Science.gov

Sample records for resonance imaging detected

  1. 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.

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

    PubMed Central

    Sinharay, Sanhita; Pagel, Mark D.

    2016-01-01

    Recent advances in magnetic resonance imaging (MRI) contrast agents have provided new capabilities for biomarker detection through molecular imaging. MRI contrast agents based on the T2 exchange mechanism have more recently expanded the armamentarium of agents for molecular imaging. Compared with T1 and T2* agents, T2 exchange agents have a slower chemical exchange rate, which improves the ability to design these MRI contrast agents with greater specificity for detecting the intended biomarker. MRI contrast agents that are detected through chemical exchange saturation transfer (CEST) have even slower chemical exchange rates. Another emerging class of MRI contrast agents uses hyperpolarized 13C to detect the agent with outstanding sensitivity. These hyperpolarized 13C agents can be used to track metabolism and monitor characteristics of the tissue microenvironment. Together, these various MRI contrast agents provide excellent opportunities to develop molecular imaging for biomarker detection. PMID:27049630

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

    PubMed

    Sinharay, Sanhita; Pagel, Mark D

    2016-06-12

    Recent advances in magnetic resonance imaging (MRI) contrast agents have provided new capabilities for biomarker detection through molecular imaging. MRI contrast agents based on the T2 exchange mechanism have more recently expanded the armamentarium of agents for molecular imaging. Compared with T1 and T2* agents, T2 exchange agents have a slower chemical exchange rate, which improves the ability to design these MRI contrast agents with greater specificity for detecting the intended biomarker. MRI contrast agents that are detected through chemical exchange saturation transfer (CEST) have even slower chemical exchange rates. Another emerging class of MRI contrast agents uses hyperpolarized (13)C to detect the agent with outstanding sensitivity. These hyperpolarized (13)C agents can be used to track metabolism and monitor characteristics of the tissue microenvironment. Together, these various MRI contrast agents provide excellent opportunities to develop molecular imaging for biomarker detection. PMID:27049630

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

    NASA Astrophysics Data System (ADS)

    Sinharay, Sanhita; Pagel, Mark D.

    2016-06-01

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

  5. 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.

  6. Ultrasensitive magnetometry and magnetic resonance imaging using cantilever detection

    NASA Astrophysics Data System (ADS)

    Rugar, Daniel

    2009-03-01

    Micromachined cantilevers make remarkable magnetometers for nanoscale measurements of magnetic materials and for magnetic resonance imaging (MRI). We present various applications of cantilever magnetometry at low temperature using cantilevers capable of attonewton force sensitivity. Small, unexpected magnetic effects can be seen, such as anomalous damping in magnetic field. A key application is magnetic resonance force microscopy (MRFM) of both electron and nuclear spins. In recent experiments with MRFM-based NMR imaging, 3D spatial resolution better than 10 nm was achieved for protons in individual virus particles. The achieved volumetric resolution represents an improvement of 100 million compared to the best conventional MRI. The microscope is sensitive enough to detect NMR signals from adsorbed layers of hydrocarbon contamination, hydrogen in multiwall carbon nanotubes and the phosphorus in DNA. Operating with a force noise on the order of 6 aN per root hertz with a magnetic tip that produces a field gradient in excess of 30 gauss per nanometer, the magnetic moment sensitivity is ˜0.2 Bohr magnetons. The corresponding field sensitivity is ˜3 nT per root hertz. To our knowledge, this combination of high field sensitivity and nanometer spatial resolution is unsurpassed by any other form of nanometer-scale magnetometry.

  7. Management of breast magnetic resonance imaging-detected lesions.

    PubMed

    Seely, Jean M

    2012-08-01

    Breast magnetic resonance imaging (MRI) has become an essential component of breast imaging. Whether it is used as a problem-solving tool or a screening test or for staging patients with breast cancer, it detects many lesions in the breast. The challenge for the radiologist is to distinguish significant from insignificant lesions and to direct their management. A brief summary of the terminology according to the American College of Radiologists lexicon will be provided. This review article will cover the differential diagnosis of enhancing lesions, including masses and nonmass enhancement, from benign and malignant causes. Some of the specific morphologic and kinetic features that help to differentiate benign from malignant lesions will be illustrated, and positive predictive values of these features will be reviewed. The various methods of investigating enhancing lesions of the breast will be discussed, including second-look ultrasound, ultrasound-guided biopsy, stereotactic biopsy, and MRI-guided biopsy. A practical approach to the management of MRI-detected lesions will include timing of follow-up, when to biopsy and when to ignore enhancing lesions in the breast. PMID:21798693

  8. Diseased Region Detection of Longitudinal Knee Magnetic Resonance Imaging Data

    PubMed Central

    Huang, Chao; Shan, Liang; Charles, H. Cecil; Wirth, Wolfgang; Niethammer, Marc; Zhu, Hongtu

    2015-01-01

    Magnetic resonance imaging (MRI) has become an important imaging technique for quantifying the spatial location and magnitude/direction of longitudinal cartilage morphology changes in patients with osteoarthritis (OA). Although several analytical methods, such as subregion-based analysis, have been developed to refine and improve quantitative cartilage analyses, they can be suboptimal due to two major issues: the lack of spatial correspondence across subjects and time and the spatial heterogeneity of cartilage progression across subjects. The aim of this paper is to present a statistical method for longitudinal cartilage quantification in OA patients, while addressing these two issues. The 3D knee image data is preprocessed to establish spatial correspondence across subjects and/or time. Then, a Gaussian hidden Markov model (GHMM) is proposed to deal with the spatial heterogeneity of cartilage progression across both time and OA subjects. To estimate unknown parameters in GHMM, we employ a pseudo-likelihood function and optimize it by using an expectation-maximization (EM) algorithm. The proposed model can effectively detect diseased regions in each OA subject and present a localized analysis of longitudinal cartilage thickness within each latent subpopulation. Our GHMM integrates the strengths of two standard statistical methods including the local subregion-based analysis and the ordered value approach. We use simulation studies and the Pfizer longitudinal knee MRI dataset to evaluate the finite sample performance of GHMM in the quantification of longitudinal cartilage morphology changes. Our results indicate that GHMM significantly outperforms several standard analytical methods. PMID:25823031

  9. Molecular Imaging of Activated Platelets Allows the Detection of Pulmonary Embolism with Magnetic Resonance Imaging

    PubMed Central

    Heidt, Timo; Ehrismann, Simon; Hövener, Jan-Bernd; Neudorfer, Irene; Hilgendorf, Ingo; Reisert, Marco; Hagemeyer, Christoph E.; Zirlik, Andreas; Reinöhl, Jochen; Bode, Christoph; Peter, Karlheinz; von Elverfeldt, Dominik; von zur Muhlen, Constantin

    2016-01-01

    Early and reliable detection of pulmonary embolism (PE) is critical for improving patient morbidity and mortality. The desire for low-threshold screening for pulmonary embolism is contradicted by unfavorable radiation of currently used computed tomography or nuclear techniques, while standard magnetic resonance imaging still struggles to provide sufficient diagnostic sensitivity in the lung. In this study we evaluate a molecular-targeted contrast agent against activated platelets for non-invasive detection of murine pulmonary thromboembolism using magnetic resonance imaging. By intravenous injection of human thrombin, pulmonary thromboembolism were consistently induced as confirmed by immunohistochemistry of the lung. Magnetic resonance imaging after thrombin injection showed local tissue edema in weighted images which co-localized with the histological presence of pulmonary thromboembolism. Furthermore, injection of a functionalized contrast agent targeting activated platelets provided sensitive evidence of focal accumulation of activated platelets within the edematous area, which, ex vivo, correlated well with the size of the pulmonary embolism. In summary, we here show delivery and specific binding of a functionalized molecular contrast agent against activated platelets for targeting pulmonary thromboembolism. Going forward, molecular imaging may provide new opportunities to increase sensitivity of magnetic resonance imaging for detection of pulmonary embolism. PMID:27138487

  10. Molecular Imaging of Activated Platelets Allows the Detection of Pulmonary Embolism with Magnetic Resonance Imaging.

    PubMed

    Heidt, Timo; Ehrismann, Simon; Hövener, Jan-Bernd; Neudorfer, Irene; Hilgendorf, Ingo; Reisert, Marco; Hagemeyer, Christoph E; Zirlik, Andreas; Reinöhl, Jochen; Bode, Christoph; Peter, Karlheinz; von Elverfeldt, Dominik; von Zur Muhlen, Constantin

    2016-01-01

    Early and reliable detection of pulmonary embolism (PE) is critical for improving patient morbidity and mortality. The desire for low-threshold screening for pulmonary embolism is contradicted by unfavorable radiation of currently used computed tomography or nuclear techniques, while standard magnetic resonance imaging still struggles to provide sufficient diagnostic sensitivity in the lung. In this study we evaluate a molecular-targeted contrast agent against activated platelets for non-invasive detection of murine pulmonary thromboembolism using magnetic resonance imaging. By intravenous injection of human thrombin, pulmonary thromboembolism were consistently induced as confirmed by immunohistochemistry of the lung. Magnetic resonance imaging after thrombin injection showed local tissue edema in weighted images which co-localized with the histological presence of pulmonary thromboembolism. Furthermore, injection of a functionalized contrast agent targeting activated platelets provided sensitive evidence of focal accumulation of activated platelets within the edematous area, which, ex vivo, correlated well with the size of the pulmonary embolism. In summary, we here show delivery and specific binding of a functionalized molecular contrast agent against activated platelets for targeting pulmonary thromboembolism. Going forward, molecular imaging may provide new opportunities to increase sensitivity of magnetic resonance imaging for detection of pulmonary embolism. PMID:27138487

  11. 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.

  12. 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

  13. Magnetic resonance imaging in the detection of pancreatic neoplasms.

    PubMed

    Zhong, Liang

    2007-08-01

    Recently, with the rapid scanning time and improved image quality, outstanding advances in magnetic resonance (MR) methods have resulted in an increase in the use of MRI for patients with a variety of pancreatic neoplasms. MR multi-imaging protocol, which includes MR cross-sectional imaging, MR cholangiopancreatography and dynamic contrast-enhanced MR angiography, integrates the advantages of various special imaging techniques. The non-invasive all-in-one MR multi-imaging techniques may provide the comprehensive information needed for the preoperative diagnosis and evaluation of pancreatic neoplasms. Pancreatic neoplasms include primary tumors and pancreatic metastases. Primary tumors of the pancreas may be mainly classified as ductal adenocarcinomas, cystic tumors and islet cell tumors (ICT). Pancreatic adenocarcinomas can be diagnosed in a MRI study depending on direct evidence or both direct and indirect evidence. The combined MRI features of a focal pancreatic mass, pancreatic duct dilatation and parenchymal atrophy are highly suggestive of a ductal adenocarcinoma. Most cystic neoplasms of the pancreas are either microcystic adenomas or mucinous cystic neoplasms. Intraductal papillary mucinous tumors are the uncommon low-grade malignancy of the pancreatic duct. ICT are rare neoplasms arising from neuroendocrine cells in the pancreas or the periampullary region. ICT are classified as functioning and non-functioning. The most frequent tumors to metastasize to the pancreas are cancers of the breast, lung, kidney and melanoma. The majority of metastases present as large solitary masses with well-defined margins. PMID:17650223

  14. Magnetic resonance microwave absorption imaging: Feasibility of signal detection

    PubMed Central

    Xie, Bin; Weaver, John B.; Meaney, Paul M.; Paulsen, Keith D.

    2009-01-01

    Purpose: Magnetic resonance (MR) technique was used to detect small displacements induced by localized absorption of pulsed 434 MHz microwave power as a potential method for tumor detection. Methods: Phase contrast subtraction was used to separate the phase change due to motion from thermoelastic expansion from other contributions to phase variation such as the bulk temperature rise of the medium and phase offsets from the MR scanner itself. A simple set of experiments was performed where the motion was constrained to be one dimensional which provided controls on the data acquisition and motion extraction procedures. Specifically, the MR-detected motion signal was isolated by altering the direction of the microwave-induced motion and sampling the response with motion encoding gradients in all three directions when the microwave power was turned on and turned off. Results: Successful signal detection, as evidenced by the recording of a systematic alternating (zigzag) phase pattern, occurred only when the motion encoding was in parallel with either the vertical or horizontal direction of the microwave-induced motion on both 10 and 4 mm spatial scales. Conclusions: These results demonstrate, for the first time, that motion associated with thermoelastic expansion from the absorption of pulsed microwave power can be detected with MR. PMID:19994529

  15. Detection of single mammalian cells by high-resolution magnetic resonance imaging.

    PubMed Central

    Dodd, S J; Williams, M; Suhan, J P; Williams, D S; Koretsky, A P; Ho, C

    1999-01-01

    This study reports the detection of single mammalian cells, specifically T cells (T lymphocytes) labeled with dextran-coated superparamagnetic iron oxide particles, using magnetic resonance microscopy. Size amplification due to sequestration of the superparamagnetic particles in vacuoles enhances contrast in localized areas in high-resolution magnetic resonance imaging. Magnetic resonance images of samples containing differing concentrations of T cells embedded in 3% gelatin show a number of dark regions due to the superparamagnetic iron oxide particles, consistent with the number predicted by transmission electron microscopy. Colabeling of T cell samples with a fluorescent dye leads to strong correlations between magnetic resonance and fluorescence microscopic images, showing the presence of the superparamagnetic iron oxide particles at the cell site. This result lays the foundation for our approach to tracking the movement of a specific cell type in live animals and humans. PMID:9876127

  16. Time-of-flight detection of ultra-cold atoms using resonant frequency modulation imaging.

    PubMed

    Hardman, K S; Wigley, P B; Everitt, P J; Manju, P; Kuhn, C C N; Robins, N P

    2016-06-01

    Resonant frequency modulation imaging is used to detect free falling ultra-cold atoms. A theoretical comparison of fluorescence imaging (FI) and frequency modulation imaging (FMI) is made, indicating that for low optical depth clouds, FMI accomplished a higher signal-to-noise ratio under conditions necessary for a 200 μm spatially resolved atom interferometer. A 750 ms time-of-flight measurement reveals near atom shot-noise limited number measurements of 2×106 Bose-condensed Rb87 atoms. The detection system is applied to high precision spinor BEC based atom interferometer. PMID:27244400

  17. A Novel Microfluidic Flow Rate Detection Method Based on Surface Plasmon Resonance Temperature Imaging

    PubMed Central

    Deng, Shijie; Wang, Peng; Liu, Shengnan; Zhao, Tianze; Xu, Shanzhi; Guo, Mingjiang; Yu, Xinglong

    2016-01-01

    A novel microfluidic flow rate detection method based on surface plasmon resonance (SPR) temperature imaging is proposed. The measurement is performed by space-resolved SPR imaging of the flow induced temperature variations. Theoretical simulations and analysis were performed to demonstrate a proof of concept using this approach. Experiments were implemented and results showed that water flow rates within a wide range of tens to hundreds of μL/min could be detected. The flow rate sensor is resistant to disturbances and can be easily integrated into microfluidic lab-on-chip systems. PMID:27347960

  18. A Novel Microfluidic Flow Rate Detection Method Based on Surface Plasmon Resonance Temperature Imaging.

    PubMed

    Deng, Shijie; Wang, Peng; Liu, Shengnan; Zhao, Tianze; Xu, Shanzhi; Guo, Mingjiang; Yu, Xinglong

    2016-01-01

    A novel microfluidic flow rate detection method based on surface plasmon resonance (SPR) temperature imaging is proposed. The measurement is performed by space-resolved SPR imaging of the flow induced temperature variations. Theoretical simulations and analysis were performed to demonstrate a proof of concept using this approach. Experiments were implemented and results showed that water flow rates within a wide range of tens to hundreds of μL/min could be detected. The flow rate sensor is resistant to disturbances and can be easily integrated into microfluidic lab-on-chip systems. PMID:27347960

  19. Application of magnetic resonance imaging to non-destructive void detection in watermelon

    NASA Astrophysics Data System (ADS)

    Saito, K.; Miki, T.; Hayashi, S.; Kajikawa, H.; Shimada, M.; Kawate, Y.; Nishizawa, T.; Ikegaya, D.; Kimura, N.; Takabatake, K.; Sugiura, N.; Suzuki, M.

    A novel application of magnetic resonance imaging (MRI) is described. The possibility of utilizing MRI for non-destructive quality evaluation of watermelons was studied. In this study, we applied MRI to the detection of internal voids in watermelons. In order to increase the measurement rate, we employed a one-dimensional projection profile method instead of observing a two-dimensional cross-sectional image. The void detection was carried out with this technique over 30 samples and 28 samples were correctly evaluated. The measurement rate was 900 ms per sample, which is an acceptable speed for a sorting machine in the agricultural field.

  20. Label-free imaging, detection, and mass measurement of single viruses by surface plasmon resonance

    PubMed Central

    Wang, Shaopeng; Shan, Xiaonan; Patel, Urmez; Huang, Xinping; Lu, Jin; Li, Jinghong; Tao, Nongjian

    2010-01-01

    We report on label-free imaging, detection, and mass/size measurement of single viral particles in solution by high-resolution surface plasmon resonance microscopy. Diffraction of propagating plasmon waves along a metal surface by the viral particles creates images of the individual particles, which allow us to detect the binding of the viral particles to surfaces functionalized with and without antibodies. We show that the intensity of the particle image is related to the mass of the particle, from which we determine the mass and mass distribution of influenza viral particles with a mass detection limit of approximately 1 ag (or 0.2 fg/mm2). This work demonstrates a multiplexed method to measure the masses of individual viral particles and to study the binding activity of the viral particles. PMID:20798340

  1. Force-Detected Magnetic Resonance Imaging in Micron-Scale Liquids

    NASA Astrophysics Data System (ADS)

    Sixta, Aimee; Bogat, Sophia; Wright, Diego; Mozaffari, Shirin; Tennant, Daniel; Paster, Jeremy; Markert, John

    We report our efforts in the development of Nuclear Magnetic Resonance Force Microscopy (NMRFM) for the study of biological materials in liquid media at the micron scale. Our probe contains microfluidic samples sealed in thin-walled (few µm) quartz tubes, with a micro-oscillator sensor nearby in vacuum to maintain its high mechanical resonance quality factor. An initial demonstration utilizes a permalloy magnet on the oscillator tip, which provides a resonant slice of thickness 0.5 µm and an area of diameter 10µm these first measurements aim to demonstrate a single-shot measurement of the longitudinal relaxation time T1 in aqueous solutions of Cu2SO4. We also aim to implement a sawtooth 2? cyclic inversion of the nuclear spins, a detection scheme that effectively eliminates common measurement artifacts. At the micron scale, both spin diffusion and physical diffusion in liquids tend to blur images in conventional magnetic resonance imaging (MRI); we aim to exploit the local nature of the NMRFM probe to obtain higher resolution dynamical images, with the ultimate goal of imaging within individual biological cells.

  2. Detection and Imaging of Superoxide in Roots by an Electron Spin Resonance Spin-Probe Method

    PubMed Central

    Warwar, Nasim; Mor, Avishai; Fluhr, Robert; Pandian, Ramasamy P.; Kuppusamy, Periannan; Blank, Aharon

    2011-01-01

    The detection, quantification, and imaging of short-lived reactive oxygen species, such as superoxide, in live biological specimens have always been challenging and controversial. Fluorescence-based methods are nonspecific, and electron spin resonance (ESR) spin-trapping methods require high probe concentrations and lack the capability for sufficient image resolution. In this work, a novel (to our knowledge), sensitive, small ESR imaging resonator was used together with a stable spin probe that specifically reacts with superoxide with a high reaction rate constant. This ESR spin-probe-based methodology was used to examine superoxide generated in a plant root as a result of an apical leaf injury. The results show that the spin probe rapidly permeated the plant's extracellular space. Upon injury of the plant tissue, superoxide was produced and the ESR signal decreased rapidly in the injured parts as well as in the distal part of the root. This is attributed to superoxide production and thus provides a means of quantifying the level of superoxide in the plant. The spin probe's narrow single-line ESR spectrum, together with the sensitive imaging resonator, facilitates the quantitative measurement of superoxide in small biological samples, such as the plant's root, as well as one-dimensional imaging along the length of the root. This type of methodology can be used to resolve many questions involving the production of apoplastic superoxide in plant biology. PMID:21943435

  3. Incidental Bladder Cancer Detected on Multiparametric Magnetic Resonance Imaging of the Prostate Gland

    PubMed Central

    Sardari, Al; Thomas, John V.; Nix, Jeffrey W.; Pietryga, Jason A.; Sanyal, Rupan; Gordetsky, Jennifer B.; Rais-Bahrami, Soroush

    2015-01-01

    The increased use of axial imaging in various fields of medicine has led to an increased frequency of incidental findings, specifically incidental cancer lesions. Hence, as the use of multiparametric magnetic resonance imaging (MP-MRI) for prostate cancer detection, staging, and management becomes more widespread, the potential for additional incidental findings in the pelvis increases. Herein, we report the case of a man on active surveillance for low-grade, early-staged prostate cancer who underwent MP-MRI and was incidentally found to have a high-grade bladder cancer lesion. PMID:26783492

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

    NASA Astrophysics Data System (ADS)

    Kohan, Zohreh; Azmi, Reza

    2016-03-01

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

  5. Resonant Cavity Imaging: A Means Toward High-Throughput Label-Free Protein Detection

    PubMed Central

    Bergstein, David A.; Özkumur, Emre; Wu, Arthur C.; Yalçin, Ayça; Colson, Jeremy R.; Needham, James W.; Irani, Rostem J.; Gershoni, Jonathan M.; Goldberg, Bennett B.; DeLisi, Charles; Ruane, Michael F.; Ünlü, M. Selim

    2009-01-01

    The resonant cavity imaging biosensor (RCIB) is an optical technique for detecting molecular binding interactions label free at many locations in parallel that employs an optical resonant cavity for high sensitivity. Near-infrared light centered at 1512.5 nm couples resonantly through a Fabry–Perot cavity constructed from dielectric reflectors (Si/SiO2), one of which serves as the binding surface. As the wavelength is swept using a tunable laser, a near-infrared digital camera monitors cavity transmittance at each pixel. A wavelength shift in the local resonant response of the optical cavity indicates binding. Positioning the sensing surface with respect to the standing wave pattern of the electric field within the cavity controls the sensitivity with which the presence of bound molecules is detected. Transmitted intensity at thousands of pixel locations is recorded simultaneously in a 10 s, 5 nm scan. An initial proof-of-principle setup has been constructed. A test sample was fabricated with 25, 100-μm wide square features, each with a different density of 1-μm square depressions etched 12 nm into the SiO2 surface. The average depth of each etched region was found with 0.05 nm rms precision. In a second test, avidin, bound selectively to biotin conjugated bovine serum albumin, was detected. PMID:19823593

  6. Ultra-low field magnetic resonance imaging detection with gradient tensor compensation in urban unshielded environment

    NASA Astrophysics Data System (ADS)

    Dong, Hui; Qiu, Longqing; Shi, Wen; Chang, Baolin; Qiu, Yang; Xu, Lu; Liu, Chao; Zhang, Yi; Krause, Hans-Joachim; Offenhäusser, Andreas; Xie, Xiaoming

    2013-03-01

    An ultra-low field (ULF) magnetic resonance imaging (MRI) system was set up in an urban laboratory without magnetic shielding. The measured environmental gradient fields of 1 ˜ 5 μT/m caused image distortion. We designed a gradient detection and compensation system to effectively balance the gradient tensor components. The free induction decay signal duration of tap water was thus extended from 0.3 s to 2.5 s, providing the possibility for high-resolution imaging. Two-dimensional MRI images were then obtained at 130 μT with a helium-cooled second-order superconducting quantum interference device gradiometer. This result allows us to develop an inexpensive ULF MRI system for biological studies.

  7. Automatic detection of larynx cancer from contrast-enhanced magnetic resonance images

    NASA Astrophysics Data System (ADS)

    Doshi, Trushali; Soraghan, John; Grose, Derek; MacKenzie, Kenneth; Petropoulakis, Lykourgos

    2015-03-01

    Detection of larynx cancer from medical imaging is important for the quantification and for the definition of target volumes in radiotherapy treatment planning (RTP). Magnetic resonance imaging (MRI) is being increasingly used in RTP due to its high resolution and excellent soft tissue contrast. Manually detecting larynx cancer from sequential MRI is time consuming and subjective. The large diversity of cancer in terms of geometry, non-distinct boundaries combined with the presence of normal anatomical regions close to the cancer regions necessitates the development of automatic and robust algorithms for this task. A new automatic algorithm for the detection of larynx cancer from 2D gadoliniumenhanced T1-weighted (T1+Gd) MRI to assist clinicians in RTP is presented. The algorithm employs edge detection using spatial neighborhood information of pixels and incorporates this information in a fuzzy c-means clustering process to robustly separate different tissues types. Furthermore, it utilizes the information of the expected cancerous location for cancer regions labeling. Comparison of this automatic detection system with manual clinical detection on real T1+Gd axial MRI slices of 2 patients (24 MRI slices) with visible larynx cancer yields an average dice similarity coefficient of 0.78+/-0.04 and average root mean square error of 1.82+/-0.28 mm. Preliminary results show that this fully automatic system can assist clinicians in RTP by obtaining quantifiable and non-subjective repeatable detection results in a particular time-efficient and unbiased fashion.

  8. Computer aided detection of tumor and edema in brain FLAIR magnetic resonance image using ANN

    NASA Astrophysics Data System (ADS)

    Pradhan, Nandita; Sinha, A. K.

    2008-03-01

    This paper presents an efficient region based segmentation technique for detecting pathological tissues (Tumor & Edema) of brain using fluid attenuated inversion recovery (FLAIR) magnetic resonance (MR) images. This work segments FLAIR brain images for normal and pathological tissues based on statistical features and wavelet transform coefficients using k-means algorithm. The image is divided into small blocks of 4×4 pixels. The k-means algorithm is used to cluster the image based on the feature vectors of blocks forming different classes representing different regions in the whole image. With the knowledge of the feature vectors of different segmented regions, supervised technique is used to train Artificial Neural Network using fuzzy back propagation algorithm (FBPA). Segmentation for detecting healthy tissues and tumors has been reported by several researchers by using conventional MRI sequences like T1, T2 and PD weighted sequences. This work successfully presents segmentation of healthy and pathological tissues (both Tumors and Edema) using FLAIR images. At the end pseudo coloring of segmented and classified regions are done for better human visualization.

  9. Potential Applications of Microtesla Magnetic Resonance ImagingDetected Using a Superconducting Quantum Interference Device

    SciTech Connect

    Myers, Whittier R.

    2006-05-18

    This dissertation describes magnetic resonance imaging (MRI) of protons performed in a precession field of 132 {micro}T. In order to increase the signal-to-noise ratio (SNR), a pulsed 40-300 mT magnetic field prepolarizes the sample spins and an untuned second-order superconducting gradiometer coupled to a low transition temperature superconducting quantum interference device (SQUID) detects the subsequent 5.6-kHz spin precession. Imaging sequences including multiple echoes and partial Fourier reconstruction are developed. Calculating the SNR of prepolarized SQUID-detected MRI shows that three-dimensional Fourier imaging yields higher SNR than slice-selection imaging. An experimentally demonstrated field-cycling pulse sequence and post-processing algorithm mitigate image artifacts caused by concomitant gradients in low-field MRI. The magnetic field noise of SQUID untuned detection is compared to the noise of SQUID tuned detection, conventional Faraday detection, and the Nyquist noise generated by conducting biological samples. A second-generation microtesla MRI system employing a low-noise SQUID is constructed to increase SNR. A 2.4-m cubic, eddy-current shield with 6-mm thick aluminum walls encloses the experiment to attenuate external noise. The measured noise is 0.75 fT Hz{sup -1/2} referred to the bottom gradiometer loop. Solenoids wound from 30-strand braided wire to decrease Nyquist noise and cooled by either liquid nitrogen or water polarize the spins. Copper wire coils wound on wooden supports produce the imaging magnetic fields and field gradients. Water phantom images with 0.8 x 0.8 x 10 mm{sup 3} resolution have a SNR of 6. Three-dimensional 1.6 x 1.9 x 14 mm{sup 3} images of bell peppers and 3 x 3 x 26 mm{sup 3} in vivo images of the human arm are presented. Since contrast based on the transverse spin relaxation rate (T{sub 1}) is enhanced at low magnetic fields, microtesla MRI could potentially be used for tumor imaging. The measured T{sub 1} of ex

  10. Investigation of feline brain anatomy for the detection of cortical spreading depression with magnetic resonance imaging

    PubMed Central

    SMITH, J. M.; JAMES, M. F.; BOCKHORST, K. H. J.; SMITH, M. I.; BRADLEY, D. P.; PAPADAKIS, N. G.; CARPENTER, T. A.; PARSONS, A. A.; LESLIE, R. A.; HALL, L. D.; HUANG, C. L.-H.

    2001-01-01

    Cortical spreading depression (CSD) and peri-infarct depolarisation (PID) are related phenomena that have been associated with the human clinical syndromes of migraine (CSD), head injury and stroke (PID). Nevertheless the existence of CSD in man remains controversial, despite the detection of this phenomenon in the brains of most, if not all, other animal species investigated. This failure to unambiguously detect CSD clinically may be at least partly due to the anatomically complex, gyrencephalic structure of the human brain. This study was designed to establish conditions for the study of CSD in the brain of a gyrencephalic species using the noninvasive technique of magnetic resonance imaging (MRI). The 3-dimensional (3D) gyrencephalic anatomy of the cat brain was examined to determine the imaging conditions necessary to detect CSD events. Orthogonal transverse, sagittal and horizontal T1-weighted image slices showed that the marginal and suprasylvian gyri were the most appropriate cortical structures to study CSD. This was in view of (1) their simple geometry: (2) their lengthy extent of grey matter orientated rostrocaudally in the cortex: (3) their separation by a sulcus across which CSD spread could be studied and (4) the discontinuity in the grey matter in these regions between the right and left hemispheres dorsal to the corpus callosum. The structure suggested by the T1-weighted images was corroborated by systematic diffusion tensor imaging to map the fractional anisotropy and diffusion trace. Thus a single horizontal image plane could visualise the neighbouring suprasylvian and marginal gyri of both cerebral hemispheres, whereas its complex shape and position ruled out the ectosylvian gyrus for CSD studies. With the horizontal imaging plane, CSD events were reproducibly detected by animating successive diffusion-weighted MR images following local KCl stimulation of the cortical surface. In single image frames, CSD detection and characterisation required

  11. Investigation of feline brain anatomy for the detection of cortical spreading depression with magnetic resonance imaging.

    PubMed

    Smith, J M; James, M F; Bockhorst, K H; Smith, M I; Bradley, D P; Papadakis, N G; Carpenter, T A; Parsons, A A; Leslie, R A; Hall, L D; Huang, C L

    2001-05-01

    Cortical spreading depression (CSD) and peri-infarct depolarisation (PID) are related phenomena that have been associated with the human clinical syndromes of migraine (CSD), head injury and stroke (PID). Nevertheless the existence of CSD in man remains controversial, despite the detection of this phenomenon in the brains of most, if not all, other animal species investigated. This failure to unambiguously detect CSD clinically may be at least partly due to the anatomically complex, gyrencephalic structure of the human brain. This study was designed to establish conditions for the study of CSD in the brain of a gyrencephalic species using the noninvasive technique of magnetic resonance imaging (MRI). The 3-dimensional (3D) gyrencephalic anatomy of the cat brain was examined to determine the imaging conditions necessary to detect CSD events. Orthogonal transverse, sagittal and horizontal T1-weighted image slices showed that the marginal and suprasylvian gyri were the most appropriate cortical structures to study CSD. This was in view of (1) their simple geometry: (2) their lengthy extent of grey matter orientated rostrocaudally in the cortex: (3) their separation by a sulcus across which CSD spread could be studied and (4) the discontinuity in the grey matter in these regions between the right and left hemispheres dorsal to the corpus callosum. The structure suggested by the T1-weighted images was corroborated by systematic diffusion tensor imaging to map the fractional anisotropy and diffusion trace. Thus a single horizontal image plane could visualise the neighbouring suprasylvian and marginal gyri of both cerebral hemispheres, whereas its complex shape and position ruled out the ectosylvian gyrus for CSD studies. With the horizontal imaging plane, CSD events were reproducibly detected by animating successive diffusion-weighted MR images following local KCl stimulation of the cortical surface. In single image frames, CSD detection and characterisation required

  12. Polymer Microring Resonators for High-Frequency Ultrasound Detection and Imaging

    PubMed Central

    Maxwell, Adam; Huang, Sheng-Wen; Ling, Tao; Kim, Jin-Sung; Ashkenazi, Shai; Guo, L. Jay

    2009-01-01

    Polymer microring resonators fabricated by nanoimprinting are presented as a means of ultrasound detection. Acoustic waves impinging on a ring-shaped optical resonator cause strain in the ring dimensions, modulating optical output. Basic acoustic and optical characteristics of the microring sensor are presented. Measurements at several frequencies show a high sensitivity and low noise-equivalent pressure. The angular response is determined by sensing the optoacoustic excitation of a 49 μm polyester microsphere and shows wide-angle sensitivity. A 1-D array consisting of 4 microrings is demonstrated using wavelength multiplexing for addressing each element. The high sensitivity, bandwidth, and angular response make it a potentially useful sensor platform for many applications including high-frequency ultrasonic and photoacoustic imaging. PMID:20700482

  13. Semi-automated scar detection in delayed enhanced cardiac magnetic resonance images

    NASA Astrophysics Data System (ADS)

    Morisi, Rita; Donini, Bruno; Lanconelli, Nico; Rosengarden, James; Morgan, John; Harden, Stephen; Curzen, Nick

    2015-06-01

    Late enhancement cardiac magnetic resonance images (MRI) has the ability to precisely delineate myocardial scars. We present a semi-automated method for detecting scars in cardiac MRI. This model has the potential to improve routine clinical practice since quantification is not currently offered due to time constraints. A first segmentation step was developed for extracting the target regions for potential scar and determining pre-candidate objects. Pattern recognition methods are then applied to the segmented images in order to detect the position of the myocardial scar. The database of late gadolinium enhancement (LE) cardiac MR images consists of 111 blocks of images acquired from 63 patients at the University Hospital Southampton NHS Foundation Trust (UK). At least one scar was present for each patient, and all the scars were manually annotated by an expert. A group of images (around one third of the entire set) was used for training the system which was subsequently tested on all the remaining images. Four different classifiers were trained (Support Vector Machine (SVM), k-nearest neighbor (KNN), Bayesian and feed-forward neural network) and their performance was evaluated by using Free response Receiver Operating Characteristic (FROC) analysis. Feature selection was implemented for analyzing the importance of the various features. The segmentation method proposed allowed the region affected by the scar to be extracted correctly in 96% of the blocks of images. The SVM was shown to be the best classifier for our task, and our system reached an overall sensitivity of 80% with less than 7 false positives per patient. The method we present provides an effective tool for detection of scars on cardiac MRI. This may be of value in clinical practice by permitting routine reporting of scar quantification.

  14. Optical immunosensor for endocrine disruptor nanolayer detection by surface plasmon resonance imaging

    NASA Astrophysics Data System (ADS)

    Karabchevsky, Alina; Tsapovsky, Lev; Marks, Robert S.; Abdulhalim, Ibrahim

    2011-10-01

    Endocrine disrupting compounds (EDCs) such as bisphenol A (BPA) and female hormone Estrone are especially prevalent in surface and waste-waters in nano-molar concentrations and therefore, there is a need for sensitive analytical device for their monitoring. We have designed a miniature, low cost and fast surface plasmon resonance (SPR) imaging liquid sensor based on the angular interrogation using Kretschmann configuration with diverged incident monochromatic light. During this paper we present a surface plasmon resonance imaging (SPRI) biosensor to detect EDCs such as BPA and estrone. A pattern of SPR line which is dark intensity line on bright area was reflected at angles range depending on the dielectric constant of the analye: Rabbit Anti-Estrone polyclonal IgG + Estrone 11-MUA attached to the silver or non-specific sensing of BPA in water with nanoprecision. For analyzing the SPR signals we used an efficient detection algorithm based on Radon Transform with less sensitivity to laser speckle noise and nonuniformity of the illumination.

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

    PubMed Central

    Lahmiri, Salim; Boukadoum, Mounir

    2013-01-01

    We present a new automated system for the detection of brain magnetic resonance images (MRI) affected by Alzheimer's disease (AD). The MRI is analyzed by means of multiscale analysis (MSA) to obtain its fractals at six different scales. The extracted fractals are used as features to differentiate healthy brain MRI from those of AD by a support vector machine (SVM) classifier. The result of classifying 93 brain MRIs consisting of 51 images of healthy brains and 42 of brains affected by AD, using leave-one-out cross-validation method, yielded 99.18% ± 0.01 classification accuracy, 100% sensitivity, and 98.20% ± 0.02 specificity. These results and a processing time of 5.64 seconds indicate that the proposed approach may be an efficient diagnostic aid for radiologists in the screening for AD. PMID:24967286

  16. Magnetic Resonance Imaging to Detect Early Molecular and Cellular Changes in Alzheimer's Disease.

    PubMed

    Knight, Michael J; McCann, Bryony; Kauppinen, Risto A; Coulthard, Elizabeth J

    2016-01-01

    Recent pharmaceutical trials have demonstrated that slowing or reversing pathology in Alzheimer's disease is likely to be possible only in the earliest stages of disease, perhaps even before significant symptoms develop. Pathology in Alzheimer's disease accumulates for well over a decade before symptoms are detected giving a large potential window of opportunity for intervention. It is therefore important that imaging techniques detect subtle changes in brain tissue before significant macroscopic brain atrophy. Current diagnostic techniques often do not permit early diagnosis or are too expensive for routine clinical use. Magnetic Resonance Imaging (MRI) is the most versatile, affordable, and powerful imaging modality currently available, being able to deliver detailed analyses of anatomy, tissue volumes, and tissue state. In this mini-review, we consider how MRI might detect patients at risk of future dementia in the early stages of pathological change when symptoms are mild. We consider the contributions made by the various modalities of MRI (structural, diffusion, perfusion, relaxometry) in identifying not just atrophy (a late-stage AD symptom) but more subtle changes reflective of early dementia pathology. The sensitivity of MRI not just to gross anatomy but to the underlying "health" at the cellular (and even molecular) scales, makes it very well suited to this task. PMID:27378911

  17. Magnetic Resonance Imaging to Detect Early Molecular and Cellular Changes in Alzheimer's Disease

    PubMed Central

    Knight, Michael J.; McCann, Bryony; Kauppinen, Risto A.; Coulthard, Elizabeth J.

    2016-01-01

    Recent pharmaceutical trials have demonstrated that slowing or reversing pathology in Alzheimer's disease is likely to be possible only in the earliest stages of disease, perhaps even before significant symptoms develop. Pathology in Alzheimer's disease accumulates for well over a decade before symptoms are detected giving a large potential window of opportunity for intervention. It is therefore important that imaging techniques detect subtle changes in brain tissue before significant macroscopic brain atrophy. Current diagnostic techniques often do not permit early diagnosis or are too expensive for routine clinical use. Magnetic Resonance Imaging (MRI) is the most versatile, affordable, and powerful imaging modality currently available, being able to deliver detailed analyses of anatomy, tissue volumes, and tissue state. In this mini-review, we consider how MRI might detect patients at risk of future dementia in the early stages of pathological change when symptoms are mild. We consider the contributions made by the various modalities of MRI (structural, diffusion, perfusion, relaxometry) in identifying not just atrophy (a late-stage AD symptom) but more subtle changes reflective of early dementia pathology. The sensitivity of MRI not just to gross anatomy but to the underlying “health” at the cellular (and even molecular) scales, makes it very well suited to this task. PMID:27378911

  18. Automated lesion detection in dynamic contrast enhanced magnetic resonance imaging of breast

    NASA Astrophysics Data System (ADS)

    Liang, Xi; Kotagiri, Romamohanarao; Frazer, Helen; Yang, Qing

    2015-03-01

    We propose an automated method in detecting lesions to assist radiologists in interpreting dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) of breast. The aim is to highlight the suspicious regions of interest to reduce the searching time of the lesions and the possibility of radiologists overlooking small regions. In our method, we locate the suspicious regions by applying a threshold on essential features. The features are normalized to reduce the variation between patients. Support vector machine classifier is then applied to exclude normal tissues from these regions, using both kinetic and morphological features extracted in the lesions. In the evaluation of the system on 21 patients with 50 lesions, all lesions were successfully detected with 5.02 false positive regions per breast.

  19. Positive Unanimous Voting Algorithm for Focal Cortical Dysplasia Detection on Magnetic Resonance Image.

    PubMed

    Qu, Xiaoxia; Yang, Jian; Ma, Shaodong; Bai, Tingzhu; Philips, Wilfried

    2016-01-01

    Focal cortical dysplasia (FCD) is the main cause of epilepsy and can be automatically detected via magnetic resonance (MR) images. However, visual detection of lesions is time consuming and highly dependent on the doctor's personal knowledge and experience. In this paper, we propose a new framework for positive unanimous voting (PUV) to detect FCD lesions. Maps of gray matter thickness, gradient, relative intensity, and gray/white matter width are computed in the proposed framework to enhance the differences between lesional and non-lesional regions. Feature maps are further compared with the feature distributions of healthy controls to obtain feature difference maps. PUV driven by feature and feature difference maps is then applied to classify image voxels into lesion and non-lesion. The connected region analysis then refines the classification results by removing the tiny fragment regions consisting of falsely classified positive voxels. The proposed method correctly identified 8/10 patients with FCD lesions and 30/31 healthy people. Experimental results on the small FCD samples demonstrated that the proposed method can effectively reduce the number of false positives and guarantee correct detection of lesion regions compared with four single classifiers and two recent methods. PMID:27092069

  20. Positive Unanimous Voting Algorithm for Focal Cortical Dysplasia Detection on Magnetic Resonance Image

    PubMed Central

    Qu, Xiaoxia; Yang, Jian; Ma, Shaodong; Bai, Tingzhu; Philips, Wilfried

    2016-01-01

    Focal cortical dysplasia (FCD) is the main cause of epilepsy and can be automatically detected via magnetic resonance (MR) images. However, visual detection of lesions is time consuming and highly dependent on the doctor's personal knowledge and experience. In this paper, we propose a new framework for positive unanimous voting (PUV) to detect FCD lesions. Maps of gray matter thickness, gradient, relative intensity, and gray/white matter width are computed in the proposed framework to enhance the differences between lesional and non-lesional regions. Feature maps are further compared with the feature distributions of healthy controls to obtain feature difference maps. PUV driven by feature and feature difference maps is then applied to classify image voxels into lesion and non-lesion. The connected region analysis then refines the classification results by removing the tiny fragment regions consisting of falsely classified positive voxels. The proposed method correctly identified 8/10 patients with FCD lesions and 30/31 healthy people. Experimental results on the small FCD samples demonstrated that the proposed method can effectively reduce the number of false positives and guarantee correct detection of lesion regions compared with four single classifiers and two recent methods. PMID:27092069

  1. Secondary neurolymphomatosis detected by whole-body diffusion-weighted magnetic resonance imaging: a case report.

    PubMed

    Tanaka, Hiroaki; Yoshino, Kazuhiro; Sakaida, Emiko; Hashimoto, Shinichiro; Takeda, Yusuke; Kawajiri, Chika; Takagi, Toshiyuki; Nakaseko, Chiaki

    2013-01-01

    Neurolymphomatosis (NL) is a rare clinical entity defined as peripheral nervous system infiltration by lymphoma. The diagnosis is difficult and often elusive. Whole-body diffusion-weighted magnetic resonance imaging (DW MRI) was developed to enhance the detection of vaguely delineated tumors. Here, we describe the case of a 71-year-old male with secondary NL of diffuse large B-cell lymphoma (DLBCL) that was successfully detected by whole-body DW MRI. The patient was diagnosed with DLBCL extending from the ethmoidal sinus to the nasal cavity, orbital cavity, and anterior cranial fossa. Although he was administered R-THP-COP chemotherapy and the tumor remarkably decreased in size, he developed painful paresthesia and weakness in the left upper and bilateral lower extremities during treatment. Because lymphoma cells were detected in his spinal fluid, high-dose methotrexate (MTX) and weekly intrathecal MTX and cytarabine injections were administered. Test results for lymphoma cells in the spinal fluid became negative ; however, the neurological disorders progressed. Whole-body DW MRI was performed as whole-body screening and could localize NL at the left cervical and bilateral lumbar nerve roots. Both cervical spine plain MRI and enhanced computed tomography performed around the same time could not detect the cervical lesion. Our case report suggests that whole-body DW MRI is a useful diagnostic imaging procedure, especially as whole-body screening in facilities where PET/CT is not available. PMID:24369224

  2. Direct magnetic resonance detection of myelin and prospects for quantitative imaging of myelin density

    PubMed Central

    Wilhelm, Michael J.; Ong, Henry H.; Tsai, Ping-Huei; Hackney, David B.; Wehrli, Felix W.

    2012-01-01

    Magnetic resonance imaging has previously demonstrated its potential for indirectly mapping myelin density, either by relaxometric detection of myelin water or magnetization transfer. Here, we investigated whether myelin can be detected and possibly quantified directly. We identified the spectrum of myelin in the spinal cord in situ as well as in myelin lipids extracted via a sucrose gradient method, and investigated its spectral properties. High-resolution solution NMR spectroscopy showed the extract composition to be in agreement with myelin’s known chemical make-up. The 400-MHz 1H spectrum of the myelin extract, at 20 °C (room temperature) and 37 °C, consists of a narrow water resonance superimposed on a broad envelope shifted ∼3.5 ppm upfield, suggestive of long-chain methylene protons. Superimposed on this signal are narrow components resulting from functional groups matching the chemical shifts of the constituents making up myelin lipids. The spectrum could be modeled as a sum of super-Lorentzians with a T2* distribution covering a wide range of values (0.008–26 ms). Overall, there was a high degree of similarity between the spectral properties of extracted myelin lipids and those found in neural tissue. The normalized difference spectrum had the hallmarks of membrane proteins, not present in the myelin extract. Using 3D radially ramp-sampled proton MRI, with a combination of adiabatic inversion and echo subtraction, the feasibility of direct myelin imaging in situ is demonstrated. Last, the integrated signal from myelin suspensions is shown, both spectroscopically and by imaging, to scale with concentration, suggesting the potential for quantitative determination of myelin density. PMID:22628562

  3. Clinical Outcome of Magnetic Resonance Imaging-Detected Additional Lesions in Breast Cancer Patients

    PubMed Central

    Ha, Gi-Won; Yi, Mi Suk; Lee, Byoung Kil; Jung, Sung Hoo

    2011-01-01

    Purpose The aim of this study was to investigate the clinical outcome of additional breast lesions identified with breast magnetic resonance imaging (MRI) in breast cancer patients. Methods A total of 153 patients who underwent breast MRI between July 2006 and March 2008 were retrospectively reviewed. Thirty-three patients (21.6&) were recommended for second-look ultrasound (US) for further characterization of additional lesions detected on breast MRI and these patients constituted our study population. Results Assessment for lesions detected on breast MRI consisted of the following: 25 benign lesions (73.5&), two indeterminate (5.9%), and seven malignant (20.6%) in 33 patients. Second-look US identified 12 additional lesions in 34 lesions (35.3%) and these lesions were confirmed by histological examination. Of the 12 lesions found in the 11 patients, six (50.0%) including one contralateral breast cancer were malignant. The surgical plan was altered in 18.2% (six of 33) of the patients. The use of breast MRI justified a change in treatment for four patients (66.7%) and caused two patients (33.3&) to undergo unwarranted additional surgical procedures. Conclusion Breast MRI identified additional multifocal or contralateral cancer which was not detected initially on conventional imaging in breast cancer patients. Breast MRI has become an indispensable modality in conjunction with conventional modalities for preoperative evaluation of patients with operable breast cancer. PMID:22031803

  4. Smart nanoprobes for ultrasensitive detection of breast cancer via magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Lee, Jaemin; Yang, Jaemoon; Seo, Sung-Baek; Ko, Hyun-Ju; Suh, Jin-Suck; Huh, Yong-Min; Haam, Seungjoo

    2008-12-01

    Antibody-conjugated hydrophilic magnetic nanocrystals for use as smart nanoprobes were developed for ultrasensitive detection of breast cancer via magnetic resonance (MR) imaging. MnFe2O4 nanocrystals (MNCs) for use as MR imaging contrast agents were synthesized by thermal decomposition to take advantage of their MR signal enhancement effect. The MNC surfaces were then modified with amphiphilic tri-block copolymers (dicarboxy poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol)), not only allowing the MNCs to transfer from the organic to the aqueous phase, but also increasing the colloidal stability of the MNCs by masking poly(ethylene glycol). The physicochemical properties of the synthesized hydrophilic magnetic nanocrystals (HMNCs) were fully investigated. Trastuzumab (TZ), a monoclonal antibody against human epidermal growth factor receptor (HER2/neu), was further conjugated on the surface of HMNCs to specifically target HER2/neu over-expressed breast cancer cells. MR imaging analysis of target cells treated with TZ-conjugated HMNCs (TZ-HMNCs) clearly demonstrated their potential as high-performance nanoprobes for selective imaging.

  5. Detection of Myofascial Herniation on Dynamic Sonography and Magnetic Resonance Imaging

    PubMed Central

    Khaladkar, Sanjay M.; Kondapavuluri, Sushen Kumar; Kamal, Anubhav; Kalra, Raghav; Kamal, Vigyat

    2016-01-01

    Muscle hernia is an uncommon cause of leg swelling. It can be detected in the early stages only if there is a high index of suspicion. It is common in lower extremity compared to the upper extremity. Tibialis anterior muscle in the leg is commonly involved. Dynamic sonography and magnetic resonance imaging (MRI) are the mainstay in their diagnosis, which demonstrate a facial defect with herniation of muscle fibers. We report a case of 23-year-old male patient who presented with a painless swelling in the anterolateral aspect of the left upper leg. Dynamic sonography done with high-resolution probe demonstrated a defect in fascia overlying tibialis anterior with herniation of outer muscle fibers which increased during dorsiflexion and reduced in the supine position at rest. MRI of the left leg confirmed the findings. PMID:26885428

  6. Preoperative prostate biopsy and multiparametric magnetic resonance imaging: reliability in detecting prostate cancer

    PubMed Central

    Porpiglia, Francesco; Russo, Filippo; Manfredi, Matteo; Mele, Fabrizio; Fiori, Cristian; Regge, Daniele

    2015-01-01

    Purpose The aim of the study was to analyse and compare the ability of multiparametric magnetic resonance imaging (mp–MRI) and prostate biopsy (PB) to correctly identify tumor foci in patients undergoing radical prostatectomy (RP) for prostate cancer (PCa). Materials and Methods 157 patients with clinically localised PCa with a PSA <10 ng/mL and a negative DRE diagnosed on the first (12 samples, Group A) or second (18 samples, Group B) PB were enrolled at our institution. All patients underwent mp-MRI with T2-weighted images, diffusion-weighted imaging, dynamic contrast enhanced-MRI prior to RP. A map of comparison describing each positive biopsy sample was created for each patient, with each tumor focus shown on the MRI and each lesion present on the definitive histological examination in order to compare tumor detection and location. The sensitivity of mp-MRI and PB for diagnosis was compared using Student’s t-test. The ability of the two exams to detect the prevalence of Gleason pattern 4 in the identified lesions was compared using a chi-square test. Results Overall sensitivity of PB and mp-MRI to identify tumor lesion was 59.4% and 78.9%, respectively (p<0.0001). PB missed 144/355 lesions, 59 of which (16.6%) were significant. mp-MRI missed 75/355 lesions, 12 of which (3.4%) were significant. No lesions with a GS≥8 were missed. Sensitivity of PB and mp-MRI to detect the prevalence of Gleason pattern 4 was 88.2% and 97.4%, respectively. Conclusions mp-MRI seems to identify more tumor lesions than PB and to provide more information concerning tumor characteristics. PMID:25928518

  7. Magnetic Resonance Imaging (MRI)

    MedlinePlus

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

  8. Towards MIB-1 and p53 detection in glioma magnetic resonance image: a novel computational image analysis method

    NASA Astrophysics Data System (ADS)

    Liu, Chenbin; Zhang, Haishi; Pan, Ying; Huang, Fengping; Xia, Shunren

    2012-12-01

    Glioma is the primary tumor in the central nervous system, and poses one of the greatest challenges in clinical treatment. MIB-1 and p53 are the most useful biomarkers for gliomas and could help neurosurgeons establish a therapeutic schedule. However, these biomarkers are commonly detected with the help of immunohistochemistry (IHC), which wastes time and energy and is often influenced by subjective factors. To reduce the subjective factors and improve the efficiency in the judgment of IHC, a novel magnetic resonance image (MRI) analysis method is proposed in the present study to detect the expression status of MIB-1 and p53 in IHC. The proposed method includes two kinds of MRI acquisition (FLAIR and T1 FLAIR images), regions of interest (ROIs) selection, texture features (i.e. the gray level gradient co-occurrence matrix (GLGCM), Minkowski functions (MFs), etc) extraction in ROIs, and classification with a support vector machine in a leave-one-out cross validation strategy. By classifying the ROIs, the performance of the method was evaluated by accuracy, area under ROC curve (AUC), etc. A high accuracy (0.7640 ± 0.0225) and AUC (0.7873 ± 0.0377) for MIB-I detection were achieved. In terms of the texture features, 0.7621 ± 0.0199, 0.7666 ± 0.0365 and 0.7426 ± 0.0451 AUC can be obtained using only GLCM, RLM or GLGCM for MIB-1 detection, respectively. In all, the experimental results demonstrated that MR image texture features are associated with the expression status of MIB-1 and p53. The proposed method has the potential to realize high accuracy and robust detection for MIB-I expression status, which makes it promising for clinical glioma diagnosis and prognosis.

  9. Numerical study of remote detection outside the magnet with travelling wave Magnetic Resonance Imaging at 3T

    NASA Astrophysics Data System (ADS)

    López, M.; Vázquez, F.; Solís-Nájera, S.; Rodriguez, A. O.

    2015-01-01

    The use of the travelling wave approach for high magnetic field magnetic resonance imaging has been used recently with very promising results. This approach offer images one with greater field-of-view and a reasonable signal-to-noise ratio using a circular waveguide. This scheme has been proved to be successful at 7 T and 9.4 T with whole-body imager. Images have also been acquired with clinical magnetic resonance imaging systems whose resonant frequencies were 64 MHz and 128 MHz. These results motivated the use of remote detection of the magnetic resonance signal using a parallel-plate waveguide together with 3 T clinical scanners, to acquired human leg images. The cut-off frequency of this waveguide is zero for the principal mode, allowing us to overcome the barrier of transmitting waves at lower frequency than 300 MHz or 7 T for protons. These motivated the study of remote detection outside the actual magnet. We performed electromagnetic field simulations of a parallel-plate waveguide and a phantom. The signal transmission was done at 128 MHz and using a circular surface coil located almost 200 cm away for the magnet isocentre. Numerical simulations demonstrated that the magnetic field of the principal mode propagate inside a waveguide outside the magnet. Numerical results were compared with previous experimental-acquired image data under similar conditions.

  10. In vivo detection of magnetic labeled oxidized multi-walled carbon nanotubes by magnetic resonance imaging.

    PubMed

    Li, Ruibin; Wu, Ren'an; Zhao, Liang; Qin, Hongqiang; Wu, Jianlin; Zhang, Jingwen; Bao, Ruyi; Zou, Hanfa

    2014-12-12

    Functionalized carbon nanotubes (f-CNTs) have been widely used in bio-medicine as drug carriers, bio-sensors, imaging agents and tissue engineering additives, which demands better understanding of their in vivo behavior because of the increasing exposure potential to humans. However, there are limited studies to investigate the in vivo biodistribution and elimination of f-CNTs. In this study, superparamagnetic iron oxides (SPIOs) were used to label oxidized multiwalled carbon nanotubes (o-MWCNTs) for in vivo distribution study of o-MWCNTs by magnetic resonance imaging (MRI). SPIO labeled o-MWCNTs (((SPIO))o-MWCNTs) were prepared by a hydrothermal reaction process, and characterized by TEM, XRD and magnetometer. ((SPIO))o-MWCNTs exhibited superparamagnetic property, excellent biocompatibility and stability. The intravenously injected ((SPIO))o-MWCNTs were observed in liver, kidney and spleen, while the subcutaneously injected ((SPIO))o-MWCNTs could be only detected in sub mucosa. Most of the intravenously injected ((SPIO))o-MWCNTs could be eliminated from liver, spleen, kidney and sub mucosa on 4 d post injection (P.I.). However, the residual o-MWCNTs could induce 30-40% MRI signal-to-noise ratio changes in these tissues even on 30 d P.I. This in vivo biodistribution and elimination information of o-MWCNTs will greatly facilitate the application of f-CNT based nanoproducts in biomedicine. In addition, the magnetic labeling method provides an approach to investigate the in vivo biodistribution and clearance of other nanomaterials. PMID:25409786

  11. Molecular imaging of mesothelioma by detection of manganese-superoxide dismutase activity using manganese-enhanced magnetic resonance imaging.

    PubMed

    Hasegawa, Sumitaka; Koshikawa-Yano, Michiko; Saito, Shigeyoshi; Morokoshi, Yukie; Furukawa, Takako; Aoki, Ichio; Saga, Tsuneo

    2011-05-01

    Malignant mesothelioma (MM) is a fatal malignancy with a rapidly increasing incidence in industrialized countries because of the widespread use of asbestos in the past centuries. Early diagnosis of MM is critical for a better prognosis, but this is often difficult because of the lack of disease-specific diagnostic imaging. Here, we report that manganese-enhanced magnetic resonance imaging (MEMRI) represents a promising approach for a more selective mesothelioma imaging by monitoring a high-level expression of manganese-superoxide dismutase (Mn-SOD), which is observed in many MM. We found that most human MM cells overexpressed Mn-SOD protein compared with human mesothelial cells and that NCI-H226 human MM cells highly expressed Mn-SOD and augmented Mn accumulation when loaded with manganese chloride (MnCl(2)). The cells showed marked T(1)-signal enhancement on in vitro MRI after incubation with MnCl(2) because of the T(1) shortening effect of Mn(2+). H226 subcutaneous tumor was preferentially enhanced compared with a lung adenocarcinoma cell tumor and another human MM cell tumor in MnCl(2)-enhanced T(1)-weighted MR image (T(1)WI), correlating with their respective Mn-SOD expression levels. Moreover, in a more clinically relevant setting, H226 xenografted pleural tumor was markedly enhanced and readily detected by MEMRI using manganese dipyridoxyl diphosphate (MnDPDP), a clinically used contrast agent, as well as MnCl(2). Therefore, we propose that MEMRI can be a potentially powerful method for noninvasive detection of MM, with high spatial resolution and marked signal enhancement, by targeting Mn-SOD. PMID:20617513

  12. Incidental Memory Encoding Assessed with Signal Detection Theory and Functional Magnetic Resonance Imaging (fMRI)

    PubMed Central

    Clemens, Benjamin; Regenbogen, Christina; Koch, Kathrin; Backes, Volker; Romanczuk-Seiferth, Nina; Pauly, Katharina; Shah, N. Jon; Schneider, Frank; Habel, Ute; Kellermann, Thilo

    2015-01-01

    In functional magnetic resonance imaging (fMRI) studies that apply a “subsequent memory” approach, successful encoding is indicated by increased fMRI activity during the encoding phase for hits vs. misses, in areas underlying memory encoding such as the hippocampal formation. Signal-detection theory (SDT) can be used to analyze memory-related fMRI activity as a function of the participant’s memory trace strength (d′). The goal of the present study was to use SDT to examine the relationship between fMRI activity during incidental encoding and participants’ recognition performance. To implement a new approach, post-experimental group assignment into High- or Low Performers (HP or LP) was based on 29 healthy participants’ recognition performance, assessed with SDT. The analyses focused on the interaction between the factors group (HP vs. LP) and recognition performance (hits vs. misses). A whole-brain analysis revealed increased activation for HP vs. LP during incidental encoding for remembered vs. forgotten items (hits > misses) in the insula/temporo-parietal junction (TPJ) and the fusiform gyrus (FFG). Parameter estimates in these regions exhibited a significant positive correlation with d′. As these brain regions are highly relevant for salience detection (insula), stimulus-driven attention (TPJ), and content-specific processing of mnemonic stimuli (FFG), we suggest that HPs’ elevated memory performance was associated with enhanced attentional and content-specific sensory processing during the encoding phase. We provide first correlative evidence that encoding-related activity in content-specific sensory areas and content-independent attention and salience detection areas influences memory performance in a task with incidental encoding of facial stimuli. Based on our findings, we discuss whether the aforementioned group differences in brain activity during incidental encoding might constitute the basis of general differences in memory performance

  13. Vertebral artery hypoplasia, posterior circulation infarction and relative hypoperfusion detected by perfusion magnetic resonance imaging semiquantitatively.

