WorldWideScience

Sample records for remote detection mri

  1. Remote NMR/MRI detection of laser polarized gases

    Science.gov (United States)

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

    2006-06-13

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

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

    Science.gov (United States)

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

    2014-12-01

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

  3. Time-of-flight remote detection MRI of thermally modified wood

    Science.gov (United States)

    Telkki, Ville-Veikko; Saunavaara, Jani; Jokisaari, Jukka

    2010-01-01

    We demonstrate that time-of-flight (TOF) remote detection (RD) magnetic resonance imaging (MRI) provides detailed information about physical changes in wood due to thermal modification that is not available with conventional nuclear magnetic resonance (NMR) based techniques. In the experiments, xenon gas was forced to flow through Pinus sylvestris pine wood samples, and the flow paths and dispersion of gas atoms were observed by measuring 129Xe TOF RD MRI images from the samples. MRI sensitivity of xenon was boosted by the spin exchange optical pumping (SEOP) method. Two different samples were studied: a reference sample, dried at low temperature, and a modified sample, which was thermally modified at 240 °C after the drying. The samples were taken next to each other from the same wood plank in order to ensure the comparability of the results. The most important conclusion is that both the smaller dispersion observed in all the TOF RD experiments independent of each other and the decreased amount of flow paths shown by the time projection of z-encoded TOF RD MRI experiment imply that a large amount of pits connecting tracheid cells are closed in thermal modification. Closed pits may be one reason for reduced moisture content and improved dimensional stability of wood achieved in thermal modification. This is the first time biological samples have been investigated by TOF RD MRI.

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

    Science.gov (United States)

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

    2014-10-16

    Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI) may be employed as noninvasive measurements yielding detailed information about the chemical and physical parameters that define microscale flows. Despite these advantages, magnetic resonance has been difficult to combine with microfluidics, largely due to its low sensitivity when detecting small sample volumes and the difficulty of efficiently addressing individual flow pathways for parallel measurements without utilizing large electric currents to create pulsed magnetic field gradients. Here, we demonstrate that remotely-detected MRI (RD-MRI) employing static magnetic field gradients produced by thin magnetic films can be used to encode flow and overcome some of these limitations. We show how flow path and history can be selected through the use of these thin film labels and through the application of synchronized, frequency-selective pulses. This obviates the need for large electric currents to produce pulsed magnetic field gradients and may allow for further application of NMR and MRI experiments on microscale devices. PMID:25462957

  5. Compressive sampling with prior information in remotely detected MRI of microfluidic devices

    Science.gov (United States)

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

    2012-03-01

    The design and operation of microfluidic analytical devices depends critically on tools to probe microscale chemistry and flow dynamics. Magnetic resonance imaging (MRI) seems ideally suited to this task, but its sensitivity is compromised because the fluid-containing channels in "lab on a chip" devices occupy only a small fraction of the enclosing detector's volume; as a result, the few microfluidic applications of NMR have required custom-designed chips harboring many detectors at specific points of interest. To overcome this limitation, we have developed remotely detected microfluidic MRI, in which an MR image is stored in the phase and intensity of each analyte's NMR signal and sensitively detected by a single, volume-matched detector at the device outflow, and combined it with compressed sensing for rapid image acquisition. Here, we build upon our previous work and introduce a method that incorporates our prior knowledge of the microfluidic device geometry to further decrease acquisition times. We demonstrate its use in multidimensional velocimetric imaging of a microfluidic mixer, acquiring microscopically detailed images 128 times faster than is possible with conventional sampling. This prior information also informs our choice of sampling schedule, resulting in a scheme that is optimized for a specific flow geometry. Finally, we test our approach in synthetic data and explore potential reconstruction errors as a function of optimization and reconstruction parameters.

  6. Quantifying the Diffusion of a Fluid through Membranes by Remote Detection MRI

    International Nuclear Information System (INIS)

    We present a method to measure self-diffusion across membranes without the need for concentration or pressure gradients. Hyperpolarized xenon in combination with remote detection of NMR allows the measurement of membrane permeation, even in the gas phase. The resulting images allow quantification of the amount of fluid diffused through the membrane, and represent an alternative, potentially more precise way of measuring a membrane diffusion coefficient. The use of remote detection of NMR allows for non-invasive signal encoding coupled to sensitive detection, making this approach ideal for the study of diffusion in intact devices such as fuel cells or separation systems

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-10-24

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

  8. Functional MRI in Prostate Cancer Detection

    OpenAIRE

    Sandeep Sankineni; Murat Osman; Peter L. Choyke

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Muller Leah

    2012-06-01

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

  10. Remote Detection via Quantum Coherence

    Science.gov (United States)

    Scully, Marlan

    2015-03-01

    There is nothing so practical as basic science. As a case in point, the compelling need for standoff detection of hazardous gases and vapor indicators of explosives has motivated the development of remotely pumped, scheme(s) which produce radiation in the backward direction [Science, 331(6016), 442-445 (2011); PRX, 3, 041001 (2013)]. Moving from conceptualization to theoretical analysis and experimental verification, we demonstrate that high gain can be achieved in air. Backward air lasing provides new possibilities for remote detection [Laser Phys. Lett., 8(10), 736-741 (2011)]. We gratefully acknowledge support of the National Science Foundation Grants PHY-1241032 and EEC-0540832 and the Robert A. Welch Foundation (Award A-1261).

  11. MRI for troubleshooting detection of prostate cancer

    International Nuclear Information System (INIS)

    Prostate cancer is the most common malignancy in males. Men aged 50 and older are recommended to undergo an annual digital rectal examination (DRE) and determination of prostate-specific antigen (PSA) in serum for early detection. However, prostate biopsies guided by transrectal ultrasound (TRUS) come up negative for cancer in many patients despite having PSA levels above 4 ng/ml. T2-weighted Magnetic Resonance Imaging (MRI) is able to represent the prostate including the surrounding anatomy and depict suspicious areas of low intensity within a high-intensity peripheral zone. MRI has a higher sensitivity for detecting prostate carcinomas than DRE and TRUS in patients having an elevated PSA value and a negative core biopsy. However, its specificity is poor since other abnormalities such as prostatic intraepithelial neoplasia (PIN), prostatitis, scars, or haemmorrhage have a similar MRI appearance. The use of additional techniques such as MR spectroscopy and contrast-enhanced dynamic MRI improves sensitivity, but in particular it improves the specificity of tumor detection. Newly developed biopsy devices enable the performance of targeted biopsies in areas that appear suspicious in the MRI. (orig.)

  12. 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.)

  13. Asymptomatic cerebral hemorrhage detected by MRI

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Yumi; Ohsuga, Hitoshi; Yamamoto, Masahiro; Shinohara, Yukito (Tokai Univ., Isehara, Kanagawa (Japan). School of Medicine)

    1991-03-01

    Detection of previous cerebral infarction on CT films of patients with no history of stroke is a common occurrence. The incidence of silent cerebral infarction was reported to be about 10 to 11 percent, but very few reports concerning asymptomatic cerebral hemorrhage available. However, recent clinical application of MRI has resulted in the detection of old asymptomatic hemorrhage in patients with no history known stroke-like episodes. The purpose of this study was to elucidate the incidence, the cause and the character of the asymptomatic cerebral hemorrhage among patients who had undergone MRI examinations. From September 1987 through June 1990, 2757 patients have undergone 3474 MR scans of the brain with 1.0 Tesla Siemens Magneton unit in our hospital. Seventeen patients showed no clinical signs or symptoms suggesting a stroke episode corresponding to the detected hemorrhagic lesion. The 17 patients corresponded to 0.6% of the patients who underwent MRI, 1.5% of the patients with cerebrovascular disease and 9.5% of the patients with intracerebral hemorrhage(ICH), which was rather higher than expected. Among the 17 patients, 12 were diagnosed as primary ICH and 5 as secondary ICH. Most of the primary asymptomatic hemorrhage were hypertensive ones and slit-like curvilinear lesions between the putamen and claustrum or external capsule. The secondary asymptomatic hemorrhage were due to AVM and angiomas in the frontal cortex, thalamus and pons. (author).

  14. ??????????????????MRI?????

    Directory of Open Access Journals (Sweden)

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    2013-12-01

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

  15. MRI for the detection of anorectal fistulas

    International Nuclear Information System (INIS)

    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.)

  16. 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.)

  17. Website Detection Using Remote Traffic Analysis

    CERN Document Server

    Gong, Xun; Schear, Nabíl; Borisov, Nikita

    2011-01-01

    Recent work in traffic analysis has shown that traffic patterns leaked through side channels can be used to recover important semantic information. For instance, attackers can find out which website, or which page on a website, a user is accessing simply by monitoring the packet size distribution. We show that traffic analysis is even a greater threat to privacy than previously thought by introducing a new attack that can be carried out remotely. In particular, we show that, to perform traffic analysis, adversaries do not need to directly observe the traffic patterns. Instead, they can gain sufficient information by sending probes from a far-off vantage point that exploits a queuing side channel in routers. To demonstrate the threat of such remote traffic analysis, we study a remote website detection attack that works against home broadband users. Because the remotely observed traffic patterns are more noisy than those obtained using previous schemes based on direct local traffic monitoring, we take a dynamic...

  18. Magnetic resonance imaging of living systems by remote detection

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-10-29

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

  19. Role of MRI for detection and characterization of pulmonary nodules

    International Nuclear Information System (INIS)

    Due to physical and technical limitations, magnetic resonance imaging (MRI) has hitherto played only a minor role in image-based diagnostics of the lungs. However, as a consequence of important methodological developments during recent years, MRI has developed into a technically mature and clinically well-proven method for specific pulmonary questions. The purpose of this article is to provide an overview on the currently available sequences and techniques for assessment of pulmonary nodules and analyzes the clinical significance according to the current literature. The main focus is on the detection of lung metastases, the detection of primary pulmonary malignancies in high-risk individuals and the differentiation between pulmonary nodules of benign and malignant character. The MRI technique has a sensitivity of approximately 80 % for detection of malignant pulmonary nodules compared to the reference standard low-dose computed tomography (CT) and is thus somewhat inferior to CT. Advantages of MRI on the other hand are a higher specificity in differentiating malignant and benign pulmonary nodules and the absence of ionizing radiation exposure. A systematic use of MRI as a primary tool for detection and characterization of pulmonary nodules is currently not recommended due to insufficient data. The diagnostic potential of MRI for early detection and staging of malignant pulmonary diseases, however, seems promising. Therefore, further evaluation of MRI as a secondary imaging modality in clinical trials is highly warranted. (orig.)

  20. 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

  1. SQUID-detected ultra-low field MRI

    Science.gov (United States)

    Espy, Michelle; Matlashov, Andrei; Volegov, Petr

    2013-04-01

    MRI remains the premier method for non-invasive imaging of soft-tissue. Since the first demonstration of ULF MRI the trend has been towards ever higher magnetic fields. This is because the signal, and efficiency of Faraday detectors, increases with ever higher magnetic fields and corresponding Larmor frequencies. Nevertheless, there are many compelling reasons to continue to explore MRI at much weaker magnetic fields, the so-called ultra-low field or (ULF) regime. In the past decade many excellent proof-of-concept demonstrations of ULF MRI have been made. These include combined MRI and magnetoencephalography, imaging in the presence of metal, unique tissue contrast, and implementation in situations where a high magnetic field is simply impractical. These demonstrations have routinely used pulsed pre-polarization (at magnetic fields from ?10 to 100 mT) followed by read-out in a much weaker (1-100 ?T) magnetic fields using the ultra-sensitive Superconducting Quantum Interference Device (SQUID) sensor. Even with pre-polarization and SQUID detection, ULF MRI suffers from many challenges associated with lower magnetization (i.e. signal) and inherently long acquisition times compared to conventional >1 T MRI. These are fundamental limitations imposed by the low measurement and gradient fields used. In this review article we discuss some of the techniques, potential applications, and inherent challenges of ULF MRI.

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-08-15

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

  4. Remote Optical Detection of Alpha Radiation

    International Nuclear Information System (INIS)

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

  5. Stress cine MRI for detection of coronary artery disease

    International Nuclear Information System (INIS)

    Stress testing is the cornerstone in the diagnosis of patients with suspected coronary artery disease (CAD). Stress echocardiography has become a well-established modality for the detection of ischemia-induced wall motion abnormalities. However, display and reliable interpretation of stress echocardiography studies are user-dependent, the test reproducibility is low, and 10 to 15% of patients yield suboptimal or non-diagnostic images. Due to its high spatial and contrast resolution, MRI is known to permit an accurate determination of left ventricular function and wall thickness at rest. Early stress MRI studies provided promising results with respect to the detection of CAD. However, the clinical impact was limited due to long imaging time and problematic patient monitoring in the MRI environment. Recent technical improvements - namely ultrafast MR image acquisition - led to a significant reduction of imaging time and improved patient safety. Stress can be induced by physical exercise or pharmacologically by administration of a beta1-agonist (dobutamine) or vasodilatator (dipyridamole and adenosine). The best developed and most promising stress MRI technique is a high-dose dobutamine/atropine stress protocol (10, 20, 30, 40 ?g/kg/min; optionally 0.25-mg fractions of atropine up to maximal dose 1 mg). Severe complications (myocardial infarction, ventricular fibrillation and sustained tachycardia, cardiogenic shock) may be expected in 0.25% of patients. Curray 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.)

  6. Information fusion approach for detection of brain structures in MRI

    Science.gov (United States)

    Shademan, Azad; Soltanian-Zadeh, Hamid

    2002-05-01

    This paper presents an information fusion approach for automatic detection of mid-brain nuclei (caudate, putamen, globus pallidus, and thalamus) from MRI. The method is based on fusion of anatomical information, obtained from brain atlases and expert physicians, into MRI numerical information within a fuzzy framework, employed to model intrinsic uncertainty of problem. First step of this method is segmentation of brain tissues (gray matter, white matter, and cerebrospinal fluid). Physical landmarks such as inter-hemispheric plane alongside numerical information from segmentation step are then used to describe the nuclei. Each nucleus is defined according to a unique description according to physical landmarks and anatomical landmarks, most of which are the previously detected nuclei. Also, a detected nucleus in slice n serves as key landmark to detect same nucleus in slice n+1. These steps construct fuzzy decision maps. Overall decision is made after fusing all of decisions according to a fusion operator. This approach has been implemented to detect caudate, putamen, and thalamus from a sequence of axial T1-weighted brain MRI's. Our experience shows that final nuclei detection results are highly dependent upon primary tissue segmentation. The method is validated by comparing resultant nuclei volumes with those obtained using manual segmentation performed by expert physicians.

  7. Squid detected NMR and MRI at ultralow fields

    Science.gov (United States)

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

    2008-12-16

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

  8. 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 iBOLD' 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 MR

  9. Remote detection and diagnosis of thunderstorm turbulence

    Science.gov (United States)

    Williams, John K.; Sharman, Robert; Craig, Jason; Blackburn, Gary

    2008-08-01

    This paper describes how operational radar, satellite and lightning data may be used in conjunction with numerical weather model data to provide remote detection and diagnosis of atmospheric turbulence in and around thunderstorms. In-cloud turbulence is measured with the NEXRAD Turbulence Detection Algorithm (NTDA) using extensively qualitycontrolled, ground-based Doppler radar data. A real-time demonstration of the NTDA includes generation of a 3-D turbulence mosaic covering the CONUS east of the Rocky Mountains, a web-based display, and experimental uplinks of turbulence maps to en-route commercial aircraft. Near-cloud turbulence is inferred from thunderstorm morphology, intensity, growth rate and environment data provided by (1) satellite radiance measurements, rates of change, winds, and other derived features, (2) lightning strike measurements, (3) radar reflectivity measurements and (4) weather model data. These are combined via a machine learning technique trained using a database of in situ turbulence measurements from commercial aircraft to create a predictive model. This new capability is being developed under FAA and NASA funding to enhance current U.S. and international turbulence decision support systems, allowing rapid-update, highresolution, comprehensive assessments of atmospheric turbulence hazards for use by pilots, dispatchers, and air traffic controllers. It will also contribute to the comprehensive 4-D weather information database for NextGen.

  10. Multiparametric MRI for Localized Prostate Cancer: Lesion Detection and Staging

    OpenAIRE

    Margolis, Daniel J. A.

    2014-01-01

    Multiparametric MRI of the prostate combines high-resolution anatomic imaging with functional imaging of alterations in normal tissue caused by neoplastic transformation for the identification and characterization of in situ prostate cancer. Lesion detection relies on a systematic approach to the analysis of both anatomic and functional imaging using established criteria for the delineation of suspicious areas. Staging includes visual and functional analysis of the prostate “capsule” to deter...

  11. Prostate segmentation on T2 MRI using Optimal Surface Detection

    OpenAIRE

    WU, KE; Garnier, Carole; Shu, Huazhong; Dillenseger, Jean-Louis

    2013-01-01

    This paper deals with a T2 MRI prostate segmentation method. We assume to have an initial surface mesh obtained interactively or after a first rough segmentation. The surface of the prostate is then searched within the initial mesh neighborhood using the Optimal Surface Detection algorithm (OSD). This algorithm is based on the construction of a directed graph from the information obtained around the initial mesh. The optimal surface is then obtained by a graph cut. Three different cost functi...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-10-15

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

  13. 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.)

  14. A low cost fMRI-compatible tracking system using the Nintendo Wii remote.

    Science.gov (United States)

    Modroño, Cristián; Rodríguez-Hernández, Antonio F; Marcano, Francisco; Navarrete, Gorka; Burunat, Enrique; Ferrer, Marta; Monserrat, Raquel; González-Mora, José L

    2011-11-15

    It is sometimes necessary during functional magnetic resonance imaging (fMRI) experiments to capture different movements made by the subjects, e.g. to enable them to control an item or to analyze its kinematics. The aim of this work is to present an inexpensive hand tracking system suitable for use in a high field MRI environment. It works by introducing only one light-emitting diode (LED) in the magnet room, and by receiving its signal with a Nintendo Wii remote (the primary controller for the Nintendo Wii console) placed outside in the control room. Thus, it is possible to take high spatial and temporal resolution registers of a moving point that, in this case, is held by the hand. We tested it using a ball and racket virtual game inside a 3 Tesla MRI scanner to demonstrate the usefulness of the system. The results show the involvement of a number of areas (mainly occipital and frontal, but also parietal and temporal) when subjects are trying to stop an object that is approaching from a first person perspective, matching previous studies performed with related visuomotor tasks. The system presented here is easy to implement, easy to operate and does not produce important head movements or artifacts in the acquired images. Given its low cost and ready availability, the method described here is ideal for use in basic and clinical fMRI research to track one or more moving points that can correspond to limbs, fingers or any other object whose position needs to be known. PMID:21640136

  15. Remote sensing and vegetation stress detection - Problems and progress

    Science.gov (United States)

    Duggin, M. J.; Whitehead, V.

    1983-01-01

    Although considerable progress has been made in applying remote sensing technology to vegetation monitoring, considerable problems still exist in the improvement of techniques for crop type discrimination, stress detection on a large scale, and stress quantification. In this paper, some of the problems remaining in the operational use of remote sensing technology for vegetation stress detection are discussed, and directions in which some of these problems might be solved are proposed.

  16. Development of remote surgical navigation and biopsy needle guidance system using Open-MRI and high-speed network

    Science.gov (United States)

    Okura, Yasuhiko; Matsumura, Yasushi; Kuwata, Shigeki; Takeda, Hiroshi

    2004-05-01

    This study describes a remote surgical guidance and navigation system developed for surgery using "Open-MRI" and high-speed network. We connected Osaka University Hospital and Kawasaki Hospital which has deployed Open- MRI with high speed IP over ATM network. The distance between two hospitals is approximately 50 km. Two video cameras were installed with an angle of 40 degrees on an open-MRI gantry to obtain intraoperative images. Two pairs of CODEC (AD/DA converter) were equipped on the network to transfer both images and sound in real time. A pointer system to indicate a region on an image was also developed. MRI images obtained by Open-MRI were transferred to a 3D workstation in Osaka University Hospital. The system was designed for a senior surgeon in Osaka University to advise regarding accurate needle direction for a remote patient by checking the reconstructed 3D images and schemata shown by the navigation software. The schemata were also superimposed on intraoperative images from two cameras, and the superimposed images were sent back to Kawasaki Hospital. This system allowed a surgeon in the operation room at Kawasaki Hospital to accurately view navigation schema under supervision by a senior surgeon in a remote university hospital with superimposion of intraoperative images. The pointer system allowed both doctors to share intraoperative images during a virtual-real surgical operation. A successful biopsy case using this newly developed system illustrates the effectiveness of this system.

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

    International Nuclear Information System (INIS)

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

  18. FDG-PET Lacks Sufficient Sensitivity to Detect Myxoid Liposarcoma Spinal Metastases Detected by MRI.

    Science.gov (United States)

    Schwab, Joseph H; Healey, John H

    2007-01-01

    Purpose. To document a case of myxoid liposarcoma in which PET scan was less sensitive than MRI in detecting spinal metastasis. Materials and Methods. The case of a 65-year-old female with a history of myxoid liposarcoma (MLS) of the thigh resected 5 years previously and now presenting with low back pain is presented. Her medical oncologist ordered an FDG-PET scan to evaluate distant recurrence. Subsequently, an MRI of her spine was obtained by her surgeon. Results. The FDG-PET scan was obtained 1 week prior to the MRI, and it did not show increased glucose uptake in the spine. Her MRI did show increased signal intensity in her lumbar spine. CT needle biopsy confirmed the lesion to be metastatic MLS. Conclusion. FDG-PET scans are utilized to detect distant recurrence of cancerous lesions. Myxoid liposarcoma has a unique propensity to metastasize to the spine. Previous reports have documented the unreliability of bone scintigraphy to diagnose these metastases. Our report demonstrates that FDG-PET may also lack the sensitivity needed to detect these lesions. We advocate total spine MRI when screening for metastases in this population when they present with back pain. PMID:17641744

  19. FDG-PET Lacks Sufficient Sensitivity to Detect Myxoid Liposarcoma Spinal Metastases Detected by MRI

    Directory of Open Access Journals (Sweden)

    Joseph H. Schwab

    2007-05-01

    Full Text Available Purpose. To document a case of myxoid liposarcoma in which PET scan was less sensitive than MRI in detecting spinal metastasis. Materials and Methods. The case of a 65-year-old female with a history of myxoid liposarcoma (MLS of the thigh resected 5 years previously and now presenting with low back pain is presented. Her medical oncologist ordered an FDG-PET scan to evaluate distant recurrence. Subsequently, an MRI of her spine was obtained by her surgeon. Results. The FDG-PET scan was obtained 1 week prior to the MRI, and it did not show increased glucose uptake in the spine. Her MRI did show increased signal intensity in her lumbar spine. CT needle biopsy confirmed the lesion to be metastatic MLS. Conclusion. FDG-PET scans are utilized to detect distant recurrence of cancerous lesions. Myxoid liposarcoma has a unique propensity to metastasize to the spine. Previous reports have documented the unreliability of bone scintigraphy to diagnose these metastases. Our report demonstrates that FDG-PET may also lack the sensitivity needed to detect these lesions. We advocate total spine MRI when screening for metastases in this population when they present with back pain.

  20. Detection of colorectal liver metastases: a prospective multicenter trial comparing unenhanced MRI, MnDPDP-enhanced MRI, and spiral CT

    OpenAIRE

    Gandini, Giovanni

    2004-01-01

    The aim of this study was to compare unenhanced MRI, MnDPDP-enhanced MRI, and spiral CT in the detection of hepatic colorectal metastases. Forty-four patients with hepatic colorectal metastases were examined with unenhanced and MnDPDP-enhanced MRI and with unenhanced and contrast-enhanced spiral CT. The MR examination protocol included baseline T1-weighted spin-echo (SE), T1-weighted gradient-recalled-echo (GRE), and T2-weighted fast-SE sequences; and T1-weighted SE and T1-weighted GRE sequen...

  1. Target Detection: Remote Sensing Techniques for Defence Applications

    Directory of Open Access Journals (Sweden)

    B. B. Chaudhuri

    1995-10-01

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

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

    OpenAIRE

    Karypis George; Rangwala Huzefa

    2006-01-01

    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 compre...

  3. 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.)

  4. Website Detection Using Remote Traffic Analysis

    OpenAIRE

    Gong, Xun; Kiyavash, Negar; Schear, Nabíl; Borisov, Nikita

    2011-01-01

    Recent work in traffic analysis has shown that traffic patterns leaked through side channels can be used to recover important semantic information. For instance, attackers can find out which website, or which page on a website, a user is accessing simply by monitoring the packet size distribution. We show that traffic analysis is even a greater threat to privacy than previously thought by introducing a new attack that can be carried out remotely. In particular, we show that,...

  5. FDG-PET Lacks Sufficient Sensitivity to Detect Myxoid Liposarcoma Spinal Metastases Detected by MRI

    OpenAIRE

    Schwab, Joseph H.; Healey, John H.

    2007-01-01

    Purpose. To document a case of myxoid liposarcoma in which PET scan was less sensitive than MRI in detecting spinal metastasis. Materials and Methods. The case of a 65-year-old female with a history of myxoid liposarcoma (MLS) of the thigh resected 5 years previously and now presenting with low back pain is presented. Her medical oncologist ordered an FDG-PET scan to evaluate distant recurrence. Subsequently, an MRI of her spine was obtained by her surgeon. Results. The FDG-PET scan was obta...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-06-01

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

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

    Directory of Open Access Journals (Sweden)

    N Panigrahi

    2011-08-01

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

  8. 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 lesionsesions

  9. The method of active remote detection of nuclear ammunition

    International Nuclear Information System (INIS)

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

  10. Two-Dimensional Change Detection Methods Remote Sensing Applications

    CERN Document Server

    Ilsever, Murat

    2012-01-01

    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

  11. Detecting regional changes in myocardial contraction patterns using MRI

    Science.gov (United States)

    Sanchez-Ortiz, Gerardo I.; Chandrashekara, Raghavendra; Rhode, Kawal S.; Razavi, Reza; Hill, Derek L. G.; Rueckert, Daniel

    2004-04-01

    Measuring changes in cardiac motion patterns can assist in diagnosing the onset of arrhythmia and ischaemia and in the follow-up of treatment. This work presents a methodology for measuring such motion changes from MR images. Non-rigid registration is used to track cardiac motion in a sequence of 3D tagged MR images. We use a cylindrical coordinate system to subdivide the myocardium into smaller anatomically meaningful regions and to express motion derived measurements such as displacement and strain for each myocardial region during the cardiac cycle. In the first experiment we have evaluated the proposed methods using synthetic image sequences where the ground truth was available. These images were generated using a cardiac motion simulator for tagged MRI. Normal and abnormal motion fields were produced by modifying parameters in a small region of the myocardium. In the second experiment we have acquired two separate tagged MR image sequences from five healthy volunteers. Both acquisitions have been carried out without moving the volunteer inside the scanner, thus avoiding potential misregistration errors due to subject motion between scans. In addition, one of volunteers was subjected to stress during one of the scans. In the final experiment we acquired tagged MR images from a patient with super-ventricular tachyarrhythmia, before and after radio frequency ablation. The image acquisition and catheter intervention were performed with a combined X-ray and MRI system. Detection results were correct on synthetic data and no region was incorrectly classified as having significant changes in the repetition studies. Significant changes in motion pattern were measured in the stress and ablation studies. Furthermore, results seem to corroborate that the ablation regularised cardiac contraction.

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

    Directory of Open Access Journals (Sweden)

    ???

    2013-04-01

    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.

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

    International Nuclear Information System (INIS)

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

  14. The Remote Detection of Alpha-Radioactive Nucleus Decay

    Science.gov (United States)

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

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-08-15

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

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

    International Nuclear Information System (INIS)

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

  17. Machine learning for real time remote detection

    Science.gov (United States)

    Labbé, Benjamin; Fournier, Jérôme; Henaff, Gilles; Bascle, Bénédicte; Canu, Stéphane

    2010-10-01

    Infrared systems are key to providing enhanced capability to military forces such as automatic control of threats and prevention from air, naval and ground attacks. Key requirements for such a system to produce operational benefits are real-time processing as well as high efficiency in terms of detection and false alarm rate. These are serious issues since the system must deal with a large number of objects and categories to be recognized (small vehicles, armored vehicles, planes, buildings, etc.). Statistical learning based algorithms are promising candidates to meet these requirements when using selected discriminant features and real-time implementation. This paper proposes a new decision architecture benefiting from recent advances in machine learning by using an effective method for level set estimation. While building decision function, the proposed approach performs variable selection based on a discriminative criterion. Moreover, the use of level set makes it possible to manage rejection of unknown or ambiguous objects thus preserving the false alarm rate. Experimental evidences reported on real world infrared images demonstrate the validity of our approach.

  18. Tsunami "shadows" may allow remote detection of tidal waves

    Science.gov (United States)

    Godin

    This resource provides an abstract. This study investigates tsunami shadows, extended dark strips on the ocean surface before a tsunami. Such shadows are found to result from an air-sea interaction induced by tsunami-related atmospheric disturbances. Results suggest that remote surface water observations can be used to detect deep ocean tsunamis via their shadows and thus provide significantly more reliable and earlier warning before the large waves strike vulnerable shores.

  19. 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 essary. 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

  20. Recent developments in remote gas detection using molecular dispersion sensing

    Science.gov (United States)

    Nikodem, Michal

    2014-12-01

    In this paper we study signal amplitude in Chirp-modulated Chirped Laser Dispersion Spectroscopy (CM-CLaDS). CLaDS is a laser-based spectroscopic technique for molecular sensing that uses heterodyne detection to measure optical dispersion caused by molecular transitions. With baseline-free nature and high-immunity to optical power fluctuations CLaDS is well suited to long distance remote, open-path monitoring and stand-off chemical detection. In this work we analyze CM-CLaDS performance. We show that for certain conditions using proper modulation waveform can provide increase in the signal amplitude with respect to previously presented configurations.

  1. Comparison of Ultrasound and MRI in Detecting Fetal Anomalies

    Directory of Open Access Journals (Sweden)

    R. Abdi

    2005-08-01

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

  2. 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?

    International Nuclear Information System (INIS)

    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%/760%/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.

  3. T1-weighted MRI for the detection of coronary artery plaque haemorrhage

    Energy Technology Data Exchange (ETDEWEB)

    Oei, May Lin; Ozgun, Murat; Seifarth, Harald; Bunck, Alexander; Fischbach, Roman; Heindel, Walter; Maintz, David [University of Muenster, Department of Clinical Radiology, Muenster (Germany); Orwat, Stefan [University of Muenster, Department of Cardiology, Muenster (Germany); Botnar, Rene [Biomedical Research Centre of Guy' s, St. Thomas' NHS Foundation Trust, King' s College London, BHF Centre, Division of Imaging Science, London (United Kingdom)

    2010-12-15

    Hyperintense areas in atherosclerotic plaques on pre-contrast T1-weighted MRI have been shown to correlate with intraplaque haemorrhage. We evaluated the presence of T1 hyperintensity in coronary artery plaques in coronary artery disease (CAD) patients and correlated results with multi-detector computed tomography (MDCT) findings. Fifteen patients with CAD were included. Plaques detected by MDCT were categorised based on their Hounsfield number. T1-weighted inversion recovery (IR) MRI prepared coronary MRI for the detection of plaque and steady-state free-precession coronary MR-angiography for anatomical correlation was performed. After registration of MDCT and MRI, regions of interest were defined on MDCT-visible plaques and in corresponding vessel segments acquired with MRI. MDCT density and MR signal measurement were performed in each plaque. Forty-three plaques were identified with MDCT. With IR-MRI 5/43 (12%) plaques were hyperintense, 2 of which were non-calcified and 3 mixed. Average signal-to-noise and contrast-to-noise ratios of hyperintense plaques were 15.7 and 9.1, compared with 5.6 and 1.2 for hypointense plaques. Hyperintense plaques exhibited a significantly lower CT density than hypointense plaques (63.6 vs. 140.8). There was no correlation of plaque signal intensity with degree of stenosis. T1-weighted IR-MRI may be useful for non-invasive detection and characterisation of intraplaque haemorrhage in coronary artery plaques. (orig.)

  4. 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.)

  5. Comparison of MDCT and MRI in the detection and sizing of acute and chronic myocardial infarcts

    Energy Technology Data Exchange (ETDEWEB)

    Choe, Yeon Hyeon [Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Gangnam-Gu, Seoul 135-710 (Korea, Republic of)], E-mail: yhchoe@smc.samsung.co.kr; Choo, Ki Seok [Department of Radiology, Pusan National University Hospital, College of Medicine, Pusan National University, Seoul (Korea, Republic of); Jeon, Eun-Seok; Gwon, Hyeon-Cheol; Choi, Jin-Ho; Park, Jeong-Euy [Division of Cardiology, Department of Internal Medicine, and Cardiac and Vascular Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2008-05-15

    Purpose: This study compared ability of multidetector computed tomography (MDCT) to detect and size the myocardial infarctions (MI) with MRI. Materials and methods: Eighty examination sets of MDCT and MRI of 63 consecutive patients in the acute stage (average 6.3 days, n = 40) and/or chronic stage (average, 11.8 months; n = 40) of reperfused MI were examined in this study. The first-pass and delayed MRI was performed using a 1.5 T scanner with an injection of Gd-DTPA to assess the extent of MI. Within 24 h after MRI, MDCT was performed at the arterial phase around 25 s with a 10-min delay using one of the following scanners: 4-slice, 16-slice, and 40-slice. The volume of the MI over the total myocardial volume was calculated from the MRI and CT images. Results: MDCT revealed MI lesions in all cases except for one (1.3%) on the early phase images. The percentage volume of the lesion on the MDCT images correlated with that of the MR images. The correlation coefficient between perfusion MRI and early CT was 0.62 (p < 0.0001) and the correlation coefficient between the 5-min delay MRI and late CT was 0.81 (p < 0.0001). There was no significant difference in the average lesion volume (%) between perfusion MRI (10.8 {+-} 6.7%) and early CT (12.1 {+-} 8.5%) (p > 0.05), but there was significant difference between the 5-min delay MRI (25.9 {+-} 12.1%) and late CT (22.8 {+-} 11.8%) (p < 0.001). Conclusion: MDCT produces comparable results to MRI in the detection and sizing of acute and chronic MI.

  6. 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)

  7. Whole-body MRI using a rolling table platform for the detection of bone metastases

    International Nuclear Information System (INIS)

    The aim of this study was to compare the results of whole-body MRI using a recently developed rolling table platform with findings of nuclear scintigraphy in patients with bone metastases. Twenty-six patients with known or suspected bone metastases who had undergone radionuclide scintigraphy were examined by MRI. Patients were placed on a rolling table platform with integrated phased-array surface coils [BodySURF (system for unlimited field of view)] capable of pulling the patient through the isocenter of the magnet. Using a five-station approach three different image sets (T1-weighted gradient recalled echo, half-Fourier acquired single-shot turbo spin echo, and short tau inversion recovery) were collected in the coronal plane. In addition, the spine was imaged in the sagittal plane. The MRI findings were compared with the results obtained by scintigraphy. The whole-body MR examination lasting merely 40 min was feasible in all 26 patients. The MRI revealed excellent correlation with scintigraphy regarding metastatic lesions. A total of 60 regions with metastatic lesions were identified on bone scintigraphy. Fifty-three regions were detected on identical locations by MRI. The regions missed by MRI were located mainly in ribs and skull. The MRI could identify additional bone metastases in spine, pelvis, and femur. The MRI screening for bone metastases correlated well with bone scintigraphy. Use of the rolling table platform permits rapid imaging based on three differenmits rapid imaging based on three different contrast mechanisms of the entire skeletal system. (orig.)

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

    International Nuclear Information System (INIS)

    Objective: To Compare the diagnostic value between low dose dobutamine stress transthrotic echocardiography and low dose dobutamine stress MRI in detecting myocardial viability of chronic myocardial infarction. Methods: Rest and low dose dobutamine (5, 10 ?g·kg-1·min-1) stress transthrotic echocardiography and cine-MRI were performed in 30 patients with chronic myocardial infarction. 24 patients underwent successful revascularization and 10 of them underwent another rest cine-MRI study to assess segmental myocardial functional recovery. Left ventricular were divided into 16 segments, the criteria of viability in different techniques is: MRI: dobutamine induced systolic wall thickening was ?2 mm in akinetic or diskinetic segments at rest; Echocardiography: wall motion score reduced at least 1 after dobutamine stress in akinetic or' diskinetic segments at rest. Results: One hundren and eight segments showed wall motion abnormalities of 30 patients, 65 and 56 segments shows positive reaction, 43 and 52 segments shows negativereaction in MRI and echocardiography after dobutamine stress respectively. Kappa value of the two techniques is 0.75, concordance in both techniques is 88%. Twenty-four segments showed functional recovery, 14 segments remained dysfunction 3-6 months after revascularization, the sensitivity, specificity and accuracy of detecting myocardial viability in chronic myocardial infarction in MRI and echocardiography is 95.8% vs 79. and echocardiography is 95.8% vs 79.2% (P>0.05), 85.7% vs 85.7% (P>0.05), 92.1% vs 81.6% (P>0.05) respectively. The sensitivity and accuracy of MRI is a little higher. Conclusion: The ability of detecting myocardial viability by both low dose dobutamine stress transthrotic echocardiography and low dose dobutamine stress MRI is similer, the sensitivity and accuracy of MRI is a little higher. (authors)

  9. Feasibility of Shutter-Speed DCE-MRI for Improved Prostate Cancer Detection

    OpenAIRE

    Li, Xin; Priest, Ryan A.; Woodward, William J.; Tagge, Ian J.; Siddiqui, Faisal; HUANG, WEI; William D. Rooney; Beer, Tomasz M.; Garzotto, Mark G.; Springer, Charles S

    2012-01-01

    The feasibility of Shutter-Speed Model (SSM) (Dynamic-Contrast-Enhanced) DCE-MRI pharmacokinetic analyses for prostate cancer detection was investigated in a pre-biopsy patient cohort. Differences of results from the fast exchange regime-allowed (FXR-a) SSM version and the fast-exchange-limit-constrained (FXL-c) standard model (SM) are demonstrated. Though the spatial information is more limited, post-DCE-MRI biopsy specimens were also examined. The MRI results were correlated with the biopsy...

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

    OpenAIRE

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

    2008-01-01

    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...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1989-07-01

    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.).

  12. Supercooled large drop detection with NASA's Icing Remote Sensing System

    Science.gov (United States)

    Serke, David J.; Reehorst, Andrew L.; Politovich, Marcia K.

    2010-10-01

    In-flight icing occurs when aircraft impact supercooled liquid drops. The supercooled liquid freezes on contact and the accreted ice changes a plane's aerodynamic characteristics, which can lead to dangerous loss of control. NASA's Icing Remote Sensing System consists of a multi-channel radiometer, a laser ceilometer and a vertically-pointing Kaband radar, whos fields are merged with internal software logic to arrive at a hazard classification for in-flight icing. The radiometer is used to derive atmospheric temperature soundings and integrated liquid water and the ceilometer and radar are used to define cloud boundaries. The integrated liquid is then distributed within the determined cloud boundaries and layers to arrive at liquid water content profiles, which if present below freezing are categorized as icing hazards. This work outlines how the derived liquid water content and measured Ka-band reflectivity factor profiles can be used to derive a vertical profile of radar-estimated particle size. This is only possible because NASA's system arrives at independent and non-correlated measures of liquid water and reflectivity factor for a given range volume. The size of the drops significantly effect the drop collection efficiency and the location that icing accretion occurs on the craft's superstructure and thus how a vehicle's performance is altered. Large drops, generally defined as over 50 ?m in diameter, tend to accrete behind the normal ice protected areas of the leading edge of the wing and other control surfaces. The NASA Icing Remote Sensing System was operated near Montreal, Canada for the Alliance Icing Research Study II in 2003 and near Cleveland, Ohio from 2006 onward. In this study, we present case studies to show how NASA's Icing Remote Sensing System can detect and differentiate between no icing, small drop and large drop in-flight icing hazards to aircraft. This new product provides crucial realtime hazard detection capabilities which improve avaiation safety in the near-airport environment with cost-effective, existing instrumentation technologies.

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

    International Nuclear Information System (INIS)

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

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

    DEFF Research Database (Denmark)

    Canty, Morton J.; Nielsen, Allan Aasbjerg

    2005-01-01

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

  15. Whole-body MRI for detecting osseous metastases: comparison with bone scintigraphy

    International Nuclear Information System (INIS)

    Objective: The aim of the study was to evaluate the reliability of whole-body MRI (WB- MRI) in detecting osseous metastases. Methods: Thirty patients verified with malignant tumor by histology were enrolled. All the patients underwent WB-MRI and bone scintigraphy (BS) with a two week interval. Clinical information, conventional MRI and CT images, and follow-up data were collected as gold standard for the diagnosis of bone metastases. The data of 30 patients and 270 segments as study unit respectively were analyzed. The sensitivity and specificity between WB-MRI and BS were compared with McNemar test. Results: Bone metastases were confirmed in 27 of 30 patients by gold standard. Twenty-five patients with bone metastases were detected by WB-MRI and no false-positive cases. Twenty-seven patients with bone metastases were found by BS but having two false-positive cases. With patients as study unit, the diagnostic sensitivity of WB-MRI and BS were both 92.6% (25/27) and the specificity were 100% (3/3) and 33.3% (1/3), respectively. The area under ROC curve of WB-MRI and BS were 0.9630 and 0.6296, respectively (P>0.05). With segments as study unit, 119 bone metastases segments were confirmed. The diagnostic sensitivity of WB-MRI and BS were 90.8% (108/119) and 70.6% (84/119) (P<0.01). while the specificity were 98.0% (148/151) and 90.7% (137/151), respectively (P<0.01). The area under ROC curve of WB-MRI and BS were 0.9438 and 0.8066. The former was obviously higher than the latter (P< 0.01). Meanwhile, by WB-MRI, 3 cases coexisting with brain metastases, 4 cases with lung metastases, and 4 cases with hepatic metastases were found. Conclusion: WB-MRI was a good tool for screening osseous metastases. (authors)

  16. 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 foand rib. WB-MRI was an excellent method for screening bone metastasis, especially the vertebral body. (author)

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

    Directory of Open Access Journals (Sweden)

    Karypis George

    2006-10-01

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

  18. Satellite Remote Sensing Detection of Wastewater Plumes in Southern California

    Science.gov (United States)

    Trinh, R. C.; Holt, B.; Pan, B. J.; Rains, C.; Gierach, M. M.

    2014-12-01

    Wastewater discharged through ocean outfalls can surface near coastlines and beaches, posing a threat to the marine environment and human health. Coastal waters of the Southern California Bight (SCB) are an ecologically important marine habitat and a valuable resource in terms of commercial fishing and recreation. Two of the largest wastewater treatment plants along the U.S. West Coast discharge into the SCB, including the Hyperion Wastewater Treatment Plant (HWTP) and the Orange County Sanitation District (OCSD). In 2006, HWTP conducted an internal inspection of its primary 8 km outfall pipe (60 m depth), diverting treated effluent to a shorter 1.2 km pipe (18 m depth) from Nov. 28 to Nov. 30. From Sep. 11 - Oct. 4, 2012, OCSD conducted a similar diversion, diverting effluent from their 7 km outfall pipe to a shallower 2.2 km pipe, both with similar depths to HWTP. Prevailing oceanographic conditions in the SCB, such as temporally reduced stratification and surface circulation patterns, increased the risk of effluent being discharged from these shorter and shallower pipes surfacing and moving onshore. The aim of this study was to evaluate the capabilities of satellite remote sensing data (i.e., sea surface roughness from SAR, sea surface temperature from MODIS-Aqua and ASTER-Terra, chlorophyll-a and water leaving radiance from MODIS-Aqua) in the identification and tracking of wastewater plumes during the 2006 HWTP and 2012 OCSD diversion events. Satellite observations were combined with in situ, wind, and current data taken during the diversion events, to validate remote sensing techniques and gain surface to subsurface context of the nearshore diversion events. Overall, it was found that satellite remote sensing data were able to detect surfaced wastewater plumes along the coast, providing key spatial information that could inform in situ field sampling during future diversion events, such as the planned 2015 HWTP diversion, and thereby constrain costs.

  19. Experimental demonstration of remote optical detection of trace explosives

    Science.gov (United States)

    Wynn, C. M.; Palmacci, S.; Kunz, R. R.; Zayhowski, J. J.; Edwards, B.; Rothschild, M.

    2008-04-01

    MIT Lincoln Laboratory has developed a concept that could enable remote (10s of meters) detection of trace explosives' residues via a field-portable laser system. The technique relies upon laser-induced photodissociation of nitro-bearing explosives into vibrationally excited nitric oxide (NO) fragments. Subsequent optical probing of the first vibrationally excited state at 236 nm yields narrowband fluorescence at the shorter wavelength of 226 nm. With proper optical filtering, these photons provide a highly sensitive explosives signature that is not susceptible to interference from traditional optical clutter sources (e.g., red-shifted fluorescence). Quantitative measurements of trace residues of TNT have been performed demonstrating this technique using a breadboard system, which relies upon a pulsed optical parametric oscillator (OPO) based laser. Based on these results, performance projections for a fieldable system are made.

  20. Soft Computing Techniques for Change Detection in remotely sensed images : A Review

    OpenAIRE

    Khurana, Madhu; Saxena, Vikas

    2015-01-01

    With the advent of remote sensing satellites, a huge repository of remotely sensed images is available. Change detection in remotely sensed images has been an active research area as it helps us understand the transitions that are taking place on the Earths surface. This paper discusses the methods and their classifications proposed by various researchers for change detection. Since use of soft computing based techniques are now very popular among research community, this pa...

