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Sample records for resonance imaging dmri

  1. Diffusion microscopist simulator: a general Monte Carlo simulation system for diffusion magnetic resonance imaging.

    PubMed

    Yeh, Chun-Hung; Schmitt, Benoît; Le Bihan, Denis; Li-Schlittgen, Jing-Rebecca; Lin, Ching-Po; Poupon, Cyril

    2013-01-01

    This article describes the development and application of an integrated, generalized, and efficient Monte Carlo simulation system for diffusion magnetic resonance imaging (dMRI), named Diffusion Microscopist Simulator (DMS). DMS comprises a random walk Monte Carlo simulator and an MR image synthesizer. The former has the capacity to perform large-scale simulations of Brownian dynamics in the virtual environments of neural tissues at various levels of complexity, and the latter is flexible enough to synthesize dMRI datasets from a variety of simulated MRI pulse sequences. The aims of DMS are to give insights into the link between the fundamental diffusion process in biological tissues and the features observed in dMRI, as well as to provide appropriate ground-truth information for the development, optimization, and validation of dMRI acquisition schemes for different applications. The validity, efficiency, and potential applications of DMS are evaluated through four benchmark experiments, including the simulated dMRI of white matter fibers, the multiple scattering diffusion imaging, the biophysical modeling of polar cell membranes, and the high angular resolution diffusion imaging and fiber tractography of complex fiber configurations. We expect that this novel software tool would be substantially advantageous to clarify the interrelationship between dMRI and the microscopic characteristics of brain tissues, and to advance the biophysical modeling and the dMRI methodologies. PMID:24130783

  2. MO-C-17A-02: A Novel Method for Evaluating Hepatic Stiffness Based On 4D-MRI and Deformable Image Registration

    SciTech Connect

    Cui, T; Liang, X; Czito, B; Palta, M; Bashir, M; Yin, F; Cai, J

    2014-06-15

    Purpose: Quantitative imaging of hepatic stiffness has significant potential in radiation therapy, ranging from treatment planning to response assessment. This study aims to develop a novel, noninvasive method to quantify liver stiffness with 3D strains liver maps using 4D-MRI and deformable image registration (DIR). Methods: Five patients with liver cancer were imaged with an institutionally developed 4D-MRI technique under an IRB-approved protocol. Displacement vector fields (DVFs) across the liver were generated via DIR of different phases of 4D-MRI. Strain tensor at each voxel of interest (VOI) was computed from the relative displacements between the VOI and each of the six adjacent voxels. Three principal strains (E{sub 1}, E{sub 2} and E{sub 3}) of the VOI were derived as the eigenvalue of the strain tensor, which represent the magnitudes of the maximum and minimum stretches. Strain tensors for two regions of interest (ROIs) were calculated and compared for each patient, one within the tumor (ROI{sub 1}) and the other in normal liver distant from the heart (ROI{sub 2}). Results: 3D strain maps were successfully generated fort each respiratory phase of 4D-MRI for all patients. Liver deformations induced by both respiration and cardiac motion were observed. Differences in strain values adjacent to the distant from the heart indicate significant deformation caused by cardiac expansion during diastole. The large E{sub 1}/E{sub 2} (?2) and E{sub 1}/E{sub 2} (?10) ratios reflect the predominance of liver deformation in the superior-inferior direction. The mean E{sub 1} in ROI{sub 1} (0.12±0.10) was smaller than in ROI{sub 2} (0.15±0.12), reflecting a higher degree of stiffness of the cirrhotic tumor. Conclusion: We have successfully developed a novel method for quantitatively evaluating regional hepatic stiffness based on DIR of 4D-MRI. Our initial findings indicate that liver strain is heterogeneous, and liver tumors may have lower principal strain values than normal liver. Thorough validation of our method is warranted in future studies. NIH (1R21CA165384-01A1)

  3. A new method for joint susceptibility artefact correction and super-resolution for dMRI

    NASA Astrophysics Data System (ADS)

    Ruthotto, Lars; Mohammadi, Siawoosh; Weiskopf, Nikolaus

    2014-03-01

    Diffusion magnetic resonance imaging (dMRI) has become increasingly relevant in clinical research and neuroscience. It is commonly carried out using the ultra-fast MRI acquisition technique Echo-Planar Imaging (EPI). While offering crucial reduction of acquisition times, two limitations of EPI are distortions due to varying magnetic susceptibilities of the object being imaged and its limited spatial resolution. In the recent years progress has been made both for susceptibility artefact correction and increasing of spatial resolution using image processing and reconstruction methods. However, so far, the interplay between both problems has not been studied and super-resolution techniques could only be applied along one axis, the slice-select direction, limiting the potential gain in spatial resolution. In this work we describe a new method for joint susceptibility artefact correction and super-resolution in EPI-MRI that can be used to increase resolution in all three spatial dimensions and in particular increase in-plane resolutions. The key idea is to reconstruct a distortion-free, high-resolution image from a number of low-resolution EPI data that are deformed in different directions. Numerical results on dMRI data of a human brain indicate that this technique has the potential to provide for the first time in-vivo dMRI at mesoscopic spatial resolution (i.e. 500?m) a spatial resolution that could bridge the gap between white-matter information from ex-vivo histology (?1?m) and in-vivo dMRI (?2000?m).

  4. Four dimensional magnetic resonance imaging with retrospective k-space reordering: A feasibility study

    SciTech Connect

    Liu, Yilin; Yin, Fang-Fang; Cai, Jing; Chen, Nan-kuei; Chu, Mei-Lan

    2015-02-15

    Purpose: Current four dimensional magnetic resonance imaging (4D-MRI) techniques lack sufficient temporal/spatial resolution and consistent tumor contrast. To overcome these limitations, this study presents the development and initial evaluation of a new strategy for 4D-MRI which is based on retrospective k-space reordering. Methods: We simulated a k-space reordered 4D-MRI on a 4D digital extended cardiac-torso (XCAT) human phantom. A 2D echo planar imaging MRI sequence [frame rate (F) = 0.448 Hz; image resolution (R) = 256 × 256; number of k-space segments (N{sub KS}) = 4] with sequential image acquisition mode was assumed for the simulation. Image quality of the simulated “4D-MRI” acquired from the XCAT phantom was qualitatively evaluated, and tumor motion trajectories were compared to input signals. In particular, mean absolute amplitude differences (D) and cross correlation coefficients (CC) were calculated. Furthermore, to evaluate the data sufficient condition for the new 4D-MRI technique, a comprehensive simulation study was performed using 30 cancer patients’ respiratory profiles to study the relationships between data completeness (C{sub p}) and a number of impacting factors: the number of repeated scans (N{sub R}), number of slices (N{sub S}), number of respiratory phase bins (N{sub P}), N{sub KS}, F, R, and initial respiratory phase at image acquisition (P{sub 0}). As a proof-of-concept, we implemented the proposed k-space reordering 4D-MRI technique on a T2-weighted fast spin echo MR sequence and tested it on a healthy volunteer. Results: The simulated 4D-MRI acquired from the XCAT phantom matched closely to the original XCAT images. Tumor motion trajectories measured from the simulated 4D-MRI matched well with input signals (D = 0.83 and 0.83 mm, and CC = 0.998 and 0.992 in superior–inferior and anterior–posterior directions, respectively). The relationship between C{sub p} and N{sub R} was found best represented by an exponential function (C{sub P}=100(1?e{sup ?0.18N{sub R}}), when N{sub S} = 30, N{sub P} = 6). At a C{sub P} value of 95%, the relative error in tumor volume was 0.66%, indicating that N{sub R} at a C{sub P} value of 95% (N{sub R,95%}) is sufficient. It was found that N{sub R,95%} is approximately linearly proportional to N{sub P} (r = 0.99), and nearly independent of all other factors. The 4D-MRI images of the healthy volunteer clearly demonstrated respiratory motion in the diaphragm region with minimal motion induced noise or aliasing. Conclusions: It is feasible to generate respiratory correlated 4D-MRI by retrospectively reordering k-space based on respiratory phase. This new technology may lead to the next generation 4D-MRI with high spatiotemporal resolution and optimal tumor contrast, holding great promises to improve the motion management in radiotherapy of mobile cancers.

  5. MRI (Magnetic Resonance Imaging)

    MedlinePLUS

    ... Radiation-Emitting Products and Procedures Medical Imaging MRI (Magnetic Resonance Imaging) Share Tweet Linkedin Pin it More ... MB) Also available in Other Language versions . Description Magnetic resonance imaging (MRI) is a medical imaging procedure ...

  6. SU-E-J-157: Improving the Quality of T2-Weighted 4D Magnetic Resonance Imaging for Clinical Evaluation

    SciTech Connect

    Du, D; Mutic, S; Hu, Y; Caruthers, S; Glide-Hurst, C; Low, D

    2014-06-01

    Purpose: To develop an imaging technique that enables us to acquire T2- weighted 4D Magnetic Resonance Imaging (4DMRI) with sufficient spatial coverage, temporal resolution and spatial resolution for clinical evaluation. Methods: T2-weighed 4DMRI images were acquired from a healthy volunteer using a respiratory amplitude triggered T2-weighted Turbo Spin Echo sequence. 10 respiratory states were used to equally sample the respiratory range based on amplitude (0%, 20%i, 40%i, 60%i, 80%i, 100%, 80%e, 60%e, 40%e and 20%e). To avoid frequent scanning halts, a methodology was devised that split 10 respiratory states into two packages in an interleaved manner and packages were acquired separately. Sixty 3mm sagittal slices at 1.5mm in-plane spatial resolution were acquired to offer good spatial coverage and reasonable spatial resolution. The in-plane field of view was 375mm × 260mm with nominal scan time of 3 minutes 42 seconds. Acquired 2D images at the same respiratory state were combined to form the 3D image set corresponding to that respiratory state and reconstructed in the coronal view to evaluate whether all slices were at the same respiratory state. 3D image sets of 10 respiratory states represented a complete 4D MRI image set. Results: T2-weighted 4DMRI image were acquired in 10 minutes which was within clinical acceptable range. Qualitatively, the acquired MRI images had good image quality for delineation purposes. There were no abrupt position changes in reconstructed coronal images which confirmed that all sagittal slices were in the same respiratory state. Conclusion: We demonstrated it was feasible to acquire T2-weighted 4DMRI image set within a practical amount of time (10 minutes) that had good temporal resolution (10 respiratory states), spatial resolution (1.5mm × 1.5mm × 3.0mm) and spatial coverage (60 slices) for future clinical evaluation.

  7. Magnetic Resonance Imaging (MRI)

    MedlinePLUS

    ... Your Best Self Smart Snacking Losing Weight Safely Magnetic Resonance Imaging (MRI) KidsHealth > Teens > Cancer Center > Diagnostic Tests > Magnetic Resonance Imaging (MRI) Print A A A Text Size What's ...

  8. SU-D-18C-01: A Novel 4D-MRI Technology Based On K-Space Retrospective Sorting

    SciTech Connect

    Liu, Y; Yin, F; Cai, J

    2014-06-01

    Purpose: Current 4D-MRI techniques lack sufficient temporal/spatial resolution and consistent tumor contrast. To overcome these limitations, this study presents the development and initial evaluation of an entirely new framework of 4D-MRI based on k-space retrospective sorting. Methods: An important challenge of the proposed technique is to determine the number of repeated scans(NR) required to obtain sufficient k-space data for 4D-MRI. To do that, simulations using 29 cancer patients' respiratory profiles were performed to derive the relationship between data acquisition completeness(Cp) and NR, also relationship between NR(Cp=95%) and the following factors: total slice(NS), respiratory phase bin length(Lb), frame rate(fr), resolution(R) and image acquisition starting-phase(P0). To evaluate our technique, a computer simulation study on a 4D digital human phantom (XCAT) were conducted with regular breathing (fr=0.5Hz; R=256×256). A 2D echo planer imaging(EPI) MRI sequence were assumed to acquire raw k-space data, with respiratory signal and acquisition time for each k-space data line recorded simultaneously. K-space data was re-sorted based on respiratory phases. To evaluate 4D-MRI image quality, tumor trajectories were measured and compared with the input signal. Mean relative amplitude difference(D) and cross-correlation coefficient(CC) are calculated. Finally, phase-sharing sliding window technique was applied to investigate the feasibility of generating ultra-fast 4D-MRI. Result: Cp increased with NR(Cp=100*[1-exp(-0.19*NR)], when NS=30, Lb=100%/6). NR(Cp=95%) was inversely-proportional to Lb (r=0.97), but independent of other factors. 4D-MRI on XCAT demonstrated highly accurate motion information (D=0.67%, CC=0.996) with much less artifacts than those on image-based sorting 4D-MRI. Ultra-fast 4D-MRI with an apparent temporal resolution of 10 frames/second was reconstructed using the phase-sharing sliding window technique. Conclusions: A novel 4D-MRI technology based on k-space sorting has been successfully developed and evaluated on the digital phantom. Framework established can be applied to a variety of MR sequences, showing great promises to develop the optimal 4D-MRI technique for many radiation therapy applications. NIH (1R21CA165384-01A1)

  9. Parallel Magnetic Resonance Imaging

    E-print Network

    Uecker, Martin

    2015-01-01

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

  10. [Cardiovascular magnetic resonance imaging].

    PubMed

    Teraoka, Kunihiko; Suzuki, Yoshinori; Yamashina, Akira

    2014-07-01

    Cardiac magnetic resonance imaging (CMR) evolves and is occupying an important status in cardiovascular diagnostic imaging. In particular, in the estimation of the cause of heart failure, or evaluation of severity-of-illness and prognostic presumption, utility is high clinically. In this chapter, about a selection sequence for taking image according to the purpose, description of findings, and its clinical utility are introduced. And the role which this imaging plays will be discussed in the near future. PMID:25138928

  11. Nanoscale magnetic resonance imaging

    PubMed Central

    Degen, C. L.; Poggio, M.; Mamin, H. J.; Rettner, C. T.; Rugar, D.

    2009-01-01

    We have combined ultrasensitive magnetic resonance force microscopy (MRFM) with 3D image reconstruction to achieve magnetic resonance imaging (MRI) with resolution <10 nm. The image reconstruction converts measured magnetic force data into a 3D map of nuclear spin density, taking advantage of the unique characteristics of the “resonant slice” that is projected outward from a nanoscale magnetic tip. The basic principles are demonstrated by imaging the 1H spin density within individual tobacco mosaic virus particles sitting on a nanometer-thick layer of adsorbed hydrocarbons. This result, which represents a 100 million-fold improvement in volume resolution over conventional MRI, demonstrates the potential of MRFM as a tool for 3D, elementally selective imaging on the nanometer scale. PMID:19139397

  12. Magnetic resonance imaging

    SciTech Connect

    Stark, D.D.; Bradley, W.G. Jr.

    1988-01-01

    The authors present a review of magnetic resonance imaging. Many topics are explored from instrumentation, spectroscopy, blood flow and sodium imaging to detailed clinical applications such as the differential diagnosis of multiple sclerosis or adrenal adenoma. The emphasis throughout is on descriptions of normal multiplanar anatomy and pathology as displayed by MRI.

  13. Functional Magnetic Resonance Imaging

    ERIC Educational Resources Information Center

    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…

  14. Magnetic Resonance Imaging

    PubMed Central

    Fache, J. Stephen

    1986-01-01

    Magnetic resonance imaging (MRI) is an important new imaging modality just arriving on the clinical scene in Canada. MRI uses no ionizing radiation; images are derived from the interaction of hydrogen nuclei, a powerful magnetic field, and radio waves. Images are displayed as tomographic slices, much like CT. Direct transverse, sagittal, coronal or oblique slices can be obtained. Unlike CT, the MRI image does not reflect varying tissue densities. In MRI, tissues are differentiated by variation in the amount of hydrogen they contain and by differences in the magnetic environment at a molecular level. All parts of the body can be examined with MRI, although the CNS is particularly well visualized. In addition to providing high resolution images, MRI has the potential for performing non-invasive angiography and biochemical analysis through spectroscopy. To date, there are no known harmful effects of MRI. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5 PMID:21267205

  15. Magnetic Resonance Imaging (MRI): Brain

    MedlinePLUS

    ... Kids Deal With Bullies Pregnant? What to Expect Magnetic Resonance Imaging (MRI): Brain KidsHealth > Parents > Doctors & Hospitals > Medical Tests & Exams > Magnetic Resonance Imaging (MRI): Brain Print A A A ...

  16. Introduction Magnetic Resonance Imaging (MRI)

    E-print Network

    Wirosoetisno, Djoko

    Introduction Statistics Magnetic Resonance Imaging (MRI) Statistics in the UK Statistics at UCL and Beyond #12;Introduction Statistics Magnetic Resonance Imaging (MRI) Statistics in the UK Statistics Magnetic Resonance Imaging (MRI) Statistics in the UK Statistics at UCL Outline Why do Statistics? Some

  17. Multidimensionally Encoded Magnetic Resonance Imaging

    E-print Network

    Multidimensionally Encoded Magnetic Resonance Imaging Fa-Hsuan Lin1,2 * Magnetic resonance imaging-dimensional spatial bases created by linear spa- tial encoding magnetic fields (SEMs). Recently, imaging strat- egies gradients INTRODUCTION The spatial localization of magnetic resonance (MR) sig- nals has been commonly

  18. SU-E-J-192: Verification of 4D-MRI Internal Target Volume Using Cine MRI

    SciTech Connect

    Lafata, K; Czito, B; Palta, M; Bashir, M; Yin, F; Cai, J

    2014-06-01

    Purpose: To investigate the accuracy of 4D-MRI in determining the Internal Target Volume (ITV) used in radiation oncology treatment planning of liver cancers. Cine MRI is used as the standard baseline in establishing the feasibility and accuracy of 4D-MRI tumor motion within the liver. Methods: IRB approval was obtained for this retrospective study. Analysis was performed on MR images from four patients receiving external beam radiation therapy for liver cancer at our institution. Eligible patients received both Cine and 4D-MRI scans before treatment. Cine images were acquired sagittally in real time at a slice bisecting the tumor, while 4D images were acquired volumetrically. Cine MR DICOM headers were manipulated such that each respiratory frame was assigned a unique slice location. This approach permitted the treatment planning system (Eclipse, Varian Medical Systems) to recognize a complete respiratory cycle as a “volume”, where the gross tumor was contoured temporally. Software was developed to calculate the union of all frame contours in the structure set, resulting in the corresponding plane of the ITV projecting through the middle of the tumor, defined as the Internal Target Area (ITA). This was repeated for 4D-MRI, at the corresponding slice location, allowing a direct comparison of ITAs obtained from each modality. Results: Four patients have been analyzed. ITAs contoured from 4D-MRI correlate with contours from Cine MRI. The mean error of 4D values relative to Cine values is 7.67 +/? 2.55 %. No single ITA contoured from 4D-MRI demonstrated more than 10.5 % error compared to its Cine MRI counterpart. Conclusion: Motion management is a significant aspect of treatment planning within dynamic environments such as the liver, where diaphragmatic and cardiac activity influence plan accuracy. This small pilot study suggests that 4D-MRI based ITA measurements agree with Cine MRI based measurements, an important step towards clinical implementation. NIH 1R21CA165384-01A1.

  19. Cardiovascular Magnetic Resonance Imaging

    NASA Astrophysics Data System (ADS)

    Pelc, Norbert

    2000-03-01

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

  20. An Optimal Dimensionality Sampling Scheme on the Sphere for Antipodal Signals In Diffusion Magnetic Resonance Imaging

    E-print Network

    Bates, Alice P; Kennedy, Rodney A

    2015-01-01

    We propose a sampling scheme on the sphere and develop a corresponding spherical harmonic transform (SHT) for the accurate reconstruction of the diffusion signal in diffusion magnetic resonance imaging (dMRI). By exploiting the antipodal symmetry, we design a sampling scheme that requires the optimal number of samples on the sphere, equal to the degrees of freedom required to represent the antipodally symmetric band-limited diffusion signal in the spectral (spherical harmonic) domain. Compared with existing sampling schemes on the sphere that allow for the accurate reconstruction of the diffusion signal, the proposed sampling scheme reduces the number of samples required by a factor of two or more. We analyse the numerical accuracy of the proposed SHT and show through experiments that the proposed sampling allows for the accurate and rotationally invariant computation of the SHT to near machine precision accuracy.

  1. Molecular magnetic resonance imaging

    PubMed Central

    Hengerer, A; Grimm, J

    2006-01-01

    Molecular MRI (mMRI) is a special implementation of Molecular Imaging for the non-invasive visualisation of biological processes at the cellular and molecular level. More specifically, mMRI comprises the contrast agent-mediated alteration of tissue relaxation times for the detection and localisation of molecular disease markers (such as cell surface receptors, enzymes or signaling molecules), cells (e.g. lymphocytes, stem cells) or therapeutic drugs (e.g. liposomes, viral particles). MRI yields topographical, anatomical maps; functional MRI (fMRI) provides rendering of physiologic functions and magnetic resonance spectroscopy (MRS) reveals the distribution patterns of some specific metabolites. mMRI provides an additional level of information at the molecular or cellular level, thus extending MRI further beyond the anatomical and physiological level. These advances brought by mMRI are mandatory for MRI to be competitive in the age of molecular medicine. mMRI is already today increasingly used for research purposes, e.g. to facilitate the examination of cell migration, angiogenesis, apoptosis or gene expression in living organisms. In medical diagnostics, mMRI will pave the way toward a significant improvement in early detection of disease, therapy planning or monitoring of outcome and will therefore bring significant improvement in the medical treatment for patients. In general, Molecular Imaging demands high sensitivity equipment, capable of quantitative measurements to detect probes that interact with targets at the pico- or nanomolar level. The challenge to detect such sparse targets can be exemplified with cell surface receptors, a common target for molecular imaging. At high expression levels (bigger than 106 per cell) the receptor concentration is approx. 1015 per ml, i.e. the concentration is in the micromole range. Many targets, however, are expressed in even considerably lower concentrations. Therefore the most sensitive modalities, namely nuclear imaging (PET and SPECT) have always been at the forefront of Molecular Imaging, and many nuclear probes in clinical use today are already designed to detect molecular mechanisms (such as FDG, detecting high glucose metabolism). In recent years however, Molecular Imaging has commanded attention from beyond the field of nuclear medicine. Further imaging modalities to be considered for molecular imaging primarily include optical imaging, MRI and ultrasound. PMID:21614236

  2. Bayesian Optimization of Magnetic Resonance Imaging Sequences

    E-print Network

    Seeger, Matthias

    Bayesian Optimization of Magnetic Resonance Imaging Sequences Matthias Seeger MMCI Cluster) Bayesian MRI Optimization 28 November 2008 2 / 19 #12;Magnetic Resonance Imaging Magnetic Resonance Imaging) Bayesian MRI Optimization 28 November 2008 3 / 19 #12;Magnetic Resonance Imaging Magnetic Resonance Imaging

  3. A connectivity-based test-retest dataset of multi-modal magnetic resonance imaging in young healthy adults

    PubMed Central

    Lin, Qixiang; Dai, Zhengjia; Xia, Mingrui; Han, Zaizhu; Huang, Ruiwang; Gong, Gaolang; Liu, Chao; Bi, Yanchao; He, Yong

    2015-01-01

    Recently, magnetic resonance imaging (MRI) has been widely used to investigate the structures and functions of the human brain in health and disease in vivo. However, there are growing concerns about the test-retest reliability of structural and functional measurements derived from MRI data. Here, we present a test-retest dataset of multi-modal MRI including structural MRI (S-MRI), diffusion MRI (D-MRI) and resting-state functional MRI (R-fMRI). Fifty-seven healthy young adults (age range: 19–30 years) were recruited and completed two multi-modal MRI scan sessions at an interval of approximately 6 weeks. Each scan session included R-fMRI, S-MRI and D-MRI data. Additionally, there were two separated R-fMRI scans at the beginning and at the end of the first session (approximately 20?min apart). This multi-modal MRI dataset not only provides excellent opportunities to investigate the short- and long-term test-retest reliability of the brain’s structural and functional measurements at the regional, connectional and network levels, but also allows probing the test-retest reliability of structural-functional couplings in the human brain. PMID:26528395

  4. Optically Detected Magnetic Resonance Imaging

    E-print Network

    Blank, Aharon; Fischer, Ran; London, Paz; Gershoni, David

    2014-01-01

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

  5. Optically detected magnetic resonance imaging

    SciTech Connect

    Blank, Aharon; Shapiro, Guy; Fischer, Ran; London, Paz; Gershoni, David

    2015-01-19

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

  6. Low field magnetic resonance imaging

    DOEpatents

    Pines, Alexander (Berkeley, CA); Sakellariou, Dimitrios (Billancourt, FR); Meriles, Carlos A. (Fort Lee, NJ); Trabesinger, Andreas H. (London, GB)

    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.

  7. Magnetic Resonance Imaging of concrete

    E-print Network

    Burgoyne, Chris

    1 Magnetic Resonance Imaging of concrete Dr Chris Burgoyne Department of Engineering University of Cambridge Assessment of Concrete Structures · How can we tell what is going on inside concrete? · We would like to know:- · Has the concrete hardened? · Is there corrosion? · Is there cracking? · Where

  8. Magnetic Resonance Imaging (MRI)

    Cancer.gov

    Different tissues (including tumors) emit a more or less intense signal based on their chemical makeup, so a picture of the body organs can be displayed on a computer screen. Much like CT scans, MRI can produce three-dimensional images of sections of the body, but MRI is sometimes more sensitive than CT scans for distinguishing soft tissues.

  9. Magnetic Resonance Imaging (MRI) during Pregnancy

    MedlinePLUS

    ... during the exam? Contrast material MRI during pregnancy Magnetic resonance imaging (MRI) If you are pregnant and your doctor wants to perform a magnetic resonance imaging (MRI) exam, there is a possibility ...

  10. Magnetic Resonance Imaging (MRI): Lumbar Spine

    MedlinePLUS

    ... Kids Deal With Bullies Pregnant? What to Expect Magnetic Resonance Imaging (MRI): Lumbar Spine KidsHealth > Parents > Doctors & Hospitals > Medical Tests & Exams > Magnetic Resonance Imaging (MRI): Lumbar Spine Print A A ...

  11. Interventional Cardiovascular Magnetic Resonance Imaging

    PubMed Central

    Saikus, Christina E.; Lederman, Robert J.

    2010-01-01

    Cardiovascular magnetic resonance (CMR) combines excellent soft-tissue contrast, multiplanar views, and dynamic imaging of cardiac function without ionizing radiation exposure. Interventional cardiovascular magnetic resonance (iCMR) leverages these features to enhance conventional interventional procedures or to enable novel ones. Although still awaiting clinical deployment, this young field has tremendous potential. We survey promising clinical applications for iCMR. Next, we discuss the technologies that allow CMR-guided interventions and, finally, what still needs to be done to bring them to the clinic. PMID:19909937

  12. Nuclear Magnetic Resonance Imaging Jeffrey A. Fessler

    E-print Network

    Fessler, Jeffrey A.

    Nuclear Magnetic Resonance Imaging Jeffrey A. Fessler EECS Department The University of Michigan RW, Jesmanowicz A, Hyde JS, Real-time functional magnetic resonance imaging. Magnetic Resonance NSS-MIC: Fundamentals of Medical Imaging Oct. 20, 2003 NMR-0 c J. Fessler, September 13, 2003

  13. Classification on Brain Functional Magnetic Resonance Imaging

    E-print Network

    Classification on Brain Functional Magnetic Resonance Imaging: Dimensionality, Sample Size, Subject magnetic resonance imaging. We propose a synthetic model for the systematic study of as- pects generalization ac- curacy. 1 Introduction Functional magnetic resonance imaging (fMRI) has become one of the meth

  14. Magnetic Resonance Imaging of Electrolysis.

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  15. Magnetic Resonance Imaging of Electrolysis.

    PubMed Central

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

    2015-01-01

    This study explores the hypothesis that Magnetic Resonance Imaging (MRI) can image the process of electrolysis by detecting pH fronts. The study has relevance to real time control of cell ablation with electrolysis. To investigate the hypothesis we compare the following MR imaging sequences: T1 weighted, T2 weighted and Proton Density (PD), with optical images acquired using pH-sensitive dyes embedded in a physiological saline agar solution phantom treated with electrolysis and discrete measurements with a pH microprobe. We further demonstrate the biological relevance of our work using a bacterial E. Coli model, grown on the phantom. The results demonstrate the ability of MRI to image electrolysis produced pH changes in a physiological saline phantom and show that these changes correlate with cell death in the E. Coli model grown on the phantom. The results are promising and invite further experimental research. PMID:25659942

  16. Magnetic resonance imaging in pancreatitis.

    PubMed

    Balci, Numan Cem; Bieneman, B Kirke; Bilgin, Mehmet; Akduman, Isin E; Fattahi, Rana; Burton, Frank R

    2009-02-01

    Pancreatitis can occur in acute and chronic forms. Magnetic resonance imaging (MRI) plays an important role in the early diagnosis of both conditions and complications that may arise from acute or chronic inflammation of the gland. Standard MRI techniques including T1-weighted and T2-weighted fat-suppressed imaging sequences together with contrast-enhanced imaging can both aid in the diagnosis of acute pancreatitis and demonstrate complications as pseudocysts, hemorrhage, and necrosis. Combined use of MRI and MR cholangiopancreatography can show both parenchymal findings that are associated with chronic pancreatitis including pancreatic size and signal and arterial enhancements, all of which are diminished in chronic pancreatitis. The degree of main pancreatic duct dilatation and/or the number of side branch ectasia determines the diagnosis of chronic pancreatitis and its severity. In this paper, we report the spectrum of imaging findings of acute and chronic pancreatitis on MRI and MR cholangiopancreatography. PMID:19687723

  17. Building a Birdcage Resonator for Magnetic Resonance Imaging Studies of CNS Disorders

    E-print Network

    Martin, Jeff

    Building a Birdcage Resonator for Magnetic Resonance Imaging Studies of CNS Disorders Michael Lang Winnipeg, MB Canada April 20, 2011 #12;Abstract Magnetic resonance imaging (MRI) studies are currently use Magnetic Resonance Imaging . . . . . . . . . . . . . . . . . . . . . 1 2 Nuclear Magnetic

  18. Magnetic resonance imaging: Principles and applications

    SciTech Connect

    Kean, D.; Smith, M.

    1986-01-01

    This text covers the physics underlying magnetic resonance (MR) imaging; pulse sequences; image production; equipment; aspects of clinical imaging; and the imaging of the head and neck, thorax, abdomen and pelvis, and musculoskeletal system; and MR imaging. The book provides about 150 examples of MR images that give an overview of the pathologic conditions imaged. There is a discussion of the physics of MR imaging and also on the spin echo.

  19. Blount's disease: magnetic resonance imaging.

    PubMed

    Ducou le Pointe, H; Mousselard, H; Rudelli, A; Montagne, J P; Filipe, G

    1995-01-01

    To evaluate the information obtained by magnetic resonance (MR) imaging, the radiographic and MR investigations of nine patients treated for idiopathic tibia vara were reviewed in retrospect. There were six unilateral and three bilateral cases (12 tibiae). Initial radiographs of each patient were assigned a stage according to Catonné's classification. MR imaging was performed with a 0.5- or 1.5-T apparatus. Bony epiphyses were poorly developed in all cases. The cartilaginous component of the epiphyses compensated partially (6/12 cases) or completely (6/12 cases) for the collapse of the physes. In two cases an abnormal area was found between the medial meniscus and the cartilaginous portion of the epiphysis. An abnormally large medial meniscus was noted in four cases; an abnormal signal in the medial meniscus was seen in two cases. MR imaging has several advantages over plain film: it uses no ionizing radiation, it shows the shape of the ossified and cartilaginous epiphysis, and it demonstrates meniscal and physeal abnormalities. MR imaging may influence the choice of treatment. PMID:7761151

  20. Artifacts in magnetic resonance imaging.

    PubMed

    Krupa, Katarzyna; Bekiesi?ska-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. PMID:25745524

  1. Artifacts in Magnetic Resonance Imaging

    PubMed Central

    Krupa, Katarzyna; Bekiesi?ska-Figatowska, Monika

    2015-01-01

    Summary 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. PMID:25745524

  2. Chapter 3 Set Redundancy in Magnetic Resonance Brain Images 3.1 MRI (magnetic resonance imaging)

    E-print Network

    Qi, Xiaojun

    16 Chapter 3 Set Redundancy in Magnetic Resonance Brain Images 3.1 MRI (magnetic resonance imaging focuses on brain structures but will include other image types to demonstrate our techniques. MRI systems produce brain images in cross-sections of a human head. These brain images are acquired by measuring

  3. TRZASKO AND MANDUCA: HIGHLY UNDERSAMPLED MAGNETIC RESONANCE IMAGE RECONSTRUCTION VIA HOMOTOPIC L0-MINIMIZATION 1 Highly Undersampled Magnetic Resonance Image

    E-print Network

    Zhang, Li

    TRZASKO AND MANDUCA: HIGHLY UNDERSAMPLED MAGNETIC RESONANCE IMAGE RECONSTRUCTION VIA HOMOTOPIC L0-MINIMIZATION 1 Highly Undersampled Magnetic Resonance Image Reconstruction via Homotopic L0-Minimization Joshua: Magnetic Resonance Imaging (MRI), Image Reconstruction, Compressive Sensing, Compressed Sensing, Nonconvex

  4. Pocket atlas of cranial magnetic resonance imaging

    SciTech Connect

    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. An Overview of Magnetic Resonance Imaging (MRI)

    E-print Network

    Heller, Barbara

    An Overview of Magnetic Resonance Imaging (MRI) Academic Resource Center #12;Table of Contents imaging technique that records changing magnetic fields · Also called Nuclear Magnetic Resonance (NMR · What is MRI? · General · MRI Machine · Who is it for? · How does it work? · Magnetization vector

  6. Functional Magnetic Resonance Imaging and Pediatric Anxiety

    ERIC Educational Resources Information Center

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

    2008-01-01

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

  7. Linear constraint minimum variance beamformer functional magnetic resonance inverse imaging

    E-print Network

    Linear constraint minimum variance beamformer functional magnetic resonance inverse imaging Fa) beamformer localization method to reconstruct single-shot volumetric functional magnetic resonance imaging (f The overall temporal resolution of magnetic resonance imaging (MRI) is limited by the time required

  8. Safety Guidelines for Conducting Magnetic Resonance Imaging (MRI) Experiments Involving

    E-print Network

    California at San Diego, University of

    Safety Guidelines for Conducting Magnetic Resonance Imaging (MRI) Experiments Involving Human Subjects Center for Functional Magnetic Resonance Imaging University of California, San Diego July 2007 files at the Center's administrative office. Facilities UCSD's Functional Magnetic Resonance Imaging

  9. Unsupervised orthogonal subspace projection approach to magnetic resonance image

    E-print Network

    Chang, Chein-I

    Unsupervised orthogonal subspace projection approach to magnetic resonance image classification have witnessed that some techniques that were devel- oped for magnetic resonance imaging (MRI) found technique, called or- thogonal subspace projection (OSP), to magnetic resonance image clas- sification

  10. Magnetic Resonance Imaging of Electroconvection in a Polar Organic Solvent

    E-print Network

    Augustine, Mathew P.

    Magnetic Resonance Imaging of Electroconvection in a Polar Organic Solvent Scott A. Riley solvent nitrobenzene induced by an electric field is studied by magnetic resonance imaging. Rf pulse; magnetic resonance imaging; molecular motion. INTRODUCTION Determination of chemical structure

  11. Evaluation of COPD's diaphragm motion extracted from 4D-MRI

    NASA Astrophysics Data System (ADS)

    Swastika, Windra; Masuda, Yoshitada; Kawata, Naoko; Matsumoto, Koji; Suzuki, Toshio; Iesato, Ken; Tada, Yuji; Sugiura, Toshihiko; Tanabe, Nobuhiro; Tatsumi, Koichiro; Ohnishi, Takashi; Haneishi, Hideaki

    2015-03-01

    We have developed a method called intersection profile method to construct a 4D-MRI (3D+time) from time-series of 2D-MRI. The basic idea is to find the best matching of the intersection profile from the time series of 2D-MRI in sagittal plane (navigator slice) and time series of 2D-MRI in coronal plane (data slice). In this study, we use 4D-MRI to semiautomatically extract the right diaphragm motion of 16 subjects (8 healthy subjects and 8 COPD patients). The diaphragm motion is then evaluated quantitatively by calculating the displacement of each subjects and normalized it. We also generate phase-length map to view and locate paradoxical motion of the COPD patients. The quantitative results of the normalized displacement shows that COPD patients tend to have smaller displacement compared to healthy subjects. The average normalized displacement of total 8 COPD patients is 9.4mm and the average of normalized displacement of 8 healthy volunteers is 15.3mm. The generated phase-length maps show that not all of the COPD patients have paradoxical motion, however if it has paradoxical motion, the phase-length map is able to locate where does it occur.

  12. Imaging agents for in vivo magnetic resonance and scintigraphic imaging

    DOEpatents

    Engelstad, Barry L. (Orinda, CA); Raymond, Kenneth N. (Berkeley, CA); Huberty, John P. (Corte Madera, CA); White, David L. (Oakland, CA)

    1991-01-01

    Methods are provided for in vivo magnetic resonance imaging and/or scintigraphic imaging of a subject using chelated transition metal and lanthanide metal complexes. Novel ligands for these complexes are provided.

  13. Imaging agents for in vivo magnetic resonance and scintigraphic imaging

    DOEpatents

    Engelstad, B.L.; Raymond, K.N.; Huberty, J.P.; White, D.L.

    1991-04-23

    Methods are provided for in vivo magnetic resonance imaging and/or scintigraphic imaging of a subject using chelated transition metal and lanthanide metal complexes. Novel ligands for these complexes are provided. No Drawings

  14. Magnetic resonance imaging of diabetic foot complications

    PubMed Central

    Low, Keynes TA; Peh, Wilfred CG

    2015-01-01

    This pictorial review aims to illustrate the various manifestations of the diabetic foot on magnetic resonance (MR) imaging. The utility of MR imaging and its imaging features in the diagnosis of pedal osteomyelitis are illustrated. There is often difficulty encountered in distinguishing osteomyelitis from neuroarthropathy, both clinically and on imaging. By providing an accurate diagnosis based on imaging, the radiologist plays a significant role in the management of patients with complications of diabetic foot. PMID:25640096

  15. Stepped Impedance Resonators for High Field Magnetic Resonance Imaging

    PubMed Central

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

    2014-01-01

    Multi-element volume radio-frequency (RF) coils are an integral aspect of the growing field of high field magnetic resonance imaging (MRI). In these systems, a popular volume coil of choice has become the transverse electromagnetic (TEM) multi-element transceiver coil consisting of microstrip resonators. In this paper, to further advance this design approach, a new microstrip resonator strategy in which the transmission line is segmented into alternating impedance sections referred to as stepped impedance resonators (SIRs) is investigated. Single element simulation results in free space and in a phantom at 7 tesla (298 MHz) demonstrate the rationale and feasibility of the SIR design strategy. Simulation and image results at 7 tesla in a phantom and human head illustrate the improvements in transmit magnetic field, as well as, RF efficiency (transmit magnetic field versus SAR) when two different SIR designs are incorporated in 8-element volume coil configurations and compared to a volume coil consisting of microstrip elements. PMID:23508243

  16. Single echo acquisition magnetic resonance imaging 

    E-print Network

    McDougall, Mary Preston

    2006-04-12

    The dramatic improvement in magnetic resonance imaging (MRI) scan time over the past fifteen years through gradient-based methods that sample k-space more efficiently and quickly cannot be sustained, as thresholds regarding hardware and safety...

  17. Magnetic resonance imaging in cardiovascular disease 

    E-print Network

    Richards, Jennifer Margaret Jane

    2013-07-06

    Background Superparamagnetic particles of iron oxide (SPIO) are part of a novel and exciting class of ‘smart’ magnetic resonance imaging (MRI) contrast agents that are taken up by inflammatory cells. Ultrasmall SPIO ...

  18. Surface Plasmon Resonance Imaging Measurements of Electrostatic Biopolymer

    E-print Network

    Surface Plasmon Resonance Imaging Measurements of Electrostatic Biopolymer Adsorption onto surface plasmon resonance (SPR) imaging experiments is used to charac- terize the differential/RAS) and surface plasmon resonance (SPR) thickness mea- surements. A schematic diagram of the scanning SPR

  19. Adaptive alternating minimization for fitting magnetic resonance spectroscopic imaging

    E-print Network

    Adaptive alternating minimization for fitting magnetic resonance spectroscopic imaging signals the problem of modeling Magnetic Resonance Spectroscopic Imaging (MRSI) signals, in the aim of estimating than independently fitting each signal in the grid. 1 Introduction Magnetic Resonance (MR) is widely

  20. Array combination for parallel imaging in Magnetic Resonance Imaging 

    E-print Network

    Spence, Dan Kenrick

    2007-09-17

    In Magnetic Resonance Imaging, the time required to generate an image is proportional to the number of steps used to encode the spatial information. In rapid imaging, an array of coil elements and receivers are used to reduce the number of encoding...

  1. Simple and Inexpensive Classroom Demonstrations of Nuclear Magnetic Resonance and Magnetic Resonance Imaging.

    ERIC Educational Resources Information Center

    Olson, Joel A.; Nordell, Karen J.; Chesnik, Marla A.; Landis, Clark R.; Ellis, Arthur B.; Rzchowski, M. S.; Condren, S. Michael; Lisensky, George C.

    2000-01-01

    Describes a set of simple, inexpensive, classical demonstrations of nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) principles that illustrate the resonance condition associated with magnetic dipoles and the dependence of the resonance frequency on environment. (WRM)

  2. Brain Morphometry Using Anatomical Magnetic Resonance Imaging

    ERIC Educational Resources Information Center

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

    2008-01-01

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

  3. [Functional magnetic resonance imaging of the kidneys].

    PubMed

    Lanzman, R S; Notohamiprodjo, M; Wittsack, H J

    2015-12-01

    Interest in functional renal magnetic resonance imaging (MRI) has significantly increased in recent years. This review article provides an overview of the most important functional imaging techniques and their potential clinical applications for assessment of native and transplanted kidneys, with special emphasis on the clarification of renal tumors. PMID:26628260

  4. Apparatus for investigating resonance with application to magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Murphy, Sytil; Jones, Dyan L.; Gross, Josh; Zollman, Dean

    2015-11-01

    Resonance is typically studied in the context of either a pendulum or a mass on a spring. We have developed an apparatus that enables beginning students to investigate resonant behavior of changing magnetic fields, in addition to the properties of the magnetic field due to a wire and the superposition of magnetic fields. In this resonant system, a compass oscillates at a frequency determined by the compass's physical properties and an external magnetic field. While the analysis is mathematically similar to that of the pendulum, this apparatus has an advantage that the magnetic field is easily controlled, while it is difficult to control the strength of gravity. This apparatus has been incorporated into a teaching module on magnetic resonance imaging.

  5. Magnetic Resonance Imaging (MRI) -- Head

    MedlinePLUS Videos and Cool Tools

    ... imaging methods. This exam does not use ionizing radiation and may require an injection of a contrast ... internal body structures. MRI does not use ionizing radiation (x-rays). Detailed MR images allow physicians to ...

  6. Magnetic resonance imaging of the body

    SciTech Connect

    Higgins, C.B.; Hricak, H.

    1987-01-01

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

  7. A NEW CLUSTERING ALGORITHM FOR SEGMENTATION OF MAGNETIC RESONANCE IMAGES

    E-print Network

    Slatton, Clint

    A NEW CLUSTERING ALGORITHM FOR SEGMENTATION OF MAGNETIC RESONANCE IMAGES By ERHAN GOKCAY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Magnetic Resonance Image Segmentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Image Formation in MRI

  8. Diffusion magnetic resonance imaging of chest tumors

    PubMed Central

    2012-01-01

    Abstract This review provides an overview of the current status of the published data on diffusion magnetic resonance (MR) imaging of chest tumors. Diffusion MR imaging is a non-invasive imaging technique that measures the differences in water mobility in different tissue microstructures and quantifies them based on the apparent diffusion coefficient. Diffusion MR imaging has been used for the characterization, grading and staging of lung cancer as well as for differentiating central tumors from post-obstructive consolidation. In addition, this technique helps in differentiating malignant from benign pulmonary and mediastinal tumors as well as in the characterization of pleural mesothelioma and effusion. Diffusion MR imaging can be incorporated into routine morphological MR imaging to improve radiologist confidence in image interpretation and to provide functional assessments of chest tumors during the same examination. Diffusion MR imaging could be used in the future as a functional imaging technique for tumors of the chest. PMID:23108223

  9. Original Research In Vivo Magnetic Resonance Imaging of the Human

    E-print Network

    Gorassini, Monica

    Original Research In Vivo Magnetic Resonance Imaging of the Human Cervical Spinal Cord at 3 Tesla. Magn. Reson. Imaging 2002;16:21­27. © 2002 Wiley-Liss, Inc. HIGH-RESOLUTION MAGNETIC RESONANCE imaging Beaulieu, PhD1* Purpose: To demonstrate the feasibility of obtaining high- quality magnetic resonance (MR

  10. Ferromagnetic resonance imaging of Co films using magnetic resonance force microscopy

    E-print Network

    Hammel, P. Chris

    Ferromagnetic resonance imaging of Co films using magnetic resonance force microscopy B. J. Suh, P resonance FMR 2 has been demonstrated. Each of these has advantages for micro- scopic imaging in magnetic the spatial origin of a particular contribu- tion to the FMR signal. Magnetic resonance imaging employs

  11. Magnetic resonance imaging in traumatic hip subluxation

    PubMed Central

    Flanigan, David C; De Smet, Arthur A; Graf, Ben

    2011-01-01

    Athletic traumatic hip subluxations are rare. Classic radiographic features have been well described. This case highlights the potential pitfalls of immediate magnetic resonance imaging. Femoral head contusions and acetabular rim fractures are common associated findings usually apparent with magnetic resonance imaging (MRI). However, in this case an MRI done 3 hours post injury failed to show any edema in either location, making the appearance of these findings on subsequent MRIs difficult to interpret. An acute MRI more than 48 hours post injury may have been more helpful. PMID:21559109

  12. Review: Magnetic resonance imaging techniques in ophthalmology

    PubMed Central

    Fagan, Andrew J.

    2012-01-01

    Imaging the eye with magnetic resonance imaging (MRI) has proved difficult due to the eye’s propensity to move involuntarily over typical imaging timescales, obscuring the fine structure in the eye due to the resulting motion artifacts. However, advances in MRI technology help to mitigate such drawbacks, enabling the acquisition of high spatiotemporal resolution images with a variety of contrast mechanisms. This review aims to classify the MRI techniques used to date in clinical and preclinical ophthalmologic studies, describing the qualitative and quantitative information that may be extracted and how this may inform on ocular pathophysiology. PMID:23112569

  13. Clinical Applications of Magnetic Resonance Imaging

    PubMed Central

    Kumar, Alka; Montanera, Walter; Terbrugge, Karel G.; Willinsky, Robert; Fenton, Paul V.

    1992-01-01

    Magnetic resonance imaging (MRI) is a relatively new diagnostic imaging technique that has substantially affected the diagnosis of a multitude of diseases. It has become the imaging modality of choice for a number of pathologic processes, especially in the central nervous system. The authors discuss the clinical applications of MRI, its current status in radiologic investigations, and radiographic features of some of the common diseases of the central nervous system. ImagesFigure 1Figures 2-3Figure 4Figures 5-6Figure 7Figure 8Figure 9Figure 10Figure 11Figures 12-13 PMID:21229123

  14. Silicon Nanoparticles as Hyperpolarized Magnetic Resonance Imaging Agents

    E-print Network

    Silicon Nanoparticles as Hyperpolarized Magnetic Resonance Imaging Agents Jacob W. Aptekar,, Maja C-based biosensing, drug de- livery, and tissue engineering applications.10,11 For magnetic resonance imaging (MRI Chemical Society ABSTRACT Magnetic resonance imaging of hyperpolarized nuclei provides high image contrast

  15. A Penalized Likelihood Approach to Magnetic Resonance Image Reconstruction

    E-print Network

    A Penalized Likelihood Approach to Magnetic Resonance Image Reconstruction Vera L. Bulaevskaya of Minnesota #12;Summary Currently, images acquired via Magnetic Resonance Imaging (MRI) and functional Magnetic Resonance Imaging (fMRI) technology are reconstructed using the discrete inverse Fourier transform

  16. Genetically encoded reporters for hyperpolarized xenon magnetic resonance imaging

    E-print Network

    Genetically encoded reporters for hyperpolarized xenon magnetic resonance imaging Mikhail G Pines5,6, David V. Schaffer2,7 and Vikram S. Bajaj5,6 * Magnetic resonance imaging (MRI) enables high- netic resonance imaging (MRI) routinely delivers non-invasive images of anatomy at high resolution2

  17. MAGNETIC RESONANCE IMAGE VIEWING ``SCREEN REAL ESTATE'' PROBLEM

    E-print Network

    Atkins, M. Stella

    MAGNETIC RESONANCE IMAGE VIEWING AND THE ``SCREEN REAL ESTATE'' PROBLEM By Johanna van der Heyden B Degree: Master of Science Title of thesis: Magnetic Resonance Image Viewing and the ``Screen Real Estate of images on a computer screen. In particular, Magnetic Resonance Imaging (MRI) studies involve multiple

  18. Bioengineering 208: Magnetic Resonance Imaging Laboratory Winter 2007

    E-print Network

    California at San Diego, University of

    Bioengineering 208: Magnetic Resonance Imaging Laboratory Winter 2007 Lab 4- Week of 1/29 1. Off distortion to estimate the resonance offset of a point in the image. Find a portion of the image were inverted without the recon software's knowledge. These two images will have off resonance related

  19. Fetal Cerebral Magnetic Resonance Imaging Beyond Morphology.

    PubMed

    Jakab, András; Pogledic, Ivana; Schwartz, Ernst; Gruber, Gerlinde; Mitter, Christian; Brugger, Peter C; Langs, Georg; Schöpf, Veronika; Kasprian, Gregor; Prayer, Daniela

    2015-12-01

    The recent technological advancement of fast magnetic resonance imaging (MRI) sequences allowed the inclusion of diffusion tensor imaging, functional MRI, and proton MR spectroscopy in prenatal imaging protocols. These methods provide information beyond morphology and hold the key to improving several fields of human neuroscience and clinical diagnostics. Our review introduces the fundamental works that enabled these imaging techniques, and also highlights the most recent contributions to this emerging field of prenatal diagnostics, such as the structural and functional connectomic approach. We introduce the advanced image processing approaches that are extensively used to tackle fetal or maternal movement-related image artifacts, and which are necessary for the optimal interpretation of such imaging data. PMID:26614130

  20. Technical artifacts in magnetic resonance imaging.

    PubMed

    Yamanashi, W S; Wheatley, K K; Lester, P D; Anderson, D W

    1984-01-01

    Various artifacts of Magnetic Resonance Imaging (MRI) typically associated with currently available imaging techniques such as projection reconstruction and two-dimensional fourier transform (2D-FT) are described and illustrated. Examples of MRI artifacts were obtained with an imaging unit with a super conducting magnet operated at .15 Tesla and .27 Tesla with corresponding proton resonance frequency of 6.4 MHz and 11.25 MHz. The .15 Tesla images were obtained using projection reconstruction and the .27 Tesla using the 2D-FT method. Instrument related artifacts include those due to direct current (DC), projection, gradient offset, active shimming, phase encoding, and pulse sequencing. Other often encountered artifacts are related to the patient. These include those due to motion, ferromagnetic effect, and tissue contents. The cause of these artifacts and how (if possible) they may be eliminated or minimized is discussed. PMID:6514817

  1. Magnetic resonance imaging in Mexico

    NASA Astrophysics Data System (ADS)

    Rodriguez, A. O.; Rojas, R.; Barrios, F. A.

    2001-10-01

    MR imaging has experienced an important growth worldwide and in particular in the USA and Japan. This imaging technique has also shown an important rise in the number of MR imagers in Mexico. However, the development of MRI has followed a typical way of Latin American countries, which is very different from the path shown in the industrialised countries. Despite the fact that Mexico was one the very first countries to install and operate MR imagers in the world, it still lacks of qualified clinical and technical personnel. Since the first MR scanner started to operate, the number of units has grown at a moderate space that now sums up approximately 60 system installed nationwide. Nevertheless, there are no official records of the number of MR units operating, physicians and technicians involved in this imaging modality. The MRI market is dominated by two important companies: General Electric (approximately 51%) and Siemens (approximately 17.5%), the rest is shared by other five companies. According to the field intensity, medium-field systems (0.5 Tesla) represent 60% while a further 35% are 1.0 T or higher. Almost all of these units are in private hospitals and clinics: there is no high-field MR imagers in any public hospital. Because the political changes in the country, a new public plan for health care is still in the process and will be published soon this year. This plan will be determined by the new Congress. North American Free Trade Agreement (NAFTA) and president Fox. Experience acquired in the past shows that the demand for qualified professionals will grow in the new future. Therefore, systematic training of clinical and technical professionals will be in high demand to meet the needs of this technique. The National University (UNAM) and the Metropolitan University (UAM-Iztapalapa) are collaborating with diverse clinical groups in private facilities to create a systematic training program and carry out research and development in MRI

  2. Focal renal masses: magnetic resonance imaging

    SciTech Connect

    Choyke, P.L.; Kressel, H.Y.; Pollack, H.M.; Arger, P.M.; Axel, L.; Mamourian, A.C.