    PubMed

    Zhang, Dao Pei; Ma, Qian Kun; Zhang, Jie Wen; Zhang, Shu Ling; Lu, Gui Feng; Yin, Suo

    2016-09-15

    Vertebral artery hypoplasia (VAH) has been considered a risk factor of posterior circulation infarction (PCI), especially in the territory of the posterior inferior cerebellar artery (PICA). But whether VAH is an independent risk factor for PCI remains uncertain and how VAH participates in the evolvement of PCI is still not clear either. Therefore, this study aims to examine whether VAH is an independent risk factor for PCI and evaluate the effect of VAH on the cerebral perfusion in the territory of the PICA detected by perfusion magnetic resonance imaging (MRI) semiquantitatively. Both univariate and multivariate analyses showed that VAH, hypertension and smoking were more frequent in patients with PCI than in patients without PCI. Perfusion MRI analysis found that there were remarkable differences in the frequency of the relative cerebral blood flow (rCBF) value ≤0.85 and the relative time to peak (rTTP) values between VAH patients without PCI and non-VAH patients without PCI. Our results indicated that VAH may be an independent risk factor for PCI, especially in the presence of hypertension and smoking and that a relative hypoperfusion associates with VAH that may contribute to the evolvement of the infarction in the PICA territory. PMID:27538599

  14. Early detection of cervical spondylotic myelopathy using diffusion tensor imaging: Experiences in 1.5-tesla magnetic resonance imaging.

    PubMed

    Ahmadli, Uzeyir; Ulrich, Nils H; Yuqiang, Yao; Nanz, Daniel; Sarnthein, Johannes; Kollias, Spyros S

    2015-10-01

    The purpose of this study was to investigate the usefulness of diffusion tensor imaging (DTI) for early detection of pathological alterations in the myelon in patients with cervical spondylotic myelopathy (CSM) without T2-weighted imaging (T2W) signal abnormalities but with a narrowed spinal canal with corresponding clinical correlation. Axial DTI at 1.5T together with routine magnetic resonance imaging was performed on 18 patients fulfilling above mentioned criteria. Quantitative fractional anisotropy (FA) and apparent diffusion coefficient (ADC) maps were generated. Values at the narrowest cervical levels were compared to pre- and poststenotic levels and the interindividual means were tested for statistically significant differences by means of paired t-tests. The correlation between the grade and width of canal stenosis in the axial plane was measured. FA was significantly reduced at the stenotic level, compared to prestenotic level, whereas no significant differences were found when compared to poststenotic level. No significant differences between ADC values at stenotic level versus both adjacent non-stenotic levels were found, suggesting very early stage of degeneration. ADC values correlated significantly with the width of the spinal canal at the prestenotic level, but not at the poststenotic level. Findings indicate sufficient robustness of routine implementation of DTI at 1.5T to detect abnormalities in the spinal cord of CSM patients, before apparent T2W signal abnormalities and marked clinical deterioration. Therefore, larger and long-term studies should be conducted to establish the DTI scalar metrics that would indicate early intervention for a better clinical outcome in patients with clinical signs of CSM. PMID:26452521

  15. Spectral surface plasmon resonance imaging for the detection of clenbuterol via three-dimensional immobilization of bioprobes.

    PubMed

    Yao, Manwen; Wu, Yichuan; Fang, Xiangyi; Yang, Yucong; Liu, Hongjun

    2015-04-15

    A method of immobilizing clenbuterol (CLEN) on the sensor chip for spectral surface plasmon resonance imaging (SPRi) was experimentally investigated. The bioprobes on the sensor chip were prepared by immobilizing bovine serum albumin (BSA) protein and conjugating CLEN molecules to BSA, which provides more active points and free orientations for specific binding. The calibration curve showed that the wavelength resonance shift decreased as the concentration of CLEN analyte increased, consistent with the inhibition principle. The limit of detection (LOD) was estimated to be 6.32 μg/ml. This method proved to be highly specific, high throughput, label free, and operationally convenient. PMID:25637304

  16. Wavelet-based enhancement for detection of left ventricular myocardial boundaries in magnetic resonance images.

    PubMed

    Fu, J C; Chai, J W; Wong, S T

    2000-11-01

    MRI is noninvasive and generates clear images, giving it great potential as a diagnostic instrument. However, current methods of image analysis are too time-consuming for dynamic systems such as the cardiovascular system. Since dynamic imagery generate a huge number of images, a computer aided machine vision diagnostic tool is essential for implementing MRI-based measurement. In this paper, a wavelet-based image technique is applied to enhance left ventricular endocardial and epicardial profiles as the preprocessor for a dynamic programming-based automatic border detection algorithm. Statistical tests are conducted to verify the performance of the enhancement technique by comparing borders manually drawn with 1. borders generated from the enhanced images, and 2. borders generated for the original images. PMID:11118768

  17. A poly(dimethylsiloxane) based prism for surface plasmon resonance imaging system and its application for gas detection

    NASA Astrophysics Data System (ADS)

    Zhang, L. L.; Chen, X.; Sun, J. H.; Cai, H. Y.; Li, H.; Chao, Y. P.; Cui, D. F.

    2013-03-01

    This paper presents a surface plasmon resonance (SPR) imaging system based on a low-cost, convenient poly(dimethylsiloxane) (PDMS) prism featured with a close contact with the gold film. Compared to conventional glass prism, both numerical simulations and experimental studies indicated a deeper but wider absorption peak with a higher coupling angle for the PDMS based prism. System repeatability was quantified by the cycled detection of helium and air, with the effect of the flow rate investigated. Furthermore, five types of gases (nitrogen, air, oxygen, hydrogen, and helium) were detected and differentiated by the SPR system, with a calculated sensitivity of 5 × 10-6 RIU.

  18. Detection of brain pathology by magnetic resonance imaging of iron oxide micro-particles.

    PubMed

    Anthony, Daniel C; Sibson, Nicola R; McAteer, Martina A; Davis, Ben; Choudhury, Robin P

    2011-01-01

    Contrast agents are widely used with magnetic resonance imaging (MRI) to increase the contrast between regions of interest and the background signal, thus providing better quality information. Such agents can work in one of two ways, either to specifically enhance the signal that is produced or to localize in a specific cell type of tissue. Commonly used image contrast agents are typically based on gadolinium complexes or super-paramagnetic iron oxide, the latter of which is used for imaging lymph nodes. When blood-brain barrier (BBB) breakdown is a feature of central nervous system (CNS) pathology, intravenously administered contrast agent enters into the CNS and alters contrast on MR scans. However, BBB breakdown reflects downstream or end-stage pathology. The initial recruitment of leukocytes to sites of disease such as multiple sclerosis (MS), ischemic lesions, or tumours takes place across an intact, but activated, brain endothelium. Molecular imaging affords the ability to obtain a "non-invasive biopsy" to reveal the presence of brain pathology in the absence of significant structural changes. We have developed smart contrast agents that target and reversibly adhere to sites of disease and have been used to reveal activated brain endothelium when images obtained by conventional MRI look normal. Indeed, our selectively targeted micro-particles of iron oxide have revealed the early presence of cerebral malaria pathology and ongoing MS-like plaques in clinically relevant models of disease. PMID:21082373

  19. Usefulness of magnetic resonance imaging for detecting intrasubstance tear and/or degeneration of lateral discoid meniscus.

    PubMed

    Hamada, M; Shino, K; Kawano, K; Araki, Y; Matsui, Y; Doi, T

    1994-12-01

    In order to determine the usefulness of magnetic resonance imaging (MRI) for detection of intrasubstance tears or degeneration of the lateral discoid meniscus, we compared findings obtained with MRI with those of histological examination. Sixty-four symptomatic lateral discoid menisci were studied using MRI before surgical treatment. Of these, 18 (28%) met the criteria that MRI signals did not extend to the surface and that no visible tears were observable at arthroscopy. Findings of intrameniscal regions of high signal intensity and flattening in shape on MR images were found to represent intrasubstance tears or degeneration not detected at arthroscopy. Our findings thus demonstrate that MRI is more sensitive than arthroscopy in the detection of intrasubstance pathologies of the lateral discoid menisci. PMID:7880357

  20. Automatic detection of ionospheric Alfvén resonances using signal and image processing techniques

    NASA Astrophysics Data System (ADS)

    Beggan, C. D.

    2014-08-01

    Induction coils permit the measurement of small and very rapid changes of the magnetic field. A new set of induction coils in the UK (at L = 3.2) record magnetic field changes over an effective frequency range of 0.1-40 Hz, encompassing phenomena such as the Schumann resonances, magnetospheric pulsations and ionospheric Alfvén resonances (IARs). The IARs typically manifest themselves as a series of spectral resonance structures (SRSs) within the 1-10 Hz frequency range, usually appearing as fine bands or fringes in spectrogram plots and occurring almost daily during local night-time, disappearing during the daylight hours. The behaviour of the occurrence in frequency (f) and the difference in frequency between fringes (Δf) varies throughout the year. In order to quantify the daily, seasonal and annual changes of the SRSs, we developed a new method based on signal and image processing techniques to identify the fringes and to quantify the values of f, Δf and other relevant parameters in the data set. The technique is relatively robust to noise though requires tuning of threshold parameters. We analyse 18 months of induction coil data to demonstrate the utility of the method.

  1. Automatic computer-aided detection of prostate cancer based on multiparametric magnetic resonance image analysis

    NASA Astrophysics Data System (ADS)

    Vos, P. C.; Barentsz, J. O.; Karssemeijer, N.; Huisman, H. J.

    2012-03-01

    In this paper, a fully automatic computer-aided detection (CAD) method is proposed for the detection of prostate cancer. The CAD method consists of multiple sequential steps in order to detect locations that are suspicious for prostate cancer. In the initial stage, a voxel classification is performed using a Hessian-based blob detection algorithm at multiple scales on an apparent diffusion coefficient map. Next, a parametric multi-object segmentation method is applied and the resulting segmentation is used as a mask to restrict the candidate detection to the prostate. The remaining candidates are characterized by performing histogram analysis on multiparametric MR images. The resulting feature set is summarized into a malignancy likelihood by a supervised classifier in a two-stage classification approach. The detection performance for prostate cancer was tested on a screening population of 200 consecutive patients and evaluated using the free response operating characteristic methodology. The results show that the CAD method obtained sensitivities of 0.41, 0.65 and 0.74 at false positive (FP) levels of 1, 3 and 5 per patient, respectively. In conclusion, this study showed that it is feasible to automatically detect prostate cancer at a FP rate lower than systematic biopsy. The CAD method may assist the radiologist to detect prostate cancer locations and could potentially guide biopsy towards the most aggressive part of the tumour.

  2. Normalized gradient fields cross-correlation for automated detection of prostate in magnetic resonance images

    NASA Astrophysics Data System (ADS)

    Fotin, Sergei V.; Yin, Yin; Periaswamy, Senthil; Kunz, Justin; Haldankar, Hrishikesh; Muradyan, Naira; Cornud, François; Turkbey, Baris; Choyke, Peter L.

    2012-02-01

    Fully automated prostate segmentation helps to address several problems in prostate cancer diagnosis and treatment: it can assist in objective evaluation of multiparametric MR imagery, provides a prostate contour for MR-ultrasound (or CT) image fusion for computer-assisted image-guided biopsy or therapy planning, may facilitate reporting and enables direct prostate volume calculation. Among the challenges in automated analysis of MR images of the prostate are the variations of overall image intensities across scanners, the presence of nonuniform multiplicative bias field within scans and differences in acquisition setup. Furthermore, images acquired with the presence of an endorectal coil suffer from localized high-intensity artifacts at the posterior part of the prostate. In this work, a three-dimensional method for fast automated prostate detection based on normalized gradient fields cross-correlation, insensitive to intensity variations and coil-induced artifacts, is presented and evaluated. The components of the method, offline template learning and the localization algorithm, are described in detail. The method was validated on a dataset of 522 T2-weighted MR images acquired at the National Cancer Institute, USA that was split in two halves for development and testing. In addition, second dataset of 29 MR exams from Centre d'Imagerie Médicale Tourville, France were used to test the algorithm. The 95% confidence intervals for the mean Euclidean distance between automatically and manually identified prostate centroids were 4.06 +/- 0.33 mm and 3.10 +/- 0.43 mm for the first and second test datasets respectively. Moreover, the algorithm provided the centroid within the true prostate volume in 100% of images from both datasets. Obtained results demonstrate high utility of the detection method for a fully automated prostate segmentation.

  3. 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.

  4. 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…

  5. Cardiac Magnetic Resonance Imaging Might Complement Two-Dimensional Echocardiography in the Detection of a Reversible Nonischemic Cardiomyopathy

    PubMed Central

    Madanieh, Raef; Mathew, Shawn; Shah, Pratik; Vatti, Satya K.; Madanieh, Abed; Kosmas, Constantine E.; Vittorio, Timothy J.

    2015-01-01

    We report a case of reversible nonischemic dilated cardiomyopathy in a male in his 60s who presented with an acute heart failure syndrome. Both conventional two-dimensional echocardiography and cardiac magnetic resonance imaging (cMRI) demonstrated severe left ventricular systolic dysfunction; however, both modalities were devoid of significant valvular heart disease as well as the presence of fibrosis, infiltration, inflammation, and scar. After six months of aggressive neurohumoral modulation, there was complete reverse remodeling and normalization of left ventricular function, which highlights the role of cMRI as an adjunct to two-dimensional echocardiography in the detection of a potentially reversible nonischemic cardiomyopathy. PMID:26740746

  6. Role of magnetic resonance imaging in the detection and characterization of solid pancreatic nodules: An update

    PubMed Central

    Ansari, Najwa Al; Ramalho, Miguel; Semelka, Richard C; Buonocore, Valeria; Gigli, Silvia; Maccioni, Francesca

    2015-01-01

    Pancreatic ductal adenocarcinoma is the most common malignant tumor of the pancreas. The remaining pancreatic tumors are a diverse group of pancreatic neoplasms that comprises cystic pancreatic neoplasms, endocrine tumors and other uncommon pancreatic tumors. Due to the excellent soft tissue contrast resolution, magnetic resonance imaging (MRI) is frequently able to readily separate cystic from noncystic tumors. Cystic tumors are often easy to diagnose with MRI; however, noncystic non-adenocarcinoma tumors may show a wide spectrum of imaging features, which can potentially mimic ductal adenocarcinoma. MRI is a reliable technique for the characterization of pancreatic lesions. The implementation of novel motion-resistant pulse sequences and respiratory gating techniques, as well as the recognized benefits of MR cholangiopancreatography, make MRI a very accurate examination for the evaluation of pancreatic masses. MRI has the distinctive ability of non-invasive assessment of the pancreatic ducts, pancreatic parenchyma, neighbouring soft tissues, and vascular network in one examination. MRI can identify different characteristics of various solid pancreatic lesions, potentially allowing the differentiation of adenocarcinoma from other benign and malignant entities. In this review we describe the MRI protocols and MRI characteristics of various solid pancreatic lesions. Recognition of these characteristics may establish the right diagnosis or at least narrow the differential diagnosis, thus avoiding unnecessary tests or procedures and permitting better management. PMID:26644822

  7. A meta-classifier for detecting prostate cancer by quantitative integration of in vivo magnetic resonance spectroscopy and magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Viswanath, Satish; Tiwari, Pallavi; Rosen, Mark; Madabhushi, Anant

    2008-03-01

    Recently, in vivo Magnetic Resonance Imaging (MRI) and Magnetic Resonance Spectroscopy (MRS) have emerged as promising new modalities to aid in prostate cancer (CaP) detection. MRI provides anatomic and structural information of the prostate while MRS provides functional data pertaining to biochemical concentrations of metabolites such as creatine, choline and citrate. We have previously presented a hierarchical clustering scheme for CaP detection on in vivo prostate MRS and have recently developed a computer-aided method for CaP detection on in vivo prostate MRI. In this paper we present a novel scheme to develop a meta-classifier to detect CaP in vivo via quantitative integration of multimodal prostate MRS and MRI by use of non-linear dimensionality reduction (NLDR) methods including spectral clustering and locally linear embedding (LLE). Quantitative integration of multimodal image data (MRI and PET) involves the concatenation of image intensities following image registration. However multimodal data integration is non-trivial when the individual modalities include spectral and image intensity data. We propose a data combination solution wherein we project the feature spaces (image intensities and spectral data) associated with each of the modalities into a lower dimensional embedding space via NLDR. NLDR methods preserve the relationships between the objects in the original high dimensional space when projecting them into the reduced low dimensional space. Since the original spectral and image intensity data are divorced from their original physical meaning in the reduced dimensional space, data at the same spatial location can be integrated by concatenating the respective embedding vectors. Unsupervised consensus clustering is then used to partition objects into different classes in the combined MRS and MRI embedding space. Quantitative results of our multimodal computer-aided diagnosis scheme on 16 sets of patient data obtained from the ACRIN trial, for which

  8. Development of magnetic resonance imaging based detection methods for beta amyloids via sialic acid-functionalized magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Kouyoumdjian, Hovig

    The development of a non-invasive method for the detection of Alzheimer's disease is of high current interest, which can be critical in early diagnosis and in guiding preventive treatment of the disease. The aggregates of beta amyloids are a pathological hallmark of Alzheimer's disease. Carbohydrates such as sialic acid terminated gangliosides have been shown to play significant roles in initiation of amyloid aggregation. Herein, we report a biomimetic approach using sialic acid coated iron oxide superparamagnetic nanoparticles for in vitro detection in addition to the assessment of the in vivo mouse-BBB (Blood brain barrier) crossing of the BSA (bovine serum albumin)-modified ones. The sialic acid functionalized dextran nanoparticles were shown to bind with beta amyloids through several techniques including ELISA (enzyme linked immunosorbent assay), MRI (magnetic resonance imaging), TEM (transmission electron microscopy), gel electrophoresis and tyrosine fluorescence assay. The superparamagnetic nature of the nanoparticles allowed easy detection of the beta amyloids in mouse brains in both in vitro and ex vivo model by magnetic resonance imaging. Furthermore, the sialic acid nanoparticles greatly reduced beta amyloid induced cytotoxicity to SH-SY5Y neuroblastoma cells, highlighting the potential of the glyconanoparticles for detection and imaging of beta amyloids. Sialic acid functionalized BSA (bovine serum albumin) nanoparticles also showed significant binding to beta amyloids, through ELISA and ex vivo mouse brain MRI experiments. Alternatively, the BBB crossing was demonstrated by several techniques such as confocal microscopy, endocytosis, exocytosis assays and were affirmed by nanoparticles transcytosis assays through bEnd.3 endothelial cells. Finally, the BBB crossing was confirmed by analyzing the MRI signal of nanoparticle-injected CD-1 mice.

  9. Hemorrhage detection during focused-ultrasound induced blood-brain-barrier opening by using susceptibility-weighted magnetic resonance imaging.

    PubMed

    Liu, Hao-Li; Wai, Yau-Yau; Chen, Wen-Shiang; Chen, Jin-Chung; Hsu, Po-Hong; Wu, Xin-Yu; Huang, Wen-Cheng; Yen, Tzu-Chen; Wang, Jiun-Jie

    2008-04-01

    High-intensity focused ultrasound has been discovered to be able to locally and reversibly increase the permeability of the blood-brain barrier (BBB), which can be detected using magnetic resonance imaging (MRI). However, side effects such as microhemorrhage, erythrocyte extravasations or even extensive hemorrhage may also occur. Although current contrast-enhanced T1-weighted MRI can be used to detect the changes in BBB permeability, its efficacy in detecting tissue hemorrhage after focused-ultrasound sonication remains limited. The purpose of this study is to investigate the feasibility of magnetic resonance susceptibility-weighted imaging (MR-SWI) for identifying possible tissue hemorrhage associated with disruption of the BBB induced by focused ultrasound in a rat model. The brains of 42 Sprague-Dawley rats were subjected to 107 sonications, either unilaterally or bilaterally. Localized BBB opening was achieved by delivering burst-mode focused ultrasound energy into brain tissue in the presence of microbubbles. Rats were studied by T2-weighted and contrast-enhanced T1-weighted MRI techniques, as well as by SWI. Tissue changes were analyzed histologically and the extent of apoptosis was investigated with the terminal deoxynucleotidyl transferase biotin-dUTP nick-end labeling method. The results demonstrated that SWI is more sensitive than standard T2-weighted and contrast-enhanced T1-weighted MRI techniques in detecting hemorrhages after brain sonication. Longitudinal study showed that SWI is sensitive to the recovery process of the damage and, therefore, could provide important and complementary information to the conventional MR images. Potential applications such as drug delivery in the brain might be benefited. PMID:18313204

  10. Hybrid photomultiplier tube and photodiode parallel detection array for wideband optical spectroscopy of the breast guided by magnetic resonance imaging

    PubMed Central

    Mastanduno, Michael A.; Jiang, Shudong; Pogue, Brian W.; Paulsen, Keith D.

    2013-01-01

    Abstract. A new optical parallel detection system of hybrid frequency and continuous-wave domains was developed to improve the data quality and accuracy in recovery of all breast optical properties. This new system was deployed in a previously existing system for magnetic resonance imaging (MRI)-guided spectroscopy, and allows incorporation of additional near-infrared wavelengths beyond 850 nm, with interlaced channels of photomultiplier tubes (PMTs) and silicon photodiodes (PDs). The acquisition time for obtaining frequency-domain data at six wavelengths (660, 735, 785, 808, 826, and 849 nm) and continuous-wave data at three wavelengths (903, 912, and 948 nm) is 12 min. The dynamic ranges of the detected signal are 105 and 106 for PMT and PD detectors, respectively. Compared to the previous detection system, the SNR ratio of frequency-domain detection was improved by nearly 103 through the addition of an RF amplifier and the utilization of programmable gain. The current system is being utilized in a clinical trial imaging suspected breast cancer tumors as detected by contrast MRI scans. PMID:23979460

  11. Hybrid photomultiplier tube and photodiode parallel detection array for wideband optical spectroscopy of the breast guided by magnetic resonance imaging.

    PubMed

    El-Ghussein, Fadi; Mastanduno, Michael A; Jiang, Shudong; Pogue, Brian W; Paulsen, Keith D

    2014-01-01

    A new optical parallel detection system of hybrid frequency and continuous-wave domains was developed to improve the data quality and accuracy in recovery of all breast optical properties. This new system was deployed in a previously existing system for magnetic resonance imaging (MRI)-guided spectroscopy, and allows incorporation of additional near-infrared wavelengths beyond 850 nm, with interlaced channels of photomultiplier tubes (PMTs) and silicon photodiodes (PDs). The acquisition time for obtaining frequency-domain data at six wavelengths (660, 735, 785, 808, 826, and 849 nm) and continuous-wave data at three wavelengths (903, 912, and 948 nm) is 12 min. The dynamic ranges of the detected signal are 105 and 106 for PMT and PD detectors, respectively. Compared to the previous detection system, the SNR ratio of frequency-domain detection was improved by nearly 103 through the addition of an RF amplifier and the utilization of programmable gain. The current system is being utilized in a clinical trial imaging suspected breast cancer tumors as detected by contrast MRI scans. PMID:23979460

  12. Breast cancer detection among young survivors of pediatric Hodgkin lymphoma with screening magnetic resonance imaging

    PubMed Central

    Tieu, Minh Thi; Cigsar, Candemir; Ahmed, Sameera; Ng, Andrea; Diller, Lisa; Millar, B-A; Crystal, Pavel; Hodgson, David C

    2014-01-01

    BACKGROUND Female survivors of pediatric Hodgkin lymphoma (HL) who have received chest radiotherapy are at increased risk of breast cancer. Guidelines for early breast cancer screening among these survivors are based on little data regarding clinical outcomes. This study reports outcomes of breast cancer screening with MRI and mammography (MMG) after childhood HL. METHODS We evaluated the results of breast MRI and MMG screening among 96 female survivors of childhood HL treated with chest radiotherapy. Outcomes measured included imaging sensitivity and specificity, breast cancer characteristics, and incidence of additional imaging and breast biopsy. RESULTS Median age at first screening was 30 years, and the median number of MRI screening rounds was 3. Ten breast cancers were detected in 9 women at a median age of 39 years (range, 24-43 years). Half were invasive and half were preinvasive. The median size of invasive tumors was 8 mm (range, 3-15 mm), and none had lymph node involvement. Sensitivity and specificity of the screening modalities were as follows: for MRI alone, 80% and 93.5%, respectively; MMG alone, 70% and 95%, respectively; both modalities combined, 100% and 88.6%, respectively. All invasive tumors were detected by MRI. Additional investigations were required in 52 patients, (54%), and 26 patients (27%) required breast biopsy, with 10 patients requiring more than 1 biopsy. CONCLUSIONS Screening including breast MRI with MMG has high sensitivity and specificity in pediatric HL survivors, with breast cancers detected at an early stage, although it is associated with a substantial rate of additional investigations. Cancer 2014;120:2507–2513. © 2014 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society. Screening female survivors of pediatric Hodgkin Lymphoma for breast cancer with MRI and mammography detected tumors at an earlier stage than prior studies of mammography alone, although a substantial proportion of

  13. Patellar segmentation from 3D magnetic resonance images using guided recursive ray-tracing for edge pattern detection

    NASA Astrophysics Data System (ADS)

    Cheng, Ruida; Jackson, Jennifer N.; McCreedy, Evan S.; Gandler, William; Eijkenboom, J. J. F. A.; van Middelkoop, M.; McAuliffe, Matthew J.; Sheehan, Frances T.

    2016-03-01

    The paper presents an automatic segmentation methodology for the patellar bone, based on 3D gradient recalled echo and gradient recalled echo with fat suppression magnetic resonance images. Constricted search space outlines are incorporated into recursive ray-tracing to segment the outer cortical bone. A statistical analysis based on the dependence of information in adjacent slices is used to limit the search in each image to between an outer and inner search region. A section based recursive ray-tracing mechanism is used to skip inner noise regions and detect the edge boundary. The proposed method achieves higher segmentation accuracy (0.23mm) than the current state-of-the-art methods with the average dice similarity coefficient of 96.0% (SD 1.3%) agreement between the auto-segmentation and ground truth surfaces.

  14. The design of a microfluidic biochip for the rapid, multiplexed detection of foodborne pathogens by surface plasmon resonance imaging

    NASA Astrophysics Data System (ADS)

    Zordan, Michael D.; Grafton, Meggie M. G.; Park, Kinam; Leary, James F.

    2010-02-01

    The rapid detection of foodborne pathogens is increasingly important due to the rising occurrence of contaminated food supplies. We have previously demonstrated the design of a hybrid optical device that has the capability to perform realtime surface plasmon resonance (SPR) and epi-fluorescence imaging. We now present the design of a microfluidic biochip consisting of a two-dimensional array of functionalized gold spots. The spots on the array have been functionalized with capture peptides that specifically bind E. coli O157:H7 or Salmonella enterica. This array is enclosed by a PDMS microfluidic flow cell. A magnetically pre-concentrated sample is injected into the biochip, and whole pathogens will bind to the capture array. The previously constructed optical device is being used to detect the presence and identity of captured pathogens using SPR imaging. This detection occurs in a label-free manner, and does not require the culture of bacterial samples. Molecular imaging can also be performed using the epi-fluorescence capabilities of the device to determine pathogen state, or to validate the identity of the captured pathogens using fluorescently labeled antibodies. We demonstrate the real-time screening of a sample for the presence of E. coli O157:H7 and Salmonella enterica. Additionally the mechanical properties of the microfluidic flow cell will be assessed. The effect of these properties on pathogen capture will be examined.

  15. Accurate three-dimensional registration of magnetic resonance images for detecting local changes in cartilage thickness

    NASA Astrophysics Data System (ADS)

    Cheng, Yuanzhi; Jin, Quan; Zhao, Jie; Guo, Changyong; Bai, Jing

    2011-04-01

    The purpose of this study is to develop a three-dimensional registration method for monitoring knee joint disease from magnetic resonance (MR) image data sets. A global optimization technique was used for identifying anatomically corresponding points of knee femur surfaces (bone cartilage interfaces). In a first pre-registration step, we used the principal axes transformation to correct for different knee joint positions and orientations in the MR scanner. In a second step, we presented a global search algorithm based on Lipschitz optimization theory. This technique can simultaneously determine the translation and rotation parameters through searching a six-dimensional space of Euclidean motion metrics (translation and rotation) after calculating the point correspondences. The point correspondences were calculated by using the Hungarian algorithm. The accuracy of registration was evaluated using 20 porcine knees. There were 300 corresponding landmark points over the 20 pig knees. We evaluated the registration accuracy by measuring the root-mean-square distance (RMSD) error of corresponding landmark points between two femur surfaces (two time-points). The results show that the average RMSD was 1.22 +/- 0.10 mm (SD) by the iterative closest point (ICP) method, 1.17 +/- 0.10 mm the by expectation-maximization-ICP method, 1.02 +/- 0.06 mm by the genetic method, and 0.93 +/- 0.04 mm by the proposed method. Compared with the other three registration approaches, the proposed method achieved the highest registration accuracy.

  16. Chemiluminescence resonance energy transfer imaging on magnetic particles for single-nucleotide polymorphism detection based on ligation chain reaction.

    PubMed

    Bi, Sai; Zhang, Zhipeng; Dong, Ying; Wang, Zonghua

    2015-03-15

    A novel ligation chain reaction (LCR) methodology for single-nucleotide polymorphism (SNP) detection was developed based on luminol-H2O2-horseradish peroxidase (HRP)-mimicking DNAzyme-fluorescein chemiluminescence resonance energy transfer (CRET) imaging on magnetic particles. For LCR, four unique target-complement probes (X and X(⁎), YG and Y(⁎)) for the amplification of K-ras (G12C) were designed by modifying G-quadruplex sequence at 3'-end of YG and fluorescein at 5'-end of Y(⁎). After the LCR, the resulting products of XYG/X(⁎)Y(⁎) with biotin-labeled X(⁎) were captured onto streptavidin-coated magnetic particles (SA-MPs) via specific biotin-SA interaction, which stimulated the CRET reaction from hemin/G-quadruplex-catalyzed luminol-H2O2 CL system to fluorescein. By collecting signals by a cooled low-light CCD, a CRET imaging method was proposed for visual detection and quantitative analysis of SNP. As low as 0.86fM mutant DNA was detected by this assay, and positive mutation detection was achieved with a wild-type to mutant ratio of 10,000:1. This high sensitivity and specificity could be attributed to not only the exponential amplification and excellent discrimination of LCR but also the employment of SA-MPs. SA-MPs ensured the feasibility of the proposed strategy, which also simplified the operations through magnetic separation and separated the reaction and detection procedures to improve sensitivity. The proposed LCR-CRET imaging strategy extends the application of signal amplification techniques to SNP detection, providing a promising platform for effective and high-throughput genetic diagnosis. PMID:25461149

  17. Design of a universal biointerface for sensitive, selective, and multiplex detection of biomarkers using surface plasmon resonance imaging.

    PubMed

    Shabani, Arghavan; Tabrizian, Maryam

    2013-10-21

    This paper reports on the sensitive, selective, and simultaneous detection of four protein biomarkers involved in metastasis of various cancers, namely Fas, angiopoietin-2 (Ang-2), human epidermal growth factor receptor 2 (HER2), and matrix metallopeptidase-9 (MMP-9) using an antibody-conjugated quantum dot (QD) chip and surface plasmon resonance imaging (SPRi) biosensors. Initially, a self-assembled monolayer film of l-cysteine, using glutaraldehyde as a linker and QDs as signal enhancement moieties, was employed to immobilize anti-Fas for the detection of Fas as a model protein in buffer. The biointerface was characterized using confocal microscopy, atomic force microscopy, and scanning electron microscopy to provide evidence of uniform surface coverage by the QDs. The SPRi signal was enhanced 100-fold to achieve a detection limit of 25 pg mL(-1) after applying biotinylated detection antibody-conjugate streptavidin-modified QDs. Secondly, this signal amplification strategy was applied to sequentially detect Fas, HER2, MMP-9, and Ang-2 at low concentrations on a protein-microprinted/gold-coated SPRi chip. The results showed the absence of cross-reactivity among these proteins and the feasibility of the approach for multiplex detection of biomarkers as required for the accurate diagnosis of various diseases. PMID:23954940

  18. Magnetic resonance imaging detects differences in migration between primary and immortalized neural stem cells

    PubMed Central

    Magnitsky, Sergey; Walton, Raquel M.; Wolfe, John H.; Poptani, Harish

    2008-01-01

    Rationale and Objectives The study was performed to evaluate the effect of MRI contrast agent (super paramagnetic iron oxide (SPIO)) on differentiation and migration of primary murine neural stem cells (NSCs) in comparison to a neural stem cell line (C17.2). Since detection of labeled cells depends on the concentration of SPIO particles per imaging voxel, the study was performed at various concentrations of SPIO particles to determine the concentration that could be used for in vivo detection of small clusters of grafted cells. Materials and Methods Murine primary NSCs or C17.2 cells were labeled with different concentrations of SPIO particles (0, 25, 100 and 250 μg Fe/ml) and in vitro assays were performed to assess cell differentiation. In vivo MRI was performed seven weeks after neonatal transplantation of labeled cells to evaluate the difference in migration capability of the two cell populations. Results Both the primary NSC’s and the C17.2 cells differentiated to similar number of neurons (Map2ab positive cells). Similar patterns of engraftment of C17. 2 cells were seen in transplanted mice regardless of the SPIO concentration used. In vivo MRI detection of grafted primary and C17.2 cells was only possible when cells were incubated with 100 μg/ml or higher concentration of SPIO. Extensive migration of C17.2 cells throughout the brain was observed, while the migration of the primary NSCs was more restricted. Conclusion Engraftment of primary NSC’s can be detected non-invasively by in vivo MRI and the presence of SPIO particles do not affect the viability, differentiation or engraftment pattern of the donor cells. PMID:18790399

  19. Interhemispheric neuroplasticity following limb deafferentation detected by resting-state functional connectivity magnetic resonance imaging (fcMRI) and functional magnetic resonance imaging (fMRI)

    PubMed Central

    Pawela, Christopher P.; Biswal, Bharat B.; Hudetz, Anthony G.; Li, Rupeng; Jones, Seth R.; Cho, Younghoon R.; Matloub, Hani S.; Hyde, James S.

    2009-01-01

    Functional connectivity magnetic resonance imaging (fcMRI) studies in rat brain show brain reorganization following peripheral nerve injury. Subacute neuroplasticity was observed two weeks following transection of the four major nerves of the brachial plexus. Direct functional magnetic resonance imaging (fMRI) stimulation of the intact radial nerve reveals an activation pattern in the forelimb regions of the sensory and motor cortices that is significantly different from that observed in normal rats. Results of this fMRI experiment were used to determine seed voxel regions for fcMRI analysis. Intrahemispheric connectivities in the sensorimotor forelimb representations in both hemispheres are largely unaffected by deafferentation, whereas substantial disruption of interhemispheric sensorimotor cortical connectivity occurs. In addition, significant intra- and interhemispheric changes in connectivities of thalamic nuclei were found. These are the central findings of the study. They could not have been obtained from fMRI studies alone—both fMRI and fcMRI are needed. The combination provides a general marker for brain plasticity. The rat visual system was studied in the same animals as a control. No neuroplastic changes in connectivities were found in the primary visual cortex upon forelimb deafferentation. Differences were noted in regions responsible for processing multisensory visual-motor information. This incidental discovery is considered to be significant. It may provide insight into phantom limb epiphenomena. PMID:19796693

  20. Noninvasive Detection of Macrophage-rich Atherosclerotic Plaque in Hyperlipidemic Rabbits using ‘Positive Contrast’ Magnetic Resonance Imaging

    PubMed Central

    Korosoglou, Grigorios; Weiss, Robert G.; Kedziorek, Dorota A.; Walczak, Piotr; Gilson, Wesley D.; Schär, Michael; Sosnovik, David; Kraitchman, Dara L.; Boston, Raymond C.; Bulte, Jeff W.M; Weissleder, Ralph; Stuber, Matthias

    2009-01-01

    Objectives To identify macrophage-rich atherosclerotic plaque non-invasively by the combined use of systemic administration of superparamagnetic nanoparticles with magnetic resonance imaging (MRI), using a positive contrast off-resonance imaging sequence (Inversion Recovery with ON-resonant water suppression: IRON). Background The sudden rupture of macrophage-rich atherosclerotic plaques can trigger the formation of an occlusive thrombus in coronary vessels, resulting in acute myocardial infarction. Therefore, a noninvasive technique that can identify macrophage-rich plaques and thereby assist with risk stratification of patients with atherosclerosis would be of great potential clinical utility. Methods Experiments were conducted on a clinical 3T MRI scanner in seven heritable hyperlipidemic and four control rabbits. Monocrystalline iron-oxide nanoparticles (MION)-47 were administrated intravenously (two doses of 250μmol Fe/kg), and animals underwent serial IRON-MRI before injection of the nanoparticles and serially after 1, 3 and 6 days. Results After administration of MION-47, a striking signal enhancement was found in areas of plaque only in hyperlipidemic rabbits. The magnitude of enhancement on MR-images had a high correlation with the number of macrophages determined by histology (p<0.001) and allowed for the detection of macrophage-rich plaque with high accuracy (AUC=0.92, SE=0.04, 95% CI=0.84-0.96, p<0.001). No significant signal enhancement was measured in remote areas without plaque by histology and in controls without atherosclerosis. Conclusion IRON-MRI in conjunction with superparamagnetic nanoparticles is a promising approach for the noninvasive evaluation of macrophage-rich, vulnerable plaques. PMID:18672170

  1. Cranial magnetic resonance imaging

    SciTech Connect

    Elster, A.D.

    1988-01-01

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

  2. Magnetic resonance imaging of radiation optic neuropathy

    SciTech Connect

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

    1990-10-15

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

  3. Brain 'Embolism' Detected by Magnetic Resonance Imaging During Percutaneous Mitral Balloon Commissurotomy

    SciTech Connect

    Rocha, Paulo; Qanadli, Salah D.; Strumza, Pierre; Kacher, Safia; Aberkane, Linda; Aubry, Pierre; Rigaud, Michel; Lacombe, Pascal; Raffestin, Bernadette

    1999-05-15

    Purpose: The common finding of thrombi between the bifoil balloons when they were extracted after mitral dilation prompted us to look for evidence of minor brain embolisms using the sensitive technique of BMRI (brain magnetic resonance T2-weighted imaging). Methods: BMRI was performed within 48 hr before and after a percutaneous mitral balloon commissurotomy (PMBC) in each of the 63 patients in this study. Results: There was evidence (hyperintensity foci: HI) of a previous asymptomatic brain embolism in 38 of 63 patients before PMBC and a new HI appeared in 18 of 63 patients after the procedure. New HI signals were found exclusively in the white matter in 8 of 18 patients and in only 3 of 18 were HI signs larger than 1 cm. One patient, with an HI signal >1 cm in the thalamus and another <1 cm in the brain stem, presented diplopia accompanied by other minor clinical signs. The differences in HI rate among four subgroups (1, older vs younger than 43 years; 2, sinus rhythm vs atrial fibrillation; 3, echo score <8 vs >8; 4, patients from western countries vs the others) were not statistically significant, probably because the number of patients in each subgroup was low. Patients in atrial fibrillation had slightly more (not significant) HI before PMBC (15/20, 75%) than patients in sinus rhythm (23/43, 53%), but after PMBC their HI frequencies were similar (atrial fibrillation: 5/20, 25%; sinus rhythm: 13/43, 30%). Conclusion: Brain microembolism is frequent during PMBC, but is often anatomically limited and free from clinical signs in most cases. Brain embolism seems to be related mainly to the procedure itself and not the features of the patient.

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

    NASA Astrophysics Data System (ADS)

    Belkić, Karen

    2004-06-01

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

  5. Self-assembled polymeric nanoparticles as new, smart contrast agents for cancer early detection using magnetic resonance imaging

    PubMed Central

    Mouffouk, Fouzi; Simão, Teresa; Dornelles, Daniel F; Lopes, André D; Sau, Pablo; Martins, Jorge; Abu-Salah, Khalid M; Alrokayan, Salman A; Rosa da Costa, Ana M; dos Santos, Nuno R

    2015-01-01

    Early cancer detection is a major factor in the reduction of mortality and cancer management cost. Here we developed a smart and targeted micelle-based contrast agent for magnetic resonance imaging (MRI), able to turn on its imaging capability in the presence of acidic cancer tissues. This smart contrast agent consists of pH-sensitive polymeric micelles formed by self-assembly of a diblock copolymer (poly(ethyleneglycol-b-trimethylsilyl methacrylate)), loaded with a gadolinium hydrophobic complex (tBuBipyGd) and exploits the acidic pH in cancer tissues. In vitro MRI experiments showed that tBuBipyGd-loaded micelles were pH-sensitive, as they turned on their imaging capability only in an acidic microenvironment. The micelle-targeting ability toward cancer cells was enhanced by conjugation with an antibody against the MUC1 protein. The ability of our antibody-decorated micelles to be switched on in acidic microenvironments and to target cancer cells expressing specific antigens, together with its high Gd(III) content and its small size (35–40 nm) reveals their potential use for early cancer detection by MRI. PMID:25565804

  6. Electrowetting on dielectric digital microfluidic platform with nanostructured biosensor interface for enhanced two-dimensional surface plasmon resonance imaging detection

    NASA Astrophysics Data System (ADS)

    Malic, Lidija

    The sensitive and specific detection of biomolecular interactions is at the heart of many routine analyses in fundamental research, medical diagnosis and environmental monitoring. In contrast to laborious and costly multiwell plate assays, recent years have witnessed a significant progress in miniaturized and integrated biosensors, such as surface plasmon resonance (SPR), tailored to these applications. While the design of various SPR biosensors has been described in literature, a robust, multichannel, low-cost and highly sensitive solution has not yet been presented. Specifically, an integrated system that can allow surface functionalization in array format, low-volume multichannel fluidic interfacing, and increased sensitivity is sought. This thesis describes a novel electro-wetting-on-dielectric (EWOD) digital microfluidic device with integrated nanostructured biosensor interface that addresses the aforementioned issues for enhanced surface plasmon resonance imaging (SPRi) detection. We have taken the opportunity of the most recent advances in microfabrication, nanotechnology and SPR technique to develop this integrated platform. EWOD device is employed for the dynamic immobilization of bioreceptors on SPRi biosensor surface in an array fashion from sub-muL volume solutions. Programmable EWOD electric interface allows the application of an electric field at the biosensor surface for active control of the immobilized probe density and orientation, enhancing SPRi detection. Two-dimensional SPRi detection is achieved by coupling the EWOD device to SPRi instrumentation. Parallel manipulation of individual droplets allows more efficient exploitation of the biosensor surface by separating different samples for simultaneous and selective SPRi detection. Periodic gold structures (nanoposts, nanogratings and nanogrooves) residing on a surface of glass and plastic substrates are investigated to improve the SPRi sensitivity. The corresponding electromagnetic field

  7. The preliminary study of immune superparamagnetic iron oxide nanoparticles for the detection of lung cancer in magnetic resonance imaging.

    PubMed

    Wan, Xinyuan; Song, Yuanqing; Song, Nijia; Li, Jiehua; Yang, Lie; Li, Yuan; Tan, Hong

    2016-01-01

    To improve the sensitive and specific detection of metastasis of lung cancer, this study fabricated immune superparamagnetic iron oxide nanoparticles (SPIONs) used in magnetic resonance (MR) immumoimaging. These SPIONs were coated with oleic acid and carboxymethyl dextran, and then conjugated to mouse anti-CD44v6 monoclonal antibody. The physicochemical properties of magnetic nanoparticles without monoclonal antibody were characterized by X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). The sizes of the nanoparticles were determined by dynamic light scattering measurements (DLS) and transmission electron microscope (TEM). Coated nanoparticles could well disperse in water with low dosage of CMD as the Fe/CMD ratio is 1/1 and 2/1 (w/w). Importantly, these SPIONs have relatively high saturation magnetization, as measured by vibrating sample magnetometer (VSM). They could efficiently become the transversal relaxation times (T2) contrast agent to improve detection limit through measured in vitro magnetic resonance imaging (MRI) and actively target human lung adenocarcinoma (A549) cells in vitro cell culture. Thus, these immune SPIONs are potentially useful for lung tumor-targeting diagnosis. PMID:26649917

  8. Detecting Vascular-Targeting Effects of the Hypoxic Cytotoxin Tirapazamine in Tumor Xenografts Using Magnetic Resonance Imaging

    SciTech Connect

    Bains, Lauren J.; Baker, Jennifer; Kyle, Alastair H.; Minchinton, Andrew I.; Reinsberg, Stefan A.

    2009-07-01

    Purpose: To determine whether vascular-targeting effects can be detected in vivo using magnetic resonance imaging (MRI). Methods and Materials: MR images of HCT-116 xenograft-bearing mice were acquired at 7 Tesla before and 24 hours after intraperitoneal injections of tirapazamine. Quantitative dynamic contrast-enhanced MRI analyses were performed to evaluate changes in tumor perfusion using two biomarkers: the volume transfer constant (K{sup trans}) and the initial area under the concentration-time curve (IAUC). We used novel implanted fiducial markers to obtain cryosections that corresponded to MR image planes from excised tumors; quantitative immunohistochemical mapping of tumor vasculature, perfusion, and necrosis enabled correlative analysis between these and MR images. Results: Conventional histological analysis showed lower vascular perfusion or greater amounts of necrosis in the central regions of five of eight tirapazamine-treated tumors, with three treated tumors showing no vascular dysfunction response. MRI data reflected this result, and a striking decrease in both K{sup trans} and IAUC values was seen with the responsive tumors. Retrospective evaluation of pretreatment MRI parameters revealed that those tumors that did not respond to the vascular-targeting effects of tirapazamine had significantly higher pretreatment K{sup trans} and IAUC values. Conclusions: MRI-derived parameter maps showed good agreement with histological tumor mapping. MRI was found to be an effective tool for noninvasively monitoring and predicting tirapazamine-mediated central vascular dysfunction.

  9. Relevance of magnetic resonance imaging for early detection and diagnosis of Alzheimer disease.

    PubMed

    Teipel, Stefan J; Grothe, Michel; Lista, Simone; Toschi, Nicola; Garaci, Francesco G; Hampel, Harald

    2013-05-01

    Hippocampus volumetry currently is the best-established imaging biomarker for AD. However, the effect of multicenter acquisition on measurements of hippocampus volume needs to be explicitly considered when it is applied in large clinical trials, for example by using mixed-effects models to take the clustering of data within centers into account. The marker needs further validation in respect of the underlying neurobiological substrate and potential confounds such as vascular disease, inflammation, hydrocephalus, and alcoholism, and with regard to clinical outcomes such as cognition but also to demographic and socioeconomic outcomes such as mortality and institutionalization. The use of hippocampus volumetry for risk stratification of predementia study samples will further increase with the availability of automated measurement approaches. An important step in this respect will be the development of a standard hippocampus tracing protocol that harmonizes the large range of presently available manual protocols. In the near future, regionally differentiated automated methods will become available together with an appropriate statistical model, such as multivariate analysis of deformation fields, or techniques such as cortical-thickness measurements that yield a meaningful metrics for the detection of treatment effects. More advanced imaging protocols, including DTI, DSI, and functional MRI, are presently being used in monocenter and first multicenter studies. In the future these techniques will be relevant for the risk stratification in phase IIa type studies (small proof-of-concept trials). By contrast, the application of the broader established structural imaging biomarkers, such as hippocampus volume, for risk stratification and as surrogate end point is already today part of many clinical trial protocols. However, clinical care will also be affected by these new technologies. Radiologic expert centers already offer “dementia screening” for well-off middle

  10. Magnetic resonance imaging - ultrasound fusion targeted biopsy outperforms standard approaches in detecting prostate cancer: A meta-analysis

    PubMed Central

    Jiang, Xuping; Zhang, Jiayi; Tang, Jingyuan; Xu, Zhen; Zhang, Wei; Zhang, Qing; Guo, Hongqian; Zhou, Weimin

    2016-01-01

    The aim of the present study was to determine whether magnetic resonance imaging - ultrasound (MRI-US) fusion prostate biopsy is superior to systematic biopsy for making a definitive diagnosis of prostate cancer. The two strategies were also compared regarding their ability to detect clinically significant and insignificant prostate cancer. A literature search was conducted through the PubMed, EMBASE and China National Knowledge Infrastructure databases using appropriate search terms. A total of 3,415 cases from 21 studies were included in the present meta-analysis. Data were expressed as relative risk (RR) and 95% confidence interval. The results revealed that MRI-US fusion biopsy achieved a higher rate of overall prostate cancer detection compared with systematic biopsy (RR=1.09; P=0.047). Moreover, MRI-US fusion biopsy detected more clinically significant cancers compared with systematic biopsy (RR=1.22; P<0.01). It is therefore recommended that multi-parametric MRI-US is performed in men suspected of having prostate cancer to optimize the detection of clinically significant disease, while reducing the burden of biopsies. PMID:27446568

  11. 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

  12. 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.

  13. In Vivo Detection of Activated Platelets Allows Characterizing Rupture of Atherosclerotic Plaques with Molecular Magnetic Resonance Imaging in Mice

    PubMed Central

    Wiens, Kristina; Neudorfer, Irene; Zirlik, Andreas; Meissner, Mirko; Tilly, Peg; Charles, Anne-Laure; Bode, Christoph; Peter, Karlheinz; Fabre, Jean-Etienne

    2012-01-01

    Background Early and non-invasive detection of platelets on micro atherothrombosis provides a means to identify unstable plaque and thereby allowing prophylactic treatment towards prevention of stroke or myocardial infarction. Molecular magnetic resonance imaging (mMRI) of activated platelets as early markers of plaque rupture using targeted contrast agents is a promising strategy. In this study, we aim to specifically image activated platelets in murine atherothrombosis by in vivo mMRI, using a dedicated animal model of plaque rupture. Methods An antibody targeting ligand-induced binding sites (LIBS) on the glycoprotein IIb/IIIa-receptor of activated platelets was conjugated to microparticles of iron oxide (MPIO) to form the LIBS-MPIO contrast agent causing a signal-extinction in T2*-weighted MRI. ApoE−/− mice (60 weeks-old) were fed a high fat diet for 5 weeks. Using a small needle, the surface of their carotid plaques was scratched under blood flow to induce atherothrombosis. In vivo 9.4 Tesla MRI was performed before and repetitively after intravenous injection of either LIBS-MPIO versus non-targeted-MPIO. Results LIBS-MPIO injected animals showed a significant signal extinction (p<0.05) in MRI, corresponding to the site of plaque rupture and atherothrombosis in histology. The signal attenuation was effective for atherothrombosis occupying ≥2% of the vascular lumen. Histology further confirmed significant binding of LIBS-MPIO compared to control-MPIO on the thrombus developing on the surface of ruptured plaques (p<0.01). Conclusion in vivo mMRI detected activated platelets on mechanically ruptured atherosclerotic plaques in ApoE−/− mice with a high sensititvity. This imaging technology represents a unique opportunity for noninvasive detection of atherothrombosis and the identification of unstable atherosclerotic plaques with the ultimate promise to prevent strokes and myocardial infarctions. PMID:23028736

  14. Multifunctional iron platinum stealth immunomicelles: targeted detection of human prostate cancer cells using both fluorescence and magnetic resonance imaging

    PubMed Central

    Huber, Dale L.; Monson, Todd C.; Ali, Abdul-Mehdi S.; Bisoffi, Marco; Sillerud, Laurel O.

    2011-01-01

    Superparamagnetic iron oxide nanoparticles (SPIONs) are the most common type of contrast agents used in contrast agent-enhanced magnetic resonance imaging (MRI). Still, there is a great deal of room for improvement, and nanoparticles with increased MRI relaxivities are needed to increase the contrast enhancement in MRI applied to various medical conditions including cancer. We report the synthesis of superparamagnetic iron platinum nanoparticles (SIPPs) and subsequent encapsulation using PEGylated phospholipids to create stealth immunomicelles (DSPE-SIPPs) that can be specifically targeted to human prostate cancer cell lines and detected using both MRI and fluorescence imaging. SIPP cores and DSPE-SIPPs were 8.5 ± 1.6 nm and 42.9 ± 8.2 nm in diameter, respectively, and the SIPPs had a magnetic moment of 120 A m2/kg iron. J591, a monoclonal antibody against prostate specific membrane antigen (PSMA), was conjugated to the DSPE-SIPPs (J591-DSPE-SIPPs), and specific targeting of J591-DSPE-SIPPs to PSMA-expressing human prostate cancer cell lines was demonstrated using fluorescence confocal microscopy. The transverse relaxivity of the DSPE-SIPPs, measured at 4.7 Tesla, was 300.6 ± 8.5 s−1 mM−1, which is 13-fold better than commercially available SPIONs (23.8 ± 6.9 s−1 mM−1) and ~3-fold better than reported relaxivities for Feridex® and Resovist®. Our data suggest that J591-DSPE-SIPPs specifically target human prostate cancer cells in vitro, are superior contrast agents in T2-weighted MRI, and can be detected using fluorescence imaging. To our knowledge, this is the first report on the synthesis of multifunctional SIPP micelles and using SIPPs for the specific detection of prostate cancer. PMID:22121333

  15. Comparison of Magnetic Resonance Imaging and Serum Biomarkers for Detection of Human Pluripotent Stem Cell-Derived Teratomas

    PubMed Central

    Riegler, Johannes; Ebert, Antje; Qin, Xulei; Shen, Qi; Wang, Mouer; Ameen, Mohamed; Kodo, Kazuki; Ong, Sang-Ging; Lee, Won Hee; Lee, Grace; Neofytou, Evgenios; Gold, Joseph D.; Connolly, Andrew J.; Wu, Joseph C.

    2016-01-01

    Summary The use of cells derived from pluripotent stem cells (PSCs) for regenerative therapies confers a considerable risk for neoplastic growth and teratoma formation. Preclinical and clinical assessment of such therapies will require suitable monitoring strategies to understand and mitigate these risks. Here we generated human-induced pluripotent stem cells (iPSCs), selected clones that continued to express reprogramming factors after differentiation into cardiomyocytes, and transplanted these cardiomyocytes into immunocompromised rat hearts post-myocardial infarction. We compared magnetic resonance imaging (MRI), cardiac ultrasound, and serum biomarkers for their ability to delineate teratoma formation and growth. MRI enabled the detection of teratomas with a volume >8 mm3. A combination of three plasma biomarkers (CEA, AFP, and HCG) was able to detect teratomas with a volume >17 mm3 and with a sensitivity of more than 87%. Based on our findings, a combination of serum biomarkers with MRI screening may offer the highest sensitivity for teratoma detection and tracking. PMID:26777057

  16. Hybrid surface platform for the simultaneous detection of proteins and DNAs using a surface plasmon resonance imaging sensor.

    PubMed

    Ladd, Jon; Taylor, Allen D; Piliarik, Marek; Homola, Jiri; Jiang, Shaoyi

    2008-06-01

    In this work, we present a novel surface and assay for the simultaneous detection of DNA and protein analytes on a surface plasmon resonance (SPR) imaging sensor. A mixed DNA/oligo (ethylene glycol) (OEG) self-assembled monolayer (SAM) is created using a microarrayer. Thiol-modified single-stranded DNA sequences are spotted onto a gold-coated glass substrate. Backfilling with an OEG-modified alkanethiol creates a protein-resistant surface background. Antibodies conjugated to complementary single-stranded DNA sequences are immobilized on the surface through DNA hybridization. By converting only part of the DNA array into a protein array, simultaneous detections of DNA and protein analytes are possible. A model system of two cDNA sequences and two human pregnancy hormones are used to demonstrate the assay. No cross-reactivity was observed between DNA or protein analytes and nontargeted immobilized cDNA sequence or antibodies. A response from a detection of a single analyte in a mixture of protein and DNA analytes corresponds well with that of a single-analyte solution. PMID:18457413

  17. Comparison of transrectal photoacoustic, Doppler, and magnetic resonance imaging for prostate cancer detection

    NASA Astrophysics Data System (ADS)

    Ishihara, Miya; Horiguchi, Akio; Shinmoto, Hiroshi; Tsuda, Hitoshi; Irisawa, Kaku; Wada, Takatsugu; Asano, Tomohiko

    2016-03-01

    Transrectal ultrasonography (TRUS) is the most popular imaging modality for diagnosing and treating prostate cancer. TRUS-guided prostate biopsy is mandatory for the histological diagnosis of patients with elevated serum prostatespecific antigen (PSA), but its diagnostic accuracy is not satisfactory due to TRUS's low resolution. As a result, a considerable number of patients are required to undergo an unnecessary repeated biopsy. Photoacoustic imaging (PAI) can be used to provide microvascular network imaging using hemoglobin as an intrinsic, optical absorption molecule. We developed an original TRUS-type PAI probe consisting of a micro-convex array transducer with an optical illumination system to provide superimposed PAI and ultrasound images. TRUS-type PAI has the advantage of having much higher resolution and greater contrast than does Doppler TRUS. The purpose of this study was to demonstrate the clinical feasibility of the transrectal PAI system. We performed a clinical trial to compare the image of the cancerous area obtained by transrectal PAI with that obtained by TRUS Doppler during prostate biopsy. The obtained prostate biopsy cores were stained with anti-CD34 antibodies to provide a microvascular distribution map. We also confirmed its consistency with PAI and pre-biopsy MRI findings. Our study demonstrated that transrectal identification of tumor angiogenesis under superimposed photoacoustic and ultrasound images was easier than that under TRUS alone. We recognized a consistent relationship between PAI and MRI findings in most cases. However, there were no correspondences in some cases.

  18. Sodium-23 magnetic resonance imaging has potential for improving penumbra detection but not for estimating stroke onset time.

