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1

Amplification of xenon NMR and MRI by remote detection  

Science.gov (United States)

A technique is proposed in which an NMR spectrum or MRI is encoded and stored as spin polarization and is then moved to a different physical location to be detected. Remote detection allows the separate optimization of the encoding and detection steps, permitting the independent choice of experimental conditions and excitation and detection methodologies. In the initial experimental demonstration of this technique, we show that taking dilute 129Xe from a porous sample placed inside a large encoding coil and concentrating it into a smaller detection coil can amplify NMR signal. In general, the study of NMR active molecules at low concentration that have low physical filling factor is facilitated by remote detection. In the second experimental demonstration, MRI information encoded in a very low-field magnet (4-7 mT) is transferred to a high-field magnet (4.2 T) to be detected under optimized conditions. Furthermore, remote detection allows the utilization of ultrasensitive optical or superconducting quantum interference device detection techniques, which broadens the horizon of NMR experimentation.

Moulé, Adam J.; Spence, Megan M.; Han, Song-I.; Seeley, Juliette A.; Pierce, Kimberly L.; Saxena, Sunil; Pines, Alexander

2003-08-01

2

Remotely detected high-field MRI of porous samples  

Science.gov (United States)

Remote detection of NMR is a novel technique in which an NMR-active sensor surveys an environment of interest and retains memory of that environment to be recovered at a later time in a different location. The NMR or MRI information about the sensor nucleus is encoded and stored as spin polarization at the first location and subsequently moved to a different physical location for optimized detection. A dedicated probe incorporating two separate radio frequency (RF)—circuits was built for this purpose. The encoding solenoid coil was large enough to fit around the bulky sample matrix, while the smaller detection solenoid coil had not only a higher quality factor, but also an enhanced filling factor since the coil volume comprised purely the sensor nuclei. We obtained two-dimensional (2D) void space images of two model porous samples with resolution less than 1.4 mm 2. The remotely reconstructed images demonstrate the ability to determine fine structure with image quality superior to their directly detected counterparts and show the great potential of NMR remote detection for imaging applications that suffer from low sensitivity due to low concentrations and filling factor.

Seeley, Juliette A.; Han, Song-I.; Pines, Alexander

2004-04-01

3

Auxiliary probe design adaptable to existing probes for remote detection NMR, MRI, and time-of-flight tracing  

Science.gov (United States)

A versatile, detection-only probe design is presented that can be adapted to any existing NMR or MRI probe with the purpose of making the remote detection concept generally applicable. Remote detection suggests freeing the NMR experiment from the confinement of using the same radio frequency (RF) coil and magnetic field for both information encoding and signal detection. Information is stored during the encoding step onto a fluid sensor medium whose magnetization is later measured in a different location. The choice of an RF probe and magnetic field for encoding can be made based solely on the size and characteristics of the sample and the desired information quality without considering detection sensitivity, as this aspect is dealt with by a separate detector. While early experiments required building probes that included two resonant circuits, one for encoding and one for detection, a modular approach with a detection-only probe as presented here can be used along with any existing NMR probe of choice for encoding. The design of two different detection-only probes is presented, one with a saddle coil for milliliter-sized detection volumes, and the other one with a microsolenoid coil for sub-microliter fluid quantities. As example applications, we present time-of-flight (TOF) tracing of hyperpolarized 129Xe spins in a gas mixture through coiled tubing using the microsolenoid coil detector and TOF flow imaging through a nested glass container where the gas flow changes its direction twice between inlet and outlet using the saddle coil detector.

Han, Songi; Granwehr, Josef; Garcia, Sandra; McDonnell, Erin E.; Pines, Alexander

2006-10-01

4

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

1981-01-01

5

MRI Technique May Help Detect Parkinson's Earlier  

Science.gov (United States)

... sharing features on this page, please enable JavaScript. MRI Technique May Help Detect Parkinson's Earlier Larger research ... 2014) Thursday, June 12, 2014 Related MedlinePlus Pages MRI Scans Parkinson's Disease THURSDAY, June 12, 2014 (HealthDay ...

6

Clinically Unrecognized Myocardial Scars Detected by MRI  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A high percentage of unrecognized myocardial infarctions (UMIs) seen at delayed-enhanced magnetic resonance imaging (DE-MRI) are not detected by ECG. DE-MRI-detected UMIs are independent predictors of cardiovascular events in patients with coronary artery disease. In an elderly population, subjects with DE-MRI-detected UMIs do not have increased Framingham risk score or increased prevalence of artery stenosis in whole-body MR angiography as patients with recognized myocardial infarctions (RMI...

Espregueira Themudo, Raquel

2012-01-01

7

Whole-body MRI (WB-MRI) versus axial skeleton MRI (AS-MRI) to detect and measure bone metastases in prostate cancer (PCa)  

Energy Technology Data Exchange (ETDEWEB)

To compare whole-body MRI (WB-MRI) and axial skeleton MRI (AS-MRI) in detecting and measuring bone metastases in patients with prostate cancer (PCa). WB-MRI and AS-MRI examinations were performed in 60 patients with PCa at high risk of metastases. Two radiologists separately categorised the AS-MRI and WB-MRI as negative or positive for metastases, and measured focal metastases using the ''Response evaluation criteria in solid tumours'' (RECIST) criteria transposed to bone. One radiologist reviewed all examinations 2 months later. Inter- and intraobserver agreements in establishing the presence/absence of metastases were calculated. Bland-Altman plots were used to assess measurement agreement between AS-MRI and WB-MRI. Strong to perfect inter- and intraobserver agreements were found between AS-MRI and WB-MRI in defining the presence/absence of bone metastases. There were no patients with isolated ''peripheral'' metastases at WB-MRI, missed at AS-MRI. There was no difference in lesion count between the two radiologists. AS-MRI and WB-MRI provided statistically equivalent RECIST values for one radiologist and slightly lower values at AS-MRI for the other. In our series of PCa patients, AS-MRI and WB-MRI were equivalent in determining the presence/absence of bone metastases and provided similar evaluation of the metastatic burden. (orig.)

Lecouvet, F.E.; Simon, M.; Berg, B.C.V.; Simoni, P. [Universite Catholique de Louvain, Cliniques Universitaires St Luc, Department of Radiology and Medical Imaging, Brussels (Belgium); Tombal, B. [Universite Catholique de Louvain, Cliniques Universitaires St Luc, Department of Urology, Brussels (Belgium); Jamart, J. [Universite Catholique de Louvain, Clinique Universitaire de Mont-Godinne, Center of Biostatistics and Medical Documentation, Yvoir (Belgium)

2010-12-15

8

Whole-body MRI (WB-MRI) versus axial skeleton MRI (AS-MRI) to detect and measure bone metastases in prostate cancer (PCa)  

International Nuclear Information System (INIS)

To compare whole-body MRI (WB-MRI) and axial skeleton MRI (AS-MRI) in detecting and measuring bone metastases in patients with prostate cancer (PCa). WB-MRI and AS-MRI examinations were performed in 60 patients with PCa at high risk of metastases. Two radiologists separately categorised the AS-MRI and WB-MRI as negative or positive for metastases, and measured focal metastases using the ''Response evaluation criteria in solid tumours'' (RECIST) criteria transposed to bone. One radiologist reviewed all examinations 2 months later. Inter- and intraobserver agreements in establishing the presence/absence of metastases were calculated. Bland-Altman plots were used to assess measurement agreement between AS-MRI and WB-MRI. Strong to perfect inter- and intraobserver agreements were found between AS-MRI and WB-MRI in defining the presence/absence of bone metastases. There were no patients with isolated ''peripheral'' metastases at WB-MRI, missed at AS-MRI. There was no difference in lesion count between the two radiologists. AS-MRI and WB-MRI provided statistically equivalent RECIST values for one radiologist and slightly lower values at AS-MRI for the other. In our series of PCa patients, AS-MRI and WB-MRI were equivalent in determining the presence/absence of bone metastases and provided similar evaluation of the metastatic burden. (orig.)

2010-12-01

9

Management of breast lesions detectable only on MRI.  

Science.gov (United States)

Breast MR imaging has become established as the most sensitive imaging method for diagnosing breast cancer. As a result of the increasing examination volume and improved image quality, the number of breast lesions detected only on MRI and requiring further clarification has risen in recent years. According to the S3-guideline "Diagnosis, Therapy, and Follow-Up of Breast Cancer" as revised in July 2012, institutions performing breast MRI should provide the option of an MRI-guided intervention for clarification. This review describes the indications, methods and results of MRI-guided interventions for the clarification of breast lesions only visible on MRI. Recent guidelines and study results are also addressed and alternative methods and pitfalls are presented. Key points: ? Up to 57 % of lesions originally visible only on MRI can be sonographically correlated and biopsied. ? MRI-guided intervention is necessary for the clarification of BI-RADS® 4 and 5 lesions detectable only on MRI ? MRI-guided vacuum-assisted breast biopsy should be preferentially used ? MRI-guided localization and surgical excision should be used if MRI-guided vacuum-assisted biopsy is not possible ? If BI-RADS® 4 and 5 findings visible only on MRI are not detectable on interventional MRI, a follow-up MRI should be performed within six months. PMID:23897532

Siegmann-Luz, K C; Bahrs, S D; Preibsch, H; Hattermann, V; Claussen, C D

2014-01-01

10

??????????????????MRI?????  

Directory of Open Access Journals (Sweden)

Full Text Available ???????????????????????????????????????????????????——????MRI??(??????????????????????????????????????????????????????????????????????????“?????”???????????????????????????????????????????????????????????????????????????

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2013-12-01

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.)

1995-10-24

12

Remote Detection of Explosives Using Trained Canines.  

Science.gov (United States)

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 remot...

J. C. Smith

1983-01-01

13

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

1983-03-28

14

Management of breast lesions detectable only on MRI  

International Nuclear Information System (INIS)

Breast MR imaging has become established as the most sensitive imaging method for diagnosing breast cancer. As a result of the increasing examination volume and improved image quality, the number of breast lesions detected only on MRI and requiring further clarification has risen in recent years. According to the S3-guideline 'Diagnosis, Therapy, and Follow-Up of Breast Cancer' as revised in July 2012, institutions performing breast MRI should provide the option of an MRI-guided intervention for clarification. This review describes the indications, methods and results of MRI-guided interventions for the clarification of breast lesions only visible on MRI. Recent guidelines and study results are also addressed and alternative methods and pitfalls are presented. (orig.)

2014-01-01

15

DETECTION OF TUMOR IN MRI USING VECTOR QUANTIZATION SEGMENTATION  

Directory of Open Access Journals (Sweden)

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.

Dr. H. B. Kekre

2010-08-01

16

Detecting breast microcalcifications with high-field MRI.  

Science.gov (United States)

The aim of this study was to detect microcalcifications in human whole breast specimens using high-field MRI. Four mastectomy specimens, obtained with approval of the institutional review board, were subjected to gradient-echo MRI acquisitions on a high-field MR scanner. The phase derivative was used to detect microcalcifications. The echo time and imaging resolution were varied to study the sensitivity of the proposed method. Computed tomography images of the mastectomy specimens and prior acquired mammography images were used to validate the results. A template matching algorithm was designed to detect microcalcifications automatically. The three spatial derivatives of the signal phase surrounding a field-perturbing object allowed three-dimensional localization, as well as the discrimination of diamagnetic field-perturbing objects, such as calcifications, and paramagnetic field-perturbing structures, e.g. blood. A longer echo time enabled smaller disturbances to be detected, but also resulted in shading as a result of other field-disturbing materials. A higher imaging resolution increased the detection sensitivity. Microcalcifications in a linear branching configuration that spanned over 8 mm in length were detected. After manual correction, the automatic detection tool identified up to 18 microcalcifications within the samples, which was in close agreement with the number of microcalcifications found on previously acquired in vivo mammography images. Microcalcifications can be detected by MRI in human whole breast specimens by the application of phase derivative imaging. PMID:24535752

de Leeuw, Hendrik; Stehouwer, Bertine L; Bakker, Chris J G; Klomp, Dennis W J; van Diest, Paul J; Luijten, Peter R; Seevinck, Peter R; van den Bosch, Maurice A A J; Viergever, Max A; Veldhuis, Wouter B

2014-05-01

17

Fast and direct detection of neuronal activation with diffusion MRI  

Energy Technology Data Exchange (ETDEWEB)

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 H{sub 2}O 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 bioph

Le Bihan, D. [Service Hospitalier Frederic Joliot (CEA/DSV/DRM), Lab. Anatomical and Functional Neuroimaging, 91 - Orsay (France); Urayama, S.; Aso, T.; Hanakawa, T.; Fukuyama, H. [Kyoto Univ. Graduate School of Medicine, Human Brain Research Center, Kyoto (Japan)

2006-07-01

18

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

2006-06-19

19

Semiparametric detection of significant activation for brain fMRI  

CERN Multimedia

Functional magnetic resonance imaging (fMRI) aims to locate activated regions in human brains when specific tasks are performed. The conventional tool for analyzing fMRI data applies some variant of the linear model, which is restrictive in modeling assumptions. To yield more accurate prediction of the time-course behavior of neuronal responses, the semiparametric inference for the underlying hemodynamic response function is developed to identify significantly activated voxels. Under mild regularity conditions, we demonstrate that a class of the proposed semiparametric test statistics, based on the local linear estimation technique, follow $\\chi^2$ distributions under null hypotheses for a number of useful hypotheses. Furthermore, the asymptotic power functions of the constructed tests are derived under the fixed and contiguous alternatives. Simulation evaluations and real fMRI data application suggest that the semiparametric inference procedure provides more efficient detection of activated brain areas than ...

Zhang, Chunming

2008-01-01

20

Reporting and management of breast lesions detected using MRI  

International Nuclear Information System (INIS)

Magnetic resonance imaging (MRI) is the most accurate technique for diagnosing and delineating the extent of both invasive and in-situ breast cancer and is increasingly being used as part of the preoperative work-up to assess the local extent of disease. It is proving invaluable in providing information that allows successful single-stage surgery. An inevitable consequence of the high sensitivity of MRI is that it will identify additional lesions that may or may not represent significant extra disease. This may complicate and delay the preoperative process. This paper outlines a strategy for managing MRI-detected lesions to optimize the benefits of breast MRI as a local staging tool while minimizing the false-positive diagnoses. It discusses the importance of good technique to reduce the number of indeterminate lesions. Methods to refine the patient pathway to minimize delays are discussed. The format of MRI reporting is discussed in detail as is the usefulness of discussion of cases at multidisciplinary meetings. Illustrative cases are used to clarify the points made.

2011-12-01

 
 
 
 
21

Reporting and management of breast lesions detected using MRI  

Energy Technology Data Exchange (ETDEWEB)

Magnetic resonance imaging (MRI) is the most accurate technique for diagnosing and delineating the extent of both invasive and in-situ breast cancer and is increasingly being used as part of the preoperative work-up to assess the local extent of disease. It is proving invaluable in providing information that allows successful single-stage surgery. An inevitable consequence of the high sensitivity of MRI is that it will identify additional lesions that may or may not represent significant extra disease. This may complicate and delay the preoperative process. This paper outlines a strategy for managing MRI-detected lesions to optimize the benefits of breast MRI as a local staging tool while minimizing the false-positive diagnoses. It discusses the importance of good technique to reduce the number of indeterminate lesions. Methods to refine the patient pathway to minimize delays are discussed. The format of MRI reporting is discussed in detail as is the usefulness of discussion of cases at multidisciplinary meetings. Illustrative cases are used to clarify the points made.

Dall, B.J.G., E-mail: Barbara.dall@leedsth.nhs.uk [Department of Radiology, Leeds General Infirmary, Leeds (United Kingdom); Vinnicombe, S. [Department of Radiology, St Bartholomew' s Hospital, London (United Kingdom); Gilbert, F.J. [Aberdeen Biomedical Imaging Centre, Aberdeen (United Kingdom)

2011-12-15

22

White matter injury detection in neonatal MRI  

Science.gov (United States)

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.

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

2013-02-01

23

MRI  

Medline Plus

Full Text Available Magnetic Resonance Imaging Scan (MRI) Introduction An MRI scan, or magnetic resonance imaging scan, is a test that provides very ... and risks of this procedure. Test A Magnetic Resonance Imaging scan, known as an MRI scan or ...

24

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Background 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...

Nakano Satoko; Ohtsuka Masahiko; Mibu Akemi; Karikomi Masato; Sakata Hitomi; Yamamoto Masahiro

2012-01-01

25

Novel Miniature Spectrometer For Remote Chemical Detection  

Energy Technology Data Exchange (ETDEWEB)

New chemical sensing technologies are critically important for addressing many of EM's priority needs as discussed in detail at http://emsp.em.doe.gov/needs. Many technology needs were addressed by this research. For example, improved detection strategies are needed for non-aqueous phase liquids (NAPL's), such as PCE (Cl2C=CCl2) and TCE (HClC=CCl2), which persist in the environment due their highly stable structures. By developing a miniature, ultra-sensitive, selective, and field-deployable detector for NAPL's, the approximate source location could be determined with minimal investigative expense. Contaminant plumes could also be characterized in detail. The miniature spectrometer developed under Project No.60231 could also permit accurate rate measurements in less time, either in the field or the laboratory, which are critically important in the development, testing, and ultimate utilization of models for describing contaminant transport. The technology could also be used for long-term groundwater monitoring or long-term stewardship in general. Many science needs are also addressed by the Project 60231, since the effort significantly advances the measurement science of chemical detection. Developed under Project No.60231, evanescent wave cavity ring-down spectroscopy (EW-CRDS) is a novel form of CRDS, which is an the emerging optical absorption technique. Several review articles on CRDS, which has been generally applied only to gas-phase diagnostics, have been published1-3. EW-CRDS4-10 forms the basis for a new class of chemical sensors that extends CRDS to other states of matter and leads to a miniaturized version of the concept. EW-CRDS uses miniature solid-state optical resonators that incorporate one or more total internal reflection (TIR) surfaces, which create evanescent waves. The evanescent waves emanate from the TIR surfaces, sampling the surrounding medium. The utility of evanescent waves in chemical analysis forms the basis for the field of attenuated total reflectance (ATR)11 spectroscopy. Many diagnostic problems can be solved by ATR methods that are intractable by ordinary methods, but ATR typically lacks sensitivity for ultra-trace chemical detection. In EWCRDS, the ring-down time of a resonator sensitively responds to chemical species present in the evanescent wave thereby combining the advantages of ATR with the sensitivity of CRDS. Furthermore, EW-CRDS forms the basis for a rugged miniature chemical sensor for which the laser source and photodetector can be located remotely by using optical fiber. Work on EW-CRDS began at NIST with the NRC postdoctoral associateship of the current Principal Investigator during fiscal 1996-1997. Since completion of the NRC associateship, work on EW-CRDS has been majority funded through Project 60231, with some additional funding from the Advanced Technology Program (35K/year in 2000).

Pipino, Andrew C.R.

2000-09-14

26

Research on Remote Network Bidirectional Detect and Control Model  

Directory of Open Access Journals (Sweden)

Full Text Available Remote network bidirectional detect and control technologies are the key factors to solve local network allopatry expansibility and management. With studying gateway integration technology, bidirectional VPN technology, identity authentication technology and dynamic host management technology can be integrated into gateway. Thus, bidirectional connect and control among allopatry local networks based on Internet can be solved. Whole area expansibility of local network is realized. With experiment, the model is proved to finish remote bidirectional interconnection of local network automatically and to obtain allopatry local users authority. The equipment detecting and controlling in remote local networks are realized.  

Hongyao Ju

2013-09-01

27

Novel Miniature Spectrometer for Remote Chemical Detection  

Energy Technology Data Exchange (ETDEWEB)

A entirely new class of chemical sensors is being developed that will enable qualitative and quantitative remote, real-time, optical diagnostics of chemical species in hazardous gas, liquid, and semi-solid phases through a completely novel implementation of cavity ring-down spectroscopy. The sensor design uses a tiny, solid block (< 1cm3) of ultra-high purity optical material that is fabricated into a regular, planar polygon with a single convex facet to form a total-internal-reflection (TIR) ring minicavity. The lifetime of a light pulse that is injected into the cavity is extremely sensitive to chemical species in contact with the cavity. By using optical fiber to remotely locate the light source and detector, this new technology will permit high-sensitivity, remote chemical sensing with a rugged, cost-effective device.

Pipino, Andrew C.R.

1999-06-01

28

Combined HRCT and MRI in the Detection of CSF Rhinorrhea  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Cerebrospinal fluid (CSF) rhinorrhea is a potentially dangerous problem. Accurate preoperative localization of the site of leakage is mandatory. The standard diagnostic technique is computed tomography (CT) cisternography. Because of its related risks, however, various alternatives have been suggested. High-resolution CT (HRCT) provides good bony details, but fluid is poorly detected. In contrast, T2-weighted magnetic resonance imaging (MRI) shows CSF as a bright signal, but spatial resolutio...

Mostafa, Badr Eldin; Khafagi, Ahmed

2004-01-01

29

Ex vivo MRI evaluation of breast tumors: a novel tool for verifying resection of nonpalpable only MRI detected lesions.  

Science.gov (United States)

A fundamental question in surgery of only magnetic resonance imaging (MRI)-detected breast lesions is to ensure their removal when they are not palpable by clinical examination and surgical exploration. This is especially relevant in the case of small tumors, carcinoma in situ or lobular carcinoma. Thirty-nine patients were enrolled in the study, 21 patients with breast lesions detected by both conventional imaging and breast MRI (bMRI) and 18 patients with bMRI findings only. Preoperative bMRI allowed staging the disease and localizing the lesion. In the operating theater, contrast medium was injected 1 minute before skin incision. After removal, surgical specimens were submitted to ex vivo MRI, performed using a dedicated surface coil and Spair inversion recovery sequences for suppression of fat signal intensity. All MRI enhancing lesions were completely included within the surgical specimen and visualized by ex vivo MRI. In the first 21 patients, bMRI was able to visualize branching margins or satellite nodules around the core lesion, and allowed for better staging of the surrounding in situ carcinoma; in the last 18 patients, eight of whom were breast cancer type 1 susceptibility protein (BRCA) mutation carriers, bMRI identified 12 malignant tumors, otherwise undetectable, that were all visualized by ex vivo MRI. This is the first description of a procedure that re-enhances breast lesions within a surgical specimen, demonstrating the surgical removal of nonpalpable breast lesions diagnosed only with bMRI. This new strategy reproduces the morphology and the entire extension of the primary lesion on the specimen, with potentially better local surgical control, reducing additional unplanned surgery. PMID:24102850

Agresti, Roberto; Trecate, Giovanna; Ferraris, Cristina; Valeri, Barbara; Maugeri, Ilaria; Pellitteri, Cristina; Martelli, Gabriele; Migliavacca, Silvana; Carcangiu, Maria Luisa; Bohm, Silvia; Maffioli, Lorenzo; Vergnaghi, Daniele; Panizza, Pietro

2013-01-01

30

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.)

2002-08-01

31

MRI  

Medline Plus

Full Text Available ... cochlear implants should CHECK with the doctor who implanted the devices about whether they can undergo an MRI. Patients who have had a stent placed within 6 weeks of the MRI should check with their doctor before having an MRI. Other implanted metallic material, such as a hip replacement or ...

32

MRI  

Medline Plus

Full Text Available Magnetic Resonance Imaging Scan (MRI) Introduction An MRI scan, or magnetic resonance imaging scan, is a test that provides very ... benefits and risks of this procedure. Test A Magnetic Resonance Imaging scan, known as an MRI scan or ...

33

[A mobile sensor for remote detection of natural gas leakage].  

Science.gov (United States)

The detection of natural gas pipeline leak becomes a significant issue for body security, environmental protection and security of state property. However, the leak detection is difficult, because of the pipeline's covering many areas, operating conditions and complicated environment. A mobile sensor for remote detection of natural gas leakage based on scanning wavelength differential absorption spectroscopy (SWDAS) is introduced. The improved soft threshold wavelet denoising was proposed by analyzing the characteristics of reflection spectrum. And the results showed that the signal to noise ratio (SNR) was increased three times. When light intensity is 530 nA, the minimum remote sensitivity will be 80 ppm x m. A widely used SWDAS can make quantitative remote sensing of natural gas leak and locate the leak source precisely in a faster, safer and more intelligent way. PMID:22512213

Zhang, Shuai; Liu, Wen-qing; Zhang, Yu-jun; Kan, Rui-feng; Ruan, Jun; Wang, Li-ming; Yu, Dian-qiang; Dong, Jin-ting; Han, Xiao-lei; Cui, Yi-ben; Liu, Jian-guo

2012-02-01

34

Modelling and interpretation of gas detection using remote laser pointers.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We have developed a quantitative model of the performance of laser pointer style gas leak detectors, which are based on remote detection of backscattered radiation. The model incorporates instrumental noise limits, the reflectivity of the target background surface and a mathematical description of gas leak dispersion in constant wind speed and turbulence conditions. We have investigated optimum instrument performance and limits of detection in simulated leak detection situations. We predict t...

Hodgkinson, Jane; Well, Ben; Padgett, Miles; Pride, Russ D.

2006-01-01

35

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

Energy Technology Data Exchange (ETDEWEB)

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 < 0.01) in lesion size measurement compared to CT. Unenhanced, T1-weighted VIBE correctly classified 94% of thoracic malignancies into T-stages. Contrast-enhanced, T1-weighted VIBE performed best in identifying 36% of lung nodules, 40% were detected combining unenhanced and contrast-enhanced T1-weighted VIBE. Detection rate increased to 65% for the combined sequences regarding lesions =5 mm. Lesion size measurement by all MR sequences strongly correlated with CT (r = 0.96-0.97; P = 0.01). Conclusion. MRI is as accurate as CT in detection and size measurement of primary thoracic malignancies >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

Heye, Tobias; Kauczor, Hans-Ulrich; Hosch, Waldemar (Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg (Germany)), Email: tobias.heye@med.uni-heidelberg.de; Ley, Sebastian (Division of Cardiothoracic Imaging University Health Network, Mount Sinai Hospital and Women' s College Hospital University of Toronto (Canada)); Heussel, Claus Peter (Department of Diagnostic and Interventional Radiology, Thoraxklinik, University of Heidelberg (Germany)); Dienemann, Hendrik (Department of Thoracic Surgery, Thoraxklinik, University of Heidelberg (Germany)); Libicher, Martin (Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg (Germany); Department of Diagnostic and Interventional Radiology, Diakonie Klinikum, Schwaebisch Hall (Germany))

2012-03-15

36

Motion Detection in Diffusion MRI via Online ODF Estimation.  

Science.gov (United States)

The acquisition of high angular resolution diffusion MRI is particularly long and subject motion can become an issue. The orientation distribution function (ODF) can be reconstructed online incrementally from diffusion-weighted MRI with a Kalman filtering framework. This online reconstruction provides real-time feedback throughout the acquisition process. In this article, the Kalman filter is first adapted to the reconstruction of the ODF in constant solid angle. Then, a method called STAR (STatistical Analysis of Residuals) is presented and applied to the online detection of motion in high angular resolution diffusion images. Compared to existing techniques, this method is image based and is built on top of a Kalman filter. Therefore, it introduces no additional scan time and does not require additional hardware. The performance of STAR is tested on simulated and real data and compared to the classical generalized likelihood ratio test. Successful detection of small motion is reported (rotation under 2°) with no delay and robustness to noise. PMID:23509445

Caruyer, Emmanuel; Aganj, Iman; Lenglet, Christophe; Sapiro, Guillermo; Deriche, Rachid

2013-01-01

37

Hemorrhage detection in MRI brain images using images features  

Science.gov (United States)

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.

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

2013-11-01

38

Diagnostic value of a breast MRI score for the prediction of malignancy of breast lesions detected solely with MRI  

International Nuclear Information System (INIS)

Purpose: to determine whether lesion scoring allows valid BI-RADS registered classification and prediction of malignancy of breast lesions detectable solely with MRI. Materials and methods: retrospective analysis of 86 patients who underwent MRI-guided localization and excisional biopsy of 100 breast lesions detectable only with MRI. Breast MRI was performed at 1.5 Tesla by means of a T1w dynamic GE sequence. The positive predictive value (PPV) for malignancy was calculated for each score criterion separately, for the total score, and for corresponding BI-RADS registered classes. The PPV was correlated with histology. Results: 31% (31/100) of breast lesions detectable only with MRI were malignant. Of the single score criteria only the lesion morphology criterion was significantly correlated with malignancy. The malignancy rate according to the breast MRI score was 0% for score 3, 18.2% for score 4, 32.1% for score 5 and each 50% for lesions of score 6 and 7. After translation into BI-RADS registered the malignancy rates were 0% for BI-RADS registered 3, 24.6% for BI-RADS registered 4 and 48.5% for BI-RADS registered 5 lesions. The thus defined BI-RADS registered classes were significantly correlated with malignancy. (orig.)

2009-06-01

39

Two-Dimensional Change Detection Methods Remote Sensing Applications  

CERN Document Server

Change detection using remotely sensed images has many applications, such as urban monitoring, land-cover change analysis, and disaster management. This work investigates two-dimensional change detection methods. The existing methods in the literature are grouped into four categories: pixel-based, transformation-based, texture analysis-based, and structure-based. In addition to testing existing methods, four new change detection methods are introduced: fuzzy logic-based, shadow detection-based, local feature-based, and bipartite graph matching-based. The latter two methods form the basis for a

Ilsever, Murat

2012-01-01

40

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

2005-06-01

 
 
 
 
41

SQUID-Detected In Vivo MRI at Microtesla Magnetic Fields  

Energy Technology Data Exchange (ETDEWEB)

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.

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

2005-06-01

42

?????????????????? Detection Automation of the Electric Car Remote Monitoring System Terminal  

Directory of Open Access Journals (Sweden)

Full Text Available ???????????????????????????????????????????????????????(??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? At this stage, with the great support of pure electric vehicles from the State, pure electric vehicle industry line has been very clear. Along with the development of electric car production, electric vehicle remote monitoring system (safety equipment will be mass produced. However, electric cars remote monitoring system terminal in use, maintenance of the production process and test cost is difficult to control, it has a direct impact on the quality of the terminal and the precision of data collection. This paper mainly introduces the electric vehicle remote monitoring system terminal in the production process of detection automation. By using computer software and terminal communication terminal, access to important information and guide the operators fast processing, thereby improving the production efficiency and product quality.

???

2013-04-01

43

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

Science.gov (United States)

Background 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. Methods 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. Results 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. Conclusions 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.

2012-01-01

44

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

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background 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. Methods 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. Results 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. Conclusions 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.

Nakano Satoko

2012-06-01

45

MRI of the brain and cervical spine: first choice in the detection of abnormalities  

International Nuclear Information System (INIS)

The preliminary results are presented of a comparative study between MRI and CT in 150 patients from the University Hospital Utrecht. The purpose is through a prospective study to make more definitive assessments about the role and the value of MRI in the region of the brain and cervical spine. If compared with CT, no abnormalities were missed with MRI in 150 cases; MRI detected more lesions than CT, and often more information was provided by MRI. Spin-echo pulse sequence with long multiple echoes and short repetition time proved to be a sensitive detection method with sufficient tissue characterization for diagnosis. In the opinion of the authors, MRI should be the first step in detecting abnormalities of the brain and cervical spine. (Auth.)

1985-04-26

46

US correlation for MRI-detected breast lesions in women with familial risk of breast cancer  

International Nuclear Information System (INIS)

AIM: To examine the value of US correlation for MRI-detected breast lesions in women with familial risk of breast cancer. METHODS: From an initial dataset of 245 women with positive family history who had breast cancer surveillance involving mammography or MRI between November 1994 and February 2001, 179 subjects with follow-up data were selected. A total of 43 women with 48 MRI-detected lesions underwent further assessment with US. Histopathological correlation was available from 38 breast biopsies performed for 33 women. RESULTS: Sonographic correlates were identified in 32 (66.7%) of the 48 MRI-detected lesions, with cancer present in 11 (34.4%) of these. This compares with 1 (6.3%) cancer found in the 16 lesions without sonographic correlates. Of the 12 malignant lesions, 11 (91.7%) had sonographic correlates whereas 21 (58.3%) of the 36 benign lesions had sonographic correlates. In all 74% of breast biopsies were performed under US guidance compared with 8% under MRI guidance. The proportion of MRI- and US-correlated benign and malignant lesions undergoing US-guided biopsy were 85.7% and 90.9%, respectively. CONCLUSION: The probability of cancer was significantly higher in MRI-detected breast lesions with sonographic correlates compared with those without such correlation. The advantage of convenient biopsy under US guidance as opposed to MRI guidance highlights the value of sonographic assessment of MRI-detected breast lesions

2005-07-01

47

Cystic apocrine hyperplasia is the most common finding in MRI detected breast lesions.  