    1984-08-01

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

  3. Reducing Field Distortion in Magnetic Resonance Imaging

    NASA Technical Reports Server (NTRS)

    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. Surface Plasmon Resonance Imaging Measurements of Antibody Arrays for the

    E-print Network

    Surface Plasmon Resonance Imaging Measurements of Antibody Arrays for the Multiplexed Detection molecular weight protein biomarkers with surface plasmon resonance imaging (SPRI). A one methodology would be to use an optical method that can directly detect antigen binding. Surface plasmon

  5. Magnetic resonance imaging of pelvic floor dysfunction.

    PubMed

    Lalwani, Neeraj; Moshiri, Mariam; Lee, Jean H; Bhargava, Puneet; Dighe, Manjiri K

    2013-11-01

    Pelvic floor dysfunction is largely a complex problem of multiparous and postmenopausal women and is associated with pelvic floor or organ descent. Physical examination can underestimate the extent of the dysfunction and misdiagnose the disorders. Functional magnetic resonance (MR) imaging is emerging as a promising tool to evaluate the dynamics of the pelvic floor and use for surgical triage and operative planning. This article reviews the anatomy and pathology of pelvic floor dysfunction, typical imaging findings, and the current role of functional MR imaging. PMID:24210448

  6. [Nuclear magnetic resonance imaging. Clinical applications].

    PubMed

    Laval-Jeantet, M; Crooks, L E; Davis, P L; Kaufman, L; Margulis, A R

    1982-09-01

    Nuclear magnetic resonance (NMR) imaging is based on selective excitation of proton magnetic properties by means of a dual magnetic field. In the human body, NMR gives sectional images which represent hydrogen atom densities in the different tissues. The first results obtained in tomography of the brain, spinal cord, intrathoracic and abdominal organs and some vessels have been remarkable. The magnetic fields ans radiofrequency waves involved appear to be harmless. NMR imaging favourably compares with X-ray computerized tomography or with ultrasonography and will no doubt be increasingly used for its special qualities. PMID:6982457

  7. Bioengineering 208: Magnetic Resonance Imaging Laboratory Winter 2007

    E-print Network

    California at San Diego, University of

    Bioengineering 208: Magnetic Resonance Imaging Laboratory Winter 2007 SYLLABUS Week Lecture Lab 1 and non-CPMG echoes SPGR vs FLASH vs SSFP 4 Echo Planar Imaging Bandwidth anisotropy Off Resonance image from raw data Calculate slice profile from image data Calculate B1 map from image data Generate

  8. A Scalable Framework For Segmenting Magnetic Resonance Images

    E-print Network

    Hall, Lawrence O.

    A Scalable Framework For Segmenting Magnetic Resonance Images Prodip Hore, Lawrence O. Hall, Dmitry, accurate and fully automatic method of segmenting magnetic resonance images of the human brain a framework for auto- matically segmenting magnetic resonance images of the human brain. The framework

  9. Silicon Nanoparticles as Hyperpolarized Magnetic Resonance Imaging Agents

    E-print Network

    Walsworth, Ronald L.

    Silicon Nanoparticles as Hyperpolarized Magnetic Resonance Imaging Agents Jacob W. Aptekar,, Maja C-based biosensing, drug de- livery, and tissue engineering applications.10,11 For magnetic resonance imaging (MRI.1021/nn900996p © 2009 American Chemical Society ABSTRACT Magnetic resonance imaging of hyperpolarized

  10. Bioengineering 278: Magnetic Resonance Imaging Laboratory Winter 2014

    E-print Network

    California at San Diego, University of

    Bioengineering 278: Magnetic Resonance Imaging Laboratory Winter 2014 Lab 6 The goal of this week should contain 1 series capacitor to make it resonate. This configuration will support 2 resonant modes/R in the scanner, axial imaging plane. b. Coil axis oriented S/I in the scanner, axial image through middle of coil

  11. TENSOR BASED ANALYSIS OF DIFFUSION WEIGHTED MAGNETIC RESONANCE IMAGES

    E-print Network

    Atkins, M. Stella

    TENSOR BASED ANALYSIS OF DIFFUSION WEIGHTED MAGNETIC RESONANCE IMAGES by Yonas Tesfazghi 22, 2012 ii #12;Partial Copyright Licence #12;Abstract Diffusion Weighted Magnetic Resonance Imaging with Cartesian Tensors: a model known as Diffusion Tensor Magnetic Resonance Imaging (DT-MRI). We begin with 2nd

  12. 76 FR 58281 - Magnetic Resonance Imaging Safety; Public Workshop

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-20

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

  13. Improvements in Magnetic Resonance Imaging Excitation Pulse Design

    E-print Network

    Goyal, Vivek K

    Improvements in Magnetic Resonance Imaging Excitation Pulse Design by Adam Charles Zelinski of Doctor of Philosophy Abstract This thesis focuses on the design of magnetic resonance imaging (MRI) radio Resonance Imaging Excitation Pulse Design by Adam Charles Zelinski Submitted to the Department of Electrical

  14. Automated Affine Registration of First-Pass Magnetic Resonance Images

    E-print Network

    Acton, Scott

    Automated Affine Registration of First-Pass Magnetic Resonance Images Robert L. Janiczek, Andrew D, VA 22904 Abstract ­ Quantitative first-pass magnetic resonance (MR) imaging studies assist first-pass magnetic resonance (MR) imaging studies assist in characterizing the severity of ischemic

  15. Statistical Inference in Functional Magnetic Resonance Imaging Christopher R. Genovese

    E-print Network

    Statistical Inference in Functional Magnetic Resonance Imaging Christopher R. Genovese Carnegie­mail: genovese@stat.cmu.edu 1 #12; abstract Functional Magnetic Resonance Imaging (fMRI) is a new technique response. 2 #12; 1. Introduction Functional Magnetic Resonance Imaging (fMRI) is a rapidly developing tool

  16. Statistical Inference in Functional Magnetic Resonance Imaging Christopher R. Genovese

    E-print Network

    Genovese, Christopher

    Statistical Inference in Functional Magnetic Resonance Imaging Christopher R. Genovese Carnegie://www.stat.cmu.edu/ ~ genovese/ #12; abstract Functional Magnetic Resonance Imaging (fMRI) is a new technique for studying. Introduction Functional Magnetic Resonance Imaging (fMRI) is a rapidly developing tool that enables cognitive

  17. On the generation of sampling schemes for Magnetic Resonance Imaging.

    E-print Network

    Weiss, Pierre

    On the generation of sampling schemes for Magnetic Resonance Imaging. Claire Boyer Nicolas Chauffert Philippe Ciuciu Jonas Kahn§ Pierre Weiss¶ July 24, 2015 Abstract Magnetic resonance imaging (MRI 7 Conclusion 32 #12;3 1 Introduction Magnetic resonance imaging (MRI) is one of the flagship

  18. COMPETITIVE MIXTURE OF LOCAL LINEAR EXPERTS FOR MAGNETIC RESONANCE IMAGING

    E-print Network

    Slatton, Clint

    COMPETITIVE MIXTURE OF LOCAL LINEAR EXPERTS FOR MAGNETIC RESONANCE IMAGING By RUI YAN.1 Literature Review of Magnetic Resonance Imaging . . . . . . . . . . 1 1.1.1 History of MRI Reconstruction in Phased-Array MRI . . . . . . . . . 2 1.2 Magnetic Resonance Imaging Basics

  19. GEOMETRIC COMPUTATION OF HUMAN GYRIFICATION INDEXES FROM MAGNETIC RESONANCE IMAGES

    E-print Network

    GEOMETRIC COMPUTATION OF HUMAN GYRIFICATION INDEXES FROM MAGNETIC RESONANCE IMAGES By Shu Su Tonya Indexes from Magnetic Resonance Images Shu Su1 Tonya White 3,4,5,6 Marcus Schmidt 3 Chiu-Yen Kao 1 of human brains from magnetic resonance images (MRI). This approach is based on intrinsic 3D measurements

  20. Magnetic Resonance Imaging of Brain Function and Neurochemistry

    E-print Network

    Duong, Timothy Q.

    Magnetic Resonance Imaging of Brain Function and Neurochemistry KAMIL UGURBIL, DAE-SHIK KIM, TIM ANDERSEN, AND GREGOR ADRIANY Invited Paper In the past decade, magnetic resonance imaging (MRI) research approaches to map brain function. This capability, often referred to as functional magnetic resonance imaging

  1. Magnetic resonance imaging of rectal cancer.

    PubMed

    Ho, Mai-Lan; Liu, Judy; Narra, Vamsidhar

    2008-08-01

    Magnetic resonance imaging (MRI)is a useful modality for the evaluation of rectal cancer, providing superior anatomic/pathologic visualization when compared with endorectal ultrasound (EUS) and computed tomography (CT). Preoperative MRI is useful for tissue characterization and tumor staging, which determines the surgical approach and need for neoadjuvant/adjuvant therapy. Important prognostic factors include the circumferential resection margin (CRM), T and N stages, and extent of local invasion. Postoperative MRI to assess the extent of tumor recurrence enables early resection, which can greatly prolong survival. MRI criteria for local recurrence include T2 hyperintensity, early dynamic rim enhancement, and nodular morphology. Future research in MRI of rectal cancer is geared toward developing optimal imaging techniques including high-resolution MRI, whole-body scans, and parallel imaging; imaging of lymph nodes by MR lymphography; and response to therapy using diffusion/perfusion-weighted MR and functional imaging. PMID:20011416

  2. Enhancement of magnetic resonance imaging with metasurfaces

    E-print Network

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

    2015-01-01

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

  3. [Magnetic resonance imaging in thoracic diseases].

    PubMed

    Norès, J M; Monsegu, M H; Bergal, S; Ameille, J; Rémy, J M; Lacrosnière, L

    1994-10-01

    Most all the thoracic structures are visible with magnetic resonance imaging: the mediastin, the myocardium including the endocardium and the pericardium, the pulmonary parenchyma and hile and the pleural walls. In cases of mediastrinal masses, T1 images clearly delimit their relations with neighbouring organs and vessels. The intensity of the signal is compared with that of the muscles on T1 weighted images of the preceding sections and T2 weighted images of fat. Images of aneurysms and chronic dissections can be synchronized with the ECG allowing three-dimensional measurement of the size and thickness of the vessel walls. Thrombi or extension to other vessels can also be recognized. Small hilar tumours can be differentiated from vessels but the scanner is better for analyzing systematization and bronchial lesions. For lung tissue itself, magnetic resonance imaging can detect nodules greater than one centimeter in diameter, but the low proton density and respiratory movements hinder spatial resolution. MRI is indicated for localizing tumours situated anteriorly or posteriorly or at the apex and to identify parietal extension of peripheral cancers. Spinal, vascular, pericardial, diaphragmatic and lymph node metastases can be recognized. MRI is the noninvasive method of choice for evaluating left ventricular masse, intra and paracardiac mass studies and for investigating congenital and acquired cardiomyopathies. Technical advances have made it possible to evaluate myocardial perfusion and heart function. PMID:7984543

  4. On Image Registration In Magnetic Resonance Imaging School of Statistics, University of Minnesota

    E-print Network

    Qiu, Peihua

    On Image Registration In Magnetic Resonance Imaging Peihua Qiu School of Statistics, University.nguyen@tuebingen.mpg.de Abstract Image registration is used in many fields for mapping one image to another. In magnetic resonance introduce some commonly used image registration procedures and their applications in magnetic resonance

  5. In vivo nuclear magnetic resonance imaging

    NASA Technical Reports Server (NTRS)

    Leblanc, A.

    1986-01-01

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

  6. Diagnostic magnetic resonance imaging of the breast.

    PubMed

    Kilic, Fahrettin; Ogul, Hayri; Bayraktutan, Ummugulsum; Gumus, Hatice; Unal, Ozlem; Kantarci, Mecit; Yilmaz, M Halit

    2012-08-01

    Contrast enhanced breast magnetic resonance imaging is a modality that is frequently used into the breast radiologist's daily clinical practice. MRI examination should have optimal technical proficiency in order to attain diagnostic quality avoiding false positive and negative diagnoses. Furthermore, due to increasing usage fields of the examinations uniting with high sensitivity phenomenon, excessive usage and excision/interventional procedures are inevitable. Therefore, we hope to highlight the appropriate usage of the MRI technique and it's clinical applications. PMID:25610219

  7. New magnetic resonance imaging methods in nephrology

    PubMed Central

    Zhang, Jeff L.; Morrell, Glen; Rusinek, Henry; Sigmund, Eric; Chandarana, Hersh; Lerman, Lilach O.; Prasad, Pottumarthi Vara; Niles, David; Artz, Nathan; Fain, Sean; Vivier, Pierre H.; Cheung, Alfred K.; Lee, Vivian S.

    2013-01-01

    Established as a method to study anatomic changes, such as renal tumors or atherosclerotic vascular disease, magnetic resonance imaging (MRI) to interrogate renal function has only recently begun to come of age. In this review, we briefly introduce some of the most important MRI techniques for renal functional imaging, and then review current findings on their use for diagnosis and monitoring of major kidney diseases. Specific applications include renovascular disease, diabetic nephropathy, renal transplants, renal masses, acute kidney injury and pediatric anomalies. With this review, we hope to encourage more collaboration between nephrologists and radiologists to accelerate the development and application of modern MRI tools in nephrology clinics. PMID:24067433

  8. Magnetic resonance imaging. Application to family practice.

    PubMed Central

    Goh, R. H.; Somers, S.; Jurriaans, E.; Yu, J.

    1999-01-01

    OBJECTIVE: To review indications, contraindications, and risks of using magnetic resonance imaging (MRI) in order to help primary care physicians refer patients appropriately for MRI, screen for contraindications to using MRI, and educate patients about MRI. QUALITY OF EVIDENCE: Recommendations are based on classic textbooks, the policies of our MRI group, and a literature search using MEDLINE with the MeSH headings magnetic resonance imaging, brain, musculoskeletal, and spine. The search was limited to human, English-language, and review articles. Evidence in favour of using MRI for imaging the head, spine, and joints is well established. For cardiac, abdominal, and pelvic conditions, MRI has been shown useful for certain indications, usually to complement other modalities. MAIN MESSAGE: For demonstrating soft tissue conditions, MRI is better than computed tomography (CT), but CT shows bone and acute bleeding better. Therefore, patients with trauma or suspected intracranial bleeding should have CT. Tumours, congenital abnormalities, vascular structures, and the cervical or thoracic spine show better on MRI. Either modality can be used for lower back pain. Cardiac, abdominal, and pelvic abnormalities should be imaged with ultrasound or CT before MRI. Contraindications for MRI are mainly metallic implants or shrapnel, severe claustrophobia, or obesity. CONCLUSIONS: With the increasing availability of MRI scanners in Canada, better understanding of the indications, contraindications, and risks will be helpful for family physicians and their patients. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 PMID:10509224

  9. Imaging by electromagnetic induction with resonant circuits

    NASA Astrophysics Data System (ADS)

    Guilizzoni, Roberta; Watson, Joseph C.; Bartlett, Paul; Renzoni, Ferruccio

    2015-05-01

    A new electromagnetic induction imaging system is presented which is capable of imaging metallic samples of different conductivities. The system is based on a parallel LCR circuit made up of a cylindrical ferrite-cored coil and a capacitor bank. An AC current is applied to the coil, thus generating an AC magnetic field. This field is modified when a conductive sample is placed within the magnetic field, as a consequence of eddy current induction inside the sample. The electrical properties of the LCR circuit, including the coil inductance, are modified due to the presence of this metallic sample. Position-resolved measurements of these modifications should then allow imaging of conductive objects as well as enable their characterization. A proof-of-principle system is presented in this paper. Two imaging techniques based on Q-factor and resonant frequency measurements are presented. Both techniques produced conductivity maps of 14 metallic objects with different geometries and values of conductivity ranging from 0.54?106 to 59.77?106 S/m. Experimental results highlighted a higher sensitivity for the Q-factor technique compared to the resonant frequency one; the respective measurements were found to vary within the following ranges: ?Q=[-11,-2]%, ?f=[-0.3,0.7]%. The analysis of the images, conducted using a Canny edge detection algorithm, demonstrated the suitability of the Q-factor technique for accurate edge detection of both magnetic and non-magnetic metallic samples.

  10. Gastrointestinal imaging-practical magnetic resonance imaging approach

    PubMed Central

    Liu, Baodong; Ramalho, Miguel; AlObaidy, Mamdoh; Busireddy, Kiran K; Altun, Ersan; Kalubowila, Janaka; Semelka, Richard C

    2014-01-01

    Over the past two decades, advances in cross-sectional imaging such as computed tomography and magnetic resonance imaging (MRI) have dramatically changed the concept of gastrointestinal imaging. MR is playing an increasing role in the evaluation of gastrointestinal disorders. MRI combines the advantages of excellent soft-tissue contrast, noninvasiveness, functional information and lack of ionizing radiation. Furthermore, recent developments of MRI have led to improved spatial and temporal resolution as well as decreased motion artifacts. In this article we describe the technical aspects of gastrointestinal MRI and present a practical approach for a well-known spectrum of gastrointestinal disease processes. PMID:25170393

  11. MAGNETIC RESONANCE IMAGE RECONSTRUCTION FROM NON-EQUIDISTANTLY SAMPLED DATA

    E-print Network

    Adali, Tulay

    MAGNETIC RESONANCE IMAGE RECONSTRUCTION FROM NON-EQUIDISTANTLY SAMPLED DATA Ning Li' , Tulay Adalzl consider the problem of magnetic reso- nance (MR~'image reconstruction from non-uniformly sam- pled data resonance imaging (MRI) applications and can lead to image artifacts from patient motion during the scan

  12. Shape Based Segmentation of Anatomical Structures in Magnetic Resonance Images

    E-print Network

    Fisher III, John

    Shape Based Segmentation of Anatomical Structures in Magnetic Resonance Images Kilian M. Pohl1 constraints and image artifacts of Magnetic Resonance (MR) images. The detection of substructures is difficult probability estimation problem. We demonstrate the approach on 20 brain magnetic reso- nance images showing

  13. Towards Single Biomolecule Imaging via Optical Nanoscale Magnetic Resonance Imaging.

    PubMed

    Boretti, Alberto; Rosa, Lorenzo; Castelletto, Stefania

    2015-09-01

    Nuclear magnetic resonance (NMR) spectroscopy is a physical marvel in which electromagnetic radiation is charged and discharged by nuclei in a magnetic field. In conventional NMR, the specific nuclei resonance frequency depends on the strength of the magnetic field and the magnetic properties of the isotope of the atoms. NMR is routinely utilized in clinical tests by converting nuclear spectroscopy in magnetic resonance imaging (MRI) and providing 3D, noninvasive biological imaging. While this technique has revolutionized biomedical science, measuring the magnetic resonance spectrum of single biomolecules is still an intangible aspiration, due to MRI resolution being limited to tens of micrometers. MRI and NMR have, however, recently greatly advanced, with many breakthroughs in nano-NMR and nano-MRI spurred by using spin sensors based on an atomic impurities in diamond. These techniques rely on magnetic dipole-dipole interactions rather than inductive detection. Here, novel nano-MRI methods based on nitrogen vacancy centers in diamond are highlighted, that provide a solution to the imaging of single biomolecules with nanoscale resolution in-vivo and in ambient conditions. PMID:26113221

  14. Model-based reconstruction of magnetic resonance spectroscopic imaging

    E-print Network

    Chatnuntawech, Itthi

    2013-01-01

    Magnetic resonance imaging (MRI) is a medical imaging technique that is used to obtain images of soft tissue throughout the body. Since its development in the 1970s, MRI has gained tremendous importance in clinical practice ...

  15. TaskOriented Lossy Compression of Magnetic Resonance Images

    E-print Network

    Atkins, M. Stella

    Task­Oriented Lossy Compression of Magnetic Resonance Images by Mark Charles Anderson B.Sc. (Comp rates. Application of the new system to magnetic resonance images is shown to produce compression. Jacques Vaisey Supervisor Dr. Ze­Nian Li Examiner Date Approved: ii #12; Abstract Magnetic resonance

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

    E-print Network

    Hajimiri, Ali

    A Spectral-Scanning Magnetic Resonance Imaging (MRI) Integrated System Arjang Hassibi1,2 , Aydin to 250MHz for narrow-band MR spectroscopy. I. INTRODUCTION Scaling down magnetic resonance imaging (MRI of Texas at Austin, Austin, TX 78712, USA Abstract- An integrated spectral-scanning magnetic resonance

  17. Bioengineering 278: Magnetic Resonance Imaging Laboratory Winter 2010

    E-print Network

    California at San Diego, University of

    Bioengineering 278: Magnetic Resonance Imaging Laboratory Winter 2010 Lab 4 1. EPI offsets. The simulation that looks the most like the blurred image indicates the true resonance offset. In this exercise, you will observe and correct the effects of time shifts and resonance offset in EPI. Place

  18. IEEE TRANSACTIONS ON MEDICAL IMAGING, VOL. , NO. , 1 Synthetic Magnetic Resonance Imaging Revisited

    E-print Network

    Maitra, Ranjan

    IEEE TRANSACTIONS ON MEDICAL IMAGING, VOL. , NO. , 1 Synthetic Magnetic Resonance Imaging Revisited Ranjan Maitra and John J. Riddles Abstract--Synthetic magnetic resonance (MR) imaging is an approach MAGNETIC Resonance Imaging (MRI) is a radiologic tool ([1], [2], [3]) used to visualize tissue structure

  19. Nuclear magnetic resonance imaging of the kidney

    SciTech Connect

    Hricak, H.; Crooks, L.; Sheldon, P.; Kaufman, L.

    1983-02-01

    The role of nuclear magnetic resonance (NMR) imaging of the kidney was analyzed in 18 persons (6 normal volunteers, 3 patients with pelvocaliectasis, 2 with peripelvic cysts, 1 with renal sinus lipomatosis, 3 with renal failure, 1 with glycogen storage disease, and 2 with polycystic kidney disease). Ultrasound and/or computed tomography (CT) studies were available for comparison in every case. In the normal kidney distinct anatomical structures were clearly differentiated by NMR. The best anatomical detail ws obtained with spin echo (SE) imaging, using a pulse sequence interval of 1,000 msec and an echo delay time of 28 msec. However, in the evaluation of normal and pathological conditions, all four intensity images (SE 500/28, SE 500/56, SE 1,000/28, and SE 1,000/56) have to be analyzed. No definite advantage was found in using SE imaging with a pulse sequence interval of 1,500 msec. Inversion recovery imaging enhanced the differences between the cortex and medulla, but it had a low signal-to-noise level and, therefore, a suboptimal overall resolution. The advantages of NMR compared with CT and ultrasound are discussed, and it is concluded that NMR imaging will prove to be a useful modality in the evaluation of renal disease.

  20. ASA monitoring standards and magnetic resonance imaging.

    PubMed

    Jorgensen, N H; Messick, J M; Gray, J; Nugent, M; Berquist, T H

    1994-12-01

    Some patients, often because of age or altered mental state, require general anesthesia or monitored anesthesia care and sedation if adequate magnetic resonance imaging (MRI) is to be accomplished. This study evaluated whether patients can be monitored during MRI with 1.5-tesla scanners in a manner which complies with ASA monitoring standards without causing degradation of image quality. Ten volunteers were scanned in the MRI without sedation. Monitors meeting ASA standards were placed and electronic artifact produced by the magnetic resonance (MR) scanner was evaluated, after which two scans of the head and two of the chest were performed. One of each pair of scans was obtained with the monitors functioning and one with them turned off. Four radiologists, blinded as to whether the monitors were turned on or off, independently evaluated the 20 pairs of scans. Differences in diagnostic quality and image degradation between the scans were evaluated and scores assigned. All monitors functioned appropriately during the scans, with the exception of the electrocardiogram (ECG) which was grossly distorted to the extent that only ventricular rate could be evaluated. None of the head or body scans was nondiagnostic; however, images with the monitors off were of better quality overall than with them on. Two types of noise were generated and are described. During the head scans, three of seven monitoring combinations caused degradation of the images, while four were judged clinically adequate. During the body scans, two of six monitoring combinations created noticeable noise, while four introduced no significant noise. Ungated cardiac scans were nondiagnostic.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7978439

  1. Tools for cardiovascular magnetic resonance imaging

    PubMed Central

    Krishnamurthy, Ramkumar; Cheong, Benjamin

    2014-01-01

    In less than fifteen years, as a non-invasive imaging option, cardiovascular MR has grown from a being a mere curiosity to becoming a widely used clinical tool for evaluating cardiovascular disease. Cardiovascular magnetic resonance imaging (CMRI) is now routinely used to study myocardial structure, cardiac function, macro vascular blood flow, myocardial perfusion, and myocardial viability. For someone entering the field of cardiac MR, this rapid pace of development in the field of CMRI might make it difficult to identify a cohesive starting point. In this brief review, we have attempted to summarize the key cardiovascular imaging techniques that have found widespread clinical acceptance. In particular, we describe the essential cardiac and respiratory gating techniques that form the backbone of all cardiovascular imaging methods. It is followed by four sections that discuss: (I) the gradient echo techniques that are used to assess ventricular function; (II) black-blood turbo spin echo (SE) methods used for morphologic assessment of the heart; (III) phase-contrast based techniques for the assessment of blood flow; and (IV) CMR methods for the assessment of myocardial ischemia and viability. In each section, we briefly summarize technical considerations relevant to the clinical use of these techniques, followed by practical information for its clinical implementation. In each of those four areas, CMRI is considered either as the benchmark imaging modality against which the diagnostic performance of other imaging modalities are compared against, or provides a complementary capability to existing imaging techniques. We have deliberately avoided including cutting-edge CMR imaging techniques practiced at few academic centers, and restricted our discussion to methods that are widely used and are likely to be available in a clinical setting. Our hope is that this review would propel an interested reader toward more comprehensive reviews in the literature. PMID:24834409

  2. Tools for cardiovascular magnetic resonance imaging.

    PubMed

    Krishnamurthy, Ramkumar; Cheong, Benjamin; Muthupillai, Raja

    2014-04-01

    In less than fifteen years, as a non-invasive imaging option, cardiovascular MR has grown from a being a mere curiosity to becoming a widely used clinical tool for evaluating cardiovascular disease. Cardiovascular magnetic resonance imaging (CMRI) is now routinely used to study myocardial structure, cardiac function, macro vascular blood flow, myocardial perfusion, and myocardial viability. For someone entering the field of cardiac MR, this rapid pace of development in the field of CMRI might make it difficult to identify a cohesive starting point. In this brief review, we have attempted to summarize the key cardiovascular imaging techniques that have found widespread clinical acceptance. In particular, we describe the essential cardiac and respiratory gating techniques that form the backbone of all cardiovascular imaging methods. It is followed by four sections that discuss: (I) the gradient echo techniques that are used to assess ventricular function; (II) black-blood turbo spin echo (SE) methods used for morphologic assessment of the heart; (III) phase-contrast based techniques for the assessment of blood flow; and (IV) CMR methods for the assessment of myocardial ischemia and viability. In each section, we briefly summarize technical considerations relevant to the clinical use of these techniques, followed by practical information for its clinical implementation. In each of those four areas, CMRI is considered either as the benchmark imaging modality against which the diagnostic performance of other imaging modalities are compared against, or provides a complementary capability to existing imaging techniques. We have deliberately avoided including cutting-edge CMR imaging techniques practiced at few academic centers, and restricted our discussion to methods that are widely used and are likely to be available in a clinical setting. Our hope is that this review would propel an interested reader toward more comprehensive reviews in the literature. PMID:24834409

  3. Diagnostic Magnetic Resonance Imaging of the Breast

    PubMed Central

    Kilic, Fahrettin; Ogul, Hayri; Bayraktutan, Ummugulsum; Gumus, Hatice; Unal, Ozlem; Kantarci, Mecit; Yilmaz, M. Halit

    2012-01-01

    Contrast enhanced breast magnetic resonance imaging is a modality that is frequently used into the breast radiologist’s daily clinical practice. MRI examination should have optimal technical proficiency in order to attain diagnostic quality avoiding false positive and negative diagnoses. Furthermore, due to increasing usage fields of the examinations uniting with high sensitivity phenomenon, excessive usage and excision/interventional procedures are inevitable. Therefore, we hope to highlight the appropriate usage of the MRI technique and it’s clinical applications. PMID:25610219

  4. Magnetic resonance imaging of pelvic floor disorders.

    PubMed

    Khatri, Gaurav

    2014-08-01

    Physical examination alone is often inadequate for evaluation of pelvic floor dysfunction. Magnetic resonance imaging (MRI) is a robust modality that can provide high-quality anatomic and functional evaluation of the pelvic floor. Although lack of standardized technique and radiologist inexperience may be relative deterrents in universal acceptance of pelvic floor MRI, the role of MRI is increasing as it is technically feasible on most magnets and offers some advantages over the traditional fluoroscopic defecography. This review focuses on the technical and interpretational aspects of anatomic and functional pelvic floor MRI. PMID:25099563

  5. Cardiac imaging using gated magnetic resonance

    SciTech Connect

    Lanzer, P.; Botvinick, E.H.; Schiller, N.B.

    1984-01-01

    To overcome the limitations of magnetic resonance (MR) cardiac imaging using nongated data acquisition, three methods for acquiring a gating signal, which could be applied in the presence of a magnetic field, were tested; an air-filled plethysmograph, a laser-Doppler capillary perfusion flowmeter, and an electrocardiographic gating device. The gating signal was used for timing of MR imaging sequences (IS). Application of each gating method yielded significant improvements in structural MR image resolution of the beating heart, although with both plethysmography and laser-Doppler velocimetry it was difficult to obtain cardiac images from the early portion of the cardiac cycle due to an intrinsic delay between the ECG R wave and peripheral detection of the gating signal. Variations in the temporal relationship between the R wave and plethysmographic and laser-Doppler signals produced inconsistencies in the timing of IS. Since the ECG signal is virtually free of these problems, the preferable gating technique is IS synchronization with an electrocardiogram. The gated images acquired with this method provide sharp definition of internal cardiac morphology and can be temporarily referenced to end diastole and end systole or intermediate points.

  6. Concentric Förster resonance energy transfer imaging.

    PubMed

    Wu, Miao; Algar, W Russ

    2015-08-18

    Concentric Förster resonance energy transfer (cFRET) configurations based on semiconductor quantum dots (QDs) are promising probes for biological sensing because they offer multiplexing capability in a single vector with robust ratiometric detection by exploiting a network of FRET pathways. To expand the scope and utility of cFRET probes, it is necessary to develop and validate cFRET imaging methodology. In this technical note, we present such a methodology using a protease-sensitive cFRET configuration that comprises a green-emitting QD, Alexa Fluor 555 (A555), and Alexa Fluor 647 (A647). Photoluminescence (PL) images were acquired with three filter-based emission channels to permit measurement of A555/QD and A647/QD PL ratios. With reference to calibration samples, these PL ratios were used to calculate quantitative progress curves for proteolytic activity in regions of interest in the acquired images. Importantly, the imaging methodology reproduces quantitative results obtained with a monochromator-based fluorescence plate reader. Spatiotemporal resolution is demonstrated by tracking the activity of two prototypical proteases, trypsin and chymotrypsin, as they diffuse down the length of a capillary. This methodology is expected to enable the future use of cFRET probes for cellular sensing and other imaging assays. PMID:26214686

  7. Wavelets and functional magnetic resonance imaging of the human brain

    E-print Network

    Breakspear, Michael

    Wavelets and functional magnetic resonance imaging of the human brain Ed Bullmore,a,* Jalal Fadili, such as functional magnetic resonance images of the human brain, which often demonstrate scale invariant or fractal Breakspeare a Brain Mapping Unit and Wolfson Brain Imaging Centre, University of Cambridge, Addenbrooke

  8. In vivo nuclear magnetic resonance imaging

    NASA Technical Reports Server (NTRS)

    Leblanc, A.; Evans, H.; Bryan, R. N.; Johnson, P.; Schonfeld, E.; Jhingran, S. G.

    1984-01-01

    A number of physiological changes have been demonstrated in bone, muscle and blood after exposure of humans and animals to microgravity. Determining mechanisms and the development of effective countermeasures for long duration space missions is an important NASA goal. The advent of tomographic nuclear magnetic resonance imaging (NMR or MRI) gives NASA a way to greatly extend early studies of this phenomena in ways not previously possible; NMR is also noninvasive and safe. NMR provides both superb anatomical images for volume assessments of individual organs and quantification of chemical/physical changes induced in the examined tissues. The feasibility of NMR as a tool for human physiological research as it is affected by microgravity is demonstrated. The animal studies employed the rear limb suspended rat as a model of mucle atrophy that results from microgravity. And bedrest of normal male subjects was used to simulate the effects of microgravity on bone and muscle.

  9. Magnetic resonance imaging after exposure to microgravity

    NASA Technical Reports Server (NTRS)

    Leblanc, Adrian

    1993-01-01

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

  10. [Modern magnetic resonance imaging of the liver].

    PubMed

    Hedderich, D M; Weiss, K; Maintz, D; Persigehl, T

    2015-12-01

    Magnetic resonance imaging (MRI) of the liver has become an essential tool in the radiological diagnostics of both focal and diffuse diseases of the liver and is subject to constant change due to technological progress. Recently, important improvements could be achieved by innovations regarding MR hardware, sequences and postprocessing methods. The diagnostic spectrum of MRI could be broadened particularly due to new examination sequences, while at the same time scanning time could be shortened and image quality has been improved. The aim of this article is to explain both the technological background and the clinical application of recent MR sequence developments and to present the scope of a modern MRI protocol for the liver. PMID:26628259

  11. Magnetic Resonance Imaging Methods in Soil Science

    NASA Astrophysics Data System (ADS)

    Pohlmeier, A.; van Dusschoten, D.; Blümler, P.

    2009-04-01

    Magnetic Resonance Imaging (MRI) is a powerful technique to study water content, dynamics and transport in natural porous media. However, MRI systems and protocols have been developed mainly for medical purposes, i.e. for media with comparably high water contents and long relaxation times. In contrast, natural porous media like soils and rocks are characterized by much lower water contents, typically 0 < theta < 0.4, and much faster T1 and T2 relaxation times. So, the usage of standard medical scanners and protocols is of limited benefit. Three strategies can be applied for the monitoring of water contents and dynamics in natural porous media: i) Dedicated high-field scanners (with vertical bore) allowing stronger gradients and faster switching so that shorter echo times can be realized. ii) Special measurement sequences using ultrashort rf- and gradient-pulses like single point imaging derivates (SPI, SPRITE)(1) and multi-echo methods, which monitor series of echoes and allow for extrapolation to zero time(2). Hence, the loss of signal during the first echo period may be compensated to determine the initial magnetization (= water content) as well as relaxation time maps simultaneously. iii) Finally low field( < 1T) scanners also provide longer echo times and hence detect larger fractions of water, since the T2 relaxation time of water in most porous media increases with decreasing magnetic field strength(3). In the presentation examples for all three strategies will be given. References 1) Pohlmeier et al. Vadose Zone J. 7, 1010-1017 (2008) 2) Edzes et al., Magn. Res. Imag. 16, 185-196 (1998) 3) Raich H, and Blümler P, Concepts in Magn. Reson. B 23B, 16-25 (2004) 4) Pohlmeier et al. Magn. Res. Imag. doi:10.1016/j.mri.2008.06.007 (2008)

  12. Massive subchorionic thrombosis followed by magnetic resonance imaging.

    PubMed

    Himoto, Yuki; Okumura, Ryosuke; Tsuji, Natsuki; Nagano, Tadayoshi; Fujimoto, Masakazu; Yamaoka, Toshihide; Kohno, Shigene

    2012-01-01

    Massive subchorionic thrombosis is a rare condition, defined as a large thrombus confined to the subchorionic space. It is associated with poor perinatal prognosis. However, prenatal diagnosis by ultrasonography is often difficult. We report a case of massive subchorionic thrombosis developing dermatomyositis after the delivery, followed by magnetic resonance imaging. Moreover, we review other 4 cases assessed with magnetic resonance imaging. Magnetic resonance imaging is very useful for confirmation of diagnosis and follow-up in combination with ultrasonography. PMID:22592619

  13. Magnetic Resonance Imaging in Pediatric Pulmonary Hypertension

    PubMed Central

    Olgunturk, Rana; Cevik, Ayhan; Terlemez, Semiha; Kacar, Emre; Oner, Yusuf Ali

    2015-01-01

    The present study aims to determine the efficacy and reliability of cardiovascular magnetic resonance imaging in establishing the diagnosis and prognosis of pulmonary hypertension in children. This is a retrospective comparison of 25 children with pulmonary hypertension and a control group comprising 19 healthy children. The diagnosis of pulmonary hypertension was made when the mean pulmonary artery pressure was ?25 mmHg by catheter angiography. The children with pulmonary hypertension had significantly lower body mass indices than did the healthy children (P=0.048). In addition, the children with pulmonary hypertension had significantly larger main pulmonary artery diameters and ascending aortic diameters (both P=0.001) but statistically similar ratios of main pulmonary artery diameter-to-ascending aortic diameter. If the main pulmonary artery diameter was ?25 mm, pediatric pulmonary hypertension was diagnosed with 72% sensitivity and 84% specificity. In the event that the ratio of main pulmonary artery diameter-to-ascending aorta diameter was ?1, pediatric pulmonary hypertension was diagnosed with 60% sensitivity and 53% specificity. When compared with children who had New York Heart Association functional class II pulmonary hypertension, the children with functional class III pulmonary hypertension had significantly larger main (P=0.046), right (P=0.036), and left (P=0.003) pulmonary arteries. Cardiovascular magnetic resonance imaging is useful in the diagnosis of children with pulmonary hypertension. Pediatric pulmonary hypertension can be diagnosed with high sensitivity and specificity when the main pulmonary artery diameter measures ?25 mm. PMID:26175631

  14. Parallel Magnetic Resonance Imaging Using Compressed Sensing Ali Bilgina,b*

    E-print Network

    Bilgin, Ali

    Parallel Magnetic Resonance Imaging Using Compressed Sensing Ali Bilgina,b* , Yookyung Kima Although magnetic resonance imaging (MRI) is routinely used in clinical practice, long acquisition times independent utilization of each technique. Keywords: magnetic resonance imaging, parallel imaging, compressed

  15. Postinfectious Encephalitis A Coregistered SPECT and Magnetic Resonance Imaging

    E-print Network

    Itti, Laurent

    Postinfectious Encephalitis A Coregistered SPECT and Magnetic Resonance Imaging Study EMMANUEL ITTI remains uncertain. Key Words: Arenavirus, Brain SPECT, Coregistration, Encephalitis. References 1. Itti L

  16. Methods for chemical exchange saturation transfer magnetic resonance imaging

    E-print Network

    Scheidegger, Rachel Nora

    2013-01-01

    Chemical exchange saturation transfer (CEST) is a relatively new magnetic resonance imaging (MRI) acquisition technique that generates contrast dependent on tissue microenvironment, such as protein concentration and ...

  17. Magnetic resonance imaging in glenohumeral instability

    PubMed Central

    Jana, Manisha; Gamanagatti, Shivanand

    2011-01-01

    The glenohumeral joint is the most commonly dislocated joint of the body and anterior instability is the most common type of shoulder instability. Magnetic resonance (MR) imaging, and more recently, MR arthrography, have become the essential investigation modalities of glenohumeral instability, especially for pre-procedure evaluation before arthroscopic surgery. Injuries associated with glenohumeral instability are variable, and can involve the bones, the labor-ligamentous components, or the rotator cuff. Anterior instability is associated with injuries of the anterior labrum and the anterior band of the inferior glenohumeral ligament, in the form of Bankart lesion and its variants; whereas posterior instability is associated with reverse Bankart and reverse Hill-Sachs lesion. Multidirectional instability often has no labral pathology on imaging but shows specific osseous changes such as increased chondrolabral retroversion. This article reviews the relevant anatomy in brief, the MR imaging technique and the arthrographic technique, and describes the MR findings in each type of instability as well as common imaging pitfalls. PMID:22007285

  18. Bioengineering/Radiology 278: Magnetic Resonance Imaging Laboratory Winter 2010

    E-print Network

    California at San Diego, University of

    Bioengineering/Radiology 278: Magnetic Resonance Imaging Laboratory Winter 2010 Syllabus Week and reconstruct image from raw data Calculate B1 map from image data Understand the prescan process 2 2D spinwarp pulse sequence K-space Image contrast: T1, T2, PD 2D spinwarp imaging parameters Generate T1, T2, and PD

  19. Bioengineering/Radiology 278: Magnetic Resonance Imaging Laboratory Winter 2011

    E-print Network

    California at San Diego, University of

    Bioengineering/Radiology 278: Magnetic Resonance Imaging Laboratory Winter 2011 Syllabus Week image from raw data Calculate B1 map from image data Understand the prescan process 2 2D spinwarp pulse sequence K-space Image contrast: T1, T2, PD 2D spinwarp imaging parameters Generate T1, T2, and PD maps 3

  20. Elbow magnetic resonance imaging: imaging anatomy and evaluation.

    PubMed

    Hauptfleisch, Jennifer; English, Collette; Murphy, Darra

    2015-04-01

    The elbow is a complex joint. Magnetic resonance imaging (MRI) is often the imaging modality of choice in the workup of elbow pain, especially in sports injuries and younger patients who often have either a history of a chronic repetitive strain such as the throwing athlete or a distinct traumatic injury. Traumatic injuries and alternative musculoskeletal pathologies can affect the ligaments, musculotendinous, cartilaginous, and osseous structures of the elbow as well as the 3 main nerves to the upper limb, and these structures are best assessed with MRI.Knowledge of the complex anatomy of the elbow joint as well as patterns of injury and disease is important for the radiologist to make an accurate diagnosis in the setting of elbow pain. This chapter will outline elbow anatomy, basic imaging parameters, compartmental pathology, and finally applications of some novel MRI techniques. PMID:25835585

  1. Single-Shot Magnetic Resonance Spectroscopic Imaging with Partial Parallel Imaging

    E-print Network

    Single-Shot Magnetic Resonance Spectroscopic Imaging with Partial Parallel Imaging Stefan Posse,1; spectral quantification Ultra­high-speed magnetic resonance spectroscopic imag- ing (MRSI) with acquisition,2* Ricardo Otazo,2 Shang-Yueh Tsai,3 Akio Ernesto Yoshimoto,2 and Fa-Hsuan Lin4,5,6 A magnetic resonance

  2. In vivo Off-Resonance Saturation Magnetic Resonance Imaging of AvB3-Targeted Superparamagnetic Nanoparticles

    E-print Network

    Gao, Jinming

    #12;In vivo Off-Resonance Saturation Magnetic Resonance Imaging of AvB3-Targeted Superparamagnetic of Texas Southwestern Medical Center, Dallas, Texas Abstract Magnetic resonance imaging is a powerful mechanisms and imaging probes have been actively pursued for cancer molecular imaging by magnetic resonance

  3. Magnetic resonance spectroscopic imaging using parallel transmission at 7T

    E-print Network

    Gagoski, Borjan Aleksandar

    2011-01-01

    Conventional magnetic resonance spectroscopic imaging (MRSI), also known as phase-encoded (PE) chemical shift imaging (CSI), suffers from both low signal-to-noise ratio (SNR) of the brain metabolites, as well as inflexible ...

  4. Designing and characterizing hyperpolarizable silicon nanoparticles for magnetic resonance imaging

    E-print Network

    Anahtar, Melis Nuray

    2008-01-01

    Magnetic Resonance Imaging (MRI) is one of the most powerful noninvasive tools for diagnosing human disease, but its utility is limited because current contrast agents are ineffective when imaging air-tissue interfaces, ...

  5. [Value of magnetic resonance imaging in myeloma].

    PubMed

    Bellaïche, L; Laredo, J D

    1994-02-19

    Magnetic resonance imagery (MRI) of the spinal cord has become a standard method and its diagnostic and prognostic power in multiple myeloma has been widely demonstrated. Before treatment, MRI reveals two basic types of abnormalities yielding focal and diffuse signals. Focal lesions are seen as localized hyposignals on spin echo T1 sequences (SET1) and are enhanced by injection of gadolinium and changed to hypersignals in T2 weighted sequences. These images identify nodular tumoural masses. Diffuse lesions are seen most often as homogeneous SET1 images with an intensity similar to the vertebral body. This type of image is not specific of tumoural infiltration and can be benign in nature. The second type of diffuse signal is often called a "salt and pepper" image due to the juxtaposition of multiple hyposignals (suspected tumoural tissue) and hypersignals (fat tissue). We have observed this type of image in 27% of our series of multiple myelomas. The capacity of MRI to detect myelomas located in bone tissue is much greater than conventional radiography of the spine and is particularly sensitive to expansive tumoural lesions threatening the cord. MRI should always be performed as part of the initial work-up even in the absence of clinical signs. There is a good correlation between MRI of focal tumours and the biological response to treatment, although other biological markers may be more precise and easier to obtain. MRI can also be used to differentiate between benign monoclonal gammapathy and multiple myeloma, particularly in cases where there is a disagreement between the clinical and laboratory data. We have also studied MRI in solitary plasmacytomas of the spine. PMID:8208689

  6. TOPICAL REVIEW: Endovascular interventional magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Bartels, L. W.; Bakker, C. J. G.

    2003-07-01

    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.

  7. Bachelor of Science, Radiologic Sciences, Magnetic Resonance Imaging Emphasis, Name ID# Date

    E-print Network

    Barrash, Warren

    Bachelor of Science, Radiologic Sciences, Magnetic Resonance Imaging Emphasis, 2012-2013 Name ID Resonance Imaging I RADSCI 440L Principles of Magnetic Resonance Imaging I Lab RADSCI 441 Procedural Case Studies in Magnetic Resonance Imaging I RADSCI 442 Principles of Magnetic Resonance Imaging II RADSCI 442L

  8. Bachelor of Science, Radiologic Sciences, Magnetic Resonance Imaging Emphasis, Name ID# Date

    E-print Network

    Barrash, Warren

    Bachelor of Science, Radiologic Sciences, Magnetic Resonance Imaging Emphasis, 2013-2014 Name ID Resonance Imaging I RADSCI 440L Principles of Magnetic Resonance Imaging I Lab RADSCI 441 Procedural Case Studies in Magnetic Resonance Imaging I RADSCI 442 Principles of Magnetic Resonance Imaging II RADSCI 442L

  9. Bachelor of Science, Radiologic Sciences, Magnetic Resonance Imaging Emphasis, Name ID# Date

    E-print Network

    Barrash, Warren

    Bachelor of Science, Radiologic Sciences, Magnetic Resonance Imaging Emphasis, 2014-2015 Name ID Resonance Imaging I RADSCI 440L Principles of Magnetic Resonance Imaging I Lab RADSCI 441 Procedural Case Studies in Magnetic Resonance Imaging I RADSCI 442 Principles of Magnetic Resonance Imaging II RADSCI 442L

  10. Surface Plasmon Resonance of Nanoparticles and Applications in Imaging

    E-print Network

    Ammari, Habib

    Surface Plasmon Resonance of Nanoparticles and Applications in Imaging Habib Ammari Youjun Deng plasmon resonance of nanoparticles. Using layer potential techniques associated with the full Maxwell and absorption enhancements by plasmon resonant nanoparticles. We study both the cases of a single and multiple

  11. Imaging inflammation in stroke using magnetic resonance imaging.

    PubMed

    Chauveau, F; Cho, T H; Berthezène, Y; Nighoghossian, N; Wiart, M

    2010-11-01

    Stroke is the third leading cause of death, after myocardial infarction and cancer, and the leading cause of permanent disability in Western countries. Although anti-inflammatory drugs have shown very promising results in preclinical rodent studies, they appeared to be ineffective against stroke in clinical trials. In this context, non-invasive detection of inflammatory cells after brain ischemia could be helpful (i) to select patients who may benefit from anti-inflammatory treatment, and/or (ii) to target an adequate individualized therapeutic time window. Magnetic resonance imaging (MRI) coupled with injection of iron oxide nanoparticles, a contrast agent taken up by macrophages ex vivo and in vivo, appears to be a promising tool for this purpose. This review focuses on the use of this technique to image inflammation in pre-clinical and clinical studies of stroke. Despite current limitations, MRI of inflammation may become an important tool for the investigation of novel ischemic stroke therapeutics targeting inflammation. PMID:20979930

  12. Burn injury by nuclear magnetic resonance imaging.

    PubMed

    Eising, Ernst G; Hughes, Justin; Nolte, Frank; Jentzen, Walter; Bockisch, Andreas

    2010-01-01

    Nuclear magnetic resonance imaging has become a standard diagnostic procedure in clinical medicine and is well known to have hazards for patients with pacemaker or metallic foreign bodies. Compared to CT, the frequency of MRI examinations is increasing due to the missing exposure of the patients by X-rays. Furthermore, high-field magnetic resonance tomograph (MRT) with 3 T has entered clinical practice, and 7-T systems are installed in multiple scientific institutions. On the other hand, the possibility of burn injuries has been reported only in very few cases. Based on a clinical finding of a burn injury in a 31-year-old male patient during a routine MRI of the lumbar spine with standard protocol, the MR scanner was checked and the examination was simulated in an animal model. The patient received a third-degree burn injury of the skin of the right hand and pelvis in a small region of skin contact. The subsequent control of the MRI scanner indicated no abnormal values for radiofrequency (RF) and power. In the subsequent animal experiment, comparable injuries could only be obtained by high RF power in a microwave stove. It is concluded that 'tissue loops' resulting from a contact between hand and pelvis must be avoided. With regard to forensic aspects, the need to inform patients of such a minimal risk can be avoided if the patients are adequately positioned using an isolating material between the hands and pelvis. These facts must be emphasized more in the future, if high-field MRI with stronger RF gradients is available in routine imaging. PMID:20630342

  13. Long-Range Surface Plasmon Resonance Imaging for Bioaffinity Sensors

    E-print Network

    Long-Range Surface Plasmon Resonance Imaging for Bioaffinity Sensors Alastair W. Wark, Hye Jin Lee A novel bioaffinity sensor based on surface plasmon resonance (SPR) imaging measurements of a multiple- layered structure that supports the generation of long- range surface plasmons (LRSPs) at the water

  14. Surface Plasmon Resonance Imaging Studies of Protein-Carbohydrate Interactions

    E-print Network

    Surface Plasmon Resonance Imaging Studies of Protein-Carbohydrate Interactions Emily A. Smith; E-mail: corn@chem.wisc.edu; kiessling@chem.wisc.edu Abstract: Carbohydrate arrays fabricated on gold films were used to study carbohydrate-protein interactions with surface plasmon resonance (SPR) imaging

  15. Registration and Analysis of Myocardial Perfusion Magnetic Resonance Images

    E-print Network

    on the presented methods. Data from 10 patients with acute myocardial infarction is provided for this pur- poseRegistration and Analysis of Myocardial Perfusion Magnetic Resonance Images Hildur ´Olafsd This thesis presents the registration and analysis of myocardial perfusion mag- netic resonance images

  16. Bioengineering 278: Magnetic Resonance Imaging Laboratory Winter 2012

    E-print Network

    California at San Diego, University of

    Bioengineering 278: Magnetic Resonance Imaging Laboratory Winter 2012 Lab 5 EPI. In this lab, you will observe and correct the effects of time shifts and resonance offset in EPI. Place a phantom supports both EPI and spiral image acquisition. Prescribe a single axial slice with 64x64 resolution, spin

  17. Bioengineering 278: Magnetic Resonance Imaging Laboratory Winter 2014

    E-print Network

    California at San Diego, University of

    Bioengineering 278: Magnetic Resonance Imaging Laboratory Winter 2014 Lab 4 1. EPI. In this lab, you will observe Nyquist ghosts and resonance offset effects in EPI. Prescribe a spin echo EPI lines have already been reversed. Reconstruct the image by 2D FT. Unless you are super lucky

  18. Small Animal Imaging with Magnetic Resonance Microscopy

    PubMed Central

    Driehuys, Bastiaan; Nouls, John; Badea, Alexandra; Bucholz, Elizabeth; Ghaghada, Ketan; Petiet, Alexandra; Hedlund, Laurence W.

