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Sample records for advanced magnetic resonance

  1. 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.

  2. 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.

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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.

  8. 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

  9. 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

  10. 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.

  11. 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

  12. 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...

  13. 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

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

    International Nuclear Information System (INIS)

    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.)

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

    Science.gov (United States)

    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 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. PMID:25552386

  16. 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.)

  17. 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.

  18. 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

  19. An atypical meningioma demystified and advanced magnetic resonance imaging techniques

    Directory of Open Access Journals (Sweden)

    Despoina Voultsinou

    2014-01-01

    Full Text Available A 40-year-old male presented with visuospatial processing disturbances. Family history was free. Conventional and advanced magnetic resonance imaging (MRI studies were performed. On T2 and fluid attenuation inversion recovery images, an increased signal intensity extra-axial lesion was demonstrated. Post-contrast scans depicted homogeneous intense contrast medium enhancement. T2FNx01 star sequence was negative for hemorrhagic or calcification foci. Diffusion-weighted imaging findings were indicative of malignant behavior and magnetic resonance venography confirmed superior sagittal sinus infiltration. Increased cerebral blood volume values were observed and peri-lesional oedema on perfusion-weighted imaging was also demonstrated. The signal intensity-time curve depicted the characteristic meningioma pattern. Spectroscopy showed increased choline and alanine levels, but decreased N-acetyl-aspartate levels. Conventional MRI is adequate for typical types of meningiomas. However, the more atypical ones, in which even the histopathologic specimen may demonstrate characteristics of typical meningioma, could be easier diagnosed with advanced MRI techniques.

  20. Advances in Magnetic Resonance Imaging Contrast Agents for Biomarker Detection

    Science.gov (United States)

    Sinharay, Sanhita; Pagel, Mark D.

    2016-06-01

    Recent advances in magnetic resonance imaging (MRI) contrast agents have provided new capabilities for biomarker detection through molecular imaging. MRI contrast agents based on the T2 exchange mechanism have more recently expanded the armamentarium of agents for molecular imaging. Compared with T1 and T2* agents, T2 exchange agents have a slower chemical exchange rate, which improves the ability to design these MRI contrast agents with greater specificity for detecting the intended biomarker. MRI contrast agents that are detected through chemical exchange saturation transfer (CEST) have even slower chemical exchange rates. Another emerging class of MRI contrast agents uses hyperpolarized 13C to detect the agent with outstanding sensitivity. These hyperpolarized 13C agents can be used to track metabolism and monitor characteristics of the tissue microenvironment. Together, these various MRI contrast agents provide excellent opportunities to develop molecular imaging for biomarker detection.

  1. 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...

  2. Parry-Romberg syndrome: findings in advanced magnetic resonance imaging sequences - case report

    International Nuclear Information System (INIS)

    Parry-Romberg syndrome is a rare disease characterized by progressive hemifacial atrophy associated with other systemic changes, including neurological symptoms. Currently, there are few studies exploring the utilization of advanced magnetic resonance sequences in the investigation of this disease. The authors report the case of a 45-year-old patient and describe the findings at structural magnetic resonance imaging and at advanced sequences, correlating them with pathophysiological data. (author)

  3. Parry-Romberg syndrome: findings in advanced magnetic resonance imaging sequences - case report

    Energy Technology Data Exchange (ETDEWEB)

    Paula, Rafael Alfenas de; Ribeiro, Bruno Niemeyer de Freitas, E-mail: alfenas85@gmail.com [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Hospital Universitario Clementino Fraga Filho; Bahia, Paulo Roberto Valle [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Dept. de radiologia; Ribeiro, Renato Niemeyer de Freitas [Hospital de Clinica de Jacarepagua, Rio de Janeiro, RJ (Brazil); Carvalho, Lais Balbi de [Universidade Presidente Antonio Carlos (Unipac), Juiz de Fora, MG (Brazil)

    2014-05-15

    Parry-Romberg syndrome is a rare disease characterized by progressive hemifacial atrophy associated with other systemic changes, including neurological symptoms. Currently, there are few studies exploring the utilization of advanced magnetic resonance sequences in the investigation of this disease. The authors report the case of a 45-year-old patient and describe the findings at structural magnetic resonance imaging and at advanced sequences, correlating them with pathophysiological data. (author)

  4. 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...... developed and validated by several groups. The OMERACT criteria require that outcome measures demonstrate adequate validity, discriminative power, and feasibility if they are to be useful in clinical trials. Specific performance targets for these criteria depend on the scientific, regulatory, logistical......, and financial context of the study in question. We review the extent to which MRI assessments of joint erosion, bone edema, and synovitis fulfil these criteria, particularly as they relate to proof-of-concept RA clinical trials....

  5. NATO Advanced Study Institute on Magnetic Resonance : Introduction, Advanced Topics and Applications to Fossil Energy

    CERN Document Server

    Fraissard, Jacques

    1984-01-01

    This volume contains the lectures presented at an Advanced Study Institute on "Magnetic Resonance Techniques in Fossil Energy Problems," which was held at the village of Maleme, Crete, in July of 1983. As of this writing, a different popular attitude prevails from that when the ASI was proposed as far as how critical the world energy picture is. In the popular press, a panglossian attitude (the "petroleum glut" of the 80's) has replaced the jeremiads of the 70's ( a catastrophic "energy crisis"). Yet, there are certain important constants: (a) for the foreseeable future, fossil energy sources (petroleum, coal, oil shale, etc. ) will continue to be of paramount importance; and (b) science and technology of the highest order are needed to extend the fossil ener~y resource base and to utilize it in a cost-effective manner that is also environmentally acceptable. It is precisely this second item that this volume addresses. The volume introduces the phenomenology of magnetic resonance ~n a unified and detailed man...

  6. Solid state nuclear magnetic resonance investigations of advanced energy materials

    Science.gov (United States)

    Bennett, George D.

    In order to better understand the physical electrochemical changes that take place in lithium ion batteries and asymmetric hybrid supercapacitors solid state nuclear magnetic resonance (NMR) spectroscopy has been useful to probe and identify changes on the atomic and molecular level. NMR is used to characterize the local environment and investigate the dynamical properties of materials used in electrochemical storage devices (ESD). NMR investigations was used to better understand the chemical composition of the solid electrolyte interphase which form on the negative and positive electrodes of lithium batteries as well as identify the breakdown products that occur in the operation of the asymmetric hybrid supercapacitors. The use of nano-structured particles in the development of new materials causes changes in the electrical, structural and other material properties. NMR was used to investigate the affects of fluorinated and non fluorinated single wall nanotubes (SWNT). In this thesis three experiments were performed using solid state NMR samples to better characterize them. The electrochemical reactions of a lithium ion battery determine its operational profile. Numerous means have been employed to enhance battery cycle life and operating temperature range. One primary means is the choice and makeup of the electrolyte. This study focuses on the characteristics of the solid electrolyte interphase (SEI) that is formed on the electrodes surface during the charge discharge cycle. The electrolyte in this study was altered with several additives in order to determine the influence of the additives on SEI formation as well as the intercalation and de-intercalation of lithium ions in the electrodes. 7Li NMR studies where used to characterize the SEI and its composition. Solid state NMR studies of the carbon enriched acetonitrile electrolyte in a nonaqueous asymmetric hybrid supercapacitor were performed. Magic angle spinning (MAS) coupled with cross polarization NMR

  7. Advanced techniques in magnetic resonance imaging of the brain in children with ADHD

    Energy Technology Data Exchange (ETDEWEB)

    Pastura, Giuseppe, E-mail: giuseppe.pastura@terra.com.b [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Instituto de Puericultura e Pediatria Martagao Gesteira. Dept. de Pediatria; Mattos, Paulo [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Instituto de Puericultura e Pediatria Martagao Gesteira. Dept. de Psiquiatria; Gasparetto, Emerson Leandro [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Instituto de Puericultura e Pediatria Martagao Gesteira. Dept. de Radiologia; Araujo, Alexandra Prufer de Queiroz Campos [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Instituto de Puericultura e Pediatria Martagao Gesteira. Dept. de Neuropediatria

    2011-04-15

    Attention deficit hyperactivity disorder (ADHD) affects about 5% of school-aged child. Previous published works using different techniques of magnetic resonance imaging (MRI) have demonstrated that there may be some differences between the brain of people with and without this condition. This review aims at providing neurologists, pediatricians and psychiatrists an update on the differences between the brain of children with and without ADHD using advanced techniques of magnetic resonance imaging such as diffusion tensor imaging, brain volumetry and cortical thickness, spectroscopy and functional MRI. Data was obtained by a comprehensive, non-systematic review of medical literature. The regions with a greater number of abnormalities are splenium of the corpus callosum, cingulated gyrus, caudate nucleus, cerebellum, striatum, frontal and temporal cortices. The brain regions where abnormalities are observed in studies of diffusion tensor, volumetry, spectroscopy and cortical thickness are the same involved in neurobiological theories of ADHD coming from studies with functional magnetic resonance imaging. (author)

  8. Advanced techniques in magnetic resonance imaging of the brain in children with ADHD

    International Nuclear Information System (INIS)

    Attention deficit hyperactivity disorder (ADHD) affects about 5% of school-aged child. Previous published works using different techniques of magnetic resonance imaging (MRI) have demonstrated that there may be some differences between the brain of people with and without this condition. This review aims at providing neurologists, pediatricians and psychiatrists an update on the differences between the brain of children with and without ADHD using advanced techniques of magnetic resonance imaging such as diffusion tensor imaging, brain volumetry and cortical thickness, spectroscopy and functional MRI. Data was obtained by a comprehensive, non-systematic review of medical literature. The regions with a greater number of abnormalities are splenium of the corpus callosum, cingulated gyrus, caudate nucleus, cerebellum, striatum, frontal and temporal cortices. The brain regions where abnormalities are observed in studies of diffusion tensor, volumetry, spectroscopy and cortical thickness are the same involved in neurobiological theories of ADHD coming from studies with functional magnetic resonance imaging. (author)

  9. Force-detected nuclear magnetic resonance: recent advances and future challenges

    International Nuclear Information System (INIS)

    We review recent efforts to detect small numbers of nuclear spins using magnetic resonance force microscopy. Magnetic resonance force microscopy (MRFM) is a scanning probe technique that relies on the mechanical measurement of the weak magnetic force between a microscopic magnet and the magnetic moments in a sample. Spurred by the recent progress in fabricating ultrasensitive force detectors, MRFM has rapidly improved its capability over the last decade. Today it boasts a spin sensitivity that surpasses conventional, inductive nuclear magnetic resonance detectors by about eight orders of magnitude. In this review we touch on the origins of this technique and focus on its recent application to nanoscale nuclear spin ensembles, in particular on the imaging of nanoscale objects with a three-dimensional (3D) spatial resolution better than 10 nm. We consider the experimental advances driving this work and highlight the underlying physical principles and limitations of the method. Finally, we discuss the challenges that must be met in order to advance the technique towards single nuclear spin sensitivity-and perhaps-to 3D microscopy of molecules with atomic resolution. (topical review)

  10. Recent Advances in Computational Methods for Nuclear Magnetic Resonance Data Processing

    KAUST Repository

    Gao, Xin

    2013-01-11

    Although three-dimensional protein structure determination using nuclear magnetic resonance (NMR) spectroscopy is a computationally costly and tedious process that would benefit from advanced computational techniques, it has not garnered much research attention from specialists in bioinformatics and computational biology. In this paper, we review recent advances in computational methods for NMR protein structure determination. We summarize the advantages of and bottlenecks in the existing methods and outline some open problems in the field. We also discuss current trends in NMR technology development and suggest directions for research on future computational methods for NMR.

  11. Development of advanced magnetic resonance sensor for industrial applications. Final report

    Energy Technology Data Exchange (ETDEWEB)

    De Los Santos, A.

    1997-06-01

    Southwest Research Institute (SwRI) and various subcontractors, in a cooperative agreement with the DOE, have developed and tested an advanced magnetic resonance (MR) sensor for several industrial applications and made various market surveys. The original goal of the program was to develop an advanced moisture sensor to allow more precise and rapid control of drying processes so that energy and/or product would not be wasted. Over the course of the program, it was shown that energy savings were achievable but in many processes the return in investment did not justify the cost of a magnetic resonance sensor. However, in many processes, particularly chemical, petrochemical, paper and others, the return in investment can be very high as to easily justify the cost of a magnetic resonance sensor. In these industries, substantial improvements in product yield, quality, and efficiency in production can cause substantial energy savings and reductions in product wastage with substantial environmental effects. The initial applications selected for this program included measurement of corn gluten at three different points and corn germ at one point in an American Maize corn processing plant. During the initial phases (I and II) of this program, SwRI developed a prototype advanced moisture sensor utilizing NMR technology capable of accurately and reliably measuring moisture in industrial applications and tested the sensor in the laboratory under conditions simulating on-line products in the corn wet milling industry. The objective of Phase III was to test the prototype sensor in the plant environment to determine robustness, reliability and long term stability. Meeting these objectives would permit extended field testing to improve the statistical database used to calibrate the sensor and subject the sensor to true variations in operating conditions encountered in the process rather than those which could only be simulated in the laboratory.

  12. Recent Advances in 19Fluorine Magnetic Resonance Imaging with Perfluorocarbon Emulsions

    Science.gov (United States)

    Schmieder, Anne H.; Caruthers, Shelton D.; Keupp, Jochen; Wickline, Samuel A.; Lanza, Gregory M.

    2016-01-01

    The research roots of 19fluorine (19F) magnetic resonance imaging (MRI) date back over 35 years. Over that time span, 1H imaging flourished and was adopted worldwide with an endless array of applications and imaging approaches, making magnetic resonance an indispensable pillar of biomedical diagnostic imaging. For many years during this timeframe, 19F imaging research continued at a slow pace as the various attributes of the technique were explored. However, over the last decade and particularly the last several years, the pace and clinical relevance of 19F imaging has exploded. In part, this is due to advances in MRI instrumentation, 19F/1H coil designs, and ultrafast pulse sequence development for both preclinical and clinical scanners. These achievements, coupled with interest in the molecular imaging of anatomy and physiology, and combined with a cadre of innovative agents, have brought the concept of 19F into early clinical evaluation. In this review, we attempt to provide a slice of this rich history of research and development, with a particular focus on liquid perfluorocarbon compound-based agents.

  13. 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 ...

  14. 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 . ...

  15. Use of Advanced Magnetic Resonance Imaging Techniques in Neuromyelitis Optica Spectrum Disorder

    DEFF Research Database (Denmark)

    Kremer, S.; Renard, F.; Achard, S.;

    2015-01-01

    Brain parenchymal lesions are frequently observed on conventional magnetic resonance imaging (MRI) scans of patients with neuromyelitis optica (NMO) spectrum disorder but the specific morphological and temporal patterns distinguishing them uneqtaivcally from lesions caused by other disorders have...

  16. Advanced echocardiography and cardiac magnetic resonance in congenital heart disease : insights in right ventricular mechanics and clinical implications

    NARCIS (Netherlands)

    Hulst, Anna Elisabeth van der

    2011-01-01

    The thesis provides new insights into advanced echocardiographic and magnetic resonance imaging techniques for comprehensive mechanical assessment of the right ventricle in healthy children and in pediatric patients with right ventricular dysfunction. It is shown that the right ventricle does not co

  17. Recent Advances in Characterization of Lignin Polymer by Solution-State Nuclear Magnetic Resonance (NMR Methodology

    Directory of Open Access Journals (Sweden)

    Run-Cang Sun

    2013-01-01

    Full Text Available The demand for efficient utilization of biomass induces a detailed analysis of the fundamental chemical structures of biomass, especially the complex structures of lignin polymers, which have long been recognized for their negative impact on biorefinery. Traditionally, it has been attempted to reveal the complicated and heterogeneous structure of lignin by a series of chemical analyses, such as thioacidolysis (TA, nitrobenzene oxidation (NBO, and derivatization followed by reductive cleavage (DFRC. Recent advances in nuclear magnetic resonance (NMR technology undoubtedly have made solution-state NMR become the most widely used technique in structural characterization of lignin due to its versatility in illustrating structural features and structural transformations of lignin polymers. As one of the most promising diagnostic tools, NMR provides unambiguous evidence for specific structures as well as quantitative structural information. The recent advances in two-dimensional solution-state NMR techniques for structural analysis of lignin in isolated and whole cell wall states (in situ, as well as their applications are reviewed.

  18. Locally Advanced Prostate Cancer: Three-Dimensional Magnetic Resonance Spectroscopy to Monitor Prostate Response to Therapy

    International Nuclear Information System (INIS)

    Purpose: To correlate results of three-dimensional magnetic resonance spectroscopic imaging (MRSI) with prostate-specific antigen (PSA) levels and time since external beam irradiation (EBRT) in patients treated with long-term hormone therapy (HT) and EBRT for locally advanced disease to verify successful treatment by documenting the achievement of metabolic atrophy (MA). Methods and Materials: Between 2006 and 2008, 109 patients were consecutively enrolled. MA was assessed by choline and citrate peak area-to-noise-ratio 1.5:1 or choline signal-to-noise-ratio >5:1. To test the strength of association between MRSI results and the time elapsed since EBRT (TEFRT), PSA levels, Gleason score (GS), and stage, logistic regression (LR) was performed. p value 2 years. MA was detected in 54.1% of patients of group 1, 88.9% of group 2, and in 94.5% of group 3 (100% when PSA nadir was reached). CM was detected in 50% of patients with reached PSA nadir in group 1. Local relapse was found in 3 patients previously showing CM at long TEFRT. Conclusion: MA detection, indicative of successful treatment because growth of normal or abnormal cells cannot occur without metabolism, increases with decreasing PSA levels and increasing time on HT after EBRT. This supports long-term HT in advanced prostate cancer. Larger study series are needed to assess whether MRSI could predict local relapse by detecting CM at long TEFRT.

  19. Advances and applications of dynamic-angle spinning nuclear magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Baltisberger, J.H.

    1993-06-01

    This dissertation describes nuclear magnetic resonance experiments and theory which have been developed to study quadrupolar nuclei (those nuclei with spin greater than one-half) in the solid state. Primarily, the technique of dynamic-angle spinning (DAS) is extensively reviewed and expanded upon in this thesis. Specifically, the improvement in both the resolution (two-dimensional pure-absorptive phase methods and DAS angle choice) and sensitivity (pulse-sequence development), along with effective spinning speed enhancement (again through choice of DAS conditions or alternative multiple pulse schemes) of dynamic-angle spinning experiment was realized with both theory and experimental examples. The application of DAS to new types of nuclei (specifically the {sup 87}Rb and {sup 85}Rb nuclear spins) and materials (specifically amorphous solids) has also greatly expanded the possibilities of the use of DAS to study a larger range of materials. This dissertation is meant to demonstrate both recent advances and applications of the DAS technique, and by no means represents a comprehensive study of any particular chemical problem.

  20. Advances and applications of dynamic-angle spinning nuclear magnetic resonance

    International Nuclear Information System (INIS)

    This dissertation describes nuclear magnetic resonance experiments and theory which have been developed to study quadrupolar nuclei (those nuclei with spin greater than one-half) in the solid state. Primarily, the technique of dynamic-angle spinning (DAS) is extensively reviewed and expanded upon in this thesis. Specifically, the improvement in both the resolution (two-dimensional pure-absorptive phase methods and DAS angle choice) and sensitivity (pulse-sequence development), along with effective spinning speed enhancement (again through choice of DAS conditions or alternative multiple pulse schemes) of dynamic-angle spinning experiment was realized with both theory and experimental examples. The application of DAS to new types of nuclei (specifically the 87Rb and 85Rb nuclear spins) and materials (specifically amorphous solids) has also greatly expanded the possibilities of the use of DAS to study a larger range of materials. This dissertation is meant to demonstrate both recent advances and applications of the DAS technique, and by no means represents a comprehensive study of any particular chemical problem

  1. Advancing Cardiovascular, Neurovascular and Renal Magnetic Resonance Imaging in Small Rodents Using Cryogenic Radiofrequency Coil Technology

    Directory of Open Access Journals (Sweden)

    Thoralf eNiendorf

    2015-11-01

    Full Text Available Research in pathologies of the brain, heart and kidney have gained immensely from the plethora of studies that have helped shape new methods in magnetic resonance (MR for characterizing preclinical disease models. Methodical probing into preclinical animal models by MR is invaluable since it allows a careful interpretation and extrapolation of data derived from these models to human disease. In this review we will focus on the applications of cryogenic radiofrequency (RF coils in small animal MR as a means of boosting image quality (e.g. by supporting MR microscopy and making data acquisition more efficient (e.g. by reducing measuring time; both being important constituents for thorough investigational studies on animal models of disease. This review attempts to make the (biomedical imaging, molecular medicine and pharmaceutical communities aware of this productive ferment and its outstanding significance for anatomical and functional MR in small rodents. The goal is to inspire a more intense interdisciplinary collaboration across the fields to further advance and progress non-invasive MR methods that ultimately support thorough (pathophysiological characterization of animal disease models. In this review, current and potential future applications for the RF coil technology in cardiovascular, neurovascular and renal disease will be discussed.

  2. Advance in quantitatively diagnosing and staging liver fibrosis with magnetic resonance imaging

    International Nuclear Information System (INIS)

    Liver fibrosis is the common characteristic of all kinds of chronic liver diseases, and early quantitative diagnosis of the fibrosis is of great significance for the choice of therapeutic methods and the promotion of this disease inversion. Liver biopsy is the gold standard for the diagnosis of liver fibrosis, but it is limited in clinical application due to its invasive nature. As a non-invasive examination method, magnetic resonance quantitative technique has progressed greatly in assessment of liver fibrosis in recent years. We will review the progress in the study on quantitatively diagnosing and staging liver fibrosis with magnetic resonance imaging. (authors)

  3. The OMERACT Magnetic Resonance Imaging Inflammatory Arthritis Group - advances and priorities

    DEFF Research Database (Denmark)

    Østergaard, Mikkel; McQueen, Fiona; Bird, Paul;

    2007-01-01

    This article updates the work and research priorities of the OMERACT working group on magnetic resonance imaging (MRI) in inflammatory arthritis, as presented to the OMERACT 8 meeting in Malta in May 2006. This work focused on testing the reliability of dedicated extremity MRI in rheumatoid arthr...

  4. The OMERACT Magnetic Resonance Imaging Inflammatory Arthritis Group - advances and priorities

    DEFF Research Database (Denmark)

    Østergaard, Mikkel; McQueen, Fiona; Bird, Paul; Peterfy, Charles; Haavardsholm, Espen; Ejbjerg, Bo; Lassere, Marissa; O'Connor, Philip; Emery, Paul; Edmonds, John; Genant, Harry; Conaghan, Philip G; NN, NN

    2007-01-01

    This article updates the work and research priorities of the OMERACT working group on magnetic resonance imaging (MRI) in inflammatory arthritis, as presented to the OMERACT 8 meeting in Malta in May 2006. This work focused on testing the reliability of dedicated extremity MRI in rheumatoid...... arthritis and on the initial steps in the development of an MRI score for peripheral psoriatic arthritis....

  5. Advanced echocardiography and cardiac magnetic resonance in congenital heart disease: insights in right ventricular mechanics and clinical implications

    OpenAIRE

    Hulst, Anna Elisabeth van der

    2011-01-01

    The thesis provides new insights into advanced echocardiographic and magnetic resonance imaging techniques for comprehensive mechanical assessment of the right ventricle in healthy children and in pediatric patients with right ventricular dysfunction. It is shown that the right ventricle does not contract synchronously in the longitudinal direction and that this is related to right ventricular function. Various echocardiographic (Tissue Doppler imaging, Speckle tracking, 3D echocardiography) ...

  6. 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 ...

  7. Parallel Magnetic Resonance Imaging

    CERN Document Server

    Uecker, Martin

    2015-01-01

    The main disadvantage of Magnetic Resonance Imaging (MRI) are its long scan times and, in consequence, its sensitivity to motion. Exploiting the complementary information from multiple receive coils, parallel imaging is able to recover images from under-sampled k-space data and to accelerate the measurement. Because parallel magnetic resonance imaging can be used to accelerate basically any imaging sequence it has many important applications. Parallel imaging brought a fundamental shift in image reconstruction: Image reconstruction changed from a simple direct Fourier transform to the solution of an ill-conditioned inverse problem. This work gives an overview of image reconstruction from the perspective of inverse problems. After introducing basic concepts such as regularization, discretization, and iterative reconstruction, advanced topics are discussed including algorithms for auto-calibration, the connection to approximation theory, and the combination with compressed sensing.

  8. Locally Advanced Prostate Cancer: Three-Dimensional Magnetic Resonance Spectroscopy to Monitor Prostate Response to Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Valentini, Anna Lia, E-mail: alvalentini@rm.unicatt.it [Department of Bioimaging and Radiological Sciences, Section of Radiology, Universita Cattolica del Sacro Cuore di Roma, Milan (Italy); Gui, Benedetta [Department of Bioimaging and Radiological Sciences, Section of Radiology, Universita Cattolica del Sacro Cuore di Roma, Milan (Italy); D' Agostino, Giuseppe Roberto; Mattiucci, Giancarlo [Department of Bioimaging and Radiological Sciences, Section of Radiotherapy, Universita Cattolica del Sacro Cuore di Roma, Milan (Italy); Clementi, Valeria [Clinical Science Development Group, GE Healthcare, Milan (Italy); Di Molfetta, Ippolita Valentina [Department of Bioimaging and Radiological Sciences, Section of Radiology, Universita Cattolica del Sacro Cuore di Roma, Milan (Italy); Bonomo, Pierluigi [OU Clinic Radiobiology, I.F.C.A. Florence (Italy); Mantini, Giovanna [Department of Bioimaging and Radiological Sciences, Section of Radiotherapy, Universita Cattolica del Sacro Cuore di Roma, Milan (Italy)

    2012-11-01

    Purpose: To correlate results of three-dimensional magnetic resonance spectroscopic imaging (MRSI) with prostate-specific antigen (PSA) levels and time since external beam irradiation (EBRT) in patients treated with long-term hormone therapy (HT) and EBRT for locally advanced disease to verify successful treatment by documenting the achievement of metabolic atrophy (MA). Methods and Materials: Between 2006 and 2008, 109 patients were consecutively enrolled. MA was assessed by choline and citrate peak area-to-noise-ratio <5:1. Cancerous metabolism (CM) was defined by choline-to-creatine ratio >1.5:1 or choline signal-to-noise-ratio >5:1. To test the strength of association between MRSI results and the time elapsed since EBRT (TEFRT), PSA levels, Gleason score (GS), and stage, logistic regression (LR) was performed. p value <0.05 was statistically significant. The patients' outcomes were verified in 2011. Results: MRSI documented MA in 84 of 109 and CM in 25 of 109 cases. LR showed that age, GS, stage, and initial and recent PSA had no significant impact on MRSI results which were significantly related to PSA values at the time of MRSI and to TEFRT. Patients were divided into three groups according to TEFRT: <1 year, 1-2 years, and >2 years. MA was detected in 54.1% of patients of group 1, 88.9% of group 2, and in 94.5% of group 3 (100% when PSA nadir was reached). CM was detected in 50% of patients with reached PSA nadir in group 1. Local relapse was found in 3 patients previously showing CM at long TEFRT. Conclusion: MA detection, indicative of successful treatment because growth of normal or abnormal cells cannot occur without metabolism, increases with decreasing PSA levels and increasing time on HT after EBRT. This supports long-term HT in advanced prostate cancer. Larger study series are needed to assess whether MRSI could predict local relapse by detecting CM at long TEFRT.

  9. Advancement of 31P Magnetic Resonance Spectroscopy Using GRAPPA Reconstruction on a 3D Volume

    Science.gov (United States)

    Clevenger, Tony

    The overall objective of this research is to improve currently available metabolic imaging techniques for clinical use in monitoring and predicting treatment response to radiation therapy in liver cancer. Liver metabolism correlates with inflammatory and neoplastic liver diseases, which alter the intracellular concentration of phosphorus- 31 (31P) metabolites [1]. It is assumed that such metabolic changes occur prior to physical changes of the tissue. Therefore, information on regional changes of 31P metabolites in the liver, obtained by Magnetic Resonance Spectroscopic Imaging (MRSI) [1,2], can help in diagnosis and follow-up of various liver diseases. Specifically, there appears to be an immediate need of this technology for both the assessment of tumor response in patients with Hepatocellular Carcinoma (HCC) treated with Stereotactic Body Radiation Therapy (SBRT) [3--5], as well as assessment of radiation toxicity, which can result in worsening liver dysfunction [6]. Pilot data from our lab has shown that 31P MRSI has the potential to identify treatment response five months sooner than conventional methods [7], and to assess the biological response of liver tissue to radiation 24 hours post radiation therapy [8]. While this data is very promising, commonly occurring drawbacks for 31P MRSI are patient discomfort due to long scan times and prone positioning within the scanner, as well as reduced data quality due to patient motion and respiration. To further advance the full potential of 31P MRSI as a clinical diagnostic tool in the management of liver cancer, this PhD research project had the following aims: I) Reduce the long acquisition time of 3D 31P MRS by formulating and imple- menting an appropriate GRAPPA undersampling scheme and reconstruction on a clinical MRI scanner II) Testing and quantitative validation of GRAPPA reconstruction on 3D 31P MRSI on developmental phantoms and healthy volunteers At completion, this work should considerably advance 31P MRSI

  10. Magnetic resonance enterography in Crohn’s disease: Standard and advanced techniques

    OpenAIRE

    Kayhan, Arda; Oommen, Jacob; Dahi, Farid; Oto, Aytekin

    2010-01-01

    Crohn’s disease (CD) is a chronic autoimmune disorder that affects mainly young people. The clinical management is based on the Crohn’s Disease Activity Index and especially on biologic parameters with or without additional endoscopic and imaging procedures, such as barium and computed tomography examinations. Recently, magnetic resonance (MR) imaging has been a promising diagnostic radiologic technique with lack of ionizing radiation, enabling superior tissue contrast resolution due to new p...

  11. Recent Advances of MEMS Resonators for Lorentz Force Based Magnetic Field Sensors: Design, Applications and Challenges.