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

    International Nuclear Information System (INIS)

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

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

    CERN Document Server

    Kekre, H B; Gharge, Saylee M

    2010-01-01

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

  3. First report of an accessory popliteal muscle: detection with MRI

    Energy Technology Data Exchange (ETDEWEB)

    Duc, Sylvain R.; Wentz, Klaus U.; Zollikofer, Christoph L. [MR Research Group of the Institute of Diagnostic Radiology, Kantonsspital Winterthur, Brauerstrasse 15, 8401, Winterthur (Switzerland); Kaech, Kurt P. [Department of Trauma Surgery, Kantonsspital Winterthur, Winterthur (Switzerland)

    2004-07-01

    During an MRI examination of the knee in a 48-year-old patient suffering from degenerative changes of a partly resected medial meniscus and concomitant osteoarthritis of the knee joint, an unusual variant of an accessory muscle in the popliteal fossa was found. To our best knowledge this muscle has never been described before. Because of the close relationship to the popliteal muscle with regard to course and localisation in the deep popliteal fossa ventral to the popliteal artery, the term ''accessory popliteal muscle'' is proposed. (orig.)

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.)

  6. Remote Detection of Iodine By using Differential Absorption Lidar

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  8. Vehicle Accident Automatic Detection and Remote Alarm Device

    Directory of Open Access Journals (Sweden)

    Varsha Goud

    2012-06-01

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

  9. A comprehensive system for evaluation of remote sequence similarity detection

    Directory of Open Access Journals (Sweden)

    Kim Bong-Hyun

    2007-08-01

    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/.

  10. Screening applications for MRI in the detection of upper abdominal disease: comparative study of non-contrast-enhanced single-shot MRI and contrast-enhanced helical CT

    International Nuclear Information System (INIS)

    Purpose: To compare the value of 'push-button' singe-shot non-contrast-enhanced MRI and contrast-enhanced helical CT for detection of upper abdominal disease. Methods: In 120 patients, images obtained with non contrast-enhanced single-shot MRI (T2: double echo HASTE, and T1: turbo FLASH) and contrast-enhanced helical CT were compared. Lesions or abnormalities were divided in 8 anatomical categories (1: liver; 2: pancreatobiliary; 3: kidney/adrenal gland; 4: retroperitoneum; 5: vascular; 6: spleen; 7: gastrointestinal tract and peritoneum; 8: base of thorax) and classified as follows: 2: seen at MRI only; 1: better seen at MRI; 0: no difference; -1: better seen at CT; -2: seen at CT only. Also recorded were the 'door-to-door' examination times. Results: Of a total of 629 abnormalities, 594 were detected at MRI (94 %) and 536 at CT (85 %). CT offered better results in two categories only: retroperitoneum (mean score: -0.68) and vascular (mean score -0.87). Mean examination times were 19 min for CT and 14.8 min for MRI. Conclusion: Unenhanced single-shot MRI is a valuable first step of a comprehensive upper abdominal MR exam and may even be the final step in many patients. (orig.)

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-04-15

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

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

    Science.gov (United States)

    Nakhmani, Arie; Kikinis, Ron; Tannenbaum, Allen

    2014-03-01

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

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

    Directory of Open Access Journals (Sweden)

    Weiner Bradley K

    2008-10-01

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

  15. Detection of bone metastasis of prostate cancer. Comparison of whole-body MRI and bone scintigraphy

    International Nuclear Information System (INIS)

    Purpose: prostate cancer continues to be the third leading cancer-related mortality of western men. Early diagnosis of bone metastasis is important for the therapy regime and for assessing the prognosis. The standard method is bone scintigraphy. Whole-body MRI proved to be more sensitive for early detection of skeletal metastasis. However, studies of homogenous tumor entities are not available. The aim of the study was to compare bone scintigraphy and whole-body MRI regarding the detection of bone metastasis of prostate cancer. Materials and methods: 14 patients with histologically confirmed prostate cancer and a bone scintigraphy as well as whole-body MRI within one month were included. The mean age was 68 years. Scintigraphy was performed using the planar whole-body technique (ventral and dorsal projections). Suspect areas were enlarged. Whole-body MRI was conducted using native T1w and STIR sequences in the coronary plane of the whole body, sagittal imaging of spine and breath-hold STIR and T1w-Flash-2D sequences of ribs and chest. Bone scintigraphy and whole-body MRI were evaluated retrospectively by experienced radiologists in a consensus reading on a lesion-based level. Results: whole-body MRI detected significantly more bone metastasis (p = 0.024). 96.4% of the demonstrated skeletal metastases in bone scintigraphy were founded in whole-body MRI while only 58.6% of the depicted metastases in MRI were able to be located in scintigraphy. There was no significant dn scintigraphy. There was no significant difference regarding bone metastasis greater than one centimeter (p = 0.082) in contrast to metastasis less than one centimeter (p = 0.035). Small osteoblastic metastases showed a considerably higher contrast in T1w sequences than in STIR imaging. Further advantages of whole-body MRI were additional information about extra-osseous tumor infiltration and their complications, for example stenosis of spinal canal or vertebral body fractures, found in 42.9% of patients. (orig.)

  16. 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 e 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)

  17. Operational multi-angle hyperspectral remote sensing for feature detection

    Science.gov (United States)

    Bostater, Charles R.; Brooks, Donald K.

    2013-10-01

    Remote sensing results of land and water surfaces from airborne and satellite platforms are dependent upon the illumination geometry and the sensor viewing geometry. Correction of pushbroom hyperspectral imagery can be achieved using bidirectional reflectance factors (BRF's) image features based upon their multi-angle hyperspectral signatures. Ground validation of features and targets utilize non-imaging sensors such as hemispherical goniometers. In this paper, a new linear translation based hyperspectral imaging goniometer system is described. Imagery and hyperspectral signatures obtained from a rotation stage platform and the new linear non-hemispherical goniometer system shows applications and a multi-angle correction approach for multi-angle hyperspectral pushbroom imagery corrections. Results are presented in a manner in order to describe how ground, vessel and airborne based multi-angle hyperspectral signatures can be applied to operational hyperspectral image acquisition by the calculation of hyperspectral anisotropic signature imagery. The results demonstrate the analysis framework from the systems to water and coastal vegetation for exploitation of surface and subsurface feature or target detection based using the multi-angle radiative transfer based BRF's. The hyperspectral pushbroom multi-angle analysis methodology forms a basis for future multi-sensor based multi-angle change detection algorithms.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-09-06

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

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

    OpenAIRE

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

    2013-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-09-15

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

  1. Sensitivity and specificity of interictal EEG-fMRI for detecting the ictal onset zone at different statistical thresholds.

    OpenAIRE

    SimonTousseyn; PatrickDupont; KarolienGoffin; StefanSunaert

    2014-01-01

    There is currently a lack of knowledge about electroencephalography (EEG)-functional magnetic resonance imaging (fMRI) specificity. Our aim was to define sensitivity and specificity of blood oxygen level dependent (BOLD) responses to interictal epileptic spikes during EEG-fMRI for detecting the ictal onset zone (IOZ). We studied 21 refractory focal epilepsy patients who had a well-defined IOZ after a full presurgical evaluation and interictal spikes during EEG-fMRI. Areas of spike-related BOL...

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

    International Nuclear Information System (INIS)

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

  3. Ecphory of Autobiographical Memories: an fMRI Study on Recent and Remote Memory Retrieval

    OpenAIRE

    Steinvorth, Sarah; Corkin, Suzanne; Halgren, Eric

    2005-01-01

    Ecphory occurs when one recollects a past event cued by a trigger, such as a picture, odor, or name. It is a central component of autobiographical memory, which allows us to “travel mentally back in time” and re-experience specific events from our personal past. Using fMRI and focusing on the role of medial temporal lobe (MTL) structures, we investigated the brain bases of autobiographical memory and whether they change with the age of memories. Importantly, we used an ecphory task in whi...

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

    Science.gov (United States)

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

    2015-04-01

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

  5. 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.)

  6. 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. k 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

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    S.M. Messerli

    2002-01-01

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

  9. 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.)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-08-15

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

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

    Science.gov (United States)

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

    2013-03-01

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

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

    Directory of Open Access Journals (Sweden)

    Miu?in-Vukadinovi? Ivana

    2008-01-01

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

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

    Science.gov (United States)

    Krezhova, Dora; Maneva, Svetla; Zdravev, Tomas

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

  14. Magnetically-assisted remote control (MARC) steering of endovascular catheters for interventional MRI: a model for deflection and design implications.

    Science.gov (United States)

    Settecase, Fabio; Sussman, Marshall S; Wilson, Mark W; Hetts, Steven; Arenson, Ronald L; Malba, Vincent; Bernhardt, Anthony F; Kucharczyk, Walter; Roberts, Timothy P L

    2007-08-01

    Current applied to wire coils wound at the tip of an endovascular catheter can be used to remotely steer a catheter under magnetic resonance imaging guidance. In this study, we derive and validate an equation that characterizes the relationship between deflection and a number of physical factors: theta/sin(gamma-theta) = nIABL/EI(A) where theta is the deflection angle, n is the number of solenoidal turns, I is the current, A is the cross-sectional area of the catheter tip, B is the magnetic resonance (MR) scanner main magnetic field, L is the unconstrained catheter length, E is Young's Modulus for the catheter material, and I(A) is the area moment of inertia, and y is the initial angle between the catheter tip and B. Solenoids of 50, 100, or 150 turns were wound on 1.8 F and 5 F catheters. Varying currents were applied remotely using a DC power supply in the MRI control room. The distal catheter tip was suspended within a phantom at varying lengths. Images were obtained with a 1.5 T or a 3 T MR scanner using "real-time" MR pulse sequences. Deflection angles were measured on acquired images. Catheter bending stiffess was determined using a tensile testing apparatus and a stereomicroscope. Predicted relationships between deflection and various physical factors were observed (R2 = 0.98-0.99). The derived equation provides a framework for modeling of the behavior of the specialized catheter tip. Each physical factor studied has implications for catheter design and device implementation. PMID:17879774

  15. MRI of the Breast for the Detection and Assessment of the Size of Ductal Carcinoma in Situ

    International Nuclear Information System (INIS)

    The aim of the study was to compare the accuracy of magnetic resonance imaging (MRI) and mammography for the detection and assessment of the size of ductal carcinoma in situ (DCIS). The preoperative contrast-enhanced MRI and mammography were analyzed in respect of the detection and assessment of the size of DCIS in 72 patients (age range: 30 67 years, mean age: 47 years). The MRI and mammographic measurements were compared with the histopathologic size with using the Pearson's correlation coefficients and the Mann-Whitney u test. We evaluated whether the breast density, the tumor nuclear grade, the presence of comedo necrosis and microinvasion influenced the MRI and mammographic size estimates by using the chi-square test. Of the 72 DCIS lesions, 68 (94%) were detected by MRI and 62 (86%) were detected by mammography. Overall, the Pearson's correlation of the size between MRI and histopathology was 0.786 versus 0.633 between mammography and histopathology (p < 0.001). MRI underestimated the size by more than 1 cm (including false negative examination) in 12 patients (17%), was accurate in 52 patients (72%) and overestimated the size by more than 1 cm in eight patients (11%) whereas mammography underestimated the size in 25 patients (35%), was accurate in 31 patients (43%) and overestimated the size in 16 patients (22%). The MRI, but not the mammography, showed significant correlation for the assessment of the size of tumor in noncomedo DCIS (p < 0.001 vs p = 0.060). Tnoncomedo DCIS (p < 0.001 vs p = 0.060). The assessment of tumor size by MRI was affected by the nuclear grade (p = 0.008) and the presence of comedo necrosis (p = 0.029), but not by the breast density (p 0.747) or microinvasion (p = 0.093). MRI was more accurate for the detection and assessment of the size of DCIS than mammography

  16. A new tool for the rapid remote detection of leaks from subsea pipelines during remotely operated vehicle inspections

    Science.gov (United States)

    McStay, D.; McIlroy, J.; Forte, A.; Lunney, F.; Greenway, T.; Thabeth, K.; Dean, G.

    2005-06-01

    A new 2000 m depth rated subsea sensor that can effectively, rapidly and remotely detect leaks of fluorescein dye, leak detection chemicals and hydraulic fluids from underwater structures is reported. The system utilizes ultra-bright LED technology to project a structured beam of light, at a wavelength suitable to excite the fluorescence of the target material, into the water column. The resultant fluorescence is collected and digital signal processing used to extract the intensity. The system is capable of detecting ppm concentrations of fluorescein at a range of 2.5 m in water in real time. The ability to stand-off from subsea structures, while rapidly detecting the chemicals makes the system highly suited to subsea leak inspections with remotely operated vehicles or autonomous underwater vehicles, as it allows the vehicles to be flown quickly and safely over the structure to be inspected. This increases both the speed and effectiveness of the inspection. The remote detection capability is also highly effective for probing complex underwater structures. The system has been successfully used in real subsea survey applications and has been found to be effective, user friendly and to dramatically reduce inspection times and hence costs.

  17. 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 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.

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

    Science.gov (United States)

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

    2015-01-01

    Background Tissue permeabilization by electroporation (EP) is a promising technique to treat certain cancers. Non-invasive methods for verification of induced permeabilization are important, especially in deep-seated cancers. In this study we evaluated diffusion-weighted magnetic resonance imaging (DW-MRI) as a quantitative method for detecting EP-induced membrane permeabilization of brain tissue using a rat brain model. Material and methods Fifty-four anesthetized Sprague-Dawley male rats were electroporated in the right hemisphere, using different voltage levels to induce no permeabilization (NP), transient membrane permeabilization (TMP), and permanent membrane permeabilization (PMP), respectively. DW-MRI was acquired 5 minutes, 2 hours, 24 hours and 48 hours after EP. Histology was performed for validation of the permeabilization states. Tissue content of water, Na+, K+, Ca2+, and extracellular volume were determined. The Kruskal-Wallis test was used to compare the DW-MRI parameters, apparent diffusion coefficient (ADC) and kurtosis, at different voltage levels. The two-sample Mann- Whitney test with Holm's Bonferroni correction was used to identify pairs of significantly different groups. The study was approved by the Danish Animal Experiments Inspectorate. Results and conclusion Results showed significant difference in the ADC between TMP and PMP at 2 hours (p < 0.001) and 24 hours (p < 0.05) after EP. Kurtosis was significantly increased both at TMP (p < 0.05) and PMP (p < 0.001) 5 minutes after EP, compared to NP. Kurtosis was also significantly higher at 24 hours (p < 0.05) and 48 hours (p < 0.05) at PMP compared to NP. Physiological parameters indicated correlation with the permeabilization states, supporting the DW-MRI findings. We conclude that DW-MRI is capable of detecting EP-induced permeabilization of brain tissue and to some extent of differentiating NP, TMP and PMP using appropriate scan timing. PMID:25591820

  19. Symmetry-based detection and diagnosis of DCIS in breast MRI

    Science.gov (United States)

    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

    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.

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

    DEFF Research Database (Denmark)

    Mahmood, Faisal; Hansen, Rasmus H

    2015-01-01

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

  1. Whole-body MRI for detecting metastatic bone tumor. Diagnostic value of diffusion-weighted images

    International Nuclear Information System (INIS)

    We assessed the diagnostic value of whole body magnetic resonance (MR) imaging (WB-MRI) using diffusion-weighted images (DWI) for detecting bone metastasis and compared it with that of skeletal scintigraphy (SS). Thirty patients with malignancies (breast cancer, 17 patients; prostate cancer, 9; and one patient each, thyroid cancer, liposarcoma, leiomyosarcoma, and extraskeletal Ewing sarcoma) underwent both WB-MRI and SS to detect bone metastasis. All patients were followed more than 6 months by MR imaging, SS, or computed tomographic (CT) examination. For WB-MRI, patients were placed in feet-first supine position with table-top extender and quadrature body coil. We acquired DWI (axial plane from lower neck to proximal femur) (single shot short TI inversion-recovery [STIR]: repetition time [TR] 6243/echo time [TE] 59/inversion time [TI] 180 ms; b value: 600 s/mm2; 5-mm slice thickness; 112 x 112 matrix), T1-weighted fast spin echo (T1WI), and STIR (sagittal plane of total spine images and coronal plane of whole body images) images. Four blinded readers independently and separately interpreted images of combined MR sequences of T1WI+STIR (session 1) and T1WI+STIR+DWI (session 2). In 10 of 30 patients, we detected a total of 52 metastatic bone lesions; in the other 20, follow-up examinations confirmed no metastatic bone lesions. For these 52 lesions, for session 2, the mean sensitivity was 96% and the positive predisensitivity was 96% and the positive predictive value (PPV) was 98%. Those values were superior to those of session 1 (sensitivity: 88%; PPV: 95%) and those of SS (sensitivity: 96%; PPV: 94%). WB-MRI that included DWI was useful for detecting bone metastasis. (author)

  2. Phase-multiplexed detection for accelerated nanoscale MRI

    OpenAIRE

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

    2014-01-01

    We report a method for parallel detection of nanoscale nuclear magnetic resonance signals. Our technique relies on phase multiplexing, where the signals from different nuclear spin ensembles are encoded in the phase of an ultrasensitive magnetic detector. We demonstrate this technique by simultaneously acquiring statistically polarized spin signals from two different nuclear species (1H, 19F) and from up to six spatial locations in a nanowire test sample using a magnetic res...

  3. Synthesis of an In vivo MRI-detectable Apoptosis Probe

    OpenAIRE

    Lam, Justin; Simpson, Paul C.; Yang, Phillip C.; Dash, Rajesh

    2012-01-01

    Cellular apoptosis is a prominent feature of many diseases, and this programmed cell death typically occurs before clinical manifestations of disease are evident. A means to detect apoptosis in its earliest, reversible stages would afford a pre-clinical 'window' during which preventive or therapeutic measures could be taken to protect the heart from permanent damage. We present herein a simple and robust method to conjugate human Annexin V (ANX), which avidly binds to cells in the earliest, r...

  4. Medial temporal lobe activity for recognition of recent and remote famous names: an event-related fMRI study.

    Science.gov (United States)

    Douville, Kelli; Woodard, John L; Seidenberg, Michael; Miller, Sarah K; Leveroni, Catherine L; Nielson, Kristy A; Franczak, Malgorzata; Antuono, Piero; Rao, Stephen M

    2005-01-01

    Previous neuroimaging studies examining recognition of famous faces have identified activation of an extensive bilateral neural network [Gorno Tempini, M. L., Price, C. J., Josephs, O., Vandenberghe, R., Cappa, S. F., Kapur, N. et al. (1998). The neural systems sustaining face and proper-name processing. Brain, 121, 2103-2118], including the medial temporal lobe (MTL) and specifically the hippocampal complex [Haist, F., Bowden, G. J., & Mao, H. (2001). Consolidation of human memory over decades revealed by functional magnetic resonance imaging. Nature Neuroscience, 4, 1139-1145; Leveroni, C. L., Seidenberg, M., Mayer, A. R., Mead, L. A., Binder, J. R., & Rao, S. M. (2000). Neural systems underlying the recognition of familiar and newly learned faces. Journal of Neuroscience, 20, 878-886]. One model of hippocampal functioning in autobiographical, episodic memory retrieval argues that the hippocampal complex remains active in retrieval tasks regardless of time or age of memory (multiple trace theory, MTT), whereas another proposal posits that the hippocampal complex plays a time-limited role in retrieval of autobiographical memories. The current event-related fMRI study focused on the medial temporal lobe and its response to recognition judgments of famous names from two distinct time epochs (1990s and 1950s) in 15 right-handed healthy older adults (mean age=70 years). A pilot study with an independent sample of young and older subjects ensured that the stimuli were representative of a recent and remote time period. Increased MR signal activity was observed on a bilateral basis for both the hippocampus and parahippocampal gyrus (PHG) during recognition of familiar names from both the recent and remote time periods when compared to non-famous names. However, the impulse response functions in the right hippocampus and right PHG demonstrated a differential response to stimuli from different time epochs, with the 1990s names showing the greatest MR signal intensity change, followed by the 1950s names, followed by foils. The finding that recognition of famous names produced significant bilateral MTL activation regardless of time epoch relative to foils provides support for the MTT model. However, the finding of a temporal gradient in the right MTL also provides support for the HC model, given the greater MTL response associated with recently famous names relative to remotely famous names. PMID:15721182

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

    OpenAIRE

    Lingjia Gu; Ruizhi Ren; Shuang Zhang

    2011-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Hai Jin

    2012-02-01

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

  7. Detection of cerebral microvascular lesions using 7 T MRI in patients with neuropsychiatric systemic lupus erythematosus.

    Science.gov (United States)

    Murata, Okinori; Sasaki, Nobuhito; Sasaki, Makoto; Kowada, Koko; Ninomiya, Yukari; Oikawa, Yuka; Kobayashi, Hitoshi; Nakamura, Yutaka; Yamauchi, Kohei

    2015-01-01

    Neuropsychiatric systemic lupus erythematosus (NPSLE) is speculated to be caused by disturbed microcirculation of the central nervous system. However, characteristic imaging findings of NPSLE have not been established. Hence, we investigated whether high-resolution images obtained using ultrahigh field MRI at 7 T can detect microcerebrovascular lesions in patients with NPSLE that have never been detected by conventional MRI. We prospectively examined 20 patients with SLE, including five with NPSLE, using a 7 T MRI scanner. High-resolution two-dimensional T2-weighted images and high-resolution three-dimensional T1-weighted images (T1WIs) before and after the administration of contrast agents were obtained. On the high-resolution T1WIs obtained at 7 T, minute punctate/linear hyperintense lesions in subcortical and/or cortical areas were found in four (80%) NPSLE patients and one (7%) non-NPSLE patient. Further, the minute punctate enhanced lesions in these areas were found on contrast-enhanced T1WIs in only three (60%) NPSLE patients. These findings suggesting microvascular thrombi or inflammation were significantly more frequent in NPSLE than in non-NPSLE patients (P=0.001). In contrast, other imaging findings, laboratory findings, and clinical characteristics were not different between the two groups. High-resolution T1WIs obtained at 7 T can detect minute lesions, indicating intracerebral microvascular lesions in patients with NPSLE. PMID:25426827

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

    DEFF Research Database (Denmark)

    Eskildsen, Simon Fristed; Coupé, Pierrick

    2014-01-01

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

  9. Detection of Rib Metastases in Patients with Lung Cancer: A Comparative Study of MRI, CT and Bone Scintigraphy

    OpenAIRE

    Chen, Yan-Qing; Yang, Yang; Xing, Yan-Fen; Jiang, Sen; Sun, Xi-Wen

    2012-01-01

    We retrospectively investigated the imaging findings of bone scintigraphy, chest CT and chest MRI in 55 cases of lung cancer. The sensitivity, specificity and accuracy of the detection of rib metastases were compared between imaging modalities on both a per-lesion and a per-patient basis. On a per-lesion basis, MRI sensitivity and accuracy were significantly higher than that of bone scintigraphy and CT (P0.05). MRI appears to be superior for the detection of ribs metastases in lung cancer.

  10. Automatic left ventricle detection in MRI images using marginal space learning and component-based voting

    Science.gov (United States)

    Zheng, Yefeng; Lu, Xiaoguang; Georgescu, Bogdan; Littmann, Arne; Mueller, Edgar; Comaniciu, Dorin

    2009-02-01

    Magnetic resonance imaging (MRI) is currently the gold standard for left ventricle (LV) quantification. Detection of the LV in an MRI image is a prerequisite for functional measurement. However, due to the large variations in orientation, size, shape, and image intensity of the LV, automatic detection of the LV is still a challenging problem. In this paper, we propose to use marginal space learning (MSL) to exploit the recent advances in learning discriminative classifiers. Instead of learning a monolithic classifier directly in the five dimensional object pose space (two dimensions for position, one for orientation, and two for anisotropic scaling) as full space learning (FSL) does, we train three detectors, namely, the position detector, the position-orientation detector, and the position-orientation-scale detector. Comparative experiments show that MSL significantly outperforms FSL in both speed and accuracy. Additionally, we also detect several LV landmarks, such as the LV apex and two annulus points. If we combine the detected candidates from both the whole-object detector and landmark detectors, we can further improve the system robustness. A novel voting based strategy is devised to combine the detected candidates by all detectors. Experiments show component-based voting can reduce the detection outliers.

  11. A data-driven approach to prostate cancer detection from dynamic contrast enhanced MRI.

    Science.gov (United States)

    Haq, Nandinee Fariah; Kozlowski, Piotr; Jones, Edward C; Chang, Silvia D; Goldenberg, S Larry; Moradi, Mehdi

    2015-04-01

    Magnetic resonance imaging (MRI), particularly dynamic contrast enhanced (DCE) imaging, has shown great potential in prostate cancer diagnosis and staging. In the current practice of DCE-MRI, diagnosis is based on quantitative parameters extracted from the series of T1-weighted images acquired after the injection of a contrast agent. To calculate these parameters, a pharmacokinetic model is fitted to the T1-weighted intensities. Most models make simplistic assumptions about the perfusion process. Moreover, these models require accurate estimation of the arterial input function, which is challenging. In this work we propose a data-driven approach to characterization of the prostate tissue that uses the time series of DCE T1-weighted images without pharmacokinetic modeling. This approach uses a number of model-free empirical parameters and also the principal component analysis (PCA) of the normalized T1-weighted intensities, as features for cancer detection from DCE MRI. The optimal set of principal components is extracted with sparse regularized regression through least absolute shrinkage and selection operator (LASSO). A support vector machine classifier was used with leave-one-patient-out cross validation to determine the ability of this set of features in cancer detection. Our data is obtained from patients prior to radical prostatectomy and the results are validated based on histological evaluation of the extracted specimens. Our results, obtained on 449 tissue regions from 16 patients, show that the proposed data-driven features outperform the traditional pharmacokinetic parameters with an area under ROC of 0.86 for LASSO-isolated PCA parameters, compared to 0.78 for pharmacokinetic parameters. This shows that our novel approach to the analysis of DCE data has the potential to improve the multiparametric MRI protocol for prostate cancer detection. PMID:25060941

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-01-01

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

  13. A pooled analysis of MRI in the detection of bone marrow infiltration in patients with malignant lymphoma

    International Nuclear Information System (INIS)

    Aim: To explore the role of magnetic resonance imaging (MRI) in detecting bone marrow infiltration of malignant lymphoma through a systematic review and meta-analysis. Materials and methods: Studies that evaluated the diagnostic performance of MRI in detecting bone marrow infiltration of malignant lymphoma were acquired from the MEDLINE, EMBASE, Cancerlit, and Cochrane Library database, from February 1987 to May 2012. Pooled estimation and subgroup analysis data were obtained by statistical analysis. Results: A total of 13 studies involving 634 patients who fulfilled all of the inclusion criteria were considered for the analysis. No publication bias was found (p = 0.70). The pooled sensitivity of MRI was 0.82 [95% confidence intervals (CI): 0.70–0.90] and the pooled specificity was 0.79 (95% CI: 0.72–0.84). Overall, positive likelihood ratios (LR+) was 3.9 (95% CI: 2.8–5.4) and negative likelihood ratios (LR?) was 0.23 (95% CI: 0.13–0.41). In patients with high pre-test probabilities, MRI enabled confirmation of bone marrow involvement; in patients with low pre-test probabilities, MRI enabled exclusion of bone marrow involvement. Worst-case-scenario (pre-test probability, 50%) post-test probabilities were 80% and 18% for positive and negative MRI results, respectively. In subgroup analysis, MRI performed with 1.5 T devices had higher pooled specificity (0.80, 95% CI: 0.71–0.88) than the MRI with ?1 T (0.78, 95% CI: 0.71–0.85; p < 0.05). The pooled sensitivity of MRI with diffusion-weighted imaging (DWI) was 0.65 (95% CI: 0.39–0.92) and the pooled specificity was 0.83 (95% CI: 0.69–0.97). The sensitivity and specificity of MRI without DWI was 0.85 (95% CI: 0.76–0.94) and 0.79 (95% CI: 0.72–0.85), respectively. Conclusion: A limited number of small studies indicate that MRI can serve as a valuable tool for detecting bone marrow infiltration of malignant lymphoma. Results were most promising when performing MRI using high field strength devices. MRI with DWI is shown to be more specific than conventional MRI techniques. This deserves further investigation in future studies

  14. Mapping litter decomposition by remote-detected indicators

    Directory of Open Access Journals (Sweden)

    L. Rossi

    2006-06-01

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

  15. 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 theibecause 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)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-11-15

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

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

    International Nuclear Information System (INIS)

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

  18. Pulse artifact detection in simultaneous EEG-fMRI recording based on EEG map topography.

    Science.gov (United States)

    Iannotti, Giannina R; Pittau, Francesca; Michel, Christoph M; Vulliemoz, Serge; Grouiller, Frédéric

    2015-01-01

    One of the major artifact corrupting electroencephalogram (EEG) acquired during functional magnetic resonance imaging (fMRI) is the pulse artifact (PA). It is mainly due to the motion of the head and attached electrodes and wires in the magnetic field occurring after each heartbeat. In this study we propose a novel method to improve PA detection by considering the strong gradient and inversed polarity between left and right EEG electrodes. We acquired high-density EEG-fMRI (256 electrodes) with simultaneous electrocardiogram (ECG) at 3 T. PA was estimated as the voltage difference between right and left signals from the electrodes showing the strongest artifact (facial and temporal). Peaks were detected on this estimated signal and compared to the peaks in the ECG recording. We analyzed data from eleven healthy subjects, two epileptic patients and four healthy subjects with an insulating layer between electrodes and scalp. The accuracy of the two methods was assessed with three criteria: (i) standard deviation, (ii) kurtosis and (iii) confinement into the physiological range of the inter-peak intervals. We also checked whether the new method has an influence on the identification of epileptic spikes. Results show that estimated PA improved artifact detection in 15/17 cases, when compared to the ECG method. Moreover, epileptic spike identification was not altered by the correction. The proposed method improves the detection of pulse-related artifacts, particularly crucial when the ECG is of poor quality or cannot be recorded. It will contribute to enhance the quality of the EEG increasing the reliability of EEG-informed fMRI analysis. PMID:25307731

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

    Science.gov (United States)

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

    2015-04-01

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

  20. Breast MRI in detecting primary malignancy of patients presenting with axillary metastases and negative X-ray mammography

    International Nuclear Information System (INIS)

    Objective: To evaluate the role of breast MRI in detecting the primary malignancy in patients presenting solely with axillary lymph node metastases. Methods: Thirty-three patients with axillary lymph node metastases but negative findings on either physical examination or mammography underwent breast MRI to identify occult breast carcinoma. MRI of the breast was assessed according to BI-RADS criteria. The pathologic diagnosis was made according to the standard criteria by the WHO Classification of' Tumor. Results: Among 33 patients presenting solely with axillary metastases, 30 patients underwent modified radical mastectomy. Primary breast carcinoma was proven in 17 patients. MRI detected lesions in 16 patients, including 10 masses and 6 non-mass lesions. Size of the masses ranged from 0.5 to 2.6 cm (mean 1.5 cm). Six lesions were smaller than 1.5 cm in size. Non-mass lesions showed ductal enhancement in 4 cases and segmental enhancement in 2 cases. One patient with tumor detected by histopathology showed no abnormal enhancement on MRI. No tumor was found at mastectomy in the other 13 women, and negative MR findings were revealed in 9. Four cases with suspicious enhancement on MRI had no corresponding primary foci on pathology. Three patients didn't undergo surgical procedure, The sensitivity, specificity, and accuracy of MRI in the diagnosis of the primary malignancy were 94.1%, 69.2%, and 83.3%, respectively. Conclusions: Small size of mass and ductal or segmental enhancement of non-mass lesion were common MR features of occult malignancy. MRI showed high sensitivity and accuracy in diagnosing occult breast carcinoma. Breast MRI should be taken in search of occult malignancy in patients with axillary metastases. (authors)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-01-15

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

  2. 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.)

  3. The Value of Prostate MRI with Endorectal Coil in Detecting Seminal Vesicle Involvement in Patients with Prostate Cancer

    Science.gov (United States)

    Ghafoori, Mahyar; Alavi, Manijeh; Shakiba, Madjid; Hoseini, Kamal

    2015-01-01

    Background: In prostate cancer, detection of seminal vesicle involvement is important because it influences the treatment planning and prognosis of the patients. Objectives: The objective of this study was to determine the value of prostate MRI with endorectal coil in the detection of seminal vesicle involvement in patients with prostate cancer. Patients and Methods: A total number of 238 biopsy-proven prostate cancer patients were examined by 1.5 Tesla MRI with a combination of pelvic and endorectal coils to detect seminal vesicle involvement. After radical prostatectomy, the MRI results were compared with pathology results. Results: Seminal vesicle involvement was detected in 67 (28.1%) patients. Pathology confirmed the involvement of seminal vesicles by prostate cancer in 63 patients. In two patients, seminal vesicle involvement was diagnosed by pathology but not detected by MRI. The sensitivity was 0.97 [95% confidence interval = 0.89-0.99], the specificity was 0.98 [95% confidence interval = 0.94-0.99], the positive predictive value was 0.94 [95% confidence interval = 0.85-0.98], and the negative predictive value was 0.99 [95% confidence interval = 0.96-0.99]. Conclusions: MRI with endorectal coil is a valuable imaging technique with suitable accuracy in detecting seminal vesicle involvement in prostate cancer. PMID:25793086

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

    OpenAIRE

    Zarco-Tejada, Pablo J.; Berjón, A.; Miller, J. R.

    2004-01-01

    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, ...

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

    Science.gov (United States)

    Tiwari, Pallavi; Kurhanewicz, John; Madabhushi, Anant

    2013-02-01

    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

  6. Detecting the presence of disease by unifying two methods of remote sensing

    Science.gov (United States)

    Reames, Steve

    There is currently no effective tool available to quickly and economically measure a change in landmass in the setting of biomedical professionals and environmental specialists. The purpose of this study is to structure and demonstrate a statistical change-detection method using remotely sensed data that can detect the presence of an infectious land borne disease. Data sources included the Texas Department of Health database, which provided the types of infectious land borne diseases and indicated the geographical area to study. Methods of data collection included the gathering of images produced by digital orthophoto quadrangle and aerial videography and Landsat. Also, a method was developed to identify statistically the severity of changes of the landmass over a three-year period. Data analysis included using a unique statistical detection procedure to measure the severity of change in landmass when a disease was not present and when the disease was present. The statistical detection method was applied to two different remotely sensed platform types and again to two like remotely sensed platform types. The results indicated that when the statistical change detection method was used for two different types of remote sensing mediums (i.e., digital orthophoto quadrangle and aerial videography), the results were negative due to skewed and unreliable data. However, when two like remote sensing mediums were used (i.e., videography to videography and Landsat to Landsat) the results were positive and the data were reliable.

  7. Detecting remotely related proteins by their interactions and sequence similarity

    OpenAIRE

    Espadaler, Jordi; Aragüés, Ramón; Eswar, Narayanan; Marti-Renom, Marc A.; Querol, Enrique; Avilés, Francesc X; Sali, Andrej; Oliva, Baldomero

    2005-01-01

    The function of an uncharacterized protein is usually inferred either from its homology to, or its interactions with, characterized proteins. Here, we use both sequence similarity and protein interactions to identify relationships between remotely related protein sequences. We rely on the fact that homologous sequences share similar interactions, and, therefore, the set of interacting partners of the partners of a given protein is enriched by its homologs. The approach was benchmarked by assi...

  8. Crop stress detection and classification using hyperspectral remote sensing

    Science.gov (United States)

    Irby, Jon Trenton

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

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-05-01

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

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

    International Nuclear Information System (INIS)

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

  12. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-11-15

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

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

    International Nuclear Information System (INIS)

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

  15. AN APPROACH TO IMPROVING EDGE DETECTION FOR FACIAL AND REMOTELY SENSED IMAGES USING VECTOR ORDER STATISTICS

    Directory of Open Access Journals (Sweden)

    B O. Sadiq

    2015-02-01

    Full Text Available This paper presents an improved edge detection algorithm for facial and remotely sensed images using vector order statistics. The developed algorithm processes coloured images directly without been converted to grey scale. A number of the existing algorithms converts the coloured images into grey scale before detection of edges. But this process leads to inaccurate precision of recognized edges, thus producing false and broken edges in the output edge map. Facial and remotely sensed images consist of curved edge lines which have to be detected continuously to prevent broken edges. In order to deal with this, a collection of pixel approach is introduced with a view to minimizing the false and broken edges that exists in the generated output edge map of facial and remotely sensed images.

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

    OpenAIRE

    Huang, Fengchen; Xu, Lizhong; LI, MIN; Tang, Min

    2012-01-01

    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...

  17. Shadow-based Building Detection and Segmentation in High-resolution Remote Sensing Image

    OpenAIRE

    Dongyue Chen; Shibo Shang; Chengdong Wu

    2014-01-01

    This paper proposes an effective method to extract buildings in high-resolution remote sensing images based on shadow detection. Firstly, a superpixel segmentation algorithm called SLIC is introduced to split the input image into homogeneous patches. LDA-based color features of the patches are extracted for detecting shadow regions. According to the positions of the shadows, an adaptive strategy for seed location and regional growth is developed to accomplish the coarse detection of buildings...

  18. Remote detection of single emitters via optical waveguides

    Science.gov (United States)

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

    2014-05-01

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

  19. Single (19)F probe for simultaneous detection of multiple metal ions using miCEST MRI.

    Science.gov (United States)

    Bar-Shir, Amnon; Yadav, Nirbhay N; Gilad, Assaf A; van Zijl, Peter C M; McMahon, Michael T; Bulte, Jeff W M

    2015-01-14

    The local presence and concentration of metal ions in biological systems has been extensively studied ex vivo using fluorescent dyes. However, the detection of multiple metal ions in vivo remains a major challenge. We present a magnetic resonance imaging (MRI)-based method for noninvasive detection of specific ions that may be coexisting, using the tetrafluorinated derivative of the BAPTA (TF-BAPTA) chelate as a (19)F chelate analogue of existing optical dyes. Taking advantage of the difference in the ion-specific (19)F nuclear magnetic resonance (NMR) chemical shift offset (??) values between the ion-bound and free TF-BAPTA, we exploited the dynamic exchange between ion-bound and free TF-BAPTA to obtain MRI contrast with multi-ion chemical exchange saturation transfer (miCEST). We demonstrate that TF-BAPTA as a prototype single (19)F probe can be used to separately visualize mixed Zn(2+) and Fe(2+) ions in a specific and simultaneous fashion, without interference from potential competitive ions. PMID:25523816

  20. Whole body MRI: improved lesion detection and characterization with diffusion weighted techniques.

    Science.gov (United States)

    Attariwala, Rajpaul; Picker, Wayne

    2013-08-01

    Diffusion-weighted imaging (DWI) is an established functional imaging technique that interrogates the delicate balance of water movement at the cellular level. Technological advances enable this technique to be applied to whole-body MRI. Theory, b-value selection, common artifacts and target to background for optimized viewing will be reviewed for applications in the neck, chest, abdomen, and pelvis. Whole-body imaging with DWI allows novel applications of MRI to aid in evaluation of conditions such as multiple myeloma, lymphoma, and skeletal metastases, while the quantitative nature of this technique permits evaluation of response to therapy. Persisting signal at high b-values from restricted hypercellular tissue and viscous fluid also permits applications of DWI beyond oncologic imaging. DWI, when used in conjunction with routine imaging, can assist in detecting hemorrhagic degradation products, infection/abscess, and inflammation in colitis, while aiding with discrimination of free fluid and empyema, while limiting the need for intravenous contrast. DWI in conjunction with routine anatomic images provides a platform to improve lesion detection and characterization with findings rivaling other combined anatomic and functional imaging techniques, with the added benefit of no ionizing radiation. PMID:23960006

  1. Agricultural practices in grasslands detected by spatial remote sensing.

    Science.gov (United States)

    Dusseux, Pauline; Vertès, Françoise; Corpetti, Thomas; Corgne, Samuel; Hubert-Moy, Laurence

    2014-12-01

    The major decrease in grassland surfaces associated with changes in their management that has been observed in many regions of the earth during the last half century has major impacts on environmental and socio-economic systems. This study focuses on the identification of grassland management practices in an intensive agricultural watershed located in Brittany, France, by analyzing the intra-annual dynamics of the surface condition of vegetation using remotely sensed and field data. We studied the relationship between one vegetation index (NDVI) and two biophysical variables (LAI and fCOVER) derived from a series of three SPOT images on one hand and measurements collected during field campaigns achieved on 120 grasslands on the other. The results show that the LAI appears as the best predictor for monitoring grassland mowing and grazing. Indeed, because of its ability to characterize vegetation status, LAI estimated from remote sensing data is a relevant variable to identify these practices. LAI values derived from the SPOT images were then classified based on the K-Nearest Neighbor (KNN) supervised algorithm. The results points out that the distribution of grassland management practices such as grazing and mowing can be mapped very accurately (Kappa index?=?0.82) at a field scale over large agricultural areas using a series of satellite images. PMID:25182683

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-02-15

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-11-15

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

  4. 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 visualizatioracterization 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.)

  5. Automatic computer aided detection of abnormalities in multi-parametric prostate MRI

    Science.gov (United States)

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

    2011-03-01

    Development of CAD systems for detection of prostate cancer has been a recent topic of research. A multi-stage computer aided detection scheme is proposed to help reduce perception and oversight errors in multi-parametric prostate cancer screening MRI. In addition, important features for development of computer aided detection systems for prostate cancer screening MRI are identified. A fast, robust prostate segmentation routine is used to segment the prostate, based on coupled appearance and anatomy models. Subsequently a voxel classification is performed using a support vector machine to compute an abnormality likelihood map of the prostate. This classification step is based on quantitative voxel features like the apparent diffusion coefficient (ADC) and pharmacokinetic parameters. Local maxima in the likelihood map are found using a local maxima detector, after which regions around the local maxima are segmented. Region features are computed to represent statistical properties of the voxel features within the regions. Region classification is performed using these features, which results in a likelihood of abnormality per region. Performance was validated using a 188 patient dataset in a leave-one-patient-out manner. Ground truth was annotated by two expert radiologists. The results were evaluated using FROC analysis. The FROC curves show that inclusion of ADC and pharmacokinetic parameter features increases the performance of an automatic detection system. In addition it shows the potential of such an automated system in aiding radiologists diagnosing prostate MR, obtaining a sensitivity of respectively 74.7% and 83.4% at 7 and 9 false positives per patient.

  6. Mobile Passive Optical Imager for Remote Gas Detection Project

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

  7. UAS-based thermal remote sensing for crop water stress detection

    Science.gov (United States)

    The remote detection of water stress in a biofuel crop field was investigated using canopy temperature measurements. An experimental trial was set up in the central valley of Maui, Hawaii, comprising different sugarcane varieties and irrigation regimes. An unmanned aerial system (UAS) was equipped w...

  8. Feature analysis for detecting people from remotely sensed images

    Science.gov (United States)

    Sirmacek, Beril; Reinartz, Peter

    2013-01-01

    We propose a novel approach using airborne image sequences for detecting dense crowds and individuals. Although airborne images of this resolution range are not enough to see each person in detail, we can still notice a change of color and intensity components of the acquired image in the location where a person exists. Therefore, we propose a local feature detection-based probabilistic framework to detect people automatically. Extracted local features behave as observations of the probability density function (PDF) of the people locations to be estimated. Using an adaptive kernel density estimation method, we estimate the corresponding PDF. First, we use estimated PDF to detect boundaries of dense crowds. After that, using background information of dense crowds and previously extracted local features, we detect other people in noncrowd regions automatically for each image in the sequence. To test our crowd and people detection algorithm, we use airborne images taken over Munich during the Oktoberfest event, two different open-air concerts, and an outdoor festival. In addition, we apply tests on GeoEye-1 satellite images. Our experimental results indicate possible use of the algorithm in real-life mass events.

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

    Directory of Open Access Journals (Sweden)

    Phinikaridou Alkystis

    2012-06-01

    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.

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

    International Nuclear Information System (INIS)

    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.)

  11. Progress in the Development of Practical Remote Detection of Icing Conditions

    Science.gov (United States)

    Reehorst, Andrew; Politovich, Marcia K.; Zednik, Stephan; Isaac, George A.; Cober, Stewart

    2006-01-01

    The NASA Icing Remote Sensing System (NIRSS) has been under definition and development at NASA Glenn Research Center since 1997. The goal of this development activity is to produce and demonstrate the required sensing and data processing technologies required to accurately remotely detect and measure icing conditions aloft. As part of that effort NASA has teamed with NCAR to develop software to fuse data from multiple instruments into a single detected icing condition product. The multiple instrument approach utilizes a X-band vertical staring radar, a multifrequency microwave, and a lidar ceilometer. The radar data determine cloud boundaries, the radiometer determines the sub-freezing temperature heights and total liquid water content, and the ceilometer refines the lower cloud boundary. Data is post-processed with a LabVIEW program with a resultant supercooled liquid water profile and aircraft hazard depiction. Ground-based, remotely-sensed measurements and in-situ measurements from research aircraft were gathered during the international 2003-2004 Alliance Icing Research Study (AIRS II). Comparisons between the remote sensing system s fused icing product and the aircraft measurements are reviewed here. While there are areas where improvement can be made, the cases examined suggest that the fused sensor remote sensing technique appears to be a valid approach.

  12. 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

  13. Detection of rheumatoid arthritis bone erosions by 2 different dedicated extremity MRI units and conventional radiography.