    2009-01-01

    Small animal magnetic resonance microscopy (MRM) has evolved significantly from testing the boundaries of imaging physics to its expanding use today as a tool in non-invasive biomedical investigations. This review is intended to capture the state-of-the-art in MRM for scientists who may be unfamiliar with this modality, but who want to apply its capabilities to their research. We therefore include a brief review of MR concepts and methods of animal handling and support before covering a range of MRM applications including the heart, lung, brain, and the emerging field of MR histology. High-resolution anatomical imaging reveals increasingly exquisite detail in healthy animals and subtle architectural aberrations that occur in genetically altered models. Resolution of 100 µm in all dimensions is now routinely attained in living animals, and 10 µm3 is feasible in fixed specimens. Such images almost rival conventional histology while allowing the object to be viewed interactively in any plane. MRM is now increasingly used to provide functional information in living animals. Images of the beating heart, breathing lung, and functioning brain can be recorded. While clinical MRI focuses on diagnosis, MRM is used to reveal fundamental biology or to non-invasively measure subtle changes in the structure or function of organs during disease progression or in response to experimental therapies. The ability of MRM to provide a detailed functional and anatomical picture in rats and mice, and to track this picture over time, makes it a promising platform with broad applications in biomedical research. PMID:18172332

  19. MAGNETIC RESONANCE ELECTRICAL IMPEDANCE TOMOGRAPHY (MR-EIT): A new technique for high resolution conductivity imaging

    E-print Network

    Eyüboðlu, Murat

    field measurements are performed by using magnetic resonance imaging techniques. The conductivity resonance imaging (MRI) techniques, if the conductor contains magnetic resonance active nuclei [2MAGNETIC RESONANCE ELECTRICAL IMPEDANCE TOMOGRAPHY (MR-EIT): A new technique for high resolution

  20. Predicting amyloid status in corticobasal syndrome using modified clinical criteria, magnetic resonance imaging and fluorodeoxyglucose positron emission tomography

    E-print Network

    2015-01-01

    magnetic resonance imaging; PET, positron emission tomography.magnetic resonance imaging and fluorodeoxyglucose positron emission tomographymagnetic resonance imaging (MRI) and fluorodeoxyglucose positron emission tomography (

  1. Bioengineering 208: Magnetic Resonance Imaging Laboratory Winter 2008

    E-print Network

    California at San Diego, University of

    Bioengineering 208: Magnetic Resonance Imaging Laboratory Winter 2008 Lab 2- Week of 1/14 1. Understanding the basic spin echo imaging sequence. a. Place a large phantom in a birdcage coil and position. i. From the first image, calculate what the intensity of your second image would be if the slice

  2. Bioengineering 208: Magnetic Resonance Imaging Laboratory Winter 2007

    E-print Network

    California at San Diego, University of

    Bioengineering 208: Magnetic Resonance Imaging Laboratory Winter 2007 Lab 2- Week of 1/15 1. Understanding the basic spin echo imaging sequence. a. Place a large phantom in a birdcage coil and position the first image, calculate what the intensity of your second image would be if the slice profile

  3. Magnetic resonance imaging of the central nervous system

    SciTech Connect

    Brant-Zawadzki, M.; Norman, D.

    1986-01-01

    This book provides an introduction to magnetic resonance imaging (MRI) of disorders of the central nervous system, spine, neck, and nasopharynx. The book provides guidance in performing and interpreting MRI studies for specific clinical problems. Images showing pathologic findings for various disorders and demonstrating how abnormalities detected in MRI scans can aid both in differential diagnosis and clinical staging are shown. The book summarizes the basic principles of MRI and describes equipment components and contrast agents. Explanations of common artifacts and pitfalls in image interpretation and of pathophysiologic correlates of signal alterations in magnetic resonance imaging are given. A review of the principles and potential applications of magnetic resonance spectroscopy is also included.

  4. Functional magnetic resonance imaging study of word recognition in normal elders

    E-print Network

    , functional magnetic resonance imaging; ISI, interstimulis interval; PET, positron emission tomography; SPMArticle Functional magnetic resonance imaging study of word recognition in normal elders Karen E magnetic resonance imaging; Normal aging; Serial word recognition 1. Introduction Recognition memory

  5. Update on the Magnetic Resonance Imaging core of the Alzheimer's Disease Neuroimaging Initiative

    E-print Network

    Thompson, Paul

    Update on the Magnetic Resonance Imaging core of the Alzheimer's Disease Neuroimaging Initiative of the Alzheimer's Disease Neuroimaging Initiative (ADNI) magnetic resonance imaging (MRI) core fall into three The Alzheimer's Association. All rights reserved. Keywords: Alzheimer's disease; Magnetic resonance imaging

  6. An Interactive Tool for Segmentation, Visualization, and Navigation of Magnetic Resonance Images

    E-print Network

    Bhandarkar, Suchendra "Suchi" M.

    An Interactive Tool for Segmentation, Visualization, and Navigation of Magnetic Resonance Images for the segmentation, visualization and navigation of magnetic resonance (MR) images is presented. Previous work has manner. 1. Introduction Segmentation of Magnetic Resonance (MR) images has significant ramifications

  7. DIABETIC RETINOPATHY UPDATE Magnetic resonance imaging of the retina: A brief

    E-print Network

    Duong, Timothy Q.

    DIABETIC RETINOPATHY UPDATE Magnetic resonance imaging of the retina: A brief historical and future KEYWORDS MRI; Magnetic resonance imaging; Diabetic retinopathy; Retinitis pigmentosa; Glaucoma Abstract. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 3. Magnetic resonance imaging (MRI

  8. Magnetic resonance imaging in cardiac amyloidosis

    SciTech Connect

    O'Donnell, J.K.; Go, R.T.; Bott-Silverman, C.; Feiglin, D.H.; Salcedo, E.; MacIntyre, W.J.

    1984-01-01

    Primary amyloidosis (AL) involves the myocardium in 90% of cases and may present as apparent ischemia, vascular disease, or congestive heart failure. Two-dimensional echocardiography (echo) has proven useful in the diagnosis, particularly in differentiating AL from constrictive pericarditis. The findings of thickened RV and LV myocardium, normal LV cavity dimension, and a diffuse hyperrefractile ''granular sparkling'' appearance are virtually diagnostic. Magnetic resonance (MR) imaging may improve the resolution of anatomic changes seen in cardiac AL and has the potential to provide more specific information based on biochemical tissue alterations. In this preliminary study, the authors obtained both MR and echo images in six patients with AL and biopsy-proven myocardial involvement. 5/6 patients also had Tc-99 PYP myocardial studies including emission tomography (SPECT). MR studies utilized a 0.6 Tesla superconductive magnet. End diastolic gated images were obtained with TE=30msec and TR=R-R interval on the ECG. 6/6 pts. showed LV wall thickening which was concentric and included the septum. Papillary muscles were identified in all and were enlarged in 3/6. 4/6 pts. showed RV wall thickening but to a lesser degree than LV. Pericardial effusions were present in 4 cases. These findings correlated well with the results of echo although MR gave better RV free wall resolution. PYP scans were positive in 3 pts. but there was no correlation with degree of LV thickening. The authors conclude that there are no identifiable MR findings in patients with cardiac AL which encourage further attempts to characterize myocardial involvement by measurement of MR relaxation times in vivo.

  9. Magnetic resonance imaging of oscillating electrical currents

    PubMed Central

    Halpern-Manners, Nicholas W.; Bajaj, Vikram S.; Teisseyre, Thomas Z.; Pines, Alexander

    2010-01-01

    Functional MRI has become an important tool of researchers and clinicians who seek to understand patterns of neuronal activation that accompany sensory and cognitive processes. However, the interpretation of fMRI images rests on assumptions about the relationship between neuronal firing and hemodynamic response that are not firmly grounded in rigorous theory or experimental evidence. Further, the blood-oxygen-level-dependent effect, which correlates an MRI observable to neuronal firing, evolves over a period that is 2 orders of magnitude longer than the underlying processes that are thought to cause it. Here, we instead demonstrate experiments to directly image oscillating currents by MRI. The approach rests on a resonant interaction between an applied rf field and an oscillating magnetic field in the sample and, as such, permits quantitative, frequency-selective measurements of current density without spatial or temporal cancellation. We apply this method in a current loop phantom, mapping its magnetic field and achieving a detection sensitivity near the threshold required for the detection of neuronal currents. Because the contrast mechanism is under spectroscopic control, we are able to demonstrate how ramped and phase-modulated spin-lock radiation can enhance the sensitivity and robustness of the experiment. We further demonstrate the combination of these methods with remote detection, a technique in which the encoding and detection of an MRI experiment are separated by sample flow or translation. We illustrate that remotely detected MRI permits the measurement of currents in small volumes of flowing water with high sensitivity and spatial resolution. PMID:20421504

  10. Magnetic Resonance Imaging in Postprostatectomy Radiotherapy Planning

    SciTech Connect

    Sefrova, Jana; Odrazka, Karel; Paluska, Petr; Belobradek, Zdenek; Brodak, Milos; Dolezel, Martin; Prosvic, Petr; Macingova, Zuzana; Vosmik, Milan; Hoffmann, Petr; Louda, Miroslav; Nejedla, Anna

    2012-02-01

    Purpose: To investigate whether the use of magnetic resonance imaging (MRI) in prostate bed treatment planning could influence definition of the clinical target volume (CTV) and organs at risk. Methods and Materials: A total of 21 consecutive patients referred for prostate bed radiotherapy were included in the present retrospective study. The CTV was delineated according to the European Organization for Research and Treatment of Cancer recommendations on computed tomography (CT) and T{sub 1}-weighted (T{sub 1}w) and T{sub 2}-weighted (T{sub 2}w) MRI. The CTV magnitude, agreement, and spatial differences were evaluated on the planning CT scan after registration with the MRI scans. Results: The CTV was significantly reduced on the T{sub 1}w and T{sub 2}w MRI scans (13% and 9%, respectively) compared with the CT scans. The urinary bladder was drawn smaller on the CT scans and the rectum was smaller on the MRI scans. On T{sub 1}w MRI, the rectum and urinary bladder were delineated larger than on T{sub 2}w MRI. Minimal agreement was observed between the CT and T{sub 2}w images. The main spatial differences were measured in the superior and superolateral directions in which the CTV on the MRI scans was 1.8-2.9 mm smaller. In the posterior and inferior border, no difference was seen between the CT and T{sub 1}w MRI scans. On the T{sub 2}w MRI scans, the CTV was larger in these directions (by 1.3 and 1.7 mm, respectively). Conclusions: The use of MRI in postprostatectomy radiotherapy planning resulted in a reduction of the CTV. The main differences were found in the superior part of the prostate bed. We believe T{sub 2}w MRI enables more precise definition of prostate bed CTV than conventional planning CT.

  11. Nuclear Instruments and Methods in Physics Research A 571 (2007) 7376 Magnetic resonance image reconstruction using

    E-print Network

    Robini, Marc - Pôle de Mathématiques, Institut National des Sciences Appliquées de Lyon

    2007-01-01

    Nuclear Instruments and Methods in Physics Research A 571 (2007) 73­76 Magnetic resonance image resonance imaging; k-space; Analytic image 1. Introduction Magnetic resonance imaging (MRI) plays an increas- ingly important role in medicine and biology. The raw output of a magnetic resonance (MR) imager, called

  12. Safety planning for intraoperative magnetic resonance imaging.

    PubMed

    Hemingway, Maureen; Kilfoyle, Marguerite

    2013-11-01

    An intraoperative magnetic resonance imaging (MRI) suite (ie, a type of hybrid OR) is a high-risk zone that requires well-defined safety procedures to avoid adverse events related to magnetic forces. At one facility, the opening of an MRI suite necessitated the creation of a safety plan to establish guidelines, procedures, education, and nursing care specific to the use of MRI technology in the operative environment. Formation of a steering committee enabled a multidisciplinary approach to planning and implementation. The addition of two new perioperative nursing roles (ie, MRI control room monitor, MRI safety nurse) addressed staffing challenges related to strictly enforcing MRI safety procedures and delineating duties different from those of the RN circulator. Benefits of a safe approach to an MRI-integrated operative setting included the elimination of an entire surgical experience for patients who underwent additional resection of the tumor during their initial surgical procedure instead of postoperatively or during a subsequent return to the OR. PMID:24209799

  13. Imaging intelligence with proton magnetic resonance spectroscopy

    PubMed Central

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

    2009-01-01

    Proton magnetic resonance spectroscopy (1H-MRS) is a technique for the assay of brain neurochemistry in vivo. N-acetylaspartate (NAA), the most prominent metabolite visible within the 1H-MRS spectrum, is found primarily within neurons. The current study was designed to further elucidate NAA–cognition relationships, particularly whether such relationships are moderated by sex, or tissue type (gray or white matter). We administered standard measures of intelligence to 63 young, healthy subjects and obtained spectroscopic imaging data within a slab of tissue superior to the lateral ventricles. We found that lower NAA within right anterior gray matter predicted better performance VIQ (F=6.83, p=.011, r2=.10), while higher NAA within the right posterior gray matter region predicted better PIQ (F=8.175, p=.006, r2=.12). These findings add to the small but growing body of literature linking brain biochemistry to intelligence in normal healthy subjects using 1H-MRSI. PMID:19936275

  14. Magnetic resonance imaging of the kidneys

    SciTech Connect

    Leung, A.W.L.; Bydder, G.M.; Steinter, R.E.; Bryant, D.J.; Young, I.R.

    1984-12-01

    A study of the magnetic resonance imaging (MRI) appearance of the kidneys in six normal volunteers and 52 patients is reported. Corticomedullary differentiation was seen with the inversion-recovery (IR 1400/400) sequence in the normal volunteers and in patients with functioning transplanted kidneys and acute tubular necrosis. Partial or total loss of corticomedullary differentiation was seen in glomerulonephritis, acute and chronic renal failure, renal artery stenosis, and transplant rejection. The T1 of the kidneys was increased in glomerulonephritis with neuphrotic syndrome, but the T1 was within the normal range for renal medulla in glomerulonephritis without nephrotic syndrome, renal artery stenosis, and chronic renal failure. A large staghorn calculus was demonstrated with MRI, but small calculi were not seen. Fluid within the hydonephrosis, simple renal cysts, and polycystic kidneys displayed very low signal intensity and long T1 values. Tumors displayed varied appearances. Hypernephromas were shown to be hypo- or hyperintense with the renal medulla on the IR 1400/400 sequence. After intravenous injection of gadolinium-DTPA, there was marked decrease in the tumor T1.

  15. Progesterone-Targeted Magnetic Resonance Imaging Probes

    PubMed Central

    2015-01-01

    Determination of progesterone receptor (PR) status in hormone-dependent diseases is essential in ascertaining disease prognosis and monitoring treatment response. The development of a noninvasive means of monitoring these processes would have significant impact on early detection, cost, repeated measurements, and personalized treatment options. Magnetic resonance imaging (MRI) is widely recognized as a technique that can produce longitudinal studies, and PR-targeted MR probes may address a clinical problem by providing contrast enhancement that reports on PR status without biopsy. Commercially available MR contrast agents are typically delivered via intravenous injection, whereas steroids are administered subcutaneously. Whether the route of delivery is important for tissue accumulation of steroid-modified MRI contrast agents to PR-rich tissues is not known. To address this question, modification of the chemistry linking progesterone with the gadolinium chelate led to MR probes with increased water solubility and lower cellular toxicity and enabled administration through the blood. This attribute came at a cost through lower affinity for PR and decreased ability to cross the cell membrane, and ultimately it did not improve delivery of the PR-targeted MR probe to PR-rich tissues or tumors in vivo. Overall, these studies are important, as they demonstrate that targeted contrast agents require optimization of delivery and receptor binding of the steroid and the gadolinium chelate for optimal translation in vivo. PMID:25019183

  16. Magnetic resonance imaging in isolated sagittal synostosis.

    PubMed

    Engel, Michael; Hoffmann, Juergen; Mühling, Joachim; Castrillón-Oberndorfer, Gregor; Seeberger, Robin; Freudlsperger, Christian

    2012-07-01

    Isolated fusion of the sagittal suture is the most prevalent form of craniosynostosis. Although the typical clinical appearance usually points the way to the right diagnosis, computed tomographic (CT) scans are still recommended as necessary tools for both the diagnosis of scaphocephaly and the preoperative planning. Because CT scans are accompanied by the biological effects of ionizing radiation, some authors have already postulated the use of magnetic resonance imaging (MRI) especially because MRI seems to be valuable for detecting intracranial anomalies compared with CT scans. Hence, we investigated the preoperative MRIs of 42 children with isolated sagittal synostosis to evaluate the frequency of brain anomalies and their therapeutic consequences.In our study, 10 patients (23.8%) showed pathologic MRI findings such as ventricular dilatation and hypoplastic corpus callosum, whereas 32 patients (76.2%) had an unremarkable MRI except a pathognomonic secondary deformation of the brain caused by the abnormally shaped skull, which was present in all patients. Seven patients showed clinically significant symptoms including papilledema or psychomotoric developmental delay; however, the clinical appearance was not predictive for pathologic MRI findings and vice versa.As the detection of brain anomalies had no influence on the surgical procedure or led to any additive therapy in our patients, we conclude that evaluation of possible pathologic brain findings does not legitimate the general use of MRI in clinically normal children with isolated sagittal synostosis. PMID:22801186

  17. Bioengineering 208: Magnetic Resonance Imaging Laboratory Winter 2008

    E-print Network

    California at San Diego, University of

    Bioengineering 208: Magnetic Resonance Imaging Laboratory Winter 2008 Syllabus Week Lecture Lab 1 MRI Review Hardware Overview Quadrature Detection Scanner Safety Scan phantom and reconstruct image from raw data Calculate B1 map from image data Generate quadrature ghosts 2 2D spinwarp pulse sequence

  18. Bioengineering 278: Magnetic Resonance Imaging Laboratory Winter 2014

    E-print Network

    California at San Diego, University of

    Bioengineering 278: Magnetic Resonance Imaging Laboratory Winter 2014 Lab 7 For this lab you breath holding for all data, and the automatically reconstructed dicom images. 1. Ejection Fraction that is ejected by end systole. Collect at least 5 short axis cine images with 10 or more cardiac phases. For each

  19. Bioengineering 278: Magnetic Resonance Imaging Laboratory Winter 2009

    E-print Network

    California at San Diego, University of

    Bioengineering 278: Magnetic Resonance Imaging Laboratory Winter 2009 Syllabus Week Lecture Lab 1 MRI Review Hardware Overview Quadrature Detection Scanner Safety Scan phantom and reconstruct image from raw data Calculate B1 map from image data Generate quadrature ghosts 2 2D spinwarp pulse sequence

  20. Bioengineering/Radiology 278: Magnetic Resonance Imaging Laboratory Winter 2012

    E-print Network

    California at San Diego, University of

    Bioengineering/Radiology 278: Magnetic Resonance Imaging Laboratory Winter 2012 Syllabus Week Lecture Lab 1 Nuclear Magnetization Bloch Equation Excitation The NMR Signal Scanner Safety Collect 2D image data, reconstruct image Collect and transform an FID Make a B1 map 2 Frequency Encoding Sampling

  1. Bioengineering 208: Magnetic Resonance Imaging Laboratory Winter 2007

    E-print Network

    California at San Diego, University of

    Bioengineering 208: Magnetic Resonance Imaging Laboratory Winter 2007 Lab 1 Notes 1. Calculate the excitation RF pulse waveform from a 2D gradient echo image. Everybody got the idea but there was some the image into blurred slice profile by dividing by tan(theta), then deconvolving with (thickness of tube

  2. Magnetic Field Issues in Magnetic Resonance Imaging.

    NASA Astrophysics Data System (ADS)

    Petropoulos, Labros Spiridon

    Advances in Magnetic Resonance Imaging depend on the capability of the available hardware. Specifically, for the main magnet configuration, using derivative constraints, we can create a static magnetic field with reduced levels of inhomogeneity over a prescribed imaging volume. In the gradient coil, the entire design for the axial elliptical coil, and the mathematical foundation for the transverse elliptical coil have been presented. Also, the design of a self-shielded cylindrical gradient coil with a restricted length has been presented. In order to generate gradient coils adequate for head imaging without including the human shoulders in the design, asymmetric cylindrical coils in which the gradient center is shifted axially towards the end of a finite cylinder have been introduced and theoretical as well as experimental results have been presented. In order to eliminate eddy current effects in the design of the non-shielded asymmetric gradient coils, the self-shielded asymmetric cylindrical gradient coil geometry has been introduced. Continuing the development of novel geometries for the gradient coils, the complete set of self-shielded cylindrical gradient coils, which are designed such that the x component of the magnetic field varies linearly along the three traditional gradient axes, has been presented. In order to understand the behavior of the rf field inside a dielectric object, a mathematical model is briefly presented. Although specific methods can provide an indication of the rf behavior inside a loosely dielectric object, finite element methodology is the ultimate approach for modeling the human torso and generating an accurate picture for the shape of the rf field inside this dielectric object. For this purpose we have developed a 3D finite element model, using the Coulomb gauge condition as a constraint. Agreement with the heterogeneous multilayer planar model has been established, while agreement with theoretical results from the spherical model and experimental results from the cylindrical model at 170 M H z is very good and provides an encouraging sign for using this finite element approach for modeling the rf inside the human body. (Abstract shortened by UMI.).

  3. Rectal Cancer Magnetic Resonance Imaging: Imaging Beyond Morphology.

    PubMed

    Prezzi, D; Goh, V

    2016-02-01

    Magnetic resonance imaging (MRI) has in recent years progressively established itself as one of the most valuable modalities for the diagnosis, staging and response assessment of rectal cancer and its use has largely focused on accurate morphological assessment. The potential of MRI, however, extends beyond detailed anatomical depiction: aspects of tissue physiology, such as perfusion, oxygenation and water molecule diffusivity, can be assessed indirectly. Functional MRI is rapidly evolving as a promising non-invasive assessment tool for tumour phenotyping and assessment of response to new therapeutic agents. In spite of promising experimental data, the evidence base for the application of functional MRI techniques in rectal cancer remains modest, reflecting the relatively poor agreement on technical protocols, image processing techniques and quantitative methodology to date, hampering routine integration into clinical management. This overview outlines the established strengths and the critical limitations of anatomical MRI in rectal cancer; it then introduces some of the functional MRI techniques and quantitative analysis methods that are currently available, describing their applicability in rectal cancer and reviewing the relevant literature; finally, it introduces the concept of a multi-parametric quantitative approach to rectal cancer. PMID:26586163

  4. FY08 Annual Report for Nuclear Resonance Fluorescence Imaging

    SciTech Connect

    Warren, Glen A.; Caggiano, Joseph A.

    2009-01-06

    FY08 annual report for project the "Nuclear Resonance Fluorescence Imaging" project. Reviews accomplishments of last 3 years, including U-235 signature search, comparison of different photon sources, and examination of NRF measurements using monochromatic photon source.

  5. Fast neutron resonance radiography for element imaging : theory and applications

    E-print Network

    Chen, Gongyin, 1968-

    2001-01-01

    Fast Neutron Resonance Radiography (NRR) has been devised as an elemental imaging method, with immediate applications to detecting explosives and drugs in passenger suitcases. In the NRR method, the 2-D elemental mapping ...

  6. Magnetic resonance imaging contrast agents for chemical sensing

    E-print Network

    Liu, Vincent Hok

    2014-01-01

    Magnetic resonance imaging (MRI) is frequently used for examining the human body. MRI contrast agents currently used in the clinic assist physicians in locating problematic areas, but other tools are needed to interrogate ...

  7. RF Pulse Design for Parallel Excitation in Magnetic Resonance Imaging 

    E-print Network

    Liu, Yinan

    2012-07-16

    Parallel excitation is an emerging technique to improve or accelerate multi-dimensional spatially selective excitations in magnetic resonance imaging (MRI) using multi-channel transmit arrays. The technique has potential in many applications...

  8. Microfluidically Cryo-Cooled Planar Coils for Magnetic Resonance Imaging 

    E-print Network

    Koo, Chiwan

    2013-08-09

    High signal-to-noise ratio (SNR) is typically required for higher resolution and faster speed in magnetic resonance imaging (MRI). Planar microcoils as receiver probes in MRI systems offer the potential to be configured into array elements for fast...

  9. Magnetic Resonance Imaging Method For Estimating Cone Of Uncertainty

    Cancer.gov

    The National Institute of Child Health and Human Development (NICHD), Section on Tissue Biophysics and Biomimetics, is seeking statements of capability or interest from parties interested in collaborative research to further develop, evaluate, or commercialize magnetic resonance imaging techniques.

  10. Improvements in magnetic resonance imaging excitation pulse design

    E-print Network

    Zelinski, Adam Charles

    2008-01-01

    This thesis focuses on the design of magnetic resonance imaging (MRI) radio-frequency (RF) excitation pulses, and its primary contributions are made through connections with the novel multiple-system single-output (MSSO) ...

  11. The Nobel Prize in Medicine for Magnetic Resonance Imaging

    ERIC Educational Resources Information Center

    Fry, Charles G.

    2004-01-01

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

  12. Cranial and spinal magnetic resonance imaging: A guide and atlas

    SciTech Connect

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

    1987-01-01

    This atlas provides a clinical guide to interpreting cranial and spinal magnetic resonance images. The book includes coverage of the cerebrum, temporal bone, and cervical, thoracic, and lumbar spine, with more than 400 scan images depicting both normal anatomy and pathologic findings. Introductory chapters review the practical physics of magnetic resonance (MR) imaging, offer guidelines for interpreting cranial MR scans, and provide coverage of each anatomic region of the cranium and spine. For each region, scans accompanied by captions, show normal anatomic sections matched with MR images. These are followed by MR scans depicting various disease states.

  13. Improved Time Series Reconstruction for Dynamic Magnetic Resonance Imaging

    PubMed Central

    Sümbül, Uygar; Santos, Juan M.; Pauly, John M.

    Time series of in-vivo magnetic resonance images exhibit high levels of temporal correlation. Higher temporal resolution reconstructions are obtained by acquiring data at a fraction of the Nyquist rate and resolving the resulting aliasing using the correlation information. The dynamic imaging experiment is modeled as a linear dynamical system. A Kalman filter based unaliasing reconstruction is described for accelerated dynamic magnetic resonance imaging (MRI). The algorithm handles arbitrary readout trajectories naturally. The reconstruction is causal and very fast, making it applicable to real-time imaging. In-vivo results are presented for cardiac MRI of healthy volunteers. PMID:19150785

  14. Parallel magnetic resonance imaging: characterization and comparison 

    E-print Network

    Rane, Swati Dnyandeo

    2005-11-01

    of the optimal method for parallel imaging depending on a particular imaging environment and scanning parameters. Simulations on real MR phased-array data show that SENSE and GRAPPA provide better image reconstructions when compared to the remaining techniques....

  15. Fundamental and practical limits to image acceleration in parallel magnetic resonance imaging

    E-print Network

    Ohliger, Michael A

    2005-01-01

    Imaging speed in conventional magnetic resonance imaging (MRI) is limited by the performance of magnetic field gradients and the rate of power deposition in tissue. Parallel MRI techniques overcome these constraints by ...

  16. Advanced image reconstruction in parallel magnetic resonance imaging : constraints and solutions.

    E-print Network

    Yeh, Ernest Nanjung, 1975-

    2005-01-01

    Imaging speed is a crucial consideration for magnetic resonance imaging (MRI). The speed of conventional MRI is limited by hardware performance and physiological safety measures. "Parallel" MRI is a new technique that ...

  17. Imaging of the hip joint. Computed tomography versus magnetic resonance imaging

    NASA Technical Reports Server (NTRS)

    Lang, P.; Genant, H. K.; Jergesen, H. E.; Murray, W. R.

    1992-01-01

    The authors reviewed the applications and limitations of computed tomography (CT) and magnetic resonance (MR) imaging in the assessment of the most common hip disorders. Magnetic resonance imaging is the most sensitive technique in detecting osteonecrosis of the femoral head. Magnetic resonance reflects the histologic changes associated with osteonecrosis very well, which may ultimately help to improve staging. Computed tomography can more accurately identify subchondral fractures than MR imaging and thus remains important for staging. In congenital dysplasia of the hip, the position of the nonossified femoral head in children less than six months of age can only be inferred by indirect signs on CT. Magnetic resonance imaging demonstrates the cartilaginous femoral head directly without ionizing radiation. Computed tomography remains the imaging modality of choice for evaluating fractures of the hip joint. In some patients, MR imaging demonstrates the fracture even when it is not apparent on radiography. In neoplasm, CT provides better assessment of calcification, ossification, and periosteal reaction than MR imaging. Magnetic resonance imaging, however, represents the most accurate imaging modality for evaluating intramedullary and soft-tissue extent of the tumor and identifying involvement of neurovascular bundles. Magnetic resonance imaging can also be used to monitor response to chemotherapy. In osteoarthrosis and rheumatoid arthritis of the hip, both CT and MR provide more detailed assessment of the severity of disease than conventional radiography because of their tomographic nature. Magnetic resonance imaging is unique in evaluating cartilage degeneration and loss, and in demonstrating soft-tissue alterations such as inflammatory synovial proliferation.

  18. Silicon Nanoparticles as Hyperpolarized Magnetic Resonance Imaging Agents

    PubMed Central

    Aptekar, Jacob W.; Cassidy, Maja C.; Johnson, Alexander C.; Barton, Robert A.; Lee, Menyoung; Ogier, Alexander C.; Vo, Chinh; Anahtar, Melis N.; Ren, Yin; Bhatia, Sangeeta N.; Ramanathan, Chandrasekhar; Cory, David G.; Hill, Alison L.; Mair, Ross W.; Rosen, Matthew S.; Walsworth, Ronald L.

    2014-01-01

    Magnetic resonance imaging of hyperpolarized nuclei provides high image contrast with little or no background signal. To date, in-vivo applications of pre-hyperpolarized materials have been limited by relatively short nuclear spin relaxation times. Here, we investigate silicon nanoparticles as a new type of hyperpolarized magnetic resonance imaging agent. Nuclear spin relaxation times for a variety of Si nanoparticles are found to be remarkably long, ranging from many minutes to hours at room temperature, allowing hyperpolarized nanoparticles to be transported, administered, and imaged on practical time scales. Additionally, we demonstrate that Si nanoparticles can be surface functionalized using techniques common to other biologically targeted nanoparticle systems. These results suggest that Si nanoparticles can be used as a targetable, hyperpolarized magnetic resonance imaging agent with a large range of potential applications. PMID:19950973

  19. Magnetic-resonance pore imaging of nonsymmetric microscopic pore shapes

    NASA Astrophysics Data System (ADS)

    Hertel, Stefan Andreas; Wang, Xindi; Hosking, Peter; Simpson, M. Cather; Hunter, Mark; Galvosas, Petrik

    2015-07-01

    Imaging of the microstructure of porous media such as biological tissue or porous solids is of high interest in health science and technology, engineering and material science. Magnetic resonance pore imaging (MRPI) is a recent technique based on nuclear magnetic resonance (NMR) which allows us to acquire images of the average pore shape in a given sample. Here we provide details on the experimental design, challenges, and requirements of MRPI, including its calibration procedures. Utilizing a laser-machined phantom sample, we present images of microscopic pores with a hemiequilateral triangular shape even in the presence of NMR relaxation effects at the pore walls. We therefore show that MRPI is applicable to porous samples without a priori knowledge about their pore shape and symmetry. Furthermore, we introduce "MRPI mapping," which combines MRPI with conventional magnetic resonance imaging (MRI). This enables one to resolve microscopic pore sizes and shapes spatially, thus expanding the application of MRPI to samples with heterogeneous distributions of pores.

  20. Inhomogeneity correction for magnetic resonance images with fuzzy C-mean algorithm

    E-print Network

    Inhomogeneity correction for magnetic resonance images with fuzzy C-mean algorithm Xiang Li of New York at Stony Brook, USA Abstract: Segmentation of magnetic resonance (MR) images plays field, Magnetic Resonance Imaging. I. Introduction Magnetic Resonance Imaging (MRI) has several

  1. Mapping motion from 4D-MRI to 3D-CT for use in 4D dose calculations: A technical feasibility study

    SciTech Connect

    Boye, Dirk; Lomax, Tony; Knopf, Antje

    2013-06-15

    Purpose: Target sites affected by organ motion require a time resolved (4D) dose calculation. Typical 4D dose calculations use 4D-CT as a basis. Unfortunately, 4D-CT images have the disadvantage of being a 'snap-shot' of the motion during acquisition and of assuming regularity of breathing. In addition, 4D-CT acquisitions involve a substantial additional dose burden to the patient making many, repeated 4D-CT acquisitions undesirable. Here the authors test the feasibility of an alternative approach to generate patient specific 4D-CT data sets. Methods: In this approach motion information is extracted from 4D-MRI. Simulated 4D-CT data sets [which the authors call 4D-CT(MRI)] are created by warping extracted deformation fields to a static 3D-CT data set. The employment of 4D-MRI sequences for this has the advantage that no assumptions on breathing regularity are made, irregularities in breathing can be studied and, if necessary, many repeat imaging studies (and consequently simulated 4D-CT data sets) can be performed on patients and/or volunteers. The accuracy of 4D-CT(MRI)s has been validated by 4D proton dose calculations. Our 4D dose algorithm takes into account displacements as well as deformations on the originating 4D-CT/4D-CT(MRI) by calculating the dose of each pencil beam based on an individual time stamp of when that pencil beam is applied. According to corresponding displacement and density-variation-maps the position and the water equivalent range of the dose grid points is adjusted at each time instance. Results: 4D dose distributions, using 4D-CT(MRI) data sets as input were compared to results based on a reference conventional 4D-CT data set capturing similar motion characteristics. Almost identical 4D dose distributions could be achieved, even though scanned proton beams are very sensitive to small differences in the patient geometry. In addition, 4D dose calculations have been performed on the same patient, but using 4D-CT(MRI) data sets based on variable breathing patterns to show the effect of possible irregular breathing on active scanned proton therapy. Using a 4D-CT(MRI), including motion irregularities, resulted in significantly different proton dose distributions. Conclusions: The authors have demonstrated that motion information from 4D-MRI can be used to generate realistic 4D-CT data sets on the basis of a single static 3D-CT data set. 4D-CT(MRI) presents a novel approach to test the robustness of treatment plans in the circumstance of patient motion.

  2. TH-A-BRF-12: Assessment of 4D-MRI for Robust Motion and Volume Characterization

    SciTech Connect

    Glide-Hurst, C; Kim, J; Wen, N; Chetty, I; Hu, Y; Mutic, S

    2014-06-15

    Purpose: Precise radiation therapy for abdominal lesions is complicated by respiratory motion and poor soft tissue contrast from 4DCT whereas 4DMRI provides superior tissue discrimination. We evaluated a novel 4D-MRI algorithm for MR-SIM motion management. Methods: Respiratory-triggered, T2-weighted single-shot Turbo Spin Echo 4D-MRI was evaluated for open high-field 1.0T MR-SIM. A programmable platform pulled objects on a trolley ?2 cm superior-inferior (S-I) for “regular” (sinusoidal, (1-cos{sup 2}), 3-5 second periods) and “irregular” breathing patterns (exaggerated (1-cos{sup 2}) and patient curves), while a respiratory waveform was generated via a pressure sensor device. Coronal 4D-MRIs (2–12;10 phases, TE/TR/? = 35?61/6100 ms/90°, voxel=1×1×4 mm{sup 3}) were acquired for 54 unique phantom cases. Abdominal 4D?MRIs were evaluated for 5 healthy volunteers and 1 liver cancer patient (6–10 phases, TE/TR/? = 30?96/4500?6100 ms/90°, voxel=1×1×5–10 mm{sup 3}) on an IRB-approved protocol. Duty cycle, scan time, and excursion were evaluated between phase acquisitions and compared to coronal cine-MRI (?1 frame/sec). Maximum intensity projections (MIPs) were analyzed. Results: In phantom, average duty cycle was 42.6 ± 11.4% (range: 23.6–69.1%). Regular, periodic breathing (sinusoidal, (1-cos{sup 2})) yielded higher duty cycles than irregular (48.5% and 35.9%, respectively, p<0.001) and fast periods had higher duty cycles than slow (50.4% for 3s and 39.4% for 5s, p<0.001). ?4-fold acquisition time increase was measured for 10-phase versus 2-phase. MIP renderings revealed that SI object extent was underestimated a maximum of 4% (3mm) and 8% (6mm) for cine and 2-phase 4D-MRI, respectively, with respect to 10-phases. However, this was waveform dependent. A highly irregular breathing volunteer yielded lowest duty cycle (23%) and longest 10-phase scan time (?14 minutes), although 6-phase acquisition for a liver cancer patient was reasonable (50% and 7.4 minutes, respectively). Conclusion: 4D-MRI offers potential for excursion characterization, although results suggest the use of adequate phases is important. Further application and clinical validation are warranted. Research supported in part by a grant from Philips HealthCare (Best, Netherlands) and an Internal Mentored Grant from Henry Ford Health System.

  3. Magnetic Resonance Perfusion Imaging in the Study of Language

    ERIC Educational Resources Information Center

    Hillis, Argye E.

    2007-01-01

    This paper provides a brief review of various uses of magnetic resonance perfusion imaging in the investigation of brain/language relationships. The reviewed studies illustrate how perfusion imaging can reveal areas of brain where dysfunction due to low blood flow is associated with specific language deficits, and where restoration of blood flow…

  4. Magnetic resonance imaging of the bowel: today and tomorrow.

    PubMed

    Kinner, S; Hahnemann, M L; Forsting, M; Lauenstein, T C

    2015-03-01

    Magnetic resonance imaging of the small bowel has been feasible for more than 15 years. This review is meant to give an overview of typical techniques, sequences and indications. Furthermore, newly evaluated promising techniques are presented, which have an impact on the advance of MR imaging of the small and large bowel. PMID:25703124

  5. Intravascular Magnetic Resonance Imaging Using a Loopless Catheter Antenna

    E-print Network

    Atalar, Ergin

    Intravascular Magnetic Resonance Imaging Using a Loopless Catheter Antenna Ogan Ocali, Ergin Atalar is very critical in imaging small vessels such as coronary arteries. Catheter coils have a loop.The use of a loopless intravascularcatheter antenna is proposed to overcomethese problems. The catheter

  6. Enzymatically Amplified Surface Plasmon Resonance Imaging Detection of DNA by

    E-print Network

    Enzymatically Amplified Surface Plasmon Resonance Imaging Detection of DNA by Exonuclease III utilizing the enzyme exonuclease III in conjunction with 3-terminated DNA microarrays for the amplifiedIII with double-stranded DNA as well as this new enzymatically amplified SPR imaging process with a 16-mer target

  7. NMR-0Fessler, Univ. of Michigan Nuclear Magnetic Resonance Imaging

    E-print Network

    Fessler, Jeffrey A.

    NMR-0Fessler, Univ. of Michigan Nuclear Magnetic Resonance Imaging Jeffrey A. Fessler EECS Department The University of Michigan NSS-MIC: Fundamentals of Medical Imaging Oct. 20, 2003 #12;NMR-1Fessler, Univ. of Michigan Outline · Background · Basic physics · 4 magnetic fields · Bloch equation

  8. Physiological Noise in Oxygenation-Sensitive Magnetic Resonance Imaging

    E-print Network

    Glover, Gary H.

    Physiological Noise in Oxygenation-Sensitive Magnetic Resonance Imaging Gunnar Kru¨ger* and Gary H image noise: T 2 S 2 0 2 P 2 . [1] Here, T is the thermal noise from the subject and scanner electronics. Glover The physiological noise in the resting brain, which arises from fluctuations in metabolic

  9. Artifacts and pitfalls in shoulder magnetic resonance imaging*

    PubMed Central

    Marcon, Gustavo Felix; Macedo, Tulio Augusto Alves

    2015-01-01

    Magnetic resonance imaging has revolutionized the diagnosis of shoulder lesions, in many cases becoming the method of choice. However, anatomical variations, artifacts and the particularity of the method may be a source of pitfalls, especially for less experienced radiologists. In order to avoid false-positive and false-negative results, the authors carried out a compilation of imaging findings that may simulate injury. It is the authors’ intention to provide a useful, consistent and comprehensive reference for both beginner residents and skilled radiologists who work with musculoskeletal magnetic resonance imaging, allowing for them to develop more precise reports and helping them to avoid making mistakes. PMID:26379323

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

    NASA Technical Reports Server (NTRS)

    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.

  11. Reconstruction of pulse noisy images via stochastic resonance

    PubMed Central

    Han, Jing; Liu, Hongjun; Sun, Qibing; Huang, Nan

    2015-01-01

    We investigate a practical technology for reconstructing nanosecond pulse noisy images via stochastic resonance, which is based on the modulation instability. A theoretical model of this method for optical pulse signal is built to effectively recover the pulse image. The nanosecond noise-hidden images grow at the expense of noise during the stochastic resonance process in a photorefractive medium. The properties of output images are mainly determined by the input signal-to-noise intensity ratio, the applied voltage across the medium, and the correlation length of noise background. A high cross-correlation gain is obtained by optimizing these parameters. This provides a potential method for detecting low-level or hidden pulse images in various imaging applications. PMID:26067911

  12. Functional imaging of the central nervous system using magnetic resonance imaging and positron emission tomography.

    PubMed

    Neil, J J

    1993-12-01

    There have been striking advances recently in magnetic resonance imaging and positron emission tomography (PET) imaging of the central nervous system, particularly in the area of "functional" imaging. We discuss these advances with emphasis on the similarities and differences between the PET and magnetic resonance imaging methods. In addition, we examine recent progress and controversies in the use of volume-localized nuclear magnetic resonance spectroscopy. Finally, we review the use of three-dimensional acquisition for PET studies, with an evaluation of the relative advantages and disadvantages of this modification of the PET technique. PMID:8293168

  13. Bridging the Gap: Integrating Cellular and Functional Magnetic Resonance Imaging Studies

    E-print Network

    Rotstein, Horacio G.

    Bridging the Gap: Integrating Cellular and Functional Magnetic Resonance Imaging Studies and interpreting experimental results. The temporal and spatial resolution of functional magnetic resonance imaging imaging studies of the medial temporal lobe. In addition, we describe recent computational models

  14. Multi-contrast magnetic resonance image reconstruction

    NASA Astrophysics Data System (ADS)

    Liu, Meng; Chen, Yunmei; Zhang, Hao; Huang, Feng

    2015-03-01

    In clinical exams, multi-contrast images from conventional MRI are scanned with the same field of view (FOV) for complementary diagnostic information, such as proton density- (PD-), T1- and T2-weighted images. Their sharable information can be utilized for more robust and accurate image reconstruction. In this work, we propose a novel model and an efficient algorithm for joint image reconstruction and coil sensitivity estimation in multi-contrast partially parallel imaging (PPI) in MRI. Our algorithm restores the multi-contrast images by minimizing an energy function consisting of an L2-norm fidelity term to reduce construction errors caused by motion, a regularization term of underlying images to preserve common anatomical features by using vectorial total variation (VTV) regularizer, and updating sensitivity maps by Tikhonov smoothness based on their physical property. We present the numerical results including T1- and T2-weighted MR images recovered from partially scanned k-space data and provide the comparisons between our results and those obtained from the related existing works. Our numerical results indicate that the proposed method using vectorial TV and penalties on sensitivities can be made promising and widely used for multi-contrast multi-channel MR image reconstruction.

  15. Surface Plasmon Resonance Assisted Optical Imaging

    E-print Network

    Poon, Andrew Wing On

    Monochromator White LED light source (broad band) Experimental Setup Key part Prism White LED light source (wide) Surface plasmon wave Order of nano-meter Prism Objective Principle What is Surface Plasmon Resonance (SPR-polarized incident light into surface plasmons. It is sensitive to the refractive index of the medium on the opposite

  16. Imaging Intelligence with Proton Magnetic Resonance Spectroscopy

    ERIC Educational Resources Information Center

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

    2009-01-01

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

  17. Basic Principles of Magnetic Resonance Imaging—An Update

    PubMed Central

    Scherzinger, Ann L.; Hendee, William R.

    1985-01-01

    Magnetic resonance (MR) imaging technology has undergone many technologic advances over the past few years. Many of these advances were stimulated by the wealth of information emerging from nuclear magnetic resonance research in the areas of new and optimal scanning methods and radio-frequency coil design. Other changes arose from the desire to improve image quality, ease siting restrictions and generally facilitate the clinical use of MR equipment. Many questions, however, remain unanswered. Perhaps the most controversial technologic question involves the optimal field strength required for imaging or spectroscopic applications or both. Other issues include safety and clinical efficacy. Technologic issues affect all aspects of MR use including the choice of equipment, examination procedure and image interpretation. Thus, an understanding of recent changes and their theoretic basis is necessary. ImagesFigure 9. PMID:3911591

  18. Resonant acoustic nonlinearity for defect-selective imaging and NDT

    NASA Astrophysics Data System (ADS)

    Solodov, Igor

    2015-10-01

    The bottleneck problem of nonlinear NDT is a low efficiency of conversion from fundamental frequency to nonlinear frequency components. In this paper, it is proposed to use a combination of mechanical resonance and nonlinearity of defects to enhance the input-output conversion. The concept of the defect as a nonlinear oscillator brings about new dynamic and frequency scenarios characteristic of parametric oscillations. The modes observed in experiment include sub- and superharmonic resonances with anomalously efficient generation of the higher harmonics and subharmonics. A modified version of the superharmonic resonance (combination frequency resonance) is used to enhance the efficiency of frequency mixing mode of nonlinear NDT. All the resonant nonlinear modes are strongly localized in the defect area that provides a background for high-contrast highly-sensitive defect- and frequency-selective imaging.

  19. Method for nuclear magnetic resonance imaging

    DOEpatents

    Kehayias, J.J.; Joel, D.D.; Adams, W.H.; Stein, H.L.

    1988-05-26

    A method for in vivo NMR imaging of the blood vessels and organs of a patient characterized by using a dark dye-like imaging substance consisting essentially of a stable, high-purity concentration of D/sub 2/O in a solution with water.

  20. Magnetic resonance imaging of the central nervous system

    SciTech Connect

    Brant-Zawadzki, M.; Norman, D.

    1987-01-01

    This text provides an introduction to magnetic resonance imaging (MRI) of disorders of the central nervous system, spine, neck, and nasopharynx. The book offers guidance in performing and interpreting MRI studies for specific clinical problems. Included are more than 800 images showing pathologic findings for various disorders and demonstrating how abnormalities detected in MRI scans can aid both in differential diagnosis and in clinical staging. The book summarizes the basic principles of MRI and describes the major equipment components and contrast agents. A review of the principles and potential applications of magnetic resonance spectroscopy is also included.

  1. Accelerated nanoscale magnetic resonance imaging through phase multiplexing

    SciTech Connect

    Moores, B. A.; Eichler, A. Takahashi, H.; Navaretti, P.; Degen, C. L.; Tao, Y.

    2015-05-25

    We report a method for accelerated nanoscale nuclear magnetic resonance imaging by detecting several signals in parallel. Our technique relies on phase multiplexing, where the signals from different nuclear spin ensembles are encoded in the phase of an ultrasensitive magnetic detector. We demonstrate this technique by simultaneously acquiring statistically polarized spin signals from two different nuclear species ({sup 1}H, {sup 19}F) and from up to six spatial locations in a nanowire test sample using a magnetic resonance force microscope. We obtain one-dimensional imaging resolution better than 5?nm, and subnanometer positional accuracy.

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

    PubMed Central

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

    2015-01-01

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

  3. Nuclear magnetic resonance imaging at microscopic resolution

    NASA Astrophysics Data System (ADS)

    Johnson, G. Allan; Thompson, Morrow B.; Gewalt, Sally L.; Hayes, Cecil E.

    Resolution limits in NMR imaging are imposed by bandwidth considerations, available magnetic gradients for spatial encoding, and signal to noise. This work reports modification of a clinical NMR imaging device with picture elements of 500 × 500 × 5000 ?m to yield picture elements of 50 × 50 × 1000 ?m. Resolution has been increased by using smaller gradient coils permitting gradient fields >0.4 mT/cm. Significant improvements in signal to noise are achieved with smaller rf coils, close attention to choice of bandwidth, and signal averaging. These improvements permit visualization of anatomical structures in the rat brain with an effective diameter of 1 cm with the same definition as is seen in human imaging. The techniques and instrumentation should open a number of basic sciences such as embryology, plant sciences, and teratology to the potentials of NMR imaging.

  4. Portable low-cost magnetic resonance imaging

    E-print Network

    Cooley, Clarissa Zimmerman

    2014-01-01

    Purpose: As the premiere modality for brain imaging, MRI could find wider applicability if lightweight, portable systems were available for siting in unconventional locations such as intensive care units (ICUs), physician ...

  5. High resolution resonance ionization imaging detector and method

    DOEpatents

    Winefordner, James D. (Gainesville, FL); Matveev, Oleg I. (Gainesville, FL); Smith, Benjamin W. (Gainesville, FL)

    1999-01-01

    A resonance ionization imaging device (RIID) and method for imaging objects using the RIID are provided, the RIID system including a RIID cell containing an ionizable vapor including monoisotopic atoms or molecules, the cell being positioned to intercept scattered radiation of a resonance wavelength .lambda..sub.1 from the object which is to be detected or imaged, a laser source disposed to illuminate the RIID cell with laser radiation having a wavelength .lambda..sub.2 or wavelengths .lambda..sub.2, .lambda..sub.3 selected to ionize atoms in the cell that are in an excited state by virtue of having absorbed the scattered resonance laser radiation, and a luminescent screen at the back surface of the RIID cell which presents an image of the number and position of charged particles present in the RIID cell as a result of the ionization of the excited state atoms. The method of the invention further includes the step of initially illuminating the object to be detected or imaged with a laser having a wavelength selected such that the object will scatter laser radiation having the resonance wavelength .lambda..sub.1.

  6. He Lung Imaging in an Open Access, Very-Low-Field Human Magnetic Resonance Imaging System

    E-print Network

    Walsworth, Ronald L.

    3 He Lung Imaging in an Open Access, Very-Low-Field Human Magnetic Resonance Imaging System R. W. Butler,6 F. W. Hersman,4 and R. L. Walsworth1 The human lung and its functions are extremely sensitive lung restrict sub- jects to lying horizontally. Imaging of human lungs using inhaled laser-polarized 3

  7. Partial volume segmentation of brain magnetic resonance images based on maximum a posteriori probability

    E-print Network

    Partial volume segmentation of brain magnetic resonance images based on maximum a posteriori, and image-intensity inhomogeneity render a challenging task for segmentation of brain magnetic resonance MR correction I. INTRODUCTION Magnetic resonance MR imaging has several advantages over other medical imaging

  8. Radiologic Sciences BS, Magnetic Resonance Imaging Emphasis, 2015-2016 Name ID# Date

    E-print Network

    Barrash, Warren

    Radiologic Sciences BS, Magnetic Resonance Imaging Emphasis, 2015-2016 Name ID# Date Course Number and Contrast Medias 1 RADSCI 430 Comparative Sectional Imaging 3 RADSCI 440 Principles of Magnetic Resonance Imaging I 3 RADSCI 440L Principles of Magnetic Resonance Imaging I Lab 1 RADSCI 441 Procedural Case

  9. Fast Magnetic Resonance Imaging via Adaptive Broadband Encoding of the MR Signal Content

    E-print Network

    Edelman, Alan

    1 Fast Magnetic Resonance Imaging via Adaptive Broadband Encoding of the MR Signal Content Dimitris-efficiency of contin- uous data acquisition in Magnetic Resonance Imaging. In order to realize this increase- imum data MR image reconstruction, Broadband MRI. I. INTRODUCTION Magnetic Resonance Imaging (MRI

  10. Cardiac Magnetic Resonance Imaging by Retrospective Gating: Mathematical Modelling and Reconstruction Algorithms

    E-print Network

    Roerdink, Jos B.T.M.

    Cardiac Magnetic Resonance Imaging by Retrospective Gating: Mathematical Modelling of magnetic resonance imaging (MRI) of the beating human heart. In particular we investigate the so, 69K45, 78A70, 92A09. Keywords: magnetic resonance imaging, cardiac imaging, retrospective gating

  11. MIXTURE OF COMPETITIVE LINEAR MODELS FOR PHASED-ARRAY MAGNETIC RESONANCE IMAGING

    E-print Network

    Slatton, Clint

    MIXTURE OF COMPETITIVE LINEAR MODELS FOR PHASED-ARRAY MAGNETIC RESONANCE IMAGING£ Deniz Erdogmus-array magnetic resonance imaging is an important contem- porary research field in terms of the expected clinical. INTRODUCTION Magnetic resonance image (MRI) image reconstruction with phased-array coils is being widely

  12. Automatic landmarking of magnetic resonance brain images

    NASA Astrophysics Data System (ADS)

    Izard, Camille; Jedynak, Bruno M.; Stark, Craig E. L.

