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Sample records for magnetic resonance analysis

  1. Quantitative analysis by nuclear magnetic resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Wainai, T; Mashimo, K [Nihon Univ., Tokyo. Coll. of Science and Engineering

    1976-04-01

    Recent papers on the practical quantitative analysis by nuclear magnetic resonance spectroscopy (NMR) are reviewed. Specifically, the determination of moisture in liquid N/sub 2/O/sub 4/ as an oxidizing agent for rocket propulsion, the analysis of hydroperoxides, the quantitative analysis using a shift reagent, the analysis of aromatic sulfonates, and the determination of acids and bases are reviewed. Attention is paid to the accuracy. The sweeping velocity and RF level in addition to the other factors must be on the optimal condition to eliminate the errors, particularly when computation is made with a machine. Higher sweeping velocity is preferable in view of S/N ratio, but it may be limited to 30 Hz/s. The relative error in the measurement of area is generally 1%, but when those of dilute concentration and integrated, the error will become smaller by one digit. If impurities are treated carefully, the water content on N/sub 2/O/sub 4/ can be determined with accuracy of about 0.002%. The comparison method between peak heights is as accurate as that between areas, when the uniformity of magnetic field and T/sub 2/ are not questionable. In the case of chemical shift movable due to content, the substance can be determined by the position of the chemical shift. Oil and water contents in rape-seed, peanuts, and sunflower-seed are determined by measuring T/sub 1/ with 90 deg pulses.

  2. Analysis and Modeling of Integrated Magnetics for LLC resonant Converters

    DEFF Research Database (Denmark)

    Li, Mingxiao; Ouyang, Ziwei; Zhao, Bin

    2017-01-01

    Shunt-inserted transformers are widely used toobtain high leakage inductance. This paper investigates thismethod in depth to make it applicable to integrate resonantinductor for the LLC resonant converters. The analysis andmodel of magnetizing inductance and leakage inductance forshunt...... transformers can provide a significantdifference. The way to obtain the desirable magnetizing andleakage inductance value for LLC resonant converters issimplified by the creation of air gaps together with a magneticshunt. The calculation and relation are validated by finiteelement analysis (FEA) simulations...

  3. Comparative analysis of nuclear magnetic resonance well logging and nuclear magnetic resonance mud logging

    International Nuclear Information System (INIS)

    Yuan Zugui

    2008-01-01

    The hydrogen atoms in oil and water are able to resonate and generate signals in the magnetic field, which is used by the NMR (nuclear magnetic resonance) technology in petroleum engineering to research and evaluate rock characteristics. NMR well logging was used to measure the physical property parameters of the strata in well bore, whereas NMR mud logging was used to analyze (while drilling) the physical property parameters of cores, cuttings and sidewall coring samples on surface (drilling site). Based on the comparative analysis of the porosity and permeability parameters obtained by NMR well logging and those from analysis of the cores, cuttings and sidewall coring samples by NMR mud logging in the same depth of 13 wells, these two methods are of certain difference, but their integral tendency is relatively good. (authors)

  4. Magnetic Resonance Force Microscopy System

    Data.gov (United States)

    Federal Laboratory Consortium — The Magnetic Resonance Force Microscopy (MRFM) system, developed by ARL, is the world's most sensitive nuclear magnetic resonance (NMR) spectroscopic analysis tool,...

  5. Magnetic resonance annual 1986

    International Nuclear Information System (INIS)

    Kressel, H.Y.

    1986-01-01

    This book contains papers written on magnetic resonance during 1986. Topics include: musculosketetal magnetic resonance imaging; imaging of the spine; magnetic resonance chemical shift imaging; magnetic resonance imaging in the central nervous system; comparison to computed tomography; high resolution magnetic resonance imaging using surface coils; magnetic resonance imaging of the chest; magnetic resonance imaging of the breast; magnetic resonance imaging of the liver; magnetic resonance spectroscopy of neoplasms; blood flow effects in magnetic resonance imaging; and current and potential applications of clinical sodium magnetic resonance imaging

  6. Methods for magnetic resonance analysis using magic angle technique

    Science.gov (United States)

    Hu, Jian Zhi [Richland, WA; Wind, Robert A [Kennewick, WA; Minard, Kevin R [Kennewick, WA; Majors, Paul D [Kennewick, WA

    2011-11-22

    Methods of performing a magnetic resonance analysis of a biological object are disclosed that include placing the object in a main magnetic field (that has a static field direction) and in a radio frequency field; rotating the object at a frequency of less than about 100 Hz around an axis positioned at an angle of about 54.degree.44' relative to the main magnetic static field direction; pulsing the radio frequency to provide a sequence that includes a phase-corrected magic angle turning pulse segment; and collecting data generated by the pulsed radio frequency. In particular embodiments the method includes pulsing the radio frequency to provide at least two of a spatially selective read pulse, a spatially selective phase pulse, and a spatially selective storage pulse. Further disclosed methods provide pulse sequences that provide extended imaging capabilities, such as chemical shift imaging or multiple-voxel data acquisition.

  7. 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 Linkedin Pin it Email Print Magnetic Resonance Imaging (MRI) is a medical imaging procedure for ...

  8. Analysis of Gradient Waveform in Magnetic Resonance Imaging

    Directory of Open Access Journals (Sweden)

    OU-YANG Shan-mei

    2017-12-01

    Full Text Available The accuracy of gradient pulse waveform affects image quality significantly in magnetic resonance imaging (MRI. Recording and analyzing the waveform of gradient pulse helps to make rapid and accurate diagnosis of spectrometer gradient hardware and/or pulse sequence. Using the virtual instrument software LabVIEW to control the high speed data acquisition card DAQ-2005, a multi-channel acquisition scheme was designed to collect the gradient outputs from a custom-made spectrometer. The collected waveforms were post-processed (i.e., histogram statistical analysis, data filtering and difference calculation to obtain feature points containing time and amplitude information. Experiments were carried out to validate the method, which is an auxiliary test method for the development of spectrometer and pulses sequence.

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

    Science.gov (United States)

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

    1992-01-01

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

  10. Novel axolotl cardiac function analysis method using magnetic resonance imaging.

    Directory of Open Access Journals (Sweden)

    Pedro Gomes Sanches

    Full Text Available The salamander axolotl is capable of complete regeneration of amputated heart tissue. However, non-invasive imaging tools for assessing its cardiac function were so far not employed. In this study, cardiac magnetic resonance imaging is introduced as a non-invasive technique to image heart function of axolotls. Three axolotls were imaged with magnetic resonance imaging using a retrospectively gated Fast Low Angle Shot cine sequence. Within one scanning session the axolotl heart was imaged three times in all planes, consecutively. Heart rate, ejection fraction, stroke volume and cardiac output were calculated using three techniques: (1 combined long-axis, (2 short-axis series, and (3 ultrasound (control for heart rate only. All values are presented as mean ± standard deviation. Heart rate (beats per minute among different animals was 32.2±6.0 (long axis, 30.4±5.5 (short axis and 32.7±4.9 (ultrasound and statistically similar regardless of the imaging method (p > 0.05. Ejection fraction (% was 59.6±10.8 (long axis and 48.1±11.3 (short axis and it differed significantly (p = 0.019. Stroke volume (μl/beat was 133.7±33.7 (long axis and 93.2±31.2 (short axis, also differed significantly (p = 0.015. Calculations were consistent among the animals and over three repeated measurements. The heart rate varied depending on depth of anaesthesia. We described a new method for defining and imaging the anatomical planes of the axolotl heart and propose one of our techniques (long axis analysis may prove useful in defining cardiac function in regenerating axolotl hearts.

  11. Analysis of ringing effects due to magnetic core materials in pulsed nuclear magnetic resonance circuits

    International Nuclear Information System (INIS)

    Prabhu Gaunkar, N.; Bouda, N. R. Y.; Nlebedim, I. C.; Hadimani, R. L.; Mina, M.; Jiles, D. C.; Bulu, I.; Ganesan, K.; Song, Y. Q.

    2015-01-01

    This work presents investigations and detailed analysis of ringing in a non-resonant pulsed nuclear magnetic resonance (NMR) circuit. Ringing is a commonly observed phenomenon in high power switching circuits. The oscillations described as ringing impede measurements in pulsed NMR systems. It is therefore desirable that those oscillations decay fast. It is often assumed that one of the causes behind ringing is the role of the magnetic core used in the antenna (acting as an inductive load). We will demonstrate that an LRC subcircuit is also set-up due to the inductive load and needs to be considered due to its parasitic effects. It is observed that the parasitics associated with the inductive load become important at certain frequencies. The output response can be related to the response of an under-damped circuit and to the magnetic core material. This research work demonstrates and discusses ways of controlling ringing by considering interrelationships between different contributing factors

  12. Analysis of ringing effects due to magnetic core materials in pulsed nuclear magnetic resonance circuits

    Energy Technology Data Exchange (ETDEWEB)

    Prabhu Gaunkar, N., E-mail: neelampg@iastate.edu; Bouda, N. R. Y.; Nlebedim, I. C.; Hadimani, R. L.; Mina, M.; Jiles, D. C. [Department of Electrical and Computer Engineering, Iowa State University, Ames, Iowa 50011 (United States); Bulu, I.; Ganesan, K.; Song, Y. Q. [Schlumberger-Doll Research, Cambridge, Massachusetts 02139 (United States)

    2015-05-07

    This work presents investigations and detailed analysis of ringing in a non-resonant pulsed nuclear magnetic resonance (NMR) circuit. Ringing is a commonly observed phenomenon in high power switching circuits. The oscillations described as ringing impede measurements in pulsed NMR systems. It is therefore desirable that those oscillations decay fast. It is often assumed that one of the causes behind ringing is the role of the magnetic core used in the antenna (acting as an inductive load). We will demonstrate that an LRC subcircuit is also set-up due to the inductive load and needs to be considered due to its parasitic effects. It is observed that the parasitics associated with the inductive load become important at certain frequencies. The output response can be related to the response of an under-damped circuit and to the magnetic core material. This research work demonstrates and discusses ways of controlling ringing by considering interrelationships between different contributing factors.

  13. Novel axolotl cardiac function analysis method using magnetic resonance imaging

    NARCIS (Netherlands)

    Sanches, Pedro Gomes; Op 't Veld, Roel C.; de Graaf, Wolter; Strijkers, Gustav J.; Grüll, Holger

    2017-01-01

    The salamander axolotl is capable of complete regeneration of amputated heart tissue. However, non-invasive imaging tools for assessing its cardiac function were so far not employed. In this study, cardiac magnetic resonance imaging is introduced as a non-invasive technique to image heart function

  14. Novel axolotl cardiac function analysis method using magnetic resonance imaging

    NARCIS (Netherlands)

    Sanches, P.G.; Op ‘t Veld, R.C.; de Graaf, W.; Strijkers, G.J.; Grüll, H.

    2017-01-01

    The salamander axolotl is capable of complete regeneration of amputated heart tissue. However, non-invasive imaging tools for assessing its cardiac function were so far not employed. In this study, cardiac magnetic resonance imaging is introduced as a noninvasive technique to image heart function of

  15. Analysis with magnetic resonance imaging of lesions in cerebral achromatopsia

    International Nuclear Information System (INIS)

    Tanaka, Yuichiro; Kitahara, Kenji; Kumegawa, Koichi; Umahara, Takahiko

    2002-01-01

    The purpose of this study was to localize the lesions associated with cerebral achromatopsia. We examined 20 patients with homonymous hemianopsia caused by cerebral infarction (17 men and 3 women aged 49 to 81 years; mean age, 65.1 years). Ishihara plates, standard pseudoiso-chromatic plates (part 2) and the panel D-15 test were used to examine color perception. Color matching tasks and color naming tasks were used to test color recognition. We tried to apply functional magnetic resonance imaging (fMRI) to lesion analysis in the brain. Cerebral achromatopsia was diagnosed in four patients. The analysis showed that lesions in the infracalcarine area (Brodmann's area 18 and 19) were associated with cerebral achromatopsia. Additionally, the lesions associated with failure of the panel D-15 (PD-15) test were located more anterior than the lesions associated with failure of Ishihara plates. We show evidence that lesions in the anterio-ventral temporo-occipital area are associated with cerebral achromatopsia. This result is in accord with past observations (autopsy, fMRI and positron emission tomography). (author)

  16. Automated analysis of craniofacial morphology using magnetic resonance images.

    Directory of Open Access Journals (Sweden)

    M Mallar Chakravarty

    Full Text Available Quantitative analysis of craniofacial morphology is of interest to scholars working in a wide variety of disciplines, such as anthropology, developmental biology, and medicine. T1-weighted (anatomical magnetic resonance images (MRI provide excellent contrast between soft tissues. Given its three-dimensional nature, MRI represents an ideal imaging modality for the analysis of craniofacial structure in living individuals. Here we describe how T1-weighted MR images, acquired to examine brain anatomy, can also be used to analyze facial features. Using a sample of typically developing adolescents from the Saguenay Youth Study (N = 597; 292 male, 305 female, ages: 12 to 18 years, we quantified inter-individual variations in craniofacial structure in two ways. First, we adapted existing nonlinear registration-based morphological techniques to generate iteratively a group-wise population average of craniofacial features. The nonlinear transformations were used to map the craniofacial structure of each individual to the population average. Using voxel-wise measures of expansion and contraction, we then examined the effects of sex and age on inter-individual variations in facial features. Second, we employed a landmark-based approach to quantify variations in face surfaces. This approach involves: (a placing 56 landmarks (forehead, nose, lips, jaw-line, cheekbones, and eyes on a surface representation of the MRI-based group average; (b warping the landmarks to the individual faces using the inverse nonlinear transformation estimated for each person; and (3 using a principal components analysis (PCA of the warped landmarks to identify facial features (i.e. clusters of landmarks that vary in our sample in a correlated fashion. As with the voxel-wise analysis of the deformation fields, we examined the effects of sex and age on the PCA-derived spatial relationships between facial features. Both methods demonstrated significant sexual dimorphism in

  17. Magnetic resonance imaging texture analysis classification of primary breast cancer

    International Nuclear Information System (INIS)

    Waugh, S.A.; Lerski, R.A.; Purdie, C.A.; Jordan, L.B.; Vinnicombe, S.; Martin, P.; Thompson, A.M.

    2016-01-01

    Patient-tailored treatments for breast cancer are based on histological and immunohistochemical (IHC) subtypes. Magnetic Resonance Imaging (MRI) texture analysis (TA) may be useful in non-invasive lesion subtype classification. Women with newly diagnosed primary breast cancer underwent pre-treatment dynamic contrast-enhanced breast MRI. TA was performed using co-occurrence matrix (COM) features, by creating a model on retrospective training data, then prospectively applying to a test set. Analyses were blinded to breast pathology. Subtype classifications were performed using a cross-validated k-nearest-neighbour (k = 3) technique, with accuracy relative to pathology assessed and receiver operator curve (AUROC) calculated. Mann-Whitney U and Kruskal-Wallis tests were used to assess raw entropy feature values. Histological subtype classifications were similar across training (n = 148 cancers) and test sets (n = 73 lesions) using all COM features (training: 75 %, AUROC = 0.816; test: 72.5 %, AUROC = 0.823). Entropy features were significantly different between lobular and ductal cancers (p < 0.001; Mann-Whitney U). IHC classifications using COM features were also similar for training and test data (training: 57.2 %, AUROC = 0.754; test: 57.0 %, AUROC = 0.750). Hormone receptor positive and negative cancers demonstrated significantly different entropy features. Entropy features alone were unable to create a robust classification model. Textural differences on contrast-enhanced MR images may reflect underlying lesion subtypes, which merits testing against treatment response. (orig.)

  18. Multivariate analysis of magnetic resonance imaging of focal hepatic lesions

    International Nuclear Information System (INIS)

    Fujishima, Mamoru; Suemitsu, Ichizou; Sei, Tetsurou; Takeda, Yoshihiro; Hiraki, Yoshio

    1993-01-01

    A total of 124 lesions from 1 to 6 cm in diameter, including 31 cavernous hemangiomas, 32 metastases and 61 hepatocellular carcinomas (HCC) were analyzed to study the usefulness of magnetic resonance imaging (MRI) at 0.5 Tesla to differentiate focal hepatic lesions on the basis of qualitative criteria. Each focal hepatic lesion was assessed for shape, internal architecture and signal intensity relative to normal liver parenchyma. While all cavernous hemangiomas and metastases except one lesion could be detected, detection rate of HCC was significantly inferior to that of the other two diseases. A tumor capsule and a hyperintense focus on T 1 -weighted images were demonstrated in only HCC lesions in strong contrast with the other two diseases; however, metastases with slow-growing characteristics or subacute hematoma may appear as similar images. Cavernous hemangiomas appeared markedly hyperintense on T 2 -weighted images in 23 of 31 lesions, but one metastasis and one HCC had similar images. A multivariate analysis of several MRI resulted in the following mean discriminant scores: cavernous hemangioma, -1.2652; metastasis, 0.1830; and HCC, 0.7138. It appeared to be possible to differentiate the three diseases with 84.4 percent accuracy. (author)

  19. Magnetic resonance imaging texture analysis classification of primary breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Waugh, S.A.; Lerski, R.A. [Ninewells Hospital and Medical School, Department of Medical Physics, Dundee (United Kingdom); Purdie, C.A.; Jordan, L.B. [Ninewells Hospital and Medical School, Department of Pathology, Dundee (United Kingdom); Vinnicombe, S. [University of Dundee, Division of Imaging and Technology, Ninewells Hospital and Medical School, Dundee (United Kingdom); Martin, P. [Ninewells Hospital and Medical School, Department of Clinical Radiology, Dundee (United Kingdom); Thompson, A.M. [University of Texas MD Anderson Cancer Center, Department of Surgical Oncology, Houston, TX (United States)

    2016-02-15

    Patient-tailored treatments for breast cancer are based on histological and immunohistochemical (IHC) subtypes. Magnetic Resonance Imaging (MRI) texture analysis (TA) may be useful in non-invasive lesion subtype classification. Women with newly diagnosed primary breast cancer underwent pre-treatment dynamic contrast-enhanced breast MRI. TA was performed using co-occurrence matrix (COM) features, by creating a model on retrospective training data, then prospectively applying to a test set. Analyses were blinded to breast pathology. Subtype classifications were performed using a cross-validated k-nearest-neighbour (k = 3) technique, with accuracy relative to pathology assessed and receiver operator curve (AUROC) calculated. Mann-Whitney U and Kruskal-Wallis tests were used to assess raw entropy feature values. Histological subtype classifications were similar across training (n = 148 cancers) and test sets (n = 73 lesions) using all COM features (training: 75 %, AUROC = 0.816; test: 72.5 %, AUROC = 0.823). Entropy features were significantly different between lobular and ductal cancers (p < 0.001; Mann-Whitney U). IHC classifications using COM features were also similar for training and test data (training: 57.2 %, AUROC = 0.754; test: 57.0 %, AUROC = 0.750). Hormone receptor positive and negative cancers demonstrated significantly different entropy features. Entropy features alone were unable to create a robust classification model. Textural differences on contrast-enhanced MR images may reflect underlying lesion subtypes, which merits testing against treatment response. (orig.)

  20. Magnetic resonance annual, 1988

    International Nuclear Information System (INIS)

    Kressel, H.Y.

    1987-01-01

    This book features reviews of high-resolution MRI of the knee, MRI of the normal and ischmeic hip, MRI of the heart, and temporomandibular joint imaging, as well as thorough discussion on artifacts in magnetic resonance imaging. Contributors consider the clinical applications of gadolinium-DTPA in magnetic resonance imaging and the clinical use of partial saturation and saturation recovery sequences. Timely reports assess the current status of rapid MRI and describe a new rapid gated cine MRI technique. Also included is an analysis of cerebrospinal fluid flow effects during MRI of the central nervous system

  1. Frequency-domain analysis of resonant-type ring magnet power supplies

    International Nuclear Information System (INIS)

    Kim, J.M.S.; Reiniger, K.W.

    1993-01-01

    For fast-cycling synchrotrons, resonant-type ring magnet power supplies are commonly used to provide a dc-biased ac excitation for the ring magnets. Up to the present, this power supply system has been analyzed using simplified analytical approximation, namely assuming the resonant frequency of the ring magnet network is fixed and equal to the accelerator frequency. This paper presents a frequency-domain analysis technique for a more accurate analysis of resonant-type ring magnet power supplies. This approach identifies that, with the variation of the resonant frequency, the operating conditions of the power supply changes quite dramatically because of the high Q value of the resonant network. The analytical results are verified, using both experimental results and simulation results

  2. The diagnostic accuracy of acetabular labral tears using magnetic resonance imaging and magnetic resonance arthrography: a meta-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Toby O. [University of East Anglia, Faculty of Health, Queen' s Building, Norwich (United Kingdom); Hilton, Gemma [Norfolk and Norwich University Hospital, Norwich (United Kingdom); Toms, Andoni P.; Donell, Simon T. [Norfolk and Norwich University Hospital, University of East Anglia, Norwich (United Kingdom); Hing, Caroline B. [St. George' s Hospital, London (United Kingdom)

    2011-04-15

    Magnetic resonance imaging (MRI) and magnetic resonance arthrography (MRA) have been advocated for the diagnosis of acetabular labral tears. The purpose of this study was to determine the sensitivity and specificity of MRI and MRA in diagnosing acetabular labral tears using meta-analysis. Pertinent published and unpublished literature databases were reviewed. A two-by-two table was constructed to calculate the sensitivity and specificity of MRI or MRA investigations against surgical outcomes. Pooled sensitivity and specificity and Receiver Operating Characteristic curve (ROC) evaluations were performed. Methodological quality of each study was assessed using the QUADAS (Quality Assessment of Diagnostic Accuracy Studies) tool. Nineteen papers assessing 881 hips were reviewed. Conventional MRI was assessed in 13 studies and MRA was assessed in 16 studies. Whilst both MRI (0.5-3T) and MRA (0.5-3T) presented with a moderate sensitivity and specificity (sensitivity 66%, 87%; specificity 79%, 64%), diagnostic accuracy of MRA appeared to be superior to MRI in detecting acetabular labral tears on ROC curve interpretation. The literature poorly described population characteristics, assessor blinding, with limited sample sizes. MRI and MRA may be useful adjuncts in the diagnosis of acetabular labral tears in adults. MRA appears to be superior to conventional MRI. (orig.)

  3. Pediatric magnetic resonance imaging

    International Nuclear Information System (INIS)

    Cohen, M.D.

    1986-01-01

    This book defines the current clinical potential of magnetic resonance imaging and focuses on direct clinical work with pediatric patients. A section dealing with the physics of magnetic resonance imaging provides an introduction to enable clinicians to utilize the machine and interpret the images. Magnetic resonance imaging is presented as an appropriate imaging modality for pediatric patients utilizing no radiation

  4. Magnetic resonance imaging apparatus

    International Nuclear Information System (INIS)

    Ehnholm, G.J.

    1991-01-01

    This patent describes an electron spin resonance enhanced magnetic resonance (MR) imaging (ESREMRI) apparatus able to generate a primary magnetic field during periods of nuclear spin transition excitation and magnetic resonance signal detection. This allows the generation of ESREMRI images of a subject. A primary magnetic field of a second and higher value generated during periods of nuclear spin transition excitation and magnetic resonance signal detection can be used to generate conventional MR images of a subject. The ESREMRI and native MR images so generated may be combined, (or superimposed). (author)

  5. Magnetic resonance imaging of myositis ossificans: Analysis of seven cases

    International Nuclear Information System (INIS)

    De Smet, A.A.; Norris, M.A.; Fisher, D.R.

    1992-01-01

    Since magnetic resonance imaging (MRI) is commonly used to evaluate soft tissue masses, we analyzed eight MR examinations in seven patients with myositis ossificans to determine if typical patterns were present. One acute lesion had homogeneous intermediate signal intensity on T1-weighted images and high signal intensity on T2-weighted images. Two subacute lesions had low signal intensity margins with slightly increased signal intensity centers on T1-weighted images and very high signal intensity on T2-weighted images. Five chronic lesions had two different patterns. All five were well-defined with low signal intensity borders. Three had signal intensity patterns characteristic of fat on T1-weighted and T2-weighted images. The other two lesions had intermediate signal intensity on T1-weighted images and slightly increased signal intensity on T2-weighted images. We conclude that typical MR appearances of myositis ossificans do exist. A low signal intensity rim is a common finding. However, these patterns are not unique to myositis ossificans and resemble those that have been reported in other lesions. It is important to be aware of the spectrum of MR findings of myositis ossificans when considering the differential diagnosis of a soft tissue mass. (orig./MG)

  6. Cardiac magnetic resonance imaging

    African Journals Online (AJOL)

    2011-03-06

    Mar 6, 2011 ... Cardiac magnetic resonance imaging. Cardiovascular magnetic resonance imaging is becoming a routine diagnostic technique. BRUCE s sPOTTiswOOdE, PhD. MRC/UCT Medical Imaging Research Unit, University of Cape Town, and Division of Radiology, Stellenbosch University. Bruce Spottiswoode ...

  7. Method for high resolution magnetic resonance analysis using magic angle technique

    Science.gov (United States)

    Wind, Robert A.; Hu, Jian Zhi

    2003-12-30

    A method of performing a magnetic resonance analysis of a biological object that includes placing the object in a main magnetic field (that has a static field direction) and in a radio frequency field; rotating the object at a frequency of less than about 100 Hz around an axis positioned at an angle of about 54.degree.44' relative to the main magnetic static field direction; pulsing the radio frequency to provide a sequence that includes a phase-corrected magic angle turning pulse segment; and collecting data generated by the pulsed radio frequency. The object may be reoriented about the magic angle axis between three predetermined positions that are related to each other by 120.degree.. The main magnetic field may be rotated mechanically or electronically. Methods for magnetic resonance imaging of the object are also described.

  8. Analysis and design of a coupled coaxial line TEM resonator for magnetic resonance imaging

    International Nuclear Information System (INIS)

    Benahmed, Nasreddine; Feham, Mohammed; Khelif, M'Hamed

    2006-01-01

    In this paper, we have successfully realized a numerical tool to analyse and to design an n-element unloaded coaxial line transverse electromagnetic (TEM) resonator. This numerical tool allows the determination of the primary parameters, matrices [L], [C] and [R], and simulates the frequency response of S 11 at the RF port of the designed TEM resonator. The frequency response permits evaluation of the unloaded quality factor Q 0 . As an application, we present the analysis and the design of an eight-element unloaded TEM resonator for animal studies at 4.7 T. The simulated performance has a -62.81 dB minimum reflection and a quality factor of 260 around 200 MHz

  9. Sensitivity analysis of magnetic field measurements for magnetic resonance electrical impedance tomography (MREIT)

    DEFF Research Database (Denmark)

    Göksu, Cihan; Scheffler, Klaus; Ehses, Philipp

    2017-01-01

    Purpose: Clinical use of magnetic resonance electrical impedance tomography (MREIT) still requires significant sensitivity improvements. Here, the measurement of the current-induced magnetic field (DBz,c) is improved using systematic efficiency analyses and optimization of multi-echo spin echo...... (MESE) and steady-state free precession free induction decay (SSFP-FID) sequences. Theory and Methods: Considering T1, T2, and T 2 relaxation in the signal-to-noise ratios (SNRs) of the MR magnitude images, the efficiency of MESE and SSFP-FID MREIT experiments, and its dependence on the sequence...

  10. Preliminary analysis of proton magnetic resonance 1D spectra of cerebrospinal fluid and brain cancer extracts

    International Nuclear Information System (INIS)

    Toczylowska, B.; Jozwik, A.; Kierul, K.; Matysiak, Z.; Sidor, M.; Wojcik, J.

    1999-01-01

    In series of cerebrospinal fluid samples from 25 patients proton spectra of magnetic resonance were measured. The spectra were measured also for series of brain tumor tissue extracts received from another 25 patients. This paper presents an attempt to apply statistical methods of image recognition for spectra analysis of the two measured series

  11. Nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Ethier, R.; Melanson, D.; Peters, T.M.

    1983-01-01

    Ten years following computerized tomography, a new technique called nuclear magnetic resonance revolutionizes the field of diagnostic imaging. A major advantage of nuclear magnetic resonance is that the danger of radiation is non-existent as compared to computerized tomography. When parts of the human body are subject to radio-frequencies while in a fixed magnetic field, its most detailed structures are revealed. The quality of images, the applications, as well as the indications are forever increasing. Images obtained at the level of the brain and spinal cord through nuclear magnetic resonance supercede those obtained through computerized tomography. Hence, it is most likely that myelography, along with pneumoencephalography will be eliminated as a diagnostic means. It is without a doubt that nuclear magnetic resonance is tomorrow's computerized tomography [fr

  12. The nuclear magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Goyer, Ph.

    1997-01-01

    The spectroscopy of nuclear magnetic resonance constitutes a major analytical technique in biological and organic analysis. This technique appears now in the programme of preparatory classes and its teaching is developed in the second year of DEUG. The following article reviews on the nuclear magnetic resonance and on the possibilities it offers to bring to the fore the physico-chemical properties of molecules. (N.C.)

  13. Magnetic Resonance (MR) Defecography

    Science.gov (United States)

    ... to a CD or uploaded to a digital cloud server. Magnetic resonance (MR) defecography is a special ... with you. top of page What are the benefits vs. risks? Benefits MR defecography helps assess pelvic ...

  14. Magnetic resonance angiography (MRA)

    International Nuclear Information System (INIS)

    Arlart, I.P.; Guhl, L.

    1992-01-01

    An account is given in this paper of the physical and technical principles underlying the 'time-of-flight' technique for imaging of vessels by magnetic resonance tomography. Major indications for the new procedure of magnetic resonance angiography at present are intracerebral and extracerebral vessels, with digital subtraction angiography quite often being required to cope with minor alterations (small aneurysms, small occlusions). Magnetic resonance angiography and digital subtraction angiography are compared to each other for advantages and disadvantages. Basically, replacement of radiological angiography by magnetic resonance angiography appears to be possible only within limits, since X-ray diagnostics primarily provides morphological information about vessels, whereas flow dynamics is visualized by the 'time-of-flight' technique. (orig.) [de

  15. Magnetic Resonance Cholangiopancreatography (MRCP)

    Science.gov (United States)

    ... radio waves and a computer to evaluate the liver, gallbladder, bile ducts, pancreas and pancreatic duct for disease. It is ... of the hepatobiliary and pancreatic systems, including the liver, gallbladder, bile ducts, pancreas and pancreatic duct . Magnetic resonance imaging (MRI) ...

  16. Magnetic Resonance Sensors

    Directory of Open Access Journals (Sweden)

    Robert H. Morris

    2014-11-01

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

  17. Magnetic resonance angiography

    Science.gov (United States)

    ... Saunders; 2015:chap 17. Litt H, Carpenter JP. Magnetic resonance imaging. In: Cronenwett JL, Johnston KW, eds. Rutherford's Vascular Surgery . 8th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap ...

  18. Magnetic resonance imaging

    International Nuclear Information System (INIS)

    Robertson, Angus

    1990-01-01

    An assessment is made of the clinical benefits of expensive diagnostic technology, such as the magnetic resonance imaging. It is concluded that to most radiologists, magnetic resonance imaging has a definite place in the diagnostic scenario, especially for demonstrating central nervous system lesions in multiple sclerosis. While it is recognized that medical and financial resources are limited, it is emphasised that the cost to society must be balanced against the patient benefit. 17 refs

  19. Nuclear magnetic resonance gyroscope

    International Nuclear Information System (INIS)

    Grover, B.C.

    1984-01-01

    A nuclear magnetic resonance gyro using two nuclear magnetic resonance gases, preferably xenon 129 and xenon 131, together with two alkaline metal vapors, preferably rubidium, potassium or cesium, one of the two alkaline metal vapors being pumped by light which has the wavelength of that alkaline metal vapor, and the other alkaline vapor being illuminated by light which has the wavelength of that other alkaline vapor

  20. Nuclear magnetic resonance imaging

    International Nuclear Information System (INIS)

    Young, I.R.

    1984-01-01

    In a method of imaging a body in which nuclear magnetic resonance is excited in a region including part of the body, and the free induction decay signal is measured, a known quantity of a material of known nuclear magnetic resonance properties, for example a bag of water, is included in the region so as to enhance the measured free induction decay signal. This then reduces the generation of noise during subsequent processing of the signal. (author)

  1. Laser magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Ferrari, C.A.

    1985-01-01

    The technique of laser resonance magnetic resonance allows one to study the high-resolution spectroscopy of transient paramagnetic species, viz, atoms, radicals, and molecular ions. This article is a brief exposition of the method, describing the principles, instrumentation and applicability of the IR and FIR-LMR and shows results of HF + . (Author) [pt

  2. Nuclear Magnetic Resonance Spectroscopy

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 9; Issue 1. Nuclear Magnetic Resonance Spectroscopy. Susanta Das. General Article Volume 9 Issue 1 January 2004 pp 34-49. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/009/01/0034-0049. Keywords.

  3. Magnetic resonance imaging

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    Magnetic resonance imaging (MRI) is a new and innovative technique that affords anatomic images in multiple planes and that may provide information about tissue characterization. The magnetic resonance images are obtained by placing the patient or the area of interest within a powerful, highly uniform, static magnetic field. Magnetized protons (hydrogen nuclei) within the patient align like small magnets in this field. Radiofrequency pulses are then used to create an oscillating magnetic field perpendicular to the main field. Magnetic resonance images differ from those produced by x-rays: the latter are associated with absorption of x-ray energy while magnetic resonance images are based on proton density and proton relaxation dynamics. Proton characteristics vary according to the tissue under examination and reflect its physical and chemical properties. To resolve issues regarding safety and efficacy, the Warren Grant Magnuson Clinical Center and the Office of Medical Applications of Research of the National Institutes of Health (NIH) convened a consensus conference about MRI Oct 26 through 28, 1987. At the NIH, the Consensus Development Conference brings together investigators in the biomedical sciences, clinical investigators, practicing physicians, and consumer and special interest groups to make a scientific assessment of technologies, including drugs, devices, and procedures, and to seek agreement on their safety and effectiveness

  4. Nuclear magnetic resonance apparatus

    International Nuclear Information System (INIS)

    Lambert, R.

    1991-01-01

    In order to include the effect of a magnetic object in a subject under investigation, Nuclear Magnetic Resonance (NMR) apparatus is operable at more than one radio frequency (RF) frequency. The apparatus allows normal practice as far as obtaining an NMR response or image from a given nuclear species is concerned, but, in addition, interrogates the nuclear spin system at a frequency which is different from the resonance frequency normally used for the given nuclear species, as determined from the applied magnetic field. The magnetic field close to a magnetised or magnetisable object is modified and the given nuclear species gives a response at the different frequency. Thus detection of a signal at the frequency indicates the presence of the chosen nuclei close to the magnetised or magnetisable object. Applications include validation of an object detection or automatic shape inspection system in the presence of magnetic impurities, and the detection of magnetic particles which affect measurement of liquid flow in a pipe. (author)

  5. Bifurcation magnetic resonance in films magnetized along hard magnetization axis

    Energy Technology Data Exchange (ETDEWEB)

    Vasilevskaya, Tatiana M., E-mail: t_vasilevs@mail.ru [Ulyanovsk State University, Leo Tolstoy 42, 432017 Ulyanovsk (Russian Federation); Sementsov, Dmitriy I.; Shutyi, Anatoliy M. [Ulyanovsk State University, Leo Tolstoy 42, 432017 Ulyanovsk (Russian Federation)

    2012-09-15

    We study low-frequency ferromagnetic resonance in a thin film magnetized along the hard magnetization axis performing an analysis of magnetization precession dynamics equations and numerical simulation. Two types of films are considered: polycrystalline uniaxial films and single-crystal films with cubic magnetic anisotropy. An additional (bifurcation) resonance initiated by the bistability, i.e. appearance of two closely spaced equilibrium magnetization states is registered. The modification of dynamic modes provoked by variation of the frequency, amplitude, and magnetic bias value of the ac field is studied. Both steady and chaotic magnetization precession modes are registered in the bifurcation resonance range. - Highlights: Black-Right-Pointing-Pointer An additional bifurcation resonance arises in a case of a thin film magnetized along HMA. Black-Right-Pointing-Pointer Bifurcation resonance occurs due to the presence of two closely spaced equilibrium magnetization states. Black-Right-Pointing-Pointer Both regular and chaotic precession modes are realized within bifurcation resonance range. Black-Right-Pointing-Pointer Appearance of dynamic bistability is typical for bifurcation resonance.

  6. Bifurcation magnetic resonance in films magnetized along hard magnetization axis

    International Nuclear Information System (INIS)

    Vasilevskaya, Tatiana M.; Sementsov, Dmitriy I.; Shutyi, Anatoliy M.

    2012-01-01

    We study low-frequency ferromagnetic resonance in a thin film magnetized along the hard magnetization axis performing an analysis of magnetization precession dynamics equations and numerical simulation. Two types of films are considered: polycrystalline uniaxial films and single-crystal films with cubic magnetic anisotropy. An additional (bifurcation) resonance initiated by the bistability, i.e. appearance of two closely spaced equilibrium magnetization states is registered. The modification of dynamic modes provoked by variation of the frequency, amplitude, and magnetic bias value of the ac field is studied. Both steady and chaotic magnetization precession modes are registered in the bifurcation resonance range. - Highlights: ► An additional bifurcation resonance arises in a case of a thin film magnetized along HMA. ► Bifurcation resonance occurs due to the presence of two closely spaced equilibrium magnetization states. ► Both regular and chaotic precession modes are realized within bifurcation resonance range. ► Appearance of dynamic bistability is typical for bifurcation resonance.

  7. Nuclear magnetic resonance scattering

    International Nuclear Information System (INIS)

    Young, I.R.

    1985-01-01

    A nuclear magnetic resonance apparatus is described including a magnet system which is capable of providing a steady magnetic field along an axis, and is constructed so as to define a plurality of regions along the axis in each of which the field is substantially homogeneous so that in each region an imaging operation may be separately carried out. Iron shields increase the field homogeneity. In use, each patient lies on a wheeled trolley which is provided with magnetic field gradient coils and an RF coil system, some of the coils being movable to facilitate positioning of the patient, and there are terminals for connection to a common computing and control facility. (author)

  8. Magnetic resonance cholangiopancreatography findings of pancreatic diseases: quantitative analysis

    International Nuclear Information System (INIS)

    Xu Jun; Lu Jianping; Wang Jian; Wang Fei; Liu Qi; Wang Li; Gong Jianguo; Jin Aiguo; Zeng Hao

    2004-01-01

    Objective: To study the MR cholangiopancreatography (MRCP) characteristics of different pancreatic diseases, and to identify the diagnostic value of MRCP for pancreatic diseases. Methods: One hundred and eleven patients with suspected pancreatic diseases underwent MRCP examination. The MRCP sequences included thick-slice turbo spin echo (TSE) and thin-slice half-Fourier acquisition single shot turbo spin echo (HASTE) sequences. The pancreatic diseases included pancreatic carcinoma (n=46), chronic pancreatitis (n=39), peri-ampullar carcinoma (n=23), and choledocholith (n=3). Results: (1) The abnormal manifestation of pancreatic duct was observed in 37 cases of pancreatic carcinoma, 24 cases of chronic pancreatitis, and 12 cases of peri-ampullar carcinoma. Dilated pancreatic duct with smooth and regular caliber was observed in 33 cases of pancreatic carcinoma, 0 case of chronic pancreatitis, and 12 cases of peri-ampullar carcinoma, and statistical analysis showed significant difference (χ 2 =57.911, P 2 =60.343, P 2 =61.217, P 2 =34.654, P 2 =54.593, P<0.01). Conclusion: Different MRI characteristics were observed in various pancreatic diseases respectively. MRCP can show the subtle differences among the pancreatic diseases, and is very helpful in the diagnosis and differential diagnosis of pancreatic diseases

  9. The magnetic resonance spectroscopy analysis for fatty acid of cooking oil

    International Nuclear Information System (INIS)

    Yu, Seung Man

    2016-01-01

    The aim of this study was to evaluate possibility for chemical changes analysis of the Soybean and Olive oil using a medical magnetic resonance imaging/spectrometer. The two edible oils including soybean and olive oil were selected for manufacturing the phantom series. For the acquisition of data without any physical environment change, 5 ml was transferred to a sealed plastic vial. All MRI and 1H-MRS experiments were performed on a 3.0 Tesla MRI scanner using a 32-channel brain array coil. The total lipid ((-CH2-)n/noise), total saturated fatty acid, total unsaturated fatty acid, total unsaturated bond, and poly unsaturated bond were quantified by separating each peak area of -CH_3, (-CH_2-)n, -CH_2-C=C-CH_2-, =C-CH_2-C=, and -CH=CH-byCH_3 by MRS analysis. Soybean oil had the highest concentration of methyl protons and methane protons, expressed as 0.9 and 5.3 ppm compared to olive oil. However, its methylene protons at 1.3 ppm were the lowest. Olive oil had the highest amount of methylene protons and allylic protons and the lowest amount of methyl protons. Through the magnetic resonance spectroscopic analysis it was to analyze the chemical characteristics of Olive oil and soybean oil. And it was confirmed that it is possible to proceed to an extended study using magnetic resonance spectroscopy

  10. The magnetic resonance spectroscopy analysis for fatty acid of cooking oil

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Seung Man [Dept. of Radiological Science, College of Health Science, Gimcheon University, Gimcheon (Korea, Republic of)

    2016-11-15

    The aim of this study was to evaluate possibility for chemical changes analysis of the Soybean and Olive oil using a medical magnetic resonance imaging/spectrometer. The two edible oils including soybean and olive oil were selected for manufacturing the phantom series. For the acquisition of data without any physical environment change, 5 ml was transferred to a sealed plastic vial. All MRI and 1H-MRS experiments were performed on a 3.0 Tesla MRI scanner using a 32-channel brain array coil. The total lipid ((-CH2-)n/noise), total saturated fatty acid, total unsaturated fatty acid, total unsaturated bond, and poly unsaturated bond were quantified by separating each peak area of -CH{sub 3}, (-CH{sub 2}-)n, -CH{sub 2}-C=C-CH{sub 2}-, =C-CH{sub 2}-C=, and -CH=CH-byCH{sub 3} by MRS analysis. Soybean oil had the highest concentration of methyl protons and methane protons, expressed as 0.9 and 5.3 ppm compared to olive oil. However, its methylene protons at 1.3 ppm were the lowest. Olive oil had the highest amount of methylene protons and allylic protons and the lowest amount of methyl protons. Through the magnetic resonance spectroscopic analysis it was to analyze the chemical characteristics of Olive oil and soybean oil. And it was confirmed that it is possible to proceed to an extended study using magnetic resonance spectroscopy.

  11. 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.

  12. Analysis of stochastic magnetic fields formed by the application of resonant magnetic perturbations on MAST and comparison with experiment

    International Nuclear Information System (INIS)

    Denner, P.; Liu, Yueqiang; Kirk, A.; Nardon, E.

    2012-01-01

    In MAST experiments with applied resonant magnetic perturbations (RMPs), clear reduction in line-averaged density has been observed in a wide range of L-mode plasmas when there is an alignment between the perturbation and the equilibrium magnetic field that maximizes the size of the resonant components of the applied magnetic field, as well as in a few H-mode plasmas but with a much stronger sensitivity to this alignment. This density pump-out is the result of increased particle transport, which is thought to be caused by the formation of a stochastic magnetic field in the plasma edge. This paper presents an analysis of the magnetic field structures formed by the application of n = 3 RMPs on MAST, including various parameters characterizing the degree of stochasticity in the plasma edge. Values for these parameters are calculated and compared with the amount of density pump-out observed in MAST experiments. It is found that density pump-out is fairly well correlated with some of the parameters calculated using vacuum modelling, but none of them provides a single threshold value for pump-out that applies to both L- and H-mode plasmas. Plasma response modelling provides a robust criterion for density pump-out that applies both to L- and H-mode plasmas. (paper)

  13. [Magnetic resonance imaging. Density equalizing mapping analysis of global research architecture].

    Science.gov (United States)

    Ohlendorf, D; Schwarze, B; Groneberg, D A; Schwarzer, M

    2015-09-01

    Despite the great medical importance, there is still no comprehensive scientometric analysis regarding the results of magnetic resonance imaging (MRI) and the development of the importance for the healthcare system. This paper evaluated and analyzed the entire research publication results on the topic of MRI for the period 1981-2007 based on scientometric methods and parameters. A scientometric analysis (database: ISI Web of Science 1981-2007, search terms MRI and magnetic resonance imaging) was performed. The following parameters were analyzed: number of publications, countries of publication, number of citations, citation rate and collaborations, using various analytical and display techniques, including density equalizing map projections. Most of the 49,122 publications on MRI could be attributed to the USA (32.5 %), which also has the most cooperative collaborations. Within Europe, Germany (10.3 %) is the country with the highest number of publications followed by the UK (9.3 %). The western industrialized nations dominate over the rest of the world in terms of scientific developments of MRI. The thematic focus of the publications lies in the fields of radiology and neuroscience. In addition to the journal Neurology most scientific articles were published in Magnetic Resonance in Medicine and Circulation. The results show that the current trend is continuing and the scientific interest in MRI is continuously increasing.

  14. Magnetic resonance and porous materials

    International Nuclear Information System (INIS)

    McDonald, P.; Strange, J.

    1998-01-01

    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)

  15. Imaging by magnetic resonance

    International Nuclear Information System (INIS)

    Duroure, J.F.; Serpolay, H.; Vallens, D.

    1995-01-01

    Here are described the advanced technology for nuclear magnetic resonance imaging: reduction of acquisition times, and rebuilding times, images quality improvement. The tendency is to open the machines at low and middle field, on a market being at 10% of NMR I sales, with economical, scientifical and ergonomic reasons broadly developed by constructors

  16. Magnetic resonance fingerprinting.

    Science.gov (United States)

    Ma, Dan; Gulani, Vikas; Seiberlich, Nicole; Liu, Kecheng; Sunshine, Jeffrey L; Duerk, Jeffrey L; Griswold, Mark A

    2013-03-14

    Magnetic resonance is an exceptionally powerful and versatile measurement technique. The basic structure of a magnetic resonance experiment has remained largely unchanged for almost 50 years, being mainly restricted to the qualitative probing of only a limited set of the properties that can in principle be accessed by this technique. Here we introduce an approach to data acquisition, post-processing and visualization--which we term 'magnetic resonance fingerprinting' (MRF)--that permits the simultaneous non-invasive quantification of multiple important properties of a material or tissue. MRF thus provides an alternative way to quantitatively detect and analyse complex changes that can represent physical alterations of a substance or early indicators of disease. MRF can also be used to identify the presence of a specific target material or tissue, which will increase the sensitivity, specificity and speed of a magnetic resonance study, and potentially lead to new diagnostic testing methodologies. When paired with an appropriate pattern-recognition algorithm, MRF inherently suppresses measurement errors and can thus improve measurement accuracy.

  17. 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…

  18. Nuclear magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Rueterjans, H.

    1987-01-01

    Contributions by various authors who are working in the field of NMR imaging present the current status and the perspectives of in-vivo nuclear magnetic resonance spectroscopy, explaining not only the scientific and medical aspects, but also technical and physical principles as well as questions concerning practical organisation and training, and points of main interest for further research activities. (orig./TRV) [de

  19. Nuclear magnetic resonance imaging

    International Nuclear Information System (INIS)

    1983-06-01

    This report summarises the aspects of nuclear magnetic resonance imaging (NMRI) considered by the National Health Technology Advisory Panel and makes recommendations on its introduction in Australia with particular regard to the need for thorough evaluation of its cost effectiveness. Topics covered are: principles of the technique, equipment required, installation, costs, reliability, performance parameters, clinical indications, training and staff requirements, and safety considerations

  20. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... for Brain Tumors Radiation Therapy for Head and Neck Cancer Others : American Stroke Association National Stroke Association ... MRA) Magnetic Resonance, Functional (fMRI) - Brain Head and Neck Cancer Treatment Brain Tumor Treatment Magnetic Resonance Imaging ( ...

  1. 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 ... What is MRI and how does it work? Magnetic resonance imaging, or MRI, is a way of obtaining ...

  2. Magnetic Resonance Imaging of Stroke

    NARCIS (Netherlands)

    Bouts, Mark. J. R. J.; Wu, O.; Dijkhuizen, R. M.

    2017-01-01

    Magnetic resonance imaging (MRI) provides a powerful (neuro)imaging modality for the diagnosis and outcome prediction after (acute) stroke. Since MRI allows noninvasive, longitudinal, and three-dimensional assessment of vessel occlusion (with magnetic resonance angiography (MRA)), tissue injury

  3. 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

  4. [Analysis of accidents for magnetically induced displacement of the large ferromagnetic material in magnetic resonance systems].

    Science.gov (United States)

    Yamatani, Yuya; Doi, Tsukasa; Ueyama, Tsuyoshi; Nishiki, Shigeo; Ogura, Akio; Kawamitsu, Hideaki; Tsuchihashi, Toshio; Okuaki, Tomoyuki; Matsuda, Tsuyoshi

    2013-01-01

    To improve magnetic resonance (MR) safety, we surveyed the accidents caused by large ferromagnetic materials brought into MR systems accidentally. We sent a questionnaire to 700 Japanese medical institutions and received 405 valid responses (58%). A total of 97 accidents in 77 institutions were observed and we analyzed them regarding incidental rate, the detail situation and environmental factors. The mean accident rate of each institute was 0.7/100,000 examinations, which was widely distributed (0-25.6/100,000) depending on the institute. In this survey, relatively small institutes with less than 500 beds tend to have these accidents more frequently (paccidents than those with less than 10 daily examinations. The institutes with 6-10 MR examinations daily have significantly more accidents than that with more than 10 daily MR examinations (paccidents were considered to be "prejudice" and "carelessness" but some advocate "ignorance." Though we could not find significant reduction in the institutes that have lectures and training for MR safety, we should continue lectures and training for MR safety to reduce accidents due to "ignorance."

  5. Children's (Pediatric) Magnetic Resonance Imaging

    Science.gov (United States)

    ... Physician Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic Resonance Imaging Children’s magnetic resonance imaging (MRI) ... limitations of Children’s (Pediatric) MRI? What is Children’s (Pediatric) MRI? Magnetic resonance imaging (MRI) is a noninvasive ...

  6. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... Physician Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic Resonance Imaging Children’s magnetic resonance imaging (MRI) ... limitations of Children’s (Pediatric) MRI? What is Children’s (Pediatric) MRI? Magnetic resonance imaging (MRI) is a noninvasive ...

  7. Magnetic Resonance Imaging (MRI) -- Head

    Science.gov (United States)

    ... 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 ...

  8. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic Resonance Imaging Children’s magnetic resonance imaging ( ... the limitations of Children’s (Pediatric) MRI? What is Children’s (Pediatric) MRI? Magnetic resonance imaging (MRI) is a ...

  9. 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 ...

  10. Resonant and nonresonant magnetic scattering (invited)

    International Nuclear Information System (INIS)

    McWhan, D.B.; Hastings, J.B.; Kao, C.; Siddons, D.P.

    1992-01-01

    The tunability and the polarization of synchrotron radiation open up new possibilities for the study of magnetism. Studies on magnetic materials performed at the National Synchrotron Light Source are reviewed, and they fall into four areas: structure, evolution of magnetic order, separation of L and S, and resonance effects. In the vicinity of atomic absorption edges, the Faraday effect, magnetic circular dichroism, and resonant magnetic scattering are all related resonance effects which measure the spin-polarized density of states. The production and analysis of polarized beams are discussed in the context of the study of magnetism with synchrotron radiation

  11. Approximate fuzzy C-means (AFCM) cluster analysis of medical magnetic resonance image (MRI) data

    International Nuclear Information System (INIS)

    DelaPaz, R.L.; Chang, P.J.; Bernstein, R.; Dave, J.V.

    1987-01-01

    The authors describe the application of an approximate fuzzy C-means (AFCM) clustering algorithm as a data dimension reduction approach to medical magnetic resonance images (MRI). Image data consisted of one T1-weighted, two T2-weighted, and one T2*-weighted (magnetic susceptibility) image for each cranial study and a matrix of 10 images generated from 10 combinations of TE and TR for each body lymphoma study. All images were obtained with a 1.5 Tesla imaging system (GE Signa). Analyses were performed on over 100 MR image sets with a variety of pathologies. The cluster analysis was operated in an unsupervised mode and computational overhead was minimized by utilizing a table look-up approach without adversely affecting accuracy. Image data were first segmented into 2 coarse clusters, each of which was then subdivided into 16 fine clusters. The final tissue classifications were presented as color-coded anatomically-mapped images and as two and three dimensional displays of cluster center data in selected feature space (minimum spanning tree). Fuzzy cluster analysis appears to be a clinically useful dimension reduction technique which results in improved diagnostic specificity of medical magnetic resonance images

  12. Magnetic resonance instrumentation

    International Nuclear Information System (INIS)

    Bell, R.A.

