesla superconducting magnet. The pulse sequences involved the inversion recovery technique (TR, 2,100 msec ; TI, 600 msec ; TE, 40 msec) for the T1-weighted images and spin echo technique (TR, 1,800 msec ; TE, 120 msec) for the T2-weighted images. The TC scanner was a Somatom 2 or DR3. In the patients with type II A and type VI MPS, there were multi-focal lesions of various sizes that showed prolonged T1 and T2 in the white matter. These lesions, which were not detected by CT, seemed to be correlated with the pathological findings of cavitation and dilated periadventitial space with viscous fluid. In the patients with type II A and type III B MPS, the T2-weighted images showed a reduced contrast between gray and white matters, which may be related to the deposition of glycolipids and mucopolysaccharides in the lysosomes of the neurons and astrocytes of the gray and white matters. These findings seemed to be correlated with the clinical finding of mental retardation. In the patient of type II A MPS, there were lesions that showed prolonged T2 of the periventricular white matter, suggesting periventricular edema. But CT hardly detected these lesions. In the patients with type I S MPS, no abnormal findings were found in MR imaging. It was concluded that MR imaging was far more sensitive for the detection of MPS lesions than CT, and was a useful method for differential diagnosis in MPS. (author)

  8. Functional magnetic resonance imaging by visual stimulation

    International Nuclear Information System (INIS)

    We evaluated functional magnetic resonance images obtained in 8 healthy subjects in response to visual stimulation using a conventional clinical magnetic resonance imaging system with multi-slice spin-echo echo planar imaging. Activation in the visual cortex was clearly demonstrated by the multi-slice experiment with a task-related change in signal intensity. In addition to the primary visual cortex, other areas were also activated by a complicated visual task. Multi-slice spin-echo echo planar imaging offers high temporal resolution and allows the three-dimensional analysis of brain function. Functional magnetic resonance imaging provides a useful noninvasive method of mapping brain function. (author)

  9. Magnetic resonance in multiple sclerosis

    International Nuclear Information System (INIS)

    Magnetic Resonance Imaging was performed in more than 200 patients with clinical suspicion or knowledge of Multiple Sclerosis. One hundred and forty-seven (60 males and 87 females) had MR evidence of multiple sclerosis lesions. The MR signal of demyelinating plaques characteristically has prolonged T1 and T2 relaxation times and the T2-weighted spin-echo sequences are generally superior to the T1-weighted images because the lesions are better visualized as areas of increased signal intensity. MR is also able to detect plaques in the brainstem, cerebellum and within the cervical spinal cord. MR appears to be an important, non-invasive method for the diagnosis of Multiple Sclerosis and has proven to be diagnostically superior to CT, evoked potentials (EP) and CSF examination. In a selected group of 30 patients, with the whole battery of the relevant MS studies, MR was positive in 100%, CT in 33,3%, EP in 56% and CSF examination in 60%. In patients clinically presenting only with signs of spinal cord involvement or optic neuritis or when the clinical presentation is uncertain MR has proven to be a very useful diagnostic tool for diagnosis of MS by demonstrating unsuspected lesions in the cerebral hemispheres. (orig.)

  10. A Magnetic Resonance Measurement Technique for Rapidly Switched Gradient Magnetic Fields in a Magnetic Resonance Tomograph

    Directory of Open Access Journals (Sweden)

    K. Bartušek

    2003-01-01

    Full Text Available This paper describes a method for measuring of the gradient magnetic field in Nuclear Magnetic Resonance (NMR tomography, which is one of the modern medical diagnostic methods. A very important prerequisite for high quality imaging is a gradient magnetic field in the instrument with exactly defined properties. Nuclear magnetic resonance enables us to measure the pulse gradient magnetic field characteristics with high accuracy. These interesting precise methods were designed, realised, and tested at the Institute of Scientific Instruments (ISI of the Academy of Sciences of the Czech Republic. The first of them was the Instantaneous Frequency (IF method, which was developed into the Instantaneous Frequency of Spin Echo (IFSE and the Instantaneous Frequency of Spin Echo Series (IFSES methods. The above named methods are described in this paper and their a comparison is also presented.

  11. Enhancement of artificial magnetism via resonant bianisotropy

    Science.gov (United States)

    Markovich, Dmitry; Baryshnikova, Kseniia; Shalin, Alexander; Samusev, Anton; Krasnok, Alexander; Belov, Pavel; Ginzburg, Pavel

    2016-03-01

    All-dielectric “magnetic light” nanophotonics based on high refractive index nanoparticles allows controlling magnetic component of light at nanoscale without having high dissipative losses. The artificial magnetic optical response of such nanoparticles originates from circular displacement currents excited inside those structures and strongly depends on geometry and dispersion of optical materials. Here an approach for enhancing of magnetic response via resonant bianisotropy effect is proposed and analyzed. The key mechanism of enhancement is based on electric-magnetic interaction between two electrically and magnetically resonant nanoparticles of all-dielectric dimer. It was shown that proper geometrical arrangement of the dimer in respect to the incident illumination direction allows flexible control over all vectorial components of the magnetic moment, tailoring the latter in the dynamical range of 100% and delivering enhancement up to 36% relative to performances of standalone spherical particles. The proposed approach provides pathways for designs of all-dielectric metamaterials and metasurfaces with strong magnetic responses.

  12. Reducing Field Distortion in Magnetic Resonance Imaging

    Science.gov (United States)

    Eom, Byeong Ho; Penanen, Konstantin; Hahn, Inseob

    2010-01-01

    A concept for a magnetic resonance imaging (MRI) system that would utilize a relatively weak magnetic field provides for several design features that differ significantly from the corresponding features of conventional MRI systems. Notable among these features are a magnetic-field configuration that reduces (relative to the conventional configuration) distortion and blurring of the image, the use of a superconducting quantum interference device (SQUID) magnetometer as the detector, and an imaging procedure suited for the unconventional field configuration and sensor. In a typical application of MRI, a radio-frequency pulse is used to excite precession of the magnetic moments of protons in an applied magnetic field, and the decaying precession is detected for a short time following the pulse. The precession occurs at a resonance frequency proportional to the strengths of the magnetic field and the proton magnetic moment. The magnetic field is configured to vary with position in a known way; hence, by virtue of the aforesaid proportionality, the resonance frequency varies with position in a known way. In other words, position is encoded as resonance frequency. MRI using magnetic fields weaker than those of conventional MRI offers several advantages, including cheaper and smaller equipment, greater compatibility with metallic objects, and higher image quality because of low susceptibility distortion and enhanced spin-lattice-relaxation- time contrast. SQUID MRI is being developed into a practical MRI method for applied magnetic flux densities of the order of only 100 T

  13. DFT-GIAO calculation of properties of {sup 19}F NMR and stability study of environmentally relevant perfluoroalkylsulfonamides (PFASAmide)

    Energy Technology Data Exchange (ETDEWEB)

    Mejia-Urueta, Rafael; Mestre-Quintero, Kleyber; Vivas-Reyes, Ricardo, E-mail: rvivasr@unicartagena.edu.co [Grupo de Quimica Cuantica y Teorica, Facultad de Ciencias Exactas y Naturales, Universidad de Cartagena, Cartagena (Colombia)

    2011-09-15

    Perfluorinated organic compounds (POCs), such as perfluorooctanesulfonate (PFOS) and perfluoroalkylsulfonamide (PFASA) are compounds that have recently attracted considerable attention worldwide because of its high persistence and wide distribution in the environment. Among the spectroscopic methods used to study the PFASA, {sup 19}F nuclear magnetic resonance (NMR {sup 19}F) is very effective, due to its ability to determine concentrations of PFASA in biological samples and measure pollution in water samples. For this reason, a theoretical study of the properties of {sup 19}F NMR was performed. In this study we have determined the shielding constant ({sigma}) for different fluorine nucleus of the 18 molecules under study, using density functional theory (DFT) and GIAO method with the B3PW91/6-31+G(d,p) level of calculation. The {sigma} calculations were made at vacuum and in presence of a solvent. The values of chemical shifts ({delta}), were also calculated in a different level of theory. The best results were obtained with the level of calculation DFT-GIAO/B3PW91/6-31+G(d,p) by considering the solvent such as dimethylsulfoxide (DMSO), chloroform (CHCl{sub 3}), acetone (CH{sub 3}COCH{sub 3}) and methanol (CH{sup 3}OH). The results were interpreted in terms of calculated hardness at DFT/B3PW91/6-31+G(d, p) level. The behaviour of the hardness was higher in the molecules of four carbons PFASA than eight carbons. This explain theoretically resistance of four carbons PFAS to be transformed into perfluorobutanesulfonate (PFBS). (author)

  14. Contribution to nuclear magnetic resonance imager using permanent magnets

    International Nuclear Information System (INIS)

    After some recalls of nuclear magnetic resonance, ways to get a stable and homogeneous magnetic field are studied with permanent magnets. Development of correction coils on integrated circuits has been particularly stressed. Gradient coil specific systems have been studied taking in account ferromagnetic material presence. Antenna system has been improved and possibility of image obtention with the prototype realized has been shown

  15. International Society for Magnetic Resonance in Medicine

    Science.gov (United States)

    ... Join the ISMRM Journals History & Mission Central Office Society Award Winners Strategic Plan Policies Corporate Members Contact ... E-Library Virtual Meetings Connect With Us International Society for Magnetic Resonance in Medicine 2300 Clayton Road, ...

  16. Magnetic moment of the Roper resonance

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, T. [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet, D-55099 Mainz (Germany); Gegelia, J., E-mail: gegelia@kph.uni-mainz.de [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet, D-55099 Mainz (Germany); Institut fuer Theoretische Physik II, Ruhr-Universitaet Bochum, 44780 Bochum (Germany); High Energy Physics Institute of TSU, 0186 Tbilisi, Georgia (United States); Scherer, S. [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet, D-55099 Mainz (Germany)

    2012-08-29

    The magnetic moment of the Roper resonance is calculated in the framework of a low-energy effective field theory of the strong interactions. A systematic power-counting procedure is implemented by applying the complex-mass scheme.

  17. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... Pediatric Ultrasound Video: Angioplasty & vascular stenting Video: Arthrography Radiology and You About this Site RadiologyInfo.org is ... Explains Magnetic Resonance Angiography (MRA) Transcript Welcome to Radiology Info dot org Hello, I’m Dr. Elliot ...

  18. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... this Site RadiologyInfo.org is produced by: Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography (MRA) ... Recently posted: Focused Ultrasound for Uterine Fibroids Dementia Video: General Ultrasound Video: Pediatric Nuclear Medicine Radiology and ...

  19. Magnetic moment of the Roper resonance

    OpenAIRE

    Bauer, T.; Gegelia, J.; Scherer, S.

    2012-01-01

    The magnetic moment of the Roper resonance is calculated in the framework of a low-energy effective field theory of the strong interactions. A systematic power-counting procedure is implemented by applying the complex-mass scheme.

  20. Advanced magnetic resonance spectroscopy techniques and applications

    OpenAIRE

    Cao, Peng; 曹鹏

    2013-01-01

    Magnetic resonance (MR) is a well-known non-invasive technique that provides spectra (by MR spectroscopy, MRS) and images (by magnetic resonance imaging, MRI) of the examined tissue with detailed metabolic, structural, and functional information. This doctoral work is focused on advanced methodologies and applications of MRS for probing cellular and molecular changes in vivo. A single-voxel diffusion-weighted (DW) MRS method was first developed for monitoring the size changes of intramyocellu...

  1. Can magnetic resonance imaging differentiate undifferentiated arthritis?

    DEFF Research Database (Denmark)

    Østergaard, Mikkel; Duer, Anne; Hørslev-Petersen, K

    2005-01-01

    A high sensitivity for the detection of inflammatory and destructive changes in inflammatory joint diseases makes magnetic resonance imaging potentially useful for assigning specific diagnoses, such as rheumatoid arthritis and psoriatic arthritis in arthritides, that remain undifferentiated after...... conventional clinical, biochemical and radiographic examinations. With recent data as the starting point, the present paper describes the current knowledge on magnetic resonance imaging in the differential diagnosis of undifferentiated arthritis....

  2. Nuclear Magnetic Resonance Imaging: Current Capabilities

    OpenAIRE

    Davis, Peter L.; Crooks, Lawrence E.; Margulis, Alexander R.; Kaufman, Leon

    1982-01-01

    Nuclear magnetic resonance imaging can produce tomographic images of the body without ionizing radiation. Images of the head, chest, abdomen, pelvis and extremities have been obtained and normal structures and pathology have been identified. Soft tissue contrast with this method is superior to that with x-ray computerized tomography and its spatial resolution is approaching that of x-ray computerized tomography. In addition, nuclear magnetic resonance imaging enables us to image along the sag...

  3. Magnetic Resonance Imaging with a Dielectric Lens

    OpenAIRE

    Vazquez, F.; Marrufo, O.; MARTIN,R; Rodriguez, A. O.

    2009-01-01

    Recently, metamaterials have been introduced to improve the signal-to-noise ratio (SNR) of magnetic resonance images with very promising results. However, the use polymers in the generation of high quality images in magnetic resonance imaging has not been fully been investigated. These investigations explored the use of a dielectric periodical array as a lens to improve the image SNR generated with single surface coils. Commercial polycarbonate glazing sheets were used together with a circula...

  4. Fluorine-19 nuclear magnetic resonance and biochemical characterization of fluorotyrosine-labeled-thymidylate-synthetase

    Science.gov (United States)

    Rosson, Dan; Lewis, Charles A.; Ellis, Paul D.; Dunlap, R. Bruce

    1994-03-01

    Fluorotyrosine has been incorporated into thymidylate synthetase from Lactobacillus casei by growth of the bacterium in media containing 3-fluorotyrosine. The enzyme exhibited a specific activity 70% of that of the normal enzyme and formed a covalent binary complex with pyrimidine nucleotides, as well as a covalent ternary complex with 5-fluorodeoxyuridylate and 5,10-methylenetetrahydrofolate. 19F nuclear magnetic resonance spectroscopy has been used to follow the formation of these complexes. 5-Fluorodeoxyuridylate, dUMP, dTMP and dCMP produced identical conformational changes in the enzyme as monitored by the fluorotyrosyl resonances. Ternary complex formation of the fluorotyrosine-containing enzyme with 5-fluorodeoxyuridylate and 5,10-methylenetetrahydrofolate resulted in further spectral changes.

  5. Enhancement of artificial magnetism via resonant bianisotropy

    CERN Document Server

    Markovich, Dmitry; Shalin, Alexander; Samusev, Anton; Krasnok, Alexander; Belov, Pavel; Ginzburg, Pavel

    2015-01-01

    All-dielectric "magnetic light" nanophotonics based on high refractive index nanoparticles allows controlling magnetic component of light at nanoscale without having high dissipative losses. The artificial magnetic optical response of such nanoparticles originates from circular displacement currents excited inside those structures and strongly depends on geometry and dispersion of optical materials. Here a new approach for increasing magnetic response via resonant bianisotropy effect is proposed and analyzed. The key mechanism of enhancement is based on electric-magnetic interaction between two electrically and magnetically resonant nanoparticles of all-dielectric dimer nanoantenna. It was shown that proper geometrical arrangement of the dimer in respect to the incident illumination direction allows flexible control over all vectorial components of magnetic polarizability, tailoring the later in the dynamical range of 100 % and enhancement up to 36 % relative to performances of standalone spherical particles....

  6. NMR shielding and spin–rotation constants of {sup 175}LuX (X = {sup 19}F, {sup 35}Cl, {sup 79}Br, {sup 127}I) molecules

    Energy Technology Data Exchange (ETDEWEB)

    Demissie, Taye B. [Centre for Theoretical and Computational Chemistry Department of Chemistry, UiT – The Arctic University of Norway, N-9037 Tromsø (Norway)

    2015-12-31

    This presentation demonstrates the relativistic effects on the spin-rotation constants, absolute nuclear magnetic resonance (NMR) shielding constants and shielding spans of {sup 175}LuX (X = {sup 19}F, {sup 35}Cl, {sup 79}Br, {sup 127}I) molecules. The results are obtained from calculations performed using density functional theory (non-relativistic and four-component relativistic) and coupled-cluster calculations. The spin-rotation constants are compared with available experimental values. In most of the molecules studied, relativistic effects make an order of magnitude difference on the NMR absolute shielding constants.

  7. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... a powerful magnetic field, radio waves and a computer to produce detailed pictures of the brain and ... powerful magnetic field, radio frequency pulses and a computer to produce detailed pictures of organs, soft tissues, ...

  8. Coherence of magnetic resonators in a metamaterial

    Directory of Open Access Journals (Sweden)

    Yumin Hou

    2013-12-01

    Full Text Available The coherence of periodic magnetic resonators (MRs under oblique incidence is studied using simulations. The correlated phase of interaction including both the retardation effect and relative phase difference between two MRs is defined, and it plays a key role in the MR interaction. The correlated phase is anisotropic, as is the coherence condition. The coherence condition is the same as the Wood's anomaly and verified by the Fano resonance. This study shows that the applications of the Fano resonance of periodic MRs will become widespread owing to achieving the Fano resonance simply by tuning the incident angle.

  9. Society for Cardiovascular Magnetic Resonance guidelines for reporting cardiovascular magnetic resonance examinations

    Directory of Open Access Journals (Sweden)

    van Rossum Albert C

    2009-03-01

    Full Text Available Abstract These reporting guidelines are recommended by the Society for Cardiovascular Magnetic Resonance (SCMR to provide a framework for healthcare delivery systems to disseminate cardiac and vascular imaging findings related to the performance of cardiovascular magnetic resonance (CMR examinations.

  10. 170 Nanometer Nuclear Magnetic Resonance Imaging using Magnetic Resonance Force Microscopy

    CERN Document Server

    Thurber, K R; Smith, D D; Thurber, Kent R.; Harrell, Lee E.; Smith, Doran D.

    2003-01-01

    We demonstrate one-dimensional nuclear magnetic resonance imaging of the semiconductor GaAs with 170 nanometer slice separation and resolve two regions of reduced nuclear spin polarization density separated by only 500 nanometers. This is achieved by force detection of the magnetic resonance, Magnetic Resonance Force Microscopy (MRFM), in combination with optical pumping to increase the nuclear spin polarization. Optical pumping of the GaAs creates spin polarization up to 12 times larger than the thermal nuclear spin polarization at 5 K and 4 T. The experiment is sensitive to sample volumes containing $\\sim 4 \\times 10^{11}$ $^{71}$Ga$/\\sqrt{Hz}$. These results demonstrate the ability of force-detected magnetic resonance to apply magnetic resonance imaging to semiconductor devices and other nanostructures.

  11. Magnetic resonance imaging of iliotibial band syndrome.

    Science.gov (United States)

    Ekman, E F; Pope, T; Martin, D F; Curl, W W

    1994-01-01

    Seven cases of iliotibial band syndrome and the pathoanatomic findings of each, as demonstrated by magnetic resonance imaging, are presented. These findings were compared with magnetic resonance imaging scans of 10 age- and sex-matched control knees without evidence of lateral knee pain. Magnetic resonance imaging signal consistent with fluid was seen deep to the iliotibial band in the region of the lateral femoral epicondyle in five of the seven cases. Additionally, when compared with the control group, patients with iliotibial band syndrome demonstrated a significantly thicker iliotibial band over the lateral femoral epicondyle (P iliotibial band in the disease group was 5.49 +/- 2.12 mm, as opposed to 2.52 +/- 1.56 mm in the control group. Cadaveric dissections were performed on 10 normal knees to further elucidate the exact nature of the area under the iliotibial band. A potential space, i.e., a bursa, was found between the iliotibial band and the knee capsule. This series suggests that magnetic resonance imaging demonstrates objective evidence of iliotibial band syndrome and can be helpful when a definitive diagnosis is essential. Furthermore, correlated with anatomic dissection, magnetic resonance imaging identifies this as a problem within a bursa beneath the iliotibial band and not a problem within the knee joint.

  12. Generation of nuclear magnetic resonance images

    International Nuclear Information System (INIS)

    Two generation techniques of nuclear magnetic resonance images, the retro-projection and the direct transformation method are studied these techniques are based on the acquisition of NMR signals which phases and frequency components are codified in space by application of magnetic field gradients. The construction of magnet coils is discussed, in particular a suitable magnet geometry with polar pieces and air gap. The obtention of image contrast by T1 and T2 relaxation times reconstructed from generated signals using sequences such as spin-echo, inversion-recovery and stimulated echo, is discussed. The mathematical formalism of matrix solution for Bloch equations is also presented. (M.C.K.)

  13. Magnetic resonance of magnetic fluid and magnetoliposome preparations

    Energy Technology Data Exchange (ETDEWEB)

    Morais, Paulo C. [Universidade de Brasilia, Instituto de Fisica, Nucleo de Fisica Aplicada, 70919-970 Brasilia-DF (Brazil)]. E-mail: pcmor@unb.br; Santos, Judes G. [Universidade de Brasilia, Instituto de Fisica, Nucleo de Fisica Aplicada, 70919-970 Brasilia-DF (Brazil); Skeff Neto, K. [Universidade de Brasilia, Instituto de Fisica, Nucleo de Fisica Aplicada, 70919-970 Brasilia-DF (Brazil); Pelegrini, Fernando [Universidade Federal de Goias, Instituto de Fisica, 74001-970 Goiania-GO (Brazil); Cuyper, Marcel de [Katholieke Universiteit Leuven, Campus Kortrijk, Interdisciplinary Research Centre, B-8500 Kortrijk (Belgium)

    2005-05-15

    In this study, magnetic resonance was used to investigate lauric acid-coated magnetite-based magnetic fluid particles and particles which are surrounded by a double layer of phospholipid molecules (magnetoliposomes). The data reveal the presence of monomers and dimers in both samples. Whereas evidence for a thermally induced disruption of dimers is found in the magnetic fluid, apparently, the bilayer phospholipid envelop prevents the dissociation in the magnetoliposome samples.

  14. Magnetic resonance imaging of breast implants.

    Science.gov (United States)

    Shah, Mala; Tanna, Neil; Margolies, Laurie

    2014-12-01

    Silicone breast implants have significantly evolved since their introduction half a century ago, yet implant rupture remains a common and expected complication, especially in patients with earlier-generation implants. Magnetic resonance imaging is the primary modality for assessing the integrity of silicone implants and has excellent sensitivity and specificity, and the Food and Drug Administration currently recommends periodic magnetic resonance imaging screening for silent silicone breast implant rupture. Familiarity with the types of silicone implants and potential complications is essential for the radiologist. Signs of intracapsular rupture include the noose, droplet, subcapsular line, and linguine signs. Signs of extracapsular rupture include herniation of silicone with a capsular defect and extruded silicone material. Specific sequences including water and silicone suppression are essential for distinguishing rupture from other pathologies and artifacts. Magnetic resonance imaging provides valuable information about the integrity of silicone implants and associated complications.

  15. Magnetic resonance imaging of the body

    Energy Technology Data Exchange (ETDEWEB)

    Higgins, C.B.; Hricak, H.

    1987-01-01

    This text provides reference to magnetic resonance imaging (MRI) of the body. Beginning with explanatory chapters on the physics, instrumentation, and interpretation of MRI, it proceeds to the normal anatomy of the neck, thorax, abdomen, and pelvis. Other chapters cover magnetic resonance imaging of blood flow, the larynx, the lymph nodes, and the spine, as well as MRI in obstetrics. The text features detailed coverage of magnetic resonance imaging of numerous disorders and disease states, including neck disease, thoracic disease; breast disease; congenital and acquired heart disease; vascular disease; diseases of the liver, pancreas, and spleen; diseases of the kidney, adrenals, and retroperitoneum; diseases of the male and female pelvis; and musculoskeletal diseases. Chapters on the biological and environmental hazards of MRI, the current clinical status of MRI in comparison to other imaging modalities, and economic considerations are also included.

  16. Tutte polynomial in functional magnetic resonance imaging

    Science.gov (United States)

    García-Castillón, Marlly V.

    2015-09-01

    Methods of graph theory are applied to the processing of functional magnetic resonance images. Specifically the Tutte polynomial is used to analyze such kind of images. Functional Magnetic Resonance Imaging provide us connectivity networks in the brain which are represented by graphs and the Tutte polynomial will be applied. The problem of computing the Tutte polynomial for a given graph is #P-hard even for planar graphs. For a practical application the maple packages "GraphTheory" and "SpecialGraphs" will be used. We will consider certain diagram which is depicting functional connectivity, specifically between frontal and posterior areas, in autism during an inferential text comprehension task. The Tutte polynomial for the resulting neural networks will be computed and some numerical invariants for such network will be obtained. Our results show that the Tutte polynomial is a powerful tool to analyze and characterize the networks obtained from functional magnetic resonance imaging.

  17. MAGNETIC RESONANCE SEMIOTICS OF BREAST CANCER

    Directory of Open Access Journals (Sweden)

    S. V. Serebryakova

    2009-01-01

    Full Text Available Breast cancer (BC that is the most common malignancy in women presents an indubitable threat to their life and health. The basis for this investigation was magnetic resonance imaging (MRI data of 203 women with histologically verified malignan- cies. The patients' mean age was 53±10.2 years. The paper describes the magnetic resonance semiotics of BC; the authors have developed criteria for dynamic contrast-enhanced magnetic resonance mammography used in the differential diagnosis of nodules.Due to high soft-tissue contrast, the use of thin sections, and the possibility of examining in any projection, MRI allows one not only to accurately visualize a pathological mass as compared with X-ray mammography or ultrasound study, but also to characterize its vascularization, which is a major criteria for the differential diagnosis of benign and malignant breast nodules.

  18. Magnetic resonance signal moment determination using the Earth's magnetic field

    KAUST Repository

    Fridjonsson, Einar Orn

    2015-03-01

    We demonstrate a method to manipulate magnetic resonance data such that the moments of the signal spatial distribution are readily accessible. Usually, magnetic resonance imaging relies on data acquired in so-called k-space which is subsequently Fourier transformed to render an image. Here, via analysis of the complex signal in the vicinity of the centre of k-space we are able to access the first three moments of the signal spatial distribution, ultimately in multiple directions. This is demonstrated for biofouling of a reverse osmosis (RO) membrane module, rendering unique information and an early warning of the onset of fouling. The analysis is particularly applicable for the use of mobile magnetic resonance spectrometers; here we demonstrate it using an Earth\\'s magnetic field system.

  19. Magnetic resonance signal moment determination using the Earth's magnetic field

    Science.gov (United States)

    Fridjonsson, E. O.; Creber, S. A.; Vrouwenvelder, J. S.; Johns, M. L.

    2015-03-01

    We demonstrate a method to manipulate magnetic resonance data such that the moments of the signal spatial distribution are readily accessible. Usually, magnetic resonance imaging relies on data acquired in so-called k-space which is subsequently Fourier transformed to render an image. Here, via analysis of the complex signal in the vicinity of the centre of k-space we are able to access the first three moments of the signal spatial distribution, ultimately in multiple directions. This is demonstrated for biofouling of a reverse osmosis (RO) membrane module, rendering unique information and an early warning of the onset of fouling. The analysis is particularly applicable for the use of mobile magnetic resonance spectrometers; here we demonstrate it using an Earth's magnetic field system.

  20. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... is not harmful, but it may cause some medical devices to malfunction. Most orthopedic implants pose no risk, ... magnetic field is not harmful in itself, implanted medical devices that contain metal may malfunction or cause problems ...

  1. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... x-ray contrast material, drugs, food, or the environment, or if you have asthma. The contrast material ... are also screened for safety in the magnetic environment. Children will be given appropriately sized earplugs or ...

  2. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... magnetic field of the MRI unit, metal and electronic items are not allowed in the exam room. ... tell the technologist if you have medical or electronic devices in your body. These objects may interfere ...

  3. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... look like? The traditional MRI unit is a large cylinder-shaped tube surrounded by a circular magnet. ... still during imaging. A person who is very large may not fit into the opening of certain ...

  4. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... scanner. top of page How does the procedure work? Unlike conventional x-ray examinations and computed tomography ( ... also screened for safety in the magnetic environment. Children will be given appropriately sized earplugs or headphones ...

  5. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... MRI centers allow a friend or parent to stay in the room as long as they are also screened for safety in the magnetic environment. Children will be given appropriately sized earplugs or headphones ...

  6. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... allergies and whether there’s a possibility you are pregnant. The magnetic field is not harmful, but it ... if there is any possibility that they are pregnant. MRI has been used for scanning patients since ...

  7. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... pregnant. The magnetic field is not harmful, but it may cause some medical devices to malfunction. Most ... number of abrupt onset or long-standing symptoms. It can help diagnose conditions such as: brain tumors ...

  8. Magnetic force microscopy using tip magnetization modulated by ferromagnetic resonance

    International Nuclear Information System (INIS)

    In magnetic force microscopy (MFM), the tip–sample distance should be reduced to analyze the microscopic magnetic domain structure with high spatial resolution. However, achieving a small tip–sample distance has been difficult because of superimposition of interaction forces such as van der Waals and electrostatic forces induced by the sample surface. In this study, we propose a new method of MFM using ferromagnetic resonance (FMR) to extract only the magnetic field near the sample surface. In this method, the magnetization of a magnetic cantilever is modulated by FMR to separate the magnetic field and topographic structure. We demonstrate the modulation of the magnetization of the cantilever and the identification of the polarities of a perpendicular magnetic medium. (paper)

  9. Progress in nuclear magnetic resonance spectroscopy

    CERN Document Server

    Emsley, J W; Sutcliffe, L H

    2013-01-01

    Progress in Nuclear Magnetic Resonance Spectroscopy, Part 1 is a two-chapter text that reviews significant developments in nuclear magnetic resonance (NMR) applications.The first chapter discusses NMR studies of molecules physisorbed on homogeneous surfaces. This chapter also describes the phase changes in the adsorbed layer detected by following the variation in the NMR parameters. The second chapter examines the process to obtain a plotted, data reduced Fourier transform NMR spectrum. This chapter highlights the pitfalls that can cause a decrease in information content in a NMR spectrum. The

  10. Magnetic Resonance Imaging with a Dielectric Lens

    CERN Document Server

    Vazquez, F; Martin, R; Rodriguez, A O

    2009-01-01

    Recently, metamaterials have been introduced to improve the signal-to-noise ratio (SNR) of magnetic resonance images with very promising results. However, the use polymers in the generation of high quality images in magnetic resonance imaging has not been fully been investigated. These investigations explored the use of a dielectric periodical array as a lens to improve the image SNR generated with single surface coils. Commercial polycarbonate glazing sheets were used together with a circular coil to generate phantom images at 3 Tesla on a clinical MR imager.

  11. The progress of coronary magnetic resonance imaging

    International Nuclear Information System (INIS)

    Coronary heart disease (CHD) is a kind of disease with high morbidity and mortality. The early detection and treatment has important significance to patient. With the features of noninvasive, no radiation, good soft tissue contrast and multi parameter, and displaying anatomy in arbitrary plane, magnetic resonance imaging (MRI) was gradually applied in coronary artery imaging. In this paper, the main sequence and scanning technology of coronary MRI were reviewed, factors that affecting the quality of coronary magnetic resonance imaging were summarized, and the main advantages and disadvantages were concluded. (authors)

  12. Magnetic resonance imaging of the knee

    Energy Technology Data Exchange (ETDEWEB)

    Mink, J.H.; Reicher, M.A.; Crues, J.V.

    1987-01-01

    Introducing a comprehensive, practical guide to the use of magnetic resonance imaging (MRI) in detecting and evaluating knee disorders and planning arthroscopic surgery) This book integrates MRI findings with pertinent anatomy, physiology, and clinical signs to assist radiologists in selecting imaging protocols and interpreting scans. Detailed chapters focus on magnetic resonance imaging of the menisci and ligaments and evaluation of osteonecrosis, osteochondrosis, and osteochondritis. The authors demonstrate the potential of MRI for diagnosing various knee disorders such as arthritis, fractures, popliteal cysts, synovial disease, plicae, popliteal artery aneurysms, tumors, and bone marrow disorders.

  13. Through-space (19)F-(19)F spin-spin coupling in ortho-fluoro Z-azobenzene.

    Science.gov (United States)

    Rastogi, Shiva K; Rogers, Robert A; Shi, Justin; Brown, Christopher T; Salinas, Cindy; Martin, Katherine M; Armitage, Jacob; Dorsey, Christopher; Chun, Gao; Rinaldi, Peter; Brittain, William J

    2016-02-01

    We report through-space (TS) (19)F-(19)F coupling for ortho-fluoro-substituted Z-azobenzenes. The magnitude of the TS-coupling constant ((TS) JFF ) ranged from 2.2-5.9 Hz. Using empirical formulas reported in the literature, these coupling constants correspond to non-bonded F-F distances (dFF) of 3.0-3.5 Å. These non-bonded distances are significantly smaller than those determined by X-ray crystallography or density functional theory, which argues that simple models of (19)F-(19)F TS spin-spin coupling solely based dFF are not applicable. (1)H, (13)C and (19)F data are reported for both the E and Z isomers of ten fluorinated azobenzenes. Density functional theory [B3YLP/6-311++G(d,p)] was used to calculate (19) F chemical shifts, and the calculated values deviated 0.3-10.0 ppm compared with experimental values.

  14. Nuclear magnetic resonance of thermally oriented nuclei

    International Nuclear Information System (INIS)

    The more recent developments in the spectroscopy of Nuclear Magnetic Resonance on Oriented Nuclei (NMRON) are reviewed; both theoretical and experimental advances are summarised with applications to On-Line and Off-Line determination of magnetic dipole and electric quadrupole hyperfine parameters. Some emphasis is provided on solid state considerations with indications of where likely enhancements in technique will lead in conventional hyperfine studies. (orig.)

  15. Multi-dimensionally encoded magnetic resonance imaging

    OpenAIRE

    Lin, Fa-Hsuan

    2012-01-01

    Magnetic resonance imaging typically achieves spatial encoding by measuring the projection of a q-dimensional object over q-dimensional spatial bases created by linear spatial encoding magnetic fields (SEMs). Recently, imaging strategies using nonlinear SEMs have demonstrated potential advantages for reconstructing images with higher spatiotemporal resolution and reducing peripheral nerve stimulation. In practice, nonlinear SEMs and linear SEMs can be used jointly to further improve the image...

  16. Different distribution of fluorinated anesthetics and nonanesthetics in model membrane: a 19F NMR study.

    OpenAIRE

    P. Tang; Yan, B.; Xu, Y

    1997-01-01

    Despite their structural resemblance, a pair of cyclic halogenated compounds, 1-chloro-1,2,2-trifluorocyclobutane (F3) and 1,2-dichlorohexafluorocyclobutane (F6), exhibit completely different anesthetic properties. Whereas the former is a potent general anesthetic, the latter produces no anesthesia. Two linear compounds, isoflurane and 2,3-dichlorooctofluorobutane (F8), although not a structural pair, also show the same anesthetic discrepancy. Using 19F nuclear magnetic spectroscopy, we inves...

  17. Magnetic Resonance Imaging in Biomedical Engineering

    Science.gov (United States)

    Kaśpar, Jan; Hána, Karel; Smrčka, Pavel; Brada, Jiří; Beneš, Jiří; Šunka, Pavel

    2007-11-01

    The basic principles of magnetic resonance imaging covering physical principles and basic imaging techniques will be presented as a strong tool in biomedical engineering. Several applications of MRI in biomedical research practiced at the MRI laboratory of the FBMI CTU including other laboratory instruments and activities are introduced.

  18. Interactive Real-time Magnetic Resonance Imaging

    DEFF Research Database (Denmark)

    Brix, Lau

    Real-time acquisition, reconstruction and interactively changing the slice position using magnetic resonance imaging (MRI) have been possible for years. However, the current clinical use of interactive real-time MRI is limited due to an inherent low spatial and temporal resolution. This PhD proje...

  19. Intralabyrinthine schwannoma shown by magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Saeed, S.R. (Univ. Dept. of Otolaryngology, Manchester Royal Infirmary (United Kingdom)); Birzgalis, A.R. (Univ. Dept. of Otolaryngology, Manchester Royal Infirmary (United Kingdom)); Ramsden, R.T. (Univ. Dept. of Otolaryngology, Manchester Royal Infirmary (United Kingdom))

    1994-01-01

    Intralabyrinthine schwannomas are rare benign tumours which present with progressive or fluctuant audiovestibular symptoms and may mimic Menieres disease. The size and position of these lesions make preoperative diagnosis unusual and most are discovered incidentally at labyrinthectomy. A case is reported which was diagnosed on magnetic resonance imaging and confirmed at surgery. (orig.)

  20. Breast magnetic resonance imaging guided biopsy

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Bo La; Kim, Sun Mi; Jang, Mi Jung [Dept. of Radiology, Seoul National University Bundang Hospital, Seongnam (Korea, Republic of); Cho, Nariya; Moon, Woo Kyung [Dept. of Radiology, Seoul National University Hospital, Seoul (Korea, Republic of); Kim, Hak Hee [Dept. of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    2016-06-15

    Despite the high sensitivity of breast magnetic resonance imaging (MRI), pathologic confirmation by biopsy is essential because of limited specificity. MRI-guided biopsy is required in patients with lesions only seen on MRI. We review preprocedural considerations and the technique of MRI-guided biopsy, challenging situations and trouble-shooting, and correlation of radiologic and pathologic findings.

  1. Sports health magnetic resonance imaging challenge.

    Science.gov (United States)

    Howell, Gary A; Stadnick, Michael E; Awh, Mark H

    2010-11-01

    Injuries to the Lisfranc ligament complex are often suspected, particularly in the setting of midfoot pain without radiographic abnormality. Knowledge of the anatomy and magnetic resonance imaging findings of injuries to this region is helpful for the diagnosing and treating physicians.

  2. Evaluation of nuclear magnetic resonance spectroscopy variability

    Energy Technology Data Exchange (ETDEWEB)

    Barreto, Felipe Rodrigues; Salmon, Carlos Ernesto Garrido, E-mail: garrido@ffclrp.usp.br [Universidade de Sao Paulo (FFCLRP/USP), Ribeirao Preto, SP (Brazil). Fac. de Filisofia, Ciencias e Letras; Otaduy, Maria Concepcion Garcia [Universidade de Sao Paulo (FAMUS/USP), Sao Paulo, SP (Brazil). Fac. de Medicina. Departamento de Radiologia

    2014-11-01

    Introduction: the intrinsically high sensitivity of Magnetic Resonance Spectroscopy (MRS) causes considerable variability in metabolite quantification. In this study, we evaluated the variability of MRS in two research centers using the same model of magnetic resonance image scanner. Methods: two metabolic phantoms were created to simulate magnetic resonance spectra from in vivo hippocampus. The phantoms were filled with the same basic solution containing the following metabolites: N-acetyl-aspartate, creatine, choline, glutamate, glutamine and inositol. Spectra were acquired over 15 months on 26 acquisition dates, resulting in a total of 130 spectra per center. Results: the phantoms did not undergo any physical changes during the 15-month period. Temporal analysis from both centers showed mean metabolic variations of 3.7% in acquisitions on the same day and of 8.7% over the 15-month period. Conclusion: The low deviations demonstrated here, combined with the high specificity of Magnetic Resonance Spectroscopy, confirm that it is feasible to use this technique in multicenter studies in neuroscience research. (author)

  3. Brain Morphometry Using Anatomical Magnetic Resonance Imaging

    Science.gov (United States)

    Bansal, Ravi; Gerber, Andrew J.; Peterson, Bradley S.

    2008-01-01

    The efficacy of anatomical magnetic resonance imaging (MRI) in studying the morphological features of various regions of the brain is described, also providing the steps used in the processing and studying of the images. The ability to correlate these features with several clinical and psychological measures can help in using anatomical MRI to…

  4. Use of Magnetic Resonance in Pancreaticobiliary Emergencies.

    Science.gov (United States)

    Bates, David D B; LeBedis, Christina A; Soto, Jorge A; Gupta, Avneesh

    2016-05-01

    This article presents the magnetic resonance protocols, imaging features, diagnostic criteria, and complications of commonly encountered emergencies in pancreaticobiliary imaging. Pancreatic trauma, bile leak, acute cholecystitis, biliary obstruction, and pancreatitis are discussed. Various classifications and complications that can arise with these conditions, as well as artifacts that may mimic pathology, are also included. PMID:27150328

  5. Magnetic resonance imaging in acute tendon ruptures

    Energy Technology Data Exchange (ETDEWEB)

    Daffner, R.H.; Lupetin, A.R.; Dash, N.; Riemer, B.L.

    1986-11-01

    The diagnosis of acute tendon ruptures of the extensor mechanism of the knee or the Achilles tendon of the ankle may usually be made by clinical means. Massive soft tissue swelling accompanying these injuries often obscures the findings, however. Magnetic resonance imaging (MRI) can rapidly demonstrate these tendon ruptures. Examples of the use of MRI for quadriceps tendon, and Achilles tendon rupture are presented.

  6. Nuclear Magnetic Resonance Technology for Medical Studies.

    Science.gov (United States)

    Budinger, Thomas F.; Lauterbur, Paul C.

    1984-01-01

    Reports on the status of nuclear magnetic resonance (NMR) from theoretical and clinical perspectives, reviewing NMR theory and relaxation parameters relevant to NMR imaging. Also reviews literature related to modern imaging strategies, signal-to-noise ratio, contrast agents, in vivo spectroscopy, spectroscopic imaging, clinical applications, and…

  7. Magnetic Resonance Lithography with Nanometer Resolution

    Directory of Open Access Journals (Sweden)

    Fahad AlGhannam

    2016-04-01

    Full Text Available We propose an approach for super-resolution optical lithography which is based on the inverse of magnetic resonance imaging (MRI. The technique uses atomic coherence in an ensemble of spin systems whose final state population can be optically detected. In principle, our method is capable of producing arbitrary one and two dimensional high-resolution patterns with high contrast.

  8. Evaluation of nuclear magnetic resonance spectroscopy variability

    International Nuclear Information System (INIS)

    Introduction: the intrinsically high sensitivity of Magnetic Resonance Spectroscopy (MRS) causes considerable variability in metabolite quantification. In this study, we evaluated the variability of MRS in two research centers using the same model of magnetic resonance image scanner. Methods: two metabolic phantoms were created to simulate magnetic resonance spectra from in vivo hippocampus. The phantoms were filled with the same basic solution containing the following metabolites: N-acetyl-aspartate, creatine, choline, glutamate, glutamine and inositol. Spectra were acquired over 15 months on 26 acquisition dates, resulting in a total of 130 spectra per center. Results: the phantoms did not undergo any physical changes during the 15-month period. Temporal analysis from both centers showed mean metabolic variations of 3.7% in acquisitions on the same day and of 8.7% over the 15-month period. Conclusion: The low deviations demonstrated here, combined with the high specificity of Magnetic Resonance Spectroscopy, confirm that it is feasible to use this technique in multicenter studies in neuroscience research. (author)

  9. Magnetic resonance imaging in radiotherapy treatment planning

    NARCIS (Netherlands)

    Moerland, Marinus Adriaan

    2001-01-01

    From its inception in the early 1970's up to the present, magnetic resonance imaging (MRI) has evolved into a sophisticated technique, which has aroused considerable interest in var- ious subelds of medicine including radiotherapy. MRI is capable of imaging in any plane and does not use ionizing rad

  10. Numerical methods in electron magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Soernes, A.R

    1998-07-01

    The focal point of the thesis is the development and use of numerical methods in the analysis, simulation and interpretation of Electron Magnetic Resonance experiments on free radicals in solids to uncover the structure, the dynamics and the environment of the system.