    Science.gov (United States)

    Herrera-May, Agustín Leobardo; Soler-Balcazar, Juan Carlos; Vázquez-Leal, Héctor; Martínez-Castillo, Jaime; Vigueras-Zuñiga, Marco Osvaldo; Aguilera-Cortés, Luz Antonio

    2016-01-01

    Microelectromechanical systems (MEMS) resonators have allowed the development of magnetic field sensors with potential applications such as biomedicine, automotive industry, navigation systems, space satellites, telecommunications and non-destructive testing. We present a review of recent magnetic field sensors based on MEMS resonators, which operate with Lorentz force. These sensors have a compact structure, wide measurement range, low energy consumption, high sensitivity and suitable performance. The design methodology, simulation tools, damping sources, sensing techniques and future applications of magnetic field sensors are discussed. The design process is fundamental in achieving correct selection of the operation principle, sensing technique, materials, fabrication process and readout systems of the sensors. In addition, the description of the main sensing systems and challenges of the MEMS sensors are discussed. To develop the best devices, researches of their mechanical reliability, vacuum packaging, design optimization and temperature compensation circuits are needed. Future applications will require multifunctional sensors for monitoring several physical parameters (e.g., magnetic field, acceleration, angular ratio, humidity, temperature and gases). PMID:27563912

  12. Recent Advances of MEMS Resonators for Lorentz Force Based Magnetic Field Sensors: Design, Applications and Challenges

    Directory of Open Access Journals (Sweden)

    Agustín Leobardo Herrera-May

    2016-08-01

    Full Text Available Microelectromechanical systems (MEMS resonators have allowed the development of magnetic field sensors with potential applications such as biomedicine, automotive industry, navigation systems, space satellites, telecommunications and non-destructive testing. We present a review of recent magnetic field sensors based on MEMS resonators, which operate with Lorentz force. These sensors have a compact structure, wide measurement range, low energy consumption, high sensitivity and suitable performance. The design methodology, simulation tools, damping sources, sensing techniques and future applications of magnetic field sensors are discussed. The design process is fundamental in achieving correct selection of the operation principle, sensing technique, materials, fabrication process and readout systems of the sensors. In addition, the description of the main sensing systems and challenges of the MEMS sensors are discussed. To develop the best devices, researches of their mechanical reliability, vacuum packaging, design optimization and temperature compensation circuits are needed. Future applications will require multifunctional sensors for monitoring several physical parameters (e.g., magnetic field, acceleration, angular ratio, humidity, temperature and gases.

  13. Monitoring by nuclear magnetic resonance imaging in combined radio- and chemotherapy of advanced bladder carcinomas - first results

    International Nuclear Information System (INIS)

    A combination of cis-platinum and radiotherapy was applied in five patients with advanced bladder carcinomas. The patients were examined by nuclear magnetic resonance imaging prior to and following to therapy. Corresponding to cellcinetic considerations regarding tissues with slow cell turnover, a maximum therapy effect is shown about nine months after the end of local therapy. Smaller control intervals are recommended in case of bladder carcinomas with lymph node metastases. Due to the possibility of multiple slice imaging, the nuclear magnetic resonance technique is particularly suited for the monitoring of bladder carcinomas. Sagittal and coronary slices show a better image of tumoral extension at the roof and floor of the bladder than axial computed tomography. Lymph node metastases are represented relatively late by both methods. (orig.)

  14. Impact of Resonant Magnetic Perturbation Fields on NSTX-U Advanced Divertor Topologies

    Science.gov (United States)

    Waters, Ian; Frerichs, Heinke; Schmitz, Oliver; Ahn, Joon-Wook; Canal, Gustavo; Evans, Todd; Soukhanovskii, Vlad

    2015-11-01

    Explorations are under way to optimize the magnetic topology in the plasma edge of NSTX-U with the goal of improving neutral and impurity fueling and exhaust. The use of magnetic perturbation fields is being considered to spread heat and particle fluxes in the divertor, adjust plasma refueling, control impurity transport, and improve coupling to the exhaust systems. Also, advanced divertor configurations are being considered to improve peak heat loads on divertors. An assessment is made of the topologies of a number of representative NSTX-U advanced divertor configurations: lower single null, exact snowflake, and snowflake minus. Wall to wall magnetic connection lengths for each configuration are assessed in both their perturbed and axisymmetric configurations with perturbation coil currents of 1kA and 3kA. The magnetic perturbations yield complex strike patterns on divertor elements that are expected to be resolvable experimentally. The EMC3-EIRENE fluid plasma and kinetic neutral transport code will be used to study neutral and impurity transport and exhaust in these topologies. This work was funded in part by the Department of Energy under grant DE-SC0012315 and by startup funds of the Department of Engineering Physics at the University of Wisconsin-Madison.

  15. Magnetic Resonance Imaging (MRI)

    Science.gov (United States)

    ... Resonance Imaging (MRI) What is an MRI? MRI stands for Magnetic Resonance Imaging. It is an important ... MRI is often used for diagnosis or for monitoring disease. For example, if someone is having severe ...

  16. Vascular function assessed with cardiovascular magnetic resonance predicts survival in patients with advanced chronic kidney disease

    Directory of Open Access Journals (Sweden)

    Steedman Tracey

    2008-08-01

    Full Text Available Abstract Background Increased arterial stiffness is associated with mortality in patients with chronic kidney disease. Cardiovascular magnetic resonance (CMR permits assessment of the central arteries to measure aortic function. Methods We studied the relationship between central haemodynamics and outcome using CMR in 144 chronic kidney disease patients with estimated glomerular filtration rate Results Median follow up after the scan was 24 months. There were no significant differences in aortic distensibilty or aortic volumetric arterial strain between pre-dialysis and dialysis patients. Aortic distensibilty and volumetric arterial strain negatively correlated with age. Aortic distensibilty and volumetric arterial strain were lower in diabetics, patients with ischaemic heart disease and peripheral vascular disease. During follow up there were 20 deaths. Patients who died had lower aortic distensibilty than survivors. In a survival analysis, diabetes, systolic blood pressure and aortic distensibilty were independent predictors of mortality. There were 12 non-fatal cardiovascular events during follow up. Analysing the combined end point of death or a vascular event, diabetes, aortic distensibilty and volumetric arterial strain were predictors of events. Conclusion Deranged vascular function measured with CMR correlates with cardiovascular risk factors and predicts outcome. CMR measures of vascular function are potential targets for interventions to reduce cardiovascular risk.

  17. 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...

  18. 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.

  19. Chemical structures of swine-manure chars produced under different carbonization conditions investigated by advanced solid-state 13C nuclear magnetic resonance (NMR) spectroscopy

    Science.gov (United States)

    Two types of swine manure chars, hydrothermally-produced hydrochar and slow-pyrolysis pyrochar, and their raw swine manure solid were characterized using advanced 13C solid-state nuclear magnetic resonance (NMR) spectroscopy. Compared with the parent raw swine manure, both hydrochars and pyrochar di...

  20. Ultrasonography and magnetic resonance imaging in early rheumatoid arthritis: recent advances

    DEFF Research Database (Denmark)

    Østergaard, Mikkel; Døhn, Uffe M; Ejbjerg, Bo J;

    2006-01-01

    Efficient methods for diagnosis, monitoring, and prognostication are essential in early rheumatoid arthritis. Data on the value of ultrasonography and MRI are accumulating rapidly, fueling their increasing use in early rheumatoid arthritis. This review focuses on recent advances in the clinical...

  1. 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…

  2. 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

  3. 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 ...

  4. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... during MRI, but this is rarely a problem. Tooth fillings and braces usually are not affected by ... Magnetic Resonance Imaging (MRI) Safety Alzheimer's Disease Head Injury Brain Tumors Images related to Magnetic Resonance Imaging ( ...

  5. 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 ( ...

  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. Advanced characterization of pores and fractures in coals by nuclear magnetic resonance and X-ray computed tomography

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    This paper demonstrates capabilities of low-field nuclear magnetic resonance (NMR) and microfocus X-ray computed tomography (μCT) in advanced, nondestructive, and quantitative characterization of pore types, producible porosity, pore structure, and spatial disposition of pore-fractures in coals. Results show that the NMR transverse relaxation time (T2) at 0.5–2.5, 20–50, and >100 ms correspond to pores of <0.1 μm, >0.1 μm, and fractures, respectively. A much higher T2 spectrum peak reflects a much better development of pores (or fractures) corresponding to the T2, and vice versa. Three basic components in coals, i.e., the pores (or fractures), coal matrix, and minerals have their distinctive range of CT numbers. Among these, the CT number of pores is commonly less than 600 HU. The producible porosity, which is a determination of permeability, can be calculated by T2 cutoff value (T2C) of coal NMR. The coal pore structure can be efficiently estimated by the newly proposed "T2C based model". Finally, μCT scan was proven capable of modeling and spatial visualization of pores and fractures.

  8. the Diagnostic Value of Brain Magnetic Resonance imaging in Detecting CNS Diseases Among Advanced AiDS Patients

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    Objective To investigate the diagnostic value of brain magnetic resonance imaging in detecting central nervous system diseases among AIDS patients of different levels of T cells. Methods Total of 164 AIDS patients who did not receive antiviral treatment were divided into 2 groups according to their baseline CD4+T cell counts. Group A had CD4+T cell below or equal to 50 cells/μl (n=81) and group B had CD4+T cells over 50 cells/μl (n=83). All patients underwent brain MRI scan. Imaging analysis and the prevalence of the central nervous system disorders were compared between two groups. Results Among them 48 cases were found of abnormal brain MRI, group A was higher than group B (35.8%vs. 22.9%) although without statistical significance (P = 0.065). Altogether 48 cases were diagnosed as AIDS related central nervous system disorders based on clinical symptoms, signs and laboratory findings. The prevalence of CNS disorders was higher in group A than in group B (41.9%vs. 16.8%) with statistical significance (P<0.01). Conclusions The patients with CD4+T cell count less than or equal to 50 cells/μl had high prevalence of CNS diseases. Brain MRI plays an important role in the diagnosis and differentiation of CNS diseases in advanced AIDS patients. This study suggests patients with low CD4+T cell count (≤ 50/μl) should routinely undergo MRI examination.

  9. 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...

  10. 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 ...

  11. 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 ...

  12. 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 ...

  13. Advanced Magnetic Nanostructures

    CERN Document Server

    Sellmyer, David

    2006-01-01

    Advanced Magnetic Nanostructures is devoted to the fabrication, characterization, experimental investigation, theoretical understanding, and utilization of advanced magnetic nanostructures. Focus is on various types of 'bottom-up' and 'top-down' artificial nanostructures, as contrasted to naturally occurring magnetic nanostructures, such as iron-oxide inclusions in magnetic rocks, and to structures such as perfect thin films. Chapter 1 is an introduction into some basic concepts, such as the definitions of basic magnetic quantities. Chapters 2-4 are devoted to the theory of magnetic nanostructures, Chapter 5 deals with the characterization of the structures, and Chapters 6-10 are devoted to specific systems. Applications of advanced magnetic nanostructures are discussed in Chapters11-15 and, finally, the appendix lists and briefly discusses magnetic properties of typical starting materials. Industrial and academic researchers in magnetism and related areas such as nanotechnology, materials science, and theore...

  14. Advanced Imaging (Positron Emission Tomography and Magnetic Resonance Imaging) and Image-Guided Biopsy in Initial Staging and Monitoring of Therapy of Lung Cancer

    OpenAIRE

    Islam, Shaheen; Walker, Ronald C.

    2013-01-01

    The results of the National Lung Screening Trial strongly support early detection and definitive treatment to reduce lung cancer mortality. Once lung cancer is discovered, accurate staging at baseline is imperative to maximize patient benefit and cost-effective use of health care resources. Although computed tomography (CT) remains a powerful tool for staging of lung cancer, advances in other imaging modalities, specifically positron emission tomography/CT and magnetic resonance imaging, can ...

  15. Abnormal T2-STIR Magnetic Resonance in Hypertrophic Cardiomyopathy: A Marker of Advanced Disease and Electrical Myocardial Instability

    Science.gov (United States)

    Pisciella, Lorena; Barison, Andrea; Del Franco, Annamaria; Zachara, Elisabetta; Piaggi, Paolo; Re, Federica; Pingitore, Alessandro; Emdin, Michele; Lombardi, Massimo

    2014-01-01

    Background Myocardial hyperintensity on T2-weighted short-tau inversion recovery (STIR) (HyT2) cardiac magnetic resonance (CMR) images has been demonstrated in patients with hypertrophic cardiomyopathy (HCM) and is considered a sign of acute damage. The aim of the current study was to evaluate the relationship between HyT2 and both a) markers of ventricular electrical instability and b) clinical and CMR parameters. Methods Sixty-five patients underwent a thorough clinical examination, consisting of 24-h ECG recording and CMR examination including functional evaluation, T2-STIR images and late gadolinium enhancement (LGE). Results HyT2 was detected in 27 patients (42%), and subjects with HyT2 showed a greater left ventricle (LV) mass index (p<0.001), lower LV ejection fraction (p = 0.05) and greater extent of LGE (p<0.001) compared to those without HyT2. Twenty-two subjects (34%) presented non-sustained ventricular tachycardia (NSVT) on the 24-h ECG recording, 21 (95%) of whom exhibited HyT2. Based on the logistic regression analysis, HyT2 (odds ratio [OR]: 165, 95% CI 11–2455, p<0.001) and LGE extent (1.1, 1.0–1.3, p<0.001) served as independent predictors of NSVT, while the presence of LGE was not associated with NSVT occurrence (p = 0.49). The presence of HyT2 was associated with lower heart rate variability (p = 0.006) and a higher number of arrhythmic risk factors (p<0.001). Conclusions In HCM patients, HyT2 upon CMR examination is associated with more advanced disease and increased arrhythmic burden. PMID:25356653

  16. Advances in the Understanding of ELM Suppression by Resonant Magnetic Perturbations (RMPs) in DIII-D and Implications for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Nazikian, R. [PPPL

    2014-09-01

    Experiments on DIII-D have expanding the operating window for RMP ELM suppression to higher q95 with dominant electron heating and fully non-inductive current drive relevant to advanced modes of ITER operation. Robust ELM suppression has also been obtained with a reduced coil set, mitigating the risk of coil failure in maintaining ELM suppression in ITER. These results significantly expand the operating space and reduce risk for obtaining RMP ELM suppression in ITER. Efforts have also been made to search for 3D cause of ELM suppression. No internal non-axisymmetric structure is detected at the top of the pedestal, indicating that the dominant effect of the RMP is to produce an n=0 transport modification of the profiles. Linear two fluid MHD simulations using M3D-C1 indicate resonant field penetration and significant magnetic stochasticity at the top of the pedestal, consistent with the absence of detectable 3D structure in that region. A profile database was developed to compare the scaling of the pedestal and global confinement with the applied 3D field strength in ELM suppressed and ELM mitigated plasmas. The EPED pedestal model accurately predicts the measured pedestal pressure at the threshold of ELM suppression, increasing confidence in theoretical projections to ITER pedestal conditions. Both the H-factor (H(sub)98y2) and thermal energy confinement time do not degrade substantially with applied RMP fields near the threshold of ELM suppression, enhancing confidence in the compatibility of ITER high performance operation with RMP ELM suppression.

  17. Cavity- and waveguide-resonators in electron paramagnetic resonance, nuclear magnetic resonance, and magnetic resonance imaging.

    Science.gov (United States)

    Webb, Andrew

    2014-11-01

    Cavity resonators are widely used in electron paramagnetic resonance, very high field magnetic resonance microimaging and also in high field human imaging. The basic principles and designs of different forms of cavity resonators including rectangular, cylindrical, re-entrant, cavity magnetrons, toroidal cavities and dielectric resonators are reviewed. Applications in EPR and MRI are summarized, and finally the topic of traveling wave MRI using the magnet bore as a waveguide is discussed. PMID:25456314

  18. Cardiovascular magnetic resonance of the right ventricle

    OpenAIRE

    Alpendurada, Francisco Diogo

    2013-01-01

    Introduction: Whilst most of the attention has been devoted to the left ventricle in cardiovascular disease, the right ventricle has been somewhat neglected. In the last decades, there has been a renewal of interest in the right ventricle, in part driven by advances in cardiovascular imaging. Methods: Cardiovascular magnetic resonance is arguably the best imaging modality for the study of the right ventricle. In this research thesis, cardiovascular magnetic resonance w...

  19. 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.

  20. 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 ...

  1. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses a powerful magnetic ... that are clearer and more detailed than other imaging methods. This exam does not use ionizing radiation ...

  2. 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

  3. 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.

  4. 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.)

  5. Spinal Cord Segmentation by One Dimensional Normalized Template Matching: A Novel, Quantitative Technique to Analyze Advanced Magnetic Resonance Imaging Data.

    Science.gov (United States)

    Cadotte, Adam; Cadotte, David W; Livne, Micha; Cohen-Adad, Julien; Fleet, David; Mikulis, David; Fehlings, Michael G

    2015-01-01

    Spinal cord segmentation is a developing area of research intended to aid the processing and interpretation of advanced magnetic resonance imaging (MRI). For example, high resolution three-dimensional volumes can be segmented to provide a measurement of spinal cord atrophy. Spinal cord segmentation is difficult due to the variety of MRI contrasts and the variation in human anatomy. In this study we propose a new method of spinal cord segmentation based on one-dimensional template matching and provide several metrics that can be used to compare with other segmentation methods. A set of ground-truth data from 10 subjects was manually-segmented by two different raters. These ground truth data formed the basis of the segmentation algorithm. A user was required to manually initialize the spinal cord center-line on new images, taking less than one minute. Template matching was used to segment the new cord and a refined center line was calculated based on multiple centroids within the segmentation. Arc distances down the spinal cord and cross-sectional areas were calculated. Inter-rater validation was performed by comparing two manual raters (n = 10). Semi-automatic validation was performed by comparing the two manual raters to the semi-automatic method (n = 10). Comparing the semi-automatic method to one of the raters yielded a Dice coefficient of 0.91 +/- 0.02 for ten subjects, a mean distance between spinal cord center lines of 0.32 +/- 0.08 mm, and a Hausdorff distance of 1.82 +/- 0.33 mm. The absolute variation in cross-sectional area was comparable for the semi-automatic method versus manual segmentation when compared to inter-rater manual segmentation. The results demonstrate that this novel segmentation method performs as well as a manual rater for most segmentation metrics. It offers a new approach to study spinal cord disease and to quantitatively track changes within the spinal cord in an individual case and across cohorts of subjects. PMID:26445367

  6. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... or cause problems during an MRI exam. Nephrogenic systemic fibrosis is currently a recognized, but rare, complication ... Tumor Treatment Magnetic Resonance Imaging (MRI) Safety Alzheimer's Disease Head Injury Brain Tumors Images related to Magnetic ...

  7. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... the same effect. A very irregular heartbeat may affect the quality of images obtained using techniques that ... Tumor Treatment Magnetic Resonance Imaging (MRI) Safety Alzheimer's Disease Head Injury Brain Tumors Images related to Magnetic ...

  8. 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)

  9. 网络游戏成瘾的磁共振研究进展%Advancement in the Research on Magnetic Resonance Imaging of Internet Game Addiction

    Institute of Scientific and Technical Information of China (English)

    秦燕; 刘军; 周顺科

    2013-01-01

    After reviewing the related literatures,this paper summarizes the advancement in internet game addiction research mainly with regards to these three aspects:the basic principles and applications of functional magnetic resonance,brain structural magnetic resonance of internet game addiction and brain functional magnetic resonance of internet game addiction.%网络游戏成瘾(internet game addiction,IGA)给青少年带来的各种行为异常、心理及人格障碍以及神经功能紊乱等消极后果,越来越多地引起了心理学家、医务工作者、教育工作者及全社会的普遍关注.本文通过回顾分析文献就功能磁共振基本原理及应用、网络游戏成瘾脑结构和脑功能磁共振研究三方面综述网络游戏成瘾的研究进展.

  10. 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) - Head Magnetic resonance imaging (MRI) of the head uses a ...

  11. Magnetic resonance imaging methodology

    International Nuclear Information System (INIS)

    Magnetic resonance (MR) methods are non-invasive techniques to provide detailed, multi-parametric information on human anatomy, function and metabolism. Sensitivity, specificity, spatial and temporal resolution may, however, vary depending on hardware (e.g., field strength, gradient strength and speed) and software (optimised measurement protocols and parameters for the various techniques). Furthermore, multi-modality imaging may enhance specificity to better characterise complex disease patterns. Positron emission tomography (PET) is an interesting, largely complementary modality, which might be combined with MR. Despite obvious advantages, combining these rather different physical methods may also pose challenging problems. At this early stage, it seems that PET quality may be preserved in the magnetic field and, if an adequate detector material is used for the PET, MR sensitivity should not be significantly degraded. Again, this may vary for the different MR techniques, whereby functional and metabolic MR is more susceptible than standard anatomical imaging. Here we provide a short introduction to MR basics and MR techniques, also discussing advantages, artefacts and problems when MR hardware and PET detectors are combined. In addition to references for more detailed descriptions of MR fundamentals and applications, we provide an early outlook on this novel and exciting multi-modality approach to PET/MR. (orig.)

  12. Recent advances in the data analysis method of functional magnetic resonance imaging and its applications in neuroimaging

    Institute of Scientific and Technical Information of China (English)

    TIAN Jie; YANG Lei; HU Jin

    2006-01-01

    Functional magnetic resonance imaging (fMRI) has opened a new area to explore the human brain. The fMRI can reveal the deep insights of spatial and temporal changes underlying a broad range of brain function, such as motor, vision, memory and emotion, all of which are helpful in the clinical investigation. In this paper, we introduce some recent-developed algorithms for fMRI signal detection such as model-driven method (general linear model, deconvolution model, non-linear model, etc. ) and data-driven method (principle component analysis, independent component analysis, self-organization mapping, clustered constrained non-negative matrix factorization, etc. ). We also propose several important applications of neuroimaging and point out their shortcomings and future perspectives.

  13. 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.)

  14. Magnetic Resonance angiography. Pt 1

    International Nuclear Information System (INIS)

    The objective of this paper is to describe the basic physical principles important in magnetic resonance angiography (MRA). The data used were obtained from recent articles on MRA and direct experience working with prototype MRA sequence. The information is presented in a manner suitable for those unfamiliar with the principles of MRA and magnetic resonance imaging (MRI). Magnetic resonance angiography is an important method that can be used to obtain angiograms without the injection of intravascular contrast medium. It is already proving to be of clinical use in the assessment of vascular disease. 11 refs., 5 figs

  15. 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

  16. 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. PMID:26878709

  17. Nuclear magnetic resonance as a petrophysical measurement

    International Nuclear Information System (INIS)

    Nuclear magnetic resonance (NMR) of hydrogen nuclei in fluids which saturate porous rocks is important in oil exploration and production, since NMR logs can provide good estimates of permeability and fluid flow. This paper reviews developments which connect the NMR properties of rocks with petrophysical properties, and particularly those relating to fluid flow. The recent advances in the use of NMR in boreholes which have spurred these developments are also discussed. The relevance of other NMR measurements on geological samples, including magnetic resonance imaging, is briefly referred to. (author)

  18. 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) - ...

  19. 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 ...

  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 ... Head? Magnetic resonance imaging (MRI) is a noninvasive medical test that physicians use to diagnose and treat ...

  1. 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...

  2. Magnetic Resonance Connectome Automated Pipeline

    OpenAIRE

    Gray, William R.; Bogovic, John A.; Vogelstein, Joshua T; Landman, Bennett A.; Prince, Jerry L.; Vogelstein, R. Jacob

    2011-01-01

    This manuscript presents a novel, tightly integrated pipeline for estimating a connectome, which is a comprehensive description of the neural circuits in the brain. The pipeline utilizes magnetic resonance imaging (MRI) data to produce a high-level estimate of the structural connectivity in the human brain. The Magnetic Resonance Connectome Automated Pipeline (MRCAP) is efficient and its modular construction allows researchers to modify algorithms to meet their specific requirements. The pipe...

  3. 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.

  4. Nuclear magnetic gamma double resonance

    International Nuclear Information System (INIS)

    A number of problems corresponding to different variants of experiments using nuclear magnetic-gamma double resonance (NMGDR) are theoretically investigated. Calculation is carried out and its results are compared to experimental ones concerning NMGDR for tantalum. Time dynamics of the source or scatterer nucleus sublevel populations under double resonance conditions with non-uniform initial population of this nucleus sublevels is studied

  5. Magnetic resonance imaging; Imagerie par resonance magnetique

    Energy Technology Data Exchange (ETDEWEB)

    Fontanel, F. [Centre Hospitalier, 40 - Mont-de -Marsan (France); Clerc, T. [Centre Hospitalier Universitaire, 76 - Rouen (France); Theolier, S. [Hospice Civils de Lyon, 69 - Lyon (France); Verdenet, J. [Centre Hospitalier Universitaire, 25 - Besancon (France)

    1997-04-01

    The last improvements in nuclear magnetic resonance imaging are detailed here, society by society with an expose of their different devices. In the future the different technological evolutions will be on a faster acquisition, allowing to reduce the examination time, on the development of a more acute cardiac imaging, of a functional neuro-imaging and an interactive imaging for intervention. With the contrast products, staying a longer time in the vascular area, the angiography will find its place. Finally, the studies on magnetic fields should allow to increase the volume to examine. (N.C.).

  6. 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)

  7. Diffusion-weighted magnetic resonance imaging during radiotherapy of locally advanced cervical cancer - treatment response assessment using different segmentation methods

    DEFF Research Database (Denmark)

    Haack, Søren; Tanderup, Kari; Kallehauge, Jesper Folsted;

    2015-01-01

    BACKGROUND: Diffusion-weighted magnetic resonance imaging (DW-MRI) and the derived apparent diffusion coefficient (ADC) value has potential for monitoring tumor response to radiotherapy (RT). Method used for segmentation of volumes with reduced diffusion will influence both volume size and observed...... volumes changed significantly during treatment (p < 0.01). There was a significant difference in JSI among segmentation methods at time of PRERT (p < 0.016) with region growing having the lowest JSIGTV (mean± sd: 0.35 ± 0.1), followed by the SD4 method (mean± sd: 0.50 ± 0.1) and clustering (mean± sd: 0.......52 ± 0.3). There was no significant difference in mean ADC value compared at same treatment time. Mean tumor ADC value increased significantly (p < 0.01) for all methods across treatment time. CONCLUSION: Among the three semi-automatic segmentations of hyper-intense intensities on DW-MR images...

  8. Handbook of Advanced Magnetic Materials

    CERN Document Server

    Liu, Yi; Shindo, Daisuke

    2006-01-01

    From high-capacity, inexpensive hard drives to mag-lev trains, recent achievements in magnetic materials research have made the dreams of a few decades ago reality. The objective of Handbook of Advanced Magnetic Materials is to provide a timely, comprehensive review of recent progress in magnetic materials research. This broad yet detailed reference consists of four volumes: 1.) Nanostructured advanced magnetic materials, 2.) Characterization and simulation of advanced magnetic materials, 3.) Processing of advanced magnetic materials, and 4.) Properties and applications of advanced magnetic materials The first volume documents and explains recent development of nanostructured magnetic materials, emphasizing size effects. The second volume provides a comprehensive review of both experimental methods and simulation techniques for the characterization of magnetic materials. The third volume comprehensively reviews recent developments in the processing and manufacturing of advanced magnetic materials. With the co...

  9. 青少年抑郁症的功能磁共振研究进展%Advances of functional magnetic resonance imaging in adolescent depressive disorder

    Institute of Scientific and Technical Information of China (English)

    孙雅文

    2011-01-01

    近年来功能磁共振成像在成人抑郁症中的研究较为深入,而对于青少年抑郁症的研究则相对有限,故本文就目前功能性磁共振在青少年抑郁症中的研究进展作一综述.%In recent years, functional magnetic resonance imaging (fMRD studies have led to a deeper understanding of major depressive disorder (MDD) in adult. In contrast, our current study of adolescent MDD is very limited. This article reviews the advanced applications of the current fMRI in adolescent MDD.

  10. Magnetic resonance and porous materials

    International Nuclear Information System (INIS)

    Mention the words magnetic resonance to your medical advisor and he or she will immediately think of a multi-million pound scanner that peers deep into the brain. A chemist, on the other hand, will imagine a machine that costs several hundred thousand pounds and produces high-resolution spectra for chemical analysis. Food technologists will probably think of a bench-top instrument for determining moisture content, while an oil prospector will envisage a device that can be operated several kilometres down an oil well. To a physicist the term is more likely to conjure up a mental picture of nuclear spins precessing in a magnetic field. These examples illustrate the diverse aspects of a phenomenon discovered by physicists over 50 years ago. Electron spin resonance was first discovered by Russian scientists, and nuclear magnetic resonance was discovered in the US shortly afterwards by Ed Purcell at Harvard University and Felix Bloch at Stanford University. Today, nuclear magnetic resonance (NMR) is the most widely used technique. Modern NMR machines are making it possible to probe microstructure and molecular movement in materials as diverse as polymers, cements, rocks, soil and foods. NMR allows the distribution of different components in a material to be determined with a resolution approaching 1μm, although the signal can be sensitive to even smaller lengthscales. In this article the authors describe how physicists are still developing magnetic resonance to exploit a range of new applications. (UK)

  11. 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.

  12. 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.)

  13. 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)

  14. 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 ...

  15. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... Safety En Español More Info Images/Videos News Physician Resources Professions Site Index A-Z Magnetic Resonance ... allergic reaction than iodinated contrast material. Tell your doctor about any health problems, recent surgeries or allergies ...

  16. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... Español More Info Images/Videos News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - ... into the bloodstream. The radiologist , technologist or a nurse may ask if you have allergies of any ...

  17. 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.

  18. 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)

  19. 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 ...

  20. 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.

  1. 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

  2. Imaging in rheumatoid arthritis--status and recent advances for magnetic resonance imaging, ultrasonography, computed tomography and conventional radiography

    DEFF Research Database (Denmark)

    Østergaard, Morten; Dohn, U.M.; Østergaard, Mikkel;

    2008-01-01

    , and have several documented and potential applications in RA patients. This chapter will review key aspects of the current status and recent important advances in imaging in RA, briefly discussing X-ray and computed tomography, and particularly focusing on MRI and US. Suggestions for use in clinical trials...

  3. Resonant magnetic fields from inflation

    International Nuclear Information System (INIS)

    We propose a novel scenario to generate primordial magnetic fields during inflation induced by an oscillating coupling of the electromagnetic field to the inflaton. This resonant mechanism has two key advantages over previous proposals. First of all, it generates a narrow band of magnetic fields at any required wavelength, thereby allaying the usual problem of a strongly blue spectrum and its associated backreaction. Secondly, it avoids the need for a strong coupling as the coupling is oscillating rather than growing or decaying exponentially. Despite these major advantages, we find that the backreaction is still far too large during inflation if the generated magnetic fields are required to have a strength of O(10−15 Gauss) today on observationally interesting scales. We provide a more general no-go argument, proving that this problem will apply to any model in which the magnetic fields are generated on subhorizon scales and freeze after horizon crossing

  4. 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

  5. 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....