    1987-01-01

    Magnetic resonance (MR), while opening new vistas to diagnostic medicine, utilizes equipment that is unfamiliar to most clinicians. Beyond learning to cope with new terms, such as spin-echo, T1, T2, and spin density, health care professionals are faced with the inclusion of magnetic and radiofrequency effects in their facilities produced by a complex array of devices. It is the purpose of this chapter to outline the components of an MR imaging system, to discuss their functions, and to note the variations in equipment commercially available

  13. Magnetic resonance imaging

    International Nuclear Information System (INIS)

    Sigal, R.

    1988-01-01

    This book is an introduction to magnetic resonance imaging (MRI). The basic principles for the interpretation of MR images are developed. The book is divided into five chapters: introduction, tissue, parameters, acquisition parameters, contribution to diagnosis, and practical management of an MR examination. Eight exercises allow the reader to test the knowledge he has acquired. Signal localization and MR artefacts are reviewed in an appendix

  14. Magnetic resonance imaging (MRI

    Directory of Open Access Journals (Sweden)

    Takavar A

    1993-04-01

    Full Text Available Basic physical principles of nuclear magnetic resonance imaging (N.M.R.I, a nonionizing medical imaging technique, are described. Principles of NMRI with other conventional imaging methods, ie, isotope scanning, ultrasonography and radiography have been compared. T1 and T2 and spin density (S.D. factors and different image construction techniques based on their different combinations is discussed and at the end physical properties of some N.M.R images is mentioned.

  15. Magnetic resonance imaging (MRI)

    OpenAIRE

    Takavar A

    1993-01-01

    Basic physical principles of nuclear magnetic resonance imaging (N.M.R.I), a nonionizing medical imaging technique, are described. Principles of NMRI with other conventional imaging methods, ie, isotope scanning, ultrasonography and radiography have been compared. T1 and T2 and spin density (S.D.) factors and different image construction techniques based on their different combinations is discussed and at the end physical properties of some N.M.R images is mentioned.

  16. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... magnetic resonance imaging (MRI) uses a powerful magnetic field, radio waves and a computer to produce detailed ... problems, medications, recent surgeries and allergies. The magnetic field is not harmful, but it may cause some ...

  17. The performance of magnetic resonance imaging in the detection of triangular fibrocartilage complex injury: a meta-analysis.

    Science.gov (United States)

    Wang, Z X; Chen, S L; Wang, Q Q; Liu, B; Zhu, J; Shen, J

    2015-06-01

    The aim of this study was to evaluate the accuracy of magnetic resonance imaging in the detection of triangular fibrocartilage complex injury through a meta-analysis. A comprehensive literature search was conducted before 1 April 2014. All studies comparing magnetic resonance imaging results with arthroscopy or open surgery findings were reviewed, and 25 studies that satisfied the eligibility criteria were included. Data were pooled to yield pooled sensitivity and specificity, which were respectively 0.83 and 0.82. In detection of central and peripheral tears, magnetic resonance imaging had respectively a pooled sensitivity of 0.90 and 0.88 and a pooled specificity of 0.97 and 0.97. Six high-quality studies using Ringler's recommended magnetic resonance imaging parameters were selected for analysis to determine whether optimal imaging protocols yielded better results. The pooled sensitivity and specificity of these six studies were 0.92 and 0.82, respectively. The overall accuracy of magnetic resonance imaging was acceptable. For peripheral tears, the pooled data showed a relatively high accuracy. Magnetic resonance imaging with appropriate parameters are an ideal method for diagnosing different types of triangular fibrocartilage complex tears. © The Author(s) 2015.

  18. Contributed Review: Nuclear magnetic resonance core analysis at 0.3 T

    International Nuclear Information System (INIS)

    Mitchell, Jonathan; Fordham, Edmund J.

    2014-01-01

    Nuclear magnetic resonance (NMR) provides a powerful toolbox for petrophysical characterization of reservoir core plugs and fluids in the laboratory. Previously, there has been considerable focus on low field magnet technology for well log calibration. Now there is renewed interest in the study of reservoir samples using stronger magnets to complement these standard NMR measurements. Here, the capabilities of an imaging magnet with a field strength of 0.3 T (corresponding to 12.9 MHz for proton) are reviewed in the context of reservoir core analysis. Quantitative estimates of porosity (saturation) and pore size distributions are obtained under favorable conditions (e.g., in carbonates), with the added advantage of multidimensional imaging, detection of lower gyromagnetic ratio nuclei, and short probe recovery times that make the system suitable for shale studies. Intermediate field instruments provide quantitative porosity maps of rock plugs that cannot be obtained using high field medical scanners due to the field-dependent susceptibility contrast in the porous medium. Example data are presented that highlight the potential applications of an intermediate field imaging instrument as a complement to low field instruments in core analysis and for materials science studies in general

  19. Magnetic Resonance Cholangiopancreatographv: A Meta-Analysis of Test Performance in Suspected Biliary Disease

    International Nuclear Information System (INIS)

    Romagnuolo J; Bardou M; Rahme, E and others

    2004-01-01

    Magnetic resonance cholangiopancreatography (MRCP) is one of many newer noninvasive tests that can image the biliary tree. To precisely estimate the overall sensitivity and specificity of MRCP in suspected biliary obstruction and to evaluate clinically important subgroups. MEDLINE search (January 1987 to March 2003) for studies in English or French, bibliographies, and subject matter experts. Studies were included if they allowed construction of 2x2 contingency tables of MRCP compared with a reasonable gold standard for at least 1 of the following: the presence, level, or cause of biliary obstruction. Two independent observers graded study quality, which included consecutive enrollment, blinding, use of a single (versus composite) gold standard, and nonselective use of the gold standard. Logistic regression was used to examine the influence of publication year, quality score, proportion of patients having a direct gold standard, and clinical context on diagnostic performance. Of 498 studies identified, 67 were included (4711 patients). Mixed-effect models were used to estimate the sensitivity and specificity, and quantitative receiver-operating characteristic analysis was performed. Magnetic resonance cholangiopancreatography had a high overall pooled sensitivity (95% (+/-1.96 SD: spread of SD, 75% to 99%) and specificity (97% (spread of SD, 86% to 99 %)) The procedure was less sensitive for stones (92%; odds ratio, 0.51 (CI, 0.35 to 0.75) and malignant conditions (88%; odds ratio, 0.28 (CI, 0.18 to 0.44f) than for the presence of obstruction, In addition, diagnostic performance was higher in studies that were larger, did not use consecutive enrollment, and did not use gold standard assessment for some patients. Magnetic resonance cholangiopancreatography is a noninvasive imaging test with excellent overall sensitivity and specificity for demonstrating the level and presence of biliary obstruction; however, it seems less sensitive for detecting stones or

  20. Introduction lecture to magnetic resonance

    International Nuclear Information System (INIS)

    Conard, J.

    1980-01-01

    This lecture deals with all that is common either to electron paramagnetic resonance (E.P.R.) or to nuclear magnetic resonance (N.M.R.). It will present, in an as elementary form as possible, the main concepts used in magnetic resonance emphasizing some aspects, specific for interface science. (orig./BHO)

  1. Advanced Nuclear Magnetic Resonance

    OpenAIRE

    Alonso, Diego A.

    2014-01-01

    Transparencias en inglés de la asignatura "Resonancia Magnética Nuclear Avanzada" (Advanced Nuclear Magnetic Resonance) (36643) que se imparte en el Máster de Química Médica como asignatura optativa de 3 créditos ECTS. En esta asignatura se completa el estudio iniciado en la asignatura de quinto curso de la licenciatura en Química "Determinación estructural" (7448) y en la del Grado de Química de tercer curso "Determinación estructural de los compuestos orgánicos" (26030) en lo referente a té...

  2. Cranial magnetic resonance imaging

    International Nuclear Information System (INIS)

    Elster, A.D.

    1988-01-01

    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)

    Hilgenfeld, Tim; Bendszus, Martin; Haehnel, Stefan

    2016-01-01

    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. Multidirectional flow analysis by cardiovascular magnetic resonance in aneurysm development following repair of aortic coarctation

    Directory of Open Access Journals (Sweden)

    Stalder Aurelien F

    2008-06-01

    Full Text Available Abstract Aneurysm formation is a life-threatening complication after operative therapy in coarctation. The identification of patients at risk for the development of such secondary pathologies is of high interest and requires a detailed understanding of the link between vascular malformation and altered hemodynamics. The routine morphometric follow-up by magnetic resonance angiography is a well-established technique. However, the intrinsic sensitivity of magnetic resonance (MR towards motion offers the possibility to additionally investigate hemodynamic consequences of morphological changes of the aorta. We demonstrate two cases of aneurysm formation 13 and 35 years after coarctation surgery based on a Waldhausen repair with a subclavian patch and a Vosschulte repair with a Dacron patch, respectively. Comprehensive flow visualization by cardiovascular MR (CMR was performed using a flow-sensitive, 3-dimensional, and 3-directional time-resolved gradient echo sequence at 3T. Subsequent analysis included the calculation of a phase contrast MR angiography and color-coded streamline and particle trace 3D visualization. Additional quantitative evaluation provided regional physiological information on blood flow and derived vessel wall parameters such as wall shear stress and oscillatory shear index. The results highlight the individual 3D blood-flow patterns associated with the different vascular pathologies following repair of aortic coarctation. In addition to known factors predisposing for aneurysm formation after surgical repair of coarctation these findings indicate the importance of flow sensitive CMR to follow up hemodynamic changes with respect to the development of vascular disease.

  5. Nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Cremin, B.J.

    1981-01-01

    Recent advances in diagnostic imaging, have been the medical application of nuclear magnetic resonance (NMR). It's been used to study the structure of various compounds in chemistry and physics, and in the mid-1970 to produce images of rabbits and eventually of the human hand and head. The images are produced by making use of the nuclear magnetization of the hydrogen ion, or proton, that is present in biological material to record the density distribution of protons in cellular water and lipids. An exploration of the end-results of complicated free induction decay signals, that have been digitized and frequency-analysed by mathematical computerized techniques to produce an image of tissue density, is given. At present NMR produces images comparable to those of early computed tomography

  6. Synthesis and Analysis of Methacryloyl-L-Alanine Methyl Ester using fourier Transform Nuclear Magnetic Resonance

    International Nuclear Information System (INIS)

    Tri Darwinto

    2008-01-01

    Methacryloyl-L-alanine methyl ester was synthesized by reacting methacrylic acid with L-alanine methyl ester hydrochloride in triethylamine at temperature of 90 o C. Hydrogel polymer of poly(methacryloyl-L-alanine methyl ester) was much used for diagnosis and therapy of vascular tumor. The molecular structure methacryloyl-L-alanine methyl ester analyzed by fourier transform nuclear magnetic resonance (FT-NMR) for analyzing of carbon atom ( 13 C) using Distortionless Enhancement by Polarization Transfer (DEPT) measurement mode with coupling as well as without coupling from proton atom ( 1 H). Molecular structure analysis result showed that DEPT FT-NMR measurement mode with coupling as well as without coupling from 1 H was very fast, exact and accurate method for molecular analysis of organic compound especially methacryloyl-L-alanine methyl ester. (author)

  7. 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.

  8. Nuclear magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Rabenstein, D.L.; Guo, W.

    1988-01-01

    Nuclear magnetic resonance (NMR) spectroscopy is one of the most widely used instrumental methods, with applications ranging from the characterization of pure compounds by high-resolution NMR to the diagnosis of disease by magnetic resonance imaging (MRI). To give some idea of the wide-spread use of NMR, a computer search for the period 1985-1987 turned up over 500 books and review articles and over 7000 literature citations, not including papers in which NMR was used together with other spectroscopic methods for the routine identification of organic compounds. Consequently, they have by necessity been somewhat selective in the topics they have chosen to cover and in the articles they have cited. In this review, which covers the published literature for the approximate period Sept 1985-Aug 1987, they have focused on new developments and applications of interest to the chemist. First they review recent developments in instrumentation and techniques. Although there have not been any major break-throughs in NMR instrumentation during the past two years, significant refinements have been reported which optimize instrumentation for the demanding multiple pulse experiments in routine use today. Next they review new developments in methods for processing NMR data, followed by reviews of one-dimensional and two-dimensional NMR experiments

  9. 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

  10. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... immediately after the exam. A few patients experience side effects from the contrast material, including nausea and local ... Related Articles and Media Catheter Angiography Magnetic Resonance, Functional (fMRI) - Brain Children's (Pediatric) CT (Computed Tomography) Magnetic ...

  11. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... by the interpreting radiologist. Frequently, the differentiation of abnormal (diseased) tissue from normal tissues is better with ... Tumor Treatment Magnetic Resonance Imaging (MRI) Safety Alzheimer's Disease Head Injury Brain Tumors Images related to Magnetic ...

  12. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... Related Articles and Media Catheter Angiography Magnetic Resonance, Functional (fMRI) - Brain Children's (Pediatric) CT (Computed Tomography) Magnetic ... the possible charges you will incur. Web page review process: This Web page is reviewed regularly by ...

  13. Probing beer aging chemistry by nuclear magnetic resonance and multivariate analysis

    International Nuclear Information System (INIS)

    Rodrigues, J.A.; Barros, A.S.; Carvalho, B.; Brandao, T.; Gil, Ana M.

    2011-01-01

    Graphical abstract: The use of nuclear magnetic resonance (NMR) metabonomics for monitoring the chemical changes occurring in beer exposed to forced aging (at 45 deg. C for up to 18 days) is described. Both principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were applied to the NMR spectra of beer recorded as a function of aging and an aging trend was observed. Inspection of PLS-DA loadings and peak integration revealed the importance of well known markers (e.g. 5-HMF) as well as of other compounds: amino acids, higher alcohols, organic acids, dextrins and some still unassigned spin systems. 2D correlation analysis enabled relevant compound variations to be confirmed and inter-compound correlations to be assessed, thus offering improved insight into the chemical aspects of beer aging. Highlights: · Use of NMR metabonomics for monitoring the chemical changes occurring in beer exposed to forced aging. · Compositional variations evaluated by principal component analysis and partial least squares-discriminant analysis. · Results reveal importance of known markers and other compounds: amino and organic acids, higher alcohols, dextrins. · 2D correlation analysis reveals inter-compound relationships, offering insight into beer aging chemistry. - Abstract: This paper describes the use of nuclear magnetic resonance (NMR) spectroscopy, in tandem with multivariate analysis (MVA), for monitoring the chemical changes occurring in a lager beer exposed to forced aging (at 45 deg. C for up to 18 days). To evaluate the resulting compositional variations, both principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were applied to the NMR spectra of beer recorded as a function of aging and a clear aging trend was observed. Inspection of PLS-DA loadings and peak integration enabled the changing compounds to be identified, revealing the importance of well known markers such as 5-hydroxymethylfurfural (5

  14. Probing beer aging chemistry by nuclear magnetic resonance and multivariate analysis

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, J.A. [CICECO-Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); Barros, A.S. [QOPNA-Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); Carvalho, B.; Brandao, T. [UNICER, Bebidas de Portugal, Leca do Balio, 4466-955, S. Mamede de Infesta (Portugal); Gil, Ana M., E-mail: agil@ua.pt [CICECO-Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal)

    2011-09-30

    Graphical abstract: The use of nuclear magnetic resonance (NMR) metabonomics for monitoring the chemical changes occurring in beer exposed to forced aging (at 45 deg. C for up to 18 days) is described. Both principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were applied to the NMR spectra of beer recorded as a function of aging and an aging trend was observed. Inspection of PLS-DA loadings and peak integration revealed the importance of well known markers (e.g. 5-HMF) as well as of other compounds: amino acids, higher alcohols, organic acids, dextrins and some still unassigned spin systems. 2D correlation analysis enabled relevant compound variations to be confirmed and inter-compound correlations to be assessed, thus offering improved insight into the chemical aspects of beer aging. Highlights: {center_dot} Use of NMR metabonomics for monitoring the chemical changes occurring in beer exposed to forced aging. {center_dot} Compositional variations evaluated by principal component analysis and partial least squares-discriminant analysis. {center_dot} Results reveal importance of known markers and other compounds: amino and organic acids, higher alcohols, dextrins. {center_dot} 2D correlation analysis reveals inter-compound relationships, offering insight into beer aging chemistry. - Abstract: This paper describes the use of nuclear magnetic resonance (NMR) spectroscopy, in tandem with multivariate analysis (MVA), for monitoring the chemical changes occurring in a lager beer exposed to forced aging (at 45 deg. C for up to 18 days). To evaluate the resulting compositional variations, both principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were applied to the NMR spectra of beer recorded as a function of aging and a clear aging trend was observed. Inspection of PLS-DA loadings and peak integration enabled the changing compounds to be identified, revealing the importance of well known

  15. Characterization of polymer-type ionic conductors using nuclear magnetic resonance and thermal analysis. Humidity sensor

    International Nuclear Information System (INIS)

    Cavalcante, Maria Goretti.

    1992-04-01

    We report a study using Nuclear Magnetic Resonance (NMR), Thermogravimetry Analysis, Differential Scanning Calorimetry and Infrared Spectroscopy in polymeric complexes formed poly(ethylene oxide), (PEO), and lithium salts. These complexes have have shown a large potential for technological applications in batteries, sensors, etc. We developed and characterized humidity sensors and discussed how the humidity affects the conformation of the complexes, the mobility of ionic species, and the polymeric chains. The results indicate that the hydration affects the conformation of polymeric complexes by plasticizing the water, which induces a volumetric expansion in the PEO chain. The processes was completely reversible for the level of hydration studied. NMR was used to distinguish the movement of polymeric chains from the movement of the ionic species. From the analysis of the second moment of resonance lines from the study of the nuclear relaxation we were able to estimate the average distance between the ionic species and the proton in the complexes chains. The behaviour of spin -lattice relaxation of hydrogen and fluorine in the P(EO) - Li B F, as a function of temperature and frequency reflects the nature of the disorder and the complexity of the ionic conduction process in these materials. (author). 91 refs., 69 figs., 2 tabs

  16. Iterative Development of an Application to Support Nuclear Magnetic Resonance Data Analysis of Proteins.

    Science.gov (United States)

    Ellis, Heidi J C; Nowling, Ronald J; Vyas, Jay; Martyn, Timothy O; Gryk, Michael R

    2011-04-11

    The CONNecticut Joint University Research (CONNJUR) team is a group of biochemical and software engineering researchers at multiple institutions. The vision of the team is to develop a comprehensive application that integrates a variety of existing analysis tools with workflow and data management to support the process of protein structure determination using Nuclear Magnetic Resonance (NMR). The use of multiple disparate tools and lack of data management, currently the norm in NMR data processing, provides strong motivation for such an integrated environment. This manuscript briefly describes the domain of NMR as used for protein structure determination and explains the formation of the CONNJUR team and its operation in developing the CONNJUR application. The manuscript also describes the evolution of the CONNJUR application through four prototypes and describes the challenges faced while developing the CONNJUR application and how those challenges were met.

  17. Alzheimer's Disease Detection in Brain Magnetic Resonance Images Using Multiscale Fractal Analysis

    International Nuclear Information System (INIS)

    Lahmiri, Salim; Boukadoum, Mounir

    2013-01-01

    We present a new automated system for the detection of brain magnetic resonance images (MRI) affected by Alzheimer's disease (AD). The MRI is analyzed by means of multiscale analysis (MSA) to obtain its fractals at six different scales. The extracted fractals are used as features to differentiate healthy brain MRI from those of AD by a support vector machine (SVM) classifier. The result of classifying 93 brain MRIs consisting of 51 images of healthy brains and 42 of brains affected by AD, using leave-one-out cross-validation method, yielded 99.18% ± 0.01 classification accuracy, 100% sensitivity, and 98.20% ± 0.02 specificity. These results and a processing time of 5.64 seconds indicate that the proposed approach may be an efficient diagnostic aid for radiologists in the screening for AD

  18. OXSA: An open-source magnetic resonance spectroscopy analysis toolbox in MATLAB.

    Directory of Open Access Journals (Sweden)

    Lucian A B Purvis

    Full Text Available In vivo magnetic resonance spectroscopy provides insight into metabolism in the human body. New acquisition protocols are often proposed to improve the quality or efficiency of data collection. Processing pipelines must also be developed to use these data optimally. Current fitting software is either targeted at general spectroscopy fitting, or for specific protocols. We therefore introduce the MATLAB-based OXford Spectroscopy Analysis (OXSA toolbox to allow researchers to rapidly develop their own customised processing pipelines. The toolbox aims to simplify development by: being easy to install and use; seamlessly importing Siemens Digital Imaging and Communications in Medicine (DICOM standard data; allowing visualisation of spectroscopy data; offering a robust fitting routine; flexibly specifying prior knowledge when fitting; and allowing batch processing of spectra. This article demonstrates how each of these criteria have been fulfilled, and gives technical details about the implementation in MATLAB. The code is freely available to download from https://github.com/oxsatoolbox/oxsa.

  19. Analysis on the power and efficiency in wireless power transfer system via coupled magnetic resonances

    Science.gov (United States)

    Liu, Mingjie

    2018-06-01

    The analysis of characteristics of the power and efficiency in wireless power transmission (WPT) system is the theoretical basis of magnetic coupling resonant wireless power transmission (MCR-WPT) technology. The electromagnetic field theory was employed to study the variation of the coupling degree of the two electromagnetic coils with the parameters of the coils. The equivalent circuit was used to analyze the influence of different factors on the transmission power and efficiency of the WPT system. The results show that there is an optimal radius ratio between the two coils, which makes the mutual inductance of the coils the largest. Moreover, when the WPT system operates in the under-coupling state, the transmission power of the system drops sharply, and there is a frequency splitting of the power when in the over-coupling state.

  20. Linear-fitting-based similarity coefficient map for tissue dissimilarity analysis in -w magnetic resonance imaging

    International Nuclear Information System (INIS)

    Yu Shao-De; Wu Shi-Bin; Xie Yao-Qin; Wang Hao-Yu; Wei Xin-Hua; Chen Xin; Pan Wan-Long; Hu Jiani

    2015-01-01

    Similarity coefficient mapping (SCM) aims to improve the morphological evaluation of weighted magnetic resonance imaging However, how to interpret the generated SCM map is still pending. Moreover, is it probable to extract tissue dissimilarity messages based on the theory behind SCM? The primary purpose of this paper is to address these two questions. First, the theory of SCM was interpreted from the perspective of linear fitting. Then, a term was embedded for tissue dissimilarity information. Finally, our method was validated with sixteen human brain image series from multi-echo . Generated maps were investigated from signal-to-noise ratio (SNR) and perceived visual quality, and then interpreted from intra- and inter-tissue intensity. Experimental results show that both perceptibility of anatomical structures and tissue contrast are improved. More importantly, tissue similarity or dissimilarity can be quantified and cross-validated from pixel intensity analysis. This method benefits image enhancement, tissue classification, malformation detection and morphological evaluation. (paper)

  1. Investigation of magnetic resonance imaging texture analysis as an aid tool for characterization of refractory epilepsies

    Directory of Open Access Journals (Sweden)

    Mauricio Martins Baldissin

    2013-12-01

    Full Text Available Refractory epilepsies are syndromes for which therapies that employ two or more antiepileptic drugs, separately or in association, do not result in control of crisis. Patients may present focal cortical dysplasia or diffuse dysplasia and/or hippocampal atrophic alterations that may not be detectable by a simple visual analysis in magnetic resonance imaging. The aim of this study was to evaluate MRI texture in regions of interest located in the hippocampi, limbic association cortex and prefrontal cortex of 20 patients with refractory epilepsy and to compare them with the same areas in 20 healthy individuals, in order to find out if the texture parameters could be related to the presence of the disease. Of the 11 texture parameters calculated, three indicated the existence of statistically significant differences between the studied groups. Such findings suggest the possibility of this technique contributing to studies of refractory epilepsies.

  2. OXSA: An open-source magnetic resonance spectroscopy analysis toolbox in MATLAB.

    Science.gov (United States)

    Purvis, Lucian A B; Clarke, William T; Biasiolli, Luca; Valkovič, Ladislav; Robson, Matthew D; Rodgers, Christopher T

    2017-01-01

    In vivo magnetic resonance spectroscopy provides insight into metabolism in the human body. New acquisition protocols are often proposed to improve the quality or efficiency of data collection. Processing pipelines must also be developed to use these data optimally. Current fitting software is either targeted at general spectroscopy fitting, or for specific protocols. We therefore introduce the MATLAB-based OXford Spectroscopy Analysis (OXSA) toolbox to allow researchers to rapidly develop their own customised processing pipelines. The toolbox aims to simplify development by: being easy to install and use; seamlessly importing Siemens Digital Imaging and Communications in Medicine (DICOM) standard data; allowing visualisation of spectroscopy data; offering a robust fitting routine; flexibly specifying prior knowledge when fitting; and allowing batch processing of spectra. This article demonstrates how each of these criteria have been fulfilled, and gives technical details about the implementation in MATLAB. The code is freely available to download from https://github.com/oxsatoolbox/oxsa.

  3. Magnetic resonance imaging of the pituitary adenoma: Analysis of the enhancement patterns

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ik; Choi, Woo Suk; Shin, In Soo; Ryu, Kyung Nam; Yoon, Yup [Kyung Hee University Hospital, Seoul (Korea, Republic of)

    1993-11-15

    The magnetic resonance images (MRI) of 30 patients with surgically or biochemically confirmed pituitary adenomas (20 macroadenomas, 10 microadenomas) were retrospectively evaluated. Ten patients had hyperprolactinaemia, another eight had acromegaly, another eight had nonfunctioning adenoma and four had cushing disease. The examinations were performed at a1.5 T superconducting MR system using a multisection spin-echo technique with 3 mm thick sections and a 256 X 224 matrix. TI weighted sagittal and coronal images were obtained before and within 30 minutes after the administration of Gd-DTPA (0.1 mmol/kg). Analysis of the MRI was focused on the signal intensity and enhancement patterns of the pituitary adenoma before and after Gd-DTPA administration. Compared with endocrinological diagnosis, macroadenoma showed heterogeneous enhancement in 55%, rim enhancement in 35% and homogeneous enhancement in 10%. Conclusively, the enhancement patterns of the pituitary adenoma did not correlate with the subtypes made according to hormone production.

  4. Magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Meyerhoff, D.J.; Weiner, M.W.

    1989-01-01

    A major function of the liver is regulation of carbohydrate, lipid, and nitrogen metabolism. Food is absorbed by the intestines and transported to the liver by the portal circulation. Substrates are metabolized and stored in the liver to maintain optimal blood concentrations of glucose and lipids. Ammonia generated in the gastrointestinal tract is converted to urea in the liver by the urea cycle. Various forms of liver disease are associated with disorders of carbohydrate, fat, and nitrogen metabolism. Therefore the ability to characterize liver metabolism noninvasively is of potential diagnostic value. Magnetic resonance spectroscopy (MRS) provides information about tissue metabolism by measuring concentrations of metabolites. However, to determine the anatomic location from which spectroscopic signals are derived, MRS could be performed in conjunction with MRI. This paper summarizes the current experience with spectroscopy ion animal models of human disease and reviews the clinical experience with hepatic MRS to date

  5. Magnetic resonance in neuroborreliosis

    International Nuclear Information System (INIS)

    Ustymowicz, A.; Zajkowska, J.

    2003-01-01

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

  6. Cine magnetic resonance

    International Nuclear Information System (INIS)

    Higgins, C.B.; Sechtem, U.P.; Pflugfelder, P.

    1987-01-01

    Cine magnetic resonance (MR) is a fast MR imaging process with referencing of the imaging data to the electrocardiogram (ECG) so that images corresponding to 21-msec segments of the cardiac cycle are acquired. A series of such images, each corresponding to a 21-msec segment of the cardiac cycle, can be laced together for viewing in the cine format at a framing rate of 20 to 40 frames per second. Since cine angiograms of the heart are usually done at 30 frames per second, this technique achieves a temporal resolution adequate for the evluation of central cardiovascular function. The major application of this technique is to depict central cardiovascular function and blood flow

  7. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic Resonance Imaging Children’s magnetic resonance imaging (MRI) uses a powerful ... for an MRI exam contains a metal called gadolinium . Gadolinium can be used in patients with iodine ...

  8. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... work? Unlike conventional x-ray examinations and computed tomography (CT) scans, MRI does not utilize ionizing radiation. Instead, ... Angiography Magnetic Resonance, Functional (fMRI) - Brain Children's (Pediatric) CT (Computed Tomography) Magnetic Resonance Imaging (MRI) Safety Contrast Materials Children ...

  9. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic Resonance Imaging Children’s magnetic resonance imaging (MRI) uses ... identify and accurately characterize diseases than other imaging methods. This detail makes MRI an invaluable tool in ...

  10. Magnetic resonance of low dimensional magnetic solids

    Energy Technology Data Exchange (ETDEWEB)

    Gatteschi, D.; Ferraro, F.; Sessoli, R. (Florence Univ. (Italy))

    1994-06-01

    The utility of EPR and NMR in the study of low-dimensional magnetic solids is shown. A short summary of the basis of magnetic resonance in these systems is reported, and the importance of spin-diffusion and magnetic anisotropy evidenced. Some results from experiments on metal-radical chains and clusters are presented. (authors). 37 refs., 7 figs.

  11. Magnetic resonance of low dimensional magnetic solids

    International Nuclear Information System (INIS)

    Gatteschi, D.; Ferraro, F.; Sessoli, R.

    1994-01-01

    The utility of EPR and NMR in the study of low-dimensional magnetic solids is shown. A short summary of the basis of magnetic resonance in these systems is reported, and the importance of spin-diffusion and magnetic anisotropy evidenced. Some results from experiments on metal-radical chains and clusters are presented. (authors). 37 refs., 7 figs

  12. 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

  13. Analysis of Magnetic Resonance Image Signal Fluctuations Acquired During MR-Guided Radiotherapy.

    Science.gov (United States)

    Breto, Adrian L; Padgett, Kyle R; Ford, John C; Kwon, Deukwoo; Chang, Channing; Fuss, Martin; Stoyanova, Radka; Mellon, Eric A

    2018-03-28

    Magnetic resonance-guided radiotherapy (MRgRT) is a new and evolving treatment modality that allows unprecedented visualization of the tumor and surrounding anatomy. MRgRT includes daily 3D magnetic resonance imaging (MRI) for setup and rapidly repeated near real-time MRI scans during treatment for target tracking. One of the more exciting potential benefits of MRgRT is the ability to analyze serial MRIs to monitor treatment response or predict outcomes. A typical radiation treatment (RT) over the span of 10-15 minutes on the MRIdian system (ViewRay, Cleveland, OH) yields thousands of "cine" images, each acquired in 250 ms. This unique data allows for a glimpse in image intensity changes during RT delivery. In this report, we analyze cine images from a single fraction RT of a glioblastoma patient on the ViewRay platform in order to characterize the dynamic signal changes occurring during RT therapy. The individual frames in the cines were saved into DICOM format and read into an MIM image analysis platform (MIM Software, Cleveland, OH) as a time series. The three possible states of the three Cobalt-60 radiation sources-OFF, READY, and ON-were also recorded. An in-house Java plugin for MIM was created in order to perform principal component analysis (PCA) on each of the datasets. The analysis resulted in first PC, related to monotonous signal increase over the course of the treatment fraction. We found several distortion patterns in the data that we postulate result from the perturbation of the magnetic field due to the moving metal parts in the platform while treatment was being administered. The largest variations were detected when all Cobalt-60 sources were OFF. During this phase of the treatment, the gantry and multi-leaf collimators (MLCs) are moving. Conversely, when all Cobalt-60 sources were in the ON position, the image signal fluctuations were minimal, relating to very little mechanical motion. At this phase, the gantry, the MLCs, and sources are fixed

  14. Diffusion tensor analysis with nuclear magnetic resonance in human central nervous system

    International Nuclear Information System (INIS)

    Nakayama, Naoki

    1998-01-01

    Nuclear magnetic resonance has been used to measure the diffusivity of water molecules. In central nervous system, anisotropic diffusion, which is characterized by apparent diffusion tensor D app ξ , is thought to be related to neuronal fiber tract orientation. For precise observation of anisotropic diffusion, it is needed to determine the diagonal and off-diagonal elements of D app ξ . Once D app ξ is estimated from a series of diffusion weighted images, a tissue's orthotropic principal axes and diffusivity of each direction are determined from eigenvalues and eigenvectors of D app ξ . There are several methods to represent anisotropic diffusion with D app ξ . Examples are diffusion ellipsoids constructed in each voxel depicting both these principal axes and the mean diffusion length in these directions, trace invariant values and its mapping image, largest eigenvalue, and ratio of largest eigenvalue to the other eigenvalue. In this study, the author investigated practical procedure to analyze diffusion tensor D app ξ using both of spin-echo end echo-planer diffusion weighted imagings with 3-tesla magnetic resonance machine in human brain. The ellipsoid representation provided particularly useful information about microanatomy including neuronal fiber tract orientation and molecular mobility reflective of microstructure. Furthermore, in the lesion of Wallerian degeneration, the loss of anisotropy of local apparent diffusion was observed. It is suggested that the function of axons can be observed via degree of anisotropy of apparent diffusion. Consequently, diffusion tensor analysis is expected to be a powerful, noninvasive method capable of quantitative and functional evaluation of the central nervous system. (author)

  15. Magnetic resonance imaging methodology

    International Nuclear Information System (INIS)

    Moser, Ewald; Stadlbauer, Andreas; Windischberger, Christian; Quick, Harald H.; Ladd, Mark E.

    2009-01-01

    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.)

  16. Measurement precision and biological variation of cranial arteries using automated analysis of 3 T magnetic resonance angiography

    DEFF Research Database (Denmark)

    Amin, Faisal Mohammad; Lundholm, Elisabet; Hougaard, Anders

    2014-01-01

    BACKGROUND: Non-invasive magnetic resonance angiography (MRA) has facilitated repeated measurements of human cranial arteries in several headache and migraine studies. To ensure comparability across studies the same automated analysis software has been used, but the intra- and interobserver, day-...

  17. Performance analysis and experimental verification of mid-range wireless energy transfer through non-resonant magnetic coupling

    DEFF Research Database (Denmark)

    Peng, Liang; Wang, Jingyu; Zhejiang University, Hangzhou, China, L.

    2011-01-01

    In this paper, the efficiency analysis of a mid-range wireless energy transfer system is performed through non-resonant magnetic coupling. It is shown that the self-resistance of the coils and the mutual inductance are critical in achieving a high efficiency, which is indicated by our theoretical...

  18. Assessment of acute myocarditis by cardiac magnetic resonance imaging: Comparison of qualitative and quantitative analysis methods.

    Science.gov (United States)

    Imbriaco, Massimo; Nappi, Carmela; Puglia, Marta; De Giorgi, Marco; Dell'Aversana, Serena; Cuocolo, Renato; Ponsiglione, Andrea; De Giorgi, Igino; Polito, Maria Vincenza; Klain, Michele; Piscione, Federico; Pace, Leonardo; Cuocolo, Alberto

    2017-10-26

    To compare cardiac magnetic resonance (CMR) qualitative and quantitative analysis methods for the noninvasive assessment of myocardial inflammation in patients with suspected acute myocarditis (AM). A total of 61 patients with suspected AM underwent coronary angiography and CMR. Qualitative analysis was performed applying Lake-Louise Criteria (LLC), followed by quantitative analysis based on the evaluation of edema ratio (ER) and global relative enhancement (RE). Diagnostic performance was assessed for each method by measuring the area under the curves (AUC) of the receiver operating characteristic analyses. The final diagnosis of AM was based on symptoms and signs suggestive of cardiac disease, evidence of myocardial injury as defined by electrocardiogram changes, elevated troponin I, exclusion of coronary artery disease by coronary angiography, and clinical and echocardiographic follow-up at 3 months after admission to the chest pain unit. In all patients, coronary angiography did not show significant coronary artery stenosis. Troponin I levels and creatine kinase were higher in patients with AM compared to those without (both P quantitative (ER 0.89 and global RE 0.80) analyses were also similar. Qualitative and quantitative CMR analysis methods show similar diagnostic accuracy for the diagnosis of AM. These findings suggest that a simplified approach using a shortened CMR protocol including only T2-weighted STIR sequences might be useful to rule out AM in patients with acute coronary syndrome and normal coronary angiography.

  19. Analysis of 3-D Tongue Motion from Tagged and Cine Magnetic Resonance Images

    Science.gov (United States)

    Xing, Fangxu; Woo, Jonghye; Lee, Junghoon; Murano, Emi Z.; Stone, Maureen; Prince, Jerry L.

    2016-01-01

    Purpose: Measuring tongue deformation and internal muscle motion during speech has been a challenging task because the tongue deforms in 3 dimensions, contains interdigitated muscles, and is largely hidden within the vocal tract. In this article, a new method is proposed to analyze tagged and cine magnetic resonance images of the tongue during…

  20. Sc-45 nuclear magnetic resonance analysis of precipitation in dilute Al-Sc alloys

    NARCIS (Netherlands)

    Celotto, S; Bastow, TJ

    Nuclear magnetic resonance (NMR) with Sc-45 is used to determine the solid solubility of scandium in aluminium and to follow the precipitation of Al3Sc during the ageing of an Al-0.06 at.% Sc alloy via the two fully resolved peaks, corresponding to Sc in the solid solution Al matrix and to Sc in the

  1. Quantification of lipoprotein profiles by nuclear magnetic resonance spectroscopy and multivariate data analysis

    DEFF Research Database (Denmark)

    Aru, Violetta; Lam, Chloie; Khakimov, Bekzod

    2017-01-01

    Lipoproteins and their subfraction profiles have been associated to diverse diseases including Cardio Vascular Disease (CVD). There is thus a great demand for measuring and quantifying the lipoprotein profile in an efficient and accurate manner. Nuclear Magnetic Resonance (NMR) spectroscopy is un...

  2. Functional magnetic resonance imaging by visual stimulation

    International Nuclear Information System (INIS)

    Nishimura, Yukiko; Negoro, Kiyoshi; Morimatsu, Mitsunori; Hashida, Masahiro

    1996-01-01

    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)

  3. Evaluation of an Automated Analysis Tool for Prostate Cancer Prediction Using Multiparametric Magnetic Resonance Imaging.

    Directory of Open Access Journals (Sweden)

    Matthias C Roethke

    Full Text Available To evaluate the diagnostic performance of an automated analysis tool for the assessment of prostate cancer based on multiparametric magnetic resonance imaging (mpMRI of the prostate.A fully automated analysis tool was used for a retrospective analysis of mpMRI sets (T2-weighted, T1-weighted dynamic contrast-enhanced, and diffusion-weighted sequences. The software provided a malignancy prediction value for each image pixel, defined as Malignancy Attention Index (MAI that can be depicted as a colour map overlay on the original images. The malignancy maps were compared to histopathology derived from a combination of MRI-targeted and systematic transperineal MRI/TRUS-fusion biopsies.In total, mpMRI data of 45 patients were evaluated. With a sensitivity of 85.7% (with 95% CI of 65.4-95.0, a specificity of 87.5% (with 95% CI of 69.0-95.7 and a diagnostic accuracy of 86.7% (with 95% CI of 73.8-93.8 for detection of prostate cancer, the automated analysis results corresponded well with the reported diagnostic accuracies by human readers based on the PI-RADS system in the current literature.The study revealed comparable diagnostic accuracies for the detection of prostate cancer of a user-independent MAI-based automated analysis tool and PI-RADS-scoring-based human reader analysis of mpMRI. Thus, the analysis tool could serve as a detection support system for less experienced readers. The results of the study also suggest the potential of MAI-based analysis for advanced lesion assessments, such as cancer extent and staging prediction.

  4. Resting-state functional magnetic resonance imaging: the impact of regression analysis.

    Science.gov (United States)

    Yeh, Chia-Jung; Tseng, Yu-Sheng; Lin, Yi-Ru; Tsai, Shang-Yueh; Huang, Teng-Yi

    2015-01-01

    To investigate the impact of regression methods on resting-state functional magnetic resonance imaging (rsfMRI). During rsfMRI preprocessing, regression analysis is considered effective for reducing the interference of physiological noise on the signal time course. However, it is unclear whether the regression method benefits rsfMRI analysis. Twenty volunteers (10 men and 10 women; aged 23.4 ± 1.5 years) participated in the experiments. We used node analysis and functional connectivity mapping to assess the brain default mode network by using five combinations of regression methods. The results show that regressing the global mean plays a major role in the preprocessing steps. When a global regression method is applied, the values of functional connectivity are significantly lower (P ≤ .01) than those calculated without a global regression. This step increases inter-subject variation and produces anticorrelated brain areas. rsfMRI data processed using regression should be interpreted carefully. The significance of the anticorrelated brain areas produced by global signal removal is unclear. Copyright © 2014 by the American Society of Neuroimaging.

  5. Classification of multiple sclerosis patients by latent class analysis of magnetic resonance imaging characteristics.

    Science.gov (United States)

    Zwemmer, J N P; Berkhof, J; Castelijns, J A; Barkhof, F; Polman, C H; Uitdehaag, B M J

    2006-10-01

    Disease heterogeneity is a major issue in multiple sclerosis (MS). Classification of MS patients is usually based on clinical characteristics. More recently, a pathological classification has been presented. While clinical subtypes differ by magnetic resonance imaging (MRI) signature on a group level, a classification of individual MS patients based purely on MRI characteristics has not been presented so far. To investigate whether a restricted classification of MS patients can be made based on a combination of quantitative and qualitative MRI characteristics and to test whether the resulting subgroups are associated with clinical and laboratory characteristics. MRI examinations of the brain and spinal cord of 50 patients were scored for 21 quantitative and qualitative characteristics. Using latent class analysis, subgroups were identified, for whom disease characteristics and laboratory measures were compared. Latent class analysis revealed two subgroups that mainly differed in the extent of lesion confluency and MRI correlates of neuronal loss in the brain. Demographics and disease characteristics were comparable except for cognitive deficits. No correlations with laboratory measures were found. Latent class analysis offers a feasible approach for classifying subgroups of MS patients based on the presence of MRI characteristics. The reproducibility, longitudinal evolution and further clinical or prognostic relevance of the observed classification will have to be explored in a larger and independent sample of patients.

  6. Structural Image Analysis of the Brain in Neuropsychology Using Magnetic Resonance Imaging (MRI) Techniques.

    Science.gov (United States)

    Bigler, Erin D

    2015-09-01

    Magnetic resonance imaging (MRI) of the brain provides exceptional image quality for visualization and neuroanatomical classification of brain structure. A variety of image analysis techniques provide both qualitative as well as quantitative methods to relate brain structure with neuropsychological outcome and are reviewed herein. Of particular importance are more automated methods that permit analysis of a broad spectrum of anatomical measures including volume, thickness and shape. The challenge for neuropsychology is which metric to use, for which disorder and the timing of when image analysis methods are applied to assess brain structure and pathology. A basic overview is provided as to the anatomical and pathoanatomical relations of different MRI sequences in assessing normal and abnormal findings. Some interpretive guidelines are offered including factors related to similarity and symmetry of typical brain development along with size-normalcy features of brain anatomy related to function. The review concludes with a detailed example of various quantitative techniques applied to analyzing brain structure for neuropsychological outcome studies in traumatic brain injury.

  7. Directionality analysis on functional magnetic resonance imaging during motor task using Granger causality.

    Science.gov (United States)

    Anwar, A R; Muthalib, M; Perrey, S; Galka, A; Granert, O; Wolff, S; Deuschl, G; Raethjen, J; Heute, U; Muthuraman, M

    2012-01-01

    Directionality analysis of signals originating from different parts of brain during motor tasks has gained a lot of interest. Since brain activity can be recorded over time, methods of time series analysis can be applied to medical time series as well. Granger Causality is a method to find a causal relationship between time series. Such causality can be referred to as a directional connection and is not necessarily bidirectional. The aim of this study is to differentiate between different motor tasks on the basis of activation maps and also to understand the nature of connections present between different parts of the brain. In this paper, three different motor tasks (finger tapping, simple finger sequencing, and complex finger sequencing) are analyzed. Time series for each task were extracted from functional magnetic resonance imaging (fMRI) data, which have a very good spatial resolution and can look into the sub-cortical regions of the brain. Activation maps based on fMRI images show that, in case of complex finger sequencing, most parts of the brain are active, unlike finger tapping during which only limited regions show activity. Directionality analysis on time series extracted from contralateral motor cortex (CMC), supplementary motor area (SMA), and cerebellum (CER) show bidirectional connections between these parts of the brain. In case of simple finger sequencing and complex finger sequencing, the strongest connections originate from SMA and CMC, while connections originating from CER in either direction are the weakest ones in magnitude during all paradigms.

  8. The classification of benign and malignant human prostate tissue by multivariate analysis of {sup 1}H magnetic resonance spectra

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, P.; Smith, I.; Leboldus, L.; Littman, C.; Somorjai, L.; Bezabeh, T. [Institute for Biodiagnostic, National Research Council, Manitoba (Canada)

    1998-04-01

    {sup 1}H magnetic resonance spectroscopy studies (360 MHz) were performed on specimens of benign (n = 66) and malignant (n = 21) human prostate tissue from 50 patients and the spectral data were subjected to multivariate analysis, specifically linear-discriminant analysis. On the basis of histopathological assessments, an overall classification accuracy of 96.6 % was achieved, with a sensitivity of 100 % and a specificity of 95.5 % in classifying benign prostatic hyperplasia from prostatic cancer. Resonances due to citrate, glutamate, and taurine were among the six spectral subregions identified by our algorithm as having diagnostic potential. Significantly higher levels of citrate were observed in glandular than in stromal benign prostatic hyperplasia (P < 0.05). This method shows excellent promise for the possibility of in vivo assessment of prostate tissue by magnetic resonance. (author)

  9. Low field magnetic resonance imaging

    Science.gov (United States)

    Pines, Alexander; Sakellariou, Dimitrios; Meriles, Carlos A.; Trabesinger, Andreas H.

    2010-07-13

    A method and system of magnetic resonance imaging does not need a large homogenous field to truncate a gradient field. Spatial information is encoded into the spin magnetization by allowing the magnetization to evolve in a non-truncated gradient field and inducing a set of 180 degree rotations prior to signal acquisition.

  10. Parallel magnetic resonance imaging

    International Nuclear Information System (INIS)

    Larkman, David J; Nunes, Rita G

    2007-01-01

    Parallel imaging has been the single biggest innovation in magnetic resonance imaging in the last decade. The use of multiple receiver coils to augment the time consuming Fourier encoding has reduced acquisition times significantly. This increase in speed comes at a time when other approaches to acquisition time reduction were reaching engineering and human limits. A brief summary of spatial encoding in MRI is followed by an introduction to the problem parallel imaging is designed to solve. There are a large number of parallel reconstruction algorithms; this article reviews a cross-section, SENSE, SMASH, g-SMASH and GRAPPA, selected to demonstrate the different approaches. Theoretical (the g-factor) and practical (coil design) limits to acquisition speed are reviewed. The practical implementation of parallel imaging is also discussed, in particular coil calibration. How to recognize potential failure modes and their associated artefacts are shown. Well-established applications including angiography, cardiac imaging and applications using echo planar imaging are reviewed and we discuss what makes a good application for parallel imaging. Finally, active research areas where parallel imaging is being used to improve data quality by repairing artefacted images are also reviewed. (invited topical review)

  11. Noncontrast Magnetic Resonance Lymphography.

    Science.gov (United States)

    Arrivé, Lionel; Derhy, Sarah; El Mouhadi, Sanaâ; Monnier-Cholley, Laurence; Menu, Yves; Becker, Corinne

    2016-01-01

    Different imaging techniques have been used for the investigation of the lymphatic channels and lymph glands. Noncontrast magnetic resonance (MR) lymphography has significant advantages in comparison with other imaging modalities. Noncontrast MR lymphography uses very heavily T2-weighted fast spin echo sequences which obtain a nearly complete signal loss in tissue background and specific display of lymphatic vessels with a long T2 relaxation time. The raw data can be processed with different algorithms such as maximum intensity projection algorithm to obtain an anatomic representation. Standard T2-weighted MR images easily demonstrate the location of edema. It appears as subcutaneous infiltration of soft tissue with a classical honeycomb pattern. True collection around the muscular area may be demonstrated in case of severe lymphedema. Lymph nodes may be normal in size, number, and signal intensity; in other cases, lymph nodes may be smaller in size or number of lymph nodes may be restricted. MR lymphography allows a classification of lymphedema in aplasia (no collecting vessels demonstrated); hypoplasia (a small number of lymphatic vessels), and numerical hyperplasia or hyperplasia (with an increased number of lymphatic vessels of greater and abnormal diameter). Noncontrast MR lymphography is a unique noninvasive imaging modality for the diagnosis of lymphedema. It can be used for positive diagnosis, differential diagnosis, and specific evaluation of lymphedema severity. It may also be used for follow-up evaluation after treatment. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  12. Magnetic resonance imaging. 1

    International Nuclear Information System (INIS)

    Wall, E.E. van der; Roos, A.A. de; Doornbos, J.; Dijkman, P.R.M. van; Matheijssen, N.A.A.; Laarse, A. van der; Krauss, X.H.; Blokland, J.A.k.; Manger Cats, V.; Voorthuisen, A.E. van; Bruschke, A.V.G.

    1991-01-01

    The cardiovascular applications of MRI in coronary artery disease have considerably increased in recent years. Although many applications overlap those of other more cost-effective techniques, such as echocardiography, radionuclide angiography, and CT, MRI offers unique features not shared by the conventional techniques. Technical advantages are the excellent spatial resolution, the characterization of myocardial tissue, and the potential for three-dimensional imaging. This allows the accurate assessment of left ventricular mass and volume, the differentiation of infarcted tissue from normal myocardial tissue, and the determination of systolic wall thickening and regional wall motion abnormalities. Also inducible myocardial ischemia using pharmacological stress (dipyramidole or dobutamine) may be assessed by magnetic resonance imaging. Future technical developments include real-time imaging and noninvasive visualization of the coronary arteries. These advantages will have a major impact on the application of MRI in coronary artery disease, potentially unsurpassed by other techniques and certainly justifying the expenses. Consequently, the clinical use of MRI for the detection of coronary artery disease largely depends on the progress of technical developments. (author). 134 refs.; 10 figs.; 2 tabs

  13. 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

  14. 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

  15. Magnetic resonance colonography versus colonoscopy as a diagnostic investigation for colorectal cancer: a meta-analysis

    International Nuclear Information System (INIS)

    Purkayastha, S.; Tekkis, P.P.; Athanasiou, T.; Aziz, O.; Negus, R.; Gedroyc, W.; Darzi, A.W.