    PubMed

    Wetterling, Friedrich; Gallagher, Lindsay; Mullin, Jim; Holmes, William M; McCabe, Chris; Macrae, I Mhairi; Fagan, Andrew J

    2015-01-01

    Tissue sodium concentration increases in irreversibly damaged (core) tissue following ischemic stroke and can potentially help to differentiate the core from the adjacent hypoperfused but viable penumbra. To test this, multinuclear hydrogen-1/sodium-23 magnetic resonance imaging (MRI) was used to measure the changing sodium signal and hydrogen-apparent diffusion coefficient (ADC) in the ischemic core and penumbra after rat middle cerebral artery occlusion (MCAO). Penumbra and core were defined from perfusion imaging and histologically defined irreversibly damaged tissue. The sodium signal in the core increased linearly with time, whereas the ADC rapidly decreased by >30% within 20 minutes of stroke onset, with very little change thereafter (0.5-6 hours after MCAO). Previous reports suggest that the time point at which tissue sodium signal starts to rise above normal (onset of elevated tissue sodium, OETS) represents stroke onset time (SOT). However, extrapolating core data back in time resulted in a delay of 72 ± 24 minutes in OETS compared with actual SOT. At the OETS in the core, penumbra sodium signal was significantly decreased (88 ± 6%, P=0.0008), whereas penumbra ADC was not significantly different (92 ± 18%, P=0.2) from contralateral tissue. In conclusion, reduced sodium-MRI signal may serve as a viability marker for penumbra detection and can complement hydrogen ADC and perfusion MRI in the time-independent assessment of tissue fate in acute stroke patients. PMID:25335803

  19. Sodium-23 magnetic resonance imaging has potential for improving penumbra detection but not for estimating stroke onset time

    PubMed Central

    Wetterling, Friedrich; Gallagher, Lindsay; Mullin, Jim; Holmes, William M; McCabe, Chris; Macrae, I Mhairi; Fagan, Andrew J

    2015-01-01

    Tissue sodium concentration increases in irreversibly damaged (core) tissue following ischemic stroke and can potentially help to differentiate the core from the adjacent hypoperfused but viable penumbra. To test this, multinuclear hydrogen-1/sodium-23 magnetic resonance imaging (MRI) was used to measure the changing sodium signal and hydrogen-apparent diffusion coefficient (ADC) in the ischemic core and penumbra after rat middle cerebral artery occlusion (MCAO). Penumbra and core were defined from perfusion imaging and histologically defined irreversibly damaged tissue. The sodium signal in the core increased linearly with time, whereas the ADC rapidly decreased by >30% within 20 minutes of stroke onset, with very little change thereafter (0.5–6 hours after MCAO). Previous reports suggest that the time point at which tissue sodium signal starts to rise above normal (onset of elevated tissue sodium, OETS) represents stroke onset time (SOT). However, extrapolating core data back in time resulted in a delay of 72±24 minutes in OETS compared with actual SOT. At the OETS in the core, penumbra sodium signal was significantly decreased (88±6%, P=0.0008), whereas penumbra ADC was not significantly different (92±18%, P=0.2) from contralateral tissue. In conclusion, reduced sodium-MRI signal may serve as a viability marker for penumbra detection and can complement hydrogen ADC and perfusion MRI in the time-independent assessment of tissue fate in acute stroke patients. PMID:25335803

  20. Magnetic Resonance Imaging Duodenoscope.

    PubMed

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

    2013-12-01

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

  1. The current and future role of magnetic resonance imaging in prostate cancer detection and management

    PubMed Central

    Radtke, Jan Philipp; Teber, Dogu; Hohenfellner, Markus

    2015-01-01

    Purpose Accurate detection of clinically significant prostate cancer (PC) and correct risk attribution are essential to individually counsel men with PC. Multiparametric MRI (mpMRI) facilitates correct localization of index lesions within the prostate and MRI-targeted prostate biopsy (TPB) helps to avoid the shortcomings of conventional biopsy such as false-negative results or underdiagnosis of aggressive PC. In this review we summarize the different sequences of mpMRI, characterize the possibilities of incorporating MRI in the biopsy workflow and outline the performance of targeted and systematic cores in significant cancer detection. Furthermore, we outline the potential of MRI in patients undergoing active surveillance (AS) and in the pre-operative setting. Materials and methods An electronic MEDLINE/PubMed search up to February 2015 was performed. English language articles were reviewed for inclusion ability and data were extracted, analyzed and summarized. Results Targeted biopsies significantly outperform conventional systematic biopsies in the detection of significant PC and are not inferior when compared to transperineal saturation biopsies. MpMRI can detect index lesions in app. 90% of cases as compared to prostatectomy specimen. The diagnostic performance of biparametric MRI (T2w + DWI) is not inferior to mpMRI, offering options to diminish cost- and time-consumption. Since app 10% of significant lesions are still MRI-invisible, systematic cores seem to be necessary. In-bore biopsy and MRI/TRUS-fusion-guided biopsy tend to be superior techniques compared to cognitive fusion. In AS, mpMRI avoids underdetection of significant PC and confirms low-risk disease accurately. In higher-risk disease, pre-surgical MRI can change the clinically-based surgical plan in up to a third of cases. Conclusions mpMRI and targeted biopsies are able to detect significant PC accurately and mitigate insignificant PC detection. As long as the negative predictive value (NPV) is

  2. Multiplex surface plasmon resonance biosensing and its transferability towards imaging nanoplasmonics for detection of mycotoxins in barley.

    PubMed

    Joshi, Sweccha; Segarra-Fas, Anna; Peters, Jeroen; Zuilhof, Han; van Beek, Teris A; Nielen, Michel W F

    2016-02-21

    A 6-plex competitive inhibition immunoassay for mycotoxins in barley was developed on a prototype portable nanostructured imaging surface plasmon resonance (iSPR) instrument, also referred to as imaging nanoplasmonics. As a benchmark for the prototype nanoplasmonics instrument, first a double 3-plex assay was developed for the detection of deoxynivalenol (DON), zearalenone (ZEA), T-2 toxin (T-2), ochratoxin A (OTA), fumonisin B1 (FB1) and aflatoxin B1 (AFB1) using a well-established benchtop SPR instrument and two biosensor chips. To this end, ovalbumin (OVA) conjugates of mycotoxins were immobilized on the chip via amine coupling. The SPR response was then recorded upon injection of a mixture of antibodies at a fixed concentration and the sample (or matrix-matched standard) over a chip with immobilized mycotoxin-OVA conjugates. The chips were regenerated after each sample using 10 mM HCl and 20 mM NaOH and could be used for at least 60 cycles. The limits of detection in barley (in μg kg(-1)) were determined to be 26 for DON, 6 for ZEA, 0.6 for T-2, 3 for OTA, 2 for FB1 and 0.6 for AFB1. Preliminary in-house validation showed that DON, T-2, ZEA and FB1 can be detected at the European Union regulatory limits, while for OTA and AFB1 sensitivities should be improved. Furthermore, measurement of naturally contaminated barley showed that the assay can be used as a semi-quantitative screening method for mycotoxins prior to liquid chromatography tandem mass spectrometry (LC-MS/MS). Finally, using the same bio-reagents the assay was transferred to a 6-plex format in the nanoplasmonics instrument and subsequently the two assays were compared. Although less sensitive, the 6-plex portable iSPR assay still allowed detection of DON, T-2, ZEA and FB1 at relevant levels. Therefore, the prototype iSPR shows potential for future applications in rapid in-field and at-line screening of multiple mycotoxins. PMID:26763589

  3. Coronary Computed Tomography and Magnetic Resonance Imaging

    PubMed Central

    Kantor, Birgit; Nagel, Eike; Schoenhagen, Paul; Barkhausen, Jörg; Gerber, Thomas C.

    2009-01-01

    Cardiac computed tomography and magnetic resonance are relatively new imaging modalities that can exceed the ability of established imaging modalities to detect present pathology or predict patient outcomes. Coronary calcium scoring may be useful in asymptomatic patients at intermediate risk. Computed tomographic coronary angiography is a first-line indication to evaluate congenitally abnormal coronary arteries and, along with stress magnetic resonance myocardial perfusion imaging, is useful in symptomatic patients with nondiagnostic conventional stress tests. Cardiac magnetic resonance is indicated for visualizing cardiac structure and function, and delayed enhancement magnetic resonance is a first-line indication for assessing myocardial viability. Imaging plaque and molecular mechanisms related to plaque rupture holds great promise for the presymptomatic detection of patients at risk for coronary events but is not yet suitable for routine clinical use. PMID:19269527

  4. Electron Paramagnetic Resonance: a tool for in situ detection, imaging and dating of biosignatures in primitive organic matter

    NASA Astrophysics Data System (ADS)

    Gourier, D.; Binet, L.; Vezin, H.

    2012-04-01

    Electron Paramagnetic Resonance (EPR) spectroscopy and imaging are based on the interaction of a microwave electromagnetic field (typically in the GHz range) with electron spins in presence of an external magnetic field. Contrary to UV-visible and Infrared light, microwave radiation can penetrate in most non conducting materials, so that EPR is sensitive to the bulk (and not to the surface) of samples. All the paramagnetic defects, impurities, point defects in the mineral matrix, radicals in carbonaceous matter of an ancient rock can be detected by this technique. As the most ancient traces of life, as old as 3.5 Gy, are recorded as carbonaceous microstructures in siliceous sedimentary structures (cherts), the radical defects of these microstructures can be probed in situ without sample preparation. By using continuous-wave EPR, the fossilized carbonaceous matter can be mapped at the sub-millimeter scale (EPR imaging)[1], and can be dated with respect to the host rock (evolution of the EPR lineshape)[2]. Thus this method could be used for contamination detection (endolithic bacteria, infiltration etc…). By using pulsed-EPR spectroscopy (instead of continuous wave), nuclear magnetic transitions of elements in and around radicals can be detected with a high resolution and sensitivity. We show that specific nuclear transitions for hydrogen (1H and 2D) and 13C (and other nuclei such as 29Si and 31P) can be identified in extraterrestrial carbonaceous matter (meteorites) and in Precambrian and younger cherts. These pulsed techniques provide molecular scale biosignatures for primitive life detection and internal probes to study the history of organic matter in the early solar system [3,4]. Paramagnetic biosignatures are not limited to the organic component of cherts. Specific EPR biosignatures of metal ions can be detected in biominerals such as MnO2 [5] or in molecular V4+ complexes [6]. EPR is thus a potential technique for the search of primitive life on Earth and

  5. Study of Immobilization Procedure on Silver Nanolayers and Detection of Estrone with Diverged Beam Surface Plasmon Resonance (SPR) Imaging

    PubMed Central

    Karabchevsky, Alina; Tsapovsky, Lev; Marks, Robert S.; Abdulhalim, Ibrahim

    2013-01-01

    An immobilization protocol was developed to attach receptors on smooth silver thin films. Dense and packed 11-mercaptoundecanoic acid (11-MUA) was used to avoid uncontrolled sulfidization and harmful oxidation of silver nanolayers. N,N'-dicyclohexylcarbodiimide (DCC) and N-hydroxysuccinimide (NHS) were added to make the silver surfaces reactive. A comparative study was carried out with different immersion times of silver samples in 11-MUA solutions with different concentrations to find the optimum conditions for immobilization. The signals, during each step of the protocol, were analyzed with a refractometer based on the surface plasmon resonance (SPR) effect and luminescence techniques. Molecular interactions at the surfaces between the probe and target at the surface nanolayer shift the SPR signal, thus indicating the presence of the substance. To demonstrate specific biosensing, rabbit anti-estrone polyclonal immunoglobulin G (IgG) antibody was immobilized through a linker on 47 nm silver layer deposited on SF11 glass. At the final stage, the representative endocrine disruptor—estrone—was attached and detected in deionized water with a diverging beam SPR imaging sensor. PMID:25587405

  6. More Specific Signal Detection in Functional Magnetic Resonance Imaging by False Discovery Rate Control for Hierarchically Structured Systems of Hypotheses

    PubMed Central

    Schildknecht, Konstantin; Tabelow, Karsten; Dickhaus, Thorsten

    2016-01-01

    Signal detection in functional magnetic resonance imaging (fMRI) inherently involves the problem of testing a large number of hypotheses. A popular strategy to address this multiplicity is the control of the false discovery rate (FDR). In this work we consider the case where prior knowledge is available to partition the set of all hypotheses into disjoint subsets or families, e. g., by a-priori knowledge on the functionality of certain regions of interest. If the proportion of true null hypotheses differs between families, this structural information can be used to increase statistical power. We propose a two-stage multiple test procedure which first excludes those families from the analysis for which there is no strong evidence for containing true alternatives. We show control of the family-wise error rate at this first stage of testing. Then, at the second stage, we proceed to test the hypotheses within each non-excluded family and obtain asymptotic control of the FDR within each family at this second stage. Our main mathematical result is that this two-stage strategy implies asymptotic control of the FDR with respect to all hypotheses. In simulations we demonstrate the increased power of this new procedure in comparison with established procedures in situations with highly unbalanced families. Finally, we apply the proposed method to simulated and to real fMRI data. PMID:26914144

  7. Reversible hippocampal lesions detected on magnetic resonance imaging in two cases of transient selective amnesia for simple machine operation.

    PubMed

    Yamaoka, Yumiko; Bandoh, Mitsuaki; Kawai, Kensuke

    2016-08-01

    We report two extremely rare cases involving the development of transient selective retrograde amnesia for simple machine operation lasting for several hours. A 61-year-old male taxi driver suddenly became unable to operate a taximeter, and a 66-year-old female janitor suddenly became unable to use a fax machine. They could precisely recount their episodes to others both during and after the attacks, and their memories during their attacks corresponded to the memory of the witness and the medical records of the doctor, respectively. Therefore, it appears that these individuals remained alert and did not develop anterograde amnesia during their attacks. On day 4, they underwent high-resolution magnetic resonance imaging (MRI), and diffusion-weighted MRI with 2-mm section thickness revealed small high-intensity signal lesions in the left hippocampal cornu ammonis area 1 (CA1) region. However, these lesions disappeared during the chronic phase. This is the first report describing lesions detected by MRI in patients with transient selective amnesia without anterograde amnesia. Reversible damage to the hippocampal CA1 region may cause transient selective amnesia by impairing the retrieval of relevant memories. PMID:27367337

  8. Comparison of different electrocardiographic scoring systems for detection of any previous myocardial infarction as assessed with cardiovascular magnetic resonance imaging.

    PubMed

    Jaarsma, Caroline; Bekkers, Sebastiaan C; Haidari, Zaki; Smulders, Martijn W; Nelemans, Patricia J; Gorgels, Anton P; Crijns, Harry J; Wildberger, Joachim E; Schalla, Simon

    2013-10-15

    Although electrocardiography is frequently used as an initial test to detect or rule out previous myocardial infarction (MI), the diagnostic performance of commonly used electrocardiographic scoring systems is not well described. We aimed to determine the diagnostic accuracy of (1) the Universal Definition, (2) Minnesota ECG Code (MC), (3) Selvester QRS Score, and (4) assessment by cardiologists using late gadolinium enhancement cardiovascular magnetic resonance imaging as the reference standard. Additionally, the effect of electrocardiographic patterns and infarct characteristics on detecting previous MI was evaluated. The 3-month follow-up electrocardiograms of 78 patients with first-time reperfused ST elevation MI were pooled with electrocardiograms of 36 healthy controls. All 114 electrocardiograms were randomly analyzed, blinded to clinical and LGE-CMR data. The sensitivity of the Universal Definition, MC, Selvester QRS Score, and cardiologists to detect previous MI was 33%, 79%, 90%, and 67%, respectively; specificity 97%, 72%, 31%, and 89%, respectively; diagnostic accuracy 54%, 77%, 71%, and 74%, respectively. Probability of detecting MI by cardiologists increased with an increasing number (odds ratio [OR] 2.00, 95% confidence interval [CI] 1.30 to 3.09), width (OR 1.02, 95% CI 1.01 to 1.03), and depth (OR 1.16, 95% CI 1.07 to 1.27) of Q waves as well as increasing infarct size (OR 1.15, 95% CI 1.06 to 1.25) and transmurality (OR 1.05, 95% CI 1.01 to 1.08; p <0.05 for all). The time-consuming MC and rapid visual assessment by cardiologists achieved the best and similar diagnostic accuracies to detect previous MI. The diagnostic performance of all 4 electrocardiographic scoring systems was modest and related to the number, depth, and width of Q waves as well as increasing infarct size and transmurality. In conclusion, the exclusion of a previous MI based solely on electrocardiographic findings should be done with caution. Future studies are needed to define

  9. Accessible magnetic resonance imaging.

    PubMed

    Kaufman, L; Arakawa, M; Hale, J; Rothschild, P; Carlson, J; Hake, K; Kramer, D; Lu, W; Van Heteren, J

    1989-10-01

    The cost of magnetic resonance imaging (MRI) is driven by magnetic field strength. Misperceptions as to the impact of field strength on performance have led to systems that are more expensive than they need to be. Careful analysis of all the factors that affect diagnostic quality lead to the conclusion that field strength per se is not a strong determinant of system performance. Freed from the constraints imposed by high-field operation, it is possible to exploit a varied set of opportunities afforded by low-field operation. In addition to lower costs and easier siting, we can take advantage of shortened T1 times, higher contrast, reduced sensitivity to motion, and reduced radiofrequency power deposition. These conceptual advantages can be made to coalesce onto practical imaging systems. We describe a low-cost MRI system that utilizes a permanent magnet of open design. Careful optimization of receiving antennas and acquisition sequences permit performance levels consistent with those needed for an effective diagnostic unit. Ancillary advantages include easy access to the patient, reduced claustrophobia, quiet and comfortable operation, and absence of a missile effect. The system can be sited in 350 sq ft and consumes a modest amount of electricity. MRI equipment of this kind can widen the population base than can access this powerful and beneficial diagnostic modality. PMID:2640910

  10. Functional magnetic resonance imaging.

    PubMed

    Buchbinder, Bradley R

    2016-01-01

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

  11. Multiparametric Magnetic Resonance Imaging and Image-Guided Biopsy to Detect Seminal Vesicle Invasion by Prostate Cancer

    PubMed Central

    Raskolnikov, Dima; George, Arvin K.; Rais-Bahrami, Soroush; Turkbey, Baris; Shakir, Nabeel A.; Okoro, Chinonyerem; Rothwax, Jason T.; Walton-Diaz, Annerleim; Siddiqui, M. Minhaj; Su, Daniel; Stamatakis, Lambros; Merino, Maria J.; Wood, Bradford J.; Choyke, Peter L.

    2014-01-01

    Abstract Objectives: To evaluate the correlation between multiparametric prostate MRI (MP-MRI) suspicion for seminal vesicle invasion (SVI) by prostate cancer (PCa) and pathology on MRI/ultrasound (US) fusion-guided biopsy. Patients and Methods: From March 2007 to June 2013, 822 patients underwent MP-MRI at 3 Tesla and MRI/US fusion-guided biopsy. Of these, 25 patients underwent targeted biopsy of the seminal vesicles (SVs). In six patients, bilateral SVI was suspected, resulting in 31 samples. MP-MRI findings that triggered these SV biopsies were scored as low, moderate, or high suspicion for SVI based on the degree of involvement on MRI. Correlative prostate biopsy and radical prostatectomy (RP) pathology were reviewed by a single genitourinary pathologist. Results: At the time of MP-MRI, the median age was 64 years with a median prostate-specific antigen of 10.74 ng/mL. Of the 31 SV lesions identified, MP-MRI suspicion scores of low, moderate, and high were assigned to 3, 19, and 9 lesions, respectively. MRI/US fusion-guided biopsy detected SVI in 20/31 (65%) of cases. For the four patients who underwent RP after a preoperative assessment of SVI, biopsy pathology and RP pathology were concordant in all cases. Conclusions: As this technology becomes more available, MP-MRI and MRI/US fusion-guided biopsy may play a role in the preoperative staging for PCa. Future work will determine if improved preoperative staging leads to better surgical outcomes. PMID:25010361

  12. Submarine UXO Detection Using Resonance Scattering Sonar

    NASA Astrophysics Data System (ADS)

    Gritto, R.; Korneev, V. A.; Johnson, L. R.

    2010-12-01

    Resonance scattered waves from a dataset collected in a pond setting were utilized to detect and characterize unexploded ordnance (UXO) located proud off the bottom sediments. Furthermore, it was investigated whether UXO can be characterized by their size and filler velocities and whether medium velocities can be derived from the field data. Analysis of the field data was supported by numerical modeling. It was found that resonance scattered waves were present in all numerical data and in the field cases of a proud sphere and a buried cylinder. In all other cases of proud UXO the field data revealed frequency dependent scattered waves that were part of the direct reflected waves. Imaging UXO with monochromatic data produces surprisingly good results considering that in most investigated cases a small fraction of the data with very low amplitudes were used in comparison to data typically used for Kirchhoff migration or SAS imaging. The images derived from resonance scattered waves were generated by data obtained from narrow passbands throughout the whole frequency spectrum such that different parts of the UXO can be illumination separately. Range resolution is reduced when imaging is done with monochromatic signals. However, the image resolution can be dramatically improved by adding data from different azimuth as was demonstrated for the cases of a proud sphere and bomb. A suite of results ranging from numerical calculations to field data will be presented to show how the properties of resonance scattering can be utilized to detect, locate and characterize an UXO in littoral environments.

  13. A cerium oxide nanoparticle-based device for the detection of chronic inflammation via optical and magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Kaittanis, Charalambos; Santra, Santimukul; Asati, Atul; Perez, J. Manuel

    2012-03-01

    Monitoring of microenvironmental parameters is critical in healthcare and disease management. Harnessing the antioxidant activity of nanoceria and the imaging capabilities of iron oxide nanoparticles in a device setup, we were able to image changes in the device's aqueous milieu. The device was able to convey and process changes in the microenvironment's pH and reactive oxygen species' concentration, distinguishing physiological from abnormal levels. As a result under physiological and transient inflammatory conditions, the device's fluorescence and magnetic resonance signals, emanating from multimodal iron oxide nanoparticles, were similar. However, under chronic inflammatory conditions that are usually associated with high local concentrations of reactive oxygen species and pH decrease, the device's output was considerably different. Specifically, the device's fluorescence emission significantly decreased, while the magnetic resonance signal T2 increased. Further studies identified that the changes in the device's output are attributed to inactivation of the sensing component's nanoceria that prevents it from successfully scavenging the generated free radicals. Interestingly, the buildup of free radical excess led to polymerization of the iron oxide nanoparticle's coating, with concomitant formation of micron size aggregates. Our studies indicate that a nanoceria-based device can be utilized for the monitoring of pro-inflammatory biomarkers, having important applications in the management of numerous ailments while eliminating nanoparticle toxicity issues.Monitoring of microenvironmental parameters is critical in healthcare and disease management. Harnessing the antioxidant activity of nanoceria and the imaging capabilities of iron oxide nanoparticles in a device setup, we were able to image changes in the device's aqueous milieu. The device was able to convey and process changes in the microenvironment's pH and reactive oxygen species' concentration

  14. Multiparametric magnetic resonance imaging: Current role in prostate cancer management.

    PubMed

    Ueno, Yoshiko; Tamada, Tsutomu; Bist, Vipul; Reinhold, Caroline; Miyake, Hideaki; Tanaka, Utaru; Kitajima, Kazuhiro; Sugimura, Kazuro; Takahashi, Satoru

    2016-07-01

    Digital rectal examination, serum prostate-specific antigen screening and transrectal ultrasound-guided biopsy are conventionally used as screening, diagnostic and surveillance tools for prostate cancer. However, they have limited sensitivity and specificity. In recent years, the role of multiparametric magnetic resonance imaging has steadily grown, and is now part of the standard clinical management in many institutions. In multiparametric magnetic resonance imaging, the morphological assessment of T2-weighted imaging is correlated with diffusion-weighted imaging, dynamic contrast-enhanced imaging perfusion and/or magnetic resonance spectroscopic imaging. Multiparametric magnetic resonance imaging is currently regarded as the most sensitive and specific imaging technique for the evaluation of prostate cancer, including detection, staging, localization and aggressiveness evaluation. This article presents an overview of multiparametric magnetic resonance imaging, and discusses the current role of multiparametric magnetic resonance imaging in the different fields of prostate cancer management. PMID:27184019

  15. Magnetic resonance imaging

    SciTech Connect

    Elster, A.D.

    1986-01-01

    The author succeeds in making the physical phenomena of MR imaging quite comprehensible. The chapters on imaging sequences and parameters and the effects of pathologic conditions on MR images are written in a way that helps the beginner. MR artifacts are discussed in a special chapter. The atlas, which makes up 60% of the book; includes a detailed imaging guide with protocols concentrating mainly on the head, neck and brain. MR imaging of the chest is discussed as well as abdomen, pelvis and hips, and the spine, breast, and knee. The book ends with a list of MR equipment manufacturers, specifications of nine major commercial MR imagers, and a glossary of MR terminology.

  16. HiSStology: High Spectral and Spatial Resolution Magnetic Resonance Imaging Detection of Vasculature Validated by Histology and Micro–Computed Tomography

    PubMed Central

    Haney, Chad R.; Pelizzari, Charles A.; Foxley, Sean; Zamora, Marta A.; Mustafi, Devkumar; Tretiakova, Maria; Li, Shihong; Fan, Xiaobing; Karczmar, Gregory S.

    2011-01-01

    High spectral and spatial resolution (HiSS) data, acquired with echo-planar spectroscopic imaging (EPSI), can be used to acquire water spectra from each small image voxel. These images are sensitive to changes in local susceptibility caused by superparamagnetic iron oxide particles (SPIO); therefore, we hypothesized that images derived from HiSS data are very sensitive to tumor neovasculature following injection of SPIO. Accurate image registration was used to validate HiSS detection of neovasculature with histology and micro–computed tomographic (microCT) angiography. Athymic nude mice and Copenhagen rats were inoculated with Dunning AT6.1 prostate tumor cells in the right hind limb. The tumor region was imaged pre– and post–intravenous injection of SPIO. Three-dimensional assemblies of the CD31-stained histologic slices of the mouse legs and the microCT images of the rat vascular casts were registered with EPSI. The average distance between HiSS-predicted regions of high vascular density on magnetic resonance imaging and CD31-stained regions on histology was 200 µm. Similarly, vessels identified by HiSS in the rat images coincided with vasculature in the registered microCT image. The data demonstrate a strong correlation between tumor vasculature identified using HiSS and two gold standards: histology and microCT angiography. PMID:21443840

  17. Recent technological and application developments in computed tomography and magnetic resonance imaging for improved pulmonary nodule detection and lung cancer staging

    PubMed Central

    Sieren, Jessica C.; Ohno, Yoshiharu; Koyama, Hisanobu; Sugimura, Kazuro; McLennan, Geoffrey

    2010-01-01

    This review compares the emerging technologies and approaches in the application of magnetic resonance (MR) and computed tomography (CT) imaging for the assessment of pulmonary nodules and staging of malignant findings. Included in this review is a brief definition of pulmonary nodules and an introduction to the challenges faced. We have highlighted the current status of both MR and CT for the early detection of lung nodules. Developments are detailed in this review for the management of pulmonary nodules using advanced imaging, including; dynamic imaging studies, dual energy CT, computer aided detection and diagnosis, and imaging assisted nodule biopsy approaches which have improved lung nodule detection and diagnosis rates. Recent advancements linking in-vivo imaging to corresponding histological pathology are also highlighted. In-vivo imaging plays a pivotal role in the clinical staging of pulmonary nodules through TNM assessment. While CT and PET/CT are currently the most commonly clinically employed modalities for pulmonary nodule staging, studies are presented which highlight the augmentative potential of MR. PMID:21105140

  18. Granular convection observed by magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Ehrichs, E. E.; Jaeger, H. M.; Karczmar, Greg S.; Knight, James B.; Kuperman, Vadim Yu.; Nagel, Sidney R.

    1995-03-01

    Vibrations in a granular material can spontaneously produce convection rolls reminiscent of those seen in fluids. Magnetic resonance imaging provides a sensitive and noninvasive probe for the detection of these convection currents, which have otherwise been difficult to observe. A magnetic resonance imaging study of convection in a column of poppy seeds yielded data about the detailed shape of the convection rolls and the depth dependence of the convection velocity. The velocity was found to decrease exponentially with depth; a simple model for this behavior is presented here.

  19. Granular convection observed by magnetic resonance imaging

    SciTech Connect

    Ehrichs, E.E.; Jaeger, H.M.; Knight, J.B.; Nagel, S.R.; Karczmar, G.S.; Kuperman, V.Yu.

    1995-03-17

    Vibrations in a granular material can spontaneously produce convection rolls reminiscent of those seen in fluids. Magnetic resonance imaging provides a sensitive and noninvasive probe for the detection of these convection currents, which have otherwise been difficult to observe. A magnetic resonance imaging study of convection in a column of poppy seeds yielded data about the detailed shape of the convection rolls and the depth dependence of the convection velocity. The velocity was found to decrease exponentially with depth; a simple model for this behavior is presented here. 31 refs., 4 figs.

  20. Curcumin-conjugated magnetic nanoparticles for detecting amyloid plaques in Alzheimer's disease mice using magnetic resonance imaging (MRI).

    PubMed

    Cheng, Kwok Kin; Chan, Pui Shan; Fan, Shujuan; Kwan, Siu Ming; Yeung, King Lun; Wáng, Yì-Xiáng J; Chow, Albert Hee Lum; Wu, Ed X; Baum, Larry

    2015-03-01

    Diagnosis of Alzheimer's disease (AD) can be performed with the assistance of amyloid imaging. The current method relies on positron emission tomography (PET), which is expensive and exposes people to radiation, undesirable features for a population screening method. Magnetic resonance imaging (MRI) is cheaper and is not radioactive. Our approach uses magnetic nanoparticles (MNPs) made of superparamagnetic iron oxide (SPIO) conjugated with curcumin, a natural compound that specifically binds to amyloid plaques. Coating of curcumin-conjugated MNPs with polyethylene glycol-polylactic acid block copolymer and polyvinylpyrrolidone by antisolvent precipitation in a multi-inlet vortex mixer produces stable and biocompatible curcumin magnetic nanoparticles (Cur-MNPs) with mean diameter <100 nm. These nanoparticles were visualized by transmission electron microscopy and atomic force microscopy, and their structure and chemistry were further characterized by X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, and Fourier transform infrared spectroscopy. Cur-MNPs exhibited no cytotoxicity in either Madin-Darby canine kidney (MDCK) or differentiated human neuroblastoma cells (SH-SY5Y). The Papp of Cur-MNPs was 1.03 × 10(-6) cm/s in an in vitro blood-brain barrier (BBB) model. Amyloid plaques could be visualized in ex vivo T2*-weighted magnetic resonance imaging (MRI) of Tg2576 mouse brains after injection of Cur-MNPs, and no plaques could be found in non-transgenic mice. Immunohistochemical examination of the mouse brains revealed that Cur-MNPs were co-localized with amyloid plaques. Thus, Cur-MNPs have the potential for non-invasive diagnosis of AD using MRI. PMID:25617135

  1. An automatic method for detection and classification of Ionospheric Alfvén Resonances using signal and image processing techniques

    NASA Astrophysics Data System (ADS)

    Beggan, Ciaran

    2014-05-01

    Induction coils permit us to measure the very rapid changes of the magnetic field. In June 2012, the British Geological Survey Geomagnetism team installed two high frequency (100 Hz) induction coil magnetometers at the Eskdalemuir Observatory (55.3° N, 3.2° W, L~3), in the Scottish Borders of the United Kingdom. The Eskdalemuir Observatory is one of the longest running geophysical sites in the UK (beginning operation in 1908) and is located in a rural valley with a quiet magnetic environment. The coils record magnetic field changes over an effective frequency range of about 0.1-40Hz, and encompass phenomena such as the Schumann resonances, magnetospheric pulsations and Ionospheric Alfvén Resonances (IAR). In this study we focus on the IAR, which are related to the vibration of magnetic field lines passing through the ionosphere, believed to be mainly excited by lower atmospheric electrical discharges. The IAR typically manifest as a series of spectral resonances structures (SRS) within the 1-6Hz frequency range, usually appearing a fine bands or fringes in spectrogram plots. The SRS tend to occur daily between 18.00-06.00UT at the Eskdalemuir site, disappearing during the daylight hours. They usually start as a single low frequency before bifurcating into 5-10 separate fringes, increasing in frequency until around midnight. The fringes also widen in frequency before fading around 06.00UT. Occasionally, the fringes decrease in frequency slightly around 03.00UT before fading. In order to quantify the daily, seasonal and annual changes of the SRS, we developed a new method to identify the fringes and to quantify their occurrence in frequency (f) and the change in frequency (Δf). The method uses short time-series of 100 seconds to produce an FFT spectral plot from which the non-stationary peaks are identified using the residuals from a best-fit six order spline. This is repeated for an entire day of data. The peaks from each time-slice are placed into a matrix

  2. Detection of enzyme activity in orthotopic murine breast cancer by fluorescence lifetime imaging using a fluorescence resonance energy transfer-based molecular probe

    NASA Astrophysics Data System (ADS)

    Solomon, Metasebya; Guo, Kevin; Sudlow, Gail P.; Berezin, Mikhail Y.; Edwards, W. Barry; Achilefu, Samuel; Akers, Walter J.

    2011-06-01

    Cancer-related enzyme activity can be detected noninvasively using activatable fluorescent molecular probes. In contrast to ``always-on'' fluorescent molecular probes, activatable probes are relatively nonfluorescent at the time of administration due to intramolecular fluorescence resonance energy transfer (FRET). Enzyme-mediated hydrolysis of peptide linkers results in reduced FRET and increase of fluorescence yield. Separation of signal from active and inactive probe can be difficult with conventional intensity-based fluorescence imaging. Fluorescence lifetime (FLT) measurement is an alternative method to detect changes in FRET. Thus, we investigate FLT imaging for in vivo detection of FRET-based molecular probe activation in an orthotopic breast cancer model. Indeed, the measured FLT of the enzyme-activatable molecular probe increases from 0.62 ns just after injection to 0.78 ns in tumor tissue after 4 h. A significant increase in FLT is not observed for an always-on targeted molecular probe with the same fluorescent reporter. These results show that FLT contrast is a powerful addition to preclinical imaging because it can report molecular activity in vivo due to changes in FRET. Fluorescence lifetime imaging exploits unique characteristics of fluorescent molecular probes that can be further translated into clinical applications, including noninvasive detection of cancer-related enzyme activity.

  3. Explosives detection with quadrupole resonance analysis

    NASA Astrophysics Data System (ADS)

    Rayner, Timothy J.; Thorson, Benjamin D.; Beevor, Simon; West, Rebecca; Krauss, Ronald A.

    1997-02-01

    The increase in international terrorist activity over the past decade has necessitated the exploration of new technologies for the detection of plastic explosives. Quadrupole resonance analysis (QRA) has proven effective as a technique for detecting the presence of plastic, sheet, and military explosive compounds in small quantities, and can also be used to identify narcotics such as heroin and cocaine base. QRA is similar to the widely used magnetic resonance (MR) and magnetic resonance imaging (MRI) techniques, but has the considerable advantage that the item being inspected does not need to be immersed in a steady, homogeneous magnetic field. The target compounds are conclusively identified by their unique quadrupole resonance frequencies. Quantum magnetics has develop and introduced a product line of explosives and narcotics detection devices based upon QRA technology. The work presented here concerns a multi-compound QRA detection system designed to screen checked baggage, cargo, and sacks of mail at airports and other high-security facilities. The design philosophy and performance are discussed and supported by test results from field trials conducted in the United States and the United Kingdom. This detection system represents the current state of QRA technology for field use in both commercial and government sectors.

  4. Increased microcirculation detected by dynamic contrast-enhanced magnetic resonance imaging is of prognostic significance in asymptomatic myeloma.

    PubMed

    Hillengass, Jens; Ritsch, Judith; Merz, Maximilian; Wagner, Barbara; Kunz, Christina; Hielscher, Thomas; Laue, Hendrik; Bäuerle, Tobias; Zechmann, Christian M; Ho, Anthony D; Schlemmer, Heinz-Peter; Goldschmidt, Hartmut; Moehler, Thomas M; Delorme, Stefan

    2016-07-01

    This prospective study aimed to investigate the prognostic significance of dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) as a non-invasive imaging technique delivering the quantitative parameters amplitude A (reflecting blood volume) and exchange rate constant kep (reflecting vascular permeability) in patients with asymptomatic monoclonal plasma cell diseases. We analysed DCE-MRI parameters in 33 healthy controls and 148 patients with monoclonal gammopathy of undetermined significance (MGUS) or smouldering multiple myeloma (SMM) according to the 2003 IMWG guidelines. All individuals underwent standardized DCE-MRI of the lumbar spine. Regions of interest were drawn manually on T1-weighted images encompassing the bone marrow of each of the 5 lumbar vertebrae sparing the vertebral vessel. Prognostic significance for median of amplitude A (univariate: P < 0·001, hazard ratio (HR) 2·42, multivariate P = 0·02, HR 2·7) and exchange rate constant kep (univariate P = 0·03, HR 1·92, multivariate P = 0·46, HR 1·5) for time to progression of 79 patients with SMM was found. Patients with amplitude A above the optimal cut-off point of 0·89 arbitrary units had a 2-year progression rate into symptomatic disease of 80%. In conclusion, DCE-MRI parameters are of prognostic significance for time to progression in patients with SMM but not in individuals with MGUS. PMID:26991959

  5. Labeling transplanted mice islet with polyvinylpyrrolidone coated superparamagnetic iron oxide nanoparticles for in vivo detection by magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Huang, Hai; Xie, Qiuping; Kang, Muxing; Zhang, Bo; Zhang, Hui; Chen, Jin; Zhai, Chuanxin; Yang, Deren; Jiang, Biao; Wu, Yulian

    2009-09-01

    Superparamagnetic iron oxide nanoparticles (SPIO) are emerging as a novel probe for noninvasive cell tracking with magnetic resonance imaging (MRI) and have potential wide usage in medical research. In this study, we have developed a method using high-temperature hydrolysis of chelate metal alkoxide complexes to synthesize polyvinylpyrrolidone coated iron oxide nanoparticles (PVP-SPIO), as a biocompatible magnetic agent that can efficiently label mice islet β-cells. The size, crystal structure and magnetic properties of the as-synthesized nanoparticles have been characterized. The newly synthesized PVP-SPIO with high stability, crystallinity and saturation magnetization can be efficiently internalized into β-cells, without affecting viability and function. The imaging of 100 PVP-SPIO-labeled mice islets in the syngeneic renal subcapsular model of transplantation under a clinical 3.0 T MR imager showed high spatial resolution in vivo. These results indicated the great potential application of the PVP-SPIO as an MRI contrast agent for monitoring transplanted islet grafts in the clinical management of diabetes in the near future.

  6. Magnetic resonance imaging (MRI) detection of the murine brain response to light: temporal differentiation and negative functional MRI changes.

    PubMed Central

    Huang, W; Plyka, I; Li, H; Eisenstein, E M; Volkow, N D; Springer, C S

    1996-01-01

    Using a 9.4 T MRI instrument, we have obtained images of the mouse brain response to photic stimulation during a period between deep anesthesia and the early stages of arousal. The large image enhancements we observe (often >30%) are consistent with literature results extrapolated to 9.4 T. However, there are also two unusual aspects to our findings. (i) The visual area of the brain responds only to changes in stimulus intensity, suggesting that we directly detect operations of the M visual system pathway. Such a channel has been observed in mice by invasive electrophysiology, and described in detail for primates. (ii) Along with the typical positive response in the area of the occipital portion of the brain containing the visual cortex, another area displays decreased signal intensity upon stimulation. Images Fig. 1 Fig. 4 PMID:8650215

  7. MRI (Magnetic Resonance Imaging)

    MedlinePlus

    ... some MRI exams, intravenous (IV) drugs, such as gadolinium-based contrast agents (GBCAs) are used to change the contrast of the MR image. Gadolinium-based contrast agents are rare earth metals that ...

  8. Usefulness of cervical magnetic resonance imaging for detecting type A acute aortic dissection with acute stroke symptoms.

    PubMed

    Matsumoto, Hiroaki; Yoshida, Yasuhisa; Hirata, Yutaka

    2016-09-01

    Type A acute aortic dissection (TAAAD) sometimes presents with acute stroke-like symptoms. When intravenous tissue plasminogen activator (IV-tPA) therapy is considered for acute ischemic stroke, TAAAD must be excluded. Painless TAAAD presenting with acute stroke may be easily missed. Two cases of painless TAAAD presenting with acute stroke in which IV-tPA therapy was considered are reported. In these cases, cervical magnetic resonance angiography (MRA) was useful for detecting TAAAD, and IV-tPA therapy was canceled. The mottled high signal ("snowstorm") in the common carotid artery on cervical MRA is specific for TAAAD. We have thus named this phenomenon the "snowstorm sign" and believe it can help diagnose TAAAD. PMID:27118510

  9. Magnetic Resonance Imaging Detects and Predicts Early Brain Injury after Subarachnoid Hemorrhage in a Canine Experimental Model

    PubMed Central

    Jadhav, Vikram; Sugawara, Takashi; Zhang, John; Jacobson, Paul

    2008-01-01

    Abstract The canine double hemorrhage model is an established model to study cerebral vasospasm, the late sequelae of subarachnoid hemorrhage (SAH). The present study uses magnetic resonance imaging (MRI) to examine the recently reported early brain injury after SAH. Double hemorrhage SAH modeling was obtained by injecting 0.5 mL/kg of autologous arterial blood into the cisterna magna of five adult mongrel dogs on day 0 and day 2, followed by imaging at day 2 and day 7 using a 4.7-Tesla (T) scanner. White matter (WM) showed a remarkable increase in T2 values at day 2 which resolved by day 7, whereas gray matter (GM) T2 values did not resolve. The apparent diffusion coefficient (ADC) values progressively increased in both WM and GM after SAH, suggestive of a transition from vasogenic to cytotoxic edema. Ventricular volume also increased dramatically. Prominent neuronal injury with Nissl's staining was seen in the cortical GM and in the periventricular tissue. Multimodal MRI reveals acute changes in the brain after SAH and can be used to non-invasively study early brain injury and normal pressure hydrocephalus post-SAH. MR can also predict tissue histopathology and may be useful for assessing pharmacological treatments designed to ameliorate SAH. PMID:18729770

  10. Biodegradable human serum albumin nanoparticles as contrast agents for the detection of hepatocellular carcinoma by magnetic resonance imaging.

    PubMed

    Watcharin, Waralee; Schmithals, Christian; Pleli, Thomas; Köberle, Verena; Korkusuz, Hüdayi; Huebner, Frank; Zeuzem, Stefan; Korf, Hans W; Vogl, Thomas J; Rittmeyer, Claudia; Terfort, Andreas; Piiper, Albrecht; Gelperina, Svetlana; Kreuter, Jörg

    2014-05-01

    Tumor visualization by magnetic resonance imaging (MRI) and nanoparticle-based contrast agents may improve the imaging of solid tumors such as hepatocellular carcinoma (HCC). In particular, human serum albumin (HSA) nanoparticles appear to be a suitable carrier due to their safety and feasibility of functionalization. In the present study HSA nanoparticles were conjugated with gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) using carbodiimide chemistry. The nanoparticles had a uniform spherical shape and a diameter of 235±19nm. For better optical visualization in vitro and in vivo, the HSA-Gd nanoparticles were additionally labeled with rhodamine 123. As shown by confocal microscopy and flow cytometry analysis, the fluorescent nanoparticles were readily taken up by Huh-7 hepatocellular carcinoma cells. After 24h incubation in blood serum, less than 5% of the Gd(III) was released from the particles, which suggests that this nanoparticulate system may be stable in vivo and, therefore, may serve as potentially safe T1 MRI contrast agent for MRI of hepatocellular carcinoma. PMID:24365328

  11. Pediatric Body Magnetic Resonance Imaging.

    PubMed

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

    2016-09-01

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

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

    PubMed

    Webb, Andrew

    2014-11-01

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

  13. Magnetic resonance imaging (MRI) detection of the murine brain response to light: Temporal differentiation and negative functional MRI changes

    SciTech Connect

    Huang, Wei; Palyka, I.; Li, HaiFang

    1996-06-11

    Using a 9.4 T MRI instrument, we have obtained images of the mouse brain response to photic stimulation during a period between deep anesthesia and the early stages of arousal. The large image enhancements we observe (often >30%) are consistent with literature results extrapolated to 9.4 T. However, there are also two unusual aspects to our findings. (i) The visual area of the brain responds only to changes in stimulus intensity, suggesting that we directly detect operations of the M visual system pathway. Such a channel has been observed in mice by invasive electrophysiology, and described in detail for primates. (ii) Along with the typical positive response in the area of the occipital portion of the brain containing the visual cortex; another area displays decreased signal intensity upon stimulation. 41 refs., 4 figs.

  14. Cranial magnetic resonance imaging

    SciTech Connect

    Elster, A.D.

    1987-01-01

    This illustrated work covers the diagnosis of central nervous system diseases by MRI. It focuses on strategies for detecting a wide range of intracranial disorders and includes protocols for cranial MRI. For each disease discussed, characteristic MR findings are described, and contrasted with CT and angiography where appropriate. Offers useful appendices on functional neuroanatomy and a glossary of terminology and abbreviations.

  15. Low field magnetic resonance imaging

    DOEpatents

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

    2010-07-13

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

  16. Low Rates of Additional Cancer Detection by Magnetic Resonance Imaging in Newly Diagnosed Breast Cancer Patients Who Undergo Preoperative Mammography and Ultrasonography

    PubMed Central

    Kim, Jisun; Han, Wonshik; Moon, Hyeong-Gon; Ahn, Soo Kyung; Shin, Hee-Chul; You, Jee-Man; Chang, Jung Min; Cho, Nariya; Moon, Woo Kyung; Park, In-Ae

    2014-01-01

    Purpose We evaluated the efficacy of breast magnetic resonance imaging (MRI) for detecting additional malignancies in breast cancer patients newly diagnosed by breast ultrasonography and mammography. Methods We retrospectively reviewed the records of 1,038 breast cancer patients who underwent preoperative mammography, bilateral breast ultrasonography, and subsequent breast MRI between August 2007 and December 2010 at single institution in Korea. MRI-detected additional lesions were defined as those lesions detected by breast MRI that were previously undetected by mammography and ultrasonography and which would otherwise have not been identified. Results Among the 1,038 cases, 228 additional lesions (22.0%) and 30 additional malignancies (2.9%) were detected by breast MRI. Of these 228 lesions, 109 were suspected to be malignant (Breast Imaging-Reporting and Data System category 4 or 5) on breast MRI and second-look ultrasonography and 30 were pathologically confirmed to be malignant (13.2%). Of these 30 lesions, 21 were ipsilateral to the main lesion and nine were contralateral. Fourteen lesions were in situ carcinomas and 16 were invasive carcinomas. The positive predictive value of breast MRI was 27.5% (30/109). No clinicopathological factors were significantly associated with additional malignant foci. Conclusion Breast MRI was useful in detecting additional malignancy in a small number of patients who underwent ultrasonography and mammography. PMID:25013439

  17. Magnetic resonance imaging of prostate cancer.

    PubMed

    Guneyli, Serkan; Erdem, Cemile Zuhal; Erdem, Lutfi Oktay

    2016-01-01

    Prostate cancer is one of the causes of cancer-related deaths. Multiparametric magnetic resonance imaging (MRI) provides the best soft tissue resolution and plays an important role in the management of prostate cancer patients. It is the recommended imaging modality for patients with prostate cancer, and it is clinically indicated for diagnosis, staging, tumor localization, detection of tumor aggressiveness, follow-up, and MRI-guided interventions. Multiparametric MRI includes T1- and high-resolution T2-weighted imaging, diffusion-weighted imaging, and dynamic contrast-enhanced MRI. We evaluated MR images of patients with prostate cancer who underwent multiparametric endorectal MRI on a 3.0-T scanner and presented demonstrative images. PMID:27317204

  18. Early detection of colonic dysplasia by magnetic resonance molecular imaging with a contrast agent raised against the colon cancer marker MUC5AC.

    PubMed

    Rossez, Yannick; Burtea, Carmen; Laurent, Sophie; Gosset, Pierre; Léonard, Renaud; Gonzalez, Walter; Ballet, Sébastien; Raynal, Isabelle; Rousseaux, Olivier; Dugué, Timothée; Vander Elst, Luce; Michalski, Jean-Claude; Muller, Robert N; Robbe-Masselot, Catherine

    2016-05-01

    Human gastric mucin MUC5AC is secreted in the colonic mucus of cancer patients and is a specific marker of precancerous lesions called aberrant crypt foci. Using MUC5AC as a specific marker can improve sensitivity in the detection of early colorectal cancer. Here we demonstrated that the accumulation of MUC5AC in xenograft and mouse stomach can be detected by magnetic resonance imaging (MRI). We used ultrasmall particles of iron oxide (USPIOs) conjugated with disulfide constrained heptapeptide that were identified using a screening phage display. To accomplish this, we employed positive selection of the phage display library on MUC5AC purified from fresh human colonic adenomas in combination with negative selection of the phage library on purified human MUC2, which is predominantly found in normal colorectal tissues. This conjugate was tested on human colorectal cancer cell lines that were either able or unable to secrete MUC5AC, both in vitro and in vivo. MUC5AC-USPIO contrast agent and USPIOs alone were not detected in cell lines unable to secrete MUC5AC. A combination of MRI and microscopy studies was performed to detect a specific accumulation of the contrast agent in vivo. Thus, the MUC5AC contrast agent enabled non-invasive detection of precancerous lesions and colorectal cancer, highlighting its potential use in diagnostics, in the early detection of colorectal cancer recurrences after treatment and in mechanistic studies implicating MUC5AC. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26762591

  19. 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

  20. Detection of vulnerable atherosclerosis plaques with a dual-modal single-photon-emission computed tomography/magnetic resonance imaging probe targeting apoptotic macrophages.

    PubMed

    Cheng, Dengfeng; Li, Xiao; Zhang, Chunfu; Tan, Hui; Wang, Cong; Pang, Lifang; Shi, Hongcheng

    2015-02-01

    Atherosclerosis (AS), especially the vulnerable AS plaque rupture-induced acute obstructive vascular disease, is a leading cause of death. Accordingly, there is a need for an effective method to draw accurate predictions about AS progression and plaque vulnerability. Herein we report on an approach to constructing a hybrid nanoparticle system using a single-photon-emission computed tomography (SPECT)/magnetic resonance imaging (MRI) multimodal probe, aiming for a comprehensive evaluation of AS progression by achieving high sensitivity along with high resolution. Ultrasmall superparamagnetic iron oxide (USPIO) was covered by aminated poly(ethylene glycol) (PEG) and carboxylated PEG simultaneously and then functionalized with diethylenetriaminepentacetate acid for (99m)Tc coordination and subsequently Annexin V for targeting apoptotic macrophages abundant in vulnerable plaques. The in vivo accumulations of imaging probe reflected by SPECT and MRI were consistent and accurate in highlighting lesions. Intense radioactive signals detected by SPECT facilitated focus recognization and quantification, while USPIO-based T2-weighted MRI improved the focal localization and volumetry of AS plaques. For subsequent ex vivo planar images, targeting effects were further confirmed by immunohistochemistry, including CD-68 and TUNEL staining; meanwhile, the degree of concentration was proven to be statistically correlated with the Oil Red O staining results. In conclusion, these results indicated that the Annexin V-modified hybrid nanoparticle system specifically targeted the vulnerable AS plaques containing apoptotic macrophages and could be of great value in the invasively accurate detection of vulnerable plaques. PMID:25569777

  1. Basics of magnetic resonance imaging

    SciTech Connect

    Oldendorf, W.; Oldendorf, W. Jr.

    1988-01-01

    Beginning with the behavior of a compass needle in a magnetic field, this text uses analogies from everyday experience to explain the phenomenon of nuclear magnetic resonance and how it is used for imaging. Using a minimum of scientific abbreviations and symbols, the basics of tissue visualization and characterization are presented. A description of the various types of magnets and scanners is followed by the practical advantages and limitations of MRI relative to x-ray CT scanning.

  2. In Vivo Magnetization Transfer and Diffusion-Weighted Magnetic Resonance Imaging Detects Thrombus Composition in a Mouse Model of Deep Vein Thrombosis

    PubMed Central

    Saha, Prakash; Modarai, Bijan; Smith, Alberto; Botnar, René M.

    2014-01-01

    Background Deep vein thrombosis remains a major health problem necessitating accurate diagnosis. Thrombolysis is associated with significant morbidity and is effective only for the treatment of unorganized thrombus. We tested the feasibility of in vivo magnetization transfer (MT) and diffusion-weighted magnetic resonance imaging to detect thrombus organization in a murine model of deep vein thrombosis. Methods and Results Deep vein thrombosis was induced in the inferior vena cava of male BALB/C mice. Magnetic resonance imaging was performed at days 1, 7, 14, 21, and 28 after thrombus induction using MT, diffusion-weighted, inversion-recovery, and T1-mapping protocols. Delayed enhancement and T1 mapping were repeated 2 hours after injection of a fibrin contrast agent. Finally, excised thrombi were used for histology. We found that MT and diffusion-weighted imaging can detect histological changes associated with thrombus aging. MT rate (MTR) maps and percentage of MT rate (%MTR) allowed visualization and quantification of the thrombus protein content, respectively. The %MTR increased with thrombus organization and was significantly higher at days 14, 21, and 28 after thrombus induction (days 1, 7, 14, 21, 28: %MTR=2483±451, 2079±1210, 7029±2490, 10 295±4356, 32 994±25 449; Panova<0.05). There was a significant positive correlation between the %MTR and the histological protein content of the thrombus (r=0.70; P<0.05). The apparent diffusion coefficient was lower in erythrocyte-rich and collagen-rich thrombus (0.72±0.10 and 0.69±0.05 [×10−3 mm2/s]). Thrombus at days 7 and 14 had the highest apparent diffusion coefficient values (0.95±0.09 and 1.10±0.18 [×10−3 mm2/s]). Conclusions MT and diffusion-weighted magnetic resonance imaging sequences are promising for the staging of thrombus composition and could be useful in guiding medical intervention. PMID:23564561

  3. Magnetic Resonance Imaging of Acute Stroke.

    PubMed

    Nael, Kambiz; Kubal, Wayne

    2016-05-01

    Neuroimaging plays a critical role in the management of patients with acute stroke syndrome, with diagnostic, therapeutic, and prognostic implications. A multiparametric magnetic resonance (MR) imaging protocol in the emergency setting can address both primary goals of neuroimaging (ie, detection of infarction and exclusion of hemorrhage) and secondary goals of neuroimaging (ie, identifying the site of arterial occlusion, tissue characterization for defining infarct core and penumbra, and determining stroke cause/mechanism). MR imaging provides accurate diagnosis of acute ischemic stroke (AIS) and can differentiate AIS from other potential differential diagnoses. PMID:27150320

  4. Magnetic resonance imaging of acquired cardiac disease.

    PubMed Central

    Carrol, C L; Higgins, C B; Caputo, G R

    1996-01-01

    Over the last 15 years, advances in magnetic resonance imaging techniques have increased the accuracy and applicability of cardiovascular magnetic resonance imaging. These advances have improved the utility of magnetic resonance imaging in evaluating cardiac morphology, blood flow, and myocardial contractility, all significant diagnostic features in the evaluation of the patient with acquired heart disease. Utilization of cardiovascular magnetic resonance imaging has been limited, primarily due to clinical reliance upon nuclear scintigraphy and echocardiography. Recent developments in fast and ultrafast imaging should continue to enhance the significance of magnetic resonance imaging in this field. Widespread use of magnetic resonance imaging in the evaluation of the cardiovascular system will ultimately depend upon its maturation into a comprehensive, noninvasive imaging technique for the varying manifestations of acquired heart disease, including cardiomyopathy, ischemic heart disease, and acquired valvular disease. Images PMID:8792545

  5. 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 0.54х106 to 59.77х106 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: ΔQ=[-11,-2]%, Δf=[-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.

  6. Diagnosis of hematogenous pyogenic vertebral osteomyelitis by magnetic resonance imaging

    SciTech Connect

    Meyers, S.P.; Wiener, S.N. )

    1991-04-01

    The clinical information and imaging data from 27 patients with hematogenous pyogenic vertebral osteomyelitis were reviewed. All patients had roentgenographic and magnetic resonance imaging examinations. Seventeen patients had computed tomograms; 17 had technetium Tc 99m medronate bone scans; and seven had gallium citrate Ga 67 scans. Magnetic resonance imaging, when used as a part of the initial radiologic evaluation, detected abnormalities consistent with osteomyelitis in all 27 patients. Magnetic resonance imaging also demonstrated paravertebral and/or epidural extension of infection in 14 patients, including seven patients who had neurologic signs of lower-extremity weakness. Roentgenograms, computed tomograms, technetium bone scans, and gallium scans had findings suggestive of the diagnosis in 48%, 65%, 71%, and 86% of the patients, respectively. We recommend magnetic resonance imaging as an important and perhaps critical imaging modality for detection of pyogenic vertebral osteomyelitis.

  7. Magnetic resonance imaging with an optical atomicmagnetometer

    SciTech Connect

    Xu, Shoujun; Yashchuk, Valeriy V.; Donaldson, Marcus H.; Rochester, Simon M.; Budker, Dmitry; Pines, Alexander

    2006-05-09

    Magnetic resonance imaging (MRI) is a noninvasive andversatile methodology that has been applied in many disciplines1,2. Thedetection sensitivity of conventional Faraday detection of MRI depends onthe strength of the static magnetic field and the sample "fillingfactor." Under circumstances where only low magnetic fields can be used,and for samples with low spin density or filling factor, the conventionaldetection sensitivity is compromised. Alternative detection methods withhigh sensitivity in low magnetic fields are thus required. Here we showthe first use of a laser-based atomic magnetometer for MRI detection inlow fields. Our technique also employs remote detection which physicallyseparates the encoding and detection steps3-5, to improve the fillingfactor of the sample. Potentially inexpensive and using a compactapparatus, our technique provides a novel alternative for MRI detectionwith substantially enhanced sensitivity and time resolution whileavoiding the need for cryogenics.

  8. Magnetic resonance acoustic radiation force imaging

    PubMed Central

    McDannold, Nathan; Maier, Stephan E.

