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Sample records for remote detection mri

  1. Remote NMR/MRI detection of laser polarized gases

    Science.gov (United States)

    Pines, Alexander; Saxena, Sunil; Moule, Adam; Spence, Megan; Seeley, Juliette A.; Pierce, Kimberly L.; Han, Song-I; Granwehr, Josef

    2006-06-13

    An apparatus and method for remote NMR/MRI spectroscopy having an encoding coil with a sample chamber, a supply of signal carriers, preferably hyperpolarized xenon and a detector allowing the spatial and temporal separation of signal preparation and signal detection steps. This separation allows the physical conditions and methods of the encoding and detection steps to be optimized independently. The encoding of the carrier molecules may take place in a high or a low magnetic field and conventional NMR pulse sequences can be split between encoding and detection steps. In one embodiment, the detector is a high magnetic field NMR apparatus. In another embodiment, the detector is a superconducting quantum interference device. A further embodiment uses optical detection of Rb--Xe spin exchange. Another embodiment uses an optical magnetometer using non-linear Faraday rotation. Concentration of the signal carriers in the detector can greatly improve the signal to noise ratio.

  2. Sensitivity Quantification of Remote Detection NMR and MRI

    Energy Technology Data Exchange (ETDEWEB)

    Granwehr, Josef; Seeley, Juliette A.

    2005-10-25

    A sensitivity analysis of the remote detection NMR techniqueis presented. With remote detection, information about a sample isencoded onto a mobile sensor fluid, which facilitates a spatialseparation of encoding and detection of spin magnetization. This approachcan be interpreted as a two-dimensional NMR experiment, therefore thesame general formalism can be used for a sensitivity analysis. Eventhough remote detection is a point-by-point experiment, the sensitivitydoes not scale unfavorably with the number of detected points compared totransient detection. It is proportional to the relative sensitivitybetween the remote detector and the circuit that is used for encoding.The influence of the different signal decay times is analyzed, and thedistinction between spectroscopy and imaging experiments ismade.

  3. Gradient-free microfluidic flow labeling using thin magnetic films and remotely detected MRI

    Science.gov (United States)

    Halpern-Manners, Nicholas W.; Kennedy, Daniel J.; Trease, David R.; Teisseyre, Thomas Z.; Malecek, Nicolas S.; Pines, Alexander; Bajaj, Vikram S.

    2014-12-01

    Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI) may be employed as noninvasive measurements yielding detailed information about the chemical and physical parameters that define microscale flows. Despite these advantages, magnetic resonance has been difficult to combine with microfluidics, largely due to its low sensitivity when detecting small sample volumes and the difficulty of efficiently addressing individual flow pathways for parallel measurements without utilizing large electric currents to create pulsed magnetic field gradients. Here, we demonstrate that remotely-detected MRI (RD-MRI) employing static magnetic field gradients produced by thin magnetic films can be used to encode flow and overcome some of these limitations. We show how flow path and history can be selected through the use of these thin film labels and through the application of synchronized, frequency-selective pulses. This obviates the need for large electric currents to produce pulsed magnetic field gradients and may allow for further application of NMR and MRI experiments on microscale devices.

  4. Quantifying the Diffusion of a Fluid through Membranes by RemoteDetection MRI

    Energy Technology Data Exchange (ETDEWEB)

    Telkki, Ville-Veikko; Hilty, Christian; Garcia, Sandra; Harel,Elad; Pines, Alexander

    2006-10-24

    We present a method to measure self-diffusion acrossmembranes without the need for concentration or pressure gradients.Hyperpolarized xenon in combination with remote detection of NMR allowsthe measurement of membrane permeation, even in the gas phase. Theresulting images allow quantification of the amount of fluid diffusedthrough the membrane, and represent an alternative, potentially moreprecise way of measuring a membrane diffusion coefficient. The use ofremote detection of NMR allows for non-invasive signal encoding coupledto sensitive detection, making this approach ideal for the study ofdiffusion in intact devices such as fuel cells or separationsystems.

  5. Remote detection system

    International Nuclear Information System (INIS)

    A newly designed remote detection system has been developed at Los Alamos that allows the collection of high-resolution gamma-ray spectra and neutron data from a remote location. The system consists of the remote unit and a command unit. The remote unit collects data in a potentially hostile environment while the operator controls the unit by either radio or wire link from a safe position. Both units are battery powered and are housed in metal carrying cases

  6. Functional MRI in Prostate Cancer Detection

    OpenAIRE

    Sandeep Sankineni; Murat Osman; Choyke, Peter L

    2014-01-01

    Multiparametric magnetic resonance imaging (MP-MRI) has emerged as a promising method for the detection of prostate cancer. The functional MRI components of the MP-MRI consist of the diffusion weighted MRI, dynamic contrast enhanced MRI, and magnetic resonance spectroscopic imaging. The purpose of this paper is to review the existing literature about the use of functional MRI in prostate cancer detection.

  7. Remote control catheter navigation: options for guidance under MRI

    OpenAIRE

    Muller Leah; Saeed Maythem; Wilson Mark W; Hetts Steven W

    2012-01-01

    Abstract Background Image-guided endovascular interventions have gained increasing popularity in clinical practice, and magnetic resonance imaging (MRI) is emerging as an attractive alternative to X-ray fluoroscopy for guiding such interventions. Steering catheters by remote control under MRI guidance offers unique challenges and opportunities. Methods In this review, the benefits and limitations of MRI-guided remote control intervention are addressed, and the tools for guiding such intervent...

  8. Remote detection of OH

    Science.gov (United States)

    Mcdermid, I. Stuart; Laudenslager, James B.

    1986-01-01

    This is a remote measurement technique utilizing a XeCl excimer laser tuned to the Q sub 21 1 rotational transition of the 0-0, A-X band at 307.847 nm. A wavemeter is under development to monitor, on a pulse-to-pulse basis, both the laser lineshape and absolute wavelength. Fluorescence is detected with a multiple Fabry-Perot type filter with a spectral resolution on the order of 0.001 nm. This is tuned to the overlapping Q sub 2 2, Q sub 12 2, Q sub 2 3, and Q sub 12 3 rotational transitions at 308.986 nm. The fringe pattern from this filter is imaged using a discrete, multi-anode detector which has a photon gain of 10 to the 8th power. This permits the simultaneous monitoring of OH fluorescence, N2 and/or O2 rotational Raman scattering and broadband background levels. The use of three etalons in series provides sufficient rejection, approx. greater than 10 to the 10th power, against the laser radiation only 1.2 nm away.

  9. Remote control catheter navigation: options for guidance under MRI

    Directory of Open Access Journals (Sweden)

    Muller Leah

    2012-06-01

    Full Text Available Abstract Background Image-guided endovascular interventions have gained increasing popularity in clinical practice, and magnetic resonance imaging (MRI is emerging as an attractive alternative to X-ray fluoroscopy for guiding such interventions. Steering catheters by remote control under MRI guidance offers unique challenges and opportunities. Methods In this review, the benefits and limitations of MRI-guided remote control intervention are addressed, and the tools for guiding such interventions in the magnetic environment are summarized. Designs for remote control catheter guidance include a catheter tip electromagnetic microcoil design, a ferromagnetic sphere-tipped catheter design, smart material-actuated catheters, and hydraulically actuated catheters. Remote control catheter guidance systems were compared and contrasted with respect to visualization, safety, and performance. Performance is characterized by bending angles achievable by the catheter, time to achieve bending, degree of rotation achievable, and miniaturization capacity of the design. Necessary improvements for furthering catheter design, especially for use in the MRI environment, are addressed, as are hurdles that must be overcome in order to make MRI guided endovascular procedures more accessible for regular use in clinical practice. Conclusions MR-guided endovascular interventions under remote control steering are in their infancy due to issues regarding safety and reliability. Additional experimental studies are needed prior to their use in humans.

  10. Alzheimer Disease detection on structural MRI

    OpenAIRE

    Ben Ahmed, Olfa; Benois-Pineau, Jenny; Allard, Michèle; Ben Amar, Chokri; Catheline, Gwenaelle

    2013-01-01

    Alzheimer disease (AD) is the most common form of dementia. Structural (MRI) measurements allow detecting and following the evolution of brain atrophy which is a marker of the disease process. Recently, several pattern recognition methods have been proposed to automatically discriminate between patients with and without Alzheimer disease . Support Vector Machines help to identify patterns in data that differentiate between several classes. Hippocampus is the principal region involved in AD. I...

  11. Remote detection device and detection method therefor

    International Nuclear Information System (INIS)

    The present invention provides a non-destructive detection device for collectively, efficiently and effectively conducting maintenance and detection for confirming the integrity of a nuclear reactor by way of a shielding member for shielding radiation rays generated from an objective portion to be detected. Namely, devices for direct visual detection using an under water TV camera as a sensor, an eddy current detection using a coil as a sensor and each magnetic powder flow detection are integrated and applied collectively. Specifically, the visual detection by using the TV camera and the eddy current flaw detection are adopted together. The flaw detection with magnetic powder is applied as a means for confirming the results of the two kinds of detections by other method. With such procedures, detection techniques using respective specific theories are combined thereby enabling to enhance the accuracy for the evaluation of the detection. (I.S.)

  12. Vehicle Detection from Remote Sensing Images

    International Nuclear Information System (INIS)

    Image object detection is an important application of remote sensing technology. Road vehicle detection using very high-resolution remote sensing images has a unique advantage of covering a large area such as Jaddah and Alriad at the same time over all ground-based detectors. But the detection of small vehicle-object in remote sensing imagery is still a challenging task. Several parameters of gray values and sizes are examined to classify the objects in the image. The vehicles and their associated shadows can be discriminated by removing big objects such as roads. Our test shows a promising result of detecting the vehicle. We present an object-based detection approach with Imagine Objective for the detected vehicles in the study area, (Jeddah city, Alriad city ) Imagine Objective employs feature models working on objects produced by image segmentation and various other pixel-based algorithms can be processed by geometric and textural parameters after being vectorized. This process is used and optimised for the extraction of the vehicles from high resolution images. Preliminary object detection tests using a semi automated post-classification approach show reliable results. For this research, the applied methods prove to be useful to detect vehicles on the road of example images even without producing a complete extraction of all vehicles. The approach will be extended to the whole images area

  13. A radiation remote detection device

    International Nuclear Information System (INIS)

    The radiation detection device is composed of an optical fiber, a sensing crystal, which, when interacting with a radiation, emits light that propagates through the fiber optic, and an optic sheath surrounding the crystal. The sheath refractive index is inferior to the crystal index, thus ensuring that the light is totally confined. Application to dosimetry and microdosimetry. 3 refs., 2 figs

  14. Development of Remote Detection Technique of Radionuclide

    International Nuclear Information System (INIS)

    The object of the research is development of DIAL technique for remote detection of radioactive materials and Doppler lidar technique for measurement of three-dimensional wind field through performance tests. And, development of key technologies based on lidar techniques for practical field applications in the future. ? Development of Dial technology for remote radionuclide detection - Selection of spectral range: differential absorption cross-section > 10-18 cm2 - Empirical test for cell production and study on the detection limit of the optimal experiment - Study on the optimization of measurement signal processing and signal interpretation algorithms. ? Development of Doppler lidar technology for the local wind field - development of frequency feedback and locking system: detection limit 1MHz - Development of Lidar transceiver system and research on operational algorithm - Design of field application system and simulation

  15. Magnetic resonance imaging of living systems by remote detection

    Energy Technology Data Exchange (ETDEWEB)

    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.

  16. The remote atmospheric and ionospheric detection system

    International Nuclear Information System (INIS)

    The Remote Atmospheric and Ionospheric Detection System (RAIDS) experiment, to fly on a TIROS spacecraft in the late 1980's, consists of a comprehensive set of one limb imaging and seven limb scanning optical sensors. These eight instruments span the spectral range from the extreme ultraviolet to the near infrared, allowing simultaneous observations of the neutral and ion composition on the day and night side as well as in the auroral region. The primary objective of RAIDS is to demonstrate a system for remote sensing of the ionosphere to produce global maps of the electron density, peak altitude and critical frequency

  17. Remote detection of explosives using trained canines

    International Nuclear Information System (INIS)

    Use of dogs is a search method which combines high probability of detection, speed of search, and low cost. It was concluded that the canine could be used for explosive screening of personnel, but that it was imperative that the dog be in a position remote from employees and employee traffic. A study was made of the design of booths and air flow for this purpose. Results of tests and conclusions are given and discussed

  18. MRI Helps Detect Brain Bleeding Soon After Traumatic Brain Injury

    Science.gov (United States)

    ... MRI Helps Detect Brain Bleeding Soon After Traumatic Brain Injury Military study suggests patients might get better, more ... undergo brain imaging soon after suffering a traumatic brain injury (TBI) may get better treatment more promptly, a ...

  19. MRI detection of single particles for cellular imaging

    OpenAIRE

    Shapiro, Erik M.; Skrtic, Stanko; Sharer, Kathryn; Hill, Jonathan M.; Dunbar, Cynthia E; Koretsky, Alan P

    2004-01-01

    There is rapid growth in the use of MRI for molecular and cellular imaging. Much of this work relies on the high relaxivity of nanometer-sized, ultrasmall dextran-coated iron oxide particles. Typically, millions of dextran-coated ultrasmall iron oxide particles must be loaded into cells for efficient detection. Here we show that single, micrometer-sized iron oxide particles (MPIOs) can be detected by MRI in vitro in agarose samples, in cultured cells, and in mouse embryos. Experiments studyin...

  20. Feasibility of Detecting Pulmonary Embolism Using Noncontrast MRI

    OpenAIRE

    Mudge, C. S.; Healey, T. T.; Atalay, M. K.; Pezzullo, J. A.

    2013-01-01

    Purpose. The purpose of this study was to evaluate the feasibility of detecting pulmonary emboli utilizing noncontrast magnetic resonance imaging techniques in patients with known pulmonary embolism. Materials and Methods. Eleven patients were enrolled in a study to evaluate right ventricular function by cardiac MRI in patients diagnosed with acute pulmonary embolism on CT pulmonary angiogram. Cardiac MRI was performed as soon as possible following pulmonary embolism detection. Two independen...

  1. Remote sensing for oil spill detection and response

    International Nuclear Information System (INIS)

    This paper focuses on the use of remote sensing for marine oil spill detection and response. The surveillance and monitoring of discharges, and the main elements of effective surveillance are discussed. Tactical emergency response and the requirements for selecting a suitable remote sensing approach, airborne remote sensing systems, and the integration of satellite and airborne imaging are examined. Specifications of satellite surveillance systems potentially usable for oil spill detection, and specifications of airborne remote sensing systems suitable for oil spill detection, monitoring and supplemental actions are tabulated, and a schema of integrated satellite-airborne remote sensing (ISARS) is presented. (UK)

  2. Detectability of MRI Turbulence in Protoplanetary Disks

    Science.gov (United States)

    Teague, Richard; Semenov, Dmitry; Flock, Mario; Henning, Thomas

    2015-08-01

    Protoplanetary disks are the nurseries of planet formation. Within them, turbulence acts as a stirring mechanism, combining the large population of small grains successively into pebbles, planetesimals and eventually planetary cores. There are many tuburbulent mechanisms proposed to fulfil this role, however, current observations are not sufficient to distinguish one mechanism from the other.This poster looks at the hallmarks of magneto-rotational instabilities (MRI), which relies on the coupling of the gas to the magnetic fields of the disk. Previous attempts to determine the electron fraction necessary for MRI to be present are hampered by the lack of atomic ions observed in disks and a large uncertainty when scaling abundance molecualr ions which are readily observed.It has been shown with global-MHD models, however, that MRI turbulence can incite distinct azimuthal dependent strucutres in the gas of the disk. We explore the possibility of identifying this non-Keplerian nature of a disk's kinematical structure and discuss whether, through a mode analysis of the kinematic structure, one can isolate MRI tuburlence from other forms with full ALMA capabilities.

  3. MRI diagnosis of hypertrophic osteoarthropathy from a remote childhood malignancy

    International Nuclear Information System (INIS)

    Hypertrophic osteoarthropathy (HOA) is a clinico-radiological syndrome characterized by digital clubbing, periosteal proliferation, bone pain, synovitis and arthralgia, all of these being commonly symmetrical. It is occasionally associated with nasopharyngeal lymphoepitheliomas and may develop before or after development of lung metastases in these patients. We report a case of a healthy 22-year-old female who presented to our institution with pain and swelling in the thighs and legs. She had a history of childhood nasopharyngeal lymphoepithelioma. Radiographs of the knees were negative. Magnetic resonance imaging (MRI) showed features suggestive of bilateral periostitis. Because of the propensity of the rare childhood nasopharyngeal lymphoepithelioma to present with HOA, this entity was included in the differential diagnosis. A subsequent chest radiograph and CT demonstrated a lung and mediastinal mass that were histologically confirmed to be metastatic. To the best of our knowledge, HOA and metastases from nasopharyngeal lymphoepithelioma occurring after such a long time interval have not been previously reported. Early demonstration and consideration of HOA on the basis of MRI, lead to expeditious and appropriate subsequent investigation. (orig.)

  4. Remote Optical Detection of Alpha Radiation

    International Nuclear Information System (INIS)

    Alpha emitting radiation sources are typically hard to detect with conventional detectors due to the short range of alpha particles in the air. However, previous studies have shown that remote detection of alpha radiation is possible by measuring the ionization-induced fluorescence of air molecules. The alpha-induced ultraviolet (UV) light is mainly emitted by molecular nitrogen and its fluorescence properties are well known. The benefit of this method is the long range of UV photons in the air. Secondly, the detection is possible also under a strong beta and gamma radiation backgrounds as they do not cause localized molecular excitation. In this work, the optical detection was studied using two different detection schemes; spectral separation of fluorescence from the background lighting and coincidence detection of UV photons originating from a single radiative decay event. Our spectrally integrated measurements have shown that one alpha decay event yields up to 400 fluorescence photons in the air and all these UV photons are induced in a 5 ns time-window. On the other hand, the probability of a background coincidence event in 5 ns scale is very rare compared to the number of background photons. This information can be applied in fluorescence coincidence filtering to discriminate the alpha radiation initiated fluorescence signal from much more intense background lighting. A device called HAUVA (Handheld Alpha UV Application) was built during this work for demonstration purposes. HAUVA utilizes spectral filtering and it is designed to detect alpha emitters from a distance of about 40 cm. Using specially selected room lighting, the device is able to separate 1 kBq alpha emitter from the background lighting with 1 second integration time. (author)

  5. DETECTION OF TUMOR IN MRI USING VECTOR QUANTIZATION SEGMENTATION

    Directory of Open Access Journals (Sweden)

    Dr. H. B. Kekre

    2010-08-01

    Full Text Available Magnetic Resonance Imaging (MRI is the state-of-the-art medical imaging technology which allows cross sectional view of the body with unprecedented tissue contrast. MRI plays an important role in assessing pathological conditions of the ankle, foot and brain. It has rapidly evolved into an accepted modality for medical imaging ofdisease processes in the musculoskeletal system, especially the foot and brain due to the use of non-ionizing radiation. MRI provides a digital representation of tissue characteristic that can be obtained in any tissue plane. The images produced by an MRI scanner are best described as slices through the brain. MRI has the added advantage ofbeing able to produce images which slice through the brain in both horizontal and vertical planes. This paper presents a vector quantization segmentation method to detect cancerous mass from MRI images. In order to increase radiologist’s diagnostic performance, computer-aided diagnosis (CAD scheme have been developed to improve the detection of primary signatures of this disease: masses and microcalcifications.

  6. Activation Detection in fMRI Using Jeffrey Divergence

    Science.gov (United States)

    Seghouane, Abd-Krim

    2009-12-01

    A statistical test for detecting activated pixels in functional MRI (fMRI) data is proposed. For the derivation of this test, the fMRI time series measured at each voxel is modeled as the sum of a response signal which arises due to the experimentally controlled activation-baseline pattern, a nuisance component representing effects of no interest, and Gaussian white noise. The test is based on comparing the dimension of the voxels fMRI time series fitted data models with and without controlled activation-baseline pattern. The Jeffrey divergence is used for this comparison. The test has the advantage of not requiring a level of significance or a threshold to be provided.

  7. MRI detection of single particles for cellular imaging

    Science.gov (United States)

    Shapiro, Erik M.; Skrtic, Stanko; Sharer, Kathryn; Hill, Jonathan M.; Dunbar, Cynthia E.; Koretsky, Alan P.

    2004-01-01

    There is rapid growth in the use of MRI for molecular and cellular imaging. Much of this work relies on the high relaxivity of nanometer-sized, ultrasmall dextran-coated iron oxide particles. Typically, millions of dextran-coated ultrasmall iron oxide particles must be loaded into cells for efficient detection. Here we show that single, micrometer-sized iron oxide particles (MPIOs) can be detected by MRI in vitro in agarose samples, in cultured cells, and in mouse embryos. Experiments studying effects of MRI resolution and particle size from 0.76 to 1.63 ?m indicated that \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} \\begin{equation*}{\\mathrm{T}}_{2}^{*}\\end{equation*}\\end{document} effects can be readily detected from single MPIOs at 50-?m resolution and significant signal effects could be detected at resolutions as low as 200 ?m. Cultured cells were labeled with fluorescent MPIOs such that single particles were present in individual cells. These single particles in single cells could be detected both by MRI and fluorescence microscopy. Finally, single particles injected into single-cell-stage mouse embryos could be detected at embryonic day 11.5, demonstrating that even after many cell divisions, daughter cells still carry individual particles. These results demonstrate that MRI can detect single particles and indicate that single-particle detection will be useful for cellular imaging. PMID:15256592

  8. Automated detection of multiple sclerosis lesions in serial brain MRI

    Energy Technology Data Exchange (ETDEWEB)

    Llado, Xavier; Ganiler, Onur; Oliver, Arnau; Marti, Robert; Freixenet, Jordi [University of Girona, Computer Vision and Robotics Group, Girona (Spain); Valls, Laia [Dr. Josep Trueta University Hospital, Department of Radiology, Girona (Spain); Vilanova, Joan C. [Girona Magnetic Resonance Center, Girona (Spain); Ramio-Torrenta, Lluis [Dr. Josep Trueta University Hospital, Institut d' Investigacio Biomedica de Girona, Multiple Sclerosis and Neuroimmunology Unit, Girona (Spain); Rovira, Alex [Vall d' Hebron University Hospital, Magnetic Resonance Unit, Department of Radiology, Barcelona (Spain)

    2012-08-15

    Multiple sclerosis (MS) is a serious disease typically occurring in the brain whose diagnosis and efficacy of treatment monitoring are vital. Magnetic resonance imaging (MRI) is frequently used in serial brain imaging due to the rich and detailed information provided. Time-series analysis of images is widely used for MS diagnosis and patient follow-up. However, conventional manual methods are time-consuming, subjective, and error-prone. Thus, the development of automated techniques for the detection and quantification of MS lesions is a major challenge. This paper presents an up-to-date review of the approaches which deal with the time-series analysis of brain MRI for detecting active MS lesions and quantifying lesion load change. We provide a comprehensive reference source for researchers in which several approaches to change detection and quantification of MS lesions are investigated and classified. We also analyze the results provided by the approaches, discuss open problems, and point out possible future trends. Lesion detection approaches are required for the detection of static lesions and for diagnostic purposes, while either quantification of detected lesions or change detection algorithms are needed to follow up MS patients. However, there is not yet a single approach that can emerge as a standard for the clinical practice, automatically providing an accurate MS lesion evolution quantification. Future trends will focus on combining the lesion detection in single studies with the analysis of the change detection in serial MRI. (orig.)

  9. Automated detection of multiple sclerosis lesions in serial brain MRI

    International Nuclear Information System (INIS)

    Multiple sclerosis (MS) is a serious disease typically occurring in the brain whose diagnosis and efficacy of treatment monitoring are vital. Magnetic resonance imaging (MRI) is frequently used in serial brain imaging due to the rich and detailed information provided. Time-series analysis of images is widely used for MS diagnosis and patient follow-up. However, conventional manual methods are time-consuming, subjective, and error-prone. Thus, the development of automated techniques for the detection and quantification of MS lesions is a major challenge. This paper presents an up-to-date review of the approaches which deal with the time-series analysis of brain MRI for detecting active MS lesions and quantifying lesion load change. We provide a comprehensive reference source for researchers in which several approaches to change detection and quantification of MS lesions are investigated and classified. We also analyze the results provided by the approaches, discuss open problems, and point out possible future trends. Lesion detection approaches are required for the detection of static lesions and for diagnostic purposes, while either quantification of detected lesions or change detection algorithms are needed to follow up MS patients. However, there is not yet a single approach that can emerge as a standard for the clinical practice, automatically providing an accurate MS lesion evolution quantification. Future trends will focus on combining the lesion detection in single studies with the analysis of the change detection in serial MRI. (orig.)

  10. Remotely Detectable Biosignatures of Anoxygenic Phototrophs

    Science.gov (United States)

    Parenteau, M. N.; Kiang, N. Y.; Blankenship, R. E.; Sanromá, E.; Palle Bago, E.; Hoehler, T. M.; Pierson, B. K.

    2014-12-01

    Many astrobiological/exobiological studies have been directed at searching for evidence of life on planetary bodies within our solar system, but the search for life does not have to be restricted to our stellar neighborhood. The field of exoplanet research has grown rapidly over the last several years. Studies have moved beyond detection to assessing the habitability and biosignatures of these worlds. The biosignatures considered thus far focus on biogenic gases and planetary surface features, such as the light reflected from the surface of plants to generate the "red edge" of vegetation. Much work has focused on detecting biosignatures of higher life forms (vegetation) on exoplanets. However, land plants only appeared on the Earth 450 million years ago, and required a long path of photosynthetic evolution. There is a dearth of studies examining how light might interact with much simpler, more evolutionarily ancient pigmented communities, such as photosynthetic microbes. These anoxygenic phototrophs, which have inhabited Earth for nearly 80% of its history, may dominate exoplanets at a similar stage of evolution as the Archean or Paleoproterozoic Earth. Similar to the remotely detectable "red edge" of chlorophyll a - containing vegetation, we measured the reflectance spectra of pure cultures and environmental samples of purple sulfur, purple non-sulfur, heliobacteria, green sulfur, and green non-sulfur anoxygenic phototrophs. We observed an increase in reflectivity just past the absorption maximum for the bacteriochlorophyll pigments. Since this reflectance feature is shifted into the NIR compared to that of the red edge of vegetation, we're calling this the "NIR edge" of anoxygenic phototrophs. The bacteriochlorophyll pigments are particularly well suited to absorb the far-red and near-infrared radiation emitted by M dwarf stars, the most common type of star in our galaxy. Therefore these phototrophs serve as model organisms for photosynthesis adapted to alternative spectral environments.

  11. Stress cine MRI for detection of coronary artery disease

    International Nuclear Information System (INIS)

    Stress testing is the cornerstone in the diagnosis of patients with suspected coronary artery disease (CAD). Stress echocardiography has become a well-established modality for the detection of ischemia-induced wall motion abnormalities. However, display and reliable interpretation of stress echocardiography studies are user-dependent, the test reproducibility is low, and 10 to 15% of patients yield suboptimal or non-diagnostic images. Due to its high spatial and contrast resolution, MRI is known to permit an accurate determination of left ventricular function and wall thickness at rest. Early stress MRI studies provided promising results with respect to the detection of CAD. However, the clinical impact was limited due to long imaging time and problematic patient monitoring in the MRI environment. Recent technical improvements - namely ultrafast MR image acquisition - led to a significant reduction of imaging time and improved patient safety. Stress can be induced by physical exercise or pharmacologically by administration of a beta1-agonist (dobutamine) or vasodilatator (dipyridamole and adenosine). The best developed and most promising stress MRI technique is a high-dose dobutamine/atropine stress protocol (10, 20, 30, 40 ?g/kg/min; optionally 0.25-mg fractions of atropine up to maximal dose 1 mg). Severe complications (myocardial infarction, ventricular fibrillation and sustained tachycardia, cardiogenic shock) may be expected in 0.25% of patients. Currently, data of three high-dose dobutamine stress MRI studies are available, revealing a good sensitivity (83 - 87%) and specificity (83 - 86%) in the assessment of CAD. The direct comparison between echocardiography and MRI for the detection of stress-induced wall motion abnormalities yielded better results for dobutamine-MRI in terms of sensitivity (86.2% vs. 74.3%; p < 0.05) and specificity (85.7% vs. 69.8% p < 0.05) as compared to dobutamine stress echocardiography. The superior results of MRI can mainly be explained by the better image quality with sharp delineation of the endocardial and epicardial borders. Currently, stress MRI is already a realistic clinical alternative for the non-invasive assessment of CAD in patients with impaired image quality in echocardiography. (orig.)

  12. Detection and size of pulmonary lesions: how accurate is MRI? A prospective comparison of CT and MRI

    International Nuclear Information System (INIS)

    Background. Although CT is the modality of choice for morphological lung imaging, an increasing proportion of chest imaging is performed by MRI due to the utilization of whole-body MRI. Therefore, the diagnostic performance of MRI in reliably detecting pulmonary lesions should be established. Purpose. To investigate the detection rate of pulmonary lesions by MRI that can be expected in a clinical setting and to assess the accuracy of lesion measurement by MRI compared to CT. Material and Methods. Twenty-eight patients (median age 66 years) with indication for CT imaging due to suspected thoracic malignancy were prospectively included. Chest MRI performed on the same day as CT, comprised unenhanced TrueFisp, ecg-gated T2-weighted HASTE, T1-weighted VIBE, and contrast-enhanced T1-weighted, fat-saturated VIBE sequences. MR sequences were evaluated for lesion detection by two readers independently and measurement of lesion size was performed. MR findings were correlated with CT. Results. One hundred and eight pulmonary lesions (20 thoracic malignancies, 88 lung nodules) were detected by CT in 26 patients. Lesions were ruled out in two patients. All thoracic malignancies were identified by MRI with strong correlation (r 0.97-0.99; P 1 cm in diameter. If a lung lesion is detected by MRI, it is a reliable finding and its measurement is accurate. CT remains superior in detecting small lung nodules (<6 mm). Detection rate of MRI for small lesions is improved using a multi-sequence protocol including contrast administration

  13. Unsupervised-learning airplane detection in remote sensing images

    Science.gov (United States)

    Zhang, Wenjie; Lv, Wu; Zhang, Yifei; Tian, Jinwen; Ma, Jie

    2015-12-01

    This paper attempts to develop an unsupervised learning approach for airplane detection in remote sensing images. This novel airplane detection method is based on circle-frequency filter and cluster-based co-saliency detection. Firstly, the CF-filter method is utilized as the coarse detection to detect target airplanes with some false alarms. Then, we collect all the detected targets and use cluster-based co-saliency detection to enhance the real airplanes and weaken the false alarms, so that most of the false alarms can be eliminated. Experimental results on real remote sensing images demonstrate the efficiency and accuracy of the proposed method.

  14. Fast and direct detection of neuronal activation with diffusion MRI

    International Nuclear Information System (INIS)

    Over the last 30 years functional neuroimaging has emerged as a revolutionary path to study the brain and the mind. This has been possible because of significant advances mainly in two imaging modalities, namely Positron Emission Tomograph y (PET) and Magnetic Resonance Imaging (MRI). Amazingly, although those two modalities are based on radically different physical approaches (detection of 1 3 radioactivity for the first one and nuclear magnetization for the second), both allo w brain activation images to be obtained through measurements involving water molecules. So far, PET and MRI functional imaging have relied on the same principle that neuronal activation and blood flow are coupled through metabolism: Blood flow increases locally in activated brain regions. In the case of PET one uses H2O radioactive water which is produced by using a cyclotron and injected to the subject vasculature. In activated brain regions the increase in blood flow leads to a local increase in the tissue radioactive water content detected and localized by the PE T camera. With MRI the hydrogen nuclei of brain endogenous water molecules are magnetized by a strong external magnetic field. In activated regions the increase in blood flow results in an increase of blood oxygenation which induces a slight perturbation of the magnetization relaxation properties of the water molecules around blood vessels detected by the MRI scanner (so called 'BOLD' effect). I n both approaches water is, thus, merely an indirect means to look at changes in cerebral blood flow which accompany brain activation, and although PET and BOLD f MRI have been extremely successful for the functional neuroimaging community, present well known limitations. While the coupling between neuronal activation, metabolism and blood flow has been verified in most instances including BOLD f MRI, the degree and the mechanism of coupling remains largely debated (Magistratt, Pellerin, Mangia) and may fail in some pathological conditions or in the presence of drugs. Also, it has been pointed out that the spatial functional resolution of vascular based functional neuroimaging might be limited, because vessels responsible for the increase of blood flow and blood volume feed or drain somewhat large territories which include clusters of neurons with potentially different functions. Similarly the physiological delay necessary for the mechanisms triggering the vascular response to work intrinsically limits the temporal resolution of BOLD f MRI. On the other hand, a fundamentally new paradigm is being proposed to look at brain activity through the observation with MRI of the diffusion behavior of the water molecules. It has been shown that the diffusion of water slightly slows down during brain activation. This slowdown, which occurs several seconds before the hemodynamic response detected by BOLD f MRI, has been described in terms of a phase transition of the water molecules in the cells undergoing activation and tentatively attributed to the swelling of those cells. This finding marks a significant departure from the former blood flow based PET and MRI approaches, and potentially offers improved spatial and temporal resolution, because the proposed mechanism appears more intimately linked to neuronal activation. However, the step might even extend further: Contrarily to the former approaches based on changes in artificially induced water physical properties, namely radioactivity and magnetization, required for the external PET or MR I detection, the new, diffusion based approach, merely uses MRI as a means to reveal changes in intrinsic water physical properties. These changes in the diffusion behaviour of water during activation seem to belong to an endogenous part of the activation process, and perhaps even more, could be an active component of this process that evolution has capitalized upon. The aim of this presentation is to review our current knowledge on the water physical properties i n biological tissues, which could be relevant to diffusion f MRI, and to review the biophysical mechanism

  15. Detection of brain metastases from lung cancer by CT and MRI

    International Nuclear Information System (INIS)

    To compare the detectability of brain metastases from lung cancer, both CT and MRI were performed on all patients. Thirty-two lung cancer patients with brain metastases admitted from December 1990 to June 1994 were examined by CT and MRI using contrast enhancement. Six radiologists individually evaluated CT and MRI films for brain metastases. In 3 of 32 cases, multiple small metastatic lesions which could not be detected on CT were detected on MRI. In 29 of the 32 cases, 56 metastatic lesions were detected on CT, whereas 103 lesions were detected on MRI. There were no lesions that were detected only by CT and were not detected by MRI. MRI was superior to CT for determining small lesions less than 9 mm and inferior tentorial lesions. As a result, we consider that CT is not sufficiently effective for detecting brain metastases of lung cancer, and that MRI is now indispensable. (author)

  16. White matter injury detection in neonatal MRI

    Science.gov (United States)

    Cheng, Irene; Hajari, Nasim; Firouzmanesh, Amirhossein; Shen, Rui; Miller, Steven; Poskitt, Ken; Basu, Anup

    2013-02-01

    Early detection of white matter injury in premature newborns can facilitate timely clinical treatments reducing the potential risk of later developmental deficits. It was reported that there were more than 5% premature newborns in British Columbia, Canada, among which 5-10% exhibited major motor deficits and 25-50% exhibited significant developmental and visual deficits. With the advancement of computer assisted detection systems, it is possible to automatically identify white matter injuries, which are found inside the grey matter region of the brain. Atlas registration has been suggested in the literature to distinguish grey matter from the soft tissues inside the skull. However, our subjects are premature newborns delivered at 24 to 32 weeks of gestation. During this period, the grey matter undergoes rapid changes and differs significantly from one to another. Besides, not all detected white spots represent injuries. Additional neighborhood information and expert input are required for verification. In this paper, we propose a white matter feature identification system for premature newborns, which is composed of several steps: (1) Candidate white matter segmentation; (2) Feature extraction from candidates; (3) Validation with data obtained at a later stage on the children; and (4) Feature confirmation for automated detection. The main challenge of this work lies in segmenting white matter injuries from noisy and low resolution data. Our approach integrates image fusion and contrast enhancement together with a fuzzy segmentation technique to achieve promising results. Other applications, such as brain tumor and intra-ventricular haemorrhage detection can also benefit from our approach.

  17. Squid detected NMR and MRI at ultralow fields

    Science.gov (United States)

    Clarke, John (Berkeley, CA); Pines, Alexander (Berkeley, CA); McDermott, Robert F. (Monona, WI); Trabesinger, Andreas H. (London, GB)

    2008-12-16

    Nuclear magnetic resonance (NMR) signals are detected in microtesla fields. Prepolarization in millitesla fields is followed by detection with an untuned dc superconducting quantum interference device (SQUID) magnetometer. Because the sensitivity of the SQUID is frequency independent, both signal-to-noise ratio (SNR) and spectral resolution are enhanced by detecting the NMR signal in extremely low magnetic fields, where the NMR lines become very narrow even for grossly inhomogeneous measurement fields. MRI in ultralow magnetic field is based on the NMR at ultralow fields. Gradient magnetic fields are applied, and images are constructed from the detected NMR signals.

  18. Remote detection of chemicals with passive millimeter waves.

    Energy Technology Data Exchange (ETDEWEB)

    Gopalsami, N.; Bakhtiari, S.; Elmer, T. W.; Raptis, A. C.; Nuclear Engineering Division

    2006-01-01

    Passive millimeter-wave (mmW) systems have been used in the past to remotely map solid targets and to measure low-pressure spectral lines of stratospheric and interstellar gases; however, its application to pressure-broadened spectral detection of terrestrial gases is new. A radiative transfer model was developed to determine the detection feasibility and system requirements for passive mmW spectral detection. A Dicke-switched multispectral radiometer that operates at 146-154 GHz was designed and built for remote detection of stack gases. The radiometer was tested in the laboratory using a gas cell; the spectra of acetonitrile were detected passively against a cold background, which mimicked typical remote detection scenarios in the field. With Dicke-switched integration of radiometric signals, on-line calibration, and novel signal processing to minimize atmospheric fluctuation, spectral line detection of polar molecules is possible from chemical plumes a few kilometers away.

  19. Diffusion-weighted MRI provides additional value to conventional dynamic contrast-enhanced MRI for detection of hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Vandecaveye, Vincent; Keyzer, Frederik de; Op de Beeck, Katya; Roebben, Ilse; Bielen, Didier; Dymarkowski, Steven [University Hospitals Leuven, Department of Radiology, Leuven (Belgium); Verslype, Chris; Nevens, Frederik [University Hospitals Leuven, Department of Hepatology, Leuven (Belgium); Komuta, Mina; Roskams, Tania [University Hospitals Leuven, Department of Pathology, Leuven (Belgium); Topal, Baki [University Hospitals Leuven, Department of Abdominal Surgery, Leuven (Belgium)

    2009-10-15

    The purpose of this study was to evaluate the accuracy of diffusion-weighted magnetic resonance imaging (DW-MRI) in differentiating HCC from benign cirrhotic lesions compared with conventional dynamic contrast-enhanced MRI. Fifty-five patients with cirrhosis underwent conventional and DW-MRI at 1.5 Tesla. Signal intensity ratios (SI{sub ratio}) of solid liver lesions to adjacent hepatic parenchyma were measured for b0, b100, b600 and b1000, and the apparent diffusion coefficients (ADC) were calculated. In 27 patients, imaging results were compared to histopathology, and in 28 patients, to imaging follow-up. Based on predetermined thresholds, sensitivity and specificity of DW-MRI and conventional MRI were compared. SI{sub ratio} was significantly different between malignant and benign lesions at all b-values (P<0.0001). No significant difference in ADC was seen (P = 0.47). For detection of malignant lesions, DW-MRI with b600-SI{sub ratio} yielded a sensitivity of 95.2% compared to 80.6% for conventional MRI (P = 0.023) and a specificity of 82.7% compared to 65.4% (P=0.064). The improved accuracy was most beneficial for differentiating malignant lesions smaller than 2 cm. DW-MRI with b600-SI{sub ratio} improved the detection of small HCC and the differentiation of pseudotumoral lesions compared with conventional MRI. (orig.)

  20. Sensitivity of MRI in detecting alveolar infiltrates. Experimental studies

    International Nuclear Information System (INIS)

    Purpose: An experimental study using porcine lung explants and a dedicated chest phantom to evaluate the signal intensity of artificial alveolar infiltrates with T1- and T2-weighted MRI sequences. Material and Methods: 10 porcine lung explants were intubated, transferred into the cavity of a MRI-compatible chest phantom and inflated by continuous evacuation of the artificial pleural space. All lungs were examined with MRI at 1.5 T before and after intra-tracheal instillation of either 100 or 200 ml gelatine-stabilised liquid to simulate alveolar infiltrates. MR-examination comprised gradient echo (2D- and 3D-GRE) and fast spin echo sequences (T2-TSE and T2-HASTE). The signal intensity of lung parenchyma was evaluated at representative cross sections using a standardised scheme. Control studies were acquired with helical CT. Results: The instilled liquid caused patchy confluent alveolar infiltrates resembling the findings in patients with pneumonia or ARDS. CT revealed typical ground-glass opacities. Before the application of the liquid, only T2-HASTE and T2-TSE displayed lung parenchyma signals with a signal/noise ratio of 3.62 and 1.39, respectively. After application of the liquid, both T2-weighted sequences showed clearly visible infiltrates with an increase in signal intensity of approx. 30% at 100 ml (p2-weighted sequences detects artificial alveolar infiltrates with high signal intensity and may be a highly sensitive tool to detect pneumonia in patients. (orig.)

  1. Automated detection of periventricular veins on 7 T brain MRI

    Science.gov (United States)

    Kuijf, Hugo J.; Bouvy, Willem H.; Zwanenburg, Jaco J. M.; Viergever, Max A.; Biessels, Geert Jan; Vincken, Koen L.

    2015-03-01

    Cerebral small vessel disease is common in elderly persons and a leading cause of cognitive decline, dementia, and acute stroke. With the introduction of ultra-high field strength 7.0T MRI, it is possible to visualize small vessels in the brain. In this work, a proof-of-principle study is conducted to assess the feasibility of automatically detecting periventricular veins. Periventricular veins are organized in a fan-pattern and drain venous blood from the brain towards the caudate vein of Schlesinger, which is situated along the lateral ventricles. Just outside this vein, a region-of- interest (ROI) through which all periventricular veins must cross is defined. Within this ROI, a combination of the vesselness filter, tubular tracking, and hysteresis thresholding is applied to locate periventricular veins. All detected locations were evaluated by an expert human observer. The results showed a positive predictive value of 88% and a sensitivity of 95% for detecting periventricular veins. The proposed method shows good results in detecting periventricular veins in the brain on 7.0T MR images. Compared to previous works, that only use a 1D or 2D ROI and limited image processing, our work presents a more comprehensive definition of the ROI, advanced image processing techniques to detect periventricular veins, and a quantitative analysis of the performance. The results of this proof-of-principle study are promising and will be used to assess periventricular veins on 7.0T brain MRI.

  2. Comparison of MRI and endoscope ultrasound detection in preoperative T/N staging of gastric cancer

    OpenAIRE

    Lei, Cui; HUANG, LIMING; Yanlin WANG; HUANG, YILING; Huang, Yurong

    2013-01-01

    Gastric cancer is a common malignancy and cause of mortality. The aim of this study was to evaluate the accuracy of magnetic resonance imaging (MRI) and endoscopic ultrasound (EUS) detection in preoperative clinical T/N staging in gastric cancer. Thirty-eight patients diagnosed with gastric cancer by gastroscopy and pathological examination were included in the study. All 38 patients underwent MRI and EUS detection prior to surgery. The accuracy of MRI, EUS and MRI+EUS was evaluated according...

  3. Target Detection: Remote Sensing Techniques for Defence Applications

    Directory of Open Access Journals (Sweden)

    B. B. Chaudhuri

    1995-10-01

    Full Text Available The tremendous development in remote sensing technology in the recent past has opened up new challenges in defence applications. On important area of such applications is in target detection. This paper describes both classical and newly developed approaches to detect the targets by using remotely-sensed digital images. The classical approach includes statistical classification methods and image processing techniques. The new approach deals with a relatively new sensor technology, namely, synthetic aperture radar (SAR systems and fast developing tools, like neural networks and multisource data integration for analysis and interpretation. With SAR images, it is possible to detect targets or features of a target that is otherwise not possible. Neural networks and multisource data integration tools also have a great potential in analysing and interpreting remote sensing data for target detection.

  4. Detect Natural Hazard Prone Areas Remote Way

    Science.gov (United States)

    Ren, D.; Hong, Y.; Shen, X.; Lynch, M. J.; Zhang, G.

    2014-12-01

    Our society has faced a steep rise in economic and insured losses from natural hazards, especially weather related. Natural hazards in mountainous regions are closely related to the chute system diatribution and underground channels. Bedrock crevasses are not easy to measure because they are often overlain by the rhizosphere. In this presentation, we will present remote sensing imageries that are indicative of bedrock crack changes. In particular, we examined four 5x5 degree grid boxes surrounding respectively El Chichon, Mt. St. Helens, Mt. Pinatubo and Mt. Fuji. It is found that surrounding the Fuji mountains, ground water increases from 2002-2013 are out of natural sync with precipitation and other indirect indications of bedrock cracks. So, the increase of natural hazard of this region is expected to be more frequent in the upcoming several years

  5. Detecting link failures in complex network processes using remote monitoring

    Science.gov (United States)

    Dhal, R.; Abad Torres, J.; Roy, S.

    2015-11-01

    We study whether local structural changes in a complex network can be distinguished from passive remote time-course measurements of the network's dynamics. Specifically the detection of link failures in a network synchronization process from noisy measurements at a single network component is considered. By phrasing the detection task as a Maximum A Posteriori Probability hypothesis testing problem, we are able to obtain conditions under which the detection is (1) improved over the a priori and (2) asymptotically perfect, in terms of the network spectrum and graph. We find that, in the case where the detector has knowledge of the network's state, perfect detection is possible under general connectivity conditions regardless of the measurement location. When the detector does not have state knowledge, a remote signature permits improved but not perfect detection, under the same connectivity conditions. At its essence, detectability is achieved because of the close connection between a network's topology, its eigenvalues and local response characteristics.

  6. Differential Geometric Approach to Change Detection Using Remotely Sensed Images

    Directory of Open Access Journals (Sweden)

    N Panigrahi

    2011-08-01

    Full Text Available Change Detection using multi-temporal satellite images of same area is an established as well as actively pursued research problem. Most of the change detection techniques use algebraic or transform methods to do a pixel by pixel comparison of change detection. These techniques heavily depend upon the correct choice of threshold value to segregate the real changed pixels from the apparent changed ones. Also all these techniques can only compute the two dimensional change of the terrain surface from remotely sensed data. In this paper we propose a differential geometry approach to detect changes from remotely sensed images, which can detect the change using the geometric property of the pixels with respect to its surroundings. It can compute and filter the changed pixels having high curvature from that of flat (2D changed pixels.

  7. Remotely detected differential pulse transit time as a stress indicator

    Science.gov (United States)

    Kaur, Balvinder; Tarbox, Elizabeth; Cissel, Marty; Moses, Sophia; Luthra, Megha; Vaidya, Misha; Tran, Nhien; Ikonomidou, Vasiliki N.

    2015-05-01

    The human cardiovascular system, controlled by the autonomic nervous system (ANS), is one of the first sites where one can see the "fight-or-flight" response due to the presence of external stressors. In this paper, we investigate the possibility of detecting mental stress using a novel measure that can be measured in a contactless manner: Pulse transit time (dPTT), which refers to the time that is required for the blood wave (BW) to cover the distance from the heart to a defined remote location in the body. Loosely related to blood pressure, PTT is a measure of blood velocity, and is also implicated in the "fight-or-flight" response. We define the differential PTT (dPTT) as the difference in PTT between two remote areas of the body, such as the forehead and the palm. Expanding our previous work on remote BW detection from visible spectrum videos, we built a system that remotely measures dPTT. Human subject data were collected under an IRB approved protocol from 15 subjects both under normal and stress states and are used to initially establish the potential use of remote dPPT detection as a stress indicator.

  8. Hemorrhage detection in MRI brain images using images features

    Science.gov (United States)

    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.

  9. Diffusion-weighted MRI provides additional value to conventional dynamic contrast-enhanced MRI for detection of hepatocellular carcinoma

    International Nuclear Information System (INIS)

    The purpose of this study was to evaluate the accuracy of diffusion-weighted magnetic resonance imaging (DW-MRI) in differentiating HCC from benign cirrhotic lesions compared with conventional dynamic contrast-enhanced MRI. Fifty-five patients with cirrhosis underwent conventional and DW-MRI at 1.5 Tesla. Signal intensity ratios (SIratio) of solid liver lesions to adjacent hepatic parenchyma were measured for b0, b100, b600 and b1000, and the apparent diffusion coefficients (ADC) were calculated. In 27 patients, imaging results were compared to histopathology, and in 28 patients, to imaging follow-up. Based on predetermined thresholds, sensitivity and specificity of DW-MRI and conventional MRI were compared. SIratio was significantly different between malignant and benign lesions at all b-values (Pratio yielded a sensitivity of 95.2% compared to 80.6% for conventional MRI (P = 0.023) and a specificity of 82.7% compared to 65.4% (P=0.064). The improved accuracy was most beneficial for differentiating malignant lesions smaller than 2 cm. DW-MRI with b600-SIratio improved the detection of small HCC and the differentiation of pseudotumoral lesions compared with conventional MRI. (orig.)

  10. Acutely unstable cervical spine injury with normal CT scan findings: MRI detects ligamentous injury.

    Science.gov (United States)

    Erwood, Andrew M; Abel, Taylor J; Grossbach, Andrew J; Ahmed, Raheel; Dahdaleh, Nader S; Dlouhy, Brian J

    2016-02-01

    MRI can detect ligamentous injury not detectable with CT scan. The authors present a trauma patient with normal CT imaging despite dislocation on standing radiograph. MRI detected disruption of the C5-C6 posterior ligamentous complex that requires surgery. PMID:26601812

  11. Discovery Radiomics for Multi-Parametric MRI Prostate Cancer Detection

    CERN Document Server

    Chung, Audrey G; Kumar, Devinder; Khalvati, Farzad; Haider, Masoom A; Wong, Alexander

    2015-01-01

    Prostate cancer is the most diagnosed form of cancer in Canadian men, and is the third leading cause of cancer death. Despite these statistics, prognosis is relatively good with a sufficiently early diagnosis, making fast and reliable prostate cancer detection crucial. As imaging-based prostate cancer screening, such as magnetic resonance imaging (MRI), requires an experienced medical professional to extensively review the data and perform a diagnosis, radiomics-driven methods help streamline the process and has the potential to significantly improve diagnostic accuracy and efficiency, and thus improving patient survival rates. These radiomics-driven methods currently rely on hand-crafted sets of quantitative imaging-based features, which are selected manually and can limit their ability to fully characterize unique prostate cancer tumour phenotype. In this study, we propose a novel \\textit{discovery radiomics} framework for generating custom radiomic sequences tailored for prostate cancer detection. Discover...

  12. The method of active remote detection of nuclear ammunition

    International Nuclear Information System (INIS)

    Method for active nondestructive detection of nuclear ammunition on mobile or remote objects with application of powerful pulse neutron generator of intermediate energy as a mean for control of in international agreements observance relative to nuclear arms reduction is proposed. Numerical modelling of the proposed method is carried out. 10 refs., 1 fig., 2 tabs

  13. Sensitive change detection for remote sensing monitoring of nuclear treaties

    DEFF Research Database (Denmark)

    Canty, Morton J.; Nielsen, Allan Aasbjerg; Schlittenhardt, Jörg

    2005-01-01

    Triggered in part by the advent of high resolution commercial optical satellites, the analysis of open-source satellite imagery has now established itself as an important tool for monitoring nuclear activities throughout the world (Chitumbo et al 2001). Whereas detection of land cover and land use change is a commonplace application in remote sensing, the detection of anthropogenic changes associated with nuclear activities, whether declared or clandestine, presents a difficult challenge. It is ...

  14. SQUID-Detected In Vivo MRI at Microtesla Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Moble, Michael; Myers, Whittier R; Lee, SeungKyun; Kelso, Nathan; Hatridge, Michael; Pines, Alexander; Clarke, John

    2005-06-01

    We use a low transition temperature (T{sub c}) Super-conducting Quantum Interference Device (SQUID) to perform in vivo magnetic resonance imaging (MRI) at magnetic fields around 100 microtesla, corresponding to proton Larmor frequencies of about 5 kHz. In such low fields, broadening of the nuclear magnetic resonance lines due to inhomogeneous magnetic fields and susceptibility variations of the sample are minimized, enabling us to obtain high quality images. To reduce environmental noise the signal is detected by a second-order gradiometer, coupled to the SQUID, and the experiment is surrounded by a 3-mm thick Al shield. To increase the signal-to-noise ratio (SNR), we prepolarize the samples in a field up to 100 mT. Three-dimensional images are acquired in less than 6 minutes with a standard spin-echo phase-encoding sequence. Using encoding gradients of {approx}100 {micro}T/m we obtain three-dimensional images of bell peppers with a resolution of 2 x 2 x 8 mm{sup 3}. Our system is ideally suited to acquiring images of small, peripheral parts of the human body such as hands and arms. In vivo images of an arm, acquired at 132 {micro}T, show 24-mm sections of the forearm with a resolution of 3 x 3 mm{sup 2} and a SNR of 10. We discuss possible applications of MRI at these low magnetic fields.

  15. SQUID-Detected In Vivo MRI at Microtesla Magnetic Fields

    International Nuclear Information System (INIS)

    We use a low transition temperature (Tc) Super-conducting Quantum Interference Device (SQUID) to perform in vivo magnetic resonance imaging (MRI) at magnetic fields around 100 microtesla, corresponding to proton Larmor frequencies of about 5 kHz. In such low fields, broadening of the nuclear magnetic resonance lines due to inhomogeneous magnetic fields and susceptibility variations of the sample are minimized, enabling us to obtain high quality images. To reduce environmental noise the signal is detected by a second-order gradiometer, coupled to the SQUID, and the experiment is surrounded by a 3-mm thick Al shield. To increase the signal-to-noise ratio (SNR), we prepolarize the samples in a field up to 100 mT. Three-dimensional images are acquired in less than 6 minutes with a standard spin-echo phase-encoding sequence. Using encoding gradients of ?100 (micro)T/m we obtain three-dimensional images of bell peppers with a resolution of 2 x 2 x 8 mm3. Our system is ideally suited to acquiring images of small, peripheral parts of the human body such as hands and arms. In vivo images of an arm, acquired at 132 (micro)T, show 24-mm sections of the forearm with a resolution of 3 x 3 mm2 and a SNR of 10. We discuss possible applications of MRI at these low magnetic fields

  16. Diagnostic imaging strategy for MDCT- or MRI-detected breast lesions: use of targeted sonography

    International Nuclear Information System (INIS)

    Leading-edge technology such as magnetic resonance imaging (MRI) or computed tomography (CT) often reveals mammographically and ultrasonographically occult lesions. MRI is a well-documented, effective tool to evaluate these lesions; however, the detection rate of targeted sonography varies for MRI detected lesions, and its significance is not well established in diagnostic strategy of MRI detected lesions. We assessed the utility of targeted sonography for multidetector-row CT (MDCT)- or MRI-detected lesions in practice. We retrospectively reviewed 695 patients with newly diagnosed breast cancer who were candidates for breast conserving surgery and underwent MDCT or MRI in our hospital between January 2004 and March 2011. Targeted sonography was performed in all MDCT- or MRI-detected lesions followed by imaging-guided biopsy. Patient background, histopathology features and the sizes of the lesions were compared among benign, malignant and follow-up groups. Of the 695 patients, 61 lesions in 56 patients were detected by MDCT or MRI. The MDCT- or MRI-detected lesions were identified by targeted sonography in 58 out of 61 lesions (95.1%). Patients with pathological diagnoses were significantly older and more likely to be postmenopausal than the follow-up patients. Pathological diagnosis proved to be benign in 20 cases and malignant in 25. The remaining 16 lesions have been followed up. Lesion size and shape were not significantly different among the benign, malignant and follow-up groups. Approximately 95% of MDCT- or MRI-detected lesions were identified by targeted sonography, and nearly half of these lesions were pathologically proven malignancies in this study. Targeted sonography is a useful modality for MDCT- or MRI-detected breast lesions

  17. The Remote Detection of Alpha-Radioactive Nucleus Decay

    Science.gov (United States)

    Gurkovskiy, Boris; Miroshnichenko, Vladimir; Onishchenko, Evgeny; Simakov, Andrey; Streil, Thomas

    Results of the new device design for the alpha-radiation remote detection are presented. Negative ions from the alpha particle tracks are detected by the discharge wire counter opened to air. Ion clusters being transferred from the particle tracks to the detector volume by an air flux. The detector works in a counting mode that provides sharp selectivity and accuracy of measurements. The basic parameters of the device are: detecting distance -0.5 m; measurement time -30 s; the square sensitivity -0.05 Bq/cm2.

  18. Automatic brain tumor detection in MRI: methodology and statistical validation

    Science.gov (United States)

    Iftekharuddin, Khan M.; Islam, Mohammad A.; Shaik, Jahangheer; Parra, Carlos; Ogg, Robert

    2005-04-01

    Automated brain tumor segmentation and detection are immensely important in medical diagnostics because it provides information associated to anatomical structures as well as potential abnormal tissue necessary to delineate appropriate surgical planning. In this work, we propose a novel automated brain tumor segmentation technique based on multiresolution texture information that combines fractal Brownian motion (fBm) and wavelet multiresolution analysis. Our wavelet-fractal technique combines the excellent multiresolution localization property of wavelets to texture extraction of fractal. We prove the efficacy of our technique by successfully segmenting pediatric brain MR images (MRIs) from St. Jude Children"s Research Hospital. We use self-organizing map (SOM) as our clustering tool wherein we exploit both pixel intensity and multiresolution texture features to obtain segmented tumor. Our test results show that our technique successfully segments abnormal brain tissues in a set of T1 images. In the next step, we design a classifier using Feed-Forward (FF) neural network to statistically validate the presence of tumor in MRI using both the multiresolution texture and the pixel intensity features. We estimate the corresponding receiver operating curve (ROC) based on the findings of true positive fractions and false positive fractions estimated from our classifier at different threshold values. An ROC, which can be considered as a gold standard to prove the competence of a classifier, is obtained to ascertain the sensitivity and specificity of our classifier. We observe that at threshold 0.4 we achieve true positive value of 1.0 (100%) sacrificing only 0.16 (16%) false positive value for the set of 50 T1 MRI analyzed in this experiment.

  19. A novel approach to remote homology detection: jumping alignments

    OpenAIRE

    Spang, Rainer; Rehmsmeier, Marc; Stoye, Jens

    2002-01-01

    We describe a new algorithm for protein classification and the detection of remote homologs. The rationale is to exploit both vertical and horizontal information of a multiple alignment in a well-balanced manner. This is in contrast to established methods such as profiles and profile hidden Markov models which focus on vertical information as they model the columns of the alignment independently and to family pairwise search which focuses on horizontal information as it treats given sequences...

  20. Detector for the remote detection of fluorescent substances

    OpenAIRE

    Vassal'lo Sanz, Juan; Vassal'lo Saco, Jara; Gutiérrez Ríos, Julio; Soto Macía, Iván; Gallego García, Elena; Maraver Abad, Patricia; Esteban Orobio, Angel; Madrano Gil, Alejandro

    2009-01-01

    The invention relates to a system and method for the detection of fluorescent substances, which can be used to locate fluorescent substances situated at an intermediate distance, including at least: laser emitting means emitting in a suitable band in order to produce fluorescences from the family of substances to be located; remote optical receiving means; means for analysing the fluorescence spectral band of the substances to be located; and control means for controlling the laser emitting m...

  1. Comparison of AMI-25 enhanced MRI and helical dynamic CT in the detection of hepatic lesions

    International Nuclear Information System (INIS)

    We performed AMI-25 enhanced MRI and helical dynamic CT in 12 cases of hepatic lesions. Nine of these were hepatocellular carcinomas. Two cases were metastatic liver tumors (the primary lesion was gastric in one and the other was gallbladder cancer). One case was suspected to be adenomatous hyperplasia. Thirty-two lesions were detected in T2-weighted SE images before AMI-25 administration, while 46 lesions were detected in AMI-25 enhanced MRI images. In particular, AMI-25 enhanced MRI was superior to plain MRI in lesions less than 10 mm in size. A total of 48 lesions were detected in helical dynamic CT. Although AMI-25 enhanced MRI almost equaled helical dynamic CT in the detection of liver tumors, helical dynamic CT was slightly superior to AMI-25 enhanced MRI in the detection of subphrenic lesions. It was possible to know the hemodynamics in each hepatic lesion by helical dynamic CT. AMI-25 enhanced MRI was useful to know the inclusion of reticuloendothelial system, and that yielded different diagnoses in adenomatous hyperplasia and well differentiated hepatocellular carcinoma. Helical dynamic CT was useful for qualitative diagnosis. Both AMI-25 enhanced MRI and helical dynamic CT contributed to the detection of liver tumor and qualitative diagnosis. (author)

  2. Application of millimeter-wave radiometry for remote chemical detection

    International Nuclear Information System (INIS)

    Passive millimeter-wave systems have been used in the past to remotely map solid targets and to measure low-pressure spectral lines of stratospheric and interstellar gases; however, its application to pressure-broadened spectral line detection of industrial emissions is new. We developed a radiative transfer model to determine feasibility and system requirements for passive millimeter-wave spectral detection of terrestrial gases. We designed and built a Dicke-switched multispectral radiometer in the 146-154-GHz band to detect nitric oxide (NO), a prototypical gas of nuclear fuel processing operations. We first tested the spectral detection capability of the radiometer in the laboratory using a gas cell and then field tested it at the Nevada test site at a distance of 600 m from a stack that released hot plumes of NO and air. With features such as Dicke-switched integration, frequent online calibration, and spectral baseline subtraction, we demonstrated the feasibility of remote detection of terrestrial gases by a ground-based radiometer

  3. Application of millimeter-wave radiometry for remote chemical detection.

    Energy Technology Data Exchange (ETDEWEB)

    Gopalsami, N.; Bakhtiari, S.; Elmer, T. W.; Raptis, A. C.; Nuclear Engineering Division

    2008-03-01

    Passive millimeter-wave systems have been used in the past to remotely map solid targets and to measure low-pressure spectral lines of stratospheric and interstellar gases; however, its application to pressure-broadened spectral line detection of industrial emissions is new. We developed a radiative transfer model to determine feasibility and system requirements for passive millimeter-wave spectral detection of terrestrial gases. We designed and built a Dicke-switched multispectral radiometer in the 146-154-GHz band to detect nitric oxide (NO), a prototypical gas of nuclear fuel processing operations. We first tested the spectral detection capability of the radiometer in the laboratory using a gas cell and then field tested it at the Nevada test site at a distance of 600 m from a stack that released hot plumes of NO and air. With features such as Dicke-switched integration, frequent online calibration, and spectral baseline subtraction, we demonstrated the feasibility of remote detection of terrestrial gases by a ground-based radiometer.

  4. Remote stress detection using a visible spectrum camera

    Science.gov (United States)

    Kaur, Balvinder; Moses, Sophia; Luthra, Megha; Ikonomidou, Vasiliki N.

    2015-05-01

    Heart rate variability (HRV) can be an important indicator of several conditions that affect the autonomic nervous system, including traumatic brain injury, post-traumatic stress disorder and peripheral neuropathy. Recent work has shown that some of the HRV features can potentially be used for distinguishing a subject's normal mental state from a stressed one. In all of these past works, HRV analysis is performed on the cardiac activity data acquired by conventional electrocardiography electrodes, which may introduce additional stress and complexity to the acquired data. In this paper we use remotely acquired time-series data extracted from the human facial skin reflectivity signal during rest and mental stress conditions to compute HRV driven features. We further apply a set of classification algorithms to distinguishing between these two states. To determine heart beat signal from the facial skin reflectivity, we apply Principal Component Analysis (PCA) for denoising and Independent Component Analysis (ICA) for source selection. To determine the signal peaks to extract the RR-interval time-series, we apply a threshold-based detection technique and additional peak conditioning algorithms. To classify RR-intervals, we explored classification algorithms that are commonly used for medical applications such as logistic regression and linear discriminant analysis (LDA). Goodness of each classifier is measured in terms of sensitivity/specificity. Results from each classifier are then compared to find the optimal classifier for stress detection. This work, performed under an IRB approved protocol, provides initial proof that remotely-acquired heart rate signal can be used for stress detection. This result shows promise for further development of a remote-sensing stress detection technique both for medical and deception-detection applications.

  5. Prenatal detection of microtia by MRI in a fetus with trisomy 22

    International Nuclear Information System (INIS)

    Trisomy 22 is a rare chromosomal abnormality infrequently detected prenatally. External ear abnormalities, in particular microtia, are often associated with trisomy 22, but prenatal detection of microtia has not been reported in association with trisomy 22. We report a fetus with trisomy 22, with fetal MRI findings of microtia, craniofacial dysmorphism, and polygyria. Fetal MRI is a useful tool for auricular assessment and might have utility in the prenatal detection of chromosomal abnormalities, especially among fetuses with structural anomalies. (orig.)

  6. Prenatal detection of microtia by MRI in a fetus with trisomy 22

    Energy Technology Data Exchange (ETDEWEB)

    Milic, Andrea; Blaser, Susan; Robinson, Ashley [University of Toronto, Department of Diagnostic Imaging, Hospital for Sick Children, Toronto (Canada); Viero, Sandra; Halliday, William [University of Toronto, Laboratory Medicine and Pathobiology, Hospital for Sick Children, Toronto (Canada); Winsor, Elizabeth [University of Toronto, Department of Laboratory Medicine and Pathobiology, Mount Sinai Hospital, Toronto (Canada); Toi, Ants [University of Toronto, Department of Diagnostic Imaging, Mount Sinai Hospital, Toronto (Canada); Thomas, Micki [University of Toronto, The Prenatal Diagnosis and Medical Genetics Program, Department of Obstetrics and Gynecology, Mount Sinai Hospital, Rm. 3292 Toronto, ON (Canada); Chitayat, David [University of Toronto, The Prenatal Diagnosis and Medical Genetics Program, Department of Obstetrics and Gynecology, Mount Sinai Hospital, Rm. 3292 Toronto, ON (Canada); University of Toronto, Clinical and Metabolic Genetics, Hospital for Sick Children, Toronto (Canada)

    2006-07-15

    Trisomy 22 is a rare chromosomal abnormality infrequently detected prenatally. External ear abnormalities, in particular microtia, are often associated with trisomy 22, but prenatal detection of microtia has not been reported in association with trisomy 22. We report a fetus with trisomy 22, with fetal MRI findings of microtia, craniofacial dysmorphism, and polygyria. Fetal MRI is a useful tool for auricular assessment and might have utility in the prenatal detection of chromosomal abnormalities, especially among fetuses with structural anomalies. (orig.)

  7. Remote measurement of microwave distribution based on optical detection

    Science.gov (United States)

    Ji, Zhong; Ding, Wenzheng; Yang, Sihua; Chen, Qun; Xing, Da

    2016-01-01

    In this letter, we present the development of a remote microwave measurement system. This method employs an arc discharge lamp that serves as an energy converter from microwave to visible light, which can propagate without transmission medium. Observed with a charge coupled device, quantitative microwave power distribution can be achieved when the operators and electronic instruments are in a distance from the high power region in order to reduce the potential risk. We perform the experiments using pulsed microwaves, and the results show that the system response is dependent on the microwave intensity over a certain range. Most importantly, the microwave distribution can be monitored in real time by optical observation of the response of a one-dimensional lamp array. The characteristics of low cost, a wide detection bandwidth, remote measurement, and room temperature operation make the system a preferred detector for microwave applications.

  8. Detection of rotator cuff tears: the value of MRI following ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    Rutten, Matthieu J.C.M.; Spaargaren, Gert-Jan; Jager, Gerrit J. [Jeroen Bosch Ziekenhuis, Department of Radiology, NL' s-Hertogenbosch (Netherlands); Loon, Ton van [Jeroen Bosch Ziekenhuis, Department of Orthopedic Surgery, NL' s-Hertogenbosch (Netherlands); Waal Malefijt, Maarten C. de [Radboud University Nijmegen Medical Centre, Department of Orthopedic Surgery, Nijmegen (Netherlands); Kiemeney, Lambertus A.L.M. [Radboud University Nijmegen Medical Centre, Department of Epidemiology and Biostatistics and HTA, Geert Grooteplein Noord 21, P.O. Box 9101, Nijmegen (Netherlands)

    2010-02-15

    To evaluate the need for additional magnetic resonance imaging (MRI) following ultrasound (US) in patients with shoulder pain and/or disability and to compare the accuracy of both techniques for the detection of partial-thickness and full-thickness rotator cuff tears (RCT). In 4 years, 5,216 patients underwent US by experienced musculoskeletal radiologists. Retrospectively, patient records were evaluated if MRI and surgery were performed within 5 months of US. US and MRI findings were classified into intact cuff, partial-thickness and full-thickness RCT, and were correlated with surgical findings. Additional MR imaging was performed in 275 (5.2%) patients. Sixty-eight patients underwent surgery within 5 months. US and MRI correctly depicted 21 (95%) and 22 (100%) of the 22 full-thickness tears, and 8 (89%) and 6 (67%) of the 9 partial-thickness tears, respectively. The differences in performance of US and MRI were not statistically significant (p = 0.15). MRI following routine shoulder US was requested in only 5.2% of the patients. The additional value of MRI was in detecting intra-articular lesions. In patients who underwent surgery, US and MRI yielded comparably high sensitivity for detecting full-thickness RCT. US performed better in detecting partial-thickness tears, although the difference was not significant. (orig.)

  9. Detection of rotator cuff tears: the value of MRI following ultrasound

    International Nuclear Information System (INIS)

    To evaluate the need for additional magnetic resonance imaging (MRI) following ultrasound (US) in patients with shoulder pain and/or disability and to compare the accuracy of both techniques for the detection of partial-thickness and full-thickness rotator cuff tears (RCT). In 4 years, 5,216 patients underwent US by experienced musculoskeletal radiologists. Retrospectively, patient records were evaluated if MRI and surgery were performed within 5 months of US. US and MRI findings were classified into intact cuff, partial-thickness and full-thickness RCT, and were correlated with surgical findings. Additional MR imaging was performed in 275 (5.2%) patients. Sixty-eight patients underwent surgery within 5 months. US and MRI correctly depicted 21 (95%) and 22 (100%) of the 22 full-thickness tears, and 8 (89%) and 6 (67%) of the 9 partial-thickness tears, respectively. The differences in performance of US and MRI were not statistically significant (p = 0.15). MRI following routine shoulder US was requested in only 5.2% of the patients. The additional value of MRI was in detecting intra-articular lesions. In patients who underwent surgery, US and MRI yielded comparably high sensitivity for detecting full-thickness RCT. US performed better in detecting partial-thickness tears, although the difference was not significant. (orig.)

  10. SQUID-detected NMR and MRI in microtesla magnetic fields

    Science.gov (United States)

    McDermott, Robert Francis

    A low transition temperature do Superconducting QUantum Interference Device (low-Tc do SQUID) was used to perform liquid-state nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) experiments in magnetic fields from microtesla to tens of microtesla, corresponding to proton Larmor frequencies from tens of Hz to kHz. The spins were polarized in a magnetic field of the order of millitesla. Upon turnoff of the polarizing field, precession was induced in the much weaker measurement field. Because the SQUID magnetometer was operated with an untuned, superconducting, input circuit, the integrated intensity of the NMR lines was independent of the strength of the measurement field. On the other hand, the NMR linewidth scaled linearly with the measurement field strength. Narrowing of the NMR signal bandwidth through reduction of the strength of the measurement field led to an enhancement of both spectral resolution and signal-to-noise ratio (SNR). A novel cryogenic insert was constructed to allow SQUID measurement of NMR signals from room temperature samples with high filling factor. From samples with volume of a few milliliters and thermal polarization of order 10 -8, SNR of a few tens were achieved in a single shot. Heteronuclear scalar couplings were resolved in 1H-31P and 1H-13C systems. Furthermore, the frequency-independent sensitivity of the untuned SQUID magnetometer allowed simultaneous detection of NMR signals from nuclei with different magnetogyric ratios. A system based on a low-Tc SQUID gradiometer was used to acquire MRIs from distilled water and mineral oil phantoms in microtesla fields. The bandwidth-narrowing technique was exploited to enhance spatial resolution for a fixed strength of the encoding gradients. With magnetic field gradients of the order of tens of microtesla per meter, images with spatial resolution of a millimeter were achieved. The techniques described in this thesis could readily be adapted for use with multichannel SQUID systems designed for biomagnetic measurements at low frequency, and represent a first step toward the development of low cost, portable NMR and MRI scanners based on untuned SQUID magnetometers.

  11. Underwater remote detection and monitoring of spilled Orimulsion using sonar

    International Nuclear Information System (INIS)

    An accidental spill of Orimulsion on water presents special challenges because the Orimulsion will go into suspension as microscopic surfactant coated bitumen particles in the first 2-3 metres below the water surface. This makes it difficult to detect and monitor the plume. Fleming Co. Environmental examined the potential use of sonar for the underwater remote detection and monitoring of spilled Orimulsion in a small-scale saltwater tank test in Denmark. For the test, a sonar was placed 0.75 m below the water surface at one end of the tank. Acoustic measurements showed that a gradually spreading cloud containing only 5.6 liters of hydrocarbon particles could be detected from 17 meters away in a body of 180,000 liters, even when the sonar was functioning at only 6 per cent of its full power. These positive results may lead to further tank testing or offshore testing in Venezuela. 4 refs., 9 figs

  12. Whole-body muscle MRI to detect myopathies in non-extrapyramidal bent spine syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Ohana, Mickael [Nouvel Hopital Civil - Hopitaux Universitaires de Strasbourg, Service de Radiologie B, Strasbourg (France); Durand, Marie-Christine [AP-HP - Hopital Raymond Poincare, Service de Neurologie, Garches (France); Marty, Catherine; Lazareth, Jean-Philippe [AP-HP - Hopital Raymond Poincare, Service de Rhumatologie, Garches (France); Maisonobe, Thierry [APH-HP - Hopital de la Pitie-Salpetriere, Service de Neuropathologie, Paris (France); Mompoint, Dominique; Carlier, Robert-Yves [AP-HP - Hopital Raymond Poincare, Service de Radiologie, Garches (France)

    2014-08-15

    Bent spine syndrome (BSS), defined as an abnormal forward flexion of the trunk resolving in supine position, is usually related to parkinsonism, but can also be encountered in myopathies. This study evaluates whole-body muscle MRI (WB-mMRI) as a tool for detecting underlying myopathy in non-extrapyramidal BSS. Forty-three patients (90 % women; 53-86 years old) with a non-extrapyramidal BSS were prospectively included. All underwent a 1.5-T WB-mMRI and a nerve conduction study. Muscle biopsy was performed if a myopathy could not be eliminated based on clinical examination and all tests. Systematic MRI interpretation focused on peripheral and axial muscle injury; spinal posture and incidental findings were also reported. WB-mMRI was completed for all patients, with 13 muscle biopsies ultimately needed and myopathy revealed as the final etiological diagnosis in five cases (12 %). All biopsy-proven myopathies were detected by the WB-mMRI. Relevant incidental MRI findings were made in seven patients. This study supports WB-mMRI as a sensitive and feasible tool for detecting myopathy in BSS patients. Associated with electroneuromyography, it can better indicate when a muscle biopsy is needed and guide it when required. Rigorous radiological interpretation is mandatory, so as not to miss incidental findings of clinical consequence. (orig.)

  13. Comparison of Ultrasound and MRI in Detecting Fetal Anomalies

    Directory of Open Access Journals (Sweden)

    R. Abdi

    2005-08-01

    Full Text Available Introduction & Background: Ultrasound (US and MRI are considered complementary technologies, and MRI is utilized as an adjunct to US in the evaluation of fetal anomalies. Overall ultrasound remains the prime mo-dality for evaluating disorders of the fetus and pregnancy. Ultrasound continues to have several obvious advan-tages over MRI. It is safe and relatively inexpensive and is widely available It also allows for real-time imaging. However, US does have important limitations. First, it is uniquely operator-and interpreter-dependent. In ad-dition, compared to MRI, US provides a smaller field-of-view, and the resolution of US images is restricted by penetration through soft tissues and bone. Thus, the sensitivity of US in evaluating the fetus is reduced in obese patients and in women whose pregnancies are complicated by low amniotic fluid volume. There is a growing body of literature on the use of MRI and has documented its usefulness in confirming or expanding upon US findings. On the contrary, MRI visualization of the fetus is not significantly limited by maternal obe-sity, fetal position, or oligohydramnios, and visualization of the brain is not restricted by the ossified skull. It provides superior soft-tissue contrast resolution and the ability to distinguish individual structures such as lung, liver, kidney, bowel, and gray and white matter. Patients & Methods: In this study, patients in the second and third trimesters of pregnancy were recruited on the basis of abnormal fetal US results within 2 days of MR imaging by another radiologist. Results: In some cases such as anencephaly which is associated with polyhydraminous or in multicystic dys-plastic kidney disease, MRI added no more information to ultrasonography; but in the following cases MRI had more data. In a fetus with bilateral hydronephrosis, MRI could differentiate PUV from UPJ stenosis by visualizing distention of the ureters. MRI allowed better depiction of complex anomalies which are associated with omphalocele, such as a small thorax and rudimentary cervical spine. MRI could differentiate cystic hy-groma from meningocele with showing no defect in the occipital bone. Conclusion: Although US remains the examination of choice for evaluating the fetus, obstetric MR imaging serves as a useful adjuvant study. With the development of faster MR imaging sequences, greater anatomic de-tail of the fetus is visualized. Thus, a clear understanding of MR imaging techniques and fetal anatomy is cru-cial for optimal examination and image interpretation.