    2005-01-01

    AIMS: Magnetic resonance colonography (MRC) is emerging as a potential complementary investigation for the diagnosis of colorectal cancer (CRC) and also for benign pathology such as diverticular disease. A meta-analysis reporting the use of MRC is yet to be performed. The aim of this study was to evaluate the diagnostic accuracy of MRC compared with the gold-standard investigation, conventional colonoscopy (CC). METHODS: A literature search was carried out to identify studies containing comparative data between MRC findings and CC findings. Quantitative meta-analysis for diagnostic tests was performed, which included the calculation of independent sensitivities, specificities, diagnostic odds ratios, the construction of summary receiver operating characteristic (SROC) curves, pooled analysis and sensitivity analysis. The study heterogeneity was evaluated by the Q-test using a random-effect model to accommodate the cluster of outcomes between individual studies. RESULTS: In all, 8 comparative studies were identified, involving 563 patients. The calculated pooled sensitivity for all lesions was 75% (95% CI: 47% to 91%), the specificity was 96% (95% CI: 86% to 98%) and the area under the ROC curve was 90% (weighted). On sensitivity analysis, MRC had a better diagnostic accuracy for CRC than for polyps, with a sensitivity of 91% (95% CI: 97% to 91%), a specificity of 98% (95% CI: 66% to 99%) and an area under the ROC curve of 92%. There was no significant heterogeneity between the studies with regard to the diagnostic accuracy of MRC for CRC. CONCLUSION: This meta-analysis suggests that MRC is an imaging technique with high discrimination for cases presenting with colorectal cancer. The exact diagnostic role of MRC needs to be clarified (e.g. suitable for an elderly person with suspected CRC). Further evaluation is necessary to refine its applicability and diagnostic accuracy in comparison with other imaging methods such as computed tomography colonography

  16. Ultrasound versus magnetic resonance imaging for Morton neuroma: systematic review and meta-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Bignotti, Bianca; Martinoli, Carlo [University of Genoa, Radiology Department, Genoa, Genova (Italy); Signori, Alessio; Sormani, Maria Pia [University of Genoa, Institute of Statistics, Department of Health Sciences, Genoa (Italy); Molfetta, Luigi [University of Genoa, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics (DINOGMI), Genoa (Italy); Tagliafico, Alberto [University of Genoa, Institute of Anatomy, Department of Experimental Medicine, Genoa (Italy)

    2015-08-15

    To compare ultrasound (US) and magnetic resonance imaging (MRI) in the diagnosis of Morton's neuroma. Studies that assessed the diagnostic accuracy of US and MRI for Morton's neuroma were retrieved from major medical libraries independently by two reviewers up to 1 April 2014. Predefined inclusion and exclusion criteria were adopted. 277 studies were initially found, and the meta-analysis was conducted on 14 studies. US sensitivity was studied in five studies, MRI sensitivity in three studies, and both in six studies. All studies used surgery as the reference standard. A high sensitivity (SE) of diagnostic testing was observed for both US (SE (95 % CI) = 0.91 (0.83-0.96)) and MRI (SE (95 % CI) = 0.90 (0.82-0.96)) with no significant differences between the two modalities in diagnosis (Q test p = 0.88). For MRI, specificity of test was 1.00 with a pooled estimation of 1.00 (0.73-1.00), while the pooled specificity was 0.854 (95 % CI: 0.41-1.00) for US. No differences were observed between US and MRI in study design (p = 0.76). This meta-analysis shows that the SE of US (0.91) is equal to (p = 0.88) that of MRI (0.90) for identification of Morton's neuroma. (orig.)

  17. Phosphorus-31 NMR (nuclear magnetic resonance) analysis of gold plating baths

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R.E.

    1990-01-01

    This report describes the nuclear magnetic resonance (NMR) analysis of the gold plating baths in the Micro-Miniature Electronic Assembly department of Allied-Signal Inc., Kansas City Division (KCD). The baths were analyzed for phosphorylated components. In freshly prepared gold plating baths, a 50-percent aqueous solution of aminotrimethylphosphonate (ATMP) is the principal compound observed. As the bath is used in production, the ATMP breaks down and new materials (phosphate, ADMP, and AMMP) are identified. The NMR method was used to monitor the concentrations of the ATMP and breakdown products for a nine-month period. The 225-liter bath had plated approximately 100 square feet of gold during the nine-month period. These results can be used to predict the performance of baths as they are used in production. The accuracy of the analysis is 96 percent for ATMP and 92 percent for phosphate. The precision (relative standard deviation) is 5.2 percent for ATMP and 4.5 percent for phosphate. 1 ref., 5 figs., 2 tabs.

  18. 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 medical conditions. ...

  19. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... are the limitations of MRI of the Head? What is MRI of the Head? Magnetic resonance imaging ( ... brain) in routine clinical practice. top of page What are some common uses of the procedure? MR ...

  20. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... As the hydrogen atoms return to their usual alignment, they emit different amounts of energy that vary ... story about radiology? Share your patient story here Images × Image Gallery Radiologist prepping patient for magnetic resonance ...

  1. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... As the hydrogen atoms return to their usual alignment, they emit different amounts of energy that vary ... story about radiology? Share your patient story here Images × Image Gallery Magnetic Resonance Imaging (MRI) procedure View ...

  2. 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 ... the web pages found at these links. About Us | Contact Us | FAQ | Privacy | Terms of Use | Links | ...

  3. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... bear denotes child-specific content. Related Articles and Media Catheter Angiography Magnetic Resonance, Functional (fMRI) - Brain Children's ( ... the web pages found at these links. About Us | Contact Us | FAQ | Privacy | Terms of Use | Links | ...

  4. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... or thyroid problems. Any of these conditions may influence the decision on whether contrast material will be ... bear denotes child-specific content. Related Articles and Media Catheter Angiography Magnetic Resonance, Functional (fMRI) - Brain Children's ( ...

  5. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... it is useful to bring that to the attention of the technologist or scheduler before the exam. ... patient for magnetic resonance imaging (MRI) exam. View full size with caption Pediatric Content Some imaging tests ...

  6. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... it is useful to bring that to the attention of the scheduler before the exam and bring ... Image Gallery Magnetic Resonance Imaging (MRI) procedure View full size with caption Pediatric Content Some imaging tests ...

  7. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... MRI) exam. View full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media Catheter Angiography Magnetic Resonance, ...

  8. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... be necessary. Your doctor will explain the exact reason why another exam is requested. Sometimes a follow- ... necessary in trauma situations. Although there is no reason to believe that magnetic resonance imaging harms the ...

  9. 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...

  10. Comparative mass spectrometry & nuclear magnetic resonance metabolomic approaches for nutraceuticals quality control analysis: a brief review.

    Science.gov (United States)

    Farag, Mohamed A

    2014-01-01

    The number of botanical dietary supplements in the market has recently increased primarily due to increased health awareness. Standardization and quality control of the constituents of these plant extracts is an important topic, particularly when such ingredients are used long term as dietary supplements, or in cases where higher doses are marketed as drugs. The development of fast, comprehensive, and effective untargeted analytical methods for plant extracts is of high interest. Nuclear magnetic resonance spectroscopy and mass spectrometry are the most informative tools, each of which enables high-throughput and global analysis of hundreds of metabolites in a single step. Although only one of the two techniques is utilized in the majority of plant metabolomics applications, there is a growing interest in combining the data from both platforms to effectively unravel the complexity of plant samples. The application of combined MS and NMR in the quality control of nutraceuticals forms the major part of this review. Finally I will look at the future developments and perspectives of these two technologies for the quality control of herbal materials.

  11. Comparative analysis of Danggui and European Danggui using nuclear magnetic resonance-based metabolic fingerprinting.

    Science.gov (United States)

    Li, Zhen-Yu; Zhang, Zheng-Zheng; Du, Guan-Hua; Qin, Xue-Mei

    2015-01-25

    Danggui is a widely used herbal drug in traditional Chinese medicine, and adulteration with European Danggui is frequently encountered in the market. We compared the chemical compositions and biological effects of Danggui and European Danggui using proton nuclear magnetic resonance spectroscopy coupled with multivariate analysis. Results showed that Danggui and European Danggui differed in both primary and secondary metabolites. Danggui contained higher levels of alanine, γ-aminobutyrate, adenosine, arginine, sucrose, α-glucose, β-glucose, tryptophan, and cis-Z,Z'-3a.7a',7a.3a'-dihydroxyligustilide than European Danggui. Meanwhile, European Danggui contained higher contents of valine, proline, fumaric acid, phenylalanine, nicotinamide derivative, Z-butylidenephthalide, coniferyl ferulate, ferulic acid, Z-ligustilide, and Z,Z-6,6'7,3a-diligustilide than Danggui. A blood deficiency model was used to compare the biological effects of the two drugs. Despite its higher levels of Z-ligustilide and ferulic acid, European Danggui showed a weaker blood enriching effect than Danggui. Thus, the bioactive compounds responsible for the blood enriching effect in Danggui and their possible synergistic effects should be further studied. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Kinetic magnetic resonance imaging analysis of lumbar segmental mobility in patients without significant spondylosis.

    Science.gov (United States)

    Tan, Yanlin; Aghdasi, Bayan G; Montgomery, Scott R; Inoue, Hirokazu; Lu, Chang; Wang, Jeffrey C

    2012-12-01

    The purpose of this study was to examine lumbar segmental mobility using kinetic magnetic resonance imaging (MRI) in patients with minimal lumbar spondylosis. Mid-sagittal images of patients who underwent weight-bearing, multi-position kinetic MRI for symptomatic low back pain or radiculopathy were reviewed. Only patients with a Pfirrmann grade of I or II, indicating minimal disc disease, in all lumbar discs from L1-2 to L5-S1 were included for further analysis. Translational and angular motion was measured at each motion segment. The mean translational motion of the lumbar spine at each level was 1.38 mm at L1-L2, 1.41 mm at L2-L3, 1.14 mm at L3-L4, 1.10 mm at L4-L5 and 1.01 mm at L5-S1. Translational motion at L1-L2 and L2-L3 was significantly greater than L3-4, L4-L5 and L5-S1 levels (P lumbar spine was highest at L2-L3 (22.45 %) and least at L5/S1 (14.71 %) (P lumbar segmental mobility in patients without significant degenerative disc disease and found that translational motion was greatest in the proximal lumbar levels whereas angular motion was similar in the mid-lumbar levels but decreased at L1-L2 and L5-S1.

  13. A medical software system for volumetric analysis of cerebral pathologies in magnetic resonance imaging (MRI) data.

    Science.gov (United States)

    Egger, Jan; Kappus, Christoph; Freisleben, Bernd; Nimsky, Christopher

    2012-08-01

    In this contribution, a medical software system for volumetric analysis of different cerebral pathologies in magnetic resonance imaging (MRI) data is presented. The software system is based on a semi-automatic segmentation algorithm and helps to overcome the time-consuming process of volume determination during monitoring of a patient. After imaging, the parameter settings-including a seed point-are set up in the system and an automatic segmentation is performed by a novel graph-based approach. Manually reviewing the result leads to reseeding, adding seed points or an automatic surface mesh generation. The mesh is saved for monitoring the patient and for comparisons with follow-up scans. Based on the mesh, the system performs a voxelization and volume calculation, which leads to diagnosis and therefore further treatment decisions. The overall system has been tested with different cerebral pathologies-glioblastoma multiforme, pituitary adenomas and cerebral aneurysms- and evaluated against manual expert segmentations using the Dice Similarity Coefficient (DSC). Additionally, intra-physician segmentations have been performed to provide a quality measure for the presented system.

  14. Hippocampus shape analysis for temporal lobe epilepsy detection in magnetic resonance imaging

    Science.gov (United States)

    Kohan, Zohreh; Azmi, Reza

    2016-03-01

    There are evidences in the literature that Temporal Lobe Epilepsy (TLE) causes some lateralized atrophy and deformation on hippocampus and other substructures of the brain. Magnetic Resonance Imaging (MRI), due to high-contrast soft tissue imaging, is one of the most popular imaging modalities being used in TLE diagnosis and treatment procedures. Using an algorithm to help clinicians for better and more effective shape deformations analysis could improve the diagnosis and treatment of the disease. In this project our purpose is to design, implement and test a classification algorithm for MRIs based on hippocampal asymmetry detection using shape and size-based features. Our method consisted of two main parts; (1) shape feature extraction, and (2) image classification. We tested 11 different shape and size features and selected four of them that detect the asymmetry in hippocampus significantly in a randomly selected subset of the dataset. Then, we employed a support vector machine (SVM) classifier to classify the remaining images of the dataset to normal and epileptic images using our selected features. The dataset contains 25 patient images in which 12 cases were used as a training set and the rest 13 cases for testing the performance of classifier. We measured accuracy, specificity and sensitivity of, respectively, 76%, 100%, and 70% for our algorithm. The preliminary results show that using shape and size features for detecting hippocampal asymmetry could be helpful in TLE diagnosis in MRI.

  15. Magnetic Resonance Imaging (MRI) Analysis of Fibroid Location in Women Achieving Pregnancy After Uterine Artery Embolization

    International Nuclear Information System (INIS)

    Walker, Woodruff J.; Bratby, Mark John

    2007-01-01

    The purpose of this study was to evaluate the fibroid morphology in a cohort of women achieving pregnancy following treatment with uterine artery embolization (UAE) for symptomatic uterine fibroids. A retrospective review of magnetic resonance imaging (MRI) of the uterus was performed to assess pre-embolization fibroid morphology. Data were collected on fibroid size, type, and number and included analysis of follow-up imaging to assess response. There have been 67 pregnancies in 51 women, with 40 live births. Intramural fibroids were seen in 62.7% of the women (32/48). Of these the fibroids were multiple in 16. A further 12 women had submucosal fibroids, with equal numbers of types 1 and 2. Two of these women had coexistent intramural fibroids. In six women the fibroids could not be individually delineated and formed a complex mass. All subtypes of fibroid were represented in those subgroups of women achieving a live birth versus those who did not. These results demonstrate that the location of uterine fibroids did not adversely affect subsequent pregnancy in the patient population investigated. Although this is only a small qualitative study, it does suggest that all types of fibroids treated with UAE have the potential for future fertility

  16. Improved application of independent component analysis to functional magnetic resonance imaging study via linear projection techniques.

    Science.gov (United States)

    Long, Zhiying; Chen, Kewei; Wu, Xia; Reiman, Eric; Peng, Danling; Yao, Li

    2009-02-01

    Spatial Independent component analysis (sICA) has been widely used to analyze functional magnetic resonance imaging (fMRI) data. The well accepted implicit assumption is the spatially statistical independency of intrinsic sources identified by sICA, making the sICA applications difficult for data in which there exist interdependent sources and confounding factors. This interdependency can arise, for instance, from fMRI studies investigating two tasks in a single session. In this study, we introduced a linear projection approach and considered its utilization as a tool to separate task-related components from two-task fMRI data. The robustness and feasibility of the method are substantiated through simulation on computer data and fMRI real rest data. Both simulated and real two-task fMRI experiments demonstrated that sICA in combination with the projection method succeeded in separating spatially dependent components and had better detection power than pure model-based method when estimating activation induced by each task as well as both tasks.

  17. Magnetic Resonance Imaging. Chapter 15

    Energy Technology Data Exchange (ETDEWEB)

    Leach, M. O. [The Institute of Cancer Research and The Royal Marsden Hospital, London (United Kingdom)

    2014-09-15

    In Chapter 14, the principles of nuclear magnetic resonance were presented, along with an introduction to image forming processes. In this chapter, magnetic resonance imaging (MRI) will be reviewed, beginning with the hardware needed and its impact on image quality. The acquisition processes and image reconstruction will be discussed, as well as the artefacts that are possible, with discussion of the important area of safety and bioeffects completing the chapter.

  18. 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.

  19. Immediate analysis of the oil content of seeds by carbon-13 nuclear magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Leal, K Z; Costa, V E.U.; Seidl, P R; Campos, M P.A.; Colnago, L A [Instituto Militar de Engenharia, Rio de Janeiro (Brazil). Secao de Quimica

    1981-11-01

    The carbon 13 nuclear magnetic resonance (CMR) spectra of a series of Brazilian oilseeds was registered. The main constituents of the oils are identified and signals for each carbon atom are assigned. Chemical shifts are estimated for the free fatty acids and compared to those observed from the seeds, with good results. Besides being non-destructive, the RMC method proves to be fast and is useful in the determination of the principal components of the oil fraction of different types of seeds.

  20. Nuclear magnetic resonance diagnostic apparatus

    International Nuclear Information System (INIS)

    Sugimoto, H.

    1985-01-01

    Nuclear magnetic resonance diagnostic apparatus including a coil for generating a gradient field in a plane perpendicular to a static magnetic field, means for controlling the operation of the coil to rotationally shift in angular steps the gradient direction of the gradient field at an angle pitch of some multiple of the unit index angle through a plurality of rotations to assume all the shift positions of the gradient direction, a rough image reconstructor for reconstructing a rough tomographic image on the basis of nuclear magnetic resonance signals acquired during a rotation of the second gradient magnetic field, a rough image display for depicting the rough tomographic image, a final image reconstructor for reconstructing a final tomographic image on the basis of all nuclear magnetic resonance signals corresponding to all of the expected rotation shift positions acquired during a plurality of rotations and a final image display for depicting the final tomographic image

  1. Nuclear magnetic resonance and earth magnetic field

    International Nuclear Information System (INIS)

    Anon.

    1998-01-01

    Nuclear magnetic resonance concerns nuclei whose spin is different from 0. These nuclei exposed to a magnetic field is comparable to a peg top spinning around its axis while being moved by a precession movement called Larmor precession. This article presents an experiment whose aim is to reveal nuclear magnetism of nuclei by observing Larmor precession phenomena due to the earth magnetic field. The earth magnetic field being too weak, it is necessary to increase the magnetization of the sample during a polarization phase. First the sample is submitted to a magnetic field B perpendicular to the earth magnetic field B 0 , then B is cut off and the nuclei move back to their equilibrium position by executing a precession movement due to B 0 field. (A.C.)

  2. Magnetic Resonance Imaging

    Science.gov (United States)

    ... Permanent cosmetics or tattoos Dentures/teeth with magnetic keepers Other implants that involve magnets Medication patch (i. ... or longer. You’ll be told ahead of time just how long your scan is expected to ...

  3. Analysis and Optimization of Four-Coil Planar Magnetically Coupled Printed Spiral Resonators

    Directory of Open Access Journals (Sweden)

    Sadeque Reza Khan

    2016-08-01

    Full Text Available High-efficiency power transfer at a long distance can be efficiently established using resonance-based wireless techniques. In contrast to the conventional two-coil-based inductive links, this paper presents a magnetically coupled fully planar four-coil printed spiral resonator-based wireless power-transfer system that compensates the adverse effect of low coupling and improves efficiency by using high quality-factor coils. A conformal architecture is adopted to reduce the transmitter and receiver sizes. Both square architecture and circular architectures are analyzed and optimized to provide maximum efficiency at a certain operating distance. Furthermore, their performance is compared on the basis of the power-transfer efficiency and power delivered to the load. Square resonators can produce higher measured power-transfer efficiency (79.8% than circular resonators (78.43% when the distance between the transmitter and receiver coils is 10 mm of air medium at a resonant frequency of 13.56 MHz. On the other hand, circular coils can deliver higher power (443.5 mW to the load than the square coils (396 mW under the same medium properties. The performance of the proposed structures is investigated by simulation using a three-layer human-tissue medium and by experimentation.

  4. Analysis and Optimization of Four-Coil Planar Magnetically Coupled Printed Spiral Resonators.

    Science.gov (United States)

    Khan, Sadeque Reza; Choi, GoangSeog

    2016-08-03

    High-efficiency power transfer at a long distance can be efficiently established using resonance-based wireless techniques. In contrast to the conventional two-coil-based inductive links, this paper presents a magnetically coupled fully planar four-coil printed spiral resonator-based wireless power-transfer system that compensates the adverse effect of low coupling and improves efficiency by using high quality-factor coils. A conformal architecture is adopted to reduce the transmitter and receiver sizes. Both square architecture and circular architectures are analyzed and optimized to provide maximum efficiency at a certain operating distance. Furthermore, their performance is compared on the basis of the power-transfer efficiency and power delivered to the load. Square resonators can produce higher measured power-transfer efficiency (79.8%) than circular resonators (78.43%) when the distance between the transmitter and receiver coils is 10 mm of air medium at a resonant frequency of 13.56 MHz. On the other hand, circular coils can deliver higher power (443.5 mW) to the load than the square coils (396 mW) under the same medium properties. The performance of the proposed structures is investigated by simulation using a three-layer human-tissue medium and by experimentation.

  5. Noble gas magnetic resonator

    Science.gov (United States)

    Walker, Thad Gilbert; Lancor, Brian Robert; Wyllie, Robert

    2014-04-15

    Precise measurements of a precessional rate of noble gas in a magnetic field is obtained by constraining the time averaged direction of the spins of a stimulating alkali gas to lie in a plane transverse to the magnetic field. In this way, the magnetic field of the alkali gas does not provide a net contribution to the precessional rate of the noble gas.

  6. Algorithms for the Analysis of 3D Magnetic Resonance Angiography Images

    International Nuclear Information System (INIS)

    Tizon, Xavier

    2004-01-01

    Atherosclerosis is a disease of the arterial wall, progressively impairing blood flow as it spreads throughout the body. The heart attacks and strokes that result of this condition cause more deaths than cancer in industrial countries. Angiography refers to the group of imaging techniques used through the diagnosis, treatment planning and follow-up of atherosclerosis. In recent years, Magnetic Resonance Angiography (MRA) has shown promising abilities to supplant conventional, invasive, X-ray-based angiography. In order to fully benefit from this modality, there is a need for more objective and reproducible methods. This thesis shows, in two applications, how computerized image analysis can help define and implement these methods. First, by using segmentation to improve visualization of blood-pool contrast enhanced (CE)-MRA, with an additional application in coronary Computerized Tomographic Angiography. We show that, using a limited amount of user interaction and an algorithmic framework borrowed from graph theory and fuzzy logic theory, we can simplify the display of complex 3D structures like vessels. Second, by proposing a methodology to analyze the geometry of arteries in whole-body CE-MRA. The vessel centreline is extracted, and geometrical properties of this 3D curve are measured, to improve interpretation of the angiograms. It represents a more global approach than the conventional evaluation of atherosclerosis, as a first step towards screening for vascular diseases. We have developed the methods presented in this thesis with clinical practice in mind. However, they have the potential to be useful to other applications of computerized image analysis

  7. In Vivo Imaging of Tau Pathology Using Magnetic Resonance Imaging Textural Analysis

    Directory of Open Access Journals (Sweden)

    Niall Colgan

    2017-11-01

    Full Text Available Background: Non-invasive characterization of the pathological features of Alzheimer's disease (AD could enhance patient management and the development of therapeutic strategies. Magnetic resonance imaging texture analysis (MRTA has been used previously to extract texture descriptors from structural clinical scans in AD to determine cerebral tissue heterogeneity. In this study, we examined the potential of MRTA to specifically identify tau pathology in an AD mouse model and compared the MRTA metrics to histological measures of tau burden.Methods: MRTA was applied to T2 weighted high-resolution MR images of nine 8.5-month-old rTg4510 tau pathology (TG mice and 16 litter matched wild-type (WT mice. MRTA comprised of the filtration-histogram technique, where the filtration step extracted and enhanced features of different sizes (fine, medium, and coarse texture scales, followed by quantification of texture using histogram analysis (mean gray level intensity, mean intensity, entropy, uniformity, skewness, standard-deviation, and kurtosis. MRTA was applied to manually segmented regions of interest (ROI drawn within the cortex, hippocampus, and thalamus regions and the level of tau burden was assessed in equivalent regions using histology.Results: Texture parameters were markedly different between WT and TG in the cortex (E, p < 0.01, K, p < 0.01, the hippocampus (K, p < 0.05 and in the thalamus (K, p < 0.01. In addition, we observed significant correlations between histological measurements of tau burden and kurtosis in the cortex, hippocampus and thalamus.Conclusions: MRTA successfully differentiated WT and TG in brain regions with varying degrees of tau pathology (cortex, hippocampus, and thalamus based on T2 weighted MR images. Furthermore, the kurtosis measurement correlated with histological measures of tau burden. This initial study indicates that MRTA may have a role in the early diagnosis of AD and the assessment of tau pathology using

  8. Nontargeted nuclear magnetic resonance (NMR) analysis to detect hazardous substances including methanol in unrecorded alcohol from Novosibirsk, Russia

    OpenAIRE

    Hausler, Thomas; Okaru,  Alex O.; Neufeld, Maria; Rehm, Jürgen; Kuballa, Thomas; Luy, Burkhard; Lachenmeier, Dirk W.

    2016-01-01

    Nuclear magnetic resonance (NMR) spectroscopy was applied to the analysis of alcoholic products in the context of health and safety control. A total of 86 samples of unrecorded alcohol were collected in Novosibirsk and nearby cities in Russia. Sampling was based on interviews with alcohol dependent patients, and unrecorded alcohol thus defined included illegally or informally produced alcoholic products (e.g., counterfeit or home-made alcoholic beverages) or surrogate alcohol in the form of c...

  9. Methods of Blood Oxygen Level-Dependent Magnetic Resonance Imaging Analysis for Evaluating Renal Oxygenation

    Directory of Open Access Journals (Sweden)

    Fen Chen

    2018-03-01

    Full Text Available Blood oxygen level-dependent magnetic resonance imaging (BOLD MRI has recently been utilized as a noninvasive tool for evaluating renal oxygenation. Several methods have been proposed for analyzing BOLD images. Regional ROI selection is the earliest and most widely used method for BOLD analysis. In the last 20 years, many investigators have used this method to evaluate cortical and medullary oxygenation in patients with ischemic nephropathy, hypertensive nephropathy, diabetic nephropathy, chronic kidney disease (CKD, acute kidney injury and renal allograft rejection. However, clinical trials of BOLD MRI using regional ROI selection revealed that it was difficult to distinguish the renal cortico-medullary zones with this method, and that it was susceptible to observer variability. To overcome these deficiencies, several new methods were proposed for analyzing BOLD images, including the compartmental approach, fractional hypoxia method, concentric objects (CO method and twelve-layer concentric objects (TLCO method. The compartmental approach provides an algorithm to judge whether the pixel belongs to the cortex or medulla. Fractional kidney hypoxia, measured by using BOLD MRI, was negatively correlated with renal blood flow, tissue perfusion and glomerular filtration rate (GFR in patients with atherosclerotic renal artery stenosis. The CO method divides the renal parenchyma into six or twelve layers of thickness in each coronal slice of BOLD images and provides a R2* radial profile curve. The slope of the R2* curve associated positively with eGFR in CKD patients. Indeed, each method invariably has advantages and disadvantages, and there is generally no consensus method so far. Undoubtedly, analytic approaches for BOLD MRI with better reproducibility would assist clinicians in monitoring the degree of kidney hypoxia and thus facilitating timely reversal of tissue hypoxia.

  10. A feasibility study of hand kinematics for EVA analysis using magnetic resonance imaging

    Science.gov (United States)

    Dickenson, Rueben D.; Lorenz, Christine H.; Peterson, Steven W.; Strauss, Alvin M.; Main, John A.

    1992-01-01

    A new method of analyzing the kinematics of joint motion is developed. Magnetic Resonance Imaging (MRI) offers several distinct advantages. Past methods of studying anatomic joint motion have usually centered on four approaches. These methods are x-ray projection, goniometric linkage analysis, sonic digitization, and landmark measurement of photogrammetry. Of these four, only x-ray is applicable for in vivo studies. The remaining three methods utilize other types of projections of inter-joint measurements, which can cause various types of error. MRI offers accuracy in measurement due to its tomographic nature (as opposed to projection) without the problems associated with x-ray dosage. Once the data acquisition of MR images was complete, the images were processed using a 3D volume rendering workstation. The metacarpalphalangeal (MCP) joint of the left index finger was selected and reconstructed into a three-dimensional graphic display. From the reconstructed volumetric images, measurements of the angles of movement of the applicable bones were obtained and processed by analyzing the screw motion of the MCP joint. Landmark positions were chosen at distinctive locations of the joint at fixed image threshold intensity levels to ensure repeatability. The primarily two dimensional planar motion of this joint was then studied using a method of constructing coordinate systems using three (or more) points. A transformation matrix based on a world coordinate system described the location and orientation of a local target coordinate system. Future research involving volume rendering of MRI data focusing on the internal kinematics of the hand's individual ligaments, cartilage, tendons, etc. will follow. Its findings will show the applicability of MRI to joint kinematics for gaining further knowledge of the hand-glove (power assisted) design for extravehicular activity (EVA).

  11. Magnetic resonance cholangiopancreatography in the diagnosis of pancreas divisum: a systematic review and meta-analysis.

    Science.gov (United States)

    Rustagi, Tarun; Njei, Basile

    2014-08-01

    This study aimed to perform a structured meta-analysis of all eligible studies to assess the overall diagnostic use of magnetic resonance cholangiopancreatography (MRCP) alone or with secretin enhancement (secretin-enhanced MRCP [S-MRCP]) in the detection of pancreas divisum. Two authors independently performed a comprehensive search of PubMed, MEDLINE, and the Cochrane Library from inception to September 2013. Studies were included if they allowed construction of 2 × 2 contingency tables of MRCP and/or S-MRCP compared with criterion standard. DerSimonian-Laird random effect models were used to estimate the pooled sensitivity, specificity, specificity, and quantitative receiver operating characteristics. Of 51 citations, 10 studies with 1474 patients were included. Secretin-enhanced MRCP had a higher overall diagnostic performance than MRCP (S-MRCP: pooled sensitivity, 86% [95% confidence interval (CI), 77%-93%]; specificity, 97% [95% CI, 94%-99%]; and area under the curve, 0.93 ± 0.056 compared with MRCP: sensitivity, 52% [95% CI, 45%-59%]; specificity, 97% [95% CI, 94%-99%]; and area under the curve, 0.76 ± 0.104). Pooled diagnostic odds ratios were 72.19 (95% CI, 5.66-938.8) and 23.39 (95% CI, 7.93-69.02) for S-MRCP and MRCP, respectively. Visual inspection of the funnel plot showed low potential for publication bias. Secretin-enhanced MRCP has a much higher diagnostic accuracy than MRCP and should be preferred for diagnosis of pancreas divisum.

  12. Absolute quantitative analysis for sorbic acid in processed foods using proton nuclear magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Ohtsuki, Takashi; Sato, Kyoko; Sugimoto, Naoki; Akiyama, Hiroshi; Kawamura, Yoko

    2012-01-01

    Highlights: ► A method using qHNMR was applied and validated to determine SA in processed foods. ► This method has good accuracy, precision, selectiveness, and linearity. ► The proposed method is more rapid and simple than the conventional method. ► We found that the proposed method is reliable for the accurate determination of SA. ► This method can be used for the monitoring of SA in processed foods. - Abstract: An analytical method using solvent extraction and quantitative proton nuclear magnetic resonance (qHNMR) spectroscopy was applied and validated for the absolute quantification of sorbic acid (SA) in processed foods. The proposed method showed good linearity. The recoveries for samples spiked at the maximum usage level specified for food in Japan and at 0.13 g kg −1 (beverage: 0.013 g kg −1 ) were larger than 80%, whereas those for samples spiked at 0.063 g kg −1 (beverage: 0.0063 g kg −1 ) were between 56.9 and 83.5%. The limit of quantification was 0.063 g kg −1 for foods (and 0.0063 g kg −1 for beverages containing Lactobacillus species). Analysis of the SA content of commercial processed foods revealed quantities equal to or greater than those measured using conventional steam-distillation extraction and high-performance liquid chromatography quantification. The proposed method was rapid, simple, accurate, and precise, and provided International System of Units traceability without the need for authentic analyte standards. It could therefore be used as an alternative to the quantification of SA in processed foods using conventional method.

  13. Absolute quantitative analysis for sorbic acid in processed foods using proton nuclear magnetic resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ohtsuki, Takashi, E-mail: ohtsuki@nihs.go.jp [National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501 (Japan); Sato, Kyoko; Sugimoto, Naoki; Akiyama, Hiroshi; Kawamura, Yoko [National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501 (Japan)

    2012-07-13

    Highlights: Black-Right-Pointing-Pointer A method using qHNMR was applied and validated to determine SA in processed foods. Black-Right-Pointing-Pointer This method has good accuracy, precision, selectiveness, and linearity. Black-Right-Pointing-Pointer The proposed method is more rapid and simple than the conventional method. Black-Right-Pointing-Pointer We found that the proposed method is reliable for the accurate determination of SA. Black-Right-Pointing-Pointer This method can be used for the monitoring of SA in processed foods. - Abstract: An analytical method using solvent extraction and quantitative proton nuclear magnetic resonance (qHNMR) spectroscopy was applied and validated for the absolute quantification of sorbic acid (SA) in processed foods. The proposed method showed good linearity. The recoveries for samples spiked at the maximum usage level specified for food in Japan and at 0.13 g kg{sup -1} (beverage: 0.013 g kg{sup -1}) were larger than 80%, whereas those for samples spiked at 0.063 g kg{sup -1} (beverage: 0.0063 g kg{sup -1}) were between 56.9 and 83.5%. The limit of quantification was 0.063 g kg{sup -1} for foods (and 0.0063 g kg{sup -1} for beverages containing Lactobacillus species). Analysis of the SA content of commercial processed foods revealed quantities equal to or greater than those measured using conventional steam-distillation extraction and high-performance liquid chromatography quantification. The proposed method was rapid, simple, accurate, and precise, and provided International System of Units traceability without the need for authentic analyte standards. It could therefore be used as an alternative to the quantification of SA in processed foods using conventional method.

  14. Fourier transform nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Geick, R.

    1981-01-01

    This review starts with the basic principles of resonance phenomena in physical systems. Especially, the connection is shown between the properties of these systems and Fourier transforms. Next, we discuss the principles of nuclear magnetic resonance. Starting from the general properties of physical systems showing resonance phenomena and from the special properties of nuclear spin systems, the main part of this paper reviews pulse and Fourier methods in nuclear magnetic resonance. Among pulse methods, an introduction will be given to spin echoes, and, apart from the principle of Fourier transform nuclear magnetic resonance, an introduction to the technical problems of this method, e.g. resolution in the frequency domain, aliasing, phase and intensity errors, stationary state of the spin systems for repetitive measurements, proton decoupling, and application of Fourier methods to systems in a nonequilibrium state. The last section is devoted to special applications of Fourier methods and recent developments, e.g. measurement of relaxation times, solvent peak suppression, 'rapid scan'-method, methods for suppressing the effects of dipolar coupling in solids, two-dimensional Fourier transform nuclear magnetic resonance, and spin mapping or zeugmatography. (author)

  15. 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.

  16. Principles of magnetic resonance imaging

    International Nuclear Information System (INIS)

    Mlynarik, V.; Tkac, I.; Srbecky, M.

    1995-01-01

    The aim of this review is to describe and explain the basic principles of magnetic resonance imaging. The first part of the text is devoted to the phenomenon of magnetic resonance (the interaction of RF magnetic field with the set of magnetic moments in the homogeneous magnetic field) and to relaxation processes. Then, the creation of MR image is described (slice selection, phase and frequency encoding of spatial information). The basic and the most frequently used techniques are explained (spin echo, gradient echo). The way the repetition and echo times influence the image quality and contrast (T1 or T2 weighing) is described. The part with the technical description of the MR equipment is included in the review. The MR imagination examination are compared with X-ray computer tomography technique

  17. Immediate analysis of the oil content of seeds by carbon-13 nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Leal, K.Z.; Costa, V.E.U.; Seidl, P.R.; Campos, M.P.A.; Colnago, L.A.

    1981-01-01

    The carbon 13 nuclear magnetic resonance (CMR) spectra of a series of Brazilian oilseeds was registered. The main constituents of the oils are identified and signals for each carbon atom are assigned. Chemical shifts are estimated for the free fatty acids and compared to those observed from the seeds, with good results. Besides being non-destructive, the RMC method proves to be fast and is useful in the determination of the principal components of the oil fraction of different types of seeds. (Author) [pt

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

    KAUST Repository

    Fridjonsson, Einar Orn; Creber, Sarah A.; Vrouwenvelder, Johannes S.; Johns, Michael L.

    2015-01-01

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

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

    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.

  20. Nuclear magnetic resonance analysis of freeze-thaw damage in natural pumice concrete

    Directory of Open Access Journals (Sweden)

    Wang, Xiaoxiao

    2016-06-01

    Full Text Available This paper presents an analysis of the damage propagation features of the pore structure of natural pumice lightweight aggregate concrete (LWC under freeze-thaw cyclic action. After freeze-thaw cycling, we conducted nuclear magnetic resonance (NMR tests on the concrete and acquired the porosity, distribution of transverse relaxation time T2, and magnetic resonance imaging (MRI results. The results showed the following. The T2 distribution of the LWC prior to freeze-thaw cycling presented four peaks representative of a preponderance of small pores. After 50, 100, 150, and 200 freeze-thaw cycles, the total area of the T2 spectrum and the porosity increased significantly. The MRI presented the changing spatial distribution of pores within the LWC during freeze-thaw cycling. Ultrasonic testing technology was applied simultaneously to analyze the NMR results, which verified that the new NMR technology demonstrated high accuracy and practicability for research regarding freeze-thaw concrete damage.En este trabajo se analiza la propagación de los daños que se producen en la estructura porosa de hormigón aligerado a base de piedra pómez natural sometido a la acción cíclica de hielo-deshielo. Después de realizarse los ensayos de hielo-deshielo, el hormigón se analizó mediante resonancia magnética nuclear (RMN, determinándose la porosidad y la distribución del tiempo de relajación transversal, T2, y registrándose las imágenes captadas por resonancia magnética. De acuerdo con los resultados obtenidos, antes de los ciclos de hielo-deshielo la distribución de T2 del hormigón aligerado presentaba cuatro picos, indicativos de un predominio de poros pequeños. Después de que se sometiera a 50, 100, 150, y 200 ciclos, se observó un aumento importante tanto de la porosidad como de la superficie total del espectro de T2. Las imágenes captadas por resonancia magnética evidenciaron la modificación de la distribución espacial de los poros del

  1. Recommendations concerning magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    1986-01-01

    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: 31 P, 13 C, 1 H (and possibly 19 F and 23 Na). 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.)

  2. Migraine and magnetic resonance spectroscopy

    DEFF Research Database (Denmark)

    Younis, Samaira; Hougaard, Anders; Vestergaard, Mark B.

    2017-01-01

    Purpose of review: To present an updated and streamlined overview of the metabolic and biochemical aspect of the migraine pathophysiology based on findings from phosphorous (31P) and hydrogen (1H) magnetic resonance spectroscopy (MRS) studies. Recent findings: Despite of the variation in the meth......Purpose of review: To present an updated and streamlined overview of the metabolic and biochemical aspect of the migraine pathophysiology based on findings from phosphorous (31P) and hydrogen (1H) magnetic resonance spectroscopy (MRS) studies. Recent findings: Despite of the variation...

  3. Analysis of the brain proton magnetic resonance spectroscopy - differences between normal grey and white matter

    International Nuclear Information System (INIS)

    Krukowski, P.; Podgorski, P.; Guzinski, M.; Szewczyk, P.; Sasiadek, M.

    2010-01-01

    Background: The proton magnetic resonance spectroscopy (HMRS) is a non-invasive diagnostic method that allows for an assessment of the metabolite concentration in tissues. The sources of the strongest resonance signals within the brain are N-acetylaspartate (NAA), creatine (Cr), choline (Cho), myoinositol (mI) and water. The aim of our study was to analyse the ratios of metabolite signals within the brain in HMRS in the healthy population, to define the differences between the grey and white matter spectra. Material/Methods: We studied prospectively 90 subjects aged from 8 to 80 years (mean 43.3 years, SD=17.9), without neurological symptoms or abnormalities in magnetic resonance imaging. In all patients, brain HMRS with Signa HDx 1.5 T MR unit (GE Healthcare) was performed with PRESS sequence, using a single voxel method, at TE of 35 ms and TR of 1500 ms. Spectroscopic evaluation involved voxels placed in the white matter of parietal lobe (PWM) and the grey matter of posterior cingulate gyrus (PGM). On the basis of the intensity of NAA, Cr, Cho, mI and water signals, the proportions of these signals were calculated, as well as the ratio of the analyzed metabolite signal to the sum of signals of NAA, Cho, Cr and mI (%Met) in the PGM and PWM voxels. We compared the proportions in the same patients in PGM and PWM voxels. Results: There has been a statistically significant difference between the proportions of a majority of the metabolite ratios evaluated in PGM and PWM, indicating the higher concentration of NAA, Cr and mI in grey matter, and higher concentration of Cho in white matter. Conclusions: HMRS spectra of the brain grey and white matter differ significantly. The concentrations of NAA, Cr and mI are higher in grey matter, while of choline - in the white matter. (authors)

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

    International Nuclear Information System (INIS)

    Costa, Flavia Martins; Setti, Marcela; Vianna, Evandro Miguelote; Domingues, Romulo Cortes; Meohas, Walter; Rezende, Jose Francisco; Gasparetto, Emerson Leandro

    2009-01-01

    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)

  5. Statistical Methods for Magnetic Resonance Image Analysis with Applications to Multiple Sclerosis

    Science.gov (United States)

    Pomann, Gina-Maria

    Multiple sclerosis (MS) is an immune-mediated neurological disease that causes disability and morbidity. In patients with MS, the accumulation of lesions in the white matter of the brain is associated with disease progression and worse clinical outcomes. In the first part of the dissertation, we present methodology to study to compare the brain anatomy between patients with MS and controls. A nonparametric testing procedure is proposed for testing the null hypothesis that two samples of curves observed at discrete grids and with noise have the same underlying distribution. We propose to decompose the curves using functional principal component analysis of an appropriate mixture process, which we refer to as marginal functional principal component analysis. This approach reduces the dimension of the testing problem in a way that enables the use of traditional nonparametric univariate testing procedures. The procedure is computationally efficient and accommodates different sampling designs. Numerical studies are presented to validate the size and power properties of the test in many realistic scenarios. In these cases, the proposed test is more powerful than its primary competitor. The proposed methodology is illustrated on a state-of-the art diffusion tensor imaging study, where the objective is to compare white matter tract profiles in healthy individuals and MS patients. In the second part of the thesis, we present methods to study the behavior of MS in the white matter of the brain. Breakdown of the blood-brain barrier in newer lesions is indicative of more active disease-related processes and is a primary outcome considered in clinical trials of treatments for MS. Such abnormalities in active MS lesions are evaluated in vivo using contrast-enhanced structural magnetic resonance imaging (MRI), during which patients receive an intravenous infusion of a costly magnetic contrast agent. In some instances, the contrast agents can have toxic effects. Recently, local

  6. Hyperfine structure analysis in magnetic resonance spectroscopy: from astrophysical measurements towards endogenous biosensors in human tissue

    International Nuclear Information System (INIS)

    Schroeder, L.; California Univ., Berkeley, CA; Lawrence Berkeley National Lab., Berkeley, CA

    2007-01-01

    The hyperfine interaction of two spins is a well studied effect in atomic systems. Magnetic resonance experiments demonstrate that the detectable dipole transitions are determined by the magnetic moments of the constituents and the external magnetic field. Transferring the corresponding quantum mechanics to molecular bound nuclear spins allows for precise prediction of NMR spectra obtained from metabolites in human tissue. This molecular hyperfine structure has been neglected so far in in vivo NMR spectroscopy but contains useful information, especially when studying molecular dynamics. This contribution represents a review of the concept of applying the Breit-Rabi formalism to coupled nuclear spins and discusses the immobilization of different metabolites in anisotropic tissue revealed by 1H NMR spectra of carnosine, phosphocreatine and taurine. Comparison of atomic and molecular spin systems allows for statements on the biological constraints for direct spin-spin interactions. Moreover, the relevance of hyperfine effects on the line shapes of multiplets of indirectly-coupled spin systems with more than two constituents can be predicted by analyzing quantum mechanical parameters. As an example, the superposition of eigenstates of the AMX system of adenosine 5'-triphosphate and its application for better quantification of 31P-NMR spectra will be discussed. (orig.)

  7. [Hyperfine structure analysis in magnetic resonance spectroscopy: from astrophysical measurements towards endogenous biosensors in human tissue].

    Science.gov (United States)

    Schröder, Leif

    2007-01-01

    The hyperfine interaction of two spins is a well studied effect in atomic systems. Magnetic resonance experiments demonstrate that the detectable dipole transitions are determined by the magnetic moments of the constituents and the external magnetic field. Transferring the corresponding quantum mechanics to molecular bound nuclear spins allows for precise prediction of NMR spectra obtained from metabolites in human tissue. This molecular hyperfine structure has been neglected so far in in vivo NMR spectroscopy but contains useful information, especially when studying molecular dynamics. This contribution represents a review of the concept of applying the Breit-Rabi formalism to coupled nuclear spins and discusses the immobilization of different metabolites in anisotropic tissue revealed by 1H NMR spectra of carnosine, phosphocreatine and taurine. Comparison of atomic and molecular spin systems allows for statements on the biological constraints for direct spin-spin interactions. Moreover, the relevance of hyperfine effects on the line shapes of multiplets of indirectly-coupled spin systems with more than two constituents can be predicted by analyzing quantum mechanical parameters. As an example, the superposition of eigenstates of the A MX system of adenosine 5'-triphosphate and its application for better quantification of 31P-NMR spectra will be discussed.

  8. Cardiovascular fluid dynamics. Methods for flow and pressure field analysis from magnetic resonance imaging

    International Nuclear Information System (INIS)

    Ebbers, T.

    2001-01-01

    Cardiovascular blood flow is highly complex and incompletely understood. Blood flow patterns are expected to influence the opening and closing of normal and prosthetic heart valves, the efficiency of cardiac filling and ejection, and the resistance to thrombus formation within the heart. Conventional diagnostic techniques are poorly suited to the study of the three-dimensional (3D) blood flow patterns in the heart chambers and large vessels. Noninvasive methods have also been inadequate in studying intracardiac pressure differences, which are the driving force of flow and are critical in the evaluation of many cardiovascular abnormalities. This thesis focuses on the development of non-invasive methods for analysis of 3D cardiovascular blood flow. Simultaneous study of cardiovascular fluid dynamics allowed knowledge exchange across the two disciplines, facilitating the development process and broadening the applicability of the methods. A time-resolved 3D phase-contrast Magnetic Resonance Imaging (MRI) technique was used to acquire the velocity vector field in a 3D volume encompassing the entire heart or a large vessel. Cardiovascular blood flow patterns were visualized by use of particle traces, which revealed, for instance, vortical flow patterns in the left atrium. By applying the Navier-Stokes equation along a user-defined line in the 3D velocity vector field, the relative pressure could be obtained as an excellent supplement to the flow pattern visualization. Using a delineation of the blood pool, the time-varying 3D relative pressure field in the human left ventricle was obtained from the velocity field by use of the pressure Poisson equation. A delineation of the heart muscle, a task that is almost impossible to perform on 3D MRI either automatically or manually, was also achieved by usage of particle traces. This segmentation allows automatic calculation of the 3D relative pressure field, as well as calculation of well-established parameters such as

  9. H Nuclear magnetic resonance based metabonomics data analysis in rheumatoid arthritis

    Directory of Open Access Journals (Sweden)

    Mohammad Arjmand

    2014-05-01

    Full Text Available Background: Rheumatoid arthritis (RA is a chronic, systematic inflammatory disorder that may affect many tissues and organs, but principally attacks synovial joints and it is a common rheumatic disease with many subtypes. Nuclear Magnetic resonance (1H NMR spectrometers with high sensitivity, resolution and dynamic range has permitted the rapid, simultaneous investigation of complex mixtures of endogenous or exogenous components present in biological materials. Metabonomics is the systematic study of chemical finger print resulted from cell reactions and could be used as a new biomarker for early disease diagnosis. In the present investigation, we studied serum metabolic profile in rheumatoid arthritis (RA in order to find out the metabolic finger print pattern of the disease. Materials and methods: In our metabonomics study serum samples were collected from 16 patients with active RA, and from equal number of healthy subjects. They were evaluated during a one-year follow-up with the assessment of disease activity and 1H NMR spectroscopy of sera samples. In all the cases, the presence of active rheumatoid arthritis was shown by an increase in the T1 values of the synovium of the joints. We specified and classified all metabolites using PCA, PLSDA chemometrics methods. Chenomx (Trail Version and ProMetab codes in Matlab software environments were used for our data analysis. Results were compared with the NMR metabolite data bank (www.metabolomics.ca. Anti-CCP, ANA and urea were also analyzed by ElISA and colorimetric methods respectively. Results: The most changes identified in this study were in the biosynthesis pathways of steroid hormones, biotin, fatty acids, amino acids (Leucine, Valin and isoleucine and also linoleic acid. Conclusion: In rheumatoid arthritis disease, the activation of the immune system consumes larg amounts of energy. The main donor of free energy in cells is ATP, which is generated by both glycolysis and oxidative

  10. Cardiovascular fluid dynamics. Methods for flow and pressure field analysis from magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ebbers, T

    2001-05-01

    Cardiovascular blood flow is highly complex and incompletely understood. Blood flow patterns are expected to influence the opening and closing of normal and prosthetic heart valves, the efficiency of cardiac filling and ejection, and the resistance to thrombus formation within the heart. Conventional diagnostic techniques are poorly suited to the study of the three-dimensional (3D) blood flow patterns in the heart chambers and large vessels. Noninvasive methods have also been inadequate in studying intracardiac pressure differences, which are the driving force of flow and are critical in the evaluation of many cardiovascular abnormalities. This thesis focuses on the development of non-invasive methods for analysis of 3D cardiovascular blood flow. Simultaneous study of cardiovascular fluid dynamics allowed knowledge exchange across the two disciplines, facilitating the development process and broadening the applicability of the methods. A time-resolved 3D phase-contrast Magnetic Resonance Imaging (MRI) technique was used to acquire the velocity vector field in a 3D volume encompassing the entire heart or a large vessel. Cardiovascular blood flow patterns were visualized by use of particle traces, which revealed, for instance, vortical flow patterns in the left atrium. By applying the Navier-Stokes equation along a user-defined line in the 3D velocity vector field, the relative pressure could be obtained as an excellent supplement to the flow pattern visualization. Using a delineation of the blood pool, the time-varying 3D relative pressure field in the human left ventricle was obtained from the velocity field by use of the pressure Poisson equation. A delineation of the heart muscle, a task that is almost impossible to perform on 3D MRI either automatically or manually, was also achieved by usage of particle traces. This segmentation allows automatic calculation of the 3D relative pressure field, as well as calculation of well-established parameters such as

  11. 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...

  12. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

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

  13. 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 About Us News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - ...

  14. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... Magnetic Resonance Imaging Sponsored by Please note RadiologyInfo.org is not a medical facility. Please contact your ... links: For the convenience of our users, RadiologyInfo .org provides links to relevant websites. RadiologyInfo.org , ACR ...

  15. 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 About Us News Physician ... Magnetic resonance imaging (MRI) is a noninvasive medical test that physicians use to diagnose medical conditions. MRI ...

  16. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician ... Magnetic resonance imaging (MRI) is a noninvasive medical test that physicians use to diagnose medical conditions. MRI ...

  17. 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 ...

  18. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... of which shows a thin slice of the body. The images can then be studied from different angles by ... about radiology? Share your patient story here Images ... Articles and Media Catheter Angiography Magnetic Resonance, Functional (fMRI) - Brain Children's ( ...

  19. Investigation on Mechanisms of Polymer Enhanced Oil Recovery by Nuclear Magnetic Resonance and Microscopic Theoretical Analysis

    International Nuclear Information System (INIS)

    Ji-Cheng, Zhang; Kao-Ping, Song; Er-Long, Yang; Li, Liu

    2008-01-01

    Polymer flooding is an efficient technique to enhance oil recovery over water flooding. There are lots of discussions regarding the mechanisms for polymer flooding enhancing oil recovery. The main focus is whether polymer flooding can increase sweep efficiency alone, or can increase both of sweep efficiency and displacement efficiency. We present a study on this problem. Oil displacement experiments on 4 natural cores show that polymer flooding can increase oil recovery efficiency by more than 12% over water. Moreover, photos are taken by the nuclear magnetic resonance (NMR) method both after water flooding and after polymer flooding, which show remaining oil saturation distribution at the middle cross section and the central longitudinal section. Analyses of these photos demonstrate that polymer flooding can increase both sweep efficiency and displacement efficiency. (fundamental areas of phenomenology (including applications))

  20. Diabetic neuropathy: structural analysis of nerve hydration by Magnetic Resonance Spectroscopy

    International Nuclear Information System (INIS)

    Griffey, R.H.; Eaton, P.; Sibbitt, R.R.; Sibbitt, W.L. Jr.; Bicknell, J.M.