  6. Tomography by nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Imaging methods based on nuclear magnetic resonance allow the production of sectional images of the human body without ionizing radiation. It is possible to measure the density and relaxation times of the water protons in body fluids or tissue. This allows not only to obtain morphological information but also to get some insight into the spatial distribution of physiological data. Starting with a review of the principles of nuclear magnetic resonance it is explained how the measured signal can be associated with an image point; it is also explained what type of apparatus is necessary and what the physical limitations are. Possible risks the patient may be exposed to in an examination using nuclear magnetic resonance are discussed. The present state of the technical development enables the production of whole-body sectional images of a living person within about one minute. By means of some typical examples the nature and properties of these images are explained. Although extensive clinical studies will be necessary before a more general assessment can be made of this method, an outlook is provided on expected further developments and possible future fields of application. (orig.)

  7. 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.

  8. Magnetic Resonance Force Detection using a Membrane Resonator

    OpenAIRE

    Scozzaro, Nicolas; Ruchotzke, Will; Belding, Amanda; Cardellino, Jeremy D.; Blomberg, Erick C.; McCullian, Brendan A.; Bhallamudi, Vidya P.; Pelekhov, Denis V.; Hammel, P. Chris

    2016-01-01

    The availability of compact, low-cost magnetic resonance imaging instruments would further broaden the substantial impact of this technology. We report highly sensitive detection of magnetic resonance using low-stress silicon nitride (SiN$_x$) membranes. We use these membranes as low-loss, high-frequency mechanical oscillators and find they are able to mechanically detect spin-dependent forces with high sensitivity enabling ultrasensitive magnetic resonance detection. The high force detection...

  9. 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...

  10. Magnetic resonance imaging in oncology

    International Nuclear Information System (INIS)

    Nuclear magnetic resonance (NMR) employs radio-frequency radiation in the presence of a static magnetic field to produce signals from naturally occurring nuclei in biological tissue. The information in magnetic resonance imaging (MRI) can be derived from these signals in any orthogonal plane. Hydrogen is the most abundant of such nuclei, occurring naturally in water and lipid, and can be detected at relatively low magnetic field strength (0.04 tesla (T) upwards). The MR signal from hydrogen depends not only on the proton density and the T1 and T2 relaxation times of those protons following radio-frequency pulse disturbances, but also on the timing parameters of the radio-frequency pulse sequences employed. Image contrast depends on the interaction between all these factors; not simply as in X-ray computed tomography (CT) on the properties of the tissue itself. Therefore an understanding of both the imaging process and the pathology under investigation is essential in the proper use of MRI

  11. Tracer kinetic model selection for dynamic contrast-enhanced magnetic resonance imaging of locally advanced cervical cancer

    DEFF Research Database (Denmark)

    Kallehauge, Jesper Folsted; Tanderup, Kari; Duan, Chong;

    2014-01-01

    conditions the Tofts (TM), extended Tofts (ETM), compartmental tissue uptake model (C-TU) and 2-compartment exchange model (2CXM) were the optimal tracer kinetic models (TKMs) for the analysis of DCE-MRI in patients with cervical cancer. Material and methods. Ten patients with locally advanced cervical......-treatment cervical cancers, although this model broke down in a subset of the tumour voxels where overfitting resulted in non-physiological parameter estimates. Due to the possible overfitting of the 2CXM, the C-TU was found more robust and when 2CXM was excluded from comparison the C-TU was the preferred model....... cancer (FIGO: IIA/IIB/IIIB/IVA-1/5/3/1) underwent DCE-MRI prior to radiotherapy. From the two-parameter TM it was possible to extract the forward volume transfer constant (Ktrans) and the extracellular-extravascular volume fraction (ve). From the three-parameter ETM, additionally the plasma volume...

  12. Fetal magnetic resonance imaging: methods and techniques

    International Nuclear Information System (INIS)

    Since the introduction of fetal magnetic resonance imaging (MRI) into prenatal diagnostics, advances in coil technology and development of ultrafast sequences have further enhanced this technique. At present numerous sequences are available to visualize the whole fetus with high resolution and image quality, even in late stages of pregnancy. Taking into consideration the special circumstances of examination and adjusting sequence parameters to gestational age, fetal anatomy can be accurately depicted. The variety of sequences also allows further characterization of fetal tissues and pathologies. Fetal MRI not only supplies additional information to routine ultrasound studies, but also reveals fetal morphology and pathology in a way hitherto not possible. (orig.)

  13. Aspects of postoperative magnetic resonance imaging of patients with avascular necrosis of the femoral head, treated by advanced core decompression

    International Nuclear Information System (INIS)

    To analyze remodeling processes after advanced core decompression (ACD) in patients with avascular femoral head necrosis by means of 3T MRI and to identify indicators for clinical outcome considering the defect size and characteristics of the bone graft and of the neighboring regeneration tissue. Thirty-four hips, with preexisting preoperative MRIs in 21 cases, were examined 1-34 months (mean 12.7) postoperatively by 3T MRI. The volume of necrosis was measured manually pre- and postoperatively to calculate absolute as well as percentage necrosis reduction. The signal intensity of the bone graft was quantified using a 4-point scale. Border phenomena between the bone graft and bone were described and classified into groups. Wilcoxon sign-rank test was used to identify correlations between the analyzed items and clinical signs of femoral head collapse after a mean follow-up time of 28.6 months (10.4-46.8). Mean percentage reduction of necrosis was significantly higher in asymptomatic patients (59.36 %) compared to patients with signs of femoral head collapse (28.78 %, p = 0.008). Signal intensity of the bone graft increased in T1w and T2w TIRM sequences over time after surgery and was significantly higher in asymptomatic patients. Five border phenomena between the bone graft and healthy bone were identified. Among them, the so-called ''rail sign'' representing three layers of remodeling tissue correlated with the histological observations. A variety of border phenomena representing remodeling processes have been described using 3T MRI. Beneath the percentage amount of necrosis reduction, we identified the signal intensity of the bone graft as an indicator for clinical outcome. (orig.)

  14. Aspects of postoperative magnetic resonance imaging of patients with avascular necrosis of the femoral head, treated by advanced core decompression

    Energy Technology Data Exchange (ETDEWEB)

    Lazik, Andrea; Lauenstein, Thomas C.; Theysohn, Jens M. [University Hospital Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Landgraeber, Stefan; Classen, Tim [University Hospital Essen, Department of Orthopedics, Essen (Germany); Kraff, Oliver [University of Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany)

    2015-10-15

    To analyze remodeling processes after advanced core decompression (ACD) in patients with avascular femoral head necrosis by means of 3T MRI and to identify indicators for clinical outcome considering the defect size and characteristics of the bone graft and of the neighboring regeneration tissue. Thirty-four hips, with preexisting preoperative MRIs in 21 cases, were examined 1-34 months (mean 12.7) postoperatively by 3T MRI. The volume of necrosis was measured manually pre- and postoperatively to calculate absolute as well as percentage necrosis reduction. The signal intensity of the bone graft was quantified using a 4-point scale. Border phenomena between the bone graft and bone were described and classified into groups. Wilcoxon sign-rank test was used to identify correlations between the analyzed items and clinical signs of femoral head collapse after a mean follow-up time of 28.6 months (10.4-46.8). Mean percentage reduction of necrosis was significantly higher in asymptomatic patients (59.36 %) compared to patients with signs of femoral head collapse (28.78 %, p = 0.008). Signal intensity of the bone graft increased in T1w and T2w TIRM sequences over time after surgery and was significantly higher in asymptomatic patients. Five border phenomena between the bone graft and healthy bone were identified. Among them, the so-called ''rail sign'' representing three layers of remodeling tissue correlated with the histological observations. A variety of border phenomena representing remodeling processes have been described using 3T MRI. Beneath the percentage amount of necrosis reduction, we identified the signal intensity of the bone graft as an indicator for clinical outcome. (orig.)

  15. 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 ...

  16. 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.

  17. 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...

  18. 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. PMID:26751800

  19. Chemical structures of coal lithotypes before and after CO2 adsorption as investigated by advanced solid-state 13C nuclear magnetic resonance spectroscopy

    Science.gov (United States)

    Cao, X.; Mastalerz, Maria; Chappell, M.A.; Miller, L.F.; Li, Y.; Mao, J.

    2011-01-01

    Four lithotypes (vitrain, bright clarain, clarain, and fusain) of a high volatile bituminous Springfield Coal from the Illinois Basin were characterized using advanced solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. The NMR techniques included quantitative direct polarization/magic angle spinning (DP/MAS), cross polarization/total sideband suppression (CP/TOSS), dipolar dephasing, CHn selection, and recoupled C-H long-range dipolar dephasing techniques. The lithotypes that experienced high-pressure CO2 adsorption isotherm analysis were also analyzed to determine possible changes in coal structure as a result of CO2 saturation at high pressure and subsequent evacuation. The main carbon functionalities present in original vitrain, bright clarain, clarain and fusain were aromatic carbons (65.9%-86.1%), nonpolar alkyl groups (9.0%-28.9%), and aromatic C-O carbons (4.1%-9.5%). Among these lithotypes, aromaticity increased in the order of clarain, bright clarain, vitrain, and fusain, whereas the fraction of alkyl carbons decreased in the same order. Fusain was distinct from other three lithotypes in respect to its highest aromatic composition (86.1%) and remarkably small fraction of alkyl carbons (11.0%). The aromatic cluster size in fusain was larger than that in bright clarain. The lithotypes studied responded differently to high pressure CO2 saturation. After exposure to high pressure CO2, vitrain and fusain showed a decrease in aromaticity but an increase in the fraction of alkyl carbons, whereas bright clarain and clarain displayed an increase in aromaticity but a decrease in the fraction of alkyl carbons. Aromatic fused-rings were larger for bright clarain but smaller for fusain in the post-CO2 adsorption samples compared to the original lithotypes. These observations suggested chemical CO2-coal interactions at high pressure and the selectivity of lithotypes in response to CO2 adsorption. ?? 2011 Elsevier B.V.

  20. Characterization of oil shale, isolated kerogen, and post-pyrolysis residues using advanced 13 solid-state nuclear magnetic resonance spectroscopy

    Science.gov (United States)

    Cao, Xiaoyan; Birdwell, Justin E.; Chappell, Mark A.; Li, Yuan; Pignatello, Joseph J.; Mao, Jingdong

    2013-01-01

    Characterization of oil shale kerogen and organic residues remaining in postpyrolysis spent shale is critical to the understanding of the oil generation process and approaches to dealing with issues related to spent shale. The chemical structure of organic matter in raw oil shale and spent shale samples was examined in this study using advanced solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. Oil shale was collected from Mahogany zone outcrops in the Piceance Basin. Five samples were analyzed: (1) raw oil shale, (2) isolated kerogen, (3) oil shale extracted with chloroform, (4) oil shale retorted in an open system at 500°C to mimic surface retorting, and (5) oil shale retorted in a closed system at 360°C to simulate in-situ retorting. The NMR methods applied included quantitative direct polarization with magic-angle spinning at 13 kHz, cross polarization with total sideband suppression, dipolar dephasing, CHn selection, 13C chemical shift anisotropy filtering, and 1H-13C long-range recoupled dipolar dephasing. The NMR results showed that, relative to the raw oil shale, (1) bitumen extraction and kerogen isolation by demineralization removed some oxygen-containing and alkyl moieties; (2) unpyrolyzed samples had low aromatic condensation; (3) oil shale pyrolysis removed aliphatic moieties, leaving behind residues enriched in aromatic carbon; and (4) oil shale retorted in an open system at 500°C contained larger aromatic clusters and more protonated aromatic moieties than oil shale retorted in a closed system at 360°C, which contained more total aromatic carbon with a wide range of cluster sizes.

  1. Diffusion-weighted magnetic resonance imaging for pretreatment prediction and monitoring of treatment response of patients with locally advanced breast cancer undergoing neoadjuvant chemotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Nilsen, Line; Olsen, Dag Rune; Seierstad, Therese (Inst. for Cancer Research, Oslo Univ. Hospital, Oslo (Norway)), E-mail: line.nilsen2@rr-research.no; Fangberget, Anne (Dept. of Radiology and Nuclear Medicine, Oslo Univ. Hospital, Oslo (Norway)); Geier, Oliver (Dept. of Medical Physics, Division of Cancer Medicine and Radiation Therapy, Oslo Univ. Hospital, Oslo (Norway))

    2010-04-15

    Background. For patients with locally advanced breast cancer (LABC) undergoing neoadjuvant chemotherapy (NACT), the European Guidelines for Breast Imaging recommends magnetic resonance imaging (MRI) to be performed before start of NACT, when half of the NACT has been administered and prior to surgery. This is the first study addressing the value of flow-insensitive apparent diffusion coefficients (ADCs) obtained from diffusion-weighted (DW) MRI at the recommended time points for pretreatment prediction and monitoring of treatment response. Materials and methods. Twenty-five LABC patients were included in this prospective study. DW MRI was performed using single-shot spin-echo echo-planar imaging with b-values of 100, 250 and 800 s/mm2 prior to NACT, after four cycles of NACT and at the conclusion of therapy using a 1.5 T MR scanner. ADC in the breast tumor was calculated from each assessment. The strength of correlation between pretreatment ADC, ADC changes and tumor volume changes were examined using Spearman's rho correlation test. Results. Mean pretreatment ADC was 1.11 +- 0.21 x 10-3 mm2/s. After 4 cycles of NACT, ADC was significantly increased (1.39 +- 0.36 x 10-3 mm2/s; p=0.018). There was no correlation between individual pretreatment breast tumor ADC and MR response measured after four cycles of NACT (p=0.816) or prior to surgery (p=0.620). Conclusion. Pretreatment tumor ADC does not predict treatment response for patients with LABC undergoing NACT. Furthermore, ADC increase observed mid-way in the course of NACT does not correlate with tumor volume changes.

  2. 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.

  3. Magnetic resonance imaging of the bone marrow

    International Nuclear Information System (INIS)

    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.

  4. 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.

  5. Cerebellar hemangioblastoma: magnetic resonance findings

    International Nuclear Information System (INIS)

    To characterize the results of magnetic resonance imaging in cerebellar hemangioblastoma. This retrospective study deals with seven cases of histologically-confirmed cerebellar hemangioblastoma after surgery. Another patient, diagnosed as having Von Hippel-Lindau disease, also developed this lesions, but the finding was not histologically confirmed. In all, there were 2 women and 6 men. Three of these patients presented Von Hippel-Lindaus disease. All were studied on a 0.5 T imager with T1, T2 and PD-weighted spin-echo axial planes; T1-weighted sequences were repeated after intravenous gadolinium administration. According to their aspects, the lesions were divided into three groups as follows: cyst containing a mural nodule (n=3)solid tumor (n=3) and cavitated tumor (n=1). In one patient, the lesion was initially solid and was found to present cavitation two years later. Abnormal vascularization was observed in all the tumors except for two small solid tumors, and the findings were not clear in one of the cysts containing a mural nodule. In the differential diagnosis it may be difficult to rule out other tumors, such as cystic astrocytoma. However, magnetic resonance imaging, together with the clinical data, is of diagnostic value in the three morphological types of cerebellar hemangioblastoma. (Author) 15 refs

  6. 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.)

  7. 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.

  8. 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.

  9. Object-oriented magnetic resonance classes and objects, calculations and computations

    CERN Document Server

    Mehring, Michael

    2001-01-01

    This book presents, for the first time, a unified treatment of the quantum mechanisms of magnetic resonance, including both nuclear magnetic resonance (NMR) and electron spin resonance (ESR). Magnetic resonance is perhaps the most advanced type of spectroscopy and it is applied in biology, chemistry, physics, material science, and medicine. If applied in conjunction with spectroscopy, the imaging version of magnetic resonance has no counterpart in any type of experimental technique. The authors present explanations and applications from fundamental to advanced levels. Additionally, the

  10. Magnetic Resonance Imaging of Electrolysis.

    Science.gov (United States)

    Meir, Arie; Hjouj, Mohammad; Rubinsky, Liel; Rubinsky, Boris

    2015-02-01

    This study explores the hypothesis that Magnetic Resonance Imaging (MRI) can image the process of electrolysis by detecting pH fronts. The study has relevance to real time control of cell ablation with electrolysis. To investigate the hypothesis we compare the following MR imaging sequences: T1 weighted, T2 weighted and Proton Density (PD), with optical images acquired using pH-sensitive dyes embedded in a physiological saline agar solution phantom treated with electrolysis and discrete measurements with a pH microprobe. We further demonstrate the biological relevance of our work using a bacterial E. Coli model, grown on the phantom. The results demonstrate the ability of MRI to image electrolysis produced pH changes in a physiological saline phantom and show that these changes correlate with cell death in the E. Coli model grown on the phantom. The results are promising and invite further experimental research.

  11. 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.

  12. Synovial pathology: Magnetic resonance study

    International Nuclear Information System (INIS)

    The synovial membrane lines the inner surface of the entire joint capsule of the so-called synovial, or diarthrosis, joints. It also constitutes the lining synovial bursa and tendon sheaths. It is lubricated at all these sites by the synovial fluid secreted by the membrane itself. The identification of this structure is bases on the correct knowledge of its anatomical locations. Synovial membrane pathology includes lesions produced by tumors, inflammation, degeneration and trauma. In this report, we classify them as benign (cysts, chondromatosis, pigmented villonodular synovitis, inflammatory synovitis and hemangioma) or malignant (synovial sarcoma and hemangiosarcoma). Magnetic resonance (MR) constitutes a useful and reliable method for diagnosis synovial lesions, providing a means of determining their origin and identifying distinctive features of some types. We present our experience in 12 cases of synovial pathology studied by MR over the past year, all of which were confirmed by histopathological study. 13 refs

  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. Fetal abdominal magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Brugger, Peter C. [Center of Anatomy and Cell Biology, Integrative Morphology Group, Medical University of Vienna, Waehringerstrasse 13, 1090 Vienna (Austria)]. E-mail: peter.brugger@meduniwien.ac.at; Prayer, Daniela [Department of Radiology, Medical University of Vienna, Waehringerguertel 18-20, 1090 Vienna (Austria)

    2006-02-15

    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.

  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. 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 ...

  17. 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

  18. Pituitary tumors: Diagnosis by magnetic resonance imaging

    International Nuclear Information System (INIS)

    This paper presents a survey of the current status of the diagnosis of pituitary tumors by means of magnetic resonance imaging. It focuses on the clinical and practical aspects. The recommended procedure and the sequences and slice orientations for magnetic resonance imaging of the pituitary gland are presented, and the features that are essential for the diagnosis of pituitary tumors are discussed. (orig.)

  19. Magnetic resonance force microscopy: recent results

    International Nuclear Information System (INIS)

    Force detection of magnetic resonance has been demonstrated experimentally and used for imaging in EPR. This paper will review the basic principles of Magnetic Resonance Force Microscopy (MRFM) and will report some recent results in NMR imaging and the operation of a low-temperature MRFM. (author). 31 refs., 14 figs

  20. 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....

  1. 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....

  2. 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.…

  3. 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

  4. Treatment of Locally Advanced Vaginal Cancer With Radiochemotherapy and Magnetic Resonance Image-Guided Adaptive Brachytherapy: Dose–Volume Parameters and First Clinical Results

    International Nuclear Information System (INIS)

    Purpose: To investigate the clinical feasibility of magnetic resonance image-guided adaptive brachytherapy (IGABT) for patients with locally advanced vaginal cancer and to report treatment outcomes. Methods and Materials: Thirteen patients with vaginal cancer were treated with external beam radiotherapy (45–50.4 Gy) plus IGABT with or without chemotherapy. Distribution of International Federation of Gynecology and Obstetrics stages among patients were as follows: 4 patients had Stage II cancer, 5 patients had Stage III cancer, and 4 patients had Stage IV cancer. The concept of IGABT as developed for cervix cancer was transferred and adapted for vaginal cancer, with corresponding treatment planning and reporting. Doses were converted to the equivalent dose in 2 Gy, applying the linear quadratic model (α/β = 10 Gy for tumor; α/β = 3 for organs at risk). Endpoints studied were gross tumor volume (GTV), dose-volume parameters for high-risk clinical target volume (HRCTV), and organs at risk, local control (LC), adverse side effects, and survival. Results: The mean GTV (± 1 standard deviation) at diagnosis was 45.3 (±30) cm3, and the mean GTV at brachytherapy was 10 (±14) cm3. The mean D90 for the HRCTV was 86 (±13) Gy. The mean D2cc for bladder, urethra, rectum, and sigmoid colon were 80 (±20) Gy, 76 (±16) Gy, 70 (±9) Gy, and 60 (±9) Gy, respectively. After a median follow-up of 43 months (range, 19–87 months), one local recurrence and two distant metastases cases were observed. Actuarial LC and overall survival rates at 3 years were 92% and 85%. One patient with Stage IVA and 1 patient with Stage III disease experienced fistulas (one vesicovaginal, one rectovaginal), and 1 patient developed periurethral necrosis. Conclusions: The concept of IGABT, originally developed for treating cervix cancer, appears to be applicable to vaginal cancer treatment with only minor adaptations. Dose-volume parameters for HRCTV and organs at risk are in a comparable range

  5. Voxelwise comparison of perfusion parameters estimated using dynamic contrast enhanced (DCE) computed tomography and DCE-magnetic resonance imaging in locally advanced cervical cancer

    International Nuclear Information System (INIS)

    Purpose: Dynamic contrast enhanced (DCE) imaging has gained interest as an imaging modality for assessment of tumor characteristics and response to cancer treatment. However, for DCE-magnetic resonance imaging (MRI) tissue contrast enhancement may vary depending on imaging sequence and temporal resolution. The aim of this study is to compare DCE-MRI to DCE-computed tomography (DCE-CT) as the gold standard. Material and methods: Thirteen patients with advanced cervical cancer were scanned once prior to chemo-radiation and during chemo-radiation with DCE-CT and -MRI in immediate succession. A total of 22 paired DCE-CT and -MRI scans were acquired for comparison. Kinetic modeling using the extended Tofts model was applied to both image series. Furthermore the similarity of the spatial distribution was evaluated using a G analysis. The correlation between the two imaging techniques was evaluated using Pe arson's correlation and the parameter means were compared using a Student's t-test (p trans (r = 0.9), flux rate constant kep (r = 0.77), extracellular volume fraction ve (r = 0.58) and blood plasma volume fraction vp (r = 0.83). All quantitative parameters were found to be significantly different as estimated by DCE-CT and -MRI. The G analysis in normalized maps revealed that 45 % of the voxels failed to find a voxel with the corresponding value allowing for an uncertainty of 3 mm in position and 3 % in value (G3,3). By reducing the criteria, the G-failure rates were: G3,5 (37 % failure), G3,10 (26% failure) and at G3,15 (19 % failure). Conclusion: Good to excellent correlations but significant bias was found between DCE-CT and -MRI. Both the Pearson's correlation and the G analysis proved that the spatial information was similar when analyzing the two sets of DCE data using the extended Tofts model. Improvement of input function sampling is needed to improve kinetic quantification using DCE-MRI

  6. Treatment of Locally Advanced Vaginal Cancer With Radiochemotherapy and Magnetic Resonance Image-Guided Adaptive Brachytherapy: Dose-Volume Parameters and First Clinical Results

    Energy Technology Data Exchange (ETDEWEB)

    Dimopoulos, Johannes C.A. [Department of Radiation Oncology, Metropolitan Hospital, Athens (Greece); Schmid, Maximilian P., E-mail: maximilian.schmid@akhwien.at [Department of Radiotherapy, Medical University of Vienna, Vienna (Austria); Fidarova, Elena; Berger, Daniel; Kirisits, Christian; Poetter, Richard [Department of Radiotherapy, Medical University of Vienna, Vienna (Austria)

    2012-04-01

    Purpose: To investigate the clinical feasibility of magnetic resonance image-guided adaptive brachytherapy (IGABT) for patients with locally advanced vaginal cancer and to report treatment outcomes. Methods and Materials: Thirteen patients with vaginal cancer were treated with external beam radiotherapy (45-50.4 Gy) plus IGABT with or without chemotherapy. Distribution of International Federation of Gynecology and Obstetrics stages among patients were as follows: 4 patients had Stage II cancer, 5 patients had Stage III cancer, and 4 patients had Stage IV cancer. The concept of IGABT as developed for cervix cancer was transferred and adapted for vaginal cancer, with corresponding treatment planning and reporting. Doses were converted to the equivalent dose in 2 Gy, applying the linear quadratic model ({alpha}/{beta} = 10 Gy for tumor; {alpha}/{beta} = 3 for organs at risk). Endpoints studied were gross tumor volume (GTV), dose-volume parameters for high-risk clinical target volume (HRCTV), and organs at risk, local control (LC), adverse side effects, and survival. Results: The mean GTV ({+-} 1 standard deviation) at diagnosis was 45.3 ({+-}30) cm{sup 3}, and the mean GTV at brachytherapy was 10 ({+-}14) cm{sup 3}. The mean D90 for the HRCTV was 86 ({+-}13) Gy. The mean D2cc for bladder, urethra, rectum, and sigmoid colon were 80 ({+-}20) Gy, 76 ({+-}16) Gy, 70 ({+-}9) Gy, and 60 ({+-}9) Gy, respectively. After a median follow-up of 43 months (range, 19-87 months), one local recurrence and two distant metastases cases were observed. Actuarial LC and overall survival rates at 3 years were 92% and 85%. One patient with Stage IVA and 1 patient with Stage III disease experienced fistulas (one vesicovaginal, one rectovaginal), and 1 patient developed periurethral necrosis. Conclusions: The concept of IGABT, originally developed for treating cervix cancer, appears to be applicable to vaginal cancer treatment with only minor adaptations. Dose-volume parameters for HRCTV and

  7. 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.

  8. Magnetic Resonance of the Knee

    International Nuclear Information System (INIS)

    Magnetic Resonance Imaging (MRI) has been applied to muscoloskeletal pathoanatomy and has proved to be useful in the detection and characterization of knees and 8 normal knees were examined. The images were obtained in the Diagnostic Centre RMRC of Naples on a 0.5 T superconductive magnetic system, using a surface coil and a spin-echo pulse sequence (SE 600/28 ms). The examined limb was immobilized and bent at 8-10 grade, extrarotated for the examination of the anterior cruciate ligament (ACL) only. Images were obtained on a 256x256 matrix and had a 2 or 4-mm thickness. MRI cleary showed all the anatomical structures. The anterior and posterior cruciate ligaments (ACL and PAL) and tha patellar ligament were shown by sagittal SE images through the intercondylar notch; the tibial and fibular collateral ligaments (TCL and FCL) were evaluated on coronal SE images; the articular capsula and menisci on axial transverse SE images. Objective criteria for ACL and PCL tears were: lack of continuity of the signal and change in signal intensity; in meniscal pathology, menisci with small linear regions of increased signal or with grossly truncated shape were interpreted as tears. Preliminary results of this study indicate that MRI together with clinical evaluation may be an useful non-invasive procedure in the assessment of acute injuries of the knee

  9. Magnetic Microparticle Aggregation For Viscosity Determination By Magnetic Resonance

    OpenAIRE

    Hong, Rui; Cima, Michael J; Weissleder, Ralph; Josephson, Lee

    2008-01-01

    Micron-sized magnetic particles were induced to aggregate when placed in homogeneous magnetic fields, like those of magnetic resonance (MR) imagers and relaxometers, and then spontaneously returned to their dispersed state when removed from the field. Associated with the aggregation and dispersion of the magnetic particles were time dependent increases and decreases in the spin-spin relaxation time (T2) of the water. Magnetic nanoparticles, with far smaller magnetic moments per particle, did ...

  10. Nuclear Magnetic Resonance imaging; Resonance magnetique nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Thibierge, M.; Sevestre, L.; Slupecki, P. [Centre Hospitalier de Charleville-Mezieres, 08 (France)

    1998-06-01

    After many years of low profile business in the USA, MRI is back. Improvements are focused on high field magnets and on low field magnets. The former, are dedicated to high quality imaging. The new scanners are more and more efficient because of the spreading use of real time imaging. They can do now, procedures that just could not be imagined some years ago. Vascular imaging is done routinely. Abdominal imaging in apnea of EPI, perfusion and diffusion imaging, and, last not least, all the field of functional imaging are on the verge of coming out. The new magnets unveiled in 1997 are lighter, smaller, more, user friendly, less impressive for patients subject to claustrophobia. They also need less helium to operate and less space to be sited. The latter, are dedicated to interventional procedures. The new magnets are wide opened and a lot of companies show off. Though Picker unveiled a new light superconductive 0.5 Tesla magnet, it seems that this kind of machines are about to disappear. No significant progress was noticed in the field of dedicated MRI devices. Some features can be highlighted: the new Siemens short bore and its table integrates the Panoramic Array Coil Concept. It will allow simultaneous scanning with up to four coils; the excellent homogeneity of the new Picker magnet that will allow spectroscopy at 1 Tesla; the twin gradients of the Elscint Prisma that will open the field of microscopy MRI; the Philips `floppy gradients` that could speed up 4 or 6 times, the time needed for imaging; some new sequences sensitive to temperature are studied as WIP; a lot of work is achieved on 3 or 4 Tesla scanners etc. (author)

  11. 5.4 Magnetic Resonance Imaging, Diagnostic Ultrasound

    Science.gov (United States)

    Bernhardt, J. H.

    This document is part of Subvolume A 'Fundamentals and Data in Radiobiology, Radiation Biophysics, Dosimetry and Medical Radiological Protection' of Volume 7 'Medical Radiological Physics' of Landolt-Börnstein - Group VIII 'Advanced Materials and Technologies'. It contains the Section '5.4 Magnetic Resonance Imaging, Diagnostic Ultrasound' of the Chapter '5 Medical Radiological Protection' with the contents:

  12. Magnetic resonance angiography: the state of the art

    International Nuclear Information System (INIS)

    Three-dimensional contrast magnetic resonance angiography has rapidly advanced over recent years. It is now a highly accurate and safe method of diagnosing vascular abnormalities of the thoracic, abdominal and peripheral vessels. We describe techniques for the examination of the thoracic and abdominal aorta, the renal arteries and the lower limb vessels together with strategies to improve their diagnostic accuracy. (orig.)