Science.gov (United States)

MRI of the breast is an increasingly employed modality for breast imaging due to its relatively high sensitivity for the detection of breast carcinoma. Cumulative data indicate that MRI of the breast has relatively higher sensitivity, but lower specificity than mammography. However, data regarding the diagnostic yield for particular types of breast lesions detected via breast MRI remain scant. Over a 3.5-year period, we evaluated histological findings of 192 needle core biopsies of MRI detected breast lesions. In this series, the positive predictive value of MRI detected lesions for breast carcinoma was 20%. Invasive carcinoma was diagnosed in 16/192 (8%) and in situ carcinoma in 22/192 (11%). The most commonly detected histological finding was cystic apocrine hyperplasia (19%), a benign entity. PMID:24151291

Ginter, Paula S; Winant, Abbey J; Hoda, Syed A

2014-02-01

48

Preoperative detection of the eloquent areas of the brain using functional MRI  

International Nuclear Information System (INIS)

Forty-eight patients with 50 supratentorial gliomas were studied by functional MRI for motor and language areas before operation. Reliability of fMRI was evaluated comparing with Wada test and the brain mapping and/or cortical stimulation during awake surgery. For detecting motor area, activation of fMRI presented a reliable correlation with brain mapping when patients could follow tasks. Combined examination of fMRI with Wada test is useful to detect the speech area of the brain. (author)

2005-08-01

49

MRI  

Medline Plus

Full Text Available ... the advice of a doctor or a healthcare professional for your specific condition. ... out of the MRI room. This will protect your watch, beepers, credit cards, and other magnet- ...

50

MRI  

Medline Plus

Full Text Available ... MRI technology is relatively recent, the very long-term effects are not known. There are no reasons ... suspect any harmful effect but, again, these long-term effects are NOT known. Because of the possible ...

51

MRI  

Medline Plus

Full Text Available ... clip is compatible with magnets. Patients with metallic fragments in or near the eyes or blood vessels ... MRI. If you suspect you may have metallic fragments anywhere in your body, let the technologists know. ...

52

MRI  

Medline Plus

Full Text Available ... the MRI. The patients at highest risk for metal fragments are welders and people injured by shrapnel or bullets. Patients with epidural electrodes and with cochlear implants should CHECK with the doctor who implanted the ...

53

MRI  

Medline Plus

Full Text Available ... cards, and other magnet-sensitive devices from the effects of the MRI machine. You will be placed ... technology is relatively recent, the very long-term effects are not known. There are no reasons to ...

54

MRI  

Medline Plus

Full Text Available ... allergies that you may have. Because of the large magnet, many patients with cardiac pacemakers or artificial ... lie very still. Because an MRI uses a large magnet instead of x-rays, it is safer ...

55

MRI  

Medline Plus

Full Text Available ... various diseases such as brain tumors or torn ligaments. If your doctor recommends an MRI, the decision ... material, such as a hip replacement or a knee replacement, may not be a problem. It is ...

56

Research on Remote Network Bidirectional Detect and Control Model  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Remote network bidirectional detect and control technologies are the key factors to solve local network allopatry expansibility and management. With studying gateway integration technology, bidirectional VPN technology, identity authentication technology and dynamic host management technology can be integrated into gateway. Thus, bidirectional connect and control among allopatry local networks based on Internet can be solved. Whole area expansibility of local network is realized. With experim...

Hongyao Ju; Xin Wang; Fei Luo

2013-01-01

57

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)

1994-11-01

58

MRI breast screening in high-risk women: cancer detection and survival analysis.  

Science.gov (United States)

Women with a genetic predisposition to breast cancer tend to develop the disease at a younger age with denser breasts making mammography screening less effective. The introduction of magnetic resonance imaging (MRI) for familial breast cancer screening programs in recent years was intended to improve outcomes in these women. We aimed to assess whether introduction of MRI surveillance improves 5- and 10-year survival of high-risk women and determine the accuracy of MRI breast cancer detection compared with mammography-only or no enhanced surveillance and compare size and pathology of cancers detected in women screened with MRI + mammography and mammography only. We used data from two prospective studies where asymptomatic women with a very high breast cancer risk were screened by either mammography alone or with MRI also compared with BRCA1/2 carriers with no intensive surveillance. 63 cancers were detected in women receiving MRI + mammography and 76 in women receiving mammography only. Sensitivity of MRI + mammography was 93 % with 63 % specificity. Fewer cancers detected on MRI were lymph node positive compared to mammography/no additional screening. There were no differences in 10-year survival between the MRI + mammography and mammography-only groups, but survival was significantly higher in the MRI-screened group (95.3 %) compared to no intensive screening (73.7 %; p = 0.002). There were no deaths among the 21 BRCA2 carriers receiving MRI. There appears to be benefit from screening with MRI, particularly in BRCA2 carriers. Extended follow-up of larger numbers of high-risk women is required to assess long-term survival. PMID:24687378

Gareth, Evans D; Nisha, Kesavan; Yit, Lim; Soujanye, Gadde; Emma, Hurley; Massat, Nathalie J; Maxwell, Anthony J; Sarah, Ingham; Rosalind, Eeles; Leach, Martin O; Anthony, Howell; Stephen, Duffy

2014-06-01

59

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

Energy Technology Data Exchange (ETDEWEB)

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.)

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

60

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.)

2006-07-01

 
 
 
 
61

MRI  

Science.gov (United States)

... provider before the test if you have kidney problems. The strong magnetic fields created during an MRI can cause heart pacemakers and other implants not to work as well. The magnets can also cause a piece of metal inside your body to move or shift.

62

Active remote detection of radioactivity based on electromagnetic signatures  

Science.gov (United States)

This paper presents a new concept for the remote detection of radioactive materials. The concept is based on the detection of electromagnetic signatures in the vicinity of radioactive material and can enable stand-off detection at distances greater than 100 m. Radioactive materials emit gamma rays, which ionize the surrounding air. The ionized electrons rapidly attach to oxygen molecules forming O2- ions. The density of O2- around radioactive material can be several orders of magnitude greater than background levels. The elevated population of O2- extends several meters around the radioactive material. Electrons are easily photo-detached from O2- ions by laser radiation. The photo-detached electrons, in the presence of laser radiation, initiate avalanche ionization which results in a rapid increase in electron density. The rise in electron density induces a frequency modulation on a probe beam, which becomes a direct spectral signature for the presence of radioactive material.

Sprangle, P.; Hafizi, B.; Milchberg, H.; Nusinovich, G.; Zigler, A.

2014-01-01

63

Active remote detection of radioactivity based on electromagnetic signatures  

International Nuclear Information System (INIS)

This paper presents a new concept for the remote detection of radioactive materials. The concept is based on the detection of electromagnetic signatures in the vicinity of radioactive material and can enable stand-off detection at distances greater than 100?m. Radioactive materials emit gamma rays, which ionize the surrounding air. The ionized electrons rapidly attach to oxygen molecules forming O2? ions. The density of O2? around radioactive material can be several orders of magnitude greater than background levels. The elevated population of O2? extends several meters around the radioactive material. Electrons are easily photo-detached from O2? ions by laser radiation. The photo-detached electrons, in the presence of laser radiation, initiate avalanche ionization which results in a rapid increase in electron density. The rise in electron density induces a frequency modulation on a probe beam, which becomes a direct spectral signature for the presence of radioactive material

2014-01-01

64

Detection of Aerosol type using satellite remote sensing  

Science.gov (United States)

The effects of aerosols on the Earth s climate have been studied extensively by using observations and model studies As the effects of aerosol on the climate are different from one type to the other aerosol type detection from satellite remote sensing is very important There have been several methods to classify aerosol from satellite remote sensing e g Higurashi and Nakajima 2003 Jeong and Li 2005 etc This study shows temporal and spatial distribution of four major aerosol types dust carbonaceous seasalt and sulfate retrieved by MODIS-OMI algorithm and 4-channel algorithm from Moderate Resolution Imaging Spectroradiometer MODIS and Ozone Monitoring Instrument OMI data over the South-East Asia region Retrieved results show that there exist complex types of aerosol over the South-East Asia In general two different aerosol classification algorithm make reasonably consistent results for most of the aerosol types Dust type aerosol usually occurred mixed with carbonaceous type aerosol It implies that the dust type aerosol is loaded and transported with polluted air mass The evidence of long distance transport of polluted air mass in the continent is also captured that is over the remote ocean area Validation of the results with ground-based chemistry measurements or chemical transfer model CTM and separate estimation of the different aerosol optical depths are desirable

Kim, J.; Lee, J. H.; Yoon, J. M.; Cho, H. K.

65

Comparison of bone scintigraphy and MRI imaging in detecting vertebral metastatic tumors  

International Nuclear Information System (INIS)

Objective: To compare the diagnostic value of bone scintigraphy and MRI in detecting vertebral metastastic tumors. Method:A retrospective comparison was made between 99mTc-MDP bone scintigraphy and corresponding spine MRI in 76 patients who had complementary studies within 1 month. There were 42 male and 34 female patients diagnosed with cancer prior to these studies. Cancer diagnoses included 29 lung, 15 breast, 5 liver, 5 esophagus, 4 rectum, 2 bladder, 2 thymus, 1 nasopharynx, 1 endometrium, 3 cervix uterus, 1 mucinous cystadenocarcinoma, 2 stomach,1syringocarcinoma. Ninteen patients complained backpain. Forty-two patients had bone scintigraphies done before MRI, 30 patients had MRI done after bone scintigraphy, only 4 patients had both studies on the same day. The spinal and pelvic bones which were in the scan field of MRI were observed to compare the demonstration of the lesions using bone scintigraphy and MRI. Bone scintigraphy were obtained using GE STARCAM 4000 SPECT, equipped with a parallel-hole, low-energy, high resolution collimator, 2 to 3 hrs after intravenous injection of 25 mCi (925MBq) of 99mTc-MDP, in anterior and post position after urinating.. MR studies were performed with a GE 1.5 tesla signal scanner. All patients were studied with T1-weihgted and T2-weighted spin echo sequences obtained in the sagittal plane, T1-weighted in trasversal plane ordinarily, and contrast enhancement or in coronal plane if necessary. The spinal and pelvic bones which were in the scan field of MRI were observed to compare the demonstration of the lesions using bone scintigraphy and MRI. Bone scintigraphy regions were read positive when its uptake of tracer was increased or decreased obviously compared to adjacent or contralateral structures. The criteria for the MRI diagnosis of metastases were the presence fof a well defined focus of low signals on the T1-weighted images , high and low mixed or high signal intensity on T2-weighted spin echo sequences.The comparison of the paired data were determined with a chi-square test and #P­# 0.05 was considered significant Results: Among the 76 patients, bone scintigraphy and MRI almost detected the same vertebral metastatic cases and metastatic foci .The rate of positive cases was 83.95% (68/81) and 75.30% (61/81). The rate of positive metastatic foci was 31.15% (167/536) and 29.10% (156/536). Two methods revealed that the lesions most commonly located in thoracic vertebrae, MRI detected more metastatic foci than bone scintigraphy in the site 83%(83/237) and 64% (64/237). There was no difference between bone scintigraphy and MRI in detecting metastatic foci in lumbar vertebrae. Bone scintigraphy was better than MRI in detecting cervical spine and sacrum (15/63 and 6/63 , 23/78 and 10/78 , respectively ) . MRI was better than bone scintigraphy in detecting multiple metastatic foci (143/237 and 116/237, respectively ). There were fasle positive of single focus both in bone scintigraphy (3/16) and MRI (2/11), and fasle negative foci in rapidly progressive condition in bone scintigraphy. Bone scintigraphy revealed 111 foci outside spine in 42 patients. Conclusion: The sensitivity of bone scintigraphy and MRI in detecting vertebral metastatic lesions were similar. MRI is more efficient in detecting thoracic and multiple vertebral metastases. However bone scintigraphy is more efficient in detecting vertebral metastases in cervical spine and sacrum than MRI. Considering its cost and the convenience of performing a whole-body survey for metastasis, bone scintigraphy remains the study of choice for initial evaluation of patients with cancer. MRI is a further complementary technique when bone scintigraphy findings are inadequate for answering clinical questions

2002-09-01

66

Motion Detection in Diffusion MRI via Online ODF Estimation  

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The acquisition of high angular resolution diffusion MRI is particularly long and subject motion can become an issue. The orientation distribution function (ODF) can be reconstructed online incrementally from diffusion-weighted MRI with a Kalman filtering framework. This online reconstruction provides real-time feedback throughout the acquisition process. In this article, the Kalman filter is first adapted to the reconstruction of the ODF in constant solid angle. Then, a method called STAR (S...

2013-01-01

67

Motion Detection in Diffusion MRI via Online ODF Estimation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The acquisition of high angular resolution diffusion MRI is particularly long and subject motion can become an issue. The orientation distribution function (ODF) can be reconstructed online incrementally from diffusion-weighted MRI with a Kalman filtering framework. This online reconstruction provides real-time feedback throughout the acquisition process. In this article, the Kalman filter is first adapted to the reconstruction of the ODF in constant solid angle. Then, a method called STAR (S...

2012-01-01

68

MRI Detects Cancers in the Opposite Breast of Women Newly Diagnosed with Breast Cancer  

Science.gov (United States)

Magnetic Resonance Imaging (MRI) scans of women who were diagnosed with cancer in one breast detected over 90 percent of cancers in the other breast that were missed by mammography and clinical breast exam at initial diagnosis, according to a new study. Given the established rates of mammography and clinical breast exams for detecting cancer in the opposite, or contralateral breast, adding an MRI scan to the diagnostic evaluation effectively doubled the number of cancers immediately found in these women.

69

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.

2011-08-01

70

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

Science.gov (United States)

Background 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.

Dubrow, Samuel A; Streit, Jonathan J; Shishani, Yousef; Robbin, Mark R; Gobezie, Reuben

2014-01-01

71

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

1994-11-07

72

A remote canister-positioning and glass level detection system  

International Nuclear Information System (INIS)

This paper presents a remote, contactless microprocessor-based control system has been designed, developed, tested, and used that accurately positions glass-receiving canisters beneath a radioactive liquid-fed ceramic melter and monitors the height and extent of cross-sectional glass fill. Both tasks are accomplished using in-cell gamma-ray sources and out-of-cell detection, analysis and data interpretation equipment. The system aligns the canister axis with the melter overflow section to within ? 3 mm. The canister glass level at 11 fixed elevations is measured to within ± 5 mm, while as little as 5 mm of linear cross-sectional voiding (or equivalent glass thickness) can be detected in 30-cm-diam canisters

1990-01-01

73

A remote canister-positioning and glass level detection system  

Energy Technology Data Exchange (ETDEWEB)

This paper presents a remote, contactless microprocessor-based control system has been designed, developed, tested, and used that accurately positions glass-receiving canisters beneath a radioactive liquid-fed ceramic melter and monitors the height and extent of cross-sectional glass fill. Both tasks are accomplished using in-cell gamma-ray sources and out-of-cell detection, analysis and data interpretation equipment. The system aligns the canister axis with the melter overflow section to within {approximately} 3 mm. The canister glass level at 11 fixed elevations is measured to within {+-} 5 mm, while as little as 5 mm of linear cross-sectional voiding (or equivalent glass thickness) can be detected in 30-cm-diam canisters.

Goles, R.W.; Hof, P.J.; Dierks, R.D.; Holton, L.K. Jr. (Pacific Northwest Lab., Richland, WA (USA))

1990-02-01

74

Can breast MRI computer-aided detection (CAD) improve radiologist accuracy for lesions detected at MRI screening and recommended for biopsy in a high-risk population?  

Energy Technology Data Exchange (ETDEWEB)

Aim: To evaluate the sensitivity and specificity of magnetic resonance imaging (MRI) computer-aided detection (CAD) for breast MRI screen-detected lesions recommended for biopsy in a high-risk population. Material and methods: Fifty-six consecutive Breast Imaging Reporting and Data System (BI-RADS) 3-5 lesions with histopathological correlation [nine invasive cancers, 13 ductal carcinoma in situ (DCIS) and 34 benign] were retrospectively evaluated using a breast MRI CAD prototype (CAD-Gaea). CAD evaluation was performed separately and in consensus by two radiologists specializing in breast imaging, blinded to the histopathology. Thresholds of 50, 80, and 100% and delayed enhancement were independently assessed with CAD. Lesions were rated as malignant or benign according to threshold and delayed enhancement only and in combination. Sensitivities, specificities, and negative predictive values (NPV) were determined for CAD assessments versus pathology. Initial MRI BI-RADS interpretation without CAD versus CAD assessments were compared using paired binary diagnostic tests. Results: Threshold levels for lesion enhancement were: 50% to include all malignant (and all benign) lesions; and 100% for all invasive cancer and high-grade DCIS. Combined use of threshold and enhancement patterns for CAD assessment was best (73% sensitivity, 56% specificity and 76% NPV for all cancer). Sensitivities and NPV were better for invasive cancer (100%/100%) than for all malignancies (54%/76%). Radiologists' MRI interpretation was more sensitive than CAD (p = 0.05), but less specific (p = 0.001) for cancer detection. Conclusion: The breast MRI CAD system used could not improve the radiologists' accuracy for distinguishing all malignant from benign lesions, due to the poor sensitivity for DCIS detection.

Arazi-Kleinman, T., E-mail: t_arazikleinman@yahoo.co [Department of Medical Imaging, Sunnybrook Health Sciences Centre, University of Toronto, Toronto (Canada); Department of Medical Imaging Tel Aviv Sourasky Medical Centre, Sackler School of Medicine Tel Aviv University, Tel Aviv (Israel); Causer, P.A.; Jong, R.A. [Department of Medical Imaging, Sunnybrook Health Sciences Centre, University of Toronto, Toronto (Canada); Hill, K.; Warner, E. [Division of Medical Oncology, Department of Medicine, Sunnybrook Health Sciences Centre, University of Toronto, Toronto (Canada)

2009-12-15

75

MRI in the evaluation of spina bifida patients in the remote period after meningomyelocele repair  

International Nuclear Information System (INIS)

MRI was performed on 22 patients ranging in age from 3 months to 16 years who had closure of their meningomyelocele shortly after birth. These patients had developed new clinical findings suggestive of spinal cord dysfunction. MRI showed low placement of the spinal cord in all 22. Six patients had lipomas, five had diastematomyelia and six had hydromyelia. Four patients had an obviously dysplastic terminal cord. (orig.)

1989-01-01

76

MRI in the evaluation of spina bifida patients in the remote period after meningomyelocele repair  

Energy Technology Data Exchange (ETDEWEB)

MRI was performed on 22 patients ranging in age from 3 months to 16 years who had closure of their meningomyelocele shortly after birth. These patients had developed new clinical findings suggestive of spinal cord dysfunction. MRI showed low placement of the spinal cord in all 22. Six patients had lipomas, five had diastematomyelia and six had hydromyelia. Four patients had an obviously dysplastic terminal cord. (orig.).

Williamson, M.R.; Glasier, C.M.; Chadduck, W.M.; Angtuaco, E.J.C.; Binet, E.F.

1989-07-01

77

Detection and grading of dAVF: prospects and limitations of 3T MRI  

Energy Technology Data Exchange (ETDEWEB)

DSA is currently the criterion standard for the assessment of dural arteriovenous fistulas (dAVF). Recently, evolving MRA techniques have emerged as a non-invasive alternative. The aim of this study is to assess the value of 3 T MRI in detecting and describing dAVF and to determine whether MRI can replace DSA as diagnostic procedure. A total of 19 patients with dAVF and 19 without dAVF underwent the same MRI protocol, including 3D time-of-flight MRA and time-resolved contrast-enhanced MRA. The images were evaluated retrospectively by three independent readers with different levels of experience blinded to clinical information. The readers assessed the presence, the site, the venous drainage and the feeders of dAVF. Sensitivity, specificity, accuracy, intertechnique and interobserver agreements were calculated. DAVF can be detected with high sensitivity, specificity and accuracy by experienced and also by less experienced readers. However, MRI has limitations when used for grading and evaluation of the angioarchitecture of the dAVF. Different experience, the limited resolution of MRI and its inability to selectively display arteries were the reasons for these limitations. With MRI dAVF can be detected reliably. Nevertheless, at present MRI can not fully replace DSA, especially for treatment planning. (orig.)

Bink, Andrea; Berkefeld, Joachim; Wagner, Marlies; You, Se-Jong; Mesnil de Rochemont, Richard du [Johann Wolfgang Goethe University, Department of Neuroradiology, Frankfurt am Main (Germany); Ackermann, Hanns [Johann Wolfgang Goethe University, Institute of Biostatistics and Mathematical Modeling, Frankfurt/Main (Germany); Lorenz, Matthias W. [Johann Wolfgang Goethe University, Department of Neurology, Frankfurt/Main (Germany); Senft, Christian [Johann Wolfgang Goethe University, Department of Neurosurgery, Frankfurt/Main (Germany)

2012-02-15

78

Detection and grading of dAVF: prospects and limitations of 3T MRI  

International Nuclear Information System (INIS)

DSA is currently the criterion standard for the assessment of dural arteriovenous fistulas (dAVF). Recently, evolving MRA techniques have emerged as a non-invasive alternative. The aim of this study is to assess the value of 3 T MRI in detecting and describing dAVF and to determine whether MRI can replace DSA as diagnostic procedure. A total of 19 patients with dAVF and 19 without dAVF underwent the same MRI protocol, including 3D time-of-flight MRA and time-resolved contrast-enhanced MRA. The images were evaluated retrospectively by three independent readers with different levels of experience blinded to clinical information. The readers assessed the presence, the site, the venous drainage and the feeders of dAVF. Sensitivity, specificity, accuracy, intertechnique and interobserver agreements were calculated. DAVF can be detected with high sensitivity, specificity and accuracy by experienced and also by less experienced readers. However, MRI has limitations when used for grading and evaluation of the angioarchitecture of the dAVF. Different experience, the limited resolution of MRI and its inability to selectively display arteries were the reasons for these limitations. With MRI dAVF can be detected reliably. Nevertheless, at present MRI can not fully replace DSA, especially for treatment planning. (orig.)

2012-02-01

79

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)

2006-03-01

80

Management of breast lesions detectable only on MRI; Abklaerung ausschliesslich MRT-detektierbarer Mammalaesionen  

Energy Technology Data Exchange (ETDEWEB)

Breast MR imaging has become established as the most sensitive imaging method for diagnosing breast cancer. As a result of the increasing examination volume and improved image quality, the number of breast lesions detected only on MRI and requiring further clarification has risen in recent years. According to the S3-guideline 'Diagnosis, Therapy, and Follow-Up of Breast Cancer' as revised in July 2012, institutions performing breast MRI should provide the option of an MRI-guided intervention for clarification. This review describes the indications, methods and results of MRI-guided interventions for the clarification of breast lesions only visible on MRI. Recent guidelines and study results are also addressed and alternative methods and pitfalls are presented. (orig.)

Siegmann-Luz, K.C.; Bahrs, S.D.; Preibsch, H.; Hattermann, V.; Claussen, C.D. [Universitaetsklinikum Tuebingen (Germany). Abt. Diagnostische und Interventionelle Radiologie

2014-01-15

 
 
 
 
81

Does MRI-Detected Cranial Nerve Involvement Affect the Prognosis of Locally Advanced Nasopharyngeal Carcinoma Treated with Intensity Modulated Radiotherapy?  

Science.gov (United States)

Nasopharyngeal carcinoma (NPC) is one of the common cancers in South China. It can easily invade into cranial nerves, especially in patients with local advanced disease. Despite the fact that the magnetic resonance imaging (MRI) findings are not always consistent with the symptoms of CN palsy, MRI is recommended for the detection of CN involvement (CNI). However, the prognostic impact of MRI-detected CNI in NPC patients is still controversial. To investigate the prognostic value of MRI detected CNI, we performed a retrospective analysis on the clinical data of 375 patients with NPC who were initially diagnosed by MRI. All patients had T3-4 disease and received radical intensity modulated radiation therapy (IMRT) as their primary treatment. The incidence of MRI-detected CNI was 60.8%. A higher incidence of MRI-detected CNI was observed in T4 disease compared with T3 disease (96.8% vs. 42.8%, PT4 disease (PT4 disease.

Zong, Jingfeng; Lin, Shaojun; Chen, Yunbin; Wang, Bingyi; Xiao, Youping; Lin, Jin; Li, Rui; Pan, Jianji

2014-01-01

82

Building multiclass classifiers for remote homology detection and fold recognition  

Directory of Open Access Journals (Sweden)

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.

Karypis George

2006-10-01

83

Remote detection of chemicals by millimeter-wave spectroscopy  

Energy Technology Data Exchange (ETDEWEB)

This paper discusses the development and field testing of a remote chemical detection system that is based on millimeter-wave (mm-wave) spectroscopy. The mm-wave system is a monostatic swept-frequency radar that consists of a mm-wave sweeper, a hot-electron-bolometer detector, and a trihedral reflector. The chemical plume to be detected is situated between the transmitter/detector and the reflector. Millimeter-wave absorption spectra of chemicals in the plume are determined by measuring the swept-frequency radar return signals with and without the plume in the beam path. The problem of pressure broadening, which hampered open-path spectroscopy in the past, has been mitigated in this work by designing a fast sweeping source over a broad frequency range. The heart of the system is a Russian backward-wave oscillator (BWO) tube that can be tuned over 225--315 GHz. A mm-wave sweeper that includes the BWO tube was built to sweep the entire frequency range within 10 ms. The radar system was field-tested at the DOE Nevada Test Site at a standoff distance of 60 m. Methyl chloride was released from a wind tunnel that produced a 2-m diameter plume at its exit point. The mm-wave system detected methyl chloride plumes down to a concentration of 12 ppm. The measurement results agree well with model-fitted data. Remote or standoff sensing of airborne chemicals is gaining importance for arms control and treaty verification, intelligence collection, and environmental monitoring.

Gopalsami, N.; Raptis, A.C.

1998-09-01

84

Volume based DCE-MRI breast cancer detection with 3D visualization system  

International Nuclear Information System (INIS)

In this paper, a computer aided design auto probing system is presented to detect breast lesions based on Dynamic contrast enhanced Magnetic resonance imaging (DCE-MRI) images. The system is proposed in order to aid the radiologists and doctors in the interpretation of MRI breast images and enhance the detection accuracy. A series of approaches are presented to enhance the detection accuracy and refine the breast region of interest (Roil) automatically. Besides, a semi-quantitative analysis is used to segment the breast lesions from selected breast Roil and classify the detected tumour is whether benign, suspicious or malignant. The entire breast Roil including the detected tumour will display in 3D. The methodology has been applied on 104 sets of digital imaging and communications in medicine (Dico) breast MRI datasets images. The biopsy results are verified by 2 radiologists from Hospital Malaysia. The experimental results are demonstrated the proposed scheme can precisely identify breast cancer regions with 93% accuracy. (author)

2011-04-01

85

Remote detection of organics using Fourier transform infrared spectroscopy  

International Nuclear Information System (INIS)

Fourier transform infrared (FTIR) spectroscopy is an ideal technique for remote detection of organic emissions. There is an atmospheric window in the 1200 to 800 cm"-"1 region, which corresponds to the ''fingerprint'' region for organic molecules. Virtually all organic molecules have a unique absorption/emission pattern in the fingerprint region. A remote-passive FTIR relies on ambient emission of infrared energy from organics to obtain spectra. The instrumentation consists of inlet optics, and interferometer, a mercury cadmium telluride (MCT) detector, and an on-board computer. The transportable unit measures 40 cm by 50 cm and has been used to collect data while mounted on a helicopter or ground vehicle. Through the use of this FTIR combined with least squares software, it is possible to analyze qualitatively and quantitatively for organic vapors from either the air or ground. The data presented will include quantitative releases of common organics present in incinerator stacks, hazardous wastes, and illegal laboratories. Data will be presented for pure compounds, mixtures, and target analytes in the presence of interfering compounds. The sensitivity, reproducibility, and the potential of the technique will be discussed. 1 ref., 8 figs., 6 tabs

1990-02-12

86

A Comprehensive Segmentation, Registration, and Cancer Detection Scheme on 3 Tesla In Vivo Prostate DCE MRI  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Recently, high resolution 3 Tesla (T) Dynamic Contrast-Enhanced MRI (DCE-MRI) of the prostate has emerged as a promising technique for detecting prostate cancer (CaP). Computer-aided diagnosis (CAD) schemes for DCE-MRI data have thus far been primarily developed for breast cancer and typically involve model fitting of dynamic intensity changes as a function of contrast agent uptake by the lesion, as done by schemes such as the 3 time point (TP) scheme. Non-linear dimensionality reduction sche...

Viswanath, Satish; Bloch, Nicholas; Rofsky, Neil; Lenkinski, Robert; Genega, Elisabeth; Chappelow, Jonathan; Toth, Robert; Madabhushi, Anant

2008-01-01

87

Scintigraphic detection of remote transmural myocardial infarction with thallium-201  

International Nuclear Information System (INIS)

This study was undertaken to assess the value of the thallium-201-scintigram in the detection of remote myocardial infarction with respect to localization and extent as well as the degree of impairment of left ventricular wall motion. 114 patients with typical history of infarction, unequivocal ECG changes and angiographically-documented irreversible asynergy were investigated and 25 healthy subjects served as controls. Electrocardiographic classification of infarction as extensive or non-extensive was based on number of leads involved. The thallium-201-scintigrams were visually analyzed for evaluation of each of 3 segments in all 6 recorded projections. The angiograms were evaluated with respect to regional wall motion derived for the semi-axis shortening of the 3 corresponding scintigraphic segments in the right and left anterior oblique projections. Standard classification of localization and degree of asynergy were employed. (orig.) 891 AJ/orig. 892 MB

1979-01-01

88

Detecting and assessing macrophages in vivo to evaluate atherosclerosis noninvasively using molecular MRI  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We investigated the ability of targeted immunomicelles to detect and assess macrophages in atherosclerotic plaque using MRI in vivo. There is a large clinical need for a noninvasive tool to assess atherosclerosis from a molecular and cellular standpoint. Macrophages play a central role in atherosclerosis and are associated with plaques vulnerable to rupture. Therefore, macrophage scavenger receptor (MSR) was chosen as a target for molecular MRI. MSR-targeted immunomicelles, micelles, and gado...

Amirbekian, Vardan; Lipinski, Michael J.; Briley-saebo, Karen C.; Amirbekian, Smbat; Aguinaldo, Juan Gilberto S.; Weinreb, David B.; Vucic, Esad; Frias, Juan C.; Hyafil, Fabien; Mani, Venkatesh; Fisher, Edward A.; Fayad, Zahi A.

2007-01-01

89

The accuracy of MRI in the detection of Lumbar Disc Containment  

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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 insufficient...

2008-01-01

90

Does MRI-Detected Cranial Nerve Involvement Affect the Prognosis of Locally Advanced Nasopharyngeal Carcinoma Treated with Intensity Modulated Radiotherapy?  

Science.gov (United States)

Nasopharyngeal carcinoma (NPC) is one of the common cancers in South China. It can easily invade into cranial nerves, especially in patients with local advanced disease. Despite the fact that the magnetic resonance imaging (MRI) findings are not always consistent with the symptoms of CN palsy, MRI is recommended for the detection of CN involvement (CNI). However, the prognostic impact of MRI-detected CNI in NPC patients is still controversial. To investigate the prognostic value of MRI detected CNI, we performed a retrospective analysis on the clinical data of 375 patients with NPC who were initially diagnosed by MRI. All patients had T3-4 disease and received radical intensity modulated radiation therapy (IMRT) as their primary treatment. The incidence of MRI-detected CNI was 60.8%. A higher incidence of MRI-detected CNI was observed in T4 disease compared with T3 disease (96.8% vs. 42.8%, PCNI, was superior to that of patients with T4 disease (PCNI. The survival of Stage III patients with or without MRI-detected CNI was significantly superior to that of Stage IV patients (PCNI for all endpoints. Therefore, when treated with IMRT, MRI-detected CNI in patients with NPC does not appear to affect the prognosis. In patients with clinical T3 disease, the presence of MRI-detected CNI is not sufficient evidence for defining T4 disease. PMID:24963626

Zong, Jingfeng; Lin, Shaojun; Chen, Yunbin; Wang, Bingyi; Xiao, Youping; Lin, Jin; Li, Rui; Pan, Jianji

2014-01-01

91

Active remote detection of radioactivity based on electromagnetic signatures  

Energy Technology Data Exchange (ETDEWEB)

This paper presents a new concept for the remote detection of radioactive materials. The concept is based on the detection of electromagnetic signatures in the vicinity of radioactive material and can enable stand-off detection at distances greater than 100?m. Radioactive materials emit gamma rays, which ionize the surrounding air. The ionized electrons rapidly attach to oxygen molecules forming O{sub 2}{sup ?} ions. The density of O{sub 2}{sup ?} around radioactive material can be several orders of magnitude greater than background levels. The elevated population of O{sub 2}{sup ?} extends several meters around the radioactive material. Electrons are easily photo-detached from O{sub 2}{sup ?} ions by laser radiation. The photo-detached electrons, in the presence of laser radiation, initiate avalanche ionization which results in a rapid increase in electron density. The rise in electron density induces a frequency modulation on a probe beam, which becomes a direct spectral signature for the presence of radioactive material.

Sprangle, P. [Plasma Physics Division, Naval Research Laboratory, Washington, District of Columbia 20375 (United States); University of Maryland, College Park, Maryland 20742-4111 (United States); Hafizi, B. [Plasma Physics Division, Naval Research Laboratory, Washington, District of Columbia 20375 (United States); Milchberg, H.; Nusinovich, G. [University of Maryland, College Park, Maryland 20742-4111 (United States); Zigler, A. [University of Maryland, College Park, Maryland 20742-4111 (United States); Icarus Research, Inc., PO Box 30780, Bethesda, Maryland 20824-0780 (United States); The Hebrew University of Jerusalem, Jerusalem (Israel)

2014-01-15

92

Fast spin echo MRI and bone scintigraphy in the detection of skeletal metastases  

International Nuclear Information System (INIS)

Twenty-one patients with a suspicion of carcinomatous bone metastases were evaluated with both conventional T1 weighted (T1w), T2 weighted (T2w) and fast T2w SE (FSE) sequences (thoraco-lumbar spine and pelvis) and whole body bone scintigraphy. Conventional and fast T2w SE sequences detected the same number of lesions while bone scintigraphy detected only 70% of the lesions seen on MRI. However, more importantly, in 11 of the 21 patients bone scintigraphy detected lesions outside the MR field of view, lying in the ribs, skull, scapulae and extremities and in 4 of them, MRI was negative. Our results suggest first that fast SE MRI can replace conventional SE MRI when looking for carcinomatous bone metastases in the axial skeleton, with the advantage of a four to six times reduced acquisition time for fast T2w sequences. However, the limited field of view still limits the usefulness of MRI and whole body bone scintigraphy remains the screening modality for bone metastases. Fast MRI plays an important complementary role. (orig.)

