WorldWideScience

Sample records for image sequences acquired

  1. Rapid 3D Reconstruction for Image Sequence Acquired from UAV Camera

    Directory of Open Access Journals (Sweden)

    Yufu Qu

    2018-01-01

    Full Text Available In order to reconstruct three-dimensional (3D structures from an image sequence captured by unmanned aerial vehicles’ camera (UAVs and improve the processing speed, we propose a rapid 3D reconstruction method that is based on an image queue, considering the continuity and relevance of UAV camera images. The proposed approach first compresses the feature points of each image into three principal component points by using the principal component analysis method. In order to select the key images suitable for 3D reconstruction, the principal component points are used to estimate the interrelationships between images. Second, these key images are inserted into a fixed-length image queue. The positions and orientations of the images are calculated, and the 3D coordinates of the feature points are estimated using weighted bundle adjustment. With this structural information, the depth maps of these images can be calculated. Next, we update the image queue by deleting some of the old images and inserting some new images into the queue, and a structural calculation of all the images can be performed by repeating the previous steps. Finally, a dense 3D point cloud can be obtained using the depth–map fusion method. The experimental results indicate that when the texture of the images is complex and the number of images exceeds 100, the proposed method can improve the calculation speed by more than a factor of four with almost no loss of precision. Furthermore, as the number of images increases, the improvement in the calculation speed will become more noticeable.

  2. Rapid 3D Reconstruction for Image Sequence Acquired from UAV Camera.

    Science.gov (United States)

    Qu, Yufu; Huang, Jianyu; Zhang, Xuan

    2018-01-14

    In order to reconstruct three-dimensional (3D) structures from an image sequence captured by unmanned aerial vehicles' camera (UAVs) and improve the processing speed, we propose a rapid 3D reconstruction method that is based on an image queue, considering the continuity and relevance of UAV camera images. The proposed approach first compresses the feature points of each image into three principal component points by using the principal component analysis method. In order to select the key images suitable for 3D reconstruction, the principal component points are used to estimate the interrelationships between images. Second, these key images are inserted into a fixed-length image queue. The positions and orientations of the images are calculated, and the 3D coordinates of the feature points are estimated using weighted bundle adjustment. With this structural information, the depth maps of these images can be calculated. Next, we update the image queue by deleting some of the old images and inserting some new images into the queue, and a structural calculation of all the images can be performed by repeating the previous steps. Finally, a dense 3D point cloud can be obtained using the depth-map fusion method. The experimental results indicate that when the texture of the images is complex and the number of images exceeds 100, the proposed method can improve the calculation speed by more than a factor of four with almost no loss of precision. Furthermore, as the number of images increases, the improvement in the calculation speed will become more noticeable.

  3. The role of MR imaging with Half Fourier Acquired Single Shot Turbo Spin Echo sequence in the diagnosis of lung lesions in comparison with multislice CT

    International Nuclear Information System (INIS)

    Hekimoglu, B.; Gurgen, F.; Tatar, I.G.; Aydin, H.; Kizilgoz, V.; Keyik, B.

    2013-01-01

    Objective: To compare the diagnostic values of magnetic resonance imaging using Half Fourier Acquired Single Shot Turbo Spin Echo sequence and multidetector computed tomography in patients with pathologically examined pulmonary lesions. Methods: The retrospective, descriptive study was conducted at Radiology Department, Diskapi Research Hospital, Ankara, Turkey, and comprised records of patients with pathologically examined pulmonary lesions between May 2009 and March 2012. Patients were divided into three groups and examined by both multi dedector computed tomography and magnetic resonance imaging. During the imaging, patients were not administered any intravenous contrast medium. Electrocardiogram gating and breath holding were not performed in echo sequence. Pulmonary lesions were evaluated on the basis of their dimensions, numbers, differentiation from atelectasis and consolidation, invasion to the thoracic wall-mediastinal structures and presence of lymphadenopathies. Results: Sensitivity of all patients was 50% (p=0.214) and specificity of CT and MRI were 82.5% (p=0.134) for the detectability of submilimetric nodules . For differentiation of the mass from atelectasis and consolidation, the sensitivity of computed tomography was statistically more significant compared to magnetic resonance imaging (86.6%; p=0.035). For the invasion of the mass to the mediastinal structures and the thoracic wall, the sensitivity of magnetic resonance imaging was statistically more significant compared to tomography (86.6%; p=0.035). Conclusion: HASTE sequence can be used to determine the invasion of the pulmonary mass to the mediastinal structures and the thoracic wall since it is more sensitive than computed tomography. It can also be used to detect submilimetric nodules. It has equal sensitivity and specificity compared to computed tomography. But computed tomography is superior for the differentiation of the mass from atelectasis and consolidation. (author)

  4. Software for Acquiring Image Data for PIV

    Science.gov (United States)

    Wernet, Mark P.; Cheung, H. M.; Kressler, Brian

    2003-01-01

    PIV Acquisition (PIVACQ) is a computer program for acquisition of data for particle-image velocimetry (PIV). In the PIV system for which PIVACQ was developed, small particles entrained in a flow are illuminated with a sheet of light from a pulsed laser. The illuminated region is monitored by a charge-coupled-device camera that operates in conjunction with a data-acquisition system that includes a frame grabber and a counter-timer board, both installed in a single computer. The camera operates in "frame-straddle" mode where a pair of images can be obtained closely spaced in time (on the order of microseconds). The frame grabber acquires image data from the camera and stores the data in the computer memory. The counter/timer board triggers the camera and synchronizes the pulsing of the laser with acquisition of data from the camera. PIVPROC coordinates all of these functions and provides a graphical user interface, through which the user can control the PIV data-acquisition system. PIVACQ enables the user to acquire a sequence of single-exposure images, display the images, process the images, and then save the images to the computer hard drive. PIVACQ works in conjunction with the PIVPROC program which processes the images of particles into the velocity field in the illuminated plane.

  5. Acquiring Procedural Skills from Lesson Sequences.

    Science.gov (United States)

    1985-08-13

    Teachers of Mathematics . Washington, D)C: NCTM . Brueckner, I..J. (1930) Diagnostic aund remedial teaching in arithmetic. Philadelphia. PA: Winston. Burton...arithmetic and algebra, fr-m multi-lesson curricula. The central hypothesis is that students and teachers obey cc: :-.entions that cause the goal hierarchy...students and • . teachers obey conventions that cause the goal hierarchy of the acquired procedure to be a particular structural function of the sequential

  6. Contribution to the tracking and the 3D reconstruction of scenes composed of torus from image sequences a acquired by a moving camera

    International Nuclear Information System (INIS)

    Naudet, S.

    1997-01-01

    The three-dimensional perception of the environment is often necessary for a robot to correctly perform its tasks. One solution, based on the dynamic vision, consists in analysing time-varying monocular images to estimate the spatial geometry of the scene. This thesis deals with the reconstruction of torus by dynamic vision. Though this object class is restrictive, it enables to tackle the problem of reconstruction of bent pipes usually encountered in industrial environments. The proposed method is based on the evolution of apparent contours of objects in the sequence. Using the expression of torus limb boundaries, it is possible to recursively estimate the object three-dimensional parameters by minimising the error between the predicted projected contours and the image contours. This process, which is performed by a Kalman filter, does not need a precise knowledge of the camera displacement or any matching of the tow limbs belonging to the same object. To complete this work, temporal tracking of objects which deals with occlusion situations is proposed. The approach consists in modeling and interpreting the apparent motion of objects in the successive images. The motion interpretation, based on a simplified representation of the scene, allows to recover pertinent three-dimensional information which is used to manage occlusion situations. Experiments, on synthetic and real images, proves he validity of the tracking and the reconstruction processes. (author)

  7. Acquired portosystemic collaterals: anatomy and imaging

    Energy Technology Data Exchange (ETDEWEB)

    Leite, Andrea Farias de Melo; Mota Junior, Americo, E-mail: andreafariasm@gmail.com [Instituto de Medicina Integral Professor Fernando Figueira de Pernambuco (IMIP), Recife, PE (Brazil); Chagas-Neto, Francisco Abaete [Universidade de Fortaleza (UNIFOR), Fortaleza, CE (Brazil); Teixeira, Sara Reis; Elias Junior, Jorge; Muglia, Valdair Francisco [Universidade de Sao Paulo (FMRP/USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina

    2016-07-15

    Portosystemic shunts are enlarged vessels that form collateral pathological pathways between the splanchnic circulation and the systemic circulation. Although their causes are multifactorial, portosystemic shunts all have one mechanism in common - increased portal venous pressure, which diverts the blood flow from the gastrointestinal tract to the systemic circulation. Congenital and acquired collateral pathways have both been described in the literature. The aim of this pictorial essay was to discuss the distinct anatomic and imaging features of portosystemic shunts, as well as to provide a robust method of differentiating between acquired portosystemic shunts and similar pathologies, through the use of illustrations and schematic drawings. Imaging of portosystemic shunts provides subclinical markers of increased portal venous pressure. Therefore, radiologists play a crucial role in the identification of portosystemic shunts. Early detection of portosystemic shunts can allow ample time to perform endovascular shunt operations, which can relieve portal hypertension and prevent acute or chronic complications in at-risk patient populations. (author)

  8. Acquired portosystemic collaterals: anatomy and imaging

    International Nuclear Information System (INIS)

    Leite, Andrea Farias de Melo; Mota Junior, Americo; Chagas-Neto, Francisco Abaete; Teixeira, Sara Reis; Elias Junior, Jorge; Muglia, Valdair Francisco

    2016-01-01

    Portosystemic shunts are enlarged vessels that form collateral pathological pathways between the splanchnic circulation and the systemic circulation. Although their causes are multifactorial, portosystemic shunts all have one mechanism in common - increased portal venous pressure, which diverts the blood flow from the gastrointestinal tract to the systemic circulation. Congenital and acquired collateral pathways have both been described in the literature. The aim of this pictorial essay was to discuss the distinct anatomic and imaging features of portosystemic shunts, as well as to provide a robust method of differentiating between acquired portosystemic shunts and similar pathologies, through the use of illustrations and schematic drawings. Imaging of portosystemic shunts provides subclinical markers of increased portal venous pressure. Therefore, radiologists play a crucial role in the identification of portosystemic shunts. Early detection of portosystemic shunts can allow ample time to perform endovascular shunt operations, which can relieve portal hypertension and prevent acute or chronic complications in at-risk patient populations. (author)

  9. Region segmentation along image sequence

    International Nuclear Information System (INIS)

    Monchal, L.; Aubry, P.

    1995-01-01

    A method to extract regions in sequence of images is proposed. Regions are not matched from one image to the following one. The result of a region segmentation is used as an initialization to segment the following and image to track the region along the sequence. The image sequence is exploited as a spatio-temporal event. (authors). 12 refs., 8 figs

  10. Image sequence analysis

    CERN Document Server

    1981-01-01

    The processing of image sequences has a broad spectrum of important applica­ tions including target tracking, robot navigation, bandwidth compression of TV conferencing video signals, studying the motion of biological cells using microcinematography, cloud tracking, and highway traffic monitoring. Image sequence processing involves a large amount of data. However, because of the progress in computer, LSI, and VLSI technologies, we have now reached a stage when many useful processing tasks can be done in a reasonable amount of time. As a result, research and development activities in image sequence analysis have recently been growing at a rapid pace. An IEEE Computer Society Workshop on Computer Analysis of Time-Varying Imagery was held in Philadelphia, April 5-6, 1979. A related special issue of the IEEE Transactions on Pattern Anal­ ysis and Machine Intelligence was published in November 1980. The IEEE Com­ puter magazine has also published a special issue on the subject in 1981. The purpose of this book ...

  11. Realise : reconstruction of reality from image sequences

    NARCIS (Netherlands)

    Leymarie, F.; de la Fortelle, A.; Koenderink, Jan J.; Kappers, A. M L; Stavridi, M.; van Ginneken, B.; Muller, S.; Krake, S.; Faugeras, O.; Robert, L.; Gauclin, C.; Laveau, S.; Zeller, C.; Anon,

    1996-01-01

    REALISE has for principal goals to extract from sequences of images, acquired with a moving camera, information necessary for determining the 3D (CAD-like) structure of a real-life scene together with information about the radiometric signatures of surfaces bounding the extracted 3D objects (e.g.

  12. Image registration method for medical image sequences

    Science.gov (United States)

    Gee, Timothy F.; Goddard, James S.

    2013-03-26

    Image registration of low contrast image sequences is provided. In one aspect, a desired region of an image is automatically segmented and only the desired region is registered. Active contours and adaptive thresholding of intensity or edge information may be used to segment the desired regions. A transform function is defined to register the segmented region, and sub-pixel information may be determined using one or more interpolation methods.

  13. Imaging of acquired non-traumatic cochlear lesions: iconographic essay

    International Nuclear Information System (INIS)

    Garcia, Marcelo de Mattos; Gonzaga, Juliana Gontijo

    2006-01-01

    Different non-traumatic acquired cochlear lesions are shown in this article with imaging methods. They may be responsible for neuro sensorial hearing loss or vertigo. The method of choice is computed tomography when evaluating the osseous labyrinth whereas magnetic resonance imaging has superior resolution in the studies of the membranaceous labyrinth. (author)

  14. Contribution to the tracking and the 3D reconstruction of scenes composed of torus from image sequences a acquired by a moving camera; Contribution au suivi et a la reconstruction de scenes constituees d`objet toriques a partir de sequences d`images acquises par une camera mobile

    Energy Technology Data Exchange (ETDEWEB)

    Naudet, S

    1997-01-31

    The three-dimensional perception of the environment is often necessary for a robot to correctly perform its tasks. One solution, based on the dynamic vision, consists in analysing time-varying monocular images to estimate the spatial geometry of the scene. This thesis deals with the reconstruction of torus by dynamic vision. Though this object class is restrictive, it enables to tackle the problem of reconstruction of bent pipes usually encountered in industrial environments. The proposed method is based on the evolution of apparent contours of objects in the sequence. Using the expression of torus limb boundaries, it is possible to recursively estimate the object three-dimensional parameters by minimising the error between the predicted projected contours and the image contours. This process, which is performed by a Kalman filter, does not need a precise knowledge of the camera displacement or any matching of the tow limbs belonging to the same object. To complete this work, temporal tracking of objects which deals with occlusion situations is proposed. The approach consists in modeling and interpreting the apparent motion of objects in the successive images. The motion interpretation, based on a simplified representation of the scene, allows to recover pertinent three-dimensional information which is used to manage occlusion situations. Experiments, on synthetic and real images, proves he validity of the tracking and the reconstruction processes. (author) 127 refs.

  15. Spatio-temporal alignment of pedobarographic image sequences.

    Science.gov (United States)

    Oliveira, Francisco P M; Sousa, Andreia; Santos, Rubim; Tavares, João Manuel R S

    2011-07-01

    This article presents a methodology to align plantar pressure image sequences simultaneously in time and space. The spatial position and orientation of a foot in a sequence are changed to match the foot represented in a second sequence. Simultaneously with the spatial alignment, the temporal scale of the first sequence is transformed with the aim of synchronizing the two input footsteps. Consequently, the spatial correspondence of the foot regions along the sequences as well as the temporal synchronizing is automatically attained, making the study easier and more straightforward. In terms of spatial alignment, the methodology can use one of four possible geometric transformation models: rigid, similarity, affine, or projective. In the temporal alignment, a polynomial transformation up to the 4th degree can be adopted in order to model linear and curved time behaviors. Suitable geometric and temporal transformations are found by minimizing the mean squared error (MSE) between the input sequences. The methodology was tested on a set of real image sequences acquired from a common pedobarographic device. When used in experimental cases generated by applying geometric and temporal control transformations, the methodology revealed high accuracy. In addition, the intra-subject alignment tests from real plantar pressure image sequences showed that the curved temporal models produced better MSE results (P alignment of pedobarographic image data, since previous methods can only be applied on static images.

  16. 3D MODEL GENERATION USING OBLIQUE IMAGES ACQUIRED BY UAV

    Directory of Open Access Journals (Sweden)

    A. Lingua

    2017-07-01

    Full Text Available In recent years, many studies revealed the advantages of using airborne oblique images for obtaining improved 3D city models (including façades and building footprints. Here the acquisition and use of oblique images from a low cost and open source Unmanned Aerial Vehicle (UAV for the 3D high-level-of-detail reconstruction of historical architectures is evaluated. The critical issues of such acquisitions (flight planning strategies, ground control points distribution, etc. are described. Several problems should be considered in the flight planning: best approach to cover the whole object with the minimum time of flight; visibility of vertical structures; occlusions due to the context; acquisition of all the parts of the objects (the closest and the farthest with similar resolution; suitable camera inclination, and so on. In this paper a solution is proposed in order to acquire oblique images with one only flight. The data processing was realized using Structure-from-Motion-based approach for point cloud generation using dense image-matching algorithms implemented in an open source software. The achieved results are analysed considering some check points and some reference LiDAR data. The system was tested for surveying a historical architectonical complex: the “Sacro Mo nte di Varallo Sesia” in north-west of Italy. This study demonstrates that the use of oblique images acquired from a low cost UAV system and processed through an open source software is an effective methodology to survey cultural heritage, characterized by limited accessibility, need for detail and rapidity of the acquisition phase, and often reduced budgets.

  17. Stereographic images acquired with gamma rays and thermal neutron radiography

    International Nuclear Information System (INIS)

    Souza, Maria Ines Silvani; Almeida, Gevaldo L. de; Furieri, Rosanne C.; Lopes, Ricardo T.

    2011-01-01

    Full text: The inner structure of an object, which should not be submitted to an invasive assay, can only be perceived by using a suitable technique in order to render it transparent. A widely employed technique for this purpose involves the using of a radiation capable to pass through the object, collecting the transmitted radiation by a proper device, which furnishes a radiographic attenuation map of the object. This map, however, does not display the spatial distribution of the inner components of the object, but a convoluted view for each specific attitude of the object with regard to the set beam-detector. A 3D tomographic approach would show that distribution but it would demand a large number of projections requiring special equipment and software, not always available or affordable. In some circumstances however, a 3D tomography can be replaced by a stereographic view of the object under inspection, as done in this work, where instead of tens of radiographic projections, only two of them taken at suitable object attitudes are employed. Once acquired, these projections are properly processed and observed through a red and green eyeglass. For monochromatic images, this methodology requires the transformation of the black and white radiographs into red and white and green and white ones, which are afterwards merged to yield a single image. All the process is carried out with the software Image J . In this work, the Argonauta reactor at the Instituto de Engenharia Nuclear in Rio de Janeiro has been used as a source of thermal neutrons to acquire the neutron radiographic images, as well as to produce 198 Au sources employed in the acquisition of gamma-ray radiographic ones. X-ray or neutron-sensitive imaging plates have been used as detector, which after exposure were developed by a reader using a 0.5μm-diameter laser beam. (author)

  18. Method to acquire regions of fruit, branch and leaf from image of red apple in orchard

    Science.gov (United States)

    Lv, Jidong; Xu, Liming

    2017-07-01

    This work proposed a method to acquire regions of fruit, branch and leaf from red apple image in orchard. To acquire fruit image, R-G image was extracted from the RGB image for corrosive working, hole filling, subregion removal, expansive working and opening operation in order. Finally, fruit image was acquired by threshold segmentation. To acquire leaf image, fruit image was subtracted from RGB image before extracting 2G-R-B image. Then, leaf image was acquired by subregion removal and threshold segmentation. To acquire branch image, dynamic threshold segmentation was conducted in the R-G image. Then, the segmented image was added to fruit image to acquire adding fruit image which was subtracted from RGB image with leaf image. Finally, branch image was acquired by opening operation, subregion removal and threshold segmentation after extracting the R-G image from the subtracting image. Compared with previous methods, more complete image of fruit, leaf and branch can be acquired from red apple image with this method.

  19. Radionuclide brain imaging in acquired immunodeficiency syndrome (AIDS)

    International Nuclear Information System (INIS)

    Costa, D.C.; Gacinovic, S.; Miller, R.F.

    1995-01-01

    Infection with the Human Immunodeficiency Virus type 1 (HIV-1) may produce a variety of central nervous system (CNS) symptoms and signs. CNS involvement in patients with the Acquired Immunodeficiency Syndrome (AIDS) includes AIDS dementia complex or HIV-1 associated cognitive/motor complex (widely known as HIV encephalopathy), progressive multifocal leucoencephalopathy (PML), opportunistic infections such as Toxoplasma gondii, TB, Cryptococcus and infiltration by non-Hodgkin's B cell lymphoma. High resolution structural imaging investigations, either X-ray Computed Tomography (CT scan) or Magnetic Resonance Imaging (MRI) have contributed to the understanding and definition of cerebral damage caused by HIV encephalopathy. Atrophy and mainly high signal scattered white matter abnormalities are commonly seen with MRI. PML produces focal white matter high signal abnormalities due to multiple foci of demyelination. However, using structural imaging techniques there are no reliable parameters to distinguish focal lesions due to opportunistic infection (Toxoplasma gondii abscess) from neoplasm (lymphoma infiltration). It is studied the use of radionuclide brain imaging techniques in the investigation of HIV infected patients. Brain perfusion Single Photon Emission Tomography (SPET), neuroreceptor and Positron Emission Tomography (PET) studies are reviewed. Greater emphasis is put on the potential of some radiopharmaceuticals, considered to be brain tumour markers, to distinguish intracerebral lymphoma infiltration from Toxoplasma infection. SPET with 201 Tl using quantification (tumour to non-tumour radioactivity ratios) appears a very promising technique to identify intracerebral lymphoma

  20. Extracting flat-field images from scene-based image sequences using phase correlation

    Energy Technology Data Exchange (ETDEWEB)

    Caron, James N., E-mail: Caron@RSImd.com [Research Support Instruments, 4325-B Forbes Boulevard, Lanham, Maryland 20706 (United States); Montes, Marcos J. [Naval Research Laboratory, Code 7231, 4555 Overlook Avenue, SW, Washington, DC 20375 (United States); Obermark, Jerome L. [Naval Research Laboratory, Code 8231, 4555 Overlook Avenue, SW, Washington, DC 20375 (United States)

    2016-06-15

    Flat-field image processing is an essential step in producing high-quality and radiometrically calibrated images. Flat-fielding corrects for variations in the gain of focal plane array electronics and unequal illumination from the system optics. Typically, a flat-field image is captured by imaging a radiometrically uniform surface. The flat-field image is normalized and removed from the images. There are circumstances, such as with remote sensing, where a flat-field image cannot be acquired in this manner. For these cases, we developed a phase-correlation method that allows the extraction of an effective flat-field image from a sequence of scene-based displaced images. The method uses sub-pixel phase correlation image registration to align the sequence to estimate the static scene. The scene is removed from sequence producing a sequence of misaligned flat-field images. An average flat-field image is derived from the realigned flat-field sequence.

  1. An image-guided tool to prevent hospital acquired infections

    Science.gov (United States)

    Nagy, Melinda; Szilágyi, László; Lehotsky, Ákos; Haidegger, Tamás; Benyó, Balázs

    2011-03-01

    Hospital Acquired Infections (HAI) represent the fourth leading cause of death in the United States, and claims hundreds of thousands of lives annually in the rest of the world. This paper presents a novel low-cost mobile device|called Stery-Hand|that helps to avoid HAI by improving hand hygiene control through providing an objective evaluation of the quality of hand washing. The use of the system is intuitive: having performed hand washing with a soap mixed with UV re ective powder, the skin appears brighter in UV illumination on the disinfected surfaces. Washed hands are inserted into the Stery-Hand box, where a digital image is taken under UV lighting. Automated image processing algorithms are employed in three steps to evaluate the quality of hand washing. First, the contour of the hand is extracted in order to distinguish the hand from the background. Next, a semi-supervised clustering algorithm classies the pixels of the hand into three groups, corresponding to clean, partially clean and dirty areas. The clustering algorithm is derived from the histogram-based quick fuzzy c-means approach, using a priori information extracted from reference images, evaluated by experts. Finally, the identied areas are adjusted to suppress shading eects, and quantied in order to give a verdict on hand disinfection quality. The proposed methodology was validated through tests using hundreds of images recorded in our laboratory. The proposed system was found robust and accurate, producing correct estimation for over 98% of the test cases. Stery-Hand may be employed in general practice, and it may also serve educational purposes.

  2. Left Ventricular Function Evaluation on a 3T MR Scanner with Parallel RF Transmission Technique: Prospective Comparison of Cine Sequences Acquired before and after Gadolinium Injection.

    Science.gov (United States)

    Caspar, Thibault; Schultz, Anthony; Schaeffer, Mickaël; Labani, Aïssam; Jeung, Mi-Young; Jurgens, Paul Thomas; El Ghannudi, Soraya; Roy, Catherine; Ohana, Mickaël

    To compare cine MR b-TFE sequences acquired before and after gadolinium injection, on a 3T scanner with a parallel RF transmission technique in order to potentially improve scanning time efficiency when evaluating LV function. 25 consecutive patients scheduled for a cardiac MRI were prospectively included and had their b-TFE cine sequences acquired before and right after gadobutrol injection. Images were assessed qualitatively (overall image quality, LV edge sharpness, artifacts and LV wall motion) and quantitatively with measurement of LVEF, LV mass, and telediastolic volume and contrast-to-noise ratio (CNR) between the myocardium and the cardiac chamber. Statistical analysis was conducted using a Bayesian paradigm. No difference was found before or after injection for the LVEF, LV mass and telediastolic volume evaluations. Overall image quality and CNR were significantly lower after injection (estimated coefficient cine after > cine before gadolinium: -1.75 CI = [-3.78;-0.0305], prob(coef>0) = 0% and -0.23 CI = [-0.49;0.04], prob(coef>0) = 4%) respectively), but this decrease did not affect the visual assessment of LV wall motion (cine after > cine before gadolinium: -1.46 CI = [-4.72;1.13], prob(coef>0) = 15%). In 3T cardiac MRI acquired with parallel RF transmission technique, qualitative and quantitative assessment of LV function can reliably be performed with cine sequences acquired after gadolinium injection, despite a significant decrease in the CNR and the overall image quality.

  3. Post-contrast T1-weighted sequences in pediatric abdominal imaging: comparative analysis of three different sequences and imaging approach

    Energy Technology Data Exchange (ETDEWEB)

    Roque, Andreia; Ramalho, Miguel; AlObaidy, Mamdoh; Heredia, Vasco; Burke, Lauren M.; De Campos, Rafael O.P.; Semelka, Richard C. [University of North Carolina at Chapel Hill, Department of Radiology, Chapel Hill, NC (United States)

    2014-10-15

    Post-contrast T1-weighted imaging is an essential component of a comprehensive pediatric abdominopelvic MR examination. However, consistent good image quality is challenging, as respiratory motion in sedated children can substantially degrade the image quality. To compare the image quality of three different post-contrast T1-weighted imaging techniques - standard three-dimensional gradient-echo (3-D-GRE), magnetization-prepared gradient-recall echo (MP-GRE) and 3-D-GRE with radial data sampling (radial 3-D-GRE) - acquired in pediatric patients younger than 5 years of age. Sixty consecutive exams performed in 51 patients (23 females, 28 males; mean age 2.5 ± 1.4 years) constituted the final study population. Thirty-nine scans were performed at 3 T and 21 scans were performed at 1.5 T. Two different reviewers independently and blindly qualitatively evaluated all sequences to determine image quality and extent of artifacts. MP-GRE and radial 3-D-GRE sequences had the least respiratory motion (P < 0.0001). Standard 3-D-GRE sequences displayed the lowest average score ratings in hepatic and pancreatic edge definition, hepatic vessel clarity and overall image quality. Radial 3-D-GRE sequences showed the highest scores ratings in overall image quality. Our preliminary results support the preference of fat-suppressed radial 3-D-GRE as the best post-contrast T1-weighted imaging approach for patients under the age of 5 years, when dynamic imaging is not essential. (orig.)

  4. Minimum TE gradient-recalled phosphorus imaging sequence on a whole-body imager

    International Nuclear Information System (INIS)

    Listerud, J.; Lenkinski, R.E.; Axel, L.

    1989-01-01

    To define the lower limits of spatial resolution in gradient-recalled echo phosphorus studies at 1.5 T, the authors have implemented a phosphorus gradient-recalled imaging sequence on the Signa imager. All gradient ramps for the section-selective rephasing lobe, the phase-encoding pulse, and the dephasing pulse of the frequency-encoding gradient are slowed at the maximal rate. Consequently, with a field of view of 24 cm, an in-plane resolution of 3 cm, an echo appropriately offset, an RF bandwidth of 1.2 KHz, and a section thickness of 5 cm, the echo time may be reduced to 1.35 msec. The reconstruction algorithm has been modified to support oversampled data of low spatial resolution appropriate for phosphorus imaging. The sequence will acquire H-1 images and supports the automatic and manual prescan features of the commercial instrument. To facilitate setup in the phosphorus imaging mode the sequence supports the product spectroscopic mode with a DRESS (depth recalled surface coil spectroscopy) sequence and a section profile sequence for appropriate shimming, receiver characteristics, and averaging requirements. The suitability for adaptation of this sequence to three-dimensional chemical shift imaging is discussed

  5. Image correlation method for DNA sequence alignment.

    Science.gov (United States)

    Curilem Saldías, Millaray; Villarroel Sassarini, Felipe; Muñoz Poblete, Carlos; Vargas Vásquez, Asticio; Maureira Butler, Iván

    2012-01-01

    The complexity of searches and the volume of genomic data make sequence alignment one of bioinformatics most active research areas. New alignment approaches have incorporated digital signal processing techniques. Among these, correlation methods are highly sensitive. This paper proposes a novel sequence alignment method based on 2-dimensional images, where each nucleic acid base is represented as a fixed gray intensity pixel. Query and known database sequences are coded to their pixel representation and sequence alignment is handled as object recognition in a scene problem. Query and database become object and scene, respectively. An image correlation process is carried out in order to search for the best match between them. Given that this procedure can be implemented in an optical correlator, the correlation could eventually be accomplished at light speed. This paper shows an initial research stage where results were "digitally" obtained by simulating an optical correlation of DNA sequences represented as images. A total of 303 queries (variable lengths from 50 to 4500 base pairs) and 100 scenes represented by 100 x 100 images each (in total, one million base pair database) were considered for the image correlation analysis. The results showed that correlations reached very high sensitivity (99.01%), specificity (98.99%) and outperformed BLAST when mutation numbers increased. However, digital correlation processes were hundred times slower than BLAST. We are currently starting an initiative to evaluate the correlation speed process of a real experimental optical correlator. By doing this, we expect to fully exploit optical correlation light properties. As the optical correlator works jointly with the computer, digital algorithms should also be optimized. The results presented in this paper are encouraging and support the study of image correlation methods on sequence alignment.

  6. Digital image sequence processing, compression, and analysis

    CERN Document Server

    Reed, Todd R

    2004-01-01

    IntroductionTodd R. ReedCONTENT-BASED IMAGE SEQUENCE REPRESENTATIONPedro M. Q. Aguiar, Radu S. Jasinschi, José M. F. Moura, andCharnchai PluempitiwiriyawejTHE COMPUTATION OF MOTIONChristoph Stiller, Sören Kammel, Jan Horn, and Thao DangMOTION ANALYSIS AND DISPLACEMENT ESTIMATION IN THE FREQUENCY DOMAINLuca Lucchese and Guido Maria CortelazzoQUALITY OF SERVICE ASSESSMENT IN NEW GENERATION WIRELESS VIDEO COMMUNICATIONSGaetano GiuntaERROR CONCEALMENT IN DIGITAL VIDEOFrancesco G.B. De NataleIMAGE SEQUENCE RESTORATION: A WIDER PERSPECTIVEAnil KokaramVIDEO SUMMARIZATIONCuneyt M. Taskiran and Edward

  7. Statistical processing of large image sequences.

    Science.gov (United States)

    Khellah, F; Fieguth, P; Murray, M J; Allen, M

    2005-01-01

    The dynamic estimation of large-scale stochastic image sequences, as frequently encountered in remote sensing, is important in a variety of scientific applications. However, the size of such images makes conventional dynamic estimation methods, for example, the Kalman and related filters, impractical. In this paper, we present an approach that emulates the Kalman filter, but with considerably reduced computational and storage requirements. Our approach is illustrated in the context of a 512 x 512 image sequence of ocean surface temperature. The static estimation step, the primary contribution here, uses a mixture of stationary models to accurately mimic the effect of a nonstationary prior, simplifying both computational complexity and modeling. Our approach provides an efficient, stable, positive-definite model which is consistent with the given correlation structure. Thus, the methods of this paper may find application in modeling and single-frame estimation.

  8. Wavelet-based de-noising algorithm for images acquired with parallel magnetic resonance imaging (MRI)

    International Nuclear Information System (INIS)

    Delakis, Ioannis; Hammad, Omer; Kitney, Richard I

    2007-01-01

    Wavelet-based de-noising has been shown to improve image signal-to-noise ratio in magnetic resonance imaging (MRI) while maintaining spatial resolution. Wavelet-based de-noising techniques typically implemented in MRI require that noise displays uniform spatial distribution. However, images acquired with parallel MRI have spatially varying noise levels. In this work, a new algorithm for filtering images with parallel MRI is presented. The proposed algorithm extracts the edges from the original image and then generates a noise map from the wavelet coefficients at finer scales. The noise map is zeroed at locations where edges have been detected and directional analysis is also used to calculate noise in regions of low-contrast edges that may not have been detected. The new methodology was applied on phantom and brain images and compared with other applicable de-noising techniques. The performance of the proposed algorithm was shown to be comparable with other techniques in central areas of the images, where noise levels are high. In addition, finer details and edges were maintained in peripheral areas, where noise levels are low. The proposed methodology is fully automated and can be applied on final reconstructed images without requiring sensitivity profiles or noise matrices of the receiver coils, therefore making it suitable for implementation in a clinical MRI setting

  9. An Imaging And Graphics Workstation For Image Sequence Analysis

    Science.gov (United States)

    Mostafavi, Hassan

    1990-01-01

    This paper describes an application-specific engineering workstation designed and developed to analyze imagery sequences from a variety of sources. The system combines the software and hardware environment of the modern graphic-oriented workstations with the digital image acquisition, processing and display techniques. The objective is to achieve automation and high throughput for many data reduction tasks involving metric studies of image sequences. The applications of such an automated data reduction tool include analysis of the trajectory and attitude of aircraft, missile, stores and other flying objects in various flight regimes including launch and separation as well as regular flight maneuvers. The workstation can also be used in an on-line or off-line mode to study three-dimensional motion of aircraft models in simulated flight conditions such as wind tunnels. The system's key features are: 1) Acquisition and storage of image sequences by digitizing real-time video or frames from a film strip; 2) computer-controlled movie loop playback, slow motion and freeze frame display combined with digital image sharpening, noise reduction, contrast enhancement and interactive image magnification; 3) multiple leading edge tracking in addition to object centroids at up to 60 fields per second from both live input video or a stored image sequence; 4) automatic and manual field-of-view and spatial calibration; 5) image sequence data base generation and management, including the measurement data products; 6) off-line analysis software for trajectory plotting and statistical analysis; 7) model-based estimation and tracking of object attitude angles; and 8) interface to a variety of video players and film transport sub-systems.

  10. Imaging features of mycobacterium in patients with acquired immunodeficiency syndrome

    International Nuclear Information System (INIS)

    Yang Jun; Sun Yue; Wei Liangui; Xu Yunliang; Li Xingwang

    2013-01-01

    Objective: To analyze the imaging features of mycobacterium in AIDS patients. Methods: Twenty-three cases of mycobacterium tuberculosis and 13 patients of non-tuberculous mycobacteria were proved etiologically and included in this study. All patients underwent X-ray and CT examinations, imaging data were analyzed and compared. Results: The imaging findings of mycobacterium tuberculosis in AIDS patients included consolidation (n = 11), pleural effusion (n = 11), mediastinal lymphadenopathy (n = 11). Pulmonary lesions were always diffuse distribution, and 14 patients of extrapulmonary tuberculosis were found. Pulmonary lesions in non-tuberculous mycobacteria tend to be circumscribed. Conclusions: Non-tuberculous mycobacterial infection in AIDS patients is more common and usually combined with other infections. Imaging features are atypical. (authors)

  11. Acquired image quality in digital industrial radiographic equipments

    International Nuclear Information System (INIS)

    Oliveira, Cristiane de Queiroz; Lopes, Ricardo Tadeu; Oliveira, Davi F.

    2008-01-01

    The computerized radiographic application in the industrial area is a recent event. The imaging plate is the equipment used as imaging receiver during the exposition radiographic technique, which consists of a flexible photostimulable phosphor screen, capable of storing the photons energy of the incident X and γ rays and of a reading unit which uses a laser device to stimulate a visible light. As two types of phosphor screen are manufactured, one for general use (General Plate - GP) and another one for specific using (High Resolution-HR), one of the objectives of this study was to evaluate the spatial resolution capability in both plates using the Kodak equipment. Furthermore, equipment from different makers, Kodak and General Electric Company - GE, were compared. Two phosphor screen HR were used as the main objective of this study. Imaging Quality Indicators - IQI were used to evaluate the spatial resolution of the images in accordance with ASME and DIN standard. The results show that after evaluating the GP and HR Kodak plates, the HR plate was capable of showing a larger resolution of details. However, after evaluating the performance of the HR Kodak plate and GE plate, over the same acquisition condition and with the same size of the laser focal set of 87 μm, the results show a superiority in the GE equipment used for industrial radiographic, mainly for processed images in each specific ambient of digital processing and its performance in meeting satisfactorily the ASME code and the DIN standard. (author)

  12. Study of recognizing multiple persons' complicated hand gestures from the video sequence acquired by a moving camera

    Science.gov (United States)

    Dan, Luo; Ohya, Jun

    2010-02-01

    Recognizing hand gestures from the video sequence acquired by a dynamic camera could be a useful interface between humans and mobile robots. We develop a state based approach to extract and recognize hand gestures from moving camera images. We improved Human-Following Local Coordinate (HFLC) System, a very simple and stable method for extracting hand motion trajectories, which is obtained from the located human face, body part and hand blob changing factor. Condensation algorithm and PCA-based algorithm was performed to recognize extracted hand trajectories. In last research, this Condensation Algorithm based method only applied for one person's hand gestures. In this paper, we propose a principal component analysis (PCA) based approach to improve the recognition accuracy. For further improvement, temporal changes in the observed hand area changing factor are utilized as new image features to be stored in the database after being analyzed by PCA. Every hand gesture trajectory in the database is classified into either one hand gesture categories, two hand gesture categories, or temporal changes in hand blob changes. We demonstrate the effectiveness of the proposed method by conducting experiments on 45 kinds of sign language based Japanese and American Sign Language gestures obtained from 5 people. Our experimental recognition results show better performance is obtained by PCA based approach than the Condensation algorithm based method.

  13. Real-time SPARSE-SENSE cardiac cine MR imaging: optimization of image reconstruction and sequence validation.

    Science.gov (United States)

    Goebel, Juliane; Nensa, Felix; Bomas, Bettina; Schemuth, Haemi P; Maderwald, Stefan; Gratz, Marcel; Quick, Harald H; Schlosser, Thomas; Nassenstein, Kai

    2016-12-01

    Improved real-time cardiac magnetic resonance (CMR) sequences have currently been introduced, but so far only limited practical experience exists. This study aimed at image reconstruction optimization and clinical validation of a new highly accelerated real-time cine SPARSE-SENSE sequence. Left ventricular (LV) short-axis stacks of a real-time free-breathing SPARSE-SENSE sequence with high spatiotemporal resolution and of a standard segmented cine SSFP sequence were acquired at 1.5 T in 11 volunteers and 15 patients. To determine the optimal iterations, all volunteers' SPARSE-SENSE images were reconstructed using 10-200 iterations, and contrast ratios, image entropies, and reconstruction times were assessed. Subsequently, the patients' SPARSE-SENSE images were reconstructed with the clinically optimal iterations. LV volumetric values were evaluated and compared between both sequences. Sufficient image quality and acceptable reconstruction times were achieved when using 80 iterations. Bland-Altman plots and Passing-Bablok regression showed good agreement for all volumetric parameters. 80 iterations are recommended for iterative SPARSE-SENSE image reconstruction in clinical routine. Real-time cine SPARSE-SENSE yielded comparable volumetric results as the current standard SSFP sequence. Due to its intrinsic low image acquisition times, real-time cine SPARSE-SENSE imaging with iterative image reconstruction seems to be an attractive alternative for LV function analysis. • A highly accelerated real-time CMR sequence using SPARSE-SENSE was evaluated. • SPARSE-SENSE allows free breathing in real-time cardiac cine imaging. • For clinically optimal SPARSE-SENSE image reconstruction, 80 iterations are recommended. • Real-time SPARSE-SENSE imaging yielded comparable volumetric results as the reference SSFP sequence. • The fast SPARSE-SENSE sequence is an attractive alternative to standard SSFP sequences.

  14. Enhanced spatio-temporal alignment of plantar pressure image sequences using B-splines.

    Science.gov (United States)

    Oliveira, Francisco P M; Tavares, João Manuel R S

    2013-03-01

    This article presents an enhanced methodology to align plantar pressure image sequences simultaneously in time and space. The temporal alignment of the sequences is accomplished using B-splines in the time modeling, and the spatial alignment can be attained using several geometric transformation models. The methodology was tested on a dataset of 156 real plantar pressure image sequences (3 sequences for each foot of the 26 subjects) that was acquired using a common commercial plate during barefoot walking. In the alignment of image sequences that were synthetically deformed both in time and space, an outstanding accuracy was achieved with the cubic B-splines. This accuracy was significantly better (p align real image sequences with unknown transformation involved, the alignment based on cubic B-splines also achieved superior results than our previous methodology (p alignment on the dynamic center of pressure (COP) displacement was also assessed by computing the intraclass correlation coefficients (ICC) before and after the temporal alignment of the three image sequence trials of each foot of the associated subject at six time instants. The results showed that, generally, the ICCs related to the medio-lateral COP displacement were greater when the sequences were temporally aligned than the ICCs of the original sequences. Based on the experimental findings, one can conclude that the cubic B-splines are a remarkable solution for the temporal alignment of plantar pressure image sequences. These findings also show that the temporal alignment can increase the consistency of the COP displacement on related acquired plantar pressure image sequences.

  15. RF Device for Acquiring Images of the Human Body

    Science.gov (United States)

    Gaier, Todd C.; McGrath, William R.

    2010-01-01

    A safe, non-invasive method for forming images through clothing of large groups of people, in order to search for concealed weapons either made of metal or not, has been developed. A millimeter wavelength scanner designed in a unique, ring-shaped configuration can obtain a full 360 image of the body with a resolution of less than a millimeter in only a few seconds. Millimeter waves readily penetrate normal clothing, but are highly reflected by the human body and concealed objects. Millimeter wave signals are nonionizing and are harmless to human tissues when used at low power levels. The imager (see figure) consists of a thin base that supports a small-diameter vertical post about 7 ft (=2.13 m) tall. Attached to the post is a square-shaped ring 2 in. (=5 cm) wide and 3 ft (=91 cm) on a side. The ring is oriented horizontally, and is supported halfway along one side by a connection to a linear bearing on the vertical post. A planar RF circuit board is mounted to the inside of each side of the ring. Each circuit board contains an array of 30 receivers, one transmitter, and digitization electronics. Each array element has a printed-circuit patch antenna coupled to a pair of mixers by a 90 coupler. The mixers receive a reference local oscillator signal to a subharmonic of the transmitter frequency. A single local oscillator line feeds all 30 receivers on the board. The resulting MHz IF signals are amplified and carried to the edge of the board where they are demodulated and digitized. The transmitted signal is derived from the local oscillator at a frequency offset determined by a crystal oscillator. One antenna centrally located on each side of the square ring provides the source illumination power. The total transmitted power is less than 100 mW, resulting in an exposure level that is completely safe to humans. The output signals from all four circuit boards are fed via serial connection to a data processing computer. The computer processes the approximately 1-MB

  16. IT Infrastructure to Support the Secondary Use of Routinely Acquired Clinical Imaging Data for Research

    NARCIS (Netherlands)

    K.Y.E. Leung (Esther); F. van der Lijn (Fedde); H.A. Vrooman (Henri); M.C.J.M. Sturkenboom (Miriam); W.J. Niessen (Wiro)

    2014-01-01

    textabstractWe propose an infrastructure for the automated anonymization, extraction and processing of image data stored in clinical data repositories to make routinely acquired imaging data available for research purposes. The automated system, which was tested in the context of analyzing routinely

  17. Evaluation of the reconstruction of image acquired from CT simulator to reduce metal artifact

    International Nuclear Information System (INIS)

    Choi, Ji Hun; Park, Jin Hong; Choi, Byung Don; Won, Hui Su; Chang, Nam Jun; Goo, Jang Hyun; Hong, Joo Wan

    2014-01-01

    This study presents the usefulness assessment of metal artifact reduction for orthopedic implants(O-MAR) to decrease metal artifacts from materials with high density when acquired CT images. By CT simulator, original CT images were acquired from Gammex and Rando phantom and those phantoms inserted with high density materials were scanned for other CT images with metal artifacts and then O-MAR was applied to those images, respectively. To evaluate CT images using Gammex phantom, 5 regions of interest(ROIs) were placed at 5 organs and 3 ROIs were set up at points affected by artifacts. The averages of standard deviation(SD) and CT numbers were compared with a plan using original image. For assessment of variations in dose of tissue around materials with high density, the volume of a cylindrical shape was designed at 3 places in images acquired from Rando phantom by Eclipse. With 6 MV, 7-fields, 15x15cm 2 and 100 cGy per fraction, treatment planning was created and the mean dose were compared with a plan using original image. In the test with the Gammex phantom, CT numbers had a few difference at established points and especially 3 points affected by artifacts had most of the same figures. In the case of O-MAR image, the more reduction in SD appeared at all of 8 points than non O-MAR image. In the test using the Rando Phantom, the variations in dose of tissue around high density materials had a few difference between original CT image and CT image with O-MAR. The CT images using O-MAR were acquired clearly at the boundary of tissue around high density materials and applying O-MAR was useful for correcting CT numbers

  18. Iris recognition: on the segmentation of degraded images acquired in the visible wavelength.

    Science.gov (United States)

    Proença, Hugo

    2010-08-01

    Iris recognition imaging constraints are receiving increasing attention. There are several proposals to develop systems that operate in the visible wavelength and in less constrained environments. These imaging conditions engender acquired noisy artifacts that lead to severely degraded images, making iris segmentation a major issue. Having observed that existing iris segmentation methods tend to fail in these challenging conditions, we present a segmentation method that can handle degraded images acquired in less constrained conditions. We offer the following contributions: 1) to consider the sclera the most easily distinguishable part of the eye in degraded images, 2) to propose a new type of feature that measures the proportion of sclera in each direction and is fundamental in segmenting the iris, and 3) to run the entire procedure in deterministically linear time in respect to the size of the image, making the procedure suitable for real-time applications.

  19. Kaposi sarcoma related to acquired immunodeficiency syndrome: hepatic findings on computed tomography and magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Daniel Nobrega da; Viana, Publio Cesar Cavalcante; Maciel, Rosangela Pereira; Rocha, Manoel de Souza; Gebrim, Eloisa Maria Mello Santiago [Universidade de Sao Paulo (USP), SP (Brazil). Hospital das Clinicas. Inst. de Radiologia]. E-mail: dnobrega@gmail.com

    2008-03-15

    Kaposi sarcoma is a neoplasm associated with immunosuppressive conditions, and involving blood and lymphatic vessels. It is the most frequent intrahepatic neoplasm in patients with acquired immunodeficiency syndrome. Computed tomography and magnetic resonance imaging demonstrate multiple small nodules, prominence and contrast-enhancement of periportal branches due to the presence of the neoplastic tissue. The authors report a case of a 47-year-old male patient with acquired immunodeficiency syndrome presenting disseminated Kaposi sarcoma. (author)

  20. An Approach for Unsupervised Change Detection in Multitemporal VHR Images Acquired by Different Multispectral Sensors

    Directory of Open Access Journals (Sweden)

    Yady Tatiana Solano-Correa

    2018-03-01

    Full Text Available This paper proposes an approach for the detection of changes in multitemporal Very High Resolution (VHR optical images acquired by different multispectral sensors. The proposed approach, which is inspired by a recent framework developed to support the design of change-detection systems for single-sensor VHR remote sensing images, addresses and integrates in the general approach a strategy to effectively deal with multisensor information, i.e., to perform change detection between VHR images acquired by different multispectral sensors on two dates. This is achieved by the definition of procedures for the homogenization of radiometric, spectral and geometric image properties. These procedures map images into a common feature space where the information acquired by different multispectral sensors becomes comparable across time. Although the approach is general, here we optimize it for the detection of changes in vegetation and urban areas by employing features based on linear transformations (Tasseled Caps and Orthogonal Equations, which are shown to be effective for representing the multisensor information in a homogeneous physical way irrespectively of the considered sensor. Experiments on multitemporal images acquired by different VHR satellite systems (i.e., QuickBird, WorldView-2 and GeoEye-1 confirm the effectiveness of the proposed approach.

  1. Eigenimage filtering of nuclear medicine image sequences

    International Nuclear Information System (INIS)

    Windham, J.P.; Froelich, J.W.; Abd-Allah, M.

    1985-01-01

    In many nuclear medicine imaging sequences the localization of radioactivity in organs other than the target organ interferes with imaging of the desired anatomical structure or physiological process. A filtering technique has been developed which suppresses the interfering process while enhancing the desired process. This technique requires the identification of temporal sequential signatures for both the interfering and desired processes. These signatures are placed in the form of signature vectors. Signature matrices, M/sub D/ and M/sub U/, are formed by taking the outer product expansion of the temporal signature vectors for the desired and interfering processes respectively. By using the transformation from the simultaneous diagonalization of these two signature matrices a weighting vector is obtained. The technique is shown to maximize the projection of the desired process while minimizing the interfering process based upon an extension of Rayleigh's Principle. The technique is demonstrated for first pass renal and cardiac flow studies. This filter offers a potential for simplifying and extending the accuracy of diagnostic nuclear medicine procedures

  2. Pulse sequences for contrast-enhanced magnetic resonance imaging

    International Nuclear Information System (INIS)

    Graves, Martin J.

    2007-01-01

    The theory and application of magnetic resonance imaging (MRI) pulse sequences following the administration of an exogenous contrast agent are discussed. Pulse sequences are categorised according to the contrast agent mechanism: changes in proton density, relaxivity, magnetic susceptibility and resonant frequency shift. Applications in morphological imaging, magnetic resonance angiography, dynamic imaging and cell labelling are described. The importance of optimising the pulse sequence for each application is emphasised

  3. Artificial Intelligence In Processing A Sequence Of Time-Varying Images

    Science.gov (United States)

    Siler, W.; Tucker, D.; Buckley, J.; Hess, R. G.; Powell, V. G.

    1985-04-01

    A computer system is described for unsupervised analysis of five sets of ultrasound images of the heart. Each set consists of 24 frames taken at 33 millisecond intervals. The images are acquired in real time with computer control of the ultrasound apparatus. After acquisition the images are segmented by a sequence of image-processing programs; features are extracted and stored in a version of the Carnegie- Mellon Blackboard. Region classification is accomplished by a fuzzy logic expert system FLOPS based on OPS5. Preliminary results are given.

  4. A comparative analysis of double inversion recovery TFE and TSE sequences on carotid artery wall imaging

    International Nuclear Information System (INIS)

    Chen Jun; Di Yujin; Bu Chunqing; Zhang Yanfeng; Li Shuhua

    2012-01-01

    Objective: To analyze the characteristics of double inversion recovery (DIR) turbo field echo (TFE) and turbo spin echo (TSE) sequences and explore the value of double inversion recovery TFE sequence on carotid artery wall imaging. Patients and methods: 56 patients (32 males and 24 females, aged 31–76 years with a mean age of 53 years) were performed with DIR TFE and DIR TSE T1 weighted imaging (T1WI) sequences on carotid artery bifurcations. Image quality acquired by different techniques were evaluated and scored by two physicians. Whether there is significant difference is determined by SPSS 11.0 software. Paired-samples t test was used for statistics. Results: There was no significant difference in the image quality scores between two sequences (t = 0.880, P = 0.383 > 0.05). Conclusions: DIR TFE sequence has short scanning time and high spatial resolution. DIR TFE sequence can be used as the preferred sequence for screening carotid atherosclerotic plaque compared with DIR TSE sequence.

  5. A New Images Hiding Scheme Based on Chaotic Sequences

    Institute of Scientific and Technical Information of China (English)

    LIU Nian-sheng; GUO Dong-hui; WU Bo-xi; Parr G

    2005-01-01

    We propose a data hidding technique in a still image. This technique is based on chaotic sequence in the transform domain of covert image. We use different chaotic random sequences multiplied by multiple sensitive images, respectively, to spread the spectrum of sensitive images. Multiple sensitive images are hidden in a covert image as a form of noise. The results of theoretical analysis and computer simulation show the new hiding technique have better properties with high security, imperceptibility and capacity for hidden information in comparison with the conventional scheme such as LSB (Least Significance Bit).

  6. Comparisons of lesion detectability in ultrasound images acquired using time-shift compensation and spatial compounding.

    Science.gov (United States)

    Lacefield, James C; Pilkington, Wayne C; Waag, Robert C

    2004-12-01

    The effects of aberration, time-shift compensation, and spatial compounding on the discrimination of positive-contrast lesions in ultrasound b-scan images are investigated using a two-dimensional (2-D) array system and tissue-mimicking phantoms. Images were acquired within an 8.8 x 12-mm2 field of view centered on one of four statistically similar 4-mm diameter spherical lesions. Each lesion was imaged in four planes offset by successive 45 degree rotations about the central scan line. Images of the lesions were acquired using conventional geometric focusing through a water path, geometric focusing through a 35-mm thick distributed aberration phantom, and time-shift compensated transmit and receive focusing through the aberration phantom. The views of each lesion were averaged to form sets of water path, aberrated, and time-shift compensated 4:1 compound images and 16:1 compound images. The contrast ratio and detectability index of each image were computed to assess lesion differentiation. In the presence of aberration representative of breast or abdominal wall tissue, time-shift compensation provided statistically significant improvements of contrast ratio but did not consistently affect the detectability index, and spatial compounding significantly increased the detectability index but did not alter the contrast ratio. Time-shift compensation and spatial compounding thus provide complementary benefits to lesion detection.

  7. Contrast-enhanced dynamic MR imaging of parasellar tumor using fast spin-echo sequence

    International Nuclear Information System (INIS)

    Kusunoki, Katsusuke; Ohue, Shiro; Ichikawa, Haruhisa; Saito, Masahiro; Sadamoto, Kazuhiko; Sakaki, Saburo; Miki, Hitoshi.

    1995-01-01

    We have applied a new dynamic MRI technique that uses a fast spin-echo sequence to parasellar tumors. This sequence has less susceptible effect and better spatial resolution than a gradient echo sequence, providing faster images than a short spin-echo sequence does. Image was obtained in the coronal or sagittal plane using a 1.5T clinical MRI system, and then, dynamic MR images were acquired every 10 to 20 sec after administration of Gd-DTPA (0.1 mmol/kg). The subjects were 12 patients (5 microadenomas, 5 macroadenomas and 2 Rathke's cleft cysts) and 5 normal volunteers. As for volunteers, the cavernous sinus, pituitary stalk and posterior pituitary gland were contrasted on the first image, followed by visualization of the proximal portion adjacent to the junction of the infundibulum and the anterior pituitary gland, and finally by contrasting the distal portion of the anterior pituitary gland. There was a difference with respect to tumor contrast between microadenomas and macroadenomas. In the case of the macroadenomas, the tumor was contrasted at the same time as, or faster than the anterior pituitary gland, while with the microadenomas the tumor was enhanced later than the anterior pituitary gland. No enhancement with contrast medium was seen in Rathke's cleft cysts. In addition, it was possible to differentiate a recurrent tumor from a piece of muscle placed at surgery since the images obtained by the fast spin-echo sequence were clearer than those obtained by gradient echo sequence. (author)

  8. Preliminary analysis of the forest health state based on multispectral images acquired by Unmanned Aerial Vehicle

    Directory of Open Access Journals (Sweden)

    Czapski Paweł

    2015-09-01

    Full Text Available The main purpose of this publication is to present the current progress of the work associated with the use of a lightweight unmanned platforms for various environmental studies. Current development in information technology, electronics and sensors miniaturisation allows mounting multispectral cameras and scanners on unmanned aerial vehicle (UAV that could only be used on board aircraft and satellites. Remote Sensing Division in the Institute of Aviation carries out innovative researches using multisensory platform and lightweight unmanned vehicle to evaluate the health state of forests in Wielkopolska province. In this paper, applicability of multispectral images analysis acquired several times during the growing season from low altitude (up to 800m is presented. We present remote sensing indicators computed by our software and common methods for assessing state of trees health. The correctness of applied methods is verified using analysis of satellite scenes acquired by Landsat 8 OLI instrument (Operational Land Imager.