  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. 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.

  15. Magnetic resonance imaging of the small bowel

    Energy Technology Data Exchange (ETDEWEB)

    Deeab, Dhafer A., E-mail: dhafer_ahmed@yahoo.co [Department of Radiology, St Mary' s Campus, Imperial College NHS Trust, London (United Kingdom); Dick, Elizabeth; Sergot, Antoni A.; Sundblon, Lauren; Gedroyc, Wady [Department of Radiology, St Mary' s Campus, Imperial College NHS Trust, London (United Kingdom)

    2011-02-15

    Magnetic Resonance Imaging of the Small Bowel (MR Enterography, or MRE) is becoming increasingly popular as the first imaging modality for the diagnosis and follow-up of small bowel diseases. The inherent advantages of MRI, including excellent soft tissue contrast, multiplanar capability and lack of ionising radiation are well known. In addition, the use of luminal contrast agents in MRE has the added advantage of demonstrating the lumen and the wall directly, something not possible to achieve with conventional small bowel barium follow-through imaging. This review will highlight recent technical advances to this low cost, simple technique which is easily achievable in all hospitals. It will also review normal and abnormal radiological findings and highlight the value of this technique to both the clinician and patient alike in the investigation of small bowel disease.

  16. Magnetic resonance imaging of the small bowel

    International Nuclear Information System (INIS)

    Magnetic Resonance Imaging of the Small Bowel (MR Enterography, or MRE) is becoming increasingly popular as the first imaging modality for the diagnosis and follow-up of small bowel diseases. The inherent advantages of MRI, including excellent soft tissue contrast, multiplanar capability and lack of ionising radiation are well known. In addition, the use of luminal contrast agents in MRE has the added advantage of demonstrating the lumen and the wall directly, something not possible to achieve with conventional small bowel barium follow-through imaging. This review will highlight recent technical advances to this low cost, simple technique which is easily achievable in all hospitals. It will also review normal and abnormal radiological findings and highlight the value of this technique to both the clinician and patient alike in the investigation of small bowel disease.

  17. 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.

  18. 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)

  19. Artifacts in Magnetic Resonance Imaging

    International Nuclear Information System (INIS)

    Artifacts in magnetic resonance imaging and foreign bodies within the patient’s body may be confused with a pathology or may reduce the quality of examinations. Radiologists are frequently not informed about the medical history of patients and face postoperative/other images they are not familiar with. A gallery of such images was presented in this manuscript. A truncation artifact in the spinal cord could be misinterpreted as a syrinx. Motion artifacts caused by breathing, cardiac movement, CSF pulsation/blood flow create a ghost artifact which can be reduced by patient immobilization, or cardiac/respiratory gating. Aliasing artifacts can be eliminated by increasing the field of view. An artificially hyperintense signal on FLAIR images can result from magnetic susceptibility artifacts, CSF/vascular pulsation, motion, but can also be found in patients undergoing MRI examinations while receiving supplemental oxygen. Metallic and other foreign bodies which may be found on and in patients’ bodies are the main group of artifacts and these are the focus of this study: e.g. make-up, tattoos, hairbands, clothes, endovascular embolization, prostheses, surgical clips, intraorbital and other medical implants, etc. Knowledge of different types of artifacts and their origin, and of possible foreign bodies is necessary to eliminate them or to reduce their negative influence on MR images by adjusting acquisition parameters. It is also necessary to take them into consideration when interpreting the images. Some proposals of reducing artifacts have been mentioned. Describing in detail the procedures to avoid or limit the artifacts would go beyond the scope of this paper but technical ways to reduce them can be found in the cited literature

  20. 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...

  1. 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)

  2. Presurgical functional magnetic resonance imaging

    International Nuclear Information System (INIS)

    Functional magnetic resonance imaging (fMRI) is an important and novel neuroimaging modality for patients with brain tumors. By non-invasive measurement, localization and lateralization of brain activiation, most importantly of motor and speech function, fMRI facilitates the selection of the most appropriate and sparing treatment and function-preserving surgery. Prerequisites for the diagnostic use of fMRI are the application of dedicated clinical imaging protocols and standardization of the respective imaging procedures. The combination with diffusion tensor imaging (DTI) also enables tracking and visualization of important fiber bundles such as the pyramidal tract and the arcuate fascicle. These multimodal MR data can be implemented in computer systems for functional neuronavigation or radiation treatment. The practicability, accuracy and reliability of presurgical fMRI have been validated by large numbers of published data. However, fMRI cannot be considered as a fully established modality of diagnostic neuroimaging due to the lack of guidelines of the responsible medical associations as well as the lack of medical certification of important hardware and software components. This article reviews the current research in the field and provides practical information relevant for presurgical fMRI. (orig.)

  3. 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.)

  4. 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.

  5. 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.

  6. Implementation of NMR pulse sequences for Magnetic Resonance Force Microscopy

    Science.gov (United States)

    Moores, Bradley; Eichler, Alexander; Degen, Christian

    2014-03-01

    Magnetic resonance force microscopy (MRFM) is a scanning microscopy technique that allows measuring nuclear spin densities with a resolution of a few nanometers. Ongoing efforts are aiming at improving this resolution, which might ultimately facilitate non-destructive 3D scans of complex molecules or solid state systems with atomic resolution. Here, we review our current efforts to utilize in an MRFM experiment pulsing techniques borrowed from the nuclear magnetic resonance community. The use of advanced pulsing schemes may improve signal-to-noise ratio, imaging resolution, and allow the investigation of novel phenomena.

  7. 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

  8. 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, ...

  9. 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.

  10. Magnetic resonance imaging for uterus leiomyoma diagnosis

    International Nuclear Information System (INIS)

    The possibilities of a new technique, magnetic resonance imaging (MRI) in leiomyoma diagnosis was studied. MRI has clear advantages to differentiate adenomyosis from lysosomes and to reveal combination of these processes, which can considerably influence the tactics of the treatment

  11. 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 ...

  12. Chronic liver disease: evaluation by magnetic resonance

    International Nuclear Information System (INIS)

    Magnetic resonance (MR) imaging distinguished hepatitis from fatty liver and cirrhosis in a woman with a history of alcohol abuse. Anatomic and physiologic manifestations of portal hypertension were also demonstrated by MR

  13. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

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

  14. Biliary Ascariasis on Magnetic Resonance Cholangiopancreatography

    OpenAIRE

    Hashmi, Mohammad A; Jevan K De

    2009-01-01

    A 17-year-old girl presented with features of biliary obstruction. Magnetic resonance cholangi-pancreatography revealed typical linear signals in common bile duct, which appears like Ascaris lumbricoides. The diagnosis was confirmed by endoscopic removal of the worm.

  15. 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.

  16. 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 ...

  17. 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

  18. Concepts and indications of abdominal magnetic resonance

    International Nuclear Information System (INIS)

    A literature review and conceptualization was performed of the main indications of magnetic resonance studies of the abdomen and the characteristic findings for each sequence, according to organ and pathology. The radiologist has had in mind main indications for magnetic resonance studies of the abdomen, with the purpose to guide the clinician in the choice of imaging modality that works best for the patient at diagnosis

  19. 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...

  20. 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...

  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. Cat scratch disease: magnetic resonance imaging findings

    International Nuclear Information System (INIS)

    Cat scratch disease is an infectious lymphadenitis frequently occurring in children and adolescents. We present the magnetic resonance imaging findings of two patients with this disease. In both cases, lymphadenopathy was characterized by extensive stranding of the surrounding soft tissues, consistent with the inflammatory nature of this condition. Magnetic resonance imaging can be diagnostic and may obviate the need for invasive means of evaluation in patients suspected of having cat scratch disease. (orig.)

  3. Proton magnetic resonance spectroscopy in depression

    OpenAIRE

    Naren P Rao; Venkatasubramanian, Ganesan; Bangalore N Gangadhar

    2011-01-01

    Magnetic Resonance Spectroscopy (MRS) is a unique technique that can directly assess the concentration of various biochemical metabolites in the brain. Thus, it is used in the study of molecular pathophysiology of different neuropsychiatric disorders, such as, the major depressive disorder and has been an area of active research. We conducted a computer-based literature search using the Pubmed database with ‘magnetic resonance spectroscopy’, ‘MRS’, ‘depression’, and ‘major depressive disorder...

  4. Magnetic resonance urography in children

    International Nuclear Information System (INIS)

    The imaging methods play an important role in the diagnosing of the urinary tract diseases in children. The magnetic resonance urography (MRU) aids the morphological and functional assessment of the urinary tract as well as the increase of the accuracy of the diagnosing process. Objective: The aim of the study is to assess the capabilities of the MRU for the diagnosing of the urogenital tract in children. Material and methods: In 30 children, age between 20 days and 14 years, suspected for urinary tract pathology MRU is performed. The technique includes a native and contrast examination of the abdomen and the pelvis. The duration, depending on the pathology, is between 20 and 30 min. The axial scans and the 3-dimensional reconstructed images have been processed at different reconstruction angle. The findings have been compared to the other imaging methods applied and the postoperative results. Results: The MRU has allowed to diagnose different types of urogenital diseases in children - 3 with double pyelo-calyx system, 12 with obstructed mega ureter, 5 with obstruction of the pyelo-urinary segment, 5 with accompanying parenchyma anomalies, 6 with renal calculi, 5 with tumors, 1 with extrarenal tumor formation, 3 with bladder anomalies and 1 with kidney transplantation. Most of the children have combined pathology. Conclusions: MRU shows significant advantages in a number of pathological conditions as urinary tract obstruction, renal tumors, transplanted kidney and some congenital anomalies. The technique is safe, non-invasive and relatively fast for children examinations. These features of MRU presents a reason to assume that it will replace a number of conventional radiography techniques, giving more precise diagnostic information

  5. Complex Response Function of Magnetic Resonance Spectrometers

    OpenAIRE

    Annino, G.; Cassettari, M.; Fittipaldi, M.; M. Martinelli

    2002-01-01

    A vectorial analysis of magnetic resonance spectrometers, based on traveling wave resonators and including the reference arm and the automatic control of frequency, has been developed. The proposed model, valid also for stationary wave resonators, gives the response function of the spectrometer for any working condition, including scalar detectors with arbitrary response law and arbitrary excitation frequency. The purely dispersive and purely absorptive linear responses are discussed in detai...

  6. 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....

  7. Nanoscale magnetic resonance imaging: Progress and challenges

    International Nuclear Information System (INIS)

    Magnetic resonance imaging (MRI), based on the sensitive detection of nuclear spins, enables three dimensional imaging without radiation damage. Conventional MRI techniques achieve spatial resolution that is at best a few micrometers due to sensitivity limitations of conventional inductive detection. The advent of ultrasensitive nanoscale magnetic sensing opens the possibility of extending MRI to the nanometer scale. If this can be pushed far enough, one can envision taking 3D images of individual biomolecules and, perhaps, even solving molecular structures of proteins. In this talk we will discuss issues related to nanoscale magnetic resonance imaging, especially its implementation using magnetic resonance force microscopy (MRFM). MRFM is based on the detection of ultrasmall (attonewton) magnetic forces. While 3D spatial resolution below 5 nm has been demonstrated, further progress depends on overcoming poorly understood near-surface force noise effects. We also consider the future possibility of using NV centers in diamond for detection of nanoMRI.

  8. 磁共振成像造影剂的研究进展%Advances in the contrast agents for magnetic resonance imaging

    Institute of Scientific and Technical Information of China (English)

    张放; 沙炎

    2014-01-01

    Magnetic resonance imaging has become an important mean for clinical diagnosis, and the contrast agent is one of the important parts. This paper reviews the principle and classiifcation of contrast agents, as well as the current progress in the paramagnetic and superparamagnetic contrast agents.%磁共振成像已成为临床医学诊断的重要手段,造影剂是其中重要组成部分。本文简要介绍磁共振成像造影剂的原理、分类以及当前顺磁性和超顺磁性造影剂的研究进展。

  9. 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.

  10. 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, ...

  11. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... of the head uses a powerful magnetic field, radio waves and a computer to produce detailed pictures ... medical conditions. MRI uses a powerful magnetic field, radio frequency pulses and a computer to produce detailed ...

  12. 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.

  13. 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.

  14. Low-temperature magnetic resonance force microscopy

    Science.gov (United States)

    Wago, Koichi

    Magnetic resonance force microscopy (MRFM) is a technique whose goal is to combine the three-dimensional, chemically specific imaging capability of magnetic resonance imaging with the atomic-scale spatial resolution of scanning force microscopy. MRFM relies on the detection of small oscillatory magnetic forces between spins in the sample and a magnetic tip, using a micromechanical cantilever. The force resolution is a key issue for successfully operating MRFM experiments. Operating at low temperature improves the force resolution because of the reduced thermal energy and increased mechanical Q of the cantilever. The spin polarization is also enhanced at low temperature, leading to the improved magnetic resonance sensitivity for ensemble spin samples. A low-temperature magnetic resonance force detection apparatus was built and used to demonstrate a force resolution of 8×10sp{-17}\\ N/sqrt{Hz} at 6 K with a commercial single-crystal silicon cantilever. Both nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) were detected in micron-size samples. Force-detection technique was also applied to a wide range of magnetic resonance measurements, including inversion recovery, nutation, and spin echoes. Force-detected EPR spectra of phosphorus-doped silicon revealed hyperfine splitting, illustrating the possibility of using the MRFM technique for spectroscopic purposes. An improved low-temperature magnetic resonance force microscope was also built, incorporating a magnetic tip mounted directly on the cantilever. This allows a much wider variety of samples to be investigated and greatly improves the convenience of the technique. Using the improved microscope, three-dimensional EPR imaging of diphenylpicrylhydrazil (DPPH) particles was accomplished by scanning the sample in two dimensions while stepping an external field. The EPR force map showed a broad response reflecting the size and shape of the sample, allowing a three-dimensional real

  15. 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.

  16. Embroidered Coils for Magnetic Resonance Sensors

    Directory of Open Access Journals (Sweden)

    Michael I. Newton

    2013-04-01

    Full Text Available Magnetic resonance imaging is a widely used technique for medical and materials imaging. Even though the objects being imaged are often irregularly shaped, suitable coils permitting the measurement of the radio-frequency signal in these systems are usually made of solid copper. One problem often encountered is how to ensure the coils are both in close proximity and conformal to the object being imaged. Whilst embroidered conductive threads have previously been used as antennae in mobile telecommunications applications, they have not previously been reported for use within magnetic resonance. In this paper we show that an embroidered single loop coil can be used in a commercial unilateral nuclear magnetic resonance system as an alternative to a solid copper. Data is presented showing the determination of both longitudinal (T1 and effective transverse (T2eff relaxation times for a flat fabric coil and the same coil conformed to an 8 cm diameter cylinder. We thereby demonstrate the principles required for the wider use of fabric based conformal coils within nuclear magnetic resonance and magnetic resonance imaging.

  17. Planar Magnetic Metamaterial Slabs for Magnetic Resonance Imaging Applications

    Science.gov (United States)

    Li, Chun-Lai; Guo, Jie; Zhang, Peng; Yu, Quan-Qiang; Ma, Wei-Tao; Miao, Xi-Gen; Zhao, Zhi-Ya; Luan, Lin

    2014-07-01

    A type of planar magnetic metamaterial is proposed with a square winding microstructure as a superlens for magnetic resonance imaging (MRI) applications. A direct magnetic field mapping measurement demonstrates that the radio-frequency magnetic field passing through the superlens is increased by as high as 46.9% at the position of about 3 cm behind the superlens. The resonance frequency of the fabricated slabs is found to be in good agreement with the target frequency (63.6 MHz) for a 1.5T MRI system. MRI experiments with the magnetic superlens show that the intensity of the image and the SNR (signal-to-noise ratio) are both enhanced, implying promising MRI applications of our planar magnetic superlens.

  18. Basic principles of magnetic resonance imaging - an update

    Energy Technology Data Exchange (ETDEWEB)

    Scherzinger, A.L.; Hendee, W.R.

    1985-12-01

    Magnetic resonance (MR) imaging technology has undergone many technologic advances over the past few years. Many of these advances were stimulated by the wealth of information emerging from nuclear magnetic resonance research in the areas of new and optimal scanning methods and radio-frequency coil design. Other changes arose from the desire to improve image quality, ease siting restrictions and generally facilitate the clinical use of MR equipment. Many questions, however, remain unanswered. Perhaps the most controversial technologic question involves the optimal field strength required for imaging or spectroscopic applications or both. Other issues include safety and clinical efficacy. Technologic issues affect all aspects of MR use including the choice of equipment, examination procedure and image interpretation. Thus, an understanding of recent changes and their theoretic basis is necessary. 92 references, 10 figures, 1 table.

  19. 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.)

  20. Susceptibility effects in nuclear magnetic resonance imaging

    International Nuclear Information System (INIS)

    The properties of dephasing and the resulting relaxation of the magnetization are the basic principle on which all magnetic resonance imaging methods are based. The signal obtained from the gyrating spins is essentially determined by the properties of the considered tissue. Especially the susceptibility differences caused by magnetized materials (for example, deoxygenated blood, BOLD-effect) or magnetic nanoparticles are becoming more important for biomedical imaging. In the present work, the influence of such field inhomogeneities on the NMR-signal is analyzed. (orig.)

  1. Magnetic plasmonic Fano resonance at optical frequency.

    Science.gov (United States)

    Bao, Yanjun; Hu, Zhijian; Li, Ziwei; Zhu, Xing; Fang, Zheyu

    2015-05-13

    Plasmonic Fano resonances are typically understood and investigated assuming electrical mode hybridization. Here we demonstrate that a purely magnetic plasmon Fano resonance can be realized at optical frequency with Au split ring hexamer nanostructure excited by an azimuthally polarized incident light. Collective magnetic plasmon modes induced by the circular electric field within the hexamer and each of the split ring can be controlled and effectively hybridized by designing the size and orientation of each ring unit. With simulated results reproducing the experiment, our suggested configuration with narrow line-shape magnetic Fano resonance has significant potential applications in low-loss sensing and may serves as suitable elementary building blocks for optical metamaterials. PMID:25594885

  2. 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.

  3. Focal renal masses: magnetic resonance imaging

    International Nuclear Information System (INIS)

    Thirty patients with focal renal masses were evaluated on a .12-Tesla resistive magnetic resonance unit using partial saturation and spin echo pulse sequence. Fifteen patients had cystic lesions, nine patients had renal cell carcinoma, two had metastatic lesions, one had an angiomyolipoma, and three had focal bacterial infection. Renal cell carcinomas demonstrated areas of increased signal using a partial saturation sequence. Magnetic resonance imaging accurately detected perinephric extension and vascular invasion in all patients. Metastatic disease to the kidney was uniformly low in signal, in contrast to primary renal cell carcinoma; an angiomyolipoma demonstrated very high signal intensity. Two masses resulting from acute focal bacterial nephritis were uniformly low in signal. Magnetic resonance imaging appears to be an accurate way of detecting, identifying, and staging focal renal masses

  4. 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.

  5. 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.

  6. A Magnetic Resonance Force Microscopy Quantum Computer with Tellurium Donors in Silicon

    CERN Document Server

    Berman, G P; Tsifrinovich, V I

    2001-01-01

    We propose a magnetic resonance force microscopy (MRFM)-based nuclear spin quantum computer using tellurium impurities in silicon. This approach to quantum computing combines the well-developed silicon technology with expected advances in MRFM.

  7. 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 ...

  8. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... material called gadolinium, which is less likely to cause an allergic reaction than iodinated contrast material. Tell ... magnetic field is not harmful, but it may cause some medical devices to malfunction. Most orthopedic implants ...

  9. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... MRI uses a powerful magnetic field, radio frequency pulses and a computer to produce detailed pictures of ... sounds when the coils that generate the radiofrequency pulses are activated. Some centers provide earplugs, while others ...

  10. 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 ...

  11. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... also screened for safety in the magnetic environment. Children will be given appropriately sized earplugs or headphones ... have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media MR Angiography ( ...

  12. 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 ...

  13. 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 ...

  14. 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 ...

  15. 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 ...

  16. 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 ...

  17. 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 ...

  18. Clinical applications of nuclear magnetic resonance spectroscopy: a review

    International Nuclear Information System (INIS)

    The advantages and present limitations of the clinical applications of nuclear magnetic resonance spectroscopy are reviewed in outline, with passing references to skeletal muscular studies, in particular a group of children with advanced Duchenne dystrophy, and the applications to the study of cerebral metabolism of neonates, excised kidneys, biopsy studies of breast and axillary lymph node samples, and NMR spectroscopy performed during chemotherapy of a secondary rhabdomyosarcoma in the skin. (U.K.)

  19. Survey of inappropriate use of magnetic resonance imaging

    OpenAIRE

    Oikarinen, Heljä; Karttunen, Ari; Pääkkö, Eija; Tervonen, Osmo

    2013-01-01

    Objective There are concerns that not all costly advanced imaging is appropriate. However, studies about the appropriateness of magnetic resonance imaging (MRI) are sparse. The aim of this study was to review various MRI examinations done at a university hospital to determine whether there is inappropriate use. Methods Altogether 150 common MRIs (upper abdomen or liver, lumbar spine, knee, head and head of children performed under anaesthesia, 30 each) were reviewed consecutively. The referra...

  20. Magnetic resonance imaging in the evaluation of congestive cardiac failure

    OpenAIRE

    Rajiah, Prabhakar

    2012-01-01

    Congestive cardiac failure is the end-result of various cardiac disorders, and is a major contributor to morbidity, mortality, and financial burden throughout the world. Due to advances in the knowledge of the disease and scanner technology, magnetic resonance imaging (MRI) is playing an increasingly important role in the evaluation of cardiac failure, including in establishing diagnosis, problem solving, risk stratification, and monitoring of therapy. This review discusses and illustrates th...

  1. Bladder Wall Thickness Mapping for Magnetic Resonance Cystography

    OpenAIRE

    Zhao, Yang; Liang, Zhengrong; Zhu, Hongbin; Han, Hao; Duan, Chaijie; Yan, Zengmin; Lu, Hongbing; Gu, Xianfeng

    2013-01-01

    Clinical studies have shown the evidence that the bladder wall thickness is an effective biomarker for bladder abnormalities. The clinical optical cystoscopy, the current gold standard, cannot show the wall thickness. The use of ultrasound by experts may generate some local thickness information, but the information is limited in field-of-view and is user dependent. Recent advances in magnetic resonance (MR) imaging technologies lead MR-based virtual cystoscopy or MR cystography toward a pote...

  2. 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...... standards of clinical examination and radiography, and allow direct visualisation of both joint inflammation and structural damage. Although measuring similar pathology, each of these imaging tools has its own benefits and limitations; understanding these will help researchers and clinicians to determine...

  3. Towards quantitative magnetic resonance assessment in parenchymal liver disease

    OpenAIRE

    Stoker, J.; Beuers, U.H.W.; Nederveen, A.J.; Runge, J.H.

    2015-01-01

    In this thesis several advanced magnetic resonance (MR) techniques for quantitative measurements in parenchymal liver disease are studied. In particular, certain important hallmarks of liver disease such as steatosis, fibrosis, iron overload and inflammation are studied. Steatosis or fatty liver disease can be ascertained invasively—with biopsy—but is preferable assessed non-invasively, for example with MR techniques. This thesis shows that both MR imaging and spectroscopy are preferable over...

  4. 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.)

  5. Magnetic resonance imaging of anal cancer

    International Nuclear Information System (INIS)

    AIM: The purpose of this study was to evaluate the magnetic resonance imaging (MRI) appearances of primary and recurrent anal carcinoma, and to demonstrate the commonest patterns of local and distant disease spread. METHODS: A retrospective review was performed of 27 cases of biopsy-proven anal carcinoma, where MRI was used for primary staging (9 patients) or suspected recurrence (18 patients). Two oncological radiologists reviewed the MR images, following a standardized approach. The size, extent and signal characteristics of the anal tumour were documented. Metastatic disease spread to lymph nodes, viscera and bone was recorded. In all, 7 patients with recurrent disease underwent surgery and subsequent histological correlation was performed. RESULTS: Primary and recurrent tumours were of high signal intensity relative to skeletal muscle on T2-weighted images (T2WI), and of low to intermediate signal intensity on T1-weighted images (T1WI). Lymph node metastases were of similar signal intensity to the anal cancer. Recurrent tumours were more locally advanced than primary tumours and extended into adjacent organs and the pelvic skeleton. Recurrent lymph node disease involved perirectal, presacral and internal iliac nodes more commonly than did primary lymph node disease. CONCLUSION: MRI can be useful in the primary staging of bulky tumours or of those with a long craniocaudal extent. MR has a role in the preoperative evaluation and surgical planning of cases of recurrent disease following radiotherapy

  6. 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.

  7. 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.

  8. Pancreatitis: computed tomography and magnetic resonance imaging

    International Nuclear Information System (INIS)

    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.)

  9. Rare Infraglottic Lesions in Magnetic Resonance Imaging

    International Nuclear Information System (INIS)

    Primary pathological laryngeal lesions occur rarely in infraglottic space. Modern possibilities of diagnostic imaging of infraglottic space include computed tomography (CT) and magnetic resonance (MR). Diagnostic imaging was performed in potential lesions in this area: inflammatory process – cicatrical pemphigoid, benign neoplastic process – chondroma, malignant neoplastic – squamous cell carcinoma. The aim of the paper is to present clinical and radiographical characteristics of selected lesions located in infraglottic space in MRI examination. Three patients examined at the Department of Radiology and Diagnostic Imaging of University Hospital No. 1 in Lodz (SPZOZ USK nr 1) from 2010–2011 with a pathological mass in infraglottic space. Standard imaging protocol for MRI of the neck was used in all patients: field of 1.5 T, slice thickness 3 mm, the distance between the scans 10–20%, FOV – 3 mm, sequences: T1 (TR/TE 455/9, 7 ms, T2 (TR/TE 5300/67 ms), T1 + Gd-DTPA (contrast agent Gd-DTPA at 0.2 mmol/kg). 1. It is possible to determine characteristic signal pattern for rare lesions of the infraglottic space in MRI. 2. MRI is a valuable complementary modality for the diagnostics and differentiation of lesions in infraglottic space, the evaluation of their advancement and treatment planning

  10. Magnetic resonance imaging in peripheral lung cancer

    International Nuclear Information System (INIS)

    We evaluated the usefulness of magnetic resonance imaging (MRI) by comparison of MRI studies and pathological findings in lung cancer patients. From May 2005 to May 2006, 52 lung cancer patients underwent surgical operation in our division. Forty-five patients, each with a preoperatively recognized peripheral lung lesion underwent the MRI study. Short TI inversion recovery (STIR), high b-value diffusion-weighted imaging (DWI) with free breathing scanning and dynamic MRI studies were performed. There was no statistically significant difference between adenocarcinoma (n=35) and other carcinomas (n=10) on MRI findings. Twenty-seven adenocarcinomas (less than 30 mm in diameter) were histologically diagnosed as follows: 9 patients with bronchioloalveolar carcinoma (BAC), 12 patients with advanced BAC, and 6 non-BAC cases (adenocarcinoma without a BAC component) group. When the lesions demonstrated a strong enhancement (steep type) on dynamic studies or showed a strong signal (score 4) intensity on DWI, we judged them to be positive (indicating invasion). Sensitivity, specificity and accuracy were 94.4%, 66.6%, and 85.2%, respectively. The MRI studies permitted the acquisition of more detailed information on peripheral lung adenocarcinomas, and high b-value DWI is valuable as a supporting tool in evaluating the grade of malignancy. (author)

  11. Magnetic resonance neurography. Imaging of peripheral nerves

    International Nuclear Information System (INIS)

    Magnetic resonance neurography (MRN) is a non-invasive technique using magnetic resonance imaging (MRI) in order to diagnose peripheral nerve pathologies and their underlying etiologies. MRN is already in clinical use and is now mostly used to delineate the anatomy of nerves and to establish the continuity or discontinuity of nerves in patients with traumatic nerve injuries, as well as to monitor processes of peripheral nerve degeneration and regeneration. This article reviews established and evolving novel MRN technologies with regard to their potential to meet the requirements for non-invasive imaging of peripheral nerves in clinical settings. (orig.)

  12. 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.

  13. 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)

  14. 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

  15. Magnetic resonance neurography of the brachial plexus

    Directory of Open Access Journals (Sweden)

    Vaishali Upadhyaya

    2015-01-01

    Full Text Available Magnetic Resonance Imaging (MRI is being increasingly recognised all over the world as the imaging modality of choice for brachial plexus and peripheral nerve lesions. Recent refinements in MRI protocols have helped in imaging nerve tissue with greater clarity thereby helping in the identification, localisation and classification of nerve lesions with greater confidence than was possible till now. This article on Magnetic Resonance Neurography (MRN is based on the authors′ experience of imaging the brachial plexus and peripheral nerves using these protocols over the last several years.

  16. Complex Response Function of Magnetic Resonance Spectrometers

    CERN Document Server

    Annino, G; Fittipaldi, M; Martinelli, M

    2002-01-01

    A vectorial analysis of magnetic resonance spectrometers, based on traveling wave resonators and including the reference arm and the automatic control of frequency, has been developed. The proposed modelization, valid also for stationary wave resonators, gives the response function of the spectrometer for any working condition, including scalar detectors with arbitrary responsivity law and arbitrary excitation frequency. The purely dispersive and purely absorptive linear responses are discussed in detail for different scalar detectors. The developed approach allows to optimize the performances of the spectrometer and to obtain the intrinsic lineshape of the sample in a very broad range of working conditions. More complex setups can be modelized following the proposed scheme.

  17. 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)

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

    Science.gov (United States)

    Arima, Eiji; Naitoh, Yoshitaka; Li, Yan Jun; Yoshimura, Satoru; Saito, Hitoshi; Nomura, Hikaru; Nakatani, Ryoichi; Sugawara, Yasuhiro

    2015-03-01

    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.