    1988-01-01

    The water content of the sural nerve of diabetic patients was quantitatively defined by magnetic resonance proton imaging as a putative reflection of activity of the aldose-reductase pathway. Thirty-nine patients were evaluated, comparing group A, symptomatic diabetic men with sensory neuropathy; group B, similarly symptomatic diabetic men treated aldose-reductase inhibition; group C, neurologically asymptomatic diabetic men; and group D, control nondiabetic men. Marked increase in hydration of the sural nerve was seen in more than half of the symptomatic diabetic patients. Two of 11 neurologically asymptomatic diabetics had increased nerve hydration, suggesting a presymptomatic alteration of the nerve. Symptomatic diabetics treated with aldose-reductase inhibitors had normal nerve water levels. Increased level of peripheral nerve water represents a new finding in diabetes mellitus. It seems to be related to aldose-reductase activity, involved in the development of neuropathy, and similar to events that occur in other target tissue in human diabetes

  1. Discriminating poststroke depression from stroke by nuclear magnetic resonance spectroscopy-based metabonomic analysis

    Directory of Open Access Journals (Sweden)

    Xiao J

    2016-08-01

    Full Text Available Jianqi Xiao,1,* Jie Zhang,2,* Dan Sun,3,* Lin Wang,4,* Lijun Yu,5 Hongjing Wu,5 Dan Wang,5 Xuerong Qiu5 1Department of Neurosurgery, The First Hospital of Qiqihar City, Qiqihar, 2Department of Internal Medicine, Central Hospital of Jiamusi City, Jiamusi, 3Department of Geriatrics, General Hospital of Daqing Oil Field, Daqing, 4Department of Nursing, 5Department of Neurology, The First Hospital of Qiqihar City, Qiqihar, Heilongjiang, People’s Republic of China *These authors contributed equally to this work Abstract: Poststroke depression (PSD, the most common psychiatric disease that stroke survivors face, is estimated to affect ~30% of poststroke patients. However, there are still no objective methods to diagnose PSD. In this study, to explore the differential metabolites in the urine of PSD subjects and to identify a potential biomarker panel for PSD diagnosis, the nuclear magnetic resonance-based metabonomic method was applied. Ten differential metabolites responsible for discriminating PSD subjects from healthy control (HC and stroke subjects were found, and five of these metabolites were identified as potential biomarkers (lactate, α-hydroxybutyrate, phenylalanine, formate, and arabinitol. The panel consisting of these five metabolites provided excellent performance in discriminating PSD subjects from HC and stroke subjects, achieving an area under the receiver operating characteristic curve of 0.946 in the training set (43 HC, 45 stroke, and 62 PSD subjects. Moreover, this panel could classify the blinded samples from the test set (31 HC, 33 stroke, and 32 PSD subjects with an area under the curve of 0.946. These results laid a foundation for the future development of urine-based objective methods for PSD diagnosis and investigation of PSD pathogenesis. Keywords: poststroke depression, PSD, stroke, nuclear magnetic resonance, NMR, metabonomic

  2. Magnetic Resonance Imaging (MRI): Brain (For Parents)

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Magnetic Resonance Imaging (MRI): Brain KidsHealth / For Parents / Magnetic Resonance Imaging (MRI): Brain What's in this article? What ...

  3. 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.

  4. Numerical methods in electron magnetic resonance

    International Nuclear Information System (INIS)

    Soernes, A.R.

    1998-01-01

    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

  5. 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.

  6. Proceedings of the nuclear magnetic resonance user meeting

    International Nuclear Information System (INIS)

    1987-01-01

    Studies on utilization of nuclear magnetic resonance, such as: chemical analysis in complexes and organic compounds; structures and magnetic properties of solids; construction of images and; spectrometer designs, are presented. (M.C.K.) [pt

  7. Magnetic resonance for wireless power transfer

    OpenAIRE

    Hui, SYR

    2016-01-01

    Magnetic resonance has been a cornerstone of nonradiative wireless power transfer (WPT) since the late 19th century. However, some researchers have the misconception that magnetic resonance for WPT was developed recently. This article traces some early work of Tesla and other researchers related to the use of magnetic resonance in WPT. Included are some examples of magnetic resonance-based WPT projects conducted by researchers in the biomedical and power electronics communities over the last ...

  8. Magnetic resonance tomography in syringomyelia

    International Nuclear Information System (INIS)

    Koehler, D.; Treisch, J.; Hertel, G.; Schoerner, W.; Fiegler, W.; Staedtisches Rudolf-Virchow Krankenhaus, Berlin

    1985-01-01

    Thirteen patients with a clinical diagnosis of syringomyelia were examined by nuclear tomography (0.35 T magnet) in the spin-echo mode. In all thirteen patients, the T1 images (Se 400/35) showed a longitudinal cavity with a signal intensity of CSF. The shape and extent of the syrinx could be adequately demonstrated in 12 of the 13 examinations. Downward displacement of the cerebellar tonsils was seen in eight cases. The examination took between half and one hour. Advantages of magnetic resonance tomography (nuclear tomography) include the absence of artifacts, images in the line of the lesion and its non-invasiveness. (orig.) [de

  9. Limits to magnetic resonance microscopy

    International Nuclear Information System (INIS)

    Glover, Paul; Mansfield, Peter

    2002-01-01

    The last quarter of the twentieth century saw the development of magnetic resonance imaging (MRI) grow from a laboratory demonstration to a multi-billion dollar worldwide industry. There is a clinical body scanner in almost every hospital of the developed nations. The field of magnetic resonance microscopy (MRM), after mostly being abandoned by researchers in the first decade of MRI, has become an established branch of the science. This paper reviews the development of MRM over the last decade with an emphasis on the current state of the art. The fundamental principles of imaging and signal detection are examined to determine the physical principles which limit the available resolution. The limits are discussed with reference to liquid, solid and gas phase microscopy. In each area, the novel approaches employed by researchers to push back the limits of resolution are discussed. Although the limits to resolution are well known, the developments and applications of MRM have not reached their limit. (author)

  10. Nuclear magnetic resonance spectrometry

    International Nuclear Information System (INIS)

    Wasson, J.R.; Salinas, J.E.

    1980-01-01

    Of the thousands of publications available for the period from July 1977 to July 1979, only a few were selected for this review. Approximately 130 review sources are summarized in tabular form as to topic(s) covered in the review. Other parts of the review article deal with apparatus and techniques, spectral analysis, computer applications, analytical applications, selected organic systems, and selected inorganic systems. A total of 257 references are cited

  11. Magnetic resonance and its applications

    CERN Document Server

    Chizhik, Vladimir I; Donets, Alexey V; Frolov, Vyacheslav V; Komolkin, Andrei V; Shelyapina, Marina G

    2014-01-01

    The book provides a basic understanding of the underlying theory, fundamentals and applications of magnetic resonance The book implies a few levels of the consideration (from simple to complex) of phenomena, that can be useful for different groups of readers The introductory chapter provides the necessary underpinning knowledge for newcomers to the methods The exposition of theoretical materials goes from initial to final formulas through detailed intermediate expressions.

  12. 31P-nuclear magnetic resonance analysis of extracts of vascular smooth muscle

    International Nuclear Information System (INIS)

    Barron, J.T.; Messer, J.V.; Glonek, Thomas

    1986-01-01

    31 P-nuclear magnetic resonance spectroscopy was used to assess phosphate metabolites in perchloric acid extracts of rabbit aorta. In addition to the high energy phosphates, several other phosphorus compounds were detected and quantified. Most notable was the presence of a prominent phosphomonoester compound appearing at a chemical shift of 3.86 delta. This compound constituted 26% of the total extractable tissue phosphorus and is tentatively identified as ribose-5-phosphate, a pentose phosphate pathway intermediate. While ATP and phosphocreatine did not change during glucose and oxygen deprivation or during prolonged muscle contraction, the 3.86delta phosphate decreased significantly. Furthermore, theophylline, an agent that increases intracellular cAMP, also decreased the level of the 3.86 delta phosphate. These results are consistent with the concept that intermediate metabolism sustains high energy phosphate pools in vascular smooth muscle in the steady state under various conditions. The pentose phosphate pathway may play an important role in vascular smooth muscle metabolism. (author)

  13. Magnetic resonance imaging and quantitative analysis of contents of epidermoid and dermoid cysts

    Energy Technology Data Exchange (ETDEWEB)

    Takeshita, Mikihiko; Kubo, Osami; Hiyama, Hirofumi; Tajika, Yasuhiko; Izawa, Masahiro; Kagawa, Mizuo; Takakura, Kintomo; Kobayashi, Naotoshi; Toyoda, Masako [Tokyo Women' s Medical Coll. (Japan)

    1994-07-01

    The intracapsular cholesterol protein, and calcium contents of epidermoid and dermoid cysts from seven patients were compared with the signal intensities on T[sub 1]-weighted spin-echo magnetic resonance (MR) images. All specimens had a paste-like consistency when resected. Epidermoid and dermoid cysts demonstrated a wide range of cholesterol and calcium contents, and epidermoid cysts were not always rich in cholesterol. Five patients had cysts with lower signal intensity than white matter, which contained more than 18.3 mg/g wet weight of protein. One of these patients had the highest cholesterol content of all seven patients (22.25 mg/g wet weight) and another had the highest calcium content (0.75 mg/g wet weight). Two patients had cysts with higher signal intensity than white matter, with protein contents of lower than 4.3 mg/g wet weight. High protein content (>18.3 mg/g wet weight) may decrease signal intensity on T[sub 1]-weighted MR images, while low protein content (<4.3 mg/g wet weight) may increase signal intensity in epidermoid and dermoid cysts with high viscosity (paste-like consistency) contents. (author).

  14. Venous reflux on contrast-enhanced head and neck magnetic resonance angiography: Analysis of causative factors

    International Nuclear Information System (INIS)

    Shin, Dong Jae; Lee, Eun Ja; Bae, Jong Myon

    2016-01-01

    The purpose of this study was to analyze the causative factors of venous reflux on contrast-enhanced head and neck magnetic resonance angiography. We retrospectively reviewed 150 patients with right-arm injections and 150 patients with left-arm injections. We included the age, gender, body mass index, history of hypertension, and history of diabetes mellitus in the evaluation of all patients. We measured the shortest width of the left or right brachiocephalic vein (BCV), the diameter of the aortic arch, and the distance between the sternum and vertebral body. The relationship between these factors and the venous reflux was analyzed. In patients with venous reflux, we performed qualitative image scoring for suboptimal images. In patients with venous reflux, the image quality of the left-arm injection group was significantly inferior to the image quality of the right-arm injection group. The mean age and the male-to-female ratio of patients with venous reflux were significantly higher than those of patients without venous reflux. In patients receiving the left-arm injection, the mean shortest width of the left BCV was significantly narrower in patients with venous reflux than in patients without venous reflux. A left-arm injection should be avoided, especially in elderly patients, to acquire an optimal image

  15. Venous reflux on contrast-enhanced head and neck magnetic resonance angiography: Analysis of causative factors

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Dong Jae; Lee, Eun Ja [Dept. of Radiology, Dongguk University Ilsan Hospital, Goyang (Korea, Republic of); Bae, Jong Myon [Dept. of Preventive Medicine, Jeju National University School of Medicine, Jeju (Korea, Republic of)

    2016-12-15

    The purpose of this study was to analyze the causative factors of venous reflux on contrast-enhanced head and neck magnetic resonance angiography. We retrospectively reviewed 150 patients with right-arm injections and 150 patients with left-arm injections. We included the age, gender, body mass index, history of hypertension, and history of diabetes mellitus in the evaluation of all patients. We measured the shortest width of the left or right brachiocephalic vein (BCV), the diameter of the aortic arch, and the distance between the sternum and vertebral body. The relationship between these factors and the venous reflux was analyzed. In patients with venous reflux, we performed qualitative image scoring for suboptimal images. In patients with venous reflux, the image quality of the left-arm injection group was significantly inferior to the image quality of the right-arm injection group. The mean age and the male-to-female ratio of patients with venous reflux were significantly higher than those of patients without venous reflux. In patients receiving the left-arm injection, the mean shortest width of the left BCV was significantly narrower in patients with venous reflux than in patients without venous reflux. A left-arm injection should be avoided, especially in elderly patients, to acquire an optimal image.

  16. Nuclear magnetic resonance spectroscopic and isotopic analysis of carbonized residues from subarctic Canadian prehistoric pottery

    International Nuclear Information System (INIS)

    Sherriff, B.L.; Tisdale, M.A.; Sayer, B.G.; Schwarcz, H.P.; Knyf, M.

    1995-01-01

    Late prehistoric pottery is found in abundance at archaeological sites around Southern Indian Lake. Black residues, found on the two dominant vessel forms, flat plates and round pots, are presumed to be the remains of prehistoric meals. 13 C cross-polarization magic-angle-spinning nuclear magnetic resonance spectroscopy (CPMAS NMR) and 13 C and 15 N isotopic ratios and C/N ratios are used to reconstruct prehistoric diet and to shed light on possible uses for the plates. Samples of foods were cooked in clay pots, on a wood fire, to simulate the conditions of burning that could have produced the residue. Decomposition of carbohydrates, protein, and fat during cooking is studied with 13 C CPMAS NMR, and the effect of cooking on isotopic and C/N ratios documented. Predominantly fish and fat were cooked in the pots, whereas the residues from plates contain a greater proportion of fat and could have been used as frying pans or possibly as fat-burning lamps placed on the ashes of a wood fire. (Author)

  17. Multiparametric analysis of magnetic resonance images for glioma grading and patient survival time prediction

    International Nuclear Information System (INIS)

    Garzon, Benjamin; Emblem, Kyrre E.; Mouridsen, Kim; Nedregaard, Baard; Due-Toennessen, Paulina; Nome, Terje; Hald, John K.; Bjoernerud, Atle; Haaberg, Asta K.; Kvinnsland, Yngve

    2011-01-01

    Background. A systematic comparison of magnetic resonance imaging (MRI) options for glioma diagnosis is lacking. Purpose. To investigate multiple MR-derived image features with respect to diagnostic accuracy in tumor grading and survival prediction in glioma patients. Material and Methods. T1 pre- and post-contrast, T2 and dynamic susceptibility contrast scans of 74 glioma patients with histologically confirmed grade were acquired. For each patient, a set of statistical features was obtained from the parametric maps derived from the original images, in a region-of-interest encompassing the tumor volume. A forward stepwise selection procedure was used to find the best combinations of features for grade prediction with a cross-validated logistic model and survival time prediction with a cox proportional-hazards regression. Results. Presence/absence of enhancement paired with kurtosis of the FM (first moment of the first-pass curve) was the feature combination that best predicted tumor grade (grade II vs. grade III-IV; median AUC 0.96), with the main contribution being due to the first of the features. A lower predictive value (median AUC = 0.82) was obtained when grade IV tumors were excluded. Presence/absence of enhancement alone was the best predictor for survival time, and the regression was significant (P < 0.0001). Conclusion. Presence/absence of enhancement, reflecting transendothelial leakage, was the feature with highest predictive value for grade and survival time in glioma patients

  18. Analysis of systemic lupus erythematosus (SLE) involving the central nervous system by magnetic resonance imaging (MRI)

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Kimihiro; Hara, Masako; Nakajima, Shinji and others

    1989-04-01

    Involvement of the central nervous system (CNS) commonly occurs in systemic lupus erythematosus (SLE). But definitive diagnosis remains difficult even with computed tomography (CT). In this study, we used the recently developed technique, magnetic resonance imaging (MRI) for CNS lupus and compared it with CT scans. CT was performed with a General Electric 8800 CT/T scanner. MRI was performed using a Mitsubishi Electric MMI-150 S. Ten patients with CNS lupus were divided into 3 groups. Group I included 4 cases with neurological manifestations alone. All lesions seen on CT were also detected by MRI, with greater clarity and extent. Furthermore, MRI depicted several microinfarcts in white matter without symptoms. Group II included 5 cases with psychiatric features alone. MRI detected a thalamic microinfarct in only one case while CT showed no abnormality in all cases. Group III included 1 case with both neurological and psychiatric symptoms. MRI demonstrated a small infarct of midbrain corresponding with neurological symptoms, more clearly than CT. Therefore MRI demonstrates the degree of brain involvement in SLE more accurately than CT. (author).

  19. Analysis of systemic lupus erythematosus (SLE) involving the central nervous system by magnetic resonance imaging (MRI)

    International Nuclear Information System (INIS)

    Suzuki, Kimihiro; Hara, Masako; Nakajima, Shinji

    1989-01-01

    Involvement of the central nervous system (CNS) commonly occurs in systemic lupus erythematosus (SLE). But definitive diagnosis remains difficult even with computed tomography (CT). In this study, we used the recently developed technique, magnetic resonance imaging (MRI) for CNS lupus and compared it with CT scans. CT was performed with a General Electric 8800 CT/T scanner. MRI was performed using a Mitsubishi Electric MMI-150 S. Ten patients with CNS lupus were divided into 3 groups. Group I included 4 cases with neurological manifestations alone. All lesions seen on CT were also detected by MRI, with greater clarity and extent. Furthermore, MRI depicted several microinfarcts in white matter without symptoms. Group II included 5 cases with psychiatric features alone. MRI detected a thalamic microinfarct in only one case while CT showed no abnormality in all cases. Group III included 1 case with both neurological and psychiatric symptoms. MRI demonstrated a small infarct of midbrain corresponding with neurological symptoms, more clearly than CT. Therefore MRI demonstrates the degree of brain involvement in SLE more accurately than CT. (author)

  20. H-1 Nuclear Magnetic Resonance Metabolomics Analysis Identifies Novel Urinary Biomarkers for Lung Function

    International Nuclear Information System (INIS)

    McClay, Joseph L.; Adkins, Daniel E.; Isern, Nancy G.; O'Connell, Thomas M.; Wooten, Jan B.; Zedler, Barbara K.; Dasika, Madhukar S.; Webb, B.T.; Webb-Robertson, Bobbie-Jo M.; Pounds, Joel G.; Murrelle, Edward L.; Leppert, Mark F.; van den Oord, Edwin J.

    2010-01-01

    Chronic obstructive pulmonary disease (COPD), characterized by chronic airflow limitation, is a serious and growing public health concern. The major environmental risk factor for COPD is tobacco smoking, but the biological mechanisms underlying COPD are not well understood. In this study, we used proton nuclear magnetic resonance (1H-NMR) spectroscopy to identify and quantify metabolites associated with lung function in COPD. Plasma and urine were collected from 197 adults with COPD and from 195 adults without COPD. Samples were assayed using a 600 MHz NMR spectrometer, and the resulting spectra were analyzed against quantitative spirometric measures of lung function. After correcting for false discoveries and adjusting for covariates (sex, age, smoking) several spectral regions in urine were found to be significantly associated with baseline lung function. These regions correspond to the metabolites trigonelline, hippurate and formate. Concentrations of each metabolite, standardized to urinary creatinine, were associated with baseline lung function (minimum p-value = 0.0002 for trigonelline). No significant associations were found with plasma metabolites. Two of the three urinary metabolites positively associated with baseline lung function, i.e. hippurate and formate, are often related to gut microflora. This suggests that the microbiome composition is variable between individuals with different lung function. Alternatively, the nature and origins of all three associated metabolites may reflect lifestyle differences affecting overall health. Our results will require replication and validation, but demonstrate the utility of NMR metabolomics as a screening tool for identifying novel biomarkers of lung disease or disease risk.

  1. Multiparametric analysis of magnetic resonance images for glioma grading and patient survival time prediction

    Energy Technology Data Exchange (ETDEWEB)

    Garzon, Benjamin (Dept. of Circulation and Medical Imaging, NTNU, Trondheim (Norway)), email: benjamin.garzon@ntnu.no; Emblem, Kyrre E. (The Interventional Center, Rikshospitalet, Oslo Univ. Hospital, Oslo (Norway); Dept. of Radiology, MGH-HST AA Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston (United States)); Mouridsen, Kim (Center of Functionally Integrative Neuroscience, Aarhus Univ., Aarhus (Denmark)); Nedregaard, Baard; Due-Toennessen, Paulina; Nome, Terje; Hald, John K. (Dept. of Radiology and Nuclear Medicine, Rikshospitalet, Oslo Univ. Hospital, Oslo (Norway)); Bjoernerud, Atle (The Interventional Center, Rikshospitalet, Oslo Univ. Hospital, Oslo (Norway)); Haaberg, Asta K. (Dept. of Circulation and Medical Imaging, NTNU, Trondheim (Norway); Dept. of Medical Imaging, St Olav' s Hospital, Trondheim (Norway)); Kvinnsland, Yngve (NordicImagingLab, Bergen (Norway))

    2011-11-15

    Background. A systematic comparison of magnetic resonance imaging (MRI) options for glioma diagnosis is lacking. Purpose. To investigate multiple MR-derived image features with respect to diagnostic accuracy in tumor grading and survival prediction in glioma patients. Material and Methods. T1 pre- and post-contrast, T2 and dynamic susceptibility contrast scans of 74 glioma patients with histologically confirmed grade were acquired. For each patient, a set of statistical features was obtained from the parametric maps derived from the original images, in a region-of-interest encompassing the tumor volume. A forward stepwise selection procedure was used to find the best combinations of features for grade prediction with a cross-validated logistic model and survival time prediction with a cox proportional-hazards regression. Results. Presence/absence of enhancement paired with kurtosis of the FM (first moment of the first-pass curve) was the feature combination that best predicted tumor grade (grade II vs. grade III-IV; median AUC 0.96), with the main contribution being due to the first of the features. A lower predictive value (median AUC = 0.82) was obtained when grade IV tumors were excluded. Presence/absence of enhancement alone was the best predictor for survival time, and the regression was significant (P < 0.0001). Conclusion. Presence/absence of enhancement, reflecting transendothelial leakage, was the feature with highest predictive value for grade and survival time in glioma patients

  2. Myocardial tagging by Cardiovascular Magnetic Resonance: evolution of techniques--pulse sequences, analysis algorithms, and applications

    Directory of Open Access Journals (Sweden)

    Ibrahim El-Sayed H

    2011-07-01

    Full Text Available Abstract Cardiovascular magnetic resonance (CMR tagging has been established as an essential technique for measuring regional myocardial function. It allows quantification of local intramyocardial motion measures, e.g. strain and strain rate. The invention of CMR tagging came in the late eighties, where the technique allowed for the first time for visualizing transmural myocardial movement without having to implant physical markers. This new idea opened the door for a series of developments and improvements that continue up to the present time. Different tagging techniques are currently available that are more extensive, improved, and sophisticated than they were twenty years ago. Each of these techniques has different versions for improved resolution, signal-to-noise ratio (SNR, scan time, anatomical coverage, three-dimensional capability, and image quality. The tagging techniques covered in this article can be broadly divided into two main categories: 1 Basic techniques, which include magnetization saturation, spatial modulation of magnetization (SPAMM, delay alternating with nutations for tailored excitation (DANTE, and complementary SPAMM (CSPAMM; and 2 Advanced techniques, which include harmonic phase (HARP, displacement encoding with stimulated echoes (DENSE, and strain encoding (SENC. Although most of these techniques were developed by separate groups and evolved from different backgrounds, they are in fact closely related to each other, and they can be interpreted from more than one perspective. Some of these techniques even followed parallel paths of developments, as illustrated in the article. As each technique has its own advantages, some efforts have been made to combine different techniques together for improved image quality or composite information acquisition. In this review, different developments in pulse sequences and related image processing techniques are described along with the necessities that led to their invention

  3. Hepatic fat quantification: a prospective comparison of magnetic resonance spectroscopy and analysis methods for chemical-shift gradient echo magnetic resonance imaging with histologic assessment as the reference standard.

    Science.gov (United States)

    Kang, Bo-Kyeong; Yu, Eun Sil; Lee, Seung Soo; Lee, Youngjoo; Kim, Namkug; Sirlin, Claude B; Cho, Eun Yoon; Yeom, Suk Keu; Byun, Jae Ho; Park, Seong Ho; Lee, Moon-Gyu

    2012-06-01

    The aims of this study were to assess the confounding effects of hepatic iron deposition, inflammation, and fibrosis on hepatic steatosis (HS) evaluation by magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) and to assess the accuracies of MRI and MRS for HS evaluation, using histology as the reference standard. In this institutional review board-approved prospective study, 56 patients gave informed consents and underwent chemical-shift MRI and MRS of the liver on a 1.5-T magnetic resonance scanner. To estimate MRI fat fraction (FF), 4 analysis methods were used (dual-echo, triple-echo, multiecho, and multi-interference), and MRS FF was calculated with T2 correction. Degrees of HS, iron deposition, inflammation, and fibrosis were analyzed in liver resection (n = 37) and biopsy (n = 19) specimens. The confounding effects of histology on fat quantification were assessed by multiple linear regression analysis. Using the histologic degree of HS as the reference standard, the accuracies of each method in estimating HS and diagnosing an HS of 5% or greater were determined by linear regression and receiver operating characteristic analyses. Iron deposition significantly confounded estimations of FF by the dual-echo (P hepatic fat, with coexisting histologic abnormalities having no confounding effects.

  4. Magnetic resonance study of maghemite-based magnetic fluid

    International Nuclear Information System (INIS)

    Figueiredo, L.C.; Lacava, B.M.; Skeff Neto, K.; Pelegrini, F.; Morais, P.C.

    2008-01-01

    This study reports on the magnetic resonance (MR) data (X-band experiment) of 10.2 nm average diameter maghemite nanoparticle in the temperature range of 100-230 K. Maghemite nanoparticles were suspended as low-pH ionic magnetic fluid containing 2.3x10 17 particles/cm 3 . The temperature dependence of both resonance linewidth and resonance field of the zero-field-cooled sample as well as the resonance field of the field-cooled sample (angular variation experiment) was analyzed using well-established methodology. Information regarding particle size, particle clusterization and surface magnetic anisotropy were obtained from the analysis of the MR data. The number of magnetic sites per particle from the MR data is in excellent agreement with the number provided by the transmission electron microscopy (TEM) data. The demagnetizing field value obtained from the MR data indicates cluster of particles containing on average 1.42 particles. The MR angular variation data suggest that magnetoelastic effect accounts for the non-linearity observed for the surface component of the magnetic anisotropy

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

    International Nuclear Information System (INIS)

    Quibilan, E.I.

    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)

  6. 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)

  7. Magnetic resonance imaging in sudden deafness

    International Nuclear Information System (INIS)

    Ramos, Hugo Valter Lisboa; Barros, Flavia Alencar; Penido, Norma de Oliveira; Souza, Ana Claudia Valerio de; Yamaoka, Wellington Yugo; Yamashita, Helio

    2005-01-01

    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)

  8. Nuclear magnetic resonance spectroscopy in organic chemistry. 2. ed.

    International Nuclear Information System (INIS)

    Zschunke, A.

    1977-01-01

    The fundamentals of nuclear magnetic resonance spectroscopy are discussed only briefly. The emphasis is laid on developing reader's ability to evaluate resonance spectra. The following topics are covered: principles of nuclear magnetic resonance spectroscopy; chemical shift and indirect nuclear spin coupling constants and their relation to the molecular structure; analysis of spectra; and uses for structural analysis and solution of kinetic problems, mainly with regard to organic compounds. Of interest to chemists and graduate students who want to make themselves acquainted with nuclear magnetic resonance spectroscopy

  9. Skeletal muscle metastases on magnetic resonance imaging: analysis of 31 cases

    Directory of Open Access Journals (Sweden)

    Qi Li

    2016-08-01

    Full Text Available Aim of the study : To investigate the magnetic resonance imaging (MRI features of skeletal muscle metastases (SMM. Material and methods: The records of 31 patients with proven SMM were retrospectively reviewed. Clinical history, type of primary malignancy, location of metastases, and MRI features of SMM were evaluated. Based on MRI findings, SMM were divided into three MRI types. The correlation between MRI types with ages and pathology category, between MRI types of SMM and ages, as well as MRI types of SMM and pathology category were analysed with Spearman’s rho. Results: The most common primary tumour was genital tumour (25.8% and bronchial carcinoma (19.4%, and the most common cell type was adenocarcinoma (58.1%. SMM were located in the iliopsoas muscle (26.3%, paravertebral muscles (21.1%, and upper extremity muscles (18.4%. MRI features: (1 Type-I localised lesions (12.90%, round-like mass limited to local regions with heterogeneous iso-signal intensity in T1WI and heterogeneous hyper-intensity in T2WI; (2 Type-II diffuse lesions without bone destruction (35.48%, abnormal diffuse swelling of the muscle with irregular boundaries and slightly hypo- to iso-intensity in T1WI and hyper-intensity in T2WI; and (3 Type-III diffuse lesions with bone destruction (51.61%, distinct irregular lump with iso-intensity in T1WI and heterogeneous hyper-intensity in T2WI with adjacent bone invasion. There was positive correlation between MRI types and ages (r = 0.431, p 0.05. Conclusions : SMM features on MRI can be broadly used to classify lesions, which is beneficial for SMM diagnosis.

  10. Analysis of GAA/TTC DNA triplexes using nuclear magnetic resonance and electrospray ionization mass spectrometry.

    Science.gov (United States)

    Mariappan, S V Santhana; Cheng, Xun; van Breemen, Richard B; Silks, Louis A; Gupta, Goutam

    2004-11-15

    The formation of a GAA/TTC DNA triplex has been implicated in Friedreich's ataxia. The destabilization of GAA/TTC DNA triplexes either by pH or by binding to appropriate ligands was analyzed by nuclear magnetic resonance (NMR) and positive-ion electrospray mass spectrometry. The triplexes and duplexes were identified by changes in the NMR chemical shifts of H8, H1, H4, 15N7, and 15N4. The lowest pH at which the duplex is detectable depends upon the overall stability and the relative number of Hoogsteen C composite function G to T composite function A basepairs. A melting pH (pHm) of 7.6 was observed for the destabilization of the (GAA)2T4(TTC)2T4(CTT)2 triplex to the corresponding Watson-Crick duplex and the T4(CTT)2 overhang. The mass spectrometric analyses of (TTC)6.(GAA)6 composite function(TTC)6 triplex detected ions due to both triplex and single-stranded oligonucleotides under acidic conditions. The triplex ions disappeared completely at alkaline pH. Duplex and single strands were detectable only at neutral and alkaline pH values. Mass spectrometric analyses also showed that minor groove-binding ligands berenil, netropsin, and distamycin and the intercalating ligand acridine orange destabilize the (TTC)6.(GAA)6 composite function (TTC)6 triplex. These NMR and mass spectrometric methods may function as screening assays for the discovery of agents that destabilize GAA/TTC triplexes and as general methods for the characterization of structure, dynamics, and stability of DNA and DNA-ligand complexes.

  11. Performance analysis of algorithms for retrieval of magnetic resonance images for interactive teleradiology

    Science.gov (United States)

    Atkins, M. Stella; Hwang, Robert; Tang, Simon

    2001-05-01

    We have implemented a prototype system consisting of a Java- based image viewer and a web server extension component for transmitting Magnetic Resonance Images (MRI) to an image viewer, to test the performance of different image retrieval techniques. We used full-resolution images, and images compressed/decompressed using the Set Partitioning in Hierarchical Trees (SPIHT) image compression algorithm. We examined the SPIHT decompression algorithm using both non- progressive and progressive transmission, focusing on the running times of the algorithm, client memory usage and garbage collection. We also compared the Java implementation with a native C++ implementation of the non- progressive SPIHT decompression variant. Our performance measurements showed that for uncompressed image retrieval using a 10Mbps Ethernet, a film of 16 MR images can be retrieved and displayed almost within interactive times. The native C++ code implementation of the client-side decoder is twice as fast as the Java decoder. If the network bandwidth is low, the high communication time for retrieving uncompressed images may be reduced by use of SPIHT-compressed images, although the image quality is then degraded. To provide diagnostic quality images, we also investigated the retrieval of up to 3 images on a MR film at full-resolution, using progressive SPIHT decompression. The Java-based implementation of progressive decompression performed badly, mainly due to the memory requirements for maintaining the image states, and the high cost of execution of the Java garbage collector. Hence, in systems where the bandwidth is high, such as found in a hospital intranet, SPIHT image compression does not provide advantages for image retrieval performance.

  12. Multidimensional Analysis of Magnetic Resonance Imaging Predicts Early Impairment in Thoracic and Thoracolumbar Spinal Cord Injury

    Science.gov (United States)

    Mabray, Marc C.; Whetstone, William D.; Dhall, Sanjay S.; Phillips, David B.; Pan, Jonathan Z.; Manley, Geoffrey T.; Bresnahan, Jacqueline C.; Beattie, Michael S.; Haefeli, Jenny

    2016-01-01

    Abstract Literature examining magnetic resonance imaging (MRI) in acute spinal cord injury (SCI) has focused on cervical SCI. Reproducible systems have been developed for MRI-based grading; however, it is unclear how they apply to thoracic SCI. Our hypothesis is that MRI measures will group as coherent multivariate principal component (PC) ensembles, and that distinct PCs and individual variables will show discriminant validity for predicting early impairment in thoracic SCI. We undertook a retrospective cohort study of 25 patients with acute thoracic SCI who underwent MRI on admission and had American Spinal Injury Association Impairment Scale (AIS) assessment at hospital discharge. Imaging variables of axial grade, sagittal grade, length of injury, thoracolumbar injury classification system (TLICS), maximum canal compromise (MCC), and maximum spinal cord compression (MSCC) were collected. We performed an analytical workflow to detect multivariate PC patterns followed by explicit hypothesis testing to predict AIS at discharge. All imaging variables loaded positively on PC1 (64.3% of variance), which was highly related to AIS at discharge. MCC, MSCC, and TLICS also loaded positively on PC2 (22.7% of variance), while variables concerning cord signal abnormality loaded negatively on PC2. PC2 was highly related to the patient undergoing surgical decompression. Variables of signal abnormality were all negatively correlated with AIS at discharge with the highest level of correlation for axial grade as assessed with the Brain and Spinal Injury Center (BASIC) score. A multiple variable model identified BASIC as the only statistically significant predictor of AIS at discharge, signifying that BASIC best captured the variance in AIS within our study population. Our study provides evidence of convergent validity, construct validity, and clinical predictive validity for the sampled MRI measures of SCI when applied in acute thoracic and thoracolumbar SCI. PMID:26414451

  13. The analysis of the pathophysiology of syringomyelia by means of magnetic resonance imaging

    International Nuclear Information System (INIS)

    Abe, Toshiaki

    1992-01-01

    The pathophysiology of syringomyelia was examined with magnetic resonance imaging (MRI) in 70 patients. According to complications, syringomyelia was classified as being associated with (1) Chiari malformation, (2) both Chiari malformation and basal arachnoiditis, (3) basal arachnoiditis, (4) an obstruction of the foramen Magendie, and (5) spinal arachnoiditis. MRI features in Type 1 included: wedge-shaped herniated tonsils with the cisterna magna, pencil-shaped rostral end of the intraspinal syrinx, and obliterated caudal part of the fourth ventricle. These findings suggested that the herniated tonsils might result in the disturbance of cerebro-spinal fluid (CSF) circulation. In Type 2, the tip of the herniated tonsils was round; a triangular space was noted between the herniated tonsils and the upper spinal cord; the rostral end of the intraspinal syrinx was round; and the caudal part of the fourth ventricle was well visualized. These findings revealed that the brain stem and spinal cord were less pressed, suggesting that CSF circulatory disturbance resulted from basal arachnoiditis around the foramen magnum. In Type 3, the cisterna magna was narrowed by a thickened arachnoid membrane. In type 4, the intraspinal syrinx was directly connected with the fourth ventricle via the patent central canal associated with hydrocephalus. The position of the cerebellar tonsils and the size of the cisterna magna were both normal. In Type 5, a partial adhesion of the arachnoid membrane around the spinal cord was shown, and the syrinx was found extended toward the rostral as well as the caudal direction of the arachnoid adhesion. The rostral end of the syrinx was sometimes changed in size during MRI examinatin. This phenomenon sustained William's theory of 'suck and slosh mechanism' of intraspinal syrinx extension. (N.K.)

  14. Interaction between lidocaine hydrochloride (with and without adrenaline) and various irrigants: A nuclear magnetic resonance analysis.

    Science.gov (United States)

    Vidhya, Nirmal; Karthikeyan, Balasubramanian Saravana; Velmurugan, Natanasabapathy; Abarajithan, Mohan; Nithyanandan, Sivasankaran

    2014-05-01

    Interaction between local anesthetic solution, lidocaine hydrochloride (with and without adrenaline), and root canal irrigants such as sodium hypochlorite (NaOCl), ethylene diamine tetra-acetic acid (EDTA), and chlorhexidine (CHX) has not been studied earlier. Hence, the purpose of this in vitro study was to evaluate the chemical interaction between 2% lidocaine hydrochloride (with and without adrenaline) and commonly used root canal irrigants, NaOCl, EDTA, and CHX. SAMPLES WERE DIVIDED INTO EIGHT EXPERIMENTAL GROUPS: Group I-Lidocaine hydrochloride (with adrenaline)/3% NaOCl, Group II-Lidocaine hydrochloride (with adrenaline)/17% EDTA, Group III- Lidocaine hydrochloride (with adrenaline)/2% CHX, Group IV-Lidocaine hydrochloride (without adrenaline)/3% NaOCl, Group V-Lidocaine hydrochloride (without adrenaline)/17% EDTA, Group VI-Lidocaine hydrochloride (without adrenaline)/2% CHX, and two control groups: Group VII-Lidocaine hydrochloride (with adrenaline)/deionized water and Group VIII-Lidocaine hydrochloride (without adrenaline)/deionized water. The respective solutions of various groups were mixed in equal proportions (1 ml each) and observed for precipitate formation. Chemical composition of the formed precipitate was then analysed by nuclear magnetic resonance spectroscopy (NMR) and confirmed with diazotation test. In groups I and IV, a white precipitate was observed in all the samples on mixing the respective solutions, which showed a color change to reddish brown after 15 minutes. This precipitate was then analysed by NMR spectroscopy and was observed to be 2,6-xylidine, a reported toxic compound. The experimental groups II, III, V, and VI and control groups VII and VIII showed no precipitate formation in any of the respective samples, until 2 hours. Interaction between lidocaine hydrochloride (with and without adrenaline) and NaOCl showed precipitate formation containing 2,6-xylidine, a toxic compound.

  15. Proceedings of the 4. Brazilian meeting on magnetic resonance. Abstracts

    International Nuclear Information System (INIS)

    1996-01-01

    This publication contains the abstracts of the papers presented during the 4. Brazilian meeting on magnetic resonance and also during the Course on advances in nuclear magnetic resonance. Works on the areas of materials, rare earths, polymers, structural chemical analysis and NMR spectra are presented

  16. Theory of error for target factor analysis with applications to mass spectrometry and nuclear magnetic resonance spectrometry

    International Nuclear Information System (INIS)

    Malinowski, E.R.

    1978-01-01

    Based on the theory of error for abstract factor analysis described earlier, a theory of error for target factor analysis is developed. The theory shows how the error in the data matrix mixes with the error in the target test vector. The apparent error in a target test is found to be a vector sum of the real error in the target vector and the real error in the predicted vector. The theory predicts the magnitudes of these errors without requiring any a priori knowledge of the error in the data matrix or the target vector. A reliability function and a spoil function are developed for the purpose of assessing the validity and the worthiness of a target vector. Examples from model data, mass spectrometry and nuclear magnetic resonance spectrometry are presented. (Auth.)

  17. The nuclear magnetic resonance well logging

    International Nuclear Information System (INIS)

    Zhang Yumin; Shen Huitang

    2003-01-01

    In this paper, the characteristic of the nuclear magnetic resonance logging is described at first. Then its development and its principle is presented. Compared with the nuclear magnetic resonance spectrometer, the magnet techniques is the first question that we must solve in the manufacture of the NMR well logging

  18. Magnetic resonance imaging at Rikshospitalet

    International Nuclear Information System (INIS)

    Smith, H.J.

    1990-01-01

    During the first 18 months of operations of the nuclear magnetic resonance (NMR) unit at Rikshospitalet, 1453 NMR examinations have been performed on 1431 patients. 64% of the time has been devoted to examinations of the central nervous system and spine in children and adults, 9% of the time has been used on non-neuroradiology pediatric patients, while the rest of the time has been spent equally on ear, nose and throat, thoracic (including cardiac) and abdominal examinations in adult patients. The indications for doing NMR at Rikshospitalet are listed and discussed, and it is concluded that NMR has proved to be useful at several conditions in most organ systems. 15 refs

  19. Magnetic resonance imaging in psychiatry

    International Nuclear Information System (INIS)

    Mann, K.

    1993-01-01

    Diagnosis and research in psychiatry are increasingly availing themselves of magnetic resonance imaging (MRI). In comparison to computed tomography (CT), this offers the combined benefits of no exposure to radiation, high resolution, artefact-free display of structures near bone, and a sharp contrast between the grey and white brain matter, with freedom to select the section. With the exception of very anxious patients, MRI will gradually replace CT scans for a wide range of differential diagnostic investigations. Its superiority in systematic studies of psychiatric patients with discrete cerebral parenchyma lesions is already considered proven. This is illustrated on the basis of research into schizophrenia and alcoholism. (orig.) [de

  20. 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

  1. Independent component analysis-based artefact reduction: application to the electrocardiogram for improved magnetic resonance imaging triggering

    International Nuclear Information System (INIS)

    Oster, Julien; Pietquin, Olivier; Felblinger, Jacques; Abächerli, Roger; Kraemer, Michel

    2009-01-01

    Electrocardiogram (ECG) is required during magnetic resonance (MR) examination for monitoring patients under anaesthesia or with heart diseases and for synchronizing image acquisition with heart activity (triggering). Accurate and fast QRS detection is therefore desirable, but this task is complicated by artefacts related to the complex MR environment (high magnetic field, radio-frequency pulses and fast switching magnetic gradients). Specific signal processing has been proposed, whether using specific MR QRS detectors or ECG denoising methods. Most state-of-the-art techniques use a connection to the MR system for achieving their task, which is a major drawback since access to the MR system is often restricted. This paper introduces a new method for on-line ECG signal enhancement, called ICARE, which takes advantage of using multi-lead ECG and does not require any connection to the MR system. It is based on independent component analysis (ICA) and applied in real time. This algorithm yields accurate QRS detection for efficient triggering

  2. Symbol Digit Modalities Test adaptation for Magnetic Resonance Imaging environment: A systematic review and meta-analysis.

    Science.gov (United States)

    Silva, P H R; Spedo, C T; Barreira, A A; Leoni, R F

    2018-02-01

    The Symbol Digit Modalities Test (SDMT) is widely used for cognitive evaluation of information processing speed (IPS), required in many cognitive operations. Despite being unspecific for different neurological disorders, it is sensitive to assess impaired performance related to stroke, Parkinson's disease, traumatic brain injury, and multiple sclerosis. However, in addition to evaluate the presence and severity of IPS impairment, it is of interest to determine the localization and integration of brain regions responsible for the functions assessed by the SDMT. To review the studies that adapted the SDMT to the magnetic resonance environment and obtain the brain areas associated with the performance of the task in healthy subjects with a meta-analysis. A systematic review was performed using ten studies published between 1990 and 2017, and selected from four databases. All studies included participants of both genders and age between 18 and 50 years, used Functional Magnetic Resonance Imaging (fMRI) and SDMT adaptation and reported brain regions associated with the task. Six of them also reported the region coordinates in a standard space, so they were included in a meta-analysis. Activation Likelihood Estimation algorithm, with significance for p < 0.05 corrected for multiple comparisons, was used to identify areas that are robustly related to the performance of the SDMT. The areas predominantly reported in the studies of our meta-analysis were regions of the frontoparietal attentional network and occipital cortex, as well as cuneus, precuneus, and cerebellum. Individually all regions that survived the statistical threshold are consistent with what is expected after reviewing prospective studies. The present study allowed the identification of brain areas activated during the performance of the SDMT in healthy subjects, and therefore it will help understanding the differences in brain activation by this task in clinical populations. Moreover, it may guide future

  3. Analysis of clinical course and magnetic resonance imaging of posttraumatic diabetes insipidus

    International Nuclear Information System (INIS)

    Inoue, Yoshiaki; Hirota, Tetsuya; Kohno, Masanobu; Iwai, Atsushi; Abe, Yoshio; Ikeuchi, Hisashi; Yoshioka, Toshiharu

    2002-01-01

    We analyzed the relationship between posttraumatic diabetes insipidus (DI) onset and magnetic resonance imaging (MRI). In the last 5 years, 13 survivors of head injury were diagnosed with DI. We divided them into 2 groups, early and delayed, by DI onset. The early group consisted of 5 patients diagnosed with DI within 12 hours of injury. The delayed group consisted of 8 diagnosed after 12 hours or more. We analyzed differences between groups for factors such as Glasgow coma scale (GCS) on admission, Glasgow outcome scale (GOS) at discharge, DI duration, intracranial pressure (ICP) when diagnosed with DI, maximum ICP during observation, and MRI findings. In the early group, mean onset of DI was about 40 hours earlier than that in the delayed group, 7±2 vs. 47±19 hours, p<0.05. No significant differences were seen between groups for GCS, ISS, or GOS. Although no significant difference was seen in ICP, barbiturate therapy was needed in 7 cases, craniotomy in 4, and hypothermia therapy in 5 to control ICP in the delayed group. Barbiturate therapy was needed in only 2 cases and no indications were seen for craniotomy or hypothermia therapy in the early group. All cases in the delayed group recovered from DI within 3 weeks, but 3 in the early group were diagnosed with permanent DI and 1 needed antidiuretic hormone (ADH) during 75 days. All of the early group was recognized to have hypothalamic injury and diffuse axonal injury in MRI, but none in the delayed group was recognized for these MRI findings. In the delayed group, the high-intensity signal of the posterior pituitary gland in T1 weighted MRI, thought to represent the granule of ADH, disappeared in the early period and reappeared gradually after recovery from DI, but this signal did not reappear in the early group. We therefore conducted that the crucial cause of posttraumatic DI in the early group is direct hypothalamic injury, perhaps due to diffuse axonal injury, and that in the delayed group, secondary

  4. Analysis of clinical course and magnetic resonance imaging of posttraumatic diabetes insipidus

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Yoshiaki; Hirota, Tetsuya; Kohno, Masanobu; Iwai, Atsushi; Abe, Yoshio; Ikeuchi, Hisashi; Yoshioka, Toshiharu [Osaka Prefectural General Hospital (Japan)

    2002-06-01

    We analyzed the relationship between posttraumatic diabetes insipidus (DI) onset and magnetic resonance imaging (MRI). In the last 5 years, 13 survivors of head injury were diagnosed with DI. We divided them into 2 groups, early and delayed, by DI onset. The early group consisted of 5 patients diagnosed with DI within 12 hours of injury. The delayed group consisted of 8 diagnosed after 12 hours or more. We analyzed differences between groups for factors such as Glasgow coma scale (GCS) on admission, Glasgow outcome scale (GOS) at discharge, DI duration, intracranial pressure (ICP) when diagnosed with DI, maximum ICP during observation, and MRI findings. In the early group, mean onset of DI was about 40 hours earlier than that in the delayed group, 7{+-}2 vs. 47{+-}19 hours, p<0.05. No significant differences were seen between groups for GCS, ISS, or GOS. Although no significant difference was seen in ICP, barbiturate therapy was needed in 7 cases, craniotomy in 4, and hypothermia therapy in 5 to control ICP in the delayed group. Barbiturate therapy was needed in only 2 cases and no indications were seen for craniotomy or hypothermia therapy in the early group. All cases in the delayed group recovered from DI within 3 weeks, but 3 in the early group were diagnosed with permanent DI and 1 needed antidiuretic hormone (ADH) during 75 days. All of the early group was recognized to have hypothalamic injury and diffuse axonal injury in MRI, but none in the delayed group was recognized for these MRI findings. In the delayed group, the high-intensity signal of the posterior pituitary gland in T1 weighted MRI, thought to represent the granule of ADH, disappeared in the early period and reappeared gradually after recovery from DI, but this signal did not reappear in the early group. We therefore conducted that the crucial cause of posttraumatic DI in the early group is direct hypothalamic injury, perhaps due to diffuse axonal injury, and that in the delayed group, secondary

  5. Fusion of 4D echocardiography and cine cardiac magnetic resonance volumes using a salient spatio-temporal analysis

    Science.gov (United States)

    Atehortúa, Angélica; Garreau, Mireille; Romero, Eduardo

    2017-11-01

    An accurate left (LV) and right ventricular (RV) function quantification is important to support evaluation, diagnosis and prognosis of cardiac pathologies such as the cardiomyopathies. Currently, diagnosis by ultrasound is the most cost-effective examination. However, this modality is highly noisy and operator dependent, hence prone to errors. Therefore, fusion with other cardiac modalities may provide complementary information and improve the analysis of the specific pathologies like cardiomyopathies. This paper proposes an automatic registration between two complementary modalities, 4D echocardiography and Magnetic resonance images, by mapping both modalities to a common space of salience where an optimal registration between them is estimated. The obtained matrix transformation is then applied to the MRI volume which is superimposed to the 4D echocardiography. Manually selected marks in both modalities are used to evaluate the precision of the superimposition. Preliminary results, in three evaluation cases, show the distance between these marked points and the estimated with the transformation is about 2 mm.

  6. 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.

  7. Magnetic resonance imaging of Parkinsonism

    International Nuclear Information System (INIS)

    Mukai, Eiichiro; Makino, Naoki; Fujishiro, Kenichiro.

    1989-01-01

    We have analyzed magnetic resonance images in 33 patients; 18 patients with Parkinson's disease, 1 patient with diurnally fluctuating progressive dystonia, 1 patient with pure akinesia, 6 patients with multiple system atrophy, 1 patient with flunarizine induced parkinsonism, and 4 patients with unclassified parkinsonism. The MR images were obtained using a 1.5-T GE MR System. A spin-echo pulse sequence was used with a TE of 30 msec and 80 msec and a TR of 2000 msec. No signal abnormalities were seen in any patient with Parkinson's disease but 3 showed slightly decreased signal intensity of the putamen on T2-weighted sequences. Patients with diurnally fluctuating progressive dystonia and pure akinesia evidensed no abnormal findings. All six patients with multiple system atrophy demonstrated decreased signal intensity of the putamen, particularly along their lateral and posterior portions, and an enlarged substantia nigra. Atrophy of the pons and cerebellum was detected in all cases with multiple system atrophy. One case of flunarizine induced parkinsonism showed slightly decreased signal intensity of the putamen. Four cases of unclassified parkinsonism showed decreased signal in the putamen on T2-weighted sequences. Magnetic resonance imaging has the potential to become a useful diagnostic tool in the management of parkinsonism. (author)

  8. Magnetic resonance imaging of Parkinsonism

    Energy Technology Data Exchange (ETDEWEB)

    Mukai, Eiichiro [National Hospital of Nagoya (Japan); Makino, Naoki; Fujishiro, Kenichiro

    1989-06-01

    We have analyzed magnetic resonance images in 33 patients; 18 patients with Parkinson's disease, 1 patient with diurnally fluctuating progressive dystonia, 1 patient with pure akinesia, 6 patients with multiple system atrophy, 1 patient with flunarizine induced parkinsonism, and 4 patients with unclassified parkinsonism. The MR images were obtained using a 1.5-T GE MR System. A spin-echo pulse sequence was used with a TE of 30 msec and 80 msec and a TR of 2000 msec. No signal abnormalities were seen in any patient with Parkinson's disease but 3 showed slightly decreased signal intensity of the putamen on T2-weighted sequences. Patients with diurnally fluctuating progressive dystonia and pure akinesia evidensed no abnormal findings. All six patients with multiple system atrophy demonstrated decreased signal intensity of the putamen, particularly along their lateral and posterior portions, and an enlarged substantia nigra. Atrophy of the pons and cerebellum was detected in all cases with multiple system atrophy. One case of flunarizine induced parkinsonism showed slightly decreased signal intensity of the putamen. Four cases of unclassified parkinsonism showed decreased signal in the putamen on T2-weighted sequences. Magnetic resonance imaging has the potential to become a useful diagnostic tool in the management of parkinsonism. (author).

  9. Migraine and magnetic resonance spectroscopy

    DEFF Research Database (Denmark)

    Younis, Samaira; Hougaard, Anders; Vestergaard, Mark B.

    2017-01-01

    Purpose of review: To present an updated and streamlined overview of the metabolic and biochemical aspect of the migraine pathophysiology based on findings from phosphorous (31P) and hydrogen (1H) magnetic resonance spectroscopy (MRS) studies. Recent findings: Despite of the variation in the meth......Purpose of review: To present an updated and streamlined overview of the metabolic and biochemical aspect of the migraine pathophysiology based on findings from phosphorous (31P) and hydrogen (1H) magnetic resonance spectroscopy (MRS) studies. Recent findings: Despite of the variation...... in the methodology and quality of the MRS migraine studies over time, some results were consistent and reproducible. 31P-MRS studies suggested reduced availability of neuronal energy and implied a mitochondrial dysfunction in the migraine brain. 1H-MRS studies reported interictal abnormalities in the excitatory...... and inhibitory neurotransmitters, glutamate and g-aminobutyric acid (GABA), suggesting persistent altered excitability in migraine patients. N-Acetylaspartate levels were decreased in migraine, probably due to a mitochondrial dysfunction and abnormal energy metabolism. The reported abnormalities may increase...