    2005-04-01

    Landmarking MR images is crucial in registering brain structures from different images. It consists in locating the voxel in the image that corresponds to a well-defined point in the anatomy, called the landmark. Example of landmarks are the apex of the head (HoH) of Hippocampus, the tail and the tip of the splenium of the corpus collosum (SCC). Hand landmarking is tedious and time-consuming. It requires an adequate training. Experimental studies show that the results are dependent on the landmarker and drifting with time. We propose a generic algorithm performing automated detection of landmarks. The first part consists in learning from a training set of landmarked images the parameters of a probabilistic model, using the EM algorithm. The second part inputs the estimated parameters and a new image, and outputs a voxel as a predicted location for the landmark. The algorithm is demonstrated on the HoH and the SCC. In contrast with competing approaches, the algorithm is generic: it can be used to detect any landmark, given a hand-labeled training set of images.

  13. Magnetic resonance imaging of the cirrhotic liver: An update

    PubMed Central

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

    2015-01-01

    Noninvasive imaging has become the standard for hepatocellular carcinoma (HCC) diagnosis in cirrhotic livers. In this review paper, we go over the basics of MR imaging in cirrhotic livers and describe the imaging appearance of a spectrum of hepatic nodules marking the progression from regenerative nodules to low- and high-grade dysplastic nodules, and ultimately to HCCs. We detail and illustrate the typical imaging appearances of different types of HCC including focal, multi-focal, massive, diffuse/infiltrative, and intra-hepatic metastases; with emphasis on the diagnostic value of MR in imaging these lesions. We also shed some light on liver imaging reporting and data system, and the role of different magnetic resonance imaging (MRI) contrast agents and future MRI techniques including the use of advanced MR pulse sequences and utilization of hepatocyte-specific MRI contrast agents, and how they might contribute to improving the diagnostic performance of MRI in early stage HCC diagnosis. PMID:25848471

  14. Three-dimensional magnetic resonance cardiac imaging shows initial promise

    SciTech Connect

    Not Available

    1988-04-15

    Three-dimensional magnetic resonance imaging (3-D MRI) of the heart is already receiving encouraging reviews from heart surgeons, says Michael Vannier, MD, an associate professor of radiology at Washington University School of Medicine, St. Louis. In fact, the demand for his group's 3-D images is becoming overwhelming, Vannier says. So far, the group has used 3-D MRI to evaluate congenital heart disease. The advantage of the 3-D system is that, even to an untrained eye, anomalies are apparent and the images can even be animated. Many of the patients are infants, who are sedated while the images are acquired. When the information is combined, the averaged image produced represents a slice about 5 mm thick. The computer then stacks a number of those images together to make the 3-D image. Total scanning takes about one hour.

  15. Surface plasmon resonance imaging by holographic enhanced mapping.

    PubMed

    Mandracchia, B; Pagliarulo, V; Paturzo, M; Ferraro, P

    2015-04-21

    We designed, constructed and tested a holographic surface plasmon resonance (HoloSPR) objective-based microscope for simultaneous amplitude-contrast and phase-contrast surface plasmon resonance imaging (SPRi). SPRi is a widely spread tool for label-free detection of changes in refractive index and concentration, as well as mapping of thin films. Currently, most of the SPR sensors rely on the detection of amplitude or phase changes of light. Despite the high sensitivities achieved so far, each technique alone has a limited detection range with optimal sensitivity. Here we use a high numerical aperture objective that avoids all the limitations due to the use of a prism-based configuration, yielding highly magnified and distortion-free images. Holographic reconstructions of SPR images and real-time kinetic measurements are presented to show the capability of HoloSPR to provide a versatile imaging method for high-throughput SPR detection complementary to conventional SPR techniques. PMID:25816225

  16. Use of nuclear magnetic resonance imaging to study asphalt

    SciTech Connect

    Miknis, F.P.; Netzel, D.A.

    1996-12-31

    Magnetic resonance imaging (MRI) combines the basic principles of magnetic resonance with spatial encoding to obtain images of the distribution of fluids in samples. Because of the sensitivity of the hydrogen nucleus in NMR and because of its favorable relaxation times, water is the fluid most often imaged. This favorable aspect suggests that MRI might be used to obtain valuable information about water susceptibility and moisture damage mechanisms in asphalt. However, it has only been fairly recently that nonmedical applications of MRI have been increasing partly because of improvements in instrumentation and speed of data acquisition. MRI has been used to measure the distribution of fluids in porous rocks, ceramics, wood, other plant materials, synthetic polymers, solvent diffusion in polymers, coals, and bonding of adhesives. MRI measurements were made using spin echo or three dimensional imaging techniques.

  17. Magnetic Resonance Imaging in Epidemic Adenoviral Keratoconjunctivitis

    PubMed Central

    Horton, Jonathan C.; Miller, Steven

    2015-01-01

    Most clinicians would agree that there is no reason to obtain a magnetic resonance (MR) scan to evaluate a patient with viral conjunctivitis. We scheduled a patient for an annual MR scan to monitor his optic nerve meningiomas. By coincidence, he had florid viral conjunctivitis the day the scan was performed. It showed severe eyelid edema, contrast enhancement of the anterior orbit, enlargement of the lacrimal gland, and obstruction of the nasolacrimal duct. Adenovirus produces deep orbital inflammation, in addition to infection of the conjunctival surface. PMID:26022084

  18. Gated magnetic resonance imaging of congenital cardiac malformations

    SciTech Connect

    Fletcher, B.D.; Jocobstein, M.D.; Nelson, A.D.; Riemenschneider, T.A.; Alfidi, R.J.

    1984-01-01

    Magnetic resonance (MR) images of a variety of cardiac malformations in 19 patients aged 1 week to 33 years were obtained using pulse plethysmographic- or ECG-gated spin echo pulse sequences. Coronal, axial, and sagittal images displaying intracardiac structures with excellent spatial and contrast resolution were acquired during systole or diastole. It is concluded that MR will be a valuable noninvasive method of diagnosing congenital heart disease.

  19. Basic principles of magnetic resonance imaging.

    PubMed

    Gibby, Wendell A

    2005-01-01

    We have come full circle from spinning quarks to 3D medical images. The bulk of MRI is now performed using slice-selective gradients, during which RF energy is applied to excite the hydrogen nuclei. By stepping a phase-encoding gradient during each TR and using a frequency-encoding gradient as the data are sampled, the 3D human object can be reduced to many individual points or voxels. By acquiring multiple slices at once, the time efficiency of imaging can be vastly improved. Many newer strategies use variations of this technique to acquire multiple lines of data during a single echo, enshrining spin warp imaging as the most important method of signal acquisition for MRI. PMID:15561528

  20. Magnetic Resonance Imaging-Guided Cardiac Interventions.

    PubMed

    Schmidt, Ehud J

    2015-11-01

    Performing intraoperative cardiovascular procedures inside an MR imaging scanner can potentially provide substantial advantage in clinical outcomes by reducing the risk and increasing the success rate relative to the way such procedures are performed today, in which the primary surgical guidance is provided by X-ray fluoroscopy, by electromagnetically tracked intraoperative devices, and by ultrasound. Both noninvasive and invasive cardiologists are becoming increasingly familiar with the capabilities of MR imaging for providing anatomic and physiologic information that is unequaled by other modalities. As a result, researchers began performing animal (preclinical) interventions in the cardiovascular system in the early 1990s. PMID:26499275

  1. [Magnetic resonance imaging of the brain].

    PubMed

    Koob, Mériam; Dietemann, Jean-Louis

    2007-03-01

    MRI uses the magnetic properties of the hydrogen atoms present in the human body. It presents no risks as long as the contraindications (pacemaker, metal fragment in the eye, pregnancy less than 3 months) are complied with. MRI is the reference imaging method for exploration of the brain. The contrast of these images depends on the type of sequence used. More specific sequences (diffusio-weighted, gradient echo) and gadolinium injection can be added to the basic sequences (T1, T2, Flair). PMID:17336858

  2. Cerebral response to `voiceness': a functional magnetic resonance imaging study

    E-print Network

    of musical instruments.The voice-selective areas of the left and right superior temporal sulcus did not show the expected relation between `voiceness' and size e¡ect. Instead, superior temporal sulcus activity seemed morphing, functional magnetic resonance imaging, naturalness, superior temporal sulcus, voice perception

  3. Sodium Magnetic Resonance Imaging: From Research to Clinical Use

    E-print Network

    Ouwerkerk, Ronald

    Sodium Magnetic Resonance Imaging: From Research to Clinical Use Ronald Ouwerkerk, PhD INTRODUCTION of those techniques that at first glance seemed to be very promising. Sodium MRI has the potential] is based on significant changes in tissue sodium concentration (TSC). For stroke in humans, an increase

  4. Principles of Magnetic Resonance Imaging. Matlab session 2 December 2012

    E-print Network

    Sleijpen, Gerard

    = 256. Define a test signal (for example, f=rand(N,1)) and check your code against the matlab functionPrinciples of Magnetic Resonance Imaging. Matlab session 2 December 2012 Exercise 1: 2D Discrete and ^f are the column vectors representing (fn) and ( ^fk), respectively. Implement D in Matlab for N

  5. Detection of Prostate Cancer from Multiparametric Magnetic Resonance Imaging

    E-print Network

    Freitas, Nando de

    050 051 052 053 Detection of Prostate Cancer from Multiparametric Magnetic Resonance Imaging Anonymous (MRI) based technique of detecting prostate cancer is developed. A machine learning algorithm, based. The classifier is trained to detect prostate cancer in the peripheral zone and using the trained classifier

  6. RECONSTRUCTION OF HUMAN LUNG MORPHOLOGY MODELS FROM MAGNETIC RESONANCE IMAGES

    EPA Science Inventory


    Reconstruction of Human Lung Morphology Models from Magnetic Resonance Images
    T. B. Martonen (Experimental Toxicology Division, U.S. EPA, Research Triangle Park, NC 27709) and K. K. Isaacs (School of Public Health, University of North Carolina, Chapel Hill, NC 27514)

  7. Functional Connectivity Magnetic Resonance Imaging Classification of Autism

    ERIC Educational Resources Information Center

    Anderson, Jeffrey S.; Nielsen, Jared A.; Froehlich, Alyson L.; DuBray, Molly B.; Druzgal, T. Jason; Cariello, Annahir N.; Cooperrider, Jason R.; Zielinski, Brandon A.; Ravichandran, Caitlin; Fletcher, P. Thomas; Alexander, Andrew L.; Bigler, Erin D.; Lange, Nicholas; Lainhart, Janet E.

    2011-01-01

    Group differences in resting state functional magnetic resonance imaging connectivity between individuals with autism and typically developing controls have been widely replicated for a small number of discrete brain regions, yet the whole-brain distribution of connectivity abnormalities in autism is not well characterized. It is also unclear…

  8. Modeling Left Ventricle Wall Motion Using Tagged Magnetic Resonance Imaging

    E-print Network

    Alenezy, Mohammed D.

    2009-04-17

    A two-parameter computational model is proposed for the study of the regional motion of the left ventricle (LV) wall using tagged magnetic resonance imaging (tMRI) data. In this model, the LV wall motion is mathematically decomposed into two...

  9. Introduction Computerized axial tomography (CAT) and magnetic resonance imaging (MRI)

    E-print Network

    Hamann, Bernd

    -dimensional pictures. Scanning a human's head, CAT produces slices taken perpendicular to the spine. Each sliceChapter 1 Introduction Computerized axial tomography (CAT) and magnetic resonance imaging (MRI powerful tool in diagnosis. #12; 2 Fig. 1.1. Axial and saggital slice of human head (CAT). CAT and MRI

  10. Three-Dimensional Magnetic Resonance Imaging of Velopharyngeal Structures

    ERIC Educational Resources Information Center

    Bae, Youkyung; Kuehn, David P.; Sutton, Bradley P.; Conway, Charles A.; Perry, Jamie L.

    2011-01-01

    Purpose: To report the feasibility of using a 3-dimensional (3D) magnetic resonance imaging (MRI) protocol for examining velopharyngeal structures. Using collected 3D MRI data, the authors investigated the effect of sex on the midsagittal velopharyngeal structures and the levator veli palatini (levator) muscle configurations. Method: Ten Caucasian…

  11. Chromatic Light Adaptation Measured using Functional Magnetic Resonance Imaging

    E-print Network

    Wandell, Brian A.

    and spectral sensitivity of light adaptation. The behavioral color literature contains many measurements (ERG) in the human eye and concluded that significant light adaptation can be measured usingChromatic Light Adaptation Measured using Functional Magnetic Resonance Imaging Alex R. Wade

  12. Noninvasive Imaging of Head-Brain Conductivity Profiles Using Magnetic Resonance Electrical Impedance Imaging

    PubMed Central

    Zhang, Xiaotong; Yan, Dandan; Zhu, Shanan; He, Bin

    2008-01-01

    Magnetic resonance electrical impedance tomography (MREIT) is a recently introduced non-invasive conductivity imaging modality, which combines the magnetic resonance current density imaging (CDI) and the traditional electrical impedance tomography (EIT) techniques. MREIT is aimed at providing high spatial resolution images of electrical conductivity, by avoiding solving the well-known ill-posed problem in the traditional EIT. In this paper, we review our research activities in MREIT imaging of head-brain tissue conductivity profiles. We have developed several imaging algorithms and conducted a series of computer simulations for MREIT imaging of the head and brain tissues. Our work suggests MREIT brain imaging may become a useful tool in imaging conductivity distributions of the brain and head. PMID:18799394

  13. Metabolic imaging of multiple x-nucleus resonances.

    PubMed

    Steinseifer, Isabell K; Wijnen, Jannie P; Hamans, Bob C; Heerschap, Arend; Scheenen, Tom W J

    2013-07-01

    This study describes a technique for fast imaging of x-nuclei metabolites. Due to increased sensitivity and larger chemical shift dispersion at high magnetic fields, images of multiple metabolites can be obtained simultaneously by selective excitation of their resonances with a multifrequency selective radiofrequency pulse at any desired flip angle. This aim is achieved by combining a three-dimensional gradient echo imaging sequence with a Shinnar-LeRoux optimized excitation pulse. A proper choice of bandwidth, imaging matrix size, and field of view allows using the chemical shift dispersion of the different resonances to completely separate their images within one large field of view. The method of fast metabolic imaging is illustrated with (13)C measurements of a phantom containing a solution of (13)C labeled glucose, lactate, and sodium octanoate and by dynamic measurements of the (31)P metabolites phosphocreatine and ?-adenosine triphosphate in human femoral muscle in vivo, both at 7T. With dynamic selective (31)P imaging of the larger part of the upper leg, phosphocreatine signal intensity changes of specific muscles can be studied simultaneously by analyzing the sum of phosphocreatine signals within arbitrarily shaped regions of interest following the muscles' contours. This concept of dynamic metabolic imaging can be applied to other organs and further expanded to other MR-detectable nuclei and metabolites. PMID:22886743

  14. Magnetic Resonance Imaging as a Biomarker for Renal Cell Carcinoma

    PubMed Central

    Wu, Yan; Kwon, Young Suk; Labib, Mina; Foran, David J.; Singer, Eric A.

    2015-01-01

    As the most common neoplasm arising from the kidney, renal cell carcinoma (RCC) continues to have a significant impact on global health. Conventional cross-sectional imaging has always served an important role in the staging of RCC. However, with recent advances in imaging techniques and postprocessing analysis, magnetic resonance imaging (MRI) now has the capability to function as a diagnostic, therapeutic, and prognostic biomarker for RCC. For this narrative literature review, a PubMed search was conducted to collect the most relevant and impactful studies from our perspectives as urologic oncologists, radiologists, and computational imaging specialists. We seek to cover advanced MR imaging and image analysis techniques that may improve the management of patients with small renal mass or metastatic renal cell carcinoma. PMID:26609190

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

    ERIC Educational Resources Information Center

    Seedhouse, Steven J.; Hoffmann, Markus M.

    2008-01-01

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

  16. Fractal dimension of cerebral surfaces using magnetic resonance images

    SciTech Connect

    Majumdar, S.; Prasad, R.R.

    1988-11-01

    The calculation of the fractal dimension of the surface bounded by the grey matter in the normal human brain using axial, sagittal, and coronal cross-sectional magnetic resonance (MR) images is presented. The fractal dimension in this case is a measure of the convolutedness of this cerebral surface. It is proposed that the fractal dimension, a feature that may be extracted from MR images, may potentially be used for image analysis, quantitative tissue characterization, and as a feature to monitor and identify cerebral abnormalities and developmental changes.

  17. Surface plasmon resonance imaging for parallelized detection of protein biomarkers

    NASA Astrophysics Data System (ADS)

    Piliarik, Marek; Párová, Lucie; Vaisocherová, Hana; Homola, Ji?í

    2009-05-01

    We report a novel high-throughput surface plasmon resonance (SPR) biosensor for rapid and parallelized detection of protein biomarkers. The biosensor is based on a high-performance SPR imaging sensor with polarization contrast and internal referencing which yields a considerably higher sensitivity and resolution than conventional SPR imaging systems (refractive index resolution 2 × 10-7 RIU). We combined the SPR imaging biosensor with microspotting to create an array of antibodies. DNA-directed protein immobilization was utilized for the spatially resolved attachment of antibodies. Using Human Chorionic Gonadotropin (hCG) as model protein biomarker, we demonstrated the potential for simultaneous detection of proteins in up to 100 channels.

  18. Interactions between magnetic resonance imaging and dental material

    PubMed Central

    Mathew, Chalakuzhiyl Abraham; Maller, Sudhakara; Maheshwaran

    2013-01-01

    Magnetic resonance imaging (MRI) has become a common and important life-saving diagnostic tool in recent times, for diseases of the head and neck region. Dentists should be aware of the interactions of various restorative dental materials and different technical factors put to use by an MRI scanning machine. Specific knowledge about these impacts, at the dentist level and at the level of the personnel at the MRI centers can save valuable time for the patient and prevent errors in MRI images. Artifacts from metal restorations are a major hindrance at such times, as they result in disappearance or distortion of the image and loss of important information. PMID:23946562

  19. Magnetic resonance imaging of convection in laser-polarized xenon

    NASA Technical Reports Server (NTRS)

    Mair, R. W.; Tseng, C. H.; Wong, G. P.; Cory, D. G.; Walsworth, R. L.

    2000-01-01

    We demonstrate nuclear magnetic resonance (NMR) imaging of the flow and diffusion of laser-polarized xenon (129Xe) gas undergoing convection above evaporating laser-polarized liquid xenon. The large xenon NMR signal provided by the laser-polarization technique allows more rapid imaging than one can achieve with thermally polarized gas-liquid systems, permitting shorter time-scale events such as rapid gas flow and gas-liquid dynamics to be observed. Two-dimensional velocity-encoded imaging shows convective gas flow above the evaporating liquid xenon, and also permits the measurement of enhanced gas diffusion near regions of large velocity variation.

  20. Comparative evolution of carotidynia on ultrasound and magnetic resonance imaging.

    PubMed

    Behar, T; Menjot, N; Laroche, J-P; Böge, B; Quéré, I; Galanaud, J-P

    2015-12-01

    Carotidynia is rare and associates neck pain with tenderness to palpation usually over the carotid bifurcation, the diagnosis of which is based on magnetic resonance imaging (MRI). Ultrasounds (US) are also frequently used but their accuracy in predicting the course of the disease is unknown. We are reporting the case of a 52-year-old man who presented a typical carotidynia. Clinical symptoms, ultrasound and MRI imaging evolution were closely correlated. Our case suggest that after a first MRI to set a positive diagnosis of carotidynia and exclude differential diagnoses, US which is more widely available and less expensive could constitute the imaging of reference for the follow-up. PMID:26163344

  1. Magnetic resonance imaging of pancreatic metastases from renal cell carcinoma.

    PubMed

    Sikka, Amrita; Adam, Sharon Z; Wood, Cecil; Hoff, Frederick; Harmath, Carla B; Miller, Frank H

    2015-01-01

    Pancreatic metastases are rare but are thought to be most commonly from renal cell carcinoma (RCC). These metastases can present many years after the initial tumor is resected, and accordingly, these patients require prolonged imaging follow-up. Although the computed tomographic findings of these metastases have been extensively reviewed in the literature, little has been written about the magnetic resonance imaging appearance of these metastases. Pancreatic metastases from RCC are typically T1 hypointense and T2 hyperintense. After intravenous administration of gadolinium, they are typically hypervascular and less commonly hypovascular. Chemical shift and diffusion-weighted imaging can aid in the diagnosis of these metastases. PMID:26324216

  2. Cardiac magnetic resonance imaging in children.

    PubMed

    Helbing, Willem A; Ouhlous, Mohamed

    2015-01-01

    MRI is an important additional tool in the diagnostic work-up of children with congenital heart disease. This review aims to summarise the role MRI has in this patient population. Echocardiography remains the main diagnostic tool in congenital heart disease. In specific situations, MRI is used for anatomical imaging of congenital heart disease. This includes detailed assessment of intracardiac anatomy with 2-D and 3-D sequences. MRI is particularly useful for assessment of retrosternal structures in the heart and for imaging large vessel anatomy. Functional assessment includes assessment of ventricular function using 2-D cine techniques. Of particular interest in congenital heart disease is assessment of right and single ventricular function. Two-dimensional and newer 3-D techniques to quantify flow in these patients are or will soon become an integral part of quantification of shunt size, valve function and complex flow patterns in large vessels. More advanced uses of MRI include imaging of cardiovascular function during stress and tissue characterisation of the myocardium. Techniques used for this purpose need further validation before they can become part of the daily routine of MRI assessment of congenital heart disease. PMID:25552387

  3. A new imaging technique based on resonance for arterial vessels

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoming; Fatemi, Mostafa; Greenleaf, James F.

    2003-04-01

    Vibro-acoustography is a new noncontact imaging method based on the radiation force of ultrasound. We extend this technique for imaging of arterial vessels based on vibration resonance. The arterial vessel is excited remotely by ultrasound at a resonant frequency, at which the vibration of the vessel as well as its transmission to the body surface are large enough to be measured. By scanning the ultrasound beam across the vessel plane and measuring the vibration at one single point on the body or vessel surface, an image of the interior artery can be mapped. Theory is developed that predicts the measured velocity is proportional to the value of the mode shape at resonance. Experimental studies were carried out on a silicone tube embedded in a cylindrical gel phantom of large radius, which simulates a large artery and the surrounding body. The fundamental frequency was measured at which the ultrasound transducer scanned across the tube plane with velocity measurement at one single point on the tube or on the phantom by laser. The images obtained show clearly the interior tube and the modal shape of the tube. The present technique offers a new imaging method for arterial vessels.

  4. Para-Hydrogen-Enhanced Gas-Phase Magnetic Resonance Imaging

    SciTech Connect

    Bouchard, Louis-S.; Kovtunov, Kirill V.; Burt, Scott R.; Anwar,M. Sabieh; Koptyug, Igor V.; Sagdeev, Renad Z.; Pines, Alexander

    2007-02-23

    Herein, we demonstrate magnetic resonance imaging (MRI) inthe gas phase using para-hydrogen (p-H2)-induced polarization. A reactantmixture of H2 enriched in the paraspin state and propylene gas is flowedthrough a reactor cell containing a heterogenized catalyst, Wilkinson'scatalyst immobilized on modified silica gel. The hydrogenation product,propane gas, is transferred to the NMR magnet and is spin-polarized as aresult of the ALTADENA (adiabatic longitudinal transport and dissociationengenders net alignment) effect. A polarization enhancement factor of 300relative to thermally polarized gas was observed in 1D1H NMR spectra.Enhancement was also evident in the magnetic resonance images. This isthe first demonstration of imaging a hyperpolarized gaseous productformed in a hydrogenation reaction catalyzed by a supported catalyst.This result may lead to several important applications, includingflow-through porous materials, gas-phase reaction kinetics and adsorptionstudies, and MRI in low fields, all using catalyst-free polarizedfluids.

  5. Magnetic resonance imaging: Atlas of the head, neck and spine

    SciTech Connect

    Mills, C.M.; De Groot, J.; Posin, J.P.

    1987-01-01

    The purpose of this atlas is to provide the reader with a means to complement existing sources of information and to correlate the superb soft tissue contrast realized in magnetic resonance images with the appropriate anatomic and functional structures. Where appropriate, pathologic examples have been included to complement normal images. In addition, since MRI (magnetic resonance imaging) clearly separates gray from white matter, and thus accurately visualizes the position of functional tracts as they extend from cortex to spinal cord, a separate section on functional neuroanatomy has been provided. Likewise, the improved visualization of vascular structures and associated pathologic processes has led to the inclusion of vascular anatomy and associated perfusion territories. These additions will be of particular use in clinical practice, as precise lesion identification and localization can now be correlated to specific clinical symptomatology.

  6. Magnetic resonance imaging for image-guided implantology

    NASA Astrophysics Data System (ADS)

    Eggers, Georg; Kress, Bodo; Fiebach, Jochen; Rieker, Marcus; Spitzenberg, Doreen; Marmulla, Rüdiger; Dickhaus, Hartmut; Mühling, Joachim

    2006-03-01

    Image guided implantology using navigation systems is more accurate than manual dental implant insertion. The underlying image data are usually derived from computer tomography. The suitability of MR imaging for dental implant planning is a marginal issue so far. MRI data from cadaver heads were acquired using various MRI sequences. The data were assessed for the quality of anatomical imaging, geometric accuracy and susceptibility to dental metal artefacts. For dental implant planning, 3D models of the jaws were created. A software system for segmentation of the mandible and maxilla MRI data was implemented using c++, mitk, and qt. With the VIBE_15 sequence, image data with high geometric accuracy were acquired. Dental metal artefacts were lower than in CT data of the same heads. The segmentation of the jaws was feasible, in contrast to the segmentation of the dentition, since there is a lack of contrast to the intraoral soft tissue structures. MRI is a suitable method for imaging of the region of mouth and jaws. The geometric accuracy is excellent and the susceptibility to artefacts is low. However, there are yet two limitations: Firstly, the imaging of the dentition needs further improvement to allow accurate segmentation of these regions. Secondly, the sequence used in this study takes several minutes and hence is susceptible to motion artefacts.

  7. Instrumentation for parallel magnetic resonance imaging 

    E-print Network

    Brown, David Gerald

    2007-04-25

    field. This image is formed by the application of a series of RF and static magnetic field gradient pulses (a pulse sequence) which interact with the nuclear magnetic dipoles, or spins, contained within the sample. Pulse sequences are used to scan...) process of assembling the prototype 64-channel parallel receiver system. IGC, Inc. is also gratefully acknowledged for its generous donation of a 0.16 T, whole body, permanent magnet. The IGC magnet was used as a testbed for the development of RF coils...

  8. SEVEN TOPICS IN FUNCTIONAL MAGNETIC RESONANCE IMAGING

    PubMed Central

    BANDETTINI, PETER A.

    2010-01-01

    Functional MRI (fMRI) is a non-invasive brain imaging methodology that started in 1991 and allows human brain activation to be imaged at high resolution within only a few minutes. Because it has extremely high sensitivity, is relatively easy to implement, and can be performed on most standard clinical MRI scanners. It continues to grow at an explosive rate throughout the world. Over the years, at any given time, fMRI has been defined by only a handful of major topics that have been the focus of researchers using and developing the methodology. In this review, I attempt to take a snapshot of the field of fMRI as it is in mid-2009 by discussing the seven topics that I feel are most on the minds of fMRI researchers. The topics are, in no particular order or grouping: (1) Clinical impact, (2) Utilization of individual functional maps, (3) fMRI signal interpretation, (4) Pattern effect mapping and decoding, (5) Endogenous oscillations, (6) MRI technology, and (7) Alternative functional contrast mechanisms. Most of these topics are highly interdependent, each advancing as the others advance. While most fMRI involves applications towards clinical or neuroscience questions, all applications are fundamentally dependent on advances in basic methodology as well as advances in our understanding of the relationship between neuronal activity and fMRI signal changes. This review neglects almost completely an in-depth discussion of applications. Rather the discussions are on the methods and interpretation. PMID:19938211

  9. Superconducting magnets for whole body magnetic resonance imaging

    SciTech Connect

    Murphy, M.F.

    1989-03-01

    Superconducting magnets have achieved preeminence in the magnetic resonance imaging (MRI) industry. Further growth in this market will depend on reducing system costs, extending medical applications, and easing the present siting problem. New magnet designs from Oxford address these issues. Compact magnets are economical to build and operate. Two 4 Tesla whole body magnets for research in magnetic resonance spectroscopy (MRS) are now in operation. Active-Shield magnets, by drastically reducing the magnetic fringe fields, will allow MRI systems with superconducting magnets to be located in previously inaccessible sites.

  10. Functional magnetic resonance imaging in medicine and physiology

    SciTech Connect

    Moonen, C.T.W.; van Zijl, P.C.M.; Frank, J.A.; Bihan, D.L.; Becker, E.D. )

    1990-10-05

    Magnetic resonance imaging (MRI) is a well-established diagnostic tool that provides detailed information about macroscopic structure and anatomy. Recent advances in MRI allow the noninvasive spatial evaluation of various biophysical and biochemical processes in living systems. Specifically, the motion of water can be measured in processes such as vascular flow, capillary flow, diffusion, and exchange. In addition, the concentrations of various metabolites can be determined for the assessment of regional regulation of metabolism. Examples are given that demonstrate the use of functional MRI for clinical and research purposes. This development adds a new dimension to the application of magnetic resonance to medicine and physiology.

  11. Rapid, Embeddable Design Method for Spiral Magnetic Resonance Image Reconstruction Resampling Kernels

    E-print Network

    Sekerinski, Emil

    Rapid, Embeddable Design Method for Spiral Magnetic Resonance Image Reconstruction Resampling Abstract. After formulating the design problem for Resampling Kernels used in Magnetic Resonance Spi- ral resonance imaging, spiral imaging, regridding, non-uniform Fourier transform, inte- rior point method 1

  12. The Multisensory Attentional Consequences of Tool Use: A Functional Magnetic Resonance Imaging Study

    E-print Network

    Miall, Chris

    The Multisensory Attentional Consequences of Tool Use: A Functional Magnetic Resonance Imaging functional magnetic resonance imaging, while they used a simple tool to discriminate between target) The Multisensory Attentional Consequences of Tool Use: A Functional Magnetic Resonance Imaging Study. PLoS ONE 3

  13. Subnanometre resolution in three-dimensional magnetic resonance imaging of individual

    E-print Network

    Yacoby, Amir

    Subnanometre resolution in three-dimensional magnetic resonance imaging of individual dark spins M. Hong4 , P. Maletinsky2 and A. Yacoby1 * Magnetic resonance imaging (MRI) has revolutionized bio, and determining the location of spin labels in biological systems. Magnetic resonance imaging (MRI) on the atomic

  14. Intracranial Boundary Detection and Radio Frequency Correction in Magnetic Resonance Images

    E-print Network

    Atkins, M. Stella

    Intracranial Boundary Detection and Radio Frequency Correction in Magnetic Resonance Images Boundary Detection and Radio Frequency Cor­ rection in Magnetic Resonance Images Examining Committee: Dr. A Date Approved: ii #12; Abstract Magnetic resonance imaging (MRI) is a noninvasive method for producing

  15. Bayesian Spatiotemporal Modeling using Hierarchical Spatial Priors with Applications to Functional Magnetic Resonance Imaging

    E-print Network

    Jones, Galin

    Magnetic Resonance Imaging Martin Bezener School of Statistics University of Minnesota, Twin Cities martin@umn.edu December 9, 2014 Abstract Functional magnetic resonance imaging (fMRI) has recently become a popular tool functional magnetic resonance imaging (fMRI) experiments that consist of presenting tasks to a subject

  16. Magnetic Resonance Imaging 1 A new global optimization algorithm and its application to a

    E-print Network

    Neumaier, Arnold

    Magnetic Resonance Imaging 1 A new global optimization algorithm and its application to a Magnetic-cost, low-field multipolar magnet for Magnetic Resonance Imaging with a high field uniformity with probability one. Key Words: Magnetic Resonance Imaging, global optimization, simulated annealing, derivative

  17. Event-related functional magnetic resonance imaging: modelling, inference and optimization

    E-print Network

    Henson, Rik

    Event-related functional magnetic resonance imaging: modelling, inference and optimization Oliver, 10 Queen Square, London WC1N 3BG, UK Event-related functional magnetic resonance imaging is a recent. With these models in mind, we then consider how the properties of functional magnetic resonance imaging data

  18. Fiber Tractography in Diffusion Tensor Magnetic Resonance Imaging: A Survey and Beyond

    E-print Network

    Zhang, Jun

    1 Fiber Tractography in Diffusion Tensor Magnetic Resonance Imaging: A Survey and Beyond Jun Zhang, 2005 Abstract Diffusion tensor magnetic resonance imaging (DT-MRI) is the first noninvasive in vivo tensor magnetic resonance imaging, fiber tractography, streamline tracking, anisotropic diffusion

  19. Technical Note Graph-partitioned spatial priors for functional magnetic resonance images

    E-print Network

    Penny, Will

    Technical Note Graph-partitioned spatial priors for functional magnetic resonance images L 23 August 2008 Keywords: High-resolution functional magnetic resonance images Graph of functional magnetic resonance imaging (fMRI) data allow one to estimate the spatial smoothness of general

  20. INTERACTIVE SEGMENTATION OF THE HIPPOCAMPUS FROM MAGNETIC RESONANCE IMAGES USING DEFORMABLE SHAPE TEMPLATES

    E-print Network

    Subramanian, Kalpathi R.

    INTERACTIVE SEGMENTATION OF THE HIPPOCAMPUS FROM MAGNETIC RESONANCE IMAGES USING DEFORMABLE SHAPE William Vann Hasty Jr. Interactive Segmentation of the Hippocampus from Magnetic Resonance Images Using of hippocampi with a reliable semi­automatic techniques. Magnetic resonance imaging provides a non­ invasive

  1. A Bayesian TimeCourse Model for Functional Magnetic Resonance Imaging Data

    E-print Network

    Genovese, Christopher

    A Bayesian Time­Course Model for Functional Magnetic Resonance Imaging Data Christopher R. Genovese Functional Magnetic Resonance Imaging (fMRI) is a new technique for studying the workings of the active human brain. During an fMRI ex­ periment, a sequence of Magnetic Resonance images is acquired while a subject

  2. ACCELERATED PARALLEL MAGNETIC RESONANCE IMAGING RECONSTRUCTION USING JOINT ESTIMATION WITH A SPARSE SIGNAL MODEL

    E-print Network

    Goyal, Vivek K

    ACCELERATED PARALLEL MAGNETIC RESONANCE IMAGING RECONSTRUCTION USING JOINT ESTIMATION WITH A SPARSE, increasing peak-signal-to-noise ra- tio by up to 10 dB. Index Terms-- Magnetic resonance imaging, image re.grady@siemens.com, wald@nmr.mgh.harvard.edu, elfar@mit.edu, vgoyal@mit.edu ABSTRACT Accelerating magnetic resonance

  3. Magnetic resonance imaging of laser polarized liquid xenon C. H. Tseng,1,2

    E-print Network

    Walsworth, Ronald L.

    Magnetic resonance imaging of laser polarized liquid xenon C. H. Tseng,1,2 R. W. Mair,1 G. P. Wong, Massachusetts 02115 Received 5 August 1998 We demonstrate magnetic resonance imaging MRI of laser polarized of polarized xenon for use in gas phase magnetic resonance imaging MRI 5 ; and, as re- ported in this paper

  4. Magnetic Resonance Imaging (MRI) of Oak Trees Infected With Phytophthora ramorum to

    E-print Network

    91 Magnetic Resonance Imaging (MRI) of Oak Trees Infected With Phytophthora ramorum to Determine as an avenue of infection for P. ramorum. Key words: magnetic resonance imaging, microscopy, periderm. It was determined that high resolution Magnetic Resonance Imaging (MRI) would be a valuable technology that could

  5. Introduction to Magnetic Resonance Imaging Fall 2014, Tuesday/Thursday 11:00-12:15

    E-print Network

    Geller, Michael R.

    Introduction to Magnetic Resonance Imaging Fall 2014, Tuesday/Thursday 11:00-12:15 Course number: To provide basic knowledge to understand modern methods of Magnetic Resonance Imaging (MRI) physics will provide an introductory treatment of current magnetic resonance imaging physics and methods for living

  6. Automatic Segmentation of Non-enhancing Brain Tumors in Magnetic Resonance Images

    E-print Network

    Hall, Lawrence O.

    Automatic Segmentation of Non-enhancing Brain Tumors in Magnetic Resonance Images Lynn M. Fletcher,hall,goldgof@csee.usf.edu, murtagh@rad.usf.edu. #12;2 Abstract Tumor segmentation from magnetic resonance MR images may aid in tumor processing, automatic tissue classi cation, fuzzy, clustering I. Introduction Magnetic resonance imaging MRI

  7. Spatially encoded NMR and the acquisition of 2D magnetic resonance images within a single scan

    E-print Network

    Frydman, Lucio

    Spatially encoded NMR and the acquisition of 2D magnetic resonance images within a single scan Yoav acquisition schemes toward the collection of two-dimen- sional magnetic resonance imaging (2D MRI) data resonance imaging (MRI). In spite of the dissimilar information being sought in 2D NMR and 2D MRI

  8. Magnetic resonance imaging of perfusion diffusion mismatch in rodent and non-human

    E-print Network

    Duong, Timothy Q.

    Review Magnetic resonance imaging of perfusion­ diffusion mismatch in rodent and non-human primate of death and long-term disability. Non-invasive magnetic resonance imaging (MRI) has been widely used-human primates. Keywords: Magnetic resonance imaging, Perfusion­diffusion mismatch, Apparent diffusion

  9. CBME Seminar Seminar Title: Cardiac Flow Analysis Based on Magnetic Resonance Imaging

    E-print Network

    Balasuriya, Sanjeeva

    CBME Seminar Seminar Title: Cardiac Flow Analysis Based on Magnetic Resonance Imaging Presenter: Dr using a series of time dependent magnetic resonance images. An indication of flow vortices can resonance imaging (CMRI) provide a non-invasive approach for scanning humans with heart abnormalities

  10. Magneto-inductive catheter receiver for magnetic resonance imaging.

    PubMed

    Syms, Richard R A; Young, Ian R; Ahmad, Munir M; Taylor-Robinson, Simon D; Rea, Marc

    2013-09-01

    A catheter-based RF receiver for internal magnetic resonance imaging is demonstrated. The device consists of a double-sided thin-film circuit, wrapped around a hollow catheter and sealed in place with heat-shrink tubing. Signals are detected using a resonant LC circuit at the catheter tip and transmitted along the catheter using an array of coupled LC circuits arranged as a magneto-inductive waveguide, a form of low frequency metamaterial. Coupling to a conventional RF system is accomplished using a demountable inductive transducer. Protection against external B 1 and E fields is obtained by using figure-of-eight elements with an electrical length shorter than that of an immersed dipole. The system is primarily designed for biliary imaging, can pass the biopsy channel of a side-opening duodenoscope, and is guidewire-compatible, potentially allowing clinicians to implement MR image guided procedures without changing their standard practice. Decoupling against B 1 and E fields is verified, and in vitro (1)H magnetic resonance imaging with submillimeter resolution is demonstrated at 1.5 T using phantoms. PMID:23591471

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

    ERIC Educational Resources Information Center

    Grey, Michael L.

    2009-01-01

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

  12. Application of neurite orientation dispersion and density imaging (NODDI) to a tau pathology model of Alzheimer's disease.

    PubMed

    Colgan, N; Siow, B; O'Callaghan, J M; Harrison, I F; Wells, J A; Holmes, H E; Ismail, O; Richardson, S; Alexander, D C; Collins, E C; Fisher, E M; Johnson, R; Schwarz, A J; Ahmed, Z; O'Neill, M J; Murray, T K; Zhang, H; Lythgoe, M F

    2016-01-15

    Increased hyperphosphorylated tau and the formation of intracellular neurofibrillary tangles are associated with the loss of neurons and cognitive decline in Alzheimer's disease, and related neurodegenerative conditions. We applied two diffusion models, diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI), to in vivo diffusion magnetic resonance images (dMRI) of a mouse model of human tauopathy (rTg4510) at 8.5months of age. In grey matter regions with the highest degree of tau burden, microstructural indices provided by both NODDI and DTI discriminated the rTg4510 (TG) animals from wild type (WT) controls; however only the neurite density index (NDI) (the volume fraction that comprises axons or dendrites) from the NODDI model correlated with the histological measurements of the levels of hyperphosphorylated tau protein. Reductions in diffusion directionality were observed when implementing both models in the white matter region of the corpus callosum, with lower fractional anisotropy (DTI) and higher orientation dispersion (NODDI) observed in the TG animals. In comparison to DTI, histological measures of tau pathology were more closely correlated with NODDI parameters in this region. This in vivo dMRI study demonstrates that NODDI identifies potential tissue sources contributing to DTI indices and NODDI may provide greater specificity to pathology in Alzheimer's disease. PMID:26505297

  13. The use of modern imaging techniques in the diagnosis and treatment planning of patients with orbital floor fractures

    PubMed Central

    Loba, Piotr; Kozakiewicz, Marcin; Elgalal, Marcin; Stefa?czyk, Ludomir; Broniarczyk-Loba, Anna; Omulecki, Wojciech

    2011-01-01

    Summary Background Ocular motility impairment associated with orbital trauma may have several causes and manifest with various clinical symptoms. In some cases orbital reconstructive surgery can be very challenging and the results are often unsatisfactory. The use of modern imaging techniques aids proper diagnosis and surgical planning. Case Report The authors present the case of a 29-year-old male who sustained trauma to the left orbit. Orthoptic examination revealed limited supra- and infraduction of the left eye. The patient reported diplopia in upgaze and downgaze with primary position spared. Dynamic magnetic resonance imaging (dMRI) was performed, which revealed restriction of the left inferior rectus muscle in its central section. A patient-specific anatomical model was prepared on the basis of 3-dimensional computed tomography (CT) study of the intact orbit, which was used to prepare a custom pre-bent titanium mesh implant. The patient underwent reconstructive surgery of the orbital floor. Conclusions Modern imaging techniques such as dMRI and 3-dimensional CT reconstruction allow us to better understand the pathophysiology of orbital floor fractures and to precisely plan surgical treatment. PMID:21804469

  14. Robust Intensity Standardization in Brain Magnetic Resonance Images.

    PubMed

    De Nunzio, Giorgio; Cataldo, Rosella; Carlà, Alessandra

    2015-12-01

    The paper is focused on a tiSsue-Based Standardization Technique (SBST) of magnetic resonance (MR) brain images. Magnetic Resonance Imaging intensities have no fixed tissue-specific numeric meaning, even within the same MRI protocol, for the same body region, or even for images of the same patient obtained on the same scanner in different moments. This affects postprocessing tasks such as automatic segmentation or unsupervised/supervised classification methods, which strictly depend on the observed image intensities, compromising the accuracy and efficiency of many image analyses algorithms. A large number of MR images from public databases, belonging to healthy people and to patients with different degrees of neurodegenerative pathology, were employed together with synthetic MRIs. Combining both histogram and tissue-specific intensity information, a correspondence is obtained for each tissue across images. The novelty consists of computing three standardizing transformations for the three main brain tissues, for each tissue class separately. In order to create a continuous intensity mapping, spline smoothing of the overall slightly discontinuous piecewise-linear intensity transformation is performed. The robustness of the technique is assessed in a post hoc manner, by verifying that automatic segmentation of images before and after standardization gives a high overlapping (Dice index >0.9) for each tissue class, even across images coming from different sources. Furthermore, SBST efficacy is tested by evaluating if and how much it increases intertissue discrimination and by assessing gaussianity of tissue gray-level distributions before and after standardization. Some quantitative comparisons to already existing different approaches available in the literature are performed. PMID:25708893

  15. Elastomeric actuator devices for magnetic resonance imaging

    NASA Technical Reports Server (NTRS)

    Dubowsky, Steven (Inventor); Hafez, Moustapha (Inventor); Jolesz, Ferenc A. (Inventor); Kacher, Daniel F. (Inventor); Lichter, Matthew (Inventor); Weiss, Peter (Inventor); Wingert, Andreas (Inventor)

    2008-01-01

    The present invention is directed to devices and systems used in magnetic imaging environments that include an actuator device having an elastomeric dielectric film with at least two electrodes, and a frame attached to the actuator device. The frame can have a plurality of configurations including, such as, for example, at least two members that can be, but not limited to, curved beams, rods, plates, or parallel beams. These rigid members can be coupled to flexible members such as, for example, links wherein the frame provides an elastic restoring force. The frame preferably provides a linear actuation force characteristic over a displacement range. The linear actuation force characteristic is defined as .+-.20% and preferably 10% over a displacement range. The actuator further includes a passive element disposed between the flexible members to tune a stiffness characteristic of the actuator. The passive element can be a bi-stable element. The preferred embodiment actuator includes one or more layers of the elastomeric film integrated into the frame. The elastomeric film can be made of many elastomeric materials such as, for example, but not limited to, acrylic, silicone and latex.

  16. Application of Parallel Imaging to Murine Magnetic Resonance Imaging 

    E-print Network

    Chang, Chieh-Wei 1980-

    2012-09-21

    feed of this "dual-plane pair" element also eliminates the need for baluns in this case. The use of the element design in a 10-channel adjustable array coil for mouse imaging is presented, styled as a human cardiac top-bottom half-rack design...

  17. Improved Guided Image Fusion for Magnetic Resonance and Computed Tomography Imaging

    PubMed Central

    Jameel, Amina

    2014-01-01

    Improved guided image fusion for magnetic resonance and computed tomography imaging is proposed. Existing guided filtering scheme uses Gaussian filter and two-level weight maps due to which the scheme has limited performance for images having noise. Different modifications in filter (based on linear minimum mean square error estimator) and weight maps (with different levels) are proposed to overcome these limitations. Simulation results based on visual and quantitative analysis show the significance of proposed scheme. PMID:24695586

  18. The utility of cardiac magnetic resonance imaging in Kounis syndrome

    PubMed Central

    Okur, Aylin; Karaca, Leyla; Ogul, Hayri; Aköz, Ayhan; K?zrak, Yesim; Aslan, Sahin; Pirimoglu, Berhan; Aksakal, Enbiya; Emet, Mucahit

    2015-01-01

    Introduction Current diagnostic measurements used to assess myocardial involvement in Kounis syndrome, such as electrocardiography (ECG), cardiac enzymes, and troponin levels, are relatively insensitive to small but potentially significant functional change. According to our review of the literature, there has been no study using magnetic resonance imaging (MRI) on Kounis syndrome except for one case report. Aim To identify the findings of dynamic contrast-enhanced magnetic resonance imaging (CE-MRI) in patients with Kounis syndrome (KS) type 1. Material and methods We studied 26 patients (35 ±11.5 years, 53.8% male) with known or suspected KS type 1. The patients underwent precontrast, first-pass, and delayed enhancement cardiac MRI (DE-MRI). Contrast enhancement patterns, edema, hypokinesia, and localization for myocardial lesions were evaluated in all KS type 1 patients. Results Contrast-enhanced magnetic resonance imaging demonstrated an early-phase subendocardial contrast defect, and T2-weighted images showed high-signal intensity consistent with edema in lesion areas. None of the lesion areas was found upon contrast enhancement on DE-MRI. The area of early-phase subendocardial contrast defect was reported as follows: the interventricular septum in 14 (53.8%) patients, the left ventricular lateral wall in 8 (30.7%), and the left ventricular apex in 4 (15.4%). Conclusions Dynamic cardiac MR imaging is a reliable tool for assessing cardiac involvement in Kounis syndrome. Delayed contrast-enhanced images show normal washout in the subendocardial lesion area in patients with Kounis syndrome type 1. PMID:26677363

  19. Computed tomography and magnetic resonance imaging comparisons in boxers

    SciTech Connect

    Jordan, B.D. ); Zimmerman, R.D. )

    1990-03-23

    The efficacy of computed tomography (CT) and magnetic resonance imaging (MRI) in identifying traumatic injuries of the brain was compared in a referred population of 21 amateur and professional boxers. Three boxers displayed CT scans with equivocal findings that were verified as artifacts by MRI. Eleven boxers had both CT and MRI scans with normal findings, and 7 boxers had both CT and MRI scans with abnormal findings. There were no instances where abnormalities demonstrated on CT scanning were not detected by MRI. However, some abnormalities detected on MRI were not detected on CT scans. These included a subdural hematoma, white-matter changes, and a focal contusion. Magnetic resonance imaging appears to be the neuroradiodiagnostic test of choice compared with CT.

  20. Resonant imaging of carotenoid pigments in the human retina

    NASA Astrophysics Data System (ADS)

    Gellermann, Werner; Emakov, Igor V.; McClane, Robert W.

    2002-06-01

    We have generated high spatial resolution images showing the distribution of carotenoid macular pigments in the human retina using Raman spectroscopy. A low level of macular pigments is associated with an increased risk of developing age-related macular degeneration, a leading cause of irreversible blindness. Using excised human eyecups and resonant excitation of the pigment molecules with narrow bandwidth blue light from a mercury arc lamp, we record Raman images originating from the carbon-carbon double bond stretch vibrations of lutein and zeaxanthin, the carotenoids comprising human macular pigments. Our Raman images reveal significant differences among subjects, both in regard to absolute levels as well as spatial distribution within the macula. Since the light levels used to obtain these images are well below established safety limits, this technique holds promise for developing a rapid screening diagnostic in large populations at risk for vision loss from age-related macular degeneration.

  1. Signal Improvement and Contrast Enhancement in Magnetic Resonance Imaging

    E-print Network

    Han, Yi

    2015-01-01

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

  2. Magnetic resonance imaging of the internal auditory canal

    SciTech Connect

    Daniels, D.L.; Herfkins, R.; Koehler, P.R.; Millen, S.J.; Shaffer, K.A.; Williams, A.L.; Haughton, V.M.

    1984-04-01

    Three patients with exclusively or predominantly intracanalicular neuromas and 5 with presumably normal internal auditory canals were examined with prototype 1.4- or 1.5-tesla magnetic resonance (MR) scanners. MR images showed the 7th and 8th cranial nerves in the internal auditory canal. The intracanalicular neuromas had larger diameter and slightly greater signal strength than the nerves. Early results suggest that minimal enlargement of the nerves can be detected even in the internal auditory canal.

  3. Towards T1-limited magnetic resonance imaging using Rabi beats

    E-print Network

    H. Fedder; F. Dolde; F. Rempp; T. Wolf; P. Hemmer; F. Jelezko; J. Wrachtrup

    2010-09-03

    Two proof-of-principle experiments towards T1-limited magnetic resonance imaging with NV centers in diamond are demonstrated. First, a large number of Rabi oscillations is measured and it is demonstrated that the hyperfine interaction due to the NV's 14N can be extracted from the beating oscillations. Second, the Rabi beats under V-type microwave excitation of the three hyperfine manifolds is studied experimentally and described theoretically.

  4. Magnetic Resonance Imaging of Stroke in the Rat

    PubMed Central

    CHOPP, Michael; LI, Lian; ZHANG, Li; ZHANG, Zheng-gang; LI, Qing-jiang; JIANG, Quan

    2014-01-01

    Magnetic resonance imaging (MRI) is now a routine neuroimaging tool in the clinic. Throughout all phases of stroke from acute to chronic, MRI plays an important role to diagnose, evaluate and monitor the cerebral tissue undergoing stroke. This review provides a description of various MRI methods and an overview of selected MRI studies, with an embolic stroke model of rat, performed in the MRI laboratory of Department of Neurology, Henry Ford Hospital, Detroit, Michigan, US. PMID:24920874

  5. Bulk and surface sensitivity of a resonant waveguide grating imager

    NASA Astrophysics Data System (ADS)

    Orgovan, Norbert; Kovacs, Boglarka; Farkas, Eniko; Szabó, Bálint; Zaytseva, Natalya; Fang, Ye; Horvath, Robert

    2014-02-01

    We report the assessment of the sensitivity of a microplate-compatible resonant waveguide grating imager. The sensitivity to bulk refractive index changes was determined using a serial dilution of glycerol solution with the help of a refractometer. The surface sensitivity was examined using layer-by-layer polyelectrolyte films in conjunction with optical waveguide lightmode spectroscopy and characterized by the binding of acetazolamide to immobilized carbonic anhydrase under microfluidics. The results suggest that the imager has a limit of detection down to 2.2 × 10-6 for refractive index change and 0.078 ng/cm2 for the adsorbed mass.

  6. Magnetic resonance imaging of gel-cast ceramic composites

    SciTech Connect

    Dieckman, S.L.; Balss, K.M.; Waterfield, L.G.