  9. Safety Assessment of Advanced Imaging Sequences I: Measurements

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Rasmussen, Morten Fischer; Pihl, Michael Johannes

    2016-01-01

    intensity measurement program. The approach can measure and store data for a full imaging sequence in 3.8 to 8.2 s per spatial position. Based on Ispta, MI, and probe surface temperature, the method gives the ability to determine whether a sequence is within US FDA limits, or alternatively indicate how......A method for rapid measurement of intensities (Ispta), mechanical index (MI), and probe surface temperature for any ultrasound scanning sequence is presented. It uses the scanner’s sampling capability to give an accurate measurement of the whole imaging sequence for all emissions to yield the true...... measurement system (Onda Corporation, Sunnyvale, CA, USA). Four different sequences have been measured: a fixed focus emission, a duplex sequence containing B-mode and flow emissions, a vector flow sequence with B-mode and flow emissions in 17 directions, and finally a synthetic aperture (SA) duplex flow...

  10. Novel method to calculate pulmonary compliance images in rodents from computed tomography acquired at constant pressures

    International Nuclear Information System (INIS)

    Guerrero, Thomas; Castillo, Richard; Sanders, Kevin; Price, Roger; Komaki, Ritsuko; Cody, Dianna

    2006-01-01

    Our goal was to develop a method for generating high-resolution three-dimensional pulmonary compliance images in rodents from computed tomography (CT) images acquired at a series of constant pressures in ventilated animals. One rat and one mouse were used to demonstrate this technique. A pre-clinical GE flat panel CT scanner (maximum 31 line-pairs cm -1 resolution) was utilized for image acquisition. The thorax of each animal was imaged with breath-holds at 2, 6, 10, 14 and 18 cm H 2 O pressure in triplicate. A deformable image registration algorithm was applied to each pair of CT images to map corresponding tissue elements. Pulmonary compliance was calculated on a voxel by voxel basis using adjacent pairs of CT images. Triplicate imaging was used to estimate the measurement error of this technique. The 3D pulmonary compliance images revealed regional heterogeneity of compliance. The maximum total lung compliance measured 0.080 (±0.007) ml air per cm H 2 O per ml of lung and 0.039 (±0.004) ml air per cm H 2 O per ml of lung for the rat and mouse, respectively. In this study, we have demonstrated a unique method of quantifying regional lung compliance from 4 to 16 cm H 2 O pressure with sub-millimetre spatial resolution in rodents

  11. Logarithmic Type Image Processing Framework for Enhancing Photographs Acquired in Extreme Lighting

    Directory of Open Access Journals (Sweden)

    FLOREA, C.

    2013-05-01

    Full Text Available The Logarithmic Type Image Processing (LTIP tools are mathematical models that were constructed for the representation and processing of gray tones images. By careful redefinition of the fundamental operations, namely addition and scalar multiplication, a set of mathematical properties are achieved. Here we propose the extension of LTIP models by a novel parameterization rule that ensures preservation of the required cone space structure. To prove the usability of the proposed extension we present an application for low-light image enhancement in images acquired with digital still camera. The closing property of the named model facilitates similarity with human visual system and digital camera processing pipeline, thus leading to superior behavior when compared with state of the art methods.

  12. Motion Detection in Ultrasound Image-Sequences Using Tensor Voting

    Science.gov (United States)

    Inba, Masafumi; Yanagida, Hirotaka; Tamura, Yasutaka

    2008-05-01

    Motion detection in ultrasound image sequences using tensor voting is described. We have been developing an ultrasound imaging system adopting a combination of coded excitation and synthetic aperture focusing techniques. In our method, frame rate of the system at distance of 150 mm reaches 5000 frame/s. Sparse array and short duration coded ultrasound signals are used for high-speed data acquisition. However, many artifacts appear in the reconstructed image sequences because of the incompleteness of the transmitted code. To reduce the artifacts, we have examined the application of tensor voting to the imaging method which adopts both coded excitation and synthetic aperture techniques. In this study, the basis of applying tensor voting and the motion detection method to ultrasound images is derived. It was confirmed that velocity detection and feature enhancement are possible using tensor voting in the time and space of simulated ultrasound three-dimensional image sequences.

  13. Fat suppression in MR imaging with binomial pulse sequences

    International Nuclear Information System (INIS)

    Baudovin, C.J.; Bryant, D.J.; Bydder, G.M.; Young, I.R.

    1989-01-01

    This paper reports on a study to develop pulse sequences allowing suppression of fat signal on MR images without eliminating signal from other tissues with short T1. They have developed such a technique involving selective excitation of protons in water, based on a binomial pulse sequence. Imaging is performed at 0.15 T. Careful shimming is performed to maximize separation of fat and water peaks. A spin-echo 1,500/80 sequence is used, employing 90 degrees pulse with transit frequency optimized for water with null excitation of 20 H offset, followed by a section-selective 180 degrees pulse. With use of the binomial sequence for imagining, reduction in fat signal is seen on images of the pelvis and legs of volunteers. Patient studies show dramatic improvement in visualization of prostatic carcinoma compared with standard sequences

  14. Image encryption using random sequence generated from generalized information domain

    International Nuclear Information System (INIS)

    Zhang Xia-Yan; Wu Jie-Hua; Zhang Guo-Ji; Li Xuan; Ren Ya-Zhou

    2016-01-01

    A novel image encryption method based on the random sequence generated from the generalized information domain and permutation–diffusion architecture is proposed. The random sequence is generated by reconstruction from the generalized information file and discrete trajectory extraction from the data stream. The trajectory address sequence is used to generate a P-box to shuffle the plain image while random sequences are treated as keystreams. A new factor called drift factor is employed to accelerate and enhance the performance of the random sequence generator. An initial value is introduced to make the encryption method an approximately one-time pad. Experimental results show that the random sequences pass the NIST statistical test with a high ratio and extensive analysis demonstrates that the new encryption scheme has superior security. (paper)

  15. Image ranking in video sequences using pairwise image comparisons and temporal smoothing

    CSIR Research Space (South Africa)

    Burke, Michael

    2016-12-01

    Full Text Available The ability to predict the importance of an image is highly desirable in computer vision. This work introduces an image ranking scheme suitable for use in video or image sequences. Pairwise image comparisons are used to determine image ‘interest...

  16. Design and DSP implementation of star image acquisition and star point fast acquiring and tracking

    Science.gov (United States)

    Zhou, Guohui; Wang, Xiaodong; Hao, Zhihang

    2006-02-01

    Star sensor is a special high accuracy photoelectric sensor. Attitude acquisition time is an important function index of star sensor. In this paper, the design target is to acquire 10 samples per second dynamic performance. On the basis of analyzing CCD signals timing and star image processing, a new design and a special parallel architecture for improving star image processing are presented in this paper. In the design, the operation moving the data in expanded windows including the star to the on-chip memory of DSP is arranged in the invalid period of CCD frame signal. During the CCD saving the star image to memory, DSP processes the data in the on-chip memory. This parallelism greatly improves the efficiency of processing. The scheme proposed here results in enormous savings of memory normally required. In the scheme, DSP HOLD mode and CPLD technology are used to make a shared memory between CCD and DSP. The efficiency of processing is discussed in numerical tests. Only in 3.5ms is acquired the five lightest stars in the star acquisition stage. In 43us, the data in five expanded windows including stars are moved into the internal memory of DSP, and in 1.6ms, five star coordinates are achieved in the star tracking stage.

  17. Artifact free T2{sup *}-weighted imaging at high spatial resolution using segmented EPI sequences

    Energy Technology Data Exchange (ETDEWEB)

    Heiler, Patrick Michael; Schad, Lothar Rudi [Heidelberg Univ., Mannheim (Germany). Computer Assisted Clinical Medicine; Schmitter, Sebastian [German Cancer Research Center, Heidelberg (Germany). Dept. of Medical Physics in Radiology

    2010-07-01

    The aim of this work was the development of novel measurement techniques that acquire high resolution T2{sup *}-weighted datasets in measurement times as short as possible without suffering from noticeable blurring and ghosting artifacts. Therefore, two new measurement techniques were developed that acquire a smoother k-space than generic multi shot echo planar imaging sequences. One is based on the principle of echo train shifting, the other on the reversed gradient method. Simulations and phantom measurements demonstrate that echo train shifting works properly and reduces artifacts in multi shot echo planar imaging. For maximum SNR-efficiency this technique was further improved by adding a second contrast. Both contrasts can be acquired within a prolongation in measurement time by a factor of 1.5, leading to an SNR increase by approximately {radical}2. Furthermore it is demonstrated that the reversed gradient method remarkably reduces artifacts caused by a discontinuous k-space weighting. Assuming sequence parameters as feasible for fMRI experiments, artifact free T2{sup *}-weighted images with a matrix size of 256 x 256 leading to an in-plane resolution in the submillimeter range can be obtained in about 2 s per slice. (orig.)

  18. Artifact free T2*-weighted imaging at high spatial resolution using segmented EPI sequences

    International Nuclear Information System (INIS)

    Heiler, Patrick Michael; Schad, Lothar Rudi; Schmitter, Sebastian

    2010-01-01

    The aim of this work was the development of novel measurement techniques that acquire high resolution T2 * -weighted datasets in measurement times as short as possible without suffering from noticeable blurring and ghosting artifacts. Therefore, two new measurement techniques were developed that acquire a smoother k-space than generic multi shot echo planar imaging sequences. One is based on the principle of echo train shifting, the other on the reversed gradient method. Simulations and phantom measurements demonstrate that echo train shifting works properly and reduces artifacts in multi shot echo planar imaging. For maximum SNR-efficiency this technique was further improved by adding a second contrast. Both contrasts can be acquired within a prolongation in measurement time by a factor of 1.5, leading to an SNR increase by approximately √2. Furthermore it is demonstrated that the reversed gradient method remarkably reduces artifacts caused by a discontinuous k-space weighting. Assuming sequence parameters as feasible for fMRI experiments, artifact free T2 * -weighted images with a matrix size of 256 x 256 leading to an in-plane resolution in the submillimeter range can be obtained in about 2 s per slice. (orig.)

  19. CT and MR imaging evaluation of the inherited and prenatally acquired migrational disorders of the brain

    International Nuclear Information System (INIS)

    Byrd, S.E.; Osborn, R.E.; Naidich, T.P.; Bohan, T.P.

    1987-01-01

    The migrational disorders are a rare group of congenital malformations of the brain seen in children. They are primarily cortical and gray matter abnormalities. Forty patients, divided into two groups, were studied. In one group were patients with the classic migrational lesions of lissencephaly, pachygyria, schizencephaly, heterotopia, and polymicrogyria in which the underlying cause is genetic, chromosomal, or unknown. In the second group were patients with lesions caused by a prenatally acquired infection (toxoplasmosis or cytomegalic virus) or a metabolic abnormality. The CT and MR imaging findings in these two groups are discussed

  20. New diffusion imaging method with a single acquisition sequence

    International Nuclear Information System (INIS)

    Melki, Ph.S.; Bittoun, J.; Lefevre, J.E.

    1987-01-01

    The apparent diffusion coefficient (ADC) is related to the molecular diffusion coefficient and to physiologic information: microcirculation in the capillary network, incoherent slow flow, and restricted diffusion. The authors present a new MR imaging sequence that yields computed ADC images in only one acquisition of 9-minutes with a 1.5-T imager (GE Signa). Compared to the previous method, this sequence is at least two times faster and thus can be used as a routine examination to supplement T1-, T2-, and density-weighted images. The method was assessed by measurement of the molecular diffusion in liquids, and the first clinical images obtained in neurologic diseases demonstrate its efficiency for clinical investigation. The possibility of separately imaging diffusion and perfusion is supported by an algorithm

  1. The role of high-resolution computed tomography (HRCT) and magnetic resonance imaging (MRI) in the diagnosis of preoperative and postoperative complications caused by acquired cholesteatomas

    International Nuclear Information System (INIS)

    Krestan, C.; Czerny, C.; Gstoettner, W.; Franz, P.

    2003-01-01

    The role of high-resolution computed tomography (HRCT) and magnetic resonance imaging (MRI) in the diagnosis of preoperative and postoperative complications caused by acquired cholesteatomas will be described in this paper. The pre- and postoperative imaging of the temporal bone was performed with HRCT and MRI. HRCT and MRI were performed in the axial and coronal plane. MRI was done with T2 weighted and T1 weighted sequences both before and after the intravenous application of contrast material. All imaging findings were confirmed clinically or surgically. The preoperative cholesteatoma-caused complications depicted by HRCT included bony erosions of the ossicles, scutum, facial canal in the middle ear, tympanic walls including the tegmen tympani, and of the labyrinth. The preoperative cholesteatoma-caused complications depicted by MRI included signs indicative for labyrinthitis, and brain abscess. Postoperative HRCT depicted bony erosions caused by recurrent cholesteatoma, bony defects of the facial nerve and of the labyrinth, and a defect of the tegmen tympani with a soft tissue mass in the middle ear. Postoperative MRI delineated neuritis of the facial nerve, labyrinthitis, and a meningo-encephalocele protruding into the middle ear. HRCT and MRI are excellent imaging tools to depict either bony or soft tissue complications or both if caused by acquired cholesteatomas. According to our findings and to the literature HRCT and MRI are complementary imaging methods to depict pre- or postoperative complications of acquired cholesteatomas if these are suspected by clinical examination. (orig.) [de

  2. Magnetic resonance imaging of acquired disorders of the pediatric female pelvis other than neoplasm

    International Nuclear Information System (INIS)

    Cox, Mougnyan; Gould, Sharon W.; Podberesky, Daniel J.; Epelman, Monica

    2016-01-01

    Transabdominal US remains the primary screening imaging modality of the pediatric female pelvis. However, MRI has become an invaluable adjunct to US in recent years. MRI offers superb soft-tissue contrast resolution that allows for detailed evaluation, particularly of the ovaries and their associated pathology. MRI can yield diagnostic information that is similar to or even better than that of US, especially in nonsexually active girls in whom transvaginal US would be contraindicated. MRI is generally a second-line examination and is preferred over CT because it does not involve the use of ionizing radiation. MRI might be underutilized in this population, particularly in differentiating surgical from nonsurgical conditions. This article reviews the relevant anatomy and discusses imaging of acquired conditions that involve the pediatric female genital tract, illustrating associated pathology with case examples. (orig.)

  3. Image processing for identification and quantification of filamentous bacteria in in situ acquired images.

    Science.gov (United States)

    Dias, Philipe A; Dunkel, Thiemo; Fajado, Diego A S; Gallegos, Erika de León; Denecke, Martin; Wiedemann, Philipp; Schneider, Fabio K; Suhr, Hajo

    2016-06-11

    In the activated sludge process, problems of filamentous bulking and foaming can occur due to overgrowth of certain filamentous bacteria. Nowadays, these microorganisms are typically monitored by means of light microscopy, commonly combined with staining techniques. As drawbacks, these methods are susceptible to human errors, subjectivity and limited by the use of discontinuous microscopy. The in situ microscope appears as a suitable tool for continuous monitoring of filamentous bacteria, providing real-time examination, automated analysis and eliminating sampling, preparation and transport of samples. In this context, a proper image processing algorithm is proposed for automated recognition and measurement of filamentous objects. This work introduces a method for real-time evaluation of images without any staining, phase-contrast or dilution techniques, differently from studies present in the literature. Moreover, we introduce an algorithm which estimates the total extended filament length based on geodesic distance calculation. For a period of twelve months, samples from an industrial activated sludge plant were weekly collected and imaged without any prior conditioning, replicating real environment conditions. Trends of filament growth rate-the most important parameter for decision making-are correctly identified. For reference images whose filaments were marked by specialists, the algorithm correctly recognized 72 % of the filaments pixels, with a false positive rate of at most 14 %. An average execution time of 0.7 s per image was achieved. Experiments have shown that the designed algorithm provided a suitable quantification of filaments when compared with human perception and standard methods. The algorithm's average execution time proved its suitability for being optimally mapped into a computational architecture to provide real-time monitoring.

  4. Assessing the consistency of UAV-derived point clouds and images acquired at different altitudes

    Science.gov (United States)

    Ozcan, O.

    2016-12-01

    Unmanned Aerial Vehicles (UAVs) offer several advantages in terms of cost and image resolution compared to terrestrial photogrammetry and satellite remote sensing system. Nowadays, UAVs that bridge the gap between the satellite scale and field scale applications were initiated to be used in various application areas to acquire hyperspatial and high temporal resolution imageries due to working capacity and acquiring in a short span of time with regard to conventional photogrammetry methods. UAVs have been used for various fields such as for the creation of 3-D earth models, production of high resolution orthophotos, network planning, field monitoring and agricultural lands as well. Thus, geometric accuracy of orthophotos and volumetric accuracy of point clouds are of capital importance for land surveying applications. Correspondingly, Structure from Motion (SfM) photogrammetry, which is frequently used in conjunction with UAV, recently appeared in environmental sciences as an impressive tool allowing for the creation of 3-D models from unstructured imagery. In this study, it was aimed to reveal the spatial accuracy of the images acquired from integrated digital camera and the volumetric accuracy of Digital Surface Models (DSMs) which were derived from UAV flight plans at different altitudes using SfM methodology. Low-altitude multispectral overlapping aerial photography was collected at the altitudes of 30 to 100 meters and georeferenced with RTK-GPS ground control points. These altitudes allow hyperspatial imagery with the resolutions of 1-5 cm depending upon the sensor being used. Preliminary results revealed that the vertical comparison of UAV-derived point clouds with respect to GPS measurements pointed out an average distance at cm-level. Larger values are found in areas where instantaneous changes in surface are present.

  5. Frequency-locked pulse sequencer for high-frame-rate monochromatic tissue motion imaging.

    Science.gov (United States)

    Azar, Reza Zahiri; Baghani, Ali; Salcudean, Septimiu E; Rohling, Robert

    2011-04-01

    To overcome the inherent low frame rate of conventional ultrasound, we have previously presented a system that can be implemented on conventional ultrasound scanners for high-frame-rate imaging of monochromatic tissue motion. The system employs a sector subdivision technique in the sequencer to increase the acquisition rate. To eliminate the delays introduced during data acquisition, a motion phase correction algorithm has also been introduced to create in-phase displacement images. Previous experimental results from tissue- mimicking phantoms showed that the system can achieve effective frame rates of up to a few kilohertz on conventional ultrasound systems. In this short communication, we present a new pulse sequencing strategy that facilitates high-frame-rate imaging of monochromatic motion such that the acquired echo signals are inherently in-phase. The sequencer uses the knowledge of the excitation frequency to synchronize the acquisition of the entire imaging plane to that of an external exciter. This sequencing approach eliminates any need for synchronization or phase correction and has applications in tissue elastography, which we demonstrate with tissue-mimicking phantoms. © 2011 IEEE

  6. Image sequence analysis workstation for multipoint motion analysis

    Science.gov (United States)

    Mostafavi, Hassan

    1990-08-01

    This paper describes an application-specific engineering workstation designed and developed to analyze motion of objects from video sequences. The system combines the software and hardware environment of a modem graphic-oriented workstation with the digital image acquisition, processing and display techniques. In addition to automation and Increase In throughput of data reduction tasks, the objective of the system Is to provide less invasive methods of measurement by offering the ability to track objects that are more complex than reflective markers. Grey level Image processing and spatial/temporal adaptation of the processing parameters is used for location and tracking of more complex features of objects under uncontrolled lighting and background conditions. The applications of such an automated and noninvasive measurement tool include analysis of the trajectory and attitude of rigid bodies such as human limbs, robots, aircraft in flight, etc. The system's key features are: 1) Acquisition and storage of Image sequences by digitizing and storing real-time video; 2) computer-controlled movie loop playback, freeze frame display, and digital Image enhancement; 3) multiple leading edge tracking in addition to object centroids at up to 60 fields per second from both live input video or a stored Image sequence; 4) model-based estimation and tracking of the six degrees of freedom of a rigid body: 5) field-of-view and spatial calibration: 6) Image sequence and measurement data base management; and 7) offline analysis software for trajectory plotting and statistical analysis.

  7. Quality study of portal images acquired by computed radiography and screen-film system under megavoltage ray

    International Nuclear Information System (INIS)

    Cao Guoquan; Jin Xiance; Wu Shixiu; Xie Congying; Zhang Li; Yu Jianyi; Li Yueqing

    2007-01-01

    Objective: To evaluate the quality of the portal images acquired by computed radiography (CR) system and conventional screen-film system, respectively. Methods: Imaging plates (IP) and X-ray films ora home-devised lead phantom with a leakage of 6.45% were acquired, and modulation transfer function (MTF) curves of the both images were measured using edge method. Portal images of 40 nasopharyngeal cancer patients were acquired by IP and screen-film system respectively. Two doctors with similar experience evaluated the damage degree of petrosal bone, the receiver operating characteristic (ROC) curve of CR images and general images were drawn according to two doctors evaluation results. Results: The identification frequency of CR system and screen-film system were 1.159 and 0.806 Lp/mm respectively. For doctor one, the area under ROC curve of CR images and general images were 0.802 and 0.742 respectively. For doctor two, the area under ROC curve of CR images and general images were 0.751 and 0.600 respectively. The MTF curve and ROC curve of CR are both better than those of screen-film system. Conclusion: The image quality of CR portal imaging is much better than that of screen-film system. The utility of CR in linear accelerator for portal imaging is promising in clinic. (authors)

  8. MR of normal pancreas : comparison of five pulse sequences and enhancing patterns on dynamic imaging

    International Nuclear Information System (INIS)

    Jang, Hyun Jung; Kim, Tae Kyoung; Hong, Sung Hwan; Han, Joon Koo; Choi, Byung Ihn

    1997-01-01

    To compare T1-weighted FLASH and turbo spin echo (SE) T2-weighted sequences with conventional T1- and T2-weighted sequences in imaging normal pancreas and to describe the enhancing patterns on dynamic MR imging. Forty-four patients with presumed hepatic hemangiomas were studied at 1.0T or 1.5T by using conventional SE sequences (T1-weighted, T2-weighted, and heavily T2-weighted), turbo-SE T2-weighted sequences, and breath-hold T1-weighted FLASH sequences acquired before, immediately on, and at 1, 2, 3, and 5 or 10 minutes after injection of a bolus of gadopentetate dimeglumine. No patients had either a history or its clinical features of pancreatic disease. Images were quantitatively analyzed for signal-difference-to noise ratios (SD/Ns) between the pancreas and peripancreatic fat. Percentage enhancement of the pancreas was measured on each dynamic MR image. Conspicuity of the pancreatic border was qualitatively evaluated according to a consensus, reached by three radiologists. Turbo-SE T2-weighted images had a significantly higher SD/N ratio (p<0.001) and better conspicuity of the pancreatic border (p<0.001) than SE T2- and heavily T2-weighted images;T1-weighted SE images had a significantly higher SD/N ratio than T1-weighted FLASH images (p<0.001), but there was no significant difference between tham in qualitative analysis (p=0.346). Percentage enhancement immediately on and at 1, 2, 3, 5, and 10 minutes after administration of contrast material was 39.9%, 44.5%, 42.9%, 40.8%, 36.3%, 29.9%, respectively, with peak enhancement at 1 minute. In MR imaging of normal pancreas, turbo-SE T2-weighted imaging is superior to SE T2- and heavily T2- weighted imaging, and SE T1-weighted imaging is superior to T1-weighted FLASH imaging. On serial gadolinium-enhanced FLASH imaging, normal pancreas shows peak enhancement at 1 minute

  9. MISTICA: Minimum Spanning Tree-Based Coarse Image Alignment for Microscopy Image Sequences.

    Science.gov (United States)

    Ray, Nilanjan; McArdle, Sara; Ley, Klaus; Acton, Scott T

    2016-11-01

    Registration of an in vivo microscopy image sequence is necessary in many significant studies, including studies of atherosclerosis in large arteries and the heart. Significant cardiac and respiratory motion of the living subject, occasional spells of focal plane changes, drift in the field of view, and long image sequences are the principal roadblocks. The first step in such a registration process is the removal of translational and rotational motion. Next, a deformable registration can be performed. The focus of our study here is to remove the translation and/or rigid body motion that we refer to here as coarse alignment. The existing techniques for coarse alignment are unable to accommodate long sequences often consisting of periods of poor quality images (as quantified by a suitable perceptual measure). Many existing methods require the user to select an anchor image to which other images are registered. We propose a novel method for coarse image sequence alignment based on minimum weighted spanning trees (MISTICA) that overcomes these difficulties. The principal idea behind MISTICA is to reorder the images in shorter sequences, to demote nonconforming or poor quality images in the registration process, and to mitigate the error propagation. The anchor image is selected automatically making MISTICA completely automated. MISTICA is computationally efficient. It has a single tuning parameter that determines graph width, which can also be eliminated by the way of additional computation. MISTICA outperforms existing alignment methods when applied to microscopy image sequences of mouse arteries.

  10. Geometrical primitives reconstruction from image sequence in an interactive context

    International Nuclear Information System (INIS)

    Monchal, L.; Aubry, P.

    1995-01-01

    We propose a method to recover 3D geometrical shape from image sequence, in a context of man machine co-operation. The human operator has to point out the edges of an object in the first image and choose a corresponding geometrical model. The algorithm tracks each relevant 2D segments describing surface discontinuities or limbs, in the images. Then, knowing motion of the camera between images, the positioning and the size of the virtual object are deduced by minimising a function. The function describes how well the virtual objects is linked to the extracted segments of the sequence, its geometrical model and pieces of information given by the operator. (author). 13 refs., 7 figs., 8 tabs

  11. MR imaging pulse sequence rationale: SD-, T1-, and T2-weighted images

    International Nuclear Information System (INIS)

    Sax, S.; Weathers, S.W.; Schneiders, N.J.; Horowitz, B.L.; Mawad, M.E.; Sandlin, M.E.; Blackwell, R.; Bryan, R.N.

    1986-01-01

    Over 500 patients have been examined with a pulse sequence designed to provide spin-density (SD)-weighted images (TR=3 sec, TE=35 msec), T1-weighted images (TR=0.3 sec, TE=35msec), and T2-weighted images (TR=3 sec, TE=105 msec) from which calculated ''synthesized'' images and SD, T1, and T2 calculated images could be obtained. Each image contributes unique information. SD-weighted images optimally display anatomy and often best highlight pathology. T1-weighted images are critical in assessing cerebral hemorrhages. T2-weighted images best display most lesions, but yield incomplete information in 35% of cases. All three types of ''weighted'' images are necessary to optimally display anatomy and fully characterize a lesion. Computerized calculations and simulations suggest that no other combination of pulse sequences yields equal information for a given examination time

  12. Non-negative factor analysis supporting the interpretation of elemental distribution images acquired by XRF

    International Nuclear Information System (INIS)

    Alfeld, Matthias; Falkenberg, Gerald; Wahabzada, Mirwaes; Bauckhage, Christian; Kersting, Kristian; Wellenreuther, Gerd

    2014-01-01

    Stacks of elemental distribution images acquired by XRF can be difficult to interpret, if they contain high degrees of redundancy and components differing in their quantitative but not qualitative elemental composition. Factor analysis, mainly in the form of Principal Component Analysis (PCA), has been used to reduce the level of redundancy and highlight correlations. PCA, however, does not yield physically meaningful representations as they often contain negative values. This limitation can be overcome, by employing factor analysis that is restricted to non-negativity. In this paper we present the first application of the Python Matrix Factorization Module (pymf) on XRF data. This is done in a case study on the painting Saul and David from the studio of Rembrandt van Rijn. We show how the discrimination between two different Co containing compounds with minimum user intervention and a priori knowledge is supported by Non-Negative Matrix Factorization (NMF).

  13. Research on hyperspectral dynamic scene and image sequence simulation

    Science.gov (United States)

    Sun, Dandan; Liu, Fang; Gao, Jiaobo; Sun, Kefeng; Hu, Yu; Li, Yu; Xie, Junhu; Zhang, Lei

    2016-10-01

    This paper presents a simulation method of hyperspectral dynamic scene and image sequence for hyperspectral equipment evaluation and target detection algorithm. Because of high spectral resolution, strong band continuity, anti-interference and other advantages, in recent years, hyperspectral imaging technology has been rapidly developed and is widely used in many areas such as optoelectronic target detection, military defense and remote sensing systems. Digital imaging simulation, as a crucial part of hardware in loop simulation, can be applied to testing and evaluation hyperspectral imaging equipment with lower development cost and shorter development period. Meanwhile, visual simulation can produce a lot of original image data under various conditions for hyperspectral image feature extraction and classification algorithm. Based on radiation physic model and material characteristic parameters this paper proposes a generation method of digital scene. By building multiple sensor models under different bands and different bandwidths, hyperspectral scenes in visible, MWIR, LWIR band, with spectral resolution 0.01μm, 0.05μm and 0.1μm have been simulated in this paper. The final dynamic scenes have high real-time and realistic, with frequency up to 100 HZ. By means of saving all the scene gray data in the same viewpoint image sequence is obtained. The analysis results show whether in the infrared band or the visible band, the grayscale variations of simulated hyperspectral images are consistent with the theoretical analysis results.

  14. Simulation and Efficient Measurements of Intensities for Complex Imaging Sequences

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Rasmussen, Morten Fischer; Stuart, Matthias Bo

    2014-01-01

    on the sequence to simulate both intensity and mechanical index (MI) according to FDA rules. A 3 MHz BK Medical 8820e convex array transducer is used with the SARUS scanner. An Onda HFL-0400 hydrophone and the Onda AIMS III system measures the pressure field for three imaging schemes: a fixed focus, single...

  15. Acquiring additional delayed PET images improves sensitivity and specificity in oncology cases

    International Nuclear Information System (INIS)

    Lamki, L.M.; Barron, B.J.; Mullani, N.; Joseph, U.; Ehert, E.

    2002-01-01

    Aim: This study looked into utility of acquiring PET images at 2-3 hours in addition to the standard whole body PET done at 1-hour after FDG injection in certain oncology cases. The objective is to evaluate whether the delayed additional images can decipher equivocal foci of FDG accumulation commonly seen in oncology patients. Typical example is the bowel activity that moves with time. Materials and Methods: PET protocol at our Institution in patients with colon Cancer, Pancreas Ca, Ovarian Ca and Breast Ca include a whole body PET (6-7 bed positions) done at 1-hour after 15 mCi F-18-FDG followed by select limited area PET scan (typically 2 bed stops over the area of interest) at 2-3 hours. Acquisition was undertaken on Siemens ECAT-EXACT Camera - 2-D acquisition and 8 mins. per bed position (5 mins. Emission and 3 mins. Transmission), 16.3 cm FOV and then Iterative Reconstruction. Results: Analysis of the first 115 patients who had additional delayed images resulted in 80% of patients where delayed images helped in interpretation. In 70% of these, delayed images helped in identifying physiological structures, e.g., ureters, bowel, blood vessels and muscles versus pathology. In 25%, they actually helped in identifying malignancy, e.g. more definite FDG accumulation. Almost all helped to boost the confidence of the reader. The contribution was mainly in differentiating bowel and ureter activity from cancer in the abdomen, as these change position with time. In case of pancreas and breast cancer, delayed images contributed in clarifying tumor metabolic activity as well. Inflammation and motion artifacts could also be better defined and so was muscle uptake. Conclusion: (1) Additional delayed PET imaging is very helpful in certain cancers in identifying more lesions and avoiding pitfalls. (2) They can yield higher sensitivity and specificity for colon, ovarian, breast and pancreas cancers. (3) Identification of physiologic structures and differentiation of these from

  16. Moving target detection based on temporal-spatial information fusion for infrared image sequences

    Science.gov (United States)

    Toing, Wu-qin; Xiong, Jin-yu; Zeng, An-jun; Wu, Xiao-ping; Xu, Hao-peng

    2009-07-01

    Moving target detection and localization is one of the most fundamental tasks in visual surveillance. In this paper, through analyzing the advantages and disadvantages of the traditional approaches about moving target detection, a novel approach based on temporal-spatial information fusion is proposed for moving target detection. The proposed method combines the spatial feature in single frame and the temporal properties within multiple frames of an image sequence of moving target. First, the method uses the spatial image segmentation for target separation from background and uses the local temporal variance for extracting targets and wiping off the trail artifact. Second, the logical "and" operator is used to fuse the temporal and spatial information. In the end, to the fusion image sequence, the morphological filtering and blob analysis are used to acquire exact moving target. The algorithm not only requires minimal computation and memory but also quickly adapts to the change of background and environment. Comparing with other methods, such as the KDE, the Mixture of K Gaussians, etc., the simulation results show the proposed method has better validity and higher adaptive for moving target detection, especially in infrared image sequences with complex illumination change, noise change, and so on.

  17. Optical flow estimation on image sequences with differently exposed frames

    Science.gov (United States)

    Bengtsson, Tomas; McKelvey, Tomas; Lindström, Konstantin

    2015-09-01

    Optical flow (OF) methods are used to estimate dense motion information between consecutive frames in image sequences. In addition to the specific OF estimation method itself, the quality of the input image sequence is of crucial importance to the quality of the resulting flow estimates. For instance, lack of texture in image frames caused by saturation of the camera sensor during exposure can significantly deteriorate the performance. An approach to avoid this negative effect is to use different camera settings when capturing the individual frames. We provide a framework for OF estimation on such sequences that contain differently exposed frames. Information from multiple frames are combined into a total cost functional such that the lack of an active data term for saturated image areas is avoided. Experimental results demonstrate that using alternate camera settings to capture the full dynamic range of an underlying scene can clearly improve the quality of flow estimates. When saturation of image data is significant, the proposed methods show superior performance in terms of lower endpoint errors of the flow vectors compared to a set of baseline methods. Furthermore, we provide some qualitative examples of how and when our method should be used.

  18. Studying a free fall experiment using short sequences of images

    International Nuclear Information System (INIS)

    Vera, Francisco; Romanque, Cristian

    2008-01-01

    We discuss a new alternative for obtaining position and time coordinates from a video of a free fall experiment. In our approach, after converting the video to a short sequence of images, the images are analyzed using a web page application developed by the author. The main advantage of the setup explained in this work, is that it is simple to use, no software license fees are necessary, and can be scaled-up to be used by a big number of students in introductory physics courses. The steps involved in the full analysis of a falling object are: we grab a short digital video of the experiment and convert it to a sequence of images, then, using a web page that includes all the necessary javascript, the student can easily click on the object of interest to obtain the (x,y,t) coordinates, finally, the student analyze motion using a spreadsheet.

  19. Effective spatial database support for acquiring spatial information from remote sensing images

    Science.gov (United States)

    Jin, Peiquan; Wan, Shouhong; Yue, Lihua

    2009-12-01

    In this paper, a new approach to maintain spatial information acquiring from remote-sensing images is presented, which is based on Object-Relational DBMS. According to this approach, the detected and recognized results of targets are stored and able to be further accessed in an ORDBMS-based spatial database system, and users can access the spatial information using the standard SQL interface. This approach is different from the traditional ArcSDE-based method, because the spatial information management module is totally integrated into the DBMS and becomes one of the core modules in the DBMS. We focus on three issues, namely the general framework for the ORDBMS-based spatial database system, the definitions of the add-in spatial data types and operators, and the process to develop a spatial Datablade on Informix. The results show that the ORDBMS-based spatial database support for image-based target detecting and recognition is easy and practical to be implemented.

  20. The imaging appearances of the pulmonary mucormycosis in patients with acquired immunodeficiency syndrome

    International Nuclear Information System (INIS)

    Liu Jinxin; Tang Xiaoping; Zhang Lieguang; Jiang Songfeng; Chen Bihua; Gan Xinqing; Huang Ruilian; Shi Hongling; Huang Wuzhi; Huang Deyang; Tang Yong

    2009-01-01

    Objective: To manifest the imaging appearances of the pulmonary mucormycosis in patients with acquired immunodeficiency syndrome (AIDS). Methods: The radiographic and high resolution computed tomography (HRCT) features of the pulmonary, mucormycosis in 13 patients with AIDS were retrospectively analyzed. Results: On radiography, the infiltrative lesions were found in 5 patients, 7 cases had reticular pattern, 4 cases had pleural effusion, 4 cases had enlarged hilar and mediastinal lymph nodes, 3 cases had diffuse milliary lesions, 3 cases had masses, 2 cases had ground-glass shadows, 2 cases had cystic lesions, cavity, pleural thickening, pericardial effusion and focal pneumothorax was presented in 1 case respectively. On HRCT, 7 cases had enlarged mediastinal lymph nodes, 7 cases had interlobular septal thickening, the infiltrative lesion were found in 6 patients, 5 cases had diffuse milliary lesions, 4 cases had pleural effusion, 3 cases had masses, 2 eases had ground-glass shadows, 2 cases had cystic lesions, cavity, pleural thickening, focal bronchiectasis, pericardial effusion and focal pneumothorax was presented in 1 case respectively. Conclusion: The main imaging appearances of the pulmonary mucormycosis in patients with AIDS include diffuse milliary lesion, enlarged hilar and mediastinal lymph node, interlobular septal thickening, infiltrative lesion, pleural effusion and mass. (authors)

  1. Extended -Regular Sequence for Automated Analysis of Microarray Images

    Directory of Open Access Journals (Sweden)

    Jin Hee-Jeong

    2006-01-01

    Full Text Available Microarray study enables us to obtain hundreds of thousands of expressions of genes or genotypes at once, and it is an indispensable technology for genome research. The first step is the analysis of scanned microarray images. This is the most important procedure for obtaining biologically reliable data. Currently most microarray image processing systems require burdensome manual block/spot indexing work. Since the amount of experimental data is increasing very quickly, automated microarray image analysis software becomes important. In this paper, we propose two automated methods for analyzing microarray images. First, we propose the extended -regular sequence to index blocks and spots, which enables a novel automatic gridding procedure. Second, we provide a methodology, hierarchical metagrid alignment, to allow reliable and efficient batch processing for a set of microarray images. Experimental results show that the proposed methods are more reliable and convenient than the commercial tools.

  2. Analysis of Magnetic Resonance Image Signal Fluctuations Acquired During MR-Guided Radiotherapy.

    Science.gov (United States)

    Breto, Adrian L; Padgett, Kyle R; Ford, John C; Kwon, Deukwoo; Chang, Channing; Fuss, Martin; Stoyanova, Radka; Mellon, Eric A

    2018-03-28

    Magnetic resonance-guided radiotherapy (MRgRT) is a new and evolving treatment modality that allows unprecedented visualization of the tumor and surrounding anatomy. MRgRT includes daily 3D magnetic resonance imaging (MRI) for setup and rapidly repeated near real-time MRI scans during treatment for target tracking. One of the more exciting potential benefits of MRgRT is the ability to analyze serial MRIs to monitor treatment response or predict outcomes. A typical radiation treatment (RT) over the span of 10-15 minutes on the MRIdian system (ViewRay, Cleveland, OH) yields thousands of "cine" images, each acquired in 250 ms. This unique data allows for a glimpse in image intensity changes during RT delivery. In this report, we analyze cine images from a single fraction RT of a glioblastoma patient on the ViewRay platform in order to characterize the dynamic signal changes occurring during RT therapy. The individual frames in the cines were saved into DICOM format and read into an MIM image analysis platform (MIM Software, Cleveland, OH) as a time series. The three possible states of the three Cobalt-60 radiation sources-OFF, READY, and ON-were also recorded. An in-house Java plugin for MIM was created in order to perform principal component analysis (PCA) on each of the datasets. The analysis resulted in first PC, related to monotonous signal increase over the course of the treatment fraction. We found several distortion patterns in the data that we postulate result from the perturbation of the magnetic field due to the moving metal parts in the platform while treatment was being administered. The largest variations were detected when all Cobalt-60 sources were OFF. During this phase of the treatment, the gantry and multi-leaf collimators (MLCs) are moving. Conversely, when all Cobalt-60 sources were in the ON position, the image signal fluctuations were minimal, relating to very little mechanical motion. At this phase, the gantry, the MLCs, and sources are fixed

  3. Acquired neuropathies.

    Science.gov (United States)

    Lozeron, Pierre; Trocello, Jean-Marc; Kubis, Nathalie

    2013-09-01

    Acquired neuropathies represent most of the neuropathies encountered in clinical practice. Hundreds of causes have been identified even though up to 41% of patients are still classified as idiopathic (Rajabally and Shah in J Neurol 258:1431-1436, 1). Routine evaluation relies on comprehensive medical history taking, clinical examination, nerve conduction studies and laboratory tests. Other investigations such as nerve biopsy or nerve or muscle imaging are performed in specific settings. This review focuses on recent advances in acquired neuropathies.

  4. Correlation of diagnostic imaging and autopsy findings of eight patients with acquired immune deficiency syndrome

    International Nuclear Information System (INIS)

    Li Hongjun; Zhang Yuzhong; Cheng Jingliang

    2009-01-01

    Objective: To investigate the imaging findings with pathologic correlation in patients with acquired immune deficiency syndrome (AIDS). Methods: Imaging findings, autopsy and pathological data were retrospectively analyzed in eight patients with AIDS. Routine CT scanning of different body parts was performed during their hospitalization. CT scanning was performed from the skull to the pelvis immediately following their death. After routine formalin fixing, 7 cadavers were cross sectioned for autopsy in freezing state and 1 for gross autopsy. Tissues were obtained from each sections and organs for pathological examinations. Results: The autopsy data showed parasitic infections (5 cases), bacterial infections (3 cases), fungal infections (2 cases), virus infections (2 cases), lymphoma (1 case) and cerebrovascular diseases (1 case)in eight patients with AIDS. The CT scanning demonstrated symmetrical ground glass liked shadows with pulmonary hilus as the center in 5 cases of pulmonary PCP infection; pulmonary patchy shadows, scattering distribution of nodular shadows, extensive military nodular shadows with even distribution and tuberculous pleurisy; cloudy shadows for 2 cases of fungi infection with multiple foci of chronic inflammation; pulmonary net-like parenchymal changes for 2 cases of pulmonary CMV infection; thickened intestinal wall and narrowed intestinal lumen for 1 case of intestinal tumor; low density shadows of brain tissue for 1 case of CMV encephalitis and MRI findings of high T 1 and high T 2 signals as well as MRA findings of broken vascular channels in liquefied areas of brain tissues; patchy low density areas inside a cyst of brain for one case of brain toxoplasmosis infection; multiple small patchy low density areas in cerebral basal ganglia for one case of brain cryptococcus infection. Conclusions: In AIDS patients, infection and tumor may occur in various organs resulting in complex symptoms, which makes it more complicated and difficult to make

  5. Image sequence analysis in nuclear medicine: (1) Parametric imaging using statistical modelling

    International Nuclear Information System (INIS)

    Liehn, J.C.; Hannequin, P.; Valeyre, J.

    1989-01-01

    This is a review of parametric imaging methods on Nuclear Medicine. A Parametric Image is an image in which each pixel value is a function of the value of the same pixel of an image sequence. The Local Model Method is the fitting of each pixel time activity curve by a model which parameter values form the Parametric Images. The Global Model Method is the modelling of the changes between two images. It is applied to image comparison. For both methods, the different models, the identification criterion, the optimization methods and the statistical properties of the images are discussed. The analysis of one or more Parametric Images is performed using 1D or 2D histograms. The statistically significant Parametric Images, (Images of significant Variances, Amplitudes and Differences) are also proposed [fr

  6. RECOGNITION OF DRAINAGE TUNNELS DURING GLACIER LAKE OUTBURST EVENTS FROM TERRESTRIAL IMAGE SEQUENCES

    Directory of Open Access Journals (Sweden)

    E. Schwalbe

    2016-06-01

    Full Text Available In recent years, many glaciers all over the world have been distinctly retreating and thinning. One of the consequences of this is the increase of so called glacier lake outburst flood events (GLOFs. The mechanisms ruling such GLOF events are still not yet fully understood by glaciologists. Thus, there is a demand for data and measurements that can help to understand and model the phenomena. Thereby, a main issue is to obtain information about the location and formation of subglacial channels through which some lakes, dammed by a glacier, start to drain. The paper will show how photogrammetric image sequence analysis can be used to collect such data. For the purpose of detecting a subglacial tunnel, a camera has been installed in a pilot study to observe the area of the Colonia Glacier (Northern Patagonian Ice Field where it dams the Lake Cachet II. To verify the hypothesis, that the course of the subglacial tunnel is indicated by irregular surface motion patterns during its collapse, the camera acquired image sequences of the glacier surface during several GLOF events. Applying tracking techniques to these image sequences, surface feature motion trajectories could be obtained for a dense raster of glacier points. Since only a single camera has been used for image sequence acquisition, depth information is required to scale the trajectories. Thus, for scaling and georeferencing of the measurements a GPS-supported photogrammetric network has been measured. The obtained motion fields of the Colonia Glacier deliver information about the glacier’s behaviour before during and after a GLOF event. If the daily vertical glacier motion of the glacier is integrated over a period of several days and projected into a satellite image, the location and shape of the drainage channel underneath the glacier becomes visible. The high temporal resolution of the motion fields may also allows for an analysis of the tunnels dynamic in comparison to the changing

  7. Exact fan-beam image reconstruction algorithm for truncated projection data acquired from an asymmetric half-size detector

    International Nuclear Information System (INIS)

    Leng Shuai; Zhuang Tingliang; Nett, Brian E; Chen Guanghong

    2005-01-01

    In this paper, we present a new algorithm designed for a specific data truncation problem in fan-beam CT. We consider a scanning configuration in which the fan-beam projection data are acquired from an asymmetrically positioned half-sized detector. Namely, the asymmetric detector only covers one half of the scanning field of view. Thus, the acquired fan-beam projection data are truncated at every view angle. If an explicit data rebinning process is not invoked, this data acquisition configuration will reek havoc on many known fan-beam image reconstruction schemes including the standard filtered backprojection (FBP) algorithm and the super-short-scan FBP reconstruction algorithms. However, we demonstrate that a recently developed fan-beam image reconstruction algorithm which reconstructs an image via filtering a backprojection image of differentiated projection data (FBPD) survives the above fan-beam data truncation problem. Namely, we may exactly reconstruct the whole image object using the truncated data acquired in a full scan mode (2π angular range). We may also exactly reconstruct a small region of interest (ROI) using the truncated projection data acquired in a short-scan mode (less than 2π angular range). The most important characteristic of the proposed reconstruction scheme is that an explicit data rebinning process is not introduced. Numerical simulations were conducted to validate the new reconstruction algorithm

  8. OBJECT-SPACE MULTI-IMAGE MATCHING OF MOBILE-MAPPING-SYSTEM IMAGE SEQUENCES

    Directory of Open Access Journals (Sweden)

    Y. C. Chen

    2012-07-01

    Full Text Available This paper proposes an object-space multi-image matching procedure of terrestrial MMS (Mobile Mapping System image sequences to determine the coordinates of an object point automatically and reliably. This image matching procedure can be applied to find conjugate points of MMS image sequences efficiently. Conventional area-based image matching methods are not reliable to deliver accurate matching results for this application due to image scale variations, viewing angle variations, and object occlusions. In order to deal with these three matching problems, an object space multi-image matching is proposed. A modified NCC (Normalized Cross Correlation coefficient is proposed to measure the similarity of image patches. A modified multi-window matching procedure will also be introduced to solve the problem of object occlusion. A coarse-to-fine procedure with a combination of object-space multi-image matching and multi-window matching is adopted. The proposed procedure has been implemented for the purpose of matching terrestrial MMS image sequences. The ratio of correct matches of this experiment was about 80 %. By providing an approximate conjugate point in an overlapping image manually, most of the incorrect matches could be fixed properly and the ratio of correct matches was improved up to 98 %.

  9. Imaging findings of disseminated pulmonary tuberculosis in patients with acquired immunodeficiency syndrome

    International Nuclear Information System (INIS)

    Song Wenyan; Zhao Zuqi; Zhao Dawei; Jia Cuiyu; Zhang Ruichi; Liu JinXin; Guan Wanhua; Liang Yi

    2013-01-01

    Objective: To study the imaging findings of disseminated pulmonary tuberculosis in patients with acquired immunodeficiency syndrome (AIDS). Methods: X-ray and multi-slice CT (MSCT) data from 33 AIDS patients with disseminated pulmonary tuberculosis confirmed by clinical manifestations and laboratory tests were analyzed retrospectively. Results: Thirty patients underwent initial chest radiography examination, 29 patients showed abnormal appearances, including bilateral disseminations in 21 patients and unilateral multiple disseminations in 8 patients. All patients underwent MSCT examination, 26 patients showed bilateral disseminations and 7 patients showed unilateral multiple disseminations. The abnormal pulmonary appearances included nodule (n = 25), miliary nodule (n = 22), air-space consolidation (n = 22), cavity (n = 11), fibrosis (n = 7), ground-glass opacity (n = 7), pneumatocele (n = 4), calcification (n = 2). There were 20 patients with more than 3 abnormal appearances and 13 patients with one or two abnormal appearances. The extra-pulmonary tuberculosis included pleural effusion (n = 33), lymphadenopathy (n = 30), intestinal tuberculosis (n = 3), splenic tuberculosis (n = 1) and cerebral tuberculosis (n = 1). Conclusion: Disseminated pulmonary tuberculosis should be highly suspected in AIDS patients with diffused nodules, miliary nodules, air-space consolidations or multiple cavities, accompanied with pleural effusion and lymphadenopathy. (authors)

  10. Imaging manifestations of acquired elastopathy resembling pseudoxanthoma elasticum in patients with beta thalassaemia major and sickle cell disease

    International Nuclear Information System (INIS)

    Narayana, Harish; Cheng, Ken; Lau, Ken; Harish, Radhika; Bowden, Donald K.

    2016-01-01

    Development of an acquired systemic elastopathy resembling pseudoxanthoma elasticum in patients with chronic haemoglobinopathies such as beta thalassaemia major and sickle cell disease is well documented. There is paucity of any comprehensive literature on the radiological manifestations of this entity. This pictorial review aims to describe and illustrate the multi system and multi modality imaging findings of this condition.

  11. Stigma models: Testing hypotheses of how images of Nevada are acquired and values are attached to them

    Energy Technology Data Exchange (ETDEWEB)

    Jenkins-Smith, H.C. [New Mexico Univ., Albuquerque, NM (United States)

    1994-12-01

    This report analyzes data from surveys on the effects that images associated with nuclear power and waste (i.e., nuclear images) have on people`s preference to vacation in Nevada. The analysis was stimulated by a model of imagery and stigma which assumes that information about a potentially hazardous facility generates signals that elicit negative images about the place in which it is located. Individuals give these images negative values (valences) that lessen their desire to vacation, relocate, or retire in that place. The model has been used to argue that the proposed Yucca Mountain high-level nuclear waste repository could elicit images of nuclear waste that would stigmatize Nevada and thus impose substantial economic losses there. This report proposes a revised model that assumes that the acquisition and valuation of images depend on individuals` ideological and cultural predispositions and that the ways in which new images will affect their preferences and behavior partly depend on these predispositions. The report tests these hypotheses: (1) individuals with distinct cultural and ideological predispositions have different propensities for acquiring nuclear images, (2) these people attach different valences to these images, (3) the variations in these valences are important, and (4) the valences of the different categories of images within an individual`s image sets for a place correlate very well. The analysis largely confirms these hypotheses, indicating that the stigma model should be revised to (1) consider the relevant ideological and cultural predispositions of the people who will potentially acquire and attach value to the image, (2) specify the kinds of images that previously attracted people to the host state, and (3) consider interactions between the old and potential new images of the place. 37 refs., 18 figs., 17 tabs.

  12. Acquiring and preprocessing leaf images for automated plant identification: understanding the tradeoff between effort and information gain

    Directory of Open Access Journals (Sweden)

    Michael Rzanny

    2017-11-01

    Full Text Available Abstract Background Automated species identification is a long term research subject. Contrary to flowers and fruits, leaves are available throughout most of the year. Offering margin and texture to characterize a species, they are the most studied organ for automated identification. Substantially matured machine learning techniques generate the need for more training data (aka leaf images. Researchers as well as enthusiasts miss guidance on how to acquire suitable training images in an efficient way. Methods In this paper, we systematically study nine image types and three preprocessing strategies. Image types vary in terms of in-situ image recording conditions: perspective, illumination, and background, while the preprocessing strategies compare non-preprocessed, cropped, and segmented images to each other. Per image type-preprocessing combination, we also quantify the manual effort required for their implementation. We extract image features using a convolutional neural network, classify species using the resulting feature vectors and discuss classification accuracy in relation to the required effort per combination. Results The most effective, non-destructive way to record herbaceous leaves is to take an image of the leaf’s top side. We yield the highest classification accuracy using destructive back light images, i.e., holding the plucked leaf against the sky for image acquisition. Cropping the image to the leaf’s boundary substantially improves accuracy, while precise segmentation yields similar accuracy at a substantially higher effort. The permanent use or disuse of a flash light has negligible effects. Imaging the typically stronger textured backside of a leaf does not result in higher accuracy, but notably increases the acquisition cost. Conclusions In conclusion, the way in which leaf images are acquired and preprocessed does have a substantial effect on the accuracy of the classifier trained on them. For the first time, this

  13. Stigma models: Testing hypotheses of how images of Nevada are acquired and values are attached to them

    International Nuclear Information System (INIS)

    Jenkins-Smith, H.C.

    1994-12-01

    This report analyzes data from surveys on the effects that images associated with nuclear power and waste (i.e., nuclear images) have on people's preference to vacation in Nevada. The analysis was stimulated by a model of imagery and stigma which assumes that information about a potentially hazardous facility generates signals that elicit negative images about the place in which it is located. Individuals give these images negative values (valences) that lessen their desire to vacation, relocate, or retire in that place. The model has been used to argue that the proposed Yucca Mountain high-level nuclear waste repository could elicit images of nuclear waste that would stigmatize Nevada and thus impose substantial economic losses there. This report proposes a revised model that assumes that the acquisition and valuation of images depend on individuals' ideological and cultural predispositions and that the ways in which new images will affect their preferences and behavior partly depend on these predispositions. The report tests these hypotheses: (1) individuals with distinct cultural and ideological predispositions have different propensities for acquiring nuclear images, (2) these people attach different valences to these images, (3) the variations in these valences are important, and (4) the valences of the different categories of images within an individual's image sets for a place correlate very well. The analysis largely confirms these hypotheses, indicating that the stigma model should be revised to (1) consider the relevant ideological and cultural predispositions of the people who will potentially acquire and attach value to the image, (2) specify the kinds of images that previously attracted people to the host state, and (3) consider interactions between the old and potential new images of the place. 37 refs., 18 figs., 17 tabs

  14. Accuracy Assessment of a Complex Building 3d Model Reconstructed from Images Acquired with a Low-Cost Uas

    Science.gov (United States)

    Oniga, E.; Chirilă, C.; Stătescu, F.