  14. Functional MRI detection of pharmacologically induced memory impairment

    OpenAIRE

    Sperling, Reisa; Greve, Douglas; Dale, Anders; Killiany, Ronald; Holmes, Jennifer; Rosas, H Diana; Cocchiarella, Andrew; Firth, Paul; Rosen, Bruce; Lake, Stephen; Lange, Nicholas; Routledge, Carol; Albert, Marilyn

    2001-01-01

    To examine alterations in brain activation associated with pharmacologically induced memory impairment, we used functional MRI (fMRI) to study the effects of lorazepam and scopolamine on a face–name associative encoding paradigm. Ten healthy young subjects were scanned on four occasions, 2 weeks apart; they were administered i.v. saline during two placebo-scanning sessions and then alternately administered i.v. lorazepam (1 mg) or scopolamine (0.4 mg) in a double-b...

  15. Diffusion-weighted MRI for detecting prostate tumour in men at increased genetic risk

    Directory of Open Access Journals (Sweden)

    Nandita M. deSouza

    2014-01-01

    Conclusion: Endorectal T2W + DW-MRI at 3.0 T yields high sensitivity and specificity for tumour detection by an experienced observer in screening men with a family history of prostate cancer and increased genetic risk.

  16. NMR analysis on microfluidic devices by remote detection

    Energy Technology Data Exchange (ETDEWEB)

    McDonnell, Erin E.; Han, SongI; Hilty, Christian; Pierce,Kimberly; Pines, Alexander

    2005-08-15

    We present a novel approach to perform high-sensitivity NMR imaging and spectroscopic analysis on microfluidic devices. The application of NMR, the most information rich spectroscopic technique, to microfluidic devices remains a challenge because the inherently low sensitivity of NMR is aggravated by small fluid volumes leading to low NMR signal, and geometric constraints resulting in poor efficiency for inductive detection. We address the latter by physically separating signal detection from encoding of information with remote detection. Thereby, we use a commercial imaging probe with sufficiently large diameter to encompass the entire device, enabling encoding of NMR information at any location on the chip. Because large-diameter coils are too insensitive for detection, we store the encoded information as longitudinal magnetization and flow it into the outlet capillary. There, we detect the signal with optimal sensitivity using a solenoidal microcoil, and reconstruct the information encoded in the fluid. We present a generally applicable design for a detection-only microcoil probe that can be inserted into the bore of a commercial imaging probe. Using hyperpolarized 129Xe gas, we show that this probe enables sensitive reconstruction of NMR spectroscopic information encoded by the large imaging probe while keeping the flexibility of a large coil.

  17. Detection of intraplaque hemorrhage with use of screening black-blood MRI

    International Nuclear Information System (INIS)

    The evaluation of plaque characteristics as well as the degree of luminal narrowing is important in the management of carotid stenosis. Several reports have shown that intraplaque hemorrhage (IPH), which plays a pivotal role in plaque vulnerability, emits high signal intensity on T1-weighted images of high-resolution black-blood (BB) MRIs. When an MRI is used to screen for vulnerable plaque, a short scanning duration and a simple MRI protocol are required. This study assessed the utility of screening BB-MRI to detect IPH. Ninety-three consecutive cases with atherosclerotic carotid stenosis scheduled for carotid endarterectomy (CEA) or carotid artery stenting between January 2005 and December 2007 were included. High-resolution BB-MRI scans were obtained with 2D double-inversion recovery fast spin-echo sequences with cardiac gating. Screening BB-MRIs were performed with 3D gradient-echo sequences suppressing blood flow signals by radiofrequency wave spatial saturation over the scanning field of 3D time-of-flight MR angiography (MRA). The relative overall plaque signal intensities with reference to the sternocleidomastoid muscle were calculated, and the correlation of intensities on T1-weighted images between high-resolution BB-MRI and screening BB-MRI was investigated. We excluded 50 cases because of restenosis following CEA, use of a pacemaker, a long interval (>10 days) between high-resolution and screening BB-MRI examinations, or poor-quality images. Among the 43 cases included, the relative overall plaque signal intensity of high-resolution BB-MRI and screening BB-MRI were closely correlated (r=0.568, p<0.001). Screening BB-MRI can be an alternative to high-resolution BB-MRI in the assessment of IPH and may be a useful tool for detection of vulnerable plaque. (author)

  18. Preoperative detection of colorectal liver metastases in fatty liver: MDCT or MRI?

    International Nuclear Information System (INIS)

    Objective: To compare the diagnostic value of multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) in the preoperative detection of colorectal liver metastases in diffuse fatty infiltration of the liver, associated with neoadjuvant chemotherapy. Materials and methods: Twenty preoperative tri-phasic MDCT (4-64-row, Siemens) and dynamic contrast-enhanced MRI (1.5 T or 3.0 T, Siemens) examinations of patients with colorectal cancer and liver metastases in diffuse steatosis were retrospectively evaluated. All patients underwent surgical resection for liver metastases (time interval 1-60 days). The amount of fatty infiltration of the liver was determined histopathologically by semi-quantitative percent-wise estimation and ranged from 25 to 75%. Results: Overall, 51 metastases were found by histopathology of the resected liver segments/lobes. The size of the metastases ranged from 0.4 to 13 cm, with 18 (35%) being up to 1 cm in diameter. In the overall rating, MDCT detected 33/51 lesions (65%), and MRI 45/51 (88%). For lesions up to 1 cm, MDCT detected only 2/18 (11%) and MRI 12/18 (66%). One false positive lesion was detected by MDCT. Statistical analysis showed that MRI is markedly superior to MDCT, with a statistically significant difference (p 1 cm. Conclusion: For the detection of colorectal liver metastases after neoadjuvant chemotherapy and consecutive diffuse fatty infiltration of the liver, MRI is superior to MDCT, especially for the detection of small lesions.

  19. Advanced device for remote detection of alpha-radioactive sources

    International Nuclear Information System (INIS)

    We developed a portable device for remote control of alpha-active nuclide contamination in the presence of beta and gamma radiation in actual atmospheric conditions in the real time mode. Alpha-particle detection is effected through registration of air ions generated on particle tracks. The air ions are transferred from the particle tracks into the detector operative chamber by air flux. The registration is performed by gas discharges using a wire counter open towards the air flux. The device will provide air flux running over the investigated surface of any complicated profile and continuous transport of air ions to the work chamber of the detector. The device can be used as indoor atmosphere monitor. It allows continuous blowing through working volume and detects appearance the radioactive aerosol. The device can also be used to conduct automated monitoring of drinking water

  20. A remote fiber optic dosimeter network for detecting hydrazine vapor

    International Nuclear Information System (INIS)

    A fiber optic chemical dosimeter has been developed for use in the remote detection of vapors of toxic amine rocket fuels (hydrazine and its substituted derivatives) that are used as Air Force and civilian launch sites. The dosimeter employs a colorimetric indicating reagent immobilized in a porous sol-gel cladding on multimode fiber. This reagent reacts selectively with the fuel vapor to produce a strongly absorbing cladding that introduces light propagation losses in the fiber; these losses indicate the presence of hydrazine (N2H4) vapor. The absorption occurs over a broad spectral range ideally suited for interrogation by semiconductor diode lasers. The authors have shown that the dosimeter yields an average hydrazine detectivity of 2.3 exposures of the dosimeter to laboratory air have not adversely affected the dosimeter. Additionally, its response to ammonia vapor has been determined to be 9,200 times smaller than its response to hydrazine vapor

  1. Sensitive change detection for remote sensing monitoring of nuclear treaties

    DEFF Research Database (Denmark)

    Canty, Morton J.; Nielsen, Allan Aasbjerg

    2005-01-01

    Triggered in part by the advent of high resolution commercial optical satellites, the analysis of open-source satellite imagery has now established itself as an important tool for monitoring nuclear activities throughout the world (Chitumbo et al 2001). Whereas detection of land cover and land use change is a commonplace application in remote sensing, the detection of anthropogenic changes associated with nuclear activities, whether declared or clandestine, presents a difficult challenge. It is necessary to discriminate subtle, often weak signals of interest on a background of irrelevant or uninteresting changes, see e.g. (Canty and Schlittenhardt 2001). In our contribution we focus attention on the use of conventional multispectral earth observation satellite platforms with moderate ground resolution (Landsat TM, ASTER, SPOT) to detect changes over wide areas which are relevant to nuclear non-proliferation and disarmament treaties. The analysis is based upon the multivariate alteration detection (MAD) algorithm proposed by Nielsen et al. 1998 with the inclusion of a recent refinement which puts weight on difficult observations (Nielsen to be published). The multispectral data are pre-processed by orthorectification, illumination angle correction, image registration to sub-pixel accuracy and, where appropriate, wavelet-based panchromatic sharpening. We illustrate the techniques with a number of case studies involving the location of underground nuclear explosions and detection of uranium mining sites. In the former case the change signals are compared with existing seismic data, which include explosion times, locations, yields and depths of burial as well as data about surface collapse (subsidence) phenomena like e.g. crater depth and diameter and test surface-collapse times. The work has been carried out within the framework of the Global Monitoring for Security and Stability Network of Excellence (GMOSS) initiated by the European Commission. Chitumbo, K., Robb, S., Bunney, J. and Lev\\$\\backslash\\$'e, G., IAEA Satellite imagery and the Department of Safeguards, Proceedings of the Symposium on International Safeguards, Vienna 2001 IAEA-SM-367/16/08) on CD-ROM. Canty, M. J., Schlittenhardt, J., Locating the 1998 Indian nuclear tests, Eos, Transactions American Geophysical Union 82(3), 2001, pp. 25--29. Nielsen, A. A., Conradsen, K. and Simpson, J. J., Multivariate alteration detection (MAD) and MAF processing in multispectral, bitemporal image data: New approaches to change detection studies, Remote Sens. Environ. 64(1), 1998, pp. 1--19. Nielsen, A. A., Iteratively re-weighted multivariate alteration detection in multi- and hyperspectral data, to be published.

  2. Detection of Myocardial Infarct Region Using PET and MRI Images

    Energy Technology Data Exchange (ETDEWEB)

    Woo, Sang Keun; Lee, Yong Jin; Lee, Won Ho [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2010-10-15

    Development of novel myocardial imaging techniques and preclinical testing of cardiovascular radiopharmaceuticals require an in vivo heart model of small animals such as rats. Cardiac disease research relies increasingly on small animal models and non-invasive imaging methods such as PET/CT and MRI. PET is the most reliable non-invasive tool for the identification of myocardial viability and myocardial perfusion. MRI provides high resolution anatomical images that allow accurate evaluation of ventricular structure. However, a direct comparison among multimodal image for characterization of perfusion, viability, and infarct size is lacking. The aim of this study was to improve quantitative assessment of rat myocardial infarct (MI) size using attenuation corrected PET polar map with gated CT image and MRI polarmap

  3. The comparative study of ferucarbotran enhanced MRI in detecting focal hepatic lesions

    International Nuclear Information System (INIS)

    Objective: To evaluate the efficacy of ferucarbotran enhanced MRI in the detection of focal hepatic lesions by means of comparison with plain and Gd-DTPA enhanced MRI. Methods: Between December 2003 and July 2004, 59 consecutive patients with suspected focal hepatic lesions were undergone in study. Plain MRI (such as FSE T2WI with fat suppression and GRE T1WI sequences) and Gd-DTPA dynamic enhanced MRI of the liver were initially performed, then followed by ferucarbotran enhanced MRI (including GRE T1WI, FSE T2WI with fat suppression and GRE T2*WI sequences) 48 hours later. The sensitivity were statistically calculated by different sequences of MRI. Results: There were 130 lesions on FSE T2WI with fat suppression, 115 lesions on dynamic T1WI GRE and 127 lesions on GRE T2*WI respectively which were studied by ferucarbotran enhanced MRI. There were only 84 lesions on GRE T1WI and 106 lesions on FSE T2WI with fat suppression which were detected by pre-contrast MRI, meanwhile one hundred twenty-three lesions were found by Gd-DTPA dynamic enhanced GRE T1WI. Among 44 micro- lesions(2WI with fat suppression, 88.6% (39/44) for ferucarbotran enhanced GRE T2*WI, 79.5% (35/44) for Gd-DTPA dynamic enhanced GRE T1WI, 54.5% (24/44) for pre-contrast FSE T2WI with fat suppression and 34.1% (15/44) for pre-contrast GRE T1WI. Ferucarbotran-enhanced FSE T2WI with fat suppression and GRE T2*WI sequences had statistically significant difference with the other sequences in detecting micro-lesions (P2WI with fat suppression and GRE T2*WI sequences markedly improved the detection of the micro-lesions (< 1 cm) in comparison with plain and Gd-DTPA dynamic enhanced MRI. (authors)

  4. Prostate Cancer Detection: The Value of Performing an MRI before a Biopsy

    International Nuclear Information System (INIS)

    Background: In recent years, prostate-specific antigen (PSA) screening has been widely performed. As a result, patients who need to undergo a complete physical examination for an elevated PSA level have been rapidly increasing. Magnetic resonance imaging (MRI) examination has previously been reported to be effective for the detection of prostate cancer. Purpose: To evaluate the detectability of prostate cancer by performing MRI before biopsy, and to evaluate the relationship between detectability with MRI and cancer location, Gleason score (GS), and tumor size. Material and Methods: MRI was performed at 1.5 Tesla in 122 consecutive patients before biopsy. The detectability of prostate cancer, including sensitivity and positive predictive value (PPV) of transrectal ultrasonography (TRUS), T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI) (b=2000 s/mm2), apparent diffusion coefficient (ADC) map, and biopsy, was calculated using whole-mount section histopathology as a gold standard. In addition, the relationship between the detectability on each MRI sequence and factors such as cancer location (peripheral zone vs. transition zone), GS 5-10, short-axis diameter (=4 mm, 5-9 mm, =10 mm), and long-axis diameter (=9 mm, 10-19 mm, =20 mm) were also evaluated. Results: The sensitivities of TRUS, T2WI, DWI, ADC map, and biopsy were 26.9%, 41.2%, 56.7%, 57.7%, and 75.1%, respectively, and the PPVs of those modalities were 73.0%, 83.0%, 86.4%, 87.2%, and 91.5%, respectively. There was no correlation between the sensitivity of each MRI sequence and cancer location. The sensitivity of each MRI sequence increased as GS and short- and long-axis diameters of cancer lesions increased. Conclusion: MRI before a biopsy has a high detectability of prostate cancer, particularly with tumor size of more than 5 mm in short-axis diameter or 10 mm in long-axis diameter

  5. Early detection of Alzheimer's disease using MRI hippocampal texture

    DEFF Research Database (Denmark)

    Sørensen, Lauge Emil Borch Laurs; Igel, Christian; Hansen, Naja Liv; Osler, Merete; Lauritzen, Martin; Rostrup, Egill; Nielsen, Mads

    2016-01-01

    Cognitive impairment in patients with Alzheimer's disease (AD) is associated with reduction in hippocampal volume in magnetic resonance imaging (MRI). However, it is unknown whether hippocampal texture changes in persons with mild cognitive impairment (MCI) that does not have a change in...... hippocampal volume. We tested the hypothesis that hippocampal texture has association to early cognitive loss beyond that of volumetric changes. The texture marker was trained and evaluated using T1-weighted MRI scans from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database, and subsequently...

  6. Building multiclass classifiers for remote homology detection and fold recognition

    Directory of Open Access Journals (Sweden)

    Karypis George

    2006-10-01

    Full Text Available Abstract Background Protein remote homology detection and fold recognition are central problems in computational biology. Supervised learning algorithms based on support vector machines are currently one of the most effective methods for solving these problems. These methods are primarily used to solve binary classification problems and they have not been extensively used to solve the more general multiclass remote homology prediction and fold recognition problems. Results We present a comprehensive evaluation of a number of methods for building SVM-based multiclass classification schemes in the context of the SCOP protein classification. These methods include schemes that directly build an SVM-based multiclass model, schemes that employ a second-level learning approach to combine the predictions generated by a set of binary SVM-based classifiers, and schemes that build and combine binary classifiers for various levels of the SCOP hierarchy beyond those defining the target classes. Conclusion Analyzing the performance achieved by the different approaches on four different datasets we show that most of the proposed multiclass SVM-based classification approaches are quite effective in solving the remote homology prediction and fold recognition problems and that the schemes that use predictions from binary models constructed for ancestral categories within the SCOP hierarchy tend to not only lead to lower error rates but also reduce the number of errors in which a superfamily is assigned to an entirely different fold and a fold is predicted as being from a different SCOP class. Our results also show that the limited size of the training data makes it hard to learn complex second-level models, and that models of moderate complexity lead to consistently better results.

  7. Fracture identification based on remote detection acoustic reflection logging

    Science.gov (United States)

    Zhang, Gong; Li, Ning; Guo, Hong-Wei; Wu, Hong-Liang; Luo, Chao

    2015-12-01

    Fracture identification is important for the evaluation of carbonate reservoirs. However, conventional logging equipment has small depth of investigation and cannot detect rock fractures more than three meters away from the borehole. Remote acoustic logging uses phase-controlled array-transmitting and long sound probes that increase the depth of investigation. The interpretation of logging data with respect to fractures is typically guided by practical experience rather than theory and is often ambiguous. We use remote acoustic reflection logging data and high-order finite-difference approximations in the forward modeling and prestack reverse-time migration to image fractures. First, we perform forward modeling of the fracture responses as a function of the fracture-borehole wall distance, aperture, and dip angle. Second, we extract the energy intensity within the imaging area to determine whether the fracture can be identified as the formation velocity is varied. Finally, we evaluate the effect of the fracture-borehole distance, fracture aperture, and dip angle on fracture identification.

  8. Mineralogy and astrobiology detection using laser remote sensing instrument.

    Science.gov (United States)

    Abedin, M Nurul; Bradley, Arthur T; Sharma, Shiv K; Misra, Anupam K; Lucey, Paul G; McKay, Christopher P; Ismail, Syed; Sandford, Stephen P

    2015-09-01

    A multispectral instrument based on Raman, laser-induced fluorescence (LIF), laser-induced breakdown spectroscopy (LIBS), and a lidar system provides high-fidelity scientific investigations, scientific input, and science operation constraints in the context of planetary field campaigns with the Jupiter Europa Robotic Lander and Mars Sample Return mission opportunities. This instrument conducts scientific investigations analogous to investigations anticipated for missions to Mars and Jupiter's icy moons. This combined multispectral instrument is capable of performing Raman and fluorescence spectroscopy out to a >100  m target distance from the rover system and provides single-wavelength atmospheric profiling over long ranges (>20  km). In this article, we will reveal integrated remote Raman, LIF, and lidar technologies for use in robotic and lander-based planetary remote sensing applications. Discussions are focused on recently developed Raman, LIF, and lidar systems in addition to emphasizing surface water ice, surface and subsurface minerals, organics, biogenic, biomarker identification, atmospheric aerosols and clouds distributions, i.e., near-field atmospheric thin layers detection for next robotic-lander based instruments to measure all the above-mentioned parameters. PMID:26368883

  9. Comparision the value of detecting myocardial viability between low dose dobutamine stress MRI and echocardiography

    International Nuclear Information System (INIS)

    Objective: To Compare the diagnostic value between low dose dobutamine stress transthrotic echocardiography and low dose dobutamine stress MRI in detecting myocardial viability of chronic myocardial infarction. Methods: Rest and low dose dobutamine (5, 10 ?g·kg-1·min-1) stress transthrotic echocardiography and cine-MRI were performed in 30 patients with chronic myocardial infarction. 24 patients underwent successful revascularization and 10 of them underwent another rest cine-MRI study to assess segmental myocardial functional recovery. Left ventricular were divided into 16 segments, the criteria of viability in different techniques is: MRI: dobutamine induced systolic wall thickening was ?2 mm in akinetic or diskinetic segments at rest; Echocardiography: wall motion score reduced at least 1 after dobutamine stress in akinetic or' diskinetic segments at rest. Results: One hundren and eight segments showed wall motion abnormalities of 30 patients, 65 and 56 segments shows positive reaction, 43 and 52 segments shows negativereaction in MRI and echocardiography after dobutamine stress respectively. Kappa value of the two techniques is 0.75, concordance in both techniques is 88%. Twenty-four segments showed functional recovery, 14 segments remained dysfunction 3-6 months after revascularization, the sensitivity, specificity and accuracy of detecting myocardial viability in chronic myocardial infarction in MRI and echocardiography is 95.8% vs 79.2% (P>0.05), 85.7% vs 85.7% (P>0.05), 92.1% vs 81.6% (P>0.05) respectively. The sensitivity and accuracy of MRI is a little higher. Conclusion: The ability of detecting myocardial viability by both low dose dobutamine stress transthrotic echocardiography and low dose dobutamine stress MRI is similer, the sensitivity and accuracy of MRI is a little higher. (authors)

  10. Detection of apical hypertrophic cardiomyopathy by cardiovascular MRI

    International Nuclear Information System (INIS)

    Objective: To investigate the clinical value of cardiovascular magnetic resonance imaging (cMRI) in identifying apical hypertrophic cardiomyopathy. Methods: Sixty-five patients with typical apical hypertrophic cardiomyopathy (T-AHCM), 51 patients with pre-apical hypertrophic cardiomyopathy (P-AHCM)and 26 normal controls were confirmed by cMRI. All cases underwent electrocardiogram and echocardiography, of which 16 and 34 cases were studied by radionuclide 99Tcm-MIBI SPECT myocardial scanning and coronary angiography plus left ventriculography, respectively. Results: cMRI confirmed all patients with apical hypertrophic cardiomyopathy, but echocardiography missed 96 cases. Two chamber and four chamber views of cine-cMRI were considered as the best position to show detailed structure of cardiac apex. Forty-seven cases showed spade-like configuration of left ventricular cavity in T-AHCM group, but only 15 patients in P-AHCM group presented the same character. T-AHCM group showed higher apical thickness and ratio of the apical wall thickness to that at basal level than P-AHCM group(18.6±2.7) mm vs (13.6±1.0) mm, 2.2±0.5 vs 1.6±0.3, P<0.05), and the ratios of both T-AHCM group and P-AHCM group were significantly higher than that of control group (9.5±1.7) mm, 1.1±0.1, P<0.05). Hypertrophic wall thickening was lesser in T-AHCM group than in P-AHCM group, while the values of both T-AHCM group and P-AHCM group were significantly lesser than that of control one. Conclusion: MRI is the best diagnostic modality for AHCM, which is highly accurate and better than echocardiography, especially for the diagnosis of mild hypertrophy in the early stage. (authors)

  11. Does low-field dedicated extremity MRI (E-MRI) reliably detect bone erosions in rheumatoid arthritis?

    DEFF Research Database (Denmark)

    Duer-Jensen, A; Ejbjerg, B; Albrecht-Beste, E; Vestergaard, A; Døhn, U Møller; Hetland, Merete Lund; Østergaard, Mikkel

    2009-01-01

    OBJECTIVES: To compare the ability of two different E-MRI units and conventional radiography (CR) to identify bone erosions in rheumatoid arthritis (RA) metacarpophalangeal (MCP) and wrist joints with CT scanning as the standard reference method. METHODS: 20 patients with RA and 5 controls...... underwent CR, CT and two E-MRI examinations (Esaote Biomedica Artoscan and MagneVu MV1000) of one hand during a 2-week period. In all modalities, each bone of the wrist and MCP joints was blindly evaluated for erosions. MagneVu images were also assessed for the proportion of each bone being visualised...... were visualised entirely and 37.9% of bones were 67-99% visualised. In MCP joints, 84.2% of bones were visualised entirely and 15.8% of bones were 67-99% visualised. CONCLUSION: With CT as the reference method for detecting erosions in RA hands, the Artoscan showed higher sensitivity than the Magne...

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

    OpenAIRE

    Clemens, Benjamin; Regenbogen, Christina; Koch, Kathrin; Backes, Volker; Romanczuk-Seiferth, Nina; Pauly, Katharina; Shah, N J; 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 be...

  13. Portable remote laser sensor for methane leak detection

    Science.gov (United States)

    Grant, W. B.; Hinkley, E. D., Jr. (inventor)

    1984-01-01

    A portable laser system for remote detection of methane gas leaks and concentrations is disclosed. The system transmitter includes first and second lasers, tuned respectively to a wavelength coincident with a strong absorption line of methane and a reference wavelength which is weakly absorbed by methane gas. The system receiver includes a spherical mirror for collecting the reflected laser radiation and focusing the collected radiation through a narrowband optical filter onto an optial detector. The filter is tuned to the wavelength of the two lasers, and rejects background noise. The output of the optical detector is processed by a lock-in detector synchronized to the chopper, and which measures the difference between the first wavelength signal and the reference wavelength signal.

  14. Ellipsoids for anomaly detection in remote sensing imagery

    Science.gov (United States)

    Grosklos, Guenchik; Theiler, James

    2015-05-01

    For many target and anomaly detection algorithms, a key step is the estimation of a centroid (relatively easy) and a covariance matrix (somewhat harder) that characterize the background clutter. For a background that can be modeled as a multivariate Gaussian, the centroid and covariance lead to an explicit probability density function that can be used in likelihood ratio tests for optimal detection statistics. But ellipsoidal contours can characterize a much larger class of multivariate density function, and the ellipsoids that characterize the outer periphery of the distribution are most appropriate for detection in the low false alarm rate regime. Traditionally the sample mean and sample covariance are used to estimate ellipsoid location and shape, but these quantities are confounded both by large lever-arm outliers and non-Gaussian distributions within the ellipsoid of interest. This paper compares a variety of centroid and covariance estimation schemes with the aim of characterizing the periphery of the background distribution. In particular, we will consider a robust variant of the Khachiyan algorithm for minimum-volume enclosing ellipsoid. The performance of these different approaches is evaluated on multispectral and hyperspectral remote sensing imagery using coverage plots of ellipsoid volume versus false alarm rate.

  15. Remote Detection of Iodine By using Differential Absorption Lidar

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Donglyul; Baik, Seunghoon; Park, Seungkyu; Park, Nakgyu; Ahn, Yongjin [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Differential absorption lidar (DIAL) is frequently used for atmospheric gas monitoring to detect impurities such as nitrogen dioxide, sulfur dioxide, iodine, and ozone. In this paper, DIAL technique of using remote sensing experiment is performed in the previous step. Radioactive iodine emitted by nuclear plants, however, is not frequently measured using DIAL because of the difficulty in preparing samples and its dangerous characteristics. In this paper, we configurated the DIAL system in our laboratory. A head detect the iodine gas of air and detect the iodine gas of cell in the distance of 90m. To lock the frequency of Nd:YAG laser, the iodine cell was used for discriminator. We acquired the signals from iodine cell by various frequency locking ratio that were from 0.1 to 0.9 by steps of 0.1. In the paper, we confirmed that the signals from the iodine target cell was proportional to the frequency locking ratio of the laser. For the iodine measurement, the transmission ratio using the injection-seeded laser is locked to 0.9 (off line) and 0.1 (on line) on the edges of the iodine absorption line to stabilize the frequency. The DIAL measurements were performed using a target iodine cell in the laboratory. We confirmed that the on- to off-line ratio decreased after the laser passed through the iodine cell.

  16. Remote Detection of Iodine By using Differential Absorption Lidar

    International Nuclear Information System (INIS)

    Differential absorption lidar (DIAL) is frequently used for atmospheric gas monitoring to detect impurities such as nitrogen dioxide, sulfur dioxide, iodine, and ozone. In this paper, DIAL technique of using remote sensing experiment is performed in the previous step. Radioactive iodine emitted by nuclear plants, however, is not frequently measured using DIAL because of the difficulty in preparing samples and its dangerous characteristics. In this paper, we configurated the DIAL system in our laboratory. A head detect the iodine gas of air and detect the iodine gas of cell in the distance of 90m. To lock the frequency of Nd:YAG laser, the iodine cell was used for discriminator. We acquired the signals from iodine cell by various frequency locking ratio that were from 0.1 to 0.9 by steps of 0.1. In the paper, we confirmed that the signals from the iodine target cell was proportional to the frequency locking ratio of the laser. For the iodine measurement, the transmission ratio using the injection-seeded laser is locked to 0.9 (off line) and 0.1 (on line) on the edges of the iodine absorption line to stabilize the frequency. The DIAL measurements were performed using a target iodine cell in the laboratory. We confirmed that the on- to off-line ratio decreased after the laser passed through the iodine cell

  17. A Review on Automated Brain Tumor Detection and Segmentation from MRI of Brain

    OpenAIRE

    Roy, Sudipta; Nag, Sanjay; Maitra, Indra Kanta; Samir Kumar BANDYOPADHYAY

    2013-01-01

    Tumor segmentation from magnetic resonance imaging (MRI) data is an important but time consuming manual task performed by medical experts. Automating this process is a challenging task because of the high diversity in the appearance of tumor tissues among different patients and in many cases similarity with the normal tissues. MRI is an advanced medical imaging technique providing rich information about the human soft-tissue anatomy. There are different brain tumor detection...

  18. MRI Brain Tumor Segmentation and Necrosis Detection Using Adaptive Sobolev Snakes

    OpenAIRE

    Nakhmani, Arie; Kikinis, Ron; Tannenbaum, Allen

    2014-01-01

    Brain tumor segmentation in brain MRI volumes is used in neurosurgical planning and illness staging. It is important to explore the tumor shape and necrosis regions at different points of time to evaluate the disease progression. We propose an algorithm for semi-automatic tumor segmentation and necrosis detection. Our algorithm consists of three parts: conversion of MRI volume to a probability space based on the on-line learned model, tumor probability density estimation, and adaptive segment...

  19. Time resolved optical detection for white matter lesion detection: preclinical tests on macaque brains and MRI co-registration

    Science.gov (United States)

    Planat-Chrétien, A.; Berger, M.; Hervé, L.; Watroba, L.; Demilly, J.; Flament, J.; Stimmer, L.; Aubourg, P.; Dinten, J.-M.

    2015-07-01

    We conducted a preclinical assessment on young macaques aimed at detecting white matter lesions. We present the protocol we implemented to achieve the lesions detection using a bedside non-invasive optical-based Time-Resolved instrumentation we have optimized for this purpose. We validated the reconstructed 3D absorption map with co-registration of MRI data.

  20. Vehicle Accident Automatic Detection and Remote Alarm Device

    Directory of Open Access Journals (Sweden)

    Varsha Goud

    2012-06-01

    Full Text Available The Rapid growth of  technology and infrastructure has made our lives more easy . The advent of technology has also increased the traffic hazards and the  road  accident take place frequently which causes huge loss of life and property because of the poor emergency facilities. Our project will provide an optimum solution to this draw back. An accelerometer can be used in a car alarm application so that dangerous driving can be detected . It can be used as a crash or rollover detector of the vehicle during and after a crash. With signals from an accelerometer, a severe accident can be recognized. According to this project when a vehicle meets with an accident immediately Vibration sensor will detect the signal or if a car rolls over, an Micro electro mechanical system(MEMS sensor will detects the signal and sends it to ARM controller. Microcontroller sends the alert message through the GSM MODEM including the location to police control room or a rescue team. So the police can immediately trace the location through the GPS MODEM, after receiving the information. Then after conforming the location necessary action will be taken. If the person meets with a small accident or if there is no serious threat to anyone`s life, then the alert message can be terminated by the driver by a switch provided in order to avoid wasting the valuable time of the medical rescue team. This paper is useful in detecting the accident precisely by means of both vibration sensor and Micro electro Mechanical system(MEMS or accelerometer. As there is a scope for improvement and as a future implementation we can add a wireless webcam for capturing the images which will help in providing driver`s assistance. Keywords - Accident ,Automatic Detection, Micro electro Mechanical system , Remote Alarm Device, Vehicle

  1. MRI detected prevalence of abnormalities in patients of knee pain

    Directory of Open Access Journals (Sweden)

    Ritu Mehta

    2015-10-01

    Results: In this present study 72% patients were males and 28% patients females and their ages ranging from (11-80 years. Knee pain was found common in age group 31-40 years. Menisci lesions (44% were more common as compared to ligament lesions (14% in patients of knee pain. Osteoarthritis was found in 40 % of patients of knee pain. Joint effusion and marrow edema was found with incidence of 74% and 62% respectively. 4% patients were suffering from intraarticular tumors. Conclusions: Knee pain can occur at any stage of life due to various causative factors. MRI can demonstrate the exact nature and extent of bony as well as soft tissue abnormality. This has increase the use of MRI in evaluation of patients of knee pain. [Int J Res Med Sci 2015; 3(10.000: 2572-2575

  2. Preoperative detection of colorectal liver metastases in fatty liver: MDCT or MRI?

    Energy Technology Data Exchange (ETDEWEB)

    Kulemann, Vanessa, E-mail: vanessa.kulemann@meduniwien.ac.at [Department of Radiology, Medical University of Vienna (Austria); Schima, Wolfgang [KH Goettlicher Heiland, Vienna (Austria); Tamandl, Dietmar; Kaczirek, Klaus; Gruenberger, Thomas [Department of Surgery, Medical University of Vienna (Austria); Wrba, Friedrich [Department of Pathology, Medical University of Vienna (Austria); Weber, Michael; Ba-Ssalamah, Ahmed [Department of Radiology, Medical University of Vienna (Austria)

    2011-08-15

    Objective: To compare the diagnostic value of multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) in the preoperative detection of colorectal liver metastases in diffuse fatty infiltration of the liver, associated with neoadjuvant chemotherapy. Materials and methods: Twenty preoperative tri-phasic MDCT (4-64-row, Siemens) and dynamic contrast-enhanced MRI (1.5 T or 3.0 T, Siemens) examinations of patients with colorectal cancer and liver metastases in diffuse steatosis were retrospectively evaluated. All patients underwent surgical resection for liver metastases (time interval 1-60 days). The amount of fatty infiltration of the liver was determined histopathologically by semi-quantitative percent-wise estimation and ranged from 25 to 75%. Results: Overall, 51 metastases were found by histopathology of the resected liver segments/lobes. The size of the metastases ranged from 0.4 to 13 cm, with 18 (35%) being up to 1 cm in diameter. In the overall rating, MDCT detected 33/51 lesions (65%), and MRI 45/51 (88%). For lesions up to 1 cm, MDCT detected only 2/18 (11%) and MRI 12/18 (66%). One false positive lesion was detected by MDCT. Statistical analysis showed that MRI is markedly superior to MDCT, with a statistically significant difference (p < .001), particularly for the detection of small lesions ({<=}1 cm; p < .004). There was no significant difference between the two modalities in the detection of lesions > 1 cm. Conclusion: For the detection of colorectal liver metastases after neoadjuvant chemotherapy and consecutive diffuse fatty infiltration of the liver, MRI is superior to MDCT, especially for the detection of small lesions.

  3. Diagnostic accuracy in detecting tears in the proximal biceps tendon using standard nonenhancing shoulder MRI

    Directory of Open Access Journals (Sweden)

    Dubrow SA

    2014-04-01

    Full Text Available Samuel A Dubrow,1 Jonathan J Streit,2 Yousef Shishani,2 Mark R Robbin,3 Reuben Gobezie21Department of Orthopedics, Alegent Creighton Clinic, Creighton University School of Medicine, Omaha, NE, USA; 2Department of Orthopedics, Cleveland Shoulder Institute, 3Department of Radiology, University Hospitals of Cleveland, Cleveland, OH, USABackground: There is a paucity of data in the literature evaluating the performance of noncontrast MRI in the diagnosis of partial and complete tears of the proximal portion of the long head of the biceps (LHB tendon. The objective of this study was to evaluate the accuracy of noncontrast magnetic resonance imaging (MRI compared to arthroscopy for the diagnosis of pathology involving the intra-articular portion of the LHB tendon.Methods: We conducted a retrospective review of 66 patients (mean age 57.8 years, range 43–70 years who underwent shoulder arthroscopy and evaluation of the LHB tendon after having had a noncontrast MRI of the shoulder. Biceps pathology was classified by both MRI and direct arthroscopic visualization as either normal, partial tearing, or complete rupture, and arthroscopy was considered to be the gold standard. We then determined the sensitivity, specificity, and positive- and negative-predictive values of MRI for the detection of partial and complete LHB tears.Results: MRI identified 29/66 (43.9% of patients as having a pathologic lesion of the LHB tendon (19 partial and ten complete tears while diagnostic arthroscopy identified tears in 59/66 patients (89.4%; 50 partial and 16 complete. The sensitivity and specificity of MRI for detecting partial tearing of the LHB were 27.7% and 84.2%, respectively (positive predictive value =81.2%, negative predictive value =32.0%. The sensitivity and specificity of MRI for complete tears of the LHB were 56.3% and 98.0%, respectively (positive predictive value =90.0%, negative predictive value =87.5%.Conclusion: Standard noncontrast MRI of the shoulder is limited in detecting partial tears and complete ruptures of the intra-articular LHB tendon. Surgeons may encounter pathologic lesions of the LHB tendon during arthroscopy that are not visualized on preoperative MRI.Keywords: long head biceps tendon, biceps tendon tear, MRI detection, magnetic resonance imaging, case series

  4. Abbreviated protocol for breast MRI: Are multiple sequences needed for cancer detection?

    Energy Technology Data Exchange (ETDEWEB)

    Mango, Victoria L., E-mail: vlm2125@columbia.edu [Columbia University Medical Center, Herbert Irving Pavilion, 161 Fort Washington Avenue, 10th Floor, New York, NY 10032 (United States); Memorial Sloan-Kettering Cancer Center, Breast and Imaging Center, 300 East 66th Street, New York, NY 10065 (United States); Morris, Elizabeth A., E-mail: morrise@mskcc.org [Memorial Sloan-Kettering Cancer Center, Breast and Imaging Center, 300 East 66th Street, New York, NY 10065 (United States); David Dershaw, D., E-mail: dershawd@mskcc.org [Memorial Sloan-Kettering Cancer Center, Breast and Imaging Center, 300 East 66th Street, New York, NY 10065 (United States); Abramson, Andrea, E-mail: abramsoa@mskcc.org [Memorial Sloan-Kettering Cancer Center, Breast and Imaging Center, 300 East 66th Street, New York, NY 10065 (United States); Fry, Charles, E-mail: charles_fry@nymc.edu [Memorial Sloan-Kettering Cancer Center, Breast and Imaging Center, 300 East 66th Street, New York, NY 10065 (United States); New York Medical College, 40 Sunshine Cottage Rd, Valhalla, NY 10595 (United States); Moskowitz, Chaya S. [Memorial Sloan-Kettering Cancer Center, Breast and Imaging Center, 300 East 66th Street, New York, NY 10065 (United States); Hughes, Mary, E-mail: hughesm@mskcc.org [Memorial Sloan-Kettering Cancer Center, Breast and Imaging Center, 300 East 66th Street, New York, NY 10065 (United States); Kaplan, Jennifer, E-mail: kaplanj@mskcc.org [Memorial Sloan-Kettering Cancer Center, Breast and Imaging Center, 300 East 66th Street, New York, NY 10065 (United States); Jochelson, Maxine S., E-mail: jochelsm@mskcc.org [Memorial Sloan-Kettering Cancer Center, Breast and Imaging Center, 300 East 66th Street, New York, NY 10065 (United States)

    2015-01-15

    Highlights: • Abbreviated breast MR demonstrates high sensitivity for breast carcinoma detection. • Time to perform/interpret the abbreviated exam is shorter than a standard MRI exam. • An abbreviated breast MRI could reduce costs and make MRI screening more available. - Abstract: Objective: To evaluate the ability of an abbreviated breast magnetic resonance imaging (MRI) protocol, consisting of a precontrast T1 weighted (T1W) image and single early post-contrast T1W image, to detect breast carcinoma. Materials and methods: A HIPAA compliant Institutional Review Board approved review of 100 consecutive breast MRI examinations in patients with biopsy proven unicentric breast carcinoma. 79% were invasive carcinomas and 21% were ductal carcinoma in situ. Four experienced breast radiologists, blinded to carcinoma location, history and prior examinations, assessed the abbreviated protocol evaluating only the first post-contrast T1W image, post-processed subtracted first post-contrast and subtraction maximum intensity projection images. Detection and localization of tumor were compared to the standard full diagnostic examination consisting of 13 pre-contrast, post-contrast and post-processed sequences. Results: All 100 cancers were visualized on initial reading of the abbreviated protocol by at least one reader. The mean sensitivity for each sequence was 96% for the first post-contrast sequence, 96% for the first post-contrast subtraction sequence and 93% for the subtraction MIP sequence. Within each sequence, there was no significant difference between the sensitivities among the 4 readers (p = 0.471, p = 0.656, p = 0.139). Mean interpretation time was 44 s (range 11–167 s). The abbreviated imaging protocol could be performed in approximately 10–15 min, compared to 30–40 min for the standard protocol. Conclusion: An abbreviated breast MRI protocol allows detection of breast carcinoma. One pre and post-contrast T1W sequence may be adequate for detecting breast carcinoma. These results support the possibility of refining breast MRI screening protocols.

  5. Bladder cancer: utility of MRI in detection of occult muscle-invasive disease

    Energy Technology Data Exchange (ETDEWEB)

    Rosenkrantz, Andrew B. [Dept. of Radiology, NYU Langone Medical Center, New York (United States)], E-mail: Andrew.rosenkrantz@nyumc.org; Mussi, Thais C. [Dept. of Radiology, NYU Langone Medical Center, New York (United States); Hospital Israelita Albert Einstein, Sao Paulo (Brazil); Melamed, Jonathan [Dept. of Pathology, NYU Langone Medical Center, New York (United States); Taneja, Samir S.; Huang, William C. [Dept. of Urology, Div. of Urologic Oncology, NYU Langone Medical Center, New York (United States)

    2012-07-15

    Background. The presence of muscularis propria invasion by bladder cancer is a key factor in prognosis and treatment decisions, although may be missed by biopsy due to sampling error. MRI has shown potential for detection of muscle invasion but has not specifically been evaluated for this purpose in the setting of bladder cancer patients without evidence of muscle invasion on initial biopsy. Purpose. To evaluate the role of MRI in detection of muscularis propria invasion by bladder cancer following a pathologic diagnosis of non-invasive tumor. Material and Methods. This retrospective study included 23 patients who underwent pelvic MRI following a pathologic diagnosis of bladder cancer without muscularis propria invasion and in whom additional histologic evaluation was performed following MRI. Two radiologists in consensus reviewed T2-weighted images to identify those cases suspicious for muscle invasion on MRI. The radiologists identified whether cases suspicious for invasion demonstrated disruption of the T2-hypointense muscularis layer of the bladder wall, peri-vesical fat stranding, and peri-vesical soft tissue nodularity. Findings were compared with pathologic results obtained after MRI. Results. Suspicion was raised for muscle invasion in eight of 23 cases, four of which exhibited invasion on follow-up pathology. No case without suspicion on MRI exhibited invasion on follow-up pathology. Therefore, sensitivity and specificity were 100% and 79%, respectively. Among individual findings, muscularis disruption on T2WI exhibited sensitivity of 100% and specificity of 79%, peri-vesical fat stranding exhibited sensitivity and specificity of 50% and 84%, and peri-vesical soft tissue nodularity exhibited sensitivity and specificity of 25% and 100%. Conclusion. MRI demonstrated high sensitivity for detection of muscle invasion in cases of bladder cancer without invasion on initial histologic assessment. Muscularis disruption on T2WI appeared to exhibit a better combination of sensitivity and specificity than did peri-vesical changes.

  6. Bladder cancer: utility of MRI in detection of occult muscle-invasive disease

    International Nuclear Information System (INIS)

    Background. The presence of muscularis propria invasion by bladder cancer is a key factor in prognosis and treatment decisions, although may be missed by biopsy due to sampling error. MRI has shown potential for detection of muscle invasion but has not specifically been evaluated for this purpose in the setting of bladder cancer patients without evidence of muscle invasion on initial biopsy. Purpose. To evaluate the role of MRI in detection of muscularis propria invasion by bladder cancer following a pathologic diagnosis of non-invasive tumor. Material and Methods. This retrospective study included 23 patients who underwent pelvic MRI following a pathologic diagnosis of bladder cancer without muscularis propria invasion and in whom additional histologic evaluation was performed following MRI. Two radiologists in consensus reviewed T2-weighted images to identify those cases suspicious for muscle invasion on MRI. The radiologists identified whether cases suspicious for invasion demonstrated disruption of the T2-hypointense muscularis layer of the bladder wall, peri-vesical fat stranding, and peri-vesical soft tissue nodularity. Findings were compared with pathologic results obtained after MRI. Results. Suspicion was raised for muscle invasion in eight of 23 cases, four of which exhibited invasion on follow-up pathology. No case without suspicion on MRI exhibited invasion on follow-up pathology. Therefore, sensitivity and specificity were 100% and 79%, respectively. Among individual findings, muscularis disruption on T2WI exhibited sensitivity of 100% and specificity of 79%, peri-vesical fat stranding exhibited sensitivity and specificity of 50% and 84%, and peri-vesical soft tissue nodularity exhibited sensitivity and specificity of 25% and 100%. Conclusion. MRI demonstrated high sensitivity for detection of muscle invasion in cases of bladder cancer without invasion on initial histologic assessment. Muscularis disruption on T2WI appeared to exhibit a better combination of sensitivity and specificity than did peri-vesical changes

  7. REMOTE DETECTION OF RADIOACTIVE PLUMES USING MILLIMETER WAVE TECHNOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    Barnowski, R.; Chien; H.; Gopalsami, N.

    2009-01-01

    The reprocessing of spent nuclear fuel, a common method for manufacturing weapons-grade special nuclear materials, is accompanied by the release of fi ssion products trapped within the fuel. One of these fi ssion products is a radioactive isotope of Krypton (Kr-85); a pure ?- emitter with a half-life of 10.72 years. Due to its chemical neutrality and relatively long half life, nearly all of the Kr-85 is released into the surrounding air during reprocessing, resulting in a concentration of Kr-85 near the source that is several orders of magnitude higher than the typical background (atmospheric) concentrations. This high concentration of Kr-85 is accompanied by a proportionately high increase in air ionization due to the release of beta radiation from Kr-85 decay. Millimeter wave (MMW) sensing technology can be used to detect the presence of Kr-85 induced plumes since a high concentration of ions in the air increases the radar cross section due to a combination of atmospheric phenomena. Possible applications for this technology include the remote sensing of reprocessing activities across national borders bolstering global anti-proliferation initiatives. The feasibility of using MMW radar technology to uniquely detect the presence of Kr-85 can be tested using commercial ion generators or sealed radioactive sources in the laboratory. In this paper we describe our work to derive an ion dispersion model that will describe the spatial distribution of ions from Kr-85 and other common lab sources. The types and energies of radiation emitted by isotopes Co-60 and Cs-137 were researched, and these parameters were incorporated into these dispersion models. Our results can be compared with the results of MMW detection experiments in order to quantify the relationship between radar cross section and air ionization as well as to further calibrate the MMW detection equipment.

  8. Detectability and detection rate of acute cerebral hemisphere infarcts on CT and diffusion-weighted MRI

    International Nuclear Information System (INIS)

    Our purpose was to compare the detectability and detection rate of acute ischaemic cerebral hemisphere infarcts on CT and diffusion-weighted MRI (DWI). We investigated 32 consecutive patients with acute hemisphere stroke with unenhanced CT and DWI within 6 h of stroke onset. The interval between CT and DWI ranged from 15 to 180 min (mean 60 min). Infarct detectability on CT and DWI was determined by comparing the initial CT, DWI and later reference images in a consensus reading of five independent examiners. The ''true'' detection rate was assessed by analysing all single readings. Two patients had intracerebral haematomas on DWI and CT and were excluded. There were 27 patients with ischaemic infarcts; all were visible on DWI and proven by follow-up. DWI was negative in three patients without a final diagnosis of infarct (100 % sensitivity, 100 % specificity, ? 2 = 30, P 2 = 1.48, P = 0.224). With regard to the single readings (30 examinations x 5 examiners = 150 readings), 63 CT readings were true positive and 72 false negative (sensitivity 47 %, specificity 86 %, ?2 = 2.88, P = 0.089). Of the DWI readings 128 were true positive and 7 false negative (sensitivity 95 %, specificity 87 %, ?2 = 70.67, P < 0.0001). Interobserver agreement was substantial for CT (?= 0.72, 95 % confidence interval, 0.6-0.84) and DWI (?= 0.82, 95 % confidence interval, 0.46-1). Taken together, detectability and detection rate of acute (< 6 h) hemisphere infarcts are significantly higher with DWI than with CT. (orig.)

  9. Can the painDETECT Questionnaire score and MRI help predict treatment outcome in rheumatoid arthritis

    DEFF Research Database (Denmark)

    Rifbjerg-Madsen, Signe; Christensen, Anton Wulf; Boesen, Mikael; Christensen, Robin; Danneskiold-Samsøe, Bente; Bliddal, Henning; Bartels, Else Marie; Locht, Henning; Amris, Kirstine

    2014-01-01

    contrast-enhanced MRI (DCE-MRI) is performed. METHOD AND ANALYSIS: The painDETECT Questionnaire (PDQ), originally developed to screen for a neuropathic pain component, is applied to indicate the presence of central sensitisation. Adults diagnosed with RA are included when either (A) initiating disease......-one aspect of chronic pain. In contrast, other patients report good treatment response, although imaging shows signs of inflammation, which could indicate a possible enhancement of descending pain inhibitory mechanisms. When assessing disease activity in patients with central sensitisation, the commonly used......-modifying antirheumatic drug treatment, or (B) initiating or switching to biological therapy. We anticipate that 100 patients will be enrolled, tested and reassessed after 4?months of treatment. DATA COLLECTION INCLUDES: Clinical data, conventional MRI, DCE-MRI, blood samples and patient-reported outcomes. ETHICS AND...

  10. Probability distribution function-based classification of structural MRI for the detection of Alzheimer's disease.

    Science.gov (United States)

    Beheshti, I; Demirel, H

    2015-09-01

    High-dimensional classification methods have been a major target of machine learning for the automatic classification of patients who suffer from Alzheimer's disease (AD). One major issue of automatic classification is the feature-selection method from high-dimensional data. In this paper, a novel approach for statistical feature reduction and selection in high-dimensional magnetic resonance imaging (MRI) data based on the probability distribution function (PDF) is introduced. To develop an automatic computer-aided diagnosis (CAD) technique, this research explores the statistical patterns extracted from structural MRI (sMRI) data on four systematic levels. First, global and local differences of gray matter in patients with AD compared to healthy controls (HCs) using the voxel-based morphometric (VBM) technique with 3-Tesla 3D T1-weighted MRI are investigated. Second, feature extraction based on the voxel clusters detected by VBM on sMRI and voxel values as volume of interest (VOI) is used. Third, a novel statistical feature-selection process is employed, utilizing the PDF of the VOI to represent statistical patterns of the respective high-dimensional sMRI sample. Finally, the proposed feature-selection method for early detection of AD with support vector machine (SVM) classifiers compared to other standard feature selection methods, such as partial least squares (PLS) techniques, is assessed. The performance of the proposed technique is evaluated using 130 AD and 130 HC MRI data from the ADNI dataset with 10-fold cross validation(1). The results show that the PDF-based feature selection approach is a reliable technique that is highly competitive with respect to the state-of-the-art techniques in classifying AD from high-dimensional sMRI samples. PMID:26226415

  11. A new diagnostic score to detect osteoporosis in patients undergoing lumbar spine MRI

    Energy Technology Data Exchange (ETDEWEB)

    Bandirali, Michele; Messina, Carmelo [Universita degli Studi di Milano, Scuola di Specializzazione in Radiodiagnostica, Milano (Italy); Di Leo, Giovanni; Papini, Giacomo Davide Edoardo [IRCCS Policlinico San Donato, Radiology Unit, San Donato Milanese (Italy); Sconfienza, Luca Maria; Sardanelli, Francesco [IRCCS Policlinico San Donato, Radiology Unit, San Donato Milanese (Italy); Universita degli Studi di Milano, Dipartimento di Scienze Biomediche per la Salute, San Donato Milanese (Italy); Ulivieri, Fabio Massimo [IRCCS Fondazione Ca' Granda Ospedale Maggiore Policlinico, Mineralometria Ossea Computerizzata e Ambulatorio Malattie Metabolismo Minerale e Osseo, Servizio di Medicina Nucleare, Milano (Italy)

    2015-10-15

    Signal intensity of lumbar-spine at magnetic resonance imaging (MRI) correlates to bone mineral density (BMD). Our aim was to define a quantitative MRI-based score to detect osteoporosis on lumbar-spine MRI. After Ethics Committee approval, we selected female patients who underwent both lumbar-spine MRI and dual-energy X-ray absorptiometry (DXA) and a reference group of 131 healthy females (20-29 years) who underwent lumbar-spine MRI. We measured the intra-vertebral signal-to-noise ratio in L1-L4. We introduced an MRI-based score (M-score), on the model of T-score. M-score diagnostic performance in diagnosing osteoporosis was estimated against DXA using receiver operator characteristic (ROC) analysis. We included 226 patients (median age 65 years), 70 (31 %) being osteoporotic at DXA. MRI signal-to-noise ratio correlated to BMD (r = -0.677, P < 0.001). M-score negatively correlated to T-score (r = -0.682, P < 0.001). Setting a 90 %-specificity, an M-score threshold of 5.5 was found, distinguishing osteoporosis from non-osteoporosis (sensitivity 54 %; ROC AUC 0.844). Thirty-one (14 %) patients had a fragility fracture, with osteoporosis detected in 15 (48 %) according to M-score and eight (26 %) according to T-score (P = 0.016). M-score obtained on lumbar spine MRI is a quantitative method correlating with osteoporosis. Its diagnostic value remains to be demonstrated on a large prospective cohort of patients. (orig.)

  12. A new diagnostic score to detect osteoporosis in patients undergoing lumbar spine MRI

    International Nuclear Information System (INIS)

    Signal intensity of lumbar-spine at magnetic resonance imaging (MRI) correlates to bone mineral density (BMD). Our aim was to define a quantitative MRI-based score to detect osteoporosis on lumbar-spine MRI. After Ethics Committee approval, we selected female patients who underwent both lumbar-spine MRI and dual-energy X-ray absorptiometry (DXA) and a reference group of 131 healthy females (20-29 years) who underwent lumbar-spine MRI. We measured the intra-vertebral signal-to-noise ratio in L1-L4. We introduced an MRI-based score (M-score), on the model of T-score. M-score diagnostic performance in diagnosing osteoporosis was estimated against DXA using receiver operator characteristic (ROC) analysis. We included 226 patients (median age 65 years), 70 (31 %) being osteoporotic at DXA. MRI signal-to-noise ratio correlated to BMD (r = -0.677, P < 0.001). M-score negatively correlated to T-score (r = -0.682, P < 0.001). Setting a 90 %-specificity, an M-score threshold of 5.5 was found, distinguishing osteoporosis from non-osteoporosis (sensitivity 54 %; ROC AUC 0.844). Thirty-one (14 %) patients had a fragility fracture, with osteoporosis detected in 15 (48 %) according to M-score and eight (26 %) according to T-score (P = 0.016). M-score obtained on lumbar spine MRI is a quantitative method correlating with osteoporosis. Its diagnostic value remains to be demonstrated on a large prospective cohort of patients. (orig.)

  13. Comparison of detection pattern of HCC by ferumoxide-enhanced MRI and intratumoral blood flow pattern

    International Nuclear Information System (INIS)

    We compared the detection rate and pattern of ferumoxide-enhanced magnetic resonance imaging (Fe-MRI) with the intratumoral blood flow pattern determined by CT angiography (CTA) and CT portography (CTAP) in 124 nodes (34 cases) diagnosed as hepatocellular carcinoma (HCC) or borderline HCC, based on the clinical course. Sequences to obtain a T1-weighted images (T1W), proton density-weighted images (PDW), T2-weighted images (T2W), T2*-weighted images (T2*W) were used in Fe-MRI. In nodes shown to be hypervascular on CTA, the detection rate by Fe-MRI was 69.7%. In nodes shown to be avascular by CTAP, the detection rate by Fe-MRI was 67.3%. These rates were higher than with other flow patterns. In nodes showing high signal intensity (HSI) on any sequences, arterial blood flow was increased and portal blood flow decreased in comparison with nodes without high signal intensity. All nodes showing HSI, both on Fe-MRI T2W and T2*W, were hypervascular on CTA, and portal blood flow was absent on CTAP. Nodes showing HSI on both T2*W and T2W were considered to have greater arterial blood flow and decreased portal blood flow compared with nodes appearing as HSI on T2*W, but only as iso- or low signal intensity on T2W (Mann-Whitney U-test; p<0.05). (author)

  14. Detection of Septic System Performance via Remote Sensing Technologies

    Science.gov (United States)

    Patterson, A. H.; Kuszmaul, J. S.; Harvey, C.

    2005-05-01

    Failing and improperly managed septic systems can affect water quality in their environs and cause health problems for individuals or community residents. When unchecked, failing systems can allow disease-causing pathogens to enter groundwater aquifers and pollute surface waters, contaminating drinking water, recreational waterways, and fishing grounds. Early detection of septic system leakage and failure can limit the extent of these problems. External symptoms which occur over an improperly functioning septic system can include lush or greener growth of vegetation, distress of vegetation, excessive soil moisture levels, or pooling of surface effluent. The use of remote sensing technologies coupled with attainable permit records to successfully identify these features could enable the appropriate agencies to target problem areas without extensive field inspection. High-resolution, airborne imagery was identified as having the potential to detect relative changes in soil moisture, to delineate individual leach fields, and to locate effluent discharges into water bodies. In addition, vegetation patterns responding to nutrient-rich effluent and increased soil moisture could be examined using a vegetation index. Both thermal- and color-infrared imagery were acquired for a study area in Jackson County, Mississippi, adjacent to the Gulf of Mexico. Within this coastal neighborhood known to have significant septic system failures, over 50 volunteer residents supplied information regarding the function of their systems and access to their property. Following data collection, regression methods were used to nominate the major indicators of malfunctioning systems. A ranking system for the "level of function" was derived from these analyses. A model was created which inputs data from attainable records and imagery analysis and outputs a predicted level of septic system function. The end product of this research will permit evaluation of septic system performance to be estimated using only easily obtainable data, allowing for minimal effort in the prioritization of problem areas by regulatory agencies.

  15. SQUID-Detected Microtesla MRI in the presence of Metal

    Energy Technology Data Exchange (ETDEWEB)

    Moessle, Michael; Han, Song-I.; Myers, Whittier; Lee, Seung-Kyun; Kelso, Nathan; Hatridge, Michael; Pines, Alexander; Clarke, John

    2006-09-06

    In magnetic resonance imaging (MRI) performed at fields of 1 T and above, the presence of a metal insert can distort the image because of susceptibility differences within the sample and modification of the radiofrequency fields by screening currents. Furthermore, it is not feasible to perform nuclear magnetic resonance (NMR) spectroscopy or acquire a magnetic resonance image if the sample is enclosed in a metal container. Both problems can be overcome by substantially lowering the NMR frequency. Using a microtesla imaging system operating at 2.8 kHz, with a superconducting quantum interference device (SQUID) as the signal detector, we have obtained distortion-free images of a phantom containing a titanium bar and three-dimensional images of an object enclosed in an aluminum can; in both cases high-field images are inaccessible.

  16. Magnetic resonance imaging goes postmortem: noninvasive detection and assessment of myocardial infarction by postmortem MRI

    International Nuclear Information System (INIS)

    To investigate the performance of postmortem magnetic resonance imaging (pmMRI) in identification and characterization of lethal myocardial infarction in a non-invasive manner on human corpses. Before forensic autopsy, 20 human forensic corpses were examined on a 1.5-T system for the presence of myocardial infarction. Short axis, transversal and longitudinal long axis images (T1-weighted; T2-weighted; PD-weighted) were acquired in situ. In subsequent autopsy, the section technique was adapted to short axis images. Histological investigations were conducted to confirm autopsy and/or radiological diagnoses. Nineteen myocardial lesions were detected and age staged with pmMRI, of which 13 were histologically confirmed (chronic, subacute and acute). Six lesions interpreted as peracute by pmMRI showed no macroscopic or histological finding. Five of the six peracute lesions correlated well to coronary pathology, and one case displayed a severe hypertrophic alteration. pmMRI reliably demonstrates chronic, subacute and acute myocardial infarction in situ. In peracute cases pmMRI may display ischemic lesions undetectable at autopsy and routine histology. pmMRI has the potential to substantiate autopsy and to counteract the loss of reliable information on causes of death due to the recent disappearance of the clinical autopsy. (orig.)

  17. Detection and Demarcation of Tumor using Vector Quantization in MRI images

    CERN Document Server

    Kekre, H B; Gharge, Saylee M

    2010-01-01

    Segmenting a MRI images into homogeneous texture regions representing disparate tissue types is often a useful preprocessing step in the computer-assisted detection of breast cancer. That is why we proposed new algorithm to detect cancer in mammogram breast cancer images. In this paper we proposed segmentation using vector quantization technique. Here we used Linde Buzo-Gray algorithm (LBG) for segmentation of MRI images. Initially a codebook of size 128 was generated for MRI images. These code vectors were further clustered in 8 clusters using same LBG algorithm. These 8 images were displayed as a result. This approach does not leads to over segmentation or under segmentation. For the comparison purpose we displayed results of watershed segmentation and Entropy using Gray Level Co-occurrence Matrix along with this method.

  18. Ultra-low-field MRI for the detection of liquid explosives

    Energy Technology Data Exchange (ETDEWEB)

    Espy, M; Flynn, M; Gomez, J; Hanson, C; Kraus, R; Magnelind, P; Maskaly, K; Matlashov, A; Newman, S; Owens, T; Peters, M; Sandin, H; Savukov, I; Schultz, L; Urbaitis, A; Volegov, P; Zotev, V, E-mail: espy@lanl.go [Los Alamos National Laboratory, Applied Modern Physics Group, MS D454, Los Alamos, NM 87545 (United States)

    2010-03-15

    Recently it has become both possible and practical to use magnetic resonance (MR) at magnetic fields in the range from {mu}T to mT, the so-called ultra-low-field (ULF) regime. SQUID (superconducting quantum interference device) sensor technology allows for ultra-sensitive detection while pulsed pre-polarizing fields greatly enhance the signal. The instrumentation allows for unprecedented flexibility in signal acquisition sequences and simplified MRI instrumentation. Here we present results for a new application of ULF MRI and relaxometry for the detection and characterization of liquids. We briefly describe the motivation and advantages of the ULF MR approach, and present recent results from a seven-channel ULF MRI/relaxometer system constructed to non-invasively inspect liquids at a security checkpoint for the presence of hazardous material. The instrument was deployed at the Albuquerque International Airport in December 2008, and results from that endeavor are also presented.

  19. Ultra-low-field MRI for the detection of liquid explosives

    International Nuclear Information System (INIS)

    Recently it has become both possible and practical to use magnetic resonance (MR) at magnetic fields in the range from ?T to mT, the so-called ultra-low-field (ULF) regime. SQUID (superconducting quantum interference device) sensor technology allows for ultra-sensitive detection while pulsed pre-polarizing fields greatly enhance the signal. The instrumentation allows for unprecedented flexibility in signal acquisition sequences and simplified MRI instrumentation. Here we present results for a new application of ULF MRI and relaxometry for the detection and characterization of liquids. We briefly describe the motivation and advantages of the ULF MR approach, and present recent results from a seven-channel ULF MRI/relaxometer system constructed to non-invasively inspect liquids at a security checkpoint for the presence of hazardous material. The instrument was deployed at the Albuquerque International Airport in December 2008, and results from that endeavor are also presented.

  20. Early detection of Alzheimer's disease using MRI hippocampal texture.

    Science.gov (United States)

    Sørensen, Lauge; Igel, Christian; Liv Hansen, Naja; Osler, Merete; Lauritzen, Martin; Rostrup, Egill; Nielsen, Mads

    2016-03-01

    Cognitive impairment in patients with Alzheimer's disease (AD) is associated with reduction in hippocampal volume in magnetic resonance imaging (MRI). However, it is unknown whether hippocampal texture changes in persons with mild cognitive impairment (MCI) that does not have a change in hippocampal volume. We tested the hypothesis that hippocampal texture has association to early cognitive loss beyond that of volumetric changes. The texture marker was trained and evaluated using T1-weighted MRI scans from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database, and subsequently applied to score independent data sets from the Australian Imaging, Biomarker & Lifestyle Flagship Study of Ageing (AIBL) and the Metropolit 1953 Danish Male Birth Cohort (Metropolit). Hippocampal texture was superior to volume reduction as predictor of MCI-to-AD conversion in ADNI (area under the receiver operating characteristic curve [AUC] 0.74 vs 0.67; DeLong test, p?=?0.005), and provided even better prognostic results in AIBL (AUC 0.83). Hippocampal texture, but not volume, correlated with Addenbrooke's cognitive examination score (Pearson correlation, r?=?-0.25, p?

  1. Hyperspectral remote sensing techniques for early detection of plant diseases

    Science.gov (United States)

    Krezhova, Dora; Maneva, Svetla; Zdravev, Tomas

    Hyperspectral remote sensing is an emerging, multidisciplinary field with diverse applications in Earth observation. Nowadays spectral remote sensing techniques allow presymptomatic monitoring of changes in the physiological state of plants with high spectral resolution. Hyperspectral leaf reflectance and chlorophyll fluorescence proved to be highly suitable for identification of growth anomalies of cultural plants that result from the environmental changes and different stress factors. Hyperspectral technologies can find place in many scientific areas, as well as for monitoring of plants status and functioning to help in making timely management decisions. This research aimed to detect a presence of viral infection in young pepper plants (Capsicum annuum L.) caused by Cucumber Mosaic Virus (CMV) by using hyperspectral reflectance and fluorescence data and to assess the effect of some growth regulators on the development of the disease. In Bulgaria CMV is one of the widest spread pathogens, causing the biggest economical losses in crop vegetable production. Leaf spectral reflectance and fluorescence data were collected by a portable fibre-optics spectrometer in the spectral ranges 450÷850 nm and 600-900 nm. Greenhouse experiment with pepper plants of two cultivars, Sivria (sensitive to CMV) and Ostrion (resistant to CMV) were used. The plants were divided into six groups. The first group consisted of healthy (control) plants. At growth stage 4-6 expanded leaf, the second group was inoculated with CMV. The other four groups were treated with growth regulators: Spermine, MEIA (beta-monomethyl ester of itaconic acid), ??? (benzo(1,2,3)thiadiazole-7-carbothioic acid-S-methyl ester) and Phytoxin. On the next day, the pepper plants of these four groups were inoculated with CMV. The viral concentrations in the plants were determined by the serological method DAS-ELISA. Statistical, first derivative and cluster analysis were applied and several vegetation indices were calculated for assessment the differences between the spectral data of healthy and injured (stressed) plants of two cultivars. The averaged reflectance spectra for all groups were analyzed in the most informative for green plants spectral ranges: green, red, red edge, and near infrared. Fluorescence spectra were analyzed at five characteristic wavelengths located at the maximums of the emitted radiation and at the forefronts and rear slopes. On the 7th day no visual changes in the leaves occurred but a decrease of spectral reflectance was established in the green and red ranges for all cases of two cultivars. On the 14th day an increase of the number of statistically significant differences between spectral reflectance of healthy and treated plants was observed. A shift of the red edge position to the blue region was observed for the case of treatment only with CMV. The growth regulator MEIA is with the best preventing action on the leaves. The correlation of the results from spectral analyses and the DAS-ELISA findings for presence of CMV demonstrates the efficiency and sensitivity of these remote sensing techniques for reliable diagnosis of viral infection and injuries of the plants.

  2. Involvement patterns in myotilinopathy and desminopathy detected by a novel neuromuscular whole-body MRI protocol

    International Nuclear Information System (INIS)

    Whole-body MRI (WB-MRI) has been successfully applied for oncologic and cardiovascular diagnostics, whereas imaging in myopathies usually employs dedicated protocols restricted to areas of specific interest. In this study, we propose a comprehensive neuromuscular WB-MRI protocol. Eighteen patients with degenerative and inflammatory muscle diseases were included. Whole-body imaging was performed on a 1.5-T MR system using parallel imaging. Examination time was 41:26 min. Coronal and axial T1-weighted and coronal short tau inversion recovery (STIR) sequences of the whole body were acquired. Images were analysed by two radiologists. With this protocol we could detect characteristic involvement patterns in different myofibrillar myopathies (MFMs): Patients with myotilinopathy showed frequent involvement of the rhomboid muscles (4/5), the erector spinae (5/5), the biceps femoris and the semimembranosus (5/5), while the semitendinosus was relatively spared (2/5). In contrast, in desminopathy patients the ilipsoas (3/4), the sartorius, (3/4), the gracilis (3/4) and the semitendinosus (3/4) were frequently involved, while the semimembranosus was spared (1/4). As shown for MFMs, WB-MRI is an appropriate modality to detect fatty infiltration and oedema in skeletal muscles. WB-MRI could be more useful than dedicated examinations for differential diagnosis, muscle biopsy planning and noninvasive follow-up examinations. (orig.)

  3. MRI for the detection of ureteral opening and ipsilateral kidney in children with single ectopic ureter

    International Nuclear Information System (INIS)

    To assess the usefulness of MRI in the detection of a single ectopic ureteral opening and the location and dysplastic change of ipsilateral kidney. Nine patients (mean age; 4.8 years, M:F=3:6) in whom a single ectopic ureter was suspected clinically and sonographically underwent conventional radiologic studies (IVP, VCUG, 99mTc-DM-SA scan, as well as US) and MRI. We evaluated images of the point of the ectopic ureteral opening and the location and dysplastic or hydronephrotic change of the ipsilateral kidney, and compared those findings with the endoscopic, surgical, and pathological findings. Eight patients had a unilateral single ectopic ureter and one had bilateral lesions. Seven normally positioned kidneys in six patients showed dysplastic (n=3) or hydronephrotic (n=4) change. In two patients an ectopic dysplastic kidney was located in the pelvis and one had ipsilateral renal agenesis. Conventional radiologic studies failed to reveal two ectopic dysplastic kidneys, one renal agenesis, and eight ectopic ureteral openings. In all patients, MRI clearly demonstrated the location of the kidney and ectopic ureteral opening, and dysplastic or hydronephrotic change of the kidney, and in one patient, uterine duplication. Except in two patients whose ectopic ureteral opening was not found on endoscopy, MRI findings were concordant with endoscopic and surgical findings. MRI was useful for the detection of a single ectopic ureteral opening and for demonstrating the location and dysplastic change of ipsilateral kidney

  4. MRI Brain Tumor Segmentation and Necrosis Detection Using Adaptive Sobolev Snakes.

    Science.gov (United States)

    Nakhmani, Arie; Kikinis, Ron; Tannenbaum, Allen

    2014-03-21

    Brain tumor segmentation in brain MRI volumes is used in neurosurgical planning and illness staging. It is important to explore the tumor shape and necrosis regions at different points of time to evaluate the disease progression. We propose an algorithm for semi-automatic tumor segmentation and necrosis detection. Our algorithm consists of three parts: conversion of MRI volume to a probability space based on the on-line learned model, tumor probability density estimation, and adaptive segmentation in the probability space. We use manually selected acceptance and rejection classes on a single MRI slice to learn the background and foreground statistical models. Then, we propagate this model to all MRI slices to compute the most probable regions of the tumor. Anisotropic 3D diffusion is used to estimate the probability density. Finally, the estimated density is segmented by the Sobolev active contour (snake) algorithm to select smoothed regions of the maximum tumor probability. The segmentation approach is robust to noise and not very sensitive to the manual initialization in the volumes tested. Also, it is appropriate for low contrast imagery. The irregular necrosis regions are detected by using the outliers of the probability distribution inside the segmented region. The necrosis regions of small width are removed due to a high probability of noisy measurements. The MRI volume segmentation results obtained by our algorithm are very similar to expert manual segmentation. PMID:25302005

  5. MRI brain tumor segmentation and necrosis detection using adaptive Sobolev snakes

    Science.gov (United States)

    Nakhmani, Arie; Kikinis, Ron; Tannenbaum, Allen

    2014-03-01

    Brain tumor segmentation in brain MRI volumes is used in neurosurgical planning and illness staging. It is important to explore the tumor shape and necrosis regions at di erent points of time to evaluate the disease progression. We propose an algorithm for semi-automatic tumor segmentation and necrosis detection. Our algorithm consists of three parts: conversion of MRI volume to a probability space based on the on-line learned model, tumor probability density estimation, and adaptive segmentation in the probability space. We use manually selected acceptance and rejection classes on a single MRI slice to learn the background and foreground statistical models. Then, we propagate this model to all MRI slices to compute the most probable regions of the tumor. Anisotropic 3D di usion is used to estimate the probability density. Finally, the estimated density is segmented by the Sobolev active contour (snake) algorithm to select smoothed regions of the maximum tumor probability. The segmentation approach is robust to noise and not very sensitive to the manual initialization in the volumes tested. Also, it is appropriate for low contrast imagery. The irregular necrosis regions are detected by using the outliers of the probability distribution inside the segmented region. The necrosis regions of small width are removed due to a high probability of noisy measurements. The MRI volume segmentation results obtained by our algorithm are very similar to expert manual segmentation.

  6. Utility of vaginal and rectal contrast medium in MRI for the detection of deep pelvic endometriosis

    Energy Technology Data Exchange (ETDEWEB)

    Chassang, M.; Novellas, S.; Bloch-Marcotte, C.; Chevallier, P. [Hopital Archet 2, Service d' Imagerie Diagnostique et Interventionnelle, Centre Hospitalier Regional et Universitaire de Nice, 151 route de Saint Antoine de Ginestiere, B.P. 3079, Nice Cedex 3 (France); Delotte, J.; Bongain, A. [Hopital Archet 2, Service de Gynecologie-Obstetrique, Centre Hospitalier Regional et Universitaire de Nice, 151 route de Saint Antoine de Ginestiere, B.P. 3079, Nice Cedex 3 (France); Toullalan, O. [Hopital de Cannes, Service de Gynecologie, 15 avenue des Broussailles, B.P. 264, Cannes Cedex (France)

    2010-04-15

    To study the sensitivity of MRI performed utilising vaginal and rectal opacification with ultrasound gel in the detection of deep pelvic endometriosis. This was a prospective monocentric study. All patients evaluated by the gynaecologist for pelvic pain, endometriosis or infertility were included. Axial and sagittal T2-weighted images were performed both with and without vaginal and rectal opacification with ultrasound gel. Three radiologists, all blinded, interpreted the images with a minimum of 15 days between the two readings. MRI performance with and without vaginal and rectal opacification was evaluated by calculating sensitivity, specificity and both positive and negative predictive values. Seventy-eight patients were included. Among these, 31 patients had deep pelvic endometriosis of which 24 were confirmed by laparoscopy. Seventy-six locations of deep pelvic endometriosis were discovered on MRI. For the three reviewers there was a significant improvement in sensitivity between pre- and post-contrast MRI (p < 0.0002). Opacification of the vagina and rectum significantly improved the sensitivity of MRI for the detection of deep pelvic endometriosis by expanding the vagina and rectum, thus allowing better delineation of the pelvic organs. This was especially apparent for lesions localised to the vagina and rectovaginal septum. (orig.)

  7. The accuracy of MRI in the detection of Lumbar Disc Containment

    Directory of Open Access Journals (Sweden)

    Weiner Bradley K

    2008-10-01

    Full Text Available Abstract Background MRI has proven to be an extremely valuable tool in the assessment of normal and pathological spinal anatomy. Accordingly, it is commonly used to assess containment of discal material by the outer fibers of the anulus fibrosus and posterior longitudinal ligaments. Determination of such containment is important to determine candidacy for intradiscal techniques and has prognostic significance. The accuracy of MRI in detecting containment has been insufficiently documented. Methods The MRI's of fifty consecutive patients undergoing open lumbar microdiscectomy were prospectively evaluated for disc containment by a neuroradiologist and senior spinal surgeon using criteria available in the literature and the classification of Macnab/McCulloch. An independent surgeon then performed the surgery and documented the actual containment status using the same methods. Statistical evaluation of accuracy was undertaken. Results MRI was found to be 72% sensitive, 68% specific, and 70% accurate in detecting containment status of lumbar herniated discs. Conclusion MRI may be inaccurate in assessing containment status of lumbar disc herniations in 30% of cases. Given the importance of containment for patient selection for indirect discectomy techniques and intradiscal therapies, coupled with prognostic significance; other methods to assess containment should be employed to assess containment when such alternative interventions are being considered.