    1997-04-01

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

  7. Overview of left ventricular outpouchings on cardiac magnetic resonance imaging

    PubMed Central

    Kumar, Sanjeev

    2015-01-01

    Left ventricular outpouchings commonly include aneurysm, pseudoaneurysm, and diverticulum and are now being increasingly detected on imaging. Distinction between these entities is of prime importance to guide proper management as outcomes for these entities differ substantially. Chest radiograph is usually nonspecific in their diagnosis. Echocardiography, multi-detector computed tomography evaluation and angiography are helpful in the diagnosis with their inherit limitations. Cardiac magnetic resonance imaging (MRI) is emerging as a very useful tool that allows simultaneous anatomical and functional evaluation along with tissue characterization, which has diagnostic, theraputic and prognostic implications. This article gives an overview of left ventricular outpouchings with special emphasis on their differentiation using cardiac MRI. PMID:26675616

  8. [Diffusion Weighted Magnetic Resonance Imaging and its Application in Ophthalmology].

    PubMed

    Lindner, T; Langner, S; Paul, K; Pohlmann, A; Hadlich, S; Niendorf, T; Jünemann, A; Guthoff, R F; Stachs, O

    2015-12-01

    The value of diffusion-weighted magnet resonance imaging (DWI-MRI) has been demonstrated for an ever growing range of clinical indications. DWI is sensitive to the diffusion of water molecules and probes their random displacement within tissue. DWI provides both qualitative and quantitative information on tissue characteristics, e.g. tissue cellularity. This review provides an overview of diffusion-weighted imaging and its emerging applications in ophthalmology. The basic physics and technical foundations of DWI are introduced. The emerging applications of DWI are surveyed, particularly in diseases of the eye, orbit and optical nerve. PMID:26678901

  9. Image force microscopy of molecular resonance: A microscope principle

    PubMed Central

    Rajapaksa, I.; Uenal, K.; Wickramasinghe, H. Kumar

    2010-01-01

    We demonstrate a technique in microscopy which extends the domain of atomic force microscopy to optical spectroscopy at the nanometer scale. We show that molecular resonance of feature sizes down to the single molecular level can be detected and imaged purely by mechanical detection of the force gradient between the interaction of the optically driven molecular dipole and its mirror image in a platinum coated scanning probe tip. This microscopy and spectroscopy technique is extendable to frequencies ranging from radio to infrared and the ultraviolet. PMID:20859536

  10. Current Role of Fetal Magnetic Resonance Imaging in Neurologic Anomalies.

    PubMed

    Lyons, Karen; Cassady, Christopher; Jones, Jeremy; Paldino, Michael; Mehollin-Ray, Amy; Guimaraes, Carolina; Krishnamurthy, Rajesh

    2015-08-01

    Magnetic resonance imaging (MRI) is used increasingly to image the fetus when important questions remain unanswered after ultrasonography, which might occur particularly with abnormal amniotic fluid volumes, difficult fetal lie or position, and maternal obesity. Ultrasonography also has limitations due to sound attenuation by bone, such as within the cranium and spine, and therefore MRI has a real advantage in delineating potentially complex neuroanatomical relationships. This article outlines current MRI protocols for evaluation of the fetal neural axis, describes indications for the use of MRI in the fetal brain and spine, and provides examples to illustrate the uses of available fetal sequences. PMID:26296481

  11. Calibration of a resonance energy transfer imaging system.

    PubMed Central

    Ludwig, M; Hensel, N F; Hartzman, R J

    1992-01-01

    A quantitative technique for the nondestructive visualization of nanometer scale intermolecular separations in a living system is described. A calibration procedure for the acquisition and analysis of resonance energy transfer (RET) image data is outlined. The factors limiting RET imaging of biological samples are discussed. Measurements required for the calibration include: (a) the spectral sensitivity of the image intensifier (or camera); (b) the transmission spectra of the emission filters; and (c) the quantum distribution functions of the energy transfer pair measured in situ. Resonance energy transfer imaging is demonstrated for two DNA specific dyes. The Förster critical distance for energy transfer between Hoechst 33342 (HO) and acridine orange (AO) is 4.5 +/- 0.7 nm. This distance is slightly greater than the distance of a single turn of the DNA helix (3.5 nm or approximately 10 base pairs), and is well below the optical diffraction limit. Timed sequences of intracellular energy transfer reveal nuclear structure, strikingly similar to that observed with confocal and electron microscopy, and may show the spatial distribution of eu- and hetero- chromatin in the interphase nuclei. Images FIGURE 6 PMID:1581499

  12. Microtesla magnetic resonance imaging with a superconducting quantum interference device

    SciTech Connect

    McDermott, Robert; Lee, SeungKyun; ten Haken, Bennie; Trabesinger, Andreas H.; Pines, Alexander; Clarke, John

    2004-03-15

    We have constructed a magnetic resonance imaging (MRI) scanner based on a dc Superconducting QUantum Interference Device (SQUID) configured as a second-derivative gradiometer. The magnetic field sensitivity of the detector is independent of frequency; it is therefore possible to obtain high-resolution images by prepolarizing the nuclear spins in a field of 300 mT and detecting the signal at 132 fYT, corresponding to a proton Larmor frequency of 5.6 kHz. The reduction in the measurement field by a factor of 10,000 compared with conventional scanners eliminates inhomogeneous broadening of the nuclear magnetic resonance lines, even in fields with relatively poor homogeneity. The narrow linewidths result in enhanced signal-to-noise ratio and spatial resolution for a fixed strength of the magnetic field gradients used to encode the image. We present two-dimensional images of phantoms and pepper slices, obtained in typical magnetic field gradients of 100 fYT/m, with a spatial resolution of about 1mm. We further demonstrate a slice-selected image of an intact pepper. By varying the time delay between removal of the polarizing field and initiation of the spin echo sequence we acquire T1-weighted contrast images of water phantoms, some of which are doped with a paramagnetic salt; here, T1 is the nuclear spin-lattice relaxation time. The techniques presented here could readily be adapted to existing multichannel SQUID systems used for magnetic source imaging of brain signals. Further potential applications include low-cost systems for tumor screening and imaging peripheral regions of the body.

  13. Spectrally Resolved Magnetic Resonance Imaging of the XenonBiosensor

    SciTech Connect

    Hilty, Christian; Lowery, Thomas; Wemmer, David; Pines, Alexander

    2005-07-15

    Due to its ability to non-invasively record images, as well as elucidate molecular structure, nuclear magnetic resonance is the method of choice for applications as widespread as chemical analysis and medical diagnostics. Its detection threshold is, however, limited by the small polarization of nuclear spins in even the highest available magnetic fields. This limitation can, under certain circumstances, be alleviated by using hyper-polarized substances. Xenon biosensors make use of the sensitivity gain of hyperpolarized xenon to provide magnetic resonance detection capability for a specific low-concentration target. They consist of a cryptophane cage, which binds one xenon atom, and which has been connected via a linker to a targeting moiety such as a ligand or antibody. Recent work has shown the possibility of using the xenon biosensor to detect small amounts of a substance in a heterogeneous environment by NMR. Here, we demonstrate that magnetic resonance (MR) provides the capability to obtain spectrally and spatially resolved images of the distribution of immobilized biosensor, opening the possibility for using the xenon biosensor for targeted imaging.

  14. A 64-channel personal computer based image reconstruction system and applications in single echo acquisition magnetic resonance elastography and ultra-fast magnetic resonance imaging

    E-print Network

    Yallapragada, Naresh

    2009-05-15

    Emerging technologies in parallel magnetic resonance imaging (MRI) with massive receiver arrays have paved the way for ultra-fast imaging at increasingly high frame rates. With the increase in the number of receiver channels used to implement...

  15. A functional magnetic resonance imaging study of the tradeo between semantics and phonology

    E-print Network

    A functional magnetic resonance imaging study of the tradeo¡ between semantics and phonology@haskins.yale.edu Received 31January 2005; accepted11February 2005 Using functional magnetic resonance imaging, we explored on the interaction of imageability with spelling-to-sound consistency for low-frequency words. Be- haviorally, high-imageable

  16. Respiratory Amplitude Guided 4-Dimensional Magnetic Resonance Imaging

    SciTech Connect

    Hu, Yanle; Caruthers, Shelton D.; Low, Daniel A.; Parikh, Parag J.; Mutic, Sasa

    2013-05-01

    Purpose: To evaluate the feasibility of prospectively guiding 4-dimensional (4D) magnetic resonance imaging (MRI) image acquisition using triggers at preselected respiratory amplitudes to achieve T{sub 2} weighting for abdominal motion tracking. Methods and Materials: A respiratory amplitude-based triggering system was developed and integrated into a commercial turbo spin echo MRI sequence. Initial feasibility tests were performed on healthy human study participants. Four respiratory states, the middle and the end of inhalation and exhalation, were used to trigger 4D MRI image acquisition of the liver. To achieve T{sub 2} weighting, the echo time and repetition time were set to 75 milliseconds and 4108 milliseconds, respectively. Single-shot acquisition, together with parallel imaging and partial k-space imaging techniques, was used to improve image acquisition efficiency. 4D MRI image sets composed of axial or sagittal slices were acquired. Results: Respiratory data measured and logged by the MRI scanner showed that the triggers occurred at the appropriate respiratory levels. Liver motion could be easily observed on both 4D MRI image datasets by sensing either the change of liver in size and shape (axial) or diaphragm motion (sagittal). Both 4D MRI image datasets were T{sub 2}-weighted as expected. Conclusions: This study demonstrated the feasibility of achieving T{sub 2}-weighted 4D MRI images using amplitude-based respiratory triggers. With the aid of the respiratory amplitude-based triggering system, the proposed method is compatible with most MRI sequences and therefore has the potential to improve tumor-tissue contrast in abdominal tumor motion imaging.

  17. Magnetic resonance imaging of the pelvic floor: from clinical to biomechanical imaging.

    PubMed

    Brandão, Sofia; Da Roza, Thuane; Parente, Marco; Ramos, Isabel; Mascarenhas, Teresa; Natal Jorge, Renato M

    2013-12-01

    This article reviews the current role of magnetic resonance imaging in the study of the pelvic floor anatomy and pelvic floor dysfunction. The application of static and dynamic magnetic resonance imaging in the clinical context and for biomechanical simulation modeling is assessed, and the main findings are summarized. Additionally, magnetic resonance-based diffusion tensor imaging is presented as a potential tool to evaluate muscle fiber morphology. In this article, focus is set on pelvic floor muscle damage related to urinary incontinence and pelvic organ prolapse, sometimes as a consequence of vaginal delivery. Modeling applications that evaluate anatomical and physiological properties of pelvic floor are presented to further illustrate their particular characteristics. Finally, finite element method is described as a method for modeling and analyzing pelvic floor structures' biomechanical performance, based on material and behavioral properties of the tissues, and considering pressure loads that mimic real-life conditions such as active contraction or Valsalva maneuver. PMID:24030164

  18. Development of a Hybrid Magnetic Resonance and Ultrasound Imaging System

    PubMed Central

    Sherwood, Victoria; Rivens, Ian; Collins, David J.; Leach, Martin O.; ter Haar, Gail R.

    2014-01-01

    A system which allows magnetic resonance (MR) and ultrasound (US) image data to be acquired simultaneously has been developed. B-mode and Doppler US were performed inside the bore of a clinical 1.5 T MRI scanner using a clinical 1–4?MHz US transducer with an 8-metre cable. Susceptibility artefacts and RF noise were introduced into MR images by the US imaging system. RF noise was minimised by using aluminium foil to shield the transducer. A study of MR and B-mode US image signal-to-noise ratio (SNR) as a function of transducer-phantom separation was performed using a gel phantom. This revealed that a 4?cm separation between the phantom surface and the transducer was sufficient to minimise the effect of the susceptibility artefact in MR images. MR-US imaging was demonstrated in vivo with the aid of a 2?mm VeroWhite 3D-printed spherical target placed over the thigh muscle of a rat. The target allowed single-point registration of MR and US images in the axial plane to be performed. The system was subsequently demonstrated as a tool for the targeting and visualisation of high intensity focused ultrasound exposure in the rat thigh muscle. PMID:25177702

  19. Magnetic Resonance Imaging in Ischemic Stroke and Cerebral Venous Thrombosis.

    PubMed

    Krieger, Daniel A; Dehkharghani, Seena

    2015-12-01

    Imaging is indispensable in the evaluation of patients presenting with central nervous system emergencies. Although computed tomography (CT) is the mainstay of initial assessment and triage, magnetic resonance imaging (MRI) has become vital in expanding diagnostic capabilities, refining management strategies, and developing our understanding of disease processes. Ischemic stroke and cerebral venous thrombosis are 2 areas wherein MRI is actively revolutionizing patient care. Familiarity with the imaging manifestations of these 2 disease processes is crucial for any radiologist reading brain MR studies. In this review, the fundamentals of image interpretation will be addressed in-depth. Furthermore, advanced imaging techniques which are redefining the role of emergency MRI will be outlined, with a focus on the pathophysiological mechanisms that underlie image interpretation. In particular, emerging data surrounding the use of MR perfusion imaging in acute stroke management portend dramatic shifts in neurointerventional management. To this end, a review of the recent stroke literature will hopefully enhance the radiologist's role in both meaningful reporting and multidisciplinary teamwork. PMID:26636639

  20. Current role of multiparametric magnetic resonance imaging for prostate cancer

    PubMed Central

    Chevallier, Olivier; Moulin, Morgan; Favelier, Sylvain; Genson, Pierre-Yves; Pottecher, Pierre; Crehange, Gilles; Cochet, Alexandre; Cormier, Luc

    2015-01-01

    Multiparametric magnetic resonance imaging (mp-MRI) has shown promising results in diagnosis, localization, risk stratification and staging of clinically significant prostate cancer, and targeting or guiding prostate biopsy. mp-MRI consists of T2-weighted imaging (T2WI) combined with several functional sequences including diffusion-weighted imaging (DWI), perfusion or dynamic contrast-enhanced imaging (DCEI) and spectroscopic imaging. Recently, mp-MRI has been used to assess prostate cancer aggressiveness and to identify anteriorly located tumors before and during active surveillance. Moreover, recent studies have reported that mp-MRI is a reliable imaging modality for detecting local recurrence after radical prostatectomy or external beam radiation therapy. Because assessment on mp-MRI can be subjective, use of the newly developed standardized reporting Prostate Imaging and Reporting Archiving Data System (PI-RADS) scoring system and education of specialist radiologists are essential for accurate interpretation. This review focuses on the current place of mp-MRI in prostate cancer and its evolving role in the management of prostate cancer. PMID:26682144

  1. Ferritin reporter used for gene expression imaging by magnetic resonance

    SciTech Connect

    Ono, Kenji; Fuma, Kazuya; Tabata, Kaori; Sawada, Makoto

    2009-10-23

    Magnetic resonance imaging (MRI) is a minimally invasive way to provide high spatial resolution tomograms. However, MRI has been considered to be useless for gene expression imaging compared to optical imaging. In this study, we used a ferritin reporter, binding with biogenic iron, to make it a powerful tool for gene expression imaging in MRI studies. GL261 mouse glioma cells were over-expressed with dual-reporter ferritin-DsRed under {beta}-actin promoter, then gene expression was observed by optical imaging and MRI in a brain tumor model. GL261 cells expressing ferritin-DsRed fusion protein showed enhanced visualizing effect by reducing T2-weighted signal intensity for in vitro and in vivo MRI studies, as well as DsRed fluorescence for optical imaging. Furthermore, a higher contrast was achieved on T2-weighted images when permeating the plasma membrane of ferritin-DsRed-expressing GL261. Thus, a ferritin expression vector can be used as an MRI reporter to monitor in vivo gene expression.

  2. Evaluation of muscle injury using magnetic resonance imaging

    NASA Technical Reports Server (NTRS)

    LeBlanc, A. D.; Jaweed, M.; Evans, H.

    1993-01-01

    The objective of this study was to investigate spin echo T2 relaxation time changes in thigh muscles after intense eccentric exercise in healthy men. Spin echo and calculated T2 relaxation time images of the thighs were obtained on several occasions after exercise of one limb; the contralateral limb served as control. Muscle damage was verified by elevated levels of serum creatine kinase (CK). Thirty percent of the time no exercise effect was discernible on the magnetic resonance (MR) images. In all positive MR images (70%) the semitendinosus muscle was positive, while the biceps femoris, short head, and gracilis muscles were also positive in 50% and 25% of the total cases, respectively. The peak T2 relaxation time and serum CK were correlated (r = 0.94, p<0.01); temporal changes in muscle T2 relaxation time and serum CK were similar, although T2 relaxation time remained positive after serum CK returned to background levels. We conclude that magnetic resonance imaging can serve as a useful tool in the evaluation of eccentric exercise muscle damage by providing a quantitative indicator of damage and its resolution as well as the specific areas and muscles.

  3. Magnetic resonance microscopy of prostate tissue: How basic science can inform clinical imaging development

    SciTech Connect

    Bourne, Roger

    2013-03-15

    This commentary outlines how magnetic resonance imaging (MRI) microscopy studies of prostate tissue samples and whole organs have shed light on a number of clinical imaging mysteries and may enable more effective development of new clinical imaging methods.

  4. Magnetic resonance imaging of bone marrow disease in children

    SciTech Connect

    Cohen, M.D.; Klatte, E.C.; Baehner, R.; Smith, J.A.; Martin-Simmerman, P.; Carr, B.E.; Provisor, A.J.; Weetman, R.M.; Coates, T.; Siddiqui, A.

    1984-06-01

    Seven children underwent magnetic resonance imaging (MRI) of the bone marrow: results showed that it is technically feasible to obtain good MR images of marrow in children. MR has detected abnormality in the bone marrow of a child who had metastatic neuroblastoma. The extent of abnormality in the femur correlated well with findings of a bone marrow isotope scan. In one child who had idiopathic aplastic anemia, diseased marrow could not be distinguished from normal marrow on MR images. MRI identified abnormality of the marrow in osteogenic sarcoma, and demonstrated change in response to chemotherapy. It displayed marrow spread of tumors as well as CT. MRI showed marrow abnormality in four children who had leukemia.

  5. Advances in Surface Plasmon Resonance Imaging Enable Quantitative Tracking of Nanoscale Changes in Thickness and

    E-print Network

    Dutcher, John

    Advances in Surface Plasmon Resonance Imaging Enable Quantitative Tracking of Nanoscale Changes: To date, detailed studies of the thickness of coatings using surface plasmon resonance have been limited a significant improvement to surface plasmon resonance imaging (SPRi) that allows this sensitive technique

  6. Large Sample Group Independent Component Analysis of Functional Magnetic Resonance Imaging Using Anatomical

    E-print Network

    Yuille, Alan L.

    Large Sample Group Independent Component Analysis of Functional Magnetic Resonance Imaging Using of functional magnetic resonance imaging (fMRI) signals that is capable of revealing connected brain systems fMRI; group ICA; bagging; clustering; bootstrap I. INTRODUCTION Functional magnetic resonance

  7. Accelerating Magnetic Resonance Imaging by Unifying Sparse Models and Multiple Receivers

    E-print Network

    Goyal, Vivek K

    Accelerating Magnetic Resonance Imaging by Unifying Sparse Models and Multiple Receivers by Daniel Resonance Imaging by Unifying Sparse Models and Multiple Receivers by Daniel S. Weller Submitted of the requirements for the degree of Doctor of Philosophy in Electrical Engineering Abstract Magnetic resonance

  8. MULTI-PLANAR DYNAMIC MAGNETIC RESONANCE IMAGING: NEW TOOLS FOR SPEECH RESEARCH.

    E-print Network

    Jackson, Philip JB

    MULTI-PLANAR DYNAMIC MAGNETIC RESONANCE IMAGING: NEW TOOLS FOR SPEECH RESEARCH. Christine H. Shadle and usefulness of the technique. 1. INTRODUCTION Magnetic Resonance Imaging (MRI) has been used to good effect, University of Southampton, Southampton, SO17 1BJ UK. ABSTRACT A multiplanar Dynamic Magnetic Resonance

  9. Abstract-In this study, imaging of electrical current density in conducting objects, which contain nuclear magnetic resonance

    E-print Network

    Eyüboðlu, Murat

    nuclear magnetic resonance (NMR) active nuclei is planned using 0.15T Magnetic Resonance Imaging (MRI. Experiments performed on several phantoms and the results are presented. Keywords - Magnetic Resonance Imaging]. Nuclear magnetic resonance imaging techniques can be used to image the current density J . Joy et al. [6

  10. Noise reduction from magnetic resonance images using nonseperable transforms

    NASA Astrophysics Data System (ADS)

    Nezhadarya, Ehsan; Shamsollahi, Mohammad Bagher

    2006-03-01

    Multi-scale transforms have got a lot of applications in image processing, in recent years. Wavelet transform is a powerful multiscale transform for denoising noisy signals and images, but the usual two-dimensional separable wavelets are sub-optimal. These separable wavelet transforms can successfully identify zero dimensional singularities in images, but can weakly identify one dimensional singularities such as edges, curves and lines. In this sense, non-separable transforms such as Ridgelet and Curvelet transforms are proposed by Candes and Donoho. The coefficients produced by these non-separable transforms have shown to be sparser than wavelet coefficients. This fact results in better denoising capabilities than wavelet transform. These new non-separable transforms can identify direction in lines and curves, because of special structure of their basis elements. Basically, Magnetic Resonance images are probable to have Rician noise. In some special cases, this kind of noise can be supposed to be white Gaussian noise. In this paper, a new method for denoising MR images is proposed. This method is based on Monoscale Ridgelet transform. It is shown that this two transform can successfully denoise MR images embedded in white Gaussian noise. The results are better in comparison with usual wavelet denoising methods, based on both visual perception and signal-to-noise ratio.

  11. ADVANCED MAGNETIC RESONANCE IMAGING OF CEREBRAL CAVERNOUS MALFORMATIONS

    PubMed Central

    Shenkar, Robert; Venkatasubramanian, Palamadai N.; Wyrwicz, Alice M.; Zhao, Jin-cheng; Shi, Changbin; Akers, Amy; Marchuk, Douglas A.; Awad, Issam A.

    2008-01-01

    Objective We sought to assess the appearance of cerebral cavernous malformations (CCMs) on magnetic resonance (MR) imaging in murine Ccm1 and Ccm2 gene knockout models, and to develop a technique of lesion localization for correlative pathobiologic studies Methods Brains from eighteen CCM mutant mice (Ccm1+/-Trp53-/- and Ccm2+/-Trp53-/-) and 28 controls were imaged by gradient recalled echo (T2*)-weighted MR at 4.7 T and 14.1 T in vivo and/or ex vivo. After MR imaging, the brains were removed and stained with hematoxylin and eosin and cells were laser microdissected for molecular biologic studies. Results T2*-weighted MR imaging of brains in vivo and ex vivo revealed lesions similar to human CCMs in mutant mice, but not in control animals. Stereotactic localization and hematoxylin and eosin-staining of correlative tissue sections confirmed lesion histology, and revealed other areas of dilated capillaries in the same brains. Some lesions were identified by MR imaging at 14.1 T, but not at 4.7 T. PCR amplification from Ccm1 and ?-actin genes was demonstrated from nucleic acids extracted from laser microdissected lesional and perilesional cells. Conclusions The high field MR imaging techniques offer new opportunities for further investigation of disease pathogenesis in vivo, and the localization, staging and histobiologic dissection of lesions, including the presumed earliest stages of CCM lesion development. PMID:18981891

  12. Magnetic resonance imaging and contrast enhancement. Scientific report

    SciTech Connect

    Swenberg, C.E.; Movius, E.G.

    1988-01-01

    Chapters II through VI of this report discuss: Relaxation of Nuclear Spins; Echo Techniques; Basic Imaging Pulse Sequences; Partial Saturation Recovery; Inversion Recovery; Spin Echo; Effects of Pulse Sequence on Image Contrast; Contrast Agents; Theoretical Aspects; Pharmacokinetics and Toxicity; and Physiological Rationale for Agent Selection. One of the major goals in all medical imaging techniques is to maximize one's ability to visualize and differentiate adjacent tissue regions in the body on the basis of differences in anatomy, physiology, or various pathological processes. Magnetic resonance (MR) imaging offers distinct advantages over conventional x-ray imaging because of the possibility of selecting specific pulse sequences that can differentiate adjacent structures on the basis of differences in proton density, T/sub 1/ or T/sub 2/ relaxation rates, or flow. As a result of applying these various pulse sequences, numerous images have been obtained of the brain and other organs that demonstrate considerably more-detailed anatomical structure than had previously been available with computerized tomography, ultrasound, or nuclear medicine techniques. In some situations it is clearly superior, such as in the diagnosis of multiple sclerosis.

  13. Focal liver lesions: Practical magnetic resonance imaging approach

    PubMed Central

    Matos, António P; Velloni, Fernanda; Ramalho, Miguel; AlObaidy, Mamdoh; Rajapaksha, Aruna; Semelka, Richard C

    2015-01-01

    With the widespread of cross-sectional imaging, a growth of incidentally detected focal liver lesions (FLL) has been observed. A reliable detection and characterization of FLL is critical for optimal patient management. Maximizing accuracy of imaging in the context of FLL is paramount in avoiding unnecessary biopsies, which may result in post-procedural complications. A tremendous development of new imaging techniques has taken place during these last years. Nowadays, Magnetic resonance imaging (MRI) plays a key role in management of liver lesions, using a radiation-free technique and a safe contrast agent profile. MRI plays a key role in the non-invasive correct characterization of FLL. MRI is capable of providing comprehensive and highly accurate diagnostic information, with the additional advantage of lack of harmful ionizing radiation. These properties make MRI the mainstay for the noninvasive evaluation of focal liver lesions. In this paper we review the state-of-the-art MRI liver protocol, briefly discussing different sequence types, the unique characteristics of imaging non-cooperative patients and discuss the role of hepatocyte-specific contrast agents. A review of the imaging features of the most common benign and malignant FLL is presented, supplemented by a schematic representation of a simplistic practical approach on MRI. PMID:26261689

  14. PHYS 460 ADVANCED TOPICS IN MAGNETIC RESONANCE IMAGING Syllabus: The second semester for the imaging track addresses advanced topics such

    E-print Network

    Akerib, Daniel S.

    PHYS 460 ­ ADVANCED TOPICS IN MAGNETIC RESONANCE IMAGING Syllabus: The second semester for the imaging track addresses advanced topics such as electromagnetic coil and hardware design, parallel imaging, spectroscopy topics, sequence design and debugging, artifacts, fast imaging, diffusion imaging, blood flow

  15. High pressure magnetic resonance imaging with metallic vessels.

    PubMed

    Han, Hui; Ouellette, Matthew; MacMillan, Bryce; Goora, Frederic; MacGregor, Rodney; Green, Derrick; Balcom, Bruce J

    2011-12-01

    High pressure measurements in most scientific fields rely on metal vessels given the superior tensile strength of metals. We introduce high pressure magnetic resonance imaging (MRI) measurements with metallic vessels. The developed MRI compatible metallic pressure vessel concept is very general in application. Macroscopic physical systems are now amenable to spatially resolved nuclear magnetic resonance (NMR) study at variable pressure and temperature. Metallic pressure vessels not only provide inherently high tensile strengths and efficient temperature control, they also permit optimization of the MRI RF probe sensitivity. An MRI compatible pressure vessel is demonstrated with a rock core holder fabricated using non-magnetic stainless steel. Water flooding through a porous rock under pressure is shown as an example of its applications. High pressure NMR spectroscopy plays an indispensable role in several science fields. This work will open new vistas of study for high pressure material science MRI and MR. PMID:21962929

  16. High pressure magnetic resonance imaging with metallic vessels

    NASA Astrophysics Data System (ADS)

    Han, Hui; Ouellette, Matthew; MacMillan, Bryce; Goora, Frederic; MacGregor, Rodney; Green, Derrick; Balcom, Bruce J.

    2011-12-01

    High pressure measurements in most scientific fields rely on metal vessels given the superior tensile strength of metals. We introduce high pressure magnetic resonance imaging (MRI) measurements with metallic vessels. The developed MRI compatible metallic pressure vessel concept is very general in application. Macroscopic physical systems are now amenable to spatially resolved nuclear magnetic resonance (NMR) study at variable pressure and temperature. Metallic pressure vessels not only provide inherently high tensile strengths and efficient temperature control, they also permit optimization of the MRI RF probe sensitivity. An MRI compatible pressure vessel is demonstrated with a rock core holder fabricated using non-magnetic stainless steel. Water flooding through a porous rock under pressure is shown as an example of its applications. High pressure NMR spectroscopy plays an indispensable role in several science fields. This work will open new vistas of study for high pressure material science MRI and MR.

  17. Magnetic resonance imaging and electromyography as indexes of muscle function

    NASA Technical Reports Server (NTRS)

    Adams, Gregory R.; Duvoisin, Marc R.; Dudley, Gary A.

    1992-01-01

    A hypothesis is tested that exercise-induced magnetic resonance (MR) contrast shifts would relate to electromyography (EMG) amplitude if both measures reflect muscle use during exercise. Both magnetic resonance images (MRI) and EMG data were obtained for separate eccentric (ECC) and cocentric (CON) exercise of increasing intensity for seven subjects 30-32 yr old. CON and ECC actions caused increased integrated EMG (IEMG) and T2 values which were strongly related with relative resistance. The rate of increase and absolute value of both T2 and IEMG were found to be greater for CON than for ECC actions. For both actions IEMG and T2 were correlated. Data obtained suggest that surface IEMG accurately reflects the contractile behavior of muscle and exercise-induced increases in MRI T2 values reflect certain processes that scale with muscle use.

  18. Imaging atoms from resonance fluorescence spectrum beyond the diffraction limit

    NASA Astrophysics Data System (ADS)

    Liao, Zeyang; Al-Amri, Mohammad; Zubairy, M. Suhail

    2014-03-01

    We calculate the resonance fluorescence spectrum of a linear chain of two-level atoms driven by a gradient coherent laser field. The result shows that we can determine the positions of atoms from the spectrum even when the atoms locate within subwavelength range and the dipole-dipole interaction is significant. This far-field resonance fluorescence localization microscopy method does not require point-by-point scanning and it may be more time-efficient. We also give a possible scheme to extract the position information in an extended region without requiring more peak power of laser. We also briefly discuss how to do a 2D imaging based on our scheme. This work is supported by grants from the King Abdulaziz City for Science and Technology (KACST) and the Qatar National Research Fund (QNRF) under the NPRP project.

  19. Magnetic resonance imaging and spectroscopy of the murine cardiovascular system

    PubMed Central

    Akki, Ashwin; Gupta, Ashish

    2013-01-01

    Magnetic resonance imaging (MRI) has emerged as a powerful and reliable tool to noninvasively study the cardiovascular system in clinical practice. Because transgenic mouse models have assumed a critical role in cardiovascular research, technological advances in MRI have been extended to mice over the last decade. These have provided critical insights into cardiac and vascular morphology, function, and physiology/pathophysiology in many murine models of heart disease. Furthermore, magnetic resonance spectroscopy (MRS) has allowed the nondestructive study of myocardial metabolism in both isolated hearts and in intact mice. This article reviews the current techniques and important pathophysiological insights from the application of MRI/MRS technology to murine models of cardiovascular disease. PMID:23292717

  20. Innovative computing for diagnoses from medical, magnetic-resonance imaging

    SciTech Connect

    Diegert, C.

    1997-01-01

    The author presents a final report on a Laboratory-Directed Research and Development (LDRD) project, Innovative Computing for Diagnoses from Medical, Magnetic-Resonance Imaging, performed during fiscal years 1992 and 1993. The project defined a role for high-performance computing in surgery: the supercomputer can automatically summarize the three-dimensional extents of lesions and other clinically-relevant structures, and can deliver these summaries to workstation-based, augmented-reality environments at the clinical site. The author developed methods and software to make these summaries from the digital data already acquired using clinical, magnetic-resonance machines. In joint work with Albuquerque`s Department of Veterans Affairs Hospital, the author applied this work, and obtained a basis for planning, for rehearsal, and for guidance during surgery.

  1. Pattern recognition of magnetic resonance images with application to atherosclerosis

    SciTech Connect

    Carman, C.S.

    1989-01-01

    Magnetic resonance imaging provides excellent soft tissue contrast enabling the non-invasive visualization of soft tissue diseases. The quantification of tissues visible in MR images would significantly increase the diagnostic information available. While tissue selection methods exist for CT images, those same methods do not work with MR images. This dissertation focuses on the application of image processing and pattern recognition techniques to MR images for the identification and quantification of soft tissues, atherosclerosis in particular. Atherosclerosis is a chronic disease of human arteries responsible for significant mortality and medical expense. Current diagnostic methods are invasive and carry significant risk. Supervised pattern recognition methods were investigated for tissue identification in MR images. The classifiers were trained A Fisher linear classifier successfully identified the tissues of interest from MR images of excised arteries, performing better than a minimum distance to the means classifier. Quantitative measures of the disease state were computed from the results and 3-D displays were generated of the diseased anatomy. For tissue in vivo, adequate histology can be difficult to collect, increasing the difficulty of training the classifiers and making the results less accurate. Cluster analysis was used in this dissertation to generate the training information. A new cluster analysis method was developed. ISODATA was modified to use hierarchical stopping rules. The new method was tested in a Monte Carlo study and with real world data sets. Comparisons were made with published methods using the same data. An information theoretic criterion, the CAIC, was found to be an excellent criteria for hierarchical stopping rules.

  2. Magnetic resonance imaging by using nano-magnetic particles

    NASA Astrophysics Data System (ADS)

    Shokrollahi, H.; Khorramdin, A.; Isapour, Gh.

    2014-11-01

    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.

  3. Magnetic Resonance Imaging of Complications of Anterior Cruciate Ligament Reconstruction.

    PubMed

    Dayan, Etan; Maderazo, Alex; Fitzpatrick, Darren

    2015-12-01

    The incidence of anterior cruciate ligament reconstruction (ACL-R) has increased in recent years. ACL-R plays an important role in the prevention of secondary osteoarthritis from resultant joint instability. Magnetic resonance imaging is the preferred modality in the evaluation of ACL-R complications. Complications after ACL-R may be broadly characterized as those resulting in decreased range of motion (arthrofibrosis, impingement) and resulting in increased laxity (graft disruption). Other miscellaneous complications that do not fall into these categories will also be discussed in this article. PMID:26665245

  4. Quantification of Liver Fat with Magnetic Resonance Imaging

    PubMed Central

    Reeder, Scott B.; Sirlin, Claude

    2010-01-01

    Intracellular fat accumulation is common feature of liver disease. Intracellular fat (steatosis) is the histological hallmark of non-alcoholic fatty liver disease (NAFLD) but also may occur with alcohol abuse, viral hepatitis, HIV and genetic lipodystrophies, and chemotherapy. This article reviews emerging magnetic resonance imaging techniques that attempt to quantify liver fat. The content provides an overview of fatty liver disease and diseases where fat is an important disease feature. Also discussed is the current use and limitation of non-targeted biopsy in diffuse liver disease, and why quantitative non-invasive biomarkers of liver fat would be beneficial. PMID:21094444

  5. Use of Magnetic Resonance Imaging to Monitor Iron Overload

    PubMed Central

    Wood, John C.

    2014-01-01

    SYNOPSIS Treatment of iron overload requires robust estimates of total body iron burden and its response to iron chelation therapy. Compliance with chelation therapy varies considerably among patients and individual reporting is notoriously unreliable. Even with perfect compliance, intersubject variability in chelator effectiveness is extremely high, necessitating reliable iron estimates to guide dose titration. In addition, each chelator has a unique profile with respect to clearing iron stores from different organs. This chapter will present the tools available to clinicians monitoring their patients, focusing on non-invasive magnetic resonance imaging methods because they have become the de-facto standard of care. PMID:25064711

  6. Use of magnetic resonance imaging to monitor iron overload.

    PubMed

    Wood, John C

    2014-08-01

    Treatment of iron overload requires robust estimates of total-body iron burden and its response to iron chelation therapy. Compliance with chelation therapy varies considerably among patients, and individual reporting is notoriously unreliable. Even with perfect compliance, intersubject variability in chelator effectiveness is extremely high, necessitating reliable iron estimates to guide dose titration. In addition, each chelator has a unique profile with respect to clearing iron stores from different organs. This article presents the tools available to clinicians to monitor their patients, focusing on noninvasive magnetic resonance imaging methods because they have become the de facto standard of care. PMID:25064711

  7. Magnetic Resonance Imaging of the Lung as an Alternative for a Pregnant Woman with Pulmonary Tuberculosis

    PubMed Central

    Schloß, Manuel; Heckrodt, Jan; Schneider, Christian; Discher, Thomas; Krombach, Gabriele Anja

    2015-01-01

    We report a case of a pregnant 21-year-old woman with pulmonary tuberculosis in which magnetic resonance imaging of the lung was used to assess the extent and characteristics of the pathological changes. Although the lung has been mostly ignored in magnetic resonance imaging for many decades, today technical development enables detailed examinations of the lung. The technique is now entering the clinical arena and its indications are increasing. Magnetic resonance imaging of the lung is not only an alternative method without radiation exposure, it can provide additional information in pulmonary imaging compared to other modalities including computed tomography. We describe a successful application of magnetic resonance imaging of the lung and the imaging appearance of post-primary tuberculosis. This case report indicates that magnetic resonance imaging of the lung can potentially be the first choice imaging technique in pregnant women with suspected pulmonary tuberculosis. PMID:26622928

  8. Quantitative Magnetic Resonance Imaging of 3-He Gas Transport

    NASA Astrophysics Data System (ADS)

    Jacob, Richard E.; Minard, Kevin R.

    2007-03-01

    In magnetic resonance (MR) imaging the use of laser-polarized 3-He dramatically increases detection sensitivity and facilitates gas visualization. Here, the potential use of 3-He MR imaging for quantifying gas transport in the respiratory tract of laboratory rodents is examined by studying laminar flow in a straight pipe with a diameter comparable to the rat trachea (˜ 3.2 mm). At physiological flow rates (˜ 4 ml/s), laminar-like features are observed in 2D images of axial diffusion, and the structure of observed flow lamina differs significantly from predictions based on the Navier-Stokes equations. To reconcile these results, we formulate a statistical model of gas transport that accounts for Brownian motion on the imaging time scale. The model uses the 2D solution to the diffusion equation to describe how diffusing gas molecules sample the stationary flow field. The effects on MR measurements are then formulated in terms of the mean flow velocity, higher order correlation functions, and the details of data acquisition. Comparison between modeling and experiment shows that MR imaging results are accurately predicted for different gas mixtures and acquisition conditions. The model is generally applicable to any flow conduit, resulting in a quantitative basis for noninvasive gas transport studies.

  9. Molecular Magnetic Resonance Imaging of Tumor Response to Therapy

    PubMed Central

    Shuhendler, Adam J.; Ye, Deju; Brewer, Kimberly D.; Bazalova-Carter, Magdalena; Lee, Kyung-Hyun; Kempen, Paul; Dane Wittrup, K.; Graves, Edward E.; Rutt, Brian; Rao, Jianghong

    2015-01-01

    Personalized cancer medicine requires measurement of therapeutic efficacy as early as possible, which is optimally achieved by three-dimensional imaging given the heterogeneity of cancer. Magnetic resonance imaging (MRI) can obtain images of both anatomy and cellular responses, if acquired with a molecular imaging contrast agent. The poor sensitivity of MRI has limited the development of activatable molecular MR contrast agents. To overcome this limitation of molecular MRI, a novel implementation of our caspase-3-sensitive nanoaggregation MRI (C-SNAM) contrast agent is reported. C-SNAM is triggered to self-assemble into nanoparticles in apoptotic tumor cells, and effectively amplifies molecular level changes through nanoaggregation, enhancing tissue retention and spin-lattice relaxivity. At one-tenth the current clinical dose of contrast agent, and following a single imaging session, C-SNAM MRI accurately measured the response of tumors to either metronomic chemotherapy or radiation therapy, where the degree of signal enhancement is prognostic of long-term therapeutic efficacy. Importantly, C-SNAM is inert to immune activation, permitting radiation therapy monitoring. PMID:26440059

  10. Magnetic resonance imaging of convection in laser-polarized xenon R. W. Mair,1

    E-print Network

    Walsworth, Ronald L.

    Magnetic resonance imaging of convection in laser-polarized xenon R. W. Mair,1 C.-H. Tseng,1,2 G. P, Massachusetts 02139 Received 7 October 1999 We demonstrate nuclear magnetic resonance NMR imaging of the flow in this paper nuclear magnetic reso- nance NMR imaging of both gas diffusion and convective flow in a closed two

  11. Successful serial imaging of the mouse cerebral arteries using conventional 3-T magnetic resonance imaging.

    PubMed

    Makino, Hiroshi; Hokamura, Kazuya; Natsume, Takahiro; Kimura, Tetsuro; Kamio, Yoshinobu; Magata, Yasuhiro; Namba, Hiroki; Katoh, Takasumi; Sato, Shigehito; Hashimoto, Tomoki; Umemura, Kazuo

    2015-09-01

    Serial imaging studies can be useful in characterizing the pathologic and physiologic remodeling of cerebral arteries in various mouse models. We tested the feasibility of using a readily available, conventional 3-T magnetic resonance imaging (MRI) to serially image cerebrovascular remodeling in mice. We utilized a mouse model of intracranial aneurysm as a mouse model of the dynamic, pathologic remodeling of cerebral arteries. Aneurysms were induced by hypertension and a single elastase injection into the cerebrospinal fluid. For the mouse cerebrovascular imaging, we used a conventional 3-T MRI system and a 40-mm saddle coil. We used non-enhanced magnetic resonance angiography (MRA) to detect intracranial aneurysm formation and T2-weighted imaging to detect aneurysmal subarachnoid hemorrhage. A serial MRI was conducted every 2 to 3 days. MRI detection of aneurysm formation and subarachnoid hemorrhage was compared against the postmortem inspection of the brain that was perfused with dye. The imaging times for the MRA and T2-weighted imaging were 3.7±0.5 minutes and 4.8±0.0 minutes, respectively. All aneurysms and subarachnoid hemorrhages were correctly identified by two masked observers on MRI. This MRI-based serial imaging technique was useful in detecting intracranial aneurysm formation and subarachnoid hemorrhage in mice. PMID:25920958

  12. Imaging of Anal Fistulas: Comparison of Computed Tomographic Fistulography and Magnetic Resonance Imaging

    PubMed Central

    Liang, Changhu; Zhao, Bin; Du, Yinglin; Wang, Cuiyan; Jiang, Wanli

    2014-01-01

    The primary importance of magnetic resonance (MR) imaging in evaluating anal fistulas lies in its ability to demonstrate hidden areas of sepsis and secondary extensions in patients with fistula in ano. MR imaging is relatively expensive, so there are many healthcare systems worldwide where access to MR imaging remains restricted. Until recently, computed tomography (CT) has played a limited role in imaging fistula in ano, largely owing to its poor resolution of soft tissue. In this article, the different imaging features of the CT and MRI are compared to demonstrate the relative accuracy of CT fistulography for the preoperative assessment of fistula in ano. CT fistulography and MR imaging have their own advantages for preoperative evaluation of perianal fistula, and can be applied to complement one another when necessary. PMID:25469082

  13. Magnetic Resonance Imaging (MRI) Meshaal Al Yahya, Student, 200426900, Dept. of EE, KFUPM, Dhahran 31261, Saudi Arabia

    E-print Network

    Masoudi, Husain M.

    1 Magnetic Resonance Imaging (MRI) Meshaal Al Yahya, Student, 200426900, Dept. of EE, KFUPM, Dhahran 31261, Saudi Arabia Abstract-- Magnetic Resonance Imaging (MRI) is basically a medical imaging me to pick this topic. II. WHAT IS MRI? Magnetic Resonance Imaging (MRI) is an imaging tech- nique

  14. Magnetic resonance imaging of the pericardium: normal and pathologic findings

    SciTech Connect

    Stark, D.D.; Higgins, C.B.; Lanzer, P.; Lipton, M.J.; Schiller, N.; Crooks, L.E.; Botvinick, E.B.; Kaufman, L.

    1984-02-01

    Twenty normal subjects and ten patients with pericardial abnormalities underwent ECG-gated magnetic resonance (MR) imaging of the thorax using a 0.35-tesla superconducting system. The patients with pericardial abnormalities were also evaluated with serial chest radiography, ultrasound, computed tomography, and/or angiography. ECG gating was necessary to identify the normal pericardium, which was visualized as a 1- to 2-mm-wide curvilinear structure of low signal intensity. Pericardial thickening in constrictive pericarditis was clearly delineated on gated MR images. Pericardial inflammation caused a marked increase in signal intensity as well as thickening of the pericardium. Pericardial effusions and pericardial adhesions were also demonstrated. A simple pericardial cyst and a complex pericardial mass were identified and differentiated from pericardial fat and diaphragmatic eventration. MR appears to be an important modality for the evaluation of pericardial disease.

  15. Utility of magnetic resonance spectroscopic imaging for human epilepsy

    PubMed Central

    Kuzniecky, Ruben I.

    2015-01-01

    This review discusses the potential utility of broad based use of magnetic resonance (MR) spectroscopic imaging for human epilepsy and seizure localization. The clinical challenges are well known to the epilepsy community, intrinsic in the variability of location, volumetric size and network extent of epileptogenic tissue in individual patients. The technical challenges are also evident, with high performance requirements in multiple steps, including magnet homogeneity, detector performance, sequence design, speed of acquisition in addition to large territory spectral processing. We consider how MR spectroscopy and spectroscopic imaging has been informative for epilepsy thus far, with specific attention to what is measured, the interpretation of such measurements and technical performance challenges. Examples are shown from medial temporal lobe and neocortical epilepsies are considered from 4T, 7T and most recently 3T. PMID:25853088

  16. Applications of Manganese-Enhanced Magnetic Resonance Imaging in Neuroscience

    NASA Astrophysics Data System (ADS)

    McCreary, J. Keiko

    Manganese-Enhanced Magnetic Resonance Imaging (MEMRI) has proven itself to be a beneficial technique in the field of Neuroscience. This thesis applies MEMRI to studies in neuroscience by first establishing the limitations concerning the use of MEMRI in live rats. Experiment 1 used an osmotic pump for manganese (Mn) delivery to the lateral ventricles for acquisition of anatomical images using MEMRI. From my knowledge, this was the first method demonstrating slow infusion of Mn to the lateral ventricles. In Experiment 2, MEMRI was used for volumetric analysis the whole brain and hippocampus of prenatally stressed rats. To my knowledge, this study was the first to investigate the effect of generational prenatal stress on the structure of a rat's brain using MEMRI and histology. Additionally, Experiment 2 investigated the use of a subcutaneous osmotic pump to deliver Mn for MEMRI. A summary on the use of MEMRI in Neuroscience concludes this thesis, with a discussion on the methods used and related technical considerations.

  17. Simultaneous Magnetic Resonance Imaging and Consolidation Measurement of Articular Cartilage

    PubMed Central

    Wellard, Robert Mark; Ravasio, Jean-Philippe; Guesne, Samuel; Bell, Christopher; Oloyede, Adekunle; Tevelen, Greg; Pope, James M.; Momot, Konstantin I.

    2014-01-01

    Magnetic resonance imaging (MRI) offers the opportunity to study biological tissues and processes in a non-disruptive manner. The technique shows promise for the study of the load-bearing performance (consolidation) of articular cartilage and changes in articular cartilage accompanying osteoarthritis. Consolidation of articular cartilage involves the recording of two transient characteristics: the change over time of strain and the hydrostatic excess pore pressure (HEPP). MRI study of cartilage consolidation under mechanical load is limited by difficulties in measuring the HEPP in the presence of the strong magnetic fields associated with the MRI technique. Here we describe the use of MRI to image and characterize bovine articular cartilage deforming under load in an MRI compatible consolidometer while monitoring pressure with a Fabry-Perot interferometer-based fiber-optic pressure transducer. PMID:24803188

  18. Narrow band deformable registration of prostate magnetic resonance imaging, magnetic resonance spectroscopic imaging, and computed tomography studies

    SciTech Connect

    Schreibmann, Eduard; Xing Lei . E-mail: lei@reyes.stanford.edu

    2005-06-01

    Purpose: Endorectal (ER) coil-based magnetic resonance imaging (MRI) and magnetic resonance spectroscopic imaging (MRSI) is often used to obtain anatomic and metabolic images of the prostate and to accurately identify and assess the intraprostatic lesions. Recent advancements in high-field (3 Tesla or above) MR techniques affords significantly enhanced signal-to-noise ratio and makes it possible to obtain high-quality MRI data. In reality, the use of rigid or inflatable endorectal probes deforms the shape of the prostate gland, and the images so obtained are not directly usable in radiation therapy planning. The purpose of this work is to apply a narrow band deformable registration model to faithfully map the acquired information from the ER-based MRI/MRSI onto treatment planning computed tomography (CT) images. Methods and Materials: A narrow band registration, which is a hybrid method combining the advantages of pixel-based and distance-based registration techniques, was used to directly register ER-based MRI/MRSI with CT. The normalized correlation between the two input images for registration was used as the metric, and the calculation was restricted to those points contained in the narrow bands around the user-delineated structures. The narrow band method is inherently efficient because of the use of a priori information of the meaningful contour data. The registration was performed in two steps. First, the two input images were grossly aligned using a rigid registration. The detailed mapping was then modeled by free form deformations based on B-spline. The limited memory Broyden-Fletcher-Goldfarb-Shanno algorithm (L-BFGS), which is known for its superior performance in dealing with high-dimensionality problems, was implemented to optimize the metric function. The convergence behavior of the algorithm was studied by self-registering an MR image with 100 randomly initiated relative positions. To evaluate the performance of the algorithm, an MR image was intentionally distorted, and an attempt was then made to register the distorted image with the original one. The ability of the algorithm to recover the original image was assessed using a checkerboard graph. The mapping of ER-based MRI onto treatment planning CT images was carried out for two clinical cases, and the performance of the registration was evaluated. Results: A narrow band deformable image registration algorithm has been implemented for direct registration of ER-based prostate MRI/MRSI and CT studies. The convergence of the algorithm was confirmed by starting the registration experiment from more than 100 different initial conditions. It was shown that the technique can restore an MR image from intentionally introduced deformations with an accuracy of approximately 2 mm. Application of the technique to two clinical prostate MRI/CT registrations indicated that it is capable of producing clinically sensible mapping. The whole registration procedure for a complete three-dimensional study (containing 256 x 256 x 64 voxels) took less than 15 min on a standard personal computer, and the convergence was usually achieved in fewer than 100 iterations. Conclusions: A deformable image registration procedure suitable for mapping ER-based MRI data onto planning CT images was presented. Both hypothetical tests and patient studies have indicated that the registration is reliable and provides a valuable tool to integrate the ER-based MRI/MRSI information to guide prostate radiation therapy treatment.

  19. Magnetic Resonance Imaging of Human Tissue-Engineered Adipose Substitutes.

    PubMed

    Proulx, Maryse; Aubin, Kim; Lagueux, Jean; Audet, Pierre; Auger, Michèle; Fortin, Marc-André; Fradette, Julie

    2015-07-01

    Adipose tissue (AT) substitutes are being developed to answer the strong demand in reconstructive surgery. To facilitate the validation of their functional performance in vivo, and to avoid resorting to excessive number of animals, it is crucial at this stage to develop biomedical imaging methodologies, enabling the follow-up of reconstructed AT substitutes. Until now, biomedical imaging of AT substitutes has scarcely been reported in the literature. Therefore, the optimal parameters enabling good resolution, appropriate contrast, and graft delineation, as well as blood perfusion validation, must be studied and reported. In this study, human adipose substitutes produced from adipose-derived stem/stromal cells using the self-assembly approach of tissue engineering were implanted into athymic mice. The fate of the reconstructed AT substitutes implanted in vivo was successfully followed by magnetic resonance imaging (MRI), which is the imaging modality of choice for visualizing soft ATs. T1-weighted images allowed clear delineation of the grafts, followed by volume integration. The magnetic resonance (MR) signal of reconstructed AT was studied in vitro by proton nuclear magnetic resonance ((1)H-NMR). This confirmed the presence of a strong triglyceride peak of short longitudinal proton relaxation time (T1) values (200 ± 53 ms) in reconstructed AT substitutes (total T1=813 ± 76 ms), which establishes a clear signal difference between adjacent muscle, connective tissue, and native fat (total T1 ~300 ms). Graft volume retention was followed up to 6 weeks after implantation, revealing a gradual resorption rate averaging at 44% of initial substitute's volume. In addition, vascular perfusion measured by dynamic contrast-enhanced-MRI confirmed the graft's vascularization postimplantation (14 and 21 days after grafting). Histological analysis of the grafted tissues revealed the persistence of numerous adipocytes without evidence of cysts or tissue necrosis. This study describes the in vivo grafting of human adipose substitutes devoid of exogenous matrix components, and for the first time, the optimal parameters necessary to achieve efficient MRI visualization of grafted tissue-engineered adipose substitutes. PMID:25549069

  20. Diffusion weighted magnetic resonance imaging and its recent trend—a survey

    PubMed Central

    Chilla, Geetha Soujanya; Tan, Cher Heng

    2015-01-01

    Since its inception in 1985, diffusion weighted magnetic resonance imaging has been evolving and is becoming instrumental in diagnosis and investigation of tissue functions in various organs including brain, cartilage, and liver. Even though brain related pathology and/or investigation remains as the main application, diffusion weighted magnetic resonance imaging (DWI) is becoming a standard in oncology and in several other applications. This review article provides a brief introduction of diffusion weighted magnetic resonance imaging, challenges involved and recent advancements. PMID:26029644

  1. The physics of functional magnetic resonance imaging (fMRI)

    NASA Astrophysics Data System (ADS)

    Buxton, Richard B.