  11. Imaging Intelligence with Proton Magnetic Resonance Spectroscopy

    Science.gov (United States)

    Jung, Rex E.; Gasparovic, Charles; Chavez, Robert S.; Caprihan, Arvind; Barrow, Ranee; Yeo, Ronald A.

    2009-01-01

    Proton magnetic resonance spectroscopy ([to the first power]H-MRS) is a technique for the assay of brain neurochemistry "in vivo." N-acetylaspartate (NAA), the most prominent metabolite visible within the [to the first power]H-MRS spectrum, is found primarily within neurons. The current study was designed to further elucidate NAA-cognition…

  12. Cardiovascular magnetic resonance in systemic hypertension

    OpenAIRE

    Maceira Alicia M; Mohiaddin Raad H

    2012-01-01

    Abstract Systemic hypertension is a highly prevalent potentially modifiable cardiovascular risk factor. Imaging plays an important role in the diagnosis of underlying causes for hypertension, in assessing cardiovascular complications of hypertension, and in understanding the pathophysiology of the disease process. Cardiovascular magnetic resonance (CMR) provides accurate and reproducible measures of ventricular volumes, mass, function and haemodynamics as well as uniquely allowing tissue char...

  13. Interaction of magnetic resonators studied by the magnetic field enhancement

    Science.gov (United States)

    Hou, Yumin

    2013-12-01

    It is the first time that the magnetic field enhancement (MFE) is used to study the interaction of magnetic resonators (MRs), which is more sensitive than previous parameters-shift and damping of resonance frequency. To avoid the coherence of lattice and the effect of Bloch wave, the interaction is simulated between two MRs with same primary phase when the distance is changed in the range of several resonance wavelengths, which is also compared with periodic structure. The calculated MFE oscillating and decaying with distance with the period equal to resonance wavelength directly shows the retardation effect. Simulation also shows that the interaction at normal incidence is sensitive to the phase correlation which is related with retardation effect and is ultra-long-distance interaction when the two MRs are strongly localized. When the distance is very short, the amplitude of magnetic resonance is oppressed by the strong interaction and thus the MFE can be much lower than that of single MR. This study provides the design rules of metamaterials for engineering resonant properties of MRs.

  14. Interaction of magnetic resonators studied by the magnetic field enhancement

    Directory of Open Access Journals (Sweden)

    Yumin Hou

    2013-12-01

    Full Text Available It is the first time that the magnetic field enhancement (MFE is used to study the interaction of magnetic resonators (MRs, which is more sensitive than previous parameters–shift and damping of resonance frequency. To avoid the coherence of lattice and the effect of Bloch wave, the interaction is simulated between two MRs with same primary phase when the distance is changed in the range of several resonance wavelengths, which is also compared with periodic structure. The calculated MFE oscillating and decaying with distance with the period equal to resonance wavelength directly shows the retardation effect. Simulation also shows that the interaction at normal incidence is sensitive to the phase correlation which is related with retardation effect and is ultra-long-distance interaction when the two MRs are strongly localized. When the distance is very short, the amplitude of magnetic resonance is oppressed by the strong interaction and thus the MFE can be much lower than that of single MR. This study provides the design rules of metamaterials for engineering resonant properties of MRs.

  15. Interaction of magnetic resonators studied by the magnetic field enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Yumin, E-mail: ymhou@pku.edu.cn [State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China)

    2013-12-15

    It is the first time that the magnetic field enhancement (MFE) is used to study the interaction of magnetic resonators (MRs), which is more sensitive than previous parameters–shift and damping of resonance frequency. To avoid the coherence of lattice and the effect of Bloch wave, the interaction is simulated between two MRs with same primary phase when the distance is changed in the range of several resonance wavelengths, which is also compared with periodic structure. The calculated MFE oscillating and decaying with distance with the period equal to resonance wavelength directly shows the retardation effect. Simulation also shows that the interaction at normal incidence is sensitive to the phase correlation which is related with retardation effect and is ultra-long-distance interaction when the two MRs are strongly localized. When the distance is very short, the amplitude of magnetic resonance is oppressed by the strong interaction and thus the MFE can be much lower than that of single MR. This study provides the design rules of metamaterials for engineering resonant properties of MRs.

  16. Magnetic resonance imaging of infectious myositis

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Ji Young; Kim, Jee Young; Kim, Sang Heum; Jung, Youn Ju; Cha, Eun Suk; Park, Joung Mi; Park, Young Ha [The Catholic Univ., College of Medicine, Suwon (Korea, Republic of)

    1998-09-01

    To describe the findings of magnetic resonance imaging in infectious myositis and to determine their value for differentiation between ruberculous and bacterial myositis. Magnetic resonance images of ten proven cases of infectious myositis (five tuberculous and five bacterial) were retrospectively reviewed in the light of clinical and laboratory findings. On the basis of magnetic resonance images, signal intensity of the mass, the presence or absence of an abscess, signal intensity of the peripheral wall, patterns of contrast enhancement, and associated findings were evaluated. Compared with those of bacterial myositis, the symptoms of tuberculous myositis lasted longer but there were no difinite local inflammatory signs. In three of five cases of bacterial myositis there were specific medical records;trauma in two cases and systemic lupus erythematosus in one. All tuberculous myositis cases involved a single muscle, but bacterial myositis affected multipe muscles in three cases(60%). All but one case showed a mass in the involved muscles. In one bacterial case, there was diffuse swelling in the involved muscle. On T1-weighted images, eight infectious cases showed low signal intensity;two, of the bactrerial type, showed subtle increased signal intensity. all cases demonstrated high signal intensity on t2-weighted images. The signal intensity of peripheral wall was slightly increased on T1-weighted images, but low on T2-weighted. In four cases there was associated cellulitis, and in one case each, adjacent joint effusion and deep vein thrombosis were seen. After gadolinium infusion, peripheral rim enhancement was noted in nine cases and heterogeneous enhancement in one. After magnetic resonance imaging of infectious myositis, the characteristic finding was an abscessed lesion, with the peripheral wall showing high signal intensity on T1-weighted images and low signal intensity on T2 weighted. Although we found it difficult to differentiate bacterial from tuberculous

  17. The working principle of magnetic resonance therapy

    CERN Document Server

    Brizhik, Larissa; Fermi, Enrico

    2015-01-01

    In this paper we describe briefly the basic aspects of magnetic resonance therapy, registered as TMR therapy. Clinical studies have shown that application of this therapy significantly accelerates wound healing and, in particular, healing of the diabetic foot disease. To understand the working principle of this therapy, we analyze relevant to it biological effects produced by magnetic fields. Based on these data, we show that there is a hierarchy of the possible physical mechanisms, which can produce such effects. The mutual interplay between the mechanisms can lead to a synergetic outcome delayed in time, which can affect the physiological state of the organism. In particular, we show that soliton mediated charge transport during the redox processes in living organisms is sensitive to magnetic fields, so that such fields can facilitate redox processes in particular, and can stimulate the healing effect of the organism in general. This and other non-thermal resonant mechanisms of the biological effects of mag...

  18. Nuclear magnetic resonance properties of lunar samples.

    Science.gov (United States)

    Kline, D.; Weeks, R. A.

    1972-01-01

    Nuclear magnetic resonance spectra of Na-23, Al-27, and P-31 in fines samples 10084,60 and 14163,168 and in crystalline rock samples 12021,55 and 14321,166, have been recorded over a range of frequencies up to 20 MHz. A shift in the field at which maximum absorption occurs for all of the spectra relative to the field at which maximum absorption occurs for terrestrial analogues is attributed to a sample-dependent magnetic field at the Na, Al, and P sites opposing the laboratory field. The magnitude of these fields internal to the samples is sample dependent and varies from 5 to 10 G. These fields do not correlate with the iron content of the samples. However, the presence of single-domain particles of iron distributed throughout the plagioclase fraction that contains the principal fraction of Na and Al is inferred from electron magnetic resonance spectra shapes.

  19. Magnetic Earth Ionosphere Resonant Frequencies

    Science.gov (United States)

    Spaniol, Craig

    1994-01-01

    The Community College Division is pleased to report progress of NASA funded research at West Virginia State College. During this reporting period, the project research group has continued with activities to develop instrumentation capability designed to monitor resonant cavity frequencies in the atmospheric region between the Earth's surface and the ionosphere. In addition, the project's principal investigator, Dr. Craig Spaniol, and NASA technical officer, Dr. John Sutton, have written and published technical papers intended to expand the scientific and technical framework needed for project research. This research continues to provide an excellent example of government and education working together to provide significant research in the college environment. This cooperative effort has provided many students with technical project work which compliments their education.

  20. {sup 19}F MRI oximetry: simulation of perfluorocarbon distribution impact

    Energy Technology Data Exchange (ETDEWEB)

    Baete, S H; Vandecasteele, J; De Deene, Y, E-mail: steven.baete@ugent.be [Department of Radiation Oncology and Experimental Cancer Research, Ghent University, De Pintelaan 185, 9000 Gent (Belgium)

    2011-04-21

    In {sup 19}F MRI oximetry, a method used to image tumour hypoxia, perfluorocarbons serve as oxygenation markers. The goal of this study is to evaluate the impact of perfluorocarbon distribution and concentration in {sup 19}F MRI oximetry through a computer simulation. The simulation studies the correspondence between {sup 19}F measured (pO{sup FNMR}{sub 2}) and actual tissue oxygen tension (pO{sub 2}) for several tissue perfluorocarbon distributions. For this, a Krogh tissue model is implemented which incorporates the presence of perfluorocarbons in blood and tissue. That is, in tissue the perfluorocarbons are distributed homogeneously according to Gaussian diffusion profiles, or the perfluorocarbons are concentrated in the capillary wall. Using these distributions, the oxygen tension in the simulation volume is calculated. The simulated mean oxygen tension is then compared with pO{sup FNMR}{sub 2}, the {sup 19}F MRI-based measure of pO{sub 2} and with pO{sup 0}{sub 2}, pO{sub 2} in the absence of perfluorocarbons. The agreement between pO{sup FNMR}{sub 2} and actual pO{sub 2} is influenced by vascular density and perfluorocarbon distribution. The presence of perfluorocarbons generally gives rise to a pO{sub 2} increase in tissue. This effect is enhanced when perfluorocarbons are also present in blood. Only the homogeneous perfluorocarbon distribution in tissue with no perfluorocarbons in blood guarantees small deviations of pO{sup FNMR}{sub 2} from pO{sub 2}. Hence, perfluorocarbon distribution in tissue and blood has a serious impact on the reliability of {sup 19}F MRI-based measures of oxygen tension. In addition, the presence of perfluorocarbons influences the actual oxygen tension. This finding may be of great importance for further development of {sup 19}F MRI oximetry.

  1. Magnetic resonance imaging by using nano-magnetic particles

    Energy Technology Data Exchange (ETDEWEB)

    Shokrollahi, H., E-mail: Shokrollahi@sutech.ac.ir [Electroceramics Group, Department of Materials Science and Engineering, Shiraz University of Technology, Shiraz (Iran, Islamic Republic of); Khorramdin, A. [Electroceramics Group, Department of Materials Science and Engineering, Shiraz University of Technology, Shiraz (Iran, Islamic Republic of); Isapour, Gh. [Department of Materials and Engineering, Hakim Sabzevari University (Iran, Islamic Republic of)

    2014-11-15

    Magnetism and magnetic materials play a major role in various biological applications, such as magnetic bioseparation, magnetic resonance imaging (MRI), hyperthermia treatment of cancer and drug delivery. Among these techniques, MRI is a powerful method not only for diagnostic radiology but also for therapeutic medicine that utilizes a magnetic field and radio waves. Recently, this technique has contributed greatly to the promotion of the human quality life. Thus, this paper presents a short review of the physical principles and recent advances of MRI, as well as providing a summary of the synthesis methods and properties of contrast agents, like different core materials and surfactants. - Highlights: • This paper studies the physics of MRI as a powerful diagnostic technique. • MRI uses the differentiation between healthy and pathological tissues. • The relaxation times can be shortened by the use of a magnetic contrast agent. • The magnetic nanoparticles act as contrast agents, helping to increase the resolution. • Different synthesis methods can influence the magnetic resonance behavior.

  2. Nuclear magnetic resonance (NMR): principles and applications

    International Nuclear Information System (INIS)

    The basis for the phenomenon of nuclear magnetic resonance (NMR) is the ability of certain nuclei possessing both intrinsic angular momentum or ''spin'' I and magnetic moment to absorb electromagnetic energy in the radio frequency range. In principle, there are approximately 200 nuclei which may be investigated using the NMR technique. The NMR spectrum consists of intensity peaks along an axis calibrated in terms of the steady magnetic field or the frequency of the radiofrequency electromagnetic radiation. Analysis of the number, spacing, position and intensity of the lines in an NMR spectrum consists of intensity peaks along an axis calibrated in terms of the steady magnetic field or the frequency of the radiofrequency electromagnetic radiation. Analysis of the number, spacing, position and intensity of the lines in an NMR spectrum provides a variety of qualitative and quantitative analytical applications. The most obvious applications consist of the measurements of nuclear properties, such as spin number and nuclear magnetic moment. In liquids, the fine structure of resonance spectra provides a tool for chemical identification and molecular structure analysis. Other applications include the measurements of self-diffusion coefficients, magnetic fields and field homogeneity, inter-nuclear distances, and, in some cases, the water content of biological materials. (author)

  3. 21 CFR 892.1000 - Magnetic resonance diagnostic device.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Magnetic resonance diagnostic device. 892.1000... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1000 Magnetic resonance diagnostic device. (a) Identification. A magnetic resonance diagnostic device is intended for general diagnostic...

  4. Advances in magnetic and optical resonance

    CERN Document Server

    Warren, Warren S

    2013-01-01

    Advances in Magnetic and Optical Resonance contains three articles which review quite fundamentally different aspects of coherent spectroscopy. An enormous variety of effects can be observed when optical and spin resonances are coupled, usually by a combination of radio frequency and laser irradiation. The first article reviews these effects and pays particular attention to developing a theoretical framework which is as similar as possible for the optical and spin cases. Subsequent articles examine deuterium relaxation in molecular solids, and the spatiotemporal growth of multiple spin coheren

  5. A hyperpolarized equilibrium for magnetic resonance

    Science.gov (United States)

    Hövener, Jan-Bernd; Schwaderlapp, Niels; Lickert, Thomas; Duckett, Simon B.; Mewis, Ryan E.; Highton, Louise A. R.; Kenny, Stephen M.; Green, Gary G. R.; Leibfritz, Dieter; Korvink, Jan G.; Hennig, Jürgen; von Elverfeldt, Dominik

    2013-12-01

    Nuclear magnetic resonance spectroscopy and imaging (MRI) play an indispensable role in science and healthcare but use only a tiny fraction of their potential. No more than ≈10 p.p.m. of all 1H nuclei are effectively detected in a 3-Tesla clinical MRI system. Thus, a vast array of new applications lays dormant, awaiting improved sensitivity. Here we demonstrate the continuous polarization of small molecules in solution to a level that cannot be achieved in a viable magnet. The magnetization does not decay and is effectively reinitialized within seconds after being measured. This effect depends on the long-lived, entangled spin-order of parahydrogen and an exchange reaction in a low magnetic field of 10-3 Tesla. We demonstrate the potential of this method by fast MRI and envision the catalysis of new applications such as cancer screening or indeed low-field MRI for routine use and remote application.

  6. Synthesis of 19F in Wolf-Rayet stars

    Science.gov (United States)

    Meynet, G.; Arnould, M.

    2000-03-01

    Meynet & Arnould (1993) have suggested that Wolf-Rayet (WR) stars could significantly contaminate the Galaxy with \\chem{19}{F}. In their scenario, \\chem{19}{F} is synthesized at the beginning of the He-burning phase from the \\chem{14}{N} left over by the previous CNO-burning core, and is ejected in the interstellar medium when the star enters its WC phase. Recourse to CNO seeds makes the \\chem{19}{F} yields metallicity-dependent. These yields are calculated on grounds of detailed stellar evolutionary sequences for an extended range of initial masses (from 25 to 120 Msun) and metallicities (Z=0.008, 0.02 and 0.04). The adopted mass loss rate prescription enables to account for the observed variations of WR populations in different environments. The \\chem{19}{F} abundance in the WR winds of 60 M_sun model stars is found to be about 10 to 70 times higher than its initial value, depending on the metallicity. This prediction is used in conjunction with a very simple model for the chemical evolution of the Galaxy to predict that WR stars could be significant (dominant?) contributors to the solar system fluorine content. We also briefly discuss the implications of our model on the possible detection of fluorine at high redshift.

  7. Synthesis of $^{19}F$ in Wolf-Rayet stars

    CERN Document Server

    Meynet, G

    2000-01-01

    Meynet and Arnould (1993) have suggested that Wolf-Rayet (WR) stars could significantly contaminate the Galaxy with 19F. In their scenario, 19F is synthesized at the beginning of the He-burning phase from the 14N left over by the previous CNO-burning core, and is ejected in the interstellar medium when the star enters its WC phase. Recourse to CNO seeds makes the 19F yields metallicity-dependent. These yields are calculated on grounds of detailed stellar evolutionary sequences for an extended range of initial masses (from 25 to 120 Msol) and metallicities (Z = 0.008, 0.02 and 0.04). The adopted mass loss rate prescription enables to account for the observed variations of WR populations in different environments. The 19F abundance in the WR winds of 60 Msol model stars is found to be about 10 to 70 times higher than its initial value, depending on the metallicity. This prediction is used in conjunction with a very simple model for the chemical evolution of the Galaxy to predict that WR stars could be significa...

  8. Thin layer and nuclear magnetic resonance magnetometers

    International Nuclear Information System (INIS)

    In the first part of this text, magnetometers with sensitive elements in the form of thin cylindrical ferromagnetic layers are described. These layers are anisotropic, uniaxial, C orientated and single domains. In the second part of the text, the principles of the nuclear magnetic resonance magnetometer realized at the LETI are presented. This instrument is accurate, of high efficiency, and isotropic. Very small variations in magnetic field intensity (10-7 oersteds) can be detected with a 1Hz pass band at zero frequency

  9. Magnetic resonance semiotics of breast fibroadenomas

    Directory of Open Access Journals (Sweden)

    S. V. Serebryakova

    2010-01-01

    Full Text Available Various benign breast abnormalities are diagnosed in 60% of women in Russia today. This is associated with failure of preoperative recognition of the histological class of an identified nodular mass – its detection is an indication for surgical treatment. By using 67 histologically verified breast fibroadenomas (FA as an example, the authors describe their magnetic resonance semiotics and present the differential diagnostic criteria used during dynamic contrast-enhanced magnetic resonance mammography. FAs are characterized by well-defined uniform outlines, homogeneous internal structure, centrifugal and homogeneous accumulation of contrast media through- out the study, without deforming the breast vasculature around. One of the criteria that permit differential diagnosis of FA with malignan- cies is their estimated vascularization.

  10. Sensorineural hearing loss after magnetic resonance imaging

    DEFF Research Database (Denmark)

    Mollasadeghi, Abolfazl; Mehrparvar, Amir Houshang; Atighechi, Saeid;

    2013-01-01

    Magnetic resonance imaging (MRI) devices produce noise, which may affect patient's or operators' hearing. Some cases of hearing impairment after MRI procedure have been reported with different patterns (temporary or permanent, unilateral or bilateral, with or without other symptoms like tinnitus)......). In this report, a case of bilateral sensorineural hearing loss in an otherwise healthy patient underwent brain MRI was described. The patient's hearing loss was accompanied with tinnitus and was not improved after 3 months of followup.......Magnetic resonance imaging (MRI) devices produce noise, which may affect patient's or operators' hearing. Some cases of hearing impairment after MRI procedure have been reported with different patterns (temporary or permanent, unilateral or bilateral, with or without other symptoms like tinnitus...

  11. Contribution of magnetic resonance imaging in rheumatology

    Energy Technology Data Exchange (ETDEWEB)

    Lavieille, J.; Amalric, R.; Stanoyevitch, J.F.; Hopf, M.A.; Antipoff, G.M.; Roux, H.

    1986-11-01

    The authors report their experience with magnetic resonance imaging in rheumatology, established on more than 250 examinations. The method seems interesting for the study of discal and somatic spine diseases, and especially for the evaluation of tumor extension, the diagnosis of herniated disc, the diagnosis of spondylodiscitis, the exploration of the cervico-occipital joint. As compared to tomodensitometry, this method presents at the same time advantages and drawbacks. Peripherally, magnetic resonance imaging is useful for the exploration of bony tumors and evaluation of their extension. It gives excellent images of the knees and the hips where it seems to improve the results of tomodensitometry and bony scintigraphy in the diagnosis of osteonecrosis. It is likely that advances will broaden the scope of the indications and capabilities of this method.

  12. Magnetic resonance imaging findings in tuberculous meningoencephalitis

    Energy Technology Data Exchange (ETDEWEB)

    Pui, M.H.; Memon, W.A. [Aga Khan Univ. Hospital, Dept. of Radiology, Karachi (Pakistan)

    2001-02-01

    To evaluate the efficacy of magnetic resonance imaging (MRI) for distinguishing tuberculosis from other types of meningoencephalitis. MRIs of 100 patients with tuberculous (50), pyogenic (33), viral (14), or fungal (3) meningoencephalitis were analyzed independently by 2 radiologists. Number, size, location, signal characteristics, surrounding edema, and contrast enhancement pattern of nodular lesions; location and pattern of meningeal enhancement; extent of infarct or encephalitis and hydrocephalus were evaluated. Contrast-enhancing nodular lesions were detected in patients with tuberculous (43 of 50 patients), pyogenic (9 of 33), and fungal (3 of 3) infections. No nodules were detected in patients with viral meningoencephalitis. Using the criteria of 1 or more solid rim or homogeneously enhancing nodules smaller than 2 cm, the sensitivity, specificity and accuracy for diagnosing tuberculous meningitis were 86.0%, 90.0% and 88.0%, respectively. Magnetic resonance imaging is useful in distinguishing tuberculous from pyogenic, viral and fungal meningoencephalitis. (author)

  13. Measurement of myocardial perfusion using magnetic resonance

    DEFF Research Database (Denmark)

    Fritz-Hansen, T.; Jensen, L.T.; Larsson, H.B.;

    2008-01-01

    Cardiac magnetic resonance imaging (MRI) has evolved rapidly. Recent developments have made non-invasive quantitative myocardial perfusion measurements possible. MRI is particularly attractive due to its high spatial resolution and because it does not involve ionising radiation. This paper review...... myocardial perfusion imaging with MR contrast agents: methods, validation and experiences from clinical studies. Unresolved issues still restrict the use of these techniques to research although clinical applications are within reach Udgivelsesdato: 2008/12/8......Cardiac magnetic resonance imaging (MRI) has evolved rapidly. Recent developments have made non-invasive quantitative myocardial perfusion measurements possible. MRI is particularly attractive due to its high spatial resolution and because it does not involve ionising radiation. This paper reviews...

  14. High speed functional magnetic resonance imaging

    CERN Document Server

    Gibson, A M

    2002-01-01

    The work in this thesis has been undertaken by the except where indicated by reference, within the Magnetic Resonance Centre at the University of Nottingham during the period from October 1998 to October 2001. This thesis documents the implementation and application of a novel high-speed imaging technique, the multi-slice, echo shifted, echo planar imaging technique. This was implemented on the Nottingham 3 T imaging system, for functional magnetic resonance imaging. The technique uses echo shifting over the slices in a multi-slice echo planar imaging acquisition scheme, making the echo time longer than the repetition time per slice. This allows for rapid volumar sampling of the blood oxygen level dependent effect in the human brain. The new high-speed technique was used to investigate the variability of measuring the timing differences between haemodynamic responses, at the same cortical location, to simple cued motor tasks. The technique was also used in an investigation into motor cortex functional connect...

  15. Female pelvic anatomy: magnetic resonance study

    International Nuclear Information System (INIS)

    The potential of magnetic resonance imaging was evaluated in this study. Conventional imaging methods like sonography and X-ray computerised tomography generally provide accurate data. Magnetic resonance imaging appears to be very suitable for studying the pelvis because it has the capacity to produce direct multidirectional images. By recording alterations in T1 and T2 values, it provides a wide range of information. A 1.5 T imaging system was used. Pulse sequences used always included T1 and T2 weighted spin-echo scans. The T2 scan was performed in the best plane for the organ of interest. The comparison between these different acquisitions provides good tissue differentiation. Results of 73 studies are exposed

  16. Intracellular pH of perfused single frog skin: combined 19F- and 31P-NMR analysis.

    Science.gov (United States)

    Civan, M M; Lin, L E; Peterson-Yantorno, K; Taylor, J; Deutsch, C

    1984-11-01

    Intracellular pH (pHc) has been determined in frog skin by applying two different methods of pH measurement, 19F and 31P nuclear magnetic resonance (NMR) analysis, to the same tissues. Results from both NMR approaches confirm an observation by Lin, Shporer, and Civan [Am. J. Physiol. 248 (Cell Physiol. 17): 1985] that acidification of the extracellular medium reverses the sign of the pH gradient present under baseline conditions. The fluorinated probe, alpha-(difluoromethyl)-alanine methyl ester, was introduced into the epithelial cells by preincubating skins for 4.7-10.4 h at room temperature in Ringer solutions containing 1 mM ester. The free amino acid was subsequently released by intracellular esterase activity, thus providing a high enough probe concentration for NMR analysis to be practicable. From measurements of short-circuit current and transepithelial resistance under base-line and experimental conditions and the appearance of phosphocreatine (PCr) in the 31P spectrum of preloaded tissues, the fluorinated probe appears to be nontoxic to frog skin. Measurement of the chemical shift of methylphosphonate relative to PCr permitted calculation of extracellular pH. Estimation of the intracellular pH was performed both by measurement of the chemical shift of inorganic phosphate (Pi) relative to PCr and by measurement of the central peak spacing of the 19F spectrum. From four direct comparisons of the two techniques in two experiments, the difference in the estimated pH was only 0.03 +/- 0.07 pH units, supporting the concept that 31P-NMR analysis is a valid method of measuring pH in this tissue. PMID:6496729

  17. Magnetic resonance imaging for acute pancreatitis

    OpenAIRE

    Xiao, Bo; Zhang, Xiao-Ming

    2010-01-01

    Acute pancreatitis is characterized by acute chemical injury of the pancreatic parenchyma and peripancreatic tissue. The increased frequency of death in acute pancreatitis is directly correlated with the degree and progress of pancreatic necrosis. Moreover, the occurrence of some local complications in acute pancreatitis, such as pancreatic hemorrhage, peripancreatic abscess or large pseudocyst, and pseudoaneurysm, could influence the choice of treatment for these patients. Magnetic resonance...

  18. Perfusion magnetic resonance imaging of the liver

    Institute of Scientific and Technical Information of China (English)

    Choon; Hua; Thng; Tong; San; Koh; David; J; Collins; Dow; Mu; Koh

    2010-01-01

    Perfusion magnetic resonance imaging (MRI) studies quantify the microcirculatory status of liver parenchyma and liver lesions, and can be used for the detection of liver metastases, assessing the effectiveness of antiangiogenic therapy, evaluating tumor viability after anticancer therapy or ablation, and diagnosis of liver cirrhosis and its severity. In this review, we discuss the basic concepts of perfusion MRI using tracer kinetic modeling, the common kinetic models applied for analyses, the MR scanning t...

  19. "PALPATION BY IMAGING": MAGNETIC RESONANCE ELASTOGRAPHY

    Institute of Scientific and Technical Information of China (English)

    Lei Xu; Pei-yi Gao

    2006-01-01

    Elasticity is an important physical property of human tissues.There is a tremendous difference in elasticity between normal and pathological tissues.Noninvasive evaluation of the elasticity of human tissues would be valuable for clinical practice.Magnetic resonance elastography(MRE)is a recently developed noninvasive imaging technique that can directly visualize and quantitatively measure tissue elasticity.This article reviewed the MRE technique and its current status.

  20. Magnetic Resonance Elastography: Inversions in Bounded Media

    OpenAIRE

    Kolipaka, Arunark; McGee, Kiaran P.; Manduca, Armando; Romano, Anthony J; Glaser, Kevin J.; Araoz, Philip A; Ehman, Richard L.

    2009-01-01

    Magnetic resonance elastography (MRE) is a noninvasive imaging technique capable of quantifying and spatially resolving the shear stiffness of soft tissues by visualization of synchronized mechanical wave displacement fields. However, MRE inversions generally assume that the measured tissue motion consists primarily of shear waves propagating in a uniform, infinite medium. This assumption is not valid in organs such as the heart, eye, bladder, skin, fascia, bone and spinal cord in which the s...

  1. Magnetic resonance imaging of pancreatitis: An update

    OpenAIRE

    Manikkavasakar, Sriluxayini; AlObaidy, Mamdoh; Busireddy, Kiran K; Ramalho, Miguel; Nilmini, Viragi; Alagiyawanna, Madhavi; Semelka, Richard C

    2014-01-01

    Magnetic resonance (MR) imaging plays an important role in the diagnosis and staging of acute and chronic pancreatitis and may represent the best imaging technique in the setting of pancreatitis due to its unmatched soft tissue contrast resolution as well as non-ionizing nature and higher safety profile of intravascular contrast media, making it particularly valuable in radiosensitive populations such as pregnant patients, and patients with recurrent pancreatitis requiring multiple follow-up ...

  2. Cardiovascular magnetic resonance in carotid atherosclerotic disease

    OpenAIRE

    Chen Huijun; Wang Jinnan; Li Rui; Ferguson Marina S; Kerwin William S; Dong Li; Canton Gador; Hatsukami Thomas S; Yuan Chun

    2009-01-01

    Abstract Atherosclerosis is a chronic, progressive, inflammatory disease affecting many vascular beds. Disease progression leads to acute cardiovascular events such as myocardial infarction, stroke and death. The diseased carotid alone is responsible for one third of the 700,000 new or recurrent strokes occurring yearly in the United States. Imaging plays an important role in the management of atherosclerosis, and cardiovascular magnetic resonance (CMR) of the carotid vessel wall is one promi...

  3. Myocardial tissue tagging with cardiovascular magnetic resonance

    OpenAIRE

    Bluemke David A; Osman Nael F; Cheng Susan; Shehata Monda L; Lima João AC

    2009-01-01

    Abstract Cardiovascular magnetic resonance (CMR) is currently the gold standard for assessing both global and regional myocardial function. New tools for quantifying regional function have been recently developed to characterize early myocardial dysfunction in order to improve the identification and management of individuals at risk for heart failure. Of particular interest is CMR myocardial tagging, a non-invasive technique for assessing regional function that provides a detailed and compreh...

  4. Cardiovascular magnetic resonance in pulmonary hypertension

    OpenAIRE

    Bradlow William M; R Gibbs J Simon; Mohiaddin Raad H

    2012-01-01

    Abstract Pulmonary hypertension represents a group of conditions characterized by higher than normal pulmonary artery pressures. Despite improved treatments, outcomes in many instances remain poor. In recent years, there has been growing interest in the use of Cardiovascular Magnetic Resonance (CMR) in patients with pulmonary hypertension. This technique offers certain advantages over other imaging modalities since it is well suited to the assessment of the right ventricle and the proximal pu...

  5. Quantitative cardiovascular magnetic resonance for molecular imaging

    OpenAIRE

    Lanza Gregory M; Caruthers Shelton D; Winter Patrick M; Wickline Samuel A

    2010-01-01

    Abstract Cardiovascular magnetic resonance (CMR) molecular imaging aims to identify and map the expression of important biomarkers on a cellular scale utilizing contrast agents that are specifically targeted to the biochemical signatures of disease and are capable of generating sufficient image contrast. In some cases, the contrast agents may be designed to carry a drug payload or to be sensitive to important physiological factors, such as pH, temperature or oxygenation. In this review, examp...

  6. Functional magnetic resonance imaging in schizophrenia

    OpenAIRE

    Gur, Raquel E.; Gur, Ruben C.

    2010-01-01

    The integration of functional magnetic resonance imaging (fMRI) with cognitive and affective neuroscience paradigms enables examination of the brain systems underlying the behavioral deficits manifested in schizophrenia; there have been a remarkable increase in the number of studies that apply fMRI in neurobiological studies of this disease. This article summarizes features of fMRI methodology and highlights its application in neurobehavioral studies in schizophrenia. Such work has helped elu...

  7. Cardiovascular magnetic resonance imaging - a pictorial review

    OpenAIRE

    Vijay Dahya; Spottiswoode, Bruce S.

    2010-01-01

    Cardiovascular magnetic resonance imaging (CMR) is a powerful problem-solving tool and arguably offers the most comprehensive assessment of cardiac morphology and function, as well as the opportunity of rebuilding the bridge between cardiologists and radiologists. The role of CMR-trained imaging physicists is also valuable, and many CMR centres harmoniously incorporate these three sub-specialty fields. This paper comprises an overview of several CMR techniques, outlining both the strengths...

  8. Cardiovascular magnetic resonance imaging - a pictorial review

    Directory of Open Access Journals (Sweden)

    Vijay Dahya

    2010-12-01

    Full Text Available Cardiovascular magnetic resonance imaging (CMR is a powerful problem-solving tool and arguably offers the most comprehensive assessment of cardiac morphology and function, as well as the opportunity of rebuilding the bridge between cardiologists and radiologists. The role of CMR-trained imaging physicists is also valuable, and many CMR centres harmoniously incorporate these three sub-specialty fields. This paper comprises an overview of several CMR techniques, outlining both the strengths and limitations of the modality.

  9. Novel aspects of brain metabolism as revealed by magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Full text: The techniques of Magnetic Resonance Spectroscopy (MRS) and Imaging (MRI) are outlined, and compared with Positron Emission Tomography (PET). Invasive PET techniques using 19F-fluorodeoxyglucose (FDG) and 18O2 form the main basis of brain activation studies, and with 19F-fluoroDOPA, make major contributions to studies on neurological disorders such as stroke, Alzheimer's disease and Parkinson's disease. However the technique has no chemical specificity so can provide no knowledge of intermediary metabolism. Non-invasive MRI is also being applied to brain activation studies but also has no chemical specificity. On the other hand MRS has superb chemical specificity, although it suffers from low sensitivity. A most interesting example of this is the use of 13C-MRS. If glucose is labelled on the no. 1 or no. 2 positions with 13C, the passage of the label through different neuronal and glial metabolic pathways can be followed. If acetate is similarly labelled, metabolic routes through specifically glial pathways can be monitored, since acetate is taken up only by glia. These studies contributed to knowledge on metabolic trafficking, in that glia produce alanine, citrate and lactate in addition to the previously characterised production of glutamine. Studies on the hypoxic brain revealed increased production of alanine, lactate and glycerol 3-phosphate, providing further understanding of the role of the NADH redox state. 'Isotopomer analysis' of 13C resonances provides more information on metabolic pathways, because the chemical shift of a 13C atom is specifically affected by a neighbouring 13C within the same molecule. This approach was used to demonstrate that neurotransmitter γ-aminobutyrate (GABA) is partly derived from glial glutamine. Analogous 13C MRS studies are now providing novel information on metabolic flux rates within the human brain, and the most exciting developments are to follow changes in these rates on brain activation which can be

  10. Waveguide volume probe for magnetic resonance imaging and spectroscopy

    DEFF Research Database (Denmark)

    2015-01-01

    The present disclosure relates to a probe for use within the field of nuclear magnetic resonance, such as magnetic resonance imaging (MRI), and magnetic resonance spectroscopy (MRS)). One embodiment relates to an RF probe for magnetic resonance imaging and/or spectroscopy comprising a conductive...... non-magnetic hollow waveguide having an internal volume and at least one open end, one or more capacitors and at least a first conductive non-magnetic wire, wherein said first conductive wire connects at least one of said one or more capacitors to opposite walls of one open end of the waveguide...

  11. Electro-Mechanical Resonant Magnetic Field Sensor

    CERN Document Server

    Temnykh, A B; Temnykh, Alexander B.; Lovelace, Richard V. E.

    2002-01-01

    We describe a new type of magnetic field sensor which is termed an Electro-Mechanical Resonant Sensor (EMRS). The key part of this sensor is a small conductive elastic element with low damping rate and therefore a high Q fundamental mode of frequency $f_1$. An AC current is driven through the elastic element which, in the presence of a magnetic field, causes an AC force on the element. When the frequency of the AC current matches the resonant frequency of the element, maximum vibration of the element occurs and this can be measured precisely by optical means. We have built and tested a model sensor of this type using for the elastic element a length of copper wire of diameter 0.030 mm formed into a loop shape. The wire motion was measured using a light emitting diode photo-transistor assembly. This sensor demonstrated a sensitivity better than 0.001G for an applied magnetic field of $ \\sim 1$G and a good selectivity for the magnetic field direction. The sensitivity can be easily improved by a factor of $\\sim ...

  12. Compact low field magnetic resonance imaging magnet: Design and optimization

    Science.gov (United States)

    Sciandrone, M.; Placidi, G.; Testa, L.; Sotgiu, A.

    2000-03-01

    Magnetic resonance imaging (MRI) is performed with a very large instrument that allows the patient to be inserted into a region of uniform magnetic field. The field is generated either by an electromagnet (resistive or superconductive) or by a permanent magnet. Electromagnets are designed as air cored solenoids of cylindrical symmetry, with an inner bore of 80-100 cm in diameter. In clinical analysis of peripheral regions of the body (legs, arms, foot, knee, etc.) it would be better to adopt much less expensive magnets leaving the most expensive instruments to applications that require the insertion of the patient in the magnet (head, thorax, abdomen, etc.). These "dedicated" apparati could be smaller and based on resistive magnets that are manufactured and operated at very low cost, particularly if they utilize an iron yoke to reduce power requirements. In order to obtain good field uniformity without the use of a set of shimming coils, we propose both particular construction of a dedicated magnet, using four independently controlled pairs of coils, and an optimization-based strategy for computing, a posteriori, the optimal current values. The optimization phase could be viewed as a low-cost shimming procedure for obtaining the desired magnetic field configuration. Some experimental measurements, confirming the effectiveness of the proposed approach (construction and optimization), have also been reported. In particular, it has been shown that the adoption of the proposed optimization based strategy has allowed the achievement of good uniformity of the magnetic field in about one fourth of the magnet length and about one half of its bore. On the basis of the good experimental results, the dedicated magnet can be used for MRI of peripheral regions of the body and for animal experimentation at very low cost.

  13. First national meeting of magnetic resonance and hyperfine interactions

    International Nuclear Information System (INIS)

    Works performed at CNEA's: Magnetic Resonance Division; Moessbauer Spectroscopy; Solid State Physics Division; Nuclear magnetic Resonance Laboratory and Theoretical Physics Group; Mossbauer Spectroscopy Group; Nuclear Quadrupole Resonance; Physics and Materials Group; Perturbed Angular Correlation and Moessbauer Spectroscopy and Physics Department. (M.E.L.)

  14. Nuclear magnetic resonance imaging in brain tumors

    International Nuclear Information System (INIS)

    Full text: Magnetic resonance imaging (MRI) is a non-invasive imaging method based on the detecting signal from hydrogen nuclei of water molecules and fat. Performances of MRI are continuously increasing, and its domains of investigation of the human body are growing in both morphological and functional study. MRI also allows It also performing advanced management of tumours especially in the brain, by combining anatomical information (morphological MRI), functional (diffusion, perfusion and BOLD contrast) and metabolic (tissue composition in magnetic resonance spectroscopy (MRS)). The MRI techniques have an important role in cancerology. These techniques allow essential information for the diagnosis and answering therapist's questions before, during or after the treatment. The MR allows clarifying the localization of expanding processes, the differential diagnosis between brain tumour and a lesion confined by another structural aspect, the diagnosis of the tumoral aspect of a lesion, the histological ranking in case of glial tumour and the extension of its localization as well as the therapeutic follow-up (pre-therapeutic and post-therapeutics assessments). A better combination between the morphological, functional and metabolic studies, as well as integrating new technical developments, especially while using a multichannel bird cage coils the 3T magnet and suitable computing software, would allow significant improvements of the exploration strategies and management of brain tumors.

  15. Magnetic resonance imaging of valvular heart disease

    DEFF Research Database (Denmark)

    Søndergaard, Lise; Ståhlberg, F; Thomsen, C

    1999-01-01

    The optimum management of patients with valvular heart diseases requires accurate and reproducible assessment of the valvular lesion and its hemodynamic consequences. Magnetic resonance imaging (MRI) techniques, such as volume measurements, signal-void phenomena, and velocity mapping, can be used...... in an integrated approach to gain qualitative and quantitative information on valvular heart disease as well as ventricular dimensions and functions. Thus, MRI may be advantageous to the established diagnostic tools in assessing the severity of valvular heart disease as well as monitoring the lesion and predicting...... the optimal timing for valvular surgery. This paper reviews the validation of these MRI techniques in assessing valvular heart disease and discusses some typical pitfalls of the techniques, including suggestions for solutions.J. Magn. Reson. Imaging 1999;10:627-638....

  16. Nanodiamond graphitization: a magnetic resonance study

    International Nuclear Information System (INIS)

    We report on the first nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) study of the high-temperature nanodiamond-to-onion transformation. 1H, 13C NMR and EPR spectra of the initial nanodiamond samples and those annealed at 600, 700, 800 and 1800 ° C were measured. For the samples annealed at 600 to 800 ° C, our NMR data reveal the early stages of the surface modification, as well as a progressive increase in sp2 carbon content with increased annealing temperature. Such quantitative experimental data were recorded for the first time. These findings correlate with EPR data on the sensitivity of the dangling bond EPR line width to air content, progressing with rising annealing temperature, that evidences consequent graphitization of the external layers of the diamond core. The sample annealed at 1800 ° C shows complete conversion of nanodiamond particles into carbon onions. (paper)

  17. Molecular structure and motion in zero field magnetic resonance

    International Nuclear Information System (INIS)

    Zero field magnetic resonance is well suited for the determination of molecular structure and the study of motion in disordered materials. Experiments performed in zero applied magnetic field avoid the anisotropic broadening in high field nuclear magnetic resonance (NMR) experiments. As a result, molecular structure and subtle effects of motion are more readily observed

  18. Magnetic Field Gradient Calibration as an Experiment to Illustrate Magnetic Resonance Imaging

    Science.gov (United States)

    Seedhouse, Steven J.; Hoffmann, Markus M.