    2017-02-01

    Nowadays, Unmanned Aerial Systems (UASs) are a wide used technique for acquisition in order to create buildings 3D models, providing the acquisition of a high number of images at very high resolution or video sequences, in a very short time. Since low-cost UASs are preferred, the accuracy of a building 3D model created using this platforms must be evaluated. To achieve results, the dean's office building from the Faculty of "Hydrotechnical Engineering, Geodesy and Environmental Engineering" of Iasi, Romania, has been chosen, which is a complex shape building with the roof formed of two hyperbolic paraboloids. Seven points were placed on the ground around the building, three of them being used as GCPs, while the remaining four as Check points (CPs) for accuracy assessment. Additionally, the coordinates of 10 natural CPs representing the building characteristic points were measured with a Leica TCR 405 total station. The building 3D model was created as a point cloud which was automatically generated based on digital images acquired with the low-cost UASs, using the image matching algorithm and different software like 3DF Zephyr, Visual SfM, PhotoModeler Scanner and Drone2Map for ArcGIS. Except for the PhotoModeler Scanner software, the interior and exterior orientation parameters were determined simultaneously by solving a self-calibrating bundle adjustment. Based on the UAS point clouds, automatically generated by using the above mentioned software and GNSS data respectively, the parameters of the east side hyperbolic paraboloid were calculated using the least squares method and a statistical blunder detection. Then, in order to assess the accuracy of the building 3D model, several comparisons were made for the facades and the roof with reference data, considered with minimum errors: TLS mesh for the facades and GNSS mesh for the roof. Finally, the front facade of the building was created in 3D based on its characteristic points using the PhotoModeler Scanner

  15. Compression and Processing of Space Image Sequences of Northern Lights and Sprites

    DEFF Research Database (Denmark)

    Forchhammer, Søren Otto; Martins, Bo; Jensen, Ole Riis

    1999-01-01

    Compression of image sequences of auroral activity as northern lights and thunderstorms with sprites is investigated.......Compression of image sequences of auroral activity as northern lights and thunderstorms with sprites is investigated....

  16. Placental fetal stem segmentation in a sequence of histology images

    Science.gov (United States)

    Athavale, Prashant; Vese, Luminita A.

    2012-02-01

    Recent research in perinatal pathology argues that analyzing properties of the placenta may reveal important information on how certain diseases progress. One important property is the structure of the placental fetal stems. Analysis of the fetal stems in a placenta could be useful in the study and diagnosis of some diseases like autism. To study the fetal stem structure effectively, we need to automatically and accurately track fetal stems through a sequence of digitized hematoxylin and eosin (H&E) stained histology slides. There are many problems in successfully achieving this goal. A few of the problems are: large size of images, misalignment of the consecutive H&E slides, unpredictable inaccuracies of manual tracing, very complicated texture patterns of various tissue types without clear characteristics, just to name a few. In this paper we propose a novel algorithm to achieve automatic tracing of the fetal stem in a sequence of H&E images, based on an inaccurate manual segmentation of a fetal stem in one of the images. This algorithm combines global affine registration, local non-affine registration and a novel 'dynamic' version of the active contours model without edges. We first use global affine image registration of all the images based on displacement, scaling and rotation. This gives us approximate location of the corresponding fetal stem in the image that needs to be traced. We then use the affine registration algorithm "locally" near this location. At this point, we use a fast non-affine registration based on L2-similarity measure and diffusion regularization to get a better location of the fetal stem. Finally, we have to take into account inaccuracies in the initial tracing. This is achieved through a novel dynamic version of the active contours model without edges where the coefficients of the fitting terms are computed iteratively to ensure that we obtain a unique stem in the segmentation. The segmentation thus obtained can then be used as an

  17. Prostate contouring uncertainty in megavoltage computed tomography images acquired with a helical tomotherapy unit during image-guided radiation therapy

    International Nuclear Information System (INIS)

    Song, William Y.; Chiu, Bernard; Bauman, Glenn S.; Lock, Michael; Rodrigues, George; Ash, Robert; Lewis, Craig; Fenster, Aaron; Battista, Jerry J.; Van Dyk, Jake

    2006-01-01

    Purpose: To evaluate the image-guidance capabilities of megavoltage computed tomography (MVCT), this article compares the interobserver and intraobserver contouring uncertainty in kilovoltage computed tomography (KVCT) used for radiotherapy planning with MVCT acquired with helical tomotherapy. Methods and Materials: Five prostate-cancer patients were evaluated. Each patient underwent a KVCT and an MVCT study, a total of 10 CT studies. For interobserver variability analysis, four radiation oncologists, one physicist, and two radiation therapists (seven observers in total) contoured the prostate and seminal vesicles (SV) in the 10 studies. The intraobserver variability was assessed by asking all observers to repeat the contouring of 1 patient's KVCT and MVCT studies. Quantitative analysis of contour variations was performed by use of volumes and radial distances. Results: The interobserver and intraobserver contouring uncertainty was larger in MVCT compared with KVCT. Observers consistently segmented larger volumes on MVCT where the ratio of average prostate and SV volumes was 1.1 and 1.2, respectively. On average (interobserver and intraobserver), the local delineation variability, in terms of standard deviations [Δσ = √(σ 2 MVCT - σ 2 KVCT )], increased by 0.32 cm from KVCT to MVCT. Conclusions: Although MVCT was inferior to KVCT for prostate delineation, the application of MVCT in prostate radiotherapy remains useful

  18. Human genome sequencing with direct x-ray holographic imaging

    International Nuclear Information System (INIS)

    Rhodes, C.K.

    1993-01-01

    Direct holographic imaging of biological materials is widely applicable to the study of the structure, properties and action of genetic material. This particular application involves the sequencing of the human genome where prospective genomic imaging technology is composed of three subtechnologies, name an x-ray holographic camera, suitable chemistry and enzymology for the preparation of tagged DNA samples, and the illuminator in the form of an x-ray laser. We report appropriate x-ray camera, embodied by the instrument developed by MCR, is available and that suitable chemical and enzymatic procedures exist for the preparation of the necessary tagged DNA strands. Concerning the future development of the x-ray illuminator. We find that a practical small scale x-ray light source is indeed feasible. This outcome requires the use of unconventional physical processes in order to achieve the necessary power-compression in the amplifying medium. The understanding of these new physical mechanisms is developing rapidly. Importantly, although the x-ray source does not currently exist, the understanding of these new physical mechanisms is developing rapidly and the research has established the basic scaling laws that will determine the properties of the x-ray illuminator. When this x-ray source becomes available, an extremely rapid and cost effective instrument for 3-D imaging of biological materials can be applied to a wide range of biological structural assays, including the base-pair sequencing of the human genome and many questions regarding its higher levels of organization

  19. Superresolution restoration of an image sequence: adaptive filtering approach.

    Science.gov (United States)

    Elad, M; Feuer, A

    1999-01-01

    This paper presents a new method based on adaptive filtering theory for superresolution restoration of continuous image sequences. The proposed methodology suggests least squares (LS) estimators which adapt in time, based on adaptive filters, least mean squares (LMS) or recursive least squares (RLS). The adaptation enables the treatment of linear space and time-variant blurring and arbitrary motion, both of them assumed known. The proposed new approach is shown to be of relatively low computational requirements. Simulations demonstrating the superresolution restoration algorithms are presented.

  20. Safety Assessment of Advanced Imaging Sequences II: Simulations

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt

    2016-01-01

    .6%, when using the impulse response of the probe estimated from an independent measurement. The accuracy is increased to between -22% to 24.5% for MI and between -33.2% to 27.0% for Ispta.3, when using the pressure response measured at a single point to scale the simulation. The spatial distribution of MI...... Mechanical Index (MI) and Ispta.3 as required by FDA. The method is performed on four different imaging schemes and compared to measurements conducted using the SARUS experimental scanner. The sequences include focused emissions with an F-number of 2 with 64 elements that generate highly non-linear fields....... The simulation time is between 0.67 ms to 2.8 ms per emission and imaging point, making it possible to simulate even complex emission sequences in less than 1 s for a single spatial position. The linear simulations yield a relative accuracy on MI between -12.1% to 52.3% and for Ispta.3 between -38.6% to 62...

  1. Supervised detection of exoplanets in high-contrast imaging sequences

    Science.gov (United States)

    Gomez Gonzalez, C. A.; Absil, O.; Van Droogenbroeck, M.

    2018-06-01

    Context. Post-processing algorithms play a key role in pushing the detection limits of high-contrast imaging (HCI) instruments. State-of-the-art image processing approaches for HCI enable the production of science-ready images relying on unsupervised learning techniques, such as low-rank approximations, for generating a model point spread function (PSF) and subtracting the residual starlight and speckle noise. Aims: In order to maximize the detection rate of HCI instruments and survey campaigns, advanced algorithms with higher sensitivities to faint companions are needed, especially for the speckle-dominated innermost region of the images. Methods: We propose a reformulation of the exoplanet detection task (for ADI sequences) that builds on well-established machine learning techniques to take HCI post-processing from an unsupervised to a supervised learning context. In this new framework, we present algorithmic solutions using two different discriminative models: SODIRF (random forests) and SODINN (neural networks). We test these algorithms on real ADI datasets from VLT/NACO and VLT/SPHERE HCI instruments. We then assess their performances by injecting fake companions and using receiver operating characteristic analysis. This is done in comparison with state-of-the-art ADI algorithms, such as ADI principal component analysis (ADI-PCA). Results: This study shows the improved sensitivity versus specificity trade-off of the proposed supervised detection approach. At the diffraction limit, SODINN improves the true positive rate by a factor ranging from 2 to 10 (depending on the dataset and angular separation) with respect to ADI-PCA when working at the same false-positive level. Conclusions: The proposed supervised detection framework outperforms state-of-the-art techniques in the task of discriminating planet signal from speckles. In addition, it offers the possibility of re-processing existing HCI databases to maximize their scientific return and potentially improve

  2. Automated analysis of images acquired with electronic portal imaging device during delivery of quality assurance plans for inversely optimized arc therapy

    DEFF Research Database (Denmark)

    Fredh, Anna; Korreman, Stine; Rosenschöld, Per Munck af

    2010-01-01

    This work presents an automated method for comprehensively analyzing EPID images acquired for quality assurance of RapidArc treatment delivery. In-house-developed software has been used for the analysis and long-term results from measurements on three linacs are presented....

  3. Scan time reduction in {sup 23}Na-Magnetic Resonance Imaging using the chemical shift imaging sequence. Evaluation of an iterative reconstruction method

    Energy Technology Data Exchange (ETDEWEB)

    Weingaertner, Sebastian; Konstandin, Simon; Schad, Lothar R. [Heidelberg Univ., Mannheim (Germany). Computer Assisted Clinical Medicine; Wetterling, Friedrich [Heidelberg Univ., Mannheim (Germany). Computer Assisted Clinical Medicine; Dublin Univ. (Ireland) Trinity Inst. of Neuroscience; Fatar, Marc [Heidelberg Univ., Mannheim (Germany). Dept. of Neurology; Neumaier-Probst, Eva [Heidelberg Univ., Mannheim (Germany). Dept. of Neuroradiology

    2015-07-01

    To evaluate potential scan time reduction in {sup 23}Na-Magnetic Resonance Imaging with the chemical shift imaging sequence (CSI) using undersampled data of high-quality datasets, reconstructed with an iterative constrained reconstruction, compared to reduced resolution or reduced signal-to-noise ratio. CSI {sup 23}Na-images were retrospectively undersampled and reconstructed with a constrained reconstruction scheme. The results were compared to conventional methods of scan time reduction. The constrained reconstruction scheme used a phase constraint and a finite object support, which was extracted from a spatially registered {sup 1}H-image acquired with a double-tuned coil. The methods were evaluated using numerical simulations, phantom images and in-vivo images of a healthy volunteer and a patient who suffered from cerebral ischemic stroke. The constrained reconstruction scheme showed improved image quality compared to a decreased number of averages, images with decreased resolution or circular undersampling with weighted averaging for any undersampling factor. Brain images of a stroke patient, which were reconstructed from three-fold undersampled k-space data, resulted in only minor differences from the original image (normalized root means square error < 12%) and an almost identical delineation of the stroke region (mismatch < 6%). The acquisition of undersampled {sup 23}Na-CSI images enables up to three-fold scan time reduction with improved image quality compared to conventional methods of scan time saving.

  4. Wave Height Estimation from Shadowing Based on the Acquired X-Band Marine Radar Images in Coastal Area

    Directory of Open Access Journals (Sweden)

    Yanbo Wei

    2017-08-01

    Full Text Available In this paper, the retrieving significant wave height from X-band marine radar images based on shadow statistics is investigated, since the retrieving accuracy can not be seriously affected by environmental factors and the method has the advantage of without any external reference to calibrate. However, the accuracy of the significant wave height estimated from the radar image acquired at the near-shore area is not ideal. To solve this problem, the effect of water depth is considered in the theoretical derivation of estimated wave height based on the sea surface slope. And then, an improved retrieving algorithm which is suitable for both in deep water area and shallow water area is developed. In addition, the radar data are sparsely processed in advance in order to achieve high quality edge image for the requirement of shadow statistic algorithm, since the high resolution radar images will lead to angle-blurred for the image edge detection and time-consuming in the estimation of sea surface slope. The data acquired from Pingtan Test Base in Fujian Province were used to verify the effectiveness of the proposed algorithm. The experimental results demonstrate that the improved method which takes into account the water depth is more efficient and effective and has better performance for retrieving significant wave height in the shallow water area, compared to the in situ buoy data as the ground truth and that of the existing shadow statistic method.

  5. SU-E-J-216: A Sequence Independent Approach for Quantification of MR Image Deformations From Brachytherapy Applicators

    Energy Technology Data Exchange (ETDEWEB)

    Wieringen, N van; Heerden, L van; Gurney-Champion, O; Kesteren, Z van; Houweling, A; Pieters, B; Bel, A [Academic Medical Center, Amsterdam (Netherlands)

    2015-06-15

    Purpose: MRI is increasingly used as a single imaging modality for brachytherapy treatment planning. The presence of a brachytherapy applicator may cause distortions in the images, especially at higher field strengths. Our aim is to develop a procedure to quantify these distortions theoretically for any MR-sequence and to verify the estimated deformations for clinical sequences. Methods: Image distortions due to perturbation of the B0-field are proportional to the ratio of the induced frequency shift and the read-out bandwidth of the applied sequence. By reconstructing a frequency-shift map from the phase data from a multi-echo sequence, distortions can be calculated for any MR-sequence. Verification of this method for estimating distortions was performed by acquiring images with opposing read-out directions and consequently opposing distortions. The applicator shift can be determined by rigidly matching these images. Clinically, T2W-TSE-images are used for this purpose. For pre-clinical tests, EPI-sequences with narrow read-out bandwidth (19.5–47.5Hz), consequently large distortions, were added to the set of clinical MRsequences. To quantify deformations of the Utrecht Interstitial CT/MR applicator (Elekta Brachytherapy) on a Philips Ingenia 3T MRI, pre-clinical tests were performed in a phantom with the applicator in water, followed by clinical validation. Results: Deformations observed in the narrow bandwidth EPI-images were well predicted using the frequency-shift, the latter giving an overestimation up to 30%/up to 1 voxel. For clinically applied MR-sequences distortions were well below the voxel size. In patient setup distortions determined from the frequency-shift map were at sub-voxel level (<0.7mm). Using T2W-images larger distortions were found (1–2mm). This discrepancy was caused by patient movement between/during acquisition of the T2W-images with opposing read-out directions. Conclusion: Phantom experiments demonstrated the feasibility of a

  6. Allexiviruses may have acquired inserted sequences between the CP and CRP genes to change the translation reinitiation strategy of CRP.

    Science.gov (United States)

    Yoshida, Naoto; Shimura, Hanako; Masuta, Chikara

    2018-06-01

    Allexiviruses are economically important garlic viruses that are involved in garlic mosaic diseases. In this study, we characterized the allexivirus cysteine-rich protein (CRP) gene located just downstream of the coat protein (CP) gene in the viral genome. We determined the nucleotide sequences of the CP and CRP genes from numerous allexivirus isolates and performed a phylogenetic analysis. According to the resulting phylogenetic tree, we found that allexiviruses were clearly divided into two major groups (group I and group II) based on the sequences of the CP and CRP genes. In addition, the allexiviruses in group II had distinct sequences just before the CRP gene, while group I isolates did not. The inserted sequence between the CP and CRP genes was partially complementary to garlic 18S rRNA. Using a potato virus X vector, we showed that the CRPs affected viral accumulation and symptom induction in Nicotiana benthamiana, suggesting that the allexivirus CRP is a pathogenicity determinant. We assume that the inserted sequences before the CRP gene may have been generated during viral evolution to alter the termination-reinitiation mechanism for coupled translation of CP and CRP.

  7. Holistic and component plant phenotyping using temporal image sequence.

    Science.gov (United States)

    Das Choudhury, Sruti; Bashyam, Srinidhi; Qiu, Yumou; Samal, Ashok; Awada, Tala

    2018-01-01

    Image-based plant phenotyping facilitates the extraction of traits noninvasively by analyzing large number of plants in a relatively short period of time. It has the potential to compute advanced phenotypes by considering the whole plant as a single object (holistic phenotypes) or as individual components, i.e., leaves and the stem (component phenotypes), to investigate the biophysical characteristics of the plants. The emergence timing, total number of leaves present at any point of time and the growth of individual leaves during vegetative stage life cycle of the maize plants are significant phenotypic expressions that best contribute to assess the plant vigor. However, image-based automated solution to this novel problem is yet to be explored. A set of new holistic and component phenotypes are introduced in this paper. To compute the component phenotypes, it is essential to detect the individual leaves and the stem. Thus, the paper introduces a novel method to reliably detect the leaves and the stem of the maize plants by analyzing 2-dimensional visible light image sequences captured from the side using a graph based approach. The total number of leaves are counted and the length of each leaf is measured for all images in the sequence to monitor leaf growth. To evaluate the performance of the proposed algorithm, we introduce University of Nebraska-Lincoln Component Plant Phenotyping Dataset (UNL-CPPD) and provide ground truth to facilitate new algorithm development and uniform comparison. The temporal variation of the component phenotypes regulated by genotypes and environment (i.e., greenhouse) are experimentally demonstrated for the maize plants on UNL-CPPD. Statistical models are applied to analyze the greenhouse environment impact and demonstrate the genetic regulation of the temporal variation of the holistic phenotypes on the public dataset called Panicoid Phenomap-1. The central contribution of the paper is a novel computer vision based algorithm for

  8. Particle tracking from image sequences of complex plasma crystals

    International Nuclear Information System (INIS)

    Hadziavdic, Vedad; Melandsoe, Frank; Hanssen, Alfred

    2006-01-01

    In order to gather information about the physics of the complex plasma crystals from the experimental data, particles have to be tracked through a sequence of images. An application of the Kalman filter for that purpose is presented, using a one-dimensional approximation of the particle dynamics as a model for the filter. It is shown that Kalman filter is capable of tracking dust particles even with high levels of measurement noise. An inherent part of the Kalman filter, the innovation process, can be used to estimate values of the physical system parameters from the experimental data. The method is shown to be able to estimate the characteristic oscillation frequency from noisy data

  9. Imaging of cranial nerves with three-dimensional high resolution diffusion-weighted MR sequence based on SSFP technique

    International Nuclear Information System (INIS)

    Zhang Zhongwei; Chen Yingming; Meng Quanfei

    2008-01-01

    Objective: To depict the normal anatomy of cranial nerves in detail and define the exact relationships between cranial nerves and adjacent structures with three-dimensional high resolution diffusion-weighted MR sequence based on SSFP technique (3D DW-SSFP). Methods: 3D DW- SSFP sequence was performed and axial images were obtained in 12 healthy volunteers Post-processing techniques were used to generate images of cranial nerves, and the images acquired were compared with anatomical sections and diagrams of textbook. Results: In all subjects, 3D DW-SSFP sequence could produce homogeneous images and high contrast between the cranial nerves and other solid structures. The intracranial portions of all cranial nerves except olfactory nerve were identified; the extracranial portions of nerve Ⅱ-Ⅻ were identified in all subjects bilaterally. Conclusion: The 3D DW-SSFP sequence can characterize the normal MR appearance of cranial nerves and its branches and the ability to define the nerves may provide greater sensitivity and specificity in detecting abnormalities of craniofacial structure. (authors)

  10. Fast T1-weighted imaging using GRASE sequence for the female pelvis

    International Nuclear Information System (INIS)

    Dohke, Masako; Watanabe, Yuji; Kumashiro, Masayuki; Amoh, Yoshiki; Ishimori, Takayoshi; Oda, Kazushige; Okumura, Akira; Koike, Shinji; Dodo, Yoshihiro

    1998-01-01

    GRASE sequence, a combination of TSE and gradient echo, has been developed as a fast T 2 -weighted imaging technique. We have modified the GRASE sequence to be used for fast T 1 -weighted imaging of the female pelvis. In this article, we compared image quality and incidence of artifacts between T 1 -weighted GRASE images and conventional T 1 -weighted SE images. In a phantom study, signal-to-noise ratio was inferior in the GRASE images relative to corresponding on SE images. Susceptibility and chemical shift artifacts seen in GRASE images were seen with almost equal incidence in SE and TSE images. In a clinical study, we compared GRASE images with SE images in six patients with endometrial cysts and four patients with dermoid cysts. The overall image quality obtained with GRASE sequence was satisfactory in all patients and was almost identical with that obtained with SE sequence. GRASE images demonstrated endometrial cysts and dermoid cysts as clearly as did SE images. T 1 -weighted GRASE imaging, however, has a relatively long TE (35 ms) for T 1 -weighted images, which makes the signal intensity of urine and uterine endometrium with long T 2 values higher than in SE images. In conclusion, GRASE sequence can be used for fast T 1 -weighted imaging of the female pelvis because of short imaging time. (author)

  11. Study on excitation and fluorescence spectrums of Japanese citruses to construct machine vision systems for acquiring fluorescent images

    Science.gov (United States)

    Momin, Md. Abdul; Kondo, Naoshi; Kuramoto, Makoto; Ogawa, Yuichi; Shigi, Tomoo

    2011-06-01

    Research was conducted to acquire knowledge of the ultraviolet and visible spectrums from 300 -800 nm of some common varieties of Japanese citrus, to investigate the best wave-lengths for fluorescence excitation and the resulting fluorescence wave-lengths and to provide a scientific background for the best quality fluorescent imaging technique for detecting surface defects of citrus. A Hitachi U-4000 PC-based microprocessor controlled spectrophotometer was used to measure the absorption spectrum and a Hitachi F-4500 spectrophotometer was used for the fluorescence and excitation spectrums. We analyzed the spectrums and the selected varieties of citrus were categorized into four groups of known fluorescence level, namely strong, medium, weak and no fluorescence.The level of fluorescence of each variety was also examined by using machine vision system. We found that around 340-380 nm LEDs or UV lamps are appropriate as lighting devices for acquiring the best quality fluorescent image of the citrus varieties to examine their fluorescence intensity. Therefore an image acquisition device was constructed with three different lighting panels with UV LED at peak 365 nm, Blacklight blue lamps (BLB) peak at 350 nm and UV-B lamps at peak 306 nm. The results from fluorescent images also revealed that the findings of the measured spectrums worked properly and can be used for practical applications such as for detecting rotten, injured or damaged parts of a wide variety of citrus.

  12. Evaluation of full time and half time acquired cardiac perfusion images and its correlation with coronary angiography

    International Nuclear Information System (INIS)

    Madhusudhanan, P.; Kapoor, A.; Arya, A.; Ora, M.; Kheruka, S.; Dube, V.; Uttam Kumar; Verma, R.S.; Singh, R.D.; Gambhir, S.

    2010-01-01

    Full text: The myocardial perfusion study takes a longer time to complete. A reduction in acquisition time would mean reduced patient motion related artifacts, improvement in camera efficiency and reduction in cost. Iterative reconstruction algorithms produce more accurate images with fewer artifacts. Materials and Methods: Seventy three patients undergoing myocardial perfusion imaging were selected for additional half time acquisition. Patients with suspected or known coronary artery disease who have undergone coronary angiography recently were preferably included. Images were analysed in 4 groups - full time FBP, half time FBP, half time OSEM and half time OSEM. Three independent observers blinded to the clinical data and the acquisition protocol analysed images for change in image quality between these groups. Semiquantitative parameters of summed stress score, summed rest score, summed difference score and left ventricular ejection fraction were also compared using appropriate statistical methods. Results: No difference was noted in SSS, SRS, SDS and LVEF calculated for full time and half time. However, significant difference was found between SSS, SRS and SDS calculated for FBP and OSEM processed half time studies and no significant difference for LVEF calculated for these two groups. Significant change in image quality was noted by 2 observers only in 1.4% and 2.7% of cases. A true positivity rate of 88% was seen in comparison with coronary angiography. Conclusion: Gated myocardial perfusion SPECT images acquired in half the routine scan time provides equal diagnostic information compared to a conventional full time study, regardless of the processing protocol

  13. The Short Wave Aerostat-Mounted Imager (SWAMI): A novel platform for acquiring remotely sensed data from a tethered balloon

    Science.gov (United States)

    Vierling, L.A.; Fersdahl, M.; Chen, X.; Li, Z.; Zimmerman, P.

    2006-01-01

    We describe a new remote sensing system called the Short Wave Aerostat-Mounted Imager (SWAMI). The SWAMI is designed to acquire co-located video imagery and hyperspectral data to study basic remote sensing questions and to link landscape level trace gas fluxes with spatially and temporally appropriate spectral observations. The SWAMI can fly at altitudes up to 2 km above ground level to bridge the spatial gap between radiometric measurements collected near the surface and those acquired by other aircraft or satellites. The SWAMI platform consists of a dual channel hyperspectral spectroradiometer, video camera, GPS, thermal infrared sensor, and several meteorological and control sensors. All SWAMI functions (e.g. data acquisition and sensor pointing) can be controlled from the ground via wireless transmission. Sample data from the sampling platform are presented, along with several potential scientific applications of SWAMI data.

  14. Centrically reordered inversion recovery half-Fourier single-shot turbo spin-echo sequence: improvement of the image quality of oxygen-enhanced MRI

    International Nuclear Information System (INIS)

    Ohno, Yoshiharu; Hatabu, Hiroto; Higashino, Takanori; Kawamitsu, Hideaki; Watanabe, Hirokazu; Takenaka, Daisuke; Cauteren, Marc van; Sugimura, Kazuro

    2004-01-01

    Purpose: The purpose of the study presented here was to determine the improvement in image quality of oxygen-enhanced magnetic resonance (MR) subtraction imaging obtained with a centrically reordered inversion recovery half-Fourier single-shot turbo spin-echo (c-IR-HASTE) sequence compared with that obtained with a conventional sequentially reordered inversion recovery single-shot HASTE (s-IR-HASTE) sequence for pulmonary imaging. Materials and methods: Oxygen-enhanced MR imaging using a 1.5 T whole body scanner was performed on 12 healthy, non-smoking volunteers. Oxygen-enhanced MR images were obtained with the coronal two-dimensional (2D) c-IR-HASTE sequence and 2D s-IR-HASTE sequence combined with respiratory triggering. For a 256x256 matrix, 132 phase-encoding steps were acquired including four steps for phase correction. Inter-echo spacing for each sequence was 4.0 ms. The effective echo time (TE) for c-IR-HASTE was 4.0 ms, and 16 ms for s-IR-HASTE. The inversion time (TI) was 900 ms. To determine the improvement in oxygen-enhanced MR subtraction imaging by c-IR-HASTE, CNRs of subtraction image, overall image quality, and image degradation of the c-IR-HASTE and s-IR-HASTE techniques were statistically compared. Results: CNR, overall image quality, and image degradation of c-IR-HASTE images showed significant improvement compared to those s-IR-HASTE images (P<0.05). Conclusion: Centrically reordered inversion recovery half-Fourier single-shot turbo spin-echo (c-IR-HASTE) sequence enhanced the signal from the lung and improved the image quality of oxygen-enhanced MR subtraction imaging

  15. RADIOMETRIC NORMALIZATION OF LARGE AIRBORNE IMAGE DATA SETS ACQUIRED BY DIFFERENT SENSOR TYPES

    Directory of Open Access Journals (Sweden)

    S. Gehrke

    2016-06-01

    Full Text Available Generating seamless mosaics of aerial images is a particularly challenging task when the mosaic comprises a large number of im-ages, collected over longer periods of time and with different sensors under varying imaging conditions. Such large mosaics typically consist of very heterogeneous image data, both spatially (different terrain types and atmosphere and temporally (unstable atmo-spheric properties and even changes in land coverage. We present a new radiometric normalization or, respectively, radiometric aerial triangulation approach that takes advantage of our knowledge about each sensor’s properties. The current implementation supports medium and large format airborne imaging sensors of the Leica Geosystems family, namely the ADS line-scanner as well as DMC and RCD frame sensors. A hierarchical modelling – with parameters for the overall mosaic, the sensor type, different flight sessions, strips and individual images – allows for adaptation to each sensor’s geometric and radiometric properties. Additional parameters at different hierarchy levels can compensate radiome-tric differences of various origins to compensate for shortcomings of the preceding radiometric sensor calibration as well as BRDF and atmospheric corrections. The final, relative normalization is based on radiometric tie points in overlapping images, absolute radiometric control points and image statistics. It is computed in a global least squares adjustment for the entire mosaic by altering each image’s histogram using a location-dependent mathematical model. This model involves contrast and brightness corrections at radiometric fix points with bilinear interpolation for corrections in-between. The distribution of the radiometry fixes is adaptive to each image and generally increases with image size, hence enabling optimal local adaptation even for very long image strips as typi-cally captured by a line-scanner sensor. The normalization approach is implemented in

  16. MR imaging of the knee: Improvement of signal and contrast efficiency of T1-weighted turbo spin echo sequences by applying a driven equilibrium (DRIVE) pulse

    Energy Technology Data Exchange (ETDEWEB)

    Radlbauer, Rudolf, E-mail: rudolf.radlbauer@stpoelten.lknoe.a [MR Physics Group, Department of Radiology, Landesklinikum St. Poelten, Propst Fuehrer Strasse 4, 3100 St. Poelten (Austria); Lomoschitz, Friedrich, E-mail: friedrich.lomoschitz@stpoelten.lknoe.a [MR Physics Group, Department of Radiology, Landesklinikum St. Poelten, Propst Fuehrer Strasse 4, 3100 St. Poelten (Austria); Salomonowitz, Erich, E-mail: erich.salomonowitz@stpoelten.lknoe.a [MR Physics Group, Department of Radiology, Landesklinikum St. Poelten, Propst Fuehrer Strasse 4, 3100 St. Poelten (Austria); Eberhardt, Knut E., E-mail: info@mrt-kompetenzzentrum.d [MRT Competence Center Schloss Werneck, Balthasar-Neumann-Platz 2, 97440 Werneck (Germany); Stadlbauer, Andreas, E-mail: andi@nmr.a [MR Physics Group, Department of Radiology, Landesklinikum St. Poelten, Propst Fuehrer Strasse 4, 3100 St. Poelten (Austria); Department of Neurosurgery, University of Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen (Germany)

    2010-08-15

    The purpose of this study was to assess the effect of a driven equilibrium (DRIVE) pulse incorporated in a standard T1-weighted turbo spin echo (TSE) sequence as used in our routine MRI protocol for examination of pathologies of the knee. Sixteen consecutive patients with knee disorders were examined using the routine MRI protocol, including T1-weighted TSE-sequences with and without a DRIVE pulse. Signal-to-noise ratios (SNRs) and contrast-to-noise ratio (CNR) of anatomical structures and pathologies were calculated and compared for both sequences. The differences in diagnostic value of the T1-weighted images with and without DRIVE pulse were assessed. SNR was significantly higher on images acquired with DRIVE pulse for fluid, effusion, cartilage and bone. Differences in the SNR of meniscus and muscle between the two sequences were not statistically significant. CNR was significantly increased between muscle and effusion, fluid and cartilage, fluid and meniscus, cartilage and meniscus, bone and cartilage on images acquired using the DRIVE pulse. Diagnostic value of the T1-weighted images was found to be improved for delineation of anatomic structures and for diagnosing a variety of pathologies when a DRIVE pulse is incorporated in the sequence. Incorporation of a DRIVE pulse into a standard T1-weighted TSE-sequence leads to significant increase of SNR and CNR of both, anatomical structures and pathologies, and consequently to an increase in diagnostic value within the same acquisition time.

  17. MR imaging of the knee: Improvement of signal and contrast efficiency of T1-weighted turbo spin echo sequences by applying a driven equilibrium (DRIVE) pulse

    International Nuclear Information System (INIS)

    Radlbauer, Rudolf; Lomoschitz, Friedrich; Salomonowitz, Erich; Eberhardt, Knut E.; Stadlbauer, Andreas

    2010-01-01

    The purpose of this study was to assess the effect of a driven equilibrium (DRIVE) pulse incorporated in a standard T1-weighted turbo spin echo (TSE) sequence as used in our routine MRI protocol for examination of pathologies of the knee. Sixteen consecutive patients with knee disorders were examined using the routine MRI protocol, including T1-weighted TSE-sequences with and without a DRIVE pulse. Signal-to-noise ratios (SNRs) and contrast-to-noise ratio (CNR) of anatomical structures and pathologies were calculated and compared for both sequences. The differences in diagnostic value of the T1-weighted images with and without DRIVE pulse were assessed. SNR was significantly higher on images acquired with DRIVE pulse for fluid, effusion, cartilage and bone. Differences in the SNR of meniscus and muscle between the two sequences were not statistically significant. CNR was significantly increased between muscle and effusion, fluid and cartilage, fluid and meniscus, cartilage and meniscus, bone and cartilage on images acquired using the DRIVE pulse. Diagnostic value of the T1-weighted images was found to be improved for delineation of anatomic structures and for diagnosing a variety of pathologies when a DRIVE pulse is incorporated in the sequence. Incorporation of a DRIVE pulse into a standard T1-weighted TSE-sequence leads to significant increase of SNR and CNR of both, anatomical structures and pathologies, and consequently to an increase in diagnostic value within the same acquisition time.

  18. Abdominal MR imaging using a HASTE sequence : image comparison on the different echo times

    International Nuclear Information System (INIS)

    Park, Kwang Bo; Lee, Moon Gyu; Lim, Tae Hwan; Jeong, Yoong Ki; Ha, Hyun Kwon; Kim, Pyo Nyun; Auh, Yong Ho

    1999-01-01

    To determine the optimal parameters of abdominal HASTE imaging by means of a comparison of intermediate and long TE (echo time). We evaluated 30 consecutive patients who had undergone liver MR during a three-month period. Twelve patients were diagnosed as normal, four as having liver cirrhosis, and 14 were found to be suffering form hepatic hemangioma. On the basis of measured signal intensity of the liver, spleen, pancreas and gallbladder, and of fat, muscle, hemangioma, and background, we calculated the ratios of signal to noise (S/N), signal difference to noise (SD/N), and signal intensity (SI). Image quality was compared using these three ratios, and using two HASTE sequences with TEs of 90 msec and 134 msec, images were qualitatively evaluated. S/N ratio of the liver was higher when TE was 90 msec(p<.05), though S/N, SD/N and SI rations of the spleen, gallbladder, and pancreas-and of hemangiom-were higher when TE was 134 msec (p<.05). However, in muscle, all these three ratios were higher at a TE of 90 msec. SD/N ratio and SI of fat were higher at a TE of 134 msec. Overall image quality was better at a TE of 134 msec than at one of 90msec. A HASTE sequence with a TE of 134msec showed greater tissue contrast and stronger T2-weighted images than one with a TE of 90msec

  19. Magnetic resonance visualization of conductive structures by sequence-triggered direct currents and spin-echo phase imaging

    Energy Technology Data Exchange (ETDEWEB)

    Eibofner, Frank; Wojtczyk, Hanne; Graf, Hansjörg, E-mail: hansjoerg.graf@med.uni-tuebingen.de, E-mail: drGraf@t-online.de [Section on Experimental Radiology, University Hospital Tübingen, Tübingen D-72076 (Germany); Clasen, Stephan [Department of Diagnostic and Interventional Radiology, University Hospital Tübingen, Tübingen D-72076 (Germany)

    2014-06-15

    Purpose: Instrument visualization in interventional magnetic resonance imaging (MRI) is commonly performed via susceptibility artifacts. Unfortunately, this approach suffers from limited conspicuity in inhomogeneous tissue and disturbed spatial encoding. Also, susceptibility artifacts are controllable only by sequence parameters. This work presents the basics of a new visualization method overcoming such problems by applying sequence-triggered direct current (DC) pulses in spin-echo (SE) imaging. SE phase images allow for background free current path localization. Methods: Application of a sequence-triggered DC pulse in SE imaging, e.g., during a time period between radiofrequency excitation and refocusing, results in transient field inhomogeneities. Dependent on the additional z-magnetic field from the DC, a phase offset results despite the refocusing pulse. False spatial encoding is avoided by DC application during periods when read-out or slice-encoding gradients are inactive. A water phantom containing a brass conductor (water equivalent susceptibility) and a titanium needle (serving as susceptibility source) was used to demonstrate the feasibility. Artifact dependence on current strength and orientation was examined. Results: Without DC, the brass conductor was only visible due to its water displacement. The titanium needle showed typical susceptibility artifacts. Applying triggered DC pulses, the phase offset of spins near the conductor appeared. Because SE phase images are homogenous also in regions of persistent field inhomogeneities, the position of the conductor could be determined with high reliability. Artifact characteristic could be easily controlled by amperage leaving sequence parameters unchanged. For an angle of 30° between current and static field visualization was still possible. Conclusions: SE phase images display the position of a conductor carrying pulsed DC free from artifacts caused by persistent field inhomogeneities. Magnitude and phase

  20. Acquiring skill at medical image inspection: learning localized in early visual processes

    Science.gov (United States)

    Sowden, Paul T.; Davies, Ian R. L.; Roling, Penny; Watt, Simon J.

    1997-04-01

    Acquisition of the skill of medical image inspection could be due to changes in visual search processes, 'low-level' sensory learning, and higher level 'conceptual learning.' Here, we report two studies that investigate the extent to which learning in medical image inspection involves low- level learning. Early in the visual processing pathway cells are selective for direction of luminance contrast. We exploit this in the present studies by using transfer across direction of contrast as a 'marker' to indicate the level of processing at which learning occurs. In both studies twelve observers trained for four days at detecting features in x- ray images (experiment one equals discs in the Nijmegen phantom, experiment two equals micro-calcification clusters in digitized mammograms). Half the observers examined negative luminance contrast versions of the images and the remainder examined positive contrast versions. On the fifth day, observers swapped to inspect their respective opposite contrast images. In both experiments leaning occurred across sessions. In experiment one, learning did not transfer across direction of luminance contrast, while in experiment two there was only partial transfer. These findings are consistent with the contention that some of the leaning was localized early in the visual processing pathway. The implications of these results for current medical image inspection training schedules are discussed.

  1. Algorithms for detection of objects in image sequences captured from an airborne imaging system

    Science.gov (United States)

    Kasturi, Rangachar; Camps, Octavia; Tang, Yuan-Liang; Devadiga, Sadashiva; Gandhi, Tarak

    1995-01-01

    This research was initiated as a part of the effort at the NASA Ames Research Center to design a computer vision based system that can enhance the safety of navigation by aiding the pilots in detecting various obstacles on the runway during critical section of the flight such as a landing maneuver. The primary goal is the development of algorithms for detection of moving objects from a sequence of images obtained from an on-board video camera. Image regions corresponding to the independently moving objects are segmented from the background by applying constraint filtering on the optical flow computed from the initial few frames of the sequence. These detected regions are tracked over subsequent frames using a model based tracking algorithm. Position and velocity of the moving objects in the world coordinate is estimated using an extended Kalman filter. The algorithms are tested using the NASA line image sequence with six static trucks and a simulated moving truck and experimental results are described. Various limitations of the currently implemented version of the above algorithm are identified and possible solutions to build a practical working system are investigated.

  2. A Stochastic Approach for Blurred Image Restoration and Optical Flow Computation on Field Image Sequence

    Institute of Scientific and Technical Information of China (English)

    高文; 陈熙霖

    1997-01-01

    The blur in target images caused by camera vibration due to robot motion or hand shaking and by object(s) moving in the background scene is different to deal with in the computer vision system.In this paper,the authors study the relation model between motion and blur in the case of object motion existing in video image sequence,and work on a practical computation algorithm for both motion analysis and blut image restoration.Combining the general optical flow and stochastic process,the paper presents and approach by which the motion velocity can be calculated from blurred images.On the other hand,the blurred image can also be restored using the obtained motion information.For solving a problem with small motion limitation on the general optical flow computation,a multiresolution optical flow algoritm based on MAP estimation is proposed. For restoring the blurred image ,an iteration algorithm and the obtained motion velocity are used.The experiment shows that the proposed approach for both motion velocity computation and blurred image restoration works well.

  3. Fully automated rodent brain MR image processing pipeline on a Midas server: from acquired images to region-based statistics.

    Science.gov (United States)

    Budin, Francois; Hoogstoel, Marion; Reynolds, Patrick; Grauer, Michael; O'Leary-Moore, Shonagh K; Oguz, Ipek

    2013-01-01

    Magnetic resonance imaging (MRI) of rodent brains enables study of the development and the integrity of the brain under certain conditions (alcohol, drugs etc.). However, these images are difficult to analyze for biomedical researchers with limited image processing experience. In this paper we present an image processing pipeline running on a Midas server, a web-based data storage system. It is composed of the following steps: rigid registration, skull-stripping, average computation, average parcellation, parcellation propagation to individual subjects, and computation of region-based statistics on each image. The pipeline is easy to configure and requires very little image processing knowledge. We present results obtained by processing a data set using this pipeline and demonstrate how this pipeline can be used to find differences between populations.

  4. Quantitative comparison between a multiecho sequence and a single-echo sequence for susceptibility-weighted phase imaging.

    Science.gov (United States)

    Gilbert, Guillaume; Savard, Geneviève; Bard, Céline; Beaudoin, Gilles

    2012-06-01

    The aim of this study was to investigate the benefits arising from the use of a multiecho sequence for susceptibility-weighted phase imaging using a quantitative comparison with a standard single-echo acquisition. Four healthy adult volunteers were imaged on a clinical 3-T system using a protocol comprising two different three-dimensional susceptibility-weighted gradient-echo sequences: a standard single-echo sequence and a multiecho sequence. Both sequences were repeated twice in order to evaluate the local noise contribution by a subtraction of the two acquisitions. For the multiecho sequence, the phase information from each echo was independently unwrapped, and the background field contribution was removed using either homodyne filtering or the projection onto dipole fields method. The phase information from all echoes was then combined using a weighted linear regression. R2 maps were also calculated from the multiecho acquisitions. The noise standard deviation in the reconstructed phase images was evaluated for six manually segmented regions of interest (frontal white matter, posterior white matter, globus pallidus, putamen, caudate nucleus and lateral ventricle). The use of the multiecho sequence for susceptibility-weighted phase imaging led to a reduction of the noise standard deviation for all subjects and all regions of interest investigated in comparison to the reference single-echo acquisition. On average, the noise reduction ranged from 18.4% for the globus pallidus to 47.9% for the lateral ventricle. In addition, the amount of noise reduction was found to be strongly inversely correlated to the estimated R2 value (R=-0.92). In conclusion, the use of a multiecho sequence is an effective way to decrease the noise contribution in susceptibility-weighted phase images, while preserving both contrast and acquisition time. The proposed approach additionally permits the calculation of R2 maps. Copyright © 2012 Elsevier Inc. All rights reserved.

  5. An Algorithm for Pedestrian Detection in Multispectral Image Sequences

    Science.gov (United States)

    Kniaz, V. V.; Fedorenko, V. V.

    2017-05-01

    The growing interest for self-driving cars provides a demand for scene understanding and obstacle detection algorithms. One of the most challenging problems in this field is the problem of pedestrian detection. Main difficulties arise from a diverse appearances of pedestrians. Poor visibility conditions such as fog and low light conditions also significantly decrease the quality of pedestrian detection. This paper presents a new optical flow based algorithm BipedDetet that provides robust pedestrian detection on a single-borad computer. The algorithm is based on the idea of simplified Kalman filtering suitable for realization on modern single-board computers. To detect a pedestrian a synthetic optical flow of the scene without pedestrians is generated using slanted-plane model. The estimate of a real optical flow is generated using a multispectral image sequence. The difference of the synthetic optical flow and the real optical flow provides the optical flow induced by pedestrians. The final detection of pedestrians is done by the segmentation of the difference of optical flows. To evaluate the BipedDetect algorithm a multispectral dataset was collected using a mobile robot.

  6. Hounsfield unit recovery in clinical cone beam CT images of the thorax acquired for image guided radiation therapy

    DEFF Research Database (Denmark)

    Thing, Rune Slot; Bernchou, Uffe; Mainegra-Hing, Ernesto

    2016-01-01

    -correspondence with the planning CT images, and total volume HU error. Artefacts are reduced and CT-like HUs are recovered in the artefact corrected CBCT images. Visual inspection confirms that artefacts are indeed suppressed by the proposed method, and the HU root mean square difference between reconstructed CBCTs...

  7. Resolution and robustness to noise of the sensitivity-based method for microwave imaging with data acquired on cylindrical surfaces

    International Nuclear Information System (INIS)

    Zhang, Yifan; Tu, Sheng; Amineh, Reza K; Nikolova, Natalia K

    2012-01-01

    The spatial resolution limit of a Jacobian-based microwave imaging algorithm and its robustness to noise are evaluated. The focus here is on tomographic systems where the wideband data are acquired with a vertically scanned circular sensor array and at each scanning step a 2D image is reconstructed in the plane of the sensor array. The theoretical resolution is obtained as one-half of the maximum-frequency wavelength with far-zone data and about two-thirds of the array radius with near-zone data. Validation examples are given using analytical electromagnetic models. The algorithm is shown to be robust to noise when the response data are corrupted by Gaussian white noise. (paper)

  8. Acquiring a 2D rolled equivalent fingerprint image from a non-contact 3D finger scan

    Science.gov (United States)

    Fatehpuria, Abhishika; Lau, Daniel L.; Hassebrook, Laurence G.

    2006-04-01

    The use of fingerprints as a biometric is both the oldest mode of computer aided personal identification and the most relied-upon technology in use today. But current fingerprint scanning systems have some challenging and peculiar difficulties. Often skin conditions and imperfect acquisition circumstances cause the captured fingerprint image to be far from ideal. Also some of the acquisition techniques can be slow and cumbersome to use and may not provide the complete information required for reliable feature extraction and fingerprint matching. Most of the difficulties arise due to the contact of the fingerprint surface with the sensor platen. To attain a fast-capture, non-contact, fingerprint scanning technology, we are developing a scanning system that employs structured light illumination as a means for acquiring a 3-D scan of the finger with sufficiently high resolution to record ridge-level details. In this paper, we describe the postprocessing steps used for converting the acquired 3-D scan of the subject's finger into a 2-D rolled equivalent image.

  9. A framework for creating realistic synthetic fluorescence microscopy image sequences

    CSIR Research Space (South Africa)

    Mabaso, M

    2016-02-01

    Full Text Available Fluorescence microscopy imaging is an important tool in modern biological research, allowing insights into the processes of biological systems. Automated image analysis algorithms help in extracting information from these images. Validation...

  10. Fast Orientation of Video Images of Buildings Acquired from a UAV without Stabilization

    Science.gov (United States)

    Kedzierski, Michal; Delis, Paulina

    2016-01-01

    The aim of this research was to assess the possibility of conducting an absolute orientation procedure for video imagery, in which the external orientation for the first image was typical for aerial photogrammetry whereas the external orientation of the second was typical for terrestrial photogrammetry. Starting from the collinearity equations, assuming that the camera tilt angle is equal to 90°, a simplified mathematical model is proposed. The proposed method can be used to determine the X, Y, Z coordinates of points based on a set of collinearity equations of a pair of images. The use of simplified collinearity equations can considerably shorten the processing tine of image data from Unmanned Aerial Vehicles (UAVs), especially in low cost systems. The conducted experiments have shown that it is possible to carry out a complete photogrammetric project of an architectural structure using a camera tilted 85°–90° (φ or ω) and simplified collinearity equations. It is also concluded that there is a correlation between the speed of the UAV and the discrepancy between the established and actual camera tilt angles. PMID:27347954

  11. Fast Orientation of Video Images of Buildings Acquired from a UAV without Stabilization

    Directory of Open Access Journals (Sweden)

    Michal Kedzierski

    2016-06-01

    Full Text Available The aim of this research was to assess the possibility of conducting an absolute orientation procedure for video imagery, in which the external orientation for the first image was typical for aerial photogrammetry whereas the external orientation of the second was typical for terrestrial photogrammetry. Starting from the collinearity equations, assuming that the camera tilt angle is equal to 90°, a simplified mathematical model is proposed. The proposed method can be used to determine the X, Y, Z coordinates of points based on a set of collinearity equations of a pair of images. The use of simplified collinearity equations can considerably shorten the processing tine of image data from Unmanned Aerial Vehicles (UAVs, especially in low cost systems. The conducted experiments have shown that it is possible to carry out a complete photogrammetric project of an architectural structure using a camera tilted 85°–90° ( φ or ω and simplified collinearity equations. It is also concluded that there is a correlation between the speed of the UAV and the discrepancy between the established and actual camera tilt angles.

  12. Electronic spreadsheet to acquire the reflectance from the TM and ETM+ Landsat images

    Directory of Open Access Journals (Sweden)

    Antonio R. Formaggio

    2005-08-01

    Full Text Available The reflectance of agricultural cultures and other terrestrial surface "targets" is an intrinsic parameter of these targets, so in many situations, it must be used instead of the values of "gray levels" that is found in the satellite images. In order to get reflectance values, it is necessary to eliminate the atmospheric interference and to make a set of calculations that uses sensor parameters and information regarding the original image. The automation of this procedure has the advantage to speed up the process and to reduce the possibility of errors during calculations. The objective of this paper is to present an electronic spreadsheet that simplifies and automatizes the transformation of the digital numbers of the TM/Landsat-5 and ETM+/Landsat-7 images into reflectance. The method employed for atmospheric correction was the dark object subtraction (DOS. The electronic spreadsheet described here is freely available to users and can be downloaded at the following website: http://www.dsr.inpe.br/Calculo_Reflectancia.xls.

  13. Acquiring Multiview C-Arm Images to Assist Cardiac Ablation Procedures

    Directory of Open Access Journals (Sweden)

    Fallavollita Pascal

    2010-01-01

    Full Text Available CARTO XP is an electroanatomical cardiac mapping system that provides 3D color-coded maps of the electrical activity of the heart; however it is expensive and it can only use a single costly magnetic catheter for each patient intervention. Our approach consists of integrating fluoroscopic and electrical data from the RF catheters into the same image so as to better guide RF ablation, shorten the duration of this procedure, increase its efficacy, and decrease hospital cost when compared to CARTO XP. We propose a method that relies on multi-view C-arm fluoroscopy image acquisition for (1 the 3D reconstruction of the anatomical structure of interest, (2 the robust temporal tracking of the tip-electrode of a mapping catheter between the diastolic and systolic phases and (3 the 2D/3D registration of color coded isochronal maps directly on the 2D fluoroscopy image that would help the clinician guide the ablation procedure much more effectively. The method has been tested on canine experimental data.

  14. Synthesis of Multispectral Bands from Hyperspectral Data: Validation Based on Images Acquired by AVIRIS, Hyperion, ALI, and ETM+

    Science.gov (United States)

    Blonski, Slawomir; Glasser, Gerald; Russell, Jeffrey; Ryan, Robert; Terrie, Greg; Zanoni, Vicki

    2003-01-01

    Spectral band synthesis is a key step in the process of creating a simulated multispectral image from hyperspectral data. In this step, narrow hyperspectral bands are combined into broader multispectral bands. Such an approach has been used quite often, but to the best of our knowledge accuracy of the band synthesis simulations has not been evaluated thus far. Therefore, the main goal of this paper is to provide validation of the spectral band synthesis algorithm used in the ART software. The next section contains a description of the algorithm and an example of its application. Using spectral responses of AVIRIS, Hyperion, ALI, and ETM+, the following section shows how the synthesized spectral bands compare with actual bands, and it presents an evaluation of the simulation accuracy based on results of MODTRAN modeling. In the final sections of the paper, simulated images are compared with data acquired by actual satellite sensors. First, a Landsat 7 ETM+ image is simulated using an AVIRIS hyperspectral data cube. Then, two datasets collected with the Hyperion instrument from the EO-1 satellite are used to simulate multispectral images from the ALI and ETM+ sensors.

  15. Protocol optimization of sacroiliac joint MR Imaging at 3 Tesla: Impact of coil design and motion resistant sequences on image quality.

    Science.gov (United States)

    Gondim Teixeira, P A; Bravetti, M; Hossu, G; Lecocq, S; Petit, D; Loeuille, D; Blum, A

    2017-12-01

    To evaluate the impact of coil design and motion-resistant sequences on the quality of sacroiliac magnetic resonance imaging (MRI) examination in patients with spondyloarthropathy. One hundred and twenty-one patients with suspected sacroiliitis and referred for MRI of the sacroiliac joints were retrospectively evaluated with MRI at 3-Tesla. There were 78 women and 43 men with a mean age of 36.7±11.5 (SD) years (range: 15.8-78.4 years). Conventional and motion-resistant fat-saturated fast-spin echo T2-weighted sequences were performed with two different coils. Image quality was subjectively evaluated by two independent readers (R1 and R2) using a four-point scale. Confidence in the identification of bone marrow edema pattern (BMEP) was also evaluated subjectively using a three-point scale. Phased array body coil yielded improved image quality compared to surface coil (14.1 to 30.4% for R1 and 14.6 to 25.7% for R2; Pcoil with motion-resistant T2-weighted sequence (kappa 0.990). The smallest number of indeterminate BMEP zones was seen on MRI set acquired with the phased-array body coil and motion-resistant T2-weighted sequence. Phased array body coil and motion-resistant T2-weighted sequences perform better than surface coil and conventional T2-weighted sequences for the evaluation of sacroiliac joints, increasing confidence in the identification of BMEP. Copyright © 2017 Editions françaises de radiologie. Published by Elsevier Masson SAS. All rights reserved.

  16. SU-C-BRD-06: Sensitivity Study of An Automated System to Acquire and Analyze EPID Exit Dose Images

    Energy Technology Data Exchange (ETDEWEB)

    Olch, A; Zhuang, A [University of Southern California, Los Angeles, CA (United States)

    2015-06-15

    Purpose: The dosimetric consequences of errors in patient setup or beam delivery and anatomical changes are not readily known. A new product, PerFRACTION (Sun Nuclear Corporation), is designed to detect these errors by comparing the EPID exit dose image from each field of each fraction to those from baseline fraction images. This work investigates the sensitivity of PerFRACTION to detect the deviation of induced errors in a variety of realistic scenarios. Methods: Eight plans were created mimicking potential delivery or setup errors. The plans consisted of a nominal field and the field with an induced error. These were used to irradiate the EPID simulating multiple fractions with and without the error. Integrated EPID images were acquired in clinical mode and saved in ARIA. PerFRACTION automatically pulls the images into its database and performs the user defined comparison. In some cases, images were manually pushed to PerFRACTION. We varied the distance-to-agreement or dose tolerance until PerFRACTION showed failing pixels in the affected region and recorded the values. We induced errors of 1mm and greater in jaw, MLC, and couch position, 2 degree collimation rotation (patient yaw), and 0.5% to 1.5% in machine output. Both static and arc fields with the rails in or out were also acquired and compared. Results: PerFRACTION detected position errors of the jaws, MLC, and couch with an accuracy of better than 0.5 mm, and 0.2 degrees for collimator and gantry error. PerFRACTION detected a machine output error within 0.2% and detected the change in rail position. Conclusion: A new automated system for monitoring daily treatments for machine or patient variations from the first fraction using integrated EPID images was found to be sensitive enough to detect small positional, angular, and dosimetric errors within 0.5mm, 0.2 degrees, and 0.2%, respectively. Sun Nuclear Corporation has provided a software license for the product described.