    DEFF Research Database (Denmark)

    Duer, Anne; Vestergaard, Aage

    2008-01-01

    OBJECTIVES: To compare the ability of 2 different dedicated extremity magnetic resonance imaging (E-MRI) units and conventional radiography (CR) for identifying bone erosions in rheumatoid arthritis (RA) metacarpophalangeal (MCP) and wrist joints. METHODS: CR and 2 MRI-examinations (on 0.2T Esaote Artoscan and 0.2T portable MagneVu MV1000 units) of 418 bones in the dominant wrist and 2.-5. MCP-joints of 15 RA patients and 4 healthy controls were performed and blindedly evaluated for bones being visible and for erosions. RESULTS: In MCP-joints, MagneVu visualized 18.5% of bones entirely and 71.1% were 67-99% visualized. In wrists, MagneVu visualized 1.5% of bones entirely, 39.8% were 67-99% visualized and 19% were not visualized at all. Artoscan and CR visualized all bones entirely. Artoscan/MagneVu/CR found 22/19/15 bones with erosions in MCP-joints and 66/40/13 in wrist joints. 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). MagneVu was particularly more sensitive than CR in metacarpal heads and carpal bones. MagneVu and CR detected 100% and 89%, respectively, of large erosions (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, particularly due to a higher sensitivity in metacarpal heads and carpal bones. The MagneVu detected fewer erosions than the Artoscan, due to a lower average image quality and a smaller proportion of bones being visualized. Udgivelsesdato: 2007-Nov-16

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

    OpenAIRE

    Hai Jin; Yingchun Shen

    2012-01-01

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

  15. Brain mapping and detection of functional patterns in fMRI using wavelet transform; application in detection of dyslexia

    OpenAIRE

    Najarian Kayvan; Ward Kevin; Ji Soo-Yeon

    2009-01-01

    Abstract Background Functional Magnetic Resonance Imaging (fMRI) has been proven to be useful for studying brain functions. However, due to the existence of noise and distortion, mapping between the fMRI signal and the actual neural activity is difficult. Because of the difficulty, differential pattern analysis of fMRI brain images for healthy and diseased cases is regarded as an important research topic. From fMRI scans, increased blood ows can be identified as activated brain regions. Also,...

  16. Regularisation in multi- and hyperspectral remote sensing change detection

    DEFF Research Database (Denmark)

    Nielsen, Allan Aasbjerg

    2005-01-01

    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.

  17. Remote sensing network to detect and identify organic vapours

    Science.gov (United States)

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

    2009-10-01

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

  18. 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-07-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-11-15

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

  1. DETECTION OF ILLEGAL CANNABIS CULTIVATION USING REMOTE SENSING

    Science.gov (United States)

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

  2. USING REMOTE SENSING TO DETECT AND MAP INVASIVE PLANT SPECIES

    Science.gov (United States)

    Invasive exotic plant species present a serious problem to natural resource managers in the United States. This paper presents an overview on the application of aerial photography and airborne videography for detecting invasive plant species in terrestrial and aquatic environments in the United Sta...

  3. Fast motion detection in coded video streams for a large-scale remote video sensor system

    Science.gov (United States)

    Kim, Yong-Sung; Park, Gyu-Hee; Kim, Seung-Hwan; Cho, Hyung-Joon

    2014-10-01

    A large number of remote video sensors are being deployed in the world to collect, store, and analyze the real-world data. Since a remote video sensor produces very large data, the total amount of video data are extremely large in size, complexity, and capacity. Important events from a remote video sensor are closely related to a motion in video. We present, in this paper, a fast motion detection method based on the number of bits used for encoding a video stream and the GOP-level motion detection. A low complexity measurement of the number of bits is performed in the coded video sequence and then, we store and process the coded video stream only if the total bits are larger than a pre-defined threshold. We also use a GOP level motion detection to reduce processing overhead compared to the conventional motion vector-based approach which processes every frame. Manipulating the number of bits is itself a much easier task than full reconstruction of each pixel of a video frame and it can save storage cost because it only stores a coded video sequence with a motion. The proposed method also contributes to reduction of computational complexity compared to the manipulation of motion vectors per 4x4 macro block. To evaluate our method, we deployed a centralized single server connected to H.264 capable remote video sensors. Results on the video sequences showed that the proposed approach can process more video sequences than the conventional compressed domain approach.

  4. Detecting Weed Infestations in Soybean Using Remote Sensing.

    Science.gov (United States)

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

    2007-12-01

    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 weed-free weed-infested areas. Increased reflectance from weed-infested areas was most likely due to increased biomass and canopy cover. Residue masked differences between weed-free and weed- infested areas during the 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.

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

    Science.gov (United States)

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

    2014-12-01

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

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

    Directory of Open Access Journals (Sweden)

    S.M.M. Kahaki

    2012-09-01

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

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

    Science.gov (United States)

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

    2015-06-01

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

  8. 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)

    D. Janaki Sathya

    2011-09-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Baumann, Tobias [Department of Diagnostic Radiology, University Hospital Freiburg, Hugstetter Strasse 49, 79095 Freiburg (Germany)], E-mail: tobias.baumann@uniklinik-freiburg.de; Ludwig, Ute [Department of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Hugstetter Strasse 49, 79095 Freiburg (Germany); Pache, Gregor [Department of Diagnostic Radiology, University Hospital Freiburg, Hugstetter Strasse 49, 79095 Freiburg (Germany); Fautz, Hans-Peter [Department of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Hugstetter Strasse 49, 79095 Freiburg (Germany); Kotter, Elmar; Langer, Mathias; Schaefer, Oliver [Department of Diagnostic Radiology, University Hospital Freiburg, Hugstetter Strasse 49, 79095 Freiburg (Germany)

    2010-03-15

    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.

  10. 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, respectiv2% 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Jerry Myers

    2005-04-15

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

  12. Remote Mine Detection Technologies for Land and Water Environments

    Energy Technology Data Exchange (ETDEWEB)

    Hoover, Eddie R.

    1999-05-11

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

  13. High-resolution remotely sensed small target detection by imitating fly visual perception mechanism.

    Science.gov (United States)

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

    2012-01-01

    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 high-resolution remote sensing data. After the comparison of prevailing simulation mechanism behind fly visual systems, we propose a fly-imitated visual system method of information processing for high-resolution remote sensing data. A small target detector and corresponding detection algorithm are designed by simulating the mechanism of information acquisition, compression, and fusion of fly visual system and the function of pool cell and the character of nonlinear self-adaption. Experiments verify the feasibility and rationality of the proposed small target detection model and fly-imitated visual perception method. PMID:22291854

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

    Directory of Open Access Journals (Sweden)

    D. R. Thompson

    2015-06-01

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

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

    Directory of Open Access Journals (Sweden)

    M. Anitha

    2012-04-01

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

  16. Optical detection system for multispectral UV fluorescence laser remote sensing measurements

    Energy Technology Data Exchange (ETDEWEB)

    Tisone, G.C.; Clark, B.; Wakefield-Reyes, C.; Hargis, P.H. Jr.; Michie, B.; Downey, T.L.; Mills, R.A.

    1994-05-25

    A mobile laser remote sensing system is being developed for multispectral UV fluorescence detection of vapor, liquid, and solid effluents. TM system uses laser wavelengths between 250 and 400 nm to excite UV fluorescence spectra that can be used to detect and identify species in multicomponent chemical mixtures. With a scanning mirror assembly, the system is designed to map chemical concentrations with a range resolution of {approximately}5 m. In this paper we describe the optical detection system (scanning mirror assembly, 76 cm diameter collection telescope, relay optics, spectrometers, and detectors) associated data acquisition and control electronics. We also describe unique diagnostic software that is used for instrument setup and control.

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

    International Nuclear Information System (INIS)

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

  18. Non-contact biopotential sensor for remote human detection

    International Nuclear Information System (INIS)

    This paper describes a new low-cost, low-noise displacement current sensor developed for non-contact measurements of human biopotentials and well suited for detection of human presence applications. The sensor employs a simple, improvised transimpedance amplifier that eliminates the need for ultra high values resistors normally needed in current amplifiers required for this type of measurements. The sensor provides an operational bandwidth of 0.5 - 250 Hz, and a noise level of 7.8?V?Hz at 1 Hz down to 30nV/?Hz at 1 kHz. Reported experimental results demonstrate the sensor's capability in measuring heart related biopotentials within 0.5m off-body distance, and muscle related biopotentials within 10m no obstacles off-body distance, and 5m off-body distance with a concrete wall in between.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-05-15

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

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

    International Nuclear Information System (INIS)

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

  1. 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.)

  2. Detecting Patterns of a Technological Intelligence in Remotely Sensed Imagery

    Science.gov (United States)

    Carlotto, M. J.

    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.

  3. 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)

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    "A. Mirzajani

    2005-08-01

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

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

    Directory of Open Access Journals (Sweden)

    Rischke Hans Christian

    2012-10-01

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

  7. 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

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

    International Nuclear Information System (INIS)

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

  9. 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.)

  10. 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.

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

    DEFF Research Database (Denmark)

    Hougaard, K D; Hjort, N

    2013-01-01

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

  12. 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.)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-01-15

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

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

    Directory of Open Access Journals (Sweden)

    Wang Luo

    2012-08-01

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

  15. Detection of ancient Egyptian archaeological sites using satellite remote sensing and digital image processing

    Science.gov (United States)

    Corrie, Robert K.

    2011-11-01

    Satellite remote sensing is playing an increasingly important role in the detection and documentation of archaeological sites. Surveying an area from the ground using traditional methods often presents challenges due to the time and costs involved. In contrast, the multispectral synoptic approach afforded by the satellite sensor makes it possible to cover much larger areas in greater spectral detail and more cost effectively. This is especially the case for larger scale regional surveys, which are helping to contribute to a better understanding of ancient Egyptian settlement patterns. This study presents an overview of satellite remote sensing data products, methodologies, and image processing techniques for detecting lost or undiscovered archaeological sites with reference to Egypt and the Near East. Key regions of the electromagnetic spectrum useful for site detection are discussed, including the visible near-infrared (VNIR), shortwave infrared (SWIR), thermal infrared (TIR), and microwave (radar). The potential of using Google Earth as both a data provider and a visualization tool is also examined. Finally, a case study is presented for detecting tell sites in Egypt using Landsat ETM+, ASTER, and Google Earth imagery. The results indicated that principal components analysis (PCA) was successfully able to detect and differentiate tell sites from modern settlements in Egypt's northwestern Nile Delta region.

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

    Directory of Open Access Journals (Sweden)

    Mustafa Bolca

    2005-01-01

    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.

  17. Sensitivity and Specificity of Interictal EEG-fMRI for Detecting the Ictal Onset Zone at Different Statistical Thresholds.

    Science.gov (United States)

    Tousseyn, Simon; Dupont, Patrick; Goffin, Karolien; Sunaert, Stefan; Van Paesschen, Wim

    2014-01-01

    There is currently a lack of knowledge about electroencephalography (EEG)-functional magnetic resonance imaging (fMRI) specificity. Our aim was to define sensitivity and specificity of blood oxygen level dependent (BOLD) responses to interictal epileptic spikes during EEG-fMRI for detecting the ictal onset zone (IOZ). We studied 21 refractory focal epilepsy patients who had a well-defined IOZ after a full presurgical evaluation and interictal spikes during EEG-fMRI. Areas of spike-related BOLD changes overlapping the IOZ in patients were considered as true positives; if no overlap was found, they were treated as false-negatives. Matched healthy case-controls had undergone similar EEG-fMRI in order to determine true-negative and false-positive fractions. The spike-related regressor of the patient was used in the design matrix of the healthy case-control. Suprathreshold BOLD changes in the brain of controls were considered as false positives, absence of these changes as true negatives. Sensitivity and specificity were calculated for different statistical thresholds at the voxel level combined with different cluster size thresholds and represented in receiver operating characteristic (ROC)-curves. Additionally, we calculated the ROC-curves based on the cluster containing the maximal significant activation. We achieved a combination of 100% specificity and 62% sensitivity, using a Z-threshold in the interval 3.4-3.5 and cluster size threshold of 350 voxels. We could obtain higher sensitivity at the expense of specificity. Similar performance was found when using the cluster containing the maximal significant activation. Our data provide a guideline for different EEG-fMRI settings with their respective sensitivity and specificity for detecting the IOZ. The unique cluster containing the maximal significant BOLD activation was a sensitive and specific marker of the IOZ. PMID:25101049

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

    Directory of Open Access Journals (Sweden)

    Melissa M. Littlefield

    2014-03-01

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

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

    OpenAIRE

    Aglietta, Massimo

    2006-01-01

    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 (...

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

    International Nuclear Information System (INIS)

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

  1. 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

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

    Science.gov (United States)

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

    2005-09-01

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

  3. 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.)

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

    CERN Document Server

    Babykalpana, Y

    2010-01-01

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

  5. Memory detection using fMRI - Does the encoding context matter?

    Science.gov (United States)

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

    2015-06-01

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  8. Fiber optic TDLAS-based multi-gas remote detection system for mine goaf fire

    Science.gov (United States)

    Wei, Yubin; Li, Yanfang; Shang, Ying; Zhang, Tingting; Song, Zhiqiang; Wang, Chang; Liu, Tongyu

    2010-10-01

    Spontaneous combustion in coal goaf area is one of major disasters in coal mines. Detection technology based on signature Gas is the primary means of spontaneous combustion forecasting of coal goaf area. A real-time remote fire gas detection system is proposed based on tunable diode laser absorption spectroscopy technology, to achieve valid test of signature gas (CO, CO2, CH4, C2H2 and C2H4). The System uses the wavelength, respectively 1.567um, 1.608um, 1.653um, 1.530um, 1.623um near-infrared band fiber-coupled distributed feedback laser (DFB) as the light source, Combined wavelength modulation spectroscopy and harmonic detection technique, developed a fiber-coupled white-type long-path gas absorption cell, to achieve high sensitivity detection of gas concentration. The system achieved a remote on-line monitoring of multi-component gas concentration,to meet the fire forecast need for Coal goaf area. There are obvious advantages Compared with the existing beam tube monitoring system in coal mine.

  9. Integrating Structural and Functional Imaging for Computer Assisted Detection of Prostate Cancer on Multi-Protocol In Vivo 3 Tesla MRI

    OpenAIRE

    Viswanath, Satish; Bloch, B. Nicolas; Rosen, Mark; Chappelow, Jonathan; Toth, Robert; Rofsky, Neil; Lenkinski, Robert,; Genega, Elisabeth; Kalyanpur, Arjun; Madabhushi, Anant

    2009-01-01

    Screening and detection of prostate cancer (CaP) currently lacks an image-based protocol which is reflected in the high false negative rates currently associated with blinded sextant biopsies. Multi-protocol magnetic resonance imaging (MRI) offers high resolution functional and structural data about internal body structures (such as the prostate). In this paper we present a novel comprehensive computer-aided scheme for CaP detection from high resolution in vivo multi-protocol MRI by integrati...

  10. [Total body MRI in early detection of bone metastasis and its indication in comparison to bone scan and other imaging techniques].

    Science.gov (United States)

    Luna, A; Vilanova, J C; Alcalá Mata, L

    2015-04-01

    Bone metastases are a recognized prognostic factor in patients with prostate cancer. Currently, Tc99 bone scan is the most frequently used imaging technique for their detection, showing a high sensitivity but a limited specificity. Thus, new morphological and mainly functional imaging techniques based on PET and MRI, or hybrid techniques such as PET-CT or PET-MRI have been introduced to improve metastases detection, estimation of total tumor load and for therapeutic monitoring. In this clinical scenario, total body MRI has arisen as a very promising technique in detection and therapeutic monitoring of bone metastases of prostate cancer, because it neither uses ionizing radiation nor needs the administration of contrast media. The incorporation of MR diffusion to the morphologic total body MRI protocols provides functional information, improving the sensitivity in oncological lesions detection in general and osteolytic bone metastases of PCa in particular. Its integration in protocols with morphological sequences and its quantification through ADC maps enables us to better understand metastatic bone disease patterns and their changes with different therapies. Total body D MRI enables the early classification of the response to treatment with evident advantages over other imaging techniques and the purely morphological approach with MRI. In any case, prospective and cost-effectiveness studies are necessary to establish the role of total-body D MRI in the management of patients with PCa. PMID:25948807

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-01-15

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

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

    Science.gov (United States)

    Uehara, K; Tai, H

    1992-02-20

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

  13. Experimental study on flaw detectability of remote field eddy current testing

    International Nuclear Information System (INIS)

    For the purpose of comprehending the effect in practical use of the remote field eddy current (RFEC) testing that becomes noticeable for the ISI technique of steel tubes, its flaw detectability was clarified through a model test. This study used straight and bending tubes of 3.8 mm in wall thickness and 31.8 mm in outside diameter. These tubes were inspected from their inside. After relations among the pickup coil output, coil distance, testing frequency, etc. were measured, a probe of the practical use type was manufactured to investigate its flaw detectability by means of simulated flaws. The authors discuss how it has been found that light local wall thinning on the outside surfaces can be detected by this technique and its effect in practical use can be expected with small influences due to magnetic permeability variations of tube materials, bending of tubes, etc

  14. Reversible data hiding for tampering detection in remote sensing images using histogram shifting

    Science.gov (United States)

    Serra-Ruiz, Jordi; Megias, David

    2012-10-01

    This paper presents a reversible fragile data hiding scheme for tampering detection in remote sensing images based on the histogram shifting approach. The image to be protected is divided into blocks of a reduced size and a subset of the image bands are selected for embedding. Instead of using the histogram of each separate band, the shifting process is applied to the histogram of the maximum component (or infinity norm) of the vectors obtained with the selected bands. The proposed approach is reversible and thus, the original image can be fully recovered once it has been authenticated. The method is designed to detect specific forged blocks (areas) of the protected image and is shown to succeed to detect copy and replace attacks. In addition, the experimental results, presented for the Cuprite AVIRIS image, show that the method yields extremely high transparency, with PSNR larger than 100 dB prior to reversing the scheme and recovering the original image.

  15. Remote detection of hemlock woolly adelgid infestations in southern New Hampshire and Maine

    Science.gov (United States)

    Williams, Justin P.

    The hemlock woolly adelgid (HWA) is an invasive pest damaging Eastern and Carolina hemlock on the east coast of the United States. Maine and New Hampshire are currently the northernmost front of HWA spread. Developing methods to remotely detect infested stands is paramount in monitoring the spread of this pest. The effect of HWA on hemlock needle reflectance was evaluated using laboratory spectroscopy, pigment extractions and fluorescence measurements. Hemlock habitat suitability was modeled using MaxEnt software and thirteen environmental predictor variables; overall accuracy was 68.2%. Partition modeling of multi-year (1995-2013) Landsat Thematic Mapper imagery was used to develop classification rules that detect and predict HWA infested areas (R 2 = 0.782). Overall agreement with known HWA infestations was 86.7% in conifer forests, 44.3% in mixed forests and 31.6% in deciduous forests. Targeted field surveys of fourteen stands predicted to be infested resulted in eleven new HWA detections.

  16. Noninvasive Stem Cell Labeling Using USPIO Technique and their Detection with MRI

    OpenAIRE

    Ayoob Rostamzadeh; Arash Shabani; Reza Ahadi; Mohammad Farzizadeh; Alireza Gharib; Saber Miraki

    2014-01-01

    Background: To date, several imaging techniques to track stem cells are used such as positron emission tomography (PET), single photon emission computed tomography (SPECT), Bioluminescence imaging (BLI), fluorescence imaging, CT scan and magnetic resonance imaging (MRI). Although, overall sensitivity of MRI compared to SPECT and Bioluminescence techniques are lower, but due to high spatial resolution (~100 mm), long term three-dimensional imaging capability, in vivo quick access to images in ...

  17. Whole body MRI: Improved Lesion Detection and Characterization With Diffusion Weighted Techniques

    OpenAIRE

    Attariwala, Rajpaul; Picker, Wayne

    2013-01-01

    Diffusion-weighted imaging (DWI) is an established functional imaging technique that interrogates the delicate balance of water movement at the cellular level. Technological advances enable this technique to be applied to whole-body MRI. Theory, b-value selection, common artifacts and target to background for optimized viewing will be reviewed for applications in the neck, chest, abdomen, and pelvis. Whole-body imaging with DWI allows novel applications of MRI to aid in evaluation of conditio...

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

    DEFF Research Database (Denmark)

    Duer-Jensen, A; Ejbjerg, B

    2009-01-01

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

  19. 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)

    Duer, Anne; Ejbjerg, Bo

    2008-01-01

    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.

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

    International Nuclear Information System (INIS)

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

  1. 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

  2. [Case of renal cell carcinoma with intertrabecular vertebral metastases detected f-18 fluorodeoxyglucose positron emission tomography and MRI].

    Science.gov (United States)

    Yoneyama, Shuko; Yumura, Yasushi; Koizumi, Mitsuyuki; Hanai, Takahiro; Ishida, Hiroaki; Hattori, Yusuke; Teranishi, Jyunichi; Miyoshi, Yasuhide; Kondo, Keiichi; Noguchi, Kazumi

    2014-01-01

    We report a case of renal cell carcinoma with intertrabecular vertebral metastases detected by F-18 fluorodeoxyglucose positron emission tomography (FDG-PET)/computed tomography (CT) and magnetic resonance imaging (MRI). The patient was a 40-year-old female, referred to our hospital for fever of ? 38°C, and loss of body weight. Examination showed anemia and elevated C-reactive protein (CRP). Abdominal enchanced CT showed a mass 3 cm in diameter, located on left kidney. She was diagnosed with left renal cell carcinoma (cT1aN0M0). Laparoscopic radical nephrectomy with a transabdominal approach was performed. Histological findings showed clear cell renal cell carcinoma G2?G3. Although after operation, she presented with fever of ?38°C, anemia, and elevated CRP and alkaline phosphatase. Systemic bone scan could not detect any bone metastases, but FDG-PET/CT and lumber MRI revealed cancer invasion to the bone of the whole body. Histological findings at bone biopsy showed clear cell carcinoma infiltrating the marrow space. We diagnosed the case as bone metastases of intertrabecular vertebral type. She was treated with temsirolimus,but died about five months after her first visit. Intertrabecular vertebral metastases that infiltrate the marrow space without trabecular bone alteration are not visible on radiographs or bone scans. FDG-PET/CT and MRI are more useful for diagnosis of intertrabecular vertebral metastases such as in this case. PMID:24594770

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

    Energy Technology Data Exchange (ETDEWEB)

    Jerry Myers

    2003-11-12

    Ophir Corporation was awarded a contract by the U. S. Department of Energy, National Energy Technology Laboratory under the Project Title ''Airborne, Optical Remote Sensing of Methane and Ethane for Natural Gas Pipeline Leak Detection'' on October 14, 2002. This second six-month technical report summarizes the progress made towards defining, designing, and developing the hardware and software segments of the airborne, optical remote methane and ethane sensor. The most challenging task to date has been to identify a vendor capable of designing and developing a light source with the appropriate output wavelength and power. This report will document the work that has been done to identify design requirements, and potential vendors for the light source. Significant progress has also been made in characterizing the amount of light return available from a remote target at various distances from the light source. A great deal of time has been spent conducting laboratory and long-optical path target reflectance measurements. This is important since it helps to establish the overall optical output requirements for the sensor. It also reduces the relative uncertainty and risk associated with developing a custom light source. The data gathered from the optical path testing has been translated to the airborne transceiver design in such areas as: fiber coupling, optical detector selection, gas filters, and software analysis. Ophir will next, summarize the design progress of the transceiver hardware and software development. Finally, Ophir will discuss remaining project issues that may impact the success of the project.

  4. A Dual-Mode UWB Wireless Platform with Random Pulse Length Detection for Remote Patient Monitoring

    DEFF Research Database (Denmark)

    Reyes, Carlos; Bisbe, Sergi

    2013-01-01

    This paper presents a dual-mode ultra-wideband platform for wireless Remote Patient Monitoring (RPM). Existing RPM solutions are typically based on two different hardware platforms; one responsible for medical-data monitoring and one to handle data transmission. The proposed RPM topology is based on a single hardware platform, but it is capable of both monitoring and data transmission. This is achieved by employing a new random pulse length detection method that allows data transmission by using a modulated monitoring signal. To prove the proposed concept a test system has been built, using commercial equipment, and satisfactory results are obtained.

  5. Detection and classification of different liver lesions: Comparison of Gd-EOB-DTPA-enhanced MRI versus multiphasic spiral CT in a clinical single centre investigation

    International Nuclear Information System (INIS)

    Objective: To compare the diagnostic efficacy of Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) vs. multidetector computed tomography (MDCT) for the detection and classification of focal liver lesions, differentiated also for lesion entity and size; a separate analysis of pre- and postcontrast images as well as T2-weighted MRI sequences of focal and exclusively solid lesions was integrated. Methods: Twenty-nine patients with 130 focal liver lesions underwent MDCT (64-detector-row; contrast medium iopromide; native, arterial, portalvenous, venous phase) and MRI (1.5-T; dynamic and tissue-specific phase 20 min after application of Gd-EOB-DTPA). Hepatic lesions were verified against a standard of reference (SOR). CT and MR images were independently analysed by four blinded radiologists on an ordinal 6-point-scale, determining lesion classification and diagnostic confidence. Results: Among 130 lesions, 68 were classified as malignant and 62 as benign by SOR. The detection of malignant and benign lesions differed significantly between combined and postcontrast MRI vs. MDCT; overall detection rate was 91.5% for combined MRI and 80.4% for combined MDCT (p < 0.05). Considering all four readers together, combined MDCT achieved sensitivity of 66.2%, specificity of 79.0%, and diagnostic accuracy of 72.3%; combined MRI reached superior diagnostic efficacy: sensitivity 86.8%, specificity 94.4%, accuracy 90.4% (p < 0.05). Differentiated for lesion size, in particular lesions <20 mm revealed diagnostic benefit by MRI. Postcontrast MRI also achieved higher overall sensitivity, specificity, and accuracy compared to postcontrast MDCT for focal and exclusively solid liver lesions (p < 0.05). Conclusion: Combined and postcontrast Gd-EOB-DTPA-enhanced MRI provided significantly higher overall detection rate and diagnostic accuracy, including low inter-observer variability, compared to MDCT in a single centre study

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Qu, J.-R [Department of Radiology, Affiliated Cancer Hospital, Zhengzhou University, Zhengzhou (China); Li, H.-L, E-mail: doctor_hnchr@yahoo.com.cn [Department of Radiology, Affiliated Cancer Hospital, Zhengzhou University, Zhengzhou (China); Shao, N.-N; Li, X. [Department of Radiology, Affiliated Cancer Hospital, Zhengzhou University, Zhengzhou (China); Yan, G.-L [Department of Preventive Medicine, School of Basic Medicine, Henan University of Traditional Chinese Medicine, Zhengzhou (China); Zhang, H.-K; Luo, J.-P; Zhang, S.-N; Li, Y.-L; Liu, C.-C [Department of Radiology, Affiliated Cancer Hospital, Zhengzhou University, Zhengzhou (China)

    2012-07-15

    Aim: To evaluate the added value of diffusion-weighted imaging (DWI) combined with conventional magnetic resonance imaging (MRI) in the detection of new, very small hepatocellular carcinoma lesions ({<=}1 cm) in patients with hepatocellular carcinoma following interventional therapy compared to conventional MRI alone. Materials and methods: After interventional therapy, 45 patients with hepatocellular carcinoma underwent conventional MRI and DWI with a b-value of 0 and 700 s/mm{sup 2}. Twenty-one new, small hepatocellular carcinoma lesions were confirmed in 16 patients at follow-up MRI. Two observers independently retrospectively analysed the two imaging sets in random order. The diagnostic performance using each imaging set was evaluated by received operating characteristic curve analysis. Results: Twenty-one new, very small hepatocellular carcinoma lesions found in 16 patients was confirmed as the final result. The area under the receiver operating characteristic curve of the DWI/conventional MRI combination (observer 1, 0.952; observer 2, 0.976) and conventional MRI images alone (observer 1, 0.905; observer 2, 0.905) were statistically significant. The kappa value of the DWI/conventional MRI combination was 0.884, and that of conventional MRI was 0.722. Among the 21 lesions, 100% (21/21) of the lesions were both recognized by two independent reviewers on DWI, while only 76% (16/21) and 71% (15/21) of the lesions were regarded as very small hepatocellular carcinomas on conventional MRI. Conclusion: Due to the higher detection rate of new subcentimetre lesions in hepatocellular carcinoma patients following interventional therapy, DWI could be considered complementary to conventional MRI in the diagnosis of hepatocellular carcinoma.

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

    Science.gov (United States)

    Othman, Yahia Abdelrahman

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

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

    Science.gov (United States)

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

    2013-11-01

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

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

    Directory of Open Access Journals (Sweden)

    ZHU Changming

    2015-03-01

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

  11. Pulsed laser surface fragmentation and mid-infrared laser spectroscopy for remote detection of explosives

    Science.gov (United States)

    Bauer, C.; Geiser, P.; Burgmeier, J.; Holl, G.; Schade, W.

    2006-11-01

    Stand-off technology for the remote detection of explosives and their traces on contaminated surfaces is a field of research that has recently gained much interest. Optical methods are well established in applications for counterterrorism because they facilitate analysis without contact between human being and hazardous materials. In this paper, to our knowledge for the first time, a remote stand-off detection system is developed by combination of pulsed laser fragmentation and pulsed mid-infrared laser absorption spectroscopy. Since the absorption of explosives is more efficient for infrared wavelengths laser radiation in the eye safe region around ?=1.47 ?m rather than the conventional Nd:YAG laser line at ?=1.06 ?m is preferred for the fragmentation. Generated product gases such as nitric oxide are probed by a synchronized distributed feedback quantum cascade laser (DFB-QCL) at ??5.3 ?m. The ratio of NO and NO2 is a measure to distinguish between energetic and non-energetic materials.

  12. Island Coastline Change Detection Based on Image Processing and Remote Sensing

    Directory of Open Access Journals (Sweden)

    Majed Bouchahma

    2012-04-01

    Full Text Available As an island ecosystem, Djerba, a region of Tunisia located on the southern shore of the Mediterranean Sea, is characterized by limited natural resources and threatened by land degradation due to rapid socio-economic development and heavy human-induced changes to the landscape. The objective of this study is to build a system based on computer vision and remote sensing data for monitoring changes in the coastal zones of an island. We employed monthly Landsat Thematic Mapper (TM satellite images of the study area ranging from 1984 to 2009. The images were preprocessed using the Speeded Up Robust Features (SURF algorithm to superimpose remote sensing images at exactly the same coordinates. We then used two comparison techniques to auto-validate the detection of changes. The first technique is based on a window-to-window comparison of the coastal zones and the second technique compares shoreline changes using edge detection. Three highly affected regions were identified. The Bin El-Ouidiane (in the southeast and Rass Errmal (in the north regions underwent deposition during the study period, whereas the region of Rass El Kastil (in the north underwent high erosion.

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

    Directory of Open Access Journals (Sweden)

    Lei Lin

    2011-02-01

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

  14. Detection and monitoring of super sandstorm and its impacts on Arabian Sea-Remote sensing approach

    Science.gov (United States)

    Kunte, Pravin D.; M. A., Aswini

    2015-06-01

    The present study addresses an intense sandstorm event over the Persian Gulf and its transport over the Arabian Sea region and the Indian sub-continent using satellite observations and measurements. MODIS data are used to analyze the temporal variation of the dust events that occurred from 17 to 24 March 2012 with the strongest intensity on 20 March over the Arabian Sea. MODIS images are examined to provide an independent assessment of dust presence and plume location and its migration over the Arabian Sea to the Indian sub-continent. Dust enhancement and dust detection procedure is attempted to demarcate the dust event. Dust source, formation, transportation path, and dissipation is studied using source-back-tracking, surface wind, and surface pressure, wind speed and direction, geo-potential height for different pressure level, and remote sensing methods. Finally, an attempt is made to investigate the impact of super sandstorm on the Arabian Sea by studying sea surface temperature and chlorophyll a variability during the events. It is noted that sea surface temperature is decreased and chlorophyll a concentration increased during the post-event period. The present study demonstrates the use of remote sensing data and geospatial techniques in detecting and mapping of dust events and monitoring dust transport along specific regional transport pathways over land and ocean.

  15. Remote detection of mental workload changes using cardiac parameters assessed with a low-cost webcam.

    Science.gov (United States)

    Bousefsaf, Frédéric; Maaoui, Choubeila; Pruski, Alain

    2014-10-01

    We introduce a new framework for detecting mental workload changes using video frames obtained from a low-cost webcam. Image processing in addition to a continuous wavelet transform filtering method were developed and applied to remove major artifacts and trends on raw webcam photoplethysmographic signals. The measurements are performed on human faces. To induce stress, we have employed a computerized and interactive Stroop color word test on a set composed by twelve participants. The electrodermal activity of the participants was recorded and compared to the mental workload curve assessed by merging two parameters derived from the pulse rate variability and photoplethysmographic amplitude fluctuations, which reflect peripheral vasoconstriction changes. The results exhibit strong correlation between the two measurement techniques. This study offers further support for the applicability of mental workload detection by remote and low-cost means, providing an alternative to conventional contact techniques. PMID:25150821

  16. 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

  17. Remote detection of incessant slow VT with an ICD capable of home monitoring.

    Science.gov (United States)

    Siaplaouras, Stephanos; Buob, Axel; Neuberger, Hans Ruprecht; Mewis, Christian

    2006-07-01

    In this case report, we present a 57-year-old patient who suffered from incessant slow ventricular tachycardia because of a change in therapy 2 weeks after the implantation of an implantable cardioverter defibrillator (ICD) with Home Monitoring (HM). HM is a fully automatic and wireless system capable of transmitting device data including episode counters. The patient had mild symptoms with only short episodes of dizziness and would not have contacted the primary care centre. Due to HM, the arrhythmia was detected before the next routine follow-up, and the patient was seen the next day. HM made it possible to adjust the dosage of the newly established beta-blocker treatment in an outpatient setting and avoid hospitalization. HM yields the potential for remote detection of arrhythmias in ICD recipients, allowing alterations in device programming or medication. PMID:16760231

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

    Directory of Open Access Journals (Sweden)

    Guomin Li

    2013-07-01

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

  19. Integrated microchip incorporating atomic magnetometer and microfluidic channel for NMR and MRI

    Science.gov (United States)

    Ledbetter, Micah P. (Oakland, CA); Savukov, Igor M. (Los Alamos, NM); Budker, Dmitry (El Cerrito, CA); Shah, Vishal K. (Plainsboro, NJ); Knappe, Svenja (Boulder, CO); Kitching, John (Boulder, CO); Michalak, David J. (Berkeley, CA); Xu, Shoujun (Houston, TX); Pines, Alexander (Berkeley, CA)

    2011-08-09

    An integral microfluidic device includes an alkali vapor cell and microfluidic channel, which can be used to detect magnetism for nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI). Small magnetic fields in the vicinity of the vapor cell can be measured by optically polarizing and probing the spin precession in the small magnetic field. This can then be used to detect the magnetic field of in encoded analyte in the adjacent microfluidic channel. The magnetism in the microfluidic channel can be modulated by applying an appropriate series of radio or audio frequency pulses upstream from the microfluidic chip (the remote detection modality) to yield a sensitive means of detecting NMR and MRI.

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

    OpenAIRE

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

    2010-01-01

    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 sequence...

  1. A suspicious breast lesion detected by dynamic contrast-enhanced MRI and pathologically confirmed as capillary hemangioma: A case report and literature review

    International Nuclear Information System (INIS)

    Breast capillary hemangioma is a type of benign vascular tumor which is rarely seen. Little is known about its presentation on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Here, we describe a case of suspicious breast lesion detected by DCE-MRI and pathologically confirmed as capillary hemangioma. Our case indicates that a small mass with a superficial location, clear boundary, and homogeneous enhancement on DCE-MRI indicates the possible diagnosis of hemangioma, whereby even the lesion presents a washout type curve.

  2. A suspicious breast lesion detected by dynamic contrast-enhanced MRI and pathologically confirmed as capillary hemangioma: A case report and literature review

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Lian He; Li, Qing Chang; Xu, Hong Tao; Wang, Xin; Wang, En Hua [The First Affiliated Hospital and College of Basic Medical Sciences, China Medical University, Shenyang (China); Ma, Shuang [Dept. of Neurology, Sheng Jing Hospital of China Medical University, Shenyang (China)

    2013-12-15

    Breast capillary hemangioma is a type of benign vascular tumor which is rarely seen. Little is known about its presentation on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Here, we describe a case of suspicious breast lesion detected by DCE-MRI and pathologically confirmed as capillary hemangioma. Our case indicates that a small mass with a superficial location, clear boundary, and homogeneous enhancement on DCE-MRI indicates the possible diagnosis of hemangioma, whereby even the lesion presents a washout type curve.

  3. Optimizing Patient Population for MP-MRI and Fusion Biopsy for Prostate Cancer Detection.

    Science.gov (United States)

    Frye, Thomas P; Pinto, Peter A; George, Arvin K

    2015-07-01

    The diagnosis and treatment of prostate cancer continue to evolve with advances in science and technology. The utilization of multiparametric MRI (mp-MRI) to identify lesions in the prostate has given clinicians the ability to visualize malignancy in the prostate with greater confidence. With this new ability came the advancement of fusion biopsy platforms, which allow for direct targeting of these lesions. As with any new technology in medicine, the proper use of these modalities and how they fit into current clinical practice need to be addressed. This review summarizes the current knowledge on how to best optimize which men undergo mp-MRI and fusion biopsies both in the screening and treatment settings. PMID:26063625

  4. Gadolinium enhancement: improved MRI detection of retinoblastoma extension into the optic nerve

    International Nuclear Information System (INIS)

    We performed T1-, T2-, proton density-weighted, and T1-weighted gadolinium-enhanced MRI on 24 patients with retinoblastoma, using a 1.5 T superconducting unit and head and orbital surface coil imaging. All patients underwent a complete ophthalmologic examination, including B-scan ultrasonography. CT was performed on 10 of 24 patients. Pathologic correlation was obtained in 18 patients who required enucleation. Contrast-enhanced T1-weighted MRI with fat suppression was the sequence most sensitive to optic nerve extension and provided the greatest differentiation between tumor and uninvolved extrascleral tissue. Retinoblastoma demonstrated contrast enhancement. (orig.). With 3 figs., 1 tab

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

    International Nuclear Information System (INIS)

    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 T1-weighted images low signal intensity changes of the pars interarticularis proved that bony fusion had been attained with conservative therapy. (author)

  6. CLINICALLY LOCALIZED PROSTATE CANCER: CAPACITIES OF MATRIX COIL MRI TO DETECT MINIMAL EXTRACAPSULAR TUMOR SPREAD

    Directory of Open Access Journals (Sweden)

    E. A. Petrova

    2014-08-01

    Full Text Available Retrospective assessment of preoperative magnetic resonance imaging (MRI data in 37 patients with prostate cancer, who had undergone radical prostatectomy, established the most diagnostically valuable MRI signs of minimal extracapsular spread (ECS: asymmetry of neurovascular fascicles (72 % accuracy, 93 % sensitivity, 77 % specificity, 73 % positive and 94% negative predictive values and iron outline deformity/irregularity (66/80/64/60/82 %, respectively; as well as their higher diagnostic efficiency versus the clinical and laboratory predictors of ECS: total Gleason scores (58/87/55/57/86 %, respectively and serum PSA levels (uninformative, which permits their consideration while choosing a more or less radical prostatectomy modality.

  7. Utilizing Fast Spin Echo MRI to Reduce Image Artifacts and Improve Implant/Tissue Interface Detection in Refractory Parkinson's Patients with Deep Brain Stimulators

    OpenAIRE

    Sarkar, Subhendra N.; Sarkar, Pooja R.; Efstathios Papavassiliou; Rojas, Rafael R.

    2014-01-01

    Introduction:. In medically refractory Parkinson's disease (PD) deep-brain stimulation (DBS) is an effective therapeutic tool. Postimplantation MRI is important in assessing tissue damage and DBS lead placement accuracy. We wanted to identify which MRI sequence can detect DBS leads with smallest artifactual signal void, allowing better tissue/electrode edge conspicuity. Methods:. Using an IRB approved protocol 8 advanced PD patients were imaged within MR conditional safety guidelines at low R...

  8. In vivo detection of microscopic anisotropy using quadruple pulsed-field gradient (qPFG) diffusion MRI on a clinical scanner

    OpenAIRE

    Avram, Alexandru V.; Özarslan, Evren; Sarlls, Joelle E.; Basser, Peter J

    2012-01-01

    We report our design and implementation of a quadruple pulsed-field gradient (qPFG) diffusion MRI pulse sequence on a whole-body clinical scanner and demonstrate its ability to non-invasively detect restriction-induced microscopic anisotropy in human brain tissue. The microstructural information measured using qPFG diffusion MRI in white matter complements that provided by diffusion tensor imaging (DTI) and exclusively characterizes diffusion of water trapped in microscopic compartments with ...

  9. Laboratory insights into the detection of surface biosignatures by remote-sensing techniques

    Science.gov (United States)

    Poch, O.; Pommerol, A.; Jost, B.; Roditi, I.; Frey, J.; Thomas, N.

    2014-03-01

    With the progress of direct imaging techniques, it will be possible in the short or long-term future to retrieve more efficiently the information on the physical properties of the light reflected by rocky exoplanets (Traub et al., 2010). The search for visible-infrared absorption bands of peculiar gases (O2, CH4 etc.) in this light could give clues for the presence of life (Kaltenegger and Selsis, 2007). Even more uplifting would be the direct detection of life itself, on the surface of an exoplanet. Considering this latter possibility, what is the potential of optical remote-sensing methods to detect surface biosignatures? Reflected light from the surface of the Earth exhibits a strong surface biosignature in the form of an abrupt change of reflectance between the visible and infrared range of the spectrum (Seager et al., 2005). This spectral feature called "vegetation red-edge" is possibly the consequence of biological evolution selecting the right chemical structures enabling the plants to absorb the visible energy, while preventing them from overheating by reflecting more efficiently the infrared. Such red-edge is also found in primitive photosynthetic bacteria, cyanobacteria, that colonized the surface of the Earth ocean and continents billions of years before multicellular plants (Knacke, 2003). If life ever arose on an Earth-like exoplanet, one could hypothesize that some form of its surface-life evolves into similar photo-active organisms, also exhibiting a red-edge. In this paper, we will present our plan and preliminary results of a laboratory study aiming at precising the potentiality of remote sensing techniques in detecting such surface biosignatures. Using equipment that has been developed in our team for surface photometry studies (Pommerol 2011, Jost 2013, Pommerol 2013), we will investigate the reflectance spectra and bidirectional reflectance function of soils containing bacteria such as cyanobacteria, in various environmental conditions. We will also present our plan to incorporate polarization measurements, and particularly circular polarization, because it can be a marker of homochirality, which is supposed to be a universal property of life. Finally, the analyses of both biotic and abiotic materials will help to assess if (or in which peculiar conditions) remote sensing techniques can discriminate between false positive and strong biomarkers. Ultimately, these laboratory data can serve as reference data to guide and interpret future observations, paving the way for the detection of life on distant exoplanets.

  10. Novel MRI methodology to detect human whole-brain connectivity changes after ingestion of fructose or glucose

    Science.gov (United States)

    Tsao, Sinchai; Wilkins, Bryce; Page, Kathleen A.; Singh, Manbir

    2012-03-01

    A novel MRI protocol has been developed to investigate the differential effects of glucose or fructose consumption on whole-brain functional brain connectivity. A previous study has reported a decrease in the fMRI blood oxygen level dependent (BOLD) signal of the hypothalamus following glucose ingestion, but due to technical limitations, was restricted to a single slice covering the hypothalamus, and thus unable to detect whole-brain connectivity. In another previous study, a protocol was devised to acquire whole-brain fMRI data following food intake, but only after restricting image acquisition to an MR sampling or repetition time (TR) of 20s, making the protocol unsuitable to detect functional connectivity above 0.025Hz. We have successfully implemented a continuous 36-min, 40 contiguous slices, whole-brain BOLD acquisition protocol on a 3T scanner with TR=4.5s to ensure detection of up to 0.1Hz frequencies for whole-brain functional connectivity analysis. Human data were acquired first with ingestion of water only, followed by a glucose or fructose drink within the scanner, without interrupting the scanning. Whole-brain connectivity was analyzed using standard correlation methodology in the 0.01-0.1 Hz range. The correlation coefficient differences between fructose and glucose ingestion among targeted regions were converted to t-scores using the water-only correlation coefficients as a null condition. Results show a dramatic increase in the hypothalamic connectivity to the hippocampus, amygdala, insula, caudate and the nucleus accumben for fructose over glucose. As these regions are known to be key components of the feeding and reward brain circuits, these results suggest a preference for fructose ingestion.

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

    Energy Technology Data Exchange (ETDEWEB)

    Schmid-Tannwald, Christine; Schmid-Tannwald, Christoph M.; Neumann, Ralph; Nikolaou, Konstantin; Schramm, Nicolai; Reiser, Maximilian F.; Rist, Carsten [Ludwig Maximilians University Hospital Munich, Institute for Clinical Radiology, Munich (Germany); Morelli, John N. [Scott and White Hospital Temple, Department of Radiology, Temple, TX (United States); Haug, Alexander R.; Jansen, Nathalie [Ludwig Maximilians University Hospital Munich, Department of Nuclear Medicine, Munich (Germany)

    2013-06-15

    The aim of the study was to evaluate contrast-enhanced MRI, diffusion-weighted MRI (DW MRI), and {sup 68}Ga-DOTATATE positron emission tomography (PET)/CT in the detection of intermediate to well-differentiated neuroendocrine tumors (NET) of the pancreas. Eighteen patients with pathologically proven pancreatic NET who underwent MRI including DW MRI and PET/CT within 6 weeks of each other were included in this retrospective study. Two radiologists evaluated T2-weighted (T2w), T2w + DW MRI, T2w + contrast-enhanced T1-weighted (CE T1w) MR images, and PET/CT for NET detection. The sensitivity and level of diagnostic confidence were compared among modalities using McNemar's test and a Wilcoxon signed rank test. Apparent diffusion coefficients (ADC) of pancreatic NETs and normal pancreatic tissue were compared with Student's t test. Of the NETs, 8/23 (34.8 %) and 9/23 (39.1 %) were detected on T2w images by observers 1 and 2, respectively. Detection rates improved significantly by combining T2w images with DW MRI (observer 1: 14/23 = 61 %; observer 2: 15/23 = 65.2 %; p < 0.05) or CE T1w images (observer 1: 14/23 = 61 %; observer 2: 15/23 = 65.2 %; p < 0.05). Detection rates of pancreatic NET with PET/CT (both observers: 23/23 = 100 %) were statistically significantly higher than with MRI (p < 0.05). The mean ADC value of NET (1.02 {+-} 0.26 x 10{sup -3} mm{sup 2}/s) was statistically significantly lower than that of normal pancreatic tissue (1.48 {+-} 0.39 x 10{sup -3} mm{sup 2}/s). DW MRI is a valuable adjunct to T2w imaging and comparable to CE T1w imaging in pancreatic NET detection, quantitatively differentiating between NET and normal pancreatic tissue with ADC measurements. {sup 68}Ga-DOTATATE PET/CT is more sensitive than MRI in the detection of pancreatic NET. (orig.)