    2008-01-01

    A nuclear magnetic resonance (NMR) spectroscopy experiment for the undergraduate physical chemistry laboratory is described that encompasses both qualitative and quantitative pedagogical goals. Qualitatively, the experiment illustrates how images are obtained in magnetic resonance imaging (MRI). Quantitatively, students experience the…

  19. Cardiovascular magnetic resonance in systemic hypertension

    Directory of Open Access Journals (Sweden)

    Maceira Alicia M

    2012-06-01

    Full Text Available Abstract Systemic hypertension is a highly prevalent potentially modifiable cardiovascular risk factor. Imaging plays an important role in the diagnosis of underlying causes for hypertension, in assessing cardiovascular complications of hypertension, and in understanding the pathophysiology of the disease process. Cardiovascular magnetic resonance (CMR provides accurate and reproducible measures of ventricular volumes, mass, function and haemodynamics as well as uniquely allowing tissue characterization of diffuse and focal fibrosis. In addition, CMR is well suited for exclusion of common secondary causes for hypertension. We review the current and emerging clinical and research applications of CMR in hypertension.

  20. Nuclear magnetic resonance common laboratory, quadrennial report

    International Nuclear Information System (INIS)

    This quadrennial report of the nuclear magnetic resonance common laboratory gives an overview of the main activities. Among the different described activities, only one is interesting for the INIS database: it concerns the Solid NMR of cements used for radioactive wastes storage. In this case, the NMR is used to characterize the structure of the material and the composition, structure and kinetics of formation of the alteration layer which is formed at the surface of concrete during water leaching conditions. The NMR methodology is given. (O.M.)

  1. Cardiac magnetic resonance in clinical cardiology

    Institute of Scientific and Technical Information of China (English)

    Andreas; Kumar; Rodrigo; Bagur

    2015-01-01

    Over the last decades, cardiac magnetic resonance(CMR) has transformed from a research tool to a widely used diagnostic method in clinical cardiology. This method can now make useful, unique contributions to the work-up of patients with ischemic and non-ischemic heart disease. Advantages of CMR, compared to other imaging methods, include very high resolution imaging with a spatial resolution up to 0.5 mm × 0.5 mm in plane, a large array of different imaging sequences to provide in vivo tissue characterization, and radiationfree imaging. The present manuscript highlights the relevance of CMR in the current clinical practice and new perspectives in cardiology.

  2. Developments in boron magnetic resonance imaging (MRI)

    Energy Technology Data Exchange (ETDEWEB)

    Schweizer, M.

    1995-11-01

    This report summarizes progress during the past year on maturing Boron-11 magnetic resonance imaging (MRI) methodology for noninvasive determination of BNCT agents (BSH) spatially in time. Three major areas are excerpted: (1) Boron-11 MRI of BSH distributions in a canine intracranial tumor model and the first human glioblastoma patient, (2) whole body Boron-11 MRI of BSH pharmacokinetics in a rat flank tumor model, and (3) penetration of gadolinium salts through the BBB as a function of tumor growth in the canine brain.

  3. Fetal magnetic resonance imaging and human genetics

    Energy Technology Data Exchange (ETDEWEB)

    Hengstschlaeger, Markus [Medical Genetics, Obstetrics and Gynecology, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna (Austria)]. E-mail: markus.hengstschlaeger@meduniwien.ac.at

    2006-02-15

    The use of fetal magnetic resonance imaging (MRI), in addition to prenatal genetic testing and sonography, has the potential to improve prenatal diagnosis of genetic disorders. MRI plays an important role in the evaluation of fetal abnormalities and malformations. Fetal MRI often enables a differential diagnosis, a determination of the extent of the disorder, the prognosis, and an improvement in therapeutic management. For counseling of parents, as well as to basically understand how genetic aberrations affect fetal development, it is of great importance to correlate different genotypes with fetal MRI data.

  4. Magnetic resonance imaging findings in Kimura's disease

    International Nuclear Information System (INIS)

    Although early diagnosis of Kimura's disease, a rare chronic inflammatory disorder most commonly presenting with asymmetric swelling in the head and neck region, is helpful in avoiding unnecessary diagnostic tests and starting prompt treatment, only a few reports emphasized radiological findings in detail. Magnetic resonance imaging findings showing the infiltrative nature of the disease and diffuse loss of fat tissue even in nonpalpable normally appearing regions of the head and neck in a young man with Kimura's disease are presented in this report. (orig.)

  5. Magnetic resonance imaging of cervical myelopathy

    Energy Technology Data Exchange (ETDEWEB)

    Chosa, Hirofumi; Yamano, Kouichirou; Ihara, Fumitoshi; Ueda, Yoshiaki; Maekawa, Masayuki; Tokuhisa, Ginichirou; Kuwano, Tadashi; Kamo, Yoshi; Nomura, Shigeharu (Kyushu Rosai Hospital, Fukuoka (Japan))

    1990-03-01

    Forty-three patients operated for cervical myelopathy were examined with a 1.5 T magnetic resonance imaging. Cord compression was demonstrated directly on the sagittal image in cases of cervical disc herniation, cervical spondylosis and O.P. L.L. Herniated disc material was seen positive on axial image. But factors of cord compression in cases of cervical spondylosis and O.P. L.L. were not clearly confirmed, so additional examinations such as myelogram, tomogram and CT was needed. (author).

  6. Nuclear Magnetic Resonance in Liquids and Solids

    International Nuclear Information System (INIS)

    The paper outlines the basic principles of nuclear magnetic resonance, trying wherever possible to compare and contrast the method with that of slow neutron scattering as a technique for studying the properties of condensed phases and especially of molecular and atomic motions. It is emphasized that this is not a review of nmr for an expert audience but has a pedagogical aim. It is hoped to give persons with a main interest in neutron scattering some appreciation of the scope and limitations of the nmr method. This is illustrated by recent results on one substance which covers many but by no means all of the important points. (author)

  7. Structural magnetic resonance imaging in epilepsy

    Energy Technology Data Exchange (ETDEWEB)

    Deblaere, Karel [Ghent University Hospital, Department of Neuroradiology, Ghent (Belgium); Ghent University Hospital, MR Department - 1K12, Ghent (Belgium); Achten, Eric [Ghent University Hospital, Department of Neuroradiology, Ghent (Belgium)

    2008-01-15

    Because of its sensitivity and high tissue contrast, magnetic resonance imaging (MRI) is the technique of choice for structural imaging in epilepsy. In this review the effect of using optimised scanning protocols and the use of high field MR systems on detection sensitivity is discussed. Also, the clinical relevance of adequate imaging in patients with focal epilepsy is highlighted. The most frequently encountered MRI findings in epilepsy are reported and their imaging characteristics depicted. Imaging focus will be on the diagnosis of hippocampal sclerosis and malformations of cortical development, two major causes of medically intractable focal epilepsy. (orig.)

  8. Structural magnetic resonance imaging in epilepsy

    International Nuclear Information System (INIS)

    Because of its sensitivity and high tissue contrast, magnetic resonance imaging (MRI) is the technique of choice for structural imaging in epilepsy. In this review the effect of using optimised scanning protocols and the use of high field MR systems on detection sensitivity is discussed. Also, the clinical relevance of adequate imaging in patients with focal epilepsy is highlighted. The most frequently encountered MRI findings in epilepsy are reported and their imaging characteristics depicted. Imaging focus will be on the diagnosis of hippocampal sclerosis and malformations of cortical development, two major causes of medically intractable focal epilepsy. (orig.)

  9. Magnetic Resonance of Pelvic and Gastrointestinal Emergencies.

    Science.gov (United States)

    Wongwaisayawan, Sirote; Kaewlai, Rathachai; Dattwyler, Matthew; Abujudeh, Hani H; Singh, Ajay K

    2016-05-01

    Magnetic resonance (MR) imaging is gaining increased acceptance in the emergency setting despite the continued dominance of computed tomography. MR has the advantages of more precise tissue characterization, superior soft tissue contrast, and a lack of ionizing radiation. Traditional barriers to emergent MR are being overcome by streamlined imaging protocols and newer rapid-acquisition sequences. As the utilization of MR imaging in the emergency department increases, a strong working knowledge of the MR appearance of the most commonly encountered abdominopelvic pathologies is essential. In this article, MR imaging protocols and findings of acute pelvic, scrotal, and gastrointestinal pathologies are discussed. PMID:27150327

  10. Magnetic resonance spectroscopy studies in migraine

    Energy Technology Data Exchange (ETDEWEB)

    Montagna, P.; Cortelli, P.; Barbiroli, B. (Inst. of Medical Pathology, Univ. of Bologna (Italy))

    1994-06-01

    The authors describe the method of [sup 31]phosphorus magnetic resonance spectroscopy and review the results when it is applied to the study of brain and muscle energy metabolism in migraine subjects. Brain energy metabolism appears to be abnormal in all major subtypes of migraine when measured both during and between attacks. Impaired energy metabolism is also documented in skeletal muscle. It is suggested that migraine is associated with a generalized disorder of mitochondrial oxidative phosphorylation and that this may constitute a threshold for the triggering of migraine attacks. 47 refs., 10 figs., 3 tabs.

  11. Magnetic resonance imaging in rheumatology. An overview.

    Science.gov (United States)

    Nissenbaum, M A; Adamis, M K

    1994-05-01

    Magnetic resonance (MR) imaging has revolutionized the assessment of pathology involving the musculoskeletal system. The soft tissue contrast, superb resolution, multiplanar acquisition potential, and the ability to monitor physiologic processes combine the best features of other imaging modalities. The sensitivity and specificity of MR imaging for a wide range of disease processes matches or supersedes conventional radiology, nuclear medicine, and clinical examination. This article provides a brief overview of the use of MR imaging for some of the more common clinical situations confronting the rheumatologist.

  12. Magnetic resonance imaging of acoustic neuroma

    Energy Technology Data Exchange (ETDEWEB)

    Kashihara, Kengo; Murata, Hideaki; Ito, Haruhide; Onishi, Hiroaki; Kadoya, Masumi; Suzuki, Masayuki.

    1989-03-01

    Thirteen patients with acoustic neuroma were studied on a 1.5T superconductive magnetic resonance (MR) imager. Acoustic neuromas appeared as lower signal intensity than the surrounding brain stem on T1 weighted image (W.I.), and as higher signal intensity on T2 W.I.. Axial and coronal sections of T1 W.I. were very useful in observing the tumor in the auditory canal and in investigating the anatomical relations of the tumor and the surrounding structures. MR imaging is very excellent examination to make early diagnosis of the acoustic neuroma and preoperative anatomical evaluation.

  13. Magnetic resonance-guided prostate interventions.

    Science.gov (United States)

    Haker, Steven J; Mulkern, Robert V; Roebuck, Joseph R; Barnes, Agnieska Szot; Dimaio, Simon; Hata, Nobuhiko; Tempany, Clare M C

    2005-10-01

    We review our experience using an open 0.5-T magnetic resonance (MR) interventional unit to guide procedures in the prostate. This system allows access to the patient and real-time MR imaging simultaneously and has made it possible to perform prostate biopsy and brachytherapy under MR guidance. We review MR imaging of the prostate and its use in targeted therapy, and describe our use of image processing methods such as image registration to further facilitate precise targeting. We describe current developments with a robot assist system being developed to aid radioactive seed placement. PMID:16924169

  14. MRCP. Magnetic resonance cholangiopancreatography; MRCP. Magnetresonanzcholangiopankreatografie

    Energy Technology Data Exchange (ETDEWEB)

    Kinner, Sonja [Wisconsin-Madison Univ., Madison, WI (United States). Dept. of Radiology; Lauenstein, Thomas [Evangelisches Krankenhaus Duesseldorf (Germany). Radiologie

    2016-06-15

    Magnetic resonance cholangiopancreatography (MRCP) is a special MR technique to display and analyze the biliary tract and pancreatic ducts. MRCP sequences are equivalent to endoscopic retrograde cholangiopancreatography (ERCP) for diagnostic purposes due to technical developments of the classical T2 weighted MRCP sequences and the availability of contrast enhanced T1 weighted sequences. Therefore, MRCP plays a fundamental role in the diagnoses of hepatobliary and pancreatic diseases, which are presented in this review article as are technical details of sequence acquisitions and the underlying anatomy.

  15. In vivo nuclear magnetic resonance imaging

    Science.gov (United States)

    Leblanc, A.

    1986-01-01

    During the past year the Woodlands Baylor Magnetic Resonance Imaging (MRI) facility became fully operational. A detailed description of this facility is given. One significant instrument addition this year was the 100 MHz, 40cm bore superconducting imaging spectrometer. This instrument gives researchers the capability to acquire high energy phosphate spectra. This will be used to investigate ATP, phosphocreatinine and inorganic phosphate changes in normal and atrophied muscle before, during and after exercise. An exercise device for use within the bore of the imaging magnet is under design/construction. The results of a study of T sub 1 and T sub 2 changes in atrophied muscle in animals and human subjects are given. The imaging and analysis of the lower leg of 15 research subjects before and after 5 weeks of complete bedrest was completed. A compilation of these results are attached.

  16. Enhancement of magnetic resonance imaging with metasurfaces

    CERN Document Server

    Slobozhanyuk, A P; Raaijmakers, A J E; Berg, C A T van den; Kozachenko, A V; Dubrovina, I A; Melchakova, I V; Kivshar, Yu S; Belov, P A

    2015-01-01

    Magnetic resonance imaging (MRI) is the cornerstone technique for diagnostic medicine, biology, and neuroscience. This imaging method is highly innovative, noninvasive and its impact continues to grow. It can be used for measuring changes in the brain after enhanced neural activity, detecting early cancerous cells in tissue, as well as for imaging nanoscale biological structures, and controlling fluid dynamics, and it can be beneficial for cardiovascular imaging. The MRI performance is characterized by a signal-to-noise ratio, however the spatial resolution and image contrast depend strongly on the scanner design. Here, we reveal how to exploit effectively the unique properties of metasurfaces for the substantial improvement of MRI efficiency. We employ a metasurface created by an array of wires placed inside the MRI scanner under an object, and demonstrate a giant enhancement of the magnetic field by means of subwavelength near-field manipulation with the metasurface, thus strongly increasing the scanner sen...

  17. Magnetic levitation of metamaterial bodies enhanced with magnetostatic surface resonances

    CERN Document Server

    Urzhumov, Yaroslav; Bingham, Chris; Padilla, Willie; Smith, David R

    2011-01-01

    We propose that macroscopic objects built from negative-permeability metamaterials may experience resonantly enhanced magnetic force in low-frequency magnetic fields. Resonant enhancement of the time-averaged force originates from magnetostatic surface resonances (MSR) which are analogous to the electrostatic resonances of negative-permittivity particles, well known as surface plasmon resonances in optics. We generalize the classical problem of MSR of a homogeneous object to include anisotropic metamaterials, and consider the most extreme case of anisotropy where the permeability is negative in one direction but positive in the others. It is shown that deeply subwavelength objects made of such indefinite (hyperbolic) media exhibit a pronounced magnetic dipole resonance that couples strongly to uniform or weakly inhomogeneous magnetic field and provides strong enhancement of the magnetic force, enabling applications such as enhanced magnetic levitation.

  18. Investigation of brain injury using in vivo multinuclear magnetic resonance imaging and spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Chew, W.M.

    1989-01-01

    Magnetic Resonance Imaging (MRI) and Spectroscopy (MRS) are becoming increasingly important tools to the fields of biochemistry, physiology, and medicine. MRI and MRS studies offer one the opportunity to obtain anatomic images and biochemical information non-invasively and non-destructively, thus making serial repeated measurements possible on the same experimental subject. To investigate brain injury, the non-invasiveness finally allows one to follow the time course of evolution of injury and its effects on the brains metabolism. Although MRI and MRS offer exciting opportunities, much work is needed to overcome the initial problems of signal localization from a specified region of interest. Also, the potential utility of multinuclear (i.e. {sup 13}C, {sup 19}F, {sup 23}Na...) MRI and MRS studies, in assessing brain injury, is yet to be determined. This thesis attacks the aforementioned problems with a series of studies both on phantoms and in vivo. Experiments were performed to determine optimal localization schemes for use in MRS of the brain to overcome the initial problems encountered with MRS studies. The feasibility and utility of multinuclear MRI and MRS was determined in vivo involving {sup 13}C, {sup 19}F, and {sup 23}Na nuclei. The results of these studies have proven that acceptable signal localization for MRS studies is achievable and is not a hindrance for future MRS studies. Also, multinuclear studies have shown that it is feasible to obtain MRI or MRS data from less abundant nuclei and that the information obtained does or can provide useful insights into brain metabolism in pathologic states.

  19. Magnetic resonance imaging of the central nervous system

    Energy Technology Data Exchange (ETDEWEB)

    Brant-Zawadzki, M.; Norman, D.

    1987-01-01

    This book presents the papers on technological advancement and diagnostic uses g magnetic resonance imaging. A comparative evaluation with computerized tomography is presented. Topics covered are imaging principles g magnetic resonance;instrumentation of magnetic resonance (MR);pathophysiology;quality and limitations g images;NMR imaging of brain and spinal cord;MR spectroscopy and its applications;neuroanatomy;Congenital malformations of brain and MR imaging;planning g MR imaging of spine and head and neck imaging.

  20. Clinical application of functional magnetic resonance imaging

    CERN Document Server

    Alwatban, A Z W

    2002-01-01

    The work described in this thesis was carried out at the Magnetic Resonance Centre of the University of Nottingham during the time from May 1998 to April 2001, and is the work of the except where indicated by reference. The main source of signal changes in functional magnetic resonance imaging (fMRJ) is the fluctuation of paramagnetic deoxyhaemoglobin in the venous blood during different states of functional performance. For the work of this thesis, fMRI studies were carried out using a 3 T MR system with an echo planar imaging (EPI) pulse sequence. Hearing research utilising fMRI has been previously reported in normal subjects. Hearing fMRI is normally performed by stimulating the auditory cortex via an acoustic task presentation such as music, tone, etc. However, performing the same research on deaf subjects requires special equipment to be designed to allow direct stimulation of the auditory nerve. In this thesis, a new method of direct electrical stimulation of the auditory nerve is described that uses a ...

  1. Magnetic Resonance Microscopy of the Lung

    Science.gov (United States)

    Johnson, G. Allan

    1999-11-01

    The lung presents both challenges and opportunities for study by magnetic resonance imaging (MRI). The technical challenges arise from respiratory and cardiac motion, limited signal from the tissues, and unique physical structure of the lung. These challenges are heightened in magnetic resonance microscopy (MRM) where the spatial resolution may be up to a million times higher than that of conventional MRI. The development of successful techniques for MRM of the lung present enormous opportunities for basic studies of lung structure and function, toxicology, environmental stress, and drug discovery by permitting investigators to study this most essential organ nondestructively in the live animal. Over the last 15 years, scientists at the Duke Center for In Vivo Microscopy have developed techniques for MRM in the live animal through an interdisciplinary program of biology, physics, chemistry, electrical engineering, and computer science. This talk will focus on the development of specialized radiofrequency coils for lung imaging, projection encoding methods to limit susceptibility losses, specialized support structures to control and monitor physiologic motion, and the most recent development of hyperpolarized gas imaging with ^3He and ^129Xe.

  2. Magnetic Resonance Imaging Evaluation of Cardiac Masses

    Energy Technology Data Exchange (ETDEWEB)

    Braggion-Santos, Maria Fernanda, E-mail: ferbraggion@yahoo.com.br [Divisão de Cardiologia do Departamento de Clínica Médica - Hospital das Clínicas - Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Hospital Universitário - Universidade de Heidelberg, Heidelberg (Germany); Koenigkam-Santos, Marcel [Centro de Ciências das Imagens e Física Médica - Hospital das Clínicas - Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Hospital Universitário - Universidade de Heidelberg, Heidelberg (Germany); Teixeira, Sara Reis [Centro de Ciências das Imagens e Física Médica - Hospital das Clínicas - Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Volpe, Gustavo Jardim [Divisão de Cardiologia do Departamento de Clínica Médica - Hospital das Clínicas - Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Divisão de Cardiologia - Universidade Johns Hopkins, Baltimore (United States); Trad, Henrique Simão [Centro de Ciências das Imagens e Física Médica - Hospital das Clínicas - Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Schmidt, André [Divisão de Cardiologia do Departamento de Clínica Médica - Hospital das Clínicas - Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil)

    2013-09-15

    Cardiac tumors are extremely rare; however, when there is clinical suspicion, proper diagnostic evaluation is necessary to plan the most appropriate treatment. In this context, cardiovascular magnetic resonance imaging (CMRI) plays an important role, allowing a comprehensive characterization of such lesions. To review cases referred to a CMRI Department for investigation of cardiac and paracardiac masses. To describe the positive case series with a brief review of the literature for each type of lesion and the role of cardiovascular magnetic resonance imaging in evaluation. Between August 2008 and December 2011, all cases referred for CMRI with suspicion of tumor involving the heart were reviewed. Cases with positive histopathological diagnosis, clinical evolution or therapeutic response compatible with the clinical suspicion and imaging findings were selected. Among the 13 cases included in our study, eight (62%) had histopathological confirmation. We describe five benign tumors (myxomas, rhabdomyoma and fibromas), five malignancies (sarcoma, lymphoma, Richter syndrome involving the heart and metastatic disease) and three non-neoplastic lesions (pericardial cyst, intracardiac thrombus and infectious vegetation). CMRI plays an important role in the evaluation of cardiac masses of non-neoplastic and neoplastic origin, contributing to a more accurate diagnosis in a noninvasive manner and assisting in treatment planning, allowing safe clinical follow-up with good reproducibility.

  3. Magnetic resonance imaging findings in adnexial torsion

    Energy Technology Data Exchange (ETDEWEB)

    Trindade, Ronald Meira Castro; Quadros, Marianne Siquara de [Hospital Albert Einstein, Sao Paulo, SP (Brazil). Instituto de Ensino e Pesquisa], e-mail: rtrindade@einstein.br; Baroni, Ronaldo Hueb; Rosemberg, Michelle; Racy, Marcelo de Castro Jorge; Tachibana, Adriano [Hospital Albert Einstein, Sao Paulo, SP (Brazil); Funari, Marcelo Buarque de Gusmao [Hospital Albert Einstein, Sao Paulo, SP (Brazil). Imaging Service

    2010-01-15

    Adnexial torsion is an unusual event, but a major cause of abdominal pain in women. It is often associated with ovarian tumor or cyst, but can occur in normal ovaries, especially in children. The twisting of adnexial structures may involve the ovary or tube, but frequently affects both. In most cases, it is unilateral, with slight predilection for the right size. In imaging findings, increased ovarian volume and adnexial masses are observed, with reduced or absent vascularisation. In cases of undiagnosed or untreated complete twist, hemorrhagic necrosis may occur leading to complications; in that, peritonitis is the most frequent. Early diagnosis helps preventing irreversible damage with conservative treatment, thereby saving the ovary. Limitations in performing physical examination, possible inconclusive results in ultrasound and exposure to radiation in computed tomography makes magnetic resonance imaging a valuable tool in emergency assessment of gynecological diseases. The objective of this study was to report two confirmed cases of adnexial twist, emphasizing the contribution of magnetic resonance imaging in the diagnosis of this condition. (author)

  4. General review of magnetic resonance elastography.

    Science.gov (United States)

    Low, Gavin; Kruse, Scott A; Lomas, David J

    2016-01-28

    Magnetic resonance elastography (MRE) is an innovative imaging technique for the non-invasive quantification of the biomechanical properties of soft tissues via the direct visualization of propagating shear waves in vivo using a modified phase-contrast magnetic resonance imaging (MRI) sequence. Fundamentally, MRE employs the same physical property that physicians utilize when performing manual palpation - that healthy and diseased tissues can be differentiated on the basis of widely differing mechanical stiffness. By performing "virtual palpation", MRE is able to provide information that is beyond the capabilities of conventional morphologic imaging modalities. In an era of increasing adoption of multi-parametric imaging approaches for solving complex problems, MRE can be seamlessly incorporated into a standard MRI examination to provide a rapid, reliable and comprehensive imaging evaluation at a single patient appointment. Originally described by the Mayo Clinic in 1995, the technique represents the most accurate non-invasive method for the detection and staging of liver fibrosis and is currently performed in more than 100 centers worldwide. In this general review, the mechanical properties of soft tissues, principles of MRE, clinical applications of MRE in the liver and beyond, and limitations and future directions of this discipline -are discussed. Selected diagrams and images are provided for illustration. PMID:26834944

  5. Magnetic resonance imaging of the bone marrow

    Energy Technology Data Exchange (ETDEWEB)

    Baur-Melnyk, Andrea (ed.) [Klinikum der Univ. Muenchen (Germany). Inst. fuer Klinische Radiologie

    2013-08-01

    The first book devoted to MRI of the bone marrow. Describes the MRI appearances of normal bone marrows and the full range of bone marrow disorders. Discusses the role of advanced MRI techniques and contrast enhancement. On account of its unrivalled imaging capabilities and sensitivity, magnetic resonance imaging (MRI) is considered the modality of choice for the investigation of physiologic and pathologic processes affecting the bone marrow. This book describes the MRI appearances of both the normal bone marrow, including variants, and the full range of bone marrow disorders. Detailed discussion is devoted to malignancies, including multiple myeloma, lymphoma, chronic myeloproliferative disorders, leukemia, and bone metastases. Among the other conditions covered are benign and malignant compression fractures, osteonecrosis, hemolytic anemia, Gaucher's disease, bone marrow edema syndrome, trauma, and infective and non-infective inflammatory disease. Further chapters address the role of MRI in assessing treatment response, the use of contrast media, and advanced MRI techniques. Magnetic Resonance Imaging of the Bone Marrow represents an ideal reference for both novice and experienced practitioners.

  6. Magnetic resonance imaging of congenital cardiac abnormalities

    International Nuclear Information System (INIS)

    Magnetic resonance imaging will not replace echocardiography as the simplest and most definitive method of establishing a noninvasive diagnosis in young patients with congenital cardiac malformations, nor will it replace radionuclide angiography for relatively noninvasive detection and quantitation of cardiac shunts. Magnetic resonance imaging is a complementary noninvasive imaging procedure that can answer some questions left in doubt by echocardiography (mainly extracardiac artery and vein assessments) or radionuclide angiography and used as a preferred follow-up imaging method in certain clinical circumstances. In addition, MRI can be a first-line modality for cardiovascular imaging in older patients in whom adequate echo windows are not available. Angiocardiography remains necessary to provide vital physiological data, i.e., chamber pressures, shunt volumes, oxygen saturations, and pulmonary vascular resistance; however, MRI could negate some follow-up catheterizations in appropriate clinical circumstances. High-resolution proton MRI tomography should ultimately permit the accurate evaluation of ventricular volumes, myocardial mass, and the assessment of regional wall motion and ejection fractions. Paramagnetic substances such as manganese ion may ultimately provide a basis for myocardial perfusion imaging. The potential for MRI evaluation of tissue characterization, noninvasive blood-flow measurements, and myocardial metabolism assessment in intriguing and awaits clinical evaluation

  7. Resonances and dipole moments in dielectric, magnetic, and magnetodielectric cylinders

    DEFF Research Database (Denmark)

    Dirksen, A.; Arslanagic, Samel; Breinbjerg, Olav

    2011-01-01

    An eigenfunction solution to the problem of plane wave scattering by dielectric, magnetic, and magnetodielectric cylinders is used for a systematic investigation of their resonances. An overview of the resonances with electric and magnetic dipole moments, needed in, e.g., the synthesis of metamat......An eigenfunction solution to the problem of plane wave scattering by dielectric, magnetic, and magnetodielectric cylinders is used for a systematic investigation of their resonances. An overview of the resonances with electric and magnetic dipole moments, needed in, e.g., the synthesis...

  8. Ultra-high-field magnetic resonance: Why and when?

    OpenAIRE

    Moser, Ewald

    2010-01-01

    This paper briefly summarizes the development of magnetic resonance imaging and spectroscopy in medicine. Aspects of magnetic resonancephysics and -technology relevant at ultra-high magnetic fields as well as current limitations are highlighted. Based on the first promising studies, potential clinical applications at 7 Tesla are suggested. Other aims are to stimulate awareness of the potential of ultra-high field magnetic resonance and to stimulate active participation in much needed basic or...

  9. Purely electric and magnetic dipole resonances in metamaterial dielectric resonators through perturbation theory inspired geometries

    CERN Document Server

    Campione, Salvatore; Warne, Larry K; Sinclair, Michael B

    2014-01-01

    In this paper we describe a methodology for tailoring the design of metamaterial dielectric resonators, which represent a promising path toward low-loss metamaterials at optical frequencies. We first describe a procedure to decompose the far field scattered by subwavelength resonators in terms of multipolar field components, providing explicit expressions for the multipolar far fields. We apply this formulation to confirm that an isolated high-permittivity cube resonator possesses frequency separated electric and magnetic dipole resonances, as well as a magnetic quadrupole resonance in close proximity to the electric dipole resonance. We then introduce multiple dielectric gaps to the resonator geometry in a manner suggested by perturbation theory, and demonstrate the ability to overlap the electric and magnetic dipole resonances, thereby enabling directional scattering by satisfying the first Kerker condition. We further demonstrate the ability to push the quadrupole resonance away from the degenerate dipole ...

  10. Spatial localization in nuclear magnetic resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Keevil, Stephen F [Department of Medical Physics, Guy' s and St Thomas' NHS Foundation Trust, Guy' s Hospital, London, SE1 9RT (United Kingdom); Division of Imaging Sciences, King' s College London, Guy' s Campus, London, SE1 9RT (United Kingdom)

    2006-08-21

    The ability to select a discrete region within the body for signal acquisition is a fundamental requirement of in vivo NMR spectroscopy. Ideally, it should be possible to tailor the selected volume to coincide exactly with the lesion or tissue of interest, without loss of signal from within this volume or contamination with extraneous signals. Many techniques have been developed over the past 25 years employing a combination of RF coil properties, static magnetic field gradients and pulse sequence design in an attempt to meet these goals. This review presents a comprehensive survey of these techniques, their various advantages and disadvantages, and implications for clinical applications. Particular emphasis is placed on the reliability of the techniques in terms of signal loss, contamination and the effect of nuclear relaxation and J-coupling. The survey includes techniques based on RF coil and pulse design alone, those using static magnetic field gradients, and magnetic resonance spectroscopic imaging. Although there is an emphasis on techniques currently in widespread use (PRESS, STEAM, ISIS and MRSI), the review also includes earlier techniques, in order to provide historical context, and techniques that are promising for future use in clinical and biomedical applications. (topical review)

  11. {sup 19}F-labeling of the adenine H2-site to study large RNAs by NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Sochor, F. [Johann Wolfgang Goethe-University Frankfurt, Institut für Organische Chemie und Chemische Biologie, Center for Biomolecular Magnetic Resonance (BMRZ) (Germany); Silvers, R. [Massachusetts Institute of Technology, Department of Chemistry, Francis Bitter Magnet Laboratory (United States); Müller, D.; Richter, C.; Fürtig, B., E-mail: fuertig@nmr.uni-frankfurt.de; Schwalbe, H., E-mail: schwalbe@nmr.uni-frankfurt.de [Johann Wolfgang Goethe-University Frankfurt, Institut für Organische Chemie und Chemische Biologie, Center for Biomolecular Magnetic Resonance (BMRZ) (Germany)

    2016-01-15

    In comparison to proteins and protein complexes, the size of RNA amenable to NMR studies is limited despite the development of new isotopic labeling strategies including deuteration and ligation of differentially labeled RNAs. Due to the restricted chemical shift dispersion in only four different nucleotides spectral resolution remains limited in larger RNAs. Labeling RNAs with the NMR-active nucleus {sup 19}F has previously been introduced for small RNAs up to 40 nucleotides (nt). In the presented work, we study the natural occurring RNA aptamer domain of the guanine-sensing riboswitch comprising 73 nucleotides from Bacillus subtilis. The work includes protocols for improved in vitro transcription of 2-fluoroadenosine-5′-triphosphat (2F-ATP) using the mutant P266L of the T7 RNA polymerase. Our NMR analysis shows that the secondary and tertiary structure of the riboswitch is fully maintained and that the specific binding of the cognate ligand hypoxanthine is not impaired by the introduction of the {sup 19}F isotope. The thermal stability of the {sup 19}F-labeled riboswitch is not altered compared to the unmodified sequence, but local base pair stabilities, as measured by hydrogen exchange experiments, are modulated. The characteristic change in the chemical shift of the imino resonances detected in a {sup 1}H,{sup 15}N-HSQC allow the identification of Watson–Crick base paired uridine signals and the {sup 19}F resonances can be used as reporters for tertiary and secondary structure transitions, confirming the potential of {sup 19}F-labeling even for sizeable RNAs in the range of 70 nucleotides.

  12. Magnetic resonance tracking of fluorescent nanodiamond fabrication

    International Nuclear Information System (INIS)

    Magnetic resonance techniques (electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR)) are used for tracking the multi-stage process of the fabrication of fluorescent nanodiamonds (NDs) produced by high-energy electron irradiation, annealing, and subsequent nano-milling. Pristine commercial high pressure and high temperature microdiamonds (MDs) with mean size 150 μm contain ∼5  ×  1018 spins/g of singlet (S = 1/2) substitutional nitrogen defects P1, as well as sp3 C–C dangling bonds in the crystalline lattice. The half-field X-band EPR clearly shows (by the appearance of the intense ‘forbidden’ g = 4.26 line) that high-energy electron irradiation and annealing of MDs induce a large amount (∼5  ×  1017 spins/g) of triplet (S = 1) magnetic centers, which are identified as negatively charged nitrogen vacancy defects (NV−). This is supported by EPR observations of the ‘allowed’ transitions between Zeeman sublevels of the triplet state. After progressive milling of the fluorescent MDs down to an ultrasubmicron scale (≤100 nm), the relative abundance of EPR active NV− defects in the resulting fluorescent NDs (FND) substantially decreases and, vice versa, the content of C-inherited singlet defects correlatively increases. In the fraction of the finest FNDs (mean particle size <20 nm), which are contained in the dried supernatant of ultracentrifuged aqueous dispersion of FNDs, the NV− content is found to be reduced by one order of magnitude whereas the singlet defects content increases up to ∼2  ×  1019 spins/g. In addition, another triplet-type defect, which is characterized by the g = 4.00 ‘forbidden’ line, appears. On reduction of the particle size below the 20 nm limit, the ‘allowed’ EPR lines become practically unobservable, whereas the ‘forbidden’ lines remain as a reliable fingerprint of the presence of NV− centers in small ND systems. The same size reduction causes the

  13. Basic concepts from magnetic resonance imaging

    International Nuclear Information System (INIS)

    The use of magnetic resonance imaging (MRI) has grown exponentially, due in part to excellent anatomic and pathologic detail provided by the modality, as recent technological advances that have led to more rapid acquisition times. Radiology residents in different parts of the world now receive training in MR images from their first year of residence, included the pulse sequences training spin-echo, gradient-echo, inversion-recovery, echo-planar image and MR angiographic sequences, commonly used in medical imaging. However, to optimize the use of this type of study, it has been necessary to understand the basic concepts of physics, included the concepts of recovery T1, degradation T2* and T2, repetition time, echo time, and the effects of chemical shift. Additionally, it has been important to understand the contrast weighting for better representation of specific tissues and thus perform an appropriate differential diagnosis of various pathological processes. (author)

  14. Valuation for magnetic resonance of neuro tuberculosis

    International Nuclear Information System (INIS)

    The increased incidence of neuro tuberculosis (NTB), due to the world epidemic of resistant strains and AIDS, has made of magnetic resonance (MR) imaging the study of choice for the early detection of lesions that lead the clinicians to an effective treatment. We present our experience with six cases of NTB, with meningoencephalic (4 cases), spinal, (1 case) and epidural (1 case) involvement. We identified basal arachnoiditis that was also seen on CT. Two cases demonstrated non-classifying tuberculomas, the spinal lesion consisted of casseifying tuberculoma that responded to treatment and disappeared on a follow up MR study. Epidural involvement consisted of Pott's disease with displacement and edema of the spinal cord. The differential diagnosis of these lesions includes mycoses, cysticercosis, sarcoidosis and leptomeningeal metastases

  15. Functional Magnetic Resonance Imaging in Consumer Research

    DEFF Research Database (Denmark)

    Reimann, Martin; Schilke, Oliver; Weber, Bernd;

    2011-01-01

    of prior fMRI research related to consumer behavior and highlights the features that make fMRI an attractive method for consumer and marketing research. The authors discuss advantages and limitations and illustrate the proposed procedures with an applied study, which investigates loss aversion when buying......Although the field of psychology is undergoing an immense shift toward the use of functional magnetic resonance imaging (fMRI), the application of this methodology to consumer research is relatively new. To assist consumer researchers in understanding fMRI, this paper elaborates on the findings...... and selling a common product. Results reveal a significantly stronger activation in the amygdala while consumers estimate selling prices versus buying prices, suggesting that loss aversion is associated with the processing of negative emotion. © 2011 Wiley Periodicals, Inc....

  16. Pulsed nuclear-electronic magnetic resonance

    CERN Document Server

    Morley, Gavin W; Mohammady, M Hamed; Aeppli, Gabriel; Kay, Christopher W M; Jeschke, Gunnar; Monteiro, Tania S

    2011-01-01

    Pulsed magnetic resonance is a wide-reaching technology allowing the quantum state of electronic and nuclear spins to be controlled on the timescale of nanoseconds and microseconds respectively. The time required to flip either dilute electronic or nuclear spins is orders of magnitude shorter than their decoherence times, leading to several schemes for quantum information processing with spin qubits. We investigate instead the novel regime where the eigenstates approximate 50:50 superpositions of the electronic and nuclear spin states forming "nuclear-electronic" qubits. Here we demonstrate quantum control of these states, using bismuth-doped silicon, in just 32 ns: orders of magnitude shorter than previous experiments where pure nuclear states were used. The coherence times of our states are over four orders of magnitude longer, being 1 ms or more at 8 K, and are limited by the naturally-occurring 29Si nuclear spin impurities. There is quantitative agreement between our experiments and no-free-parameter anal...

  17. Magnetic resonance imaging in patients with panhypopituitarism

    Energy Technology Data Exchange (ETDEWEB)

    Pozzi Mucelli, R.S. [Ist. di Radiologia, Univ. di Trieste, Ospedale di Cattinara (Italy); Frezza, F. [Ist. di Radiologia, Univ. di Trieste, Ospedale di Cattinara (Italy); Magnaldi, S. [Ist. di Radiologia, Univ. di Trieste, Ospedale di Cattinara (Italy); Proto, G. [Servizio di Endocrinologia, Ospedale Civile di Udine (Italy)

    1992-02-01

    Primary panhypopituitarism consists of functional deficiency of the anterior pituitary lobe, which appears during infancy or adolescence. The magnetic resonance findings in 10 patients with a history of primary hypopituitarism are presented. The findings include: reduced pituitary size in all cases; partially (8 cases) or totally (2 cases) empty sella; thin (4 cases), partially visible (3 cases) or absent (2 cases) pituitary stalk; absence of the posterior lobe in 9 cases; bright spot corresponding to an ectopic posterior lobe in 8 cases. These findings are similar to those already reported in pituitary dwarfism and may help understanding of the pathogenesis of the disease, which seems to be related to a pituitary stalk lesion. (orig.)

  18. Magnetic resonance imaging after exposure to microgravity

    Science.gov (United States)

    Leblanc, Adrian

    1993-01-01

    A number of physiological changes were demonstrated in bone, muscle, and blood from exposure of humans and animals to microgravity. Determining mechanisms and the development of effective countermeasures for long-duration space missions is an important NASA goal. Historically, NASA has had to rely on tape measures, x-ray, and metabolic balance studies with collection of excreta and blood specimens to obtain this information. The development of magnetic resonance imaging (MRI) offers the possibility of greatly extending these early studies in ways not previously possible; MRI is also non-invasive and safe; i.e., no radiation exposure. MRI provides both superb anatomical images for volume measurements of individual structures and quantification of chemical/physical changes induced in the examined tissues. This investigation will apply MRI technology to measure muscle, intervertebral disc, and bone marrow changes resulting from exposure to microgravity.

  19. Cardiovascular magnetic resonance in carotid atherosclerotic disease

    Directory of Open Access Journals (Sweden)

    Chen Huijun

    2009-12-01

    Full Text Available Abstract Atherosclerosis is a chronic, progressive, inflammatory disease affecting many vascular beds. Disease progression leads to acute cardiovascular events such as myocardial infarction, stroke and death. The diseased carotid alone is responsible for one third of the 700,000 new or recurrent strokes occurring yearly in the United States. Imaging plays an important role in the management of atherosclerosis, and cardiovascular magnetic resonance (CMR of the carotid vessel wall is one promising modality in the evaluation of patients with carotid atherosclerotic disease. Advances in carotid vessel wall CMR allow comprehensive assessment of morphology inside the wall, contributing substantial disease-specific information beyond luminal stenosis. Although carotid vessel wall CMR has not been widely used to screen for carotid atherosclerotic disease, many trials support its potential for this indication. This review summarizes the current state of knowledge regarding carotid vessel wall CMR and its potential clinical application for management of carotid atherosclerotic disease.

  20. Magnetic resonance imaging of brain death

    Energy Technology Data Exchange (ETDEWEB)

    Lee, D.H.; Nathanson, J.A.; Fox, A.J.; Pelz, D.M.; Lownie, S.P.

    1995-06-01

    In order to demonstrate the magnetic resonance imaging (MRI) appearance of the brain in patients with clinical brain death, high-field MRI was performed on 5 patients using conventional T1-weighted and T2-weighted imaging. The study showed MRI exhibited similar features for all of the patients, features which were not found in MRI of comatose patients who were not clinically brain dead. It was stated that up to now the most important limitation in MRI of patients with suspected brain death has been the extreme difficulty of moving them out of the intensive care setting. If this problem can be overcome, and it appears possible with with the advent of MRI-compatible ventilators and noninvasive monitoring, MRI could become an excellent alternative for confirming clinical diagnosis of brain death for such patients. 15 refs., 3 figs.

  1. Magnetic Earth Ionosphere Resonant Frequencies (MEIRF) project

    Science.gov (United States)

    Spaniol, Craig

    1993-01-01

    The West Virginia State College Community College Division NASA Magnetic Earth Ionosphere Resonant Frequencies (MEIRF) study is described. During this contract period, the two most significant and professionally rewarding events were the presentation of the research activity at the Sir Isaac Newton Conference in St. Petersburg, Russia, and the second Day of Discovery Conference, focusing on economic recovery in West Virginia. An active antenna concept utilizing a signal feedback principle similar to regenerative receivers used in early radio was studied. The device has potential for ELF research and other commercial applications for improved signal reception. Finally, work continues to progress on the development of a prototype monitoring station. Signal monitoring, data display, and data storage are major areas of activity. In addition, we plan to continue our dissemination of research activity through presentations at seminars and other universities.