  8. Development of Remote Control Laboratory for Radiation Detection via Internet

    International Nuclear Information System (INIS)

    The role of experiments in science education is essential for understanding the natural phenomena and principle related to a subject. Therefore, the remote control experiment via Internet is one of key solution for distance learners in science education. The remote experiments are also necessary for the time-consuming experiment which takes several days, collaborative experiment between distance learners, expensive laboratory equipment which is not usually available to students, experimental procedure which is dangerous, etc. In this study, we have developed a general method for a remote control laboratory system using internet and interface techniques. It is possible for students to learn the nuclear physics to control the real instruments and conduct physics experimentation with internet techniques. We proposed the remote control radiation measurement system as a sample application. This system could be useful for the monitoring near a nuclear power plants in order to improve the environment data credibility to the public

  9. Efficacy of ultrasound elastography in detecting active myositis in children: can it replace MRI?

    Energy Technology Data Exchange (ETDEWEB)

    Berko, Netanel S.; Levin, Terry L. [Montefiore Medical Center, Department of Radiology, Bronx, NY (United States); Hay, Arielle [Montefiore Medical Center, Department of Pediatrics, Division of Pediatric Rheumatology, Bronx, NY (United States); Miami Children' s Hospital, Department of Pediatrics, Miami, FL (United States); Sterba, Yonit; Wahezi, Dawn [Montefiore Medical Center, Department of Pediatrics, Division of Pediatric Rheumatology, Bronx, NY (United States)

    2015-09-15

    Juvenile idiopathic inflammatory myopathy is a rare yet potentially debilitating condition. MRI is used both for diagnosis and to assess response to treatment. No study has evaluated the performance of US elastography in the diagnosis of this condition in children. To assess the performance of compression-strain US elastography in detecting active myositis in children with clinically confirmed juvenile idiopathic inflammatory myopathy and to compare its efficacy to MRI. Children with juvenile idiopathic inflammatory myopathy underwent non-contrast MR imaging as well as compression-strain US elastography of the quadriceps muscles. Imaging findings from both modalities were compared to each other as well as to the clinical determination of active disease based on physical examination and laboratory data. Active myositis on MR was defined as increased muscle signal on T2-weighted images. Elastography images were defined as normal or abnormal based on a previously published numerical scale of muscle elastography in normal children. Muscle echogenicity was graded as normal or abnormal based on gray-scale sonographic images. Twenty-one studies were conducted in 18 pediatric patients (15 female, 3 male; age range 3-19 years). Active myositis was present on MRI in ten cases. There was a significant association between abnormal MRI and clinically active disease (P = 0.012). US elastography was abnormal in 4 of 10 cases with abnormal MRI and in 4 of 11 cases with normal MRI. There was no association between abnormal elastography and either MRI (P > 0.999) or clinically active disease (P > 0.999). Muscle echogenicity was normal in 11 patients; all 11 had normal elastography. Of the ten patients with increased muscle echogenicity, eight had abnormal elastography. There was a significant association between muscle echogenicity and US elastography (P < 0.001). The positive and negative predictive values for elastography in the determination of active myositis were 75% and 31%, respectively, with a sensitivity of 40% and specificity of 67%. Compression-strain US elastography does not accurately detect active myositis in children with juvenile idiopathic inflammatory myopathy and cannot replace MRI as the imaging standard for detecting myositis in these children. The association between abnormal US elastography and increased muscle echogenicity suggests that elastography is capable of detecting muscle derangement in patients with myositis; however further studies are required to determine the clinical significance of these findings. (orig.)

  10. Efficacy of ultrasound elastography in detecting active myositis in children: can it replace MRI?

    International Nuclear Information System (INIS)

    Juvenile idiopathic inflammatory myopathy is a rare yet potentially debilitating condition. MRI is used both for diagnosis and to assess response to treatment. No study has evaluated the performance of US elastography in the diagnosis of this condition in children. To assess the performance of compression-strain US elastography in detecting active myositis in children with clinically confirmed juvenile idiopathic inflammatory myopathy and to compare its efficacy to MRI. Children with juvenile idiopathic inflammatory myopathy underwent non-contrast MR imaging as well as compression-strain US elastography of the quadriceps muscles. Imaging findings from both modalities were compared to each other as well as to the clinical determination of active disease based on physical examination and laboratory data. Active myositis on MR was defined as increased muscle signal on T2-weighted images. Elastography images were defined as normal or abnormal based on a previously published numerical scale of muscle elastography in normal children. Muscle echogenicity was graded as normal or abnormal based on gray-scale sonographic images. Twenty-one studies were conducted in 18 pediatric patients (15 female, 3 male; age range 3-19 years). Active myositis was present on MRI in ten cases. There was a significant association between abnormal MRI and clinically active disease (P = 0.012). US elastography was abnormal in 4 of 10 cases with abnormal MRI and in 4 of 11 cases with normal MRI. There was no association between abnormal elastography and either MRI (P > 0.999) or clinically active disease (P > 0.999). Muscle echogenicity was normal in 11 patients; all 11 had normal elastography. Of the ten patients with increased muscle echogenicity, eight had abnormal elastography. There was a significant association between muscle echogenicity and US elastography (P < 0.001). The positive and negative predictive values for elastography in the determination of active myositis were 75% and 31%, respectively, with a sensitivity of 40% and specificity of 67%. Compression-strain US elastography does not accurately detect active myositis in children with juvenile idiopathic inflammatory myopathy and cannot replace MRI as the imaging standard for detecting myositis in these children. The association between abnormal US elastography and increased muscle echogenicity suggests that elastography is capable of detecting muscle derangement in patients with myositis; however further studies are required to determine the clinical significance of these findings. (orig.)

  11. Investigating Machine Learning Techniques for Detection of Depression Using Structural MRI Volumetric Features

    OpenAIRE

    Kuryati Kipli; Kouzani, Abbas Z.; Isredza Rahmi A. Hamid

    2013-01-01

    Structural MRI offers anatomical details and high sensitivity to pathological changes. It can demonstrate certain patterns of brain changes present at a structural level. Research to date has shown that volumetric analysis of brain regions has importance in depression detection. However, such analysis has had very minimal use in depression detection studies at individual level. Optimally combining various brain volumetric features/attributes, and summarizing the data into a distinctive set of...

  12. Evaluation of the potential of PET-MRI fusion for detection of liver metastases in patients with neuroendocrine tumours

    Energy Technology Data Exchange (ETDEWEB)

    Schreiter, Nils F.; Steffen, Ingo; Brenner, Winfried; Roettgen, Rainer [Charite, Department of Nuclear Medicine, Berlin (Germany); Nogami, Munenobu [Kochi University, Department of Nuclear Medicine, Kochi (Japan); Pape, Ulrich-Frank [Charite, Department of Gastroenterology, Berlin (Germany); Hamm, Bernd [Charite, Department of Radiology, Berlin (Germany)

    2012-02-15

    This study was performed to assess the role of retrospective PET-MRI fusion with Ga-68-DOTA(0)-Phe(1)-Tyr(3)-octreotide (Ga-68-DOTATOC) PET and Gd-EOB-DTPA MRI in the detection of hepatic metastases from neuroendocrine tumours (NET). Twenty-two consecutive patients with suspected liver metastases from histopathologically proven NET were examined with Gd-EOB-DTPA MRI and multiphase contrast-enhanced Ga-68-DOTATOC PET/CT. PET and MRI images were retrospectively fused using commercially available software. Two physicians experienced in nuclear medicine and radiology analysed the images to assess diagnostic confidence and characterise liver lesions. A total of 181 lesions were detected. PET-MRI showed a sensitivity of 91.2% (significantly superior to PET/CT; P < 0.05) and a specificity of 95.6% (significantly superior to MRI; P < 0.05). PET/CT had a sensitivity of 73.5% and a specificity of 88.2%. MRI had a sensitivity of 87.6% and a specificity of 86.8%. The area under the curve was 0.98 for PET-MRI, 0.96 for MRI, and 0.89 for PET/CT (P < 0.05). Retrospectively fused PET-MRI was superior to multiphase contrast-enhanced Ga-68-DOTATOC PET/CT and Gd-EOB-DTPA MRI in the detection of NET liver metastases. It was more sensitive than PET/CT and more specific than MRI. Fused PET-MRI therefore seems well suited for surgical and interventional treatment planning of NET liver metastases. (orig.)

  13. Evaluation of the potential of PET-MRI fusion for detection of liver metastases in patients with neuroendocrine tumours

    International Nuclear Information System (INIS)

    This study was performed to assess the role of retrospective PET-MRI fusion with Ga-68-DOTA(0)-Phe(1)-Tyr(3)-octreotide (Ga-68-DOTATOC) PET and Gd-EOB-DTPA MRI in the detection of hepatic metastases from neuroendocrine tumours (NET). Twenty-two consecutive patients with suspected liver metastases from histopathologically proven NET were examined with Gd-EOB-DTPA MRI and multiphase contrast-enhanced Ga-68-DOTATOC PET/CT. PET and MRI images were retrospectively fused using commercially available software. Two physicians experienced in nuclear medicine and radiology analysed the images to assess diagnostic confidence and characterise liver lesions. A total of 181 lesions were detected. PET-MRI showed a sensitivity of 91.2% (significantly superior to PET/CT; P < 0.05) and a specificity of 95.6% (significantly superior to MRI; P < 0.05). PET/CT had a sensitivity of 73.5% and a specificity of 88.2%. MRI had a sensitivity of 87.6% and a specificity of 86.8%. The area under the curve was 0.98 for PET-MRI, 0.96 for MRI, and 0.89 for PET/CT (P < 0.05). Retrospectively fused PET-MRI was superior to multiphase contrast-enhanced Ga-68-DOTATOC PET/CT and Gd-EOB-DTPA MRI in the detection of NET liver metastases. It was more sensitive than PET/CT and more specific than MRI. Fused PET-MRI therefore seems well suited for surgical and interventional treatment planning of NET liver metastases. (orig.)

  14. The detection of the dynamic renal function using MRI by gadolinium-DTPA

    International Nuclear Information System (INIS)

    The mathematical study of dynamic renal function and the simulation of renal disorder in rabbit kidney using MRI by Gd-DTPA were performed. T1 of rabbit kidney, which had been operated (complete unilateral ureteral occlusion or incomplete unilateral occlusion of renal artery) was calculated before and after intravenous injection of 0.05 mmol/kg Gd-DTPA, continuously for 90 minutes. All images were obtained by the 0.1 Tesla resistive type MRI. The changes of 1/T1 of cortex and medulla of both kidneys were calculated (MRI renogram). The 4 compartment model of bilateral kidneys was established by 6 normal MRI renogram and renal blood flow-glommelurar function parameter and tubural excration function parameter were calculated by the Runge-Kutta-Gill method and the nonlinear least squares method (Simplex method). The change of renogram pattern was observed by the mathematical change of such parameters and comparative study was performed between such mathematical simulation and practical cases. The actual change of such parameters were calculated by the experimental model of rabbit kidney. It was concluded that the change of MRI renogram pattern was sensitive for unilateral hydronephrosis, renal parenchymal dysfunction by obstructive uropathy and unilateral renal arterial stenosis. Quantitative observation of focal renal parenchymal dysfunction, which was induced by ureteral obstruction, was possible. In the near future it will be also possible to detect acculate ERBF and GFR by the measurement of T1 of human kidney. (author)

  15. MRI detection of unsuspected vertebral injury in acute spinal trauma: incidence and significance

    International Nuclear Information System (INIS)

    Objective. Multilevel spinal injury is well recognised. Previous studies reviewing the radiographs of spinal injury patients have shown an incidence of 15.2% of unsuspected spinal injury. It is recognised that magnetic resonance imaging (MRI) can identify injuries that are not demonstrated on radiographs. The objective of this study was to determine the incidence and significance of spinal injuries using MRI in comparison with radiographs.Design and patients. The radiographs and MR images of 110 acute spinal injury patients were reviewed independently of each other and the findings were then correlated to determine any unsuspected injury.Results. MRI detected vertebral body bone bruises (microtrabecular bone injury) in 41.8% of spinal injury patients which were not seen on radiographs. These bone bruises were best appreciated on sagittal short tau inversion recovery MR sequences and seen at contiguous and non-contiguous levels in relation to the primary injury.Conclusion. This level of incidence of bone bruises has not previously been appreciated. We recommend that patients undergoing MRI for an injured segment of the spine are better assessed by MRI of the entire spine at the same time to exclude further injury. (orig.)

  16. Implementation of a ferromagnetic detection system in a clinical MRI setting

    International Nuclear Information System (INIS)

    Purpose: To evaluate the implementation of a ferromagnetic detection system (FMDS) into a clinical MRI setting. Materials and methods: One thousand patients were considered for MRI safety screening using an FMDS. Equipment used was a Ferroguard® Screener (Metrasens Ltd, Malvern, Worcestershire, UK). Fully gowned patients rotated 360° in front of the FMDS in a standardized manner following traditional MRI screening methods (the use of a written questionnaire (Fig. B.1) and verbal interview. Results: Final results included 1032 individual screening events performed in 977 patients. There were 922 (94%) initial passes using the FMDS; 34 (4%) failed initial screens but passed a subsequent screen; 21 (2%) failed the initial and subsequent screens. Thus, including all screening events (n = 1032), there were 956 (93%) true negatives (TN); 21 (2%) false positives (FP) and 55 (5%) true positives (TP). No false negatives (FN) were recorded. Therefore, sensitivity was 100% and specificity was 98%. Conclusion: Implementation and correct usage of an FMDS proved to increase safety within a clinical MRI environment by alerting staff to ferromagnetic items or implants not identified using traditional MRI screening methods. An FMDS should be used as an adjunct to these methods. The information in this study pertains to the specific equipment used in this investigation. - Highlights: • Ferromagnetic detection system sensitivity in this study was 100%. • Ferromagnetic detection system specificity in this study was 98%. • The additional screening procedure had little impact on throughput ie additional time taken was minimal. • Staff training, technique and compliance is important in implementing the screening procedures. • The ferromagnetic detection system identified objects that may have demonstrated projectile, heating or artefact effects

  17. Early detection of antiangiogenic treatment responses in a mouse xenograft tumor model using quantitative perfusion MRI

    International Nuclear Information System (INIS)

    Angiogenesis plays a major role in tumor growth and metastasis, with tumor perfusion regarded as a marker for angiogenesis. To evaluate antiangiogenic treatment response in vivo, we investigated arterial spin labeling (ASL) magnetic resonance imaging (MRI) to measure tumor perfusion quantitatively. Chronic and 24-h acute treatment responses to bevacizumab were assessed by ASL and dynamic-contrast-enhanced (DCE) MRI in the A498 xenograft mouse model. After the MRI, tumor vasculature was assessed by CD34 staining. After 39 days of chronic treatment, tumor perfusion decreased to 44.8 ± 16.1 mL/100 g/min (P < 0.05), compared to 92.6 ± 42.9 mL/100 g/min in the control group. In the acute treatment study, tumor perfusion in the treated group decreased from 107.2 ± 32.7 to 73.7 ± 27.8 mL/100 g/min (P < 0.01; two-way analysis of variance), as well as compared with control group post dosing. A significant reduction in vessel density and vessel size was observed after the chronic treatment, while only vessel size was reduced 24 h after acute treatment. The tumor perfusion correlated with vessel size (r = 0.66; P < 0.005) after chronic, but not after acute treatment. The results from DCE-MRI also detected a significant change between treated and control groups in both chronic and acute treatment studies, but not between 0 and 24 h in the acute treatment group. These results indicate that tumor perfusion measured by MRI can detect early vascular responses to antiangiogenic treatment. With its noninvasive and quantitative nature, ASL MRI would be valuable for longitudinal assessment of tumor perfusion and in translation from animal models to human

  18. Rectal cancer: Possibilities of MRI in detection of local recurrence

    Directory of Open Access Journals (Sweden)

    Miučin-Vukadinović Ivana

    2008-01-01

    Full Text Available Introduction Treatment of rectal cancer, which includes periodic evaluations, may lead to earlier identification of recurrent local infiltration. Differentiation between local recurrence and other post radiation changes is frequently rather difficult. Pelvic MR examination was performed in 30 patients (20 men, 10 women at the Institute of oncology, Sremska Kamenica. All patients underwent surgical resection of rectal cancer at the same institution. Preoperative or postoperative radiation therapy was administrated in 29 patients (93%. Criteria for detection of local recurrent tumors were based on morphologic changes, such as the presence of tumor infiltration, size increase of the mass and the change of the mass shape. Recurrent tumor infiltration was detected in 50% patents. Tumors of low differentiation histological type was predominantly found within 10 months after surgery, while moderately differentiated and high differentiated types were detected within 20 months and after 20 months after resection, respectively. Pelvic MR examination represents important diagnostic modality for recurrent rectal cancer identification.

  19. Detection of cranial meningiomas: comparison of {sup 68}Ga-DOTATOC PET/CT and contrast-enhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Afshar-Oromieh, Ali; Giesel, Frederik L.; Haberkorn, Uwe; Haufe, Sabine; Kratochwil, Clemens [University Hospital of Heidelberg, Department of Nuclear Medicine, Heidelberg (Germany); Linhart, Heinz G. [DKFZ, National Center for Tumor Diseases (NCT), Heidelberg (Germany); Combs, Stephanie E. [University Hospital of Heidelberg, Department of Radiation Oncology and Therapy, Heidelberg (Germany); Podlesek, Dino [University Hospital of Dresden, Department of Neurosurgery, Dresden (Germany); Eisenhut, Michael [DKFZ, Department of Radiopharmacy, Heidelberg (Germany)

    2012-09-15

    PET imaging with somatostatin receptor ligands, such as {sup 68}Ga-DOTATOC, is a well-established method for detection and target volume definition of meningiomas prior to radiotherapy. Since DOTATOC PET delivers a higher contrast between meningiomas and surrounding tissues than MRI, we conducted a retrospective analysis to compare the diagnostic accuracy of contrast-enhanced MRI (CE-MRI) with {sup 68}Ga-DOTATOC PET/CT in patients with cranial meningiomas prior to radiotherapy. Over a period of 6 years, 134 patients (20-82 years of age, 107 women and 27 men) underwent cranial CE-MRI and {sup 68}Ga-DOTATOC PET/CT. To compare the two methods, the lesions considered typical of meningiomas visually were counted and analysed with respect to their location and SUVmax. In the 134 patients investigated by both modalities, 190 meningiomas were detected by {sup 68}Ga-DOTATOC PET/CT and 171 by CE-MRI. With knowledge of the PET/CT data, the MRI scans were reinvestigated, which led to the detection of 4 of the 19 incidental meningiomas, resulting in an overall detection rate of 92 % of the meningioma lesions that were found by PET/CT. Ga-DOTATOC PET/CT demonstrated an improved sensitivity in meningioma detection when compared to CE-MRI. Tumours adjacent to the falx cerebri, located at the skull base or obscured by imaging artefacts or calcification are particularly difficult to detect by MRI. Therefore {sup 68}Ga-DOTATOC PET/CT may provide additional information in patients with uncertain or equivocal results on MRI or could help to confirm a diagnosis of meningioma based on MRI or could help to confirm MRI-based diagnosis of meningiomas in cases of biopsy limitations. It is possible that not only radiotherapy and surgical planning, but also follow-up strategies would benefit from this imaging modality. (orig.)

  20. A boosting approach for prostate cancer detection using multi-parametric MRI

    Science.gov (United States)

    Lemaitre, Guillaume; Massich, Joan; Martí, Robert; Freixenet, Jordi; Vilanova, Joan C.; Walker, Paul M.; Sidibé, Désiré; Mériaudeau, Fabrice

    2015-04-01

    Prostate cancer has been reported as the second most frequently diagnosed men cancers in the world. In the last decades, new imaging techniques based on MRI have been developed in order to improve the diagnosis task of radiologists. In practise, diagnosis can be affected by multiple factors reducing the chance to detect potential lesions. Computer-aided detection and computer-aided diagnosis have been designed to answer to these needs and provide help to radiologists in their daily duties. In this study, we proposed an automatic method to detect prostate cancer from a per voxel manner using 3T multi-parametric Magnetic Resonance Imaging (MRI) and a gradient boosting classifier. The best performances are obtained using all multi-parametric information as well as zonal information. The sensitivity and specificity obtained are 94:7% and 93:0%, respectively and an Area Under Curve (AUC) of 0:968.

  1. Development of contaminant detection system based on ultra-low field SQUID-NMR/MRI

    Science.gov (United States)

    Tsunaki, S.; Yamamoto, M.; Hatta, J.; Hatsukade, Y.; Tanaka, S.

    2014-05-01

    We have developed an ultra-low field (ULF) NMR/MRI system using an HTS-rf-SQUID and evaluated performance of the system as a contaminant detection system for foods and drinks. In this work, we measured 1D MRIs from water samples with or without various contaminants, such as aluminum and glass balls using the system. In the 1D MRIs, changes of the MRI spectra were detected, corresponding to positions of the contaminants. We measured 2D MRIs from food samples with and without a hole. In the 2D MRIs, the hole position in the sample was well visualized. These results show that the feasibility of the system to detect and localize contaminants in foods and drinks.

  2. Development of contaminant detection system based on ultra-low field SQUID-NMR/MRI

    International Nuclear Information System (INIS)

    We have developed an ultra-low field (ULF) NMR/MRI system using an HTS-rf-SQUID and evaluated performance of the system as a contaminant detection system for foods and drinks. In this work, we measured 1D MRIs from water samples with or without various contaminants, such as aluminum and glass balls using the system. In the 1D MRIs, changes of the MRI spectra were detected, corresponding to positions of the contaminants. We measured 2D MRIs from food samples with and without a hole. In the 2D MRIs, the hole position in the sample was well visualized. These results show that the feasibility of the system to detect and localize contaminants in foods and drinks.

  3. Multiparametric MRI of the prostate. Method for early detection of prostate cancer?

    International Nuclear Information System (INIS)

    Current approaches for the early detection of prostate cancer are controversially discussed because the disease is characterized by a high incidence rate with a relatively low morbidity rate, availability of only limited prognostic markers, and continued therapy-related morbidity. Conventional morphological MRI does not play a role in early detection since small tumor foci cannot be delineated. However, if there is clinical suspicion for prostate cancer, multiparametric MRI is currently the most accurate method for detecting and characterizing suspicious lesions in the prostate. The potential to identify the so-called 'index lesion', i.e., the tumor area that is most aggressive and determines treatment, is particularly important. This information can increase the accuracy of prostate biopsy and serve as a biomarker for follow-up during active surveillance. The method may considerably contribute to the urgently required separation of clinically significant from clinically insignificant prostate cancers. (orig.)

  4. Longitudinal change detection in diffusion MRI using multivariate statistical testing on tensors.

    Science.gov (United States)

    Grigis, Antoine; Noblet, Vincent; Heitz, Fabrice; Blanc, Frédéric; de Sèze, Jérome; Kremer, Stéphane; Rumbach, Lucien; Armspach, Jean-Paul

    2012-05-01

    This paper presents a longitudinal change detection framework for detecting relevant modifications in diffusion MRI, with application to neuromyelitis optica (NMO) and multiple sclerosis (MS). The core problem is to identify image regions that are significantly different between two scans. The proposed method is based on multivariate statistical testing which was initially introduced for tensor population comparison. We use this method in the context of longitudinal change detection by considering several strategies to build sets of tensors characterizing the variability of each voxel. These strategies make use of the variability existing in the diffusion weighted images (thanks to a bootstrap procedure), or in the spatial neighborhood of the considered voxel, or a combination of both. Results on synthetic evolutions and on real data are presented. Interestingly, experiments on NMO patients highlight the ability of the proposed approach to detect changes in the normal-appearing white matter (according to conventional MRI) that are related with physical status outcome. Experiments on MS patients highlight the ability of the proposed approach to detect changes in evolving and non-evolving lesions (according to conventional MRI). These findings might open promising prospects for the follow-up of NMO and MS pathologies. PMID:22387171

  5. Thermal Hyperspectral Remote Sensing for Plant Species and Stress Detection

    Science.gov (United States)

    Schlerf, M.; Rock, G.; Ullah, S.; Gerhards, M.; Udelhoven, T.; Skidmore, A. K.

    2014-12-01

    Thermal infrared (TIR) spectroscopy offers a novel opportunity for measuring emissivity spectra of natural surfaces. Emissivity spectra are not directly measured, they first have to be retrieved from the raw measurements. Once retrieved, the spectra can be used, for example, to discriminate plant species or to detect plant stress. Knowledge of plant species distribution is essential for the sustainable management of ecosystems. Remote sensing of plant species has so far mostly been limited to data in the visible and near-infrared where, however, different species often reveal similar reflectance curves. Da Luz and Crowley showed in a recent paper that in the TIR plants indeed have distinct spectral features. Also with a certain species, subtle changes of emissivity in certain wavebands may occur, when biochemical compounds change due to osmotic adjustment induced by water stress. Here we show, that i) emissive imaging spectroscopy allows for reliable and accurate retrieval of plant emissivity spectra, ii) emissivity spectra are well suited to discriminate plant species, iii) a reduction in stomatal conductance (caused by stress) changes the thermal infrared signal. For 13 plant species in the laboratory and for 8 plant species in a field setup emissivity spectra were retrieved. A comparison shows, that for most species the shapes of the emissivity curves agree quite well, but that clear offsets between the two types of spectra exist. Discrimination analysis revealed that based on the lab spectra, 13 species could be distinguished with an average overall classification accuracy of 92% using the 6 best spectral bands. For the field spectra (8 species), a similar high OAA of 89% was achieved. Species discrimination is likely to be possible due to variations in the composition of the superficial epidermal layer of plant leaves and in internal chemical concentrations producing unique emissivity features. However, to date, which spectral feature is responsible for which chemical compound remains unclear. This new technique of TIR spectroscopy bears great potential for floristic mapping and vegetation stress monitoring, besides other applications. Future airborne and spaceborne studies, however, will have to overcome a number of challenges, for instance the cavity effect, atmospheric influences, and signal-to-noise.

  6. Mapping litter decomposition by remote-detected indicators

    Directory of Open Access Journals (Sweden)

    L. Rossi

    2006-06-01

    Full Text Available Leaf litter decomposition is a key process for the functioning of natural ecosystems. An important limiting factor for this process is detritus availability, which we have estimated by remote sensed indices of canopy green biomass (NDVI. Here, we describe the use of multivariate geostatistical analysis to couple in situ measures with hyper-spectral and multi-spectral remote-sensed data for producing maps of litter decomposition. A direct relationship between the decomposition rates in four different CORINE habitats and NDVI, calculated at different scales from Landsat ETM+ multi-spectral data and MIVIS hyper-spectral data was found. Variogram analysis was used to evaluate the spatial properties of each single variable and their common interaction. Co-variogram and co-kriging analysis of the two variables turned out to be an effective approach for decomposition mapping from remote-sensed spatial explicit data.

  7. A Method of Target Detection in Remote Sensing Image Captured based for Sensor Network

    Directory of Open Access Journals (Sweden)

    Hai Jin

    2012-02-01

    Full Text Available A refined energy constrained minimization method is developed for target detection in hyperspectral remote sensing images captured by unmanned aerial vehicles (UAVs during their surveillance missions, which has been tested in the experiment under this paper. The experiment result proves, in the detection process, this method can effectively restrain noises so far as the spectral characteristics of any potential target are known, and find sub-pixel targets out effectively from the hyperspectral remote sensing image in unknown background spectrum

  8. Automatic Cloud Detection and Removal Algorithm for MODIS Remote Sensing Imagery

    OpenAIRE

    Lingjia Gu; Ruizhi Ren; Shuang Zhang

    2011-01-01

    Cloud is one of the most common interferers in Moderate Resolution Imaging Spectrum-radiometer (MODIS) remote sensing imagery. Because of cloud interference, much important and useful information covered by cloud cannot be recovered well. How to detect and remove cloud from MODIS imagery is an important issue for wide application of remote sensing data. In general, cloud can be roughly divided into two types, namely, thin cloud and thick cloud. In order to effectively detect and eliminate clo...

  9. Detection of Spontaneous Schwannomas by MRI in a Transgenic Murine Model of Neurofibromatosis Type 2

    Directory of Open Access Journals (Sweden)

    S.M. Messerli

    2002-01-01

    Full Text Available Spontaneous schwannomas were detected by magnetic resonance imaging (MRI in a transgenic murine model of neurofibromatosis type 2 (NF2 expressing a dominant mutant form of merlin under the Schwann cell-specific PO promoter. Approximately 85% of the investigated mice showed putative tumors by 24 months of age. Specifically, 21% of the mice showed tumors in the intercostal muscles, 14% in the limb muscles, 7% in the spinal cord and spinal ganglia, 7% in the external ear, 14% in the muscle of the abdominal region, and 7% in the intestine; 66% of the female mice had uterine tumors. Multiple tumors were detected by MRI in 21% of mice. The tumors were isointense with muscle by T1-weighted MRI, showed strong enhancement following administration of gadolinium-DTPA, and were markedly hyperintense by T2-weighted MRI, all hallmarks of the clinical manifestation. Hematoxylin and eosin staining and immunohistochemistry indicated that the tumors consisted of schwannomas and Schwann cell hyperplasias. The lesions stained positively for S-100 protein and a marker antigen for the mutated transgenic NF2 protein, confirming that the imaged tumors and areas of hyperplasia were of Schwann cell origin and expressed the mutated NF2 protein. Tumors were highly infectable with a recombinant herpes simplex virus type 1 vector, hrR3, which contains the reporter gene, lacZ. The ability to develop schwannoma growth with a noninvasive imaging technique will allow assessment of therapeutic interventions.

  10. Detection of abnormalities in MRI images of brain

    International Nuclear Information System (INIS)

    Cancer is currently one of the leading causes of death. This paper presents an approach for not only the detection but also early stage of tumours can be detectable. Medical imaging technique is most commonly used to visualize the internal structure and function of the body. Magnetic Resonance Imaging provides much greater contrast between the different soft tissues of the body than computed tomography (CT) does, making it especially useful in neurological (brain), musculoskeletal, cardiovascular, and oncological (cancer) imaging. In recent years the image processing mechanisms are used widely in several medical areas for improving earlier detection and treatment stages, in which the time factor is very important to discover the disease in the patient as possible as fast, especially in various cancer tumours such as the brain cancer, lung cancer, breast cancer. We passed the available brain cancer images and its database in basic three stages to achieve more quality and accuracy in our experimental results: firstly image enhancement stage which we used low pre-processing image techniques: Gabor filter using a Gaussian rule in which produced the best resultant enhanced images. In the image segmentation stage we used thresholding segmentation mechanism by Otsu thresholding algorithm. Finally we relied on general features which help us to make a comparison between normal and abnormal images. (author)

  11. Diffusion-weighted MRI for uveal melanoma liver metastasis detection

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Mathilde; Petras, Slavomir; Servois, Vincent [Institut Curie, Department of Radiology and Nuclear Medicine, Paris (France); Mariani, Pascale; Cassoux, Nathalie [Institut Curie, Department of Surgery, Paris (France); Bidard, Francois Clement; Rodrigues, Manuel Jorge; Piperno-Neumann, Sophie [Institut Curie, Department of Medical Oncology, Paris (France); Farkhondeh, Fereshteh [Institut Curie, Department of Pathology, Paris (France)

    2015-08-15

    We aimed to assess the sensitivity of diffusion-weighted (DW) magnetic resonance (MR) imaging for the detection of pathologically confirmed uveal melanoma liver metastases (UMLM). Twenty patients who underwent complete surgical resection of their UMLM (N = 83) were included. Pre-surgery liver MR imaging included T2-weighted, T1-weighted, DW and dynamic-gadolinium-enhanced MR sequences. Two radiologists independently reviewed three sets of images (DW / morphologic-dynamic / combined) for each patient using intraoperative and pathological findings as a standard of reference. The sensitivities of the morphologic-dynamic and DW images for UMLM detection were 63 % and 59 %, respectively, for reader 1 (R1) and 64 % and 53 %, for reader 2 (R2). Sensitivity of the combined set was higher than sensitivity in the two other sets (R1:69 %, R2:67 %), but was only significantly different than the sensitivity of the DW images (McNemar test). For the three sets and the two readers, the sensitivity for UMLM smaller than 5 mm (37-46 %) was significantly lower than that for UMLM larger than 5 mm (67-90 %). The sensitivity for UMLM located in the subcapsular area (41-54 %) was significantly lower than that for intraparenchymal UMLM (68-86 %) (Chi-square test). Our study shows that the addition of DW imaging to morphologic-dynamic images does not significantly increase MR sensitivities for UMLM detection. (orig.)

  12. Detecting Brown Adipose Tissue Activity with BOLD MRI in Mice

    OpenAIRE

    Khanna, Arjun; Branca, Rosa T.

    2012-01-01

    The recent discovery of active brown adipose tissue (BAT) in adult humans and the correlation found between the activity of this tissue and resting metabolic rate strongly suggest that this tissue may be implicated in the development of obesity in humans, as it is in rodents. Despite the possible physiological role of this tissue in the onset of human obesity, few non-invasive imaging techniques to detect BAT activity in humans exist. The scope of this work is to investigate the possibility o...

  13. Armor-piercing bullet: 3-T MRI findings and identification by a ferromagnetic detection system.

    Science.gov (United States)

    Karacozoff, Alexandra M; Pekmezci, Murat; Shellock, Frank G

    2013-03-01

    The objective of this project was to evaluate magnetic resonance imaging (MRI) issues at 3 T for an armor-piercing bullet and to determine if this item could be identified using a ferromagnetic detection system. An armor-piercing bullet (.30 caliber, 7.62 × 39, copper-jacketed round, steel core; Norinco) underwent evaluation for magnetic field interactions, heating, and artifacts using standardized techniques. Heating was assessed with the bullet in a gelled-saline-filled phantom with MRI performed using a transmit/receive radio frequency body coil at a whole-body-averaged specific absorption rate of 2.9 W/kg for 15 minutes. Artifacts were characterized using T1-weighted spin echo and gradient echo pulse sequences. In addition, a special ferromagnetic detection system (Ferroguard Screener; Metrasens, Lisle, Illinois) was used in an attempt to identify this armor-piercing bullet. The findings indicated that the armor-piercing bullet showed substantial magnetic field interactions. Heating was not excessive. Artifacts were large and may create diagnostic problems if the area of interest is close to this bullet. The ferromagnetic detection system yielded a positive result. We concluded that this armor-piercing bullet is MR unsafe. Importantly, this ballistic item was identified using the particular ferromagnetic detection system utilized in this investigation, which has important implications for MRI screening and patient safety. PMID:23707130

  14. Robust detection of multiple sclerosis lesions from intensity-normalized multi-channel MRI

    Science.gov (United States)

    Karpate, Yogesh; Commowick, Olivier; Barillot, Christian

    2015-03-01

    Multiple sclerosis (MS) is a disease with heterogeneous evolution among the patients. Quantitative analysis of longitudinal Magnetic Resonance Images (MRI) provides a spatial analysis of the brain tissues which may lead to the discovery of biomarkers of disease evolution. Better understanding of the disease will lead to a better discovery of pathogenic mechanisms, allowing for patient-adapted therapeutic strategies. To characterize MS lesions, we propose a novel paradigm to detect white matter lesions based on a statistical framework. It aims at studying the benefits of using multi-channel MRI to detect statistically significant differences between each individual MS patient and a database of control subjects. This framework consists in two components. First, intensity standardization is conducted to minimize the inter-subject intensity difference arising from variability of the acquisition process and different scanners. The intensity normalization maps parameters obtained using a robust Gaussian Mixture Model (GMM) estimation not affected by the presence of MS lesions. The second part studies the comparison of multi-channel MRI of MS patients with respect to an atlas built from the control subjects, thereby allowing us to look for differences in normal appearing white matter, in and around the lesions of each patient. Experimental results demonstrate that our technique accurately detects significant differences in lesions consequently improving the results of MS lesion detection.

  15. Can MRI replace DMSA in the detection of renal parenchymal defects in children with urinary tract infections?

    Energy Technology Data Exchange (ETDEWEB)

    Kavanagh, Eoin C.; Ryan, Stephanie; McCourbrey, Siobhan; O' Connor, Rachel; Donoghue, Veronica [Children' s University Hospital, Department of Radiology, Dublin (Ireland); Awan, Atif [Children' s University Hospital, Department of Paediatrics, Dublin (Ireland)

    2005-03-01

    Renal parenchymal defects may be a consequence of urinary tract infections (UTI) in childhood. MRI is a non-radiation imaging modality compared with DMSA scanning. To compare DMSA with MRI for the detection of renal parenchymal defects in children presenting for radiological investigation after a first UTI. Both DMSA and MRI were performed at the same appointment in 37 children (aged 4 months-13 years; mean 4.5 years) with a history of UTI. Both planar and SPECT DMSA were performed. MRI of the kidneys employed axial and coronal T1-, T2- and fat-saturated T1-weighted (T1-W) sequences. Some children had imaging after IV contrast medium. The coronal fat-saturated T1-W sequence was the best sequence and it detected all the findings on MRI. MRI had a sensitivity of 77% and a specificity of 87% for the detection of a scarred kidney using DMSA as the gold standard. MRI diagnosed pyelonephritis in two children that had been interpreted as scarring on DMSA. Renal MRI using a single, coronal, fat-saturated T1-W sequence is a rapid, accurate and minimally invasive technique for the detection of renal scarring that does not employ ionizing radiation. (orig.)

  16. Can MRI replace DMSA in the detection of renal parenchymal defects in children with urinary tract infections?

    International Nuclear Information System (INIS)

    Renal parenchymal defects may be a consequence of urinary tract infections (UTI) in childhood. MRI is a non-radiation imaging modality compared with DMSA scanning. To compare DMSA with MRI for the detection of renal parenchymal defects in children presenting for radiological investigation after a first UTI. Both DMSA and MRI were performed at the same appointment in 37 children (aged 4 months-13 years; mean 4.5 years) with a history of UTI. Both planar and SPECT DMSA were performed. MRI of the kidneys employed axial and coronal T1-, T2- and fat-saturated T1-weighted (T1-W) sequences. Some children had imaging after IV contrast medium. The coronal fat-saturated T1-W sequence was the best sequence and it detected all the findings on MRI. MRI had a sensitivity of 77% and a specificity of 87% for the detection of a scarred kidney using DMSA as the gold standard. MRI diagnosed pyelonephritis in two children that had been interpreted as scarring on DMSA. Renal MRI using a single, coronal, fat-saturated T1-W sequence is a rapid, accurate and minimally invasive technique for the detection of renal scarring that does not employ ionizing radiation. (orig.)

  17. Dynamic contrast-enhanced MRI improves accuracy for detecting focal splenic involvement in children and adolescents with Hodgkin disease

    International Nuclear Information System (INIS)

    Accurate assessment of splenic disease is important for staging Hodgkin lymphoma. The purpose of this study was to assess T2-weighted imaging with and without dynamic contrast-enhanced (DCE) MRI for evaluation of splenic Hodgkin disease. Thirty-one children with Hodgkin lymphoma underwent whole-body T2-weighted MRI with supplementary DCE splenic imaging, and whole-body PET-CT before and following chemotherapy. Two experienced nuclear medicine physicians derived a PET-CT reference standard for splenic disease, augmented by follow-up imaging. Unaware of the PET-CT, two experienced radiologists independently evaluated MRI exercising a locked sequential read paradigm (T2-weighted then DCE review) and recorded the presence/absence of splenic disease at each stage. Performance of each radiologist was determined prior to and following review of DCE-MRI. Incorrect MRI findings were ascribed to reader (lesion present on MRI but missed by reader) or technical (lesion not present on MRI) error. Seven children had splenic disease. Sensitivity/specificity of both radiologists for the detection of splenic involvement using T2-weighted images alone was 57%/100% and increased to 100%/100% with DCE-MRI. There were three instances of technical error on T2-weighted imaging; all lesions were visible on DCE-MRI. T2-weighted imaging when complemented by DCE-MRI imaging may improve evaluation of Hodgkin disease splenic involvement. (orig.)

  18. Dynamic contrast-enhanced MRI improves accuracy for detecting focal splenic involvement in children and adolescents with Hodgkin disease

    Energy Technology Data Exchange (ETDEWEB)

    Punwani, Shonit; Taylor, Stuart A.; Halligan, Steve [University College London, Centre for Medical Imaging, London (United Kingdom); University College London Hospital, Department of Radiology, London (United Kingdom); Cheung, King Kenneth; Skipper, Nicholas [University College London, Centre for Medical Imaging, London (United Kingdom); Bell, Nichola; Humphries, Paul D. [University College London Hospital, Department of Radiology, London (United Kingdom); Bainbridge, Alan [University College London, Department of Medical Physics and Bioengineering, London (United Kingdom); Groves, Ashley M.; Hain, Sharon F.; Ben-Haim, Simona [University College Hospital, Institute of Nuclear Medicine, London (United Kingdom); Shankar, Ananth; Daw, Stephen [University College London Hospital, Department of Paediatrics, London (United Kingdom)

    2013-08-15

    Accurate assessment of splenic disease is important for staging Hodgkin lymphoma. The purpose of this study was to assess T2-weighted imaging with and without dynamic contrast-enhanced (DCE) MRI for evaluation of splenic Hodgkin disease. Thirty-one children with Hodgkin lymphoma underwent whole-body T2-weighted MRI with supplementary DCE splenic imaging, and whole-body PET-CT before and following chemotherapy. Two experienced nuclear medicine physicians derived a PET-CT reference standard for splenic disease, augmented by follow-up imaging. Unaware of the PET-CT, two experienced radiologists independently evaluated MRI exercising a locked sequential read paradigm (T2-weighted then DCE review) and recorded the presence/absence of splenic disease at each stage. Performance of each radiologist was determined prior to and following review of DCE-MRI. Incorrect MRI findings were ascribed to reader (lesion present on MRI but missed by reader) or technical (lesion not present on MRI) error. Seven children had splenic disease. Sensitivity/specificity of both radiologists for the detection of splenic involvement using T2-weighted images alone was 57%/100% and increased to 100%/100% with DCE-MRI. There were three instances of technical error on T2-weighted imaging; all lesions were visible on DCE-MRI. T2-weighted imaging when complemented by DCE-MRI imaging may improve evaluation of Hodgkin disease splenic involvement. (orig.)

  19. Detecting brain activation in fMRI using group random walker.

    Science.gov (United States)

    Ng, Bernard; Hamarneh, Ghassan; Abugharbieh, Rafeef

    2010-01-01

    Due to the complex noise structure of functional magnetic resonance imaging (fMRI) data, methods that rely on information within a single subject often results in unsatisfactory functional segmentation. We thus propose a new graph-theoretic method, "Group Random Walker" (GRW), that integrates group information in detecting single-subject activation. Specifically, we extend each subject's neighborhood system in such a way that enables the states of both intra- and inter-subject neighbors to be regularized without having to establish a one-to-one voxel correspondence as required in standard fMRI group analysis. Also, the GRW formulation provides an exact, unique closed-form solution for jointly estimating the probabilistic activation maps of all subjects with global optimality guaranteed. Validation is performed on synthetic and real data to demonstrate GRW's superior detection power over standard analysis methods. PMID:20879332

  20. Late widespread skeletal metastases from myxoid liposarcoma detected by MRI only

    Directory of Open Access Journals (Sweden)

    O'Donnell Paul

    2008-06-01

    Full Text Available Abstract Background Myxoid liposarcoma is the second most commonly occurring sub-type of liposarcomas. In contrast to other soft tissue sarcomas, it is known to have a tendency to spread toward extrapulmonary sites, such as soft tissues, retroperitoneum, and the peritoneal surface. Bony spread, however, is not as common. Case presentation We report an unusual case of diffuse skeletal metastases from myxoid liposarcoma occurring 13 years after treatment of the primary tumour in the left lower limb. The skeletal spread of the disease was demonstrated on MRI only after other imaging modalities (plain radiography, CT and TC99 bone scans had failed to detect these metastases. Conclusion MRI is an extremely sensitive and specific screening tool in the detection of skeletal involvement in these types of sarcomas, and therefore, should be a part of the staging process.

  1. Detection of electroporation-induced membrane permeabilization states in the brain using diffusion-weighted MRI

    DEFF Research Database (Denmark)

    Mahmood, Faisal; Hansen, Rasmus H

    2015-01-01

    Background. Tissue permeabilization by electroporation (EP) is a promising technique to treat certain cancers. Non-invasive methods for verification of induced permeabilization are important, especially in deep-seated cancers. In this study we evaluated diffusion-weighted magnetic resonance imaging (DW-MRI) as a quantitative method for detecting EP-induced membrane permeabilization of brain tissue using a rat brain model. Material and methods. Fifty-four anesthetized Sprague-Dawley male rats were electroporated in the right hemisphere, using different voltage levels to induce no permeabilization (NP), transient membrane permeabilization (TMP), and permanent membrane permeabilization (PMP), respectively. DW-MRI was acquired 5 minutes, 2 hours, 24 hours and 48 hours after EP. Histology was performed for validation of the permeabilization states. Tissue content of water, Na(+), K(+), Ca(2+), and extracellular volume were determined. The Kruskal-Wallis test was used to compare the DW-MRI parameters, apparent diffusion coefficient (ADC) and kurtosis, at different voltage levels. The two-sample Mann- Whitney test with Holm's Bonferroni correction was used to identify pairs of significantly different groups. The study was approved by the Danish Animal Experiments Inspectorate. Results and conclusion. Results showed significant difference in the ADC between TMP and PMP at 2 hours (p < 0.001) and 24 hours (p < 0.05) after EP. Kurtosis was significantly increased both at TMP (p < 0.05) and PMP (p < 0.001) 5 minutes after EP, compared to NP. Kurtosis was also significantly higher at 24 hours (p < 0.05) and 48 hours (p < 0.05) at PMP compared to NP. Physiological parameters indicated correlation with the permeabilization states, supporting the DW-MRI findings. We conclude that DW-MRI is capable of detecting EP-induced permeabilization of brain tissue and to some extent of differentiating NP, TMP and PMP using appropriate scan timing.

  2. The detection of the dynamic renal function using MRI by gadolinium-DTPA

    International Nuclear Information System (INIS)

    A study of the dynamic renal function in rabbits using MRI by Gd-DTPA was performed. T1 of rabbit kidney, which had been operated (complete unilateral ureteral occlusion or incomplete unilateral occulusion of the renal artery) was calculated before and after intravenous injection of 0.05 mmol/kg of Gd-DTPA, continuously for 90 minutes. All images were obtained by the 0.1 Tesla resistive type MRI. The changes of 1/T1 of cortex and medulla of both kidneys were plotted (MRI renography). T1 of renal cortex was shorter than that of renal medulla in normal kidney by plain T1 image, and T1 of both parts of the kidney was elongated day after day in unilateral hydronephrosis without contrast media. The peak was marked 2 minutes after injection of Gd-DTPA and the half-life of the excretory phase was 30 minute in the cortex and 40 minute in the medulla in normal MRI renography. The operated site was higher than the opposite-site in the change of 1/T1 (the peak value-the value before administration) immediately after operation, but after 24 hours the operated site was lower, in hydronephrotic rabbits. The renal parenchymal damage due to ureteral obstruction was accurately and sensitively detected. In renal arterial stenosis, the change of 1/T1 was minimal in the operated-site because of the reduction of excretion of contrast media due to decrease of GFR. It was concluded that MRI renography was able to detect regional dynamic renal function and it was expected that calculation of ERBF, GFR and tubular excretory function was quantitively examined by mathematical analysis. (author)

  3. Detecting functional connectivity change points for single-subject fMRI data

    OpenAIRE

    IvorCribben; TorWager; MartinLindquist

    2013-01-01

    Recently in functional magnetic resonance imaging (fMRI) studies there has been an increased interest in understanding the dynamic manner in which brain regions communicate with one another, as subjects perform a set of experimental tasks or as their psychological state changes. Dynamic Connectivity Regression (DCR) is a data-driven technique used for detecting temporal change points in functional connectivity between brain regions where the number and location of the change points are unkno...

  4. Detecting functional connectivity change points for single-subject fMRI data

    OpenAIRE

    Cribben, Ivor; Wager, Tor D.; Lindquist, Martin A.

    2013-01-01

    Recently in functional magnetic resonance imaging (fMRI) studies there has been an increased interest in understanding the dynamic manner in which brain regions communicate with one another, as subjects perform a set of experimental tasks or as their psychological state changes. Dynamic Connectivity Regression (DCR) is a data-driven technique used for detecting temporal change points in functional connectivity between brain regions where the number and location of the change points are unknow...

  5. fMRI investigation of visual change detection in adults with autism?

    OpenAIRE

    Clery, H.; F. Andersson; F. Bonnet-Brilhault; Philippe, A.; Wicker, B.; Gomot, M.

    2013-01-01

    People with autism spectrum disorders (ASD) may show unusual reactions to unexpected changes that appear in their environment. Although several studies have highlighted atypical auditory change processing in ASD, little is known in this disorder about the brain processes involved in visual automatic change detection. The present fMRI study was designed to localize brain activity elicited by unexpected visual changing stimuli in adults with ASD compared to controls. Twelve patients with ASD an...

  6. Intra-articular membranous interposition detected by MRI in developmental dysplasia of the hip

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, W.; Itoi, Eiji; Sato, Kozo [Akita Univ. (Japan). Dept. of Orthopedic Surgery

    2000-12-01

    Intra-articular membranous interposition was detected by MRI in the hip joint with residual subluxation of a girl aged 5 years 10 months. This structure, which had low signal intensity on both T1- and T2-weighted images, separated the femoral head from the acetabulum. Histological examination revealed chondrometaplasia, which suggested that this interposition might be transformed to a surface cartilaginous tissue of the secondary acetabulum often observed in residual subluxation of the hip. (orig.)

  7. Intra-articular membranous interposition detected by MRI in developmental dysplasia of the hip

    International Nuclear Information System (INIS)

    Intra-articular membranous interposition was detected by MRI in the hip joint with residual subluxation of a girl aged 5 years 10 months. This structure, which had low signal intensity on both T1- and T2-weighted images, separated the femoral head from the acetabulum. Histological examination revealed chondrometaplasia, which suggested that this interposition might be transformed to a surface cartilaginous tissue of the secondary acetabulum often observed in residual subluxation of the hip. (orig.)

  8. Non destructive assessment of watercore in apples using MRI. Disorder detection with HR-MAS

    OpenAIRE

    Melado Herreros, Angela; Barreiro Elorza, Pilar; Val, Jesús; Blanco, Alvaro; Ruiz Cabello Osuna, Jesus Maria; Rodriguez, Ignacio

    2010-01-01

    This work was carried out in the frame of the European project InsideFood (Integrated sensing and imaging devices for designing, monitoring and controlling microstructure of foods). The aim of this project is to provide technological solutions for exploring the microstructure of foods, by the development, combination and application of different non destructive techniques: X-ray CT, OCT, MRI, NMR, TRS and SRS. Nuclear magnetic resonance (NMR) was used in order to detect waterco...

  9. Crop stress detection and classification using hyperspectral remote sensing

    Science.gov (United States)

    Irby, Jon Trenton

    Agricultural production has observed many changes in technology over the last 20 years. Producers are able to utilize technologies such as site-specific applicators and remotely sensed data to assist with decision making for best management practices which can improve crop production and provide protection to the environment. It is known that plant stress can interfere with photosynthetic reactions within the plant and/or the physical structure of the plant. Common types of stress associated with agricultural crops include herbicide induced stress, nutrient stress, and drought stress from lack of water. Herbicide induced crop stress is not a new problem. However, with increased acreage being planting in varieties/hybrids that contain herbicide resistant traits, herbicide injury to non-target crops will continue to be problematic for producers. With rapid adoption of herbicide-tolerant cropping systems, it is likely that herbicide induced stress will continue to be a major concern. To date, commercially available herbicide-tolerant varieties/hybrids contain traits which allow herbicides like glyphosate and glufosinate-ammonium to be applied as a broadcast application during the growing season. Both glyphosate and glufosinate-ammonium are broad spectrum herbicides which have activity on a large number of plant species, including major crops like non-transgenic soybean, corn, and cotton. Therefore, it is possible for crop stress from herbicide applications to occur in neighboring fields that contain susceptible crop varieties/hybrids. Nutrient and moisture stress as well as stress caused by herbicide applications can interact to influence yields in agricultural fields. If remotely sensed data can be used to accurately identify specific levels of crop stress, it is possible that producers can use this information to better assist them in crop management to maximize yields and protect their investments. This research was conducted to evaluate classification of specific crop stresses utilizing hyperspectral remote sensing. Key words: crop stress, herbicide drift, remote sensing

  10. Detecting Alzheimer’s disease by morphological MRI using hippocampal grading and cortical thickness

    DEFF Research Database (Denmark)

    Eskildsen, Simon Fristed; Coupé, Pierrick

    2014-01-01

    Structural MRI is an important imaging biomarker in Alzheimer’s disease as the cerebral atrophy has been shown to closely correlate with cogni-tive symptoms. Recognizing this, numerous methods have been developed for quantifying the disease related atrophy from MRI over the past decades. Special effort has been dedicated to separate AD related modifications from normal ag-ing for the purpose of early detection and prediction. Several groups have re-ported promising results using automatic methods; however, it is very difficult to compare these methods due to varying cohorts and different validation frameworks. To address this issue, the public challenge on Computer-Aided Di-agnosis of Dementia based on structural MRI data (CADDementia) was pro-posed. The challenge calls for accurate classification of 354 MRI scans collect-ed among AD patients, subjects with mild cognitive impairment and cognitively normal control. The true diagnosis is hidden from the participating groups, thus making the validation truly objective. This paper describes our proposed meth-od to automatically classify the challenge data along with a validation on 30 scans with known diagnosis also provided for the challenge.

  11. Clinical evaluation of asymptomatic sinus disease detected by MRI

    Energy Technology Data Exchange (ETDEWEB)

    Iwabuchi, Yasuo; Hanamure, Yutaka; Hirota, Johji; Ohyama, Masaru [Kagoshima Univ. (Japan). Faculty of Medicine

    1994-12-01

    The detection of lesions of the paranasal sinuses as incidental findings during magnetic resonance imaging of patients suspected of intracranial disease who have no nasal symptoms has been far more common than we expected. The present study was performed on 325 patients with a mean age of 60.7 years. Medical histories were taken whether they had any nasal symptoms or not. Asymptomatic sinus disease was present in 41.6% of the 257 patients who had no nasal symptoms, and 9.7% of the patients had either marked mucosal thickening, excessive fluid or polyps in the maxillary sinuses. Although the mean age of these patients was comparatively high, we can infer that 1 in 10 have relatively severe sinus lesions. Mucociliary transport time was measured using the saccharin method in 15 patients who had sinus disease but no nasal symptoms. The mean transport time was 15.6 minutes and within normal limits. Routine ENT examination revealed no lesions in the nasal cavity of any of the subjects. We classified the patients with asymptomatic sinus disease into two groups -- group A: patients with sinus disease associated with some nasal manifestations but who did not complain about them, and group B: patients who had sinus disease but did not have any nasal problems. Group B represents genuine asymptomatic sinus disease in the narrow sense. Most asymptomatic patients in this study appeared to belong to group B. They had some sinus disease, but because their mucociliary function in their nasal cavity was normal, they did not have any nasal symptoms. When we find patients with asymptomatic sinus disease, we have to determine which group they belong to by examining their nasal cavity and measuring their saccharin time. Patients in group A should be medically treated, but those in group B should be followed without medical treatment. (author).

  12. Clinical evaluation of asymptomatic sinus disease detected by MRI

    International Nuclear Information System (INIS)

    The detection of lesions of the paranasal sinuses as incidental findings during magnetic resonance imaging of patients suspected of intracranial disease who have no nasal symptoms has been far more common than we expected. The present study was performed on 325 patients with a mean age of 60.7 years. Medical histories were taken whether they had any nasal symptoms or not. Asymptomatic sinus disease was present in 41.6% of the 257 patients who had no nasal symptoms, and 9.7% of the patients had either marked mucosal thickening, excessive fluid or polyps in the maxillary sinuses. Although the mean age of these patients was comparatively high, we can infer that 1 in 10 have relatively severe sinus lesions. Mucociliary transport time was measured using the saccharin method in 15 patients who had sinus disease but no nasal symptoms. The mean transport time was 15.6 minutes and within normal limits. Routine ENT examination revealed no lesions in the nasal cavity of any of the subjects. We classified the patients with asymptomatic sinus disease into two groups -- group A: patients with sinus disease associated with some nasal manifestations but who did not complain about them, and group B: patients who had sinus disease but did not have any nasal problems. Group B represents genuine asymptomatic sinus disease in the narrow sense. Most asymptomatic patients in this study appeared to belong to group B. They had some sinus disease, but because their mucociliary function in their nasal cavity was normal, they did not have any nasal symptoms. When we find patients with asymptomatic sinus disease, we have to determine which group they belong to by examining their nasal cavity and measuring their saccharin time. Patients in group A should be medically treated, but those in group B should be followed without medical treatment. (author)

  13. Time-delayed contrast-enhanced MRI improves detection of brain metastases and apparent treatment volumes.

    Science.gov (United States)

    Kushnirsky, Marina; Nguyen, Vinh; Katz, Joel S; Steinklein, Jared; Rosen, Lisa; Warshall, Craig; Schulder, Michael; Knisely, Jonathan P S

    2016-02-01

    OBJECT Contrast-enhanced MRI is the preeminent diagnostic test for brain metastasis (BM). Detection of BMs for stereotactic radiosurgery (SRS) planning may improve with a time delay following administration of a high-relaxivity agent for 1.5-T and 3-T imaging systems. Metastasis detection with time-delayed MRI was evaluated in this study. METHODS Fifty-three volumetric MRI studies from 38 patients undergoing SRS for BMs were evaluated. All studies used 0.1-mmol/kg gadobenate dimeglumine (MultiHance; Bracco Diagnostics) immediately after injection, followed by 2 more axial T1-weighted sequences after 5-minute intervals (final image acquisition commenced 15 minutes after contrast injection). Two studies were motion limited and excluded. Two hundred eighty-seven BMs were identified. The studies were randomized and examined separately by 3 radiologists, who were blinded to the temporal sequence. Each radiologist recorded the number of BMs detected per scan. A Wilcoxon signed-rank test compared BM numbers between scans. One radiologist determined the scan on which BMs were best defined. All confirmed, visible tumors were contoured using iPlan RT treatment planning software on each of the 3 MRI data sets. A linear mixed model was used to analyze volume changes. RESULTS The interclass correlations for Scans 1, 2, and 3 were 0.7392, 0.7951, and 0.7290, respectively, demonstrating excellent interrater reliability. At least 1 new lesion was detected in the second scan as compared with the first in 35.3% of subjects (95% CI 22.4%-49.9%). The increase in BM numbers between Scans 1 and 2 ranged from 1 to 10. At least 1 new lesion was detected in the third scan as compared with the second in 21.6% of subjects (95% CI 11.3%-35.3%). The increase in BM numbers between Scans 2 and 3 ranged from 1 to 9. Between Scans 1 and 3, additional tumors were seen on 43.1% of scans (increase ranged from 1 to 14). The median increase in tumor number for all comparisons was 1. There was a significant increase in number of BMs detected from Scan 1 to Scan 2 (p BMs, delayed MRI after contrast injection revealed more targets that needed treatment. In addition, apparent treatment volumes increased with a time delay. To avoid missing tumors that could be treated at the time of planned SRS and resultant "treatment failures," the authors recommend that postcontrast MR images be acquired between 10 and 15 minutes after injection in patients undergoing SRS for treatment of BMs. PMID:26361281

  14. New hybrid remote sensing method using HPM illumination/IR detection for mine detection

    Science.gov (United States)

    Khanna, Shyam M.; Paquet, Francois; Apps, Rene; Seregelyi, Joe S.

    1998-09-01

    A new hybrid remote-sensing method using active high-power microwave (HPM) illumination and passive infrared (IR) detection is presented for the detection of shallow buried landmines. A 2.45 GHz, 5 kW microwave source was used for illumination. The thermal signature of the mine at the soil surface was detected in the 8 - 12 micrometer region both in near real-time as well as after a brief time-delay following illumination. The thermal signature at the soil surface is primarily made up of two components. A thermal signature occurs at the soil surface in near real-time due to the interference of the incident beam and the beam reflected by the mine. A second thermal signature is generated when the variations in heating due to differential microwave absorption by the mine and the surrounding soil is conducted upwards from the mine location to the surface. Both signatures are dependent on the complex dielectric constants of the mine and the soil. Results will be presented from laboratory experiments and field trials with different types of metallic and non-metallic mine surrogates, dummy mines without explosives and live mines with explosives but without fuses.

  15. Airport detection in remote sensing images: a method based on saliency map

    OpenAIRE

    Wang, Xin; Lv, Qi; Wang, Bin; Zhang, Liming(Physics Department, Syracuse University, Syracuse, NY 13244-1130, USA)

    2012-01-01

    The detection of airport attracts lots of attention and becomes a hot topic recently because of its applications and importance in military and civil aviation fields. However, the complicated background around airports brings much difficulty into the detection. This paper presents a new method for airport detection in remote sensing images. Distinct from other methods which analyze images pixel by pixel, we introduce visual attention mechanism into detection of airport and improve the efficie...

  16. Incidental memory encoding assessed with signal detection theory and functional magnetic resonance imaging (fMRI

    Directory of Open Access Journals (Sweden)

    Benjamin Clemens

    2015-11-01

    Full Text Available 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 versus 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 versus LP during incidental encoding for remembered versus forgotten items (hits > misses in the insula / temporo-parietal junction (TPJ and the 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 between HP and LP.

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

    Science.gov (United States)

    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 between HP and LP. PMID:26635557

  18. A Novel Datamining Based Approach for Remote Intrusion Detection

    Directory of Open Access Journals (Sweden)

    Renu Deepti.S, Loshma.G

    2012-06-01

    Full Text Available Today, as information systems are more open to the Internet,attacks and intrusions are also increasing rapidly so the importance of secure networks is also vital. New intelligent Intrusion Detection Systems which are based on sophisticated algorithms are in demand.Intrusion Detection System (IDS is an important detection used as a countermeasure to preserve data integrity and system availability from attacks. It is a combination of software and hardware that attempts to perform intrusion detection.In data mining based intrusion detection system, we should make use of particular domain knowledge in relation to intrusion detection in order to efficiently extract relative rules from large amounts of records.This paper proposes boosting method for intrusion detection and it is possible to detect the intrusions in all the Systems, without installing the Software in client System (like client-server via Web service (Apache tomcat by using the ip address of the client system.

  19. Modeling Chemical Detection Sensitivities of Active and Passive Remote Sensing Systems

    Energy Technology Data Exchange (ETDEWEB)

    Scharlemann, E T

    2003-07-28

    During nearly a decade of remote sensing programs under the auspices of the U. S. Department of Energy (DOE), LLNL has developed a set of performance modeling codes--called APRS--for both Active and Passive Remote Sensing systems. These codes emphasize chemical detection sensitivity in the form of minimum detectable quantities with and without background spectral clutter and in the possible presence of other interfering chemicals. The codes have been benchmarked against data acquired in both active and passive remote sensing programs at LLNL and Los Alamos National Laboratory (LANL). The codes include, as an integral part of the performance modeling, many of the data analysis techniques developed in the DOE's active and passive remote sensing programs (e.g., ''band normalization'' for an active system, principal component analysis for a passive system).

  20. Remote Gas Detection Using Millimeter-Wave Spectroscopy for Counter Bio-Terrorism

    Science.gov (United States)

    Szlazak, Matthew; Yam, Seng Yiep; Majstorovic, Dejan; Hansen, Hedley J.; Abbott, Derek

    2002-11-01

    The mm-wave (10-110 GHz) frequency band contains the fundamental rotational resonance frequencies of many molecular gases composed of carbon, nitrogen, oxygen and sulfur. The high specificity of the rotational spectra to organic molecules affords mm-wave spectroscopy having potential use in remotely sensing atmospheric pollutants and the detection of airborne chemicals is gaining importance for arms control treaty verification, intelligence collection and environmental monitoring. This paper considers RF receiver systems for remote chemical detection measurements based on mm-wave spectral line emissions. It discusses the design, performance and operation of specific receiving systems for detecting the presence of ammonia in laboratory based transmit-and-receive experiments.

  1. Limited role of gadolinium to detect active sacroiliitis on MRI in juvenile spondyloarthritis

    Energy Technology Data Exchange (ETDEWEB)

    Herregods, N.; Leus, A.; Verstraete, K.; Jans, L. [Ghent University Hospital, Department of Radiology and Medical Imaging, Ghent (Belgium); Jaremko, J.L. [University of Alberta Hospital, Department of Radiology and Diagnostic Imaging, Edmonton, AB (Canada); Baraliakos, X. [Ruhr-University Bochum, Rheumazentrum Ruhrgebiet, Herne (Germany); Dehoorne, J. [Ghent University Hospital, Department of Pediatric Rheumatology, Ghent (Belgium)

    2015-11-15

    The aim of this study is to determine the added diagnostic value of contrast-enhanced (CE) magnetic resonance imaging (MRI) compared to routine non contrast-enhanced MRI to detect active sacroiliitis in clinically juvenile spondyloarthritis (JSpA). A total of 80 children clinically suspected for sacroiliitis prospectively underwent MRI of the sacroiliac (SI) joints. Axial and coronal T1-weighted (T1), Short-tau inversion recovery (STIR) and fat-saturated T1-weighted gadolinium-DTPA (Gd) contrast-enhanced (T1/Gd) sequences were obtained. The presence of bone marrow edema (BME), capsulitis, enthesitis, high intra-articular STIR signal, synovial enhancement and a global diagnostic impression of the MRI for diagnosis of sacroiliitis was recorded. STIR and T1/Gd sequences had 100 % agreement for depiction of BME, capsulitis and enthesitis. High intra-articular STIR signal was seen in 18/80 (22.5 %) patients, 15 (83 %) of whom also showed synovial enhancement in the T1/Gd sequence. Sensitivity (SN) and specificity (SP) for a clinical diagnosis of JSpA were similar for high STIR signal (SN = 33 %, SP = 85 %) and T1/Gd synovial enhancement (SN = 36 %, SP = 92 %). Positive likelihood ratio (LR+) for JSpA was twice as high for synovial enhancement than high STIR signal (4.5 compared to 2.2). Global diagnostic impression was similar (STIR: SN = 55 %, SP = 87 %, LR + =4.2; T1/Gd: SN = 55 %, SP = 92 %, LR + = 6.9). MRI without contrast administration is sufficient to identify bone marrow edema, capsulitis and retroarticular enthesitis as features of active sacroiliitis in juvenile spondyloarthritis. In selected cases when high STIR signal in the joint is the only finding, gadolinium-enhanced images may help to confirm the presence of synovitis. (orig.)

  2. Aircraft target onboard detecting technology via Circular Information Matching method for remote sensing satellite

    Science.gov (United States)

    Xiao, Huachao; Zhou, Quan; Li, Li

    2015-10-01

    Image information onboard processing is one o f important technology to rapidly achieve intelligence for remote sensing satellites. As a typical target, aircraft onboard detection has been getting more attention. In this paper, we propose an efficient method of aircraft detection for remote sensing satellite onboard processing. According to the feature of aircraft performance in remote sensing image, the detection algorithm consists of two steps: First Salient Object Detection (SOD) is employed to reduce the amount of calculation on large remote sensing image. SOD uses Gabor filtering and a simple binary test between pixels in a filtered image. White points are connected as regions. Plane candidate regions are screened from white regions by area, length and width of connected region. Next a new algorithm, called Circumferential Information Matching method, is used to detect aircraft on candidate regions. The results of tests show circumference curve around the plane center is stable shape, so the candidate region can be accurately detecting with this feature. In order to rotation invariant, we use circle matched filter to detect target. And discrete fast Fourier transform (DFFT) is used to accelerate and reduce calculation. Experiments show the detection accuracy rate of proposed algorithm is 90% with less than 0.5s processing time. In addition, the calculation of the proposed method through quantitative anglicized is very small. Experimental results and theoretical analysis show that the proposed method is reasonable and highly-efficient.

  3. Remote detection of single emitters via optical waveguides

    Science.gov (United States)

    Then, Patrick; Razinskas, Gary; Feichtner, Thorsten; Haas, Philippe; Wild, Andreas; Bellini, Nicola; Osellame, Roberto; Cerullo, Giulio; Hecht, Bert

    2014-05-01

    The integration of lab-on-a-chip technologies with single-molecule detection techniques may enable new applications in analytical chemistry, biotechnology, and medicine. We describe a method based on the reciprocity theorem of electromagnetic theory to determine and optimize the detection efficiency of photons emitted by single quantum emitters through truncated dielectric waveguides of arbitrary shape positioned in their proximity. We demonstrate experimentally that detection of single quantum emitters via such waveguides is possible, confirming the predicted behavior of the detection efficiency. Our findings blaze the trail towards efficient lensless single-emitter detection compatible with large-scale optofluidic integration.

  4. High Frequency Remote Monitoring of Parkinson's Disease via Smartphone: Platform Overview and Medication Response Detection

    OpenAIRE

    Zhan, Andong; Little, Max A.; Harris, Denzil A.; Abiola, Solomon O.; Dorsey, E. Ray; Saria, Suchi; Terzis, Andreas

    2016-01-01

    Objective: The aim of this study is to develop a smartphone-based high-frequency remote monitoring platform, assess its feasibility for remote monitoring of symptoms in Parkinson's disease, and demonstrate the value of data collected using the platform by detecting dopaminergic medication response. Methods: We have developed HopkinsPD, a novel smartphone-based monitoring platform, which measures symptoms actively (i.e. data are collected when a suite of tests is initiated by the individual at...

  5. Progress on detection of liquid explosives using ultra-low field MRI

    Energy Technology Data Exchange (ETDEWEB)

    Espy, Michelle A [Los Alamos National Laboratory; Matlashov, Andrei N [Los Alamos National Laboratory; Volegov, Petr L [Los Alamos National Laboratory; Schuttz, Larry M [Los Alamos National Laboratory; Baguisa, Shermiyah [Los Alamos National Laboratory; Dunkerley, David [Los Alamos National Laboratory; Magnelind, Per [Los Alamos National Laboratory; Owens, Tuba [Los Alamos National Laboratory; Sandin, Henrik [Los Alamos National Laboratory; Urbaitis, Algis [Los Alamos National Laboratory

    2010-01-01

    Nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) methods are widely used in medicine, chemistry and industry. Over the past several years there has been increasing interest in performing NMR and MRI in the ultra-low field (ULF) regime, with measurement field strengths of 10-100 microTesla and pre-polarization fields of 30-50 mTesla. The real-time signal-to-noise ratio for such measurements is about 100. Our group at LANL has built and demonstrated the performance of SQUID-based ULF NMR/MRI instrumentation for classification of materials and detection of liquid explosives via their relaxation properties measured at ULF, using T{sub 1}, and T{sub 2}, and T{sub 1} frequency dispersion. We are also beginning to investigate the performance of induction coils as sensors. Here we present recent progress on the applications of ULF MR to the detection of liquid explosives, in imaging and relaxometry.

  6. Remote sensing detection of droughts in Amazonian forest canopies.

    Science.gov (United States)

    Anderson, Liana O; Malhi, Yadvinder; Aragão, Luiz E O C; Ladle, Richard; Arai, Egidio; Barbier, Nicolas; Phillips, Oliver

    2010-08-01

    *Remote sensing data are a key tool to assess large forested areas, where limitations such as accessibility and lack of field measurements are prevalent. Here, we have analysed datasets from moderate resolution imaging spectroradiometer (MODIS) satellite measurements and field data to assess the impacts of the 2005 drought in Amazonia. *We combined vegetation indices (VI) and climatological variables to evaluate the spatiotemporal patterns associated with the 2005 drought, and explore the relationships between remotely-sensed indices and forest inventory data on tree mortality. *There were differences in results based on c4 and c5 MODIS products. C5 VI showed no spatial relationship with rainfall or aerosol optical depth; however, distinct regions responded significantly to the increased radiation in 2005. The increase in the Enhanced VI (EVI) during 2005 showed a significant positive relationship (P NDWI) exhibited a significant negative relationship (P < 0.09) with tree mortality. *Previous studies have suggested that the increase in EVI during the 2005 drought was associated with a positive response of forest photosynthesis to changes in the radiation income. We discuss the evidence that this increase could be related to structural changes in the canopy. PMID:20659255

  7. MRI for the detection of anorectal fistulas; MRT in der Diagnostik anorektaler Fisteln

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, A.O.; Baumann, T.; Langer, M. [Abt. Roentgendiagnostik, Universitaetsklinikum Freiburg (Germany)

    2006-11-15

    MRI is accepted as one of the major diagnostic tools for the detection of anorectal fistulas and abscesses. Noninvasiveness and high accuracy are advantageous hallmarks of this technique. In general, the purpose of imaging anal fistulas is to reduce the risk of recurrence, incontinence and non-healing. To achieve these goals, the applied method must provide the proctologist with detailed information. In this context, MRI acts as a guide for surgeons to accurately plan fistula operations. Another aspect is the follow-up of conservatively treated patients with fistulizing Crohn's disease. In 2000, subtraction MR fistulography was introduced as new imaging technique. This review provides an overview of the entire spectrum of diagnostic modalities for anorectal fistulas with emphasis on subtraction MR fistulography. (orig.)

  8. Haemorrhage in intracerebral arteriovenous malformations: detection with MRI and comparison with clinical history

    International Nuclear Information System (INIS)

    Fifty-one patients with 59 angiographically proven cerebral arteriovenous malformations (AVMs) were examined by high-field MRI to detect blood breakdown products. Results were correlated with the history of intracranial bleeding. Evidence of previous episodes of haemorrhage was seen in 10 of 12 patients (83.3%) with verified bleeding, 4 of 9 patients (44.4%) with symptoms which could suggest bleeding and in 6 of 30 patients (20%) with negative histories. Because of the known rebleeding rate and the increased risk of associated complications, identification of the subgroup who had had haemorrhage and should therefore be considered for surgery may be beneficial. MRI can make a contribution to management by demonstrating prior haemorrhage in patients with an inadequate clinical history. (orig.)

  9. Haemorrhage in intracerebral arteriovenous malformations: detection with MRI and comparison with clinical history

    Energy Technology Data Exchange (ETDEWEB)

    Prayer, L. (Dept. of Radiology, and MR Inst., Univ. of Vienna (Austria)); Wimberger, D (Dept. of Radiology, and MR Inst., Univ. of Vienna (Austria) Dept. of Neurology, Univ. of Vienna (Austria)); Stiglbauer, R. (Dept. of Radiology, and MR Inst., Univ. of Vienna (Austria)); Kramer, J. (Dept. of Radiology, and MR Inst., Univ. of Vienna (Austria)); Richling, B. (Dept. of Neurosurgery, Univ. of Vienna (Austria)); Bavinzski, G. (Dept. of Neurosurgery, Univ. of Vienna (Austria)); Czech, T. (Dept. of Neurosurgery, Univ. of Vienna (Austria)); Imhof, H. (Dept. of Radiology, and MR Inst., Univ. of Vienna (Austria))

    1993-01-01

    Fifty-one patients with 59 angiographically proven cerebral arteriovenous malformations (AVMs) were examined by high-field MRI to detect blood breakdown products. Results were correlated with the history of intracranial bleeding. Evidence of previous episodes of haemorrhage was seen in 10 of 12 patients (83.3%) with verified bleeding, 4 of 9 patients (44.4%) with symptoms which could suggest bleeding and in 6 of 30 patients (20%) with negative histories. Because of the known rebleeding rate and the increased risk of associated complications, identification of the subgroup who had had haemorrhage and should therefore be considered for surgery may be beneficial. MRI can make a contribution to management by demonstrating prior haemorrhage in patients with an inadequate clinical history. (orig.)

  10. Comparison of delayed enhanced cine MRI, single photon emission computed tomography and echocardiography for the detection of viable myocardium

    International Nuclear Information System (INIS)

    Objective: To evaluate the accuracy of delayed enhanced cardiac MRI(DE-MRI), nitrate stress 99Tcm-MIBI imaging (N-SPECT) and low-dose dobutamine stress echocardiography (LDDSE) for the detection of viable myocardium. Methods: Cardiac rest cine MRI(cine-MRI), DE-URI, N-SPECT and LDDSE were performed in 32 patients within one week after onset of acute myocardial infarction and undertaking percutaneous coronary intervention (PCI) thereafter. Second cine-MRI was performed 6- 11 months after PCI. A 16-segment model was adopted for the image analysis. Wall motion improvement after PCI was considered as a myocardial viability. The sensitivity, specificity and accuracy of three methods for the detection of viable segments were compared dy t and ?2 test. Results: The sensitivity, specificity and accuracy of DE-MRI were 76.7% (79/103), 83.8% (88/105)and 80.3% (167/208), respectively. The sensitivity, specificity and accuracy of N-SPECT were 75.9% (82/108), 65.2% (60/92) and 71.0% (142/200), respectively. The specificity and accuracy of N-SPECT were significantly lower than that of DE- MRI(P<0.01). The sensitivity, specificity and accuracy of LDDSE were 70.1% (47/67), 70.4% (50/71) and 70. 3% (97/138), respectively. The sensitivity of LDDSE was comparable to that of DE-MRI and the specificity and accuracy of LDDSE were significantly lower than that of DE-MRI (P<0.05). Conclusion: DE-MRI with high specificity and accuracy, potentially, is a valuable imaging method for the detection of viable myocardium. (authors)

  11. Presumptive subarticular stress reactions of the knee: MRI detection and association with meniscal tear patterns

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Lawrence [Diagnostic Radiology Department, National Institutes of Health, Building 10, Room 1C640, 10 Center Drive, MSC 1182, MD 20892-1182, Bethesda (United States); Stanczak, Jeffrey [Fairfax Radiological Consultants, PC, 2722 Merrilee Drive, Suite 230, VA 22031, Fairfax (United States); Boutin, Robert D. [MedTel International, 1430 Spring Hill Road, State 500, VA 22102, Mclean (United States)

    2004-05-01

    MRI detects subchondral marrow findings in painful knees which bear resemblance to spontaneous osteonecrosis of the knee (SONK). Gathering evidence suggests that the primary or predominant pathogenesis of these lesions is physical stress. This study analyzes the patient characteristics and meniscal pathology associated with these lesions - herein referred to as ''presumptive subarticular stress related'' (PSSR) lesions. All patients were scanned using a standardized imaging protocol. The criterion for a PSSR lesion was a subchondral marrow edema pattern encompassing a more focal, low-signal zone adjacent to or contiguous with the subchondral cortex. Patients were identified using an electronic database search of cases reported by one experienced musculoskeletal radiologist. Twenty-five PSSR lesions were identified among 1,948 MRI evaluations of the knee. Twenty-one PSSR lesions occurred in the medial compartment, and four occurred in the lateral compartment. There was no sex predilection. Patients with PSSR lesions were older than other patients undergoing MRI evaluation (mean 66 years versus 52 years, P<0.001). Meniscal tears occurred more commonly in cases with PSSR lesions than in the group as a whole (76% versus 45%, P<0.001). Radial and posterior root tears were more common in knees with PSSR lesions than in other knees with meniscal tears (53% versus 26%, P<0.01). PSSR lesions are associated with meniscal tears and, more specifically, with meniscal tear patterns that dramatically increase contact forces across the knee joint. This observation supports the hypothesis that mechanical stress is important in the pathogenesis of these subarticular lesions that are detected by MRI. (orig.)