  12. 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 imx) 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)

  13. 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 anaired 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

  14. An analysis of LULC change detection using remotely sensed data; A Case study of Bauchi City

    Science.gov (United States)

    Kafi, K. M.; Shafri, H. Z. M.; Shariff, A. B. M.

    2014-06-01

    Bauchi is one of the cities in the north eastern part of Nigeria that has witnessed tremendous expansion as a result of rapid urbanization. For the past decade, the city has been known to be relatively small both in size and population. But today, Bauchi is one of the fastest growing cities in northern Nigeria. Therefore, it is paramount to detect the nature and magnitude of these changes in order to determine its direction of future expansion. To achieve that, Remotely Sensed data from Landsat 7 ETM+ and Landsat 8 were utilized for the purpose of LULC change detection in Bauchi city. Landsat 7 image of 2003 and Landsat 8 image of 2013 were obtained for the purpose of the study. Three change detection algorithms were used to detect areas of change. They include supervised, unsupervised and post classification comparison. While the unsupervised classification was found to be less effective, the supervised classification produced good results with overall accuracies of 93.5% and 89.7% for the 2003 and 2013 respectively. Finally, "from-to" change was obtained using the post classification comparism.

  15. Intrusion detection capabilities of smart video: Collaborative efforts to improve remote monitoring for safeguards surveillance

    International Nuclear Information System (INIS)

    Collaborative efforts between the International Projects Division (IPD) of the Department of Advanced Technology at Brookhaven National Laboratory, Aquila Technologies Group, Inc. (Aquila), and the General Physics Institute (GPI) in Moscow have developed object recognition technologies to provide real-time intrusion detection capabilities for Aquila''s GEMINI Digital Surveillance System. The research, development and testing for integrating enhanced surveillance capabilities into Aquila''s GEMINI system will receive support from the US Industry Coalition (USIC), an initiative funded by the Initiatives for Proliferation Prevention (IPP), in the coming year. Oversight of the research and development effort is being provided by the IPD staff to ensure that the technical standards of safeguards systems for use by the International Atomic Energy Agency (IAEA) are met. The scientific expertise at GPI is providing breakthroughs in the realm of motion detection for surveillance. Aquila''s contribution to the project focuses on the integration of authenticated digital camera technology for front-end detection. This project illustrates how the application of technology can increase efficiency and reliability of remote monitoring, as well as the timely detection of Safeguards-significant events

  16. A generic discriminative part-based model for geospatial object detection in optical remote sensing images

    Science.gov (United States)

    Zhang, Wanceng; Sun, Xian; Wang, Hongqi; Fu, Kun

    2015-01-01

    Detecting geospatial objects with complex structure has been explored for years and it is still a challenging task in high resolution optical remote sensing images (RSI) interpretation. In this paper, we mainly focus on the problem of rotation variance in detecting geospatial objects and propose a generic discriminative part-based model (GDPBM) to build a practical object detection framework. In our model, a geospatial object with arbitrary orientation is divided into several parts and represented via three terms: the appearance features, the spatial deformation features and the rotation deformation features. The appearance features characterize the local patch appearance of the object and parts, and we propose a new kind of rotation invariant feature to represent the appearance using the local intensity gradients. The spatial deformation features capture the geometric deformation of parts by representing the relative displacements among parts. The rotation deformation features define the pose variances of the parts relative to the objects based on their dominant orientations. In generating the two deformation features, we introduce the statistic methods to encode the features in the category level. Concatenating the three terms of the features, a classifier based on the support vector machine is learned to detect geospatial objects. In the experiments, two datasets in optical RSI are used to evaluate the performance of our model and the results demonstrate its robustness and effectiveness.

  17. Detection of irregular, transient fMRI activity in normal controls using 2dTCA: comparison to event-related analysis using known timing

    OpenAIRE

    Morgan, Victoria L.; Gore, John C.

    2009-01-01

    When events occur spontaneously during the acquisition of a series of images, traditional modeling methods for detecting functional MRI activation detection cannot be employed. The two-dimensional Temporal Clustering Algorithm, 2dTCA, has been shown to accurately detect random, transient activations in computer simulations without the use of known event timings. In this study we applied the 2dTCA technique to detect the timings and spatial locations of sparse, irregular, transient activations...

  18. Whole-body MRI for the detection of bone marrow involvement in lymphoma: prospective study in 116 patients and comparison with FDG-PET

    International Nuclear Information System (INIS)

    To assess and compare the value of whole-body MRI with FDG-PET for detecting bone marrow involvement in lymphoma. A total of 116 patients with newly diagnosed lymphoma prospectively underwent whole-body MRI and blind bone marrow biopsy (BMB) of the posterior iliac crest. Of 116 patients, 80 also underwent FDG-PET. Patient-based sensitivities of whole-body MRI for detecting bone marrow involvement were calculated using BMB as reference standard and compared with FDG-PET in aggressive and indolent lymphomas separately. Sensitivity of whole-body MRI in all lymphomas was 45.5 % [95 % confidence interval (CI): 29.8-62.0 %]. Sensitivity of whole-body MRI in aggressive lymphoma [88.9 % (95 % CI: 54.3-100 %)] was significantly higher (P = 0.0029) than that in indolent lymphoma [23.5 % (95 % CI: 9.1-47.8 %)]. Sensitivity of FDG-PET in aggressive lymphoma [83.3 % (95 % CI: 41.8-98.9 %)] was also significantly higher (P = 0.026) than that in indolent lymphoma [12.5 % (95 % CI: 0-49.2 %)]. There were no significant differences in sensitivity between whole-body MRI and FDG-PET (P = 1.00) Sensitivity of whole-body MRI for detecting lymphomatous bone marrow involvement is too low to (partially) replace BMB. Sensitivity of whole-body MRI is significantly higher in aggressive lymphoma than in indolent lymphoma and is equal to FDG-PET in both entities. (orig.)

  19. Usefulness of MRI detection of cervical spine and brain injuries in the evaluation of abusive head trauma

    International Nuclear Information System (INIS)

    In the evaluation of children younger than 3 years with intracranial hemorrhage it can be difficult to determine whether the cause of hemorrhage was traumatic, and if so, whether abusive head trauma (AHT) is a possibility. Cervical spine MRI is not a routine part of the nationally recommended imaging workup for children with suspected abusive head trauma. There is increasing evidence that spinal injuries are found at autopsy or MRI in abused children. However the prevalence of cervical spine injuries in children evaluated for abusive head trauma is unknown. We sought to determine both the incidence and the spectrum of cervical spine and brain injuries in children being evaluated for possible abusive head trauma. We also examined the relationship between cervical and brain MRI findings and selected study outcome categories. This study is a 3-year retrospective review of children evaluated for abusive head trauma. Inclusion criteria were: children with head trauma seen at our institution between 2008 and 2010, age younger than 36 months, availability of diagnostic-quality brain and cervical spine MRI, and child abuse team involvement because abusive head trauma was a possibility. A child abuse pediatrician and pediatric radiologists, all with board certification, were involved in data collection, image interpretation and data analysis. Statistical analysis was performed using Stata v12.1. The study included 74 children (43 boys, 31 girls) with a mean age of 164 days (range, 20-679 days). Study outcomes were categorized as: n = 26 children with accidental head trauma, n = 38 with abusive head trauma (n = 18 presumptive AHT, n = 20 suspicious for AHT), and n = 10 with undefined head trauma. We found cervical spine injuries in 27/74 (36%) children. Most cervical spine injuries were ligamentous injuries. One child had intrathecal spinal blood and two had spinal cord edema; all three of these children had ligamentous injury. MRI signs of cervical injury did not show a statistically significant relationship with a study outcome of abusive head trauma or help discriminate between accidental and abusive head trauma. Of the 30 children with supratentorial brain injury, 16 (53%) had a bilateral hypoxic-ischemic pattern. There was a statistically significant relationship between bilateral hypoxic-ischemic brain injury pattern and abusive head trauma (P < 0.05). In addition, the majority (81%) of children with bilateral hypoxic-ischemic brain injuries had cervical injuries. Although detection of cervical spine injuries by MRI does not discriminate between accidental and abusive head trauma, it can help to distinguish a traumatic from non-traumatic intracranial subdural hemorrhage. Cervical MRI should be considered in children with acute intracranial bleeds and otherwise non-contributory history, physical examination and ophthalmological findings. There is a statistically significant relationship between diffuse hypoxic-ischemic brain injury patterns and abusive head trauma. The high incidence of cervical injuries in children with hypoxic-ischemic injuries suggests a causal relationship. Overall, increased utilization of brain and spine MRI in children being evaluated for abusive head trauma can be helpful. (orig.)

  20. Usefulness of MRI detection of cervical spine and brain injuries in the evaluation of abusive head trauma

    Energy Technology Data Exchange (ETDEWEB)

    Kadom, Nadja [Children' s National Medical Center, Department of Diagnostic Imaging and Radiology, Washington, DC (United States); Boston University Medical Center, Boston, MA (United States); Khademian, Zarir; Vezina, Gilbert; Shalaby-Rana, Eglal [Children' s National Medical Center, Department of Diagnostic Imaging and Radiology, Washington, DC (United States); Rice, Amy [Independent Consultant (Biostatistics), Chevy Chase, MD (United States); Hinds, Tanya [Children' s National Medical Center, Child and Adolescent Protection Center, Washington, DC (United States)

    2014-07-15

    In the evaluation of children younger than 3 years with intracranial hemorrhage it can be difficult to determine whether the cause of hemorrhage was traumatic, and if so, whether abusive head trauma (AHT) is a possibility. Cervical spine MRI is not a routine part of the nationally recommended imaging workup for children with suspected abusive head trauma. There is increasing evidence that spinal injuries are found at autopsy or MRI in abused children. However the prevalence of cervical spine injuries in children evaluated for abusive head trauma is unknown. We sought to determine both the incidence and the spectrum of cervical spine and brain injuries in children being evaluated for possible abusive head trauma. We also examined the relationship between cervical and brain MRI findings and selected study outcome categories. This study is a 3-year retrospective review of children evaluated for abusive head trauma. Inclusion criteria were: children with head trauma seen at our institution between 2008 and 2010, age younger than 36 months, availability of diagnostic-quality brain and cervical spine MRI, and child abuse team involvement because abusive head trauma was a possibility. A child abuse pediatrician and pediatric radiologists, all with board certification, were involved in data collection, image interpretation and data analysis. Statistical analysis was performed using Stata v12.1. The study included 74 children (43 boys, 31 girls) with a mean age of 164 days (range, 20-679 days). Study outcomes were categorized as: n = 26 children with accidental head trauma, n = 38 with abusive head trauma (n = 18 presumptive AHT, n = 20 suspicious for AHT), and n = 10 with undefined head trauma. We found cervical spine injuries in 27/74 (36%) children. Most cervical spine injuries were ligamentous injuries. One child had intrathecal spinal blood and two had spinal cord edema; all three of these children had ligamentous injury. MRI signs of cervical injury did not show a statistically significant relationship with a study outcome of abusive head trauma or help discriminate between accidental and abusive head trauma. Of the 30 children with supratentorial brain injury, 16 (53%) had a bilateral hypoxic-ischemic pattern. There was a statistically significant relationship between bilateral hypoxic-ischemic brain injury pattern and abusive head trauma (P < 0.05). In addition, the majority (81%) of children with bilateral hypoxic-ischemic brain injuries had cervical injuries. Although detection of cervical spine injuries by MRI does not discriminate between accidental and abusive head trauma, it can help to distinguish a traumatic from non-traumatic intracranial subdural hemorrhage. Cervical MRI should be considered in children with acute intracranial bleeds and otherwise non-contributory history, physical examination and ophthalmological findings. There is a statistically significant relationship between diffuse hypoxic-ischemic brain injury patterns and abusive head trauma. The high incidence of cervical injuries in children with hypoxic-ischemic injuries suggests a causal relationship. Overall, increased utilization of brain and spine MRI in children being evaluated for abusive head trauma can be helpful. (orig.)

  1. AIRBORNE, OPTICAL REMOTE SENSING OF METHANE AND ETHANE FOR NATURAL GAS PIPLINE LEAK DETECTION

    Energy Technology Data Exchange (ETDEWEB)

    Jerry Myers

    2004-05-12

    Ophir Corporation was awarded a contract by the U. S. Department of Energy, National Energy Technology Laboratory under the Project Title ''Airborne, Optical Remote Sensing of Methane and Ethane for Natural Gas Pipeline Leak Detection'' on October 14, 2002. The third six-month technical report contains a summary of the progress made towards finalizing the design and assembling the airborne, remote methane and ethane sensor. The vendor has been chosen and is on contract to develop the light source with the appropriate linewidth and spectral shape to best utilize the Ophir gas correlation software. Ophir has expanded upon the target reflectance testing begun in the previous performance period by replacing the experimental receiving optics with the proposed airborne large aperture telescope, which is theoretically capable of capturing many times more signal return. The data gathered from these tests has shown the importance of optimizing the fiber optic receiving fiber to the receiving optic and has helped Ophir to optimize the design of the gas cells and narrowband optical filters. Finally, Ophir will discuss remaining project issues that may impact the success of the project.

  2. Photonuclear Reaction Studies at HI?S: Developing the Science of Remote Detection of Nuclear Materials

    Science.gov (United States)

    Howell, C. R.

    2015-10-01

    Development of gamma-ray beam interrogation technologies for remote detection of special nuclear materials and isotope analysis requires comprehensive databases of nuclear structure information and gamma-ray induced nuclear reaction observables. Relevant nuclear structure details include the energy, spin and parity of excited states that have significant probability for electromagnetic transition from the ground state, i.e, the angular momentum transferred in the reaction is ?l ? 2. This talk will report recent Nuclear Resonance Fluorescence (NRF) measurements to identify and characterize new low-spin states in actinide nuclei at energies from 1 to 4 MeV, which is the energy range most important for remote analysis methods. These measurements are carried out using the nearly mono-energetic linearly polarized gamma-ray beam at the High Intensity Gamma-ray Source (HI?S) at the Triangle Universities Nuclear Laboratory. Also, studies of the (?, n) reaction on a variety of nuclei with linearly polarized beams at HI?S indicate that this reaction might be used to discern between fissile and non-fissile materials. This work will be described. In addition, an overview will be given of a concept for a next generation laser Compton-backing scattering gamma-ray source to be implemented as an upgrade to increase the beam intensity at HI?S by more than an order of magnitude.

  3. Detecting Alpine landforms from remotely sensed imagery. A pilot study in the Bavarian Alps

    Science.gov (United States)

    Schneevoigt, Nora Jennifer; van der Linden, Sebastian; Thamm, Hans-Peter; Schrott, Lothar

    2008-01-01

    This study investigates the suitability of remote sensing for detecting rock and sediment storage areas in the Reintal subcatchment (17 km 2) east of Zugspitze, Germany. First, characteristic features of Alpine landforms such as curvature, process coupling or type of deposited sediment were compiled. Based on this, a landform classification was performed: topographical information from a digital elevation model (DEM) and spectral data from an ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) satellite scene were classified using a multiscale, object-oriented approach comprising four differently scaled levels. The complex decision-tree hierarchy is based for the most part on fuzzy membership functions and to a lesser extent on the hard nearest neighbour classifier. The results show that both an identification of the present-day pattern of storage types and the classification of geomorphologic units, also with regard to their activity status and complexity, is largely possible. Moreover, the methodology developed in this study permits a first assessment of the upper regions of the study area which could not be included in any previous survey because of their inaccessibility. Coherent landform classification using remote sensing methods, as developed in this study, constitutes a promising scientific approach, especially with regard to the enhanced spatial and spectral resolution of modern satellite systems.

  4. Repeat Prostate Biopsy Strategies after Initial Negative Biopsy: Meta-Regression Comparing Cancer Detection of Transperineal, Transrectal Saturation and MRI Guided Biopsy

    Science.gov (United States)

    Nelson, Adam W.; Harvey, Rebecca C.; Parker, Richard A.; Kastner, Christof; Doble, Andrew; Gnanapragasam, Vincent J.

    2013-01-01

    Introduction There is no consensus on how to investigate men with negative transrectal ultrasound guided prostate biopsy (TRUS-B) but ongoing suspicion of cancer. Three strategies used are transperineal (TP-B), transrectal saturation (TS-B) and MRI-guided biopsy (MRI-B). We compared cancer yields of these strategies. Methods Papers were identified by search of Pubmed, Embase and Ovid Medline. Included studies investigated biopsy diagnostic yield in men with at least one negative TRUS-B and ongoing suspicion of prostate cancer. Data including age, PSA, number of previous biopsy episodes, number of cores at re-biopsy, cancer yield, and Gleason score of detected cancers were extracted. Meta-regression analyses were used to analyse the data. Results Forty-six studies were included; 12 of TS-B, 14 of TP-B, and 20 of MRI-B, representing 4,657 patients. Mean patient age, PSA and number of previous biopsy episodes were similar between the strategies. The mean number of biopsy cores obtained by TP-B and TS-B were greater than MRI-B. Cancer detection rates were 30·0%, 36·8%, and 37·6% for TS-B, TP-B, and MRI-B respectively. Meta-regression analysis showed that MRI-B had significantly higher cancer detection than TS-B. There were no significant differences however between MRI-B and TP-B, or TP-B and TS-B. In a sensitivity analysis incorporating number of previous biopsy episodes (36 studies) the difference between MRI-B and TP-B was not maintained resulting in no significant difference in cancer detection between the groups. There were no significant differences in median Gleason scores detected comparing the three strategies. Conclusions In the re-biopsy setting, it is unclear which strategy offers the highest cancer detection rate. MRI-B may potentially detect more prostate cancers than other modalities and can achieve this with fewer biopsy cores. However, well–designed prospective studies with standardised outcome measures are needed to accurately compare modalities and define an optimum re-biopsy approach. PMID:23460864

  5. Land surface phenology detection with multisource remote sensing data: a comparative analysis

    Science.gov (United States)

    Lu, Linlin; Wang, Cuizhen; Guo, Huadong; Zhang, Xi; Sui, Yue

    2014-11-01

    Vegetation phenology reveals the response of vegetation to global climate change. The time series of remote sensing data have been applied to generate land surface pheology and vegetation seasonality information. In this study, land surface phenology was detected from time series of radar backscatter data from 2003 to 2007 and compared with phenological metrics derived from SPOT VEGETATION NDVI and MODIS land cover dynamic product across Australia. An asymmetric Gaussian method was used to extract phenological metrics, the start of season (SOS) and the end of season (EOS) from the time series. Comparing the spatial pattern of average SOS and EOS from the three datasets, similar spatial pattern are mapped across western and southeastern Australia. However, different phenological patterns are captured in the tropical ecosystems of northern and eastern Australia. These results showed the potential of microwave data in monitoring vegetation dynamics as complementary phenological information.

  6. 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.

  7. Hot-Carrier Seebeck Effect: Diffusion and Remote Detection of Hot Carriers in Graphene.

    Science.gov (United States)

    Sierra, Juan F; Neumann, Ingmar; Costache, Marius V; Valenzuela, Sergio O

    2015-06-10

    We investigate hot carrier propagation across graphene using an electrical nonlocal injection/detection method. The device consists of a monolayer graphene flake contacted by multiple metal leads. Using two remote leads for electrical heating, we generate a carrier temperature gradient that results in a measurable thermoelectric voltage VNL across the remaining (detector) leads. Due to the nonlocal character of the measurement, VNL is exclusively due to the Seebeck effect. Remarkably, a departure from the ordinary relationship between Joule power P and VNL, VNL ? P, becomes readily apparent at low temperatures, representing a fingerprint of hot-carrier dominated thermoelectricity. By studying VNL as a function of bias, we directly determine the carrier temperature and the characteristic cooling length for hot-carrier propagation, which are key parameters for a variety of new applications that rely on hot-carrier transport. PMID:25950746

  8. Method of remote powering and detecting multiple UWB passive tags in an RFID system

    Energy Technology Data Exchange (ETDEWEB)

    Dowla, Farid U. (Castro Valley, CA); Nekoogar, Faranak (San Ramon, CA); Benzel, David M. (Livermore, CA); Dallum, Gregory E. (Livermore, CA); Spiridon, Alex (Palo Alto, CA)

    2012-05-29

    A new Radio Frequency Identification (RFID), tracking, powering apparatus/system and method using coded Ultra-wideband (UWB) signaling is introduced. The proposed hardware and techniques disclosed herein utilize a plurality of passive UWB transponders in a field of an RFID-radar system. The radar system itself enables multiple passive tags to be remotely powered (activated) at about the same time frame via predetermined frequency UWB pulsed formats. Once such tags are in an activated state, an UWB radar transmits specific "interrogating codes" to put predetermined tags in an awakened status. Such predetermined tags can then communicate by a unique "response code" so as to be detected by an UWB system using radar methods.

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

    OpenAIRE

    Dr K Thanushkodi, Y. Baby Kalpana

    2012-01-01

    Land Use is clearly constrained by environmental factors like soil characteristics, climatic conditions, water sources and vegetation. Changes in Land Use and Land Cover is a dynamic process taking place on the earth surface, and the spatial distribution of the changes that have taken place over a period of time and space is of immense importance in many natural studies. Whether regional or local in scope, remote sensing offers a means of acquiring and presenting land cover data in timely man...

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

    Directory of Open Access Journals (Sweden)

    D Shahbazi Gahrouei

    2005-09-01

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Jerry Myers

    2003-05-13

    Ophir Corporation was awarded a contract by the U. S. Department of Energy, National Energy Technology Laboratory under the Project Title ''Airborne, Optical Remote Sensing of Methane and Ethane for Natural Gas Pipeline Leak Detection'' on October 14, 2002. This six-month technical report summarizes the progress for each of the proposed tasks, discusses project concerns, and outlines near-term goals. Ophir has completed a data survey of two major natural gas pipeline companies on the design requirements for an airborne, optical remote sensor. The results of this survey are disclosed in this report. A substantial amount of time was spent on modeling the expected optical signal at the receiver at different absorption wavelengths, and determining the impact of noise sources such as solar background, signal shot noise, and electronic noise on methane and ethane gas detection. Based upon the signal to noise modeling and industry input, Ophir finalized the design requirements for the airborne sensor, and released the critical sensor light source design requirements to qualified vendors. Responses from the vendors indicated that the light source was not commercially available, and will require a research and development effort to produce. Three vendors have responded positively with proposed design solutions. Ophir has decided to conduct short path optical laboratory experiments to verify the existence of methane and absorption at the specified wavelength, prior to proceeding with the light source selection. Techniques to eliminate common mode noise were also evaluated during the laboratory tests. Finally, Ophir has included a summary of the potential concerns for project success and has established future goals.

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

    Directory of Open Access Journals (Sweden)

    Ana Vila-Concejo

    2012-12-01

    Full Text Available An investigation into the evolution of coral rubble deposits on a coral reef platform is assessed using high-resolution remote sensing data and geospatial analysis. Digital change detection analysis techniques are applied to One Tree Reef in the southern Great Barrier Reef by analysing aerial photographs and satellite images captured between 1964 and 2009. Two main types of rubble deposits were identified: (1 rubble flats that are featureless mass accumulations of coral rubble; and, (2 rubble spits that are shore-normal linear features. While both deposits prograde in a lagoon-ward direction, rubble spits move faster (~2 m/yr than rubble flats (~0.5 m/yr. The volume of rubble, the underlying substrate, the energy regime, and storm frequency control the rate of progradation. Rubble flat occurrence is restricted to the high-energy (windward margin of the coral reef platform, while rubble spits are distributed reef wide, both in modal high energy and modal low energy regions of the reef. Rubble spit deposition is considered to be a result of enlarged spur and groove morphology of the forereef, whereby wave energy is focused through the enlarged groove formations causing the preferential deposition of coral rubble in particular zones of the adjacent reef flat. One last control is thought to be the elevation of the reef crest whereby lower areas are more prone to rubble flat development. A vertical and ocean-ward accumulation of rubble is occurring on the windward margin of the reef leading to a build-up and build-out of the reef, governing the expansion of the reef footprint. This study shows for the first time the evolution of a coral reef rubble flat and rubble spits over decadal time scales as detected through remotely sensed images spanning 45 years.

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

    Directory of Open Access Journals (Sweden)

    V.PADMAJA, KAVITHA MAMINDLA

    2013-11-01

    Full Text Available In this paper the Detection of Moving obstacle and remote video monitoring and extracting the key frames from the captured video system based on high performance SAMSUNG S5PV210 CORTEX-A8 processor core is build and expanding peripheral devices using embedded Linux as the operating system. Today monitoring systems are either webcam based or simple motion detection based. Here we have interfaced both webcam and PIR sensor to the embedded system so that the user can get an immediate alert message and can take necessary steps. This system is based on the kernel of Cortex board with the GSM module being triggered by a Pyroelectric Infrared Sensor (PIR, which senses changes in the external temperature, especially in this case when an invader enters in to remote location and send SMS to the user. At the same time, by using a smart device or a PC, the user can link to the video streaming server constructed on the embedded board via the internet and browse the webpage to monitor the surveillance area, here the UVC driver and V4L programming is used to interface USB camera to the board to capture video information and then board will do two parallel works first one is transmits the processed captured video information using wireless network, which will be collected and monitored at client side using wireless network connection through the wireless device, second one is extracts the key frames from captured video using OpenCV and served on a server, the both provides an advantage to surveillance monitoring system.

  14. Detection, Identification, Location, and Remote Sensing using SAW RFID Sensor Tags

    Science.gov (United States)

    Barton, Richard J.

    2009-01-01

    In this presentation, we will consider the problem of simultaneous detection, identification, location estimation, and remote sensing for multiple objects. In particular, we will describe the design and testing of a wireless system capable of simultaneously detecting the presence of multiple objects, identifying each object, and acquiring both a low-resolution estimate of location and a high-resolution estimate of temperature for each object based on wireless interrogation of passive surface acoustic wave (SAW) radiofrequency identification (RFID) sensor tags affixed to each object. The system is being studied for application on the lunar surface as well as for terrestrial remote sensing applications such as pre-launch monitoring and testing of spacecraft on the launch pad and monitoring of test facilities. The system utilizes a digitally beam-formed planar receiving antenna array to extend range and provide direction-of-arrival information coupled with an approximate maximum-likelihood signal processing algorithm to provide near-optimal estimation of both range and temperature. The system is capable of forming a large number of beams within the field of view and resolving the information from several tags within each beam. The combination of both spatial and waveform discrimination provides the capability to track and monitor telemetry from a large number of objects appearing simultaneously within the field of view of the receiving array. In the presentation, we will summarize the system design and illustrate several aspects of the operational characteristics and signal structure. We will examine the theoretical performance characteristics of the system and compare the theoretical results with results obtained from experiments in both controlled laboratory environments and in the field.

  15. Embedded DSP-based telehealth radar system for remote in-door fall detection.

    Science.gov (United States)

    Garripoli, Carmine; Mercuri, Marco; Karsmakers, Peter; Jack Soh, Ping; Crupi, Giovanni; Vandenbosch, Guy A E; Pace, Calogero; Leroux, Paul; Schreurs, Dominique

    2015-01-01

    Telehealth systems and applications are extensively investigated nowadays to enhance the quality-of-care and, in particular, to detect emergency situations and to monitor the well-being of elderly people, allowing them to stay at home independently as long as possible. In this paper, an embedded telehealth system for continuous, automatic, and remote monitoring of real-time fall emergencies is presented and discussed. The system, consisting of a radar sensor and base station, represents a cost-effective and efficient healthcare solution. The implementation of the fall detection data processing technique, based on the least-square support vector machines, through a digital signal processor and the management of the communication between radar sensor and base station are detailed. Experimental tests, for a total of 65 mimicked fall incidents, recorded with 16 human subjects (14 men and two women) that have been monitored for 320 min, have been used to validate the proposed system under real circumstances. The subjects' weight is between 55 and 90 kg with heights between 1.65 and 1.82 m, while their age is between 25 and 39 years. The experimental results have shown a sensitivity to detect the fall events in real time of 100% without reporting false positives. The tests have been performed in an area where the radar's operation was not limited by practical situations, namely, signal power, coverage of the antennas, and presence of obstacles between the subject and the antennas. PMID:25291803

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

    DEFF Research Database (Denmark)

    KiØrboe, Thomas; Thygesen, Uffe HØgsbro

    2001-01-01

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

  17. Land cover changed object detection in remote sensing data with medium spatial resolution

    Science.gov (United States)

    Yang, Xiao tong; Liu, Huiping; Gao, Xiaofeng

    2015-06-01

    Land cover change information is crucial to analyse the process and the change patterns of environments and ecological systems. Recent studies have incorporated object-based image analysis for its ability to generate meaningful geographical objects into studies of change detection. In this research, we developed a systematic methodology to realise multi-type land cover changed object detection with medium spatial resolution remote sensing images in Beijing, China. Optimum index factor (OIF) was applied to determine the best change indicators and the chi-square transformation was carried out to determine the change threshold of the 4 classes of changed object. The clustering change vectors in the feature space were proposed to discriminate the change types. According to the accuracy assessment, the overall accuracy of changed/unchanged object detection was approximately 93.9% with an overall kappa of 0.824, and the change type discrimination also achieved an overall accuracy of 81.67%, indicating the effectiveness of the proposed method.

  18. Image processing and classification for the UK remote minefield detection system infrared polarimetric camera

    Science.gov (United States)

    Williams, John W.; Tee, Howard S.; Poulter, Mark A.

    2001-10-01

    The UK Remote Minefield Detection System (REMIDS) Technology Demonstration Programme (TDP) aims to demonstrate the applicability of emerging technologies in an integrated system for detecting mined areas from an airborne platform. The multi-sensor demonstrator is being managed by DERA on behalf of the UK MoD with an unmanned air vehicle (UAV) as the intended platform. The TDP is nearing the end of a five year programme that has developed a novel ultra wide band synthetic aperture radar (UWB SAR) and a MWIR time-parallel polarimetric IR camera (IRPC). A ground station processor has also been developed to fuse sensor outputs through a variety of detection and identification algorithms. An extensive series of data collection trials and analysis activities has been performed. This paper reports on the development by DERA of the algorithms required both to pre- process raw data from the IRPC into a useable form, and to discriminate mines from a variety of backgrounds. These algorithms are being integrated into ground station processing that will combine data from both sensors to identify mine areas and accurately delineate their boundaries. The top-level process architecture for this ground station, and how the IPRC fits within it, are also described in this paper.

  19. Remote listening and passive acoustic detection in a 3-D environment

    Science.gov (United States)

    Barnhill, Colin

    Teleconferencing environments are a necessity in business, education and personal communication. They allow for the communication of information to remote locations without the need for travel and the necessary time and expense required for that travel. Visual information can be communicated using cameras and monitors. The advantage of visual communication is that an image can capture multiple objects and convey them, using a monitor, to a large group of people regardless of the receiver's location. This is not the case for audio. Currently, most experimental teleconferencing systems' audio is based on stereo recording and reproduction techniques. The problem with this solution is that it is only effective for one or two receivers. To accurately capture a sound environment consisting of multiple sources and to recreate that for a group of people is an unsolved problem. This work will focus on new methods of multiple source 3-D environment sound capture and applications using these captured environments. Using spherical microphone arrays, it is now possible to capture a true 3-D environment A spherical harmonic transform on the array's surface allows us to determine the basis functions (spherical harmonics) for all spherical wave solutions (up to a fixed order). This spherical harmonic decomposition (SHD) allows us to not only look at the time and frequency characteristics of an audio signal but also the spatial characteristics of an audio signal. In this way, a spherical harmonic transform is analogous to a Fourier transform in that a Fourier transform transforms a signal into the frequency domain and a spherical harmonic transform transforms a signal into the spatial domain. The SHD also decouples the input signals from the microphone locations. Using the SHD of a soundfield, new algorithms are available for remote listening, acoustic detection, and signal enhancement The new algorithms presented in this paper show distinct advantages over previous detection and listening algorithms especially for multiple speech sources and room environments. The algorithms use high order (spherical harmonic) beamforming and power signal characteristics for source localization and signal enhancement These methods are applied to remote listening, surveillance, and teleconferencing.

  20. Transient detection of early wallerian degeneration on diffusion-weighted MRI after an acute cerebrovascular accident

    Energy Technology Data Exchange (ETDEWEB)

    Uchino, A.; Sawada, A.; Takase, Y.; Egashira, R.; Kudo, S. [Department of Radiology, Saga Medical School, 5-1-1 Nabeshima, Saga, 849-8501 (Japan)

    2004-03-01

    We report three patients with a cerebrovascular accident studied serially by MRI, including diffusion-weighted imaging (DWI). In case 1, DWI 1 day after the onset of left frontoparietal cortical infarcts showed no abnormal signal in the left corticospinal tract. DWI 12 days after onset showed high signal in the corticospinal tract, interpreted as early wallerian degeneration. This had disappeared by 22 days after onset. In case 2, DWI obtained 7 days after the onset of a right internal capsule lacunar infarct showed high signal from the right corticospinal tract in the brainstem, which was less marked 15 days after onset. In case 3, MRI on postnatal day 7 showed a cerebral haemorrhage in the right corona radiata and high signal from the right corticospinal tract on DWI. The latter disappeared by day 23. DWI shows early wallerian degeneration; transient signal abnormalities within 2 weeks of stroke should not be mistaken for new ischaemic lesions. (orig.)

  1. Retospective audit to determine the diagnostic accuracy of Primovist-enhanced MRI in the detection of hepatocellular carcinoma in cirrhosis with explant histopathology correlation

    International Nuclear Information System (INIS)

    This study aims to determine the diagnostic accuracy of Primovist-enhanced MRI in the detection of hepatocellular carcinoma (HCC) in cirrhosis, using liver explant histopathology correlation. Thirty patients underwent a Primovist-enhanced MRI prior to liver transplantation for cirrhosis at the Princess Alexandra Hospital from 2006 to June 2012. Pre-contrast T1, T2 and post-Primovist arterial, portal venous and delayed hepatobiliary phase sequences were routinely obtained. A retrospective audit of MRI reports determined whether HCCs was identified on pre-transplantation imaging. Results were correlated to the explant liver histopathology. Specificity and sensitivity of Primovist in HCC identification in cirrhosis was determined. The time interval between preoperative MRI and transplantation ranged from the day of transplantation to 112 weeks pre-transplantation. Thirty-nine HCCs were identified histologically in explants. Fifteen HCCs were identified on pre-transplant MRI in 11 patients, ranging from 11 to 43mm, all confirmed on histopathology. Fourteen MRI studies identified no lesion, concordant on histology. Twenty-four either well or moderately differentiated HCCs were identified on histopathology, all of which were less than 17mm, were not depicted on MRI. No poorly differentiated HCCs were present in the explants. Two regenerative nodules were correctly identified on MRI. This correlated to a sensitivity of 42.5%, specificity of 100% and a positive predictive value of 100% and negative predictive value of 39.5%. Primovist-enhanced MRI is very accurate in the identification of HCC in cirrhosis, especially if the tumour is greater than 17mm and undifferentiated. However, sensitivity is reduced for well- and moderately differentiated HCC less than 17mm.

  2. Multidimensional nos supervised analysis (textural and spacial) in MRI tomography for watercore detection

    OpenAIRE

    Melado, A.; Barreiro, P; Ruíz-Cabello, J.; Fernández-Valle, M. E.; Blanco Braña, Álvaro; Val Falcón, Jesús

    2010-01-01

    This work has been 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 combination and application of different non-destructive techniques such as X-ray CT, OCT, MRI, NMR, TRS and SRS, aimed at online sensing of food microstructure, water status, texture and optical pr...

  3. Accuracy of abdominal ultrasound and MRI for detection of Crohn disease and ulcerative colitis in children

    Energy Technology Data Exchange (ETDEWEB)

    Ziech, Manon L.W.; Smets, Anne M.J.B.; Lavini, Cristina; Caan, Matthan W.A.; Nederveen, Aart J.; Bipat, Shandra; Stoker, Jaap [Academic Medical Center, Department of Radiology, Amsterdam (Netherlands); Hummel, Thalia Z.; Benninga, Marc A.; Kindermann, Angelika [Emma Children' s Hospital, Academic Medical Center, Department of Pediatric Gastroenterology, Amsterdam (Netherlands); Nievelstein, Rutger A.J. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Roelofs, Joris J.T.H. [Academic Medical Center, Department of Pathology, Amsterdam (Netherlands)

    2014-11-15

    Endoscopy is currently the primary diagnostic technique for inflammatory bowel disease (IBD) in children. To assess the accuracy of US and dynamic contrast-enhanced MRI for diagnosing inflammatory bowel disease and for distinguishing Crohn disease and ulcerative colitis in comparison to a reference standard. Consecutive children with suspected IBD underwent diagnostic workup including ileocolonoscopy and upper gastrointestinal endoscopy as the reference standard, abdominal US, and MR enterography and colonography at 3 T. The protocol included a dynamic contrast-enhanced 3-D sequence. Sensitivity, specificity and kappa values were calculated for one ultrasonographer and two MRI observers. We included 28 children (15 boys) with mean age 14 years (range 10-17 years). The diagnosis was IBD in 23 children (72%), including 12 with Crohn disease, 10 with ulcerative colitis and 1 with indeterminate colitis. For the diagnosis of inflammatory bowel disease the sensitivity was 55% for US and 57% (both observers) for MR entero- and colonography, and the specificity was 100% for US and 100% (observer 1) and 75% (observer 2) for MR entero- and colonography. Combined MRI and US had sensitivity and specificity of 70% and 100% (observer 1) and 74% and 80% (observer 2), respectively. With the addition of a dynamic contrast-enhanced MR sequence, the sensitivity increased to 83% and 87%. US and MRI could only distinguish between Crohn disease and ulcerative colitis when terminal ileum lesions were present. US and MR entero- and colonography have a high accuracy for diagnosing inflammatory bowel disease in children but cannot be used to distinguish Crohn disease and ulcerative colitis. (orig.)

  4. Advances in MRI-Based Detection of Cerebrovascular Changes after Experimental Traumatic Brain Injury

    OpenAIRE

    Dijkhuizen, Rick M.

    2011-01-01

    Traumatic brain injury is a heterogeneous and multifaceted neurological disorder that involves diverse pathophysiological pathways and mechanisms. Thorough characterization and monitoring of the brain’s status after neurotrauma is therefore highly complicated. Magnetic resonance imaging (MRI) provides a versatile tool for in vivo spatiotemporal assessment of various aspects of central nervous system injury, such as edema formation, perfusion disturbances and structural tissue damage. Moreov...

  5. Accuracy of abdominal ultrasound and MRI for detection of Crohn disease and ulcerative colitis in children

    International Nuclear Information System (INIS)

    Endoscopy is currently the primary diagnostic technique for inflammatory bowel disease (IBD) in children. To assess the accuracy of US and dynamic contrast-enhanced MRI for diagnosing inflammatory bowel disease and for distinguishing Crohn disease and ulcerative colitis in comparison to a reference standard. Consecutive children with suspected IBD underwent diagnostic workup including ileocolonoscopy and upper gastrointestinal endoscopy as the reference standard, abdominal US, and MR enterography and colonography at 3 T. The protocol included a dynamic contrast-enhanced 3-D sequence. Sensitivity, specificity and kappa values were calculated for one ultrasonographer and two MRI observers. We included 28 children (15 boys) with mean age 14 years (range 10-17 years). The diagnosis was IBD in 23 children (72%), including 12 with Crohn disease, 10 with ulcerative colitis and 1 with indeterminate colitis. For the diagnosis of inflammatory bowel disease the sensitivity was 55% for US and 57% (both observers) for MR entero- and colonography, and the specificity was 100% for US and 100% (observer 1) and 75% (observer 2) for MR entero- and colonography. Combined MRI and US had sensitivity and specificity of 70% and 100% (observer 1) and 74% and 80% (observer 2), respectively. With the addition of a dynamic contrast-enhanced MR sequence, the sensitivity increased to 83% and 87%. US and MRI could only distinguish between Crohn disease and ulcerative colitis when terminal ileum lesions were present. US and MR entero- and colonography have a high accuracy for diagnosing inflammatory bowel disease in children but cannot be used to distinguish Crohn disease and ulcerative colitis. (orig.)

  6. MRI of prostate cancer using three different coil systems: image quality, tumor detection, and staging

    International Nuclear Information System (INIS)

    Purpose: To compare three MRI coil systems in terms of image quality, delineation of prostate cancer, and tumor staging. Materials and Methods: 49 patients with prostate cancer underwent MRI at 1.5 Tesla using a combination of an endorectal coil with a phased-array body coil (combination coil) prior to radical prostatectomy. Images were reconstructed from the data sets acquired with the endorectal coil alone and from those acquired with the combined coil. In addition, 19 patients of the study patients were examined with the body phased-array coil alone without the endorectal coil. The prostate was imaged at a slice thickness of 3 mm using axial and coronal T2-weighted sequences and an axial T1-weighted sequence. Preoperative analysis of all images acquired was done to determine the accuracy of MRI in local staging of prostate cancer. An additional retrospective analysis served to compare the different coil systems in terms of overall image quality, delineation and localization of the tumor, and criteria for local staging of prostate cancer. Results: Preoperative analysis showed MRI to have an accuracy of 59% in local tumor staging. Retrospective coil-by-coil analysis demonstrated image quality and tumor delineation to be best for the combination coil and the endorectal coil. Regarding the staging criteria for transcapsular tumor extension and infiltration of adjacent organs, a significant advantage of the combination coil compared to the endorect combination coil compared to the endorectal coil was identified only for the criterion of smooth bulging. In addition, the endorectal coil and the combination coil were found to be superior to the body phased-array coil in assessing 15 of 17 criteria for local tumor staging but the differences were not significant. Conclusion: In view of the achieved superior image quality, the combination coil or the endorectal coil is the preferred method for staging prostate cancer. (orig.)

  7. Vascular Differences Detected by MRI for Metastatic Versus Nonmetastatic Breast and Prostate Cancer Xenografts

    Directory of Open Access Journals (Sweden)

    Zaver M. Bhujwalla

    2001-01-01

    Full Text Available Several studies have linked vascular density, identified in histologic sections, to “metastatic risk.” Functional information of the vasculature, not readily available from histologic sections, can be obtained with contrast-enhanced MRI to exploit for therapy or metastasis prevention. Our aims were to determine if human breast and prostate cancer xenograffs preselected for differences in invasive and metastatic characteristics established correspondingly different vascular volume and permeability, quantified here with noninvasive MRI of the intravascular contrast agent albumin-GdDTPA. Tumor vascular volume and permeability of human breast and prostate cancer xenografts were characterized using MRI. Parallel studies confirmed the invasive behavior of these cell lines. Vascular endothelial growth factor (VEGF expression in the cell lines was measured using ELISA and Western blots. Metastasis to the lungs was evaluated with spontaneous as well as experimental assay. Metastatic tumors formed vasculature with significantly higher permeability or vascular volume (P < .05, two-sided unpaired t test. The permeability profile matched VEGF expression. Within tumors, regions of high vascular volume usually exhibited low permeability whereas regions of low vascular volume exhibited high permeability. We observed that although invasion was necessary, without adequate vascularization it was not sufficient for metastasis to occur.

  8. ROLE OF MULTIPARAMETRIC MRI IN THE DETECTION AND LOCALIZATION OF EARLY-STAGE PROSTATE CANCER

    Directory of Open Access Journals (Sweden)

    G. I. Akhverdieva

    2014-07-01

    Full Text Available The efficiency of prostate cancer (PC diagnosis using multipatametric magnetic resonance imaging (MRI was evaluated. Unlike most of investigations of the similar problem, this trial provides an objective assessment applying the method of statistical analysis - binary logistic regression. It used data on 166 patients, including primary patients (with suspected PC, as well as patients with the established diagnosis of PC, those with a history of negative biopsy, and those with suspected recurrent PC. Some patients underwent target biopsy, the results of which were then employed for statistical processing. The data of the analysis showed that the sensitivity, specificity, and total accuracy of the method using the created model of binary logistic regression at the separation value of 0.625 were 75.0, 85.2, and 79.7%, respectively. The efficiency of diffusion-weighted images (DWI with varying weighing degree by water molecule diffusion (b factor on MRI systems with different magnetic field strength (1.5 and 3 Tesla was also evaluated. There were no statistically significant differences in normalized absolute signal intensity as to the contralateral gland portion in DWI with b factors of 1000 and 2000 between the MRI systems with a magnetic field strength of 1.5 and 3.0 Tesla.

  9. 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 MRI-detected breast lesions. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.)

  11. 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.)

  12. Detection of contralateral normal ovary in patients with large(>10 cm) unilateral ovarian mass by using MRI

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Young Jin; Cho, Jae Ho; Park, Won Kyu [School of Medicine, Yeungnam Univ., Daegu (Korea, Republic of); Kim, Jae Woon [Youngshin Hospital, Seoul (Korea, Republic of)

    2004-02-01

    To assess the usefulness of MRI for determining the presence of a large (> 10 cm) unilateral ovarian tumor by detecting the existence of a normal contralateral ovary, and to establish the difference in detection rates between premenopausal and postmenopausal women, and benign and malignant tumors. Forty-two patients who underwent MR imaging and in whom the intraoperative gross and pathologic findings indicated the presence of a unilateral ovarian mass and a normal contralateral ovary were included in this study. The images obtained were retrospectively analyzed by two radiologists, who determined the detection rate of the normal contralateral ovary and whether this differed between premenopausal and postmenopausal women, and benign and malignant tumors. Contralateral normal ovaries were detected in 35 (83.3%) of 42 patients [22 of 23 ovaries (95.7%) in premenopausal women and 13 of 19 (68.4%) in postmenopausal women], with a statistically significant difference (p=0.018). Twelve of 16 of these ovaries (75%) were present in women with malignant tumors, and 23 (88.5%) of 26 in those with benign tumors, but the difference was not statistically significant (p=0.256). MR imaging is useful for detecting a normal contralateral ovary and for determining the site at which a large (> 10 cm) unilateral ovarian tumor originates, especially in premenopausal women.