  2. Magnetic resonance imaging of the heart.

    Science.gov (United States)

    Tscholakoff, D; Higgins, C B

    1985-01-01

    Magnetic resonance imaging (MRI) is a completely noninvasive technique for the evaluation of the cardiovascular system. With a multi-section technique and the spin echo pulse sequence the entire heart can be examined within six to ten minutes. All our cardiac MR studies were performed with electrocardiographic (ECG) gating, to obtain adequate resolution of the cardiac structures. With this technique, patients and animals with a variety of cardiac abnormalities were studied. The examined pathologic conditions included acute and chronic myocardial infarctions and their complications, hypertrophic and congestive cardiomyopathies, congenital heart diseases and pericardial diseases. MRI offers an enormous potential for cardiovascular diagnosis, even beyond the demonstration of pathoanatomy, because of the capability for direct tissue characterization and blood flow measurements.

  3. Magnetic resonance imaging of optic nerve

    Directory of Open Access Journals (Sweden)

    Foram Gala

    2015-01-01

    Full Text Available Optic nerves are the second pair of cranial nerves and are unique as they represent an extension of the central nervous system. Apart from clinical and ophthalmoscopic evaluation, imaging, especially magnetic resonance imaging (MRI, plays an important role in the complete evaluation of optic nerve and the entire visual pathway. In this pictorial essay, the authors describe segmental anatomy of the optic nerve and review the imaging findings of various conditions affecting the optic nerves. MRI allows excellent depiction of the intricate anatomy of optic nerves due to its excellent soft tissue contrast without exposure to ionizing radiation, better delineation of the entire visual pathway, and accurate evaluation of associated intracranial pathologies.

  4. Automated Segmentation of Cardiac Magnetic Resonance Images

    DEFF Research Database (Denmark)

    Stegmann, Mikkel Bille; Nilsson, Jens Chr.; Grønning, Bjørn A.

    2001-01-01

    Magnetic resonance imaging (MRI) has been shown to be an accurate and precise technique to assess cardiac volumes and function in a non-invasive manner and is generally considered to be the current gold-standard for cardiac imaging [1]. Measurement of ventricular volumes, muscle mass and function...... is based on determination of the left-ventricular endocardial and epicardial borders. Since manual border detection is laborious, automated segmentation is highly desirable as a fast, objective and reproducible alternative. Automated segmentation will thus enhance comparability between and within cardiac...... studies and increase accuracy by allowing acquisition of thinner MRI-slices. This abstract demonstrates that statistical models of shape and appearance, namely the deformable models: Active Appearance Models, can successfully segment cardiac MRIs....

  5. Magnetic Resonance Imaging in occult spinal dysraphism

    International Nuclear Information System (INIS)

    A prospective study was carried out in 100 cases of suspected occult spinal dysraphic anomalies with Magnetic Resonance Imaging (MRI) in order to determine its diagnostic efficacy as the initial imaging modality. MR imaging provided accurate preoperative information in 91 out of 92 cases (98.9%). Some of the unusual and interesting findings in the series were: presence of intrinsic cord abnormality in 19 out of 21 cases (90.4%) with a normal plain radiography, 4 cases of diastematomyelia with a dermoid in the dorsal and lumbar region associated with syringohydromyelia, intradural fibrous/glial bands, syringo-hydromyelia/myelomalacia of the conus with tethered cord syndrome having a normally paced conus, and myelocystocele. It is concluded that MRI is an excellent primary diagnostic tool, together with a plain radiography, for complete preoperative evaluation of mid-line spinal anomalies. 14 refs., 3 tabs., 7 figs

  6. Safety of magnetic resonance contrast media.

    Science.gov (United States)

    Runge, V M

    2001-08-01

    Intravenous contrast media, specifically the gadolinium chelates, are well accepted for use in the clinical practice of magnetic resonance imaging. The gadolinium chelates are considered to be very safe and lack (in intravenous use) the nephrotoxicity found with iodinated contrast media. Minor adverse reactions, including nausea and hives, occur in a low percentage of cases. The four agents currently available in the United States cannot be differentiated on the basis of these adverse reactions. Severe anaphylactoid reactions are also known to occur with all agents, although these are uncommon. This review discusses the safety issues involved with intravenous administration of the gadolinium chelates and off-label use. The latter is common in clinical practice and permits broader application of these agents. PMID:11687717

  7. Quantum information processing and nuclear magnetic resonance

    CERN Document Server

    Cummins, H K

    2001-01-01

    as spectrometer pulse sequence programs. Quantum computers are information processing devices which operate by and exploit the laws of quantum mechanics, potentially allowing them to solve problems which are intractable using classical computers. This dissertation considers the practical issues involved in one of the more successful implementations to date, nuclear magnetic resonance (NMR). Techniques for dealing with systematic errors are presented, and a quantum protocol is implemented. Chapter 1 is a brief introduction to quantum computation. The physical basis of its efficiency and issues involved in its implementation are discussed. NMR quantum information processing is reviewed in more detail in Chapter 2. Chapter 3 considers some of the errors that may be introduced in the process of implementing an algorithm, and high-level ways of reducing the impact of these errors by using composite rotations. Novel general expressions for stabilising composite rotations are presented in Chapter 4 and a new class o...

  8. Magnetic resonance imaging of intervertebral disc degeneration

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, Hiroshi; Noguchi, Masao (Kitakyushu City Yahata Hospital, Fukuoka (Japan)); Kira, Hideaki; Fujiki, Hiroshi; Shimokawa, Isao; Hinoue, Kaichi

    1993-02-01

    The aim of this study was to correlate the degree of lumbar intervertebral disc degeneration with findings of magnetic resonance imaging (MRI). Seventeen autopsied (from 7 patients) and 21 surgical (from 20 patients) intervertebral discs were used as specimens for histopathological examination. In addition, 21 intervertebral discs were examined on T2-weighted images. Histopathological findings from both autopsied and surgical specimens were well correlated with MRI findings. In particular, T2-weighted images reflected increased collagen fibers and rupture within the fibrous ring accurately. However, when severely degenerated intervertebral discs and hernia protruding the posterior longitudinal ligament existed, histological findings were not concordant well with T2-weighted images. Morphological appearances of autopsy specimens, divided into four on T2-weighted images, were well consistent with histological degeneration. This morphological classification, as shown on T2-weighted images, could also be used in the evaluation of intervertebral disc degeneration. (N.K.).

  9. Monitoring angiogenesis using magnetic resonance methods

    DEFF Research Database (Denmark)

    Holm, David Alberg

    2008-01-01

    -angiogenic treatment is presented in the first manuscript. In the second and third manuscript, two separate methods of quantifying perfusion, blood volume and vessel permeability are presented. The methods are used to show that drug delivery to a xenografted tumor is plausible and to show possible vascular maturation......When a tumor reaches a certain size it can no longer rely on passive perfusion for nutrition. The tumor therefore emits signaling molecules which stimulating surrounding vessels to divide and grow towards the tumor, a process known as angiogenesis. Very little angiogenesis is present in healthy...... and the involved signaling molecules. Subsequently, a short review of contrast agents and perfusion measurements is given. Finally, methods for monitoring angiogenesis using magnetic resonance imaging are reviewed. A method for monitoring early stages of angiogenesis as well as the effect of anti...

  10. Magnetic resonance imaging of pancreatitis: an update.

    Science.gov (United States)

    Manikkavasakar, Sriluxayini; AlObaidy, Mamdoh; Busireddy, Kiran K; Ramalho, Miguel; Nilmini, Viragi; Alagiyawanna, Madhavi; Semelka, Richard C

    2014-10-28

    Magnetic resonance (MR) imaging plays an important role in the diagnosis and staging of acute and chronic pancreatitis and may represent the best imaging technique in the setting of pancreatitis due to its unmatched soft tissue contrast resolution as well as non-ionizing nature and higher safety profile of intravascular contrast media, making it particularly valuable in radiosensitive populations such as pregnant patients, and patients with recurrent pancreatitis requiring multiple follow-up examinations. Additional advantages include the ability to detect early forms of chronic pancreatitis and to better differentiate adenocarcinoma from focal chronic pancreatitis. This review addresses new trends in clinical pancreatic MR imaging emphasizing its role in imaging all types of acute and chronic pancreatitis, pancreatitis complications and other important differential diagnoses that mimic pancreatitis. PMID:25356038

  11. Chest magnetic resonance imaging: a protocol suggestion

    Directory of Open Access Journals (Sweden)

    Bruno Hochhegger

    2015-12-01

    Full Text Available Abstract In the recent years, with the development of ultrafast sequences, magnetic resonance imaging (MRI has been established as a valuable diagnostic modality in body imaging. Because of improvements in speed and image quality, MRI is now ready for routine clinical use also in the study of pulmonary diseases. The main advantage of MRI of the lungs is its unique combination of morphological and functional assessment in a single imaging session. In this article, the authors review most technical aspects and suggest a protocol for performing chest MRI. The authors also describe the three major clinical indications for MRI of the lungs: staging of lung tumors; evaluation of pulmonary vascular diseases; and investigation of pulmonary abnormalities in patients who should not be exposed to radiation.

  12. Cardiovascular magnetic resonance in hypertrophic cardiomyopathy

    Energy Technology Data Exchange (ETDEWEB)

    Shiozaki, Afonso Akio; Parga, Jose Rodrigues; Arteaga, Edmundo; Rochitte, Carlos Eduardo [Sao Paulo Univ. (USP), SP (Brazil). Instituto do Coracao. Setor de Tomografia Computarizada e Ressonancia Magnetica Cardiovascular]. E-mail: rochitte@incor.usp.br; Kim, Raymond J. [Duke Cardiovascular Magnetic Resonance Center, Durham, NC (United States); Tassi, Eduardo Marinho [Diagnosticos da America S.A., Rio de Janeiro, RJ (Brazil). Sector of Cardiovascular Magnetic Resonance and Computed Tomography

    2007-03-15

    Hypertrophic cardiomyopathy (HCM) is the most frequent genetic cardiac disease that causes sudden death in young people, with an incidence of 1:500 adults. The routinely used criteria for worst prognosis have limited sensitivity and specificity. Thus, the estimated risk of evolving to dilated cardiomyopathy or sudden death is somewhat inaccurate, leading to management uncertainty of HCM patients. Therefore, an accurate noninvasive method for the diagnosis of HCM with prognostic value is of great importance. In the last years, Cardiovascular Magnetic Resonance (CMR) emerged not only as a diagnostic tool, but also as a study with prognostic values, by characterizing myocardial fibrosis with great accuracy in HCM patients. Additionally, CMR identifies the types of hypertrophy, analyses the ventricular function, estimates the intraventricular gradient and allows the determination of differential diagnosis. Moreover, CMR can uniquely access myocardial fibrosis in HCM. (author)

  13. Two-dimensional nuclear magnetic resonance petrophysics.

    Science.gov (United States)

    Sun, Boqin; Dunn, Keh-Jim

    2005-02-01

    Two-dimensional nuclear magnetic resonance (2D NMR) opens a wide area for exploration in petrophysics and has significant impact to petroleum logging technology. When there are multiple fluids with different diffusion coefficients saturated in a porous medium, this information can be extracted and clearly delineated from CPMG measurements of such a system either using regular pulsing sequences or modified two window sequences. The 2D NMR plot with independent variables of T2 relaxation time and diffusion coefficient allows clear separation of oil and water signals in the rocks. This 2D concept can be extended to general studies of fluid-saturated porous media involving other combinations of two or more independent variables, such as chemical shift and T1/T2 relaxation time (reflecting pore size), proton population and diffusion contrast, etc. PMID:15833623

  14. Magnetic resonance imaging of cerebrotendinous xanthomatosis

    Energy Technology Data Exchange (ETDEWEB)

    Tai, K.S.; Brockwell, J.; Chan, F.L.; Janus, E.D.; Lam, K.S.L.

    1995-02-01

    Cerebrotendinous xanthomatosis (CTX) is a rare genetic disorder in which cholestanol and cholesterol accumulate in the nervous system and other tissues. It has an autosomal recessive mode of inheritance. Most patients are of low intelligence with poor school performance. Specific clinical manifestations include xanthomas of the tendons. Furthermore, patients develop cataracts and a slowly progressive cerebellar ataxia. There is slight mental deterioration. Death usually occurs in the sixth or seventh decade and is often due to unrelated causes. Plasma cholesterol levels are normal or only moderately elevated. The pattern of serum lipids is normal, and only serum cholestanol is significantly increased. Radiological features of the disease are infrequently described in the literature. We report a case of CTX in which magnetic resonance imaging (MRI) was used to image the brain, lumbar spine and the tendinous xanthomas of the lower limbs. 15 refs., 5 figs.

  15. Computed tomography and magnetic resonance findings in lipoid pneumonia.

    OpenAIRE

    Bréchot, J M; Buy, J N; Laaban, J P; Rochemaure, J

    1991-01-01

    A case of exogenous lipoid pneumonia was documented by computed tomography and magnetic resonance imaging. Although strongly suggesting the presence of fat on T1 weighted images, magnetic resonance does not produce images specific for this condition. Computed tomography is the best imaging modality for its diagnosis.

  16. Magnetic resonance imaging of the saccular otolithic mass.

    OpenAIRE

    Sbarbati, A; Leclercq, F; Antonakis, K; Osculati, F.

    1992-01-01

    The frog's inner ear was studied in vivo by high spatial resolution magnetic resonance imaging at 7 Tesla. The vestibule, the internal acoustic meatus, and the auditory tube have been identified. The large otolithic mass contained in the vestibule showed a virtual absence of magnetic resonance signal probably due to its composition of closely packed otoconia.

  17. Parametric resonance in vircator with applied magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Grigoryev, V.P.; Koval, T.V. [Inst. of Nuclear Physics, Tomsk (Russian Federation)

    1995-11-01

    The investigation of electromagnetic oscillations excitation in the vircator with an external magnetic field is carried out. The conditions of producing of cyclotron wave parametric resonance with virtual cathode oscillations harmonics have been obtained where the radiation power resonance character depends on the magnetic field value.

  18. Rotating-frame gradient fields for magnetic resonance imaging and nuclear magnetic resonance in low fields

    Science.gov (United States)

    Bouchard, Louis-Serge; Pines, Alexander; Demas, Vasiliki

    2014-01-21

    A system and method for Fourier encoding a nuclear magnetic resonance (NMR) signal is disclosed. A static magnetic field B.sub.0 is provided along a first direction. An NMR signal from the sample is Fourier encoded by applying a rotating-frame gradient field B.sub.G superimposed on the B.sub.0, where the B.sub.G comprises a vector component rotating in a plane perpendicular to the first direction at an angular frequency .omega.in a laboratory frame. The Fourier-encoded NMR signal is detected.

  19. Compact electrically detected magnetic resonance setup

    International Nuclear Information System (INIS)

    Electrically detected magnetic resonance (EDMR) is a commonly used technique for the study of spin-dependent transport processes in semiconductor materials and electro-optical devices. Here, we present the design and implementation of a compact setup to measure EDMR, which is based on a commercially available benchtop electron paramagnetic resonance (EPR) spectrometer. The electrical detection part uses mostly off-the-shelf electrical components and is thus highly customizable. We present a characterization and calibration procedure for the instrument that allowed us to quantitatively reproduce results obtained on a silicon-based reference sample with a “large-scale” state-of-the-art instrument. This shows that EDMR can be used in novel contexts relevant for semiconductor device fabrication like clean room environments and even glove boxes. As an application example, we present data on a class of environment-sensitive objects new to EDMR, semiconducting organic microcrystals, and discuss similarities and differences to data obtained for thin-film devices of the same molecule

  20. Magnetic resonance imaging in clinically-definite multiple sclerosis

    International Nuclear Information System (INIS)

    Forty-two patients with clinically-definite multiple sclerosis were examined by magnetic resonance imaging using a 1.5-T instrument. Magnetic resonance imaging detected an abnormality in 90% of patients. In four patients, no lesions were demonstrated. The number, size and site of the lesions by magnetic resonance imaging were compared with the patients' clinical status and other variables. The Kurtzke disability status scale score increased in patients with corpus callosum atrophy, brainstem and basal ganglia lesions, and correlated with the total number of lesions. No correlation was shown between the findings of magnetic resonance imaging and disease duration, age, sex or pattern-reversal visual-evoked potentials. The variety of magnetic resonance images that could be obtained in patients with clinically-definite multiple sclerosis is highlighted. 24 refs., 8 figs., 1 tab

  1. Magnetic resonance spectroscopy as a diagnostic modality for carcinoma thyroid

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Nikhil [Department of Surgery, Maulana Azad Medical College, Lok Nayak Hospital, New Delhi (India)], E-mail: nikhil_ms26@yahoo.co.in; Kakar, Arun K. [Department of Surgery, Maulana Azad Medical College, Lok Nayak Hospital, New Delhi (India); Chowdhury, Veena [Department of Radiodiagnosis, Maulana Azad Medical College, Lok Nayak Hospital, New Delhi (India); Gulati, Praveen [MR Centre, A-23 Green Park, New Delhi (India); Shankar, L. Ravi [Department of Radioiodine Uptake and Imaging, Institute of Nucler Medicine and Allied Sciences (INMAS), Timarpur, New Delhi (India); Vindal, Anubhav [Department of Surgery, Maulana Azad Medical College, Lok Nayak Hospital, New Delhi (India)

    2007-12-15

    Aim: The aim of this study was to observe the findings of magnetic resonance spectroscopy of solitary thyroid nodules and its correlation with histopathology. Materials and methods: In this study, magnetic resonance spectroscopy was carried out on 26 patients having solitary thyroid nodules. Magnetic resonance spectroscopy (MRS) was performed on a 1.5 T super conductive system with gradient strength of 33 mTs. Fine needle aspiration cytology was done after MRS. All 26 patients underwent surgery either because of cytopathologically proven malignancy or because of cosmetic reasons. Findings of magnetic resonance spectroscopy were compared with histopathology of thyroid specimens. Results and conclusion: It was seen that presence or absence of choline peak correlates very well with presence or absence of malignant foci with in the nodule (sensitivity = 100%; specificity = 88.88%). These results indicate that magnetic resonance spectroscopy may prove to be an useful diagnostic modality for carcinoma thyroid.

  2. Travelling Wave Magnetic Resonance Imaging at 3 Tesla

    OpenAIRE

    Vazquez, F; Martin, R.; Marrufo, O.; Rodriguez, A. O.

    2013-01-01

    Waveguides have been successfully used to generate magnetic resonance images at 7 T with whole-body systems. The bore limits the magnetic resonance signal transmitted because its specific cut-off frequency is greater than the majority of resonant frequencies. This restriction can be overcome by using a parallel-plate waveguide whose cut-off frequency is zero for the transversal electric modes and it can propagate any frequency. To investigate the potential benefits for whole-body imaging at 3...

  3. Electric and magnetic dipole couplings in split ring resonator metamaterials

    Institute of Scientific and Technical Information of China (English)

    Fan Jing; Sun Guang-Yong; and Zhu Wei-Ren

    2011-01-01

    In this paper,the electric and the magnetic dipole couplings between the outer and the inner rings of a single split ring resonator (SRR) are investigated.We numerically demonstrate that the magnetic resonance frequency can be substantially modified by changing the couplings of the electric and magnetic dipoles,and give a theoretical expression of the magnetic resonance frequency.The results in this work are expected to be conducive to a deeper understanding of the SRR and other similar metamaterials,and provide new guidance for complex metamaterials design with a tailored electromagnetic response.

  4. Characterization of human breast disease using phosphorus magnetic resonance spectroscopy and proton magnetic resonance imaging

    International Nuclear Information System (INIS)

    This thesis provides the fundamental characterization and differentiation of breast tissues using in vivo and ex vivo MR techniques in the hope that these techniques and experimental findings will be used on a larger scale and in a predictive manner in order to improve the specificity of diagnosis and treatment of breast cancer. In this dissertation, clinical studies were performed using proton magnetic resonance imaging and phosphorus magnetic resonance spectro-scopy (31P MRS) to characterize and differentiate malignant breast tumors, benign breast tumors and normal breast tissues in vivo. These studies were carried out following the methodical characterization of chemical extracts of malignant breast tumor, benign breast tumor and normal breast parenchymal surgical tissue specimens using high resolution 31P MRS. Alterations in breast tissue metabolism, as a result of pathological processes, were postulated to be responsible for measurable differences between malignant breast tumors, benign breast tumors and normal breast tissues using magnetic resonance techniques. (author). 365 refs.; 37 figs.; 25 tabs

  5. Experiments in Nuclear Magnetic Resonance Microscopy

    Science.gov (United States)

    Lee, Yong; Lu, Wei; Choi, J.-H.; Chia, H. J.; Mirsaidov, U. M.; Guchhait, S.; Cambou, A. D.; Cardenas, R.; Park, K.; Markert, J. T.

    2006-03-01

    We report our group's effort in the construction of an 8-T, ^3 He cryostat based nuclear magnetic resonance force microscope (NMRFM). The probe has two independent 3-D of piezoelectric x-y-z positioners for precise positioning of a fiber optic interferometer and a sample/gradient-producing magnet with respect to a micro-cantilever. The piezoelectric positioners have a very uniform controllable step size with virtually no backlash. A novel RF tuning circuit board design is implemented which allows us to simply swap out one RF component board with another for experiments involving different nuclear species. We successfully fabricated and are characterizing 50μm x50μm x0.2μm double torsional oscillators. We have also been characterizing ultrasoft cantilevers whose spring constant is on the order of 10-4 N/m. We also report NMRFM data for ammonium dihydrogen phosphate(ADP) at room temperature using our 1.2-T system. Observed features include the correct shift of the NMR peak with carrier frequency, increases in signal amplitude with both RF field strength and frequency modulation amplitude, and signal oscillation (spin nutation) as a function of tipping RF pulse length. Experiments in progress on NH4MgF3 (at 1.2 T) and MgB2 (at 8.1 T) will also be briefly reviewed. Robert A. Welch Foundation grant No.F-1191 and the National Science Foundation grant No. DMR-0210383.

  6. Italian registry of cardiac magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Francone, Marco [Department of Radiological, Oncological and Pathological Sciences, Sapienza University of Rome (Italy); Di Cesare, Ernesto, E-mail: ernesto.dicesare@cc.univaq.it [Dipartimento di Scienze Cliniche Applicate e Biotecnologie, Università di L’Aquila (Italy); Cademartiri, Filippo [Cardio-Vascular Imaging Unit, Giovanni XXIII Hospital, Monastier di Treviso, TV (Italy); Erasmus Medical Center University, Rotterdam (Netherlands); Pontone, Gianluca [IRCCS Centro Cardiologico Monzino (Italy); Lovato, Luigi [Policlinico S. Orsola Bologna (Italy); Matta, Gildo [Azienda ospedaliera G Brotzu Cagliari (Italy); Secchi, Francesco [IRCCS Policlinico San Donato, Radiology Unit, Milan (Italy); Maffei, Erica [Cardio-Vascular Imaging Unit, Giovanni XXIII Hospital, Monastier di Treviso, TV (Italy); Erasmus Medical Center University, Rotterdam (Netherlands); Pradella, Silvia [Azienda Ospedaliera Universitaria Careggi (Italy); Carbone, Iacopo [Department of Radiological, Oncological and Pathological Sciences, Sapienza University of Rome (Italy); Marano, Riccardo [Policlinico Gemelli, Università Cattolica Roma (Italy); Bacigalupo, Lorenzo [Ospedale Galliera, Genova (Italy); Chiodi, Elisabetta [Ospedale S. Anna Ferrara (Italy); Donato, Rocco [Azienda Ospedaliera Universitaria G. Martino, Me (Italy); Sbarbati, Stefano [Ospedale Madre Giuseppina Vannini, Roma (Italy); De Cobelli, Francesco [IRCCS S. Raffaele, Università Vita Salute, Milano (Italy); Di Renzi, Paolo [Fate Bene Fratelli Isola tiberina, Roma (Italy); Ligabue, Guido; Mancini, Andrea [Azienda Ospedaliera-Universitaria Policlinico di Modena (Italy); Palmieri, Francesco [Diparimento di Diagnostica per immagini e radiologia interventistica, Ospedale S. Maria delle Grazie, Pozzuoli, Napoli (Italy); and others

    2014-01-15

    Objectives: Forty sites were involved in this multicenter and multivendor registry, which sought to evaluate indications, spectrum of protocols, impact on clinical decision making and safety profile of cardiac magnetic resonance (CMR). Materials and methods: Data were prospectively collected on a 6-month period and included 3376 patients (47.2 ± 19 years; range 1–92 years). Recruited centers were asked to complete a preliminary general report followed by a single form/patient. Referral physicians were not required to exhibit any specific certificate of competency in CMR imaging. Results: Exams were performed with 1.5 T scanners in 96% of cases followed by 3 T (3%) and 1 T (1%) magnets and contrast was administered in 84% of cases. The majority of cases were performed for the workup of inflammatory heart disease/cardiomyopathies representing overall 55.7% of exams followed by the assessment of myocardial viability and acute infarction (respectively 6.9% and 5.9% of patients). In 49% of cases the final diagnosis provided was considered relevant and with impact on patient's clinical/therapeutic management. Safety evaluation revealed 30 (0.88%) clinical events, most of which due to patient's preexisting conditions. Radiological reporting was recorded in 73% of exams. Conclusions: CMR is performed in a large number of centers in Italy with relevant impact on clinical decision making and high safety profile.

  7. Quantitative perfusion imaging in magnetic resonance imaging

    International Nuclear Information System (INIS)

    Magnetic resonance imaging (MRI) is recognized for its superior tissue contrast while being non-invasive and free of ionizing radiation. Due to the development of new scanner hardware and fast imaging techniques during the last decades, access to tissue and organ functions became possible. One of these functional imaging techniques is perfusion imaging with which tissue perfusion and capillary permeability can be determined from dynamic imaging data. Perfusion imaging by MRI can be performed by two approaches, arterial spin labeling (ASL) and dynamic contrast-enhanced (DCE) MRI. While the first method uses magnetically labelled water protons in arterial blood as an endogenous tracer, the latter involves the injection of a contrast agent, usually gadolinium (Gd), as a tracer for calculating hemodynamic parameters. Studies have demonstrated the potential of perfusion MRI for diagnostics and also for therapy monitoring. The utilization and application of perfusion MRI are still restricted to specialized centers, such as university hospitals. A broad application of the technique has not yet been implemented. The MRI perfusion technique is a valuable tool that might come broadly available after implementation of standards on European and international levels. Such efforts are being promoted by the respective professional bodies. (orig.)

  8. Clinical application of functional magnetic resonance imaging

    International Nuclear Information System (INIS)

    The work described in this thesis was carried out at the Magnetic Resonance Centre of the University of Nottingham during the time from May 1998 to April 2001, and is the work of the author except where indicated by reference. The main source of signal changes in functional magnetic resonance imaging (fMRJ) is the fluctuation of paramagnetic deoxyhaemoglobin in the venous blood during different states of functional performance. For the work of this thesis, fMRI studies were carried out using a 3 T MR system with an echo planar imaging (EPI) pulse sequence. Hearing research utilising fMRI has been previously reported in normal subjects. Hearing fMRI is normally performed by stimulating the auditory cortex via an acoustic task presentation such as music, tone, etc. However, performing the same research on deaf subjects requires special equipment to be designed to allow direct stimulation of the auditory nerve. In this thesis, a new method of direct electrical stimulation of the auditory nerve is described that uses a transtympanic electrode implanted onto the surface of the cochlea. This approach would however, result in electromotive forces (EMFs) being induced by the time varying magnetic field, which would lead to current flow and heating, as well as deflection of the metallic electrode within the static magnetic field, and image distortion due to the magnetic susceptibility difference. A gold-plated tungsten electrode with a zero magnetic susceptibility was developed to avoid image distortion. Used with carbon leads and a carbon reference pad, it enabled safe, distortion-free fMRI studies of deaf subjects. The study revealed activation of the primary auditory cortex. This fMRI procedure can be used to demonstrate whether the auditory pathway is fully intact, and may provide a useful method for pre-operative assessment of candidates for cochlear implantation. Glucose is the energy source on which the function of the human brain is entirely dependent. Failure to

  9. Clinical application of functional magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Alwatban, Adnan Z.W

    2002-07-01

    The work described in this thesis was carried out at the Magnetic Resonance Centre of the University of Nottingham during the time from May 1998 to April 2001, and is the work of the author except where indicated by reference. The main source of signal changes in functional magnetic resonance imaging (fMRJ) is the fluctuation of paramagnetic deoxyhaemoglobin in the venous blood during different states of functional performance. For the work of this thesis, fMRI studies were carried out using a 3 T MR system with an echo planar imaging (EPI) pulse sequence. Hearing research utilising fMRI has been previously reported in normal subjects. Hearing fMRI is normally performed by stimulating the auditory cortex via an acoustic task presentation such as music, tone, etc. However, performing the same research on deaf subjects requires special equipment to be designed to allow direct stimulation of the auditory nerve. In this thesis, a new method of direct electrical stimulation of the auditory nerve is described that uses a transtympanic electrode implanted onto the surface of the cochlea. This approach would however, result in electromotive forces (EMFs) being induced by the time varying magnetic field, which would lead to current flow and heating, as well as deflection of the metallic electrode within the static magnetic field, and image distortion due to the magnetic susceptibility difference. A gold-plated tungsten electrode with a zero magnetic susceptibility was developed to avoid image distortion. Used with carbon leads and a carbon reference pad, it enabled safe, distortion-free fMRI studies of deaf subjects. The study revealed activation of the primary auditory cortex. This fMRI procedure can be used to demonstrate whether the auditory pathway is fully intact, and may provide a useful method for pre-operative assessment of candidates for cochlear implantation. Glucose is the energy source on which the function of the human brain is entirely dependent. Failure to

  10. Controlling interactions between highly-magnetic atoms with Feshbach resonances

    CERN Document Server

    Kotochigova, Svetlana

    2014-01-01

    This paper reviews current experimental and theoretical progress in the study of dipolar quantum gases of ground and meta-stable atoms with a large magnetic moment. We emphasize the anisotropic nature of Feshbach resonances due to coupling to fast-rotating resonant molecular states in ultracold s-wave collisions between magnetic atoms in external magnetic fields. The dramatic differences in the distribution of resonances of magnetic $^7$S$_3$ chromium and magnetic lanthanide atoms with a submerged 4f shell and non-zero electron angular momentum is analyzed. We focus on Dysprosium and Erbium as important experimental advances have been recently made to cool and create quantum-degenerate gases for these atoms. Finally, we describe progress in locating resonances in collisions of meta-stable magnetic atoms in electronic P states with ground-state atoms, where an interplay between collisional anisotropies and spin-orbit coupling exists.

  11. Evaporation residue excitation function measurement for 19F + 194,198Pt reactions

    International Nuclear Information System (INIS)

    Nuclear dissipation is one of the active fields in the present day nuclear physics research. Experimental signatures for dissipation are observed through large excess in pre-fission neutrons, γ-ray multiplicities from the compound nucleus, giant dipole resonance (GDR) γ-rays, light charged particles and evaporation residues in comparison to standard statistical model, for the heavy-ion induced fusion-fission or fusion-evaporation reactions (ERs). From the analysis of a large set of experimental data, it is well established that there exists a large dissipation at nuclear temperature above 1 MeV. But most of these probes are not sensitive to the dissipation within saddle. The ER cross-section is a probe which is sensitive to dissipation within the saddle point. Hence, the study of ER cross-section can be helpful in estimating the dissipation effects inside the saddle point. Also the other motivation for these measurements is to see the effect of shell closure on dissipation. With this motivation the evaporation cross-sections for 19F + 194,198Pt are measured at beam energy of 101 to 137.3 MeV. Of the above systems 19F + 194Pt populates 213Fr (N = 126) shell closed compound nucleus (CN) whereas, other system populate 217Fr (N = 130) non-shell closed CN

  12. Resonant modes of vortex structures in soft-magnetic nanodiscs

    International Nuclear Information System (INIS)

    We present micromagnetic finite-element simulations on the dynamic response of a soft-magnetic disc exposed to an oscillatory field applied in the disc plane. The disc is magnetized in a vortex state. At lower frequencies (about 200 MHz in our example) we find a motion of the vortex core on an elliptical orbit as a resonant mode. At higher frequencies, the out-of-plane component of the magnetization becomes resonant by the excitation of standing magnetostatic waves

  13. Statistical Analysis Of Tank 19F Floor Sample Results

    International Nuclear Information System (INIS)

    Representative sampling has been completed for characterization of the residual material on the floor of Tank 19F as per the statistical sampling plan developed by Harris and Shine. Samples from eight locations have been obtained from the tank floor and two of the samples were archived as a contingency. Six samples, referred to in this report as the current scrape samples, have been submitted to and analyzed by SRNL. This report contains the statistical analysis of the floor sample analytical results to determine if further data are needed to reduce uncertainty. Included are comparisons with the prior Mantis samples results to determine if they can be pooled with the current scrape samples to estimate the upper 95% confidence limits (UCL95%) for concentration. Statistical analysis revealed that the Mantis and current scrape sample results are not compatible. Therefore, the Mantis sample results were not used to support the quantification of analytes in the residual material. Significant spatial variability among the current scrape sample results was not found. Constituent concentrations were similar between the North and South hemispheres as well as between the inner and outer regions of the tank floor. The current scrape sample results from all six samples fall within their 3-sigma limits. In view of the results from numerous statistical tests, the data were pooled from all six current scrape samples. As such, an adequate sample size was provided for quantification of the residual material on the floor of Tank 19F. The uncertainty is quantified in this report by an UCL95% on each analyte concentration. The uncertainty in analyte concentration was calculated as a function of the number of samples, the average, and the standard deviation of the analytical results. The UCL95% was based entirely on the six current scrape sample results (each averaged across three analytical determinations).

  14. Quantifying mixing using magnetic resonance imaging.

    Science.gov (United States)

    Tozzi, Emilio J; McCarthy, Kathryn L; Bacca, Lori A; Hartt, William H; McCarthy, Michael J

    2012-01-25

    Mixing is a unit operation that combines two or more components into a homogeneous mixture. This work involves mixing two viscous liquid streams using an in-line static mixer. The mixer is a split-and-recombine design that employs shear and extensional flow to increase the interfacial contact between the components. A prototype split-and-recombine (SAR) mixer was constructed by aligning a series of thin laser-cut Poly (methyl methacrylate) (PMMA) plates held in place in a PVC pipe. Mixing in this device is illustrated in the photograph in Fig. 1. Red dye was added to a portion of the test fluid and used as the minor component being mixed into the major (undyed) component. At the inlet of the mixer, the injected layer of tracer fluid is split into two layers as it flows through the mixing section. On each subsequent mixing section, the number of horizontal layers is duplicated. Ultimately, the single stream of dye is uniformly dispersed throughout the cross section of the device. Using a non-Newtonian test fluid of 0.2% Carbopol and a doped tracer fluid of similar composition, mixing in the unit is visualized using magnetic resonance imaging (MRI). MRI is a very powerful experimental probe of molecular chemical and physical environment as well as sample structure on the length scales from microns to centimeters. This sensitivity has resulted in broad application of these techniques to characterize physical, chemical and/or biological properties of materials ranging from humans to foods to porous media (1, 2). The equipment and conditions used here are suitable for imaging liquids containing substantial amounts of NMR mobile (1)H such as ordinary water and organic liquids including oils. Traditionally MRI has utilized super conducting magnets which are not suitable for industrial environments and not portable within a laboratory (Fig. 2). Recent advances in magnet technology have permitted the construction of large volume industrially compatible magnets suitable for

  15. Quantifying mixing using magnetic resonance imaging.

    Science.gov (United States)

    Tozzi, Emilio J; McCarthy, Kathryn L; Bacca, Lori A; Hartt, William H; McCarthy, Michael J

    2012-01-01

    Mixing is a unit operation that combines two or more components into a homogeneous mixture. This work involves mixing two viscous liquid streams using an in-line static mixer. The mixer is a split-and-recombine design that employs shear and extensional flow to increase the interfacial contact between the components. A prototype split-and-recombine (SAR) mixer was constructed by aligning a series of thin laser-cut Poly (methyl methacrylate) (PMMA) plates held in place in a PVC pipe. Mixing in this device is illustrated in the photograph in Fig. 1. Red dye was added to a portion of the test fluid and used as the minor component being mixed into the major (undyed) component. At the inlet of the mixer, the injected layer of tracer fluid is split into two layers as it flows through the mixing section. On each subsequent mixing section, the number of horizontal layers is duplicated. Ultimately, the single stream of dye is uniformly dispersed throughout the cross section of the device. Using a non-Newtonian test fluid of 0.2% Carbopol and a doped tracer fluid of similar composition, mixing in the unit is visualized using magnetic resonance imaging (MRI). MRI is a very powerful experimental probe of molecular chemical and physical environment as well as sample structure on the length scales from microns to centimeters. This sensitivity has resulted in broad application of these techniques to characterize physical, chemical and/or biological properties of materials ranging from humans to foods to porous media (1, 2). The equipment and conditions used here are suitable for imaging liquids containing substantial amounts of NMR mobile (1)H such as ordinary water and organic liquids including oils. Traditionally MRI has utilized super conducting magnets which are not suitable for industrial environments and not portable within a laboratory (Fig. 2). Recent advances in magnet technology have permitted the construction of large volume industrially compatible magnets suitable for

  16. Non-resonant magnetic braking on JET and TEXTOR

    DEFF Research Database (Denmark)

    Sun, Y.; Liang, Y.; Shaing, K.C.;

    2012-01-01

    The non-resonant magnetic braking effect induced by a non-axisymmetric magnetic perturbation is investigated on JET and TEXTOR. The collisionality dependence of the torque induced by the n = 1, where n is the toroidal mode number, magnetic perturbation generated by the error field correction coil...

  17. Resonant Mode Reduction in Radiofrequency Volume Coils for Ultrahigh Field Magnetic Resonance Imaging

    OpenAIRE

    Xiaoliang Zhang; Daniel Vigneron; Ye Li; Duan Xu; Yong Pang; Zhentian Xie

    2011-01-01

    In a multimodal volume coil, only one mode can generate homogeneous Radiofrequency (RF) field for Magnetic Resonance Imaging. The existence of other modes may increase the volume coil design difficulties and potentially decreases coil performance. In this study, we introduce common-mode resonator technique to high and ultrahigh field volume coil designs to reduce the resonant mode while maintain the homogeneity of the RF field. To investigate the design method, the common-mode resonator was r...

  18. Advances in cardiac magnetic resonance imaging of congenital heart disease

    Energy Technology Data Exchange (ETDEWEB)

    Driessen, Mieke M.P. [University of Utrecht, University Medical Center Utrecht, Department of Radiology, PO Box 85500, Utrecht (Netherlands); University of Utrecht, University Medical Center Utrecht, Department of Cardiology, PO Box 85500, Utrecht (Netherlands); The Interuniversity Cardiology Institute of the Netherlands (ICIN) - Netherlands Heart Institute, PO Box 19258, Utrecht (Netherlands); Breur, Johannes M.P.J. [Wilhelmina Children' s Hospital, University Medical Center Utrecht, Department of Pediatric Cardiology, PO Box 85500, Utrecht (Netherlands); Budde, Ricardo P.J.; Oorschot, Joep W.M. van; Leiner, Tim [University of Utrecht, University Medical Center Utrecht, Department of Radiology, PO Box 85500, Utrecht (Netherlands); Kimmenade, Roland R.J. van; Sieswerda, Gertjan Tj [University of Utrecht, University Medical Center Utrecht, Department of Cardiology, PO Box 85500, Utrecht (Netherlands); Meijboom, Folkert J. [University of Utrecht, University Medical Center Utrecht, Department of Cardiology, PO Box 85500, Utrecht (Netherlands); Wilhelmina Children' s Hospital, University Medical Center Utrecht, Department of Pediatric Cardiology, PO Box 85500, Utrecht (Netherlands)

    2015-01-01

    Due to advances in cardiac surgery, survival of patients with congenital heart disease has increased considerably during the past decades. Many of these patients require repeated cardiovascular magnetic resonance imaging to assess cardiac anatomy and function. In the past decade, technological advances have enabled faster and more robust cardiovascular magnetic resonance with improved image quality and spatial as well as temporal resolution. This review aims to provide an overview of advances in cardiovascular magnetic resonance hardware and acquisition techniques relevant to both pediatric and adult patients with congenital heart disease and discusses the techniques used to assess function, anatomy, flow and tissue characterization. (orig.)

  19. Science Drivers and Technical Challenges for Advanced Magnetic Resonance

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Karl T.; Pruski, Marek; Washton, Nancy M.; Lipton, Andrew S.

    2013-03-07

    This report recaps the "Science Drivers and Technical Challenges for Advanced Magnetic Resonance" workshop, held in late 2011. This exploratory workshop's goal was to discuss and address challenges for the next generation of magnetic resonance experimentation. During the workshop, participants from throughout the world outlined the science drivers and instrumentation demands for high-field dynamic nuclear polarization (DNP) and associated magnetic resonance techniques, discussed barriers to their advancement, and deliberated the path forward for significant and impactful advances in the field.

  20. Magnetic resonance imaging of a brain abscess

    International Nuclear Information System (INIS)

    Magnetic resonance imaging (MRI) was performed on 13 patients with brain abscesses, and the alternation of MRI findings, as correlated with the progression of brain-abscess formation, was reviewed. In the cerebritis stage, spin-echo images showed a high intensity, and inversion-recovery images, a low intensity, due to inflammation and edema. The spin-echo images were very sensitive in delineating the brain edema; however, it was difficult to distinguish the inflammation from the surrounding edema. In the capsule stage, due to the accumulation of purulent material, the central necrotic area was demonstrated as a low-intensity area, while the capsule of the abscess was revealed as an iso-intensity ring on the inversion-recovery images. The central necrotic area also decreased in intensity on spin-echo images in the later period of this stage. With contrast enhancement (Gd-DTPA), the SR image showed the capsule as a high-intensity ring. MRI was found to be a useful method for estimating the process of the formation of a brain abscess. (author)

  1. Magnetic resonance imaging of a brain abscess

    Energy Technology Data Exchange (ETDEWEB)

    Oikawa, Akihiro; Kagawa, Mizuo; Yatoh, Seiji; Izawa, Masahiro; Ujiie, Hiroshi; Sakaguchi, Jun; Onda, Hideaki; Kitamura, Kohichi

    1988-06-01

    Magnetic resonance imaging (MRI) was performed on 13 patients with brain abscesses, and the alternation of MRI findings, as correlated with the progression of brain-abscess formation, was reviewed. In the cerebritis stage, spin-echo images showed a high intensity, and inversion-recovery images, a low intensity, due to inflammation and edema. The spin-echo images were very sensitive in delineating the brain edema; however, it was difficult to distinguish the inflammation from the surrounding edema. In the capsule stage, due to the accumulation of purulent material, the central necrotic area was demonstrated as a low-intensity area, while the capsule of the abscess was revealed as an iso-intensity ring on the inversion-recovery images. The central necrotic area also decreased in intensity on spin-echo images in the later period of this stage. With contrast enhancement (Gd-DTPA), the SR image showed the capsule as a high-intensity ring. MRI was found to be a useful method for estimating the process of the formation of a brain abscess.