    2008-01-01

    Acoustic radiation force impulse imaging is an elastography method developed for ultrasound imaging that maps displacements produced by focused ultrasound pulses systematically applied to different locations. The resulting images are “stiffness weighted” and yield information about local mechanical tissue properties. Here, the feasibility of magnetic resonance acoustic radiation force imaging (MR-ARFI) was tested. Quasistatic MR elastography was used to measure focal displacements using a one-dimensional MRI pulse sequence. A 1.63 or 1.5 MHz transducer supplied ultrasound pulses which were triggered by the magnetic resonance imaging hardware to occur before a displacement-encoding gradient. Displacements in and around the focus were mapped in a tissue-mimicking phantom and in an ex vivo bovine kidney. They were readily observed and increased linearly with acoustic power in the phantom (R2=0.99). At higher acoustic power levels, the displacement substantially increased and was associated with irreversible changes in the phantom. At these levels, transverse displacement components could also be detected. Displacements in the kidney were also observed and increased after thermal ablation. While the measurements need validation, the authors have demonstrated the feasibility of detecting small displacements induced by low-power ultrasound pulses using an efficient magnetic resonance imaging pulse sequence that is compatible with tracking of a dynamically steered ultrasound focal spot, and that the displacement increases with acoustic power. MR-ARFI has potential for elastography or to guide ultrasound therapies that use low-power pulsed ultrasound exposures, such as drug delivery. PMID:18777934

  9. Bcl-2-functionalized ultrasmall superparamagnetic iron oxide nanoparticles coated with amphiphilic polymer enhance the labeling efficiency of islets for detection by magnetic resonance imaging

    PubMed Central

    Yang, Bin; Cai, Haolei; Qin, Wenjie; Zhang, Bo; Zhai, Chuanxin; Jiang, Biao; Wu, Yulian

    2013-01-01

    Based on their versatile, biocompatible properties, superparamagnetic iron oxide (SPIO) or ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles are utilized for detecting and tracing cells or tumors in vivo. Here, we developed an innoxious and concise synthesis approach for a novel B-cell lymphoma (Bcl)-2 monoclonal antibody-functionalized USPIO nanoparticle coated with an amphiphilic polymer (carboxylated polyethylene glycol monooleyl ether [OE-PEG-COOH]). These nanoparticles can be effectively internalized by beta cells and label primary islet cells, at relatively low iron concentration. The biocompatibility and cytotoxicity of these products were investigated by comparison with the commercial USPIO product, FeraSpin™ S. We also assessed the safe dosage range of the product. Although some cases showed a hypointensity change at the site of transplant, a strong magnetic resonance imaging (MRI) was detectable by a clinical MRI scanner, at field strength of 3.0 Tesla, in vivo, and the iron deposition/attached in islets was confirmed by Prussian blue and immunohistochemistry staining. It is noteworthy that based on our synthesis approach, in future, we could exchange the Bcl-2 with other probes that would be more specific for the targeted cells and that would have better labeling specificity in vivo. The combined results point to the promising potential of the novel Bcl-2-functionalized PEG-USPIO as a molecular imaging agent for in vivo monitoring of islet cells or other cells. PMID:24204136

  10. Magnetic resonance imaging of pancreatitis: An update

    PubMed Central

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

    2014-01-01

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

  11. Molecular magnetic resonance imaging in cancer.

    PubMed

    Haris, Mohammad; Yadav, Santosh K; Rizwan, Arshi; Singh, Anup; Wang, Ena; Hariharan, Hari; Reddy, Ravinder; Marincola, Francesco M

    2015-01-01

    The ability to identify key biomolecules and molecular changes associated with cancer malignancy and the capacity to monitor the therapeutic outcome against these targets is critically important for cancer treatment. Recent developments in molecular imaging based on magnetic resonance (MR) techniques have provided researchers and clinicians with new tools to improve most facets of cancer care. Molecular imaging is broadly described as imaging techniques used to detect molecular signature at the cellular and gene expression levels. This article reviews both established and emerging molecular MR techniques in oncology and discusses the potential of these techniques in improving the clinical cancer care. It also discusses how molecular MR, in conjunction with other structural and functional MR imaging techniques, paves the way for developing tailored treatment strategies to enhance cancer care. PMID:26394751

  12. Magnetic resonance imaging of pancreatitis: an update.

    PubMed

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

    2014-10-28

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

  13. Far-field super-resolution imaging of resonant multiples

    PubMed Central

    Guo, Bowen; Huang, Yunsong; Røstad, Anders; Schuster, Gerard

    2016-01-01

    We demonstrate for the first time that seismic resonant multiples, usually considered as noise, can be used for super-resolution imaging in the far-field region of sources and receivers. Tests with both synthetic data and field data show that resonant multiples can image reflector boundaries with resolutions more than twice the classical resolution limit. Resolution increases with the order of the resonant multiples. This procedure has important applications in earthquake and exploration seismology, radar, sonar, LIDAR (light detection and ranging), and ultrasound imaging, where the multiples can be used to make high-resolution images. PMID:27386521

  14. Far-field super-resolution imaging of resonant multiples.

    PubMed

    Guo, Bowen; Huang, Yunsong; Røstad, Anders; Schuster, Gerard

    2016-05-01

    We demonstrate for the first time that seismic resonant multiples, usually considered as noise, can be used for super-resolution imaging in the far-field region of sources and receivers. Tests with both synthetic data and field data show that resonant multiples can image reflector boundaries with resolutions more than twice the classical resolution limit. Resolution increases with the order of the resonant multiples. This procedure has important applications in earthquake and exploration seismology, radar, sonar, LIDAR (light detection and ranging), and ultrasound imaging, where the multiples can be used to make high-resolution images. PMID:27386521

  15. Advances in mechanical detection of magnetic resonance

    PubMed Central

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

    2008-01-01

    The invention and initial demonstration of magnetic resonance force microscopy (MRFM) in the early 1990s launched a renaissance of mechanical approaches to detecting magnetic resonance. This article reviews progress made in MRFM in the last decade, including the demonstration of scanned probe detection of magnetic resonance (electron spin resonance, ferromagnetic resonance, and nuclear magnetic resonance) and the mechanical detection of electron spin resonance from a single spin. Force and force-gradient approaches to mechanical detection are reviewed and recent related work using attonewton sensitivity cantilevers to probe minute fluctuating electric fields near surfaces is discussed. Given recent progress, pushing MRFM to single proton sensitivity remains an exciting possibility. We will survey some practical and fundamental issues that must be resolved to meet this challenge. PMID:18266413

  16. Detection of prostate cancer by integration of line-scan diffusion, T2-mapping and T2-weighted magnetic resonance imaging; a multichannel statistical classifier.

    PubMed

    Chan, Ian; Wells, William; Mulkern, Robert V; Haker, Steven; Zhang, Jianqing; Zou, Kelly H; Maier, Stephan E; Tempany, Clare M C

    2003-09-01

    A multichannel statistical classifier for detecting prostate cancer was developed and validated by combining information from three different magnetic resonance (MR) methodologies: T2-weighted, T2-mapping, and line scan diffusion imaging (LSDI). From these MR sequences, four different sets of image intensities were obtained: T2-weighted (T2W) from T2-weighted imaging, Apparent Diffusion Coefficient (ADC) from LSDI, and proton density (PD) and T2 (T2 Map) from T2-mapping imaging. Manually segmented tumor labels from a radiologist, which were validated by biopsy results, served as tumor "ground truth." Textural features were extracted from the images using co-occurrence matrix (CM) and discrete cosine transform (DCT). Anatomical location of voxels was described by a cylindrical coordinate system. A statistical jack-knife approach was used to evaluate our classifiers. Single-channel maximum likelihood (ML) classifiers were based on 1 of the 4 basic image intensities. Our multichannel classifiers: support vector machine (SVM) and Fisher linear discriminant (FLD), utilized five different sets of derived features. Each classifier generated a summary statistical map that indicated tumor likelihood in the peripheral zone (PZ) of the prostate gland. To assess classifier accuracy, the average areas under the receiver operator characteristic (ROC) curves over all subjects were compared. Our best FLD classifier achieved an average ROC area of 0.839(+/-0.064), and our best SVM classifier achieved an average ROC area of 0.761(+/-0.043). The T2W ML classifier, our best single-channel classifier, only achieved an average ROC area of 0.599(+/-0.146). Compared to the best single-channel ML classifier, our best multichannel FLD and SVM classifiers have statistically superior ROC performance (P=0.0003 and 0.0017, respectively) from pairwise two-sided t-test. By integrating the information from multiple images and capturing the textural and anatomical features in tumor areas, summary

  17. 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

  18. Multifunctional Magnetic Gd(3+) -Based Coordination Polymer Nanoparticles: Combination of Magnetic Resonance and Multispectral Optoacoustic Detections for Tumor-Targeted Imaging in vivo.

    PubMed

    An, Qiao; Liu, Jing; Yu, Meng; Wan, Jiaxun; Li, Dian; Wang, Changchun; Chen, Chunying; Guo, Jia

    2015-11-11

    To overcome traditional barriers in optical imaging and microscopy, optoacoustic-imaging has been changed to combine the accuracy of spectroscopy with the depth resolution of ultrasound, achieving a novel modality with powerful in vivo imaging. However, magnetic resonance imaging provides better spatial and anatomical resolution. Thus, a single hybrid nanoprobe that allows for simultaneous multimodal imaging is significant not only for cutting edge research in imaging science, but also for accurate clinical diagnosis. A core-shell-structured coordination polymer composite microsphere has been designed for in vivo multimodality imaging. It consists of a Fe3 O4 nanocluster core, a carbon sandwiched layer, and a carbocyanine-Gd(III) (Cy-Gd(III) ) coordination polymer outer shell (Fe3 O4 @C@Cy-Gd(III) ). Folic acid-conjugated poly(ethylene glycol) chains are embedded within the coordination polymer shell to achieve extended circulation and targeted delivery of probe particles in vivo. Control of Fe3 O4 core grain sizes results in optimal r2 relaxivity (224.5 × 10(-3) m(-1) s(-1) ) for T2 -weighted magnetic resonance imaging. Cy-Gd(III) coordination polymers are also regulated to obtain a maximum 25.1% of Cy ligands and 5.2% of Gd(III) ions for near-infrared fluorescence and T1 -weighted magnetic resonance imaging, respectively. The results demonstrate their impressive abilities for targeted, multimodal, and reliable imaging. PMID:26366746

  19. Comparison of three dimensional magnetic resonance imaging in conjunction with a blood pool contrast agent and nuclear scintigraphy for the detection of experimentally induced gastrointestinal bleeding

    PubMed Central

    Hilfiker, P; Weishaupt, D; Kacl, G; Hetzer, F; Griff, M; Ruehm, S; Debatin, J

    1999-01-01

    BACKGROUND AND AIMS—To compare the performance of 3D magnetic resonance imaging (MRI) in conjunction with an intravascular contrast agent with that of scintigraphy, with respect to detection and localisation of gastrointestinal haemorrhage in vivo in pigs.
METHODS—Intraluminal bleeding sites were surgically created in the small bowel and colon of six pigs. The animals underwent scintigraphy with 99mTc labelled red blood cells and 3D MRI following administration of an intravascular contrast agent (NC100150) at five minute intervals over 30 minutes. For analysis, the intestinal tract was divided into six segments. Based on the two evaluated methods, each segment was characterised on a five point scale regarding the presence of a bleed. At autopsy, the surgically manipulated bowel segments were inspected for the presence of haemorrhage.
RESULTS—Bleeding was confirmed at autopsy in 18/36 segments. Contrast extravasation with subsequent movement through the bowel could be documented on MRI data sets. All segments were correctly characterised, resulting in 100% sensitivity and specificity for MRI. Based on scintigraphy, interpretation of seven segments (19%) was false (sensitivity/specificity of 78%/72%). Differences in diagnostic performance were evident in the receiver operator characteristic (ROC) analysis, with an area under the MRI curve of 0.99 and under the scintigraphy curve of 0.85.
CONCLUSION—In conjunction with an intravascular contrast agent, 3D MRI permits accurate detection and localisation of gastrointestinal bleeding. The extent and evolution of intestinal bleeding can be determined with repeated data acquisition.


Keywords: gastrointestinal tract; haemorrhage; scintigraphy; magnetic resonance; contrast agent PMID:10486369

  20. Early Detection of Ventilation-Induced Brain Injury Using Magnetic Resonance Spectroscopy and Diffusion Tensor Imaging: An In Vivo Study in Preterm Lambs

    PubMed Central

    Skiöld, Béatrice; Wu, Qizhu; Hooper, Stuart B.; Davis, Peter G.; McIntyre, Richard; Tolcos, Mary; Pearson, James; Vreys, Ruth; Egan, Gary F.; Barton, Samantha K.; Cheong, Jeanie L. Y.; Polglase, Graeme R.

    2014-01-01

    Background and Aim High tidal volume (VT) ventilation during resuscitation of preterm lambs results in brain injury evident histologically within hours after birth. We aimed to investigate whether magnetic resonance spectroscopy (MRS) and/or diffusion tensor imaging (DTI) can be used for early in vivo detection of ventilation-induced brain injury in preterm lambs. Methods Newborn lambs (0.85 gestation) were stabilized with a “protective ventilation” strategy (PROT, n = 7: prophylactic Curosurf, sustained inflation, VT 7 mL/kg, positive end expiratory pressure (PEEP) 5 cmH2O) or an initial 15 minutes of “injurious ventilation” (INJ, n = 10: VT 12 mL/kg, no PEEP, late Curosurf) followed by PROT ventilation for the remainder of the experiment. At 1 hour, lambs underwent structural magnetic resonance imaging (Siemens, 3 Tesla). For measures of mean/axial/radial diffusivity (MD, AD, RD) and fractional anisotropy (FA), 30 direction DTI was performed. Regions of interests encompassed the thalamus, internal capsule, periventricular white matter and the cerebellar vermis. MRS was performed using a localized single-voxel (15×15×20 mm3, echo time 270 ms) encompassing suptratentorial deep nuclear grey matter and central white matter. Peak-area ratios for lactate (Lac) relative to N-acetylaspartate (NAA), choline (Cho) and creatine (Cr) were calculated. Groups were compared using 2-way RM-ANOVA, Mann-Whitney U-test and Spearman's correlations. Results No cerebral injury was seen on structural MR images. Lambs in the INJ group had higher mean FA and lower mean RD in the thalamus compared to PROT lambs, but not in the other regions of interest. Peak-area lactate ratios >1.0 was only seen in INJ lambs. A trend of higher mean peak-area ratios for Lac/Cr and Lac/Cho was seen, which correlated with lower pH in both groups. Conclusion Acute changes in brain diffusion measures and metabolite peak-area ratios were observed after injurious ventilation. Early MRS/DTI is

  1. Role of short-term follow-up magnetic resonance imaging in the detection of post-operative residual breast cancer

    PubMed Central

    Zhang, Yili; Du, Hongwen

    2016-01-01

    The aim of the present study was to evaluate the role of short-term follow-up magnetic resonance imaging (MRI) in the detection of postoperative residual breast cancer. A retrospective analysis was performed on 10 patients who were diagnosed with non-malignant breast lesions by preoperative clinical, ultrasound and mammography examinations and intraoperative frozen-section pathology. These patients were finally confirmed as having malignant breast lesions by paraffin-embedded tissue histology and corresponding received second surgeries. Routine MRI, enhancement MRI and echo-planar imaging-diffusion-weighted imaging were performed on the 10 patients within 1 month after the first surgery. All the cases showed a local distortion of mammary architecture revealed by routine MRI and enhancement MRI images. The enhancement characteristics of the 10 cases were as follows: 3 cases featured stippled enhancement, 2 had small nodular enhancement, 1 showed dendritic enhancement, 1 had a ring-shaped enhancement of the cystic wall and 3 had no abnormal enhancement. The lesions of 7 cases had a type-I enhancement curve (progressive enhancement pattern) and 3 cases had a type-II curve (plateau pattern). The lesions of 4 cases had a decreased apparent diffusion coefficient. In total, 4 cases of tumor residue were diagnosed by MRI and the second pathological examination, while in 1 case the tumor residue was misdiagnosed by MRI but confirmed by the second pathological examination. In conclusion, the present study suggested that short-term follow-up MRI may be of value in the diagnosis of postoperative residual breast tumors and may be helpful for surgeons to develop an accurate surgical plan. PMID:27446586

  2. Magnetic resonance imaging of experimental cerebral oedema.

    PubMed Central

    Barnes, D; McDonald, W I; Tofts, P S; Johnson, G; Landon, D N

    1986-01-01

    Triethyl tin(TET)-induced cerebral oedema has been studied in cats by magnetic resonance imaging (MRI), and the findings correlated with the histology and fine structure of the cerebrum following perfusion-fixation. MRI is a sensitive technique for detecting cerebral oedema, and the distribution and severity of the changes correlate closely with the morphological abnormalities. The relaxation times, T1 and T2 increase progressively as the oedema develops, and the proportional increase in T2 is approximately twice that in T1. Analysis of the magnetisation decay curves reveals slowly-relaxing and rapidly-relaxing components which probably correspond to oedema fluid and intracellular water respectively. The image appearances taken in conjunction with relaxation data provide a basis for determining the nature of the oedema in vivo. Images PMID:3806109

  3. Artifacts in Magnetic Resonance Imaging

    PubMed Central

    Krupa, Katarzyna; Bekiesińska-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

  4. A new magnetic resonance imaging contrast agent loaded into poly(lacide-co-glycolide) nanoparticles for long-term detection of tumors.

    PubMed

    Rigaux, G; Roullin, V G; Cadiou, C; Portefaix, C; Van Gulick, L; Bœuf, G; Andry, M C; Hoeffel, C; Vander Elst, L; Laurent, S; Muller, R; Molinari, M; Chuburu, F

    2014-11-01

    The incorporation of a lipophilic Gd chelate (GdDO3A-C12) in biocompatible PLGA poly(D, L-lactide-co-glycolide) nanoparticles was explored as an approach to increase the relaxivity of contrast agents for magnetic resonance imaging. By nanoprecipitation, it was possible to obtain PEGylated gadolinium nanoparticles (mean diameter of 155 nm) with high Gd loading (1.1 × 10(4) Gd centers per nanoparticle). The corresponding GdDO3AC12 ⊂ NPs nanoparticles exhibited an enhanced relaxivity (up to sixfold greater than DOTAREM® at 40 MHz) because the nanoparticle framework constrained the lipophilic Gd chelate motion and favorably impacted the Gd chelate rotational correlation time. T1-weighted imaging at 3 T on phantoms showed enhanced contrast for the GdDO3AC12 ⊂ NPs. Importantly, Gd chelate leakage was almost nonexistent, which suggested that these GdDO3AC12 ⊂ NPs could be useful for long-term MRI detection. PMID:25325295

  5. Humanitarian mine detection by acoustic resonance

    SciTech Connect

    Kercel, S.W.

    1998-03-01

    The JASON Committee at MITRE Corp. was tasked by DARPA to inquire into suitable technologies for humanitarian mine detection. Acoustic resonance was one of the very few technologies that the JASONs determined might be promising for the task, but was as yet unexplored at the time that they conducted their inquiry. The objective of this Seed Money investigation into acoustic resonance was to determine if it would be feasible to use acoustic resonance to provide an improvement to present methods for humanitarian mine detection. As detailed in this report, acoustic resonance methods do not appear to be feasible for this task. Although acoustic resonant responses are relatively easy to detect when they exist, they are very difficult to excite by the non-contact means that must be used for buried objects. Despite many different attempts, this research did not discover any practical means of using sound to excite resonant responses in objects known to have strong resonances. The shaker table experiments did see an effect that might be attributable to the resonance of the object under test, but the effect was weak, and exploited the a priori knowledge of the resonant frequency of the object under test to distinguish it from the background. If experiments that used objects known to have strong acoustic resonances produced such marginal results, this does not seem to be a practical method to detect objects with weak resonances or non-existent resonances. The results of this work contribute to the ORNL countermine initiative. ORNL is exploring several unconventional mine detection technologies, and is proposed to explore others. Since this research has discovered some major pitfalls in non-metallic mine detection, this experience will add realism to other strategies proposed for mine detection technologies. The experiment provided hands-on experience with inert plastic mines under field conditions, and gives ORNL additional insight into the problems of developing practical

  6. Foundations of Advanced Magnetic Resonance Imaging

    PubMed Central

    Bammer, Roland; Skare, Stefan; Newbould, Rexford; Liu, Chunlei; Thijs, Vincent; Ropele, Stefan; Clayton, David B.; Krueger, Gunnar; Moseley, Michael E.; Glover, Gary H.

    2005-01-01

    Summary: During the past decade, major breakthroughs in magnetic resonance imaging (MRI) quality were made by means of quantum leaps in scanner hardware and pulse sequences. Some advanced MRI techniques have truly revolutionized the detection of disease states and MRI can now—within a few minutes—acquire important quantitative information noninvasively from an individual in any plane or volume at comparatively high resolution. This article provides an overview of the most common advanced MRI methods including diffusion MRI, perfusion MRI, functional MRI, and the strengths and weaknesses of MRI at high magnetic field strengths. PMID:15897944

  7. 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.

  8. Multimodal Wavelet Embedding Representation for data Combination (MaWERiC): Integrating Magnetic Resonance Imaging and Spectroscopy for Prostate Cancer Detection

    PubMed Central

    Tiwari, Pallavi; Kurhanewicz, John; Viswanath, Satish; Sridhar, Akshay; Madabhushi, Anant

    2011-01-01

    Rationale and Objectives To develop a computerized data integration framework (MaWERiC) for quantitatively combining structural and metabolic information from different Magnetic Resonance (MR) imaging modalities. Materials and Methods In this paper, we present a novel computerized support system that we call Multimodal Wavelet Embedding Representation for data Combination (MaWERiC) which (1) employs wavelet theory and dimensionality reduction for providing a common, uniform representation of the different imaging (T2-w) and non-imaging (spectroscopy) MRI channels, and (2) leverages a random forest classifier for automated prostate cancer detection on a per voxel basis from combined 1.5 Tesla in vivo MRI and MRS. Results A total of 36 1.5 T endorectal in vivo T2-w MRI, MRS patient studies were evaluated on a per-voxel via MaWERiC, using a three-fold cross validation scheme across 25 iterations. Ground truth for evaluation of the results was obtained via ex-vivo whole-mount histology sections which served as the gold standard for expert radiologist annotations of prostate cancer on a per-voxel basis. The results suggest that MaWERiC based MRS-T2-w meta-classifier (mean AUC, μ = 0.89 ± 0.02) significantly outperformed (i) a T2-w MRI (employing wavelet texture features) classifier (μ = 0.55± 0.02), (ii) a MRS (employing metabolite ratios) classifier (μ= 0.77 ± 0.03), (iii) a decision-fusion classifier, obtained by combining individual T2-w MRI and MRS classifier outputs (μ = 0.85 ± 0.03) and (iv) a data combination scheme involving combination of metabolic MRS and MR signal intensity features (μ = 0.66± 0.02). Conclusion A novel data integration framework, MaWERiC, for combining imaging and non-imaging MRI channels was presented. Application to prostate cancer detection via combination of T2-w MRI and MRS data demonstrated significantly higher AUC and accuracy values compared to the individual T2-w MRI, MRS modalities and other data integration strategies

  9. Zeptomole Detection of C-Reactive Protein in Serum by a Nanoparticle Amplified Surface Plasmon Resonance Imaging Aptasensor

    NASA Astrophysics Data System (ADS)

    Vance, Stephen A.; Sandros, Marinella G.

    2014-05-01

    Diagnostic biomarkers (i.e. proteins) are often in low abundance in bodily fluids presenting many challenges for their detection. In order to extend the application of SPRi systems in detecting biomarkers at ultralow levels, we combine the advantage of aptamer technology with nanomaterials and microwave-assisted surface functionalization. By implementing a sandwich assay through the introduction of aptamer-modified quantum dots (QDs), it was possible to measure 7 zeptomole (at 5 fg/mL) of C-reactive protein (CRP) selectively in spiked human serum. It is expected that the proposed platform will provide new direction in designing ultrasensitive SPRi biosensors with multiplexing capabilities.

  10. Functional Magnetic Resonance Imaging Methods

    PubMed Central

    Chen, Jingyuan E.; Glover, Gary H.

    2015-01-01

    Since its inception in 1992, Functional Magnetic Resonance Imaging (fMRI) has become an indispensible tool for studying cognition in both the healthy and dysfunctional brain. FMRI monitors changes in the oxygenation of brain tissue resulting from altered metabolism consequent to a task-based evoked neural response or from spontaneous fluctuations in neural activity in the absence of conscious mentation (the “resting state”). Task-based studies have revealed neural correlates of a large number of important cognitive processes, while fMRI studies performed in the resting state have demonstrated brain-wide networks that result from brain regions with synchronized, apparently spontaneous activity. In this article, we review the methods used to acquire and analyze fMRI signals. PMID:26248581

  11. Dextran hydrogel coated surface plasmon resonance imaging (SPRi) sensor for sensitive and label-free detection of small molecule drugs

    NASA Astrophysics Data System (ADS)

    Li, Shaopeng; Yang, Mo; Zhou, Wenfei; Johnston, Trevor G.; Wang, Rui; Zhu, Jinsong

    2015-11-01

    The label-free and sensitive detection of small molecule drugs on SPRi is still a challenging task, mainly due to the limited surface immobilization capacity of the sensor. In this research, a dextran hydrogel-coated gold sensor chip for SPRi was successfully fabricated via photo-cross-linking for enhanced surface immobilization capacity. The density of the dextran hydrogel was optimized for protein immobilization and sensitive small molecule detection. The protein immobilization capacity of the hydrogel was 10 times greater than a bare gold surface, and 20 times greater than an 11-mercaptoundecanoic acid (MUA) surface. Such a drastic improvement in immobilization capacity allowed the SPRi sensor to detect adequate response signals when probing small molecule binding events. The binding signal of 4 nM liquid-phase biotin to streptavidin immobilized on the dextran surface reached 435 RU, while no response was observed on bare gold or MUA surfaces. The dextran hydrogel-coated SPRi sensor was also applied in a kinetic study of the binding between an immunosuppressive drug (FK506) and its target protein (FKBP12) in a high-throughput microarray format. The measured binding affinity was shown to be consistent with reported literature values, and a detection limit of 0.5 nM was achieved.

  12. 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.

  13. Determinants of discrepancies in detection and comparison of the prognostic significance of left ventricular hypertrophy by electrocardiogram and cardiac magnetic resonance imaging.

    PubMed

    Bacharova, Ljuba; Chen, Haiying; Estes, E Harvey; Mateasik, Anton; Bluemke, David A; Lima, Joao A C; Burke, Gregory L; Soliman, Elsayed Z

    2015-02-15

    Despite the low sensitivity of the electrocardiogram (ECG) in detecting left ventricular hypertrophy (LVH), ECG-LVH is known to be a strong predictor of cardiovascular risk. Understanding reasons for the discrepancies in detection of LVH by ECG versus imaging could help improve the diagnostic ability of ECG. We examined factors associated with false-positive and false-negative ECG-LVH, using cardiac magnetic resonance imaging (MRI) as the gold standard. We also compared the prognostic significance of ECG-LVH and MRI-LVH as predictors of cardiovascular events. This analysis included 4,748 participants (mean age 61.9 years, 53.5% females, 61.7% nonwhites). Logistic regression with stepwise selection was used to identify factors associated with false-positive (n = 208) and false-negative (n = 387), compared with true-positive (n = 208) and true-negative (n = 4,041) ECG-LVH, respectively. A false-negative ECG-LVH status was associated with increased odds of Hispanic race/ethnicity, current smoking, hypertension, increased systolic blood pressure, prolongation of QRS duration, and higher body mass index and with lower odds of increased ejection fraction (model-generalized R(2) = 0.20). A false-positive ECG-LVH status was associated with lower odds of black race, Hispanic race/ethnicity, minor ST-T abnormalities, increased systolic blood pressure, and presence of any major electrocardiographic abnormalities (model-generalized R(2) = 0.29). Both ECG-LVH and MRI-LVH were associated with an increased risk of cardiovascular disease events (hazard ratio 1.51, 95% confidence interval 1.03 to 2.20 and hazard ratio 1.81, 95% confidence interval 1.33 to 2.46, respectively). In conclusion, discrepancy in LVH detection by ECG and MRI can be relatively improved by considering certain participant characteristics. Discrepancy in diagnostic performance, yet agreement on predictive ability, suggests that LVH by ECG and LVH by imaging are likely to be two distinct but somehow related

  14. The Effect of Study Design Biases on the Diagnostic Accuracy of Magnetic Resonance Imaging to Detect Silicone Breast Implant Ruptures: A Meta-Analysis

    PubMed Central

    Song, Jae W.; Kim, Hyungjin Myra; Bellfi, Lillian T.; Chung, Kevin C.

    2010-01-01

    Background All silicone breast implant recipients are recommended by the US Food and Drug Administration to undergo serial screening to detect implant rupture with magnetic resonance imaging (MRI). We performed a systematic review of the literature to assess the quality of diagnostic accuracy studies utilizing MRI or ultrasound to detect silicone breast implant rupture and conducted a meta-analysis to examine the effect of study design biases on the estimation of MRI diagnostic accuracy measures. Method Studies investigating the diagnostic accuracy of MRI and ultrasound in evaluating ruptured silicone breast implants were identified using MEDLINE, EMBASE, ISI Web of Science, and Cochrane library databases. Two reviewers independently screened potential studies for inclusion and extracted data. Study design biases were assessed using the QUADAS tool and the STARDS checklist. Meta-analyses estimated the influence of biases on diagnostic odds ratios. Results Among 1175 identified articles, 21 met the inclusion criteria. Most studies using MRI (n= 10 of 16) and ultrasound (n=10 of 13) examined symptomatic subjects. Meta-analyses revealed that MRI studies evaluating symptomatic subjects had 14-fold higher diagnostic accuracy estimates compared to studies using an asymptomatic sample (RDOR 13.8; 95% CI 1.83–104.6) and 2-fold higher diagnostic accuracy estimates compared to studies using a screening sample (RDOR 1.89; 95% CI 0.05–75.7). Conclusion Many of the published studies utilizing MRI or ultrasound to detect silicone breast implant rupture are flawed with methodological biases. These methodological shortcomings may result in overestimated MRI diagnostic accuracy measures and should be interpreted with caution when applying the data to a screening population. PMID:21364405

  15. Detection of hepatocellular carcinoma in transgenic mice by Gd-DTPA- and rhodamine 123-conjugated human serum albumin nanoparticles in T1 magnetic resonance imaging.

    PubMed

    Watcharin, Waralee; Schmithals, Christian; Pleli, Thomas; Köberle, Verena; Korkusuz, Hüdayi; Hübner, Frank; Waidmann, Oliver; Zeuzem, Stefan; Korf, Horst-Werner; Terfort, Andreas; Gelperina, Svetlana; Vogl, Thomas J; Kreuter, Jörg; Piiper, Albrecht

    2015-02-10

    Nanoparticle (NP)-based contrast agents that enable high resolution anatomic T1-weighted magnetic resonance imaging (MRI) offer the prospect of improving differential diagnosis of liver tumors such as hepatocellular carcinoma (HCC). In the present study, we investigated the possibility of employing novel non-toxic human serum albumin nanoparticles conjugated with Gd-DTPA and rhodamine 123 (Gd-Rho-HSA-NPs) for the detection of HCC by T1-weighted MRI. In addition, the influence of surface coating of the NPs with poloxamine 908, which alters the absorptive behavior of NPs and changes their distribution between the liver and tumor was examined. MRI of transgenic mice with endogenously formed HCCs following intravenous injection of Gd-Rho-HSA-NPs revealed a strong negative contrast of the tumors. Contrasting of the HCCs by NP-enhanced MRI required less Gd as compared to gadolinium-ethoxybenzyl-diethylenetriaminepentaacetic acid-enhanced MRI, which currently provides the most sensitive detection of HCC in patients. Immunohistochemical analyses revealed that the Gd-Rho-HSA-NPs were localized to macrophages, which were - similar to HCC in patients - fewer in number in HCC as compared to the liver tissue, which is in agreement with the negative contrasting of HCC in Gd-Rho-HSA-NP-enhanced MRI. Poloxamine-coated NPs showed lower accumulation in the tumor macrophages and caused a longer lasting enhancement of the MRI signal. These data indicate that Gd-Rho-HSA-NPs enable sensitive detection of HCC by T1-weighted MRI in mice with endogenous HCC through their uptake by macrophages. Poloxamine coating of the NPs delayed the tumor localization of the NPs. PMID:25499552

  16. Magnetic Resonance Imaging of the Prostate, Including Pre- and Postinterventions.

    PubMed

    Patel, Pritesh; Oto, Aytekin

    2016-09-01

    This article systematically reviews the rationale for magnetic resonance imaging in prostate cancer, in detection and following various treatment methods. A basic discussion of the identification of prostate cancer is imperative to understand postintervention imaging. Each available therapy, including surgery, radiation, hormone therapy, and focal therapies will be discussed along with associated imaging findings, providing the reader with a better understanding of current interventions in prostate cancer and imaging. PMID:27582606

  17. A Novel Approach to Early Detection of Doxorubicin Cardiotoxicity using Gadolinium Enhanced Cardiovascular Magnetic Resonance Imaging in an Experimental Model

    PubMed Central

    Lightfoot, James C.; D'Agostino, Ralph B.; Hamilton, Craig A; Jordan, Jennifer; Torti, Frank M.; Kock, Nancy D.; Jordan, James; Workman, Susan; Hundley, W Gregory

    2011-01-01

    Background To determine if cardiovascular magnetic resonance (CMR) measures of gadolinium (Gd) signal intensity (SI) within the left ventricular (LV) myocardium are associated with future changes in LV ejection fraction (LVEF) after receipt of doxorubicin (DOX). Methods and Results Forty Sprague-Dawley rats were divided into 3 groups scheduled to receive weekly intravenous doses of: normal saline (NS) (n=7), 1.5 mg/kg DOX (n=19), or 2.5 mg/kg DOX (n=14). MR determinations of LVEF and myocardial Gd-SI were performed before and then at 2, 4, 7, and 10 weeks after DOX initiation. During treatment, animals were sacrificed at different time points so that histopathological assessments of the LV myocardium could be obtained. Within group analyses were performed to examine time-dependent relationships between Gd-SI and primary events (a deterioration in LVEF or an unanticipated death). Six of 19 animals receiving 1.5 mg/kg of DOX and 10/14 animals receiving 2.5 mg/kg of DOX experienced a primary event; no NS animals experienced a primary event. In animals with a primary event, histopathological evidence of myocellular vacuolization occurred (p=0.04), and the Gd-SI was elevated relative to baseline at the time of the event (p<0.0001) and during the measurement period prior to the event (p=0.0001). In all animals (including NS) without an event, measures of Gd-SI did not differ from baseline. Conclusions After DOX, low serial measures of Gd-SI predict an absence of a LVEF drop or unanticipated death. An increase in Gd-SI after DOX forecasts a subsequent drop in LVEF as well as histopathologic evidence of intracellular vacuolization consistent with DOX cardiotoxicity. PMID:20622140

  18. Comparison of two fat-suppressed magnetic resonance imaging pulse sequences to standard t2-weighted images for brain parenchymal contrast and lesion detection in dogs with inflammatory intracranial disease.

    PubMed

    Young, Benjamin D; Mankin, Joseph M; Griffin, John F; Fosgate, Geoffrey T; Fowler, Jennifer L; Levine, Jonathan M

    2015-01-01

    T2-weighted (T2w) sequences are commonly relied upon in magnetic resonance imaging protocols for the detection of brain lesions in dogs. Previously, the effect of fluid suppression via fluid-attenuated inversion recovery (FLAIR) has been compared to T2-weighting with mixed results. Short tau inversion recovery (STIR) has been reported to increase the detection of some CNS lesions in people. The purpose of the current study was to evaluate the effect of fat suppression on brain parenchymal contrast resolution and lesion detection in dogs. We compared three sequences: T2w images, STIR, and T2w FLAIR with chemical fat suppression (T2-FLAIR-FS) in dogs with meningoencephalitis. Dogs with meningoencephalitis and dogs with idiopathic epilepsy were retrospectively identified and anonymized. Evaluators recorded the presence or absence of lesions within 12 predetermined brain regions on randomized sequences, viewing and scoring each sequence individually. Additionally, signal-to-noise ratios, contrast-to-noise ratios, and relative contrast (RC) were measured in a reference population. Short tau inversion recovery sequences had the highest RC between gray and white matter. While descriptively more lesions were identified by evaluators on T2-FLAIR-FS images, there was no statistical difference in the relative sensitivity of lesion detection between the sequences. Nor was there a statistical difference in false lesion detection within our reference population. Short tau inversion recovery may be favored for enhanced anatomic contrast depiction in brain imaging. No benefit of the inclusion of a fat-suppressed T2-FLAIR sequence was found. PMID:25395066

  19. Enhancement of Magnetic Resonance Imaging with Metasurfaces.

    PubMed

    Slobozhanyuk, Alexey P; Poddubny, Alexander N; Raaijmakers, Alexander J E; van den Berg, Cornelis A T; Kozachenko, Alexander V; Dubrovina, Irina A; Melchakova, Irina V; Kivshar, Yuri S; Belov, Pavel A

    2016-03-01

    It is revealed that the unique properties of ultrathin metasurface resonators can improve magnetic resonance imaging dramatically. A metasurface formed when an array of metallic wires is placed inside a scanner under the studied object and a substantial enhancement of the radio-frequency magnetic field is achieved by means of subwavelength manipulation with the metasurface, also allowing improved image resolution. PMID:26754827

  20. 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.…

  1. Magnetic resonance imaging of the spine

    SciTech Connect

    Modic, M.

    1988-01-01

    MAGNETIC RESONANCE IMAGING OF THE SPINE thoroughly demonstrates the advantages of this new radiologic modality in diagnosing spinal disorders. The book begins with an introductory chapter on the basic physics and technical considerations of magnetic resonance in general and magnetic resonance imaging of the spine in particular. The second chapter covers normal spinal anatomy, and features color photos of multi-planar sections of spinal anatomy.

  2. Viability, Differentiation Capacity, and Detectability of Super-Paramagnetic Iron Oxide-Labeled Muscle Precursor Cells for Magnetic-Resonance Imaging

    PubMed Central

    Azzabi, Fahd; Rottmar, Markus; Jovaisaite, Virginija; Rudin, Markus; Sulser, Tullio; Boss, Andreas

    2015-01-01

    Cell therapies are a promising approach for the treatment of a variety of human conditions including stress urinary incontinence, but their success greatly depends on the biodistribution, migration, survival, and differentiation of the transplanted cells. Noninvasive in vivo cell tracking therefore presents an important aspect for translation of such a procedure into the clinics. Upon labeling with superparamagnetic iron oxide (SPIO) nanoparticles, cells can be tracked by magnetic resonance imaging (MRI), but possible adverse effect of the labeling have to be considered when labeling stem cells with SPIOs. In this study, human muscle precursor cells (hMPC) were labeled with increasing concentrations of SPIO nanoparticles (100–1600 μg/mL) and cell viability and differentiation capacity upon labeling was assessed in vitro. While a linear dependence between cell viability and nanoparticle concentration could be observed, differentiation capacity was not affected by the presence of SPIOs. Using a nude mouse model, a concentration (400 μg/mL) could be defined that allows reliable detection of hMPCs by MRI but does not influence myogenic in vivo differentiation to mature and functional muscle tissue. This suggests that such an approach can be safely used in a clinical setting to track muscle regeneration in patients undergoing cell therapy without negative effects on the functionality of the bioengineered muscle. PMID:24988198

  3. Imaging and Radiography with Nuclear Resonance Fluorescence and Effective-Z (EZ-3D) Determination; SNM Detection Using Prompt Neutrons from Photon Induced Fission

    SciTech Connect

    Bertozzi, William; Hasty, Richard; Klimenko, Alexei; Korbly, Stephen E.; Ledoux, Robert J.; Park, William

    2009-03-10

    Four new technologies have been developed for use in non-intrusive inspection systems to detect nuclear materials, explosives and contraband. Nuclear Resonance Fluorescence (NRF) provides a three dimensional image of the isotopic content of a container. NRF determines the isotopic composition of a region and specifies the isotopic structure of the neighboring regions, thus providing the detailed isotopic composition of any threat. In transmission mode, NRF provides a two dimensional projection of the isotopic content of a container, much as standard X-ray radiography provides for density. The effective-Z method (EZ-3D) uses electromagnetic scattering processes to yield a three-dimensional map of the effective-Z and the density in a container. The EZ-3D method allows for a rapid discrimination based on effective Z and mass of materials such as those with high Z, as well as specifying regions of interest for other contraband. The energy spectrum of prompt neutrons from photon induced fission (PNPF) provides a unique identification of the presence of actinides and SNM. These four new technologies can be used independently or together to automatically determine the presence of hazardous materials or contraband. They can also be combined with other technologies to provide added specificity.

  4. Imaging and Radiography with Nuclear Resonance Fluorescence and Effective-Z (EZ-3D™) Determination; SNM Detection Using Prompt Neutrons from Photon Induced Fission

    NASA Astrophysics Data System (ADS)

    Bertozzi, William; Hasty, Richard; Klimenko, Alexei; Korbly, Stephen E.; Ledoux, Robert J.; Park, William

    2009-03-01

    Four new technologies have been developed for use in non-intrusive inspection systems to detect nuclear materials, explosives and contraband. Nuclear Resonance Fluorescence (NRF) provides a three dimensional image of the isotopic content of a container. NRF determines the isotopic composition of a region and specifies the isotopic structure of the neighboring regions, thus providing the detailed isotopic composition of any threat. In transmission mode, NRF provides a two dimensional projection of the isotopic content of a container, much as standard X-ray radiography provides for density. The effective-Z method (EZ-3D™) uses electromagnetic scattering processes to yield a three-dimensional map of the effective-Z and the density in a container. The EZ-3D™ method allows for a rapid discrimination based on effective Z and mass of materials such as those with high Z, as well as specifying regions of interest for other contraband. The energy spectrum of prompt neutrons from photon induced fission (PNPF) provides a unique identification of the presence of actinides and SNM. These four new technologies can be used independently or together to automatically determine the presence of hazardous materials or contraband. They can also be combined with other technologies to provide added specificity.

  5. Nonlinear induction detection of electron spin resonance

    NASA Astrophysics Data System (ADS)

    Bachar, Gil; Suchoi, Oren; Shtempluck, Oleg; Blank, Aharon; Buks, Eyal

    2012-07-01

    We present an approach to the induction detection of electron spin resonance (ESR) signals exploiting the nonlinear properties of a superconducting resonator. Our experiments employ a yttrium barium copper oxide superconducting stripline microwave (MW) resonator integrated with a microbridge. A strong nonlinear response of the resonator is thermally activated in the microbridge when exceeding a threshold in the injected MW power. The responsivity factor characterizing the ESR-induced change in the system's output signal is about 100 times larger when operating the resonator near the instability threshold, compared to the value obtained in the linear regime of operation. Preliminary experimental results, together with a theoretical model of this phenomenon are presented. Under appropriate conditions, nonlinear induction detection of ESR can potentially improve upon the current capabilities of conventional linear induction detection ESR.

  6. Nuclear quadrupole resonance detection of explosives: an overview

    NASA Astrophysics Data System (ADS)

    Miller, Joel B.

    2011-06-01

    Nuclear Quadrupole Resonance (NQR) is a spectroscopic technique closely related to Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI). These techniques, and NQR in particular, induce signals from the material being interrogated that are very specific to the chemical and physical structure of the material, but are relatively insensitive to the physical form of the material. NQR explosives detection exploits this specificity to detect explosive materials, in contrast to other well known techniques that are designed to detect explosive devices. The past two decades have seen a large research and development effort in NQR explosives detection in the United States aimed at transportation security and military applications. Here, I will briefly describe the physical basis for NQR before discussing NQR developments over the past decade, with particular emphasis on landmine detection and the use of NQR in combating IED's. Potential future directions for NQR research and development are discussed.

  7. 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.

  8. Concealed weapons detection using electromagnetic resonances

    NASA Astrophysics Data System (ADS)

    Hunt, Allen R.; Hogg, R. Douglas; Foreman, William

    1998-12-01

    Concealed weapons pose a significant threat to both law enforcement and security agency personnel. The uncontrolled environments associated with peacekeeping and the move toward relaxation of concealed weapons laws here in the U.S. provide a strong motivation for developing weapons detection technologies which are noninvasive and can function noncooperatively. Existing weapons detection systems are primarily oriented to detecting metal and require the cooperation of the person being searched. The new generation of detectors under development that focuses primarily on imaging methods, faces problems associated with privacy issues. There remains a need for a weapons detector which is portable, detects weapons remotely, avoids the issues associated with privacy rights, can tell the difference between car keys and a knife, and is affordable enough that one can be issued to every peacekeeper and law enforcement officer. AKELA is developing a concealed weapons detector that uses wideband radar techniques to excite natural electromagnetic resonances that characterize the size, shape, and material composition of an object. Neural network processing is used to classify the difference between weapons and nuisance objects. We have constructed both time and frequency domain test systems and used them to gather experimental data on a variety of armed and unarmed individuals. These experiments have been performed in an environment similar to the operational environment. Preliminary results from these experiments show that it is possible to detect a weapon being carried by an individual from a distance of 10 to 15 feet, and to detect a weapon being concealed behind the back. The power required is about 100 milliwatts. A breadboard system is being fabricated and will be used by AKELA and our law enforcement partner to gather data in operationally realistic situations. While a laptop computer will control the breadboard system, the wideband radar electronics will fit in a box the

  9. Anti-IL-17A treatment reduces clinical score and VCAM-1 expression detected by in vivo magnetic resonance imaging in chronic relapsing EAE ABH mice.

    PubMed

    Mardiguian, Silvy; Serres, Sébastien; Ladds, Emma; Campbell, Sandra J; Wilainam, Panop; McFadyen, Charles; McAteer, Martina; Choudhury, Robin P; Smith, Paul; Saunders, Fay; Watt, Gillian; Sibson, Nicola R; Anthony, Daniel C

    2013-06-01

    IL-17 is argued to play an important role in the multiple sclerosis-like disease experimental autoimmune encephalitis (EAE). We investigated the therapeutic effects of anti-IL-17A in a chronic relapsing EAE ABH mouse model using conventional scoring, quantitative behavioral outcomes, and a novel vascular cell adhesion molecule 1 (VCAM-1)-targeted magnetic resonance imaging (MRI) contrast agent [anti-VCAM-microparticles of iron oxide (MPIO)] to identify conventionally undetectable neuropathology. Mice were administered prophylactic or treatment regimens of anti-IL-17A or IgG and two injections of anti-VCAM-MPIO before undergoing T2*-weighted three-dimensional and gadolinium-diethylenetriamine pentaacetic acid T1-weighted MRI. Rotarod, inverted screen, and open field motor function tests were performed, conventional clinical scores calculated, and central IL-17A mRNA expression quantified during acute disease, remission, and relapse. Prophylactic anti-IL-17A prevents acute disease and relapse and is associated with reduced clinical and functional severity. Treatment regimens delay relapse, improve functional scores, and are associated with reduced VCAM-MPIO lesions during remission. No significant alteration was detectable in levels of gadolinium-diethylenetriamine pentaacetic acid- or VCAM-MPIO-positive lesions during relapse. Prophylactic and treatment anti-IL-17A were therapeutically effective in chronic relapsing EAE, improving clinical and quantifiable functional outcomes. IL-17A expression seems significant during acute disease but less important chronically. Disease-related immunoneuropathology is more sensitively detected using VCAM-MPIO MRI, which may, therefore, be used to monitor therapy meaningfully. PMID:23602647

  10. Anti–IL-17A Treatment Reduces Clinical Score and VCAM-1 Expression Detected by in Vivo Magnetic Resonance Imaging in Chronic Relapsing EAE ABH Mice

    PubMed Central

    Mardiguian, Silvy; Serres, Sébastien; Ladds, Emma; Campbell, Sandra J.; Wilainam, Panop; McFadyen, Charles; McAteer, Martina; Choudhury, Robin P.; Smith, Paul; Saunders, Fay; Watt, Gillian; Sibson, Nicola R.; Anthony, Daniel C.

    2013-01-01

    IL-17 is argued to play an important role in the multiple sclerosis–like disease experimental autoimmune encephalitis (EAE). We investigated the therapeutic effects of anti–IL-17A in a chronic relapsing EAE ABH mouse model using conventional scoring, quantitative behavioral outcomes, and a novel vascular cell adhesion molecule 1 (VCAM-1)–targeted magnetic resonance imaging (MRI) contrast agent [anti–VCAM–microparticles of iron oxide (MPIO)] to identify conventionally undetectable neuropathology. Mice were administered prophylactic or treatment regimens of anti–IL-17A or IgG and two injections of anti–VCAM-MPIO before undergoing T2*-weighted three-dimensional and gadolinium–diethylenetriamine pentaacetic acid T1-weighted MRI. Rotarod, inverted screen, and open field motor function tests were performed, conventional clinical scores calculated, and central IL-17A mRNA expression quantified during acute disease, remission, and relapse. Prophylactic anti–IL-17A prevents acute disease and relapse and is associated with reduced clinical and functional severity. Treatment regimens delay relapse, improve functional scores, and are associated with reduced VCAM-MPIO lesions during remission. No significant alteration was detectable in levels of gadolinium–diethylenetriamine pentaacetic acid– or VCAM-MPIO–positive lesions during relapse. Prophylactic and treatment anti–IL-17A were therapeutically effective in chronic relapsing EAE, improving clinical and quantifiable functional outcomes. IL-17A expression seems significant during acute disease but less important chronically. Disease-related immunoneuropathology is more sensitively detected using VCAM-MPIO MRI, which may, therefore, be used to monitor therapy meaningfully. PMID:23602647

  11. 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

  12. Acoustic resonance for nonmetallic mine detection

    SciTech Connect

    Kercel, S.W.

    1998-04-01

    The feasibility of acoustic resonance for detection of plastic mines was investigated by researchers at the Oak Ridge National Laboratory`s Instrumentation and Controls Division under an internally funded program. The data reported in this paper suggest that acoustic resonance is not a practical method for mine detection. Representative small plastic anti-personnel mines were tested, and were found to not exhibit detectable acoustic resonances. Also, non-metal objects known to have strong acoustic resonances were tested with a variety of excitation techniques, and no practical non-contact method of exciting a consistently detectable resonance in a buried object was discovered. Some of the experimental data developed in this work may be useful to other researchers seeking a method to detect buried plastic mines. A number of excitation methods and their pitfalls are discussed. Excitation methods that were investigated include swept acoustic, chopped acoustic, wavelet acoustic, and mechanical shaking. Under very contrived conditions, a weak response that could be attributed to acoustic resonance was observed, but it does not appear to be practical as a mine detection feature. Transfer properties of soil were investigated. Impulse responses of several representative plastic mines were investigated. Acoustic leakage coupling, and its implications as a disruptive mechanism were investigated.

  13. 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.

  14. 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

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

    DOEpatents

    Engelstad, Barry L.; Raymond, Kenneth N.; Huberty, John P.; White, David L.

    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.

  16. 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

  17. 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

  18. Magnetic resonance imaging of diabetic foot complications.

    PubMed

    Low, Keynes T A; Peh, Wilfred C G

    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

  19. Tumor Detection at 3 Tesla with an Activatable Cell Penetrating Peptide Dendrimer (ACPPD-Gd), a T1 Magnetic Resonance (MR) Molecular Imaging Agent

    PubMed Central

    Malone, Christopher D.; Olson, Emilia S.; Mattrey, Robert F.; Jiang, Tao; Tsien, Roger Y.; Nguyen, Quyen T.

    2015-01-01

    Purpose The ability to detect small malignant lesions with magnetic resonance imaging (MRI) is limited by inadequate accumulations of Gd with standard chelate agents. To date, no T1-targeted agents have proven superiority to Gd chelates in their ability to detect small tumors at clinically relevant field strengths. Activatable cell-penetrating peptides and their Gd-loaded dendrimeric form (ACPPD-Gd) have been shown to selectively accumulate in tumors. In this study we compared the performance of ACPPD-Gd vs. untargeted Gd chelates to detect small tumors in rodent models using a clinical 3T-MR system. Materials and Methods This study was approved by the Institutional-Animal Care-and-Use Committee. 2 of 4 inguinal breast fat pads of 16 albino-C57BL/6 mice were inoculated with tumor Py8119 cells and the other 2 with saline at random. MRI at 3T was performed at 4, 9, and 14 days after inoculation on 8 mice 24-hours after injection of 0.036mmol Gd/kg (ACPPD-Gd), and before and 2–3 minutes after 0.1 mmol/kg gadobutrol on the other 8 mice. T1-weighted (T1w) tumor signal normalized to muscle, was compared among the non-contrast, gadobutrol, and ACPPD-Gd groups using ANOVA. Experienced and trainee readers blinded to experimental conditions assessed for the presence of tumor in each of the 4 breast regions. Receiver operator characteristic (ROC) curves and area-under-curve (AUC) values were constructed and analyzed. Results Tumors ≥1mm3 were iso-intense to muscle without contrast on T1w sequences. They enhanced diffusely and homogeneously by 57±20% (p<0.001) 24 hours after ACPPD-Gd and by 25±13% (p<0.001) immediately after gadobutrol. The nearly 2-fold difference was similar for small tumors (1-5mm3) (45±19% vs. 19±18%, p = 0.03). ACPPD-Gd tended to improve tumor detection by an experienced reader (AUC 0.98 vs 0.91) and significantly more for a trainee (0.93 vs. 0.82, p = 0.02) compared to gadobutrol. This improvement was more pronounced when obvious tumors (>5mm3

  20. The value of magnetic resonance imaging and ultrasonography (MRI/US)-fusion biopsy platforms in prostate cancer detection: a systematic review.

    PubMed

    Gayet, Maudy; van der Aa, Anouk; Beerlage, Harrie P; Schrier, Bart Ph; Mulders, Peter F A; Wijkstra, Hessel

    2016-03-01

    Despite limitations considering the presence, staging and aggressiveness of prostate cancer, ultrasonography (US)-guided systematic biopsies (SBs) are still the 'gold standard' for the diagnosis of prostate cancer. Recently, promising results have been published for targeted prostate biopsies (TBs) using magnetic resonance imaging (MRI) and ultrasonography (MRI/US)-fusion platforms. Different platforms are USA Food and Drug Administration registered and have, mostly subjective, strengths and weaknesses. To our knowledge, no systematic review exists that objectively compares prostate cancer detection rates between the different platforms available. To assess the value of the different MRI/US-fusion platforms in prostate cancer detection, we compared platform-guided TB with SB, and other ways of MRI TB (cognitive fusion or in-bore MR fusion). We performed a systematic review of well-designed prospective randomised and non-randomised trials in the English language published between 1 January 2004 and 17 February 2015, using PubMed, Embase and Cochrane Library databases. Search terms included: 'prostate cancer', 'MR/ultrasound(US) fusion' and 'targeted biopsies'. Extraction of articles was performed by two authors (M.G. and A.A.) and were evaluated by the other authors. Randomised and non-randomised prospective clinical trials comparing TB using MRI/US-fusion platforms and SB, or other ways of TB (cognitive fusion or MR in-bore fusion) were included. In all, 11 of 1865 studies met the inclusion criteria, involving seven different fusion platforms and 2626 patients: 1119 biopsy naïve, 1433 with prior negative biopsy, 50 not mentioned (either biopsy naïve or with prior negative biopsy) and 24 on active surveillance (who were disregarded). The Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool was used to assess the quality of included articles. No clear advantage of MRI/US fusion-guided TBs was seen for cancer detection rates (CDRs) of all prostate

  1. A comparative study of contrast enhanced ultrasound and contrast enhanced magnetic resonance imaging for the detection and characterization of hepatic hemangiomas.

    PubMed

    Fang, Liang; Zhu, Zheng; Huang, Beijian; Ding, Hong; Mao, Feng; Li, Chaolun; Zeng, Mengsu; Zhou, Jianjun; Wang, Ling; Wang, Wenping; Chen, Yue

    2015-04-01

    This study aims to compare contrast enhanced ultrasound (CEUS) and contrast enhanced magnetic resonance imaging (CEMRI) for the detection and characterization of hepatic hemangiomas. Included in this retrospective study were 83 histopathologically confirmed lesions of hemangioma in 66 hospitalized patients who underwent both CEUS and CEMRI and received surgery. The enhancement patterns on CEUS and CEMRI in each lesion were compared and analyzed. In addition, data obtained by the two modalities were then compared with the pathological findings to determine their value in differential diagnosis of hepatic hemangiomas. CEUS diagnosed 78 lesions of hemangioma against 80 by CEMRI. There were no statistical significant differences in the diagnostic value between CEUS and CEMRI in terms of sensitivity (88.0% vs. 92.8%), specificity (99.0% vs. 99.4%), accuracy (97.3% vs. 98.4%), positive predictive value (93.6% vs. 96.3%), and negative predictive value (98.0% vs. 98.8%) (p > 0.05, all). In the arterial phase, the main enhancement pattern on both CEUS and CEMRI was peripheral nodular enhancement (73 vs. 76), but lesions with diffuse enhancement on CEUS outnumbered those on CEMRI (3 vs. 1) and lesions with circular enhancement on CEMRI outnumbered those on CEUS (3 vs. 2). In the portal venous phase and delayed phase, the main enhancement pattern was hyperechoic change on CEUS and hyperintense on CEMRI (66 vs. 65), some lesions presented isoechoic change (12 vs. 15). These results suggested CEUS, an equivalent to CEMRI, may have an added diagnostic value in hemangiomas. PMID:25971695

  2. Differences in Supratentorial Damage of White Matter in Pediatric Survivors of Posterior Fossa Tumors With and Without Adjuvant Treatment as Detected by Magnetic Resonance Diffusion Tensor Imaging

    SciTech Connect

    Rueckriegel, Stefan Mark; Driever, Pablo Hernaiz; Blankenburg, Friederike; Luedemann, Lutz; Henze, Guenter; Bruhn, Harald

    2010-03-01

    Purpose: To elucidate morphologic correlates of brain dysfunction in pediatric survivors of posterior fossa tumors by using magnetic resonance diffusion tensor imaging (DTI) to examine neuroaxonal integrity in white matter. Patients and Methods: Seventeen medulloblastoma (MB) patients who had received surgery and adjuvant treatment, 13 pilocytic astrocytoma (PA) patients who had been treated only with surgery, and age-matched healthy control subjects underwent magnetic resonance imaging on a 3-Tesla system. High-resolution conventional T1- and T2-weighted magnetic resonance imaging and DTI data sets were obtained. Fractional anisotropy (FA) maps were analyzed using tract-based spatial statistics, a part of the Functional MRI of the Brain Software Library. Results: Compared with control subjects, FA values of MB patients were significantly decreased in the cerebellar midline structures, in the frontal lobes, and in the callosal body. Fractional anisotropy values of the PA patients were not only decreased in cerebellar hemispheric structures as expected, but also in supratentorial parts of the brain, with a distribution similar to that in MB patients. However, the amount of significantly decreased FA was greater in MB than in PA patients, underscoring the aggravating neurotoxic effect of the adjuvant treatment. Conclusions: Neurotoxic mechanisms that are present in PA patients (e.g., internal hydrocephalus and damaged cerebellar structures affecting neuronal circuits) contribute significantly to the alteration of supratentorial white matter in pediatric posterior fossa tumor patients.

  3. Magnetic Resonance Imaging for Perianal Fistula.

    PubMed

    Tolan, Damian J M

    2016-08-01

    Perianal fistulas and other inflammatory diseases of the anus and perianal soft tissues are a cause of substantial morbidity, and are a major part of the practice of any colorectal surgeon. Magnetic resonance imaging (MRI) has a key role in the assessment of patients for the extent of fistulizing Crohn disease, complications related to fistulas, and to assist in confirming the diagnosis or proposing an alternative. Technique is critical and in particular, the selection of sequences for diagnosis and characterization of abnormalities with the main choices being between standard anatomical sequences (T1 or T2), assessing for edema (FS T2 or STIR), assessing abnormal contrast enhancement (FS T1), and assessing for abnormal diffusion or a combination of these. Guidance on MRI sequence selection, classification of fistulas, the current guidance on the role of MRI in assessing patients, and advice on how to provide useful structured reports, as well as how to detect complications of perianal sepsis are included. PMID:27342895

  4. Towards Human Oxygen Images with Electron Paramagnetic Resonance Imaging

    PubMed Central

    Epel, Boris; Redler, Gage; Tormyshev, Victor; Halpern, Howard J.