  13. Rejection of crosstalk and noise by a quasi balanced CFPI for remote ultrasound detection

    International Nuclear Information System (INIS)

    In this paper we show the benefits of a quasi balanced fringe hopping CFPI (confocal Fabry-Perot interferometer) with broadband CMRR (common mode rejection ratio) for remote ultrasound detection. Ultrasonic information in general lies in the phase modulation of laser light which in this case is demodulated by using the CFPI at a certain working point on a fringe. By hopping from the positive to the negative slope on the same fringe the detected ultrasonic signals are inverted. In contrary interference signals like crosstalk from the generation, ghosts, or noise correlated to pulse laser excitation are not influenced and hence get rejected by subtracting the signals from both slopes. Hence, a minimum of two measurements is needed for common mode rejection. The fringe hopping from the positive to the negative slope is done by changing the distance of the CFPI mirrors with a precise piezoelectric-stack and a fast high resolution digital controller. As only one photo-detector with a transimpedance-amplifier is needed a high CMRR can be accomplished which is not affected by the symmetry of the fringe but only by pulse to pulse energy fluctuations of the generation laser. We show that with fringe hopping and averaging the signal to noise ratio increases much faster than with averaging without fringe hopping. This is due to the correlation of the quasi-noise with the generation cycle.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-09-01

    A new concept for radiation detection is proposed, allowing a decoupling of the sensing medium and the readout. An electromagnetic material, such as a magnetic ceramic ferrite, is placed near a source to be tracked such as a shipping container. The electromagnetic material changes its properties, in this case its magnetic permeability, as a function of radiation. This change is evident as a change in reflection frequency and magnitude when probed using a microwave/millimeter-wave source. This brief report discusses modeling of radiation interaction of various candidate materials using a radiation detector modeling code Geant4, system design considerations for the remote readout, and some theory of the material interaction physics. The theory of radiation change in doped magnetic insulator ferrites such as yttrium iron garnet (YIG) seems well founded based on literature documentation of the photomagnetic effect. The literature also suggests sensitivity of permittivity to neutrons in some ferroelectrics. Research to date indicates that experimental demonstration of these effects in the context of radiation detection is warranted.

  15. Remote Sensing of Mycorrhizae? Detection of Mycorrhizal Association from Canopy Spectral Properties.

    Science.gov (United States)

    Fisher, J. B.; Sweeney, S.; Brzostek, E. R.; Evans, T. P.; Bourg, N. A.; Phillips, R.

    2014-12-01

    Nearly all tree species form symbiotic relationships with one of two types of mycorrzhae—arbuscular mycorrhizae (AM) and ectomycorrhizal (ECM) fungi. AM- and ECM-dominated forests often have distinct nutrient economies, and there is strong interest in mapping or detecting mycorrhizae over large areas. We explored remotely sensed tree canopy spectral properties to "detect" underlying mycorrhizal association across a gradient of AM- and ECM-dominated forest plots. We used a combination of principal components analysis and statistical mining of reflectance and band differencing across moderate/high-resolution Landsat data in conjunction with phenological signals from stitched seasonal time series and topographic features. This approach was trained and validated against measurements of tree species and mycorrhizal association across more than 60,000 trees throughout the central and eastern US. Using this approach, we were able to predict 81% of the variation in mycorrhizal association (p<0.001). Differences in phenological characteristics between AM- and ECM-associated trees drove the relatively high prediction skill.

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

    DEFF Research Database (Denmark)

    Gliese, Ulrik Bo; Nielsen, Torben NØrskov

    1998-01-01

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

  17. Multiple change detection for multispectral remote sensing images via joint sparse representation

    Science.gov (United States)

    Song, Huihui; Wang, Guojie; Zhang, Kaihua

    2014-12-01

    We propose an approach for multiple change detection in multispectral remote sensing images based on joint sparse representation. The principal idea is that each change class lies in a low-dimensional space, in which the change vectors can be represented by a linear combination of a few representation atoms. Our method includes two stages: (1) in the learning stage, we learn a subdictionary for each change class from the training samples; and (2) in the reference stage, each change pixel vector is represented with respect to all subdictionaries and assigned to the class with minimum representation errors. Furthermore, taking into account the spatial contextual information, we propose a joint sparsity model to represent each pixel and its similar neighbors simultaneously, thereby enhancing the robustness of the representation to noise. To validate the effectiveness of the proposed method, we choose Shenzhen, China, as the study area in the context of fast urban growth. During the experiments, the proposed method achieves better results on two Landsat Enhanced Thematic Mapper Plus images than does another state-of-the-art supervised change-detection method.

  18. Multisensor remote sensing information fusion for urban area classification and change detection

    Science.gov (United States)

    Palubinskas, Gintautas; Makarau, Aliaksei; Reinartz, Peter

    2011-05-01

    Information extraction from multi-sensor remote sensing imagery is an important and challenging task for many applications such as urban area mapping and change detection. A special acquisition (orthogonal) geometry is of great importance for optical and radar data fusion. This acquisition geometry allows to minimize displacement effects due inaccuracy of Digital Elevation Model (DEM) used for data ortho-rectification and existence of unknown 3D structures in a scene. Final data spatial alignment is performed by recently proposed co-registration method based on a Mutual Information measure. For a combination of features originating from different sources, which are quite often noncommensurable, we propose an information fusion framework called INFOFUSE consisting of three main processing steps: feature fission (feature extraction aiming at complete description of a scene), unsupervised clustering (complexity reduction and feature representation in a common dictionary) and supervised classification realized by Bayesian or Neural networks. An example of urban area classification is presented for the orthogonal acquisition of space borne very high resolution WorldView-2 and TerraSAR-X Spotlight imagery over Munich city, South Germany. Experimental results confirm our approach and show a great potential also for other applications such as change detection.

  19. Remote detection of magmatic water in Bullialdus crater on the Moon

    Science.gov (United States)

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

    2013-01-01

    Once considered dry compared with Earth, laboratory analyses of igneous components of lunar samples have suggested that the Moon’s interior is not entirely anhydrous. Water and hydroxyl have also been detected from orbit on the lunar surface, but these have been attributed to nonindigenous sources, such as interactions with the solar wind. Magmatic lunar volatiles—evidence for water indigenous to the lunar interior—have not previously been detected remotely. Here we analyse spectroscopic data from the Moon Mineralogy Mapper (M3) and report that the central peak of Bullialdus Crater is significantly enhanced in hydroxyl relative to its surroundings. We suggest that the strong and localized hydroxyl absorption features are inconsistent with a surficial origin. Instead, they are consistent with hydroxyl bound to magmatic minerals that were excavated from depth by the impact that formed Bullialdus Crater. Furthermore, estimates of thorium concentration in the central peak using data from the Lunar Prospector orbiter indicate an enhancement in incompatible elements, in contrast to the compositions of water-bearing lunar samples. We suggest that the hydroxyl-bearing material was excavated from a magmatic source that is distinct from that of samples analysed thus far.

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

    Science.gov (United States)

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

    2009-04-01

    The paper presents elements of research conducted in the Faculty of Civil Engineering and Geodesy of the Military University of Technology, Warsaw, Poland, concerning application of mesoscale models and remote sensing data to determining meteorological conditions of aircraft flight directly related with atmospheric instabilities. The quality of meteorological support of aviation depends on prompt and effective forecasting of weather conditions changes. The paper presents a computer module for detecting and monitoring zones of cloud cover, precipitation and turbulence along the aircraft flight route. It consists of programs and scripts for managing, processing and visualizing meteorological and remote sensing databases. The application was developed in Matlab® for Windows®. The module uses products of COAMPS (Coupled Ocean/Atmosphere Mesoscale Prediction System) mesoscale non-hydrostatic model of the atmosphere developed by the US Naval Research Laboratory, satellite images acquisition system from the MSG-2 (Meteosat Second Generation) of the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT) and meteorological radars data acquired from the Institute of Meteorology and Water Management (IMGW), Warsaw, Poland. The satellite images acquisition system and the COAMPS model are run operationally in the Faculty of Civil Engineering and Geodesy. The mesoscale model is run on an IA64 Feniks multiprocessor 64-bit computer cluster. The basic task of the module is to enable a complex analysis of data sets of miscellaneous information structure and to verify COAMPS results using satellite and radar data. The research is conducted using uniform cartographic projection of all elements of the database. Satellite and radar images are transformed into the Lambert Conformal projection of COAMPS. This facilitates simultaneous interpretation and supports decision making process for safe execution of flights. Forecasts are based on horizontal distributions and vertical profiles of meteorological parameters produced by the module. Verification of forecasts includes research of spatial and temporal correlations of structures generated by the model, e.g.: cloudiness, meteorological phenomena (fogs, precipitation, turbulence) and structures identified on current satellite images. The developed module determines meteorological parameters fields for vertical profiles of the atmosphere. Interpolation procedures run at user selected standard (pressure) or height levels of the model enable to determine weather conditions along any route of aircraft. Basic parameters of the procedures determining e.g. flight safety include: cloud base, visibility, cloud cover, turbulence coefficient, icing and precipitation intensity. Determining icing and turbulence characteristics is based on standard and new methods (from other mesoscale models). The research includes also investigating new generation mesoscale models, especially remote sensing data assimilation. This is required by necessity to develop and introduce objective methods of forecasting weather conditions. Current research in the Faculty of Civil Engineering and Geodesy concerns validation of the mesoscale module performance.

  1. Impact of functional MRI data preprocessing pipeline on default-mode network detectability in patients with disorders of consciousness

    Directory of Open Access Journals (Sweden)

    LudovicoMinati

    2013-08-01

    Full Text Available An emerging application of resting-state functional MRI is the study of patients with disorders of consciousness (DoC, where integrity of default-mode network (DMN activity is associated to the clinical level of preservation of consciousness. Due to the inherent inability to follow verbal instructions, arousal induced by scanning noise and postural pain, these patients tend to exhibit substantial levels of movement. This results in spurious, non-neural fluctuations of the blood-oxygen level-dependent (BOLD signal, which impair the evaluation of residual functional connectivity. Here, the effect of data preprocessing choices on the detectability of the DMN was systematically evaluated in a representative cohort of 30 clinically and etiologically heterogeneous DoC patients and 33 healthy controls. Starting from a standard preprocessing pipeline, additional steps were gradually inserted, namely band-pass filtering, removal of co-variance with the movement vectors, removal of co-variance with the global brain parenchyma signal, rejection of realignment outlier volumes and ventricle masking. Both independent-component analysis (ICA and seed-based analysis (SBA were performed, and DMN detectability was assessed quantitatively as well as visually. The results of the present study strongly show that the detection of DMN activity in the sub-optimal fMRI series acquired on DoC patients is contingent on the use of adequate filtering steps. ICA and SBA are differently affected but give convergent findings for high-grade preprocessing. We propose that future studies in this area should adopt the described preprocessing procedures as a minimum standard to reduce the probability of wrongly inferring that DMN activity is absent.

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

    Directory of Open Access Journals (Sweden)

    M. J. Lato

    2012-09-01

    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.

  3. A CAD system based on multi-parametric analysis for cancer prostate detection on DCE-MRI

    Science.gov (United States)

    Mazzetti, Simone; De Luca, Massimo; Bracco, Christian; Vignati, Anna; Giannini, Valentina; Stasi, Michele; Russo, Filippo; Armando, Enrico; Agliozzo, Silvano; Regge, Daniele

    2011-03-01

    Computer-aided diagnosis (CAD) systems using dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) data may be developed to help localize prostate cancer and guide biopsy, avoiding random sampling of the whole gland. The purpose of this study is to present a DCE-MRI CAD system, which calculates the likelihood of malignancy in a given area of the prostate by combining model-based and model-free parameters. The dataset includes 10 patients with prostate cancer, with a total of 13 foci of adenocarcinoma. The post-processing is based on the following steps: testing of registration quality, noise filtering, and extracting the proposed features needed to the CAD. Parameters with the best performance in discriminating between normal and cancer regions are selected by computing the area under the ROC curve, and by evaluating the correlation between pairs of features. A 6-dimensional parameters vector is generated for each pixel and fed into a Bayesian classifier, in which the output is the probability of malignancy. The classification performance is estimated using the leave-one-out method. The resulting area under the ROC curve is 0.899 (95%CI:0.893-0.905); sensitivity and specificity are 82.4% and 82.1% respectively at the best cut-off point (0.352). Preliminary results show that the system is accurate in detecting areas of the gland that are involved by tumor. Further studies will be necessary to confirm these promising preliminary results.

  4. A fully Bayesian approach to the parcel-based detection-estimation of brain activity in fMRI

    Energy Technology Data Exchange (ETDEWEB)

    Makni, S. [Univ Oxford, John Radcliffe Hosp, Oxford Ctr Funct Magnet Resonance Imaging Brain, Oxford OX3 9DU (United Kingdom); Idier, J. [IRCCyN CNRS, Nantes (France); Vincent, T.; Ciuciu, P. [CEA, NeuroSpin, Gif Sur Yvette (France); Vincent, T.; Dehaene-Lambertz, G.; Ciuciu, P. [Inst Imagerie Neurofonctionnelle, IFR 49, Paris (France); Thirion, B. [INRIA Futurs, Orsay (France); Dehaene-Lambertz, G. [INSERM, NeuroSpin, U562, Gif Sur Yvette (France)

    2008-07-01

    Within-subject analysis in fMRI essentially addresses two problems, i. e., the detection of activated brain regions in response to an experimental task and the estimation of the underlying dynamics, also known as the characterisation of Hemodynamic response function (HRF). So far, both issues have been treated sequentially while it is known that the HRF model has a dramatic impact on the localisation of activations and that the HRF shape may vary from one region to another. In this paper, we conciliate both issues in a region-based joint detection-estimation framework that we develop in the Bayesian formalism. Instead of considering function basis to account for spatial variability, spatially adaptive General Linear Models are built upon region-based non-parametric estimation of brain dynamics. Regions are first identified as functionally homogeneous parcels in the mask of the grey matter using a specific procedure [Thirion, B., Flandin, G., Pinel, P., Roche, A., Ciuciu, P., Poline, J.B., August 2006. Dealing with the shortcomings of spatial normalization: Multi-subject parcellation of fMRI datasets. Hum. Brain Mapp. 27 (8), 678-693.]. Then, in each parcel, prior information is embedded to constrain this estimation. Detection is achieved by modelling activating, deactivating and non-activating voxels through mixture models within each parcel. From the posterior distribution, we infer upon the model parameters using Markov Chain Monte Carlo (MCMC) techniques. Bayesian model comparison allows us to emphasize on artificial datasets first that inhomogeneous gamma-Gaussian mixture models outperform Gaussian mixtures in terms of sensitivity/specificity trade-off and second that it is worthwhile modelling serial correlation through an AR(1) noise process at low signal-to-noise (SNR) ratio. Our approach is then validated on an fMRI experiment that studies habituation to auditory sentence repetition. This phenomenon is clearly recovered as well as the hierarchical temporal organisation of the superior temporal sulcus, which is directly derived from the parcel-based HRF estimates. (authors)

  5. Dynamic contrast-enhanced MRI for the detection of testicular ischemia in experimental induced testicular torsion of rabbits

    International Nuclear Information System (INIS)

    Objective: To evaluate the dynamic contrast-enhanced MRI (DCE-MRI) in detecting experimentally induced testicular ischemia. Methods: Thirty healthy male New Zealand rabbits were randomly assigned into 6 groups. There were 5 rabbits in each of the following experimental groups: (1) Normal control, (2) Sham-operated, (3) ischemia of 3 h group, (4) ischemia of 6 h group, (5) ischemia of 12 h group, (6) ischemia of 24 h group. In all experiment groups, the right testis served as the internal control while the left testis served as the experimental side. DCE-MRI for each animal lasts about 10 minutes. Signal enhanced ratios (SERs) of ROI for both sides of each group were calculated by a computer, and parameters of SERs of 30 s, 75 s, 120 s and maximal SER were used for statistical analysis. Time intensity curves (TICs) were made for two sides of each group via Excel 2003 software and classified into 4 types. Statistical analysis was performed to compare the differences of SERs between left and right testis by two independent Kolmogorov-Smirnov test. Results: In group 1 and 2, significant enhancement was observed on both testes of 10 rabbits. The enhancement decreased gradually with the elongation of ischemia in torsion groups. Three cases of type ? and 2 cases of type ? were observed in group 1, 5 cases of type ? in group two, 2 cases of type ? and 3 cases of type ? b in group three, 2 cases of type ? and 2 cases of type ? b in group four, 5 cases of type b in group five and 5 cases of type ? in group six were noticed in the left testes. And in TICs of right testes, all cases showed TICs of type ? except 2 cases of type ? a in group six. In four torsion groups, the values for SER75 of the left side were 0.084%, 0.076%, 0.164% and 0.065%, while the right side were 0.255%, 0.410%, 0.586% and 0.302% (P120 in group three, five and six were 0.221%, 0.158% and 0.059% for the left side, and 0.405%, 0.522% and 0.207% for the right side (P<0.05). The values for MSER in group three, five and six were 0.217%, 0.164% and 0.072% for the left side, and 0.405%, 0.586% and 0.302% for the right side (P <0.05). Conclusion: DCE-MRI technique may be useful in the diagnosis of testicular torsion, which shows potential in the clinical application. (authors)

  6. FDG PET or PET-CT versus MRI in detecting local residue or recurrence of nasopharyngeal carcinoma after radiotherapy: a meta-analysis

    International Nuclear Information System (INIS)

    Objective: To compare the value of 18F-labeled deoxyglucose (FDG) PET or PET-CT with MRI in detecting local residue or recurrence of nasopharyngeal carcinoma after radiotherapy, by performing a meta-analysis of relevant trials. Methods: A literature search was performed to English original articles about FDG PET or PET-CT and MRI in Medline, Embase and the Cochrane database from January 1995 to August 2009. The reference standard was histopathologic analysis and/or close clinical and imaging follow-up. Two reviewers searched articles and extracted data independently. Sensitivity, specificity,summary receiver operating characteristic curves (SROC), and the Q index for FDG PET or PET-CT and MRI were pooled, respectively. Results: Seventeen studies about FDG PET or PET-CT and 10 studies about MRI were included in this meta-analysis.The pooled sensitivity of FDG PET or PET-CT and MRI were 0.935(95% CI= 0.901 -0.964) and 0.792 (95% CI= 0.731 -0.844), separately. The pooled specificity were 0.924 (95 % CI= 0.898 - 0.945) and 0.787 (95 % GI= 0.746 - 0.825), separately.Area under SROC curves of PET-CT or PET (0.966) was significantly larger than that of MRI (0.852) (z =2.29, P < 0.05).The Q * index estimates for PET-CT or PET (0.914) were significantly higher than for MRI (0.783)(z=2.94, P<0.05). Conclusions: FDG-PET/PET-CT has higher accuracy than MRI in diagnosing local residue or recurrence of nasopharyngeal carcinoma after radiotherapy. (authors)ter radiotherapy. (authors)

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

    Science.gov (United States)

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

    2010-05-01

    In Mediterranean and mountainous areas, an increase of mortality in forest is observed after important drought events. In the context of climate changes, a study of the impact of drought stress on forest is necessary. In order to detect water stress over the whole forest at different periods of the year, we propose the use of a spatialisable indicator, easily measurable: crown surface temperature. As previous works were not conclusive concerning the potentiality of this indicator in forest (Duchemin, 1998a, 1998b, Pierce et al., 1990), we set up an experimentation to study the surface temperature evolution linked to the transpiration at tree scale, during the spring and summer periods on silver fir (Abies alba) forest of Mont Ventoux (south of France). At the same time, several thermal infrared images of the mountainside were acquired corresponding to different levels of transpiration. The signal of surface temperature is studying via the evolution of the difference between measured surface temperature and calculated surface temperature for a tree at maximum transpiration rate. At tree scale, there is a difference of 4 °C of amplitude in the signal of surface temperature between maximum and zero transpiration conditions. The difficulty resides in taking into account the influence of climatic conditions, source of variability in the signal uncorrelated with transpiration evolution. Indices of surface temperature, built to include this influence of climatic conditions, permit to reduce this variability. Another source of variability lies in the percentage of branches present in the area of measurement. Indeed branches have a thermal dynamic differing from the needles one and, considering comparison between trees, the percentage of branches varies. At the mountainside scale, contrasted areas in terms of surface temperature indices are observable. By comparing different dates, corresponding to different levels of drought, it is possible to locate areas with precocious water stress signal. The amplitude of the signal, between wet and dry conditions, is at an average of 3 °C. Thus, by analysing the temporal evolution of this signal, thermal infrared is an interesting tool to detect water stress and identify different levels of stress between forest areas. Duchemin B., D. Guyon, J.P. Lagouarde, 1998. Potential and limits of NOAA-AVHRR temporal composite data forr phenology and water stress monitoring of temperate forest ecosystems. International Journal of remote sensing, volume: 20, 5, p 23. Duchemin B., Lagouarde J.P., 1998. Apport des capteurs satellitaires à large champ pour l'estimation de variables de fonctionnement des écosystèmes forestiers tempérés. Thesis. p120. Pierce L. L., Running S.W., Riggs G.A., 1990. Remote detection of canopy water stress in coniferous forests unsing the NS001 Thematic Mapper Simulator and the Thermal Infrared Multispectral Scanner. Photogrammetric engineering and remote sensing, volume: 56, 1, p 8.

  8. GPU implementation of target and anomaly detection algorithms for remotely sensed hyperspectral image analysis

    Science.gov (United States)

    Paz, Abel; Plaza, Antonio

    2010-08-01

    Automatic target and anomaly detection are considered very important tasks for hyperspectral data exploitation. These techniques are now routinely applied in many application domains, including defence and intelligence, public safety, precision agriculture, geology, or forestry. Many of these applications require timely responses for swift decisions which depend upon high computing performance of algorithm analysis. However, with the recent explosion in the amount and dimensionality of hyperspectral imagery, this problem calls for the incorporation of parallel computing techniques. In the past, clusters of computers have offered an attractive solution for fast anomaly and target detection in hyperspectral data sets already transmitted to Earth. However, these systems are expensive and difficult to adapt to on-board data processing scenarios, in which low-weight and low-power integrated components are essential to reduce mission payload and obtain analysis results in (near) real-time, i.e., at the same time as the data is collected by the sensor. An exciting new development in the field of commodity computing is the emergence of commodity graphics processing units (GPUs), which can now bridge the gap towards on-board processing of remotely sensed hyperspectral data. In this paper, we describe several new GPU-based implementations of target and anomaly detection algorithms for hyperspectral data exploitation. The parallel algorithms are implemented on latest-generation Tesla C1060 GPU architectures, and quantitatively evaluated using hyperspectral data collected by NASA's AVIRIS system over the World Trade Center (WTC) in New York, five days after the terrorist attacks that collapsed the two main towers in the WTC complex.

  9. Remote Detection and Modeling of Abrupt and Gradual Tree Mortality in the Southwestern USA

    Science.gov (United States)

    Muss, J. D.; Xu, C.; McDowell, N. G.

    2014-12-01

    Current climate models predict a warming and drying trend that has a high probability of increasing the frequency and spatial extent of tree mortality events. Field surveys can be used to identify, date, and attribute a cause of mortality to specific trees, but monetary and time constraints prevent broad-scale surveys, which are necessary to establish regional or global trends in tree mortality. This is significant because widespread forest mortality will likely lead to radical changes in evapotranspiration and surface albedo, which could compound climate change. While understanding the causes and mechanisms of tree mortality events is crucial, it is equally important to be able to detect and monitor mortality and subsequent changes to the ecosystem at broad spatial- and temporal-scales. Over the past five years our ability to remotely detect abrupt forest mortality events has improved greatly, but gradual events—such as those caused by drought or certain types of insects—are still difficult to identify. Moreover, it is virtually impossible to quantify the amount of mortality that has occurred within a mixed pixel. We have developed a system that fuses climate and satellite-derived spectral data to identify both the date and the agent of forest mortality events. This system has been used with Landsat time series data to detect both abrupt and general trends in tree loss that have occurred during the past quarter-century in northern New Mexico. It has also been used with MODIS data to identify pixels with a high likelihood of drought-caused tree mortality in the Southwestern US. These candidate pixels were then fed to ED-FRT, a coupled forest dynamics-radiative transfer model, to generate estimates of drought-induced. We demonstrate a multi-scale approach that can produce results that will be instrumental in advancing our understanding of tree mortality-climate feedbacks, and improve our ability to predict what forests could look like in the future.

  10. Detection of Shoreline and Land Cover Changes around Rosetta Promontory, Egypt, Based on Remote Sensing Analysis

    Directory of Open Access Journals (Sweden)

    Ali Masria

    2015-03-01

    Full Text Available Rosetta Promontory, Egypt has been suffering from a continuous erosion problem. The dramatic retreatment was observed during the last century. It is basically due to the construction of Aswan High Dam in 1964, which reduced the flow and sediment discharges. In this paper, four Landsat images (two Thematic Mapper and two Enhanced Thematic Mapper covering the period from 1984 to 2014 were used. These Landsat images were radio-metrically and geometrically corrected, and then, multi-temporal post-classification analysis was performed to detect land cover changes, extracting shoreline positions to estimate shoreline change rates of the Nile delta coast around Rosetta Promontory. This method provides a viable means for examining long-term shoreline changes. Four categories, including seawater, developed (agriculture and urban, sabkhas (salt-flat, and undeveloped areas, were selected to evaluate their temporal changes by comparing the four selected images. Supervised classification technique was used with support vector machine algorithm to detect temporal changes. The overall accuracy assessment of this method ranged from 97% to 100%. In addition, the shoreline was extracted by applying two different techniques. The first method is based on a histogram threshold of Band 5, and the other uses the combination of histogram threshold of Band 5 and two band ratios (Band 2/Band 4 and Band 2/Band 5. For land cover change detection from 1984 to 2014, it was found that the developed area that increased by 9% although the land in the study area has been contracted by 1.6% due to coastal erosion. The shoreline retreat rate has decreased more than 70% from 1984 to 2014. Nevertheless, it still suffers from significant erosion with a maximum rate of 37 m/year. In comparison to ground survey and different remote sensing techniques, the established trend of shoreline change extracted using histogram threshold was found to be closely consistent with these studies rather than combining band ratio with histogram threshold.

  11. Remote sensing analysis for fault-zones detection in the Central Andean Plateau (Catamarca, Argentina)

    Science.gov (United States)

    Traforti, Anna; Massironi, Matteo; Zampieri, Dario; Carli, Cristian

    2015-04-01

    Remote sensing techniques have been extensively used to detect the structural framework of investigated areas, which includes lineaments, fault zones and fracture patterns. The identification of these features is fundamental in exploration geology, as it allows the definition of suitable sites for the exploitation of different resources (e.g. ore mineral, hydrocarbon, geothermal energy and groundwater). Remote sensing techniques, typically adopted in fault identification, have been applied to assess the geological and structural framework of the Laguna Blanca area (26°35'S-66°49'W). This area represents a sector of the south-central Andes localized in the Argentina region of Catamarca, along the south-eastern margin of the Puna plateau. The study area is characterized by a Precambrian low-grade metamorphic basement intruded by Ordovician granitoids. These rocks are unconformably covered by a volcano-sedimentary sequence of Miocene age, followed by volcanic and volcaniclastic rocks of Upper Miocene to Plio-Pleistocene age. All these units are cut by two systems of major faults, locally characterized by 15-20 m wide damage zones. The detection of main tectonic lineaments in the study area was firstly carried out by classical procedures: image sharpening of Landsat 7 ETM+ images, directional filters applied to ASTER images, medium resolution Digital Elevation Models analysis (SRTM and ASTER GDEM) and hill shades interpretation. In addition, a new approach in fault zone identification, based on multispectral satellite images classification, has been tested in the Laguna Blanca area and in other sectors of south-central Andes. In this perspective, several prominent fault zones affecting basement and granitoid rocks have been sampled. The collected fault gouge samples have been analyzed with a Field-Pro spectrophotometer mounted on a goniometer. We acquired bidirectional reflectance spectra, from 0.35?m to 2.5?m with 1nm spectral sampling, of the sampled fault rocks. Subsequently, two different Spectral Angle Mapper (SAM) classifications were applied to ASTER images: the first one based on fault rock spectral signatures resampled at the ASTER sensor resolution; the second one based on spectral signatures retrieved from specific Region of Interest (ROI), which were directly derived from the ASTER image on the analyzed fault zones. The SAM classification based on the spectral signatures of fault rocks gave outstanding results since it was able to classify the analyzed fault zone, both in terms of length and width. Moreover, in some specific cases, this SAM classification identified not only the sampled fault zone, but also other prominent neighboring faults cutting the same host rock. These results define the SAM supervised classification on ASTER images as a tool to identify prominent fault zones directly on the base of fault-rocks spectra.

  12. MRI angiography is superior to helical CT for detection of HCC prior to liver transplantation: an explant correlation.

    Science.gov (United States)

    Burrel, Marta; Llovet, Josep M; Ayuso, Carmen; Iglesias, Carmela; Sala, Margarita; Miquel, Rosa; Caralt, Teresa; Ayuso, Juan Ramon; Solé, Manel; Sanchez, Marcelo; Brú, Concepció; Bruix, Jordi

    2003-10-01

    Helical computerized tomography (CT) and magnetic resonance imaging (MRI) are used for staging of hepatocellular carcinoma (HCC) prior to curative treatments but underestimate tumor extension in 30% to 50% of cases when compared with pathologic explants. This study compares a new technology, MRI angiography (MRA), with triphasic helical CT in detection of HCC. Fifty cirrhotic patients, 29 with HCC, undergoing liver transplantation were analyzed. MRA was performed with a 3-D breath-hold fast spoiled gradient-echo sequence by using an effective section thickness of 2 to 2.5 mm. The gold standard was the pathologic examination (liver cut into 5-mm slices). One hundred twenty-seven lesions were identified at the explant: 76 HCC, 13 high-grade dysplastic nodules, 31 macroregenerative nodules, 7 hemangiomas. Diameter of the main HCC nodules was 29 +/- 14 mm and 11 +/- 7 mm for the 47 additional nodules. On a per nodule basis, sensitivity of MRA was superior to CT (58/76 [76%] vs. 43/70 [61%], respectively, P =.001). Sensitivity of MRA for detection of additional nodules decreased with size (>20 mm: 6/6 [100%]; 10-20 mm: 16/19 [84%]; CT for nodules 10 to 20 mm (84% vs. 47%, P =.016). Nonspecific hypervascular nodules >5 mm at MRA were HCC in two thirds of the cases. In conclusion, MRA has a high diagnostic accuracy for HCC > or =10 mm and is more sensitive than triphasic helical CT in nodules sized 10 to 20 mm. MRA is the optimal technique for HCC staging prior to curative therapies. PMID:14512891

  13. Implant detectibility of intervertebral disc spacers in post fusion MRI: evaluation of the MRI scan quality by using a scoring system - an in vitro study

    Energy Technology Data Exchange (ETDEWEB)

    Ernstberger, Thorsten; Schultz, Wolfgang [University of Goettingen, Department of Orthopaedic Surgery, Goettingen (Germany); Heidrich, Gabert; Grabbe, Eckhardt [Georg-August-University of Goettingen, Department of Diagnostic Radiology, Goettingen (Germany)

    2007-02-15

    Intervertebral spacers for anterior spine fusion are made of different materials, such as titanium and cobalt chromium alloys and carbon fiber-reinforced polymers. Implant-related susceptibility artifacts can decrease the quality of MRI scans. The aim of this cadaveric study was to demonstrate the extent that implant-related MRI artifacting affects the postfusion differentiation of determined regions of interest (ROIs). In six cadaveric porcine spines, we evaluated the postimplantation MRI scans of a titanium, cobalt-chromium and carbon spacer that differed in shape and surface qualities. A spacer made of human cortical bone was used as a control. A defined evaluation unit was divided into ROIs to characterize the spinal canal as well as the intervertebral disc space. Considering 15 different MRI sequences read independently by an interobserver-validated team of specialists the artifact-affected image quality of the median MRI slice was rated on a score of 0-3. A maximum score of 18 points (100%) for the determined ROIs was possible. Turbo spin echo sequences produced the best scores for all spacers and the control. Only the control achieved a score of 100%. For the determined ROI maximum scores for the cobalt-chromium, titanium and carbon spacers were 24%, 32% and 84%, respectively. By using favored T1 TSE sequences the carbon spacer showed a clear advantage in postfusion spinal imaging. Independent of artifact dimensions, the scoring system used allowed us to create an implant-related ranking of MRI scan quality in reference to the bone control. (orig.)

  14. Implant detectibility of intervertebral disc spacers in post fusion MRI: evaluation of the MRI scan quality by using a scoring system - an in vitro study

    International Nuclear Information System (INIS)

    Intervertebral spacers for anterior spine fusion are made of different materials, such as titanium and cobalt chromium alloys and carbon fiber-reinforced polymers. Implant-related susceptibility artifacts can decrease the quality of MRI scans. The aim of this cadaveric study was to demonstrate the extent that implant-related MRI artifacting affects the postfusion differentiation of determined regions of interest (ROIs). In six cadaveric porcine spines, we evaluated the postimplantation MRI scans of a titanium, cobalt-chromium and carbon spacer that differed in shape and surface qualities. A spacer made of human cortical bone was used as a control. A defined evaluation unit was divided into ROIs to characterize the spinal canal as well as the intervertebral disc space. Considering 15 different MRI sequences read independently by an interobserver-validated team of specialists the artifact-affected image quality of the median MRI slice was rated on a score of 0-3. A maximum score of 18 points (100%) for the determined ROIs was possible. Turbo spin echo sequences produced the best scores for all spacers and the control. Only the control achieved a score of 100%. For the determined ROI maximum scores for the cobalt-chromium, titanium and carbon spacers were 24%, 32% and 84%, respectively. By using favored T1 TSE sequences the carbon spacer showed a clear advantage in postfusion spinal imaging. Independent of artifact dimensions, the scoring system used allowed us to createe scoring system used allowed us to create an implant-related ranking of MRI scan quality in reference to the bone control. (orig.)

  15. SQUID-Detected MRI in the Limit of Zero Static Field

    Energy Technology Data Exchange (ETDEWEB)

    Kelso, Nathan Dean

    2009-12-14

    This thesis describes an implementation of the so-called"zero-field MRI" (ZFMRI) pulse sequence, which allows for imaging in an arbitrarily low B(0) field. The ZFMRI sequence created an effective unidirectional gradient field by using a train of pi pulses to average out the concomitant gradient components during encoding. The signals were acquired using a low-transition temperature dc Superconducting QUantum Interference Device (low-Tc dc SQUID) coupled to a first-order axial gradiometer. The experiments were carried out in a liquid helium dewar which was magnetically shielded with a single-layer mu-metal can around the outside and a superconducting Pb can contained within the helium space. We increased the filling factor of the custom-made, double-walled Pyrex insert by placing the liquid alcohol sample, at a temperature of approximately -50 degrees C, at the center of one loop of the superconducting gradiometer, which was immersed in the helium bath.

  16. DETECTION OF COASTAL GEOMORPHOLOGICAL CHANGES FOR EFFECTIVE COASTAL MANAGEMENT USING REMOTE SENSING & GIS

    Directory of Open Access Journals (Sweden)

    SS.Asadi

    2015-02-01

    Full Text Available The present study deals with the Geomorphological changes Detection study in Pulicat Lagoon. The study involves identifying the geomorphologic changes occurred due to the natural disasters and man made activities using 2008, 2010, 2013 satellite Images by adopting Remote Sensing Technologies and GIS tools. The study area is located in Nellore district of Andhra Pradesh, India located between longitude 80° 3?3? to 80° 18?6? and 13 °28? 32? to 13° 57?6? latitude. The study area is covered under the Survey of India (SOI toposheet no 66C/1,2,3,5,6 and 7 with scale 1:50000 and Multi-Spectral imageries from IRS-P6,LISS III,IV data of 2008, 2010 and 2013 Geocoded Satellite data are acquired as primary and secondary data for analysis. Visual Interpretation techniques are used to identify the Geomorphology classes from 2008, 2010 satellite imageries, ground truthing and post interpretation of the satellite image for preparation of 2013 Geomorphology map in this different classes like Creek, Flood Plain, Coastal Plain Moderate, Buried Pedi plain etc. are identified. These spatial data maps generate statistical values of geomorphological classes, from this data analysis was carried out to find out the changes in the Geomorphology classes of 2008 to 2010 and 2010 to 2013. These type of model studies are very useful to identify the coastal geomorphological changes, its impact on coastal environment and in preparing the action plans to protect the coastal environmental.

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

    International Nuclear Information System (INIS)

    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 cm3, 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

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

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

  19. Detection of fog layers characteristics with ground-based remote sensing equipments

    Science.gov (United States)

    Toanca, Florica; Stefan, Sabina; Binietoglou, Ioannis; Labzovskii, Lev; Stefanie, Horatiu

    2015-04-01

    Fog is one of the phenomena that generates important economic problems and also impacts a broad variety of human activities. This study aims to determine fog layers characteristics in terms of type, time evolution, and vertical extent in Magurele, Romania (44.35 N, 26.03 E) for two periods (2012 and 2013). Data regarding fog evolution was provided by a Vaisala CL31 Ceilometer and a HATPRO Microwave Radiometer. Ceilometer profiles are obtained with a time resolution of 16 s and up to 7.5 km altitude. Microwave radiometer uses passive microwave detection in the 22.335 to 31.4 GHz and 51 to 58 GHz bands to obtain the vertical profiles of temperature and relative humidity up to 10 km with a temporal resolution of several minutes. MWR also provide integrated water vapor and liquid water path. Considering all this information from active and passive remote sensing instruments, we present preliminary results towards a method for fog type classification. The extended database containing fog measurements for a two years period is used in a statistical analysis of the evolution and geometrical properties for each fog type. Acknowledgements The work was supported by the strategic grant POSDRU/159/1.5/S/137750, "Project Doctoral and Postdoctoral programs support for increased competitiveness in Exact Sciences research" co financed by the European Social Found within the Sectorial Operational Program Human Resources Development 2007-2013 and by a grant of the STAR-ESA Programme 39/2012-SIAFIM.

  20. Detection of Usefullness of Integrating Remotely Sensed Data (Landsat TM with GIS

    Directory of Open Access Journals (Sweden)

    H. Abdul Halim

    2006-01-01

    Full Text Available A study integrating remote sensing and Geographical Information System (GIS was carried out in the Kuala Terengganu district, Terengganu, Malaysia to map and determine the land use change as a result of development pressure in the area. Two sets of Landsat Thematic Mapper (TM dated 31 July 1988 and 14 July 2002, at scale 1: 150 000 were acquired. Land use classes were interpreted from these images and the resultant maps were checked in the field to determine ground truth and mapping accuracy. The land use map data were transferred directly into the computer via ILWIS (Integrated Land Water and Water Information System version 3.1 software. It shown that in this study seven categories of land use changes were detected namely forest (-9.93%, agricultural (-1.46%, swamp (-36.92%, urban (190.29%, cleared land (-21.43%, water bodies (-7.48% and bush/shrub (6.34%. The accuracy assessment undertaken showed that the total accuracy for produced the map is 77.89%. This study showed that Landsat TM is a useful data for study in land use change.

  1. Surface biosignatures of exo-Earths: Remote detection of extraterrestrial life.

    Science.gov (United States)

    Hegde, Siddharth; Paulino-Lima, Ivan G; Kent, Ryan; Kaltenegger, Lisa; Rothschild, Lynn

    2015-03-31

    Exoplanet discovery has made remarkable progress, with the first rocky planets having been detected in the central star's liquid water habitable zone. The remote sensing techniques used to characterize such planets for potential habitability and life rely solely on our understanding of life on Earth. The vegetation red edge from terrestrial land plants is often used as a direct signature of life, but it occupies only a small niche in the environmental parameter space that binds life on present-day Earth and has been widespread for only about 460 My. To more fully exploit the diversity of the one example of life known, we measured the spectral characteristics of 137 microorganisms containing a range of pigments, including ones isolated from Earth's most extreme environments. Our database covers the visible and near-infrared to the short-wavelength infrared (0.35-2.5 µm) portions of the electromagnetic spectrum and is made freely available from biosignatures.astro.cornell.edu. Our results show how the reflectance properties are dominated by the absorption of light by pigments in the visible portion and by strong absorptions by the cellular water of hydration in the infrared (up to 2.5 µm) portion of the spectrum. Our spectral library provides a broader and more realistic guide based on Earth life for the search for surface features of extraterrestrial life. The library, when used as inputs for modeling disk-integrated spectra of exoplanets, in preparation for the next generation of space- and ground-based instruments, will increase the chances of detecting life. PMID:25775594

  2. 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 per 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

  3. Land use and land cover change detection in Isfahan, Iran using remote sensing techniques

    Science.gov (United States)

    Alavi, Niloofar

    Rapid urban growth and unprecedented rural to urban transition, along with a huge population growth are new phenomena for both high and low income countries, which started in the mid-20th century. However, urban growth rates and patterns are different in developed countries and developing ones. In less developed countries, urbanization and rural to urban transition usually takes place in an unmanaged way and they are associated with a series of socioeconomical and environmental issues and problems. Identification of the city growth trends in past decades can help urban planners and managers to minimize these negative impacts. In this research, urban growth in the city of Isfahan, Iran, is the subject of study. Isfahan the third largest city in Iran has experienced a huge urban growth and population boom during the last three decades. This transition led to the destruction of natural and agricultural lands and environmental pollutions. Historical and recent remotely sensed data, along with different remote sensing techniques and methods have been used by researchers for urban land use and land cover change detection. In this study three Landsat TM and ETM+ images of the study site, acquired in 1985, 2000 and 2009 are used. Before starting processing, radiometric normalization is done to minimize the atmospheric effects. Then, processing methods including principal component analysis (PCA), vegetation indices and supervised classification are implemented on the images. Accuracy assessment of the PCA method showed that the first PC was responsible for more than 81% of the total variance, and therefore used for analysis of PCA differencing. DeltaPC1t1-t2 shows the amount of changes in land use and land cover during the period of study. In this study ten vegetation indices were selected to be applied to the 1985 image. Accuracy assessments showed that Transformed Differencing Vegetation Index (TDVI) is the most sensitive and accurate index for mapping vegetation in arid and semi-arid urban areas. Hence, TDVI was applied to the 2000 and 2009 images. DeltaTDVIt1-t2 showed the changes in land use and land cover especially the land use transformation from vegetation cover into the urban class. Supervised classification is the last method applied to the images. Training sites were assigned for the selected classes and accuracy was monitored during the process of training site selection. The results of classification show the expansion of urban class and diminishment in natural and agricultural lands.

  4. Hybrid nanoparticle-microcavity-based plasmonic nanosensors with improved detection resolution and extended remote-sensing ability

    Science.gov (United States)

    Schmidt, Markus A.; Lei, Dang Yuan; Wondraczek, Lothar; Nazabal, Virginie; Maier, Stefan A.

    2012-10-01

    Optical nanosensors based on plasmonic nanoparticles have great potential for chemical and biological sensing applications, but their spectral detection resolution is severely constrained by their broad resonance linewidth, and their spatial sensing depth is limited to several tens of nanometres. Here we demonstrate that coupling a strong dipolar plasmonic resonance of a single metallic nanoparticle to the narrow bandwidth resonances of an optical microcavity creates a hybrid mode and discretizes the broad localized resonance, boosting the sensing figure-of-merit by up to 36 times. This cavity-nanoparticle system effectively combines the advantages of Fabry-Perot microresonators with those of plasmonic nanoparticles, providing interesting features such as remote-sensing ability, incident-angle independent resonances, strong polarization dependence, lateral ultra small sensing volume and strongly improved detection resolution. Such a hybrid system can be used not only to locally monitor specific dynamic processes in biosensing, but also to remotely sense important film parameters in thin-film nanometrology.

  5. Spinal fMRI during proprioceptive and tactile tasks in healthy subjects: activity detected using cross-correlation, general linear model and independent component analysis

    International Nuclear Information System (INIS)

    Functional MRI (fMRI) of the spinal cord is able to provide maps of neuronal activity. Spinal fMRI data have been analyzed in previous studies by calculating the cross-correlation (CC) between the stimulus and the time course of every voxel and, more recently, by using the general linear model (GLM). The aim of this study was to compare three different approaches (CC analysis, GLM and independent component analysis (ICA)) for analyzing fMRI scans of the cervical spinal cord. We analyzed spinal fMRI data from healthy subjects during a proprioceptive and a tactile stimulation by using two model-based approaches, i.e., CC analysis between the stimulus shape and the time course of every voxel, and the GLM. Moreover, we applied independent component analysis, a model-free approach which decomposes the data in a set of source signals. All methods were able to detect cervical cord areas of activity corresponding to the expected regions of neuronal activations. Model-based approaches (CC and GLM) revealed similar patterns of activity. ICA could identify a component correlated to fMRI stimulation, although with a lower statistical threshold than model-based approaches, and many components, consistent across subjects, which are likely to be secondary to noise present in the data. Model-based approaches seem to be more robust for estimating task-related activity, whereas ICA seems to be useful for eliminating noise components from the data. Combined use of ICA and GLM might imprta. Combined use of ICA and GLM might improve the reliability of spinal fMRI results. (orig.)