  2. Magnetic resonance imaging of cystic periventricular leukomalacia

    Energy Technology Data Exchange (ETDEWEB)

    Kadoi, Nobuaki; Nomura, Junko; Nowatari, Masahiko; Ohta, Takeo; Kamohara, Takashi; Yashiro, Kimio (Kitasato Univ., Sagamihara, Kanagawa (Japan). School of Medicine)

    1990-08-01

    A study was performed to assess the values of magnetic resonance (MR) imaging in evaluation and the follow up of patients with cystic periventricular leukomalacia. Ten patients selected for MR imaging were diagnosed as having periventricular cystic lesions based on US scans. The range of gestational ages was 27 to 32 weeks, and the range of birth weights was 927 to 2,046 g. Twenty MR examinations were carried out using a 0.5 T superconducting system (Resona; Yokogawa). On the first MR examinations, taken by 6 months of age, low signal intensity lesions within the periventricular white matter, moderate ventriculomegaly with irregularity of the ventricular wall and delayed myelination were observed. These were the MR findings observed in the subacute stage of PVL. On the second or the third MR examinations, taken after 12 months of age, increased signal intensity in periventricular white matter on T{sub 2} weighted images decreased volume of periventricular white matter and centrum semiovale and the ventriculomagaly with irregularity of ventricular wall were observed. However, progressions of myelination were proved to be not delayed in comparison with age matched controls. These were thought to be the MR findings of late stage of PVL. As the US findings of PVL have good correlation with pathologic changes revealed at autopsy, MR imaging can depict myelination and detect PVL lesion beyond the neonatal period. These observations demonstrate the value of the MR imaging for the follow up of the patients with PVL beyond the time of fontanel closure. (author).

  3. Magnetic resonance perfusion imaging without contrast media

    Energy Technology Data Exchange (ETDEWEB)

    Martirosian, Petros; Graf, Hansjoerg; Schick, Fritz [University Hospital of Tuebingen, Section on Experimental Radiology, Tuebingen (Germany); Boss, Andreas; Schraml, Christina; Schwenzer, Nina F.; Claussen, Claus D. [University Hospital of Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany)

    2010-08-15

    Principles of magnetic resonance imaging techniques providing perfusion-related contrast weighting without administration of contrast media are reported and analysed systematically. Especially common approaches to arterial spin labelling (ASL) perfusion imaging allowing quantitative assessment of specific perfusion rates are described in detail. The potential of ASL for perfusion imaging was tested in several types of tissue. After a systematic comparison of technical aspects of continuous and pulsed ASL techniques the standard kinetic model and tissue properties of influence to quantitative measurements of perfusion are reported. For the applications demonstrated in this paper a flow-sensitive alternating inversion recovery (FAIR) ASL perfusion preparation approach followed by true fast imaging with steady precession (true FISP) data recording was developed and implemented on whole-body scanners operating at 0.2, 1.5 and 3 T for quantitative perfusion measurement in various types of tissue. ASL imaging provides a non-invasive tool for assessment of tissue perfusion rates in vivo. Images recorded from kidney, lung, brain, salivary gland and thyroid gland provide a spatial resolution of a few millimetres and sufficient signal to noise ratio in perfusion maps after 2-5 min of examination time. Newly developed ASL techniques provide especially high image quality and quantitative perfusion maps in tissues with relatively high perfusion rates (as also present in many tumours). Averaging of acquisitions and image subtraction procedures are mandatory, leading to the necessity of synchronization of data recording to breathing in abdominal and thoracic organs. (orig.)

  4. Exploring brain function with magnetic resonance imaging

    International Nuclear Information System (INIS)

    Since its invention in the early 1990s, functional magnetic resonance imaging (fMRI) has rapidly assumed a leading role among the techniques used to localize brain activity. The spatial and temporal resolution provided by state-of-the-art MR technology and its non-invasive character, which allows multiple studies of the same subject, are some of the main advantages of fMRI over the other functional neuroimaging modalities that are based on changes in blood flow and cortical metabolism. This paper describes the basic principles and methodology of fMRI and some aspects of its application to functional activation studies. Attention is focused on the physiology of the blood oxygenation level-dependent (BOLD) contrast mechanism and on the acquisition of functional time-series with echo planar imaging (EPI). We also provide an introduction to the current strategies for the correction of signal artefacts and other image processing techniques. In order to convey an idea of the numerous applications of fMRI, we will review some of the recent results in the fields of cognitive and sensorimotor psychology and physiology

  5. Magnetic Resonance Imaging Features of Neuromyelitis Optica

    Energy Technology Data Exchange (ETDEWEB)

    You, Sun Kyung; Song, Chang June; Park, Woon Ju; Lee, In Ho; Son, Eun Hee [Chungnam National University College of Medicine, Chungnam National University Hospital, Daejeon (Korea, Republic of)

    2013-03-15

    To report the magnetic resonance (MR) imaging features of the spinal cord and brain in patients of neuromyelitis optica (NMO). Between January 2001 and March 2010, the MR images (spinal cord, brain, and orbit) and the clinical and serologic findings of 11 NMO patients were retrospectively reviewed. The contrast-enhancement of the spinal cord was performed (20/23). The presence and pattern of the contrast-enhancement in the spinal cord were classified into 5 types. Acute myelitis was monophasic in 8 patients (8/11, 72.7%); and optic neuritis preceded acute myelitis in most patients. Longitudinally extensive cord lesion (average, 7.3 vertebral segments) was involved. The most common type was the diffuse and subtle enhancement of the spinal cord with a multifocal nodular, linear or segmental intense enhancement (45%). Most of the brain lesions (5/11, 10 lesions) were located in the brain stem, thalamus and callososeptal interphase. Anti-Ro autoantibody was positive in 2 patients, and they showed a high relapse rate of acute myelitis. Anti-NMO IgG was positive in 4 patients (4/7, 66.7%). The imaging findings of acute myelitis in NMO may helpful in making an early diagnosis of NMO which can result in a severe damage to the spinal cord, and to make a differential diagnosis of multiple sclerosis and inflammatory diseases of the spinal cord such as toxocariasis.

  6. Magnetic resonance imaging of primary vaginal carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, M.B. [Department of Diagnostic Radiology, Christie Hospital NHS Trust, Withington, Manchester (United Kingdom)]. E-mail: ben.taylor@christie-tr.nwest.nhs.uk; Dugar, N. [Department of Diagnostic Radiology, Christie Hospital NHS Trust, Withington, Manchester (United Kingdom); Davidson, S.E. [Radiation Oncology, Christie Hospital NHS Trust, Withington, Manchester (United Kingdom); Carrington, B.M. [Department of Diagnostic Radiology, Christie Hospital NHS Trust, Withington, Manchester (United Kingdom)

    2007-06-15

    Aims: To describe the magnetic resonance imaging (MRI) features of vaginal carcinoma and to suggest a role for MRI in its management. Materials and methods: Twenty-five patients with primary vaginal carcinoma treated at our institution between 1996 and 2005 were included in the study. The MRI examinations were reviewed and tumour dimensions, signal characteristics and involvement of pelvic structures were documented, as were sites of enlarged lymph nodes and metastases. Details of patient treatment and outcome were obtained from the clinical notes. Results: The median patient age was 54 years (range 31-86 years). Tumour maximum diameter ranged from 1.6-11.3 cm (mean 3.7 cm). Most tumours were of iso-intense signal to muscle on T1-weighted images and hyper-intense to muscle on T2-weighted images. Eighty-eight percent of patients had tumour extending beyond the vagina and 56% of patients had Figo stage III or above tumours. Sixteen patients were treated with radiotherapy (two with chemoradiotherapy), five with surgery and four with supportive care. Ten patients (40%) died of their disease during the study period. The MRI stage of the tumour correlated with survival. Conclusion: MRI identified over 95% of primary vaginal tumours in the present study, enabled radiological staging, which correlated with outcome, and provided information of use in treatment planning.

  7. Magnetic resonance imaging structured reporting in infertility.

    Science.gov (United States)

    Montoliu-Fornas, Guillermina; Martí-Bonmatí, Luis

    2016-06-01

    Our objective was to define and propose a standardized magnetic resonance (MR) imaging structured report in patients with infertility to have clinical completeness on possible diagnosis and severity. Patients should be studied preferable on 3T equipment with a surface coil. Standard MR protocol should include high-resolution fast spin-echo T2-weighted, diffusion-weighted images and gradient-echo T1-weighted fat suppression images. The report should include ovaries (polycystic, endometrioma, tumor), oviduct (hydrosalpinx, hematosalpinx, pyosalpinx, peritubal anomalies), uterus (agenesia, hypoplasia, unicornuate, uterus didelphys, bicornuate, septate uterus), myometrium (leiomyomas, adenomyosis), endometrium (polyps, synechia, atrophy, neoplasia), cervix and vagina (isthmoceles, mucosal-parietal irregularity, stenosis, neoplasia), peritoneum (deep endometriosis), and urinary system-associated abnormalities. To be clinically useful, radiology reports must be structured, use standardized terminology, and convey actionable information. The structured report must comprise complete, comprehensive, and accurate information, allowing radiologists to continuously interact with patients and referring physicians to confirm that the information is used properly to affect the decision making process. PMID:27105717

  8. Cardiovascular magnetic resonance in pericardial diseases

    Directory of Open Access Journals (Sweden)

    Francone Marco

    2009-05-01

    Full Text Available Abstract The pericardium and pericardial diseases in particular have received, in contrast to other topics in the field of cardiology, relatively limited interest. Today, despite improved knowledge of pathophysiology of pericardial diseases and the availability of a wide spectrum of diagnostic tools, the diagnostic challenge remains. Not only the clinical presentation may be atypical, mimicking other cardiac, pulmonary or pleural diseases; in developed countries a shift for instance in the epidemiology of constrictive pericarditis has been noted. Accurate decision making is crucial taking into account the significant morbidity and mortality caused by complicated pericardial diseases, and the potential benefit of therapeutic interventions. Imaging herein has an important role, and cardiovascular magnetic resonance (CMR is definitely one of the most versatile modalities to study the pericardium. It fuses excellent anatomic detail and tissue characterization with accurate evaluation of cardiac function and assessment of the haemodynamic consequences of pericardial constraint on cardiac filling. This review focuses on the current state of knowledge how CMR can be used to study the most common pericardial diseases.

  9. Fetal magnetic resonance imaging and ultrasound.

    Science.gov (United States)

    Wataganara, Tuangsit; Ebrashy, Alaa; Aliyu, Labaran Dayyabu; Moreira de Sa, Renato Augusto; Pooh, Ritsuko; Kurjak, Asim; Sen, Cihat; Adra, Abdallah; Stanojevic, Milan

    2016-07-01

    Magnetic resonance imaging (MRI) has been increasingly adopted in obstetrics practice in the past three decades. MRI aids prenatal ultrasound and improves diagnostic accuracy for selected maternal and fetal conditions. However, it should be considered only when high-quality ultrasound cannot provide certain information that affects the counseling, prenatal intervention, pregnancy course, and delivery plan. Major indications of fetal MRI include, but are not restricted to, morbidly adherent placenta, selected cases of fetal brain anomalies, thoracic lesions (especially in severe congenital diaphragmatic hernia), and soft tissue tumors at head and neck regions of the fetus. For fetal anatomy assessment, a 1.5-Tesla machine with a fast T2-weighted single-shot technique is recommended for image requisition of common fetal abnormalities. Individual judgment needs to be applied when considering usage of a 3-Tesla machine. Gadolinium MRI contrast is not recommended during pregnancy. MRI should be avoided in the first half of pregnancy due to small fetal structures and motion artifacts. Assessment of fetal cerebral cortex can be achieved with MRI in the third trimester. MRI is a viable research tool for noninvasive interrogation of the fetus and the placenta. PMID:27092644

  10. Magnetic resonance imaging of the normal placenta

    Energy Technology Data Exchange (ETDEWEB)

    Blaicher, Wibke [Department of Gynecology and Obstetrics, University Hospital Vienna (Austria)]. E-mail: wibke.blaicher@meduniwien.ac.at; Brugger, Peter C. [Center of Anatomy and Cell Biology, University Hospital of Vienna (Austria); Mittermayer, Christoph [Department of Pediatrics, Division of Neonatology and Intensive Care, University Hospital of Vienna (Austria); Schwindt, Jens [Department of Pediatrics, Division of Neonatology and Intensive Care, University Hospital of Vienna (Austria); Deutinger, Josef [Department of Gynecology and Obstetrics, University Hospital Vienna (Austria); Bernaschek, Gerhard [Department of Gynecology and Obstetrics, University Hospital Vienna (Austria); Prayer, Daniela [Department of Radiology, Division of Neuroradiology, University Hospital of Vienna (Austria)

    2006-02-15

    The goal of this study was to provide a representative description of the normal placenta with contrast medium-free magnetic resonance imaging (MRI) in order to determine a standard of reference. One hundred consecutive singleton pregnancies were investigated by MRI without application of a contrast medium. The mean gestational age (GA) at the time of investigation was 29.5 weeks (range 19-40). Patients with suspected utero-placental insufficiency (UPI) or placental anomalies were excluded. Signal intensities were assessed and correlated with the respective GA. Antenatal MRI without contrast medium was able to depict placental status and morphological changes during gestation. A regular homogeneous structure was found in weeks 19-23. Subsequently, sporadic, slightly marked lobules appeared, which increased in number and markedness with ongoing gestation. Stratification of the lobules was observed after 36 weeks. The ratio of placental and amniotic fluid signal intensities decreased significantly with higher GA and with placental grading. MRI is well suited as an imaging method for the placenta. Our data may be used as a reference in the assessment of the placenta on MRI, and may have further clinical impact with respect to the determination of UPI.

  11. Magnetic resonance tomography of the knee joint

    International Nuclear Information System (INIS)

    To compare the diagnostic performance of magnetic resonance imaging (MRI) in terms of sensitivity and specificity using a field strength of <1.0 T (T) versus ≥1.5 T for diagnosing or ruling out knee injuries or knee pathologies. The systematic literature research revealed more than 10,000 references, of which 1598 abstracts were reviewed and 87 full-text articles were retrieved. The further selection process resulted in the inclusion of four systematic reviews and six primary studies. No differences could be identified in the diagnostic performance of low- versus high-field MRI for the detection or exclusion of meniscal or cruciate ligament tears. Regarding the detection or grading of cartilage defects and osteoarthritis of the knee, the existing evidence suggests that high-field MRI is tolerably specific but not very sensitive, while there is literally no evidence for low-field MRI because only a few studies with small sample sizes and equivocal findings have been performed. We can recommend the use of low-field strength MRI systems in suspected meniscal or cruciate ligament injuries. This does, however, not apply to the diagnosis and grading of knee cartilage defects and osteoarthritis because of insufficient evidence. (orig.)

  12. Magnetic resonance tomography of the knee joint

    Energy Technology Data Exchange (ETDEWEB)

    Puig, Stefan; Kuruvilla, Yojena Chittazhathu Kurian; Ebner, Lukas [University Hospital, University of Berne, Department of Interventional, Pediatric and Diagnostic Radiology Inselspital, Berne (Switzerland); Endel, Gottfried [Main Association of Austrian Social Insurance Institutions, Vienna (Austria)

    2015-10-15

    To compare the diagnostic performance of magnetic resonance imaging (MRI) in terms of sensitivity and specificity using a field strength of <1.0 T (T) versus ≥1.5 T for diagnosing or ruling out knee injuries or knee pathologies. The systematic literature research revealed more than 10,000 references, of which 1598 abstracts were reviewed and 87 full-text articles were retrieved. The further selection process resulted in the inclusion of four systematic reviews and six primary studies. No differences could be identified in the diagnostic performance of low- versus high-field MRI for the detection or exclusion of meniscal or cruciate ligament tears. Regarding the detection or grading of cartilage defects and osteoarthritis of the knee, the existing evidence suggests that high-field MRI is tolerably specific but not very sensitive, while there is literally no evidence for low-field MRI because only a few studies with small sample sizes and equivocal findings have been performed. We can recommend the use of low-field strength MRI systems in suspected meniscal or cruciate ligament injuries. This does, however, not apply to the diagnosis and grading of knee cartilage defects and osteoarthritis because of insufficient evidence. (orig.)

  13. Magnetic Resonance Imaging in Pediatric Elbow Fractures

    Energy Technology Data Exchange (ETDEWEB)

    Pudas, T.; Hurme, T.; Mattila, K.; Svedstroem, E. [Univ. of Turku, (Finland). Depts. of Radiology and Pediatric Surgery

    2005-10-01

    Purpose: Magnetic resonance imaging (MRI) evaluation of pediatric elbow trauma with or without a visible fracture on radiography. Material and Methods: MRI was performed in the acute phase in 25 children with an elbow injury. Nine patients with an elbow effusion only on radiographs and 16 with a fracture or luxation seen on radiographs underwent subsequent MRI. No sedation was used. Results: MRI revealed eight occult fractures (89%) in seven out of nine patients who had only an effusion on radiographs. Based on MRI findings, septic arthritis was suspected in one patient. Two patients out of five with a supracondylar fracture on the radiograph had a cartilage lesion in the humerus. MRI depicted a 3-mm gap on the articular surface in two patients with a lateral condyle fracture, a more accurate fracture location in two patients than the radiographs, and an additional occult fracture in two patients. MRI showed a fracture not seen on radiographs in two of three patients with prior luxation. Conclusion: MRI is a sensitive and accurate method in the diagnosis of pediatric elbow injuries, especially when only an effusion is present on radiographs. Occult fractures are more common in pediatric patients with elbow injury than reported earlier.

  14. Pancreatitis: computed tomography and magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, P.J.A.; Sheridan, M.B. [Dept. of Clinical Radiology, St. James' s University Hospital, Leeds (United Kingdom)

    2000-03-01

    The value of CT in management of severe acute pancreatitis is well established. Some, but not all, experimental studies suggest a detrimental effect of intravenous iodinated contrast agents in acute pancreatitis, but although initial clinical data tends to support this, the positive advantages of enhanced CT outweigh the possible risks. Magnetic resonance imaging has been shown to be as effective as CT in demonstrating the presence and extent of pancreatic necrosis and fluid collections, and probably superior in indicating the suitability of such collections for percutaneous drainage. Image-guided intervention remains a key approach in the management of severely ill patients, and the indications, techniques and results of radiological intervention are reviewed herein. Both CT and MRI can be used to diagnose advanced chronic pancreatitis, with the recent addition of MRCP as a viable alternative to diagnostic endoscopic retrograde cholangiopancreatography (ERCP). Both MRCP and CT/MR imaging of the pancreatic parenchyma still have limitations in the recognition of the earliest changes of chronic pancreatitis - for which ERCP and tests of pancreatic function remain more sensitive - but the clinical significance of these minor changes remains contentious. (orig.)

  15. Potts disease: Diagnosis with magnetic resonance imaging

    International Nuclear Information System (INIS)

    The eponymously named Potts disease is a relatively rare form of Tuberculosis (TB) which affects the spine. TB of the spine is one of the earliest diseases known to man and in the 20th century was thought to be a disease which had been defeated by the advent of antitubercular drugs. Over the last two decades there have been several reports which indicate a revival of TB in both the developing and developed world. Factors which may be contributing to this are the spread of the HIV virus, increased immigration and the emergence of drug resistant strains of the TB bacteria. Potts disease has an insidious onset and often the radiographic findings are far advanced when a diagnosis is finally reached. MRI is able to detect changes to the vertebrae in Potts disease earlier than radiographs. This case report outlines the clinical presentation of a young male with Potts disease who was HIV negative, and the important role that MRI plays in diagnosis and therefore in appropriate and timely intervention. The typical magnetic resonance (MR) imaging features and the radiographic hallmarks of the disease will also be discussed.

  16. Neural network segmentation of magnetic resonance images

    Science.gov (United States)

    Frederick, Blaise

    1990-07-01

    Neural networks are well adapted to the task of grouping input patterns into subsets which share some similarity. Moreover once trained they can generalize their classification rules to classify new data sets. Sets of pixel intensities from magnetic resonance (MR) images provide a natural input to a neural network by varying imaging parameters MR images can reflect various independent physical parameters of tissues in their pixel intensities. A neural net can then be trained to classify physically similar tissue types based on sets of pixel intensities resulting from different imaging studies on the same subject. A neural network classifier for image segmentation was implemented on a Sun 4/60 and was tested on the task of classifying tissues of canine head MR images. Four images of a transaxial slice with different imaging sequences were taken as input to the network (three spin-echo images and an inversion recovery image). The training set consisted of 691 representative samples of gray matter white matter cerebrospinal fluid bone and muscle preclassified by a neuroscientist. The network was trained using a fast backpropagation algorithm to derive the decision criteria to classify any location in the image by its pixel intensities and the image was subsequently segmented by the classifier. The classifier''s performance was evaluated as a function of network size number of network layers and length of training. A single layer neural network performed quite well at

  17. Magnetic Resonance Imaging in Pediatric Epilepsy

    Directory of Open Access Journals (Sweden)

    R. Barikbin

    2008-01-01

    Full Text Available Epilepsy is a common neurological affliction of children. It carries an estimated annual incidence of up to one per 1,000, and a prevalence of up to 5 per 1,000 children. Children suffering from epilepsy have a significantly increased mortality rate. The major causes of death are the underlying cause of the epilepsy itself, associated neurological compromise, injuries, and status epilepticus."nNeuroimaging techniques have advanced the diagnosis, management, and understanding the pathophysiology of underlying the epilepsies. MRI is the technique of choice for investigation of patients with seizure disorders. MRI provides excellent anatomic information and tissue contrast, resulting in high sensitivity. MRI studies should be customized to answer the appropriate clinical questions. Functional imaging techniques including magnetic resonance spectroscopy and functional MRI are becoming increasingly important in the investigation and management of patients with seizures. These techniques permit noninvasive assessment of the epileptic substrate, functional status, ictal activity, blood flow changes, me-tabolism, and neuroreceptors. Application of these new techniques promises to advance our understanding and treatment of seizures in children. In this presentation we will address the MR findings of epilepsy in children.

  18. Focal liver lesions: Practical magnetic resonance imagingapproach

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    With the widespread of cross-sectional imaging, a growthof incidentally detected focal liver lesions (FLL) hasbeen observed. A reliable detection and characterizationof FLL is critical for optimal patient management.Maximizing accuracy of imaging in the context ofFLL is paramount in avoiding unnecessary biopsies,which may result in post-procedural complications. Atremendous development of new imaging techniqueshas taken place during these last years. Nowadays,Magnetic resonance imaging (MRI) plays a key rolein management of liver lesions, using a radiation-freetechnique and a safe contrast agent profile. MRI playsa key role in the non-invasive correct characterizationof FLL. MRI is capable of providing comprehensiveand highly accurate diagnostic information, withthe additional advantage of lack of harmful ionizingradiation. These properties make MRI the mainstay forthe noninvasive evaluation of focal liver lesions. In thispaper we review the state-of-the-art MRI liver protocol,briefly discussing different sequence types, the uniquecharacteristics of imaging non-cooperative patients anddiscuss the role of hepatocyte-specific contrast agents.A review of the imaging features of the most commonbenign and malignant FLL is presented, supplementedby a schematic representation of a simplistic practicalapproach on MRI.

  19. Magnetic Resonance Imaging of Pituitary Tumors.

    Science.gov (United States)

    Bonneville, Jean-François

    2016-01-01

    Magnetic Resonance Imaging (MRI) is currently considered a major keystone of the diagnosis of diseases of the hypothalamic-hypophyseal region. However, the relatively small size of the pituitary gland, its location deep at the skull base and the numerous physiological variants present in this area impede the precise assessment of the anatomical structures and, particularly, of the pituitary gland itself. The diagnosis of the often tiny lesions of this region--such as pituitary microadenomas--is then difficult if the MRI technology is not optimized and if potential artifacts and traps are not recognized. Advanced MRI technology can not only depict small lesions with greater reliability, but also help in the differential diagnosis of large tumors. In these, defining the presence or absence of invasion is a particularly important task. This review describes and illustrates the radiological diagnosis of the different tumors of the sellar region, from the common prolactinomas, nonfunctioning adenomas and Rathke's cleft cysts, to the less frequent and more difficult to detect corticotroph pituitary adenomas in Cushing's disease, and other neoplastic and nonneoplastic entities. Finally, some hints are given to facilitate the differential diagnosis of sellar lesions. PMID:27003878

  20. Statistical normalization techniques for magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Russell T. Shinohara

    2014-01-01

    Full Text Available While computed tomography and other imaging techniques are measured in absolute units with physical meaning, magnetic resonance images are expressed in arbitrary units that are difficult to interpret and differ between study visits and subjects. Much work in the image processing literature on intensity normalization has focused on histogram matching and other histogram mapping techniques, with little emphasis on normalizing images to have biologically interpretable units. Furthermore, there are no formalized principles or goals for the crucial comparability of image intensities within and across subjects. To address this, we propose a set of criteria necessary for the normalization of images. We further propose simple and robust biologically motivated normalization techniques for multisequence brain imaging that have the same interpretation across acquisitions and satisfy the proposed criteria. We compare the performance of different normalization methods in thousands of images of patients with Alzheimer's disease, hundreds of patients with multiple sclerosis, and hundreds of healthy subjects obtained in several different studies at dozens of imaging centers.

  1. Scatter-based magnetic resonance elastography

    International Nuclear Information System (INIS)

    Elasticity is a sensitive measure of the microstructural constitution of soft biological tissues and increasingly used in diagnostic imaging. Magnetic resonance elastography (MRE) uniquely allows in vivo measurement of the shear elasticity of brain tissue. However, the spatial resolution of MRE is inherently limited as the transformation of shear wave patterns into elasticity maps requires the solution of inverse problems. Therefore, an MRE method is introduced that avoids inversion and instead exploits shear wave scattering at elastic interfaces between anatomical regions of different shear compliance. This compliance-weighted imaging (CWI) method can be used to evaluate the mechanical consistency of cerebral lesions or to measure relative stiffness differences between anatomical subregions of the brain. It is demonstrated that CWI-MRE is sensitive enough to reveal significant elasticity variations within inner brain parenchyma: the caudate nucleus (head) was stiffer than the lentiform nucleus and the thalamus by factors of 1.3 ± 0.1 and 1.7 ± 0.2, respectively (P < 0.001). CWI-MRE provides a unique method for characterizing brain tissue by identifying local stiffness variations.

  2. Compression-sensitive magnetic resonance elastography

    Science.gov (United States)

    Hirsch, Sebastian; Beyer, Frauke; Guo, Jing; Papazoglou, Sebastian; Tzschaetzsch, Heiko; Braun, Juergen; Sack, Ingolf

    2013-08-01

    Magnetic resonance elastography (MRE) quantifies the shear modulus of biological tissue to detect disease. Complementary to the shear elastic properties of tissue, the compression modulus may be a clinically useful biomarker because it is sensitive to tissue pressure and poromechanical interactions. In this work, we analyze the capability of MRE to measure volumetric strain and the dynamic bulk modulus (P-wave modulus) at a harmonic drive frequency commonly used in shear-wave-based MRE. Gel phantoms with various densities were created by introducing CO2-filled cavities to establish a compressible effective medium. The dependence of the effective medium's bulk modulus on phantom density was investigated via static compression tests, which confirmed theoretical predictions. The P-wave modulus of three compressible phantoms was calculated from volumetric strain measured by 3D wave-field MRE at 50 Hz drive frequency. The results demonstrate the MRE-derived volumetric strain and P-wave modulus to be sensitive to the compression properties of effective media. Since the reconstruction of the P-wave modulus requires third-order derivatives, noise remains critical, and P-wave moduli are systematically underestimated. Focusing on relative changes in the effective bulk modulus of tissue, compression-sensitive MRE may be useful for the noninvasive detection of diseases involving pathological pressure alterations such as hepatic hypertension or hydrocephalus.

  3. Segmentation of neuroanatomy in magnetic resonance images

    Science.gov (United States)

    Simmons, Andrew; Arridge, Simon R.; Barker, G. J.; Tofts, Paul S.

    1992-06-01

    Segmentation in neurological magnetic resonance imaging (MRI) is necessary for feature extraction, volume measurement and for the three-dimensional display of neuroanatomy. Automated and semi-automated methods offer considerable advantages over manual methods because of their lack of subjectivity, their data reduction capabilities, and the time savings they give. We have used dual echo multi-slice spin-echo data sets which take advantage of the intrinsically multispectral nature of MRI. As a pre-processing step, a rf non-uniformity correction is applied and if the data is noisy the images are smoothed using a non-isotropic blurring method. Edge-based processing is used to identify the skin (the major outer contour) and the eyes. Edge-focusing has been used to significantly simplify edge images and thus allow simple postprocessing to pick out the brain contour in each slice of the data set. Edge- focusing is a technique which locates significant edges using a high degree of smoothing at a coarse level and tracks these edges to a fine level where the edges can be determined with high positional accuracy. Both 2-D and 3-D edge-detection methods have been compared. Once isolated, the brain is further processed to identify CSF, and, depending upon the MR pulse sequence used, the brain itself may be sub-divided into gray matter and white matter using semi-automatic contrast enhancement and clustering methods.

  4. Computed tomography and magnetic resonance colonography

    International Nuclear Information System (INIS)

    Colon cancer is the second leading cause of cancer death in the western world. Adenomatous colorectal polyps, which are found in 30-50% of Americans more than 50 years old, are recognized as important precursors of malignancy. Probably most of the invasive colon carcinomas arise from polyps. For this reason an early detection of these polyps and their complete removal is a recognized strategy for the prevention of colon cancer. So far no single method for an early diagnois of colon polyps or colon cancer offers high sensitivity and specificity along with low cost and good patient accccf Endo-opic colonoscopy allows the accurate detection of very small lesions and has since almost completely replaced fluooscopy. Cross-sectional imaging techniques, including magnetic resonance imaging (MRI) and computed tomography (CT), are increasingly being considered imaging modalities for the detection of colorectal polyps. CT and MR colonography are new techniques for imaging of the colon. In symptomatic patients, these new techniques show promising results for the detection of polyps equal to or larger than 1 cm in diameter. (author)

  5. Magnetic resonance imaging in brachial plexus injury.

    Science.gov (United States)

    Caranci, F; Briganti, F; La Porta, M; Antinolfi, G; Cesarano, E; Fonio, P; Brunese, L; Coppolino, F

    2013-08-01

    Brachial plexus injury represents the most severe nerve injury of the extremities. While obstetric brachial plexus injury has showed a reduction in the number of cases due to the improvements in obstetric care, brachial plexus injury in the adult is an increasingly common clinical problem. The therapeutic measures depend on the pathologic condition and the location of the injury: Preganglionic avulsions are usually not amenable to surgical repair; function of some denervated muscles can be restored with nerve transfers from intercostals or accessory nerves and contralateral C7 transfer. Postganglionic avulsions are repaired with excision of the damaged segment and nerve autograft between nerve ends or followed up conservatively. Magnetic resonance imaging is the modality of choice for depicting the anatomy and pathology of the brachial plexus: It demonstrates the location of the nerve damage (crucial for optimal treatment planning), depicts the nerve continuity (with or without neuroma formation), or may show a completely disrupted/avulsed nerve, thereby aiding in nerve-injury grading for preoperative planning. Computed tomography myelography has the advantage of a higher spatial resolution in demonstration of nerve roots compared with MR myelography; however, it is invasive and shows some difficulties in the depiction of some pseudomeningoceles with little or no communication with the dural sac. PMID:23949940

  6. Magnetic resonance imaging in retropharyngeal tendinitis

    Energy Technology Data Exchange (ETDEWEB)

    Ekbon, K.; Annell, K.; Traeff, J.; Torhall, J. (Soeder Hospital, Stockholm (Sweden))

    1994-08-01

    Seven consecutive patients with acute retropharyngeal tendinitis underwent plain X-ray and magnetic resonance imaging (MRI) of the cervical spine. All seven had marked soft tissue swelling anterior to C1 and C2 on plain X-ray, and soft tissue calcification at this level was present in five of them. On MRI, there was markedly increased signal intensity on T[sub 2]-weighted images in the acute phase and intermediate signal intensity on T[sub 1]-weighted images, anterior to the level of CI and C2, often extending as far down as C6. These changes correlated well with the soft tissue swelling seen on conventional X-ray of the cervical spine. The maximum mid-sagittal thickness of the soft issues was significantly greater in the tendinitis patients than in 12 control subjects free of symptoms from the pharynx or the cervical spine. Treatment with non-steroidal anti-inflammatory drugs rapidly alleviated symptoms, and at follow-up MRI showed regression or complete restitution of the changes. In conclusion, MRI can visualize the edematous changes in the longus colli muscle and adds useful diagnostic information in suspected cases of acute retropharyngeal tendinitis. 9 refs., 4 figs., 3 tabs.

  7. NUCLEAR MAGNETIC RESONANCE STUDIES OF URANOCENES

    Energy Technology Data Exchange (ETDEWEB)

    Luke, Wayne D.; Streitwieser, Jr., Andrew

    1979-12-01

    In the past several years a substantial amount of work has been devoted toward evaluation of the contact and pseudocontact contributions to the observed isotropic shifts in H nuclear magnetic resonance (NMR) spectra of uranium(IV) organometallic compounds. One reason for interest in this area arises from using the presence of contact shifts as a prcbe for covalent character in the uranium carbon bonds in these compounds. Several extensive {sup 1}H NNR studies on Cp{sub 3} U-X compounds and less extensive studies on uranocenes have been reported. Interpretation of these results suggests that contact shifts-contribute significantly to the observed isotropic shifts. Their presence has been taken as indicative of covalent character of metal carbon bonds in these systems, but agreement is not complete. In this paper we shall review critically the work reported on uranocenes in the light of recent results and report recent work on attempted separation of the observed isotropic shifts in alkyluranocenes into contact and pseudocontact components.

  8. Potts disease: Diagnosis with magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Pursey, Jacqueline [MRI Department, Gartnavel General Hospitial, 1053 Great Western road, Glasgow G12 0YN (United Kingdom)], E-mail: Jacqueline.pursey@ggc.scot.nhs.uk; Stewart, Sharon [School of Health and Social Care, Caledonian University, Glasgow (United Kingdom)

    2010-02-15

    The eponymously named Potts disease is a relatively rare form of Tuberculosis (TB) which affects the spine. TB of the spine is one of the earliest diseases known to man and in the 20th century was thought to be a disease which had been defeated by the advent of antitubercular drugs. Over the last two decades there have been several reports which indicate a revival of TB in both the developing and developed world. Factors which may be contributing to this are the spread of the HIV virus, increased immigration and the emergence of drug resistant strains of the TB bacteria. Potts disease has an insidious onset and often the radiographic findings are far advanced when a diagnosis is finally reached. MRI is able to detect changes to the vertebrae in Potts disease earlier than radiographs. This case report outlines the clinical presentation of a young male with Potts disease who was HIV negative, and the important role that MRI plays in diagnosis and therefore in appropriate and timely intervention. The typical magnetic resonance (MR) imaging features and the radiographic hallmarks of the disease will also be discussed.

  9. Magnetic Resonance Elastography: Inversions in Bounded Media

    Science.gov (United States)

    Kolipaka, Arunark; McGee, Kiaran P.; Manduca, Armando; Romano, Anthony J.; Glaser, Kevin J.; Araoz, Philip A.; Ehman, Richard L.

    2009-01-01

    Magnetic resonance elastography (MRE) is a noninvasive imaging technique capable of quantifying and spatially resolving the shear stiffness of soft tissues by visualization of synchronized mechanical wave displacement fields. However, MRE inversions generally assume that the measured tissue motion consists primarily of shear waves propagating in a uniform, infinite medium. This assumption is not valid in organs such as the heart, eye, bladder, skin, fascia, bone and spinal cord in which the shear wavelength approaches the geometric dimensions of the object. The aim of this study was to develop and test mathematical inversion algorithms capable of resolving shear stiffness from displacement maps of flexural waves propagating in bounded media such as beams, plates and spherical shells using geometry-specific equations of motion. MRE and finite element modeling (FEM) of beam, plate, and spherical shell phantoms of various geometries were performed. Mechanical testing of the phantoms agreed with the stiffness values obtained from FEM and MRE data and a linear correlation of r2 ≥ 0.99 was observed between the stiffness values obtained using MRE and FEM data. In conclusion, we have demonstrated new inversion methods for calculating shear stiffness that may be more appropriate for waves propagating in bounded media. PMID:19780146

  10. Very low field magnetic resonance imaging

    International Nuclear Information System (INIS)

    The aim of this thesis is to perform Magnetic Resonance Imaging at very low field (from 1 mT to 10 mT). A new kind of sensor called 'mixed sensor' has been used to achieve a good detectivity at low frequencies. Combining a superconducting loop and a giant magnetoresistance, those detectors have a competitive equivalent field noise compared to existing devices (Tuned coils, SQUIDs and Atomic Magnetometers). They have been combined with flux transformers to increase the coupling between the sample and the sensor. A complete study has been performed to adapt it to mixed sensors and then maximize the gain. This set has been incorporated in an existing small MRI device to test its robustness in real conditions. In parallel, several MRI sequences (GE, SE, FLASH, EPI,...) have been integrated and adapted to very low field requirements. They have been used to perform in-vivo three dimensional imaging and relaxometry studies on well known products to test their reliability. Finally, a larger setup adapted for full-head imaging has been designed and built to perform images on a larger working volume. (author)

  11. Magnetic resonance tomography in confirmed multiple sclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Uhlenbrock, D.; Dickmann, E.; Beyer, H.K.; Gehlen, W.

    1985-03-01

    The authors report on 21 cases of confirmed multiple sclerosis examined by both CT and magnetic resonance tomography. To safeguard the results, strict criteria were applied in accordance with the suggestions made by neurological work teams. Pathological lesions were seen in 20 patients; the MR image did not reveal anything abnormal in one case. On the average, 10.3 lesions were seen in the MR tomogram, whereas CT images showed on the average only 2.1 foci. The size and number of lesions in the MR tomogram were independent of the duration of the disease, the presented clinical symptoms, or the type of treatment at the time of examination. Evidently the sensitivity of MR tomography is very high in MS patients, but it has not yet been clarified to what extent this applies also to the specificity. Further research is mandatory. First experiences made by us show that lesions of a similar kind can also occur in diseases such as malignant lymphoma involving the brain, in vitamin B 12 deficiency syndrome, or encephalitis, and can become manifest in the MR tomogram.

  12. Bolus characteristics based on Magnetic Resonance Angiography

    Directory of Open Access Journals (Sweden)

    Bi Xiaoming

    2006-10-01

    Full Text Available Abstract Background A detailed contrast bolus propagation model is essential for optimizing bolus-chasing Computed Tomography Angiography (CTA. Bolus characteristics were studied using bolus-timing datasets from Magnetic Resonance Angiography (MRA for adaptive controller design and validation. Methods MRA bolus-timing datasets of the aorta in thirty patients were analyzed by a program developed with MATLAB. Bolus characteristics, such as peak position, dispersion and bolus velocity, were studied. The bolus profile was fit to a convolution function, which would serve as a mathematical model of bolus propagation in future controller design. Results The maximum speed of the bolus in the aorta ranged from 5–13 cm/s and the dwell time ranged from 7–13 seconds. Bolus characteristics were well described by the proposed propagation model, which included the exact functional relationships between the parameters and aortic location. Conclusion The convolution function describes bolus dynamics reasonably well and could be used to implement the adaptive controller design.

  13. Musculoskeletal magnetic resonance imaging: importance of radiography

    Energy Technology Data Exchange (ETDEWEB)

    Taljanovic, Mihra S.; Hunter, Tim B.; Fitzpatrick, Kimberly A. [Department of Radiology, The University of Arizona Health Sciences Center, 1501 N. Campbell Avenue, AZ 85724, Tucson (United States); Krupinski, Elizabeth A. [Department of Radiology, University of Arizona, 1609 N. Warren, Building 211, AZ 85724, Tucson (United States); Pope, Thomas L. [Department of Radiology, Medical University of South Carolina, 169 Ashley Avenue, P.O. Box 250322, SC 29425, Charleston (United States)

    2003-07-01

    To determine the usefulness of radiography for interpretation of musculoskeletal (MSK) magnetic resonance imaging (MRI) studies. In a 1-year period, 1,030 MSK MRI studies were performed in 1,002 patients in our institution. For each study, the interpreting radiologist completed a questionnaire regarding the availability and utility of radiographs, radiological reports and clinical information for the interpretation of the MRI study. Radiographs were essential, very important or added information in 61-75% of all MSK MRI cases. Radiographs were judged as essential for reading of MRI studies more often for trauma, infection/inflammation and tumors than for degenerative and miscellaneous/normal diagnoses ({chi}{sup 2}=60.95, df=16, P<0.0001). The clinical information was rated as ''essential'' or ''useful'' significantly more often than not ({chi}{sup 2}=93.07, df=16, P<0.0001). The clinical and MRI diagnoses were the same or partially concordant significantly more often for tumors than for trauma, infection/inflammation and degenerative conditions, while in the miscellaneous/normal group they were different in 64% of cases. When the diagnoses were different, there were more instances in which radiographs were not available. Radiographs are an important, and sometimes essential, initial complementary study for reading of MSK MRI examinations. It is highly recommended that radiographs are available when MSK MRI studies are interpreted. (orig.)

  14. Planar Atom Trap and Magnetic Resonance 'Lens' Designs

    CERN Document Server

    Barbic, M; Emery, T H; Scherer, A

    2007-01-01

    We present various planar magnetic designs that create points above the plane where the magnitude of the static magnetic field is a local minimum. Structures with these properties are of interest in the disciplines of neutral atom confinement, magnetic levitation, and magnetic resonance imaging. Each planar permanent magnet design is accompanied by the equivalent planar single non-crossing conductor design. Presented designs fall into three categories producing: a) zero value magnetic field magnitude point minima, b) non-zero magnetic field magnitude point minima requiring external bias magnetic field, and c) self-biased non-zero magnetic field magnitude point minima. We also introduce the Principle of Amperean Current Doubling in planar perpendicularly magnetized thin films that can be used to improve the performance of each permanent magnet design we present. Single conductor current-carrying designs are suitable for single layer lithographic fabrication, as we experimentally demonstrate. Finally, we presen...