    2016-01-01

    Electron paramagnetic resonance imaging (EPRI) has been used to noninvasively provide 3D images of absolute oxygen concentration (pO2) in small animals. These oxygen images are well resolved both spatially (∼1mm) and in pO2 (1-3 torr). EPRI preclinical images of pO2 have demonstrated extremely promising results for various applications investigating oxygen related physiologic and biologic processes as well as the dependence of various disease states on pO2, such as the role of hypoxia in cancer. Recent developments have been made that help to progress EPRI towards the eventual goal of human application. For example, a bimodal crossed-wire surface coil has been developed. Very preliminary tests demonstrated a 20 dB isolation between transmit and receive for this coil, with an anticipated additional 20dB achievable. This could potentially be used to image local pO2 in human subjects with superficial tumors with EPRI. Local excitation and detection will reduce the specific absorption rate limitations on images and eliminate any possible power deposition concerns. Additionally, a large 9 mT EPRI magnet has been constructed which can fit and provide static main and gradient fields for imaging local anatomy in an entire human. One potential obstacle that must be overcome in order to use EPRI to image humans is the approved use of the requisite EPRI spin probe imaging agent (trityl). While nontoxic, EPRI trityl spin probes have been injected intravenously when imaging small animals, which results in relatively high total body injection doses that would not be suitable for human imaging applications. Work has been done demonstrating the alternative use of intratumoral (IT) injections, which can reduce the amount of trityl required for imaging by a factor of 2000- relative to a whole body intravenous injection. The development of a large magnet that can accommodate human subjects, the design of a surface coil for imaging of superficial pO2, and the reduction of required

  5. Renal relevant radiology: renal functional magnetic resonance imaging.

    PubMed

    Ebrahimi, Behzad; Textor, Stephen C; Lerman, Lilach O

    2014-02-01

    Because of its noninvasive nature and provision of quantitative measures of a wide variety of physiologic parameters, functional magnetic resonance imaging (MRI) shows great potential for research and clinical applications. Over the past decade, application of functional MRI extended beyond detection of cerebral activity, and techniques for abdominal functional MRI evolved. Assessment of renal perfusion, glomerular filtration, interstitial diffusion, and parenchymal oxygenation turned this modality into an essential research and potentially diagnostic tool. Variations in many renal physiologic markers can be detected using functional MRI before morphologic changes become evident in anatomic magnetic resonance images. Moreover, the framework of functional MRI opened a window of opportunity to develop novel pathophysiologic markers. This article reviews applications of some well validated functional MRI techniques, including perfusion, diffusion-weighted imaging, and blood oxygen level-dependent MRI, as well as some emerging new techniques such as magnetic resonance elastography, which might evolve into clinically useful tools. PMID:24370767

  6. Nuclear resonance fluorescence and effective Z determination applied to detection and imaging of special nuclear material, explosives, toxic substances and contraband

    NASA Astrophysics Data System (ADS)

    Bertozzi, William; Korbly, Stephen E.; Ledoux, Robert J.; Park, William

    2007-08-01

    Nuclear resonance fluorescence (NRF) provides a signal that is unique and present for almost all nuclei with Z > 2. This uniqueness would enable, for example, the discrimination between 235U from 238U. Explosives can be detected by the characteristic signatures of carbon, nitrogen and oxygen and their respective densities in a common space. Effective Z algorithms (EZ-3D) have been developed for the examination of the non-resonant spectrum of back-scattered photons that yield a signal with very high contrast between materials of moderately different Z. Both the NRF and EZ-3D non-intrusive inspection techniques provide a three dimensional display of the contents of a container; respectively, the isotopic concentrations, and effective Z and mass. NRF combined with EZ-3D provides the possibility for rapid scanning of seagoing containers, trucks and other vehicles. They do so in short times with high detection probabilities for SNM, explosives and other contraband and with low false alarms.

  7. Fetal magnetic resonance imaging in obstetric practice

    PubMed Central

    Köşüş, Aydın; Köşüş, Nermin; Usluoğulları, Betül; Duran, Müzeyyen; Turhan, Nilgün Öztürk; Tekşam, Mehmet

    2011-01-01

    Ultrasonography (USG) is the primary imaging method for prenatal diagnosis of fetal abnormalities since its discovery. Although it is the primary method of fetal imaging, it cannot provide sufficient information about the fetus in some conditions such as maternal obesity, oligohydramnios and engagement of the fetal head. At this stage, magnetic resonance imaging (MRI) facilitates examination by providing more specific information. The need and importance of fetal MRI applications further increased by the intrauterine surgery which is currently gaining popularity. Some advantages of fetal MRI over USG are the good texture of contrast, a greater study area and visualization of the lesion and neighbourhood relations, independence of the operators. Also it is not affected by maternal obesity and severe oligohydramnios. However, MRI is inadequate in detecting fetal limb and cardiac abnormalities when compared to USG. MRI is not used routinely in pregnancy. It is used in situations where nonionizing imaging methods are inadequate or ionizing radiation is required in pregnant women. It is not recommended during the first trimester. Contrast agent (Godalinium) is not used during pregnancy. It is believed that MRI is not harmful to the fetus, although the biological risk of MRI application is not known. MRI technique is superior to USG in the detection of corpus callosum dysgenesis, third-trimester evaluation of posterior fossa malformations, bilateral renal agenesis, diaphragmatic hernia and assessment of lung maturation. Especially, it is the method of choice for evaluation of central nervous system (CNS) abnormalities. Fetal MRI has a complementary role with USG. It provides important information for prenatal diagnosis, increases diagnostic accuracy, and in turn affects the prenatal treatment, prenatal interventions and birth plan. PMID:24591956

  8. Fetal magnetic resonance imaging in obstetric practice.

    PubMed

    Köşüş, Aydın; Köşüş, Nermin; Usluoğulları, Betül; Duran, Müzeyyen; Turhan, Nilgün Öztürk; Tekşam, Mehmet

    2011-01-01

    Ultrasonography (USG) is the primary imaging method for prenatal diagnosis of fetal abnormalities since its discovery. Although it is the primary method of fetal imaging, it cannot provide sufficient information about the fetus in some conditions such as maternal obesity, oligohydramnios and engagement of the fetal head. At this stage, magnetic resonance imaging (MRI) facilitates examination by providing more specific information. The need and importance of fetal MRI applications further increased by the intrauterine surgery which is currently gaining popularity. Some advantages of fetal MRI over USG are the good texture of contrast, a greater study area and visualization of the lesion and neighbourhood relations, independence of the operators. Also it is not affected by maternal obesity and severe oligohydramnios. However, MRI is inadequate in detecting fetal limb and cardiac abnormalities when compared to USG. MRI is not used routinely in pregnancy. It is used in situations where nonionizing imaging methods are inadequate or ionizing radiation is required in pregnant women. It is not recommended during the first trimester. Contrast agent (Godalinium) is not used during pregnancy. It is believed that MRI is not harmful to the fetus, although the biological risk of MRI application is not known. MRI technique is superior to USG in the detection of corpus callosum dysgenesis, third-trimester evaluation of posterior fossa malformations, bilateral renal agenesis, diaphragmatic hernia and assessment of lung maturation. Especially, it is the method of choice for evaluation of central nervous system (CNS) abnormalities. Fetal MRI has a complementary role with USG. It provides important information for prenatal diagnosis, increases diagnostic accuracy, and in turn affects the prenatal treatment, prenatal interventions and birth plan. PMID:24591956

  9. A preclinical murine model for the early detection of radiation-induced brain injury using magnetic resonance imaging and behavioral tests for learning and memory: with applications for the evaluation of possible stem cell imaging agents and therapies.

    PubMed

    Ngen, Ethel J; Wang, Lee; Gandhi, Nishant; Kato, Yoshinori; Armour, Michael; Zhu, Wenlian; Wong, John; Gabrielson, Kathleen L; Artemov, Dmitri

    2016-06-01

    Stem cell therapies are being developed for radiotherapy-induced brain injuries (RIBI). Magnetic resonance imaging (MRI) offers advantages for imaging transplanted stem cells. However, most MRI cell-tracking techniques employ superparamagnetic iron oxide particles (SPIOs), which are difficult to distinguish from hemorrhage. In current preclinical RIBI models, hemorrhage occurs concurrently with other injury markers. This makes the evaluation of the recruitment of transplanted SPIO-labeled stem cells to injury sites difficult. Here, we developed a RIBI model, with early injury markers reflective of hippocampal dysfunction, which can be detected noninvasively with MRI and behavioral tests. Lesions were generated by sub-hemispheric irradiation of mouse hippocampi with single X-ray beams of 80 Gy. Lesion formation was monitored with anatomical and contrast-enhanced MRI and changes in memory and learning were assessed with fear-conditioning tests. Early injury markers were detected 2 weeks after irradiation. These included an increase in the permeability of the blood-brain barrier, demonstrated by a 92 ± 20 % contrast enhancement of the irradiated versus the non-irradiated brain hemispheres, within 15 min of the administration of an MRI contrast agent. A change in short-term memory was also detected, as demonstrated by a 40.88 ± 5.03 % decrease in the freezing time measured during the short-term memory context test at this time point, compared to that before irradiation. SPIO-labeled stem cells transplanted contralateral to the lesion migrated toward the lesion at this time point. No hemorrhage was detected up to 10 weeks after irradiation. This model can be used to evaluate SPIO-based stem cell-tracking agents, short-term. PMID:27021492

  10. Segmentation of neuroanatomy in magnetic resonance images

    NASA Astrophysics Data System (ADS)

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

    1992-06-01

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

  11. Magnetic resonance imaging of benign prostatic hyperplasia

    PubMed Central

    Guneyli, Serkan; Ward, Emily; Thomas, Stephen; Yousuf, Ambereen Nehal; Trilisky, Igor; Peng, Yahui; Antic, Tatjana; Oto, Aytekin

    2016-01-01

    Benign prostatic hyperplasia (BPH) is a common condition in middle-aged and older men and negatively affects the quality of life. An ultrasound classification for BPH based on a previous pathologic classification was reported, and the types of BPH were classified according to different enlargement locations in the prostate. Afterwards, this classification was demonstrated using magnetic resonance imaging (MRI). The classification of BPH is important, as patients with different types of BPH can have different symptoms and treatment options. BPH types on MRI are as follows: type 0, an equal to or less than 25 cm3 prostate showing little or no zonal enlargements; type 1, bilateral transition zone (TZ) enlargement; type 2, retrourethral enlargement; type 3, bilateral TZ and retrourethral enlargement; type 4, pedunculated enlargement; type 5, pedunculated with bilateral TZ and/or retrourethral enlargement; type 6, subtrigonal or ectopic enlargement; type 7, other combinations of enlargements. We retrospectively evaluated MRI images of BPH patients who were histologically diagnosed and presented the different types of BPH on MRI. MRI, with its advantage of multiplanar imaging and superior soft tissue contrast resolution, can be used in BPH patients for differentiation of BPH from prostate cancer, estimation of zonal and entire prostatic volumes, determination of the stromal/glandular ratio, detection of the enlargement locations, and classification of BPH types which may be potentially helpful in choosing the optimal treatment. PMID:27015442

  12. 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.

  13. 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

  14. Approach to breast magnetic resonance imaging interpretation.

    PubMed

    Palestrant, Sarah; Comstock, Christopher E; Moy, Linda

    2014-05-01

    With the increasing use of breast magnetic resonance (MR) imaging comes the expectation that the breast radiologist is as fluent in its interpretation as in that of mammography and breast ultrasonography. Knowledge of who should be included for imaging and how to perform the imaging are as essential as interpreting the images. When reading the examination, the radiologist should approach the images from both a global and focused perspective, synthesizing findings into a report that includes a management plan. This article reviews a systematic and organized approach to breast MR imaging interpretation. PMID:24792657

  15. 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)

  16. 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…

  17. Force detected electron spin resonance at 94 GHz.

    PubMed

    Cruickshank, Paul A S; Smith, Graham M

    2007-01-01

    Force detected electron spin resonance (FDESR) detects the presence of unpaired electrons in a sample by measuring the change in force on a mechanical resonator as the magnetization of the sample is modulated under magnetic resonance conditions. The magnetization is coupled to the resonator via a magnetic field gradient. It has been used to both detect and image distributions of electron spins, and it offers both extremely high absolute sensitivity and high spatial imaging resolution. However, compared to conventional induction mode ESR the technique also has a comparatively poor concentration sensitivity and it introduces complications in interpreting and combining both spectroscopy and imaging. One method to improve both sensitivity and spectral resolution is to operate in high magnetic fields in order to increase the sample magnetization and g-factor resolution. In this article we present FDESR measurements on the organic conductor (fluoranthene)(2)PF(6) at 3.2 T, with a corresponding millimeter-wave frequency of 93.5 GHz, which we believe are the highest field results for FDESR reported in the literature to date. A magnet-on-cantilever approach was used, with a high-anisotropy microwave ferrite as the gradient source and employing cyclic saturation to modulate the magnetization at the cantilever fundamental frequency. PMID:17503940

  18. Artifacts in Breast Magnetic Resonance Imaging.

    PubMed

    Anthony, Marina-Portia; Nguyen, Dustin; Friedlander, Lauren; Mango, Victoria; Wynn, Ralph; Ha, Richard

    2016-01-01

    As breast magnetic resonance imaging has evolved to become a routine part of clinical practice, so too has the need for radiologists to be aware of its potential pitfalls and limitations. Unique challenges arise in the identification and remedy of artifacts in breast magnetic resonance imaging, and it is important that radiologists and technicians work together to optimize protocols and monitor examinations such that these may be minimized or avoided entirely. This article presents patient-related and technical artifacts that may give rise to reduced image quality and ways to recognize and reduce them. PMID:26343534

  19. Significance of Coronal Proset Magnetic Resonance Imaging to Detect Hidden Zone of the Mid-Zone Stenosis in the Lumbar Spine and Morphometric Analysis of the Mid-Zone Stenosis

    PubMed Central

    Ahn, Hyo-Sae; Son, Whee Sung; Shin, Ji-Hoon; Ahn, Myun-Whan

    2016-01-01

    Study Design Retrospective exploratory imaging study. Purpose To investigate the significance of the coronal magnetic resonance imaging (MRI) using Proset technique to detect the hidden zone in patients with mid-zone stenosis by comparing with conventional axial and sagittal MRI and to explore the morphologic characteristic patterns of the mid-zone stenosis. Overview of Literature Despite advancements in diagnostic modalities such as computed tomography and MRI, stenotic lesions under the pedicle and pars interarticularis, also called the mid-zone, are still difficult to definitely detect with the conventional axial and sagittal MRI due to its inherited anatomical peculiarity. Methods Of 180 patients scheduled to undergo selective nerve root block, 20 patients with mid-zone stenosis were analyzed using MRI. Characteristic group patterns were also explored morphologically by comparing MRI views of each group after verifying statistical differences between them. Hierarchical cluster analysis was performed to classify morphological characteristic groups based on three-dimensional radiologic grade for stenosis at all three zones. Results At the mid-zone, the stenosis of grade 2 or more was found in 14 cases in the coronal image,13 cases in the sagittal image, and 9 cases in the axial image (p<0.05). Especially, mid-zone stenosis was not detected in six of 20 cases at the axial images. At the entrance and exit-zone, coronal image was also associated with more accurate detection of hidden zone compared to other views such as axial and sagittal images. After repeated statistical verification, the morphological patterns of hidden zone were classified into 5 groups: 6 cases in group I; 1 case in group II; 4 cases in group III; 7 cases in group IV; and 2 cases in group V. Conclusions Coronal MRI using the Proset technique more accurately detected hidden zone of the mid-zone stenosis compared to conventional axial and sagittal images. PMID:27559443

  20. 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.

  1. Tutte polynomial in functional magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    García-Castillón, Marlly V.

    2015-09-01

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

  2. 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.

  3. Accelerated nanoscale magnetic resonance imaging through phase multiplexing

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    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 (1H, 19F) 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.

  4. Pelvic applications of diffusion magnetic resonance images.

    PubMed

    Coutinho, Antonio C; Krishnaraj, Arun; Pires, Cintia E; Bittencourt, Leonardo K; Guimarães, Alexander R

    2011-02-01

    Diffusion-weighted imaging (DWI) is a powerful imaging technique in neuroimaging; its value in abdominal and pelvic imaging has only recently been appreciated as a result of improvements in magnetic resonance imaging technology. There is growing interest in the use of DWI for evaluating pathology in the pelvis. Its ability to noninvasively characterize tissues and to depict changes at a cellular level allows DWI to be an effective complement to conventional sequences of pelvic imaging, especially in oncologic patients. The addition of DWI may obviate contrast material in those with renal insufficiency or contrast material allergy. PMID:21129639

  5. Comparing the Detectability of Hepatocellular Carcinoma by C-Arm Dual-Phase Cone-Beam Computed Tomography During Hepatic Arteriography With Conventional Contrast-Enhanced Magnetic Resonance Imaging

    SciTech Connect

    Loffroy, Romaric; Lin, MingDe; Rao, Pramod; Bhagat, Nikhil; Noordhoek, Niels; Radaelli, Alessandro; Blijd, Jaerl; Geschwind, Jean-Francois

    2012-02-15

    Purpose: To evaluate the sensitivity of dual-phase cone-beam computed tomography during hepatic arteriography (CBCTHA) for the detection of hepatocellular carcinoma (HCC) by comparing it with the diagnostic imaging 'gold standard': contrast-enhanced magnetic resonance imaging (CE-MRI) of the liver. Materials and Methods: Eighty-eight HCC lesions (mean diameter 3.9 {+-} 3.3 cm) in 20 patients (13 men, mean age 61.4 years [range 50 to 80]), who sequentially underwent baseline diagnostic liver CE-MRI and then underwent early arterial- and delayed portal venous-phase CBCTHA during drug eluting-bead transarterial chemoembolization, were evaluated. Dual-phase CBCTHA findings of each tumor in terms of conspicuity were compared with standard CE-MR images and classified into three grades: optimal, suboptimal, and nondiagnostic. Results: Seventy-seven (mean diameter 4.2 {+-} 3.4 cm [range 0.9 to 15.9]) (93.9%) of 82 tumors were detected. Sensitivity of arterial-phase (71.9%) was lower than that of venous-phase CBCTHA (86.6%) for the detection of HCC lesions. Of the 82 tumors, 33 (40.2%) and 52 (63.4%), 26 (31.7%) and 19 (23.2%), and 23 (28%) and 11 (13.4%) nodules were classed as optimal, suboptimal, and nondiagnostic on arterial- and venous-phase CBCTHA images, respectively. Seventeen (73.9%) of the 23 tumors that were not visible on arterial phase were detected on venous phase. Six (54.5%) of the 11 tumors that were not visible on venous phase were detected on arterial phase. Conclusions: Dual-phase CBCTHA has sufficient image quality to detect the majority of HCC lesions compared with the imaging 'gold standard': CE-MRI of the liver. Moreover, dual-phase CBCTHA is more useful and reliable than single-phasic imaging to depict HCC nodules.

  6. High resolution resonance ionization imaging detector and method

    DOEpatents

    Winefordner, James D.; Matveev, Oleg I.; Smith, Benjamin W.

    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.

  7. Quadrupole resonance scanner for narcotics detection

    NASA Astrophysics Data System (ADS)

    Shaw, Julian D.; Moeller, C. R.; Magnuson, Erik E.; Sheldon, Alan G.

    1994-10-01

    Interest in non-invasive, non-hazardous, bulk detection technologies for narcotics interdiction has risen over the last few years. As part of our continuing research and development programs in detection of narcotics and explosives using sensitive magnetic measuring devices, we present the first commercially available prototype Quadrupole Resonance (QR) scanner for narcotics detection. The portable narcotics detection system was designed in modular form such that a single QR base system could be easily used with a variety of custom detection heads. The QR system presented in this paper is suitable for scanning items up to 61 X 35 X 13 cm in size, and was designed to scan mail packages and briefcase-sized items for the presence of narcotics. System tests have shown that detection sensitivity is comparable that obtained in laboratory systems.

  8. 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

  9. 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

  10. Emergency Magnetic Resonance Imaging of Musculoskeletal Trauma.

    PubMed

    Kumaravel, Manickam; Weathers, William M

    2016-05-01

    Musculoskeletal (MSK) trauma is commonly encountered in the emergency department. Computed tomography and radiography are the main forms of imaging assessment, but the use of magnetic resonance (MR) imaging has become more common in the emergency room (ER) setting for evaluation of low-velocity/sports-related injury and high-velocity injury. The superior soft tissue contrast and detail provided by MR imaging gives clinicians a powerful tool in the management of acute MSK injury in the ER. This article provides an overview of techniques and considerations when using MR imaging in the evaluation of some of the common injuries seen in the ER setting. PMID:27150325

  11. 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.

  12. Magnetic resonance imaging for the study of mummies.

    PubMed

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

    2016-07-01

    Nondestructive diagnostic imaging for mummies study has a long tradition and high-resolution images of the samples morphology have been extensively acquired by using computed tomography (CT). However, although in early reports no signal or image was obtained because of the low water content, mummy magnetic resonance imaging (MRI) was demonstrated able to generate images of such ancient specimens by using fast imaging techniques. Literature demonstrated the general feasibility of nonclinical MRI for visualizing historic human tissues, which is particularly interesting for archeology. More recently, multinuclear magnetic resonance spectroscopy (MRS) was demonstrated able to detect numerous organic biochemicals from such remains. Although the quality of these images is not yet comparable to that of clinical magnetic resonance (MR) images, and further research will be needed for determining the full capacity of MR in this topic, the information obtained with MR can be viewed as complementary to the one provided by CT and useful for paleoradiological studies of mummies. This work contains an overview of the state of art of the emerging uses of MRI in paleoradiology. PMID:26979539

  13. Broadband Resonant Mass Gravitational Wave Detection

    NASA Astrophysics Data System (ADS)

    Aguiar, Odylio D.; Barroso, Joaquim J.; Marinho, Rubens M.; Pimentel, Guilherme L.; Tobar, Michael E.

    By changing from a resonant multimode paradigm to a free mass paradigm for transducers in resonant mass gravitational wave detection, an array of six spheres can achieve a sensitivity response curve competitive with interferometers, being as sensitive as GEO600 and TAMA300 in the 3-6 kHz band and more sensitive than LIGO for 50% of the 6-10 kHz band. This approach has additional benefits. First, due to the relatively inexpensive nature of this technology (~US$1 million), it is accessible to a broader part of the world's scientific community. Additionally, spherical resonant mass detectors have the ability to discern both the direction and polarization resolutions.

  14. 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

  15. Neurosurgical uses for intraprocedural magnetic resonance imaging.

    PubMed

    Mutchnick, Ian S; Moriarty, Thomas M

    2005-10-01

    Neurosurgical procedures demand precision, and efforts to create accurate neurosurgical navigation have been central to the profession through its history. Magnetic resonance image (MRI)-guided navigation offers the possibility of real-time, image-based stereotactic information for the neurosurgeon, which makes possible a number of diagnostic and therapeutic procedures. This article will review both current options for intraoperative MRI operative suite arrangements and the current therapeutic/diagnostic uses of intraoperative MRI. PMID:16924171

  16. Rapid serodiagnosis with the use of surface plasmon resonance imaging for the detection of antibodies against major surface protein A of Mycoplasma synoviae in chickens.

    PubMed

    Oh, Kiseok; Lee, Semi; Seo, Jayoung; Lee, Dongwoo; Kim, Taejung

    2010-01-01

    Mycoplasma synoviae, a major worldwide pathogen in poultry, causes respiratory tract infection and arthritis in chickens and turkeys. Two major surface antigens of M. synoviae are encoded by a single gene, vlhA (variably expressed lipoprotein and hemagglutinin). The gene product is cleaved post-translationally to yield the lipoprotein major surface protein (MSP) B (MSPB) and the hemagglutinin MSPA. The availability of MSPA as an antigen for serodiagnosis was studied by means of a protein chip based on surface plasmon resonance imaging (SPRi). The diagnostic potential of SPRi for measurement of levels of antibody to MSPA was compared with that of a conventional enzyme-linked immunosorbent assay (ELISA) kit. The results from SPRi, a process that took only 1 h, were similar to those from ELISA. Therefore, MSPA can be used as an antigen for serologic studies, and SPRi, a label-free and high-throughput method, may be a valuable tool in avian serodiagnostic studies. PMID:20357963

  17. Magnetic resonance force detection using a membrane resonator

    NASA Astrophysics Data System (ADS)

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

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

  18. 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

  19. 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

  20. Magnetic Resonance Imaging of Pituitary Tumors.

    PubMed

    Bonneville, Jean-François

    2016-01-01

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

  1. Sports Health Magnetic Resonance Imaging Challenge

    PubMed Central

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

    2010-01-01

    Injuries to the Lisfranc ligament complex are often suspected, particularly in the setting of midfoot pain without radiographic abnormality. Knowledge of the anatomy and magnetic resonance imaging findings of injuries to this region is helpful for the diagnosing and treating physicians. PMID:23015984

  2. Magnetic resonance imaging of the central nervous system

    SciTech Connect

    Brant-Zawadzki, M.; Norman, D.

    1987-01-01

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

  3. Magnetic Resonance Imaging in ADNI

    PubMed Central

    Jack, Clifford R.; Barnes, Josephine; Bernstein, Matt A.; Borowski, Bret J.; Brewer, James; Clegg, Shona; Dale, Anders M.; Carmichael, Owen; Ching, Christopher; DeCarli, Charles; Desikan, Rahul S.; Fennema-Notestine, Christine; Fjell, Anders M.; Fletcher, Evan; Fox, Nick C.; Gunter, Jeff; Gutman, Boris A.; Holland, Dominic; Hua, Xue; Insel, Philip; Kantarci, Kejal; Killiany, Ron J.; Krueger, Gunnar; Leung, Kelvin K.; Mackin, Scott; Maillard, Pauline; Molone, Ian; Mattsson, Niklas; McEvoy, Linda; Modat, Marc; Mueller, Susanne; Nosheny, Rachel; Ourselin, Sebastien; Schuff, Norbert; Senjem, Matthew L.; Simonson, Alix; Thompson, Paul M.; Rettmann, Dan; Vemuri, Prashanthi; Walhovd, Kristine; Zhao, Yansong; Zuk, Samantha; Weiner, Michael

    2015-01-01

    INTRODUCTION ADNI is now in its 10th year. The primary objective of the MRI core of ADNI has been to improve methods for clinical trials in Alzheimer’s disease and related disorders. METHODS We review the contributions of the MRI core from present and past cycles of ADNI (ADNI 1, GO and 2). We also review plans for the future – ADNI 3. RESULTS Contributions of the MRI core include creating standardized acquisition protocols and quality control methods; examining the effect of technical features of image acquisition and analysis on outcome metrics; deriving sample size estimates for future trials based on those outcomes; and piloting the potential utility of MR perfusion, diffusion, and functional connectivity measures in multicenter clinical trials. DISCUSSION Over the past decade the MRI core of ADNI has fulfilled its mandate of improving methods for clinical trials in Alzheimer’s disease and will continue to do so in the future. PMID:26194310

  4. PLUTINO DETECTION BIASES, INCLUDING THE KOZAI RESONANCE

    SciTech Connect

    Lawler, S. M.; Gladman, B.

    2013-07-01

    Because of their relative proximity within the trans-Neptunian region, the plutinos (objects in the 3:2 mean-motion resonance with Neptune) are numerous in flux-limited catalogs, and well-studied theoretically. We perform detailed modeling of the on-sky detection biases for plutinos, with special attention to those that are simultaneously in the Kozai resonance. In addition to the normal 3:2 resonant argument libration, Kozai plutinos also show periodic oscillations in eccentricity and inclination, coupled to the argument of perihelion ({omega}) oscillation. Due to the mean-motion resonance, plutinos avoid coming to pericenter near Neptune's current position in the ecliptic plane. Because Kozai plutinos are restricted to certain values of {omega}, perihelion always occurs out of the ecliptic plane, biasing ecliptic surveys against finding these objects. The observed Kozai plutino fraction f{sub koz}{sup obs} has been measured by several surveys, finding values between 8% and 25%, while the true Kozai plutino fraction f{sub koz}{sup true} has been predicted to be between 10% and 30% by different giant planet migration simulations. We show that f{sub koz}{sup obs} varies widely depending on the ecliptic latitude and longitude of the survey, so debiasing to find the true ratio is complex. Even a survey that covers most or all of the sky will detect an apparent Kozai fraction that is different from f{sub koz}{sup true}. We present a map of the on-sky plutino Kozai fraction that would be detected by all-sky flux-limited surveys. This will be especially important for the Panoramic Survey Telescope and Rapid Response System and Large Synoptic Survey Telescope projects, which may detect large numbers of plutinos as they sweep the sky. f{sub koz}{sup true} and the distribution of the orbital elements of Kozai plutinos may be a diagnostic of giant planet migration; future migration simulations should provide details on their resonant Kozai populations.

  5. Terahertz imaging system with resonant tunneling diodes

    NASA Astrophysics Data System (ADS)

    Miyamoto, Tomoyuki; Yamaguchi, Atsushi; Mukai, Toshikazu

    2016-03-01

    We report a feasibility study of a terahertz imaging system with resonant tunneling diodes (RTDs) that oscillate at 0.30 THz. A pair of RTDs acted as an emitter and a detector in the system. Terahertz reflection images of opaque samples were acquired with our RTD imaging system. A spatial resolution of 1 mm, which is equal to the wavelength of the RTD emitter, was achieved. The signal-to-noise ratio (SNR) of the reflection image was improved by 6 dB by using polarization optics that reduced interference effects. Additionally, the coherence of the RTD enabled a depth resolution of less than 3 µm to be achieved by an interferometric technique. Thus, RTDs are an attractive candidate for use in small THz imaging systems.

  6. Magnetic Resonance Imaging by Synergistic Diffusion-Diffraction Patterns

    NASA Astrophysics Data System (ADS)

    Shemesh, Noam; Westin, Carl-Fredrik; Cohen, Yoram

    2012-02-01

    Inferring on the geometry of an object from its frequency spectrum is highly appealing since the object could then be imaged noninvasively or from a distance (as famously put by Kac, “can one hear the shape of a drum?”). In nuclear magnetic resonance of porous systems, the shape of the drum is represented by the pore density function that bears all the information on the collective pore microstructure. So far, conventional magnetic resonance imaging (MRI) could only detect the pore autocorrelation function, which inherently obscures fine details on the pore structure. Here, for the first time, we report on a unique imaging mechanism arising from synergistic diffusion-diffractions that directly yields the pore density function. This mechanism offers substantially higher spatial resolution compared to conventional MRI while retaining all fine details on the collective pore morphology. Thus, using these unique synergistic diffusion-diffractions, the “shape of the drum” can be inferred.

  7. Magnetic resonance imaging using linear magneto-inductive waveguides

    NASA Astrophysics Data System (ADS)

    Syms, R. R. A.; Young, I. R.; Ahmad, M. M.; Rea, M.

    2012-12-01

    Magneto-inductive waveguides are arrays of magnetically coupled, lumped element resonators, which support slow waves at radio frequency. Their use in internal magnetic resonance imaging (MRI), where they may provide an intrinsically safe method of signal detection and transmission, is described. A catheter-based receiver formed from a thin-film printed circuit mounted on a tubular scaffold using heat-shrink tubing is demonstrated, and its electrical response and imaging sensitivity are explained in terms of the excitation and propagation of magneto-inductive waves. The theoretical predictions are confirmed using the results of electrical measurement and 1H MRI at 1.5 T, and imaging is achieved over a total length greater than 1.5 m using a single receiver.

  8. 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.

  9. Volume coil based on hybridized resonators for magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Jouvaud, C.; Abdeddaim, R.; Larrat, B.; de Rosny, J.

    2016-01-01

    We present an electromagnetic device based on hybridization of four half-wavelength dipoles which increases the uniformity and the strength of the radio-frequency (RF) field of a Magnetic Resonant Imaging (MRI) apparatus. Numerical results show that this Hybridized Coil (HC) excited with a classical loop coil takes advantage of the magnetic hybrid modes. The distribution of the RF magnetic field is experimentally confirmed on a 7-T MRI with a gelatin phantom. Finally, the HC is validated in vivo by imaging the head of an anesthetized rat. We measure an overall increase of the signal to noise ratio with up to 2.4 fold increase in regions of interest far from the active loop coil.

  10. Osteomyelitis in children: detection by magnetic resonance: work in progress

    SciTech Connect

    Fletcher, B.D.; Scoles, P.V.; Nelson, A.D.

    1984-01-01

    Magnetic resonance (MR) imaging was performed in five children, ages 9 to 12, with acute, subacute, chronic, and recurrent osteomyelitis. Saturation recovery (SR), T2-weighted spin echo, and inversion recovery (IR) pulse sequences were employed. A reduction in the normally bright image of bone marrow corresponded with abnormalities seen on radiographs, CT scans, and radionuclide scans. SR images produced the best signal-to-noise ratios. Contrast between normal and abnormal marrow was most pronounced on IR sequences, which suggested an increase in water content of inflamed marrow. Abnormalities were sometimes seen on MR images before they could be detected on radiographs. Some MR abnormalities were present when CT and radionuclide studies were normal or equivocal.

  11. Magnetic resonance imaging--first human images in Australia.

    PubMed

    Baddeley, H; Doddrell, D M; Brooks, W M; Field, J; Irving, M; Williams, J E

    1986-10-20

    The use of magnetic resonance imaging, in the demonstration of internal human anatomy and in the diagnosis of disease, has the major advantages that the technique is noninvasive, does not require the use of ionizing radiation and that it can demonstrate neurological and cardiovascular lesions that cannot be diagnosed easily by other imaging methods. Magnetic resonance imaging is derived from the principle that certain atomic nuclei in a strong magnetic field will absorb pulses of radiofrequency energy; when the pulse is finished the nuclei will emit radiowaves at the same frequency. These radiowaves are received by specially designed aerials or coils and the information is collected by a computer which reconstructs an image of internal anatomy in a similar way to that of x-ray computed tomography (CT). By changing the strength of the magnetic fields and the frequency of the radiowave pulses, it is possible to examine different sections within the body. The first magnetic resonance images of humans were obtained in Australia in October 1985 on the research instrument of the Queensland Medical Magnetic Resonance Research Centre, which is based at the Mater Hospital in Brisbane, and is part of the University of Queensland's Department of Radiology. PMID:3020385

  12. Detecting clandestine material with nuclear resonance fluorescence

    NASA Astrophysics Data System (ADS)

    Pruet, J.; McNabb, D. P.; Hagmann, C. A.; Hartemann, F. V.; Barty, C. P. J.

    2006-06-01

    We study the performance of a class of interrogation systems that exploit nuclear resonance fluorescence (NRF) to detect specific isotopes. In these systems the presence of a particular nuclide is inferred by observing the preferential attenuation of photons that strongly excite an electromagnetic transition in that nuclide. Estimates for the false positive/negative error rates, radiological dose, and detection sensitivity associated with discovering clandestine material embedded in cargo are presented. The relation between performance of the detection system and properties of the beam of interrogating photons is also considered. Bright gamma-ray sources with fine energy and angular resolution, such as those based on Thomson upscattering of laser light, are found to be associated with uniquely low radiological dose, scan times, and error rates. For this reason a consideration of NRF-based interrogation systems may provide impetus for efforts in light source development for applications related to national security and industry.

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

    PubMed Central

    Lin, Fa-Hsuan; Witzel, Thomas; Zeffiro, Thomas A.; Belliveau, John W.

    2011-01-01

    Accurate estimation of the timing of neural activity is required to fully model the information flow among functionally specialized regions whose joint activity underlies perception, cognition and action. Attempts to detect the fine temporal structure of task-related activity would benefit from functional imaging methods allowing higher sampling rates. Spatial filtering techniques have been used in magnetoencephalography source imaging applications. In this work, we use the linear constraint minimal variance (LCMV) beamformer localization method to reconstruct single-shot volumetric functional magnetic resonance imaging (fMRI) data using signals acquired simultaneously from all channels of a high density radio-frequency (RF) coil array. The LCMV beamformer method generalizes the existing volumetric magnetic resonance inverse imaging (InI) technique, achieving higher detection sensitivity while maintaining whole-brain spatial coverage and 100 ms temporal resolution. In this paper, we begin by introducing the LCMV reconstruction formulation and then quantitatively assess its performance using both simulated and empirical data. To demonstrate the sensitivity and inter-subject reliability of volumetric LCMV InI, we employ an event-related design to probe the spatial and temporal properties of task-related hemodynamic signal modulations in primary visual cortex. Compared to minimum-norm estimate (MNE) reconstructions, LCMV offers better localization accuracy and superior detection sensitivity. Robust results from both single subject and group analyses demonstrate the excellent sensitivity and specificity of volumetric InI in detecting the spatial and temporal structure of task-related brain activity. PMID:18672071

  14. 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.

  15. A Novel Diagnostic Aid for Detection of Intra-Abdominal Adhesions to the Anterior Abdominal Wall Using Dynamic Magnetic Resonance Imaging

    PubMed Central

    Randall, David; Fenner, John; Gillott, Richard; ten Broek, Richard; Strik, Chema; Spencer, Paul; Bardhan, Karna Dev

    2016-01-01

    Introduction. Abdominal adhesions can cause serious morbidity and complicate subsequent operations. Their diagnosis is often one of exclusion due to a lack of a reliable, non-invasive diagnostic technique. Development and testing of a candidate technique are described below. Method. During respiration, smooth visceral sliding motion occurs between the abdominal contents and the walls of the abdominal cavity. We describe a technique involving image segmentation and registration to calculate shear as an analogue for visceral slide based on the tracking of structures throughout the respiratory cycle. The presence of an adhesion is attributed to a resistance to visceral slide resulting in a discernible reduction in shear. The abdominal movement due to respiration is captured in sagittal dynamic MR images. Results. Clinical images were selected for analysis, including a patient with a surgically confirmed adhesion. Discernible reduction in shear was observed at the location of the adhesion while a consistent, gradually changing shear was observed in the healthy volunteers. Conclusion. The technique and its validation show encouraging results for adhesion detection but a larger study is now required to confirm its potential. PMID:26880884

  16. Multiparametric Magnetic Resonance Imaging of Recurrent Prostate Cancer.

    PubMed

    Mertan, Francesca V; Greer, Matthew D; Borofsky, Sam; Kabakus, Ismail M; Merino, Maria J; Wood, Bradford J; Pinto, Peter A; Choyke, Peter L; Turkbey, Baris

    2016-06-01

    There is growing consensus that multiparametric magnetic resonance imaging (mpMRI) is an effective modality in the detection of locally recurrent prostate cancer after prostatectomy and radiation therapy. The emergence of magnetic resonance (MR)-guided focal therapies, such as cryoablation, high-intensity focused ultrasound, and laser ablation, have made the use of mpMRI even more important, as the normal anatomy is inevitably altered and the detection of recurrence is made more difficult. The aim of this article is to review the utility of mpMRI in detecting recurrent prostate cancer in patients following radical prostatectomy, radiation therapy, and focal therapy and to discuss expected post-treatment mpMRI findings, the varied appearance of recurrent tumors, and their mimics. PMID:27187164

  17. Manganese-Enhanced Magnetic Resonance Imaging for Detection of Vasoactive Intestinal Peptide Receptor 2 Agonist Therapy in a Model of Parkinson's Disease.

    PubMed

    Olson, Katherine E; Bade, Aditya N; Schutt, Charles R; Dong, Jingdong; Shandler, Scott J; Boska, Michael D; Mosley, R Lee; Gendelman, Howard E; Liu, Yutong

    2016-07-01

    Neuroprotective immunity is defined by transformation of T-cell polarity for therapeutic gain. For neurodegenerative disorders and specifically for Parkinson's disease (PD), granulocyte-macrophage colony stimulating factor or vasoactive intestinal peptide receptor 2 (VIPR2) agonists elicit robust anti-inflammatory microglial responses leading to neuronal sparing in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-intoxicated mice. While neurotherapeutic potential was demonstrated for PD, there remain inherent limitations in translating these inventions from the laboratory to patients. One obstacle in translating such novel neurotherapeutics centers on the availability of suitable noninvasive methods to track disease progression and therapeutic efficacy. To this end, we developed manganese-enhanced magnetic resonance imaging (MEMRI) assays as a way to track a linkage between glial activation and VIPR2 agonist (LBT-3627)-induced neuroprotective immunity for MPTP-induced nigrostriatal degeneration. Notably, LBT-3627-treated, MPTP-intoxicated mice show reduced MEMRI brain signal intensities. These changes paralleled reduced astrogliosis and resulted in sparing of nigral tyrosine hydroxylase neurons. Most importantly, the data suggest that MEMRI can be developed as a biomarker tool to monitor neurotherapeutic responses that are relevant to common neurodegenerative disorders used to improve disease outcomes. PMID:27329163

  18. Appearance of the canine meninges in subtraction magnetic resonance images.

    PubMed

    Lamb, Christopher R; Lam, Richard; Keenihan, Erin K; Frean, Stephen

    2014-01-01

    The canine meninges are not visible as discrete structures in noncontrast magnetic resonance (MR) images, and are incompletely visualized in T1-weighted, postgadolinium images, reportedly appearing as short, thin curvilinear segments with minimal enhancement. Subtraction imaging facilitates detection of enhancement of tissues, hence may increase the conspicuity of meninges. The aim of the present study was to describe qualitatively the appearance of canine meninges in subtraction MR images obtained using a dynamic technique. Images were reviewed of 10 consecutive dogs that had dynamic pre- and postgadolinium T1W imaging of the brain that was interpreted as normal, and had normal cerebrospinal fluid. Image-anatomic correlation was facilitated by dissection and histologic examination of two canine cadavers. Meningeal enhancement was relatively inconspicuous in postgadolinium T1-weighted images, but was clearly visible in subtraction images of all dogs. Enhancement was visible as faint, small-rounded foci compatible with vessels seen end on within the sulci, a series of larger rounded foci compatible with vessels of variable caliber on the dorsal aspect of the cerebral cortex, and a continuous thin zone of moderate enhancement around the brain. Superimposition of color-encoded subtraction images on pregadolinium T1- and T2-weighted images facilitated localization of the origin of enhancement, which appeared to be predominantly dural, with relatively few leptomeningeal structures visible. Dynamic subtraction MR imaging should be considered for inclusion in clinical brain MR protocols because of the possibility that its use may increase sensitivity for lesions affecting the meninges. PMID:24833219

  19. Fundamental physics of magnetic resonance imaging.

    PubMed

    Villafana, T

    1988-07-01

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

  20. Magnetic resonance imaging in central pontine myelinolysis.

    PubMed Central

    Thompson, P D; Miller, D; Gledhill, R F; Rossor, M N

    1989-01-01

    Magnetic resonance imaging (MRI) was performed in two patients in whom a clinical diagnosis of central pontine myelinolysis (CPM) had been made. MRI showed lesions in the pons in both cases about 2 years after the illness, at a time when the spastic quadriparesis and pseudobulbar palsy had recovered. The persisting abnormal signals in CPM are likely to be due to fibrillary gliosis. Persistence of lesions on MRI means that the diagnosis of CPM may be electively, after the acute illness has resolved. Images PMID:2732743

  1. Multiparametric magnetic resonance imaging of prostate cancer.

    PubMed

    Hedgire, Sandeep S; Oei, Tamara N; McDermott, Shaunagh; Cao, Kai; Patel M, Zena; Harisinghani, Mukesh G

    2012-07-01

    In India, prostate cancer has an incidence rate of 3.9 per 100,000 men and is responsible for 9% of cancer-related mortality. It is the only malignancy that is diagnosed with an apparently blind technique, i.e., transrectal sextant biopsy. With increasing numbers of high-Tesla magnetic resonance imaging (MRI) equipment being installed in India, the radiologist needs to be cognizant about endorectal MRI and multiparametric imaging for prostate cancer. In this review article, we aim to highlight the utility of multiparamteric MRI in prostate cancer. It plays a crucial role, mainly in initial staging, restaging, and post-treatment follow-up. PMID:23599562

  2. 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

  3. Protease-specific nanosensors for magnetic resonance imaging.

    PubMed

    Schellenberger, Eyk; Rudloff, Franziska; Warmuth, Carsten; Taupitz, Matthias; Hamm, Bernd; Schnorr, Jörg

    2008-12-01

    Imaging of enzyme activity is a central goal of molecular imaging. With the introduction of fluorescent smart probes, optical imaging has become the modality of choice for experimental in vivo detection of enzyme activity. Here, we present a novel high-relaxivity nanosensor that is suitable for in vivo imaging of protease activity by magnetic resonance imaging. Upon specific protease cleavage, the nanoparticles rapidly switch from a stable low-relaxivity stealth state to become adhesive, aggregating high-relaxivity particles. To demonstrate the principle, we chose a cleavage motif of matrix metalloproteinase 9 (MMP-9), an enzyme important in inflammation, atherosclerosis, tumor progression, and many other diseases with alterations of the extracellular matrix. On the basis of clinically tested very small iron oxide particles (VSOP), the MMP-9-activatable protease-specific iron oxide particles (PSOP) have a hydrodynamic diameter of only 25 nm. PSOP are rapidly activated, resulting in aggregation and increased T2*-relaxivity. PMID:19007261

  4. In vivo nuclear magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Leblanc, A.

    1986-05-01

    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.

  5. Chest magnetic resonance imaging: a protocol suggestion*

    PubMed Central

    Hochhegger, Bruno; de Souza, Vinícius Valério Silveira; Marchiori, Edson; Irion, Klaus Loureiro; Souza Jr., Arthur Soares; Elias Junior, Jorge; Rodrigues, Rosana Souza; Barreto, Miriam Menna; Escuissato, Dante Luiz; Mançano, Alexandre Dias; Araujo Neto, César Augusto; Guimarães, Marcos Duarte; Nin, Carlos Schuler; Santos, Marcel Koenigkam; Silva, Jorge Luiz Pereira e

    2015-01-01

    In the recent years, with the development of ultrafast sequences, magnetic resonance imaging (MRI) has been established as a valuable diagnostic modality in body imaging. Because of improvements in speed and image quality, MRI is now ready for routine clinical use also in the study of pulmonary diseases. The main advantage of MRI of the lungs is its unique combination of morphological and functional assessment in a single imaging session. In this article, the authors review most technical aspects and suggest a protocol for performing chest MRI. The authors also describe the three major clinical indications for MRI of the lungs: staging of lung tumors; evaluation of pulmonary vascular diseases; and investigation of pulmonary abnormalities in patients who should not be exposed to radiation. PMID:26811555

  6. 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.

  7. 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

  8. Detecting light in whispering-gallery-mode resonators

    NASA Technical Reports Server (NTRS)

    Savchenkov, Anatoliy (Inventor); Maleki, Lutfollah (Inventor); Mohageg, Makan (Inventor); Le, Thanh M. (Inventor)

    2012-01-01

    An optical device including a whispering gallery mode (WGM) optical resonator configured to support one or more whispering gallery modes; and a photodetector optically coupled to an exterior surface of the optical resonator to receive evanescent light from the optical resonator to detect light inside the optical resonator.

  9. An Electromagnetic Resonance Circuit for Liquid Level Detection

    ERIC Educational Resources Information Center

    Hauge, B. L.; Helseth, L. E.

    2012-01-01

    Electromagnetic resonators are often used to detect foreign materials. Here we present a simple experiment for the measurement of liquid level. The resonator, consisting of a coil and a capacitor, is brought to resonance by an external magnetic field source, and the corresponding resonance frequency is determined using Fourier analysis combined…

  10. Multi-dimensionally encoded magnetic resonance imaging

    PubMed Central

    Lin, Fa-Hsuan

    2013-01-01

    Magnetic resonance imaging typically achieves spatial encoding by measuring the projection of a q-dimensional object over q-dimensional spatial bases created by linear spatial encoding magnetic fields (SEMs). Recently, imaging strategies using nonlinear SEMs have demonstrated potential advantages for reconstructing images with higher spatiotemporal resolution and reducing peripheral nerve stimulation. In practice, nonlinear SEMs and linear SEMs can be used jointly to further improve the image reconstruction performance. Here we propose the multi-dimensionally encoded (MDE) MRI to map a q-dimensional object onto a p-dimensional encoding space where p > q. MDE MRI is a theoretical framework linking imaging strategies using linear and nonlinear SEMs. Using a system of eight surface SEM coils with an eight-channel RF coil array, we demonstrate the five-dimensional MDE MRI for a two-dimensional object as a further generalization of PatLoc imaging and O-space imaging. We also present a method of optimizing spatial bases in MDE MRI. Results show that MDE MRI with a higher dimensional encoding space can reconstruct images more efficiently and with a smaller reconstruction error when the k-space sampling distribution and the number of samples are controlled. PMID:22926830

  11. Magnetic resonance imaging: present and future applications

    PubMed Central

    Johnston, Donald L.; Liu, Peter; Wismer, Gary L.; Rosen, Bruce R.; Stark, David D.; New, Paul F.J.; Okada, Robert D.; Brady, Thomas J.

    1985-01-01

    Magnetic resonance (MR) imaging has created considerable excitement in the medical community, largely because of its great potential to diagnose and characterize many different disease processes. However, it is becoming increasingly evident that, because MR imaging is similar to computed tomography (CT) scanning in identifying structural disorders and because it is more costly and difficult to use, this highly useful technique must be judged against CT before it can become an accepted investigative tool. At present MR imaging has demonstrated diagnostic superiority over CT in a limited number of important, mostly neurologic, disorders and is complementary to CT in the diagnosis of certain other disorders. For most of the remaining organ systems its usefulness is not clear, but the lack of ionizing radiation and MR's ability to produce images in any tomographic plane may eventually prove to be advantageous. The potential of MR imaging to display in-vivo spectra, multinuclear images and blood-flow data makes it an exciting investigative technique. At present, however, MR imaging units should be installed only in medical centres equipped with the clinical and basic research facilities that are essential to evaluate the ultimate role of this technique in the care of patients. ImagesFig. 5Fig. 6Fig. 7Fig. 8Fig. 9Fig. 10Fig. 11Fig. 12Fig. 13Fig. 14 PMID:3884120

  12. 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

  13. Compact electrically detected magnetic resonance setup

    SciTech Connect

    Eckardt, Michael Harneit, Wolfgang; Behrends, Jan; Münter, Detlef

    2015-04-15

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

  14. Compact electrically detected magnetic resonance setup

    NASA Astrophysics Data System (ADS)

    Eckardt, Michael; Behrends, Jan; Münter, Detlef; Harneit, Wolfgang

    2015-04-01

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

  15. Detection of lymph node metastases with ultrasmall superparamagnetic iron oxide (USPIO)-enhanced magnetic resonance imaging in oesophageal cancer: a feasibility study

    PubMed Central

    van der Jagt, E.J.; van Westreenen, H.L.; van Dullemen, H.M.; Kappert, P.; Groen, H.; Sietsma, J.; Oudkerk, M.; Plukker, J.Th.M.; van Dam, G.M.

    2009-01-01

    Abstract Aim: In this feasibility study we investigated whether magnetic resonance imaging (MRI) with ultrasmall superparamagnetic iron oxide (USPIO) can be used to identify regional and distant lymph nodes, including mediastinal and celiac lymph node metastases in patients with oesophageal cancer. Patients and methods: Ten patients with a potentially curative resectable cancer of the oesophagus were eligible for this study. All patients included in the study had positive lymph nodes on conventional staging (including endoscopic ultrasound, computed tomography and fluorodeoxyglucose-positron emission tomography). Nine patients underwent MRI + USPIO before surgery. Results were restricted to those patients who had both MRI + USPIO and histological examination. Results were compared with conventional staging and histopathologic findings. Results: One patient was excluded due to expired study time. Five out of 9 patients underwent an exploration; in 1 patient prior to surgery MRI + USPIO diagnosed liver metastases and in 3 patients an oesophageal resection was performed. USPIO uptake in mediastinal lymph nodes was seen in 6 out of 9 patients; in 3 patients non-malignant nodes were not visible. In total, 9 lymph node stations (of 6 patients) were separately analysed; 7 lymph node stations were assessed as positive (N1) on MRI+USPIO compared with 9 by conventional staging. According to histology findings, there was one false-positive and one false-negative result in MRI + USPIO. Also, conventional staging modalities had one false-positive and one false-negative result. MRI + USPIO had surplus value in one patient. Not all lymph node stations could be compared due to unforeseen explorations. No adverse effects occurred after USPIO infusion. Conclusion: MRI+USPIO identified the majority of mediastinal and celiac (suspect) lymph nodes in 9 patients with oesophageal cancer. MRI+USPIO could have an additional value in loco-regional staging; however, more

  16. Prototype explosives detection system based on nuclear resonance absorption in nitrogen

    SciTech Connect

    Morgado, R.E.; Arnone, G.; Cappiello, C.C.; Gardner, S.D.; Hollas, C.L.; Ussery, L.E.; White, J.M.; Zahrt, J.D.; Krauss, R.A.

    1993-12-01

    A-prototype explosives detection system that was developed for experimental evaluation of a nuclear resonance absorption techniques is described. The major subsystems are a proton accelerator and beam transport, high-temperature proton target, an airline-luggage tomographic inspection station, and an image-processing/detection- alarm subsystem. The detection system performance, based on a limited experimental test, is reported.

  17. Prototype explosives-detection system based on nuclear-resonance absorption in nitrogen

    SciTech Connect

    Morgado, R.E.; Arnone, G.; Cappiello, C.C.; Gardner, S.D.; Hollas, C.L.; Ussery, L.E.; White, J.M.; Zahrt, J.D.; Krauss, R.A.

    1994-06-01

    A prototype explosives-detection system (EDS) that was developed for experimental evaluation of a nuclear-resonance absorption technique is described. The major subsystems are a proton accelerator and beam transport, high-temperature proton target, an airline-luggage tomographic inspection station, and an image-processing/detection-alarm subsystem. The detection system performance, based on a limited experimental test, is reported.

  18. Molecular imaging using a targeted magnetic resonance hyperpolarized biosensor.

    PubMed

    Schröder, Leif; Lowery, Thomas J; Hilty, Christian; Wemmer, David E; Pines, Alexander

    2006-10-20

    A magnetic resonance approach is presented that enables high-sensitivity, high-contrast molecular imaging by exploiting xenon biosensors. These sensors link xenon atoms to specific biomolecular targets, coupling the high sensitivity of hyperpolarized nuclei with the specificity of biochemical interactions. We demonstrated spatial resolution of a specific target protein in vitro at micromolar concentration, with a readout scheme that reduces the required acquisition time by >3300-fold relative to direct detection. This technique uses the signal of free hyperpolarized xenon to dramatically amplify the sensor signal via chemical exchange saturation transfer (CEST). Because it is approximately 10,000 times more sensitive than previous CEST methods and other molecular magnetic resonance imaging techniques, it marks a critical step toward the application of xenon biosensors as selective contrast agents in biomedical applications. PMID:17053143

  19. Cardiovascular magnetic resonance imaging-based computational fluid dynamics/fluid-structure interaction pilot study to detect early vascular changes in pediatric patients with type 1 diabetes.

    PubMed

    Samyn, Margaret M; Dholakia, Ronak; Wang, Hongfeng; Co-Vu, Jennifer; Yan, Ke; Widlansky, Michael E; LaDisa, John F; Simpson, Pippa; Alemzadeh, Ramin

    2015-04-01

    We hypothesized that pediatric patients with type 1 diabetes have cardiac magnetic resonance (CMR) detectable differences in thoracic aortic wall properties and hemodynamics leading to significant local differences in indices of wall shear stress, when compared with age-matched control subjects without diabetes. Pediatric patients with type 1 diabetes were recruited from Children's Hospital of Wisconsin and compared with controls. All underwent morning CMR scanning, 4-limb blood pressure, brachial artery reactivity testing, and venipuncture. Patient-specific computational fluid dynamics modeling with fluid-structure interaction, based on CMR data, determined regional time-averaged wall shear stress (TAWSS) and oscillatory shear index (OSI). Twenty type 1 diabetic subjects, median age 15.8 years (11.6-18.4) and 8 controls 15.4 years (10.3-18.2) were similar except for higher glucose, hemoglobin A1c, and triglycerides for type 1 diabetic subjects. Lower flow-mediated dilation was seen for those with type 1 diabetes (6.5) versus controls (7.8), p = 0.036. For type 1 diabetic subjects, the aorta had more regions with high TAWSS when compared to controls. OSI maps appeared similar. Flow-mediated dilation positively correlated with age at diabetes diagnosis (r = 0.468, p = 0.038) and hemoglobin A1c (r = 0.472, p = 0.036), but did not correlate with aortic distensibility, TAWSS, or OSI. TAWSS did not correlate with any clinical parameter for either group. CMR shows regional differences in aortic wall properties for young diabetic patients. Some local differences in wall shear stress indices were also observed, but a longitudinal study is now warranted. PMID:25577225

  20. Simultaneous in vivo positron emission tomography and magnetic resonance imaging.

    PubMed

    Catana, Ciprian; Procissi, Daniel; Wu, Yibao; Judenhofer, Martin S; Qi, Jinyi; Pichler, Bernd J; Jacobs, Russell E; Cherry, Simon R

    2008-03-11

    Positron emission tomography (PET) and magnetic resonance imaging (MRI) are widely used in vivo imaging technologies with both clinical and biomedical research applications. The strengths of MRI include high-resolution, high-contrast morphologic imaging of soft tissues; the ability to image physiologic parameters such as diffusion and changes in oxygenation level resulting from neuronal stimulation; and the measurement of metabolites using chemical shift imaging. PET images the distribution of biologically targeted radiotracers with high sensitivity, but images generally lack anatomic context and are of lower spatial resolution. Integration of these technologies permits the acquisition of temporally correlated data showing the distribution of PET radiotracers and MRI contrast agents or MR-detectable metabolites, with registration to the underlying anatomy. An MRI-compatible PET scanner has been built for biomedical research applications that allows data from both modalities to be acquired simultaneously. Experiments demonstrate no effect of the MRI system on the spatial resolution of the PET system and <10% reduction in the fraction of radioactive decay events detected by the PET scanner inside the MRI. The signal-to-noise ratio and uniformity of the MR images, with the exception of one particular pulse sequence, were little affected by the presence of the PET scanner. In vivo simultaneous PET and MRI studies were performed in mice. Proof-of-principle in vivo MR spectroscopy and functional MRI experiments were also demonstrated with the combined scanner. PMID:18319342

  1. Simultaneous in vivo positron emission tomography and magnetic resonance imaging

    PubMed Central

    Catana, Ciprian; Procissi, Daniel; Wu, Yibao; Judenhofer, Martin S.; Qi, Jinyi; Pichler, Bernd J.; Jacobs, Russell E.; Cherry, Simon R.