  19. 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

  20. Magnetic Resonance Elastography and Other Magnetic Resonance Imaging Techniques in Chronic Liver Disease: Current Status and Future Directions

    Science.gov (United States)

    Tan, Cher Heng; Venkatesh, Sudhakar Kundapur

    2016-01-01

    Recent advances in the noninvasive imaging of chronic liver disease have led to improvements in diagnosis, particularly with magnetic resonance imaging (MRI). A comprehensive evaluation of the liver may be performed with the quantification of the degree of hepatic steatosis, liver iron concentration, and liver fibrosis. In addition, MRI of the liver may be used to identify complications of cirrhosis, including portal hypertension, ascites, and the development of hepatocellular carcinoma. In this review article, we discuss the state of the art techniques in liver MRI, namely, magnetic resonance elastography, hepatobiliary phase MRI, and liver fat and iron quantification MRI. The use of these advanced techniques in the management of chronic liver diseases, including non-alcoholic fatty liver disease, will be elaborated. PMID:27563019

  1. Proton magnetic resonance spectroscopy and perfusion magnetic resonance imaging in the evaluation of musculoskeletal tumors

    International Nuclear Information System (INIS)

    Objective: To assess the role of proton magnetic resonance spectroscopy and dynamic contrast-enhanced magnetic resonance imaging in the differentiation between malignant and benign musculoskeletal tumors. Materials And Methods: Fifty-five patients with musculoskeletal tumors (27 malignant and 28 benign) were studied. The examinations were performed in a 1.5 T magnetic resonance scanner with standard protocol, and single voxel proton magnetic resonance spectroscopy with 135 msec echo time. The dynamic contrast study was performed using T1-weighted gradient-echo sequence after intravenous gadolinium injection. Time signal intensity curves and slope values were calculated. The statistical analysis was performed with the Levene's test, followed by a Student's t-test, besides the Pearson's chi-squared and Fischer's exact tests. Results: Proton magnetic resonance spectroscopy sensitivity, specificity and accuracy were, respectively, 87.5%, 92.3% and 90.9% (p < 0.0001). Statistically significant difference was observed in the slope (%/min) between benign (mean, 27.5%/min) and malignant (mean, 110.9%/min) lesions (p < 0.0001). Conclusion: The time-intensity curve and slope values using dynamic-enhanced perfusion magnetic resonance imaging in association with the presence of choline peak demonstrated by single voxel magnetic resonance spectroscopy study are useful in the differentiation between malignant and benign musculoskeletal tumors. (author)

  2. 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...

  3. Charge-magnetic interference resonant scattering studies of ferromagnetic crystals and thin films

    International Nuclear Information System (INIS)

    The element- and site-specificity of X-ray resonant magnetic scattering (XRMS) makes it an ideal tool for furthering our understanding of complex magnetic systems. In the hard X-rays, XRMS is readily applied to most antiferromagnets where the relatively weak resonant magnetic scattering (10-2-10-6Ic) is separated in reciprocal space from the stronger, Bragg charge scattered intensity, Ic. In ferro(ferri)-magnetic materials, however, such separation does not occur and measurements of resonant magnetic scattering in the presence of strong charge scattering are quite challenging. We discuss the use of charge-magnetic interference resonant scattering for studies of ferromagnetic (FM) crystals and layered films. We review the challenges and opportunities afforded by this approach, particularly when using circularly polarized X-rays. We illustrate current capabilities at the Advanced Photon Source with studies aimed at probing site-specific magnetism in ferromagnetic crystals, and interfacial magnetism in films. (authors)

  4. Foodomics imaging by mass spectrometry and magnetic resonance.

    Science.gov (United States)

    Canela, Núria; Rodríguez, Miguel Ángel; Baiges, Isabel; Nadal, Pedro; Arola, Lluís

    2016-07-01

    This work explores the use of advanced imaging MS (IMS) and magnetic resonance imaging (MRI) techniques in food science and nutrition to evaluate food sensory characteristics, nutritional value and health benefits. Determining the chemical content and applying imaging tools to food metabolomics offer detailed information about food quality, safety, processing, storage and authenticity assessment. IMS and MRI are powerful analytical systems with an excellent capability for mapping the distribution of many molecules, and recent advances in these platforms are reviewed and discussed, showing the great potential of these techniques for small molecule-based food metabolomics research. PMID:26799681

  5. Magnetic resonance imaging in sudden deafness

    International Nuclear Information System (INIS)

    The etiology of sudden deafness can remain undetermined despite extensive investigation. This study addresses the value of magnetic resonance imaging in the analysis of sudden deafness patients.Study Design: transversal cohort.Material And Method: In a prospective study, 49 patients attended at otolaryngology emergency room of Federal University of Sao Paulo - Escola Paulista de Medicina, from April 2001 to May 2003, were submitted to magnetic resonance imaging.Results: Magnetic Resonance abnormalities were seen in 23 (46.9%) patients and revealed two tumors suggestive of meningioma, three vestibular schwannomas, thirteen microangiopathic changes of the brain and five (21.7%) pathological conditions of the labyrinth.Conclusion: Sudden deafness should be approached as a symptom common to different diseases. The presence of cerebellopontine angle tumors in 10.2% of our cases, among other treatable causes, justifies the recommendation of gadolinium-enhanced magnetic resonance use, not only to study the auditory peripheral pathway, but to study the whole auditory pathway including the brain. (author)

  6. Numerical methods in electron magnetic resonance

    International Nuclear Information System (INIS)

    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

  7. 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 reviews...

  8. Sports Health Magnetic Resonance Imaging Challenge

    OpenAIRE

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

    2010-01-01

    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.

  9. Sports Health Magnetic Resonance Imaging Challenge

    Science.gov (United States)

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

    2010-01-01

    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. PMID:23015984

  10. 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)

  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. 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

  13. 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)

  14. 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...

  15. Recent progress in magnetic resonance imaging

    International Nuclear Information System (INIS)

    Magnetic resonance imaging (MRI) has become a powerful tool in the life sciences and medical diagnosis, for which it was awarded the 2003 Nobel prize in physiology or medicine. The latest progress in MRI, including medical, brain-functional, in-vivo spectroscopic, and microscopic imaging are briefly reviewed

  16. 3D Reconstruction in Magnetic Resonance Imaging

    Czech Academy of Sciences Publication Activity Database

    Mikulka, J.; Bartušek, Karel

    2010-01-01

    Roč. 6, č. 7 (2010), s. 617-620. ISSN 1931-7360 R&D Projects: GA ČR GA102/09/0314 Institutional research plan: CEZ:AV0Z20650511 Keywords : reconstruction methods * magnetic resonance imaging Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  17. 3D Reconstruction in Magnetic Resonance Imaging

    Czech Academy of Sciences Publication Activity Database

    Mikulka, J.; Bartušek, Karel

    Cambridge : The Electromagnetics Academy, 2010, s. 1043-1046. ISBN 978-1-934142-14-1. [PIERS 2010 Cambridge. Cambridge (US), 05.07.2010-08.07.2010] R&D Projects: GA ČR GA102/09/0314 Institutional research plan: CEZ:AV0Z20650511 Keywords : 3D reconstruction * magnetic resonance imaging Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  18. Brain Magnetic Resonance Imaging in Tyrosinemia

    International Nuclear Information System (INIS)

    A 3.5-year-old girl with tyrosinemia is reported. A computed tomography scan of the abdomen revealed multiple hepatic nodules. Brain magnetic resonance imaging revealed bilateral high-signal changes confined to the globus pallidus on T2-weighted images. Globus pallidus lesions likely represented neuropathologic changes such as astocytosis, delayed myelination, and status spongiosus (myelin splitting and vacuolation)

  19. 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...

  20. 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.

  1. Texture analysis methodologies for magnetic resonance imaging

    OpenAIRE

    Materka, Andrzej

    2004-01-01

    Methods for the analysis of digital-image texture are reviewed. The functions of MaZda, a computer program for quantitative texture analysis developed within the framework of the European COST (Cooperation in the Field of Scientific and Technical Research) B11 program, are introduced. Examples of texture analysis in magnetic resonance images are discussed.

  2. 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.

  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. 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...

  5. Modelling Strategies for Functional Magnetic Resonance Imaging

    DEFF Research Database (Denmark)

    Madsen, Kristoffer Hougaard

    2009-01-01

    This thesis collects research done on several models for the analysis of functional magnetic resonance neuroimaging (fMRI) data. Several extensions for unsupervised factor analysis type decompositions including explicit delay modelling as well as handling of spatial and temporal smoothness and...

  6. Quantitative dosing by nuclear magnetic resonance

    International Nuclear Information System (INIS)

    The measurement of the absolute concentration of a heavy water reference containing approximately 99.8 per cent of D2O has been performed, by an original magnetic resonance method ('Adiabatic fast passage method') with a precision of 5.10-5 on the D2O concentration. (author)

  7. Biliary ascariasis on magnetic resonance cholangiopancreatography

    Directory of Open Access Journals (Sweden)

    Mohammad A Hashmi

    2009-01-01

    Full Text Available A 17-year-old girl presented with features of biliary obstruction. Magnetic resonance cholangi-pancreatography revealed typical linear signals in common bile duct, which appears like Ascaris lumbricoides. The diagnosis was confirmed by endoscopic removal of the worm.

  8. Magnetic resonance studies of solid polymers

    International Nuclear Information System (INIS)

    This paper is a review of the application of nuclear magnetic resonance (NMR) to solid polymers. In the first, theoretical part, the elements of the theory of NMR, which are necessary for the study of the properties of solid polymers are discussed: the moments method, nuclear relaxation and the distribution of correlation times. In the second part the experimental results are presented. (author)

  9. 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.

  10. Magnetic resonance angiography in meningovascular syphilis

    International Nuclear Information System (INIS)

    Meningovascular neurosyphilis (MN) is an unusual cause of stroke in young adults. The clinical manifestations include prodromal symptoms weeks or months before definitive stroke. The diagnosis is based on clinical findings and examination of the serum and cerebrospinal fluid. We report a case of MN with basilar artery irregularities demonstrated by magnetic resonance angiography. (orig.)

  11. 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.

  12. 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...

  13. Assessing the Early Response of Advanced Cervical Cancer to Neoadjuvant Chemotherapy Using Intravoxel Incoherent Motion Diffusion-weighted Magnetic Resonance Imaging:A Pilot Study

    Institute of Scientific and Technical Information of China (English)

    Yan-Chun Wang; Dao-Yu Hu; Xue-Mei Hu; Ya-Qi Shen; Xiao-Yan Meng; Hao Tang; Zhen Li

    2016-01-01

    Background:Diffusion-weighted imaging (DWI) with the intravoxel incoherent motion (IVIM) model has shown promising results for providing both diffusion and perfusion information in cervical cancer;however,its use to predict and monitor the efficacy of neoadjuvant chemotherapy (NACT) in cervical cancer is relatively rare.The study aimed to evaluate the use of DWI with IVIM and monoexponential models to predict and monitor the efficacy of NACT in cervical cancer.Methods:Forty-two patients with primary cervical cancer underwent magnetic resonance exams at 3 time points (pre-NACT,3 weeks after the first NACT cycle,and 3 weeks after the second NACT cycle).The response to treatment was determined according to the response evaluation criteria in solid tumors 3 weeks after the second NACT treatment,and the subjects were classified as two groups:responders and nonresponders groups.The apparent diffusion coefficient (ADC),true diffusion coefficient (D),perfusion-related pseudo-diffusion coefficient (D*),and perfusion fraction (f) values were determined.The differences in IVIM-derived variables and ADC between the different groups at the different time points were calculated using an independent samples t-test.Results:The D and ADC values were all significantly higher for the responders than for the nonresponders at all 3 time points,but no significant differences were observed in the D* and f values.An analysis of the receiver operating characteristic (ROC) curves indicated that a D value threshold <0.93 × 10-3 mm2/s and an ADC threshold <1.11 × 10-3 mm2/s could differentiate responders from nonresponders at pre-NACT time point,yielding area under the curve (AUC) of which were 0.771 and 0.806,respectively.The ROC indicated that the AUCs of D and ADC at the 3 weeks after the first NACT cycle and 3 weeks after the second NACT cycle were 0.823,0.763,and 0.787,0.794,respectively.The AUC values of D and ADC at these 3 time points were not significantly different (P =0

  14. 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)

  15. Physics of Magnetic Resonance. Chapter 14

    International Nuclear Information System (INIS)

    The discovery of nuclear magnetic resonance (NMR), a property of nuclei in a magnetic field where they are able to absorb applied radiofrequency (RF) energy and subsequently release it at a specific frequency, goes back many decades to the early 1900s. Physicist Isidor I. Rabi, fascinated by the work of Otto Stern and Walther Gerlach which demonstrated that particles have intrinsic quantum properties, delved into the magnetic properties of nuclei, and in 1938 Rabi discovered the phenomenon of NMR. Several years later, in 1946, Felix Bloch and Edward Purcell refined the methods and successfully measured the NMR signal from liquids and solids. For their discoveries, Rabi received the Nobel Prize for physics in 1944 and Bloch and Purcell in 1952. While Rabi, Bloch, Purcell and other physicists working in this field had laid the foundations, a major discovery that transformed the NMR phenomenon for imaging was not made until 1973, when Paul Lauterbur developed a method for spatially encoding the NMR signal by utilizing linear magnetic field gradients. About the same time, Peter Mansfield had also discovered a means of determining the spatial structure of solids by introducing a linear gradient across the object. The idea of applying magnetic field gradients to induce spatially varying resonance frequencies to resolve the spatial distribution of magnetization was a major milestone and the beginning of magnetic resonance imaging (MRI). For their work, Lauterbur and Mansfield were awarded the Nobel Prize for medicine in 2003. Since its discovery, MRI has quickly become one of the most important medical imaging devices available to physicians today. Unlike other imaging modalities, such as X ray and computed tomography, MRI does not involve ionizing radiation. MRI also offers superior soft tissue contrast that is not possible with other imaging modalities. Furthermore, in MRI, the desired level of image contrast among different tissues can often be precisely controlled

  16. Magnetic resonance imaging in coronary heart disease

    International Nuclear Information System (INIS)

    Modern level of cardiac magnetic resonance imaging (MRI) development already allows its routine use (with proper indications) in coronary heart disease patients for studies of heart morphology and functions, performance of stress tests for evaluation of myocardial perfusion and contractile function. Coronary MRA and some other new MR techniques are close to its wide-scale clinical application. It has been shown that cardiac MRI is a valuable tool for detection of postinfarction scars, aneurysms, pseudoaneurysms, septal defects, mural thrombi and valvular regurgitations. Due to intrinsic advantages of the method it is of special value when these pathological conditions cannot be fully confirmed or excluded with echocardiography. MRI is recognized as the best imaging method for quantification of myocardial thickness, myocardial mass, systolic myocardial thickening, chamber volumes, ejection fraction and other parameters of global and regional systolic and diastolic function. MRI is used in studies of cardiac remodeling in postinfarction patients. The most attractive areas for cardiovascular applications of MRI are assessment of myocardial perfusion and non-invasive coronary angiography. Substantial progress has been achieved in these directions. There are some other new developments in studies of coronary artery disease with MRI. High-resolution MR is used for imaging and quantification of atherosclerotic plaque composition in vivo. Intravascular MR devices suitable for performing imaging-guided balloon angioplasty are created. But before MRI will be widely accepted by the medical community as a important cardiovascular imaging modality several important problems have to be solved. Further technical advances are necessary for clinical implementation of all major diagnostic capabilities of cardiac MRI. The subjective obstacles for growth of clinical applications of cardiac MRI are lack of understanding of its possibilities and benefits both by clinicians and

  17. 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.

  18. Magnetic resonance imaging in Parkinson's disease

    International Nuclear Information System (INIS)

    The width of substantia nigra (SN) in 59 cases of idiopathic Parkinson's disease as well as 21 normal controls was analyzed by T2 weighted image (T2WI) of 1.5 Tesla high-field magnetic resonance image (MRI). All patients and controls underwent MRI with the spin-echo sequences used TR/TE: 3000/30 (short TE), and TR/TE: 3000/80 (long TE), in 5-mm-thick volumes. The width between the red nucleus and the cerebral peduncle showing low signal intensity areas was measured as that of SN and its ratio to the distance from the aqueduct to the midline of the cerebral peduncle was also measured. The calculated values of the width of SN and its ratio were analyzed by Mann-Whitney test. The significant reduction in the width of SN and its ratio in Parkinson's disease were disclosed below: the mean calculated values of the width of SN were 2.95±0.51 mm in controls, 2.68±0.99 mm in Parkinson's disase on long TE images (P<0.01), and the mean ratio of the width of SN were 13.58±4.21% in controls, 10.52±3.07% in Parkinson's disease on long TE images (P=0.0002). The narrowing of SN in Parkinson's disease was more prominent in men, and advanced cases with Yahr stage III and IV. Considering that the pars reticulata, which is normally containing iron, shows low signal intensity on long TE images, the width of pars compacta could be measured more precisely on this sequences. The evaluation of the ratio of SN in midbrain on long TE images seemed to be more sensitive than the calculated values in detecting the narrowing of SN and pars compacta in Parkinson's disease. (author)

  19. Improved evolution equations for magnetic island chains in toroidal pinch plasmas subject to externally applied resonant magnetic perturbations

    International Nuclear Information System (INIS)

    An improved set of island evolution equations is derived that incorporates the latest advances in MHD (magnetohydrodynamical) theory. These equations describe the resistive/viscous-MHD dynamics of a nonlinear magnetic island chain, embedded in a toroidal pinch plasma, in the presence of a programmable, externally applied, resonant magnetic perturbation. A number of interesting example calculations are performed using the new equations. In particular, an investigation is made of a recently discovered class of multiharmonic resonant magnetic perturbations that have the novel property that they can lock resonant island chains in a stabilizing phase

  20. 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...

  1. Magnetic resonance spectroscopy in the study of esophageal cancer

    International Nuclear Information System (INIS)

    Esophageal cancer is one of the most common reasons of human death, the prognosis is closely related to the diagnosed stages. Early esophageal cancer usually has a better prognosis, while the middle -advanced stage has a poor five-year survival rate. The early diagnosis of esophageal cancer is important. In the recent years, magnetic resonance technology develops very fast the magnetic resonance spectroscopy (MRS) can be used to study the biochemistry and physiology of tumors or tissue in vivo by detecting several trace metabolites, energy metabolism and quantitatively analysing the compounds changes. Most studies focused on specimens or secretions in vivo or m vitro experiments in the literatures. We summarized the MRS studies on esophageal cancer in this article. (authors)

  2. Soft x-ray resonant magnetic diffraction.

    OpenAIRE

    Wilkins, S. B.; Hatton, P. D.; Roper, M.D.; Prabhakaran, D.; Boothroyd, A. T.

    2003-01-01

    We have conducted the first soft x-ray diffraction experiments from a bulk single crystal, studying the bilayer manganite La22xSr12xMn2O7 with x 0:475 in which we were able to access the (002) Bragg reflection using soft x rays. The Bragg reflection displays a strong resonant enhancement at the LIII and LII manganese absorption edges. We demonstrate that the resonant enhancement of the magnetic diffraction of the (001) is extremely large, indeed so large that it exceeds that of t...

  3. 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...... 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....

  4. 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.

  5. 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

  6. 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...

  7. Magnetic resonance tomography of the penis

    International Nuclear Information System (INIS)

    The magnetic resonance tomogram visualises the corpus spongiosum, the corpora cavernosa, the fascia penis profunda, the septum and the dorsal vein of the penis. These structures can be separated from the skin and from the glans penis. Changes of shape are still the essential criteria of assessment. At present it does not seem possible to be able to differentiate between diseased and healthy area if the connective tissue structures of the penis (e.g. in induratio penis plastica) do not show any change of shape. Compared with other imaging methods, imaging on different levels offers advantages, and so does the simultaneous imaging of the structures of the penis, of its environment and of the adjacent organs. We can assume that the magnetic resonance tomogram will supply essential additional information for clinical diagnosis and practice in conditions like induratio penis plastica, intersexuality, tumours of the prostate gland, and in postoperative follow-up, for example after surgery for priapism. (orig.)

  8. Magnetic resonance imaging of tuberculous spinal infection

    International Nuclear Information System (INIS)

    The magnetic resonance imaging (MRI) characteristics of 15 cases of tuberculous (TB) spinal infection were reviewed. The commonest site was the lumbar spine (53.3%) often with three or more contiguous vertebrae involved (47%). Destruction of the vertebral body and the presence of paraspinal soft-tissue masses were noted in 73.3%. Posterior element abnormalities, which is a significant finding, were seen in 40%, a slightly lower incidence rate than in other reported series. Epidural disease (53.3%) and disc abnormalities (73%) were more frequent than was realized. The role of intravenous contrast is discussed. Intravenous gadolinium is useful because it increases diagnostic confidence by characterizing and delineating the disease process, detects reactivation in old and healed TB, helps in treatment management and may prove valuable in monitoring therapy. Magnetic resonance imaging should be considered to be the imaging modality of choice for patients with suspected tuberculous spinal infection. 17 refs., 1 tab., 8 figs

  9. Quality assurance in magnetic resonance spectroscopy system

    International Nuclear Information System (INIS)

    Nuclear Magnetic Resonance Spectroscopic clinical evaluation of metabolic changes in the human body has distinct advantages over Magnetic Resonance Imaging (MRI), CT and Nuclear Medicine, as it allows early detection of disease and monitoring of therapeutic processes through repeated procedures. To ensure reliable and reproducible results for spectroscopic examinations, the quality of MRS system should be controlled. Apart from the instrumental contribution in spectroscopic examinations, there are number of other variables such as tissue state and patient motion, severely affecting the image quality. The subject and instrumental contributions to the spectrum are closely related in MRS than in rest of medical imaging. Instrumental contribution in the quality of spectrum has been measured and presented

  10. Caroli's disease: magnetic resonance imaging features

    International Nuclear Information System (INIS)

    Our objective was to describe the main aspects of MR imaging in Caroli's disease. Magnetic resonance cholangiography with a dynamic contrast-enhanced study was performed in nine patients with Caroli's disease. Bile duct abnormalities, lithiasis, dot signs, hepatic enhancement, renal abnormalities, and evidence of portal hypertension were evaluated. Three MR imaging patterns of Caroli's disease were found. In all but two patients, MR imaging findings were sufficient to confirm the diagnosis. Moreover, MR imaging provided information about the severity, location, and extent of liver involvement. This information was useful in planning the best therapeutic strategy. Magnetic resonance cholangiography with a dynamic contrast-enhanced study is a good screening tool for Caroli's disease. Direct cholangiography should be reserved for confirming doubtful cases. (orig.)

  11. 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

  12. Antiferromagnetic resonance excitation by terahertz magnetic field resonantly enhanced with split ring resonator

    International Nuclear Information System (INIS)

    Excitation of antiferromagnetic resonance (AFMR) in a HoFeO3 crystal combined with a split ring resonator (SRR) is studied using terahertz (THz) electromagnetic pulses. The magnetic field in the vicinity of the SRR is induced by the incident THz electric field component and excites spin oscillations that correspond to the AFMR, which are directly probed by the Faraday rotation of the polarization of a near-infrared probe pulse. The good agreement of the temperature-dependent magnetization dynamics with the calculation using the two-lattice Landau-Lifshitz-Gilbert equation confirms that the AFMR is excited by the THz magnetic field, which is enhanced at the SRR resonance frequency by a factor of 20 compared to the incident magnetic field.

  13. Nuclear magnetic resonance spectrometer and method

    International Nuclear Information System (INIS)

    A nuclear magnetic resonance techniis described that allows simultaneous temperature determination and spectral acquisition. The technique employs a modification of the lock circuit of a varian xl-100 spectrometer which permits accurate measurement of the difference in resonance frequency between a primary lock nucleus and another , secondary, nucleus. The field stabilization function of the main lock circuit is not compromised. A feedback signal having a frequency equal to the frequency difference is substituted for the normal power supply in the spectrometer's existing radio frequency transmitter to modulate that transmitter. Thus, the transmitter's radio frequency signal is enhanced in a frequency corresponding to the resonance peak of the secondary nucleus. Determination of the frequency difference allows the determination of temperature without interference with the observed spectrum. The feedback character of the circuit and the presence of noise make the circuit self-activating

  14. 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...

  15. Methods for interventional magnetic resonance imaging

    OpenAIRE

    Vahala, Erkki

    2002-01-01

    This thesis has as its central aim to demonstrate, develop, discuss and promote new methods and technology for improving interventional low field magnetic resonance imaging. The work addresses problems related to accurate localization of minimally invasive surgical tools by describing novel devices and improvements to prior art techniques, such as optical tracking. In addition to instrument guidance, ablative treatment of liver tumours is discussed in connection with low field temperature mea...

  16. Modelling Strategies for Functional Magnetic Resonance Imaging

    OpenAIRE

    Madsen, Kristoffer Hougaard; Sidaros, Karam; Hansen, Lars Kai

    2009-01-01

    This thesis collects research done on several models for the analysis of functional magnetic resonance neuroimaging (fMRI) data. Several extensions for unsupervised factor analysis type decompositions including explicit delay modelling as well as handling of spatial and temporal smoothness and generalisations to higher order arrays are considered. Additionally, an application of the natural conjugate prior for supervised learning in the general linear model to efficiently incorporate prior in...

  17. 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 ...

  18. Magnetic resonance in diagnosis of ureterocele

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Humberto do; Hachul, Mauricio; Macedo Junior, Antonio [Universidade Federal de Sao Paulo (UNIFESP/EPM), SP (Brazil). Div. de Urologia]. E-mail: humbertojr1@aol.com

    2003-05-15

    Ultrasonography is the main non-invasive technique for screening of ureterocele, but presents some difficulties for its diagnosis. Other supplementary diagnostic methods have the disadvantage of being invasive or using ionizing radiation. Magnetic resonance (MR) has a high sensitivity for diagnosing urinary tract malformations in adults and children. We report one case of ureterocele in a 1-year old child with the purpose of presenting its diagnosis through MR. (author)

  19. Magnetic resonance in diagnosis of ureterocele

    International Nuclear Information System (INIS)

    Ultrasonography is the main non-invasive technique for screening of ureterocele, but presents some difficulties for its diagnosis. Other supplementary diagnostic methods have the disadvantage of being invasive or using ionizing radiation. Magnetic resonance (MR) has a high sensitivity for diagnosing urinary tract malformations in adults and children. We report one case of ureterocele in a 1-year old child with the purpose of presenting its diagnosis through MR. (author)

  20. Fundamental physics of magnetic resonance imaging.

    Science.gov (United States)

    Villafana, T

    1988-07-01

    Although similar to computerized tomography, in that cross-sectional images are produced, the physical principles underlying magnetic resonance are entirely different. The MRI process, as commonly implemented, involves the excitation of hydrogen nuclei and the analysis of how these nuclei recover to the original equilibrium steady states that they had prior to excitation. This article discusses that process, that is, preparatory alignment, RF excitation, relaxation and signal measurement, and spatial localization. PMID:3380941

  1. Nuclear magnetic resonance in Kondo lattice systems

    Science.gov (United States)

    Curro, Nicholas J.

    2016-06-01

    Nuclear magnetic resonance has emerged as a vital tool to explore the fundamental physics of Kondo lattice systems. Because nuclear spins experience two different hyperfine couplings to the itinerant conduction electrons and to the local f moments, the Knight shift can probe multiple types of spin correlations that are not accessible via other techniques. The Knight shift provides direct information about the onset of heavy electron coherence and the emergence of the heavy electron fluid.

  2. Relaxation measurements by magnetic resonance force microscopy

    International Nuclear Information System (INIS)

    The spatial resolution of magnetic resonance imaging can be greatly enhanced by replacing the coil antenna (or cavity) with a scanning force microscope. We describe how this mechanical detection can be applied to the measurement of both the transverse and longitudinal relaxation inside a micron-size volume. The measurement procedure and analysis is detailed for the case of paramagnetic and ferromagnetic spin systems. (authors)

  3. Polyorchidism: Sonographic and Magnetic Resonance Image Findings

    Energy Technology Data Exchange (ETDEWEB)

    Oner, A. Y.; Sahin, C.; Pocan, S.; Kizilkaya, E. [Gazi Univ. School of Medicine, Ankara (Turkey). Dept. of Radiology

    2005-11-01

    Polyorchidism is a rare congenital anomaly frequently associated with maldescent testis, hernia, and torsion. Reports in the literature show an increased risk of testicular malignancy in the presence of polyorchidism. This entity has characteristic sonographic features and the diagnosis is often made on the basis of sonography. Magnetic resonance imaging might also be used for the diagnosis, but is more helpful in cases associated with cryptorchism or neoplasia. A conservative approach is the treatment of choice in uncomplicated cases.

  4. Polyorchidism: Sonographic and Magnetic Resonance Image Findings

    International Nuclear Information System (INIS)

    Polyorchidism is a rare congenital anomaly frequently associated with maldescent testis, hernia, and torsion. Reports in the literature show an increased risk of testicular malignancy in the presence of polyorchidism. This entity has characteristic sonographic features and the diagnosis is often made on the basis of sonography. Magnetic resonance imaging might also be used for the diagnosis, but is more helpful in cases associated with cryptorchism or neoplasia. A conservative approach is the treatment of choice in uncomplicated cases

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. Noise and filtration in magnetic resonance imaging

    OpenAIRE

    McVeigh, E. R.; Henkelman, R.M.; Bronskill, M. J.

    1985-01-01

    Noise in two-dimensional Fourier transform magnetic resonance images has been investigated using noise power spectra and measurements of standard deviation. The measured effects of averaging, spatial filtering, temporal filtering, and sampling have been compared with theoretical calculations. The noise of unfiltered images is found to be white, as expected, and the choice of the temporal filter and sampling interval affects the noise in a manner predicted by sampling theory. The shapes of the...

  10. 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...

  11. 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...

  12. "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.

  13. 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...

  14. 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...

  15. 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.

  16. Applications of Magnetic Resonance in Model Systems: Cancer Therapeutics1

    OpenAIRE

    Evelhoch, Jeffrey L.; Gillies, Robert J; Karczmar, Gregory S.; Koutcher, Jason A; Maxwell, Ross J.; Nalcioglu, Orhan; Raghunand, Natarajan; Ronen, Sabrina M.; Ross, Brian D.; Swartz, Harold M.

    2000-01-01

    The lack of information regarding the metabolism and pathophysiology of individual tumors limits, in part, both the development of new anti-cancer therapies and the optimal implementation of currently available treatments. Magnetic resonance [MR, including magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), and electron paramagnetic resonance (EPR)] provides a powerful tool to assess many aspects of tumor metabolism and pathophysiology. Moreover, since this information ca...