  10. Magnetic resonance imaging of chemistry.

    Science.gov (United States)

    Britton, Melanie M

    2010-11-01

    Magnetic resonance imaging (MRI) has long been recognized as one of the most important tools in medical diagnosis and research. However, MRI is also well placed to image chemical reactions and processes, determine the concentration of chemical species, and look at how chemistry couples with environmental factors, such as flow and heterogeneous media. This tutorial review will explain how magnetic resonance imaging works, reviewing its application in chemistry and its ability to directly visualise chemical processes. It will give information on what resolution and contrast are possible, and what chemical and physical parameters can be measured. It will provide examples of the use of MRI to study chemical systems, its application in chemical engineering and the identification of contrast agents for non-clinical applications. A number of studies are presented including investigation of chemical conversion and selectivity in fixed-bed reactors, temperature probes for catalyst pellets, ion mobility during tablet dissolution, solvent dynamics and ion transport in Nafion polymers and the formation of chemical waves and patterns.

  11. Pattern recognition analysis of proton nuclear magnetic resonance spectra of brain tissue extracts from rats anesthetized with propofol or isoflurane.

    Directory of Open Access Journals (Sweden)

    Hiroshi Kawaguchi

    Full Text Available BACKGROUND: General anesthesia is routinely used as a surgical procedure and its safety has been endorsed by clinical outcomes; however, its effects at the molecular level have not been elucidated. General anesthetics influence glucose metabolism in the brain. However, the effects of anesthetics on brain metabolites other than those related to glucose have not been well characterized. We used a pattern recognition analysis of proton nuclear magnetic resonance spectra to visualize the changes in holistic brain metabolic phenotypes in response to the widely used intravenous anesthetic propofol and the volatile anesthetic isoflurane. METHODOLOGY/PRINCIPAL FINDINGS: Rats were randomized into five groups (n = 7 each group. Propofol and isoflurane were administered to two groups each, for 2 or 6 h. The control group received no anesthesia. Brains were removed directly after anesthesia. Hydrophilic compounds were extracted from excised whole brains and measured by proton nuclear magnetic resonance spectroscopy. All spectral data were processed and analyzed by principal component analysis for comparison of the metabolite profiles. Data were visualized by plotting principal component (PC scores. In the plots, each point represents an individual sample. The propofol and isoflurane groups were clustered separately on the plots, and this separation was especially pronounced when comparing the 6-h groups. The PC scores of the propofol group were clearly distinct from those of the control group, particularly in the 6-h group, whereas the difference in PC scores was more subtle in the isoflurane group and control groups. CONCLUSIONS/SIGNIFICANCE: The results of the present study showed that propofol and isoflurane exerted differential effects on holistic brain metabolism under anesthesia.

  12. Influence of Spatial Resolution in Three-dimensional Cine Phase Contrast Magnetic Resonance Imaging on the Accuracy of Hemodynamic Analysis.

    Science.gov (United States)

    Fukuyama, Atsushi; Isoda, Haruo; Morita, Kento; Mori, Marika; Watanabe, Tomoya; Ishiguro, Kenta; Komori, Yoshiaki; Kosugi, Takafumi

    2017-10-10

    We aim to elucidate the effect of spatial resolution of three-dimensional cine phase contrast magnetic resonance (3D cine PC MR) imaging on the accuracy of the blood flow analysis, and examine the optimal setting for spatial resolution using flow phantoms. The flow phantom has five types of acrylic pipes that represent human blood vessels (inner diameters: 15, 12, 9, 6, and 3 mm). The pipes were fixed with 1% agarose containing 0.025 mol/L gadolinium contrast agent. A blood-mimicking fluid with human blood property values was circulated through the pipes at a steady flow. Magnetic resonance (MR) images (three-directional phase images with speed information and magnitude images for information of shape) were acquired using the 3-Tesla MR system and receiving coil. Temporal changes in spatially-averaged velocity and maximum velocity were calculated using hemodynamic analysis software. We calculated the error rates of the flow velocities based on the volume flow rates measured with a flowmeter and examined measurement accuracy. When the acrylic pipe was the size of the thoracicoabdominal or cervical artery and the ratio of pixel size for the pipe was set at 30% or lower, spatially-averaged velocity measurements were highly accurate. When the pixel size ratio was set at 10% or lower, maximum velocity could be measured with high accuracy. It was difficult to accurately measure maximum velocity of the 3-mm pipe, which was the size of an intracranial major artery, but the error for spatially-averaged velocity was 20% or less. Flow velocity measurement accuracy of 3D cine PC MR imaging for pipes with inner sizes equivalent to vessels in the cervical and thoracicoabdominal arteries is good. The flow velocity accuracy for the pipe with a 3-mm-diameter that is equivalent to major intracranial arteries is poor for maximum velocity, but it is relatively good for spatially-averaged velocity.

  13. Analysis of DNA Double-Strand Breaks and Cytotoxicity after 7 Tesla Magnetic Resonance Imaging of Isolated Human Lymphocytes

    Science.gov (United States)

    Guttek, Karina; Hartig, Roland; Godenschweger, Frank; Roggenbuck, Dirk; Ricke, Jens; Reinhold, Dirk; Speck, Oliver

    2015-01-01

    The global use of magnetic resonance imaging (MRI) is constantly growing and the field strengths increasing. Yet, only little data about harmful biological effects caused by MRI exposure are available and published research analyzing the impact of MRI on DNA integrity reported controversial results. This in vitro study aimed to investigate the genotoxic and cytotoxic potential of 7 T ultra-high-field MRI on isolated human peripheral blood mononuclear cells. Hence, unstimulated mononuclear blood cells were exposed to 7 T static magnetic field alone or in combination with maximum permissible imaging gradients and radiofrequency pulses as well as to ionizing radiation during computed tomography and γ-ray exposure. DNA double-strand breaks were quantified by flow cytometry and automated microscopy analysis of immunofluorescence stained γH2AX. Cytotoxicity was studied by CellTiter-Blue viability assay and [3H]-thymidine proliferation assay. Exposure of unstimulated mononuclear blood cells to 7 T static magnetic field alone or combined with varying gradient magnetic fields and pulsed radiofrequency fields did not induce DNA double-strand breaks, whereas irradiation with X- and γ-rays led to a dose-dependent induction of γH2AX foci. The viability assay revealed a time- and dose-dependent decrease in metabolic activity only among samples exposed to γ-radiation. Further, there was no evidence for altered proliferation response after cells were exposed to 7 T MRI or low doses of ionizing radiation (≤ 0.2 Gy). These findings confirm the acceptance of MRI as a safe non-invasive diagnostic imaging tool, but whether MRI can induce other types of DNA lesions or DNA double-strand breaks during altered conditions still needs to be investigated. PMID:26176601

  14. Advances in mechanical detection of magnetic resonance

    International Nuclear Information System (INIS)

    Kuehn, Seppe; Hickman, Steven A.; Marohn, John A.

    2008-01-01

    The invention and initial demonstration of magnetic resonance force microscopy (MRFM) in the early 1990s launched a renaissance of mechanical approaches to detecting magnetic resonance. This article reviews progress made in MRFM in the last decade, including the demonstration of scanned probe detection of magnetic resonance (electron spin resonance, ferromagnetic resonance, and nuclear magnetic resonance) and the mechanical detection of electron spin resonance from a single spin. Force and force-gradient approaches to mechanical detection are reviewed and recent related work using attonewton sensitivity cantilevers to probe minute fluctuating electric fields near surfaces is discussed. Given recent progress, pushing MRFM to single proton sensitivity remains an exciting possibility. We will survey some practical and fundamental issues that must be resolved to meet this challenge.

  15. Magnetic resonance imaging: hazard, risk and safety

    International Nuclear Information System (INIS)

    Narayan, Pradeep; Suri, S.; Singh, P.

    2001-01-01

    The hazard and risk associated with magnetic resonance imaging is a matter of concern. In 1982, the Food and Drug Administration (FDA), USA issued guidelines to Hospital's Investigational Review Board (IRBs) in 'Guidelines for Evaluating Electromagnetic Exposure Risks for Trials of Clinical Nuclear Magnetic Resonance (NMR)'. In 1997, the Berufsgenossenschaft (BG), professional association for precision engineering and electronics of Germany, in their preliminary proposal for safety limits extended their concerns on static magnetic field. Owing to both time varying and static magnetic fields applied in Magnetic Resonance Imaging (MRI) this became of immediate concern to user community to assess the potential hazard and risk associated with the NMR system

  16. Magnetic resonance imaging of Parkinsonism

    International Nuclear Information System (INIS)

    Nakamura, Yusaku; Takahashi, Mitsuo; Kitaguchi, Masataka; Akaneya, Yukio; Mitui, Yoshiyuki; Tanaka, Hisashi

    1991-01-01

    We studied eighteen patients affected by Parkinsonism with symptoms of tremor, bradykinesia, or rigidity using magnetic resonance imaging (MRI). Patients ranged in age from 34 to 80 years (mean 62.8±11.6 years), and the duration of their disease had been 3.8±3.2 years. MRI examinations were performed with Shimazu and Siemens superconducting magnets, operating at 0.5 and 1.5 T magnetic fields, respectively. Both T 1 - and T 2 -weighted spin echo (SE) pulse sequences were used. In eight patients (44.4%), MRI demonstrated bilateral multiple lacunar infarction of the basal ganglia. The most common abnormality identified was multiple, bilateral lacunar infarcts in the lateral portion of the putamen. The average size of the lacunar infarction of the putamen was less than half that of the entire putamen. Patients with multiple lacunar infarction were significantly older than the other patients and had lower Yahr's scores. The clinical symptoms of patients with bilateral multiple lacunar infarction of the basal ganglia were compatible with the diagnosis of arteriosclerotic Parkinsonism of akinetic rigid type. It has been suggested that multiple lacunar infarction of the basal ganglia may have led to Parkinsonism in these patients. (author)

  17. Nuclear magnetic resonance imaging method

    International Nuclear Information System (INIS)

    Johnson, G.; MacDonald, J.; Hutchison, S.; Eastwood, L.M.; Redpath, T.W.T.; Mallard, J.R.

    1984-01-01

    A method of deriving three dimensional image information from an object using nuclear magnetic resonance signals comprises subjecting the object to a continuous, static magnetic field and carrying out the following set of sequential steps: 1) exciting nuclear spins in a selected volume (90deg pulse); 2) applying non-aligned first, second and third gradients of the magnetic field; 3) causing the spins to rephase periodically by reversal of the first gradient to produce spin echoes, and applying pulses of the second gradient prior to every read-out of an echo signal from the object, to differently encode the spin in the second gradient direction for each read-out signal. The above steps 1-3 are then successively repeated with different values of gradient of the third gradient, there being a recovery interval between the repetition of successive sets of steps. Alternate echoes only are read out, the other echoes being time-reversed and ignored for convenience. The resulting signals are appropriately sampled, set out in an array and subjected to three dimensional Fourier transformation. (author)

  18. Fourier Transform Mass Spectrometry and Nuclear Magnetic Resonance Analysis for the Rapid and Accurate Characterization of Hexacosanoylceramide.

    Science.gov (United States)

    Ross, Charles W; Simonsick, William J; Bogusky, Michael J; Celikay, Recep W; Guare, James P; Newton, Randall C

    2016-06-28

    Ceramides are a central unit of all sphingolipids which have been identified as sites of biological recognition on cellular membranes mediating cell growth and differentiation. Several glycosphingolipids have been isolated, displaying immunomodulatory and anti-tumor activities. These molecules have generated considerable interest as potential vaccine adjuvants in humans. Accurate analyses of these and related sphingosine analogues are important for the characterization of structure, biological function, and metabolism. We report the complementary use of direct laser desorption ionization (DLDI), sheath flow electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) and high-field nuclear magnetic resonance (NMR) analysis for the rapid, accurate identification of hexacosanoylceramide and starting materials. DLDI does not require stringent sample preparation and yields representative ions. Sheath-flow ESI yields ions of the product and byproducts and was significantly better than monospray ESI due to improved compound solubility. Negative ion sheath flow ESI provided data of starting materials and products all in one acquisition as hexacosanoic acid does not ionize efficiently when ceramides are present. NMR provided characterization of these lipid molecules complementing the results obtained from MS analyses. NMR data was able to differentiate straight chain versus branched chain alkyl groups not easily obtained from mass spectrometry.

  19. Fourier Transform Mass Spectrometry and Nuclear Magnetic Resonance Analysis for the Rapid and Accurate Characterization of Hexacosanoylceramide

    Directory of Open Access Journals (Sweden)

    Charles W. Ross

    2016-06-01

    Full Text Available Ceramides are a central unit of all sphingolipids which have been identified as sites of biological recognition on cellular membranes mediating cell growth and differentiation. Several glycosphingolipids have been isolated, displaying immunomodulatory and anti-tumor activities. These molecules have generated considerable interest as potential vaccine adjuvants in humans. Accurate analyses of these and related sphingosine analogues are important for the characterization of structure, biological function, and metabolism. We report the complementary use of direct laser desorption ionization (DLDI, sheath flow electrospray ionization (ESI Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS and high-field nuclear magnetic resonance (NMR analysis for the rapid, accurate identification of hexacosanoylceramide and starting materials. DLDI does not require stringent sample preparation and yields representative ions. Sheath-flow ESI yields ions of the product and byproducts and was significantly better than monospray ESI due to improved compound solubility. Negative ion sheath flow ESI provided data of starting materials and products all in one acquisition as hexacosanoic acid does not ionize efficiently when ceramides are present. NMR provided characterization of these lipid molecules complementing the results obtained from MS analyses. NMR data was able to differentiate straight chain versus branched chain alkyl groups not easily obtained from mass spectrometry.

  20. Resonant diffuse X-ray scattering from magnetic multilayers

    International Nuclear Information System (INIS)

    Spezzani, Carlo; Torelli, Piero; Delaunay, Renaud; Hague, C.F.; Petroff, Frederic; Scholl, Andreas; Gullikson, E.M.; Sacchi, Maurizio

    2004-01-01

    We have measured field-dependent resonant diffuse scattering from a magnetoresistive Co/Cu multilayer. We have observed that the magnetic domain size in zero field depends on the magnetic history of the sample. The results of the X-ray scattering analysis have been compared to PEEM images of the magnetic domains

  1. Texture analysis of torn rotator cuff on preoperative magnetic resonance arthrography as a predictor of postoperative tendon status

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Yeon Ah; Lee, Guen Young; Lee, Joon Woo; Lee, Eugene; Kim, Boh Young; Kim, Su Jin; Ahn, Joong Mo; Kang, Heung Sik [Dept. of Radiology, Seoul National University Bundang Hospital, Seongnam (Korea, Republic of)

    2017-08-01

    To evaluate texture data of the torn supraspinatus tendon (SST) on preoperative T2-weighted magnetic resonance arthrography (MRA) using the gray-level co-occurrence matrix (GLCM) for prediction of post-operative tendon state. Fifty patients who underwent arthroscopic rotator cuff repair for full-thickness tears of the SST were included in this retrospective study. Based on 1-year follow-up, magnetic resonance imaging showed that 30 patients had intact SSTs, and 20 had rotator cuff retears. Using GLCM, two radiologists measured independently the highest signal intensity area of the distal end of the torn SST on preoperative T2-weighted MRA, which were compared between two groups.The relationships with other well-known prognostic factors, including age, tear size (anteroposterior dimension), retraction size (mediolateral tear length), grade of fatty degeneration of the SST and infraspinatus tendon, and arthroscopic fixation technique (single or double row), also were evaluated. Of all the GLCM features, the retear group showed significantly higher entropy (p < 0.001 and p = 0.001), variance (p = 0.030 and 0.011), and contrast (p = 0.033 and 0.012), but lower angular second moment (p < 0.001 and p = 0.002) and inverse difference moment (p = 0.027 and 0.027), as well as larger tear size (p = 0.001) and retraction size (p = 0.002) than the intact group. Retraction size (odds ratio [OR] = 3.053) and entropy (OR = 17.095) were significant predictors. Texture analysis of torn SSTs on preoperative T2-weighted MRA using the GLCM may be helpful to predict postoperative tendon state after rotator cuff repair.

  2. [Analysis of experience in the use of dynamic pelvic magnetic resonance imaging in the assessment of obstructive defaecation syndrome].

    Science.gov (United States)

    Martín Martín, Gonzalo; García Armengol, Juan; Roig Vila, José Vicente; García Coret, María José; Martínez Sanjuán, Vicente; Almela Notari, Pedro; Mínguez Pérez, Miguel

    2012-05-01

    The aetiological diagnosis of obstructive defaecation syndrome (ODS) requires, among others, imaging tests. The purpose of this study is to descriptively analyse and compare the findings of dynamic pelvic magnetic resonance imaging (DPMRI) with the clinical examinations in patients with ODS. A prospective comparative study was made between the physical examination and the DPMRI, with a descriptive analysis of the results. A total of 30 patients were included (2 males and 28 females), with a median age of 60 (range 23-76) years, with symptoms of ODS. An anamnesis and detailed physical examination and a DPMRI were performed on all of them. Functional (anismus) and morphological changes (rectocele, enterocele, intussusception, etc.), were analysed. The physical examination did not detect anomalies in 6 (20%) patients. A rectocele was diagnosed in 21 (70%) of the cases, and 2 (6.7%) a rectal mucosal prolapse. The DPMRI showed evidence of pelvic floor laxity in 22 (73.3%) cases, an enterocele in 4 (13.3%), a sigmoidocele in 2 (6.7%), intussusception in 8 (26.7%), rectal mucosal prolapse in 4 (13.3%), anismus in 3 (10%), and a cystocele in 4 (13.3%). The rectocele was the most frequent diagnosis, being given in 26 (86.6%) patients. Magnetic resonance imaging provides an overall pelvic assessment with good definition of the tissues, and does not use ionising radiation, is well tolerated, and provides us with complementary information to arrive at the diagnosis, and establish the best treatment for ODS. Larger studies comparing videodefaecography (VD), currently considered the Gold Standard technique, are needed to be able to demonstrate whether it is superior or not to DPMRI. Copyright © 2011 AEC. Published by Elsevier Espana. All rights reserved.

  3. Texture analysis of torn rotator cuff on preoperative magnetic resonance arthrography as a predictor of postoperative tendon status

    International Nuclear Information System (INIS)

    Kang, Yeon Ah; Lee, Guen Young; Lee, Joon Woo; Lee, Eugene; Kim, Boh Young; Kim, Su Jin; Ahn, Joong Mo; Kang, Heung Sik

    2017-01-01

    To evaluate texture data of the torn supraspinatus tendon (SST) on preoperative T2-weighted magnetic resonance arthrography (MRA) using the gray-level co-occurrence matrix (GLCM) for prediction of post-operative tendon state. Fifty patients who underwent arthroscopic rotator cuff repair for full-thickness tears of the SST were included in this retrospective study. Based on 1-year follow-up, magnetic resonance imaging showed that 30 patients had intact SSTs, and 20 had rotator cuff retears. Using GLCM, two radiologists measured independently the highest signal intensity area of the distal end of the torn SST on preoperative T2-weighted MRA, which were compared between two groups.The relationships with other well-known prognostic factors, including age, tear size (anteroposterior dimension), retraction size (mediolateral tear length), grade of fatty degeneration of the SST and infraspinatus tendon, and arthroscopic fixation technique (single or double row), also were evaluated. Of all the GLCM features, the retear group showed significantly higher entropy (p < 0.001 and p = 0.001), variance (p = 0.030 and 0.011), and contrast (p = 0.033 and 0.012), but lower angular second moment (p < 0.001 and p = 0.002) and inverse difference moment (p = 0.027 and 0.027), as well as larger tear size (p = 0.001) and retraction size (p = 0.002) than the intact group. Retraction size (odds ratio [OR] = 3.053) and entropy (OR = 17.095) were significant predictors. Texture analysis of torn SSTs on preoperative T2-weighted MRA using the GLCM may be helpful to predict postoperative tendon state after rotator cuff repair

  4. Three-dimensional forward solver and its performance analysis for magnetic resonance electrical impedance tomography (MREIT) using recessed electrodes

    International Nuclear Information System (INIS)

    Lee, Byung Il; Oh, Suk Hoon; Woo, Eung Je; Lee, Soo Yeol; Cho, Min Hyoung; Kwon, Ohin; Seo, Jin Keun; Lee, June-Yub; Baek, Woon Sik

    2003-01-01

    In magnetic resonance electrical impedance tomography (MREIT), we try to reconstruct a cross-sectional resistivity (or conductivity) image of a subject. When we inject a current through surface electrodes, it generates a magnetic field. Using a magnetic resonance imaging (MRI) scanner, we can obtain the induced magnetic flux density from MR phase images of the subject. We use recessed electrodes to avoid undesirable artefacts near electrodes in measuring magnetic flux densities. An MREIT image reconstruction algorithm produces cross-sectional resistivity images utilizing the measured internal magnetic flux density in addition to boundary voltage data. In order to develop such an image reconstruction algorithm, we need a three-dimensional forward solver. Given injection currents as boundary conditions, the forward solver described in this paper computes voltage and current density distributions using the finite element method (FEM). Then, it calculates the magnetic flux density within the subject using the Biot-Savart law and FEM. The performance of the forward solver is analysed and found to be enough for use in MREIT for resistivity image reconstructions and also experimental designs and validations. The forward solver may find other applications where one needs to compute voltage, current density and magnetic flux density distributions all within a volume conductor

  5. Different energy metabolism in two human small cell lung cancer subpopulations examined by 31P magnetic resonance spectroscopy and biochemical analysis in vivo and in vitro

    DEFF Research Database (Denmark)

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

    1991-01-01

    Two human small cell lung cancer tumor lines, maintained as solid tumor xenografts on nude mice and as in vitro cell cultures, were studied by in vivo 31P magnetic resonance spectroscopy and by biochemical analysis of extracts of solid tumors and cell cultures. The tumor lines CPH SCCL 54A and CPH...

  6. Three-dimensional magnetic resonance imaging analysis of hip morphology in the assessment of femoral acetabular impingement

    International Nuclear Information System (INIS)

    Kavanagh, E.C.; Read, P.; Carty, F.; Zoga, A.C.; Parvizi, J.; Morrison, W.B.

    2011-01-01

    Aim: To determine a possible association between femoral-acetabular impingement (FAI) volume and the development of labral tear using a three-dimensional (3D) model reconstruction of the acetabulum and the femoral head. Materials and methods: Magnetic resonance arthrography images of the hip in 42 patients with pain and suspected labral tear were acquired using a 1.5 T MRI machine. Using 3D analysis software, outlines of the acetabular cup and femoral head were drawn and 3D reconstruction obtained. To control for differences in patient size, ratios of acetabulum : femoral head volume (AFV) and acetabulum : femoral head surface area (AFA) were used for analysis. The association between volume of acetabulum : femoral head and FAI was investigated using ANOVA analysis. Results: There were 19 men and 23 women with a mean age of 39 years (range 18-78 years). The average AFV was 0.64 (range 0.37-1.05, SD 0.16) and AFA was 0.73 (range 0.36-1.26, SD 0.23). Herniation pit was significantly associated with a small AFV. Conclusion: Femoral neck herniation pits are associated with a low AFV. Gross volume and surface area ratios do not appear to correlate with labral tears or cartilage loss. This technique will enable more advanced analysis of morphological variations associated with FAI.

  7. Transition metal nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Pregosin, P.S.

    1991-01-01

    Transition metal NMR spectroscopy has progressed enormously in recent years. New methods, and specifically solid-state methods and new pulse sequences, have allowed access to data from nuclei with relatively low receptivities with the result that chemists have begun to consider old and new problems, previously unapproachable. Moreover, theory, computational science in particular, now permits the calculation of not just 13 C, 15 N and other light nuclei chemical shifts, but heavy main-group element and transition metals as well. These two points, combined with increasing access to high field pulsed spectrometer has produced a wealth of new data on the NMR transition metals. A new series of articles concerned with measuring, understanding and using the nuclear magnetic resonance spectra of the metals of Group 3-12 is presented. (author)

  8. Gaucher's disease: Magnetic resonance findings

    International Nuclear Information System (INIS)

    Roca, M.; Gomez-Pereda, R.; Blasco, A.; Ros, L.

    1996-01-01

    The objective is to assess the role of magnetic resonance (MR) in determining the initial extension of Gaucher's disease and its complications. A retrospective study of eight patients diagnosed as having Gaucher's disease was carried out using MR. The study focused on pelvis, hip, femur, spine, liver parenchyma and splenic parenchyma. Infiltration of the cancellous portion of the vertebral bodies was observed in all but one of the patients. Three patients presented small hemangiomas in dorsal and lumbar vertebral bodies. Pelvic bone involvement was homogeneous in four cases and spotty in two, while the pelvic marrow was normal in the two patients with no vertebral infiltration. A vascular necrosis of the femoral head was detected in two cases. MR is very useful in determining the initial extension, in the early diagnosis of complications and in managing the posttreatment marrow response to assess the therapeutic efficacy. 16 refs

  9. Fetal abdominal magnetic resonance imaging

    International Nuclear Information System (INIS)

    Brugger, Peter C.; Prayer, Daniela

    2006-01-01

    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

  10. 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.

  11. Magnetic resonance imaging in neuroradiology

    International Nuclear Information System (INIS)

    Voigt, K.; Lotx, J.W.

    1990-01-01

    Magnetic resonance imaging (MRI) is now accepted as an effective method of investigating a wide range of disorders, especially of the brain and spine. A short introduction on image contrast in MRI is given and the advantages and disadvantages for the different diseases of the brain is discussed. Excellent soft-tissue contrast, multiplanar imaging capabilities and lack of ionising radiation are conspicuous advantages, and it is now established as the investigation of choice in a large number of clinical conditions, especially when the central nervous system is involved. However, it remains only one of a series of imaging modalities. A confident provisional clinical diagnosis is essential for establishing an imaging protocol and the intention should always be to reach a definitive diagnosis in the least invasive and most cost-effective way. 7 figs., 19 refs

  12. Performance and analysis of wireless power charging system from room temperature to HTS magnet via strong resonance coupling method

    International Nuclear Information System (INIS)

    Chung, Y. D.; Lee, S. Y.; Lee, T. W.; Kim, J. S.; Lee, C. Y.

    2016-01-01

    The technology of supplying the electric power by wireless power transfer (WPT) is expected for the next generation power feeding system since it can supply the power to portable devices without any connectors through large air gap. As such a technology based on strongly coupled electromagnetic resonators is possible to deliver the large power and recharge them seamlessly; it has been considered as a noble option to wireless power charging system in the various power applications. Recently, various HTS wires have now been manufactured for demonstrations of transmission cables, motors, MAGLEV, and other electrical power components. However, since the HTS magnets have a lower index n value intrinsically, they are required to be charged from external power system through leads or internal power system. The portable area is limited as well as the cryogen system is bulkier. Thus, we proposed a novel design of wireless power charging system for superconducting HTS magnet (WPC4SM) based on resonance coupling method. As the novel system makes possible a wireless power charging using copper resonance coupled coils, it enables to portable charging conveniently in the superconducting applications. This paper presented the conceptual design and operating characteristics of WPC4SM using different shapes' copper resonance coil. The proposed system consists of four components; RF generator of 370 kHz, copper resonance coupling coils, impedance matching (IM) subsystem and HTS magnet including rectifier system

  13. Performance and analysis of wireless power charging system from room temperature to HTS magnet via strong resonance coupling method

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Y. D.; Lee, S. Y.; Lee, T. W.; Kim, J. S. [Suwon Science College, Suwon (Korea, Republic of); Lee, C. Y. [Korea Railroad Institute, Uiwang (Korea, Republic of)

    2016-03-15

    The technology of supplying the electric power by wireless power transfer (WPT) is expected for the next generation power feeding system since it can supply the power to portable devices without any connectors through large air gap. As such a technology based on strongly coupled electromagnetic resonators is possible to deliver the large power and recharge them seamlessly; it has been considered as a noble option to wireless power charging system in the various power applications. Recently, various HTS wires have now been manufactured for demonstrations of transmission cables, motors, MAGLEV, and other electrical power components. However, since the HTS magnets have a lower index n value intrinsically, they are required to be charged from external power system through leads or internal power system. The portable area is limited as well as the cryogen system is bulkier. Thus, we proposed a novel design of wireless power charging system for superconducting HTS magnet (WPC4SM) based on resonance coupling method. As the novel system makes possible a wireless power charging using copper resonance coupled coils, it enables to portable charging conveniently in the superconducting applications. This paper presented the conceptual design and operating characteristics of WPC4SM using different shapes' copper resonance coil. The proposed system consists of four components; RF generator of 370 kHz, copper resonance coupling coils, impedance matching (IM) subsystem and HTS magnet including rectifier system.

  14. 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....

  15. 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....

  16. Single voxel magnetic resonance spectroscopy in distinguishing ...

    African Journals Online (AJOL)

    Objective: Assess diagnostic utility of combined magnetic resonance imaging and magnetic resonance spectroscopy (MRI, MRS) in differentiating focal neoplastic lesions from focal non- neoplastic (infective or degenerative) brain lesions. Design: Descriptive, analytical - prospective study. Setting: The Aga Khan University ...

  17. Magnetic resonance imaging of radiation optic neuropathy

    International Nuclear Information System (INIS)

    Zimmerman, C.F.; Schatz, N.J.; Glaser, J.S.

    1990-01-01

    Three patients with delayed radiation optic neuropathy after radiation therapy for parasellar neoplasms underwent magnetic resonance imaging. The affected optic nerves and chiasms showed enlargement and focal gadopentetate dimeglumine enhancement. The magnetic resonance imaging technique effectively detected and defined anterior visual pathway changes of radionecrosis and excluded the clinical possibility of visual loss because of tumor recurrence

  18. Magnetic resonance: discovery, investigations, and applications

    International Nuclear Information System (INIS)

    Kessenikh, Aleksandr V

    2009-01-01

    The history of the development of the theoretical ideas and experimental methods of magnetic resonance, as well as the applications of these methods in modern natural science, technology, and medicine, are outlined, with allowance for the contribution of Russian researchers. An assessment of some promising trends of studies and applications of magnetic resonance is given. (from the history of physics)

  19. Contrast agents in magnetic resonance imaging

    International Nuclear Information System (INIS)

    Karadjian, V.

    1987-01-01

    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 [fr

  20. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

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

  1. Magnetic resonance imaging of hypophysis

    International Nuclear Information System (INIS)

    Malla Huesh, I. V.

    2016-01-01

    Hypothalamic-pituitary diseases represent with wide variety of symptoms in regard with changes in the endocrine function. Magnetic resonance imaging has a crucial role in detecting the morphologic appearance in physiologic conditions, malformative diseases and acquired pathologies. The MR-imaging is established as the method of choice in assessing the changes in the hypothalamic-pituitary axis. The pituitary gland is a complex structure with an important role in the homeostasis of the organism even though it is so small? It is surrounded by bony structures, vessels, nerves and the brain parenchyma. It consists of three parts - anterior called - adenohypophysis, posterior - neurohypophysis and pituitary stalk. The anterior part comprises about 75% of the gland. Computed tomography (CT) has a limited role in detecting the pituitary gland. It is mainly used in cases of elevated intracranial pressure due to suspected apoplexy. The gland's small size, relation to other structures and its soft tissue characteristic make it an accessible region of interest for detecting with MR-imaging. The lack of ionizing energy and the technical advances in the MR-methods are responsible for the creating images with better spatial resolution and signal to noise ratio. The examination is carried out on a standard protocol. It is important that thin slices are executed in sagittal and coronal planes. Performing a sequence, regarding the brain parenchyma is essential, since many malformations of the pituitary gland are associated with other congenital conditions. The examination starts with a T1W sequence to assess the normal anatomic condition of the gland. The intensity of the adenohypophysis is compared to the one in the pons. It is hypointense, whereas the neurohypophysis is hyperintense, due to the lipid neurosecretory granules transported along the hypothalamic-pituitary axis. T2W-images in coronal plane are used to evaluate the hypothalamus, pituitary stalk, optic chiasm, olfactory

  2. From raw data to data-analysis for magnetic resonance spectroscopy – the missing link: jMRUI2XML

    Czech Academy of Sciences Publication Activity Database

    Mocioiu, V.; Ortega-Martorell, S.; Olier, I.; Jabłoński, Michal; Starčuková, Jana; Lisboa, P.; Arús, C.; Julia-Sapé, M.

    2015-01-01

    Roč. 16, NOV 9 (2015), s. 378-388 ISSN 1471-2105 R&D Projects: GA MŠk(CZ) LO1212; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : magnetic resonance spectroscopy * pattern recognition * signal processing, * software development Subject RIV: JC - Computer Hardware ; Software Impact factor: 2.435, year: 2015

  3. Hepatocellular adenoma: findings at state-of-the-art magnetic resonance imaging, ultrasound, computed tomography and pathologic analysis

    International Nuclear Information System (INIS)

    Hussain, Shahid M.; Bos, Indra C. van den; Dwarkasing, Roy S.; Kuiper, Jan-Willem; Hollander, Jan den

    2006-01-01

    The purpose of this paper is to describe the most recent concepts and pertinent findings of hepatocellular adenomas, including clinical presentation, gross pathology and histology, pathogenesis and transformation into hepatocellular carcinoma (HCC), and imaging findings at ultrasound (US), computed tomography (CT), and magnetic resonance (MR) imaging. (orig.)

  4. Comparative analysis of magnetic resonance in the polaron pair recombination and the triplet exciton-polaron quenching models

    Science.gov (United States)

    Mkhitaryan, V. V.; Danilović, D.; Hippola, C.; Raikh, M. E.; Shinar, J.

    2018-01-01

    We present a comparative theoretical study of magnetic resonance within the polaron pair recombination (PPR) and the triplet exciton-polaron quenching (TPQ) models. Both models have been invoked to interpret the photoluminescence detected magnetic resonance (PLDMR) results in π -conjugated materials and devices. We show that resonance line shapes calculated within the two models differ dramatically in several regards. First, in the PPR model, the line shape exhibits unusual behavior upon increasing the microwave power: it evolves from fully positive at weak power to fully negative at strong power. In contrast, in the TPQ model, the PLDMR is completely positive, showing a monotonic saturation. Second, the two models predict different dependencies of the resonance signal on the photoexcitation power, PL. At low PL, the resonance amplitude Δ I /I is ∝PL within the PPR model, while it is ∝PL2 crossing over to PL3 within the TPQ model. On the physical level, the differences stem from different underlying spin dynamics. Most prominently, a negative resonance within the PPR model has its origin in the microwave-induced spin-Dicke effect, leading to the resonant quenching of photoluminescence. The spin-Dicke effect results from the spin-selective recombination, leading to a highly correlated precession of the on-resonance pair partners under the strong microwave power. This effect is not relevant for TPQ mechanism, where the strong zero-field splitting renders the majority of triplets off resonance. On the technical level, the analytical evaluation of the line shapes for the two models is enabled by the fact that these shapes can be expressed via the eigenvalues of a complex Hamiltonian. This bypasses the necessity of solving the much larger complex linear system of the stochastic Liouville equations. Our findings pave the way towards a reliable discrimination between the two mechanisms via cw PLDMR.

  5. Evidence for cervical muscle morphometric changes on magnetic resonance images after whiplash: A systematic review and meta-analysis.

    Science.gov (United States)

    Owers, Daniel S; Perriman, Diana M; Smith, Paul N; Neeman, Teresa; Webb, Alexandra L

    2018-02-01

    Morphometric changes to cervical musculature in whiplash associated disorder have been reported in several studies with varying results. However, the evidence is not clear because only a limited number of cohorts have been studied and one cohort has been reported in multiple publications. The aim of this study was to assess the evidence for cervical muscle morphometric changes on magnetic resonance (MR) images after whiplash using a systematic review with meta-analysis. PubMed, MEDLINE and Cochrane Library were searched without language restriction using combinations of the MeSH terms "muscles", "whiplash injuries", and "magnetic resonance imaging". Studies of acute and chronic whiplash were included if they compared whiplash and control cervical spine muscle morphometry measurements from MR images. The search identified 380 studies. After screening, eight studies describing five cohorts (one acute, three chronic, one both acute and chronic) met the inclusion criteria. Participant characteristics and outcome measures were extracted using a standard extraction format. Quality of eligible studies was assessed using the Newcastle-Ottawa Scale. Muscle cross-sectional area (CSA) and fat infiltrate (MFI) for acute and chronic whiplash cohorts were compared using mean difference and 95% confidence intervals. Meta-analysis models were created when data from more than two eligible cohorts was available, using inverse-variance random-effects models (RevMan5 version 5.3.5). Quality assessment was uniformly good but only two studies blinded the assessor. Analysis of the acute cohorts revealed no consensus with respect to CSA. MFI was not measured in the acute cohorts. Analysis of the chronic cohorts revealed CSA is probably increased in some muscles after whiplash but there is insufficient evidence to confirm whether MFI is also increased. Because the available data were limited, meta-analyses of only multifidus were performed. In chronic whiplash multifidus CSA was

  6. Multidimensionally encoded magnetic resonance imaging.

    Science.gov (United States)

    Lin, Fa-Hsuan

    2013-07-01

    Magnetic resonance imaging (MRI) 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 reconstruction performance. Here, we propose the multidimensionally encoded (MDE) MRI to map a q-dimensional object onto a p-dimensional encoding space where p > q. MDE MRI is a theoretical framework linking imaging strategies using linear and nonlinear SEMs. Using a system of eight surface SEM coils with an eight-channel radiofrequency coil array, we demonstrate the five-dimensional MDE MRI for a two-dimensional object as a further generalization of PatLoc imaging and O-space imaging. We also present a method of optimizing spatial bases in MDE MRI. Results show that MDE MRI with a higher dimensional encoding space can reconstruct images more efficiently and with a smaller reconstruction error when the k-space sampling distribution and the number of samples are controlled. Copyright © 2012 Wiley Periodicals, Inc.

  7. Cardiac magnetic resonance findings predicting mortality in patients with pulmonary arterial hypertension: a systematic review and meta-analysis

    International Nuclear Information System (INIS)

    Baggen, Vivan J.M.; Leiner, Tim; Habets, Jesse; Post, Marco C.; Dijk, Arie P. van; Sieswerda, Gertjan T.; Roos-Hesselink, Jolien W.; Boersma, Eric

    2016-01-01

    To provide a comprehensive overview of all reported cardiac magnetic resonance (CMR) findings that predict clinical deterioration in pulmonary arterial hypertension (PAH). MEDLINE and EMBASE electronic databases were systematically searched for longitudinal studies published by April 2015 that reported associations between CMR findings and adverse clinical outcome in PAH. Studies were appraised using previously developed criteria for prognostic studies. Meta-analysis using random effect models was performed for CMR findings investigated by three or more studies. Eight papers (539 patients) investigating 21 different CMR findings were included. Meta-analysis showed that right ventricular (RV) ejection fraction was the strongest predictor of mortality in PAH (pooled HR 1.23 [95 % CI 1.07-1.41], p = 0.003) per 5 % decrease. In addition, RV end-diastolic volume index (pooled HR 1.06 [95 % CI 1.00-1.12], p = 0.049), RV end-systolic volume index (pooled HR 1.05 [95 % CI 1.01-1.09], p = 0.013) and left ventricular end-diastolic volume index (pooled HR 1.16 [95 % CI 1.00-1.34], p = 0.045) were of prognostic importance. RV and LV mass did not provide prognostic information (p = 0.852 and p = 0.983, respectively). This meta-analysis substantiates the clinical yield of specific CMR findings in the prognostication of PAH patients. Decreased RV ejection is the strongest and most well established predictor of mortality. (orig.)

  8. Cardiac magnetic resonance findings predicting mortality in patients with pulmonary arterial hypertension: a systematic review and meta-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Baggen, Vivan J.M. [AHMaZON Centre for Adult Congenital Heart Disease, University Medical Centre Utrecht, Radboud University Medical Centre Nijmegen and St. Antonius Hospital Nieuwegein, Department of Cardiology, Utrecht (Netherlands); Erasmus Medical Centre, Department of Cardiology, Rotterdam (Netherlands); Leiner, Tim; Habets, Jesse [University Medical Centre Utrecht, Department of Radiology, Utrecht (Netherlands); Post, Marco C.; Dijk, Arie P. van; Sieswerda, Gertjan T. [AHMaZON Centre for Adult Congenital Heart Disease, University Medical Centre Utrecht, Radboud University Medical Centre Nijmegen and St. Antonius Hospital Nieuwegein, Department of Cardiology, Utrecht (Netherlands); Roos-Hesselink, Jolien W. [Erasmus Medical Centre, Department of Cardiology, Rotterdam (Netherlands); Boersma, Eric [Erasmus Medical Centre, Department of Cardiology, Rotterdam (Netherlands); Erasmus Medical Centre, Department of Clinical Epidemiology, Rotterdam (Netherlands)

    2016-11-15

    To provide a comprehensive overview of all reported cardiac magnetic resonance (CMR) findings that predict clinical deterioration in pulmonary arterial hypertension (PAH). MEDLINE and EMBASE electronic databases were systematically searched for longitudinal studies published by April 2015 that reported associations between CMR findings and adverse clinical outcome in PAH. Studies were appraised using previously developed criteria for prognostic studies. Meta-analysis using random effect models was performed for CMR findings investigated by three or more studies. Eight papers (539 patients) investigating 21 different CMR findings were included. Meta-analysis showed that right ventricular (RV) ejection fraction was the strongest predictor of mortality in PAH (pooled HR 1.23 [95 % CI 1.07-1.41], p = 0.003) per 5 % decrease. In addition, RV end-diastolic volume index (pooled HR 1.06 [95 % CI 1.00-1.12], p = 0.049), RV end-systolic volume index (pooled HR 1.05 [95 % CI 1.01-1.09], p = 0.013) and left ventricular end-diastolic volume index (pooled HR 1.16 [95 % CI 1.00-1.34], p = 0.045) were of prognostic importance. RV and LV mass did not provide prognostic information (p = 0.852 and p = 0.983, respectively). This meta-analysis substantiates the clinical yield of specific CMR findings in the prognostication of PAH patients. Decreased RV ejection is the strongest and most well established predictor of mortality. (orig.)

  9. Data driven analysis of dynamic contrast-enhanced magnetic resonance imaging data in breast cancer diagnosis

    NARCIS (Netherlands)

    Twellmann, T.

    2005-01-01

    In the European Union, breast cancer is the most common type of cancer affecting women. If diagnosed in an early stage, breast cancer has an encouraging cure rate. Thus, early detection of breast cancer continues to be the key for an effective treatment. Recently, Dynamic Contrast-Enhanced Magnetic

  10. Metabolomic analysis based on 1H-nuclear magnetic resonance spectroscopy metabolic profiles in tuberculous, malignant and transudative pleural effusion

    Science.gov (United States)

    Wang, Cheng; Peng, Jingjin; Kuang, Yanling; Zhang, Jiaqiang; Dai, Luming

    2017-01-01

    Pleural effusion is a common clinical manifestation with various causes. Current diagnostic and therapeutic methods have exhibited numerous limitations. By involving the analysis of dynamic changes in low molecular weight catabolites, metabolomics has been widely applied in various types of disease and have provided platforms to distinguish many novel biomarkers. However, to the best of our knowledge, there are few studies regarding the metabolic profiling for pleural effusion. In the current study, 58 pleural effusion samples were collected, among which 20 were malignant pleural effusions, 20 were tuberculous pleural effusions and 18 were transudative pleural effusions. The small molecule metabolite spectrums were obtained by adopting 1H nuclear magnetic resonance technology, and pattern-recognition multi-variable statistical analysis was used to screen out different metabolites. One-way analysis of variance, and Student-Newman-Keuls and the Kruskal-Wallis test were adopted for statistical analysis. Over 400 metabolites were identified in the untargeted metabolomic analysis and 26 metabolites were identified as significantly different among tuberculous, malignant and transudative pleural effusions. These metabolites were predominantly involved in the metabolic pathways of amino acids metabolism, glycometabolism and lipid metabolism. Statistical analysis revealed that eight metabolites contributed to the distinction between the three groups: Tuberculous, malignant and transudative pleural effusion. In the current study, the feasibility of identifying small molecule biochemical profiles in different types of pleural effusion were investigated reveal novel biological insights into the underlying mechanisms. The results provide specific insights into the biology of tubercular, malignant and transudative pleural effusion and may offer novel strategies for the diagnosis and therapy of associated diseases, including tuberculosis, advanced lung cancer and congestive heart

  11. Diagnostic confidence analysis in the magnetic resonance imaging of ovarian and deep endometriosis: comparison with surgical results

    Energy Technology Data Exchange (ETDEWEB)

    Saba, Luca; Sulcis, Rosa; Ibba, Giannina; Piga, Mario [Azienda Ospedaliero Universitaria, Department of Radiology, Monserrato (Italy); Melis, Gian Benedetto; Guerriero, Stefano [Azienda Ospedaliero Universitaria, Department of Gynecology, Monserrato (Italy); Alcazar, Juan Luis [University of Navarra, Department of Obstetrics and Gynecology, Clinica Universidad de Navarra, Pamplona (Spain)

    2014-02-15

    To assess the diagnostic confidence of multiple readers in the magnetic resonance imaging (MRI) diagnosis of endometriosis. Sixty-five patients (mean age 33; range 19-45 years) who had undergone MRI were retrospectively evaluated. Five regions were analysed and the presence of endometriosis was scored on a five-point scale in order to assess the diagnostic confidence. Statistical analysis included receiver operating characteristic (ROC) curve analysis, the Cohen weighted test and sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, positive likelihood ratio (LR+) and negative likelihood ratio (LR-). The areas under the curve (AUC) in the detection of ovarian endometrioma were 0.942, 0.893 and 0.883 for readers 1, 2 and 3, respectively; in the uterosacral ligament (USL) AUCs were 0.907, 0.804 and 0.842; in the vaginal fornix (VF) 0.819, 0.733 and 0.69; in the anterior compartment 0.916, 0.833 and 0.873; and in the rectum/sigma/pouch of Douglas (RSD) 0.936, 0.856 and 0.834. Diagnostic confidence of the observers is different according to the region of the nodules of endometriosis and it can be challenging in the VF and for the less experience readers also in the AC and RSD. Moreover the degree of uncertain diagnosis for the less expert readers may reach up to one third of the examinations. (orig.)

  12. Texture analysis of cardiac cine magnetic resonance imaging to detect nonviable segments in patients with chronic myocardial infarction.

    Science.gov (United States)

    Larroza, Andrés; López-Lereu, María P; Monmeneu, José V; Gavara, Jose; Chorro, Francisco J; Bodí, Vicente; Moratal, David

    2018-04-01

    To investigate the ability of texture analysis to differentiate between infarcted nonviable, viable, and remote segments on cardiac cine magnetic resonance imaging (MRI). This retrospective study included 50 patients suffering chronic myocardial infarction. The data were randomly split into training (30 patients) and testing (20 patients) sets. The left ventricular myocardium was segmented according to the 17-segment model in both cine and late gadolinium enhancement (LGE) MRI. Infarcted myocardium regions were identified on LGE in short-axis views. Nonviable segments were identified as those showing LGE ≥ 50%, and viable segments those showing 0 cine images. A support vector machine (SVM) classifier was trained with different combination of texture features to obtain a model that provided optimal classification performance. The best classification on testing set was achieved with local binary patterns features using a 2D + t approach, in which the features are computed by including information of the time dimension available in cine sequences. The best overall area under the receiver operating characteristic curve (AUC) were: 0.849, sensitivity of 92% to detect nonviable segments, 72% to detect viable segments, and 85% to detect remote segments. Nonviable segments can be detected on cine MRI using texture analysis and this may be used as hypothesis for future research aiming to detect the infarcted myocardium by means of a gadolinium-free approach. © 2018 American Association of Physicists in Medicine.

  13. Functional magnetic resonance imaging in disorders of consciousness: preliminary results of an innovative analysis of brain connectivity.

    Science.gov (United States)

    De Pasquale, Francesco; Caravasso, Chiara Falletta; Péran, Patrice; Catani, Sheila; Tuovinen, Noora; Sabatini, Umberto; Formisano, Rita

    2015-01-01

    The aim of this preliminary study was to present a new approach for connectivity analysis in patients with severe acquired brain injury (ABI) that overcomes some of the difficulties created by anatomical abnormalities due to the brain injury. Using a data-driven approach, resting-state structural MRI (sMRI) and functional MRI (fMRI) data from three severe ABI patients - two with disorders of consciousness (DOC) and one who had recovered consciousness (non-DOC) - were integrated and analyzed. Parameters extracted from the distribution of the connectivity values, such as mean, standard deviation and skeweness, were considered. The distribution parameters estimated seem to provide an accurate multivariate classification of the considered cases that can be summarized as follows: connectivity in the severe ABI patients with DOC was on average lower than in the severe ABI non-DOC patient and healthy subjects. The dispersion of connectivity values of the severe ABI patients, non-DOC and DOC, was comparable, however the shape of the distribution was different in the non-DOC patient. Eventually, seed-based connectivity maps of the default mode Functional magnetic resonance imaging in disorders of consciousness: preliminary results of an innovative analysis of brain connectivity network show a pattern of increasing disruption of this network from the healthy subjects to non-DOC and DOC patients. Consistent results are obtained using an ICA-based approach..

  14. Diagnostic confidence analysis in the magnetic resonance imaging of ovarian and deep endometriosis: comparison with surgical results

    International Nuclear Information System (INIS)

    Saba, Luca; Sulcis, Rosa; Ibba, Giannina; Piga, Mario; Melis, Gian Benedetto; Guerriero, Stefano; Alcazar, Juan Luis

    2014-01-01

    To assess the diagnostic confidence of multiple readers in the magnetic resonance imaging (MRI) diagnosis of endometriosis. Sixty-five patients (mean age 33; range 19-45 years) who had undergone MRI were retrospectively evaluated. Five regions were analysed and the presence of endometriosis was scored on a five-point scale in order to assess the diagnostic confidence. Statistical analysis included receiver operating characteristic (ROC) curve analysis, the Cohen weighted test and sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, positive likelihood ratio (LR+) and negative likelihood ratio (LR-). The areas under the curve (AUC) in the detection of ovarian endometrioma were 0.942, 0.893 and 0.883 for readers 1, 2 and 3, respectively; in the uterosacral ligament (USL) AUCs were 0.907, 0.804 and 0.842; in the vaginal fornix (VF) 0.819, 0.733 and 0.69; in the anterior compartment 0.916, 0.833 and 0.873; and in the rectum/sigma/pouch of Douglas (RSD) 0.936, 0.856 and 0.834. Diagnostic confidence of the observers is different according to the region of the nodules of endometriosis and it can be challenging in the VF and for the less experience readers also in the AC and RSD. Moreover the degree of uncertain diagnosis for the less expert readers may reach up to one third of the examinations. (orig.)

  15. The gastro-esophageal reflux barrier: biophysical analysis on 3D models of anatomy from magnetic resonance imaging.

    Science.gov (United States)

    Roy, S; Fox, M R; Curcic, J; Schwizer, W; Pal, A

    2012-07-01

    The function and structure of the gastro-esophageal junction (GEJ) determine its efficacy as a reflux barrier. This study presents a novel methodology for the quantitative assessment of GEJ and proximal gastric morphology from magnetic resonance (MR) imaging. Based on this data we propose a new conceptualization of the hypothesis that a flap valve mechanism contributes to reflux protection. 3D models of the GEJ and proximal stomach were reconstructed from MR images in 12 healthy volunteers during respiration and on eating a test meal to maximum satiation. A rotating plane analysis measured the gastro-esophageal insertion angle and span of contact. An ellipsoid fit provided quantitative assessment of gastric shape and orientation relative to a fixed anatomical reference point. Position of the esophageal insertion on the 'gastric ellipse' was noted. An ellipsoid-cylinder model was designed to analyze the relationships among parameters describing the GEJ morphology. The insertion angle became more acute on expiration, but did not change with meal ingestion. In contrast the span of contact did not vary with respiration, but increased with gastric filling. Changes in gastric morphology with distension further augmented the span of gastro-esophageal contact in almost 70% of the studies. Novel MR imaging and biophysical analysis of the GEJ and proximal stomach provide a quantitative description of structures contributing to the reflux barrier. Changes in these parameters during respiration and on eating support the hypothesis that structural components of a functional 'flap valve' like mechanism contribute to reflux protection. © 2012 Blackwell Publishing Ltd.

  16. Force detection of nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Rugar, D.; Zueger, O.; Hoen, S.; Yannoni, C.S.; Vieth, H.M.; Kendrick, R.D.