    2013-09-01

    Functional magnetic resonance imaging (fMRI) is a methodology for detecting dynamic patterns of activity in the working human brain. Although the initial discoveries that led to fMRI are only about 20 years old, this new field has revolutionized the study of brain function. The ability to detect changes in brain activity has a biophysical basis in the magnetic properties of deoxyhemoglobin, and a physiological basis in the way blood flow increases more than oxygen metabolism when local neural activity increases. These effects translate to a subtle increase in the local magnetic resonance signal, the blood oxygenation level dependent (BOLD) effect, when neural activity increases. With current techniques, this pattern of activation can be measured with resolution approaching 1 mm3 spatially and 1 s temporally. This review focuses on the physical basis of the BOLD effect, the imaging methods used to measure it, the possible origins of the physiological effects that produce a mismatch of blood flow and oxygen metabolism during neural activation, and the mathematical models that have been developed to understand the measured signals. An overarching theme is the growing field of quantitative fMRI, in which other MRI methods are combined with BOLD methods and analyzed within a theoretical modeling framework to derive quantitative estimates of oxygen metabolism and other physiological variables. That goal is the current challenge for fMRI: to move fMRI from a mapping tool to a quantitative probe of brain physiology.

  2. The physics of functional magnetic resonance imaging (fMRI)

    PubMed Central

    Buxton, Richard B

    2015-01-01

    Functional magnetic resonance imaging (fMRI) is a methodology for detecting dynamic patterns of activity in the working human brain. Although the initial discoveries that led to fMRI are only about 20 years old, this new field has revolutionized the study of brain function. The ability to detect changes in brain activity has a biophysical basis in the magnetic properties of deoxyhemoglobin, and a physiological basis in the way blood flow increases more than oxygen metabolism when local neural activity increases. These effects translate to a subtle increase in the local magnetic resonance signal, the blood oxygenation level dependent (BOLD) effect, when neural activity increases. With current techniques, this pattern of activation can be measured with resolution approaching 1 mm3 spatially and 1 s temporally. This review focuses on the physical basis of the BOLD effect, the imaging methods used to measure it, the possible origins of the physiological effects that produce a mismatch of blood flow and oxygen metabolism during neural activation, and the mathematical models that have been developed to understand the measured signals. An overarching theme is the growing field of quantitative fMRI, in which other MRI methods are combined with BOLD methods and analyzed within a theoretical modeling framework to derive quantitative estimates of oxygen metabolism and other physiological variables. That goal is the current challenge for fMRI: to move fMRI from a mapping tool to a quantitative probe of brain physiology. PMID:24006360

  3. Radiation-induced optic neuropathy: A magnetic resonance imaging study

    SciTech Connect

    Guy, J.; Mancuso, A.; Beck, R.; Moster, M.L.; Sedwick, L.A.; Quisling, R.G.; Rhoton, A.L. Jr.; Protzko, E.E.; Schiffman, J. )

    1991-03-01

    Optic neuropathy induced by radiation is an infrequent cause of delayed visual loss that may at times be difficult to differentiate from compression of the visual pathways by recurrent neoplasm. The authors describe six patients with this disorder who experienced loss of vision 6 to 36 months after neurological surgery and radiation therapy. Of the six patients in the series, two had a pituitary adenoma and one each had a metastatic melanoma, multiple myeloma, craniopharyngioma, and lymphoepithelioma. Visual acuity in the affected eyes ranged from 20/25 to no light perception. Magnetic resonance (MR) imaging showed sellar and parasellar recurrence of both pituitary adenomas, but the intrinsic lesions of the optic nerves and optic chiasm induced by radiation were enhanced after gadolinium-diethylenetriaminepenta-acetic acid (DTPA) administration and were clearly distinguishable from the suprasellar compression of tumor. Repeated MR imaging showed spontaneous resolution of gadolinium-DTPA enhancement of the optic nerve in a patient who was initially suspected of harboring recurrence of a metastatic malignant melanoma as the cause of visual loss. The authors found the presumptive diagnosis of radiation-induced optic neuropathy facilitated by MR imaging with gadolinium-DTPA. This neuro-imaging procedure may help avert exploratory surgery in some patients with recurrent neoplasm in whom the etiology of visual loss is uncertain.

  4. jSIPRO - analysis tool for magnetic resonance spectroscopic imaging.

    PubMed

    Jiru, Filip; Skoch, Antonin; Wagnerova, Dita; Dezortova, Monika; Hajek, Milan

    2013-10-01

    Magnetic resonance spectroscopic imaging (MRSI) involves a huge number of spectra to be processed and analyzed. Several tools enabling MRSI data processing have been developed and widely used. However, the processing programs primarily focus on sophisticated spectra processing and offer limited support for the analysis of the calculated spectroscopic maps. In this paper the jSIPRO (java Spectroscopic Imaging PROcessing) program is presented, which is a java-based graphical interface enabling post-processing, viewing, analysis and result reporting of MRSI data. Interactive graphical processing as well as protocol controlled batch processing are available in jSIPRO. jSIPRO does not contain a built-in fitting program. Instead, it makes use of fitting programs from third parties and manages the data flows. Currently, automatic spectra processing using LCModel, TARQUIN and jMRUI programs are supported. Concentration and error values, fitted spectra, metabolite images and various parametric maps can be viewed for each calculated dataset. Metabolite images can be exported in the DICOM format either for archiving purposes or for the use in neurosurgery navigation systems. PMID:23870172

  5. Active resonant subwavelength grating for scannerless range imaging sensors.

    SciTech Connect

    Kemme, Shanalyn A.; Nellums, Robert O.; Boye, Robert R.; Peters, David William

    2006-11-01

    In this late-start LDRD, we will present a design for a wavelength-agile, high-speed modulator that enables a long-term vision for the THz Scannerless Range Imaging (SRI) sensor. It takes the place of the currently-utilized SRI micro-channel plate which is limited to photocathode sensitive wavelengths (primarily in the visible and near-IR regimes). Two of Sandia's successful technologies--subwavelength diffractive optics and THz sources and detectors--are poised to extend the capabilities of the SRI sensor. The goal is to drastically broaden the SRI's sensing waveband--all the way to the THz regime--so the sensor can see through image-obscuring, scattering environments like smoke and dust. Surface properties, such as reflectivity, emissivity, and scattering roughness, vary greatly with the illuminating wavelength. Thus, objects that are difficult to image at the SRI sensor's present near-IR wavelengths may be imaged more easily at the considerably longer THz wavelengths (0.1 to 1mm). The proposed component is an active Resonant Subwavelength Grating (RSG). Sandia invested considerable effort on a passive RSG two years ago, which resulted in a highly-efficient (reflectivity greater than gold), wavelength-specific reflector. For this late-start LDRD proposal, we will transform the passive RSG design into an active laser-line reflector.

  6. Grid Computing Application for Brain Magnetic Resonance Image Processing

    NASA Astrophysics Data System (ADS)

    Valdivia, F.; Crépeault, B.; Duchesne, S.

    2012-02-01

    This work emphasizes the use of grid computing and web technology for automatic post-processing of brain magnetic resonance images (MRI) in the context of neuropsychiatric (Alzheimer's disease) research. Post-acquisition image processing is achieved through the interconnection of several individual processes into pipelines. Each process has input and output data ports, options and execution parameters, and performs single tasks such as: a) extracting individual image attributes (e.g. dimensions, orientation, center of mass), b) performing image transformations (e.g. scaling, rotation, skewing, intensity standardization, linear and non-linear registration), c) performing image statistical analyses, and d) producing the necessary quality control images and/or files for user review. The pipelines are built to perform specific sequences of tasks on the alphanumeric data and MRIs contained in our database. The web application is coded in PHP and allows the creation of scripts to create, store and execute pipelines and their instances either on our local cluster or on high-performance computing platforms. To run an instance on an external cluster, the web application opens a communication tunnel through which it copies the necessary files, submits the execution commands and collects the results. We present result on system tests for the processing of a set of 821 brain MRIs from the Alzheimer's Disease Neuroimaging Initiative study via a nonlinear registration pipeline composed of 10 processes. Our results show successful execution on both local and external clusters, and a 4-fold increase in performance if using the external cluster. However, the latter's performance does not scale linearly as queue waiting times and execution overhead increase with the number of tasks to be executed.

  7. Dedicated Magnetic Resonance Imaging in the Radiotherapy Clinic

    SciTech Connect

    Karlsson, Mikael Karlsson, Magnus G.; Nyholm, Tufve; Amies, Christopher; Zackrisson, Bjoern

    2009-06-01

    Purpose: To introduce a novel technology arrangement in an integrated environment and outline the logistics model needed to incorporate dedicated magnetic resonance (MR) imaging in the radiotherapy workflow. An initial attempt was made to analyze the value and feasibility of MR-only imaging compared to computed tomography (CT) imaging, testing the assumption that MR is a better choice for target and healthy tissue delineation in radiotherapy. Methods and Materials: A 1.5-T MR unit with a 70-cm-bore size was installed close to a linear accelerator, and a special trolley was developed for transporting patients who were fixated in advance between the MR unit and the accelerator. New MR-based workflow procedures were developed and evaluated. Results: MR-only treatment planning has been facilitated, thus avoiding all registration errors between CT and MR scans, but several new aspects of MR imaging must be considered. Electron density information must be obtained by other methods. Generation of digitally reconstructed radiographs (DRR) for x-ray setup verification is not straight forward, and reliable corrections of geometrical distortions must be applied. The feasibility of MR imaging virtual simulation has been demonstrated, but a key challenge to overcome is correct determination of the skeleton, which is often needed for the traditional approach of beam modeling. The trolley solution allows for a highly precise setup for soft tissue tumors without the invasive handling of radiopaque markers. Conclusions: The new logistics model with an integrated MR unit is efficient and will allow for improved tumor definition and geometrical precision without a significant loss of dosimetric accuracy. The most significant development needed is improved bone imaging.

  8. Magnetic resonance cholangiopancreatography image enhancement for automatic disease detection

    PubMed Central

    Logeswaran, Rajasvaran

    2010-01-01

    AIM: To sufficiently improve magnetic resonance cholangiopancreatography (MRCP) quality to enable reliable computer-aided diagnosis (CAD). METHODS: A set of image enhancement strategies that included filters (i.e. Gaussian, median, Wiener and Perona-Malik), wavelets (i.e. contourlet, ridgelet and a non-orthogonal noise compensation implementation), graph-cut approaches using lazy-snapping and Phase Unwrapping MAxflow, and binary thresholding using a fixed threshold and dynamic thresholding via histogram analysis were implemented to overcome the adverse characteristics of MRCP images such as acquisition noise, artifacts, partial volume effect and large inter- and intra-patient image intensity variations, all of which pose problems in application development. Subjective evaluation of several popular pre-processing techniques was undertaken to improve the quality of the 2D MRCP images and enhance the detection of the significant biliary structures within them, with the purpose of biliary disease detection. RESULTS: The results varied as expected since each algorithm capitalized on different characteristics of the images. For denoising, the Perona-Malik and contourlet approaches were found to be the most suitable. In terms of extraction of the significant biliary structures and removal of background, the thresholding approaches performed well. The interactive scheme performed the best, especially by using the strengths of the graph-cut algorithm enhanced by user-friendly lazy-snapping for foreground and background marker selection. CONCLUSION: Tests show promising results for some techniques, but not others, as viable image enhancement modules for automatic CAD systems for biliary and liver diseases. PMID:21160667

  9. Methodological challenges and solutions in auditory functional magnetic resonance imaging

    PubMed Central

    Peelle, Jonathan E.

    2014-01-01

    Functional magnetic resonance imaging (fMRI) studies involve substantial acoustic noise. This review covers the difficulties posed by such noise for auditory neuroscience, as well as a number of possible solutions that have emerged. Acoustic noise can affect the processing of auditory stimuli by making them inaudible or unintelligible, and can result in reduced sensitivity to auditory activation in auditory cortex. Equally importantly, acoustic noise may also lead to increased listening effort, meaning that even when auditory stimuli are perceived, neural processing may differ from when the same stimuli are presented in quiet. These and other challenges have motivated a number of approaches for collecting auditory fMRI data. Although using a continuous echoplanar imaging (EPI) sequence provides high quality imaging data, these data may also be contaminated by background acoustic noise. Traditional sparse imaging has the advantage of avoiding acoustic noise during stimulus presentation, but at a cost of reduced temporal resolution. Recently, three classes of techniques have been developed to circumvent these limitations. The first is Interleaved Silent Steady State (ISSS) imaging, a variation of sparse imaging that involves collecting multiple volumes following a silent period while maintaining steady-state longitudinal magnetization. The second involves active noise control to limit the impact of acoustic scanner noise. Finally, novel MRI sequences that reduce the amount of acoustic noise produced during fMRI make the use of continuous scanning a more practical option. Together these advances provide unprecedented opportunities for researchers to collect high-quality data of hemodynamic responses to auditory stimuli using fMRI. PMID:25191218

  10. A comparison study of microarrays by fluorescence imaging and surface plasmon resonance imaging

    NASA Astrophysics Data System (ADS)

    Liu, Zhiyi; Zhang, Chongwen; Yang, Bin; Chong, Xinyuan; Liu, Le; Ma, Suihua; He, Yonghong; Zhang, Guang; Guo, Jihua

    2009-08-01

    In the past decade the analysis of microarrays which are rich in biology information has generated considerable interest. One of the conventional techniques in this area is to detect the biomolecules labeled with fluorescence agents. In recent years, the surface plasmon resonance (SPR) imaging plays an important role in the detection of microarrays. The intensity of fluorescence signal acquired from fluorescence imaging is proportional to the amount of biomolecules, while the refractive index obtained from SPR imaging is relative to the concentration of sample, a comparison study of microarrays by these two detection techniques may be of great value. We develop a quasi-confocal parallel scan fluorescence imaging system which has only one moving part and can produce wide-field confocal images. The bacterial 16s rDNA universal primer labeled with CY5 fluorescence agents are used as probes and prepared as a microarray. The DNA-array is detected by both the quasi-confocal parallel scan fluorescence imaging system and the parallel scan spectral SPR imaging system. The results from these two imaging systems were compared and discussed in resolving power, homogeneity, etc. The refractive index information from the SPR imaging system and the fluorescence intensity information from the fluorescence imaging system are linked by bio-array concentration. The measured results can be inter-referred for bio-array studies.

  11. Magnetic resonance imaging volumetric and phosphorus 31 magnetic resonance spectroscopy measurements in schizophrenia.

    PubMed Central

    Hinsberger, A D; Williamson, P C; Carr, T J; Stanley, J A; Drost, D J; Densmore, M; MacFabe, G C; Montemurro, D G

    1997-01-01

    The purpose of this study was to examine the relationship between phosphorus magnetic resonance spectroscopy (31P MRS) parameters and left prefrontal volumes in both patients with schizophrenia and healthy subjects. 31P MRS parameters and magnetic resonance imaging (MRI) volumetric data were collected in the left prefrontal region in 10 patients with schizophrenia and 10 healthy subjects of comparable age, handedness, sex, educational level, and parental educational level. No correlations were found between any MRS parameter and grey matter volumes in the combined subjects. Phosphomonoester (PME) and grey matter volumes, however, were both correlated negatively with age. PMEs were found to be decreased, and calculated intracellular magnesium ([Mg2+]intra) was found to be increased in the patients with schizophrenia compared with healthy subjects after adjusting for left prefrontal grey and white matter, total brain volume, and age. These findings suggest that cortical grey and white manner volumes are not directly related to PME and [Mg2+]intra abnormalities in schizophrenia patients. Images Figure 1 Figure 2 PMID:9074305

  12. Towards simultaneous single emission microscopy and magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Cai, Liang

    In recent years, the combined nuclear imaging and magnetic resonance imaging (MRI) has drawn extensive research effort. They can provide simultaneously acquired anatomical and functional information inside the human/small animal body in vivo. In this dissertation, the development of an ultrahigh resolution MR-compatible SPECT (Single Photon Emission Computed Tomography) system that can be operated inside a pre-existing clinical MR scanner for simultaneous dual-modality imaging of small animals will be discussed. This system is constructed with 40 small pixel CdTe detector modules assembled in a fully stationary ring SPECT geometry. Series of experiments have demonstrated that this system is capable of providing an imaging resolution of <500?m, when operated inside MR scanners. The ultrahigh resolution MR-compatible SPECT system is built around a small pixel CdTe detector module that we recently developed. Each module consists of CdTe detectors having an overall size of 2.2 cm x 1.1 cm, divided into 64 x 32 pixels of 350 mum in size. A novel hybrid pixel-waveform (HPWF) readout system is also designed to alleviate several challenges for using small-pixel CdTe detectors in ultrahigh-resolution SPECT imaging applications. The HPWF system utilizes a modified version of a 2048-channel 2-D CMOS ASIC to readout the anode pixel, and a digitizing circuitry to sample the signal waveform induced on the cathode. The cathode waveform acquired with the HPWF circuitry offers excellent spatial resolution, energy resolution and depth of interaction (DOI) information, even with the presence of excessive charge-sharing/charge-loss between the small anode pixels. The HPWF CdTe detector is designed and constructed with a minimum amount of ferromagnetic materials, to ensure the MR-compatibility. To achieve sub-500?m imaging resolution, two special designed SPECT apertures have been constructed with different pinhole sizes of 300?m and 500?m respectively. It has 40 pinhole inserts that are made of cast platinum (90%)-iridium (10%) alloy, which provides the maximum stopping power and are compatible with MR scanners. The SPECT system is installed on a non-metal gantry constructed with 3-D printing using nylon powder material. This compact system can work as a "low-cost" desktop ultrahigh resolution SPECT system. It can also be directly operated inside an MR scanner. Accurate system geometrical calibration and corresponding image reconstruction methods for the MRC-SPECT system is developed. In order to account for the magnetic field induced distortion in the SPECT image, a comprehensive charge collection model inside strong magnetic field is adopted to produce high resolution SPECT image inside MR scanner.

  13. Wavelet Domain Radiofrequency Pulse Design Applied to Magnetic Resonance Imaging

    PubMed Central

    Huettner, Andrew M.; Mickevicius, Nikolai J.; Ersoz, Ali; Koch, Kevin M.; Muftuler, L. Tugan; Nencka, Andrew S.

    2015-01-01

    A new method for designing radiofrequency (RF) pulses with numerical optimization in the wavelet domain is presented. Numerical optimization may yield solutions that might otherwise have not been discovered with analytic techniques alone. Further, processing in the wavelet domain reduces the number of unknowns through compression properties inherent in wavelet transforms, providing a more tractable optimization problem. This algorithm is demonstrated with simultaneous multi-slice (SMS) spin echo refocusing pulses because reduced peak RF power is necessary for SMS diffusion imaging with high acceleration factors. An iterative, nonlinear, constrained numerical minimization algorithm was developed to generate an optimized RF pulse waveform. Wavelet domain coefficients were modulated while iteratively running a Bloch equation simulator to generate the intermediate slice profile of the net magnetization. The algorithm minimizes the L2-norm of the slice profile with additional terms to penalize rejection band ripple and maximize the net transverse magnetization across each slice. Simulations and human brain imaging were used to demonstrate a new RF pulse design that yields an optimized slice profile and reduced peak energy deposition when applied to a multiband single-shot echo planar diffusion acquisition. This method may be used to optimize factors such as magnitude and phase spectral profiles and peak RF pulse power for multiband simultaneous multi-slice (SMS) acquisitions. Wavelet-based RF pulse optimization provides a useful design method to achieve a pulse waveform with beneficial amplitude reduction while preserving appropriate magnetization response for magnetic resonance imaging. PMID:26517262

  14. Influence of open and sealed fractures on fluid flow and water saturation in sandstone cores using Magnetic Resonance Imaging

    E-print Network

    Magnetic Resonance Imaging S. Baraka-Lokmane,1,2 G. Teutsch1 and I. G. Main2 1 Department of Applied form 2000 July 3 SUMMARY We use Magnetic Resonance Imaging (MRI) to image the imbibition of water saturation. 1 I N T R O D U C T I O N Magnetic resonance imaging (MRI) is now established as an important

  15. Towards magnetic resonance imaging guided radiation therapy (MRIgRT)

    NASA Astrophysics Data System (ADS)

    Stanescu, Teodor Marius

    The goal of this work is to address key aspects of the magnetic resonance imaging guided radiation therapy (MRIgRT) process of cancer sites. MRIgRT is implemented by using a system comprised of a magnetic resonance imaging (MRI) scanner coupled with a radiation source, in our case a radiotherapy accelerator (Linac). The potential benefits of MRIgRT are the real-time tracking of the tumor and neighbouring healthy anatomy during treatment irradiation leading to on-line treatment plan optimization. Ultimately, this results in an increased accuracy and efficiency of the overall treatment process. A large research effort is conducted at Cross Cancer Institute to develop a hybrid MRI-Linac system consisting of a bi-planar 0.2 T permanent magnet coupled with a 6 MV Linac. The present work is part of this project and aims to address the following key components: (a) magnetic shielding and dosimetric effects of the MRI-Linac system, (b) measure and correction of scanner-related MR image distortions, and (c) MRI-based treatment planning procedure for intracranial lesions. The first two components are essential for the optimal construction and operation of the MRI-Linac system while the third one represents a direct application of the system. The linac passive shielding was achieved by (a) adding two 10 cm thick steel (1020) plates placed at a distance of 10 cm from the structure on opposite sides of the magnet; and (b) a box lined with a 1 mm MuMetal(TM) wall surrounding the Linac. For our proposed MRI-Linac configuration (i.e. 0.2 T field and rotating bi-planar geometry) the maximum dose difference from zero magnetic field case was found to be within 6% and 12% in a water and water-lung-water phantom, respectively. We developed an image system distortion correction method for MRI that relies on adaptive thresholding and an iterative algorithm to determine the 3D distortion field. Applying this technique the residual image distortions were reduced to within the voxel resolution of the raw imaging data. We investigated a procedure for the MRI Simulation of brain lesions which consists of (a) correction of MR images for 3D distortions, (b) automatic segmentation of head sub-structures (i.e. scalp, bone, and brain) relevant for dosimetric calculations, (c) conversion of MRI datasets into CT-like images by assigning bulk CT values to head sub-structures and MRI-based dose calculations, and (d) RT plan evaluation based on isodose distributions, dosimetric parameters, dose volume histograms, and an RT ranking tool. The proposed MRI-based treatment planning procedure performed similarly to the standard clinical technique, which relies on both CT and MR imaging modalities, and is suitable for the radiotherapy of brain cancer.

  16. What roles are there for magnetic resonance imaging in process tomography?

    NASA Astrophysics Data System (ADS)

    Gibbs, S. J.; Hall, L. D.

    1996-05-01

    Currently pursued technologies and requirements for process tomography are briefly reviewed with emphasis on comparing existing methods and identifying roles for magnetic resonance techniques. It is concluded that fundamental studies of transport phenomena are among the beneficial applications of magnetic resonance techniques. After a brief review of the theory of magnetic resonance and a description of modern hardware for magnetic resonance imaging, specific examples of magnetic resonance investigations of mass and heat transfer are presented including studies of thermal processing, multiphase distributions, polymerization, and diffusion and flow. We conclude by speculating on future roles of NMR imaging for process developement and monitoring.

  17. Imaging Atherosclerosis with Hybrid Positron Emission Tomography/Magnetic Resonance Imaging

    PubMed Central

    Kjær, Andreas

    2015-01-01

    Noninvasive imaging of atherosclerosis could potentially move patient management towards individualized triage, treatment, and followup. The newly introduced combined positron emission tomography (PET) and magnetic resonance imaging (MRI) system could emerge as a key player in this context. Both PET and MRI have previously been used for imaging plaque morphology and function: however, the combination of the two methods may offer new synergistic opportunities. Here, we will give a short summary of current relevant clinical applications of PET and MRI in the setting of atherosclerosis. Additionally, our initial experiences with simultaneous PET/MRI for atherosclerosis imaging are presented. Finally, future potential vascular applications exploiting the unique combination of PET and MRI will be discussed. PMID:25695091

  18. Concurrent multiscale imaging with magnetic resonance imaging and optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Liang, Chia-Pin; Yang, Bo; Kim, Il Kyoon; Makris, George; Desai, Jaydev P.; Gullapalli, Rao P.; Chen, Yu

    2013-04-01

    We develop a novel platform based on a tele-operated robot to perform high-resolution optical coherence tomography (OCT) imaging under continuous large field-of-view magnetic resonance imaging (MRI) guidance. Intra-operative MRI (iMRI) is a promising guidance tool for high-precision surgery, but it may not have sufficient resolution or contrast to visualize certain small targets. To address these limitations, we develop an MRI-compatible OCT needle probe, which is capable of providing microscale tissue architecture in conjunction with macroscale MRI tissue morphology in real time. Coregistered MRI/OCT images on ex vivo chicken breast and human brain tissues demonstrate that the complementary imaging scales and contrast mechanisms have great potential to improve the efficiency and the accuracy of iMRI procedure.

  19. Multimodality magnetic resonance imaging in hepatic encephalopathy: An update

    PubMed Central

    Zhang, Xiao-Dong; Zhang, Long-Jiang; Wu, Sheng-Yong; Lu, Guang-Ming

    2014-01-01

    Hepatic encephalopathy (HE) is a neuropsychiatric complication of cirrhosis or acute liver failure. Currently, HE is regarded as a continuous cognitive impairment ranging from the mildest stage, minimal HE to overt HE. Hyperammonaemia and neuroinflammation are two main underlying factors which contribute to the neurological alterations in HE. Both structural and functional impairments are found in the white mater and grey mater involved in HE. Although the investigations into HE pathophysiological mechanism are enormous, the exact pathophysiological causes underlying HE remain controversial. Multimodality magnetic resonance imaging (MRI) plays an important role in helping to understand the pathological process of HE. This paper reviews the up-to-date multimodality MRI methods and predominant findings in HE patients with a highlight of the increasingly important role of blood oxygen level dependent functional MRI. PMID:25170210

  20. Magnetic resonance imaging of the neck. Part II. Pathologic findings

    SciTech Connect

    Stark, D.D.; Moss, A.A.; Gamsu, G.; Clark, O.H.; Gooding, G.A.W.; Webb, W.R.

    1984-02-01

    Magnetic resonance (MR) images of the neck were obtained in 14 patients with thyroid, parathyroid, lymph node, or laryngeal lesions. Tumors and lymph nodes were more easily differentiated from muscle and blood vessels with MR than with CT because of the superior soft tissue contrast of MR. Tissue characterization allowed MR differentiation of thyroid nodules, thyroid cysts, and parathyroid tumors from normal thyroid tissue; however, nonspecifically increased T1 and T2 relaxation times overlapped for a variety of neoplastic and inflammatory conditions. Thyroid cyst fluid had the greatest water content and longest T1 and T2 times of all tissues studied. Parathyroid hyperplasia could not be differentiated from parathyroid adenoma; however, parathyroid tumors had slightly longer T1 and T2 times than thyroid nodules or lymph nodes. With further experience, MR tissue characterization may become a useful technique for evaluating neck masses.

  1. Magnetic resonance imaging of living systems by remote detection

    DOEpatents

    Wemmer, David; Pines, Alexander; Bouchard, Louis; Xu, Shoujun; Harel, Elad; Budker, Dmitry; Lowery, Thomas; Ledbetter, Micah

    2013-10-29

    A novel approach to magnetic resonance imaging is disclosed. Blood flowing through a living system is prepolarized, and then encoded. The polarization can be achieved using permanent or superconducting magnets. The polarization may be carried out upstream of the region to be encoded or at the place of encoding. In the case of an MRI of a brain, polarization of flowing blood can be effected by placing a magnet over a section of the body such as the heart upstream of the head. Alternatively, polarization and encoding can be effected at the same location. Detection occurs at a remote location, using a separate detection device such as an optical atomic magnetometer, or an inductive Faraday coil. The detector may be placed on the surface of the skin next to a blood vessel such as a jugular vein carrying blood away from the encoded region.

  2. Synovial Hemangioma of the Knee Joint: Magnetic Resonance Imaging Findings

    PubMed Central

    Guler, Ibrahim; Nayman, Alaaddin; Koplay, Mustafa; Paksoy, Yahya

    2015-01-01

    Summary Background Synovial hemangioma is benign tumor of the joints and is seen relatively rare. The most affected joint is knee but should also be seen in other joints. The disease is usually symptomatic. They are classified as juxta-articular haemangioma, intra-articular haemangioma or an intermediate type of hemangioma with intra- and extraarticular components. Case Report A 19-years-old male patient presented with swollen and painful knee. The laboratory findings and physical examination were normal. MRI demonstrated a large lesion that was filling the suprapatellar bursa. Conclusions All radiologic examinations should be used in diagnosis but magnetic resonance imaging is the non-invasive method and excellent modality in the evaluation of soft tissues. In this paper, a 19-year-old male patient with the diagnosis of synovial hemangioma is reported and its radiologic findings are mentioned. PMID:26491492

  3. Utility of Magnetic Resonance Imaging in Cardiac Venous Anatomic Variants

    SciTech Connect

    Eckart, Robert E. Leitch, W. Shad; Shry, Eric A.; Krasuski, Richard A.; Lane, Michael J.; Leclerc, Kenneth M.

    2003-06-15

    The incidence of persistent left superior venacava (PLSVC) is approximately 0.5% in the general population; however,the coexistent absence of the right SVC has a reported incidence in tertiary centers of 0.1%. The vast majority of reports are limited to pediatric cardiology. Likewise, sinus of Valsalva aneurysm is a rare congenital anomaly, with a reported incidence of 0.1-3.5% of all congenital heart defects. We present a 71-year-old patient undergoing preoperative evaluation for incidental finding of aortic root aneurysm,and found to have all three in coexistence. Suggestive findings were demonstrated on cardiac catheterization and definitive diagnosis was made by magnetic resonance imaging. The use of MRI for the diagnosis of asymptomatic adult congenital heart disease will be reviewed.

  4. Magnetic resonance imaging for patients with cardiac implantable electrical devices

    PubMed Central

    Chow, Grant V.; Nazarian, Saman

    2014-01-01

    Magnetic resonance imaging (MRI) has become an invaluable tool in the evaluation of both soft tissue and bony abnormalities, with an increasing number of studies ordered per year. The presence of a cardiac implantable electrical device (CIED) may complicate matters, however, as these devices are currently considered a relative contraindication to MRI scanning. When performed in patients with a CIED, risks of MRI include reed switch activation in older devices, lead heating, system malfunction, and significant radiofrequency noise resulting in inappropriate inhibition of demand pacing, tachycardia therapies, or programming changes. This report reviews the common indications and risk-benefit evaluation of MRI in patients with CIED, and provides a clinical algorithm which has been successfully implemented at our institution for performing MRI in patients with implanted devices. PMID:24793805

  5. Magnetic resonance imaging of transfusional hemosiderosis complicating thalassemia major

    SciTech Connect

    Brasch, R.C.; Wesbey, G.E.; Gooding, C.A.; Koerper, M.A.

    1984-03-01

    Tissue deposits of hemosiderin, a paramagnetic iron-protein complex, resulted in marked abnormalities of magnetic resonance (MR) spin-echo signal intensity within the viscera of three children with transfusional hemosiderosis and thalassemia major. In all patients the liver and bone marrow demonstrated abnormally low spin-echo intensities and the kidneys and muscles had abnormally high intensities. These observations correlate with in vitro MR observation of ferric (Fe/sup +3/) solutions, in which concentrations of ferric salts greater than 20 mmol yielded higher intensities than did water alone. MR imaging is sensitive to the tissue deposition of hemosiderin, and MR intensity appears to provide a rough measure of the amount of iron deposited.

  6. Electron beam imaging and spectroscopy of plasmonic nanoantenna resonances

    NASA Astrophysics Data System (ADS)

    Vesseur, E. J. R.

    2011-07-01

    Nanoantennas are metal structures that provide strong optical coupling between a nanoscale volume and the far field. This coupling is mediated by surface plasmons, oscillations of the free electrons in the metal. Increasing the control over the resonant plasmonic field distribution opens up a wide range of applications of nanoantennas operating both in receiving and transmitting mode. This thesis presents how the dispersion and confinement of surface plasmons in nanoantennas are resolved and further engineered. Fabrication of nanostructures is done using focused ion beam milling (FIB) in metallic surfaces. We demonstrate that patterning in single-crystal substrates allows us to precisely control the geometry in which plasmons are confined. The nanoscale properties of the resonant plasmonic fields are resolved using a new technique developed in this thesis: angle- and polarization controlled cathodoluminescence (CL) imaging spectroscopy. The use of a tightly focused electron beam allows us to probe the optical antenna properties with deep subwavelength resolution. We show using this technique that nanoantennas consisting of 500-1200 nm long polycrystalline Au nanowires support standing plasmon waves. We directly observe the plasmon wavelengths which we use to derive the dispersion relation of guided nanowire plasmons. A 590-nm-long ridge-shaped nanoantenna was fabricated using FIB milling on a single-crystal Au substrate, demonstrating a level of control over the fabrication impossible with polycrystalline metals. CL experiments show that the ridge supports multiple-order resonances. The confinement of surface plasmons to the ridge is confirmed by boundary-element-method (BEM) calculations. The resonant modes in plasmonic whispering gallery cavities consisting of a FIB-fabricated circular groove are resolved. We find an excellent agreement between boundary element method calculations and the measured CL emission from the ring-shaped cavities. The calculations show that the ring supports resonances with increasing azimuthal or radial order. The smallest cavity fits only one wavelength in its circumference. We theoretically show that in these cavities, spontaneous emission can be enhanced over a broad spectral band due to the small modal volume of the plasmon resonances. A Purcell factor >2000 was found. We further study the mode symmetries and coupling of the ring resonances using far-field excitation, fluorescence, angle-resolved cathodoluminescence and photoelectron emission microscopy. We demonstrate spectral reshaping of emitters, mode-specific angular emission patterns, and a mode-selective excitation by incoming light, and we directly resolve the modal fields at high resolution. In the next chapter, we present metal-insulator-metal plasmon waveguides in which we engineer the dispersion to reach a refractive index of zero. Using spatially- and angle-resolved CL we directly observe the spatial mode profiles and determine the dispersion relation of plasmon modes. At the cutoff frequency, the emission pattern corresponds to that of a line dipole antenna demonstrating the entire waveguide is in phase (n=0). A strongly enhanced density of optical states is directly observed at cutoff from the enhanced CL intensity. Finally, we present 5 possible applications: a localized surface plasmon sensor, a plasmon ring laser, template stripping technique, an in-situ monitor of ionoluminescence and cathodoluminescence in a FIB system and a single-photon source.

  7. Nanostructured surfaces for surface plasmon resonance spectroscopy and imaging

    NASA Astrophysics Data System (ADS)

    Petefish, Joseph W.

    Surface plasmon resonance (SPR) has achieved widespread recognition as a sensitive, label-free, and versatile optical method for monitoring changes in refractive index at a metal-dielectric interface. Refractive index deviations of 10-6 RIU are resolvable using SPR, and the method can be used in real-time or ex-situ. Instruments based on carboxymethyl dextran coated SPR chips have achieved commercial success in biological detection, while SPR sensors can also be found in other fields as varied as food safety and gas sensing. Chapter 1 provides a physical background of SPR sensing. A brief history of the technology is presented, and publication data are included that demonstrate the large and growing interest in surface plasmons. Numerous applications of SPR sensors are listed to illustrate the broad appeal of the method. Surface plasmons (SPs) and surface plasmon polaritions (SPPs) are formally defined, and important parameters governing their spatial behavior are derived from Maxwell's equations and appropriate boundary conditions. Physical requirements for exciting SPs with incident light are discussed, and SPR imaging is used to illustrate the operating principle of SPR-based detection. Angle-tunable surface enhanced infrared absorption (SEIRA) of polymer vibrational modes via grating-coupled SPR is demonstrated in Chapter 2. Over 10-fold enhancement of C-H stretching modes was found relative to the absorbance of the same film in the absence of plasmon excitation. Modeling results are used to support and explain experimental observations. Improvements to the grating coupler SEIRA platform in Chapter 2 are explored in Chapters 3 and 4. Chapter 3 displays data for two sets of multipitch gratings: one set with broadly distributed resonances with the potential for multiband IR enhancement and the other with finely spaced, overlapping resonances to form a broadband IR enhancement device. Diffraction gratings having multiple periods were fabricated using a Lloyd's mirror interferometer to perform multiple exposures at multiple angles before developing. Precise control of the resonance position is shown by locating three SPR dips at predetermined wavenumbers of 5000, 4000, and 3000 cm-1, respectively. A set of three gratings, each having four closely spaced resonances is employed to show how the sensor response could be broadened. The work in Chapter 3 shows potential for simultaneous enhancement of multiple vibrational modes; the multiband approach might find application for modes at disparate locations within the IR spectrum, while the broadband approach may allow concurrent probing of broad single modes or clusters of narrow modes within a particular neighborhood of the spectrum. Chapter 4 uses the rigorous coupled-wave analysis (RCWA) method to numerically explore another facet of the nanostructure-based tunability of grating-baed SPR sensing. The work in this chapter illustrates how infrared signal enhancement could be tailored by through adjustment of the grating amplitude. Modeled infrared reflection absorption (IRRAS) spectra and electric field distributions were generated for several nanostructured grating configurations. It was found that there exists a critical amplitude value for a given grating pitch where the plasmon response achieves a maximum. Amplitudes greater than this critical value produce a broader and attenuated plasmon peak, while smaller amplitudes produce a plasmon resonance that is not as intense. Field simulations show how amplitudes nearer the critical amplitude resulted in large increases in the electric field within an analyte film atop the sensor surface, and the relative strength of the increased field is predictable based on the appearance of the IRRAS spectra. It is believed that these larger fields are the cause of observed enhanced absorption. Published reports pertaining to interactions of SPs with molecular resonance and to diffraction-based tracking of plasmons without a spectrometer are included in the Appendix to this thesis. In the first of the two reports, it is shown that plasmons

  8. Functional imaging as an indicator of diagnostic information in cardiac magnetic-resonance images

    NASA Astrophysics Data System (ADS)

    Klingler, Joseph W.; Andrews, Lee T.; Begeman, Michael S.; Zeiss, Jacob; Leighton, Richard F.

    1990-08-01

    Magnetic Resonance (MR) images of the human heart provide three dimensional geometric information about the location of cardiac structures throughout the cardiac cycle. Analysis of this four dimensional data set allows detection of abnormal cardiac function related to the presence of coronary artery disease. To assist in this analysis, quantitative measurements of cardiac performance are made from the MR data including ejection fractions, regional wall motion and myocardial wall thickening. Analysis of cardiac performance provided by quantitative analysis of MR data can be aided by computer graphics presentation techniques. Two and three dimensional functional images are computed to indicate regions of abnormality based on the previous methods. The two dimensional images are created using color graphics overlays on the original MR image to represent performance. Polygon surface modeling techniques are used to represent data which is three dimensional, such as blood pool volumes. The surface of these images are color encoded by regional ejection fraction, wall motion or wall thickening. A functional image sequence is constructed at each phase of the cardiac cycle and displayed as a movie loop for review by the physician. Selection of a region on the functional image allows visual interpretation of the original MR images, graphical plots of cardiac function and tabular results. Color encoding is based on absolute measurements and comparison to standard normal templates of cardiac performance.

  9. Development of the 1.2?T~1.5?T Permanent Magnetic Resonance Imaging Device and Its Application for Mouse Imaging

    PubMed Central

    Wang, Guangxin; Xie, Huantong; Hou, Shulian; Chen, Wei; Zhao, Qiang; Li, Shiyu

    2015-01-01

    By improving the main magnet, gradient, and RF coils design technology, manufacturing methods, and inventing new magnetic resonance imaging (MRI) special alloy, a cost-effective and small animal specific permanent magnet-type three-dimensional magnetic resonance imager was developed. The main magnetic field strength of magnetic resonance imager with independent intellectual property rights is 1.2~1.5?T. To demonstrate its effectiveness and validate the mouse imaging experiments in different directions, we compared the images obtained by small animal specific permanent magnet-type three-dimensional magnetic resonance imager with that obtained by using superconductor magnetic resonance imager for clinical diagnosis. PMID:26539531

  10. Functional imaging of the human placenta with magnetic resonance.

    PubMed

    Siauve, Nathalie; Chalouhi, Gihad E; Deloison, Benjamin; Alison, Marianne; Clement, Olivier; Ville, Yves; Salomon, Laurent J

    2015-10-01

    Abnormal placentation is responsible for most failures in pregnancy; however, an understanding of placental functions remains largely concealed from noninvasive, in vivo investigations. Magnetic resonance imaging (MRI) is safe in pregnancy for magnetic fields of up to 3 Tesla and is being used increasingly to improve the accuracy of prenatal imaging. Functional MRI (fMRI) of the placenta has not yet been validated in a clinical setting, and most data are derived from animal studies. FMRI could be used to further explore placental functions that are related to vascularization, oxygenation, and metabolism in human pregnancies by the use of various enhancement processes. Dynamic contrast-enhanced MRI is best able to quantify placental perfusion, permeability, and blood volume fractions. However, the transplacental passage of Gadolinium-based contrast agents represents a significant safety concern for this procedure in humans. There are alternative contrast agents that may be safer in pregnancy or that do not cross the placenta. Arterial spin labeling MRI relies on magnetically labeled water to quantify the blood flows within the placenta. A disadvantage of this technique is a poorer signal-to-noise ratio. Based on arterial spin labeling, placental perfusion in normal pregnancy is 176 ± 91 mL × min(-1) × 100 g(-1) and decreases in cases with intrauterine growth restriction. Blood oxygen level-dependent and oxygen-enhanced MRIs do not assess perfusion but measure the response of the placenta to changes in oxygen levels with the use of hemoglobin as an endogenous contrast agent. Diffusion-weighted imaging and intravoxel incoherent motion MRI do not require exogenous contrast agents, instead they use the movement of water molecules within tissues. The apparent diffusion coefficient and perfusion fraction are significantly lower in placentas of growth-restricted fetuses when compared with normal pregnancies. Magnetic resonance spectroscopy has the ability to extract information regarding metabolites from the placenta noninvasively and in vivo. There are marked differences in all 3 metabolites N-acetyl aspartate/choline levels, inositol/choline ratio between small, and adequately grown fetuses. Current research is focused on the ability of each fMRI technique to make a timely diagnosis of abnormal placentation that would allow for appropriate planning of follow-up examinations and optimal scheduling of delivery. These research programs will benefit from the use of well-defined sequences, standardized imaging protocols, and robust computational methods. PMID:26428488

  11. In vivo magnetic resonance imaging and spectroscopy identifies oncolytic adenovirus responders

    E-print Network

    Hemminki, Akseli

    In vivo magnetic resonance imaging and spectroscopy identifies oncolytic adenovirus responders O-induced tumor swel- ling. We hypothesized that magnetic resonance imaging (MRI) and spectroscopy (MRS) might- ities such as computed tomography (CT), which measure tumor size, are unreliable owing to inflammation

  12. Prefrontal Cortical Thickness in First-Episode Psychosis: A Magnetic Resonance Imaging Study

    E-print Network

    Prefrontal Cortical Thickness in First-Episode Psychosis: A Magnetic Resonance Imaging Study Laura, cortical thickness in first-episode schizophrenia has not been evaluated using magnetic resonance imaging, see Miller 1999). Functional studies (i.e., positron emission tomography [PET] and functional magnetic

  13. Abstract--Magnetic Resonance Imaging (MRI) guided nanorobotic systems that could perform diagnostic, curative

    E-print Network

    Mavroidis, Constantinos

    Abstract-- Magnetic Resonance Imaging (MRI) guided nanorobotic systems that could perform drug delivery systems guided by Magnetic Resonance Imaging (MRI) scanners have been proposed on the use of a MRI scanner to induce the required external driving forces to guide magnetic nanocapsules

  14. In Vivo Magnetic Resonance Imaging of Mesenchymal Stem Cells in Myocardial Infarction

    E-print Network

    Atalar, Ergin

    In Vivo Magnetic Resonance Imaging of Mesenchymal Stem Cells in Myocardial Infarction Dara L-MSCs) in a swine myocardial infarction (MI) model. Methods and Results--Adult farm pigs (n 5) were subjected;107:2290-2293.) Key Words: magnetic resonance imaging myocardial infarction cells contrast media Because

  15. PTFOS: Flexible and Absorbable Intracranial Electrodes for Magnetic Resonance Imaging

    PubMed Central

    Bonmassar, Giorgio; Fujimoto, Kyoko; Golby, Alexandra J.

    2012-01-01

    Intracranial electrocortical recording and stimulation can provide unique knowledge about functional brain anatomy in patients undergoing brain surgery. This approach is commonly used in the treatment of medically refractory epilepsy. However, it can be very difficult to integrate the results of cortical recordings with other brain mapping modalities, particularly functional magnetic resonance imaging (fMRI). The ability to integrate imaging and electrophysiological information with simultaneous subdural electrocortical recording/stimulation and fMRI could offer significant insight for cognitive and systems neuroscience as well as for clinical neurology, particularly for patients with epilepsy or functional disorders. However, standard subdural electrodes cause significant artifact in MRI images, and concerns about risks such as cortical heating have generally precluded obtaining MRI in patients with implanted electrodes. We propose an electrode set based on polymer thick film organic substrate (PTFOS), an organic absorbable, flexible and stretchable electrode grid for intracranial use. These new types of MRI transparent intracranial electrodes are based on nano-particle ink technology that builds on our earlier development of an EEG/fMRI electrode set for scalp recording. The development of MRI-compatible recording/stimulation electrodes with a very thin profile could allow functional mapping at the individual subject level of the underlying feedback and feed forward networks. The thin flexible substrate would allow the electrodes to optimally contact the convoluted brain surface. Performance properties of the PTFOS were assessed by MRI measurements, finite difference time domain (FDTD) simulations, micro-volt recording, and injecting currents using standard electrocortical stimulation in phantoms. In contrast to the large artifacts exhibited with standard electrode sets, the PTFOS exhibited no artifact due to the reduced amount of metal and conductivity of the electrode/trace ink and had similar electrical properties to a standard subdural electrode set. The enhanced image quality could enable routine MRI exams of patients with intracranial electrode implantation and could also lead to chronic implantation solutions. PMID:22984396

  16. Fetal imaging by nuclear magnetic resonance: a study in goats: work in progress

    SciTech Connect

    Foster, M.A.; Knight, C.H.; Rimmington, J.E.; Mallard, J.R.

    1983-10-01

    Nuclear magnetic resonance proton imaging was used to obtain images of goat fetuses in utero. The long T1 relaxation time of amniotic fluid makes it appear black on proton density images when examined using the Aberdeen imager, and so allows very good discrimination of the position and structure of the fetus. Some fetal internal tissues can be seen on T1 images. These findings suggest that NMR imaging has great potential in pregnancy studies.

  17. Advances in Magnetic Resonance Imaging of the Skull Base

    PubMed Central

    Kirsch, Claudia F.E.

    2014-01-01

    Introduction?Over the past 20 years, magnetic resonance imaging (MRI) has advanced due to new techniques involving increased magnetic field strength and developments in coils and pulse sequences. These advances allow increased opportunity to delineate the complex skull base anatomy and may guide the diagnosis and treatment of the myriad of pathologies that can affect the skull base. Objectives?The objective of this article is to provide a brief background of the development of MRI and illustrate advances in skull base imaging, including techniques that allow improved conspicuity, characterization, and correlative physiologic assessment of skull base pathologies. Data Synthesis?Specific radiographic illustrations of increased skull base conspicuity including the lower cranial nerves, vessels, foramina, cerebrospinal fluid (CSF) leaks, and effacement of endolymph are provided. In addition, MRIs demonstrating characterization of skull base lesions, such as recurrent cholesteatoma versus granulation tissue or abscess versus tumor, are also provided as well as correlative clinical findings in CSF flow studies in a patient pre- and post-suboccipital decompression for a Chiari I malformation. Conclusions?This article illustrates MRI radiographic advances over the past 20 years, which have improved clinicians' ability to diagnose, define, and hopefully improve the treatment and outcomes of patients with underlying skull base pathologies. PMID:25992137

  18. [Diagnosis. Radiological study. Ultrasound, computed tomography and magnetic resonance imaging].

    PubMed

    Gallo Vallejo, Francisco Javier; Giner Ruiz, Vicente

    2014-01-01

    Because of its low cost, availability in primary care and ease of interpretation, simple X-ray should be the first-line imaging technique used by family physicians for the diagnosis and/or follow-up of patients with osteoarthritis. Nevertheless, this technique should only be used if there are sound indications and if the results will influence decision-making. Despite the increase of indications in patients with rheumatological disease, the role of ultrasound in patients with osteoarthritis continues to be limited. Computed tomography (CT) is of some -although limited- use in osteoarthritis, especially in the study of complex joints (such as the sacroiliac joint and facet joints). Magnetic resonance imaging (MRI) has represented a major advance in the evaluation of joint cartilage and subchondral bone in patients with osteoarthritis but, because of its high cost and diagnostic-prognostic yield, this technique should only be used in highly selected patients. The indications for ultrasound, CT and MRI in patients with osteoarthritis continue to be limited in primary care and often coincide with situations in which the patient may require hospital referral. Patient safety should be bourne in mind. Patients should be protected from excessive ionizing radiation due to unnecessary repeat X-rays or inadequate views or to requests for tests such as CT, when not indicated. PMID:24467957

  19. Molecular magnetic resonance imaging of brain–immune interactions

    PubMed Central

    Gauberti, Maxime; Montagne, Axel; Quenault, Aurélien; Vivien, Denis

    2014-01-01

    Although the blood–brain barrier (BBB) was thought to protect the brain from the effects of the immune system, immune cells can nevertheless migrate from the blood to the brain, either as a cause or as a consequence of central nervous system (CNS) diseases, thus contributing to their evolution and outcome. Accordingly, as the interface between the CNS and the peripheral immune system, the BBB is critical during neuroinflammatory processes. In particular, endothelial cells are involved in the brain response to systemic or local inflammatory stimuli by regulating the cellular movement between the circulation and the brain parenchyma. While neuropathological conditions differ in etiology and in the way in which the inflammatory response is mounted and resolved, cellular mechanisms of neuroinflammation are probably similar. Accordingly, neuroinflammation is a hallmark and a decisive player of many CNS diseases. Thus, molecular magnetic resonance imaging (MRI) of inflammatory processes is a central theme of research in several neurological disorders focusing on a set of molecules expressed by endothelial cells, such as adhesion molecules (VCAM-1, ICAM-1, P-selectin, E-selectin, …), which emerge as therapeutic targets and biomarkers for neurological diseases. In this review, we will present the most recent advances in the field of preclinical molecular MRI. Moreover, we will discuss the possible translation of molecular MRI to the clinical setting with a particular emphasis on myeloperoxidase imaging, autologous cell tracking, and targeted iron oxide particles (USPIO, MPIO). PMID:25505871

  20. Stable cerasomes for simultaneous drug delivery and magnetic resonance imaging

    PubMed Central

    Cao, Zhong; Zhu, Wenjian; Wang, Wei; Zhang, Chunyang; Xu, Ming; Liu, Jie; Feng, Shi-Ting; Jiang, Qing; Xie, Xiaoyan

    2014-01-01

    Magnetic liposomes have been frequently used as nanocarriers for targeted drug delivery and magnetic resonance imaging in recent years. Despite great potentials, their morphological/structural instability in the physiological environment still remains an intractable challenge for clinical applications. In this study, stable hybrid liposomal cerasomes (ie, liposomes partially coated with silica) which can co-encapsulate Fe3O4 nanoparticles and the anticancer drug paclitaxel were developed using thin film hydration method. Compared with the drug loaded liposomes, the paclitaxel-loaded magnetic cerasomes (PLMCs) exhibited much higher storage stability and better sustained release behavior. Cellular uptake study showed that the utilization of an external magnetic field significantly facilitated the internalization of PLMCs into cancer cells, resulting in potentiated drug efficacy of killing tumor cells. The T2 relaxivity (r2) of our PLMCs was much higher than that of free Fe3O4 nanoparticles, suggesting increased sensitivity in T2-weighted imaging. Given its excellent biocompatibility also shown in the study, such dual functional PLMC is potentially a promising nanosystem for effective cancer diagnosis and therapy. PMID:25395848

  1. Radio-frequency energy quantification in magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Alon, Leeor

    Mapping of radio frequency (RF) energy deposition has been challenging for 50+ years, especially, when scanning patients in the magnetic resonance imaging (MRI) environment. As result, electromagnetic simulation software is often used for estimating the specific absorption rate (SAR), the rate of RF energy deposition in tissue. The thesis work presents challenges associated with aligning information provided by electromagnetic simulation and MRI experiments. As result of the limitations of simulations, experimental methods for the quantification of SAR were established. A system for quantification of the total RF energy deposition was developed for parallel transmit MRI (a system that uses multiple antennas to excite and image the body). The system is capable of monitoring and predicting channel-by-channel RF energy deposition, whole body SAR and capable of tracking potential hardware failures that occur in the transmit chain and may cause the deposition of excessive energy into patients. Similarly, we demonstrated that local RF power deposition can be mapped and predicted for parallel transmit systems based on a series of MRI temperature mapping acquisitions. Resulting from the work, we developed tools for optimal reconstruction temperature maps from MRI acquisitions. The tools developed for temperature mapping paved the way for utilizing MRI as a diagnostic tool for evaluation of RF/microwave emitting device safety. Quantification of the RF energy was demonstrated for both MRI compatible and non-MRI-compatible devices (such as cell phones), while having the advantage of being noninvasive, of providing millimeter resolution and high accuracy.