1993-08-01

93

Vehicle Accident Automatic Detection and Remote Alarm Device  

Directory of Open Access Journals (Sweden)

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

Varsha Goud

2012-06-01

94

A comprehensive system for evaluation of remote sequence similarity detection  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Accurate and sensitive performance evaluation is crucial for both effective development of better structure prediction methods based on sequence similarity, and for the comparative analysis of existing methods. Up to date, there has been no satisfactory comprehensive evaluation method that (i is based on a large and statistically unbiased set of proteins with clearly defined relationships; and (ii covers all performance aspects of sequence-based structure predictors, such as sensitivity and specificity, alignment accuracy and coverage, and structure template quality. Results With the aim of designing such a method, we (i select a statistically balanced set of divergent protein domains from SCOP, and define similarity relationships for the majority of these domains by complementing the best of information available in SCOP with a rigorous SVM-based algorithm; and (ii develop protocols for the assessment of similarity detection and alignment quality from several complementary perspectives. The evaluation of similarity detection is based on ROC-like curves and includes several complementary approaches to the definition of true/false positives. Reference-dependent approaches use the 'gold standard' of pre-defined domain relationships and structure-based alignments. Reference-independent approaches assess the quality of structural match predicted by the sequence alignment, with respect to the whole domain length (global mode or to the aligned region only (local mode. Similarly, the evaluation of alignment quality includes several reference-dependent and -independent measures, in global and local modes. As an illustration, we use our benchmark to compare the performance of several methods for the detection of remote sequence similarities, and show that different aspects of evaluation reveal different properties of the evaluated methods, highlighting their advantages, weaknesses, and potential for further development. Conclusion The presented benchmark provides a new tool for a statistically unbiased assessment of methods for remote sequence similarity detection, from various complementary perspectives. This tool should be useful both for users choosing the best method for a given purpose, and for developers designing new, more powerful methods. The benchmark set, reference alignments, and evaluation codes can be downloaded from ftp://iole.swmed.edu/pub/evaluation/.

Kim Bong-Hyun

2007-08-01

95

Detection of Cardiac Infarction in MRI C-SENC Images  

Directory of Open Access Journals (Sweden)

Full Text Available Composite Strain Encoding (C-SENC is an Magnetic Resonance Imaging (MRI technique for acquiring simultaneous viability and functional and images of the heart. It combines two imaging techniques, Delayed Enhancement (DE and Strain Encoding (SENC. In this work, a novel multi-stage method is proposed to identify ventricular infarction in the functional and viability images provided by C-SENC MRI. The proposed method is based on sequential application of Otsu’s thresholding, morphological opening, square boundary tracing and the subtractive clustering algorithm. This method is tested on images of ten patients with and without myocardial infarction (MI. The resulting clustered images are compared with those marked up by expert cardiologists who assisted in validating results coming from the proposed method. Infarcted tissues are correctly identified using the proposed method with high levels of sensitivity and specificity.

Ahmad O. Algohary

2010-10-01

96

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

Directory of Open Access Journals (Sweden)

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

Dubrow SA

2014-04-01

97

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

98

Remote-excitation and remote-detection of single quantum dot using propagating surface plasmons on silver nanowire  

CERN Document Server

Using propagating surface plasmons (SPs) on silver nanowire (NW), we demonstrate that focused laser light at the end of silver nanowire can excite single quantum dot (QD) microns away from the excitation spot. The QD-NW interaction allows the excited QD convert part of its energy into propagating SPs which then can be detected at the remote sites. Simultaneous multi-QDs remote-excitation and detection are also realized. Furthermore, the tight confinement of propagating SPs around the NW surface enables selective excitation of QDs very close in space, which cannot be realized under conventional excitation condition. This remote excitation and detection approach may find applications in optical imaging and sensing of chemical and biological systems.

Li, Qiang; Xu, Hong-Xing

2014-01-01

99

REMOTE DETECTION OF RADIOACTIVE PLUMES USING MILLIMETER WAVE TECHNOLOGY  

Energy Technology Data Exchange (ETDEWEB)

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.

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

2009-01-01

100

Microfluidic gas flow profiling using remote detection NMR  

Energy Technology Data Exchange (ETDEWEB)

Miniaturized fluid handling devices have recently attracted considerable interest in many areas of science1. Such microfluidic chips perform a variety of functions, ranging from analysis of biological macromolecules2,3 to catalysis of reactions and sensing in the gas phase4,5. To enable precise fluid handling, accurate knowledge of the flow properties within these devices is important. Due to low Reynolds numbers, laminar flow is usually assumed. However, either by design or unintentionally, the flow characteristic in small channels is often altered, for example by surface interactions, viscous and diffusional effects, or electrical potentials. Therefore, its prediction is not always straight-forward6-8. Currently, most microfluidic flow measurements rely on optical detection of markers9,10, requiring the injection of tracers and transparent devices. Here, we show profiles of microfluidic gas flow in capillaries and chip devices obtained by NMR in the remote detection modality11,12. Through the transient measurement of dispersion13, NMR is well adaptable for non-invasive, yet sensitive determination of the flow field and provides a novel and potentially more powerful tool to profile flow in capillaries and miniaturized flow devices.

Hilty, Christian; McDonnell, Erin; Granwehr, Josef; Pierce,Kimberly; Han, Song-I Han; Pines, Alexander

2005-05-06

 
 
 
 
101

Detecting and assessing macrophages in vivo to evaluate atherosclerosis noninvasively using molecular MRI.  

Science.gov (United States)

We investigated the ability of targeted immunomicelles to detect and assess macrophages in atherosclerotic plaque using MRI in vivo. There is a large clinical need for a noninvasive tool to assess atherosclerosis from a molecular and cellular standpoint. Macrophages play a central role in atherosclerosis and are associated with plaques vulnerable to rupture. Therefore, macrophage scavenger receptor (MSR) was chosen as a target for molecular MRI. MSR-targeted immunomicelles, micelles, and gadolinium-diethyltriaminepentaacetic acid (DTPA) were tested in ApoE-/- and WT mice by using in vivo MRI. Confocal laser-scanning microscopy colocalization, macrophage immunostaining and MRI correlation, competitive inhibition, and various other analyses were performed. In vivo MRI revealed that at 24 h postinjection, immunomicelles provided a 79% increase in signal intensity of atherosclerotic aortas in ApoE-/- mice compared with only 34% using untargeted micelles and no enhancement using gadolinium-DTPA. Confocal laser-scanning microscopy revealed colocalization between fluorescent immunomicelles and macrophages in plaques. There was a strong correlation between macrophage content in atherosclerotic plaques and the matched in vivo MRI results as measured by the percent normalized enhancement ratio. Monoclonal antibodies to MSR were able to significantly hinder immunomicelles from providing contrast enhancement of atherosclerotic vessels in vivo. Immunomicelles provided excellent validated in vivo enhancement of atherosclerotic plaques. The enhancement seen is related to the macrophage content of the atherosclerotic vessel areas imaged. Immunomicelles may aid in the detection of high macrophage content associated with plaques vulnerable to rupture. PMID:17215360

Amirbekian, Vardan; Lipinski, Michael J; Briley-Saebo, Karen C; Amirbekian, Smbat; Aguinaldo, Juan Gilberto S; Weinreb, David B; Vucic, Esad; Frias, Juan C; Hyafil, Fabien; Mani, Venkatesh; Fisher, Edward A; Fayad, Zahi A

2007-01-16

102

Application of MultiScale Hidden Markov Modeling Wavelet Coefficients to fMRI Activation Detection  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Problem Statement: The problem of detection of functional magnetic resonance images (fMRIs), that is, to decide active and nonactive regions of human brain from fMRIs is studied in this paper. fMRI research is finding and will find more and more applications in diagnosing and treating brain diseases like depression and schizophrenia. At its initial stage fMRI detection are pixel-wise methods, which do not take advantage of mutual information among neighboring pixels. Ignoring such spat...

Fangyuan Nan; Yaonan Wang; Xiaoping Ma

2008-01-01

103

Polarimetric lidar signatures for remote detection of biological warfare agents  

Science.gov (United States)

Polarimetric Lidar has been recently proposed as a method for remote detection of aerosolized biological warfare agents. Accurate characterization of the optical signatures for both biological agents and environmental interferents is a critical first step toward successful sensor deployment. MIT Lincoln Laboratory has developed the Standoff Aerosol Active Signature Testbed (SAAST) as a tool for characterizing aerosol elastic scattering cross sections.1 The spectral coverage of the SAAST includes both the nearinfrared (1-1.6 ?m) and mid-infrared (3-4 ?m) spectral regions. The SAAST source optics are capable of generating all six classic optical polarization states, while the polarization-sensitive receiver is able to reconstruct the full Stokes vector of the scattered wave. All scattering angles, including those near direct backscatter, can be investigated. The SAAST also includes an aerosol generation system capable of producing biological and inert samples with various size distributions. This paper discusses the underlying scattering phenomenology, SAAST design details, and presents some representative data.

Richardson, Jonathan M.; Aldridge, John C.; Milstein, Adam B.

2008-05-01

104

Influence of clinical information on the diagnostic validity of MRI in the detection of abacterial sacroiliitis  

International Nuclear Information System (INIS)

Purpose: to evaluate the influence of clinical information on the diagnostic validity of MRI in the detection of abacterial sacroiliitis. Evaluation of sensitivities, specificities, negative (NPV) and positive predictive values (PPV) for MRI with and without clinical information in comparison to a prior defined standard. Materials and methods: the results of routine MRI reports of 65 patients with the clinical suspicion of abacterial sacroiliitis referred by rheumatologists for MR assessment of the sacroiliac joints were retrospectively reviewed. These results were compared to the results of a blinded reading of the same examinations performed without any clinical information. The MRI protocol included T1-SE, STIR and T1-SE contrast-enhanced sequences with fat saturation. All patients were followed for at least four years. The standard of reference was defined by an experienced rheumatologist and included baseline and follow-up data (clinical, laboratory and imaging). Abacterial sacroiliitis was diagnosed in 19 patients. Results: under routine clinical conditions, MRI revealed a sensitivity of 94.7% and specificity of 97.8%. A PPV of 94.7% and a NPV of 97.8% were achieved. Without clinical information, MRI revealed a sensitivity and specificity of 64 and 80%, and a PPV of 49% and a NPV of 86%, respectively. Conclusion: the additional knowledge of clinical information for the MR diagnosis of abacterial sacroiliitis increases its diagnostic value for the assessment of abacterial sacroiliitis. (orig.)

2005-06-01

105

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

Energy Technology Data Exchange (ETDEWEB)

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.)

Jackowski, Christian [University Hospital, University of Linkoeping, Center for Medical Image Science and Visualization, CMIV, Linkoeping (Sweden); Department of Forensic Medicine, Linkoeping (Sweden); University of Zuerich, Institute of Legal Medicine, Zuerich (Switzerland); Warntjes, Marcel J.B.; Persson, Anders [University Hospital, University of Linkoeping, Center for Medical Image Science and Visualization, CMIV, Linkoeping (Sweden); Berge, Johan [Department of Forensic Medicine, Linkoeping (Sweden); Baer, Walter [University of Zuerich, Institute of Legal Medicine, Zuerich (Switzerland)

2011-01-15

106

Whole-body MRI in comparison to skeletal scintigraphy for detection of skeletal metastases in patients with solid tumors  

International Nuclear Information System (INIS)

The aim of this study was to compare the diagnostic efficacy of whole-body magnetic resonance imaging (WB-MRI) as a new and rapid examination technique with skeletal scintigraphy for detection of skeletal metastases from solid tumors. In 129 patients with solid malignant tumors, WB-MRI was performed for individual comparison with skeletal scintigraphy. Examinations were performed with the innovative AngioSURF trademark rolling table with integrated phased array surface coil and coronary TIRM sequences for different body regions. The results for WB-MRI and skeletal scintigraphy were concordant in 81% of the cases, whereby both procedures excluded skeletal metastases in 43%. WB-MRI and skeletal scintigraphy demonstrated skeletal metastases in 38% of the cases, whereby WB-MRI provided more comprehensive findings in 45%. In 12% of the cases, skeletal scintigraphy was superior to WB-MRI and in 19% the findings were discordant, whereby WB-MRI detected skeletal metastases in 15 cases which had not been found on skeletal scintigraphy. In nine cases, skeletal scintigraphy was positive when the WB-MRI was negative. In 60% of the cases, WB-MRI evidenced tumor-associated findings. WB-MRI represents a promising new staging technique for detection of skeletal metastases, which is more sensitive in many cases than skeletal scintigraphy in detecting and assessing the extent of skeletal metastases - and tumor-associated findings that are relevant for treatment strategy. (orig.)

2004-01-01

107

Detection and Demarcation of Tumor using Vector Quantization in MRI images  

CERN Document Server

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.

Kekre, H B; Gharge, Saylee M

2010-01-01

108

Detection of Septic System Performance via Remote Sensing Technologies  

Science.gov (United States)

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.

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

2005-05-01

109

SQUID-Detected Microtesla MRI in the presence of Metal  

Energy Technology Data Exchange (ETDEWEB)

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.

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

2006-09-06

110

SQUID-Detected Microtesla MRI in the presence of Metal  

International Nuclear Information System (INIS)

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

2006-09-06

111

Whole body MRI for detecting metastatic bone tumor. Comparison with bone scintigrams  

International Nuclear Information System (INIS)

The purpose of this study was to compare the effectiveness of whole body MRI (WB-MRI [magnetic resonance imaging]) and bone scintigram (BS) at detecting bone metastasis. WB-MRI was performed on 16 patients for detecting bone metastasis (6 breast carcinoma, 7 prostatic carcinoma, 1 renal cell carcinoma [RCC], 1 hepatocellular carcinoma [HCC], and 1 primary unknown). BS was also performed in all cases. Patients were placed on a table top extender (Philips Medical Systems). The maximal longitudinal field of view (FOV) was 200 cm. At first, the total spine was imaged in the sagittal plane with a three-station approach for two image sets (fast spin-echo [SE] T1-weighted images [T1WI] and short tau inversion recovery [STIR] images). The whole body was then imaged in the coronal plane with a seven-station approach for two image sets (fast field echo [FFE] T1WI and STIR). Total examination time, including patient positioning, was within 40 min. Three independent radiologists interpreted the imaging data. WB-MRI identified 5 cases of 24 lesions as bone metastasis, while BS identified 3 cases of 25 lesions. Concordance between WB-MRI and BS was seen in 3 cases of 22 lesions (81%). For two cases of 2 lesions, which were identified only with WB-MRI, the lesions were located in the sacrum and thoracic spine. For one case of 3 lesions, which was identified only with BS, the lesions were located in the skull and rib. WB-MRI was an excellent method for screening bone metastasis, especially the vertebral body. (author)

2005-06-01

112

Magnetic CoPt nanoparticles as MRI contrast agent for transplanted neural stem cells detection.  

Science.gov (United States)

Neural stem cells (NSCs) exhibit features that make them suitable candidates for stem cell replacement therapy and spinal cord reconstruction. Magnetic resonance imaging (MRI) offers the potential to track cells in vivo using innovative approaches to cell labeling and image acquisition. In this study, experiments were carried out to optimize the loading condition of magnetic CoPt hollow nanoparticles (CoPt NPs) into neural stem cells and to define appropriate MRI parameters. Both cell viability and multipotency analysis showed that CoPt NPs at a concentration of 16 µg ml(-1) reduced T2 relaxation times in labeled rat NSCs, producing greater contrast on spin echo acquisitions at 4.7 T, yet did not affect cell viability and in vitro differentiation potential compared to controls. After optimizing nanoparticle loading concentrations and labeled cell numbers for MRI detection, CoPt-loaded NSCs were transplanted into organotypic spinal cord slices. The results showed that MRI could efficiently detect low numbers of CoPt-labeled NSCs with the enhanced image contrast. Our study demonstrated that MRI of grafted NSCs labeled with CoPt NPs is a useful tool to evaluate organotypic spinal cord slice models and has potential applications in other biological systems. PMID:21293831

Meng, Xiaoting; Seton, Hugh C; Lu, Le T; Prior, Ian A; Thanh, Nguyen T K; Song, Bing

2011-03-01

113

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

1999-06-01

114

Magnetic CoPt nanoparticles as MRI contrast agent for transplanted neural stem cells detection  

Science.gov (United States)

Neural stem cells (NSCs) exhibit features that make them suitable candidates for stem cell replacement therapy and spinal cord reconstruction. Magnetic resonance imaging (MRI) offers the potential to track cells in vivo using innovative approaches to cell labeling and image acquisition. In this study, experiments were carried out to optimize the loading condition of magnetic CoPt hollow nanoparticles (CoPt NPs) into neural stem cells and to define appropriate MRI parameters. Both cell viability and multipotency analysis showed that CoPt NPs at a concentration of 16 µg ml-1 reduced T2 relaxation times in labeled rat NSCs, producing greater contrast on spin echo acquisitions at 4.7 T, yet did not affect cell viability and in vitro differentiation potential compared to controls. After optimizing nanoparticle loading concentrations and labeled cell numbers for MRI detection, CoPt-loaded NSCs were transplanted into organotypic spinal cord slices. The results showed that MRI could efficiently detect low numbers of CoPt-labeled NSCs with the enhanced image contrast. Our study demonstrated that MRI of grafted NSCs labeled with CoPt NPs is a useful tool to evaluate organotypic spinal cord slice models and has potential applications in other biological systems.

Meng, Xiaoting; Seton, Hugh C.; Lu, Le T.; Prior, Ian A.; Thanh, Nguyen T. K.; Song, Bing

2011-03-01

115

MRI brain tumor segmentation and necrosis detection using adaptive Sobolev snakes  

Science.gov (United States)

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.

Nakhmani, Arie; Kikinis, Ron; Tannenbaum, Allen

2014-03-01

116

The accuracy of MRI in the detection of Lumbar Disc Containment  

Directory of Open Access Journals (Sweden)

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.

Weiner Bradley K

2008-10-01

117

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

Energy Technology Data Exchange (ETDEWEB)

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.

Kim, Myung Joon; Lim, Joon Seok; Yoon, Choon Sik; Han, Sang Won [Yonsei Univ. College of Medicine, Seoul (Korea, Republic of)

1999-06-01

118

Remote detection of hydrocarbons in water by four-photon polarization Raman spectroscopy  

Energy Technology Data Exchange (ETDEWEB)

The use of four-photon spectroscopy based on the Kerr effect associated with Raman scattering for the remote detection of small hydrocarbon concentrations in water is reported. The minimal concentration of benzene in water detectable by this method is 30 parts per million. The possibility of further improving this detection threshold is discussed. It is recommended that the method be used for the quick and remote identification of oil pollutants in the ocean.

Bunkin, A.F.; Galumian, A.S.; Maltsev, D.V.; Surskii, K.O.

1986-07-01

119

Prospective, intraindividual comparison of MRI versus MDCT for endoleak detection after endovascular repair of abdominal aortic aneurysms  

International Nuclear Information System (INIS)

This study compares MRI and MDCT for endoleak detection after endovascular repair of abdominal aortic aneurysms (EVAR). Forty-three patients with previous EVAR underwent both MRI (2D T1-FFE unenhanced and contrast-enhanced; 3D triphasic contrast-enhanced) and 16-slice MDCT (unenhanced and biphasic contrast-enhanced) within 1 week of each other for endoleak detection. MRI was performed by using a high-relaxivity contrast medium (gadobenate dimeglumine, MultiHance registered). Two blinded, independent observers evaluated MRI and MDCT separately. Consensus reading of MRI and MDCT studies was defined as reference standard. Sensitivity, specificity, and accuracy were calculated and Cohen's k statistics were used to estimate agreement between readers. Twenty endoleaks were detected in 18 patients at consensus reading (12 type II and 8 indeterminate endoleaks). Sensitivity, specificity, and accuracy for endoleak detection were 100%, 92%, and 96%, respectively, for reader 1 (95%, 81%, 87% for reader 2) for MRI and 55%, 100%, and 80% for reader 1 (60%, 100%, 82% for reader 2) for MDCT. Interobserver agreement was excellent for MDCT (k = 0.96) and good for MRI (k = 0.81). MRI with the use of a high-relaxivity contrast agent is significantly superior in the detection of endoleaks after EVAR compared with MDCT. MRI may therefore become the preferred technique for patient follow-up after EVAR. (orig.)

2009-05-01

120

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 variables remain difficult. This study investigates machine learning algorithms that automatically identify relevant data attributes for depression detection. Different machine learning techniques are studied for depression classification based on attributes extracted from structural MRI (sMRI data. The attributes include volume calculated from whole brain, white matter, grey matter and hippocampus. Attributes subset selection is performed aiming to remove redundant attributes using three filtering methods and one hybrid method, in combination with ranker search algorithms. The highest average classification accuracy, obtained by using a combination of both SVM-EM and IG-Random Tree algorithms, is 85.23%. The classification approach implemented in this study can achieve higher accuracy than most reported studies using sMRI data, specifically for detection of depression.

Kuryati Kipli

2013-08-01

 
 
 
 
121

Further studies on the remote detection of submerged Orimulsion with a range-gated laser fluorosensor  

International Nuclear Information System (INIS)

A study was conducted to evaluate the capabilities of range-gated laser fluorosensors for the remote, subsurface detection of heavy oils and other products such as Orimulsion. The series of studies initiated by Environment Canada and the Canadian Coast Guard are continuing. They were designed to develop technologies capable of real-time remote detection of neutrally buoyant and/or submerged fuels in the marine environment. In this paper, the authors presented the results of the second phase of the study into the remote detection of submerged Orimulsion with a range-gated fluorosensor. 13 refs., 1 tab., 5 figs

2003-06-10

122

A Comprehensive Segmentation, Registration, and Cancer Detection Scheme on 3 Tesla In Vivo Prostate DCE MRI  

Science.gov (United States)

Recently, high resolution 3 Tesla (T) Dynamic Contrast-Enhanced MRI (DCE-MRI) of the prostate has emerged as a promising technique for detecting prostate cancer (CaP). Computer-aided diagnosis (CAD) schemes for DCE-MRI data have thus far been primarily developed for breast cancer and typically involve model fitting of dynamic intensity changes as a function of contrast agent uptake by the lesion, as done by schemes such as the 3 time point (TP) scheme. Non-linear dimensionality reduction schemes such as locally linear embedding (LLE) have been previously shown to be useful in faithfully embedding high dimensional biomedical data into a lower dimensional subspace while preserving the non-linear geometry of the data manifold. In this paper, we present a novel unsupervised detection scheme for CaP from 3T DCE-MRI that combines LLE and consensus clustering to discriminate between tissue classes at the image pixel level. The methodology comprises 3 distinct steps. First, a multi-attribute active shape model is used to automatically segment the prostate boundary from in vivo 3 T MR imagery. A robust multimodal registration scheme is then used to non-linearly align corresponding whole mount histological and DCE-MRI sections from prostatectomy specimens to determine the spatial extent of CaP. LLE followed by consensus clustering is finally used to identify distinct clusters. Quantitative evaluation on 21 histology-MRI slice pairs against registered CaP ground truth yielded a maximum CaP detection sensitivity of 60.72% and specificity of 83.24% while the popular 3TP scheme gave an accuracy of 38.22%.

Viswanath, Satish; Bloch, Nicholas; Rofsky, Neil; Lenkinski, Robert; Genega, Elisabeth; Chappelow, Jonathan; Toth, Robert; Madabhushi, Anant

2009-01-01

123

Detectability and clinical usefulness of the intraparotid facial nerve on MRI  

International Nuclear Information System (INIS)

The detectability and its clinical usefulness of the intraparotid facial nerve on MRI with SPGR method were investigated. In 18 of 20 normal sides (90%) and in all sides of parotid tumors, intraparotid facial nerve was identified. This result was superior to past reports. In 5 operated cases, the location diagnosis of the parotid tumor was correct in all of 5 cases on MRI, and 3 of 4 cases on CT. In future, we need consider the problems of artifacts and fitting coil for better images. (author)

1995-06-01

124

INFARCT DETECTION IN BRAIN MRI USING IMPROVED SEGMENTATION ALGORITHM AND VOLUME VISUALIZATION?  

Directory of Open Access Journals (Sweden)

Full Text Available In the present days, for the human body anatomical study and for the treatment planning medicalscience very much depend on the medical imaging technology and medical images. Specifically for thehuman brain, MRI widely prefers and using for the imaging. But by nature medical images are complex andnoisy.This leads to the necessity of processes that reduces difficulties in analysis and improves quality ofoutput.This paper discuss about an improved segmentation algorithm for infarct detection in brain MRI andhave compared the performance of this method with conventional method. This Proposed algorithm offersthe advantages of producing good quality segmentation and also easily visualizes the segmented region in 3Dimensional views.

Praveen Kumar E

2013-10-01

125

On the sensitivity of ASL MRI in detecting regional differences in cerebral blood flow  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Arterial-spin-labeling (ASL) MRI provides a non-invasive tool to measure cerebral blood flow (CBF) and is increasingly used as a surrogate for baseline neural activity. However, the power of ASL MRI in detecting CBF differences between patient and control subjects is hampered by inter-subject variations in global CBF, which are associated with non-neural factors and may contribute to the noise in the across-group comparison. Here, we investigated the sensitivity of this technique and proposed...

Aslan, Sina; Lu, Hanzhang

2010-01-01

126

Functional MRI Detection of Deception After Committing a Mock Sabotage Crime*  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Using Blood Oxygen Level Dependent (BOLD) functional MRI (fMRI) to detect deception is feasible in simple laboratory paradigms. A mock sabotage scenario was used to test whether this technology would also be effective in a scenario closer to a real-world situation. Healthy, nonmedicated adults were recruited from the community, screened, and randomized to either a Mock-crime group or a No-crime group. The Mock-crime group damaged and stole compact discs (CDs), which contained incriminating vi...

Kozel, F. Andrew; Johnson, Kevin A.; Grenesko, Emily L.; Laken, Steven J.; Kose, Samet; Lu, Xinghua; Pollina, Dean; Ryan, Andrew; George, Mark S.

2009-01-01

127

Development of CAD System Based on Enhanced Clustering Based Segmentation Algorithm for Detection of Masses in Breast DCE-MRI  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Breast cancer continues to be a significant public health problem in the world. Early detection is the key for improving breast cancer prognosis. Mammography is currently the primary method of early detection. But recent research has shown that many cases missed by mammography can be detected in Breast DCE-MRI. Magnetic Resonance (MR) imaging is emerging as the most sensitive modality that is currently available for the detection of primary or recurrent breast cancer. Breast DCE-MRI is more e...

Janaki Sathya, D.

2011-01-01

128

Remote Raman Detection of Biomarkers on Mineralogical Substrates  

Science.gov (United States)

Remote Raman spectroscopy can be used to identify life signatures and remains of biological activity. In this work we present our develops about the use of this technique for implementation in a planetary exploration payload.

Manrique-Martinez, J. A.; Sansano, A.; Navarro, R. J.; Lopez-Reyes, G.; Rull, F.; Gomez, J. M.

2014-06-01

129

MRI with intrathecal gadolinium to detect a CSF leak: a prospective open label cohort study.  

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Abstract Objectives: The techniques currently used to detect a CSF leak are indium radio nucleotide scan or CT scan with intrathecal iodinated contrast agent. They have a low spatial and temporal resolution and are unpleasant for the patient. This open label prospective observational cohort study was designed to investigate the feasibility, success ratio, complications and therapeutic consequences of MRI with gadolinium administered by lumbar puncture to detect a CSF leak. Met...

2010-01-01

130

Towards targeted MRI: New MRI contrast agents for sialic acid detection  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The detection of sialic acid in living systems is of importance for the diagnosis of several types of malignancy. We have designed and synthesized two new lanthanide ion ligands (L-1 and L-2) that are capable of molecular recognition of sialic acid residues. The basic structure of these ligands consists of a DTPA-bisamide (DTPA, diethylenetriamine pentaacetic acid) whose amide moieties each bear both a boronic function for interaction with the diol groups in the side chain of sialic acid, and...

Aime, Silvio; Frullano, Luca

2004-01-01

131

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.)

2012-02-01

132

A hierarchical model for simultaneous detection and estimation in multi-subject fMRI studies.  

Science.gov (United States)

In this paper we introduce a new hierarchical model for the simultaneous detection of brain activation and estimation of the shape of the hemodynamic response in multi-subject fMRI studies. The proposed approach circumvents a major stumbling block in standard multi-subject fMRI data analysis, in that it both allows the shape of the hemodynamic response function to vary across region and subjects, while still providing a straightforward way to estimate population-level activation. An efficient estimation algorithm is presented, as is an inferential framework that allows for not only tests of activation, but also tests for deviations from some canonical shape. The model is validated through simulations and application to a multi-subject fMRI study of thermal pain. PMID:24793829

Degras, David; Lindquist, Martin A

2014-09-01

133

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)

1988-01-01

134

Detection of the dynamic renal function using MRI by gadolinium-DTPA  

Energy Technology Data Exchange (ETDEWEB)

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.

Torii, Shinichiro; Machida, Toyohei; Ohoishi, Yukihiko; Tateno, Yukio; Fukuda, Nobuo.

1988-06-01

135

Comparison between SPECT and MRI in detecting skull-base invasion in nasopharyngeal carcinoma  

International Nuclear Information System (INIS)

Objective: To investigate the ability of single photon emission computed tomography (SPECT) and MRI in detecting skull-base invasion in nasopharyngeal carcinoma. Methods: Sixty-one patients with nasopharyngeal carcinoma received whole body and skull-base tomography SPECT, and nasopharynx and skull-base MRI before radiotherapy. The results were double-blind compared and evaluated. Results: The overall positive rates of skull-base invasion detected by SPECT and MRI were 51% and 46% (P =0.508). In patients with headache, cranial nerve palsy or both, the rates were 83% and 86% (P= 1.000), 80% and 80% (P=1.000), 88% and 94% (P=1.000 ), respectively. In patients with T1 + T2 and T3 + T4 lesions, the rates were 22% and 0 (P=0.031), 74% and 82% (P=0.250), respectively. In patients with N0 + N1 and N2 + N3 lesions, they were 50% and 48% (P=1.000), 53% and 40% (P= 0.500), respectively. The conformation rate between SPECT and MRI was 85%. Binary Logistic regression analysis showed that T stage was a risk factor for positive SPECT(?2=4.23, P=0.040, OR=3.04). Head- ache tended to be a risk factor for both positive SPECT and positive MRI(?2=3.13, P=0.077, OR=4.54; ?2=3.64, P=0.056, OR=12.00). Conclusions: The detection sensitivity of SPECT in skull-base invasion in nasopharyngeal carcinoma is equivalent to that of MRI. The consistency between SPECT and MRI is good. Moreover, there is a good correlation between SPECT and symptoms, signs and stage. SPECT of skull-base tomography is necessary for patients with severe headache, negative CT and those who can not receive MRI. When SPECT result is positive,skull-base should be considered to be invaded and should be defined as gross tumor volume in radiotherapy planning. (authors)

2008-11-01

136

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

Science.gov (United States)

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. PMID:24403176

Rajendran, Reshmi; Huang, Wei; Tang, Annie Mei Yee; Liang, Jie Ming; Choo, Stephanie; Reese, Torsten; Hentze, Hannes; van Boxtel, Susan; Cliffe, Adam; Rogers, Keith; Henry, Brian; Chuang, Kai Hsiang

2014-02-01

137

Towards Targeted MRI: New MRI Contrast Agents for Sialic Acid Detection  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The detection of sialic acid in living systems is of importance for the diagnosis of several types of malignancy. We have designed and synthesized two new lanthanide ion ligands (L1 and L2) that are capable of molecular recognition of sialic acid residues. The basic structure of these ligands consists of a DTPA-bisamide (DTPA, diethylenetriamine pentaacetic acid) whose amide moieties each bear both a boronic function for interaction with the diol groups in the side chain of sialic acid, and a...

Frullano, Luca; Rohovec, Jan; Aime, Silvio; Maschmeyer, Thomas; Prata, M. Isabel; Lima, J. J. Pedroso; Geraldes, Carlos F. G. C.; Peters, Joop A.

2004-01-01

138

Cloud detection based on HSI color space and SWT from high resolution color remote sensing imagery  

Science.gov (United States)

Cloud is floating in the earth sky widely, irregularly and frequently. So it appears in the satellite imagery. The cloud in the remote sensing imagery especially high resolution remote sensing imagery and aerial image will largely reduce the remote sensing image quality and use ratio, hinder the further application and the subsequent processing. Cloud detection accurately is a necessary and important step in the remote sensing image data analysis processing. So, a new cloud detection method based on HSI color space and stationary wavelet transformation (SWT) according to the spectral properties of cloud and the different with other objects is proposed in this paper. First, transform the RGB to HSI of image; then SWT is implemented to achieve the low frequency; the last result of cloud detection is obtained by the segmentation and edge extraction use SOBLE. The experiments show that the approach can detect the cloud accurately, availably and quickly.