  6. Spinal fMRI during proprioceptive and tactile tasks in healthy subjects: activity detected using cross-correlation, general linear model and independent component analysis

    Energy Technology Data Exchange (ETDEWEB)

    Valsasina, P.; Agosta, F.; Filippi, M. [Scientific Institute Ospedale San Raffaele, Neuroimaging Research Unit, Milan (Italy); Caputo, D. [Scientific Institute Fondazione Don Gnocchi, Department of Neurology, Milan (Italy); Stroman, P.W. [Queen' s University, Department of Diagnostic Radiology, Centre for Neuroscience Studies, Kingston, ON (Canada)

    2008-10-15

    Functional MRI (fMRI) of the spinal cord is able to provide maps of neuronal activity. Spinal fMRI data have been analyzed in previous studies by calculating the cross-correlation (CC) between the stimulus and the time course of every voxel and, more recently, by using the general linear model (GLM). The aim of this study was to compare three different approaches (CC analysis, GLM and independent component analysis (ICA)) for analyzing fMRI scans of the cervical spinal cord. We analyzed spinal fMRI data from healthy subjects during a proprioceptive and a tactile stimulation by using two model-based approaches, i.e., CC analysis between the stimulus shape and the time course of every voxel, and the GLM. Moreover, we applied independent component analysis, a model-free approach which decomposes the data in a set of source signals. All methods were able to detect cervical cord areas of activity corresponding to the expected regions of neuronal activations. Model-based approaches (CC and GLM) revealed similar patterns of activity. ICA could identify a component correlated to fMRI stimulation, although with a lower statistical threshold than model-based approaches, and many components, consistent across subjects, which are likely to be secondary to noise present in the data. Model-based approaches seem to be more robust for estimating task-related activity, whereas ICA seems to be useful for eliminating noise components from the data. Combined use of ICA and GLM might improve the reliability of spinal fMRI results. (orig.)

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

    Directory of Open Access Journals (Sweden)

    Reza Farjad

    2010-05-01

    Full Text Available 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, prior to surgery as gold standard. Two experienced radiologists reported images. For each sequence, the mean sensitivity, specificity, and predictive values (positive [PPV] and negative [NPV] of MRI were calculated and the interobserver agreement between the two radiologists was assessed by kappa statistics."nResults: Surgery proved 16 cases of cholesteatoma (size: 1.5-60mm. For delayed post-contrast, the mean sensitivity, specificity, PPV and NPV were 75.1%, 85.7%, 92.3% and 60.6%, respectively. These findings were 56.3%, 85.7%, 89.9% and 46.5% for EPI and 90.7%, 100%, 100% and 82.7% for non-EPI. Kappa agreement for delayed post-contrast, EPI and non-EPI DW MRI were 0.83, 0.58 and 0.91, respectively. The detection rate of non-EPI was significantly better than EPI DW MRI for both radiologists (ps<0.05. The mean detection rate (sensitivity of non-EPI (90.7% was statistically better than the delayed post-contrast (75.1% (P<0.05. One patient had cholesteatoma sized 1.5mm in surgery that was missed in all the sequences. There was a false positive case in EPI sequence that was proved as eosinophilic granuloma. "nConclusion: Both delayed post-contrast and non-EPI DW MRI are valuable methods in detecting cholesteatoma. Non-EPI DW sequence is, however, much more accurate. EPI DW sequence does not show enough efficacy in detecting cholesteatoma.

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

    Energy Technology Data Exchange (ETDEWEB)

    Heusner, Till; Goelitz, Philipp [Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University at Duisburg-Essen, Hufelandstrasse 55, 45122 Essen (Germany); Hamami, Monia [Department of Nuclear Medicine, University Hospital Essen, University at Duisburg-Essen, Hufelandstrasse 55, 45122 Essen (Germany); Eberhardt, Wilfried [Department of Medicine (Cancer Research), West German Tumor Centre, University Hospital Essen, University at Duisburg-Essen, Hufelandstrasse 55, 45122 Essen (Germany); Esser, Stefan [Department of Dermatology, University Hospital Essen, University at Duisburg-Essen, Hufelandstrasse 55, 45122 Essen (Germany); Forsting, Michael [Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University at Duisburg-Essen, Hufelandstrasse 55, 45122 Essen (Germany); Bockisch, Andreas [Department of Nuclear Medicine, University Hospital Essen, University at Duisburg-Essen, Hufelandstrasse 55, 45122 Essen (Germany); Antoch, Gerald, E-mail: gerald.antoch@uk-essen.de [Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, University at Duisburg-Essen, Hufelandstrasse 55, 45122 Essen (Germany)

    2011-06-15

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

  9. Comparison of different MRI sequences in lesion detection and early response evaluation of diffuse large B-cell lymphoma--a whole-body MRI and diffusion-weighted imaging study.

    Science.gov (United States)

    Wu, Xingchen; Nerisho, Seyoum; Dastidar, Prasun; Ryymin, Pertti; Järvenpää, Ritva; Pertovaara, Hannu; Eskola, Hannu; Kellokumpu-Lehtinen, Pirkko-Liisa

    2013-09-01

    To compare different MRI sequences for the detection of lesions and the evaluation of response to chemotherapy in patients with diffuse large B-cell lymphoma (DLBCL), 18 patients with histology-confirmed DLBCL underwent 3-T MRI scanning prior to and 1 week after chemotherapy. The MRI sequences included T1-weighted pre- and post-contrast, T2 -weighted with and without fat suppression, and a single-shot echo-planar diffusion-weighted imaging (DWI) with two b values (0 and 800 s/mm(2)). Conventional MRI sequence comparisons were performed using the contrast ratio between tumor and normal vertebral body instead of signal intensity. The apparent diffusion coefficient (ADC) of the tumor was measured directly on the parametric ADC map. The tumor volume was used as a reference for the evaluation of chemotherapy response. The mean tumor volume was 374 mL at baseline, and decreased by 65% 1 week after chemotherapy (p < 0.01). The T2 -weighted image with fat suppression showed a significantly higher contrast ratio compared with images from all other conventional MRI sequences, both before and after treatment (p < 0.01, respectively). The contrast ratio of the T2 -weighted image with fat suppression decreased significantly (p < 0.01), and that of the T1 -weighted pre-contrast image increased significantly (p < 0.01), after treatment. However, there was no correlation between the change in contrast ratio and tumor volume. The mean ADC value was 0.68 × 10(-3) mm(2)/s at baseline; it increased by 89% after chemotherapy (p < 0.001), and the change in ADC value correlated with the change in tumor volume (r = 0.66, p < 0.01). The baseline ADC value also correlated inversely with the percentage change in ADC after treatment (r = -0.62, p < 0.01). In conclusion, this study indicates that T2-weighted imaging with fat suppression is the best conventional sequence for the detection of lesions and evaluation of the efficacy of chemotherapy in DLBCL. DWI with ADC mapping is an imaging modality with both diagnostic and prognostic value that could complement conventional MRI. PMID:23483722

  10. Magnetic Resonance Imaging (MRI)

    Science.gov (United States)

    ... It also helps doctors see inside joints, cartilage, ligaments, and tendons. MRI lets doctors detect problems in the brain, spinal cord, skeleton, chest, lungs, abdomen, pelvis, wrists, hands, ankles, and feet. It helps doctors identify infections and ...

  11. Computer-aided diagnosis for prostate cancer detection in the peripheral zone via multisequence MRI

    Science.gov (United States)

    Niaf, Emilie; Rouvière, Olivier; Lartizien, Carole

    2011-03-01

    We propose a Computer Assisted Diagnosis Interview (CADi) scheme for determining a likelihood measure of prostate cancer presence in the peripheral zone (PZ) based on multisequence magnetic resonance imaging, including T2-weighted (T2w), diffusion-weighted (DWI) and dynamic contrast-enhanced (DCE) MRI at 1.5 Tesla (T). Based on a feature set derived from the gray level images, including first order statistics, Haralick's features, gradient features, semi-quantitative and quantitative (pharmacokinetic modeling) dynamic parameters, we trained and compared four kinds of classifiers: Support Vector Machine (SVM), Linear Discriminant Analysis (LDA), k-Nearest Neighbours (KNN) and Naïve Bayes (NB). The aim is twofold: we try to discriminate between the relevant features as well as creating an efficient classifier using these features. The database consists of 23 radical prostatectomy patients. Using histologic sections as the gold standard, both cancers and non-malignant tissues (suspicious and clearly benign) were annotated in consensus on all MR images by two radiologists, a histopathologist and a researcher. Diagnostic performances were evaluated based on a ROC curves analysis. From the outputs of all evaluated feature selection methods on the test bench, we discriminated a restrictive set of about 20 highly informative features. Quantitative evaluation of the diagnostic performance yielded to a maximal Area Under the ROC Curve (AUC) of 0.89. Moreover, the optimal CADi scheme outperformed, in terms of specificity, our human experts in differentiating malignant from suspicious tissues, thus demonstrating its potential for assisting cancer identification in the PZ.

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

    Directory of Open Access Journals (Sweden)

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

    2012-12-01

    Full Text Available Land Use is clearly constrained by environmental factors like soil characteristics, climatic conditions, water sources and vegetation. Changes in Land Use and Land Cover is a dynamic process taking place on the earth surface, and the spatial distribution of the changes that have taken place over a period of time and space is of immense importance in many natural studies. Whether regional or local in scope, remote sensing offers a means of acquiring and presenting land cover data in timely manner. The environmental factors reflect the importance of land as a key and finite resource for most human activities including agriculture, industry, forestry, energy production, settlement, recreation and water sources and storage.Often improper land use is causing various forms of environmental humiliation. For sustainable utilization of the land ecosystems, it is essential to know the natural characteristics, extent and location, its quality, productivity, suitability and limitations of various land uses. Land use is a product of interactions between a society’s cultural background, state and itsphysical needs on the one hand, and the natural potential of land on the other. In order to improve the economic condition of the area without further deteriorating the bio environment, every bit of the available land has to be used in the most rational way. This requires the present and the past land use/land cover data of the Coimbatore district.Land use / Land cover change has become an important component in current strategies for managing natural resources and monitoring environmental changes. The advancement in the concept of vegetation of the spread and health of the world’s forest, grassland and agricultural resources has become an important priority. Viewing the earth from space is now crucial to the understanding of the influence of man’s activities on his natural resource base over time. Over past years, data fromEarth sensing satellites (digital imagery has become vital in mapping the Earth’s features and infrastructures, managing natural resources and studying environmental change.

  13. Inner ear malformations in patients with sensorineural heating loss: detection with gradient-echo (3DFT-CISS) MRI

    International Nuclear Information System (INIS)

    The sensitivity of different MRI sequences in the detection of inner ear malformations in patients presenting with sensorineural hearing loss (SNHL) and/or vertigo was evaluated. We studied 650 patients presenting with SNHL and/or vertigo, clinically not suspected of having inner ear malformations. The sensitivity of T1-weigted, Gd-enhanced T1-weighted and (when available) T2-weighted spin-echo images, and three-dimensional Fourier transformation-constructive interference in steady state (3DFT-CISS) gradient-echo images, to unexpected malformations was assessed. Inner ear malformations were found in 15 (2.3%) of these patients. Enlargement of the endolymphatic duct and sac was the most frequent malformation, found in 11 patients. The 3DFT-CISS images showed all lesions; the other sequences were less sensitive and the pathology was missed, partially or only retrospectively seen in 11 of the 15 patients. Therefore, in addition to the routine unenhanced and Gd-enhanced T1-weighted and T2-weighted images, thin gradient-echo (3DFT-CISS) images are necessary to detect all clinically unexpected inner ear malformations in patients presenting with vertigo and/or SNHL. (orig.)

  14. Aiming for a shorter rheumatoid arthritis MRI protocol: can contrast-enhanced MRI replace T2 for the detection of bone marrow oedema?

    Energy Technology Data Exchange (ETDEWEB)

    Stomp, Wouter; Bloem, Johan L.; Reijnierse, Monique [Leiden University Medical Center, Department of Radiology, P.O. Box 9600, Leiden (Netherlands); Krabben, Annemarie; Heijde, Desiree van der; Huizinga, Tom W.J.; Helm-van Mil, Annette H.M. van der [Leiden University Medical Center, Department of Rheumatology, P.O. Box 9600, Leiden (Netherlands)

    2014-10-15

    To determine whether T1 post-gadolinium chelate images (T1Gd) can replace T2-weighted images (T2) for evaluating bone marrow oedema (BME), thereby allowing a shorter magnetic resonance imaging (MRI) protocol in rheumatoid arthritis (RA). In 179 early arthritis patients and 43 advanced RA patients, wrist and metacarpophalangeal joints were examined on a 1.5-T extremity MRI system with a standard protocol (coronal T1, T2 fat-saturated and coronal and axial T1 fat-saturated after Gd). BME was scored according to OMERACT RAMRIS by two observers with and without T2 images available. Agreement was assessed using intraclass correlation coefficients (ICCs) for semi-quantitative scores and test characteristics with T2 images as reference. Agreement between scores based on T2 and T1Gd images was excellent ICC (0.80-0.99). At bone level, sensitivity and specificity of BME on T1Gd compared to T2 were high for both patient groups and both readers (all ?80 %). T1Gd and T2 images are equally suitable for evaluating BME. Because contrast is usually administered to assess (teno)synovitis, a short MRI protocol of T1 and T1Gd is sufficient in RA. (orig.)

  15. MRI of brachial plexopathies

    International Nuclear Information System (INIS)

    Magnetic resonance imaging (MRI) has become the primary imaging technique in the evaluation of brachial plexus pathology, and plays an important role in the identification, localization, and characterization of the cause. Improvements in MRI technique have helped in detecting changes in the signal intensity of nerves, subtle enhancement, and in detecting perineural pathology, thereby refining the differential diagnosis. The present review of the visualization of brachial plexus abnormalities using MRI is based on a review of 26 cases. The causes include trauma and a spectrum of non-traumatic causes, such as acute idiopathic/viral plexitis, metastases, immune-mediated plexitis, and mass lesions compressing the brachial plexus

  16. Overview of the iCATSI multi-pixels standoff chemical detection sensor and the MR-i imaging spectroradiometer

    Science.gov (United States)

    Prel, Florent; Moreau, Louis; Lavoie, Hugo; Bouffard, François; Vallières, Christian; Roy, Claude; Levesque, Luc

    2010-10-01

    ABB Bomem is expanding its line of infrared remote sensing products with the addition of a new imaging spectroradiometer. The instrument is modular and support several configurations. One of its configurations is a multipixels sensor optimised for differential acquisition in the VLWIR to support research related to chemical detection. In that configuration, the instrument is equipped with a dual-input telescope to perform optical background subtraction. The resulting signal is the differential between the spectral radiance entering each input port. The other configuration is a general purpose imaging spectroradiometer designed to acquire the spectral signature of rapid events and fast targets in infrared. Overview of the design and results from tests and first field trials will be presented.

  17. Whole-body MRI in the detection of bone marrow infiltration in patients with plasma cell neoplasms in comparison to the radiological skeletal survey

    Energy Technology Data Exchange (ETDEWEB)

    Ghanem, Nadir; Lohrmann, Christian; Pache, Gregor; Uhl, Markus; Saueressig, Ulrich; Kotter, Elmar; Langer, Mathias [University Hospital Freiburg, Department of Diagnostic Radiology, Freiburg (Germany); Engelhardt, Monika [University Hospital Freiburg, Department of Hematology and Oncology, Freiburg (Germany)

    2006-05-15

    To compare the diagnostic value of whole-body MRI versus radiological skeletal survey (RSS) in staging patients with plasma cell neoplasms (PCN) and to evaluate the possible therapeutic impact of the replacement of RSS by whole-body MRI. Fifty-four patients with PCN [multiple myeloma (MM), n=47; monoclonal gammopathy of unknown significance (MGUS), n=7] were studied by whole-body MRI and RSS in a monocenter prospective analysis from August 2002 to May 2004. The MRIs were performed using a rolling table platform ''AngioSURF'' for unlimited field of view with a 1.5-T system (Magnetom Sonata/Maestro Class, Siemens Medical Solutions, Erlangen, Germany). A coronal STIR sequence (TR5500-4230/TE102-94/TI160) was used for imaging of the different body regions, including the head, neck, thorax, abdomen, pelvis and upper and lower extremities. The RSS consisted of eight different projections of the axial and appendicular skeleton. In 41/54 (74%) patients, the results of the whole-body MRI and RSS were concordant. In 11/54 (20%) patients, both imaging techniques were negative. Bone involvement was observed in 30/54 (55%) patients; however, whole-body MRI revealed this more extensively than the RSS in 27/30 (90%) patients with concordant positive imaging findings. In 3/30 (10%) patients, both imaging techniques demonstrated a similar extent of bone marrow infiltration. In 10/54 (19%) patients, the whole-body MRI was superior to RSS in detecting bone marrow infiltration, whereas the RSS was negative. In 3/54 (6%) patients, the RSS was proven to be false positive by the clinical course, whereas the whole-body MRI was truly negative. Whole-body MRI is a fast and highly effective method for staging PCN patients by the use of a rolling table platform. Moreover, it is more sensitive and specific than RSS and reveals bone marrow infiltration and extensive disease more reliably. Therefore, whole-body MRI should be performed as an additional method of exactly staging PCN patients and - with more data in the field - may even prove to be an alternate and more sensitive staging procedure than RSS in PCN patients. (orig.)

  18. Longitudinal Evaluation of the Occurrence of MRI-Detectable Bone Marrow Edema in Osteoarthritis of the Knee

    International Nuclear Information System (INIS)

    Background: Bone marrow edema (BME) is a condition detectable with magnetic resonance imaging (MRI) and is present in different stages of osteoarthritis (OA). Its pathogenesis is still not completely known. Purpose: To evaluate the longitudinal occurrence and persistence of BME in early OA of the knee. Material and Methods: Twenty-three patients (eight females, 15 males; mean age 55.5±10.3 years) were scanned with a 1.5T MR imaging unit (sagittal fat-suppressed intermediate-weighted fast spin echo; 4-mm section thickness, 1-mm intersection gap, 256x192 matrix, 120-mm field of view). Images were obtained in all 23 patients at two time points (TPs) and in 12 patients at three TPs. Images were evaluated by two readers independently; discrepancies in image grading were reviewed and evaluated in consensus. A four-point image-grading scale was used (absence of BME to severe BME). Four main anatomical regions were evaluated (medial femur, lateral femur, medial tibia, lateral tibia), which were subcategorized into anterior, central, and posterior regions. Results: One hundred five areas of BME in the 23 patients were found at all three TPs. In 16 areas, the BME was consistent at the same location over time, in seven locations the BME became larger, in six areas the BME became smaller, and in 16 locations it could not be detected in follow-up MRIs. In one case, the BME was smaller at TP2 but increased at TP3. In eight cases, only at the last time point could a BME be detectede last time point could a BME be detected. Conclusion: BME is not a static phenomenon but changes over time. Correlation to physical activity and local inflammatory reaction should be evaluated

  19. Longitudinal Evaluation of the Occurrence of MRI-Detectable Bone Marrow Edema in Osteoarthritis of the Knee

    Energy Technology Data Exchange (ETDEWEB)

    Brem, M.H.; Schlechtweg, P.M.; Bhagwat, J.; Genovese, M.; Dillingham, M.F.; Yoshioka, H.; Lang, P. (Dept. of Radiology, Brigham and Women' s Hospital, Harvard Medical School, Boston, MA (United States))

    2008-11-15

    Background: Bone marrow edema (BME) is a condition detectable with magnetic resonance imaging (MRI) and is present in different stages of osteoarthritis (OA). Its pathogenesis is still not completely known. Purpose: To evaluate the longitudinal occurrence and persistence of BME in early OA of the knee. Material and Methods: Twenty-three patients (eight females, 15 males; mean age 55.5+-10.3 years) were scanned with a 1.5T MR imaging unit (sagittal fat-suppressed intermediate-weighted fast spin echo; 4-mm section thickness, 1-mm intersection gap, 256x192 matrix, 120-mm field of view). Images were obtained in all 23 patients at two time points (TPs) and in 12 patients at three TPs. Images were evaluated by two readers independently; discrepancies in image grading were reviewed and evaluated in consensus. A four-point image-grading scale was used (absence of BME to severe BME). Four main anatomical regions were evaluated (medial femur, lateral femur, medial tibia, lateral tibia), which were subcategorized into anterior, central, and posterior regions. Results: One hundred five areas of BME in the 23 patients were found at all three TPs. In 16 areas, the BME was consistent at the same location over time, in seven locations the BME became larger, in six areas the BME became smaller, and in 16 locations it could not be detected in follow-up MRIs. In one case, the BME was smaller at TP2 but increased at TP3. In eight cases, only at the last time point could a BME be detected. Conclusion: BME is not a static phenomenon but changes over time. Correlation to physical activity and local inflammatory reaction should be evaluated.

  20. Wallerian degeneration of the corticodescending tract in the cerebral peduncle following a supratentorial cerebrovascular lesion detected by MRI

    International Nuclear Information System (INIS)

    We studied Wallerian degeneration of the corticodescending tract in the cerebral peduncle following a supratentorial cerebrovascular lesion by MRI. A total of 57 patients with palsy following a supratenotorial cerebrovascular lesion were prospectively studied. Wallerian degeneration was detected as a high signal intensity (HSI) in 37 patients between 70 days and 100 days after the onset, but not detected in the remaining 27 patients. Patient with as HSI in all areas of the cerebral peduncle had a large lesion involving the hemisphere. Patient with an HSI at the center of the cerebral peduncle had a lesion confined to the paracentral gyrus, precentral gyrus, corona radiata or posterior limb of the internal capsule. Patient with an HSI at the lateral side of the cerebral peduncle had a lesion of parietal lobe or temporal lobe which spares the corticospinal tract originating from the paracentral gyrus, precentral gyrus, corona radiata or posterior limb of the internal capsule. These findings suggest that as HSI at the center of the cerebral peduncle may reveal Wallerian degeneration of the corticospinal tract, and an HSI at the lateral side of the cerebral peduncle may show Wallerian degeneration of the corticopontine tract. The functional recovery of paresis was poor in all patients with an HSI at the center of the cerebral peduncle, while it was good in all patients without an HSI in that region. Our data suggested that somatotopical localization of the corticodescendiopical localization of the corticodescending tract in the cerebral peduncle may be identified by detecting Wallerian degeneration following a supratentorial lesion, and the functional recovery of patients with paresis could be predicted according to presence or absence of Wallerian degeneration at the center of the cerebral peduncle. (author)

  1. Detection of head and neck squamous cell carcinoma with diffusion weighted MRI after (chemo)radiotherapy: Correlation between radiologic and histopathologic findings

    International Nuclear Information System (INIS)

    Purpose: To investigate the value of diffusion weighted magnetic resonance imaging (DW-MRI) in differentiating persistent or recurrent head and neck squamous cell carcinoma (HNSCC) from nontumoral postradiotherapeutic alterations. Methods and Materials: In 26 patients with suspicion of persistent or recurrent HNSCC, MRI of the head and neck was performed, including routine turbo spin-echo (TSE) sequences and an additional echo-planar DW-MRI sequence, using a large range of b-values (0-1000 s/mm2). Apparent diffusion coefficient (ADC) maps were calculated. In the suspect areas at the primary site and in the suspect lymph nodes, signal intensity was measured on the native b0 and b1000 images and ADC values were calculated for these tissues. The same was done for surrounding irradiated normal tissue. Imaging results were correlated to histopathology. Results: Signal intensity on native b0 images was significantly lower for HNSCC than for nontumoral postradiotherapeutic tissue (p < 0.0001), resulting in a sensitivity of 66.2%, specificity of 60.8%, and accuracy of 62.4%. Signal intensity on native b1000 images was significantly higher for HNSCC than for nontumoral tissue (p < 0.0001), resulting in a sensitivity of 71.6%, specificity of 71.3%, and accuracy of 71.4%. ADC values were significantly lower for HNSCC than for nontumoral tissue (p < 0.0001), resulting in a sensitivity of 94.6%, specificity of 95.9%, and accuracy of 95.5%. When compared with computed toy of 95.5%. When compared with computed tomography, TSE-MRI and fluorodeoxyglucose-positron emission tomography, DW-MRI yielded fewer false-positive results in persistent primary site abnormalities and in persistent adenopathies, and aided in the detection of subcentimetric nodal metastases. Conclusions: Diffusion weighted-MRI accurately differentiates persistent or recurrent HNSCC from nontumoral tissue changes after (chemo)radiotherapy

  2. The role of FDG-PET, HMPAO-SPET and MRI in the detection of brain involvement in patients with systemic lupus erythematosus

    International Nuclear Information System (INIS)

    Involvement of the brain is one of the most important complications of systemic lupus erythematosus (SLE); however, its diagnosis is difficult due to the lack of effective imaging methods. We combined three brain imaging modalities - positron emission tomography with fluorine-18 2-fluoro-2-deoxy-d-glucose (FDG-PET), single-photon emission computed tomography with technetium-99m hexamethylpropylene amine oxime (HMPAO-SPET) and magnetic resonance imaging (MRI) - in order to detect brain involvement in SLE. Thirty-seven SLE patients, aged 22-45 years, were divided into three groups. Group 1 (G1) consisted of ten patients with major neuropsychiatric manifestations; group 2 (G2) consisted of 15 patients with minor manifestations; and group 3 (G3) consisted of 12 patients without manifestations. FDG-PET findings were abnormal in 51% of patients: 90% of G1, 67% of G2 and 0% of G3 patients respectively. HMPAO-SPET findings were abnormal in 62% of patients: 100% of G1, 73% of G2 and 17% of G3 patients respectively. MRI findings were abnormal in 35% of patients: 70% of G1, 40% of G2 and 0% of G3 patients respectively. Grey matter was more commonly involved than white matter; 62% of patients presented with lesions in the cerebral cortex, 27% with lesions in the basal ganglion, 5% with lesions in the cerebellum, and 19% with lesions in white matter. No white matter lesions were found on FDG-PET or HMPAO-SPET. However, in 19% of patients, MRI demonstrated abnormally high signal leMRI demonstrated abnormally high signal lesions in white matter. Forty-three percent of cases had positive serum anticardiolipin antibodies (ACA). However, ACA was not related to FDG-PET, HMPAO-SPET or MRI findings. It may be concluding that HMPAO-SPET is a more sensitive tool for detecting brain involvement in SLE patients when compared with FDG-PET or MRI. However, MRI is necessary for detecting lesions in white matter. (orig.)

  3. Utilization of combined remote sensing techniques to detect environmental variables influencing malaria vector densities in rural West Africa

    Directory of Open Access Journals (Sweden)

    Dambach Peter

    2012-03-01

    Full Text Available Abstract Introduction The use of remote sensing has found its way into the field of epidemiology within the last decades. With the increased sensor resolution of recent and future satellites new possibilities emerge for high resolution risk modeling and risk mapping. Methods A SPOT 5 satellite image, taken during the rainy season 2009 was used for calculating indices by combining the image's spectral bands. Besides the widely used Normalized Difference Vegetation Index (NDVI other indices were tested for significant correlation against field observations. Multiple steps, including the detection of surface water, its breeding appropriateness for Anopheles and modeling of vector imagines abundance, were performed. Data collection on larvae, adult vectors and geographic parameters in the field, was amended by using remote sensing techniques to gather data on altitude (Digital Elevation Model = DEM, precipitation (Tropical Rainfall Measurement Mission = TRMM, land surface temperatures (LST. Results The DEM derived altitude as well as indices calculations combining the satellite's spectral bands (NDTI = Normalized Difference Turbidity Index, NDWI Mac Feeters = Normalized Difference Water Index turned out to be reliable indicators for surface water in the local geographic setting. While Anopheles larvae abundance in habitats is driven by multiple, interconnected factors - amongst which the NDVI - and precipitation events, the presence of vector imagines was found to be correlated negatively to remotely sensed LST and positively to the cumulated amount of rainfall in the preceding 15 days and to the Normalized Difference Pond Index (NDPI within the 500 m buffer zone around capture points. Conclusions Remotely sensed geographical and meteorological factors, including precipitations, temperature, as well as vegetation, humidity and land cover indicators could be used as explanatory variables for surface water presence, larval development and imagines densities. This modeling approach based on remotely sensed information is potentially useful for counter measures that are putting on at the environmental side, namely vector larvae control via larviciding and water body reforming.

  4. From Remotely Sensed Vegetation Onset to Sowing Dates: Aggregating Pixel-Level Detections into Village-Level Sowing Probabilities

    Directory of Open Access Journals (Sweden)

    Eduardo Marinho

    2014-11-01

    Full Text Available Monitoring the start of the crop season in Sahel provides decision makers with valuable information for an early assessment of potential production and food security threats. Presently, the most common method for the estimation of sowing dates in West African countries consists of applying given thresholds on rainfall estimations. However, the coarse spatial resolution and the possible inaccuracy of these estimations are limiting factors. In this context, the remote sensing approach, which consists of deriving green-up onset dates from satellite remote sensing data, appears as an interesting alternative. It builds upon a novel statistic model that translates vegetation onset detections derived from MODIS time series into sowing probabilities at the village level. Results for Niger show that this approach outperforms the standard method adopted in the region based on rainfall thresholds.

  5. Indications for body MRI

    Energy Technology Data Exchange (ETDEWEB)

    Dujardin, M. [Department of Radiology, Vrije Universiteit Brussel, BEFY, Laarbeeklaan 101, 1090 Brussels (Belgium)], E-mail: martine.dujardin@gmail.com; Vandenbroucke, F. [Department of Radiology, Vrije Universiteit Brussel, Laarbeeklaan 101, 1090 Brussels (Belgium)], E-mail: frederik.vandenbroucke@az.vub.ac.be; Boulet, C. [Department of Radiology, Vrije Universiteit Brussel, Laarbeeklaan 101, 1090 Brussels (Belgium)], E-mail: cedric.boulet@az.vub.ac.be; Op de Beeck, B. [Department of Radiology, UZA and Vrije Universiteit Brussel, Laarbeeklaan 101, 1090 Brussels (Belgium)], E-mail: bart.op.de.beeck@uza.be; Mey, J. de [Department of Radiology, Vrije Universiteit Brussel, BEFY, Laarbeeklaan 101, 1090 Brussels (Belgium)], E-mail: johan.demey@az.vub.ac.be

    2008-02-15

    The lack of ionizing radiation use in MRI makes the high spatial resolution technique very appealing. Also, the easy access to multiplanar imaging and the fact that gadolinium-DTPA is well tolerated and not nephrotoxic makes MRI a robust alternative in the healthy as well as the renal compromised patient. Furthermore, MRI adds advanced possibility for tissue characterization and pathology detection and dynamic imaging can be performed. Specific contrast agents specific to the hepatobiliary or the reticuloendothelial system can help with additional information in problem cases. The role of MRI for different organs is discussed and a review of the literature is given. We concluded that MRI is considered a useful and non-invasive diagnostic tool for the detection of hepatic iron concentration, to correct misdiagnosis (pseudolesions) from US and CT in focal steatosis and to help with focal lesion detection and characterization, in the healthy and especially in the cirrhotic liver, where MRI is superior to CT. Moreover, MRCP is excellent for identifying the presence and the level of biliary obstruction in malignant invasion and is considered in the literature as a non-invasive screening tool for common bile duct stones, appropriately selecting candidates for preoperative ERCP and sparing others the need for an endoscopic procedure with its associated complications. MRI is the first choice modality for adrenal evaluation in contemporary medical imaging. It is a useful examination in renal as well as splenic pathology and best assesses loco-regional staging, i.e. arterial involvement in pancreatic cancer.

  6. Detection and Monitoring of E-Waste Contamination through Remote Sensing and Image Analysis

    Science.gov (United States)

    Garb, Yaakov; Friedlander, Lonia

    2015-04-01

    Electronic waste (e-waste) is one of today's fastest growing waste streams, and also one of the more problematic, as this end-of-life product contains precious metals mixed with and embedded in a variety of low value and potentially harmful plastic and other materials. This combination creates a powerful incentive for informal value chains that transport, extract from, and dispose of e-waste materials in far-ranging and unregulated ways, and especially in settings where regulation and livelihood alternatives are sparse, most notably in areas of India, China, and Africa. E-waste processing is known to release a variety of contaminants, such as heavy metals and persistent organic pollutants, including flame retardants, dioxins and furans. In several sites, where the livelihoods of entire communities are dependent on e-waste processing, the resulting contaminants have been demonstrated to enter the hydrological system and food chain and have serious health and ecological effects. In this paper we demonstrate for the first time the usefulness of multi-spectral remote sensing imagery to detect and monitor the release and possibly the dispersal of heavy metal contaminants released in e-waste processing. While similar techniques have been used for prospecting or for studying heavy metal contamination from mining and large industrial facilities, we suggest that these techniques are of particular value in detecting contamination from the more dispersed, shifting, and ad-hoc kinds of release typical of e-waste processing. Given the increased resolution and decreased price of multi-spectral imagery, such techniques may offer a remarkably cost-effective and rapidly responsive means of assessing and monitoring this kind of contamination. We will describe the geochemical and multi-spectral image-processing principles underlying our approach, and show how we have applied these to an area in which we have a detailed, multi-temporal, spatially referenced, and ground-validated inventory of several hundred e-waste processing and disposal sites. We have compiled these data in recent years using field observation, interviews with e-waste workers, and systematic manual inspection of high resolution ortho-photo imagery (Garb and Davis, 2015). Drawing on this inventory, we offer a proof-of-concept demonstration of an image-processing algorithm that can reliably detect such sites. We will also discuss several ways in which we are extending this research. One of these is testing our ability to scale up and apply this approach to similar contamination sites in other geologic contexts. Relatedly, drawing on our extensive chrono-sequence of sites with differing contextual and use characteristics, we are exploring the factors shaping if and how certain soil types and/or local and regional mineral assemblages retain heavy metal contaminants more strongly (and for longer periods of time) than others, or whether these factors mediate contaminant transport.

  7. Pathologically confirmed solitary bone metastasis of extraskeletal maliganacy detected by bone scan: correlation with CT and MRI

    International Nuclear Information System (INIS)

    To determine the significance of solitary bone metastasis at the time of initial staging for the extraskeletal malignancy manifesting as a solitary hot spot in bone scans and to evaluate the scintigraphic features of solitary bone metastasis. Eleven cases of solitary bone metastasis from extraskeletal primary malignancies detected by bone scans during last 5 years were included. Scintigraphic location, extent and pattern of the abnormalities were analyzed. The primary malignancies were from the liver(2), lung(2), esophagus(2), skin(1), thyroid(1), breast(1), kidney(1), and neuroblastoma(1). The locations of lesion were femur(4), spine(3), tibia(2), pelvic bone(1), and rib(1). At the time of initial bone scan, simple radiography in 7 patients were inconclusive for abnormalities. CT or MR imaging were correlated. All lesions were confirmed by histology. In cancer patients with a solitary hot spot in planar bone scan, eccentric uptake pattern of is one of the important diagnostic feature of metastasis from benign arthritic or trauma-related lesions. CT, MRI correlation and biopsy are followed

  8. Follow-up MRI in dural arteriovenous malformations involving the cavernous sinus: Emphasis on detection of venous thrombosis

    Energy Technology Data Exchange (ETDEWEB)

    Hirabuki, N.; Fujita, N.; Hashimoto, T.; Fujii, K.; Miura, T.; Mitomo, M.; Kawai, R.; Kozuka, T. (Osaka Univ. Medical School (Japan). Dept. of Radiology)

    1992-10-01

    Six patients with a dural arteriovenous malformation (dural AVM) involving the cavernous sinus were followed up with magnetic resonance imaging in order to assess change in the lesions. Spin-echo (SE) imaging of three patients in whom the AVM appeared to have closed at least 1 month earlier showed neither apparent flow void in the involved cavernous sinus nor evidence of venous thrombosis. SE images of the other three patients who had not been cured by external carotid artery embolization, detected persisting arteriovenous shunts, including high-flow cortical venous drainage, seen as flow void. Two-dimensional time-of-flight MR angiography (2D TOF MRA) was performed simultaneously in three patients. Whereas shunting blood and the normal cavernous sinus were of high intensity, presumed thrombosed cavernous sinuses were isointense with stationary brain tissue. The aims of this report were to assess the state of a dural AVM of the cavernous sinus by MRI, and to describe a preliminary application of two-dimensional time-of-flight (2D TOF) MRA. (orig./GDG).

  9. Follow-up MRI in dural arteriovenous malformations involving the cavernous sinus: Emphasis on detection of venous thrombosis

    International Nuclear Information System (INIS)

    Six patients with a dural arteriovenous malformation (dural AVM) involving the cavernous sinus were followed up with magnetic resonance imaging in order to assess change in the lesions. Spin-echo (SE) imaging of three patients in whom the AVM appeared to have closed at least 1 month earlier showed neither apparent flow void in the involved cavernous sinus nor evidence of venous thrombosis. SE images of the other three patients who had not been cured by external carotid artery embolization, detected persisting arteriovenous shunts, including high-flow cortical venous drainage, seen as flow void. Two-dimensional time-of-flight MR angiography (2D TOF MRA) was performed simultaneously in three patients. Whereas shunting blood and the normal cavernous sinus were of high intensity, presumed thrombosed cavernous sinuses were isointense with stationary brain tissue. The aims of this report were to assess the state of a dural AVM of the cavernous sinus by MRI, and to describe a preliminary application of two-dimensional time-of-flight (2D TOF) MRA. (orig./GDG)

  10. Computer-Aided Detection and diagnosis for prostate cancer based on mono and multi-parametric MRI: a review.

    Science.gov (United States)

    Lemaître, Guillaume; Martí, Robert; Freixenet, Jordi; Vilanova, Joan C; Walker, Paul M; Meriaudeau, Fabrice

    2015-05-01

    Prostate cancer is the second most diagnosed cancer of men all over the world. In the last few decades, new imaging techniques based on Magnetic Resonance Imaging (MRI) have been developed to improve diagnosis. In practise, diagnosis can be affected by multiple factors such as observer variability and visibility and complexity of the lesions. In this regard, computer-aided detection and computer-aided diagnosis systems have been designed to help radiologists in their clinical practice. Research on computer-aided systems specifically focused for prostate cancer is a young technology and has been part of a dynamic field of research for the last 10 years. This survey aims to provide a comprehensive review of the state-of-the-art in this lapse of time, focusing on the different stages composing the work-flow of a computer-aided system. We also provide a comparison between studies and a discussion about the potential avenues for future research. In addition, this paper presents a new public online dataset which is made available to the research community with the aim of providing a common evaluation framework to overcome some of the current limitations identified in this survey. PMID:25747341

  11. Diffusion MRI abnormalities detection with orientation distribution functions: A multiple sclerosis longitudinal study.

    Science.gov (United States)

    Commowick, Olivier; Maarouf, Adil; Ferré, Jean-Christophe; Ranjeva, Jean-Philippe; Edan, Gilles; Barillot, Christian

    2015-05-01

    We propose a new algorithm for the voxelwise analysis of orientation distribution functions between one image and a group of reference images. It relies on a generic framework for the comparison of diffusion probabilities on the sphere, sampled from the underlying models. We demonstrate that this method, combined to dimensionality reduction through a principal component analysis, allows for more robust detection of lesions on simulated data when compared to classical tensor-based analysis. We then demonstrate the efficiency of this pipeline on the longitudinal comparison of multiple sclerosis patients at an early stage of the disease: right after their first clinically isolated syndrome (CIS) and three months later. We demonstrate the predictive value of ODF-based scores for the early detection of lesions that will appear or heal. PMID:25867549

  12. A Novel Approach for Cancer Detection in MRI Mammogram Using Decision Tree Induction and BPN

    OpenAIRE

    S. Pitchumani Angayarkanni, V. Saravanan

    2011-01-01

    An intelligent computer-aided diagnosis system can be very helpful for radiologist indetecting and diagnosing micro calcifications patterns earlier and faster than typicalscreening programs. In this paper, we present a system based on fuzzy-C Meansclustering and feature extraction techniques using texture based segmentation andgenetic algorithm for detecting and diagnosing micro calcifications’ patterns in digitalmammograms. We have investigated and analyzed a number of feature extractiontech...

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

    Science.gov (United States)

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

    2010-12-01

    We present the first detection of glyoxal (CHOCHO) over the remote tropical Pacific Ocean in the Marine Boundary Layer (MBL). The measurements were conducted by means of the University of Colorado Ship Multi-Axis Differential Optical Absorption Spectroscopy (CU SMAX-DOAS) instrument aboard the research vessel Ronald H. Brown. The research vessel was on a cruise in the framework of the VAMOS Ocean-Cloud-Atmosphere-Land Study - Regional Experiment (VOCALS-REx) and the Tropical Atmosphere Ocean (TAO) projects lasting from October 2008 through January 2009 (74 days at sea). The CU SMAX-DOAS instrument features a motion compensation system to characterize the pitch and roll of the ship and to compensate for ship movements in real time. We found elevated mixing ratios of up to 140 ppt CHOCHO located inside the MBL up to 3000 km from the continental coast over biologically active upwelling regions of the tropical Eastern Pacific Ocean. This is surprising since CHOCHO is very short lived (atmospheric life time ~2 h) and highly water soluble (Henry's Law constant H = 4.2 × 105 M/atm). This CHOCHO cannot be explained by transport of it or its precursors from continental sources. Rather, the open ocean must be a source for CHOCHO to the atmosphere. Dissolved Organic Matter (DOM) photochemistry in surface waters is a source for Volatile Organic Compounds (VOCs) to the atmosphere, e.g. acetaldehyde. The extension of this mechanism to very soluble gases, like CHOCHO, is not straightforward since the air-sea flux is directed from the atmosphere into the ocean. For CHOCHO, the dissolved concentrations would need to be extremely high in order to explain our gas-phase observations by this mechanism (40-70 ?M CHOCHO, compared to ~0.01 ?M acetaldehyde and 60-70 ?M DOM). Further, while there is as yet no direct measurement of VOCs in our study area, measurements of the CHOCHO precursors isoprene, and/or acetylene over phytoplankton bloom areas in other parts of the oceans are too low (by a factor of 10-100) to explain the observed CHOCHO amounts. We conclude that our CHOCHO data cannot be explained by currently understood processes. Yet, it supports first global source estimates of 20 Tg/year CHOCHO from the oceans, which likely is a significant source of secondary organic aerosol (SOA). This chemistry is currently not considered by atmospheric models.

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

    Directory of Open Access Journals (Sweden)

    R. Sinreich

    2010-06-01

    Full Text Available We present the first detection of glyoxal (CHOCHO over the remote tropical Pacific Ocean in the Marine Boundary Layer (MBL. The measurements were conducted by means of the University of Colorado Ship Multi-Axis Differential Optical Spectroscopy (CU SMAX-DOAS instrument aboard the research vessel Ronald H. Brown. The research vessel was on a cruise in the framework of the VAMOS Ocean-Cloud-Atmosphere-Land Study – Regional Experiment (VOCALS-REx and the Tropical Atmosphere Ocean (TAO projects lasting from October 2008 through January 2009 (74 days at sea. The CU SMAX-DOAS instrument features a motion compensation system to characterize the pitch and roll of the ship and to compensate for ship movements in real time. We found elevated mixing ratios of up to 170 ppt CHOCHO located inside the MBL up to 3000 km from the continental coast over biologically active upwelling regions of the tropical Eastern Pacific Ocean. This is surprising since CHOCHO is very short lived (atmospheric life time ~2 h and highly water soluble (Henry's Law constant H=4.2×105 M/atm. This CHOCHO cannot be explained by transport of it or its precursors from continental sources. Rather, the open ocean is a source for CHOCHO to the atmosphere. Dissolved Organic Matter (DOM photochemistry in surface waters is a source for Volatile Organic Compounds (VOCs to the atmosphere, e.g. acetaldehyde. The extension of this mechanism to very soluble gases, like CHOCHO, is not straightforward since the air-sea flux is directed from the atmosphere into the ocean. For CHOCHO, the dissolved concentrations would need to be extremely high in order to explain our gas-phase observations by this mechanism (40–70 ?M CHOCHO, compared to ~0.01 ?M acetaldehyde and 60–70 ?M DOM. Further, while there is as yet no direct measurement of VOCs in our study area, measurements of the CHOCHO precursors isoprene, and/or acetylene over phytoplankton bloom areas in other parts of the oceans are too low (by a factor of 10–100 to explain the observed CHOCHO amounts. We conclude that our CHOCHO data cannot be explained by currently understood processes. Yet, it supports first global source estimates of 20 Tg/year CHOCHO from the oceans, which likely is a significant source of secondary organic aerosol (SOA. This chemistry is currently not considered by atmospheric models.

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

    Directory of Open Access Journals (Sweden)

    R. Sinreich

    2010-12-01

    Full Text Available We present the first detection of glyoxal (CHOCHO over the remote tropical Pacific Ocean in the Marine Boundary Layer (MBL. The measurements were conducted by means of the University of Colorado Ship Multi-Axis Differential Optical Absorption Spectroscopy (CU SMAX-DOAS instrument aboard the research vessel Ronald H. Brown. The research vessel was on a cruise in the framework of the VAMOS Ocean-Cloud-Atmosphere-Land Study – Regional Experiment (VOCALS-REx and the Tropical Atmosphere Ocean (TAO projects lasting from October 2008 through January 2009 (74 days at sea. The CU SMAX-DOAS instrument features a motion compensation system to characterize the pitch and roll of the ship and to compensate for ship movements in real time. We found elevated mixing ratios of up to 140 ppt CHOCHO located inside the MBL up to 3000 km from the continental coast over biologically active upwelling regions of the tropical Eastern Pacific Ocean. This is surprising since CHOCHO is very short lived (atmospheric life time ~2 h and highly water soluble (Henry's Law constant H = 4.2 × 105 M/atm. This CHOCHO cannot be explained by transport of it or its precursors from continental sources. Rather, the open ocean must be a source for CHOCHO to the atmosphere. Dissolved Organic Matter (DOM photochemistry in surface waters is a source for Volatile Organic Compounds (VOCs to the atmosphere, e.g. acetaldehyde. The extension of this mechanism to very soluble gases, like CHOCHO, is not straightforward since the air-sea flux is directed from the atmosphere into the ocean. For CHOCHO, the dissolved concentrations would need to be extremely high in order to explain our gas-phase observations by this mechanism (40–70 ?M CHOCHO, compared to ~0.01 ?M acetaldehyde and 60–70 ?M DOM. Further, while there is as yet no direct measurement of VOCs in our study area, measurements of the CHOCHO precursors isoprene, and/or acetylene over phytoplankton bloom areas in other parts of the oceans are too low (by a factor of 10–100 to explain the observed CHOCHO amounts. We conclude that our CHOCHO data cannot be explained by currently understood processes. Yet, it supports first global source estimates of 20 Tg/year CHOCHO from the oceans, which likely is a significant source of secondary organic aerosol (SOA. This chemistry is currently not considered by atmospheric models.