  17. SQUID-detected magnetic resonance imaging in microtesla magnetic fields

    International Nuclear Information System (INIS)

    We describe studies of nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) of liquid samples at room temperature in microtesla magnetic fields. The nuclear spins are prepolarized in a strong transient field. The magnetic signals generated by the precessing spins, which range in frequency from tens of Hz to several kHz, are detected by a low-transition temperature dc SQUID (Superconducting QUantum Interference Device) coupled to an untuned, superconducting flux transformer configured as an axial gradiometer. The combination of prepolarization and frequency-independent detector sensitivity results in a high signal-to-noise ratio and high spectral resolution (∼1 Hz) even in grossly inhomogeneous magnetic fields. In the NMR experiments, the high spectral resolution enables us to detect the 10-Hz splitting of the spectrum of protons due to their scalar coupling to a 31P nucleus. Furthermore, the broadband detection scheme combined with a non-resonant field-reversal spin echo allows the simultaneous observation of signals from protons and 31P nuclei, even though their NMR resonance frequencies differ by a factor of 2.5. We extend our methodology to MRI in microtesla fields, where the high spectral resolution translates into high spatial resolution. We demonstrate two-dimensional images of a mineral oil phantom and slices of peppers, with a spatial resolution of about 1 mm. We also image an intact pepper using slice selection, again with 1-mm resolution. In further experiments we demonstrate T1-contrast imaging of a water phantom, some parts of which were doped with a paramagnetic salt to reduce the longitudinal relaxation time T1. Possible applications of this MRI technique include screening for tumors and integration with existing multichannel SQUID systems for brain imaging

  18. Electro-mechanical resonant magnetic field sensor

    International Nuclear Information System (INIS)

    We describe a new type of magnetic field sensor, which is termed as 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 f1. 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 by 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 0.001 G for an applied magnetic field of ∼1 G and a good selectivity for the magnetic field direction. The sensitivity can be easily improved by a factor of ∼10-100 by a more sensitive measurement of the elastic element motion and by having the element in vacuum to reduce the drag force

  19. Early diffusion weighted magnetic resonance imaging can predict survival in women with locally advanced cancer of the cervix treated with combined chemo-radiation

    International Nuclear Information System (INIS)

    To assess the predictive value of diffusion weighted imaging (DWI) for survival in women treated for advanced cancer of the cervix with concurrent chemo-radiotherapy. Twenty women treated for advanced cancer of the cervix were recruited and followed up for a median of 26 (range -3/mm2/s), respectively, P = 0.02. The median change in ADC 14 days after treatment commencement was significantly higher in the alive group compared to non-survivors, 0.28 and 0.14 (x 10-3/mm2/s), respectively, P = 0.02. There was no evidence of a difference between survivors and non-survivors for pretreatment baseline or post-therapy ADC values. Functional DWI early in the treatment of advanced cancer of the cervix may provide useful information in predicting survival. (orig.)

  20. Magnetic Resonance Imaging of Gel-cast Ceramic Composites

    Science.gov (United States)

    Dieckman, S. L.; Balss, K. M.; Waterfield, L. G.; Jendrzejczyk, J. A.; Raptis, A. C.

    1997-01-16

    Magnetic resonance imaging (MRI) techniques are being employed to aid in the development of advanced near-net-shape gel-cast ceramic composites. MRI is a unique nondestructive evaluation tool that provides information on both the chemical and physical properties of materials. In this effort, MRI imaging was performed to monitor the drying of porous green-state alumina - methacrylamide-N.N`-methylene bisacrylamide (MAM-MBAM) polymerized composite specimens. Studies were performed on several specimens as a function of humidity and time. The mass and shrinkage of the specimens were also monitored and correlated with the water content.

  1. Whole-body diffusion-weighted magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kwee, Thomas C. [Department of Radiology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht (Netherlands)], E-mail: thomaskwee@gmail.com; Takahara, Taro [Department of Radiology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht (Netherlands); Department of Radiology, Tokai University School of Medicine, Isehara, Kanagawa (Japan); Ochiai, Reiji [Department of Radiology, Koga Hospital 21, Kurume, Fukuoka (Japan); Katahira, Kazuhiro [Department of Radiology, Kumamoto University School of Medicine, Honjo, Kumamoto (Japan); Van Cauteren, Marc [Philips Healthcare Asia Pacific, Shinagawa, Tokyo (Japan); Imai, Yutaka [Department of Radiology, Tokai University School of Medicine, Isehara, Kanagawa (Japan); Nievelstein, Rutger A.J.; Luijten, Peter R. [Department of Radiology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht (Netherlands)

    2009-06-15

    Diffusion-weighted magnetic resonance imaging (DWI) provides information on the diffusivity of water molecules in the human body. Technological advances and the development of the concept of diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) have opened the path for routine clinical whole-body DWI. Whole-body DWI allows detection and characterization of both oncological and non-oncological lesions throughout the entire body. This article reviews the basic principles of DWI and the development of whole-body DWI, illustrates its potential clinical applications, and discusses its limitations and challenges.

  2. The magnetic resonance force microscope: A new microscopic probe of magnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Hammel, P.C.; Zhang, Z. [Los Alamos National Lab., NM (United States); Midzor, M.; Roukes, M.L. [California Inst. of Tech., Pasadena, CA (United States); Wigen, P.E. [Ohio State Univ., Columbus, OH (United States); Childress, J.R. [Univ. of Florida, Gainesville, FL (United States)

    1997-08-06

    The magnetic resonance force microscope (MRFM) marries the techniques of magnetic resonance imaging (MRI) and atomic force microscopy (AFM), to produce a three-dimensional imaging instrument with high, potentially atomic-scale, resolution. The principle of the MRFM has been successfully demonstrated in numerous experiments. By virtue of its unique capabilities the MRFM shows promise to make important contributions in fields ranging from three-dimensional materials characterization to bio-molecular structure determination. Here the authors focus on its application to the characterization and study of layered magnetic materials; the ability to illuminate the properties of buried interfaces in such materials is a particularly important goal. While sensitivity and spatial resolution are currently still far from their theoretical limits, they are nonetheless comparable to or superior to that achievable in conventional MRI. Further improvement of the MRFM will involve operation at lower temperature, application of larger field gradients, introduction of advanced mechanical resonators and improved reduction of the spurious coupling when the magnet is on the resonator.

  3. 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.)

  4. Early diffusion weighted magnetic resonance imaging can predict survival in women with locally advanced cancer of the cervix treated with combined chemo-radiation

    Energy Technology Data Exchange (ETDEWEB)

    Somoye, Gbolahan; Parkin, David [Ward 42, Aberdeen Royal Infirmary, Aberdeen (United Kingdom); Harry, Vanessa [Royal Marsden NHS Foundation Trust, London (United Kingdom); Semple, Scott [Queen' s Medical Research Institute, Centre for Cardiovascular Science, Clinical Research Imaging Centre, Edinburgh (United Kingdom); Plataniotis, George [Musgrove Park Hospital, Taunton and Somerset NHS Foundation, Taunton (United Kingdom); Scott, Neil [University of Aberdeen, Section of Population Health, Aberdeen (United Kingdom); Gilbert, Fiona J. [University of Cambridge, Radiology Department, Box 218, Cambridge (United Kingdom)

    2012-11-15

    To assess the predictive value of diffusion weighted imaging (DWI) for survival in women treated for advanced cancer of the cervix with concurrent chemo-radiotherapy. Twenty women treated for advanced cancer of the cervix were recruited and followed up for a median of 26 (range <1 to 43) months. They each had DWI performed before treatment, 2 weeks after beginning therapy (midtreatment) and at the end of treatment. Apparent diffusion coefficient (ADC) values were calculated from regions of interest (ROI). All participants were reviewed for follow-up data. ADC values were compared with mortality status (Mann-Whitney test). Time to progression and overall survival were assessed (Kaplan-Meier survival graphs). There were 14 survivors. The median midtreatment ADC was statistically significantly higher in those alive compared to the non-survivors, 1.55 and 1.36 (x 10{sup -3}/mm{sup 2}/s), respectively, P = 0.02. The median change in ADC 14 days after treatment commencement was significantly higher in the alive group compared to non-survivors, 0.28 and 0.14 (x 10{sup -3}/mm{sup 2}/s), respectively, P = 0.02. There was no evidence of a difference between survivors and non-survivors for pretreatment baseline or post-therapy ADC values. Functional DWI early in the treatment of advanced cancer of the cervix may provide useful information in predicting survival. (orig.)

  5. Magnetic resonance imaging. Handbook and atlas

    International Nuclear Information System (INIS)

    Magnetic resonance imaging (MRI) as a diagnostic imaging tool relies on the generation of magnetic fields, whereas the computerized tomography (CT) uses X-radiation. The fundamental principle of MRI is the magnetic resonance of paramagnetic atomic nuclei. These nuclei, as e.g. protons (= hydrogen nuclei), are aligned in required orientation by application of a strong magnetic field. Upon simultaneous application of an electromagnetic high-frequency field perpendicular to the axis of the basic magnetic field, and in response to periodical changing of the electromagnetic field at a given frequency, the originally aligned paramagnetic nuclei are forced into a movement similar to that of a ''whipping top''. When the resonance frequency is shut off, the nuclei return to their former, aligned positions, inducing a weak signal in a coil. The series of signals generated by multiple repetition of this process of excitation of nuclei and their return to aligned rest is used as input to a specific computer for computing the 3D image. Thus images can be generated of the target body area from different angles and in different planes by varying the magnetic fields applied. Other than with the CT method, imaging of the various selected planes with MRI must not be done consecutively but is done in one scanning run (for a set of images of about 20 planes). The signal that is received by the coil is determined by the proton density in the volume compartment scanned, and by the relaxation times T1 and T2, which are the times needed by the nuclei to return to aligned rest. The relaxation times in turn are determined by the bonding states of the molecules and thus yield the significant information describing the actual physical and chemical properties of the body tissues scanned. So MRI yields sectional or ''sliced'' images of the body region of interest, as well as information describing tissue type and properties. Today, almost exclusively protons are used for MRI, as hydrogen is a

  6. 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)

  7. Magnetic resonance force detection using a membrane resonator

    Science.gov (United States)

    Scozzaro, Nicolas; Ruchotzke, William; Belding, Amanda; Cardellino, Jeremy; Blomberg, Erick; McCullian, Brendan; Bhallamudi, Vidya; Pelekhov, Denis; Hammel, P. Chris

    Silicon nitride (Si3N4) membranes are commercially-available, versatile structures that have a variety of applications. Although most commonly used as the support structure for transmission electron microscopy (TEM) studies, membranes are also ultrasensitive high-frequency mechanical oscillators. The sensitivity stems from the high quality factor Q 106 , which has led to applications in sensitive quantum optomechanical experiments. The high sensitivity also opens the door to ultrasensitive force detection applications. We report force detection of electron spin magnetic resonance at 300 K using a Si3N4 membrane with a force sensitivity of 4 fN/√{ Hz}, and a potential low temperature sensitivity of 25 aN/√{ Hz}. Given membranes' sensitivity, robust construction, large surface area and low cost, SiN membranes can potentially serve as the central component of a compact room-temperature ESR and NMR instrument that has superior spatial resolution to conventional NMR.

  8. 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

  9. 76 FR 58281 - Magnetic Resonance Imaging Safety; Public Workshop

    Science.gov (United States)

    2011-09-20

    ... HUMAN SERVICES Food and Drug Administration Magnetic Resonance Imaging Safety; Public Workshop AGENCY... the safe use of magnetic resonance imaging (MRI) and approaches to mitigate risks. The overall goal is...: The Food and Drug Administration (FDA) is announcing a public workshop entitled: ``Magnetic...

  10. Multiparametric magnetic resonance imaging of prostate cancer

    Directory of Open Access Journals (Sweden)

    Sandeep S Hedgire

    2012-01-01

    Full Text Available In India, prostate cancer has an incidence rate of 3.9 per 100,000 men and is responsible for 9% of cancer-related mortality. It is the only malignancy that is diagnosed with an apparently blind technique, i.e., transrectal sextant biopsy. With increasing numbers of high-Tesla magnetic resonance imaging (MRI equipment being installed in India, the radiologist needs to be cognizant about endorectal MRI and multiparametric imaging for prostate cancer. In this review article, we aim to highlight the utility of multiparamteric MRI in prostate cancer. It plays a crucial role, mainly in initial staging, restaging, and post-treatment follow-up.

  11. 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.)

  12. Magnetic resonance imaging of the pediatric airway

    International Nuclear Information System (INIS)

    Evaluation of the pediatric airway is often complex and may require multiple imaging techniques and invasive procedures. We performed magnetic resonance (MR) imaging of the airway in 34 children with clinical evidence of chronic airway obstruction and compared MR findings with those obtained by surgery and/or endoscopy. MR diagnoses included vascular compression in 15 patients, primary tracheomalacic states in 12 patients, and mediastinal masses in 4 patients. Findings were normal for 3 patients. The MR findings were in agreement with the endoscopic findings in 25 to 28 cases and in agreement with the surgical findings in 21 to 21 cases. (orig./GDG)

  13. 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.

  14. Proton magnetic resonance spectroscopy in schizophrenia

    International Nuclear Information System (INIS)

    Proton magnetic resonance spectroscopy (MRS) has become an important tool to study in vivo certain biochemical aspects of brain disorders. In the last decade this technique has been applied to the in vivo investigation of pathophysiological aspects of psychiatric disorders, extending knowledge of the related brain alterations. This review will focus on providing some background to clarify technical and biochemical issues and it will describe the studies that have been performed in schizophrenia. The results will be framed in a more general context to highlight what we have learned and what remains to be understood from the application of this technique to schizophrenia

  15. 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.

  16. Functional Magnetic Resonance Imaging in Consumer Research

    DEFF Research Database (Denmark)

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

    2011-01-01

    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 o...... 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....

  17. Magnetic resonance imaging (MRI) of cerebral infarction

    International Nuclear Information System (INIS)

    Fifty-five patients with cerebral infarction were studied with magnetic resonance imaging (MRI) and correlative CT scans. MRI was more sensitive than CT for detecting cerebral infarction, and T2-weighted spin-echo (SE) pulse sequence was most sensitive for detecting cerebral infarction except for some subcortical infarction. The size of infarcted areas on MRI was larger than that on CT in 29 of 51 infarcted areas, equal in 22. The pulse sequence using long repetition time (TR) and double echo delay time (TE), such as SE (2000/30, 90), improved the detectability of cerebral infarction. (author)

  18. Magnetic resonance aspects in ulnar styloid nonunion

    International Nuclear Information System (INIS)

    Ulnar syloid process nonunion fractures are common, although isolated fractures may not be recognized and become a persistent wrist pain. Most time the fractures are asymptomatic. It is important , in symptomatic patients, the characterization of the lesion and the commitment of other structures that compose distal radio-ulnar joint for proper treatment. The classification is based on radio-ulnar joint stability. We report wrist magnetic resonance images from two patients, each one with one type of nonunion classification, which is based in anatomic findings and treatment options. (author)

  19. Magnetic resonance spectroscopy studies in migraine

    International Nuclear Information System (INIS)

    The authors describe the method of 31phosphorus 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

  20. 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.

  1. Magnetic resonance imaging of cystic ovarian tumors

    International Nuclear Information System (INIS)

    We studied 48 cases of cystic ovarian tumors by magnetic resonance imaging (MRI) with 0.15 T resistive system and examined the ability of qualitative diagnosis by means of signal intensities and caluculated T1 values. MRI supposed to discriminate among various kinds of cystic ovarian tumors in most cases, especially dermoid cysts, endometrial cysts and cystadenomas. MRI has lots of merits which other imaging methods cannot offer, though it takes a long scan time and high cost at the present time. It plays an important role in the diagnosis of cystic ovarian tumors. (author)

  2. 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.)

  3. 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).

  4. Magnetic Resonance Signal Processing in Medical Applications

    Czech Academy of Sciences Publication Activity Database

    Mikulka, J.; Gescheidtová, E.; Bartušek, Karel

    Saint Gilles: IARIA, 2012, s. 148-153. ISBN 978-1-61208-184-7. [GlobeNet 2012: ICN 2012, ICONS 2012, VisGra 2012, DBKDA 2012. Saint Gilles (RE), 29.02.2012-05.03.2012] R&D Projects: GA MŠk ED0017/01/01; GA ČR GAP102/11/0318 Institutional support: RVO:68081731 Keywords : magnetic resonance * biomedical image processing * image segmentation * level set * active countour * edge analysis * noise suppression * volumetry Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  5. Magnetic resonance images of chronic patellar tendinitis

    International Nuclear Information System (INIS)

    Chronic patellar tendinitis can be a frustrating diagnostic and therapeutic problem. This report evaluates seven tendons in five patients with chronic patellar tendinitis. The etiologies included 'jumper's knee' and Osgood-Schlatter disease. In all cases magnetic resonance images (MRI) showed thickening of the tendon. Some of the tendons had focal areas of thickening which helped establish the etiology. All cases had intratendinous areas of increased signal which, in four cases, proved to be chronic tendon tears. MRI is useful in evaluating chronic patellar tendinitis because it establishes the diagnosis, detects associated chronic tears, and may help determine appropriate rehabilitation. (orig.)

  6. Magnetic resonance imaging of pelvic endometriosis

    International Nuclear Information System (INIS)

    Twenty-five magnetic resonance imaging (MRI) studies were performed in 18 patients with proven endometriosis. MRI findings were analyzed and compared with laparoscopic or surgical findings; MRI accurately demonstrated ovarian endometrial cysts as well as ectopic foci of endometriosis. Adhesions may be also suggested. Contrary to laparoscopy, MRI easily depicts both deep lesions and endometrial implants under the peritoneum. Consequently, MRI appears as an useful adjunct to laparoscopy for initial diagnosis before starting a medical treatment and above all as the imaging modality of choice for evaluation of the answer to treatment, avoiding iterative and often adhesions limited laparoscopies. (author). 7 refs.; 9 figs

  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 images of chronic patellar tendinitis

    Energy Technology Data Exchange (ETDEWEB)

    Bodne, D.; Quinn, S.F.; Murray, W.T.; Cochran, C.; Bolton, T.; Rudd, S.; Lewis, K.; Daines, P.; Bishop, J.

    1988-01-01

    Chronic patellar tendinitis can be a frustrating diagnostic and therapeutic problem. This report evaluates seven tendons in five patients with chronic patellar tendinitis. The etiologies included 'jumper's knee' and Osgood-Schlatter disease. In all cases magnetic resonance images (MRI) showed thickening of the tendon. Some of the tendons had focal areas of thickening which helped establish the etiology. All cases had intratendinous areas of increased signal which, in four cases, proved to be chronic tendon tears. MRI is useful in evaluating chronic patellar tendinitis because it establishes the diagnosis, detects associated chronic tears, and may help determine appropriate rehabilitation. (orig.)

  10. 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 project...... regard to optimal sampling strategy for detecting motion in four different anatomies on two different MRI scanner brands. A fully implemented interactive real-time MRI system was exploited in a group of healthy fetuses and proved its eligibility as an alternative diagnostic tool for fetal imaging...

  11. Indications for fetal magnetic resonance imaging (MRI)

    International Nuclear Information System (INIS)

    Indications to perform fetal magnetic resonance imaging (MRI) are composed of common ones related to methodological problems of ultrasound (US) assessment (such as for instance hydramnios) and special ones. The latter are related to MR capability of high-resolution soft tissue contrast and an extended field of view that allows visualization of the whole fetus, even in later stages of pregnancy. The most important indications include confirmation of US findings, work-up of malformations with respect to individual prognosis and genetic background, differentiation between acquired conditions and malformations, visualization of pathologies that have to be treated surgically immediately after birth, and morphological changes of the placenta. (orig.)

  12. 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.

  13. 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)

  14. 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…

  15. Magnetism and homogenization of micro-resonators

    CERN Document Server

    Kohn, Robert V

    2007-01-01

    Arrays of cylindrical metal micro-resonators embedded in a dielectric matrix were proposed by Pendry, et. al., in 1999 as a means of creating a microscopic structure that exhibits strong bulk magnetic behavior at frequencies not realized in nature. This behavior arises for H-polarized fields in the quasi-static regime, in which the scale of the micro-structure is much smaller than the free-space wavelength of the fields. We carry out both formal and rigorous two-scale homogenization analyses, paying special attention to the appropriate method of averaging, which does not involve the usual cell averages. We show that the effective magnetic and dielectric coefficients obtained by means of such averaging characterize a bulk medium that, to leading order, produces the same scattering data as the micro-structured composite.

  16. Contrast Agent in Magnetic Resonance Imaging

    DEFF Research Database (Denmark)

    Vu-Quang, Hieu

    2015-01-01

    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...... cancer cells for cancer diagnosis in MRI. F127-Folate coated SPION were stable in various types of suspension medium for over six months. They could specifically target folate receptor of cancer cells in vitro and in vivo thus enhancing the contrast in MRI T2/T2* weighted images. These are preliminary...

  17. 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...

  18. Plasmon coupling of magnetic resonances in an asymmetric gold semishell

    Science.gov (United States)

    Ye, Jian; Kong, Yan; Liu, Cheng

    2016-05-01

    The generation of magnetic dipole resonances in metallic nanostructures is of great importance for constructing near-zero or even negative refractive index metamaterials. Commonly, planar two-dimensional (2D) split-ring resonators or relevant structures are basic elements of metamaterials. In this work, we introduce a three-dimensional (3D) asymmetric Au semishell composed of two nanocups with a face-to-face geometry and demonstrate two distinct magnetic resonances spontaneously in the visible–near infrared optical wavelength regime. These two magnetic resonances are from constructive and destructive hybridization of magnetic dipoles of individual nanocups in the asymmetric semishell. In contrast, complete cancellation of magnetic dipoles in the symmetric semishell leads to only a pronounced electric mode with near-zero magnetic dipole moment. These 3D asymmetric resonators provide new ways for engineering hybrid resonant modes and ultra-high near-field enhancement for the design of 3D metamaterials.

  19. Hybrid resonant phenomenon in a metamaterial structure with integrated resonant magnetic material

    OpenAIRE

    Gollub, Jonah N.; Smith, David R.; Baena, Juan D.

    2008-01-01

    We explore the hybridization of fundamental material resonances with the artificial resonances of metamaterials. A hybrid structure is presented in the waveguide environment that consists of a resonant magnetic material with a characteristic tuneable gyromagnetic response that is integrated into a complementary split ring resonator (CSRR) metamaterial structure. The combined structure exhibits a distinct hybrid resonance in which each natural resonance of the CSRR is split into a lower and up...

  20. Cardiac Magnetic Resonance In Adults With Congenital Heart Disease

    OpenAIRE

    Partington, Sara L.; Valente, Anne Marie

    2013-01-01

    Increasing numbers of adults with congenital heart disease are referred for cardiac magnetic resonance imaging. Knowledge of the congenital heart anatomy, prior surgical interventions, and the development of an imaging focus for each individual patient plays a crucial role when performing a successful cardiac magnetic resonance imaging examination. The following manuscript focuses on cardiac magnetic resonance imaging considerations of three specific conotruncal congenital heart lesions: tetr...

  1. Magnetic resonance imaging of spinal injury.

    Science.gov (United States)

    Tracy, P T; Wright, R M; Hanigan, W C

    1989-03-01

    Magnetic resonance imaging (MRI) was performed on 30 patients following spinal injury (SI). Spin-echo sequences and surface coils were used for all patients. Plain radiographs, high-resolution computed tomography (CT), and MRI were compared for the delineation of bone, disc, and ligament injury, measurement of sagittal spinal canal diameter and subluxation, epidural hematoma, and spinal cord structure. Myelography or intrathecal contrast-enhanced CT were not performed on any of these patients. Magnetic resonance imaging accurately delineated intraspinal pathology in two of four patients with acute penetrating SI, and was normal in the other two patients. In 16 patients with acute nonpenetrating SI, MRI was superior to CT for visualizing injuries to discs, ligaments, and the spinal cord, while CT was superior to MRI in characterizing bony injury. Computed tomography and MRI provided similar measurements of subluxation in six of six patients and of sagittal spinal canal diameter in three of four patients. In ten patients with chronic SI, MRI demonstrated post-traumatic cysts, myelomalacia, spinal cord edema, and the presence or absence of spinal cord compression. In patients with acute penetrating SI and chronic SI, MRI provided comprehensive clinical information. In patients with acute nonpenetrating SI, the information obtained by MRI complemented the data given by plain radiographs and CT, allowing clinical decisions to be made without the need of invasive imaging modalities. PMID:2711244

  2. 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 ...

  3. Magnetic resonance spectroscopy as an imaging method

    International Nuclear Information System (INIS)

    An experimental Magnetic Resonance (MR) system with 4 tesla flux density was set up. For that purpose a data acquisition system and RF coils for resonance frequencies up to 170 MHz were developed. Methods for image guided spectroscopy as well as spectroscopic imaging focussing on the nuclei 1H and 13C were developed and tested on volunteers and selected patients. The advantages of the high field strength with respect to spectroscopic studies were demonstrated. Developments of a new fast imaging technique for the acquisition of scout images as well as a method for mapping and displaying the magnetic field inhomogeneity in-vivo represent contributions to the optimisation of the experimental procedure in spectroscopic studies. Investigations on the interaction of RF radiation with the exposed tissue allowed conclusions regarding the applicability of MR methods at high field strengths. Methods for display and processing of multi-dimensional spectroscopic imaging data sets were developed and existing methods for real-time image synthesis were extended. Results achieved in the field of computer aided analysis of MR images comprised new techniques for image background detection, contour detection and automatic image interpretation as well as knowledge bases for textural representation of medical knowledge for diagnosis. (orig.) With 82 refs., 3 tabs., 75 figs

  4. 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)

  5. 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

  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. Nuclear magnetic resonance imaging and prostatic cancer

    International Nuclear Information System (INIS)

    The diagnosis of prostatic cancer is histological. Apart from rectal examination, only imaging techniques allow evaluation of the extension of the cancer. Magnetic Resonance imaging (MRI) was performed with a Magniscan 5000 (Thomson C.G.R., France) apparatus. Three types of sequences were used: a short RT sequence (30/500, a multi-echo sequence with a long RT (40/2500) and echo gradient sequences (12 scans in less than 3 minutes). The MRI study of the pelvis is favoured by the abundance of fat which gives good contrast, spontaneous visualization of the vessels and the presence of the bladder with a high signal for urine in T2. This provides a very good anatomical study in three planes. In prostatic cancer, the study of the long sequence signal reveals heterogeneity of the prostatic signal on the second echo, but this is a non-specific variation. The staging of prostatic cancer is facilitated by scans in three planes. Different examples are presented in relation to various stages of the disease. Three clinical cases demonstrate that Magnetic Resonance may become an important element in the choice of treatment

  8. Magnetic resonance imaging findings in adnexial torsion

    International Nuclear Information System (INIS)

    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)

  9. 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

  10. Magnetic resonance epidurography with gadolinium-DTPA

    International Nuclear Information System (INIS)

    The aim of this study was to evaluate and describe MRI epidurography as a new imaging tool. Five volunteers and one patient were investigated with MR epidurography after injection of 20 ml Gd-DPTA solution (1 : 250/1 ml Gd-DPTA/250 ml normal saline). Magnetic resonance epidurography is possible. With fat-suppression techniques, the contrast between Gd-DPTA solution in the epidural space and surrounding soft tissue proved adequate. Using the multiplanar capability of MRI with MR epidurography coronal and sagittal projections similar to conventional epidurography, axial slices comparable to CT epidurography can be obtained. Magnetic resonance epidurography is superior to conventional and CT epidurography. Presently, due to high costs as compared with conventional and CT epidurography, MRI is not suitable for the routine monitoring of peridural catheters, but it may have a place in the future with decreasing costs for MRI and for the evaluation of patients with spine pathology, especially in describing epidural processes. (orig.) (orig.)

  11. Magnetic Resonance of Porous Media (MRPM): A perspective

    Science.gov (United States)

    Song, Yi-Qiao

    2013-04-01

    Porous media are ubiquitous in our environment and their application is extremely broad. The common connection between these diverse materials is the importance of the microstructure (μm to mm scale) in determining the physical, chemical and biological functions and properties. Magnetic resonance and its imaging modality have been essential for noninvasive characterization of these materials, in the development of catalysts, understanding cement hydration, fluid transport in rocks and soil, geological prospecting, and characterization of tissue properties for medical diagnosis. The past two decades have witnessed significant development of MRPM that couples advances in physics, chemistry and engineering with a broad range of applications. This article will summarize key advances in basic physics and methodology, examine their limitations and envision future R&D directions.

  12. Phosphorus 31 nuclear magnetic resonance examination of female reproductive tissues

    International Nuclear Information System (INIS)

    Nuclear magnetic resonance spectroscopy is a powerful method of investigating the relationship between metabolism and function in living tissues. We present evidence that the phosphorus 31 spectra of myometrium and placenta are functions of physiologic state and gestational age. Specific spectroscopic abnormalities are observed in association with disorders of pregnancy and gynecologic diseases. Our results suggest that noninvasive nuclear magnetic resonance spectroscopy examinations may sometimes be a useful addition to magnetic resonance imaging examinations, and that nuclear magnetic resonance spectroscopy of biopsy specimens could become a cost-effective method of evaluating certain biochemical abnormalities

  13. Measurements of the frontal and prefrontal lobe volumes by three dimensional magnetic resonance imaging scan. III. Analysis of sex differences with advanced age

    Energy Technology Data Exchange (ETDEWEB)

    Kanemura, Hideaki; Aihara, Masao; Nakazawa, Shinpei [Yamanashi Medical Univ., Tamaho (Japan)

    2002-09-01

    To determine whether there is sex difference in the growth of the frontal and prefrontal lobes, we quantitatively measured the volume of these lobes by three dimensional (3-D) MRI in healthy 12 males (5 months to 39 years) and six females (1 year 11 months to 27 years). The left and right lobes were studied separately. The 3-D MRI data were acquired by the fast spoiled gradient recalled (SPGR) sequence using a 1.5 T MR imager. The frontal and prefrontal lobe volumes were measured by the volume measurement function of the Workstation. In males, the left to right ratio (L/R ratio) of the frontal and prefrontal lobes increased with age. On the contrary, in females, L/R ratio of the frontal and prefrontal lobes showed no significant change with advancing age. These results highlighted sex-specific maturational changes of the frontal and prefrontal lobes and suggested that quantitative data on the frontal and prefrontal lobe are important in interpreting brain abnormalities in children with developmental disorders. (author)

  14. Measurements of the frontal and prefrontal lobe volumes by three dimensional magnetic resonance imaging scan. III. Analysis of sex differences with advanced age

    International Nuclear Information System (INIS)

    To determine whether there is sex difference in the growth of the frontal and prefrontal lobes, we quantitatively measured the volume of these lobes by three dimensional (3-D) MRI in healthy 12 males (5 months to 39 years) and six females (1 year 11 months to 27 years). The left and right lobes were studied separately. The 3-D MRI data were acquired by the fast spoiled gradient recalled (SPGR) sequence using a 1.5 T MR imager. The frontal and prefrontal lobe volumes were measured by the volume measurement function of the Workstation. In males, the left to right ratio (L/R ratio) of the frontal and prefrontal lobes increased with age. On the contrary, in females, L/R ratio of the frontal and prefrontal lobes showed no significant change with advancing age. These results highlighted sex-specific maturational changes of the frontal and prefrontal lobes and suggested that quantitative data on the frontal and prefrontal lobe are important in interpreting brain abnormalities in children with developmental disorders. (author)

  15. Magnetic resonance imaging in laboratory petrophysical core analysis

    Science.gov (United States)

    Mitchell, J.; Chandrasekera, T. C.; Holland, D. J.; Gladden, L. F.; Fordham, E. J.