Chen, Zhong; Deng, Tao; Zhou, Heng; Luo, Song

2013-10-01

139

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.)

2010-12-01

140

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

Science.gov (United States)

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.

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

2014-05-01

 
 
 
 
141

The efficacy of plain films vs MRI in the detection of scaphoid fractures  

International Nuclear Information System (INIS)

An investigation was carried out to determine whether or not professionals perceived plain film radiography to be the 'gold-standard' in the detection of scaphoid fractures. Literature highlighted that plain film radiography was an unreliable method for detecting such fractures and that magnetic resonance imaging (MRI) should now be regarded as the new 'gold-standard'. Using a quantitative method, a total of 100 postal questionnaires were sent out to radiologists in 20 different imaging departments throughout the United Kingdom (UK) asking them their opinion on this controversial subject. In addition, the investigation looked into the use of MRI within each department in trying to determine whether or not it was surpassing plain film radiography as an established practice for detecting scaphoid fractures. Of the 100 questionnaires that were sent out, a total of 45 were returned from a total of 13 different departments. The results of this investigation conclude that plain film radiography is still used as a primary imaging modality to detect scaphoid fractures in all departments. There was much support for the use of plain film radiography with the modality being praised time and time again for its ease, 24-h availability, low cost and reproducibility. MRI was acknowledged as being superior in its capability to detect scaphoid fractures in comparison to plain films; its current use, however, is limited owing to high costs, lack of availability and long waiting lists. It would appear from this study that MRI is regarded as a useful modality in cases whereby plain film radiography fails to detect the presence or absence of a fracture in clinically positive patients, with great future potential

2007-02-01

142

The efficacy of plain films vs MRI in the detection of scaphoid fractures  

Energy Technology Data Exchange (ETDEWEB)

An investigation was carried out to determine whether or not professionals perceived plain film radiography to be the 'gold-standard' in the detection of scaphoid fractures. Literature highlighted that plain film radiography was an unreliable method for detecting such fractures and that magnetic resonance imaging (MRI) should now be regarded as the new 'gold-standard'. Using a quantitative method, a total of 100 postal questionnaires were sent out to radiologists in 20 different imaging departments throughout the United Kingdom (UK) asking them their opinion on this controversial subject. In addition, the investigation looked into the use of MRI within each department in trying to determine whether or not it was surpassing plain film radiography as an established practice for detecting scaphoid fractures. Of the 100 questionnaires that were sent out, a total of 45 were returned from a total of 13 different departments. The results of this investigation conclude that plain film radiography is still used as a primary imaging modality to detect scaphoid fractures in all departments. There was much support for the use of plain film radiography with the modality being praised time and time again for its ease, 24-h availability, low cost and reproducibility. MRI was acknowledged as being superior in its capability to detect scaphoid fractures in comparison to plain films; its current use, however, is limited owing to high costs, lack of availability and long waiting lists. It would appear from this study that MRI is regarded as a useful modality in cases whereby plain film radiography fails to detect the presence or absence of a fracture in clinically positive patients, with great future potential.

Trigg, Mark [Bronglais Hospital, Aberystwyth (United Kingdom); Reeves, Pauline Jane [X-Ray Department, Arrowe Park Hospital, Upton, Wirral CH49 5PE (United Kingdom)]. E-mail: pauline.reeves@whnt.nhs.uk

2007-02-15

143

Computerized breast lesions detection using kinetic and morphologic analysis for dynamic contrast-enhanced MRI.  

Science.gov (United States)

To facilitate rapid and accurate assessment, this study proposed a novel fully automatic method to detect and identify focal tumor breast lesions using both kinetic and morphologic features from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). After motion registration of all phases of the DCE-MRI study, three automatically generated lines were used to segment the whole breast region of each slice. The kinetic features extracted from the pixel-based time-signal intensity curve (TIC) by a two-stage detection algorithm was first used, and then three-dimensional (3-D) morphologic characteristics of the detected regions were applied to differentiate between tumor and non-tumor regions. In this study, 95 biopsy-confirmed lesions (28 benign and 67 malignant lesions) in 54 women were used to evaluate the detection efficacy of the proposed system. The detection performance was analyzed using the free-response operating characteristics (FROC) curve and detection rate. The proposed computer-aided detection (CADe) system had a detection rate of 92.63% (88/95) of all tumor lesions, with 6.15 false positives per case. Based on the results, kinetic features extracted by TIC can be used to detect tumor lesions and 3-D morphology can effectively reduce the false positives. PMID:24582545

Chang, Yeun-Chung; Huang, Yan-Hao; Huang, Chiun-Sheng; Chen, Jeon-Hor; Chang, Ruey-Feng

2014-06-01

144

Biocompatible, Biodegradable, and Enzymatic-Cleavable MRI Contrast Agents for Early Detection of Bone Metastatic Breast Cancer.  

Science.gov (United States)

This project proposes to design and test a novel peptide-based MRI contrast agent for early detection of bone metastasis from breast cancer. The proposed imaging agent is consist of bone targeting moiety of Asp8 and MRI imaging moiety of DOTA(Gd) with a c...

X. Wang

2012-01-01

145

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.)

2013-08-01

146

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

Energy Technology Data Exchange (ETDEWEB)

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.)

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

147

Late widespread skeletal metastases from myxoid liposarcoma detected by MRI only  

Science.gov (United States)

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.

Hanna, Sammy A; Qureshi, Yassar A; Bayliss, Lee; David, Lee A; O'Donnell, Paul; Judson, Ian R; Briggs, Timothy WR

2008-01-01

148

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)

1988-01-01

149

Symmetry-based detection and diagnosis of DCIS in breast MRI  

Science.gov (United States)

The delineation and diagnosis of non-mass-like lesions, most notably DCIS (ductal carcinoma in situ), is among the most challenging tasks in breast MRI reading. Even for human observers, DCIS is not always easy to diferentiate from patterns of active parenchymal enhancement or from benign alterations of breast tissue. In this light, it is no surprise that CADe/CADx approaches often completely fail to classify DCIS. Of the several approaches that have tried to devise such computer aid, none achieve performances similar to mass detection and classification in terms of sensitivity and specificity. In our contribution, we show a novel approach to combine a newly proposed metric of anatomical breast symmetry calculated on subtraction images of dynamic contrast-enhanced (DCE) breast MRI, descriptive kinetic parameters, and lesion candidate morphology to achieve performances comparable to computer-aided methods used for masses. We have based the development of the method on DCE MRI data of 18 DCIS cases with hand-annotated lesions, complemented by DCE-MRI data of nine normal cases. We propose a novel metric to quantify the symmetry of contralateral breasts and derive a strong indicator for potentially malignant changes from this metric. Also, we propose a novel metric for the orientation of a finding towards a fix point (the nipple). Our combined scheme then achieves a sensitivity of 89% with a specificity of 78%, matching CAD results for breast MRI on masses. The processing pipeline is intended to run on a CAD server, hence we designed all processing to be automated and free of per-case parameters. We expect that the detection results of our proposed non-mass aimed algorithm will complement other CAD algorithms, or ideally be joined with them in a voting scheme.

Srikantha, Abhilash; Harz, Markus T.; Newstead, Gillian; Wang, Lei; Platel, Bram; Hegenscheid, Katrin; Mann, Ritse M.; Hahn, Horst K.; Peitgen, Heinz-Otto

2013-02-01

150

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2010-01-01

151

Detection of osseous metastases of the spine: Comparison of high resolution multi-detector-CT with MRI  

International Nuclear Information System (INIS)

Purpose: The aim of the study was to evaluate the diagnostic accuracy of multi-slice-computed tomography (MDCT) for the detection of vertebral metastases in comparison to magnetic resonance imaging (MRI). Materials and methods: In a retrospective analysis, 639 vertebral bodies of 41 patients with various histologically confirmed primary malignancies were analysed. The MDCT-images were acquired on a 16/64-row-MDCT scanner (Siemens Somatom Sensation 16/64). MRI was performed on 1.5 T scanners (SIEMENS Symphony/Sonata). The MDCT- and MRI-images were evaluated separately by two experienced radiologists in a consensus reading. The combination of MDCT and MRI in an expert reading including follow-up examinations and/or histology as well as clinical data served as the gold standard. Results: 201/639 vertebral bodies were defined as metastatically affected by the gold standard. In MDCT 133/201 lesions, in MRI 198/201 lesions were detected. 68 vertebral bodies were false negative in MDCT, whereas 3 false negatives were found in MRI. 3 false positive results were obtained in MDCT, 5 in MRI. Sensitivity was significantly lower for MDCT (66.2%) than for MRI (98.5%) (p < 0.0001). Specificity was not significantly different for both methods (MDCT: 99.3%; MRI: 98.9%). The diagnostic accuracy resulted in 88.8% for MDCT and 98.7% for MRI. Conclusion: Although 16/64-row-MDCT provides excellent image quality and a high spatial resolution in the assessment of bony structures, metastatic lesions without significant bone destruction may be missed. The diagnostic accuracy of MRI proved to be significantly superior to 16/64-row-MDCT for the detection of osseous metastases.

2009-03-01

152

Crop stress detection and classification using hyperspectral remote sensing  

Science.gov (United States)

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

Irby, Jon Trenton

153

Clinical evaluation of asymptomatic sinus disease detected by MRI  

Energy Technology Data Exchange (ETDEWEB)

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).

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

1994-12-01

154

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)

1994-12-01

155

Modeling Chemical Detection Sensitivities of Active and Passive Remote Sensing Systems  

Energy Technology Data Exchange (ETDEWEB)

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).

Scharlemann, E T

2003-07-28

156

Detection of rheumatoid arthritis bone erosions by two different dedicated extremity MRI units and conventional radiography  

DEFF Research Database (Denmark)

Objectives: To compare the ability of two different dedicated extremity MRI (E-MRI) units and conventional radiography (CR) for identifying bone erosions in rheumatoid arthritis (RA) metacarpophalangeal (MCP) and wrist joints. Methods: CR and two MRI examinations (using 0.2 T Esaote Artoscan and 0.2 T portable MagneVu MV1000 units) of 418 bones in the dominant wrist and second to fifth MCP joints of 15 patients with RA and 4 healthy controls were performed and evaluated blindly for bones being visible and for erosions. Results: In MCP joints, MagneVu visualised 18.5% of bones entirely and 71.1% were 67-99% visualised. In wrists, MagneVu visualised 1.5% of bones entirely, 39.8% were 67-99% visualised and 19% were not visualised at all. Artoscan and CR visualised all bones entirely. Artoscan, MagneVu and CR found 22, 19 and 15 bones with erosions in MCP joints and 66, 40 and 13 bones with erosions in wrist joints, respectively. With the previously validated Artoscan unit as standard reference, MagneVu and CR had sensitivities of 0.82 and 0.55, respectively, in MCP joint bones and 0.41 and 0.14 in wrist bones. Specificities of CR and MagneVu were comparable (0.82-0.99). The MagneVu unit was particularly more sensitive than CR for metacarpal heads and carpal bones. MagneVu MRI and CR detected 100% and 89%, respectively, of large erosions (Outcome Measures in Rheumatoid Arthritis Clinical Trials-Rheumatoid Arthritis MRI Scoring System (OMERACT-RAMRIS) score >1 on Artoscan) in MCP joints and 69% and 15.8% of large erosions in wrists. Conclusions: Both E-MRI units detected more erosions than CR, in particular due to a higher sensitivity in metacarpal heads and carpal bones. The MagneVu unit detected fewer erosions than the Artoscan unit due to a lower average image quality and a smaller proportion of bones being visualised Udgivelsesdato: 2008/7

Duer-Jensen, A.; Vestergaard, A.

2008-01-01

157

Stress Detection in Crops with Hyperspectral Remote Sensing and Physical Simulation Models  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Progress made on the detection of stress in heterogeneous crop canopies with hyperspectral remote sensing imagery is presented. High-spatial resolution multispectral remote sensing imagery was collected in 2002, 2003 and 2004 over vineyard and olive orchards in Spain. Imagery acquired with the Compact Airborne Spectrographic Imager (CASI) and the Reflective Optics System Imaging Spectrometer (ROSIS) in the visible and near infrared wavelength regions 400-950 nm at 1 m resolution, ...

Zarco-tejada, Pablo J.; Berjo?n, A.; Miller, J. R.

2004-01-01

158

Automatic Cloud Detection and Removal Algorithm for MODIS Remote Sensing Imagery  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 effectiv...

2011-01-01

159

A Novel Datamining Based Approach for Remote Intrusion Detection  

Directory of Open Access Journals (Sweden)

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.

Renu Deepti.S, Loshma.G

2012-06-01

160

Dual Manganese-Enhanced and Delayed Gadolinium-Enhanced MRI Detects Myocardial Border Zone Injury in a Pig Ischemia-Reperfusion Model  

Science.gov (United States)

Background Delayed gadolinium (Gd) enhancement MRI (DEMRI) identifies non-viable myocardium, but is non-specific and may overestimate nonviable territory. Manganese (Mn2+)-enhanced MRI (MEMRI) denotes specific Mn2+ uptake into viable cardiomyocytes. We performed a dual-contrast myocardial assessment in a porcine ischemia-reperfusion (IR) model to test the hypothesis that combined DEMRI and MEMRI will identify viable infarct border zone (BZ) myocardium in vivo. Methods and Results Sixty-minute LAD ischemia-reperfusion injury (IR) was induced in 13 adult swine. Twenty-one days post-IR, 3T cardiac MRI was performed. MEMRI was obtained after injection (0.7 cc/kg) of Mn2+ contrast agent (EVP1001-1, Eagle Vision Pharmaceutical Corp.). DEMRI was then acquired after 0.2mmol/kg Gd injection. Left ventricular (LV) mass, infarct, and function were analyzed. Subtraction of MEMRI defect from DEMRI signal identified injured border zone myocardium. Explanted hearts were analyzed by 2,3,5-triphenyltetrazolium chloride (TTC) stain and tissue electron microscopy (TEM) to compare infarct, BZ, and remote myocardium. Average LV ejection fraction was reduced (30±7%). MEMRI and DEMRI infarct volumes correlated with TTC (MEMRI: r=0.78; DEMRI: r=0.75; p0.05). TEM analysis exhibited preserved cell structure in BZ cardiomyocytes despite transmural DEMRI enhancement. Conclusions Dual-contrast MEMRI-DEMRI detects BZ viability within DEMRI infarct zones. This approach may identify injured, at-risk myocardium in ischemic cardiomyopathy.

Dash, Rajesh; Chung, Jaehoon; Ikeno, Fumiaki; Hahn-Windgassen, Annett; Matsuura, Yuka; Bennett, Mihoko V.; Lyons, Jennifer K.; Teramoto, Tomohiko; Robbins, Robert C.; McConnell, Michael V.; Yeung, Alan C.; Brinton, Todd J.; Harnish, Phillip P.; Yang, Phillip C.

2011-01-01

 
 
 
 
161

Preferred features of a fluorine-19 MRI probe for amyloid detection in the brain.  

Science.gov (United States)

Fluorine-19 magnetic resonance imaging (19F MRI) could be a promising approach for imaging amyloid deposition in the brain. However, the required features of a 19F MRI probe for amyloid detection remain unclear. In the present study, we investigated a series of compounds as potent 19F probes that could prevent the reduction in MR signal when bound to amyloid plaques in the brain. Each compound consists of styrylbenzoxazole as a core structure linked by a different length of polyethylene glycol (PEG) chain to one of three types of fluorine-labeled group: a trifluoroethoxy group, a hexafluoroisopropoxy group, or a 3',5'-bis(trifluoromethyl)benzylamino group. Among these compounds, 6-(3',6',9',15',18',21'-heptaoxa-23',23',23'-trifluoro tricosanyloxy)-2-(4'-dimethylaminostyryl)benzoxazole [compound 3b (m = 6)], which has a trifluoroethoxy group with seven ethylene glycol groups in the PEG chain, showed significant 19F MR signals in the brains of A?PPswe/PS1dE9 double-transgenic mice, but not wild-type mice. This suggested that compound 3b (m = 6) could be a useful 19F MRI probe for amyloid detection. Furthermore, this study identified the most effective length of PEG chain between the fluorine-labeled group and the core structure to ensure a strong MR signal when the probe is bound to amyloid plaques. PMID:24246421

Yanagisawa, Daijiro; Taguchi, Hiroyasu; Ibrahim, Nor Faeizah; Morikawa, Shigehiro; Shiino, Akihiko; Inubushi, Toshiro; Hirao, Koichi; Shirai, Nobuaki; Sogabe, Takayuki; Tooyama, Ikuo

2014-01-01

162

Automatic detection of regional heart rejection in USPIO-enhanced MRI.  

Science.gov (United States)

Contrast-enhanced magnetic resonance imaging (MRI) is useful to study the infiltration of cells in vivo. This research adopts ultrasmall superparamagnetic iron oxide (USPIO) particles as contrast agents. USPIO particles administered intravenously can be endocytosed by circulating immune cells, in particular, macrophages. Hence, macrophages are labeled with USPIO particles. When a transplanted heart undergoes rejection, immune cells will infiltrate the allograft. Imaged by T(2)(*)-weighted MRI, USPIO-labeled macrophages display dark pixel intensities. Detecting these labeled cells in the image facilitates the identification of acute heart rejection. This paper develops a classifier to detect the presence of USPIO-labeled macrophages in the myocardium in the framework of spectral graph theory. First, we describe a USPIO-enhanced heart image with a graph. Classification becomes equivalent to partitioning the graph into two disjoint subgraphs. We use the Cheeger constant of the graph as an objective functional to derive the classifier. We represent the classifier as a linear combination of basis functions given from the spectral analysis of the graph Laplacian. Minimization of the Cheeger constant based functional leads to the optimal classifier. Experimental results and comparisons with other methods suggest the feasibility of our approach to study the rejection of hearts imaged by USPIO-enhanced MRI. PMID:18672427

Chang, Hsun-Hsien; Moura, José M F; Wu, Yijen L; Ho, Chien

2008-08-01

163

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

164

Automatic change detection in multimodal serial MRI: application to multiple sclerosis lesion evolution.  

Science.gov (United States)

The automatic analysis of subtle changes between MRI scans is an important tool for assessing disease evolution over time. Manual labeling of evolutions in 3D data sets is tedious and error prone. Automatic change detection, however, remains a challenging image processing problem. A variety of MRI artifacts introduce a wide range of unrepresentative changes between images, making standard change detection methods unreliable. In this study we describe an automatic image processing system that addresses these issues. Registration errors and undesired anatomical deformations are compensated using a versatile multiresolution deformable image matching method that preserves significant changes at a given scale. A nonlinear intensity normalization method is associated with statistical hypothesis test methods to provide reliable change detection. Multimodal data is optionally exploited to reduce the false detection rate. The performance of the system was evaluated on a large database of 3D multimodal, MR images of patients suffering from relapsing remitting multiple sclerosis (MS). The method was assessed using receiver operating characteristics (ROC) analysis, and validated in a protocol involving two neurologists. The automatic system outperforms the human expert, detecting many lesion evolutions that are missed by the expert, including small, subtle changes. PMID:14568441

Bosc, Marcel; Heitz, Fabrice; Armspach, Jean Paul; Namer, Izzie; Gounot, Daniel; Rumbach, Lucien

2003-10-01

165

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

Energy Technology Data Exchange (ETDEWEB)

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.)

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

2006-11-15

166

Remote detection of single emitters via optical waveguides  

Science.gov (United States)

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.

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

2014-05-01

167

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

Energy Technology Data Exchange (ETDEWEB)

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.

Regge, D. [Radiology Unit, Institute for Cancer Research and Treatment, Candiolo, Turin (Italy)]. E-mail: daniele.regge@ircc.it; Campanella, D. [Radiology Unit, Institute for Cancer Research and Treatment, Candiolo, Turin (Italy); Anselmetti, G.C. [Radiology Unit, Institute for Cancer Research and Treatment, Candiolo, Turin (Italy); Cirillo, S. [Radiology Unit, Institute for Cancer Research and Treatment, Candiolo, Turin (Italy); Gallo, T.M. [Radiology Unit, Institute for Cancer Research and Treatment, Candiolo, Turin (Italy); Muratore, A. [Oncological Surgery Unit, Institute for Cancer Research and Treatment, Candiolo, Turin (Italy); Capussotti, L. [Oncological Surgery Unit, Institute for Cancer Research and Treatment, Candiolo, Turin (Italy); Galatola, G. [Gastroenterology Unit, Institute for Cancer Research and Treatment, Strada Provinciale, Candiolo, Turin (Italy); Floriani, I. [Istituto di Ricerche Farmacologiche Mario Negri, Milan (Italy); Aglietta, M. [Medical Oncology Unit, Institute for Cancer Research and Treatment, Strada Provinciale, Candiolo, Turin (Italy)

2006-04-15

168

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

2006-04-01

169

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

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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.)

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

170

Application of MultiScale Hidden Markov Modeling Wavelet Coefficients to fMRI Activation Detection  

Directory of Open Access Journals (Sweden)

Full Text Available Problem Statement: The problem of detection of functional magnetic resonance images (fMRIs, that is, to decide active and nonactive regions of human brain from fMRIs is studied in this paper. fMRI research is finding and will find more and more applications in diagnosing and treating brain diseases like depression and schizophrenia. At its initial stage fMRI detection are pixel-wise methods, which do not take advantage of mutual information among neighboring pixels. Ignoring such spatial information can reduce detection accuracy. During past decade, many efforts have been focusing on taking advantage of spatial correlation inherent in fMRI data. Most well known is smoothing using a fixed Gaussian filter and the compensation for multiple testing using Gaussian random field theory as used by Statistical Parametric Mapping (SPM. Other methods including wavelets had also been proposed by the community. Approach: In this study a novel two-step approach was put forward that incorporates spatial correlation information and is amenable to analysis and optimization. First, a new multi scale image segmentation algorithm was proposed to decompose the correlation image into several different regions, each of which is of homogeneous statistical behavior. Second, each region will be classified independently as active or inactive using existing pixel-wise test methods. The image segmentation consists of two procedures: Edge detection followed by label estimation. To deduce the presence or absence of an edge from continuous data, two fundamental assumption of our algorithm are 1 each wavelet coefficient was described by a 2-state Gaussian Mixture Model (GMM; 2 across scale, each state is caused by its parent state, hence the Multiscale Hidden Markov Model (MHMM. The states of Markov chain are unknown ("hidden" and represent the presence (state 1 or absence (state 0 of edges. Using this interpretation, the edge detection problem boils down to the posterior state estimation given observation. Results: Data processing results demonstrate much improved efficiency of our algorithm compared with pixel-wise detection methods. Conclusions: Our methods and results stress the importance of spatial-temporal modeling in fMRI research.

Fangyuan Nan

2008-01-01

171

Improved detection of event-related functional MRI signals using probability functions.  

Science.gov (United States)

Selecting an optimal event distribution for experimental use in event-related fMRI studies can require the generation of large numbers of event sequences with characteristics hard to control. The use of known probability distributions offers the possibility to control event timing and constrain the search space for finding optimal event sequences. We investigated different probability distributions in terms of response estimation (estimation efficiency), detectability (detection power, parameter estimation efficiency, sensitivity to true positives), and false-positive activation. Numerous simulated event sequences were generated selecting interevent intervals (IEI) from the uniform, uniform permuted, Latin square, exponential, binomial, Poisson, chi(2), geometric, and bimodal probability distributions and fixed IEI. Event sequences from the bimodal distribution, like block designs, had the best performance for detection and the poorest for estimation, while high estimation and detectability occurred for the long-decay exponential distribution. The uniform distribution also yielded high estimation efficiency, but probability functions with a long tail toward higher IEI, such as the geometric and the chi(2) distributions, had superior detectability. The distributions with the best detection performance also had a relatively high incidence of false positives, in contrast to the ordered distributions (Latin square and uniform permuted). The predictions of improved sensitivities for distributions with long tails were confirmed with empirical data. Moreover, the Latin square design yielded detection of activated voxels similar to the chi(2) distribution. These results indicate that high detection and suitable behavioral designs have compatibility for application of functional MRI methods to experiments requiring complex designs. PMID:11697951

Hagberg, G E; Zito, G; Patria, F; Sanes, J N

2001-11-01

172

High-Resolution Remotely Sensed Small Target Detection by Imitating Fly Visual Perception Mechanism  

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The difficulty and limitation of small target detection methods for high-resolution remote sensing data have been a recent research hot spot. Inspired by the information capture and processing theory of fly visual system, this paper endeavors to construct a characterized model of information perception and make use of the advantages of fast and accurate small target detection under complex varied nature environment. The proposed model forms a theoretical basis of small target detection for hi...

Huang, Fengchen; Xu, Lizhong; Li, Min; Tang, Min

2012-01-01

173

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.)

2004-06-01

174

Multi-kernel graph embedding for detection, Gleason grading of prostate cancer via MRI/MRS.  

Science.gov (United States)

Even though 1 in 6 men in the US, in their lifetime are expected to be diagnosed with prostate cancer (CaP), only 1 in 37 is expected to die on account of it. Consequently, among many men diagnosed with CaP, there has been a recent trend to resort to active surveillance (wait and watch) if diagnosed with a lower Gleason score on biopsy, as opposed to seeking immediate treatment. Some researchers have recently identified imaging markers for low and high grade CaP on multi-parametric (MP) magnetic resonance (MR) imaging (such as T2 weighted MR imaging (T2w MRI) and MR spectroscopy (MRS)). In this paper, we present a novel computerized decision support system (DSS), called Semi Supervised Multi Kernel Graph Embedding (SeSMiK-GE), that quantitatively combines structural, and metabolic imaging data for distinguishing (a) benign versus cancerous, and (b) high- versus low-Gleason grade CaP regions from in vivo MP-MRI. A total of 29 1.5Tesla endorectal pre-operative in vivo MP MRI (T2w MRI, MRS) studies from patients undergoing radical prostatectomy were considered in this study. Ground truth for evaluation of the SeSMiK-GE classifier was obtained via annotation of disease extent on the pre-operative imaging by visually correlating the MRI to the ex vivo whole mount histologic specimens. The SeSMiK-GE framework comprises of three main modules: (1) multi-kernel learning, (2) semi-supervised learning, and (3) dimensionality reduction, which are leveraged for the construction of an integrated low dimensional representation of the different imaging and non-imaging MRI protocols. Hierarchical classifiers for diagnosis and Gleason grading of CaP are then constructed within this unified low dimensional representation. Step 1 of the hierarchical classifier employs a random forest classifier in conjunction with the SeSMiK-GE based data representation and a probabilistic pairwise Markov Random Field algorithm (which allows for imposition of local spatial constraints) to yield a voxel based classification of CaP presence. The CaP region of interest identified in Step 1 is then subsequently classified as either high or low Gleason grade CaP in Step 2. Comparing SeSMiK-GE with unimodal T2w MRI, MRS classifiers and a commonly used feature concatenation (COD) strategy, yielded areas (AUC) under the receiver operative curve (ROC) of (a) 0.89±0.09 (SeSMiK), 0.54±0.18 (T2w MRI), 0.61±0.20 (MRS), and 0.64±0.23 (COD) for distinguishing benign from CaP regions, and (b) 0.84±0.07 (SeSMiK),0.54±0.13 (MRI), 0.59±0.19 (MRS), and 0.62±0.18 (COD) for distinguishing high and low grade CaP using a leave one out cross-validation strategy, all evaluations being performed on a per voxel basis. Our results suggest that following further rigorous validation, SeSMiK-GE could be developed into a powerful diagnostic and prognostic tool for detection and grading of CaP in vivo and in helping to determine the appropriate treatment option. Identifying low grade disease in vivo might allow CaP patients to opt for active surveillance rather than immediately opt for aggressive therapy such as radical prostatectomy. PMID:23294985

Tiwari, Pallavi; Kurhanewicz, John; Madabhushi, Anant

2013-02-01

175

Computer-aided detection in breast MRI: a systematic review and meta-analysis  

International Nuclear Information System (INIS)

To evaluate the additional value of computer-aided detection (CAD) in breast MRI by assessing radiologists' accuracy in discriminating benign from malignant breast lesions. A literature search was performed with inclusion of relevant studies using a commercially available CAD system with automatic colour mapping. Two independent researchers assessed the quality of the studies. The accuracy of the radiologists' performance with and without CAD was presented as pooled sensitivity and specificity. Of 587 articles, 10 met the inclusion criteria, all of good methodological quality. Experienced radiologists reached comparable pooled sensitivity and specificity before and after using CAD (sensitivity: without CAD: 89%; 95% CI: 78-94%, with CAD: 89%; 95%CI: 81-94%) (specificity: without CAD: 86%; 95% CI: 79-91%, with CAD: 82%; 95% CI: 76-87%). For residents the pooled sensitivity increased from 72% (95% CI: 62-81%) without CAD to 89% (95% CI: 80-94%) with CAD, however, not significantly. Concerning specificity, the results were similar (without CAD: 79%; 95% CI: 69-86%, with CAD: 78%; 95% CI: 69-84%). CAD in breast MRI has little influence on the sensitivity and specificity of experienced radiologists and therefore their interpretation remains essential. However, residents or inexperienced radiologists seem to benefit from CAD concerning breast MRI evaluation. (orig.)

2011-08-01

176

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)

2010-02-28

177

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.)

2014-01-01

178

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

Energy Technology Data Exchange (ETDEWEB)

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.)

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

179

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

Directory of Open Access Journals (Sweden)

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.

Y.Babykalpana

2011-04-01

180

[Detection of oculomotor nerve compression by 3D-FIESTA MRI in a patient with pituitary apoplexy and diabetes mellitus].  

Science.gov (United States)

We report the usefulness of 3D-FIESTA magnetic resonance imaging(MRI)for the detection of oculomotor nerve palsy in a case of pituitary apoplexy. A 69-year-old man with diabetes mellitus presented with complete left-side blepharoptosis. Computed tomography of the brain showed an intrasellar mass with hemorrhage. MRI demonstrated a pituitary adenoma with a cyst toward the left cavernous sinus, which was diagnosed as pituitary apoplexy. 3D-FIESTA revealed that the left oculomotor nerve was compressed by the cyst. He underwent trans-sphenoid tumor resection at 5 days after his hospitalization. Post-operative 3D-FIESTA MRI revealed decrease in compression of the left oculomotor nerve by the cyst. His left oculomotor palsy recovered completely within a few months. Oculomotor nerve palsy can occur due to various diseases, and 3D-FIESTA MRI is useful for detection of oculomotor nerve compression, especially in the field of parasellar lesions. PMID:24501187

Yamauchi, Takahiro; Kitai, Ryuhei; Neishi, Hiroyuki; Tsunetoshi, Kenzo; Matsuda, Ken; Arishima, Hidetaka; Kodera, Toshiaki; Arai, Yoshikazu; Takeuchi, Hiroaki; Kikuta, Ken-ichiro

2014-02-01

 
 
 
 
181

Generation and remote detection of THz sound using semiconductor superlattices  

CERN Document Server

The authors introduce a novel approach to study the propagation of high frequency acoustic phonons in which the generation and detection involves two spatially separated superlattices $\\sim 1 {\\rm \\mu m}$ apart. Propagating modes of frequencies up to $\\sim 1 {\\rm THz}$ escape from the superlattice where they are generated and reach the second superlattice where they are detected. The measured frequency spectrum reveals finite size effects, which can be accounted for by a continuum elastic model.

Trigo, M; Wahlstrand, J K; Merlin, R; Reason, M; Goldman, R S

2007-01-01

182

Detection of Spontaneous Schwannomas by MRI in a Transgenic Murine Model of Neurofibromatosis Type 21  

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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 P0 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 ...

Messerli, Sm; Tang, Y.; Giovannini, M.; Bronsonx, R.; Weissleder, R.; Breakefield, Xo

2002-01-01

183

3 TESLA PELVIC MRI AND MRS OF PELVIC ADNXEAL MASS FOR EARLY DETECTION OF OVARIAN CANCER  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Ovarian mass, which is identified in pelvic sonogram, TRVS or pelvic CT scan, sometimes has characteristics such as the border, shape, appearance and specific imaging findings for differentiating benign and malignant tumors. As we know if we can have early detection of ovarian cancer the 5-year-survival is 90% and stage 3 only has a 5-year-survival rate of 30%. MRI of the pelvis with complementary MRS of adnexal mass fluid increases the accuracy and specificity of criteria for early diagnosis...

Ahmad Soltani Shirazi

2012-01-01

184

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

1982-01-01

185

Regularisation in multi- and hyperspectral remote sensing change detection  

DEFF Research Database (Denmark)

Change detection methods for multi- and hypervariate data look for differences in data acquired over the same area at different points in time. These differences may be due to noise or differences in (atmospheric etc.) conditions at the two acquisition time points. To prevent a change detection method from detecting uninteresting change due to noise or arbitrary spurious differences the application of regularisation also known as penalisation is considered to be important. Two types of regularisation in change detected by the multivariate alteration detection (MAD) transformation are considered: 1) ridge regression type and smoothing operators applied to the estimated weights in the MAD transform; and 2) pre-processing (before applying the MAD transformation) by noise reducing orthogonal transformations where the number of retained transformed variables can be considered a regularisation parameter. Regularisation by the former methods smooth the weights given to the individual bands in the MAD transformation and thus it penalises weights that fluctuate wildly as a function of wavelength; regularisation by the latter methods tends to smooth in the image domain. Also, regularisation may be necessary to prevent numerical instability especially when working on hyperspectral data.