    1994-01-01

    Micromechanical sensing of magnetic force was used to detect nuclear magnetic resonance with exceptional sensitivity and spatial resolution. With a 900 angstrom thick silicon nitride cantilever capable of detecting subfemtonewton forces, a single shot sensitivity of 1.6 x 10 13 protons was achieved for an ammonium nitrate sample mounted on the cantilever. A nearby millimeter-size iron particle produced a 600 tesla per meter magnetic field gradient, resulting in a spatial resolution of 2.6 micrometers in one dimension. These results suggest that magnetic force sensing is a viable approach for enhancing the sensitivity and spatial resolution of nuclear magnetic resonance microimaging

  17. Analysis of spatial diffusion of ferric ions in PVA-GTA gel dosimeters through magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Marrale, Maurizio [Dipartimento di Fisica e Chimica, Universitá di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Istituto Nazionale di Fisica Nucleare (INFN) – Gruppo V Sezione di Catania, Via Santa Sofia, 64, 95123 Catania (Italy); ATeN Center, Università di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Collura, Giorgio [Dipartimento di Fisica e Chimica, Universitá di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Istituto Nazionale di Fisica Nucleare (INFN) – Gruppo V Sezione di Catania, Via Santa Sofia, 64, 95123 Catania (Italy); Gallo, Salvatore, E-mail: salvatore.gallo05@unipa.it [Dipartimento di Fisica e Chimica, Universitá di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Istituto Nazionale di Fisica Nucleare (INFN) – Gruppo V Sezione di Catania, Via Santa Sofia, 64, 95123 Catania (Italy); Dipartimento di Fisica, Universitá di Milano, Via Giovanni Celoria 16, 20133 Milano (Italy); Nici, Stefania [Dipartimento di Fisica e Chimica, Universitá di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Tranchina, Luigi [ATeN Center, Università di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Abbate, Boris Federico [U.O.C. Fisica Sanitaria, A.R.N.A.S., Ospedale Civico Palermo, Piazza Nicola Leotta 4, 90127 Palermo (Italy); Marineo, Sandra; Caracappa, Santo [Istituto Zooprofilattico Sperimentale della Sicilia (IZS), Via Gino Marinuzzi, 3, 90129 Palermo (Italy); and others

    2017-04-01

    Highlights: • Analysis of ferric ions diffusion throughout the gel matrix in PVA-GTA samples. • Measurements with preclinical 7T MRI scanner with spatial resolution of 200 μm. • Diffusion process is much slower for PVA-GTA gels than for agarose ones. - Abstract: This work focused on the analysis of the temporal diffusion of ferric ions through PVA-GTA gel dosimeters. PVA-GTA gel samples, partly exposed with 6 MV X-rays in order to create an initial steep gradient, were mapped using magnetic resonance imaging on a 7T MRI scanner for small animals. Multiple images of the gels were acquired over several hours after irradiation and were analyzed to quantitatively extract the signal profile. The spatial resolution achieved is 200 μm and this makes this technique particularly suitable for the analysis of steep gradients of ferric ion concentration. The results obtained with PVA-GTA gels were compared with those achieved with agarose gels, which is a standard dosimetric gel formulation. The analysis showed that the diffusion process is much slower (more than five times) for PVA-GTA gels than for agarose ones. Furthermore, it is noteworthy that the diffusion coefficient value obtained through MRI analysis is significantly consistent with that obtained in separate study Marini et al. (Submitted for publication) using a totally independent method such as spectrophotometry. This is a valuable result highlighting that the good dosimetric features of this gel matrix not only can be reproduced but also can be measured through independent experimental techniques based on different physical principles.

  18. Magnetic resonance imaging in cardiovascular disease

    International Nuclear Information System (INIS)

    Eckel, C.G.; Mettler, F.A. Jr.; Wicks, J.D.; Stevens, G.F.

    1986-01-01

    How does magnetic resonance imaging (MRI) currently contribute in the evaluation of patients with suspected heart disease? What role will MRI play in the future in evaluation of cardiovascular disease? To understand better where MRI fits into the diagnostic algorithm of cardiovascular disease the authors first consider the characteristics that they would like to see in the ideal diagnostic test and then survey the available cardiac diagnostic tests to note the characteristics that limit or recommend a test. In the final analysis, the justification for expensive diagnostic tests such as MRI must be an overall improvement in survival or quality of life in those patients treated after diagnosis

  19. Magnetic resonance in hearing loss and vertigo

    Directory of Open Access Journals (Sweden)

    Manuel Ángel MARTÍN-PÉREZ

    2017-03-01

    Full Text Available Introduction and objective: Hearing loss and vertiginous syndrome represent an important part of the otorhinolaryngology clinic. The role of the radiologist plays in their workup become fundamental. Studies using magnetic resonance imaging (MRI are essential to guide or give the diagnosis in these cases. Method: After performing a retrospective analysis of 456 MRI studies of patients with these symptoms, we conducted a review of the main pathologies recorded that can cause these symptoms. Results: We classify into vascular disorders and other variants, tumor pathology, malformations and inflammatory pathology; We also describe the most relevant findings on MRI and illustrated with examples of our center.

  20. Magnetic resonance of the renal transplantation

    International Nuclear Information System (INIS)

    Cauquil, P.; Hiesse, C.; Say, C.; Verdier, J.P.; Cauquil, M.; Brunet, A.M.; Galindo, R.; Tessier, J.P.

    1989-01-01

    Renal transplantation is the treatment of choice for renal insufficiency. Progress of surgical techniques and immuno-suppression have lead to better results. One year graft survival rate are 80% in most series. In this article, the role of imaging in renal transplantation, is defined. In surgical complications (fluid collections, obstruction, vascular insufficiency) non invasive radiology and interventionnal radiologic procedures have a great impact. Despite the perspectives of duplex and magnetic resonance, sensibility and specificity are not yet specified in medical complications: rejection, acute tubular necrosis, infection, drug toxicity. Association of these lesions is frequent and complicate analysis of results. Finally, transplant biopsy is still necessary to confirm the diagnosis [fr

  1. Magnetic resonance elastometry using a single-sided permanent magnet

    International Nuclear Information System (INIS)

    Tan, Carl S; Marble, Andrew E; Ono, Yuu

    2012-01-01

    In this paper, we describe a magnetic resonance method of measuring material elasticity using a single-sided magnet with a permanent static field gradient. This method encodes sample velocity in a reciprocal space using Hahn spin-echoes with variable timing. The experimental results show a strong correlation between magnetic resonance signal attenuation and elasticity when an oscillating force is applied on the sample. This relationship in turn provides us with information about the displacement velocity experienced by the sample, which is inversely proportional to Young's modulus. The proposed method shows promise in offering a portable and cost-effective magnetic resonance elastography system. (paper)

  2. Artifacts in Magnetic Resonance Imaging

    International Nuclear Information System (INIS)

    Krupa, Katarzyna; Bekiesińska-Figatowska, Monika

    2015-01-01

    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

  3. Magnetic resonance in obstructive jaundice

    International Nuclear Information System (INIS)

    Gupta, R.K.; Jena, A.; Khushu, S.; Kakar, A.K.; Mishra, P.K.

    1989-01-01

    Twelve cases of obstructive jaundice in whom ultrasound failed to demonstrate the site and/or the cause of obstruction of the biliary tract were examined with magnetic resonance imaging (MRI), correctly diagnosing the site and cause of obstruction in 10 of 12 surgically proven cases. In one case of cholangiocarcinoma, the site of obstruction was well shown on MR but a definite cause could not be ascertained. In another patient who developed intermittent jaundice following surgery for choledochal cyst, MR demonstrated a solitary stone in the common hepatic duct. Surgical confirmation could not be achieved as the patient was lost to follow up. There were 6 cases of choledocholithiasis, 3 cases of gall bladder carcinoma and one case each of pancreatic adenocarcinoma and cholangiocarcinoma. It is believed that MRI will provide obstructive jaundice and will be able to minimize the use of percutaneous transhepatic cholangiography (PTC) and endoscopic retrograde cholangiopancreatography (ERCP) in view of its ability to perform multiplanar imaging in multiple sequences. 11 refs., figs., 1 tab

  4. Low rank magnetic resonance fingerprinting.

    Science.gov (United States)

    Mazor, Gal; Weizman, Lior; Tal, Assaf; Eldar, Yonina C

    2016-08-01

    Magnetic Resonance Fingerprinting (MRF) is a relatively new approach that provides quantitative MRI using randomized acquisition. Extraction of physical quantitative tissue values is preformed off-line, based on acquisition with varying parameters and a dictionary generated according to the Bloch equations. MRF uses hundreds of radio frequency (RF) excitation pulses for acquisition, and therefore high under-sampling ratio in the sampling domain (k-space) is required. This under-sampling causes spatial artifacts that hamper the ability to accurately estimate the quantitative tissue values. In this work, we introduce a new approach for quantitative MRI using MRF, called Low Rank MRF. We exploit the low rank property of the temporal domain, on top of the well-known sparsity of the MRF signal in the generated dictionary domain. We present an iterative scheme that consists of a gradient step followed by a low rank projection using the singular value decomposition. Experiments on real MRI data demonstrate superior results compared to conventional implementation of compressed sensing for MRF at 15% sampling ratio.

  5. Presurgical functional magnetic resonance imaging

    International Nuclear Information System (INIS)

    Stippich, C.

    2010-01-01

    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.) [de

  6. Endometrial cancer: magnetic resonance imaging.

    Science.gov (United States)

    Manfredi, R; Gui, B; Maresca, G; Fanfani, F; Bonomo, L

    2005-01-01

    Carcinoma of the endometrium is the most common invasive gynecologic malignancy of the female genital tract. Clinically, patients with endometrial carcinoma present with abnormal uterine bleeding. The role of magnetic resonance imaging (MRI) in endometrial carcinoma is disease staging and treatment planning. MRI has been shown to be the most valuable imaging mod-ality in this task, compared with endovaginal ultrasound and computed tomography, because of its intrinsic contrast resolution and multiplanar capability. MRI protocol includes axial T1-weighted images; axial, sagittal, and coronal T2-weighted images; and dynamic gadolinium-enhanced T1-weighted imaging. MR examination is usually performed in the supine position with a phased array multicoil using a four-coil configuration. Endometrial carcinoma is isointense with the normal endometrium and myometrium on noncontrast T1-weighted images and has a variable appearance on T2-weighted images demonstrating heterogeneous signal intensity. The appearance of noninvasive endometrial carcinoma on MRI is characterized by a normal or thickened endometrium, with an intact junctional zone and a sharp tumor-myometrium interface. Invasive endometrial carcinoma is characterized disruption or irregularity of the junctional zone by intermediate signal intensity mass on T2-weighted images. Invasion of the cervical stroma is diagnosed when the low signal intensity cervical stroma is disrupted by the higher signal intensity endometrial carcinoma. MRI in endometrial carcinoma performs better than other imaging modalities in disease staging and treatment planning. Further, the accuracy and the cost of MRI are equivalent to those of surgical staging.

  7. Endovascular interventional magnetic resonance imaging

    International Nuclear Information System (INIS)

    Bartels, L W; Bakker, C J G

    2003-01-01

    Minimally invasive interventional radiological procedures, such as balloon angioplasty, stent placement or coiling of aneurysms, play an increasingly important role in the treatment of patients suffering from vascular disease. The non-destructive nature of magnetic resonance imaging (MRI), its ability to combine the acquisition of high quality anatomical images and functional information, such as blood flow velocities, perfusion and diffusion, together with its inherent three dimensionality and tomographic imaging capacities, have been advocated as advantages of using the MRI technique for guidance of endovascular radiological interventions. Within this light, endovascular interventional MRI has emerged as an interesting and promising new branch of interventional radiology. In this review article, the authors will give an overview of the most important issues related to this field. In this context, we will focus on the prerequisites for endovascular interventional MRI to come to maturity. In particular, the various approaches for device tracking that were proposed will be discussed and categorized. Furthermore, dedicated MRI systems, safety and compatibility issues and promising applications that could become clinical practice in the future will be discussed. (topical review)

  8. Magnetic resonance imaging and neurolupus

    International Nuclear Information System (INIS)

    Schott, A.M.; Colson, F.; Tebib, J.; Noel, E.; Bouvier, M.

    1990-01-01

    Magnetic resonance imaging (MRI) was assessed in the management of neuropsychiatric manifestations occurring in 6 SLE patients. The MRI scans were normal in 3 cases and was associated with remission of the symptoms except for a patient who experienced a chorea at the time of the examination. Abnormal MRI scans always revealed more lesions than CT scan. 2 different patterns of abnormalities seem to correspond to 2 specific disorders. In 2 patients with clinical presentation suggesting a cortical ischemia by vascular thrombosis, both MRI scans showed areas of abnormal high signal intensities located in the subcortical white matter. In one last patient, MRI scan revealed multiple focal areas of high signal intensities (on T 1 weighter scans) disseminated not only in the deep white matter but also in the gray one. These lesions could be depend upon demyelinisation which may occur by a local vascular process. This serie confirms the interest of MRI in the management of SLE brain involvement as well as it points out some problem of interpretation. This suggest further comparative studies especially at the real onset and during the course of neuro-psychiatric manifestations. At last, the coronal sections may be more informative for the diagnosis and patholophysiology than the horizontal ones [fr

  9. Magnetic resonance in multiple sclerosis

    International Nuclear Information System (INIS)

    Scotti, G.; Caputo, D.; Cazzullo, C.L.

    1986-01-01

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

  10. Myositis ossificans: magnetic resonance images

    International Nuclear Information System (INIS)

    Dosda, R.; Marti-Bonmati, L.; Concepcion, L.; Galant, J.

    1999-01-01

    Myositis ossificans is characterized by a benign, self-limiting, ossifying mass of the white tissue. In the present report, we describe the magnetic resonance (MR) images in three cases of myositis ossificans in pediatric patients, correlating the MR findings with those obtained with other radiological studies. The lesions were detected in three patients, two boys and one girl, ranging in age between 10 and 14 years. The nature of the lesion was confirmed histologically in all three cases. The MR images were obtained using superconductive units at 0.5 Teslas, with T1 and T2-weighted spin-echo and STIR sequences. In two patients, gadolinium-enhanced T1-weighted images were also obtained. As in any process of maturation, the proliferation/maturation ratio depends on the moment in the course of the lesion, which affects its MR features,. In acute phases, the soft tissue mass with an intraosseous, perilesional adematous reaction predominates, while annular calcification and lesser edema are characteristic of subacute episode. Myositis ossificans is very rare in children. The inflammatory response may present a radiological pattern difficult to distinguish from that of aggressive tumor or infection, especially in the acute phase. (Author) 7 refs

  11. Three-dimensional regional strain analysis in porcine myocardial infarction: a 3T magnetic resonance tagging study

    Directory of Open Access Journals (Sweden)

    Soleimanifard Sahar

    2012-12-01

    Full Text Available Abstract Background Previous studies of mechanical strain anomalies in myocardial infarction (MI have been largely limited to analysis of one-dimensional (1D and two-dimensional (2D strain parameters. Advances in cardiovascular magnetic resonance (CMR methods now permit a complete three-dimensional (3D interrogation of myocardial regional strain. The aim of this study was to investigate the incremental value of CMR-based 3D strain and to test the hypothesis that 3D strain is superior to 1D or 2D strain analysis in the assessment of viability using a porcine model of infarction. Methods Infarction was induced surgically in 20 farm pigs. Cine, late gadolinium enhancement, and CMR tagging images were acquired at 11 days before (baseline, and 11 days (early and 1 month (late after induction of infarct. Harmonic phase analysis was performed to measure circumferential, longitudinal, and radial strains in myocardial segments, which were defined based on the transmurality of delayed enhancement. Univariate, bivariate, and multivariate logistic regression models of strain parameters were created and analyzed to compare the overall diagnostic accuracy of 3D strain analysis with 1D and 2D analyses in identifying the infarct and its adjacent regions from healthy myocardium. Results 3D strain differed significantly in infarct, adjacent, and remote segments (p  Conclusions Cumulative 3D strain information accurately identifies infarcts and their neighboring regions from healthy myocardium. The 3D interrogation of myocardial contractility provides incremental diagnostic accuracy in delineating the dysfunctional and nonviable myocardium in comparison with 1D or 2D quantification of strain. The infarct neighboring regions are the major beneficiaries of the 3D assessment of regional strain.

  12. Cardiovascular magnetic resonance in congenital heart disease

    International Nuclear Information System (INIS)

    Cazacu, A.; Ciubotaru, A.

    2010-01-01

    The increasing prevalence of congenital heart disease can be attributed to major improvements in diagnosis and treatment. Cardiovascular magnetic resonance imaging plays an important role in the clinical management strategy of patients with congenital heart disease. The development of new cardiovascular magnetic resonance (CMR) techniques allows comprehensive assessment of complex cardiac anatomy and function and provides information about the long-term residual post-operative lesions and complications of surgery. It overcomes many of the limitations of echocardiography and cardiac catheterization. This review evaluates the role of cardiovascular magnetic resonance imaging modality in the management of subject with congenital heart disease (CHD). (authors)

  13. NMR magnetic field controller for pulsed nuclear magnetic resonance experiments

    International Nuclear Information System (INIS)

    Scheler, G.; Anacker, M.

    1975-01-01

    A nuclear magnetic resonance controller for magnetic fields, which can also be used for pulsed NMR investigations, is described. A longtime stability of 10 -7 is achieved. The control signal is generated by a modified time sharing circuit with resonance at the first side band of the 2 H signal. An exact calibration of the magnetic field is achieved by the variation of the H 1 - or of the time-sharing frequency. (author)

  14. Analysis and optimization of coupled windings in magnetic resonant wireless power transfer systems with orthogonal experiment method

    DEFF Research Database (Denmark)

    Yudi, Xiao; Xingkui, Mao; Mao, Lin

    2017-01-01

    The coupled magnetic resonant unit (CMRU) has great effect on the transmitting power capability and efficiency of magnetic resonant wireless power transfer system. The key objective i.e. the efficiency coefficient kQ is introduced in the design of CMRU or the coupled windings based on the mutual...... inductance model. Then the design method with orthogonal experiments and finite element method simulation is proposed to maximize the kQ due to low precise analytical model of AC resistance and inductance for PCB windings at high- frequency. The method can reduce the design iterations and thereby can get...... more optimal design results. The experiments verified the design objective of kQ as well as the design method effectively. In the optimal PCB windings prototype at operating frequency of 4 MHz, the kQ and the maximum efficiency are increased by about 12% and 4% respectively....

  15. Analysis and optimisation of coupled winding in magnetic resonant wireless power transfer systems with orthogonal experiment results

    DEFF Research Database (Denmark)

    Yudi, Xiao; Xingkui, Mao; Mao, Lin

    2017-01-01

    The coupled magnetic resonant unit (CMRU) has great effect on the transmitting power capability and efficiency of magnetic resonant wireless power transfer system. The key objective i.e. the efficiency coefficient kQ is introduced in the design of CMRU or the coupled windings based on the mutual...... inductance model. Then the design method with orthogonal experiments and finite element method simulation is proposed to maximize the kQ due to low precise analytical model of AC resistance and inductance for PCB windings at high- frequency. The method can reduce the design iterations and thereby can get...... more optimal design results. The experiments verified the design objective of kQ as well as the design method effectively. In the optimal PCB windings prototype at operating frequency of 4 MHz, the kQ and the maximum efficiency are increased by about 12% and 4% respectively....

  16. Non-invasive analysis of bovine embryo metabolites during in vitro embryo culture using nuclear magnetic resonance

    Directory of Open Access Journals (Sweden)

    Marcello Rubessa

    2016-12-01

    Full Text Available The ability to identify embryos that have the highest developmental potential from a cohort would significantly increase the chances of achieving pregnancy. Metabolic analysis is a well-established analytical approach in biological systems. Starting from this idea, we chose to use high-resolution nuclear magnetic resonance (1H-NMR spectroscopy. The aim of this study was to determine if it is possible to select viable embryos after 48 h of culture using metabolic activity as the parameter. We evaluated embryo metabolism after the first 48 h of culture and compared the activity of cleaved embryos that became blastocysts to cleaved embryos that did not develop to blastocysts, and in vitro fertilized (IVF blastocysts and parthenogenetic-activated (PA blastocysts. Our results show that citrate, pyruvate, myo-inositol and lysine have great impact on predicting embryo development. When we compared IVF and PA blastocysts, we found that acetate and phenylalanine concentrations are excellent parameters for evaluating blastocyst quality. Combining all these results, we were able to create a formula that predicts zygote development after 2 days of culture. In conclusion, we found that it is possible predict the future development of in vitro produced bovine embryos after only 2 days of culture using 1H-NMR.

  17. Semi-automated vectorial analysis of anorectal motion by magnetic resonance defecography in healthy subjects and fecal incontinence.

    Science.gov (United States)

    Noelting, J; Bharucha, A E; Lake, D S; Manduca, A; Fletcher, J G; Riederer, S J; Joseph Melton, L; Zinsmeister, A R

    2012-10-01

    Inter-observer variability limits the reproducibility of pelvic floor motion measured by magnetic resonance imaging (MRI). Our aim was to develop a semi-automated program measuring pelvic floor motion in a reproducible and refined manner. Pelvic floor anatomy and motion during voluntary contraction (squeeze) and rectal evacuation were assessed by MRI in 64 women with fecal incontinence (FI) and 64 age-matched controls. A radiologist measured anorectal angles and anorectal junction motion. A semi-automated program did the same and also dissected anorectal motion into perpendicular vectors representing the puborectalis and other pelvic floor muscles, assessed the pubococcygeal angle, and evaluated pelvic rotation. Manual and semi-automated measurements of anorectal junction motion (r = 0.70; P controls. This semi-automated program provides a reproducible, efficient, and refined analysis of pelvic floor motion by MRI. Puborectalis injury is independently associated with impaired motion of puborectalis, not other pelvic floor muscles in controls and women with FI. © 2012 Blackwell Publishing Ltd.

  18. 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.

  19. Classification of Ilex species based on metabolomic fingerprinting using nuclear magnetic resonance and multivariate data analysis.

    Science.gov (United States)

    Choi, Young Hae; Sertic, Sarah; Kim, Hye Kyong; Wilson, Erica G; Michopoulos, Filippos; Lefeber, Alfons W M; Erkelens, Cornelis; Prat Kricun, Sergio D; Verpoorte, Robert

    2005-02-23

    The metabolomic analysis of 11 Ilex species, I. argentina, I. brasiliensis, I. brevicuspis, I. dumosavar. dumosa, I. dumosa var. guaranina, I. integerrima, I. microdonta, I. paraguariensis var. paraguariensis, I. pseudobuxus, I. taubertiana, and I. theezans, was carried out by NMR spectroscopy and multivariate data analysis. The analysis using principal component analysis and classification of the (1)H NMR spectra showed a clear discrimination of those samples based on the metabolites present in the organic and aqueous fractions. The major metabolites that contribute to the discrimination are arbutin, caffeine, phenylpropanoids, and theobromine. Among those metabolites, arbutin, which has not been reported yet as a constituent of Ilex species, was found to be a biomarker for I. argentina,I. brasiliensis, I. brevicuspis, I. integerrima, I. microdonta, I. pseudobuxus, I. taubertiana, and I. theezans. This reliable method based on the determination of a large number of metabolites makes the chemotaxonomical analysis of Ilex species possible.

  20. Magnetic resonance of native defects of spin-Peierls magnetics CuGeO3

    International Nuclear Information System (INIS)

    Smirnov, A.I.; Glazkov, V.N.; Leonyuk, L.I.; Vetkin, A.G.; Eremina, R.M.

    1998-01-01

    Magnetic resonance within 9-75 GHz frequency range and 1.2-25 K temperature range was studied in pure monocrystalline spin-Peierls CuGwO 3 . Splitting of the magnetic resonance line is observed within temperature range below 5 K. Analysis of magnetic resonance spectra at various directions of magnetic field and under various temperatures enables to set off EPR-signals of spin-Peierls phase defects with S=1/2 and defects with S=1 from these components; g-factor corresponding to these EPR signals is similar one and close to values typical for Cu 2+ ion [ru

  1. Soil organic matter composition from correlated thermal analysis and nuclear magnetic resonance data in Australian national inventory of agricultural soils

    Science.gov (United States)

    Moore, T. S.; Sanderman, J.; Baldock, J.; Plante, A. F.

    2016-12-01

    National-scale inventories typically include soil organic carbon (SOC) content, but not chemical composition or biogeochemical stability. Australia's Soil Carbon Research Programme (SCaRP) represents a national inventory of SOC content and composition in agricultural systems. The program used physical fractionation followed by 13C nuclear magnetic resonance (NMR) spectroscopy. While these techniques are highly effective, they are typically too expensive and time consuming for use in large-scale SOC monitoring. We seek to understand if analytical thermal analysis is a viable alternative. Coupled differential scanning calorimetry (DSC) and evolved gas analysis (CO2- and H2O-EGA) yields valuable data on SOC composition and stability via ramped combustion. The technique requires little training to use, and does not require fractionation or other sample pre-treatment. We analyzed 300 agricultural samples collected by SCaRP, divided into four fractions: whole soil, coarse particulates (POM), untreated mineral associated (HUM), and hydrofluoric acid (HF)-treated HUM. All samples were analyzed by DSC-EGA, but only the POM and HF-HUM fractions were analyzed by NMR. Multivariate statistical analyses were used to explore natural clustering in SOC composition and stability based on DSC-EGA data. A partial least-squares regression (PLSR) model was used to explore correlations among the NMR and DSC-EGA data. Correlations demonstrated regions of combustion attributable to specific functional groups, which may relate to SOC stability. We are increasingly challenged with developing an efficient technique to assess SOC composition and stability at large spatial and temporal scales. Correlations between NMR and DSC-EGA may demonstrate the viability of using thermal analysis in lieu of more demanding methods in future large-scale surveys, and may provide data that goes beyond chemical composition to better approach quantification of biogeochemical stability.

  2. Diagnostic value of 3D time-of-flight magnetic resonance angiography for detecting intracranial aneurysm: a meta-analysis.

    Science.gov (United States)

    HaiFeng, Liu; YongSheng, Xu; YangQin, Xun; Yu, Dou; ShuaiWen, Wang; XingRu, Lu; JunQiang, Lei

    2017-11-01

    This meta-analysis is to comprehensively evaluate the diagnostic performance of three-dimensional time-of-flight magnetic resonance angiography (3D-TOF-MRA) for detecting intracranial aneurysm (IA). PubMed, Embase, Web of Science, and the Cochrane library were systematically searched for retrieving eligible studies. Study inclusion, data extraction, and risk of bias assessment were performed by two researchers independently. Pooled sensitivity (SEN), specificity (SPE), positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and area under the curve (AUC) were calculated to assess the diagnostic value. In addition, heterogeneity and subgroup analysis were carried out. In total, 18 studies comprising 3463 patients were selected. The results of 3D-TOF-MRA for diagnosing IA were SEN 0.89 (95% CI 0.82-0.94), SPE 0.94 (0.86-0.97), PLR 13.79 (5.92-32.12), NLR 0.11 (0.07-0.19), DOR 121.90 (38.81-382.94), and AUC 0.96 (0.94-0.98), respectively. In the subgroup analysis, studies without subarachnoid hemorrhage (SAH) tend to perform statistical significantly better (P 3D-TOF-MRA had better SEN in aneurysms > 3 mm than the aneurysms ≤ 3 mm in diameter: 0.89 (0.87-0.92) vs. 0.78 (0.71-0.84) with P 3D-TOF-MRA has an excellent diagnostic performance for the overall assessment of IA and may serve as an alternative for further patient management with IA.

  3. 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

  4. Pocket atlas of cranial magnetic resonance imaging

    International Nuclear Information System (INIS)

    Haughton, V.M.; Daniels, D.L.

    1986-01-01

    This atlas illustrates normal cerebral anatomy in magnetic resonance images. From their studies in cerebral anatomy utilizing cryomicrotome and other techniques, the authors selected more than 100 high-resolution images that represent the most clinically useful scans

  5. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... Disorders Video: The Basketball Game: An MRI Story Radiology and You Sponsored by Image/Video Gallery Your ... Explains Magnetic Resonance Angiography (MRA) Transcript Welcome to Radiology Info dot org Hello, I’m Dr. Elliot ...

  6. Fifty years of nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Martinez Valderrama, Juan Crisostomo

    1997-01-01

    Short information about the main developments of nuclear magnetic resonance during their fifty existence years is presented. Beside two examples of application (HETCOR and INADEQUATE) to the structural determination of organic compounds are described

  7. Principles of nuclear magnetic resonance imaging

    International Nuclear Information System (INIS)

    Pykett, I.L.; Newhouse, J.H.; Buonanno, F.S.; Brady, T.J.; Goldman, M.R.; Kistler, J.P.; Pohost, G.M.

    1982-01-01

    The physical principles which underlie the phenomenon of nuclear magnetic resonance (NMR) are presented in this primer. The major scanning methods are reviewed, and the principles of technique are discussed. A glossary of NMR terms is included

  8. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... with you about magnetic resonance angiography, or as it’s commonly known, MRA. MRA is a noninvasive test ... of the major blood vessels throughout your body. It may be performed with or without contrast material ...

  9. The role of magnetic resonance cholangiopancreatography and ...

    African Journals Online (AJOL)

    ) is accepted as the gold standard, there is a place for magnetic resonance cholangiopancreatography (MRCP) and diffusion-weighted imaging (DWI) in the diagnosis of obstructive biliary disorders. Aim: To compare the findings of MRCP with ...

  10. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... An MRI Story Radiology and You Sponsored by Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography ( ... posted: How to Obtain and Share Your Medical Images Movement Disorders Video: The Basketball Game: An MRI ...

  11. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... mild sedative prior to the examination. For more information about Magnetic Resonance Angiography of MRA or any ... Inc. (RSNA). To help ensure current and accurate information, we do not permit copying but encourage linking ...

  12. Chronic liver disease: evaluation by magnetic resonance

    International Nuclear Information System (INIS)

    Stark, D.D.; Goldberg, H.I.; Moss, A.A.; Bass, N.M.

    1984-01-01

    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. Nuclear Magnetic Resonance Trackbed Moisture Sensor System

    Science.gov (United States)

    2018-02-01

    In this initial phase, conducted from March 2015 through December 2016, Vista Clara and its subcontractor Zetica Rail successfully developed and tested a man-portable, non-invasive spot-check nuclear magnetic resonance (NMR) moisture sensor that dire...

  14. 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....

  15. Nuclear magnetic resonance spectroscopy and imaging

    International Nuclear Information System (INIS)

    Jiang Weiping; Wang Qi; Zhou Xin

    2013-01-01

    This paper briefly introduces the basic principle of nuclear magnetic resonance (NMR). Protein's structures and functions and dynamics studied by liquid NMR are elaborated; methods for enhancing the resolution of solid state NMR and its applications are discussed; the principle of magnetic resonance imaging (MRI) is interpreted, and applications in different aspects are reviewed. Finally, the progress of NMR is commented. (authors)

  16. Concepts and indications of abdominal magnetic resonance

    International Nuclear Information System (INIS)

    Murillo Viera, Wendy

    2012-01-01

    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 [es

  17. Magnetic resonance imaging of muscle tears

    International Nuclear Information System (INIS)

    De Smet, A.A.; Fisher, D.R.; Heiner, J.P.; Keene, J.S.

    1990-01-01

    Magnetic resonance scans were obtained on 17 patients with acute, subacute, or chronic muscle tears. These patients presented with complaints of persistent pain or a palpable mass. Magnetic resonance findings were characterized according to alterations in muscle shape and the presence of abnormal high signal within the injured muscle. These areas of high signal were noted on both T1-weighted and T2-weighted scans and were presumed to represent areas of intramuscular hemorrhage. (orig.)

  18. Clinical magnetic resonance: imaging and spectroscopy

    International Nuclear Information System (INIS)

    Andrew, E.R.; Bydder, Graeme; Griffiths, John; Iles, Richard; Styles, Peter

    1990-01-01

    This book begins with a readable, comprehensive but non-mathematical introduction to the basic underlying principles of magnetic resonance. Further chapters include information on the theory and principles of MRI and MRS, the interpretation of MR images, the clinical applications and scope of MRI and MRS, practical aspects of spectroscopy and magnetic resonance, and also the practical problems associated with the siting, safety and operation of large MRI and MRS equipment. (author)

  19. Analytical applications of a recycled flow nuclear magnetic resonance system: quantitative analysis of slowly relaxing nuclei

    International Nuclear Information System (INIS)

    Laude, D.A. Jr.; Lee, R.W.K.; Wilkins, C.L.

    1985-01-01

    The utility of a recycled flow system for the efficient quantitative analysis of NMR spectra is demonstrated. Requisite conditions are first established for the quantitative flow experiment and then applied to a variety of compounds. An application of the technique to determination of the average polymer chain length for a silicone polymer by quantitative flow 29 Si NMR is also presented. 10 references, 4 figures, 3 tables

  20. Effect of phase-encoding direction on group analysis of resting-state functional magnetic resonance imaging.

    Science.gov (United States)

    Mori, Yasuo; Miyata, Jun; Isobe, Masanori; Son, Shuraku; Yoshihara, Yujiro; Aso, Toshihiko; Kouchiyama, Takanori; Murai, Toshiya; Takahashi, Hidehiko

    2018-05-17

    Echo-planar imaging is a common technique used in functional magnetic resonance imaging (fMRI), however it suffers from image distortion and signal loss because of large susceptibility effects that are related to the phase-encoding direction of the scan. Despite this relationship, the majority of neuroimaging studies have not considered the influence of phase-encoding direction. Here, we aimed to clarify how phase-encoding direction can affect the outcome of an fMRI connectivity study of schizophrenia. Resting-state fMRI using anterior to posterior (A-P) and posterior to anterior (P-A) directions was used to examine 25 patients with schizophrenia (SC) and 37 matched healthy controls (HC). We conducted a functional connectivity analysis using independent component analysis and performed three group comparisons: A-P vs. P-A (all participants), SC vs. HC for the A-P and P-A datasets, and the interaction between phase-encoding direction and participant group. The estimated functional connectivity differed between the two phase-encoding directions in areas that were more extensive than those where signal loss has been reported. Although functional connectivity in the SC group was lower than that in the HC group for both directions, the A-P and P-A conditions did not exhibit the same specific pattern of differences. Further, we observed an interaction between participant group and the phase-encoding direction in the left temporo-parietal junction and left fusiform gyrus. Phase-encoding direction can influence the results of functional connectivity studies. Thus, appropriate selection and documentation of phase-encoding direction will be important in future resting-state fMRI studies. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  1. A Tool for Classifying Individuals with Chronic Back Pain: Using Multivariate Pattern Analysis with Functional Magnetic Resonance Imaging Data

    Science.gov (United States)

    Callan, Daniel; Mills, Lloyd; Nott, Connie; England, Robert; England, Shaun

    2014-01-01

    Chronic pain is one of the most prevalent health problems in the world today, yet neurological markers, critical to diagnosis of chronic pain, are still largely unknown. The ability to objectively identify individuals with chronic pain using functional magnetic resonance imaging (fMRI) data is important for the advancement of diagnosis, treatment, and theoretical knowledge of brain processes associated with chronic pain. The purpose of our research is to investigate specific neurological markers that could be used to diagnose individuals experiencing chronic pain by using multivariate pattern analysis with fMRI data. We hypothesize that individuals with chronic pain have different patterns of brain activity in response to induced pain. This pattern can be used to classify the presence or absence of chronic pain. The fMRI experiment consisted of alternating 14 seconds of painful electric stimulation (applied to the lower back) with 14 seconds of rest. We analyzed contrast fMRI images in stimulation versus rest in pain-related brain regions to distinguish between the groups of participants: 1) chronic pain and 2) normal controls. We employed supervised machine learning techniques, specifically sparse logistic regression, to train a classifier based on these contrast images using a leave-one-out cross-validation procedure. We correctly classified 92.3% of the chronic pain group (N = 13) and 92.3% of the normal control group (N = 13) by recognizing multivariate patterns of activity in the somatosensory and inferior parietal cortex. This technique demonstrates that differences in the pattern of brain activity to induced pain can be used as a neurological marker to distinguish between individuals with and without chronic pain. Medical, legal and business professionals have recognized the importance of this research topic and of developing objective measures of chronic pain. This method of data analysis was very successful in correctly classifying each of the two

  2. Evaluation of Liver Fibrosis Using Texture Analysis on Combined-Contrast-Enhanced Magnetic Resonance Images at 3.0T

    Directory of Open Access Journals (Sweden)

    Takeshi Yokoo

    2015-01-01

    Full Text Available Purpose. To noninvasively assess liver fibrosis using combined-contrast-enhanced (CCE magnetic resonance imaging (MRI and texture analysis. Materials and Methods. In this IRB-approved, HIPAA-compliant prospective study, 46 adults with newly diagnosed HCV infection and recent liver biopsy underwent CCE liver MRI following intravenous administration of superparamagnetic iron oxides (ferumoxides and gadolinium DTPA (gadopentetate dimeglumine. The image texture of the liver was quantified in regions-of-interest by calculating 165 texture features. Liver biopsy specimens were stained with Masson trichrome and assessed qualitatively (METAVIR fibrosis score and quantitatively (% collagen stained area. Using L1 regularization path algorithm, two texture-based multivariate linear models were constructed, one for quantitative and the other for quantitative histology prediction. The prediction performance of each model was assessed using receiver operating characteristics (ROC and correlation analyses. Results. The texture-based predicted fibrosis score significantly correlated with qualitative (r=0.698, P<0.001 and quantitative (r=0.757, P<0.001 histology. The prediction model for qualitative histology had 0.814–0.976 areas under the curve (AUC, 0.659–1.000 sensitivity, 0.778–0.930 specificity, and 0.674–0.935 accuracy, depending on the binary classification threshold. The prediction model for quantitative histology had 0.742–0.950 AUC, 0.688–1.000 sensitivity, 0.679–0.857 specificity, and 0.696–0.848 accuracy, depending on the binary classification threshold. Conclusion. CCE MRI and texture analysis may permit noninvasive assessment of liver fibrosis.

  3. A tool for classifying individuals with chronic back pain: using multivariate pattern analysis with functional magnetic resonance imaging data.

    Directory of Open Access Journals (Sweden)

    Daniel Callan

    Full Text Available Chronic pain is one of the most prevalent health problems in the world today, yet neurological markers, critical to diagnosis of chronic pain, are still largely unknown. The ability to objectively identify individuals with chronic pain using functional magnetic resonance imaging (fMRI data is important for the advancement of diagnosis, treatment, and theoretical knowledge of brain processes associated with chronic pain. The purpose of our research is to investigate specific neurological markers that could be used to diagnose individuals experiencing chronic pain by using multivariate pattern analysis with fMRI data. We hypothesize that individuals with chronic pain have different patterns of brain activity in response to induced pain. This pattern can be used to classify the presence or absence of chronic pain. The fMRI experiment consisted of alternating 14 seconds of painful electric stimulation (applied to the lower back with 14 seconds of rest. We analyzed contrast fMRI images in stimulation versus rest in pain-related brain regions to distinguish between the groups of participants: 1 chronic pain and 2 normal controls. We employed supervised machine learning techniques, specifically sparse logistic regression, to train a classifier based on these contrast images using a leave-one-out cross-validation procedure. We correctly classified 92.3% of the chronic pain group (N = 13 and 92.3% of the normal control group (N = 13 by recognizing multivariate patterns of activity in the somatosensory and inferior parietal cortex. This technique demonstrates that differences in the pattern of brain activity to induced pain can be used as a neurological marker to distinguish between individuals with and without chronic pain. Medical, legal and business professionals have recognized the importance of this research topic and of developing objective measures of chronic pain. This method of data analysis was very successful in correctly classifying

  4. Nuclear magnetic resonance method and apparatus

    International Nuclear Information System (INIS)

    Burl, M.; Young, I.R.

    1984-01-01

    A method and apparatus for determining the rate of flow of a liquid in a selected region of a body by nuclear magnetic resonance techniques are described. The method includes a sequence of applying a first magnetic pulse effective to excite nuclear magnetic resonance of a chosen nucleus within the liquid preferentially in a slice of the body which includes the selected region. A period of time (tsub(D)) is waited and then a second magnetic pulse is applied which is effective to excite nuclear magnetic resonance of the nuclei preferentially in the slice, and the free induction decay signal is measured. The whole sequence is repeated for different values of the period of time (tsub(D)). The variation in the value of the measured signal with tsub(D) is then related to the rate of flow of the liquid through the slice. (author)

  5. Claustrophobia in magnetic resonance imaging: A systematic review and meta-analysis

    International Nuclear Information System (INIS)

    Munn, Zachary; Moola, Sandeep; Lisy, Karolina; Riitano, Dagmara; Murphy, Fred

    2015-01-01

    Purpose: Anxiety and claustrophobia are common during MRI scanning. It has been estimated that 2 million scans worldwide cannot be performed annually either due to premature scan termination or refusal due to claustrophobia. The actual prevalence of claustrophobic reactions (defined here as scan terminations or refusals) reported in published studies varies significantly. Materials and methods: A systematic search was performed to identify literature on this topic. Studies were included if they assessed adults undergoing MRI and reported on claustrophobic reactions. Data on the proportion of patients who suffered a claustrophobic reaction was extracted and combined in a meta-analysis where possible. Following the search, 18 studies were retrieved that met the inclusion criteria. Results: There was significant clinical and statistical heterogeneity across the included studies, and data was only included in meta-analysis where there were comparable populations and scan. The pooled proportion for scan terminations due to claustrophobia equalled 1.18% (95% CI 0.79–1.65). Conclusion: The results of this review show that claustrophobia is an issue when undergoing MRI, with approximately 1 out of 100 or 12 out of 1000 people scanned experiencing a claustrophobic reaction requiring premature termination of the scan. Health professionals working in MRI should be prepared to encounter claustrophobic patients. - Highlights: • We reviewed all the published literature reporting on claustrophobic events during MRI. • Meta-analysis of these results shows that 1.2 people out of 100 have a claustrophobic event. • Health professionals working in MRI need to be prepared to encounter claustrophobic patients

  6. An open source software for analysis of dynamic contrast enhanced magnetic resonance images: UMMPerfusion revisited.

    Science.gov (United States)

    Zöllner, Frank G; Daab, Markus; Sourbron, Steven P; Schad, Lothar R; Schoenberg, Stefan O; Weisser, Gerald

    2016-01-14

    Perfusion imaging has become an important image based tool to derive the physiological information in various applications, like tumor diagnostics and therapy, stroke, (cardio-) vascular diseases, or functional assessment of organs. However, even after 20 years of intense research in this field, perfusion imaging still remains a research tool without a broad clinical usage. One problem is the lack of standardization in technical aspects which have to be considered for successful quantitative evaluation; the second problem is a lack of tools that allow a direct integration into the diagnostic workflow in radiology. Five compartment models, namely, a one compartment model (1CP), a two compartment exchange (2CXM), a two compartment uptake model (2CUM), a two compartment filtration model (2FM) and eventually the extended Toft's model (ETM) were implemented as plugin for the DICOM workstation OsiriX. Moreover, the plugin has a clean graphical user interface and provides means for quality management during the perfusion data analysis. Based on reference test data, the implementation was validated against a reference implementation. No differences were found in the calculated parameters. We developed open source software to analyse DCE-MRI perfusion data. The software is designed as plugin for the DICOM Workstation OsiriX. It features a clean GUI and provides a simple workflow for data analysis while it could also be seen as a toolbox providing an implementation of several recent compartment models to be applied in research tasks. Integration into the infrastructure of a radiology department is given via OsiriX. Results can be saved automatically and reports generated automatically during data analysis ensure certain quality control.

  7. An open source software for analysis of dynamic contrast enhanced magnetic resonance images: UMMPerfusion revisited

    International Nuclear Information System (INIS)

    Zöllner, Frank G.; Daab, Markus; Sourbron, Steven P.; Schad, Lothar R.; Schoenberg, Stefan O.; Weisser, Gerald

    2016-01-01

    Perfusion imaging has become an important image based tool to derive the physiological information in various applications, like tumor diagnostics and therapy, stroke, (cardio-) vascular diseases, or functional assessment of organs. However, even after 20 years of intense research in this field, perfusion imaging still remains a research tool without a broad clinical usage. One problem is the lack of standardization in technical aspects which have to be considered for successful quantitative evaluation; the second problem is a lack of tools that allow a direct integration into the diagnostic workflow in radiology. Five compartment models, namely, a one compartment model (1CP), a two compartment exchange (2CXM), a two compartment uptake model (2CUM), a two compartment filtration model (2FM) and eventually the extended Toft’s model (ETM) were implemented as plugin for the DICOM workstation OsiriX. Moreover, the plugin has a clean graphical user interface and provides means for quality management during the perfusion data analysis. Based on reference test data, the implementation was validated against a reference implementation. No differences were found in the calculated parameters. We developed open source software to analyse DCE-MRI perfusion data. The software is designed as plugin for the DICOM Workstation OsiriX. It features a clean GUI and provides a simple workflow for data analysis while it could also be seen as a toolbox providing an implementation of several recent compartment models to be applied in research tasks. Integration into the infrastructure of a radiology department is given via OsiriX. Results can be saved automatically and reports generated automatically during data analysis ensure certain quality control

  8. Three-dimensional morphometric analysis of the coracohumeral distance using magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Taku Hatta

    2017-03-01

    Full Text Available There have been no studies investigating three-dimensional (3D alteration of the coracohumeral distance (CHD associated with shoulder motion. The aim of this study was to investigate the change of 3D-CHD with the arm in flexion/internal rotation and horizontal adduction. Six intact shoulders of four healthy volunteers were obtained for this study. MRI was taken in four arm positions: with the arm in internal rotation at 0°, 45°, and 90° of flexion, and 90° of flexion with maximum horizontal adduction. Using a motion analysis system, 3D models of the coracoid process and proximal humerus were created from MRI data. The CHD among the four positions were compared, and the closest part of coracoid process to the proximal humerus was also assessed. 3D-CHD significantly decreased with the arm in 90° of flexion and in 90° of flexion with horizontal adduction comparing with that in 0° flexion (P<0.05. In all subjects, lateral part of the coracoid process was the closest to the proximal humerus in these positions. In vivo quasi-static motion analysis revealed that the 3D-CHD was narrower in the arm position of flexion with horizontal abduction than that in 0° flexion. The lateral part on the coracoid process should be considered to be closest to the proximal humerus during the motion.

  9. Comparing the magnetic resonant coupling radiofrequency stimulation to the traditional approaches: Ex-vivo tissue voltage measurement and electromagnetic simulation analysis

    Science.gov (United States)

    Yeung, Sai Ho; Pradhan, Raunaq; Feng, Xiaohua; Zheng, Yuanjin

    2015-09-01

    Recently, the design concept of magnetic resonant coupling has been adapted to electromagnetic therapy applications such as non-invasive radiofrequency (RF) stimulation. This technique can significantly increase the electric field radiated from the magnetic coil at the stimulation target, and hence enhancing the current flowing through the nerve, thus enabling stimulation. In this paper, the developed magnetic resonant coupling (MRC) stimulation, magnetic stimulation (MS) and transcutaneous electrical nerve stimulation (TENS) are compared. The differences between the MRC RF stimulation and other techniques are presented in terms of the operating mechanism, ex-vivo tissue voltage measurement and electromagnetic simulation analysis. The ev-vivo tissue voltage measurement experiment is performed on the compared devices based on measuring the voltage induced by electromagnetic induction at the tissue. The focusing effect, E field and voltage induced across the tissue, and the attenuation due to the increase of separation between the coil and the target are analyzed. The electromagnetic stimulation will also be performed to obtain the electric field and magnetic field distribution around the biological medium. The electric field intensity is proportional to the induced current and the magnetic field is corresponding to the electromagnetic induction across the biological medium. The comparison between the MRC RF stimulator and the MS and TENS devices revealed that the MRC RF stimulator has several advantages over the others for the applications of inducing current in the biological medium for stimulation purposes.

  10. Comparing the magnetic resonant coupling radiofrequency stimulation to the traditional approaches: Ex-vivo tissue voltage measurement and electromagnetic simulation analysis

    Directory of Open Access Journals (Sweden)

    Sai Ho Yeung

    2015-09-01

    Full Text Available Recently, the design concept of magnetic resonant coupling has been adapted to electromagnetic therapy applications such as non-invasive radiofrequency (RF stimulation. This technique can significantly increase the electric field radiated from the magnetic coil at the stimulation target, and hence enhancing the current flowing through the nerve, thus enabling stimulation. In this paper, the developed magnetic resonant coupling (MRC stimulation, magnetic stimulation (MS and transcutaneous electrical nerve stimulation (TENS are compared. The differences between the MRC RF stimulation and other techniques are presented in terms of the operating mechanism, ex-vivo tissue voltage measurement and electromagnetic simulation analysis. The ev-vivo tissue voltage measurement experiment is performed on the compared devices based on measuring the voltage induced by electromagnetic induction at the tissue. The focusing effect, E field and voltage induced across the tissue, and the attenuation due to the increase of separation between the coil and the target are analyzed. The electromagnetic stimulation will also be performed to obtain the electric field and magnetic field distribution around the biological medium. The electric field intensity is proportional to the induced current and the magnetic field is corresponding to the electromagnetic induction across the biological medium. The comparison between the MRC RF stimulator and the MS and TENS devices revealed that the MRC RF stimulator has several advantages over the others for the applications of inducing current in the biological medium for stimulation purposes.

  11. Comparing the magnetic resonant coupling radiofrequency stimulation to the traditional approaches: Ex-vivo tissue voltage measurement and electromagnetic simulation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Yeung, Sai Ho; Pradhan, Raunaq; Feng, Xiaohua; Zheng, Yuanjin [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore)

    2015-09-15

    Recently, the design concept of magnetic resonant coupling has been adapted to electromagnetic therapy applications such as non-invasive radiofrequency (RF) stimulation. This technique can significantly increase the electric field radiated from the magnetic coil at the stimulation target, and hence enhancing the current flowing through the nerve, thus enabling stimulation. In this paper, the developed magnetic resonant coupling (MRC) stimulation, magnetic stimulation (MS) and transcutaneous electrical nerve stimulation (TENS) are compared. The differences between the MRC RF stimulation and other techniques are presented in terms of the operating mechanism, ex-vivo tissue voltage measurement and electromagnetic simulation analysis. The ev-vivo tissue voltage measurement experiment is performed on the compared devices based on measuring the voltage induced by electromagnetic induction at the tissue. The focusing effect, E field and voltage induced across the tissue, and the attenuation due to the increase of separation between the coil and the target are analyzed. The electromagnetic stimulation will also be performed to obtain the electric field and magnetic field distribution around the biological medium. The electric field intensity is proportional to the induced current and the magnetic field is corresponding to the electromagnetic induction across the biological medium. The comparison between the MRC RF stimulator and the MS and TENS devices revealed that the MRC RF stimulator has several advantages over the others for the applications of inducing current in the biological medium for stimulation purposes.