  17. Compensation of inhomogeneous fluorescence signal distribution in 2D images acquired by confocal microscopy

    Czech Academy of Sciences Publication Activity Database

    Michálek, Jan; Čapek, Martin; Kubínová, Lucie

    2011-01-01

    Roč. 74, č. 9 (2011), s. 831-838 ISSN 1059-910X R&D Projects: GA ČR(CZ) GA102/08/0691; GA ČR(CZ) GA304/09/0733; GA MŠk(CZ) LC06063; GA MŠk(CZ) ME09010 Institutional research plan: CEZ:AV0Z50110509 Keywords : confocal laser scanning microscopy * image enhancement * morphology filters Subject RIV: JC - Computer Hardware ; Software Impact factor: 1.792, year: 2011

  18. Fast high-resolution MR imaging using the snapshot-FLASH MR sequence

    International Nuclear Information System (INIS)

    Matthaei, D.; Haase, A.; Henrich, D.; Duhmke, E.

    1990-01-01

    Snapshot, fast low-angle short (FLASH) MR imaging using an accelerated FLASH-MR sequence provides MR images with measuring times far below 1 second. The short TE of this sequence prevents susceptibility artifacts in gradient-echo imaging. In this paper variations of the sequence are shown that provide high resolution images with T1-weighted IR, T2-weighted SE, and chemical shift (CHESS) contrast sequences. METHODS AND MATERIALS: A whole-body 2-T system (Bruker-Medizintechnik) were used in combination with a 60-cm gradient system (providing gradient strength of 5 mT/m) to study healthy volunteers. The measuring time for a 256 x 256 image matrix was 800 msec. This sequence has been used in combination with T1-weighted IR, T2-weighted SE, and CHESS variations

  19. PET Imaging Stability Measurements During Simultaneous Pulsing of Aggressive MR Sequences on the SIGNA PET/MR System.

    Science.gov (United States)

    Deller, Timothy W; Khalighi, Mohammad Mehdi; Jansen, Floris P; Glover, Gary H

    2018-01-01

    The recent introduction of simultaneous whole-body PET/MR scanners has enabled new research taking advantage of the complementary information obtainable with PET and MRI. One such application is kinetic modeling, which requires high levels of PET quantitative stability. To accomplish the required PET stability levels, the PET subsystem must be sufficiently isolated from the effects of MR activity. Performance measurements have previously been published, demonstrating sufficient PET stability in the presence of MR pulsing for typical clinical use; however, PET stability during radiofrequency (RF)-intensive and gradient-intensive sequences has not previously been evaluated for a clinical whole-body scanner. In this work, PET stability of the GE SIGNA PET/MR was examined during simultaneous scanning of aggressive MR pulse sequences. Methods: PET performance tests were acquired with MR idle and during simultaneous MR pulsing. Recent system improvements mitigating RF interference and gain variation were used. A fast recovery fast spin echo MR sequence was selected for high RF power, and an echo planar imaging sequence was selected for its high heat-inducing gradients. Measurements were performed to determine PET stability under varying MR conditions using the following metrics: sensitivity, scatter fraction, contrast recovery, uniformity, count rate performance, and image quantitation. A final PET quantitative stability assessment for simultaneous PET scanning during functional MRI studies was performed with a spiral in-and-out gradient echo sequence. Results: Quantitation stability of a 68 Ge flood phantom was demonstrated within 0.34%. Normalized sensitivity was stable during simultaneous scanning within 0.3%. Scatter fraction measured with a 68 Ge line source in the scatter phantom was stable within the range of 40.4%-40.6%. Contrast recovery and uniformity were comparable for PET images acquired simultaneously with multiple MR conditions. Peak noise equivalent count

  20. Magnetic resonance imaging: early detection of central nervous system involvement in acquired immunodeficiency syndrome (AIDS)

    International Nuclear Information System (INIS)

    Trotot, P.M.; Sansonetti, P.J.; Levillain, R.; Cabanis, E.A.; Lavayssiere, R.; Sandoz-Tronca, C.

    1988-01-01

    Central Nervous System (CNS) involvement, whether primary by the Human Immunodeficiency Virus - HIV - itself, or secondary (toxoplasmosis or lymphoma) is remarkably frequent in AIDS, in 40 to 70% of cases, depending upon the author. In order to study the natural history of this illness, a cohort of 25 asymptomatic seropositive patients have been established. Every 6 months these patients undergo biological and clinical examinations, as well as Magnetic Resonance brain scans. After two examinations at a 6 month's interval, the first results are reported. Out of these 25 cases, 9 present anomalies: One patient with diffuse cerebral atrophy and 8 others with high signal intensity areas on T2 weighted sequences, like those of the Multiple Sclerosis. No relationship could be demonstrated between the existence of these lesions and various criteria such as age, sex, risk factors and T4 cells count. The nature of these lesions is not lear. They certainly indicate early involvement of the CNS after primary infection by the HIV virus. They may either represent scars of the primary infection or early alterations announcing developing encephalopathy [fr

  1. Diffusion tensor imaging of the auditory nerve in patients with acquired single-sided deafness

    DEFF Research Database (Denmark)

    Vos, Sjoerd; Haakma, Wieke; Versnel, Huib

    2015-01-01

    following cochlear hair cell loss, and the amount of degeneration may considerably differ between the two ears, also in patients with bilateral deafness. A measure that reflects the nerve's condition would help to assess the best of both nerves and decide accordingly which ear should be implanted......A cochlear implant (CI) can restore hearing in patients with profound sensorineural hearing loss by direct electrical stimulation of the auditory nerve. Therefore, the viability of the auditory nerve is vitally important in successful hearing recovery. However, the nerve typically degenerates...... single-sided sensorineural hearing loss. A specialized acquisition protocol was designed for a 3 T MRI scanner to image the small nerve bundle. The nerve was reconstructed using fiber tractography and DTI metrics - which reflect the nerve's microstructural properties - were computed per tract. Comparing...

  2. STrategically Acquired Gradient Echo (STAGE) imaging, part I: Creating enhanced T1 contrast and standardized susceptibility weighted imaging and quantitative susceptibility mapping.

    Science.gov (United States)

    Chen, Yongsheng; Liu, Saifeng; Wang, Yu; Kang, Yan; Haacke, E Mark

    2018-02-01

    To provide whole brain grey matter (GM) to white matter (WM) contrast enhanced T1W (T1WE) images, multi-echo quantitative susceptibility mapping (QSM), proton density (PD) weighted images, T1 maps, PD maps, susceptibility weighted imaging (SWI), and R2* maps with minimal misregistration in scanning times creating enhanced GM/WM contrast (the T1WE). The proposed T1WE image was created from a combination of the proton density weighted (6°, PDW) and T1W (24°) images and corrected for RF transmit field variations. Prior to the QSM calculation, a multi-echo phase unwrapping strategy was implemented using the unwrapped short echo to unwrap the longer echo to speed up computation. R2* maps were used to mask deep grey matter and veins during the iterative QSM calculation. A weighted-average sum of susceptibility maps was generated to increase the signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR). The proposed T1WE image has a significantly improved CNR both for WM to deep GM and WM to cortical GM compared to the acquired T1W image (the first echo of 24° scan) and the T1MPRAGE image. The weighted-average susceptibility maps have 80±26%, 55±22%, 108±33% SNR increases across the ten subjects compared to the single echo result of 17.5ms for the putamen, caudate nucleus, and globus pallidus, respectively. STAGE imaging offers the potential to create a standardized brain imaging protocol providing four pieces of quantitative tissue property information and multiple types of qualitative information in just 5min. Published by Elsevier Inc.

  3. Pulmonary cryptococcosis in rheumatoid arthritis (RA) patients: Comparison of imaging characteristics among RA, acquired immunodeficiency syndrome, and immunocompetent patients

    International Nuclear Information System (INIS)

    Yanagawa, Noriyo; Sakai, Fumikazu; Takemura, Tamiko; Ishikawa, Satoru; Takaki, Yasunobu; Hishima, Tsunekazu; Kamata, Noriko

    2013-01-01

    Purpose: The imaging characteristics of cryptococcosis in rheumatoid arthritis (RA) patients were analyzed by comparing them with those of acquired immunodeficiency syndrome (AIDS) and immunocompetent patients, and the imaging findings were correlated with pathological findings. Methods: Two radiologists retrospectively compared the computed tomographic (CT) findings of 35 episodes of pulmonary cryptococcosis in 31 patients with 3 kinds of underlying states (10 RA, 12 AIDS, 13 immunocompetent), focusing on the nature, number, and distribution of lesions. The pathological findings of 18 patients (8 RA, 2 AIDS, 8 immunocompetent) were analyzed by two pathologists, and then correlated with imaging findings. Results: The frequencies of consolidation and ground glass attenuation (GGA) were significantly higher, and the frequency of peripheral distribution was significantly lower in the RA group than in the immunocompetent group. Peripheral distribution was less common and generalized distribution was more frequent in the RA group than in the AIDS group. The pathological findings of the AIDS and immunocompetent groups reflected their immune status: There was lack of a granuloma reaction in the AIDS group, and a complete granuloma reaction in the immunocompetent group, while the findings of the RA group varied, including a complete granuloma reaction, a loose granuloma reaction and a hyper-immune reaction. Cases with the last two pathologic findings were symptomatic and showed generalized or central distribution on CT. Conclusion: Cryptococcosis in the RA group showed characteristic radiological and pathological findings compared with the other 2 groups

  4. Pulmonary cryptococcosis in rheumatoid arthritis (RA) patients: Comparison of imaging characteristics among RA, acquired immunodeficiency syndrome, and immunocompetent patients

    Energy Technology Data Exchange (ETDEWEB)

    Yanagawa, Noriyo, E-mail: noriyo_yana@ybb.ne.jp [Departments of Radiology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, 3-8-22, Honkomagome, Bunkyo-ku, Tokyo 113-8677 (Japan); Sakai, Fumikazu [Department of Diagnostic Radiology, Saitama Medical University International Medical Center, 1397-1 Yamane, Hidaka-shi, Saitama 350-1298 (Japan); Takemura, Tamiko [Department of Pathology, Japanese Red Cross Medical Center, 4-1-22 Hiroo, Shibuya-ku, Tokyo 150-8935 (Japan); Ishikawa, Satoru [Department of Respiratory Medicine, National Hospital Organization Chiba-East-Hospital, 673 Nitona-cho, Chuo-ku, Chiba-shi, Chiba 260-8712 (Japan); Takaki, Yasunobu [Departments of Radiology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, 3-8-22, Honkomagome, Bunkyo-ku, Tokyo 113-8677 (Japan); Hishima, Tsunekazu [Department of Pathology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, 3-8-22, Honkomagome, Bunkyo-ku, Tokyo 113-8677 (Japan); Kamata, Noriko [Departments of Radiology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, 3-8-22, Honkomagome, Bunkyo-ku, Tokyo 113-8677 (Japan)

    2013-11-01

    Purpose: The imaging characteristics of cryptococcosis in rheumatoid arthritis (RA) patients were analyzed by comparing them with those of acquired immunodeficiency syndrome (AIDS) and immunocompetent patients, and the imaging findings were correlated with pathological findings. Methods: Two radiologists retrospectively compared the computed tomographic (CT) findings of 35 episodes of pulmonary cryptococcosis in 31 patients with 3 kinds of underlying states (10 RA, 12 AIDS, 13 immunocompetent), focusing on the nature, number, and distribution of lesions. The pathological findings of 18 patients (8 RA, 2 AIDS, 8 immunocompetent) were analyzed by two pathologists, and then correlated with imaging findings. Results: The frequencies of consolidation and ground glass attenuation (GGA) were significantly higher, and the frequency of peripheral distribution was significantly lower in the RA group than in the immunocompetent group. Peripheral distribution was less common and generalized distribution was more frequent in the RA group than in the AIDS group. The pathological findings of the AIDS and immunocompetent groups reflected their immune status: There was lack of a granuloma reaction in the AIDS group, and a complete granuloma reaction in the immunocompetent group, while the findings of the RA group varied, including a complete granuloma reaction, a loose granuloma reaction and a hyper-immune reaction. Cases with the last two pathologic findings were symptomatic and showed generalized or central distribution on CT. Conclusion: Cryptococcosis in the RA group showed characteristic radiological and pathological findings compared with the other 2 groups.

  5. Short term reproducibility of a high contrast 3-D isotropic optic nerve imaging sequence in healthy controls

    Science.gov (United States)

    Harrigan, Robert L.; Smith, Alex K.; Mawn, Louise A.; Smith, Seth A.; Landman, Bennett A.

    2016-03-01

    The optic nerve (ON) plays a crucial role in human vision transporting all visual information from the retina to the brain for higher order processing. There are many diseases that affect the ON structure such as optic neuritis, anterior ischemic optic neuropathy and multiple sclerosis. Because the ON is the sole pathway for visual information from the retina to areas of higher level processing, measures of ON damage have been shown to correlate well with visual deficits. Increased intracranial pressure has been shown to correlate with the size of the cerebrospinal fluid (CSF) surrounding the ON. These measures are generally taken at an arbitrary point along the nerve and do not account for changes along the length of the ON. We propose a high contrast and high-resolution 3-D acquired isotropic imaging sequence optimized for ON imaging. We have acquired scan-rescan data using the optimized sequence and a current standard of care protocol for 10 subjects. We show that this sequence has superior contrast-to-noise ratio to the current standard of care while achieving a factor of 11 higher resolution. We apply a previously published automatic pipeline to segment the ON and CSF sheath and measure the size of each individually. We show that these measures of ON size have lower short- term reproducibility than the population variance and the variability along the length of the nerve. We find that the proposed imaging protocol is (1) useful in detecting population differences and local changes and (2) a promising tool for investigating biomarkers related to structural changes of the ON.

  6. A preliminary report of 99Tcm-ECD brain SPECT imaging in patients with acquired immunodeficiency syndrome

    International Nuclear Information System (INIS)

    Xu Hao; Tong Yuwei; Luo Jinxiang; Chen Jian; Wu Qiulian

    2001-01-01

    Objective: To investigate the changes of regional cerebral blood flow (rCBF) in patients with acquired immunodeficiency syndrome (AIDS). Methods: 99 Tc m -ECD brain SPECT imaging was performed on 5 patients with AIDS and 16 sex- and age-matched normal controls. The rCBF percentages compared to the cerebellum were calculated using a semi-quantitative processing software. Results: Hypo-perfusions in the right and left frontal, temporal, parietal lobe, basal ganglia and left thalamus were seen in 1 patient with dementia. Hypo-perfusions in the right and left frontal and temporal lobe were seen in 4 patients without dementia. The rCBF in the right and left frontal, temporal, parietal lobe, basal ganglia and thalamus, straight gyri and pons decreased significantly in patients with AIDS than those of the control subjects (P < 0.01). Conclusion: There is reduced cortico-subcortical rCBF in patients with AIDS

  7. 城市DSM的快速获取及其三维显示的研究%Fast Acquiring Urban DSM Image and Displaying 3D Image

    Institute of Scientific and Technical Information of China (English)

    尤红建; 刘彤; 苏林; 刘少创; 郭冠军; 李树楷

    2001-01-01

    城市数字表面模型(DSM)作为城市的重要信息有着十分广泛的应用,机载三维成像仪可以快速获取DSM数据,而无需地面控制点。该文介绍了利用三维成像仪快速获取城市DSM图像的数据处理技术,阐述了基于城市DSM影像显示城市三维模型的原理,着重分析了显示城市DSM图像奇异表面的方法和侧面处理思想。最后通过珠海、澳门地区飞行数据的处理和三维鸟瞰显示,说明了方法的可行性。%As an important urban information, urban digital surface models(DSM) are widely used in many fields. Airborne 3D imager which is developed by the Institute of Remote Sensing Applications, Chinese Academy of Sciences can acquire DSM in quasi-real-time without any ground control points. The data processing technology to acquire urban DSM by 3D imager is presented in this paper. How to display urban DSM which is different from natural surface in 3D is discussed in detail. An example of data processing and 3D displaying of urban DSM is given at the end. According to the fly test the efficiency of 3D imager is several times higher than that of traditional methods to acquire urban DSM, and the method to display urban DSM in 3D is feasible.

  8. Use of Variogram Parameters in Analysis of Hyperspectral Imaging Data Acquired from Dual-Stressed Crop Leaves

    Directory of Open Access Journals (Sweden)

    Christian Nansen

    2012-01-01

    Full Text Available A detailed introduction to variogram analysis of reflectance data is provided, and variogram parameters (nugget, sill, and range values were examined as possible indicators of abiotic (irrigation regime and biotic (spider mite infestation stressors. Reflectance data was acquired from 2 maize hybrids (Zea mays L. at multiple time points in 2 data sets (229 hyperspectral images, and data from 160 individual spectral bands in the spectrum from 405 to 907 nm were analyzed. Based on 480 analyses of variance (160 spectral bands × 3 variogram parameters, it was seen that most of the combinations of spectral bands and variogram parameters were unsuitable as stress indicators mainly because of significant difference between the 2 data sets. However, several combinations of spectral bands and variogram parameters (especially nugget values could be considered unique indicators of either abiotic or biotic stress. Furthermore, nugget values at 683 and 775 nm responded significantly to abiotic stress, and nugget values at 731 nm and range values at 715 nm responded significantly to biotic stress. Based on qualitative characterization of actual hyperspectral images, it was seen that even subtle changes in spatial patterns of reflectance values can elicit several-fold changes in variogram parameters despite non-significant changes in average and median reflectance values and in width of 95% confidence limits. Such scattered stress expression is in accordance with documented within-leaf variation in both mineral content and chlorophyll concentration and therefore supports the need for reflectance-based stress detection at a high spatial resolution (many hyperspectral reflectance profiles acquired from a single leaf and may be used to explain or characterize within-leaf foraging patterns of herbivorous arthropods.

  9. Imaging of acquired non-traumatic cochlear lesions: iconographic essay; Avaliacao por imagem das lesoes cocleares adquiridas (nao-traumaticas): ensaio iconografico

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Marcelo de Mattos; Gonzaga, Juliana Gontijo [Clinica Axial - Centro de Imagem, Belo Horizonte, MG (Brazil)]. E-mail: cidbh@cidbh.com.br; marcelogarcia@superig.com.br

    2006-04-15

    Different non-traumatic acquired cochlear lesions are shown in this article with imaging methods. They may be responsible for neuro sensorial hearing loss or vertigo. The method of choice is computed tomography when evaluating the osseous labyrinth whereas magnetic resonance imaging has superior resolution in the studies of the membranaceous labyrinth. (author)

  10. Mapping Reflectance Anisotropy of a Potato Canopy Using Aerial Images Acquired with an Unmanned Aerial Vehicle

    Directory of Open Access Journals (Sweden)

    Peter P. J. Roosjen

    2017-04-01

    Full Text Available Viewing and illumination geometry has a strong influence on optical measurements of natural surfaces due to their anisotropic reflectance properties. Typically, cameras on-board unmanned aerial vehicles (UAVs are affected by this because of their relatively large field of view (FOV and thus large range of viewing angles. In this study, we investigated the magnitude of reflectance anisotropy effects in the 500–900 nm range, captured by a frame camera mounted on a UAV during a standard mapping flight. After orthorectification and georeferencing of the images collected by the camera, we calculated the viewing geometry of all observations of each georeferenced ground pixel, forming a dataset with multi-angular observations. We performed UAV flights on two days during the summer of 2016 over an experimental potato field where different zones in the field received different nitrogen fertilization treatments. These fertilization levels caused variation in potato plant growth and thereby differences in structural properties such as leaf area index (LAI and canopy cover. We fitted the Rahman–Pinty–Verstraete (RPV model through the multi-angular observations of each ground pixel to quantify, interpret, and visualize the anisotropy patterns in our study area. The Θ parameter of the RPV model, which controls the proportion of forward and backward scattering, showed strong correlation with canopy cover, where in general an increase in canopy cover resulted in a reduction of backward scattering intensity, indicating that reflectance anisotropy contains information on canopy structure. In this paper, we demonstrated that anisotropy data can be extracted from measurements using a frame camera, collected during a typical UAV mapping flight. Future research will focus on how to use the anisotropy signal as a source of information for estimation of physical vegetation properties.

  11. An algorithm for longitudinal registration of PET/CT images acquired during neoadjuvant chemotherapy in breast cancer: preliminary results.

    Science.gov (United States)

    Li, Xia; Abramson, Richard G; Arlinghaus, Lori R; Chakravarthy, Anuradha Bapsi; Abramson, Vandana; Mayer, Ingrid; Farley, Jaime; Delbeke, Dominique; Yankeelov, Thomas E

    2012-11-16

    By providing estimates of tumor glucose metabolism, 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) can potentially characterize the response of breast tumors to treatment. To assess therapy response, serial measurements of FDG-PET parameters (derived from static and/or dynamic images) can be obtained at different time points during the course of treatment. However, most studies track the changes in average parameter values obtained from the whole tumor, thereby discarding all spatial information manifested in tumor heterogeneity. Here, we propose a method whereby serially acquired FDG-PET breast data sets can be spatially co-registered to enable the spatial comparison of parameter maps at the voxel level. The goal is to optimally register normal tissues while simultaneously preventing tumor distortion. In order to accomplish this, we constructed a PET support device to enable PET/CT imaging of the breasts of ten patients in the prone position and applied a mutual information-based rigid body registration followed by a non-rigid registration. The non-rigid registration algorithm extended the adaptive bases algorithm (ABA) by incorporating a tumor volume-preserving constraint, which computed the Jacobian determinant over the tumor regions as outlined on the PET/CT images, into the cost function. We tested this approach on ten breast cancer patients undergoing neoadjuvant chemotherapy. By both qualitative and quantitative evaluation, our constrained algorithm yielded significantly less tumor distortion than the unconstrained algorithm: considering the tumor volume determined from standard uptake value maps, the post-registration median tumor volume changes, and the 25th and 75th quantiles were 3.42% (0%, 13.39%) and 16.93% (9.21%, 49.93%) for the constrained and unconstrained algorithms, respectively (p = 0.002), while the bending energy (a measure of the smoothness of the deformation) was 0.0015 (0.0005, 0.012) and 0.017 (0.005, 0

  12. Measurement of capillary lenght from 3D images acquired by confocal microscopy using image analysis and stereology

    Czech Academy of Sciences Publication Activity Database

    Kubínová, Lucie; Janáček, Jiří; Eržen, I.; Mao, X. W.

    2010-01-01

    Roč. 16, Suppl.2 (2010), s. 736-737 ISSN 1431-9276. [Microscopy and Microanalysis 2010. Portland, 01.08.2010-05.08.2010] R&D Projects: GA MŠk(CZ) LC06063; GA MŠk(CZ) ME09010; GA MŠk(CZ) MEB090910; GA ČR(CZ) GA304/09/0733 Institutional research plan: CEZ:AV0Z50110509 Keywords : capillary length * confocal microscopy * image analysis Subject RIV: EA - Cell Biology Impact factor: 2.179, year: 2010

  13. Real-time UAV trajectory generation using feature points matching between video image sequences

    Science.gov (United States)

    Byun, Younggi; Song, Jeongheon; Han, Dongyeob

    2017-09-01

    Unmanned aerial vehicles (UAVs), equipped with navigation systems and video capability, are currently being deployed for intelligence, reconnaissance and surveillance mission. In this paper, we present a systematic approach for the generation of UAV trajectory using a video image matching system based on SURF (Speeded up Robust Feature) and Preemptive RANSAC (Random Sample Consensus). Video image matching to find matching points is one of the most important steps for the accurate generation of UAV trajectory (sequence of poses in 3D space). We used the SURF algorithm to find the matching points between video image sequences, and removed mismatching by using the Preemptive RANSAC which divides all matching points to outliers and inliers. The inliers are only used to determine the epipolar geometry for estimating the relative pose (rotation and translation) between image sequences. Experimental results from simulated video image sequences showed that our approach has a good potential to be applied to the automatic geo-localization of the UAVs system

  14. MR imaging of the temporomandibular joint. Part 2. Effect of flip angle on MR imaging with FLASH sequence

    International Nuclear Information System (INIS)

    Sakamoto, Maya; Sasano, Takashi; Higano, Shuichi; Takahashi, Shoki; Kurihara, Noriko

    1998-01-01

    In our previous study on MR imaging of the temporomandibular joint (TMJ), fast low angle shot (FLASH) showed the highest image contrast between disc and surrounding TMJ tissues compared with those of 4 other sequences (i,e., fast imaging with steady precession (FISP), conventional T1-weighted spin echo (SE) and fast spin echo (FSE, TR/TE/ETL: 1100/12/3, 3000/15/7)). Furthermore, FLASH also received a high score on visual evaluation including the position and contour of the disc, and the border between the disc and surrounding tissues. Therefore, we concluded that FLASH was the most suitable sequence for evaluating the TMJ disc. However, the image contrast and signal intensity on MR imaging with gradient echo pulse sequence are affected by flip angle. Consequently, in this report, to find the most suitable flip angle for MR scanning of the TMJ using a FLASH sequence (TR/TE: 450/11), ten TMJs of 5 volunteers were experimentally imaged with various flip angles from 10 degrees to 70 degrees at an interval of 10 degrees between 10 to 70. The image contrast and contrast-to-noise ratio (CNR) between the disc and surrounding tissues were compared. In addition, signal-to-noise ratio (SNR) of phantoms was also calculated using the same imaging parameters. Visual evaluation including position and contour of the disc, and the border between the disc and surrounding tissues, was also performed by 4 radiologists. As the flip angle increased, imaging contrast decreased while SNR increased. Images with flip angles between 30 and 60 degrees demonstrated high CNR. On visual evaluation, images using flip angles between 30 and 50 degrees received high scores. In conclusion, FLASH sequence with a flip angle between 30 and 50 degrees was considered most suitable for evaluating the TMJ disc based on the results of visual assessment and analysis of three major components of image diagnostic quality: image contrast, CNR and SNR. (author)

  15. MR imaging of articular cartilage in the ankle: comparison of available imaging sequences and methods of measurement in cadavers

    Energy Technology Data Exchange (ETDEWEB)

    Tan, T.C.F. [Department of Radiology, Veterans Administrative Medical Center, San Diego, CA (United States)]|[University of California Medical Center, San Diego, CA (United States)]|[Department of Radiology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan (Taiwan, Province of China); Wilcox, D.M. [Department of Radiology, Veterans Administrative Medical Center, San Diego, CA (United States)]|[University of California Medical Center, San Diego, CA (United States); Frank, L. [Department of Radiology, Veterans Administrative Medical Center, San Diego, CA (United States)]|[University of California Medical Center, San Diego, CA (United States); Shih, C. [Department of Radiology, Veterans Administrative Medical Center, San Diego, CA (United States)]|[University of California Medical Center, San Diego, CA (United States)]|[Department of Radiology, Veterans General Hospital-Taipei (Taiwan, Province of China); Trudell, D.J. [Department of Radiology, Veterans Administrative Medical Center, San Diego, CA (United States)]|[University of California Medical Center, San Diego, CA (United States); Sartoris, D.J. [Department of Radiology, Veterans Administrative Medical Center, San Diego, CA (United States)]|[University of California Medical Center, San Diego, CA (United States); Resnick, D. [Department of Radiology, Veterans Administrative Medical Center, San Diego, CA (United States)]|[University of California Medical Center, San Diego, CA (United States)

    1996-11-01

    Objective. To assess hyaline cartilage of cadaveric ankles using different magnetic resonance (MR) imaging techniques and various methods of measurement. Design and patients. Cartilage thicknesses of the talus and tibia were measured in ten cadaveric ankles by naked eye and by digitized image analysis from MR images of fat-suppressed T1-weighted gradient recalled (FS-SPGR), sequences and pulsed transfer saturation sequences with (FS-STS) and without fat-suppression (STS); these measurements were compared with those derived from direct inspection of cadaveric sections. The accuracy and precision errors were evaluated statistically for each imaging technique as well as measuring method. Contrast-to-noise ratios of cartilage versus joint fluid and marrow were compared for each of the imaging sequences. Results. Statistically, measurements from FS-SPGR images were associated with the smallest estimation error. Precision error of measurements derived from digitized image analysis was found to be smaller than that derived from naked eye measurements. Cartilage thickness measurements in images from STS and FS-STS sequences revealed larger errors in both accuracy and precision. Interobserver variance was larger in naked eye assessment of the cartilage. Contrast-to-noise ratio of cartilage versus joint fluid and marrow was higher with FS-SPGR than with FS-STS or STS sequences. Conclusion. Of the sequences and measurement techniques studied, the FS-SPGR sequence combined with the use of digitized image analysis provides the most accurate method for the assessment of ankle hyaline cartilage. (orig.). With 3 figs., 2 tabs.

  16. MR imaging of articular cartilage in the ankle: comparison of available imaging sequences and methods of measurement in cadavers

    International Nuclear Information System (INIS)

    Tan, T.C.F.; Wilcox, D.M.; Frank, L.; Shih, C.; Trudell, D.J.; Sartoris, D.J.; Resnick, D.

    1996-01-01

    Objective. To assess hyaline cartilage of cadaveric ankles using different magnetic resonance (MR) imaging techniques and various methods of measurement. Design and patients. Cartilage thicknesses of the talus and tibia were measured in ten cadaveric ankles by naked eye and by digitized image analysis from MR images of fat-suppressed T1-weighted gradient recalled (FS-SPGR), sequences and pulsed transfer saturation sequences with (FS-STS) and without fat-suppression (STS); these measurements were compared with those derived from direct inspection of cadaveric sections. The accuracy and precision errors were evaluated statistically for each imaging technique as well as measuring method. Contrast-to-noise ratios of cartilage versus joint fluid and marrow were compared for each of the imaging sequences. Results. Statistically, measurements from FS-SPGR images were associated with the smallest estimation error. Precision error of measurements derived from digitized image analysis was found to be smaller than that derived from naked eye measurements. Cartilage thickness measurements in images from STS and FS-STS sequences revealed larger errors in both accuracy and precision. Interobserver variance was larger in naked eye assessment of the cartilage. Contrast-to-noise ratio of cartilage versus joint fluid and marrow was higher with FS-SPGR than with FS-STS or STS sequences. Conclusion. Of the sequences and measurement techniques studied, the FS-SPGR sequence combined with the use of digitized image analysis provides the most accurate method for the assessment of ankle hyaline cartilage. (orig.). With 3 figs., 2 tabs

  17. INTEGRATION OF POINT CLOUDS AND IMAGES ACQUIRED FROM A LOW-COST NIR CAMERA SENSOR FOR CULTURAL HERITAGE PURPOSES

    Directory of Open Access Journals (Sweden)

    M. Kedzierski

    2017-08-01

    Full Text Available Terrestrial Laser Scanning is currently one of the most common techniques for modelling and documenting structures of cultural heritage. However, only geometric information on its own, without the addition of imagery data is insufficient when formulating a precise statement about the status of studies structure, for feature extraction or indicating the sites to be restored. Therefore, the Authors propose the integration of spatial data from terrestrial laser scanning with imaging data from low-cost cameras. The use of images from low-cost cameras makes it possible to limit the costs needed to complete such a study, and thus, increasing the possibility of intensifying the frequency of photographing and monitoring of the given structure. As a result, the analysed cultural heritage structures can be monitored more closely and in more detail, meaning that the technical documentation concerning this structure is also more precise. To supplement the laser scanning information, the Authors propose using both images taken both in the near-infrared range and in the visible range. This choice is motivated by the fact that not all important features of historical structures are always visible RGB, but they can be identified in NIR imagery, which, with the additional merging with a three-dimensional point cloud, gives full spatial information about the cultural heritage structure in question. The Authors proposed an algorithm that automates the process of integrating NIR images with a point cloud using parameters, which had been calculated during the transformation of RGB images. A number of conditions affecting the accuracy of the texturing had been studies, in particular, the impact of the geometry of the distribution of adjustment points and their amount on the accuracy of the integration process, the correlation between the intensity value and the error on specific points using images in different ranges of the electromagnetic spectrum and the selection

  18. Integration of Point Clouds and Images Acquired from a Low-Cost NIR Camera Sensor for Cultural Heritage Purposes

    Science.gov (United States)

    Kedzierski, M.; Walczykowski, P.; Wojtkowska, M.; Fryskowska, A.

    2017-08-01

    Terrestrial Laser Scanning is currently one of the most common techniques for modelling and documenting structures of cultural heritage. However, only geometric information on its own, without the addition of imagery data is insufficient when formulating a precise statement about the status of studies structure, for feature extraction or indicating the sites to be restored. Therefore, the Authors propose the integration of spatial data from terrestrial laser scanning with imaging data from low-cost cameras. The use of images from low-cost cameras makes it possible to limit the costs needed to complete such a study, and thus, increasing the possibility of intensifying the frequency of photographing and monitoring of the given structure. As a result, the analysed cultural heritage structures can be monitored more closely and in more detail, meaning that the technical documentation concerning this structure is also more precise. To supplement the laser scanning information, the Authors propose using both images taken both in the near-infrared range and in the visible range. This choice is motivated by the fact that not all important features of historical structures are always visible RGB, but they can be identified in NIR imagery, which, with the additional merging with a three-dimensional point cloud, gives full spatial information about the cultural heritage structure in question. The Authors proposed an algorithm that automates the process of integrating NIR images with a point cloud using parameters, which had been calculated during the transformation of RGB images. A number of conditions affecting the accuracy of the texturing had been studies, in particular, the impact of the geometry of the distribution of adjustment points and their amount on the accuracy of the integration process, the correlation between the intensity value and the error on specific points using images in different ranges of the electromagnetic spectrum and the selection of the optimal

  19. Magnetic resonance imaging depiction of acquired Dyke-Davidoff-Masson syndrome with crossed cerebro-cerebellar diaschisis: Report of two cases.

    Science.gov (United States)

    Gupta, Ranjana; Joshi, Sandeep; Mittal, Amit; Luthra, Ishita; Mittal, Puneet; Verma, Vibha

    2015-01-01

    Acquired Dyke-Davidoff-Masson syndrome, also known as hemispheric atrophy, is characterized by loss of volume of one cerebral hemisphere from an insult in early life. Crossed cerebellar diaschisis refers to dysfunction/atrophy of cerebellar hemisphere which is secondary to contralateral supratentorial insult. We describe magnetic resonance imaging findings in two cases of acquired Dyke-Davidoff-Masson syndrome with crossed cerebro-cerebellar diaschisis.

  20. On-board processing of video image sequences

    DEFF Research Database (Denmark)

    Andersen, Jakob Dahl; Chanrion, Olivier Arnaud; Forchhammer, Søren

    2008-01-01

    and evaluated. On-board there are six video cameras each capturing images of 1024times1024 pixels of 12 bpp at a frame rate of 15 fps, thus totalling 1080 Mbits/s. In comparison the average downlink data rate for these images is projected to be 50 kbit/s. This calls for efficient on-board processing to select...

  1. Clinical evaluation of FMPSPGR sequence of the brain MR imaging

    International Nuclear Information System (INIS)

    Takahashi, Mitsuyuki; Hasegawa, Makoto; Mori, Naohiko; Yamanoguchi, Minoru; Matsubara, Tadashi

    1998-01-01

    In order to apply the FMPSPGR (fast multi planar spoiled GRASS) method to diagnose brain diseases, authors obtained the optimal condition for imaging by the phantom experiments and examined the clinical usefulness. Six kinds of the phantom, which were 4 of diluted Gd solution with different concentrations, olive oil and physiological saline solution were used. From the phantom experiments, TR/TE/FR=300/3.3/90 degrees was the optimal condition. The evaluation of the clinical images was performed on the same section by the ST method and the FMPSPGR method. Fifteen patients (9 men and 6 women, aged from 17 to 80 years) suspected of brain diseases were examined, including 8 of cerebral infarction, 1 of pontine infarction, 1 of brain contusion, 1 of intracerebral bleeding and 4 of brain tumors. Four cases of brain tumor were evaluated on the contrast imaging and the others were on the plain imaging. In the plain imaging, the FMPSPGR method was better than the SE method on the low signal region in the T1 weighted imaging. Furthermore, in the contrast imaging, it could give more clear images of the lesion in anterior cranial pit by suppressing artifacts of blood flow. The present results indicate that the FMPSPGR method is useful to diagnose brain diseases. (K.H.)

  2. Image registration based on virtual frame sequence analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chen, H.; Ng, W.S. [Nanyang Technological University, Computer Integrated Medical Intervention Laboratory, School of Mechanical and Aerospace Engineering, Singapore (Singapore); Shi, D. (Nanyang Technological University, School of Computer Engineering, Singapore, Singpore); Wee, S.B. [Tan Tock Seng Hospital, Department of General Surgery, Singapore (Singapore)

    2007-08-15

    This paper is to propose a new framework for medical image registration with large nonrigid deformations, which still remains one of the biggest challenges for image fusion and further analysis in many medical applications. Registration problem is formulated as to recover a deformation process with the known initial state and final state. To deal with large nonlinear deformations, virtual frames are proposed to be inserted to model the deformation process. A time parameter is introduced and the deformation between consecutive frames is described with a linear affine transformation. Experiments are conducted with simple geometric deformation as well as complex deformations presented in MRI and ultrasound images. All the deformations are characterized with nonlinearity. The positive results demonstrated the effectiveness of this algorithm. The framework proposed in this paper is feasible to register medical images with large nonlinear deformations and is especially useful for sequential images. (orig.)

  3. Chloroplast DNA sequence of the green alga Oedogonium cardiacum (Chlorophyceae: Unique genome architecture, derived characters shared with the Chaetophorales and novel genes acquired through horizontal transfer

    Directory of Open Access Journals (Sweden)

    Lemieux Claude

    2008-06-01

    Full Text Available Abstract Background To gain insight into the branching order of the five main lineages currently recognized in the green algal class Chlorophyceae and to expand our understanding of chloroplast genome evolution, we have undertaken the sequencing of chloroplast DNA (cpDNA from representative taxa. The complete cpDNA sequences previously reported for Chlamydomonas (Chlamydomonadales, Scenedesmus (Sphaeropleales, and Stigeoclonium (Chaetophorales revealed tremendous variability in their architecture, the retention of only few ancestral gene clusters, and derived clusters shared by Chlamydomonas and Scenedesmus. Unexpectedly, our recent phylogenies inferred from these cpDNAs and the partial sequences of three other chlorophycean cpDNAs disclosed two major clades, one uniting the Chlamydomonadales and Sphaeropleales (CS clade and the other uniting the Oedogoniales, Chaetophorales and Chaetopeltidales (OCC clade. Although molecular signatures provided strong support for this dichotomy and for the branching of the Oedogoniales as the earliest-diverging lineage of the OCC clade, more data are required to validate these phylogenies. We describe here the complete cpDNA sequence of Oedogonium cardiacum (Oedogoniales. Results Like its three chlorophycean homologues, the 196,547-bp Oedogonium chloroplast genome displays a distinctive architecture. This genome is one of the most compact among photosynthetic chlorophytes. It has an atypical quadripartite structure, is intron-rich (17 group I and 4 group II introns, and displays 99 different conserved genes and four long open reading frames (ORFs, three of which are clustered in the spacious inverted repeat of 35,493 bp. Intriguingly, two of these ORFs (int and dpoB revealed high similarities to genes not usually found in cpDNA. At the gene content and gene order levels, the Oedogonium genome most closely resembles its Stigeoclonium counterpart. Characters shared by these chlorophyceans but missing in members

  4. Emergency Medicine Evaluation of Community-Acquired Pneumonia: History, Examination, Imaging and Laboratory Assessment, and Risk Scores.

    Science.gov (United States)

    Long, Brit; Long, Drew; Koyfman, Alex

    2017-11-01

    Pneumonia is a common infection, accounting for approximately one million hospitalizations in the United States annually. This potentially life-threatening disease is commonly diagnosed based on history, physical examination, and chest radiograph. To investigate emergency medicine evaluation of community-acquired pneumonia including history, physical examination, imaging, and the use of risk scores in patient assessment. Pneumonia is the number one cause of death from infectious disease. The condition is broken into several categories, the most common being community-acquired pneumonia. Diagnosis centers on history, physical examination, and chest radiograph. However, all are unreliable when used alone, and misdiagnosis occurs in up to one-third of patients. Chest radiograph has a sensitivity of 46-77%, and biomarkers including white blood cell count, procalcitonin, and C-reactive protein provide little benefit in diagnosis. Biomarkers may assist admitting teams, but require further study for use in the emergency department. Ultrasound has shown utility in correctly identifying pneumonia. Clinical gestalt demonstrates greater ability to diagnose pneumonia. Clinical scores including Pneumonia Severity Index (PSI); Confusion, blood Urea nitrogen, Respiratory rate, Blood pressure, age 65 score (CURB-65); and several others may be helpful for disposition, but should supplement, not replace, clinical judgment. Patient socioeconomic status must be considered in disposition decisions. The diagnosis of pneumonia requires clinical gestalt using a combination of history and physical examination. Chest radiograph may be negative, particularly in patients presenting early in disease course and elderly patients. Clinical scores can supplement clinical gestalt and assist in disposition when used appropriately. Published by Elsevier Inc.

  5. MR imaging of the orbit and eye using inversion recovery sequences

    International Nuclear Information System (INIS)

    Smith, F.W.; Parekh, S.; Forrester, J.; Redpath, T.W.

    1986-01-01

    Most centers performing MR imaging use spin-echo sequences to produce images; however, there are many advantages to using short TI inversion-recovery sequences for examination of the orbits. By selecting a TI similar to the relaxation time of any structure, the signal from this can be suppressed, thereby enhancing the signal from other structures. Using a sequence of TR = 1,000 msec and TI of less than 200 msec, the signal from fat is suppressed, improving image quality adjacent to the surface coil and providing better contrast between orbital structures and fat. The use of this short TI sequence for the examination of the eye in patients with opaque lenses is an accurate method of diagnosis since the sequence enhances the signal from both long T1 and T2 lesions. Eighty-five patients with orbital or ocular pathology have been studied, and the results demonstrate the usefulness of this technique for diagnosis

  6. Optimization of parameter values for complex pulse sequences by simulated annealing: application to 3D MP-RAGE imaging of the brain.

    Science.gov (United States)

    Epstein, F H; Mugler, J P; Brookeman, J R

    1994-02-01

    A number of pulse sequence techniques, including magnetization-prepared gradient echo (MP-GRE), segmented GRE, and hybrid RARE, employ a relatively large number of variable pulse sequence parameters and acquire the image data during a transient signal evolution. These sequences have recently been proposed and/or used for clinical applications in the brain, spine, liver, and coronary arteries. Thus, the need for a method of deriving optimal pulse sequence parameter values for this class of sequences now exists. Due to the complexity of these sequences, conventional optimization approaches, such as applying differential calculus to signal difference equations, are inadequate. We have developed a general framework for adapting the simulated annealing algorithm to pulse sequence parameter value optimization, and applied this framework to the specific case of optimizing the white matter-gray matter signal difference for a T1-weighted variable flip angle 3D MP-RAGE sequence. Using our algorithm, the values of 35 sequence parameters, including the magnetization-preparation RF pulse flip angle and delay time, 32 flip angles in the variable flip angle gradient-echo acquisition sequence, and the magnetization recovery time, were derived. Optimized 3D MP-RAGE achieved up to a 130% increase in white matter-gray matter signal difference compared with optimized 3D RF-spoiled FLASH with the same total acquisition time. The simulated annealing approach was effective at deriving optimal parameter values for a specific 3D MP-RAGE imaging objective, and may be useful for other imaging objectives and sequences in this general class.

  7. CT Image Sequence Restoration Based on Sparse and Low-Rank Decomposition

    Science.gov (United States)

    Gou, Shuiping; Wang, Yueyue; Wang, Zhilong; Peng, Yong; Zhang, Xiaopeng; Jiao, Licheng; Wu, Jianshe

    2013-01-01

    Blurry organ boundaries and soft tissue structures present a major challenge in biomedical image restoration. In this paper, we propose a low-rank decomposition-based method for computed tomography (CT) image sequence restoration, where the CT image sequence is decomposed into a sparse component and a low-rank component. A new point spread function of Weiner filter is employed to efficiently remove blur in the sparse component; a wiener filtering with the Gaussian PSF is used to recover the average image of the low-rank component. And then we get the recovered CT image sequence by combining the recovery low-rank image with all recovery sparse image sequence. Our method achieves restoration results with higher contrast, sharper organ boundaries and richer soft tissue structure information, compared with existing CT image restoration methods. The robustness of our method was assessed with numerical experiments using three different low-rank models: Robust Principle Component Analysis (RPCA), Linearized Alternating Direction Method with Adaptive Penalty (LADMAP) and Go Decomposition (GoDec). Experimental results demonstrated that the RPCA model was the most suitable for the small noise CT images whereas the GoDec model was the best for the large noisy CT images. PMID:24023764

  8. Elimination of motion and pulsation artifacts using BLADE sequences in shoulder MR imaging

    International Nuclear Information System (INIS)

    Lavdas, E.; Zaloni, E.; Vlychou, M.; Vassiou, K.; Fezoulidis, I.; Tsagkalis, A.; Dailiana, Z.

    2015-01-01

    To evaluate the ability of proton-density with fat-suppression BLADE (proprietary name for periodically rotated overlapping parallel lines with enhanced reconstruction in MR systems from Siemens Healthcare, PDFS BLADE) and turbo inversion recovery magnitude-BLADE (TIRM BLADE) sequences to reduce motion and pulsation artifacts in shoulder magnetic resonance examinations. Forty-one consecutive patients who had been routinely scanned for shoulder examination participated in the study. The following pairs of sequences with and without BLADE were compared: (a) Oblique coronal proton-density sequence with fat saturation of 25 patients and (b) oblique sagittal T2 TIRM-weighed sequence of 20 patients. Qualitative analysis was performed by two experienced radiologists. Image motion and pulsation artifacts were also evaluated. In oblique coronal PDFS BLADE sequences, motion artifacts have been significantly eliminated, even in five cases of non-diagnostic value with conventional imaging. Similarly, in oblique sagittal T2 TIRM BLADE sequences, image quality has been improved, even in six cases of non-diagnostic value with conventional imaging. Furthermore, flow artifacts have been improved in more than 80% of all the cases. The use of BLADE sequences is recommended in shoulder imaging, especially in uncooperative patients because it effectively eliminates motion and pulsation artifacts. (orig.)

  9. Motion Estimation Using the Firefly Algorithm in Ultrasonic Image Sequence of Soft Tissue

    Directory of Open Access Journals (Sweden)

    Chih-Feng Chao

    2015-01-01

    Full Text Available Ultrasonic image sequence of the soft tissue is widely used in disease diagnosis; however, the speckle noises usually influenced the image quality. These images usually have a low signal-to-noise ratio presentation. The phenomenon gives rise to traditional motion estimation algorithms that are not suitable to measure the motion vectors. In this paper, a new motion estimation algorithm is developed for assessing the velocity field of soft tissue in a sequence of ultrasonic B-mode images. The proposed iterative firefly algorithm (IFA searches for few candidate points to obtain the optimal motion vector, and then compares it to the traditional iterative full search algorithm (IFSA via a series of experiments of in vivo ultrasonic image sequences. The experimental results show that the IFA can assess the vector with better efficiency and almost equal estimation quality compared to the traditional IFSA method.

  10. Research on Image Encryption Based on DNA Sequence and Chaos Theory

    Science.gov (United States)

    Tian Zhang, Tian; Yan, Shan Jun; Gu, Cheng Yan; Ren, Ran; Liao, Kai Xin

    2018-04-01

    Nowadays encryption is a common technique to protect image data from unauthorized access. In recent years, many scientists have proposed various encryption algorithms based on DNA sequence to provide a new idea for the design of image encryption algorithm. Therefore, a new method of image encryption based on DNA computing technology is proposed in this paper, whose original image is encrypted by DNA coding and 1-D logistic chaotic mapping. First, the algorithm uses two modules as the encryption key. The first module uses the real DNA sequence, and the second module is made by one-dimensional logistic chaos mapping. Secondly, the algorithm uses DNA complementary rules to encode original image, and uses the key and DNA computing technology to compute each pixel value of the original image, so as to realize the encryption of the whole image. Simulation results show that the algorithm has good encryption effect and security.

  11. Diagnosing lung nodules on oncologic MR/PET imaging: Comparison of fast T1-weighted sequences and influence of image acquisition in inspiration and expiration breath-hold

    Energy Technology Data Exchange (ETDEWEB)

    Schwenzer, Nina F.; Seith, Ferdinand; Gatidis, Sergios; Brendle, Cornelia; Schmidt, Holger; Pfannenberg, Christina A; LaFougère, Christian; Nikolaou, Konstantin; Schraml, Christina [University Hospital of Tuebingen, Tuebingen (Germany)

    2016-09-15

    First, to investigate the diagnostic performance of fast T1-weighted sequences for lung nodule evaluation in oncologic magnetic resonance (MR)/positron emission tomography (PET). Second, to evaluate the influence of image acquisition in inspiration and expiration breath-hold on diagnostic performance. The study was approved by the local Institutional Review Board. PET/CT and MR/PET of 44 cancer patients were evaluated by 2 readers. PET/CT included lung computed tomography (CT) scans in inspiration and expiration (CTin, CTex). MR/PET included Dixon sequence for attenuation correction and fast T1-weighted volumetric interpolated breath-hold examination (VIBE) sequences (volume interpolated breath-hold examination acquired in inspiration [VIBEin], volume interpolated breath-hold examination acquired in expiration [VIBEex]). Diagnostic performance was analyzed for lesion-, lobe-, and size-dependence. Diagnostic confidence was evaluated (4-point Likert-scale; 1 = high). Jackknife alternative free-response receiver-operating characteristic (JAFROC) analysis was performed. Seventy-six pulmonary lesions were evaluated. Lesion-based detection rates were: CTex, 77.6%; VIBEin, 53.3%; VIBEex, 51.3%; and Dixon, 22.4%. Lobe-based detection rates were: CTex, 89.6%; VIBEin, 58.3%; VIBEex, 60.4%; and Dixon, 31.3%. In contrast to CT, inspiration versus expiration did not alter diagnostic performance in VIBE sequences. Diagnostic confidence was best for VIBEin and CTex and decreased in VIBEex and Dixon (1.2 ± 0.6; 1.2 ± 0.7; 1.5 ± 0.9; 1.7 ± 1.1, respectively). The JAFROC figure-of-merit of Dixon was significantly lower. All patients with malignant lesions were identified by CTex, VIBEin, and VIBEex, while 3 patients were false-negative in Dixon. Fast T1-weighted VIBE sequences allow for identification of patients with malignant pulmonary lesions. The Dixon sequence is not recommended for lung nodule evaluation in oncologic MR/PET patients. In contrast to CT, inspiration versus

  12. Diagnosing Lung Nodules on Oncologic MR/PET Imaging: Comparison of Fast T1-Weighted Sequences and Influence of Image Acquisition in Inspiration and Expiration Breath-Hold

    Energy Technology Data Exchange (ETDEWEB)

    Schwenzer, Nina F.; Seith, Ferdinand; Gatidis, Sergios [Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Tuebingen 72076 (Germany); Brendle, Cornelia [Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Tuebingen 72076 (Germany); Department of Diagnostic and Interventional Neuroradiology, University Hospital of Tuebingen, Tuebingen 72076 (Germany); Schmidt, Holger; Pfannenberg, Christina A. [Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Tuebingen 72076 (Germany); Fougère, Christian la [Department of Nuclear Medicine, University Hospital of Tuebingen, Tuebingen 72076 (Germany); Nikolaou, Konstantin; Schraml, Christina [Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Tuebingen 72076 (Germany)

    2016-11-01

    First, to investigate the diagnostic performance of fast T1-weighted sequences for lung nodule evaluation in oncologic magnetic resonance (MR)/positron emission tomography (PET). Second, to evaluate the influence of image acquisition in inspiration and expiration breath-hold on diagnostic performance. The study was approved by the local Institutional Review Board. PET/CT and MR/PET of 44 cancer patients were evaluated by 2 readers. PET/CT included lung computed tomography (CT) scans in inspiration and expiration (CTin, CTex). MR/PET included Dixon sequence for attenuation correction and fast T1-weighted volumetric interpolated breath-hold examination (VIBE) sequences (volume interpolated breath-hold examination acquired in inspiration [VIBEin], volume interpolated breath-hold examination acquired in expiration [VIBEex]). Diagnostic performance was analyzed for lesion-, lobe-, and size-dependence. Diagnostic confidence was evaluated (4-point Likert-scale; 1 = high). Jackknife alternative free-response receiver-operating characteristic (JAFROC) analysis was performed. Seventy-six pulmonary lesions were evaluated. Lesion-based detection rates were: CTex, 77.6%; VIBEin, 53.3%; VIBEex, 51.3%; and Dixon, 22.4%. Lobe-based detection rates were: CTex, 89.6%; VIBEin, 58.3%; VIBEex, 60.4%; and Dixon, 31.3%. In contrast to CT, inspiration versus expiration did not alter diagnostic performance in VIBE sequences. Diagnostic confidence was best for VIBEin and CTex and decreased in VIBEex and Dixon (1.2 ± 0.6; 1.2 ± 0.7; 1.5 ± 0.9; 1.7 ± 1.1, respectively). The JAFROC figure-of-merit of Dixon was significantly lower. All patients with malignant lesions were identified by CTex, VIBEin, and VIBEex, while 3 patients were false-negative in Dixon. Fast T1-weighted VIBE sequences allow for identification of patients with malignant pulmonary lesions. The Dixon sequence is not recommended for lung nodule evaluation in oncologic MR/PET patients. In contrast to CT, inspiration versus

  13. Outdoor Illumination Estimation in Image Sequences for Augmented Reality

    DEFF Research Database (Denmark)

    Madsen, Claus B.; Lal, Brajesh Behari

    2011-01-01

    the detected shadows is used to estimate the radiance of the sun. The technique does not require special purpose objects in the scene, nor does it require High Dynamic Range imagery. Results are demonstrated by rendering augmented objects into real images with shading and shadows which are consistent...

  14. Retrieval of Sentence Sequences for an Image Stream via Coherence Recurrent Convolutional Networks.

    Science.gov (United States)

    Park, Cesc Chunseong; Kim, Youngjin; Kim, Gunhee

    2018-04-01

    We propose an approach for retrieving a sequence of natural sentences for an image stream. Since general users often take a series of pictures on their experiences, much online visual information exists in the form of image streams, for which it would better take into consideration of the whole image stream to produce natural language descriptions. While almost all previous studies have dealt with the relation between a single image and a single natural sentence, our work extends both input and output dimension to a sequence of images and a sequence of sentences. For retrieving a coherent flow of multiple sentences for a photo stream, we propose a multimodal neural architecture called coherence recurrent convolutional network (CRCN), which consists of convolutional neural networks, bidirectional long short-term memory (LSTM) networks, and an entity-based local coherence model. Our approach directly learns from vast user-generated resource of blog posts as text-image parallel training data. We collect more than 22 K unique blog posts with 170 K associated images for the travel topics of NYC, Disneyland , Australia, and Hawaii. We demonstrate that our approach outperforms other state-of-the-art image captioning methods for text sequence generation, using both quantitative measures and user studies via Amazon Mechanical Turk.

  15. In vivo quantitative NMR imaging of fruit tissues during growth using Spoiled Gradient Echo sequence

    DEFF Research Database (Denmark)

    Kenouche, S.; Perrier, M.; Bertin, N.

    2014-01-01

    of this study was to design a robust and accurate quantitative measurement method based on NMR imaging combined with contrast agent (CA) for mapping and quantifying water transport in growing cherry tomato fruits. A multiple flip-angle Spoiled Gradient Echo (SGE) imaging sequence was used to evaluate...

  16. The role of the STIR sequence in magnetic resonance imaging examination of bone tumours

    International Nuclear Information System (INIS)

    Golfieri, R.; Baddeley, H.; Pringle, J.S.; Souhami, R.