  15. Dynamic nuclear polarization in a magnetic resonance force microscope experiment.

    Science.gov (United States)

    Issac, Corinne E; Gleave, Christine M; Nasr, Paméla T; Nguyen, Hoang L; Curley, Elizabeth A; Yoder, Jonilyn L; Moore, Eric W; Chen, Lei; Marohn, John A

    2016-04-01

    We report achieving enhanced nuclear magnetization in a magnetic resonance force microscope experiment at 0.6 tesla and 4.2 kelvin using the dynamic nuclear polarization (DNP) effect. In our experiments a microwire coplanar waveguide delivered radiowaves to excite nuclear spins and microwaves to excite electron spins in a 250 nm thick nitroxide-doped polystyrene sample. Both electron and proton spin resonance were observed as a change in the mechanical resonance frequency of a nearby cantilever having a micron-scale nickel tip. NMR signal, not observable from Curie-law magnetization at 0.6 T, became observable when microwave irradiation was applied to saturate the electron spins. The resulting NMR signal's size, buildup time, dependence on microwave power, and dependence on irradiation frequency was consistent with a transfer of magnetization from electron spins to nuclear spins. Due to the presence of an inhomogeneous magnetic field introduced by the cantilever's magnetic tip, the electron spins in the sample were saturated in a microwave-resonant slice 10's of nm thick. The spatial distribution of the nuclear polarization enhancement factor ε was mapped by varying the frequency of the applied radiowaves. The observed enhancement factor was zero for spins in the center of the resonant slice, was ε = +10 to +20 for spins proximal to the magnet, and was ε = -10 to -20 for spins distal to the magnet. We show that this bipolar nuclear magnetization profile is consistent with cross-effect DNP in a ∼10(5) T m(-1) magnetic field gradient. Potential challenges associated with generating and using DNP-enhanced nuclear magnetization in a nanometer-resolution magnetic resonance imaging experiment are elucidated and discussed. PMID:26964007

  16. Dynamic nuclear polarization in a magnetic resonance force microscope experiment.

    Science.gov (United States)

    Issac, Corinne E; Gleave, Christine M; Nasr, Paméla T; Nguyen, Hoang L; Curley, Elizabeth A; Yoder, Jonilyn L; Moore, Eric W; Chen, Lei; Marohn, John A

    2016-04-01

    We report achieving enhanced nuclear magnetization in a magnetic resonance force microscope experiment at 0.6 tesla and 4.2 kelvin using the dynamic nuclear polarization (DNP) effect. In our experiments a microwire coplanar waveguide delivered radiowaves to excite nuclear spins and microwaves to excite electron spins in a 250 nm thick nitroxide-doped polystyrene sample. Both electron and proton spin resonance were observed as a change in the mechanical resonance frequency of a nearby cantilever having a micron-scale nickel tip. NMR signal, not observable from Curie-law magnetization at 0.6 T, became observable when microwave irradiation was applied to saturate the electron spins. The resulting NMR signal's size, buildup time, dependence on microwave power, and dependence on irradiation frequency was consistent with a transfer of magnetization from electron spins to nuclear spins. Due to the presence of an inhomogeneous magnetic field introduced by the cantilever's magnetic tip, the electron spins in the sample were saturated in a microwave-resonant slice 10's of nm thick. The spatial distribution of the nuclear polarization enhancement factor ε was mapped by varying the frequency of the applied radiowaves. The observed enhancement factor was zero for spins in the center of the resonant slice, was ε = +10 to +20 for spins proximal to the magnet, and was ε = -10 to -20 for spins distal to the magnet. We show that this bipolar nuclear magnetization profile is consistent with cross-effect DNP in a ∼10(5) T m(-1) magnetic field gradient. Potential challenges associated with generating and using DNP-enhanced nuclear magnetization in a nanometer-resolution magnetic resonance imaging experiment are elucidated and discussed.

  17. Preoperative functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS)

    DEFF Research Database (Denmark)

    Hartwigsen, G.; Siebner, Hartwig R.; Stippich, C.

    2010-01-01

    of essential cortex, it cannot provide information preoperatively for surgical planning.Brain imaging techniques such as functional magnetic resonance imaging (fMRI), magnetoencephalography (MEG) and transcranial magnetic stimulation (TMS) are increasingly being used to localize functionally critical cortical...

  18. Beam induced electron cloud resonances in dipole magnetic fields

    Science.gov (United States)

    Calvey, J. R.; Hartung, W.; Makita, J.; Venturini, M.

    2016-07-01

    The buildup of low energy electrons in an accelerator, known as electron cloud, can be severely detrimental to machine performance. Under certain beam conditions, the beam can become resonant with the cloud dynamics, accelerating the buildup of electrons. This paper will examine two such effects: multipacting resonances, in which the cloud development time is resonant with the bunch spacing, and cyclotron resonances, in which the cyclotron period of electrons in a magnetic field is a multiple of bunch spacing. Both resonances have been studied directly in dipole fields using retarding field analyzers installed in the Cornell Electron Storage Ring. These measurements are supported by both analytical models and computer simulations.

  19. Resonant Raman Scattering from Silicon Nanoparticles Enhanced by Magnetic Response

    CERN Document Server

    Dmitriev, Pavel A; Milichko, Valentin A; Makarov, Sergey V; Mukhin, Ivan S; Samusev, Anton K; Krasnok, Alexander E; Belov, Pavel A; Kivshar, Yuri S

    2016-01-01

    Enhancement of optical response with high-index dielectric nanoparticles is attributed to the excitation of their Mie-type magnetic and electric resonances. Here we study Raman scattering from crystalline silicon nanoparticles and reveal that magnetic dipole modes have much stronger effect on the scattering than electric modes of the same order. We demonstrate experimentally a 140-fold enhancement of Raman signal from individual silicon spherical nanoparticles at the magnetic dipole resonance. Our results confirm the importance of the optically-induced magnetic response of subwavelength dielectric nanoparticles for enhancing light-matter interactions.

  20. Resonant Raman scattering from silicon nanoparticles enhanced by magnetic response.

    Science.gov (United States)

    Dmitriev, Pavel A; Baranov, Denis G; Milichko, Valentin A; Makarov, Sergey V; Mukhin, Ivan S; Samusev, Anton K; Krasnok, Alexander E; Belov, Pavel A; Kivshar, Yuri S

    2016-05-01

    Enhancement of optical response with high-index dielectric nanoparticles is attributed to the excitation of their Mie-type magnetic and electric resonances. Here we study Raman scattering from crystalline silicon nanoparticles and reveal that magnetic dipole modes have a much stronger effect on the scattering than electric modes of the same order. We demonstrate experimentally a 140-fold enhancement of the Raman signal from individual silicon spherical nanoparticles at the magnetic dipole resonance. Our results confirm the importance of the optically-induced magnetic response of subwavelength dielectric nanoparticles for enhancing light-matter interactions. PMID:27113352

  1. Nuclear magnetic resonance data of C9H11ITe

    Science.gov (United States)

    Mikhova, B. M.

    This document is part of Part 6 `Organic Metalloid Compounds' of Subvolume D 'Chemical Shifts and Coupling Constants for Carbon-13' of Landolt-Börnstein III/35 'Nuclear Magnetic Resonance Data', Group III 'Condensed Matter'.

  2. Nuclear magnetic resonance data of C10H13ITe

    Science.gov (United States)

    Mikhova, B. M.

    This document is part of Part 6 `Organic Metalloid Compounds' of Subvolume D 'Chemical Shifts and Coupling Constants for Carbon-13' of Landolt-Börnstein III/35 'Nuclear Magnetic Resonance Data', Group III 'Condensed Matter'.

  3. Normal perinatal and paediatric postmortem magnetic resonance imaging appearances

    Energy Technology Data Exchange (ETDEWEB)

    Arthurs, Owen J. [Department of Radiology, Great Ormond Street Hospital for Children NHS Foundation Trust, London (United Kingdom); UCL Institute of Child Health, London (United Kingdom); Barber, Joy L. [Department of Radiology, Great Ormond Street Hospital for Children NHS Foundation Trust, London (United Kingdom); Taylor, Andrew M. [Cardiorespiratory Division, Great Ormond Street Hospital for Children NHS Foundation Trust, London (United Kingdom); UCL Institute of Cardiovascular Science, Centre for Cardiovascular Imaging, London (United Kingdom); Sebire, Neil J. [UCL Institute of Child Health, London (United Kingdom); Department of Histopathology, Great Ormond Street Hospital for Children NHS Foundation Trust, London (United Kingdom)

    2015-04-01

    As postmortem imaging becomes more widely used following perinatal and paediatric deaths, the correct interpretation of images becomes imperative, particularly given the increased use of postmortem magnetic resonance imaging. Many pathological processes may have similar appearances in life and following death. A thorough knowledge of normal postmortem changes is therefore required within postmortem magnetic resonance imaging to ensure that these are not mistakenly interpreted as significant pathology. Similarly, some changes that are interpreted as pathological if they occur during life may be artefacts on postmortem magnetic resonance imaging that are of limited significance. This review serves to illustrate briefly those postmortem magnetic resonance imaging changes as part of the normal changes after death in fetuses and children, and highlight imaging findings that may confuse or mislead an observer to identifying pathology where none is present. (orig.)

  4. Categorization of aortic aneurysm thrombus morphology by magnetic resonance imaging

    DEFF Research Database (Denmark)

    de la Motte, Louise; Pedersen, Mads Møller; Thomsen, Carsten;

    2013-01-01

    Magnetic resonance imaging (MRI) has been proposed for qualitative categorization of intraluminal thrombus morphology. We aimed to correlate the qualitative MRI categorization previously described to quantitative measurements of signal intensity and to compare morphological characteristics of int...

  5. Diffusion-weighted magnetic resonance imaging in ileocolonic Crohn's disease

    DEFF Research Database (Denmark)

    Juel, Mie A; Rafaelsen, Søren Rafael; Nathan, Torben;

    Background: Diffusion-weighted magnetic resonance imaging (dw- MRI) utilizes differences in the motion of water molecules between tissues for image formation without administration of contrast materials. Inflammation in the bowel wall slows water transit resulting in lower apparent diffusions...

  6. Soft Tissue Edema Around Musculoskeletal Sarcomas at Magnetic Resonance Imaging

    OpenAIRE

    Panicek, David M.; Schwartz, Lawrence H.

    1997-01-01

    The presence of soft tissue edema around a malignant musculoskeletal neoplasm can interfere with accurate local tumor staging at magnetic resonance imaging. This article discusses and illustrates such edema, emphasizing means for avoiding misinterpretation of edema and subsequent overstaging.

  7. Magnetic resonance tomography for trauma of the cervical spine

    International Nuclear Information System (INIS)

    Twenty patients who had suffered spinal trauma were examined by magnetic resonance tomography. Fifteen patients with first degree trauma in Erdmann's classification showed no abnormality. Magnetic resonance tomography of the cervical spine appears to be a suitable method for investigating patients with whiplash injuries. It is indicated following severe flexion injuries with subluxations and neurological symptoms, since it is the only method that can demonstrate the spinal cord directly and completely and show the extent of cord compression. For patients with thoracic trauma and rapidly developing neurological symptoms, magnetic resonance tomography is ideal for showing post-traumatic syringomyelia. Magnetic resonance tomography following whiplash injuries is recommended if plain films of the cervical spine show any abnormalities, as well as for the investigation of acute or sub-acute neurological abnormalities. The various findings are discussed. (orig.)

  8. [Magnetic resonance tomography in injuries of the cervical spine].

    Science.gov (United States)

    Meydam, K; Sehlen, S; Schlenkhoff, D; Kiricuta, J C; Beyer, H K

    1986-12-01

    Twenty patients who had suffered spinal trauma were examined by magnetic resonance tomography. Fifteen patients with first degree trauma in Erdmann's classification showed no abnormality. Magnetic resonance tomography of the cervical spine appears to be a suitable method for investigating patients with whiplash injuries. It is indicated following severe flexion injuries with subluxations and neurological symptoms, since it is the only method that can demonstrate the spinal cord directly and completely and show the extent of cord compression. For patients with thoracic trauma and rapidly developing neurological symptoms, magnetic resonance tomography is ideal for showing post-traumatic syringomyelia. Magnetic resonance tomography following whiplash injuries is recommended if plain films of the cervical spine show any abnormalities, as well as for the investigation of acute or sub-acute neurological abnormalities. The various findings are discussed. PMID:3025951

  9. Magnetic resonance tomography for trauma of the cervical spine

    Energy Technology Data Exchange (ETDEWEB)

    Meydam, K.; Sehlen, S.; Schlenkhoff, D.; Kiricuta, J.C.; Beyer, H.K.

    1986-12-01

    Twenty patients who had suffered spinal trauma were examined by magnetic resonance tomography. Fifteen patients with first degree trauma in Erdmann's classification showed no abnormality. Magnetic resonance tomography of the cervical spine appears to be a suitable method for investigating patients with whiplash injuries. It is indicated following severe flexion injuries with subluxations and neurological symptoms, since it is the only method that can demonstrate the spinal cord directly and completely and show the extent of cord compression. For patients with thoracic trauma and rapidly developing neurological symptoms, magnetic resonance tomography is ideal for showing post-traumatic syringomyelia. Magnetic resonance tomography following whiplash injuries is recommended if plain films of the cervical spine show any abnormalities, as well as for the investigation of acute or sub-acute neurological abnormalities. The various findings are discussed.

  10. Magnetic resonance imaging appearance of hypertensive encephalopathy in a dog

    OpenAIRE

    Bowman, Chloe A; Witham, Adrian; Tyrrell, Dayle; Long, Sam N

    2015-01-01

    A 16-year-old female spayed English Staffordshire terrier was presented for evaluation of a 10-month history of intermittent myoclonic episodes, and a one weeks history of short episodes of altered mentation, ataxia and collapse. Magnetic resonance imaging identified subcortical oedema, predominately in the parietal and temporal lobes and multiple cerebral microbleeds. Serum biochemistry, indirect blood pressure measurements and magnetic resonance imaging abnormalities were consistent with hy...

  11. Magnetic resonance imaging in entomology: a critical review

    OpenAIRE

    Hart, A.G.; Bowtell, R W; Köckenberger, W; Wenseleers, T.; Ratnieks, F.L.W.

    2005-01-01

    Magnetic resonance imaging (MRI) enables in vivo imaging of organisms. The recent development of the magnetic resonance microscope (MRM) has enabled organisms within the size range of many insects to be imaged. Here, we introduce the principles of MRI and MRM and review their use in entomology. We show that MRM has been successfully applied in studies of parasitology, development, metabolism, biomagnetism and morphology, and the advantages and disadvantages relative to other imaging technique...

  12. Cardiovascular magnetic resonance physics for clinicians: part I

    OpenAIRE

    Ridgway John P

    2010-01-01

    Abstract There are many excellent specialised texts and articles that describe the physical principles of cardiovascular magnetic resonance (CMR) techniques. There are also many texts written with the clinician in mind that provide an understandable, more general introduction to the basic physical principles of magnetic resonance (MR) techniques and applications. There are however very few texts or articles that attempt to provide a basic MR physics introduction that is tailored for clinician...

  13. Magnetic resonance studies of brain function and neurochemistry

    OpenAIRE

    Uǧurbil, K.; Adriany, G.; Andersen, P; Chen, W.; Gruetter, R.; Hu, X.; Merkle, H; Kim, D.-S.; Kim, S. -G.; Strupp, J.; Zhu, X H; Ogawa, S

    2000-01-01

    In the short time since its introduction, magnetic resonance imaging (MRI) has rapidly evolved to become an indispensable tool for clinical diagnosis and biomedical research. Recently, this methodology has been successfully used for the acquisition of functional, physiological, and biochemical information in intact systems, particularly in the human body. The ability to map areas of altered neuronal activity in the brain, often referred to as functional magnetic resonance imaging (fMRI), is p...

  14. Lymphoma of uterine cervix: magnetic resonance imaging findings

    Energy Technology Data Exchange (ETDEWEB)

    Kanaan, Daniel; Constantino, Carolina Pesce Lamas; Souza, Rodrigo Canellas de, E-mail: daniel.kanaan@hotmail.com [Department of Radiology, Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Parente, Daniella Braz [Instituto D' Or de Pesquisa e Ensino, Rio de Janeiro, RJ (Brazil)

    2012-05-15

    Lymphoma of the cervix is a rare disease. About 1.0% to 1.5% of extranodal lymphomas originates in the female genital tract. The clinical presentation of this condition is nonspecific and magnetic resonance imaging is important for diagnostic elucidation. The present report describes the case of a 80-year-old patient with lumbar pain, whose magnetic resonance imaging showed a large uterine mass. The final diagnosis was lymphoma. (author)

  15. Magnetic resonance spectroscopy and imaging in cerebral ischemia

    International Nuclear Information System (INIS)

    In-vivo proton and phosphorus magnetic resonance spectroscopy was used to detect changes in cerebral metabolism during ischemia and other types of metabolic stress. Magnetic resonance imaging was performed in an animal model to observe morphological alterations during focal cerebral ischemia. Spectroscopy was performed in animal models with global ischemia, in volunteers during hyperventilation and pharmaco-logically altered cerebral perfusion, and in patients with acute and prolonged focal cerebral ischemia. (author). 396 refs.; 44 figs.; 14 tabs

  16. Implementation of Quantum Logic Gates by Nuclear Magnetic Resonance Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    DU Jiang-Feng; WU Ji-Hui; SHI Ming-Jun; HAN Liang; ZHOU Xian-Yi; YE Bang-Jiao; WENG Hui-Ming; HAN Rong-Dian

    2000-01-01

    Using nuclear magnetic resonance techniques with a solution of cytosine molecules, we show an implementation of certain quantum logic gates (including NOT gate, square-root of NOT gate and controlled-NOT gate), which have central importance in quantum computing. In addition, experimental results show that nuclear magnetic resonance spectroscopy can efficiently measure the result of quantum computing without attendant wave-function collapse.

  17. Patient perception of magnetic resonance arthrography

    Energy Technology Data Exchange (ETDEWEB)

    Robbins, M.I.; Anzilotti, K.F. Jr.; Katz, L.D.; Lange, R.C. [Dept. of Diagnostic Radiology, Yale University School of Medicine, New Haven, CT (United States)

    2000-05-01

    Objective. Magnetic resonance (MR) arthrography has been demonstrated to be more accurate than MR imaging alone in the identification of a variety of musculoskeletal pathology. While the complication rate of intra-articular gadolinium: saline injection has been shown to be relatively low, MR arthrography is more invasive, painful, and costly, and less convenient, than MR imaging alone. The purpose of this study was to evaluate patients' perception of the fear and discomfort, and to assess their overall acceptance of the intra-articular gadolinium injection.Design and patients. Between October 1997 and January 1998, 113 outpatients who were referred to Yale-New Haven Hospital for MR arthrography of the ankle, elbow, hip, knee, shoulder, or wrist were asked to complete a questionnaire rating their fear of factors most commonly associated with the procedure including ''pain'', ''needles'', ''complications'', and ''discovery of results that would lead to surgery''. In addition, after having undergone the intra-articular gadolinium:saline injection, patients were asked to rate their perception of pain.Results. While many patients expressed fear of ''pain'' and ''needles'', after having undergone the injection their overall pain rating score was low. Only 6% actually found gadolinium arthrography more painful than expected.Conclusion. Despite the fact that patients expressed apprehension about certain aspects of MR arthrography, subjects who underwent the intra-articular gadolinium injection considered the discomfort less than expected. Clinicians should not hesitate to order MR arthrography because the accuracy of the procedure is high enough that patients accept the discomfort. (orig.)

  18. Recent advances in cardiac magnetic resonance.

    Science.gov (United States)

    Greulich, Simon; Arai, Andrew E; Sechtem, Udo; Mahrholdt, Heiko

    2016-01-01

    Cardiac magnetic resonance (CMR) is a non-invasive imaging modality that has rapidly emerged during the last few years and has become a valuable, well-established clinical tool. Beside the evaluation of anatomy and function, CMR has its strengths in providing detailed non-invasive myocardial tissue characterization, for which it is considered the current diagnostic gold standard. Late gadolinium enhancement (LGE), with its capability to detect necrosis and to separate ischemic from non-ischemic cardiomyopathies by distinct LGE patterns, offers unique clinical possibilities. The presence of LGE has also proven to be a good predictor of an adverse outcome in various studies. T2-weighted (T2w) images, which are supposed to identify areas of edema and inflammation, are another CMR approach to tissue characterization. However, T2w images have not held their promise owing to several technical limitations and potential physiological concerns. Newer mapping techniques may overcome some of these limitations: they assess quantitatively myocardial tissue properties in absolute terms and show promising results in studies for characterization of diffuse fibrosis (T1 mapping) and/or inflammatory processes (T2 mapping). However, these techniques are still research tools and are not part of the clinical routine yet. T2* CMR has had significant impact in the management of thalassemia because it is possible to image the amount of iron in the heart and the liver, improving both diagnostic imaging and the management of patients with thalassemia. CMR findings frequently have clinical impact on further patient management, and CMR seems to be cost effective in the clinical routine. PMID:27635240

  19. Magnetic resonance imaging of spinal dysraphism

    Energy Technology Data Exchange (ETDEWEB)

    Akino, Minoru; Isu, Toyohiko; Iwasaki, Yoshinobu; Abe, Hiroshi; Abe, Satoru; Miyasaka, Kazuo; Nomura, Mikio; Saito, Hisatoshi.

    1988-04-01

    Nineteen patients with lumbosacral spina bifida were studied by magnetic resonance imaging (MRI) and were divided into two groups: those with lumbosacral lipoma and those with meningomyelocele. All of the patients with meningomyelocele underwent surgery soon after birth for closure of the skin defect. Whenever possible, examination was not confined to the lumbosacral area but also included the brain and other portions of the spinal cord. Certain similarities and differences in pathology were ascertained in the two groups. The tethered cords were the same in both groups. However, Chiari malformations were observed only in patients with meningomyelocele, and hydrocephalus occurred only in patients with Chiari malformations. Syringomyelia and scoliosis were detected in both groups, but scoliosis was more prevalent in the meningomyelocele group. There appeared to be a correlation between scoliosis and syringomyelia; in five of the seven cases of syringomyelia, the locations of the scoliosis and syringomyelia were the same. With MRI, these complex pathologies, including tethered cord, syringomyelia, scoliosis, Chiari malformations, and hydrocephalus, were easily visualized. The superiority of MRI over conventional X-ray technology has been well established. First, a direct image of the spinal cord is obtained. Second, there is no necessity for injection of contrast material into the intrathecal space. Third, any scanning field is possible. There are also some disadvantages with MRI. First, the spatial resolution is inferior to that of high-resolution computed tomography. Second, MRI cannot provide information concerning bone cortex. Therefore, bone involvement cannot be accurately diagnosed. However, in the assessment of spinal dysraphism, MRI is an excellent diagnostic tool and should be the preferred method of diagnosing spinal dysraphism.

  20. Magnetic Resonance Features of Cerebral Malaria

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, P.; Sharma, R.; Kumar, S.; Kumar, U. (Dept. of Radiodiagnosis and Dept. of Medicine, All India Institute of Medical Sciences, New Delhi (India))

    2008-06-15

    Background: Cerebral malaria is a major health hazard, with a high incidence of mortality. The disease is endemic in many developing countries, but with a greater increase in tourism, occasional cases may be detected in countries where the disease in not prevalent. Early diagnosis and evaluation of cerebral involvement in malaria utilizing modern imaging modalities have an impact on the treatment and clinical outcome. Purpose: To evaluate the magnetic resonance (MR) features of patients with cerebral malaria presenting with altered sensorium. Material and Methods: We present the findings in three patients with cerebral malaria presenting with altered sensorium. MR imaging using a 1.5-Tesla unit was carried out. The sequences performed were 5-mm-thick T1-weighted, T2-weighted, fluid-attenuated inversion-recovery (FLAIR), and T2-weighted gradient-echo axial sequences, and sagittal and coronal FLAIR. Diffusion-weighted imaging was performed with b values of 0 and 1000 s/mm2, and apparent diffusion coefficient (ADC) maps were obtained. Results: Focal hyperintensities in the bilateral periventricular white matter, corpus callosum, occipital subcortex, and bilateral thalami were noticed on T2-weighted and FLAIR sequences. The lesions were more marked in the splenium of the corpus callosum. No enhancement on postcontrast T1-weighted MR images was observed. There was no evidence of restricted diffusion on the diffusion-weighted sequence and ADC map. Conclusion: MR is a sensitive imaging modality, with a role in the assessment of cerebral lesions in malaria. Focal white matter and corpus callosal lesions without any restricted diffusion were the key findings in our patients

  1. Magnetic resonance imaging of spinal dysraphism

    International Nuclear Information System (INIS)

    Nineteen patients with lumbosacral spina bifida were studied by magnetic resonance imaging (MRI) and were divided into two groups: those with lumbosacral lipoma and those with meningomyelocele. All of the patients with meningomyelocele underwent surgery soon after birth for closure of the skin defect. Whenever possible, examination was not confined to the lumbosacral area but also included the brain and other portions of the spinal cord. Certain similarities and differences in pathology were ascertained in the two groups. The tethered cords were the same in both groups. However, Chiari malformations were observed only in patients with meningomyelocele, and hydrocephalus occurred only in patients with Chiari malformations. Syringomyelia and scoliosis were detected in both groups, but scoliosis was more prevalent in the meningomyelocele group. There appeared to be a correlation between scoliosis and syringomyelia; in five of the seven cases of syringomyelia, the locations of the scoliosis and syringomyelia were the same. With MRI, these complex pathologies, including tethered cord, syringomyelia, scoliosis, Chiari malformations, and hydrocephalus, were easily visualized. The superiority of MRI over conventional X-ray technology has been well established. First, a direct image of the spinal cord is obtained. Second, there is no necessity for injection of contrast material into the intrathecal space. Third, any scanning field is possible. There are also some disadvantages with MRI. First, the spatial resolution is inferior to that of high-resolution computed tomography. Second, MRI cannot provide information concerning bone cortex. Therefore, bone involvement cannot be accurately diagnosed. However, in the assessment of spinal dysraphism, MRI is an excellent diagnostic tool and should be the preferred method of diagnosing spinal dysraphism. (author)

  2. Magnetic Resonance Imaging in Postprostatectomy Radiotherapy Planning

    International Nuclear Information System (INIS)

    Purpose: To investigate whether the use of magnetic resonance imaging (MRI) in prostate bed treatment planning could influence definition of the clinical target volume (CTV) and organs at risk. Methods and Materials: A total of 21 consecutive patients referred for prostate bed radiotherapy were included in the present retrospective study. The CTV was delineated according to the European Organization for Research and Treatment of Cancer recommendations on computed tomography (CT) and T1-weighted (T1w) and T2-weighted (T2w) MRI. The CTV magnitude, agreement, and spatial differences were evaluated on the planning CT scan after registration with the MRI scans. Results: The CTV was significantly reduced on the T1w and T2w MRI scans (13% and 9%, respectively) compared with the CT scans. The urinary bladder was drawn smaller on the CT scans and the rectum was smaller on the MRI scans. On T1w MRI, the rectum and urinary bladder were delineated larger than on T2w MRI. Minimal agreement was observed between the CT and T2w images. The main spatial differences were measured in the superior and superolateral directions in which the CTV on the MRI scans was 1.8–2.9 mm smaller. In the posterior and inferior border, no difference was seen between the CT and T1w MRI scans. On the T2w MRI scans, the CTV was larger in these directions (by 1.3 and 1.7 mm, respectively). Conclusions: The use of MRI in postprostatectomy radiotherapy planning resulted in a reduction of the CTV. The main differences were found in the superior part of the prostate bed. We believe T2w MRI enables more precise definition of prostate bed CTV than conventional planning CT.

  3. Can magnetic resonance spectroscopy differentiate endometrial cancer?

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jie; Cai, Shifeng; Han, Xue; Liu, Qingwei; Xin, Yinghui [Shandong University, Department of Radiology, Shandong Provincial Hospital, Jinan (China); Li, Changzhong; Yang, Chunrun [Shandong University, Department of Obstetrics and Gynecology, Shandong Provincial Hospital, Jinan (China); Sun, Xichao; Zong, Yuanyuan [Shandong University, Department of Pathology, Shandong Provincial Hospital, Jinan (China); Fu, Caixia [Siemens Shenzhen Magnetic Resonance Ltd., Siemens MRI Center, Shenzhen (China)

    2014-10-15

    To investigate whether the choline-containing compounds (Cho) obtained from three-dimensional {sup 1}H magnetic resonance (MR) spectroscopy can differentiate endometrial cancer (ECa) from benign lesions in endometria or in submucosa (BLs-ESm) and is associated with the aggressiveness of ECa. Fifty-seven patients (ECa, 38; BLs-ESm, 19) underwent preoperative multi-voxel MR spectroscopy at 3.0 T. The ratio of the sum of the Cho peak integral to the sum of the unsuppressed water peak integral (Cho/water) and the coefficient of variation (CV) used to describe the variability of Cho/water in one lesion were calculated. Mean Cho/water (±standard deviation [SD]) was (3.02 ± 1.43) x 10{sup -3} for ECa and (1.68 ± 0.33) x 10{sup -3} for BLs-ESm (p < 0.001). Mean Cho/water was (4.42 ± 1.53) x 10{sup -3} for type II ECa and (2.65 ± 1.17) x 10{sup -3} for type I ECa (p = 0.001). There were no significant differences among different stages of ECa (p = 0.107) or different grades of ECa (p = 0.142). The Cho/water was positively correlated with tumour stage (r = 0.386, p = 0.017) and size (r = 0.333, p = 0.041). The CV was also positively correlated with tumour stage (r = 0.537, p = 0.001) and size (r = 0.34, p = 0.037). The Cho/water can differentiate ECa from BLs-ESm and differentiate type II from type I ECa, but cannot differentiate different stages of ECa or different grades of ECa. Cho/water increased with the increase of tumour stage and size. (orig.)

  4. Magnetic Resonance Imaging of Normal Pressure Hydrocephalus.

    Science.gov (United States)

    Bradley, William G

    2016-04-01

    Normal pressure hydrocephalus (NPH) is a syndrome found in the elderly, which is characterized by ventriculomegaly and deep white matter ischemia (DWMI) on magnetic resonance imaging (MRI) and the clinical triad of gait disturbance, dementia, and urinary incontinence. NPH has been estimated to account for up to 10% of cases of dementia and is significant because it is treatable by ventriculoperitoneal shunting. Patients with a known cause of chronic communicating hydrocephalus, that is, meningitis or hemorrhage, tend to respond better than patients with the so-called "idiopathic" form, most likely because of poor selection criteria in the past. Good response to shunting has been associated with hyperdynamic cerebrospinal fluid (CSF) flow through the aqueduct. In the early days of MRI, patients with a large CSF flow void extending from the foramen of Monro through the aqueduct to the fourth ventricle had an excellent chance of responding to ventriculoperitoneal shunting (P < 0.003). Today, we use phase-contrast MRI to measure the volume of CSF flowing through the aqueduct in either direction over a cardiac cycle. When this aqueductal CSF stroke volume is sufficiently elevated, there is an excellent chance of shunt responsiveness (100% positive predictive value in 1 study). Idiopathic NPH appears to be a "two-hit" disease-benign external hydrocephalus (BEH) in infancy followed by DWMI in late adulthood. As BEH occurs when the sutures are still open, these infants present with large heads, a finding also noted in patients with NPH. Although BEH has been attributed to immature arachnoidal granulations with decreased CSF resorptive capacity, this now appears to be permanent and may lead to a parallel pathway for CSF resorption via the extracellular space of the brain. With DWMI, the myelin lipid is lost, exposing the polar water molecules to myelin protein, increasing resistance to CSF outflow and leading to backing up of CSF and hydrocephalus. PMID:27063662

  5. Functional magnetic resonance imaging of the lung.

    Science.gov (United States)

    Biederer, J; Heussel, C P; Puderbach, M; Wielpuetz, M O

    2014-02-01

    Beyond being a substitute for X-ray, computed tomography, and scintigraphy, magnetic resonance imaging (MRI) inherently combines morphologic and functional information more than any other technology. Lung perfusion: The most established method is first-pass contrast-enhanced imaging with bolus injection of gadolinium chelates and time-resolved gradient-echo (GRE) sequences covering the whole lung (1 volume/s). Images are evaluated visually or semiquantitatively, while absolute quantification remains challenging due to the nonlinear relation of T1-shortening and contrast material concentration. Noncontrast-enhanced perfusion imaging is still experimental, either based on arterial spin labeling or Fourier decomposition. The latter is used to separate high- and low-frequency oscillations of lung signal related to the effects of pulsatile blood flow. Lung ventilation: Using contrast-enhanced first-pass perfusion, lung ventilation deficits are indirectly identified by hypoxic vasoconstriction. More direct but still experimental approaches use either inhalation of pure oxygen, an aerosolized contrast agent, or hyperpolarized noble gases. Fourier decomposition MRI based on the low-frequency lung signal oscillation allows for visualization of ventilation without any contrast agent. Respiratory mechanics: Time-resolved series with high background signal such as GRE or steady-state free precession visualize the movement of chest wall, diaphragm, mediastinum, lung tissue, tracheal wall, and tumor. The assessment of volume changes allows drawing conclusions on regional ventilation. With this arsenal of functional imaging capabilities at high spatial and temporal resolution but without radiation burden, MRI will find its role in regional functional lung analysis and will therefore overcome the sensitivity of global lung function analysis for repeated short-term treatment monitoring. PMID:24481761

  6. GEOCHEMICAL CONTROLS ON NUCLEAR MAGNETIC RESONANCE MEASUREMENTS

    International Nuclear Information System (INIS)

    Proton nuclear magnetic resonance (NMR) is used in the Earth Sciences as a means of obtaining information about the molecular-scale environment of fluids in porous geological materials. Laboratory experiments were conducted to advance our fundamental understanding of the link between the NMR response and the geochemical properties of geological materials. In the first part of this research project, we studied the impact of both the surface-area-to-volume ratio (S/V) of the pore space and the surface relaxivity on the NMR response of fluids in sand-clay mixtures. This study highlighted the way in which these two parameters control our ability to use NMR measurements to detect and quantify fluid saturation in multiphase saturated systems. The second part of the project was designed to explore the way in which the mineralogic form of iron, as opposed to simply the concentration of iron, affects the surface relaxation rate and, more generally, the NMR response of porous materials. We found that the magnitude of the surface relaxation rate was different for the various iron-oxide minerals because of changes in both the surface-area-to-volume ratio of the pore space, and the surface relaxivity. Of particular significance from this study was the finding of an anomalously large surface relaxivity of magnetite compared to that of the other iron minerals. Differences in the NMR response of iron minerals were seen in column experiments during the reaction of ferrihydrite-coated quartz sand with aqueous Fe(II) solutions to form goethite, lepidocrocite and magnetite; indicating the potential use of NMR as a means of monitoring geochemical reactions. The final part of the research project investigated the impact of heterogeneity, at the pore-scale, on the NMR response. This work highlighted the way in which the geochemistry, by controlling the surface relaxivity, has a significant impact on the link between NMR data and the microgeometry of the pore space.

  7. Research progress of magnetic resonance imaging contrast agents

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Magnetic resonance imaging (MRI) is a clinical diagnostic modality, which has become popular in hospitals around the world. Approximately 30% of MRI exams include the use of contrast agents. The research progress of the paramagnetic resonance imaging contrast agents was described briefly. Three important approaches in the soluble paramagnetic resonance imaging contrast agents design including nonionic, tissue-specific and macromolecular contrast agents were investigated. In addition, the problems in the research and development in future were discussed.

  8. Magnetic resonance velocimetry: applications of magnetic resonance imaging in the measurement of fluid motion

    Science.gov (United States)

    Elkins, Christopher J.; Alley, Marcus T.

    2007-12-01

    Magnetic resonance velocimetry (MRV) is a non-invasive technique capable of measuring the three-component mean velocity field in complex three-dimensional geometries with either steady or periodic boundary conditions. The technique is based on the phenomenon of nuclear magnetic resonance (NMR) and works in conventional magnetic resonance imaging (MRI) magnets used for clinical imaging. Velocities can be measured along single lines, in planes, or in full 3D volumes with sub-millimeter resolution. No optical access or flow markers are required so measurements can be obtained in clear or opaque MR compatible flow models and fluids. Because of its versatility and the widespread availability of MRI scanners, MRV is seeing increasing application in both biological and engineering flows. MRV measurements typically image the hydrogen protons in liquid flows due to the relatively high intrinsic signal-to-noise ratio (SNR). Nonetheless, lower SNR applications such as fluorine gas flows are beginning to appear in the literature. MRV can be used in laminar and turbulent flows, single and multiphase flows, and even non-isothermal flows. In addition to measuring mean velocity, MRI techniques can measure turbulent velocities, diffusion coefficients and tensors, and temperature. This review surveys recent developments in MRI measurement techniques primarily in turbulent liquid and gas flows. A general description of MRV provides background for a discussion of its accuracy and limitations. Techniques for decreasing scan time such as parallel imaging and partial k-space sampling are discussed. MRV applications are reviewed in the areas of physiology, biology, and engineering. Included are measurements of arterial blood flow and gas flow in human lungs. Featured engineering applications include the scanning of turbulent flows in complex geometries for CFD validation, the rapid iterative design of complex internal flow passages, velocity and phase composition measurements in

  9. Resonant Spin Wave Excitation by Terahertz Magnetic Near-field Enhanced with Split Ring Resonator

    CERN Document Server

    Mukai, Y; Yamamoto, T; Kageyama, H; Tanaka, K

    2014-01-01

    Excitation of antiferromagnetic spin waves in HoFeO$_{3}$ crystal combined with a split ring resonator (SRR) is studied using terahertz (THz) electromagnetic pulses. The magnetic field in the vicinity of the SRR induced by the incident THz electric field component excites and the Faraday rotation of the polarization of a near-infrared probe pulse directly measures oscillations that correspond to the antiferromagnetic spin resonance mode. The good agreement of the temperature-dependent magnetization dynamics with the calculation using the two-lattice Landau-Lifshitz-Gilbert equation confirms that the spin wave is resonantly excited by the THz magnetic near-field enhanced at the LC resonance frequency of the SRR, which is 20 times stronger than the incident magnetic field.

  10. Magnetic resonance imaging of tumor oxygenation and metabolic profile

    DEFF Research Database (Denmark)

    Krishna, Murali C.; Matsumoto, Shingo; Saito, Keita;

    2013-01-01

    an exogenous contrast agent: electron paramagnetic resonance imaging (EPRI) and Overhauser magnetic resonance imaging (OMRI). Tumor metabolic profile can be assessed by a third method, hyperpolarized metabolic MR, based on injection of hyperpolarized biological molecules labeled with 13C or 15N and MR...... which can characterize such features non-invasively and repeatedly will be of significant value in planning treatment as well as monitoring response to treatment. The three techniques based on magnetic resonance imaging (MRI) are reviewed here. Tumor pO2 can be measured by two MRI methods requiring...

  11. Automated data evaluation and modelling of simultaneous (19) F-(1) H medium-resolution NMR spectra for online reaction monitoring.

    Science.gov (United States)

    Zientek, Nicolai; Laurain, Clément; Meyer, Klas; Paul, Andrea; Engel, Dirk; Guthausen, Gisela; Kraume, Matthias; Maiwald, Michael

    2016-06-01

    Medium-resolution nuclear magnetic resonance spectroscopy (MR-NMR) currently develops to an important analytical tool for both quality control and process monitoring. In contrast to high-resolution online NMR (HR-NMR), MR-NMR can be operated under rough environmental conditions. A continuous re-circulating stream of reaction mixture from the reaction vessel to the NMR spectrometer enables a non-invasive, volume integrating online analysis of reactants and products. Here, we investigate the esterification of 2,2,2-trifluoroethanol with acetic acid to 2,2,2-trifluoroethyl acetate both by (1) H HR-NMR (500 MHz) and (1) H and (19) F MR-NMR (43 MHz) as a model system. The parallel online measurement is realised by splitting the flow, which allows the adjustment of quantitative and independent flow rates, both in the HR-NMR probe as well as in the MR-NMR probe, in addition to a fast bypass line back to the reactor. One of the fundamental acceptance criteria for online MR-MNR spectroscopy is a robust data treatment and evaluation strategy with the potential for automation. The MR-NMR spectra are treated by an automated baseline and phase correction using the minimum entropy method. The evaluation strategies comprise (i) direct integration, (ii) automated line fitting, (iii) indirect hard modelling (IHM) and (iv) partial least squares regression (PLS-R). To assess the potential of these evaluation strategies for MR-NMR, prediction results are compared with the line fitting data derived from the quantitative HR-NMR spectroscopy. Although, superior results are obtained from both IHM and PLS-R for (1) H MR-NMR, especially the latter demands for elaborate data pretreatment, whereas IHM models needed no previous alignment. Copyright © 2015 John Wiley & Sons, Ltd. PMID:25854892

  12. Terahertz Magnetic Mirror Realized with Dielectric Resonator Antennas.

    Science.gov (United States)

    Headland, Daniel; Nirantar, Shruti; Withayachumnankul, Withawat; Gutruf, Philipp; Abbott, Derek; Bhaskaran, Madhu; Fumeaux, Christophe; Sriram, Sharath

    2015-11-25

    Single-crystal silicon is bonded to a metal-coated substrate and etched in order to form an array of microcylinder passive terahertz dielectric resonator antennas (DRAs). The DRAs exhibit a magnetic response, and hence the array behaves as an efficient artificial magnetic conductor (AMC), with potential for terahertz antenna and sensing applications.

  13. The Nobel Prize in Medicine for Magnetic Resonance Imaging

    Science.gov (United States)

    Fry, Charles G.

    2004-01-01

    Nobel Prize in Medicine awarded in December 2003 to chemist Paul C. Lauterbur and physicist Peter Mansfield for the development of magnetic resonance imaging (MRI), a long overdue recognition of the huge impact MRI has had in medical diagnostics and research is mentioned. MRI was derived, and remains an extension of nuclear magnetic resonance…

  14. A Quantum Mechanical Review of Magnetic Resonance Imaging

    CERN Document Server

    Odaibo, Stephen G

    2012-01-01

    In this paper, we review the quantum mechanics of magnetic resonance imaging (MRI). We traverse its hierarchy of scales from the spin and orbital angular momentum of subatomic particles to the ensemble magnetization of tissue. And we review a number of modalities used in the assessment of acute ischemic stroke and traumatic brain injury.

  15. In vivo magnetic resonance spectroscopy: basic methodology and clinical applications.

    NARCIS (Netherlands)

    Graaf, M. van der

    2010-01-01

    The clinical use of in vivo magnetic resonance spectroscopy (MRS) has been limited for a long time, mainly due to its low sensitivity. However, with the advent of clinical MR systems with higher magnetic field strengths such as 3 Tesla, the development of better coils, and the design of optimized ra

  16. Parametric resonance induced chaos in magnetic damped driven pendulum

    Science.gov (United States)

    Khomeriki, Giorgi

    2016-07-01

    A damped driven pendulum with a magnetic driving force, appearing from a solenoid, where ac current flows is considered. The solenoid acts on the magnet, which is located at a free end of the pendulum. In this system the existence and interrelation of chaos and parametric resonance is theoretically examined. Derived analytical results are supported by numerical simulations and conducted experiments.