  2. Quantum control of proximal spins using nanoscale magnetic resonance imaging

    E-print Network

    M. S. Grinolds; P. Maletinsky; S. Hong; M. D. Lukin; R. L Walsworth; A. Yacoby

    2011-03-02

    Quantum control of individual spins in condensed matter systems is an emerging field with wide-ranging applications in spintronics, quantum computation, and sensitive magnetometry. Recent experiments have demonstrated the ability to address and manipulate single electron spins through either optical or electrical techniques. However, it is a challenge to extend individual spin control to nanoscale multi-electron systems, as individual spins are often irresolvable with existing methods. Here we demonstrate that coherent individual spin control can be achieved with few-nm resolution for proximal electron spins by performing single-spin magnetic resonance imaging (MRI), which is realized via a scanning magnetic field gradient that is both strong enough to achieve nanometric spatial resolution and sufficiently stable for coherent spin manipulations. We apply this scanning field-gradient MRI technique to electronic spins in nitrogen-vacancy (NV) centers in diamond and achieve nanometric resolution in imaging, characterization, and manipulation of individual spins. For NV centers, our results in individual spin control demonstrate an improvement of nearly two orders of magnitude in spatial resolution compared to conventional optical diffraction-limited techniques. This scanning-field-gradient microscope enables a wide range of applications including materials characterization, spin entanglement, and nanoscale magnetometry.

  3. Magnetic resonance imaging of live freshwater mussels (Unionidae)

    USGS Publications Warehouse

    Michael, Holliman F.; Davis, D.; Bogan, A.E.; Kwak, T.J.; Gregory, Cope W.; Levine, J.F.

    2008-01-01

    We examined the soft tissues of live freshwater mussels, Eastern elliptio Elliptio complanata, via magnetic resonance imaging (MRI), acquiring data with a widely available human whole-body MRI system. Anatomical features depicted in the profile images included the foot, stomach, intestine, anterior and posterior adductor muscles, and pericardial cavity. Noteworthy observations on soft tissue morphology included a concentration of lipids at the most posterior aspect of the foot, the presence of hemolymph-filled fissures in the posterior adductor muscle, the presence of a relatively large hemolymph-filled sinus adjacent to the posterior adductor muscle (at the ventral-anterior aspect), and segmentation of the intestine (a diagnostic description not reported previously in Unionidae). Relatively little is known about the basic biology and ecological physiology of freshwater mussels. Traditional approaches for studying anatomy and tissue processes, and for measuring sub-lethal physiological stress, are destructive or invasive. Our study, the first to evaluate freshwater mussel soft tissues by MRI, clarifies the body plan of unionid mussels and demonstrates the efficacy of this technology for in vivo evaluation of the structure, function, and integrity of mussel soft tissues. ?? 2008, The American Microscopical Society, Inc.

  4. Magnetic resonance imaging of the female pelvis: initial experience

    SciTech Connect

    Hricak, H.; Alpers, C.; Crooks, L.E.; Sheldon, P.E.

    1983-12-01

    The potential of magnetic resonance imaging (MRI) was evaluated in 21 female subjects: seven volunteers, 12 patients scanned for reasons unrelated to the lower genitourinary tract, and two patients referred with gynecologic disease. The uterus at several stages was examined; the premenarcheal uterus (one patient), the uterus of reproductive age (12 patients), the postmenopausal uterus (two patients), and in an 8 week pregnancy (one patient). The myometrium and cyclic endometrium in the reproductive age separated by a low-intensity line (probably stratum basale), which allows recognition of changes in thickness of the cyclic endometrium during the menstrual cycle. The corpus uteri can be distinguished from the cervix by the transitional zone of the isthmus. The anatomic relation of the uterus to bladder and rectum is easily outlined. The vagina can be distinguished from the cervix, and the anatomic display of the closely apposed bladder, vagina, and rectum is clear on axial and coronal images. The ovary is identified; the signal intensity from the ovary depends on the acquisition parameter used. Uterine leiomyoma, endometriosis, and dermoid cyst were depicted, but further experience is needed to ascertain the specificity of the findings.

  5. Imaging the pain of low back pain: functional magnetic resonance imaging in combination with monitoring subjective pain perception

    E-print Network

    Apkarian, A. Vania

    Imaging the pain of low back pain: functional magnetic resonance imaging in combination with monitoring subjective pain perception allows the study of clinical pain states A. Vania Apkariana,*, Beth R December 2000 Abstract Most brain imaging studies of pain are done using a two-state subtraction design

  6. Functional assessment of transplanted kidneys with magnetic resonance imaging

    PubMed Central

    Wang, Yu-Ting; Li, Ying-Chun; Yin, Long-Lin; Pu, Hong; Chen, Jia-Yuan

    2015-01-01

    Kidney transplantation has emerged as the treatment of choice for many patients with end-stage renal disease, which is a significant cause of morbidity and mortality. Given the shortage of clinically available donor kidneys and the significant incidence of allograft dysfunction, a noninvasive and accurate assessment of the allograft renal function is critical for postoperative management. Prompt diagnosis of graft dysfunction facilitates clinical intervention of kidneys with salvageable function. New advances in magnetic resonance imaging (MRI) technology have enabled the calculation of various renal parameters that were previously not feasible to measure noninvasively. Diffusion-weighted imaging provides information on renal diffusion and perfusion simultaneously, with quantification by the apparent diffusion coefficient, the decrease of which reflects renal function impairment. Diffusion-tensor imaging accounts for the directionality of molecular motion and measures fractional anisotropy of the kidneys. Blood oxygen level-dependent MR evaluates intrarenal oxygen bioavailability, generating the parameter of R2* (reflecting the concentration of deoxyhemoglobin). A decrease in R2* could happen during acute rejection. MR nephro-urography/renography demonstrates structural data depicting urinary tract obstructions and functional data regarding the glomerular filtration and blood flow. MR angiography details the transplant vasculature and is particularly suitable for detecting vascular complications, with good correlation with digital subtraction angiography. Other functional MRI technologies, such as arterial spin labeling and MR spectroscopy, are showing additional promise. This review highlights MRI as a comprehensive modality to diagnose a variety of etiologies of graft dysfunction, including prerenal (e.g., renal vasculature), renal (intrinsic causes) and postrenal (e.g., obstruction of the collecting system) etiologies. PMID:26516431

  7. Magnetic Resonance Imaging Features of Adenosis in the Breast

    PubMed Central

    Gity, Masoumeh; Arabkheradmand, Ali; Shakiba, Madjid; Khademi, Yassaman; Bijan, Bijan; Sadaghiani, Mohammad Salehi; Jalali, Amir Hossein

    2015-01-01

    Purpose Adenosis lesions of the breast, including sclerosing adenosis and adenosis tumors, are a group of benign proliferative disorders that may mimic the features of malignancy on imaging. In this study, we aim to describe the features of breast adenosis lesions with suspicious or borderline findings on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Methods In our database, we identified 49 pathologically proven breast adenosis lesions for which the final assessment of the breast MRI report was classified as either category 4 (n=45) or category 5 (n=4), according to the Breast Imaging Reporting and Data System (BI-RADS) published by the American College of Radiology (ACR). The lesions had a final diagnosis of either pure adenosis (n=33, 67.3%) or mixed adenosis associated with other benign pathologies (n=16, 32.7%). Results Of the 49 adenosis lesions detected on DCE-MRI, 32 (65.3%) appeared as enhancing masses, 16 (32.7%) as nonmass enhancements, and one (2.1%) as a tiny enhancing focus. Analysis of the enhancing masses based on the ACR BI-RADS lexicon revealed that among the mass descriptors, the most common features were irregular shape in 12 (37.5%), noncircumscribed margin in 20 (62.5%), heterogeneous internal pattern in 16 (50.0%), rapid initial enhancement in 32 (100.0%), and wash-out delayed en-hancement pattern in 21 (65.6%). Of the 16 nonmass enhancing lesions, the most common descriptors included focal distribution in seven (43.8%), segmental distribution in six (37.5%), clumped internal pattern in nine (56.3%), rapid initial enhancement in 16 (100.0%), and wash-out delayed enhancement pattern in eight (50.0%). Conclusion Adenosis lesions of the breast may appear suspicious on breast MRI. Awareness of these suspi-cious-appearing features would be helpful in obviating unnecessary breast biopsies. PMID:26155296

  8. Magnetic Resonance Imaging Characteristics of Ovarian Clear Cell Carcinoma

    PubMed Central

    Wang, Wei; Ding, Jianhui; Zhu, Xiaoli; Li, Yuan; Gu, Yajia; Peng, Weijun

    2015-01-01

    Purpose To probe the magnetic resonance imaging (MRI) features of ovarian clear cell carcinoma (OCCC). Methods This study retrospectively collected MRI data for 21 pathology-confirmed OCCCs from 19 female patients. The MRI findings were analyzed to determine the tumor size, shape/edge, shape and number of protrusions within the cyst, cystic or necrotic components, signal intensity (SI) and enhancement features. Results The age of the 19 patients ranged from 28 to 63 years (mean age: 53 years). Unilateral tumors were found in 17 patients (17/19, 89%); the average size of all tumors was 10.8 cm. The tumors on MRI were classified into two categories: (a) “cystic adnexal mass with solid protrusions” in 12 (57%) and (b) “solid adnexal mass with cystic areas or necrosis” in 9 (43%). For group a, high to very high SI was observed for most tumors (10/12, 83%) on T1-weighted images (T1WIs), and very high SI was observed on T2-weighted images (T2WIs) for all 12 tumors. Most solid protrusions were irregular and few in number and exhibited heterogeneous intermediate SI on T1WIs and T2WIs and prolonged enhanced SI in the contrast study. All 9 OCCCs in group b were predominantly solid masses with unequally sized necrotic or cystic areas in which some cysts were located at the periphery of the tumor (4/9, 44%). The solid components in all 9 tumors showed iso- or slightly high SI on T1WIs, heterogeneous iso-high SI on T2WIs and heterogeneous prolonged enhancement. According to FIGO classification, 14 tumors (14/19, 74%) were stages I-II, and 5 (5/19, 26%) were stages III-IV. Conclusions On MRI, OCCCs present as large unilateral multilocular or unilocular cystic masses with irregular intermediate SI solid protrusions or predominantly solid masses with cysts or necrosis at an early FIGO stage. PMID:26161555

  9. Functional assessment of transplanted kidneys with magnetic resonance imaging.

    PubMed

    Wang, Yu-Ting; Li, Ying-Chun; Yin, Long-Lin; Pu, Hong; Chen, Jia-Yuan

    2015-10-28

    Kidney transplantation has emerged as the treatment of choice for many patients with end-stage renal disease, which is a significant cause of morbidity and mortality. Given the shortage of clinically available donor kidneys and the significant incidence of allograft dysfunction, a noninvasive and accurate assessment of the allograft renal function is critical for postoperative management. Prompt diagnosis of graft dysfunction facilitates clinical intervention of kidneys with salvageable function. New advances in magnetic resonance imaging (MRI) technology have enabled the calculation of various renal parameters that were previously not feasible to measure noninvasively. Diffusion-weighted imaging provides information on renal diffusion and perfusion simultaneously, with quantification by the apparent diffusion coefficient, the decrease of which reflects renal function impairment. Diffusion-tensor imaging accounts for the directionality of molecular motion and measures fractional anisotropy of the kidneys. Blood oxygen level-dependent MR evaluates intrarenal oxygen bioavailability, generating the parameter of R2* (reflecting the concentration of deoxyhemoglobin). A decrease in R2* could happen during acute rejection. MR nephro-urography/renography demonstrates structural data depicting urinary tract obstructions and functional data regarding the glomerular filtration and blood flow. MR angiography details the transplant vasculature and is particularly suitable for detecting vascular complications, with good correlation with digital subtraction angiography. Other functional MRI technologies, such as arterial spin labeling and MR spectroscopy, are showing additional promise. This review highlights MRI as a comprehensive modality to diagnose a variety of etiologies of graft dysfunction, including prerenal (e.g., renal vasculature), renal (intrinsic causes) and postrenal (e.g., obstruction of the collecting system) etiologies. PMID:26516431

  10. Non-rigid image registration of brain magnetic resonance images using Ronald W.K. So , Tommy W.H. Tang, Albert C.S. Chung

    E-print Network

    Chung, Albert C. S.

    Non-rigid image registration of brain magnetic resonance images using graph-cuts Ronald W.K. So à magnetic resonance images. In this paper, the non-rigid medical image registration problem is reformulated, Tommy W.H. Tang, Albert C.S. Chung Lo Kwee-Seong Medical Image Analysis Laboratory, Department

  11. Fahr disease: use of susceptibility-weighted imaging for diagnostic dilemma with magnetic resonance imaging

    PubMed Central

    Solak, Aynur; Genc, Berhan; Kulu, Ugur

    2015-01-01

    Fahr disease (FD) is a well-defined rare neurodegenerative disease that is characterized by idiopathic bilateral symmetric extensive striopallidodentate calcifications. The patients may present with diverse manifestations, most commonly movement disorder, cognitive impairment, and ataxia. Computed tomography (CT) is considered to be critical for accurate diagnosis because it is difficult to reliably identify calcifications by routine magnetic resonance imaging (MRI). Susceptibility-weighted imaging (SWI) is a relatively new 3D gradient-echo (GE) MR sequence with special phase and magnitude processing. SWI phase images can recognize calcifications definitively with higher sensitivity compared to other MRI sequences. In this article, we present two cases of FD with different manifestations and neuroimaging in different age groups and genders, which were diagnosed by SWI and confirmed with CT, and we discuss the contribution of SWI in the diagnosis of FD. In conclusion, we suggest integrating SWI with MRI protocol to identify calcifications in suspicion of neurodegenerative disorders. PMID:26435928

  12. Fetal Brain Magnetic Resonance Imaging Findings In Congenital Cytomegalovirus Infection With Postnatal Imaging Correlation.

    PubMed

    Averill, Lauren W; Kandula, Vinay V R; Akyol, Yakup; Epelman, Monica

    2015-12-01

    Fetal brain magnetic resonance imaging (MRI) is a powerful tool in the diagnosis of symptomatic congenital cytomegalovirus infection, requiring a detailed search for specific features. A combination of anterior temporal lobe abnormalities, white matter lesions, and polymicrogyria is especially predictive. Fetal MRI may provide a unique opportunity to detect anterior temporal cysts and occipital horn septations, as dilation of these areas may decrease later in development. Cortical migration abnormalities, white matter abnormalities, cerebellar dysplasia, and periventricular calcifications are often better depicted on postnatal imaging but can also be detected on fetal MRI. We present the prenatal brain MRI findings seen in congenital cytomegalovirus infection and provide postnatal imaging correlation, highlighting the evolution of findings at different times in prenatal and postnatal developments. PMID:26614131

  13. FRPRCS-8 University of Patras, Patras, Greece, July 16-18, 2007 MAGNETIC RESONANCE IMAGING OF CONCRETE WITH FRP

    E-print Network

    Burgoyne, Chris

    FRPRCS-8 University of Patras, Patras, Greece, July 16-18, 2007 1 MAGNETIC RESONANCE IMAGING of Cambridge, UK Keywords: aramid FRP, magnetic resonance imaging. 1 INTRODUCTION Engineers have long wanted on density differences in the sample, and Magnetic Resonance Imaging, which can locate water within a sample

  14. Detectability of early brain meningitis with magnetic resonance imaging

    SciTech Connect

    Runge, V.M.; Wells, J.W.; Williams, N.M.

    1995-08-01

    The ability of high-field (1.5 T) magnetic resonance imaging (MRI) to detect early brain meningitis was evaluated in a canine model. Contrast dose, timing postinjection, and imaging technique (specifically the use of magnetization transfer) were assessed. Imaging of five canines was performed at 1.5 T 24 hours after injection of Cowans staphylococcus into the cisterna magna. Two control animals also were imaged using the same protocol. Contrast doses of 0.1, 0.3, and 0.8 mmol/kg gadoteridol were compared. Scans were performed at 2, 13, and 22 minutes after an initial injection of 0.1 mmol/kg. Thirty minutes after the initial injection of contrast, a supplemental dose of 0.2 mmol/kg was given. Scans were then repeated at 2, 12, and 22 minutes after this dose was administered. A second supplemental contrast injection of 0.5 mmol/kg was given at 70 minutes, and immediate postinjection scans with and without MT were acquired. Results. In the animals receiving a cisternal injection of bacteria, the degree of meningeal enhancement was greatest at 0.8 mmol/kg, intermediate at 0.3 mmol/kg, and least at 0.1 mmol/kg. Scans in control studies did not demonstrate abnormal meningeal enhancement. High-contrast dose, MT, and acquisition of immediate postcontrast scans all resulted in statistically significant improvement. On masked film review, abnormal meningeal enhancement was noted in only 2 of 5 experimental dogs at a dose of 0.1 mmol/kg (regardless of the use of MT) compared with all animals at a dose of 0.3 mmol/kg. In 18 of 37 dogs (paired scans with and without MT), when abnormal enhancement was noted, the use of MT improved the visualization of abnormal meningeal enhancement. In early brain meningitis, high-contrast dose (0.3 mmol/kg), MT, and scanning immediately after injection improve detection of abnormal meningeal enhancement, thus facilitating the diagnosis of meningitis. Of these factors, contrast dose is the most important. 14 refs., 9 figs., 2 tabs.

  15. Resting-state functional magnetic resonance imaging: review of neurosurgical applications.

    PubMed

    Lang, Stefan; Duncan, Niall; Northoff, Georg

    2014-05-01

    Recent research in brain imaging has highlighted the role of different neural networks in the resting state (ie, no task) in which the brain displays spontaneous low-frequency neuronal oscillations. These can be indirectly measured with resting-state functional magnetic resonance imaging, and functional connectivity can be inferred as the spatiotemporal correlations of this signal. This technique has proliferated in recent years and has allowed the noninvasive investigation of large-scale, distributed functional networks. In this review, we give a brief overview of resting-state networks and examine the use of resting-state functional magnetic resonance imaging in neurosurgical contexts, specifically with respect to neurooncology, epilepsy surgery, and deep brain stimulation. We discuss the advantages and disadvantages compared with task-based functional magnetic resonance imaging, the limitations of resting-state functional magnetic resonance imaging, and the emerging directions of this relatively new technology. PMID:24492661

  16. Magnetic resonance imaging of bilirubin encephalopathy: current limitations and future promise.

    PubMed

    Wisnowski, Jessica L; Panigrahy, Ashok; Painter, Michael J; Watchko, Jon F

    2014-11-01

    Infants with chronic bilirubin encephalopathy often demonstrate abnormal bilateral, symmetric, high-signal intensity on T2-weighted magnetic resonance imaging of the globus pallidus and subthalamic nucleus, consistent with the neuropathology of kernicterus. Early magnetic resonance imaging of at-risk infants, while frequently showing increased T1-signal in these regions, may give false-positive findings due to the presence of myelin in these structures. Advanced magnetic resonance imaging including diffusion-weighted imaging, magnetic resonance spectroscopy, and diffusion tensor imaging with tractography may shed new insights into the pathogenesis of bilirubin-induced brain injury and the neural basis of long-term disability in infants and children with chronic bilirubin encephalopathy. PMID:25267277

  17. SQUID-Detected Magnetic Resonance Imaging in MicroteslaFields

    SciTech Connect

    Moessle, Michael; Hatridge, Michael; Clarke, John

    2006-08-14

    Magnetic resonance imaging (MRI) has developed into a powerful clinical tool for imaging the human body (1). This technique is based on nuclear magnetic resonance (NMR) of protons (2, 3) in a static magnetic field B{sub 0}. An applied radiofrequency pulse causes the protons to precess about B{sub 0} at their Larmor frequency {nu}{sub 0} = ({gamma}/2{pi})B{sub 0}, where {gamma} is the gyromagnetic ratio; {gamma}/2{pi} = 42.58 MHz/tesla. The precessing protons generate an oscillating magnetic field and hence a voltage in a nearby coil that is amplified and recorded. The application of three-dimensional magnetic field gradients specifies a unique magnetic field and thus an NMR frequency in each voxel of the subject, so that with appropriate encoding of the signals one can acquire a complete image (4). Most clinical MRI systems involve magnetic fields generated by superconducting magnets, and the current trend is to higher magnetic fields than the widely used 1.5-T systems (5). Nonetheless, there is ongoing interest in the development of less expensive imagers operating at lower fields. Commercially available 0.2-T systems based on permanent magnets offer both lower cost and a more open access than their higher-field counterparts, at the expense of signal-to-noise-ratio (SNR) and spatial resolution. At the still lower field of 0.03 mT maintained by a conventional, room-temperature solenoid, Connolly and co-workers (6, 7) obtain good spatial resolution and signal-to-noise ratio (SNR) by prepolarizing the protons in a field B{sub p} of 0.3 T. Prepolarization (8) enhances the magnetic moment of an ensemble of protons over that produced by the lower precession field; after the polarizing field is removed, the higher magnetic moment produces a correspondingly larger signal during its precession in B{sub 0}. Using the same method, Stepisnik et al. (9) obtained MR images in the Earth's magnetic field ({approx} 50 {micro}T). Alternatively, one can enhance the signal amplitude in MRI using laser polarized noble gases such as {sup 3}He or {sup 129}Xe (10-12). Hyperpolarized gases were used successfully to image the human lung in fields on the order of several mT (13-15). To overcome the sensitivity loss of Faraday detection at low frequencies, ultrasensitive magnetometers based on the Superconducting QUantum Interference Device (SQUID) (16) are used to detect NMR and MRI signals (17-24). Recently, SQUID-based MRI systems capable of acquiring in vivo images have appeared. For example, in the 10-mT system of Seton et al. (18) signals are coupled to a SQUID via a superconducting tuned circuit, while Clarke and coworkers (22, 25, 26) developed a system at 132 {micro}T with an untuned input circuit coupled to a SQUID. In a quite different approach, atomic magnetometers have been used recently to detect the magnetization (27) and NMR signal (28) of hyperpolarized gases. This technique could potentially be used for low-field MRI in the future. The goal of this review is to summarize the current state-of-the-art of MRI in microtesla fields detected with SQUIDs. The principles of SQUIDs and NMR are briefly reviewed. We show that very narrow NMR linewidths can be achieved in low magnetic fields that are quite inhomogeneous, with illustrative examples from spectroscopy. After describing our ultralow-field MRI system, we present a variety of images. We demonstrate that in microtesla fields the longitudinal relaxation T{sub 1} is much more material dependent than is the case in high fields; this results in a substantial improvement in 'T{sub 1}-weighted contrast imaging'. After outlining the first attempts to combine microtesla NMR with magnetoencephalography (MEG) (29), we conclude with a discussion of future directions.

  18. High-resolution imaging and spectroscopy of multipolar plasmonic resonances in aluminum nanoantennas.

    PubMed

    Martin, Jérôme; Kociak, Mathieu; Mahfoud, Zackaria; Proust, Julien; Gérard, Davy; Plain, Jérôme

    2014-10-01

    We report on the high resolution imaging of multipolar plasmonic resonances in aluminum nanoantennas using electron energy loss spectroscopy (EELS). Plasmonic resonances ranging from near-infrared to ultraviolet (UV) are measured. The spatial distributions of the multipolar resonant modes are mapped and their energy dispersion is retrieved. The losses in the aluminum antennas are studied through the full width at half-maximum of the resonances, unveiling the weight of both interband and radiative damping mechanisms of the different multipolar resonances. In the blue-UV spectral range, high order resonant modes present a quality factor up to 8, two times higher than low order resonant modes at the same energy. This study demonstrates that near-infrared to ultraviolet tunable multipolar plasmonic resonances in aluminum nanoantennas with relatively high quality factors can be engineered. Aluminum nanoantennas are thus an appealing alternative to gold or silver ones in the visible and can be efficiently used for UV plasmonics. PMID:25207386

  19. Imaging tooth enamel using zero echo time (ZTE) magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Rychert, Kevin M.; Zhu, Gang; Kmiec, Maciej M.; Nemani, Venkata K.; Williams, Benjamin B.; Flood, Ann B.; Swartz, Harold M.; Gimi, Barjor

    2015-03-01

    In an event where many thousands of people may have been exposed to levels of radiation that are sufficient to cause the acute radiation syndrome, we need technology that can estimate the absorbed dose on an individual basis for triage and meaningful medical decision making. Such dose estimates may be achieved using in vivo electron paramagnetic resonance (EPR) tooth biodosimetry, which measures the number of persistent free radicals that are generated in tooth enamel following irradiation. However, the accuracy of dose estimates may be impacted by individual variations in teeth, especially the amount and distribution of enamel in the inhomogeneous sensitive volume of the resonator used to detect the radicals. In order to study the relationship between interpersonal variations in enamel and EPR-based dose estimates, it is desirable to estimate these parameters nondestructively and without adding radiation to the teeth. Magnetic Resonance Imaging (MRI) is capable of acquiring structural and biochemical information without imparting additional radiation, which may be beneficial for many EPR dosimetry studies. However, the extremely short T2 relaxation time in tooth structures precludes tooth imaging using conventional MRI methods. Therefore, we used zero echo time (ZTE) MRI to image teeth ex vivo to assess enamel volumes and spatial distributions. Using these data in combination with the data on the distribution of the transverse radio frequency magnetic field from electromagnetic simulations, we then can identify possible sources of variations in radiation-induced signals detectable by EPR. Unlike conventional MRI, ZTE applies spatial encoding gradients during the RF excitation pulse, thereby facilitating signal acquisition almost immediately after excitation, minimizing signal loss from short T2 relaxation times. ZTE successfully provided volumetric measures of tooth enamel that may be related to variations that impact EPR dosimetry and facilitate the development of analytical procedures for individual dose estimates.

  20. Radiation therapy planning and simulation with magnetic resonance images

    NASA Astrophysics Data System (ADS)

    Boettger, Thomas; Nyholm, Tufve; Karlsson, Magnus; Nunna, Chandrasekhar; Celi, Juan Carlos

    2008-03-01

    We present a system which allows for use of magnetic resonance (MR) images as primary RT workflow modality alone and no longer limits the user to computed tomography data for radiation therapy (RT) planning, simulation and patient localization. The single steps for achieving this goal are explained in detail. For planning two MR data sets, MR1 and MR2 are acquired sequentially. For MR1 a standardized Ultrashort TE (UTE) sequence is used enhancing bony anatomy. The sequence for MR2 is chosen to get optimal contrast for the target and the organs at risk for each individual patient. Both images are naturally in registration, neglecting elastic soft tissue deformations. The planning software first automatically extracts skin and bony anatomy from MR1. The user can semi-automatically delineate target structures and organs at risk based on MR1 or MR2, associate all segmentations with MR1 and create a plan in the coordinate system of MR1. Projections similar to digitally reconstructed radiographs (DRR) enhancing bony anatomy are calculated from the MR1 directly and can be used for iso-center definition and setup verification. Furthermore we present a method for creating a Pseudo-CT data set which assigns electron densities to the voxels of MR1 based on the skin and bone segmentations. The Pseudo-CT is then used for dose calculation. Results from first tests under clinical conditions show the feasibility of the completely MR based workflow in RT for necessary clinical cases. It needs to be investigated in how far geometrical distortions influence accuracy of MR-based RT planning.

  1. Intramuscular schwannoma: clinical and magnetic resonance imaging features

    PubMed Central

    Salunke, Abhijeet Ashok; Chen, Yongsheng; Tan, Jun Hao; Chen, Xi; Foo, Tun-Lin; Gartner, Louise Elizabeth; Puhaindran, Mark Edward

    2015-01-01

    INTRODUCTION Schwannomas that arise within the muscle plane are called intramuscular schwannomas. The low incidence of these tumours and the lack of specific clinical features make preoperative diagnosis difficult. Herein, we report our experience with intramuscular schwannomas. We present details of the clinical presentation, radiological diagnosis and management of these tumours. METHODS Between January 2011 and December 2013, 29 patients were diagnosed and treated for histologically proven schwannoma at the National University Hospital, Singapore. Among these 29 patients, eight (five male, three female) had intramuscular schwannomas. RESULTS The mean age of the eight patients was 40 (range 27–57) years. The most common presenting feature was a palpable mass. The mean interval between surgical treatment and the onset of clinical symptoms was 17.1 (range 4–72) months. Six of the eight tumours (75.0%) were located in the lower limb, while 2 (25.0%) were located in the upper limb. None of the patients had any preoperative neurological deficits. Tinel’s sign was present in one patient. Magnetic resonance (MR) imaging showed that the findings of split-fat sign, low signal margin and fascicular sign were present in all patients. The entry and exit sign was observed in 4 (50.0%) patients, a hyperintense rim was observed in 7 (87.5%) patients and the target sign was observed in 5 (62.5%) patients. All patients underwent microsurgical excision of the tumour and none developed any postoperative neurological deficits. CONCLUSION Intramuscular schwannomas demonstrate the findings of split-fat sign, low signal margin and fascicular sign on MR imaging. These findings are useful for the radiological diagnosis of intramuscular schwannoma. PMID:26512147

  2. Magnetic resonance imaging (MRI): A review of genetic damage investigations.

    PubMed

    Vijayalaxmi; Fatahi, Mahsa; Speck, Oliver

    2015-01-01

    Magnetic resonance imaging (MRI) is a powerful, non-invasive diagnostic medical imaging technique widely used to acquire detailed information about anatomy and function of different organs in the body, in both health and disease. It utilizes electromagnetic fields of three different frequency bands: static magnetic field (SMF), time-varying gradient magnetic fields (GMF) in the kHz range and pulsed radiofrequency fields (RF) in the MHz range. There have been some investigations examining the extent of genetic damage following exposure of bacterial and human cells to all three frequency bands of electromagnetic fields, as used during MRI: the rationale for these studies is the well documented evidence of positive correlation between significantly increased genetic damage and carcinogenesis. Overall, the published data were not sufficiently informative and useful because of the small sample size, inappropriate comparison of experimental groups, etc. Besides, when an increased damage was observed in MRI-exposed cells, the fate of such lesions was not further explored from multiple 'down-stream' events. This review provides: (i) information on the basic principles used in MRI technology, (ii) detailed experimental protocols, results and critical comments on the genetic damage investigations thus far conducted using MRI equipment and, (iii) a discussion on several gaps in knowledge in the current scientific literature on MRI. Comprehensive, international, multi-centered collaborative studies, using a common and widely used MRI exposure protocol (cardiac or brain scan) incorporating several genetic/epigenetic damage end-points as well as epidemiological investigations, in large number of individuals/patients are warranted to reduce and perhaps, eliminate uncertainties raised in genetic damage investigations in cells exposed in vitro and in vivo to MRI. PMID:26041266

  3. Clenbuterol Assay by Spectral Imaging Surface Plasmon Resonance Biosensor System.

    PubMed

    Wu, Yichuan; Yao, Manwen; Fang, Xiangyi; Yang, Yucong; Cheng, Xiaoli

    2015-11-01

    To prevent illegal use of clenbuterol and for quality control in the food industry, more efficient and reliable methods for clenbuterol detection are needed. In this study, clenbuterol was detected using a spectral imaging surface plasmon resonance sensor system via two inhibition methods: (1) the target site compensation method, in which anti-clenbuterol antibody was immobilized on the sensor chip as a bioprobe and (2) the solution competition method in which a clenbuterol-BSA conjugate was immobilized on the sensor chip as the bioprobe. The detectable clenbuterol concentration ranged between 6.25 and 100 ?g/mL for both methods. The clenbuterol limit of detection for the target site compensation method and solution competition method are estimated to be 6.7 and 4.5 ?g/mL, respectively. The proposed methods were successfully applied to the detection of clenbuterol molecules and were found to have high specificity and high-throughput and were label free and operationally convenient. PMID:26319570

  4. Ultra-fast parallel magnetic resonance imaging of granular systems

    NASA Astrophysics Data System (ADS)

    Penn, Alexander; Pruessmann, Klaas P.; Müller, Christoph

    2015-03-01

    Several non-intrusive techniques have been applied to probe the dynamics of two-phase granular systems, with the most prominent examples being X-ray tomography, positron emission particle tracking (PEPT), electrical capacitance tomography and magnetic resonance imaging (MRI). MRI comes with the particular advantage that by implementing suitable pulse sequences not only spin densities (i.e. voidage), but also velocity, acceleration, diffusion and chemical reactions can be measured. However, so far the investigation of two-phase granular systems has been performed on relatively small-bore systems (max. diameter 60 mm). Such systems are, however, heavily influenced by wall effects. Furthermore, largely only single-coil detection has been employed, limiting severely the temporal resolution of the data acquisition. Here, we report the acquisition of ultra-fast MRI measurements in large volume vessels using medical MRI scanners. Specifically, parallel MRI, i.e. the simultaneous use of multiple receiver coils, has been exploited to speed up the data acquisition. In combination with advanced pulse sequences, we were able to probe the rapid dynamics (voidage and velocity measurements) of gas-solid systems.

  5. Nanoscale ?-nuclear magnetic resonance depth imaging of topological insulators.

    PubMed

    Koumoulis, Dimitrios; Morris, Gerald D; He, Liang; Kou, Xufeng; King, Danny; Wang, Dong; Hossain, Masrur D; Wang, Kang L; Fiete, Gregory A; Kanatzidis, Mercouri G; Bouchard, Louis-S

    2015-07-14

    Considerable evidence suggests that variations in the properties of topological insulators (TIs) at the nanoscale and at interfaces can strongly affect the physics of topological materials. Therefore, a detailed understanding of surface states and interface coupling is crucial to the search for and applications of new topological phases of matter. Currently, no methods can provide depth profiling near surfaces or at interfaces of topologically inequivalent materials. Such a method could advance the study of interactions. Herein, we present a noninvasive depth-profiling technique based on ?-detected NMR (?-NMR) spectroscopy of radioactive (8)Li(+) ions that can provide "one-dimensional imaging" in films of fixed thickness and generates nanoscale views of the electronic wavefunctions and magnetic order at topological surfaces and interfaces. By mapping the (8)Li nuclear resonance near the surface and 10-nm deep into the bulk of pure and Cr-doped bismuth antimony telluride films, we provide signatures related to the TI properties and their topological nontrivial characteristics that affect the electron-nuclear hyperfine field, the metallic shift, and magnetic order. These nanoscale variations in ?-NMR parameters reflect the unconventional properties of the topological materials under study, and understanding the role of heterogeneities is expected to lead to the discovery of novel phenomena involving quantum materials. PMID:26124141

  6. Mapping social target detection with functional magnetic resonance imaging

    PubMed Central

    Felder, Jennifer N.; Bodfish, James W.; Sikich, Linmarie; Belger, Aysenil

    2009-01-01

    The neural correlates of cognitive control and social processing functions, as well as the characteristic patterns of anomalous brain activation patterns in psychiatric conditions associated with impairment in these functions, have been well characterized. However, these domains have primarily been examined in isolation. The present study used event-related functional magnetic resonance imaging to map brain areas recruited during a target-detection task designed to evaluate responses to both non-social (i.e. shape) and social (i.e. face) target stimuli. Both shape and face targets activated a similar brain network, including the postcentral gyrus, the anterior and posterior cingulate gyri and the right midfrontal gyrus, whereas face targets additionally activated the thalamus, fusiform and temporooccipital cortex, lingual gyrus and paracingulate gyrus. Comparison of activations to social and non-social target events revealed that a small portion of the dorsal anterior cingulate gyrus (Brodmann's area 32) and the supracalcarine cortex were preferentially activated to face targets. These findings indicate that non-social and social stimuli embedded within a cognitive control task activate overlapping and distinct brain regions. Clinical cognitive neuroscience research of disorders characterized by cognitive dysfunction and impaired social processing would benefit from the use of tasks that evaluate the combined effects of deficits in these two domains. PMID:19015088

  7. Sublingual epidermoid cyst presenting with distinctive magnetic resonance imaging findings.

    PubMed

    Yoshida, Naohiro; Kodama, Kozue; Iino, Yukiko

    2014-06-18

    A case of sublingual epidermoid cyst presenting distinctive magnetic resonance imaging (MRI) findings is described. A 39-year-old man presented to our hospital with a three months progressive left submandibular swelling, difficulty moving his tongue, and snoring. Preoperative evaluation with MRI and fine needle aspiration cytology (FNAC) revealed that the heterogeneous cystic lesion contained the squamous cells, which is compatible with ectodermal tissue. The mass was located above the mylohyoid muscle and spread to the pharyngeal space. By considering the size, infection history, patient age, and location, the cyst was completely resected under general anesthesia via cervical approach without any complication. Histopathologically, the cyst wall was lined by stratified squamous epithelium with no skin appendage, suggesting an epidermoid cyst. Ultrasound (US), MRI and FNAC were very useful of the preoperative diagnosis for oral and sublingual lesion. The postoperative course was uneventful and without recurrence after 24 months. This case showed that epidermoid cysts formed the rarely heterogeneous cystic tumor and it underlined usefulness of preoperative diagnosis, such as US, MRI and FNAC for oral and sublingual tumor. PMID:25332766

  8. Observations of field line resonance with global auroral images

    NASA Astrophysics Data System (ADS)

    Liou, K.; Takahashi, K.

    2013-12-01

    We report results from a detailed analysis of an auroral luminosity pulsation event in the Pc 5 range associated with auroral breakup using Polar ultraviolet imager data and magnetic field observations from the ground-based CARISMA magnetometer array and in space by the GOES 8 satellite. It is found that (1) the auroral pulsation appeared predominantly at frequencies around ~0.9 mHz and ~1.8 mHz in the midnight sector centered at the onset (~2100 magnetic local time (MLT)), (2) the longitudinal extent of the auroral pulsation is wider (~12 h in MLT) for the lower-frequency mode and is much narrower for the higher-frequency mode (~3 h in MLT), (3) both auroral and ground magnetic field data show latitudinal wave amplitude and phase shift structures consistent with the field-line resonance (FLR) theory, (4) magnetic field measurements from GOES 8, which was near the onset location, also show two spectral peaks at ~0.9 mHz in the compressional component and at ~2.1 mHz in the poloidal component. It is suggested the observed Pc 5 ULF waves are FLRs produced by the onset-associated magnetic field dipolarization.

  9. Functional magnetic resonance imaging of autism spectrum disorders

    PubMed Central

    Dichter, Gabriel S.

    2012-01-01

    This review presents an overview of functional magnetic resonance imaging findings in autism spectrum disorders (ASDs), Although there is considerable heterogeneity with respect to results across studies, common themes have emerged, including: (i) hypoactivation in nodes of the “social brain” during social processing tasks, including regions within the prefrontal cortex, the posterior superior temporal sulcus, the amygdala, and the fusiform gyrus; (ii) aberrant frontostriatal activation during cognitive control tasks relevant to restricted and repetitive behaviors and interests, including regions within the dorsal prefrontal cortex and the basal ganglia; (iii) differential lateralization and activation of language processing and production regions during communication tasks; (iv) anomalous mesolimbic responses to social and nonsocial rewards; (v) task-based long-range functional hypoconnectivity and short-range hyper-connectivity; and (vi) decreased anterior-posterior functional connectivity during resting states. These findings provide mechanistic accounts of ASD pathophysiology and suggest directions for future research aimed at elucidating etiologic models and developing rationally derived and targeted treatments. PMID:23226956

  10. Magnetic resonance imaging of solvent transport in polymer networks

    SciTech Connect

    Botto, R.E.; Cody, G.D.

    1995-02-01

    The spectroscopic technique of magnetic resonance imaging (MRI) has recently provided a new window into transport of solvents in polymer networks. Diffusion of solvent as a rate-controlling phenomenon is paramount to understanding transport in many important industrial and biological processes, such as upgrading fossil fuels, film casting and coating, development of photoresists, design of drug-delivery systems, development of solvent resistant polymers, etc. By MRI mapping the migration of solvent molecules through various polymer specimens, researchers Robert Botto and George Cody of Argonne National Laboratory, with support from the Division of Chemical Sciences at DOE, were able to characterize and distinguish between different modes of transport behavior associated with fundamentally different types of polymer systems. The method was applied to rubbers, glassy polymers, and coals. In polymers shown to undergo a glass transition from a rigid to rubbery state, a sharply defined solvent front was observed that propagated through specimens in the manner of a constant velocity shock wave. This behavior was contrasted with a smooth solvent concentration gradient found in polymer systems where no glass transition was observed. The results of this analysis have formed the basis of a new model of anomalous transport in polymeric solids and are helping to ascertain fundamental information on the molecular architectures of these materials.

  11. Achromatic synesthesias - a functional magnetic resonance imaging study.

    PubMed

    Melero, H; Ríos-Lago, M; Peña-Melián, A; Álvarez-Linera, J

    2014-09-01

    Grapheme-color synesthetes experience consistent, automatic and idiosyncratic colors associated with specific letters and numbers. Frequently, these specific associations exhibit achromatic synesthetic qualities (e.g. white, black or gray). In this study, we have investigated for the first time the neural basis of achromatic synesthesias, their relationship to chromatic synesthesias and the achromatic congruency effect in order to understand not only synesthetic color but also other components of the synesthetic experience. To achieve this aim, functional magnetic resonance imaging experiments were performed in a group of associator grapheme-color synesthetes and matched controls who were stimulated with real chromatic and achromatic stimuli (Mondrians), and with letters and numbers that elicited different types of grapheme-color synesthesias (i.e. chromatic and achromatic inducers which elicited chromatic but also achromatic synesthesias, as well as congruent and incongruent ones). The information derived from the analysis of Mondrians and chromatic/achromatic synesthesias suggests that real and synesthetic colors/achromaticity do not fully share neural mechanisms. The whole-brain analysis of BOLD signals in response to the complete set of synesthetic inducers revealed that the functional peculiarities of the synesthetic brain are distributed, and reflect different components of the synesthetic experience: a perceptual component, an (attentional) feature binding component, and an emotional component. Additionally, the inclusion of achromatic experiences has provided new evidence in favor of the emotional binding theory, a line of interpretation which constitutes a bridge between grapheme-color synesthesia and other developmental modalities of the phenomenon. PMID:24845620

  12. Microwave near-field imaging of electric fields in a superconducting microstrip resonator

    E-print Network

    Anlage, Steven

    Microwave near-field imaging of electric fields in a superconducting microstrip resonator Ashfaq S describe the use of a cryogenic near-field scanning microwave microscope to image microwave electric fields of about 200 m. We describe the operation of the system and present microwave images of Cu and Tl2Ba2CaCu2O

  13. Unwarping confocal microscopy images of bee brains by nonrigid registration to a magnetic resonance

    E-print Network

    Menzel, Randolf - Institut für Biologie

    Unwarping confocal microscopy images of bee brains by nonrigid registration to a magnetic resonance microscopy image Torsten Rohlfing SRI International Neuroscience Program 333 Ravenswood Avenue Menlo Park Abstract. Confocal microscopy (CM) is a powerful image acquisition technique that is well established

  14. Wavelets and statistical analysis of functional magnetic resonance images of the human brain

    E-print Network

    Breakspear, Michael

    Wavelets and statistical analysis of functional magnetic resonance images of the human brain Ed. Wavelets are particularly well suited to analysis of biological signals and images, such as human brain Bullmore Brain Mapping Unit and Wolfson Brain Imaging Centre, University of Cambridge, Addenbrooke

  15. Imaging hypothalamic activity using diffusion weighted magnetic resonance imaging in the mouse and human brain.

    PubMed

    Lizarbe, Blanca; Benítez, Ania; Sánchez-Montañés, Manuel; Lago-Fernández, Luis F; Garcia-Martin, María L; López-Larrubia, Pilar; Cerdán, Sebastián

    2013-01-01

    Hypothalamic appetite regulation is a vital homeostatic process underlying global energy balance in animals and humans, its disturbances resulting in feeding disorders with high morbidity and mortality. The objective evaluation of appetite remains difficult, very often restricted to indirect measurements of food intake and body weight. We report here, the direct, non-invasive visualization of hypothalamic activation by fasting using diffusion weighted magnetic resonance imaging, in the mouse brain as well as in a preliminary study in the human brain. The brain of fed or fasted mice or humans were imaged at 7 or 1.5 Tesla, respectively, by diffusion weighted magnetic resonance imaging using a complete range of b values (10image data sets were registered and analyzed pixel by pixel using a biexponential model of diffusion, or a model-free Linear Discriminant Analysis approach. Biexponential fittings revealed statistically significant increases in the slow diffusion parameters of the model, consistent with a neurocellular swelling response in the fasted hypothalamus. Increased resolution approaches allowed the detection of increases in the diffusion parameters within the Arcuate Nucleus, Ventromedial Nucleus and Dorsomedial Nucleus. Independently, Linear Discriminant Analysis was able to classify successfully the diffusion data sets from mice and humans between fed and fasted states. Present results are consistent with increased glutamatergic neurotransmission during orexigenic firing, a process resulting in increased ionic accumulation and concomitant osmotic neurocellular swelling. This swelling response is spatially extendable through surrounding astrocytic networks until it becomes MRI detectable. Present findings open new avenues for the direct, non-invasive, evaluation of appetite disorders and other hypothalamic pathologies helping potentially in the development of the corresponding therapies. PMID:23000787

  16. Multi circular-cavity surface coil for magnetic resonance imaging of monkey's brain at 4 Tesla

    NASA Astrophysics Data System (ADS)

    Osorio, A. I.; Solis-Najera, S. E.; Vázquez, F.; Wang, R. L.; Tomasi, D.; Rodriguez, A. O.

    2014-11-01

    Animal models in medical research has been used to study humans diseases for several decades. The use of different imaging techniques together with different animal models offers a great advantage due to the possibility to study some human pathologies without the necessity of chirurgical intervention. The employ of magnetic resonance imaging for the acquisition of anatomical and functional images is an excellent tool because its noninvasive nature. Dedicated coils to perform magnetic resonance imaging experiments are obligatory due to the improvement on the signal-to-noise ratio and reduced specific absorption ratio. A specifically designed surface coil for magnetic resonance imaging of monkey's brain is proposed based on the multi circular-slot coil. Numerical simulations of the magnetic and electric fields were also performed using the Finite Integration Method to solve Maxwell's equations for this particular coil design and, to study the behavior of various vector magnetic field configurations and specific absorption ratio. Monkey's brain images were then acquired with a research-dedicated magnetic resonance imaging system at 4T, to evaluate the anatomical images with conventional imaging sequences. This coil showed good quality images of a monkey's brain and full compatibility with standard pulse sequences implemented in research-dedicated imager.

  17. Magnetic resonance imaging for adaptive cobalt tomotherapy: A proposal

    PubMed Central

    Kron, Tomas; Eyles, David; John, Schreiner L; Battista, Jerry

    2006-01-01

    Magnetic resonance imaging (MRI) provides excellent soft tissue contrast for oncology applications. We propose to combine a MRI scanner with a helical tomotherapy (HT) system to enable daily target imaging for improved conformal radiation dose delivery to a patient. HT uses an intensity-modulated fan-beam that revolves around a patient, while the patient slowly advances through the plane of rotation, yielding a helical beam trajectory. Since the use of a linear accelerator to produce radiation may be incompatible with the pulsed radiofrequency and the high and pulsed magnetic fields required for MRI, it is proposed that a radioactive Cobalt-60 (60Co) source be used instead to provide the radiation. An open low field (0.25 T) MRI system is proposed where the tomotherapy ring gantry is located between two sets of Helmholtz coils that can generate a sufficiently homogenous main magnetic field. It is shown that the two major challenges with the design, namely acceptable radiation dose rate (and therefore treatment duration) and moving parts in strong magnetic field, can be addressed. The high dose rate desired for helical tomotherapy delivery can be achieved using two radiation sources of 220TBq (6000Ci) each on a ring gantry with a source to axis-of-rotation distance of 75 cm. In addition to this, a dual row multi-leaf collimator (MLC) system with 15 mm leaf width at isocentre and relatively large fan beam widths between 15 and 30 mm per row shall be employed. In this configuration, the unit would be well-suited for most pelvic radiotherapy applications where the soft tissue contrast of MRI will be particularly beneficial. Non-magnetic MRI compatible materials must be used for the rotating gantry. Tungsten, which is non-magnetic, can be used for primary collimation of the fan-beam as well as for the MLC, which allows intensity modulated radiation delivery. We propose to employ a low magnetic Cobalt compound, sycoporite (CoS) for the Cobalt source material itself. Rotational delivery is less susceptible to problems related to the use of a low energy megavoltage photon source while the helical delivery reduces the negative impact of the relatively large penumbra inherent in the use of Cobalt sources for radiotherapy. On the other hand, the use of a 60Co source ensures constant dose rate with gantry rotation and makes dose calculation in a magnetic field as easy as the range of secondary electrons is limited. The MR-integrated Cobalt tomotherapy unit, dubbed ‘MiCoTo,’ uses two independent physical principles for image acquisition and treatment delivery. It would offer excellent target definition and will allow following target motion during treatment using fast imaging techniques thus providing the best possible input for adaptive radiotherapy. As an additional bonus, quality assurance of the radiation delivery can be performed in situ using radiation sensitive gels imaged by MRI. PMID:21206640

  18. Magnetic resonance imaging appropriate for construction of subject-specific head models for diffuse optical tomography

    PubMed Central

    Kurihara, Kazuki; Kawaguchi, Hiroshi; Obata, Takayuki; Ito, Hiroshi; Okada, Eiji

    2015-01-01

    Subject-specific head models of which their geometry is based on structural magnetic resonance images are essential to accurately estimate the spatial sensitivity profiles for image reconstruction in diffuse optical tomography. T1-weighted magnetic resonance images, which are commonly used for structural imaging, are not sufficient for the threshold-based segmentation of the superficial tissues. Two types of pulse sequences, which provide a high contrast among the superficial tissues, are introduced to complement the segmentation to construct the subject-specific head models. The magnetic resonance images acquired by the proposed pulse sequences are robust to the threshold level and adequate for the threshold-based segmentation of the superficial tissues compared to the T1- and T2-weighted images. The total scan time of the proposed pulse sequences is less than one-fourth of that for the T2-weighted pulse sequence. PMID:26417492

  19. Visual Presentation of Magnetic Resonance Images J. E. van der Heyden, M. S. T. Carpendale, K. Inkpen, M. S. Atkins

    E-print Network

    Carpendale, Sheelagh

    Visual Presentation of Magnetic Resonance Images J. E. van der Heyden, M. S. T. Carpendale, K that involve viewing and analyzing large sets of images on a computer screen. Magnetic Resonance Imaging (MRI. Inkpen, M. S. Atkins School of Computing Science Simon Fraser University 1. ABSTRACT Medical image

  20. Imaging of stroke: a comparison between X-ray fluorescence and magnetic resonance imaging methods

    PubMed Central

    Zheng, Weili; Haacke, E. Mark; Webb, Samuel M.; Nichol, Helen

    2013-01-01

    A dual imaging approach, combining magnetic resonance imaging to localize lesions and synchrotron rapid scanning X-ray fluorescence (XRF) mapping to localize and quantify calcium, iron and zinc was used to examine one case of recent stroke with hemorrhage and two cases of ischemia 3 and 7 years before death with the latter showing superficial necrosis. In hemorrhagic lesions, more Fe is found accompanied with less Zn. In chronic ischemic lesions, Fe, Zn and Ca are lower indicating that these elements are removed as the normal tissue dies and scar tissue forms. Both susceptibility and T2* maps were calculated to visualize iron in hemorrhages and validated by XRF Ca and Fe maps. The former was superior for imaging iron in hemorrhagic transformation and necrosis but did not capture ischemic lesions. In contrast, T2* could not differentiate Ca from Fe in necrotic tissue but did capture ischemic lesions, complementing the susceptibility mapping. The spatial localization, accurate quantitative data and elemental differentiation shown here could also be valuable for imaging other brain tissue damage with abnormal Ca and Fe content. PMID:22789844

  1. Brain functional magnetic resonance imaging response to glucose and fructose infusions in humans

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Objective: In animals, intracerebroventricular glucose and fructose have opposing effects on appetite and weight regulation. In humans, functional brain magnetic resonance imaging (fMRI) studies during carbohydrate ingestion suggest that glucose may regulate HT signaling but are potentially confoun...