  16. Novel Membrane-Permeable Contrast Agent for Brain Tumor Detection by MRI

    OpenAIRE

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

    2010-01-01

    One of the key challenges hindering the clinical intervention against brain cancer is defined by the inability to detect brain tumors at an early enough stage to permit effective therapy. Furthermore, the rapid growth and severe lethality of this form of cancer predicate the vital importance of monitoring the development of the pathology and its outcome after therapeutic intervention. With this in mind, we designed a novel membrane-permeant contrast agent, MN-MPAP-Cy5.5, which consists of a s...

  17. Detection and quantification of remote microglial activation in rodent models of focal ischaemia using the TSPO radioligand CLINDE

    International Nuclear Information System (INIS)

    Neuroinflammation is involved in stroke pathophysiology and might be imaged using radioligands targeting the 18 kDa translocator protein (TSPO). We studied microglial reaction in brain areas remote from the primary lesion site in two rodent models of focal cerebral ischaemia (permanent or transient) using [125I]-CLINDE, a promising TSPO single photon emission computed tomography radioligand. In a mouse model of permanent middle cerebral artery occlusion (MCAO), ex vivo autoradiographic studies demonstrated, besides in the ischaemic territory, accumulation of [125I]-CLINDE in the ipsilateral thalamus with a binding that progressed up to 3 weeks after MCAO. [125I]-CLINDE binding markedly decreased in animals pre-injected with either unlabelled CLINDE or PK11195, while no change was observed with flumazenil pre-treatment, demonstrating TSPO specificity. In rats subjected to transient MCAO, [125I]-CLINDE binding in the ipsilateral thalamus and substantia nigra pars reticulata (SNr) was significantly higher than that in contralateral tissue. Moreover, [125I]-CLINDE binding in the thalamus and SNr was quantitatively correlated to the ischaemic volume assessed by MRI in the cortex and striatum, respectively. Clinical consequences of secondary neuronal degeneration in stroke might be better treated thanks to the discrimination of neuronal processes using in vivo molecular imaging and potent TSPO radioligands like CLINDE tand potent TSPO radioligands like CLINDE to guide therapeutic interventions. (orig.)

  18. Detection and quantification of remote microglial activation in rodent models of focal ischaemia using the TSPO radioligand CLINDE

    Energy Technology Data Exchange (ETDEWEB)

    Arlicot, Nicolas [Universite Francois Rabelais de Tours, CHRU de Tours (France). UMR Inserm U 930, CNRS ERL 3106; UFR Sciences Pharmaceutiques, Laboratoire de Biophysique, Tours (France); Petit, Edwige; Toutain, Jerome; Divoux, Didier; Roussel, Simon; Bernaudin, Myriam [Universite de Caen Basse-Normandie, Universite Paris-Descartes, CNRS, CEA CYCERON, Caen (France). Equipe CERVOxy ' ' Hypoxie et Physiopathologie cerebrovasculaire' ' , UMR 6232 CI-NAPS; Katsifis, Andrew [ANSTO, Radiopharmaceuticals Research Institute, Menai (Australia); Bodard, Sylvie; Guilloteau, Denis; Chalon, Sylvie [Universite Francois Rabelais de Tours, CHRU de Tours (France). UMR Inserm U 930, CNRS ERL 3106

    2010-12-15

    Neuroinflammation is involved in stroke pathophysiology and might be imaged using radioligands targeting the 18 kDa translocator protein (TSPO). We studied microglial reaction in brain areas remote from the primary lesion site in two rodent models of focal cerebral ischaemia (permanent or transient) using [{sup 125}I]-CLINDE, a promising TSPO single photon emission computed tomography radioligand. In a mouse model of permanent middle cerebral artery occlusion (MCAO), ex vivo autoradiographic studies demonstrated, besides in the ischaemic territory, accumulation of [{sup 125}I]-CLINDE in the ipsilateral thalamus with a binding that progressed up to 3 weeks after MCAO. [{sup 125}I]-CLINDE binding markedly decreased in animals pre-injected with either unlabelled CLINDE or PK11195, while no change was observed with flumazenil pre-treatment, demonstrating TSPO specificity. In rats subjected to transient MCAO, [{sup 125}I]-CLINDE binding in the ipsilateral thalamus and substantia nigra pars reticulata (SNr) was significantly higher than that in contralateral tissue. Moreover, [{sup 125}I]-CLINDE binding in the thalamus and SNr was quantitatively correlated to the ischaemic volume assessed by MRI in the cortex and striatum, respectively. Clinical consequences of secondary neuronal degeneration in stroke might be better treated thanks to the discrimination of neuronal processes using in vivo molecular imaging and potent TSPO radioligands like CLINDE to guide therapeutic interventions. (orig.)

  19. Study on the photoacoustic spectroscopy capabilities with remote detection for monitoring of actinide species in nuclear fuel reprocessing solutions

    International Nuclear Information System (INIS)

    A LIPAS (Laser Induced Photoacoustic Spectroscopy) system has been developed for remote analysis of weakly absorbing species in solution. A number of photoacoustic cells of various configurations have been examined in remote arrangement of PA spectrometer with application of an optical fiber for the laser light transmission to PA cell. A microscope objective was tested in optical fiber launching arrangement to collimate laser beam after the fiber. It has been shown that short optical pathlengh cuvette type cells in combination with a disk type piezoelectric transducer (PZT) are superior to previously used cylindrical PA cell with a tube type PZT as regards more effective elimination of scattered and reflected light contribution to PZT response. This allows to improve the linearity of calibration curve and to lower the detection limit absorptivity down to 4.2x10-5cm-1, which has been evaluated using an absorption band of Nd at 511.4 nm. The newly designed PA cell has been applied for investigation of PAS capabilities to detection of Pu(III), Pu(IV) and Pu(VI) simulated species in uranium containing solutions relevant to the nuclear fuel reprocessing technology. It has been shown that the proper selection of plutonium absorption band for each oxidation state allows to reduce high background contribution from U(VI) ions to the analytical PA signal and to keep detection limit absorptivity within a 1-3x10-5cm-1 range in the 525-562 nm wavelength region. (author)

  20. Use of a remote sensing approach to detect landslide thermal behaviour

    Science.gov (United States)

    Mondini, A.; Carlà, R.; Reichenbach, P.; Cardinali, M.; Guzzetti, F.

    2009-04-01

    The type, abundance and distribution of landsides in an area are controlled by the morphological, lithological and land use settings, and by the intensity and frequency of the triggers. Knowing the location and abundance of landslides is important for scientific and societal reasons. Most commonly, geomorphologists map landslides in the field or through the interpretation of stereoscopic aerial photographs. These are expensive and time consuming operations that require experienced personnel. The possibility to detect and map landslides over large area using remote sensing technology will improve the current capability to predict landslides, and to evaluate the susceptibility of an area to slope instability phenomena. In this work, we exploit airborne and space borne optical (thermal) imagery to evaluate the possibility to detect and map landslides. For the experiment, we select the Collazzone study area, that extend for about 80 square kilometers in Umbria, central Italy. For this area, detailed geomorphological information exists, including a multi-temporal landslide inventory map at 1:10,000 scale. We make the hypothesis that a difference in surface temperature exists between landslide and stable areas, due to different soil moisture conditions. We verify the hypothesis at two geographical scales: (i) at the (large) "single landslide" scale, and (ii) at the (small) catchment scale. Both approaches require the measurement of surface temperature at multiple sites, and the production of Land Surface Temperature (LST) maps. For individual landslides, we use images obtained on 3 May 2004 by a Daedalus 1268 Airborne Thematic Mapper (ATM), flown onboard a Dornier 228-110 aircraft operated by the Airborne Research and Survey Facility (ARSF) of the UK National Environment Research Council (NERC). For our catchment scale analysis, we use a L1A satellite image obtained on 3 July 2004 and acquired by ASTER sensor onboard TERRA satellite and a L1G satellite image obtained on 3 August 2001 by ETM+ sensor onboard LANDSAT 7. For our large scale, individual landslide, analysis we perform a pixel by pixel comparison of the surface temperature measurements obtained by processing the ATM data inside individual landslides, and in the immediately surrounding stable areas. For our basin scale analysis, we overlay in a GIS a map of surface temperature, obtained by processing the ASTER and LANDSAT images, on the landslide inventory map. We then compare the statistical distributions of the surface temperature measured in landslide and in stable areas. Preliminary results indicate that the mean and the mode of the distribution of surface temperature in landslide areas are lower than in the stable areas. This is consistent with the observation that in the study area landslides are wetter than stable areas. When studying individual landslides the distinction is less clear, but pixels located inside landslides are, in general, colder (i.e., wetter) than those located in the immediately surrounding stable areas where land cover types are similar.

  1. Impact of functional MRI data preprocessing pipeline on default-mode network detectability in patients with disorders of consciousness

    OpenAIRE

    Andronache, Adrian; Rosazza, Cristina; Sattin, Davide; Leonardi, Matilde; D'Incerti, Ludovico; Minati, Ludovico

    2013-01-01

    An emerging application of resting-state functional MRI (rs-fMRI) is the study of patients with disorders of consciousness (DoC), where integrity of default-mode network (DMN) activity is associated to the clinical level of preservation of consciousness. Due to the inherent inability to follow verbal instructions, arousal induced by scanning noise and postural pain, these patients tend to exhibit substantial levels of movement. This results in spurious, non-neural fluctuations of the rs-fMRI ...

  2. Near IR diodes as illumination sources to remotely detect under-drawings on century-old paintings

    Science.gov (United States)

    Strojnik, Marija; Paez, Gonzalo; Ortega, Antonio

    2011-08-01

    Mexico possesses a large cultural heritage of paintings, elaborated after the European explorers encountered the New World. The interest in documenting these treasures was recently renewed, with the development of nondestructive remote techniques. We examined an undocumented painting for the presence of any invisible signatures, dates, or under-drawings. We employed several illumination-detection schemes, including IR broadband and LED arrays to achieve this purpose. We made visible the signature at about 1 ?m and the date at 1.2 ?m.

  3. The role of FDG-PET, HMPAO-SPET and MRI in the detection of brain involvement in patients with systemic lupus erythematosus

    Energy Technology Data Exchange (ETDEWEB)

    Kao Chiahung [Department of Nuclear Medicine, Taichung Veterans General Hospital, Taichung (Taiwan, Province of China); Lan Jungliang [Division of Rheumatology, Taichung Veterans General Hospital, Taichung (Taiwan, Province of China); ChangLai Shengping [Department of Nuclear Medicine, Chung-Shan Medical and Dental College, Taichung (Taiwan, Province of China); Liao Kokaung [Electron Microscopic Laboratory, Chung-Shan Medical and Dental College, Taichung (Taiwan, Province of China); Yen Rouhfang; Chieng Poonung [Department of Nuclear Medicine, National Taiwan University Hospital, Taipei (Taiwan, Province of China)

    1999-02-01

    Involvement of the brain is one of the most important complications of systemic lupus erythematosus (SLE); however, its diagnosis is difficult due to the lack of effective imaging methods. We combined three brain imaging modalities - positron emission tomography with fluorine-18 2-fluoro-2-deoxy-d-glucose (FDG-PET), single-photon emission computed tomography with technetium-99m hexamethylpropylene amine oxime (HMPAO-SPET) and magnetic resonance imaging (MRI) - in order to detect brain involvement in SLE. Thirty-seven SLE patients, aged 22-45 years, were divided into three groups. Group 1 (G1) consisted of ten patients with major neuropsychiatric manifestations; group 2 (G2) consisted of 15 patients with minor manifestations; and group 3 (G3) consisted of 12 patients without manifestations. FDG-PET findings were abnormal in 51% of patients: 90% of G1, 67% of G2 and 0% of G3 patients respectively. HMPAO-SPET findings were abnormal in 62% of patients: 100% of G1, 73% of G2 and 17% of G3 patients respectively. MRI findings were abnormal in 35% of patients: 70% of G1, 40% of G2 and 0% of G3 patients respectively. Grey matter was more commonly involved than white matter; 62% of patients presented with lesions in the cerebral cortex, 27% with lesions in the basal ganglion, 5% with lesions in the cerebellum, and 19% with lesions in white matter. No white matter lesions were found on FDG-PET or HMPAO-SPET. However, in 19% of patients, MRI demonstrated abnormally high signal lesions in white matter. Forty-three percent of cases had positive serum anticardiolipin antibodies (ACA). However, ACA was not related to FDG-PET, HMPAO-SPET or MRI findings. It may be concluding that HMPAO-SPET is a more sensitive tool for detecting brain involvement in SLE patients when compared with FDG-PET or MRI. However, MRI is necessary for detecting lesions in white matter. (orig.) With 3 figs., 2 tabs., 46 refs.

  4. A Novel Approach for Cancer Detection in MRI Mammogram Using Decision Tree Induction and BPN

    Directory of Open Access Journals (Sweden)

    S. Pitchumani Angayarkanni, V. Saravanan

    2011-02-01

    Full Text Available An intelligent computer-aided diagnosis system can be very helpful for radiologist indetecting and diagnosing micro calcifications patterns earlier and faster than typicalscreening programs. In this paper, we present a system based on fuzzy-C Meansclustering and feature extraction techniques using texture based segmentation andgenetic algorithm for detecting and diagnosing micro calcifications’ patterns in digitalmammograms. We have investigated and analyzed a number of feature extractiontechniques and found that a combination of three features, such as entropy,standard deviation, and number of pixels, is the best combination to distinguish abenign micro calcification pattern from one that is malignant. A fuzzy C Meanstechnique in conjunction with three features was used to detect a micro calcificationpattern and a neural network to classify it into benign/malignant. The system wasdeveloped on a Windows platform. It is an easy to use intelligent system that givesthe user options to diagnose, detect, enlarge, zoom, and measure distances of areasin digital mammograms. The present study focused on the investigation of theapplication of artificial intelligence and data mining techniques to the predictionmodels of breast cancer. The artificial neural network, decision tree, Fuzzy C Means,and genetic algorithm were used for the comparative studies and the accuracy andpositive predictive value of each algorithm were used as the evaluation indicators.699 records acquired from the breast cancer patients at the MIAS database, 9predictor variables, and 1 outcome variable were incorporated for the data analysisfollowed by the 10-fold cross-validation. The results revealed that the accuracies ofFuzzy C Means were 0.9534 (sensitivity 0.98716 and specificity 0.9582, thedecision tree model 0.9634 (sensitivity 0.98615, specificity 0.9305, the neuralnetwork model 0.96502 (sensitivity 0.98628, specificity 0.9473, the geneticalgorithm model 0.9878 (sensitivity 1, specificity 0.9802. The accuracy of thegenetic algorithm was significantly higher than the average predicted accuracy of0.9612. The predicted outcome of the Fuzzy C Means model was higher than that ofthe neural network model but no significant difference was observed. The averagepredicted accuracy of the decision tree model was 0.9635 which was the lowest of all4 predictive models. The standard deviation of the 10-fold cross-validation wasrather unreliable. The results showed that the genetic algorithm described in thepresent study was able to produce accurate results in the classification of breastcancer data and the classification rule identified was more acceptable andcomprehensible.

  5. MRI-detected skull-base invasion. Prognostic value and therapeutic implication in intensity-modulated radiotherapy treatment for nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    With advances in imaging and radiotherapy, the prognostic value of skull-base invasion in nasopharyngeal carcinoma (NPC) needs to be reassessed. We aimed to define a classification system and evaluate the prognostic value of the classification of magnetic resonance imaging (MRI)-detected skull-base invasion in NPC treated with intensity-modulated radiotherapy (IMRT). We retrospectively reviewed 749 patients who underwent MRI and were subsequently histologically diagnosed with nondisseminated NPC and treated with IMRT. MRI-detected skull-base invasion was not found to be an independent prognostic factor for overall survival (OS), distant metastasis-free survival (DMFS), local relapse-free survival (LRFS), or disease-free survival (DFS; p > 0.05 for all). Skull-base invasion was classified according to the incidence of each site (type I sites inside pharyngobasilar fascia and clivus vs. type II sites outside pharyngobasilar fascia). The 5-year OS, DMFS, LRFS, and DFS rates in the classification of skull-base invasion in NPC were 83 vs. 67 %, 85 vs.75 %, 95 vs. 88 %, and 76 vs. 62 %, respectively (p < 0.05 for all). Multivariate analysis indicated the classification of skull-base invasion was an independent prognostic factor. MRI-detected skull-base invasion is not an independent prognostic factor in patients with NPC treated with IMRT. However, classification according to the site of invasion has prognostic value. Therefore, patients with various subclassifications of stage T3 disease may receive treatment with different intensities; however, further studies are warranted to prove this. (orig.)

  6. Recent Progress in the Remote Detection of Vapours and Gaseous Pollutants.

    Science.gov (United States)

    Moffat, A. J.; And Others

    Work has been continuing on the correlation spectrometry techniques described at previous remote sensing symposiums. Advances in the techniques are described which enable accurate quantitative measurements of diffused atmospheric gases to be made using controlled light sources, accurate quantitative measurements of gas clouds relative to…

  7. Heart-induced movements in the thorax as detected by MRI

    CERN Document Server

    Solberg, Lars Erik; Fosse, Erik; Hol, Per Kristian

    2014-01-01

    In order to provide information for the use of radar in diagnostics a qualitative map of movements in the thorax has been obtained. This map was based on magnetic resonance image sequences of a human thorax during suspended respiration. The movements were measured using two distinct techniques. Segmentation provided measures of aorta dilatation and displacements, and image edge detection indicated other movements. The largest heart movements were found in the anterior and left regions of the heart with in-plane displacements on the order of 1 cm and which caused lung vessels displacements on the order of 2-3mm especially on the left side due to the heart ventricular. Mechanical coupling between the heart and aorta caused aorta displacements and shape distortions. Despite this coupling, aorta dilatations most likely reflected blood pressure variations.

  8. Positive contrast technique for the detection and quantification of superparamagnetic iron oxide nanoparticles in MRI.

    Science.gov (United States)

    Zhao, Qun; Langley, Jason; Lee, Sunbok; Liu, Wei

    2011-06-01

    In vivo detection and quantification of cells labeled with superparamagnetic iron oxide (SPIO) nanoparticles has been attracting increasing attention. In particular, positive contrast methods, such as susceptibility gradient mapping (SGM) and phase gradient mapping (PGM), have been proposed for the improved detection of SPIO nanoparticles. In this study, a different implementation of the PGM method is introduced; it calculates the phase gradient in the image space using a fast Fourier transform without the need for phase unwrapping. We first compared positive contrast generation between the PGM and SGM methods, which estimates the susceptibility gradient in k space through echo shift measurements. Next, PGM was applied to quantify SPIO concentrations by fitting the resulting phase gradient maps to those of a theoretical model. MR experiments were conducted using a 3-T magnet scanner to acquire two datasets: the first was acquired from a gelatin phantom with three SPIO-doped vials of different concentrations, and the second was obtained in vivo from a nude rat with SPIO-labeled C6 glioma cells implanted in the flanks. The sensitivity of the PGM and SGM methods was compared using various factors, including different SPIO concentrations, TEs and signal-to-noise ratios. Based on the theoretical model of an infinite cylinder, the results demonstrated that, without loss of spatial resolution, the PGM method presents positive contrast maps with a higher sensitivity than SGM at medium and low SPIO concentrations, whereas SGM is more sensitive than PGM at longer TEs. The quantification of SPIO concentrations using the phantom dataset was also reported. On the basis of the same infinite cylinder model, it was shown that the PGM method provides an accurate estimation of SPIO concentration. PMID:20931569

  9. MRI in osteochondrosis dissecans

    International Nuclear Information System (INIS)

    The osseous manifestations of osteochondrosis dissecans are well demonstrated by conventional and computerised tomography. Beyond that, magnetic resonance imaging (MRI) is effective in evaluating the vitality and loosening of an osseous dissecate. Subchondral cavities and cartilaginous defects are detected with high acccuracy. Further, MRI seems to be a useful method in childhood to differentiate a variant irregularity of the osseous articular surface from definite osteochondrosis dissecans. (orig.)

  10. MRI Stealth” robot for prostate interventions

    OpenAIRE

    Stoianovici, Dan; SONG, DANNY; Petrisor, Doru; Ursu, Daniel; Mazilu, Dumitru; MUTENER, MICHAEL; SCHAR, MICHAEL; PATRICIU, ALEXANDRU

    2007-01-01

    The paper reports an important achievement in MRI instrumentation, a pneumatic, fully actuated robot located within the scanner alongside the patient and operating under remote control based on the images. Previous MRI robots commonly used piezoelectric actuation limiting their compatibility. Pneumatics is an ideal choice for MRI compatibility because it is decoupled from electromagnetism, but pneumatic actuators were hardly controllable. This achievement was possible due to a recent technolo...

  11. High-resolution anatomy of the human brain stem using 7-T MRI: improved detection of inner structures and nerves?

    Energy Technology Data Exchange (ETDEWEB)

    Gizewski, Elke R. [Medical University Innsbruck, Department of Neuroradiology, Innsbruck (Austria); Maderwald, Stefan [University Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); Linn, Jennifer; Bochmann, Katja [LMU Munich, Department of Neuroradiology, Munich (Germany); Dassinger, Benjamin [Medical University Innsbruck, Department of Neuroradiology, Innsbruck (Austria); Justus-Liebig-University Giessen, Department of Neuroradiology, Giessen (Germany); Forsting, Michael [University Hospital, University Duisburg-Essen, Departments of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Ladd, Mark E. [University Duisburg-Essen, Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen (Germany); University Hospital, University Duisburg-Essen, Departments of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany)

    2014-03-15

    The purpose of this paper is to assess the value of 7 Tesla (7 T) MRI for the depiction of brain stem and cranial nerve (CN) anatomy. Six volunteers were examined at 7 T using high-resolution SWI, MPRAGE, MP2RAGE, 3D SPACE T2, T2, and PD images to establish scanning parameters targeted at optimizing spatial resolution. Direct comparisons between 3 and 7 T were performed in two additional subjects using the finalized sequences (3 T: T2, PD, MPRAGE, SWAN; 7 T: 3D T2, MPRAGE, SWI, MP2RAGE). Artifacts and the depiction of structures were evaluated by two neuroradiologists using a standardized score sheet. Sequences could be established for high-resolution 7 T imaging even in caudal cranial areas. High in-plane resolution T2, PD, and SWI images provided depiction of inner brain stem structures such as pons fibers, raphe, reticular formation, nerve roots, and periaqueductal gray. MPRAGE and MP2RAGE provided clear depiction of the CNs. 3D T2 images improved depiction of inner brain structure in comparison to T2 images at 3 T. Although the 7-T SWI sequence provided improved contrast to some inner structures, extended areas were influenced by artifacts due to image disturbances from susceptibility differences. Seven-tesla imaging of basal brain areas is feasible and might have significant impact on detection and diagnosis in patients with specific diseases, e.g., trigeminal pain related to affection of the nerve root. Some inner brain stem structures can be depicted at 3 T, but certain sequences at 7 T, in particular 3D SPACE T2, are superior in producing anatomical in vivo images of deep brain stem structures. (orig.)

  12. High-resolution anatomy of the human brain stem using 7-T MRI: improved detection of inner structures and nerves?

    International Nuclear Information System (INIS)

    The purpose of this paper is to assess the value of 7 Tesla (7 T) MRI for the depiction of brain stem and cranial nerve (CN) anatomy. Six volunteers were examined at 7 T using high-resolution SWI, MPRAGE, MP2RAGE, 3D SPACE T2, T2, and PD images to establish scanning parameters targeted at optimizing spatial resolution. Direct comparisons between 3 and 7 T were performed in two additional subjects using the finalized sequences (3 T: T2, PD, MPRAGE, SWAN; 7 T: 3D T2, MPRAGE, SWI, MP2RAGE). Artifacts and the depiction of structures were evaluated by two neuroradiologists using a standardized score sheet. Sequences could be established for high-resolution 7 T imaging even in caudal cranial areas. High in-plane resolution T2, PD, and SWI images provided depiction of inner brain stem structures such as pons fibers, raphe, reticular formation, nerve roots, and periaqueductal gray. MPRAGE and MP2RAGE provided clear depiction of the CNs. 3D T2 images improved depiction of inner brain structure in comparison to T2 images at 3 T. Although the 7-T SWI sequence provided improved contrast to some inner structures, extended areas were influenced by artifacts due to image disturbances from susceptibility differences. Seven-tesla imaging of basal brain areas is feasible and might have significant impact on detection and diagnosis in patients with specific diseases, e.g., trigeminal pain related to affection of the nerve root. Some inner brain stem structures can be depicted at 3 T, but certain sequences at 7 T, in particular 3D SPACE T2, are superior in producing anatomical in vivo images of deep brain stem structures. (orig.)

  13. Frequency Domain Detection with Nearest Neighbor Clustering to Detect Dynamically Triggered Remote Small Earthquakes within the Footprint of the EarthScope USArray Transportable Array

    Science.gov (United States)

    Kilb, D. L.; Linville, L. M.; Pankow, K. L.

    2014-12-01

    To better understand earthquake source processes involved in dynamically triggering remote aftershocks, we design and test an automated algorithm to detect far-field aftershocks from two large earthquakes. Our goal is to create a method that is tractable for large datasets, ensures robust catalogs, and delivers lower magnitude of completeness than current catalogs. We use data recorded by the EarthScope's USArray Transportable Array (TA), which has a uniform 70km grid spacing and large spatial coverage. We test 3-hours of data following the 12 September 2007 Sumatra M8.5 earthquake and the 07 November 2012 M7.4 Guatemala earthquake, when the TA network was on the west-coast and east-coast of the contiguous US, respectively. This allows exploration of a broad range of tectonic environments and regions of both small tectonic earthquakes (2007 data) and significant extraction sector activity, such as mine blasts (2012 data). The main steps in our data processing include: (1) A frequency domain detection algorithm to identify signals above the noise floor in the 4-12 Hz range to create a detection catalog. (2) Iteratively implementing a nearest-neighbor technique to remove detection outliers from the catalog. (3) Partitioning the detections into high density clusters. (4) Building an earthquake catalog where, for each cluster, we assume the station location that first recorded the seismic energy is a good proxy for the location of the local earthquake and this signal's arrival time is a good proxy for the time of the earthquake. Our results identify 7 and 9 events in the 2007 and 2012 data, respectively, which is a significant increase over the 3 and 2 earthquakes listed in the ANF catalog during the same time periods. This method is ideal for identifying the signature of small earthquakes within the wavetrain of large remote mainshocks recorded by the TA network.

  14. Laser-induced fluorescence of green plants. I - A technique for the remote detection of plant stress and species differentiation

    Science.gov (United States)

    Chappelle, E. W.; Wood, F. M., Jr.; Mcmurtrey, J. E., III; Newcomb, W. W.

    1984-01-01

    The laser-induced fluorescence (LIF) of green plants was evaluated as a means of remotely detecting plant stress and determining plant type. Corn and soybeans were used as representatives of monocots and dicots, respectively, in these studies. The fluorescence spectra of several plant pigments was excited with a nitrogen laser emitting at 337 nm. Intact leaves from corn and soybeans also fluoresced using the nitrogen laser. The two plant species exhibited fluorescence spectra which had three maxima in common at 440, 690, and 740 nm. However, the relative intensities of these maxima were distinctly different for the two species. Soybeans had an additional slight maxima at 525 nm. Potassium deficiency in corn caused an increase in fluorescence at 690 and 740 nm. Simulated water stress in soybeans resulted in increased fluorescence at 440, 525, 690, and 740 nm. The inhibition of photosynthesis in soybeans by 3-(3-4-dichlorophenyl)-1-1-dimethyl urea (DCMU) gave incresed fluorescence primarily at 690 and 740 nm. Chlorosis as occurring in senescent soybean leaves caused a decrease in fluorescence at 690 and 740 nm. These studies indicate that LIF measurements of plants offer the potential for remotely detecting certain types of stress condition and also for differentiating plant species.

  15. Automatic Detection and Recognition of Man-Made Objects in High Resolution Remote Sensing Images Using Hierarchical Semantic Graph Model

    Science.gov (United States)

    Sun, X.; Thiele, A.; Hinz, S.; Fu, K.

    2013-05-01

    In this paper, we propose a hierarchical semantic graph model to detect and recognize man-made objects in high resolution remote sensing images automatically. Following the idea of part-based methods, our model builds a hierarchical possibility framework to explore both the appearance information and semantic relationships between objects and background. This multi-levels structure is promising to enable a more comprehensive understanding of natural scenes. After training local classifiers to calculate parts properties, we use belief propagation to transmit messages quantitatively, which could enhance the utilization of spatial constrains existed in images. Besides, discriminative learning and generative learning are combined interleavely in the inference procedure, to improve the training error and recognition efficiency. The experimental results demonstrate that this method is able to detect manmade objects in complicated surroundings with satisfactory precision and robustness.

  16. Integrated remote sensing techniques for the detection of buried archaeological adobe structures: preliminary results in Cahuachi (Peru

    Directory of Open Access Journals (Sweden)

    N. Masini

    2008-11-01

    Full Text Available This paper is focused on the jointly use of satellite Quickbird (QB images and Ground Probing Radar (GPR for assessing their capability in the detection of archaeological adobe structures (sun-dried earth material. Such detection is particularly complex. due to the low contrast generally existing between the archaeological features and the background. Two significant test areas were investigated in the Ceremonial Centre of Cahuachi (in the Nasca territory, Southern Peru dating back to 6th century BC to 4th century AD.

    Our results showed that both satellite and GPR data provided valuable indications for unearthing precious ancient remains. Our preliminary analyses pointed out that the integrated use of non destructive remote sensing techniques has high potentiality for its important scientific implications and for its significant contributions to cultural resource management.

  17. New technological developments for the remote detection of atmospheric hydroxyl radicals

    Science.gov (United States)

    Mcdermid, I. S.; Laudenslager, J. B.; Pacala, T. J.

    1983-01-01

    New developments in the areas of narrowband tunable excimer lasers, high-resolution high-rejection optical filters, and wavelength measurement devices are considered for application to the remote sensing of atmospheric hydroxyl radicals. The conclusion is that an increase in the SNR of 10,000 could readily be gained through the use of these new devices. Also, considerable reductions in size and electrical energy consumption could be realized.

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

    OpenAIRE

    Babykalpana, Y.; k. Thanushkodi

    2010-01-01

    Maps are used to describe far-off places . It is an aid for navigation and military strategies. Mapping of the lands are important and the mapping work is based on (i). Natural resource management & development (ii). Information technology ,(iii). Environmental development ,(iv). Facility management and (v). e-governance. The Landuse / Landcover system espoused by almost all Organisations and scientists, engineers and remote sensing community who are involved in mapping of e...

  19. Detection of Usefullness of Integrating Remotely Sensed Data (Landsat TM) with GIS

    OpenAIRE

    Abdul Halim, H.; Jumaat, H. A.; Juhari, M. A.; Sahibin, A. R.; Hamid, Hafiza A.; Ramlan Bin Omar; Gire Kibe Gopir; Jumat Salimon; Barzani Qasim

    2006-01-01

    A study integrating remote sensing and Geographical Information System (GIS) was carried out in the Kuala Terengganu district, Terengganu, Malaysia to map and determine the land use change as a result of development pressure in the area. Two sets of Landsat Thematic Mapper (TM) dated 31 July 1988 and 14 July 2002, at scale 1: 150 000 were acquired. Land use classes were interpreted from these images and the resultant maps were checked in the field to determine ground truth and mapping accurac...

  20. Use of Remote Sensing to Detect Soybean Cyst Nematode-Induced Plant Stress

    OpenAIRE

    Nutter, F. W.; Tylka, G. L.; Guan, J.; Moreira, A. J. D.; Marett, C. C.; Rosburg, T. R.; Basart, J. P.; Chong, C. S.

    2002-01-01

    Integrating remote sensing and geographic information systems (GIS) technologies offers tremendous opportunities for farmers to more cost effectively manage the causes of crop stress. Initial soybean cyst nematode (SCN) population densities from 995 2-×-3-m quadrats were obtained from a soybean field near Ames, Iowa, in 2000. The percentage of sunlight reflected from each quadrat was measured weekly using a multispectral radiometer beginning in mid-May and continuing through mid-September. A...

  1. Detection of prostate cancer by real-time MR/ultrasound fusion-guided biopsy. 3T MRI and state of the art sonography

    International Nuclear Information System (INIS)

    Purpose: Multiparametric MRI of the prostate is a noninvasive diagnostic method with high sensitivity and specificity for prostate cancer. The aim of this study is to evaluate whether prostate cancer detection rates of transrectal ultrasound (TRUS)-guided biopsy may be improved by an image fusion of state-of-the-art ultrasound (CEUS, elastography) and MR (T2w, DWI) imaging. Materials and Methods: 32 consecutive patients with a history of elevated PSA levels and at least one negative TRUS-guided biopsy with clinical indication for a systematic re-biopsy underwent multiparametric 3 T MRI without endorectal coil. MR data (T2w) were uploaded to a modern sonography system and image fusion was performed in real-time mode during biopsy. B-mode, Doppler, elastography and CEUS imaging were applied to characterize suspicious lesions detected by MRI. Targeted biopsies were performed in MR/US fusion mode followed by a systematic standard TRUS-guided biopsy. Detection rates for both methods were calculated and compared using the Chi2-test. Results: Patient age was not significantly different in patients with and without histologically confirmed prostate cancer (65.2 ± 8.0 and 64.1 ± 7.3 age [p = 0.93]). The PSA value was significantly higher in patients with prostate cancer (15.5 ± 9.3 ng/ml) compared to patients without cancer (PSA 10.4 ± 9.6 ng/ml; p = 0.02). The proportion of histologically confirmed cancers in the study group (n = 32) of the MR/US fusion biopsy p (n = 32) of the MR/US fusion biopsy (11/12; 34.4 %) was significantly higher (p = 0.01) in comparison to the TRUS systematic biopsy (6/12; 18.8 %). Conclusion: Real-time MR/US image fusion may enhance cancer detection rates of TRUS-guided biopsies and should therefore be studied in further larger studies. (orig.)

  2. Breath-hold T2-weighted MRI of the liver at 3 T using the BLADE technique: impact upon image quality and lesion detection

    International Nuclear Information System (INIS)

    Aim: To compare image quality and lesion detection in the liver using magnetic resonance imaging (MRI) at 3 T between T2-weighted imaging using a standard rectilinear k-space trajectory (standard T2WI) and using the BLADE technique (BLADE-T2WI), a technique that employs periodically rotated overlapping parallel lines with enhanced reconstruction for motion correction. Materials and methods: Twenty-eight consecutive patients who underwent MRI examination of the liver at 3 T including standard T2WI and BLADE-T2WI, both performed using multiple breath-holds, comprised the study cohort. Images were reviewed in consensus by two radiologists during separate sessions for a number of measures regarding artefacts and image quality. These two readers also assessed the two image sets for the presence of liver lesions and measured liver-to-lesion contrast. Binary logistic regression for correlated data was used to compare the sequences in terms of sensitivity and positive predictive value (PPV) for lesion detection. Results: BLADE-T2WI received significantly higher scores than did standard T2WI for in-plane respiratory motion (p = 0.0195), other ghosting artefacts (p 1-inhomogeneity artefact with BLADE-T2WI (p = 0.0571). There was no differenE-T2WI (p = 0.0571). There was no difference in through-plane respiratory motion (p = 0.6836). BLADE-T2WI demonstrated a significant improvement in PPV for lesion detection (p = 0.0129) as well as in liver-to-lesion contrast (p = 0.0054). There was no difference regarding lesion sensitivity (p = 1.0). Conclusions: Use of the BLADE technique for T2-weighted MRI of the liver at 3 T may lead to a significant improvement in image artefacts and improved PPV for lesion detection.

  3. Ultra-sensitive molecular MRI of cerebrovascular cell activation enables early detection of chronic central nervous system disorders

    International Nuclear Information System (INIS)

    Since endothelial cells can be targeted by large contrast-carrying particles, molecular imaging of cerebrovascular cell activation is highly promising to evaluate the underlying inflammation of the central nervous system (CNS). In this study, we aimed to demonstrate that molecular magnetic resonance imaging (MRI) of cerebrovascular cell activation can reveal CNS disorders in the absence of visible lesions and symptoms. To this aim, we optimized contrast carrying particles targeting vascular cell adhesion molecule-1 and MRI protocols through both in vitro and in vivo experiments. Although, pre-contrast MRI images failed to reveal the ongoing pathology, contrast-enhanced MRI revealed hypoperfusion-triggered CNS injury in vascular dementia, unmasked amyloid-induced cerebrovascular activation in Alzheimer's disease and allowed monitoring of disease activity during experimental autoimmune encephalomyelitis. Moreover, contrast-enhanced MRI revealed the cerebrovascular cell activation associated with known risk factors of CNS disorders such as peripheral inflammation, ethanol consumption, hyperglycemia and aging. By providing a dramatically higher sensitivity than previously reported methods and molecular contrast agents, the technology described in the present study opens new avenues of investigation in the field of neuro-inflammation. (authors)

  4. Mammographycally occult high grade ductal carcinoma in situ (DCIS) as second primary breast cancer, detected with MRI: a case report

    International Nuclear Information System (INIS)

    Contralateral breast cancer (CLB) is the most common second primary breast cancer in patients diagnosed with breast cancer. The majority of patients harbouring CLB tumours develop the invasive disease. Almost all invasive carcinomas are believed to begin as ductal carcinoma in situ (DCIS) lesions. The sensitivity of MRI for DCIS is much higher than that of mammography. We report the case of a woman who was treated with breast conserving therapy 10 years ago. At that time the invasive medullary carcinoma was diagnosed in the left breast. Ten years later mammographically occult DCIS was diagnosed with MRI-guided core biopsy in contralateral breast. There might be a potential role of MRI screening as part of an annual follow-up for patients diagnosed with breast cancer

  5. Hyperspectral Remote Sensing and Groundwater Simulation for Detecting Riparian Wetness Gradients

    Science.gov (United States)

    Yirdaw-Zeleke, S.; Batelaan, O.; Snelgrove, K. R.

    2004-12-01

    Groundwater is a precious resource of limited extent. The importance of determining and describing hydrological groundwater flow systems is one of the most important aspects for the management and development of ecological values, especially in valleys of river basin. Knowledge about discharge and recharge zones forms the basis for sound, quantitatively and qualitatively, water management of groundwater flow systems. Determination of discharge-recharge zones using hydrological models needs a large volume of data from various sources. Integrated Hyperspectral remote sensed data and GIS can provide an effective tool in characterizing groundwater flow systems and discharge-recharge relationships. In the present study, an integrated hyperspectral remote sensing and GIS based methodology is developed and tested for the evaluation of groundwater flow system of Doode Bemde wetland in the valley of the Dijle River, Belgium. There are three components of the study; (a) Development of groundwater model using the three dimensional groundwater model, MODFLOW, (b) Extraction of information about the groundwater flow system from CASI-SWIR hyperspectral data using ENVI 3.5 software and, (c) Comparison of each individual CASI-SWIR band with the simulated groundwater depth and discharge-recharge zones. The simulated discharge areas are verified by hyperspectral remote sensed data. The first principle component is found to be the best for identification of recharge zones in study area. An area cross-tabulation two-dimensional table that summarizes the areal overlap of all the possible combination of the two input maps (from the hydrological model and the image) or an error matrix is applied for expressing classification accuracy. The correlation values between 0.6 and 0.65 are observed on the wavelength domain from 0.90 to 1.30µm and on the first principle component with the groundwater depth. These bands are among the best for use as a source of information for shallow groundwater depth (up to 1.5m) for natural grasslands.

  6. Remote detection of human toxicants in real time using a human-optimized, bioluminescent bacterial luciferase gene cassette bioreporter

    Science.gov (United States)

    Close, Dan; Webb, James; Ripp, Steven; Patterson, Stacey; Sayler, Gary

    2012-06-01

    Traditionally, human toxicant bioavailability screening has been forced to proceed in either a high throughput fashion using prokaryotic or lower eukaryotic targets with minimal applicability to humans, or in a more expensive, lower throughput manner that uses fluorescent or bioluminescent human cells to directly provide human bioavailability data. While these efforts are often sufficient for basic scientific research, they prevent the rapid and remote identification of potentially toxic chemicals required for modern biosecurity applications. To merge the advantages of high throughput, low cost screening regimens with the direct bioavailability assessment of human cell line use, we re-engineered the bioluminescent bacterial luciferase gene cassette to function autonomously (without exogenous stimulation) within human cells. Optimized cassette expression provides for fully endogenous bioluminescent production, allowing continuous, real time monitoring of the bioavailability and toxicology of various compounds in an automated fashion. To access the functionality of this system, two sets of bioluminescent human cells were developed. The first was programed to suspend bioluminescent production upon toxicological challenge to mimic the non-specific detection of a toxicant. The second induced bioluminescence upon detection of a specific compound to demonstrate autonomous remote target identification. These cells were capable of responding to ?M concentrations of the toxicant n-decanal, and allowed for continuous monitoring of cellular health throughout the treatment process. Induced bioluminescence was generated through treatment with doxycycline and was detectable upon dosage at a 100 ng/ml concentration. These results demonstrate that leveraging autonomous bioluminescence allows for low-cost, high throughput direct assessment of toxicant bioavailability.

  7. Review of the embryologic development of the pituitary gland and report of a case of hypophyseal duplication detected by MRI

    International Nuclear Information System (INIS)

    We describe the clinical manifestations, associated abnormalities, MRI appearances and pathologic significance of a case of hypophyseal duplication. A 16-year-old girl presented with delayed sexual development and history of midline craniofacial anomalies. MRI revealed paired infundibula extending inferiorly to two small pituitary glands, a midline hypothalamic mass, and a midline cleft in the basisphenoid. Twelve cases of pituitary duplication have previously been described. The suggested pathogenesis is duplication of the prechordal plate and anterior end of the notochord during early embryologic development. (orig.)

  8. Combined molecular MRI and immuno-spin-trapping for in vivo detection of free radicals in orthotopic mouse GL261 gliomas.

    Science.gov (United States)

    Towner, Rheal A; Smith, Nataliya; Saunders, Debra; De Souza, Patricia Coutinho; Henry, Leah; Lupu, Florea; Silasi-Mansat, Robert; Ehrenshaft, Marilyn; Mason, Ronald P; Gomez-Mejiba, Sandra E; Ramirez, Dario C

    2013-12-01

    Free radicals play a major role in gliomas. By combining immuno-spin-trapping (IST) and molecular magnetic resonance imaging (mMRI), in vivo levels of free radicals were detected within mice bearing orthotopic GL261 gliomas. The nitrone spin trap DMPO (5,5-dimethyl pyrroline N-oxide) was administered prior to injection of an anti-DMPO probe (anti-DMPO antibody covalently bound to a bovine serum albumin (BSA)-Gd (gadolinium)-DTPA (diethylene triamine penta acetic acid)-biotin MRI contrast agent) to trap tumor-associated free radicals. mMRI detected the presence of anti-DMPO adducts by either a significant sustained increase (p<0.001) in MR signal intensity or a significant decrease (p<0.001) in T1 relaxation, measured as %T1 change. In vitro assessment of the anti-DMPO probe indicated a significant decrease (p<0.0001) in T1 relaxation in GL261 cells that were oxidatively stressed with hydrogen peroxide, compared to controls. The biotin moiety of the anti-DMPO probe was targeted with fluorescently-labeled streptavidin to locate the anti-DMPO probe in excised brain tissues. As a negative control a non-specific IgG antibody covalently bound to the albumin-Gd-DTPA-biotin construct was used. DMPO adducts were also confirmed in tumor tissue from animals administered DMPO, compared to non-tumor brain tissue. GL261 gliomas were found to have significantly increased malondialdehyde (MDA) protein adducts (p<0.001) and 3-nitrotyrosine (3-NT) (p<0.05) compared to normal mouse brain tissue, indicating increased oxidized lipids and proteins, respectively. Co-localization of the anti-DMPO probe with either 3-NT or 4-hydroxynonenal was also observed. This is the first report regarding the detection of in vivo levels of free radicals from a glioma model. PMID:23959048

  9. Environmental data analysis and remote sensing for early detection of dengue and malaria

    Science.gov (United States)

    Rahman, Md Z.; Roytman, Leonid; Kadik, Abdelhamid; Rosy, Dilara A.

    2014-06-01

    Malaria and dengue fever are the two most common mosquito-transmitted diseases, leading to millions of serious illnesses and deaths each year. Because the mosquito vectors are sensitive to environmental conditions such as temperature, precipitation, and humidity, it is possible to map areas currently or imminently at high risk for disease outbreaks using satellite remote sensing. In this paper we propose the development of an operational geospatial system for malaria and dengue fever early warning; this can be done by bringing together geographic information system (GIS) tools, artificial neural networks (ANN) for efficient pattern recognition, the best available ground-based epidemiological and vector ecology data, and current satellite remote sensing capabilities. We use Vegetation Health Indices (VHI) derived from visible and infrared radiances measured by satellite-mounted Advanced Very High Resolution Radiometers (AVHRR) and available weekly at 4-km resolution as one predictor of malaria and dengue fever risk in Bangladesh. As a study area, we focus on Bangladesh where malaria and dengue fever are serious public health threats. The technology developed will, however, be largely portable to other countries in the world and applicable to other disease threats. A malaria and dengue fever early warning system will be a boon to international public health, enabling resources to be focused where they will do the most good for stopping pandemics, and will be an invaluable decision support tool for national security assessment and potential troop deployment in regions susceptible to disease outbreaks.