  12. Difference between healthy children and ADHD based on wavelet spectral analysis of nuclear magnetic resonance images

    International Nuclear Information System (INIS)

    González Gómez Dulce, I.; Moreno Barbosa, E.; Hernández, Mario Iván Martínez; Méndez, José Ramos; Silvia, Hidalgo Tobón; Pilar, Dies Suarez; Eduardo, Barragán Pérez; Benito, De Celis Alonso

    2014-01-01

    The main goal of this project was to create a computer algorithm based on wavelet analysis of region of homogeneity images obtained during resting state studies. Ideally it would automatically diagnose ADHD. Because the cerebellum is an area known to be affected by ADHD, this study specifically analysed this region. Male right handed volunteers (infants with ages between 7 and 11 years old) were studied and compared with age matched controls. Statistical differences between the values of the absolute integrated wavelet spectrum were found and showed significant differences (p<0.0015) between groups. This difference might help in the future to distinguish healthy from ADHD patients and therefore diagnose ADHD. Even if results were statistically significant, the small size of the sample limits the applicability of this methods as it is presented here, and further work with larger samples and using freely available datasets must be done

  13. Difference between healthy children and ADHD based on wavelet spectral analysis of nuclear magnetic resonance images

    Energy Technology Data Exchange (ETDEWEB)

    González Gómez Dulce, I., E-mail: isabeldgg@hotmail.com, E-mail: emoreno@fcfm.buap.mx, E-mail: mim@fcfm.buap.mx, E-mail: joserm84@gmail.com; Moreno Barbosa, E., E-mail: isabeldgg@hotmail.com, E-mail: emoreno@fcfm.buap.mx, E-mail: mim@fcfm.buap.mx, E-mail: joserm84@gmail.com; Hernández, Mario Iván Martínez, E-mail: isabeldgg@hotmail.com, E-mail: emoreno@fcfm.buap.mx, E-mail: mim@fcfm.buap.mx, E-mail: joserm84@gmail.com; Méndez, José Ramos, E-mail: isabeldgg@hotmail.com, E-mail: emoreno@fcfm.buap.mx, E-mail: mim@fcfm.buap.mx, E-mail: joserm84@gmail.com [Faculty of Physics and Mathematics, BUAP, Puebla, Pue. (Mexico); Silvia, Hidalgo Tobón [Hospital Infantil de México, Federico Gómez, Mexico DF. Mexico and Physics Department, Universidad Autónoma Metropolitana. Iztapalapa, Mexico DF. (Mexico); Pilar, Dies Suarez, E-mail: pilydies@yahoo.com, E-mail: neurodoc@prodigy.net.mx; Eduardo, Barragán Pérez, E-mail: pilydies@yahoo.com, E-mail: neurodoc@prodigy.net.mx [Hospital Infantil de México, Federico Gómez, Mexico DF. (Mexico); Benito, De Celis Alonso, E-mail: benileon@yahoo.com [Faculty of Physics and Mathematics, BUAP, Puebla, Pue. Mexico and Fundación para el Desarrollo Carlos Sigüenza. Puebla, Pue (Mexico)

    2014-11-07

    The main goal of this project was to create a computer algorithm based on wavelet analysis of region of homogeneity images obtained during resting state studies. Ideally it would automatically diagnose ADHD. Because the cerebellum is an area known to be affected by ADHD, this study specifically analysed this region. Male right handed volunteers (infants with ages between 7 and 11 years old) were studied and compared with age matched controls. Statistical differences between the values of the absolute integrated wavelet spectrum were found and showed significant differences (p<0.0015) between groups. This difference might help in the future to distinguish healthy from ADHD patients and therefore diagnose ADHD. Even if results were statistically significant, the small size of the sample limits the applicability of this methods as it is presented here, and further work with larger samples and using freely available datasets must be done.

  14. Difference between healthy children and ADHD based on wavelet spectral analysis of nuclear magnetic resonance images

    Science.gov (United States)

    González Gómez, Dulce I.; Moreno Barbosa, E.; Martínez Hernández, Mario Iván; Ramos Méndez, José; Hidalgo Tobón, Silvia; Dies Suarez, Pilar; Barragán Pérez, Eduardo; De Celis Alonso, Benito

    2014-11-01

    The main goal of this project was to create a computer algorithm based on wavelet analysis of region of homogeneity images obtained during resting state studies. Ideally it would automatically diagnose ADHD. Because the cerebellum is an area known to be affected by ADHD, this study specifically analysed this region. Male right handed volunteers (infants with ages between 7 and 11 years old) were studied and compared with age matched controls. Statistical differences between the values of the absolute integrated wavelet spectrum were found and showed significant differences (pADHD patients and therefore diagnose ADHD. Even if results were statistically significant, the small size of the sample limits the applicability of this methods as it is presented here, and further work with larger samples and using freely available datasets must be done.

  15. Nuclear magnetic resonance line-shape analysis and determination of exchange rates

    International Nuclear Information System (INIS)

    Rao, B.D.

    1989-01-01

    The fact that chemical exchange processes occur at rates that cover a broad range and produce readily detectable effects on the spectrum is one of the attractive features of high-resolution NMR. The description of these line shapes in the presence of spin-spin coupling requires the density matrix theory which is rather complex. Analysis of the line shapes usually needs computer simulations and is capable of providing reliable information on the exchange rates as well as spectral parameters in the absence of exchange. Simplified procedures, ignoring spin-spin coupling, often result in deviations in these exchange and spectral parameters determined. A step-by-step procedure is detailed in this chapter for setting up the matrices required for computing the line shapes of exchanges involving weakly coupled spin systems on the basis of the density matrix theory without the need for a detailed understanding of the theory. A knowledge of the energy level structure and allowed transitions in the NMR spectra of the individual weakly coupled spin systems is all that is required. The procedure is amenable to numerical computation. The group of illustrative examples chosen to demonstrate the development of the computational tools cover some of the commonly encountered cases of exchange from simple systems to rather complex ones. Such exchanges occur frequently in biological molecules, especially those involving enzyme-substrate complexes. In cases where the experimental line shapes are obtained with respectable precision, and the relevant exchange processes are unambiguously identifiable, the computer simulation method of line-shape analysis is capable of providing useful and incisive information. The example of the 31P exchanges in the adenylate kinase is illustrative of this point

  16. Parenchymal abnormalities in cerebral venous thrombosis: findings of magnetic resonance imaging and magnetic resonance angiography

    International Nuclear Information System (INIS)

    Ferreira, Clecia Santos; Pellini, Marcos; Boasquevisque, Edson; Souza, Luis Alberto M. de

    2006-01-01

    Objective: to determine the frequency and localization of parenchymal abnormalities in cerebral venous thrombosis on magnetic resonance imaging and magnetic resonance angiography as well as their correlation with the territory and affected venous drainage. Materials and methods: retrospective analysis (1996 to 2004) of 21 patients (3 male and 18 female) age range between 3 and 82 years (mean 40 years, median 36 years) with clinical and radiological diagnosis of cerebral venous thrombosis on magnetic resonance imaging and magnetic resonance angiography in 2D PC, 3D PC and contrast-enhanced 3D TOF sequences. The statistical analysis was performed with the qui-square test. Four patients had follow-up exams and three patients underwent digital subtraction angiography. Results: main predisposing factors were: infection, use of oral contraceptives, hormone replacement therapy and collagenosis. Predominant symptoms included: focal deficit, headache, alteration of consciousness level and seizures. Most frequent parenchymal manifestations were: cortical/subcortical edema or infarct, venous congestion and collateral circulation, meningeal enhancement and thalamic and basal ganglia edema or infarct. Occlusion occurred mainly in superior sagittal, left transverse, left sigmoid and straight sinuses. Cavernous sinus and cortical veins thrombosis are uncommon events. Conclusion: cerebral venous thrombosis is an uncommon cause of stroke, with favorable prognosis because of its reversibility. Diagnosis is highly dependent on the radiologist capacity to recognize the presentations of this disease, principally in cases where the diagnosis is suggested by parenchymal abnormalities rather than necessarily by visualization of the thrombus itself. An accurate and rapid diagnosis allows an immediate treatment, reducing the morbidity and mortality rates. (author)

  17. Resonance double magnetic bremsstrahlung in a strong magnetic field

    International Nuclear Information System (INIS)

    Fomin, P.I.; Kholodov, R.I.

    2003-01-01

    The possibility of resonance double magnetic bremsstrahlung in the approximation of weakly excited electron states in a strong external magnetic field is analyzed. The differential probability of this process in the Breit-Wigner form is obtained. The probability of double magnetic bremsstrahlung (second-order process of perturbation theory) is compared with the probability of magnetic bremsstrahlung (first-order process of perturbation theory)

  18. 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, ...

  19. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

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

  20. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... help detect certain chronic diseases of the nervous system, such as multiple sclerosis diagnose problems with the ... the magnet. Some MRI units, called short-bore systems , are designed so that the magnet does not ...

  1. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... MRI) of the head uses a powerful magnetic field, radio waves and a computer to produce detailed ... there’s a possibility you are pregnant. The magnetic field is not harmful, but it may cause some ...

  2. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... their nature and the strength of the MRI magnet. Many implanted devices will have a pamphlet explaining ... large cylinder-shaped tube surrounded by a circular magnet. Your child will lie on a moveable examination ...

  3. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... their nature and the strength of the MRI magnet. Many implanted devices will have a pamphlet explaining ... large cylinder-shaped tube surrounded by a circular magnet. You will lie on a moveable examination table ...

  4. Optimizing 4-Dimensional Magnetic Resonance Imaging Data Sampling for Respiratory Motion Analysis of Pancreatic Tumors

    Energy Technology Data Exchange (ETDEWEB)

    Stemkens, Bjorn, E-mail: b.stemkens@umcutrecht.nl [Department of Radiotherapy, University Medical Center Utrecht, Utrecht (Netherlands); Tijssen, Rob H.N. [Department of Radiotherapy, University Medical Center Utrecht, Utrecht (Netherlands); Senneville, Baudouin D. de [Imaging Division, University Medical Center Utrecht, Utrecht (Netherlands); L' Institut de Mathématiques de Bordeaux, Unité Mixte de Recherche 5251, Centre National de la Recherche Scientifique/University of Bordeaux, Bordeaux (France); Heerkens, Hanne D.; Vulpen, Marco van; Lagendijk, Jan J.W.; Berg, Cornelis A.T. van den [Department of Radiotherapy, University Medical Center Utrecht, Utrecht (Netherlands)

    2015-03-01

    Purpose: To determine the optimum sampling strategy for retrospective reconstruction of 4-dimensional (4D) MR data for nonrigid motion characterization of tumor and organs at risk for radiation therapy purposes. Methods and Materials: For optimization, we compared 2 surrogate signals (external respiratory bellows and internal MRI navigators) and 2 MR sampling strategies (Cartesian and radial) in terms of image quality and robustness. Using the optimized protocol, 6 pancreatic cancer patients were scanned to calculate the 4D motion. Region of interest analysis was performed to characterize the respiratory-induced motion of the tumor and organs at risk simultaneously. Results: The MRI navigator was found to be a more reliable surrogate for pancreatic motion than the respiratory bellows signal. Radial sampling is most benign for undersampling artifacts and intraview motion. Motion characterization revealed interorgan and interpatient variation, as well as heterogeneity within the tumor. Conclusions: A robust 4D-MRI method, based on clinically available protocols, is presented and successfully applied to characterize the abdominal motion in a small number of pancreatic cancer patients.

  5. Magnetic resonance imaging 4-D flow-based analysis of aortic hemodynamics in Turner syndrome.

    Science.gov (United States)

    Arnold, Raoul; Neu, Marie; Hirtler, Daniel; Gimpel, Charlotte; Markl, Michael; Geiger, Julia

    2017-04-01

    Cardiovascular surveillance is important in Turner syndrome because of the increased risk of aortic dilation and dissection with consecutively increased mortality. To compare 4-D flow MRI for the characterization of aortic 3-D flow patterns, dimensions and vessel wall parameters in pediatric patients with Turner syndrome and age-matched controls. We performed 4-D flow MRI measuring in vivo 3-D blood flow with coverage of the thoracic aorta in 25 patients with Turner syndrome and in 16 female healthy controls (age mean ± standard deviation were 16 ± 5 years and 17 ± 4 years, respectively). Blood flow was visualized by time-resolved 3-D path lines. Visual grading of aortic flow in terms of helices and vortices was performed by two independent observers. Quantitative analysis included measurement of aortic diameters, quantification of peak systolic wall shear stress, pulsatility index and oscillatory shear index at eight defined sites. Patients with Turner syndrome had significantly larger aortic diameters normalized to BSA, increased vortices in the ascending aorta and elevated helix flow in the ascending and descending aorta compared to controls (all PTurner patients compared to controls (p=0.02, p=0.002 and p=0.01 respectively). Four-dimensional flow MRI provides new insights into the altered aortic hemodynamics and wall shear stress that could have an impact on the development of aortic dissections.

  6. Quantitative analysis of magnetic resonance imaging susceptibility artifacts caused by neurosurgical biomaterials. Comparison of 0.5, 1.5, and 3.0 tesla magnetic fields

    International Nuclear Information System (INIS)

    Matsuura, Hideki; Inoue, Takashi; Ogasawara, Kuniaki; Sasaki, Makoto; Konno, Hiromu; Kuzu, Yasutaka; Nishimoto, Hideaki; Ogawa, Akira

    2005-01-01

    Magnetic resonance (MR) imaging is an important diagnostic tool for neurosurgical diseases but susceptibility artifacts caused by biomaterial instrumentation frequently causes difficulty in visualizing postoperative changes. The susceptibility artifacts caused by neurosurgical biomaterials were compared quantitatively by 0.5, 1.5, and 3.0 Tesla MR imaging. MR imaging of uniform size and shape of pieces ceramic (zirconia), pure titanium, titanium alloy, and cobalt-based alloy was performed at 0.5, 1.5, and 3.0 Tesla. A linear region of interest was defined across the center of the biomaterial in the transverse direction, and the susceptibility artifact diameter was calculated. Susceptibility artifacts developed around all biomaterials at all magnetic field strengths. The artifact diameters caused by pure titanium, titanium alloy, and cobalt-based alloy increased in the order of 0.5, 1.5, to 3.0 Tesla magnetic fields. The artifact diameter of ceramic was not influenced by magnetic field strength, and was the smallest of all biomaterials at all magnetic field strengths. The artifacts caused by biomaterials except ceramic increase with the magnetic field strength. Ceramic instrumentation will minimize artifacts in all magnetic fields. (author)

  7. Magnetic resonance spectroscopy as an imaging method

    International Nuclear Information System (INIS)

    Bomsdorf, H.; Imme, M.; Jensen, D.; Kunz, D.; Menhardt, W.; Ottenberg, K.; Roeschmann, P.; Schmidt, K.H.; Tschendel, O.; Wieland, J.

    1990-01-01

    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 1 H and 13 C 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 [de

  8. Magnetic resonance imaging 4-D flow-based analysis of aortic hemodynamics in Turner syndrome

    International Nuclear Information System (INIS)

    Arnold, Raoul; Neu, Marie; Hirtler, Daniel; Gimpel, Charlotte; Markl, Michael; Geiger, Julia

    2017-01-01

    Cardiovascular surveillance is important in Turner syndrome because of the increased risk of aortic dilation and dissection with consecutively increased mortality. To compare 4-D flow MRI for the characterization of aortic 3-D flow patterns, dimensions and vessel wall parameters in pediatric patients with Turner syndrome and age-matched controls. We performed 4-D flow MRI measuring in vivo 3-D blood flow with coverage of the thoracic aorta in 25 patients with Turner syndrome and in 16 female healthy controls (age mean ± standard deviation were 16 ± 5 years and 17 ± 4 years, respectively). Blood flow was visualized by time-resolved 3-D path lines. Visual grading of aortic flow in terms of helices and vortices was performed by two independent observers. Quantitative analysis included measurement of aortic diameters, quantification of peak systolic wall shear stress, pulsatility index and oscillatory shear index at eight defined sites. Patients with Turner syndrome had significantly larger aortic diameters normalized to BSA, increased vortices in the ascending aorta and elevated helix flow in the ascending and descending aorta compared to controls (all P<0.03). Patients with abnormal helical or vortical flow in the ascending aorta had significantly larger diameters of the ascending aorta (P<0.03). Peak systolic wall shear stress, pulsatility index and oscillatory shear index were significantly lower in Turner patients compared to controls (p=0.02, p=0.002 and p=0.01 respectively). Four-dimensional flow MRI provides new insights into the altered aortic hemodynamics and wall shear stress that could have an impact on the development of aortic dissections. (orig.)

  9. Magnetic resonance imaging 4-D flow-based analysis of aortic hemodynamics in Turner syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, Raoul [University Medical Center Heidelberg, Department of Congenital Heart Disease and Pediatric Cardiology, Heidelberg (Germany); Neu, Marie [University Medical Center, Department of Pediatric Hematology/Oncology/Hemostaseology, Mainz (Germany); Hirtler, Daniel [University of Freiburg, Department of Congenital Heart Defects and Pediatric Cardiology, Heart Center, Freiburg im Breisgau (Germany); Gimpel, Charlotte [Center for Pediatrics, Medical Center - University of Freiburg, Department of General Pediatrics, Adolescent Medicine and Neonatology, Freiburg im Breisgau (Germany); Markl, Michael [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Northwestern University, Department of Biomedical Engineering, McCormick School of Engineering, Chicago, IL (United States); Geiger, Julia [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); University Children' s Hospital, Department of Radiology, Zuerich (Switzerland)

    2017-04-15

    Cardiovascular surveillance is important in Turner syndrome because of the increased risk of aortic dilation and dissection with consecutively increased mortality. To compare 4-D flow MRI for the characterization of aortic 3-D flow patterns, dimensions and vessel wall parameters in pediatric patients with Turner syndrome and age-matched controls. We performed 4-D flow MRI measuring in vivo 3-D blood flow with coverage of the thoracic aorta in 25 patients with Turner syndrome and in 16 female healthy controls (age mean ± standard deviation were 16 ± 5 years and 17 ± 4 years, respectively). Blood flow was visualized by time-resolved 3-D path lines. Visual grading of aortic flow in terms of helices and vortices was performed by two independent observers. Quantitative analysis included measurement of aortic diameters, quantification of peak systolic wall shear stress, pulsatility index and oscillatory shear index at eight defined sites. Patients with Turner syndrome had significantly larger aortic diameters normalized to BSA, increased vortices in the ascending aorta and elevated helix flow in the ascending and descending aorta compared to controls (all P<0.03). Patients with abnormal helical or vortical flow in the ascending aorta had significantly larger diameters of the ascending aorta (P<0.03). Peak systolic wall shear stress, pulsatility index and oscillatory shear index were significantly lower in Turner patients compared to controls (p=0.02, p=0.002 and p=0.01 respectively). Four-dimensional flow MRI provides new insights into the altered aortic hemodynamics and wall shear stress that could have an impact on the development of aortic dissections. (orig.)

  10. Deltoid muscle shape analysis with magnetic resonance imaging in patients with chronic rotator cuff tears.

    Science.gov (United States)

    Meyer, Dominik C; Rahm, Stefan; Farshad, Mazda; Lajtai, Georg; Wieser, Karl

    2013-08-19

    It seems appropriate to assume, that for a full and strong global shoulder function a normally innervated and active deltoid muscle is indispensable. We set out to analyse the size and shape of the deltoid muscle on MR-arthrographies, and analyse its influence on shoulder function and its adaption (i.e. atrophy) for reduced shoulder function. The fatty infiltration (Goutallier stages), atrophy (tangent sign) and selective myotendinous retraction of the rotator cuff, as well as the thickness and the area of seven anatomically defined segments of the deltoid muscle were measured on MR-arthrographies and correlated with shoulder function (i.e. active abduction). Included were 116 patients, suffering of a rotator cuff tear with shoulder mobility ranging from pseudoparalysis to free mobility. Kolmogorov-Smirnov test was used to determine the distribution of the data before either Spearman or Pearson correlation and a multiple regression was applied to reveal the correlations. Our developed method for measuring deltoid area and thickness showed to be reproducible with excellent interobserver correlations (r = 0.814-0.982).The analysis of influencing factors on active abduction revealed a weak influence of the amount of SSP tendon (r = -0.25; p muscle retraction (r = -0.27; p muscle infiltration (GFDI: r = -0.36; p muscle shape with the degree of active glenohumeral abduction. Furthermore, long-standing rotator cuff tears did not appear to influence the deltoid shape, i.e. did not lead to muscle atrophy. Our data support that in chronic rotator cuff tears, there seems to be no disadvantage to exhausting conservative treatment and to delay implantation of reverse total shoulder arthroplasty, as the shape of deltoid muscle seems only to be influenced by natural aging, but to be independent of reduced shoulder motion.

  11. Magnetic islands created by resonant helical windings

    International Nuclear Information System (INIS)

    Fernandes, A.S.; Heller, M.V.; Caldas, I.L.

    1986-01-01

    The triggering of disruptive instabilities by resonant helical windings in large aspect-ratio tokamaks is associated to destruction of magnetic surfaces. The Chirikov condition is applied to estimate analytically the helical winding current thresholds for ergodization of the magnetic field lines. (Autor) [pt

  12. Topical questions in magnetic resonance imaging

    International Nuclear Information System (INIS)

    Andrew, E.R.; Florida Univ., Gainesville, FL; Florida Univ., Gainesville, FL

    1989-01-01

    This paper examines a number of practical questions concerning magnetic resonance imaging. These include the choice of operating magnetic field strength, the problem of siting and screening, a procedure for securing precise slice selection and the use of paramagnetic contrast agents. (author). 5 refs

  13. Cost-effectiveness analysis of endoscopic ultrasound versus magnetic resonance cholangiopancreatography in patients with suspected common bile duct stones.

    Directory of Open Access Journals (Sweden)

    Stephen Morris

    Full Text Available Patients with suspected common bile duct (CBD stones are often diagnosed using endoscopic retrograde cholangiopancreatography (ERCP, an invasive procedure with risk of significant complications. Using endoscopic ultrasound (EUS or Magnetic Resonance CholangioPancreatography (MRCP first to detect CBD stones can reduce the risk of unnecessary procedures, cut complications and may save costs.This study sought to compare the cost-effectiveness of initial EUS or MRCP in patients with suspected CBD stones.This study is a model based cost-utility analysis estimating mean costs and quality-adjusted life years (QALYs per patient from the perspective of the UK National Health Service (NHS over a 1 year time horizon. A decision tree model was constructed and populated with probabilities, outcomes and cost data from published sources, including one-way and probabilistic sensitivity analyses.Using MRCP to select patients for ERCP was less costly than using EUS to select patients or proceeding directly to ERCP ($1299 versus $1753 and $1781, respectively, with similar QALYs accruing to each option (0.998, 0.998 and 0.997 for EUS, MRCP and direct ERCP, respectively. Initial MRCP was the most cost-effective option with the highest monetary net benefit, and this result was not sensitive to model parameters. MRCP had a 61% probability of being cost-effective at $29,000, the maximum willingness to pay for a QALY commonly used in the UK.From the perspective of the UK NHS, MRCP was the most cost-effective test in the diagnosis of CBD stones.

  14. Analysis of spatial and temporal dynamics of xylem refilling in Acer rubrum L. using magnetic resonance imaging (MRI.

    Directory of Open Access Journals (Sweden)

    Maciej Andrzej Zwieniecki

    2013-07-01

    Full Text Available We report results of an analysis of embolism formation and subsequent refilling observed in stems of Acer rubrum L. using magnetic resonance imaging (MRI. MRI is one of the very few techniques that can provide direct non-destructive observations of the water content within opaque biological materials at a micrometer resolution. Thus, it has been used to determine temporal dynamics and water distributions within xylem tissue. In this study, we found good agreement between MRI measures of pixel brightness to assess xylem liquid water content and the percent loss in hydraulic conductivity (PLC in response to water stress (P50 values of 2.51 and 2.70 for MRI and PLC, respectively. These data provide strong support that pixel brightness is well correlated to PLC and can be used as a proxy of PLC even when single vessels cannot be resolved on the image. Pressure induced embolism in moderately stressed plants resulted in initial drop of pixel brightness. This drop was followed by brightness gain over 100 minutes following pressure application suggesting that plants can restore water content in stem after induced embolism. This recovery was limited only to current year wood ring; older wood did not show signs of recovery within the length of experiment (16 hours. In vivo MRI observations of the xylem of moderately stressed (~-0.5 MPa A. rubrum stems revealed evidence of a spontaneous embolism formation followed by rapid refilling (~30 minutes. Spontaneous (not induced embolism formation was observed only once, despite over 60 hours of continuous MRI observations made on several plants. Thus this observation provide evidence for presence of naturally occurring embolism-refilling cycle in A. rubrum, but it is impossible to infer any conclusions in relation to its frequency in nature.

  15. Analysis of spatial and temporal dynamics of xylem refilling in Acer rubrum L. using magnetic resonance imaging.

    Science.gov (United States)

    Zwieniecki, Maciej A; Melcher, Peter J; Ahrens, Eric T

    2013-01-01

    We report results of an analysis of embolism formation and subsequent refilling observed in stems of Acer rubrum L. using magnetic resonance imaging (MRI). MRI is one of the very few techniques that can provide direct non-destructive observations of the water content within opaque biological materials at a micrometer resolution. Thus, it has been used to determine temporal dynamics and water distributions within xylem tissue. In this study, we found good agreement between MRI measures of pixel brightness to assess xylem liquid water content and the percent loss in hydraulic conductivity (PLC) in response to water stress (P50 values of 2.51 and 2.70 for MRI and PLC, respectively). These data provide strong support that pixel brightness is well correlated to PLC and can be used as a proxy of PLC even when single vessels cannot be resolved on the image. Pressure induced embolism in moderately stressed plants resulted in initial drop of pixel brightness. This drop was followed by brightness gain over 100 min following pressure application suggesting that plants can restore water content in stem after induced embolism. This recovery was limited only to current-year wood ring; older wood did not show signs of recovery within the length of experiment (16 h). In vivo MRI observations of the xylem of moderately stressed (~-0.5 MPa) A. rubrum stems revealed evidence of a spontaneous embolism formation followed by rapid refilling (~30 min). Spontaneous (not induced) embolism formation was observed only once, despite over 60 h of continuous MRI observations made on several plants. Thus this observation provide evidence for the presence of naturally occurring embolism-refilling cycle in A. rubrum, but it is impossible to infer any conclusions in relation to its frequency in nature.

  16. Bone bruise in acute traumatic patellar dislocation: volumetric magnetic resonance imaging analysis with follow-up mean of 12 months

    Energy Technology Data Exchange (ETDEWEB)

    Paakkala, Antti; Paakkala, Timo [Tampere University Hospital, Department of Radiology, Tampere (Finland); Sillanpaeae, Petri; Maeenpaeae, Heikki [Tampere University Hospital, Department of Orthopaedics and Traumatology, Tampere (Finland); Huhtala, Heini [University of Tampere, School of Public Health, Tampere (Finland)

    2010-07-15

    The aim of the study was to assess volumetric analysis of bone bruises in acute primary traumatic patellar dislocation by magnetic resonance imaging (MRI) and resolving resolution of bruises in follow-up MRI. MRI was performed in 23 cases. A follow-up examination was done at a mean of 12 months after dislocation. Volumes of patellar and femur bruises for every patient were evaluated separately by two musculoskeletal radiologists, and mean values of the bruises were assessed. Other MRI findings were evaluated, together with agreement by consensus. Bone bruise volumes were compared with other MR findings. In the acute study 100% of patients showed bruising of the lateral femoral condyle and 96% bruising of the patella. The bruise was located at the medial femoral condyle in 30% and at the patellar median ridge in 74% of patients. The median volume of the femoral bruise was 25,831 mm{sup 3} and of the patellar bruise 2,832 mm{sup 3}. At the follow-up study 22% of patients showed bruising of the lateral femoral condyle and 39% bruising of the patella, the median volumes of the bruises being 5,062 mm{sup 3} and 1,380 mm{sup 3}, respectively. Larger patellar bruise volume correlated with larger femur bruise volume in the acute (r=0.389, P=0.074) and the follow-up (r=1.000, P<0.01) studies. Other MRI findings did not correlate significantly with bone bruise volumes. Bone bruising is the commonest finding in cases of acute patellar dislocation, being seen even 1 year after trauma and indicating significant bone trabecular injury in the patellofemoral joint. A large bruise volume may be associated with subsequent chondral lesion progression at the patella. We concluded that the measurement of bone bruise volume in patients with acute patellar dislocation is a reproducible method but requires further studies to evaluate its clinical use. (orig.)

  17. Bone bruise in acute traumatic patellar dislocation: volumetric magnetic resonance imaging analysis with follow-up mean of 12 months

    International Nuclear Information System (INIS)

    Paakkala, Antti; Paakkala, Timo; Sillanpaeae, Petri; Maeenpaeae, Heikki; Huhtala, Heini

    2010-01-01

    The aim of the study was to assess volumetric analysis of bone bruises in acute primary traumatic patellar dislocation by magnetic resonance imaging (MRI) and resolving resolution of bruises in follow-up MRI. MRI was performed in 23 cases. A follow-up examination was done at a mean of 12 months after dislocation. Volumes of patellar and femur bruises for every patient were evaluated separately by two musculoskeletal radiologists, and mean values of the bruises were assessed. Other MRI findings were evaluated, together with agreement by consensus. Bone bruise volumes were compared with other MR findings. In the acute study 100% of patients showed bruising of the lateral femoral condyle and 96% bruising of the patella. The bruise was located at the medial femoral condyle in 30% and at the patellar median ridge in 74% of patients. The median volume of the femoral bruise was 25,831 mm 3 and of the patellar bruise 2,832 mm 3 . At the follow-up study 22% of patients showed bruising of the lateral femoral condyle and 39% bruising of the patella, the median volumes of the bruises being 5,062 mm 3 and 1,380 mm 3 , respectively. Larger patellar bruise volume correlated with larger femur bruise volume in the acute (r=0.389, P=0.074) and the follow-up (r=1.000, P<0.01) studies. Other MRI findings did not correlate significantly with bone bruise volumes. Bone bruising is the commonest finding in cases of acute patellar dislocation, being seen even 1 year after trauma and indicating significant bone trabecular injury in the patellofemoral joint. A large bruise volume may be associated with subsequent chondral lesion progression at the patella. We concluded that the measurement of bone bruise volume in patients with acute patellar dislocation is a reproducible method but requires further studies to evaluate its clinical use. (orig.)

  18. Can Diffusion-weighted Magnetic Resonance Imaging Predict Survival in Patients with Cervical Cancer? A Meta-Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yu-Ting, E-mail: wangyuting_330@163.com; Li, Ying-Chun, E-mail: anicespringspring@163.com; Yin, Long-Lin, E-mail: yinlonglin@163.com; Pu, Hong, E-mail: ph196797@163.com

    2016-12-15

    Highlights: • DWI may serve as a prognostic factor in patients with cervical cancer. • Unfavorable DWI results (mostly low ADC) were associated with higher risks of tumor recurrence. • A quantified ADC was shown to be a suitable candidate indicator. - Abstract: Objective: Although diffusion-weighted magnetic resonance imaging (DWI) has been widely used in the diagnosis of cervical cancer, whether it can predict disease recurrence or survival remains inconclusive. This study aimed to systematically evaluate whether DWI can serve as a reliable prognostic predictor in patients with cervical cancer. Methods: PubMed, the MEDLINE database and the Cochrane Library were searched for DWI studies with >12 months of prognostic data in patients with cervical cancer. Endpoints included tumor recurrence and death. Methodological quality was assessed using the Quality in Prognostic Studies (QUIPS) tool. Combined estimates of hazard ratios (HRs) were derived. Results: Nine studies involving a total of 796 patients (mean/median age from 45.0 years to 62.9 years) met the inclusion criteria. Methodological quality was relatively high. Eight of the nine studies employed apparent diffusion coefficient (ADC) as an indicator of DWI results. Using disease-free survival (DFS) as an outcome measure, nine studies yielded a combined HR of 1.55 (95% confidence interval (CI): 1.23–1.95), and seven studies that employed pretreatment DWI yielded a combined HR of 1.50 (95% CI: 1.03–2.19), which indicated that unfavorable DWI results were associated with an approximately 1.50–1.55-fold higher risk of tumor recurrence. The two studies investigating the impact of DWI results on overall survival (OS) reported HRs of 7.20 and 2.17, respectively. Conclusion: DWI may serve as a predictor of tumor recurrence in patients with cervical cancer as showed by meta-analysis, and the quantified ADC as a suitable candidate indicator.

  19. Connecting imaging mass spectrometry and magnetic resonance imaging-based anatomical atlases for automated anatomical interpretation and differential analysis.

    Science.gov (United States)

    Verbeeck, Nico; Spraggins, Jeffrey M; Murphy, Monika J M; Wang, Hui-Dong; Deutch, Ariel Y; Caprioli, Richard M; Van de Plas, Raf

    2017-07-01

    Imaging mass spectrometry (IMS) is a molecular imaging technology that can measure thousands of biomolecules concurrently without prior tagging, making it particularly suitable for exploratory research. However, the data size and dimensionality often makes thorough extraction of relevant information impractical. To help guide and accelerate IMS data analysis, we recently developed a framework that integrates IMS measurements with anatomical atlases, opening up opportunities for anatomy-driven exploration of IMS data. One example is the automated anatomical interpretation of ion images, where empirically measured ion distributions are automatically decomposed into their underlying anatomical structures. While offering significant potential, IMS-atlas integration has thus far been restricted to the Allen Mouse Brain Atlas (AMBA) and mouse brain samples. Here, we expand the applicability of this framework by extending towards new animal species and a new set of anatomical atlases retrieved from the Scalable Brain Atlas (SBA). Furthermore, as many SBA atlases are based on magnetic resonance imaging (MRI) data, a new registration pipeline was developed that enables direct non-rigid IMS-to-MRI registration. These developments are demonstrated on protein-focused FTICR IMS measurements from coronal brain sections of a Parkinson's disease (PD) rat model. The measurements are integrated with an MRI-based rat brain atlas from the SBA. The new rat-focused IMS-atlas integration is used to perform automated anatomical interpretation and to find differential ions between healthy and diseased tissue. IMS-atlas integration can serve as an important accelerator in IMS data exploration, and with these new developments it can now be applied to a wider variety of animal species and modalities. This article is part of a Special Issue entitled: MALDI Imaging, edited by Dr. Corinna Henkel and Prof. Peter Hoffmann. Copyright © 2017. Published by Elsevier B.V.

  20. Basis of the nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Bahceli, S.

    1996-08-01

    The aim of this book which is translated from English language is to explain the physical and mathematical basis of nuclear magnetic resonance (NMR). There are nine chapters covering different aspects of NMR. In the firs chapter fundamental concepts of quantum mechanics are given at a level suitable for readers to understand NMR fully. The remaining chapters discuss the magnetic properties of nucleus, the interactions between atoms and molecules, continuous wave NMR, pulsed NMR, nuclear magnetic relaxation and NMR of liquids

  1. A quantitative analysis of the diurnal evolution of Ionospheric Alfvén resonator magnetic resonance features and calculation of changing IAR parameters

    Directory of Open Access Journals (Sweden)

    S. R. Hebden

    2005-07-01

    Full Text Available Resonance features of the Ionospheric Alfvén Resonator (IAR can be observed in pulsation magnetometer data from Sodankylä, Finland using dynamic spectra visualizations. IAR resonance features were identified on 13 of 30 days in October 1998, with resonance structures lasting for 3 or more hours over 10 intervals. The diurnal evolution of the harmonic features was quantified for these 10 intervals using a manual cursor-clicking technique. The resonance features displayed strong linear relationships between harmonic frequency and harmonic number for all of the time intervals studied, enabling a homogeneous cavity model for the IAR to be adopted to interpret the data. This enabled the diurnal variation of the effective size of the IAR to be obtained for each of the 10 time intervals. The average effective size was found to be 530 km, and to have an average variation of 32% over each time interval: small compared to the average variation in Alfvén velocity of 61%. Thus the diurnal variation of the harmonics is chiefly caused by the changing plasma density within the IAR due to changing insolation. This study confirms Odzimek (2004 that the dominating factor affecting the IAR eigenfrequencies is the variation in the Alfvén velocity at the F-layer ion-density peak, with the changing IAR size affecting the IAR eigenfrequencies to a smaller extent. Another IAR parameter was derived from the analysis of the IAR resonance features associated with the phase matching structure of the standing waves in the IAR. This parameter varied over the time intervals studied by 20% on average, possibly due to changing ionospheric conductivity. Keywords. Ionosphere (Auroral ionosphere;Wave propagation – Radio science (Electromagnetic noise and interference

  2. Magnetic nanoparticles in magnetic resonance imaging and diagnostics.

    Science.gov (United States)

    Rümenapp, Christine; Gleich, Bernhard; Haase, Axel

    2012-05-01

    Magnetic nanoparticles are useful as contrast agents for magnetic resonance imaging (MRI). Paramagnetic contrast agents have been used for a long time, but more recently superparamagnetic iron oxide nanoparticles (SPIOs) have been discovered to influence MRI contrast as well. In contrast to paramagnetic contrast agents, SPIOs can be functionalized and size-tailored in order to adapt to various kinds of soft tissues. Although both types of contrast agents have a inducible magnetization, their mechanisms of influence on spin-spin and spin-lattice relaxation of protons are different. A special emphasis on the basic magnetism of nanoparticles and their structures as well as on the principle of nuclear magnetic resonance is made. Examples of different contrast-enhanced magnetic resonance images are given. The potential use of magnetic nanoparticles as diagnostic tracers is explored. Additionally, SPIOs can be used in diagnostic magnetic resonance, since the spin relaxation time of water protons differs, whether magnetic nanoparticles are bound to a target or not.

  3. Magnetic resonance imaging of the fetal brain.

    Science.gov (United States)

    Tee, L Mf; Kan, E Yl; Cheung, J Cy; Leung, W C

    2016-06-01

    This review covers the recent literature on fetal brain magnetic resonance imaging, with emphasis on techniques, advances, common indications, and safety. We conducted a search of MEDLINE for articles published after 2010. The search terms used were "(fetal OR foetal OR fetus OR foetus) AND (MR OR MRI OR [magnetic resonance]) AND (brain OR cerebral)". Consensus statements from major authorities were also included. As a result, 44 relevant articles were included and formed the basis of this review. One major challenge is fetal motion that is largely overcome by ultra-fast sequences. Currently, single-shot fast spin-echo T2-weighted imaging remains the mainstay for motion resistance and anatomical delineation. Recently, a snap-shot inversion recovery sequence has enabled robust T1-weighted images to be obtained, which is previously a challenge for standard gradient-echo acquisitions. Fetal diffusion-weighted imaging, diffusion tensor imaging, and magnetic resonance spectroscopy are also being developed. With multiplanar capabilities, superior contrast resolution and field of view, magnetic resonance imaging does not have the limitations of sonography, and can provide additional important information. Common indications include ventriculomegaly, callosum and posterior fossa abnormalities, and twin complications. There are safety concerns about magnetic resonance-induced heating and acoustic damage but current literature showed no conclusive evidence of deleterious fetal effects. The American College of Radiology guideline states that pregnant patients can be accepted to undergo magnetic resonance imaging at any stage of pregnancy if risk-benefit ratio to patients warrants that the study be performed. Magnetic resonance imaging of the fetal brain is a safe and powerful adjunct to sonography in prenatal diagnosis. It can provide additional information that aids clinical management, prognostication, and counselling.

  4. Magnetic resonance imaging: effects of magnetic field strength

    International Nuclear Information System (INIS)

    Crooks, L.E.; Arakawa, M.; Hoenninger, J.; McCarten, B.; Watts, J.; Kaufman, L.

    1984-01-01

    Magnetic resonance images of the head, abdomen, and pelvis of normal adult men were obtained using varying magnetic field strength, and measurements of T1 and T2 relaxations and of signal-to-noise (SN) ratios were determined. For any one spin echo sequence, gray/white matter contrast decreases and muscle/fat contrast increases with field. SN levels rise rapidly up to 3.0 kgauss and then change more slowly, actually dropping for muscle. The optimum field for magnetic resonance imaging depends on tissue type, body part, and imaging sequence, so that it does not have a unique value. Magnetic resonance systems that operate in the 3.0-5.0 kgauss range achieve most or all of the gains that can be achieved by higher magnetic fields

  5. A magnet without a magnetic circuit, of high homogeneity, specially for nuclear magnetic resonance images

    International Nuclear Information System (INIS)

    Barjhoux, Yves.

    1981-01-01

    This invention concerns a high homogeneity, double access magnet without a magnetic circuit. It is specially adapted for nuclear magnetic resonance (N.M.R.) imagery. Another advantage worth stressing resides in the possibilities of NMR in biochemical analysis which will enable, for instance, cancerous tumours to be detected in vivo. In order to increase the NMR signal ratio over background noise, it is necessary to increase the homogeneity of the B 0 orientating magnetic field. This magnetic field must orientate the nuclear magnetic moments of the elementary particles which compose the body being examined and in particular the protons. It must therefore be relatively constant in intensity and direction in the entire domain of the examination [fr

  6. Development of a Support Vector Machine - Based Image Analysis System for Focal Liver Lesions Classification in Magnetic Resonance Images

    International Nuclear Information System (INIS)

    Gatos, I; Tsantis, S; Kagadis, G; Karamesini, M; Skouroliakou, A

    2015-01-01

    Purpose: The design and implementation of a computer-based image analysis system employing the support vector machine (SVM) classifier system for the classification of Focal Liver Lesions (FLLs) on routine non-enhanced, T2-weighted Magnetic Resonance (MR) images. Materials and Methods: The study comprised 92 patients; each one of them has undergone MRI performed on a Magnetom Concerto (Siemens). Typical signs on dynamic contrast-enhanced MRI and biopsies were employed towards a three class categorization of the 92 cases: 40-benign FLLs, 25-Hepatocellular Carcinomas (HCC) within Cirrhotic liver parenchyma and 27-liver metastases from Non-Cirrhotic liver. Prior to FLLs classification an automated lesion segmentation algorithm based on Marcov Random Fields was employed in order to acquire each FLL Region of Interest. 42 texture features derived from the gray-level histogram, co-occurrence and run-length matrices and 12 morphological features were obtained from each lesion. Stepwise multi-linear regression analysis was utilized to avoid feature redundancy leading to a feature subset that fed the multiclass SVM classifier designed for lesion classification. SVM System evaluation was performed by means of leave-one-out method and ROC analysis. Results: Maximum accuracy for all three classes (90.0%) was obtained by means of the Radial Basis Kernel Function and three textural features (Inverse- Different-Moment, Sum-Variance and Long-Run-Emphasis) that describe lesion's contrast, variability and shape complexity. Sensitivity values for the three classes were 92.5%, 81.5% and 96.2% respectively, whereas specificity values were 94.2%, 95.3% and 95.5%. The AUC value achieved for the selected subset was 0.89 with 0.81 - 0.94 confidence interval. Conclusion: The proposed SVM system exhibit promising results that could be utilized as a second opinion tool to the radiologist in order to decrease the time/cost of diagnosis and the need for patients to undergo invasive

  7. Diagnostic value of 3D time-of-flight magnetic resonance angiography for detecting intracranial aneurysm: a meta-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Liu, HaiFeng; Xu, YongSheng [First Hospital of LanZhou University, Department of Radiology, Lanzhou, Gansu (China); First Clinical Medical College of LanZhou University, Lanzhou, Gansu (China); Xun, YangQin [Lanzhou University, Evidence-based Medicine Center, Lanzhou (China); Dou, Yu; Wang, ShuaiWen; Lu, XingRu; Lei, JunQiang [First Hospital of LanZhou University, Department of Radiology, Lanzhou, Gansu (China)

    2017-11-15

    This meta-analysis is to comprehensively evaluate the diagnostic performance of three-dimensional time-of-flight magnetic resonance angiography (3D-TOF-MRA) for detecting intracranial aneurysm (IA). PubMed, Embase, Web of Science, and the Cochrane library were systematically searched for retrieving eligible studies. Study inclusion, data extraction, and risk of bias assessment were performed by two researchers independently. Pooled sensitivity (SEN), specificity (SPE), positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and area under the curve (AUC) were calculated to assess the diagnostic value. In addition, heterogeneity and subgroup analysis were carried out. In total, 18 studies comprising 3463 patients were selected. The results of 3D-TOF-MRA for diagnosing IA were SEN 0.89 (95% CI 0.82-0.94), SPE 0.94 (0.86-0.97), PLR 13.79 (5.92-32.12), NLR 0.11 (0.07-0.19), DOR 121.90 (38.81-382.94), and AUC 0.96 (0.94-0.98), respectively. In the subgroup analysis, studies without subarachnoid hemorrhage (SAH) tend to perform statistical significantly better (P < 0.05) in detecting IAs than studies with SAH 0.99 (0.98-1.00) vs. 0.89 (0.86-0.91). The diagnostic value of studies with a two-image reconstruction method was higher than studies with only one image reconstruction method: 0.99 (0.98-1.00) vs. 0.91 (0.89-0.94) with P < 0.05. The 3D-TOF-MRA had better SEN in aneurysms > 3 mm than the aneurysms ≤ 3 mm in diameter: 0.89 (0.87-0.92) vs. 0.78 (0.71-0.84) with P < 0.05. This study demonstrated that 3D-TOF-MRA has an excellent diagnostic performance for the overall assessment of IA and may serve as an alternative for further patient management with IA. (orig.)

  8. Diagnostic apparatus employing nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Hoshino, K.; Yamada, N.; Yoshitome, E.; Matsuura, H.

    1987-01-01

    An NMR diagnostic apparatus is described comprising means for applying a primary magnetic field to a subject; means for applying RF pulses to the subject to give nuclear magnetic resonance to the nuclei of atoms in the subject; means for applying gradient magnetic fields to project an NMR signal of the nuclei at least in one direction; means for observing the NMR signal projected by the gradient magnetic fields applying means; and arithmetic means for constructing a distribution of information on resonance energy as an image from an output signal from the observing means; wherein the gradient magnetic fields applying means comprises means for applying the gradient magnetic fields at a predetermined time and for not applying the gradient magnetic fields at another predetermined time, during the time period of one view; and wherein the gradient magnetic fields applying means further comprises means for measuring the NMR signal during the predetermined time when the gradient magnetic fields are applied, and means for measuring the intensity of the primary magnetic field during the other predetermined time when no gradient magnetic fields are applied

  9. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... vision or seizures help detect certain chronic diseases of the nervous system, such as multiple sclerosis diagnose problems with the ... moveable examination table that slides into the center of the magnet. Some MRI units, called short-bore systems , are designed so that the magnet does not ...

  10. 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.

  11. Analysis of energy metabolism of the rabbit liver in obstructive jaundice using 31P magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Kawasaki, Toshihiko; Moriyasu, Fuminori; Ban, Nobuyuki

    1987-01-01

    Phosphorus-31 magnetic resonance spectroscopy was used to assess the changes in hepatic high-energy phosphate metabolites in rabbits with obstructive jaundice. The rabbits, which had undergone operative ligation of the common bile duct, were studied using a 2.0 Tesla whole-body magnetic resonance imager. Comparison of the peak phosphorus signal values relative to α-ATP showed that the peak phosphodiester and γ-ATP values in the livers of the one-day-after-ligation group were significantly lower than those in the control group, and the peak phosphomonoester and phosphodiester values in the five-days-after-ligation group were larger than those in the control group, but not significantly. Comparison of the peak T 1 values in the one-day-after-ligation group with those of the control group revealed that the T 1 value of phosphodiester was significantly larger than that in control group. It is suggested that dysfunction of phospholipid metabolism appears in the early phase of hepatic dysfunction due to obstructive jaundice. (author)

  12. Magnetic resonance spectroscopic imaging in breast cancer detection: possibilities beyond the conventional theoretical framework for data analysis

    Energy Technology Data Exchange (ETDEWEB)

    Belkic, Karen E-mail: karen.belkic@radfys.ki.se

    2004-06-01

    Magnetic Resonance Spectroscopic Imaging (MRSI) is a promising method for breast cancer diagnosis, providing, in addition to the anatomic picture, complementary biochemical and physiologic information in the form of spectra. It should be able to identify key biochemical changes before the tumour becomes detectable by other functional imaging methods that rely upon single markers not entirely sensitive or specific for malignant activity. MRSI is potentially well suited for screening and repeated monitoring since it entails no radiation exposure. There are, however, limitations to current applications of Magnetic Resonance Spectroscopy (MRS) and MRSI. Many of these can be directly related to reliance upon the conventional data analytical method, i.e. the Fast Fourier Transform (FFT), which has low resolution, poor signal/noise (S/N) in clinical signals, supplies only shape spectra and requires fitting, which is non-unique, so that the number of metabolites must be guessed in advance. This can lead to spurious peaks (over-fitting) and true metabolites being undetected (under-fitting). These limitations of the FFT can be circumvented by recent mathematical advances in signal processing via e.g. the Fast Pade Transform (FPT). As a high resolution, non-linear, stable parametric method, the FPT substantially improves S/N, and fulfills stringent requirements for tumour diagnostics: no post-processing fitting, provides precise numerical results for all peak parameters, and specifies the exact number of metabolites (including those that overlap) from the encoded data. We illustrate in a realistic synthesized model problem similar to MRS that the FPT can identify overlapping peaks that are entirely missed by the FFT, and we give an example from in vivo MRS of the superior resolving power of the FPT compared to FFT at short acquisition time. We also perform detailed paired and logistic regression analyses of Nuclear Magnetic Resonance (NMR) data on extracted breast specimens

  13. Prospective analysis of magnetic resonance imaging accuracy in diagnosing traumatic injuries of the posterior ligamentous complex of the thoracolumbar spine.

    Science.gov (United States)

    Pizones, Javier; Sánchez-Mariscal, Felisa; Zúñiga, Lorenzo; Álvarez, Patricia; Izquierdo, Enrique

    2013-04-20

    Prospective cohort study. To study magnetic resonance imaging (MRI) accuracy in diagnosing posterior ligamentous complex (PLC) damage, when applying the new dichotomic instability criteria in a prospective cohort of patients with vertebral fracture. Recent studies dispute MRI accuracy to diagnose PLC injuries. They analyze the complex based on 3 categories (intact/indeterminate/rupture), including the indeterminate in the ruptured group (measurement bias) in the accuracy analysis. Moreover, fractures with conservative treatment (selection bias) are not included. Both facts reduce the specificity. A recent study has proposed new criteria where posterior instability is determined with supraspinous ligament (SSL) rupture. Prospective study of patients with acute thoracolumbar fracture, using radiography and MRI (FS-T2-w/short-tau inversion-recovery sequences). 1. The integrity (ruptured/unruptured) of each isolated component of the PLC (facet capsules, interspinous ligament, SSL, and ligamentum flavum) was assessed via MRI and surgical findings. 2. PLC integrity as a whole was assessed, adopting the new dichotomic stability criteria from previous studies. In the MR images, PLC is considered ruptured when the SSL is found discontinued, and intact when not (this excludes the "indeterminate" category). In surgically treated fractures, PLC stability as a whole was assessed dynamically (ruptured/unruptured). In conservative fractures, PLC stability was assessed according to change in vertebral kyphosis measured with the local kyphotic angle at 2-year follow-up (ruptured if difference is > 5°/unruptured if difference is PLC damage. Fifty-eight vertebral fractures were studied (38 surgical, 20 conservative), of which 50% were in males; average age, 40.4 years. MRI sensitivity for injury diagnosis of each isolated PLC component varied between 92.3% (interspinous ligament) and 100% (ligamentum flavum). Specificity varied between 52% (facet capsules) and 100% (SSL). PLC

  14. Analysis and reduction of thermal magnetic noise in liquid-He dewar for sensitive low-field nuclear magnetic resonance measurements

    International Nuclear Information System (INIS)

    Hwang, S. M.; Yu, K. K.; Lee, Y. H.; Kang, C. S.; Kim, K.; Lee, S. J.

    2013-01-01

    For sensitive measurements of micro-Tesla nuclear magnetic resonance (μT-NMR) signal, a low-noise superconducting quantum interference device (SQUID) system is needed. We have fabricated a liquid He dewar for an SQUID having a large diameter for the pickup coil. The initial test of the SQUID system showed much higher low-frequency magnetic noise caused by the thermal magnetic noise of the aluminum plates used for the vapor-cooled thermal shield material. The frequency dependence of the noise spectrum showed that the noise increases with the decrease of frequency. This behavior could be explained from a two-layer model; one generating the thermal noise and the other one shielding the thermal noise by eddy-current shielding. And the eddy-current shielding effect is strongly dependent on the frequency through the skin-depth. To minimize the loop size for the fluctuating thermal noise current, we changed the thermal shield material into insulated thin Cu mesh. The magnetic noise of the SQUID system became flat down to 0.1 Hz with a white noise of 0.3 fT√ Hz, including the other noise contributions such as SQUID electronics and magnetically shielded room, etc, which is acceptable for low-noise μT-NMR experiments.

  15. Magnetic resonance. Gamma Rays in cardiology laboratories

    International Nuclear Information System (INIS)

    Lombardi, M.

    2001-01-01

    In recent years Cardiologists have shown an increasing interest on the use of Magnetic Resonance Imaging (MRI) for assessing cardiovascular diseases. The first generation of MRI equipment dedicated to cardiology is now available. The MRI Laboratory of Clinical Physiology Institute in Pisa has joined a multi-centric international project for the development of prototype of this dedicated machine and is currently involved in several subprojects such as the study of myocardial perfusion and the assessment of congenital heart diseases. An interdisciplinary group (cardiologists, software and hardware engineers, biologists, etc.) is full time involved in the development of new analysis algorithms, etc. The new concept of installing a MRI machine within clinical cardiovascular department has started to induce fruitful cooperations either in the research field or in the clinical setting [it

  16. 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.

  17. Magnetic resonance imaging of facial muscles

    International Nuclear Information System (INIS)

    Farrugia, M.E.; Bydder, G.M.; Francis, J.M.; Robson, M.D.

    2007-01-01

    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

  18. Generation of nuclear magnetic resonance images

    International Nuclear Information System (INIS)

    Beckmann, N.X.