  12. Presumptive subarticular stress reactions of the knee: MRI detection and association with meniscal tear patterns

    International Nuclear Information System (INIS)

    MRI detects subchondral marrow findings in painful knees which bear resemblance to spontaneous osteonecrosis of the knee (SONK). Gathering evidence suggests that the primary or predominant pathogenesis of these lesions is physical stress. This study analyzes the patient characteristics and meniscal pathology associated with these lesions - herein referred to as ''presumptive subarticular stress related'' (PSSR) lesions. All patients were scanned using a standardized imaging protocol. The criterion for a PSSR lesion was a subchondral marrow edema pattern encompassing a more focal, low-signal zone adjacent to or contiguous with the subchondral cortex. Patients were identified using an electronic database search of cases reported by one experienced musculoskeletal radiologist. Twenty-five PSSR lesions were identified among 1,948 MRI evaluations of the knee. Twenty-one PSSR lesions occurred in the medial compartment, and four occurred in the lateral compartment. There was no sex predilection. Patients with PSSR lesions were older than other patients undergoing MRI evaluation (mean 66 years versus 52 years, P<0.001). Meniscal tears occurred more commonly in cases with PSSR lesions than in the group as a whole (76% versus 45%, P<0.001). Radial and posterior root tears were more common in knees with PSSR lesions than in other knees with meniscal tears (53% versus 26%, P<0.01). PSSR lesions are associated with meniscal tears and, more specifically, with meniscal tear patterns that dramatically increase contact forces across the knee joint. This observation supports the hypothesis that mechanical stress is important in the pathogenesis of these subarticular lesions that are detected by MRI. (orig.)

  13. Detection of emission sources using passive-remote Fourier transform infrared spectroscopy

    International Nuclear Information System (INIS)

    The detection and identification of toxic chemicals released in the environment is important for public safety. Passive-remote Fourier transform infrared (FTIR) spectrometers can be used to detect these releases. Their primary advantages are their small size and ease of setup and use. Open-path FTIR spectrometers are used to detect concentrations of pollutants from a fixed frame of reference. These instruments detect plumes, but they are too large and difficult to aim to be used to track a plume to its source. Passive remote FTIR spectrometers contain an interferometer, optics, and a detector. They can be used on tripods and in some cases can be hand-held. A telescope can be added to most units. We will discuss the capability of passive-remote FTIR spectrometers to detect the origin of plumes. Low concentration plumes were released using a custom-constructed vaporizer. These plumes were detected with different spectrometers from different distances. Passive-remote spectrometers were able to detect small 10 cm on a side chemical releases at concentration-pathlengths at the low parts per million-meter (ppm-m) level

  14. Integrated data processing of remotely sensed and vector data for building change detection

    Science.gov (United States)

    Sofina, N.; Ehlers, M.; Michel, U.

    2012-10-01

    In recent years natural disasters have had an increasing impact leading to tremendous economic and human losses. Remote sensing technologies are being used more often for rapid detection and visualization of changes in the affected areas, providing essential information for damage assessment, planning and coordination of recovery activities. This study presents a GIS-based approach for the detection of damaged buildings. The methodology is based on the integrated analysis of vector data containing information about the original urban layout and remotely sensed images obtained after a catastrophic event. For the classification of building integrity a new `Detected Part of Contour' (DPC) feature was developed. The DPC feature defines a part of the building contour that can be detected in the related remotely sensed image. It reaches maximum value (100%) if the investigated building contour is intact. Next, several features based on the analysis of textural information of the remotely sensed image are considered. Finally, a binary classification of building conditions concludes the change detection analysis. The proposed method was applied to the 2010 earthquake in Qinghai (China). The results indicate that a GIS-based analysis can markedly improve the accuracy of change detection analysis. The proposed methodology has been developed solely within the Open Source Software environment (GRASS GIS, Python, Orange). The employment of Open Source Software provides the way for an innovative, flexible and costeffective implementation of change detection operations.

  15. Diagnostic accuracy of portal-phase CT and MRI with mangafodipir trisodium in detecting liver metastases from colorectal carcinoma

    International Nuclear Information System (INIS)

    AIM: To compare the diagnostic accuracy of single section spiral computed tomography (CT) and magnetic resonance imaging (MRI) with tissue-specific contrast agent mangafodipir trisodium (MnDPDP) in the detection of colorectal liver metastases. MATERIAL AND METHODS: One hundred and twenty-five consecutive patients undergoing surgery for primary and/or metastatic disease were evaluated using CT (5 mm collimation and reconstruction interval, pitch 2), two-dimensional fast spoiled gradient echo (2D FSPGR) T1 and single shot fast-spin echo (SSFSE) T2 weighted breath-hold MRI sequences, performed before and after intravenous administration of MnDPDP. The reference standards were intraoperative ultrasound and histology. RESULTS: The per-patient accuracy of CT was 72.8 versus 78.4% for unenhanced MRI (p=0.071) and 82.4% for MnDPDP-enhanced MRI (p=0.005). MnDPDP-enhanced MRI appeared to be more accurate than unenhanced MRI but this was not significant (p=0.059). The sensitivity of CT was 48.4% versus 58.1% for unenhanced MRI (p=0.083) and 66.1% for MnDPDP-enhanced MRI (p=0.004). The difference in specificity between procedures was not significant. The per-lesion sensitivity was 71.7, 74.9 and 82.7% for CT, unenhanced MRI, and MnDPDP-enhanced MRI, respectively; the positive predictive value of the procedures was respectively 84.0, 96.0 and 95.8%. MnDPDP-enhanced MRI provided a high level diagnostic confidence in 92.5% of the cases versus 82.5% for both unenhanced MRI and CT. The kappa value for inter-observer variability was >0.75 for all procedures. CONCLUSIONS: The diagnostic accuracy and sensitivity of MnDPDP-enhanced MRI is significantly higher than single section spiral CT in the detection of colorectal cancer liver metastases; no significant difference in diagnostic accuracy was observed between unenhanced MRI and MnDPDP-enhanced MRI

  16. Remote detection of gases by gas correlation spectroradiometry

    Science.gov (United States)

    Margolis, J. S.; Mccleese, B. J.; Martonchik, J. V.

    1983-01-01

    The present investigation is concerned with the application of a pressure modulated radiometer (PMR) to the remote sensing of trace amounts of gases in the atmospheres as well as to the direct measurement of upper atmospheric winds. The PMR operates as a gas correlation spectrometer. Compared to conventional gas correlation parameters, it has some advantages which are related to greater versatility and the employment of a simpler method for maintaining electrical/optical balance. The PMR has a high sensitivity in connection with its essentially very high effective resolution. It represents a passive system and emits no radiation. A PMR is flown on Nimbus 6 which was launched in 1975. The instrument has also been used on the Nimbus 7 satellite and the Tiros N satellite.

  17. Colorimetric detection of hazardous gases using a remotely operated capturing and processing system.

    Science.gov (United States)

    Montes-Robles, Roberto; Moragues, María Esperanza; Vivancos, José-Luis; Ibáñez, Javier; Fraile, Rubén; Martínez-Máñez, Ramón; García-Breijo, Eduardo

    2015-11-01

    This paper presents an electronic system for the automatic detection of hazardous gases. The proposed system implements colorimetric sensing algorithms, thus providing a low-cost solution to the problem of gas sensing. It is remotely operated and it performs the tasks of image capturing and processing, hence obtaining colour measurements in RGB (Red-Green-Blue) space that are subsequently sent to a remote operator via the internet. A prototype of the system has been built to test its performance. Specifically, experiments have been carried out aimed at the detection of CO, CO2, NO, NO2, SO2 and formaldehyde at diverse concentrations by using a chromogenic array composed by 13 active and 2 inert compounds. Statistical analyses of the results reveal a good performance of the electronic system and the feasibility of remote hazardous gas detection using colorimetric sensor arrays. PMID:26434416

  18. Remote Infrasound Monitoring of Mount Etna: Observed and Predicted Network Detection Capability

    OpenAIRE

    Dorianne Tailpied; Alexis Le Pichon; Emanuele Marchetti; Maurizio Ripepe; Mohamed Kallel; Lars Ceranna; Nicolas Brachet

    2013-01-01

    Volcanic eruptions are valuable calibrating sources of infrasonic waves worldwide detected by the International Moni-toring System (IMS) of the Comprehensive Nuclear Test-Ban-Treaty Organization (CTBTO) and other experimental stations. In this study, we assess the detection capability of the European infrasound network to remotely detect the eruptive activity of Mount Etna. This well-instrumented volcano offers unique opportunity to validate attenuation mod-elsusing multi-year near- and far-f...

  19. Remote laser detection of natural gas leakages from pipelines

    International Nuclear Information System (INIS)

    A differential absorption lidar based on a tunable TEA CO2 laser emitting at 42 lines of the 'hot' 0111 - 1110 band in the range from 10.9 to 11.4 ?m is developed for detecting natural gas leakages from oil pipelines by measuring the ethane content in the atmosphere. The ethane detection sensitivity is 0.9 ppm km. The presence of methane does not distort the measurement results. The developed lidar can detect the natural gas leakage from kilometre heights at the flying velocities up to 200 km h-1 and a probe pulse repetition rate of 5 Hz. (laser applications and other topics in quantum electronics)

  20. Detection and quantification of regional cortical gray matter damage in multiple sclerosis utilizing gradient echo MRI

    Directory of Open Access Journals (Sweden)

    Jie Wen

    2015-01-01

    Full Text Available Cortical gray matter (GM damage is now widely recognized in multiple sclerosis (MS. The standard MRI does not reliably detect cortical GM lesions, although cortical volume loss can be measured. In this study, we demonstrate that the gradient echo MRI can reliably and quantitatively assess cortical GM damage in MS patients using standard clinical scanners. High resolution multi-gradient echo MRI was used for regional mapping of tissue-specific MRI signal transverse relaxation rate values (R2* in 10 each relapsing–remitting, primary-progressive and secondary-progressive MS subjects. A voxel spread function method was used to correct artifacts induced by background field gradients. R2* values from healthy controls (HCs of varying ages were obtained to establish baseline data and calculate ?R2* values – age-adjusted differences between MS patients and HC. Thickness of cortical regions was also measured in all subjects. In cortical regions, ?R2* values of MS patients were also adjusted for changes in cortical thickness. Symbol digit modalities (SDMT and paced auditory serial addition (PASAT neurocognitive tests, as well as Expanded Disability Status Score, 25-foot timed walk and nine-hole peg test results were also obtained on all MS subjects. We found that ?R2* values were lower in multiple cortical GM and normal appearing white matter (NAWM regions in MS compared with HC. ?R2* values of global cortical GM and several specific cortical regions showed significant (p < 0.05 correlations with SDMT and PASAT scores, and showed better correlations than volumetric measures of the same regions. Neurological tests not focused on cognition (Expanded Disability Status Score, 25-foot timed walk and nine-hole peg tests showed no correlation with cortical GM ?R2* values. The technique presented here is robust and reproducible. It requires less than 10 min and can be implemented on any MRI scanner. Our results show that quantitative tissue-specific R2* values can serve as biomarkers of tissue injury due to MS in the brain, including the cerebral cortex, an area that has been difficult to evaluate using standard MRI.

  1. Columbia - Invasive Species Detection from Remote and Groundbased Mapping

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Columbia NWR has a number of invasive plants that have gone untreated due to lack of staff for detection and mapping. Volunteers can be used to map some areas where...

  2. Mobile Passive Optical Imager for Remote Gas Detection Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Tunable filters based on electro-optic effect have shown great potential in detecting gas concentration through obtaining its absorption spectrum. In filter-based...

  3. Activation detection in functional MRI using subspace modeling and maximum likelihood estimation.

    Science.gov (United States)

    Ardekani, B A; Kershaw, J; Kashikura, K; Kanno, I

    1999-02-01

    A statistical method for detecting activated pixels in functional MRI (fMIRI) data is presented. In this method, the fMRI time series measured at each pixel is modeled as the sum of a response signal which arises due to the experimentally controlled activation-baseline pattern, a nuisance component representing effects of no interest, and Gaussian white noise. For periodic activation-baseline patterns, the response signal is modeled by a truncated Fourier series with a known fundamental frequency but unknown Fourier coefficients. The nuisance subspace is assumed to be unknown. A maximum likelihood estimate is derived for the component of the nuisance subspace which is orthogonal to the response signal subspace. An estimate for the order of the nuisance subspace is obtained from an information theoretic criterion. A statistical test is derived and shown to be the uniformly most powerful (UMP) test invariant to a group of transformations which are natural to the hypothesis testing problem. The maximal invariant statistic used in this test has an F distribution. The theoretical F distribution under the null hypothesis strongly concurred with the experimental frequency distribution obtained by performing null experiments in which the subjects did not perform any activation task. Application of the theory to motor activation and visual stimulation fMRI studies is presented. PMID:10232667

  4. Detection of bone marrow and extramedullary involvement in patients with non-Hodgkin's lymphoma by whole-body MRI: comparison with bone and 67Ga scintigraphies.

    Science.gov (United States)

    Iizuka-Mikami, Masami; Nagai, Kiyohisa; Yoshida, Koji; Sugihara, Takashi; Suetsugu, Yoshimasa; Mikami, Makoto; Tamada, Tsutomu; Imai, Shigeki; Kajihara, Yasumasa; Fukunaga, Masao

    2004-06-01

    The aim of this study was to evaluate the diagnostic potential of whole-body MRI (WB-MRI) for the detection of bone marrow and extramedullary involvement in patients with non-Hodgkin's lymphoma. WB-MRI, which was performed on 34 patients, consisted of the recording of T1-weighted spin-echo images and a fast STIR sequence covering the entire skeleton. The WB-MRI findings for bone marrow and extramedullary involvement were compared with those from (67)Ga and bone scintigraphies and bone marrow biopsy results. Two MRI specialists reviewed the WB-MRI results and two expert radiologists in the field of nuclear medicine reviewed the bone and (67)Ga scintigraphy findings. Bone marrow and extramedullary involvement of non-Hodgkin's lymphoma were confirmed by follow-up radiographs and CT and/or a histological biopsy. The detection rate of WB-MRI was high. More bone marrow involvement was detected by biopsy, and more lesions were detected by scintigraphies. In total, 89 lesions were detected by WB-MRI, whereas 15 were found by biopsy, 5 by (67)Ga scintigraphy, and 14 by bone scintigraphy. WB-MRI could also detect more extramedullary lesions than (67)Ga scintigraphy; i.e., 72 lesions were detected by WB-MRI, whereas 54 were discovered by (67)Ga scintigraphy. WB-MRI is useful for evaluating the involvement of bone marrow and extramedullary lesions throughout the skeleton in patients with non-Hodgkin's lymphoma. PMID:14986048

  5. Detection of bone marrow and extramedullary involvement in patients with non-Hodgkin's lymphoma by whole-body MRI: comparison with bone and 67Ga scintigraphies

    International Nuclear Information System (INIS)

    The aim of this study was to evaluate the diagnostic potential of whole-body MRI (WB-MRI) for the detection of bone marrow and extramedullary involvement in patients with non-Hodgkin's lymphoma. WB-MRI, which was performed on 34 patients, consisted of the recording of T1-weighted spin-echo images and a fast STIR sequence covering the entire skeleton. The WB-MRI findings for bone marrow and extramedullary involvement were compared with those from 67Ga and bone scintigraphies and bone marrow biopsy results. Two MRI specialists reviewed the WB-MRI results and two expert radiologists in the field of nuclear medicine reviewed the bone and 67Ga scintigraphy findings. Bone marrow and extramedullary involvement of non-Hodgkin's lymphoma were confirmed by follow-up radiographs and CT and/or a histological biopsy. The detection rate of WB-MRI was high. More bone marrow involvement was detected by biopsy, and more lesions were detected by scintigraphies. In total, 89 lesions were detected by WB-MRI, whereas 15 were found by biopsy, 5 by 67Ga scintigraphy, and 14 by bone scintigraphy. WB-MRI could also detect more extramedullary lesions than 67Ga scintigraphy; i.e., 72 lesions were detected by WB-MRI, whereas 54 were discovered by 67Ga scintigraphy. WB-MRI is useful for evaluating the involvement of bone marrow and extramedullary lesions throughout the skeleton in patients with non-Hodgkin's lymphoma. (orig.)

  6. Substitute or complement? Defining the relative place of EEG and fMRI in the detection of voluntary brain reactions.

    Science.gov (United States)

    Gabriel, D; Henriques, J; Comte, A; Grigoryeva, L; Ortega, J-P; Cretin, E; Brunotte, G; Haffen, E; Moulin, T; Aubry, R; Pazart, L

    2015-04-01

    To improve the assessment of awareness in patients with disorders of consciousness, recent protocols using functional Magnetic Resonance Imaging (fMRI) have been developed, and led some specialized coma centers to use this method on a routine basis. Recently, promising results have also been observed with electroencephalography (EEG), a less expensive and widely available technique. However, since the spatiotemporal nature of the recorded signal differs between both EEG and fMRI, the question of whether one method could substitute or should complement the other method is a matter of debate. In this study, we compared the neural processes of two well-known EEG and fMRI mental imagery protocols to define the relative place of each method in the assessment of awareness. A group of 20 healthy volunteers performed both EEG and fMRI command-following and communication tasks. Distinct command following was found with both EEG and fMRI for five subjects, only with fMRI for 12 subjects, and only with EEG for one subject. In the communication task, neither EEG nor fMRI alone gave satisfactory results and no reliable communication could be established in approximately 1/3rd of the participants. If fMRI showed the best performance to detect volitional reactions in mental imagery tasks, our results provide evidence that the use of EEG must not be underestimated since a better detection was found with this method for at least one subject. More than being used as a substitute, EEG should complement fMRI to improve the detection of sign of awareness, and to reduce the risks of misjudgments. PMID:25644421

  7. A novel Hessian based algorithm for rat kidney glomerulus detection in 3D MRI

    Science.gov (United States)

    Zhang, Min; Wu, Teresa; Bennett, Kevin M.

    2015-03-01

    The glomeruli of the kidney perform the key role of blood filtration and the number of glomeruli in a kidney is correlated with susceptibility to chronic kidney disease and chronic cardiovascular disease. This motivates the development of new technology using magnetic resonance imaging (MRI) to measure the number of glomeruli and nephrons in vivo. However, there is currently a lack of computationally efficient techniques to perform fast, reliable and accurate counts of glomeruli in MR images due to the issues inherent in MRI, such as acquisition noise, partial volume effects (the mixture of several tissue signals in a voxel) and bias field (spatial intensity inhomogeneity). Such challenges are particularly severe because the glomeruli are very small, (in our case, a MRI image is ~16 million voxels, each glomerulus is in the size of 8~20 voxels), and the number of glomeruli is very large. To address this, we have developed an efficient Hessian based Difference of Gaussians (HDoG) detector to identify the glomeruli on 3D rat MR images. The image is first smoothed via DoG followed by the Hessian process to pre-segment and delineate the boundary of the glomerulus candidates. This then provides a basis to extract regional features used in an unsupervised clustering algorithm, completing segmentation by removing the false identifications occurred in the pre-segmentation. The experimental results show that Hessian based DoG has the potential to automatically detect glomeruli,from MRI in 3D, enabling new measurements of renal microstructure and pathology in preclinical and clinical studies.

  8. Hepatic MRI with SPIO: detection and characterization of focal liver lesions

    International Nuclear Information System (INIS)

    A variety of parenterally administered iron oxides have been developed for contrast-enhanced MRI of the liver. Two different classes of iron oxides are currently clinically approved or in phase 3 trials: superparamagnetic iron oxides (SPIO) with a high R2/R1 relaxivity ratio and short blood half-life (AMI-25 and SH U 555 A), and ultrasmall paramagnetic iron oxides (USPIO) with a lower R2/R1 relaxivity ratio and longer blood half-life (AMI-227). All iron oxides significantly increase tumor-to-liver contrast and allow detection of more lesions than unenhanced MRI on T2-weighted images at a field strength of 0.2-1.5 T. Malignant lesions without phagocytic cells exhibit constant signal on T2-weighted accumulation phase images with all three iron oxides. All iron oxides cause a signal decrease of benign lesions with either phagocytic cells or a significant blood pool on T2-weighted accumulation phase images. The signal decrease of benign lesions is proportional to the Kupffer cell activity or tumor vascularity and is useful for lesion characterization. Another enhancement feature for the differentiation of benign from malignant lesions is ring enhancement of malignant lesions (metastases) on T1-weighted enhanced images either during the perfusion phase with SH U 555 A or during the accumulation phase with AMI-227, which is attributed to the blood pool effects of the compounds. Differentiation of lesions and vessels is easier on enhanced images with angiographic effects than on unenhanced images. Iron oxides improve the quality of two-dimensional MR angiography techniques of the portal venous system by decreasing background signal (liver tissue with all iron oxides) and increasing intravascular signal (AMI-227). The use of iron oxides for hepatic MRI provides an alternative to the existing multistep diagnosis with CT, CT portography, MRI and biopsy. (orig.)

  9. Contrast-enhanced spectral mammography versus MRI: Initial results in the detection of breast cancer and assessment of tumour size

    Energy Technology Data Exchange (ETDEWEB)

    Fallenberg, E.M.; Renz, D.M. [Charite - Universitaetsmedizin Berlin, Clinic of Radiology, Berlin (Germany); Dromain, C. [Institut Gustave Roussy, Department of Radiology, Villejuif cedex (France); Diekmann, F. [St. Joseph-Stift Bremen, Department of Medical Imaging, Bremen (Germany); Engelken, F.; Krohn, M.; Singh, J.M.; Bick, U. [Charite - Universitaetsmedizin Berlin, Department of Radiology, Berlin (Germany); Ingold-Heppner, B. [Charite - Universitaetsmedizin Berlin, Institute of Pathology, Berlin (Germany); Winzer, K.J. [Charite - Universitaetsmedizin Berlin, Breast Center, Department of Gynecology, Berlin (Germany)

    2014-01-15

    To compare mammography (MG), contrast-enhanced spectral mammography (CESM), and magnetic resonance imaging (MRI) in the detection and size estimation of histologically proven breast cancers using postoperative histology as the gold standard. After ethical approval, 80 women with newly diagnosed breast cancer underwent MG, CESM, and MRI examinations. CESM was reviewed by an independent experienced radiologist, and the maximum dimension of suspicious lesions was measured. For MG and MRI, routine clinical reports of breast specialists, with judgment based on the BI-RADS lexicon, were used. Results of each imaging technique were correlated to define the index cancer. Fifty-nine cases could be compared to postoperative histology for size estimation. Breast cancer was visible in 66/80 MG, 80/80 CESM, and 77/79 MRI examinations. Average lesion largest dimension was 27.31 mm (SD 22.18) in MG, 31.62 mm (SD 24.41) in CESM, and 27.72 mm (SD 21.51) in MRI versus 32.51 mm (SD 29.03) in postoperative histology. No significant difference was found between lesion size measurement on MRI and CESM compared with histopathology. Our initial results show a better sensitivity of CESM and MRI in breast cancer detection than MG and a good correlation with postoperative histology in size assessment. (orig.)

  10. Contrast-enhanced spectral mammography versus MRI: Initial results in the detection of breast cancer and assessment of tumour size

    International Nuclear Information System (INIS)

    To compare mammography (MG), contrast-enhanced spectral mammography (CESM), and magnetic resonance imaging (MRI) in the detection and size estimation of histologically proven breast cancers using postoperative histology as the gold standard. After ethical approval, 80 women with newly diagnosed breast cancer underwent MG, CESM, and MRI examinations. CESM was reviewed by an independent experienced radiologist, and the maximum dimension of suspicious lesions was measured. For MG and MRI, routine clinical reports of breast specialists, with judgment based on the BI-RADS lexicon, were used. Results of each imaging technique were correlated to define the index cancer. Fifty-nine cases could be compared to postoperative histology for size estimation. Breast cancer was visible in 66/80 MG, 80/80 CESM, and 77/79 MRI examinations. Average lesion largest dimension was 27.31 mm (SD 22.18) in MG, 31.62 mm (SD 24.41) in CESM, and 27.72 mm (SD 21.51) in MRI versus 32.51 mm (SD 29.03) in postoperative histology. No significant difference was found between lesion size measurement on MRI and CESM compared with histopathology. Our initial results show a better sensitivity of CESM and MRI in breast cancer detection than MG and a good correlation with postoperative histology in size assessment. (orig.)

  11. CLASSIFICATION OF LAND USE LAND COVER CHANGE DETECTION USING REMOTELY SENSED DATA

    Directory of Open Access Journals (Sweden)

    Y.Babykalpana

    2011-04-01

    Full Text Available Image classification is perhaps the most important part of digital image analysis. With supervised classification, the information classes of interest like land cover type image. These are called “training sites”. The image processing software system is then used to develop a statistical characterization of the reflectance foreach information class. This stage is often called “ Signature analysis” .Unsupervised classification is a method which examines a large number of unknown pixels and divides into a number of classes based on natural groupings present in the image values. Unsupervised classification is becoming increasingly popular in agencies involved in long term GIS database maintenance. The reason is thatthere are now systems that use clustering procedures that are extremely fast and require little in the nature of operational parameters. Thus it is becoming possible to train GIS analysis with only a general familiarity with remote sensing to undertake classification that meet typical map accuracy standards. With suitable ground truth accuracy assessment procedures , this tool can provide a remarkably rapid means of producing quality land cover data on a continuing basis.The profusion information of the earth surface offered by the high resolution satellite images for remote sensing applications. Using change detection methodologies to extract the target changes in the areas from high resolution images and rapidly updates geodatabase information processing.However, the traditional method of change detection are not suitable for high resolution remote sensing images. To overcome the limitations of traditional pixel-level change detection of high resolution remote sensing images, based on georeferencing and analysis method, this paper presents a clean way of multi-scaleamalgamation for the high resolution remote sensing images change detection. Experiment shows that this method has a stronger advantage than the traditional pixel-level method of high resolution remote sensing image change detection.

  12. Remote sensing network to detect and identify organic vapours

    Science.gov (United States)

    Elosua, Cesar; Perez-Herrera, Rosa Ana; Lopez-Amo, Manuel; Bariain, Candido; Luquin, Asuncion; Laguna, Mariano

    2009-10-01

    In this work, a novel CWDM (Coarse Wavelength Division Multiplexing) network that multiplexes intensity modulated optical fibre sensors is presented. These transducers are based on a sensing material that suffers reversible changes in its optical properties in presence of organic vapours. This compound is fixed onto cleaved ended single mode optical fibres pigtails using Electrostatic Self-Assembly method. As their response depends on intensity changes, a referencing signal is simultaneously generated to eliminate the effect of optical source power fluctuations. Thus, a parallel array of phaseshifted fibre Bragg gratings (PS-FBGs) is included to obtain the referencing signal. Looking forward to remote sensing applications, an Erbium doped fibre amplifier (EDFA) is included in the header of the network to reach up to 4 km of distance. Four new sensors have been multiplexed and exposed to saturated atmospheres of methanol and ethanol individually, showing different response and recovery times in each case. Finally, we checked that our sensors were able to distinguish between pure and kerosene polluted water probes in terms of response and recovery times as well.

  13. Remote detection of degradation of fire-resistant fluid lubricants

    International Nuclear Information System (INIS)

    The original work under EPRI contract RP893-1 identified a phosphate ester lubricant as having the necessary lubricating and fire properties for use as a fire resistant lubricant in reactor coolant pump motors. However, these lubricants are subject to self-catalyzing degradation. The purpose of this added effort was to identify, review, and rank existing and innovative methods for remotely monitoring the lubricant degradation. Several possible techniques were identified and preliminary experimental evaluation was performed on three of them. Of the techniques considered, measurement of fluid resistivity or conductivity shows the most promise. The major advantages of conductivity measurement are that it is based on simple, mature hardware, thus providing high reliability of the instrumentation itself, and that there is substantial evidence that it will not give a false satisfactory indication as the fluid starts to degrade. The major disadvantages are that it is not a direct measure of fluid acid number, the pertinent degradation parameter, and that it is also affected by fluid contaminants, such as water, which may accelerate fluid degradation but are not directly related to the immediate condition of the fluid

  14. Novel membrane-permeable contrast agent for brain tumor detection by MRI.

    Science.gov (United States)

    Kumar, Mohanraja; Medarova, Zdravka; Pantazopoulos, Pamela; Dai, Guangping; Moore, Anna

    2010-03-01

    One of the key challenges hindering the clinical intervention against brain cancer is defined by the inability to detect brain tumors at an early enough stage to permit effective therapy. Furthermore, the rapid growth and severe lethality of this form of cancer predicate the vital importance of monitoring the development of the pathology and its outcome after therapeutic intervention. With this in mind, we designed a novel membrane-permeant contrast agent, MN-MPAP-Cy5.5, which consists of a superparamagnetic iron oxide core, for MRI conjugated to myristoylated polyarginine peptides, as a membrane translocation module and labeled with the near-infrared dye Cy5.5 for correlative microscopy. This probe showed a remarkable uptake by U-87 human glioma cells in vitro and localized and delineated stereotactically injected tumor in vivo by MRI. Our findings suggest that the agent mediates its effects by translocation of the magnetic nanoparticles label across the leaky tumor vasculature, followed by enhanced accumulation in tumor cells. The noninvasive detection of brain tumors when they are still small represents a formidable challenge from an imaging standpoint. Our study describes an improved strategy to detect brain lesions by utilizing a contrast agent with membrane translocation properties. PMID:20146231

  15. Dynamic connectivity detection: an algorithm for determining functional connectivity change points in fMRI data

    Science.gov (United States)

    Xu, Yuting; Lindquist, Martin A.

    2015-01-01

    Recently there has been an increased interest in using fMRI data to study the dynamic nature of brain connectivity. In this setting, the activity in a set of regions of interest (ROIs) is often modeled using a multivariate Gaussian distribution, with a mean vector and covariance matrix that are allowed to vary as the experiment progresses, representing changing brain states. In this work, we introduce the Dynamic Connectivity Detection (DCD) algorithm, which is a data-driven technique to detect temporal change points in functional connectivity, and estimate a graph between ROIs for data within each segment defined by the change points. DCD builds upon the framework of the recently developed Dynamic Connectivity Regression (DCR) algorithm, which has proven efficient at detecting changes in connectivity for problems consisting of a small to medium (100). The newly proposed DCD method is faster, requires less user input, and is better able to handle high-dimensional data. It overcomes the shortcomings of DCR by adopting a simplified sparse matrix estimation approach and a different hypothesis testing procedure to determine change points. The application of DCD to simulated data, as well as fMRI data, illustrates the efficacy of the proposed method. PMID:26388711

  16. Model-based automatic detection of the anterior and posterior commissures on MRI scans.

    Science.gov (United States)

    Ardekani, Babak A; Bachman, Alvin H

    2009-07-01

    The projections of the anterior and posterior commissures (AC/PC) on the mid-sagittal plane of the human brain are important landmarks in neuroimaging. They can be used, for example, during MRI scanning for acquiring the imaging sections in a standard orientation. In post-acquisition image processing, these landmarks serve to establish an anatomically-based frame of reference within the brain that can be extremely useful in designing automated image analysis algorithms such as image segmentation and registration methods. This paper presents a fully automatic model-based algorithm for AC/PC detection on MRI scans. The algorithm utilizes information from a number of model images on which the locations of the AC/PC and a reference point (the vertex of the superior pontine sulcus) are known. This information is then used to locate the landmarks on test scans by template matching. The algorithm is designed to be fast, robust, and accurate. The method is flexible in that it can be trained to work on different image contrasts, optimized for different populations, or scanning modes. To assess the effectiveness of this technique, we compared automatically and manually detected landmark locations on 84 T(1)-weighted and 42 T(2)-weighted test scans. Overall, the average Euclidean distance between automatically and manually detected landmarks was 1.1 mm. A software implementation of the algorithm is freely available online at www.nitrc.org/projects/art. PMID:19264138

  17. New development of MRI lung nodule simulator for detecting on pulmonary nodule

    International Nuclear Information System (INIS)

    In an effort to augment the value of MRI in detecting lung nodules, we devised a new lung nodule phantom made of polyvinylalcohol. Besides, a thoracic phantom made of polyvinyl alcohol, solidoils, and artificial bone was prepared to evaluate the environmental effect around the nodule phantom. The p, T1 and T2 values of these simulators were equivalent to those of chest wall tissues. T1 and T2 of these phantoms were calculated by use of a 0.2T resistive magnetic resonance machine. Our findings suggested that T1 and T2 of the lung nodule phantom varies as a function of position. (author)

  18. Detection of electroporation-induced membrane permeabilization states in the brain using diffusion-weighted MRI

    DEFF Research Database (Denmark)

    Mahmood, Faisal; Hansen, Rasmus H; Agerholm-Larsen, Birgit; Gissel, Hanne; Ibsen, Per; Gehl, Julie

    Background. Tissue permeabilization by electroporation (EP) is a promising technique to treat certain cancers. Non-invasive methods for verification of induced permeabilization are important, especially in deep-seated cancers. In this study we evaluated diffusion-weighted magnetic resonance imaging...... (DW-MRI) as a quantitative method for detecting EP-induced membrane permeabilization of brain tissue using a rat brain model. Material and methods. Fifty-four anesthetized Sprague-Dawley male rats were electroporated in the right hemisphere, using different voltage levels to induce no permeabilization...

  19. A Novel GBM Saliency Detection Model Using Multi-Channel MRI

    Science.gov (United States)

    Banerjee, Subhashis; Mitra, Sushmita; Shankar, B. Uma; Hayashi, Yoichi

    2016-01-01

    The automatic computerized detection of regions of interest (ROI) is an important step in the process of medical image processing and analysis. The reasons are many, and include an increasing amount of available medical imaging data, existence of inter-observer and inter-scanner variability, and to improve the accuracy in automatic detection in order to assist doctors in diagnosing faster and on time. A novel algorithm, based on visual saliency, is developed here for the identification of tumor regions from MR images of the brain. The GBM saliency detection model is designed by taking cue from the concept of visual saliency in natural scenes. A visually salient region is typically rare in an image, and contains highly discriminating information, with attention getting immediately focused upon it. Although color is typically considered as the most important feature in a bottom-up saliency detection model, we circumvent this issue in the inherently gray scale MR framework. We develop a novel pseudo-coloring scheme, based on the three MRI sequences, viz. FLAIR, T2 and T1C (contrast enhanced with Gadolinium). A bottom-up strategy, based on a new pseudo-color distance and spatial distance between image patches, is defined for highlighting the salient regions in the image. This multi-channel representation of the image and saliency detection model help in automatically and quickly isolating the tumor region, for subsequent delineation, as is necessary in medical diagnosis. The effectiveness of the proposed model is evaluated on MRI of 80 subjects from the BRATS database in terms of the saliency map values. Using ground truth of the tumor regions for both high- and low- grade gliomas, the results are compared with four highly referred saliency detection models from literature. In all cases the AUC scores from the ROC analysis are found to be more than 0.999 ± 0.001 over different tumor grades, sizes and positions. PMID:26752735

  20. Is MRI better than CT for detecting a vascular component to dementia? A systematic review and meta-analysis.

    OpenAIRE

    Beynon Rebecca; Sterne Jonathan A C; Wilcock Gordon; Likeman Marcus; Harbord Roger M; Astin Margaret; Burke Margaret; Bessell Alysson; Ben-Shlomo Yoav; Hawkins James; Hollingworth William; Whiting Penny

    2012-01-01

    Abstract Background Identification of causes of dementia soon after symptom onset is important, because appropriate treatment of some causes of dementia can slow or halt its progression or enable symptomatic treatment where appropriate. The accuracy of MRI and CT, and whether MRI is superior to CT, in detecting a vascular component to dementia in autopsy confirmed and clinical cohorts of patients with VaD, combined AD and VaD (“mixed dementia”), and AD remain unclear. We conducted a systemati...

  1. Elevated radioxenon detected remotely following the Fukushima nuclear accident

    International Nuclear Information System (INIS)

    We report on the first measurements of short-lived gaseous fission products detected outside of Japan following the Fukushima nuclear releases, which occurred after a 9.0 magnitude earthquake and tsunami on March 11, 2011. The measurements were conducted at the Pacific Northwest National Laboratory (PNNL), (46o16'47''N, 119o16'53''W) located more than 7000 km from the emission point in Fukushima Japan (37o25'17''N, 141o1'57''E). First detections of 133Xe were made starting early March 16, only four days following the earthquake. Maximum concentrations of 133Xe were in excess of 40 Bq/m3, which is more than x40,000 the average concentration of this isotope is this part of the United States. - Highlights: ? First measurements of radioactivity detected outside of Japan following the nuclear reactor accident. ? High level description of the accident and the use of noble gas as an isotope that can be detected long range. ? Determination of the inventory of xenon-133 released from the accident.

  2. DETECTION OF ILLEGAL CANNABIS CULTIVATION USING REMOTE SENSING

    Science.gov (United States)

    Detection of illegal Cannabis cultivation by law enforcement agencies currently relies on low flying aircraft manned by trained aerial spotters. This is physically tiring for the aircrew, inefficient for large or complex landscapes, and is often foiled by camouflaged grow sites. A solution for det...

  3. Remotely-Sensed Detection of Foreclosure Effects on Residential Landscapes

    Science.gov (United States)

    Cutts, B.; Minn, M.; Pavlovic, N. R.; Greenberg, J. A.; Fraterrigo, J.; Turner, V. K.

    2014-12-01

    This project aims to understand whether the foreclosure crisis of 2007-2010 led to change in yard management with consequences for property and neighborhood land cover. By triangulating across analyses that vary in spatial and temporal resolution, this study examines whether foreclosure has resulted in changes in household and neighborhood vegetation structure. One common hypothesis is that the of financial distress is a reduction in lawn management (mowing, irrigating, and fertilizing ) due to economic constraint, vacancy or abandonment. However, changes in these practices differ across space as they are mediated by individual idiosyncrasies as well as complex social norms encoded in formal and informal institutions. The aim of our broader research project is to gain understanding of how foreclosure changes yard management within the context of these institutions. This poster presents preliminary results of analyses that aim to understand the relationship between foreclosure and land cover change in Maricopa County (Phoenix), Arizona. We synthesize foreclosure data with other social data sources focused on demographics, property characteristics, and vacancy to quantify both general and spatially dependent signatures of foreclosure in remotely-sensed NDVI data from MODIS and LANDSAT. Through results from multiple sources of data, we aim to isolate and describe signals that can be correlated with housing distress and foreclosure-induced vacancy. Arizona is analytically advantageous as area with an arid climate where the vegetation changes resulting from cessation of lawn maintenance are often dramatic and clearly observable. Our preliminary analysis indicates that there are specific NDVI signatures reflecting differing landscape-maintenance responses to foreclosure, supporting our central thesis that foreclosure influences land cover. These results provide a foundation upon which we will engage in both detailed investigation of the environmental effects of this phenomenon, as well as the social drivers that have result in the dramatic differences in behavior across space. The broader value of this project is to understand the short and long-term influences of foreclosure over human-environment relationships in urban and suburban developments.

  4. MRI-detected extramural vascular invasion is an independent prognostic factor for synchronous metastasis in patients with rectal cancer

    International Nuclear Information System (INIS)

    To determine whether magnetic resonance imaging (MRI)-detected extramural vascular invasion (EMVI) could predict synchronous distant metastases in rectal cancer. Patients who underwent rectal MRI between July 2011 and December 2012 were screened. This study included 447 patients with pathologically confirmed rectal adenocarcinoma who had undergone MRI without previous treatment. Distant metastases were recorded at the initial work-up and over a 6-month follow-up. Univariate/multivariate logistic regression models were used to determine the risk of metastasis. The diagnostic performance was calculated using pathologic lymphovascular invasion (LVI) as a gold standard. Among 447 patients, 79 patients (17.7 %) were confirmed to have distant metastases. Three MRI features are significantly associated with a high risk of distant metastasis: positive EMVI (odds ratio 3.02), high T stage (odds ratio 2.10) and positive regional lymph node metastasis (odds ratio 6.01). EMVI in a large vessel (?3 mm) had a higher risk for metastasis than EMVI in a small vessel (<3 mm). Sensitivity, specificity and accuracy of MRI-detected EMVI were 28.2 %, 94.0 % and 80.3 %, respectively. MRI-detected EMVI is an independent risk factor for synchronous metastasis in rectal cancer. EMVI in large vessels is a stronger risk factor for distant metastasis than EMVI in small vessels. (orig.)

  5. MRI-detected extramural vascular invasion is an independent prognostic factor for synchronous metastasis in patients with rectal cancer

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Beomseok; Lim, Joon-seok; Kim, Honsoul; Kim, Myeong-Jin [Yonsei University, College of Medicine, Department of Radiology and Research Institute of Radiological Science, Severance Hospital, Seoul (Korea, Republic of); Myoung, Sungmin [Jungwon University, Department of Medical Information, Goesan (Korea, Republic of); Choi, Junjeong [Yonsei University Wonju College of Medicine, Department of Pathology, Wonju (Korea, Republic of); Kim, Nam Kyu [Yonsei University, College of Medicine, Department of Surgery, Severance Hospital, Seoul (Korea, Republic of)

    2015-05-01

    To determine whether magnetic resonance imaging (MRI)-detected extramural vascular invasion (EMVI) could predict synchronous distant metastases in rectal cancer. Patients who underwent rectal MRI between July 2011 and December 2012 were screened. This study included 447 patients with pathologically confirmed rectal adenocarcinoma who had undergone MRI without previous treatment. Distant metastases were recorded at the initial work-up and over a 6-month follow-up. Univariate/multivariate logistic regression models were used to determine the risk of metastasis. The diagnostic performance was calculated using pathologic lymphovascular invasion (LVI) as a gold standard. Among 447 patients, 79 patients (17.7 %) were confirmed to have distant metastases. Three MRI features are significantly associated with a high risk of distant metastasis: positive EMVI (odds ratio 3.02), high T stage (odds ratio 2.10) and positive regional lymph node metastasis (odds ratio 6.01). EMVI in a large vessel (?3 mm) had a higher risk for metastasis than EMVI in a small vessel (<3 mm). Sensitivity, specificity and accuracy of MRI-detected EMVI were 28.2 %, 94.0 % and 80.3 %, respectively. MRI-detected EMVI is an independent risk factor for synchronous metastasis in rectal cancer. EMVI in large vessels is a stronger risk factor for distant metastasis than EMVI in small vessels. (orig.)

  6. Improved detection of localized prostate cancer using co-registered MRI and {sup 11}C-acetate PET/CT

    Energy Technology Data Exchange (ETDEWEB)

    Jambor, Ivan, E-mail: ivjamb@utu.fi [Department of Diagnostic Radiology, University of Turku, Turku (Finland); 2nd Department of Radiology, Comenius University and St. Elisabeth Oncology Institute, Bratislava (Slovakia); Turku PET Centre, University of Turku, Turku (Finland); Borra, Ronald, E-mail: ronald.borra@tyks.fi [Department of Diagnostic Radiology, University of Turku, Turku (Finland); Turku PET Centre, University of Turku, Turku (Finland); Medical Imaging Centre of Southwest Finland, Turku University Hospital, Turku (Finland); Kemppainen, Jukka, E-mail: Jukka.Kemppainen@tyks.fi [Turku PET Centre, University of Turku, Turku (Finland); Department of Clinical Physiology and Nuclear Medicine, Turku University Hospital, Turku (Finland); Lepomaeki, Virva, E-mail: Virva.Lepomaki@tyks.fi [Turku PET Centre, University of Turku, Turku (Finland); Parkkola, Riitta, E-mail: Riitta.Parkkola@tyks.fi [Department of Diagnostic Radiology, University of Turku, Turku (Finland); Turku PET Centre, University of Turku, Turku (Finland); Medical Imaging Centre of Southwest Finland, Turku University Hospital, Turku (Finland); Dean, Kirsti, E-mail: Kirsti.Dean@tyks.fi [Department of Diagnostic Radiology, University of Turku, Turku (Finland); Medical Imaging Centre of Southwest Finland, Turku University Hospital, Turku (Finland); Alanen, Kalle, E-mail: Kalle.Alanen@tyks.fi [Department of Pathology, Turku University Hospital, Turku (Finland); Arponen, Eveliina, E-mail: Eveliina.Arponen@utu.fi [Turku PET Centre, University of Turku, Turku (Finland); Nurmi, Martti, E-mail: Martti.Nurmi@tyks.fi [Department of Surgery, Division of Urology, Turku University Hospital, Turku (Finland); Aronen, Hannu J., E-mail: Hannu.Aronen@tyks.fi [Department of Diagnostic Radiology, University of Turku, Turku (Finland); Medical Imaging Centre of Southwest Finland, Turku University Hospital, Turku (Finland); and others

    2012-11-15

    Objectives: We aimed to study the ability of contrast enhanced MRI at 1.5 T and {sup 11}C-acetate PET/CT, both individually and using fused data, to detect localized prostate cancer. Methods: Thirty-six men with untreated prostate cancer and negative for metastatic disease on pelvic CT and bone scan were prospectively enrolled. A pelvic {sup 11}C-acetate PET/CT scan was performed in all patients, and a contrast enhanced MRI scan in 33 patients (6 examinations using both endorectal coil and surface coils, and 27 examinations using surface coils only). After the imaging studies 10 patients underwent prostatectomy and 26 were treated by image guided external beam radiation treatment. Image fusion of co-registered PET and MRI data was performed based on anatomical landmarks visible on CT and MRI using an advanced in-house developed software package. PET/CT, MRI and fused PET/MRI data were evaluated visually and compared with biopsy findings on a lobar level, while a sextant approach was used for patients undergoing prostatectomy. Results: When using biopsy samples as method of reference, the sensitivity, specificity and accuracy for visual detection of prostate cancer on a lobar level by contrast enhanced MRI was 85%, 37%, 73% and that of {sup 11}C-acetate PET/CT 88%, 41%, 74%, respectively. Fusion of PET with MRI data increased sensitivity, specificity and accuracy to 90%, 72% and 85%, respectively. Conclusions: Fusion of sequentially obtained PET/CT and MRI data for the localization of prostate cancer is feasible and superior to the performance of each individual modality alone.

  7. Remote sensing study of detecting of flaws in structural material

    Science.gov (United States)

    Okamoto, Yoshizo; Kaminaga, Fumito; Inagaki, Terumi; Numao, Tatsuya; Fukuzawa, Kimio; Ichikawa, Hiroya

    1993-04-01

    A new thermal radiation technique using an infrared radiometer has been developed to detect flaws of materials, such as inclusion, crack and pinhole. In the present study, several incident radiation energies like sun, lamp and gas, were injected to the test material with an artificial internal flaw. Transient radiation temperature image of the flaw on the CRT represents the existence of the internal flaw with higher radiation temperature than that of the surface without the flaw. The characteristics of various incident energy methods were compared with each other. The detecting limitation of internal flaws is determined by the surface temperature variance of the tested materials. The heat flow around the flaw was numerically analyzed by solving a heat conduction equation to verify the surface temperature behavior above the flaws.

  8. Remote Mine Detection Technologies for Land and Water Environments

    Energy Technology Data Exchange (ETDEWEB)

    Hoover, Eddie R.

    1999-05-11

    The detection of mines, both during and after hostilities, is a growing international problem. It limits military operations during wartime and unrecovered mines create tragic consequences for civilians. From a purely humanitarian standpoint an estimated 100 million or more unrecovered mines are located in over 60 countries worldwide. This paper presents an overview of some of the technologies currently being investigated by Sandia National Laboratories for the detection and monitoring of minefields in land and water environments. The three technical areas described in this paper are: 1) the development of new mathematical techniques for combining or fusing the data from multiple sources for enhanced decision-making; 2) an environmental fate and transport (EF&T) analysis approach that is central to improving trace chemical sensing technique; and 3) the investigation of an underwater range imaging device to aid in locating and characterizing mines and other obstacles in coastal waters.

  9. Remote Detection of Explosive Molecules by a Microfluidic SERS Device

    Science.gov (United States)

    Piorek, Brian; Lee, Seung Joon; Moskovits, Martin; Banerjee, Sanjoy; Meinhart, Carl

    2007-11-01

    Free-surface microfluidics (FSF) is combined with surface-enhanced Raman spectroscopy (SERS) to detect trace explosives vapors at room temperature and pressure. A free surface, with a large surface to volume ratio, is created using an open microchannel. Since surface tension is a dominant force at the microscale, it can be used to confine the fluid in the microchannel and create a pressure gradient to drive the flow with velocities ranging from ˜ 1um/s - 1mm/s. The curvature of the free surface is measured by confocal microscopy in order to determine the local Laplace pressure in the free-surface microchannel flow. The system has been used for the molecular-specific detection of vapor emanated from explosives such as DNT, TNT and picric acid. The system does not show signs of performance degradation from common interferents such as saturated gasoline vapor and perfume.

  10. Early-Stage White Matter Lesions Detected by Multispectral MRI Segmentation Predict Progressive Cognitive Decline

    Science.gov (United States)

    Jokinen, Hanna; Gonçalves, Nicolau; Vigário, Ricardo; Lipsanen, Jari; Fazekas, Franz; Schmidt, Reinhold; Barkhof, Frederik; Madureira, Sofia; Verdelho, Ana; Inzitari, Domenico; Pantoni, Leonardo; Erkinjuntti, Timo

    2015-01-01

    White matter lesions (WML) are the main brain imaging surrogate of cerebral small-vessel disease. A new MRI tissue segmentation method, based on a discriminative clustering approach without explicit model-based added prior, detects partial WML volumes, likely representing very early-stage changes in normal-appearing brain tissue. This study investigated how the different stages of WML, from a “pre-visible” stage to fully developed lesions, predict future cognitive decline. MRI scans of 78 subjects, aged 65–84 years, from the Leukoaraiosis and Disability (LADIS) study were analyzed using a self-supervised multispectral segmentation algorithm to identify tissue types and partial WML volumes. Each lesion voxel was classified as having a small (33%), intermediate (66%), or high (100%) proportion of lesion tissue. The subjects were evaluated with detailed clinical and neuropsychological assessments at baseline and at three annual follow-up visits. We found that voxels with small partial WML predicted lower executive function compound scores at baseline, and steeper decline of executive scores in follow-up, independently of the demographics and the conventionally estimated hyperintensity volume on fluid-attenuated inversion recovery images. The intermediate and fully developed lesions were related to impairments in multiple cognitive domains including executive functions, processing speed, memory, and global cognitive function. In conclusion, early-stage partial WML, still too faint to be clearly detectable on conventional MRI, already predict executive dysfunction and progressive cognitive decline regardless of the conventionally evaluated WML load. These findings advance early recognition of small vessel disease and incipient vascular cognitive impairment. PMID:26696814

  11. Intraoperative detection of glioma invasion beyond MRI enhancement with Raman spectroscopy in humans

    Science.gov (United States)

    Jermyn, Michael; Mok, Kelvin; Mercier, Jeanne; Desroches, Joannie; Pichette, Julien; Saint-Arnaud, Karl; Guiot, Marie-Christine; Petrecca, Kevin; Leblond, Frédéric

    2015-03-01

    Cancer tissue is frequently impossible to distinguish from normal brain during surgery. Gliomas are a class of brain cancer which invade into the normal brain. If left unresected, these invasive cancer cells are the source of glioma recurrence. Moreover, these invasion areas do not show up on standard-of-care pre-operative Magnetic Resonance Imaging (MRI). This inability to fully visualize invasive brain cancers results in subtotal surgical resections, negatively impacting patient survival. To address this issue, we have demonstrated the efficacy of single-point in vivo Raman spectroscopy using a contact hand-held fiber optic probe for rapid detection of cancer invasion in 8 patients with low and high grade gliomas. Using a supervised machine learning algorithm to analyze the Raman spectra obtained in vivo, we were able to distinguish normal brain from the presence of cancer cells with sensitivity and specificity greater than 90%. Moreover, by correlating these results with pre-operative MRI we demonstrate the ability to detect low density cancer invasion up to 1.5cm beyond the cancer extent visible using MRI. This represents the potential for significant improvements in progression-free and overall patient survival, by identifying previously undetectable residual cancer cell populations and preventing the resection of normal brain tissue. While the importance of maximizing the volume of tumor resection is important for all grades of gliomas, the impact for low grade gliomas can be dramatic because surgery can even be curative. This convenient technology can rapidly classify cancer invasion in real-time, making it ideal for intraoperative use in brain tumor resection.

  12. HICO and RAIDS Experiment Payload - Remote Atmospheric and Ionospheric Detection System (RAIDS)

    Science.gov (United States)

    Budzien, Scott

    2009-01-01

    The HICO and RAIDS Experiment Payload - Remote Atmospheric and Ionospheric Detection System (HREP-RAIDS) experiment will provide atmospheric scientists with a complete description of the major constituents of the thermosphere (layer of the Earth's atmosphere) and ionosphere (uppermost layer of the Earth's atmosphere), global electron density profiles at altitudes between 100 - 350 kilometers.

  13. Temporal Forest Change Detection and Forest Health Assessment using Remote Sensing

    Science.gov (United States)

    Ya'acob, Norsuzila; Mohd Azize, Aziean Binti; Anis Mahmon, Nur; Laily Yusof, Azita; Farhana Azmi, Nor; Mustafa, Norfazira

    2014-03-01

    This paper presents the detection of Angsi and Berembun Reserve Forest change for years 1996 and 2013. Forest is an important part of our ecosystem. The main function is to absorb carbon oxide and produce oxygen in their cycle of photosynthesis to maintain a balance and healthy atmosphere. However, forest changes as time changes. Some changes are necessary as to give way for economic growth. Nevertheless, it is important to monitor forest change so that deforestation and development can be planned and the balance of ecosystem is still preserved. It is important because there are number of unfavorable effects of deforestation that include environmental and economic such as erosion of soil, loss of biodiversity and climate change. The forest change detection can be studied with reference of several satellite images using remote sensing application. Forest change detection is best done with remote sensing due to large and remote study area. The objective of this project is to detect forest change over time and to compare forest health indicated by Normalized Difference Vegetation Index (NDVI) using remote sensing and image processing. The forest under study shows depletion of forest area by 12% and 100% increment of deforestation activities. The NDVI value which is associated with the forest health also shows 13% of reduction.

  14. Feasibility study of contaminant detection for food with ULF-NMR/MRI system using HTS-SQUID

    International Nuclear Information System (INIS)

    Highlights: •Feasibility of application of ultra-low field (ULF) NMR/MRI was studied. •ULF-NMR/MRI system utilized HTS-rf-SQUID and permanent magnet of 1.1 T. •Magnetic contaminants in water were successfully detected by NMR measurements. •Non-magnetic contaminants in water were distinguished by 1D-MRI measurements. -- Abstract: We have developed an ultra-low frequency (ULF) nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) system utilizing an HTS-SQUID for an application of contaminant detection in food and drink. In the system, a permanent magnet of 1.1 T was used to pre-polarize protons in a water sample. We measured NMR signals from water samples with or without various contaminants, such as stainless steel (SUS304), aluminum, and glass balls using the system. In the case that the contaminant was the SUS304 ball, the NMR signal intensity was reduced compared to that from the sample without the contaminant due to the remnant field of the contaminant. One-dimensional (1D) MRIs of the samples were also acquired to detect non-magnetic contaminants. In the 1D MRIs, changes of the MRI spectra were detected, corresponding to positions of the contaminants. These results show that the feasibility of the system to detect various contaminants in foods

  15. Feasibility study of contaminant detection for food with ULF-NMR/MRI system using HTS-SQUID

    Energy Technology Data Exchange (ETDEWEB)

    Hatsukade, Yoshimi, E-mail: hatukade@ens.tut.ac.jp; Tsunaki, Shingo; Yamamoto, Masaaki; Abe, Takayuki; Hatta, Junichi; Tanaka, Saburo

    2013-11-15

    Highlights: •Feasibility of application of ultra-low field (ULF) NMR/MRI was studied. •ULF-NMR/MRI system utilized HTS-rf-SQUID and permanent magnet of 1.1 T. •Magnetic contaminants in water were successfully detected by NMR measurements. •Non-magnetic contaminants in water were distinguished by 1D-MRI measurements. -- Abstract: We have developed an ultra-low frequency (ULF) nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) system utilizing an HTS-SQUID for an application of contaminant detection in food and drink. In the system, a permanent magnet of 1.1 T was used to pre-polarize protons in a water sample. We measured NMR signals from water samples with or without various contaminants, such as stainless steel (SUS304), aluminum, and glass balls using the system. In the case that the contaminant was the SUS304 ball, the NMR signal intensity was reduced compared to that from the sample without the contaminant due to the remnant field of the contaminant. One-dimensional (1D) MRIs of the samples were also acquired to detect non-magnetic contaminants. In the 1D MRIs, changes of the MRI spectra were detected, corresponding to positions of the contaminants. These results show that the feasibility of the system to detect various contaminants in foods.

  16. Multifunctional fiber-optic microwave links based on remote heterodyne detection

    OpenAIRE

    Gliese, Ulrik Bo; Nielsen, Torben Nørskov; Nielsen, Søren Nørskov; Stubkjær, Kristian

    1998-01-01

    The multifunctionality of microwave links based on remote heterodyne detection (RHD) of signals from a dual-frequency laser transmitter is discussed and experimentally demonstrated in this paper. Typically, direct detection (DD) in conjunction with optical intensity modulation is used to implement fiber-optic microwave links. The resulting links are inherently transparent. As opposed to DD links, RHD links can perform radio-system functionalities such as modulation and frequency conversion in...

  17. Brain MRI Tumor Detection using Active Contour Model and Local Image Fitting Energy

    Science.gov (United States)

    Nabizadeh, Nooshin; John, Nigel

    2014-03-01

    Automatic abnormality detection in Magnetic Resonance Imaging (MRI) is an important issue in many diagnostic and therapeutic applications. Here an automatic brain tumor detection method is introduced that uses T1-weighted images and K. Zhang et. al.'s active contour model driven by local image fitting (LIF) energy. Local image fitting energy obtains the local image information, which enables the algorithm to segment images with intensity inhomogeneities. Advantage of this method is that the LIF energy functional has less computational complexity than the local binary fitting (LBF) energy functional; moreover, it maintains the sub-pixel accuracy and boundary regularization properties. In Zhang's algorithm, a new level set method based on Gaussian filtering is used to implement the variational formulation, which is not only vigorous to prevent the energy functional from being trapped into local minimum, but also effective in keeping the level set function regular. Experiments show that the proposed method achieves high accuracy brain tumor segmentation results.

  18. Diagnostic performance of MRI for detection of intestinal fistulas in patients with complicated inflammatory bowel conditions

    International Nuclear Information System (INIS)

    The diagnostic performance of magnetic resonance imaging (MRI) for detection of intestinal fistulas, other than perianal, in patients with known complicated inflammatory bowel conditions (CIBC) was investigated. Our study group consisted of 20 patients (12 women, mean age 43 years) with CIBC, including Crohn's disease (n=13), colonic diverticulitis (n=3), colitis after radiotherapy (n=3) and of postoperative origin (n=1). Eleven surgically proven enteral fistulas were known in ten (50%) of these patients, being of enterovesical (n=3), enterocolic (n=2), enteroenteral (n=2), rectovaginal (n=2), rectovaginovesical (n=1) and of entercutaneous (n=1) localisation. The other ten patients (50%), used as the control group, showed MR features of CIBC, although without any fistulous tract. Multiplanar T1- and T2-weighted sequences had been performed, including gadolinium-enhanced acquisition with fat saturation (1.5 T). MR findings were independently blindly and retrospectively reviewed by three radiologists for the presence and etiology of any fistula, as well as visualization and characterization of the fistulous tract. Results were compared with surgical findings (n=16) and clinical evolution (n=4). Interobserver agreement was calculated. Interobserver agreement kappa for fistula detection was 0.71. Overall sensitivity, specificity and accuracy for fistula detection were 78.6%, 75% and 77.2%, respectively. Sensitivity for fistula characterization was 80.6%, with visualization of the fistulous tract in all cases, whereby T1-weighted gadolinium-enhanced fat-saturated images were considered the most useful sequences. Gadolinium-enhanced MRI is a reliable and reproducible tool for detection of enteral fistulas secondary to inflammatory conditions. (orig.)

  19. Detection of suspected placental invasion by MRI: Do the results depend on observer’ experience?

    International Nuclear Information System (INIS)

    Purpose: To evaluate the diagnostic value of previously described MR features used for detecting suspected placental invasion according to observers’ experience. Materials and methods: Our population included 25 pregnant women (mean age 35.16) investigated by prenatal MRI (1.5 T, T1- and T2-weighted MR-sequences without i.v. contrast), among them 12 with histopathologically proven placental invasion and 13 women (52%) without placental invasion used as control group. Two senior and two junior radiologists blindly and independently reviewed MR-examinations in view of 6 previously defined MR-features indicating presence and degree of placental invasion (placenta increta, accreta or percreta). For each reader the sensibility, specificity, and receiver operating curve (ROC) were calculated. Interobserver agreements between senior and junior readers were determined. Stepwise logistic regression was performed including the 6 MR-features predictive of placental invasion. Results: Demographics between both groups were statistically equivalent. Overall sensitivity and specificity for placental invasion was 90.9% and 75.0% for seniors and 81.8% and 61.8% for juniors, respectively. The best single MR-feature indicating placental invasion was T2-hypointense placental bands (r2 = 0.28), followed by focally interrupted myometrial border, infiltration of pelvic organs and tenting of the bladder (r2 = 0.36). Interobserver agreement for detecting placental invasion was 0.64 for seniors and 0.41 for juniors, thus substantial and moderate, respectively. Seniors detected placental invasion and depth of infiltration with significantly higher diagnostic certitude than juniors (p = 0.0002 and p = 0.0282, respectively). Conclusion: MRI can be a reliable and reproducible tool for the detection of suspected placental invasion, but the diagnostic value significantly depends on observers’ experience

  20. Detection of suspected placental invasion by MRI: Do the results depend on observer’ experience?

    Energy Technology Data Exchange (ETDEWEB)

    Alamo, Leonor, E-mail: leonor.alamo@chuv.ch [Centre Hospitalier Universitaire Vaudois, Lausanne (Switzerland); Anaye, Anass; Rey, Jannick; Denys, Alban [Centre Hospitalier Universitaire Vaudois, Lausanne (Switzerland); Bongartz, Georg [Universitätsspital Basel (Switzerland); Terraz, Sylvain [Hôpitaux Universitaires Genève (Switzerland); Artemisia, Simona; Meuli, Reto; Schmidt, Sabine [Centre Hospitalier Universitaire Vaudois, Lausanne (Switzerland)

    2013-02-15

    Purpose: To evaluate the diagnostic value of previously described MR features used for detecting suspected placental invasion according to observers’ experience. Materials and methods: Our population included 25 pregnant women (mean age 35.16) investigated by prenatal MRI (1.5 T, T1- and T2-weighted MR-sequences without i.v. contrast), among them 12 with histopathologically proven placental invasion and 13 women (52%) without placental invasion used as control group. Two senior and two junior radiologists blindly and independently reviewed MR-examinations in view of 6 previously defined MR-features indicating presence and degree of placental invasion (placenta increta, accreta or percreta). For each reader the sensibility, specificity, and receiver operating curve (ROC) were calculated. Interobserver agreements between senior and junior readers were determined. Stepwise logistic regression was performed including the 6 MR-features predictive of placental invasion. Results: Demographics between both groups were statistically equivalent. Overall sensitivity and specificity for placental invasion was 90.9% and 75.0% for seniors and 81.8% and 61.8% for juniors, respectively. The best single MR-feature indicating placental invasion was T2-hypointense placental bands (r{sup 2} = 0.28), followed by focally interrupted myometrial border, infiltration of pelvic organs and tenting of the bladder (r{sup 2} = 0.36). Interobserver agreement for detecting placental invasion was 0.64 for seniors and 0.41 for juniors, thus substantial and moderate, respectively. Seniors detected placental invasion and depth of infiltration with significantly higher diagnostic certitude than juniors (p = 0.0002 and p = 0.0282, respectively). Conclusion: MRI can be a reliable and reproducible tool for the detection of suspected placental invasion, but the diagnostic value significantly depends on observers’ experience.

  1. Diagnostic performance of MRI for detection of intestinal fistulas in patients with complicated inflammatory bowel conditions

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, S.; Meuwly, J.Y.; Meuli, R.; Schnyder, P.; Denys, A. [Universitaire Vaudois - CHUV, Service de radiodiagnostic et radiologie interventionnelle, Centre Hospitalier, Lausanne (Switzerland); Chevallier, P. [Hopital Archet II, Imagerie Medicale, Nice (France); Bessoud, B. [Hopital Kremlin-Bicetre, Radiologie Generale, Kremlin-Bicetre (France); Felley, C. [University Hospital, CHUV, Service de Gastroenterologie, Lausanne (Switzerland)

    2007-11-15

    The diagnostic performance of magnetic resonance imaging (MRI) for detection of intestinal fistulas, other than perianal, in patients with known complicated inflammatory bowel conditions (CIBC) was investigated. Our study group consisted of 20 patients (12 women, mean age 43 years) with CIBC, including Crohn's disease (n=13), colonic diverticulitis (n=3), colitis after radiotherapy (n=3) and of postoperative origin (n=1). Eleven surgically proven enteral fistulas were known in ten (50%) of these patients, being of enterovesical (n=3), enterocolic (n=2), enteroenteral (n=2), rectovaginal (n=2), rectovaginovesical (n=1) and of entercutaneous (n=1) localisation. The other ten patients (50%), used as the control group, showed MR features of CIBC, although without any fistulous tract. Multiplanar T1- and T2-weighted sequences had been performed, including gadolinium-enhanced acquisition with fat saturation (1.5 T). MR findings were independently blindly and retrospectively reviewed by three radiologists for the presence and etiology of any fistula, as well as visualization and characterization of the fistulous tract. Results were compared with surgical findings (n=16) and clinical evolution (n=4). Interobserver agreement was calculated. Interobserver agreement kappa for fistula detection was 0.71. Overall sensitivity, specificity and accuracy for fistula detection were 78.6%, 75% and 77.2%, respectively. Sensitivity for fistula characterization was 80.6%, with visualization of the fistulous tract in all cases, whereby T1-weighted gadolinium-enhanced fat-saturated images were considered the most useful sequences. Gadolinium-enhanced MRI is a reliable and reproducible tool for detection of enteral fistulas secondary to inflammatory conditions. (orig.)

  2. Multispectral index for the remote detection of human skin signatures

    Science.gov (United States)

    Baranoski, Gladimir V. G.; Chen, Tenn F.

    2015-07-01

    We propose a multispectral index to assist the detection of human signatures in complex natural environments. Differently from previously proposed indices, it takes into account the spectral responses of human skin not only in the near infrared, but also in the visible region of the light spectrum. As a result, it can contribute to mitigate the chances of false alarms during time-critical search and rescue operations carried out in such environments. Our investigation is supported by the use of reflectance data measured for different skin specimens and natural materials such as sand, ocean water, melting snow, and forest vegetation. We believe that the observations reported in this work can be incorporated into the design of more effective procedures and devices for the differentiation of human targets from background materials commonly found in nature.

  3. Image analysis, classification, and change detection in remote sensing with algorithms for ENVI/IDL

    CERN Document Server

    Canty, Morton J

    2011-01-01

    Demonstrating the breadth and depth of growth in the field since the publication of the popular first edition, Image Analysis, Classification and Change Detection in Remote Sensing, with Algorithms for ENVI/IDL, Second Edition has been updated and expanded to keep pace with the latest versions of the ENVI software environment. Effectively interweaving theory, algorithms, and computer codes, the text supplies an accessible introduction to the techniques used in the processing of remotely sensed imagery. This significantly expanded edition presents numerous image analysis examples and algorithms

  4. Value of FDG-PET vs MRI/CT in detection and staging of early uterine cervical cancer

    International Nuclear Information System (INIS)

    This prospective study was performed to define the efficiency of FDG-PET in detecting primaries and in preoperatively assessing lymph node metastases of cervical cancer. Forty one patients with cervical cancer were investigated with PET (370 MBq F-18-FDG, Siemens ECAT EXACT HR+, visual evaluation) and MRI prior radical hysterectomy with pelvic, and additionally 12 cases paraortal, lymphadenectomies. Histopathological evaluation verified in all cases the evidence of cervical cancer except in one case, where the tumor was completely removed by conisation procedure. Sensitivity of PET and MRI were 95% and 85%, respectively. In 16/82 pelvic lymph node sites metastases were histologically detected (7 x micrometastases). Sensitivity, specificity, positive positive and negative predictive value were 50%, 85%, 44% and 88% for PET and 31%, 90%, 40% and 86% for MRI. Out of the 12 cases with dissection of paraortal lymph nodes, metastases were found histologically in 3 cases. PET detected 2/3 truly with no false positive result while CT detected 0/3 cases with no false positive findings. It is concluded that PET can detect cervical cancer with high accuracy. The accuracy of PET and MRI was similar for detection of pelvic metastases. Both methods have limited sensitivity due to the high incidence of micrometastases. PET was more accurate than CT in detection of paraortal metastases

  5. Remote calorimetric detection of urea via flow injection analysis.

    Science.gov (United States)

    Gaddes, David E; Demirel, Melik C; Reeves, W Brian; Tadigadapa, Srinivas

    2015-11-01

    The design and development of a calorimetric biosensing system enabling relatively high throughput sample analysis are reported. The calorimetric biosensor system consists of a thin (?20 ?m) micromachined Y-cut quartz crystal resonator (QCR) as a temperature sensor placed in close proximity to a fluidic chamber packed with an immobilized enzyme. Layer by layer enzyme immobilization of urease is demonstrated and its activity as a function of the number of layers, pH, and time has been evaluated. This configuration enables a sensing system where a transducer element is physically separated from the analyte solution of interest and is thereby free from fouling effects typically associated with biochemical reactions occuring on the sensor surface. The performance of this biosensing system is demonstrated by detection of 1-200 mM urea in phosphate buffer via a flow injection analysis (FIA) technique. Miniaturized fluidic systems were used to provide continuous flow through a reaction column. Under this configuration the biosensor has an ultimate resolution of less than 1 mM urea and showed a linear response between 0-50 mM. This work demonstrates a sensing modality in which the sensor itself is not fouled or contaminated by the solution of interest and the enzyme immobilized Kapton® fluidic reaction column can be used as a disposable cartridge. Such a system enables reuse and reliability for long term sampling measurements. Based on this concept a biosensing system is envisioned which can perform rapid measurements to detect biomarkers such as glucose, creatinine, cholesterol, urea and lactate in urine and blood continuously over extended periods of time. PMID:26479269

  6. Change Detection and Dynamic Analysis Based on Remote Sensing Images

    Science.gov (United States)

    Luzi, G.; Crosetto, M.; Devanthéry, N.; Cuevas, M.; Meng, X.

    2013-08-01

    A radar uses the time elapsed between the transmission and reception of an electromagnetic waveform to locate targets present in the illuminated area. Different objects will reflect the radiation with different intensities and phase. The signal provided by standard radar is a profile of the intensity backscattered from the scene as a function of the distance. The resolution, i.e. the capability to distinguish different targets, is related to instrumental parameters and, for conventional radar, is in the range of tens of centimetres. The elementary sampling volume of a radar measurement is usually called radar bin. A radar image can be obtained when an azimuth and a range resolution is available, and this can be attained in different ways: performing a mechanical scanning of the antenna, the most familiar mode used for surveillance, meteorological radar etc, or modifying its spatial features by changing the characteristics of the radiated signal or finally through a specific processing of the acquired data, as in the case of Synthetic Aperture Radar (SAR). In this paper only 1D data without any cross range resolution are used. The vibration of a target corresponds to a small and rapid variation of the radar-target distance to which the phase of the received signal is related. Coherent radar is able to provide measurements of the phase variation along time exploiting the interferometric technique. The received radar signals permits to retrieve distance variations of the observed objects in the order of small fractions of the transmitted wavelength, by comparing the phase of signals acquired at different times. Use a short span bridge as a test-bed this study investigates the actual capability of a Real Aperture Radar (RAR) interferometer to detect the natural vibration caused by wind or pass pedestrians. It is found that RAR can pick up bridge displacements of a few tens of μm and detect a wide range of vibrations.

  7. A new method of inshore ship detection in high-resolution optical remote sensing images

    Science.gov (United States)

    Hu, Qifeng; Du, Yaling; Jiang, Yunqiu; Ming, Delie

    2015-10-01

    Ship as an important military target and water transportation, of which the detection has great significance. In the military field, the automatic detection of ships can be used to monitor ship dynamic in the harbor and maritime of enemy, and then analyze the enemy naval power. In civilian field, the automatic detection of ships can be used in monitoring transportation of harbor and illegal behaviors such as illegal fishing, smuggling and pirates, etc. In recent years, research of ship detection is mainly concentrated in three categories: forward-looking infrared images, downward-looking SAR image, and optical remote sensing images with sea background. Little research has been done into ship detection of optical remote sensing images with harbor background, as the gray-scale and texture features of ships are similar to the coast in high-resolution optical remote sensing images. In this paper, we put forward an effective harbor ship target detection method. First of all, in order to overcome the shortage of the traditional difference method in obtaining histogram valley as the segmentation threshold, we propose an iterative histogram valley segmentation method which separates the harbor and ships from the water quite well. Secondly, as landing ships in optical remote sensing images usually lead to discontinuous harbor edges, we use Hough Transform method to extract harbor edges. First, lines are detected by Hough Transform. Then, lines that have similar slope are connected into a new line, thus we access continuous harbor edges. Secondary segmentation on the result of the land-and-sea separation, we eventually get the ships. At last, we calculate the aspect ratio of the ROIs, thereby remove those targets which are not ship. The experiment results show that our method has good robustness and can tolerate a certain degree of noise and occlusion.

  8. Incident and Traffic-Bottleneck Detection Algorithm in High-Resolution Remote Sensing Imagery

    Directory of Open Access Journals (Sweden)

    S.M.M. Kahaki

    2012-09-01

    Full Text Available One of the most important methods to solve traffic congestion is to detect the incident state of a roadway. This paper describes the development of a method for road traffic monitoring aimed at the acquisition and analysis of remote sensing imagery. We propose a strategy for road extraction, vehicle detection and incident detection from remote sensing imagery using techniques based on neural networks, Radon transform for angle detection and traffic-flow measurements. Traffic-bottleneck detection is another method that is proposed for recognizing incidents in both offline and real-time mode. Traffic flows and incidents are extracted from aerial images of bottleneck zones. The results show that the proposed approach has a reasonable detection performance compared to other methods. The best performance of the learning system was a detection rate of 87% and a false alarm rate of less than 18% on 45 aerial images of roadways. The performance of the traffic-bottleneck detection method had a detection rate of 87.5%.

  9. AIRBORNE, OPTICAL REMOTE SENSNG OF METHANE AND ETHANE FOR NATURAL GAS PIPELINE LEAK DETECTION

    Energy Technology Data Exchange (ETDEWEB)

    Jerry Myers

    2005-04-15

    Ophir Corporation was awarded a contract by the U. S. Department of Energy, National Energy Technology Laboratory under the Project Title ''Airborne, Optical Remote Sensing of Methane and Ethane for Natural Gas Pipeline Leak Detection'' on October 14, 2002. The scope of the work involved designing and developing an airborne, optical remote sensor capable of sensing methane and, if possible, ethane for the detection of natural gas pipeline leaks. Flight testing using a custom dual wavelength, high power fiber amplifier was initiated in February 2005. Ophir successfully demonstrated the airborne system, showing that it was capable of discerning small amounts of methane from a simulated pipeline leak. Leak rates as low as 150 standard cubic feet per hour (scf/h) were detected by the airborne sensor.

  10. RoboHound:developing sample collection and preconcentration hardware for a remote trace explosives detection system.

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, David J. (New Mexico Tech, Socorro, NM); Denning, David J.; Hobart, Clinton G.; Lenz, Michael C.; Anderson, Robert J.; Carlson, Dennis L.; Hunter, John Anthony; Gladwell, T. Scott; Mitchell, Mary-Anne; Hannum, David W.; Baumann, Mark J.

    2005-09-01

    The RoboHound{trademark} Project was a three-year, multiphase project at Sandia National Laboratories to build and refine a working prototype trace explosive detection system as a tool for a commercial robot. The RoboHound system was envisioned to be a tool for emergency responders to test suspicious items (i.e., packages or vehicles) for explosives while maintaining a safe distance. The project investigated combining Sandia's expertise in trace explosives detection with a wheeled robotic platform that could be programmed to interrogate suspicious items remotely for the presence of explosives. All of the RoboHound field tests were successful, especially with regards to the ability to collect and detect trace samples of RDX. The project has gone from remote sampling with human intervention to a fully automatic system that requires no human intervention until the robot returns from a sortie. A proposal is being made for additional work leading towards commercialization.