    1990-01-01

    Sixty patients with primary bone tumours were evaluated with magnetic resonance imaging (MRI) at 0.5 T with both conventional spin-echo (SE) and short inversion time inversion recovery (STIR) sequences. The STIR sequence with T 1 of 120-130 ms in all cases suppressed the high signal from fatty bone marrow, giving a clear depiction of tumour extent, in both its intramedullary and soft-tissue components, and is superior to conventional SE images. The high sensitivity (100% of our cases) of this technique is counterbalanced by its lack of specificity: on STIR sequences both tumour and peritumorous oedema give an increase of signal intensity, limiting assessment of tumour extent. Peritumoral oedema, only present in this series in malignant neoplasms, may however be differentiated on the basis of the configuration of the abnormal areas, and by comparing STIR images with short repetition time/echo time sequence results. (author)

  17. Hybrid PET/MR imaging: an algorithm to reduce metal artifacts from dental implants in Dixon-based attenuation map generation using a multiacquisition variable-resonance image combination sequence.

    Science.gov (United States)

    Burger, Irene A; Wurnig, Moritz C; Becker, Anton S; Kenkel, David; Delso, Gaspar; Veit-Haibach, Patrick; Boss, Andreas

    2015-01-01

    It was the aim of this study to implement an algorithm modifying Dixon-based MR imaging datasets for attenuation correction in hybrid PET/MR imaging with a multiacquisition variable resonance image combination (MAVRIC) sequence to reduce metal artifacts. After ethics approval, in 8 oncologic patients with dental implants data were acquired in a trimodality setup with PET/CT and MR imaging. The protocol included a whole-body 3-dimensional dual gradient-echo sequence (Dixon) used for MR imaging-based PET attenuation correction and a high-resolution MAVRIC sequence, applied in the oral area compromised by dental implants. An algorithm was implemented correcting the Dixon-based μ maps using the MAVRIC in areas of Dixon signal voids. The artifact size of the corrected μ maps was compared with the uncorrected MR imaging μ maps. The algorithm was robust in all patients. There was a significant reduction in mean artifact size of 70.5% between uncorrected and corrected μ maps from 697 ± 589 mm(2) to 202 ± 119 mm(2) (P = 0.016). The proposed algorithm could improve MR imaging-based attenuation correction in critical areas, when standard attenuation correction is hampered by metal artifacts, using a MAVRIC. © 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

  18. Optimal pulse-sequence parameters for MR imaging of the immature brain

    International Nuclear Information System (INIS)

    Nowell, M.A.; Hackney, D.B.; Zimmerman, R.A.; Bilaniuk, L.T.; Grossman, R.I.; Goldberg, H.I.

    1986-01-01

    Appropriate spin-echo pulse sequence parameters generate MR images with very high gray matter/white matter contrast in neonates and young infants. Low-contrast images appear to result from utilization of ''adult-type'' parameters to investigate tissues that have relaxation characteristics quite different than those of adult brain. In these young patients long spin-echo sequences with repetition times of 3,000-3,500 msec and multiple echoes with the longest echo time set at 120-160 msec are employed to yield high-contrast ''T2-weighted'' images

  19. Investigation and identification of etiologies involved in the development of acquired hydronephrosis in aged laboratory mice with the use of high-frequency ultrasound imaging

    Science.gov (United States)

    Springer, Danielle A.; Allen, Michele; Hoffman, Victoria; Brinster, Lauren; Starost, Matthew F.; Bryant, Mark; Eckhaus, Michael

    2014-01-01

    Laboratory mice develop naturally occurring lesions that affect biomedical research. Hydronephrosis is a recognized pathologic abnormality of the mouse kidney. Acquired hydronephrosis can affect any mouse, as it is caused by any naturally occurring disease that impairs free urine flow. Many etiologies leading to this condition are of particular significance to aging mice. Non-invasive ultrasound imaging detects renal pelvic dilation, renal enlargement, and parenchymal loss for pre-mortem identification of this condition. High-frequency ultrasound transducers produce high-resolution images of small structures, ideal for detecting organ pathology in mice. Using a 40 MHz linear array transducer, we obtained high-resolution images of a diversity of pathologic lesions occurring within the abdomen of seven geriatric mice with acquired hydronephrosis that enabled a determination of the underlying etiology. Etiologies diagnosed from the imaging results include pyelonephritis, neoplasia, urolithiasis, mouse urologic syndrome, and spontaneous hydronephrosis, and were confirmed at necropsy. A retrospective review of abdominal scans from an additional 149 aging mice shows that the most common etiologies associated with acquired hydronephrosis are mouse urologic syndrome and abdominal neoplasia. This report highlights the utility of high-frequency ultrasound for surveying research mice for age-related pathology, and is the first comprehensive report of multiple cases of acquired hydronephrosis in mice. PMID:25143818

  20. Optimal context quantization in lossless compression of image data sequences

    DEFF Research Database (Denmark)

    Forchhammer, Søren; Wu, X.; Andersen, Jakob Dahl

    2004-01-01

    In image compression context-based entropy coding is commonly used. A critical issue to the performance of context-based image coding is how to resolve the conflict of a desire for large templates to model high-order statistic dependency of the pixels and the problem of context dilution due...... to insufficient sample statistics of a given input image. We consider the problem of finding the optimal quantizer Q that quantizes the K-dimensional causal context C/sub t/=(X/sub t-t1/,X/sub t-t2/,...,X/sub t-tK/) of a source symbol X/sub t/ into one of a set of conditioning states. The optimality of context...... quantization is defined to be the minimum static or minimum adaptive code length of given a data set. For a binary source alphabet an optimal context quantizer can be computed exactly by a fast dynamic programming algorithm. Faster approximation solutions are also proposed. In case of m-ary source alphabet...

  1. An efficient sequence for fetal brain imaging at 3T with enhanced T1 contrast and motion robustness.

    Science.gov (United States)

    Ferrazzi, Giulio; Price, Anthony N; Teixeira, Rui Pedro A G; Cordero-Grande, Lucilio; Hutter, Jana; Gomes, Ana; Padormo, Francesco; Hughes, Emer; Schneider, Torben; Rutherford, Mary; Kuklisova Murgasova, Maria; Hajnal, Joseph V

    2018-07-01

    Ultrafast single-shot T 2 -weighted images are common practice in fetal MR exams. However, there is limited experience with fetal T 1 -weighted acquisitions. This study aims at establishing a robust framework that allows fetal T 1 -weighted scans to be routinely acquired in utero at 3T. A 2D gradient echo sequence with an adiabatic inversion was optimized to be robust to fetal motion and maternal breathing optimizing grey/white matter contrast at the same time. This was combined with slice to volume registration and super resolution methods to produce volumetric reconstructions. The sequence was tested on 22 fetuses. Optimized grey/white matter contrast and robustness to fetal motion and maternal breathing were achieved. Signal from cerebrospinal fluid (CSF) and amniotic fluid was nulled and 0.75 mm isotropic anatomical reconstructions of the fetal brain were obtained using slice-to-volume registration and super resolution techniques. Total acquisition time for a single stack was 56 s, all acquired during free breathing. Enhanced sensitivity to normal anatomy and pathology with respect to established methods is demonstrated. A direct comparison with a 3D spoiled gradient echo sequence and a controlled motion experiment run on an adult volunteer are also shown. This paper describes a robust framework to perform T 1 -weighted acquisitions and reconstructions of the fetal brain in utero. Magn Reson Med 80:137-146, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic

  2. High-accuracy and robust face recognition system based on optical parallel correlator using a temporal image sequence

    Science.gov (United States)

    Watanabe, Eriko; Ishikawa, Mami; Ohta, Maiko; Kodate, Kashiko

    2005-09-01

    Face recognition is used in a wide range of security systems, such as monitoring credit card use, searching for individuals with street cameras via Internet and maintaining immigration control. There are still many technical subjects under study. For instance, the number of images that can be stored is limited under the current system, and the rate of recognition must be improved to account for photo shots taken at different angles under various conditions. We implemented a fully automatic Fast Face Recognition Optical Correlator (FARCO) system by using a 1000 frame/s optical parallel correlator designed and assembled by us. Operational speed for the 1: N (i.e. matching a pair of images among N, where N refers to the number of images in the database) identification experiment (4000 face images) amounts to less than 1.5 seconds, including the pre/post processing. From trial 1: N identification experiments using FARCO, we acquired low error rates of 2.6% False Reject Rate and 1.3% False Accept Rate. By making the most of the high-speed data-processing capability of this system, much more robustness can be achieved for various recognition conditions when large-category data are registered for a single person. We propose a face recognition algorithm for the FARCO while employing a temporal image sequence of moving images. Applying this algorithm to a natural posture, a two times higher recognition rate scored compared with our conventional system. The system has high potential for future use in a variety of purposes such as search for criminal suspects by use of street and airport video cameras, registration of babies at hospitals or handling of an immeasurable number of images in a database.

  3. Novel sequence types of extended-spectrum and acquired AmpC beta-lactamase producing Escherichia coli and Escherichia clade V isolated from wild mammals.

    Science.gov (United States)

    Alonso, Carla Andrea; Alcalá, Leticia; Simón, Carmen; Torres, Carmen

    2017-08-01

    The closer contact with wildlife due to the growing human population and the destruction of natural habitats emphasizes the need of gaining insight into the role of animals as source of antimicrobial resistance. Here, we aim at characterizing the antimicrobial resistance genes and phylogenetic distribution of commensal Escherichia coli from 62 wild mammals. Isolates exhibiting resistance to ≥1 antibiotic were detected in 25.8% of the animals and 6.4% carried an extended-spectrum beta-lactamase (ESBL)/AmpC-producing E. coli. Genetic mechanisms involved in third-generation cephalosporin resistance were as follows: (i) hyperproduction of chromosomal AmpC (hedgehog), (ii) production of acquired CMY-2 β-lactamase (hedgehog), (iii) production of SHV-12 and CTX-M-14 ESBLs (n = 2, mink and roe-deer). ESBL genes were transferable by conjugation, and blaCMY-2 was mobilized by a 95kb IncI1 plasmid. The distribution of the phylogenetic groups in the E. coli collection studied was B1 (44.6%), B2 (24.6%), E (15.4%), A (4.6%) and F (3.1%). Five isolates (7.7%) were cryptic Escherichia clades (clade IV, 4 mice; clade V, 1 mink). ESBL/AmpC-E. coli isolates showed different sequence types (STs): ST1128/B1, ST4564/B1 (new), ST4996/B1 (new) and a non-registered ST. This study contributes to better understand the E. coli population and antimicrobial resistance flow in wildlife and reports new AmpC-E. coli STs and a first described ESBL-producing Escherichia clade V isolate. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  4. Estimation of physiological parameters using knowledge-based factor analysis of dynamic nuclear medicine image sequences

    International Nuclear Information System (INIS)

    Yap, J.T.; Chen, C.T.; Cooper, M.

    1995-01-01

    The authors have previously developed a knowledge-based method of factor analysis to analyze dynamic nuclear medicine image sequences. In this paper, the authors analyze dynamic PET cerebral glucose metabolism and neuroreceptor binding studies. These methods have shown the ability to reduce the dimensionality of the data, enhance the image quality of the sequence, and generate meaningful functional images and their corresponding physiological time functions. The new information produced by the factor analysis has now been used to improve the estimation of various physiological parameters. A principal component analysis (PCA) is first performed to identify statistically significant temporal variations and remove the uncorrelated variations (noise) due to Poisson counting statistics. The statistically significant principal components are then used to reconstruct a noise-reduced image sequence as well as provide an initial solution for the factor analysis. Prior knowledge such as the compartmental models or the requirement of positivity and simple structure can be used to constrain the analysis. These constraints are used to rotate the factors to the most physically and physiologically realistic solution. The final result is a small number of time functions (factors) representing the underlying physiological processes and their associated weighting images representing the spatial localization of these functions. Estimation of physiological parameters can then be performed using the noise-reduced image sequence generated from the statistically significant PCs and/or the final factor images and time functions. These results are compared to the parameter estimation using standard methods and the original raw image sequences. Graphical analysis was performed at the pixel level to generate comparable parametric images of the slope and intercept (influx constant and distribution volume)

  5. Comparison of 3 T and 7 T MRI clinical sequences for ankle imaging

    Energy Technology Data Exchange (ETDEWEB)

    Juras, Vladimir, E-mail: vladimir.juras@meduniwien.ac.at [Medical University of Vienna, Department of Radiology, Vienna General Hospital, Waeringer Guertel 18-20, A-1090 Vienna (Austria); Slovak Academy of Sciences, Institute of Measurement Science, Dubravska cesta 9, 84104 Bratislava (Slovakia); Welsch, Goetz, E-mail: welsch@bwh.harvard.edu [Medical University of Vienna, Department of Radiology, Vienna General Hospital, Waeringer Guertel 18-20, A-1090 Vienna (Austria); Baer, Peter, E-mail: baerpeter@siemens.com [Siemens Healthcare, Richard-Strauss-Strasse 76, D81679 Munich (Germany); Kronnerwetter, Claudia, E-mail: claudia.kronnerwetter@meduniwien.ac.at [Medical University of Vienna, Department of Radiology, Vienna General Hospital, Waeringer Guertel 18-20, A-1090 Vienna (Austria); Fujita, Hiroyuki, E-mail: hiroyuki.fujita@qualedyn.com [Quality Electrodynamics, LCC, 777 Beta Dr, Cleveland, OH 44143-2336 (United States); Trattnig, Siegfried, E-mail: siegfried.trattnig@meduniwien.ac.at [Medical University of Vienna, Department of Radiology, Vienna General Hospital, Waeringer Guertel 18-20, A-1090 Vienna (Austria)

    2012-08-15

    The purpose of this study was to compare 3 T and 7 T signal-to-noise and contrast-to noise ratios of clinical sequences for imaging of the ankles with optimized sequences and dedicated coils. Ten healthy volunteers were examined consecutively on both systems with three clinical sequences: (1) 3D gradient-echo, T{sub 1}-weighted; (2) 2D fast spin-echo, PD-weighted; and (3) 2D spin-echo, T{sub 1}-weighted. SNR was calculated for six regions: cartilage; bone; muscle; synovial fluid; Achilles tendon; and Kager's fat-pad. CNR was obtained for cartilage/bone, cartilage/fluid, cartilage/muscle, and muscle/fat-pad, and compared by a one-way ANOVA test for repeated measures. Mean SNR significantly increased at 7 T compared to 3 T for 3D GRE, and 2D TSE was 60.9% and 86.7%, respectively. In contrast, an average SNR decrease of almost 25% was observed in the 2D SE sequence. A CNR increase was observed in 2D TSE images, and in most 3D GRE images. There was a substantial benefit from ultra high-field MR imaging of ankles with routine clinical sequences at 7 T compared to 3 T. Higher SNR and CNR at ultra-high field MR scanners may be useful in clinical practice for ankle imaging. However, carefully optimized protocols and dedicated extremity coils are necessary to obtain optimal results.

  6. MRI investigation of normal fetal lung maturation using signal intensities on different imaging sequences

    International Nuclear Information System (INIS)

    Balassy, Csilla; Kasprian, Gregor; Weber, Michael; Hoermann, Marcus; Prayer, Daniela; Brugger, Peter C.; Csapo, Bence; Mittermayer, Christoph

    2007-01-01

    To purpose of this paper is to study the relation between normal lung maturation signal and changes in intensity ratios (SIR) and to determine which magnetic resonance imaging sequence provides the strongest correlation of normal lung SIs with gestational age. 126 normal singleton pregnancies (20-37 weeks) were examined with a 1.5 Tesla unit. Mean SIs for lungs, liver, and gastric fluid were assessed on six different sequences, and SIRs of lung/liver (LLSIR) and lung/gastric fluid (LGSIR) were correlated with gestational age for each sequence. To evaluate the feasibility of SIRs in the prediction of the state of the lung maturity, accuracy of the predicted SIRs (D*) was measured by calculating relative residuals (D*-D)/D for each sequence. LLSIRs showed significant changes in every sequence (p<0.05), while LGSIRs only on two sequences. Significant differences were shown for the mean of absolute residuals for both LLSIRs (p<0.001) and for LGSIRs (p=0.003). Relative residuals of LLSIRs were significantly smaller on T1-weighted sequence, whereas they were significantly higher for LGSIRs on FLAIR sequence. Fetal liver seems to be adequate reference for the investigation of lung maturation. T1-weighted sequence was the most accurate for the measurement of the lung SIs; thus, we propose to determine LLSIR on T1-weighted sequence when evaluating lung development. (orig.)

  7. MRI investigation of normal fetal lung maturation using signal intensities on different imaging sequences

    Energy Technology Data Exchange (ETDEWEB)

    Balassy, Csilla; Kasprian, Gregor; Weber, Michael; Hoermann, Marcus; Prayer, Daniela [Medical University of Vienna, Department of Radiology, Vienna (Austria); Brugger, Peter C. [Medical University of Vienna, Center of Anatomy and Cell Biology, Vienna (Austria); Csapo, Bence [Medical University of Vienna, Department of Obstetrics and Gyneocology, Vienna (Austria); Mittermayer, Christoph [Medical University of Vienna, Department of Pediatrics, Vienna (Austria)

    2007-03-15

    To purpose of this paper is to study the relation between normal lung maturation signal and changes in intensity ratios (SIR) and to determine which magnetic resonance imaging sequence provides the strongest correlation of normal lung SIs with gestational age. 126 normal singleton pregnancies (20-37 weeks) were examined with a 1.5 Tesla unit. Mean SIs for lungs, liver, and gastric fluid were assessed on six different sequences, and SIRs of lung/liver (LLSIR) and lung/gastric fluid (LGSIR) were correlated with gestational age for each sequence. To evaluate the feasibility of SIRs in the prediction of the state of the lung maturity, accuracy of the predicted SIRs (D*) was measured by calculating relative residuals (D*-D)/D for each sequence. LLSIRs showed significant changes in every sequence (p<0.05), while LGSIRs only on two sequences. Significant differences were shown for the mean of absolute residuals for both LLSIRs (p<0.001) and for LGSIRs (p=0.003). Relative residuals of LLSIRs were significantly smaller on T1-weighted sequence, whereas they were significantly higher for LGSIRs on FLAIR sequence. Fetal liver seems to be adequate reference for the investigation of lung maturation. T1-weighted sequence was the most accurate for the measurement of the lung SIs; thus, we propose to determine LLSIR on T1-weighted sequence when evaluating lung development. (orig.)

  8. Use of the Discrete Cosine Transform for the restoration of an image sequence

    International Nuclear Information System (INIS)

    Acheroy, M.P.J.

    1985-01-01

    The Discrete Cosine Transform (DCT) is recognized as an important tool for image compression techniques. Its use in image restoration is, however, not well known. It is the aim of this paper to provide a restoration method for a sequence of images using the DCT as well for the deblurring as for the noise reduction. It is shown that the DCT can play an interesting role in the deconvolution problem for linear imaging systems with finite, invariant and symmetric impulse response. It is further shown that the noise reduction can be performed onto an image sequence using a time adaptive Kalman filter in the domain of the Karhunen-Loeve transform which is approximated by the DCT

  9. Meteor localization via statistical analysis of spatially temporal fluctuations in image sequences

    Science.gov (United States)

    Kukal, Jaromír.; Klimt, Martin; Šihlík, Jan; Fliegel, Karel

    2015-09-01

    Meteor detection is one of the most important procedures in astronomical imaging. Meteor path in Earth's atmosphere is traditionally reconstructed from double station video observation system generating 2D image sequences. However, the atmospheric turbulence and other factors cause spatially-temporal fluctuations of image background, which makes the localization of meteor path more difficult. Our approach is based on nonlinear preprocessing of image intensity using Box-Cox and logarithmic transform as its particular case. The transformed image sequences are then differentiated along discrete coordinates to obtain statistical description of sky background fluctuations, which can be modeled by multivariate normal distribution. After verification and hypothesis testing, we use the statistical model for outlier detection. Meanwhile the isolated outlier points are ignored, the compact cluster of outliers indicates the presence of meteoroids after ignition.

  10. Fat-saturated diffusion-weighted imaging with three-dimensional MP-RAGE sequence

    International Nuclear Information System (INIS)

    Numano, Tomokazu; Homma, Kazuhiro; Takahashi, Nobuyuki; Hirose, Takeshi

    2005-01-01

    Image misrepresentation due to chemical shifts can create image artifacts on MR images. Distinguishing the organization and affected area can be difficult due to the chemical shift artifacts. Chemical shift selective (CHESS) is a method of decreasing chemical shift artifacts. In this study we have developed a new sequence for fat-saturated three-dimensional diffusion weighted MR imaging. This imaging was done during in vivo studies using an animal experiment MR imaging system at 2.0 T. In this sequence a preparation phase with a ''CHESS-90 deg RF-Motion Proving Gradient (MPG-180 deg RF-MPG-90 deg RF pulse train) was used to sensitize the magnetization to fat-saturated diffusion. Centric k-space acquisition order is necessary to minimize saturation effects from tissues with short relaxation times. From experimental results obtained with a phantom, the effect of the diffusion weighting and the effect of the fat-saturation were confirmed. From rat experimental results, fat-saturated diffusion weighted image data (0.55 x 0.55 x 0.55 mm 3 : voxel size) were obtained. This sequence was useful for in vivo imaging. (author)

  11. Shadow Areas Robust Matching Among Image Sequence in Planetary Landing

    Science.gov (United States)

    Ruoyan, Wei; Xiaogang, Ruan; Naigong, Yu; Xiaoqing, Zhu; Jia, Lin

    2017-01-01

    In this paper, an approach for robust matching shadow areas in autonomous visual navigation and planetary landing is proposed. The approach begins with detecting shadow areas, which are extracted by Maximally Stable Extremal Regions (MSER). Then, an affine normalization algorithm is applied to normalize the areas. Thirdly, a descriptor called Multiple Angles-SIFT (MA-SIFT) that coming from SIFT is proposed, the descriptor can extract more features of an area. Finally, for eliminating the influence of outliers, a method of improved RANSAC based on Skinner Operation Condition is proposed to extract inliers. At last, series of experiments are conducted to test the performance of the approach this paper proposed, the results show that the approach can maintain the matching accuracy at a high level even the differences among the images are obvious with no attitude measurements supplied.

  12. Differential evolution optimization combined with chaotic sequences for image contrast enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Santos Coelho, Leandro dos [Industrial and Systems Engineering Graduate Program, LAS/PPGEPS, Pontifical Catholic University of Parana, PUCPR Imaculada Conceicao, 1155, 80215-901 Curitiba, Parana (Brazil)], E-mail: leandro.coelho@pucpr.br; Sauer, Joao Guilherme [Industrial and Systems Engineering Graduate Program, LAS/PPGEPS, Pontifical Catholic University of Parana, PUCPR Imaculada Conceicao, 1155, 80215-901 Curitiba, Parana (Brazil)], E-mail: joao.sauer@gmail.com; Rudek, Marcelo [Industrial and Systems Engineering Graduate Program, LAS/PPGEPS, Pontifical Catholic University of Parana, PUCPR Imaculada Conceicao, 1155, 80215-901 Curitiba, Parana (Brazil)], E-mail: marcelo.rudek@pucpr.br

    2009-10-15

    Evolutionary Algorithms (EAs) are stochastic and robust meta-heuristics of evolutionary computation field useful to solve optimization problems in image processing applications. Recently, as special mechanism to avoid being trapped in local minimum, the ergodicity property of chaotic sequences has been used in various designs of EAs. Three differential evolution approaches based on chaotic sequences using logistic equation for image enhancement process are proposed in this paper. Differential evolution is a simple yet powerful evolutionary optimization algorithm that has been successfully used in solving continuous problems. The proposed chaotic differential evolution schemes have fast convergence rate but also maintain the diversity of the population so as to escape from local optima. In this paper, the image contrast enhancement is approached as a constrained nonlinear optimization problem. The objective of the proposed chaotic differential evolution schemes is to maximize the fitness criterion in order to enhance the contrast and detail in the image by adapting the parameters using a contrast enhancement technique. The proposed chaotic differential evolution schemes are compared with classical differential evolution to two testing images. Simulation results on three images show that the application of chaotic sequences instead of random sequences is a possible strategy to improve the performance of classical differential evolution optimization algorithm.

  13. A novel color image encryption scheme using fractional-order hyperchaotic system and DNA sequence operations

    International Nuclear Information System (INIS)

    Zhang Li-Min; Sun Ke-Hui; Liu Wen-Hao; He Shao-Bo

    2017-01-01

    In this paper, Adomian decomposition method (ADM) with high accuracy and fast convergence is introduced to solve the fractional-order piecewise-linear (PWL) hyperchaotic system. Based on the obtained hyperchaotic sequences, a novel color image encryption algorithm is proposed by employing a hybrid model of bidirectional circular permutation and DNA masking. In this scheme, the pixel positions of image are scrambled by circular permutation, and the pixel values are substituted by DNA sequence operations. In the DNA sequence operations, addition and substraction operations are performed according to traditional addition and subtraction in the binary, and two rounds of addition rules are used to encrypt the pixel values. The simulation results and security analysis show that the hyperchaotic map is suitable for image encryption, and the proposed encryption algorithm has good encryption effect and strong key sensitivity. It can resist brute-force attack, statistical attack, differential attack, known-plaintext, and chosen-plaintext attacks. (paper)

  14. Small-target leak detection for a closed vessel via infrared image sequences

    Science.gov (United States)

    Zhao, Ling; Yang, Hongjiu

    2017-03-01

    This paper focus on a leak diagnosis and localization method based on infrared image sequences. Some problems on high probability of false warning and negative affect for marginal information are solved by leak detection. An experimental model is established for leak diagnosis and localization on infrared image sequences. The differential background prediction is presented to eliminate the negative affect of marginal information on test vessel based on a kernel regression method. A pipeline filter based on layering voting is designed to reduce probability of leak point false warning. A synthesize leak diagnosis and localization algorithm is proposed based on infrared image sequences. The effectiveness and potential are shown for developed techniques through experimental results.

  15. Time-resolved echo-shared parallel MRA of the lung: observer preference study of image quality in comparison with non-echo-shared sequences

    International Nuclear Information System (INIS)

    Fink, C.; Puderbach, M.; Zaporozhan, J.; Plathow, C.; Kauczor, H.-U.; Ley, S.

    2005-01-01

    The aim of this study was to evaluate the image quality of time-resolved echo-shared parallel MRA of the lung. The pulmonary vasculature of nine patients (seven females, two males; median age: 44 years) with pulmonary disease was examined using a time-resolved MRA sequence combining echo sharing with parallel imaging (time-resolved echo-shared angiography technique, or TREAT). The sharpness of the vessel borders, conspicuousness of peripheral lung vessels, artifact level, and overall image quality of TREAT was assessed independently by four readers in a side-by-side comparison with non-echo-shared time-resolved parallel MRA data (pMRA) previously acquired in the same patients. Furthermore, the SNR of pulmonary arteries (PA) and veins (PV) achieved with both pulse sequences was compared. The mean voxel size of TREAT MRA was decreased by 24% compared with the non-echo-shared MRA. Regarding the sharpness of the vessel borders, conspicuousness of peripheral lung vessels, and overall image quality the TREAT sequence was rated superior in 75-76% of all cases. If the TREAT images were preferred over the pMRA images, the advantage was rated as major in 61-71% of all cases. The level of artifacts was not increased with the TREAT sequence. The mean interobserver agreement for all categories ranged between fair (artifact level) and good (overall image quality). The maximum SNR of TREAT did not differ from non-echo-shared parallel MRA (PA: TREAT: 273±45; pMRA: 280±71; PV: TREAT: 273±33; pMRA: 258±62). TREAT achieves a higher spatial resolution than non-echo-shared parallel MRA which is also perceived as an improved image quality. (orig.)

  16. Parry-Romberg syndrome: findings in advanced magnetic resonance imaging sequences - case report

    Energy Technology Data Exchange (ETDEWEB)

    Paula, Rafael Alfenas de; Ribeiro, Bruno Niemeyer de Freitas, E-mail: alfenas85@gmail.com [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Hospital Universitario Clementino Fraga Filho; Bahia, Paulo Roberto Valle [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Dept. de radiologia; Ribeiro, Renato Niemeyer de Freitas [Hospital de Clinica de Jacarepagua, Rio de Janeiro, RJ (Brazil); Carvalho, Lais Balbi de [Universidade Presidente Antonio Carlos (Unipac), Juiz de Fora, MG (Brazil)

    2014-05-15

    Parry-Romberg syndrome is a rare disease characterized by progressive hemifacial atrophy associated with other systemic changes, including neurological symptoms. Currently, there are few studies exploring the utilization of advanced magnetic resonance sequences in the investigation of this disease. The authors report the case of a 45-year-old patient and describe the findings at structural magnetic resonance imaging and at advanced sequences, correlating them with pathophysiological data. (author)

  17. Denoising time-resolved microscopy image sequences with singular value thresholding

    Energy Technology Data Exchange (ETDEWEB)

    Furnival, Tom, E-mail: tjof2@cam.ac.uk; Leary, Rowan K., E-mail: rkl26@cam.ac.uk; Midgley, Paul A., E-mail: pam33@cam.ac.uk

    2017-07-15

    Time-resolved imaging in microscopy is important for the direct observation of a range of dynamic processes in both the physical and life sciences. However, the image sequences are often corrupted by noise, either as a result of high frame rates or a need to limit the radiation dose received by the sample. Here we exploit both spatial and temporal correlations using low-rank matrix recovery methods to denoise microscopy image sequences. We also make use of an unbiased risk estimator to address the issue of how much thresholding to apply in a robust and automated manner. The performance of the technique is demonstrated using simulated image sequences, as well as experimental scanning transmission electron microscopy data, where surface adatom motion and nanoparticle structural dynamics are recovered at rates of up to 32 frames per second. - Highlights: • Correlations in space and time are harnessed to denoise microscopy image sequences. • A robust estimator provides automated selection of the denoising parameter. • Motion tracking and automated noise estimation provides a versatile algorithm. • Application to time-resolved STEM enables study of atomic and nanoparticle dynamics.

  18. Inter frame motion estimation and its application to image sequence compression: an introduction

    International Nuclear Information System (INIS)

    Cremy, C.

    1996-01-01

    With the constant development of new communication technologies like, digital TV, teleconference, and the development of image analysis applications, there is a growing volume of data to manage. Compression techniques are required for the transmission and storage of these data. Dealing with original images would require the use of expansive high bandwidth communication devices and huge storage media. Image sequence compression can be achieved by means of interframe estimation that consists in retrieving redundant information relative to zones where there is little motion between two frames. This paper is an introduction to some motion estimation techniques like gradient techniques, pel-recursive, block-matching, and its application to image sequence compression. (Author) 17 refs

  19. Cardiac tumors: optimal cardiac MR sequences and spectrum of imaging appearances.

    LENUS (Irish Health Repository)

    O'Donnell, David H

    2012-02-01

    OBJECTIVE: This article reviews the optimal cardiac MRI sequences for and the spectrum of imaging appearances of cardiac tumors. CONCLUSION: Recent technologic advances in cardiac MRI have resulted in the rapid acquisition of images of the heart with high spatial and temporal resolution and excellent myocardial tissue characterization. Cardiac MRI provides optimal assessment of the location, functional characteristics, and soft-tissue features of cardiac tumors, allowing accurate differentiation of benign and malignant lesions.

  20. Limited-sequence magnetic resonance imaging in the evaluation of the ultrasonographically indeterminate pelvic mass

    Energy Technology Data Exchange (ETDEWEB)

    Chang, S.D. [Univ. of British Columbia, Vancouver Hospital and Helath Services Centre, Dept. of Radiology, Vancouver, British Columbia (Canada)]. E-mail: schang@vanhosp.bc.ca; Cooperberg, P.L.; Wong, A.D. [Univ. of British Columbia, St. Paul' s Hospital, Dept. of Radiology, Vancouver, British Columbia (Canada); Llewellyn, P.A. [Lion' s Gate Hospital, Dept. of Radiology, North Vancouver, British Columbia (Canada); Bilbey, J.H. [Royal Inland Hospital, Dept. of Radiology, Kamloops, British Columbia (Canada)

    2004-04-01

    To evaluate the usefulness of limited-sequence magnetic resonance imaging (MRI) in the elucidation of ultrasonographically indeterminate pelvic masses. This study focused only on pelvic masses in which the origin of the mass (uterine v. extrauterine) could not be determined by ultrasonography (US). The origin of a pelvic mass has clinical implications. A mass arising from the uterus is most likely to be a leiomyoma, which is a benign lesion, whereas an extrauterine mass will have a higher likelihood of malignancy and usually requires surgery. Eighty-one female patients whose pelvic mass was of indeterminate origin on US also underwent limited-sequence MRI of the pelvis. Most of the MRI examinations were performed on the same day as the US. Limited-sequence MRI sequences included a quick gradient-echoT{sub 1}-weighted localizer and a fast spin-echoT{sub 2}-weighted sequence. Final diagnoses were established by surgical pathology or by clinical and imaging follow-up. Limited-sequence MRI was helpful in 79 of the 81 cases (98%). Fifty-two of the 81 masses (64%) were leiomyomas. One was a leiomyosarcoma. The extrauterine masses (26/81 [32%]) were identified as 14 ovarian malignancies, 4 endometriomas, 3 dermoids, an ovarian fibroma, an infarcted fibrothecoma, an infarcted hemorrhagic cyst, a sigmoid diverticular abscess and a gastrointestinal stromal tumour of the ileum. In the other 2 cases (2/81 [2%]), the origin of the pelvic mass remained indeterminate. Both of these indeterminate masses showed low signal onT{sub 2}-weighted images and were interpreted as probable leiomyomas. They were not surgically removed but were followed clinically and had a stable course. Limited-sequence MRI is a quick and efficient way to further evaluate ultrasonographically indeterminate pelvic masses. Limited-sequence MRI of the pelvis can suffice, in these cases, without requiring a full MRI examination. (author)

  1. Limited-sequence magnetic resonance imaging in the evaluation of the ultrasonographically indeterminate pelvic mass

    International Nuclear Information System (INIS)

    Chang, S.D.; Cooperberg, P.L.; Wong, A.D.; Llewellyn, P.A.; Bilbey, J.H.

    2004-01-01

    To evaluate the usefulness of limited-sequence magnetic resonance imaging (MRI) in the elucidation of ultrasonographically indeterminate pelvic masses. This study focused only on pelvic masses in which the origin of the mass (uterine v. extrauterine) could not be determined by ultrasonography (US). The origin of a pelvic mass has clinical implications. A mass arising from the uterus is most likely to be a leiomyoma, which is a benign lesion, whereas an extrauterine mass will have a higher likelihood of malignancy and usually requires surgery. Eighty-one female patients whose pelvic mass was of indeterminate origin on US also underwent limited-sequence MRI of the pelvis. Most of the MRI examinations were performed on the same day as the US. Limited-sequence MRI sequences included a quick gradient-echoT 1 -weighted localizer and a fast spin-echoT 2 -weighted sequence. Final diagnoses were established by surgical pathology or by clinical and imaging follow-up. Limited-sequence MRI was helpful in 79 of the 81 cases (98%). Fifty-two of the 81 masses (64%) were leiomyomas. One was a leiomyosarcoma. The extrauterine masses (26/81 [32%]) were identified as 14 ovarian malignancies, 4 endometriomas, 3 dermoids, an ovarian fibroma, an infarcted fibrothecoma, an infarcted hemorrhagic cyst, a sigmoid diverticular abscess and a gastrointestinal stromal tumour of the ileum. In the other 2 cases (2/81 [2%]), the origin of the pelvic mass remained indeterminate. Both of these indeterminate masses showed low signal onT 2 -weighted images and were interpreted as probable leiomyomas. They were not surgically removed but were followed clinically and had a stable course. Limited-sequence MRI is a quick and efficient way to further evaluate ultrasonographically indeterminate pelvic masses. Limited-sequence MRI of the pelvis can suffice, in these cases, without requiring a full MRI examination. (author)

  2. Retrospective comparison of three-dimensional imaging sequences in the visualization of posterior fossa cranial nerves.

    Science.gov (United States)

    Ors, Suna; Inci, Ercan; Turkay, Rustu; Kokurcan, Atilla; Hocaoglu, Elif

    2017-12-01

    To compare efficancy of three-dimentional SPACE (sampling perfection with application-optimized contrasts using different flip-angle evolutions) and CISS (constructive interference in steady state) sequences in the imaging of the cisternal segments of cranial nerves V-XII. Temporal MRI scans from 50 patients (F:M ratio, 27:23; mean age, 44.5±15.9 years) admitted to our hospital with vertigo, tinnitus, and hearing loss were retrospectively analyzed. All patients had both CISS and SPACE sequences. Quantitative analysis of SPACE and CISS sequences was performed by measuring the ventricle-to-parenchyma contrast-to-noise ratio (CNR). Qualitative analysis of differences in visualization capability, image quality, and severity of artifacts was also conducted. A score ranging 'no artefact' to 'severe artefacts and unreadable' was used for the assessment of artifacts and from 'not visualized' to 'completely visualized' for the assesment of image quality, respectively. The distribution of variables was controlled by the Kolmogorov-Smirnov test. Samples t-test and McNemar's test were used to determine statistical significance. Rates of visualization of posterior fossa cranial nerves in cases of complete visualization were as follows: nerve V (100% for both sequences), nerve VI (94% in SPACE, 86% in CISS sequences), nerves VII-VIII (100% for both sequences), IX-XI nerve complex (96%, 88%); nerve XII (58%, 46%) (p<0.05). SPACE sequences showed fewer artifacts than CISS sequences (p<0.002). Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Prostate cancer in magnetic resonance imaging: diagnostic utilites of spectroscopic sequences

    International Nuclear Information System (INIS)

    Caivano, Rocchina; Cirillo, Patrizia; Lotumolo, Antonella; Fortunato, Giovanna; Zandolino, Alexis; Cammarota, Aldo; Balestra, Antonio; Macarini, Luca; Vita, Giulia

    2012-01-01

    The aim of our work is to determine the efficacy of a combined study 3 Tesla Magnetic Resonance Imaging (3T MRI), with phased-array coil, for the detection of prostate cancer using magnetic resonance spectroscopy (MRS) and diffusion-weighted images (DWI) in identifying doubt nodules. In this study, we prospectively studied 46 patients who consecutively underwent digital-rectal exploration for high doses of prostate specific antigen (PSA), as well as a MRI examination and a subsequent rectal biopsy. The study of magnetic resonance imaging was performed with a Philips Achieva 3T scanner and phased-array coil. The images were obtained with turbo spin-echo sequences T2-weighted images, T1-weighted before and after the administration of contrast medium, DWI sequences and 3D spectroscopic sequences. The ultrasound-guided prostate biopsy was performed approximately 15 days after the MRI. The data obtained from MR images and spectroscopy were correlated with histological data. MRI revealed sensitivity and specificity of 88% and 61% respectively and positive predictive value (PPV) of 73%, negative predicted value (NPV) of 81% and accuracy of 76%. In identifying the location of prostate cancer, the sensitivity of 3T MRS was 92%, with a specificity of 89%, PPV of 87%, NPV of 88% and accuracy of 87%; DWI showed a sensitivity of 88%, specificity of 61%, PPV of 73%, NPV of 81% and accuracy of 76%. The 3T MR study with phased-array coil and the use of DWI and spectroscopic sequences, in addition to T2-weighted sequences, revealed to be accurate in the diagnosis of prostate cancer and in the identification of nodules to be biopsied. It may be indicated as a resolute way before biopsy in patients with elevated PSA value and can be proposed in the staging and follow-up.

  4. No Reference Prediction of Quality Metrics for H.264 Compressed Infrared Image Sequences for UAV Applications

    DEFF Research Database (Denmark)

    Hossain, Kabir; Mantel, Claire; Forchhammer, Søren

    2018-01-01

    The framework for this research work is the acquisition of Infrared (IR) images from Unmanned Aerial Vehicles (UAV). In this paper we consider the No-Reference (NR) prediction of Full Reference Quality Metrics for Infrared (IR) video sequences which are compressed and thus distorted by an H.264...

  5. A generative Bezier curve model for surf-zone tracking in coastal image sequences

    CSIR Research Space (South Africa)

    Burke, Michael G

    2017-09-01

    Full Text Available This work introduces a generative Bezier curve model suitable for surf-zone curve tracking in coastal image sequences. The model combines an adaptive curve parametrised by control points governed by local random walks with a global sinusoidal motion...

  6. Diffusion tensor imaging. Theory, sequence optimization and application in Alzheimer's disease

    International Nuclear Information System (INIS)

    Stieltjes, B.; Schlueter, M.; Hahn, H.K.; Wilhelm, T.; Essig, M.

    2003-01-01

    Diffusion tensor imaging (DTI) offers an in vivo view into the microarchitecture of the brain. Furthermore it allows a three-dimensional reconstruction of fiber tracts. We will discuss the principles of DTI and possibilities for sequence optimization. Finally we will give an overview of DTI and its application in Alzheimer's disease. (orig.) [de

  7. PETRA, MSVAT-SPACE and SEMAC sequences for metal artefact reduction in dental MR imaging

    International Nuclear Information System (INIS)

    Hilgenfeld, Tim; Heil, Alexander; Bendszus, Martin; Prager, Marcel; Heiland, Sabine; Schwindling, Franz Sebastian; Rammelsberg, Peter; Nittka, Mathias; Grodzki, David

    2017-01-01

    Dental MRI is often impaired by artefacts due to metallic dental materials. Several sequences were developed to reduce susceptibility artefacts. Here, we evaluated a set of sequences for artefact reduction for dental MRI for the first time. Artefact volume, signal-to-noise ratio (SNR) and image quality were assessed on a 3-T MRI for pointwise encoding time reduction with radial acquisition (PETRA), multiple-slab acquisition with view angle tilting gradient, based on a sampling perfection with application-optimised contrasts using different flip angle evolution (SPACE) sequence (MSVAT-SPACE), slice-encoding for metal-artefact correction (SEMAC) and compared to a standard SPACE and a standard turbo-spin-echo (TSE) sequence. Field-of-view and acquisition times were chosen to enable in vivo application. Two implant-supported prostheses were tested (porcelain fused to metal non-precious alloy and monolithic zirconia). Smallest artefact was measured for TSE sequences with no difference between the standard TSE and the SEMAC. MSVAT-SPACE reduced artefacts about 56% compared to the standard SPACE. Effect of the PETRA was dependent on sample used. Image quality and SNR were comparable for all sequences except PETRA, which yielded poor results. There is no benefit in terms of artefact reduction for SEMAC compared to standard TSE. Usage of MSVAT-SPACE is advantageous since artefacts are reduced and higher resolution is achieved. (orig.)

  8. PETRA, MSVAT-SPACE and SEMAC sequences for metal artefact reduction in dental MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Hilgenfeld, Tim; Heil, Alexander; Bendszus, Martin [Heidelberg University Hospital, Department of Neuroradiology, Heidelberg (Germany); Prager, Marcel; Heiland, Sabine [Heidelberg University Hospital, Department of Neuroradiology, Heidelberg (Germany); Heidelberg University Hospital, Section of Experimental Radiology, Heidelberg (Germany); Schwindling, Franz Sebastian; Rammelsberg, Peter [Heidelberg University Hospital, Department of Prosthodontics, Heidelberg (Germany); Nittka, Mathias; Grodzki, David [Siemens Healthcare GmbH, Erlangen (Germany)

    2017-12-15

    Dental MRI is often impaired by artefacts due to metallic dental materials. Several sequences were developed to reduce susceptibility artefacts. Here, we evaluated a set of sequences for artefact reduction for dental MRI for the first time. Artefact volume, signal-to-noise ratio (SNR) and image quality were assessed on a 3-T MRI for pointwise encoding time reduction with radial acquisition (PETRA), multiple-slab acquisition with view angle tilting gradient, based on a sampling perfection with application-optimised contrasts using different flip angle evolution (SPACE) sequence (MSVAT-SPACE), slice-encoding for metal-artefact correction (SEMAC) and compared to a standard SPACE and a standard turbo-spin-echo (TSE) sequence. Field-of-view and acquisition times were chosen to enable in vivo application. Two implant-supported prostheses were tested (porcelain fused to metal non-precious alloy and monolithic zirconia). Smallest artefact was measured for TSE sequences with no difference between the standard TSE and the SEMAC. MSVAT-SPACE reduced artefacts about 56% compared to the standard SPACE. Effect of the PETRA was dependent on sample used. Image quality and SNR were comparable for all sequences except PETRA, which yielded poor results. There is no benefit in terms of artefact reduction for SEMAC compared to standard TSE. Usage of MSVAT-SPACE is advantageous since artefacts are reduced and higher resolution is achieved. (orig.)

  9. Optimal pulse sequence for ferumoxides-enhanced MR imaging used in the detection of hepatocellular carcinoma: a comparative study using seven pulse sequences

    International Nuclear Information System (INIS)

    Kim, Seung Hoon; Choi, Dongil; Lim, Jae Hoon; Lee, Won Jae; Jang, Hyun Jung; Lim, Kyo Keun; Lee, Soon Jin; Cho, Jae Min; Kim, Seung Kwon; Kim, Gab Chul

    2002-01-01

    To identify the optimal pulse sequence for ferumoxides-enhanced magnetic resonance (MR) imaging in the detection of hepatocelluar carcinomas (HCCs). Sixteen patients with 25 HCCs underwent MR imaging following intravenous infusion of ferumoxides. All MR studies were performed on a 1.5-T MR system, using a phased-array coil. Ferumoxides (Feridex IV) at a dose of 15 μmol/Kg was slowly infused intravenously, and axial images of seven sequences were obtained 30 minutes after the end of infusion. The MR protocol included fast spin-echo (FSE) with two echo times (TR3333-8571/TE18 and 90-117), singleshot FSE (SSFSE) with two echo times (TR∞/TE39 and 98), T2-weighted gradient-recalled acquisition in the steady state (GRASS) (TR216/TE20), T2-weighted fast multiplanar GRASS (FMPGR) (TR130/TE8.4-9.5), and T2-weighted fast multiplanar spoiled GRASS (FMPSPGR) (TR130/TE8.4-9.5). Contrast-to-noise ratios (CNRs) of HCCs determined during the imaging sequences formed the basis of quantitative analysis, and images were qualitatively assessed in terms of lesion conspicuity and image artifacts. The diagnostic accuracy of all sequences was assessed using receiver operating characteristic (ROC) analysis. Quantitative analysis revealed that the CNRs of T2-weighted FMPGR and T2-weighted FMPSPGR were significantly higher than those of the other sequences, while qualitative analysis showed that image artifacts were prominent at T2-weighted GRASS imaging. Lesion conspicuity was statistically significantly less clear at SSFSE imaging. In term of lesion detection, T-weighted FMPGR, T2- weighted FMPSPGR, and proton density FSE imaging were statistically superior to the others. T2-weighted FMPGR, T2- weighted FMPSPGR, and proton density FSE appear to be the optimal pulse sequences for ferumoxidesenhanced MR imaging in the detection of HCCs

  10. Semiautomatic segmentation of aortic valve from sequenced ultrasound image using a novel shape-constraint GCV model

    International Nuclear Information System (INIS)

    Guo, Yiting; Dong, Bin; Wang, Bing; Xie, Hongzhi; Zhang, Shuyang; Gu, Lixu

    2014-01-01

    Purpose: Effective and accurate segmentation of the aortic valve (AV) from sequenced ultrasound (US) images remains a technical challenge because of intrinsic factors of ultrasound images that impact the quality and the continuous changes of shape and position of segmented objects. In this paper, a novel shape-constraint gradient Chan-Vese (GCV) model is proposed for segmenting the AV from time serial echocardiography. Methods: The GCV model is derived by incorporating the energy of the gradient vector flow into a CV model framework, where the gradient vector energy term is introduced by calculating the deviation angle between the inward normal force of the evolution contour and the gradient vector force. The flow force enlarges the capture range and enhances the blurred boundaries of objects. This is achieved by adding a circle-like contour (constructed using the AV structure region as a constraint shape) as an energy item to the GCV model through the shape comparison function. This shape-constrained energy can enhance the image constraint force by effectively connecting separate gaps of the object edge as well as driving the evolution contour to quickly approach the ideal object. Because of the slight movement of the AV in adjacent frames, the initial constraint shape is defined by users, with the other constraint shapes being derived from the segmentation results of adjacent sequence frames after morphological filtering. The AV is segmented from the US images by minimizing the proposed energy function. Results: To evaluate the performance of the proposed method, five assessment parameters were used to compare it with manual delineations performed by radiologists (gold standards). Three hundred and fifteen images acquired from nine groups were analyzed in the experiment. The area-metric overlap error rate was 6.89% ± 2.88%, the relative area difference rate 3.94% ± 2.63%, the average symmetric contour distance 1.08 ± 0.43 mm, the root mean square symmetric

  11. Semiautomatic segmentation of aortic valve from sequenced ultrasound image using a novel shape-constraint GCV model

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Yiting [Multi-disciplinary Research Center, Hebei University, Baoding 071000 (China); Dong, Bin [Hebei University Affiliated Hospital, Hebei Baoding 071000 (China); Wang, Bing [College of Mathematics and Computer Science, Hebei University, Baoding 071000 (China); Xie, Hongzhi, E-mail: xiehongzhi@medmail.com.cn, E-mail: gulixu@sjtu.edu.cn; Zhang, Shuyang [Department of Cardiovascular, Peking Union Medical College Hospital, Beijing 100005 (China); Gu, Lixu, E-mail: xiehongzhi@medmail.com.cn, E-mail: gulixu@sjtu.edu.cn [Multi-disciplinary Research Center, Hebei University, Baoding 071000, China and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030 (China)

    2014-07-15

    Purpose: Effective and accurate segmentation of the aortic valve (AV) from sequenced ultrasound (US) images remains a technical challenge because of intrinsic factors of ultrasound images that impact the quality and the continuous changes of shape and position of segmented objects. In this paper, a novel shape-constraint gradient Chan-Vese (GCV) model is proposed for segmenting the AV from time serial echocardiography. Methods: The GCV model is derived by incorporating the energy of the gradient vector flow into a CV model framework, where the gradient vector energy term is introduced by calculating the deviation angle between the inward normal force of the evolution contour and the gradient vector force. The flow force enlarges the capture range and enhances the blurred boundaries of objects. This is achieved by adding a circle-like contour (constructed using the AV structure region as a constraint shape) as an energy item to the GCV model through the shape comparison function. This shape-constrained energy can enhance the image constraint force by effectively connecting separate gaps of the object edge as well as driving the evolution contour to quickly approach the ideal object. Because of the slight movement of the AV in adjacent frames, the initial constraint shape is defined by users, with the other constraint shapes being derived from the segmentation results of adjacent sequence frames after morphological filtering. The AV is segmented from the US images by minimizing the proposed energy function. Results: To evaluate the performance of the proposed method, five assessment parameters were used to compare it with manual delineations performed by radiologists (gold standards). Three hundred and fifteen images acquired from nine groups were analyzed in the experiment. The area-metric overlap error rate was 6.89% ± 2.88%, the relative area difference rate 3.94% ± 2.63%, the average symmetric contour distance 1.08 ± 0.43 mm, the root mean square symmetric

  12. Surface coil imaging of the spine using fast sequences: Improvement of intensity profile and contrast behavior

    International Nuclear Information System (INIS)

    Requardt, H.; Deimling, M.; Weber, H.

    1986-01-01

    Sagittal and axial images obtained using a surface coil suffer from the extreme intensity profile caused by physical properties of the coil and the anatomic entity of subcutaneous fat. The authors present a measuring device that reduces these disadvantages by means of Helmholtz-type coils, and sequences that reduce the fat signal by dephasing its signal part. The extremely short repetition time (<30 msec) allows acquisition times shorter than 10 sec. Breath-holding for this short period to avoid movement artifacts is possible. Images are presented that illustrate the enhanced contrast of spinal tissue and surrounding structures. Comparisons are made with spin-echo and CHESS images

  13. Utility of gallium imaging in the diagnosis of Mycobacterium avium-intracellulare infection in patients with the acquired immunodeficiency syndrome

    International Nuclear Information System (INIS)

    Bach, M.C.; Bagwell, S.P.; Masur, H.

    1986-01-01

    Whole body Ga-67 scans revealed increased uptake in lymph nodes accessible for biopsy in three patients with the acquired immunodeficiency syndrome (AIDS) infected by Mycobacterium avium-intracellulare (MAI). In diagnostically difficult cases where the usual methods for diagnosing MAI are not helpful, Ga-67 studies may be of value

  14. TrueFisp versus HASTE sequences in 3T cine MRI: Evaluation of image quality during phonation in patients with velopharyngeal insufficiency

    International Nuclear Information System (INIS)

    Kulinna-Cosentini, Christiane; Czerny, Christian; Weber, Michael; Baumann, Arnulf; Sinko, Klaus

    2016-01-01

    To evaluate the image quality of two fast dynamic magnetic resonance imaging (MRI) sequences: True fast imaging with steady state precession (TrueFisp) was compared with half-Fourier acquired single turbo-spin-echo (HASTE) sequence for the characterization of velopharyngeal insufficiency (VPI) in repaired cleft palate patients. Twenty-two patients (10 female and 12 male; mean age, 17.7 ± 10.6 years; range, 9-31) with suspected VPI underwent 3-T MRI using TrueFisp and HASTE sequences. Imaging was performed in the sagittal plane at rest and during phonation of ''ee'' and ''k'' to assess the velum, tongue, posterior pharyngeal wall and a potential VP closure. The results were analysed independently by one radiologist and one orthodontist. HASTE performed better than TrueFisp for all evaluated items, except the tongue evaluation by the orthodontist during phonation of ''k'' and ''ee''. A statistically significant difference in favour of HASTE was observed in assessing the velum at rest and during phonation of ''k'' and ''ee'', and also in assessing VP closure in both raters (p < 0.05). TrueFisp imaging was twice as fast as HASTE (0.36 vs. 0.75 s/image). Dynamic HASTE images were of superior quality to those obtained with TrueFisp, although TrueFisp imaging was twice as fast. (orig.)

  15. Water imaging (hydrography) in the fetus: the value of a heavily T2-weighted sequence

    Energy Technology Data Exchange (ETDEWEB)

    Kline-Fath, Beth M.; Calvo-Garcia, Maria A.; O' Hara, Sara M.; Racadio, Judy M. [University of Cincinnati Medical Center, Department of Radiology, Cincinnati Children' s Hospital Medical Center, Cincinnati, OH (United States)

    2007-02-15

    Since the development of fast imaging sequences, MR has proved to be a helpful tool in the evaluation of fetal pathology. Because of the high water content of fetal tissues and pathology, hydrography imaging (MR fetography) can provide additional diagnostic information. To demonstrate the benefit of MR fetography in fetal imaging. From 2004 to 2005, 126 fetal MR examinations were performed for evaluation of an abnormality depicted on an antenatal sonogram. Single-shot fast spin-echo MR imaging and MR fetography were performed through the area of fetal pathology. The two studies were retrospectively compared. The primary diagnosis was not changed with the addition of MR fetography. New findings, particularly in the kidneys and spine, were identified in 9% of the patients. When fetal pathology was of high water content (80% patients), the MR fetography imaging increased diagnostic confidence. In 11% of the patients, those with cardiovascular or low water pathology, the MR fetography was not beneficial. The mainstay of fetal imaging is currently the HASTE and SSFSE sequences. However, MR fetography is an excellent adjunct that highlights fetal pathology by reinforcing the diagnosis, identifying additional findings, and providing high-contrast high-resolution images that are helpful when counseling clinicians and patients. (orig.)

  16. Common crus aplasia: diagnosis by 3D volume rendering imaging using 3DFT-CISS sequence

    International Nuclear Information System (INIS)

    Kim, H.J.; Song, J.W.; Chon, K.-M.; Goh, E.-K.