    2008-01-01

    Positron emission tomography (PET) and magnetic resonance imaging (MRI) are widely used in vivo imaging technologies with both clinical and biomedical research applications. The strengths of MRI include high-resolution, high-contrast morphologic imaging of soft tissues; the ability to image physiologic parameters such as diffusion and changes in oxygenation level resulting from neuronal stimulation; and the measurement of metabolites using chemical shift imaging. PET images the distribution of biologically targeted radiotracers with high sensitivity, but images generally lack anatomic context and are of lower spatial resolution. Integration of these technologies permits the acquisition of temporally correlated data showing the distribution of PET radiotracers and MRI contrast agents or MR-detectable metabolites, with registration to the underlying anatomy. An MRI-compatible PET scanner has been built for biomedical research applications that allows data from both modalities to be acquired simultaneously. Experiments demonstrate no effect of the MRI system on the spatial resolution of the PET system and <10% reduction in the fraction of radioactive decay events detected by the PET scanner inside the MRI. The signal-to-noise ratio and uniformity of the MR images, with the exception of one particular pulse sequence, were little affected by the presence of the PET scanner. In vivo simultaneous PET and MRI studies were performed in mice. Proof-of-principle in vivo MR spectroscopy and functional MRI experiments were also demonstrated with the combined scanner. PMID:18319342

  2. Metabolite specific proton magnetic resonance imaging

    SciTech Connect

    Hurd, R.E.; Freeman, D.M.

    1989-06-01

    An imaging method is described that makes use of proton double quantum nuclear magnetic resonance (NMR) to construct images based on selected metabolites such as lactic acid. The optimization of the method is illustrated in vitro, followed by in vivo determination of lactic acid distribution in a solid tumor model. Water suppression and editing of lipid signals are such that two-dimensional spectra of lactic acid may be obtained from a radiation-induced fibrosarcoma (RIF-1) tumor in under 1 min and lactic acid images from the same tumor in under 1 hr at 2.0 T. This technique provides a fast and reproducible method at moderate magnetic field strength for mapping biologically relevant metabolites.

  3. Magnetic resonance imaging in Leber's optic neuropathy.

    PubMed Central

    Kermode, A G; Moseley, I F; Kendall, B E; Miller, D H; MacManus, D G; McDonald, W I

    1989-01-01

    Thirteen males with Leber's optic neuropathy had magnetic resonance imaging (MRI) of the brain, and in eight the optic nerves were imaged using STIR (Short Time Inversion Recovery) sequences. All optic nerve scans were abnormal. In seven with bilateral visual loss four showed bilateral increased optic nerve signal and three unilateral increase. The involvement was of the mid and posterior intra-orbital sections over three 5 mm slices or more with sparing of the anterior portion. One patient with unilateral visual loss had increased signal only on the affected side. Brain MRI was normal, in marked contrast to the findings in clinically isolated optic neuritis in which multiple white matter lesions are seen in the majority. Images PMID:2732742

  4. Ultrafast Imaging using Spectral Resonance Modulation

    NASA Astrophysics Data System (ADS)

    Huang, Eric; Ma, Qian; Liu, Zhaowei

    2016-04-01

    CCD cameras are ubiquitous in research labs, industry, and hospitals for a huge variety of applications, but there are many dynamic processes in nature that unfold too quickly to be captured. Although tradeoffs can be made between exposure time, sensitivity, and area of interest, ultimately the speed limit of a CCD camera is constrained by the electronic readout rate of the sensors. One potential way to improve the imaging speed is with compressive sensing (CS), a technique that allows for a reduction in the number of measurements needed to record an image. However, most CS imaging methods require spatial light modulators (SLMs), which are subject to mechanical speed limitations. Here, we demonstrate an etalon array based SLM without any moving elements that is unconstrained by either mechanical or electronic speed limitations. This novel spectral resonance modulator (SRM) shows great potential in an ultrafast compressive single pixel camera.

  5. Ultrafast Imaging using Spectral Resonance Modulation.

    PubMed

    Huang, Eric; Ma, Qian; Liu, Zhaowei

    2016-01-01

    CCD cameras are ubiquitous in research labs, industry, and hospitals for a huge variety of applications, but there are many dynamic processes in nature that unfold too quickly to be captured. Although tradeoffs can be made between exposure time, sensitivity, and area of interest, ultimately the speed limit of a CCD camera is constrained by the electronic readout rate of the sensors. One potential way to improve the imaging speed is with compressive sensing (CS), a technique that allows for a reduction in the number of measurements needed to record an image. However, most CS imaging methods require spatial light modulators (SLMs), which are subject to mechanical speed limitations. Here, we demonstrate an etalon array based SLM without any moving elements that is unconstrained by either mechanical or electronic speed limitations. This novel spectral resonance modulator (SRM) shows great potential in an ultrafast compressive single pixel camera. PMID:27122101

  6. Magnetic resonance imaging of optic nerve

    PubMed Central

    Gala, Foram

    2015-01-01

    Optic nerves are the second pair of cranial nerves and are unique as they represent an extension of the central nervous system. Apart from clinical and ophthalmoscopic evaluation, imaging, especially magnetic resonance imaging (MRI), plays an important role in the complete evaluation of optic nerve and the entire visual pathway. In this pictorial essay, the authors describe segmental anatomy of the optic nerve and review the imaging findings of various conditions affecting the optic nerves. MRI allows excellent depiction of the intricate anatomy of optic nerves due to its excellent soft tissue contrast without exposure to ionizing radiation, better delineation of the entire visual pathway, and accurate evaluation of associated intracranial pathologies. PMID:26752822

  7. Ultrafast Imaging using Spectral Resonance Modulation

    PubMed Central

    Huang, Eric; Ma, Qian; Liu, Zhaowei

    2016-01-01

    CCD cameras are ubiquitous in research labs, industry, and hospitals for a huge variety of applications, but there are many dynamic processes in nature that unfold too quickly to be captured. Although tradeoffs can be made between exposure time, sensitivity, and area of interest, ultimately the speed limit of a CCD camera is constrained by the electronic readout rate of the sensors. One potential way to improve the imaging speed is with compressive sensing (CS), a technique that allows for a reduction in the number of measurements needed to record an image. However, most CS imaging methods require spatial light modulators (SLMs), which are subject to mechanical speed limitations. Here, we demonstrate an etalon array based SLM without any moving elements that is unconstrained by either mechanical or electronic speed limitations. This novel spectral resonance modulator (SRM) shows great potential in an ultrafast compressive single pixel camera. PMID:27122101

  8. The magnetic resonance imaging-linac system.

    PubMed

    Lagendijk, Jan J W; Raaymakers, Bas W; van Vulpen, Marco

    2014-07-01

    The current image-guided radiotherapy systems are suboptimal in the esophagus, pancreas, kidney, rectum, lymph node, etc. These locations in the body are not easily accessible for fiducials and cannot be visualized sufficiently on cone-beam computed tomographies, making daily patient set-up prone to geometrical uncertainties and hinder dose optimization. Additional interfraction and intrafraction uncertainties for those locations arise from motion with breathing and organ filling. To allow real-time imaging of all patient tumor locations at the actual treatment position a fully integrated 1.5-T, diagnostic quality, magnetic resonance imaging with a 6-MV linear accelerator is presented. This system must enable detailed dose painting at all body locations. PMID:24931095

  9. Nuclear magnetic resonance imaging in medicine

    PubMed Central

    McKinstry, C S

    1986-01-01

    Using the technique of nuclear magnetic resonance (NMR, MR, MRI), the first images displaying pathology in humans were published in 1980.1 Since then, there has been a rapid extension in the use of the technique, with an estimated 225 machines in use in the USA at the end of 1985.2 Considerable enthusiasm has been expressed for this new imaging technique,3 although awareness of its high cost in the present economic climate has led to reservations being expressed in other quarters.2 The aim of this article is to give an outline of the present state of NMR, and indicate some possible future developments. ImagesFig 1Fig 2Fig 3(a)Fig 3 (b)Fig 4Fig 5Fig 6Fig 7 (a)Fig 7 (b)Fig 8Fig 9Fig 10 PMID:3811023

  10. Stem cell labeling for magnetic resonance imaging.

    PubMed

    Himmelreich, Uwe; Hoehn, Mathias

    2008-01-01

    In vivo applications of cells for the monitoring of their cell dynamics increasingly use non-invasive magnetic resonance imaging. This imaging modality allows in particular to follow the migrational activity of stem cells intended for cell therapy strategies. All these approaches require the prior labeling of the cells under investigation for excellent contrast against the host tissue background in the imaging modality. The present review discusses the various routes of cell labeling and describes the potential to observe both cell localization and their cell-specific function in vivo. Possibilities for labeling strategies, pros and cons of various contrast agents are pointed out while potential ambiguities or problems of labeling strategies are emphasized. PMID:18465447

  11. Superconducting Magnets for Magnetic Resonance Imaging

    NASA Astrophysics Data System (ADS)

    Feenan, Peter

    2000-03-01

    MRI is now a well established diagnostic technique in medicine. The richness of information provided by magnetic resonance gives rise to a variety of techniques which in turn leads to a variety of magnet designs. Magnet designers must consider suitable superconduting materials for the magnet, but need also to consider the overall fomat of the magnet to maximise patient comfort, access for clinicians and convenience of use - in some examples magnets are destined for use within the operating theatre and special considerations are required for this. Magnet types include; (1) low-field general purpose imagers, (2) extremity imaging, (3) open magnets with exellent all-round access often employing iron or permanent magnetic materials, (4) high-field magnets, and (5) very high-field (7 Tesla and more) magnets for spectroscopy and functional imaging research. Examples of these magnet varieties will be shown and some of the design challenges discussed.

  12. Hemorrhage detection in MRI brain images using images features

    NASA Astrophysics Data System (ADS)

    Moraru, Luminita; Moldovanu, Simona; Bibicu, Dorin; Stratulat (Visan), Mirela

    2013-11-01

    The abnormalities appear frequently on Magnetic Resonance Images (MRI) of brain in elderly patients presenting either stroke or cognitive impairment. Detection of brain hemorrhage lesions in MRI is an important but very time-consuming task. This research aims to develop a method to extract brain tissue features from T2-weighted MR images of the brain using a selection of the most valuable texture features in order to discriminate between normal and affected areas of the brain. Due to textural similarity between normal and affected areas in brain MR images these operation are very challenging. A trauma may cause microstructural changes, which are not necessarily perceptible by visual inspection, but they could be detected by using a texture analysis. The proposed analysis is developed in five steps: i) in the pre-processing step: the de-noising operation is performed using the Daubechies wavelets; ii) the original images were transformed in image features using the first order descriptors; iii) the regions of interest (ROIs) were cropped from images feature following up the axial symmetry properties with respect to the mid - sagittal plan; iv) the variation in the measurement of features was quantified using the two descriptors of the co-occurrence matrix, namely energy and homogeneity; v) finally, the meaningful of the image features is analyzed by using the t-test method. P-value has been applied to the pair of features in order to measure they efficacy.

  13. Radiation necrosis of the optic chiasm, optic tract, hypothalamus, and upper pons after radiotherapy for pituitary adenoma, detected by gadolinium-enhanced, T1-weighted magnetic resonance imaging: Case report

    SciTech Connect

    Tachibana, O.; Yamaguchi, N.; Yamashima, T.; Yamashita, J. )

    1990-10-01

    A 26-year-old woman was treated for a prolactin secreting pituitary adenoma by surgery and radiotherapy (5860 rads). Fourteen months later, she developed right hemiparesis and dysarthria. A T1-weighted magnetic resonance imaging scan using gadolinium contrast showed a small, enhanced lesion in the upper pons. Seven months later, she had a sudden onset of loss of vision, and radiation optic neuropathy was diagnosed. A T1-weighted magnetic resonance imaging scan showed widespread gadolinium-enhanced lesions in the optic chiasm, optic tract, and hypothalamus. Magnetic resonance imaging is indispensable for the early diagnosis of radiation necrosis, which is not visualized by radiography or computed tomography.

  14. Global Doppler frequency shift detection with near-resonant interferometry

    NASA Astrophysics Data System (ADS)

    Landolt, Andrin; Roesgen, Thomas

    2009-10-01

    The recent development in measuring 2D Doppler shift distributions for flow velocimetry using the dispersive properties of atomic line filters is presented. On the basis of velocity field measurements on a subsonic jet flow and a tip vortex flow in a medium-sized wind tunnel, the technique was assessed. Atomic line filters near a resonant transition combine imaging capabilities with a sharp frequency cutoff and an associated region of strong anomalous dispersion. While conventional Doppler global velocimetry relies on the absorption of the filter to convert frequency shifts to intensity variations, near-resonant interferometry uses its dispersion to detect frequency shifts as phase changes in an interference pattern. In the present setup, an iodine vapor cell in an imaging Michelson interferometer is used. With the illuminating laser frequency tuned near a resonant transition, the cell’s dispersion converts the frequency content of the field of view into a distortion of the carrier-fringe pattern recorded at the image plane of the interferometer. The phase distribution in the fringe images is reconstructed by filtering the individual images with a 2D Gabor filter pair tuned to the spatial frequencies of the basic carrier-fringe pattern. The post-processing is concluded with subsequent phase-unwrapping and subtraction of the carrier reference fringe phase. The method and the setup were demonstrated and calibrated experimentally on a rotating disc. The capability of the technique to operate in a real experimental environment was validated in a free subsonic jet and a tip vortex flow behind a wing section in a medium-sized wind tunnel facility. The measurements were found to be in generally good agreement with the theoretically predicted system characteristics and the reference measurements. As with other Doppler global techniques, the stability of the pulsed laser system and the secondary scattering in the test volume were identified as the main error sources.

  15. [Indications for magnetic resonance imaging in pneumology].

    PubMed

    Arrivé, L

    1997-04-19

    Tissue mobilization caused by respiration and heart beat and lower spacial resolution than with computed tomography has limited use of magnetic resonance imaging (MRI) in pneumology. Nevertheless, because of the high-quality of spontaneous contrast and the non irradiation nature of the examination, there are selected indications. For bronchogenic cancer, MRI is reserved for selected cases to evaluate tumor extension. For tumors of the mediastinum, MRI is particularly useful for evaluating extension of neurogenic tumors. MRI also gives a better visualization of processes involving the diaphragm than computed tomography. The development of magnetic resonance angiography is a major progress for exploration of pulmonary embolism as repeated acquisitions can be obtained without injection of a contrast medium. Several studies have shown that MRI visualizes well solitary lung nodules, clearly distinguishing fat content from vascularized nodules. For the pulmonary parenchyma, further advances are necessary before MRI can become a routine exploration technique. PMID:9180867

  16. 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.

  17. Magnetic Resonance Imaging at Ultrahigh Fields

    PubMed Central

    Uğurbil, Kamil

    2014-01-01

    Since the introduction of 4 T human systems in three academic laboratories circa 1990, rapid progress in imaging and spectroscopy studies in humans at 4 T and animal model systems at 9.4 T have led to the introduction of 7 T and higher magnetic fields for human investigation at about the turn of the century. Work conducted on these platforms has demonstrated the existence of significant advantages in SNR and biological information content at these ultrahigh fields, as well as the presence of numerous challenges. Primary difference from lower fields is the deviation from the near field regime; at the frequencies corresponding to hydrogen resonance conditions at ultrahigh fields, the RF is characterized by attenuated traveling waves in the human body, which leads to image nonuniformities for a given sample-coil configuration because of interferences. These nonuniformities were considered detrimental to the progress of imaging at high field strengths. However, they are advantageous for parallel imaging for signal reception and parallel transmission, two critical technologies that account, to a large extend, for the success of ultrahigh fields. With these technologies, and improvements in instrumentation and imaging methods, ultra-high fields have provided unprecedented gains in imaging of brain function and anatomy, and started to make inroads into investigation of the human torso and extremities. As extensive as they are, these gains still constitute a prelude to what is to come given the increasingly larger effort committed to ultrahigh field research and development of ever better instrumentation and techniques. PMID:24686229

  18. Orthogonal resonators for pulse in vivo electron paramagnetic imaging at 250 MHz

    PubMed Central

    Sundramoorthy, Subramanian V.; Epel, Boris; Halpern, Howard J.

    2014-01-01

    A 250 MHz bimodal resonator with a 19 mm internal diameter for in vivo pulse electron paramagnetic resonance (EPR) imaging is presented. Two separate coaxial cylindrical resonators inserted one into another were used for excitation and detection. The Alderman-Grant excitation resonator (AGR) showed the highest efficiency among all the excitation resonators tested. The magnetic field of AGR is confined to the volume of the detection resonator, which results in highly efficient use of the radio frequency power. A slotted inner single loop single gap resonator (SLSG LGR), coaxial to the AGR, was used for signal detection. The resulting bimodal resonator (AG/LGR) has two mutually orthogonal magnetic field modes; one of them has the magnetic field in the axial direction. The resonator built in our laboratory achieved 40dB isolation over 20 MHz bandwidth with quality factors of detection and excitation resonators of 36 and 11 respectively. Considerable improvement of the B1 homogeneity and EPR image quality in comparison with reflection loop-gap resonator of similar size and volume was observed. PMID:24530507

  19. Magnetic resonance imaging of spinal injury.

    PubMed

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

    1989-03-01

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

  20. Saliency detection for stereoscopic images.

    PubMed

    Fang, Yuming; Wang, Junle; Narwaria, Manish; Le Callet, Patrick; Lin, Weisi

    2014-06-01

    Many saliency detection models for 2D images have been proposed for various multimedia processing applications during the past decades. Currently, the emerging applications of stereoscopic display require new saliency detection models for salient region extraction. Different from saliency detection for 2D images, the depth feature has to be taken into account in saliency detection for stereoscopic images. In this paper, we propose a novel stereoscopic saliency detection framework based on the feature contrast of color, luminance, texture, and depth. Four types of features, namely color, luminance, texture, and depth, are extracted from discrete cosine transform coefficients for feature contrast calculation. A Gaussian model of the spatial distance between image patches is adopted for consideration of local and global contrast calculation. Then, a new fusion method is designed to combine the feature maps to obtain the final saliency map for stereoscopic images. In addition, we adopt the center bias factor and human visual acuity, the important characteristics of the human visual system, to enhance the final saliency map for stereoscopic images. Experimental results on eye tracking databases show the superior performance of the proposed model over other existing methods. PMID:24832595

  1. Crack detection using resonant ultrasound spectroscopy

    DOEpatents

    Migliori, Albert; Bell, Thomas M.; Rhodes, George W.

    1994-01-01

    Method and apparatus are provided for detecting crack-like flaws in components. A plurality of exciting frequencies are generated and applied to a component in a dry condition to obtain a first ultrasonic spectrum of the component. The component is then wet with a selected liquid to penetrate any crack-like flaws in the component. The plurality of exciting frequencies are again applied to the component and a second ultrasonic spectrum of the component is obtained. The wet and dry ultrasonic spectra are then analyzed to determine the second harmonic components in each of the ultrasonic resonance spectra and the second harmonic components are compared to ascertain the presence of crack-like flaws in the component.

  2. Crack detection using resonant ultrasound spectroscopy

    DOEpatents

    Migliori, A.; Bell, T.M.; Rhodes, G.W.

    1994-10-04

    Method and apparatus are provided for detecting crack-like flaws in components. A plurality of exciting frequencies are generated and applied to a component in a dry condition to obtain a first ultrasonic spectrum of the component. The component is then wet with a selected liquid to penetrate any crack-like flaws in the component. The plurality of exciting frequencies are again applied to the component and a second ultrasonic spectrum of the component is obtained. The wet and dry ultrasonic spectra are then analyzed to determine the second harmonic components in each of the ultrasonic resonance spectra and the second harmonic components are compared to ascertain the presence of crack-like flaws in the component. 5 figs.

  3. Explosives detection by nuclear quadrupole resonance (NQR)

    NASA Astrophysics Data System (ADS)

    Garroway, Allen N.; Buess, Michael L.; Yesinowski, James P.; Miller, Joel B.; Krauss, Ronald A.

    1994-10-01

    Pure nuclear quadrupole resonance (NQR) of 14N nuclei is quite promising as a method for detecting explosives such as RDX and contraband narcotics such as cocaine and heroin in quantities of interest. Pure NQR is conducted without an external applied magnetic field, so potential concerns about damage to magnetically encoded data or exposure of personnel to large magnetic fields are not relevant. Because NQR frequencies of different compounds are quite distinct, we do not encounter false alarms from the NQR signals of other benign materials. We have constructed a laboratory prototype NQR explosives detector which interrogates a volume of 300 liters (10 ft3). This paper presents abbreviated results from a demonstration of the laboratory prototype NQR explosives detector conducted at the Federal Aviation Administration Technical Center in May 1994 on RDX-based explosives.

  4. Magnetic resonance imaging findings of intramammary metastases.

    PubMed

    Wienbeck, Susanne; Herzog, Aimee; Kinner, Sonja; Surov, Alexey

    2016-01-01

    The purpose of this study was to identify magnetic resonance imaging (MRI) findings of intramammary metastases (IM). We identified 8 cases with IM, which were investigated by breast MRI (1.5T). In every case, the diagnosis of IM was proven histopathologically on breast biopsy specimens. Overall, 187 IM were identified. IM had inconsistent MRI features, which cannot be clearly classify as benign or malignant. IM should be taken into consideration in the differential diagnosis of breast lesions to avoid possible misinterpretations. PMID:27133668

  5. Developments in boron magnetic resonance imaging (MRI)

    SciTech Connect

    Schweizer, M.

    1995-11-01

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

  6. Various diffusion magnetic resonance imaging techniques for pancreatic cancer

    PubMed Central

    Tang, Meng-Yue; Zhang, Xiao-Ming; Chen, Tian-Wu; Huang, Xiao-Hua

    2015-01-01

    Pancreatic cancer is one of the most common malignant tumors and remains a treatment-refractory cancer with a poor prognosis. Currently, the diagnosis of pancreatic neoplasm depends mainly on imaging and which methods are conducive to detecting small lesions. Compared to the other techniques, magnetic resonance imaging (MRI) has irreplaceable advantages and can provide valuable information unattainable with other noninvasive or minimally invasive imaging techniques. Advances in MR hardware and pulse sequence design have particularly improved the quality and robustness of MRI of the pancreas. Diffusion MR imaging serves as one of the common functional MRI techniques and is the only technique that can be used to reflect the diffusion movement of water molecules in vivo. It is generally known that diffusion properties depend on the characterization of intrinsic features of tissue microdynamics and microstructure. With the improvement of the diffusion models, diffusion MR imaging techniques are increasingly varied, from the simplest and most commonly used technique to the more complex. In this review, the various diffusion MRI techniques for pancreatic cancer are discussed, including conventional diffusion weighted imaging (DWI), multi-b DWI based on intra-voxel incoherent motion theory, diffusion tensor imaging and diffusion kurtosis imaging. The principles, main parameters, advantages and limitations of these techniques, as well as future directions for pancreatic diffusion imaging are also discussed. PMID:26753059

  7. 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

  8. A Metric for Reducing False Positives in the Computer-Aided Detection of Breast Cancer from Dynamic Contrast-Enhanced Magnetic Resonance Imaging Based Screening Examinations of High-Risk Women.

    PubMed

    Levman, Jacob E D; Gallego-Ortiz, Cristina; Warner, Ellen; Causer, Petrina; Martel, Anne L

    2016-02-01

    Magnetic resonance imaging (MRI)-enabled cancer screening has been shown to be a highly sensitive method for the early detection of breast cancer. Computer-aided detection systems have the potential to improve the screening process by standardizing radiologists to a high level of diagnostic accuracy. This retrospective study was approved by the institutional review board of Sunnybrook Health Sciences Centre. This study compares the performance of a proposed method for computer-aided detection (based on the second-order spatial derivative of the relative signal intensity) with the signal enhancement ratio (SER) on MRI-based breast screening examinations. Comparison is performed using receiver operating characteristic (ROC) curve analysis as well as free-response receiver operating characteristic (FROC) curve analysis. A modified computer-aided detection system combining the proposed approach with the SER method is also presented. The proposed method provides improvements in the rates of false positive markings over the SER method in the detection of breast cancer (as assessed by FROC analysis). The modified computer-aided detection system that incorporates both the proposed method and the SER method yields ROC results equal to that produced by SER while simultaneously providing improvements over the SER method in terms of false positives per noncancerous exam. The proposed method for identifying malignancies outperforms the SER method in terms of false positives on a challenging dataset containing many small lesions and may play a useful role in breast cancer screening by MRI as part of a computer-aided detection system. PMID:26293705

  9. 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.

  10. Nuclear magnetic resonance imaging of the spine

    SciTech Connect

    Modic, M.T.; Weinstein, M.A.; Pavlicek, W.; Starnes, D.L.; Duchesneau, P.M.; Boumphrey, F.; Hardy, R.J. Jr.

    1984-01-01

    Forty subjects were examined to determine the accuracy and clinical usefulness of nuclear magnetic resonance (NMR) examination of the spine. The NMR images were compared with plain radiographs, high-resolution computed tomograms, and myelograms. The study included 15 patients with normal spinal cord anatomy and 25 patients whose pathological conditions included canal stenosis, herniated discs, metastatic tumors, primary cord tumor, trauma, Chiari malformations, syringomyelia, and developmental disorders. Saturation recovery images were best in differentiating between soft tissue and cerebrospinal fluid. NMR was excellent for the evaluation of the foramen magnum region and is presently the modality of choice for the diagnosis of syringomyelia and Chiari malformation. NMR was accurate in diagnosing spinal cord trauma and spinal canal block.

  11. 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.

  12. Imaging diagnosis-magnetic resonance imaging findings of an intracranial epidural tuberculoma in a dog.

    PubMed

    de la Fuente, Cristian; Pumarola, Martí; Ródenas, Sergio; Foradada, Laia; Lloret, Albert; Pérez de Val, Bernat; Añor, Sònia

    2012-01-01

    Magnetic resonance (MR) imaging is highly sensitive for detecting tuberculomas in human patients but the specificity of the MR imaging features is low. Misdiagnosis with intracranial neoplasia is common, especially with dural-based lesions or lesions located in the epidural space. We describe the MR imaging characteristics of an intracranial epidural tuberculoma caused by Mycobacterium tuberculosis infection in a dog. The intracranial mass and skull flat bone lysis and erosion are similar to those described in human caseating tuberculomas and can mimic intracranial neoplastic disease. PMID:22702644

  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. PLANTAR THROMBOPHLEBITIS: MAGNETIC RESONANCE IMAGING FINDINGS

    PubMed Central

    Miranda, Frederico Celestino; Carneiro, Renato Duarte; Longo, Carlos Henrique; Fernandes, Túlio Diniz; Rosemberg, Laércio Alberto; de Gusmão Funari, Marcelo Buarque

    2015-01-01

    Objective: Demonstrate the magnetic resonance imaging (MRI) findings in plantar thrombophlebitis. Methods: Retrospective review of twenty patients with pain in the plantar region of the foot, in which the MRI findings indicated plantar thrombophlebitis. Results: A total of fourteen men and six women, mean age 46.7 years were evaluated. Eight of these patients also underwent Doppler ultrasonography, which confirmed the thrombophlebitis. The magnetic resonance images were evaluated in consensus by two radiologists with experience in musculoskeletal radiology (more than 10 years each), showing perivascular edema in all twenty patients (100%) and muscle edema in nineteen of the twenty patients (95%). All twenty patients had intraluminal intermediate signal intensity on T2-weighted (100%) and venous ectasia was present in seventeen of the twenty cases (85%). Collateral veins were visualized in one of the twenty patients (5%). All fourteen cases (100%), in which intravenous contrast was administered, showed perivenular tissues enhancement and intraluminal filling defect. Venous ectasia, loss of compressibility and no flow on Doppler ultrasound were also observed in all eight cases examined by the method. Conclusion: MRI is a sensitive in the evaluation of plant thrombophlebitis in patients with plantar foot pain. PMID:27047898

  15. Magnetic resonance imaging in pediatric pulmonary hypertension.

    PubMed

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

    2015-06-01

    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

  16. Optic Nerve Assessment Using 7-Tesla Magnetic Resonance Imaging

    PubMed Central

    Singh, Arun D.; Platt, Sean M.; Lystad, Lisa; Lowe, Mark; Oh, Sehong; Jones, Stephen E.; Alzahrani, Yahya; Plesec, Thomas

    2016-01-01

    Purpose The purpose of this study was to correlate high-resolution magnetic resonance imaging (MRI) and histologic findings in a case of juxtapapillary choroidal melanoma with clinical evidence of optic nerve invasion. Methods With institutional review board approval, an enucleated globe with choroidal melanoma and optic nerve invasion was imaged using a 7-tesla MRI followed by histopathologic evaluation. Results Optical coherence tomography, B-scan ultrasonography, and 1.5-tesla MRI of the orbit (1-mm sections) could not detect optic disc invasion. Ex vivo, 7-tesla MRI detected optic nerve invasion, which correlated with histopathologic features. Conclusions Our case demonstrates the potential to document the existence of optic nerve invasion in the presence of an intraocular tumor, a feature that has a major bearing on decision making, particularly for consideration of enucleation. PMID:27239461

  17. Metabolomic Imaging for Human Prostate Cancer Detection

    PubMed Central

    Wu, Chin-Lee; Jordan, Kate W.; Ratai, Eva M.; Sheng, Jinhua; Adkins, Christen B.; DeFeo, Elita M; Jenkins, Bruce G.; Ying, Leslie; McDougal, W. Scott; Cheng, Leo L.

    2010-01-01

    As current radiological approaches cannot accurately localize prostate cancer in vivo, biopsies are conducted at random within prostates for at-risk patients, leading to high false-negative rates. Metabolomic imaging can map cancer-specific biomolecular profile values onto anatomical structures to direct biopsy. In this preliminary study, we evaluated five prostatectomy-removed whole prostates from biopsy-proven cancer patients on a 7 Tesla human, whole-body magnetic resonance scanner. Localized, multi-cross-sectional, multi-voxel magnetic resonance spectra were used to construct a malignancy index based on prostate cancer metabolomic profiles obtained from previous, intact tissue analyses by a 14 Tesla spectrometer. This calculated Malignancy Index shows linear correlation with lesion size (p<0.013) and demonstrates a 93–97% overall accuracy for detecting the presence of prostate cancer lesions. PMID:20371475

  18. 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

  19. Focal liver lesions: Practical magnetic resonance imaging approach.

    PubMed

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

    2015-08-01

    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

  20. Image fusion for dynamic contrast enhanced magnetic resonance imaging

    PubMed Central

    Twellmann, Thorsten; Saalbach, Axel; Gerstung, Olaf; Leach, Martin O; Nattkemper, Tim W

    2004-01-01

    Background Multivariate imaging techniques such as dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) have been shown to provide valuable information for medical diagnosis. Even though these techniques provide new information, integrating and evaluating the much wider range of information is a challenging task for the human observer. This task may be assisted with the use of image fusion algorithms. Methods In this paper, image fusion based on Kernel Principal Component Analysis (KPCA) is proposed for the first time. It is demonstrated that a priori knowledge about the data domain can be easily incorporated into the parametrisation of the KPCA, leading to task-oriented visualisations of the multivariate data. The results of the fusion process are compared with those of the well-known and established standard linear Principal Component Analysis (PCA) by means of temporal sequences of 3D MRI volumes from six patients who took part in a breast cancer screening study. Results The PCA and KPCA algorithms are able to integrate information from a sequence of MRI volumes into informative gray value or colour images. By incorporating a priori knowledge, the fusion process can be automated and optimised in order to visualise suspicious lesions with high contrast to normal tissue. Conclusion Our machine learning based image fusion approach maps the full signal space of a temporal DCE-MRI sequence to a single meaningful visualisation with good tissue/lesion contrast and thus supports the radiologist during manual image evaluation. PMID:15494072

  1. Magnetic resonance imaging for lung cancer screen.

    PubMed

    Wang, Yi-Xiang J; Lo, Gladys G; Yuan, Jing; Larson, Peder E Z; Zhang, Xiaoliang

    2014-09-01

    Lung cancer is the leading cause of cancer related death throughout the world. Lung cancer is an example of a disease for which a large percentage of the high-risk population can be easily identified via a smoking history. This has led to the investigation of lung cancer screening with low-dose helical/multi-detector CT. Evidences suggest that early detection of lung cancer allow more timely therapeutic intervention and thus a more favorable prognosis for the patient. The positive relationship of lesion size to likelihood of malignancy has been demonstrated previously, at least 99% of all nodules 4 mm or smaller are benign, while noncalcified nodules larger than 8 mm diameter bear a substantial risk of malignancy. In the recent years, the availability of high-performance gradient systems, in conjunction with phased-array receiver coils and optimized imaging sequences, has made MR imaging of the lung feasible. It can now be assumed a threshold size of 3-4 mm for detection of lung nodules with MRI under the optimal conditions of successful breath-holds with reliable gating or triggering. In these conditions, 90% of all 3-mm nodules can be correctly diagnosed and that nodules 5 mm and larger are detected with 100% sensitivity. Parallel imaging can significantly shorten the imaging acquisition time by utilizing the diversity of sensitivity profile of individual coil elements in multi-channel radiofrequency receive coil arrays or transmit/receive coil arrays to reduce the number of phase encoding steps required in imaging procedure. Compressed sensing technique accelerates imaging acquisition from dramatically undersampled data set by exploiting the sparsity of the images in an appropriate transform domain. With the combined imaging algorithm of parallel imaging and compressed sensing and advanced 32-channel or 64-channel RF hardware, overall imaging acceleration of 20 folds or higher can then be expected, ultimately achieve free-breathing and no ECG gating acquisitions

  2. Magnetic resonance imaging for lung cancer screen

    PubMed Central

    Lo, Gladys G.; Yuan, Jing; Larson, Peder E. Z.

    2014-01-01

    Lung cancer is the leading cause of cancer related death throughout the world. Lung cancer is an example of a disease for which a large percentage of the high-risk population can be easily identified via a smoking history. This has led to the investigation of lung cancer screening with low-dose helical/multi-detector CT. Evidences suggest that early detection of lung cancer allow more timely therapeutic intervention and thus a more favorable prognosis for the patient. The positive relationship of lesion size to likelihood of malignancy has been demonstrated previously, at least 99% of all nodules 4 mm or smaller are benign, while noncalcified nodules larger than 8 mm diameter bear a substantial risk of malignancy. In the recent years, the availability of high-performance gradient systems, in conjunction with phased-array receiver coils and optimized imaging sequences, has made MR imaging of the lung feasible. It can now be assumed a threshold size of 3-4 mm for detection of lung nodules with MRI under the optimal conditions of successful breath-holds with reliable gating or triggering. In these conditions, 90% of all 3-mm nodules can be correctly diagnosed and that nodules 5 mm and larger are detected with 100% sensitivity. Parallel imaging can significantly shorten the imaging acquisition time by utilizing the diversity of sensitivity profile of individual coil elements in multi-channel radiofrequency receive coil arrays or transmit/receive coil arrays to reduce the number of phase encoding steps required in imaging procedure. Compressed sensing technique accelerates imaging acquisition from dramatically undersampled data set by exploiting the sparsity of the images in an appropriate transform domain. With the combined imaging algorithm of parallel imaging and compressed sensing and advanced 32-channel or 64-channel RF hardware, overall imaging acceleration of 20 folds or higher can then be expected, ultimately achieve free-breathing and no ECG gating acquisitions

  3. 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

  4. 19F magnetic resonance imaging of endogenous macrophages in inflammation.

    PubMed

    Temme, Sebastian; Bönner, Florian; Schrader, Jürgen; Flögel, Ulrich

    2012-01-01

    In this article, we review the use of (19) F MRI (magnetic resonance imaging) for in vivo tracking of monocytes and macrophages in the course of tissue inflammation. Emulsified perfluorocarbons (PFCs) are preferentially phagocytized by monocytes/macrophages and are readily detected by (19) F MRI. Because of the lack of any (19) F background in the body, observed signals are robust and exhibit an excellent degree of specificity. As a consequence of progressive infiltration of the labeled immunocompetent cells into inflamed areas, foci of inflammation can be localized as hot spots by simultaneous acquisition of morphologically matched proton ((1) H) and fluorine ((19) F) MRI. The identification of inflammation by (19) F MRI--at a time when the inflammatory cascade is initiated--opens the possibility for an early detection and more timely therapeutic intervention. Since signal intensity in the (19) F images reflects the severity of inflammation, this approach is also suitable to monitor the efficacy of pharmaceutical treatment. Because PFCs are biochemically inert and the fluorine nucleus exhibits high magnetic resonance (MR) sensitivity, (19) F MRI may be applicable for clinical inflammation imaging. PMID:22354793

  5. 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.

  6. Low-field magnetic resonance imaging of gases

    SciTech Connect

    Schmidt, D.M.; Espy, M.A.

    1998-11-01

    This is the final report of a six-month, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The main goal of this project was to develop the capability to conduct low-field magnetic resonance imaging of hyper-polarized noble gas nuclei and of thermally polarized protons in water. The authors constructed a versatile low-field NMR system using a SQUID gradiometer detector inside a magnetically shielded room. This device has sufficient low-field sensitivity to detect the small signals associated with NMR at low magnetic fields.

  7. Contactless ultrasound detection using an optical ring resonator

    NASA Astrophysics Data System (ADS)

    Kim, Kyu Hyun; Luo, Wei; Zhang, Cheng; Guo, L. Jay; Fan, Xudong

    2016-03-01

    We develop an air-couple ultrasound detector based on an optical fluidic ring resonator (OFRR) suspended on a Ushaped holder. The OFRR is a glass capillary with an outer diameter of approximately 130 μm and a wall thickness in the order of 1~10 μm. The circular cross section of the OFRR supports the high-Q whispering gallery mode (WGM) that circulates along the circumference. Incoming ultrasound pressure results in a small refractive index change in the glass wall and geometrical change in the OFRR shape, both of which in turn lead to a spectral shift in the WGM that can be sensitively detected owing to WGM with high optical Q-factors (>107). Due to the suspension nature of the OFRR, the ultrasound detection can be carried out in air, which is advantageous in comparison with other ultrasound detections that require acoustic coupling media such water, gel or solid. The sensitivity can be tuned and optimized by changing the diameter and wall thickness. Besides the optical detection, we also demonstrate optomechanical ultrasound mixing, in which optomechanical vibration is first excited within the OFRR that subsequently modulates the ultrasound wave. Our work will lead to the development of a new type of air-coupled ultrasound detector that can be used for photo-acoustic imaging, non-invasive ultrasound detection of external objects, and ultrasound detection/characterization of internal objects (such as particles and liquids) flowing inside the capillary.

  8. 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

  9. Functional magnetic resonance imaging of the lung.

    PubMed

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

    2014-02-01

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

  10. 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

  11. Fluorescence resonance energy transfer imaging by maximum likelihood estimation

    NASA Astrophysics Data System (ADS)

    Zhang, Yupeng; Yuan, Yumin; Holmes, Timothy J.

    2004-06-01

    Fluorescence resonance energy transfer (FRET) is a fluorescence microscope imaging process involving nonradiative energy transfer between two fluorophores (the donor and the acceptor). FRET is used to detect the chemical interactions and, in some cases, measure the distance between molecules. Existing approaches do not always well compensate for bleed-through in excitation, cross-talk in emission detection and electronic noise in image acquisition. We have developed a system to automatically search for maximum-likelihood estimates of the FRET image, donor concentration and acceptor concentration. It also produces other system parameters, such as excitation/emission filter efficiency and FRET conversion factor. The mathematical model is based upon a Poisson process since the CCD camera is a photon-counting device. The main advantage of the approach is that it automatically compensates for bleed-through and cross-talk degradations. Tests are presented with synthetic images and with real data referred to as positive and negative controls, where FRET is known to occur and to not occur, respectively. The test results verify the claimed advantages by showing consistent accuracy in detecting FRET and by showing improved accuracy in calculating FRET efficiency.

  12. Hands-on resonance-enhanced photoacoustic detection

    NASA Astrophysics Data System (ADS)

    Euler, Manfred

    2001-10-01

    The design of an improved photoacoustic converter cell using kitchen equipment is described. It operates by changing manually the Helmholtz resonance frequency of bottles by adjusting the distance between the bottleneck and the outer ear. The experiment helps to gain insights in ear performance, in photoacoustic detection methods, in resonance phenomena and their role for detecting small periodic signals in the presence of noise.

  13. Magnetic resonance imaging structured reporting in infertility.

    PubMed

    Montoliu-Fornas, Guillermina; Martí-Bonmatí, Luis

    2016-06-01

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

  14. 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.

  15. Stereotactic localization using magnetic resonance imaging.

    PubMed

    Walton, L; Hampshire, A; Forster, D M; Kemeny, A A

    1995-01-01

    A phantom study has been carried out to assess the accuracy of stereotactic localisation, using magnetic resonance imaging. The stereotactic coordinates of an array of Perspex rods within the phantom were determined and compared with measured values, in a series of transverse, coronal and sagittal images. In the transverse plane, the maximum errors experienced were X = 2.3 mm and Y = 10.7 mm. If the third fiducial plate, at the front of the frame, were not used in the scaling of the images, there was considerable improvement in the Y direction (maximum error Y = 2.1 mm). However, some deterioration in the accuracy in the X direction resulted, particularly at the extremes of Z (maximum error X = 3.5 mm). In the coronal plane, the maximum errors were X = 1.8 mm and Z = 8.0 mm. With the third plate off, the errors decreased to X = 1.9 mm and Z = 3.3 mm. In the sagittal plane, the maximum errors recorded were Y = 1.1 mm and Z = 7.5 mm. It is not possible to calibrate in this plane without the third plate. PMID:8584823

  16. Optically Detected Ferromagnetic Resonance in Metallic Ferromagnets Via Off-Resonant Detection of Nitrogen Vacancy Centers in Diamond

    NASA Astrophysics Data System (ADS)

    Page, Michael R.; Bhallamudi, Vidya P.; Schulze, Joe; Purser, Carola M.; Manuilov, Sergei; Wolfe, Christopher; Brangham, Jack T.; Yang, Fengyuan; Hammel, P. Chris

    We report optical detection of ferromagnetic resonance in thin film metallic ferromagnets using a recently discovered approach employing nitrogen vacancy centers in nanodiamonds. While conventional optically detected magnetic resonance measures magnetic fields through their impact on the magnetic resonance frequency of the nitrogen vacancy center, we measure a change in the nitrogen vacancy center photoluminescence at the ferromagnet's resonance condition without need to work at the NV resonance frequency. This measurement technique allows sensitive, local detection of ferromagnetic resonance and can enable the study of magnetic dynamics at the nanoscale in a wide range of materials. While this measurement protocol was first reported in the study of ferromagnetic resonance in YIG, here we demonstrate the measurement in commonly used metallic ferromagnets to establish the generality of the technique and open the possibility of measuring nanoscale patterned devices and magnetic textures based on metallic ferromagnets of both commercial and scientific interest.

  17. Magnetic resonance imaging of heterotaxis syndrome.

    PubMed

    Stoeckelhuber, Beate M; Eckey, Thomas; Buchholz, Michael; Kapsimalakou, Smaragda; Stoeckelhuber, Mechthild

    2008-12-20

    Failure to establish normal left-right body axis (LRA) formation during embryogenesis results in heterotaxis, a multi-malformation syndrome. We report on a 20-year-old young woman who presented to the emergency room with upper abdominal pain. On chest X-ray, dextrocardia was noted. Ultrasound was inconclusive. Barium studies demonstrated non-rotation of the intestine. Magnetic resonance imaging (MRI) of the abdomen confirmed heterotaxis with abnormal arrangement of abdominal organs and vasculature. This is the first radiographic description of LRA in MRI. It provides a unique contribution to the wide morphological variety of lateralization defects in a single examination within 15 min and without the risks of ionizing radiation. In addition, a literature overview over the genetic aspects, broad morphological spectrum, and possible therapeutic consequences is given. PMID:18835766

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

    PubMed

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

    2016-01-01

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

  19. Magnetic Resonance Imaging of the Knee

    PubMed Central

    Hash, Thomas W.

    2013-01-01

    Context: Magnetic resonance imaging (MRI) affords high-resolution visualization of the soft tissue structures (menisci, ligaments, cartilage, etc) and bone marrow of the knee. Evidence Acquisition: Pertinent clinical and research articles in the orthopaedic and radiology literature over the past 30 years using PubMed. Results: Ligament tears can be accurately assessed with MRI, but distinguishing partial tears from ruptures of the anterior cruciate ligament (ACL) can be challenging. Determining the extent of a partial tear is often extremely difficult to accurately assess. The status of the posterolateral corner structures, menisci, and cartilage can be accurately evaluated, although limitations in the evaluation of certain structures exist. Patellofemoral joint, marrow, tibiofibular joint, and synovial pathology can supplement physical examination findings and provide definitive diagnosis. Conclusions: MRI provides an accurate noninvasive assessment of knee pathology. PMID:24381701

  20. Detection of rheumatoid arthritis using infrared imaging

    NASA Astrophysics Data System (ADS)

    Frize, Monique; Adéa, Cynthia; Payeur, Pierre; Di Primio, Gina; Karsh, Jacob; Ogungbemile, Abiola

    2011-03-01

    Rheumatoid arthritis (RA) is an inflammatory disease causing pain, swelling, stiffness, and loss of function in joints; it is difficult to diagnose in early stages. An early diagnosis and treatment can delay the onset of severe disability. Infrared (IR) imaging offers a potential approach to detect changes in degree of inflammation. In 18 normal subjects and 13 patients diagnosed with Rheumatoid Arthritis (RA), thermal images were collected from joints of hands, wrists, palms, and knees. Regions of interest (ROIs) were manually selected from all subjects and all parts imaged. For each subject, values were calculated from the temperature measurements: Mode/Max, Median/Max, Min/Max, Variance, Max-Min, (Mode-Mean), and Mean/Min. The data sets did not have a normal distribution, therefore non parametric tests (Kruskal-Wallis and Ranksum) were applied to assess if the data from the control group and the patient group were significantly different. Results indicate that: (i) thermal images can be detected on patients with the disease; (ii) the best joints to image are the metacarpophalangeal joints of the 2nd and 3rd fingers and the knees; the difference between the two groups was significant at the 0.05 level; (iii) the best calculations to differentiate between normal subjects and patients with RA are the Mode/Max, Variance, and Max-Min. We concluded that it is possible to reliably detect RA in patients using IR imaging. Future work will include a prospective study of normal subjects and patients that will compare IR results with Magnetic Resonance (MR) analysis.

  1. Magnetic resonance imaging of glioblastoma using aptamer conjugated magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Kim, Bongjune; Yang, Jaemoon; Hwang, Myeonghwan; Suh, Jin-Suck; Huh, Yong-Min; Haam, Seungjoo

    2012-10-01

    Here we introduce a new class of smart imaging probes hybridizing polysorbate 80 coated-magnetic nanoparticles with vascular endothelial growth factor receptor 2 (VEGFR2)-targetable aptamer for specific magnetic resonance (MR) imaging of angiogenesis from glioblastoma.

  2. 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

  3. Optically selective, acoustically resonant gas detecting transducer

    NASA Technical Reports Server (NTRS)

    Dimeff, J. (Inventor)

    1977-01-01

    A gas analyzer is disclosed which responds to the resonant absorption or emission spectrum of a specific gas by producing an acoustic resonance in a chamber containing a sample of that gas, and which measures the amount of that emission or absorption by measuring the strength of that acoustic resonance, e.g., the maximum periodic pressure, velocity or density achieved. In the preferred embodiment, a light beam is modulated periodically at the acoustical resonance frequency of a closed chamber which contains an optically dense sample of the gas of interest. Periodic heating of the absorbing gas by the light beam causes a cyclic expansion, movement, and pressure within the gas. An amplitude is reached where the increased losses were the cyclic radiation energy received. A transducing system is inclined for converting the pressure variations of the resonant gas into electronic readout signals.

  4. Infrared photothermal imaging for standoff detection applications

    NASA Astrophysics Data System (ADS)

    Kendziora, C. A.; Jones, Robert M.; Furstenberg, Robert; Papantonakis, Michael; Nguyen, Viet; McGill, R. Andrew

    2012-06-01

    We are developing a technique for the stand-off detection of trace analytes and residues (explosives, hazardous chemicals, drugs, etc.) using photo-thermal infrared imaging spectroscopy (PT-IRIS). Herein, we refer to this technique as "RED" for "Remote Explosives Detection" or "Resonance Enhanced Detection". This approach leverages recent developments in critical enabling micro and nano-technology components. The first component, a compact IR quantum cascade laser (QCL), is tuned to fundamental absorption bands in the analytes and directed to illuminate a surface of interest. The second component, an IR focal plane array (FPA), is used to image the surface and detect any small increase in the thermal emission upon laser illumination. We have demonstrated the technique at up to 30 meters of stand-off distance indoors and in field tests, while operating the lasers below the eye-safe intensity limit (100 mW/cm2). In this manuscript we detail several recent improvements to the method and system, as well as some recent results for explosives on complex substrates such as car panels and fabrics. We also introduce a computational framework for modeling and simulating the optical and thermal phenomena associated with the photothermal process.

  5. Fetal magnetic resonance imaging and ultrasound.

    PubMed

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

    2016-07-01

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

  6. Resonant Doppler imaging with common path OCT

    NASA Astrophysics Data System (ADS)

    Koch, Edmund; Hammer, Daniel; Wang, Siqian; Cuevas, Maximiliano; Walther, Julia

    2009-07-01

    Resonant Doppler flow imaging based on optical coherence tomography (OCT) is a recently developed imaging modality that provides, besides the structural information, dynamic blood flow information. We show that this method can be applied to a common path OCT system by mounting the mirror in the reference arm on a small piezo actor leading to a simpler and more stable system design. Besides the known 3 state cycle, we describe other cycles with any number of states leading to higher measurement speed or larger velocity range. The hysteresis of the piezo actor is compensated by applying an optimized electrical signal. Two different approaches, one using a Levenberg-Marquardt optimization, the other using the Prandtl-Ishlinskii model for compensation of hysteresis, are applied to generate the optimized control signal. Besides providing an analytical formula for the calculation of the axial velocity for cycles having certain spacings in the reference velocity, we describe deviations from the signal degradation caused by the transversal part of the motion causing errors in the velocity estimation. The performance of the system with two and three states is first evaluated with a mirror on a loud speaker. Measurements with a flow phantom consisting of 1 % Intralipid dilution flowing through small diameter capillaries show the suitability of the system and the expected deviations at high velocities.

  7. Spin wave resonance detection using magnetic tunnel junction structure

    NASA Astrophysics Data System (ADS)

    Bi, Chong; Fan, Xin; Pan, Liqing; Kou, Xiaoming; Wu, Jun; Yang, Qinghui; Zhang, Huaiwu; Xiao, John Q.

    2011-11-01

    We have demonstrated that spin wave resonance in a permalloy microstrip can be detected by an electrical method based on magnetic tunnel junction structures. The detection method promises high spatial resolution and sensitivity. Both even and odd spin wave resonance modes can be clearly observed in a permalloy microstrip. The spin wave induced voltage is proportional to the input microwave power at each resonance mode. Data analysis using the model of quantized dipole-exchange spin wave resonance suggests the edge pinning of spin wave sensitively depends on the order of the spin wave mode, as well as on the excitation frequency for modes of the higher order.

  8. Extrafetal Findings on Fetal Magnetic Resonance Imaging: A Pictorial Essay.

    PubMed

    Epelman, Monica; Merrow, Arnold C; Guimaraes, Carolina V; Victoria, Teresa; Calvo-Garcia, Maria A; Kline-Fath, Beth M

    2015-12-01

    Although US is the mainstay of fetal imaging, magnetic resonance imaging (MRI) has become an invaluable adjunct in recent years. MRI offers superb soft tissue contrast that allows for detailed evaluation of fetal organs, particularly the brain, which enhances understanding of disease severity. MRI can yield results that are similar to or even better than those of US, particularly in cases of marked oligohydramnios, maternal obesity, or adverse fetal positioning. Incidentally detected extrafetal MRI findings are not uncommon and may affect clinical care. Physicians interpreting fetal MRI studies should be aware of findings occurring outside the fetus, including those structures important for the pregnancy. A systematic approach is necessary in the reading of such studies. This helps to ensure that important findings are not missed, appropriate clinical management is implemented, and unnecessary follow-up examinations are avoided. In this pictorial essay, the most common extrafetal abnormalities are described and illustrated. PMID:26614136

  9. Prostate cancer risk stratification with magnetic resonance imaging.

    PubMed

    Felker, Ely R; Margolis, Daniel J; Nassiri, Nima; Marks, Leonard S

    2016-07-01

    In recent years, multiparametric magnetic resonance imaging (mpMRI) has shown promise for prostate cancer (PCa) risk stratification. mpMRI, often followed by targeted biopsy, can be used to confirm low-grade disease before enrollment in active surveillance. In patients with intermediate or high-risk PCa, mpMRI can be used to inform surgical management. mpMRI has sensitivity of 44% to 87% for detection of clinically significant PCa and negative predictive value of 63% to 98% for exclusion of significant disease. In addition to tumor identification, mpMRI has also been shown to contribute significant incremental value to currently used clinical nomograms for predicting extraprostatic extension. In combination with conventional clinical criteria, accuracy of mpMRI for prediction of extraprostatic extension ranges from 92% to 94%, significantly higher than that achieved with clinical criteria alone. Supplemental sequences, such as diffusion-weighted imaging and dynamic contrast-enhanced imaging, allow quantitative evaluation of cancer-suspicious regions. Apparent diffusion coefficient appears to be an independent predictor of PCa aggressiveness. Addition of apparent diffusion coefficient to Epstein criteria may improve sensitivity for detection of significant PCa by as much as 16%. Limitations of mpMRI include variability in reporting, underestimation of PCa volume and failure to detect clinically significant disease in a small but significant number of cases. PMID:27040381

  10. Real-time magnetic resonance imaging investigation of resonance tuning in soprano singing.

    PubMed

    Bresch, Erik; Narayanan, Shrikanth

    2010-11-01

    This article investigates using real-time magnetic resonance imaging the vocal tract shaping of 5 soprano singers during the production of two-octave scales of sung vowels. A systematic shift of the first vocal tract resonance frequency with respect to the fundamental is shown to exist for high vowels across all subjects. No consistent systematic effect on the vocal tract resonance could be shown across all of the subjects for other vowels or for the second vocal tract resonance. PMID:21110548

  11. 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.

  12. Unsupervised detection of abnormalities in medical images using salient features

    NASA Astrophysics Data System (ADS)

    Alpert, Sharon; Kisilev, Pavel

    2014-03-01

    In this paper we propose a new method for abnormality detection in medical images which is based on the notion of medical saliency. The proposed method is general and is suitable for a variety of tasks related to detection of: 1) lesions and microcalcifications (MCC) in mammographic images, 2) stenoses in angiographic images, 3) lesions found in magnetic resonance (MRI) images of brain. The main idea of our approach is that abnormalities manifest as rare events, that is, as salient areas compared to normal tissues. We define the notion of medical saliency by combining local patch information from the lightness channel with geometric shape local descriptors. We demonstrate the efficacy of the proposed method by applying it to various modalities, and to various abnormality detection problems. Promising results are demonstrated for detection of MCC and of masses in mammographic images, detection of stenoses in angiography images, and detection of lesions in brain MRI. We also demonstrate how the proposed automatic abnormality detection method can be combined with a system that performs supervised classification of mammogram images into benign or malignant/premalignant MCC's. We use a well known DDSM mammogram database for the experiment on MCC classification, and obtain 80% accuracy in classifying images containing premalignant MCC versus benign ones. In contrast to supervised detection methods, the proposed approach does not rely on ground truth markings, and, as such, is very attractive and applicable for big corpus image data processing.

  13. Parallel-scan based microarray imager capable of simultaneous surface plasmon resonance and hyperspectral fluorescence imaging.

    PubMed

    Liu, Zhiyi; Yang, Lei; Liu, Le; Chong, Xinyuan; Guo, Jun; Ma, Suihua; Ji, Yanhong; He, Yonghong

    2011-12-15

    With the development of the microarray technology, demands for array detection techniques become higher and higher. For many microarrays, several biomolecular interactions occur simultaneously and the interplay of various factors that affect these interactions remains poorly understood. Detecting such interactions with a single technique can often be a difficult and complicated process. In this work we propose a combined technique which enables simultaneous angle-interrogation surface plasmon resonance (SPR) sensing and hyperspectral fluorescence imaging. This tandem technique offers two-dimensional imaging of the whole array plane. The refractive index information obtained from SPR sensing and the physicochemical properties obtained from fluorescence imaging provide a comprehensive analysis of biological events on the array-chip. In addition, SPR and fluorescence detection techniques confirm each other in experimental results to exclude false-positive or false-negative cases. In terms of SPR sensing performance, the refractive index resolution is 3.86×10(-6) refractive index units (RIU), and the detection limit is 10(4) cfu/ml of Escherichia coli bacteria. The resolving power and detection sensitivity of fluorescence imaging are approximately 20 μm and 0.61 fluors/μm(2), respectively. Finally, two model experiments, detecting the DNA hybridization and biotin-avidin interactions respectively, demonstrate the biomedical application of this system. PMID:21996322

  14. Dark-field microscopy in imaging of plasmon resonant nanoparticles.

    PubMed

    Liu, Mengmeng; Chao, Jie; Deng, Suhui; Wang, Kun; Li, Kun; Fan, Chunhai

    2014-12-01

    Dark-field microscopy (DFM) and spectroscopy base on localized surface plasmon resonance (LSPR) have been widely applied in biological sensing and single-molecule imaging. Using plasmonic nanoparticles with controlled geometrical, optical, and surface chemical properties as the probes, the scattering light depending on the surrounding environment can be detected by DF microscope. Signal-to-noise radio and time resolution of the conventional DFM is not sufficient to identify single molecular dynamics. To break these limitations, significant improvements have been made in recent years. This critical review is focused on the developments of the DFM and the utilization of DFM as a powerful technology in the application of LSPR detection. PMID:25009105

  15. Diagnostic imaging of psoriatic arthritis. Part II: magnetic resonance imaging and ultrasonography

    PubMed Central

    Pracoń, Grzegorz

    2016-01-01

    Plain radiography reveals specific, yet late changes of advanced psoriatic arthritis. Early inflammatory changes are seen both on magnetic resonance imaging and ultrasound within peripheral joints (arthritis, synovitis), tendons sheaths (tenosynovitis, tendovaginitis) and entheses (enthesitis, enthesopathy). In addition, magnetic resonance imaging enables the assessment of inflammatory features in the sacroiliac joints (sacroiliitis), and the spine (spondylitis). In this article, we review current opinions on the diagnostics of some selective, and distinctive features of psoriatic arthritis concerning magnetic resonance imaging and ultrasound and present some hypotheses on psoriatic arthritis etiopathogenesis, which have been studied with the use of magnetic resonance imaging. The following elements of the psoriatic arthritis are discussed: enthesitis, extracapsular inflammation, dactylitis, distal interphalangeal joint and nail disease, and the ability of magnetic resonance imaging to differentiate undifferentiated arthritis, the value of whole-body magnetic resonance imaging and dynamic contrast-enhanced magnetic resonance imaging. PMID:27446601

  16. Authenticity detection in image classification

    NASA Astrophysics Data System (ADS)

    Nova, Luis C.; Passos, Emmanuel P. L.

    1992-09-01

    Famous artists' paintings, in general, allow for a large number of forgeries. In the work of a great Brazilian painter, Candido Portinari, we try to detect fake works through their image. To reach classifying results we must extract from digitalized images features that distinguish Portinari's original paintings from the false ones. So, it has been noted that the degree of variation of gray tones in a brush stroke reflects each painter's particular style on the painting. It is a feature that can be easily detected by the power spectrum of the detail image. However, as power spectra have large amounts of data, we use just some significant values of them for the classification. These selected pixels of the spectrum image are in a line which is perpendicular to the direction the brush passed, i.e., they indicate the variation of gray tones in the brush stroke. The data described previously are used as input for further classification by a backpropagation neural network. This neural net was exhaustively trained and has topology and parameters appropriate to the problem. Two output units indicate the major result: original or false.