  11. Can Remote Sensing Detect Aquifer Characteristics?: A Case Study in the Guarani Aquifer System

    Science.gov (United States)

    Richey, A. S.; Thomas, B.; Famiglietti, J. S.

    2013-12-01

    Global water supply resiliency depends on groundwater, especially regions threatened by population growth and climate change. Aquifer characteristics, even as basic as confined versus unconfined, are necessary to prescribe regulations to sustainably manage groundwater supplies. A significant barrier to sustainable groundwater management exists in the difficulties associated with mapping groundwater resources and characteristics at a large spatial scale. This study addresses this challenge by investigating if remote sensing, including with NASA's Gravity Recovery and Climate Experiment (GRACE), can detect and quantify key aquifer parameters and characteristics. We explore this through a case study in the Guarani Aquifer System (GAS) of South America, validating our remote sensing-based findings against the best available regional estimates. The use of remote sensing to advance the understanding of large aquifers is beneficial to sustainable groundwater management, especially in a trans-boundary system, where consistent information exchange can occur within hydrologic boundaries instead of political boundaries.

  12. Brain Tumor Detection and Classification Using Deep Learning Classifier on MRI Images

    Directory of Open Access Journals (Sweden)

    V.P. Gladis Pushpa Rathi

    2015-05-01

    Full Text Available Magnetic Resonance Imaging (MRI has become an effective tool for clinical research in recent years and has found itself in applications such as brain tumour detection. In this study, tumor classification using multiple kernel-based probabilistic clustering and deep learning classifier is proposed. The proposed technique consists of three modules, namely segmentation module, feature extraction module and classification module. Initially, the MRI image is pre-processed to make it fit for segmentation and de-noising process is carried out using median filter. Then, pre-processed image is segmented using Multiple Kernel based Probabilistic Clustering (MKPC. Subsequently, features are extracted for every segment based on the shape, texture and intensity. After features extraction, important features will be selected using Linear Discriminant Analysis (LDA for classification purpose. Finally, deep learning classifier is employed for classification into tumor or non-tumor. The proposed technique is evaluated using sensitivity, specificity and accuracy. The proposed technique results are also compared with existing technique which uses Feed-Forward Back Propagation Network (FFBN. The proposed technique achieved an average sensitivity, specificity and accuracy of 0.88, 0.80 and 0.83, respectively with the highest values as about 1, 0.85 and 0.94. Improved results show the efficiency of the proposed technique.

  13. Detection of hepatocellular carcinoma in gadoxetic acid-enhanced MRI and diffusion-weighted MRI with respect to the severity of liver cirrhosis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ah Yeong; Kim, Young Kon; Lee, Min Woo; Park, Min Jung; Hwang, Jiyoung; Lee, Mi Hee; Lee, Jae Won [Dept. of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan Univ. School of Medicine, Seoul (Korea, Republic of)], e-mail: jmyr@dreamwiz.com

    2012-10-15

    Background As gadoxetic acid-enhanced magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) have been widely used for the evaluation of hepatocellular carcinoma (HCC), it is clinically relevant to determine the diagnostic efficacy of gadoxetic acid-enhanced MRI and DWI for detection of HCCs with respect to the severity of liver cirrhosis. Purpose To compare the diagnostic accuracy and sensitivity of gadoxetic acid-enhanced MRI and DWI for detection of HCCs with respect to the severity of liver cirrhosis. Material and Methods A total of 189 patients with 240 HCCs ({<=}3.0 cm) (Child-Pugh A, 81 patients with 90 HCCs; Child-Pugh B, 65 patients with 85 HCCs; Child-Pugh C, 43 patients with 65 HCCs) underwent DWI and gadoxetic acid-enhanced MRI at 3.0 T. A gadoxetic acid set (dynamic and hepatobiliary phase plus T2-weighted image) and DWI set (DWI plus unenhanced MRIs) for each Child-Pugh class were analyzed independently by two observers for detecting HCCs using receiver-operating characteristic analysis. The diagnostic accuracy and sensitivity were calculated. Results There was a trend toward decreased diagnostic accuracy for gadoxetic acid and DWI set with respect to the severity of cirrhosis (Child-Pugh A [mean 0.974, 0.961], B [mean 0.904, 0.863], C [mean 0.779, 0.760]). For both observers, the sensitivities of both image sets were highest in Child-Pugh class A (mean 95.6%, 93.9%), followed by class B (mean 83.0%, 77.1%), and class C (mean 60.6%, 60.0%) (P < 0.05). Conclusion In HCC detection, the diagnostic accuracy and sensitivity for gadoxetic acid-enhanced MRI and DWI were highest in Child-Pugh class A, followed by Child-Pugh class B, and Child-Pugh class C, indicating a tendency toward decreased diagnostic capability with the severity of cirrhosis.

  14. Detection of hepatocellular carcinoma in gadoxetic acid-enhanced MRI and diffusion-weighted MRI with respect to the severity of liver cirrhosis

    International Nuclear Information System (INIS)

    Background As gadoxetic acid-enhanced magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) have been widely used for the evaluation of hepatocellular carcinoma (HCC), it is clinically relevant to determine the diagnostic efficacy of gadoxetic acid-enhanced MRI and DWI for detection of HCCs with respect to the severity of liver cirrhosis. Purpose To compare the diagnostic accuracy and sensitivity of gadoxetic acid-enhanced MRI and DWI for detection of HCCs with respect to the severity of liver cirrhosis. Material and Methods A total of 189 patients with 240 HCCs (?3.0 cm) (Child-Pugh A, 81 patients with 90 HCCs; Child-Pugh B, 65 patients with 85 HCCs; Child-Pugh C, 43 patients with 65 HCCs) underwent DWI and gadoxetic acid-enhanced MRI at 3.0 T. A gadoxetic acid set (dynamic and hepatobiliary phase plus T2-weighted image) and DWI set (DWI plus unenhanced MRIs) for each Child-Pugh class were analyzed independently by two observers for detecting HCCs using receiver-operating characteristic analysis. The diagnostic accuracy and sensitivity were calculated. Results There was a trend toward decreased diagnostic accuracy for gadoxetic acid and DWI set with respect to the severity of cirrhosis (Child-Pugh A [mean 0.974, 0.961], B [mean 0.904, 0.863], C [mean 0.779, 0.760]). For both observers, the sensitivities of both image sets were highest in Child-Pugh class A (mean 95.6%, 93.9%), followed by class B (mean 83.0%, 77.1%), and class C (mean 60.6%, 60.0%) (P < 0.05). Conclusion In HCC detection, the diagnostic accuracy and sensitivity for gadoxetic acid-enhanced MRI and DWI were highest in Child-Pugh class A, followed by Child-Pugh class B, and Child-Pugh class C, indicating a tendency toward decreased diagnostic capability with the severity of cirrhosis

  15. Breast MRI, digital mammography and breast tomosynthesis: Comparison of three methods for early detection of breast cancer

    OpenAIRE

    Dragana Roganovic; Dragana Djilas; Sasa Vujnovic; Dag Pavic; Dragan Stojanov

    2015-01-01

    Breast cancer is the most common malignancy in women and early detection is important for its successful treatment. The aim of this study was to investigate the sensitivity and specificity of three methods for early detection of breast cancer: breast magnetic resonance imaging (MRI), digital mammography, and breast tomosynthesis in comparison to histopathology, as well as to investigate the intraindividual variability between these modalities.  We included 57 breast lesions, each detected by ...

  16. Remote bioaerosol detection using a broadband 1.5-micron laser

    Science.gov (United States)

    Wood, Nicholas J.; Gillespie, James B.; Ligon, David A.

    2004-12-01

    Bioaerosol weapons pose a threat to both troops and civilians. Remote detection of bioaerosols is important for timely deployment of effective countermeasures against these weapons and for triggering other detection systems. In this paper we describe a new approach for remote bioaerosol detection based on an eye-safe spectrally broadband backscatter LIDAR. This technique illuminates a remote cloud using a spectrally broadband laser centred about 1.5 ?m. The spectrally backscattered fraction of the broadband illumination beam is detected. Using an inverse Monte Carlo algorithm, the particle size distribution and refractive index of the cloud particles can be determined. In this way threat clouds containing anomalous man-made distributions of particles could be discriminated from normal background clouds. The laser is a custom designed source based on a special non-collinear optical parametric oscillator configuration. The laser produces Q-switched pulses with a maximum spectral bandwidth covering the 1.4 to 1.8 ?m region. In practice the spectral region of 1.52 to 1.75 ?m is used as this matches an atmospheric transmission window. A comparison of this broadband backscatter LIDAR technique, with the commonly used UV lidar fluorescence technique will be presented. Progress to date and details of a prototype LIDAR system will be described.

  17. Characterization of in vivo MRI detectable thalamic amyloid plaques from APP/PS1 mice

    International Nuclear Information System (INIS)

    Amyloid deposits are one of the hallmarks of Alzheimer's disease. Recent studies, in transgenic mice modeling Alzheimer's disease showed that, using in vivo, contrast agent-free, MRI, thalamic amyloid plaques are more easily detected than other plaques of the brain. Our study evaluated the characteristics of these thalamic plaques in a large population of APP/PS1, PS1 and C57BL/6 mice. Thalamic spots were detected in all mice but with different frequency and magnitude. Hence, the prevalence and size of the lesions were higher in APP/PS1 mice. However, even in APP/PS1 mice, thalamic spots did not occur in all the old animals. In APP/PS1 mice, spots detection was related to high iron and calcium load within amyloid plaques and thus reflects the ability of such plaque to capture large amounts of minerals. Interestingly, calcium and iron was also detected in extra-thalamic plaques but with a lower intensity. Hypointense lesions in the thalamus were not associated with the iron load in the tissue surrounding the plaques, nor with micro-hemorrhages, inflammation, or a neuro-degenerative context. (authors)

  18. Characterization of in vivo MRI detectable thalamic amyloid plaques from APP/PS1 mice

    Energy Technology Data Exchange (ETDEWEB)

    Dhenain, M. [URA CEA CNRS 2210, I2BM, SHFJ, 4 Place du General Leclerc, 91401 Orsay Cedex (France); Dhenain, M.; El Tannir El Tayara, N.; Wu, T.D.; Volk, A.; Quintana, C. [U759 INSERM, Centre Universitaire, Laboratoire 112, 91405 Orsay Cedex (France); Dhenain, M.; El Tannir El Tayara, N.; Wu, T.D.; Volk, A.; Quintana, C. [Institut Curie, Centre Universitaire, Laboratoire 112, 91405 Orsay Cedex (France); Guegan, M.; Delatour, B. [Instituto de Microelectronica de Madrid-CSIC, 8, Isaac Newton, 28760 Tres Cantos, Madrid (Spain)

    2009-07-01

    Amyloid deposits are one of the hallmarks of Alzheimer's disease. Recent studies, in transgenic mice modeling Alzheimer's disease showed that, using in vivo, contrast agent-free, MRI, thalamic amyloid plaques are more easily detected than other plaques of the brain. Our study evaluated the characteristics of these thalamic plaques in a large population of APP/PS1, PS1 and C57BL/6 mice. Thalamic spots were detected in all mice but with different frequency and magnitude. Hence, the prevalence and size of the lesions were higher in APP/PS1 mice. However, even in APP/PS1 mice, thalamic spots did not occur in all the old animals. In APP/PS1 mice, spots detection was related to high iron and calcium load within amyloid plaques and thus reflects the ability of such plaque to capture large amounts of minerals. Interestingly, calcium and iron was also detected in extra-thalamic plaques but with a lower intensity. Hypointense lesions in the thalamus were not associated with the iron load in the tissue surrounding the plaques, nor with micro-hemorrhages, inflammation, or a neuro-degenerative context. (authors)

  19. MnDPDP-enhanced MRI vs dual-phase spiral CT in the detection of hepatocellular carcinoma in cirrhosis

    International Nuclear Information System (INIS)

    The objectives of this study were twofold: (a) to assess safety and tolerability of the hepatobiliary MR contrast agent MnDPDP; and (b) to investigate the sensitivity of MnDPDP-enhanced MRI, in comparison with dual-phase spiral CT, in the detection of hepatocellular carcinoma (HCC) in cirrhosis. Fifty patients with liver cirrhosis and histologically proven HCC were enrolled in a prospective phase-IIIB clinical trial. All patients underwent evaluation with dual-phase spiral CT and pre-contrast and post-contrast MRI at 1.5 T. The MR examination protocol included spin-echo (SE) and gradient-recalled-echo (GRE) T1-weighted images acquired before and 60-120 min after administration of 0.5 ?mol/kg (0.5 ml/kg) MnDPDP (Teslascan, Nycomed Amersham, Oslo, Norway); and fast T2-weighted SE images obtained solely before contrast injection. Gold standard was provided by findings at Lipiodol CT in combination with follow-up spiral CT studies, which were repeated at 4-month intervals over a 10- to 27-month (mean ± SD 20.1 ± 5.1 months) follow-up period. No serious adverse event occurred. Eighty tumors ranging 0.8-9.1 cm in diameter (mean ± SD 3.2 ± 2.4 cm) were detected by Lipiodol CT or confirmed as cancerous foci by follow-up CT studies. Pre-contrast MRI detected 38 of 80 lesions (48 %); MnDPDP-enhanced MRI, 65 of 80 lesions (81 %); pre-contrast plus post-contrast MRI, 69 of 80 lesions (86 %); and dual-phase spiral CT, 64 of 80 lesions (80 %). The difference between unenhanced and MnDPDP-enhanced MRI was statistically significant (p < 0.001). The difference between MRI (pre-contrast plus post-contrast) and dual-phase spiral CT was not statistically significant (p = 0.33). The confidence in the final diagnosis, however, was significantly higher for MRI as compared with spiral CT (p < 0.001). MnDPDP is a safe and well-tolerated hepatobiliary MR contrast agent. Magnetic resonance imaging with use of MnDPDP is significantly more sensitive than unenhanced MRI and as good as dual-phase spiral CT for detection of HCC in cirrhosis. (orig.)

  20. Is MRI better than CT for detecting a vascular component to dementia? A systematic review and meta-analysis

    Directory of Open Access Journals (Sweden)

    Beynon Rebecca

    2012-06-01

    Full Text Available Abstract Background Identification of causes of dementia soon after symptom onset is important, because appropriate treatment of some causes of dementia can slow or halt its progression or enable symptomatic treatment where appropriate. The accuracy of MRI and CT, and whether MRI is superior to CT, in detecting a vascular component to dementia in autopsy confirmed and clinical cohorts of patients with VaD, combined AD and VaD (“mixed dementia”, and AD remain unclear. We conducted a systematic review and meta-analysis to investigate this question. Methods We searched eight databases and screened reference lists to identify studies addressing the review question. We assessed study quality using QUADAS. We estimated summary diagnostic accuracy according to imaging finding, and ratios of diagnostic odds ratios (RDORs for MRI versus CT and high versus low risk of bias. Results We included 7 autopsy and 31 non-autopsy studies. There was little evidence that selective patient enrolment and risk of incorporation bias impacted on diagnostic accuracy (p?=?0.12 to 0.95. The most widely reported imaging finding was white matter hyperintensities. For CT (11 studies summary sensitivity and specificity were 71% (95% CI 53%-85% and 55% (44%-66%. Corresponding figures for MRI (6 studies were 95% (87%-98% and 26% (12%-50%. General infarcts was the most specific imaging finding on MRI (96%; 95% CI 94%-97% and CT (96%; 93%-98%. However, sensitivity was low for both MRI (53%; 36%-70% and CT (52%; 22% to 80%. No imaging finding had consistently high sensitivity. Based on non-autopsy studies, MRI was more accurate than CT for six of seven imaging findings, but confidence intervals were wide. Conclusion There is insufficient evidence to suggest that MRI is superior to CT with respect to identifying cerebrovascular changes in autopsy-confirmed and clinical cohorts of VaD, AD, and ‘mixed dementia’.

  1. Goal-Directed Modulation of Neural Memory Patterns: Implications for fMRI-Based Memory Detection.

    Science.gov (United States)

    Uncapher, Melina R; Boyd-Meredith, J Tyler; Chow, Tiffany E; Rissman, Jesse; Wagner, Anthony D

    2015-06-01

    Remembering a past event elicits distributed neural patterns that can be distinguished from patterns elicited when encountering novel information. These differing patterns can be decoded with relatively high diagnostic accuracy for individual memories using multivoxel pattern analysis (MVPA) of fMRI data. Brain-based memory detection--if valid and reliable--would have clear utility beyond the domain of cognitive neuroscience, in the realm of law, marketing, and beyond. However, a significant boundary condition on memory decoding validity may be the deployment of "countermeasures": strategies used to mask memory signals. Here we tested the vulnerability of fMRI-based memory detection to countermeasures, using a paradigm that bears resemblance to eyewitness identification. Participants were scanned while performing two tasks on previously studied and novel faces: (1) a standard recognition memory task; and (2) a task wherein they attempted to conceal their true memory state. Univariate analyses revealed that participants were able to strategically modulate neural responses, averaged across trials, in regions implicated in memory retrieval, including the hippocampus and angular gyrus. Moreover, regions associated with goal-directed shifts of attention and thought substitution supported memory concealment, and those associated with memory generation supported novelty concealment. Critically, whereas MVPA enabled reliable classification of memory states when participants reported memory truthfully, the ability to decode memory on individual trials was compromised, even reversing, during attempts to conceal memory. Together, these findings demonstrate that strategic goal states can be deployed to mask memory-related neural patterns and foil memory decoding technology, placing a significant boundary condition on their real-world utility. PMID:26041920

  2. A new method for aircraft detection and orientation estimation in remote sensing

    Science.gov (United States)

    Fu, Yi; Yang, Weidong; Liu, Xiao

    2015-12-01

    Automatic targets recognition(ATR) of artificial objects in high resolution remote sensing images can be divided into two categories by the properties of targets. The first such building, a harbor which has fixed location and stable out looking. The other one, for example aircraft, whose location and posture is sensitive to the moment. Due to the variable sizes, colors, orientations, and complex background, aircraft detection is a difficult task in high resolution remote sensing images. In this paper, a simple and effective aircraft detection method with a single template is proposed, which exactly locates the object by outputting its geometric center, location and orientation. Compare to traditional method,this method only needs critical feature in the local areas of target and a binary template of aircraft. Compare to traditional Feature + Classifier method, it's easy, simple and don't need outline training,but also get high precision and low false rate in the same complicate background.

  3. Determination of Change Detection of Lanscape of the Kucuk Menderes Delta Using GIS and the Remote Sensing Techniques

    OpenAIRE

    Mustafa Bolca; Ünal Altinbas; Yusuf Kurucu; M. Tolga Esetlili

    2005-01-01

    Remote sensing and GIS offers an important means of detecting and analyzing temporal changes occurring in the earth surface. This research used remote sensing and GIS to quantify landscape changes at the Kucuk Menderes Basin, Izmir, Turkey. In this study, we concentrated on determining the geomorphology of the with time of the coastal strip and the coastal part of the Kucuk Menderes Basin towards terrestrial formation using aerial photographs and satellite images involving remote sensing tech...

  4. Ship-based detection of glyoxal over the remote tropical Pacific Ocean

    OpenAIRE

    Sinreich, R.; Coburn, S.; Dix, B.; Volkamer, R.

    2010-01-01

    We present the first detection of glyoxal (CHOCHO) over the remote tropical Pacific Ocean in the Marine Boundary Layer (MBL). The measurements were conducted by means of the University of Colorado Ship Multi-Axis Differential Optical Spectroscopy (CU SMAX-DOAS) instrument aboard the research vessel Ronald H. Brown. The research vessel was on a cruise in the framework of the VAMOS Ocean-Cloud-Atmosphere-Land Study – Regional Experiment (VOCALS-REx) and the Tropical Atmosphere Ocean (TAO) ...

  5. IQPC 2015 TRACK: WATER DETECTION AND CLASSIFICATION ON MULTISOURCE REMOTE SENSING AND TERRAIN DATA

    OpenAIRE

    A. Olasz; D. Kristóf; M. Belényesi; K. Bakos; Kovács, Z.; Balázs, B.; Sz. Szabó

    2015-01-01

    Since 2013, the EU FP7 research project “IQmulus” encourages the participation of the whole scientific community as well as specific user groups in the IQmulus Processing Contest (IQPC). This year, IQPC 2015 consists of three processing tasks (tracks), from which “Water detection and classification on multi-source remote sensing and terrain data” is introduced in the present paper. This processing track addresses a particular problem in the field of big data processing and management...

  6. Comparison of gadolinium-EOB-DTPA-enhanced and diffusion-weighted liver MRI for detection of small hepatic metastases

    Energy Technology Data Exchange (ETDEWEB)

    Shimada, Kotaro; Isoda, Hiroyoshi; Hirokawa, Yuusuke; Arizono, Shigeki; Shibata, Toshiya; Togashi, Kaori [Kyoto University Graduate School of Medicine, Department of Diagnostic Imaging and Nuclear Medicine, Kyoto (Japan)

    2010-11-15

    To compare the accuracy of gadolinium ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI with that of diffusion-weighted MRI (DWI) in the detection of small hepatic metastases (2 cm or smaller). Forty-five patients underwent abdominal MRI at 3 T, including T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), heavily T2WI (HASTE), DWI with a b-value of 500 s/mm{sup 2} and contrast-enhanced MRI with Gd-EOB-DTPA. Two groups were assigned and compared: group A (T1WI, T2WI, HASTE and contrast-enhanced study with Gd-EOB-DTPA), and group B (T1WI, T2WI, HASTE and DWI). Two observers independently interpreted the images obtained in a random order. For all hepatic metastases, the diagnostic performance using each imaging set was evaluated by receiver-operating characteristic (ROC) curve analysis. A total of 51 hepatic metastases were confirmed. The area under the ROC curve (Az) of group A was larger than that of group B, and the difference in the mean Az values between the two image sets was statistically significant, whereas, there were three metastases that lay near thin vessels or among multiple cysts and were better visualised in group B than in group A. Gd-EOB-DTPA-enhanced MRI showed higher accuracy in the detection of small metastases than DWI. (orig.)

  7. Does the degree of background enhancement in breast MRI affect the detection and staging of breast cancer?

    Energy Technology Data Exchange (ETDEWEB)

    Uematsu, Takayoshi [Shizuoka Cancer Center Hospital, Breast Imaging and Breast Intervention Section, Shizuoka (Japan); Kasami, Masako [Shizuoka Cancer Center Hospital, Department of Pathology, Naga-izumi, Shizuoka (Japan); Watanabe, Junichiro [Shizuoka Cancer Center Hospital, Division of Medical Oncology, Naga-izumi, Shizuoka (Japan)

    2011-11-15

    The purpose of this study was to assess the influence of background enhancement on the detection and staging of breast cancer using MRI as an adjunct to mammography or ultrasound. One hundred forty-six bilateral breast MRI examinations were evaluated to assess the extent of a known primary tumour and to problem solve after mammography or ultrasound without adjusting for the phase in the patients' menstrual cycle. The background enhancement was classified into four categories by visual evaluation: minimal, mild, moderate and marked. In total, 131 histologically confirmed abnormal cases (104 malignant and 27 benign) and 15 normal cases were included in the analysis. There was no tumour size-related bias between the groups (p = 0.522). For the primary index tumour, the sensitivities of MRI with minimal/mild and moderate/marked background enhancement were 100% and 76% (p = 0.001), respectively. Thus, the degree of background enhancement did not affect the specificity. For evaluating tumour extent (n = 104), the accuracy of MRI with moderate/marked background enhancement (52%) was significantly lower than that with minimal/mild background enhancement (84%; p = 0.002). The degree of background enhancement affected the detection and staging of breast cancer using MRI. (orig.)

  8. Experience acquired by the Mobile Remote-Control Operation and Detection Group of the CEA

    International Nuclear Information System (INIS)

    In recent years the Mobile Remote-Control Operation and Detection Group of the CEA have intervened on various occasions as follows: to replace personnel required to spend time in working areas in which dose rates were permanently high or very high; to support personnel required to work near high-activity sources producing or likely to produce mobile or short-lived beams of ionizing radiation; and to support personnel required to perform tedious and/or repetitive operations in working areas in which only a limited amount of time may be spent. Among the interventions performed, mention is made of the recovery of radioactive sources which have been placed in abnormal positions as a result of incorrect handling or incidents involving machinery; the transfer of radioactive sources during the loading or unloading of irradiation devices; the inspection by television camera, modification, dismantling or reassembly of protective devices in the neighbourhood of high- or very high-activity sources; and the cleaning of installations polluted by radioactive contaminants which present a high risk of external irradiation of the personnel required to work there. After obtaining a hermetically sealed version of the ''Mobile Remote-Control Intervention Operator'' (TOMI) and an ''Intervention Dose and Dose-Rate Measurement Unit'' (EDDI) in 1979, the Mobile Remote-Control Operation and Detection Group has very recently put into operation a remote-controlled intervention module which takes up very little space and can carry over 100 kg of different types of equipment. The authors summarize development work on the MERITE module and on master-slave remote handling devices with servo control and feedback of the MA-23 type, the flexibility of which has yet again been verified very recently during an intervention at a nuclear installation. (author)

  9. An Optimized Clustering Approach for Automated Detection of White Matter Lesions in MRI Brain Images

    Directory of Open Access Journals (Sweden)

    M. Anitha

    2012-04-01

    Full Text Available Settings White Matter lesions (WMLs are small areas of dead cells found in parts of the brain. In general, it is difficult for medical experts to accurately quantify the WMLs due to decreased contrast between White Matter (WM and Grey Matter (GM. The aim of this paper is to
    automatically detect the White Matter Lesions which is present in the brains of elderly people. WML detection process includes the following stages: 1. Image preprocessing, 2. Clustering (Fuzzy c-means clustering, Geostatistical Possibilistic clustering and Geostatistical Fuzzy clustering and 3.Optimization using Particle Swarm Optimization (PSO. The proposed system is tested on a database of 208 MRI images. GFCM yields high sensitivity of 89%, specificity of 94% and overall accuracy of 93% over FCM and GPC. The clustered brain images are then subjected to Particle Swarm Optimization (PSO. The optimized result obtained from GFCM-PSO provides sensitivity of 90%, specificity of 94% and accuracy of 95%. The detection results reveals that GFCM and GFCMPSO better localizes the large regions of lesions and gives less false positive rate when compared to GPC and GPC-PSO which captures the largest loads of WMLs only in the upper ventral horns of the brain.

  10. Using High Spatial Resolution to Improve BOLD fMRI Detection at 3T

    Science.gov (United States)

    Claise, Béatrice; Jean, Betty

    2015-01-01

    For different functional magnetic resonance imaging experiments using blood oxygenation level-dependent (BOLD) contrast, the acquisition of T2*-weighted scans at a high spatial resolution may be advantageous in terms of time-course signal-to-noise ratio and of BOLD sensitivity when the regions are prone to susceptibility artifacts. In this study, we explore this solution by examining how spatial resolution influences activations elicited when appetizing food pictures are viewed. Twenty subjects were imaged at 3 T with two different voxel volumes, 3.4 ?l and 27 ?l. Despite the diminution of brain coverage, we found that high-resolution acquisition led to a better detection of activations. Though known to suffer to different degrees from susceptibility artifacts, the activations detected by high spatial resolution were notably consistent with those reported in published activation likelihood estimation meta-analyses, corresponding to taste-responsive regions. Furthermore, these regions were found activated bilaterally, in contrast with previous findings. Both the reduction of partial volume effect, which improves BOLD contrast, and the mitigation of susceptibility artifact, which boosts the signal to noise ratio in certain regions, explained the better detection noted with high resolution. The present study provides further evidences that high spatial resolution is a valuable solution for human BOLD fMRI, especially for studying food-related stimuli. PMID:26550990

  11. Remote detection of nuclear magnetic resonance with an anisotropic magnetoresistive sensor

    Science.gov (United States)

    Verpillat, F.; Ledbetter, M. P.; Xu, S.; Michalak, D. J.; Hilty, C.; Bouchard, L.-S.; Antonijevic, S.; Budker, D.; Pines, A.

    2008-01-01

    We report the detection of nuclear magnetic resonance (NMR) using an anisotropic magnetoresistive (AMR) sensor. A “remote-detection” arrangement was used in which protons in flowing water were prepolarized in the field of a superconducting NMR magnet, adiabatically inverted, and subsequently detected with an AMR sensor situated downstream from the magnet and the adiabatic inverter. AMR sensing is well suited for NMR detection in microfluidic “lab-on-a-chip” applications because the sensors are small, typically on the order of 10 ?m. An estimate of the sensitivity for an optimized system indicates that ?6 × 1013 protons in a volume of 1,000 ?m3, prepolarized in a 10-kG magnetic field, can be detected with a signal-to-noise ratio of 3 in a 1-Hz bandwidth. This level of sensitivity is competitive with that demonstrated by microcoils in superconducting magnets and with the projected sensitivity of microfabricated atomic magnetometers. PMID:18268323

  12. New radiological material detection technologies for nuclear forensics: Remote optical imaging and graphene-based sensors.

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, Richard Karl [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Martin, Jeffrey B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wiemann, Dora K. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Choi, Junoh [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Howell, Stephen W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    We developed new detector technologies to identify the presence of radioactive materials for nuclear forensics applications. First, we investigated an optical radiation detection technique based on imaging nitrogen fluorescence excited by ionizing radiation. We demonstrated optical detection in air under indoor and outdoor conditions for alpha particles and gamma radiation at distances up to 75 meters. We also contributed to the development of next generation systems and concepts that could enable remote detection at distances greater than 1 km, and originated a concept that could enable daytime operation of the technique. A second area of research was the development of room-temperature graphene-based sensors for radiation detection and measurement. In this project, we observed tunable optical and charged particle detection, and developed improved devices. With further development, the advancements described in this report could enable new capabilities for nuclear forensics applications.

  13. Real-time remote detection and measurement for airborne imaging spectroscopy: a case study with methane

    Science.gov (United States)

    Thompson, D. R.; Leifer, I.; Bovensmann, H.; Eastwood, M.; Fladeland, M.; Frankenberg, C.; Gerilowski, K.; Green, R. O.; Kratwurst, S.; Krings, T.; Luna, B.; Thorpe, A. K.

    2015-10-01

    Localized anthropogenic sources of atmospheric CH4 are highly uncertain and temporally variable. Airborne remote measurement is an effective method to detect and quantify these emissions. In a campaign context, the science yield can be dramatically increased by real-time retrievals that allow operators to coordinate multiple measurements of the most active areas. This can improve science outcomes for both single- and multiple-platform missions. We describe a case study of the NASA/ESA CO2 and MEthane eXperiment (COMEX) campaign in California during June and August/September 2014. COMEX was a multi-platform campaign to measure CH4 plumes released from anthropogenic sources including oil and gas infrastructure. We discuss principles for real-time spectral signature detection and measurement, and report performance on the NASA Next Generation Airborne Visible Infrared Spectrometer (AVIRIS-NG). AVIRIS-NG successfully detected CH4 plumes in real-time at Gb s-1 data rates, characterizing fugitive releases in concert with other in situ and remote instruments. The teams used these real-time CH4 detections to coordinate measurements across multiple platforms, including airborne in situ, airborne non-imaging remote sensing, and ground-based in situ instruments. To our knowledge this is the first reported use of real-time trace-gas signature detection in an airborne science campaign, and presages many future applications. Post-analysis demonstrates matched filter methods providing noise-equivalent (1?) detection sensitivity for 1.0 % CH4 column enhancements equal to 141 ppm m.

  14. Capabilities of Remote Sensing Hyperspectral Images for the Detection of Lead Contamination: a Review

    Science.gov (United States)

    Maliki, A. A.; Owens, G.; Bruce, D.

    2012-07-01

    Advances in remote sensing technologies are increasingly becoming more useful for resource, ecosystem and agricultural management applications to the extent that these techniques can now also be applied for monitoring of soil contamination and human health risk assessment. While, extensive previous studies have shown that Visible and Near Infrared Spectroscopy (VNIRS) in the spectral range 400-2500 nm can be used to quantify various soil constituents simultaneously, the direct determination of metal concentrations by remote sensing and reflectance spectroscopy is not as well examined as other soil parameters. The application of VNIRS, including laboratory hyperpectral measurements, field spectrometer measurements or image spectroscopy, generally achieves a good prediction of metal concentrations when compared to traditional wet chemical methods and has the advantage of being relatively less expensive and faster, allowing chemical assessment of contamination in close to real time. Furthermore, imaging spectroscopy can potentially provide significantly more samples over a larger spatial extent than traditional ground sampling methods. Thus the development of remote sensing techniques (field based and either airborne or satellite hyperspectral imaging) can support the monitoring and efficient mapping of metal contamination (in dust and soil) for environmental and health impact assessment. This review is concerned with the application of remote sensing and reflectance spectroscopy to the detection of heavy metals and discusses how current methods could be applied for the quantification of Pb contaminated soil surrounding mines and smelters.

  15. CAPABILITIES OF REMOTE SENSING HYPERSPECTRAL IMAGES FOR THE DETECTION OF LEAD CONTAMINATION: A REVIEW

    Directory of Open Access Journals (Sweden)

    A. A. Maliki

    2012-07-01

    Full Text Available Advances in remote sensing technologies are increasingly becoming more useful for resource, ecosystem and agricultural management applications to the extent that these techniques can now also be applied for monitoring of soil contamination and human health risk assessment. While, extensive previous studies have shown that Visible and Near Infrared Spectroscopy (VNIRS in the spectral range 400–2500 nm can be used to quantify various soil constituents simultaneously, the direct determination of metal concentrations by remote sensing and reflectance spectroscopy is not as well examined as other soil parameters. The application of VNIRS, including laboratory hyperpectral measurements, field spectrometer measurements or image spectroscopy, generally achieves a good prediction of metal concentrations when compared to traditional wet chemical methods and has the advantage of being relatively less expensive and faster, allowing chemical assessment of contamination in close to real time. Furthermore, imaging spectroscopy can potentially provide significantly more samples over a larger spatial extent than traditional ground sampling methods. Thus the development of remote sensing techniques (field based and either airborne or satellite hyperspectral imaging can support the monitoring and efficient mapping of metal contamination (in dust and soil for environmental and health impact assessment. This review is concerned with the application of remote sensing and reflectance spectroscopy to the detection of heavy metals and discusses how current methods could be applied for the quantification of Pb contaminated soil surrounding mines and smelters.

  16. MOVING OBSTACLE DETECTION AND REMOTE VIDEO MONITORING SYSTEM USING CORTEX-A8

    OpenAIRE

    V.PADMAJA, KAVITHA MAMINDLA

    2013-01-01

    In this paper the Detection of Moving obstacle and remote video monitoring and extracting the key frames from the captured video system based on high performance SAMSUNG S5PV210 CORTEX-A8 processor core is build and expanding peripheral devices using embedded Linux as the operating system. Today monitoring systems are either webcam based or simple motion detection based. Here we have interfaced both webcam and PIR sensor to the embedded system so that the user can get an immediate alert messa...

  17. Remote Optical Detection of the Fusion State in Laser Deep Penetration Welding

    Science.gov (United States)

    Tenner, F.; Brock, C.; Hohenstein, R.; Zalevsky, Z.; Schmidt, M.

    We introduce a novel technique for the determination of the fusion state of laser welded blind joints (e.g. overlap joints) by measuring the vibrations of the workpiece during the welding process. In case of incomplete fusion, the workpiece vibrations differ significantly from the vibrations observed during a sound weld. The detection of the vibrations is performed by observing a speckle pattern on the workpiece surface. The movement of this pattern allows remote detection of the workpiece oscillations close to the keyhole. Those oscillations contain information on the fusion state of the weld.

  18. Ship Detection of Remote Sensing Image on FRHT and Multi-Points Curvature Based Polygon Approximation

    Directory of Open Access Journals (Sweden)

    Wang Luo

    2012-08-01

    Full Text Available One of the most difficult tasks of ship detection is detecting the ship which is docking at the port in remote sensing image. Traditional methods of automatic detection cannot be used to detect the land/waterboundaries, because both the gray values and textural features of a port are similar to those of the ships which are docking at the port. Therefore, ships cannot be accurately detected in this case. In this study, a novel method of land/water-boundaries detection is proposed, which is based on a polygon approximation method by incorporating two techniques, i.e., Fuzzy Randomized Hough Transform (FRHT and Multi-Points Curvature (MPC. The method considered the feature of human vision that the straight-line of the land/water-boundaries can be detected more accurately and rapidly. With the detection result of land/water-boundaries, ships docking at the port can be accurately detected. The experiment results demonstrate that this method can achieve good result of ship detection.

  19. Detecting functional connectivity change points for single-subject fMRI data

    Directory of Open Access Journals (Sweden)

    Ivor Cribben

    2013-10-01

    Full Text Available Recently in functional magnetic resonance imaging (fMRI studies there has been an increased interest in understanding the dynamic manner in which brain regions communicate with one another, as subjects perform a set of experimental tasks or as their psychological state changes. Dynamic Connectivity Regression (DCR is a data-driven technique used for detecting temporal change points in functional connectivity between brain regions where the number and location of the change points are unknown a priori. After finding the change points, DCR estimates a graph or set of relationships between the brain regions for data that falls between pairs of change points. In previous work, the method was predominantly validated using multi-subject data. In this paper, we concentrate on single-subject data and introduce a new DCR algorithm. The new algorithm increases accuracy for individual subject data with a small number of observations and reduces the number of false positives in the estimated undirected graphs. We also introduce a new Likelihood Ratio test for comparing sparse graphs across (or within subjects; thus allowing us to determine whether data should be combined across subjects. We perform an extensive simulation analysis on vector autoregression (VAR data as well as to an fMRI data set from a study (n=23 of a state anxiety induction using a socially evaluative threat challenge. The focus on single-subject data allows us to study the variation between individuals and may provide us with a deeper knowledge of the workings of the brain.

  20. Introducing a new definition towards clinical detection of Microvascular changes using diffusion and perfusion MRI

    International Nuclear Information System (INIS)

    Based on MRI diffusion's and perfusion, a new criterion for detection and the healing progress of damaged tissue is suggested. The study is based on the ratio of capillary radii in symmetrical damaged and normal tissue neighboring spaces. The apparent diffusion coefficient and cerebral blood flow were measured in the brain tissues of six male wistar rats utilizing suggested MRI measurement techniques. The apparent diffusion coefficient values of damaged and normal regions were (392±34.1) x10-6 mm2s-1 and (659±40.7)x10-6 mm2s-1, respectively. The cerebral blood flow values of damaged and normal regions were 14.5±10.13 mi/min/100 g and 125±41.03 mi/min/100 g, respectively. The geometrical parameters of the capillary for damaged and normal regions midle root/? ?, where midle root is the mean radius and ? is the mean capillary segment length , were calculated to be 5.45±2.01mm0.5g-0.5 (mean±Sd) and 12.8±2.04 mm0.5g-0.5, respectively. Furthermore, based on constant ?, the damaged, versus normal region, mean radius, was shown to follow the criterionmidle root Damaged?0.13xmidle root Normal. A further analysis was conducted through suitable theoretical modeling and assumptions for the above-mentioned criterion. The analysis showed a distinct difference between normal and damaged tissues in various healing progress conditions. Moreover, a new image, namely, Diffusion/Flow map (DF map), which is a mere division of the ADC map to the cerebral blood flow map, was introduced and utilized to contrast between normal and damaged tissue

  1. Prostate cancer transrectal HIFU ablation: detection of local recurrences using T2-weighted and dynamic contrast-enhanced MRI

    International Nuclear Information System (INIS)

    The objective was to evaluate T2-weighted (T2w) and dynamic contrast-enhanced (DCE) MRI in detecting local cancer recurrences after prostate high-intensity focused ultrasound (HIFU) ablation. Fifty-nine patients with biochemical recurrence after prostate HIFU ablation underwent T2-weighted and DCE MRI before transrectal biopsy. For each patient, biopsies were performed by two operators: operator 1 (blinded to MR results) performed random and colour Doppler-guided biopsies (''routine biopsies''); operator 2 obtained up to three cores per suspicious lesion on MRI (''targeted biopsies''). Seventy-seven suspicious lesions were detected on DCE images (n=52), T2w images (n=2) or both (n=23). Forty patients and 41 MR lesions were positive at biopsy. Of the 36 remaining MR lesions, 20 contained viable benign glands. Targeted biopsy detected more cancers than routine biopsy (36 versus 27 patients, p=0.0523). The mean percentages of positive cores per patient and of tumour invasion of the cores were significantly higher for targeted biopsies (p<0.0001). The odds ratios of the probability of finding viable cancer and viable prostate tissue (benign or malignant) at targeted versus routine biopsy were respectively 3.35 (95% CI 3.05-3.64) and 1.38 (95% CI 1.13-1.63). MRI combining T2-weighted and DCE images is a promising method for guiding post-HIFU biopsy towards areas containing recurrent cancer and viable prostate tissue. (orig.)

  2. Specific detection and imaging of enzyme activity by signal-amplifiable self-assembling (19)F MRI probes.

    Science.gov (United States)

    Matsuo, Kazuya; Kamada, Rui; Mizusawa, Keigo; Imai, Hirohiko; Takayama, Yuki; Narazaki, Michiko; Matsuda, Tetsuya; Takaoka, Yousuke; Hamachi, Itaru

    2013-09-16

    Specific turn-on detection of enzyme activities is of fundamental importance in drug discovery research, as well as medical diagnostics. Although magnetic resonance imaging (MRI) is one of the most powerful techniques for noninvasive visualization of enzyme activity, both in vivo and ex vivo, promising strategies for imaging specific enzymes with high contrast have been very limited to date. We report herein a novel signal-amplifiable self-assembling (19) F?NMR/MRI probe for turn-on detection and imaging of specific enzymatic activity. In NMR spectroscopy, these designed probes are "silent" when aggregated, but exhibit a disassembly driven turn-on signal change upon cleavage of the substrate part by the catalytic enzyme. Using these (19) F probes, nanomolar levels of two different target enzymes, nitroreductase (NTR) and matrix metalloproteinase (MMP), could be detected and visualized by (19) F?NMR spectroscopy and MRI. Furthermore, we have succeeded in imaging the activity of endogenously secreted MMP in cultured media of tumor cells by (19) F?MRI, depending on the cell lines and the cellular conditions. These results clearly demonstrate that our turn-on (19) F probes may serve as a screening platform for the activity of MMPs. PMID:23955524

  3. Detection of extranodal spread in head and neck cancer with [18F]FDG PET and MRI: improved accuracy?

    International Nuclear Information System (INIS)

    Preoperative detection of extranodal spread (ENS) in head and neck cancer can have important consequences for patient management. The aim of this study was to determine whether 18-fluorodeoxyglucose positron emission tomography ([18F]FDG PET) or a combination with Magnetic Resonance Imaging (MRI) could more accurately predict ENS, especially with the near availability of fully integrated [18F]FDG PET/MRI scanners. In retrospective cohort design a total of twelve patients, with 18 lymphnode metastases were studied with [18F]FDG PET and MRI. Presence of ENS was scored on MRI, and [18F]FDG PET images using a SUV max cut-off point of 12. Histopathology results were used as reference standard. Sensitivity, specificity and accuracy were calculated. The sensitivity, specificity and accuracy of [18F]FDG PET for ENS reached 70%,100% and 83%, respectively. The mean SUVmax of ENS positive lymphnodes was 13.6 versus 8.7 for lymphnode metastases without ENS (P=0.03). The sensitivity, specificity and accuracy of MRI for ENS were 70%, 100% and 83%, respectively. When the [18F]FDG PET and MRI findings were combined sensitivity, specificity and accuracy were 80%, 100% and 89%, respectively. Thus, accuracy increased from 83% to 89%. When there is no ENS or doubt of ENS on MRI, [18F]FDG PET seems to have additional value since it improves sensitivity and resolves uncertainty in case of high FDG uptake. This benefit needs to be confirmed prospectively in a larger cohort.

  4. Iqpc 2015 Track: Water Detection and Classification on Multisource Remote Sensing and Terrain Data

    Science.gov (United States)

    Olasz, A.; Kristóf, D.; Belényesi, M.; Bakos, K.; Kovács, Z.; Balázs, B.; Szabó, Sz.

    2015-08-01

    Since 2013, the EU FP7 research project "IQmulus" encourages the participation of the whole scientific community as well as specific user groups in the IQmulus Processing Contest (IQPC). This year, IQPC 2015 consists of three processing tasks (tracks), from which "Water detection and classification on multi-source remote sensing and terrain data" is introduced in the present paper. This processing track addresses a particular problem in the field of big data processing and management with the objective of simulating a realistic remote sensing application scenario. The main focus is on the detection of water surfaces (natural waters, flood, inland excess water, other water-affected categories) using remotely sensed data. Multiple independent data sources are available and different tools could be used for data processing and evaluation. The main challenge is to identify the right combination of data and methods to solve the problem in the most efficient way. Although the first deadline for submitting track solutions has passed and the track has been successfully concluded, the track organizers decided to keep the possibility of result submission open to enable collecting a variety of approaches and solutions for this interesting problem.

  5. Efficacy Evaluation of Different Wavelet Feature Extraction Methods on Brain MRI Tumor Detection

    Science.gov (United States)

    Nabizadeh, Nooshin; John, Nigel; Kubat, Miroslav

    2014-03-01

    Automated Magnetic Resonance Imaging brain tumor detection and segmentation is a challenging task. Among different available methods, feature-based methods are very dominant. While many feature extraction techniques have been employed, it is still not quite clear which of feature extraction methods should be preferred. To help improve the situation, we present the results of a study in which we evaluate the efficiency of using different wavelet transform features extraction methods in brain MRI abnormality detection. Applying T1-weighted brain image, Discrete Wavelet Transform (DWT), Discrete Wavelet Packet Transform (DWPT), Dual Tree Complex Wavelet Transform (DTCWT), and Complex Morlet Wavelet Transform (CMWT) methods are applied to construct the feature pool. Three various classifiers as Support Vector Machine, K Nearest Neighborhood, and Sparse Representation-Based Classifier are applied and compared for classifying the selected features. The results show that DTCWT and CMWT features classified with SVM, result in the highest classification accuracy, proving of capability of wavelet transform features to be informative in this application.

  6. Optimization of Visual Tasks for Detecting Visual Cortex Activity in fMRI Studies

    Directory of Open Access Journals (Sweden)

    "A. Mirzajani

    2005-08-01

    Full Text Available Introduction: functional magnetic resonance imaging is a useful non-invasive technique for the evaluation and mapping of human brain, especially the visual cortex. One of the most important subjects in this background is optimizing visual stimuli in various forms of visual tasks for acquiring significant and ro-bust signals. Materials and methods: The effects of physical pa-rameters of visual stimuli on 14 healthy volunteers for detecting visual cortical activity were evaluated by functional magnetic resonance imaging. These pa-rameters were temporal frequency (TF, different pat-terns of activation including, square wave and sine wave grating, and two different states of rest includ-ing black and white screens. Results: The results showed that BOLD signal will be maximally in the TF of 8 Hz, and use the black screen in the rest state. However there was not significant difference between square-¬wave and sine-wave grat-ings in producing visual activation in the cortex. Conclusion: Physical parameters of visual tasks are effective in detecting visual cortical activity, and it is necessary to pay attention to them in order to get sig-nificant and robust signal. Visual tasks with TF of 8 Hz and one pattern of square-wave or sine-wave in activation state, and black screen in rest state are op-timally suitable for fMRI studies.

  7. Diagnostic performance of combined cardiac MRI for detection of coronary artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Andrade Fernandes de Mello, Ricardo, E-mail: ricardoafmello@gmail.com [Hospital de Clinicas de Niteroi - HCN, Niteroi, RJ (Brazil); Radiology Department, Universidade Federal do Rio de Janeiro - UFRJ, Rio de Janeiro, RJ (Brazil); Universidade Federal do Espirito Santo - UFES, Vitroria, ES (Brazil); Nacif, Marcelo Souto, E-mail: msnacif@gmail.com [Hospital de Clinicas de Niteroi - HCN, Niteroi, RJ (Brazil); Radiology Department, Universidade Federal do Rio de Janeiro - UFRJ, Rio de Janeiro, RJ (Brazil); Radiology and Imaging Sciences, National Institutes of Health Clinical Center, Bethesda, MD (United States); Radiology Department, Universidade Federal Fluminense - UFF, Niteroi, RJ (Brazil); Sarmet dos Santos, Alair Augusto Sarmet, E-mail: alairsarmet@globo.com [Hospital de Clinicas de Niteroi - HCN, Niteroi, RJ (Brazil); Radiology Department, Universidade Federal Fluminense - UFF, Niteroi, RJ (Brazil); Cury, Ricardo Caldeira, E-mail: RCury@baptisthealth.net [Baptist Cardiac and Vascular Institute, Miami, FL (United States); Rochitte, Carlos Eduardo, E-mail: rochitte@incor.usp.br [Department of Cardiovascular MRI and CT InCor - HCFMUSP, SP (Brazil); Marchiori, Edson, E-mail: edmarchiori@gmail.com [Radiology Department, Universidade Federal do Rio de Janeiro - UFRJ, Rio de Janeiro, RJ (Brazil); Radiology Department, Universidade Federal Fluminense - UFF, Niteroi, RJ (Brazil)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer In this study, we evaluated the accuracy of a Combined CMR protocol in the detection of significant CAD. Black-Right-Pointing-Pointer The invasive coronary angiography was the reference standard. Black-Right-Pointing-Pointer Results obtained in our study indicate that combination of perfusion and cine-MR during stress/rest, associated to delayed enhancement in the same protocol improves CMRI diagnostic accuracy and sensitivity for patients with significant coronary stenosis. Black-Right-Pointing-Pointer The Combined CMR protocol may therefore be helpful for risk stratification and defining treatment strategies. -- Abstract: Objective: To evaluate the diagnostic performance of stress perfusion cardiac MR (CMR) for detecting significant CAD ({>=}70% narrowing) in comparison with invasive coronary angiography (ICA) as a reference standard. Methods: Examinations of 54 patients who underwent both stress perfusion CMR and ICA for investigation of CAD between 2007 and 2009 were evaluated. The CMR protocol included dipyridamole stress and rest perfusion, stress and rest cine MRI for assessment of ventricular function and delayed gadolinium enhancement for assessment of myocardial viability and detection of infarction. CMR interpretation was performed by 2 observers blinded to the results of ICA and the clinical history. Results: From a total of 54 patients, 37 (68.5%) showed significant CAD in 71 coronary territories. A perfusion defect was detected in 35 patients and in 69 coronary territories. Individual stress perfusion CMR evaluation showed the highest accuracy (83%) of the CMR techniques. The combined analysis using all sequences increased the overall accuracy of CMR to 87%. Conclusion: Combination of perfusion and cine-MR during stress/rest, associated to delayed enhancement in the same protocol improves CMRI diagnostic accuracy and sensitivity for patients with significant coronary stenosis, and may therefore be helpful for risk stratification and defining treatment strategies.

  8. Diagnostic performance of combined cardiac MRI for detection of coronary artery disease

    International Nuclear Information System (INIS)

    Highlights: ? In this study, we evaluated the accuracy of a Combined CMR protocol in the detection of significant CAD. ? The invasive coronary angiography was the reference standard. ? Results obtained in our study indicate that combination of perfusion and cine-MR during stress/rest, associated to delayed enhancement in the same protocol improves CMRI diagnostic accuracy and sensitivity for patients with significant coronary stenosis. ? The Combined CMR protocol may therefore be helpful for risk stratification and defining treatment strategies. -- Abstract: Objective: To evaluate the diagnostic performance of stress perfusion cardiac MR (CMR) for detecting significant CAD (?70% narrowing) in comparison with invasive coronary angiography (ICA) as a reference standard. Methods: Examinations of 54 patients who underwent both stress perfusion CMR and ICA for investigation of CAD between 2007 and 2009 were evaluated. The CMR protocol included dipyridamole stress and rest perfusion, stress and rest cine MRI for assessment of ventricular function and delayed gadolinium enhancement for assessment of myocardial viability and detection of infarction. CMR interpretation was performed by 2 observers blinded to the results of ICA and the clinical history. Results: From a total of 54 patients, 37 (68.5%) showed significant CAD in 71 coronary territories. A perfusion defect was detected in 35 patients and in 69 coronary territories. Individual stress perfusion CMR evaluation showed the highest accuracy (83%) of the CMR techniques. The combined analysis using all sequences increased the overall accuracy of CMR to 87%. Conclusion: Combination of perfusion and cine-MR during stress/rest, associated to delayed enhancement in the same protocol improves CMRI diagnostic accuracy and sensitivity for patients with significant coronary stenosis, and may therefore be helpful for risk stratification and defining treatment strategies.

  9. Remote ischemic perconditioning in thrombolysed stroke patients : Randomized study of activating endogenous neuroprotection - design and MRI measurements

    DEFF Research Database (Denmark)

    Hougaard, K D; Hjort, N

    2013-01-01

    BACKGROUND: Intravenous administration of alteplase is the only approved treatment for acute ischemic stroke. Despite the effectiveness of this treatment, 50% of patients suffer chronic neurological disability, which may in part be caused by ischemia-reperfusion injury. Remote ischemic perconditioning, performed as a transient ischemic stimulus by blood-pressure cuff inflation to an extremity, has proven effective in attenuating ischemia-reperfusion injury in animal models of stroke. Remote ischemic perconditioning increases myocardial salvage in patients undergoing acute revascularization for acute myocardial infarction. To clarify whether a similar benefit can be obtained in patients undergoing thrombolysis for acute stroke, we included patients from June 2009 to January 2011. AIM AND DESIGN: The aims of the study are: to estimate the effect of remote ischemic perconditioning as adjunctive therapy to intravenous alteplase of acute ischemic stroke within the 4-h time window and to investigate the feasibilityof remote ischemic perconditioning performed during transport to hospital in patients displaying symptoms of acute stroke. Patients are randomized to remote ischemic perconditioning in a single-blinded fashion during transportation to hospital. Only patients with magnetic resonance imaging-proven ischemic stroke, who subsequently are treated with intravenous alteplase, and in selected cases additional endovascular treatment, are finally included in the study. STUDY OUTCOMES: Primary end-point is penumbral salvage. Penumbra is defined as hypoperfused yet viable tissue identified as the mismatch between perfusion-weighted imaging and diffusion-weighted imaging lesion on magnetic resonance imaging scans. Primary outcome is a mismatch volume not progressing to infarction on one-month follow-up T2 fluid attenuated inversion recovery. Secondary end-points include: infarct growth (expansion of the diffusion-weighted imaging lesion) from baseline to the 24-h and one-month follow-up examination. Infarct growth insideand outside the acute perfusion-weighted imaging-diffusion-weighted imaging mismatch zone is quantified by use of coregistration. Clinical outcome after three-months. The influence of physical activity (Physical Activity Scale for the Elderly score) on effect of remote ischemic perconditioning. Feasibility of remote ischemic perconditioning in acute stroke patients. SUMMARY: This phase 3 trial is the first study in patients with acute ischemic stroke to evaluate the effect size of remote ischemic perconditioning as a pretreatment to intravenous alteplase, measured as penumbral salvage on multimodal magnetic resonance imaging and clinical outcome after three-months follow-up.

  10. Role of MRI for detection and characterization of pulmonary nodules; Rolle der MRT zur Detektion und Abklaerung pulmonaler Rundherde

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, G. [Universitaetsspital Basel, Klinik fuer Radiologie und Nuklearmedizin, Basel (Switzerland); Koenigkam-Santos, M. [University Hospital of the School of Medicine of Ribeirao Preto - University of Sao Paulo, Department of Radiology, Ribeirao Preto, Sao Paulo (Brazil); Biederer, J. [Universitaetsklinikum Heidelberg, Diagnostische und Interventionelle Radiologie, Heidelberg (Germany); Puderbach, M. [Hufeland-Klinikum GmbH, Abteilung fuer Diagnostische und Interventionelle Radiologie, Bad Langensalza (Germany)

    2014-05-15

    Due to physical and technical limitations, magnetic resonance imaging (MRI) has hitherto played only a minor role in image-based diagnostics of the lungs. However, as a consequence of important methodological developments during recent years, MRI has developed into a technically mature and clinically well-proven method for specific pulmonary questions. The purpose of this article is to provide an overview on the currently available sequences and techniques for assessment of pulmonary nodules and analyzes the clinical significance according to the current literature. The main focus is on the detection of lung metastases, the detection of primary pulmonary malignancies in high-risk individuals and the differentiation between pulmonary nodules of benign and malignant character. The MRI technique has a sensitivity of approximately 80 % for detection of malignant pulmonary nodules compared to the reference standard low-dose computed tomography (CT) and is thus somewhat inferior to CT. Advantages of MRI on the other hand are a higher specificity in differentiating malignant and benign pulmonary nodules and the absence of ionizing radiation exposure. A systematic use of MRI as a primary tool for detection and characterization of pulmonary nodules is currently not recommended due to insufficient data. The diagnostic potential of MRI for early detection and staging of malignant pulmonary diseases, however, seems promising. Therefore, further evaluation of MRI as a secondary imaging modality in clinical trials is highly warranted. (orig.) [German] Mit den technischen Weiterentwicklungen in den vergangenen Jahren hat sich die MRT zu einem methodisch ausgereiften und fuer spezifische pulmonale Fragestellungen bereits auch klinisch bewaehrten Untersuchungsverfahren entwickelt. Ohne Strahlenexposition kombiniert sie morphologische und funktionelle Diagnostik und ergaenzt das Spektrum der etablierten Verfahren fuer die bildgebende Diagnostik der Lunge. Diese Arbeit gibt einen Ueberblick ueber die aktuell verwendeten Sequenzen und Techniken zur Darstellung pulmonaler Rundherde und analysiert deren klinischen Stellenwert anhand der aktuellen Studienlage. In Zentrum stehen dabei die Detektion pulmonaler Metastasen, die Detektion primaer pulmonaler Malignome bei Personen mit Risikoprofil und die Abklaerung pulmonaler Rundherde hinsichtlich ihrer Dignitaet. Die MRT besitzt im Vergleich zum Referenzstandard Niedrigdosis-CT eine Sensitivitaet von ca. 80 % fuer die Detektion maligner pulmonaler Rundherde und ist der CT damit etwas unterlegen. Vorteile der MRT gegenueber der Niedrigdosis-CT sind andererseits die hoehere Spezifitaet bei der Differenzierung maligner und benigner pulmonaler Rundherde sowie die fehlende Strahlenexposition. Ausserhalb von Studien kann ein breiter Einsatz der MRT als Screeningverfahren zur Detektion und Abklaerung pulmonaler Rundherde aufgrund der noch ungenuegenden Datenlage derzeit noch nicht empfohlen werden. Das diagnostische Potenzial der MRT fuer die Frueherkennung und das Staging pulmonaler Malignome rechtfertigt aber die weitere Evaluation der MRT als sekundaere Modalitaet im Rahmen von Studien. (orig.)

  11. 'One-stop-shop' staging: Should we prefer FDG-PET/CT or MRI for the detection of bone metastases?

    International Nuclear Information System (INIS)

    Aim: The aim of this study was to compare the diagnostic accuracy of fully diagnostic, contrast-enhanced whole-body FDG-PET/CT and whole-body MRI for detection of bone metastases in patients suffering from newly diagnosed non-small cell lung cancer and malignant melanoma. Material and Methods: 109 consecutive non-small cell lung cancer (n = 54) and malignant melanoma (n = 55) patients underwent whole-body FDG-PET/CT and whole-body MRI for initial tumor staging. All images were evaluated by four experienced physicians (three radiologists, one nuclear medicine physician). The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for detection of bone metastases were determined for both modalities. Statistically significant differences between FDG-PET/CT and MRI were calculated with Fisher's Exact test (p < 0.05). Clinical and imaging follow-up data with a mean follow-up time of 434 days served as the reference standard. Results: According to the reference standard 11 patients (10%) suffered from bone metastases. The sensitivity, specificity, PPV, NPV, and accuracy for the detection of osseous metastases was 45%, 99%, 83%, 94%, and 94% with whole-body FDG-PET/CT and 64%, 94%, 54%, 96%, and 91% with whole-body MRI. The difference was not statistically significant (p = 0.6147). Conclusions: FDG-PET/CT and MRI seem to be equally suitable for the detection of skeletal metastases in patients suffering from newly diagnosed non-small cell lung cancer and malignant melanoma. Both modalities go along with a substantial rate of false-negative findings requiring a close follow-up of patients who are staged free of bone metastases at initial staging.

  12. Tryptophan PET predicts spatial and temporal patterns of post-treatment glioblastoma progression detected by contrast-enhanced MRI.

    Science.gov (United States)

    Bosnyák, Edit; Kamson, David O; Robinette, Natasha L; Barger, Geoffrey R; Mittal, Sandeep; Juhász, Csaba

    2016-01-01

    Amino acid PET is increasingly utilized for the detection of recurrent gliomas. Increased amino acid uptake is often observed outside the contrast-enhancing brain tumor mass. In this study, we evaluated if non-enhancing PET+ regions could predict spatial and temporal patterns of subsequent MRI progression in previously treated glioblastomas. Twelve patients with a contrast-enhancing area suspicious for glioblastoma recurrence on MRI underwent PET scanning with the amino acid radiotracer alpha-[(11)C]-methyl-L-tryptophan (AMT). Brain regions showing increased AMT uptake in and outside the contrast-enhancing volume were objectively delineated to include high uptake consistent with glioma (as defined by previous studies). Volume and tracer uptake of such non-enhancing PET+ regions were compared to spatial patterns and timing of subsequent progression of the contrast-enhancing lesion, as defined by serial surveillance MRI. Non-enhancing PET+ volumes varied widely across patients and extended up to 24 mm from the edge of MRI contrast enhancement. In ten patients with clear progression of the contrast-enhancing lesion, the non-enhancing PET+ volumes predicted the location of new enhancement, which extended beyond the PET+ brain tissue in six. In two patients, with no PET+ area beyond the initial contrast enhancement, MRI remained stable. There was a negative correlation between AMT uptake in non-enhancing brain and time to subsequent progression (r = -0.77, p = 0.003). Amino acid PET imaging could complement MRI not only for detecting glioma recurrence but also predicting the location and timing of subsequent tumor progression. This could support decisions for surgical intervention or other targeted therapies for recurrent gliomas. PMID:26514361

  13. Remote atmospheric breakdown for standoff detection by using an intense short laser pulse.

    Science.gov (United States)

    Ting, Antonio; Alexeev, Ilya; Gordon, Daniel; Briscoe, Eldridge; Peñano, Joseph; Hubbard, Richard; Sprangle, Phillip; Rubel, Glenn

    2005-09-01

    A remote atmospheric breakdown is a very rich source of UV and broadband visible light that could provide an early warning of the presence of chemical-biological warfare agents at extended standoff distances. A negatively chirped laser pulse propagating in air compresses in time and focuses transversely, which results in a rapid laser intensity increase and ionization near the focal region that can be located kilometers away from the laser system. Proof-of-principle laboratory experiments are performed on the generation of remote atmospheric breakdown and the spectroscopic detection of mock biological warfare agents. We have generated third harmonics at 267 nm and UV broadband radiation in air from the compression and focusing of femtosecond laser pulses. Fluorescence emission from albumin aerosols as they were illuminated by the femtosecond laser pulse has been observed. PMID:16149355

  14. Detection of environmental change using hyperspectral remote sensing at Olkiluoto repository site

    International Nuclear Information System (INIS)

    In this report methods related to hyperspectral monitoring of Olkiluoto repository site are described. A short introduction to environmental remote sensing is presented, followed by more detailed description of hyperspectral imaging and a review of applications of hyperspectral remote sensing presented in the literature. The trends of future hyperspectral imaging are discussed exploring the possibilities of long-wave infrared hyperspectral imaging. A detailed description of HYPE08 hyperspectral flight campaign at the Olkiluoto region in 2008 is presented. In addition, related pre-processing and atmospheric correction methods, necessary in monitoring use, and the quality control methods applied, are described. Various change detection methods presented in the literature are described, too. Finally, a system for hyperspectral monitoring is proposed. The system is based on continued hyperspectral airborne flight campaigns and precisely defined data processing procedure. (orig.)

  15. Classification of LULC Change Detection using Remotely Sensed Data for Coimbatore City, Tamilnadu, India

    CERN Document Server

    Babykalpana, Y

    2010-01-01

    Maps are used to describe far-off places . It is an aid for navigation and military strategies. Mapping of the lands are important and the mapping work is based on (i). Natural resource management & development (ii). Information technology ,(iii). Environmental development ,(iv). Facility management and (v). e-governance. The Landuse / Landcover system espoused by almost all Organisations and scientists, engineers and remote sensing community who are involved in mapping of earth surface features, is a system which is derived from the united States Geological Survey (USGS) LULC classification system. The application of RS and GIS involves influential of homogeneous zones, drift analysis of land use integration of new area changes or change detection etc.,National Remote Sensing Agency(NRSA) Govt. of India has devised a generalized LULC classification system respect to the Indian conditions based on the various categories of Earth surface features , resolution of available satellite data, capabilities of se...

  16. Detection of TNT using a sensitive two-photon organic dendrimer for remote sensing

    International Nuclear Information System (INIS)

    There is currently a need for superior stand-off detection schemes for protection against explosive weapons of mass destruction. Fluorescence detection at small distances from the target has proven to be attractive. A novel unexplored route in fluorescence chemical sensing that utilizes the exceptional spectroscopic capabilities of nonlinear optical methods is two-photon excited fluorescence. This approach utilizes infra-red light for excitation of remote sensors. Infra-red light suffers less scattering in porous materials which is beneficial for vapor sensing and has greater depth of penetration through the atmosphere, and there are fewer concerns regarding eye safety in remote detection schemes. We demonstrate this method using a novel dendritic system which possesses both excellent fluorescence sensitivity to the presence of TNT with infra-red pulses of light and high two-photon absorption (TPA) response. This illustrates the use of TPA for potential stand-off detection of energetic materials in the infra-red spectral regions in a highly two-photon responsive dendrimer

  17. Detection of TNT using a sensitive two-photon organic dendrimer for remote sensing

    Energy Technology Data Exchange (ETDEWEB)

    Narayanan, Aditya; Varnavski, Oleg; Goodson, Theodore III [Department of Chemistry and Macromolecular Science and Engineering, NSF Center for Ultra-fast Optical Science (FOCUS), University of Michigan, Ann Arbor, MI 48109 (United States); Mongin, Oliver; Blanchard-Desce, Mireille [Synthese et ElectroSynthese Organiques (CNRS, UMR 6510), Universite de Rennes 1, Institut de Chimie, Campus Scientifique de Beaulieu, Bat 10A, F-35042 Rennes Cedex (France); Majoral, Jean-Pierre [Laboratoire de Chimie de Coordination, CNRS, 205 route de Narbonne, F-31077, Toulouse Cedex 4 (France)], E-mail: tgoodson@umich.edu

    2008-03-19

    There is currently a need for superior stand-off detection schemes for protection against explosive weapons of mass destruction. Fluorescence detection at small distances from the target has proven to be attractive. A novel unexplored route in fluorescence chemical sensing that utilizes the exceptional spectroscopic capabilities of nonlinear optical methods is two-photon excited fluorescence. This approach utilizes infra-red light for excitation of remote sensors. Infra-red light suffers less scattering in porous materials which is beneficial for vapor sensing and has greater depth of penetration through the atmosphere, and there are fewer concerns regarding eye safety in remote detection schemes. We demonstrate this method using a novel dendritic system which possesses both excellent fluorescence sensitivity to the presence of TNT with infra-red pulses of light and high two-photon absorption (TPA) response. This illustrates the use of TPA for potential stand-off detection of energetic materials in the infra-red spectral regions in a highly two-photon responsive dendrimer.

  18. Remote concealed threat detection by novel classification algorithms applied to multi-polarimetric UWB radar

    Science.gov (United States)

    O'Reilly, Dean; Bowring, Nicholas; Rezgui, Nacer Ddine; Andrews, David; Harmer, Stuart

    2013-05-01

    A method of effectively detecting remote concealed threats, particularly knives and guns, has been developed. This method uses multi-polarimetric ultra wide band active microwave radar to remotely scan a person under investigation. It has been shown that the radar signatures from such scans can be used to detect whether a person is carrying a concealed threat. A Principal Component Analysis (PCA) data reduction technique followed by a neural network (NN) is used to classify the information extracted from the radar signals. The technique combines the co, 45°, cross, and 135° polarized transceived radar signals into a single data set for classification. Illuminating the target with a range of polarizations, together with choosing a radar beam size commensurate with the targets in question, produces good discrimination between threat and non-threat items. Once collected, the data sets obtained are reduced via PCA, which significantly improves the correct classification rate at the NN stage and makes the technique more tolerant of variations in the threat objects orientation and better able to detect a wider range of threat types. Experimental results are presented which show that a detection rate of up to 80% for knives and guns can be achieved, with a false alarm rate as low as 4%.

  19. Remote detection of oil spilled under ice and snow using nuclear magnetic resonance

    International Nuclear Information System (INIS)

    The technical challenge of detecting oil that has been accidentally spilled under ice and snow was discussed with particular reference to the tools used to characterize the molecular composition of liquids and solids. One such tool is nuclear magnetic resonance (NMR) which works by releasing electromagnetic energy. The NMR signals from oil and water can be differentiated based on the inherent differences in the NMR signal responses from different fluid types. The method can also use the Earth's magnetic field as the static magnetic field and thereby eliminate the complexity and cost of generating an independent magnetic field for remotely detecting fluids below a surface. This study examined the feasibility of altering existing surface-based instruments and placing them in a helicopter for aerial monitoring. The goal of this research was to develop a tool for remote detection of oil under ice in a marine environment, or for detection of oil under snow on land using an inexpensive tool that can quickly inspect large areas. The proposed tool and technique produces a direct hydrocarbon signal that may not have interference from ice and snow. 9 refs., 6 figs

  20. Dynamic MRI-based computer aided diagnostic systems for early detection of kidney transplant rejection: A survey

    Science.gov (United States)

    Mostapha, Mahmoud; Khalifa, Fahmi; Alansary, Amir; Soliman, Ahmed; Gimel'farb, Georgy; El-Baz, Ayman

    2013-10-01

    Early detection of renal transplant rejection is important to implement appropriate medical and immune therapy in patients with transplanted kidneys. In literature, a large number of computer-aided diagnostic (CAD) systems using different image modalities, such as ultrasound (US), magnetic resonance imaging (MRI), computed tomography (CT), and radionuclide imaging, have been proposed for early detection of kidney diseases. A typical CAD system for kidney diagnosis consists of a set of processing steps including: motion correction, segmentation of the kidney and/or its internal structures (e.g., cortex, medulla), construction of agent kinetic curves, functional parameter estimation, diagnosis, and assessment of the kidney status. In this paper, we survey the current state-of-the-art CAD systems that have been developed for kidney disease diagnosis using dynamic MRI. In addition, the paper addresses several challenges that researchers face in developing efficient, fast and reliable CAD systems for the early detection of kidney diseases.

  1. Early detection of femoral head avascular necrosis by bone SPECT compared to MRI in renal allograft recipients

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Do Young; Yang, Seoung Oh; Lee, Hee Kyung; Han, Duck Jong; Shin, Myung Jin [Asan Mecical Center, Seoul (Korea, Republic of)

    1997-07-01

    The prevalence of avascular necrosis (AVN) of femoral head in patients who receive immunosuppresive agents after renal transplantation is reported to be 4-29%. Among patients who develop AVN after renal transplantation, 80% become symptomatic within 2 years after transplantation. As the number of renal transplantation has been increased recently, early detection of femoral head AVN is very important because early surgical core decompression of femoral head can prevent collapse of the head. MRI is known to be very sensitive to diagnose femoral head AVN. However in three cases we report here, bone SPECT showed early changes of femoral head AVN, whereas MRI showed no specific abnormality. Case 1. A 53-year-old female received an allograft kidney transplantation in 1994. Preoperative bone scan was normal. She complained of both hip pain on Mar. 18 1997. Bone SPECT showed cold defect in both femoral heads but MRI showed no abnormality. After 3 months, bone SPECT and MRI showed AVN of both femoral heads. She underwent bilateral total hip replacement arthroplasty. AVN of femoral heads was confirmed by microscopic examination. Case 2. A 38-year-old female received an allograft kidney transplantation in Feb. 27 1997. Preoperative bone scan was normal. She ran a fever and creatinine was elevated from 1.2 to 2.8 mg/dL. She took high dose methylprednisolone therapy for acute reanl rejection. After two days, she complained pain in both hip joints and knee joints. Bone SPECT showed cold defects in both femoral heads but MRI showed no abnormality. A follow-up bone SPECT and MRI 20 days later revealed AVN of both femoral heads. Case 3. A 50-year-old male received an allograft kidney transplantation on Jul. 12 1995. Preoperative bone scan was normal. He complained of right hip pain on Jul, 26 1995. His bone SPECT showed cold defects in both femoral heads while MRI showed only minimal hip joint effusion. He also complained of left hip pain on Oct. 2 1995. He was admitted on Mar 17 1996 because of both hip pain and fever. MRI showed advanced AVN of femoral heads was confirmed by microscopic examination. Bone SPECT can diagnose early AVN of femoral head in renal allograft recipients when MRI could be normal.

  2. Early detection of femoral head avascular necrosis by bone SPECT compared to MRI in renal allograft recipients

    International Nuclear Information System (INIS)

    The prevalence of avascular necrosis (AVN) of femoral head in patients who receive immunosuppresive agents after renal transplantation is reported to be 4-29%. Among patients who develop AVN after renal transplantation, 80% become symptomatic within 2 years after transplantation. As the number of renal transplantation has been increased recently, early detection of femoral head AVN is very important because early surgical core decompression of femoral head can prevent collapse of the head. MRI is known to be very sensitive to diagnose femoral head AVN. However in three cases we report here, bone SPECT showed early changes of femoral head AVN, whereas MRI showed no specific abnormality. Case 1. A 53-year-old female received an allograft kidney transplantation in 1994. Preoperative bone scan was normal. She complained of both hip pain on Mar. 18 1997. Bone SPECT showed cold defect in both femoral heads but MRI showed no abnormality. After 3 months, bone SPECT and MRI showed AVN of both femoral heads. She underwent bilateral total hip replacement arthroplasty. AVN of femoral heads was confirmed by microscopic examination. Case 2. A 38-year-old female received an allograft kidney transplantation in Feb. 27 1997. Preoperative bone scan was normal. She ran a fever and creatinine was elevated from 1.2 to 2.8 mg/dL. She took high dose methylprednisolone therapy for acute reanl rejection. After two days, she complained pain in both hip joints and knee joints. Bone SPECT showed cold defects in both femoral heads but MRI showed no abnormality. A follow-up bone SPECT and MRI 20 days later revealed AVN of both femoral heads. Case 3. A 50-year-old male received an allograft kidney transplantation on Jul. 12 1995. Preoperative bone scan was normal. He complained of right hip pain on Jul, 26 1995. His bone SPECT showed cold defects in both femoral heads while MRI showed only minimal hip joint effusion. He also complained of left hip pain on Oct. 2 1995. He was admitted on Mar 17 1996 because of both hip pain and fever. MRI showed advanced AVN of femoral heads was confirmed by microscopic examination. Bone SPECT can diagnose early AVN of femoral head in renal allograft recipients when MRI could be normal

  3. Gadoxetic acid-enhanced MRI and diffusion-weighted imaging for the detection of colorectal liver metastases after neoadjuvant chemotherapy

    International Nuclear Information System (INIS)

    To investigate the diagnostic performance of gadoxetic acid-enhanced MRI including diffusion-weighted imaging (DWI) for the detection of colorectal liver metastases (CRLMs) after neoadjuvant chemotherapy (NAC). Our study population comprised 77 patients with 140 CRLMs who underwent gadoxetic acid-enhanced MRI within 1 month prior to surgery: group A (without NAC, n = 38) and group B (with NAC, n = 39). Two radiologists independently assessed all MR images and graded their diagnostic confidence for CRLM on a 5-point scale. Diagnostic accuracy, sensitivity and positive predictive values (PPV) were calculated and compared between the two groups. Diagnostic accuracy of gadoxetic acid-enhanced MRI in group B was slightly lower than in group A, but a statistically significant difference was not observed (observer 1: Az, 0.926 in group A, 0.905 in group B; observer 2: Az, 0.944 in group A, 0.885 in group B; p > 0.05). Sensitivity and PPV of group B were comparable to those of group A (observer 1: sensitivity = 93.5 % vs. 93.6 %, PPV = 95.1 % vs. 86.9 %; observer 2: sensitivity = 96.8 % vs. 91.0 %; PPV = 90.0 % vs. 89.7 %; all p > 0.05). Gadoxetic acid-enhanced MRI including DWI provided good diagnostic performance with high sensitivity (>90 %) for the detection of CRLMs, regardless of the influence of NAC. (orig.)