    2004-01-01

    AIM: The purpose of this study was to evaluate the findings of three-dimensional (3D) volume rendering (VR) imaging in common crus aplasia (CCA) of the inner ear. MATERIALS AND METHODS: Using 3D VR imaging of temporal bone constructive interference in steady state (CISS) magnetic resonance (MR) images, we retrospectively reviewed seven inner ears of six children who were candidates for cochlear implants and who had been diagnosed with CCA. As controls, we used the same method to examine 402 inner ears of 201 patients who had no clinical symptoms or signs of sensorineural hearing loss. Temporal bone MR imaging (MRI) was performed with a 1.5 T MR machine using a CISS sequence, and VR of the inner ear was performed on a work station. Morphological image analysis was performed on rotation views of 3D VR images. RESULTS: In all seven cases, CCA was diagnosed by the absence of the common crus. The remaining superior semicircular canal (SCC) was normal in five and hypoplastic in two inner ears, while the posterior SCC was normal in all seven. One patient showed bilateral symmetrical CCA. Complicated combined anomalies were seen in the cochlea, vestibule and lateral SCC. CONCLUSION: 3D VR imaging findings with MR CISS sequence can directly diagnose CCA. This technique may be useful in delineating detailed anomalies of SCCs

  17. Extracting a Good Quality Frontal Face Image from a Low-Resolution Video Sequence

    DEFF Research Database (Denmark)

    Nasrollahi, Kamal; Moeslund, Thomas B.

    2011-01-01

    Feeding low-resolution and low-quality images, from inexpensive surveillance cameras, to systems like, e.g., face recognition, produces erroneous and unstable results. Therefore, there is a need for a mechanism to bridge the gap between on one hand low-resolution and low-quality images......, we use a learning-based super-resolution algorithm applied to the result of the reconstruction-based part to improve the quality by another factor of two. This results in an improvement factor of four for the entire system. The proposed system has been tested on 122 low-resolution sequences from two...... different databases. The experimental results show that the proposed system can indeed produce a high-resolution and good quality frontal face image from low-resolution video sequences....

  18. Magnetic resonance imaging of anterior cruciate ligament of the knee: a comparison of four sequences

    International Nuclear Information System (INIS)

    Casillas, C.; Marti-Bonmati, L.; Molla, E.; Ferrer, P.; Dosda, R.

    1999-01-01

    To compare the diagnostic efficacy of the four magnetic resonance imaging (MRI) sequences that compose the standard protocol for the study of the knee in our center when employed in the examination of anterior cruciate ligament (ACL). A prospective study was carried out based on MRI findings in the knees of 326 consecutive patients. Sagittal [proton density (PD w eighted turbo-spin-echo and T2*-weighted gradient echo], coronal (PD-weighted turbo-spin-echo with fat suppression) and transverse (T2*-weighted gradient echo with magnetization transfer) images were evaluated. Each sequence was analyzed independently by two radiologists, while another two assessed all the sequences together with the clinical findings. Four categories were established: normal ACL, partially torn, completely torn and synovialized. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) with respect to the definitive diagnosis were calculated for each sequence. The statistical analysis of the findings for each category was done using the chi-squared test and the Kappa test was employed to assess the degree of agreement. According to the final diagnosis, 263 ACL were normal, 29 were partially torn, 33 were completely torn and there was 1 case of synovialization associated with a completely torn ACL. The relationship between the analysis of the ACL according to each sequence and the definitive diagnosis was very significant (p<0.001) and the agreement was excellent. All the sequences presented similar levels of diagnostic precision. The coronal sequence had least number of diagnostic errors (2.1%). The combinations of imaging techniques that resulted in the lowest error rate with respect to the definitive diagnosis were coronal PD-weighted turbo-spin-echo with fat suppression and sagittal PD-weighted turbo-spin-echo. Coronal images are highly precise in the evaluation of ACL. Sagittal sequences are the most valid for diagnosis of torn ACL. Transverse

  19. Pixel Color Clustering of Multi-Temporally Acquired Digital Photographs of a Rice Canopy by Luminosity-Normalization and Pseudo-Red-Green-Blue Color Imaging

    Directory of Open Access Journals (Sweden)

    Ryoichi Doi

    2014-01-01

    Full Text Available Red-green-blue (RGB channels of RGB digital photographs were loaded with luminosity-adjusted R, G, and completely white grayscale images, respectively (RGwhtB method, or R, G, and R + G (RGB yellow grayscale images, respectively (RGrgbyB method, to adjust the brightness of the entire area of multi-temporally acquired color digital photographs of a rice canopy. From the RGwhtB or RGrgbyB pseudocolor image, cyan, magenta, CMYK yellow, black, L*, a*, and b* grayscale images were prepared. Using these grayscale images and R, G, and RGB yellow grayscale images, the luminosity-adjusted pixels of the canopy photographs were statistically clustered. With the RGrgbyB and the RGwhtB methods, seven and five major color clusters were given, respectively. The RGrgbyB method showed clear differences among three rice growth stages, and the vegetative stage was further divided into two substages. The RGwhtB method could not clearly discriminate between the second vegetative and midseason stages. The relative advantages of the RGrgbyB method were attributed to the R, G, B, magenta, yellow, L*, and a* grayscale images that contained richer information to show the colorimetrical differences among objects than those of the RGwhtB method. The comparison of rice canopy colors at different time points was enabled by the pseudocolor imaging method.

  20. Whole-Genome Sequencing of a Human Clinical Isolate of emm28 Streptococcus pyogenes Causing Necrotizing Fasciitis Acquired Contemporaneously with Hurricane Harvey

    OpenAIRE

    Long, S. Wesley; Kachroo, Priyanka; Musser, James M.; Olsen, Randall J.

    2017-01-01

    ABSTRACT We discovered an emm28 Streptococcus pyogenes isolate causing necrotizing fasciitis in a patient exposed to the floodwaters of Hurricane Harvey in the Houston, TX, metropolitan area in August 2017. The Oxford Nanopore MinION instrument provided sufficient genome sequence data within 1 h of beginning sequencing to close the genome.

  1. SIFT-based dense pixel tracking on 0.35 T cine-MR images acquired during image-guided radiation therapy with application to gating optimization

    Energy Technology Data Exchange (ETDEWEB)

    Mazur, Thomas R., E-mail: tmazur@radonc.wustl.edu, E-mail: hli@radonc.wustl.edu; Fischer-Valuck, Benjamin W.; Wang, Yuhe; Yang, Deshan; Mutic, Sasa; Li, H. Harold, E-mail: tmazur@radonc.wustl.edu, E-mail: hli@radonc.wustl.edu [Department of Radiation Oncology, Washington University School of Medicine, 4921 Parkview Place, Campus Box 8224, St. Louis, Missouri 63110 (United States)

    2016-01-15

    Purpose: To first demonstrate the viability of applying an image processing technique for tracking regions on low-contrast cine-MR images acquired during image-guided radiation therapy, and then outline a scheme that uses tracking data for optimizing gating results in a patient-specific manner. Methods: A first-generation MR-IGRT system—treating patients since January 2014—integrates a 0.35 T MR scanner into an annular gantry consisting of three independent Co-60 sources. Obtaining adequate frame rates for capturing relevant patient motion across large fields-of-view currently requires coarse in-plane spatial resolution. This study initially (1) investigate the feasibility of rapidly tracking dense pixel correspondences across single, sagittal plane images (with both moderate signal-to-noise and spatial resolution) using a matching objective for highly descriptive vectors called scale-invariant feature transform (SIFT) descriptors associated to all pixels that describe intensity gradients in local regions around each pixel. To more accurately track features, (2) harmonic analysis was then applied to all pixel trajectories within a region-of-interest across a short training period. In particular, the procedure adjusts the motion of outlying trajectories whose relative spectral power within a frequency bandwidth consistent with respiration (or another form of periodic motion) does not exceed a threshold value that is manually specified following the training period. To evaluate the tracking reliability after applying this correction, conventional metrics—including Dice similarity coefficients (DSCs), mean tracking errors (MTEs), and Hausdorff distances (HD)—were used to compare target segmentations obtained via tracking to manually delineated segmentations. Upon confirming the viability of this descriptor-based procedure for reliably tracking features, the study (3) outlines a scheme for optimizing gating parameters—including relative target position and a

  2. A moving blocker-based strategy for simultaneous megavoltage and kilovoltage scatter correction in cone-beam computed tomography image acquired during volumetric modulated arc therapy

    International Nuclear Information System (INIS)

    Ouyang, Luo; Lee, Huichen Pam; Wang, Jing

    2015-01-01

    Purpose: To evaluate a moving blocker-based approach in estimating and correcting megavoltage (MV) and kilovoltage (kV) scatter contamination in kV cone-beam computed tomography (CBCT) acquired during volumetric modulated arc therapy (VMAT). Methods and materials: During the concurrent CBCT/VMAT acquisition, a physical attenuator (i.e., “blocker”) consisting of equally spaced lead strips was mounted and moved constantly between the CBCT source and patient. Both kV and MV scatter signals were estimated from the blocked region of the imaging panel, and interpolated into the unblocked region. A scatter corrected CBCT was then reconstructed from the unblocked projections after scatter subtraction using an iterative image reconstruction algorithm based on constraint optimization. Experimental studies were performed on a Catphan® phantom and an anthropomorphic pelvis phantom to demonstrate the feasibility of using a moving blocker for kV–MV scatter correction. Results: Scatter induced cupping artifacts were substantially reduced in the moving blocker corrected CBCT images. Quantitatively, the root mean square error of Hounsfield units (HU) in seven density inserts of the Catphan phantom was reduced from 395 to 40. Conclusions: The proposed moving blocker strategy greatly improves the image quality of CBCT acquired with concurrent VMAT by reducing the kV–MV scatter induced HU inaccuracy and cupping artifacts

  3. Acquired Methemoglobinaemia

    Directory of Open Access Journals (Sweden)

    Adil Al-Lawati

    2012-05-01

    Full Text Available Acquired methemoglobinaemia is a relatively rare condition and, therefore infrequently encountered in acute medical practice. Suspicion of the condition may be triggered when the measured PaO2 is ‘out of keeping’ with the oxygen saturations that are discovered with pulse oximetry. We describe two separate cases of acquired methemoglobinaemia secondary to the recreational use of alkyl nitrites (’poppers’. The patients presented at separate times to two different teaching hospitals in London, UK. The similarity of these cases has led the authors to conclude that a raised awareness of this potentially fatal condition, and its association with a widely-available recreational drug, is necessary to ensure a correct and timely diagnosis.

  4. New Algorithm to Enable Construction and Display of 3D Structures from Scanning Probe Microscopy Images Acquired Layer-by-Layer.

    Science.gov (United States)

    Deng, William Nanqiao; Wang, Shuo; Ventrici de Souza, Joao Francisco; Kuhl, Tonya L; Liu, Gang-Yu

    2018-06-11

    Scanning probe microscopy (SPM) such as atomic force microscopy (AFM) is widely known for high-resolution imaging of surface structures and nanolithography in two dimension (2D), which provides important physical insights in surface science and material science. This work reports a new algorithm to enable construction and display of layer-by-layer 3D structures from SPM images. The algorithm enables alignment of SPM images acquired during layer-by-layer deposition, removal of redundant features, and faithfully constructs the deposited 3D structures. The display uses a "see-through" strategy to enable the structure of each layer to be visible. The results demonstrate high spatial accuracy as well as algorithm versatility; users can set parameters for reconstruction and display as per image quality and research needs. To the best of our knowledge, this method represents the first report to enable SPM technology for 3D imaging construction and display. The detailed algorithm is provided to facilitate usage of the same approach in any SPM software. These new capabilities support wide applications of SPM that require 3D image reconstruction and display, such as 3D nanoprinting, and 3D additive and subtractive manufacturing and imaging.

  5. Magnetic nanoparticle imaging by random and maximum length sequences of inhomogeneous activation fields.

    Science.gov (United States)

    Baumgarten, Daniel; Eichardt, Roland; Crevecoeur, Guillaume; Supriyanto, Eko; Haueisen, Jens

    2013-01-01

    Biomedical applications of magnetic nanoparticles require a precise knowledge of their biodistribution. From multi-channel magnetorelaxometry measurements, this distribution can be determined by means of inverse methods. It was recently shown that the combination of sequential inhomogeneous excitation fields in these measurements is favorable regarding the reconstruction accuracy when compared to homogeneous activation . In this paper, approaches for the determination of activation sequences for these measurements are investigated. Therefor, consecutive activation of single coils, random activation patterns and families of m-sequences are examined in computer simulations involving a sample measurement setup and compared with respect to the relative condition number of the system matrix. We obtain that the values of this condition number decrease with larger number of measurement samples for all approaches. Random sequences and m-sequences reveal similar results with a significant reduction of the required number of samples. We conclude that the application of pseudo-random sequences for sequential activation in the magnetorelaxometry imaging of magnetic nanoparticles considerably reduces the number of required sequences while preserving the relevant measurement information.

  6. Correction of projective distortion in long-image-sequence mosaics without prior information

    Science.gov (United States)

    Yang, Chenhui; Mao, Hongwei; Abousleman, Glen; Si, Jennie

    2010-04-01

    Image mosaicking is the process of piecing together multiple video frames or still images from a moving camera to form a wide-area or panoramic view of the scene being imaged. Mosaics have widespread applications in many areas such as security surveillance, remote sensing, geographical exploration, agricultural field surveillance, virtual reality, digital video, and medical image analysis, among others. When mosaicking a large number of still images or video frames, the quality of the resulting mosaic is compromised by projective distortion. That is, during the mosaicking process, the image frames that are transformed and pasted to the mosaic become significantly scaled down and appear out of proportion with respect to the mosaic. As more frames continue to be transformed, important target information in the frames can be lost since the transformed frames become too small, which eventually leads to the inability to continue further. Some projective distortion correction techniques make use of prior information such as GPS information embedded within the image, or camera internal and external parameters. Alternatively, this paper proposes a new algorithm to reduce the projective distortion without using any prior information whatsoever. Based on the analysis of the projective distortion, we approximate the projective matrix that describes the transformation between image frames using an affine model. Using singular value decomposition, we can deduce the affine model scaling factor that is usually very close to 1. By resetting the image scale of the affine model to 1, the transformed image size remains unchanged. Even though the proposed correction introduces some error in the image matching, this error is typically acceptable and more importantly, the final mosaic preserves the original image size after transformation. We demonstrate the effectiveness of this new correction algorithm on two real-world unmanned air vehicle (UAV) sequences. The proposed method is

  7. Effects of imaging gradients in sequences with varying longitudinal storage time-Case of diffusion exchange imaging.

    Science.gov (United States)

    Lasič, Samo; Lundell, Henrik; Topgaard, Daniel; Dyrby, Tim B

    2018-04-01

    To illustrate the potential bias caused by imaging gradients in correlation MRI sequences using longitudinal magnetization storage (LS) and examine the case of filter exchange imaging (FEXI) yielding maps of the apparent exchange rate (AXR). The effects of imaging gradients in FEXI were observed on yeast cells. To analyze the AXR bias, signal evolution was calculated by applying matrix exponential operators. A sharp threshold for the slice thickness was identified, below which the AXR is increasingly underestimated. The bias can be understood in terms of an extended low-pass diffusion filtering during the LS interval, which is more pronounced at lower exchange rates. For a total exchange rate constant larger than 1 s -1 , the AXR bias is expected to be negligible when slices thicker than 2.5 mm are used. In correlation experiments like FEXI, relying on LS with variable duration, imaging gradients may cause disrupting effects that cannot be easily mitigated and should be carefully considered for unbiased results. In typical clinical applications of FEXI, the imaging gradients are expected to cause a negligible AXR bias. However, the AXR bias may be significant in preclinical settings or whenever thin imaging slices are used. Magn Reson Med 79:2228-2235, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  8. Automatic registration of panoramic image sequence and mobile laser scanning data using semantic features

    Science.gov (United States)

    Li, Jianping; Yang, Bisheng; Chen, Chi; Huang, Ronggang; Dong, Zhen; Xiao, Wen

    2018-02-01

    Inaccurate exterior orientation parameters (EoPs) between sensors obtained by pre-calibration leads to failure of registration between panoramic image sequence and mobile laser scanning data. To address this challenge, this paper proposes an automatic registration method based on semantic features extracted from panoramic images and point clouds. Firstly, accurate rotation parameters between the panoramic camera and the laser scanner are estimated using GPS and IMU aided structure from motion (SfM). The initial EoPs of panoramic images are obtained at the same time. Secondly, vehicles in panoramic images are extracted by the Faster-RCNN as candidate primitives to be matched with potential corresponding primitives in point clouds according to the initial EoPs. Finally, translation between the panoramic camera and the laser scanner is refined by maximizing the overlapping area of corresponding primitive pairs based on the Particle Swarm Optimization (PSO), resulting in a finer registration between panoramic image sequences and point clouds. Two challenging urban scenes were experimented to assess the proposed method, and the final registration errors of these two scenes were both less than three pixels, which demonstrates a high level of automation, robustness and accuracy.

  9. Object-Oriented Query Language For Events Detection From Images Sequences

    Science.gov (United States)

    Ganea, Ion Eugen

    2015-09-01

    In this paper is presented a method to represent the events extracted from images sequences and the query language used for events detection. Using an object oriented model the spatial and temporal relationships between salient objects and also between events are stored and queried. This works aims to unify the storing and querying phases for video events processing. The object oriented language syntax used for events processing allow the instantiation of the indexes classes in order to improve the accuracy of the query results. The experiments were performed on images sequences provided from sport domain and it shows the reliability and the robustness of the proposed language. To extend the language will be added a specific syntax for constructing the templates for abnormal events and for detection of the incidents as the final goal of the research.

  10. Minimization of Dead-Periods in MRI Pulse Sequences for Imaging Oblique Planes

    Science.gov (United States)

    Atalar, Ergin; McVeigh, Elliot R.

    2007-01-01

    With the advent of breath-hold MR cardiac imaging techniques, the minimization of TR and TE for oblique planes has become a critical issue. The slew rates and maximum currents of gradient amplifiers limit the minimum possible TR and TE by adding dead-periods to the pulse sequences. We propose a method of designing gradient waveforms that will be applied to the amplifiers instead of the slice, readout, and phase encoding waveforms. Because this method ensures that the gradient amplifiers will always switch at their maximum slew rate, it results in the minimum possible dead-period for given imaging parameters and scan plane position. A GRASS pulse sequence has been designed and ultra-short TR and TE values have been obtained with standard gradient amplifiers and coils. For some oblique slices, we have achieved shorter TR and TE values than those for nonoblique slices. PMID:7869900

  11. [Study on method of tracking the active cells in image sequences based on EKF-PF].

    Science.gov (United States)

    Tang, Chunming; Liu, Ying

    2013-02-01

    In cell image sequences, due to the nonlinear and nonGaussian motion characteristics of active cells, the accurate prediction and tracking is still an unsolved problem. We applied extended Kalman particle filter (EKF-PF) here in our study, attempting to solve the problem. Firstly we confirmed the existence and positions of the active cells. Then we established a motion model and improved it via adding motion angle estimation. Next we predicted motion parameters, such as displacement, velocity, accelerated velocity and motion angle, in region centers of the cells being tracked. Finally we obtained the motion traces of active cells. There were fourteen active cells in three image sequences which have been tracked. The errors were less than 2.5 pixels when the prediction values were compared with actual values. It showed that the presented algorithm may basically reach the solution of accurate predition and tracking of the active cells.

  12. Visualization and correction of automated segmentation, tracking and lineaging from 5-D stem cell image sequences.

    Science.gov (United States)

    Wait, Eric; Winter, Mark; Bjornsson, Chris; Kokovay, Erzsebet; Wang, Yue; Goderie, Susan; Temple, Sally; Cohen, Andrew R

    2014-10-03

    Neural stem cells are motile and proliferative cells that undergo mitosis, dividing to produce daughter cells and ultimately generating differentiated neurons and glia. Understanding the mechanisms controlling neural stem cell proliferation and differentiation will play a key role in the emerging fields of regenerative medicine and cancer therapeutics. Stem cell studies in vitro from 2-D image data are well established. Visualizing and analyzing large three dimensional images of intact tissue is a challenging task. It becomes more difficult as the dimensionality of the image data increases to include time and additional fluorescence channels. There is a pressing need for 5-D image analysis and visualization tools to study cellular dynamics in the intact niche and to quantify the role that environmental factors play in determining cell fate. We present an application that integrates visualization and quantitative analysis of 5-D (x,y,z,t,channel) and large montage confocal fluorescence microscopy images. The image sequences show stem cells together with blood vessels, enabling quantification of the dynamic behaviors of stem cells in relation to their vascular niche, with applications in developmental and cancer biology. Our application automatically segments, tracks, and lineages the image sequence data and then allows the user to view and edit the results of automated algorithms in a stereoscopic 3-D window while simultaneously viewing the stem cell lineage tree in a 2-D window. Using the GPU to store and render the image sequence data enables a hybrid computational approach. An inference-based approach utilizing user-provided edits to automatically correct related mistakes executes interactively on the system CPU while the GPU handles 3-D visualization tasks. By exploiting commodity computer gaming hardware, we have developed an application that can be run in the laboratory to facilitate rapid iteration through biological experiments. We combine unsupervised image

  13. The value of MR imaging of PDFASAT sequence in the diagnosis of extremities occult fractures

    International Nuclear Information System (INIS)

    Lu Lingquan; Xu Mingshen; Wu Qianzhi; Mao Chunnan; Wang Shuzi; Zhou Xingfan; Wang Liping

    2004-01-01

    Objective: To investigate the value of MR imaging of proton density weighted-fat saturated (PDFASAT) sequence in detecting the occult fracture of extremities. Methods: Thirty-one patients with acute trauma were studied using radiography and MR imaging within 45 days. MR sequences included FSE T 1 WI, T 2 WI, and PDFASAT. 21 occult fractures occurred in the knee joint, 6 in the hip joint, 1 in the elbow joint, 2 in the shoulder, and 1 in the ankle. Results: All 31 cases had normal radiographic results. 10 cases with proximal fibula, 4 with proximal tibia and 7 with femur condyle occult fractures were found in 21 knee joint acute trauma cases. 2 cases with intertrochanteric, 2 with femoral neck and 2 with cotyle occult fractures were found in 6 hip joint trauma cases. 2 proximal humerus occult fractures were found in 2 shoulder cases. 1 distal humerus and 1 distal fibula occult fracture was found in elbow and ankle cases. MR imaging demonstrated irregular linear low signal in the subcortical region on both T 1 WI and T 2 WI, and high signal changes around low signal were seen on T 2 WI in some cases. The high signal in PDFASAT sequence was more remarkable and wider than that on both T 1 WI and T 2 WI. Conclusion: MR imaging could determine the diagnosis of acute and chronic occult fractures. MRI should be the next choice when plain films fail to reveal suspected fractures in setting of suggestive symptoms and positive physical examination. PDFASAT would be the best effective sequence among the T 1 WI, T 2 WI, and PDFASAT. (author)

  14. Fast triple-spin-echo Dixon (FTSED) sequence for water and fat imaging

    Czech Academy of Sciences Publication Activity Database

    Kořínek, Radim; Bartušek, Karel; Starčuk jr., Zenon

    2017-01-01

    Roč. 37, APR (2017), s. 164-170 ISSN 0730-725X R&D Projects: GA MŠk ED0017/01/01; GA MŠk(CZ) LO1212 Institutional support: RVO:68081731 Keywords : fast triple-spin-echo Dixon * sequence * MRI * fat fraction * water-fat * ultra-high field * 9.4 T * FTSED Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Radiology, nuclear medicine and medical imaging Impact factor: 2.225, year: 2016

  15. X-ray image processing software for computing object size and object location coordinates from acquired optical and x-ray images

    International Nuclear Information System (INIS)

    Tiwari, Akash; Tiwari, Shyam Sunder; Tiwari, Railesha; Panday, Lokesh; Panday, Jeet; Suri, Nitin

    2004-01-01

    X-ray and Visible image data processing software has been developed in Visual Basic for real time online and offline image information processing for NDT and Medical Applications. Software computes two dimension image size parameters from its sharp boundary lines by raster scanning the image contrast data. Code accepts bit map image data and hunts for multiple tumors of different sizes that may be present in the image definition and then computes size of each tumor and locates its approximate center for registering its location coordinates. Presence of foreign metal and glass balls industrial product such as chocolate and other food items imaged out using x-ray imaging technique are detected by the software and their size and position co-ordinates are computed by the software. Paper discusses ways and means to compute size and coordinated of air bubble like objects present in the x-ray and optical images and their multiple existences in image of interest. (author)

  16. Spatio-temporal Hotelling observer for signal detection from image sequences.

    Science.gov (United States)

    Caucci, Luca; Barrett, Harrison H; Rodriguez, Jeffrey J

    2009-06-22

    Detection of signals in noisy images is necessary in many applications, including astronomy and medical imaging. The optimal linear observer for performing a detection task, called the Hotelling observer in the medical literature, can be regarded as a generalization of the familiar prewhitening matched filter. Performance on the detection task is limited by randomness in the image data, which stems from randomness in the object, randomness in the imaging system, and randomness in the detector outputs due to photon and readout noise, and the Hotelling observer accounts for all of these effects in an optimal way. If multiple temporal frames of images are acquired, the resulting data set is a spatio-temporal random process, and the Hotelling observer becomes a spatio-temporal linear operator. This paper discusses the theory of the spatio-temporal Hotelling observer and estimation of the required spatio-temporal covariance matrices. It also presents a parallel implementation of the observer on a cluster of Sony PLAYSTATION 3 gaming consoles. As an example, we consider the use of the spatio-temporal Hotelling observer for exoplanet detection.

  17. On the Farey sequence and its augmentation for applications to image analysis

    Directory of Open Access Journals (Sweden)

    Pratihar Sanjoy

    2017-09-01

    Full Text Available We introduce a novel concept of the augmented Farey table (AFT. Its purpose is to store the ranks of fractions of a Farey sequence in an efficient manner so as to return the rank of any query fraction in constant time. As a result, computations on the digital plane can be crafted down to simple integer operations; for example, the tasks like determining the extent of collinearity of integer points or of parallelism of straight lines—often required to solve many image-analytic problems—can be made fast and efficient through an appropriate AFT-based tool. We derive certain interesting characterizations of an AFT for its efficient generation. We also show how, for a fraction not present in a Farey sequence, the rank of the nearest fraction in that sequence can efficiently be obtained by the regula falsi method from the AFT concerned. To assert its merit, we show its use in two applications—one in polygonal approximation of digital curves and the other in skew correction of engineering drawings in document images. Experimental results indicate the potential of the AFT in such image-analytic applications.

  18. Assessment of Myocardial Fibrosis in Mice Using a T2*-Weighted 3D Radial Magnetic Resonance Imaging Sequence.

    Directory of Open Access Journals (Sweden)

    Bastiaan J van Nierop

    Full Text Available Myocardial fibrosis is a common hallmark of many diseases of the heart. Late gadolinium enhanced MRI is a powerful tool to image replacement fibrosis after myocardial infarction (MI. Interstitial fibrosis can be assessed indirectly from an extracellular volume fraction measurement using contrast-enhanced T1 mapping. Detection of short T2* species resulting from fibrotic tissue may provide an attractive non-contrast-enhanced alternative to directly visualize the presence of both replacement and interstitial fibrosis.To goal of this paper was to explore the use of a T2*-weighted radial sequence for the visualization of fibrosis in mouse heart.C57BL/6 mice were studied with MI (n = 20, replacement fibrosis, transverse aortic constriction (TAC (n = 18, diffuse fibrosis, and as control (n = 10. 3D center-out radial T2*-weighted images with varying TE were acquired in vivo and ex vivo (TE = 21 μs-4 ms. Ex vivo T2*-weighted signal decay with TE was analyzed using a 3-component model. Subtraction of short- and long-TE images was used to highlight fibrotic tissue with short T2*. The presence of fibrosis was validated using histology and correlated to MRI findings.Detailed ex vivo T2*-weighted signal analysis revealed a fast (T2*fast, slow (T2*slow and lipid (T2*lipid pool. T2*fast remained essentially constant. Infarct T2*slow decreased significantly, while a moderate decrease was observed in remote tissue in post-MI hearts and in TAC hearts. T2*slow correlated with the presence of diffuse fibrosis in TAC hearts (r = 0.82, P = 0.01. Ex vivo and in vivo subtraction images depicted a positive contrast in the infarct co-localizing with the scar. Infarct volumes from histology and subtraction images linearly correlated (r = 0.94, P<0.001. Region-of-interest analysis in the in vivo post-MI and TAC hearts revealed significant T2* shortening due to fibrosis, in agreement with the ex vivo results. However, in vivo contrast on subtraction images was rather poor

  19. Optimal MR pulse sequences for hepatic hemangiomas : comparison of T2-weighted turbo-spin-echo, T2-weighted breath-hold turbo-spin-echo, and T1-weighted FLASH dynamic imaging

    International Nuclear Information System (INIS)

    Wang, Wen Chao; Choi, Byung Ihn; Han, Joon Koo; Kim, Tae Kyoung; Cho, Soon Gu

    1997-01-01

    To optimize MR imaging pulse sequences in the imaging of hepatic hemangioma and to evaluate on dynamic MR imaging the enhancing characteristics of the lesions. Twenty patients with 35 hemangiomas were studied by using Turbo-spin-echo (TSE) sequence (T2-weighted, T2- and heavily T2-weighted breath-hold) and T1-weighted FLASH imaging acquired before, immediately on, and 1, 3 and 5 minutes after injection of a bolus of Gd-DTPA (0.1mmol/kg). Phased-array multicoil was employed. Images were quantitatively analyzed for lesion-to-liver signal difference to noise ratios (SD/Ns), and lesion-to-liver signal ratios (H/Ls), and qualitatively analyzed for lesion conspicuity. The enhancing characteristics of the hemangiomas were described by measuring the change of signal intensity as a curve in T1-weighted FLASH dynamic imaging. For T2-weighted images, breath-hold T2-weighted TSE had a slightly higher SD/N than other pulse sequences, but there was no statistical difference in three fast pulse sequences (p=0.211). For lesion conspicuity, heavily T2-weighted breath-hold TSE images was superior to T2-weighted breath-hold or non-breath-hold TSE (H/L, 5.75, 3.81, 2.87, respectively, p<0.05). T2-weighted breath-hold TSE imaging was more effective than T2-weighted TSE imaging in removing lesion blurring or lack of sharpness, and there was a 12-fold decrease in acquisition time (20sec versus 245 sec). T1-weighted FLASH dynamic images of normal liver showed peak enhancement at less than 1 minute, and of hemangioma at more than 3 minutes;the degree of enhancement for hemangioma decreased after a 3 minute delay. T2-weighed breath-hold TSE imaging and Gd-DTPA enhanced FLASH dynamic imaging with 5 minutes delay are sufficient for imaging hepatic hemangiomas

  20. Applicability of the 3D-VIBE sequence to whole brain imaging

    International Nuclear Information System (INIS)

    Makabe, Takeshi; Nakamura, Manami; Moriyama, Ryo

    2009-01-01

    The volumetric interpolated breath-hold examination (VIBE) method has been developed imaging also holds its breath in an abdomen, and to do three-dimensional T1WI in possible time in gradient echo sequence, and applied to dynamic study mainly and planning for time reduction using an interpolation and partial fourier. We considered the condition for imaging to do whole brain as high resolution image using VIBE. Even if base matrix was maintained when an interpolation and partial fourier were used too much excessively by Phantom experiment, the resolution of multiplanar reconstruction (MPR) image fell. There was a limit of the interpolation therefore to maintain the resolution as voxel. Signal-to-noise ratio (SNR) fell by flip angle (FA) increase by the applicability to the head, and peak existed in about 15 deg in contrast-to-noise ratio (CNR) of white matter and gray matter. Therefore by it's clinical and optimizing the imaging condition of VIBE, whole brain, it was imaging possible in about 3 minutes as high resolution image. (author)

  1. Noninvasive imaging of three-dimensional cardiac activation sequence during pacing and ventricular tachycardia.

    Science.gov (United States)

    Han, Chengzong; Pogwizd, Steven M; Killingsworth, Cheryl R; He, Bin

    2011-08-01

    Imaging cardiac excitation within ventricular myocardium is important in the treatment of cardiac arrhythmias and might help improve our understanding of arrhythmia mechanisms. This study sought to rigorously assess the imaging performance of a 3-dimensional (3D) cardiac electrical imaging (3DCEI) technique with the aid of 3D intracardiac mapping from up to 216 intramural sites during paced rhythm and norepinephrine (NE)-induced ventricular tachycardia (VT) in the rabbit heart. Body surface potentials and intramural bipolar electrical recordings were simultaneously measured in a closed-chest condition in 13 healthy rabbits. Single-site pacing and dual-site pacing were performed from ventricular walls and septum. VTs and premature ventricular complexes (PVCs) were induced by intravenous NE. Computed tomography images were obtained to construct geometry models. The noninvasively imaged activation sequence correlated well with invasively measured counterpart, with a correlation coefficient of 0.72 ± 0.04, and a relative error of 0.30 ± 0.02 averaged over 520 paced beats as well as 73 NE-induced PVCs and VT beats. All PVCs and VT beats initiated in the subendocardium by a nonreentrant mechanism. The averaged distance from the imaged site of initial activation to the pacing site or site of arrhythmias determined from intracardiac mapping was ∼5 mm. For dual-site pacing, the double origins were identified when they were located at contralateral sides of ventricles or at the lateral wall and the apex. 3DCEI can noninvasively delineate important features of focal or multifocal ventricular excitation. It offers the potential to aid in localizing the origins and imaging activation sequences of ventricular arrhythmias, and to provide noninvasive assessment of the underlying arrhythmia mechanisms. Copyright © 2011 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  2. Normalization of white matter intensity on T1-weighted images of patients with acquired central nervous system demyelination.

    Science.gov (United States)

    Ghassemi, Rezwan; Brown, Robert; Narayanan, Sridar; Banwell, Brenda; Nakamura, Kunio; Arnold, Douglas L

    2015-01-01

    Intensity variation between magnetic resonance images (MRI) hinders comparison of tissue intensity distributions in multicenter MRI studies of brain diseases. The available intensity normalization techniques generally work well in healthy subjects but not in the presence of pathologies that affect tissue intensity. One such disease is multiple sclerosis (MS), which is associated with lesions that prominently affect white matter (WM). To develop a T1-weighted (T1w) image intensity normalization method that is independent of WM intensity, and to quantitatively evaluate its performance. We calculated median intensity of grey matter and intraconal orbital fat on T1w images. Using these two reference tissue intensities we calculated a linear normalization function and applied this to the T1w images to produce normalized T1w (NT1) images. We assessed performance of our normalization method for interscanner, interprotocol, and longitudinal normalization variability, and calculated the utility of the normalization method for lesion analyses in clinical trials. Statistical modeling showed marked decreases in T1w intensity differences after normalization (P < .0001). We developed a WM-independent T1w MRI normalization method and tested its performance. This method is suitable for longitudinal multicenter clinical studies for the assessment of the recovery or progression of disease affecting WM. Copyright © 2014 by the American Society of Neuroimaging.

  3. The impact of the CartoSound® image directly acquired from the left atrium for integration in atrial fibrillation ablation.

    Science.gov (United States)

    Kaseno, Kenichi; Hisazaki, Kaori; Nakamura, Kohki; Ikeda, Etsuko; Hasegawa, Kanae; Aoyama, Daisetsu; Shiomi, Yuichiro; Ikeda, Hiroyuki; Morishita, Tetsuji; Ishida, Kentaro; Amaya, Naoki; Uzui, Hiroyasu; Tada, Hiroshi

    2018-04-14

    Intracardiac echocardiographic (ICE) imaging might be useful for integrating three-dimensional computed tomographic (CT) images for left atrial (LA) catheter navigation during atrial fibrillation (AF) ablation. However, the optimal CT image integration method using ICE has not been established. This study included 52 AF patients who underwent successful circumferential pulmonary vein isolation (CPVI). In all patients, CT image integration was performed after the CPVI with the following two methods: (1) using ICE images of the LA derived from the right atrium and right ventricular outflow tract (RA-merge) and (2) using ICE images of the LA directly derived from the LA added to the image for the RA-merge (LA-merge). The accuracy of these two methods was assessed by the distances between the integrated CT image and ICE image (ICE-to-CT distance), and between the CT image and actual ablated sites for the CPVI (CT-to-ABL distance). The mean ICE-to-CT distance was comparable between the two methods (RA-merge = 1.6 ± 0.5 mm, LA-merge = 1.7 ± 0.4 mm; p = 0.33). However, the mean CT-to-ABL distance was shorter for the LA-merge (2.1 ± 0.6 mm) than RA-merge (2.5 ± 0.8 mm; p imaging, and whereas the greatest CT-to-ABL distance was observed at the roof portion of the left superior PV (3.7 ± 2.8 mm) after the RA-merge, it improved to 2.6 ± 1.9 mm after the LA-merge (p images of the LA directly acquired from the LA might lead to a greater accuracy of the CT image integration for the CVPI.

  4. Characterization of platelet adhesion under flow using microscopic image sequence analysis.

    Science.gov (United States)

    Machin, M; Santomaso, A; Cozzi, M R; Battiston, M; Mazzuccato, M; De Marco, L; Canu, P

    2005-07-01

    A method for quantitative analysis of platelet deposition under flow is discussed here. The model system is based upon perfusion of blood platelets over an adhesive substrate immobilized on a glass coverslip acting as the lower surface of a rectangular flow chamber. The perfusion apparatus is mounted onto an inverted microscope equipped with epifluorescent illumination and intensified CCD video camera. Characterization is based on information obtained from a specific image analysis method applied to continuous sequences of microscopical images. Platelet recognition across the sequence of images is based on a time-dependent, bidimensional, gaussian-like pdf. Once a platelet is located,the variation of its position and shape as a function of time (i.e., the platelet history) can be determined. Analyzing the history we can establish if the platelet is moving on the surface, the frequency of this movement and the distance traveled before its resumes the velocity of a non-interacting cell. Therefore, we can determine how long the adhesion would last which is correlated to the resistance of the platelet-substrate bond. This algorithm enables the dynamic quantification of trajectories, as well as residence times, arrest and release frequencies for a high numbers of platelets at the same time. Statistically significant conclusions on platelet-surface interactions can then be obtained. An image analysis tool of this kind can dramatically help the investigation and characterization of the thrombogenic properties of artificial surfaces such as those used in artificial organs and biomedical devices.

  5. Prediction of cervical cancer recurrence using textural features extracted from 18F-FDG PET images acquired with different scanners.

    Science.gov (United States)

    Reuzé, Sylvain; Orlhac, Fanny; Chargari, Cyrus; Nioche, Christophe; Limkin, Elaine; Riet, François; Escande, Alexandre; Haie-Meder, Christine; Dercle, Laurent; Gouy, Sébastien; Buvat, Irène; Deutsch, Eric; Robert, Charlotte

    2017-06-27

    To identify an imaging signature predicting local recurrence for locally advanced cervical cancer (LACC) treated by chemoradiation and brachytherapy from baseline 18F-FDG PET images, and to evaluate the possibility of gathering images from two different PET scanners in a radiomic study. 118 patients were included retrospectively. Two groups (G1, G2) were defined according to the PET scanner used for image acquisition. Eleven radiomic features were extracted from delineated cervical tumors to evaluate: (i) the predictive value of features for local recurrence of LACC, (ii) their reproducibility as a function of the scanner within a hepatic reference volume, (iii) the impact of voxel size on feature values. Eight features were statistically significant predictors of local recurrence in G1 (p features were significantly different between G1 and G2 in the liver. Spatial resampling was not sufficient to explain the stratification effect. This study showed that radiomic features could predict local recurrence of LACC better than SUVmax. Further investigation is needed before applying a model designed using data from one PET scanner to another.

  6. Magnetic resonance imaging of intraoral hard and soft tissues using an intraoral coil and FLASH sequences

    Energy Technology Data Exchange (ETDEWEB)

    Fluegge, Tabea; Eisenbeiss, Anne-Kathrin; Schmelzeisen, Rainer; Nelson, Katja [University Medical Center Freiburg, Department of Oral and Maxillofacial Surgery, Freiburg (Germany); Hoevener, Jan-Bernd; Ludwig, Ute; Hennig, Juergen [University Medical Center Freiburg, Medical Physics, Department of Radiology, Freiburg (Germany); Spittau, Bjoern [Albert Ludwig University of Freiburg, Institute of Anatomy and Cell Biology, Freiburg (Germany)

    2016-12-15

    To ascertain the feasibility of MRI as a non-ionizing protocol for routine dentomaxillofacial diagnostic imaging. Wireless coils were used for MRI of intraoral hard and soft tissues. FLASH MRI was applied in vivo with a mandible voxel size of 250 x 250 x 500 μm{sup 3}, FOV of 64 x 64 x 28 mm{sup 3} and acquisition time of 3:57 min and with a maxilla voxel size of 350 μm{sup 3} and FOV of 34 cm{sup 3} in 6:40 min. Ex vivo imaging was performed in 4:38 min, with a resolution of 200 μm{sup 3} and FOV of 36.5 cm{sup 3}. Cone beam (CB) CT of the mandible and subjects were acquired. MRI was compared to CBCT and histological sections. Deviations were calculated with intraclass correlation coefficient (ICC) and coefficient of variation (c{sub v}). A high congruence between CBCT, MRI and specimens was demonstrated. Hard and soft tissues including dental pulp, periodontium, gingiva, cancellous bone and mandibular canal contents were adequately displayed with MRI. Imaging of select intraoral tissues was achieved using custom MRI protocols with an easily applicable intraoral coil in a clinically acceptable acquisition time. Comparison with CBCT and histological sections helped demonstrate dimensional accuracy of the MR images. The course of the mandibular canal was accurately displayed with CBCT and MRI. (orig.)

  7. Magnetic resonance imaging of intraoral hard and soft tissues using an intraoral coil and FLASH sequences

    International Nuclear Information System (INIS)

    Fluegge, Tabea; Eisenbeiss, Anne-Kathrin; Schmelzeisen, Rainer; Nelson, Katja; Hoevener, Jan-Bernd; Ludwig, Ute; Hennig, Juergen; Spittau, Bjoern

    2016-01-01

    To ascertain the feasibility of MRI as a non-ionizing protocol for routine dentomaxillofacial diagnostic imaging. Wireless coils were used for MRI of intraoral hard and soft tissues. FLASH MRI was applied in vivo with a mandible voxel size of 250 x 250 x 500 μm 3 , FOV of 64 x 64 x 28 mm 3 and acquisition time of 3:57 min and with a maxilla voxel size of 350 μm 3 and FOV of 34 cm 3 in 6:40 min. Ex vivo imaging was performed in 4:38 min, with a resolution of 200 μm 3 and FOV of 36.5 cm 3 . Cone beam (CB) CT of the mandible and subjects were acquired. MRI was compared to CBCT and histological sections. Deviations were calculated with intraclass correlation coefficient (ICC) and coefficient of variation (c v ). A high congruence between CBCT, MRI and specimens was demonstrated. Hard and soft tissues including dental pulp, periodontium, gingiva, cancellous bone and mandibular canal contents were adequately displayed with MRI. Imaging of select intraoral tissues was achieved using custom MRI protocols with an easily applicable intraoral coil in a clinically acceptable acquisition time. Comparison with CBCT and histological sections helped demonstrate dimensional accuracy of the MR images. The course of the mandibular canal was accurately displayed with CBCT and MRI. (orig.)

  8. Simple luminosity normalization of greenness, yellowness and redness/greenness for comparison of leaf spectral profiles in multi-temporally acquired remote sensing images.

    Science.gov (United States)

    Doi, Ryoichi

    2012-09-01

    Observation of leaf colour (spectral profiles) through remote sensing is an effective method of identifying the spatial distribution patterns of abnormalities in leaf colour, which enables appropriate plant management measures to be taken. However, because the brightness of remote sensing images varies with acquisition time, in the observation of leaf spectral profiles in multi-temporally acquired remote sensing images, changes in brightness must be taken into account. This study identified a simple luminosity normalization technique that enables leaf colours to be compared in remote sensing images over time. The intensity values of green and yellow (green+red) exhibited strong linear relationships with luminosity (R2 greater than 0.926) when various invariant rooftops in Bangkok or Tokyo were spectralprofiled using remote sensing images acquired at different time points. The values of the coefficient and constant or the coefficient of the formulae describing the intensity of green or yellow were comparable among the single Bangkok site and the two Tokyo sites, indicating the technique's general applicability. For single rooftops, the values of the coefficient of variation for green, yellow, and red/green were 16% or less (n=6-11), indicating an accuracy not less than those of well-established remote sensing measures such as the normalized difference vegetation index. After obtaining the above linear relationships, raw intensity values were normalized and a temporal comparison of the spectral profiles of the canopies of evergreen and deciduous tree species in Tokyo was made to highlight the changes in the canopies' spectral profiles. Future aspects of this technique are discussed herein.

  9. 3D spectrum imaging of multi-wall carbon nanotube coupled π-surface modes utilising electron energy-loss spectra acquired using a STEM/Enfina system

    International Nuclear Information System (INIS)

    Seepujak, A.; Bangert, U.; Gutierrez-Sosa, A.; Harvey, A.J.; Blank, V.D.; Kulnitskiy, B.A.; Batov, D.V.

    2005-01-01

    Numerous studies have utilised electron energy-loss (EEL) spectra acquired in the plasmon (2-10 eV) regime in order to probe delocalised π-electronic states of multi-wall carbon nanotubes (MWCNTs). Interpretation of electron energy loss (EEL) spectra of MWCNTs in the 2-10 eV regime. Carbon (accepted for publication); Blank et al. J. Appl. Phys. 91 (2002) 1657). In the present contribution, EEL spectra were acquired from a 2D raster defined on a bottle-shaped MWCNT, using a Gatan UHV Enfina system attached to a dedicated scanning transmission electron microscope (STEM). The technique utilised to isolate and sequentially filter each of the volume and surface resonances is described in detail. Utilising a scale for the intensity of a filtered mode enables one to 'see' the distribution of each resonance in the raster. This enables striking 3D resonance-filtered spectrum images (SIs) of π-collective modes to be observed. Red-shift of the lower energy split π-surface resonance provides explicit evidence of π-surface mode coupling predicted for thin graphitic films (Lucas et al. Phys. Rev. B 49 (1994) 2888). Resonance-filtered SIs are also compared to non-filtered SIs with suppressed surface contributions, acquired utilising a displaced collector aperture. The present filtering technique is seen to isolate surface contributions more effectively, and without the significant loss of statistics, associated with the displaced collector aperture mode. Isolation of collective modes utilising 3D resonance-filtered spectrum imaging, demonstrates a valuable method for 'pinpointing' the location of discrete modes in irregularly shaped nanostructures

  10. PET imaging of HSV1-tk mutants with acquired specificity toward pyrimidine- and acycloguanosine-based radiotracers

    Energy Technology Data Exchange (ETDEWEB)

    Likar, Yury; Dobrenkov, Konstantin; Olszewska, Malgorzata; Shenker, Larissa; Hricak, Hedvig; Ponomarev, Vladimir [Memorial Sloan-Kettering Cancer Center, Molecular Imaging Laboratory, Department of Radiology, New York, NY (United States); Cai, Shangde [Memorial Sloan-Kettering Cancer Center, Radiochemistry/Cyclotron Core Facility, New York, NY (United States)

    2009-08-15

    The aim of this study was to create an alternative mutant of the herpes simplex virus type 1 thymidine kinase (HSV1-tk) reporter gene with reduced phosphorylation capacity for acycloguanosine derivatives, but not pyrimidine-based compounds that will allow for successful PET imaging. A new mutant of HSV1-tk reporter gene, suitable for PET imaging using pyrimidine-based radiotracers, was developed. The HSV1-tk mutant contains an arginine-to-glutamine substitution at position 176 (HSV1-R176Qtk) of the nucleoside binding region of the enzyme. The mutant-gene product showed favorable enzymatic characteristics toward pyrimidine-based nucleosides, while exhibiting reduced activity with acycloguanosine derivatives. In order to enhance HSV1-R176Qtk reporter activity with pyrimidine-based radiotracers, we introduced the R176Q substitution into the more active HSV1-sr39tk mutant. U87 human glioma cells transduced with the HSV1-R176Qsr39tk double mutant reporter gene showed high {sup 3}H-FEAU pyrimidine nucleoside and low {sup 3}H-penciclovir acycloguanosine analog uptake in vitro. PET imaging also demonstrated high {sup 18}F-FEAU and low {sup 18}F-FHBG accumulation in HSV1-R176Qsr39tk+ xenografts. The feasibility of imaging two independent nucleoside-specific HSV1-tk mutants in the same animal with PET was demonstrated. Two opposite xenografts expressing the HSV1-R176Qsr39tk reporter gene and the previously described acycloguanosine-specific mutant of HSV1-tk, HSV1-A167Ysr39tk reporter gene, were imaged using a short-lived pyrimidine-based {sup 18}F-FEAU and an acycloguanosine-based {sup 18}F-FHBG radiotracer, respectively, administered on 2 consecutive days. We conclude that in combination with acycloguanosine-specific HSV1-A167Ysr39tk reporter gene, a HSV1-tk mutant containing the R176Q substitution could be used for PET imaging of two different cell populations or concurrent molecular biological processes in the same living subject. (orig.)

  11. Selection of optimal pulse sequences for conventional and dynamic MR imaging with Gd-DTPA; A fundamental study

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, Miho; Kita, Keisuke; Maeda, Masayuki (Wakayama Medical Coll. (Japan)) (and others)

    1989-11-01

    Gadolinium-DTPA (Gd-DTPA) enhances contrast between tissues in magnetic resonance (MR) imaging. The enhancement of tissues depends partly upon the pulse sequences, and the optimal pulse sequence is also influenced by the tissue cncentration of Gd-DTPA. We prepared phantoms of 25% albumin solutions with various concentrations of Gd-DTPA, and imaged them using various pulse sequences with 1.5-T MR system. We also performed MR imaging of 16 patients with tumors (10 brain tumors and 6 hepatic tumors) before and after intravenous administration of Gd-DTPA (0.1 mmol/kg); 6 patients with hepatic tumors underwent dynamic MR imaging during suspended respiration. We made a theoretical equation to calculate the concentration of Gd-DTPA and estimated its tissue concentration in tumors at 0{approx}0.2 mmol/kg. Within these tissue concentrations, the enhancement-to-noise (E/N) ratio was larger in FISP (flip angle of 90deg, TR pf 300 msec, minimal TE) and SE (TR of 400 msec, minimal TE) sequences than in other sequences observed. These sequences may be preferable for conventional enhanced-MRI. Among the pulse sequences with TR of less than 100 msec, FISP (flip angle of 90deg, TR of less than 100 msec, minimal TE) had the largest E/N ratio; which may be useful for dynamic MRI during suspended respiration. The importance of selecting the optimal pulse sequences according to the imaging modality used will be discussed. (author).

  12. MEASUREMENT OF LARGE-SCALE SOLAR POWER PLANT BY USING IMAGES ACQUIRED BY NON-METRIC DIGITAL CAMERA ON BOARD UAV

    Directory of Open Access Journals (Sweden)

    R. Matsuoka

    2012-07-01

    Full Text Available This paper reports an experiment conducted in order to investigate the feasibility of the deformation measurement of a large-scale solar power plant on reclaimed land by using images acquired by a non-metric digital camera on board a micro unmanned aerial vehicle (UAV. It is required that a root mean squares of errors (RMSE in height measurement should be less than 26 mm that is 1/3 of the critical limit of deformation of 78 mm off the plane of a solar panel. Images utilized in the experiment have been obtained by an Olympus PEN E-P2 digital camera on board a Microdrones md4-1000 quadrocopter. The planned forward and side overlap ratios of vertical image acquisition have been 60 % and 60 % respectively. The planned flying height of the UAV has been 20 m above the ground level and the ground resolution of an image is approximately 5.0 mm by 5.0 mm. 8 control points around the experiment area are utilized for orientation. Measurement results are evaluated by the space coordinates of 220 check points which are corner points of 55 solar panels selected from 1768 solar panels in the experiment area. Two teams engage in the experiment. One carries out orientation and measurement by using 171 images following the procedure of conventional aerial photogrammetry, and the other executes those by using 126 images in the manner of close range photogrammetry. The former fails to satisfy the required accuracy, while the RMSE in height measurement by the latter is 8.7 mm that satisfies the required accuracy. From the experiment results, we conclude that the deformation measurement of a large-scale solar power plant on reclaimed land by using images acquired by a nonmetric digital camera on board a micro UAV would be feasible if points utilized in orientation and measurement have a sufficient number of bundles in good geometry and self-calibration in orientation is carried out.

  13. A new feedback image encryption scheme based on perturbation with dynamical compound chaotic sequence cipher generator

    Science.gov (United States)

    Tong, Xiaojun; Cui, Minggen; Wang, Zhu

    2009-07-01

    The design of the new compound two-dimensional chaotic function is presented by exploiting two one-dimensional chaotic functions which switch randomly, and the design is used as a chaotic sequence generator which is proved by Devaney's definition proof of chaos. The properties of compound chaotic functions are also proved rigorously. In order to improve the robustness against difference cryptanalysis and produce avalanche effect, a new feedback image encryption scheme is proposed using the new compound chaos by selecting one of the two one-dimensional chaotic functions randomly and a new image pixels method of permutation and substitution is designed in detail by array row and column random controlling based on the compound chaos. The results from entropy analysis, difference analysis, statistical analysis, sequence randomness analysis, cipher sensitivity analysis depending on key and plaintext have proven that the compound chaotic sequence cipher can resist cryptanalytic, statistical and brute-force attacks, and especially it accelerates encryption speed, and achieves higher level of security. By the dynamical compound chaos and perturbation technology, the paper solves the problem of computer low precision of one-dimensional chaotic function.

  14. Time integration and statistical regulation applied to mobile objects detection in a sequence of images

    International Nuclear Information System (INIS)

    Letang, Jean-Michel

    1993-01-01

    This PhD thesis deals with the detection of moving objects in monocular image sequences. The first section presents the inherent problems of motion analysis in real applications. We propose a method robust to perturbations frequently encountered during acquisition of outdoor scenes. It appears three main directions for investigations, all of them pointing out the importance of the temporal axis, which is a specific dimension for motion analysis. In the first part, the image sequence is considered as a set of temporal signals. The temporal multi-scale decomposition enables the characterization of various dynamical behaviors of the objects being in the scene at a given instant. A second module integrates motion information. This elementary trajectography of moving objects provides a temporal prediction map, giving a confidence level of motion presence. Interactions between both sets of data are expressed within a statistical regularization. Markov random field models supply a formal framework to convey a priori knowledge of the primitives to be evaluated. A calibration method with qualitative boxes is presented to estimate model parameters. Our approach requires only simple computations and leads to a rather fast algorithm, that we evaluate in the last section over various typical sequences. (author) [fr

  15. An artificial intelligence based improved classification of two-phase flow patterns with feature extracted from acquired images.