    2013-05-01

    Magnetic resonance imaging (MRI) is a well-known technique in medical diagnosis and materials science. In the more specialized arena of laboratory-scale petrophysical rock core analysis, the role of MRI has undergone a substantial change in focus over the last three decades. Initially, alongside the continual drive to exploit higher magnetic field strengths in MRI applications for medicine and chemistry, the same trend was followed in core analysis. However, the spatial resolution achievable in heterogeneous porous media is inherently limited due to the magnetic susceptibility contrast between solid and fluid. As a result, imaging resolution at the length-scale of typical pore diameters is not practical and so MRI of core-plugs has often been viewed as an inappropriate use of expensive magnetic resonance facilities. Recently, there has been a paradigm shift in the use of MRI in laboratory-scale core analysis. The focus is now on acquiring data in the laboratory that are directly comparable to data obtained from magnetic resonance well-logging tools (i.e., a common physics of measurement). To maintain consistency with well-logging instrumentation, it is desirable to measure distributions of transverse (T2) relaxation time-the industry-standard metric in well-logging-at the laboratory-scale. These T2 distributions can be spatially resolved over the length of a core-plug. The use of low-field magnets in the laboratory environment is optimal for core analysis not only because the magnetic field strength is closer to that of well-logging tools, but also because the magnetic susceptibility contrast is minimized, allowing the acquisition of quantitative image voxel (or pixel) intensities that are directly scalable to liquid volume. Beyond simple determination of macroscopic rock heterogeneity, it is possible to utilize the spatial resolution for monitoring forced displacement of oil by water or chemical agents, determining capillary pressure curves, and estimating

  16. Secondary resonance magnetic force microscopy using an external magnetic field for characterization of magnetic thin films

    Science.gov (United States)

    Liu, Dongzi; Mo, Kangxin; Ding, Xidong; Zhao, Liangbing; Lin, Guocong; Zhang, Yueli; Chen, Dihu

    2015-09-01

    A bimodal magnetic force microscopy (MFM) that uses an external magnetic field for the detection and imaging of magnetic thin films is developed. By applying the external modulation magnetic field, the vibration of a cantilever probe is excited by its magnetic tip at its higher eigenmode. Using magnetic nanoparticle samples, the capacity of the technique which allows single-pass imaging of topography and magnetic forces is demonstrated. For the detection of magnetic properties of thin film materials, its signal-to-noise ratio and sensitivity are demonstrated to be superior to conventional MFM in lift mode. The secondary resonance MFM technique provides a promising tool for the characterization of nanoscale magnetic properties of various materials, especially of magnetic thin films with weak magnetism.

  17. 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 ...

  18. 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...

  19. 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

  20. Nuclear magnetic resonance in hexaferrite/maghemite composite nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Kříšťan, P.; Hondlík, O.; Štěpánková, H.; Chlan, V.; Kouřil, K.; Řezníček, R.; Pollert, Emil; Veverka, Pavel

    Warszawa: Polish Academy of Sciences, 2015, s. 514-516. ISSN 0587-4246. [The European Conference PHYSICS OF MAGNETISM 2014/PM'14/. Poznań (PL), 23.06.2014-27.06.2014] Institutional support: RVO:68378271 Keywords : nuclear magnetic resonance and relaxation * ferrimagnetics * fine-particle systems * nanocrystalline materials * magnetic oxides * inorganic compounds Subject RIV: BM - Solid Matter Physics ; Magnetism

  1. Advanced Manufacturing of Superconducting Magnets

    Science.gov (United States)

    Senti, Mark W.

    1996-01-01

    The development of specialized materials, processes, and robotics technology allows for the rapid prototype and manufacture of superconducting and normal magnets which can be used for magnetic suspension applications. Presented are highlights of the Direct Conductor Placement System (DCPS) which enables automatic design and assembly of 3-dimensional coils and conductor patterns using LTS and HTS conductors. The system enables engineers to place conductors in complex patterns with greater efficiency and accuracy, and without the need for hard tooling. It may also allow researchers to create new types of coils and patterns which were never practical before the development of DCPS. The DCPS includes a custom designed eight-axis robot, patented end effector, CoilCAD(trademark) design software, RoboWire(trademark) control software, and automatic inspection.

  2. Magnetic resonance imaging of vertebral compression fractures

    International Nuclear Information System (INIS)

    Magnetic resonance (MR) imaging was performed on 112 patients with 210 vertebral compression fractures. Forty fractures were due to malignancy; 170 were caused by benign process. Pathological fractures showed low signal intensity (SI) on T1 weighted image (WI) and various SI on T2 WI. In 39 of the 40 fractures caused by malignancy, MRI showed complete replacement of normal bone marrow. Other findings of pathological fractures, such as involvement of posterior structures, paraspinal soft tissue masses, are useful for discrimination between benign and pathologic compression fractures. In 120 of the 157 fractures caused osteoporosis had complete preservation of normal bone marrow and isointense or high intense marrow SI on T1 WI and T2 WI. Compression fractures caused by trauma showed low SI on T1 WI and high SI on T2 WI with an irregular pattern. We suppose MRI may be a useful modality in differenciating benign and metastatic fractures. (author)

  3. Modern magnetic resonance imaging of the liver

    International Nuclear Information System (INIS)

    Magnetic resonance imaging (MRI) of the liver has become an essential tool in the radiological diagnostics of both focal and diffuse diseases of the liver and is subject to constant change due to technological progress. Recently, important improvements could be achieved by innovations regarding MR hardware, sequences and postprocessing methods. The diagnostic spectrum of MRI could be broadened particularly due to new examination sequences, while at the same time scanning time could be shortened and image quality has been improved. The aim of this article is to explain both the technological background and the clinical application of recent MR sequence developments and to present the scope of a modern MRI protocol for the liver. (orig.)

  4. Magnetic resonance imaging for postoperative maxillary cyst

    International Nuclear Information System (INIS)

    Magnetic resonance images of 47 patients with postoperative maxillary cyst were analyzed for size, location, and signal intensity. The smallest cyst was confirmed at surgery to be 1 cmx1 cmx1 cm and the largest 5 cmx5 cmx5 cm. The cysts were usually found in the superomedial and inferomedial parts of the maxillary sinus (44%). Many patients (60%) had multiple cysts or bilateral cysts (30%). In most the signal intensity was low in the T1-weighted SE (500/40) images and high in the T2-weighted SE (2000/80) images. Cysts with a hemorrhagic component, though rare, showed high signal intensity in both T1-and T2-weighted images. (author)

  5. 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

  6. 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

  7. Magnetic resonance imaging in tuberous sclerosis

    International Nuclear Information System (INIS)

    Two patients with tuberous sclerosis, who had the typical computed tomographic (CT) sign (calcified subependymal nodules), underwent magnetic resonance imaging (MRI) using inversion-recovery (IR) and spin-echo (SE) techniques. Subependymal nodules were discriminated from parenchymal nodules on IR and SE images and on T1-weighted images in one patient. Subependymal nodules were visualized as well in another patient. However, either IR or SE images failed to show nodules in the frontal lobe or caudate nucleus. Nor was nodules in the cerebellar odontoid nucleus detected on IR images. These results suggest the difficulty in uniformity of MRI findings. On the contrary, pathological difference in nudules may reflect relaxation times, probably causing the differences in IR and SE images. (Namekawa, K.)

  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. 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

  10. 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

  11. Magnetic resonance imaging of ovarian cystic tumor

    International Nuclear Information System (INIS)

    Seventeen cases with cystic ovarian tumors were examined with both magnetic resonance imaging (MRI) and CT scanning. The contents of the cysts were analyzed as for protein, fat, and iron. The intensity patterns of the cystic lesion were not directly related to the amount of protein, fat, nor iron. But an for the cystadenomas, protein concentration are the most responsible for their intensities, and as for the dermoid cysts, fat are the most responsible for. And in endemetrial cysts, it seems that variable amount of protein, fat, and iron make the unique intensity patterns. MRI was superior to CT in characterizing cyts especially for cystadenoma and endmetorial cysts. And with much more case studies, relationship between protein concentration and intensities will be proved. (author)

  12. Magnetic resonance imaging of traumatic cervical injury

    International Nuclear Information System (INIS)

    To evaluate magnetic resonance imaging (MRI) findings of cevical injuries. MRI studies of 34 patients with cervical spinal injuries were analyzed retrospectively. All MRI scans were obtained with an 1.0T superconductive MRI scanner (Siemens Magnetom 42SPE) and their findings were analyzed regarding the spinal cord, bony spine, ligaments, and intervertebral disks. A variety of abnormal findings were detected: 25 cord abnormalities including cord compression (15 cases), cord edema (4 cases), syringomyelia (4 cases), myelomalacia (1 case), and hemorrhagic contusion (1 case), 18 ligamentous injuries, 22 disk herniations (9 post-traumatic, 13 chronic degenerative), 11 spine fractures, and 4 subluxations. MRI is useful in evaluating the spinal cord itself, in depicting ligamentous injuries, in establishing the presence of disc herniation, and in assessing the alignment of cervical spine

  13. Magnetic resonance imaging of traumatic cervical injury

    Energy Technology Data Exchange (ETDEWEB)

    Juhng, S. K.; Lee, K. S.; Sohn, K. J.; Choi, S. S.; Won, J. J. [Wonkwang University School of Medicine, Iri (Korea, Republic of)

    1994-04-15

    To evaluate magnetic resonance imaging (MRI) findings of cevical injuries. MRI studies of 34 patients with cervical spinal injuries were analyzed retrospectively. All MRI scans were obtained with an 1.0T superconductive MRI scanner (Siemens Magnetom 42SPE) and their findings were analyzed regarding the spinal cord, bony spine, ligaments, and intervertebral disks. A variety of abnormal findings were detected: 25 cord abnormalities including cord compression (15 cases), cord edema (4 cases), syringomyelia (4 cases), myelomalacia (1 case), and hemorrhagic contusion (1 case), 18 ligamentous injuries, 22 disk herniations (9 post-traumatic, 13 chronic degenerative), 11 spine fractures, and 4 subluxations. MRI is useful in evaluating the spinal cord itself, in depicting ligamentous injuries, in establishing the presence of disc herniation, and in assessing the alignment of cervical spine.

  14. Monitoring angiogenesis using magnetic resonance methods

    DEFF Research Database (Denmark)

    Holm, David Alberg

    2008-01-01

    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...... adults where it is primaily found in wound healing, pregnancy and during the menstrual cycle. This thesis focus on the negative consequences of angiogenesis in cancer. It consists of a an initial overview followed by four manuscripts. The overview gives a short introduction to the process of angiogenesis...... 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...

  15. Magnetic resonance tomography and ultrasound in rheumatology

    International Nuclear Information System (INIS)

    Technical innovations and software improvements in magnetic resonance imaging (MRI) and high-resolution sonography (US) have definitely influenced the diagnostic imaging of rheumatic diseases. For MRI, improvements in surface coils, dedicated low-field systems (0.2 T), and software improvements (shorter acquisition times and refinements of fat suppressing techniques) must be mentioned. For sonography, the main innovations concern the development of higher transducer frequencies (7-15 Mhz) and power Doppler imaging. Clinical evaluations have shown that MRI and US are most useful in cases of suspected rheumatic disease with negative plain film radiographs and for documenting the course of the disease, diagnosing of early rheumatoid arthritis, making a differential diagnosis in clinically unclear rheumatic diseases, investigating vascularization, and quantifying pannus formation. In order to improve diagnostic efficacy the role of MRI and US in the management of patients with rheumatic disease should be reconsidered. (orig.)

  16. Multivoxel Magnetic Resonance Spectroscopy in Gliomatosis Cerebri

    International Nuclear Information System (INIS)

    Gliomatosis cerebri is a rare entity with non-specific clinical and conventional magnetic resonance imaging (MRI) findings; accurate diagnosis is a differential diagnostic challenge. MR spectroscopy has recently been introduced as a useful diagnostic tool for detection of this entity. We present a gliomatosis cerebri case in which we made the radiological diagnosis using the MR spectroscopy findings; the diagnosis was confirmed by subsequent biopsy and histopathologic evaluation. Multivoxel spectroscopy (CSI, PRESS, 1500/135) shows a marked increase in Cho/NAA (6.6), normal to mild increase in Cho/Cr (1.2), and marked decrease in NAA/Cr (0.2) compared with the normally appearing contralateral side (Cho/NAA: 0.8, Cho/Cr: 0.9, NAA/Cr: 1.2)

  17. 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)

  18. Magnetic resonance imaging of intervertebral disc degeneration

    International Nuclear Information System (INIS)

    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.)

  19. [Prostate biopsy under magnetic resonance imaging guidance].

    Science.gov (United States)

    Kuplevatskiy, V I; CherkashiN, M A; Roshchin, D A; Berezina, N A; Vorob'ev, N A

    2016-01-01

    Prostate cancer (PC) is one of the most important problems in modern oncology. According to statistical data, PC ranks second in the cancer morbidity structure in the Russian Federation and developed countries and its prevalence has been progressively increasing over the past decade. A need for early diagnosis and maximally accurate morphological verification of the diagnosis in difficult clinical cases (inconvenient tumor location for standard transrectal biopsy; gland scarring changes concurrent with prostatitis and hemorrhage; threshold values of prostate-specific antigen with unclear changes in its doubling per unit time; suspicion of biochemical recurrence or clinical tumor progression after special treatment) leads to revised diagnostic algorithms and clinically introduced new high-tech invasive diagnostic methods. This paper gives the first analysis of literature data on Russian practice using one of the new methods to verify prostate cancer (transrectal prostate cancer under magnetic resonance imaging (MRI) guidance). The have sought the 1995-2015 data in the MEDLINE and Pubmed. PMID:27192773

  20. 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

  1. Magnetic resonance imaging of facial muscles

    Energy Technology Data Exchange (ETDEWEB)

    Farrugia, M.E. [Department of Clinical Neurology, University of Oxford, Radcliffe Infirmary, Oxford (United Kingdom)], E-mail: m.e.farrugia@doctors.org.uk; Bydder, G.M. [Department of Radiology, University of California, San Diego, CA 92103-8226 (United States); Francis, J.M.; Robson, M.D. [OCMR, Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford (United Kingdom)

    2007-11-15

    Facial and tongue muscles are commonly involved in patients with neuromuscular disorders. However, these muscles are not as easily accessible for biopsy and pathological examination as limb muscles. We have previously investigated myasthenia gravis patients with MuSK antibodies for facial and tongue muscle atrophy using different magnetic resonance imaging sequences, including ultrashort echo time techniques and image analysis tools that allowed us to obtain quantitative assessments of facial muscles. This imaging study had shown that facial muscle measurement is possible and that useful information can be obtained using a quantitative approach. In this paper we aim to review in detail the methods that we applied to our study, to enable clinicians to study these muscles within the domain of neuromuscular disease, oncological or head and neck specialties. Quantitative assessment of the facial musculature may be of value in improving the understanding of pathological processes occurring within facial muscles in certain neuromuscular disorders.

  2. 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.

  3. 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.

  4. Magnetic resonance imaging of the musculoskeletal system

    International Nuclear Information System (INIS)

    Ever since the advent of computed tomography reliable determinations of the extension of musculoskeletal tumours have been possible before surgical intervention. It is basically owing to this technique that limb-sparing partial resection can now be performed as an alternative to amputation of an extremity. Magnetic resonance imaging is even more suitable for preoperative tumour staging, as skip lesions and the intraosseous or extraosseous spread of the tumour are more clearly discernible here than on CT displays. For evaluations of the type and severity of bone tumours that have not yet been analysed histologically survey radiography still appears to be the obvious method. CT and MRT, on the other hand, provide information as to the texture of the tumour matrix (fatty, liquid or solid consistency, tinges of blood). Some types of tumour seem to be associated with a particular morphological appearance in MRT images. (orig.)

  5. Magnetic resonance imaging in joint diseases

    International Nuclear Information System (INIS)

    Magnetic resonance imaging has proven an invaluable method in the diagnosis of joint diseases associated with osteonecrotic, inflammatory, traumatic and degenerative processes. At the clinical level, it has an important role in decisions about the method of treatment and evaluations of the therapeutic success. When the merits of MRT are balanced against those of conventional radiography including tomography and CT, which both ensure better spatial resolution in the visualisation of cortical and spongy bone structures, it becomes quite evident that MRT must not be regarded as an alternative method of imaging but as one that can be used additionally to obtain the most information for the diagnosis of arthropathy. The question as to whether new pulse sequences (snap shots) or invasive techniques like intra-articular injection of paramagnetic substances (MR arthrography) are likely to become routine procedures in the detection of joint diseases using MRT remains to be examined in further studies. (orig.)

  6. 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...

  7. 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.

  8. [Magnetic resonance urography in pediatric urology].

    Science.gov (United States)

    Schindele, D; Furth, C; Liehr, U B; Porsch, M; Baumunk, D; Janitzky, A; Wendler, J J; Genseke, P; Ricke, J; Schostak, M

    2012-12-01

    Magnetic resonance urography (MRU) provides high resolution imaging of the urogenital system and the use of paramagnetic contrast agents enables a functional depiction. This review summarizes existing data concerning this diagnostic procedure in pediatric urology. A systematic search and assessment of the literature was performed.A total of 12 studies were reviewed in detail. In mostly small study populations a great heterogeneity concerning methodology, use of comparative examinations and standards of reference was noted. Besides the quality of anatomical imaging, the functional study of renal excretory function and differential renal function was also assessed. Only a few studies performed statistical analyses.The authors' rating of MRU was mostly positive. Due to methodical weaknesses, lack of independent standards of reference and statistical analyses the overall level of evidence was low. Further high quality studies will be necessary to assess the value of MRU for the diagnostic workup in pediatric urology. PMID:23160606

  9. Magnetic resonance imaging in head injury

    International Nuclear Information System (INIS)

    Magnetic resonance imaging (MRI) and computed tomography (CT) scan were compared to define their roles in the evaluation of head injured patients. MRI was found to be equal or inferior to CT scan in detection of extraparenchymatous lesions due to a failure of CT scan to indentify ultra-early hemorrhage. While, MRI was far superior to CT scan in regard to the indentification of the intraparenchymatous lesions in the acute stage of head injury. The lesions in the central structure suggesting diffuse axonal injury (DAI) were commonly found in the patients showing lower Glasgow Coma Scale score, though the degree of central structure damage shown in MRI was not correlated with the neurological grading and outcome. We concluded that DAI may play a major role in the severe head injury, but the severity of DAI is not predictable by using MRI. (author)

  10. Contrast-enhanced magnetic resonance angiography

    International Nuclear Information System (INIS)

    Magnetic resonance angiography (MRA) protocols are based on standard sequence protocols like time of flight MRA, which evaluates inflowing spins. This technique is limited by a variety of artifacts like the saturation artifact via turbulent blood flow. Contrast media diminish these artifacts like extracellular agents and blood-pool contrast media. The clinical value of the contrast-enhanced MRA for cerebral pathologies is based on the use of the paramagnetic contrast agent Gd-DTPA. For extracerebral diseases this technique is restricted because of the simultaneous visualization of both arterial and venous vascular territorities. Occult venous sinus thrombosis or AV malformations are clinical essential indications for the use of C-MRA. Experimental data prove the excellent contrast abilities of blood-pool agents like Gd-DTPA-polylysin or Gd-DTPA-albumin, which demonstrate long intravascular persistence and retarded excretion. (orig.)

  11. Magnetic resonance imaging of intramuscular metastases

    International Nuclear Information System (INIS)

    The aim of the present study was to analyse magnetic resonance findings of intramuscular metastases (IM) in a relatively large series. From January 2000 to January 2010, 28 patients (207 metastases) were retrospectively identified in the radiological database of the Martin-Luther-University. Several different scanning protocols were used depending on the localisation of IM. In 12 patients diffusion-weighted (DW) images were obtained with a multi-shot SE-EPI sequence. Apparent diffusion coefficient (ADC) maps were also calculated. Furthermore, fusion images were manually generated between the DW and half-Fourier acquisition single-shot turbo spin echo (HASTE) images. On T2-weighted images, 97% of the recognised IM were hyperintense in comparison to unaffected musculature, and 3% were mixed iso- to hyperintense. On T1-weighted images most IM (91%) were homogeneously isointense in comparison to muscle tissue, whereas 4% were hypointense, and 5% lightly hyperintense. ADC maps were calculated for 91 metastases ranging from 0.99 to 4.00 mm2s-1 (mean value 1.99 ± 0.66). ADC values of low (3.0) in 6%. Of the IM that were investigated with contrast medium, 88.5% showed marked enhancement. It was homogeneous in 88% and heterogenous in 6%. Rim enhancement with central low attenuation was seen in 6%. There was no difference in enhancement characteristics with respect to ADC values or fusion patterns. Peritumoral enhancement was identified in 2.4%. Magnetic resonance features of muscle metastases are relatively typical and consist of round or oval intramuscular masses with well-defined margins, marked enhancement, low or moderate ADC values, and moderate to high signal intensity on fusion images. (orig.)

  12. Magnetic resonance imaging of intramuscular metastases

    Energy Technology Data Exchange (ETDEWEB)

    Surov, Alexey; Spielmann, Rolf-Peter; Behrmann, Curd [Martin-Luther-University Halle-Wittenberg, Department of Radiology, Halle (Germany); Fiedler, Eckhard [Martin-Luther-University Halle-Wittenberg, Department of Dermatology and Venereology, Halle (Germany); Voigt, Wieland [Martin-Luther-University Halle-Wittenberg, Department of Oncology, Halle (Germany); Wienke, Andreas [Martin-Luther-University Halle-Wittenberg, Department of Biometry, Halle (Germany); Holzhausen, Hans-Juergen [Martin-Luther-University Halle-Wittenberg, Department of Pathology, Halle (Germany)

    2011-04-15

    The aim of the present study was to analyse magnetic resonance findings of intramuscular metastases (IM) in a relatively large series. From January 2000 to January 2010, 28 patients (207 metastases) were retrospectively identified in the radiological database of the Martin-Luther-University. Several different scanning protocols were used depending on the localisation of IM. In 12 patients diffusion-weighted (DW) images were obtained with a multi-shot SE-EPI sequence. Apparent diffusion coefficient (ADC) maps were also calculated. Furthermore, fusion images were manually generated between the DW and half-Fourier acquisition single-shot turbo spin echo (HASTE) images. On T2-weighted images, 97% of the recognised IM were hyperintense in comparison to unaffected musculature, and 3% were mixed iso- to hyperintense. On T1-weighted images most IM (91%) were homogeneously isointense in comparison to muscle tissue, whereas 4% were hypointense, and 5% lightly hyperintense. ADC maps were calculated for 91 metastases ranging from 0.99 to 4.00 mm{sup 2}s{sup -1} (mean value 1.99 {+-} 0.66). ADC values of low (<1.5) signal intensity (SI) were identified in 26%, moderate SI (from 1.5 to 3.0) in 68%, and high SI (>3.0) in 6%. Of the IM that were investigated with contrast medium, 88.5% showed marked enhancement. It was homogeneous in 88% and heterogenous in 6%. Rim enhancement with central low attenuation was seen in 6%. There was no difference in enhancement characteristics with respect to ADC values or fusion patterns. Peritumoral enhancement was identified in 2.4%. Magnetic resonance features of muscle metastases are relatively typical and consist of round or oval intramuscular masses with well-defined margins, marked enhancement, low or moderate ADC values, and moderate to high signal intensity on fusion images. (orig.)

  13. 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.

  14. Magnetic resonance imaging of cerebellar Schistosomiasis mansoni

    International Nuclear Information System (INIS)

    A 15-year-old boy was admitted to hospital with a history of headache, dizziness, vomiting and double vision that started two weeks before. His parents denied any previous disease. During clinical examination he presented diplopia on lateral gaze to the left and horizontal nystagmus. No major neurological dysfunction was detected. He was well built, mentally responsive and perceptive. Laboratory findings revealed a leukocyte count of 10,000/mL, a normal red blood cell count and no eosinophilia. The magnetic resonance images (MRI) of the brain showed a left cerebellar lesion with mass effect compressing the surrounding tissues. Contrast-enhanced images showed a mass like structure and punctate nodules (Figures A and B: axial and coronal contrast-enhanced T1-weighted MR images showed the nodular - yellow arrows - enhancement pattern of a left cerebellar intraxial lesion). The lesion extended to the vermis and brachium pons and compressed the medulla. There was no hydrocephalus. He was taken to the operating room with the presumptive diagnosis of a neuroglial tumor, and submitted to a lateral suboccipital craniectomy. A brown, brittle tumoral mass without a clearly defined margin with the cerebellar tissue was removed. Microscopic examination revealed schistosomal granulomas in the productive phase in the cerebellum (Figure C). After surgery, treatment with praziquantel (50 mg/kg/dia, single dose) and prednisone (1 mg/kg/day) was offered and the patient improved quickly. Thirty days later he was seen again at the outpatient clinic: he was asymptomatic and with no neurological impairment. This is the eighth case of cerebellar involvement in schistosomiasis mansoni and the second report of a tumoral form of cerebellar schistosomiasis documented by magnetic resonance images. (author)

  15. Magnetic resonance techniques for investigation of multiple sclerosis

    Science.gov (United States)

    MacKay, Alex; Laule, Cornelia; Li, David K. B.; Meyers, Sandra M.; Russell-Schulz, Bretta; Vavasour, Irene M.

    2014-11-01

    Multiple sclerosis (MS) is a common neurological disease which can cause loss of vision and balance, muscle weakness, impaired speech, fatigue, cognitive dysfunction and even paralysis. The key pathological processes in MS are inflammation, edema, myelin loss, axonal loss and gliosis. Unfortunately, the cause of MS is still not understood and there is currently no cure. Magnetic resonance imaging (MRI) is an important clinical and research tool for MS. 'Conventional' MRI images of MS brain reveal bright lesions, or plaques, which demark regions of severe tissue damage. Conventional MRI has been extremely valuable for the diagnosis and management of people who have MS and also for the assessment of therapies designed to reduce inflammation and promote repair. While conventional MRI is clearly valuable, it lack pathological specificity and, in some cases, sensitivity to non-lesional pathology. Advanced MR techniques have been developed to provide information that is more sensitive and specific than what is available with clinical scanning. Diffusion tensor imaging and magnetization transfer provide a general but non-specific measure of the pathological state of brain tissue. MR spectroscopy provides concentrations of brain metabolites which can be related to specific pathologies. Myelin water imaging was designed to assess brain myelination and has proved useful for measuring myelin loss in MS. To combat MS, it is crucial that the pharmaceutical industry finds therapies which can reverse the neurodegenerative processes which occur in the disease. The challenge for magnetic resonance researchers is to design imaging techniques which can provide detailed pathological information relating to the mechanisms of MS therapies. This paper briefly describes the pathologies of MS and demonstrates how MS-associated pathologies can be followed using both conventional and advanced MR imaging protocols.

  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. 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.

  18. 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...... intraluminal thrombus specimens to the appearance on magnetic resonance imaging....

  19. 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.

  20. 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...

  1. 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

  2. Magnetic resonance characterization of silicon nanowires

    Science.gov (United States)

    Fanciulli, Marco; Belli, Matteo; Vellei, Antonio; Canevali, Carmen; Rotta, Davide; Paleari, Stefano; Basini, Martina

    2012-02-01

    Silicon nanowires (SiNWs) have been extensively investigated in the last decades. The interest in these nanostructures stems from both fundamental and applied research motivations. The functional properties of one- and zero-dimensional silicon structures are significantly different, at least below a certain critical dimension, from those well known in the bulk. The key and peculiar functional properties of SiNWs find applications in nanoelectronics, classical and quantum information processing and storage, optoelectronics, photovoltaics, thermoelectric, battery technology, nano-biotechnology, and neuroelectronics. We report our work on the characterization by continuous wave (CW) and pulse electron spin resonance (CW, FT-EPR) and electrically detected magnetic resonance (EDMR) measurements of silicon nanowires (SiNWs) produced by different top-down processes. SiNWs were fabricated starting from SOI wafers using standard e-beam lithography and anisotropic wet etching or by metal-assisted chemical etching. Further oxidation was used to reduce the wire cross section. Different EDMR implementations were used to address the electronic wave function of donors (P, As) and to characterize point defects at the SiNWs/SiO2 interface.

  3. Selectivity in multiple quantum nuclear magnetic resonance

    International Nuclear Information System (INIS)

    The observation of multiple-quantum nuclear magnetic resonance transitions in isotropic or anisotropic liquids is shown to give readily interpretable information on molecular configurations, rates of motional processes, and intramolecular interactions. However, the observed intensity of high multiple-quantum transitions falls off dramatically as the number of coupled spins increases. The theory of multiple-quantum NMR is developed through the density matrix formalism, and exact intensities are derived for several cases (isotropic first-order systems and anisotropic systems with high symmetry) to shown that this intensity decrease is expected if standard multiple-quantum pulse sequences are used. New pulse sequences are developed which excite coherences and produce population inversions only between selected states, even though other transitions are simultaneously resonant. One type of selective excitation presented only allows molecules to absorb and emit photons in groups of n. Coherent averaging theory is extended to describe these selective sequences, and to design sequences which are selective to arbitrarily high order in the Magnus expansion. This theory and computer calculations both show that extremely good selectivity and large signal enhancements are possible

  4. 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.