  17. Trends in infrared imaging detecting technology

    NASA Astrophysics Data System (ADS)

    Fan, Jinxiang; Yang, Jianyu

    2013-10-01

    In this paper, the current status of infrared imaging detecting technology was introduced briefly. The impact of changes of target, environment and mission on the development of infrared imaging detecting technology was analyzed. The main innovation strategies of infrared imaging detecting technology-modifying information acquisition mode, enhancing realization ability and increasing resources utilization were discussed. The promoting effects of the advancement of basic theories and the revolution of relevant technologies on the development of infrared imaging detecting technology were analyzed. The fundamental law of the development of infrared imaging detecting technology was summarized as stepwise evolution from low into high dimension detection. And the developing trends and main characteristics of future infrared imaging detecting technology were deduced based on this fundamental law. Furthermore, technology directions that should be concerned were introduced according to the development of new concept and technologies for infrared imaging detecting, especially, meeting the new requirements through new concept imaging mechanism such as novel optical technology and computing imaging.

  18. Endoluminal contrast for abdomen and pelvis magnetic resonance imaging.

    PubMed

    Gupta, Mohit K; Khatri, Gaurav; Bailey, April; Pinho, Daniella F; Costa, Daniel; Pedrosa, Ivan

    2016-07-01

    Magnetic resonance (MR) imaging of the abdomen and pelvis can be limited for assessment of different conditions when imaging inadequately distended hollow organs. Endoluminal contrast agents may provide improved anatomic definition and detection of subtle pathology in such scenarios. The available routes of administration for endoluminal contrast agents include oral, endorectal, endovaginal, intravesicular, and through non-physiologic accesses. Appropriate use of endoluminal contrast agents requires a thorough understanding of the clinical indications, available contrast agents, patient preparation, and interaction of the contrast agent with the desired MR imaging protocol. For example, biphasic oral enteric contrast agents are preferred in MR enterography as their signal properties on T1- and T2-weighted imaging allow for evaluation of both intraluminal and bowel wall pathology. In specific situations such as with MR enterography, MR defecography, and accurate local staging of certain pelvic tumors, the use of an endoluminal contrast agent is imperative in providing adequate diagnostic imaging. In other clinical scenarios, the use of an endoluminal contrast agent may serve as an indispensable problem-solving tool. PMID:26907710

  19. 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

  20. Rapid eye movement-related brain activation in human sleep: a functional magnetic resonance imaging study.

    PubMed

    Wehrle, Renate; Czisch, Michael; Kaufmann, Christian; Wetter, Thomas C; Holsboer, Florian; Auer, Dorothee P; Pollmächer, Thomas

    2005-05-31

    In animal models, ponto-geniculo-occipital waves appear as an early sign of rapid eye movement sleep and may be functionally significant for brain plasticity processes. In this pilot study, we use a combined polysomnographic and functional magnetic resonance imaging approach, and show distinct magnetic resonance imaging signal increases in the posterior thalamus and occipital cortex in close temporal relationship to rapid eye movements during human rapid eye movement sleep. These findings are consistent with cell recordings in animal experiments and demonstrate that functional magnetic resonance imaging can be utilized to detect ponto-geniculo-occipital-like activity in humans. Studying intact neuronal networks underlying sleep regulation is no longer confined to animal models, but has been shown to be feasible in humans by a combined functional magnetic resonance imaging and electroencephalograph approach. PMID:15891584

  1. Magnetic resonance imaging findings of neuroaxonal dystrophy in a papillon puppy.

    PubMed

    Tamura, S; Tamura, Y; Uchida, K

    2007-08-01

    A 3.5-month-old papillon puppy was brought to our clinic with chief complaints of progressive quadriparesis, ataxia and head tremor. Lesions in the cerebellum, brainstem and spinal cord were suspected on the basis of a neurological examination. No abnormality was found in a clinicopathological examination or on magnetic resonance imaging. On the basis of these results differential diagnoses including an inflammatory disease, a degenerative condition or a storage disorder were considered. Subsequently, the signs progressed and glossoplegia and dysphagia developed at six months of age. At a second magnetic resonance imaging, severe atrophy of the entire brain was found. After these examinations, the puppy was euthanased and histopathologically diagnosed with neuroaxonal dystrophy. Because magnetic resonance imaging detected abnormal features that were characteristic of neuroaxonal dystrophy in this case, we speculate that magnetic resonance imaging can assist in the pre-mortem diagnosis of this disease. PMID:17543020

  2. Prototype explosives detection system based on nuclear resonance absorption in nitrogen

    SciTech Connect

    Morgado, R.E.; Arnone, G.J.; Cappiello, C.C.

    1996-05-01

    A laboratory prototype system has been developed for the experimental evaluation of an explosives detection technique based on nuclear resonance absorption of gamma rays in nitrogen. Major subsystems include a radiofrequency quadrupole proton accelerator and associated beam transport system, a high-power gamma-ray production target, an airline-luggage tomographic inspection system, and an image- processing/detection-alarm subsystem. The detection system performance, based on a limited experimental test, is reported.

  3. Resonant microwave cavity for 8.5-12 GHz optically detected electron spin resonance with simultaneous nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Colton, J. S.; Wienkes, L. R.

    2009-03-01

    We present a newly developed microwave resonant cavity for use in optically detected magnetic resonance (ODMR) experiments. The cylindrical quasi-TE011 mode cavity is designed to fit in a 1 in. magnet bore to allow the sample to be optically accessed and to have an adjustable resonant frequency between 8.5 and 12 GHz. The cavity uses cylinders of high dielectric material, so-called "dielectric resonators," in a double-stacked configuration to determine the resonant frequency. Wires in a pseudo-Helmholtz configuration are incorporated into the cavity to provide frequencies for simultaneous nuclear magnetic resonance (NMR). The system was tested by measuring cavity absorption as microwave frequencies were swept, by performing ODMR on a zinc-doped InP sample, and by performing optically detected NMR on a GaAs sample. The results confirm the suitability of the cavity for ODMR with simultaneous NMR.

  4. Diffusion-weighted imaging in pediatric body magnetic resonance imaging.

    PubMed

    Chavhan, Govind B; Caro-Dominguez, Pablo

    2016-05-01

    Diffusion-weighted MRI is being increasingly used in pediatric body imaging. Its role is still emerging. It is used for detection of tumors and abscesses, differentiation of benign and malignant tumors, and detection of inflamed bowel segments in inflammatory bowel disease in children. It holds great promise in the assessment of therapy response in body tumors, with apparent diffusion coefficient (ADC) value as a potential biomarker. Significant overlap of ADC values of benign and malignant processes and less reproducibility of ADC measurements are hampering its widespread use in clinical practice. With standardization of the technique, diffusion-weighted imaging (DWI) is likely to be used more frequently in clinical practice. We discuss the principles and technique of DWI, selection of b value, qualitative and quantitative assessment, and current status of DWI in evaluation of disease processes in the pediatric body. PMID:27229502

  5. Beyond Histologic Staging: Emerging Imaging Strategies in Colorectal Cancer with Special Focus on Magnetic Resonance Imaging.

    PubMed

    Fraum, Tyler J; Owen, Joseph W; Fowler, Kathryn J

    2016-09-01

    Imaging plays an increasingly important role in the staging and management of colorectal cancer. In recent years, magnetic resonance imaging (MRI) has supplanted transrectal ultrasound as the preferred modality for the locoregional staging of rectal cancer. Furthermore, the advent of both diffusion-weighted imaging and hepatobiliary contrast agents has significantly enhanced the ability of MRI to detect colorectal liver metastases. In clinical practice, MRI routinely provides prognostic information, helps to guide surgical strategy, and determines the need for neoadjuvant therapies related to both the primary tumor and metastatic disease. Expanding on these roles for MRI, positron emission tomography (PET)/MRI is the newest clinical hybrid imaging modality and combines the metabolic information of PET with the high soft tissue contrast of MRI. The addition of PET/MRI to the clinical staging armamentarium has the potential to provide comprehensive state-of-the-art colorectal cancer staging in a single examination. PMID:27582645

  6. 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.

  7. Silent cerebral infarct after cardiac catheterization as detected by diffusion weighted Magnetic Resonance Imaging: a randomized comparison of radial and femoral arterial approaches

    PubMed Central

    Hamon, Michèle; Burzotta, Francesco; Oppenheim, Catherine; Morello, Rémy; Viader, Fausto; Hamon, Martial

    2007-01-01

    Background and objective Cerebral microembolism detected by transcranial Doppler (TCD) occurs systematically during cardiac catheterization, but its clinical relevance, remains unknown. Studies suggest that asymptomatic embolic cerebral infarction detectable by diffusion-weighted (DW) MRI might exist after percutaneous cardiac interventions with a frequency as high as 15 to 22% of cases. We have set up, for the first time, a prospective multicenter trial to assess the rate of silent cerebral infarction after cardiac catheterization and to compare the impact of the arterial access site, comparing radial and femoral access, on this phenomenon. Study design This prospective study will be performed in patients with severe aortic valve stenosis. To assess the occurrence of cerebral infarction, all patients will undergo cerebral DW-MRI and neurological assessment within 24 hours before, and 48 hours after cardiac catheterization and retrograde catheterization of the aortic valve. Randomization for the access site will be performed before coronary angiography. A subgroup will be monitored by transcranial power M-mode Doppler during cardiac catheterization to observe cerebral blood flow and track emboli. Neuropsychological tests will also be recorded in a subgroup of patients before and after the interventional procedures to assess the impact of silent brain injury on potential cognitive decline. The primary end-point of the study is a direct comparison of ischemic cerebral lesions as detected by serial cerebral DW-MRI between patients explored by radial access and patients explored by femoral access. Secondary end-points include comparison of neuropsychological test performance and number of microembolism signals observed in the two groups. Implications Using serial DW-MRI, silent cerebral infarction rate will be defined and the potential influence of vascular access site will be evaluated. Silent cerebral infarction might be a major concern during cardiac catheterization

  8. 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.

  9. Magnetic resonance imaging in brachial plexus injury.

    PubMed

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

    2013-08-01

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

  10. Magnetic Resonance Imaging of Cartilage Repair

    PubMed Central

    Trattnig, Siegfried; Winalski, Carl S.; Marlovits, Stephan; Jurvelin, Jukka S.; Welsch, Goetz H.; Potter, Hollis G.

    2011-01-01

    Articular cartilage lesions are a common pathology of the knee joint, and many patients may benefit from cartilage repair surgeries that offer the chance to avoid the development of osteoarthritis or delay its progression. Cartilage repair surgery, no matter the technique, requires a noninvasive, standardized, and high-quality longitudinal method to assess the structure of the repair tissue. This goal is best fulfilled by magnetic resonance imaging (MRI). The present article provides an overview of the current state of the art of MRI of cartilage repair. In the first 2 sections, preclinical and clinical MRI of cartilage repair tissue are described with a focus on morphological depiction of cartilage and the use of functional (biochemical) MR methodologies for the visualization of the ultrastructure of cartilage repair. In the third section, a short overview is provided on the regulatory issues of the United States Food and Drug Administration (FDA) and the European Medicines Agency (EMEA) regarding MR follow-up studies of patients after cartilage repair surgeries. PMID:26069565

  11. Acoustic detection of electron spin resonance

    NASA Astrophysics Data System (ADS)

    Coufal, H.

    1981-07-01

    The ESR-signal of DPPH was recorded by detecting the modulation of the absorbed microwave power with a gas-coupled microphone. This photo-acoustic detection scheme is compared with conventional ESR-detection. Applications of the acoustical detection method to other modulation spectroscopic techniques, particularly NMR, are discussed.

  12. Buried object detection in GPR images

    SciTech Connect

    Paglieroni, David W; Chambers, David H; Bond, Steven W; Beer, W. Reginald

    2014-04-29

    A method and system for detecting the presence of subsurface objects within a medium is provided. In some embodiments, the imaging and detection system operates in a multistatic mode to collect radar return signals generated by an array of transceiver antenna pairs that is positioned across the surface and that travels down the surface. The imaging and detection system pre-processes the return signal to suppress certain undesirable effects. The imaging and detection system then generates synthetic aperture radar images from real aperture radar images generated from the pre-processed return signal. The imaging and detection system then post-processes the synthetic aperture radar images to improve detection of subsurface objects. The imaging and detection system identifies peaks in the energy levels of the post-processed image frame, which indicates the presence of a subsurface object.

  13. A Review of Imaging Methods for Prostate Cancer Detection

    PubMed Central

    Sarkar, Saradwata; Das, Sudipta

    2016-01-01

    Imaging is playing an increasingly important role in the detection of prostate cancer (PCa). This review summarizes the key imaging modalities—multiparametric ultrasound (US), multiparametric magnetic resonance imaging (MRI), MRI–US fusion imaging, and positron emission tomography (PET) imaging—used in the diagnosis and localization of PCa. Emphasis is laid on the biological and functional characteristics of tumors that rationalize the use of a specific imaging technique. Changes to anatomical architecture of tissue can be detected by anatomical grayscale US and T2-weighted MRI. Tumors are known to progress through angiogenesis—a fact exploited by Doppler and contrast-enhanced US and dynamic contrast-enhanced MRI. The increased cellular density of tumors is targeted by elastography and diffusion-weighted MRI. PET imaging employs several different radionuclides to target the metabolic and cellular activities during tumor growth. Results from studies using these various imaging techniques are discussed and compared. PMID:26966397

  14. Mechanical detection of electron spin resonance beyond 1 THz

    SciTech Connect

    Takahashi, Hideyuki; Ohmichi, Eiji; Ohta, Hitoshi

    2015-11-02

    We report the cantilever detection of electron spin resonance (ESR) in the terahertz (THz) region. This technique mechanically detects ESR as a change in magnetic torque that acts on the cantilever. The ESR absorption of a tiny single crystal of Co Tutton salt, Co(NH{sub 4}){sub 2}(SO{sub 4}){sub 2}⋅6H{sub 2}O, was observed in frequencies of up to 1.1 THz using a backward travelling wave oscillator as a THz-wave source. This is the highest frequency of mechanical detection of ESR till date. The spectral resolution was evaluated with the ratio of the peak separation to the sum of the half-width at half maximum of two absorption peaks. The highest resolution value of 8.59 ± 0.53 was achieved at 685 GHz, while 2.47 ± 0.01 at 80 GHz. This technique will not only broaden the scope of ESR spectroscopy application but also lead to high-spectral-resolution ESR imaging.

  15. 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 μg/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 μg/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

  16. Quantifying mixing using magnetic resonance imaging.

    PubMed

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

    2012-01-01

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

  17. Quantifying Mixing using Magnetic Resonance Imaging

    PubMed Central

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

    2012-01-01

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

  18. Electron-paramagnetic resonance detection with software time locking

    NASA Astrophysics Data System (ADS)

    Aloisi, Giovanni; Mannini, Matteo; Caneschi, Andrea; Dolci, David; Carlà, Marcello

    2014-02-01

    A setup for electron paramagnetic resonance with narrow band digital detection is described. A low frequency reference tone is added to the radio frequency signal. This reference signal, after digital detection, is used to lock the resonance signal, even in the absence of hardware time locking among the radio frequency generator, the conversion local oscillators, and the sampling stage. Results obtained with 2,2-Diphenyl-1-Pycryl-Hydrazil are presented and discussed.

  19. Nuclear magnetic resonance imaging in patients with cardiac pacing devices.

    PubMed

    Buendía, Francisco; Sánchez-Gómez, Juan M; Sancho-Tello, María J; Olagüe, José; Osca, Joaquín; Cano, Oscar; Arnau, Miguel A; Igual, Begoña

    2010-06-01

    Currently, nuclear magnetic resonance imaging is contraindicated in patients with a pacemaker or implantable cardioverter-defibrillator. This study was carried out because the potential risks in this situation need to be clearly defined. This prospective study evaluated clinical and electrical parameters before and after magnetic resonance imaging was performed in 33 patients (five with implantable cardioverter-defibrillators and 28 with pacemakers). In these patients, magnetic resonance imaging was considered clinically essential. There were no clinical complications. There was a temporary communication failure in two cases, sensing errors during imaging in two cases, and a safety signal was generated in one pacemaker at the maximum magnetic resonance frequency and output level. There were no technical restrictions on imaging nor were there any permanent changes in the performance of the cardiac pacing device. PMID:20515632

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

    PubMed Central

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

    2016-01-01

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

  1. Magnetic resonance imaging of microvessels using iron-oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Olamaei, N.; Cheriet, F.; Martel, S.

    2013-03-01

    The visualization of microstructures including blood vessels with an inner overall cross-sectional area below approximately 200 μm remains beyond the capabilities of current clinical imaging modalities. But with magnetic resonance (MR) imaging, magnetic entities cause susceptibility artifacts in the images by disrupting the homogeneous magnetic field in a much larger scale than their actual size. As validated in this paper through simulation and in-vitro experiments, these artifacts can serve as a source of contrast, enabling microvessels with an inner diameter below the spatial resolution of any medical imaging modalities to be visualized using a clinical MR scanner. For such experiments, micron-sized agglomerations of iron-oxide (Fe3O4) nanoparticles were injected in microchannels with internal diameters of 200 and 50 μm equivalent to a narrower artery or a larger arteriole, and down to a smaller arteriole, respectively. The results show the feasibility of the proposed method for micro-particle detection and the visualization of microvessels using a 1.5 T clinical MR scanner. It was confirmed that the method is reproducible and accurate at the sub-pixel level.

  2. Multiparametric Magnetic Resonance Imaging of Recurrent Prostate Cancer

    PubMed Central

    Oppenheimer, Daniel Corey; Weinberg, Eric P; Hollenberg, Gary M; Meyers, Steven P

    2016-01-01

    Multiparametric magnetic resonance (MR) imaging of the prostate combines both morphological and functional MR techniques by utilizing small field of view T1-weighted, T2-weighted, diffusion-weighted imaging, dynamic contrast-enhanced imaging, and MR spectroscopy to accurately detect, localize, and stage primary and recurrent prostate cancer. Localizing the site of recurrence in patients with rising prostate-specific antigen following treatment affects decision making regarding treatment and can be accomplished with multiparametric prostate MR. Several different treatment options are available for prostate cancer including radical prostatectomy, external beam radiation therapy, brachytherapy, androgen deprivation therapy, or a number of focal therapy techniques. The findings of recurrent prostate cancer can be different depending on the treatment the patient has received, and the radiologist must be able to recognize the variety of imaging findings seen with this common disease. This review article will detail the findings of recurrent prostate cancer on multiparametric MR and describe common posttreatment changes which may create challenges to accurate interpretation. PMID:27195184

  3. Nanometric resolution magnetic resonance imaging methods for mapping functional activity in neuronal networks

    PubMed Central

    Boretti, Albert; Castelletto, Stefania

    2016-01-01

    This contribution highlights and compares some recent achievements in the use of k-space and real space imaging (scanning probe and wide-filed microscope techniques), when applied to a luminescent color center in diamond, known as nitrogen vacancy (NV) center. These techniques combined with the optically detected magnetic resonance of NV, provide a unique platform to achieve nanometric magnetic resonance imaging (MRI) resolution of nearby nuclear spins (known as nanoMRI), and nanometric NV real space localization. • Atomic size optically detectable spin probe. • High magnetic field sensitivity and nanometric resolution. • Non-invasive mapping of functional activity in neuronal networks. PMID:27144128

  4. Nanometric resolution magnetic resonance imaging methods for mapping functional activity in neuronal networks.

    PubMed

    Boretti, Albert; Castelletto, Stefania

    2016-01-01

    This contribution highlights and compares some recent achievements in the use of k-space and real space imaging (scanning probe and wide-filed microscope techniques), when applied to a luminescent color center in diamond, known as nitrogen vacancy (NV) center. These techniques combined with the optically detected magnetic resonance of NV, provide a unique platform to achieve nanometric magnetic resonance imaging (MRI) resolution of nearby nuclear spins (known as nanoMRI), and nanometric NV real space localization. •Atomic size optically detectable spin probe.•High magnetic field sensitivity and nanometric resolution.•Non-invasive mapping of functional activity in neuronal networks. PMID:27144128

  5. Broadband electrically detected magnetic resonance using adiabatic pulses.

    PubMed

    Hrubesch, F M; Braunbeck, G; Voss, A; Stutzmann, M; Brandt, M S

    2015-05-01

    We present a broadband microwave setup for electrically detected magnetic resonance (EDMR) based on microwave antennae with the ability to apply arbitrarily shaped pulses for the excitation of electron spin resonance (ESR) and nuclear magnetic resonance (NMR) of spin ensembles. This setup uses non-resonant stripline structures for on-chip microwave delivery and is demonstrated to work in the frequency range from 4 MHz to 18 GHz. π pulse times of 50 ns and 70 μs for ESR and NMR transitions, respectively, are achieved with as little as 100 mW of microwave or radiofrequency power. The use of adiabatic pulses fully compensates for the microwave magnetic field inhomogeneity of the stripline antennae, as demonstrated with the help of BIR4 unitary rotation pulses driving the ESR transition of neutral phosphorus donors in silicon and the NMR transitions of ionized phosphorus donors as detected by electron nuclear double resonance (ENDOR). PMID:25828243

  6. Improving the detection sensitivity of chromatography by stochastic resonance.

    PubMed

    Zhang, Wei; Guo, Jianru; Xiang, Bingren; Fan, Hongyan; Xu, Fengguo

    2014-05-01

    Improving the detection sensitivity of analytical instruments has been a challenging task for chemometricians since undetectability has been almost unavoidable in trace analysis, even under optimized experimental conditions and with the use of modern instruments. Various chemometrics methods have been developed which attempt to address this detection problem but with limited success (e.g., fast Fourier transform and wavelet transform). However, the application of stochastic resonance (SR) creates an entirely new and effective methodology. Stochastic resonance is a phenomenon which is manifested in non-linear systems where a weak signal can be amplified and optimized with the assistance of noise. In this review, we summarize the use of basic SR, optimization of parameters and its modifications, including periodic modulation stochastic resonance (PSRA), linear modulation stochastic resonance (LSRA), single-well potential stochastic resonance (SSR) and the Duffing oscillator algorithm (DOA) for amplifying sub-threshold small signals. We also review the advantages and the disadvantages of various SR procedures. PMID:24622614

  7. Magnetic resonance imaging in entomology: a critical review

    PubMed Central

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

    2003-01-01

    Magnetic resonance imaging (MRI) enables in vivo imaging of organisms. The recent development of the magnetic resonance microscope (MRM) has enabled organisms within the size range of many insects to be imaged. Here, we introduce the principles of MRI and MRM and review their use in entomology. We show that MRM has been successfully applied in studies of parasitology, development, metabolism, biomagnetism and morphology, and the advantages and disadvantages relative to other imaging techniques are discussed. In addition, we illustrate the images that can be obtained using MRM. We conclude that although MRM has significant potential, further improvements to the technique are still desirable if it is to become a mainstream imaging technology in entomology. Abbreviation: CSI chemical shift imaging. The dependence of the resonance frequency of a nucleus on the chemical binding of the atom or molecule in which it is contained. (N)MRI (nuclear) magnetic resonance imaging MRM magnetic resonance microscopy Voxel A contraction for volume element, which is the basic unit of MR reconstruction; represented as a pixel in the display of the MR image. PMID:15841222

  8. Patellar tendinitis: the significance of magnetic resonance imaging findings.

    PubMed

    Shalaby, M; Almekinders, L C

    1999-01-01

    We evaluated the significance of magnetic resonance imaging findings in patients with patellar tendinitis. Midline sagittal magnetic resonance images were taken of 12 knees from 10 patients and of 17 knees from 15 age- and activity-matched subjects who underwent imaging for reasons other than patellar tendinitis. Of the 12 magnetic resonance imaging scans of knees with clinical patellar tendinitis, 3 (25%) exhibited no defect and only 7 (58%) had unequivocal intratendinous lesions. Among the 17 scans of subjects without clinical patellar tendinitis, 5 (34%) showed no defect and 4 (24%) had unequivocal intratendinous lesions. Proximal tendon width was significantly larger for the tendinitis patient group (5.0 +/- 1.7 mm versus 3.9 +/- 1.0 mm), although considerable overlap was present. All subjects with unequivocal intratendinous signal changes had a significantly longer nonarticular inferior patellar pole and were significantly older (38.1 years versus 26.8 years). Only Blazina stage III lesions were associated with abnormal findings on magnetic resonance imaging. As a whole, the sensitivity and specificity of magnetic resonance imaging was 75% and 29%, respectively. In younger patients with relatively mild symptoms, magnetic resonance imaging did not show significant changes; in older, active patients changes may be present in asymptomatic knees. PMID:10352771

  9. 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

  10. 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.

  11. 76 FR 58281 - Magnetic Resonance Imaging Safety; Public Workshop

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-20

    ... the safe use of magnetic resonance imaging (MRI) and approaches to mitigate risks. The overall goal is... overview of the Connect Pro program, visit: http://www.adobe.com/go/connectpro_overview . (FDA has...

  12. Ultrasensitive and selective detection of mercury (II) in serum based on the gold film sensor using a laser scanning confocal imaging-surface plasmon resonance system in real time

    NASA Astrophysics Data System (ADS)

    Liu, Sha; Zhang, Hongyan; Liu, Weimin; Wang, Pengfei

    2015-10-01

    Hg2+ ions are one of the most toxic heavy metal ion pollutants, and are caustic and carcinogenic materials with high cellular toxicity. The Hg2+ ions can accumulate in the human body through the food chain and cause serious and permanent damage to the brain with both acute and chronic toxicity. According to the US Environment Protection Agency (EPA) guidelines, Hg2+ ions must be at concentrations below 1 ng/ml (10 nM) in drinking water. If the Hg2+ ions are higher than 2.5 ng/ml in serum, that will bring mercury poisoning. The traditional testing for Hg2+ ions includes atomic absorption, atomic fluorescence, and inductively coupled plasma mass spectrometry. These methods are usually coupled with gas chromatography, high-performance liquid chromatography, and capillary electrophoresis. However, these instrument-based techniques are rather complicated, time-consuming, costly, and unsuitable for online and portable use. An ultrasensitive and selective detection of mercury (II) in serum was investigated using a laser scanning confocal imaging-surface plasmon resonance system (LSCI-SPR). The detection limit was as low as 0.01 ng/ml for Hg2+ ions in fetal calf serum and that is lower than that was required Hg2+ ions must be at concentrations below 1 ng/ml by the US Environment Protection Agency (EPA) guidelines. This sensor was designed on a T-rich, single-stranded DNA (ssDNA)-modified gold film, which can be individually manipulated using specific T-Hg2+-T complex formation. The quenching intensity of the fluorescence images for rhodamine-labeled ssDNA fitted well with the changes in SPR. The changes varied with the Hg2+ ion concentration, which is unaffected by the presence of other metal ions. A good liner relation was got with the coefficients of 0.9116 in 30% fetal calf serums with the linear part over a range of 0.01 ng/ml to10 ng/ml.

  13. Dual-source parallel radiofrequency excitation ACR phantom magnetic resonance imaging at 3 T: Assessment of the effect of image quality on high-contrast spatial resolution, percent signal ghosting, and low-contrast object detectability in comparison with conventional single-source transmission

    NASA Astrophysics Data System (ADS)

    Lee, Kyung-Bae; Park, Yong-Sung; Choe, Bo-Young

    2013-10-01

    The purpose of the present study was to assess dual-source parallel radiofrequency (RF) excitation American College of Radiology (ACR) phantom magnetic resonance (MR) imaging at 3T compared with conventional single-source RF transmission and compared with the standard ACR MRI phantom test. We used a 3T MR scanner equipped with dual-source parallel RF excitation and an 8-channel head phased array coil. We employed T1- and T2-weighted fast spin echo (FSE) pulse sequences for an assessment of the impact of image quality on high-contrast spatial resolution, percent signal ghosting and low-contrast object detectability following the ACR MRI quality control (QC) manual. With geometric accuracy and identical slice locations, dual RFs using dual-source parallel RF excitation MR showed an advantage over single RF using dual-source parallel RF excitation MR and conventional MR in terms of high-contrast spatial resolution (p < 0.010), percent signal ghosting (p < 0.010), and low-contrast object detectability (p < 0.010). The quality of the image from the dual-source parallel RF excitation MR equipment was superior to that of the image from conventional MR equipment for the ACR phantom. We need to pursue dual-source parallel RF excitation MR studies involving various clinical cases.

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

    NASA Astrophysics Data System (ADS)

    Herrera, Sheryl Lyn

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

  15. 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.

  16. Magnetic resonance imaging of clays: swelling, sedimentation, dissolution

    NASA Astrophysics Data System (ADS)

    Dvinskikh, Sergey; Furo, Istvan

    2010-05-01

    While most magnetic resonance imaging (MRI) applications concern medical research, there is a rapidly increasing number of MRI studies in the field of environmental science and technology. In this presentation, MRI will be introduced from the latter perspective. While many processes in these areas are similar to those addressed in medical applications of MRI, parameters and experimental implementations are often quite different and, in many respects, far more demanding. This hinders direct transfer of existing methods developed for biomedical research, especially when facing the challenging task of obtaining spatially resolved quantitative information. In MRI investigation of soils, clays, and rocks, mainly water signal is detected, similarly to MRI of biological and medical samples. However, a strong variation of water mobility and a wide spread of water spin relaxation properties in these materials make it difficult to use standard MRI approaches. Other significant limitations can be identified as following: T2 relaxation and probe dead time effects; molecular diffusion artifacts; varying dielectric losses and induced currents in conductive samples; limited dynamic range; blurring artifacts accompanying drive for increasing sensitivity and/or imaging speed. Despite these limitations, by combining MRI techniques developed for solid and liquid states and using independent information on relaxation properties of water, interacting with the material of interest, true images of distributions of both water, material and molecular properties in a wide range of concentrations can be obtained. Examples of MRI application will be given in the areas of soil and mineral research where understanding water transport and erosion processes is one of the key challenges. Efforts in developing and adapting MRI approaches to study these kinds of systems will be outlined as well. Extensive studies of clay/water interaction have been carried out in order to provide a quantitative

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

    PubMed

    Driessen, Mieke M P; Breur, Johannes M P J; Budde, Ricardo P J; van Oorschot, Joep W M; van Kimmenade, Roland R J; Sieswerda, Gertjan Tj; Meijboom, Folkert J; Leiner, Tim

    2015-01-01

    Due to advances in cardiac surgery, survival of patients with congenital heart disease has increased considerably during the past decades. Many of these patients require repeated cardiovascular magnetic resonance imaging to assess cardiac anatomy and function. In the past decade, technological advances have enabled faster and more robust cardiovascular magnetic resonance with improved image quality and spatial as well as temporal resolution. This review aims to provide an overview of advances in cardiovascular magnetic resonance hardware and acquisition techniques relevant to both pediatric and adult patients with congenital heart disease and discusses the techniques used to assess function, anatomy, flow and tissue characterization. PMID:25552386

  18. 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.

  19. Protein-Peptide Arrays for Detection of Specific Anti-Hepatitis D Virus (HDV) Genotype 1, 6, and 8 Antibodies among HDV-Infected Patients by Surface Plasmon Resonance Imaging

    PubMed Central

    Villiers, Marie-Bernadette; Cortay, Jean-Claude; Cortès, Sandra; Bloquel, Bénédicte; Brichler, Ségolène; Brakha, Carine; Kay, Alan; Falah, Nisrine; Zoulim, Fabien; Marquette, Christophe

    2015-01-01

    Liver diseases linked to hepatitis B-hepatitis D virus co- or superinfections are more severe than those during hepatitis B virus (HBV) monoinfection. The diagnosis of hepatitis D virus (HDV) infection therefore remains crucial in monitoring patients but is often overlooked. To integrate HDV markers into high-throughput viral hepatitis diagnostics, we studied the binding of anti-HDV antibodies (Abs) using surface plasmon resonance imaging (SPRi). We focused on the ubiquitous HDV genotype 1 (HDV1) and the more uncommon African-HDV6 and HDV8 genotypes to define an array with recombinant proteins or peptides. Full-length and truncated small hepatitis D antigen (S-HDAg) recombinant proteins of HDV genotype 1 (HDV1) and 11 HDV peptides of HDV1, 6, and 8, representing various portions of the delta antigen were grafted onto biochips, allowing SPRi measurements to be made. Sixteen to 17 serum samples from patients infected with different HDV genotypes were injected onto protein and peptide chips. In all, Abs against HDV proteins and/or peptides were detected in 16 out of 17 infected patients (94.12%), although the amplitude of the SPR signal varied. The amino-terminal part of the protein was poorly immunogenic, while epitope 65-80, exposed on the viral ribonucleoprotein, may be immunodominant, as 9 patient samples led to a specific SPR signal on peptide 65 type 1 (65#1), independently of the infecting genotype. In this pilot study, we confirmed that HDV infection screening based on the reactivity of patient Abs against carefully chosen HDV peptides and/or proteins can be included in a syndrome-based viral hepatitis diagnostic assay. The preliminary results indicated that SPRi studying direct physical HDAg–anti-HDV Ab interactions was more convenient using linear peptide epitopes than full-length S-HDAg proteins, due to the regeneration process, and may represent an innovative approach for a hepatitis syndrome–viral etiology-exploring array. PMID:25631795

  20. Nonlinear mechanical resonators for ultra-sensitive mass detection

    SciTech Connect

    Datskos, Panos G; Lavrik, Nickolay V

    2014-01-01

    The fundamental sensitivity limit of an appropriately scaled down mechanical resonator can approach one atomic mass unit when only thermal noise is present in the system. However, operation of such nanoscale mechanical resonators is very challenging due to minuteness of their oscillation amplitudes and presence of multiple noise sources in real experimental environments. In order to surmount these challenges, we use microscale cantilever resonators driven to large amplitudes, far beyond their nonlinear instability onset. Our experiments show that such a nonlinear cantilever resonator, described analytically as a Duffing oscillator, has mass sensing performance comparable to that of much smaller resonators operating in a linear regime. We demonstrate femtogram level mass sensing that relies on a bifurcation point tracking that does not require any complex readout means. Our approaches enable straightforward detection of mass changes that are near the fundamental limit imposed by thermo-mechanical fluctuations.

  1. The diagnostic value of magnetic resonance imaging in non-traumatic osteonecrosis of the femoral head

    SciTech Connect

    Hauzeur, J.P.; Pasteels, J.L.; Schoutens, A.; Hinsenkamp, M.; Appelboom, T.; Chochrad, I.; Perlmutter, N.

    1989-06-01

    To assess the effectiveness of nuclear magnetic-resonance imaging in the detection of osteonecrosis of the femoral head, we studied the cases of twenty-five patients (forty-nine hips) in whom necrosis of the femoral head was suspected on the basis of plain radiographs, computed tomographic scans, radionuclide bone scans, and magnetic resonance-imaging scans. The results of these investigations were compared, for all except one patient, with the pathological findings of transtrochanteric core biopsies of the femoral head and neck of both hips. Of the forty-nine hips, thirty-three had histological proof of osteonecrosis. Twenty-two (67 per cent) of these hips showed definite necrosis on the plain radiographs; eighteen (62 per cent), on the twenty-nine available computed tomographic scans; twenty-four (77 per cent), on the thirty-one available radionuclide bone scans; and all of the hips, on the magnetic resonance-imaging studies. In six additional hips, there were histological changes (marrow necrosis, edema, hemorrhage, and fibrosis) in the medullary spaces without detectable osteonecrosis. The plain radiographs and computed tomographic scans of these six hips were normal except for the computed tomographic scan of one, and the radionuclide uptake on bone-scanning was abnormal in four of the six, as were the magnetic resonance-imaging studies. In the two hips that had normal magnetic resonance-imaging studies, the biopsies showed only destruction of fat cells in the medullary spaces, with no edema or fibroblastic reaction.

  2. Plasmon resonant particles for biological detection.

    PubMed

    Schultz, David A

    2003-02-01

    Several recent advances in the optical observation, fabrication, and bioconjugation of nanometer-sized gold or silver colloids have produced a robust new class of label. These plasmon resonant particle (PRP) conjugates have several important advantages: they are ultra-bright, so the light scattered from the individual particles can be viewed using a simple optical microscope system with a white light illumination source; they do not photo-bleach; PRPs can be prepared that preferentially scatter light of a chosen color; and it is possible to prepare bioconjugated PRPs that are stable in solution. These properties, and the automation of PRP identification, discrimination, and counting, have enabled the development of ultrasensitive, multicolor, and multiplex applications in the life science field. PMID:12565997

  3. Magnetic resonance imaging of congenital heart disease

    SciTech Connect

    Fletcher, B.D.; Jacobstein, M.D.

    1988-01-01

    Focusing primarily on MR imaging of the heart, this book covers other diagnostic imaging modalities as well. The authors review new technologies and diagnostic procedures pertinent to congenital heat disease and present each congenital heat abnormality as a separate entity.

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

    PubMed Central

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

    2015-01-01

    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

  5. 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

  6. Clear Depiction of Inflammatory Abdominal Aortic Aneurysm with Diffusion-Weighted Magnetic Resonance Imaging

    SciTech Connect

    Orta Kilickesmez, Kadriye; Kilickesmez, Ozgur

    2010-04-15

    We report the case of an inflammatory abdominal aortic aneurysm incidentally detected clearly with diffusion-weighted magnetic resonance imaging (DW-MRI) during the examination of a patient with myelofibrosis with myeloid metaplasia that later converted to acute myeloid leukemia. DW-MRI revealed a hyperintense halo surrounding the abdominal aorta with aneurysmatic dilatation, establishing the diagnosis.

  7. Unique pattern of late gadolinium enhancement on cardiac magnetic resonance imaging in Duchenne muscular dystrophy.

    PubMed

    Ganigara, Madhusudan; Sharma, Bharti; Komalla, Ravi Babu; Vyas, Suman Y; Mannam, Gopichand; Rao, Nitin Krishna

    2016-01-01

    Cardiomyopathy is an important cause of morbidity and mortality in patients with Duchenne muscular dystrophy (DMD). Early recognition of myocardial involvement and initiation of therapy are important for improved outcomes. Cardiac magnetic resonance imaging (CMR) is a sensitive tool in early detection of myocardial fibrosis in these children. PMID:27212861

  8. Unique pattern of late gadolinium enhancement on cardiac magnetic resonance imaging in Duchenne muscular dystrophy

    PubMed Central

    Ganigara, Madhusudan; Sharma, Bharti; Komalla, Ravi Babu; Vyas, Suman Y.; Mannam, Gopichand; Rao, Nitin Krishna

    2016-01-01

    Cardiomyopathy is an important cause of morbidity and mortality in patients with Duchenne muscular dystrophy (DMD). Early recognition of myocardial involvement and initiation of therapy are important for improved outcomes. Cardiac magnetic resonance imaging (CMR) is a sensitive tool in early detection of myocardial fibrosis in these children. PMID:27212861

  9. Travelling wave magnetic resonance imaging at 3 T

    NASA Astrophysics Data System (ADS)

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

    2013-08-01

    Waveguides have been successfully used to generate magnetic resonance images at 7 T with whole-body systems. The bore diameter limits the magnetic resonance signal transmitted because its specific cut-off frequency is greater than the majority of resonant frequencies in magnetic resonance imaging and spectroscopy. This restriction can be overcome by using a parallel-plate waveguide whose cut-off frequency is zero for the transverse electromagnetic modes and it can propagate any frequency. To study the potential benefits of travelling-wave excitation for whole-body imaging at 3 T, we compare numerical simulations of the principal mode propagation for a parallel-plate waveguide filled with a cylindrical phantom and two surface coils for all simulations at 1.5 T, 3 T, 4.7, 7 T, and 9.4 T. The principal mode shows very little variation of the field magnitude along the propagation direction at 3 T when compared to other higher resonant frequencies. Unlike the standard method for travelling-wave magnetic resonance imaging, a parallel-plate waveguide prototype was built and used together with a whole-body birdcage coil for signal transmission and a pair of circular coils for reception. Experimental B1 mapping was computed to investigate the feasibility of this approach and, the point spread function method was used to measure the imager performance. Human leg images were acquired to experimentally validate this approach. The numerical magnetic field and specific absorption rate of a simulated leg were computed and results are within the safety limits. The B1 mapping and point spread function results showed that it is possible to conduct travelling-wave imaging experiments with good imager performance. Human leg images were also obtained with the whole-body birdcage coil for comparison purposes. The simulated and in vivo travelling-wave results of the human leg correspond very well for the signal received. A similar image signal-to-noise ratio was observed for the

  10. Ultraviolet Resonant Raman Enhancements in the Detection of Explosives

    SciTech Connect

    Short Jr., Billy Joe

    2009-06-01

    Raman-based spectroscopy is potentially militarily useful for standoff detection of high explosives. Normal (non-resonance) and resonance Raman spectroscopies are both light scattering techniques that use a laser to measure the vibrational spectrum of a sample. In resonance Raman, the laser is tuned to match the wavelength of a strong electronic absorbance in the molecule of interest, whereas, in normal Raman the laser is not tuned to any strong electronic absorbance bands. The selection of appropriate excitation wavelengths in resonance Raman can result in a dramatic increase in the Raman scattering efficiency of select band(s) associated with the electronic transition. Other than the excitation wavelength, however, resonance Raman is performed experimentally the same as normal Raman. In these studies, normal and resonance Raman spectral signatures of select solid high explosive (HE) samples and explosive precursors were collected at 785 nm, 244 nm and 229 nm. Solutions of PETN, TNT, and explosive precursors (DNT & PNT) in acetonitrile solvent as an internal Raman standard were quantitatively evaluated using ultraviolet resonance Raman (UVRR) microscopy and normal Raman spectroscopy as a function of power and select excitation wavelengths. Use of an internal standard allowed resonance enhancements to be estimated at 229 nm and 244 nm. Investigations demonstrated that UVRR provided ~2000-fold enhancement at 244 nm and ~800-fold improvement at 229 nm while PETN showed a maximum of ~25-fold at 244 nm and ~190-fold enhancement at 229 nm solely from resonance effects when compared to normal Raman measurements. In addition to the observed resonance enhancements, additional Raman signal enhancements are obtained with ultraviolet excitation (i.e., Raman scattering scales as !4 for measurements based on scattered photons). A model, based partly on the resonance Raman enhancement results for HE solutions, is presented for estimating Raman enhancements for solid HE samples.

  11. Anicteric early bile duct carcinoma detection with magnetic resonance cholangiopancreatography.

    PubMed

    Oshikiri, Taro; Morita, Takayuki; Fujita, Miyoshi; Miyasaka, Yuji; Senmaru, Naoto; Yamada, Hidehisa; Kondo, Satoshi; Katoh, Hiroyuki

    2005-01-01

    The poor prognosis of extrahepatic bile duct carcinoma makes early detection and diagnosis essential for positive patient outcomes. We describe 2 cases of jaundice-free early extrahepatic bile duct carcinoma detected by magnetic resonance cholangiopancreatography. Extrahepatic bile duct carcinoma was discovered incidentally in patient 1 by magnetic resonance cholangiopancreatography during evaluation of a gallbladder stone. In patient 2, extrahepatic bile duct carcinoma was found during a routine health maintenance exam. Both patients underwent radical surgical intervention. Both patient 1 and 2 have remained in good health for over one year, 3.5 and one year, respectively, and have not exhibited any signs or symptoms of relapse or cancer recurrence. Based on these cases, it appears that magnetic resonance cholangiopancreatography can play a significant role in the early detection of extrahepatic bile duct carcinoma and improve disease prognosis. PMID:15816438

  12. Detection of Majorana fermions by Fano resonance in hybrid nanostructures

    NASA Astrophysics Data System (ADS)

    Xia, Jun-Jie; Duan, Su-Qing; Zhang, Wei

    2015-05-01

    The realization and detection of Majorana fermions in condensed matter systems are of considerable importance and interest. We propose a scheme to detect the Majorana fermions by Fano resonance in hybrid nanostructures made of semiconductor quantum dots and quantum wire in proximity to superconductor. Through detailed theoretical studies of the transport properties of our hybrid nanostructures based on the non-equilibrium Green's function technique and the equation of motion approach, it is found that the Fano resonance in the current response due to the interference among different transmission paths may give clear signature of the existence of Majorana modes. Moreover, we have found a peculiar relationship between the Fano factor q and the Majorana bound state coupling strength/the length of nanowire, which can be used for a design of an electronic nanoruler. Our method of detection of Majorana fermions based on Fano resonance is related to the global conductance profile, thus is robust to perturbations.

  13. Detection of Majorana fermions by Fano resonance in hybrid nanostructures.

    PubMed

    Xia, Jun-Jie; Duan, Su-Qing; Zhang, Wei

    2015-01-01

    The realization and detection of Majorana fermions in condensed matter systems are of considerable importance and interest. We propose a scheme to detect the Majorana fermions by Fano resonance in hybrid nanostructures made of semiconductor quantum dots and quantum wire in proximity to superconductor. Through detailed theoretical studies of the transport properties of our hybrid nanostructures based on the non-equilibrium Green's function technique and the equation of motion approach, it is found that the Fano resonance in the current response due to the interference among different transmission paths may give clear signature of the existence of Majorana modes. Moreover, we have found a peculiar relationship between the Fano factor q and the Majorana bound state coupling strength/the length of nanowire, which can be used for a design of an electronic nanoruler. Our method of detection of Majorana fermions based on Fano resonance is related to the global conductance profile, thus is robust to perturbations. PMID:26034416

  14. 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…

  15. Voriconazole-related periostitis presenting on magnetic resonance imaging.

    PubMed

    Davis, Derik L

    2015-01-01

    Painful periostitis is a complication of long-term antifungal therapy with voriconazole. A high clinical suspicion coupled with imaging and laboratory assessment is useful to establish the diagnosis. Prompt discontinuance of voriconazole typically results in the resolution of symptoms and signs. This report describes the presentation of voriconazole-related periostitis on magnetic resonance imaging. PMID:26136804

  16. Voriconazole-related periostitis presenting on magnetic resonance imaging

    PubMed Central

    Davis, Derik L.

    2015-01-01

    Summary Painful periostitis is a complication of long-term antifungal therapy with voriconazole. A high clinical suspicion coupled with imaging and laboratory assessment is useful to establish the diagnosis. Prompt discontinuance of voriconazole typically results in the resolution of symptoms and signs. This report describes the presentation of voriconazole-related periostitis on magnetic resonance imaging. PMID:26136804

  17. Estimating the size of myocardial infarction by magnetic resonance imaging.

    PubMed Central

    Turnbull, L W; Ridgway, J P; Nicoll, J J; Bell, D; Best, J J; Muir, A L

    1991-01-01

    OBJECTIVE--To develop a method to measure myocardial infarct size by magnetic resonance imaging and to compare the results with pyrophosphate scanning by single photon emission computed tomography. DESIGN--All patients underwent magnetic resonance imaging and pyrophosphate scanning 5-7 days after the onset of symptoms. Both measurements of infarct size were compared with the release of creatine kinase MB and with ventricular performance estimated by radionuclide ventriculography. PATIENTS--19 patients (age 40-68 years) who had sustained their first uncomplicated myocardial infarction and who had not been treated with thrombolytic therapy. RESULTS--The site of infarction was clearly shown by both imaging techniques and was identical in each patient. The volume of infarcted tissue measured by magnetic resonance imaging agreed well with the infarct size measured by single photon emission tomography (mean difference 2.7 cm3). Correlations of both imaging techniques with the release of creatine kinase MB were best when total release rather than peak release was used. Both imaging techniques correlated closely with the subsequent ventricular performance. CONCLUSIONS--Magnetic resonance imaging after acute infarction allows measurement of infarct size and this may prove useful in assessing new treatments designed to salvage myocardium. Images PMID:1836135

  18. Fabrication of vascular replicas from magnetic resonance images.

    PubMed

    Friedman, M H; Kuban, B D; Schmalbrock, P; Smith, K; Altan, T

    1995-08-01

    Image processing and Computer Numerical Controlled (CNC) machining techniques have been used to prepare a large-than-life investment cast of an aortic bifurcation from magnetic resonance images of a replica of the vessel. The technique will facilitate experimental studies of vascular fluid dynamics and permit the in vitro reproduction of flows in living subjects. PMID:8618391

  19. A Smart Phone Image Database for Single Image Recapture Detection

    NASA Astrophysics Data System (ADS)

    Gao, Xinting; Qiu, Bo; Shen, Jingjing; Ng, Tian-Tsong; Shi, Yun Qing

    Image recapture detection (IRD) is to distinguish real-scene images from the recaptured ones. Being able to detect recaptured images, a single image based counter-measure for rebroadcast attack on a face authentication system becomes feasible. Being able to detect recaptured images, general object recognition can differentiate the objects on a poster from the real ones, so that robot vision is more intelligent. Being able to detect recaptured images, composite image can be detected when recapture is used as a tool to cover the composite clues. As more and more methods have been proposed for IRD, an open database is indispensable to provide a common platform to compare the performance of different methods and to expedite further research and collaboration in the field of IRD.

  20. 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

  1. 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.

  2. Superparamagnetic nanoparticles for enhanced magnetic resonance and multimodal imaging

    NASA Astrophysics Data System (ADS)

    Sikma, Elise Ann Schultz

    Magnetic resonance imaging (MRI) is a powerful tool for noninvasive tomographic imaging of biological systems with high spatial and temporal resolution. Superparamagnetic (SPM) nanoparticles have emerged as highly effective MR contrast agents due to their biocompatibility, ease of surface modification and magnetic properties. Conventional nanoparticle contrast agents suffer from difficult synthetic reproducibility, polydisperse sizes and weak magnetism. Numerous synthetic techniques and nanoparticle formulations have been developed to overcome these barriers. However, there are still major limitations in the development of new nanoparticle-based probes for MR and multimodal imaging including low signal amplification and absence of biochemical reporters. To address these issues, a set of multimodal (T2/optical) and dual contrast (T1/T2) nanoparticle probes has been developed. Their unique magnetic properties and imaging capabilities were thoroughly explored. An enzyme-activatable contrast agent is currently being developed as an innovative means for early in vivo detection of cancer at the cellular level. Multimodal probes function by combining the strengths of multiple imaging techniques into a single agent. Co-registration of data obtained by multiple imaging modalities validates the data, enhancing its quality and reliability. A series of T2/optical probes were successfully synthesized by attachment of a fluorescent dye to the surface of different types of nanoparticles. The multimodal nanoparticles generated sufficient MR and fluorescence signal to image transplanted islets in vivo. Dual contrast T1/T2 imaging probes were designed to overcome disadvantages inherent in the individual T1 and T2 components. A class of T1/T2 agents was developed consisting of a gadolinium (III) complex (DTPA chelate or DO3A macrocycle) conjugated to a biocompatible silica-coated metal oxide nanoparticle through a disulfide linker. The disulfide linker has the ability to be reduced

  3. Diagnosis of brainstem abscess in the cerebritis stage by magnetic resonance imaging--case report.

    PubMed

    Adachi, J; Uki, J; Kazumoto, K; Takeda, F

    1995-07-01

    A 52-year-old male presented with a brainstem abscess manifesting as high fever, diplopia, and left hemiparesis. Magnetic resonance (MR) imaging with gadolinium diethylenetriamine pentaacetic acid showed the lesion as a ring-like enhanced mass consisting of a necrotic center with surrounding edema, whereas postcontrast computed tomography revealed no such confirmatory findings. He was treated with antibiotics as the lesion had been detected in the acute cerebritis stage. Serial MR images showed that the lesion decreased remarkably in size. MR imaging can detect brain abscess in the earliest inflammatory stage. PMID:7477693

  4. 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…

  5. Plasmon resonance enhanced mechanical detection of ligand binding

    SciTech Connect

    Ariyaratne, Amila; Zocchi, Giovanni

    2015-01-05

    Small molecule binding to the active site of enzymes typically modifies the mechanical stiffness of the enzyme. We exploit this effect, in a setup which combines nano-mechanics and surface plasmon resonance (SPR) enhanced optics, for the label free detection of ligand binding to an enzyme. The large dynamic range of the signal allows to easily obtain binding curves for small ligands, in contrast to traditional SPR methods which rely on small changes in index of refraction. Enzyme mechanics, assessed by nano-rheology, thus emerges as an alternative to electronic and spin resonances, assessed by traditional spectroscopies, for detecting ligand binding.

  6. High resolution in-operando microimaging of solar cells with pulsed electrically-detected magnetic resonance.

    PubMed

    Katz, Itai; Fehr, Matthias; Schnegg, Alexander; Lips, Klaus; Blank, Aharon

    2015-02-01

    The in-operando detection and high resolution spatial imaging of paramagnetic defects, impurities, and states becomes increasingly important for understanding loss mechanisms in solid-state electronic devices. Electron spin resonance (ESR), commonly employed for observing these species, cannot meet this challenge since it suffers from limited sensitivity and spatial resolution. An alternative and much more sensitive method, called electrically-detected magnetic resonance (EDMR), detects the species through their magnetic fingerprint, which can be traced in the device's electrical current. However, until now it could not obtain high resolution images in operating electronic devices. In this work, the first spatially-resolved electrically-detected magnetic resonance images (EDMRI) of paramagnetic states in an operating real-world electronic device are provided. The presented method is based on a novel microwave pulse sequence allowing for the coherent electrical detection of spin echoes in combination with powerful pulsed magnetic-field gradients. The applicability of the method is demonstrated on a device-grade 1-μm-thick amorphous silicon (a-Si:H) solar cell and an identical device that was degraded locally by an electron beam. The degraded areas with increased concentrations of paramagnetic defects lead to a local increase in recombination that is mapped by EDMRI with ∼20-μm-scale pixel resolution. The novel approach presented here can be widely used in the nondestructive in-operando three-dimensional characterization of solid-state electronic devices with a resolution potential of less than 100 nm. PMID:25557860

  7. High resolution in-operando microimaging of solar cells with pulsed electrically-detected magnetic resonance

    NASA Astrophysics Data System (ADS)

    Katz, Itai; Fehr, Matthias; Schnegg, Alexander; Lips, Klaus; Blank, Aharon

    2015-02-01

    The in-operando detection and high resolution spatial imaging of paramagnetic defects, impurities, and states becomes increasingly important for understanding loss mechanisms in solid-state electronic devices. Electron spin resonance (ESR), commonly employed for observing these species, cannot meet this challenge since it suffers from limited sensitivity and spatial resolution. An alternative and much more sensitive method, called electrically-detected magnetic resonance (EDMR), detects the species through their magnetic fingerprint, which can be traced in the device's electrical current. However, until now it could not obtain high resolution images in operating electronic devices. In this work, the first spatially-resolved electrically-detected magnetic resonance images (EDMRI) of paramagnetic states in an operating real-world electronic device are provided. The presented method is based on a novel microwave pulse sequence allowing for the coherent electrical detection of spin echoes in combination with powerful pulsed magnetic-field gradients. The applicability of the method is demonstrated on a device-grade 1-μm-thick amorphous silicon (a-Si:H) solar cell and an identical device that was degraded locally by an electron beam. The degraded areas with increased concentrations of paramagnetic defects lead to a local increase in recombination that is mapped by EDMRI with ∼20-μm-scale pixel resolution. The novel approach presented here can be widely used in the nondestructive in-operando three-dimensional characterization of solid-state electronic devices with a resolution potential of less than 100 nm.

  8. A Quadricuspid Aortic Valve as Seen by Cardiac Magnetic Resonance Imaging.

    PubMed

    Jones, James; Liotta, Robert; Hood, Maureen; Bustamante, Alexander

    2016-09-01

    We report a case of a 35-year-old active duty male with a rare quadricuspid aortic valve identified via transthoracic echocardiography following the detection of an incidental grade I/VI diastolic murmur. Further characterization of the anatomical findings and aortic valve flow dynamics were evaluated with cardiac magnetic resonance imaging. Accurate assessment of the various valve morphologies is essential, as it guides surgical treatment options to correct the defect. Our case highlights the complimentary role of cardiac magnetic resonance imaging in defining the anatomy and functional consequences of a quadricuspid aortic valve. PMID:27612379

  9. Paramagnetic and ferromagnetic resonance imaging with a tip-on-cantilever magnetic resonance force microscope

    NASA Astrophysics Data System (ADS)

    Wago, K.; Botkin, D.; Yannoni, C. S.; Rugar, D.

    1998-05-01

    A magnetic resonance force microscope with a "tip-on-cantilever" configuration was used to compare imaging characteristics of paramagnetic and ferromagnetic samples. Three-dimensional electron paramagnetic resonance (EPR) imaging of diphenylpicrylhydrazil (DPPH) particles was accomplished by scanning the sample in two dimensions while stepping an external field. The EPR force map showed broad response reflecting the size and shape of the sample, allowing a three-dimensional real-space magnetization image to be successfully reconstructed. In contrast to the EPR case, ferromagnetic resonance imaging of a micron-scale yttrium iron garnet sample showed no significant line broadening despite the strong field gradient (˜10 G/μm). Two-dimensional force maps revealed spatial dependence of magnetostatic and magnetoelastic modes.

  10. Comparison of Paramagnetic and Ferromagnetic Resonance Imaging with an Improved Magnetic Resonance Force Microscope

    NASA Astrophysics Data System (ADS)

    Wago, K.; Botkin, D.; Yannoni, C. S.; Rugar, D.

    1998-03-01

    A magnetic resonance force microscope with an improved ``tip-on-cantilever'' configuration was used to compare imaging characteristics of paramagnetic and ferromagnetic samples. Three-dimensional electron paramagnetic resonance (EPR) imaging of diphenylpicrylhydrazil (DPPH) particles was accomplished by scanning the sample in two dimensions while stepping an external field. The EPR force map showed broad response reflecting the size and shape of the sample, allowing a three-dimensional real-space magnetization image to be successfully reconstructed. In contrast to the EPR case, ferromagnetic resonance (FMR) imaging of a micron-scale yttrium iron garnet (YIG) sample showed no significant line broadening despite the strong field gradient ( ~ 10 G/μm). Two-dimensional force maps revealed spatial dependence of magnetostatic and magnetoelastic modes.

  11. A sequential framework for image change detection.

    PubMed

    Lingg, Andrew J; Zelnio, Edmund; Garber, Fred; Rigling, Brian D

    2014-05-01

    We present a sequential framework for change detection. This framework allows us to use multiple images from reference and mission passes of a scene of interest in order to improve detection performance. It includes a change statistic that is easily updated when additional data becomes available. Detection performance using this statistic is predictable when the reference and image data are drawn from known distributions. We verify our performance prediction by simulation. Additionally, we show that detection performance improves with additional measurements on a set of synthetic aperture radar images and a set of visible images with unknown probability distributions. PMID:24818249

  12. Three-dimensional Magnetic Resonance Imaging of fossils across taxa

    NASA Astrophysics Data System (ADS)

    Mietchen, D.; Aberhan, M.; Manz, B.; Hampe, O.; Mohr, B.; Neumann, C.; Volke, F.