Nielsen, Allan Aasbjerg

2005-01-01

186

Diffusion-weighted and conventional MRI in detection of Multiple Sclerosis lesions in brain: a comparative study  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Multiple sclerosis (MS is a chronic disease that begins most commonly in young adults and is characterized pathologically by multiple areas of central nervous system (CNS white matter inflammation, demyelination, and glial scarring. The most valuable aid for diagnosis is magnetic resonance imaging (MRI. New type of MRI has been developed on the basis of molecular diffusion which capable of detecting acute and active lesions. Early diagnosis and treatment is possible to stop or slow down progression of disease. The aim of this study is to compare the findings of conventional and diffusion- weighted (DW MRI in detection cerebral lesions of MS. Methods: Thirty patients with clinically definite MS and 30 healthy volunteers were studied in a descriptive-prospective survey over a twelve-month period of time. Conventional and DW MRI were used in both groups. Total number, morphology, location and the mean size of the intra-cerebral plaques of MS were compared between group. The sensitivity and the specificity of both imaging methods in detecting these plaques were determined. Results: Thirty patients with MS with the mean age of 32.76±8.79 years and 30 healthy individuals with the mean age of 32.75± 9.23 years were enrolled. Plaque within the brain was significantly higher by the conventional method (P< 0.05. Ovoid lesions were greater in number in the conventional method group. More lesions were detected by the conventional method in the areas of periventricle, centrum semiovale and corpus callosum. Regarding the size of plaque, the minimum measurement was significantly lower in the conventional method group. The sensitivity of both methods was 100%. The specificity of conventional and DW MRI was 86.6% and 96.6%, respectively. Conclusion: In our study the sensitivity of both methods was the same but the specificity of DW MRI was higher. DW MRI may detect lesions which are not detectable by the routine methods.

"Z. Miabi

2006-07-01

187

Multimodal image registration of ex vivo 4 Tesla MRI with whole mount histology for prostate cancer detection  

Science.gov (United States)

In this paper we present novel methods for registration and subsequent evaluation of whole mount prostate histological sections to corresponding 4 Tesla ex vivo magnetic resonance imaging (MRI) slices to complement our existing computer-aided diagnosis (CAD) system for detection of prostatic adenocarcinoma from high resolution MRI. The CAD system is trained using voxels labeled as cancer on MRI by experts who visually aligned histology with MRI. To address voxel labeling errors on account of manual alignment and delineation, we have developed a registration method called combined feature ensemble mutual information (COFEMI) to automatically map spatial extent of prostate cancer from histology onto corresponding MRI for prostatectomy specimens. Our method improves over intensity-based similarity metrics (mutual information) by incorporating unique information from feature spaces that are relatively robust to intensity artifacts and which accentuate the structural details in the target and template images to be registered. Our registration algorithm accounts for linear gland deformations in the histological sections resulting from gland fixing and serial sectioning. Following automatic registration of MRI and histology, cancer extent from histological sections are mapped to the corresponding registered MRI slices. The manually delineated cancer areas on MRI obtained via manual alignment of histological sections and MRI are compared with corresponding cancer extent obtained via COFEMI by a novel registration evaluation technique based on use of non-linear dimensionality reduction (locally linear embedding (LLE)). The cancer map on MRI determined by COFEMI was found to be significantly more accurate compared to the manually determined cancer mask. The performance of COFEMI was also found to be superior compared to image intensity-based mutual information registration.

Chappelow, Jonathan; Madabhushi, Anant; Rosen, Mark; Tomaszeweski, John; Feldman, Michael

2007-03-01

188

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

189

Improved detection of localized prostate cancer using co-registered MRI and 11C-acetate PET/CT  

International Nuclear Information System (INIS)

Objectives: We aimed to study the ability of contrast enhanced MRI at 1.5 T and 11C-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 11C-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 11C-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.

2012-11-01

190

Detecting Weed Infestations in Soybean Using Remote Sensing.  

Science.gov (United States)

Can weed distribution maps be developed from remote sensed reflectance data? When are the appropriate times to collect these data during the season? What wavebands can be used to distinguish weedy from weed- free areas? This research examined if and when reflectance could be used to distinguish between weed-free and weed-infested (mixed species) areas in soybean and to determine the most useful wavebands to separate crop, weed, and soil reflectance differences. Treatments in the two-year study included no vegetation (bare soil), weed-free soybean, and weed-infested soybean and, in one year, 80% corn residue cover. Reflectance was measured at several sampling times from May through September in 2001 and 2002 using a hand-held multispectral radiometer equipped with band-limited optical interference filters (460 - 1650 nm). Pixel resolution was 0.8-m. Reflectance in the visible spectral range (460 to 700 nm) generally was similar among treatments. In the near-infrared (NIR) range (>700 to 1650 nm), differences among treatments were observed from soybean growth stage V-3 (about 4 weeks after planting) until mid-July to early August depending on crop vigor and canopy closure (76 cm row spacing in 2001 and 19 cm row spacing in 2002). Reflectance rankings in the NIR range when treatments could be differentiated were consistent between years and, from lowest to highest reflectance, were soil early stages of growth due to high reflectance from the residue and reduced weed numbers in these areas. These results suggest that NIR spectral reflectance collected prior to canopy closure can be used to distinguish weed-infested from weed-free areas.

Clay, S. A.; Chang, J.; Clay, D. E.; Dalsted, K.; Reese, C.

2007-12-01

191

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

2013-11-15

192

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2013-11-15

193

Detecting plant metabolic responses induced by ground shock using hyperspectral remote sensing and physiological contact measurements  

Energy Technology Data Exchange (ETDEWEB)

A series of field experiments were done to determine if ground shock could have induced physiological responses in plants and if the level of the response could be observed. The observation techniques were remote sensing techniques and direct contact physiological measurements developed by Carter for detecting pre-visual plant stress. The remote sensing technique was similar to that used by Pickles to detect what appeared to be ground shock induced plant stress above the 1993 Non Proliferation Experiment`s underground chemical explosion. The experiment was designed to provide direct plant physiological measurements and remote sensing ratio images and from the same plants at the same time. The simultaneous direct and remote sensing measurements were done to establish a ground truth dataset to compare to the results of the hyperspectral remote sensing measurements. In addition, the experiment was designed to include data on what was thought to be the most probable interfering effect, dehydration. The experimental design included investigating the relative magnitude of the shock induced stress effects compared to dehydration effects.

Pickles, W.L.; Cater, G.A.

1996-12-03

194

A comprehensive segmentation, registration, and cancer detection scheme on 3 Tesla in vivo prostate DCE-MRI.  

Science.gov (United States)

Recently, high resolution 3 Tesla (T) Dynamic Contrast-Enhanced MRI (DCE-MRI) of the prostate has emerged as a promising modality for detecting prostate cancer (CaP). Computer-aided diagnosis (CAD) schemes for DCE-MRI data have thus far been primarily developed for breast cancer and typically involve model fitting of dynamic intensity changes as a function of contrast agent uptake by the lesion. Comparatively there is relatively little work in developing CAD schemes for prostate DCE-MRI. In this paper, we present a novel unsupervised detection scheme for CaP from 3 T DCE-MRI which comprises 3 distinct steps. First, a multi-attribute active shape model is used to automatically segment the prostate boundary from 3 T in vivo MR imagery. A robust multimodal registration scheme is then used to non-linearly align corresponding whole mount histological and DCE-MRI sections from prostatectomy specimens to determine the spatial extent of CaP. Non-linear dimensionality reduction schemes such as locally linear embedding (LLE) have been previously shown to be useful in projecting such high dimensional biomedical data into a lower dimensional subspace while preserving the non-linear geometry of the data manifold. DCE-MRI data is embedded via LLE and then classified via unsupervised consensus clustering to identify distinct classes. Quantitative evaluation on 21 histology-MRI slice pairs against registered CaP ground truth estimates yielded a maximum CaP detection accuracy of 77.20% while the popular three time point (3TP) scheme yielded an accuracy of 67.37%. PMID:18979803

Viswanath, Satish; Bloch, B Nicolas; Genega, Elisabeth; Rofsky, Neil; Lenkinski, Robert; Chappelow, Jonathan; Toth, Robert; Madabhushi, Anant

2008-01-01

195

Spectral Clustering on Neighborhood Kernels with Modified Symmetry for Remote Homology Detection  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Remote homology detection among proteins in an unsupervised approach from sequences is an important problem in computational biology. The existing neighborhood cluster kernel methods and Markov clustering algorithms are most efficient for homolog detection. Yet they deviate from random walks with inflation or similarity depending on hard thresholds. Our spectral clustering approach with new combined local alignment kernels more effectively exploits state-of-the-art neighborhood vectors global...

Sarkar, Anasua; Nikolski, Macha; Maulik, Ujjwal

2011-01-01

196

Multifunctional fiber-optic microwave links based on remote heterodyne detection  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Gliese, Ulrik Bo; Nielsen, Torben Nřrskov; Nielsen, Sřren Nřrskov; Stubkjćr, Kristian

2006-01-01

197

Remote sensing to detect ecological impacts associated with acid deposition. Final report  

Energy Technology Data Exchange (ETDEWEB)

A planning study was conducted to determine the potential applications of remote sensing for detecting ecological impacts that have been reportedly caused by acid deposition. The project was divided into two phases: a technology assessment phase (Phase I) and a prototype demonstration (Phase II). The emphasis of the project was on detecting ecological change, not on determining the cause of that change. The latter is the role of ground-based research. Phase I consisted of an assessment of terrestrial and aquatic components that are indicative of sensitivity to acid deposition. The assessment identified remote sensing as the optimal cost-effective method for measuring the rate of change of land use, crop type, and forest canopy health over large geographic areas. In Phase II, spectral reflectance in the near-infrared region of the spectrum from forest canopies of Camel's Hump State Forest from two Landsat scenes from the summers of 1976 and 1983 were compared. Significant increases in spectral reflectance from the forest were detected when the pixels were compared, and it is hypothesized that this increase is indicative of a decline in forest growth and canopy closure. However, because of project limitations, no ground-truth data were collected by Battelle-Northwest scientists to verify the findings of the remote sensing analyses. A comprehensive research program is recommended to further investigate the use of remote sensing to detect ecological damage and its relationship to possible causative agents. Future research should also focus on the use of remote sensing for identifying ecosystems that may be sensitive to perturbations like acid deposition and improving our ability to model ecological processes. Priority should be given to detecting, monitoring, and modeling changes in forested watersheds.

Van Voris, P.; Wukelic, G.E.

1986-05-01

198

Automatic multiple sclerosis lesion detection in brain MRI by FLAIR thresholding.  

Science.gov (United States)

Magnetic resonance imaging (MRI) is frequently used to detect and segment multiple sclerosis lesions due to the detailed and rich information provided. We present a modified expectation-maximisation algorithm to segment brain tissues (white matter, grey matter, and cerebro-spinal fluid) as well as a partial volume class containing fluid and grey matter. This algorithm provides an initial segmentation in which lesions are not separated from tissue, thus a second step is needed to find them. This second step involves the thresholding of the FLAIR image, followed by a regionwise refinement to discard false detections. To evaluate the proposal, we used a database with 45 cases comprising 1.5T imaging data from three different hospitals with different scanner machines and with a variable lesion load per case. The results for our database point out to a higher accuracy when compared to two of the best state-of-the-art approaches. PMID:24813718

Cabezas, Mariano; Oliver, Arnau; Roura, Eloy; Freixenet, Jordi; Vilanova, Joan C; Ramió-Torrentŕ, Lluís; Rovira, Alex; Lladó, Xavier

2014-07-01

199

Time-of-flight flow imaging using NMR remote detection  

Energy Technology Data Exchange (ETDEWEB)

A time-of-flight imaging technique is introduced to visualize fluid flow and dispersion through porous media using NMR. As the fluid flows through a sample, the nuclear spin magnetization is modulated by RF pulses and magnetic field gradients to encode the spatial coordinates of the fluid. When the fluid leaves the sample, its magnetization is recorded by a second RF coil. This scheme not only facilitates a time-dependent imaging of fluid flow, it also allows a separate optimization of encoding and detection subsystems to enhance overall sensitivity. The technique is demonstrated by imaging gas flow through a porous rock.

Granwehr, Josef; Harel, Elad; Han, Song-I; Garcia, Sandra; Pines,Alex; Sen, Pabitra N.; Song, Yi-Qiao

2005-05-05

200

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

Energy Technology Data Exchange (ETDEWEB)

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.)

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

 
 
 
 
201

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.)

2007-11-01

202

Configurable Automatic Detection and Registration of Fiducial Frames for Device-to-Image Registration in MRI-guided Prostate Interventions  

Science.gov (United States)

We propose a novel automatic fiducial frame detection and registration method for device-to-image registration in MRI-guided prostate interventions. The proposed method does not require any manual selection of markers, and can be applied to a variety of fiducial frames, which consist of multiple cylindrical MR-visible markers placed in different orientations. The key idea is that automatic extraction of linear features using a line filter is more robust than that of bright spots by thresholding; by applying a line set registration algorithm to the detected markers, the frame can be registered to the MRI. The method was capable of registering the fiducial frame to the MRI with an accuracy of 1.00 ± 0.73 mm and 1.41 ± 1.06 degrees in a phantom study, and was sufficiently robust to detect the fiducial frame in 98% of images acquired in clinical cases despite the existence of anatomical structures in the field of view.

Tokuda, Junichi; Song, Sang-Eun; Tuncali, Kemal; Tempany, Clare; Hata, Nobuhiko

2014-01-01

203

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

Directory of Open Access Journals (Sweden)

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%.

S.M.M. Kahaki

2012-09-01

204

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

Energy Technology Data Exchange (ETDEWEB)

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.

Jerry Myers

2005-04-15

205

3T MRI relaxometry detects T2 prolongation in the cerebral normal-appearing white matter in multiple sclerosis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

MRI at 3 T has increased sensitivity in detecting overt multiple sclerosis (MS) brain lesions; a growing body of data suggests clinically relevant damage occurs in the normal-appearing white matter (NAWM). We tested a novel pulse sequence to determine whether 3 T MRI spin–spin relaxometry detected damage in NAWM of MS patients (n = 13) vs. age-matched normal controls [(NL) (n = 11)]. Baseline characteristics of the MS group were: age (mean ± SD) 42.5 ± 5.4 (range 33–51 years), disease d...

2009-01-01

206

Detecting Patterns of a Technological Intelligence in Remotely Sensed Imagery  

Science.gov (United States)

A statistical classification approach for detecting artificial patterns in satellite imagery such as those produced by a technological intelligence, and its application to the search for non-natural features of possible extraterrestrial origin on planetary surfaces is presented. Statistics of natural terrestrial backgrounds (fractal textures, drainage patterns, tectonic features, etc.) and artificial features (e.g., roads, cities, vehicles, archaeological ruins) are computed over a set of terrestrial training images. Images are represented by measurements of their fractal dimension, fractal model fit, anisotropy, and rectilinearity. The likelihood ratio (conditional probability of a measurement given it is artificial divided by the conditional probability of a measurement given it is natural) is used as an index for assessing the artificiality of an unknown image relative to the training set. A classification accuracy of 85% is achieved over a training set of terrestrial images. The statistics of the training set are then extended to assess a number of enigmatic lunar and planetary features. Results suggest that certain areas on our moon and on Mars appear to be artificial by comparison with terrestrial features.

Carlotto, M. J.

207

The remote detection of uranium leaks using fluorescence characteristics  

International Nuclear Information System (INIS)

This thesis will describe the work undertaken to design and construct a prototype uranium leak detector for use in the nuclear industry. Uranium has a very distinctive fluorescence signature with a much longer fluorescence lifetime than typical fluorescing materials. Conventional fluorescence has a lifetime of around 10-8 s whereas the lifetime of uranium fluorescence has been recorded at between 10 and 100 ?s. The detector is calibrated to search solely for the distinctive uranium fluorescence. Care was taken to ensure that phosphorescent materials with a similar lifetime would not interfere with the uranium signal. Typically uranium fluorescence is induced using high power ultra-violet lasers, usually nitrogen lasers operating at 337 nm, but such equipment is expensive and bulky. In addition, the detection of the fluorescence signal typically uses photomultiplier tubes or cooled photodiode arrays which are again expensive. The CASE award supervisors at BNFL had expressed a desire for the cost of the prototype to be kept to a minimum and for this reason alternative sources and detectors were investigated. The apparatus is controlled using an IBM compatible PC and is set up to continually search an area for the uranium fluorescence signal. On finding tile uranium fluorescence its location is calculated using triangulation methods and tile alarm is raised. (author)

1999-01-01

208

Detection of thrombus size and protein content by ex vivo magnetization transfer and diffusion weighted MRI  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background To utilize a rabbit model of plaque disruption to assess the accuracy of different magnetic resonance sequences [T1-weighted (T1W, T2-weighted (T2W, magnetization transfer (MT and diffusion weighting (DW] at 11.7?T for the ex vivo detection of size and composition of thrombus associated with disrupted plaques. Methods Atherosclerosis was induced in the aorta of male New Zealand White rabbits (n?=?17 by endothelial denudation and high-cholesterol diet. Subsequently, plaque disruption was induced by pharmacological triggering. Segments of infra-renal aorta were excised fixed in formalin and examined by ex vivo magnetic resonance imaging (MRI at 11.7?T and histology. Results MRI at 11.7?T showed that: (i magnetization transfer contrast (MTC and diffusion weighted images (DWI detected thrombus with higher sensitivity compared to T1W and T2W images [sensitivity: MTC?=?88.2%, DWI?=?76.5%, T1W?=?66.6% and T2W?=?43.7%, P?P?(ii MTC and DWI provided a more accurate detection of thrombus area with histology as the gold-standard [underestimation of 6% (MTC and 17.6% (DWI compared to an overestimation of thrombus area of 53.7% and 46.4% on T1W and T2W images, respectively]; (iii the percent magnetization transfer rate (MTR correlated with the fibrin (r?=?0.73, P?=?0.003 and collagen (r?=?0.9, P?=?0.004 content of the thrombus. Conclusions The conspicuity of the thrombus was increased on MTC and DW compared to T1W and T2W images. Changes in the %MTR and apparent diffusion coefficient can be used to identify the organization stage of the thrombus.

Phinikaridou Alkystis

2012-06-01

209

Voxel-based analysis of MRI detects abnormal visual cortex in children and adults with amblyopia.  

Science.gov (United States)

Amblyopia, sometimes called "lazy eye," is a relatively common developmental visual disorder well characterized behaviorally; however, the neural substrates associated with amblyopia in humans remain unclear. We hypothesized that abnormalities in the cerebral cortex of subjects with amblyopia exist, possibly as a result of experience-dependent neuronal plasticity. Anatomic magnetic resonance imaging (MRI) and psychophysical vision testing was carried out on 74 subjects divided into two age ranges, 7-12 years and 18-35 years, and three diagnoses, strabismic amblyopia, anisometropic amblyopia, and normal vision. We report a behavioral impairment in contrast sensitivity for subjects with amblyopia, consistent with previous reports. When the high-resolution MRI brain images were analyzed quantitatively with optimized voxel-based morphometry, results indicated that adults and children with amblyopia have decreased gray matter volume in visual cortical regions, including the calcarine sulcus, known to contain primary visual cortex. This finding was confirmed with a separate region-of-interest analysis. For the children with amblyopia, additional gray matter reductions in parietal-occipital areas and ventral temporal cortex were detected, consistent with recent reports that amblyopia can result in spatial location and object processing deficits. These data are the first to provide possible neuroanatomic bases for the loss of binocularity and visual sensitivity in children and adults with amblyopia. PMID:15846772

Mendola, Janine D; Conner, Ian P; Roy, Anjali; Chan, Suk-Tak; Schwartz, Terry L; Odom, J Vernon; Kwong, Kenneth K

2005-06-01

210

Computer-aided detection (CAD) for breast MRI: evaluation of efficacy at 3.0 T  

Energy Technology Data Exchange (ETDEWEB)

The purpose of the study was to evaluate the accuracy of 3.0-T breast MRI interpretation using manual and fully automated kinetic analyses. Manual MRI interpretation was done on an Advantage Workstation. Retrospectively, all examinations were processed with a computer-aided detection (CAD) system. CAD data sets were interpreted by two experienced breast radiologists and two residents. For each lesion automated analysis of enhancement kinetics was evaluated at 50% and 100% thresholds. Forty-nine malignant and 22 benign lesions were evaluated. Using threshold enhancement alone, the sensitivity and specificity of CAD were 97.9% and 86.4%, respectively, for the 50% threshold, and 97.9% and 90%, respectively, for the 100% threshold. Manual interpretation by two breast radiologists showed a sensitivity of 84.6% and a specificity of 68.8%. For the same two radiologists the mean sensitivity and specificity for CAD-based interpretation was 90.4% (not significant) and 81.3% (significant at p < 0.05), respectively. With one-way ANOVA no significant differences were found between the two breast radiologists and the two residents together, or between any two readers separately. CAD-based analysis improved the specificity compared with manual analysis of enhancement. Automated analysis at 50% and 100% thresholds showed a high sensitivity and specificity for readers with varying levels of experience. (orig.)

Meeuwis, Carla [Rijnstate Hospital, Department of Radiology, Alysis Zorggroep, Arnhem (Netherlands); Ven, Stephanie M. van de [Stanford University, Department of Radiology, Stanford, CA (United States); Stapper, Gerard; Fernandez Gallardo, Arancha M.; Bosch, Maurice A.A.J. van den; Mali, Willem P.T.M.; Veldhuis, Wouter B. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands)

2010-03-15

211

Automatic Cloud Detection and Removal Algorithm for MODIS Remote Sensing Imagery  

Directory of Open Access Journals (Sweden)

Full Text Available 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 cloud, an automatic algorithm of cloud detection and removal is proposed in this paper. Firstly, several necessary preprocessing works need to be done for MODIS L1B data, including geometric precision correction, bowtie effect elimination and stripe noise removal. Furthermore, through analyzing the cloud spectral characters derived from the thirty-six bands of MODIS data, it can be found the spectral reflections of ground and cloud are different in various MODIS bands. Hence, cloud and ground can be respectively identified based on the analysis of multispectral characters derived from MODIS imagery. Cloud removal processing mainly aims at cloud region rather than whole image, which can improve processing efficiency. As for thin cloud and thick cloud regions, the corresponding cloud removal algorithms are proposed in this paper. Experimental results demonstrate that the proposed algorithms can effectively detect and remove cloud from MODIS imagery, which can meet the demands of post-processing of remote sensing imagery.

Shuang Zhang

2011-07-01

212

Detection and surveillance of rejection reactions after heart transplant by means of a sequence of MRI of 'black blood' type  

International Nuclear Information System (INIS)

A echocardiography and a MRI (Magnetic Resonance Imaging) investigation were achieved at 3 months to 7 years after heart transplant in 61 patients among whose 35 were suspected of rejection and 32 have had a myocardial biopsy. The myocardial (T2) transversal relaxation time was determined by using an inversion-recovery/spin-echo upon a magnet of 0.5 T. The rejection diagnosis criteria by echography was compared with that of a anomalistic high value of T2: 1. the MRI was positive but the echography not in 5 cases, all having positive biopsies; 2. the echography was positive but the MRI was not in 10 cases among which all the biopsies were negative; 3. the MRI and the echography gave concordant results in 46 cases (7 positives and 39 negatives) among which an agreement with the biopsy results was observed in 91% (20/22) of cases. The 12 patients having a positive MRI have had a new examination at 2 to 15 days after the anti-rejection treatment; the T2 values got normalized. In conclusion, the determination of the myocardial T2 by means of a 'black blood' MRI sequence appears to be superior to an echocardiography in detecting the rejections after heart transplant and could be utilised to evaluate the efficiency of anti-rejection treatment

1997-10-01

213

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2005-01-01

214

Building Extraction and Change Detection in Multitemporal Remotely Sensed Images with Multiple Birth and Death Dynamics  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper we introduce a new probabilistic method which integrates building extraction with change detection in remotely sensed image pairs. A global optimization process attempts to find the optimal configuration of buildings, considering the observed data, prior knowledge, and interactions between the neighboring building parts. The accuracy is ensured by a Bayesian object model verification, meanwhile the computational cost is significantly decreased by a non-uniform stochastic object ...

Benedek, Csaba; Descombes, Xavier; Zerubia, Josiane

2009-01-01

215

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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-Stokes' equation for a sinking sphere at Reynolds numbers typical of marine snow (up to 20). Fluid deformation rate, the component of the flow that can be perceived by copepods, attenuates rapidly, and...

Kiřrboe, Thomas; Thygesen, Uffe Hřgsbro

2008-01-01

216

Remote thermal IR surveying to detect abandoned mineshafts in former mining areas  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In former mining areas it is critical to locate unknown, abandoned mineshafts prior to the development of a site. Abandoned mineshafts are ground disturbances that have very localized effects on the morphology and the physical, chemical, drainage and moisture properties of the surface geological materials and thus thermo-physical properties. Remotely sensed thermal IR surveys provide the potential for a rapid, inexpensive and non-intrusive technique for mineshaft detection. The key parameters...

2008-01-01

217

A comparison of profile hidden Markov model procedures for remote homology detection  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Profile hidden Markov models (HMMs) are amongst the most successful procedures for detecting remote homology between proteins. There are two popular profile HMM programs, HMMER and SAM. Little is known about their performance relative to each other and to the recently improved version of PSI-BLAST. Here we compare the two programs to each other and to non-HMM methods, to determine their relative performance and the features that are important for their success. The quality of the multiple seq...

Madera, Martin; Gough, Julian

2002-01-01

218

The inferior colliculus is involved in deviant sound detection as revealed by BOLD fMRI.  

Science.gov (United States)

Rapid detection of deviant sounds is a crucial property of the auditory system because it increases the saliency of biologically important, unexpected sounds. The oddball paradigm in which a deviant sound is randomly interspersed among a train of standard sounds has been traditionally used to study this property in mammals. Currently, most human studies have only revealed the involvement of cortical regions in this property. Recently, several animal electrophysiological studies have reported that neurons in the inferior colliculus (IC) exhibit reduced responses to a standard sound but restore their responses at the occurrence of a deviant sound (i.e., stimulus-specific adaptation or SSA), suggesting that the IC may also be involved in deviance detection. However, by adopting an invasive method, these animal studies examined only a limited number of neurons. Although SSA appears to be more prominent in the external cortical nuclei of the IC for frequency deviant, a thorough investigation of this property throughout the IC using other deviants and efficient imaging techniques may provide more comprehensive information on this important phenomenon. In this study, blood-oxygen-level-dependent (BOLD) fMRI with a large field of view was applied to investigate the role of the IC in deviance detection. Two sound tokens that had identical frequency spectrum but temporally inverted profiles were used as the deviant and standard. A control experiment showed that these two sounds evoked the same responses in the IC when they were separately presented. Two oddball experiments showed that the deviant induced higher responses than the standard (by 0.41±0.09% and 0.41±0.10%, respectively). The most activated voxels were in the medial side of the IC in both oddball experiments. The results clearly demonstrated that the IC is involved in deviance detection. BOLD fMRI detection of increased activities in the medial side of the IC to the deviant revealed the highly adaptive nature of a substantial population of neurons in this region, probably those that belong to the rostral or dorsal cortex of the IC. These findings highlighted the complexity of auditory information processing in the IC and may guide future studies of the functional organizations of this subcortical structure. PMID:24486979

Gao, Patrick P; Zhang, Jevin W; Cheng, Joe S; Zhou, Iris Y; Wu, Ed X

2014-05-01

219

Continuously moving table MRI with sliding multislice for rectal cancer staging: Image quality and lesion detection  

International Nuclear Information System (INIS)

Purpose: To determine image quality and lesion detection of sliding multislice (SMS), a recently developed moving table MRI technique, in patients with rectal cancer. Materials and methods: Twenty-seven paired SMS (Avanto, Siemens Medical Solutions) and MDCT (Sensation 64, Siemens Medical Solutions) examinations of abdomen and pelvis were performed in patients with rectal cancer and compared for detection of liver, lymph node and bone metastases by two independent observers. A contrast-enhanced, fat saturated 2D gradient echo sequence (TE, 2.0 ms; TR, 102 ms; slice, 5 mm) was acquired with SMS and a standard contrast-enhanced protocol (100 ml 2.5 ml/s; slice, 5 mm) was used for abdominal MDCT. Standard of reference consisted of a consensus evaluation of SMS, MDCT, and all available follow-up examinations after a period of 6 months. Artifact burden and image quality of SMS was assessed in comparison to stationary gradient echo sequences obtained in an age-matched group of 27 patients. Results: Whereas SMS achieved a mean quality score of 3.65 (scale, 0-4) for the liver, representing very good diagnostic properties, strong breathing artifacts in the intestinal region were observed in 19 cases by both observers. The retroperitoneum still achieved a mean quality score of 3.52, although breathing artifacts were noted in 12 and 15 cases (observers 1 and 2, respectively). The sensitivities of SMS to detect hepatic metastases were 91.2% and 94.1% for both observers, respectively, compared to 98.5%/98.5% for MDCT. The sensitivities for lymph node metastases were 87.5%/81.3% for SMS compared to 78.1%/81.3% for MDCT. The sensitivities for bone metastases were 91.7%/100% for SMS compared to 8.3%/16.7% for MDCT. Conclusion: With slightly reduced image quality in the intestinal region, SMS exhibits equal detection of lymph node and liver metastases compared to MDCT. SMS MRI proved to be superior to MDCT in detection of bone metastases.

2010-03-01

220

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

International Nuclear Information System (INIS)

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.)

2011-11-01

 
 
 
 
221

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

Energy Technology Data Exchange (ETDEWEB)

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.)

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

222

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

Energy Technology Data Exchange (ETDEWEB)

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.)

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

223

Initial studies on the remote detection of submerged Orimulsion with a range-gated laser fluorosensor  

International Nuclear Information System (INIS)

Tests are being conducted to determine the capabilities of active sensors such as the laser fluorosensor used to detect heavy oils under the water surface. Submerged and neutrally buoyant oils and other petroleum products such as Orimulsion are very difficult to detect using conventional sensors. Environment Canada and the Canadian Coast Guard have initiated a series of studies to develop technologies capable of real-time remote detection of submerged spills in the marine environment. This paper presented the preliminary results of remote detection testing of submerged Orimulsion with laser-induced fluorescence. Laser fluorosensors are airborne sensors used to detect, classify and map oils and other petroleum products in both marine and terrestrial environments. Modern laser fluorosensors have range-gated detection systems which turn on the detector at the exact moment when a fluorescence spectral return is expected. The detector can be range-gated to look into the water column to observe fluorescence emitted from a submerged target. The clarity of the water and the emission of the wavelength from the laser determine the depth to which the technique can be used. Overlying water changes the fluorescence signature of the submerged target due to wavelength-dependent absorption. 15 refs., 2 tabs., 5 figs

2002-06-11

224

An investigation of the white matter microstructure in motion detection using diffusion MRI.  

Science.gov (United States)

One of the most widely investigated functions of the brain is vision. Whereas special attention is often paid to motion detection and its modulation by attention, comparatively still little is known about the structural background of this function. We therefore, examined the white matter microstructural background of coherent motion detection. A random-dot kinematogram paradigm was used to measure the sensitivity of healthy individuals? to movement coherence. The potential correlation was investigated between the motion detection threshold and the white matter microstructure as measured by high angular resolution diffusion MRI. The Track Based Spatial Statistics method was used to address this correlation and probabilistic tractography to reveal the connection between identified regions. A significant positive correlation was found between the behavioural data and the local fractional anisotropy in the posterior part of the right superior frontal gyrus, the right juxta-cortical superior parietal lobule, the left parietal white matter, the left superior temporal gyrus and the left optic radiation. Probabilistic tractography identified pathways that are highly similar to the segregated attention networks, which have a crucial role in the paradigm. This study draws attention to the structural determinant of a behavioural function. PMID:24833063

Csete, Gerg?; Szabó, Nikoletta; Rokszin, Alice; Tóth, Eszter; Braunitzer, Gábor; Benedek, György; Vécsei, László; Kincses, Zsigmond Tamás

2014-06-27

225

MRI to detect atherosclerosis with gadolinium-containing immunomicelles targeting the macrophage scavenger receptor.  