  5. Cardiac magnetic resonance imaging of a patient with an magnetic resonance imaging conditional permanent pacemaker

    OpenAIRE

    Chris B. Pepper; Mohan Sivananthan; Artis, Nigel J.; Hogarth, Andrew J.

    2011-01-01

    Cardiac Magnetic Resonance Imaging (MRI) is increasingly used as the optimum modality for cardiac imaging. An aging population and rising numbers of patients with permanent pacemakers means many such individuals may require cardiac MRI scanning in the future. Whilst the presence of a permanent pacemaker is historically regarded as a contra-indication to MRI scanning, pacemaker systems have been developed to limit any associated risks. No reports have been published regarding the use of such d...

  6. Plasma-induced magnetic responses during nonlinear dynamics of magnetic islands due to resonant magnetic perturbations

    International Nuclear Information System (INIS)

    Resonant magnetic perturbations (RMPs) produce magnetic islands in toroidal plasmas. Self-healing (annihilation) of RMP-induced magnetic islands has been observed in helical systems, where a possible mechanism of the self-healing is shielding of RMP penetration by plasma flows, which is well known in tokamaks. Thus, fundamental physics of RMP shielding is commonly investigated in both tokamaks and helical systems. In order to check this mechanism, detailed informations of magnetic island phases are necessary. In experiments, measurement of radial magnetic responses is relatively easy. In this study, based on a theoretical model of rotating magnetic islands, behavior of radial magnetic fields during the self-healing is investigated. It is confirmed that flips of radial magnetic fields are typically observed during the self-healing. Such behavior of radial magnetic responses is also observed in LHD experiments

  7. 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.

  8. 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

  9. Multiparametric [18F]Fluorodeoxyglucose/ [18F]Fluoromisonidazole Positron Emission Tomography/ Magnetic Resonance Imaging of Locally Advanced Cervical Cancer for the Non-Invasive Detection of Tumor Heterogeneity: A Pilot Study

    Science.gov (United States)

    Andrzejewski, Piotr; Baltzer, Pascal; Polanec, Stephan H.; Sturdza, Alina; Georg, Dietmar; Helbich, Thomas H.; Karanikas, Georgios; Grimm, Christoph; Polterauer, Stephan; Poetter, Richard; Wadsak, Wolfgang; Mitterhauser, Markus; Georg, Petra

    2016-01-01

    Objectives To investigate fused multiparametric positron emission tomography/magnetic resonance imaging (MP PET/MRI) at 3T in patients with locally advanced cervical cancer, using high-resolution T2-weighted, contrast-enhanced MRI (CE-MRI), diffusion-weighted imaging (DWI), and the radiotracers [18F]fluorodeoxyglucose ([18F]FDG) and [18F]fluoromisonidazol ([18F]FMISO) for the non-invasive detection of tumor heterogeneity for an improved planning of chemo-radiation therapy (CRT). Materials and Methods Sixteen patients with locally advanced cervix were enrolled in this IRB approved and were examined with fused MP [18F]FDG/ [18F]FMISO PET/MRI and in eleven patients complete data sets were acquired. MP PET/MRI was assessed for tumor volume, enhancement (EH)-kinetics, diffusivity, and [18F]FDG/ [18F]FMISO-avidity. Descriptive statistics and voxel-by-voxel analysis of MRI and PET parameters were performed. Correlations were assessed using multiple correlation analysis. Results All tumors displayed imaging parameters concordant with cervix cancer, i.e. type II/III EH-kinetics, restricted diffusivity (median ADC 0.80x10-3mm2/sec), [18F]FDG- (median SUVmax16.2) and [18F]FMISO-avidity (median SUVmax3.1). In all patients, [18F]FMISO PET identified the hypoxic tumor subvolume, which was independent of tumor volume. A voxel-by-voxel analysis revealed only weak correlations between the MRI and PET parameters (0.05–0.22), indicating that each individual parameter yields independent information and the presence of tumor heterogeneity. Conclusion MP [18F]FDG/ [18F]FMISO PET/MRI in patients with cervical cancer facilitates the acquisition of independent predictive and prognostic imaging parameters. MP [18F]FDG/ [18F]FMISO PET/MRI enables insights into tumor biology on multiple levels and provides information on tumor heterogeneity, which has the potential to improve the planning of CRT. PMID:27167829

  10. 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...

  11. 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

  12. 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.)

  13. Metamaterial radiofrequency lens for magnetic resonance imaging

    CERN Document Server

    Freire, Manuel J; Jelinek, Lukas; Gil, Eduardo; Moya, Francisco

    2009-01-01

    The purpose of this work is to test the ability of a new class of passive electromagnetic device to increase the penetration depth of phased arrays of surface coils for magnetic resonance (MR) imaging systems. This new device is based on the emerging technology of metamaterials and behaves like a lens for the radiofrequency magnetic fields. The presented device was tested in several 1.5-T MR systems from different companies in combination with different phased arrays. One of the authors was enrolled as volunteer for the experiments. In these experiments his knees were imaged by using a dual phased array. The device was placed between the knees to check that the penetration depth of the coils was improved by this passive device. In all the experiments the presented device was successfully tested and it was checked that the knees of the volunteer can be imaged at deeper distances and that the signal-to-noise-ratio (SNR) in the obtained MR images was improved by the presence of the lens. The presented device has...

  14. Italian registry of cardiac magnetic resonance

    International Nuclear Information System (INIS)

    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

  15. Magnetic resonance imaging of the adrenal lesions

    International Nuclear Information System (INIS)

    Magnetic resonance imaging (MRI) was performed in 18 patients with adrenal masses using a superconducting magnet operating at 1.5 Tesla. Seven pheochromocytomas, five aldosterone-producing adenomas, two hydrocortisone-producing adenomas, two adrenal metastases, one adrenal carcinoma and one adrenal myelolipoma were examined by this method. Spin-echo pulse sequences were obtained at the repetition time (TR) 0.1 ∼ 1.6 sec and the echo time (TE) 14 ∼ 75 msec. T1-weighted images of phechromocytomas were similar in signal intensity to the kidney, while T2-weighted images revealed much higher intensity than those of the liver and kidney. The signal intensity on T1-and T2-weighted images of adrenal adenomas were similar, irrespective of endocrine characteristics, to that of the liver and kidney. T1-weighted images which detect small masses more than 1 cm in diameter offer anatomic resolution similar to computed tomography (CT) and T2-weighted images give information about internal characteristic of adrenal masses. It is expected that MRI is more useful in diagnosis of adrenal masses than CT. (author)

  16. 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.

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

    International Nuclear Information System (INIS)

    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. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  18. 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.

  19. 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

  20. 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

  1. Magnetic resonance imaging markers for early diagnosis of Parkinson's disease

    Institute of Scientific and Technical Information of China (English)

    Silvia Marino; Rosella Ciurleo; Giuseppe Di Lorenzo; Marina Barresi; Simona De Salvo; Sabrina Giacoppo; Alessia Bramanti; Pietro Lanzafame; Placido Bramanti

    2012-01-01

    Parkinson's disease (PD) is a neurodegenerative disorder characterized by selective and progressive degeneration, as well as loss of dopaminergic neurons in the substantia nigra. In PD, approximately 60-70% of nigrostriatal neurons are degenerated and 80% of content of the striatal dopamine is reduced before the diagnosis can be established according to widely accepted clinical diagnostic criteria. This condition describes a stage of disease called "prodromal", where non-motor symptoms, such as olfactory dysfunction, constipation, rapid eye movement behaviour disorder, depression, precede motor sign of PD. Detection of prodromal phase of PD is becoming an important goal for determining the prognosis and choosing a suitable treatment strategy. In this review, we present some non-invasive instrumental approaches that could be useful to identify patients in the prodromal phase of PD or in an early clinical phase, when the first motor symptoms begin to be apparent. Conventional magnetic resonance imaging (MRI) and advanced MRI techniques, such as magnetic resonance spectroscopy imaging, diffusion-weighted and diffusion tensor imaging and functional MRI, are useful to differentiate early PD with initial motor symptoms from atypical parkinsonian disorders, thus, making easier early diagnosis. Functional MRI and diffusion tensor imaging techniques can show abnormalities in the olfactory system in prodromal PD.

  2. 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 and...... wherein said first conductive wire and said one or more capacitors are located outside of said internal volume, wherein the internal volume of the hollow waveguide defines an imaging volume or sample volume....

  3. Applications of magnetic resonance imaging and magnetic resonance angiography to evaluate the hepatic vasculature in the pediatric patient

    International Nuclear Information System (INIS)

    Magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) offer several techniques to evaluate the hepatic vasculature. These techniques are briefly reviewed with reference to the pediatric population. Examples of MRI and MRA in the evaluation of the hepatic vasculature in pediatric patients are presented. (orig.)

  4. Advances of Transmission line kicker magnets

    CERN Document Server

    Ducimetière, Laurent

    2005-01-01

    Fast pulsed magnets or kickers are widely used in circular accelerators for injection, fast extraction and beam excitation. As from the early 60’s transmission line type kicker magnets have been employed to produce rectangular field pulses with good rise time. Over some 40 years this technology has evolved with the rising requirements. While the necessary kick strength has increased with the particle beam energy the strive for efficiency has pushed developments towards lower impedance systems and/or short circuited magnets. The flat top ripple is constrained by the maximally tolerable beam oscillation. The beam intensity can impose a screening of the magnet yoke. The most advanced features implemented in recent transmission line kicker magnets are reviewed and illustrated with examples from different laboratories.

  5. 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

  6. Using functional magnetic resonance imaging to improve how we understand, teach, and assess clinical reasoning

    NARCIS (Netherlands)

    Durning, S.J.; Costanzo, M.; Artino, A.R.; Vleuten, C.P.M. van der; Beckman, T.J.; Holmboe, E.; Roy, M.J.; Schuwirth, L.

    2014-01-01

    Clinical reasoning is essential to the practice of medicine. There have been many advances in the understanding of clinical reasoning and its assessment, yet current approaches have a number of important limitations. Functional magnetic resonance imaging (fMRI) is promising because it permits invest

  7. Research Applications of Magnetic Resonance Spectroscopy (MRS) to Investigate Psychiatric Disorders

    OpenAIRE

    Dager, SR; Oskin, NM; Richards, TL; Posse, S.

    2008-01-01

    Advances in magnetic resonance spectroscopy (MRS) methodology and related analytic strategies allow sophisticated testing of neurobiological models of disease pathology in psychiatric disorders. An overview of principles underlying MRS, methodological considerations and investigative approaches is presented. A review of recent research is presented that highlights innovative approaches applying MRS, in particular 1H MRS, to systematically investigate specific psychiatric disorders, including ...

  8. Magnetic Resonance Force Microscopy Quantum Computer with Tellurium Donors in Silicon

    International Nuclear Information System (INIS)

    We propose a magnetic resonance force microscopy (MRFM)-based nuclear spin quantum computer using tellurium impurities in silicon. This approach to quantum computing combines well-developed silicon technology and expected advances in MRFM. Our proposal does not use electrostatic gates to realize quantum logic operations

  9. Medical Imaging Field of Magnetic Resonance Imaging: Identification of Specialties within the Field

    Science.gov (United States)

    Grey, Michael L.

    2009-01-01

    This study was conducted to determine if specialty areas are emerging in the magnetic resonance imaging (MRI) profession due to advancements made in the medical sciences, imaging technology, and clinical applications used in MRI that would require new developments in education/training programs and national registry examinations. In this…

  10. Magnetic resonance imaging of the bowel. Today and tomorrow; Magnetresonanztomografie des Darms. Altbewaehrtes und Innovatives

    Energy Technology Data Exchange (ETDEWEB)

    Kinner, S.; Hahnemann, M.L.; Forsting, M.; Lauenstein, T.C. [Univ. Hospital Essen (Germany). Dept. of Diagnostic and Interventional Radiology and Neuroradiology

    2015-03-15

    Magnetic resonance imaging of the small bowel has been feasible for more than 15 years. This review is meant to give an overview of typical techniques, sequences and indications. Furthermore, newly evaluated promising techniques are presented, which have an impact on the advance of MR imaging of the small and large bowel.

  11. Magnetic resonance imaging of the cirrhotic liver: Anupdate

    Institute of Scientific and Technical Information of China (English)

    Agnes Watanabe; Miguel Ramalho; Mamdoh AlObaidy; Hye Jin Kim; Fernanda G Velloni; Richard C Semelka

    2015-01-01

    Noninvasive imaging has become the standard forhepatocellular carcinoma (HCC) diagnosis in cirrhoticlivers. In this review paper, we go over the basics ofMR imaging in cirrhotic livers and describe the imagingappearance of a spectrum of hepatic nodules markingthe progression from regenerative nodules to low- andhigh-grade dysplastic nodules, and ultimately to HCCs.We detail and illustrate the typical imaging appearancesof different types of HCC including focal, multifocal,massive, diffuse/infiltrative, and intra-hepaticmetastases; with emphasis on the diagnostic value ofMR in imaging these lesions. We also shed some lighton liver imaging reporting and data system, and therole of different magnetic resonance imaging (MRI)contrast agents and future MRI techniques includingthe use of advanced MR pulse sequences and utilizationof hepatocyte-specific MRI contrast agents, and howthey might contribute to improving the diagnosticperformance of MRI in early stage HCC diagnosis.

  12. Signal Improvement and Contrast Enhancement in Magnetic Resonance Imaging

    CERN Document Server

    Han, Yi

    2015-01-01

    This thesis reports advances in magnetic resonance imaging (MRI), with the ultimate goal of improving signal and contrast in biomedical applications. More specifically, novel MRI pulse sequences have been designed to characterize microstructure, enhance signal and contrast in tissue, and image functional processes. In this thesis, rat brain and red bone marrow images are acquired using iMQCs (intermolecular multiple quantum coherences) between intermediate separated spins. As an important application, iMQCs images in different directions can be used for anisotropy mapping and tissue microstructure analysis. At the same time, the simulations prove that the dipolar field from the overall shape only has small contributions to the experimental iMQC signal. Besides magnitude of iMQCs, phase of iMQCs should be studied as well. The phase anisotropy maps built by our method can clearly show susceptibility information in rat brain. It may provide meaningful diagnostic information. To deeply study susceptibility, the m...

  13. Magnetic resonance imaging abnormalities in multiple sclerosis: A review

    International Nuclear Information System (INIS)

    :During the last two decades, magnetic resonance imaging has been widely used In the diagnosis and treatment monitoring of multiple sclerosis. MRI, both conventional and non conventional methods, has transformed all aspects of M S research and clinical practice in recent years. Although advanced imaging methods have added much more to our knowledge about pathogenesis and natural history of the disease but their cost, availability, complexity and lack of validation have limited their use in routine clinical practice. Conventional MR techniques including proton density, T1/T2-Weighted images and fluid- attenuated inversion recovery sequences are now accepted in standard protocols for diagnosis and treatment outcome measures in clinical trials of multiple sclerosis. This review will focus on the type, morphology and evolution of M S lesions regarding conventional MRI and their use for treatment monitoring in daily clinical practice

  14. 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...

  15. Magnetic resonance imaging of spinal disorders

    International Nuclear Information System (INIS)

    The usefulness of magnetic resonance imaging (MRI) in the diagnosis of various spinal disorders was studied. Six normal volunteers and 19 patients with various spinal disorders were examined with a prototype MRI (Shimadzu Corp., Japan) operated with a 0.5-tesla superconducting magnet. The appropriate selection of both pulse sequences and detector coils were important factors in obtaining the best MRIs in spinal disorders. Short spin-echo (SE) images, a 0.3-sec repetition time (TR), and a 25-msec echo time (TE) provided the best anatomical details with a short scan time. Therefore, this pulse sequence was used at first in order to find the lesion roughly in all patients. Long SE images, 1.5-2 sec TR and 90-120 msec TE, then provided the details of the cerebro-spinal fluid (CSF) and the normal nucleus pulposus. This pulse sequence was used just as in a contrast myelogram in order to demonstrate the distortion of the subarachnoid space in such cases as tumors, canal stenosis, and herniated discs. The long SE image was also used to evaluate the degeneration of the intervertebral disc. Inversion recovery (IR) images did not provide more information than did SE images, because they could not differentiate the gray matter and the white matter in the spinal cord, unlike as in the brain. However, these IR images were used for delineating the tumor tissue from the normal spinal cord as well as for making the calculated T1 images. T1 images were calculated from the SE and IR images. T2 images were calculated from two SE images with different TEs. Both T1 and T2 images provided the details of the CSF and the proton-relaxation times in each tissue. It is supposed that the long SE, T1 and T2 images act as MRI myelograms, which demonstrate the CSF space well without a contrast medium. (J.P.N.)

  16. Surface Plasmon Resonance Biosensors: Advances and Applications

    Czech Academy of Sciences Publication Activity Database

    Homola, Jiří

    Vol. 7503. Bellingham, Washington: SPIE, 2009 - (Jones, J.; Culshaw, B.; Ecke, W.; López-Higuera, J.; Willsch, R.), 75030P-1-75030P-4 ISBN 9780819478146. ISSN 0277-786X. [20th International Conference on Optical Fibre Sensors. Edinburgh (GB), 05.10.2009-09.10.2009] R&D Projects: GA AV ČR KAN200670701; GA MŠk OC09058 Institutional research plan: CEZ:AV0Z20670512 Keywords : Plasmonics * Biosensor * Surface plasmon resonance Subject RIV: JB - Sensors, Measurment, Regulation

  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. Effects of magnetic coupling of nonadjacent resonators on wireless power domino-resonator systems

    OpenAIRE

    Zhong, WX; Hui, SYR; Lee, CK

    2012-01-01

    In this paper, the effects of the magnetic coupling of nonadjacent resonators on the optimal frequency of wireless power transfer are addressed. A power analysis has been carried out to identify the adjacent and nonadjacent power flow components. It is found that such cross-coupling effects of nonadjacent resonators would cause the maximum efficiency operation to slightly shift away from the resonance frequency of the resonators. Theoretical reasons for such phenomena are provided and experim...

  19. Magnetic resonance in prenatal diagnosis of thoracic anomalies

    International Nuclear Information System (INIS)

    The objective of this article is to communicate the experience in the evaluation of fetal anomalies thoracic by means of magnetic resonance. Between January, 2001 - March, 2007 16 fetus were evaluated by means of magnetic resonance with echographic diagnosis of thoracic anomalies. An equipment of 1.5 TESLA was used. The thoracic anatomy was valued in general. At the presence of discovering pulmonary mass, their size, volume and intensity of sign were determined. The echographic and magnetic resonance findings were checked against the perinatal results

  20. Magnetic resonance imaging for detecting prostate cancer

    International Nuclear Information System (INIS)

    Magnetic resonance imaging (MRI) plays an important role in the diagnosis of prostate cancer. However, some difficulties still exist. We retrospectively studied the pathohistological accuracy of MRI, comparing with that of transrectal ultrasonography (TRUS). We used AIRIS on a 0.3 tesla MRI unit with a body coil. 50 cases (prostate cancer: 30, BPH: 20) histologically diagnosed by sextant biopsy were studied. The accuracy of clinical diagnosis in MRI and TRUS were 76% and 72%, respectively. There is no significant difference. The prostate cancer in the peripheral zone was previously reported being as a low signal intensity on the T2 weighted image. But in the present study, over 85% of the cases did not revealed so-called typical appearance. There was no advantage clarified in diagnosing prostate cancer using MRI over TRUS. There is a certain limit to MRI in diagnosing prostatic cancer. But considering its ability of three-dimensional analysis, evaluating organs locally and generally, and MRI will be more advantageous. (author)

  1. 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.

  2. 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

  3. The diabetic foot: Magnetic resonance imaging evaluation

    International Nuclear Information System (INIS)

    Fourteen diabetic patients with suspected foot infection and/or neuropathic joint (Charcot Joint) were evaluated with magnetic resonance imaging (MRI) in an attempt to assess the extent of the infection and also to distinguish infection from the changes seen with neuroarthropathy. The majority of patients with infection had more than one site of involvement and the following diagnoses were made by MRI evaluation: Osteomyelitis (n=8), abscess (n=7), neuropathic joint (n=5), septic arthritis (n=4), and tenosynovitis (n=4). Clinical or surgical/pathological confirmation of the MRI diagnoses was obtained in all but nine sites of infection or cases of neuropathic joint. If the two diagnostic categories of septic arthritis and tenosynovitis are excluded, all but four of the MRI diagnoses were confirmed. A distinctive pattern for neuroarthropathy was identified in five cases, consisting of low signal intensity on T1- and T2-weighted images within the bone marrow space adjacent to the involved joint. We conclude that MRI is a valuable adjunct in the evaluation of the diabetic foot, and that it provides accurate information regarding the presence and extent of infection in this subset of patients. MRI has proven particularly helpful in differentiating neuroarthropathy from osteomyelitis. (orig.)

  4. 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.

  5. 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

  6. Magnetic resonance imaging of intracavernous pathology

    International Nuclear Information System (INIS)

    To evaluate the usefulness of magnetic resonance (MR) imaging of intracavernous pathology, T1-weighted spin echo images of four vascular lesions and 10 neoplastic lesions with surgically confirmed cavernous sinus (CS) invasion were reviewed retrospectively. In one case of traumatic carotid-cavernous fistula (CCF) and one of dural arteriovenous malformation (AVM), the internal carotid artery (ICA) and rapid shunted flow were depicted as signal voids, and the relationship between the ICA and shunted flow was clearly shown. Normal venous flow appeared as a low-intensity area and was observed even in the presence of the CCF and dural AVM. In two cases of thrombosed aneurysms, the thrombosis was clearly demonstrated, along with patent arterial flow in one case; in the other case, however, it was impossible to differentiate patent arterial flow from calcification. The intensity of all neoplastic lesions was similar to that of the cerebral cortex. The relationship between the ICA and the tumors was clearly demonstrated. The visual pathways were also plainly shown unless they were involved, or markedly compressed, by tumor. CS invasion was strongly associated with four findings: 1) encasement of the ICA by the tumor; 2) marked displacement of the ICA; 3) absence of low intensity, which reflects normal venous flow, in the CS; and 4) extension of extrasellar tumors to the medial wall or of intrasellar tumors to the lateral wall. MR imaging was judged promising in the evaluation of intracavernous pathology. (author)

  7. Magnetic resonance imaging of the cavernous sinus

    Energy Technology Data Exchange (ETDEWEB)

    Komiyama, Masaki (Baba Memorial Hospital, Osaka (Japan))

    1990-08-01

    The magnetic resonance (MR) appearance of the cavernous sinus (CS) was studied in 10 normal and 23 abnormal CSs (11 vascular and 12 neoplastic lesions) using T{sub 1}-wighted spin echo images with and without Gd-DTPA. In normal CSs, the intracavernous carotid artery (ICA) was disclosed as an area of signal void that was not enhanced with Gd-DTPA. Most venous flow showed low intensity and was markedly enhanced with Gd-DTPA. Venous flow, however, was heterogeneous, which suggested the distribution of flow velocities. In the carotid-cavernous sinus fistulas (CCFs), the ICA and shunted flow were disclosed as areas of signal void and their relationship was clearly shown. Normal venous flow appeared as a low intensity area even with CCFs. In the cavernous aneurysms, thrombosis and patent arterial flow were shown, but in one case it was impossible to differentiate patent arterial flow from calcification. In neoplastic lesions, CS invasion was suspected by encasement or marked dislocation of the ICA, disappearance of venous flow, and extension of extrasellar tumors to the medial wall and extension of sellar tumors to the lateral wall. MR was found to be a promising diagnostic modality for the evaluation of the CS. (author).

  8. Magnetic resonance imaging of intracavernous pathology

    Energy Technology Data Exchange (ETDEWEB)

    Komiyama, Masaki; Yasui, Toshihiro; Yagura, Hisatsugu; Fu, Yoshihiko; Baba, Mitsuru (Baba Memorial Hospital, Sakai, Osaka (Japan)); Hakuba, Akira; Nishimura, Shuro

    1989-07-01

    To evaluate the usefulness of magnetic resonance (MR) imaging of intracavernous pathology, T{sub 1}-weighted spin echo images of four vascular lesions and 10 neoplastic lesions with surgically confirmed cavernous sinus (CS) invasion were reviewed retrospectively. In one case of traumatic carotid-cavernous fistula (CCF) and one of dural arteriovenous malformation (AVM), the internal carotid artery (ICA) and rapid shunted flow were depicted as signal voids, and the relationship between the ICA and shunted flow was clearly shown. Normal venous flow appeared as a low-intensity area and was observed even in the presence of the CCF and dural AVM. In two cases of thrombosed aneurysms, the thrombosis was clearly demonstrated, along with patent arterial flow in one case; in the other case, however, it was impossible to differentiate patent arterial flow from calcification. The intensity of all neoplastic lesions was similar to that of the cerebral cortex. The relationship between the ICA and the tumors was clearly demonstrated. The visual pathways were also plainly shown unless they were involved, or markedly compressed, by tumor. CS invasion was strongly associated with four findings: (1) encasement of the ICA by the tumor; (2) marked displacement of the ICA; (3) absence of low intensity, which reflects normal venous flow, in the CS; and (4) extension of extrasellar tumors to the medial wall or of intrasellar tumors to the lateral wall. MR imaging was judged promising in the evaluation of intracavernous pathology. (author).

  9. Magnetic resonance imaging of the cavernous sinus

    International Nuclear Information System (INIS)

    The magnetic resonance (MR) appearance of the cavernous sinus (CS) was studied in 10 normal and 23 abnormal CSs (11 vascular and 12 neoplastic lesions) using T1-wighted spin echo images with and without Gd-DTPA. In normal CSs, the intracavernous carotid artery (ICA) was disclosed as an area of signal void that was not enhanced with Gd-DTPA. Most venous flow showed low intensity and was markedly enhanced with Gd-DTPA. Venous flow, however, was heterogeneous, which suggested the distribution of flow velocities. In the carotid-cavernous sinus fistulas (CCFs), the ICA and shunted flow were disclosed as areas of signal void and their relationship was clearly shown. Normal venous flow appeared as a low intensity area even with CCFs. In the cavernous aneurysms, thrombosis and patent arterial flow were shown, but in one case it was impossible to differentiate patent arterial flow from calcification. In neoplastic lesions, CS invasion was suspected by encasement or marked dislocation of the ICA, disappearance of venous flow, and extension of extrasellar tumors to the medial wall and extension of sellar tumors to the lateral wall. MR was found to be a promising diagnostic modality for the evaluation of the CS. (author)

  10. Monitoring angiogenesis using magnetic resonance methods

    DEFF Research Database (Denmark)

    Holm, David Alberg

    2008-01-01

    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 a...... in a transgenic mouse model. The last manuscript presents a new method for in vivo cell labeling. This method could find use in studying the metastatic spread of cancer cells throughout the body....... 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......-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...

  11. Magnetic resonance imaging of the larynx

    International Nuclear Information System (INIS)

    Larynx and hypopharynx represent difficult anatomical structures to evaluate by imaging. Pathological processes inflammatory conditions and neoplasms are frequently found specially neoplasms. The most common tumor originating in this region is squamous cell carcinoma that represents 90%, of malignancies, magnetic Resonance Imaging (MRI) is used for staging of those tumors. In our study we evaluate the technique used for MRI studies as well as the anatomy of the larynx, hypopharynx and nodes and the different classification system used for neck nodes. We also analyze the different types of neoplasm that can be found being and malignant and the use of MRI for staging neoplasms. Clinical and laryngoscope staging of laryngeal tumors is not accurate if fails to demonstrate deep submucosal and laryngeal spaces invasion (pre-epi glottic. para laryngeal, para glottic, anterior commissures posterior commissure and sub glottis) as well as cartilage infiltration and extra laryngeal extension. We need accurate imaging diagnostic methods like MRI to evaluate the extension of tumors. (Author) 38 refs

  12. Magnetic resonance tomography in confirmed multiple sclerosis

    International Nuclear Information System (INIS)

    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 lesons 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. (orig.)

  13. 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

  14. 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

  15. 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.

  16. 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.)

  17. Nuclear magnetic resonance studies of metabolic regulation

    International Nuclear Information System (INIS)

    Nuclear magnetic resonance (NMR) techniques for the detection of the metabolic transformations of biological compounds labeled with stable isotopes, particularly carbon-13 have been explored. We have studied adipose tissue in the intact rat, the exteriorized epididymal fat pad, and the isolated adipocyte. Triacylglycerol metabolism in adipose tissue is regulated by lipogenic factors (insulin, corticosterone, thyroxine, and growth hormone) and lipolytic factors (glucagon and catecholamines). The synthesis of triglyceride from 5.5 mM glucose was stimulated by about 4-fold by 10 nM insulin. Triglyceride synthesis from glucose in the presence of insulin occurred at a rate of 330 nmol/hr/106 cells. Since the NMR signals from free and esterified fatty acids and glycerol are distinct, we could directly measure the rate of hormone-stimulated lipolysis. Epinephrine (10 μM) gave a lipolytic rate of 0.30 μmol/hr/106 cells as monitored by free-glycerol appearance in the medium. 13C NMR provides a superior method for the measurement of triglyceride metabolism since it directly measures the changes in the substrates and products in situ

  18. Magnetic Resonance Imaging Features of Neuromyelitis Optica

    International Nuclear Information System (INIS)

    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.

  19. 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)

  20. Magnetic resonance imaging of the adrenal gland

    International Nuclear Information System (INIS)

    Adrenal imaging was performed using magnetic resonance (MR) was in 100 patients who had no clinical or biochemical evidence of adrenal abnormality and in 19 patients with 24 adrenal lesions (adenoma in 5, hyperplasia in 2, metastasis in 5 (lung cancer in 1, hepatoma in 4), adrenal cancer in 1, pheochromocytoma in 3, neuroblastoma in 3). Normal adrenal glands showed intermediate intensity between muscle and liver, and were detected in over 90% of cases on T1-weighted images (T1-weighted SE, inversion recovery). Adenomas and hyperplasias had the same intensity as normal glands. Medullary masses showed extreme hyperintensity on T2-weighted images and could be differentiated from cortical masses. Neuroblastomas were detected as hyperintense tumors with intratumoral hemorrhage and necrosis on T2-weighted images. Metastatic adrenal tumors from lung cancer were hyperintense on T2-weighted images, while metastasis from hepatoma showed low intensity on the same pulse sequence. In diagnosing adrenal metastasis, we must compare and contrast the tumor intensity and structure with those of the primary lesions. MR is considered a useful modality in characterizing adrenal tissue. (author)