    1986-01-01

    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.)

  19. Susceptibility effects in nuclear magnetic resonance imaging

    International Nuclear Information System (INIS)

    Ziener, Christian Herbert

    2008-01-01

    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.)

  20. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... a risk, depending on their nature and the strength of the MRI magnet. Many implanted devices will ... full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy ...

  1. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... a risk, depending on their nature and the strength of the MRI magnet. Many implanted devices will ... full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy ...

  2. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... and extremities. Tell your doctor about your child’s health problems, medications, recent surgeries and allergies. The magnetic ... the radiologist if your child has any serious health problems or has recently had surgery. Some conditions, ...

  3. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... doctor about your child’s health problems, medications, recent surgeries and allergies. The magnetic field is not harmful, ... to the heart muscle evaluate findings following cardiovascular surgery In the abdominal and pelvic region, MRI is ...

  4. Magnetic Resonance Imaging (MRI) -- Head

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    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 ...

  5. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... distort images of the facial area or brain, so you should let the radiologist know about them. ... MRI units, called short-bore systems , are designed so that the magnet does not completely surround you. ...

  6. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... distort images of the facial area or brain, so the radiologist should be aware of them. Parents ... MRI units, called short-bore systems , are designed so that the magnet does not completely surround you. ...

  7. Magnetic Resonance Imaging (MRI) -- Head

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    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 ...

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

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    Full Text Available ... interfere with the magnetic field of the MRI unit, metal and electronic items are not allowed in ... the MRI equipment look like? The traditional MRI unit is a large cylinder-shaped tube surrounded by ...

  10. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... interfere with the magnetic field of the MRI unit, metal and electronic items are not allowed in ... does the equipment look like? The traditional MRI unit is a large cylinder-shaped tube surrounded by ...

  11. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... an MRI scan, but this is rare. Tooth fillings and braces usually are not affected by the magnetic field, but they may distort images of the facial area or brain, so you should let the ...

  12. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... lodged in the eyes are particularly important. Tooth fillings and braces usually are not affected by the magnetic field, but they may distort images of the facial area or brain, so the radiologist should be ...

  13. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... traditional MRI unit is a large cylinder-shaped tube surrounded by a circular magnet. You will lie ... your skin at the site of the IV tube insertion. Some patients may sense a temporary metallic ...

  14. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... traditional MRI unit is a large cylinder-shaped tube surrounded by a circular magnet. Your child will ... skin irritation at the site of the IV tube insertion. Some patients may sense a temporary metallic ...

  15. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... conditions. MRI uses a powerful magnetic field, radio frequency pulses and a computer to produce detailed pictures ... may follow your regular daily routine and take food and medications as usual. Some MRI examinations may ...

  16. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... conditions. MRI uses a powerful magnetic field, radio frequency pulses and a computer to produce detailed pictures ... regular daily routine and have him/her take food and medications as usual. Some MRI examinations may ...

  17. Magnetic Resonance Imaging (MRI) -- Head

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    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 ...

  18. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... if your child has any implanted medical or electronic devices. Inform your doctor and the technologist prior ... magnetic field of the MRI unit, metal and electronic items are not allowed in the exam room. ...

  19. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... The magnetic field is produced by passing an electric current through wire coils in most MRI units. ... signals that are detected by the coils. The electric current does not come in contact with the ...

  20. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... The magnetic field is produced by passing an electric current through wire coils in most MRI units. ... signals that are detected by the coils. The electric current does not come in contact with the ...

  1. Magnetic Resonance Imaging (MRI) -- Head

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

  2. Magnetic Resonance Imaging (MRI) -- Head

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    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 ...

  3. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... allergies. The magnetic field is not harmful, but it may cause some medical devices to malfunction. Most ... cord is needed, MRI is useful because of its ability to see through the skull and the ...

  4. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... about pregnancy and MRI. If you have claustrophobia (fear of enclosed spaces) or anxiety, you may want ... also screened for safety in the magnetic environment. Children will be given appropriately sized earplugs or headphones ...

  5. Magnetic Resonance Imaging (MRI) -- Head

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    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 ( ...

  6. Magnetic Resonance Imaging (MRI) -- Head

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

  7. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... MRI) procedure View full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media MR Angiography (MRA) Magnetic ...

  8. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... The magnetic field is produced by passing an electric current through wire coils in most MRI units. Other coils, located in the machine and in some cases, placed around the part ...

  9. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... The magnetic field is produced by passing an electric current through wire coils in most MRI units. Other coils, located in the machine and in some cases, placed around the part ...

  10. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... fluid spaces within the brain (ventricles) causes of epilepsy (seizure) hemorrhage in selected trauma patients certain chronic ... also screened for safety in the magnetic environment. Children will be given appropriately sized earplugs or headphones ...

  11. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... two-way intercom. Many MRI centers allow a 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 ...

  12. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... your child’s health problems, medications, recent surgeries and allergies. The magnetic field is not harmful, but it ... the exam if your child has a known allergy to contrast material. Your child should wear loose, ...

  13. Magnetic resonance imaging of breast implants.

    Science.gov (United States)

    Shah, Mala; Tanna, Neil; Margolies, Laurie

    2014-12-01

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

  14. Communication patterns in the field of nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Tomov, D.; Filipov, F.; Kolev, N.

    1986-01-01

    A scientometric analysis of publications presented in four secondary information sources on the problem of nuclear magnetic resonance in physics, biomedicine and technology was carried out. A dynamic growth of the number of articles in biomedicine over 1982 to 1984 was established. Secondary publications play an important role in scientific communications as revealed by citation analysis. (author)

  15. Multimodal imaging analysis of single-photon emission computed tomography and magnetic resonance tomography for improving diagnosis of Parkinson's disease

    International Nuclear Information System (INIS)

    Barthel, H.; Georgi, P.; Slomka, P.; Dannenberg, C.; Kahn, T.

    2000-01-01

    Parkinson's disease (PD) is characterized by a degeneration of nigrostriated dopaminergic neurons, which can be imaged with 123 I-labeled 2β-carbomethoxy-3β-(4-iodophenyl) tropane ([ 123 I]β-CIT) and single-photon emission computed tomography (SPECT). However, the quality of the region of interest (ROI) technique used for quantitative analysis of SPECT data is compromised by limited anatomical information in the images. We investigated whether the diagnosis of PD can be improved by combining the use of SPECT images with morphological image data from magnetic resonance imaging (MRI)/computed tomography (CT). We examined 27 patients (8 men, 19 women; aged 55±13 years) with PD (Hoehn and Yahr stage 2.1±0.8) by high-resolution [ 123 I]β-CIT SPECT (185-200 MBq, Ceraspect camera). SPECT images were analyzed both by a unimodal technique (ROIs defined directly within the SPECT studies) and a multimodal technique (ROIs defined within individual MRI/CT studies and transferred to the corresponding interactively coregistered SPECT studies). [ 123 I]β-CIT binding ratios (cerebellum as reference), which were obtained for heads of caudate nuclei (CA), putamina (PU), and global striatal structures were compared with clinical parameters. Differences between contra- and ipsilateral (related to symptom dominance) striatal [ 123 I]β-CIT binding ratios proved to be larger in the multimodal ROI technique than in the unimodal approach (e.g., for PU: 1.2*** vs. 0.7**). Binding ratios obtained by the unimodal ROI technique were significantly correlated with those of the multimodal technique (e.g., for CA: y=0.97x+2.8; r=0.70; P com subscore (r=-0.49* vs. -0.32). These results show that the impact of [ 123 I]β-CIT SPECT for diagnosing PD is affected by the method used to analyze the SPECT images. The described multimodal approach, which is based on coregistration of SPECT and morphological imaging data, leads to improved determination of the degree of this dopaminergic disorder

  16. Magnetic resonance enterography in pediatric celiac disease.

    Science.gov (United States)

    Koc, Gonca; Doganay, Selim; Sevinc, Eylem; Deniz, Kemal; Chavhan, Govind; Gorkem, Sureyya B; Karacabey, Neslihan; Dogan, Mehmet S; Coskun, Abdulhakim; Aslan, Duran

    To assess if magnetic resonance enterography is capable of showing evidence/extent of disease in pediatric patients with biopsy-proven celiac disease by comparing with a control group, and to correlate the magnetic resonance enterography findings with anti-endomysial antibody level, which is an indicator of gluten-free dietary compliance. Thirty-one pediatric patients (mean age 11.7±3.1 years) with biopsy-proven celiac disease and 40 pediatric patients as a control group were recruited in the study. The magnetic resonance enterography images of both patients with celiac disease and those of the control group were evaluated by two pediatric radiologists in a blinded manner for the mucosal pattern, presence of wall thickening, luminal distention of the small bowel, and extra-intestinal findings. Patient charts were reviewed to note clinical features and laboratory findings. The histopathologic review of the duodenal biopsies was re-conducted. The mean duration of the disease was 5.6±1.8 years (range: 3-7.2 years). In 24 (77%) of the patients, anti-endomysial antibody levels were elevated (mean 119.2±66.6RU/mL). Magnetic resonance enterography revealed normal fold pattern in all the patients. Ten (32%) patients had enlarged mesenteric lymph nodes. Although a majority of the patients had elevated anti-endomysial antibody levels indicating poor dietary compliance, magnetic resonance enterography did not show any mucosal abnormality associated with the inability of magnetic resonance enterography to detect mild/early changes of celiac disease in children. Therefore, it may not be useful for the follow-up of pediatric celiac disease. Copyright © 2017 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

  17. Magnetic resonance imaging. Density equalizing mapping analysis of global research architecture; Magnetresonanztomographie. Eine Density-equalizing-mapping-Analyse der globalen Forschungsarchitektur

    Energy Technology Data Exchange (ETDEWEB)

    Ohlendorf, D.; Schwarze, B.; Groneberg, D.A.; Schwarzer, M. [Goethe-Universitaet Frankfurt/M, Institut fuer Arbeitsmedizin, Sozialmedizin und Umweltmedizin, Frankfurt/M (Germany)

    2015-09-15

    Despite the great medical importance, there is still no comprehensive scientometric analysis regarding the results of magnetic resonance imaging (MRI) and the development of the importance for the healthcare system. This paper evaluated and analyzed the entire research publication results on the topic of MRI for the period 1981-2007 based on scientometric methods and parameters. A scientometric analysis (database: ISI Web of Science 1981-2007, search terms MRI and magnetic resonance imaging) was performed. The following parameters were analyzed: number of publications, countries of publication, number of citations, citation rate and collaborations, using various analytical and display techniques, including density equalizing map projections. Most of the 49,122 publications on MRI could be attributed to the USA (32.5 %), which also has the most cooperative collaborations. Within Europe, Germany (10.3 %) is the country with the highest number of publications followed by the UK (9.3 %). The western industrialized nations dominate over the rest of the world in terms of scientific developments of MRI. The thematic focus of the publications lies in the fields of radiology and neuroscience. In addition to the journal Neurology most scientific articles were published in Magnetic Resonance in Medicine and Circulation. The results show that the current trend is continuing and the scientific interest in MRI is continuously increasing. (orig.) [German] Trotz der grossen medizinischen Bedeutung existiert bis heute keine umfassende szientometrische Analyse bzgl. der Forschungsergebnisse zur Magnetresonanztomographie (MRT) und der Entwicklung ihrer Bedeutung fuer das Gesundheitssystem. Im vorliegenden Beitrag soll anhand szientometrischer Methoden und Parameter das gesamte Forschungsaufkommen zum Thema MRT fuer den Zeitraum 1981-2007 evaluiert und analysiert werden. Es wurde eine szientometrische Analyse (Datenbank: ISI-Web of Science, 1981-2007; Suchterm &apos

  18. Magnetic resonance imaging of popliteal artery pathologies

    International Nuclear Information System (INIS)

    Holden, Andrew; Merrilees, Stephen; Mitchell, Nicola; Hill, Andrew

    2008-01-01

    This paper illustrates examples of popliteal artery pathologies imaged with contrast enhanced magnetic resonance angiography (CE-MRA) and magnetic resonance imaging (MRI) at a single tertiary referral centre. Popliteal artery pathologies were identified in 1710 patients referred over a 6-year period with symptoms suggesting lower limb arterial occlusive disease. Common pathologies such as atherosclerotic occlusive disease, thromboemboli and aneurysm disease are discussed as well as unusual pathologies such as cystic adventitial disease, mycotic aneurysm and arterial entrapment. The combination of CE-MRA and the excellent soft tissue resolution of MRI allow detailed evaluation of arterial and peri-arterial pathologies, and facilitate appropriate management decisions

  19. Magnetic resonance imaging of popliteal artery pathologies

    Energy Technology Data Exchange (ETDEWEB)

    Holden, Andrew [Department of Radiology, Auckland City Hospital, Park Road, Grafton, Auckland 9 (New Zealand)], E-mail: andrewh@adhb.govt.nz; Merrilees, Stephen [Department of Radiology, Auckland City Hospital, Park Road, Grafton, Auckland 9 (New Zealand)], E-mail: smerrilees@adhb.govt.nz; Mitchell, Nicola [Department of Radiology, Auckland City Hospital, Park Road, Grafton, Auckland 9 (New Zealand)], E-mail: nmit010@ec.auckland.ac.nz; Hill, Andrew [Department of Vascular Surgery, Auckland City Hospital, Park Road, Grafton, Auckland 9 (New Zealand)], E-mail: ahill@adhb.govt.nz

    2008-07-15

    This paper illustrates examples of popliteal artery pathologies imaged with contrast enhanced magnetic resonance angiography (CE-MRA) and magnetic resonance imaging (MRI) at a single tertiary referral centre. Popliteal artery pathologies were identified in 1710 patients referred over a 6-year period with symptoms suggesting lower limb arterial occlusive disease. Common pathologies such as atherosclerotic occlusive disease, thromboemboli and aneurysm disease are discussed as well as unusual pathologies such as cystic adventitial disease, mycotic aneurysm and arterial entrapment. The combination of CE-MRA and the excellent soft tissue resolution of MRI allow detailed evaluation of arterial and peri-arterial pathologies, and facilitate appropriate management decisions.

  20. Chromatographic and spectroscopic analysis of heavy crude oil mixtures with emphasis in nuclear magnetic resonance spectroscopy: A review

    International Nuclear Information System (INIS)

    Silva, Sandra L.; Silva, Artur M.S.; Ribeiro, Jorge C.; Martins, Fernando G.; Da Silva, Francisco A.; Silva, Carlos M.

    2011-01-01

    Graphical abstract: The chromatographic and spectroscopic techniques used to characterize heavy crude oils, although more focused in the nuclear magnetic resonance spectroscopy as the technique of choice, due to its capability to provide great information on the chemical nature of individual types of proton and carbon atoms in different and complex mixtures of crude oils are described. This review is based on 65 references and describes in a critical and interpretative ways the advantages of the NMR spectroscopy as a main technique to be used in crude oil refining industries that want to characterize crude oil fractions and the obtained refined products. Highlights: ► Chromatogrfaphic and spectroscopic techniques used to characterize heavy crude oils have been reviewed. ► This review describes in a critical and interpretative ways the advantages of the NMR spectroscopy as a main technique to be used in crude oil refining industries. ► The progress in the interpretation of the NMR spectra and of different multivariate data analyses and their potential in the identification and characterization of hydrocarbons and their physical and chemical properties have also been reviewed. - Abstract: The state of the art in the characterization of heavy crude oil mixtures is presented. This characterization can be done by different techniques, such as gas chromatography (GC), high performance liquid chromatography (HPLC), thin layer chromatography (TLC), infrared spectroscopy (IR), Raman spectroscopy, nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). Nuclear magnetic resonance spectroscopy is the technique of choice due to its capability to provide information on the chemical nature of individual types of hydrogen and carbon atoms in different and complex mixtures of crude oils. The progress made in the interpretation of the NMR spectra with the development of new NMR techniques and different multivariate data analyses could give relevant

  1. Correlation analysis of expressions of PTEN and p53 with the value obtained by magnetic resonance spectroscopy and apparent diffusion coefficient in the tumor and the tumor-adjacent area in magnetic resonance imaging for glioblastoma.

    Science.gov (United States)

    Li, Yunyun; Ji, Feng; Jiang, Yuzhi; Zhao, Ting; Xu, Chongfu

    2018-01-01

    To explore the correlation of the expression levels of phosphate and tension homology deleted on chromosome ten (PTEN) and p53 of glioblastoma multiforme (GBM) with the value obtained by magnetic resonance spectroscopy (MRS) and apparent diffusion coefficient (ADC) in the tumor and the tumor-adjacent area in magnetic resonance imaging (MRI). A total of 38 patients were operated for GBM. All the patients had received diffusion-weighted imaging (DWI) and MRS prior to surgery. ADC of water molecules and values of metabolite indexes of MRS, including n-acetyl aspartate (NAA), choline (Cho) and creatine (Cr), were recorded, and the ratios of Cho/NAA, Cho/Cr and NAA/Cr were calculated. Hematoxylin-eosin (H&E) staining was done to examine the morphology of tumor and of tumor-adjacent tissues; immunohistochemistry (IHC) was performed to examine the expressions of PTEN and p53 in the tumor and the tumor-adjacent area. Finally, the correlations of the expressions of PTEN and p53 with ADC, Cho/NAA, Cho/Cr and NAA/Cr of the tumor and the tumor-adjacent area were analyzed. H&E staining showed that GBM tissues had disordered morphology, different sizes of cells, large cell nuclei and significant cell heterogeneity. IHC indicated that the expression level of p53 protein in the tumor was significantly higher than in the tumor-adjacent tissues (pCorrelation analysis indicated that PTEN levels in the tumor and the tumor-adjacent area were positively correlated with ADC in the corresponding area, while p53 in the tumor and the tumor-adjacent area was negatively correlated with ADC in the corresponding area. Cho/NAA and Cho/Cr in the tumor were positively correlated with p53 in the tumor, but negatively correlated with PTEN in the tumor. However, NAA/Cr of the tumor was irrelevant to the levels of PTEN and p53. The test results of DWI and MRS of patients with GBM can accurately reflect the inactivation or mutation of PTEN and p53.

  2. Magnetic elliptical polarization of Schumann resonances

    International Nuclear Information System (INIS)

    Sentman, D.D.

    1987-01-01

    Measurements of orthogonal, horizontal components of the magnetic field in the ELF range obtained during September 1985 show that the Schumann resonance eigenfrequencies determined separately for the north-south and east-west magnetic components differ by as much as 0.5 Hz, suggesting that the underlying magnetic signal is not linearly polarized at such times. The high degree of magnetic ellipticity found suggests that the side multiplets of the Schumann resonances corresponding to azimuthally inhomogeneous normal modes are strongly excited in the highly asymmetric earth-ionosphere cavity. The dominant sense of polarization over the measurement passband is found to be right-handed during local daylight hours, and to be left-handed during local nighttime hours. 16 references

  3. Differentiation of Organically and Conventionally Grown Tomatoes by Chemometric Analysis of Combined Data from Proton Nuclear Magnetic Resonance and Mid-infrared Spectroscopy and Stable Isotope Analysis.

    Science.gov (United States)

    Hohmann, Monika; Monakhova, Yulia; Erich, Sarah; Christoph, Norbert; Wachter, Helmut; Holzgrabe, Ulrike

    2015-11-04

    Because the basic suitability of proton nuclear magnetic resonance spectroscopy ((1)H NMR) to differentiate organic versus conventional tomatoes was recently proven, the approach to optimize (1)H NMR classification models (comprising overall 205 authentic tomato samples) by including additional data of isotope ratio mass spectrometry (IRMS, δ(13)C, δ(15)N, and δ(18)O) and mid-infrared (MIR) spectroscopy was assessed. Both individual and combined analytical methods ((1)H NMR + MIR, (1)H NMR + IRMS, MIR + IRMS, and (1)H NMR + MIR + IRMS) were examined using principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), linear discriminant analysis (LDA), and common components and specific weight analysis (ComDim). With regard to classification abilities, fused data of (1)H NMR + MIR + IRMS yielded better validation results (ranging between 95.0 and 100.0%) than individual methods ((1)H NMR, 91.3-100%; MIR, 75.6-91.7%), suggesting that the combined examination of analytical profiles enhances authentication of organically produced tomatoes.

  4. Accuracy of magnetic resonance studies in the detection of chondral and labral lesions in femoroacetabular impingement: systematic review and meta-analysis.

    Science.gov (United States)

    Saied, A M; Redant, C; El-Batouty, M; El-Lakkany, M R; El-Adl, W A; Anthonissen, J; Verdonk, R; Audenaert, E A

    2017-02-16

    Several types of Magnetic resonance imaging (MRI) are commonly used in imaging of femoroacetabular impingement (FAI), however till now there are no clear protocols and recommendations for each type. The aim of this meta-analysis is to detect the accuracy of conventional magnetic resonance imaging (cMRI), direct magnetic resonance arthrography (dMRA) and indirect magnetic resonance arthrography (iMRA) in the diagnosis of chondral and labral lesions in femoroacetabular impingement (FAI). A literature search was finalized on the 17th of May 2016 to collect all studies identifying the accuracy of cMRI, dMRA and iMRA in diagnosing chondral and labral lesions associated with FAI using surgical results (arthroscopic or open) as a reference test. Pooled sensitivity and specificity with 95% confidence intervals using a random-effects meta-analysis for MRI, dMRA and iMRA were calculated also area under receiver operating characteristic (ROC) curve (AUC) was retrieved whenever possible where AUC is equivocal to diagnostic accuracy. The search yielded 192 publications which were reviewed according inclusion and exclusion criteria then 21 studies fulfilled the eligibility criteria for the qualitative analysis with a total number of 828 cases, lastly 12 studies were included in the quantitative meta-analysis. Meta-analysis showed that as regard labral lesions the pooled sensitivity, specificity and AUC for cMRI were 0.864, 0.833 and 0.88 and for dMRA were 0.91, 0.58 and 0.92. While in chondral lesions the pooled sensitivity, specificity and AUC for cMRI were 0.76, 0.72 and 0.75 and for dMRA were 0.75, 0.79 and 0.83, while for iMRA were sensitivity of 0.722 and specificity of 0.917. The present meta-analysis showed that the diagnostic test accuracy was superior for dMRA when compared with cMRI for detection of labral and chondral lesions. The diagnostic test accuracy was superior for labral lesions when compared with chondral lesions in both cMRI and dMRA. Promising results are

  5. Late gadolinium uptake demonstrated with magnetic resonance in patients where automated PERFIT analysis of myocardial SPECT suggests irreversible perfusion defect

    International Nuclear Information System (INIS)

    Rosendahl, Lene; Blomstrand, Peter; Ohlsson, Jan L; Björklund, Per-Gunnar; Ahlander, Britt-Marie; Starck, Sven-Åke; Engvall, Jan E

    2008-01-01

    Myocardial perfusion single photon emission computed tomography (MPS) is frequently used as the reference method for the determination of myocardial infarct size. PERFIT ® is a software utilizing a three-dimensional gender specific, averaged heart model for the automatic evaluation of myocardial perfusion. The purpose of this study was to compare the perfusion defect size on MPS, assessed with PERFIT, with the hyperenhanced volume assessed by late gadolinium enhancement magnetic resonance imaging (LGE) and to relate their effect on the wall motion score index (WMSI) assessed with cine magnetic resonance imaging (cine-MRI) and echocardiography (echo). LGE was performed in 40 patients where clinical MPS showed an irreversible uptake reduction suggesting a myocardial scar. Infarct volume, extent and major coronary supply were compared between MPS and LGE as well as the relationship between infarct size from both methods and WMSI. MPS showed a slightly larger infarct volume than LGE (MPS 29.6 ± 23.2 ml, LGE 22.1 ± 16.9 ml, p = 0.01), while no significant difference was found in infarct extent (MPS 11.7 ± 9.4%, LGE 13.0 ± 9.6%). The correlation coefficients between methods in respect to infarct size and infarct extent were 0.71 and 0.63 respectively. WMSI determined with cine-MRI correlated moderately with infarct volume and infarct extent (cine-MRI vs MPS volume r = 0.71, extent r = 0.71, cine-MRI vs LGE volume r = 0.62, extent r = 0.60). Similar results were achieved when wall motion was determined with echo. Both MPS and LGE showed the same major coronary supply to the infarct area in a majority of patients, Kappa = 0.84. MPS and LGE agree moderately in the determination of infarct size in both absolute and relative terms, although infarct volume is slightly larger with MPS. The correlation between WMSI and infarct size is moderate

  6. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... ill effects on pregnant women or their unborn babies. However, because the unborn baby will be in a strong magnetic field, pregnant ... intravenous contrast indicate mothers should not breastfeed their babies for 24-48 hours after contrast medium is ...

  7. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... epilepsy (seizure) hemorrhage in selected trauma patients certain chronic conditions, such as multiple sclerosis disorders of the ... a very small chance of irritation of your skin at the site of the IV tube insertion. Some ... Images related to Magnetic ...

  8. Children's (Pediatric) Magnetic Resonance Imaging

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    Full Text Available ... More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic ... patient to have an allergy to a gadolinium-based contrast agent used for MRI than the iodine- ...

  9. 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 during the exam. MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ...

  10. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... which they come. The MR scanner captures this energy and creates a picture of the tissues scanned based on this information. The magnetic field is produced by passing an electric current through wire coils in most MRI units. ...

  11. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... which they come. The MR scanner captures this energy and creates a picture of the tissues scanned based on this information. The magnetic field is produced by passing an electric current through wire coils in most MRI units. ...

  12. Nuclear magnetic resonance (NMR) tomography

    International Nuclear Information System (INIS)

    Skalpe, I.O.

    1984-01-01

    A brief survey of the working principle of the NMR technique in diagnostical medicine is given. Its clinical usefulness for locating tumors, diagnosing various other diseases, such as some mental illnesses and multiple sclerosis, and its possibilities for studying biochemical processes in vivo are mentioned. The price of NMR image scanners and the problems of the strong magnetic field around the machines are mentioned

  13. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us ... MRI equipment look like? How does the procedure work? How is the ... use to diagnose medical conditions. MRI uses a powerful magnetic field, radio frequency ...

  14. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us ... the equipment look like? How does the procedure work? How is the ... use to diagnose medical conditions. MRI uses a powerful magnetic field, radio frequency ...

  15. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... to see, hear and speak with your child at all times using a two-way intercom. Many MRI centers allow a parent to stay in the room as long as they are also screened for safety in the magnetic environment. Children will be given ...

  16. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... able to see, hear and speak with you at all times using a two-way intercom. Many 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 ...

  17. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... the head uses a powerful magnetic field, radio waves and a computer to produce detailed pictures of the brain and other cranial structures that are clearer and more detailed than other imaging methods. This exam does not use ionizing radiation and may require an injection of a ...

  18. Analysis of SAR distribution in human head of antenna used in wireless power transform based on magnetic resonance.

    Science.gov (United States)

    Gong, Feixiang; Wei, Zhiqiang; Cong, Yanping; Chi, Haokun; Yin, Bo; Sun, Mingui

    2017-07-20

    In this paper, a novel wireless power transfer antenna system was designed for human head implantable devices. The antenna system used the structure of three plates and four coils and operated at low frequencies to transfer power via near field. In order to verify the electromagnetic radiation safety on the human head, the electromagnetic intensity and specific absorption rate (SAR) were studied by finite-difference-time-domain (FDTD) method. A three-layer model of human head including skin, bone and brain tissues was constructed. The transmitting and receiving antenna were set outside and inside the model. The local and average SAR were simulated at the resonance frequency of 18.67 MHz in two situations, in one scenario both transmitting and receiving coil worked, while in the other scenario only the transmitting coil worked. The results showed that the maximum of 10 g SAR average value of human thoracic were 0.142 W/kg and 0.148 W/kg, respectively, both were lower than the international safety standards for human body of the ICNIRP and FCC, which verified the safety of the human body in wireless power transmission based on magnetic coupling resonance.

  19. Magnetic resonance investigation of magnetic-labeled baker's yeast cells

    International Nuclear Information System (INIS)

    Godoy Morais, J.P.M.; Azevedo, R.B.; Silva, L.P.; Lacava, Z.G.M.; Bao, S.N.; Silva, O.; Pelegrini, F.; Gansau, C.; Buske, N.; Safarik, I.; Safarikova, M.; Morais, P.C.

    2004-01-01

    In this study, the interaction of DMSA-coated magnetite nanoparticles (5 and 10 nm core-size) with Saccharomyces cerevisae was investigated using magnetic resonance (MR) and transmission electron microscopy (TEM). The TEM micrographs revealed magnetite nanoparticles attached externally to the cell wall. The MR data support the strong interaction among the nanoparticles supported by the cells. A remarkable shift in the resonance field was used as signature of particle attachment to the cell wall

  20. Analysis of factors causing signal loss in the measurement of lung tissue water by nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Fukuzaki, Minoru; Shioya, Sumie; Haida, Munetaka

    1997-01-01

    The water content of lung, brain, and muscle tissue was measured by nuclear magnetic resonance (NMR) and compared with gravimetric determinations. The NMR signal intensity of water was measured by a single 90 degree pulse and by a spin-echo sequence. The absolute water content was determined by the difference in the sample's weight before and after desiccation. The NMR detectable water in each tissue was expressed as a percentage of the signal intensity for an equal weight of distilled water. Using the single pulse measurement, 67% of the gravimetrically-measured water was detected in collapsed lung samples (consisting of about 47% retained air), in contrast to 96% for brain and 98% for muscle. For degassed lung samples, the NMR detectability of water increased to 87% with the single pulse measurement and to 90% with the spin-echo measurement, but the values remained significantly less than those of brain or muscle. Factors that caused the NMR signal loss of 33% in collapsed lung samples were: air-tissue interfaces (20%), microscopic field inhomogeneity (3%), and a water component with an extremely short magnetization decay time constant (10%). (author)

  1. resonant inverter supplied interior permanent magnet (ipm)

    African Journals Online (AJOL)

    user

    [5] Zhenyue Hong, “DC-voltage link resonant inverters”, Department of Electrical and. Electronic Engineering University of. Canterbury, New Zealand. [6] Kalyan Kumar Halder, Naruttam Kumar Roy and B.C. Ghosh, “Position Sensorless. Control for an Interior Permanent Magnet. Synchronous Motor SVM Drive with ANN.

  2. Magnetic resonance imaging in radiotherapy treatment planning

    NARCIS (Netherlands)

    Moerland, Marinus Adriaan

    1996-01-01

    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

  3. Pharyngeal branchial cyst: magnetic resonance findings

    Energy Technology Data Exchange (ETDEWEB)

    Cerezal, L.; Canga, A. [Department of Radiology of the ' Santa Cruz' Hospital Liencres, Cantabria (Spain); Morales, C. [Department of Otorhinolaryngology of the ' Sierrallana' Hospital Torrelavega, Cantabria (Spain); Abascal, F.; Usamentiaga, E.; Bustamante, M. [Department of Radiology of the University Hospital ' Marques de Valdecilla' , Av. de Valdecilla s/n Santander 39008 (Spain); Olcinas, O. [Department of Pathology of the University Hospital ' Marques de Valdecilla' , Av. de Valdecilla s/n Santander 39008 (Spain)

    1998-11-01

    An unusual case of pharyngeal cyst in a 25-year-old man studied by Magnetic Resonance (MR) is described. Anatomic location and pathological findings indicated the second branchial pouch origin. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  4. Pharyngeal branchial cyst: magnetic resonance findings

    International Nuclear Information System (INIS)

    Cerezal, L.; Canga, A.; Morales, C.; Abascal, F.; Usamentiaga, E.; Bustamante, M.; Olcinas, O.

    1998-01-01

    An unusual case of pharyngeal cyst in a 25-year-old man studied by Magnetic Resonance (MR) is described. Anatomic location and pathological findings indicated the second branchial pouch origin. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  5. Magnetic resonance angiography in meningovascular syphilis

    Energy Technology Data Exchange (ETDEWEB)

    Gallego, J [Servicio de Neurologia, Hospital de Navarra and Pamplona Univ. Hospital (Spain); Soriano, G [Servicio de Neurologia, Hospital de Navarra and Pamplona Univ. Hospital (Spain); Zubieta, J L [Servicio de Neuroradiologia, Hospital de Navarra and Pamplona Univ. Hospital (Spain); Delgado, G [Servicio de Neurologia, Hospital de Navarra and Pamplona Univ. Hospital (Spain); Villanueva, J A [Servicio de Neurologia, Hospital de Navarra and Pamplona Univ. Hospital (Spain)

    1994-04-01

    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.)

  6. Cryogenic Preamplifiers for Magnetic Resonance Imaging

    DEFF Research Database (Denmark)

    Johansen, Daniel H.; Sanchez-Heredia, Juan D.; Petersen, Jan R.

    2018-01-01

    Pursuing the ultimate limit of detection in magnetic resonance imaging (MRI) requires cryogenics to decrease the thermal noise of the electronic circuits. As cryogenic coils for MRI are slowly emerging cryogenic preamplifiers are required to fully exploit their potential. A cryogenic preamplifier...

  7. 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...

  8. Magnetic resonance imaging of xanthomatous meningioma

    International Nuclear Information System (INIS)

    Katayama, Y.; Tsubokawa, T.; Tanaka, A.; Koshinaga, M.; Nemoto, N.

    1993-01-01

    A case of meningioma with extensive xanthomatous metaplasia occurring in the left frontal convexity of a 37-year-old woman is reported. The tumour was demonstrated as a hypodense mass with minimal enhancement on CT. Our findings suggest that magnetic resonance imaging may provide a clue to the diagnosis of meningiomas with extensive xanthomatous metaplasia when CT is less specific. (orig.)

  9. Vascular anatomy in angiography for magnetic resonance

    International Nuclear Information System (INIS)

    Charry Lopez, Marco Luciano; Rivera Gomez, Juan Enrique

    1998-01-01

    A review of basic anatomical concepts and main variants, as well as some anatomical anomalies of the central nervous system vascularity, these concepts are considered essential for the interpretation of magnetic resonance angiography with time-of-flight (TOF) and phase-contrast (PC) methods

  10. Magnetic resonance imaging in obstetric diagnosis.

    Science.gov (United States)

    Weinreb, J C; Lowe, T W; Santos-Ramos, R; Cunningham, F G; Parkey, R

    1985-01-01

    Five patients with abnormal pregnancies were examined with ultrasound (US) and magnetic resonance imaging (MR). Three had a malformed fetus, 1 had a molar pregnancy, and 1 had an ovarian mass. Both maternal and fetal structures were clearly shown, although fetal motion may have resulted in image degradation in some cases. The authors suggest that MR may be useful in obstetric diagnosis.

  11. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... talk with you about magnetic resonance angiography, or as it’s commonly known, MRA. MRA is a noninvasive ... possibility that you’re pregnant tell your doctor as well. On the day of your exam, it’s ...

  12. Magnetic resonance studies of solid polymers

    International Nuclear Information System (INIS)

    Lenk, R.

    1969-01-01

    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) [fr

  13. Appropriateness of computed tomography and magnetic resonance ...

    African Journals Online (AJOL)

    Introduction. Computed tomography (CT) and magnetic resonance imaging (MRI) are an essential part of modern healthcare. Marked increases in clinical demand for these imaging modalities are straining healthcare expenditure and threatening health system sustainability. The number of CT and MRI scans requested in ...

  14. Magnetic resonance imaging of the knee

    International Nuclear Information System (INIS)

    Nederveen, D.; Bakker, C.J.G.; Scholten, F.G.; Feldberg, N.A.M.; Postma, J.H.; Vis, H. van der

    1989-01-01

    Sixteen patients suspected of having meniscal lesions, were examined bt magnetic resonance (MR) and arthroscopy, MR and arthroscopy corelate well for meniscal and cruciate ligament lesions. Damage of the articular cartilage was, however, not detected by MR (author). 15 refs.; 4 figs.; 1 tab

  15. Intralabyrinthine schwannoma shown by magnetic resonance imaging

    International Nuclear Information System (INIS)

    Saeed, S.R.; Birzgalis, A.R.; Ramsden, R.T.

    1994-01-01

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

  16. Magnetic resonance imaging of semicircular canals.

    Science.gov (United States)

    Sbarbati, A; Leclercq, F; Zancanaro, C; Antonakis, K

    1992-01-01

    The present paper reports the results of the first investigation of the semicircular canals in a living, small animal by means of high spatial resolution magnetic resonance imaging. This procedure is noninvasive and allows identification of the endolymphatic and perilymphatic spaces yielding a morphology quite consistent with direct anatomical examination. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:1506290

  17. Quantitative dosing by nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Solomon, I.

    1958-01-01

    The measurement of the absolute concentration of a heavy water reference containing approximately 99.8 per cent of D 2 O has been performed, by an original magnetic resonance method ('Adiabatic fast passage method') with a precision of 5.10 -5 on the D 2 O concentration. (author) [fr

  18. Magnetic resonance angiography in meningovascular syphilis

    International Nuclear Information System (INIS)

    Gallego, J.; Soriano, G.; Zubieta, J.L.; Delgado, G.; Villanueva, J.A.

    1994-01-01

    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.)

  19. Nonlinear nuclear magnetic resonance in ferromagnets

    International Nuclear Information System (INIS)

    Nurgaliev, T.

    1988-01-01

    The properties of nonlinear nuclear magnetic resonance (NMR) have been studied theoretically by taking into account the interaction between NMR and FMR in the ferromagnets. The Landau-Lifshitz-Bloch equations, describing the electron and nuclear magnetization behaviour in ferromagnets are presented in an integral form for a weakly excited electronic system. The stationary solution of these equations has been analysed in the case of equal NMR and FMR frequencies: the criteria for the appearance of two stable dynamic states is found and the high-frequency magnetic susceptibility for these systems is investigated. 2 figs., 8 refs

  20. 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.

  1. Magnetic Barkhausen noise measurement by resonant coil method

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-09-15

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

  2. Fingerprinting analysis of Rhizoma chuanxiong of commercial types using 1H nuclear magnetic resonance spectroscopy and high performance liquid chromatography method.

    Science.gov (United States)

    Qin, Hai-Lin; Deng, An-Jun; Du, Guan-Hua; Wang, Peng; Zhang, Jin-Lan; Li, Zhi-Hong

    2009-06-01

    The (1)H nuclear magnetic resonance ((1)H NMR) fingerprints of fractionated non-polar extracts (control substance for a plant drug (CSPD) A) from Rhizoma chuanxiong, the rhizomes of Ligusticum chuanxiong Hort., of seven specimens from different sources were measured on Fourier Transform (FT)-NMR spectrometer and assigned by comparing them with the (1)H NMR spectra of the isolated pure compounds. The (1)H NMR fingerprints showed exclusively characteristic resonance signals of the major special constituents of the plant. Although the differences in the relative intensity of the (1)H NMR signals due to a discrepancy in the ratio of the major constituents among these samples could be confirmed by high performance liquid chromatography analysis, the general features of the (1)H NMR fingerprint established for an authentic sample of the rhizomes of L. chuanxiong exhibited exclusive data from those special compounds and can be used for authenticating L. Chuanxiong species.

  3. Fingerprinting Analysis of Rhizoma Chuanxiong of Commercial Types using 1H Nuclear Magnetic Resonance Spectroscopy and High Performance Liquid Chromatography Method

    Institute of Scientific and Technical Information of China (English)

    Hai-Lin Qin; An-Jun Deng; Guan-Hua Du; Peng Wang; Jin-Lan Zhang; Zhi-Hong Li

    2009-01-01

    The 1H nuclear magnetic resonance (1H NMR) fingerprints of fractionated non-polar extracts (control substance for a plant drug (CSPD) A) from Rhizoma chuanxiong, the rhizomes of Ligusticum chuanxiong Hort., of seven specimens from different sources were measured on Fourier Transform (FT)-NMR spectrometer and assigned by comparing them with the 1H NMR spectra of the isolated pure compounds. The 1H NMR fingerprints showed exclusively characteristic resonance signals of the major special constituents of the plant. Although the differences in the relative intensity of the 1H NMR signals due to a discrepancy in the ratio of the major constituents among these samples could be confirmed by high performance liquid chromatography analysis, the general features of the 1H NMR fingerprint established for an authentic sample of the rhizomes of L. chuanxiong exhibited exclusive data from those special compounds and can be used for authenticating L. Chuanxiong species.

  4. Magnetic resonance imaging of infectious myositis

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-09-01

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

  5. Magnetic resonance imaging of infectious myositis

    International Nuclear Information System (INIS)

    Yun, Ji Young; Kim, Jee Young; Kim, Sang Heum; Jung, Youn Ju; Cha, Eun Suk; Park, Joung Mi; Park, Young Ha

    1998-01-01

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

  6. Magnetic resonance: safety measures and biological effects

    International Nuclear Information System (INIS)

    Gordillo, I.; Lafuente, J.; Fernandez, C.; Barbero, M.J.; Cascon, E.

    1997-01-01

    The biological effects of electromagnetic fields is currently a subject of great controversy. For this reason, magnetic resonance imaging (MRI) and spectroscopy are constantly under investigation. The source of the risk in MRI is associated with the three types of electromagnetic radiation to which the patient is exposed: the static magnetic field, variable (gradient) magnetic fields and radiofrequency fields. Each is capable of producing significant biological effects when employed at sufficient intensity. Patients exposed to risk sources are those situated within the lines of force of the magnetic field, ellipsoid lines that are arranged around the magnet, representing the strength of the surrounding field. To date, at the intensity normally utilized in MRI(<2T) and respecting the field limit recommendations established by the US Food and Drug Administration (FDA) for clinical use of this technique no adverse secondary biological effects have been reported. The known biological effects and other possible secondary effects are reviewed, and the recommended safety measures are discussed. (Author)

  7. Magnetic resonance imaging of aneurysmal subarachnoid hemorrhage

    International Nuclear Information System (INIS)

    Ogawa, Toshihide; Shimosegawa, Eku; Inugami, Atsushi; Shishido, Fumio; Fujita, Hideaki; Ito, Hiroshi; Uemura, Kazuo; Yasui, Nobuyuki

    1991-01-01

    Magnetic resonance imaging of subarachnoid hemorrhage (SAH) due to aneurysm rupture was evaluated in relation to CT findings in nine patients. Six patients were studied within 3 days and the other three patients were studied 4 to 6 days from the ictus of SAH using a 0.5 Tesla superconducting unit. In all of the patients, hematoma in the subarachnoid space and ventricles was demonstrated by the proton density-weighted spin echo sequence, which showed that bloody cerebrospinal fluid (CSF) had a higher signal intensity than brain tissue or normal CSF. Magnetic resonance imaging was more sensitive in detecting SAH and more informative as to the site of the ruptured aneurysm than CT. Despite some limitations in applying it to patients with acute SAH, magnetic resonace imaging has clear advantages in the diagnosis of SAH. (author)

  8. The market for magnetic resonance spectroscopy

    International Nuclear Information System (INIS)

    Carlson, L.

    1990-01-01

    The medical market is, at present, the most dominant market for low T c superconductors. Indeed, without magnetic resonance imaging (MRI), there would hardly be a low T c superconductor market at all. According to the author, any development that can expand the medical market for MRI machines would be a welcome one. This paper reports how the recent advances in magnetic resonance spectroscopy (MRS) are such a development. While the principle of MRS has bee around as long as MRI, only recently have advances in technique, computer programming and magnet technology allowed MRS to advance to a point where it may become an important technology-one that could increase the medical market for superconductors. The author discussed how MRS can be used to analyze oil core samples for their oil content, oil/water ratios, how the oil is bound and how to extract it

  9. Magnetic resonance imaging of aneurysmal subarachnoid hemorrhage

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Toshihide; Shimosegawa, Eku; Inugami, Atsushi; Shishido, Fumio; Fujita, Hideaki; Ito, Hiroshi; Uemura, Kazuo; Yasui, Nobuyuki (Research Inst. of Brain and Blood Vessels, Akita (Japan))

    1991-11-01

    Magnetic resonance imaging of subarachnoid hemorrhage (SAH) due to aneurysm rupture was evaluated in relation to CT findings in nine patients. Six patients were studied within 3 days and the other three patients were studied 4 to 6 days from the ictus of SAH using a 0.5 Tesla superconducting unit. In all of the patients, hematoma in the subarachnoid space and ventricles was demonstrated by the proton density-weighted spin echo sequence, which showed that bloody cerebrospinal fluid (CSF) had a higher signal intensity than brain tissue or normal CSF. Magnetic resonance imaging was more sensitive in detecting SAH and more informative as to the site of the ruptured aneurysm than CT. Despite some limitations in applying it to patients with acute SAH, magnetic resonace imaging has clear advantages in the diagnosis of SAH. (author).

  10. Transcranial magnetic stimulation assisted by neuronavigation of magnetic resonance images

    Science.gov (United States)

    Viesca, N. Angeline; Alcauter, S. Sarael; Barrios, A. Fernando; González, O. Jorge J.; Márquez, F. Jorge A.

    2012-10-01

    Technological advance has improved the way scientists and doctors can learn about the brain and treat different disorders. A non-invasive method used for this is Transcranial Magnetic Stimulation (TMS) based on neuron excitation by electromagnetic induction. Combining this method with functional Magnetic Resonance Images (fMRI), it is intended to improve the localization technique of cortical brain structures by designing an extracranial localization system, based on Alcauter et al. work.

  11. Magnetic resonance imaging in otolaryngology

    International Nuclear Information System (INIS)

    Gradzki, J.; Paprzycki, W.

    1993-01-01

    In the paper authors describe fundamental physical properties of a phenomenon of the radio-frequency excitation and relaxation of nuclei ordered in a strong magnetic field and the usefulness of MRI in medical diagnostic procedures. Basic interpretations principles of MR imaging due to signal intensity differences between organs and tissues in T 1 - and T 2 - weighted sequences and proton density are presented. Both, literature review and experience of authors suggest application of MRI in otolaryngology, it is illustrated by a lot of examples. The MR imaging studies were compared with results obtained from CT in otolaryngology field. (author)

  12. Magnetic Resonance Imaging (MRI): Lumbar Spine (For Parents)

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Magnetic Resonance Imaging (MRI): Lumbar Spine KidsHealth / For Parents / Magnetic Resonance Imaging (MRI): Lumbar Spine What's in this article? ...

  13. Utility of magnetic resonance imaging-based finite element analysis for the biomechanical stress analysis of hemorrhagic and non-hemorrhagic carotid plaques

    International Nuclear Information System (INIS)

    Sadat, U.; Teng, Z.; Young, V.E.; Li, Z.Y.; Gillard, J.H.

    2011-01-01

    Biomechanical stress analysis has been used for plaque vulnerability assessment. The presence of plaque hemorrhage (PH) is a feature of plaque vulnerability and is associated with thromboembolic ischemic events. The purpose of the present study was to use finite element analysis (FEA) to compare the stress profiles of hemorrhagic and non-hemorrhagic profiles. Forty-five consecutive patients who had suffered a cerebrovascular ischemic event with an underlying carotid artery disease underwent high-resolution magnetic resonance imaging (MRI) of their symptomatic carotid artery in a 1.5-T MRI system. Axial images were manually segmented for various plaque components and used for FEA. Maximum critical stress (M-Cstress SL ) for each slice was determined. Within a plaque, the maximum M-Cstress SL for each slice of a plaque was selected to represent the maximum critical stress of that plaque (M-Cstress PL ) and used to compare hemorrhagic and non-hemorrhagic plaques. A total of 62% of plaques had hemorrhage. It was observed that plaques with hemorrhage had significantly higher stress (M-Cstress PL ) than plaques without PH (median [interquartile range]: 315kPa [247-434] vs. 200kPa [171-282], P=0.003). Hemorrhagic plaques have higher biomechanical stresses than non-hemorrhagic plaques. MRI-based FEA seems to have the potential to assess plaque vulnerability. (author)

  14. 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.

  15. Observer variation factor on advanced method for accurate, robust, and efficient spectral fitting of java based magnetic resonance user interface for MRS data analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Suk Jun [Dept. of Biomedical Laboratory Science, College of Health Science, Cheongju University, Cheongju (Korea, Republic of); Yu, Seung Man [Dept. of Radiological Science, College of Health Science, Gimcheon University, Gimcheon (Korea, Republic of)

    2016-06-15

    The purpose of this study was examined the measurement error factor on AMARES of jMRUI method for magnetic resonance spectroscopy (MRS) quantitative analysis by skilled and unskilled observer method and identified the reason of independent observers. The Point-resolved spectroscopy sequence was used to acquired magnetic resonance spectroscopy data of 10 weeks male Sprague-Dawley rat liver. The methylene protons ((-CH2-)n) of 1.3 ppm and water proton (H2O) of 4.7 ppm ratio was calculated by LCModel software for using the reference data. The seven unskilled observers were calculated total lipid (methylene/water) using the jMRUI AMARES technique twice every 1 week, and we conducted interclass correlation coefficient (ICC) statistical analysis by SPSS software. The inter-observer reliability (ICC) of Cronbach's alpha value was less than 0.1. The average value of seven observer's total lipid (0.096±0.038) was 50% higher than LCModel reference value. The jMRUI AMARES analysis method is need to minimize the presence of the residual metabolite by identified metabolite MRS profile in order to obtain the same results as the LCModel.

  16. Musculoskeletal applications of magnetic resonance imaging: Council on Scientific Affairs

    International Nuclear Information System (INIS)

    Harms, S.E.; Fisher, C.F.; Fulmer, J.M.

    1989-01-01

    Magnetic resonance imaging provides superior contrast, resolution, and multiplanar imaging capability, allowing excellent definition of soft-tissue and bone marrow abnormalities. For these reasons, magnetic resonance imaging has become a major diagnostic imaging method for the evaluation of many musculoskeletal disorders. The applications of magnetic resonance imaging for musculoskeletal diagnosis are summarized and examples of common clinical situations are given. General guidelines are suggested for the musculoskeletal applications of magnetic resonance imaging

  17. Physics of Magnetic Resonance. Chapter 14

    Energy Technology Data Exchange (ETDEWEB)

    Song, Hee Kwon [Hospital of the University of Pennsylvania, Philadelphia (United States)

    2014-09-15

    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

  18. Magnetic resonance diagnosis of aortic dissection

    International Nuclear Information System (INIS)

    Mukohara, Nobuhiko; Yoshida, Yutaka; Nakamura, Kazuo

    1986-01-01

    Magnetic resonance imaging (MRI) was performed in thirty-one patients with aortic dissection to evaluate its usefulness in diagnosing the site of communicating orifice between the true and false lumens and the presence of retrograde dissection. 1. MRI revealed the site of the entry as a defect in the intimal flap in the images of 12 of 15 patients (80 %). 2. The site of the communicating orifice between the true and false lumens in the abdominal aorta could be determined in six of eight patients (75 %). 3. MRI diagnosis of retrograde dissection was successful in three patients. 4. Cross-sectional analysis of the abdominal aorta based on the location of the true lumen revealed that the celiac and superior mesenteric arteries tended to arise from the true lumen when the latter was situated in the anterior part of the abdominal aorta. The right and left renal arteries arose from the true lumen when it was positioned anterolaterally. In conclusion, MRI was a useful diagnostic method for aortic dissection, especially for determining the site of entry in the thoracic aorta. The changes in signal intensity in the false lumen provided useful information for locating the communicating orifice between the true and false lumens and for diagnosis of retrograde dissection. Cross-sectional analysis of dissection in the abdominal aorta was useful for predicting the branching of the main arteries from the true or false lumen. (author)

  19. Magnetic resonance of field-frozen and zero-field-frozen magnetic fluids

    International Nuclear Information System (INIS)

    Pereira, A.R.; Pelegrini, F.; Neto, K. Skeff; Buske, N.; Morais, P.C.

    2004-01-01

    In this study magnetic resonance was used to investigate magnetic fluid samples frozen under zero and non-zero (15 kG) external fields. The magnetite-based sample containing 2x10 17 particle/cm 3 was investigated from 100 to 400 K. Analysis of the temperature dependence of the resonance field revealed bigger magnetic structures in the frozen state than in the liquid phase. Also, differences in the mesoscopic organization in the frozen state may explain the data obtained from samples frozen under zero and non-zero fields

  20. 76 FR 58281 - Magnetic Resonance Imaging Safety; Public Workshop

    Science.gov (United States)

    2011-09-20

    ...] Magnetic Resonance Imaging Safety; Public Workshop AGENCY: Food and Drug Administration, HHS. ACTION... announcing a public workshop entitled: ``Magnetic Resonance Imaging (MRI) Safety Public Workshop.'' The purpose of the public workshop is to discuss factors affecting the safe use of magnetic resonance imaging...