Science.gov (United States)

The ability to specifically image macrophages may enable improved detection and characterization of atherosclerosis. In this study we evaluated the in vitro uptake of gadolinium (Gd)-containing immunomicelles (micelles linked to macrophage-specific antibody), micelles, and standard contrast agents by murine macrophages, and sought to determine whether immunomicelles and micelles improve ex vivo imaging of apolipoprotein E knockout (ApoE KO) murine atherosclerosis. Murine RAW 264.7 macrophages were incubated with Gd-DTPA, micelles, and immunomicelles. Cell pellets were prepared and imaged using a 1.5 T MR system with an inversion recovery spin-echo sequence to determine the in vitro T1 values. Ex vivo analysis of mouse aortas was performed using a 9.4T MR system with a high-spatial-resolution sequence (78x39x78 microm3). The T1 value was significantly decreased in cells treated with micelles compared to Gd-DTPA (P<0.0001), and in cells incubated at 4 degrees C with immunomicelles compared to micelles (P<0.05). Ex vivo MRI signal intensity (SI) was significantly increased by 81% and 20% in aortas incubated with immunomicelles and micelles, respectively. Confocal microscopy demonstrated in vitro and ex vivo uptake of fluorescent immunomicelles by macrophages. Immunomicelles and micelles improve in vitro and ex vivo MR detection of macrophages, and may prove useful in the detection of macrophage-rich plaques. PMID:16902977

Lipinski, Michael J; Amirbekian, Vardan; Frias, Juan C; Aguinaldo, Juan Gilberto S; Mani, Venkatesh; Briley-Saebo, Karen C; Fuster, Valentin; Fallon, John T; Fisher, Edward A; Fayad, Zahi A

2006-09-01

226

Development of CAD System Based on Enhanced Clustering Based Segmentation Algorithm for Detection of Masses in Breast DCE-MRI  

Directory of Open Access Journals (Sweden)

Full Text Available Breast cancer continues to be a significant public health problem in the world. Early detection is the key for improving breast cancer prognosis. Mammography is currently the primary method of early detection. But recent research has shown that many cases missed by mammography can be detected in Breast DCE-MRI. Magnetic Resonance (MR imaging is emerging as the most sensitive modality that is currently available for the detection of primary or recurrent breast cancer. Breast DCE-MRI is more effective than mammography, because it generates much more data. Magnetic resonance imaging (MRI is emerging as a powerful tool for the diagnosis of breast abnormalities. Computer Aided Detection (CAD is of great help to this situation and image segmentation is most important process of computer Aided Detection, Magnetic Resonance Imaging data are a major challenge to any image processing software because of the huge amount of image voxels. Automatic approaches to breast cancer detection can help radiologists in this hard task and speed up the inspection process. To segment the mass of the breast region from 3D MRI set, a multistage image processing procedure was proposed. Data acquisition, processing and visualization techniques facilitate diagnosis. Image segmentation is an established necessity for an improved analysis of Magnetic Resonance (MR images. Segmentation from MR images may aid in tumor treatment by tracking the progress of tumor growth and shrinkage. The advantages of Magnetic Resonance Imaging are that the spatial resolution is high and provides detailed images. The tumor segmentation in Breast MRI image is difficult due to the complicated galactophore structure. The work in this paper attempts to accurately segment the abnormal breast mass in DCE-MRI Images. The mass is segmented using a novel clustering algorithm based on unsupervised segmentation, through neural network techniques, of an optimized space in which to perform clustering. The effectiveness of the proposed technique is determined by the extent to which potential abnormalities can be extracted from corresponding breast MRI based on its analysis, this algorithm also proposes changes that could reduce this error, and help to give good results all around. Tests performed on both real and simulated MR images shows good result.

D. Janaki Sathya

2011-09-01

227

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

DEFF Research Database (Denmark)

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.

Hougaard, K D; Hjort, N

2013-01-01

228

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

Science.gov (United States)

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.

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

2012-07-01

229

Monitoring Forests: A New Paradigm of Remote Sensing & GIS Based Change Detection  

Directory of Open Access Journals (Sweden)

Full Text Available Remote sensing has emerged as the main tool for mapping and monitoring of forest resources globally. In India, this technological tool is in use for biennial monitoring of forest cover of the country for the last 25 years. Among the numerous applications of remote sensing in forest management, change detection is the one which is most frequently used. In this paper, a new paradigm of change detection has been presented in which change of vegetation in a grid (a square shaped unit area is the basis of change analysis instead of change at the pixel level. The new method is a simpler approach and offers several advantages over the conventional approaches of remote sensing based change detection. The study introduces an index termed as ‘Grid Vegetation Change Index (GVCI’, its numerical value gives quantified assessment of the degree of change. The minus value of GVCI indicates loss or negative change and similarly positive value vice versa. By applying the GVCI on a pair of remotely sensed images of two dates of an area, one can know degree of vegetation change in every unit area (grid of the large landscape. Based on the GVCI values, one can select those grids which show significant changes. Such ‘candidate grids with significant changes’ may be shortlisted for ground verification and studying the causes of change. Since the change identification is based on the index value, it is free from human subjectivity or bias. Though there may be some limitations of the methodology, the GVCI based approach offers an operational application for monitoring forests in India and elsewhere for complete scanning of forest areas to pointedly identify change locations, identifying the grids with significant changes for objective and discrete field inspections with the help of GPS. It also offers a method to monitor progress of afforestation and conservation schemes, monitor habitats of wildlife areas and potential application in carbon assessment methodologies of CDM and REDD+.

Subhash Ashutosh

2012-11-01

230

Edge Detection from High Resolution Remote Sensing Images using Two-Dimensional log Gabor Filter in Frequency Domain  

Science.gov (United States)

Edges are vital features to describe the structural information of images, especially high spatial resolution remote sensing images. Edge features can be used to define the boundaries between different ground objects in high spatial resolution remote sensing images. Thus edge detection is important in the remote sensing image processing. Even though many different edge detection algorithms have been proposed, it is difficult to extract the edge features from high spatial resolution remote sensing image including complex ground objects. This paper introduces a novel method to detect edges from the high spatial resolution remote sensing image based on frequency domain. Firstly, the high spatial resolution remote sensing images are Fourier transformed to obtain the magnitude spectrum image (frequency image) by FFT. Then, the frequency spectrum is analyzed by using the radius and angle sampling. Finally, two-dimensional log Gabor filter with optimal parameters is designed according to the result of spectrum analysis. Finally, dot product between the result of Fourier transform and the log Gabor filter is inverse Fourier transformed to obtain the detections. The experimental result shows that the proposed algorithm can detect edge features from the high resolution remote sensing image commendably.

Wang, K.; Yu, T.; Meng, Q. Y.; Wang, G. K.; Li, S. P.; Liu, S. H.

2014-03-01

231

Memory for familiar environments learned in the remote past: fMRI studies of healthy people and an amnesic person with extensive bilateral hippocampal lesions.  

Science.gov (United States)

Preserved remote spatial memory in amnesic people with bilateral hippocampal damage, including the well-studied case K.C., challenges spatial theories, which assume that the hippocampus is needed to support all allocentric spatial representations, old or new. It remains possible, however, that residual hippocampal tissue is functional and contributes to successful performance. Here, we examine brain activity with fMRI during the retrieval of spatial information in K.C. and in healthy controls using landmark and route stimuli from a premorbidly familiar neighborhood that K.C. can navigate normally. In all participants, activity was found in the parahippocampal cortex, but not in the hippocampus itself, during all navigational tasks on which K.C. performs well, even though part of his hippocampus remains viable. The opposite pattern was observed on a house recognition task, which is inconsequential to navigation, and on which K.C. performed poorly. On that task, K.C. recruited the right hippocampus presumably because even "familiar" houses were treated as novel by him, whereas controls recruited occipitotemporal cortex, including parahippocampal cortex. The distinction between recent and remote memory, therefore, may apply as much to spatial theories of hippocampal function as it does to theories emphasizing the role of the hippocampus in other types of explicit memory. PMID:17853413

Rosenbaum, R Shayna; Winocur, Gordon; Grady, Cheryl L; Ziegler, Marilyne; Moscovitch, Morris

2007-01-01

232

Detecting functional connectivity change points for single-subject fMRI data  

Directory of Open Access Journals (Sweden)

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.

IvorCribben

2013-10-01

233

Limits of passive remote detection of hazardous vapors by computer simulation  

Science.gov (United States)

Passive infrared is an emerging method for the remote detection of hazardous vapors particularly where warning is the primary consideration. Detection of gases, vapors and aerosols is based on the difference, (Delta) T), between the temperature of the target cloud and the effective radiometric temperature of the background. Computer simulation of spectra has been used to predict the detection limits for several target gases with a low angle sky background. The simulation is based on a 3 layer model that uses MODTRAN, which includes 6 standard atmospheric models, to compute background radiance and atmospheric transmittance. The detection limits, at 2 cm-1 resolution, for sulfur hexafluoride (simulant), Sarin, trichlorethylene, methyl isocyanate (the Bhopal gas), mustard gas, methyl chloride, and sulfur dioxide are discussed for selected cases with the U.S. Standard, and the sub-arctic winter and the tropical models. In this paper the method is illustrated with methyl isocyanate.

Flanigan, Dennis F.

1996-06-01

234

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

Directory of Open Access Journals (Sweden)

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.

"A. Mirzajani

2005-08-01

235

Detectability of Her2 positive tumors using monoclonal antibody conjugated iron oxide nanoparticles in MRI.  

Science.gov (United States)

Detecting an imaging signal from a small number of cells is vital when a disease needs to be diagnosed in an early stage of development. Molecular and genetic information from cancer cell types provide a guide for specific imaging based on gene expression and their activities on the cell membrane. Various physical and biological parameters affect the capability of an imaging system to provide an efficient procedure for biomarker imaging. Iron oxide based magnetic nanoparticles conjugated to breast cancer monoclonal antibody (Her2) were used as a specific contrast agent for detection of the tumor cells in nude mice models. All processes for the nanoparticle synthesis, antibody development, and conjugation strategies were designed and evaluated in the current work. The final engineered product was found to be without precipitate containing 20 microg antibody/mg magnetic nanoparticles at 10 mg Fe/ml solution. This contrast agent has a high affinity for the BT474 breast cancer cells. MRI images of nude mice bearing tumor cells confirm this specific biomarker based imaging protocol. PMID:21770186

Oghabian, M A; Jeddi-Tehrani, M; Zolfaghari, A; Shamsipour, F; Khoei, S; Amanpour, S

2011-06-01

236

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

237

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

Energy Technology Data Exchange (ETDEWEB)

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.)

Tuominen, J.; Lipping, T. (Tampere Univ. of Technology, Pori (Finland))

2011-03-15

238

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.)

2011-01-01

239

Improved remote sensing detection of soil salinity from a semi-arid climate in Northeast Brazil  

Science.gov (United States)

Remote sensing techniques are being increasingly applied to investigate soil characteristics. Here we propose an approach that allows the detection of salt-affected soils in arid and semi-arid environments. We test the procedure in Northeast Brazil through a combination of remote sensing and geochemical ground-based measurements. Spectral indices were used to characterize soil salinization features and patterns. The Linear Spectral Unmixing technique (LSU) is applied in this study to improve the prediction of soil salinity. Eighteen indices were extracted from the MODIS Terra data. A moderate correlation was found between electrical conductivity and the spectral indices. An improvement occurs in most of the correlations after applying the LSU method. To generate a predicted salinity map, a multiple linear regression, based on the best correlated indices is conducted. The standard error of the estimate is about 12.1 ?S cm -1.

Bouaziz, Moncef; Matschullat, Jörg; Gloaguen, Richard

2011-11-01

240

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

CERN Document Server

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...

Babykalpana, Y

2010-01-01

 
 
 
 
241

An initial experimental study-the value of gadolinium-enhanced MRI and delay enhanced MRI in detecting articular cartilage degeneration of the rabbit knee  

International Nuclear Information System (INIS)

Objective: To explore the appearance and value of early and delaye Gadolinium- enhanced MRI in detecting aricular cartilage generation of rabbit knee. Methods: Twenty adult New Zealand rabbits were randomly divided into five groups (A, B, C, D, E). Intra-articular injection of Papain was performed to establish animal models of different stages of cartilage degeneration in the right knees of A, B, C, D groups, and MR scan was conducted 24 hours,one week one month and three months after the last Papain injection. The knees were scanned bilaterally with T1WI and 3D-FS-SPGR in sagittal plane. The signal intensity ratio between articular cartilage and surrounding soft tissue was measured at plain scan and 0, 2, 4 hours after intravenous injection of gadolinium (Gd-DTPA). The articular cartilage was pathologically examined (HE and alcican blue stain). Results: In 3D-FS-SPGR sequence, it showed significant difference in the SIR between processing side of four groups (F=7.961, P1WI sequence in detecting the change of cartilage signal intensity. (2)SIR on early and delayed Gadolinium-enhanced MRI has the ability in evaluating the early stage change of cartilage degeneration. (authors)

2007-12-01

242

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 techniques. Making use of satellite images of 2001, topographic maps and aerial photographs of previous years, were used to determine geomorphological aspects of change detection and geomorphology of the region.

Mustafa Bolca

2005-01-01

243

Detection of rice sheath blight for in-season disease management using multispectral remote sensing  

Science.gov (United States)

Timely diagnosis of crop diseases in fields is critical for precision on-farm disease management. Remote sensing technology can be used as an effective and inexpensive method to identify diseased plants in a field scale. However, due to the diversity of crops and their associated diseases, application of the technology to agriculture is still in research stage, which needs to be elaborately investigated for algorithm development and standard image processing procedures. In this paper, we examined the applicability of broadband high spatial-resolution ADAR (Airborne Data Acquisition and Registration) remote sensing data to detect rice sheath blight and developed an approach to further explore the applicability. Based on the field symptom measurements, a comprehensive field disease index (DI) was constructed to measure infection severity of the disease and to relate to image sampled infections. In addition to direct band digital number (DN) values, band ratio indices and standard difference indices were used to examine possible correlations between field and image data. The results indicated that the broadband remote sensing imagery has the capability to detect the disease. Some image indices such as RI 14, SDI 14 and SDI 24 worked better than others. A correlation coefficient above 0.62 indicated that these indices would be valuable to use for identification of the rice disease. In the validation analysis, we obtained a small root mean square error (RMS = 9.1), confirming the applicability of the developed method. Although the results were encouraging, it was difficult to discriminate healthy plants from light infection ones when DI 35). This phenomenon illustrated that remote sensing images with higher spectral resolution (more bands and narrower bandwidth) were required in order to further examine the capability of separating the light diseased plants from healthy plants.

Qin, Zhihao; Zhang, Minghua

2005-08-01

244

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

Science.gov (United States)

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.

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

2013-10-01

245

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)

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.)

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

246

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.)

2011-09-01

247

Quantitative tissue pH measurement during cerebral ischemia using amine and amide concentration-independent detection (AACID) with MRI.  

Science.gov (United States)

Tissue pH is an indicator of altered cellular metabolism in diseases including stroke and cancer. Ischemic tissue often becomes acidic due to increased anaerobic respiration leading to irreversible cellular damage. Chemical exchange saturation transfer (CEST) effects can be used to generate pH-weighted magnetic resonance imaging (MRI) contrast, which has been used to delineate the ischemic penumbra after ischemic stroke. In the current study, a novel MRI ratiometric technique is presented to measure absolute pH using the ratio of CEST-mediated contrast from amine and amide protons: amine/amide concentration-independent detection (AACID). Effects of CEST were observed at 2.75 parts per million (p.p.m.) for amine protons and at 3.50 p.p.m. for amide protons downfield (i.e., higher frequency) from bulk water. Using numerical simulations and in vitro MRI experiments, we showed that pH measured using AACID was independent of tissue relaxation time constants, macromolecular magnetization transfer effects, protein concentration, and temperature within the physiologic range. After in vivo pH calibration using phosphorus ((31)P) magnetic resonance spectroscopy ((31)P-MRS), local acidosis is detected in mouse brain after focal permanent middle cerebral artery occlusion. In summary, our results suggest that AACID represents a noninvasive method to directly measure the spatial distribution of absolute pH in vivo using CEST MRI. PMID:24496171

McVicar, Nevin; Li, Alex X; Gonçalves, Daniela F; Bellyou, Miranda; Meakin, Susan O; Prado, Marco Am; Bartha, Robert

2014-04-01

248

Using fMRI to Detect Activation of the Cortical and Subcortical Auditory Centers: Development of a Standard Protocol for a Conventional 1.5-T MRI Scanner  

Energy Technology Data Exchange (ETDEWEB)

We wanted to develop a standard protocol for auditory functional magnetic resonance imaging (fMRI) for detecting blood oxygenation level-dependent (BOLD) responses at the cortical and subcortical auditory centers with using a 1.5-T MRI scanner. Fourteen normal volunteers were enrolled in the study. The subjects were stimulated by four repetitions of 32 sec each with broadband white noise and silent period blocks as a run (34 echo planar images [EPIs]). Multiple regression analysis for the individual analysis and one-sample t-tests for the group analysis were applied (FDR, p <0.05). The auditory cortex was activated in most of the volunteers (left 100% and right 92.9% at an uncorrected p value <0.05, and left 92.9% and right 92.9% at an uncorreced p value <0.01). The cochlear nuclei (100%, 85.7%), inferior colliculi (71.4%, 64.3%), medial geniculate bodies (64.3%, 35.7%) and superior olivary complexes (35.7%, 35.7%) showed significant BOLD responses at uncorrected p values of <0.05 and p <0.01, respectively. On the group analysis, the cortical and subcortical auditory centers showed significant BOLD responses (FDR, p <0.05), except for the superior olivary complex. The signal intensity time courses of the auditory centers showed biphasic wave forms. We successfully visualized BOLD responses at the cortical and subcortical auditory centers using appropriate sound stimuli and an image acquisition method with a 1.5-T MRI scanner.

Tae, Woo Suk; Kim, Sam Soo; Lee, Kang Uk; Lee, Seung Hwan; Nam, Eui Cheol [Kangwon National University School of Medicine, Chuncheon (Korea, Republic of); Choi, Hyun Kyung [Kangwon National University Hospital, Chuncheon (Korea, Republic of)

2009-11-15

249

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

Science.gov (United States)

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

Uehara, K; Tai, H

1992-02-20

250

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)

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.)

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

251

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  

International Nuclear Information System (INIS)

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.)

2014-01-01

252

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)

2008-02-01

253

Contextualizing neuro-collaborations: reflections on a transdisciplinary fMRI lie detection experiment.  

Science.gov (United States)

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 research project in functional magnetic resonance imaging (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. PMID:24744713

Littlefield, Melissa M; Fitzgerald, Des; Knudsen, Kasper; Tonks, James; Dietz, Martin J

2014-01-01

254

Tumorsize dependent detection rate of endorectal MRI of prostate cancer-A histopathologic correlation with whole-mount sections in 70 patients with prostate cancer  

International Nuclear Information System (INIS)

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 2 cm 50/56 (89%). False positive eMRI findings were: 2 cm n = 2. Conclusion: T2w eMRI cannot exclude prostate cancer with lesions smaller 10 mm and 0.4 cm3 respectively. The detection rate for lesions more than 20 mm (1.6 cm3) is to be considered as high.

2011-08-01

255

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)

2012-12-01

256

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2005-01-01

257

In vivo detection of free radicals in mouse septic encephalopathy using molecular MRI and immuno-spin trapping.  

Science.gov (United States)

Free radicals are known to play a major role in sepsis. Combined immuno-spin trapping and molecular magnetic resonance imaging (MRI) was used to detect in vivo and in situ levels of free radicals in murine septic encephalopathy after cecal ligation and puncture (CLP). DMPO (5,5-dimethyl pyrroline N-oxide) was injected over 6h after CLP, before administration of an anti-DMPO probe (anti-DMPO antibody bound to albumin-gadolinium-diethylene triamine pentaacetic acid-biotin MRI targeting contrast agent). In vitro assessment of the anti-DMPO probe in oxidatively stressed mouse astrocytes significantly decreased T1 relaxation (p 3-nitrotyrosine (quantitative, p < 0.05 for both), were elevated in septic brains compared to shams. This is the first study that has reported on the detection of in vivo and in situ levels of free radicals in murine septic encephalopathy. PMID:23978375

Towner, Rheal A; Garteiser, Philippe; Bozza, Fernando; Smith, Nataliya; Saunders, Debra; d' Avila, Joana C P; Magno, Flora; Oliveira, Marcus F; Ehrenshaft, Marilyn; Lupu, Florea; Silasi-Mansat, Robert; Ramirez, Dario C; Gomez-Mejiba, Sandra E; Mason, Ronald P; Castro Faria-Neto, Hugo C

2013-12-01

258

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

Energy Technology Data Exchange (ETDEWEB)

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.

Plamen Alexandroz Ivanov

2002-08-27

259

Remote viewing with the artist Ingo Swann: neuropsychological profile, electroencephalographic correlates, magnetic resonance imaging (MRI), and possible mechanisms.  

Science.gov (United States)

In the present study, the artist Ingo Swann, who helped develop the process of remote viewing (awareness of distant objects or places without employing normal senses), was exposed during a single setting of 30 min. to specific patterns of circumcerebral magnetic fields that significantly altered his subjective experiences. Several times during subsequent days, he was asked to sit in a quiet chamber and to sketch and to describe verbally distant stimuli (pictures or places) beyond his normal senses. The proportions of unusual 7-Hz spike and slow wave activity over the occipital lobes per trial were moderately correlated (rho=.50) with the ratings of accuracy between these distal, hidden stimuli and his responses. A neuropsychological assessment and Magnetic Resonance Imaging indicated a different structural and functional organization within the parieto-occipital region of the subject's right hemisphere from organizations typically noted. The results suggest that this type of paranormal phenomenon, often dismissed as methodological artifact or accepted as proofs of spiritual existence, is correlated with neurophysiological processes and physical events. Remote viewing may be enhanced by complex experimentally generated magnetic fields designed to interact with the neuromagnetic "binding factor" of consciousness. PMID:12081299

Persinger, M A; Roll, W G; Tiller, S G; Koren, S A; Cook, C M

2002-06-01

260

Gadolinium-Hematoporphyrin: new potential MRI contrast agent for detection of breast cancer cell line (MCF-7)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Background: Gadolinium-porphyrins have been synthesized and are currently being investigated as magnetic resonance imaging (MRI) contrast agents. This study aimed to synthesize Gd-hematoporphyrin and applicate it for in vitro detection of breast cancer cell line (MCF-7). Methods: The naturally occurring porphyrin (hematoporphyrin) was inserted with gadolinium (III) nitrate hexahydrate to yield Gd-H. T1 relaxation times and signal enhancement of the contrast agents were presented, and the...

Shahbazi Gahrouei, D.; Mb, Tavakoli; Nazari, V.

2005-01-01

 
 
 
 
261

Remote detection of biological particles and chemical plumes using UV fluorescence lidar  

Science.gov (United States)

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.

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

262

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

Science.gov (United States)

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

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

2013-04-01

263

MRI in prostate carcinoma - conventional versus endorectal surface coil MRI  

International Nuclear Information System (INIS)

In a prospective study an attempt was made to determine the value of conventional MRI (354 patients) and MRI using the endorectal surface coil (ESC) (36 patients) in the preoperative staging of prostatic carcinoma. Local preoperative staging with conventional MRI was correct in 83.9% and 88.9% with ESC-MRI. Compared to conventional MRI, ESC-MRI was better in the delineation of the prostatic capsule and early detection of infiltration into the neurovascular bundle. Lymph node staging with MRI showed a sensitivity of 54.4% in detecting pelvic lymph node metastasis. MRI is as limited as CT in assessing pelvic lymph node metastasis. (orig.)

1994-10-01

264

Detection of damaged forest by tomicus piniperda using multiple types of remote sensing data  

Science.gov (United States)

This paper analyzed the damaged forest by tomicus piniperda using multiple types of remote sensing data such as TM, CBERS-1, AVHRR and MODIS data. It selected a typical region including heavy damaged and healthy forest. The region was located by GPS (Global Position System). Then the spectral features of the above remote sensing data (March, 2001) were given. It indicates that the values of healthy forest of TM NIR band (0.76-0.9 ) and SWIR band (1.55-1.75 ) are distinctly greater than those of damaged forest. The values of CBERS-1 NIR bands (0.77-0.89 ), AVHRR bands (0.725-1.0 ) and MODIS bands (0.841-0.876 ) behave in the same pattern with TM. Otherwise, the values of MODIS thermal bands (3.929-3.89 , 10.78-11.28 and 11.77-12.27 ) of damaged forest are distinctly greater than those of healthy forest. The AVHRR thermal bands are not so. Finally, two detection models were put forward according to the spectral changing characteristics. One was named Difference Rate (DR) model with NIR and VIR data, which applied for TM, CBERS-1, AVHRR and MODIS. DR is greater, the forest grow healthily. Basis on the typical sample, the different guidelines distinguished healthy and damaged forests are obtained. The other model was named Disaster Index (DI) model with thermal and NIR data, only suitable for MODIS. The guidelines of healthy and damaged forest are determined too. DI is greater the forest is stricken more badly. In conclusion, it will help monitoring and assessing the vermin occurrence and impact by remote sensing detection model.

Dong, Xieqiong; Feng, Xuezhi; Zhao, Shuhe; Yang, Xiaopeng; Liu, Hongping; Xu, Hong; Ke, Yinghai

2005-01-01

265

MRI, CT, sonography and thallium-technetium subtraction scintigraphy for the detection of parathyroid disease: a four-year experience  

International Nuclear Information System (INIS)

Sonography, subtraction scintigraphy, computed tomography and MRI were compared in 100 patients who had surgery 105 times for hyperparathyroidism (HPT). Surgical and pathological data were available for all operations. A total of 105 MR, 77 CT, 84 sonograms and 70 subtraction scintigrams were performed. The ability of the imaging modalities, individually and in combination, to detect HPT, histology, size, concomitant thyroid disease and location of the diseased glands has been evaluated. For primary HPT, sensitivity ranged from 68% for MRI to 40% for scintigraphy but was much lower for tertiary HPT with all modalities. The ability to identify diseased glands was strongly size dependent for all methods. If patients had had previous neck surgery, the most sensitive methods were MRI and scintigraphy and this also held true for patients with concomitant thyroid disease and ectopically located glands. The findings presented suggest that while sonography may be the only imaging examination warranted in newly diagnosed parathyroid disease, recurrent disease should be examined pre-operatively with MRI and possibly subtraction scintigraphy. (orig.)

1993-01-01

266

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

1989-01-01

267

Beyond blood brain barrier breakdown – in vivo detection of occult neuroinflammatory foci by magnetic nanoparticles in high field MRI  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Gadopentate dimeglumine (Gd-DTPA enhanced magnetic resonance imaging (MRI is widely applied for the visualization of blood brain barrier (BBB breakdown in multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis (EAE. Recently, the potential of magnetic nanoparticles to detect macrophage infiltration by MRI was demonstrated. We here investigated a new class of very small superparamagnetic iron oxide particles (VSOP as novel contrast medium in murine adoptive-transfer EAE. Methods EAE was induced in 17 mice via transfer of proteolipid protein specific T cells. MR images were obtained before and after application of Gd-DTPA and VSOP on a 7 Tesla rodent MR scanner. The enhancement pattern of the two contrast agents was compared, and correlated to histology, including Prussian Blue staining for VSOP detection and immunofluorescent staining against IBA-1 to identify macrophages/microglia. Results Both contrast media depicted BBB breakdown in 42 lesions, although differing in plaques appearances and shapes. Furthermore, 13 lesions could be exclusively visualized by VSOP. In the subsequent histological analysis, VSOP was localized to microglia/macrophages, and also diffusely dispersed within the extracellular matrix. Conclusion VSOP showed a higher sensitivity in detecting BBB alterations compared to Gd-DTPA enhanced MRI, providing complementary information of macrophage/microglia activity in inflammatory plaques that has not been visualized by conventional means.

Schnorr Joerg

2009-08-01

268

Detecting remote evolutionary relationships among proteins by large-scale semantic embedding.  

Science.gov (United States)

Virtually every molecular biologist has searched a protein or DNA sequence database to find sequences that are evolutionarily related to a given query. Pairwise sequence comparison methods--i.e., measures of similarity between query and target sequences--provide the engine for sequence database search and have been the subject of 30 years of computational research. For the difficult problem of detecting remote evolutionary relationships between protein sequences, the most successful pairwise comparison methods involve building local models (e.g., profile hidden Markov models) of protein sequences. However, recent work in massive data domains like web search and natural language processing demonstrate the advantage of exploiting the global structure of the data space. Motivated by this work, we present a large-scale algorithm called ProtEmbed, which learns an embedding of protein sequences into a low-dimensional "semantic space." Evolutionarily related proteins are embedded in close proximity, and additional pieces of evidence, such as 3D structural similarity or class labels, can be incorporated into the learning process. We find that ProtEmbed achieves superior accuracy to widely used pairwise sequence methods like PSI-BLAST and HHSearch for remote homology detection; it also outperforms our previous RankProp algorithm, which incorporates global structure in the form of a protein similarity network. Finally, the ProtEmbed embedding space can be visualized, both at the global level and local to a given query, yielding intuition about the structure of protein sequence space. PMID:21298082

Melvin, Iain; Weston, Jason; Noble, William Stafford; Leslie, Christina

2011-01-01

269

Cloud Detection Method Based on Feature Extraction in Remote Sensing Images  

Science.gov (United States)

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.

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

2013-05-01

270

The contribution of remote sensing data for the detection of natural selection signatures in North American Grey Wolves  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The current thesis constitutes an interdisciplinary approach of detecting a selection pressure driven by the environment examining the contribution of Remote Sensing and Spatial Analysis in the field of Landscape Genetics. Even though several studies have been attempting to link genetic and environmental information so as to discover the genes that are being shaped by natural selection because of various interacted environmental factors, aspiring remote sensing derived parameters may have not...

Samoili, Sofia

2010-01-01

271

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

2001-01-01

272

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

273

Noninvasive detection of neural progenitor cells in living brains by MRI  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The presence of pericytes in brain regions undergoing repair is evident of the recruitment of bone marrow-derived multipotent regenerative cells to the neurovascular unit during angiogenesis. At present, post mortem sampling is the only way to identify them. Therefore, such cell typing is inadequate for preserving neural progenitor cells for any meaningful stem cell therapy. We aimed to target cerebral pericytes in vivo using dual gene transcript-targeted MRI (GT-tMRI) in male C57black6 mice ...

Liu, Christina H.; Ren, Jia Q.; You, Zerong; Yang, Jinsheng; Liu, Charng-ming; Uppal, Ritika; Liu, Philip K.

2012-01-01

274

Detection of an occult transclival cerebrospinal fluid fistula by CT and MRI  

International Nuclear Information System (INIS)

We describe an unusual occult transclival cerebrospinal fluid (CSF) fistula to the sphenoid sinus demonstrated by MRI. CT was performed because of a posterior cerebral infarct caused by cardiac arrhythmia. Axial sections showed fluid in the sphenoid sinus. High-resolution scans revealed a bony defect 3 mm in diameter of the posterior wall of the sphenoid sinus, and MRI showed a transclival CSF fistula. This occult lesion was confirmed by surgery and duraplasty was successfully performed via an endonasal approach. (orig.)

1998-12-01

275

An Entropy Based Method for Activation Detection of functional MRI Data Using Independent Component Analysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Independent Component Analysis (ICA) can be used to decompose functional Magnetic Resonance Imaging (fMRI) data into a set of statistically independent images which are likely to be the sources of fMRI data. After applying ICA, a set of independent components are produced, and then, a “meaningful” subset from these components must be identified, because a large majority of components are non interesting. So, interpreting the components is an important and also difficult task. In this pape...

2010-01-01

276

Liver tumor laser ablation - increase in the subacute ablation lesion volume detected with post procedural MRI  

International Nuclear Information System (INIS)

Background: The use of image-guided thermoablative methods in liver tumor treatment has expanded rapidly due to encouraging results and advanced imaging. However, little is known about the treatment-induced tissue response and effects on imaging findings during the subacute post procedural period. Purpose: To study the development of subacute ablation zone volume with magnetic resonance imaging (MRI) after laser-mediated liver tumor thermal therapy. Material and Methods: In all, 16 laser ablations were performed on 16 liver tumors resulting in 16 ablation zones in 11 consecutive patients. A low-field 0.23 T C-arm MRI scanner was used for imaging and procedural guidance. Repeated dynamic contrast-enhanced T1, contrast-enhanced T1 FSE, and T2 FSE studies of liver were performed at 0 and 72 h after the procedure. Ablation zone volumes were registered from the acquired image data. Results: MRI scans showed a significant increase of ablation volume in all imaging sequences obtained at 72 h after the initial therapy. Conclusion: After laser ablation, there is a progressive perfusion decrease in the ablation site leading to an increase in the ablation volume. Post procedural baseline MRI at 72 h from the treatment provides more precise information about the ablation result than can be obtained with immediate post procedural MRI . Keywords: MRI guidance, laser, ablation, contrast, time course

2010-06-01

277

Liver tumor laser ablation - increase in the subacute ablation lesion volume detected with post procedural MRI  

Energy Technology Data Exchange (ETDEWEB)

Background: The use of image-guided thermoablative methods in liver tumor treatment has expanded rapidly due to encouraging results and advanced imaging. However, little is known about the treatment-induced tissue response and effects on imaging findings during the subacute post procedural period. Purpose: To study the development of subacute ablation zone volume with magnetic resonance imaging (MRI) after laser-mediated liver tumor thermal therapy. Material and Methods: In all, 16 laser ablations were performed on 16 liver tumors resulting in 16 ablation zones in 11 consecutive patients. A low-field 0.23 T C-arm MRI scanner was used for imaging and procedural guidance. Repeated dynamic contrast-enhanced T1, contrast-enhanced T1 FSE, and T2 FSE studies of liver were performed at 0 and 72 h after the procedure. Ablation zone volumes were registered from the acquired image data. Results: MRI scans showed a significant increase of ablation volume in all imaging sequences obtained at 72 h after the initial therapy. Conclusion: After laser ablation, there is a progressive perfusion decrease in the ablation site leading to an increase in the ablation volume. Post procedural baseline MRI at 72 h from the treatment provides more precise information about the ablation result than can be obtained with immediate post procedural MRI . Keywords: MRI guidance, laser, ablation, contrast, time course

Blanco Sequeiros, Roberto; Kariniemi, Juho; Ojala, Risto; Haapea, Marianne; Blanco Sequeiros, Andreas; Tervonen, Osmo (Dept. of Radiology, Oulu Univ. Hospital, Oulu (Finland)), e-mail: roberto.blanco@oulu.fi; Chengli Li (Shangdong Provincial Medical Imaging Research Inst., Jinan (China))

2010-06-15

278

Detection of infarct lesions from brain MRI images using inconsistency between voxel intensity and spatial location. A 3D automatic approach.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract—Detection of infarct lesions using traditional segmentation methods is always problematic due to intensity similarity between lesions and normal tissues, so that multi-spectral magnetic resonance imaging (MRI) modalities were often employed for this purpose. However, the high costs of MRI scan and the severity of patient conditions restrict the collection of multiple images. Therefore, in this paper, a new 3D automatic lesion detection approach was proposed, which required only ...