    Science.gov (United States)

    Shanthi, C; Pappa, N

    2017-05-01

    Flow pattern recognition is necessary to select design equations for finding operating details of the process and to perform computational simulations. Visual image processing can be used to automate the interpretation of patterns in two-phase flow. In this paper, an attempt has been made to improve the classification accuracy of the flow pattern of gas/ liquid two- phase flow using fuzzy logic and Support Vector Machine (SVM) with Principal Component Analysis (PCA). The videos of six different types of flow patterns namely, annular flow, bubble flow, churn flow, plug flow, slug flow and stratified flow are recorded for a period and converted to 2D images for processing. The textural and shape features extracted using image processing are applied as inputs to various classification schemes namely fuzzy logic, SVM and SVM with PCA in order to identify the type of flow pattern. The results obtained are compared and it is observed that SVM with features reduced using PCA gives the better classification accuracy and computationally less intensive than other two existing schemes. This study results cover industrial application needs including oil and gas and any other gas-liquid two-phase flows. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  16. Evaluation of chirp reversal power modulation sequence for contrast agent imaging

    International Nuclear Information System (INIS)

    Novell, A; Sennoga, CA; Escoffre, JM; Chaline, J; Bouakaz, A

    2014-01-01

    Over the last decade, significant research effort has been focused on the use of chirp for contrast agent imaging because chirps are known to significantly increase imaging contrast-to-noise ratio (CNR). New imaging schemes, such as chirp reversal (CR), have been developed to improve contrast detection by increasing non-linear microbubble responses. In this study we evaluated the contrast enhancement efficiency of various chirped imaging sequences in combination with well-established imaging schemes such as power modulation (PM) and pulse inversion (PI). The imaging schemes tested were implemented on a fully programmable open scanner and evaluated by ultrasonically scanning (excitation frequency of 2.5 MHz; amplitude of 350 kPa) a tissue-mimicking flow phantom comprising a 4 mm diameter tube through which aqueous dispersions (dilution fraction of 1/2000) of the commercial ultrasound contrast agent, SonoVue ® were continuously circulated. The recovery of non-linear microbubble responses after chirp compression requires the development and the optimization of a specific filter. A compression filter was therefore designed and used to compress and extract several non-linear components from the received microbubble responses. The results showed that using chirps increased the image CNR by approximately 10 dB, as compared to conventional Gaussian apodized sine burst excitation but degraded the axial resolution by a factor of 1.4, at −3 dB. We demonstrated that the highest CNR and contrast-to-noise ratio (CTR) were achievable when CR was combined with PM as compared to other imaging schemes such as PI. (paper)

  17. External scintigraphy in monitoring the behavior of pharmaceutical formulations in vivo I: technique for acquiring high-resolution images of tablets

    International Nuclear Information System (INIS)

    Theodorakis, M.C.; Simpson, D.R.; Leung, D.M.; Devous, M. Sr.

    1983-01-01

    A new method for monitoring tablet disintegration in vivo was developed. In this method, the tablets were labeled with a short-lived radionuclide, technetium 99m, and monitored by a gamma camera. Several innovations were introduced with this method. First, computer reconstruction algorithms were used to enhance the scintigraphic images of the disintegrating tablet in vivo. Second, the use of a four-pinhole collimator to acquire multiple views of the tablet resulted in high count rates and reduced acquisition times of the scintigraphic images. Third, the magnification of the scintigraphic images achieved by pinhole collimation led to significant improvement in resolution. Fourth, the radioinuclide was incorporated into the granulation so that the whole mass of the tablet was uniformly labeled with high levels of activity. This technique allowed the continuous monitoring of the disintegration process of tablets in vivo in experimental animals. Multiple pinhole collimation and the labeling process permitted the acquisition of quality scintigraphic images of the labeled tablet every 30 sec. The resolution of the method was tested in vitro and in vivo

  18. An automated computerized methodology for the segmentation of in vivo acquired DSA images: application in the New Zealand hindlimb ischemia model

    International Nuclear Information System (INIS)

    Kagadis, G C; Daskalakis, A; Spyridonos, P; Nikiforidis, G C; Diamantopoulos, A; Samaras, N; Katsanos, K; Karnabatidis, D; Siablis, D; Sourgiadaki, E; Cavouras, D

    2009-01-01

    In-vivo dynamic visualization and accurate quantification of vascular networks is a prerequisite of crucial importance in both therapeutic angiogenesis and tumor anti-angiogenesis studies. A user independent computerized tool was developed, for the automated segmentation and quantitative assessment of in-vivo acquired DSA images. Automatic vessel assessment was performed employing the concept of image structural tensor. Initially, vasculature was estimated according to the largest eigenvalue of the structural tensor. The resulted eigenvalue matrix was treated as gray-matrix from which the vessels were gradually segmented and then categorized in three main sub-groups; large, medium and small-size vessels. The histogram percentiles, corresponding to 85%, 65% and 47% of prime eigenvalue gray-matrix were optimally found to give the thresholds T1, T2 and T3 respectively, for extracting vessels of different size. The proposed methodology was tested on a series of DSA images in both normal rabbits (group A) and in rabbits with experimental induced chronic hindlimb ischemia (group B). As a result an automated computerized tool was developed to process images without any user intervention in either experimental or clinical studies. Specifically, a higher total vascular area and length were calculated in group B compared to group A (p=0.0242 and p=0.0322 respectively), which is in accordance to the fact that significantly more collateral arteries are developed during the physiological response to the stimuli of ischemia.

  19. Managing complex processing of medical image sequences by program supervision techniques

    Science.gov (United States)

    Crubezy, Monica; Aubry, Florent; Moisan, Sabine; Chameroy, Virginie; Thonnat, Monique; Di Paola, Robert

    1997-05-01

    Our objective is to offer clinicians wider access to evolving medical image processing (MIP) techniques, crucial to improve assessment and quantification of physiological processes, but difficult to handle for non-specialists in MIP. Based on artificial intelligence techniques, our approach consists in the development of a knowledge-based program supervision system, automating the management of MIP libraries. It comprises a library of programs, a knowledge base capturing the expertise about programs and data and a supervision engine. It selects, organizes and executes the appropriate MIP programs given a goal to achieve and a data set, with dynamic feedback based on the results obtained. It also advises users in the development of new procedures chaining MIP programs.. We have experimented the approach for an application of factor analysis of medical image sequences as a means of predicting the response of osteosarcoma to chemotherapy, with both MRI and NM dynamic image sequences. As a result our program supervision system frees clinical end-users from performing tasks outside their competence, permitting them to concentrate on clinical issues. Therefore our approach enables a better exploitation of possibilities offered by MIP and higher quality results, both in terms of robustness and reliability.

  20. Diagnostic value of the fast-FLAIR sequence in MR imaging of intracranial tumors

    International Nuclear Information System (INIS)

    Husstedt, H.W.; Sickert, M.; Koestler, H.; Haubitz, B.; Becker, H.

    2000-01-01

    The aim of this study was to quantify imaging characteristics of fast fluid-attenuated inversion recovery (FLAIR) sequence in brain tumors compared with T1-postcontrast- and T2-sequences. Fast-FLAIR-, T2 fast spin echo (FSE)-, and T1 SE postcontrast images of 74 patients with intracranial neoplasms were analyzed. Four neuroradiologists rated signal intensity and inhomogeneity of the tumor, rendering of cystic parts, demarcation of the tumor vs brain, of the tumor vs edema and of brain vs edema, as well as the presence of motion and of other artifacts. Data analysis was performed for histologically proven astrocytomas, glioblastomas, and meningiomas, for tumors with poor contrast enhancement, and for all patients pooled. Only for tumors with poor contrast enhancement (n = 12) did fast FLAIR provide additional information about the lesion. In these cases, signal intensity, demarcation of the tumor vs brain, and differentiation of the tumor vs edema were best using fast FLAIR. In all cases, rendering of the tumor's inner structure was poor. For all other tumor types, fast FLAIR did not give clinically relevant information, the only exception being a better demarcation of the edema from brain tissue. Artifacts rarely interfered with evaluation of fast-FLAIR images. Thus, fast FLAIR cannot replace T2-weighted series. It provides additional information only in tumors with poor contrast enhancement. It is helpful for defining the exact extent of the edema of any tumor but gives little information about their inner structure. (orig.)

  1. Diagnostic value of the fast-FLAIR sequence in MR imaging of intracranial tumors.

    Science.gov (United States)

    Husstedt, H W; Sickert, M; Köstler, H; Haubitz, B; Becker, H

    2000-01-01

    The aim of this study was to quantify imaging characteristics of fast fluid-attenuated inversion recovery (FLAIR) sequence in brain tumors compared with T1-postcontrast- and T2-sequences. Fast-FLAIR-, T2 fast spin echo (FSE)-, and T1 SE postcontrast images of 74 patients with intracranial neoplasms were analyzed. Four neuroradiologists rated signal intensity and inhomogeneity of the tumor, rendering of cystic parts, demarcation of the tumor vs brain, of the tumor vs edema and of brain vs edema, as well as the presence of motion and of other artifacts. Data analysis was performed for histologically proven astrocytomas, glioblastomas, and meningiomas, for tumors with poor contrast enhancement, and for all patients pooled. Only for tumors with poor contrast enhancement (n = 12) did fast FLAIR provide additional information about the lesion. In these cases, signal intensity, demarcation of the tumor vs brain, and differentiation of the tumor vs edema were best using fast FLAIR. In all cases, rendering of the tumor's inner structure was poor. For all other tumor types, fast FLAIR did not give clinically relevant information, the only exception being a better demarcation of the edema from brain tissue. Artifacts rarely interfered with evaluation of fast-FLAIR images. Thus, fast FLAIR cannot replace T2-weighted series. It provides additional information only in tumors with poor contrast enhancement. It is helpful for defining the exact extent of the edema of any tumor but gives little information about their inner structure.

  2. Analysis of the quality of image data acquired by the LANDSAT-4 thematic mapper and multispectral scanners. [Central Valley, California

    Science.gov (United States)

    Colwell, R. N. (Principal Investigator)

    1983-01-01

    Image products and numeric data were extracted from both TM and MSS data in an effort to evaluate the quality of these data for interpreting major agricultural resources and conditions in California's Central Valley. The utility of TM data appears excellent for meeting most of the inventory objectives of the agricultural resource specialist. These data should be extremely valuable for crop type and area proportion estimation, for updating agricultural land use survey maps at 1:24,000-scale and smaller, for field boundary definition, and for determining the size and location of individual farmsteads.

  3. Deep sequencing and flow cytometric characterization of expanded effector memory CD8+CD57+ T cells frequently reveals T-cell receptor Vβ oligoclonality and CDR3 homology in acquired aplastic anemia.

    Science.gov (United States)

    Giudice, Valentina; Feng, Xingmin; Lin, Zenghua; Hu, Wei; Zhang, Fanmao; Qiao, Wangmin; Ibanez, Maria Del Pilar Fernandez; Rios, Olga; Young, Neal S

    2018-05-01

    Oligoclonal expansion of CD8 + CD28 - lymphocytes has been considered indirect evidence for a pathogenic immune response in acquired aplastic anemia. A subset of CD8 + CD28 - cells with CD57 expression, termed effector memory cells, is expanded in several immune-mediated diseases and may have a role in immune surveillance. We hypothesized that effector memory CD8 + CD28 - CD57 + cells may drive aberrant oligoclonal expansion in aplastic anemia. We found CD8 + CD57 + cells frequently expanded in the blood of aplastic anemia patients, with oligoclonal characteristics by flow cytometric Vβ usage analysis: skewing in 1-5 Vβ families and frequencies of immunodominant clones ranging from 1.98% to 66.5%. Oligoclonal characteristics were also observed in total CD8 + cells from aplastic anemia patients with CD8 + CD57 + cell expansion by T-cell receptor deep sequencing, as well as the presence of 1-3 immunodominant clones. Oligoclonality was confirmed by T-cell receptor repertoire deep sequencing of enriched CD8 + CD57 + cells, which also showed decreased diversity compared to total CD4 + and CD8 + cell pools. From analysis of complementarity-determining region 3 sequences in the CD8 + cell pool, a total of 29 sequences were shared between patients and controls, but these sequences were highly expressed in aplastic anemia subjects and also present in their immunodominant clones. In summary, expansion of effector memory CD8 + T cells is frequent in aplastic anemia and mirrors Vβ oligoclonal expansion. Flow cytometric Vβ usage analysis combined with deep sequencing technologies allows high resolution characterization of the T-cell receptor repertoire, and might represent a useful tool in the diagnosis and periodic evaluation of aplastic anemia patients. (Registered at clinicaltrials.gov identifiers: 00001620, 01623167, 00001397, 00071045, 00081523, 00961064 ). Copyright © 2018 Ferrata Storti Foundation.

  4. Sensor Fusion of a Mobile Device to Control and Acquire Videos or Images of Coffee Branches and for Georeferencing Trees

    Directory of Open Access Journals (Sweden)

    Paula Jimena Ramos Giraldo

    2017-04-01

    Full Text Available Smartphones show potential for controlling and monitoring variables in agriculture. Their processing capacity, instrumentation, connectivity, low cost, and accessibility allow farmers (among other users in rural areas to operate them easily with applications adjusted to their specific needs. In this investigation, the integration of inertial sensors, a GPS, and a camera are presented for the monitoring of a coffee crop. An Android-based application was developed with two operating modes: (i Navigation: for georeferencing trees, which can be as close as 0.5 m from each other; and (ii Acquisition: control of video acquisition, based on the movement of the mobile device over a branch, and measurement of image quality, using clarity indexes to select the most appropriate frames for application in future processes. The integration of inertial sensors in navigation mode, shows a mean relative error of ±0.15 m, and total error ±5.15 m. In acquisition mode, the system correctly identifies the beginning and end of mobile phone movement in 99% of cases, and image quality is determined by means of a sharpness factor which measures blurriness. With the developed system, it will be possible to obtain georeferenced information about coffee trees, such as their production, nutritional state, and presence of plagues or diseases.

  5. Sensor Fusion of a Mobile Device to Control and Acquire Videos or Images of Coffee Branches and for Georeferencing Trees.

    Science.gov (United States)

    Giraldo, Paula Jimena Ramos; Aguirre, Álvaro Guerrero; Muñoz, Carlos Mario; Prieto, Flavio Augusto; Oliveros, Carlos Eugenio

    2017-04-06

    Smartphones show potential for controlling and monitoring variables in agriculture. Their processing capacity, instrumentation, connectivity, low cost, and accessibility allow farmers (among other users in rural areas) to operate them easily with applications adjusted to their specific needs. In this investigation, the integration of inertial sensors, a GPS, and a camera are presented for the monitoring of a coffee crop. An Android-based application was developed with two operating modes: ( i ) Navigation: for georeferencing trees, which can be as close as 0.5 m from each other; and ( ii ) Acquisition: control of video acquisition, based on the movement of the mobile device over a branch, and measurement of image quality, using clarity indexes to select the most appropriate frames for application in future processes. The integration of inertial sensors in navigation mode, shows a mean relative error of ±0.15 m, and total error ±5.15 m. In acquisition mode, the system correctly identifies the beginning and end of mobile phone movement in 99% of cases, and image quality is determined by means of a sharpness factor which measures blurriness. With the developed system, it will be possible to obtain georeferenced information about coffee trees, such as their production, nutritional state, and presence of plagues or diseases.

  6. A new classification method for MALDI imaging mass spectrometry data acquired on formalin-fixed paraffin-embedded tissue samples.

    Science.gov (United States)

    Boskamp, Tobias; Lachmund, Delf; Oetjen, Janina; Cordero Hernandez, Yovany; Trede, Dennis; Maass, Peter; Casadonte, Rita; Kriegsmann, Jörg; Warth, Arne; Dienemann, Hendrik; Weichert, Wilko; Kriegsmann, Mark

    2017-07-01

    Matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS) shows a high potential for applications in histopathological diagnosis, and in particular for supporting tumor typing and subtyping. The development of such applications requires the extraction of spectral fingerprints that are relevant for the given tissue and the identification of biomarkers associated with these spectral patterns. We propose a novel data analysis method based on the extraction of characteristic spectral patterns (CSPs) that allow automated generation of classification models for spectral data. Formalin-fixed paraffin embedded (FFPE) tissue samples from N=445 patients assembled on 12 tissue microarrays were analyzed. The method was applied to discriminate primary lung and pancreatic cancer, as well as adenocarcinoma and squamous cell carcinoma of the lung. A classification accuracy of 100% and 82.8%, resp., could be achieved on core level, assessed by cross-validation. The method outperformed the more conventional classification method based on the extraction of individual m/z values in the first application, while achieving a comparable accuracy in the second. LC-MS/MS peptide identification demonstrated that the spectral features present in selected CSPs correspond to peptides relevant for the respective classification. This article is part of a Special Issue entitled: MALDI Imaging, edited by Dr. Corinna Henkel and Prof. Peter Hoffmann. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. TU-H-CAMPUS-IeP3-02: Neurovascular 4D Parametric Imaging Using Co-Registration of Biplane DSA Sequences with 3D Vascular Geometry Obtained From Cone Beam CT

    Energy Technology Data Exchange (ETDEWEB)

    Balasubramoniam, A; Bednarek, D; Rudin, S; Ionita, C [Toshiba Stroke and Vascular Research Centre, SUNY at Buffalo (United States)

    2016-06-15

    Purpose: To create 4D parametric images using biplane Digital Subtraction Angiography (DSA) sequences co-registered with the 3D vascular geometry obtained from Cone Beam-CT (CBCT). Methods: We investigated a method to derive multiple 4D Parametric Imaging (PI) maps using only one CBCT acquisition. During this procedure a 3D-DSA geometry is stored and used subsequently for all 4D images. Each time a biplane DSA is acquired, we calculate 2D parametric maps of Bolus Arrival Time (BAT), Mean Transit Time (MTT) and Time to Peak (TTP). Arterial segments which are nearly parallel with one of the biplane imaging planes in the 2D parametric maps are co-registered with the 3D geometry. The values in the remaining vascular network are found using spline interpolation since the points chosen for co-registration on the vasculature are discrete and remaining regions need to be interpolated. To evaluate the method we used a patient CT volume data set for 3D printing a neurovascular phantom containing a complete Circle of Willis. We connected the phantom to a flow loop with a peristaltic pump, simulating physiological flow conditions. Contrast media was injected with an automatic injector at 10 ml/sec. Images were acquired with a Toshiba Infinix C-arm and 4D parametric image maps of the vasculature were calculated. Results: 4D BAT, MTT, and TTP parametric image maps of the Circle of Willis were derived. We generated color-coded 3D geometries which avoided artifacts due to vessel overlap or foreshortening in the projection direction. Conclusion: The software was tested successfully and multiple 4D parametric images were obtained from biplane DSA sequences without the need to acquire additional 3D-DSA runs. This can benefit the patient by reducing the contrast media and the radiation dose normally associated with these procedures. Partial support from NIH Grant R01-EB002873 and Toshiba Medical Systems Corp.

  8. TU-H-CAMPUS-IeP3-02: Neurovascular 4D Parametric Imaging Using Co-Registration of Biplane DSA Sequences with 3D Vascular Geometry Obtained From Cone Beam CT

    International Nuclear Information System (INIS)

    Balasubramoniam, A; Bednarek, D; Rudin, S; Ionita, C

    2016-01-01

    Purpose: To create 4D parametric images using biplane Digital Subtraction Angiography (DSA) sequences co-registered with the 3D vascular geometry obtained from Cone Beam-CT (CBCT). Methods: We investigated a method to derive multiple 4D Parametric Imaging (PI) maps using only one CBCT acquisition. During this procedure a 3D-DSA geometry is stored and used subsequently for all 4D images. Each time a biplane DSA is acquired, we calculate 2D parametric maps of Bolus Arrival Time (BAT), Mean Transit Time (MTT) and Time to Peak (TTP). Arterial segments which are nearly parallel with one of the biplane imaging planes in the 2D parametric maps are co-registered with the 3D geometry. The values in the remaining vascular network are found using spline interpolation since the points chosen for co-registration on the vasculature are discrete and remaining regions need to be interpolated. To evaluate the method we used a patient CT volume data set for 3D printing a neurovascular phantom containing a complete Circle of Willis. We connected the phantom to a flow loop with a peristaltic pump, simulating physiological flow conditions. Contrast media was injected with an automatic injector at 10 ml/sec. Images were acquired with a Toshiba Infinix C-arm and 4D parametric image maps of the vasculature were calculated. Results: 4D BAT, MTT, and TTP parametric image maps of the Circle of Willis were derived. We generated color-coded 3D geometries which avoided artifacts due to vessel overlap or foreshortening in the projection direction. Conclusion: The software was tested successfully and multiple 4D parametric images were obtained from biplane DSA sequences without the need to acquire additional 3D-DSA runs. This can benefit the patient by reducing the contrast media and the radiation dose normally associated with these procedures. Partial support from NIH Grant R01-EB002873 and Toshiba Medical Systems Corp.

  9. Diuretic-enhanced gadolinium excretory MR urography: comparison of conventional gradient-echo sequences and echo-planar imaging

    Energy Technology Data Exchange (ETDEWEB)

    Nolte-Ernsting, C.C.A.; Tacke, J.; Adam, G.B.; Haage, P.; Guenther, R.W. [Univ. of Technology, Aachen (Germany). Dept. of Diagnostic Radiology; Jung, P.; Jakse, G. [Univ. of Technology, Aachen (Germany). Dept. of Urology

    2001-01-01

    The aim of this study was to investigate the utility of different gadolinium-enhanced T1-weighted gradient-echo techniques in excretory MR urography. In 74 urologic patients, excretory MR urography was performed using various T1-weighted gradient-echo (GRE) sequences after injection of gadolinium-DTPA and low-dose furosemide. The examinations included conventional GRE sequences and echo-planar imaging (GRE EPI), both obtained with 3D data sets and 2D projection images. Breath-hold acquisition was used primarily. In 20 of 74 examinations, we compared breath-hold imaging with respiratory gating. Breath-hold imaging was significantly superior to respiratory gating for the visualization of pelvicaliceal systems, but not for the ureters. Complete MR urograms were obtained within 14-20 s using 3D GRE EPI sequences and in 20-30 s with conventional 3D GRE sequences. Ghost artefacts caused by ureteral peristalsis often occurred with conventional 3D GRE imaging and were almost completely suppressed in EPI sequences (p < 0.0001). Susceptibility effects were more pronounced on GRE EPI MR urograms and calculi measured 0.8-21.7% greater in diameter compared with conventional GRE sequences. Increased spatial resolution degraded the image quality only in GRE-EPI urograms. (orig.)

  10. Analysis of the quality of image data acquired by the LANDSAT-4 Thematic Mapper and Multispectral Scanners

    Science.gov (United States)

    Colwell, R. N. (Principal Investigator)

    1984-01-01

    The geometric quality of TM film and digital products is evaluated by making selective photomeasurements and by measuring the coordinates of known features on both the TM products and map products. These paired observations are related using a standard linear least squares regression approach. Using regression equations and coefficients developed from 225 (TM film product) and 20 (TM digital product) control points, map coordinates of test points are predicted. The residual error vectors and analysis of variance (ANOVA) were performed on the east and north residual using nine image segments (blocks) as treatments. Based on the root mean square error of the 223 (TM film product) and 22 (TM digital product) test points, users of TM data expect the planimetric accuracy of mapped points to be within 91 meters and within 117 meters for the film products, and to be within 12 meters and within 14 meters for the digital products.

  11. Analysis of the quality of image data acquired by the LANDSAT-4 thematic mapper and multispectral scanners. [Plumas County, California

    Science.gov (United States)

    Colwell, R. N. (Principal Investigator)

    1984-01-01

    A seven step procedure developed for evaluating the geometric properties of MSS and TM film produces is being implemented. Some 476 control points were selected of which 238 are being tested and edited for digitization and scaling errors. Tables show statistics established for assessing the spectral characteristics and variability, as well as the spatial resolution and radiometric sensitivity of TM data for a forest environment in an effort to determine the extent to which major forest cover type can be detected and identified on TM digital and image products. Results thus far show that the high quality obtained are more than sufficient for meeting most of the inventory objectives of the renewable resource specialist. The TM data should be extremely valuable for: (1) estimating forest cover types; (2) updating land use survey maps; and (3) determining the size and shape and location of individual forest clearings and water resources.

  12. Color Image Encryption Using Three-Dimensional Sine ICMIC Modulation Map and DNA Sequence Operations

    Science.gov (United States)

    Liu, Wenhao; Sun, Kehui; He, Yi; Yu, Mengyao

    Derived from Sine map and iterative chaotic map with infinite collapse (ICMIC), a three-dimensional hyperchaotic Sine ICMIC modulation map (3D-SIMM) is proposed based on a close-loop modulation coupling (CMC) method. Based on this map, a novel color image encryption algorithm is designed by employing a hybrid model of multidirectional circular permutation and deoxyribonucleic acid (DNA) masking. In this scheme, the pixel positions of image are scrambled by multidirectional circular permutation, and the pixel values are substituted by DNA sequence operations. The simulation results and security analysis show that the algorithm has good encryption effect and strong key sensitivity, and can resist brute-force, statistical, differential, known-plaintext and chosen-plaintext attacks.

  13. Imaging cardiac activation sequence during ventricular tachycardia in a canine model of nonischemic heart failure.

    Science.gov (United States)

    Han, Chengzong; Pogwizd, Steven M; Yu, Long; Zhou, Zhaoye; Killingsworth, Cheryl R; He, Bin

    2015-01-15

    Noninvasive cardiac activation imaging of ventricular tachycardia (VT) is important in the clinical diagnosis and treatment of arrhythmias in heart failure (HF) patients. This study investigated the ability of the three-dimensional cardiac electrical imaging (3DCEI) technique for characterizing the activation patterns of spontaneously occurring and norepinephrine (NE)-induced VTs in a newly developed arrhythmogenic canine model of nonischemic HF. HF was induced by aortic insufficiency followed by aortic constriction in three canines. Up to 128 body-surface ECGs were measured simultaneously with bipolar recordings from up to 232 intramural sites in a closed-chest condition. Data analysis was performed on the spontaneously occurring VTs (n=4) and the NE-induced nonsustained VTs (n=8) in HF canines. Both spontaneously occurring and NE-induced nonsustained VTs initiated by a focal mechanism primarily from the subendocardium, but occasionally from the subepicardium of left ventricle. Most focal initiation sites were located at apex, right ventricular outflow tract, and left lateral wall. The NE-induced VTs were longer, more rapid, and had more focal sites than the spontaneously occurring VTs. Good correlation was obtained between imaged activation sequence and direct measurements (averaged correlation coefficient of ∼0.70 over 135 VT beats). The reconstructed initiation sites were ∼10 mm from measured initiation sites, suggesting good localization in such a large animal model with cardiac size similar to a human. Both spontaneously occurring and NE-induced nonsustained VTs had focal initiation in this canine model of nonischemic HF. 3DCEI is feasible to image the activation sequence and help define arrhythmia mechanism of nonischemic HF-associated VTs. Copyright © 2015 the American Physiological Society.

  14. Digital Sequences and a Time Reversal-Based Impact Region Imaging and Localization Method

    Science.gov (United States)

    Qiu, Lei; Yuan, Shenfang; Mei, Hanfei; Qian, Weifeng

    2013-01-01

    To reduce time and cost of damage inspection, on-line impact monitoring of aircraft composite structures is needed. A digital monitor based on an array of piezoelectric transducers (PZTs) is developed to record the impact region of impacts on-line. It is small in size, lightweight and has low power consumption, but there are two problems with the impact alarm region localization method of the digital monitor at the current stage. The first one is that the accuracy rate of the impact alarm region localization is low, especially on complex composite structures. The second problem is that the area of impact alarm region is large when a large scale structure is monitored and the number of PZTs is limited which increases the time and cost of damage inspections. To solve the two problems, an impact alarm region imaging and localization method based on digital sequences and time reversal is proposed. In this method, the frequency band of impact response signals is estimated based on the digital sequences first. Then, characteristic signals of impact response signals are constructed by sinusoidal modulation signals. Finally, the phase synthesis time reversal impact imaging method is adopted to obtain the impact region image. Depending on the image, an error ellipse is generated to give out the final impact alarm region. A validation experiment is implemented on a complex composite wing box of a real aircraft. The validation results show that the accuracy rate of impact alarm region localization is approximately 100%. The area of impact alarm region can be reduced and the number of PZTs needed to cover the same impact monitoring region is reduced by more than a half. PMID:24084123

  15. MRI of fetal acquired brain lesions

    International Nuclear Information System (INIS)

    Prayer, Daniela; Brugger, Peter C.; Kasprian, Gregor; Witzani, Linde; Helmer, Hanns; Dietrich, Wolfgang; Eppel, Wolfgang; Langer, Martin

    2006-01-01

    Acquired fetal brain damage is suspected in cases of destruction of previously normally formed tissue, the primary cause of which is hypoxia. Fetal brain damage may occur as a consequence of acute or chronic maternal diseases, with acute diseases causing impairment of oxygen delivery to the fetal brain, and chronic diseases interfering with normal, placental development. Infections, metabolic diseases, feto-fetal transfusion syndrome, toxic agents, mechanical traumatic events, iatrogenic accidents, and space-occupying lesions may also qualify as pathologic conditions that initiate intrauterine brain damage. MR manifestations of acute fetal brain injury (such as hemorrhage or acute ischemic lesions) can easily be recognized, as they are hardly different from postnatal lesions. The availability of diffusion-weighted sequences enhances the sensitivity in recognizing acute ischemic lesions. Recent hemorrhages are usually readily depicted on T2 (*) sequences, where they display hypointense signals. Chronic fetal brain injury may be characterized by nonspecific changes that must be attributable to the presence of an acquired cerebral pathology. The workup in suspected acquired fetal brain injury also includes the assessment of extra-CNS organs that may be affected by an underlying pathology. Finally, the placenta, as the organ that mediates oxygen delivery from the maternal circulation to the fetus, must be examined on MR images

  16. MRI of fetal acquired brain lesions

    Energy Technology Data Exchange (ETDEWEB)

    Prayer, Daniela [Department of Radiodiagnostics, Medical University of Vienna (Austria)]. E-mail: daniela.prayer@meduniwien.ac.at; Brugger, Peter C. [Center of Anatomy and Cell Biology, Medical University of Vienna (Austria); Kasprian, Gregor [Department of Radiodiagnostics, Medical University of Vienna (Austria); Witzani, Linde [Department of Radiodiagnostics, Medical University of Vienna (Austria); Helmer, Hanns [Department of Obstetrics and Gynecology, Medical University of Vienna (Austria); Dietrich, Wolfgang [Department of Neurosurgery, Medical University of Vienna (Austria); Eppel, Wolfgang [Department of Obstetrics and Gynecology, Medical University of Vienna (Austria); Langer, Martin [Department of Obstetrics and Gynecology, Medical University of Vienna (Austria)

    2006-02-15

    Acquired fetal brain damage is suspected in cases of destruction of previously normally formed tissue, the primary cause of which is hypoxia. Fetal brain damage may occur as a consequence of acute or chronic maternal diseases, with acute diseases causing impairment of oxygen delivery to the fetal brain, and chronic diseases interfering with normal, placental development. Infections, metabolic diseases, feto-fetal transfusion syndrome, toxic agents, mechanical traumatic events, iatrogenic accidents, and space-occupying lesions may also qualify as pathologic conditions that initiate intrauterine brain damage. MR manifestations of acute fetal brain injury (such as hemorrhage or acute ischemic lesions) can easily be recognized, as they are hardly different from postnatal lesions. The availability of diffusion-weighted sequences enhances the sensitivity in recognizing acute ischemic lesions. Recent hemorrhages are usually readily depicted on T2 (*) sequences, where they display hypointense signals. Chronic fetal brain injury may be characterized by nonspecific changes that must be attributable to the presence of an acquired cerebral pathology. The workup in suspected acquired fetal brain injury also includes the assessment of extra-CNS organs that may be affected by an underlying pathology. Finally, the placenta, as the organ that mediates oxygen delivery from the maternal circulation to the fetus, must be examined on MR images.

  17. Non-destructive assay employing 2D and 3D digital radiographic imaging acquired with thermal neutrons and reactor-produced radioisotopes

    International Nuclear Information System (INIS)

    Silvani, Maria Ines; Almeida, Gevaldo Lisboa de; Lopes, Ricardo T.

    2011-01-01

    The inner structure of some objects can only be visualized by using suitable techniques, when safety reasons or expensive costs preclude the application of invasive procedures. The kind of agent rendering an object partially transparent, unveiling thus its features, depends upon the object size and composition. As a rough rule of thumb, light materials are transparent to gamma and X-rays while the heavy ones are transparent to neutrons. When, after traversing an object, they hit a proper 2-D detector, a radiograph is produced representing a convoluted cross section, called projection, of that object. Taking a large number of such projections for different object attitudes, it is possible to obtain a 3-D tomography of the object as a map of attenuation coefficients. This procedure however, besides a time-consuming task, requires specially tailored equipment and software, not always available or affordable. Yet, in some circumstances it is feasible to replace the 3-D tomography by a stereoscopy, allowing one to visualize the spatial configuration of the object under analysis. In this work, 2-D and 3-D radiographic images have been acquired using thermal neutrons and reactor-produced radioisotopes and proper imaging plates as detectors. The stereographic vision has been achieved by taking two radiographs of the same object at different angles, from the detector point of view. After a treatment to render them red-white and green-white they were properly merged to yield a single image capable to be watched with red-green glasses. All the image treatment and rendering has been performed with the software ImageJ. (author)

  18. Comparison of single-shot fast spin-echo sequence and T2-weighted fast spin-echo sequence in MR imaging of the brain

    International Nuclear Information System (INIS)

    Cha, Sung Ho; Seo, Jeong Jin; Jeong, Gwang Woo; Kim, Jae Kyu; Kim, Yun Hyeon; Jeong, Yong Yeon; Kang, Heoung Keun; Oh, Hee Yeon; Yoon, Jong Hoon

    1998-01-01

    The purpose of this study was to evaluate the usefulness of the single-shot fast spinecho (SS-FSE) sequence in comparison with the T2-weighted fast spin-echo (T2-FSE) sequence in brain MR imaging. In 41 patients aged 15-75 years with intracranial lesion, both SS-FSE and T2-FES images were obtained using a 1.5-T MR system. Lesions included cerebral ischemia or infarcts (n=3D23), tumors (n=3D10), hemorrhages (n=3D3), inflammatory diseases (n=3D2), arachnoid cysts(n=3D2), and vascular disease (n=3D1), and the MR images were retrospectively evaluated. To calculate contrast-to-noise ratio (CNR), percentage contrast, and signal-to-noise ratio (SNR)-and thus make a quantitative comparison-the mean signal intensities of lesions, normal brain tissue, and noise out-side the patient were measured. For qualitative comparison, the visibility, margin, and extent of the lesions were rated using a five-grade system, and the degree of MR artifacts was also evaluated. Wilcoxon's signed ranks test was used for statistical analysis. The mean CNR of lesions was significantly higher on SS-FSE (31.3) than on T2-FSE images (27.5) (p=3D0.0131). Mean percentage contrast was also higher on SS-FSE (159.0) than on T2-FSE images (108.5) (p=3D0.0222), but mean SNR was higher on T2-FSE (80.3) than on SS-FSE images (53.5) (p=3D0.0000). No significant differences in lesion visibility were observed between the two imaging sequences, though margin and extent of the lesion were worse on SS-FSE images. For MR artifacts, no significant differences were demonstrated. For the evaluation of most intracranial lesions, MR imaging using the SS-FSE sequence appears to be slightly inferior to the T2-FSE sequence, but may be useful where patients are ill or uncooperative, or where children require sedation.=20

  19. SPIO-enhanced MR imaging for HCC detection in cirrhotic patient : comparison of various techniques for optimal sequence selection

    International Nuclear Information System (INIS)

    Kim, In Hwan; Lee, Jeong Min; Kwak, Hyo Sung; Kim, Chong Soo; Yu, Hee Chul; Kim, Tae Kon; Lee Soo Tiek

    2000-01-01

    To compare the efficacy of breathhold and non-breathhold sequences in the detection of hepatocellular carcinoma (HCC) in cirrhotic patients using superparamagnetic iron oxide (SPIO)-enhanced MR imaging, and to determine the optimal sequence combination. By means of unenhanced and iron-oxide-enhanced MRI, 29 patients with 49 nodular HCCs were evaluated for the presence of HCC nodules. Twenty-one were male and eight were female, and their ages ranged from 38 to 71 (mean, 56) years. Eight different MR sequences were used, including four non-breath-hold sequences and four breath-hold, and images were obtained before and after the administration of SPIO particles. Non-breath-hold sequences included T2-, proton density-weighted SE, and TSE imaging, while breath-hold sequences comprised T1-weighted fast low-angle shot (T1w FLASH), half-Fourier acquisition single shot turbo spine echo (HASTE), T2-weighted fast imaging with steady-state free precession (T2 * wFISP) and T2-weighted breath-hold TSE (T2wBHTSE). Image analysis involved both quantitative and qualitative analysis. The quantitative parameters calculated were signal-to noise (S/N) ratios for livers and tumors, contrast to noise (C/N) ratios for tumors seen on precontrast and postcontrast images, and percentage of signal intensity loss (PSIL) after SPIO injection. Images were analysed qualitatively in terms of image artifacts and lesion conspicuity, and prior to calculating sensitivity, the number of lesions detected using various pulse sequences were counted. SPIO had a marked effect on liver S/N ratio but a minimal effect on tumor S/N ratio. PSIL was best in T2 * wFISP images, while T2wSE images showed the second-best results (p less than 0.05). Tumor-to-liver C/N values were also highest with T2 * wFISP, while T2wTSE and HASTE images were next. Qualitative study showed that non-breath hold images and FISP were better than breath hold images in terms of lesion conspicuity. The latter, however, were much better

  20. On the Usage of GPUs for Efficient Motion Estimation in Medical Image Sequences

    Directory of Open Access Journals (Sweden)

    Jeyarajan Thiyagalingam

    2011-01-01

    Full Text Available Images are ubiquitous in biomedical applications from basic research to clinical practice. With the rapid increase in resolution, dimensionality of the images and the need for real-time performance in many applications, computational requirements demand proper exploitation of multicore architectures. Towards this, GPU-specific implementations of image analysis algorithms are particularly promising. In this paper, we investigate the mapping of an enhanced motion estimation algorithm to novel GPU-specific architectures, the resulting challenges and benefits therein. Using a database of three-dimensional image sequences, we show that the mapping leads to substantial performance gains, up to a factor of 60, and can provide near-real-time experience. We also show how architectural peculiarities of these devices can be best exploited in the benefit of algorithms, most specifically for addressing the challenges related to their access patterns and different memory configurations. Finally, we evaluate the performance of the algorithm on three different GPU architectures and perform a comprehensive analysis of the results.

  1. Exploring the effects of gravity on tongue motion using ultrasound image sequences

    Science.gov (United States)

    Stone, Maureen; Crouse, Ulla; Sutton, Marty

    2002-05-01

    Our goal in the research was to explore the effect that gravity had on the vocal-tract system by using ultrasound data collected in the upright and supine positions. All potential subjects were given an ultrasound pretest to determine whether they could repeat a series of 3-4 words precise enough to allow an accurate series of images to be collected. Out of these potential subjects, approximately 5-7 subjects were eventually used in the research. The method of collecting ultrasound data required the immobilization of the patient by restraining their neck in a custom fitted neck restraint. The neck restraint held an ultrasound transducer positioned at a critical angle underneath the patients' lower jawbone, which served to reduce errors and increase image resolution. To accurately analyze the series of images collected from ultrasound imaging, the surfaces of the tongue were digitized and tongue motion was time-aligned across the upright and supine sequences. Comparisons between the upright and supine data were then made by using L2 norms to determine averages and differences regarding the behavior between the two positions. Curves and locations of the maximum and minimum differences will be discussed.

  2. A Low-Complexity Algorithm for Static Background Estimation from Cluttered Image Sequences in Surveillance Contexts

    Directory of Open Access Journals (Sweden)

    Reddy Vikas

    2011-01-01

    Full Text Available Abstract For the purposes of foreground estimation, the true background model is unavailable in many practical circumstances and needs to be estimated from cluttered image sequences. We propose a sequential technique for static background estimation in such conditions, with low computational and memory requirements. Image sequences are analysed on a block-by-block basis. For each block location a representative set is maintained which contains distinct blocks obtained along its temporal line. The background estimation is carried out in a Markov Random Field framework, where the optimal labelling solution is computed using iterated conditional modes. The clique potentials are computed based on the combined frequency response of the candidate block and its neighbourhood. It is assumed that the most appropriate block results in the smoothest response, indirectly enforcing the spatial continuity of structures within a scene. Experiments on real-life surveillance videos demonstrate that the proposed method obtains considerably better background estimates (both qualitatively and quantitatively than median filtering and the recently proposed "intervals of stable intensity" method. Further experiments on the Wallflower dataset suggest that the combination of the proposed method with a foreground segmentation algorithm results in improved foreground segmentation.

  3. Coseismic deformation pattern of the Emilia 2012 seismic sequence imaged by Radarsat-1 interferometry

    Directory of Open Access Journals (Sweden)

    Christian Bignami

    2012-10-01

    Full Text Available On May 20 and 29, 2012, two earthquakes of magnitudes 5.9 and 5.8 (Mw, respectively, and their aftershock sequences hit the central Po Plain (Italy, about 40 km north of Bologna. More than 2,000 sizable aftershocks were recorded by the Isti-tuto Nazionale di Geofisica e Vulcanologia (INGV; National Institute of Geophysics and Volcanology National Seismic Network (http://iside.rm.ingv.it/. The sequence was generated by pure compressional faulting over blind thrusts of the western Ferrara Arc, and it involved a 50-km-long stretch of this buried outer front of the northern Apennines. The focal mechanisms of the larger shocks agree with available structural data and with present-day tectonic stress indicators, which show locally a maximum horizontal stress oriented ca. N-S; i.e. oriented perpendicular to the main structural trends. Most of the sequence occurred between 1 km and 12 km in depth, above the local basal detachment of the outer thrust fronts of the northern Apennines. We measured the surface displacement patterns associated with the mainshocks and some of the larger aftershocks (some of which had Mw >5.0 by applying the Interferometric Synthetic Aperture Radar (InSAR technique to a pair of C-Band Radarsat-1 images. We then used the coseismic motions detected over the epicentral region as input information, to obtain the best-fit model fault for the two largest shocks. […

  4. A probabilistic cell model in background corrected image sequences for single cell analysis

    Directory of Open Access Journals (Sweden)

    Fieguth Paul

    2010-10-01

    Full Text Available Abstract Background Methods of manual cell localization and outlining are so onerous that automated tracking methods would seem mandatory for handling huge image sequences, nevertheless manual tracking is, astonishingly, still widely practiced in areas such as cell biology which are outside the influence of most image processing research. The goal of our research is to address this gap by developing automated methods of cell tracking, localization, and segmentation. Since even an optimal frame-to-frame association method cannot compensate and recover from poor detection, it is clear that the quality of cell tracking depends on the quality of cell detection within each frame. Methods Cell detection performs poorly where the background is not uniform and includes temporal illumination variations, spatial non-uniformities, and stationary objects such as well boundaries (which confine the cells under study. To improve cell detection, the signal to noise ratio of the input image can be increased via accurate background estimation. In this paper we investigate background estimation, for the purpose of cell detection. We propose a cell model and a method for background estimation, driven by the proposed cell model, such that well structure can be identified, and explicitly rejected, when estimating the background. Results The resulting background-removed images have fewer artifacts and allow cells to be localized and detected more reliably. The experimental results generated by applying the proposed method to different Hematopoietic Stem Cell (HSC image sequences are quite promising. Conclusion The understanding of cell behavior relies on precise information about the temporal dynamics and spatial distribution of cells. Such information may play a key role in disease research and regenerative medicine, so automated methods for observation and measurement of cells from microscopic images are in high demand. The proposed method in this paper is capable

  5. Diffusion-weighted imaging of the rat pelvis using 3D water-excitation MP-RAGE MR sequence

    International Nuclear Information System (INIS)

    Numano, Tomokazu; Homma, Kazuhiro; Hyodo, Koji; Nitta, Naotaka; Iwasaki, Nobuaki

    2008-01-01

    We developed a novel technique for fat-saturated, 3-dimensional (3D) diffusion-weighted (DW) magnetic resonance (MR) imaging sequencing based upon the 3D magnetization-prepared, rapid gradient-echo (3D-MP-RAGE) method. We saturated fat using 2 techniques, chemical shift selective (CHESS; FatSat)-3D-DWI sequence versus water excitation (WE)-3D-DWI method, then compared the 2 sequences in terms of degree of fat suppression. In preparing the FatSat-3D-DWI sequence, we used a ''CHESS-90deg radiofrequency (RF)-motion probing gradient (MPG)-180deg RFMPG-90deg RF'' pulse-train, to sensitize the magnetization to fat-saturated diffusion. In contrast, in the WE-3D-DWI sequence, we selected a RAGE-excitation pulse with a binominal-pulse 1-1 or 1-2-1 for water-excited (fat-saturated) diffusion imaging. Experimental results in a phantom confirmed the effects of diffusion weighting and of fat saturation. Fat saturation was much better in the WE-3D-DWI sequence than the CHESS-3D-DWI sequence. From results from animal (rat pelvis) experiments using WE-3D-DWI, we obtained fat-saturated DWI. This sequence was useful for in vivo imaging. (author)

  6. Generalized min-max bound-based MRI pulse sequence design framework for wide-range T1 relaxometry: A case study on the tissue specific imaging sequence.

    Directory of Open Access Journals (Sweden)

    Yang Liu

    Full Text Available This paper proposes a new design strategy for optimizing MRI pulse sequences for T1 relaxometry. The design strategy optimizes the pulse sequence parameters to minimize the maximum variance of unbiased T1 estimates over a range of T1 values using the Cramér-Rao bound. In contrast to prior sequences optimized for a single nominal T1 value, the optimized sequence using our bound-based strategy achieves improved precision and accuracy for a broad range of T1 estimates within a clinically feasible scan time. The optimization combines the downhill simplex method with a simulated annealing process. To show the effectiveness of the proposed strategy, we optimize the tissue specific imaging (TSI sequence. Preliminary Monte Carlo simulations demonstrate that the optimized TSI sequence yields improved precision and accuracy over the popular driven-equilibrium single-pulse observation of T1 (DESPOT1 approach for normal brain tissues (estimated T1 700-2000 ms at 3.0T. The relative mean estimation error (MSE for T1 estimation is less than 1.7% using the optimized TSI sequence, as opposed to less than 7.0% using DESPOT1 for normal brain tissues. The optimized TSI sequence achieves good stability by keeping the MSE under 7.0% over larger T1 values corresponding to different lesion tissues and the cerebrospinal fluid (up to 5000 ms. The T1 estimation accuracy using the new pulse sequence also shows improvement, which is more pronounced in low SNR scenarios.

  7. Research on the Compression Algorithm of the Infrared Thermal Image Sequence Based on Differential Evolution and Double Exponential Decay Model

    Science.gov (United States)

    Zhang, Jin-Yu; Meng, Xiang-Bing; Xu, Wei; Zhang, Wei; Zhang, Yong

    2014-01-01

    This paper has proposed a new thermal wave image sequence compression algorithm by combining double exponential decay fitting model and differential evolution algorithm. This study benchmarked fitting compression results and precision of the proposed method was benchmarked to that of the traditional methods via experiment; it investigated the fitting compression performance under the long time series and improved model and validated the algorithm by practical thermal image sequence compression and reconstruction. The results show that the proposed algorithm is a fast and highly precise infrared image data processing method. PMID:24696649

  8. Research on the Compression Algorithm of the Infrared Thermal Image Sequence Based on Differential Evolution and Double Exponential Decay Model

    Directory of Open Access Journals (Sweden)

    Jin-Yu Zhang

    2014-01-01

    Full Text Available This paper has proposed a new thermal wave image sequence compression algorithm by combining double exponential decay fitting model and differential evolution algorithm. This study benchmarked fitting compression results and precision of the proposed method was benchmarked to that of the traditional methods via experiment; it investigated the fitting compression performance under the long time series and improved model and validated the algorithm by practical thermal image sequence compression and reconstruction. The results show that the proposed algorithm is a fast and highly precise infrared image data processing method.

  9. The role of high-resolution computed tomography (HRCT) and magnetic resonance imaging (MRI) in the diagnosis of preoperative and postoperative complications caused by acquired cholesteatomas; CT und MRT des erworbenen Cholesteatoms: Prae- und postoperative Bildgebung

    Energy Technology Data Exchange (ETDEWEB)

    Krestan, C.; Czerny, C. [Abteilung fuer Osteologie, Univ.-Klinik fuer Radiodiagnostik, Wien (Austria); Gstoettner, W. [Univ.-Klinik fuer Hals-Nasen-Ohren-Heilkunde, Frankfurt (Germany); Franz, P. [Univ.-Klinik fuer Hals-Nasen-Ohren-Heilkunde, Wien (Austria)

    2003-03-01

    The role of high-resolution computed tomography (HRCT) and magnetic resonance imaging (MRI) in the diagnosis of preoperative and postoperative complications caused by acquired cholesteatomas will be described in this paper. The pre- and postoperative imaging of the temporal bone was performed with HRCT and MRI. HRCT and MRI were performed in the axial and coronal plane. MRI was done with T2 weighted and T1 weighted sequences both before and after the intravenous application of contrast material. All imaging findings were confirmed clinically or surgically. The preoperative cholesteatoma-caused complications depicted by HRCT included bony erosions of the ossicles, scutum, facial canal in the middle ear, tympanic walls including the tegmen tympani, and of the labyrinth. The preoperative cholesteatoma-caused complications depicted by MRI included signs indicative for labyrinthitis, and brain abscess. Postoperative HRCT depicted bony erosions caused by recurrent cholesteatoma, bony defects of the facial nerve and of the labyrinth, and a defect of the tegmen tympani with a soft tissue mass in the middle ear. Postoperative MRI delineated neuritis of the facial nerve, labyrinthitis, and a meningo-encephalocele protruding into the middle ear. HRCT and MRI are excellent imaging tools to depict either bony or soft tissue complications or both if caused by acquired cholesteatomas. According to our findings and to the literature HRCT and MRI are complementary imaging methods to depict pre- or postoperative complications of acquired cholesteatomas if these are suspected by clinical examination. (orig.) [German] In dieser Arbeit wird die Rolle der hochaufloesenden Computertomographie (HRCT) und der Magnetresonanztomographie (MRT) zur Abklaerung prae- und postoperativ bedingter Komplikationen erworbener Cholesteatome beschrieben. Die Bildgebung wurde sowohl mit der HRCT als auch mit der MRT durchgefuehrt. Die HRCT und die MRT wurden in axialer und koronaler Ebene (auch

  10. Evaluation of an accelerated 3D SPACE sequence with compressed sensing and free-stop scan mode for imaging of the knee.

    Science.gov (United States)

    Henninger, B; Raithel, E; Kranewitter, C; Steurer, M; Jaschke, W; Kremser, C

    2018-05-01

    To prospectively evaluate a prototypical 3D turbo-spin-echo proton-density-weighted sequence with compressed sensing and free-stop scan mode for preventing motion artefacts (3D-PD-CS-SPACE free-stop) for knee imaging in a clinical setting. 80 patients underwent 3T magnetic resonance imaging (MRI) of the knee with our 2D routine protocol and with 3D-PD-CS-SPACE free-stop. In case of a scan-stop caused by motion (images are calculated nevertheless) the sequence was repeated without free-stop mode. All scans were evaluated by 2 radiologists concerning image quality of the 3D-PD-CS-SPACE (with and without free-stop). Important knee structures were further assessed in a lesion based analysis and compared to our reference 2D-PD-fs sequences. Image quality of the 3D-PD-CS-SPACE free-stop was found optimal in 47/80, slightly compromised in 21/80, moderately in 10/80 and severely in 2/80. In 29/80, the free-stop scan mode stopped the 3D-PD-CS-SPACE due to subject motion with a slight increase of image quality at longer effective acquisition times. Compared to the 3D-PD-CS-SPACE with free-stop, the image quality of the acquired 3D-PD-CS-SPACE without free-stop was found equal in 6/29, slightly improved in 13/29, improved with equal contours in 8/29, and improved with sharper contours in 2/29. The lesion based analysis showed a high agreement between the results from the 3D-PD-CS-SPACE free-stop and our 2D-PD-fs routine protocol (overall agreement 96.25%-100%, Cohen's Kappa 0.883-1, p SPACE free-stop is a reliable alternative for standard 2D-PD-fs protocols with acceptable acquisition times. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Detection of hepatic VX2 carcinomas with ferucarbotran-enhanced magnetic resonance imaging in rabbits: Comparison of nine pulse sequences

    International Nuclear Information System (INIS)

    Kim, Seong Hyun; Choi, Dongil; Lim, Hyo K.; Kim, Min Ju; Jang, Kyung Mi; Kim, Seung Hoon; Lee, Won Jae; Lee, Jongmee; Jeon, Yong Hwan; Lim, Jae Hoon

    2006-01-01

    Objective: To compare the diagnostic performance of a variety of magnetic resonance imaging (MRI) sequences, in order to identify the most effective ferucarbotran-enhanced sequence for the detection of multiple small hepatic VX2 carcinomas in rabbits. Methods: Fifteen rabbits with experimentally induced 135 VX2 carcinomas in the liver underwent ferucarbotran-enhanced MRI using the following nine pulse sequences: a fat-suppressed fast spin-echo (FSE) sequence with two echo times (TE) (proton density- and T2-weighted images), four different T2*-weighted fast multiplanar GRASS (gradient-recalled acquisition in the steady state) (FMPGR) with the combination of three TEs (9, 12, 15 ms, respectively) and two flip angles (20 deg., 80 deg., respectively), T2*-weighted fast multiplanar spoiled GRASS (FMPSPGR), T1-weighted FMPSPGR, and dynamic T1-weighted FMPSPGR. All images were reviewed by three radiologists with quantitative and qualitative analysis. Results: Tumor-to-liver contrast-to-noise ratio of the proton density-weighted FSE sequence was significantly higher than those of the others (p o ) images were superior to those of the others and for the detection of very small hepatic tumors of less than 5 mm, the sensitivities of these sequences were less than 30%. Conclusion: Ferucarbotran-enhanced T2- and proton density-weighted FSE and T2*-weighed FMPGR (TE/flip angle, 12/20 o ) images were found to be the most effective pulse sequences for the detection of multiple small hepatic VX2 carcinomas but these sequences were limited in the detection of very small hepatic tumors of less than 5 mm in size

  12. [Contrastive analysis of artifacts produced by metal dental crowns in 3.0 T magnetic resonance imaging with six sequences].

    Science.gov (United States)

    Lan, Gao; Yunmin, Lian; Pu, Wang; Haili, Huai

    2016-06-01

    This study aimed to observe and evaluate six 3.0 T sequences of metallic artifacts produced by metal dental crowns. Dental crowns fabricated with four different materials (Co-Gr, Ni-Gr, Ti alloy and pure Ti) were evaluated. A mature crossbreed dog was used as the experimental animal, and crowns were fabricated for its upper right second premolar. Each crown was examined through head MRI (3.0 T) with six sequences, namely, T₁ weighted-imaging of spin echo (T₁W/SE), T₂ weighted-imaging of inversion recovery (T₂W/IR), T₂ star gradient echo (T₂*/GRE), T2 weighted-imaging of fast spin echo (T₂W/FSE), T₁ weighted-imaging of fluid attenuate inversion recovery (T₂W/FLAIR), and T₂ weighted-imaging of propeller (T₂W/PROP). The largest area and layers of artifacts were assessed and compared. The artifact in the T₂*/GRE sequence was significantly wider than those in the other sequences (P 0.05). T₂*/GRE exhibit the strongest influence on the artifact, whereas the five other sequences contribute equally to artifact generation.