  17. Reactions (d,7Li) and (d,7Be) in 19F nuclei

    International Nuclear Information System (INIS)

    Differential cross sections have been measured for the reactions 19F(d,7Li)14N, 19F(d,7Li(/sub 0.478/)14N, 19F(d,7Be)14C, and 19F(d,7Be(/sub 0.429/)14C in a cyclotron beam of deuterons with energy 13.6 MeV. The experimental data were analyzed by the distorted-wave method with inclusion of the finite interaction range and recoil. It is shown that the reactiuns 19F(d,7Li)14N and 19F(d,7Li(/sub 0.478/)14N occur mainly by direct transfer of a 5He cluster from the 4P/sub 1/2/ state of the 19F nucleus to the 1D/sub 3/2/ state of the 7Li nucleus. The differential cross sections for the reactions 19F(d,7Be)14C and 19F(d,7Be(/sub 0.429/)14C could not be explained in terms of the theory of direct transfer of a 5Li cluster

  18. Radiation dosimetry using magnetic resonance imaging

    International Nuclear Information System (INIS)

    A new dosimetry system for 3D dose distribution measurements based on the Fricke dosimeter and magnetic resonance imaging (MRI) has been developed. The dosimeter consists of a ferrous sulphate solution incorporated in an agarose gel, which together constitute the dosimeter gel. The absorbed dose to the gel is measured by means of the proton spin-lattice relaxation rate, 1/T1 in an MR scanner. The dose distribution to an arbitrary slice within a dosimeter gel phantom can thus be determined. The chemical yield of the dosimeter gel is significantly higher than that of the for Fricke solution, and is strongly dependent of the initial ferrous sulphate concentration, assuming that the gel is bubbled with oxygen during preparation. A gel of 1.5 mM [Fe2+] and 50 mM [H2SO4] has a sensitivity of 0.108 s-1Gy-1 and is linear up to 50 Gy. The dosimeter gel has uniform dose response over large volumes. Above 50 mM[H2SO4] the yield increases only slightly, but the gel strength decreases and results in gel phantoms with non-uniform dose response. Below 50 mM[H2SO4] the sensitivity of the dosimeter falls rapidly due to the decreased relaxivity of the ferric ions. The high chemical yield can be explained by a chain reaction and a reaction scheme is accordingly proposed. The dosimeter gel shows no dependence on dose rate or radiation quality and can be regarded as water-equivalent with respect to the interaction of the radiation. The diffusion coefficient of the ferric ions in the agarose gel is 1.19x10-2 cm2/h. The diffusion blurs the dosimeteric image, but poses only a minor problem if the MR measurements are completed within the first two hours after irradiation. Dose distribution data from external radiation therapy units have been determined using the dosimeter gel and MRI with good accuracy, but the precision is poor, about 5-10%. (au) (84 refs.)

  19. Tools and methods for teaching magnetic resonance concepts and techniques

    DEFF Research Database (Denmark)

    Hanson, Lars G.

    2012-01-01

    Teaching of MRI methodology can be challenging for teachers as well as students. To support student learning, two graphical simulators for exploration of basic magnetic resonance principles are here introduced. The first implements a simple compass needle analogy implemented for day one of NMR...... and MRI education. After a few minutes of use, any user with minimal experience of magnetism will be able to explain the basic magnetic resonance principle. A second piece of software, the Bloch Simulator, aims much further, as it can be used to demonstrate and explore a wide range of phenomena including...

  20. A Spectral-Scanning Magnetic Resonance Imaging (MRI) Integrated System

    OpenAIRE

    Hassibi, Arjang; Babakhani, Aydin; Hajimiri, Ali

    2008-01-01

    An integrated spectral-scanning magnetic resonance imaging (MRI) technique is implemented in a 0.12μm SiGe BiCMOS process. This system is designed for small-scale MRI applications with non-uniform and low magnetic fields. The system is capable of generating customized magnetic resonance (MR) excitation signals, and also recovering the MR response using a coherent direct conversion receiver. The operation frequency is tunable from DC to 37MHz for wide-band MRI and up to...

  1. Three-Tesla magnetic resonance elastography for hepatic fibrosis: Comparison with diffusion-weighted imaging and gadoxetic acid-enhanced magnetic resonance imaging

    OpenAIRE

    Park, Hee Sun; Kim, Young Jun; Yu, Mi Hye; Choe, Won Hyeok; Jung, Sung Il; Jeon, Hae Jeong

    2014-01-01

    AIM: To evaluate the feasibility of 3-Tesla magnetic resonance elastography (MRE) for hepatic fibrosis and to compare that with diffusion-weighted imaging (DWI) and gadoxetic acid-enhanced magnetic resonance (MR) imaging.

  2. Tunable resonant transmission of electromagnetic waves through a magnetized plasma.

    Science.gov (United States)

    Kee, Chul-Sik; Li, Shou-Zhe; Kim, Kihong; Lim, H

    2003-03-01

    We theoretically investigate the resonant transmission of circularly polarized electromagnetic waves in the electromagnetic stop band of a magnetized plasma slab using the invariant embedding method. The frequency and quality factor of the resonant mode for the right-handed (left-handed) circularly polarized wave created by inserting a dielectric layer into the plasma increase (decrease) as the magnitude of the external magnetic field increases. These phenomena are compared with the characteristics of resonant modes in metallic and dielectric Fabry-Perot resonators to show that they are due to the change of plasma reflectivity. We also discuss the damping effect due to the collisions of the constituent particles of the plasma on the resonant transmission of circularly polarized waves. PMID:12689184

  3. Magnetic resonance enteroclysis: state of the art

    International Nuclear Information System (INIS)

    Full text: Magnetic Resonance Imaging (MRI) possess several virtues including superb soft-tissue contrast, absence of radiation exposure, cross-sectional and projectional imaging capabilities in all three dimensions and multiple contrast sources, that may favour a comprehensive morphologic and functional evaluation of the small bowel (SB). Ultrafast pulse sequences should be utilized to reduce motion related artifacts arising from physiological motion (respiration and peristalsis). the spatial resolution of these sequences should be high enough to permit demonstration of small lesions i.e. ulcers, that are usually present in small bowel diseases. MRI examination protocols of the small bowel usually comprise T1- and T2- weighted sequences on axial and coronal planes. Both T1- and T2- weighted sequences should be fast enough to allow comfortable breath-hold acquisition times and reduce the motion related artifacts. For T1- weighted images, most authors are using gradient echo sequences in 2D and 3D acquisition modes with or without fat saturation prepulses, while for T2-weighted images, TCE and HASTE sequences are commonly employed. True FISP sequence has been successfully applied in SB imaging, providing high resolution images of the bowel wall and additional information from the mesenteries. Fat suppressed TSE or STIR sequences have been also applied to access Crohn disease activity. True FISP sequence was introduced for MR examination of the small bowel after duodenal intubation. the contrast in true FISP images is somewhat more complex and invoke both T1 and T2 contributions in the form of the T2/T1 ratio. True FISP sequence is excellent in demonstrating the mesenteries, due to high contrast resolution between the bright peritoneal fat and the dark vessels and lymph nodes. Motion related artifacts are minimal on true FISP images due to short acquisition time. As opposed to HASTE sequences, true FISP is insensitive to intraluminal flow voids, due to its balanced

  4. Spin microscope based on optically detected magnetic resonance

    Science.gov (United States)

    Berman, Gennady P.; Chernobrod, Boris M.

    2007-12-11

    The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of unpaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.

  5. Quantum transport in coupled resonators enclosed synthetic magnetic flux

    Science.gov (United States)

    Jin, L.

    2016-07-01

    Quantum transport properties are instrumental to understanding quantum coherent transport processes. Potential applications of quantum transport are widespread, in areas ranging from quantum information science to quantum engineering, and not restricted to quantum state transfer, control and manipulation. Here, we study light transport in a ring array of coupled resonators enclosed synthetic magnetic flux. The ring configuration, with an arbitrary number of resonators embedded, forms a two-arm Aharonov-Bohm interferometer. The influence of magnetic flux on light transport is investigated. Tuning the magnetic flux can lead to resonant transmission, while half-integer magnetic flux quantum leads to completely destructive interference and transmission zeros in an interferometer with two equal arms.

  6. Magnetic Resonance Imaging and Magnetic Resonance Spectroscopy Characterize a Rodent Model of Covert Stroke

    Science.gov (United States)

    Herrera, Sheryl Lyn

    Covert stroke (CS) comprises lesions in the brain often associated by risk factors such as a diet high in fat, salt, cholesterol and sugar (HFSCS). Developing a rodent model for CS incorporating these characteristics is useful for developing and testing interventions. The purpose of this thesis was to determine if magnetic resonance (MR) can detect brain abnormalities to confirm this model will have the desired anatomical effects. Ex vivo MR showed brain abnormalities for rats with the induced lesions and fed the HFSCS diet. Spectra acquired on the fixed livers had an average percent area under the fat peak relative to the water peak of (20+/-4)% for HFSCS and (2+/-2)% for control. In vivo MR images had significant differences between surgeries to induce the lesions (p=0.04). These results show that applying MR identified abnormalities in the rat model and therefore is important in the development of this CS rodent model.

  7. Rotational characteristics in the resonance state of the HTSC-permanent magnet hybrid magnetic bearing

    International Nuclear Information System (INIS)

    The hybrid magnetic bearing has been developed. In the hybrid system, effect of the pinning force becomes smaller. Influence of the vibration and the gradient angle in the resonance state is large. The resonance frequency becomes small in the hybrid bearing system. The hybrid magnetic bearing using permanent magnets and the high-Tc bulk superconductor (HTSC) has been developed. Repulsive force of the permanent magnet is introduced to increase the load weight of the magnetic bearing. Effect of the hybrid system has been shown. In this paper, influence of the hybrid system on the dynamic characteristics of the rotor is studied. The rotational characteristics in the mechanical resonance state are studied, and the equivalent magnetic spring coefficient is estimated from the experimental results of the load weight. The resonance frequency is measured by the rotation experiments. The rotor achieves stable levitation even in the resonance state. In the hybrid system, effect of the pinning force becomes smaller than that of the lateral force generated by the repulsive force between the two permanent magnets at the smaller air gap. Thus influence of the lateral vibration and the gradient angle in the resonance state becomes larger at a smaller air gap. The equivalent magnetic spring coefficient becomes also small, and the resonance frequency becomes small in the hybrid bearing system.

  8. Rotational characteristics in the resonance state of the HTSC-permanent magnet hybrid magnetic bearing

    Energy Technology Data Exchange (ETDEWEB)

    Morii, Y.; Sukedai, M. [Kansai University, 3-3-35 Yamate-cho, Suita, Osaka 564-8680 (Japan); Ohashi, S., E-mail: ohashi@kansai-u.ac.jp [Kansai University, 3-3-35 Yamate-cho, Suita, Osaka 564-8680 (Japan)

    2011-11-15

    The hybrid magnetic bearing has been developed. In the hybrid system, effect of the pinning force becomes smaller. Influence of the vibration and the gradient angle in the resonance state is large. The resonance frequency becomes small in the hybrid bearing system. The hybrid magnetic bearing using permanent magnets and the high-Tc bulk superconductor (HTSC) has been developed. Repulsive force of the permanent magnet is introduced to increase the load weight of the magnetic bearing. Effect of the hybrid system has been shown. In this paper, influence of the hybrid system on the dynamic characteristics of the rotor is studied. The rotational characteristics in the mechanical resonance state are studied, and the equivalent magnetic spring coefficient is estimated from the experimental results of the load weight. The resonance frequency is measured by the rotation experiments. The rotor achieves stable levitation even in the resonance state. In the hybrid system, effect of the pinning force becomes smaller than that of the lateral force generated by the repulsive force between the two permanent magnets at the smaller air gap. Thus influence of the lateral vibration and the gradient angle in the resonance state becomes larger at a smaller air gap. The equivalent magnetic spring coefficient becomes also small, and the resonance frequency becomes small in the hybrid bearing system.

  9. Duffing oscillation-induced reversal of magnetic vortex core by a resonant perpendicular magnetic field

    OpenAIRE

    Kyoung-Woong Moon; Byong Sun Chun; Wondong Kim; Qiu, Z. Q.; Chanyong Hwang

    2014-01-01

    Nonlinear dynamics of the magnetic vortex state in a circular nanodisk was studied under a perpendicular alternating magnetic field that excites the radial modes of the magnetic resonance. Here, we show that as the oscillating frequency is swept down from a frequency higher than the eigenfrequency, the amplitude of the radial mode is almost doubled to the amplitude at the fixed resonance frequency. This amplitude has a hysteresis vs. frequency sweeping direction. Our result showed that this p...

  10. Dysembryoplastic neuroepithelial tumors: magnetic resonance imaging and magnetic resonance spectroscopy evaluation

    Institute of Scientific and Technical Information of China (English)

    YU Ai-hong; CHEN Li; LI Yong-jie; ZHANG Guo-jun; LI Kun-cheng; WANG Yu-ping

    2009-01-01

    Background Dysembryoplastic neuroepithelial tumor (DNT) is a rare benign neoplasm of the central nervous system affecting young people. A correct preoperative diagnosis is helpful for planning surgical strategies and improving prognosis. The purpose of this study was to characterize DNTs using magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) and to analyze the value of these two techniques in the diagnosis of DNTs.Methods MR images of 13 patients with DNTs were reviewed retrospectively; and five of the patients also underwent MRS. Tumors were confirmed by surgery. The distribution, extension and signal features of the lesions were assessed,and the MRS results were analyzed.Results All tumors were supratentorial. The cortex was the main area involved, with nine tumors located in the temporal lobe, three in the frontal lobe, and one on the boundary between the temporal and occipital lobes. All cases had decreased signal intensity on T1-weighted MR images and increased signal intensity on T2-weighted images. On fluid attenuated inversion recovery weighted images, the hyperintense "ring sign" and internal septation of the lesion were seen in 9 cases. Eight tumors had well-demarcated borders. Peritumoral edema or mass effect was absent in all cases. A contrast enhancement examination was performed in 9 cases. Contrast enhancement was absent in five cases, and four cases showed significant enhancement. The MRS showed a low N-acetylaspartate peak and a lack of elevated choline-containing component (Cho) or Cho-Cr ratio (Cho/Cr) in five patients.Conclusions The MRI findings of DNTs were stereotypical. The combination of MRI and MRS techniques were helpful in making a correct presurgical diagnosis.

  11. Chronic hepatosplenic schistosomiasis mansoni: magnetic resonance imaging and magnetic resonance angiography findings

    Energy Technology Data Exchange (ETDEWEB)

    Bezerra, A.S.; D' Ippolito, G.; Caldana, R.P.; Cecin, A.O.; Ahmed, M.; Szejnfeld, J. [Dept. of Diagnostic Imaging, Federal Univ. of Sao Paulo, Sao Paulo (Brazil)

    2007-02-15

    Purpose: To evaluate the hepatosplenic manifestations and the portal venous system in patients with chronic infection by Schistosoma mansoni. Material and Methods: A cross-sectional observational study was performed in 28 patients with chronic hepatosplenic schistosomiasis submitted to magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) of the abdomen. Images were interpreted independently by two radiologists to determine the reproducibility of image interpretation and who evaluated the presence of morphological alterations in the liver and spleen, such as hepatosplenomegaly, hepatic fissure widening, periportal fibrosis, and the presence of siderotic nodules. Interobserver and intra-observer agreement were measured with the kappa and intraclass correlation tests. Evaluation of venous collateral pathways and portal and splenic veins was done in consensus by both examiners. Results: Observers identified enlargement of the left lobe (78.5-92.8%) and caudate-to-right-lobe ratio (78.5-92.8%), irregularity of hepatic contours (89.2-96.4%), fissure widening (89.2-100%), and splenic siderotic nodules (84.2%). Splenomegaly, heterogeneity of hepatic parenchyma, peripheral hepatic vessels, and periportal fibrosis were observed in 100% of patients. MRI findings presented almost perfect interobserver (kappa 0.65-1) and intra-observer (kappa = 0.73-1 for observer 1, and kappa = 0.65-1 for observer 2) agreement for the variables analyzed. MRA showed the presence of collateral pathways in the majority of patients (71.4%) along with widening of portal and splenic veins. Conclusion: Using MRI, hepatosplenic alterations in schistosomiasis are characterized by heterogeneity of hepatic parenchyma, presence of peripheral perihepatic vessels, periportal fibrosis, splenomegaly, siderotic nodules, and the presence of venous collateral pathways.

  12. Comparison of nuclear electric resonance and nuclear magnetic resonance in integer and fractional quantum Hall states

    International Nuclear Information System (INIS)

    Electric-field-induced nuclear resonance (NER: nuclear electric resonance) involving quantum Hall states (QHSs) was studied at various filling factors by exploiting changes in nuclear spins polarized at quantum Hall breakdown. Distinct from the magnetic dipole interaction in nuclear magnetic resonance, the interaction of the electric-field gradient with the electric quadrupole moment plays the dominant role in the NER mechanism. The magnitude of the NER signal strongly depends on whether electronic states are localized or extended. This indicates that NER is sensitive to the screening capability of the electric field associated with QHSs

  13. Comparison of nuclear electric resonance and nuclear magnetic resonance in integer and fractional quantum Hall states

    Directory of Open Access Journals (Sweden)

    Toru Tomimatsu

    2015-08-01

    Full Text Available Electric-field-induced nuclear resonance (NER: nuclear electric resonance involving quantum Hall states (QHSs was studied at various filling factors by exploiting changes in nuclear spins polarized at quantum Hall breakdown. Distinct from the magnetic dipole interaction in nuclear magnetic resonance, the interaction of the electric-field gradient with the electric quadrupole moment plays the dominant role in the NER mechanism. The magnitude of the NER signal strongly depends on whether electronic states are localized or extended. This indicates that NER is sensitive to the screening capability of the electric field associated with QHSs.

  14. Self-Assembly of Peptide Amphiphiles Designed as Imaging Probes for 19F and Relaxation-Enhanced 1H imaging

    Science.gov (United States)

    Preslar, Adam Truett

    This work incorporates whole-body imaging functionality into peptide amphiphile (PA) nanostructures used for regenerative medicine to facilitate magnetic resonance imaging (MRI). Two strategies were employed: 1. Conjugation of gadolinium chelates to peptide nanostructures to monitor biomaterial degradation in vivo with MRI and inductively-coupled plasma-mass spectroscopy (ICP-MS) 2. Synthesis of perfluorinated moiety-bearing peptide amphiphiles for 19F-MRI. The Gd(III) chelate gadoteridol was conjugated by copper-catalyzed "click" chemistry to a series of PAs known to form cylindrical nanostructures. By fitting nuclear magnetic resonance dispersion (NMRD) profiles to the Solomon-Bloembergen-Morgan (SBM) equations, it was observed that the water exchange parameter (tauM) depended on thermal annealing or calcium ion cross-linking. The sequence C16V 3A3E3G(Gd) exhibited an acceleration of nearly 100 ns after thermal annealing and calcium addition. These gadolinium-labeled PAs were used to track in vivo degradation of gels within the tibialis anterior muscle in a murine model. The half-life of biomaterial degradation was determined to be 13.5 days by inductively coupled plasma mass spectrometry (ICP-MS) of Gd(III). Gel implants could be monitored by MRI for eight days before the signal dispersed due to implant degradation and dilution. Additionally, nanostructures incorporating highly fluorinated domains were investigated for use as MRI contrast agents. Short, perfluoroalkyane tails of seven or eight carbon atoms in length were grafted to PA sequences containing a V2A2 beta-sheet forming sequence. The V2A2 sequence is known to drive 1D nanostructure assembly. It was found that the sequences C7F13V2A 2E2 and C7F13V2A 2K3 formed 1D assemblies in water which transition from ribbon-like to cylindrical shape as pH increases from 4.5 to 8.0. Ribbon-like nanostructures had reduced magnetic resonance signal by T 2 relaxation quenching, whereas their cylindrical counterparts

  15. Three-dimensional magnetic recording using ferromagnetic resonance

    Science.gov (United States)

    Suto, Hirofumi; Kudo, Kiwamu; Nagasawa, Tazumi; Kanao, Taro; Mizushima, Koichi; Sato, Rie

    2016-07-01

    To meet the ever-increasing demand for data storage, future magnetic recording devices will need to be made three-dimensional by implementing multilayer recording. In this article, we present methods of detecting and manipulating the magnetization direction of a specific layer selectively in a vertically stacked multilayer magnetic system, which enable layer-selective read and write operations in three-dimensional magnetic recording devices. The principle behind the methods is ferromagnetic resonance excitation in a microwave magnetic field. By designing each magnetic recording layer to have a different ferromagnetic resonance frequency, magnetization excitation can be induced individually in each layer by tuning the frequency of an applied microwave magnetic field, and this selective magnetization excitation can be utilized for the layer-selective operations. Regarding media for three-dimensional recording, when layers of a perpendicular magnetic material are vertically stacked, dipolar interaction between multiple recording layers arises and is expected to cause problems, such as degradation of thermal stability and switching field distribution. To solve these problems, we propose the use of an antiferromagnetically coupled structure consisting of hard and soft magnetic layers. Because the stray fields from these two layers cancel each other, antiferromagnetically coupled media can reduce the dipolar interaction.

  16. Magnetic resonance imaging in the evaluation of periosteal reactions

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira-Barbosa, Marcello Henrique; Trad, Clovis Simao; Muglia, Valdair Francisco; Elias Junior, Jorge; Simao, Marcelo Novelino, E-mail: marcello@fmrp.usp.b [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Centro de Ciencias das Imagens e Fisica Medica; Sa, Jose Luiz de [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Hospital das Clinicas; Oliveira, Rodrigo Cecilio Vieira de [Clinica de Diagnostico por Imagem Tomoson, Aracatuba, SP (Brazil); Engel, Edgard Eduard [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Dept. de Biomecanica, Medicina e Reabilitacao do Aparelho Locomotor

    2010-07-15

    The objective of the present essay was to encourage a careful evaluation of periosteal reactions on magnetic resonance images. The initial approach to bone lesions is made by conventional radiography and, based on the imaging findings, periosteal reactions are classified into classical subtypes. Although magnetic resonance imaging is considered as the gold standard for local staging of bone tumors, the utilization of such method in the study of periosteal reactions related to focal bone lesions has been poorly emphasized, with relatively few studies approaching this subject. The literature review revealed a study describing an experimental animal model of osteomyelitis suggesting that magnetic resonance imaging is superior to other imaging methods in the early identification of periosteal reactions. Another study has suggested a good correlation between conventional radiography and magnetic resonance imaging in the identification and classification of periosteal reactions in cases of osteosarcoma. The present essay illustrates cases of periosteal reactions observed at magnetic resonance imaging in correlation with findings of conventional radiography or other imaging methods. (author)

  17. Magnetic Resonance Imaging Studies of Postpartum Depression: An Overview

    Directory of Open Access Journals (Sweden)

    Marco Fiorelli

    2015-01-01

    Full Text Available Postpartum depression is a frequent and disabling condition whose pathophysiology is still unclear. In recent years, the study of the neural correlates of mental disorders has been increasingly approached using magnetic resonance techniques. In this review we synthesize the results from studies on postpartum depression in the context of structural, functional, and spectroscopic magnetic resonance studies of major depression as a whole. Compared to the relative wealth of data available for major depression, magnetic resonance studies of postpartum depression are limited in number and design. A systematic literature search yielded only eleven studies conducted on about one hundred mothers with postpartum depression overall. Brain magnetic resonance findings in postpartum depression appear to replicate those obtained in major depression, with minor deviations that are not sufficient to delineate a distinct neurobiological profile for this condition, due to the small samples used and the lack of direct comparisons with subjects with major depression. However, it seems reasonable to expect that studies conducted in larger populations, and using a larger variety of brain magnetic resonance techniques than has been done so far, might allow for the identification of neuroimaging signatures for postpartum depression.

  18. Resonance magnetic x-ray scattering study of erbium

    DEFF Research Database (Denmark)

    Sanyal, M.K.; Gibbs, D.; Bohr, J.;

    1994-01-01

    of this magnetic scattering and analyzed it using a simple model based on electric dipole and quadrupole transitions among atomic orbitals. The line shapes can be fitted to a magnetic structure combining both c-axis-modulated and basal-plane components. Below 18 K, we have observed unusual behavior......The magnetic phases of erbium have been studied by resonance x-ray-scattering techniques. When the incident x-ray energy is tuned near the L(III) absorption edge, large resonant enhancements of the magnetic scattering are observed above 18 K. We have measured the energy and polarization dependence...... of the magnetic scattering as a function of energy, whose origin is not understood....

  19. Introduction to magnetic resonance and its application to dipole magnet testing

    International Nuclear Information System (INIS)

    An introduction to the features of magnetic resonance that are essential for understanding its application to testing accelerator dipole magnets is presented, including the accuracy that can be expected in field measurements and the factors that limit it. The use of an array of coils to measure the multipole moments of dipole magnets is discussed

  20. Quantitative 19F MR spectroscopy at 3 T to detect heterogeneous capecitabine metabolism in human liver.

    NARCIS (Netherlands)

    Klomp, D.W.J.; Laarhoven, H.W.M. van; Scheenen, T.W.J.; Kamm, Y.J.L.; Heerschap, A.

    2007-01-01

    Chemotherapy in non-responding cancer patients leads to unnecessary toxicity. A marker is therefore required that can predict the sensitivity of a specific tumour to chemotherapy, which would enable individualisation of therapy. 19F MR spectroscopy (19F MRS) can be used to monitor the metabolism of

  1. Current-induced spin torque resonance of a magnetic insulator

    Science.gov (United States)

    Schreier, Michael; Chiba, Takahiro; Niedermayr, Arthur; Lotze, Johannes; Huebl, Hans; Geprägs, Stephan; Takahashi, Saburo; Bauer, Gerrit E. W.; Gross, Rudolf; Goennenwein, Sebastian T. B.

    2015-10-01

    We report the observation of current-induced spin torque resonance in yttrium iron garnet/platinum bilayers. An alternating charge current at GHz frequencies in the platinum gives rise to dc spin pumping and spin Hall magnetoresistance rectification voltages, induced by the Oersted fields of the ac current and the spin Hall effect-mediated spin transfer torque. In ultrathin yttrium iron garnet films, we observe spin transfer torque actuated magnetization dynamics which are significantly larger than those generated by the ac Oersted field. Spin transfer torques thus efficiently couple charge currents and magnetization dynamics also in magnetic insulators, enabling charge current-based interfacing of magnetic insulators with microwave devices.

  2. Resonant Landau–Zener transitions in a helical magnetic field

    International Nuclear Information System (INIS)

    Spin-dependent electron transport has been studied in magnetic semiconductor waveguides (nanowires) in the helical magnetic field. We have shown that—apart from the well-known conductance dip located at the magnetic field equal to the helical-field amplitude Bh—the additional conductance dips (with zero conductance) appear at a magnetic field different from Bh. This effect occurring in the non-adiabatic regime is explained as resulting from the resonant Landau–Zener transitions between the spin-split subbands. (paper)

  3. Magnetic anisotropy of polycrystalline magnetoferritin investigated by SQUID and electron magnetic resonance

    Science.gov (United States)

    Moro, F.; de Miguel, R.; Jenkins, M.; Gómez-Moreno, C.; Sells, D.; Tuna, F.; McInnes, E. J. L.; Lostao, A.; Luis, F.; van Slageren, J.

    2014-06-01

    Magnetoferritin molecules with an average inorganic core diameter of 5.7±1.6 nm and polycrystalline internal structure were investigated by a combination of transmission electron microscopy, magnetic susceptibility, magnetization, and electron magnetic resonance (EMR) experiments. The temperature and frequency dependence of the magnetic susceptibility allowed for the determination of the magnetic anisotropy on an experimental time scale which spans from seconds to nanoseconds. In addition, angle-dependent EMR experiments were carried out for the determination of the nanoparticle symmetry and internal magnetic field. Due to the large surface to volume ratio, the nanoparticles show larger and uniaxial rather than cubic magnetic anisotropies compared to bulk maghemite and magnetite.

  4. On-wafer magnetic resonance of magnetite nanoparticles

    Science.gov (United States)

    Little, Charles A. E.; Russek, Stephen E.; Booth, James C.; Kabos, Pavel; Usselman, Robert J.

    2015-11-01

    Magnetic resonance measurements of ferumoxytol and TEMPO were made using an on-wafer transmission line technique with a vector network analyzer, allowing for broadband measurements of small sample volumes (4 nL) and small numbers of spins (1 nmol). On-wafer resonance measurements were compared with standard single-frequency cavity-based electron paramagnetic resonance (EPR) measurements using a new power conservation approach and the results show similar line shape. On-wafer magnetic resonance measurements using integrated microfluidics and microwave technology can significantly reduce the cost and sample volumes required for EPR spectral analysis and allow for integration of EPR with existing lab-on-a-chip processing and characterization techniques for point-of-care medical diagnostic applications.

  5. On-wafer magnetic resonance of magnetite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Little, Charles A.E., E-mail: caelittle@gmail.com; Russek, Stephen E., E-mail: stephen.russek@nist.gov; Booth, James C., E-mail: james.booth@nist.gov; Kabos, Pavel, E-mail: pavel.kabos@nist.gov; Usselman, Robert J., E-mail: robertusselman@gmail.com

    2015-11-01

    Magnetic resonance measurements of ferumoxytol and TEMPO were made using an on-wafer transmission line technique with a vector network analyzer, allowing for broadband measurements of small sample volumes (4 nL) and small numbers of spins (1 nmol). On-wafer resonance measurements were compared with standard single-frequency cavity-based electron paramagnetic resonance (EPR) measurements using a new power conservation approach and the results show similar line shape. On-wafer magnetic resonance measurements using integrated microfluidics and microwave technology can significantly reduce the cost and sample volumes required for EPR spectral analysis and allow for integration of EPR with existing lab-on-a-chip processing and characterization techniques for point-of-care medical diagnostic applications. - Highlights: • On-wafer measurements showed similar line shape to traditional cavity-based EPR. • New power conservation approach alleviates de-embedding ambiguities. • Allows for measurements of small sample volumes and small number of spins.

  6. Magnetic Barkhausen noise measurement by resonant coil method

    Energy Technology Data Exchange (ETDEWEB)

    Capo-Sanchez, J. [Departamento de Fisica, Facultad de Ciencias Naturales, Universidad de Oriente, Av. Patricio Lumumba s/n, 90500 Santiago de Cuba (Cuba)], E-mail: jcapo@usp.br; Padovese, L. [Departamento de Engenharia Mecanica, Escola Politecnica, Universidade de Sao Paulo, Av. Prof. Mello Moraes, 2231, 05508-900 Sao Paulo (Brazil)

    2009-09-15

    This paper describes a powerful new technique for nondestructive evaluation of ferromagnetic material. A method has been developed for measuring magnetic Barkhausen signals under different coil resonance frequencies. The measurements allow one to establish the behavior relating the power spectral density maximum and the resonant coil frequency. Time-frequency analysis of Barkhausen signals puts in evidence the tuning regions for each coil, and allows clear identification of each contribution to the Barkhausen signal spectrum. This concept was used in order to evaluate the relation between the degree of plastic deformation in carbon steel samples, and the power spectral density maximum at different resonance frequencies. This result also makes it possible to the selectively modify measurement sensibility to the magnetic Barkhausen signal by using different resonance frequencies.

  7. Magnetic hysteresis effects in superconducting coplanar microwave resonators

    Energy Technology Data Exchange (ETDEWEB)

    Bothner, D.; Gaber, T.; Kemmler, M.; Gruenzweig, M.; Ferdinand, B.; Koelle, D.; Kleiner, R. [Universitaet Tuebingen (Germany); Wuensch, S.; Siegel, M. [Karlsruher Institut fuer Technologie (Germany); Mikheenko, P.; Johansen, T.H. [University of Oslo (Norway)

    2013-07-01

    We present experimental data regarding the impact of external magnetic fields on quality factor and resonance frequency of superconducting microwave resonators in a coplanar waveguide geometry. In particular we focus on the influence of magnetic history and show with the assistance of numerical calculations that the found hysteretic behaviour can be well understood with a highly inhomogeneous microwave current density in combination with established field penetration models for type-II superconducting thin films. Furthermore we have used magneto-optical imaging techniques to check the field distribution which we have assumed in our calculations. Finally, we demonstrate that and how the observed hysteretic behaviour can be used to optimize and tune the resonator performance for possible hybrid quantum sytems in magnetic fields.

  8. Imaging using long range dipolar field effects Nuclear magnetic resonance

    CERN Document Server

    Gutteridge, S

    2002-01-01

    The work in this thesis has been undertaken by the except where indicated in reference, within the Magnetic Resonance Centre, at the University of Nottingham during the period from October 1998 to March 2001. This thesis details the different characteristics of the long range dipolar field and its application to magnetic resonance imaging. The long range dipolar field is usually neglected in nuclear magnetic resonance experiments, as molecular tumbling decouples its effect at short distances. However, in highly polarised samples residual long range components have a significant effect on the evolution of the magnetisation, giving rise to multiple spin echoes and unexpected quantum coherences. Three applications utilising these dipolar field effects are documented in this thesis. The first demonstrates the spatial sensitivity of the signal generated via dipolar field effects in structured liquid state samples. The second utilises the signal produced by the dipolar field to create proton spin density maps. Thes...

  9. Clinical software VIII for magnetic resonance imaging systems

    Energy Technology Data Exchange (ETDEWEB)

    Kohno, Satoru; Takeo, Kazuhiro [Medical Applications Department, Medical Systems Division, Shimadzu Corporation, Kyoto (Japan)

    2001-02-01

    This report describes the latest techniques of MRA (magnetic resonance angiography) and the brain attack diagnosis protocol which are now effectively utilized in the Shimadzu-Marconi MAGNEX ECLIPSE MRI (magnetic resonance imaging) system (1.5 tesla type) and the MAGNEX POLARIS MRI system (1.0 tesla type). As for the latest techniques for MRA, this report refers to the SLINKY (sliding interleaved ky) technique, which provides high-resolution images over a wide range in the direction of slice, without using contrast agent, and to the iPass technique which enables highly reliable CE-MRA (contrast-enhanced magnetic resonance angiography), through easy and simple operation. Also reported are the techniques of diffusion imaging and perfusion imaging, utilized for stroke assessment. (author)

  10. Magnetic resonance spectroscopy and imaging for the study of fossils.

    Science.gov (United States)

    Giovannetti, Giulio; Guerrini, Andrea; Salvadori, Piero A

    2016-07-01

    Computed tomography (CT) has long been used for investigating palaeontological specimens, as it is a nondestructive technique which avoids the need to dissolve or ionize the fossil sample. However, magnetic resonance spectroscopy (MRS) and magnetic resonance imaging (MRI) have recently gained ground as analytical tools for examination of palaeontological samples, by nondestructively providing information about the structure and composition of fossils. While MRI techniques are able to reveal the three-dimensional geometry of the trace fossil, MRS can provide information on the chemical composition of the samples. The multidimensional nature of MR (magnetic resonance) signals has potential to provide rich three-dimensional data on the palaeontological specimens and also to help in elucidating paleopathological and paleoecological questions. In this work the verified applications and the emerging uses of MRI and MRS in paleontology are reviewed, with particular attention to fossil spores, fossil plants, ambers, fossil invertebrates, and fossil vertebrate studies. PMID:26979538

  11. Biological effects of exposure to magnetic resonance imaging: an overview

    Directory of Open Access Journals (Sweden)

    Formica Domenico

    2004-04-01

    Full Text Available Abstract The literature on biological effects of magnetic and electromagnetic fields commonly utilized in magnetic resonance imaging systems is surveyed here. After an introduction on the basic principles of magnetic resonance imaging and the electric and magnetic properties of biological tissues, the basic phenomena to understand the bio-effects are described in classical terms. Values of field strengths and frequencies commonly utilized in these diagnostic systems are reported in order to allow the integration of the specific literature on the bio-effects produced by magnetic resonance systems with the vast literature concerning the bio-effects produced by electromagnetic fields. This work gives an overview of the findings about the safety concerns of exposure to static magnetic fields, radio-frequency fields, and time varying magnetic field gradients, focusing primarily on the physics of the interactions between these electromagnetic fields and biological matter. The scientific literature is summarized, integrated, and critically analyzed with the help of authoritative reviews by recognized experts, international safety guidelines are also cited.

  12. Simulation of Magnetic Resonance for Wireless Power Transfer

    Directory of Open Access Journals (Sweden)

    Liang Zhao

    2013-02-01

    Full Text Available André Kurs et al. et al. (2007 in Science 317, 83 titled Wireless Power Transfer via Strongly Coupled Magnetic Resonances, proposed a feasible scheme to near-field transfer electric energy. Here in this report we take note of our simulation on COMSOL 4.1.085 to repeat his counterpart in Chapter 4 of his master thesis. Due to huge requirement on memory size, my simulation fails to align with Kurs', but basic steps and setup instructions are given. Very importantly, every scholar with electromagnetic background would simply take this as magnetic inducing current in closed loops, exactly as we did. Yet, this imparts more essence on resonance. A look into coupled-mode theory will find this takes advantage of near-field magnetic field to transfer energy. A transformer, a true product of magnetic induction, if simply detached by a distance would greatly reduce its transfer efficiency, whereas magnetic resonance DOES NOT! So this is more than only magnetic induction. Although coupled-mode theory is still not physical enough to illustrate readers, neither does magnetic induction in Maxwell's equations give its simple picture! Coupled-mode theory perhaps is a simple way out quantitatively and mathematically.

  13. Malformations of cortical development:3T magnetic resonance imaging features

    Institute of Scientific and Technical Information of China (English)

    Bilal; Battal; Selami; Ince; Veysel; Akgun; Murat; Kocaoglu; Emrah; Ozcan; Mustafa; Tasar

    2015-01-01

    Malformation of cortical development(MCD) is a term representing an inhomogeneous group of central nervous system abnormalities, referring particularly to embriyological aspect as a consequence of any of the three developmental stages, i.e., cell proliferation, cell migration and cortical organization. These include cotical dysgenesis, microcephaly, polymicrogyria, schizencephaly, lissencephaly, hemimegalencephaly, heterotopia and focal cortical dysplasia. Since magnetic resonance imaging is the modality of choice that best identifies the structural anomalies of the brain cortex, we aimed to provide a mini review of MCD by using 3T magnetic resonance scanner images.

  14. Malformations of cortical development: 3T magnetic resonance imaging features

    Science.gov (United States)

    Battal, Bilal; Ince, Selami; Akgun, Veysel; Kocaoglu, Murat; Ozcan, Emrah; Tasar, Mustafa

    2015-01-01

    Malformation of cortical development (MCD) is a term representing an inhomogeneous group of central nervous system abnormalities, referring particularly to embriyological aspect as a consequence of any of the three developmental stages, i.e., cell proliferation, cell migration and cortical organization. These include cotical dysgenesis, microcephaly, polymicrogyria, schizencephaly, lissencephaly, hemimegalencephaly, heterotopia and focal cortical dysplasia. Since magnetic resonance imaging is the modality of choice that best identifies the structural anomalies of the brain cortex, we aimed to provide a mini review of MCD by using 3T magnetic resonance scanner images. PMID:26516429

  15. Magnetic Field Dependence and Q of the Josephson Plasma Resonance

    DEFF Research Database (Denmark)

    Pedersen, Niels Falsig; Finnegan, T. F.; Langenberg, D. N.

    1972-01-01

    The results of an experimental study of the magnetic field dependence of the Josephson-plasma-resonance frequency and linewidth in Pb-Pb oxide-Pb tunnel junctions are reported. In the presence of an external magnetic field, the plasma mode is found to be sensitive to an antisymmetric component...... of supercurrent density which is not observed in conventional measurements of the field-dependent critical current. The frequency and field dependence of the plasma-resonance linewidth are interpreted as evidence that the previously unobserved quasiparticle-pair-interference tunnel current predicted by Josephson...

  16. Computation of flow pressure fields from magnetic resonance velocity mapping.

    Science.gov (United States)

    Yang, G Z; Kilner, P J; Wood, N B; Underwood, S R; Firmin, D N

    1996-10-01

    Magnetic resonance phase velocity mapping has unrivalled capacities for acquiring in vivo multi-directional blood flow information. In this study, the authors set out to derive both spatial and temporal components of acceleration, and hence differences of pressure in a flow field using cine magnetic resonance velocity data. An efficient numerical algorithm based on the Navier-Stokes equations for incompressible Newtonian fluid was used. The computational approach was validated with in vitro flow phantoms. This work aims to contribute to a better understanding of cardiovascular dynamics and to serve as a basis for investigating pulsatile pressure/flow relationships associated with normal and impaired cardiovascular function. PMID:8892202

  17. Liver magnetic resonance imaging: State of the art

    Institute of Scientific and Technical Information of China (English)

    Paul; E; Sijens

    2010-01-01

    Magnetic resonance imaging (MRI) has now been used for about three decades to characterize the human liver in a non-invasive way, that is without the need of using ionizing radiation or removing tissue samples. During the past few years, technical progress has been considerable and novel applications of MRI have been implemented in the clinic. The beginning of a new decade offers an excellent opportunity for having fi ve experts to present their view on the current status of MRI (and magnetic resonance spec...

  18. Sodium Magnetic Resonance Imaging at 9.4 Tesla

    OpenAIRE

    Mirkes, Christian Carlo

    2014-01-01

    The motivation to perform magnetic resonance imaging (MRI) at ultra-high field strength (UHF) (B0 ≥ 7 Tesla) is primarily driven by the increased sensitivity compared to low field MRI. This is especially true for nuclei which exhibit intrinsically a low signal-to-noise ratio (SNR) either due to their physical properties or their small in vivo concentrations. The aim of this thesis was to establish the measurement techniques required for sodium magnetic resonance imaging at 9.4 Tesla and to ov...

  19. Magnetic resonance imaging as a tool for extravehicular activity analysis

    Science.gov (United States)

    Dickenson, R.; Lorenz, C.; Peterson, S.; Strauss, A.; Main, J.

    1992-01-01

    The purpose of this research is to examine the value of magnetic resonance imaging (MRI) as a means of conducting kinematic studies of the hand for the purpose of EVA capability enhancement. After imaging the subject hand using a magnetic resonance scanner, the resulting 2D slices were reconstructed into a 3D model of the proximal phalanx of the left hand. Using the coordinates of several landmark positions, one is then able to decompose the motion of the rigid body. MRI offers highly accurate measurements due to its tomographic nature without the problems associated with other imaging modalities for in vivo studies.

  20. Magnetic resonance imaging using gadolinium-based contrast agents.

    Science.gov (United States)

    Mitsumori, Lee M; Bhargava, Puneet; Essig, Marco; Maki, Jeffrey H

    2014-02-01

    The purpose of this article was to review the basic properties of available gadolinium-based magnetic resonance contrast agents, discuss their fundamental differences, and explore common and evolving applications of gadolinium-based magnetic resonance contrast throughout the body excluding the central nervous system. A more specific aim of this article was to explore novel uses of these gadolinium-based contrast agents and applications where a particular agent has been demonstrated to behave differently or be better suited for certain applications than the other contrast agents in this class.