Shen, S.; Szameitat, A.; Sterr, A.

2008-01-01

279

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

Energy Technology Data Exchange (ETDEWEB)

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 eingeschra

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

2002-05-01

280

Does low-field dedicated extremity MRI (E-MRI) reliably detect RA bone erosions? A comparison of two different E-MRI units and conventional radiography with high resolution CT  

DEFF Research Database (Denmark)

OBJECTIVES: To compare the ability of 2 different E-MRI units and conventional radiography (CR) to identify bone erosions in rheumatoid arthritis (RA) metacarpophalangeal (MCP) and wrist joints, with computed tomography (CT) as standard reference method. METHODS: 20 RA patients and 5 controls underwent, within 2 weeks, CR, CT and two E-MRI (Esaote Biomedica; Artoscan and MagneVu; MV1000) examination of one hand. In all modalities each bone of wrist and (MCP) joints was blindedly evaluated for erosions. Furthermore, MagneVu images were assessed for the proportion of each bone being visualized. 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 Artoscan for detecting erosions was higher than of 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 visualization of 1.5 cm of the ventral-dorsal diameter of the bone. In the wrist 31.6% of bones were visualized entirely and 37.9% of bones were 67-99% visualized. In MCP joints, 84.2% of bones were visualized entirely and 15.8% of bones were 67-99% visualized. CONCLUSION: With CT as reference method for detecting erosions in RA hands, Artoscan showed higher sensitivity than MagneVu and CR. All imaging modalities revealed high specificities. The better performance of Artoscan should be considered when selecting imaging method in RA.

Duer, Anne; Ejbjerg, Bo

2008-01-01

 
 
 
 
281

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)

2004-05-01

282

Detection of hepatocellular carcinoma by Gd-EOB-DTPA-enhanced liver MRI: Comparison with triple phase 64 detector row helical CT  

Energy Technology Data Exchange (ETDEWEB)

Purpose: To compare the diagnostic performance of Gd-EOB-DTPA-enhanced MRI with that of triple phase 64-MDCT in the detection of hepatocellular carcinoma (HCC). Patients and methods: Thirty-four patients with 52 surgically proven lesions underwent Gd-EOB-DTPA-enhanced MRI and triple phase 64-MDCT. Two observers independently evaluated MR and CT imaging on a lesion-by-lesion basis. Sensitivity, positive and negative predictive values and reproducibility were evaluated. The diagnostic accuracy of each modality was assessed with alternative-free response receiver operating characteristic (ROC) analysis. Results: Both observers showed higher sensitivity in detecting lesions with MRI compared to CT, however, only the difference between the two imaging techniques for observer 2 was significant (P = 0.034). For lesions 1 cm or smaller, MRI and CT showed equal sensitivity (both 62.5%) with one observer, and MRI proved superior to CT with the other observer (MRI 75% vs. CT 56.3%), but the latter difference was not significant (P = 0.083). The difference in positive and negative predictive value between the two imaging techniques for each observer was not significant (P > 0.05). The areas under the ROC curve for each observer were 0.843 and 0.861 for MRI vs. 0.800 and 0.833 for CT and the differences were not significant. Reproducibility was higher using MRI for both observers, but the result was not significant (MRI 32/33 vs. CT 29/33, P = 0.083). Conclusion: Gd-EOB-DTPA-enhanced MRI tended to show higher diagnostic accuracy, sensitivity and reproducibility compared to triple phase 64-MDCT in the detection of hepatocellular carcinoma, however statistical significance was not achieved.

Akai, Hiroyuki, E-mail: hakai-tky@umin.ac.jp [Department of Radiology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655 (Japan); Kiryu, Shigeru [Department of Radiology, Institute of Medical Science, University of Tokyo, 74-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639 (Japan); Matsuda, Izuru; Satou, Jirou; Takao, Hidemasa; Tajima, Taku [Department of Radiology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655 (Japan); Watanabe, Yasushi [Department of Radiological Technology, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655 (Japan); Imamura, Hiroshi [Department of Hepatobiliary-Pancreatic Surgery, Juntendo University School of Medicine, 3-1-3 Hongo, Bunkyo-ku, Tokyo 113-8431 (Japan); Kokudo, Norihiro [Hepato-Biliary-Pancreatic Surgery Division, Department of Surgery, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655 (Japan); Akahane, Masaaki; Ohtomo, Kuni [Department of Radiology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655 (Japan)

2011-11-15

283

Remote detection of artificially triggered avalanches below a fixed avalanche control installation  

Science.gov (United States)

Avalanche control by explosives is widely used as a temporary preventive measure to reduce avalanche hazard. The goal is to artificially trigger smaller less destructive avalanches, by detonating charges either above or on the snow surface. Hand charges are most often used, whereby the explosives are deployed by manually hand tossing or lowering onto the snow slope. Given the inherent dangers and limitations of this type of avalanche control, fixed avalanche control installations are increasingly used. These consist of strategically placed remote controlled installations that generate an explosion above the snow pack in an avalanche starting zone. While fixed installations can be used at any time and minimize the risk to avalanche control personnel, visual confirmation is still required to verify if an avalanche released. In order to remotely detect artificially triggered avalanches, we therefore developed a low-cost seismic monitoring system. We deployed the monitoring system in a ski area above the town of Davos , in the eastern Swiss Alps, below a Gazex installation, a remote controlled installation that generates an air blast by detonating a fuel-air explosive above the snow pack. The monitoring system consists of three vertical component geophones inserted in the ground at approximately 14, 27 and 46 meters from the Gazex installation. Our results show that, despite the relatively low precision of the monitoring equipment, both the detonation and the resulting avalanches can clearly be identified in the seismic data. Specifically, detonations are characterized by short, high amplitude broadband signals, while avalanches generate much longer, low frequency signals. Furthermore, information on the size of the artificially triggered avalanches is also obtained as it directly relates to the duration of the generated seismic signal. The overall goal is to assess the effectiveness of the fixed avalanche control installation with regards to yield (i.e. number of avalanches triggered per explosion) and avalanche size.

van Herwijnen, Alec; Simioni, Stephan; Schweizer, Juerg

2014-05-01

284

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

1998-01-01

285

Remote infrasound monitoring of Mount Etna: Observed and predicted network detection capability  

Science.gov (United States)

Volcanic eruptions are unique and valuable calibrating sources of infrasonic waves worldwide detected by the International Monitoring System (IMS) of the Comprehensive nuclear Test Ban Treaty Organization (CTBTO) and other experimental stations. Building a comprehensive database of volcanic signals is likely to help the scientific community to better characterize eruptive sequences and may help to prevent eruption disasters while on a longer term mitigate the impact of ash clouds on aviation. In this study, we assess the detection capability of the existing infrasound network to remotely detect the eruptive activity of Mount Etna with a high level of confidence, and predict the performance of the future ARISE infrastructure network (Atmospheric dynamics InfraStructure in Europe). This well-instrumented volcano offers a unique opportunity to validate attenuation models using multiyear near-and-far field recordings. The seasonal trend in the number of detections of Etna at the IS48 IMS station (Tunisia) is correlated to fine temporal fluctuations of the stratospheric waveguide structure. The modeling results are consistent with the observed detection capability of the existing network. In summer, during the downwind season, a minimum detectable amplitude of ~10 Pa at a reference distance of 1 km from the source is predicted. In winter, when upwind propagation occurs, detection thresholds increase up to ~100 Pa. When adding four experimental arrays to the existing IMS network, thresholds decrease down to ~20 Pa in winter. The simulation results provide here a realistic description of long-range infrasound propagation and allow predicting fine temporal fluctuations in the European infrasound network performance with potential application for civil aviation safety.

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

2013-04-01

286

Change detection based on the high-resolution remote sensing images  

Science.gov (United States)

With the development of remote sensing technology, satellites can collect high spatial resolution images such as SPOT-5 and Quickbird. The SPOT-5 satellite simultaneously collects 5-m panchromatic and 10-m multispectral images, after interpolated in ground station 2.5-m panchromatic image can be provided (5 metres ground resolution in panchromatic mode and 2.5 metres in supermode). The Quick bird satellite simultaneously collects 0.61-m panchromatic and 2.44-m multispectral images. With Images Merged of 2.5-m panchromatic and 10-m multispectral images of SPOT-5, the approximate resolution images as Quick bird multispectral images were acquired. These images acquired with different satellites can be used to detect the change of urban. In this paper, the images of Wuhan University in China acquired with SPOT-5 and Quick bird are used to detect the change of trees in different season. The result shows it is possible to detect the change of trees and some factors that affect the change detection are listed.

Zhou, Junqi; Sun, Jiabing; Zhang, Hong

2005-11-01

287

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

1996-08-01

288

Diffusion fMRI detects white-matter dysfunction in mice with acute optic neuritis.  

Science.gov (United States)

Optic neuritis is a frequent and early symptom of multiple sclerosis (MS). Conventional magnetic resonance (MR) techniques provide means to assess multiple MS-related pathologies, including axonal injury, demyelination, and inflammation. A method to directly and non-invasively probe white-matter function could further elucidate the interplay of underlying pathologies and functional impairments. Previously, we demonstrated a significant 27% activation-associated decrease in the apparent diffusion coefficient of water perpendicular to the axonal fibers (ADC?) in normal C57BL/6 mouse optic nerve with visual stimulation using diffusion fMRI. Here we apply this approach to explore the relationship between visual acuity, optic nerve pathology, and diffusion fMRI in the experimental autoimmune encephalomyelitis (EAE) mouse model of optic neuritis. Visual stimulation produced a significant 25% (vs. baseline) ADC? decrease in sham EAE optic nerves, while only a 7% (vs. baseline) ADC? decrease was seen in EAE mice with acute optic neuritis. The reduced activation-associated ADC? response correlated with post-MRI immunohistochemistry determined pathologies (including inflammation, demyelination, and axonal injury). The negative correlation between activation-associated ADC? response and visual acuity was also found when pooling EAE-affected and sham groups under our experimental criteria. Results suggest that reduction in diffusion fMRI directly reflects impaired axonal-activation in EAE mice with optic neuritis. Diffusion fMRI holds promise for directly gauging in vivo white-matter dysfunction or therapeutic responses in MS patients. PMID:24632420

Lin, Tsen-Hsuan; Spees, William M; Chiang, Chia-Wen; Trinkaus, Kathryn; Cross, Anne H; Song, Sheng-Kwei

2014-07-01

289

A combined remote Raman and fluorescence spectrometer system for detecting inorganic and biological materials  

Science.gov (United States)

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 CaCO3 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 µs, 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.

Sharma, Shiv K.; Misra, Anupam K.; Lucey, Paul G.

2006-12-01

290

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.)

2009-03-01

291

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  

Energy Technology Data Exchange (ETDEWEB)

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 T{sub 2}-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.)

Bondt, R.B.J. de; Bakers, F.; Hofman, P.A.M. [Maastricht University Medical Center, Department of Radiology, Maastricht (Netherlands); Nelemans, P.J. [Maastricht University Medical Center, Department of Epidemiology, Maastricht (Netherlands); Casselman, J.W. [AZ St. Jan Hospital, Department of Radiology, Bruges (Belgium); Peutz-Kootstra, C. [Maastricht University Medical Center, Department of Pathology, Maastricht (Netherlands); Kremer, B. [Maastricht University Medical Center, Department of Otolaryngology/ Head and Neck Surgery, Maastricht (Netherlands); Beets-Tan, R.G.H. [Academic Hospital Maastricht, Department of Radiology, Maastricht (Netherlands)

2009-03-15

292

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.

2009-07-01

293

Nuclear magnetic resonance method and apparatus for remote detection and volumetric measurement of petroleum reserves  

Energy Technology Data Exchange (ETDEWEB)

A new and practical method is provided for the remote detection and direct volumetric measurement of petroleum reservoirs. The nucleons chemically bound in water and oil present in a formation are preferentially aligned in the earth's magnetic field, causing natural nuclear paramagnetism within the formation. This paramagnetism causes a slight alteration in the strength of the earth's magnetic field in the vicinity of a borehole adjacent to the formation. Repeated application of an ac magnetic field at the Larmor frequency of the nucleons present yields an amplitude modulation of the earth's magnetic field. The magnitude of such modulation yields the total number of nucleons present and the phase contains information used to provide information regardless of oil and water present in the formation. The invention also provides an apparatus for carrying out the above method. 6 figs.

Vail, W.B.

1987-02-10

294

Detection of an occult transclival cerebrospinal fluid fistula by CT and MRI  

Energy Technology Data Exchange (ETDEWEB)

We describe an unusual occult transclival cerebrospinal fluid (CSF) fistula to the sphenoid sinus demonstrated by MRI. CT was performed because of a posterior cerebral infarct caused by cardiac arrhythmia. Axial sections showed fluid in the sphenoid sinus. High-resolution scans revealed a bony defect 3 mm in diameter of the posterior wall of the sphenoid sinus, and MRI showed a transclival CSF fistula. This occult lesion was confirmed by surgery and duraplasty was successfully performed via an endonasal approach. (orig.) With 3 figs., 19 refs.

Schick, B.; Brors, D.; Draf, W. [Department of Ear, Nose and Throat Diseases, Head, Neck and Facial Plastic Surgery, Marburg Univ. (Germany); Goedecke, A. [Department of Radiology, Academic Teaching Hospital, Fulda (Germany); Prescher, A. [Department of Anatomy and Embryology, University Medical School, RWTH, Aachen (Germany)

1998-12-01

295

Early detection by MRI and conservative therapy of lumbar spondylolysis in the growing period  

Energy Technology Data Exchange (ETDEWEB)

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)

Yoshida, Tohru; Namba, Hiromichi; Kasai, Tsutomu; Ohta, Susumu [Yoshida Orthopaedic Hospital, Toyota, Aichi (Japan)

1996-07-01

296

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

Science.gov (United States)

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.

Hatsukade, Yoshimi; Tsunaki, Shingo; Yamamoto, Masaaki; Abe, Takayuki; Hatta, Junichi; Tanaka, Saburo

2013-11-01

297

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)

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.

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

298

Additional diffusion-weighted imaging in the detection of new, very small hepatocellular carcinoma lesions after interventional therapy compared with conventional 3 T MRI alone  

International Nuclear Information System (INIS)

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/mm2. 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.

2012-07-01

299

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

Directory of Open Access Journals (Sweden)

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.

V.PADMAJA, KAVITHA MAMINDLA

2013-11-01

300

AIRBORNE, OPTICAL REMOTE SENSING OF METHANE AND ETHANE FOR NATURAL GAS PIPELINE LEAK DETECTION  

Energy Technology Data Exchange (ETDEWEB)

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.

Jerry Myers

2003-05-13

 
 
 
 
301

Evolution of Coral Rubble Deposits on a Reef Platform as Detected by Remote Sensing  

Directory of Open Access Journals (Sweden)

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.

Ana Vila-Concejo

2012-12-01

302

Remote Sensing of Strombolian Activity: Frequency-Based Detection and Monitoring Techniques  

Science.gov (United States)

Strombolian activity is one of the most common types of volcanic activity. When this activity occurs at remote volcanoes it often goes undetected and cannot be monitored easily or safely by direct methods. Satellite remote sensing can be useful in the routine monitoring of this activity. Numerous remote volcanoes in the Aleutian Islands and Kamchatka Peninsula exhibit Strombolian explosive activity. Often this type of activity is a precursor to more vigorous activity, including lava flows and ash producing explosions, which can affect communities and transportation. Time-dependent thermal signals were modeled in the lab using honey as a lava analog in scaled explosions. The thermal signals from the spatter fields were recorded with a FLIR thermal camera and were seen to last tens of seconds. Explosions at Stromboli volcano in Italy were recorded using the same thermal camera. These spatter fields, the likely source of thermal signals, were seen to last tens of seconds to minutes. The transient nature of these thermal features, both scaled and actual, indicates that the probability of capturing strombolian style explosions in a satellite overpass is statistically unlikely. However, these thermal signals are seen in imagery and the number of explosions recorded can be used, along with number of passes per day, viewing geometry, and other constraints, to determine a relative frequency of explosive activity. Factors affecting the visibility of thermal anomalies resulting from small explosions include satellite geometry, crater geometry, weather, and time of image capture. Geometric and timing factors eliminate a significant number of satellite passes; only 10-15% of original passes are useable after considering these issues. The remaining passes are analyzed for weather conditions, which in the N. Pacific is a very limiting factor. Weather is determined from cloud cover in a 40x40 km region around the volcano based on a grading system with five categorizations from clear to cloudy. This is used to calculate a probability of a clear view at the volcano and the likelihood of detecting an explosion. This statistic is used to detect changes in relative frequency of explosive activity and possible periods of heightened activity, leading to heightened awareness of possible hazards. Satellite imagery spanning 2005-2010 from Mt. Chuginadak and Shishaldin in Alaska, and Karymsky on the Kamchatkan Peninsula have been analyzed as well as observatory releases and color code assignments to determine base-line activity at those volcanoes.

Worden, A. K.; Dehn, J.

2011-12-01

303

Distributed processing of large remote sensing images using MapReduce - A case of Edge Detection  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Advances in sensor technology and their ever increasing repositories of the collected data are revolutionizing the mechanisms remotely sensed data are collected, stored and processed. This exponential growth of data archives and the increasing user’s demand for real-and near-real time remote sensing data products has pressurized remote sensing service providers to deliver the required services. The remote sensing community has recognized the challenge in processing large and complex satelli...

Tesfamariam, Ermias Beyene

2011-01-01

304

High Energy Protons for Remote Standoff Detection of Special Nuclear Materials  

Science.gov (United States)

High energy protons can be a powerful probe for standoff detection of Special Nuclear Materials (SNM). In particular, the use of protons of 500 MeV and up with modest beam currents, 10 to 100 ?A, can be far more efficient in the production of fission neutrons than conventional bremsstrahlung based electron linacs. Such beams can provide both the range and, more importantly, the sensitivity to fissile materials required for remote detection at distances of hundreds of meters or more. The practical application of this technique has been limited by the requirements of producing such high energy protons using conventional proton accelerators--typically very large, fixed installations. The on-going development at MIT of a new generation of very compact superconducting cyclotrons makes a compelling case for examining this approach for a practical standoff detection system where large numbers of neutrons can be produced using an accelerator with ~1 GeV energy and modest beam currents in the 1 to 100 ?A range. We will describe current work in the design of a 250 MeV, 1 mA superconducting accelerator and its extension to higher energies, and make estimates of sensitivity to reasonable amounts of shielded fissile material.

Lanza, Richard C.; Antaya, Timothy

2011-12-01

305

T2-weighted MRI detects presymptomatic pathology in the SOD1 mouse model of ALS  

Science.gov (United States)

Neuroinflammation has been identified as a potential therapeutic target in amyotrophic lateral sclerosis (ALS), but relevant biomarkers are needed. The superoxide dismutase (SOD1)G93A transgenic mouse model of ALS offers a unique opportunity to study and potentially manipulate presymptomatic pathology. While T2-weighted magnetic resonance imaging (MRI) has been shown to be sensitive to pathologic changes at symptom onset, no earlier biomarkers were previously identified and the underlying histopathologic correlates remain uncertain. To address these issues, we used a multimodal MRI approach targeting structural (T2, T1, apparent diffusion coefficient (ADC), magnetization transfer ratio (MTR)), vascular (gadolinium diethylene triamine pentaacetic acid), and endothelial (vascular cell adhesion molecule–microparticles of iron oxide) changes, together with histopathologic analysis from presymptomatic to symptomatic stages of disease. Presymptomatic changes in brainstem nuclei were evident on T2-weighted images from as early as 60 days (Pastro- and microglial activation all correlated with T2-weighted changes. Significant reductions in ADC (P<0.01) and MTR (P<0.05) were found at 120 days in the same brainstem nuclei. No changes in T1 relaxation, vascular permeability, or endothelial activation were found at any stage of disease. These findings suggest that T2-weighted MRI offers the strongest biomarker potential in this model, and that MRI has unique potential for noninvasive and longitudinal assessment of presymptomatically applied therapeutic and neuroprotective agents.

Evans, Matthew C; Serres, Sebastien; Khrapitchev, Alexandre A; Stolp, Helen B; Anthony, Daniel C; Talbot, Kevin; Turner, Martin R; Sibson, Nicola R

2014-01-01

306

Clustering of Dependent Components: A New Paradigm for fMRI Signal Detection  

Directory of Open Access Journals (Sweden)

Full Text Available Exploratory data-driven methods such as unsupervised clustering and independent component analysis (ICA are considered to be hypothesis-generating procedures and are complementary to the hypothesis-led statistical inferential methods in functional magnetic resonance imaging (fMRI. Recently, a new paradigm in ICA emerged, that of finding "clusters" of dependent components. This intriguing idea found its implementation into two new ICA algorithms: tree-dependent and topographic ICA. For fMRI, this represents the unifying paradigm of combining two powerful exploratory data analysis methods, ICA and unsupervised clustering techniques. For the fMRI data, a comparative quantitative evaluation between the two methods, tree-dependent and topographic ICA, was performed. The comparative results were evaluated by (1 task-related activation maps, (2 associated time courses, and (3 ROC study. The most important findings in this paper are that (1 both tree-dependent and topographic ICA are able to identify signal components with high correlation to the fMRI stimulus, and that (2 topographic ICA outperforms all other ICA methods including tree-dependent ICA for 8 and 9 ICs. However for 16 ICs, topographic ICA is outperformed by tree-dependent ICA (KGV using as an approximation of the mutual information the kernel generalized variance. The applicability of the new algorithm is demonstrated on experimental data.

Hurdal Monica K

2005-01-01

307

T?-weighted MRI detects presymptomatic pathology in the SOD1 mouse model of ALS.  

Science.gov (United States)

Neuroinflammation has been identified as a potential therapeutic target in amyotrophic lateral sclerosis (ALS), but relevant biomarkers are needed. The superoxide dismutase (SOD1)(G93A) transgenic mouse model of ALS offers a unique opportunity to study and potentially manipulate presymptomatic pathology. While T?-weighted magnetic resonance imaging (MRI) has been shown to be sensitive to pathologic changes at symptom onset, no earlier biomarkers were previously identified and the underlying histopathologic correlates remain uncertain. To address these issues, we used a multimodal MRI approach targeting structural (T?, T?, apparent diffusion coefficient (ADC), magnetization transfer ratio (MTR)), vascular (gadolinium diethylene triamine pentaacetic acid), and endothelial (vascular cell adhesion molecule-microparticles of iron oxide) changes, together with histopathologic analysis from presymptomatic to symptomatic stages of disease. Presymptomatic changes in brainstem nuclei were evident on T?-weighted images from as early as 60 days (P<0.05). Histologic indices of vacuolation, astro- and microglial activation all correlated with T?-weighted changes. Significant reductions in ADC (P<0.01) and MTR (P<0.05) were found at 120 days in the same brainstem nuclei. No changes in T? relaxation, vascular permeability, or endothelial activation were found at any stage of disease. These findings suggest that T?-weighted MRI offers the strongest biomarker potential in this model, and that MRI has unique potential for noninvasive and longitudinal assessment of presymptomatically applied therapeutic and neuroprotective agents. PMID:24496176

Evans, Matthew C; Serres, Sébastien; Khrapitchev, Alexandre A; Stolp, Helen B; Anthony, Daniel C; Talbot, Kevin; Turner, Martin R; Sibson, Nicola R

2014-05-01

308

Magnetic mitoxantrone nanoparticle detection by histology, X-ray and MRI after magnetic tumor targeting  

International Nuclear Information System (INIS)

Ferrofluids coated with starch polymers can be used as biocompatible carriers. Bound to medical drugs, such magnetic particles can be enriched in a desired body compartment using an external magnetic field. In the present study, we confirm the enrichment of ferrofluids in tumor tissue using histological investigations and conventional imaging techniques, i.e. X-ray and MRI

2001-01-01

309

Magnetic mitoxantrone nanoparticle detection by histology, X-ray and MRI after magnetic tumor targeting  

Science.gov (United States)

Ferrofluids coated with starch polymers can be used as biocompatible carriers. Bound to medical drugs, such magnetic particles can be enriched in a desired body compartment using an external magnetic field. In the present study, we confirm the enrichment of ferrofluids in tumor tissue using histological investigations and conventional imaging techniques, i.e. X-ray and MRI.

Alexiou, Christoph; Arnold, Wolfgang; Hulin, Peter; Klein, Roswitha Judith; Renz, Helmut; Parak, Fritz Günther; Bergemann, Christian; Lübbe, Andreas Stephan

2001-01-01

310

The Value of Non-EPI Diffusion-Weighted (DW) MRI versus EPI and Conventional MR Sequences in the Detection of Middle Ear Cholesteatoma  

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Background/Objective: The non-echo planar imaging diffusion-weighted (non-EPI DW) MRI sequence has recently emerged as a new imaging technique in detecting cholesteatoma. We have compared the diagnostic efficacy of conventional MRI with this new sequence. "nPatients and Methods: A group of 23 patients (also including second look patients) (16 male, seven female; mean age:34±17.5[9-76] years) were evaluated with MRI, consisting delayed post-contrast, EPI and non-EPI DW sequences, p...

Kavous Firouznia; Hashem Sharifian; Elham Taheri; Amir Reza Azizian; Madjid Shakiba; Pedram Borghei; Reza Farjad; Roshanfekr, M.; Naghdi, N.

2010-01-01

311

Diagnostic value of MRI for detection and differential diagnostic evaluation of focal liver lesions. Wertigkeit der Magnetresonanztomographie in der Detektion und Differentialdiagnose fokaler Leberlaesionen  

Energy Technology Data Exchange (ETDEWEB)

Magnetic resonance imaging (MRI) of the liver has made considerable progress due to improvements in the examination technique. Sensitivity for the detection of focal liver lesions is higher for MRI than for CT. In the differential diagnosis of liver tumors MRI is remarkably accurate. This is particularly true for hemangiomas, liver cell carcinomas and focal nodular hyperplasias. From a clinical view point differentiation between hemangiomas and metastases is of utmost importance. Future improvements in MR diagnosis of liver diseases are expected due to fast imaging techniques and liver-specific contrast agents. (orig.).

Hamm, B. (Klinikum Steglitz, Berlin (Germany). Radiologische Klinik)

1992-05-01

312

Differential diagnosis of MRI detected intra cranial space occupying lesions (ICSOLS)-role of 99MTC tetrofosmin cerebral spect  

International Nuclear Information System (INIS)

Discriminating the correct etiology of Intra Cranial Space Occupying Lesions (ICSOLs) detected by MRI is of paramount importance in deciding the right therapeutic approach. Functional imaging like 99m Tc Tetrofosmin cerebral SPECT (C SPECT) can be used to differentiate malignant from other benign cerebral pathologies. Objective: Our aim was to assess the efficacy of C SPECT in differentiating various etiologies (i.e. Infective / Inflammatory, Neoplastic and Post Radiotherapy changes) of MRI detected ICSOLs. We also aimed to assess the incremental value of quantitative uptake ratios in identifying the exact nature of ICSOLs. Method: 26 Patients (M:F=20:6), age range 28-76 yrs, mean 42±7 yrs were evaluated by 99mTc Tetrofosmin cerebral SPECT. 14/26 patients were HIV positive cases while remaining 12 were treated patients of intracerebral malignancies. All these patients had one or more discrete MRI detected ICSOLs. 6/4 patients with HIV and 4/12 patients in the non HIV group showed more than 1 discrete ICSOLs. 20 mci of 99mTc Tetrofosmin was injected IV .15 min (early) and 2 hrs (delayed) post injection C SPECT images were acquired on a dual head variable angle Gamma camera. After reconstruction, transverse, coronal and sagittal images were co- registered with DICOM online available MRI images using aco- registration software. Focal Tetrofosmin uptake in MRI detected ICSOL was interpreted as abnormal. Tetrofosmin uptake index (Ix) was calculated in early and delayed images as ratio of counts in lesion to that of contra lateral region. A value of more than 1.3 was considered to be abnormal. Persistent Ix of more than 1.3 in initial and delayed images were considered to be malignant while Ix of more or less than 1.3 in initial but less than 1.3 in delayed images was considered to be benign in both groups. Results: In HIV group (14 pts), 4 patients showed an Ix of less than 1.3 in both early and delayed images and 7 patients showed an Ix of more than 1.3 in early but significant washout of Tetrofosmin in delayed images (Ix 1.3). So this 11/14 patients were diagnosed to have an infective / inflammatory SOL (etiology: TB / toxoplasmosis) and were followed up at least for 5 months.10/11 patients improved / did not show any deterioration while 1 patient deteriorated (93% specificity). Remaining 3 patients who showed significant tracer uptake in both images (more than 1.3 Ix) were diagnosed to have cerebral malignancy and underwent stereo tactic biopsy. All were proved to be positive for lymphoma (100 % sensitivity, specificity). In non HIV group (12pts), (i.e.tumour recurrence Vs Post Radiotherapy edema) 5/12 patients showed features of recurrence with a persistent Ix of more than 2.0. and 7/12 patients showed an Ix of more than 1.3 in early but significant washout of Tetrofosmin in delayed images (Ix less than 1.3) prompting a diagnosis of post radiotherapy edema. While benign etiology patients were followed up with conservative measures recurrent malignancy patients were subsequently taken up for radiotherapy. 1 patient in benign group deteriorated and was diagnosed to have a recurrence. (Specificity 85.7%) Conclusion: C SPECT is a very useful tool in further evaluating MRI detected ICSOLs both in HIV positive patients and in follow up patients of treated intra cranial malignancies. An uptake index of 1.3 seems to be a good cut off value while performing C SPECT. (authors)

2004-10-09

313

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 res...

Rischke Hans Christian; Schäfer Arnd O; Nestle Ursula; Volegova-Neher Natalja; Henne Karl; Benz Matthias R; Schultze-Seemann Wolfgang; Langer Mathias; Grosu Anca L

2012-01-01

314

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)

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.)

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

315

Application of nonnegative matrix factorization to improve profile-profile alignment features for fold recognition and remote homolog detection  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Nonnegative matrix factorization (NMF is a feature extraction method that has the property of intuitive part-based representation of the original features. This unique ability makes NMF a potentially promising method for biological sequence analysis. Here, we apply NMF to fold recognition and remote homolog detection problems. Recent studies have shown that combining support vector machines (SVM with profile-profile alignments improves performance of fold recognition and remote homolog detection remarkably. However, it is not clear which parts of sequences are essential for the performance improvement. Results The performance of fold recognition and remote homolog detection using NMF features is compared to that of the unmodified profile-profile alignment (PPA features by estimating Receiver Operating Characteristic (ROC scores. The overall performance is noticeably improved. For fold recognition at the fold level, SVM with NMF features recognize 30% of homolog proteins at > 0.99 ROC scores, while original PPA feature, HHsearch, and PSI-BLAST recognize almost none. For detecting remote homologs that are related at the superfamily level, NMF features also achieve higher performance than the original PPA features. At > 0.90 ROC50 scores, 25% of proteins with NMF features correctly detects remotely related proteins, whereas using original PPA features only 1% of proteins detect remote homologs. In addition, we investigate the effect of number of positive training examples and the number of basis vectors on performance improvement. We also analyze the ability of NMF to extract essential features by comparing NMF basis vectors with functionally important sites and structurally conserved regions of proteins. The results show that NMF basis vectors have significant overlap with functional sites from PROSITE and with structurally conserved regions from the multiple structural alignments generated by MUSTANG. The correlation between NMF basis vectors and biologically essential parts of proteins supports our conjecture that NMF basis vectors can explicitly represent important sites of proteins. Conclusion The present work demonstrates that applying NMF to profile-profile alignments can reveal essential features of proteins and that these features significantly improve the performance of fold recognition and remote homolog detection.

Lee Soo-Young

2008-07-01

316

Detection of mesoscale zones of atmospheric instabilities using remote sensing and weather forecasting model data  

Science.gov (United States)

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.

Winnicki, I.; Jasinski, J.; Kroszczynski, K.; Pietrek, S.

2009-04-01

317

Automated detection of snow avalanche deposits: segmentation and classification of optical remote sensing imagery  

Science.gov (United States)

Snow avalanches in mountainous areas pose a significant threat to infrastructure (roads, railways, energy transmission corridors), personal property (homes) and recreational areas as well as for lives of people living and moving in alpine terrain. The impacts of snow avalanches range from delays and financial loss through road and railway closures, destruction of property and infrastructure, to loss of life. Avalanche warnings today are mainly based on meteorological information, snow pack information, field observations, historically recorded avalanche events as well as experience and expert knowledge. The ability to automatically identify snow avalanches using Very High Resolution (VHR) optical remote sensing imagery has the potential to assist in the development of accurate, spatially widespread, detailed maps of zones prone to avalanches as well as to build up data bases of past avalanche events in poorly accessible regions. This would provide decision makers with improved knowledge of the frequency and size distributions of avalanches in such areas. We used an object-oriented image interpretation approach, which employs segmentation and classification methodologies, to detect recent snow avalanche deposits within VHR panchromatic optical remote sensing imagery. This produces avalanche deposit maps, which can be integrated with other spatial mapping and terrain data. The object-oriented approach has been tested and validated against manually generated maps in which avalanches are visually recognized and digitized. The accuracy (both users and producers) are over 0.9 with errors of commission less than 0.05. Future research is directed to widespread testing of the algorithm on data generated by various sensors and improvement of the algorithm in high noise regions as well as the mapping of avalanche paths alongside their deposits.