  2. A 16-Channel Receive Array Insert for Magnetic Resonance Imaging of the Breast at 7T 

    E-print Network

    By, Samantha

    2014-04-01

    Breast cancer is the second leading cause of cancer death among females in the United States. Magnetic resonance imaging (MRI) has emerged as a powerful tool for detecting and evaluating the disease, with notable advantages over other modalities...

  3. Anatomical Brain Magnetic Resonance Imaging of Typically Developing Children and Adolescents

    ERIC Educational Resources Information Center

    Giedd, Jay N.; Lalonde, Francois M.; Celano, Mark J.; White, Samantha L.; Wallace, Gregory L.; Lee, Nancy R.; Lenroot, Rhoshel K.

    2009-01-01

    Methodological issues relevant to magnetic resonance imaging studies of brain anatomy are discussed along with the findings on the neuroanatomic changes during childhood and adolescence. The development of the brain is also discussed.

  4. Genetic contributions to cognitive ageing and structural brain magnetic resonance imaging phenotypes 

    E-print Network

    Lyall, Donald

    2013-11-29

    detailed assessment that also included detailed brain magnetic resonance imaging (N range = 700-866). I investigated the independent effects of two linked genetic loci which have been associated with greater risk of Alzheimer’s disease – the APOE ?...

  5. A new presentation method for magnetic resonance angiography images based on skeletonization

    E-print Network

    Nyström, Ingela

    A new presentation method for magnetic resonance angiography images based on skeletonization Ingela that uses skeletonization and distance transformations, which visualizes variations in vessel width independent of viewing direction. In the skeletonization, the object is reduced to a surface skeleton

  6. Local-feature-based similarity measure for stochastic resonance in visual perception of spatially structured images.

    PubMed

    Delahaies, Agnès; Rousseau, David; Fasquel, Jean-Baptiste; Chapeau-Blondeau, François

    2012-07-01

    For images, stochastic resonance or useful-noise effects have previously been assessed with low-level pixel-based information measures. Such measures are not sensitive to coherent spatial structures usually existing in images. As a result, we show that such measures are not sufficient to properly account for stochastic resonance occurring in visual perception. We introduce higher-level similarity measures, inspired from visual perception, and based on local feature descriptors of scale invariant feature transform (SIFT) type. We demonstrate that such SIFT-based measures allow for an assessment of stochastic resonance that matches the visual perception of images with spatial structures. Constructive action of noise is registered in this way with both additive noise and multiplicative speckle noise. Speckle noise, with its grainy appearance, is particularly prone to introducing spurious spatial structures in images, and the stochastic resonance visually perceived and quantitatively assessed with SIFT-based measures is specially examined in this context. PMID:22751385

  7. Multimodal neuroimaging with simultaneous electroencephalogram and high-field functional magnetic resonance imaging

    E-print Network

    Purdon, Patrick L. (Patrick Lee), 1974-

    2005-01-01

    Simultaneous recording of electroencephalogram (EEG) and functional magnetic resonance imaging (tMRI) is an important emerging tool in functional neuroimaging with the potential to reveal new mechanisms for brain function ...

  8. Cardiac dysfunction in the diabetic rat: quantitative evaluation using high resolution magnetic resonance imaging

    E-print Network

    Loganathan, Rajprasad; Bilgen, Mehmet; Al-Hafez, Baraa; Alenezy, Mohammed D.; Smirnova, Irina V.

    2006-04-04

    . The functional abnormalities of diabetic myocardium have been attributed to the pathological changes of diabetic cardiomyopathy. Methods: In this study, we used high field magnetic resonance imaging (MRI) to evaluate the left ventricular functional...

  9. Highly Parallel Magnetic Resonance Imaging with a Fourth Gradient Channel for Compensation of RF Phase Patterns 

    E-print Network

    Bosshard, John 1983-

    2012-08-20

    A fourth gradient channel was implemented to provide slice dependent RF coil phase compensation for arrays in dual-sided or "sandwich" configurations. The use of highly parallel arrays for single echo acquisition magnetic resonance imaging allows...

  10. Accelerated parallel magnetic resonance imaging reconstruction using joint estimation with a sparse signal model

    E-print Network

    Weller, Daniel S.

    Accelerating magnetic resonance imaging (MRI) by reducing the number of acquired k-space scan lines benefits conventional MRI significantly by decreasing the time subjects remain in the magnet. In this paper, we formulate ...

  11. Eight-Channel Head Array and Control System for Parallel Transmit/Receive Magnetic Resonance Imaging 

    E-print Network

    Moody, Katherine

    2014-08-11

    Interest in magnetic resonance imaging (MRI) at high fields strengths (3 Tesla and above) is driven by the associated improvements in signal-to-noise ratio and spectral resolution. In practice, however, technical challenges prevent these benefits...

  12. Nuclear magnetic resonance imaging and analysis for determination of porous media properties 

    E-print Network

    Uh, Jinsoo

    2007-04-25

    Advanced nuclear magnetic resonance (NMR) imaging methodologies have been developed to determine porous media properties associated with fluid flow processes. This dissertation presents the development of NMR experimental and analysis methodologies...

  13. Phase-based regional oxygen metabolism in magnetic resonance imaging at high field

    E-print Network

    Fan, Audrey Peiwen

    2010-01-01

    Venous oxygen saturation (Yv) in cerebral veins and the cerebral metabolic rate of oxygen (CMRO?) are important indicators for brain function and disease. Phase-susceptibility measurements in magnetic resonance imaging ...

  14. HST.583 Functional Magnetic Resonance Imaging: Data Acquisition and Analysis, Fall 2006

    E-print Network

    Gollub, Randy L.

    This team taught, multidisciplinary course covers the fundamentals of magnetic resonance imaging relevant to the conduct and interpretation of human brain mapping studies. The challenges inherent in advancing our knowledge ...

  15. Semantic feature distinctiveness: A functional magnetic resonance imaging (fMRI) study Megan Reilly1

    E-print Network

    Semantic feature distinctiveness: A functional magnetic resonance imaging (fMRI) study Megan Reilly functions and multiple subdivisions. The Neuroscientist , 19(1), 43-61. Contact: Megan Reilly, megan

  16. Magnetic resonance spectroscopic imaging with 2D spectroscopy for the detection of brain metabolites

    E-print Network

    Kok, Trina

    2012-01-01

    While magnetic resonance imaging (MRI) derives its signal from protons in water, additional biochemical compounds are detectable in vivo within the proton spectrum. The detection and mapping of these much weaker signals ...

  17. Accelerating magnetic resonance imaging by unifying sparse models and multiple receivers

    E-print Network

    Weller, Daniel (Daniel Stuart)

    2012-01-01

    Magnetic resonance imaging (MRI) is an increasingly versatile diagnostic tool for a variety of medical purposes. During a conventional MRI scan, samples are acquired along a trajectory in the spatial Fourier transform ...

  18. Transmit field pattern control for high field magnetic resonance imaging with integrated RF current sources 

    E-print Network

    Kurpad, Krishna Nagaraj

    2005-11-01

    The primary design criterion for RF transmit coils for MRI is uniform transverse magnetic (B1) field. Currently, most high frequency transmit coils are designed as periodic, symmetric structures that are resonant at the imaging frequency...

  19. Automatic design tool for robust radio frequency decoupling matrices in magnetic resonance imaging

    E-print Network

    Mahmood, Zohaib

    2015-01-01

    In this thesis we study the design of robust decoupling matrices for coupled transmit radio frequency arrays used in magnetic resonance imaging (MRI). In a coupled parallel transmit array, because of the coupling itself, ...

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

    PubMed Central

    Kukreja, Aastha; Lim, Eun-Kyung; Kang, Byunghoon; Choi, Yuna; Lee, Taeksu; Suh, Jin-Suck; Huh, Yong-Min; Haam, Seungjoo

    2014-01-01

    In this study, dextran-encrusted magnetic nanoclusters (DMNCs) were synthesized using a one-pot solution phase method for detection of atherosclerosis by magnetic resonance imaging. Pyrenyl dextran was used as a surfactant because of its electron-stabilizing effect and its amphiphilic nature, rendering the DMNCs stable and water-dispersible. The DMNCs were 65.6±4.3 nm, had a narrow size distribution, and were superparamagnetic with a high magnetization value of 60.1 emu/g. Further, they showed biocompatibility and high cellular uptake efficiency, as indicated by a strong interaction between dextran and macrophages. In vivo magnetic resonance imaging demonstrated the ability of DMNCs to act as an efficient magnetic resonance imaging contrast agent capable of targeted detection of atherosclerosis. In view of these findings, it is concluded that DMNCs can be used as magnetic resonance imaging contrast agents to detect inflammatory disease. PMID:24904209

  1. A Functional Magnetic Resonance Imaging Predictor of Treatment Response to Venlafaxine in Generalized

    E-print Network

    Reading, University of

    A Functional Magnetic Resonance Imaging Predictor of Treatment Response to Venlafaxine subjects (12 female subjects) with GAD participated in an open-label venlafaxine treatment trial began treatment were compared with changes in anxiety following 8 weeks of venlafaxine administration

  2. Surface Plasmon Resonance Imaging Using a High Numerical Aperture Microscope Objective

    E-print Network

    Zare, Richard N.

    Surface Plasmon Resonance Imaging Using a High Numerical Aperture Microscope Objective Bo Huang-5080 We designed, constructed, and tested a surface plasmon resonance (SPR) microscope using a high, combined with various methods to shorten the surface plasmon propaga- tion length, achieves diffraction

  3. DEPRESSION SYMPTOMS AND COGNITIVE CONTROL OF EMOTION CUES: A FUNCTIONAL MAGNETIC RESONANCE IMAGING STUDY

    E-print Network

    Beevers, Christopher

    DEPRESSION SYMPTOMS AND COGNITIVE CONTROL OF EMOTION CUES: A FUNCTIONAL MAGNETIC RESONANCE IMAGING at Austin, Austin, TX, USA Abstract--Few studies have examined associations between depressive symptoms- erate symptoms of depression and a non-depressed control group while functional magnetic resonance

  4. Investigation of cardiomyopathy using cardiac magnetic resonance imaging part 1: Common phenotypes

    PubMed Central

    McDermott, Shaunagh; O’Neill, Ailbhe C; Ridge, Carole A; Dodd, Jonathan D

    2012-01-01

    Cardiac magnetic resonance imaging (CMRI) has emerged as a useful tertiary imaging tool in the investigation of patients suspected of many different types of cardiomyopathies. CMRI sequences are now of a sufficiently robust quality to enable high spatial and temporal resolution image acquisition. This has led to CMRI becoming an effective non-invasive imaging gold standard for many cardiomyopathies. In this 2-part review, we outline the typical sequences used to image cardiomyopathy, and present the imaging spectrum of cardiomyopathy. Part 1 focuses on the current classification of cardiomyopathy, basic CMRI sequences used in evaluating cardiomyopathy and the imaging spectrum of common phenotypes. PMID:22558489

  5. Can Images Obtained With High Field Strength Magnetic Resonance Imaging Reduce Contouring Variability of the Prostate?

    SciTech Connect

    Usmani, Nawaid; Sloboda, Ron; Kamal, Wafa; Ghosh, Sunita; Pervez, Nadeem; Pedersen, John; Yee, Don; Danielson, Brita; Murtha, Albert; Amanie, John; Monajemi, Tara

    2011-07-01

    Purpose: The objective of this study is to determine whether there is less contouring variability of the prostate using higher-strength magnetic resonance images (MRI) compared with standard MRI and computed tomography (CT). Methods and Materials: Forty patients treated with prostate brachytherapy were accrued to a prospective study that included the acquisition of 1.5-T MR and CT images at specified time points. A subset of 10 patients had additional 3.0-T MR images acquired at the same time as their 1.5-T MR scans. Images from each of these patients were contoured by 5 radiation oncologists, with a random subset of patients repeated to quantify intraobserver contouring variability. To minimize bias in contouring the prostate, the image sets were placed in folders in a random order with all identifiers removed from the images. Results: Although there was less interobserver contouring variability in the overall prostate volumes in 1.5-T MRI compared with 3.0-T MRI (p < 0.01), there was no significant differences in contouring variability in the different regions of the prostate between 1.5-T MRI and 3.0-T MRI. MRI demonstrated significantly less interobserver contouring variability in both 1.5-T and 3.0-T compared with CT in overall prostate volumes (p < 0.01, p = 0.01), with the greatest benefits being appreciated in the base of the prostate. Overall, there was less intraobserver contouring variability than interobserver contouring variability for all of the measurements analyzed. Conclusions: Use of 3.0-T MRI does not demonstrate a significant improvement in contouring variability compared with 1.5-T MRI, although both magnetic strengths demonstrated less contouring variability compared with CT.

  6. ADVANCED MAGNETIC RESONANCE IMAGING OF CEREBRAL CAVERNOUS MALFORMATIONS: I. HIGH FIELD IMAGING OF EXCISED HUMAN LESIONS

    PubMed Central

    Shenkar, Robert; Venkatasubramanian, Palamadai N.; Zhao, Jin-cheng; Batjer, H. Hunt; Wyrwicz, Alice M.; Awad, Issam A.

    2008-01-01

    Objectives We hypothesized that structural details would be revealed in cerebral cavernous malformations (CCMs) through the use of high field magnetic resonance (MR) and confocal microscopy, which have not been described previously. The structural details of CCMs excised from human patients were sought by examination with high field MR imaging, and correlated with confocal microscopy of the same specimens. Novel features of CCM structure are outlined, including methodological limitations, venues for future research and possible clinical implications. Methods CCM lesions excised from four patients were fixed in 2% paraformaldehyde and subjected to high resolution MR imaging at 9.4 or 14.1 Tesla by spin-echo and gradient recalled echo methods. Histological validation of angioarchitecture was conducted on thick sections of CCM lesions using fluorescent probes to endothelium under confocal microscopy. Results Images of excised human CCM lesions were acquired with proton density-weighted, T1-weighted, T2-weighted spin echo and T2*-weighted gradient-recalled echo MR. These images revealed large “bland” regions with thin walled caverns, and “honeycombed” regions with notable capillary proliferation and smaller caverns surrounding larger caverns. Proliferating capillaries and caverns of various sizes were also associated with the wall of apparent larger blood vessels in the lesions. Similar features were confirmed within thick sections of CCMs by confocal microscopy. MR relaxation times in different regions of interest suggested the presence of different states of blood breakdown products in areas with apparent angiogenic proliferative activity. Conclusions The high field MR imaging techniques demonstrate novel features of CCM angioarchitecture, visible at near histological resolution, including regions with apparently different biologic activity. These preliminary observations will motivate future research, correlating lesion biologic and clinical activity with features of MR imaging at higher field strength. PMID:18981890

  7. Developing hyperpolarized krypton-83 for nuclear magnetic resonance spectroscopy and magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Cleveland, Zackary I.

    This dissertation discusses the production of highly nonequilibrium nuclear spin polarization, referred to as hyperpolarization or hp, in the nuclear spin I = 9/2 noble gas isotope krypton-83 using spin exchange optical pumping (SEOP). This nonequilibrium polarization yields nuclear magnetic resonance (NMR) signals that are enhanced three or more orders of magnitude above those of thermally polarized krypton and enables experiments that would otherwise be impossible. Krypton-83 possesses a nuclear electric quadrupole moment that dominates the longitudinal (T1) relaxation due to coupling of the quadrupole moment to fluctuating electric field gradients generated by distortions to the spherical symmetry of the electronic environment. Relaxation slows polarization buildup and limits the maximum signal intensity but makes krypton-83 a sensitive probe of its environment. The gas-phase krypton-83 longitudinal relaxation rate increases linearly with total gas density due to binary collisions. Density independent relaxation, caused by the formation of krypton-krypton van der Waals molecules and surface adsorption, also contributes to the observed rate. Buffer gases suppress van der Waals molecule mediated relaxation by breaking apart the weakly bound krypton dimers. Surface relaxation is gas composition independent and therefore more difficult to suppress. However, this relaxation mechanism makes hp krypton-83 sensitive to important surface properties including surface-to-volume ratio, surface chemistry, and surface temperature. The presence of surfaces with high krypton adsorption affinities (i.e. hydrophobic surfaces) accelerates the relaxation times and can produce T1 contrast in hp krypton-83 magnetic resonance imaging (MRI). Tobacco smoke deposited on surfaces generates strong T1 contrast allowing the observation of smoke deposition with spatial resolution. Conversely, water adsorption on surfaces significantly lengths the T1 times due competitive surface adsorption. Finally, this work demonstrates that hp krypton-83 MRI of intact, excised lungs is feasible. No attempts have been made to observe pathology specific contrast, but this work represents the first steps in developing hp krypton into a useful biomedical tool. Although the signal must be improved for biomedical applications, additional enhancements of up to 180 times greater than the currently obtained signal are possible through improved SEOP, and another order of magnitude increase can be obtained through isotopic enrichment.

  8. Detecting tumor responses to treatment using hyperpolarized 13C magnetic resonance spectroscopic imaging

    E-print Network

    2010-09-24

    Detecting tumor responses to treatment using hyperpolarized 13C magnetic resonance spectroscopic imaging Kevin M Brindle From 16th International Charles Heidelberger Symposium on Cancer Research Coimbra, Portugal. 26–28 September 2010 Patients with similar... , Brindle KM: Detecting tumor response to treatment using hyperpolarized 13C magnetic resonance imaging and spectroscopy. Nat Med 2007, 13:1382-1387. 4. Witney TH, Kettunen MI, Day SE, Hu DE, Neves AA, Gallagher FA, Fulton SM, Brindle KM: A comparison...

  9. Magnetic resonance imaging detected prostate evasive anterior tumours: Further insights

    PubMed Central

    Edwan, Ghazi Al; Ghai, Sangeet; Margel, David; Kulkarni, Girish; Hamilton, Rob; Toi, Ants; Haidar, Masoom A.; Finelli, Antonio; Fleshner, Neil E.

    2015-01-01

    Introduction: Clinical confusion continues to exist regarding the underestimation of cancers among patients on active surveillance and among men with repeated negative prostate biopsies despite worrisome prostate-specific antigen (PSA) levels. We have previously described our initial experience with magnetic resonance imaging (MRI)-based detection of tumours in the anterior prostate gland. In this report, we update and expand our experience with these tumours in terms of multiparametric-MRI findings, staging, and grading. Furthermore, we report early treatment outcomes with these unique cancers. Methods: We reviewed our prostate MRI dataset of 1117 cases from January 2006 until December 2012 and identified 189 patients who fulfilled criteria for prostate evasive anterior tumors (PEATS). Descriptive analyses were performed on multiple covariates. Kaplan-Meier actuarial technique was used to plot the treatment-related outcomes from PEATS tumours. Results: Among the 189 patients who had MRI-detectable anterior tumours, 148 had biopsy proven disease in the anterior zone. Among these tumours, the average PSA was 18.3 ng/mL and most cancers were Gleason 7. In total, 68 patients chose surgical therapy. Among these men, most of their cancers had extra prostatic extension and 46% had positive surgical margins. Interestingly, upgrading of tumours that were biopsy Gleason 6 in the anterior zone was common, with 59% exhibiting upgrading to Gleason 7 or higher. Biochemical-free survival among men who elected surgery was not ideal, with 20% failing by 20 months. Conclusion: PEATS tumours are found late and are disproportionally high grade tumours. Careful consideration to MRI testing should be given to men at risk for PEATS. PMID:26029293

  10. Does Magnetic Resonance Imaging Affect the Microleakage of Amalgam Restorations?

    PubMed Central

    Akgun, Ozlem Marti; Polat, Gunseli Guven; Turan Illca, Ahmet; Yildirim, Ceren; Demir, Pervin; Basak, Feridun

    2014-01-01

    Background: The effect of MRI on microleakage of amalgam restorations is an important health issue that should be considered. If MRI application causes increase of microleakage, amalgam fillings should be reassessed after MRI and replaced if necessary. Objectives: The aim of this study is to compare the effect of magnetic resonance imaging (MRI) on microleakage of class II bonded amalgam versus classical amalgam restorations. Materials and Methods: Class II cavities (3 mm width × 1.5 mm depth) with gingival margins ending 1 mm below the cementoenamel junction (CEJ) were prepared in 40 permanent molar teeth. The teeth were randomly divided into four groups. Cavities in the first and second groups were restored with dentin adhesive and amalgam (bonded amalgam), and those in the third and fourth groups with amalgam only. MRI was performed with the teeth specimens from the first and third groups. All specimens were then thermocycled at 5° to 55° C with a 30-second dwell time for 1000 cycles. The samples were then immersed in 0.5% methylene blue dye for 24 hours and sectioned longitudinally. Dye penetration at the occlusal and gingival margins was quantified by 15× stereomicroscopy. IBM SPSS Statistics ver. 21.0 (IBM Corp., Released 2012., IBM SPSS Statistics for Windows, Armonk, NY: IBM Corp.) and MS-Excel 2007 programs were used for statistical analyses and calculations. “nparLD” module was used for F2_LD_F1 design analysis at R program. P<0.05 was considered statistically significant. Results: In teeth with amalgam filling, there were no significant differences of occlusal and gingival surface microleakage after MRI exposure. Occlusal and gingival surface microleakages were also similar with and without MRI in teeth with bonded amalgam filling. Conclusions: The results of this study suggest that MRI does not increase microleakage of amalgam restorations. PMID:25763074

  11. Diagnostic Accuracy on Magnetic Resonance Imaging for the Diagnosis of Osteoarthritis of the Temporomandibular Joint

    PubMed Central

    Harada, Saori; Kobayashi, Kazuhiko

    2015-01-01

    Objectives Osteoarthritis, which is also called degenerative arthritis or degenerative joint disease, is primarily a disease that results from the breakdown and loss of cartilage in joints. The purpose of this study was to investigate the diagnostic accuracy of magnetic resonance images for the diagnosis of osteoarthritis of the temporomandibular joint. Materials and Methods Fifty patients (50 joints) with closed locking of the temporomandibular joint were examined with magnetic resonance imaging and then underwent arthroscopic surgery. The agreement of osteoarthritis between magnetic resonance images and arthroscopic findings was studied using the ? coefficient. Results The incidence of osteoarthritis on magnetic resonance images (38%) was significantly lower than that in arthroscopic findings (78%). There was no significant agreement between these two findings (p=.108). The ? coefficient was 0.154. Conclusion The diagnostic accuracy of magnetic resonance images for osteoarthritis of the temporomandibular joint was low; early osteoarthritis could not be diagnosed from magnetic resonance images. Clinicians should understand that the diagnostic accuracy of osteoarthritis without arthroscopy is not always high. PMID:26393215

  12. Molecular Imaging of Tumors Using a Quantitative T1 Mapping Technique via Magnetic Resonance Imaging

    PubMed Central

    Herrmann, Kelsey; Johansen, Mette L.; Craig, Sonya E.; Vincent, Jason; Howell, Michael; Gao, Ying; Lu, Lan; Erokwu, Bernadette; Agnes, Richard S.; Lu, Zheng-Rong; Pokorski, Jonathan K.; Basilion, James; Gulani, Vikas; Griswold, Mark; Flask, Chris; Brady-Kalnay, Susann M.

    2015-01-01

    Magnetic resonance imaging (MRI) of glioblastoma multiforme (GBM) with molecular imaging agents would allow for the specific localization of brain tumors. Prior studies using T1-weighted MR imaging demonstrated that the SBK2-Tris-(Gd-DOTA)3 molecular imaging agent labeled heterotopic xenograft models of brain tumors more intensely than non-specific contrast agents using conventional T1-weighted imaging techniques. In this study, we used a dynamic quantitative T1 mapping strategy to more objectively compare intra-tumoral retention of the SBK2-Tris-(Gd-DOTA)3 agent over time in comparison to non-targeted control agents. Our results demonstrate that the targeted SBK2-Tris-(Gd-DOTA)3 agent, a scrambled-Tris-(Gd-DOTA)3 control agent, and the non-specific clinical contrast agent Optimark™ all enhanced flank tumors of human glioma cells with similar maximal changes on T1 mapping. However, the retention of the agents differs. The non-specific agents show significant recovery within 20 min by an increase in T1 while the specific agent SBK2-Tris-(Gd-DOTA)3 is retained in the tumors and shows little recovery over 60 min. The retention effect is demonstrated by percent change in T1 values and slope calculations as well as by calculations of gadolinium concentration in tumor compared to muscle. Quantitative T1 mapping demonstrates the superior binding and retention in tumors of the SBK2-Tris-(Gd-DOTA)3 agent over time compared to the non-specific contrast agent currently in clinical use. PMID:26435847

  13. Magnetic resonance imaging of multiple sclerosis lesions. Measuring outcome in treatment trials.

    PubMed Central

    Simon, J H

    1996-01-01

    Magnetic resonance-based measures of disease activity and progression are now routinely used in definitive phase III treatment trials of multiple sclerosis as important secondary outcome measures because they provide quantitative and objective confirmation of the primary clinical outcome measures. Magnetic resonance-based activity measures can also be used as an efficient mechanism for screening therapies in phase I and II trials. In this review I consider the natural history of multiple sclerosis lesions and the relationships between magnetic resonance measures and clinical observations of disease as the basis for the use of magnetic resonance markers in current and future treatment trials. Images Figure 3. Figure 4. PMID:8764625

  14. Sensitive segmentation of low-contrast multispectral images based on multiparameter space-resonance imaging method

    NASA Astrophysics Data System (ADS)

    Akhmetshin, Alexander M.; Akhmetshin, Lyudmila G.

    2001-10-01

    A new method of low contrast multispectral, hyperspectral and multiparameter images segmentation is outlined. The one has significant advantage in sensitivity and space resolving power of segmentation in comparison with known methods such as principal component transformation and fuzzy C-means clustering segmentation ones. New method is based on using of two important stages: 1) application virtual long-wave holographic transformation to each separate image of analyzed multispectral sequence (it is needed for increasing sensitivity of further analysis); 2) to each pixel of analyzed multispectral image is compare a virtual nonrecursive digital filter with complex coefficients. The one is characterized by its amplitude-frequency (AFC) and phase-frequency (PFC) characteristics. Information features used for visualization and segmentation are frequencies corresponded to maximum (resonance point) or minimum (antiresonance point) of AFC and group delay function calculated on base PFC. Information possibilities of new method are demonstrated on examples of multispectral remote sensing, various physical nature geophysical fields fusion and multiparameter MRI brain tumor hidden area influence detection.

  15. Surface Plasmon Resonance of Nanoparticles and Applications in Imaging

    NASA Astrophysics Data System (ADS)

    Ammari, Habib; Deng, Youjun; Millien, Pierre

    2015-09-01

    In this paper we provide a mathematical framework for localized plasmon resonance of nanoparticles. Using layer potential techniques associated with the full Maxwell equations, we derive small-volume expansions for the electromagnetic fields, which are uniformly valid with respect to the nanoparticle's bulk electron relaxation rate. Then, we discuss the scattering and absorption enhancements by plasmon resonant nanoparticles. We study both the cases of a single and multiple nanoparticles. We present numerical simulations of the localized surface plasmonic resonances associated to multiple particles in terms of their separation distance.

  16. Surface Plasmon Resonance of Nanoparticles and Applications in Imaging

    E-print Network

    Habib Ammari; Youjun Deng; Pierre Millien

    2015-08-04

    In this paper we provide a mathematical framework for localized plasmon resonance of nanoparticles. Using layer potential techniques associated with the full Maxwell equations, we derive small-volume expansions for the electromagnetic fields, which are uniformly valid with respect to the nanoparticle's bulk electron relaxation rate. Then, we discuss the scattering and absorption enhancements by plasmon resonant nanoparticles. We study both the cases of a single and multiple nanoparticles. We present numerical simulations of the localized surface plasmonic resonances associated to multiple particles in terms of their separation distance.

  17. Far-field subwavelength imaging with near-field resonant metalens scanning at microwave frequencies

    PubMed Central

    Wang, Ren; Wang, Bing-Zhong; Gong, Zhi-Shuang; Ding, Xiao

    2015-01-01

    A method for far-field subwavelength imaging at microwave frequencies using near-field resonant metalens scanning is proposed. The resonant metalens is composed of switchable split-ring resonators (SRRs). The on-SRR has a strong magnetic coupling ability and can convert evanescent waves into propagating waves using the localized resonant modes. In contrast, the off-SRR cannot achieve an effective conversion. By changing the switch status of each cell, we can obtain position information regarding the subwavelength source targets from the far field. Because the spatial response and Green’s function do not need to be measured and evaluated and only a narrow frequency band is required for the entire imaging process, this method is convenient and adaptable to various environment. This method can be used for many applications, such as subwavelength imaging, detection, and electromagnetic monitoring, in both free space and complex environments. PMID:26053074

  18. Microwave Dielectric Contrast Imaging in a Magnetic Resonant Environment and the Effect of using Magnetic Resonant Spatial Information in Image Reconstruction

    PubMed Central

    Epstein, Neil R.; Golnabi, Amir H.; Meaney, Paul M.; Paulsen, Keith D.

    2013-01-01

    Microwave Tomography (MT) can determine the permittivity and conductivity of a volume of interest; it has been shown that a contrast exists between these electrical properties in healthy and malignant tissues, and MT can be used to discern the dielectric contrast image of these tissues by recovering their electrical property values. Simulation and phantom experiments of objects with known spatial locations have shown that using boundary information derived from internal structures in the imaged volume greatly increases the accuracy of the recovered property values. In practice this spatial information, which will be used for reconstructing the tissue’s electrical property images, must be determined with high enough resolution to segment boundary regions and internal structures of interest. This experiment investigates the use of Magnetic Resonant Imaging (MRI) in obtaining the desired spatial information used in mesh generation for image reconstruction and provides microwave image results comparing electrical properties recovered with and without this prior spatial information. PMID:22255643

  19. Nuclear magnetic resonance imaging. (Latest citations from the US Patent database). Published Search

    SciTech Connect

    Not Available

    1993-01-01

    The bibliography contains citations of selected patents concerning imaging systems and components used in nuclear magnetic resonance (NMR) devices. Data acquisition methods and applications in fluid flow are presented. Magnet systems used in the imaging process are briefly cited. (Contains a minimum of 159 citations and includes a subject term index and title list.)

  20. Complex-Valued Analysis of Arterial Spin LabelingBased Functional Magnetic Resonance Imaging

    E-print Network

    Rowe, Daniel B.

    Complex-Valued Analysis of Arterial Spin Labeling­Based Functional Magnetic Resonance Imaging-dependent phase differences between tagged and control arterial spin labeling images are reported. A biophysical model is presented to explain the vascular origin of this difference. Arterial spin labeling data

  1. [Cardiac magnetic resonance imaging and cardiac computed tomography in clinical practice].

    PubMed

    Barone-Rochette, G; Jankowski, A; Rodiere, M

    2014-11-01

    Technological advances have enabled the rapid development of cardiovascular imaging techniques. Cardiac computed tomography (CT) and cardiac magnetic resonance imaging (MRI) have become diagnostic and prognostic tools for the management of patients in routine clinical practice. This review gives the main indications and describes the performance of both techniques. PMID:25023720

  2. Magnetic Resonance Imaging–guided Volumetric Ablation of Symptomatic Leiomyomata: Correlation of Imaging with Histology

    PubMed Central

    Venkatesan, Aradhana M.; Partanen, Ari; Pulanic, Tajana Klepac; Dreher, Matthew R.; Fischer, John; Zurawin, Robert K.; Muthupillai, Raja; Sokka, Sham; Nieminen, Heikki J.; Sinaii, Ninet; Merino, Maria; Wood, Bradford J.; Stratton, Pamela

    2012-01-01

    Purpose To describe the preliminary safety and accuracy of a magnetic resonance (MR) imaging– guided high-intensity–focused ultrasound (HIFU) system employing new technical developments, including ablation control via volumetric thermal feedback, for the treatment of uterine leiomyomata with histopathologic correlation. Materials and Methods In this phase I clinical trial, 11 women underwent MR-guided HIFU ablation (Sonalleve 1.5T; Philips Medical Systems, Vantaa, Finland), followed by hysterectomy within 30 days. Adverse events, imaging findings, and pathologic confirmation of ablation were assessed. The relationship between MR imaging findings, thermal dose estimates, and pathology and HIFU spatial accuracy were assessed using Bland-Altman analyses and intraclass correlations. Results There were 12 leiomyomata treated. No serious adverse events were observed. Two subjects decided against having hysterectomy and withdrew from the study before surgery. Of 11 women, 9 underwent hysterectomy; all leiomyomata demonstrated treatment in the expected location. A mean ablation volume of 6.92 cm3 ± 10.7 was observed at histopathologic examination. No significant differences between MR imaging nonperfused volumes, thermal dose estimates, and histopathology ablation volumes were observed (P > .05). Mean misregistration values perpendicular to the ultrasound beam axis were 0.8 mm ± 1.2 in feet-head direction and 0.1 mm ± 1.0 in and left-right direction and ?0.7 mm ± 3.1 along the axis. Conclusions Safe, accurate ablation of uterine leiomyomata was achieved with an MR-guided HIFU system with novel treatment monitoring capabilities, including ablation control via volumetric thermal feedback. PMID:22626269

  3. Superconducting Microwave Resonator Arrays for Submillimeter/Far-Infrared Imaging

    NASA Astrophysics Data System (ADS)

    Noroozian, Omid

    Superconducting microwave resonators have the potential to revolutionize submillimeter and far-infrared astronomy, and with it our understanding of the universe. The field of low-temperature detector technology has reached a point where extremely sensitive devices like transition-edge sensors are now capable of detecting radiation limited by the background noise of the universe. However, the size of these detector arrays are limited to only a few thousand pixels. This is because of the cost and complexity of fabricating large-scale arrays of these detectors that can reach up to 10 lithographic levels on chip, and the complicated SQUID-based multiplexing circuitry and wiring for readout of each detector. In order to make substantial progress, next-generation ground-based telescopes such as CCAT or future space telescopes require focal planes with large-scale detector arrays of 104--10 6 pixels. Arrays using microwave kinetic inductance detectors (MKID) are a potential solution. These arrays can be easily made with a single layer of superconducting metal film deposited on a silicon substrate and pattered using conventional optical lithography. Furthermore, MKIDs are inherently multiplexable in the frequency domain, allowing ˜ 10 3 detectors to be read out using a single coaxial transmission line and cryogenic amplifier, drastically reducing cost and complexity. An MKID uses the change in the microwave surface impedance of a superconducting thin-film microresonator to detect photons. Absorption of photons in the superconductor breaks Cooper pairs into quasiparticles, changing the complex surface impedance, which results in a perturbation of resonator frequency and quality factor. For excitation and readout, the resonator is weakly coupled to a transmission line. The complex amplitude of a microwave probe signal tuned on-resonance and transmitted on the feedline past the resonator is perturbed as photons are absorbed in the superconductor. The perturbation can be detected using a cryogenic amplifier and subsequent homodyne mixing at room temperature. In an array of MKIDs, all the resonators are coupled to a shared feedline and are tuned to slightly different frequencies. They can be read out simultaneously using a comb of frequencies generated and measured using digital techniques. This thesis documents an effort to demonstrate the basic operation of ˜ 256 pixel arrays of lumped-element MKIDs made from superconducting TiN x on silicon. The resonators are designed and simulated for optimum operation. Various properties of the resonators and arrays are measured and compared to theoretical expectations. A particularly exciting observation is the extremely high quality factors (˜ 3 x 107) of our TiNx resonators which is essential for ultra-high sensitivity. The arrays are tightly packed both in space and in frequency which is desirable for larger full-size arrays. However, this can cause a serious problem in terms of microwave crosstalk between neighboring pixels. We show that by properly designing the resonator geometry, crosstalk can be eliminated; this is supported by our measurement results. We also tackle the problem of excess frequency noise in MKIDs. Intrinsic noise in the form of an excess resonance frequency jitter exists in planar superconducting resonators that are made on dielectric substrates. We conclusively show that this noise is due to fluctuations of the resonator capacitance. In turn, the capacitance fluctuations are thought to be driven by two-level system (TLS) fluctuators in a thin layer on the surface of the device. With a modified resonator design we demonstrate with measurements that this noise can be substantially reduced. An optimized version of this resonator was designed for the multiwavelength submillimeter kinetic inductance camera (MUSIC) instrument for the Caltech Submillimeter Observatory.

  4. Functional Magnetic Resonance Imaging and Spectroscopic Imaging of the Brain: Application of fMRI and fMRS to Reading Disabilities and Education.

    ERIC Educational Resources Information Center

    Richards, Todd L.

    2001-01-01

    This tutorial/review covers functional brain-imaging methods and results used to study language and reading disabilities. Although the emphasis is on magnetic resonance imaging and functional magnetic resonance spectroscopy, other imaging techniques are also discussed including positron emission tomography, electroencephalography,…

  5. Signal- and contrast-to-noise in fast magnetic resonance imaging: Expectation and reality

    SciTech Connect

    Tkach, J.A.

    1988-01-01

    Steady state free precession (SFP) magnetic resonance (MR) techniques had their origins in MR spectroscopy over thirty years ago. However, they were not successfully applied to magnetic resonance imaging until several years ago. The purpose of this study was twofold: (1) to examine, in depth, the signal and contrast behavior of the partial flip angle techniques FLASH and FISP as a function of tissue and experimental parameters and (2) to investigate their potential role in clinical imaging (head imaging in particular). Tissue properties similar to those encountered in the head at 1T were selected.

  6. A novel radio frequency coil for veterinary magnetic resonance imaging system

    NASA Astrophysics Data System (ADS)

    Meng, Bin; Huang, Kai-Wen; Wang, Wei-Min

    2010-07-01

    In this article, a novel designed radio frequency (RF) coil is designed and built for the imaging of puppies in a V-shape permanent magnetic resonance imaging (MRI) system. Two sets of Helmholtz coil pairs with a V-shape structure are used to improve the holding of an animal in the coil. The homogeneity and the sensitivity of the RF field in the coil are analysed by theoretical calculation. The size and the shape of the new coil are optimized and validated by simulation through using the finite element method (FEM). Good magnetic resonance (MR) images are achieved on a shepherd dog.

  7. Wavelet smoothing of functional magnetic resonance images: A ...

    E-print Network

    1910-30-72

    Various statistical tests can be used to determine these activation regions. .... is often used to color fMRI volume images, so on the bottom half of each image .... A theory of wavelet decompositions for data that have different smoothness ...

  8. [Magnetic resonance imaging for lumbar disk pathology. incidence of false negatives].

    PubMed

    Berthelot, J M; Maugars, Y; Delecrin, J; Caillon, F; Prost, A

    1995-10-01

    Magnetic resonance imaging (MRI) has had an impressive impact on evaluation of degenerative diseases of the spine. Nevertheless, false negatives can occur on images involving lumbar discs. Degenerative disc diseases documented on discrography and/or pathology examination of the discs can go unrecognized. Likewise sensitivity for the detection of protruding discal hernias is not totally satisfactory (20% false negatives). Finally, a magnetic resonance image visualizing displacement of the disc is not specific (10 to 15% false positives); images showing protrusion or hernia can be seen in 30% of asymptomatic patients. Although MRI gives slightly more information than other imaging techniques, false images do exist. Moreover, the usefulness of MRI to demonstrate disc disease in case of a negative CT-scan remains to be demonstrated. PMID:7494842

  9. 1. INTRODUCTION Functional Magnetic Resonance Imaging (fMRI) is a rapidly developing tool that enables cognitive

    E-print Network

    Genovese, Christopher

    1. INTRODUCTION Functional Magnetic Resonance Imaging (fMRI) is a rapidly developing tool Resonance (MR) images of the subject's brain are acquired at regular intervals. The tasks are designed voxels. The MR signal for a voxel in a single image is related to the transverse magnetization

  10. Novel Imaging Contrast Methods for Hyperpolarized 13 C Magnetic Resonance Imaging

    NASA Astrophysics Data System (ADS)

    Reed, Galen Durant

    Magnetic resonance imaging using hyperpolarized 13C-labeled small molecules has emerged as an extremely powerful tool for the in vivo monitoring of perfusion and metabolism. This work presents methods for improved imaging, parameter mapping, and image contrast generation for in vivo hyperpolarized 13C MRI. Angiography using hyperpolarized urea was greatly improved with a highly T2-weighted acquisition in combination with 15N labeling of the urea amide groups. This is due to the fact that the T2 of [13C]urea is strongly limited by the scalar coupling to the neighboring quadrupolar 14N. The long in vivo T2 values of [13C, 15N2]urea were utilized for sub-millimeter projection angiography using a contrast agent that could be safely injected in concentrations of 10-100 mM while still tolerated in patients with renal insufficiency. This study also presented the first method for in vivo T2 mapping of hyperpolarized 13C compounds. The in vivo T2 of urea was short in the blood and long within the kidneys. This persistent signal component was isolated to the renal filtrate, thus enabling for the first time direct detection of an imaging contrast agent undergoing glomerular filtration. While highly T2-weighted acquisitions select for molecules with short rotational correlation times, high diffusion weighting selects for those with the long translational correlation times. A specialized spin-echo EPI sequence was developed in order to generate highly diffusion-weighted hyperpolarized 13C images on a clinical MRI system operating within clinical peak- RF and gradient amplitude constraints. Low power adiabatic spin echo pulses were developed in order to generate a sufficiently large refocused bandwidth while maintaining low nominal power. This diffusion weighted acquisition gave enhanced tumor contrast-to-noise ratio when imaging [1-13C]lactate after infusion of [1-13C]pyruvate. Finally, the first in-man hyperpolarized 13C MRI clinical trial is discussed.

  11. Acoustic subwavelength imaging of subsurface objects with acoustic resonant metalens

    SciTech Connect

    Cheng, Ying; Liu, XiaoJun; State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190 ; Zhou, Chen; Wei, Qi; Wu, DaJian

    2013-11-25

    Early research into acoustic metamaterials has shown the possibility of achieving subwavelength near-field acoustic imaging. However, a major restriction of acoustic metamaterials is that the imaging objects must be placed in close vicinity of the devices. Here, we present an approach for acoustic imaging of subsurface objects far below the diffraction limit. An acoustic metalens made of holey-structured metamaterials is used to magnify evanescent waves, which can rebuild an image at the central plane. Without changing the physical structure of the metalens, our proposed approach can image objects located at certain distances from the input surface, which provides subsurface signatures of the objects with subwavelength spatial resolution.

  12. Magnetic Resonance Imaging of a Liver Hydatid Cyst Invading the Portal Vein and Causing Portal Cavernomatosis

    PubMed Central

    Herek, Duygu; Sungurtekin, Ugur

    2015-01-01

    Background Hepatic hydatid cysts rarely invade portal veins causing portal cavernomatosis as a secondary complication. Case Report We report the case of a patient with direct invasion of the right portal vein by hydatid cysts causing portal cavernomatosis diagnosed via magnetic resonance imaging (MRI). Conclusion The presented case highlights the useful application of MRI with T2-weighted images and gadolinium-enhanced T1-weighted images in the diagnosis of hepatic hydatid lesions presenting with a rare complication of portal cavernomatosis.

  13. Intraventricular mass lesions at magnetic resonance imaging: iconographic essay - part 2*

    PubMed Central

    de Castro, Felipe Damásio; Reis, Fabiano; Guerra, José Guilherme Giocondo

    2014-01-01

    The present essay is illustrated with magnetic resonance images obtained at the authors' institution over the past 15 years and discusses the main imaging findings of intraventricular tumor-like lesions (colloid cyst, oligodendroglioma, astroblastoma, lipoma, cavernoma) and of inflammatory/infectious lesions (neurocysticercosis and an atypical presentation of neurohistoplasmosis). Such lesions represent a subgroup of intracranial lesions with unique characteristics and some imaging patterns that may facilitate the differential diagnosis. PMID:25741092

  14. Image-based control of the magnetic resonance imaging-guided focused ultrasound thermotherapy.

    PubMed

    Salomir, Rares; Delemazure, Anne-Sophie; Palussière, Jean; Rouvière, Olivier; Cotton, François; Chapelon, Jean-Yves

    2006-06-01

    Magnetic resonance imaging (MRI)-guided focused ultrasound surgery (FUS) is a full noninvasive approach for localized thermal ablation of deep tissues, coupling the following: (1) a versatile, nonionizing physical agent for therapy and (2) a state-of-the art diagnosis and on-line monitoring tool. A commercially available, Food and Drug Administration-approved device using the MRI-guided FUS exists since 2004 for the ablation of benign tumors (uterine fibroids); however, the ultimate goal of the technological, methodological, and medical research in this field is to provide a clinical-routine tool for fighting localized cancer. When addressing cancer applications, the accurate spatial control of the delivered thermal dose is mandatory. Contiguous destruction of the target volume must be achieved in a minimum time, whereas sparing as much as possible the neighboring healthy tissues and especially when some adjacent regions are critical. This paper reviews some significant developments reported in the literature related to the image-based control of the FUS therapy for kidney, breast, prostate, and brain, including the own experience of the authors on the active feedback control of the temperature during FUS ablation. In addition, preliminary results of an original study of MRI-guided FUS ablation of VX2 carcinoma in kidney, under active temperature control, are described here. PMID:17414071

  15. Terahertz Pulsed Imaging and Magnetic Resonance Imaging as Tools to Probe Formulation Stability

    PubMed Central

    Zhang, Qilei; Gladden, Lynn F.; Avalle, Paolo; Zeitler, J. Axel; Mantle, Michael D.

    2013-01-01

    Dissolution stability over the entire shelf life duration is of critical importance to ensure the quality of solid dosage forms. Changes in the drug release profile during storage may affect the bioavailability of drug products. This study investigated the stability of a commercial tablet (Lescol® XL) when stored under accelerated conditions (40 °C/75% r.h.). Terahertz pulsed imaging (TPI) was used to investigate the structure of the tablet coating before and after the accelerated aging process. The results indicate that the coating was reduced in thickness and exhibited a higher density after being stored under accelerated conditions for four weeks. In situ magnetic resonance imaging (MRI) of the water penetration processes during tablet dissolution in a USP-IV dissolution cell equipped with an in-line UV-vis analyzer was carried out to study local differences in water uptake into the tablet matrix between the stressed and unstressed state. The drug release profiles of the Lescol® XL tablet before and after the accelerated storage stability testing were compared using a “difference” factor f1 and a “similarity” factor f2. The results reveal that even though the physical properties of the coating layers changed significantly during the stress testing, the coating protected the tablet matrix and the densification of the coating polymer had no adverse effect on the drug release performance. PMID:24300564

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

    PubMed Central

    Fiorelli, Marco; Aceti, Franca; Marini, Isabella; Giacchetti, Nicoletta; Macci, Enrica; Tinelli, Emanuele; Calistri, Valentina; Meuti, Valentina; Caramia, Francesca; Biondi, Massimo

    2015-01-01

    Postpartum depression is a frequent and disabling condition whose pathophysiology is still unclear. In recent years, the study of the neural correlates of mental disorders has been increasingly approached using magnetic resonance techniques. In this review we synthesize the results from studies on postpartum depression in the context of structural, functional, and spectroscopic magnetic resonance studies of major depression as a whole. Compared to the relative wealth of data available for major depression, magnetic resonance studies of postpartum depression are limited in number and design. A systematic literature search yielded only eleven studies conducted on about one hundred mothers with postpartum depression overall. Brain magnetic resonance findings in postpartum depression appear to replicate those obtained in major depression, with minor deviations that are not sufficient to delineate a distinct neurobiological profile for this condition, due to the small samples used and the lack of direct comparisons with subjects with major depression. However, it seems reasonable to expect that studies conducted in larger populations, and using a larger variety of brain magnetic resonance techniques than has been done so far, might allow for the identification of neuroimaging signatures for postpartum depression. PMID:26347585

  17. Diffusion tensor imaging using a high-temperature superconducting resonator in a 3 T magnetic resonance imaging for a spontaneous rat brain tumor

    NASA Astrophysics Data System (ADS)

    Lin, In-Tsang; Yang, Hong-Chang; Chen, Jyh-Horng

    2013-02-01

    This study investigates the peri-tumor signal abnormalities of a spontaneous brain tumor in a rat by using a 4 cm high-temperature superconducting (HTS) surface resonator. Fractional anisotropy (FA) values derived from diffusion tensor imaging reflect the interstitial characteristic of the peri-lesional tissues of brain tumors. Low FA indicates interstitial tumor infiltration and tissue injury, while high FA indicates better tissue integrity. Better delineation of tissue contents obtained by the HTS surface resonator at 77 K may facilitate therapeutic strategy and improve clinical outcomes.

  18. Dual-Enzyme-Loaded Multifunctional Hybrid Nanogel System for Pathological Responsive Ultrasound Imaging and T2-Weighted Magnetic Resonance Imaging.

    PubMed

    Wang, Xia; Niu, Dechao; Li, Pei; Wu, Qing; Bo, Xiaowan; Liu, Boji; Bao, Song; Su, Teng; Xu, Huixiong; Wang, Qigang

    2015-06-23

    A dual-enzyme-loaded multifunctional hybrid nanogel probe (SPIO@GCS/acryl/biotin-CAT/SOD-gel, or SGC) has been developed for dual-modality pathological responsive ultrasound (US) imaging and enhanced T2-weighted magnetic resonance (MR) imaging. This probe is composed of functionalized superparamagnetic iron oxide particles, a dual enzyme species (catalase and superoxide dismutase), and a polysaccharide cationic polymer glycol chitosan gel. The dual-modality US/MR imaging capabilities of the hybrid nanogel for responsive US imaging and enhanced T2-weighted MR imaging have been evaluated both in vitro and in vivo. These results show that the hybrid nanogel SGC can exhibit efficient dual-enzyme biocatalysis with pathological species for responsive US imaging. SGC also demonstrates increased accumulation in acidic environments for enhanced T2-weighted MR imaging. Further research on these nanogel systems may lead to the development of more efficient US/MR contrast agents. PMID:26035730

  19. Quantitative Determination of Lateral Mode Dispersion in Film Bulk Acoustic Resonators through Laser Acoustic Imaging

    SciTech Connect

    Ken Telschow; John D. Larson III

    2006-10-01

    Film Bulk Acoustic Resonators are useful for many signal processing applications. Detailed knowledge of their operation properties are needed to optimize their design for specific applications. The finite size of these resonators precludes their use in single acoustic modes; rather, multiple wave modes, such as, lateral wave modes are always excited concurrently. In order to determine the contributions of these modes, we have been using a newly developed full-field laser acoustic imaging approach to directly measure their amplitude and phase throughout the resonator. This paper describes new results comparing modeling of both elastic and piezoelectric effects in the active material with imaging measurement of all excited modes. Fourier transformation of the acoustic amplitude and phase displacement images provides a quantitative determination of excited mode amplitude and wavenumber at any frequency. Images combined at several frequencies form a direct visualization of lateral mode excitation and dispersion for the device under test allowing mode identification and comparison with predicted operational properties. Discussion and analysis are presented for modes near the first longitudinal thickness resonance (~900 MHz) in an AlN thin film resonator. Plate wave modeling, taking account of material crystalline orientation, elastic and piezoelectric properties and overlayer metallic films, will be discussed in relation to direct image measurements.

  20. Making Sense of Real-Time Functional Magnetic Resonance Imaging (rtfMRI) and rtfMRI Neurofeedback

    PubMed Central

    2015-01-01

    This review explains the mechanism of functional magnetic resonance imaging in general and specifically introduces real-time functional magnetic resonance imaging as a method for training self-regulation of brain activity. Using real-time functional magnetic resonance imaging neurofeedback, participants can acquire control over their own brain activity. In patients with neuropsychiatric disorders, this control can potentially have therapeutic implications. In this review, the technical requirements are presented and potential applications and limitations are discussed. PMID:25716778