    2007-08-01

    The visibility of life forms in the fossil record is largely determined by the extent to which they were mineralised at the time of their death. In addition to mineral structures, many fossils nonetheless contain detectable amounts of residual water or organic molecules, the analysis of which has become an integral part of current palaeontological research. The methods available for this sort of investigations, though, typically require dissolution or ionisation of the fossil sample or parts thereof, which is an issue with rare taxa and outstanding materials like pathological or type specimens. In such cases, non-destructive techniques could provide an interesting methodological alternative. While Computed Tomography has long been used to study palaeontological specimens, a number of complementary approaches have recently gained ground. These include Magnetic Resonance Imaging (MRI) which had previously been employed to obtain three-dimensional images of pathological belemnites non-invasively on the basis of intrinsic contrast. The present study was undertaken to investigate whether 1H MRI can likewise provide anatomical information about non-pathological belemnites and specimens of other fossil taxa. To this end, three-dimensional MR image series were acquired from intact non-pathological invertebrate, vertebrate and plant fossils. At routine voxel resolutions in the range of several dozens to some hundreds of micrometers, these images reveal a host of anatomical details and thus highlight the potential of MR techniques to effectively complement existing methodological approaches for palaeontological investigations in a wide range of taxa. As for the origin of the MR signal, relaxation and diffusion measurements as well as 1H and 13C MR spectra acquired from a belemnite suggest intracrystalline water or hydroxyl groups, rather than organic residues.

  13. Three-dimensional Magnetic Resonance Imaging of fossils across taxa

    NASA Astrophysics Data System (ADS)

    Mietchen, D.; Aberhan, M.; Manz, B.; Hampe, O.; Mohr, B.; Neumann, C.; Volke, F.

    2008-01-01

    The frequency of life forms in the fossil record is largely determined by the extent to which they were mineralised at the time of their death. In addition to mineral structures, many fossils nonetheless contain detectable amounts of residual water or organic molecules, the analysis of which has become an integral part of current palaeontological research. The methods available for this sort of investigations, though, typically require dissolution or ionisation of the fossil sample or parts thereof, which is an issue with rare taxa and outstanding materials like pathological or type specimens. In such cases, non-destructive techniques could provide a valuable methodological alternative. While Computed Tomography has long been used to study palaeontological specimens, a number of complementary approaches have recently gained ground. These include Magnetic Resonance Imaging (MRI) which had previously been employed to obtain three-dimensional images of pathological belemnites non-invasively on the basis of intrinsic contrast. The present study was undertaken to investigate whether 1H MRI can likewise provide anatomical information about non-pathological belemnites and specimens of other fossil taxa. To this end, three-dimensional MR image series were acquired from intact non-pathological invertebrate, vertebrate and plant fossils. At routine voxel resolutions in the range of several dozens to some hundreds of micrometers, these images reveal a host of anatomical details and thus highlight the potential of MR techniques to effectively complement existing methodological approaches for palaeontological investigations in a wide range of taxa. As for the origin of the MR signal, relaxation and diffusion measurements as well as 1H and 13C MR spectra acquired from a belemnite suggest intracrystalline water or hydroxyl groups, rather than organic residues.

  14. Multiprocessing DSP imaging system and instrumentation design for magnetic resonance spectroscopy/imaging

    NASA Astrophysics Data System (ADS)

    Bukhari, S. M. H.

    1998-09-01

    The architectural design of an image processing system and its instrumentation is elucidated here in this presentation, based upon the multiprocessing TMS320C82 DSP processors, working under a specially-defined MAEVRISC-DSP (Multidimensional Application-Embedded Vector RISC-DSP) architecture, that blends high-precision and high- performance (120 MFLOPS digital and 100 MSPS analog) data acquisition with efficient signal processing architecture design and prevalent Tagged MRI pulse sequence algorithms, specifically optimized for the medical imaging applications of Magnetic Resonance Spectroscopy and Imaging (MRI) tomography, while at the same time giving a low-cost alternative to extremely-expensive MRI systems. Alongside the system definition, the design of a new magneto-optical instrumentation is also presented, named SQUID and LPDA- based Field Equalization and Susceptibility Detection sensing, which works upon the recently-defined Tunneling Photon Resonance effect, mainly devised with non-ionizing human brain tumor diagnosis and localization in perspective, whose brief account is highlighted here.

  15. Magnetic Resonance Imaging of the Central Nervous System—An Update

    PubMed Central

    Brant-Zawadzki, Michael; Norman, David; Newton, T. Hans; Kucharczyk, Walter

    1985-01-01

    Magnetic resonance imaging has developed rapidly and now has superior ability to detect and to characterize disease in the central nervous system without any significant biologic hazard. It is becoming the screening method of choice in the diagnosis of neoplasm, ischemia, hemorrhage, infection and degenerative and demyelinating diseases involving the central nervous system. ImagesFigure 1.Figure 2.Figure 3.Figure 4.Figure 5.Figure 6.Figure 7.Figure 8.Figure 9. PMID:3976220

  16. 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.

  17. Magnetic resonance imaging of immiscible fluid displacement in porous media

    NASA Astrophysics Data System (ADS)

    Chen, Jing-Den; Dias, Madalena M.; Patz, Samuel; Schwartz, Lawrence M.

    1988-09-01

    Magnetic resonance imaging is used to study oil and water invasion in a model porous medium. Images taken normal to the flow direction are processed to give both the oil saturation and the fractal character of the oil distribution. These images reveal qualitative differences between the cases of invasion by the wetting (water) and nonwetting (oil) fluids. We have also found large saturation fluctuations in the residual oil state in which the oil consists entirely of disconnected blobs.

  18. Resonance ionization detection of combustion radicals

    SciTech Connect

    Cool, T.A.

    1993-12-01

    Fundamental research on the combustion of halogenated organic compounds with emphasis on reaction pathways leading to the formation of chlorinated aromatic compounds and the development of continuous emission monitoring methods will assist in DOE efforts in the management and disposal of hazardous chemical wastes. Selective laser ionization techniques are used in this laboratory for the measurement of concentration profiles of radical intermediates in the combustion of chlorinated hydrocarbon flames. A new ultrasensitive detection technique, made possible with the advent of tunable VUV laser sources, enables the selective near-threshold photoionization of all radical intermediates in premixed hydrocarbon and chlorinated hydrocarbon flames.

  19. Proton magnetic resonance imaging using a nitrogen-vacancy spin sensor.

    PubMed

    Rugar, D; Mamin, H J; Sherwood, M H; Kim, M; Rettner, C T; Ohno, K; Awschalom, D D

    2015-02-01

    Magnetic resonance imaging, with its ability to provide three-dimensional, elementally selective imaging without radiation damage, has had a revolutionary impact in many fields, especially medicine and the neurosciences. Although challenging, its extension to the nanometre scale could provide a powerful new tool for the nanosciences, especially if it can provide a means for non-destructively visualizing the full three-dimensional morphology of complex nanostructures, including biomolecules. To achieve this potential, innovative new detection strategies are required to overcome the severe sensitivity limitations of conventional inductive detection techniques. One successful example is magnetic resonance force microscopy, which has demonstrated three-dimensional imaging of proton NMR with resolution on the order of 10 nm, but with the requirement of operating at cryogenic temperatures. Nitrogen-vacancy (NV) centres in diamond offer an alternative detection strategy for nanoscale magnetic resonance imaging that is operable at room temperature. Here, we demonstrate two-dimensional imaging of (1)H NMR from a polymer test sample using a single NV centre in diamond as the sensor. The NV centre detects the oscillating magnetic field from precessing protons as the sample is scanned past the NV centre. A spatial resolution of ∼12 nm is shown, limited primarily by the scan resolution. PMID:25531089

  20. Proton magnetic resonance imaging using a nitrogen-vacancy spin sensor

    NASA Astrophysics Data System (ADS)

    Rugar, D.; Mamin, H. J.; Sherwood, M. H.; Kim, M.; Rettner, C. T.; Ohno, K.; Awschalom, D. D.

    2015-02-01

    Magnetic resonance imaging, with its ability to provide three-dimensional, elementally selective imaging without radiation damage, has had a revolutionary impact in many fields, especially medicine and the neurosciences. Although challenging, its extension to the nanometre scale could provide a powerful new tool for the nanosciences, especially if it can provide a means for non-destructively visualizing the full three-dimensional morphology of complex nanostructures, including biomolecules. To achieve this potential, innovative new detection strategies are required to overcome the severe sensitivity limitations of conventional inductive detection techniques. One successful example is magnetic resonance force microscopy, which has demonstrated three-dimensional imaging of proton NMR with resolution on the order of 10 nm, but with the requirement of operating at cryogenic temperatures. Nitrogen-vacancy (NV) centres in diamond offer an alternative detection strategy for nanoscale magnetic resonance imaging that is operable at room temperature. Here, we demonstrate two-dimensional imaging of 1H NMR from a polymer test sample using a single NV centre in diamond as the sensor. The NV centre detects the oscillating magnetic field from precessing protons as the sample is scanned past the NV centre. A spatial resolution of ˜12 nm is shown, limited primarily by the scan resolution.

  1. 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

  2. Active Nuclear Material Detection and Imaging

    SciTech Connect

    Daren Norman; James Jones; KevinHaskell; Peter E. Vanmier; Leon Forman

    2005-10-01

    An experimental evaluation has been conducted to assess the operational performance of a coded-aperture, thermal neutron imaging system and its detection and imaging capability for shielded nuclear material in pulsed photonuclear environments. This evaluation used an imaging system developed by Brookhaven National Laboratory. The active photonuclear environment was produced by an operationallyflexible, Idaho National Laboratory (INL) pulsed electron accelerator. The neutron environments were monitored using INL photonuclear neutron detectors. Results include experimental images, operational imaging system assessments and recommendations that would enhance nuclear material detection and imaging performance.

  3. Magnetic resonance imaging simulator: a teaching tool for radiology.

    PubMed

    Rundle, D; Kishore, S; Seshadri, S; Wehrli, F

    1990-11-01

    The increasing use of magnetic resonance imaging (MRI) as a clinical modality has put an enormous burden on medical institutions to cost effectively teach MRI scanning techniques to technologists and physicians. Since MRI scanner time is a scarce resource, it would be ideal if the teaching could be effectively performed off-line. In order to meet this goal, the radiology Department at the University of Pennsylvania has designed and developed a Magnetic Resonance Imaging Simulator. The simulator in its current implementation mimics the General Electric Signa (General Electric Magnetic Resonance Imaging System, Milwaukee, WI) scanner's user interface for image acquisition. The design is general enough to be applied to other MRI scanners. One unique feature of the simulator is its incorporation of an image-synthesis module that permits the user to derive images for any arbitrary combination of pulsing parameters for spin-echo, gradient-echo, and inversion recovery pulse sequences. These images are computed in 5 seconds. The development platform chosen is a standard Apple Macintosh II (Apple Computer, Inc, Cupertino, CA) computer with no specialized hardware peripherals. The user interface is implemented in HyperCard (Apple Computer Inc, Cupertino, CA). All other software development including synthesis and display functions are implemented under the Macintosh Programmer's Workshop 'C' environment. The scan parameters, demographics, and images are tracked using an Oracle (Oracle Corp, Redwood Shores, CA) data base. Images are currently stored on magnetic disk but could be stored on optical media with minimal effort. PMID:2085559

  4. 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.

  5. Detecting Copy Move Forgery In Digital Images

    NASA Astrophysics Data System (ADS)

    Gupta, Ashima; Saxena, Nisheeth; Vasistha, S. K.

    2012-03-01

    In today's world several image manipulation software's are available. Manipulation of digital images has become a serious problem nowadays. There are many areas like medical imaging, digital forensics, journalism, scientific publications, etc, where image forgery can be done very easily. To determine whether a digital image is original or doctored is a big challenge. To find the marks of tampering in a digital image is a challenging task. The detection methods can be very useful in image forensics which can be used as a proof for the authenticity of a digital image. In this paper we propose the method to detect region duplication forgery by dividing the image into overlapping block and then perform searching to find out the duplicated region in the image.

  6. Tissue oxygen saturation mapping with magnetic resonance imaging

    PubMed Central

    Christen, Thomas; Bouzat, Pierre; Pannetier, Nicolas; Coquery, Nicolas; Moisan, Anaïck; Lemasson, Benjamin; Thomas, Sébastien; Grillon, Emmanuelle; Detante, Olivier; Rémy, Chantal; Payen, Jean-François; Barbier, Emmanuel Luc

    2014-01-01

    A quantitative estimate of cerebral blood oxygen saturation is of critical importance in the investigation of cerebrovascular disease. While positron emission tomography can map in vivo the oxygen level in blood, it has limited availability and requires ionizing radiation. Magnetic resonance imaging (MRI) offers an alternative through the blood oxygen level-dependent contrast. Here, we describe an in vivo and non-invasive approach to map brain tissue oxygen saturation (StO2) with high spatial resolution. StO2 obtained with MRI correlated well with results from blood gas analyses for various oxygen and hematocrit challenges. In a stroke model, the hypoxic areas delineated in vivo by MRI spatially matched those observed ex vivo by pimonidazole staining. In a model of diffuse traumatic brain injury, MRI was able to detect even a reduction in StO2 that was too small to be detected by histology. In a F98 glioma model, MRI was able to map oxygenation heterogeneity. Thus, the MRI technique may improve our understanding of the pathophysiology of several brain diseases involving impaired oxygenation. PMID:25005878

  7. Adult Human Neurogenesis: From Microscopy to Magnetic Resonance Imaging

    PubMed Central

    Sierra, Amanda; Encinas, Juan M.; Maletic-Savatic, Mirjana

    2011-01-01

    Neural stem cells reside in well-defined areas of the adult human brain and are capable of generating new neurons throughout the life span. In rodents, it is well established that the new born neurons are involved in olfaction as well as in certain forms of memory and learning. In humans, the functional relevance of adult human neurogenesis is being investigated, in particular its implication in the etiopathology of a variety of brain disorders. Adult neurogenesis in the human brain was discovered by utilizing methodologies directly imported from the rodent research, such as immunohistological detection of proliferation and cell-type specific biomarkers in postmortem or biopsy tissue. However, in the vast majority of cases, these methods do not support longitudinal studies; thus, the capacity of the putative stem cells to form new neurons under different disease conditions cannot be tested. More recently, new technologies have been specifically developed for the detection and quantification of neural stem cells in the living human brain. These technologies rely on the use of magnetic resonance imaging, available in hospitals worldwide. Although they require further validation in rodents and primates, these new methods hold the potential to test the contribution of adult human neurogenesis to brain function in both health and disease. This review reports on the current knowledge on adult human neurogenesis. We first review the different methods available to assess human neurogenesis, both ex vivo and in vivo and then appraise the changes of adult neurogenesis in human diseases. PMID:21519376

  8. BI-RADS 3 for magnetic resonance imaging.

    PubMed

    Comstock, Christopher; Sung, Janice S

    2013-08-01

    A BI-RADS (Breast Imaging Reporting and Data System) 3, or probably benign, assessment is given in approximately 7% to 12% of breast magnetic resonance (MR) images. However, the imaging features of probably benign lesions on MR imaging have not been well defined. As with mammography and ultrasonography, a BI-RADS 3 assessment should be used only when there is a less than 2% likelihood of malignancy. The use of BI-RADS 3 for classically benign findings should be avoided. Certain masses, foci, and areas of nonmass enhancement may be categorized as probably benign on baseline MR imaging. PMID:23928245

  9. Study on multispectral imaging detection and recognition

    NASA Astrophysics Data System (ADS)

    Jun, Wang; Na, Ding; Gao, Jiaobo; Yu, Hu; Jun, Wu; Li, Junna; Zheng, Yawei; Fei, Gao; Sun, Kefeng

    2009-07-01

    Multispectral imaging detecting technology use target radiation character in spectral spatial distribution and relation between spectral and image to detect target and remote sensing measure. Its speciality is multi channel, narrow bandwidth, large amount of information, high accuracy. The ability of detecting target in environment of clutter, camouflage, concealment and beguilement is improved. At present, spectral imaging technology in the range of multispectral and hyperspectral develop greatly. The multispectral imaging equipment of unmanned aerial vehicle can be used in mine detection, information, surveillance and reconnaissance. Spectral imaging spectrometer operating in MWIR and LWIR has already been applied in the field of remote sensing and military in the advanced country. The paper presents the technology of multispectral imaging. It can enhance the reflectance, scatter and radiation character of the artificial targets among nature background. The targets among complex background and camouflage/stealth targets can be effectively identified. The experiment results and the data of spectral imaging is obtained.

  10. Single molecule spin resonance spectroscopy and imaging by diamond-sensor

    NASA Astrophysics Data System (ADS)

    Du, Jiangfeng

    Single-molecule magnetic resonance spectroscopy and imaging is one of the ultimate goals in magnetic resonance and will has great applications in a broad range of scientific areas, from life science to physics and chemistry. The spin of a single nitrogen vacancy (NV) center in diamond is a highly sensitive magnetic-field sensor, which has been proposed for detection of single molecules or nanoscale targets. We and co-workers have successfully obtained the first single-protein spin resonance spectroscopy under ambient conditions, high-resolution vector microwave imaging, and realized atomic-scale structure analysis of single nuclear-spin clusters in diamond. Moreover, we have tried to improve the quantum control technique and succeed to achieve fault-tolerant universal quantum gates. As the last part, I will briefly introduce our most recently work on single protein imaging in situ in cell.

  11. Simultaneous amplitude-contrast and phase-contrast surface plasmon resonance imaging by use of digital holography

    PubMed Central

    Li, Shiping; Zhong, Jingang

    2012-01-01

    The surface plasmon resonance imaging technique provides a tool that allows high-throughput analysis and real-time kinetic measurement. A simultaneous amplitude-contrast and phase-contrast surface plasmon resonance imaging method is presented. The amplitude-contrast and phase-contrast images are simultaneously obtained by use of digital holography. The detection sensitivity of amplitude-contrast imaging and phase-contrast imaging can compensate for each other. Thus, the detectable sample components may cover a wider range of refractive index values for the simultaneous amplitude-contrast and phase-contrast imaging method than for the phase-contrast imaging method or amplitude-contrast imaging method. A detailed description of the theory and an experiment of monitoring the evaporation process of a drop of NaCl injection in real time are presented. In addition, the amplitude-contrast image has less coherent noise by digital holography. PMID:23243569

  12. Detecting elementary excitations of a quantum simulator with superconducting resonator

    NASA Astrophysics Data System (ADS)

    Du, Lianghui; You, J. Q.; Tian, Lin

    2014-03-01

    Analog quantum simulators can emulate various many-body systems and can be used to study novel quantum correlations in such systems. One essential question in quantum simulation is how to detect the properties of the simulated many-body system, such as ground state property and spectrum of elementary excitations. Here we present a circuit QED approach for detecting the excitation spectrum of a quantum simulator by measuring the correlation spectrum of a superconducting resonator. For illustration, we apply this approach to a simulator for the transverse field Ising model coupling to a coplanar waveguide resonator. The simulator can be implemented with an array of superconducting flux qubits. We show that the resonance peaks in the correlation spectrum reveal exactly the frequencies of the excitations. The project was supported by NSF-0956064 and NSF-0916303.

  13. Sensitive magnetic force detection with a carbon nanotube resonator

    SciTech Connect

    Willick, Kyle; Haapamaki, Chris; Baugh, Jonathan

    2014-03-21

    We propose a technique for sensitive magnetic point force detection using a suspended carbon nanotube (CNT) mechanical resonator combined with a magnetic field gradient generated by a ferromagnetic gate electrode. Numerical calculations of the mechanical resonance frequency show that single Bohr magneton changes in the magnetic state of an individual magnetic molecule grafted to the CNT can translate to detectable frequency shifts, on the order of a few kHz. The dependences of the resonator response to device parameters such as length, tension, CNT diameter, and gate voltage are explored and optimal operating conditions are identified. A signal-to-noise analysis shows that, in principle, magnetic switching at the level of a single Bohr magneton can be read out in a single shot on timescales as short as 10 μs. This force sensor should enable new studies of spin dynamics in isolated single molecule magnets, free from the crystalline or ensemble settings typically studied.

  14. Magnetic resonance imaging findings in children with a first recognized seizure.

    PubMed

    Kalnin, Andrew J; Fastenau, Philip S; deGrauw, Ton J; Musick, Beverly S; Perkins, Susan M; Johnson, Cynthia S; Mathews, Vincent P; Egelhoff, John C; Dunn, David W; Austin, Joan K

    2008-12-01

    This study characterized structural abnormalities associated with onset of seizures in children, using magnetic resonance imaging and a standardized classification system in a large prospective cohort. Two hundred eighty-one children aged 6-14 years completed magnetic resonance imaging within 6 months of their first recognized seizure. Most examinations were performed with a standardized, dedicated seizure protocol; all were scored using a standard scoring system. At least one magnetic resonance imaging abnormality was identified in 87 of 281 (31%) children with a first recognized seizure. Two or more abnormalities were identified in 34 (12%). The commonest abnormalities were ventricular enlargement (51%), leukomalacia/gliosis (23%), gray-matter lesions such as heterotopias and cortical dysplasia (12%), volume loss (12%), other white-matter lesions (9%), and encephalomalacia (6%). Abnormalities defined as significant, or potentially related to seizures, occurred in 40 (14%). Temporal lobe and hippocampal abnormalities were detected at a higher frequency than in previous studies (13/87). Magnetic resonance imaging and a standardized, reliable, valid scoring system demonstrated a higher rate of abnormal findings than previously reported, including findings formerly considered incidental. Practice parameters may need revision, to expand the definition of significant abnormalities and support wider use of magnetic resonance imaging in children with newly diagnosed seizures. PMID:19027586

  15. Magnetic Resonance Detection of Individual Proton Spins Using Quantum Reporters

    NASA Astrophysics Data System (ADS)

    Sushkov, A. O.; Lovchinsky, I.; Chisholm, N.; Walsworth, R. L.; Park, H.; Lukin, M. D.

    2014-11-01

    We demonstrate a method of magnetic resonance imaging with single nuclear-spin sensitivity under ambient conditions. Our method employs isolated electronic-spin quantum bits (qubits) as magnetic resonance "reporters" on the surface of high purity diamond. These spin qubits are localized with nanometer-scale uncertainty, and their quantum state is coherently manipulated and measured optically via a proximal nitrogen-vacancy color center located a few nanometers below the diamond surface. This system is then used for sensing, coherent coupling, and imaging of individual proton spins on the diamond surface with angstrom resolution. Our approach may enable direct structural imaging of complex molecules that cannot be accessed from bulk studies. It realizes a new platform for probing novel materials, monitoring chemical reactions, and manipulation of complex systems on surfaces at a quantum level.

  16. Functional magnetic resonance imaging of awake monkeys: some approaches for improving imaging quality

    PubMed Central

    Chen, Gang; Wang, Feng; Dillenburger, Barbara C.; Friedman, Robert M.; Chen, Li M.; Gore, John C.; Avison, Malcolm J.; Roe, Anna W.

    2011-01-01

    Functional magnetic resonance imaging (fMRI), at high magnetic field strength can suffer from serious degradation of image quality because of motion and physiological noise, as well as spatial distortions and signal losses due to susceptibility effects. Overcoming such limitations is essential for sensitive detection and reliable interpretation of fMRI data. These issues are particularly problematic in studies of awake animals. As part of our initial efforts to study functional brain activations in awake, behaving monkeys using fMRI at 4.7T, we have developed acquisition and analysis procedures to improve image quality with encouraging results. We evaluated the influence of two main variables on image quality. First, we show how important the level of behavioral training is for obtaining good data stability and high temporal signal-to-noise ratios. In initial sessions, our typical scan session lasted 1.5 hours, partitioned into short (<10 minutes) runs. During reward periods and breaks between runs, the monkey exhibited movements resulting in considerable image misregistrations. After a few months of extensive behavioral training, we were able to increase the length of individual runs and the total length of each session. The monkey learned to wait until the end of a block for fluid reward, resulting in longer periods of continuous acquisition. Each additional 60 training sessions extended the duration of each session by 60 minutes, culminating, after about 140 training sessions, in sessions that last about four hours. As a result, the average translational movement decreased from over 500 μm to less than 80 μm, a displacement close to that observed in anesthetized monkeys scanned in a 7 T horizontal scanner. Another major source of distortion at high fields arises from susceptibility variations. To reduce such artifacts, we used segmented gradient-echo echo-planar imaging (EPI) sequences. Increasing the number of segments significantly decreased susceptibility

  17. Contraband Detection with Nuclear Resonance Fluorescence: Feasibility and Impact

    SciTech Connect

    Pruet, J; Lange, D

    2007-01-03

    In this report they show that cargo interrogation systems developed to thwart trafficking of illicit nuclear materials could also be powerful tools in the larger fight against contraband smuggling. In particular, in addition to detecting special nuclear materials, cargo scanning systems that exploit nuclear resonance fluorescence to detect specific isotopes can be used to help find: chemical weapons; some drugs as well as some chemicals regulated under the controlled substances act; precious metals; materials regulated under export control laws; and commonly trafficked fluorocarbons.

  18. Magnetic resonance image denoising using multiple filters

    NASA Astrophysics Data System (ADS)

    Ai, Danni; Wang, Jinjuan; Miwa, Yuichi

    2013-07-01

    We introduced and compared ten denoisingfilters which are all proposed during last fifteen years. Especially, the state-of-art denoisingalgorithms, NLM and BM3D, have attracted much attention. Several expansions are proposed to improve the noise reduction based on these two algorithms. On the other hand, optimal dictionaries, sparse representations and appropriate shapes of the transform's support are also considered for the image denoising. The comparison among variousfiltersis implemented by measuring the SNR of a phantom image and denoising effectiveness of a clinical image. The computational time is finally evaluated.

  19. Magnetic resonance imaging in central nervous system tuberculosis

    PubMed Central

    Trivedi, Richa; Saksena, Sona; Gupta, Rakesh K

    2009-01-01

    Tuberculosis (TB) in any form is a devastating disease, which in its most severe form involves the central nervous system (CNS), with a high mortality and morbidity. Early diagnosis of CNS TB is necessary for appropriate treatment to reduce this morbidity and mortality. Routine diagnostic techniques involve culture and immunological tests of the tissue and biofluids, which are time-consuming and may delay definitive management. Noninvasive imaging modalities such as computed tomography (CT) scan and magnetic resonance imaging (MRI) are routinely used in the diagnosis of neurotuberculosis, with MRI offering greater inherent sensitivity and specificity than CT scan. In addition to conventional MRI imaging, magnetization transfer imaging, diffusion imaging, and proton magnetic resonance spectroscopy techniques are also being evaluated for better tissue characterization in CNS TB. The current article reviews the role of various MRI techniques in the diagnosis and management of CNS TB. PMID:19881100

  20. 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 μm to yield picture elements of 50 × 50 × 1000 μm. 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.

  1. Correlating Hemodynamic Magnetic Resonance Imaging with high-field Intracranial Vessel Wall Imaging in Stroke

    PubMed Central

    Langdon, Weston; Donahue, Manus J.; van der Kolk, Anja G.; Rane, Swati; Strother, Megan K.

    2014-01-01

    Vessel wall magnetic resonance imaging at ultra-high field (7 Tesla) can be used to visualize vascular lesions noninvasively and holds potential for improving stroke-risk assessment in patients with ischemic cerebrovascular disease. We present the first multi-modal comparison of such high-field vessel wall imaging with more conventional (i) 3 Tesla hemodynamic magnetic resonance imaging and (ii) digital subtraction angiography in a 69-year-old male with a left temporal ischemic infarct. PMID:25426229

  2. 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

  3. Prion protein detection in serum using micromechanical resonator arrays.

    PubMed

    Varshney, Madhukar; Waggoner, Philip S; Montagna, Richard A; Craighead, Harold G

    2009-12-15

    Prion proteins that have transformed from their normal cellular counterparts (PrP(c)) into infectious form (PrP(res)) are responsible for causing progressive neurodegenerative diseases in numerous species, such as bovine spongiform encephalopathy (BSE) in cattle (also known as mad cow disease), scrapie in sheep, and Creutzfeldt-Jakob disease (CJD) in humans. Due to a possible link between BSE and CJD it is highly desirable to develop non-invasive and ante mortem tests for the detection of prion proteins in bovine samples. Such ante mortem tests of all cows prior to slaughter will help to prevent the introduction of PrP(res) into the human food supply. Furthermore, detection of PrP(res) in donated blood will also help to prevent the transmission of CJD among humans through blood transfusion. In this study, we have continued development of a micromechanical resonator array that is capable of detecting PrP(c) in bovine blood serum. The sensitivity of the resonators for the detection of PrP(c) is further enhanced by the use of secondary mass labels. A pair of antibodies is used in a sandwich immunoassay format to immobilize PrP(c) on the surface of resonators and attach nanoparticles as secondary mass labels to PrP(c). Secondary mass labeling is optimized in terms of incubation time to maximize the frequency shifts that correspond to the presence of PrP(c) on the surface of resonators. Our results show that a minimum of 200 pg mL(-1) of PrP(c) in blood serum can be detected using micromechanical resonator arrays. PMID:19836525

  4. Detection of Micro-Cracks on Metal Surfaces Using Near-Field Microwave Resonators

    NASA Astrophysics Data System (ADS)

    Kerouedan, J.; Quéffélec, P.; Talbot, P.; Quendo, C.; De Blasi, S.; Le Brun, A.

    2009-03-01

    This paper demonstrates how micro-cracks at the surface of metals can be detected and imaged by using near-field microwave resonators. It deals with two novel sensors: a first-order dual-behavior resonator (DBR) band-pass filter probe and a first-order DBR filter with an opening in the ground plane. Measurements results carried out on a stainless steel mock-up with several 200 μm wide EDM rectangular surface notches are presented showing the high sensitivity of the DBR probes and their ability to differentiate between notches of different depths.

  5. 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

  6. Magnetic Resonance Imaging: From Spin Physics to Medical Diagnosis

    NASA Astrophysics Data System (ADS)

    Nacher, Pierre-Jean

    Two rather similar historical evolutions are evoked, each one originating in fundamental spin studies by physicists, and ending as magnetic resonance imaging (MRI), a set of invaluable tools for clinical diagnosis in the hands of medical doctors. The first one starts with the early work on nuclear magnetic resonance, the founding stone of the usual proton-based MRI, of which the basic principles are described. The second one starts with the optical pumping developments made to study the effects of spin polarization in various fundamental problems. Its unexpected outcome is a unique imaging modality, also based on MRI, for the study of lung physiology and pathologies.

  7. Proliferation detection using a remote resonance Raman chemical sensor

    SciTech Connect

    Sedlacek, A.J.; Chen, C.L.; Dougherty, D.R.

    1993-08-01

    The authors discussed the potential of the resonance Raman chemical sensor as a remote sensor that can be used for gases, liquids or solids. This spectroscopy has the fundamental advantage that it is based on optical fingerprints that are insensitive to environmental perturbations or excitation frequency. By taking advantage of resonance enhancement, the inelastic scattering cross-section can increase anywhere from 4 to 6 orders of magnitude which translates into increased sensing range or lower detection limits. It was also shown that differential cross-sections as small as 10{sup {minus}27} cm{sup 2}/sr do not preclude the use of this technique as being an important component in one`s remote-sensing arsenal. The results obtained in the early 1970s on various pollutants and the more recent work on atmospheric water cast a favorable light on the prospects for the successful development of a resonance Raman remote sensor. Currently, of the 20 CW agent-related {open_quotes}signature{close_quotes} chemicals that the authors have investigated, 18 show enhancements ranging from 3 to 6 orders of magnitude. The absolute magnitudes of the measured resonance enhanced Raman cross-sections for these 18 chemicals suggest that detection and identification of trace quantities of the {open_quotes}signature{close_quotes} chemicals, through a remote resonance Raman chemical sensor, could be achieved.

  8. Magnetic Resonance Imaging Study on Blebs Morphology of Ahmed Valves

    PubMed Central

    Ferreira, Joana; Fernandes, Fernando; Patricio, Madalena; Brás, Ana; Rios, Cristina; Stalmans, Ingeborg

    2015-01-01

    ABSTRACT Purpose: To determine the morphometric parameters of filtration blebs of a valved aqueous humor drainage device. Materials and methods: Orbital magnetic resonances imaging (MRI) was taken after implantation of an Ahmed valve (FP7 model). Outcomes of the analysis were intraocular pressure (IOP) and the bleb’s morphometric analysis (volume, height, major and minor axis). Associations between IOP and the imaging-related study variables were explored by Spearman’s correlation test. Results: Eleven patients underwent orbital MRI examination. Recordings were taken after a mean of 2.7 months (1-6 months) after surgery. IOP was significantly lower than its preoperative values (17.6 ± 6.4 mm Hg vs 36.1 ± 6.4 mm Hg, p < 0.01). Mean bleb volume was 856.9 ± 261 mm3 and its height, major and minor axis were 5.77 ± 1.9, 14.8 ± 2.9 and 8.14 ± 3.6 mm, respectively. A positive correlation was detected between IOP and mean height (r = 0.77, p = 0.048) and major axis (r = 0.83, p = 0.03). Interestingly, the overall bleb volume was related to IOP levels immediately prior to surgery (r = 0.75, p < 0.01). Additionally, the posterior part of the plate was found to be displaced from the scleral surface in five cases (45%). Conclusion: Ahmed valve’s bleb morphology seems to correlate with both the pre- and postoperative IOP, which might suggest a clinical benefit of administering aqueous suppressants pre- as well as postoperatively. The plate of the device may show a significant dislocation from its initial surgical implantation site. How to cite this article: Ferreira J, Fernandes F, Patricio M, Brás A, Rios C, Stalmans I, Pinto LA. Magnetic Resonance Imaging Study on Blebs Morphology of Ahmed Valves. J Curr Glaucoma Pract 2015;9(1):1-5. PMID:26997824

  9. 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

  10. Magnetic resonance imaging of the pediatric brain

    SciTech Connect

    Salamon, G.; Raynaud, C.; Regis, J.; Rumeau, C.

    1990-01-01

    The atlas presents sequences of MRI sections parallel to the orbito-meatal plane in children from birth through the age of sixteen years. Each child was studied horizontally and sagitally and three-dimensional brain images were reconstructed to facilitate accurate identification of sulci and gyri. The images show crucial aspects of brain development such as the constancy of the brain stem and primitive brain from birth onward; the development of the telencephalon, characterized by deepening of sulci and growth of the cerebral cortex surface; and the different stages of white matter myelinization.

  11. Incidental extraspinal findings on magnetic resonance imaging of intervertebral discs

    PubMed Central

    Ayaz, Umit Yasar; Turanlı, Sevim; Saltas, Hakan; Karabacak, Osman Raif; Damar, Cagrı; Hekimoglu, Baki

    2014-01-01

    Introduction We aimed to evaluate pathological extraspinal findings and congenital anomalies/anatomical variations that were incidentally detected on the magnetic resonance imaging (MRI) scans of intervertebral discs, to find the frequencies of these incidental findings, and to emphasise the clinical importance of them. Material and methods A retrospective study including 1031 consecutive patients (730 females and 301 males, with a median age of 46 years) was conducted by evaluating a total of 1106 MRI examinations of intervertebral discs. Examinations were performed with a 1.5 T MRI unit. Incidental findings were classified as pathological findings and congenital anomalies/anatomical variations. Results The percentages of incidental extraspinal pathological findings and congenital anomalies/anatomical variations were 16.6% (95% confidence interval (CI): 14.4–18.8) and 3.7% (95% CI: 2.6–4.3), respectively. The percentage of incidental extraspinal pathological findings on cervical spinal MRI was 25.7% (95% CI: 20.1–31.7), thyroid nodules being the most common incidental findings. On thoracic spinal MRI (n = 19), inferior pole thyroid nodules were demonstrated as incidental extraspinal pathological findings, with a percentage of 10.5% (95% CI: 9.6–11.5). On lumbar spinal MRI, incidental pathological findings were detected with a percentage of 14.2% (95% CI: 11.9–16.6), while the percentage of congenital anomalies/anatomical variations was 4.8% (95% CI: 3.4–6.3). Eventually, 6.5% (95% CI: 2.6–9.4) of all cases with incidental extraspinal pathological findings underwent surgery. Conclusions On MRI examination of intervertebral discs, paying attention to incidentally detected pathological extraspinal findings and congenital anomalies/anatomical variations is very important due to the fact that they can alter the treatment of the patient or affect the patient's life. PMID:25276162

  12. On-chip magnetoresistive detection of resonance in microcantilevers

    NASA Astrophysics Data System (ADS)

    Patil, S. B.; Guedes, A.; Freitas, P. P.; Cardoso, S.; Chu, V.; Conde, J. P.

    2009-07-01

    Magnetoresistive spin-valve sensors were used to provide on-chip detection of the mechanical resonance of a thin silicon microelectromechanical systems cantilever. The spin-valve sensor was placed underneath the free end of the cantilever. A CoCrPt thin-film permanent magnet was placed on top of the amorphous silicon/Al cantilever. The cantilever was electrostatically actuated and its deflection creates a change in the magnetic field that can be sensed by the spin-valve sensor. The resonance frequency of the structure in the megahertz range is detected by the measurement of the spin-valve sensor output. Minimum deflection detection limit is determined to be 0.06 Å/Hz1/2.

  13. Quantitative simultaneous positron emission tomography and magnetic resonance imaging

    PubMed Central

    Ouyang, Jinsong; Petibon, Yoann; Huang, Chuan; Reese, Timothy G.; Kolnick, Aleksandra L.; El Fakhri, Georges

    2014-01-01

    Abstract. Simultaneous positron emission tomography and magnetic resonance imaging (PET-MR) is an innovative and promising imaging modality that is generating substantial interest in the medical imaging community, while offering many challenges and opportunities. In this study, we investigated whether MR surface coils need to be accounted for in PET attenuation correction. Furthermore, we integrated motion correction, attenuation correction, and point spread function modeling into a single PET reconstruction framework. We applied our reconstruction framework to in vivo animal and patient PET-MR studies. We have demonstrated that our approach greatly improved PET image quality. PMID:26158055

  14. Quantitative simultaneous positron emission tomography and magnetic resonance imaging.

    PubMed

    Ouyang, Jinsong; Petibon, Yoann; Huang, Chuan; Reese, Timothy G; Kolnick, Aleksandra L; El Fakhri, Georges

    2014-10-01

    Simultaneous positron emission tomography and magnetic resonance imaging (PET-MR) is an innovative and promising imaging modality that is generating substantial interest in the medical imaging community, while offering many challenges and opportunities. In this study, we investigated whether MR surface coils need to be accounted for in PET attenuation correction. Furthermore, we integrated motion correction, attenuation correction, and point spread function modeling into a single PET reconstruction framework. We applied our reconstruction framework to in vivo animal and patient PET-MR studies. We have demonstrated that our approach greatly improved PET image quality. PMID:26158055

  15. Silicone-induced Penile Sclerosing Lipogranuloma: Magnetic Resonance Imaging Findings.

    PubMed

    Tsili, Athina C; Xiropotamou, Olga N; Nomikos, Michael; Argyropoulou, Maria I

    2016-01-01

    Sclerosing lipogranuloma is a rare benign disease, representing a peculiar granulomatous reaction of fatty tissue. The majority of cases are secondary to injection of exogenous foreign bodies, such as silicone, paraffin, mineral, or vegetable oils. To the best of our knowledge, we present the first case of a silicone-induced penile lipogranuloma in a 52-year-old man evaluated with a multiparametric magnetic resonance imaging (MRI) protocol, including diffusion-weighted imaging, magnetization transfer imaging, and dynamic contrast-enhanced MRI. MRI of the penis by combining both conventional and functional information represents an important imaging tool in the preoperative workup of silicone-induced penile lipogranuloma. PMID:26958433

  16. Silicone-induced Penile Sclerosing Lipogranuloma: Magnetic Resonance Imaging Findings

    PubMed Central

    Tsili, Athina C; Xiropotamou, Olga N; Nomikos, Michael; Argyropoulou, Maria I

    2016-01-01

    Sclerosing lipogranuloma is a rare benign disease, representing a peculiar granulomatous reaction of fatty tissue. The majority of cases are secondary to injection of exogenous foreign bodies, such as silicone, paraffin, mineral, or vegetable oils. To the best of our knowledge, we present the first case of a silicone-induced penile lipogranuloma in a 52-year-old man evaluated with a multiparametric magnetic resonance imaging (MRI) protocol, including diffusion-weighted imaging, magnetization transfer imaging, and dynamic contrast-enhanced MRI. MRI of the penis by combining both conventional and functional information represents an important imaging tool in the preoperative workup of silicone-induced penile lipogranuloma. PMID:26958433

  17. Single Molecule Magnetic Force Detection with a Carbon Nanotube Resonator

    NASA Astrophysics Data System (ADS)

    Willick, Kyle; Walker, Sean; Baugh, Jonathan

    2015-03-01

    Single molecule magnets (SMMs) sit at the boundary between macroscopic magnetic behaviour and quantum phenomena. Detecting the magnetic moment of an individual SMM would allow exploration of this boundary, and could enable technological applications based on SMMs such as quantum information processing. Detection of these magnetic moments remains an experimental challenge, particularly at the time scales of relaxation and decoherence. We present a technique for sensitive magnetic force detection that should permit such measurements. A suspended carbon nanotube (CNT) mechanical resonator is combined with a magnetic field gradient generated by a ferromagnetic gate electrode, which couples the magnetic moment of a nanomagnet to the resonant motion of the CNT. Numerical calculations of the mechanical resonance show that resonant frequency shifts on the order of a few kHz arise due to single Bohr magneton changes in magnetic moment. A signal-to-noise analysis based on thermomechanical noise shows that magnetic switching at the level of a Bohr magneton can be measured in a single shot on timescales as short as 10 μs. This sensitivity should enable studies of the spin dynamics of an isolated SMM, within the spin relaxation timescales for many available SMMs. Supported by NSERC.

  18. Thermoelectric detection of ferromagnetic resonance of a nanoscale ferromagnet.

    PubMed

    Bakker, F L; Flipse, J; Slachter, A; Wagenaar, D; van Wees, B J

    2012-04-20

    We present thermoelectric measurements of the heat dissipated due to ferromagnetic resonance of a Permalloy strip. A microwave magnetic field, produced by an on-chip coplanar strip waveguide, is used to drive the magnetization precession. The generated heat is detected via Seebeck measurements on a thermocouple connected to the ferromagnet. The observed resonance peak shape is in agreement with the Landau-Lifshitz-Gilbert equation and is compared with thermoelectric finite-element modeling. Unlike other methods, this technique is not restricted to electrically conductive media and is therefore also applicable to for instance ferromagnetic insulators. PMID:22680756

  19. Element Selective X-ray Detected Magnetic Resonance

    SciTech Connect

    Goulon, J.; Rogalev, A.; Wilhelm, F.; Jaouen, N.; Goulon-Ginet, C.; Goujon, G.; Youssef, J. Ben; Indenbom, M. V.

    2007-01-19

    Element selective X-ray Detected Magnetic Resonance (XDMR) was measured on exciting the Fe K-edge in a high quality YIG thin film. Resonant pumping at high microwave power was achieved in the nonlinear foldover regime and X-ray Magnetic Circular Dichroism (XMCD) was used to probe the time-invariant change of the magnetization {delta}Mz due to the precession of orbital magnetization densities of states (DOS) at the Fe sites. This challenging experiment required us to design a specific instrumentation which is briefly described.

  20. [Current value of magnetic resonance imaging for diagnosis of coronary heart disease].

    PubMed

    Wiesmann, F; Taylor, A M; Neubauer, S; Pennell, D J

    1997-09-01

    Magnetic Resonance Imaging (MRI) is a non-invasive imaging technique with increasing importance in clinical medicine. It has become a valuable and reliable imaging tool in the diagnosis and management of many medical and surgical conditions. Important advantages of MRI are its flexibility in orientation of imaging plane and the possibility of both anatomical and functional imaging. MRI is based on the application and detection of radio signals and works without any exposure to ionizing radiation, and therefore it is regarded as a safe imaging technique. In the heart there are well established imaging indications such as in acquired and congenital heart disease, pericardial and aortic disease and visualisation of cardiac masses and hypertrophy. Its applications in coronary artery disease (CAD) have been relatively limited, but recent developments in ultrafast imaging sequences and computer hardware have led to a considerable improvement in spatial and temporal image resolution. This has made applications in CAD a possibility, particularly coronary imaging and myocardial perfusion imaging. Recent clinical studies report good correlation between Magnetic Resonance Coronary Angiography (MRCA) and conventional x-ray contrast angiography in the detection of coronary lesions. In the assessment of coronary artery bypass graft (CABG) patency and the definition of anomalous coronary arteries, MRI showed good sensitivity and specificity. The first results of coronary artery flow measurements have now been reported. Myocardial perfusion imaging and stress-ventriculography for detection of wall motion abnormalities are reported as indirect imaging methods with high reliability and clinical value in the diagnosis of CAD. This overview describes recent developments in cardiac MRI and assesses the current and future value of MRI for clinical cardiology. PMID:9441526

  1. Resonance detection of dark matter axions using a DC SQUID

    NASA Astrophysics Data System (ADS)

    Popov, V. A.

    2016-02-01

    A method for detecting dark matter axions in which a dc SQUID serves as a detector is proposed. The SQUID is shown to be able to detect the magnetic field perturbations induced by its interaction with axions. The resonance signal appears as a current step in the SQUID current-voltage characteristic. The voltage of the step corresponds to the axion mass, while its height depends on the axion energy density in near-Earth space. The proposed method is aimed at detecting axions with masses m a ≲ 10-4 eV, which are of interest for both cosmology and particle physics.

  2. Broadband, large-area microwave antenna for optically detected magnetic resonance of nitrogen-vacancy centers in diamond.

    PubMed

    Sasaki, Kento; Monnai, Yasuaki; Saijo, Soya; Fujita, Ryushiro; Watanabe, Hideyuki; Ishi-Hayase, Junko; Itoh, Kohei M; Abe, Eisuke

    2016-05-01

    We report on a microwave planar ring antenna specifically designed for optically detected magnetic resonance (ODMR) of nitrogen-vacancy (NV) centers in diamond. It has the resonance frequency at around 2.87 GHz with the bandwidth of 400 MHz, ensuring that ODMR can be observed under external magnetic fields up to 100 G without the need of adjustment of the resonance frequency. It is also spatially uniform within the 1-mm-diameter center hole, enabling the magnetic-field imaging in the wide spatial range. These features facilitate the experiments on quantum sensing and imaging using NV centers at room temperature. PMID:27250439

  3. Geostationary microwave imagers detection criteria

    NASA Technical Reports Server (NTRS)

    Stacey, J. M.

    1986-01-01

    Geostationary orbit is investigated as a vantage point from which to sense remotely the surface features of the planet and its atmosphere, with microwave sensors. The geometrical relationships associated with geostationary altitude are developed to produce an efficient search pattern for the detection of emitting media and metal objects. Power transfer equations are derived from the roots of first principles and explain the expected values of the signal-to-clutter ratios for the detection of aircraft, ships, and buoys and for the detection of natural features where they are manifested as cold and warm eddies. The transport of microwave power is described for modeled detection where the direction of power flow is explained by the Zeroth and Second Laws of Thermodynamics. Mathematical expressions are derived that elucidate the detectability of natural emitting media and metal objects. Signal-to-clutter ratio comparisons are drawn among detectable objects that show relative detectability with a thermodynamic sensor and with a short-pulse radar.

  4. Landmine detection using passive hyperspectral imaging

    NASA Astrophysics Data System (ADS)

    McFee, John E.; Anger, Cliff; Achal, Steve; Ivanco, Tyler

    2007-04-01

    Airborne hyperspectral imaging has been studied since the late 1980s as a tool to detect minefields for military countermine operations and for level I clearance for humanitarian demining. Hyperspectral imaging employed on unmanned ground vehicles may also be used to augment or replace broadband imagers to detect individual mines. This paper will discuss the ability of different optical wavebands - the visible/near infrared (VNIR), shortwave infrared (SWIR) and thermal infrared (TIR) - to detect surface-laid and buried mines. The phenomenology that determines performance in the different bands is discussed. Hyperspectral imagers have usually been designed and built for general purpose remote sensing applications and often do not meet the requirements of mine detection. The DRDC mine detection research program has sponsored the development by Itres Research of VNIR, SWIR and TIR instruments specifically intended for mine detection. The requirements for such imagers are described, as well as the instruments. Some results of mine detection experiments are presented. To date, reliable day time detection of surface-laid mines in non-real-time, independent of solar angle, time of day and season has been demonstrated in the VNIR and SWIR. Real-time analysis, necessary for military applications, has been demonstrated from low speed ground vehicles and recently from airborne platforms. Reliable, repeatable detection of buried mines has yet to be demonstrated, although a recently completed TIR hyperspectral imager will soon be tested for such a capability.

  5. Clinical applications of magnetic resonance imaging - current status

    SciTech Connect

    Cammoun, D.; Hendee, W.R.; Davis, K.A.

    1985-12-01

    Magnetic resonance imaging has far-reaching real and possible clinical applications. Its usefulness has been best explored and realized in the central nervous system, especially the posterior fossa and brain stem, where most abnormalities are better identified than with computed tomography. Its lack of ionizing radiation and extreme sensitivity to normal and abnormal patterns of myelination make magnetic resonance imaging advantageous for diagnosing many neonatal and pediatric abnormalities. New, reliable cardiac gating techniques open the way for promising studies of cardiac anatomy and function. The ability to image directly in three orthogonal planes gives us new insight into staging and follow-up of pelvic tumors and other pelvic abnormalities. Exquisite soft tissue contrast, far above that attainable by other imaging modalities, has made possible the early diagnosis of traumatic ligamentous knee injury, avascular necrosis of the hip and diagnosis, treatment planning and follow-up of musculoskeletal neoplasms. 59 references, 9 figures.

  6. Basic principles of magnetic resonance imaging--an update.

    PubMed

    Scherzinger, A L; Hendee, W R

    1985-12-01

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

  7. Brain magnetic resonance imaging with contrast dependent on blood oxygenation

    SciTech Connect

    Ogawa, S.; Lee, T.M.; Kay, A.R.; Tank, D.W. )

    1990-12-01

    Paramagnetic deoxyhemoglobin in venous blood is a naturally occurring contrast agent for magnetic resonance imaging (MRI). By accentuating the effects of this agent through the use of gradient-echo techniques in high yields, the authors demonstrate in vivo images of brain microvasculature with image contrast reflecting the blood oxygen level. This blood oxygenation level-dependent (BOLD) contrast follows blood oxygen changes induced by anesthetics, by insulin-induced hypoglycemia, and by inhaled gas mixtures that alter metabolic demand or blood flow. The results suggest that BOLD contrast can be used to provide in vivo real-time maps of blood oxygenation in the brain under normal physiological conditions. BOLD contrast adds an additional feature to magnetic resonance imaging and complement other techniques that are attempting to provide position emission tomography-like measurements related to regional neural activity.

  8. Brain Magnetic Resonance Imaging with Contrast Dependent on Blood Oxygenation

    NASA Astrophysics Data System (ADS)

    Ogawa, S.; Lee, T. M.; Kay, A. R.; Tank, D. W.

    1990-12-01

    Paramagnetic deoxyhemoglobin in venous blood is a naturally occurring contrast agent for magnetic resonance imaging (MRI). By accentuating the effects of this agent through the use of gradient-echo techniques in high fields, we demonstrate in vivo images of brain microvasculature with image contrast reflecting the blood oxygen level. This blood oxygenation level-dependent (BOLD) contrast follows blood oxygen changes induced by anesthetics, by insulin-induced hypoglycemia, and by inhaled gas mixtures that alter metabolic demand or blood flow. The results suggest that BOLD contrast can be used to provide in vivo real-time maps of blood oxygenation in the brain under normal physiological conditions. BOLD contrast adds an additional feature to magnetic resonance imaging and complements other techniques that are attempting to provide positron emission tomography-like measurements related to regional neural activity.

  9. An electrochemical surface plasmon resonance imaging system targeting cell analysis

    NASA Astrophysics Data System (ADS)

    Zhang, L. L.; Chen, X.; Wei, H. T.; Li, H.; Sun, J. H.; Cai, H. Y.; Chen, J. L.; Cui, D. F.

    2013-08-01

    This paper presents an electrochemical-surface plasmon resonance imaging (EC-SPRI) system, enabling the characterization of optical and electrical properties of cells, simultaneously. The developed surface plasmon resonance (SPR) imaging system was capable of imaging micro cavities with a dimension of 10 μm × 10 μm and differentiated glycerol solutions with a group of refractive indices (RIs). Furthermore, the EC-SPRI system was used to image A549 cells, suggesting corresponding RI and morphology changes during the cell death process. In the end, electrochemical and SPR methods were used in combination, recording oxidation peaks of A549 cells in the cyclic voltage curves and SPR response unit increase, simultaneously.

  10. Clinical applications of high-resolution ocular magnetic resonance imaging.

    PubMed

    Tanitame, Keizo; Sone, Takashi; Kiuchi, Yoshiaki; Awai, Kazuo

    2012-11-01

    Magnetic resonance imaging (MRI) using fast sequences with subjects staring at a target can provide motion-free ocular images, and small receiver surface coils make it possible to produce ocular images with high spatial resolution. MRI using half-Fourier single-shot rapid acquisition with a relaxation enhancement sequence as a fast T2-weighted imaging yields useful images for the morphologic diagnosis of ocular diseases, and MRI using a fast spoiled gradient-recalled-echo sequence as a T1-weighted imaging yields additional information by the administration of gadolinium-based contrast material for assessing the vascularity of intraocular tumors. These ocular imaging techniques are useful for the evaluation of patients with angle closure glaucoma, congenital abnormality of ocular globes, intraocular tumors and several types of detachments, as well as patients after ocular surgery. In this pictorial essay, we demonstrate the clinical applications of fast high-resolution ocular MRI with fixation of the subjects' visual foci. PMID:22923185

  11. 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

  12. 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.

  13. X-ray image detection apparatus

    SciTech Connect

    Trepte, W.

    1980-11-11

    X-ray image detection apparatus in which an image detector is pivotally mounted on a carrier arm which in turn is pivotally mounted on a vertical column. A sprocket wheel and chain arrangement operatively interconnects the image detector, the carrier arm and the vertical column such that as the carrier arm is pivoted about a horizontal axis in one direction relative to the vertical column, the image detector is pivoted in an opposite direction.

  14. [Cardiac magnetic resonance imaging in evaluation of coronary artery disease].

    PubMed

    Bayraktaroğlu, Selen; Alper, Hüdaver

    2008-07-01

    Considerable advances have been achieved in cardiovascular magnetic resonance imaging (MRI) technology, and MRI has become an important noninvasive imaging tool in the management of coronary artery disease. Cardiac MRI can provide information about myocardial perfusion, viability and contractile reserve. The information obtained not only provides diagnostic information but also has an important prognostic value. This article reviews the recent advances in cardiac MRI for evaluation of coronary artery disease. PMID:18611838

  15. Magnetic resonance perfusion imaging in proliferative cerebral angiopathy.

    PubMed

    Vargas, María Catalina; Castillo, Mauricio

    2011-01-01

    Cerebral proliferative angiopathy (CPA) is an unusual type of vascular malformation with unique clinical and imaging characteristics that distinguish it from the classic arteriovenous malformations. The features of CPA include absence of dominant arterial feeders or flow-related aneurysms, capillary angioectasia without large draining veins, and presence of intermingled normal brain parenchyma that is hypoperfused. We describe the magnetic resonance imaging findings including perfusion in 3 patients with CPA. PMID:21245687

  16. 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.

  17. Intraocular lymphoma after cardiac transplantation: magnetic resonance imaging findings.

    PubMed

    Kim, Yi Kyung; Kim, Hyung-Jin; Woo, Kyung In; Kim, Yoon-Duck

    2013-01-01

    We report a case of intraocular lymphoma in a 65-year-old man, 15 months after cardiac transplantation. On Magnetic Resonance (MR) images, the iris and the anterior chamber of the right eye were found to be involved with an enhancing soft-tissue lesion. To our knowledge, this is the first case of post-transplantation intraocular lymphoma evaluated with MR imaging. PMID:23323042

  18. Cyst infection in unilateral renal cystic disease and the role of diffusion-weighted magnetic resonance imaging.

    PubMed

    Takase, Yasukazu; Kodama, Koichi; Motoi, Isamu; Saito, Katsuhiko

    2012-11-01

    In multicystic renal diseases, cyst infection is a complex issue because of the absence of validated diagnostic methods. Unilateral renal cystic disease is a rare multicystic disease, believed to have an acquired maldevelopmental origin. Unilateral renal cystic disease is often confused with autosomal dominant polycystic kidney disease but has some distinguishing characteristics: unilateral localization, negative family history, and no progression to chronic renal failure. We describe a case of unilateral renal cystic disease with cyst infection that could be detected by diffusion-weighted magnetic resonance imaging, but not by conventional imaging techniques. Diffusion-weighted magnetic resonance imaging can be useful for detecting infected cysts, especially in multicystic renal diseases. PMID:22990058

  19. Efficient bias correction for magnetic resonance image denoising.

    PubMed

    Mukherjee, Partha Sarathi; Qiu, Peihua

    2013-05-30

    Magnetic resonance imaging (MRI) is a popular radiology technique that is used for visualizing detailed internal structure of the body. Observed MRI images are generated by the inverse Fourier transformation from received frequency signals of a magnetic resonance scanner system. Previous research has demonstrated that random noise involved in the observed MRI images can be described adequately by the so-called Rician noise model. Under that model, the observed image intensity at a given pixel is a nonlinear function of the true image intensity and of two independent zero-mean random variables with the same normal distribution. Because of such a complicated noise structure in the observed MRI images, denoised images by conventional denoising methods are usually biased, and the bias could reduce image contrast and negatively affect subsequent image analysis. Therefore, it is important to address the bias issue properly. To this end, several bias-correction procedures have been proposed in the literature. In this paper, we study the Rician noise model and the corresponding bias-correction problem systematically and propose a new and more effective bias-correction formula based on the regression analysis and Monte Carlo simulation. Numerical studies show that our proposed method works well in various applications. PMID:23074149

  20. Direct neural current imaging in an intact cerebellum with magnetic resonance imaging.

    PubMed

    Sundaram, Padmavathi; Nummenmaa, Aapo; Wells, William; Orbach, Darren; Orringer, Daniel; Mulkern, Robert; Okada, Yoshio

    2016-05-15

    The ability to detect neuronal currents with high spatiotemporal resolution using magnetic resonance imaging (MRI) is important for studying human brain function in both health and disease. While significant progress has been made, we still lack evidence showing that it is possible to measure an MR signal time-locked to neuronal currents with a temporal waveform matching concurrently recorded local field potentials (LFPs). Also lacking is evidence that such MR data can be used to image current distribution in active tissue. Since these two results are lacking even in vitro, we obtained these data in an intact isolated whole cerebellum of turtle during slow neuronal activity mediated by metabotropic glutamate receptors using a gradient-echo EPI sequence (TR=100ms) at 4.7T. Our results show that it is possible (1) to reliably detect an MR phase shift time course matching that of the concurrently measured LFP evoked by stimulation of a cerebellar peduncle, (2) to detect the signal in single voxels of 0.1mm(3), (3) to determine the spatial phase map matching the magnetic field distribution predicted by the LFP map, (4) to estimate the distribution of neuronal current in the active tissue from a group-average phase map, and (5) to provide a quantitatively accurate theoretical account of the measured phase shifts. The peak values of the detected MR phase shifts were 0.27-0.37°, corresponding to local magnetic field changes of 0.67-0.93nT (for TE=26ms). Our work provides an empirical basis for future extensions to in vivo imaging of neuronal currents. PMID:26899788