  1. Magnetic Resonance Spectroscopy of siRNA-Based Cancer Therapy

    Science.gov (United States)

    Penet, Marie-France; Chen, Zhihang; Mori, Noriko; Krishnamachary, Balaji; Bhujwalla, Zaver M.

    2016-01-01

    Small interfering RNA (siRNA) is routinely used as a biological tool to silence specific genes, and is under active investigation in cancer treatment strategies. Noninvasive magnetic resonance spectroscopy (MRS) provides the ability to assess the functional effects of siRNA-mediated gene silencing in cultured cancer cells, and following nanoparticle-based delivery in tumors in vivo. Here we describe the use of siRNA to downregulate choline kinase, a critical enzyme in choline phospholipid metabolism of cancer cells and tumors, and the use of 1H MRS of cells and 1H magnetic resonance spectroscopic imaging (MRSI) of tumors to assess the efficacy of the downregulation. PMID:26530913

  2. Artifacts and pitfalls in shoulder magnetic resonance imaging.

    Science.gov (United States)

    Marcon, Gustavo Felix; Macedo, Tulio Augusto Alves

    2015-01-01

    Magnetic resonance imaging has revolutionized the diagnosis of shoulder lesions, in many cases becoming the method of choice. However, anatomical variations, artifacts and the particularity of the method may be a source of pitfalls, especially for less experienced radiologists. In order to avoid false-positive and false-negative results, the authors carried out a compilation of imaging findings that may simulate injury. It is the authors' intention to provide a useful, consistent and comprehensive reference for both beginner residents and skilled radiologists who work with musculoskeletal magnetic resonance imaging, allowing for them to develop more precise reports and helping them to avoid making mistakes.

  3. Noise Reduction in Magnetic Resonance Images using Wave Atom Shrinkage

    Directory of Open Access Journals (Sweden)

    J.Rajeesh, R.S.Moni, S.Palanikumar, T.Gopalakrishnan

    2010-06-01

    Full Text Available De-noising is always a challenging problem in magnetic resonance imaging andimportant for clinical diagnosis and computerized analysis, such as tissueclassification and segmentation. It is well known that the noise in magneticresonance imaging has a Rician distribution. Unlike additive Gaussian noise,Rician noise is signal dependent, and separating signal from noise is a difficulttask. An efficient method for enhancement of noisy magnetic resonance imageusing wave atom shrinkage is proposed. The reconstructed MRI data have highSignal to Noise Ratio (SNR compared to the curvelet and wavelet domain denoisingapproaches.

  4. Magnetic resonance tomography of the feet and ankles

    Energy Technology Data Exchange (ETDEWEB)

    Oesterreich, F.U.; Heller, M.; Maas, R.; Langkowski, J.H.; Hemker, T.

    1988-02-01

    21 patients with suspected, or known, abnormalities of the feet or ankles were examined by magnetic resonance tomography. The indications were: Osteochondritis dissecans of the talus (three cases), osteomyelitis (three cases), suspected tumour recurrence (three cases), undiagnosed pain (six cases) and a further miscellaneous six cases. Although most of these problems could have been solved with other imaging methods, magnetic resonance tomography did add some valuable diagnostic information. Because of its ability to demonstrate bones, synovia, tendons, vessels and subcutaneous fascia in a multi-directional manner, it is superior to all other imaging methods. It saves time by making it unnecessary to use a variety of diagnostic procedures.

  5. Magnetization transfer using inversion recovery during off-resonance irradiation.

    Science.gov (United States)

    Mangia, Silvia; De Martino, Federico; Liimatainen, Timo; Garwood, Michael; Michaeli, Shalom

    2011-12-01

    Estimation of magnetization transfer (MT) parameters in vivo can be compromised by an inability to drive the magnetization to a steady state using allowable levels of radiofrequency (RF) irradiation, due to safety concerns (tissue heating and specific absorption rate (SAR)). Rather than increasing the RF duration or amplitude, here we propose to circumvent the SAR limitation by sampling the formation of the steady state in separate measurements made with the magnetization initially along the -z and +z axis of the laboratory frame, i.e. with or without an on-resonance inversion pulse prior to the off-resonance irradiation. Results from human brain imaging demonstrate that this choice provides a tremendous benefit in the fitting procedure used to estimate MT parameters. The resulting parametric maps are characterized by notably increased tissue specificity as compared to those obtained with the standard MT acquisition in which magnetization is initially along the +z axis only. PMID:21601405

  6. Biomedical Investigations with Laser-Polarized Noble Gas Magnetic Resonance

    Science.gov (United States)

    Walsworth, Ronald L.

    2003-01-01

    We pursued advanced technology development of laser-polarized noble gas nuclear magnetic resonance (NMR) as a novel biomedical imaging tool for ground-based and eventually space-based application. This new multidisciplinary technology enables high-resolution gas-space magnetic resonance imaging (MRI)-e.g., of lung ventilation-as well as studies of tissue perfusion. In addition, laser-polarized noble gases (3He and 129Xe) do not require a large magnetic field for sensitive detection, opening the door to practical MRI at very low magnetic fields with an open, lightweight, and low-power device. We pursued two technology development specific aims: (1) development of low-field (less than 0.01 T) noble gas MRI of humans; and (2) development of functional MRI of the lung using laser-polarized noble gas and related techniques.

  7. Interaction between magnetic agglomerates and an extended free radicals network studied by magnetic resonance

    Science.gov (United States)

    Guskos, Niko; Zolnierkiewicz, Grzegorz; Typek, Janusz; Guskos, Aleksander; Berczynski, Pawel; Petridis, Dimitri

    2012-02-01

    Solids containing an extended network of free radicals have been prepared and studied by magnetic resonance techniques in the 4-290 K temperature range. One solid contained additionally a small amount of magnetic γ-Fe2O3 in the form of nanoparticle agglomerates. The solid without agglomerates displayed only a narrow, single resonance line centered at g eff = 2.0043. The magnetic resonance measurements of the solid with γ-Fe2O3 agglomerates gave a spectrum composed of two lines attributed to two different magnetic centers: a narrow line due to free radicals and a broad line arising from magnetic iron oxide agglomerates. In the high temperature range the integrated intensities of both lines decreased with decreasing temperature. The resonance field of the broad line shifted to lower magnetic fields upon lowering the temperature with the gradient ΔH r/ΔT = 2.3 G/K, while the narrow line shifted towards higher magnetic fields. The linewidth of the broader line increased with decreasing temperature while for the narrow lines in both samples this change was small. The magnetic iron oxide clusters produce a magnetic field which acts on the free radicals network and its strength depends essentially on the concentration of clusters. The reorientation process in the free radicals network is more intense in the sample without magnetic clusters.

  8. Utility of magnetic resonance spectroscopic imaging for human epilepsy

    OpenAIRE

    Pan, Jullie W; Kuzniecky, Ruben I.

    2015-01-01

    This review discusses the potential utility of broad based use of magnetic resonance (MR) spectroscopic imaging for human epilepsy and seizure localization. The clinical challenges are well known to the epilepsy community, intrinsic in the variability of location, volumetric size and network extent of epileptogenic tissue in individual patients. The technical challenges are also evident, with high performance requirements in multiple steps, including magnet homogeneity, detector performance, ...

  9. Magnetic resonance angiography: current status and future directions

    OpenAIRE

    François Christopher J; Grist Thomas M; Hartung Michael P

    2011-01-01

    Abstract With recent improvement in hardware and software techniques, magnetic resonance angiography (MRA) has undergone significant changes in technique and approach. The advent of 3.0 T magnets has allowed reduction in exogenous contrast dose without compromising overall image quality. The use of novel intravascular contrast agents substantially increases the image windows and decreases contrast dose. Additionally, the lower risk and cost in non-contrast enhanced (NCE) MRA has sparked renew...

  10. Resonant tunnel magnetoresistance in a double magnetic tunnel junction

    KAUST Repository

    Useinov, Arthur

    2011-08-09

    We present quasi-classical approach to calculate a spin-dependent current and tunnel magnetoresistance (TMR) in double magnetic tunnel junctions (DMTJ) FML/I/FMW/I/FMR, where the magnetization of the middle ferromagnetic metal layer FMW can be aligned parallel or antiparallel with respect to the fixed magnetizations of the left FML and right FMR ferromagnetic electrodes. The transmission coefficients for components of the spin-dependent current, and TMR are calculated as a function of the applied voltage. As a result, we found a high resonant TMR. Thus, DMTJ can serve as highly effective magnetic nanosensor for biological applications, or as magnetic memory cells by switching the magnetization of the inner ferromagnetic layer FMW.© Springer Science+Business Media, LLC 2011.

  11. One-pot synthesis of magnetic nanoclusters enabling atherosclerosis-targeted magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Kukreja A

    2014-05-01

    Full Text Available Aastha Kukreja,1 Eun-Kyung Lim,2–4 Byunghoon Kang,1 Yuna Choi,2 Taeksu Lee,1 Jin-Suck Suh,2,3 Yong-Min Huh,2,3 Seungjoo Haam1,31Department of Chemical and Biomolecular Engineering, College of Engineering, 2Department of Radiology, College of Medicine, Yonsei University, Seoul, Republic of Korea; 3YUHS-KRIBB Medical Convergence Research Institute, Seoul, Republic of Korea; 4BioNanotechnology Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of KoreaAbstract: In this study, dextran-encrusted magnetic nanoclusters (DMNCs were synthesized using a one-pot solution phase method for detection of atherosclerosis by magnetic resonance imaging. Pyrenyl dextran was used as a surfactant because of its electron-stabilizing effect and its amphiphilic nature, rendering the DMNCs stable and water-dispersible. The DMNCs were 65.6±4.3 nm, had a narrow size distribution, and were superparamagnetic with a high magnetization value of 60.1 emu/g. Further, they showed biocompatibility and high cellular uptake efficiency, as indicated by a strong interaction between dextran and macrophages. In vivo magnetic resonance imaging demonstrated the ability of DMNCs to act as an efficient magnetic resonance imaging contrast agent capable of targeted detection of atherosclerosis. In view of these findings, it is concluded that DMNCs can be used as magnetic resonance imaging contrast agents to detect inflammatory disease.Keywords: magnetic nanocrystal, magnetic resonance imaging, atherosclerosis, macrophages, dextran

  12. Complications after liver transplantation: evaluation with magnetic resonance imaging, magnetic resonance cholangiography, and 3-dimensional contrast-enhanced magnetic resonance angiography in a single session

    International Nuclear Information System (INIS)

    To evaluate a comprehensive magnetic resonance imaging (MRI) protocol as noninvasive diagnostic modality for simultaneous detection of parenchymal, biliary, and vascular complications after liver transplantation. Fifty-two liver transplant recipients suspected to have parenchymal, biliary, and (or) vascular complications underwent our MRI protocol at 1.5T unit using a phased array coil. After preliminary acquisition of axial T1w and T2w sequences, magnetic resonance cholangiography (MRC) was performed through a breath-hold, thin- and thick-slab, single-shot T2w sequence in the coronal plane. Contrast-enhanced magnetic resonance angiography (CEMRA) was obtained using a 3-dimensional coronal spoiled gradient-echo sequence, which enabled acquisition of 32 partitions 2.0 mm thick. A fixed dose of 20 ml gadobenate dimeglumine was administered at 2 mL/s. A post-contrast T1w sequence was also performed. Two observers in conference reviewed source images and 3-dimensional reconstructions to determine the presence of parenchymal, biliary, and vascular complications. MRI findings were correlated with surgery, endoscopic retrograde cholangiography (ERC), biopsy, digital subtraction angiography (DSA), and imaging follow-up. MRI revealed abnormal findings in 32 out of 52 patients (61%), including biliary complications (anastomotic and nonanastomotic strictures, and lithiasis) in 31, vascular disease (hepatic artery stenosis and thrombosis) in 9, and evidence of hepatic abscess and hematoma in 2. ERC confirmed findings of MRC in 30 cases, but suggested disease underestimation in 2. DSA confirmed 7 magnetic resonance angiogram (MRA) findings, but suggested disease overestimation in 2. MRI combined with MRC and CEMRA can provide a comprehensive assessment of parenchymal, biliary, and vascular complications in most recipients of liver transplantation. (author)

  13. Complications after liver transplantation: evaluation with magnetic resonance imaging, magnetic resonance cholangiography, and 3-dimensional contrast-enhanced magnetic resonance angiography in a single session

    Energy Technology Data Exchange (ETDEWEB)

    Boraschi, P.; Donati, F.; Gigoni, R. [Pisa Univ. Hospital, Second Dept. of Radiology, Pisa (Italy)], E-mail: p.boraschi@do.med.unipi.it; Salemi, S. [Univ. of Pisa, Diagnostic and Interventional Radiology, Pisa (Italy); Urbani, L.; Filipponi, F. [Univ. of Pisa, Liver Transplant Unit of the Dept. of Oncology, Transplants and Advanced Technologies in Medicine, Pisa (Italy); Falaschi, F. [Pisa Univ. Hospital, Second Dept. of Radiology, Pisa (Italy); Bartolozzi, C. [Univ. of Pisa, Diagnostic and Interventional Radiology, Pisa (Italy)

    2008-12-15

    To evaluate a comprehensive magnetic resonance imaging (MRI) protocol as noninvasive diagnostic modality for simultaneous detection of parenchymal, biliary, and vascular complications after liver transplantation. Fifty-two liver transplant recipients suspected to have parenchymal, biliary, and (or) vascular complications underwent our MRI protocol at 1.5T unit using a phased array coil. After preliminary acquisition of axial T{sub 1}w and T{sub 2}w sequences, magnetic resonance cholangiography (MRC) was performed through a breath-hold, thin- and thick-slab, single-shot T{sub 2}w sequence in the coronal plane. Contrast-enhanced magnetic resonance angiography (CEMRA) was obtained using a 3-dimensional coronal spoiled gradient-echo sequence, which enabled acquisition of 32 partitions 2.0 mm thick. A fixed dose of 20 ml gadobenate dimeglumine was administered at 2 mL/s. A post-contrast T{sub 1}w sequence was also performed. Two observers in conference reviewed source images and 3-dimensional reconstructions to determine the presence of parenchymal, biliary, and vascular complications. MRI findings were correlated with surgery, endoscopic retrograde cholangiography (ERC), biopsy, digital subtraction angiography (DSA), and imaging follow-up. MRI revealed abnormal findings in 32 out of 52 patients (61%), including biliary complications (anastomotic and nonanastomotic strictures, and lithiasis) in 31, vascular disease (hepatic artery stenosis and thrombosis) in 9, and evidence of hepatic abscess and hematoma in 2. ERC confirmed findings of MRC in 30 cases, but suggested disease underestimation in 2. DSA confirmed 7 magnetic resonance angiogram (MRA) findings, but suggested disease overestimation in 2. MRI combined with MRC and CEMRA can provide a comprehensive assessment of parenchymal, biliary, and vascular complications in most recipients of liver transplantation. (author)

  14. Magnetic resonance imaging without field cycling at less than earth's magnetic field

    Science.gov (United States)

    Lee, Seong-Joo; Shim, Jeong Hyun; Kim, Kiwoong; Yu, Kwon Kyu; Hwang, Seong-min

    2015-03-01

    A strong pre-polarization field, usually tenths of a milli-tesla in magnitude, is used to increase the signal-to-noise ratio in ordinary superconducting quantum interference device-based nuclear magnetic resonance/magnetic resonance imaging experiments. Here, we introduce an experimental approach using two techniques to remove the need for the pre-polarization field. A dynamic nuclear polarization (DNP) technique enables us to measure an enhanced resonance signal. In combination with a π / 2 pulse to avoid the Bloch-Siegert effect in a micro-tesla field, we obtained an enhanced magnetic resonance image by using DNP technique with a 34.5 μT static external magnetic field without field cycling. In this approach, the problems of eddy current and flux trapping in the superconducting pickup coil, both due to the strong pre-polarization field, become negligible.

  15. Magnetic resonance imaging without field cycling at less than earth's magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seong-Joo, E-mail: sj.lee@kriss.re.kr; Shim, Jeong Hyun; Kim, Kiwoong; Yu, Kwon Kyu; Hwang, Seong-min [Center for Biosignals, Korea Research Institute of Standards and Science (KRISS), 267 Gajeong-ro, Yuseong-gu, Daejeon 305-340 (Korea, Republic of)

    2015-03-09

    A strong pre-polarization field, usually tenths of a milli-tesla in magnitude, is used to increase the signal-to-noise ratio in ordinary superconducting quantum interference device-based nuclear magnetic resonance/magnetic resonance imaging experiments. Here, we introduce an experimental approach using two techniques to remove the need for the pre-polarization field. A dynamic nuclear polarization (DNP) technique enables us to measure an enhanced resonance signal. In combination with a π/2 pulse to avoid the Bloch-Siegert effect in a micro-tesla field, we obtained an enhanced magnetic resonance image by using DNP technique with a 34.5 μT static external magnetic field without field cycling. In this approach, the problems of eddy current and flux trapping in the superconducting pickup coil, both due to the strong pre-polarization field, become negligible.

  16. Electrically detected magnetic resonance of semiconductors and semiconductor devices

    International Nuclear Information System (INIS)

    Full text: Electrically detected magnetic resonance (EDMR) is a novel way of detecting resonant changes in the magnetoresistance of semiconductors. In most cases that have been studied to date, the resonant change is due to a change in the spin polarisation of recombination centres due to the resonant absorption of microwave radiation in a scanned magnetic field. In that case, EDMR is similar to electron spin resonance (ESR). EDMR is more sensitive than ESR and also it is specific to electrically active paramagnetic centres. In an entirely different form of EDMR, we have observed small, but well-resolved, features in the magnetoresistance of several semiconductors in the absence of microwave radiation. An explanation of some of these feature is provided in terms of a change in the spin polarisation due to a crossing of the Zeeman-split sub-levels of a recombination centre in the scanned magnetic field. The crossing of Zeeman sub-levels has been observed in optically detected magnetic resonance (ODMR) before. In other cases this explanation is not applicable and other possibilities must be considered. The features of a similar, but not the same, type have been observed so far from several devices: silicon Schottky diodes, InGaAs high electron mobility transistors (HEMT's) and most recently from tunnel diodes. The most notable properties of the features are that they are observable at room temperature and depend very sensitively on the orientation of the magnetic field B: the features move progressively over a range from 0.05 T to more than 1 T with angle. The experimental results will be presented and discussed in terms of theoretical models

  17. Magnetic resonance and structural study of the cluster fluoride Nb6F15

    International Nuclear Information System (INIS)

    In this work, we report updated structural data, obtained by single-crystal X-ray diffraction, on the binary fluoride Nb6F15 as well as measurements of 19F NMR over the temperature range 100-300K, and EMR measurements over the temperature range 4-300K. Nb6F15 is built up from Nb6F12iF6a octahedral cluster units sharing all apical fluorine ligands to form linear Nb-Fa-Nb interunit bridges (Fi: inner fluorine located in edge-bridging position, Fa: apical fluorine located in terminal position). The 19F NMR results showed two resonance lines. One line corresponds to the inner fluorine Fi in the (Nb6F12)-3 cluster core. The second 19F NMR line corresponds to the apical Fa. The shift of the NMR signal from Fi depends on the temperature and exhibits a Curie type behavior, while the position of the NMR signal from Fa is temperature independent. EMR measurements show a single Lorentzian line. The temperature dependence of the inverse of the intensity of the EMR line shows a Curie-Weiss behavior and an onset to an antiferromagnetic (AF) order at 5K. c (AF) order at 5K

  18. Development and optimization of resonators and ways of detection in nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Aims of this dissertation were to construct resonators for very high flux densities and to develop appropriate probe bases. These were successfully realized with numerous resonators as well as two kinds of probe bases. Furthermore, new techniques and methods of signal detection were developed and evaluated. Magnetic flux guides, which were unknown in NMR up until now were used for the first time for both transmission and reception. Moreover, an optical acquisition technique based on the Faraday effect was realized and evaluated

  19. The thermonuclear production of 19F by Wolf-Rayet stars revisited

    Science.gov (United States)

    Palacios, A.; Arnould, M.; Meynet, G.

    2005-11-01

    New models of rotating and non-rotating stars are computed for initial masses between 25 and 120 M_⊙ and for metallicities Z = 0.004, 0.008, 0.020, and 0.040 with the aim of reexamining the wind contribution of Wolf-Rayet (WR) stars to the 19F enrichment of the interstellar medium. Models with an initial rotation velocity υi = 300 km s-1 are found to globally eject less 19F than the non-rotating models. We compare our new predictions with those of Meynet & Arnould (2000, A&A, 355, 176), and demonstrate that the 19F yields are very sensitive to the still uncertain 19F (α ,p) 22Ne rate and to the adopted mass loss rates. Using the recommended mass loss rate values that take into account the clumping of the WR wind and the NACRE reaction rates, when available, we obtain WR 19F yields that are significantly lower than predicted by Meynet & Arnould (2000, A&A, 355, 176) and that would make WR stars non-important contributors to the galactic 19F budget. In view, however, of the large nuclear and mass loss rate uncertainties, we consider that the question of the WR contribution to the galactic 19F remains quite open.

  20. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... it’s commonly known, MRA. MRA is a noninvasive test that uses a powerful magnetic field and a computer to produce detailed pictures of the major blood vessels throughout your body. It may be performed with or without contrast material which, if needed, will be injected into a ...

  1. Safety recommendations in magnetic resonance imaging (MRI)

    International Nuclear Information System (INIS)

    Full text: In order to discuss the long-term biological effects of MRI in the radiological department, all the components of the acquisition process must be considered. Those elements include: the main magnetic field, time varying magnetic fields and radio-frequency fields (RF). Also must be referred other types of hazards obtained by the utilization of contrast materials as gadolinium or pregnancy. The primary concern with the static magnetic field is the possibility of potential biological effects. The majority of studies show no effects on cell growth and morphology at field strengths below 2T. Data accumulated by the National Institute for Occupational Safety, the World Health Organization, and the US State Department, show no evidence of leukemia or other carcinogenesis. The secondary concern of the effects of the main magnetic field is the hazards associated with the sitting of MR systems. The static magnetic field has no respect for the confines of conventional walls, floors or ceilings. Some reversible effects have been noted on Electrocardiogram gating (ECG) at these field strengths. An increase in the amplitude of the T-wave can be noted on an ECG due to the magnetohydrodynamic effect. This is produced when a conductive fluid, such as blood, moves across a magnetic field. Some reversible biological effects including fatigue, headaches, hypotension and accounts of irritability have been observed on human subjects exposed to 2T and above. As yet, there are no known biological effects of MRI on fetuses. Also MR facilities have established individual guidelines for pregnant employees in the MR environment. Ferromagnetic metal objects can become airborne as projectiles in the presence of a strong static magnetic field. Metallic implants pose serious effects which include torque, heating and artifacts on MR images.There have been a large number of studies performed on the biological effects from Time-varying magnetic field (TVMF), since they exist around power

  2. Observation of the uranium 235 nuclear magnetic resonance signal

    OpenAIRE

    Le Bail, H.; Chachaty, C.; Rigny, P.; Bougon, R.

    1983-01-01

    The first observation of the nuclear magnetic resonance of the uranium 235 is reported. It has been performed on pure liquid uranium hexafluoride at 380 K. The measured magnetogyric ratio is | γ(235U) | = 492.6 ± 0.2 rad.s-1 G-1.

  3. Magnetic Resonance Perfusion Imaging in the Study of Language

    Science.gov (United States)

    Hillis, Argye E.

    2007-01-01

    This paper provides a brief review of various uses of magnetic resonance perfusion imaging in the investigation of brain/language relationships. The reviewed studies illustrate how perfusion imaging can reveal areas of brain where dysfunction due to low blood flow is associated with specific language deficits, and where restoration of blood flow…

  4. Functional Connectivity Magnetic Resonance Imaging Classification of Autism

    Science.gov (United States)

    Anderson, Jeffrey S.; Nielsen, Jared A.; Froehlich, Alyson L.; DuBray, Molly B.; Druzgal, T. Jason; Cariello, Annahir N.; Cooperrider, Jason R.; Zielinski, Brandon A.; Ravichandran, Caitlin; Fletcher, P. Thomas; Alexander, Andrew L.; Bigler, Erin D.; Lange, Nicholas; Lainhart, Janet E.

    2011-01-01

    Group differences in resting state functional magnetic resonance imaging connectivity between individuals with autism and typically developing controls have been widely replicated for a small number of discrete brain regions, yet the whole-brain distribution of connectivity abnormalities in autism is not well characterized. It is also unclear…

  5. Myocardial wall motion imaging with cardiac magnetic resonance imaging

    NARCIS (Netherlands)

    Lubbers, Dani�l; Kuijpers, D.; Oudkerk, M.

    2006-01-01

    Wall motion imaging with cardiac magnetic resonance imaging (CMR) provides important functional information about global and regional myocardial function. This review will give an overview of the current state of myocardial wall motion imaging, especially focusing on the clinical role of dobutamine

  6. Advances in cardiac magnetic resonance imaging of congenital heart disease

    NARCIS (Netherlands)

    Driessen, Mieke M P; Breur, Johannes M. P. J.; Budde, Ricardo P J; van Oorschot, Joep W M; van Kimmenade, Roland R J; Sieswerda, Gertjan Tj.; Meijboom, Folkert J; Leiner, Tim

    2015-01-01

    Due to advances in cardiac surgery, survival of patients with congenital heart disease has increased considerably during the past decades. Many of these patients require repeated cardiovascular magnetic resonance imaging to assess cardiac anatomy and function. In the past decade, technological advan

  7. Magnetic resonance imaging in obstructive Müllerian anomalies

    OpenAIRE

    Kamal Kumar Sen; Dhivya Balasubramaniam; Vikrant Kanagaraj

    2013-01-01

    Herlyn-Werner-Wunderlich (HWW) syndrome is a very rare congenital anomaly of the urogenital tract involving Müllerian ducts and Wolffian structures. It is characterized by the triad of didelphys uterus, obstructed hemivagina, and ipsilateral renal agenesis. Magnetic resonance imaging (MRI) is a sensitive, non-invasive diagnostic modality for demonstrating anatomic variation and associated complications.

  8. Magnetic resonance imaging in obstructive Müllerian anomalies

    Directory of Open Access Journals (Sweden)

    Kamal Kumar Sen

    2013-01-01

    Full Text Available Herlyn-Werner-Wunderlich (HWW syndrome is a very rare congenital anomaly of the urogenital tract involving Müllerian ducts and Wolffian structures. It is characterized by the triad of didelphys uterus, obstructed hemivagina, and ipsilateral renal agenesis. Magnetic resonance imaging (MRI is a sensitive, non-invasive diagnostic modality for demonstrating anatomic variation and associated complications.

  9. Selection of planes in nuclear magnetic resonance tomography

    International Nuclear Information System (INIS)

    A prototype aiming to obtain images in nuclear magnetic resonance tomography was developed, by adjusting NMR spectrometer in the IFQSC Laboratory. The techniques for selecting planes were analysed by a set of computer codes, which were elaborated from Bloch equation solutions to simulate the spin system behaviour. Images were obtained using planes with thickness inferior to 1 cm. (M.C.K.)

  10. Magnetic resonance in hematological diseases. Imaging of bone marrow

    DEFF Research Database (Denmark)

    Jensen, K.E.

    1995-01-01

    Magnetic resonance imaging (MRI) is a highly sensitive alternative to plain radiography, CT, and radionuclide studies for the imaging of normal and abnormal bone marrow. The cellularity and the corresponding fat/water ratio within the bone marrow show clear changes in haematological diseases. Thi...

  11. [Magnetic resonance--personal experience with its use in otorhinolaryngology].

    Science.gov (United States)

    Skerík, P; Belán, A; Lízler, J; Dolejs, Z

    1989-07-01

    The authors present their initial experience with the visualization by magnetic resonance (MR) in otorhinolaryngology in the CSR. Due to multidimensional and high contrast visualization, MR facilitates greatly spatial orientation as regards localization and size of the pathological process. Its importance otorhinolaryngology is in particular in the diagnosis of neoplastic diseases. For some localizations of tumours MR is the method of choice. PMID:2791047

  12. Magnetic resonance imaging in the diagnostics of multiple sclerosis

    International Nuclear Information System (INIS)

    Multiple sclerosis is an important and frequent neurological disease and the diagnosis might be difficult. The clinical criteria of multiple sclerosis and the role of laboratory examinations in the diagnosis of the disease are discussed. In particular the help offered by the magnetic resonance imaging method is the subject of this paper. Three patients are reported and discussed

  13. Increased cerebral blood flow in preeclampsia with magnetic resonance imaging

    NARCIS (Netherlands)

    Zeeman, GG; Hatab, MR; Twickler, DM

    2004-01-01

    Objective: The purpose of this study was to compare third trimester and nonpregnant cerebral blood flow of women with preeclampsia to normotensive control subjects with the use of magnetic resonance imaging techniques. Study design: Nine normotensive pregnant women and 12 untreated women with preecl

  14. Magnetic resonance imaging in rheumatoid arthritis advances and research priorities

    DEFF Research Database (Denmark)

    Østergaard, Mikkel; McQueen, FM; Bird, P;

    2005-01-01

    Magnetic resonance imaging (MRI) has now been used extensively in cross-sectional and observational studies as well as in controlled clinical trials to assess disease activity and joint damage in rheumatoid arthritis (RA). MRI measurements or scores for erosions, bone edema, and synovitis have been...

  15. Whole-body magnetic resonance imaging: assessment of skeletal metastases.

    Science.gov (United States)

    Moynagh, Michael R; Colleran, Gabrielle C; Tavernaraki, Katarina; Eustace, Stephen J; Kavanagh, Eoin C

    2010-03-01

    The concept of a rapid whole-body imaging technique with high resolution and the absence of ionizing radiation for the assessment of osseous metastatic disease is a desirable tool. This review article outlines the current perspective of whole-body magnetic resonance imaging in the assessment of skeletal metastatic disease, with comparisons made to alternative whole-body imaging modalities.

  16. Does magnetic resonance imaging predict future low back pain?

    DEFF Research Database (Denmark)

    Steffens, D; Hancock, M J; Maher, C G;

    2014-01-01

    Magnetic resonance imaging (MRI) has the potential to identify pathology responsible for low back pain (LBP). However, the importance of findings on MRI remains controversial. We aimed to systematically review whether MRI findings of the lumbar spine predict future LBP in different samples with and...

  17. Magnetic resonance imaging of peripheral joints in rheumatic diseases

    DEFF Research Database (Denmark)

    Østergaard, Mikkel; Duer, Anne; Møller, Uffe;

    2004-01-01

    The need for better methods than the conventional clinical, biochemical and radiographical examinations in the management of inflammatory joint diseases is evident, since these methods are not sensitive or specific to early pathologies and subtle changes. Magnetic resonance imaging (MRI) offers...

  18. Three-Dimensional Magnetic Resonance Imaging of Velopharyngeal Structures

    Science.gov (United States)

    Bae, Youkyung; Kuehn, David P.; Sutton, Bradley P.; Conway, Charles A.; Perry, Jamie L.

    2011-01-01

    Purpose: To report the feasibility of using a 3-dimensional (3D) magnetic resonance imaging (MRI) protocol for examining velopharyngeal structures. Using collected 3D MRI data, the authors investigated the effect of sex on the midsagittal velopharyngeal structures and the levator veli palatini (levator) muscle configurations. Method: Ten Caucasian…

  19. Intraocular lymphoma after cardiac transplantation: Magnetic resonance imaging findings

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yi Kyung; Kim, Hyung Jin; Woo, Kyung In; Kim, Yoon Duck [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2013-01-15

    We report a case of intraocular lymphoma in a 65-year-old man, 15 months after cardiac transplantation. On Magnetic Resonance (MR) images, the iris and the anterior chamber of the right eye were found to be involved with an enhancing soft-tissue lesion. To our knowledge, this is the first case of post-transplantation intraocular lymphoma evaluated with MR imaging.

  20. RECONSTRUCTION OF HUMAN LUNG MORPHOLOGY MODELS FROM MAGNETIC RESONANCE IMAGES

    Science.gov (United States)

    Reconstruction of Human Lung Morphology Models from Magnetic Resonance ImagesT. B. Martonen (Experimental Toxicology Division, U.S. EPA, Research Triangle Park, NC 27709) and K. K. Isaacs (School of Public Health, University of North Carolina, Chapel Hill, NC 27514)

  1. Monitoring of aquifer pump tests with Magnetic Resonance Sounding (MRS)

    DEFF Research Database (Denmark)

    Herckenrath, Daan; Auken, Esben; Bauer-Gottwein, Peter

    2009-01-01

    Magnetic Resonance Sounding (MRS) can provide valuable data to constrain and calibrate groundwater flow and transport models. With this non-invasive geophysical technique, field measurements of water content and hydraulic conductivities can be obtained. We developed a hydrogeophyiscal forward met...

  2. C-13 nuclear magnetic resonance in organic geochemistry.

    Science.gov (United States)

    Balogh, B.; Wilson, D. M.; Burlingame, A. L.

    1972-01-01

    Study of C-13 nuclear magnetic resonance (NMR) spectra of polycyclic fused systems. The fingerprint qualities of the natural abundance in C-13 NMR spectra permitting unequivocal identification of these compounds is discussed. The principle of structural additivity of C-13 NMR information is exemplified on alpha and beta androstanes, alpha and beta cholestanes, ergostanes, sitostanes, and isodecanes.

  3. Using Nuclear Magnetic Resonance Spectroscopy for Measuring Ternary Phase Diagrams

    Science.gov (United States)

    Woodworth, Jennifer K.; Terrance, Jacob C.; Hoffmann, Markus M.

    2006-01-01

    A laboratory experiment is presented for the upper-level undergraduate physical chemistry curriculum in which the ternary phase diagram of water, 1-propanol and n-heptane is measured using proton nuclear magnetic resonance (NMR) spectroscopy. The experiment builds upon basic concepts of NMR spectral analysis, typically taught in the undergraduate…

  4. Nuclear Magnetic Resonance Coupling Constants and Electronic Structure in Molecules.

    Science.gov (United States)

    Venanzi, Thomas J.

    1982-01-01

    Theory of nuclear magnetic resonance spin-spin coupling constants and nature of the three types of coupling mechanisms contributing to the overall spin-spin coupling constant are reviewed, including carbon-carbon coupling (neither containing a lone pair of electrons) and carbon-nitrogen coupling (one containing a lone pair of electrons).…

  5. Magnetic resonance imaging, radiography, and scintigraphy of the finger joints

    DEFF Research Database (Denmark)

    Klarlund, M; Ostergaard, M; Jensen, K E;

    2000-01-01

    To evaluate synovial membrane hypertrophy, tenosynovitis, and erosion development of the 2nd to 5th metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints by magnetic resonance imaging in a group of patients with rheumatoid arthritis (RA) or suspected RA followed up for one year...

  6. Analysis and exploitation of field imperfections in magnetic resonance imaging

    NARCIS (Netherlands)

    Peeters, Johannes Martinus

    2006-01-01

    Field imperfections are normally undesirable in magnetic resonance imaging. They degrade the quality of the images by wrong depiction of the anatomy and decrease of the signal-to-noise ratio. Furthermore, for velocity, flow and diffusion quantification, measurement errors related to these imperfecti

  7. Magnetic resonance imaging of the breast: A clinicial perspective

    Directory of Open Access Journals (Sweden)

    Jenny Edge

    2012-06-01

    Full Text Available The role of magnetic resonance imaging (MRI in screening for breast cancer and its use after the diagnosis of breast cancer is discussed. The topic is enormous, with over 5 000 papers published in the last 10 years. In this précis, we focused on articles that examine its clinical relevance. We did not look at economic factors.

  8. Magnetic Resonance in trigeminal neuralgia: Presentation of three cases

    International Nuclear Information System (INIS)

    Trigeminal neuralgia is characterized by episodes of acute facial pain. lt can be caused by diverse pathologies that affect anyone of the segments of the V cranial nerve. Magnetic resonance is of choice when imaging studies are necessary. Three cases evaluated by this modality and confirmed by surgery are shown

  9. Yeast Lipid Estimation by Enzymatic and Nuclear Magnetic Resonance Methods

    OpenAIRE

    Moreton, R. S.

    1989-01-01

    Low-resolution nuclear magnetic resonance and enzymatic glycerol estimation were compared with a solvent extraction method for estimating the intracellular lipid content of lipid-accumulating yeasts. Both methods correlated well with the solvent extraction procedure and were more convenient with large numbers of samples.

  10. Ultrasound versus high field magnetic resonance imaging in rheumatoid arthritis

    DEFF Research Database (Denmark)

    Tan, York Kiat; Østergaard, Mikkel; Bird, Paul;

    2014-01-01

    Over the past decade there have been significant advances in the field of musculoskeletal imaging, especially in the application of ultrasound (US) and magnetic resonance imaging (MRI) to the management of rheumatoid arthritis (RA). Both modalities offer significant advantages over the previous...

  11. Magnetic Resonance Imaging in Follow-up Assessment of Sciatica

    NARCIS (Netherlands)

    el Barzouhi, Abdelilah; Vleggeert-Lankamp, Carmen L. A. M.; Nijeholt, Geert J. Lycklama A.; Van der Kallen, Bas F.; van den Hout, Wilbert B.; Jacobs, Wilco C. H.; Koes, Bart W.; Peul, Wilco C.

    2013-01-01

    BACKGROUND Magnetic resonance imaging (MRI) is frequently performed during follow-up in patients with known lumbar-disk herniation and persistent symptoms of sciatica. The association between findings on MRI and clinical outcome is controversial. METHODS We studied 283 patients in a randomized trial

  12. INVIVO PHOSPHORUS MAGNETIC-RESONANCE SPECTROSCOPY IN MULTIPLE-SCLEROSIS

    NARCIS (Netherlands)

    MINDERHOUD, JM; MOOYAART, EL; KAMMAN, RL; TEELKEN, AW; HOOGSTRATEN, MC; VENCKEN, LM; GRAVENMADE, EJ; VANDENBURG, W

    1992-01-01

    Localized phosphorus magnetic resonance spectroscopy at 1.5 T was performed in 39 patients with multiple sclerosis and in 15 healthy controls. The multiple sclerosis spectra showed increased creatine phosphate levels. This increase was correlated with the severity of the handicap and was greater in

  13. Radiofrequency solutions in clinical high field magnetic resonance

    NARCIS (Netherlands)

    Andreychenko, A.

    2013-01-01

    Magnetic resonance imaging (MRI) and spectroscopy (MRS) benefit from the sensitivity gain at high field (≥7T). However, high field brings also certain challenges associated with growing frequency and spectral dispersion. Frequency growth results in degraded performance of large volume radiofrequency

  14. Magnetic resonance imaging of bone tumours and mimics: pictorial essay

    International Nuclear Information System (INIS)

    Magnetic resonance imaging (MRI) plays several roles in the evaluation of bone tumours and tumour-like conditions. Basic MRI technique for evaluation of bone tumours is discussed in this article, and the local staging of bone tumours and the MRI appearance of common and characteristic osseous lesions are reviewed. (author)

  15. Magnetic Resonance Microscopy Spatially Resolved NMR Techniques and Applications

    CERN Document Server

    Codd, Sarah

    2008-01-01

    This handbook and ready reference covers materials science applications as well as microfluidic, biomedical and dental applications and the monitoring of physicochemical processes. It includes the latest in hardware, methodology and applications of spatially resolved magnetic resonance, such as portable imaging and single-sided spectroscopy. For materials scientists, spectroscopists, chemists, physicists, and medicinal chemists.

  16. The 20 year evolution of dobutamine stress cardiovascular magnetic resonance

    OpenAIRE

    Hundley W; Charoenpanichkit Charaslak

    2010-01-01

    Abstract Over the past 20 years, investigators world-wide have developed and utilized dobutamine magnetic resonance stress testing procedures for the purpose of identifying ischemia, viability, and cardiac prognosis. This article traces these developments and reviews the data utilized to substantiate this relatively new noninvasive imaging procedure.

  17. Cardiovascular magnetic resonance findings in a case of Danon disease

    OpenAIRE

    Kosieradzka Agnieszka; Walczak Ewa; Kuch Marek; Kownacki Lukasz; Piotrowska-Kownacka Dorota; Fidzianska Anna; Krolicki Leszek

    2009-01-01

    Abstract Danon disease is a rare X-linked dominant lysosomal glycogen storage disease that can lead to severe ventricular hypertrophy and heart failure. We report a case of Danon disease with cardiac involvement evaluated with cardiovascular magnetic resonance, including late gadolinium enhancement and perfusion studies.

  18. Magnetic resonance imaging in obstructive Müllerian anomalies.

    Science.gov (United States)

    Sen, Kamal Kumar; Balasubramaniam, Dhivya; Kanagaraj, Vikrant

    2013-04-01

    Herlyn-Werner-Wunderlich (HWW) syndrome is a very rare congenital anomaly of the urogenital tract involving Müllerian ducts and Wolffian structures. It is characterized by the triad of didelphys uterus, obstructed hemivagina, and ipsilateral renal agenesis. Magnetic resonance imaging (MRI) is a sensitive, non-invasive diagnostic modality for demonstrating anatomic variation and associated complications. PMID:24082660

  19. Magnetic resonance in superparamagnetic zinc ferrite

    Indian Academy of Sciences (India)

    Jitendra Pal Singh; Gagan Dixit; R C Srivastava; Hemant Kumar; H M Agrawal; Prem Chand

    2013-08-01

    In the present work, we have synthesized zinc ferrite nanoparticles by nitrate method. Presence of almost zero value of coercivity and remanence in the hysteresis of these samples shows the superparamagnetic nature at room temperature. Electron paramagnetic resonance spectroscopy performed on these samples in the temperature range 120–300 K indicates the systematic variation of the line-shapes of the spectra with temperature. Both gvalue and peak-to-peak linewidth decrease with increase in temperature. The variation of g-values and peak-topeak linewidth with temperature has been fitted with existing models and we observed different values of activation energies of the spins for both the samples.

  20. Resonances of the helium atom in a strong magnetic field

    DEFF Research Database (Denmark)

    Lühr, Armin Christian; Al-Hujaj, Omar-Alexander; Schmelcher, Peter

    2007-01-01

    We present an investigation of the resonances of a doubly excited helium atom in a strong magnetic field covering the regime B=0–100  a.u. A full-interaction approach which is based on an anisotropic Gaussian basis set of one-particle functions being nonlinearly optimized for each field strength...... is employed. Accurate results for a total of 17 resonances below the threshold consisting of He+ in the N=2 state are reported in this work. This includes states with total magnetic quantum numbers M=0,−1,−2 and even z parity. The corresponding binding energies are compared to approximate energies of two......-particle configurations consisting of two hydrogenlike electrons in the strong-field regime, thereby providing an understanding of the behavior of the energies of the resonances with varying field strength....