  4. Gadoxetic acid-enhanced MRI and diffusion-weighted imaging for the detection of colorectal liver metastases after neoadjuvant chemotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Mi Hye [Konkuk University Medical Center, Department of Radiology, Seoul (Korea, Republic of); Lee, Jeong Min; Han, Joon Koo; Choi, Byung-Ihn [Seoul National University Hospital, Department of Radiology, Seoul (Korea, Republic of); Hur, Bo Yun [Boramae Medical Center, Department of Radiology, Seoul (Korea, Republic of); Kim, Tae-You [Seoul National University Hospital, Department of Internal Medicine, Seoul (Korea, Republic of); Jeong, Seung-Yong; Yi, Nam-Joon; Suh, Kyung-Suk [Seoul National University Hospital, Department of Surgery, Seoul (Korea, Republic of)

    2015-08-15

    To investigate the diagnostic performance of gadoxetic acid-enhanced MRI including diffusion-weighted imaging (DWI) for the detection of colorectal liver metastases (CRLMs) after neoadjuvant chemotherapy (NAC). Our study population comprised 77 patients with 140 CRLMs who underwent gadoxetic acid-enhanced MRI within 1 month prior to surgery: group A (without NAC, n = 38) and group B (with NAC, n = 39). Two radiologists independently assessed all MR images and graded their diagnostic confidence for CRLM on a 5-point scale. Diagnostic accuracy, sensitivity and positive predictive values (PPV) were calculated and compared between the two groups. Diagnostic accuracy of gadoxetic acid-enhanced MRI in group B was slightly lower than in group A, but a statistically significant difference was not observed (observer 1: A{sub z}, 0.926 in group A, 0.905 in group B; observer 2: A{sub z}, 0.944 in group A, 0.885 in group B; p > 0.05). Sensitivity and PPV of group B were comparable to those of group A (observer 1: sensitivity = 93.5 % vs. 93.6 %, PPV = 95.1 % vs. 86.9 %; observer 2: sensitivity = 96.8 % vs. 91.0 %; PPV = 90.0 % vs. 89.7 %; all p > 0.05). Gadoxetic acid-enhanced MRI including DWI provided good diagnostic performance with high sensitivity (>90 %) for the detection of CRLMs, regardless of the influence of NAC. (orig.)

  5. Detection of volume loss in hippocampal layers in Alzheimer's disease using 7 T MRI: A feasibility study

    Directory of Open Access Journals (Sweden)

    Claire Boutet

    2014-01-01

    Full Text Available In Alzheimer's disease (AD, the hippocampus is an early site of tau pathology and neurodegeneration. Histological studies have shown that lesions are not uniformly distributed within the hippocampus. Moreover, alterations of different hippocampal layers may reflect distinct pathological processes. 7 T MRI dramatically improves the visualization of hippocampal subregions and layers. In this study, we aimed to assess whether 7 T MRI can detect volumetric changes in hippocampal layers in vivo in patients with AD. We studied four AD patients and seven control subjects. MR images were acquired using a whole-body 7 T scanner with an eight channel transmit–receive coil. Hippocampal subregions were manually segmented from coronal T2*-weighted gradient echo images with 0.3 × 0.3 × 1.2 mm3 resolution using a protocol that distinguishes between layers richer or poorer in neuronal bodies. Five subregions were segmented in the region of the hippocampal body: alveus, strata radiatum, lacunosum and moleculare (SRLM of the cornu Ammonis (CA, hilum, stratum pyramidale of CA and stratum pyramidale of the subiculum. We found strong bilateral reductions in the SRLM of the cornu Ammonis and in the stratum pyramidale of the subiculum (p < 0.05, with average cross-sectional area reductions ranging from ?29% to ?49%. These results show that it is possible to detect volume loss in distinct hippocampal layers using segmentation of 7 T MRI. 7 T MRI-based segmentation is a promising tool for AD research.

  6. Incremental value of diffusion weighted and dynamic contrast enhanced MRI in the detection of locally recurrent prostate cancer after radiation treatment: preliminary results

    International Nuclear Information System (INIS)

    To assess the incremental value of diffusion-weighted (DW-MRI) and dynamic contrast-enhanced MRI (DCE-MRI) to T2-weighted MRI (T2WI) in detecting locally recurrent prostate cancer after radiotherapy. Twenty-four patients (median age, 70 years) with a history of radiotherapy-treated prostate cancer underwent multi-parametric MRI (MP-MRI) and transrectal prostate biopsy. Two readers independently scored the likelihood of cancer on a 1-5 scale, using T2WI alone and then adding DW-MRI and DCE-MRI. Areas under receiver operating characteristic curves (AUCs) were estimated at the patient and prostate-side levels. The apparent diffusion coefficient (ADC) from DW-MRI and the Ktrans, kep, ve, AUGC90 and AUGC180 from DCE-MRI were recorded. Biopsy was positive in 16/24 (67%) and negative in 8/24 (33%) patients. AUCs for readers 1 and 2 increased from 0.64 and 0.53 to 0.95 and 0.86 with MP-MRI, at the patient level, and from 0.73 and 0.66 to 0.90 and 0.79 with MP-MRI, at the prostate-side level (p values -3 mm2/s)], median Ktrans [1.07 vs. 0.34 (1/min)], and kep [2.06 vs 1.0 (1/min)] (p values < 0.05). MP-MRI was significantly more accurate than T2WI alone in detecting locally recurrent prostate cancer after radiotherapy. (orig.)

  7. Incremental value of diffusion weighted and dynamic contrast enhanced MRI in the detection of locally recurrent prostate cancer after radiation treatment: preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Akin, Oguz; Vargas, Hebert Alberto; Hricak, Hedvig [Memorial Sloan-Kettering Cancer Center, Department of Radiology, New York, NY (United States); Gultekin, David H. [Memorial Sloan-Kettering Cancer Center, Medical Physics, New York, NY (United States); Zheng, Junting; Moskowitz, Chaya [Memorial Sloan-Kettering Cancer Center, Epidemiology and Biostatistics, New York, NY (United States); Pei, Xin; Sperling, Dahlia; Zelefsky, Michael J. [Memorial Sloan-Kettering Cancer Center, Radiation Oncology, New York, NY (United States); Schwartz, Lawrence H. [Columbia University College of Physicians and Surgeons, Radiology, New York, NY (United States)

    2011-09-15

    To assess the incremental value of diffusion-weighted (DW-MRI) and dynamic contrast-enhanced MRI (DCE-MRI) to T2-weighted MRI (T2WI) in detecting locally recurrent prostate cancer after radiotherapy. Twenty-four patients (median age, 70 years) with a history of radiotherapy-treated prostate cancer underwent multi-parametric MRI (MP-MRI) and transrectal prostate biopsy. Two readers independently scored the likelihood of cancer on a 1-5 scale, using T2WI alone and then adding DW-MRI and DCE-MRI. Areas under receiver operating characteristic curves (AUCs) were estimated at the patient and prostate-side levels. The apparent diffusion coefficient (ADC) from DW-MRI and the K{sup trans}, k{sub ep}, v{sub e}, AUGC90 and AUGC180 from DCE-MRI were recorded. Biopsy was positive in 16/24 (67%) and negative in 8/24 (33%) patients. AUCs for readers 1 and 2 increased from 0.64 and 0.53 to 0.95 and 0.86 with MP-MRI, at the patient level, and from 0.73 and 0.66 to 0.90 and 0.79 with MP-MRI, at the prostate-side level (p values < 0.05). Biopsy-positive and biopsy-negative prostate sides differed significantly in median ADC [1.44 vs. 1.68 (x 10{sup -3} mm{sup 2}/s)], median K{sup trans} [1.07 vs. 0.34 (1/min)], and k{sub ep} [2.06 vs 1.0 (1/min)] (p values < 0.05). MP-MRI was significantly more accurate than T2WI alone in detecting locally recurrent prostate cancer after radiotherapy. (orig.)

  8. Detecting Alzheimer’s disease by morphological MRI using hippocampal grading and cortical thickness

    DEFF Research Database (Denmark)

    Eskildsen, Simon Fristed; Coupé, Pierrick; Fonov, Vladimir; Collins, D. Louis

    Structural MRI is an important imaging biomarker in Alzheimer’s disease as the cerebral atrophy has been shown to closely correlate with cogni-tive symptoms. Recognizing this, numerous methods have been developed for quantifying the disease related atrophy from MRI over the past decades. Special...

  9. Remote detection of methane with a 1.66-microm diode laser.

    Science.gov (United States)

    Uehara, K; Tai, H

    1992-02-20

    High-sensitivity real-time remote detection of methane in air with a 1.66-microm distributed-feedback diode laser operating at room temperature is demonstrated by laboratory simulations. The laser current was modulated at a high frequency of ~5 MHz, and the laser-center frequency was locked onto a methane-absorption line. The laser light directed toward the probed region was received after one-way transmission or further reflection from a topographic target. The methane absorption was detected by the second-harmonic component in the optical-power variation. The minimum-detectable concentration-path-length product in the transmission scheme was 0.3 part in 10(6) m for a signal averaging time of 1.3 s. In the reflection scheme, the amount of methane could be measured from the ratio of the fundamental and second-harmonic signal intensities independently of the received power. PMID:20720687

  10. MRI detection of brain metastases at initial staging of small-cell lung cancer

    International Nuclear Information System (INIS)

    We prospectively investigated 40 patients with small-cell carcinoma of the lung (SCLC) for signs of brain metastasis by neurological examination and MRI of the brain, to determine the significance of MRI for staging. MRI could not be completed in one patient, who was excluded from the study. The MRI studies of the remaining patients showed no abnormalities in 12, cerebral infarcts in 2 and brain metastases in 11 patients, of whom 3 no relevant symptoms. Nonenhancing white matter lesions were found in 14 patients. In 3 of the 4 patients with an abnormal neurological examination at diagnosis, nonenhancing white matter lesions later developed into contrast enhancing lesions compatible with breain metastases; in 2, this occurred during the course of the chemotherapy. MRI did not change the clinical staging in patients with asymptomatic brain metastases. (orig.)

  11. Structural health monitoring of wind towers: remote damage detection using strain sensors

    International Nuclear Information System (INIS)

    Exploiting wind energy in complex sites like mountain terrains implies the necessity for remote structural health monitoring of the wind towers. In fact, such slender vertical structures exposed to wind may experience large vibrations and repeated stress cycles leading to fatigue cracking. Possible strategies for remote fatigue damage detection are investigated. Specifically, this paper is focused on the use of suitable strain sensors for crack detection in critical sites of the structure, suggesting several strategies taking into account the possibility of wind direction changes and/or wind calm phases. They are based on a radial arrangement of strain sensors around the tower periphery in the vicinity of the base weld joint. The most promising strategy uses the strain difference between adjacent strain sensors as an index of the presence of a crack. The number of sensors to be installed is dictated by the minimum crack size to be detected, which in turn depends on the expected extreme wind conditions and programmed inspection/repair schedule for the structure

  12. Oil spill detection and remote sensing : an overview with focus on recent events

    International Nuclear Information System (INIS)

    Several offshore oil spills occurred during the period from November to December 2007 in various parts of the world, each highlighting the need of quickly detect oil spills in marine settings. Several factors must be considered in order to determine the best technical approach for successful detection and oil spill monitoring. These include the reason for detection or monitoring; the location of the spill; the scale of spatial coverage; availability of detection equipment and time to deploy; high specificity for petroleum oil; weather conditions at and above the spill site; and cost of the detection approach. This paper outlined some of the key attributes of several remote sensing options that are available today or being considered. The approaches used to enhance visualization or detection of spills include traditional electromagnetic spectrum-based approaches such as ultra violet (UV), visible, infra-red (IR), radar, and fluorescence-based systems. Analytical approaches such as chemical analysis for the detection of volatile organic compounds (VOCs) or monitoring of electrical conductivity of the water surface may also provide a warning that hydrocarbons have been released. 12 refs., 3 tabs., 11 figs

  13. Investigation of performance, noise and detectability characteristics of small-scale remotely piloted vehicle /RPV/ propellers

    Science.gov (United States)

    Janakiram, D. S.; Scruggs, B. W.

    1981-10-01

    Several small-scale propeller configurations, applicable to a conceptual remotely piloted vehicle, were tested under static and simulated forward flight conditions in a wind tunnel to determine their performance, acoustic, and detectability characteristics. The propellers tested had tractor, pusher, and ducted configurations, designed to develop 4 thrust horsepower at a cruise speed of 75 knots at 4000 ft altitude and 95 F. The acoustic data were used to determine the slant range and altitude of no detection of each propeller configuration. The acoustic and detectability characteristics of small-scale propellers were found to be significantly different from those of the large-scale propellers; this is explained by low disk loading or the low operating Reynolds numbers of the propellers. An increase in forward velocity caused a significant drop in SPLs at higher harmonics of the blade passage frequency. Tip speed had a strong effect on noise and detectability in forward flight: most of the propellers were detected at either the first or second harmonic of their blade passage frequency. Three-bladed propellers were generally less detectable than twoor four-bladed propellers for most of the forward velocities. Finally, ducted and pusher propeller configurations were more detectable and less efficient than their free and tractor counterparts.

  14. Cardiac MRI. Diagnostic gain of an additional axial SSFP chest sequence for the detection of potentially significant extracardiac findings in the cardiac MRI examination setting

    Energy Technology Data Exchange (ETDEWEB)

    Roller, F.C.; Schneider, C.; Krombach, G.A. [University Hospital Giessen (Germany). Dept. Radiology; Schuhbaeck, A. [University Hospital Giessen (Germany). Dept. Cardiology; Rolf, A. [Kerckhoff Hospital Bad Nauheim (Germany). Dept. Cardiology

    2014-01-15

    Purpose: Cardiac MRI (CMRI) is an effective method for imaging of the heart. The aim of our study was to assess whether an axial chest sequence in addition to the standard CMR examination setting has advantages in the detection of potentially significant extracardiac findings (PSEF). Materials and Methods: 400 consecutive patients were imaged at 1.5 T for clinical reasons. In addition to the standard long and short-axis views, an axial SSFP sequence was obtained covering the thorax from the lung apex to the diaphragm. All sequences were separately evaluated for PSEF. Results: A total of 25 PSEF were diagnosed in 400 patients, including 16 pleural effusions, a pulmonary fibrosis, a spondylodiscitis, ascites, lymphadenopathies, relapse of a mamma carcinoma, growth of adrenal glands metastases and diaphragmatic elevation. All 25 PSEF were detected by reading survey sequences. 24 of the 25 PSEF were detected by the additional SSFP chest sequence as well as the CINE sequences. Conclusion: In our study the additional axial SSFP chest sequence didn't show a benefit in the detection of PSEF. With the survey sequences we were able to detect all PSEF. We conclude that survey images should be assessed for additional findings. (orig.)

  15. Detection of liver lesions: Comparative evaluation of superparamagnetic iron oxides-enhanced MRI (AMI-25, ENDOREM trademark) with US, CT, and CT portography

    International Nuclear Information System (INIS)

    The study reported was intended to reveal the clinical value of ENDOREM trademark as a contrast agent for MRI. The results have been compared with those obtained with ultrasonic scanning, CT, conventional MRI without contrast enhancement, and CT portography. The criterium for comparison was the number of lesions detected. (orig./CB)

  16. Detection of local recurrent prostate cancer after radical prostatectomy in terms of salvage radiotherapy using dynamic contrast enhanced-MRI without endorectal coil

    Directory of Open Access Journals (Sweden)

    Rischke Hans Christian

    2012-10-01

    Full Text Available Abstract Purpose To evaluate the value of dynamic contrast enhanced Magnetic Resonance Imaging (DCE-MRI without endorectal coil (EC in the detection of local recurrent prostate cancer (PC after radical prostatectomy (RP. Material and methods Thirty-three patients with recurrent PC underwent DCE-MRI without EC before salvage radiotherapy (RT. At median 15 (mean 16±4.9, range 12–27 months after completion of RT all patients showed complete biochemical response. Additional follow up post RT DCE-MRI scans were available. Prostate specific antigen (PSA levels at the time of imaging were correlated to the imaging findings. Results In 22/33 patients (67% early contrast enhancing nodules were detected in the post-prostatectomy fossa on pre-RT DCE-MRI images. The average pre-RT PSA level of the 22 patients with positive pre-RT DCE-MRI findings was significantly higher (mean, 0.74±0.64 ng/mL compared to the pre-RT PSA level of the 11 patients with negative pre-RT DCE-MRI (mean, 0.24±0.13 ng/mL (p Conclusions This is the first study that shows that DCE-MRI without EC can detect local recurrent PC with an estimated accuracy of 83% at low PSA levels. All false negative DCE-MRI scans were detected using a PSA cut-off of ?0.54 ng/mL.

  17. Contextualizing Neuro-Collaborations: Reflections on a Transdisciplinary fMRI Lie Detection Experiment

    Directory of Open Access Journals (Sweden)

    Melissa M. Littlefield

    2014-03-01

    Full Text Available Recent neuroscience initiatives (including the E.U.’s Human Brain Project and the U.S.’s BRAIN Initiative have reinvigorated discussions about the possibilities for transdisciplinary collaboration between the neurosciences, the social sciences, and the humanities. As STS scholars have argued for decades, however, such inter- and transdisciplinary collaborations are potentially fraught with tensions between researchers. This essay build on such claims by arguing that the tensions of transdisciplinary research also exist within researchers’ own experiences of working between disciplines – a phenomenon that we call ‘Disciplinary Double Consciousness’ (DDC. Building on previous work that has characterized similar spaces (and especially on the Critical Neuroscience literature, we argue that ‘neuro-collaborations’ inevitably engage researchers in DDC – a phenomenon that allows us to explore the useful dissonance that researchers can experience when working between a “home” discipline and a secondary discipline. Our case study is a five-year case study in fMRI lie detection involving a transdisciplinary research team made up of social scientists, a neuroscientist, and a humanist. In addition to theorizing neuro-collaborations from the inside-out, this essay presents practical suggestions for developing transdisciplinary infrastructures that could support future neuro-collaborations.

  18. Comparative study of diffusion weighted imaging and dynamic contrast enhanced MRI for the detection of small breast cancers

    International Nuclear Information System (INIS)

    Objective: To compare the sensitivity of diffusion weighted imaging (DWI) with dynamic contrast enhanced (DCE) MRI for the detection of small breast cancers and to evaluate the clinical value of DWI. Methods: Forty-eight patients with benign (n=25) and malignant (n=45) small breast lesions (?2 cm) proved by pathology underwent DWI and DCE MRI. The DCE MRI was performed using FLASH sequence and the time-signal intensity curve was drawn. The DWI was performed using GRAPPA- EPI sequence with different b values (800, 1000 s/mm2) and the ADC values of lesions were measured. The sensitivity and specificity of DWI for the detection of small breast cancers were compared with DCE MRI. Results: Forty of 45 small breast cancers and 19 of 25 small benign breast lesions were correctly diagnosed using DCE MRI. The sensitivity and positive predictive value of TIC were 88.9% (40/45) and 87.0% (40/46). With b values of 800 s/mm2 and 1000 s/mm2, the average ADC values of small breast cancers were (1.153±0.192) x 10-3 and (1.079±0.186) x 10-3 mm2/s, while those of benign ones were (1.473±0.252) x 10-3 and (1.419 ± 0.255) x 10-3 mm2/s, respectively. There was no significant difference for the ADC values with different b values in the same group (P>0.05), while there was a significant difference between the malignant and the benign lesions (P2. Both the sensitivity and positive predictive value of diagnosis were 86.7% (39/45). The abilities of DWI and DCE MRI for the diagnosis of small breast cancers were the same. The sensitivity (93.3%) and positive predictive value (91.3%) were improved with the combination of DCE MRI and DWI. Conclusion: DWI has a high sensitivity for the detection of small breast cancers, the ADC value can provide valuable information in the differential diagnosis. (authors)

  19. Use of an Eye-Safe, Portable LIDAR for Remote Wildland Fire and Smoke Detection

    Energy Technology Data Exchange (ETDEWEB)

    MATTHEW, PARKER

    2004-11-29

    During periods of drought when surface water supplies are severely limited, wildland forest fires tend to become more frequent and often can grow into major fires that threaten valuable timber, real estate, and even human lives. Fire-fighting crews are critically dependent upon accurate and timely weather data to help ensure that individuals are not inadvertently exposed to dangerous conditions and to enhance normal fire-fighting activities. To that end, the use of an eye-safe, portable lidar for remote wildland fire and smoke detection is described.

  20. Technology Gap Analysis for the Detection of Process Signatures Using Less Than Remote Methods

    Energy Technology Data Exchange (ETDEWEB)

    Hartman, John S.; Atkinson, David A.; Lind, Michael A.; Maughan, A. D.; Kelly, James F.

    2005-01-01

    Although remote sensing methods offer advantages for monitoring important illicit process activities, remote and stand-off technologies cannot successfully detect all important processes with the sensitivity and certainty that is desired. The main scope of the program is observables, with a primary focus on chemical signatures. A number of key process signatures elude remote or stand-off detection for a variety of reasons (e.g., heavy particulate emissions that do not propagate far enough for detection at stand-off distances, semi-volatile chemicals that do not tend to vaporize and remain in the environment near the source, etc.). Some of these compounds can provide persistent, process-specific information that is not available through remote techniques; however, the associated measurement technologies have their own set of advantages, disadvantages and technical challenges that may need to be overcome before additional signature data can be effectively and reliably exploited. The main objective of this report is to describe a process to identify high impact technology gaps for important less-than-remote detection applications. The subsequent analysis focuses on the technology development needed to enable exploitation of important process signatures. The evaluation process that was developed involves three interrelated and often conflicting requirements generation activities: • Identification of target signature chemicals with unique intelligence value and their associated attributes as mitigated by environmentally influenced fate and transport effects (i.e., what can you expect to actually find that has intelligence value, where do you need to look for it and what sensitivity and selectivity do you need to see it) • Identification of end-user deployment scenario possibilities and constraints with a focus on alternative detection requirements, timing issues, logistical consideration, and training requirements for a successful measurement • Identification of available measurement technology alternatives and their associated attributes (available off-the-shelf, in near-term development, likely longer-term development and research-phase possibilities). Assembling these requirements into attribute verses generic acceptance criteria level tables and then comparing related attributes between tables allows for rapid visualization of technology gaps and gross estimates of the gap size. By simply weighting the attributes and the requirements in various ways one can also derive the importance of the identified technology gaps. This output can provide the basis for both a near-term technology development roadmap and research focus as well as a decision support tool for selecting the “most likely to succeed” approach. The evaluation process as presented is generally applicable for the determination of measurement technology gaps for a broad range of applications [e.g., nuclear weapons process, chemical weapons production, biological weapons production as well as classical signature categories (e.g., chemical and radionuclide signatures)]. In this paper the method is applied to the specific case of detecting nuclear weapons production processes using semi-volatile chemical signatures as an illustration. This particular case selection allows the leveraging of significant prior knowledge and experience while still being highly relevant to current detection scenario needs.

  1. Memory detection using fMRI - does the encoding context matter?

    Science.gov (United States)

    Peth, Judith; Sommer, Tobias; Hebart, Martin N; Vossel, Gerhard; Büchel, Christian; Gamer, Matthias

    2015-06-01

    Recent research revealed that the presentation of crime related details during the Concealed Information Test (CIT) reliably activates a network of bilateral inferior frontal, right medial frontal and right temporal-parietal brain regions. However, the ecological validity of these findings as well as the influence of the encoding context are still unclear. To tackle these questions, three different groups of subjects participated in the current study. Two groups of guilty subjects encoded critical details either only by planning (guilty intention group) or by really enacting (guilty action group) a complex, realistic mock crime. In addition, a group of informed innocent subjects encoded half of the relevant details in a neutral context. Univariate analyses showed robust activation differences between known relevant compared to neutral details in the previously identified ventral frontal-parietal network with no differences between experimental groups. Moreover, validity estimates for average changes in neural activity were similar between groups when focusing on the known details and did not differ substantially from the validity of electrodermal recordings. Additional multivariate analyses provided evidence for differential patterns of activity in the ventral fronto-parietal network between the guilty action and the informed innocent group and yielded higher validity coefficients for the detection of crime related knowledge when relying on whole brain data. Together, these findings demonstrate that an fMRI-based CIT enables the accurate detection of concealed crime related memories, largely independent of encoding context. On the one hand, this indicates that even persons who planned a (mock) crime could be validly identified as having specific crime related knowledge. On the other hand, innocents with such knowledge have a high risk of failing the test, at least when considering univariate changes of neural activation. PMID:25819306

  2. A technique to reduce motion artifact for externally triggered cine-MRI(EC-MRI) based on detecting the onset of the articulated word with spectral analysis

    International Nuclear Information System (INIS)

    One issue in externally triggered cine-magnetic resonance imaging (EC-MRI) for the dynamic observation of speech organs is motion artifact in the phase-encoding direction caused by unstable repetitions of speech during data acquisition. We propose a technique to reduce such artifact by rearranging the k-space data used to reconstruct MR images based on the analysis of recorded speech sounds. We recorded the subject's speech sounds during EC-MRI and used post hoc acoustical processing to reduce scanning noise and detect the onset of each utterance based on analysis of the recorded sounds. We selected each line of k-space from several data acquisition sessions and rearranged them to reconstruct a new series of dynamic MR images according to the analyzed time of utterance onset. Comparative evaluation showed significant reduction in motion artifact signal in the dynamic MR images reconstructed by the proposed method. The quality of the reconstructed images was sufficient to observe the dynamic aspects of speech production mechanisms. (author)

  3. Remote Field Eddy Current Probes for the Detection of Stress Corrosion in Transmission Pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Plamen Alexandroz Ivanov

    2002-08-27

    Magnetic flux leakage (MFL) is a technique used widely in non-destructive testing (NDT) of natural gas and petroleum transmission pipelines. This inspection method relies on magnetizing the pipe-wall in axial direction. The MFL inspection tool is equipped with an array of Hall sensors located around the circumference of the pipe, which registers the flux leakage caused by any defects present in the pipe-wall. Currently, the tool magnetizes the pipewall in axial direction making it largely insensitive to axially oriented defects. One type of defect, which is of a growing concern in the gas and petroleum industry is the stress corrosion crack (SCC). The SCCs are a result of aging, corrosion, fatigue and thermal stresses. SCCs are predominantly axially oriented and are extremely tight, which makes them impossible to be detected using current inspection technology. A possible solution to this problem is to utilize the remote field eddy current (RFEC) effect to detect axially oriented defects. The RFEC method has been widely used in industry in the inspection of tubular products. The method uses a pair of excitation and pick-up coils. The pick-up coil located in the remote field region, usually two, three pipe-diameters away from the excitation coil. With RFEC the presence of defects is detected by the disturbance in the phase of the signal measured by the pick-up coil relative to that of the excitation coil. Unlike conventional eddy current testing the RFEC method is sensitive to defects on the exterior of the inspected product, which makes it a good candidate for the development of in-line inspection technology. This work focuses on the development of non-destructive testing technique, which uses remote field eddy currents induced by rotating magnetic field (RMF). A major advantage of the RMF is that it makes possible to not only detect a defect but also localize its position in circumferential direction. Also, it could potentially allow detection of defects, regardless of their shape and orientation. In this work the RFEC-RMF technique is investigated and is shown to be a useful tool in the detection of axially oriented, circumferentially oriented and skewed notches, SCCs and round defects. Finally, a data acquisition system is designed, capable of performing the RFEC-RMF measurements automatically.

  4. Brain MRI segmentation by snakes. Image processing for the detection of functional areas affected by stroke in the brain MRI

    Directory of Open Access Journals (Sweden)

    Yazid Cherfa

    2010-06-01

    Full Text Available Segmentation by active contours is a special technique; its main advantage is that it provides an a priori guarantee that a contour will always consist of a string of points. This eliminates the need for monitoring algorithms to decide whether or not specific pixels need to be included in the contour. In other approaches contour points rarely form closed curves, and a closing step is usually is necessary. A further advantage of the active contour technique is that it allows segmentation even when contours are not sharp. In this article we describe the use of the technique to segment MRI images from the brains of healthy subjects and of stroke patients. We apply a number of different active contour models, focusing particularly on methods using a set of levels. Deformable models are a very general tool used in fields as diverse as pattern recognition, animation, geometric modelling and simulation. Active contours are a class of deformable model, first introduced by Kass, that makes it possible to extract key visual features of images, such as the edges of objects or parts of boundaries. When applied to image segmentation, the active contours approach identifies boundaries among objects using intensity and geometric constraints associated with the objects concerned. The basic idea is to gradually deform an initial curve (2D or surface (3D producing the best possible fit with the boundaries of an object. The desired goals are integrated in the formulation of the model which guides the deformation process. In the classical model, the deformation process is based on the minimization of a functional, representing the geometric characteristics of the curve (or surface and the image. This model has drawbacks that can be solved by applying "the geometric model". This model is based on equations describing the evolution of plane curves and surfaces, and their implementation as a set of levels. In this model, the desired contours or surfaces are considered as contours of a function defined over the whole support of the image. Acknowledgment: A big thank you to the neurology department of Grenoble hospital for the images provided and to Catherine Garbay from UJF of Grenoble for her help

  5. Remote Detection of Biological Particles and Chemical Plumes Using UV Fluorescence Lidar

    Science.gov (United States)

    Tiee, J. J.; Hof, D. E.; Karl, R. R.; Martinez, R. J.; Quick, C. R.; Cooper, D. I.; Eichinger, W. E.; Holtkamp, D. B.

    1992-01-01

    A lidar system based on ultraviolet (UV) laser induced fluorescence (LIF) was developed for the remote detection of atmospherically dispersed biological particles and chemical vapors. This UV fluorescence lidar has many potential applications for monitoring environmental pollution, industrial waste emission, agricultural insect control, illicit chemical processing, and military defense operations. The general goal of this work is to investigate the research issues associated with the long range detection and identification of chemicals, e.g. aromatic solvents and chemical precursors, and biological materials, e.g. bacillus thuringiensis (BT) and bacillus globiggi (BG). In the detection of biological particulates, we are particularly interested in extending the detection range of an existing solar-blind 248-nm lidar system. We are investigating the use of longer excitation laser wavelengths (i.e. lambda greater than 280-nm to have more favorable atmospheric light transmission characteristics) for improving detection range to better than 10 km. In the detection of chemical plumes, our main research objectives are to determine how accurately and sensitively a chemical plume can be located at range, and how well spectrally the chemical species can be measured to allow their identification.

  6. Airport detection in remote sensing images: a method based on saliency map.

    Science.gov (United States)

    Wang, Xin; Lv, Qi; Wang, Bin; Zhang, Liming

    2013-04-01

    The detection of airport attracts lots of attention and becomes a hot topic recently because of its applications and importance in military and civil aviation fields. However, the complicated background around airports brings much difficulty into the detection. This paper presents a new method for airport detection in remote sensing images. Distinct from other methods which analyze images pixel by pixel, we introduce visual attention mechanism into detection of airport and improve the efficiency of detection greatly. Firstly, Hough transform is used to judge whether an airport exists in an image. Then an improved graph-based visual saliency model is applied to compute the saliency map and extract regions of interest (ROIs). The airport target is finally detected according to the scale-invariant feature transform features which are extracted from each ROI and classified by hierarchical discriminant regression tree. Experimental results show that the proposed method is faster and more accurate than existing methods, and has lower false alarm rate and better anti-noise performance simultaneously. PMID:24427198

  7. Fast Occlusion and Shadow Detection for High Resolution Remote Sensing Image Combined with LIDAR Point Cloud

    Science.gov (United States)

    Hu, X.; Li, X.

    2012-08-01

    The orthophoto is an important component of GIS database and has been applied in many fields. But occlusion and shadow causes the loss of feature information which has a great effect on the quality of images. One of the critical steps in true orthophoto generation is the detection of occlusion and shadow. Nowadays LiDAR can obtain the digital surface model (DSM) directly. Combined with this technology, image occlusion and shadow can be detected automatically. In this paper, the Z-Buffer is applied for occlusion detection. The shadow detection can be regarded as a same problem with occlusion detection considering the angle between the sun and the camera. However, the Z-Buffer algorithm is computationally expensive. And the volume of scanned data and remote sensing images is very large. Efficient algorithm is another challenge. Modern graphics processing unit (GPU) is much more powerful than central processing unit (CPU). We introduce this technology to speed up the Z-Buffer algorithm and get 7 times increase in speed compared with CPU. The results of experiments demonstrate that Z-Buffer algorithm plays well in occlusion and shadow detection combined with high density of point cloud and GPU can speed up the computation significantly.

  8. fMRI-activation patterns in the detection of concealed information rely on memory-related effects

    OpenAIRE

    Gamer, Matthias; Klimecki, Olga; Bauermann, Thomas; Stoeter, Peter; Vossel, Gerhard

    2009-01-01

    Recent research on potential applications of fMRI in the detection of concealed knowledge primarily ascribed the reported differences in hemodynamic response patterns to deception. This interpretation is challenged by the results of the present study. Participants were required to memorize probe and target items (a banknote and a playing card, each). Subsequently, these items were repeatedly presented along with eight irrelevant items in a modified Guilty Knowledge Test design and participant...

  9. Diffusion-weighted imaging as part of hybrid PET/MRI protocols for whole-body cancer staging: Does it benefit lesion detection?

    International Nuclear Information System (INIS)

    Purpose: Positron emission tomography/magnetic resonance imaging (PET/MRI) requires efficient scan protocols for whole-body cancer staging. The aim of this study was to evaluate if the application of diffusion-weighted MR imaging (DWI) results in a diagnostic benefit for lesion detection in oncologic patients if added to a whole-body [18F]-fluorodesoxyglucose ([18F]-FDG) PET/MRI protocol. Methods: 25 consecutive oncologic patients (16 men, 9 women; age 57 ± 12 years) prospectively underwent whole-body [18F]-FDG-PET/MRI including DWI on a hybrid PET/MRI scanner. A team of two readers assessed [18F]-FDG PET/MRI without DWI for primary tumors and metastases. In a second session, now considering DWI, readers reassessed [18F]-FDG PET/MRI accordingly. Additionally, the lesion-to-background contrast on [18F]-FDG PET and DWI was rated qualitatively (0, invisible; 1, low; 2, intermediate; 3, high). Wilcoxon's signed-rank test was performed to test for differences in the lesion-to-background contrast. Results: 49 lesions were detected in 16 patients (5 primaries, 44 metastases). All 49 lesions were concordantly detected by [18F]-FDG PET/MRI alone and [18F]-FDG PET/MRI with DWI. The lesion-to-background contrast on DWI compared to [18F]-FDG PET was rated lower in 22 (44.9%) of 49 detected lesions resulting in a significantly higher lesion-to-background contrast on [18F]-FDG PET compared to DWI (P = 0.001). Conclusions: DWI as part of whole-body [18F]-FDG PET/MRI does not benefit lesion detection. Given the necessity to optimize imaging protocols with regard to patient comfort and efficacy, DWI has to be questioned as a standard tool for whole-body staging in oncologic PET/MRI

  10. Detecting moisture status of pecan orchards and the potential of remotely-sensed surface reflectance data

    Science.gov (United States)

    Othman, Yahia Abdelrahman

    Demand for New Mexico's limited water resources coupled with periodic drought has increased the need to schedule irrigation of pecan orchards based on tree water status. The overall goal of this research was to develop advanced tree water status sensing techniques to optimize irrigation scheduling of pecan orchards. To achieve this goal, I conducted three studies in the La Mancha and Leyendecker orchards, both mature pecan orchards located in the Mesilla Valley, New Mexico. In the first study, I screened leaf-level physiological changes that occurred during cyclic irrigation to determine parameters that best represented changes in plant moisture status. Then, I linked plant physiological changes to remotely-sensed surface reflectance data derived from Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM+). In the second study, I assessed the impact of water deficits that developed during the flood irrigation dry-down cycles on photosynthesis (A) and gas exchange and established preliminary water deficit thresholds of midday stem water potential (Psi smd) critical to A and gas exchange of pecans. In a third study, I investigated whether hyperspectral data obtained from a handheld spectroradiometer and multispectral remotely-sensed data derived from Landsat 7 ETM+ and Landsat 8 Operational Land Imager (OLI) could detect moisture status in pecans during cyclic flood irrigations. I conducted the first study simultaneously in both orchards. Leaf-level physiological responses and remotely-sensed surface reflectance data were collected from trees that were either well watered or in water deficit. Midday stem water potential was the best leaf-level physiological response to detect moisture status in pecans. Multiple linear regression between Psismd and vegetation indices revealed a significant relationship (R 2 = 0.54) in both orchards. Accordingly, I concluded that remotely-sensed multispectral data form Landsat TMETM+ holds promise for detecting the moisture status of pecans. I conducted the second study simultaneously on the same mature pecan orchards that were used in the first study. Photosynthesis and gas exchange were assessed at Psismd of -0.4 to -2.0 MPa. This study established preliminary values of Psismd that significantly impacted A and gas exchange of field-grown pecans. I recommended that pecan orchards be maintained at Psismd that ranged between -0.80 to -0.90 MPa to prevent significant reductions in A and gas exchange. Broken-line analysis revealed that A remained relatively constant when Psismd was above -0.65 MPa. Conversely, there was linear positive relationship between Psi smd and A when Psismd was less than -0.65 MPa. In the third study, again conducted on both orchards, leaf-level physiological measurements and remotely-sensed data were taken at Psismd levels of -0.40 to -0.85 MPa, -0.95 to -1.45 MPa , and -1.5 to -2.0 MPa. Hyperspectral reflectance indices (from handheld spectroradiometer) detected moisture status in pecan trees better than multispectral reflectance indices (from Landsat ETM+OLI). Vegetation moisture index-I (VMI-I) and vegetation moisture index-II (VMI-II) significantly correlated with Psismd (VMI-I, 0.88 > r > 0.87; VMI-II, -0.68 > r > -0.65). Vegetation moisture index-I Boxplot analysis did not clearly separate moderate water status (-0.95 to -1.45 MPa) at La Mancha, but did so at Leyendecker. However, multispectral reflectance indices had a limited capacity to precisely detect the moderate water status at both orchards (the time when A declined by 15 - 40 %). Given that Psi smd of-0.90 to -1.45 MPa is a critical range for irrigating pecans, I concluded that vegetation indices derived only from hyperspectral reflectance data could be used to detect plant physiological responses that are related to plant water status.

  11. The STIR sequence. Comparison with other MRI sequences and bone scan in the detection of vertebral bone metastases

    International Nuclear Information System (INIS)

    A prospective MRI study of the spine comparing short inversion-recovery sequences (STIR) - one the features of which is to potentiate the contrast of both long T1 and T2 sequences - with other spin echo and/or gradient echo MRI sequences, was conducted in 20 patients with suspected vertebral metastases. The features of the signal on STIR sequences were initially defined in 14 healthy volunteers. In the patients, the various MRI sequences were also compared to each other and to standard x-rays and bone scans. The sensitivity of detection of vertebral metastases did not appear to be significantly different between T1 sequences and the STIR sequence. However, these two sequences appeared to be significantly more sensitive than T2-weighted sequences. The STIR sequences therefore appears to be a logical complement to T1-weighted sequences in the detection of vertebral secondaries. This sequence even appears to be superior in the following situations: investigation of the cervical vertebrae, follow-up of irradiated bone, early detection of periduritis and lesions of the posterior arch

  12. Cloud Detection Method Based on Feature Extraction in Remote Sensing Images

    Science.gov (United States)

    Changhui, Y.; Yuan, Y.; Minjing, M.; Menglu, Z.

    2013-05-01

    In remote sensing images, the existence of the clouds has a great impact on the image quality and subsequent image processing, as the images covered with clouds contain little useful information. Therefore, the detection and recognition of clouds is one of the major problems in the application of remote sensing images. Present there are two categories of method to cloud detection. One is setting spectrum thresholds based on the characteristics of the clouds to distinguish them. However, the instability and uncertainty of the practical clouds makes this kind of method complexity and weak adaptability. The other method adopts the features in the images to identify the clouds. Since there will be significant overlaps in some features of the clouds and grounds, the detection result is highly dependent on the effectiveness of the features. This paper presented a cloud detection method based on feature extraction for remote sensing images. At first, find out effective features through training pattern, the features are selected from gray, frequency and texture domains. The different features in the three domains of the training samples are calculated. Through the result of statistical analysis of all the features, the useful features are picked up to form a feature set. In concrete, the set includes three feature vectors, respectively, the gray feature vector constituted of average gray, variance, first-order difference, entropy and histogram, the frequency feature vector constituted of DCT high frequency coefficient and wavelet high frequency coefficient, and the texture feature vector constituted of the hybrid entropy and difference of the gray-gradient co-occurrence matrix and the image fractal dimension. Secondly, a thumbnail will be obtained by down sampling the original image and its features of gray, frequency and texture are computed. Last but not least, the cloud region will be judged by the comparison between the actual feature values and the thresholds determined by the sample training process. Experimental results show that the clouds and ground objects can be separated efficiently, and our method can implement rapid clouds detection and cloudiness calculation.

  13. Lake Storage Change Automatic Detection by Multi-source Remote Sensing without Underwater Terrain Data

    Directory of Open Access Journals (Sweden)

    ZHU Changming

    2015-03-01

    Full Text Available Focusing on lake underwater terrain unknown and dynamic storage that is difficult to obtain by the traditional methods, a new method is proposed for lake dynamic storage estimation by multi-source and multi-temporal remote sensing without underwater terrain data. The details are as follows. Firstly, extraction dynamic lake boundary through steps by steps adaptive iteration water body detection algorithm from multi-temporal remote sensing imagery. And then, retrieve water level information from ICESat GLAS laser point data. Thirdly, comprehensive utilizing lake area and elevation data, the lake boundary is converted to contour of water by the water level is assigned to the lake boundary line, according to the time and water level information. Fourthly, through the contour line construction TIN (triangulated irregular network model and Kriging interpolation, it is gotten that the simulated three-dimensional lake digital elevation model. Finally, on the basis of simulated DEM, it is calculated that the dynamic lake volume, lake area distribution and water level information. The Bosten lake is selected as a case studying to verify the algorithm. The area and dynamic water storage variations of Bosten lake are detected since 2000. The results show that, the maximum error is 2.21× 108 m3, the minimum error is 0.00002× 108 m3, the average error is 0.044×108 m3, the root mean square is 0.59 and the correlation coefficient reached 0.99.

  14. Protein Remote Homology Detection and Fold Recognition based on Features Extracted from Frequency Profiles

    Directory of Open Access Journals (Sweden)

    Lei Lin

    2011-02-01

    Full Text Available Protein remote homology detection and fold recognition are central problems in bioinformatics. Currently, discriminative methods based on support vector machine (SVM are the most effective and accurate methods for solving these problems. The performance of SVM depends on the method of protein vectorization, so a suitable representation of the protein sequence is a key step for the SVM-based methods. In this paper, two kinds of profile-level building blocks of proteins, binary profiles and N-nary profiles, have been presented, which contain the evolutionary information of the protein sequence frequency profile. The protein sequence frequency profiles calculated from the multiple sequence alignments outputted by PSI-BLAST are converted into binary profiles or N-nary profiles. The protein sequences are transformed into fixed-dimension feature vectors by the occurrence times of each binary profile or N-nary profile and then the corresponding vectors are inputted to support vector machines. The latent semantic analysis (LSA model, an efficient feature extraction algorithm, is adopted to further improve the performance of our methods. Experiments with protein remote homology detection and fold recognition show that the methods based on profile-level building blocks give better results compared to related methods.

  15. Motif kernel generated by genetic programming improves remote homology and fold detection

    Directory of Open Access Journals (Sweden)

    Sætrom Pål

    2007-01-01

    Full Text Available Abstract Background Protein remote homology detection is a central problem in computational biology. Most recent methods train support vector machines to discriminate between related and unrelated sequences and these studies have introduced several types of kernels. One successful approach is to base a kernel on shared occurrences of discrete sequence motifs. Still, many protein sequences fail to be classified correctly for a lack of a suitable set of motifs for these sequences. Results We introduce the GPkernel, which is a motif kernel based on discrete sequence motifs where the motifs are evolved using genetic programming. All proteins can be grouped according to evolutionary relations and structure, and the method uses this inherent structure to create groups of motifs that discriminate between different families of evolutionary origin. When tested on two SCOP benchmarks, the superfamily and fold recognition problems, the GPkernel gives significantly better results compared to related methods of remote homology detection. Conclusion The GPkernel gives particularly good results on the more difficult fold recognition problem compared to the other methods. This is mainly because the method creates motif sets that describe similarities among subgroups of both the related and unrelated proteins. This rich set of motifs give a better description of the similarities and differences between different folds than do previous motif-based methods.

  16. Remote sensing of debris-covered glaciers: Change detection and analysis using multiple sensors

    Science.gov (United States)

    Ahn, Y.; Huh, K.; Mark, B. G.; La Frenierre, J.; Gulley, J. D.; Park, K.

    2013-12-01

    Debris-cover can insulate glaciers and hinder surface melting, but also challenges accurate assessment of change detection and subsequent risk evaluation of outburst floods from moraine-dammed supra-glacial lakes that endanger downstream inhabitants. These events have been predicted to increase frequency along with the coverage of debris as warming accelerates. Enhanced monitoring capability from optical air and space-borne sensors has improved the detection of changes in surface-derived characteristics such as areal and volumetric fluctuations as well as glacier velocity over debris-covered glaciers, improving the accuracy of geometric and temporal resolutions in hydrological analysis. In this study we present case studies from Nepal, Peru and Ecuador focusing on: 1) time series of debris-coverage and moraine-dammed lakes; and 2) the relationship of remotely sensed observable quantities from different sensors such as aerial photographs, ASTER, Landsat imagery and Airborne/Terrestrial Laser Scanner.

  17. Distributed Sensor Particles for Remote Fluorescence Detection of Trace Analytes: UXO/CW

    Energy Technology Data Exchange (ETDEWEB)

    SINGH, ANUP K.; GUPTA, ALOK; MULCHANDANI, ASHOK; CHEN, WILFRED; BHATIA, RIMPLE B.; SCHOENIGER, JOSEPH S.; ASHLEY, CAROL S.; BRINKER, C. JEFFREY; HANCE, BRADLEY G.; SCHMITT, RANDAL L.; JOHNSON, MARK S.; HARGIS JR., PHILIP J.; SIMONSON, ROBERT J.

    2001-11-01

    This report summarizes the development of sensor particles for remote detection of trace chemical analytes over broad areas, e.g residual trinitrotoluene from buried landmines or other unexploded ordnance (UXO). We also describe the potential of the sensor particle approach for the detection of chemical warfare (CW) agents. The primary goal of this work has been the development of sensor particles that incorporate sample preconcentration, analyte molecular recognition, chemical signal amplification, and fluorescence signal transduction within a ''grain of sand''. Two approaches for particle-based chemical-to-fluorescence signal transduction are described: (1) enzyme-amplified immunoassays using biocompatible inorganic encapsulants, and (2) oxidative quenching of a unique fluorescent polymer by TNT.

  18. A Remote Sensor for Detecting Methane Based on Palladium-Decorated Single Walled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Guomin Li

    2013-07-01

    Full Text Available The remote detection of the concentration of methane at room temperature is performed by a sensor that is configured by the combination of radio frequency identification (RFID, and functionalized carbon nanotubes (CNTs. The proposed sensor is schemed as a thin film RFID tag in a polyethylene substrate, on which a metal trace dipole, a metal trace T impedance matching networks, a 0.5 µm-CMOS RF/DC rectifier chipset and a sensor head of palladium-decorated single walled carbon nanotubes (Pd-SWCNTs are surface mounted in cascade. The performances of the sensor are examined and described by the defined parameters of the received signal strength index (RSSI and the comparative analog identifier (?AID. Results validate the sensor’s ability to detect molecules of methane at room temperature, showing that the RSSI can increase 4 dB and the ?AID can increase 3% in response to methane concentrations ranging from zero to 100 ppm.

  19. Distributed Sensor Particles for Remote Fluorescence Detection of Trace Analytes: UXO/CW; TOPICAL

    International Nuclear Information System (INIS)

    This report summarizes the development of sensor particles for remote detection of trace chemical analytes over broad areas, e.g residual trinitrotoluene from buried landmines or other unexploded ordnance (UXO). We also describe the potential of the sensor particle approach for the detection of chemical warfare (CW) agents. The primary goal of this work has been the development of sensor particles that incorporate sample preconcentration, analyte molecular recognition, chemical signal amplification, and fluorescence signal transduction within a ''grain of sand''. Two approaches for particle-based chemical-to-fluorescence signal transduction are described: (1) enzyme-amplified immunoassays using biocompatible inorganic encapsulants, and (2) oxidative quenching of a unique fluorescent polymer by TNT

  20. Multifunctional fiber-optic microwave links based on remote heterodyne detection

    DEFF Research Database (Denmark)

    Gliese, Ulrik Bo; Nielsen, Torben Nørskov; Nielsen, Søren Nørskov; Stubkjær, Kristian

    1998-01-01

    fiber-optic microwave links. The resulting links are inherently transparent. As opposed to DD links, RHD links can perform radio-system functionalities such as modulation and frequency conversion in addition to transparency. All of these three functionalities are presented and experimentally...... carrier to a 9-GHz carrier with penalty-free transmission over 25 km of optical fiber. Finally, the transparent link transmits a standard FM video 7.6-GHz radio-link signal over 25 km of optical fiber without measurable distortion......The multifunctionality of microwave links based on remote heterodyne detection (RHD) of signals from a dual-frequency laser transmitter is discussed and experimentally demonstrated in this paper. Typically, direct detection (DD) in conjunction with optical intensity modulation is used to implement...

  1. Fluid motion and solute distribution around sinking aggregates II : Implications for remote detection by colonizing zooplankters

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Thygesen, Uffe Høgsbro

    2001-01-01

    Marine snow aggregates are colonized by copepods, and encounter rates inferred from observed abundances of colonizers are high. We examined the potential for hydromechanical and chemical remote detection. The fluid disturbance generated by a sinking aggregate was described by solving the Navier...... account for the observed abundances of colonizers. We next solved the advection-diffusion equation to describe the chemical trail left by a leaking and sinking aggregate. The plume is long and slender and may be detected by a horizontally cruising copepod. From the model of the plume and literature- based...... estimates of size-dependent aggregate leakage rates of amino acids, we estimate that a threshold sensitivity to amino acids of 0.4 x 10(-7) M is required to account for observed abundances of colonizers. This is consistent with knowledge of the amino acid concentrations needed to elicit behavioral responses...

  2. A method of detecting land use change of remote sensing images based on texture features and DEM

    Science.gov (United States)

    Huang, Dong-ming; Wei, Chun-tao; Yu, Jun-chen; Wang, Jian-lin

    2015-12-01

    In this paper, a combination method, between the neural network and textures information, is proposed to remote sensing images classification. The methodology involves an extraction of texture features using the gray level co-occurrence matrix and image classification with BP artificial neural network. The combination of texture features and the digital elevation model (DEM) as classified bands to neural network were used to recognized different classes. This scheme shows high recognition accuracy in the classification of remote sensing images. In the experiments, the proposed method was successfully applied to remote sensing image classification and Land Use Change Detection, in the meanwhile, the effectiveness of the proposed method was verified.

  3. Mixture-Tuned, Clutter Matched Filter for Remote Detection of Subpixel Spectral Signals

    Science.gov (United States)

    Thompson, David R.; Mandrake, Lukas; Green, Robert O.

    2013-01-01

    Mapping localized spectral features in large images demands sensitive and robust detection algorithms. Two aspects of large images that can harm matched-filter detection performance are addressed simultaneously. First, multimodal backgrounds may thwart the typical Gaussian model. Second, outlier features can trigger false detections from large projections onto the target vector. Two state-of-the-art approaches are combined that independently address outlier false positives and multimodal backgrounds. The background clustering models multimodal backgrounds, and the mixture tuned matched filter (MT-MF) addresses outliers. Combining the two methods captures significant additional performance benefits. The resulting mixture tuned clutter matched filter (MT-CMF) shows effective performance on simulated and airborne datasets. The classical MNF transform was applied, followed by k-means clustering. Then, each cluster s mean, covariance, and the corresponding eigenvalues were estimated. This yields a cluster-specific matched filter estimate as well as a cluster- specific feasibility score to flag outlier false positives. The technology described is a proof of concept that may be employed in future target detection and mapping applications for remote imaging spectrometers. It is of most direct relevance to JPL proposals for airborne and orbital hyperspectral instruments. Applications include subpixel target detection in hyperspectral scenes for military surveillance. Earth science applications include mineralogical mapping, species discrimination for ecosystem health monitoring, and land use classification.

  4. Comparison of abdominal MRI with diffusion-weighted imaging to 68Ga-DOTATATE PET/CT in detection of neuroendocrine tumors of the pancreas

    International Nuclear Information System (INIS)

    The aim of the study was to evaluate contrast-enhanced MRI, diffusion-weighted MRI (DW MRI), and 68Ga-DOTATATE positron emission tomography (PET)/CT in the detection of intermediate to well-differentiated neuroendocrine tumors (NET) of the pancreas. Eighteen patients with pathologically proven pancreatic NET who underwent MRI including DW MRI and PET/CT within 6 weeks of each other were included in this retrospective study. Two radiologists evaluated T2-weighted (T2w), T2w + DW MRI, T2w + contrast-enhanced T1-weighted (CE T1w) MR images, and PET/CT for NET detection. The sensitivity and level of diagnostic confidence were compared among modalities using McNemar's test and a Wilcoxon signed rank test. Apparent diffusion coefficients (ADC) of pancreatic NETs and normal pancreatic tissue were compared with Student's t test. Of the NETs, 8/23 (34.8 %) and 9/23 (39.1 %) were detected on T2w images by observers 1 and 2, respectively. Detection rates improved significantly by combining T2w images with DW MRI (observer 1: 14/23 = 61 %; observer 2: 15/23 = 65.2 %; p -3 mm2/s) was statistically significantly lower than that of normal pancreatic tissue (1.48 ± 0.39 x 10-3 mm2/s). DW MRI is a valuable adjunct to T2w imaging and comparable to CE T1w imaging in pancreatic NET detection, quantitatively differentiating between NET and normal pancreatic tissue with ADC measurements. 68Ga-DOTATATE PET/CT is more sensitive than MRI in the detection of pancreatic NET. (orig.)

  5. Three-dimensional accurate detection of lung emphysema in rats using ultra-short and zero echo time MRI.

    Science.gov (United States)

    Bianchi, Andrea; Tibiletti, Marta; Kjørstad, Åsmund; Birk, Gerald; Schad, Lothar R; Stierstorfer, Birgit; Rasche, Volker; Stiller, Detlef

    2015-11-01

    Emphysema is a life-threatening pathology that causes irreversible destruction of alveolar walls. In vivo imaging techniques play a fundamental role in the early non-invasive pre-clinical and clinical detection and longitudinal follow-up of this pathology. In the present study, we aimed to evaluate the feasibility of using high resolution radial three-dimensional (3D) zero echo time (ZTE) and 3D ultra-short echo time (UTE) MRI to accurately detect lung pathomorphological changes in a rodent model of emphysema.Porcine pancreas elastase (PPE) was intratracheally administered to the rats to produce the emphysematous changes. 3D ZTE MRI, low and high definition 3D UTE MRI and micro-computed tomography images were acquired 4 weeks after the PPE challenge. Signal-to-noise ratios (SNRs) were measured in PPE-treated and control rats. T2 * values were computed from low definition 3D UTE MRI. Histomorphometric measurements were made after euthanizing the animals. Both ZTE and UTE MR images showed a significant decrease in the SNR measured in PPE-treated lungs compared with controls, due to the pathomorphological changes taking place in the challenged lungs. A significant decrease in T2 * values in PPE-challenged animals compared with controls was measured using UTE MRI. Histomorphometric measurements showed a significant increase in the mean linear intercept in PPE-treated lungs. UTE yielded significantly higher SNR compared with ZTE (14% and 30% higher in PPE-treated and non-PPE-treated lungs, respectively).This study showed that optimized 3D radial UTE and ZTE MRI can provide lung images of excellent quality, with high isotropic spatial resolution (400 µm) and SNR in parenchymal tissue (>25) and negligible motion artifacts in freely breathing animals. These techniques were shown to be useful non-invasive instruments to accurately and reliably detect the pathomorphological alterations taking place in emphysematous lungs, without incurring the risks of cumulative radiation exposure typical of micro-computed tomography. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26403226

  6. Prostate cancer transrectal HIFU ablation: detection of local recurrences using T2-weighted and dynamic contrast-enhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Rouviere, Olivier; Lyonnet, Denis [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Urinary and Vascular Radiology, Lyon (France); Universite de Lyon, Lyon (France); Universite de Lyon 1, Faculte de medecine Lyon Nord, Lyon (France); Inserm, U556, Lyon (France); Girouin, Nicolas; Glas, Ludivine; Ben Cheikh, Alexandre [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Urinary and Vascular Radiology, Lyon (France); Universite de Lyon, Lyon (France); Universite de Lyon 1, Faculte de medecine Lyon Nord, Lyon (France); Gelet, Albert [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Urology, Lyon (France); Inserm, U556, Lyon (France); Mege-Lechevallier, Florence [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Pathology, Lyon (France); Rabilloud, Muriel [Hospices Civils de Lyon, Department of Biostatistics, Lyon (France); Universite de Lyon 1, UMR CNRS, Laboratoire Biostatistiques-Sante, Pierre-Benite (France); Chapelon, Jean-Yves [Inserm, U556, Lyon (France)

    2010-01-15

    The objective was to evaluate T2-weighted (T2w) and dynamic contrast-enhanced (DCE) MRI in detecting local cancer recurrences after prostate high-intensity focused ultrasound (HIFU) ablation. Fifty-nine patients with biochemical recurrence after prostate HIFU ablation underwent T2-weighted and DCE MRI before transrectal biopsy. For each patient, biopsies were performed by two operators: operator 1 (blinded to MR results) performed random and colour Doppler-guided biopsies (''routine biopsies''); operator 2 obtained up to three cores per suspicious lesion on MRI (''targeted biopsies''). Seventy-seven suspicious lesions were detected on DCE images (n=52), T2w images (n=2) or both (n=23). Forty patients and 41 MR lesions were positive at biopsy. Of the 36 remaining MR lesions, 20 contained viable benign glands. Targeted biopsy detected more cancers than routine biopsy (36 versus 27 patients, p=0.0523). The mean percentages of positive cores per patient and of tumour invasion of the cores were significantly higher for targeted biopsies (p<0.0001). The odds ratios of the probability of finding viable cancer and viable prostate tissue (benign or malignant) at targeted versus routine biopsy were respectively 3.35 (95% CI 3.05-3.64) and 1.38 (95% CI 1.13-1.63). MRI combining T2-weighted and DCE images is a promising method for guiding post-HIFU biopsy towards areas containing recurrent cancer and viable prostate tissue. (orig.)

  7. Application and validation of spatial mixture modelling for the joint detection-estimation of brain activity in fMRI.

    OpenAIRE

    Vincent, Thomas; Ciuciu, Philippe; Idier, Jérôme

    2007-01-01

    Within-subject analysis in event-related functional Magnetic Resonance Imaging (fMRI) first relies on (i) a detection step to localize which parts of the brain are activated by a given stimulus type, and second on (ii) an estimation step to recover the temporal dynamics of the brain response. Recently, a Bayesian detection-estimation approach that jointly addresses (i)-(ii) has been proposed in [1]. This work is based on an independent mixture model (IMM) and provides both a spatial activity ...

  8. Stress cine MRI for detection of coronary artery disease; Stress-Cine-MRT zur Primaeridagnostik der koronaren Herzkrankheit

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, T.; Hofer, U.; Schild, H. [Bonn Univ. (Germany). Radiologische Klinik; Omran, H. [Medizinische Universitaetsklinik II Bonn (Germany)

    2002-05-01

    Stress testing is the cornerstone in the diagnosis of patients with suspected coronary artery disease (CAD). Stress echocardiography has become a well-established modality for the detection of ischemia-induced wall motion abnormalities. However, display and reliable interpretation of stress echocardiography studies are user-dependent, the test reproducibility is low, and 10 to 15% of patients yield suboptimal or non-diagnostic images. Due to its high spatial and contrast resolution, MRI is known to permit an accurate determination of left ventricular function and wall thickness at rest. Early stress MRI studies provided promising results with respect to the detection of CAD. However, the clinical impact was limited due to long imaging time and problematic patient monitoring in the MRI environment. Recent technical improvements - namely ultrafast MR image acquisition - led to a significant reduction of imaging time and improved patient safety. Stress can be induced by physical exercise or pharmacologically by administration of a beta{sub 1}-agonist (dobutamine) or vasodilatator (dipyridamole and adenosine). The best developed and most promising stress MRI technique is a high-dose dobutamine/atropine stress protocol (10, 20, 30, 40 {mu}g/kg/min; optionally 0.25-mg fractions of atropine up to maximal dose 1 mg). Severe complications (myocardial infarction, ventricular fibrillation and sustained tachycardia, cardiogenic shock) may be expected in 0.25% of patients. Currently, data of three high-dose dobutamine stress MRI studies are available, revealing a good sensitivity (83 - 87%) and specificity (83 - 86%) in the assessment of CAD. The direct comparison between echocardiography and MRI for the detection of stress-induced wall motion abnormalities yielded better results for dobutamine-MRI in terms of sensitivity (86.2% vs. 74.3%; p < 0.05) and specificity (85.7% vs. 69.8% p < 0.05) as compared to dobutamine stress echocardiography. The superior results of MRI can mainly be explained by the better image quality with sharp delineation of the endocardial and epicardial borders. Currently, stress MRI is already a realistic clinical alternative for the non-invasive assessment of CAD in patients with impaired image quality in echocardiography. (orig.) [German] Belastungsuntersuchungen sind einer der wesentlichen Pfeiler der nicht-invasiven Diagnostik der koronaren Herzkrankheit (KHK). Die Stress-Cine-Magnetresonanztomographie (Stress-MRT) beruht wie die Stressechokardiographie auf dem direkten Nachweis ischaemieinduzierter Wandbewegungsstoerungen. Ihr Einsatz bei kardialen Belastungsuntersuchungen wurde bisher vor allem durch die langen Untersuchungszeiten und die limitierten Ueberwachungsmoeglichkeiten der Patienten eingeschraenkt. Erst seit kurzem wurden durch technische Weiterentwicklungen (insbesondere ultraschnelle k-Raum-segmentierte Sequenzen) die wesentlichen Rahmenbedingungen fuer eine klinisch praktikable kardiale MRT-Belastungsdiagnostik geschaffen. Als Stress-Induktoren koennen physikalische (Fahrradergometrie) und pharmakologische Belastungsverfahren ({beta}{sub 1}-Mimetika [Dobutamin] oder Vasodilatatoren [Dipyridamol, Adenosin]) eingesetzt werden. Insbesondere seit der Etablierung von Hochdosis-Protokollen mit fakultativer Atropingabe wird die Belastung mit Dobutamin bei der Stress-MRT zum Nachweis einer KHK (Sensitivitaet: 83 - 87%; Spezifitaet: 83 - 86%) von den meisten Arbeitsgruppen favorisiert. Schwerere Komplikationen treten in 0,25% der Faelle auf. Im direkten Vergleich zeigte sich die Dobutamin-Stress-MRT aufgrund der besseren Bildqualitaet der Dobutamin-Stressechokardiographie ueberlegen (Sensitivitaet: 86,2% vs. 74,3%, p < 0,05; Spezifitaet: 85,7% vs. 69,8%, p < 0,05). Die Stress-MRT ist bereits zum jetzigen Zeitpunkt eine realistische - in der Routinediagnostik anwendbare - Alternative zur Stressechokardiographie. Vom Einsatz der Stress-MRT profitieren zur Zeit v.a. Patienten, bei denen aufgrund grundsaetzlich schlechter Schallbarkeit mit hoher Wahrscheinlichkeit von nicht oder nur eingeschraenkt beurteilbaren stressechokardiographischen Untersuchungen auszugehen ist. (orig.)

  9. Whole-heart dipyridamole stress first-pass myocardial perfusion MRI for the detection of coronary artery disease

    International Nuclear Information System (INIS)

    A whole-heart coverage MRI sequence, which employs a hybrid of fast gradient echo and echo planar acquisition imaging (FastCard EchoTrain), has recently been developed. Using this sequence, a first-pass myocardial perfusion MRI was shown to be a good non-invasive modality for detecting coronary artery disease (CAD) in a clinical setting. In addition, the clinical usefulness of delayed enhanced MRI has recently been reported. The objectives of this study were to investigate the accuracy of dipyridamole stress first-pass myocardial perfusion MRI for diagnosing CAD (> 50% stenosis) and to clarify whether additional delayed enhancement MRI has any clinical significance. We performed first-pass myocardial perfusion MRI in 102 consecutive patients (66±9 years old) suspected to have CAD or new lesions in patients with well-documented prior myocardial infarction (MI). Using a 1.5 T cardiac MR imager (GE CV/i), eight short axis MR images of the left ventricle were acquired by injecting gadolinium (0.1 mmol/kg) under dipyridamole infusion stress (0.56 mg/kg). Fifteen minutes later, aminophylline (250 mg) was injected and first-pass perfusion MRI was repeated in the resting state in order to evaluate both the presence of perfusion defect and delayed enhancement. The presence of perfusion defect and delayed enhancement was determined based on a visual qualitative analysis by the agreement of two separate readers who were blinded to any clinical information. Based on the stress and rest findings, no defect, reversible defect, or fixed defect with or without delayed enhancement was recorded in any patient. The MR findings revealed 76 CAD patients, including 24 MI patients with new lesions and 26 patients without CAD on coronary angiography. The presence of stress perfusion defect had a 93% sensitivity and an 85% specificity for diagnosing CAD. A fixed defect showed an 86% sensitivity and a 66% specificity for diagnosing a prior MI. Patients with a fixed defect with delayed enhancement had more significant stenosis in the infarct related artery than in those without any enhancement (11/26 vs 15/20, P<0.05). (author)

  10. Comparison of Technetium-99m-MIBI imaging with MRI for detection of spine involvement in patients with multiple myeloma

    International Nuclear Information System (INIS)

    Recently, radiopharmaceutical scanning with Tc-99m-MIBI was reported to depict areas with active bone disease in multiple myeloma (MM) with both high sensitivity and specificity. This observation was explained by the uptake of Tc-99m-MIBI by neoplastic cells. The present investigation evaluates whether Tc-99m-MIBI imaging and magnetic resonance imaging (MRI) perform equally well in detecting myelomatous bone marrow lesions. In 21 patients with MM, MRIs of the vertebral region TH12 to S1 and whole body scans with Tc-99m-MIBI were done. Tc-99m-MIBI scanning missed bone marrow infiltration in 43 of 87 vertebrae (50.5%) in which MRI showed neoplastic bone marrow involvement. In patients with disease stage I+II, Tc-99m-MIBI scanning was negative in all of 24 vertebrae infiltrated according to MRI. In patients with disease stage III, Tc-99m-MIBI scanning detected 44 of 63 (70%) vertebrae involved by neoplastic disease. Tc-99m-MIBI scanning underestimated the extent of myelomatous bone marrow infiltration in the spine, especially in patients with low disease stage

  11. Does low-field dedicated extremity MRI (E-MRI) reliably detect bone erosions in rheumatoid arthritis? : A comparison of two different E-MRI units and conventional radiography with high-resolution CT scanning

    DEFF Research Database (Denmark)

    Duer-Jensen, A; Ejbjerg, B

    2009-01-01

    OBJECTIVES: To compare the ability of two different E-MRI units and conventional radiography (CR) to identify bone erosions in rheumatoid arthritis (RA) metacarpophalangeal (MCP) and wrist joints with CT scanning as the standard reference method. METHODS: 20 patients with RA and 5 controls underwent CR, CT and two E-MRI examinations (Esaote Biomedica Artoscan and MagneVu MV1000) of one hand during a 2-week period. In all modalities, each bone of the wrist and MCP joints was blindly evaluated for erosions. MagneVu images were also assessed for the proportion of each bone being visualised. RESULTS: 550 bones were examined. CT, Artoscan, MagneVu and CR detected 188, 116, 55 and 45 bones with erosions, respectively. The majority were located in the carpal bones. The sensitivity of the Artoscan for detecting erosions was higher than that of the MagneVu and CR (MCP joints: 0.68, 0.54 and 0.57, respectively; wrists: 0.50, 0.23 and 0.29). Corresponding specificities for detecting erosions were 0.94, 0.93 and 0.99, respectively, in the MCP joints and 0.92, 0.98 and 0.98 in the wrist. The MagneVu allowed visualisation of 1.5 cm of the ventral-dorsal diameter of the bone. In the wrist, 31.6% of bones were visualised entirely and 37.9% of bones were 67-99% visualised. In MCP joints, 84.2% of bones were visualised entirely and 15.8% of bones were 67-99% visualised. CONCLUSION: With CT as the reference method for detecting erosions in RA hands, the Artoscan showed higher sensitivity than the MagneVu and CR. All imaging modalities had high specificities. The better performance of the Artoscan should be considered when selecting an imaging method in RA.

  12. Coal fires in Northwest China. Detection, monitoring, and prediction using remote sensing data

    International Nuclear Information System (INIS)

    Coal fires in China occur within a region that stretches over 5,000 km in the east- western part and 750 km. in the north-southern part. These fires cause an economic and environmental threat by making a significant contribution to the global CO2 budget. The studies made in this thesis can be divided into two parts. Part one is based on field work and laboratory analysis that includes the dating of the paleo coal fires; part two concerns remote sensing applications for the active coal fires. In Chapter 2, the evolution of the paleo coal fires in Toutunhe and Xinjiang areas are studied. Several age groups of burnt rock have been recognized and their relationships with the river terraces will be discussed. The causes of the paleo coal fires are addressed, and the areas of coal fires with different ages have been dated. In Chapter 3, the physical basis of thermal infrared remote sensing for the detection and measurement of coal fires are addressed with an emphasis on the spatial, spectral, and radiometric resolution. In Chapter 4, a method to reduce the effect of solar heating, the main factor of confusion when investigating the thermal anomalies of coal fires, is discussed with the help of a DEM. In Chapter 5, as the coal fires normally occupy only part of one pixel of the Landsat TM thermal channel data, the capability of sub pixel coal fire detection is addressed. In Chapter 6, the airborne data from different wavelengths acquired at different times are studied to analyze the spatial thermal characteristics of the coal fires. Spreading direction and different types of coal fires are studied. Chapter 7 presents, based on multi-sensor data fusion techniques, a hierarchical methodology for detection and monitoring of the coal fires. 120 refs

  13. Applying remote sensing and GIS for chimpanzee habitat change detection, behaviour and conservation

    Science.gov (United States)

    Pintea, Lilian

    Chimpanzees (Pan troglodytes), our closest living relatives, are declining alarmingly in abundance and distribution all across Africa. Clearing of forests and woodlands has one of the most rapid and devastating impacts, leaving chimpanzees in isolated, small populations that face edge effects and elevated risk of extinction. Satellite imagery could be a powerful tool to map chimpanzee habitats and threats at the landscape scale even in the most remote, difficult to access areas. However, few applications exist to demonstrate how remote sensing methods can be used in Africa for chimpanzee research and conservation in practice. In chapter one, I investigate the use of Landsat MSS and ETM+ satellite imagery to monitor dry tropical forests and miombo woodlands change between 1972-1999 inside and outside Gombe National Park, Tanzania. I show that canopy cover increased in the northern and middle parts of the park but with severe canopy loss outside protected area. Deforestation has had unequal effects on the three chimpanzee communities inside the park. The Kasekela chimpanzees have been least affected by canopy loss outside the park. In contrast, the Mitumba and Kalande communities have likely lost key range areas. In chapter two, I use 25 years of data on Gombe chimpanzees to investigate to what extent vegetation variables detected from multi-temporal satellite images can be applied to understand changes in chimpanzee feeding and party size. NDVI positively correlated with the time chimpanzees spent feeding but had no affect on the average number of adult males in the party. Instead the number of males in the party increased with proximity to hostile neighboring communities. In chapter three, I use Landsat and SPOT satellite imagery as the basis for Threat Reduction Assessment to evaluate conservation outcomes of a ten year community based conservation project in Tanzania. The findings suggest that the remote sensing methods applied in this study could provide new exciting prospects for monitoring chimpanzee habitats, socioecological research and a baseline to measure our conservation success.

  14. Intrusion detection capabilities of smart video: Collaborative efforts to improve remote monitoring for safeguards surveillance

    Energy Technology Data Exchange (ETDEWEB)

    Kadner, S.P.; Ondrik, M. [Aquila Technologies Group, Albuquerque, NM (United States); Reisman, A. [Brookhaven National Lab., Upton, NY (United States)

    1996-12-31

    Collaborative efforts between the International Projects Division (IPD) of the Department of Advanced Technology at Brookhaven National Laboratory, Aquila Technologies Group, Inc. (Aquila), and the General Physics Institute (GPI) in Moscow have developed object recognition technologies to provide real-time intrusion detection capabilities for Aquila`s GEMINI Digital Surveillance System. The research, development and testing for integrating enhanced surveillance capabilities into Aquila`s GEMINI system will receive support from the US Industry Coalition (USIC), an initiative funded by the Initiatives for Proliferation Prevention (IPP), in the coming year. Oversight of the research and development effort is being provided by the IPD staff to ensure that the technical standards of safeguards systems for use by the International Atomic Energy Agency (IAEA) are met. The scientific expertise at GPI is providing breakthroughs in the realm of motion detection for surveillance. Aquila`s contribution to the project focuses on the integration of authenticated digital camera technology for front-end detection. This project illustrates how the application of technology can increase efficiency and reliability of remote monitoring, as well as the timely detection of Safeguards-significant events.

  15. Intrusion detection capabilities of smart video: Collaborative efforts to improve remote monitoring for safeguards surveillance

    International Nuclear Information System (INIS)

    Collaborative efforts between the International Projects Division (IPD) of the Department of Advanced Technology at Brookhaven National Laboratory, Aquila Technologies Group, Inc. (Aquila), and the General Physics Institute (GPI) in Moscow have developed object recognition technologies to provide real-time intrusion detection capabilities for Aquila''s GEMINI Digital Surveillance System. The research, development and testing for integrating enhanced surveillance capabilities into Aquila''s GEMINI system will receive support from the US Industry Coalition (USIC), an initiative funded by the Initiatives for Proliferation Prevention (IPP), in the coming year. Oversight of the research and development effort is being provided by the IPD staff to ensure that the technical standards of safeguards systems for use by the International Atomic Energy Agency (IAEA) are met. The scientific expertise at GPI is providing breakthroughs in the realm of motion detection for surveillance. Aquila''s contribution to the project focuses on the integration of authenticated digital camera technology for front-end detection. This project illustrates how the application of technology can increase efficiency and reliability of remote monitoring, as well as the timely detection of Safeguards-significant events

  16. Remote Pulsed Laser Raman Spectroscopy System for Detecting Qater, Ice, and Hydrous Minerals

    Science.gov (United States)

    Garcia, Christopher S.; Abedin, M. Nuraul; Sharma, Shiv K.; Misra, Anupam K.; Ismail, Syed; Singh, Upendra; Refaat, Tamer F.; Elsayed-Ali, Hani; Sandford, Steve

    2006-01-01

    For exploration of planetary surfaces, detection of water and ice is of great interest in supporting existence of life on other planets. Therefore, a remote Raman spectroscopy system was demonstrated at NASA Langley Research Center in collaboration with University of Hawaii for detecting ice-water and hydrous minerals on planetary surfaces. In this study, a 532 nm pulsed laser is utilized as an excitation source to allow detection in high background radiation conditions. The Raman scattered signal is collected by a 4-inch telescope positioned in front of a spectrograph. The Raman spectrum is analyzed using a spectrograph equipped with a holographic super notch filter to eliminate Rayleigh scattering, and a holographic transmission grating that simultaneously disperses two spectral tracks onto the detector for higher spectral range. To view the spectrum, the spectrograph is coupled to an intensified charge-coupled device (ICCD), which allows detection of very weak Stokes line. The ICCD is operated in gated mode to further suppress effects from background radiation and long-lived fluorescence. The sample is placed at 5.6 m from the telescope, and the laser is mounted on the telescope in a coaxial geometry to achieve maximum performance. The system was calibrated using the spectral lines of a Neon lamp source. To evaluate the system, Raman standard samples such as calcite, naphthalene, acetone, and isopropyl alcohol were analyzed. The Raman evaluation technique was used to analyze water, ice and other hydrous minerals and results from these species are presented.

  17. A generic discriminative part-based model for geospatial object detection in optical remote sensing images

    Science.gov (United States)

    Zhang, Wanceng; Sun, Xian; Wang, Hongqi; Fu, Kun

    2015-01-01

    Detecting geospatial objects with complex structure has been explored for years and it is still a challenging task in high resolution optical remote sensing images (RSI) interpretation. In this paper, we mainly focus on the problem of rotation variance in detecting geospatial objects and propose a generic discriminative part-based model (GDPBM) to build a practical object detection framework. In our model, a geospatial object with arbitrary orientation is divided into several parts and represented via three terms: the appearance features, the spatial deformation features and the rotation deformation features. The appearance features characterize the local patch appearance of the object and parts, and we propose a new kind of rotation invariant feature to represent the appearance using the local intensity gradients. The spatial deformation features capture the geometric deformation of parts by representing the relative displacements among parts. The rotation deformation features define the pose variances of the parts relative to the objects based on their dominant orientations. In generating the two deformation features, we introduce the statistic methods to encode the features in the category level. Concatenating the three terms of the features, a classifier based on the support vector machine is learned to detect geospatial objects. In the experiments, two datasets in optical RSI are used to evaluate the performance of our model and the results demonstrate its robustness and effectiveness.