  10. Clinical value of periventricular low-intensity areas detected by fluid attenuated inversion recovery (FLAIR). Relationships between perinatal vital parameter and neonatal MRI

    International Nuclear Information System (INIS)

    A follow-up study was performed to assess the correlation among the incidence of periventricular low intensities (PVLI) on MRI (magnetic resonance imaging) FLAIR (fluid attenuated inversion recovery) imaging, clinical evidence of perinatal insults that may cause white matter damage, and the outcome of the infants. We evaluated periventricular white matter lesions of 329 neonates whose MRI were obtained before two months corrected age. The detective rate of periventricular abnormalities on FLAIR imaging was significantly higher than that of T1-T2 weighted imaging. The most typical lesion detected on FLAIR imaging was periventricular low intensities (PVLI), frequently observed in the neonates with a history of preterm labour, very low birth weight, birth asphyxia and severe respiratory failure. Although we could not characterize the risk factors of PVLI, the incidence of PVLI had a strong correlation with the scores of motor and developmental tests at 12 and 36-months corrected age. In conclusion, FLAIR imaging, detecting the border zone damage of white matter, would be a strong tool to pick out neonates at high risk of neurological disturbances from those without clinical evidence of neurological insults in the neonatal period. (author)

  11. Enhanced multi-protocol analysis via intelligent supervised embedding (EMPrAvISE): detecting prostate cancer on multi-parametric MRI

    Science.gov (United States)

    Viswanath, Satish; Bloch, B. Nicholas; Chappelow, Jonathan; Patel, Pratik; Rofsky, Neil; Lenkinski, Robert; Genega, Elizabeth; Madabhushi, Anant

    2011-03-01

    Currently, there is significant interest in developing methods for quantitative integration of multi-parametric (structural, functional) imaging data with the objective of building automated meta-classifiers to improve disease detection, diagnosis, and prognosis. Such techniques are required to address the differences in dimensionalities and scales of individual protocols, while deriving an integrated multi-parametric data representation which best captures all disease-pertinent information available. In this paper, we present a scheme called Enhanced Multi-Protocol Analysis via Intelligent Supervised Embedding (EMPrAvISE); a powerful, generalizable framework applicable to a variety of domains for multi-parametric data representation and fusion. Our scheme utilizes an ensemble of embeddings (via dimensionality reduction, DR); thereby exploiting the variance amongst multiple uncorrelated embeddings in a manner similar to ensemble classifier schemes (e.g. Bagging, Boosting). We apply this framework to the problem of prostate cancer (CaP) detection on 12 3 Tesla pre-operative in vivo multi-parametric (T2-weighted, Dynamic Contrast Enhanced, and Diffusion-weighted) magnetic resonance imaging (MRI) studies, in turn comprising a total of 39 2D planar MR images. We first align the different imaging protocols via automated image registration, followed by quantification of image attributes from individual protocols. Multiple embeddings are generated from the resultant high-dimensional feature space which are then combined intelligently to yield a single stable solution. Our scheme is employed in conjunction with graph embedding (for DR) and probabilistic boosting trees (PBTs) to detect CaP on multi-parametric MRI. Finally, a probabilistic pairwise Markov Random Field algorithm is used to apply spatial constraints to the result of the PBT classifier, yielding a per-voxel classification of CaP presence. Per-voxel evaluation of detection results against ground truth for CaP extent on MRI (obtained by spatially registering pre-operative MRI with available whole-mount histological specimens) reveals that EMPrAvISE yields a statistically significant improvement (AUC=0.77) over classifiers constructed from individual protocols (AUC=0.62, 0.62, 0.65, for T2w, DCE, DWI respectively) as well as one trained using multi-parametric feature concatenation (AUC=0.67).

  12. Enhanced Multi-Protocol Analysis via Intelligent Supervised Embedding (EMPrAvISE): Detecting Prostate Cancer on Multi-Parametric MRI

    Science.gov (United States)

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

    2014-01-01

    Currently, there is significant interest in developing methods for quantitative integration of multi-parametric (structural, functional) imaging data with the objective of building automated meta-classifiers to improve disease detection, diagnosis, and prognosis. Such techniques are required to address the differences in dimensionalities and scales of individual protocols, while deriving an integrated multi-parametric data representation which best captures all disease-pertinent information available. In this paper, we present a scheme called Enhanced Multi-Protocol Analysis via Intelligent Supervised Embedding (EMPrAvISE); a powerful, generalizable framework applicable to a variety of domains for multi-parametric data representation and fusion. Our scheme utilizes an ensemble of embeddings (via dimensionality reduction, DR); thereby exploiting the variance amongst multiple uncorrelated embeddings in a manner similar to ensemble classifier schemes (e.g. Bagging, Boosting). We apply this framework to the problem of prostate cancer (CaP) detection on 12 3 Tesla pre-operative in vivo multi-parametric (T2-weighted, Dynamic Contrast Enhanced, and Diffusion-weighted) magnetic resonance imaging (MRI) studies, in turn comprising a total of 39 2D planar MR images. We first align the different imaging protocols via automated image registration, followed by quantification of image attributes from individual protocols. Multiple embeddings are generated from the resultant high-dimensional feature space which are then combined intelligently to yield a single stable solution. Our scheme is employed in conjunction with graph embedding (for DR) and probabilistic boosting trees (PBTs) to detect CaP on multi-parametric MRI. Finally, a probabilistic pairwise Markov Random Field algorithm is used to apply spatial constraints to the result of the PBT classifier, yielding a per-voxel classification of CaP presence. Per-voxel evaluation of detection results against ground truth for CaP extent on MRI (obtained by spatially registering pre-operative MRI with available whole-mount histological specimens) reveals that EMPrAvISE yields a statistically significant improvement (AUC=0.77) over classifiers constructed from individual protocols (AUC=0.62, 0.62, 0.65, for T2w, DCE, DWI respectively) as well as one trained using multi-parametric feature concatenation (AUC=0.67). PMID:25301991

  13. Evaluation of Different Change Detection Techniques in Forestry for Improvement of Spatial Objects Extraction Algorithms by Very High Resolution Remote Sensing Digital Imagery

    Science.gov (United States)

    Amiri, N.

    2013-09-01

    Earth observations which are being useable by spatial analysis ability play an important role in detecting, management and solving environmental problems such as climate changes, deforestation, disasters, land use, water resource and carbon cycle. Remote sensing technology in combination with geospatial information system (GIS) can render reliable information on vegetation cover. Satellite Remote sensed data and GIS for land cover/use with its changes is a key to many diverse applications such as Forestry. Change detection can be defined as the process of identifying differences in the state of an object or phenomenon by observing it at different times. The analysis of the spatial extent and temporal change of vegetation cover (Forest) by using remotely sensed data is critically importance to natural resource management sciences. The main aim of this review paper is to go through the different change detection methods and algorithms based on very high resolution remote sensing imagery data, evaluate the quality of the spatial individual crown cover extraction in forests with high density, analyse, compare the results by optimized performance of control data for the same objects to provide the improvement in technique for detection and improve the mathematical sides of the change detection algorithms for high dense forests regions with different boundaries.

  14. The possibility of using remote sensing technology of lidar for monitoring ecosystem health by detecting habitat condition

    Science.gov (United States)

    Huseyinoglu, M. F.; Salaeva, Z.; Secgin, A.; Allakhverdiev, S. R.; Allakhverdiev, K. R.

    2012-01-01

    Since the emergence of laser and henceforth laser remote sensing in the 1960's, lidar (light detecting and ranging) technology has became a significant tool for the detection of various phenomena like wind direction and intensity, atmospheric temperature, urban and rural topography, forest fires, ocean planktonic development, and detection of various constituants such as tropospheric aerosols, stratospheric ozone, trace chemicals and etc. In 2009, a homemade multiwavelength Raman aerosol lidar (named MRC K09) was designed, developed and installed in the Scientific and Technological Research Council of Turkey (TUBITAK) Marmara Research Center (MRC), and since 21 February 2011, it has been accepted to EARLINET (European Aerosol Research Lidar Network). Since 2009, aerosol spatio-temporal distribution and microphysical properties have been investigated in the extremely industrialized vicinity [1,2]. MRC K09 lidar uses a Quantel Brilliant B Nd:YAG laser (1064 nm) with the second and third optical harmonics at 532 and 355 nm, and a homemade Newtonian 40 cm aperture 120 cm focal length telescope. It has 7 channel spectrum analyzer detecting: parallel and perpendicular polarizations at 355 nm, elastic signals at 532 and 1064 nm, Raman signal of molecular nitrogen at 387 nm and Raman signal of water vapor at 408 nm (excited with 355 laser line), and Raman signal for molecular nitrogen at 608 nm (excited with 532 nm laser line). In Spring 2010, preliminary applications for the determination of forest tree species and of forest health in the Black Sea Area using an aeroborne lidar in collaboration with Bartin University, Bartin, Turkey have been made. In early 2011, a fluorescence module utilizing a Princeton Instruments PI-MAX3 1024x256 resolution CCD camera with a Princeton Instruments Acton SP 2500 0.500 m Imaging Triple Grating Monochromator/Spectograph was connected to the MRC K09 lidar system, and the first remote measurements of chlorophyll from different types of trees were made. Figure 1 demonstrates the results of these measurements, which must be considered as preliminary and in the future, the measurements can be carried out by the lidar mounted on an aircraft to cover large spatial areas. One of the most important reasons for biodiversity loss, habitat loss and fragmentation can be monitored in large areas by aeroborne lidars and therefore the extent of the situation can be accessed precisely, faster and more efficiently. This paper aims to give a brief overview to show the possibility of detecting the detailed situations of the habitats on terrain surfaces using lidar technology by summarizing the successful examples which have been realized thus far in different types of ecosystems like savannas, forest and grasslands.

  15. Detection and Volume Estimation of Large Landslides by Using Multi-temporal Remote Sensing Data

    Science.gov (United States)

    Hsieh, Yu-chung; Hou, Chin-Shyong; Chan, Yu-Chang; Hu, Jyr-Ching; Fei, Li-Yuan; Chen, Hung-Jen; Chiu, Cheng-Lung

    2014-05-01

    Large landslides are frequently triggered by strong earthquakes and heavy rainfalls in the mountainous areas of Taiwan. The heavy rainfall brought by the Typhoon Morakot has triggered a large amount of landslides. The most unfortunate case occurred in the Xiaolin village, which was totally demolished by a catastrophic landslide in less than a minute. Continued and detailed study of the characteristics of large landslides is urgently needed to mitigate loss of lives and properties in the future. Traditionally known techniques cannot effectively extract landslide parameters, such as depth, amount and volume, which are essential in all the phases of landslide assessment. In addition, it is very important to record the changes of landslide deposits after the landslide events as accurately as possible to better understand the landslide erosion process. The acquisition of digital elevation models (DEMs) is considered necessary for achieving accurate, effective and quantitative landslide assessments. A new technique is presented in this study for quickly assessing extensive areas of large landslides. The technique uses DEMs extracted from several remote sensing approaches, including aerial photogrammetry, airborne LiDAR and UAV photogrammetry. We chose a large landslide event that occurred after Typhoon Sinlaku in Meiyuan the mount, central Taiwan in 2008. We collected and processed six data sets, including aerial photos, airborne LiDAR data and UAVphotos, at different times from 2005 to 2013. Our analyses show the landslide volume being 17.14 × 106 cubic meters, deposition volume being 12.75 × 106 cubic meters, and about 4.38 × 106 cubic meters being washed out of the region. Residual deposition ratio of this area is about 74% in 2008; while, after a few years, the residual deposition ratio is down below 50%. We also analyzed riverbed changes and sediment transfer patterns from 2005 to 2013 by multi-temporal remote sensing data with desirable accuracy. The developed technique will support damage and risk assessments of large landslides because the volume difference, riverbed change, and sediment migration can be quantitatively and accurately determined by a combination of multi-temporal remote sensing approaches.

  16. Development of Sub-Seasonal Remote Sensing Chlorophyll-A Detection Models

    Directory of Open Access Journals (Sweden)

    Carly Hansen

    2013-12-01

    Full Text Available Remote sensing techniques are proven methods for quantifying chlorophyll-a levels by inference algal concentrations in reservoirs. One traditional method is to use Landsat imagery and field data from a limited time period to develop a model for a reservoir which relates reflectance in various bands to measured algal (or chlorophyll-a concentrations and use that model and associated imagery to determine spatial algal concentrations in the reservoir. In this work, we extend these techniques to use historical Landsat data over long time periods to develop seasonal models that will more accurately describe the conditions throughout the growing season. Previous work at Deer Creek included the development of a chlorophyll-a model using data from the months of August to September. This model did not account for seasonal variation and algal succession, which affects the relationship between measured reflectance and algal concentration. Early summer algal blooms are dominated by diatoms (yellow-brown, while the algae vary from chlorophyta (green in the mid-summer to cyanobacteria (blue-green in late summer months. This study presents and explores the development and use of seasonal algorithms based on reflective characteristics of various algal communities to create a more accurate model for the reservoir. This study uses water quality data collected over a 20-year period during non-ice conditions along with associated Landsat data. As the field measurements were not taken to support remote sensing measurements, this study evaluates the use of historical data to support remote sensing analysis. It is assumed that reservoir conditions do not change rapidly, the field data can be used to develop correlations with satellite imagery taken within a day of the field measurements, and the seasonal algal communities have different reflective properties (or colors. We present statistical analysis that shows the seasonal algorithms better fit the data than the non-seasonal model and the traditional model calibrated with late-season data. We recommend the use of sub-seasonal algorithms to more accurately model and predict water quality throughout the growing season.

  17. Indications for body MRI

    International Nuclear Information System (INIS)

    The lack of ionizing radiation use in MRI makes the high spatial resolution technique very appealing. Also, the easy access to multiplanar imaging and the fact that gadolinium-DTPA is well tolerated and not nephrotoxic makes MRI a robust alternative in the healthy as well as the renal compromised patient. Furthermore, MRI adds advanced possibility for tissue characterization and pathology detection and dynamic imaging can be performed. Specific contrast agents specific to the hepatobiliary or the reticuloendothelial system can help with additional information in problem cases. The role of MRI for different organs is discussed and a review of the literature is given. We concluded that MRI is considered a useful and non-invasive diagnostic tool for the detection of hepatic iron concentration, to correct misdiagnosis (pseudolesions) from US and CT in focal steatosis and to help with focal lesion detection and characterization, in the healthy and especially in the cirrhotic liver, where MRI is superior to CT. Moreover, MRCP is excellent for identifying the presence and the level of biliary obstruction in malignant invasion and is considered in the literature as a non-invasive screening tool for common bile duct stones, appropriately selecting candidates for preoperative ERCP and sparing others the need for an endoscopic procedure with its associated complications. MRI is the first choice modality for adrenal evaluation in contemporary medical imaging. It is a useful examirary medical imaging. It is a useful examination in renal as well as splenic pathology and best assesses loco-regional staging, i.e. arterial involvement in pancreatic cancer

  18. A discriminative method for protein remote homology detection and fold recognition combining Top-n-grams and latent semantic analysis

    Directory of Open Access Journals (Sweden)

    Lin Lei

    2008-12-01

    Full Text Available Abstract Background Protein remote homology detection and fold recognition are central problems in bioinformatics. Currently, discriminative methods based on support vector machine (SVM are the most effective and accurate methods for solving these problems. A key step to improve the performance of the SVM-based methods is to find a suitable representation of protein sequences. Results In this paper, a novel building block of proteins called Top-n-grams is presented, which contains the evolutionary information extracted from the protein sequence frequency profiles. The protein sequence frequency profiles are calculated from the multiple sequence alignments outputted by PSI-BLAST and converted into Top-n-grams. The protein sequences are transformed into fixed-dimension feature vectors by the occurrence times of each Top-n-gram. The training vectors are evaluated by SVM to train classifiers which are then used to classify the test protein sequences. We demonstrate that the prediction performance of remote homology detection and fold recognition can be improved by combining Top-n-grams and latent semantic analysis (LSA, which is an efficient feature extraction technique from natural language processing. When tested on superfamily and fold benchmarks, the method combining Top-n-grams and LSA gives significantly better results compared to related methods. Conclusion The method based on Top-n-grams significantly outperforms the methods based on many other building blocks including N-grams, patterns, motifs and binary profiles. Therefore, Top-n-gram is a good building block of the protein sequences and can be widely used in many tasks of the computational biology, such as the sequence alignment, the prediction of domain boundary, the designation of knowledge-based potentials and the prediction of protein binding sites.

  19. Remote detection of corrosion activity by SQUID magnetometry across a multiphase medium under electrolyte flow conditions

    International Nuclear Information System (INIS)

    Hydrodynamic induction of magnetic fields on AA2024 sample corroding in NaOH solutions was studied by a Superconducting Quantum Interference Device (SQUID) magnetometer operating in liquid helium with a spatial resolution of approximately 1 mm. The hydrodynamic generation of magnetic fields was explained in terms of electronic and ionic currents induced by corrosion potential gradients within the sample due to different solution flow velocities. The intrinsic magnetic activity of the electrolyte flow was significantly less than that of the corroding sample. The measurements demonstrated a unique capability of magnetometry to sense corrosion remotely and across the integrated media consisting of gaseous and solid dielectrics (air, plastics), electronic conductor (aluminum alloy) and ionic one (solution)

  20. Remote Sensing and Modeling of Landslides: Detection, Monitoring and Risk Evaluation

    Science.gov (United States)

    Kirschbaum, Dalia; Fukuoka, Hiroshi

    2012-01-01

    Landslides are one of the most pervasive hazards in the world, resulting in more fatalities and economic damage than is generally recognized_ Occurring over an extensive range of lithologies, morphologies, hydrologies, and climates, mass movements can be triggered by intense or prolonged rainfall, seismicity, freeze/thaw processes, and antbropogertic activities, among other factors. The location, size, and timing of these processes are characteristically difficult to predict and assess because of their localized spatial scales, distribution, and complex interactions between rainfall infiltration, hydromechanical properties of the soil, and the underlying surface composition. However, the increased availability, accessibility, and resolution of remote sensing data offer a new opportunity to explore issues of landslide susceptibility, hazard, and risk over a variety of spatial scales. This special issue presents a series of papers that investigate the sources, behavior, and impacts of different mass movement types using a diverse set of data sources and evaluation methodologies.

  1. Investigations of remote sensing techniques for early detection of Dutch elm disease

    Science.gov (United States)

    Hammerschlag, R. S.; Sopstyle, W. J.

    1975-01-01

    Several forms of aerial photography were pursued in quest of a technique which could provide early detection of Dutch elm disease. The two most promising techniques tested were multispectral photography with object enhancement and biband ratioing coupled with scanning microdensitometry. For practical purposes the multispectral system has the advantage of providing a readily interpretable image in a relatively short time. Laboratory studies indicated that less emphasis should be placed on the use of a red filter or the near infrared beyond 750 mm for early detection of stress within a single plant species. Color infrared film would be optimal when used for a long term detection of loss of plant vigor which results in a physical change in a plant canopy, but should find minimal practicality for early detection of specific sources of plant stress such as Dutch elm disease. Considerable discretion should be used when interpreting imagery on copy film because of loss of resolution and color definition.

  2. Remote Sensing and Geographic Information System (GIS) Technologies for Natural Hazard Risk Site Detection

    International Nuclear Information System (INIS)

    Satellite imageries and digital elevation data of Turkey are investigated for detecting sites prone to natural hazards. Digital image processing methods used to enhance satellite data and to produce morphometric maps in order to contribute to the detection of causal factors related to landslides, local site conditions influencing and/or experiencing earthquake damage intensity or those of tsunami and storm surge hazard sites at the coasts

  3. Detection of powdery midiou in grapevine using remotely-sensed UV-induced fluorescence

    OpenAIRE

    Belanger, M. C.; Roger, J. M.; Cartolaro, P.; Viau, A.; Bellon-maurel, V.

    2008-01-01

    Powdery mildiou is caused by Erysiphe Necator, an acomycete fungus. It can induce severe damages to a vineyard including yield loss and depreciation of wine sensory charcateristics. This disease as other fungal diseases is throroughly controlled by pesticides. In order to reduce the use of pesticides and to improve early detection for these diseases, we studied the potential of UV-induced imaging fluorescence to detect and quantify the colonization of a leaf by E. necator. Cuttings of grapewi...

  4. Detecting Mountain Peaks and Delineating Their Shapes Using Digital Elevation Models, Remote Sensing and Geographic Information Systems Using Autometric Methodological Procedures

    OpenAIRE

    Tomaž Podobnikar

    2012-01-01

    The detection of peaks (summits) as the upper parts of mountains and the delineation of their shape is commonly confirmed by inspections carried out by mountaineers. In this study the complex task of peak detection and shape delineation is solved by autometric methodological procedures, more precisely, by developing relatively simple but innovative image-processing and spatial-analysis techniques (e.g., developing inventive variables using an annular moving window) in remote sensing and GIS d...

  5. MRI-detectable pH nanosensors incorporated into hydrogels for in vivo sensing of transplanted-cell viability

    Science.gov (United States)

    Chan, Kannie W. Y.; Liu, Guanshu; Song, Xiaolei; Kim, Heechul; Yu, Tao; Arifin, Dian R.; Gilad, Assaf A.; Hanes, Justin; Walczak, Piotr; van Zijl, Peter C. M.; Bulte, Jeff W. M.; McMahon, Michael T.

    2013-03-01

    Biocompatible nanomaterials and hydrogels have become an important tool for improving cell-based therapies by promoting cell survival and protecting cell transplants from immune rejection. Although their potential benefit has been widely evaluated, at present it is not possible to determine, in vivo, if and how long cells remain viable following their administration without the use of a reporter gene. Here, we report a pH-nanosensor-based magnetic resonance imaging (MRI) technique that can monitor cell death in vivo non-invasively. We demonstrate that specific MRI parameters that change on cell death of microencapsulated hepatocytes are associated with the measured bioluminescence imaging radiance. Moreover, the readout from this pH-sensitive nanosensor can be directly co-registered with high-resolution anatomical images. All of the components of these nanosensors are clinical grade and hence this approach should be a translatable and universal modification of hydrogels.

  6. Highway Traffic Incident Detection using High-Resolution Aerial Remote Sensing Imagery

    Directory of Open Access Journals (Sweden)

    Seyed M.M. Kahaki

    2011-01-01

    Full Text Available Problem statement: As vehicle population increases, Intelligent Transportation Systems (ITS become more significant and mandatory in today?s overpopulated world. Vital problems in transportation such as mobility and safety of transportation are considered more, especially in metropolitans and highways. The main road traffic monitoring aims are: the acquisition and analysis of traffic figures, such as number of vehicles, incident detection and automatic driver warning systems are developed mainly for localization and safety purposes. Approach: The objective of this investigation was to propose a strategy for road extraction and incident detection using aerial images. Real time extraction and localization of roadways in an satellite image is an emerging research field which can applied to vision-based traffic controlling and unmanned air vehicles navigation. Results: The results of the proposed incident detection algorithm show that it has good detection performance, the maximum angle of vehicles applied for incidet detection is 45 Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} ° and the performance for learning system in order to vehicle detection is 86%. This performance achived in testing algorithm on 45 highway aerial images. Conclusion: In order to consider with the high complexity of this kind of imagery, we integrate knowledge about roadways using formulated scale-dependent models. The intensity images are used for the extraction of road from satellite images. Threshold techniques, neural network and Radon transform are used for the road extraction, vehicle detection and incident detection. Results indicated that in most aerial images the incident can be detect by applying the angle algorithm.

  7. Optical detection of special nuclear materials: an alternative approach for standoff and remote sensing

    Science.gov (United States)

    Johnson, J. Bruce; Reeve, S. W.; Burns, W. A.; Allen, Susan D.

    2010-04-01

    Termed Special Nuclear Material (SNM) by the Atomic Energy Act of 1954, fissile materials, such as 235U and 239Pu, are the primary components used to construct modern nuclear weapons. Detecting the clandestine presence of SNM represents an important capability for Homeland Security. An ideal SNM sensor must be able to detect fissile materials present at ppb levels, be able to distinguish between the source of the detected fissile material, i.e., 235U, 239Pu, 233U or other fission source, and be able to perform the discrimination in near real time. A sensor with such capabilities would provide not only rapid identification of a threat but, ultimately, information on the potential source of the threat. For example, current detection schemes for monitoring clandestine nuclear testing and nuclear fuel reprocessing to provide weapons grade fissile material rely largely on passive air sampling combined with a subsequent instrumental analysis or some type of wet chemical analysis of the collected material. It would be highly useful to have a noncontact method of measuring isotopes capable of providing forensic information rapidly at ppb levels of detection. Here we compare the use of Kr, Xe and I as "canary" species for distinguishing between 235U and 239Pu fission sources by spectroscopic methods.

  8. A computer-aided detection system for rheumatoid arthritis MRI data interpretation and quantification of synovial activity

    Energy Technology Data Exchange (ETDEWEB)

    Kubassova, Olga, E-mail: olga@imageanalysis.org.u [Image Analysis Ltd., The Waterfront, Old Mill Lane, Saltaire BD17 7EZ (United Kingdom); Boesen, Mikael, E-mail: parker@frh.regionh.d [Parker Institute, Frederiksberg Hospital, Nordre Fasanvej 57, 2000 Frederiksberg, Copenhagen (Denmark); Cimmino, Marco A., E-mail: cimmino@unige.i [Clinica Reumatologica, DI.M.I., Universita di Genova, Viale Benedetto XV, 6, 16129 Genova (Italy); Bliddal, Henning [Parker Institute, Frederiksberg Hospital, Nordre Fasanvej 57, 2000 Frederiksberg, Copenhagen (Denmark)

    2010-06-15

    Rational and objective: Disease assessment and follow-up of rheumatoid arthritis (RA) patients require objective evaluation and quantification. Magnetic resonance imaging (MRI) has a large potential to supplement such information for the clinician, however, time spent on data reading and interpretation slow down development in this area. Existing scoring systems of especially synovitis are too rigid and insensitive to measure early treatment response and quantify inflammation. This study tested a novel automated, computer system for analysis of dynamic MRI data acquired from patients with RA, Dynamika-RA, which incorporates efficient data processing and analysis techniques. Materials and methods: 140 MRI scans from hands and wrists of 135 active RA patients and 5 healthy controls were processed using Dynamika-RA and evaluated with RAMRIS. To reduce patient motion artefacts, MRI data were processed using Dynamika-RA, which removed motion in 2D and 3D planes. Then synovial enhancement was visualised and qualified using a novel fully automated voxel-by-voxel analysis based algorithm. This algorithm was used to replace traditional region-of-interest (ROI) and subtraction methods, yielding observer independent quantitative results. Results: Conventional scoring performed by an observer took 30-45 min per dataset. Dynamika-RA reduced motion artefacts, visualised inflammation and quantified disease activity in less than 3 min. Data processing allowed increasing signal to noise ratio by a factor 3. Due to fully automated procedure of data processing, there was no intertest variation in the results. Conclusions: Algorithms incorporated into Dynamika-RA allow for the significant enhancement of data quality through eliminating motion artefacts and reduction of time for evaluation of synovial inflammation.

  9. Impact of functional MRI data preprocessing pipeline on default-mode network detectability in patients with disorders of consciousness

    OpenAIRE

    LudovicoMinati; AdrianAndronache

    2013-01-01

    An emerging application of resting-state functional MRI is the study of patients with disorders of consciousness (DoC), where integrity of default-mode network (DMN) activity is associated to the clinical level of preservation of consciousness. Due to the inherent inability to follow verbal instructions, arousal induced by scanning noise and postural pain, these patients tend to exhibit substantial levels of movement. This results in spurious, non-neural fluctuations of the blood-oxygen level...

  10. MRI-detectable pH nanosensors incorporated into hydrogels for in vivo sensing of transplanted cell viability

    OpenAIRE

    Chan, Kannie W. Y.; Liu, Guanshu; Song, Xiaolei; Kim, Heechul; Yu, Tao; Arifin, Dian R.; Gilad, Assaf A.; Hanes, Justin; Walczak, Piotr; Zijl, Peter C. M.; Bulte, Jeff W. M.; Mcmahon, Michael T.

    2013-01-01

    Biocompatible nanomaterials and hydrogels have become an important tool for improving cell-based therapies by promoting cell survival and protecting cell transplants from immune rejection. Although their potential benefit has been widely evaluated, it is currently not possible to determine, in vivo, if and how long cells remain viable following their administration without the use of a reporter gene. We here report a pH nanosensor-based magnetic resonance imaging (MRI) technique that can moni...

  11. Imaging diagnosis of the internal jugular vein invasion by cervical metastatic lymphnodes. Detection with CT, MRI and US

    International Nuclear Information System (INIS)

    Preoperative assessment of the invasion to the internal jugular vein (IJV) by cervical metastatic lymphnodes is of great clinical importance, because intracranial complications and blindness may occur after resection of unilateral or bilateral IJV at radical neck dissections. To avoid such adverse events, operators should pay the efforts to preserve the IJV at neck dissections, if possible. To diagnose invasion of the IJV, the findings by computed tomography (CT), magnetic resonance imaging (MRI) and ultrasonic scan (US) were compared with pathological findings in 21 metastatic lymphnodes of 16 patients with head and neck carcinomas. The IJV will be separated from the metastatic lymphnodes at neck dissections in cases which have the loose connective tissue between the IJV and the lymphnodes. The loose connective tissue was seen in 13 metastatic lymphnodes. It was considered that the presence of the low density layer on CT, the high signal layer on MRI and the hyperechoic layer on US between the metastatic lymphnodes and the IJV meant the presence of this loose connective tissue. In cases which had these layers on CT, MRI and US between the metastatic lymphnodes and the IJV or had circumference of less than 120 degrees of contact area of the IJV and the metastatic lymphnodes on CT, MRI and US or had vertical length of less than 40 mm of contact area of the IJV and the metastatic lymphnodes on US, there were no invasion of the IJV. In these cases, we believe that we canJV. In these cases, we believe that we can do neck dissections with preservasion of the IJV. (author)

  12. Differentiation between Benign and Malignant Breast Lesions Detected by Bilateral Dynamic Contrast-Enhanced MRI: A Sensitivity and Specificity Study

    OpenAIRE

    Jansen, Sanaz A.; Fan, Xiaobing; Karczmar, Gregory S.; Abe, Hiroyuki; Schmidt, Robert A.; Newstead, Gillian M.

    2008-01-01

    The purpose of this study was to apply an empirical mathematical model (EMM) to kinetic data acquired under a clinical protocol to determine if the sensitivity and specificity can be improved compared with qualitative BI-RADS descriptors of kinetics. 3D DCE-MRI data from 100 patients with 34 benign and 79 malignant lesions were selected for review under an Institutional Review Board (IRB)-approved protocol. The sensitivity and specificity of the delayed phase classification were 91% and 18%, ...

  13. Detection of deep water formation from remote sensing chlorophyll in the NW Mediterranean Sea

    Science.gov (United States)

    Bernardello, Raffaele; Bahamon, Nixon; Ahumada, Miguel-Angel; Martin, Adrian; Henson, Stephanie

    2015-04-01

    The Northwestern Mediterranean Sea is one of the few regions in the world where Deep Water Formation (DWF) occurs. During wintertime cold and dry winds that typically occur in strong bursts lasting a few days, are able to erode the near-surface stability over this area, exposing the weakly stratified underwaters and initiate a phase of violent mixing and deep convection. DWF is not a steady-state process that recurs every year. Variations in wind stress and heat flux over the winter can induce a marked interannual variability: during some years the process is specially intense and completely absent during others. The extent of the area over which DWF occurs is also uncertain. The interannual variability of the DWF process is also associated to the variability in the seasonal phytoplankton dynamics over the area. The extent of the vertical mixing set the total amount of nutrients available for the phytoplankton during the following spring bloom. However, before the bloom, when deep convection is still active, surface chlorophyll (an index for phytoplankton biomass) is vertically diluted showing low surface concentration. The occurrence of these patches of anomalously low chlorophyll concentration can, in principle, be associated to the presence of active deep convection. In this study we investigate the possibility of exploiting such association in order to quantify the duration of deep convection and the extent of the area over which it occurs. These goals will be achieved through the analysis of remote sensing chlorophyll data and in-situ Argo-floats profiles.

  14. Quantum Boosting and Fast Classical Metrics for Tree Cover Detection in Remote Sensing Data

    Science.gov (United States)

    Boyda, E.; Basu, S.; Ganguly, S.; Michaelis, A.; Nemani, R. R.

    2014-12-01

    New volumes of high resolution remote sensing imagery hold greatpromise for Earth science, and with it, new challenges in machinelearning. Familiar heuristic training routines become impractical asdatasets scale to terabytes and beyond. Now, emerging quantumhardware from D-wave Systems allows us to explore alternatives basedon the principles of adiabatic quantum computation. As part of aprogram to develop tree cover estimates for the continental UnitedStates based on one-meter-resolution National Agriculture ImageryProgram (NAIP) data, we have implemented a binary classifier, known asQboost, to combine in a principled manner decision stumps definedon features extracted from 8x8 pixel squares. Qboost was originallydeveloped to be trained on D-wave hardware. Prototyped on NAIP datafor the state of California, the classifier discrimates tree-covered regions with a validationerror rate of 8%. Additionally, we identify quadratic combinationsof the Atmospherically Resistant Vegetation Index (ARVI) and standarddeviations of intensity or near-infrared reflectance that providefast, simple, classical metrics to identify tree cover. They cut by nearly half theerror rates of ARVI used alone or of our best single-featurediscriminant.

  15. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... can help diagnose conditions such as: brain tumors stroke infections developmental anomalies hydrocephalus — dilatation of fluid spaces ... pg=angiomr) for more information. MRI can detect stroke at a very early stage by mapping the ...

  16. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... MRI can detect stroke at a very early stage by mapping the motion of water molecules in ... have been acutely injured; however, this is a clinical judgment. This is because traction devices and many ...

  17. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... examination to detect brain abnormalities in patients with dementia, a disorder that can cause confusion or memory ... This detail makes MRI an invaluable tool in early diagnosis and evaluation of many conditions, including tumors. ...

  18. Contralateral lesions detected by preoperative MRI in patients with recently diagnosed breast cancer: Application of MR CAD in differentiation of benign and malignant lesions

    International Nuclear Information System (INIS)

    Objectives: To retrospectively investigate the added value of kinetic features measured by computer-aided diagnosis (CAD) for differentiating benign and malignant contralateral breast lesions detected by preoperative MRI in breast cancer patients. Methods: This study was approved by our institutional review board, and the requirement for informed consent was waived. Fifty-two breast MR images and their CAD kinetic features were obtained for 52 consecutive breast cancer patients with contralateral breast lesions detected by preoperative MRI and confirmed by excision (23 cancers and 29 benign lesions). Three experienced radiologists independently reviewed the MR images without CAD information and assessed probabilities of malignancy. Four weeks later, these probabilities were reanalyzed using stored CAD data. Diagnostic performances and detection rates of delayed washout components were compared between interpretations without and with CAD for each reader. Results: Use of MR CAD increased detection of washout component by 2.4- to 3.7-fold than visual assessment for enhancing contralateral lesions, which increased sensitivity (91% vs. 87% in reader 1; 96% vs. 74% in reader 2; 91% vs. 70% in reader 3) and decreased specificity, but statistical significance was only found for decreased specificity in one reader (52% vs. 28%, P = 0.039), and overall performance (areas under ROC curves 0.672 vs. 0.616 in reader 1; 0.624 vs. 0.603 in reader 2; 0.706 vs. 0.590 in reader 3) remreader 2; 0.706 vs. 0.590 in reader 3) remained unimproved. Conclusion: Addition of MR CAD increased sensitivity and decreased specificity than radiologist's assessment alone for differentiating benign and malignant contralateral lesions in breast cancer patients and overall performance remained unimproved.

  19. Development principles of frequency-modulated CW-ladar for remote detection of atmospheric trace constituents

    Science.gov (United States)

    Agishev, Ravil R.; Sagdiev, Rafael K.; Gross, Barry; Moshary, Fred; Gilerson, Alexander; Ahmed, Samir; Comeron, Adolfo

    2004-09-01

    In this paper we present a general methodology for a frequency-modulated ladar/lidar (CW-FM-ladar/lidar) concept based on principles of both CW-FM-range-finding and modulation spectroscopy, together with modern techniques of optical signal transmission using tunable laser diodes, signal detection and heterodyne processing. We develop a mathematical description of trace gas detection using CW-LD ladar developing the relationship between the heterodyne echo-signal amplitudes and frequencies and trace gas concentration for each range. In particular, precise range and gas retrieval resolution limits based on the transmitting signal modulation and absorption line parameters are obtained.

  20. Detection of pollution-induced forest decline in the Kola Peninsula using remote sensing and mathematical modelling

    International Nuclear Information System (INIS)

    Forests on the Kola Peninsula in Northern Russia grow close to the northern tree line. They are subjected to both natural and anthropogenic stress factors. The Cu-Ni smelter 'Severonikel' (Lat. 67 deg 55'N; Long. 32 deg 57'E) near Monchegorsk is one of the two major sources of sulphur dioxide and heavy metals emissions on the Kola Peninsula. These emissions have caused significant deterioration of the surrounding vegetation. The thesis demonstrates how methods of Remote sensing, ground survey and mathematical modelling can be integrated for monitoring of the smelter's environmental impact on the surrounding vegetation: ground truth data are used for calibration of remote-sensed data, which further serve to verify mathematical models. The study aims were: * to estimate the scale of airborne sulphur pollution from the smelting industry on the Kola Peninsula and its effect on vegetation; * to assess spatial extent of the forest decline in the 'Severonikel' smelter impact zone; * to display dynamics of the forest damage area in spatial and temporal perspective; * to validate the Gaussian plume sector model and the IIASA forest impact model as components of the analysis of forest damage. The Regional Acidification Information and Simulation model (RAINS) was applied to calculate sulphur deposition and loads in Fennoscandia in order to assess the contribution of the Kola sources to the deposition pattern in the region. The percentage of the ecosystems where the critical load had been exceeded was calculated. For more detailed assessments, calculations based on local and meso-scale models were made. Landsat-MSS summer images from 1978, 1986 and 1992 and a Landsat -TM image from 1996 were used for change-detection analyses. The methods applied were bandwise histogram matching and subsequent differencing. An unsupervised classification of land-cover was made using the 1996 Landsat-TM image. In situ observations of vegetation type and degradation levels on permanent field plots were used for labelling the classes. Multispectral changes observed between 1978 and 1992 were used to evaluate the relevance of the Gaussian plume model as a component for assessment of forest decline. The IIASA model for accumulated impact in forests under long-term exposure to airborne sulphur was applied for the period of 1960-1996. The input data used were plant sensitivity parameters and SO2 ambient concentrations predicted at a previous stage. The model was validated by ground truth data and the results of the 1996 classification. Effects of topography and episodes of high concentrations were additionally investigated by a 3D numerical modelling Results: * Comparative analysis by the RAINS model showed a significant, but local impact of the Kola sources on adjacent parts of the Nordic countries. * Remote sensing has revealed vegetation decline in large areas around the 'Severonikel'. The damaged area expands more north than south of the smelter due to a dominance of southern winds during the vegetation period, and a sheltering role of topography as revealed by 3D modelling. * Multispectral changes detected between 1978 and 1992 were found to have a statistically significant correspondence to the modelled long-term SO2 concentration levels in ambient air. This validates the Gaussian plume model. * The impact model was validated by in situ field data and by the classified 1996 scene. * Both Remote sensing analysis and the impact model show a rapid expansion of the degraded area during 1978-1992 and its stabilisation since that time which is consistent with the reduced emissions. * An exceptional expansion of forest damage south of the smelter in 1992 is likely to be linked to an episode of high concentration prior to the image acquisition or extreme climatic conditions

  1. Detection of pollution-induced forest decline in the Kola Peninsula using remote sensing and mathematical modelling

    Energy Technology Data Exchange (ETDEWEB)

    Rigina, Olga

    1998-07-01

    Forests on the Kola Peninsula in Northern Russia grow close to the northern tree line. They are subjected to both natural and anthropogenic stress factors. The Cu-Ni smelter 'Severonikel' (Lat. 67 deg 55'N; Long. 32 deg 57'E) near Monchegorsk is one of the two major sources of sulphur dioxide and heavy metals emissions on the Kola Peninsula. These emissions have caused significant deterioration of the surrounding vegetation. The thesis demonstrates how methods of Remote sensing, ground survey and mathematical modelling can be integrated for monitoring of the smelter's environmental impact on the surrounding vegetation: ground truth data are used for calibration of remote-sensed data, which further serve to verify mathematical models. The study aims were: * to estimate the scale of airborne sulphur pollution from the smelting industry on the Kola Peninsula and its effect on vegetation; * to assess spatial extent of the forest decline in the 'Severonikel' smelter impact zone; * to display dynamics of the forest damage area in spatial and temporal perspective; * to validate the Gaussian plume sector model and the IIASA forest impact model as components of the analysis of forest damage. The Regional Acidification Information and Simulation model (RAINS) was applied to calculate sulphur deposition and loads in Fennoscandia in order to assess the contribution of the Kola sources to the deposition pattern in the region. The percentage of the ecosystems where the critical load had been exceeded was calculated. For more detailed assessments, calculations based on local and meso-scale models were made. Landsat-MSS summer images from 1978, 1986 and 1992 and a Landsat -TM image from 1996 were used for change-detection analyses. The methods applied were bandwise histogram matching and subsequent differencing. An unsupervised classification of land-cover was made using the 1996 Landsat-TM image. In situ observations of vegetation type and degradation levels on permanent field plots were used for labelling the classes. Multispectral changes observed between 1978 and 1992 were used to evaluate the relevance of the Gaussian plume model as a component for assessment of forest decline. The IIASA model for accumulated impact in forests under long-term exposure to airborne sulphur was applied for the period of 1960-1996. The input data used were plant sensitivity parameters and SO{sub 2} ambient concentrations predicted at a previous stage. The model was validated by ground truth data and the results of the 1996 classification. Effects of topography and episodes of high concentrations were additionally investigated by a 3D numerical modelling Results: * Comparative analysis by the RAINS model showed a significant, but local impact of the Kola sources on adjacent parts of the Nordic countries. * Remote sensing has revealed vegetation decline in large areas around the 'Severonikel'. The damaged area expands more north than south of the smelter due to a dominance of southern winds during the vegetation period, and a sheltering role of topography as revealed by 3D modelling. * Multispectral changes detected between 1978 and 1992 were found to have a statistically significant correspondence to the modelled long-term SO{sub 2} concentration levels in ambient air. This validates the Gaussian plume model. * The impact model was validated by in situ field data and by the classified 1996 scene. * Both Remote sensing analysis and the impact model show a rapid expansion of the degraded area during 1978-1992 and its stabilisation since that time which is consistent with the reduced emissions. * An exceptional expansion of forest damage south of the smelter in 1992 is likely to be linked to an episode of high concentration prior to the image acquisition or extreme climatic conditions.

  2. Detection of a new methanol maser line with the Kitt Peak 12-m telescope by remote observing from Moscow

    CERN Document Server

    Slysh, V I; Valtts, I E; Golubev, V B

    1997-01-01

    A new methanol maser line 6(-1)-5(0)E at 133 GHz was detected with the 12-m Kitt Peak radio telescope using remote observation mode from Moscow. Moderately strong, narrow maser lines were found in DR21(OH), DR21-W, OMC-2, M8E, NGC2264, L379, W33-Met. The masers have similar spectral features in other transitions of methanol-E at 36 and 84 GHz, and in transitions of methanol-A at 44 and 95 GHz. All these are Class I transitions, and the new masers also belong to Class I. In two other methanol transitions near 133 GHz, 5(-2)-6(-1)E and 6(2)-7(1)A+, only thermal emission was detected in some sources. Several other sources with wider lines in the transition 6(-1)-5(0)E also may be masers, since they do not show any emission at the two other methanol transitons near 133 GHz. These are NGC2071, S231, S255, GGD27, also known as Class I masers. The ratio of intensities and line widths of the 133 GHz masers and 44 GHz masers is consistent with the saturated maser model, in which the line rebroadening with respect to u...

  3. Detection of Seagrass Distribution Changes from 1991 to 2006 in Xincun Bay, Hainan, with Satellite Remote Sensing

    Directory of Open Access Journals (Sweden)

    Chaoyu Yang

    2009-02-01

    Full Text Available Seagrass distribution is a very important index for costal management and protection. Seagrass distribution changes can be used as indexes to analyze the reasons for the changes. In this paper, in situ hyperspectral observation and satellite images of QuickBird, CBERS (China Brazil Earth Resources Satellite data and Landsat data were used to retrieve bio-optical models and seagrass (Enhalus acoroides,Thalassia hemperichii distribution in Xincun Bay, Hainan province, and seagrass distribution changes from 1991 to 2006 were analyzed. Hyperspectral results showed that the spectral bands at 555, 635, 650 and 675 nm are sensitive to leaf area index (LAI. Seagrass detection with QuickBird was more accurate than that with Landsat TM and CBERS; five classes could be classified clearly and used as correction for seagrass remote sensing data from Landsat TM and CBERS. In order to better describe seagrass distribution changes, the seagrass distribution area was divided as three regions: region A connected with region B in 1991, however it separated in 1999 and was wholly separated in 2001; seagrass in region C shrank gradually and could not be detected in 2006. Analysis of the reasons for seagrass reduction indicated it was mainly affected by aquaculture and typhoons and in recent years, by land use changes.