Lato, M. J.; Frauenfelder, R.; Bühler, Y.

2012-09-01

318

Automated detection of snow avalanche deposits: segmentation and classification of optical remote sensing imagery  

Directory of Open Access Journals (Sweden)

Full Text Available Snow avalanches in mountainous areas pose a significant threat to infrastructure (roads, railways, energy transmission corridors, personal property (homes and recreational areas as well as for lives of people living and moving in alpine terrain. The impacts of snow avalanches range from delays and financial loss through road and railway closures, destruction of property and infrastructure, to loss of life. Avalanche warnings today are mainly based on meteorological information, snow pack information, field observations, historically recorded avalanche events as well as experience and expert knowledge. The ability to automatically identify snow avalanches using Very High Resolution (VHR optical remote sensing imagery has the potential to assist in the development of accurate, spatially widespread, detailed maps of zones prone to avalanches as well as to build up data bases of past avalanche events in poorly accessible regions. This would provide decision makers with improved knowledge of the frequency and size distributions of avalanches in such areas. We used an object–oriented image interpretation approach, which employs segmentation and classification methodologies, to detect recent snow avalanche deposits within VHR panchromatic optical remote sensing imagery. This produces avalanche deposit maps, which can be integrated with other spatial mapping and terrain data. The object-oriented approach has been tested and validated against manually generated maps in which avalanches are visually recognized and digitized. The accuracy (both users and producers are over 0.9 with errors of commission less than 0.05. Future research is directed to widespread testing of the algorithm on data generated by various sensors and improvement of the algorithm in high noise regions as well as the mapping of avalanche paths alongside their deposits.

M. J. Lato

2012-09-01

319

Electromagnetic material changes for remote detection and monitoring: a feasibility study: Progress report  

Energy Technology Data Exchange (ETDEWEB)

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.

McCloy, John S.; Jordan, David V.; Kelly, James F.; McMakin, Douglas L.; Johnson, Bradley R.; Campbell, Luke W.

2009-09-01

320

Multifunctional fiber-optic microwave links based on remote heterodyne detection  

DEFF Research Database (Denmark)

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 addition to transparency. All of these three functionalities are presented and experimentally demonstrated with an RHD link based on a dual-frequency laser transmitter with two offset phase-locked semiconductor lasers. In the modulating link, a 1-Gb/s baseband signal is QPSK modulated onto a 9-GHz RF carrier. The frequency converting link demonstrates up-conversion of a 100-Mb/s PSK signal from a 2-GHz 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

Gliese, Ulrik Bo; Nielsen, Torben Nørskov

1998-01-01

 
 
 
 
321

Remote detection of magmatic water in Bullialdus crater on the Moon  

Science.gov (United States)

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.

Klima, Rachel; Cahill, John; Hagerty, Justin J.; Lawrence, David

2013-01-01

322

PET/CT and 3-T whole-body MRI in the detection of malignancy in treated oropharyngeal and hypopharyngeal carcinoma  

International Nuclear Information System (INIS)

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.)

2011-06-01

323

PET/CT and 3-T whole-body MRI in the detection of malignancy in treated oropharyngeal and hypopharyngeal carcinoma  

Energy Technology Data Exchange (ETDEWEB)

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.)

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

324

Automated object-based change detection for forest monitoring by satellite remote sensing : applications in temperate and tropical regions/  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Forest ecosystems have recently received worldwide attention due to their biological diversity and their major role in the global carbon balance. Detecting forest cover change is crucial for reporting forest status and assessing the evolution of forested areas. However, existing change detection approaches based on satellite remote sensing are not quite appropriate to rapidly process the large volume of earth observation data. Recent advances in image segmentation have led to new opportunitie...

Descle?e, Baudouin

2007-01-01

325

Diagnostic accuracy of stress myocardial perfusion MRI and late gadolinium-enhanced MRI for detecting flow-limiting coronary artery disease: a multicenter study  

International Nuclear Information System (INIS)

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 ? 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 (? = 0.70). Stress-rest myocardial perfusion MRI is an accurate diagnostic test for identifying patients with obstructive CAD. (orig.)

2008-12-01

326

Long-term functional outcome after stroke: the impact of MRI-detected lesion characteristics  

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The objective of this thesis was to gain a better understanding of the relationship between ischemic lesion characteristics and long-term functional outcome of stroke survivors. The relationship between volume and localization of the ischemic cerebral lesion and the long-term functional outcome of first-ever ischemic middle cerebral artery stroke survivors was studied. Volume and localization was obtained with conventional Magnetic Resonance Imaging (MRI) scans. Outcome was assessed at the le...

2007-01-01

327

Clustering of Dependent Components: A New Paradigm for fMRI Signal Detection  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Exploratory data-driven methods such as unsupervised clustering and independent component analysis (ICA) are considered to be hypothesis-generating procedures and are complementary to the hypothesis-led statistical inferential methods in functional magnetic resonance imaging (fMRI). Recently, a new paradigm in ICA emerged, that of finding “clusters” of dependent components. This intriguing idea found its implementation into two new ICA algorithms: tree-dependent an...

2005-01-01

328

Detection of seeds in citrus using MRI under motion conditions and improvement with motion correction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Magnetic resonance imaging (MRI) is studied under an online strategy. Axial FLASH images (780 ms acquisition time) have been analyzed to identify seed-containing oranges conveyed at 50 and 100 mm/s through a 4.7 Tesla spectrometer. Developed algorithms enable an automated identification of oranges with more than one seed, though axial images under motion conditions suffer from significant blurring artifacts. To overcome this hindrance, coronal FLASH images have been acquired (279 ms acquisiti...

Herna?ndez Sa?nchez, Natalia; Barreiro Elorza, Pilar; Ruiz Altisent, Margarita; Ruiz Cabello Osuna, Jesus Maria; Fernandez Valle, M. Encarnacion

2005-01-01

329

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.)

2010-09-01

330

Detection of multifocal osteonecrosis in an adolescent with dermatomyositis using whole-body MRI  

Energy Technology Data Exchange (ETDEWEB)

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.)

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

331

Using Automated Morphometry to Detect Associations Between ERP Latency and Structural Brain MRI in Normal Adults  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Despite the clinical significance of event-related potential (ERP) latency abnormalities, little attention has focused on the anatomic substrate of latency variability. Volume conduction models do not identify the anatomy responsible for delayed neural transmission between neural sources. To explore the anatomic substrate of ERP latency variability in normal adults using automated measures derived from magnetic resonance imaging (MRI), ERPs were recorded in the visual three-stimulus oddball t...

2005-01-01

332

Automated detection of brain atrophy patterns based on MRI for the prediction of Alzheimer's disease  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Subjects with mild cognitive impairment (MCI) have an increased risk to develop Alzheimer's disease (AD). Voxel-based MRI studies have demonstrated that widely distributed cortical and subcortical brain areas show atrophic changes in MCI, preceding the onset of AD-type dementia. Here we developed a novel data mining framework in combination with three different classifiers including support vector machine (SVM), Bayes statistics, and voting feature intervals (VFI) to derive a quantitative ind...

Plant, Claudia; Teipel, Stefan J.; Oswald, Annahita; Bo?hm, Christian; Meindl, Thomas; Mourao-miranda, Janaina; Bokde, Arun W.; Hampel, Harald; Ewers, Michael

2010-01-01

333

A method for detecting the temporal sequence of muscle activation during cycling using MRI  

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Surface electromyography (EMG) can assess muscle recruitment patterns during cycling, but has limited applicability to studies of deep muscle recruitment and electrically stimulated contractions. We determined whether muscle recruitment timing could be inferred from MRI-measured transverse relaxation time constant (T2) changes and a cycle ergometer modified to vary power as a function of pedal angle. Six subjects performed 6 min of single-leg cycling under two conditions (E0°-230° and E90°...

Elder, Christopher P.; Cook, Ryan N.; Wilkens, Kenneth L.; Chance, Marti A.; Sanchez, Otto A.; Damon, Bruce M.

2011-01-01

334

Influence of imaging and histological factors on prostate cancer detection and localisation on multiparametric MRI: a prospective study  

Energy Technology Data Exchange (ETDEWEB)

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.)

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

335

Checkmark: a sign for the detection of iliopsoas pathology on MRI of the hip  

International Nuclear Information System (INIS)

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

2010-06-01

336

Checkmark: a sign for the detection of iliopsoas pathology on MRI of the hip  

Energy Technology Data Exchange (ETDEWEB)

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

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

337

Oral manganese as an MRI contrast agent for the detection of nociceptive activity.  

Science.gov (United States)

The ability of divalent manganese to enter neurons via calcium channels makes manganese an excellent MRI contrast agent for the imaging of nociception, the afferent neuronal encoding of pain perception. There is growing evidence that nociceptive neurons possess increased expression and activity of calcium channels, which would allow for the selective accumulation of manganese at these sites. In this study, we show that oral manganese chloride leads to increased enhancement of peripheral nerves involved in nociception on T(1)-weighted MRI. Oral rather than intravenous administration was chosen for its potentially better safety profile, making it a better candidate for clinical translation with important applications, such as pain diagnosis, therapy and research. The spared nerve injury (SNI) model of neuropathic pain was used for the purposes of this study. SNI rats were given, sequentially, increasing amounts of manganese chloride (lowest, 2.29 mg/100 g weight; highest, 20.6 mg/100 g weight) with alanine and vitamin D(3) by oral gavage. Compared with controls, SNI rats demonstrated increased signal-to-background ratios on T(1)-weighted fast spin echo MRI, which was confirmed by and correlated strongly with spectrometry measurements of nerve manganese concentration. We also found the difference between SNI and control rats to be greater at 48 h than at 24 h after dosing, indicating increased manganese retention in addition to increased manganese uptake in nociceptive nerves. This study demonstrates that oral manganese is a viable method for the imaging of nerves associated with increased nociceptive activity. PMID:22447731

Jacobs, Kathleen E; Behera, Deepak; Rosenberg, Jarrett; Gold, Garry; Moseley, Michael; Yeomans, David; Biswal, Sandip

2012-04-01

338

Can we detect water stressed areas in forest thanks thermal infrared remote sensing?  

Science.gov (United States)

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 ŕ large champ pour l'estimation de variables de fonctionnement des écosystčmes 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.

Nourtier, Marie; Chanzy, André; Bes, Bernard; Mariotte, Nicolas

2010-05-01

339

Gadolinium-Hematoporphyrin: new potential MRI contrast agent for detection of breast cancer cell line (MCF-7  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Gadolinium-porphyrins have been synthesized and are currently being investigated as magnetic resonance imaging (MRI contrast agents. This study aimed to synthesize Gd-hematoporphyrin and applicate it for in vitro detection of breast cancer cell line (MCF-7. Methods: The naturally occurring porphyrin (hematoporphyrin was inserted with gadolinium (III nitrate hexahydrate to yield Gd-H. T1 relaxation times and signal enhancement of the contrast agents were presented, and the results were compared. UV spectrophotometer measured the attachment of Gd to the cell membrane of MCF-7. Results: Most of gadolinium chloride (GdCl3 was found in the washing solution, indicate that it didn`t fixed to the breast cell membranes during incubation. Gd-DTPA showed some uptake into the MCF-7 cell membranes with incubation, however, its uptake was significantly lower than Gd-H. Conclusion: Good cell memberan uptake of Gd-porphyrin is comparable to controls, indicating selective delivery it to the breast cell line and considerable potency in diagnostic MR imaging for detection of breast cancer. Key Words: Porphyrin, Contrast agent, MRI, Hematoporphyrin, Breast cancer cell (MCF-7

D Shahbazi Gahrouei

2005-09-01

340

Neurological findings and seizure outcome in children with bilateral opercular macrogyric-like changes detected by MRI.  

Science.gov (United States)

The authors studied 10 patients aged between six and 23 years (mean age 14 years 5 months) with magnetic resonance imaging, which detected bilateral 'macrogyric-like' maldevelopment of the insulo-opercular regions. The data confirm that biopercular gyral anomaly, associated with mental retardation, pseudobulbar palsy (cortical or central) and epilepsy, represents an anatomo-clinical syndrome. Nevertheless, a wide clinical spectrum was found varying from pictures correlating with the topography and extent of the MRI-detected anomaly to conditions indicating wider cerebral involvement. Epilepsy, varying greatly in age at onset and severity, consistently influenced the prognosis for five patients with diffuse EEG abnormalities and intractable seizures with falls. Anterior callosotomy relieved such seizures in one case. PMID:1644232

Guerrini, R; Dravet, C; Raybaud, C; Roger, J; Bureau, M; Battaglia, A; Livet, M O; Colicchio, G; Robain, O

1992-08-01

 
 
 
 
341

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

2008-01-01

342

Compact time-resolved remote Raman system for detection of anhydrous and hydrous minerals and ices for planetary exploration  

Science.gov (United States)

The University of Hawaii and NASA Langley Research Center are developing small, compact, and portable remote Raman systems with pulsed lasers for planetary exploration under the Mars Instrument Development Program. The remote Raman instruments developed previously utilized small telescopes with clear apertures of 125 mm and 100 mm diameters and were able to detect water, ice, water bearing minerals, carbon in carbonate form in calcite, magnesite, dolomite, and siderite from a distance of 10 to 50 m under daytime and nighttime conditions. Recently, we significantly reduced the size of our time-resolved (TR) remote Raman system in order to build a compact system suitable for future space missions. This compact time-resolved Raman system was developed by utilizing (i) a regular 85 mm Nikon (F/1.8) lens with a clear aperture of 50 mm as a collection optic, and (ii) a miniature Raman spectrograph that is 1/14th in volume in comparison to the commercial spectrograph used in our previous work. In this paper, we present the TR remote Raman spectra obtained during daytime from various hydrous and anhydrous minerals, water, water-ice, and CO2-ice using this new compact remote Raman system to 50 m radial distance.

Sharma, S. K.; Misra, A. K.; Acosta, T. E.; Lucey, P. G.; Abedin, M. Nurul

2010-04-01

343

Ion probe detection of clusters in a remotely expanding thermal plasma  

International Nuclear Information System (INIS)

The investigation of a remote depositing Ar/NH3/SiH4-fed expanding thermal plasma by means of an ion probe, under high SiH4 flow rate ( ?SiH4>1 sccs) conditions, is reported here. Given the expanding nature of the plasma in the downstream region, a Gaussian-like ion flux radial profile is observed. A peculiar local off-axis ion peak for high ?SiH4 is also observed nearby. A hypothesis for this phenomenon is proposed, on the basis of the plasma chemistry occurring in the downstream region. The local depletion of electrons, being withdrawn by silicon-containing clusters formed at the boundaries between the plasma beam and the background gas, is responsible for the local enhancement of the ion flux. This hypothesis is corroborated by further studies aiming to evaluate the effects of thermophoretic and electrostatic forces on the above-mentioned clusters. The presented work suggests the application of the capacitive probe technique for cluster detection in specific plasma chemistries.

2010-12-01

344

Effect of atmospheric conditions on operation of terahertz systems for remote detection of ionizing materials  

Energy Technology Data Exchange (ETDEWEB)

This study was motivated by a new concept of remote detection of concealed radioactive materials by using a high power terahertz (THz) wave beam, which can be focused in a small spot where the wave electric field exceeds the breakdown threshold. In the presence of seed electrons in such a volume, this focusing can initiate the avalanche breakdown. Typically, an ambient density of free electrons is assumed to be at the level of one particle per cubic centimeter. So, when a breakdown-prone volume is smaller than 1 cm{sup 3}, there should be significant difference between the breakdown rates in the case of presence of additional sources of ionization versus its absence. Since the flux density of gamma rays emitted by radioactive materials rapidly falls with the distance from the source, while the intensity of THz waves also decreases with the distance due to wave attenuation in the atmosphere, it is important to find an optimal location of the breakdown to be initiated for a given distance between a radioactive material and a THz antenna. This problem is analyzed in a given paper with the account for not only atmospheric attenuation of THz waves but also the air turbulence.

Nusinovich, Gregory S.; Kashyn, Dmytro G. [IREAP, University of Maryland, College Park, Maryland 20742-3511 (United States); Tatematsu, Yoshinori; Idehara, Toshitaka [FIR Center, University of Fukui, Fukui 910-8507 (Japan)

2014-01-15

345

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

1995-06-19

346

Using multi-temporal remote sensor imagery to detect earthquake-triggered landslides  

Science.gov (United States)

Landslides are a major type of geohazards claiming thousands of casualties and billions of dollars in property damages every year. Catastrophic landslide activities are often triggered by some extreme events such as earthquakes, excessive precipitations, or volcanic eruptions. Quickly identifying the spatial distribution of landslides induced by these extreme events is crucial for coordinating rescue efforts and planning in situ investigations. In this study, we propose an automated method for detecting the spatial distribution of earthquake-triggered landslides by examining after-event vegetation changes. Central to this method is the use of pre- and post-event remote sensor images covering the same area. Geometric correction and radiometric normalization are performed before deriving a vegetation index from each image. Then, an image differencing procedure is applied to the two derived indices. With the resultant difference image, an initial landslide distribution map is generated by highlighting the pixels with a threshold percentage decrease in the brightness values as a direct result of the image subtraction. The threshold percentage value is interactively determined by using a visual interpretation method. The final landslide distribution map is produced after using a modal filter to suppress boundary errors in the initial map. This method has been implemented in a test site, approximately 30 km from the epicenter of the Sichuan earthquake (7.9 Ms) that struck on 12 May 2008. A pre-event Thematic Mapper image and a post-event Advanced Spaceborne Thermal Emission and Reflection Radiometer scene are used. The thematic accuracy assessment indicates that 90% of the landslides have correctly been mapped. Given the relatively simple procedures and the good mapping accuracy, the image processing and change detection method identified in this study seems to be promising from an operational perspective.

Yang, Xiaojun; Chen, Liding

2010-12-01

347

Radiographically occult femoral and pelvic fractures are not mutually exclusive: a review of fractures detected by MRI following low-energy trauma  

International Nuclear Information System (INIS)

The purpose of this study was to review the MRI examinations of a large group of low-energy trauma patients in whom pelvic MRI had detected radiographically occult fractures, in order to characterize prevailing fracture patterns and determine how often co-existing proximal femoral and pelvic fractures were observed. All patients having pelvic MRI over 5 years were identified. Word-search software selected 269 MRI reports containing the term 'fracture'. Further scrutiny identified 168 with diagnosis of fracture. MRI request and imaging record review identified 102 low-energy trauma cases that had MRI for clinical suspicion of fracture despite normal radiographs. Sixty-six cases were excluded for the following reasons: no expressed clinical suspicion of occult fracture; history suggesting high-energy trauma; skeletal co-morbidity hindering acute fracture identification; interval more than 2 weeks between radiographs and MRI. The 102 study MRI examinations, which employed a limited two-sequence protocol, were reviewed. Any fracture that had not been appreciated on radiographs was recorded and characterized as femoral, pelvic, or co-existing femoral and pelvic fractures. The 102 study cases had a median age of 82 years. The median interval between pelvic radiographs and MRI was 3 days. MRI showed undiagnosed femoral fracture in 48/102 cases (47.1%), sacral fracture in 41/102 (40.2%), and pubic fracture in 55/102 (53.9%). In 11/102 cases (10.8%), MRI showed undiagnosed fractures of both proximal femur and pelvic ring (seven sacral, six pubic bone, two other site fractures). In 10/11 cases with co-existing femoral and pelvic fractures, the femoral fracture was incomplete. Limited pelvic MRI found a high prevalence of radiographically occult femoral and pelvic fractures in low-energy trauma patients, with clinical suspicion of fracture despite normal radiographs. Co-existing occult femoral and pelvic ring fractures were commonly observed, and in such cases, the femoral fracture was likely to be incomplete and multiple pelvic fractures were typically present. (orig.)

2012-09-01

348

Radiographically occult femoral and pelvic fractures are not mutually exclusive: a review of fractures detected by MRI following low-energy trauma  

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The purpose of this study was to review the MRI examinations of a large group of low-energy trauma patients in whom pelvic MRI had detected radiographically occult fractures, in order to characterize prevailing fracture patterns and determine how often co-existing proximal femoral and pelvic fractures were observed. All patients having pelvic MRI over 5 years were identified. Word-search software selected 269 MRI reports containing the term 'fracture'. Further scrutiny identified 168 with diagnosis of fracture. MRI request and imaging record review identified 102 low-energy trauma cases that had MRI for clinical suspicion of fracture despite normal radiographs. Sixty-six cases were excluded for the following reasons: no expressed clinical suspicion of occult fracture; history suggesting high-energy trauma; skeletal co-morbidity hindering acute fracture identification; interval more than 2 weeks between radiographs and MRI. The 102 study MRI examinations, which employed a limited two-sequence protocol, were reviewed. Any fracture that had not been appreciated on radiographs was recorded and characterized as femoral, pelvic, or co-existing femoral and pelvic fractures. The 102 study cases had a median age of 82 years. The median interval between pelvic radiographs and MRI was 3 days. MRI showed undiagnosed femoral fracture in 48/102 cases (47.1%), sacral fracture in 41/102 (40.2%), and pubic fracture in 55/102 (53.9%). In 11/102 cases (10.8%), MRI showed undiagnosed fractures of both proximal femur and pelvic ring (seven sacral, six pubic bone, two other site fractures). In 10/11 cases with co-existing femoral and pelvic fractures, the femoral fracture was incomplete. Limited pelvic MRI found a high prevalence of radiographically occult femoral and pelvic fractures in low-energy trauma patients, with clinical suspicion of fracture despite normal radiographs. Co-existing occult femoral and pelvic ring fractures were commonly observed, and in such cases, the femoral fracture was likely to be incomplete and multiple pelvic fractures were typically present. (orig.)

Szewczyk-Bieda, Magdalena; Thomas, Naveena; Oliver, Thomas Barry [Ninewells Hospital and Medical School, Department of Clinical Radiology, Dundee, Scotland (United Kingdom)

2012-09-15

349

IMAGE PROCESSING AND REMOTE SENSING – A LULC CHANGE DETECTION USING REMOTELY SENSED DATA FOR COIMBATORE DISTRICT, INDIA  

Directory of Open Access Journals (Sweden)

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.

Dr.K. Thanushkodi, Y. Baby Kalpana, M. Sharrath

2012-12-01

350

The diagnostic performance of radiography for detection of osteoarthritis-associated features compared with MRI in hip joints with chronic pain  

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To evaluate the diagnostic performance of radiography for the detection of MRI-detected osteoarthritis-associated features in various articular subregions of the hip joint. Forty-four patients with chronic hip pain (mean age, 63.3 {+-} 9.5 years), who were part of the Hip Osteoarthritis MRI Scoring (HOAMS) cohort, underwent both weight-bearing anteroposterior pelvic radiography and 1.5 T MRI. The HOAMS study was a prospective observational study involving 52 subjects, conducted to develop a semiquantitative MRI scoring system for hip osteoarthritis features. In the present study, eight subjects were excluded because of a lack of radiographic assessment. On radiography, the presence of superior and medial joint space narrowing, superior and inferior acetabular/femoral osteophytes, acetabular subchondral cysts, and bone attrition of femoral head was noted. On MRI, cartilage, osteophytes, subchondral cysts, and bone attrition were evaluated in the corresponding locations. Diagnostic performance of radiography was compared with that of MRI, and the area under curve (AUC) was calculated for each pathological feature. Compared with MRI, radiography provided high specificity (0.76-0.90) but variable sensitivity (0.44-0.78) for diffuse cartilage damage (using JSN as an indirect marker), femoral osteophytes, acetabular subchondral cysts and bone attrition of the femoral head, and a low specificity (0.42 and 0.58) for acetabular osteophytes. The AUC of radiography for detecting overall diffuse cartilage damage, marginal osteophytes, subchondral cysts and bone attrition was 0.76, 0.78, 0.67, and 0.82, respectively. Diagnostic performance of radiography is good for bone attrition, fair for marginal osteophytes and cartilage damage, but poor for subchondral cysts. (orig.)

Xu, Li [Boston University School of Medicine, Quantitative Imaging Center, Department of Radiology, Boston, MA (United States); Beijing Jishuitan Hospital, Department of Radiology, Beijing (China); Hayashi, Daichi; Guermazi, Ali [Boston University School of Medicine, Quantitative Imaging Center, Department of Radiology, Boston, MA (United States); Hunter, David J. [University of Sydney, Department of Medicine, Sydney (Australia); Li, Ling [New England Baptist Hospital, Division of Research, Boston, MA (United States); Winterstein, Anton; Bohndorf, Klaus [Klinikum Augsburg, Department of Radiology, Augsburg (Germany); Roemer, Frank W. [Boston University School of Medicine, Quantitative Imaging Center, Department of Radiology, Boston, MA (United States); Klinikum Augsburg, Department of Radiology, Augsburg (Germany); University of Erlangen, Department of Radiology, Erlangen (Germany)

2013-10-15

351

The diagnostic performance of radiography for detection of osteoarthritis-associated features compared with MRI in hip joints with chronic pain  

International Nuclear Information System (INIS)

To evaluate the diagnostic performance of radiography for the detection of MRI-detected osteoarthritis-associated features in various articular subregions of the hip joint. Forty-four patients with chronic hip pain (mean age, 63.3 ± 9.5 years), who were part of the Hip Osteoarthritis MRI Scoring (HOAMS) cohort, underwent both weight-bearing anteroposterior pelvic radiography and 1.5 T MRI. The HOAMS study was a prospective observational study involving 52 subjects, conducted to develop a semiquantitative MRI scoring system for hip osteoarthritis features. In the present study, eight subjects were excluded because of a lack of radiographic assessment. On radiography, the presence of superior and medial joint space narrowing, superior and inferior acetabular/femoral osteophytes, acetabular subchondral cysts, and bone attrition of femoral head was noted. On MRI, cartilage, osteophytes, subchondral cysts, and bone attrition were evaluated in the corresponding locations. Diagnostic performance of radiography was compared with that of MRI, and the area under curve (AUC) was calculated for each pathological feature. Compared with MRI, radiography provided high specificity (0.76-0.90) but variable sensitivity (0.44-0.78) for diffuse cartilage damage (using JSN as an indirect marker), femoral osteophytes, acetabular subchondral cysts and bone attrition of the femoral head, and a low specificity (0.42 and 0.58) for acetabular osteophytes. The AUC of radiography for detecting overall diffuse cartilage damage, marginal osteophytes, subchondral cysts and bone attrition was 0.76, 0.78, 0.67, and 0.82, respectively. Diagnostic performance of radiography is good for bone attrition, fair for marginal osteophytes and cartilage damage, but poor for subchondral cysts. (orig.)

2013-10-01

352

Comparison of neuroendocrine tumor detection and characterization using DOTATOC-PET in correlation with contrast enhanced CT and delayed contrast enhanced MRI  

International Nuclear Information System (INIS)

Purpose: We evaluated the rate of successful characterization of gastroenteropancreatic neuroendocrine tumors (NETs) present with an increased somatostatin receptor, comparing CE-CT with CE-MRI, each in correlation with DOTATOC-PET. Methods and materials: 8 patients with GEP-NET were imaged using CE-MRI (Gd-EOB-DTPA), CE-CT (Imeron 400) and DOTATOC-PET. Contrast-enhancement of normal liver-tissue and metastasis was quantified with ROI-technique. Tumor delineation was assessed with visual-score in blind-read-analysis by two experienced radiologists. Results: Out of 40 liver metastases in patients with NETs, all were detected by CE-MRI and the lesion extent could be adequately assessed, whereas CT failed to detect 20% of all metastases. The blind-read-score of CT in arterial and portal phase was median ?0.65 and ?1.4, respectively, and 2.7 for delayed-MRI. The quantitative ROI-analysis presented an improved contrast-enhancement-ratio with a median of 1.2, 1.6 and 3.3 for CE-CT arterial, portal-phase and delayed-MRI respectively. Conclusion: Late CE-MRI was superior to CE-CT in providing additionally morphologic characterization and exact lesion extension of hepatic metastases from neuroendocrine tumor detected with DOTATOC-PET. Therefore, late enhanced Gd-EOB-DTPA-MRI seems to be the adequate imaging modality for combination with DOTATOC-PET to provide complementary (macroscopic and molecular) tumor characterization in hepatic metastasized NETs

2012-10-01

353

Comparison of neuroendocrine tumor detection and characterization using DOTATOC-PET in correlation with contrast enhanced CT and delayed contrast enhanced MRI  

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Purpose: We evaluated the rate of successful characterization of gastroenteropancreatic neuroendocrine tumors (NETs) present with an increased somatostatin receptor, comparing CE-CT with CE-MRI, each in correlation with DOTATOC-PET. Methods and materials: 8 patients with GEP-NET were imaged using CE-MRI (Gd-EOB-DTPA), CE-CT (Imeron 400) and DOTATOC-PET. Contrast-enhancement of normal liver-tissue and metastasis was quantified with ROI-technique. Tumor delineation was assessed with visual-score in blind-read-analysis by two experienced radiologists. Results: Out of 40 liver metastases in patients with NETs, all were detected by CE-MRI and the lesion extent could be adequately assessed, whereas CT failed to detect 20% of all metastases. The blind-read-score of CT in arterial and portal phase was median ?0.65 and ?1.4, respectively, and 2.7 for delayed-MRI. The quantitative ROI-analysis presented an improved contrast-enhancement-ratio with a median of 1.2, 1.6 and 3.3 for CE-CT arterial, portal-phase and delayed-MRI respectively. Conclusion: Late CE-MRI was superior to CE-CT in providing additionally morphologic characterization and exact lesion extension of hepatic metastases from neuroendocrine tumor detected with DOTATOC-PET. Therefore, late enhanced Gd-EOB-DTPA-MRI seems to be the adequate imaging modality for combination with DOTATOC-PET to provide complementary (macroscopic and molecular) tumor characterization in hepatic metastasized NETs.

Giesel, F.L., E-mail: f.giesel@dkfz.de [Department of Nuclear Medicine, University Hospital Heidelberg, INF 400, 69120 Heidelberg (Germany); Kratochwil, C., E-mail: Clemens.kratochwil@t-online.de [Department of Nuclear Medicine, University Hospital Heidelberg, INF 400, 69120 Heidelberg (Germany); Mehndiratta, A., E-mail: dramit.mehndiratta@gmail.com [Keble College, Institute of Biomedical Engineering, University of Oxford, Parks Road, Oxford OX13PG (United Kingdom); Wulfert, S., E-mail: sarah.wulfert@googlemail.com [Department of Nuclear Medicine, University Hospital Heidelberg, INF 400, 69120 Heidelberg (Germany); Moltz, J.H., E-mail: Jan.Moltz@mevis.fraunhofer.de [Fraunhofer MEVIS, Bremen (Germany); Zechmann, C.M., E-mail: christian.zechmann@med.uni-heidelberg.de [Department of Nuclear Medicine, University Hospital Heidelberg, INF 400, 69120 Heidelberg (Germany); Kauczor, H.U., E-mail: Hans-ulrich.kauczor@med.uni-heidelberg.de [Department of Diagnostic and Interventional Radiology, University of Heidelberg, INF 110, 69120 Heidelberg (Germany); Haberkorn, U., E-mail: uwe.haberkorn@med.uni-heidelberg.de [Department of Nuclear Medicine, University Hospital Heidelberg, INF 400, 69120 Heidelberg (Germany); Ley, S., E-mail: ley@gmx.de [Department of Diagnostic and Interventional Radiology, University of Heidelberg, INF 110, 69120 Heidelberg (Germany); Department of Medical Imaging, Toronto General Hospital (Canada)

2012-10-15

354

Probability of malignancy for lesions detected on breast MRI: a predictive model incorporating BI-RADS imaging features and patient characteristics  

International Nuclear Information System (INIS)

To predict the probability of malignancy for MRI-detected breast lesions with a multivariate model incorporating patient and lesion characteristics. Retrospective review of 2565 breast MR examinations from 1/03-11/06. BI-RADS 3, 4 and 5 lesions initially detected on MRI for new cancer or high-risk screening were included and outcomes determined by imaging, biopsy or tumor registry linkage. Variables were indication for MRI, age, lesion size, BI-RADS lesion type and kinetics. Associations with malignancy were assessed using generalized estimating equations and lesion probabilities of malignancy were calculated. 855 lesions (155 malignant, 700 benign) were included. Strongest associations with malignancy were for kinetics (washout versus persistent; OR 4.2, 95% CI 2.5-7.1) and clinical indication (new cancer versus high-risk screening; OR 3.0, 95% CI 1.7-5.1). Also significant were age > = 50 years, size > = 10 mm and lesion-type mass. The most predictive model (AUC 0.70) incorporated indication, size and kinetics. The highest probability of malignancy (41.1%) was for lesions on MRI for new cancer, > = 10 mm with washout. The lowest (1.2%) was for lesions on high-risk screening, <10 mm with persistent kinetics. A multivariate model shows promise as a decision support tool in predicting malignancy for