  18. IMAGE PROCESSING AND REMOTE SENSING – A LULC CHANGE DETECTION USING REMOTELY SENSED DATA FOR COIMBATORE DISTRICT, INDIA

    OpenAIRE

    Dr.K. Thanushkodi, Y. Baby Kalpana, M. Sharrath

    2012-01-01

    Land Use is clearly constrained by environmental factors like soil characteristics, climatic conditions, water sources and vegetation. Changes in Land Use and Land Cover is a dynamic process taking place on the earth surface, and the spatial distribution of the changes that have taken place over a period of time and space is of immense importance in many natural studies. Whether regional or local in scope, remote sensing offers a means of acquiring and presenting land cover data in timely man...

  19. Remote Detection and Analysis of Mass Movements in the Catchment Area of the Xiangxi River/ China

    Science.gov (United States)

    Ye, X.; Xiaofang, G.; Frei, M.; Kaufmann, H.

    2009-04-01

    The overall goal of this project is to develop a better understanding of mechanisms and triggers of mass movements in an area influenced by the rising water level in Three Gorges Dam and to estimate the probability of their occurrence. Investigations are carried out for the Xiangxi river catchment area, a tributary of the Yangtze River discharging into the Three-Gorges-Dam reservoir. In this context, we focus at methodological and conceptual strategies that allow the correlation between recent mass movements with associated soils and lithologies, developed slopes, vegetation coverage and rainfall data. The results provide essential contributions to the estimation of the risk potential and thus, to the safety and future usability of the river banks. To meet the requirements, a synergetic approach of optical imaging and InSAR measurements and advanced remote sensing techniques for data extraction and monitoring are investigated: The differential INSAR method to monitor initial movements along the river banks and optical data for the detection and differentiation of varying soil and rock types as well as for the identification and quantification of vegetation canopies. In addition, geologic structures are deduced from high resolution data and correlated with collected field data. The combination and intersection of remotely derived information with existing thematic data and field knowledge within a GIS system allows for the estimation of the envisaged risk potential.

  20. A combined remote Raman and fluorescence spectrometer system for detecting inorganic and biological materials

    Science.gov (United States)

    Sharma, Shiv K.; Misra, Anupam K.; Lucey, Paul G.

    2006-12-01

    We have developed a combined remote telescopic Raman and laser-induced native fluorescence (LINF) spectrograph with 532 nm pulsed laser excitation and a gated CCD detector. With this system, we have measured time-resolved Raman and LINF spectral measurements at 9 m with 10-ns time resolution. A comparison of Raman spectra of calcite crystal and that of chicken eggshell show that the CaCO 3 in the chicken eggshell is arranged in a calcite structure. The strong LINF band in the spectrum of the calcite crystal has lifetime longer than 1 ?s, whereas the lifetime of LINF bands of the eggshell are in 10's of nano-sec (ns). The time-resolved Raman spectra of tomato and poinsettia (Euphorbia pulcherrimum) green leaves show resonance Raman features of carotenes. The time-resolved remote LINF spectrum of ruby crystals, and LINF spectra of tomato and poinsettia green leaves yield information that the LINF lifetime of ruby lines is much longer (in milliseconds (ms)) as compared with the fluorescence lifetime of the tomato and the poinsettia leaves (in 10s of ns). These results show that it will be possible to discriminate between inorganic and biogenic materials on the basis of LINF lifetimes even with 8 nano-sec laser pulses and gated detection.

  1. Improving model construction of profile HMMs for remote homology detection through structural alignment

    Directory of Open Access Journals (Sweden)

    Zaverucha Gerson

    2007-11-01

    Full Text Available Abstract Background Remote homology detection is a challenging problem in Bioinformatics. Arguably, profile Hidden Markov Models (pHMMs are one of the most successful approaches in addressing this important problem. pHMM packages present a relatively small computational cost, and perform particularly well at recognizing remote homologies. This raises the question of whether structural alignments could impact the performance of pHMMs trained from proteins in the Twilight Zone, as structural alignments are often more accurate than sequence alignments at identifying motifs and functional residues. Next, we assess the impact of using structural alignments in pHMM performance. Results We used the SCOP database to perform our experiments. Structural alignments were obtained using the 3DCOFFEE and MAMMOTH-mult tools; sequence alignments were obtained using CLUSTALW, TCOFFEE, MAFFT and PROBCONS. We performed leave-one-family-out cross-validation over super-families. Performance was evaluated through ROC curves and paired two tailed t-test. Conclusion We observed that pHMMs derived from structural alignments performed significantly better than pHMMs derived from sequence alignment in low-identity regions, mainly below 20%. We believe this is because structural alignment tools are better at focusing on the important patterns that are more often conserved through evolution, resulting in higher quality pHMMs. On the other hand, sensitivity of these tools is still quite low for these low-identity regions. Our results suggest a number of possible directions for improvements in this area.

  2. AIRBORNE, OPTICAL REMOTE SENSING OF METHANE AND ETHANE FOR NATURAL GAS PIPLINE LEAK DETECTION

    Energy Technology Data Exchange (ETDEWEB)

    Jerry Myers

    2004-05-12

    Ophir Corporation was awarded a contract by the U. S. Department of Energy, National Energy Technology Laboratory under the Project Title ''Airborne, Optical Remote Sensing of Methane and Ethane for Natural Gas Pipeline Leak Detection'' on October 14, 2002. The third six-month technical report contains a summary of the progress made towards finalizing the design and assembling the airborne, remote methane and ethane sensor. The vendor has been chosen and is on contract to develop the light source with the appropriate linewidth and spectral shape to best utilize the Ophir gas correlation software. Ophir has expanded upon the target reflectance testing begun in the previous performance period by replacing the experimental receiving optics with the proposed airborne large aperture telescope, which is theoretically capable of capturing many times more signal return. The data gathered from these tests has shown the importance of optimizing the fiber optic receiving fiber to the receiving optic and has helped Ophir to optimize the design of the gas cells and narrowband optical filters. Finally, Ophir will discuss remaining project issues that may impact the success of the project.

  3. Photonuclear Reaction Studies at HI?S: Developing the Science of Remote Detection of Nuclear Materials

    Science.gov (United States)

    Howell, C. R.

    2015-10-01

    Development of gamma-ray beam interrogation technologies for remote detection of special nuclear materials and isotope analysis requires comprehensive databases of nuclear structure information and gamma-ray induced nuclear reaction observables. Relevant nuclear structure details include the energy, spin and parity of excited states that have significant probability for electromagnetic transition from the ground state, i.e, the angular momentum transferred in the reaction is ?l ? 2. This talk will report recent Nuclear Resonance Fluorescence (NRF) measurements to identify and characterize new low-spin states in actinide nuclei at energies from 1 to 4 MeV, which is the energy range most important for remote analysis methods. These measurements are carried out using the nearly mono-energetic linearly polarized gamma-ray beam at the High Intensity Gamma-ray Source (HI?S) at the Triangle Universities Nuclear Laboratory. Also, studies of the (?, n) reaction on a variety of nuclei with linearly polarized beams at HI?S indicate that this reaction might be used to discern between fissile and non-fissile materials. This work will be described. In addition, an overview will be given of a concept for a next generation laser Compton-backing scattering gamma-ray source to be implemented as an upgrade to increase the beam intensity at HI?S by more than an order of magnitude.

  4. EXTENDED PERFORMANCE HANDHELD AND MOBILE SENSORS FOR REMOTE DETECTION OF NATURAL GAS LEAKS

    Energy Technology Data Exchange (ETDEWEB)

    Michael B. Frish; B. David Green; Richard T. Wainner; Francesca Scire-Scappuzzo; Paul Cataldi; Matthew C. Laderer

    2005-05-01

    This report summarizes work performed by Physical Sciences Inc. (PSI) to advance the state-of-the-art of surveying for leaks of natural gas from transmission and distribution pipelines. The principal project goal was to develop means of deploying on an automotive platform an improved version of the handheld laser-based standoff natural gas leak detector previously developed by PSI and known as the Remote Methane Leak Detector or RMLD. A laser beam which interrogates the air for methane is projected from a spinning turret mounted upon a van. As the van travels forward, the laser beam scans an arc to the front and sides of the van so as to survey across streets and to building walls from a moving vehicle. When excess methane is detected within the arc, an alarm is activated. In this project, we built and tested a prototype Mobile RMLD (MRMLD) intended to provide lateral coverage of 10 m and one lateral scan for every meter of forward motion at forward speeds up to 10 m/s. Using advanced detection algorithms developed as part of this project, the early prototype MRMLD, installed on the back of a truck, readily detected simulated gas leaks of 50 liters per hour. As a supplement to the originally planned project, PSI also participated in a DoE demonstration of several gas leak detection systems at the Rocky Mountain Oilfield Testing Center (RMOTC) during September 2004. Using a handheld RMLD upgraded with the advanced detection algorithms developed in this project, from within a moving vehicle we readily detected leaks created along the 7.4 mile route of a virtual gas transmission pipeline.

  5. Optimizing Patient Population for MP-MRI and Fusion Biopsy for Prostate Cancer Detection.

    Science.gov (United States)

    Frye, Thomas P; Pinto, Peter A; George, Arvin K

    2015-07-01

    The diagnosis and treatment of prostate cancer continue to evolve with advances in science and technology. The utilization of multiparametric MRI (mp-MRI) to identify lesions in the prostate has given clinicians the ability to visualize malignancy in the prostate with greater confidence. With this new ability came the advancement of fusion biopsy platforms, which allow for direct targeting of these lesions. As with any new technology in medicine, the proper use of these modalities and how they fit into current clinical practice need to be addressed. This review summarizes the current knowledge on how to best optimize which men undergo mp-MRI and fusion biopsies both in the screening and treatment settings. PMID:26063625

  6. Detection and classification of different liver lesions: Comparison of Gd-EOB-DTPA-enhanced MRI versus multiphasic spiral CT in a clinical single centre investigation

    International Nuclear Information System (INIS)

    Objective: To compare the diagnostic efficacy of Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) vs. multidetector computed tomography (MDCT) for the detection and classification of focal liver lesions, differentiated also for lesion entity and size; a separate analysis of pre- and postcontrast images as well as T2-weighted MRI sequences of focal and exclusively solid lesions was integrated. Methods: Twenty-nine patients with 130 focal liver lesions underwent MDCT (64-detector-row; contrast medium iopromide; native, arterial, portalvenous, venous phase) and MRI (1.5-T; dynamic and tissue-specific phase 20 min after application of Gd-EOB-DTPA). Hepatic lesions were verified against a standard of reference (SOR). CT and MR images were independently analysed by four blinded radiologists on an ordinal 6-point-scale, determining lesion classification and diagnostic confidence. Results: Among 130 lesions, 68 were classified as malignant and 62 as benign by SOR. The detection of malignant and benign lesions differed significantly between combined and postcontrast MRI vs. MDCT; overall detection rate was 91.5% for combined MRI and 80.4% for combined MDCT (p < 0.05). Considering all four readers together, combined MDCT achieved sensitivity of 66.2%, specificity of 79.0%, and diagnostic accuracy of 72.3%; combined MRI reached superior diagnostic efficacy: sensitivity 86.8%, specificity 94.4%, accuracy 90.4% (p < 0.05). Differentiated for lesion size, in particular lesions <20 mm revealed diagnostic benefit by MRI. Postcontrast MRI also achieved higher overall sensitivity, specificity, and accuracy compared to postcontrast MDCT for focal and exclusively solid liver lesions (p < 0.05). Conclusion: Combined and postcontrast Gd-EOB-DTPA-enhanced MRI provided significantly higher overall detection rate and diagnostic accuracy, including low inter-observer variability, compared to MDCT in a single centre study

  7. Morphological MRI criteria improve the detection of lymph node metastases in head and neck squamous cell carcinoma: multivariate logistic regression analysis of MRI features of cervical lymph nodes

    International Nuclear Information System (INIS)

    The aim was to evaluate whether morphological criteria in addition to the size criterion results in better diagnostic performance of MRI for the detection of cervical lymph node metastases in patients with head and neck squamous cell carcinoma (HNSCC). Two radiologists evaluated 44 consecutive patients in which lymph node characteristics were assessed with histopathological correlation as gold standard. Assessed criteria were the short axial diameter and morphological criteria such as border irregularity and homogeneity of signal intensity on T2-weighted and contrast-enhanced T1-weighted images. Multivariate logistic regression analysis was performed: diagnostic odds ratios (DOR) with 95% confidence intervals (95% CI) and areas under the curve (AUCs) of receiver-operating characteristic (ROC) curves were determined. Border irregularity and heterogeneity of signal intensity on T2-weighted images showed significantly increased DORs. AUCs increased from 0.67 (95% CI: 0.61-0.73) using size only to 0.81 (95% CI: 0.75-0.87) using all four criteria for observer 1 and from 0.68 (95% CI: 0.62-0.74) to 0.96 (95% CI: 0.94-0.98) for observer 2 (p < 0.001). This study demonstrated that the morphological criteria border irregularity and heterogeneity of signal intensity on T2-weighted images in addition to size significantly improved the detection of cervical lymph nodes metastases. (orig.)

  8. Hot-Carrier Seebeck Effect: Diffusion and Remote Detection of Hot Carriers in Graphene

    Science.gov (United States)

    Sierra, Juan F.; Neumann, Ingmar; Costache, Marius V.; Valenzuela, Sergio O.

    2015-06-01

    We investigate hot carrier propagation across graphene using an electrical nonlocal injection/detection method. The device consists of a monolayer graphene flake contacted by multiple metal leads. Using two remote leads for electrical heating, we generate a carrier temperature gradient that results in a measurable thermoelectric voltage VNL across the remaining (detector) leads. Due to the nonlocal character of the measurement, VNL is exclusively due to the Seebeck effect. Remarkably, a departure from the ordinary relationship between Joule power P and VNL, VNL ~ P, becomes readily apparent at low temperatures, representing a fingerprint of hot-carrier dominated thermoelectricity. By studying VNL as a function of bias, we directly determine the carrier temperature and the characteristic cooling length for hot-carrier propagation, which are key parameters for a variety of new applications that rely on hot-carrier transport.

  9. Research on ground-based LWIR hyperspectral imaging remote gas detection

    Science.gov (United States)

    Yang, Zhixiong; Yu, Chunchao; Zheng, Weijian; Lei, Zhenggang; Yan, Min; Yuan, Xiaochun; Zhang, Peizhong

    2015-10-01

    The new progress of ground-based long-wave infrared remote sensing is presented, which describes the windowing spatial and temporal modulation Fourier spectroscopy imaging in details. The prototype forms the interference fringes based on the corner-cube of spatial modulation of Michelson interferometer, using cooled long-wave infrared photovoltaic staring FPA (focal plane array) detector. The LWIR hyperspectral imaging is achieved by the process of collection, reorganization, correction, apodization, FFT etc. from data cube. Noise equivalent sensor response (NESR), which is the sensitivity index of CHIPED-1 LWIR hyperspectral imaging prototype, can reach 5.6×10-8W/(cm-1.sr.cm2) at single sampling. Hyperspectral imaging is used in the field of organic gas VOC infrared detection. Relative to wide band infrared imaging, it has some advantages. Such as, it has high sensitivity, the strong anti-interference ability, identify the variety, and so on.

  10. Method of remote powering and detecting multiple UWB passive tags in an RFID system

    Science.gov (United States)

    Dowla, Farid U. (Castro Valley, CA); Nekoogar, Faranak (San Ramon, CA); Benzel, David M. (Livermore, CA); Dallum, Gregory E. (Livermore, CA); Spiridon, Alex (Palo Alto, CA)

    2012-05-29

    A new Radio Frequency Identification (RFID), tracking, powering apparatus/system and method using coded Ultra-wideband (UWB) signaling is introduced. The proposed hardware and techniques disclosed herein utilize a plurality of passive UWB transponders in a field of an RFID-radar system. The radar system itself enables multiple passive tags to be remotely powered (activated) at about the same time frame via predetermined frequency UWB pulsed formats. Once such tags are in an activated state, an UWB radar transmits specific "interrogating codes" to put predetermined tags in an awakened status. Such predetermined tags can then communicate by a unique "response code" so as to be detected by an UWB system using radar methods.

  11. Anomaly Detection Rudiments for the Application of Hyperspectral Sensors in Aerospace Remote Sensing

    International Nuclear Information System (INIS)

    Hyperspectral imaging differs from conventional techniques by exploiting the spectral dimensionality of remote scenes. This additional information promotes discrimination of image elements, especially anomalies that are dissimilar with respect to global features. Algorithms for anomaly detection are designed to overcome the inherent difficulty of analysing hypercubes, which are the higher-dimensional analogues of conventional broadband images. Such algorithms are prolific in their variety and design, which could become an obstacle in choice or application for the neophyte researcher in this field. This paper seeks to consolidate this plethora of algorithms into succinct categories for clarity of rudimentary decision making. A duplicate of article 012048 Snapshot hyperspectral imaging and practical applications was originally published here, in error, as article 012051. The present article replaced the duplicate and was published on 18 August 2009.

  12. Object-based change detection on multiscale fusion for VHR remote sensing images

    Science.gov (United States)

    Zhang, Hansong; Chen, Jianyu; Liu, Xin

    2015-12-01

    This paper presents a novel Object-based context sensitive technique for unsupervised change detection in very high spatial resolution(VHR) remote sensing images. The proposed technique models the scene at different segment levels defining multiscale-level image objects. Multiscale-level image object change features is helpful for improving the discriminability between the changed class and unchanged class. Firstly according to the best classification principle as "homogeneity in class, heterogeneity between class", A set of optimal scales are determined. Then a multiscale level change vector analysis to each pixel of the considered images helps improve the accuracy and the degree of automation, which is implemented on multiscale features fusion. The technique properly analyzes the multiscale-level image objects' context information of the considered spatial position. The adaptive nature of optimal multiscale image objects and their multilevel representation allow one a proper modeling of complex scene in the investigated region. Experimental results confirm the effectiveness of the proposed approach.

  13. Anomaly Detection Rudiments for the Application of Hyperspectral Sensors in Aerospace Remote Sensing

    Science.gov (United States)

    Wong, Gerald

    2009-07-01

    Hyperspectral imaging differs from conventional techniques by exploiting the spectral dimensionality of remote scenes. This additional information promotes discrimination of image elements, especially anomalies that are dissimilar with respect to global features. Algorithms for anomaly detection are designed to overcome the inherent difficulty of analysing hypercubes, which are the higher-dimensional analogues of conventional broadband images. Such algorithms are prolific in their variety and design, which could become an obstacle in choice or application for the neophyte researcher in this field. This paper seeks to consolidate this plethora of algorithms into succinct categories for clarity of rudimentary decision making. A duplicate of article 012048 Snapshot hyperspectral imaging and practical applications was originally published here, in error, as article 012051. The present article replaced the duplicate and was published on 18 August 2009.

  14. Machine learning algorithm accurately detects fMRI signature of vulnerability to major depression.

    Science.gov (United States)

    Sato, João R; Moll, Jorge; Green, Sophie; Deakin, John F W; Thomaz, Carlos E; Zahn, Roland

    2015-08-30

    Standard functional magnetic resonance imaging (fMRI) analyses cannot assess the potential of a neuroimaging signature as a biomarker to predict individual vulnerability to major depression (MD). Here, we use machine learning for the first time to address this question. Using a recently identified neural signature of guilt-selective functional disconnection, the classification algorithm was able to distinguish remitted MD from control participants with 78.3% accuracy. This demonstrates the high potential of our fMRI signature as a biomarker of MD vulnerability. PMID:26187550

  15. Early detection by MRI and conservative therapy of lumbar spondylolysis in the growing period

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Tohru; Namba, Hiromichi; Kasai, Tsutomu; Ohta, Susumu [Yoshida Orthopaedic Hospital, Toyota, Aichi (Japan)

    1996-07-01

    Since 1991 the early cases of spondylolysis in the growing stage have been diagnosed with MRI and treated conservatively by the authors. The final results were obtained in 153 cases (207 arches). The fusion rate of the separated part of these arches was 82% of the total. Treatment consisted mainly of prohibition of exercise and wearing a hard brace. The brace was more effective when worn not only during the day but also throughout the night. On MRI T{sub 1}-weighted images low signal intensity changes of the pars interarticularis proved that bony fusion had been attained with conservative therapy. (author)

  16. CLINICALLY LOCALIZED PROSTATE CANCER: CAPACITIES OF MATRIX COIL MRI TO DETECT MINIMAL EXTRACAPSULAR TUMOR SPREAD

    Directory of Open Access Journals (Sweden)

    E. A. Petrova

    2014-08-01

    Full Text Available Retrospective assessment of preoperative magnetic resonance imaging (MRI data in 37 patients with prostate cancer, who had undergone radical prostatectomy, established the most diagnostically valuable MRI signs of minimal extracapsular spread (ECS: asymmetry of neurovascular fascicles (72 % accuracy, 93 % sensitivity, 77 % specificity, 73 % positive and 94% negative predictive values and iron outline deformity/irregularity (66/80/64/60/82 %, respectively; as well as their higher diagnostic efficiency versus the clinical and laboratory predictors of ECS: total Gleason scores (58/87/55/57/86 %, respectively and serum PSA levels (uninformative, which permits their consideration while choosing a more or less radical prostatectomy modality.

  17. Feasibility study of contaminant detection for food with ULF-NMR/MRI system using HTS-SQUID

    Science.gov (United States)

    Hatsukade, Yoshimi; Tsunaki, Shingo; Yamamoto, Masaaki; Abe, Takayuki; Hatta, Junichi; Tanaka, Saburo

    2013-11-01

    We have developed an ultra-low frequency (ULF) nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) system utilizing an HTS-SQUID for an application of contaminant detection in food and drink. In the system, a permanent magnet of 1.1 T was used to pre-polarize protons in a water sample. We measured NMR signals from water samples with or without various contaminants, such as stainless steel (SUS304), aluminum, and glass balls using the system. In the case that the contaminant was the SUS304 ball, the NMR signal intensity was reduced compared to that from the sample without the contaminant due to the remnant field of the contaminant. One-dimensional (1D) MRIs of the samples were also acquired to detect non-magnetic contaminants. In the 1D MRIs, changes of the MRI spectra were detected, corresponding to positions of the contaminants. These results show that the feasibility of the system to detect various contaminants in foods.

  18. Detection, Identification, Location, and Remote Sensing using SAW RFID Sensor Tags

    Science.gov (United States)

    Barton, Richard J.

    2009-01-01

    In this presentation, we will consider the problem of simultaneous detection, identification, location estimation, and remote sensing for multiple objects. In particular, we will describe the design and testing of a wireless system capable of simultaneously detecting the presence of multiple objects, identifying each object, and acquiring both a low-resolution estimate of location and a high-resolution estimate of temperature for each object based on wireless interrogation of passive surface acoustic wave (SAW) radiofrequency identification (RFID) sensor tags affixed to each object. The system is being studied for application on the lunar surface as well as for terrestrial remote sensing applications such as pre-launch monitoring and testing of spacecraft on the launch pad and monitoring of test facilities. The system utilizes a digitally beam-formed planar receiving antenna array to extend range and provide direction-of-arrival information coupled with an approximate maximum-likelihood signal processing algorithm to provide near-optimal estimation of both range and temperature. The system is capable of forming a large number of beams within the field of view and resolving the information from several tags within each beam. The combination of both spatial and waveform discrimination provides the capability to track and monitor telemetry from a large number of objects appearing simultaneously within the field of view of the receiving array. In the presentation, we will summarize the system design and illustrate several aspects of the operational characteristics and signal structure. We will examine the theoretical performance characteristics of the system and compare the theoretical results with results obtained from experiments in both controlled laboratory environments and in the field.

  19. MOVING OBSTACLE DETECTION AND REMOTE VIDEO MONITORING SYSTEM USING CORTEX-A8

    Directory of Open Access Journals (Sweden)

    V.PADMAJA, KAVITHA MAMINDLA

    2013-11-01

    Full Text Available In this paper the Detection of Moving obstacle and remote video monitoring and extracting the key frames from the captured video system based on high performance SAMSUNG S5PV210 CORTEX-A8 processor core is build and expanding peripheral devices using embedded Linux as the operating system. Today monitoring systems are either webcam based or simple motion detection based. Here we have interfaced both webcam and PIR sensor to the embedded system so that the user can get an immediate alert message and can take necessary steps. This system is based on the kernel of Cortex board with the GSM module being triggered by a Pyroelectric Infrared Sensor (PIR, which senses changes in the external temperature, especially in this case when an invader enters in to remote location and send SMS to the user. At the same time, by using a smart device or a PC, the user can link to the video streaming server constructed on the embedded board via the internet and browse the webpage to monitor the surveillance area, here the UVC driver and V4L programming is used to interface USB camera to the board to capture video information and then board will do two parallel works first one is transmits the processed captured video information using wireless network, which will be collected and monitored at client side using wireless network connection through the wireless device, second one is extracts the key frames from captured video using OpenCV and served on a server, the both provides an advantage to surveillance monitoring system.

  20. Evolution of Coral Rubble Deposits on a Reef Platform as Detected by Remote Sensing

    Directory of Open Access Journals (Sweden)

    Ana Vila-Concejo

    2012-12-01

    Full Text Available An investigation into the evolution of coral rubble deposits on a coral reef platform is assessed using high-resolution remote sensing data and geospatial analysis. Digital change detection analysis techniques are applied to One Tree Reef in the southern Great Barrier Reef by analysing aerial photographs and satellite images captured between 1964 and 2009. Two main types of rubble deposits were identified: (1 rubble flats that are featureless mass accumulations of coral rubble; and, (2 rubble spits that are shore-normal linear features. While both deposits prograde in a lagoon-ward direction, rubble spits move faster (~2 m/yr than rubble flats (~0.5 m/yr. The volume of rubble, the underlying substrate, the energy regime, and storm frequency control the rate of progradation. Rubble flat occurrence is restricted to the high-energy (windward margin of the coral reef platform, while rubble spits are distributed reef wide, both in modal high energy and modal low energy regions of the reef. Rubble spit deposition is considered to be a result of enlarged spur and groove morphology of the forereef, whereby wave energy is focused through the enlarged groove formations causing the preferential deposition of coral rubble in particular zones of the adjacent reef flat. One last control is thought to be the elevation of the reef crest whereby lower areas are more prone to rubble flat development. A vertical and ocean-ward accumulation of rubble is occurring on the windward margin of the reef leading to a build-up and build-out of the reef, governing the expansion of the reef footprint. This study shows for the first time the evolution of a coral reef rubble flat and rubble spits over decadal time scales as detected through remotely sensed images spanning 45 years.

  1. Application of remote sensing in coastal change detection after the tsunami event in Indonesia

    Science.gov (United States)

    Lim, H. S.; MatJafri, M. Z.; Abdullah, K.; Saleh, N. Mohd.; Surbakti, M. S.

    2008-10-01

    Shoreline mapping and shoreline change detection are critical in many coastal zone applications. This study focuses on applying remote sensing technology to identify and assess coastal changes in the Banda Aceh, Indonesia. Major changes to land cover were found along the coastal line. Using remote sensing data to detect coastal line change requires high spatial resolution data. In this study, two high spatial data with 30 meter resolution of Landsat TM images captured before and after the Tsunami event were acquired for this purpose. The two satellite images was overlain and compared with pre-Tsunami imagery and with after Tsunami. The two Landsat TM images also were used to generate land cover classification maps for the 24 December 2004 and 27 March 2005, before and after the Tsunami event respectively. The standard supervised classifier was performed to the satellite images such as the Maximum Likelihood, Minimum Distance-to-mean and Parallelepiped. High overall accuracy (>80%) and Kappa coefficient (>0.80) was achieved by the Maximum Likelihood classifier in this study. Estimation of the damage areas between the two dated was estimated from the different between the two classified land cover maps. Visible damage could be seen in either before and after image pair. The visible damage land areas were determined and draw out using the polygon tool included in the PCI Geomatica image processing software. The final set of polygons containing the major changes in the coastal line. An overview of the coastal line changes using Landsat TM images is also presented in this study. This study provided useful information that helps local decision makers make better plan and land management choices.

  2. AIRBORNE, OPTICAL REMOTE SENSING OF METHANE AND ETHANE FOR NATURAL GAS PIPELINE LEAK DETECTION

    Energy Technology Data Exchange (ETDEWEB)

    Jerry Myers

    2003-05-13

    Ophir Corporation was awarded a contract by the U. S. Department of Energy, National Energy Technology Laboratory under the Project Title ''Airborne, Optical Remote Sensing of Methane and Ethane for Natural Gas Pipeline Leak Detection'' on October 14, 2002. This six-month technical report summarizes the progress for each of the proposed tasks, discusses project concerns, and outlines near-term goals. Ophir has completed a data survey of two major natural gas pipeline companies on the design requirements for an airborne, optical remote sensor. The results of this survey are disclosed in this report. A substantial amount of time was spent on modeling the expected optical signal at the receiver at different absorption wavelengths, and determining the impact of noise sources such as solar background, signal shot noise, and electronic noise on methane and ethane gas detection. Based upon the signal to noise modeling and industry input, Ophir finalized the design requirements for the airborne sensor, and released the critical sensor light source design requirements to qualified vendors. Responses from the vendors indicated that the light source was not commercially available, and will require a research and development effort to produce. Three vendors have responded positively with proposed design solutions. Ophir has decided to conduct short path optical laboratory experiments to verify the existence of methane and absorption at the specified wavelength, prior to proceeding with the light source selection. Techniques to eliminate common mode noise were also evaluated during the laboratory tests. Finally, Ophir has included a summary of the potential concerns for project success and has established future goals.

  3. Sun glint requirement for the remote detection of surface oil films

    Science.gov (United States)

    Sun, Shaojie; Hu, Chuanmin

    2016-01-01

    Natural oil slicks in the western Gulf of Mexico are used to determine the sun glint threshold required for optical remote sensing of oil films. The threshold is determined using the same-day image pairs collected by Moderate Resolution Imaging Spectroradiometer (MODIS) Terra (MODIST), MODIS Aqua (MODISA), and Visible Infrared Imaging Radiometer Suite (VIIRS) (N = 2297 images) over the same oil slick locations where at least one of the sensors captures the oil slicks. For each sensor, statistics of sun glint strengths, represented by the normalized glint reflectance (LGN, sr-1), when oil slicks can and cannot be observed are generated. The LGN threshold for oil film detections is determined to be 10-5-10-6 sr-1 for MODIST and MODISA, and 10-6-10-7 sr-1 for VIIRS. Below these thresholds, no oil films can be detected, while above these thresholds, oil films can always be detected except near the critical-angle zone where oil slicks reverse their contrast against the background water.

  4. River Detection in Remotely Sensed Imagery Using Gabor Filtering and Path Opening

    Directory of Open Access Journals (Sweden)

    Kang Yang

    2015-07-01

    Full Text Available Detecting rivers from remotely sensed imagery is an initial yet important step in space-based river studies. This paper proposes an automatic approach to enhance and detect complete river networks. The main contribution of this work is the characterization of rivers according to their Gaussian-like cross-sections and longitudinal continuity. A Gabor filter was first employed to enhance river cross-sections. Rivers are better discerned from the image background after filtering but they can be easily corrupted owing to significant gray variations along river courses. Path opening, a flexible morphological operator, was then used to lengthen the river channel continuity and suppress noise. Rivers were consistently discerned from the image background after these two-step processes. Finally, a global threshold was automatically determined and applied to create binary river masks. River networks of the Yukon Basin and the Greenland Ice Sheet were successfully detected in two Landsat 8 OLI panchromatic images using the proposed method, yielding a high accuracy (~97.79%, a high true positive rate (~94.33%, and a low false positive rate (~1.76%. Furthermore, experimental tests validated the high capability of the proposed method to preserve river network continuity.

  5. Remote detection of nitroaromatic explosives in soil using distributed sensor particles

    Science.gov (United States)

    Simonson, Robert J.; Hance, Bradley G.; Schmitt, Randal L.; Johnson, Mark S.; Hargis, Philip J., Jr.

    2001-10-01

    Environmental fate and transport studies of explosives in soil indicate that 2,4,6-trinitrotoluene (TNT) and similar products such as dinitrotoluene (DNT) are major contributors to the trace chemical signature emanating from buried landmines. Chemical analysis methods are under development that have great potential to detect mines, or to rapidly classify electromagnetically detected anomalies as mines vs. 'mine-like objects'. However, these chemical methods are currently confined to point sensors. In contrast, we have developed a method that can remotely determine the presence of nitroaromatic explosives in surface soil. This method utilizes a novel distributed granular sensor approach in combination with uv-visible fluorescence LIDAR (Light Detection and Ranging) technology. We have produced prototype sensor particles that combine sample preconcentration, explosives sensing, signal amplification, and optical signal output functions. These particles can be sprayed onto soil areas that are suspected of explosives contamination. By design, the fluorescence emission spectrum of the distributed particles is strongly affected by absorption of nitroaromatic explosives from the surrounding environment. Using ~1mg/cm2 coverage of the sensor particles on natural soil, we have observed significant spectral changes due to TNT concentrations in the ppm range (mg TNT/kg soil) on 2-inch diameter targets at a standoff distance of 0.5 km.

  6. Land cover changed object detection in remote sensing data with medium spatial resolution

    Science.gov (United States)

    Yang, Xiao tong; Liu, Huiping; Gao, Xiaofeng

    2015-06-01

    Land cover change information is crucial to analyse the process and the change patterns of environments and ecological systems. Recent studies have incorporated object-based image analysis for its ability to generate meaningful geographical objects into studies of change detection. In this research, we developed a systematic methodology to realise multi-type land cover changed object detection with medium spatial resolution remote sensing images in Beijing, China. Optimum index factor (OIF) was applied to determine the best change indicators and the chi-square transformation was carried out to determine the change threshold of the 4 classes of changed object. The clustering change vectors in the feature space were proposed to discriminate the change types. According to the accuracy assessment, the overall accuracy of changed/unchanged object detection was approximately 93.9% with an overall kappa of 0.824, and the change type discrimination also achieved an overall accuracy of 81.67%, indicating the effectiveness of the proposed method.

  7. Additional diffusion-weighted imaging in the detection of new, very small hepatocellular carcinoma lesions after interventional therapy compared with conventional 3 T MRI alone

    Energy Technology Data Exchange (ETDEWEB)

    Qu, J.-R [Department of Radiology, Affiliated Cancer Hospital, Zhengzhou University, Zhengzhou (China); Li, H.-L, E-mail: doctor_hnchr@yahoo.com.cn [Department of Radiology, Affiliated Cancer Hospital, Zhengzhou University, Zhengzhou (China); Shao, N.-N; Li, X. [Department of Radiology, Affiliated Cancer Hospital, Zhengzhou University, Zhengzhou (China); Yan, G.-L [Department of Preventive Medicine, School of Basic Medicine, Henan University of Traditional Chinese Medicine, Zhengzhou (China); Zhang, H.-K; Luo, J.-P; Zhang, S.-N; Li, Y.-L; Liu, C.-C [Department of Radiology, Affiliated Cancer Hospital, Zhengzhou University, Zhengzhou (China)

    2012-07-15

    Aim: To evaluate the added value of diffusion-weighted imaging (DWI) combined with conventional magnetic resonance imaging (MRI) in the detection of new, very small hepatocellular carcinoma lesions ({<=}1 cm) in patients with hepatocellular carcinoma following interventional therapy compared to conventional MRI alone. Materials and methods: After interventional therapy, 45 patients with hepatocellular carcinoma underwent conventional MRI and DWI with a b-value of 0 and 700 s/mm{sup 2}. Twenty-one new, small hepatocellular carcinoma lesions were confirmed in 16 patients at follow-up MRI. Two observers independently retrospectively analysed the two imaging sets in random order. The diagnostic performance using each imaging set was evaluated by received operating characteristic curve analysis. Results: Twenty-one new, very small hepatocellular carcinoma lesions found in 16 patients was confirmed as the final result. The area under the receiver operating characteristic curve of the DWI/conventional MRI combination (observer 1, 0.952; observer 2, 0.976) and conventional MRI images alone (observer 1, 0.905; observer 2, 0.905) were statistically significant. The kappa value of the DWI/conventional MRI combination was 0.884, and that of conventional MRI was 0.722. Among the 21 lesions, 100% (21/21) of the lesions were both recognized by two independent reviewers on DWI, while only 76% (16/21) and 71% (15/21) of the lesions were regarded as very small hepatocellular carcinomas on conventional MRI. Conclusion: Due to the higher detection rate of new subcentimetre lesions in hepatocellular carcinoma patients following interventional therapy, DWI could be considered complementary to conventional MRI in the diagnosis of hepatocellular carcinoma.

  8. Cardiac MRI

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Cardiac (Heart) What is Cardiac MRI? What are ... the limitations of Cardiac MRI? What is Cardiac MRI? Magnetic resonance imaging (MRI) is a noninvasive medical ...

  9. Shoulder MRI

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Shoulder Magnetic resonance imaging (MRI) of the shoulder ... limitations of MRI of the shoulder? What is MRI of the shoulder? MRI of the shoulder provides ...

  10. Dynamic gadolinium-enhanced MRI in the detection of spinal arteriovenous malformations

    International Nuclear Information System (INIS)

    Arteriovenous fistulae and malformations (AVFs and AVMs) of the spinal cord are rare, potentially treatable causes of progressive disability. Although a variety of MRI abnormalities has been described, the diagnosis rests on the findings on selective spinal angiography. Collecting T2'-weighted MR images during the passage of a gadolinium bolus gives information about perfusion and blood volume. We carried out dynamic MRI in seven patients with vascular abnormalities (5 dural AVFs, 1 intramedullary AVM, 1 cryptic angioma) and in two patients without an AVM. High resolution T1- and T2-weighted sagittal images of the whole spinal cord were first obtained using a multiarray receiver coil. Sagittal radiofrequency spoilt gradient echo images (GE34/25, flip angle 10 ) were then obtained during bolus injection of gadolinium-DTPA. Abnormalities were seen in all seven patients with AVFs or AVMs. In the patient with an intramedullary AVM and four of the five with dural AVFs transient signal reduction was seen within the perimedullary venous plexus during passage of the bolus. The findings correlated well with those from selective spinal angiography. We conclude that dynamic MRI offers a useful adjunct to angiography and may localise an arteriovenous shunt when conventional MRI fails to do so. In combination with high-resolution imaging of the entire spinal cord the technique may make myelography redundant; it is simple, well tolerated and can be carried out without significant time penalty. (orig.)

  11. Empirical evaluation of bias field correction algorithms for computer-aided detection of prostate cancer on T2w MRI

    Science.gov (United States)

    Viswanath, Satish; Palumbo, Daniel; Chappelow, Jonathan; Patel, Pratik; Bloch, B. Nicholas; Rofsky, Neil; Lenkinski, Robert; Genega, Elizabeth; Madabhushi, Anant

    2011-03-01

    In magnetic resonance imaging (MRI), intensity inhomogeneity refers to an acquisition artifact which introduces a non-linear variation in the signal intensities within the image. Intensity inhomogeneity is known to significantly affect computerized analysis of MRI data (such as automated segmentation or classification procedures), hence requiring the application of bias field correction (BFC) algorithms to account for this artifact. Quantitative evaluation of BFC schemes is typically performed using generalized intensity-based measures (percent coefficient of variation, %CV ) or information-theoretic measures (entropy). While some investigators have previously empirically compared BFC schemes in the context of different domains (using changes in %CV and entropy to quantify improvements), no consensus has emerged as to the best BFC scheme for any given application. The motivation for this work is that the choice of a BFC scheme for a given application should be dictated by application-specific measures rather than ad hoc measures such as entropy and %CV. In this paper, we have attempted to address the problem of determining an optimal BFC algorithm in the context of a computer-aided diagnosis (CAD) scheme for prostate cancer (CaP) detection from T2-weighted (T2w) MRI. One goal of this work is to identify a BFC algorithm that will maximize the CaP classification accuracy (measured in terms of the area under the ROC curve or AUC). A secondary aim of our work is to determine whether measures such as %CV and entropy are correlated with a classifier-based objective measure (AUC). Determining the presence or absence of these correlations is important to understand whether domain independent BFC performance measures such as %CV , entropy should be used to identify the optimal BFC scheme for any given application. In order to answer these questions, we quantitatively compared 3 different popular BFC algorithms on a cohort of 10 clinical 3 Tesla prostate T2w MRI datasets (comprising 39 2D MRI slices): N3 , PABIC, and the method of Cohen et al. Results of BFC via each of the algorithms was evaluated in terms of %CV , entropy, as well as classifier AUC for CaP detection from T2w MRI. The CaP classifier was trained and evaluated on a per-pixel basis using annotations of CaP obtained via registration of T2w MRI and ex vivo whole-mount histology sections. Our results revealed that different BFC schemes resulted in a maximization of different performance measures, that is, the BFC scheme identified by minimization of %CV and entropy was not the one that maximized AUC as well. Moreover, existing BFC evaluation measures (%CV , entropy) did not correlate with AUC (application-based evaluation), but did correlate with each other, suggesting that domain-specific performance measures should be considered in making a decision regarding choice of appropriate BFC scheme. Our results also revealed that N3 provided the best correction of bias field artifacts in prostate MRI data, when the goal was to identify prostate cancer.

  12. Tumorsize dependent detection rate of endorectal MRI of prostate cancer-A histopathologic correlation with whole-mount sections in 70 patients with prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Roethke, Matthias C., E-mail: Matthias.roethke@med.uni-tuebingen.de [Departments of Diagnostic and Interventional Radiology, University of Tuebingen, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany); Lichy, Matthias P.; Jurgschat, Leo [Departments of Diagnostic and Interventional Radiology, University of Tuebingen, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany); Hennenlotter, Joerg [Departments of Urology, University of Tuebingen, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany); Vogel, Ulrich [Departments of Pathology, University of Tuebingen, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany); Schilling, David; Stenzl, Arnulf [Departments of Urology, University of Tuebingen, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany); Claussen, Claus D.; Schlemmer, Heinz-Peter [Departments of Diagnostic and Interventional Radiology, University of Tuebingen, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany)

    2011-08-15

    Purpose: To evaluate the value of T2w endorectal MRI (eMRI) for correct detection of tumor foci within the prostate regarding tumor size. Materials and Methods: 70 patients with histologically proven prostate cancer were examined with T2w eMRI before radical prostatectomy at a 1.5 T scanner. For evaluation of eMRI, two radiologists evaluated each tumor focus within the gland. After radical prostatectomy, the prostates were prepared as whole-mount sections, according to transversal T2w eMRI. For each slice, tumor surroundings were marked and compared with eMRI. Based on whole-mount section, 315 slices were evaluated and 533 tumor lesions were documented. Results: Based on the T2w eMRI, 213 tumor lesions were described. In 137/213, histology could prove these lesions. EMRI was able to visualize 0/56 lesions with a maximum size of <0.3 cm (detection rate 0%), between 0.3 and 0.5 cm 4/116 (3%), between 1 and 0.5 cm 22/169 (13%), between 2 and 1 cm 61/136 (45%) and for >2 cm 50/56 (89%). False positive eMRI findings were: <0.3 cm n = 0, 0.5-0.3 cm n = 12, 0.5-1 cm n = 34, 1-2 cm n = 28 and >2 cm n = 2. Conclusion: T2w eMRI cannot exclude prostate cancer with lesions smaller 10 mm and 0.4 cm{sup 3} respectively. The detection rate for lesions more than 20 mm (1.6 cm{sup 3}) is to be considered as high.

  13. Novel MRI methodology to detect human whole-brain connectivity changes after ingestion of fructose or glucose

    Science.gov (United States)

    Tsao, Sinchai; Wilkins, Bryce; Page, Kathleen A.; Singh, Manbir

    2012-03-01

    A novel MRI protocol has been developed to investigate the differential effects of glucose or fructose consumption on whole-brain functional brain connectivity. A previous study has reported a decrease in the fMRI blood oxygen level dependent (BOLD) signal of the hypothalamus following glucose ingestion, but due to technical limitations, was restricted to a single slice covering the hypothalamus, and thus unable to detect whole-brain connectivity. In another previous study, a protocol was devised to acquire whole-brain fMRI data following food intake, but only after restricting image acquisition to an MR sampling or repetition time (TR) of 20s, making the protocol unsuitable to detect functional connectivity above 0.025Hz. We have successfully implemented a continuous 36-min, 40 contiguous slices, whole-brain BOLD acquisition protocol on a 3T scanner with TR=4.5s to ensure detection of up to 0.1Hz frequencies for whole-brain functional connectivity analysis. Human data were acquired first with ingestion of water only, followed by a glucose or fructose drink within the scanner, without interrupting the scanning. Whole-brain connectivity was analyzed using standard correlation methodology in the 0.01-0.1 Hz range. The correlation coefficient differences between fructose and glucose ingestion among targeted regions were converted to t-scores using the water-only correlation coefficients as a null condition. Results show a dramatic increase in the hypothalamic connectivity to the hippocampus, amygdala, insula, caudate and the nucleus accumben for fructose over glucose. As these regions are known to be key components of the feeding and reward brain circuits, these results suggest a preference for fructose ingestion.

  14. Cest Analysis: Automated Change Detection from Very-High Remote Sensing Images

    Science.gov (United States)

    Ehlers, M.; Klonus, S.; Jarmer, T.; Sofina, N.; Michel, U.; Reinartz, P.; Sirmacek, B.

    2012-08-01

    A fast detection, visualization and assessment of change in areas of crisis or catastrophes are important requirements for coordination and planning of help. Through the availability of new satellites and/or airborne sensors with very high spatial resolutions (e.g., WorldView, GeoEye) new remote sensing data are available for a better detection, delineation and visualization of change. For automated change detection, a large number of algorithms has been proposed and developed. From previous studies, however, it is evident that to-date no single algorithm has the potential for being a reliable change detector for all possible scenarios. This paper introduces the Combined Edge Segment Texture (CEST) analysis, a decision-tree based cooperative suite of algorithms for automated change detection that is especially designed for the generation of new satellites with very high spatial resolution. The method incorporates frequency based filtering, texture analysis, and image segmentation techniques. For the frequency analysis, different band pass filters can be applied to identify the relevant frequency information for change detection. After transforming the multitemporal images via a fast Fourier transform (FFT) and applying the most suitable band pass filter, different methods are available to extract changed structures: differencing and correlation in the frequency domain and correlation and edge detection in the spatial domain. Best results are obtained using edge extraction. For the texture analysis, different 'Haralick' parameters can be calculated (e.g., energy, correlation, contrast, inverse distance moment) with 'energy' so far providing the most accurate results. These algorithms are combined with a prior segmentation of the image data as well as with morphological operations for a final binary change result. A rule-based combination (CEST) of the change algorithms is applied to calculate the probability of change for a particular location. CEST was tested with high-resolution satellite images of the crisis areas of Darfur (Sudan). CEST results are compared with a number of standard algorithms for automated change detection such as image difference, image ratioe, principal component analysis, delta cue technique and post classification change detection. The new combined method shows superior results averaging between 45% and 15% improvement in accuracy.

  15. A suspicious breast lesion detected by dynamic contrast-enhanced MRI and pathologically confirmed as capillary hemangioma: A case report and literature review

    International Nuclear Information System (INIS)

    Breast capillary hemangioma is a type of benign vascular tumor which is rarely seen. Little is known about its presentation on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Here, we describe a case of suspicious breast lesion detected by DCE-MRI and pathologically confirmed as capillary hemangioma. Our case indicates that a small mass with a superficial location, clear boundary, and homogeneous enhancement on DCE-MRI indicates the possible diagnosis of hemangioma, whereby even the lesion presents a washout type curve.

  16. A suspicious breast lesion detected by dynamic contrast-enhanced MRI and pathologically confirmed as capillary hemangioma: A case report and literature review

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Lian He; Li, Qing Chang; Xu, Hong Tao; Wang, Xin; Wang, En Hua [The First Affiliated Hospital and College of Basic Medical Sciences, China Medical University, Shenyang (China); Ma, Shuang [Dept. of Neurology, Sheng Jing Hospital of China Medical University, Shenyang (China)

    2013-12-15

    Breast capillary hemangioma is a type of benign vascular tumor which is rarely seen. Little is known about its presentation on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Here, we describe a case of suspicious breast lesion detected by DCE-MRI and pathologically confirmed as capillary hemangioma. Our case indicates that a small mass with a superficial location, clear boundary, and homogeneous enhancement on DCE-MRI indicates the possible diagnosis of hemangioma, whereby even the lesion presents a washout type curve.

  17. Negative predictive value of multiparametric MRI for prostate cancer detection: Outcome of 5-year follow-up in men with negative findings on initial MRI studies

    Energy Technology Data Exchange (ETDEWEB)

    Itatani, R., E-mail: banguliao@gmail.com [Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1, Honjo, Kumamoto 860-8556 (Japan); Department of Radiology, Kumamoto Chuo Hospital, 1-5-1, Tainoshima, Kumamoto 862-0965 (Japan); Namimoto, T. [Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1, Honjo, Kumamoto 860-8556 (Japan); Atsuji, S.; Katahira, K.; Morishita, S. [Department of Radiology, Kumamoto Chuo Hospital, 1-5-1, Tainoshima, Kumamoto 862-0965 (Japan); Kitani, K.; Hamada, Y. [Department of Urology, Kumamoto Chuo Hospital, 1-5-1, Tainoshima, Kumamoto 862-0965 (Japan); Kitaoka, M. [Department of Pathology, Kumamoto Chuo Hospital, 1-5-1, Tainoshima, Kumamoto 862-0965 (Japan); Nakaura, T. [Department of Diagnostic Radiology, Amakusa Medical Center, Kameba 854-1, Amakusa, Kumamoto 863-0046 (Japan); Yamashita, Y. [Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1, Honjo, Kumamoto 860-8556 (Japan)

    2014-10-15

    Highlights: • We assess the negative predictive value of multiparametric MRI for prostate cancer. • Patients with positive prostate biopsy findings were defined as false-negative. • Patients with negative initial prostate biopsy findings were followed up for 5 years. • The negative predictive value was 89.6% for significant prostate cancer. • MRI is a useful tool to rule out significant prostate cancer before biopsy. - Abstract: Objective: To assess the clinical negative predictive value (NPV) of multiparametric MRI (mp-MRI) for prostate cancer in a 5-year follow-up. Materials and methods: One hundred ninety-three men suspected of harboring prostate cancer with negative MRI findings were included. Patients with positive transrectal ultrasound (TRUS)-guided biopsy findings were defined as false-negative. Patients with negative initial TRUS-guided biopsy findings were followed up and only patients with negative findings by digital rectal examination, MRI, and repeat biopsy and no increase in PSA at 5-year follow-up were defined as “clinically negative”. The clinical NPV of mp-MRI was calculated. For quantitative analysis, mean signal intensity on T2-weighted images and the mean apparent diffusion coefficient value on ADC maps of the initial MRI studies were compared between peripheral-zone (PZ) cancer and the normal PZ based on pathologic maps of patients who had undergone radical prostatectomy. Results: The clinical NPV of mp-MRI was 89.6% for significant prostate cancer. Small cancers, prostatitis, and benign prostatic hypertrophy masking prostate cancer returned false-negative results. Quantitative analysis showed that there was no significant difference between PZ cancer and the normal PZ. Conclusion: The mp-MRI revealed a high clinical NPV and is a useful tool to rule out clinically significant prostate cancer before biopsy.

  18. Negative predictive value of multiparametric MRI for prostate cancer detection: Outcome of 5-year follow-up in men with negative findings on initial MRI studies

    International Nuclear Information System (INIS)

    Highlights: • We assess the negative predictive value of multiparametric MRI for prostate cancer. • Patients with positive prostate biopsy findings were defined as false-negative. • Patients with negative initial prostate biopsy findings were followed up for 5 years. • The negative predictive value was 89.6% for significant prostate cancer. • MRI is a useful tool to rule out significant prostate cancer before biopsy. - Abstract: Objective: To assess the clinical negative predictive value (NPV) of multiparametric MRI (mp-MRI) for prostate cancer in a 5-year follow-up. Materials and methods: One hundred ninety-three men suspected of harboring prostate cancer with negative MRI findings were included. Patients with positive transrectal ultrasound (TRUS)-guided biopsy findings were defined as false-negative. Patients with negative initial TRUS-guided biopsy findings were followed up and only patients with negative findings by digital rectal examination, MRI, and repeat biopsy and no increase in PSA at 5-year follow-up were defined as “clinically negative”. The clinical NPV of mp-MRI was calculated. For quantitative analysis, mean signal intensity on T2-weighted images and the mean apparent diffusion coefficient value on ADC maps of the initial MRI studies were compared between peripheral-zone (PZ) cancer and the normal PZ based on pathologic maps of patients who had undergone radical prostatectomy. Results: The clinical NPV of mp-MRI was 89.6% for significant prostate cancer. Small cancers, prostatitis, and benign prostatic hypertrophy masking prostate cancer returned false-negative results. Quantitative analysis showed that there was no significant difference between PZ cancer and the normal PZ. Conclusion: The mp-MRI revealed a high clinical NPV and is a useful tool to rule out clinically significant prostate cancer before biopsy

  19. Implementation of Hyperspectral Techniques in the Remote Detection of Imported Fire Ants Mounds (Hymenoptera: Formicidae) in Cultivated Turfgrass

    Science.gov (United States)

    Safe, expedient, and cost-effective treatments of imported fire ant (IFA) infestations require technological developments that exploit the use of remotely-sensed contrasting features to detect cryptic mounds in heavily-managed turfgrass. Ground-based implementation of hyperspectral techniques in the...

  20. Detection of coal fire location and change based on multi-temporal thermal remotely sensed data and field measurements

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y.; Jing, L.; Bo, Y.; Shi, P.; Zhang, S. [Beijing Normal University, Beijing (China)

    2007-07-01

    This study focuses on analysis methods for monitoring coal fires, using a combination of multi-temporal thermal infrared data, high spatial resolution remote sensing data and field measurements. This technical note is prepared as a feasibility study for the detection of coal fire dynamics in the Inner Mongolia Autonomous Region in northern China.

  1. Detection of mesoscale zones of atmospheric instabilities using remote sensing and weather forecasting model data

    Science.gov (United States)

    Winnicki, I.; Jasinski, J.; Kroszczynski, K.; Pietrek, S.

    2009-04-01

    The paper presents elements of research conducted in the Faculty of Civil Engineering and Geodesy of the Military University of Technology, Warsaw, Poland, concerning application of mesoscale models and remote sensing data to determining meteorological conditions of aircraft flight directly related with atmospheric instabilities. The quality of meteorological support of aviation depends on prompt and effective forecasting of weather conditions changes. The paper presents a computer module for detecting and monitoring zones of cloud cover, precipitation and turbulence along the aircraft flight route. It consists of programs and scripts for managing, processing and visualizing meteorological and remote sensing databases. The application was developed in Matlab® for Windows®. The module uses products of COAMPS (Coupled Ocean/Atmosphere Mesoscale Prediction System) mesoscale non-hydrostatic model of the atmosphere developed by the US Naval Research Laboratory, satellite images acquisition system from the MSG-2 (Meteosat Second Generation) of the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT) and meteorological radars data acquired from the Institute of Meteorology and Water Management (IMGW), Warsaw, Poland. The satellite images acquisition system and the COAMPS model are run operationally in the Faculty of Civil Engineering and Geodesy. The mesoscale model is run on an IA64 Feniks multiprocessor 64-bit computer cluster. The basic task of the module is to enable a complex analysis of data sets of miscellaneous information structure and to verify COAMPS results using satellite and radar data. The research is conducted using uniform cartographic projection of all elements of the database. Satellite and radar images are transformed into the Lambert Conformal projection of COAMPS. This facilitates simultaneous interpretation and supports decision making process for safe execution of flights. Forecasts are based on horizontal distributions and vertical profiles of meteorological parameters produced by the module. Verification of forecasts includes research of spatial and temporal correlations of structures generated by the model, e.g.: cloudiness, meteorological phenomena (fogs, precipitation, turbulence) and structures identified on current satellite images. The developed module determines meteorological parameters fields for vertical profiles of the atmosphere. Interpolation procedures run at user selected standard (pressure) or height levels of the model enable to determine weather conditions along any route of aircraft. Basic parameters of the procedures determining e.g. flight safety include: cloud base, visibility, cloud cover, turbulence coefficient, icing and precipitation intensity. Determining icing and turbulence characteristics is based on standard and new methods (from other mesoscale models). The research includes also investigating new generation mesoscale models, especially remote sensing data assimilation. This is required by necessity to develop and introduce objective methods of forecasting weather conditions. Current research in the Faculty of Civil Engineering and Geodesy concerns validation of the mesoscale module performance.

  2. Multilayer Markov Random Field models for change detection in optical remote sensing images

    Science.gov (United States)

    Benedek, Csaba; Shadaydeh, Maha; Kato, Zoltan; Szirányi, Tamás; Zerubia, Josiane

    2015-09-01

    In this paper, we give a comparative study on three Multilayer Markov Random Field (MRF) based solutions proposed for change detection in optical remote sensing images, called Multicue MRF, Conditional Mixed Markov model, and Fusion MRF. Our purposes are twofold. On one hand, we highlight the significance of the focused model family and we set them against various state-of-the-art approaches through a thematic analysis and quantitative tests. We discuss the advantages and drawbacks of class comparison vs. direct approaches, usage of training data, various targeted application fields and different ways of Ground Truth generation, meantime informing the Reader in which roles the Multilayer MRFs can be efficiently applied. On the other hand we also emphasize the differences between the three focused models at various levels, considering the model structures, feature extraction, layer interpretation, change concept definition, parameter tuning and performance. We provide qualitative and quantitative comparison results using principally a publicly available change detection database which contains aerial image pairs and Ground Truth change masks. We conclude that the discussed models are competitive against alternative state-of-the-art solutions, if one uses them as pre-processing filters in multitemporal optical image analysis. In addition, they cover together a large range of applications, considering the different usage options of the three approaches.

  3. Remote detection of magmatic water in Bullialdus crater on the Moon

    Science.gov (United States)

    Klima, Rachel L.; Cahill, John; Hagerty, Justin J.; Lawrence, David

    2013-01-01

    Once considered dry compared with Earth, laboratory analyses of igneous components of lunar samples have suggested that the Moon’s interior is not entirely anhydrous. Water and hydroxyl have also been detected from orbit on the lunar surface, but these have been attributed to nonindigenous sources, such as interactions with the solar wind. Magmatic lunar volatiles—evidence for water indigenous to the lunar interior—have not previously been detected remotely. Here we analyse spectroscopic data from the Moon Mineralogy Mapper (M3) and report that the central peak of Bullialdus Crater is significantly enhanced in hydroxyl relative to its surroundings. We suggest that the strong and localized hydroxyl absorption features are inconsistent with a surficial origin. Instead, they are consistent with hydroxyl bound to magmatic minerals that were excavated from depth by the impact that formed Bullialdus Crater. Furthermore, estimates of thorium concentration in the central peak using data from the Lunar Prospector orbiter indicate an enhancement in incompatible elements, in contrast to the compositions of water-bearing lunar samples. We suggest that the hydroxyl-bearing material was excavated from a magmatic source that is distinct from that of samples analysed thus far.

  4. Electromagnetic material changes for remote detection and monitoring: a feasibility study: Progress report

    Energy Technology Data Exchange (ETDEWEB)

    McCloy, John S.; Jordan, David V.; Kelly, James F.; McMakin, Douglas L.; Johnson, Bradley R.; Campbell, Luke W.

    2009-09-01

    A new concept for radiation detection is proposed, allowing a decoupling of the sensing medium and the readout. An electromagnetic material, such as a magnetic ceramic ferrite, is placed near a source to be tracked such as a shipping container. The electromagnetic material changes its properties, in this case its magnetic permeability, as a function of radiation. This change is evident as a change in reflection frequency and magnitude when probed using a microwave/millimeter-wave source. This brief report discusses modeling of radiation interaction of various candidate materials using a radiation detector modeling code Geant4, system design considerations for the remote readout, and some theory of the material interaction physics. The theory of radiation change in doped magnetic insulator ferrites such as yttrium iron garnet (YIG) seems well founded based on literature documentation of the photomagnetic effect. The literature also suggests sensitivity of permittivity to neutrons in some ferroelectrics. Research to date indicates that experimental demonstration of these effects in the context of radiation detection is warranted.

  5. Multisensor remote sensing information fusion for urban area classification and change detection

    Science.gov (United States)

    Palubinskas, Gintautas; Makarau, Aliaksei; Reinartz, Peter

    2011-05-01

    Information extraction from multi-sensor remote sensing imagery is an important and challenging task for many applications such as urban area mapping and change detection. A special acquisition (orthogonal) geometry is of great importance for optical and radar data fusion. This acquisition geometry allows to minimize displacement effects due inaccuracy of Digital Elevation Model (DEM) used for data ortho-rectification and existence of unknown 3D structures in a scene. Final data spatial alignment is performed by recently proposed co-registration method based on a Mutual Information measure. For a combination of features originating from different sources, which are quite often noncommensurable, we propose an information fusion framework called INFOFUSE consisting of three main processing steps: feature fission (feature extraction aiming at complete description of a scene), unsupervised clustering (complexity reduction and feature representation in a common dictionary) and supervised classification realized by Bayesian or Neural networks. An example of urban area classification is presented for the orthogonal acquisition of space borne very high resolution WorldView-2 and TerraSAR-X Spotlight imagery over Munich city, South Germany. Experimental results confirm our approach and show a great potential also for other applications such as change detection.

  6. Rejection of crosstalk and noise by a quasi balanced CFPI for remote ultrasound detection

    International Nuclear Information System (INIS)

    In this paper we show the benefits of a quasi balanced fringe hopping CFPI (confocal Fabry-Perot interferometer) with broadband CMRR (common mode rejection ratio) for remote ultrasound detection. Ultrasonic information in general lies in the phase modulation of laser light which in this case is demodulated by using the CFPI at a certain working point on a fringe. By hopping from the positive to the negative slope on the same fringe the detected ultrasonic signals are inverted. In contrary interference signals like crosstalk from the generation, ghosts, or noise correlated to pulse laser excitation are not influenced and hence get rejected by subtracting the signals from both slopes. Hence, a minimum of two measurements is needed for common mode rejection. The fringe hopping from the positive to the negative slope is done by changing the distance of the CFPI mirrors with a precise piezoelectric-stack and a fast high resolution digital controller. As only one photo-detector with a transimpedance-amplifier is needed a high CMRR can be accomplished which is not affected by the symmetry of the fringe but only by pulse to pulse energy fluctuations of the generation laser. We show that with fringe hopping and averaging the signal to noise ratio increases much faster than with averaging without fringe hopping. This is due to the correlation of the quasi-noise with the generation cycle.

  7. Remote atmospheric breakdown for standoff detection using intense short laser pulse compression

    Science.gov (United States)

    Ting, Antonio C.; Alexeev, Ilya; Gordon, Daniel; Briscoe, Eldridge; Penano, Joseph; Hubbard, Richard F.; Sprangle, Phillip; Rubel, Glenn

    2004-08-01

    A remote atmospheric breakdown (RAB) is a very rich source of ultraviolet (UV) and broadband visible light that could provide the early warning to the presence of CW/BW agents through spectroscopic detection, identification and quantification at extended standoff distances. A low-intensity negatively chirped laser pulse propagating in air compresses in time due to linear group velocity dispersion and focuses transversely due to non-linear effects resulting in rapid laser intensity increase and ionization near the focal region that can be located kilometers away from the laser system. Proof of principle laboratory experiments are being performed at the Naval Research Laboratory on the generation of RAB and the spectroscopic detection of mock BW agents. We have demonstrated pulse compression and focusing up to 105 meters in the laboratory using femtosecond pulses generated by a high power Ti:Sapphire laser. We observed nonlinear modifications to the temporal frequency chirp of the laser pulse and their effects on the laser compression and the positions of the final focus. We have generated third harmonics at 267 nm and white light in air from the compressed pulse. We have observed fluorescence emission from albumin aerosols as they were illuminated by the compressed femtosecond laser pulse.

  8. Comparison of abdominal MRI with diffusion-weighted imaging to {sup 68}Ga-DOTATATE PET/CT in detection of neuroendocrine tumors of the pancreas

    Energy Technology Data Exchange (ETDEWEB)

    Schmid-Tannwald, Christine; Schmid-Tannwald, Christoph M.; Neumann, Ralph; Nikolaou, Konstantin; Schramm, Nicolai; Reiser, Maximilian F.; Rist, Carsten [Ludwig Maximilians University Hospital Munich, Institute for Clinical Radiology, Munich (Germany); Morelli, John N. [Scott and White Hospital Temple, Department of Radiology, Temple, TX (United States); Haug, Alexander R.; Jansen, Nathalie [Ludwig Maximilians University Hospital Munich, Department of Nuclear Medicine, Munich (Germany)

    2013-06-15

    The aim of the study was to evaluate contrast-enhanced MRI, diffusion-weighted MRI (DW MRI), and {sup 68}Ga-DOTATATE positron emission tomography (PET)/CT in the detection of intermediate to well-differentiated neuroendocrine tumors (NET) of the pancreas. Eighteen patients with pathologically proven pancreatic NET who underwent MRI including DW MRI and PET/CT within 6 weeks of each other were included in this retrospective study. Two radiologists evaluated T2-weighted (T2w), T2w + DW MRI, T2w + contrast-enhanced T1-weighted (CE T1w) MR images, and PET/CT for NET detection. The sensitivity and level of diagnostic confidence were compared among modalities using McNemar's test and a Wilcoxon signed rank test. Apparent diffusion coefficients (ADC) of pancreatic NETs and normal pancreatic tissue were compared with Student's t test. Of the NETs, 8/23 (34.8 %) and 9/23 (39.1 %) were detected on T2w images by observers 1 and 2, respectively. Detection rates improved significantly by combining T2w images with DW MRI (observer 1: 14/23 = 61 %; observer 2: 15/23 = 65.2 %; p < 0.05) or CE T1w images (observer 1: 14/23 = 61 %; observer 2: 15/23 = 65.2 %; p < 0.05). Detection rates of pancreatic NET with PET/CT (both observers: 23/23 = 100 %) were statistically significantly higher than with MRI (p < 0.05). The mean ADC value of NET (1.02 {+-} 0.26 x 10{sup -3} mm{sup 2}/s) was statistically significantly lower than that of normal pancreatic tissue (1.48 {+-} 0.39 x 10{sup -3} mm{sup 2}/s). DW MRI is a valuable adjunct to T2w imaging and comparable to CE T1w imaging in pancreatic NET detection, quantitatively differentiating between NET and normal pancreatic tissue with ADC measurements. {sup 68}Ga-DOTATATE PET/CT is more sensitive than MRI in the detection of pancreatic NET. (orig.)

  9. Usefulness of MRI detection of cervical spine and brain injuries in the evaluation of abusive head trauma

    International Nuclear Information System (INIS)

    In the evaluation of children younger than 3 years with intracranial hemorrhage it can be difficult to determine whether the cause of hemorrhage was traumatic, and if so, whether abusive head trauma (AHT) is a possibility. Cervical spine MRI is not a routine part of the nationally recommended imaging workup for children with suspected abusive head trauma. There is increasing evidence that spinal injuries are found at autopsy or MRI in abused children. However the prevalence of cervical spine injuries in children evaluated for abusive head trauma is unknown. We sought to determine both the incidence and the spectrum of cervical spine and brain injuries in children being evaluated for possible abusive head trauma. We also examined the relationship between cervical and brain MRI findings and selected study outcome categories. This study is a 3-year retrospective review of children evaluated for abusive head trauma. Inclusion criteria were: children with head trauma seen at our institution between 2008 and 2010, age younger than 36 months, availability of diagnostic-quality brain and cervical spine MRI, and child abuse team involvement because abusive head trauma was a possibility. A child abuse pediatrician and pediatric radiologists, all with board certification, were involved in data collection, image interpretation and data analysis. Statistical analysis was performed using Stata v12.1. The study included 74 children (43 boys, 31 girls) with a mean age of 164 days (range, 20-679 days). Study outcomes were categorized as: n = 26 children with accidental head trauma, n = 38 with abusive head trauma (n = 18 presumptive AHT, n = 20 suspicious for AHT), and n = 10 with undefined head trauma. We found cervical spine injuries in 27/74 (36%) children. Most cervical spine injuries were ligamentous injuries. One child had intrathecal spinal blood and two had spinal cord edema; all three of these children had ligamentous injury. MRI signs of cervical injury did not show a statistically significant relationship with a study outcome of abusive head trauma or help discriminate between accidental and abusive head trauma. Of the 30 children with supratentorial brain injury, 16 (53%) had a bilateral hypoxic-ischemic pattern. There was a statistically significant relationship between bilateral hypoxic-ischemic brain injury pattern and abusive head trauma (P < 0.05). In addition, the majority (81%) of children with bilateral hypoxic-ischemic brain injuries had cervical injuries. Although detection of cervical spine injuries by MRI does not discriminate between accidental and abusive head trauma, it can help to distinguish a traumatic from non-traumatic intracranial subdural hemorrhage. Cervical MRI should be considered in children with acute intracranial bleeds and otherwise non-contributory history, physical examination and ophthalmological findings. There is a statistically significant relationship between diffuse hypoxic-ischemic brain injury patterns and abusive head trauma. The high incidence of cervical injuries in children with hypoxic-ischemic injuries suggests a causal relationship. Overall, increased utilization of brain and spine MRI in children being evaluated for abusive head trauma can be helpful. (orig.)

  10. Usefulness of MRI detection of cervical spine and brain injuries in the evaluation of abusive head trauma

    Energy Technology Data Exchange (ETDEWEB)

    Kadom, Nadja [Children' s National Medical Center, Department of Diagnostic Imaging and Radiology, Washington, DC (United States); Boston University Medical Center, Boston, MA (United States); Khademian, Zarir; Vezina, Gilbert; Shalaby-Rana, Eglal [Children' s National Medical Center, Department of Diagnostic Imaging and Radiology, Washington, DC (United States); Rice, Amy [Independent Consultant (Biostatistics), Chevy Chase, MD (United States); Hinds, Tanya [Children' s National Medical Center, Child and Adolescent Protection Center, Washington, DC (United States)

    2014-07-15

    In the evaluation of children younger than 3 years with intracranial hemorrhage it can be difficult to determine whether the cause of hemorrhage was traumatic, and if so, whether abusive head trauma (AHT) is a possibility. Cervical spine MRI is not a routine part of the nationally recommended imaging workup for children with suspected abusive head trauma. There is increasing evidence that spinal injuries are found at autopsy or MRI in abused children. However the prevalence of cervical spine injuries in children evaluated for abusive head trauma is unknown. We sought to determine both the incidence and the spectrum of cervical spine and brain injuries in children being evaluated for possible abusive head trauma. We also examined the relationship between cervical and brain MRI findings and selected study outcome categories. This study is a 3-year retrospective review of children evaluated for abusive head trauma. Inclusion criteria were: children with head trauma seen at our institution between 2008 and 2010, age younger than 36 months, availability of diagnostic-quality brain and cervical spine MRI, and child abuse team involvement because abusive head trauma was a possibility. A child abuse pediatrician and pediatric radiologists, all with board certification, were involved in data collection, image interpretation and data analysis. Statistical analysis was performed using Stata v12.1. The study included 74 children (43 boys, 31 girls) with a mean age of 164 days (range, 20-679 days). Study outcomes were categorized as: n = 26 children with accidental head trauma, n = 38 with abusive head trauma (n = 18 presumptive AHT, n = 20 suspicious for AHT), and n = 10 with undefined head trauma. We found cervical spine injuries in 27/74 (36%) children. Most cervical spine injuries were ligamentous injuries. One child had intrathecal spinal blood and two had spinal cord edema; all three of these children had ligamentous injury. MRI signs of cervical injury did not show a statistically significant relationship with a study outcome of abusive head trauma or help discriminate between accidental and abusive head trauma. Of the 30 children with supratentorial brain injury, 16 (53%) had a bilateral hypoxic-ischemic pattern. There was a statistically significant relationship between bilateral hypoxic-ischemic brain injury pattern and abusive head trauma (P < 0.05). In addition, the majority (81%) of children with bilateral hypoxic-ischemic brain injuries had cervical injuries. Although detection of cervical spine injuries by MRI does not discriminate between accidental and abusive head trauma, it can help to distinguish a traumatic from non-traumatic intracranial subdural hemorrhage. Cervical MRI should be considered in children with acute intracranial bleeds and otherwise non-contributory history, physical examination and ophthalmological findings. There is a statistically significant relationship between diffuse hypoxic-ischemic brain injury patterns and abusive head trauma. The high incidence of cervical injuries in children with hypoxic-ischemic injuries suggests a causal relationship. Overall, increased utilization of brain and spine MRI in children being evaluated for abusive head trauma can be helpful. (orig.)

  11. PET/CT and 3-T whole-body MRI in the detection of malignancy in treated oropharyngeal and hypopharyngeal carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Ng, Shu-Hang; Ko, Sheung-Fat [Chang Gung University, Molecular Imaging Center, Taoyuan (China); Linkou Medical Center, Department of Diagnostic Radiology, Chang Gung Memorial Hospital, Taoyuan (China); Chang Gung University, Department of Medical Imaging and Radiological Sciences, Taoyuan (China); Chan, Sheng-Chieh; Yen, Tzu-Chen [Chang Gung University, Molecular Imaging Center, Taoyuan (China); Chang Gung University, Department of Nuclear Medicine, Taoyuan (China); Liao, Chun-Ta; Chang, Kai-Ping [Chang Gung University, Department of Otorhinolaryngology, Head and Neck Surgery, Taoyuan (China); Lin, Chin-Yu; Fan, Kang-Hsing [Chang Gung University, Department of Radiation Oncology, Taoyuan (China); Chang Gung University, Graduate Institute of Clinical Medical Science, Taoyuan (China); Tung-Chieh Chang, Joseph [Chang Gung University, Department of Radiation Oncology, Taoyuan (China); Wang, Hung-Ming [Chang Gung University, Department of Medical Oncology, Chang Gung Memorial Hospital, Taoyuan (China)

    2011-06-15

    We performed a prospective comparison of the diagnostic capability of integrated fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) (PET/CT), 3-T whole-body magnetic resonance imaging (WB-MRI) and their combination in detecting malignancy in treated oropharyngeal or hypopharyngeal squamous cell carcinoma (OHSCC). Seventy-nine OHSCC patients at a high risk of residual disease or suspected to have recurrence after the completion of chemoradiation were included in the study. All patients underwent PET/CT and WB-MRI within 10 days of each other. Histology and follow-up data were used as the reference standard. The McNemar test was used to compare sensitivity and specificity, while the area under the receiver-operating characteristic curve (AUC) was used for comparison of diagnostic capabilities. Twenty-nine patients (36.7%) had residual/recurrent tumours or second primary tumours. Overall, there was a trend towards increased sensitivity and diagnostic capability for PET/CT compared with WB-MRI (72.4 vs 55.2%, p = 0.13; 0.826 vs 0.753, p = 0.24, respectively). The diagnostic capability of combined interpretation of PET/CT and WB-MRI was similar to PET/CT alone (0.827 vs 0.826, p = 0.97) but was significantly higher than WB-MRI alone (0.827 vs 0.753, p = 0.04). PET/CT showed a trend towards higher diagnostic capability than 3-T WB-MRI in detecting residual/recurrent tumours or second primary tumours in OHSCC. The combined use of PET/CT and WB-MRI provided more added value to WB-MRI alone than to PET/CT alone. Additional PET/CT can be useful in patients with questionable MRI findings of malignancy. (orig.)

  12. Labeling of mesenchymal stem cells with different superparamagnetic particles of iron oxide and detectability with MRI at 3T

    International Nuclear Information System (INIS)

    Purpose: In vitro evaluation of labeling efficiency of human mesenchymal stem cells (hMSCs) with different types of superparamagnetic iron oxide nanoparticles as well as detection and quantification by MRI at 3T. Material and methods: hMSCs were incubated for 24 hours with 5 ultrasmall superparamagnetic particles of iron oxide (USPIO) contrast agents (1:30-1:30,000) of different size, coating and core compound: Endorem registered, Resovist registered, citric acid coated magnetite cores of 3 nm (CMF3), 7 nm (CMF7) and 12 nm (CoF; core: cobalt ferrite). Iron uptake, intracellular retention, detection and quantification were evaluated with MRI up to 5 weeks after incubation by cytological analysis (Prussian blue) atomic absorption spectrometry and MR relaxometry measurements. Results: An effective labeling of hMSCs was achieved using Resovist registered, CMF3 and CMF7 with mean iron concentrations of 5.1/1.8, 1.9/1.4 and 1.5/1.0 pg/cell (dilutions 1:30 [933, 2100, 2800 ?g Fe/ml]/1:300 [93, 210, 280 ?g Fe/ml)] compared with 0.58/0.34 and 0.43/0.30 pg/cell (Endorem registered, CoF, dilution 1:30 [400, 4200 ?g Fe/ml]/1:300 [40, 420 ?g Fe/ml] unlabelled control cells: 0.01 pg/cell). Particle uptake correlated with the concentration of USPIO in the incubation medium. Detection of 5 x 104 labelled cells/ml with MRI was possible up to 5 weeks after incubation (Resovist registered, CMF7 and CMF3). MR relaxometry measurements showed a strong correlation between cellular iron load and R2* (1/T2*), r > 0.78. No changes in cell viability or toxic effects were found. Conclusion: Efficiency of labeling hMSCs with USPIOs depends on coating, size and core compound of used particles. Carboxydextran-coated, clinically approved SPIO (Resovist registered, 50 nm) or ultrasmall citrate-coated particles (< 10 mm) result in an improved cellular uptake. In principle, the long intracellular retention of particles offers the possibility of cell tracking and migration monitoring in MRI. (orig.)

  13. Accuracy of abdominal ultrasound and MRI for detection of Crohn disease and ulcerative colitis in children

    Energy Technology Data Exchange (ETDEWEB)

    Ziech, Manon L.W.; Smets, Anne M.J.B.; Lavini, Cristina; Caan, Matthan W.A.; Nederveen, Aart J.; Bipat, Shandra; Stoker, Jaap [Academic Medical Center, Department of Radiology, Amsterdam (Netherlands); Hummel, Thalia Z.; Benninga, Marc A.; Kindermann, Angelika [Emma Children' s Hospital, Academic Medical Center, Department of Pediatric Gastroenterology, Amsterdam (Netherlands); Nievelstein, Rutger A.J. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Roelofs, Joris J.T.H. [Academic Medical Center, Department of Pathology, Amsterdam (Netherlands)

    2014-11-15

    Endoscopy is currently the primary diagnostic technique for inflammatory bowel disease (IBD) in children. To assess the accuracy of US and dynamic contrast-enhanced MRI for diagnosing inflammatory bowel disease and for distinguishing Crohn disease and ulcerative colitis in comparison to a reference standard. Consecutive children with suspected IBD underwent diagnostic workup including ileocolonoscopy and upper gastrointestinal endoscopy as the reference standard, abdominal US, and MR enterography and colonography at 3 T. The protocol included a dynamic contrast-enhanced 3-D sequence. Sensitivity, specificity and kappa values were calculated for one ultrasonographer and two MRI observers. We included 28 children (15 boys) with mean age 14 years (range 10-17 years). The diagnosis was IBD in 23 children (72%), including 12 with Crohn disease, 10 with ulcerative colitis and 1 with indeterminate colitis. For the diagnosis of inflammatory bowel disease the sensitivity was 55% for US and 57% (both observers) for MR entero- and colonography, and the specificity was 100% for US and 100% (observer 1) and 75% (observer 2) for MR entero- and colonography. Combined MRI and US had sensitivity and specificity of 70% and 100% (observer 1) and 74% and 80% (observer 2), respectively. With the addition of a dynamic contrast-enhanced MR sequence, the sensitivity increased to 83% and 87%. US and MRI could only distinguish between Crohn disease and ulcerative colitis when terminal ileum lesions were present. US and MR entero- and colonography have a high accuracy for diagnosing inflammatory bowel disease in children but cannot be used to distinguish Crohn disease and ulcerative colitis. (orig.)

  14. Accuracy of abdominal ultrasound and MRI for detection of Crohn disease and ulcerative colitis in children

    International Nuclear Information System (INIS)

    Endoscopy is currently the primary diagnostic technique for inflammatory bowel disease (IBD) in children. To assess the accuracy of US and dynamic contrast-enhanced MRI for diagnosing inflammatory bowel disease and for distinguishing Crohn disease and ulcerative colitis in comparison to a reference standard. Consecutive children with suspected IBD underwent diagnostic workup including ileocolonoscopy and upper gastrointestinal endoscopy as the reference standard, abdominal US, and MR enterography and colonography at 3 T. The protocol included a dynamic contrast-enhanced 3-D sequence. Sensitivity, specificity and kappa values were calculated for one ultrasonographer and two MRI observers. We included 28 children (15 boys) with mean age 14 years (range 10-17 years). The diagnosis was IBD in 23 children (72%), including 12 with Crohn disease, 10 with ulcerative colitis and 1 with indeterminate colitis. For the diagnosis of inflammatory bowel disease the sensitivity was 55% for US and 57% (both observers) for MR entero- and colonography, and the specificity was 100% for US and 100% (observer 1) and 75% (observer 2) for MR entero- and colonography. Combined MRI and US had sensitivity and specificity of 70% and 100% (observer 1) and 74% and 80% (observer 2), respectively. With the addition of a dynamic contrast-enhanced MR sequence, the sensitivity increased to 83% and 87%. US and MRI could only distinguish between Crohn disease and ulcerative colitis when terminal ileum lesions were present. US and MR entero- and colonography have a high accuracy for diagnosing inflammatory bowel disease in children but cannot be used to distinguish Crohn disease and ulcerative colitis. (orig.)

  15. Limbic changes detected by MRI involved in memory and emotional dysfunctions in Parkinson's disease.

    OpenAIRE

    Ibarretxe Bilbao, Naroa

    2009-01-01

    [eng] According neuropathological research limbic changes occur in Parkinson's disease with and without dementia. Structural MRI have reported atrophy of limbic structures including amygadala and hippocampus, in both demented and non-demented PD patients; and a progression of limbic atrophy over time. In addition, atrophy of paralimbic areas (i.e. paracingulate gyrus) and limbic association cortex (i.e orbitofrontal cortex) has also been reported in PD. Functional studies have also reported l...

  16. Detection of multifocal osteonecrosis in an adolescent with dermatomyositis using whole-body MRI

    International Nuclear Information System (INIS)

    Osteonecrosis is a well-recognized complication of corticosteroid use resulting in significant morbidity, often requiring surgical intervention. Whole-body MRI is a promising method that allows imaging of the whole patient in a reasonable time without the use of ionizing radiation. This technique has the potential for evaluating nonmalignant multifocal skeletal disease like osteonecrosis. This case highlights the value of whole-body MR in an adolescent with dermatomyositis who developed multifocal osteonecrosis. (orig.)

  17. Detection of multifocal osteonecrosis in an adolescent with dermatomyositis using whole-body MRI

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Tania C.M.; Terreri, Maria Teresa A.; Hilario, Maria Odete E. [Federal University of Sao Paulo, Department of Pediatrics, Division of Allergy, Clinical Immunology and Rheumatology, Sao Paulo, SP (Brazil); Lederman, Henrique [Federal University of Sao Paulo, Image Diagnosis Department, Sao Paulo (Brazil); Kaste, Sue C. [St. Jude Children' s Research Hospital, Department of Radiological Sciences, Division of Diagnostic Imaging, Memphis, TN (United States)

    2010-09-15

    Osteonecrosis is a well-recognized complication of corticosteroid use resulting in significant morbidity, often requiring surgical intervention. Whole-body MRI is a promising method that allows imaging of the whole patient in a reasonable time without the use of ionizing radiation. This technique has the potential for evaluating nonmalignant multifocal skeletal disease like osteonecrosis. This case highlights the value of whole-body MR in an adolescent with dermatomyositis who developed multifocal osteonecrosis. (orig.)

  18. MRI of prostate cancer using three different coil systems: image quality, tumor detection, and staging

    International Nuclear Information System (INIS)

    Purpose: To compare three MRI coil systems in terms of image quality, delineation of prostate cancer, and tumor staging. Materials and Methods: 49 patients with prostate cancer underwent MRI at 1.5 Tesla using a combination of an endorectal coil with a phased-array body coil (combination coil) prior to radical prostatectomy. Images were reconstructed from the data sets acquired with the endorectal coil alone and from those acquired with the combined coil. In addition, 19 patients of the study patients were examined with the body phased-array coil alone without the endorectal coil. The prostate was imaged at a slice thickness of 3 mm using axial and coronal T2-weighted sequences and an axial T1-weighted sequence. Preoperative analysis of all images acquired was done to determine the accuracy of MRI in local staging of prostate cancer. An additional retrospective analysis served to compare the different coil systems in terms of overall image quality, delineation and localization of the tumor, and criteria for local staging of prostate cancer. Results: Preoperative analysis showed MRI to have an accuracy of 59% in local tumor staging. Retrospective coil-by-coil analysis demonstrated image quality and tumor delineation to be best for the combination coil and the endorectal coil. Regarding the staging criteria for transcapsular tumor extension and infiltration of adjacent organs, a significant advantage of the combination coil compared to the endorectal coil was identified only for the criterion of smooth bulging. In addition, the endorectal coil and the combination coil were found to be superior to the body phased-array coil in assessing 15 of 17 criteria for local tumor staging but the differences were not significant. Conclusion: In view of the achieved superior image quality, the combination coil or the endorectal coil is the preferred method for staging prostate cancer. (orig.)

  19. Diagnostic accuracy of stress myocardial perfusion MRI and late gadolinium-enhanced MRI for detecting flow-limiting coronary artery disease: a multicenter study

    Energy Technology Data Exchange (ETDEWEB)

    Kitagawa, Kakuya [Mie University Hospital, Department of Radiology, Tsu, Mie (Japan); Johns Hopkins University, Division of Cardiology, Department of Medicine, Baltimore, MD (United States); Sakuma, Hajime; Nagata, Motonori; Takeda, Kan [Mie University Hospital, Department of Radiology, Tsu, Mie (Japan); Okuda, Shigeo; Tanimoto, Akihiro; Kuribayashi, Sachio [Keio University School of Medicine, Department of Radiology, Tokyo (Japan); Hirano, Masaharu [Tokyo Medical University, Department of Internal Medicine, Tokyo (Japan); Matsusako, Masaki [St. Luke' s International Hospital, Department of Radiology, Tokyo (Japan); Lima, Joao A.C. [Johns Hopkins University, Division of Cardiology, Department of Medicine, Baltimore, MD (United States)

    2008-12-15

    The aim of this study was to determine the diagnostic performance of stress and rest perfusion magnetic resonance imaging (MRI) and late gadolinium-enhanced (LGE) MRI for identifying patients with obstructive coronary artery disease (CAD). A total of 50 patients with suspected CAD underwent stress-rest perfusion MRI, followed by LGE MRI with a 1.5-T system. Stress-rest perfusion MRI resulted in an area under the receiver-operating characteristic curve (AUC) of 0.92 for observer 1 and 0.84 for observer 2 with sensitivity and specificity of 89% (32/36) and 79% (11/14) by observer 1, 83% (30/36) and 71% (10/14) by observer 2, respectively, showing a moderate interobserver agreement (Cohen's {kappa} = 0.49). While combination of stress-rest perfusion and LGE MRI did not result in improved accuracy for the prediction of flow-limiting obstructive CAD (AUC 0.81 for observer 1 and 0.80 for observer 2), the sensitivity was increased to 92% in both observers with a substantial interobserver agreement ({kappa} = 0.70). Stress-rest myocardial perfusion MRI is an accurate diagnostic test for identifying patients with obstructive CAD. (orig.)

  20. ROLE OF MULTIPARAMETRIC MRI IN THE DETECTION AND LOCALIZATION OF EARLY-STAGE PROSTATE CANCER

    Directory of Open Access Journals (Sweden)

    G. I. Akhverdieva

    2014-07-01

    Full Text Available The efficiency of prostate cancer (PC diagnosis using multipatametric magnetic resonance imaging (MRI was evaluated. Unlike most of investigations of the similar problem, this trial provides an objective assessment applying the method of statistical analysis - binary logistic regression. It used data on 166 patients, including primary patients (with suspected PC, as well as patients with the established diagnosis of PC, those with a history of negative biopsy, and those with suspected recurrent PC. Some patients underwent target biopsy, the results of which were then employed for statistical processing. The data of the analysis showed that the sensitivity, specificity, and total accuracy of the method using the created model of binary logistic regression at the separation value of 0.625 were 75.0, 85.2, and 79.7%, respectively. The efficiency of diffusion-weighted images (DWI with varying weighing degree by water molecule diffusion (b factor on MRI systems with different magnetic field strength (1.5 and 3 Tesla was also evaluated. There were no statistically significant differences in normalized absolute signal intensity as to the contralateral gland portion in DWI with b factors of 1000 and 2000 between the MRI systems with a magnetic field strength of 1.5 and 3.0 Tesla.

  1. Checkmark: a sign for the detection of iliopsoas pathology on MRI of the hip

    Energy Technology Data Exchange (ETDEWEB)

    Eshed, Iris; Inbar, Yael; Hertz, Marjorie; Apter, Sara (Dept. of Diagnostic Imaging, Sheba Medical Center, Tel Hashomer, Sackler School of Medicine, Tel Aviv Univ., Tel Aviv (Israel)), e-mail: iris.eshed@sheba.health.gov.il

    2010-06-15

    Background: The iliopsoas compartment can be involved in many different disease processes with a wide variety of symptoms that may simulate avascular necrosis (AVN) of the femoral head. The psoas muscle merges with the iliacus to form a checkmark (v) shape in the coronal MRI plane, with normal muscle intensities, on both sides of the spine. Purpose: To evaluate whether abnormality of this checkmark shape (obliteration or abnormal intensity), the checkmark sign, can be used as a simple indicator of iliopsoas pathologies on MR examinations performed for suspected AVN of the hip. Material and Methods: A total of 75 hip MRI examinations performed during 2007 for suspected AVN (male:female ratio, 44:31; average age, 41 years) were retrospectively assessed. The iliopsoas compartment was assessed on the coronal T1 and T2 fat saturated sequences for the presence of the checkmark sign by a consensus of two readers. Results: Twenty-six patients had signs of AVN and 49 patients had either other hip findings or normal hips. A normal checkmark shape was observed in all but two examinations. Obliteration of the checkmark shape, a positive checkmark sign, in those two was due to psoas compartment pathology (infection and hematoma of the iliopsoas compartment). Conclusion: A positive checkmark sign (abnormal shape or intensity) can serve as a clue for unsuspected iliopsoas pathology when evaluating MRI of the hip in patients with suspected AVN

  2. Image processing for the detection of functional areas affected by stroke in the brain MRI

    Directory of Open Access Journals (Sweden)

    Yazid Cherfa

    2010-06-01

    Full Text Available The aim of this work is to design a system applied to magnetic resonance brain images (MRI that are multi-ponderable (T2, Diffusion, Flair, taken at different times according to changes in the pathology, from patients suffering from stroke. The system is designed so as to take advantage of several complementary approaches. We opted for a 2D cooperative segmentation region/edge cuts, preceded by an adequate preprocessing phase suitable for MRI data. These operations aim at improving image quality and reduce the large amount of information contained in a cerebral image. The following phase consists of a stroke geometric characterization, a 3D reconstruction of the image, a registration with a reference image, including functional areas in order to recognize the functional areas of the brain affected by the injury. The result of the mapping of the brain and brain segmented reference Broadmann, followed by determining the functional areas affected by stroke, has been validated by clinical examination of the patient.We used MRI images of subjects with stroke who have been appraised by clinicians Tools such as mathematical morphology, anisotropic diffusion, image segmentation, cooperative techniques, and image registration were used for this task. Our method can be used in the aid to diagnosis or surgery, or the temporal monitoring of the pathology according to a therapy. Acknowledgment: We would like to thank the neurology department of the hospital in Grenoble for providing the images, and Catherine Garbay UJF of Grenoble for her help

  3. Can we detect water stressed areas in forest thanks thermal infrared remote sensing?

    Science.gov (United States)

    Nourtier, Marie; Chanzy, André; Bes, Bernard; Mariotte, Nicolas

    2010-05-01

    In Mediterranean and mountainous areas, an increase of mortality in forest is observed after important drought events. In the context of climate changes, a study of the impact of drought stress on forest is necessary. In order to detect water stress over the whole forest at different periods of the year, we propose the use of a spatialisable indicator, easily measurable: crown surface temperature. As previous works were not conclusive concerning the potentiality of this indicator in forest (Duchemin, 1998a, 1998b, Pierce et al., 1990), we set up an experimentation to study the surface temperature evolution linked to the transpiration at tree scale, during the spring and summer periods on silver fir (Abies alba) forest of Mont Ventoux (south of France). At the same time, several thermal infrared images of the mountainside were acquired corresponding to different levels of transpiration. The signal of surface temperature is studying via the evolution of the difference between measured surface temperature and calculated surface temperature for a tree at maximum transpiration rate. At tree scale, there is a difference of 4 °C of amplitude in the signal of surface temperature between maximum and zero transpiration conditions. The difficulty resides in taking into account the influence of climatic conditions, source of variability in the signal uncorrelated with transpiration evolution. Indices of surface temperature, built to include this influence of climatic conditions, permit to reduce this variability. Another source of variability lies in the percentage of branches present in the area of measurement. Indeed branches have a thermal dynamic differing from the needles one and, considering comparison between trees, the percentage of branches varies. At the mountainside scale, contrasted areas in terms of surface temperature indices are observable. By comparing different dates, corresponding to different levels of drought, it is possible to locate areas with precocious water stress signal. The amplitude of the signal, between wet and dry conditions, is at an average of 3 °C. Thus, by analysing the temporal evolution of this signal, thermal infrared is an interesting tool to detect water stress and identify different levels of stress between forest areas. Duchemin B., D. Guyon, J.P. Lagouarde, 1998. Potential and limits of NOAA-AVHRR temporal composite data forr phenology and water stress monitoring of temperate forest ecosystems. International Journal of remote sensing, volume: 20, 5, p 23. Duchemin B., Lagouarde J.P., 1998. Apport des capteurs satellitaires à large champ pour l'estimation de variables de fonctionnement des écosystèmes forestiers tempérés. Thesis. p120. Pierce L. L., Running S.W., Riggs G.A., 1990. Remote detection of canopy water stress in coniferous forests unsing the NS001 Thematic Mapper Simulator and the Thermal Infrared Multispectral Scanner. Photogrammetric engineering and remote sensing, volume: 56, 1, p 8.

  4. Influence of imaging and histological factors on prostate cancer detection and localisation on multiparametric MRI: a prospective study

    Energy Technology Data Exchange (ETDEWEB)

    Bratan, Flavie [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Urinary and Vascular Radiology, Lyon (France); Inserm, U1032, LabTau, Lyon (France); Niaf, Emilie [Inserm, U1032, LabTau, Lyon (France); CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Villeurbanne (France); Melodelima, Christelle [Universite Joseph Fourier, Laboratoire d' Ecologie Alpine, CNRS UMR 5553, BP 53, Grenoble (France); Chesnais, Anne Laure; Mege-Lechevallier, Florence [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Pathology, Lyon (France); Souchon, Remi [Inserm, U1032, LabTau, Lyon (France); Colombel, Marc [Universite de Lyon, Lyon (France); Universite Lyon 1, Faculte de Medecine Lyon Est, Lyon (France); Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Urology, Lyon (France); Rouviere, Olivier [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Urinary and Vascular Radiology, Lyon (France); Inserm, U1032, LabTau, Lyon (France); Universite de Lyon, Lyon (France); Universite Lyon 1, Faculte de Medecine Lyon Est, Lyon (France); Hopital E. Herriot, Service de Radiologie Urinaire et Vasculaire, Pavillon P, Lyon Cedex 03 (France)

    2013-07-15

    To assess factors influencing prostate cancer detection on multiparametric (T2-weighted, diffusion-weighted, and dynamic contrast-enhanced) MRI. One hundred and seventy-five patients who underwent radical prostatectomy were included. Pre-operative MRI performed at 1.5 T (n = 71) or 3 T (n = 104), with (n = 58) or without (n = 117) an endorectal coil were independently interpreted by two radiologists. A five-point subjective suspicion score (SSS) was assigned to all focal abnormalities (FAs). MR findings were then compared with whole-mount sections. Readers identified 192-214/362 cancers, with 130-155 false positives. Detection rates for tumours of <0.5 cc (cm{sup 3}), 0.5-2 cc and >2 cc were 33-45/155 (21-29 %), 15-19/35 (43-54 %) and 8-9/12 (67-75 %) for Gleason {<=}6, 17/27 (63 %), 42-45/51 (82-88 %) and 34/35 (97 %) for Gleason 7 and 4/5 (80 %), 13/14 (93 %) and 28/28 (100 %) for Gleason {>=}8 cancers respectively. At multivariate analysis, detection rates were influenced by tumour Gleason score, histological volume, histological architecture and location (P < 0.0001), but neither by field strength nor coils used for imaging. The SSS was a significant predictor of both malignancy of FAs (P < 0.005) and aggressiveness of tumours (P < 0.00001). Detection rates were significantly influenced by tumour characteristics, but neither by field strength nor coils used for imaging. The SSS significantly stratified the risk of malignancy of FAs and aggressiveness of detected tumours. (orig.)

  5. Influence of imaging and histological factors on prostate cancer detection and localisation on multiparametric MRI: a prospective study

    International Nuclear Information System (INIS)

    To assess factors influencing prostate cancer detection on multiparametric (T2-weighted, diffusion-weighted, and dynamic contrast-enhanced) MRI. One hundred and seventy-five patients who underwent radical prostatectomy were included. Pre-operative MRI performed at 1.5 T (n = 71) or 3 T (n = 104), with (n = 58) or without (n = 117) an endorectal coil were independently interpreted by two radiologists. A five-point subjective suspicion score (SSS) was assigned to all focal abnormalities (FAs). MR findings were then compared with whole-mount sections. Readers identified 192-214/362 cancers, with 130-155 false positives. Detection rates for tumours of 3), 0.5-2 cc and >2 cc were 33-45/155 (21-29 %), 15-19/35 (43-54 %) and 8-9/12 (67-75 %) for Gleason ?6, 17/27 (63 %), 42-45/51 (82-88 %) and 34/35 (97 %) for Gleason 7 and 4/5 (80 %), 13/14 (93 %) and 28/28 (100 %) for Gleason ?8 cancers respectively. At multivariate analysis, detection rates were influenced by tumour Gleason score, histological volume, histological architecture and location (P < 0.0001), but neither by field strength nor coils used for imaging. The SSS was a significant predictor of both malignancy of FAs (P < 0.005) and aggressiveness of tumours (P < 0.00001). Detection rates were significantly influenced by tumour characteristics, but neither by field strength nor coils used for imaging. The SSS significantly stratified the risk of malignancy of FAs and aggressiveness of detected tumours. (orig.)

  6. Detection of Shoreline and Land Cover Changes around Rosetta Promontory, Egypt, Based on Remote Sensing Analysis

    Directory of Open Access Journals (Sweden)

    Ali Masria

    2015-03-01

    Full Text Available Rosetta Promontory, Egypt has been suffering from a continuous erosion problem. The dramatic retreatment was observed during the last century. It is basically due to the construction of Aswan High Dam in 1964, which reduced the flow and sediment discharges. In this paper, four Landsat images (two Thematic Mapper and two Enhanced Thematic Mapper covering the period from 1984 to 2014 were used. These Landsat images were radio-metrically and geometrically corrected, and then, multi-temporal post-classification analysis was performed to detect land cover changes, extracting shoreline positions to estimate shoreline change rates of the Nile delta coast around Rosetta Promontory. This method provides a viable means for examining long-term shoreline changes. Four categories, including seawater, developed (agriculture and urban, sabkhas (salt-flat, and undeveloped areas, were selected to evaluate their temporal changes by comparing the four selected images. Supervised classification technique was used with support vector machine algorithm to detect temporal changes. The overall accuracy assessment of this method ranged from 97% to 100%. In addition, the shoreline was extracted by applying two different techniques. The first method is based on a histogram threshold of Band 5, and the other uses the combination of histogram threshold of Band 5 and two band ratios (Band 2/Band 4 and Band 2/Band 5. For land cover change detection from 1984 to 2014, it was found that the developed area that increased by 9% although the land in the study area has been contracted by 1.6% due to coastal erosion. The shoreline retreat rate has decreased more than 70% from 1984 to 2014. Nevertheless, it still suffers from significant erosion with a maximum rate of 37 m/year. In comparison to ground survey and different remote sensing techniques, the established trend of shoreline change extracted using histogram threshold was found to be closely consistent with these studies rather than combining band ratio with histogram threshold.

  7. GPU implementation of target and anomaly detection algorithms for remotely sensed hyperspectral image analysis

    Science.gov (United States)

    Paz, Abel; Plaza, Antonio

    2010-08-01

    Automatic target and anomaly detection are considered very important tasks for hyperspectral data exploitation. These techniques are now routinely applied in many application domains, including defence and intelligence, public safety, precision agriculture, geology, or forestry. Many of these applications require timely responses for swift decisions which depend upon high computing performance of algorithm analysis. However, with the recent explosion in the amount and dimensionality of hyperspectral imagery, this problem calls for the incorporation of parallel computing techniques. In the past, clusters of computers have offered an attractive solution for fast anomaly and target detection in hyperspectral data sets already transmitted to Earth. However, these systems are expensive and difficult to adapt to on-board data processing scenarios, in which low-weight and low-power integrated components are essential to reduce mission payload and obtain analysis results in (near) real-time, i.e., at the same time as the data is collected by the sensor. An exciting new development in the field of commodity computing is the emergence of commodity graphics processing units (GPUs), which can now bridge the gap towards on-board processing of remotely sensed hyperspectral data. In this paper, we describe several new GPU-based implementations of target and anomaly detection algorithms for hyperspectral data exploitation. The parallel algorithms are implemented on latest-generation Tesla C1060 GPU architectures, and quantitatively evaluated using hyperspectral data collected by NASA's AVIRIS system over the World Trade Center (WTC) in New York, five days after the terrorist attacks that collapsed the two main towers in the WTC complex.

  8. Land-cover change detection for the tropics using remote sensing and geographic information systems

    Science.gov (United States)

    Read, Jane M.

    1999-12-01

    Changing land-cover in the tropics is a central issue in global change research. This dissertation used Landsat-TM data to examine processes of land-use and land-cover changes for a lowland tropical site in Sarapiqui, Costa Rica. Performances of selected image-processing methods to detect and identify land-cover changes were evaluated. A land-cover time-series from 1960 to 1996 for the site was generated using maps derived from aerial photographs and Landsat-TM classifications. Changes in land-cover from 1986 to 1996 were evaluated using standard landscape indices, and interpreted in terms of their historical context. Dominant changes in the site during this decade included the breakup of extensive cattle ranches for large-scale plantation enterprises and small-scale farming. Colonization processes, improvements in access, and changes in export markets were identified as the major driving forces of change. Evaluation of change-detection methods revealed that postclassification comparison performed significantly better than image differencing algorithms. Image differencing using mid- infrared bonds performed the best of the differencing algorithms tested. Selection of a suitable change-detection method can be aided through examination of the individual bond statistics for the specific area and problem in question. The univariate bond differencing technique has potential for identification of 'hot spots' of change using Landsat-TM data. Spatial pattern-recognition techniques to characterize complexity of Landsat-TM data were evaluated. Fractal dimension calculated using the triangular prism surface area method, and Moran's I index of spatial autocorrelation, clearly distinguished different land-cover types. Shannon's diversity index and the contagion metric were not found to be useful in characterizing the images. The use of fractal dimension, in conjunction with standard non-spatial descriptive band statistics, are seen as having great potential in characterizing unclassified remotely sensed data based on differences in land-cover types. These statistics could be further developed for rapid environmental monitoring.

  9. IMAGING IN PEDIATRIC EPILEPSY: SPECTRUM OF ABNORMAL ITIES DETECTED ON MRI

    Directory of Open Access Journals (Sweden)

    Rachna

    2013-05-01

    Full Text Available ABSTRACT: OBJECTIVE: To evaluate role of radio-imaging, with emphasis o n MRI in comparison to other modalities, in patients of paediatric age gro up presenting with epilepsy and correlate it with clinical findings in Bundelkhand region. METHODS: Prospective data was obtained from evaluation of patients presenting with epilepsy in paediatric OPD and IPD, between 2010 and 2012. A total of 271 patients presenting with epilepsy (> 2 episodes of seizures were included. CBC, Chest X-ray and CSF analysis were also performed for clinical evalu ation as per need. Neurosonogram was done in 41 children below age of 1year (15.1%, Head CT was ob tained in 167 (61.7%, MRI in all cases. EEG was done in all cases, except in 5 cases of trauma. Epilepsy provoked by causes such as fever, electrolyte imbalance and dehydration were excluded . RESULTS: We observed that generalized seizures were more common presentation, followed by partial seizures, mostly complex. Majority had more than 2 episodes of seizures at the time of presentation. MRI revealed positive findings in 191 cases (70.4% and CT in 64 cases (38.3% of 167 done. MRI had positive findings in 35 cases (34.0% of 103 with normal CT scan. Most common cau se of epilepsy in this region was found to be CNS tuberculosis (Tuberculomas, 15.7% & TBM, 14.6% , followed by Neurocysticercosis (11.0%, Encephalitis (7.9%, Demyelination (6.8%, Gliosis with or without Encephalomalacia (6.8%, Periventricular leukomalacia (5.2%, Infarct (4.7% & porencephaly (3.7%. Rare causes observed were leukodystrophy (7cases, intra-axial bleed (4 case and extra-axial bleed (5case, heterotopias (4 case, abscess (2case and Phakomatosis (Tuberou s Sclerosis, 1 case. CONCLUSION: Since most of the seizures begin in paediatric age-group, whic h is crucial time for physical, psychosocial & mental growth, it is essential to evaluate the dive rse varieties of aetiologies and manage patient accordingly. MRI thus proves to be the best for alm ost all pathologies, causing epilepsy, except trauma.

  10. Whole-body MRI for the detection of bone marrow involvement in lymphoma: prospective study in 116 patients and comparison with FDG-PET

    International Nuclear Information System (INIS)

    To assess and compare the value of whole-body MRI with FDG-PET for detecting bone marrow involvement in lymphoma. A total of 116 patients with newly diagnosed lymphoma prospectively underwent whole-body MRI and blind bone marrow biopsy (BMB) of the posterior iliac crest. Of 116 patients, 80 also underwent FDG-PET. Patient-based sensitivities of whole-body MRI for detecting bone marrow involvement were calculated using BMB as reference standard and compared with FDG-PET in aggressive and indolent lymphomas separately. Sensitivity of whole-body MRI in all lymphomas was 45.5 % [95 % confidence interval (CI): 29.8-62.0 %]. Sensitivity of whole-body MRI in aggressive lymphoma [88.9 % (95 % CI: 54.3-100 %)] was significantly higher (P = 0.0029) than that in indolent lymphoma [23.5 % (95 % CI: 9.1-47.8 %)]. Sensitivity of FDG-PET in aggressive lymphoma [83.3 % (95 % CI: 41.8-98.9 %)] was also significantly higher (P = 0.026) than that in indolent lymphoma [12.5 % (95 % CI: 0-49.2 %)]. There were no significant differences in sensitivity between whole-body MRI and FDG-PET (P = 1.00) Sensitivity of whole-body MRI for detecting lymphomatous bone marrow involvement is too low to (partially) replace BMB. Sensitivity of whole-body MRI is significantly higher in aggressive lymphoma than in indolent lymphoma and is equal to FDG-PET in both entities. (orig.)

  11. Remote sensing analysis for fault-zones detection in the Central Andean Plateau (Catamarca, Argentina)

    Science.gov (United States)

    Traforti, Anna; Massironi, Matteo; Zampieri, Dario; Carli, Cristian

    2015-04-01

    Remote sensing techniques have been extensively used to detect the structural framework of investigated areas, which includes lineaments, fault zones and fracture patterns. The identification of these features is fundamental in exploration geology, as it allows the definition of suitable sites for the exploitation of different resources (e.g. ore mineral, hydrocarbon, geothermal energy and groundwater). Remote sensing techniques, typically adopted in fault identification, have been applied to assess the geological and structural framework of the Laguna Blanca area (26°35'S-66°49'W). This area represents a sector of the south-central Andes localized in the Argentina region of Catamarca, along the south-eastern margin of the Puna plateau. The study area is characterized by a Precambrian low-grade metamorphic basement intruded by Ordovician granitoids. These rocks are unconformably covered by a volcano-sedimentary sequence of Miocene age, followed by volcanic and volcaniclastic rocks of Upper Miocene to Plio-Pleistocene age. All these units are cut by two systems of major faults, locally characterized by 15-20 m wide damage zones. The detection of main tectonic lineaments in the study area was firstly carried out by classical procedures: image sharpening of Landsat 7 ETM+ images, directional filters applied to ASTER images, medium resolution Digital Elevation Models analysis (SRTM and ASTER GDEM) and hill shades interpretation. In addition, a new approach in fault zone identification, based on multispectral satellite images classification, has been tested in the Laguna Blanca area and in other sectors of south-central Andes. In this perspective, several prominent fault zones affecting basement and granitoid rocks have been sampled. The collected fault gouge samples have been analyzed with a Field-Pro spectrophotometer mounted on a goniometer. We acquired bidirectional reflectance spectra, from 0.35?m to 2.5?m with 1nm spectral sampling, of the sampled fault rocks. Subsequently, two different Spectral Angle Mapper (SAM) classifications were applied to ASTER images: the first one based on fault rock spectral signatures resampled at the ASTER sensor resolution; the second one based on spectral signatures retrieved from specific Region of Interest (ROI), which were directly derived from the ASTER image on the analyzed fault zones. The SAM classification based on the spectral signatures of fault rocks gave outstanding results since it was able to classify the analyzed fault zone, both in terms of length and width. Moreover, in some specific cases, this SAM classification identified not only the sampled fault zone, but also other prominent neighboring faults cutting the same host rock. These results define the SAM supervised classification on ASTER images as a tool to identify prominent fault zones directly on the base of fault-rocks spectra.

  12. Detecting Land Cover Change by Trend and Seasonality of Remote Sensing Time Series

    Science.gov (United States)

    Oliveira, J. C.; Epiphanio, J. N.; Mello, M. P.

    2013-05-01

    Natural resource managers demand knowledge of information on the spatiotemporal dynamics of land use and land cover change, and detection and characteristics change over time is an initial step for the understanding of the mechanism of change. The propose of this research is the use the approach BFAST (Breaks For Additive Seasonal and Trend) for detects trend and seasonal changes within Normalized Difference Vegetation Index (NDVI) time series. BFAST integrates the decomposition of time series into trend, seasonal, and noise components with methods for detecting change within time series without the need to select a reference period, set a threshold, or define a change trajectory. BFAST iteratively estimates the time and number of changes, and characterizes change by its magnitude and direction. The general model is of the form Yt = Tt + St + et (t= 1,2,3,…, n) where Yt is the observed data at time t, Tt is the trend component, St is the seasonal component, and et is the remainder component. In this study was used MODIS NDVI time series datasets (MOD13Q1) over 11 years (2000 - 2010) on an intensive agricultural area in Mato Grosso - Brazil. At first it was applied a filter for noise reduction (4253H twice) over spectral curve of each MODIS pixel, and subsequently each time series was decomposed into seasonal, trend, and remainder components by BFAST. Were detected one abrupt change from a single pixel of forest and two abrupt changes on trend component to a pixel of the agricultural area. Figure 1 shows the number of phonological change with base in seasonal component for study area. This paper demonstrated the ability of the BFAST to detect long-term phenological change by analyzing time series while accounting for abrupt and gradual changes. The algorithm iteratively estimates the dates and number of changes occurring within seasonal and trend components, and characterizes changes by extracting the magnitude and direction of change. Changes occurring in the seasonal component indicate phenological changes, while changes occurring in the trend component indicate gradual and abrupt change. BFAST can be used to analyze different types of remotely sensed time series and can be applied to other time series such as econometrics, climatology, and hydrology. The algorithm used in this study is available in BFAT package for R from CRAN (http://cran.r-project.org/package=bfast).; Figure 1 - Number of the phonological change with base in seasonal component.

  13. Remote-controlled robotic platform ORPHEUS as a new tool for detection of bacteria in the environment.

    Science.gov (United States)

    Nejdl, Lukas; Kudr, Jiri; Cihalova, Kristyna; Chudobova, Dagmar; Zurek, Michal; Zalud, Ludek; Kopecny, Lukas; Burian, Frantisek; Ruttkay-Nedecky, Branislav; Krizkova, Sona; Konecna, Marie; Hynek, David; Kopel, Pavel; Prasek, Jan; Adam, Vojtech; Kizek, Rene

    2014-08-01

    Remote-controlled robotic systems are being used for analysis of various types of analytes in hostile environment including those called extraterrestrial. The aim of our study was to develop a remote-controlled robotic platform (ORPHEUS-HOPE) for bacterial detection. For the platform ORPHEUS-HOPE a 3D printed flow chip was designed and created with a culture chamber with volume 600 ?L. The flow rate was optimized to 500 ?L/min. The chip was tested primarily for detection of 1-naphthol by differential pulse voltammetry with detection limit (S/N = 3) as 20 nM. Further, the way how to capture bacteria was optimized. To capture bacterial cells (Staphylococcus aureus), maghemite nanoparticles (1 mg/mL) were prepared and modified with collagen, glucose, graphene, gold, hyaluronic acid, and graphene with gold or graphene with glucose (20 mg/mL). The most up to 50% of the bacteria were captured by graphene nanoparticles modified with glucose. The detection limit of the whole assay, which included capturing of bacteria and their detection under remote control operation, was estimated as 30 bacteria per ?L. PMID:24634313

  14. Comparison of ferucarbotran-enhanced MRI and triple-phase MDCT for the detection of hepatocellular carcinoma in advanced liver cirrhosis

    International Nuclear Information System (INIS)

    To compare the diagnostic performance of ferucarbotran-enhanced MRI at 1.5-T with triple-phase multidetector-row helical CT (MDCT) to detect hepatocellular carcinoma in patients with advanced liver cirrhosis. Twenty patients with advanced liver cirrhosis (Child's class B:C = 8:12) underwent ferucarbotran-enhanced MRI and triple-phase MDCT prior to liver transplantation. The mean time interval between the two imaging techniques was 18 days (range, 1-35 days). Three radiologists independently reviewed both images on a lesion-by-lesion basis and interpreted them for comparison with the pathologic findings of the explanted livers. As well, the sensitivity and an alternative-free response receiver operating characteristics (ROC) analysis was used to evaluate the diagnostic performance of each technique. The mean area under the ROC curve (Az) was significantly higher for the triple-phase MDCT (0.766) compared to the ferucarbotran-enhanced MRI (0.675) (? < 0.001). Similarly, the mean sensitivity of the triple-phase MDCT (60.3%) exceeded the ferucarbotran-enhanced MRI (43.1%). The results indicate that the triple-phase MDCT provides significantly greater mean sensitivity than the ferucarbotran-enhanced MRI (? < 0.001). The triple-phase MDCT provided a better diagnostic performance and higher sensitivity than the ferucarbotran-enhanced MRI for the detection of hepatocellular carcinomas in patients with advanced liver cirrhosis

  15. Comparison of ferucarbotran-enhanced MRI and triple-phase MDCT for the detection of hepatocellular carcinoma in advanced liver cirrhosis

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Yong Hwan; Kim, Seung Hoon; Choi, Dong Il; Kim, Min Ju [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Kim, Sam Soo; Lee Ji Won; Han, Heon [Kangwon National University College of Medicine, Chuncheon (Korea, Republic of); Lee, Jong Mee [Korea University Guro Hospital, Seoul (Korea, Republic of)

    2008-01-15

    To compare the diagnostic performance of ferucarbotran-enhanced MRI at 1.5-T with triple-phase multidetector-row helical CT (MDCT) to detect hepatocellular carcinoma in patients with advanced liver cirrhosis. Twenty patients with advanced liver cirrhosis (Child's class B:C = 8:12) underwent ferucarbotran-enhanced MRI and triple-phase MDCT prior to liver transplantation. The mean time interval between the two imaging techniques was 18 days (range, 1-35 days). Three radiologists independently reviewed both images on a lesion-by-lesion basis and interpreted them for comparison with the pathologic findings of the explanted livers. As well, the sensitivity and an alternative-free response receiver operating characteristics (ROC) analysis was used to evaluate the diagnostic performance of each technique. The mean area under the ROC curve (Az) was significantly higher for the triple-phase MDCT (0.766) compared to the ferucarbotran-enhanced MRI (0.675) ({rho} < 0.001). Similarly, the mean sensitivity of the triple-phase MDCT (60.3%) exceeded the ferucarbotran-enhanced MRI (43.1%). The results indicate that the triple-phase MDCT provides significantly greater mean sensitivity than the ferucarbotran-enhanced MRI ({rho} < 0.001). The triple-phase MDCT provided a better diagnostic performance and higher sensitivity than the ferucarbotran-enhanced MRI for the detection of hepatocellular carcinomas in patients with advanced liver cirrhosis.

  16. Detectability of hepatocellular carcinoma on gadoxetic acid-enhanced MRI at 3 T in patients with severe liver dysfunction: clinical impact of dual-source parallel radiofrequency excitation

    International Nuclear Information System (INIS)

    Aim: To clarify the detectability of hepatocellular carcinoma (HCC) on gadoxetic acid-enhanced MRI at 3 T with dual-source parallel radiofrequency (RF) excitation. Materials and methods: Twelve patients with 26 HCCs who each underwent multidetector row CT (MDCT), gadoxetic acid-enhanced MRI with dual-source parallel RF excitation, and angiography-assisted CT prior to living related-liver transplantation. Three blinded readers independently reviewed the images obtained by each imaging technique for the presence of HCC on a segment-by-segment basis using a five-point confidence scale. The area under the receiver operating characteristic curve (Az), sensitivity, and specificity were compared among the three techniques. Results: The Az values of gadoxetic acid-enhanced MRI were highest for all readers, although no significant difference in Az value among the three methods was obtained. No significant differences in sensitivity or specificity were observed among the three techniques for each reader. Conclusion: Gadoxetic acid-enhanced MRI at 3 T with dual-source parallel RF excitation has relatively high-level diagnostic potential for the detection of HCC in patients with severe liver dysfunction, which was equivalent to that of MDCT and angiography-assisted CT. Dual-source parallel RF excitation would have a clinical impact on 3 T MRI of the liver. - Highlights: • Dual-source parallel RF excitation improves lesion detectability at 3.0 Tesla MRI. • This system eliminates dielectric shading formed by a large amount of ascites. • 3.0 Tesla MRI with this system has equivalent lesion detectability to 1.5 Tesla

  17. Clinical value of periventricular low-intensity areas detected by fluid attenuated inversion recovery (FLAIR). Relationships between MRI at near term and long-distant outcome

    International Nuclear Information System (INIS)

    We performed an MRI (magnetic resonance imaging) study of neonatal brain to assess the clinical value of periventricular low intensities (PVLI) detected on FLAIR (fluid attenuated inversion recovery) imaging in 280 preterm and term infants. The incidence of PVLI was 62% on early MRI, obtained before two-months corrected age, and it decreased to 3% and 0% on middle (2-8 months) and late (8-18 months) MRI. On middle and late MRI, we observed periventricular hyperintensities (PVHI) both on FLAIR imaging and T2-weighted imaging, which were considered to be chronic lesions of leukomalacia. The severity of white matter damage diagnosed on early FLAIR imaging had a significant correlation with that of late FLAIR imaging. We conclude that early FLAIR imaging would be a good predictor of chronic white matter damage that may influence the motor and mental development of the infants. (author)

  18. Detection of Usefullness of Integrating Remotely Sensed Data (Landsat TM with GIS

    Directory of Open Access Journals (Sweden)

    H. Abdul Halim

    2006-01-01

    Full Text Available A study integrating remote sensing and Geographical Information System (GIS was carried out in the Kuala Terengganu district, Terengganu, Malaysia to map and determine the land use change as a result of development pressure in the area. Two sets of Landsat Thematic Mapper (TM dated 31 July 1988 and 14 July 2002, at scale 1: 150 000 were acquired. Land use classes were interpreted from these images and the resultant maps were checked in the field to determine ground truth and mapping accuracy. The land use map data were transferred directly into the computer via ILWIS (Integrated Land Water and Water Information System version 3.1 software. It shown that in this study seven categories of land use changes were detected namely forest (-9.93%, agricultural (-1.46%, swamp (-36.92%, urban (190.29%, cleared land (-21.43%, water bodies (-7.48% and bush/shrub (6.34%. The accuracy assessment undertaken showed that the total accuracy for produced the map is 77.89%. This study showed that Landsat TM is a useful data for study in land use change.

  19. Remote sensing for greenhouse detection from stereo pairs of WorldView-2 satellite

    Directory of Open Access Journals (Sweden)

    M.A. Aguilar

    2014-05-01

    Full Text Available The successful launch of the first very high resolution (VHR satellites capable of capturing panchromatic imagery of the land surface with ground sample distance even lower than 1 m (e.g. IKONOS in 1999 or QuickBird in 2001 marked the beginning of a wholly new age in remote sensing. On January 4, 2010, images of WorldView-2 were placed on the market. Possibly it is the most sophisticated commercial VHR satellite currently orbiting the Earth and the exploitation of its data poses a challenge to researchers worldwide. Moreover, the practice of under plastic agriculture had a great development in the Mediterranean area during the past 60 years, especially in Almeria, acting as a key economic driver in the area. The goal of this work is the automatic greenhouse mapping by using Object Based Image Analysis (OBIA. The required input data will be a pan-sharpened orthoimage and a normalized digital surface model (nDSM for objects, both products generated from a WorldView-2 stereo pair. The attained results show that the very high resolution 8-band multispectral and the nDSM data improve the greenhouses automatic detection. In this way, overall accuracies higher than 90% can be achieved.

  20. Remote detection of physiological depression in crop plants with infrared thermal imagery

    International Nuclear Information System (INIS)

    The infrared thermal imagery was measured concurrently with physiological status in stressed and non-stressed corn and wheat canopies. Thermal images were obtained with an infrared thermography system from a distance of 5 to 20 m. Each thermal image, composed of 512 (H) × 240 (V) pixels with a sensitivity of 0.05°C, was recorded in a video tape every 8 seconds in the field, and analyzed in a laboratory later. A root-reducing treatment was used for simulating environmental stresses, which treatment was carried out by cutting a root system with a thin metal plate at the depth of 20 cm, but brought little apparent change in plant stands. Photosynthesis, transpiration and stomatal conductance in the stressed canopy were depressed, which were accompanied with an inverse change in the canopy surface temperature. The maximum difference in mean surface temperatures of the stressed and non-stressed parts of the canopy was no less than 4.2°C in corn and 3.1°C in wheat. Gaussian distribution of spatial temperature frequency in the stressed part shifted toward higher temperature from that of non-stressed part of the canopy, which was visualized clearly on the pseudo-color thermal image while no visible changes were observed directly from the distance. The infrared imagery was effective, especially, for detecting phisiological depression or for comparing various canopies in their physiological status on a remote and real-time basis

  1. DETECTION OF COASTAL GEOMORPHOLOGICAL CHANGES FOR EFFECTIVE COASTAL MANAGEMENT USING REMOTE SENSING & GIS

    Directory of Open Access Journals (Sweden)

    SS.Asadi

    2015-02-01

    Full Text Available The present study deals with the Geomorphological changes Detection study in Pulicat Lagoon. The study involves identifying the geomorphologic changes occurred due to the natural disasters and man made activities using 2008, 2010, 2013 satellite Images by adopting Remote Sensing Technologies and GIS tools. The study area is located in Nellore district of Andhra Pradesh, India located between longitude 80° 3?3? to 80° 18?6? and 13 °28? 32? to 13° 57?6? latitude. The study area is covered under the Survey of India (SOI toposheet no 66C/1,2,3,5,6 and 7 with scale 1:50000 and Multi-Spectral imageries from IRS-P6,LISS III,IV data of 2008, 2010 and 2013 Geocoded Satellite data are acquired as primary and secondary data for analysis. Visual Interpretation techniques are used to identify the Geomorphology classes from 2008, 2010 satellite imageries, ground truthing and post interpretation of the satellite image for preparation of 2013 Geomorphology map in this different classes like Creek, Flood Plain, Coastal Plain Moderate, Buried Pedi plain etc. are identified. These spatial data maps generate statistical values of geomorphological classes, from this data analysis was carried out to find out the changes in the Geomorphology classes of 2008 to 2010 and 2010 to 2013. These type of model studies are very useful to identify the coastal geomorphological changes, its impact on coastal environment and in preparing the action plans to protect the coastal environmental.

  2. Can the painDETECT Questionnaire score and MRI help predict treatment outcome in rheumatoid arthritis

    DEFF Research Database (Denmark)

    Rifbjerg-Madsen, Signe; Christensen, Anton Wulf; Boesen, Mikael; Christensen, Robin; Danneskiold-Samsøe, Bente; Bliddal, Henning; Bartels, Else Marie; Locht, Henning; Amris, Kirstine

    2014-01-01

    INTRODUCTION: Pain in rheumatoid arthritis (RA) is traditionally considered to be of inflammatory origin. Despite better control of inflammation, some patients still report pain as a significant concern, even when being in clinical remission. This suggests that RA may prompt central sensitisation......-inflammatory treatment, to explore the prognostic value of a screening questionnaire for central sensitisation, hand inflammation assessed by conventional MRI, and the interaction between them regarding treatment outcome evaluated by clinical status (DAS28-CRP). For the purpose of further exploratory analyses, dynamic...

  3. Efficient pro-survival/angiogenic miRNA delivery by an MRI-detectable nanomaterial.

    OpenAIRE

    Gomes, RS; das Neves, RP; Cochlin, L; A Lima; Carvalho, R; P Korpisalo; Dragneva, G; Turunen, M.; Liimatainen, T; Clarke, K.; Ylä-Herttuala, S.; Carr, C.; Ferreira, L

    2013-01-01

    Herein, we report the use of biodegradable nanoparticles (NPs) containing perfluoro-1,5-crown ether (PFCE), a fluorine-based compound (NP170-PFCE) with the capacity to track cells in vivo by magnetic ressonance imaging (MRI) and efficiently release miRNA. NP170-PFCE complexed with miRNAs accumulate whitin the cell's endolysosomal compartment and interact with higher frequency with argonaute2 (Ago2) and GW182 proteins, which are involved in the biological action of miRNAs, than commercial comp...

  4. Remote Sensing of Martian Terrain Hazards via Visually Salient Feature Detection

    Science.gov (United States)

    Al-Milli, S.; Shaukat, A.; Spiteri, C.; Gao, Y.

    2014-04-01

    The main objective of the FASTER remote sensing system is the detection of rocks on planetary surfaces by employing models that can efficiently characterise rocks in terms of semantic descriptions. The proposed technique abates some of the algorithmic limitations of existing methods with no training requirements, lower computational complexity and greater robustness towards visual tracking applications over long-distance planetary terrains. Visual saliency models inspired from biological systems help to identify important regions (such as rocks) in the visual scene. Surface rocks are therefore completely described in terms of their local or global conspicuity pop-out characteristics. These local and global pop-out cues are (but not limited to); colour, depth, orientation, curvature, size, luminance intensity, shape, topology etc. The currently applied methods follow a purely bottom-up strategy of visual attention for selection of conspicuous regions in the visual scene without any topdown control. Furthermore the choice of models used (tested and evaluated) are relatively fast among the state-of-the-art and have very low computational load. Quantitative evaluation of these state-ofthe- art models was carried out using benchmark datasets including the Surrey Space Centre Lab Testbed, Pangu generated images, RAL Space SEEKER and CNES Mars Yard datasets. The analysis indicates that models based on visually salient information in the frequency domain (SRA, SDSR, PQFT) are the best performing ones for detecting rocks in an extra-terrestrial setting. In particular the SRA model seems to be the most optimum of the lot especially that it requires the least computational time while keeping errors competitively low. The salient objects extracted using these models can then be merged with the Digital Elevation Models (DEMs) generated from the same navigation cameras in order to be fused to the navigation map thus giving a clear indication of the rock locations.

  5. Surface biosignatures of exo-earths: remote detection of extraterrestrial life.

    Science.gov (United States)

    Hegde, Siddharth; Paulino-Lima, Ivan G; Kent, Ryan; Kaltenegger, Lisa; Rothschild, Lynn

    2015-03-31

    Exoplanet discovery has made remarkable progress, with the first rocky planets having been detected in the central star's liquid water habitable zone. The remote sensing techniques used to characterize such planets for potential habitability and life rely solely on our understanding of life on Earth. The vegetation red edge from terrestrial land plants is often used as a direct signature of life, but it occupies only a small niche in the environmental parameter space that binds life on present-day Earth and has been widespread for only about 460 My. To more fully exploit the diversity of the one example of life known, we measured the spectral characteristics of 137 microorganisms containing a range of pigments, including ones isolated from Earth's most extreme environments. Our database covers the visible and near-infrared to the short-wavelength infrared (0.35-2.5 µm) portions of the electromagnetic spectrum and is made freely available from biosignatures.astro.cornell.edu. Our results show how the reflectance properties are dominated by the absorption of light by pigments in the visible portion and by strong absorptions by the cellular water of hydration in the infrared (up to 2.5 µm) portion of the spectrum. Our spectral library provides a broader and more realistic guide based on Earth life for the search for surface features of extraterrestrial life. The library, when used as inputs for modeling disk-integrated spectra of exoplanets, in preparation for the next generation of space- and ground-based instruments, will increase the chances of detecting life. PMID:25775594

  6. Detection and mapping of oil-contaminated soils by remote sensing of laser-induced fluorescence

    Science.gov (United States)

    Luedeker, Wilhelm; Guenther, Kurt P.; Dahn, Hans-Guenter

    1995-10-01

    The contamination of soil by aromatic mineral hydrocarbons (MHC) (e.g., gasoline, oil, etc.) has become a severe environmental problem because not only men, animals, and plants are threatened but also the water and air. With the unification of Germany a great number of suspected contaminated sites in the new countries were registered. An estimation of the German Federal Ministry of Environment (BMU) counts 180,000 areas contaminated with different pollutants, 55,000 are situated in the former GDR. On military settlements for example more than fifty percent of the chemicals are MHCs. Hence one can get an idea of the importance of soil pollution by hydrocarbons. Other zones contaminated due to carelessness or accidents are civil petrolstations, airports, refineries, pipelines, and traffic disasters. At the present time for most of these areas the contamination is assumed due to recent use. Due to the large extension of the problem an estimation and evaluation of the potential hazard for the environment is difficult and expensive to perform. In the case of an actual endangering the total area must be mapped in detail resulting in increasing costs for the owner. Nevertheless it is necessary to find reliable timesaving areal mapping and monitoring methods. One opportunity presented in this paper is the application of remote sensing by laser induced fluorescence from an airborne platform. It promises to fulfill these requirements in a sufficiently fast manner with very high spatial resolution. The access to the pollutant detection is the specific laser induced fluorescence emitted by the MHC (finger print). The present work shows the requirements for a helicopterborne lidar system for MHC mapping and how the detected signals are to be evaluated and interpreted.

  7. Development of Ecogenomic Sensors for Remote Detection of Marine Microbes, Their Genes and Gene Products

    Science.gov (United States)

    Scholin, C.; Preston, C.; Harris, A.; Birch, J.; Marin, R.; Jensen, S.; Roman, B.; Everlove, C.; Makarewicz, A.; Riot, V.; Hadley, D.; Benett, W.; Dzenitis, J.

    2008-12-01

    An internet search using the phrase "ecogenomic sensor" will return numerous references that speak broadly to the idea of detecting molecular markers indicative of specific organisms, genes or other biomarkers within an environmental context. However, a strict and unified definition of "ecogenomic sensor" is lacking and the phrase may be used for laboratory-based tools and techniques as well as semi or fully autonomous systems that can be deployed outside of laboratory. We are exploring development of an ecogenomic sensor from the perspective of a field-portable device applied towards oceanographic research and water quality monitoring. The device is known as the Environmental Sample Processor, or ESP. The ESP employs wet chemistry molecular analytical techniques to autonomously assess the presence and abundance of specific organisms, their genes and/or metabolites in near real-time. Current detection chemistries rely on low- density DNA probe and protein arrays. This presentation will emphasize results from 2007-8 field trials when the ESP was moored in Monterey Bay, CA, as well as current engineering activities for improving analytical capacity of the instrument. Changes in microbial community structure at the rRNA level were observed remotely in accordance with changing chemical and physical oceanographic conditions. Current developments include incorporation of a reusable solid phase extraction column for purifying nucleic acids and a 4-channel real-time PCR module. Users can configure this system to support a variety of PCR master mixes, primer/probe combinations and control templates. An update on progress towards fielding a PCR- enabled ESP will be given along with an outline of plans for its use in coastal and oligotrophic oceanic regimes.

  8. Detection and mapping of oil contaminated soils by remote sensing of laser induced fluorescence

    International Nuclear Information System (INIS)

    The contamination of soil by aromatic mineral hydrocarbons (MHC) (e.g. gasoline, oil etc) has become a severe environmental problem because not only men, animals and plants are threatened but also the water and air. With the unification of Germany a great number of suspected contaminated sites in the new counties were registered. An estimation of the German Federal Ministry of Environment (BMU) counts 180,000 areas contaminated with different pollutants, 55,000 are situated in the former GDR. On military settlements for example more than fifty percent of the chemicals are MHC's. Hence one can get an idea of the importance of soil pollution by hydrocarbons. Other zones contaminated due to carelessness or accidents are civil petrolstations, airports, refineries, pipelines and traffic disasters. At the present time for most of these areas the contamination is assumed due to recent use. Due to the large extension of the problem an estimation and evaluation of the potential hazard for the environment is difficult and expensive to perform. In the case of actual endangering the total area must be mapped in detail and expensive to perform. In the case of an actual endangering the total area must be mapped in detail resulting in increasing costs for the owner. Nevertheless it is necessary to find reliable timesaving areal mapping and monitoring methods. One opportunity presented in this paper is the application of remote sensing by laser induced fluorescence from an airborne platform. It promises to fulfill these requirements in a sufficient fast manner with very high spatial resolution. The access to the pollutant detection is the specific laser inducted fluorescence omitted by the MHC (finger print). The present work shows the requirements for a helicopter-borne lidar system for MHC mapping and how the detected signals are to be evaluated and interpreted

  9. Remote Detection of Concealed Radioactive Materials by Using Focused Powerful Terahertz Radiation

    Science.gov (United States)

    Nusinovich, Gregory S.

    2016-02-01

    This review paper summarizes the results of studies of a novel concept of the remote detection of concealed radioactive materials by using focused high-power terahertz (THz) radiation. The concept is based on the known fact that the ambient electron density in air is low (one to three free electrons per cubic centimeter). These electrons can serve as seed electrons from which an avalanche breakdown in strong electromagnetic fields starts. When a powerful THz radiation is focused in a small spot, the breakdown-prone volume can be much smaller than a cubic centimeter. So, the probability of having some free electrons in this volume and, hence, the probability of breakdown are low in the absence of additional sources of air ionization. However, in the vicinity of radioactive materials (10-20 m), the electron density can be higher, and, hence, there are always some seed free electrons from which the avalanche ionization will start. Thus, the breakdown rate in this case can be close to 100 %. Realization of this concept requires studies of various physical and technical issues. First, it is necessary to develop a high-power source of (sub-) THz radiation whose power, frequency, and pulse duration are sufficient for realizing this goal. Second, it is necessary to analyze numerous issues important for realizing this concept. Among these issues are (a) enhancement of the ionization level of air molecules in the presence of hidden radioactive materials, (b) estimating the minimum detectable mass of radioactive material, (c) formation of breakdown-prone volumes in focused THz wave beams, and (d) effect of atmospheric conditions on the propagation and focusing of THz wave beams and on the optimal location of the breakdown-prone volume between a container with hidden radioactive material and a THz antenna. The results of these studies are described below.

  10. MRI at 3 Tesla detects no evidence for ischemic brain damage in intensively treated patients with homozygous familial hypercholesterolemia

    International Nuclear Information System (INIS)

    Homozygous familial hypercholesterolemia (FH) is considered a model disease for excessive plasma cholesterol levels. Patients with untreated homozygous FH have a markedly increased risk for premature atherosclerosis. The frequency and extent of ischemic brain damage detectable by high-field magnetic resonance imaging (MRI) after long-term intensive treatment are unknown. In a case control study, five patients with homozygous FH (one male and four females; mean age: 23.6 ± 9.2, range: 12-36 years; mean pre-treatment serum total cholesterol level: 26.9 ± 3.24 mmol/L; all patients with documented atherosclerotic plaques in the carotid arteries) and five age- and sex-matched healthy controls were studied. All patients had been on maximal lipid-lowering medication since early childhood, and four of them were also on treatment with low-density lipoprotein (LDL) apheresis at bi-weekly intervals. Brain MRI was performed at 3 Tesla field strength with fluid-attenuated T2-weighted inversion recovery and T1-weighted spin-echo MR pulse sequences and subsequently evaluated by two independent readers. The maximal lipid-lowering treatment reduced the total serum cholesterol by more than 50% in the patients, but their serum concentrations were still 3.6-fold higher than those found in the controls (11.9 ± 4.2 vs. 4.5 ± 0.5 mmol/L; p < 0.0047). No brain abnormality was observed in any of the patients with homozygous FH. Homozygous FH patients on intensive cholesterol-lowering therapy have no evidence of ischemic brain damage at 3 Tesla MRI despite the remaining high cholesterol levels. (orig.)

  11. MRI at 3 Tesla detects no evidence for ischemic brain damage in intensively treated patients with homozygous familial hypercholesterolemia

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, Stephan A.; O' Regan, Declan P.; Fitzpatrick, Julie; Hajnal, Joseph V. [Hammersmith Hospital Campus, Imaging Sciences Department, MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College, London (United Kingdom); Neuwirth, Clare; Potter, Elizabeth; Tosi, Isabella; Naoumova, Rossi P. [MRC Clinical Sciences Centre, Clinical Research Facility, London (United Kingdom); Hammersmith Hospital, Lipid Clinic, London (United Kingdom)

    2007-11-15

    Homozygous familial hypercholesterolemia (FH) is considered a model disease for excessive plasma cholesterol levels. Patients with untreated homozygous FH have a markedly increased risk for premature atherosclerosis. The frequency and extent of ischemic brain damage detectable by high-field magnetic resonance imaging (MRI) after long-term intensive treatment are unknown. In a case control study, five patients with homozygous FH (one male and four females; mean age: 23.6 {+-} 9.2, range: 12-36 years; mean pre-treatment serum total cholesterol level: 26.9 {+-} 3.24 mmol/L; all patients with documented atherosclerotic plaques in the carotid arteries) and five age- and sex-matched healthy controls were studied. All patients had been on maximal lipid-lowering medication since early childhood, and four of them were also on treatment with low-density lipoprotein (LDL) apheresis at bi-weekly intervals. Brain MRI was performed at 3 Tesla field strength with fluid-attenuated T2-weighted inversion recovery and T1-weighted spin-echo MR pulse sequences and subsequently evaluated by two independent readers. The maximal lipid-lowering treatment reduced the total serum cholesterol by more than 50% in the patients, but their serum concentrations were still 3.6-fold higher than those found in the controls (11.9 {+-} 4.2 vs. 4.5 {+-} 0.5 mmol/L; p < 0.0047). No brain abnormality was observed in any of the patients with homozygous FH. Homozygous FH patients on intensive cholesterol-lowering therapy have no evidence of ischemic brain damage at 3 Tesla MRI despite the remaining high cholesterol levels. (orig.)

  12. In vivo detection of the effects of preconditioning on LNCaP tumors by a TNF-? nanoparticle construct using MRI.

    Science.gov (United States)

    Iltis, Isabelle; Choi, Jeunghwan; Vollmers, Manda; Shenoi, Mithun; Bischof, John; Metzger, Gregory J

    2014-09-01

    The outcome of systemic and local therapies (e.g. chemotherapy, radiotherapy, surgery, focal ablation) for prostate cancer can be significantly improved by using tumor-specific adjuvants prior to treatment ("preconditioning"). We propose to use dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) to monitor the in vivo response of a mouse model of prostate cancer treated with a vascular disruptive agent, TNF-?, delivered on a gold nanoparticle (NP-TNF). Six male nude mice bearing 4-5 week old LNCaP tumors were scanned at 9.4 T. DCE-MRI was performed two days before and 4-5 h after treatment with NP-TNF. An intraperitoneal (i.p.) bolus of gadolinium-DTPA (Gd) was administered and contrast enhancement was measured for 90 min. Concentration-time curves of Gd were calculated and the area under the Gd curve (AUGC) was determined pre- and post-treatment. NP-TNF treatment caused an increase in contrast uptake in tumors. Interestingly, the early concentration (10 min post Gd bolus i.p.) was similar in both untreated and treated conditions; however, 90 min after injection, [Gd] was 3.4 times higher than before treatment. AUGC doubled from (11 ± 6) [Gd] × min before treatment to (22 ± 9) [Gd] × min after treatment. An increase in signal enhancement was also observed in the muscle but to a lesser degree. We also evaluated the kinetics of intravenous Gd administration in mice bearing a jugular vein catheter to mimic the delivery method used in clinical trials. The overall treatment effects were independent of the delivery pathway of the contrast agent. In conclusion, we show that DCE-MRI is suitable to detect changes associated with a vascular disruptive agent in a mouse model of prostate cancer. The ability to characterize the effects of nanoparticle therapy in vivo with non-destructive methods is important, as such compounds, in combination with treatment strategies, are progressing towards clinical trials. PMID:24980267

  13. Upper abdominal gadoxetic acid-enhanced and diffusion-weighted MRI for the detection of gastric cancer: Comparison with two-dimensional multidetector row CT

    International Nuclear Information System (INIS)

    Aim: To evaluate the diagnostic performance of abdominal magnetic resonance imaging (MRI) for the detection of gastric cancer in comparison with that of two-dimensional (2D) multidetector row computed tomography (CT). Materials and methods: The study included 189 patients with 170 surgically confirmed gastric cancers and 19 patients without gastric cancer, all of whom underwent gadoxetic acid-enhanced MRI with diffusion-weighted (DW) imaging, and multidetector contrast-enhanced abdominal CT imaging. Two observers independently analysed three sets of images (CT set, conventional MRI set, and combined conventional and DW MRI set). A five-point scale for likelihood of gastric cancer was used. Diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were evaluated. Quantitative [apparent diffusion coefficient (ADC) analyses with Mann–Whitney U-test were conducted for gastric cancers and the nearby normal gastric wall. Results: The diagnostic accuracy and sensitivity for detection of gastric cancer were significantly higher on combined conventional and DW MRI set (77.8–78.3%; 75.3–75.9%) than the CT imaging set (67.7–71.4%; 64.1–68.2%) or the conventional MRI set (72–73%; 68.8–70%; p < 0.01). In particular, for gastric cancers with pT2 and pT3, the combined conventional and DW MRI set (91.6–92.6%) yielded significantly higher sensitivity for detection of gastric cancer than did the CT imaging set (76.8–81.1%) by both observers (p < 0.01). The mean ADC of gastric cancer lesions (1 ± 0.23 × 10?3mm2/s) differed significantly from that of normal gastric wall (1.77 ± 0.25 × 10?3 mm2/s; p < 0.01). Conclusion: Abdominal MRI with DW imaging was more sensitive for the detection of gastric cancer than 2D-multidetector row CT or conventional MRI alone. - Highlights: • The sensitivity for detection of gastric cancer is high on abdominal MR imaging. • DW imaging is helpful for detection of gastric cancer. • The stomach should be scrutinized on abdominal MR imaging

  14. Integrated microchip incorporating atomic magnetometer and microfluidic channel for NMR and MRI

    Science.gov (United States)

    Ledbetter, Micah P. (Oakland, CA); Savukov, Igor M. (Los Alamos, NM); Budker, Dmitry (El Cerrito, CA); Shah, Vishal K. (Plainsboro, NJ); Knappe, Svenja (Boulder, CO); Kitching, John (Boulder, CO); Michalak, David J. (Berkeley, CA); Xu, Shoujun (Houston, TX); Pines, Alexander (Berkeley, CA)

    2011-08-09

    An integral microfluidic device includes an alkali vapor cell and microfluidic channel, which can be used to detect magnetism for nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI). Small magnetic fields in the vicinity of the vapor cell can be measured by optically polarizing and probing the spin precession in the small magnetic field. This can then be used to detect the magnetic field of in encoded analyte in the adjacent microfluidic channel. The magnetism in the microfluidic channel can be modulated by applying an appropriate series of radio or audio frequency pulses upstream from the microfluidic chip (the remote detection modality) to yield a sensitive means of detecting NMR and MRI.

  15. Detection of contralateral normal ovary in patients with large(>10 cm) unilateral ovarian mass by using MRI

    International Nuclear Information System (INIS)

    To assess the usefulness of MRI for determining the presence of a large (> 10 cm) unilateral ovarian tumor by detecting the existence of a normal contralateral ovary, and to establish the difference in detection rates between premenopausal and postmenopausal women, and benign and malignant tumors. Forty-two patients who underwent MR imaging and in whom the intraoperative gross and pathologic findings indicated the presence of a unilateral ovarian mass and a normal contralateral ovary were included in this study. The images obtained were retrospectively analyzed by two radiologists, who determined the detection rate of the normal contralateral ovary and whether this differed between premenopausal and postmenopausal women, and benign and malignant tumors. Contralateral normal ovaries were detected in 35 (83.3%) of 42 patients [22 of 23 ovaries (95.7%) in premenopausal women and 13 of 19 (68.4%) in postmenopausal women], with a statistically significant difference (p=0.018). Twelve of 16 of these ovaries (75%) were present in women with malignant tumors, and 23 (88.5%) of 26 in those with benign tumors, but the difference was not statistically significant (p=0.256). MR imaging is useful for detecting a normal contralateral ovary and for determining the site at which a large (> 10 cm) unilateral ovarian tumor originates, especially in premenopausal women

  16. IMAGE PROCESSING AND REMOTE SENSING – A LULC CHANGE DETECTION USING REMOTELY SENSED DATA FOR COIMBATORE DISTRICT, INDIA

    Directory of Open Access Journals (Sweden)

    Dr.K. Thanushkodi, Y. Baby Kalpana, M. Sharrath

    2012-12-01

    Full Text Available Land Use is clearly constrained by environmental factors like soil characteristics, climatic conditions, water sources and vegetation. Changes in Land Use and Land Cover is a dynamic process taking place on the earth surface, and the spatial distribution of the changes that have taken place over a period of time and space is of immense importance in many natural studies. Whether regional or local in scope, remote sensing offers a means of acquiring and presenting land cover data in timely manner. The environmental factors reflect the importance of land as a key and finite resource for most human activities including agriculture, industry, forestry, energy production, settlement, recreation and water sources and storage.Often improper land use is causing various forms of environmental humiliation. For sustainable utilization of the land ecosystems, it is essential to know the natural characteristics, extent and location, its quality, productivity, suitability and limitations of various land uses. Land use is a product of interactions between a society’s cultural background, state and itsphysical needs on the one hand, and the natural potential of land on the other. In order to improve the economic condition of the area without further deteriorating the bio environment, every bit of the available land has to be used in the most rational way. This requires the present and the past land use/land cover data of the Coimbatore district.Land use / Land cover change has become an important component in current strategies for managing natural resources and monitoring environmental changes. The advancement in the concept of vegetation of the spread and health of the world’s forest, grassland and agricultural resources has become an important priority. Viewing the earth from space is now crucial to the understanding of the influence of man’s activities on his natural resource base over time. Over past years, data fromEarth sensing satellites (digital imagery has become vital in mapping the Earth’s features and infrastructures, managing natural resources and studying environmental change.

  17. Effective artifact removal in resting state fMRI data improves detection of DMN functional connectivity alteration in Alzheimer's disease

    Science.gov (United States)

    Griffanti, Ludovica; Dipasquale, Ottavia; Laganà, Maria M.; Nemni, Raffaello; Clerici, Mario; Smith, Stephen M.; Baselli, Giuseppe; Baglio, Francesca

    2015-01-01

    Artifact removal from resting state fMRI data is an essential step for a better identification of the resting state networks and the evaluation of their functional connectivity (FC), especially in pathological conditions. There is growing interest in the development of cleaning procedures, especially those not requiring external recordings (data-driven), which are able to remove multiple sources of artifacts. It is important that only inter-subject variability due to the artifacts is removed, preserving the between-subject variability of interest—crucial in clinical applications using clinical scanners to discriminate different pathologies and monitor their staging. In Alzheimer's disease (AD) patients, decreased FC is usually observed in the posterior cingulate cortex within the default mode network (DMN), and this is becoming a possible biomarker for AD. The aim of this study was to compare four different data-driven cleaning procedures (regression of motion parameters; regression of motion parameters, mean white matter and cerebrospinal fluid signal; FMRIB's ICA-based Xnoiseifier—FIX—cleanup with soft and aggressive options) on data acquired at 1.5 T. The approaches were compared using data from 20 elderly healthy subjects and 21 AD patients in a mild stage, in terms of their impact on within-group consistency in FC and ability to detect the typical FC alteration of the DMN in AD patients. Despite an increased within-group consistency across subjects after applying any of the cleaning approaches, only after cleaning with FIX the expected DMN FC alteration in AD was detectable. Our study validates the efficacy of artifact removal even in a relatively small clinical population, and supports the importance of cleaning fMRI data for sensitive detection of FC alterations in a clinical environment. PMID:26321937

  18. Impact of functional MRI data preprocessing pipeline on default-mode network detectability in patients with disorders of consciousness

    Directory of Open Access Journals (Sweden)

    Adrian Andronache

    2013-08-01

    Full Text Available An emerging application of resting-state functional MRI is the study of patients with disorders of consciousness (DoC, where integrity of default-mode network (DMN activity is associated to the clinical level of preservation of consciousness. Due to the inherent inability to follow verbal instructions, arousal induced by scanning noise and postural pain, these patients tend to exhibit substantial levels of movement. This results in spurious, non-neural fluctuations of the blood-oxygen level-dependent (BOLD signal, which impair the evaluation of residual functional connectivity. Here, the effect of data preprocessing choices on the detectability of the DMN was systematically evaluated in a representative cohort of 30 clinically and etiologically heterogeneous DoC patients and 33 healthy controls. Starting from a standard preprocessing pipeline, additional steps were gradually inserted, namely band-pass filtering, removal of co-variance with the movement vectors, removal of co-variance with the global brain parenchyma signal, rejection of realignment outlier volumes and ventricle masking. Both independent-component analysis (ICA and seed-based analysis (SBA were performed, and DMN detectability was assessed quantitatively as well as visually. The results of the present study strongly show that the detection of DMN activity in the sub-optimal fMRI series acquired on DoC patients is contingent on the use of adequate filtering steps. ICA and SBA are differently affected but give convergent findings for high-grade preprocessing. We propose that future studies in this area should adopt the described preprocessing procedures as a minimum standard to reduce the probability of wrongly inferring that DMN activity is absent.

  19. [An advantage of T2*-weighted MRI for early detection of straight sinus thrombosis: a case report].

    Science.gov (United States)

    Saito, Satoshi; Takahashi, Makio; Nonoguchi, Naosuke; Ohta, Tsuyoshi; Takahashi, Jun A; Matsumoto, Sadayuki

    2009-10-01

    A 44-year-old man presented with a 12-day history of severe non-throbbing headache. He showed no physical abnormality but obesity. On day 12, ring-shaped low intensity lesions inside straight sinus were revealed on T2*-weighted MRI image (T2*WI). On the following day (day 13), he was found unresponsive at home, and ambulated with disturbed consciousness. FLAIR and diffusion-weighted MRI image disclosed high intensity signals in bilateral thalamus which were postulated as vasogenic edema. MR venography and conventional cerebral angiography showed an absence of flow in inferior sagittal sinus, vein of Galen, and straight sinus. These findings confirmed the diagnosis of cerebral venous thrombosis (CVT). Anticoagulant treatment was introduced and his consciousness level was gradually improved. On day 43, he was discharged with no neurological sequelae. A delay of correct diagnosis and treatment with CVT can lead to devastating disability or even to death. An early diagnosis of CVT is often dismissed owing to the nonspecific symptoms such as headache and nausea. Recent reports described high sensitivity of T2*WI for detecting CVT. Alterations in blood flow and oxyhemoglobin reduced products, deoxyhemoglobin, in thrombosed veins often produce the magnetic susceptibility on T2*WI. A detection of ring-shaped low intensity lesions within venous sinus on T2*WI were quite rare, and the signal changes of these sinus lesions were successfully visualized by chronological T2*WI. Taken together, our case implies that T2*WI is the powerful tool for the early detection of CVT, even before the critical symptoms might happen. PMID:19999146

  20. Dynamic contrast-enhanced MRI for the detection of testicular ischemia in experimental induced testicular torsion of rabbits

    International Nuclear Information System (INIS)

    Objective: To evaluate the dynamic contrast-enhanced MRI (DCE-MRI) in detecting experimentally induced testicular ischemia. Methods: Thirty healthy male New Zealand rabbits were randomly assigned into 6 groups. There were 5 rabbits in each of the following experimental groups: (1) Normal control, (2) Sham-operated, (3) ischemia of 3 h group, (4) ischemia of 6 h group, (5) ischemia of 12 h group, (6) ischemia of 24 h group. In all experiment groups, the right testis served as the internal control while the left testis served as the experimental side. DCE-MRI for each animal lasts about 10 minutes. Signal enhanced ratios (SERs) of ROI for both sides of each group were calculated by a computer, and parameters of SERs of 30 s, 75 s, 120 s and maximal SER were used for statistical analysis. Time intensity curves (TICs) were made for two sides of each group via Excel 2003 software and classified into 4 types. Statistical analysis was performed to compare the differences of SERs between left and right testis by two independent Kolmogorov-Smirnov test. Results: In group 1 and 2, significant enhancement was observed on both testes of 10 rabbits. The enhancement decreased gradually with the elongation of ischemia in torsion groups. Three cases of type ? and 2 cases of type ? were observed in group 1, 5 cases of type ? in group two, 2 cases of type ? and 3 cases of type ? b in group three, 2 cases of type ? and 2 cases of type ? b in group four, 5 cases of type b in group five and 5 cases of type ? in group six were noticed in the left testes. And in TICs of right testes, all cases showed TICs of type ? except 2 cases of type ? a in group six. In four torsion groups, the values for SER75 of the left side were 0.084%, 0.076%, 0.164% and 0.065%, while the right side were 0.255%, 0.410%, 0.586% and 0.302% (P120 in group three, five and six were 0.221%, 0.158% and 0.059% for the left side, and 0.405%, 0.522% and 0.207% for the right side (P<0.05). The values for MSER in group three, five and six were 0.217%, 0.164% and 0.072% for the left side, and 0.405%, 0.586% and 0.302% for the right side (P <0.05). Conclusion: DCE-MRI technique may be useful in the diagnosis of testicular torsion, which shows potential in the clinical application. (authors)