  13. Cartilage volume quantification with multi echo data image combination sequence in swine knee at 3.0 T MRI

    International Nuclear Information System (INIS)

    Zhang Lirong; Wang Dongqing; Wei Chuanshe; Ma Cong; Wang Dehang

    2010-01-01

    Objective: To investigate the accuracy and reproducibility of multi echo data imagine combination (MEDIC) sequence with water excitation at 3.0 T in swine knee cartilage. Methods: Sagittal MEDIC sequences (0.6 mm slice thickness, isotropic) were acquired twice at 3.0 T MRI in 30 swine knees. The knee cartilage was then removed and the volume was directly measured with water substitution method. The cartilage volume was also determined with a validated open source image software OsiriX by two observers (A and B). The cartilage volumes obtained by two methods were compared. The reproducibility of MEDIC for quantitative measurement was accessed by the root-mean-square (RMS) of variation coefficient. Interobserver and intraobserver precision errors were compared using a paired students t-test. The accuracy of MEDIC for quantitative measurement was determined by the random pairwise differences, systematic pairwise differences and the Pearson, correlation coefficients. Time of semiautomatic and manual segmentation were recorded. Results: Time was saved about 75% by using semiautomatic segmentation methods [(4.0± 1.5) min] versus manual segmentation [(16.0±0.9) min]. Interobserver precision errors (RMS CV% for paired analysis) between A and B for cartilage volume measurement were (2.66±0.82) ml and(2.61± 0.81) ml, t=0.24, P=0.81 (patella); (2.40±0.69) ml and (2.49±0.85) ml, t=-0.45, P=0.65 (medial femoral condyle); (2.28±0.74) ml and(2.41±0.78) ml, t=-0.66, P=0.51 (lateral femoral condyle); (3.43±1.28) ml and (3.51±1.08) ml, t=-0.26, P=0.79 (femora trochlea) with sagittal MEDIC. Intraobserver precision errors (RMS CV% for paired analysis) of observer A for the first and second cartilage volume measurement were (2.64±0.62) ml and (2.67±0.60) ml, t=-0.19, P=0.85 (patella); (2.43±0.60) ml and (2.39±0.59) ml, t=0.26, P=0.80 (medial femoral condyle); (2.26±0.56) ml and (2.30±0.57) ml, t=-0.27, P=0.78 (lateral femoral condyle); (3.40± 1.20) ml and (3.47±1

  14. Evaluation of Magnetic Resonance Imaging-Compatible Needles and Interactive Sequences for Musculoskeletal Interventions Using an Open High-Field Magnetic Resonance Imaging Scanner

    International Nuclear Information System (INIS)

    Wonneberger, Uta; Schnackenburg, Bernhard; Streitparth, Florian; Walter, Thula; Rump, Jens; Teichgraeber, Ulf K. M.

    2010-01-01

    In this article, we study in vitro evaluation of needle artefacts and image quality for musculoskeletal laser-interventions in an open high-field magnetic resonance imaging (MRI) scanner at 1.0T with vertical field orientation. Five commercially available MRI-compatible puncture needles were assessed based on artefact characteristics in a CuSO4 phantom (0.1%) and in human cadaveric lumbar spines. First, six different interventional sequences were evaluated with varying needle orientation to the main magnetic field B0 (0 o to 90 o ) in a sequence test. Artefact width, needle-tip error, and contrast-to-noise ratio (CNR) were calculated. Second, a gradient-echo sequence used for thermometric monitoring was assessed and in varying echo times, artefact width, tip error, and signal-to-noise ratio (SNR) were measured. Artefact width and needle-tip error correlated with needle material, instrument orientation to B0, and sequence type. Fast spin-echo sequences produced the smallest needle artefacts for all needles, except for the carbon fibre needle (width o to B0. Overall, the proton density-weighted spin-echo sequences had the best CNR (CNR Muscle/Needle >16.8). Concerning the thermometric gradient echo sequence, artefacts remained <5 mm, and the SNR reached its maximum at an echo time of 15 ms. If needle materials and sequences are accordingly combined, guidance and monitoring of musculoskeletal laser interventions may be feasible in a vertical magnetic field at 1.0T.

  15. Optic disc boundary segmentation from diffeomorphic demons registration of monocular fundus image sequences versus 3D visualization of stereo fundus image pairs for automated early stage glaucoma assessment

    Science.gov (United States)

    Gatti, Vijay; Hill, Jason; Mitra, Sunanda; Nutter, Brian

    2014-03-01

    Despite the current availability in resource-rich regions of advanced technologies in scanning and 3-D imaging in current ophthalmology practice, world-wide screening tests for early detection and progression of glaucoma still consist of a variety of simple tools, including fundus image-based parameters such as CDR (cup to disc diameter ratio) and CAR (cup to disc area ratio), especially in resource -poor regions. Reliable automated computation of the relevant parameters from fundus image sequences requires robust non-rigid registration and segmentation techniques. Recent research work demonstrated that proper non-rigid registration of multi-view monocular fundus image sequences could result in acceptable segmentation of cup boundaries for automated computation of CAR and CDR. This research work introduces a composite diffeomorphic demons registration algorithm for segmentation of cup boundaries from a sequence of monocular images and compares the resulting CAR and CDR values with those computed manually by experts and from 3-D visualization of stereo pairs. Our preliminary results show that the automated computation of CDR and CAR from composite diffeomorphic segmentation of monocular image sequences yield values comparable with those from the other two techniques and thus may provide global healthcare with a cost-effective yet accurate tool for management of glaucoma in its early stage.

  16. Robust Small Target Co-Detection from Airborne Infrared Image Sequences.

    Science.gov (United States)

    Gao, Jingli; Wen, Chenglin; Liu, Meiqin

    2017-09-29

    In this paper, a novel infrared target co-detection model combining the self-correlation features of backgrounds and the commonality features of targets in the spatio-temporal domain is proposed to detect small targets in a sequence of infrared images with complex backgrounds. Firstly, a dense target extraction model based on nonlinear weights is proposed, which can better suppress background of images and enhance small targets than weights of singular values. Secondly, a sparse target extraction model based on entry-wise weighted robust principal component analysis is proposed. The entry-wise weight adaptively incorporates structural prior in terms of local weighted entropy, thus, it can extract real targets accurately and suppress background clutters efficiently. Finally, the commonality of targets in the spatio-temporal domain are used to construct target refinement model for false alarms suppression and target confirmation. Since real targets could appear in both of the dense and sparse reconstruction maps of a single frame, and form trajectories after tracklet association of consecutive frames, the location correlation of the dense and sparse reconstruction maps for a single frame and tracklet association of the location correlation maps for successive frames have strong ability to discriminate between small targets and background clutters. Experimental results demonstrate that the proposed small target co-detection method can not only suppress background clutters effectively, but also detect targets accurately even if with target-like interference.

  17. The induced earthquake sequence related to the St. Gallen deep geothermal project (Switzerland): Fault reactivation and fluid interactions imaged by microseismicity

    Science.gov (United States)

    Diehl, T.; Kraft, T.; Kissling, E.; Wiemer, S.

    2017-09-01

    In July 2013, a sequence of more than 340 earthquakes was induced by reservoir stimulations and well-control procedures following a gas kick at a deep geothermal drilling project close to the city of St. Gallen, Switzerland. The sequence culminated in an ML 3.5 earthquake, which was felt within 10-15 km from the epicenter. High-quality earthquake locations and 3-D reflection seismic data acquired in the St. Gallen project provide a unique data set, which allows high-resolution studies of earthquake triggering related to the injection of fluids into macroscopic fault zones. In this study, we present a high-precision earthquake catalog of the induced sequence. Absolute locations are constrained by a coupled hypocenter-velocity inversion, and subsequent double-difference relocations image the geometry of the ML 3.5 rupture and resolve the spatiotemporal evolution of seismicity. A joint interpretation of earthquake and seismic data shows that the majority of the seismicity occurred in the pre-Mesozoic basement, hundreds of meters below the borehole and the targeted Mesozoic sequence. We propose a hydraulic connectivity between the reactivated fault and the borehole, likely through faults mapped by seismic data. Despite the excellent quality of the seismic data, the association of seismicity with mapped faults remains ambiguous. In summary, our results document that the actual hydraulic properties of a fault system and hydraulic connections between its fault segments are complex and may not be predictable upfront. Incomplete knowledge of fault structures and stress heterogeneities within highly complex fault systems additionally challenge the degree of predictability of induced seismicity related to underground fluid injections.

  18. The Optimization of Magnetic Resonance Imaging Pulse Sequences in Order to Better Detection of Multiple Sclerosis Plaques.

    Science.gov (United States)

    Farshidfar, Z; Faeghi, F; Haghighatkhah, H R; Abdolmohammadi, J

    2017-09-01

    Magnetic resonance imaging (MRI) is the most sensitive technique to detect multiple sclerosis (MS) plaques in central nervous system. In some cases, the patients who were suspected to MS, Whereas MRI images are normal, but whether patients don't have MS plaques or MRI images are not enough optimized enough in order to show MS plaques? The aim of the current study is evaluating the efficiency of different MRI sequences in order to better detection of MS plaques. In this cross-sectional study which was performed at Shohada-E Tajrish in Tehran - Iran hospital between October, 2011 to April, 2012, included 20 patients who suspected to MS disease were selected by the method of random sampling and underwent routine brain Pulse sequences (Axial T2w, Axial T1w, Coronal T2w, Sagittal T1w, Axial FLAIR) by Siemens, Avanto, 1.5 Tesla system. If any lesion which is suspected to the MS disease was observed, additional sequences such as: Sagittal FLAIR Fat Sat, Sagittal PDw-fat Sat, Sagittal PDw-water sat was also performed. This study was performed in about 52 lesions and the results in more than 19 lesions showed that, for the Subcortical and Infratentorial areas, PDWw sequence with fat suppression is the best choice, And in nearly 33 plaques located in Periventricular area, FLAIR Fat Sat was the most effective sequence than both PDw fat and water suppression pulse sequences. Although large plaques may visible in all images, but important problem in patients with suspected MS is screening the tiny MS plaques. This study showed that for revealing the MS plaques located in the Subcortical and Infratentorial areas, PDw-fat sat is the most effective sequence, and for MS plaques in the periventricular area, FLAIR fat Sat is the best choice.

  19. SWI or T2*: which MRI sequence to use in the detection of cerebral microbleeds? The Karolinska Imaging Dementia Study.

    Science.gov (United States)

    Shams, S; Martola, J; Cavallin, L; Granberg, T; Shams, M; Aspelin, P; Wahlund, L O; Kristoffersen-Wiberg, M

    2015-06-01

    Cerebral microbleeds are thought to have potentially important clinical implications in dementia and stroke. However, the use of both T2* and SWI MR imaging sequences for microbleed detection has complicated the cross-comparison of study results. We aimed to determine the impact of microbleed sequences on microbleed detection and associated clinical parameters. Patients from our memory clinic (n = 246; 53% female; mean age, 62) prospectively underwent 3T MR imaging, with conventional thick-section T2*, thick-section SWI, and conventional thin-section SWI. Microbleeds were assessed separately on thick-section SWI, thin-section SWI, and T2* by 3 raters, with varying neuroradiologic experience. Clinical and radiologic parameters from the dementia investigation were analyzed in association with the number of microbleeds in negative binomial regression analyses. Prevalence and number of microbleeds were higher on thick-/thin-section SWI (20/21%) compared with T2*(17%). There was no difference in microbleed prevalence/number between thick- and thin-section SWI. Interrater agreement was excellent for all raters and sequences. Univariate comparisons of clinical parameters between patients with and without microbleeds yielded no difference across sequences. In the regression analysis, only minor differences in clinical associations with the number of microbleeds were noted across sequences. Due to the increased detection of microbleeds, we recommend SWI as the sequence of choice in microbleed detection. Microbleeds and their association with clinical parameters are robust to the effects of varying MR imaging sequences, suggesting that comparison of results across studies is possible, despite differing microbleed sequences. © 2015 by American Journal of Neuroradiology.

  20. Magnetic resonance imaging (MRI) of articular cartilage of the knee using ultrashort echo time (uTE) sequences with spiral acquisition

    International Nuclear Information System (INIS)

    Goto, Hajimu; Fujii, Masahiko; Iwama, Yuki; Aoyama, Nobukazu; Ohno, Yoshiharu; Sugimura, Kazuro

    2012-01-01

    The objective of this study was to evaluate the sensitivity of ultrashort echo time (uTE) sequence for visualisation of calcified deep layers of articular cartilage. MRI with a uTE sequence was performed on five healthy volunteers. Signals from the calcified deep layers of the articular knee cartilage were evaluated on uTE subtraction images and computed tomography images. The calcified deep layers of the articular cartilage changed from having a low to a high signal when imaged with a uTE sequence. The reported uTE sequence was effective in imaging the deep layers of the knee cartilage.

  1. Estimation of the Above Ground Biomass of Tropical Forests using Polarimetric and Tomographic SAR Data Acquired at P Band and 3-D Imaging Techniques

    Science.gov (United States)

    Ferro-Famil, L.; El Hajj Chehade, B.; Ho Tong Minh, D.; Tebaldini, S.; LE Toan, T.

    2016-12-01

    Developing and improving methods to monitor forest biomass in space and time is a timely challenge, especially for tropical forests, for which SAR imaging at larger wavelength presents an interesting potential. Nevertheless, directly estimating tropical forest biomass from classical 2-D SAR images may reveal a very complex and ill-conditioned problem, since a SAR echo is composed of numerous contributions, whose features and importance depend on many geophysical parameters, such has ground humidity, roughness, topography… that are not related to biomass. Recent studies showed that SAR modes of diversity, i.e. polarimetric intensity ratios or interferometric phase centers, do not fully resolve this under-determined problem, whereas Pol-InSAR tree height estimates may be related to biomass through allometric relationships, with, in general over tropical forests, significant levels of uncertainty and lack of robustness. In this context, 3-D imaging using SAR tomography represents an appealing solution at larger wavelengths, for which wave penetration properties ensures a high quality mapping of a tropical forest reflectivity in the vertical direction. This paper presents a series of studies led, in the frame of the preparation of the next ESA mission BIOMASS, on the estimation of biomass over a tropical forest in French Guiana, using Polarimetric SAR Tomographic (Pol-TomSAR) data acquired at P band by ONERA. It is then shown that Pol-TomoSAR significantly improves the retrieval of forest above ground biomass (AGB) in a high biomass forest (200 up to 500 t/ha), with an error of only 10% at 1.5-ha resolution using a reflectivity estimates sampled at a predetermined elevation. The robustness of this technique is tested by applying the same approach over another site, and results show a similar relationship between AGB and tomographic reflectivity over both sites. The excellent ability of Pol-TomSAR to retrieve both canopy top heights and ground topography with an error

  2. An objective method to optimize the MR sequence set for plaque classification in carotid vessel wall images using automated image segmentation.

    Directory of Open Access Journals (Sweden)

    Ronald van 't Klooster

    Full Text Available A typical MR imaging protocol to study the status of atherosclerosis in the carotid artery consists of the application of multiple MR sequences. Since scanner time is limited, a balance has to be reached between the duration of the applied MR protocol and the quantity and quality of the resulting images which are needed to assess the disease. In this study an objective method to optimize the MR sequence set for classification of soft plaque in vessel wall images of the carotid artery using automated image segmentation was developed. The automated method employs statistical pattern recognition techniques and was developed based on an extensive set of MR contrast weightings and corresponding manual segmentations of the vessel wall and soft plaque components, which were validated by histological sections. Evaluation of the results from nine contrast weightings showed the tradeoff between scan duration and automated image segmentation performance. For our dataset the best segmentation performance was achieved by selecting five contrast weightings. Similar performance was achieved with a set of three contrast weightings, which resulted in a reduction of scan time by more than 60%. The presented approach can help others to optimize MR imaging protocols by investigating the tradeoff between scan duration and automated image segmentation performance possibly leading to shorter scanning times and better image interpretation. This approach can potentially also be applied to other research fields focusing on different diseases and anatomical regions.

  3. New MR pulse sequence

    International Nuclear Information System (INIS)

    Harms, S.E.; Flamig, D.P.; Griffey, R.H.

    1990-01-01

    This paper describes a method for fat suppression for three-dimensional MR imaging. The FATS (fat-suppressed acquisition with echo time shortened) sequence employs a pair of opposing adiabatic half-passage RF pulses tuned on fat resonance. The imaging parameters are as follows: TR, 20 msec; TE, 21.7-3.2 msec; 1,024 x 128 x 128 acquired matrix; imaging time, approximately 11 minutes. A series of 54 examinations were performed. Excellent fat suppression with water excitation is achieved in all cases. The orbital images demonstrate superior resolution of small orbital lesions. The high signal-to-noise ratio (SNR) in cranial studies demonstrates excellent petrous bone and internal auditory canal anatomy

  4. Comparison of T1rho imaging between spoiled gradient echo (SPGR) and balanced steady state free precession (b-FFE) sequence of knee cartilage at 3 T MRI

    Energy Technology Data Exchange (ETDEWEB)

    Nozaki, Taiki; Kaneko, Yasuhito; Yu, Hon J. [Department of Radiological Sciences, University of California, Irvine, CA (United States); Kaneshiro, Kayleigh [School of Medicine, University of California, Irvine, CA (United States); Schwarzkopf, Ran [Department of Orthopaedic Surgery, University of California, Irvine, CA (United States); Yoshioka, Hiroshi, E-mail: hiroshi@uci.edu [Department of Radiological Sciences, University of California, Irvine, CA (United States)

    2015-07-15

    Highlights: • T1rho values on b-FFE tend to be higher than those on SPGR. • The reproducibility of T1rho cartilage segmentation is higher on SPGR than b-FFE. • There is angular variation of T1rho profiles. • Average T1rho values in the superficial layer are higher than in the deep layer. - Abstract: Purpose: To investigate the difference in T1rho profiles of the entire femoral cartilage between SPGR and b-FFE sequences at 3.0 T. Materials and methods: 20 healthy volunteers were enrolled in this study. T1rho images of each subject were acquired with two types of pulse sequences: SPGR and b-FFE. Femoral cartilage segmentation was performed by two independent raters slice-by-slice using Matlab. Inter- and intra-observer reproducibility between the two imaging protocols was calculated. The relative signal intensity (SI) of cartilage, subchondral bone marrow, joint effusion, and the relative signal contrast between structures of the knee were quantitatively measured. The difference in T1rho values between SPGR and b-FFE sequences was statistically analyzed using the Wilcoxon signed-rank test. Results: The average T1rho value of the entire femoral cartilage with b-FFE was significantly higher compared to SPGR (p < 0.05). The reproducibility of the segmented area and T1rho values was superior with SPGR compared to b-FFE. The inter-class correlation coefficient was 0.846 on SPGR and 0.824 on b-FFE. The intra-class correlation coefficient of T1rho values was 0.878 on SPGR and 0.836 on b-FFE. The two imaging techniques demonstrated different signal and contrast characteristics. The relative SI of fluid was significantly higher on SPGR, while the relative SI of subchondral bone was significantly higher on b-FFE (p < 0.001). There were also significant differences in the relative contrast between fluid–cartilage, fluid–subchondral bone, and cartilage–subchondral bone between the two sequences (all p < 0.001). Conclusion: We need to pay attention to differences in

  5. MR imaging at 0.5 Tesla with FLAIR sequence in the diagnosis of acute subarachnoid hemorrhage

    International Nuclear Information System (INIS)

    Kopsa, W.; Leitner, H.; Tscholakoff, D.; Perneczky, G.

    1998-01-01

    Purpose: Evaluation of MR imaging in patients with acute subarachnoid hemorrhage (SAH) at 0.5 Tesla using the FLAIR (Fluid Attenuated Inversion Recovery) sequenze. Additionally, the value of MR angiographie (MRA) in the diagnosis of intracranial aneurysms was assessed. Materials and Methods: 19 patients with suspected acute SAH were included in this study. MR imaging was performed using an axial FLAIR sequence and axial T 1 , T 2 and PD weighted sequences. In 16 patients an additional MRA (3D-TOF) was performed. 10 patients without SAH were examined as a control group. At the end of the study the 29 MR examinations were randomised and the images were read by two experienced radiologists; subsequently a consensus interpretation was made. Results: In 16 patients an acute SAH was verified with the FLAIR sequence, in 13 cases the origin of hemorrhage was found during surgery. In the consensus interpretation of the MR images all cases were diagnosed properly. 12 of the 16 MRA studies were of diagnostic quality, but only 6 cases were interpreted correctly. Conclusion: The FLAIR sequence at 0.5 Tesla proved effective in the diagnosis of acute SAH. MRA at 0.5 Tesla failed in the detection of intracranial aneurysms. (orig.) [de

  6. The estimation of geometry and motion of a surface from image sequences by means of linearisation of a paramatric model

    NARCIS (Netherlands)

    Korsten, Maarten J.; Houkes, Z.

    1990-01-01

    A method is given to estimate the geometry and motion of a moving body surface from image sequences. To this aim a parametric model of the surface is used, in order to reformulate the problem to one of parameter estimation. After linearization of the model standard linear estimation methods can be

  7. MR imaging of articular cartilage in the knee. Evaluation of cadaver knee by 3D FLASH sequence with fat saturation

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Katsuhiko; Hachiya, Junichi; Matsumura, Joji [Kyorin Univ., Mitaka, Tokyo (Japan). School of Medicine

    1999-06-01

    MR imaging of the articular cartilage of the 24 cadever knees was performed using 3D FLASH sequence with fat saturation. Good correlation was noted between MR findings and either macroscopic or microscopic appearances of the hyaline cartilage. Low signal intensity area without significant thinning of the cartilage was considered to represent the degenerative changes due to relatively early process of osteoarthritis. (author)

  8. Batch-processing of imaging or liquid-chromatography mass spectrometry datasets and De Novo sequencing of polyketide siderophores

    Czech Academy of Sciences Publication Activity Database

    Novák, Jiří; Sokolová, Lucie; Lemr, Karel; Pluháček, Tomáš; Palyzová, Andrea; Havlíček, Vladimír

    2017-01-01

    Roč. 1865, č. 7 (2017), s. 768-775 ISSN 1570-9639 R&D Projects: GA ČR(CZ) GA16-20229S; GA MŠk(CZ) LO1509 Institutional support: RVO:61388971 Keywords : Mass spectrometry imaging * De novo sequencing * Siderophores Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 2.773, year: 2016

  9. A FAST SEGMENTATION ALGORITHM FOR C-V MODEL BASED ON EXPONENTIAL IMAGE SEQUENCE GENERATION

    Directory of Open Access Journals (Sweden)

    J. Hu

    2017-09-01

    Full Text Available For the island coastline segmentation, a fast segmentation algorithm for C-V model method based on exponential image sequence generation is proposed in this paper. The exponential multi-scale C-V model with level set inheritance and boundary inheritance is developed. The main research contributions are as follows: 1 the problems of the "holes" and "gaps" are solved when extraction coastline through the small scale shrinkage, low-pass filtering and area sorting of region. 2 the initial value of SDF (Signal Distance Function and the level set are given by Otsu segmentation based on the difference of reflection SAR on land and sea, which are finely close to the coastline. 3 the computational complexity of continuous transition are successfully reduced between the different scales by the SDF and of level set inheritance. Experiment results show that the method accelerates the acquisition of initial level set formation, shortens the time of the extraction of coastline, at the same time, removes the non-coastline body part and improves the identification precision of the main body coastline, which automates the process of coastline segmentation.

  10. a Fast Segmentation Algorithm for C-V Model Based on Exponential Image Sequence Generation

    Science.gov (United States)

    Hu, J.; Lu, L.; Xu, J.; Zhang, J.

    2017-09-01

    For the island coastline segmentation, a fast segmentation algorithm for C-V model method based on exponential image sequence generation is proposed in this paper. The exponential multi-scale C-V model with level set inheritance and boundary inheritance is developed. The main research contributions are as follows: 1) the problems of the "holes" and "gaps" are solved when extraction coastline through the small scale shrinkage, low-pass filtering and area sorting of region. 2) the initial value of SDF (Signal Distance Function) and the level set are given by Otsu segmentation based on the difference of reflection SAR on land and sea, which are finely close to the coastline. 3) the computational complexity of continuous transition are successfully reduced between the different scales by the SDF and of level set inheritance. Experiment results show that the method accelerates the acquisition of initial level set formation, shortens the time of the extraction of coastline, at the same time, removes the non-coastline body part and improves the identification precision of the main body coastline, which automates the process of coastline segmentation.

  11. INTEGRATED GEOREFERENCING OF STEREO IMAGE SEQUENCES CAPTURED WITH A STEREOVISION MOBILE MAPPING SYSTEM – APPROACHES AND PRACTICAL RESULTS

    Directory of Open Access Journals (Sweden)

    H. Eugster

    2012-07-01

    Full Text Available Stereovision based mobile mapping systems enable the efficient capturing of directly georeferenced stereo pairs. With today's camera and onboard storage technologies imagery can be captured at high data rates resulting in dense stereo sequences. These georeferenced stereo sequences provide a highly detailed and accurate digital representation of the roadside environment which builds the foundation for a wide range of 3d mapping applications and image-based geo web-services. Georeferenced stereo images are ideally suited for the 3d mapping of street furniture and visible infrastructure objects, pavement inspection, asset management tasks or image based change detection. As in most mobile mapping systems, the georeferencing of the mapping sensors and observations – in our case of the imaging sensors – normally relies on direct georeferencing based on INS/GNSS navigation sensors. However, in urban canyons the achievable direct georeferencing accuracy of the dynamically captured stereo image sequences is often insufficient or at least degraded. Furthermore, many of the mentioned application scenarios require homogeneous georeferencing accuracy within a local reference frame over the entire mapping perimeter. To achieve these demands georeferencing approaches are presented and cost efficient workflows are discussed which allows validating and updating the INS/GNSS based trajectory with independently estimated positions in cases of prolonged GNSS signal outages in order to increase the georeferencing accuracy up to the project requirements.

  12. In vitro and in vivo comparison of wrist MR imaging at 3.0 and 7.0 tesla using a gradient echo sequence and identical eight-channel coil array designs.

    Science.gov (United States)

    Nordmeyer-Massner, Jurek A; Wyss, Michael; Andreisek, Gustav; Pruessmann, Klaas P; Hodler, Juerg

    2011-03-01

    To evaluate in vivo MR imaging of the wrist at 3.0 Tesla (T) and 7.0T quantitatively and qualitatively. To enable unbiased signal-to-noise ratio (SNR) comparisons, geometrically identical eight-channel receiver arrays were used at both field strengths. First, in vitro images of a phantom bottle were acquired at 3.0T and 7.0T to obtain an estimate of the maximum SNR gain that can be expected. MR images of the dominant wrist of 10 healthy volunteers were acquired at both field strengths. All measurements were done using the same sequence parameters. Quantitative SNR maps were calculated on a pixel-by-pixel basis and analyzed in several regions-of-interest. Furthermore, the images were qualitatively evaluated by two independent radiologists. The quantitative analysis showed SNR increases of up to 100% at 7.0T compared with 3.0T, with considerable variation between different anatomical structures. The qualitative analysis revealed no significant difference in the visualization of anatomical structures comparing 3.0T and 7.0T MR images (P>0.05). The presented results establish the SNR benefits of the transition from 3.0T to 7.0T for wrist imaging without bias by different array designs and based on exact, algebraic SNR quantification. The observed SNR increase nearly reaches expected values but varies greatly between different tissues. It does not necessarily improve the visibility of anatomic structures but adds valuable latitude for sequence optimization. Copyright © 2011 Wiley-Liss, Inc.

  13. Database for radiation therapy images

    International Nuclear Information System (INIS)

    Shalev, S.; Cosby, S.; Leszczynski, K.; Chu, T.

    1989-01-01

    The authors have developed a database for images acquired during simulation and verification of radiation treatments. Simulation images originate as planning films that are digitized with a video camera, or through direct digitization of fluoroscopic images. Verification images may also be digitized from portal films or acquired with an on-line portal imaging system. Images are classified by the patient, the fraction, the field direction, static or dynamic (movie) sequences, and the type of processing applied. Additional parameters indicate whether the source is a simulation or treatment, whether images are digitized film or real-time acquisitions, and whether treatment is portal or double exposure for beam localization. Examples are presented for images acquired, processed, stored, and displayed with on-line portal imaging system (OPIUM) and digital simulation system (FLIP)

  14. Study of the voxel-based specific regional analysis system for Alzheimer's disease imaging sequence after magnetic resonance apparatus replacement

    International Nuclear Information System (INIS)

    Tsukagoshi, Yuki; Kanai, Yoshihiro; Yasui, Gou; Abe, Yuuji; Maemura, Keisuke; Nakazawa, Masaki; Yamaji, Yuugo; Mihara, Ban

    2012-01-01

    In our institute, an MR apparatus, MAGNETOM VISION (Siemens) was replaced by ECHELON Vega (HITACHI). Z-score data acquired by MPRAGE (VISION) was compared with those by radio frequency-spoiled steady-state acquisition with rewinded gradient echo (RSSG) and gradient echo inversion recovery (GEIR) (ECHELON). For this study, ten normal volunteers were recruited and their data ware obtained within two months using both apparatuses. In addition, the difference of the contrasts of the images of these apparatuses was compared. There was a significant difference between Z-scores of MPRAGE and RSSG while there was no difference between MPRAGE and GEIR. As for the contrast, data of MPRAGE were similar to those of GEIR. To compare Z-scores acquired with MAGNTOM VISION (Siemens), it seems appropriate to use GEIR in ECHELON Vega. (author)

  15. Borehole-explosion and air-gun data acquired in the 2011 Salton Seismic Imaging Project (SSIP), southern California: description of the survey

    Science.gov (United States)

    Rose, Elizabeth J.; Fuis, Gary S.; Stock, Joann M.; Hole, John A.; Kell, Annie M.; Kent, Graham; Driscoll, Neal W.; Goldman, Mark; Reusch, Angela M.; Han, Liang; Sickler, Robert R.; Catchings, Rufus D.; Rymer, Michael J.; Criley, Coyn J.; Scheirer, Daniel S.; Skinner, Steven M.; Slayday-Criley, Coye J.; Murphy, Janice M.; Jensen, Edward G.; McClearn, Robert; Ferguson, Alex J.; Butcher, Lesley A.; Gardner, Max A.; Emmons, Iain; Loughran, Caleb L.; Svitek, Joseph R.; Bastien, Patrick C.; Cotton, Joseph A.; Croker, David S.; Harding, Alistair J.; Babcock, Jeffrey M.; Harder, Steven H.; Rosa, Carla M.

    2013-01-01

    earthquake energy can travel through the sediments. All of these factors determine how hard the earth will shake during a major earthquake. If we can improve on our understanding of how and where earthquakes will occur, and how strong their resultant shaking will be, then buildings can be designed or retrofitted accordingly in order to resist damage and collapse, and emergency plans can be adequately prepared. In addition, SSIP will investigate the processes of rifting and magmatism in the Salton Trough in order to better understand this important plate-boundary region. The Salton Trough is a unique rift in that subsidence is accompanied by huge influxes of infilling sediment from the Colorado River. Volcanism that accompanies the subsidence here is muted by these influxes of sediment. The Salton Trough, in the central part of the Imperial Valley, is apparently made up of entirely new crust: young sediment in the upper crust and basaltic intrusive rocks in the mid-to-lower crust (Fuis and others, 1984). Similar to the ultrasound and computed tomography (CT) scans performed by the medical industry, seismic imaging is a collection of techniques that enable scientists to obtain a picture of what is underground. The petroleum industry routinely uses these techniques to search for oil and gas at relatively shallow depths; however, the scope of this project demanded that we image as much as 30 km into the Earth’s crust. This project generated and recorded seismic waves, similar to sound waves, which move downward into the Earth and are bent (refracted) or echoed (reflected) back to the surface. SSIP acquired data in a series of intersecting lines that cover key areas of the Salton Trough. The sources of sound waves were detonations (shots) in deep boreholes, designed to create energy equivalent to magnitude 1–2 earthquakes. The study region routinely experiences earthquakes of these magnitudes, but earthquakes are not located in such a way as to permit us to create the

  16. Comparison of modern 3D and 2D MR imaging sequences of the wrist at 3 Tesla

    International Nuclear Information System (INIS)

    Rehnitz, C.; Klaan, B.; Amarteifio, E.; Kauczor, H.U.; Weber, M.A.; Stillfried, F. von; Burkholder, I.

    2016-01-01

    To compare the image quality of modern 3 D and 2 D sequences for dedicated wrist imaging at 3 Tesla (T) MRI. At 3 T MRI, 18 patients (mean age: 36.2 years) with wrist pain and 16 healthy volunteers (mean age: 26.4 years) were examined using 2 D proton density-weighted fat-saturated (PDfs), isotropic 3 D TrueFISP, 3 D MEDIC, and 3 D PDfs SPACE sequences. Image quality was rated on a five-point scale (0 - 4) including overall image quality (OIQ), visibility of important structures (cartilage, ligaments, TFCC) and degree of artifacts. Signal-to-noise ratios (SNR) and contrast-to-noise ratios (CNR) of cartilage/bone/muscle/fluid as well as the mean overall SNR/CNR were calculated using region-of-interest analysis. ANOVA, paired t-, and Wilcoxon-signed-rank tests were applied. The image quality of all tested sequences was superior to 3 D PDfs SPACE (p < 0.01). 3 D TrueFISP had the highest combined cartilage score (mean: 3.4) and performed better in cartilage comparisons against 3 D PDfs SPACE in both groups and 2 D PDfs in volunteers (p < 0.05). 3 D MEDIC performed better in 7 of 8 comparisons (p < 0.05) regarding ligaments and TFCC. 2 D PDfs provided constantly high scores. The mean overall SNR/CNR for 2 D PDfs, 3 D PDfs SPACE, 3 D TrueFISP, and 3 D MEDIC were 68/65, 32/27, 45/47, and 57/45, respectively. 2 D PDfs performed best in most SNR/CNR comparisons (p < 0.05) and 3 D MEDIC performed best within the 3 D sequences (p < 0.05). Except 3 D PDfs SPACE, all tested 3 D and 2 D sequences provided high image quality. 3 D TrueFISP was best for cartilage imaging, 3 D MEDIC for ligaments and TFCC and 2 D PDfs for general wrist imaging.

  17. Basic evaluation of the new pulse sequence for simultaneous acquisition of T1- and T2-weighted images

    International Nuclear Information System (INIS)

    Kurose, Atsunari; Takahashi, Tohru; Ohishi, Tae; Ishikawa, Akihiro

    2006-01-01

    A novel pulse sequence that enables simultaneous acquisition of T1-weighted (T1W) and T2-weighted (T2W) images is presented. In this new technique, the inversion recovery (IR) pulse of conventional fast inversion recovery (Fast IR) is replaced with a pulse train that consists of a fast spin echo (FSE) and 180(y)+90(x) for driven inversion (DI). By using a shorter T1 and independent k-space ordering, the first part of the sequence provides T2W images and the second part provides T1W images, thereby enabling simultaneous acquisition in a single scan time comparable to that of Fast IR. Signal simulation also was conducted, and this was compared with conventional scanning techniques using normal volunteers. In the human studies, both T1W and T2W images showed the same image quality as conventional images, suggesting the potential for this technique to replace the combination of Fast IR and T2W FSE for scan-time reduction. (author)

  18. Method for automatic localization of MR-visible markers using morphological image processing and conventional pulse sequences: feasibility for image-guided procedures.

    Science.gov (United States)

    Busse, Harald; Trampel, Robert; Gründer, Wilfried; Moche, Michael; Kahn, Thomas

    2007-10-01

    To evaluate the feasibility and accuracy of an automated method to determine the 3D position of MR-visible markers. Inductively coupled RF coils were imaged in a whole-body 1.5T scanner using the body coil and two conventional gradient echo sequences (FLASH and TrueFISP) and large imaging volumes up to (300 mm(3)). To minimize background signals, a flip angle of approximately 1 degrees was used. Morphological 2D image processing in orthogonal scan planes was used to determine the 3D positions of a configuration of three fiducial markers (FMC). The accuracies of the marker positions and of the orientation of the plane defined by the FMC were evaluated at various distances r(M) from the isocenter. Fiducial marker detection with conventional equipment (pulse sequences, imaging coils) was very reliable and highly reproducible over a wide range of experimental conditions. For r(M) image processing is feasible, simple, and very accurate. In combination with safe wireless markers, the method is found to be useful for image-guided procedures. (c) 2007 Wiley-Liss, Inc.

  19. Differentiation of thrombus from pannus as the cause of acquired mechanical prosthetic heart valve obstruction by non-invasive imaging: a review of the literature

    NARCIS (Netherlands)

    Tanis, Wilco; Habets, Jesse; van den Brink, Renee B. A.; Symersky, Petr; Budde, Ricardo P. J.; Chamuleau, Steven A. J.

    2014-01-01

    For acquired mechanical prosthetic heart valve (PHV) obstruction and suspicion on thrombosis, recently updated European Society of Cardiology guidelines advocate the confirmation of thrombus by transthoracic echocardiography, transesophageal echocardiography (TEE), and fluoroscopy. However, no

  20. Evaluation of pneumonia in children: comparison of MRI with fast imaging sequences at 1.5T with chest radiographs

    Energy Technology Data Exchange (ETDEWEB)

    Yikilmaz, Ali; Koc, Ali; Coskun, Abdulhakim (Dept. of Radiology, Erciyes Medical School, Kayseri (Turkey)); Ozturk, Mustafa K (Dept. of Pediatric Infectious Diseases, Erciyes Medical School, Kayseri (Turkey)); Mulkern, Robert V; Lee, Edward Y (Dept. of Radiology and Dept. of Medicine, Pulmonary Div., Children' s Hospital Boston and Harvard Medical School, Boston (United States)), email: Edward.lee@childrens.harvard.edu

    2011-10-15

    Background Although there has been a study aimed at magnetic resonance imaging (MRI) evaluation of pneumonia in children at a low magnetic field (0.2T), there is no study which assessed the efficacy of MRI, particularly with fast imaging sequences at 1.5T, for evaluating pneumonia in children. Purpose To investigate the efficacy of chest MRI with fast imaging sequences at 1.5T for evaluating pneumonia in children by comparing MRI findings with those of chest radiographs. Material and Methods This was an Institutional Review Board-approved, HIPPA-compliant prospective study of 40 consecutive pediatric patients (24 boys, 16 girls; mean age 7.3 years +- 6.6 years) with pneumonia, who underwent PA and lateral chest radiographs followed by MRI within 24 h. All MRI studies were obtained in axial and coronal planes with two different fast imaging sequences: T1-weighted FFE (Fast Field Echo) (TR/TE: 83/4.6) and T2-weighted B-FFE M2D (Balanced Fast Field Echo Multiple 2D Dimensional) (TR/TE: 3.2/1.6). Two experienced pediatric radiologists reviewed each chest radiograph and MRI for the presence of consolidation, necrosis/abscess, bronchiectasis, and pleural effusion. Chest radiograph and MRI findings were compared with Kappa statistics. Results All consolidation, lung necrosis/abscess, bronchiectasis, and pleural effusion detected with chest radiographs were also detected with MRI. There was statistically substantial agreement between chest radiographs and MRI in detecting consolidation (k = 0.78) and bronchiectasis (k = 0.72) in children with pneumonia. The agreement between chest radiographs and MRI was moderate for detecting necrosis/abscess (k = 0.49) and fair for detecting pleural effusion (k = 0.30). Conclusion MRI with fast imaging sequences is comparable to chest radiographs for evaluating underlying pulmonary consolidation, bronchiectasis, necrosis/abscess, and pleural effusion often associated with pneumonia in children

  1. Variability in prostate and seminal vesicle delineations defined on magnetic resonance images, a multi-observer, -center and -sequence study

    DEFF Research Database (Denmark)

    Nyholm, Tufve; Jonsson, Joakim; Söderström, Karin

    2013-01-01

    and approximately equal for the prostate and seminal vesicles. Large differences in variability were observed for individual patients, and also for individual imaging sequences used at the different centers. There was however no indication of decreased variability with higher field strength. CONCLUSION: The overall......BACKGROUND: The use of magnetic resonance (MR) imaging as a part of preparation for radiotherapy is increasing. For delineation of the prostate several publications have shown decreased delineation variability using MR compared to computed tomography (CT). The purpose of the present work....... Two physicians from each center delineated the prostate and the seminal vesicles on each of the 25 image sets. The variability between the delineations was analyzed with respect to overall, intra- and inter-physician variability, and dependence between variability and origin of the MR images, i...

  2. Whole body sodium MRI at 3T using an asymmetric birdcage resonator and short echo time sequence: first images of a male volunteer

    Science.gov (United States)

    Wetterling, Friedrich; Corteville, Dominique M.; Kalayciyan, Raffi; Rennings, Andreas; Konstandin, Simon; Nagel, Armin M.; Stark, Helmut; Schad, Lothar R.

    2012-07-01

    Sodium magnetic resonance imaging (23Na MRI) is a non-invasive technique which allows spatial resolution of the tissue sodium concentration (TSC) in the human body. TSC measurements could potentially serve to monitor early treatment success of chemotherapy on patients who suffer from whole body metastases. Yet, the acquisition of whole body sodium (23Na) images has been hampered so far by the lack of large resonators and the extremely low signal-to-noise ratio (SNR) achieved with existing resonator systems. In this study, a 23Na resonator was constructed for whole body 23Na MRI at 3T comprising of a 16-leg, asymmetrical birdcage structure with 34 cm height, 47.5 cm width and 50 cm length. The resonator was driven in quadrature mode and could be used either as a transceiver resonator or, since active decoupling was included, as a transmit-only resonator in conjunction with a receive-only (RO) surface resonator. The relative B1-field profile was simulated and measured on phantoms, and 3D whole body 23Na MRI data of a healthy male volunteer were acquired in five segments with a nominal isotropic resolution of (6 × 6 × 6) mm3 and a 10 min acquisition time per scan. The measured SNR values in the 23Na-MR images varied from 9 ± 2 in calf muscle, 15 ± 2 in brain tissue, 23 ± 2 in the prostate and up to 42 ± 5 in the vertebral discs. Arms, legs, knees and hands could also be resolved with applied resonator and short time-to-echo (TE) (0.5 ms) radial sequence. Up to fivefold SNR improvement was achieved through combining the birdcage with local RO surface coil. In conclusion, 23Na MRI of the entire human body provides sub-cm spatial resolution, which allows resolution of all major human body parts with a scan time of less than 60 min.

  3. Pulseq-Graphical Programming Interface: Open source visual environment for prototyping pulse sequences and integrated magnetic resonance imaging algorithm development.

    Science.gov (United States)

    Ravi, Keerthi Sravan; Potdar, Sneha; Poojar, Pavan; Reddy, Ashok Kumar; Kroboth, Stefan; Nielsen, Jon-Fredrik; Zaitsev, Maxim; Venkatesan, Ramesh; Geethanath, Sairam

    2018-03-11

    To provide a single open-source platform for comprehensive MR algorithm development inclusive of simulations, pulse sequence design and deployment, reconstruction, and image analysis. We integrated the "Pulseq" platform for vendor-independent pulse programming with Graphical Programming Interface (GPI), a scientific development environment based on Python. Our integrated platform, Pulseq-GPI, permits sequences to be defined visually and exported to the Pulseq file format for execution on an MR scanner. For comparison, Pulseq files using either MATLAB only ("MATLAB-Pulseq") or Python only ("Python-Pulseq") were generated. We demonstrated three fundamental sequences on a 1.5 T scanner. Execution times of the three variants of implementation were compared on two operating systems. In vitro phantom images indicate equivalence with the vendor supplied implementations and MATLAB-Pulseq. The examples demonstrated in this work illustrate the unifying capability of Pulseq-GPI. The execution times of all the three implementations were fast (a few seconds). The software is capable of user-interface based development and/or command line programming. The tool demonstrated here, Pulseq-GPI, integrates the open-source simulation, reconstruction and analysis capabilities of GPI Lab with the pulse sequence design and deployment features of Pulseq. Current and future work includes providing an ISMRMRD interface and incorporating Specific Absorption Ratio and Peripheral Nerve Stimulation computations. Copyright © 2018 Elsevier Inc. All rights reserved.

  4. Thickness of patellofemoral articular cartilage as measured on MR imaging: sequence comparison of accuracy, reproducibility, and interobserver variation

    Energy Technology Data Exchange (ETDEWEB)

    Van Leersum, M.D. [Dept. of Radiology, Thomas Jefferson Univ. Hospital, Philadelphia, PA (United States); Schweitzer, M.E. [Dept. of Radiology, Thomas Jefferson Univ. Hospital, Philadelphia, PA (United States); Gannon, F. [Dept. of Pathology, Thomas Jefferson Univ. Hospital, Philadelphia, PA (United States); Vinitski, S. [Dept. of Radiology, Thomas Jefferson Univ. Hospital, Philadelphia, PA (United States); Finkel, G. [Dept. of Pathology, Thomas Jefferson Univ. Hospital, Philadelphia, PA (United States); Mitchell, D.G. [Dept. of Radiology, Thomas Jefferson Univ. Hospital, Philadelphia, PA (United States)

    1995-08-01

    This study was undertaken to assess the accuracy, precision, and reliability of magnetic resonance (MR) measurements of articular cartilage. Fifteen cadaveric patellas were imaged in the axial plane at 1.5 T. Gradient echo and fat-suppressed FSE, T2-weighted, proton density, and T1-weighted sequences were performed. We measured each 5-mm section separately at three standardized positions, giving a total of 900 measurements. These findings were correlated with independently performed measurements of the corresponding anatomic sections. A hundred random measurements were also evaluated for reproducibility and interobserver variation. Although all sequences were highly accurate, the T1-weighted images were the most accurate, with a mean difference of 0.25 mm and a correlation coefficient of 0.85. All sequences were also highly reproducible with little inter-observer variation. In an attempt to improve the accuracy of the MR measurements further, we retrospectively evaluated all measurements with discrepancies greater than 1 mm from the specimen. All these differences were attributable to focal defects causing exaggeration of the thickness on MR imaging. (orig.)

  5. Thickness of patellofemoral articular cartilage as measured on MR imaging: sequence comparison of accuracy, reproducibility, and interobserver variation

    International Nuclear Information System (INIS)

    Van Leersum, M.D.; Schweitzer, M.E.; Gannon, F.; Vinitski, S.; Finkel, G.; Mitchell, D.G.

    1995-01-01

    This study was undertaken to assess the accuracy, precision, and reliability of magnetic resonance (MR) measurements of articular cartilage. Fifteen cadaveric patellas were imaged in the axial plane at 1.5 T. Gradient echo and fat-suppressed FSE, T2-weighted, proton density, and T1-weighted sequences were performed. We measured each 5-mm section separately at three standardized positions, giving a total of 900 measurements. These findings were correlated with independently performed measurements of the corresponding anatomic sections. A hundred random measurements were also evaluated for reproducibility and interobserver variation. Although all sequences were highly accurate, the T1-weighted images were the most accurate, with a mean difference of 0.25 mm and a correlation coefficient of 0.85. All sequences were also highly reproducible with little inter-observer variation. In an attempt to improve the accuracy of the MR measurements further, we retrospectively evaluated all measurements with discrepancies greater than 1 mm from the specimen. All these differences were attributable to focal defects causing exaggeration of the thickness on MR imaging. (orig.)

  6. Automated Leaf Tracking using Multi-view Image Sequences of Maize Plants for Leaf-growth Monitoring

    Science.gov (United States)

    Das Choudhury, S.; Awada, T.; Samal, A.; Stoerger, V.; Bashyam, S.

    2017-12-01

    Extraction of phenotypes with botanical importance by analyzing plant image sequences has the desirable advantages of non-destructive temporal phenotypic measurements of a large number of plants with little or no manual intervention in a relatively short period of time. The health of a plant is best interpreted by the emergence timing and temporal growth of individual leaves. For automated leaf growth monitoring, it is essential to track each leaf throughout the life cycle of the plant. Plants are constantly changing organisms with increasing complexity in architecture due to variations in self-occlusions and phyllotaxy, i.e., arrangements of leaves around the stem. The leaf cross-overs pose challenges to accurately track each leaf using single view image sequence. Thus, we introduce a novel automated leaf tracking algorithm using a graph theoretic approach by multi-view image sequence analysis based on the determination of leaf-tips and leaf-junctions in the 3D space. The basis of the leaf tracking algorithm is: the leaves emerge using bottom-up approach in the case of a maize plant, and the direction of leaf emergence strictly alternates in terms of direction. The algorithm involves labeling of the individual parts of a plant, i.e., leaves and stem, following graphical representation of the plant skeleton, i.e., one-pixel wide connected line obtained from the binary image. The length of the leaf is measured by the number of pixels in the leaf skeleton. To evaluate the performance of the algorithm, a benchmark dataset is indispensable. Thus, we publicly release University of Nebraska-Lincoln Component Plant Phenotyping dataset-2 (UNL-CPPD-2) consisting of images of the 20 maize plants captured by visible light camera of the Lemnatec Scanalyzer 3D high throughout plant phenotyping facility once daily for 60 days from 10 different views. The dataset is aimed to facilitate the development and evaluation of leaf tracking algorithms and their uniform comparisons.

  7. MR venography using the 3D-MEDIC (multi echo data imaging combination) sequence for lower extremities

    International Nuclear Information System (INIS)

    Kitagawa, Hisashi; Kishi, Takayuki; Saito, Ryo; Shohji, Tomokazu; Noguchi, Keiji; Sunohara, Nobuo

    2008-01-01

    It is possible to diagnose varicose vein from medical history and physical examinations including inspection and palpation. Non-contrast enhanced MRV (magnetic resonance venography) is becoming popular because it can be easily performed without being affected by the radiographer's skill. We thought that the use of MEDIC (multi echo data imaging combination) would enable us to delineate varicose veins within a short acquisition time and without need for synchronization or contrast enhancement. We used the SIEMENS MAGNETOM Avanto 1.5-Tesla unit to acquire images. Our subjects were five healthy volunteers and five patients with varicose vein. The signal strength of deep veins and muscles were measured. The SNR (signal-to-nose ratio) of deep veins and the CNR (contrast-to-noise ratio) between deep veins and muscles were also measured. Flip angle, fat suppression methods, MTC (magnetic transfer contrast) pulse, and combined echo. Using the optimum image acquisition protocol following our preliminary study with varicose vein patients, the ability of the 3D-MEDIC method to delineate varicose veins was compared with that of the electrocardiogram (ECG)-synchronized two-dimensional time of flight (2D-TOF) method. We found that the following settings would enable us to acquire images from a wide range=coronal, within short acquisition time and needless ECG-triggering. Flip angle=20 degrees, fat suppression method=water excitation, MTC pulse=ON, combined echo=2. 3D-MEDIC was better than the 2D-TOF method in delineating the varicose vein itself and the connection between the varicose vein and deep veins. It is expected that 3D-MEDIC may be useful in the clinical diagnosis of varicose veins. (author)

  8. Generation of synthetic image sequences for the verification of matching and tracking algorithms for deformation analysis

    Science.gov (United States)

    Bethmann, F.; Jepping, C.; Luhmann, T.

    2013-04-01

    This paper reports on a method for the generation of synthetic image data for almost arbitrary static or dynamic 3D scenarios. Image data generation is based on pre-defined 3D objects, object textures, camera orientation data and their imaging properties. The procedure does not focus on the creation of photo-realistic images under consideration of complex imaging and reflection models as they are used by common computer graphics programs. In contrast, the method is designed with main emphasis on geometrically correct synthetic images without radiometric impact. The calculation process includes photogrammetric distortion models, hence cameras with arbitrary geometric imaging characteristics can be applied. Consequently, image sets can be created that are consistent to mathematical photogrammetric models to be used as sup-pixel accurate data for the assessment of high-precision photogrammetric processing methods. In the first instance the paper describes the process of image simulation under consideration of colour value interpolation, MTF/PSF and so on. Subsequently the geometric quality of the synthetic images is evaluated with ellipse operators. Finally, simulated image sets are used to investigate matching and tracking algorithms as they have been developed at IAPG for deformation measurement in car safety testing.

  9. Infrared upconversion hyperspectral imaging

    DEFF Research Database (Denmark)

    Kehlet, Louis Martinus; Tidemand-Lichtenberg, Peter; Dam, Jeppe Seidelin

    2015-01-01

    In this Letter, hyperspectral imaging in the mid-IR spectral region is demonstrated based on nonlinear frequency upconversion and subsequent imaging using a standard Si-based CCD camera. A series of upconverted images are acquired with different phase match conditions for the nonlinear frequency...... conversion process. From this, a sequence of monochromatic images in the 3.2-3.4 mu m range is generated. The imaged object consists of a standard United States Air Force resolution target combined with a polystyrene film, resulting in the presence of both spatial and spectral information in the infrared...... image. (C) 2015 Optical Society of America...

  10. Efficient optical Kerr gate of Bi2O3–B2O3–SiO2 glass for acquiring high contrast ballistic imaging in turbid medium

    International Nuclear Information System (INIS)

    Zhan, Pingping; Tan, Wenjiang; Wu, Bin; Si, Jinhai; Chen, Feng; Hou, Xun; Liu, Xin

    2013-01-01

    We investigated the ballistic imaging of a 1.41 line pair mm −1 section of a resolution test chart hidden behind a solution of polystyrene spheres with a femtosecond optical Kerr gate (OKG). A better transillumination image contrast could be acquired with an OKG of Bi 2 O 3 –B 2 O 3 –SiO 2 (BI) glass than that with an OKG of fused silica in a highly scattering media, which indicated that the BI glass was a better OKG medium due to its large nonlinear refractive index. (paper)

  11. Fat suppression at 2D MR imaging of the hands: Dixon method versus CHESS technique and STIR sequence.

    Science.gov (United States)

    Kirchgesner, Thomas; Perlepe, Vasiliki; Michoux, Nicolas; Larbi, Ahmed; Vande Berg, Bruno

    2017-04-01

    To compare the effectiveness of fat suppression and the signal-to-noise ratio (SNR) of the Dixon method with those of the CHESS (Chemical Shift-Selective) technique and STIR (Short Tau Inversion Recovery) sequence in hands of normal subjects at 2D MR imaging. 14 healthy volunteers (mean age of 29.4 years) consented to have both hands prospectively imaged with SE T1 Dixon, T1 CHESS, T2 Dixon, T2 CHESS and STIR sequences in a 1.5T MR scanner. Three radiologists scored the effectiveness of fat suppression in bone marrow (EFS BM ) and soft tissues (EFS ST ) in 20 joints per subject. One radiologist measured the SNR in 10 bones per subject. Statistical analysis used two-way ANOVA with random effects, paired t-test and observed agreement to assess differences in effectiveness of fat suppression, differences in SNR and inter-observer agreement. EFS BM was statistically significantly higher for T1 Dixon than for T1 CHESS and for T2 Dixon than for T2 CHESS (pCHESS and for T2 Dixon than for STIR (pCHESS (pCHESS technique at 2D T1-weighted MR imaging of the hands. At T2-weighted MR imaging, fat suppression is more effective with the Dixon method while SNR is higher with the CHESS technique. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Differentiation of thrombus from pannus as the cause of acquired mechanical prosthetic heart valve obstruction by non-invasive imaging: a review of the literature.

    Science.gov (United States)

    Tanis, Wilco; Habets, Jesse; van den Brink, Renee B A; Symersky, Petr; Budde, Ricardo P J; Chamuleau, Steven A J

    2014-02-01

    For acquired mechanical prosthetic heart valve (PHV) obstruction and suspicion on thrombosis, recently updated European Society of Cardiology guidelines advocate the confirmation of thrombus by transthoracic echocardiography, transesophageal echocardiography (TEE), and fluoroscopy. However, no evidence-based diagnostic algorithm is available for correct thrombus detection, although this is clinically important as fibrinolysis is contraindicated in non-thrombotic obstruction (isolated pannus). Here, we performed a review of the literature in order to propose a diagnostic algorithm. We performed a systematic search in Pubmed and Embase. Included publications were assessed on methodological quality based on the validated Quality Assessment of Diagnostic Accuracy Studies (QUADAS) II checklist. Studies were scarce (n = 15) and the majority were of moderate methodological quality. In total, 238 mechanical PHV's with acquired obstruction and a reliable reference standard were included for the evaluation of the role of fluoroscopy, echocardiography, or multidetector-row computed tomography (MDCT). In acquired PHV obstruction caused by thrombosis, mass detection by TEE and leaflet restriction detected by fluoroscopy were observed in the majority of cases (96 and 100%, respectively). In contrast, in acquired PHV obstruction free of thrombosis (pannus), leaflet restriction detected by fluoroscopy was absent in some cases (17%) and mass detection by TEE was absent in the majority of cases (66%). In case of mass detection by TEE, predictors for obstructive thrombus masses (compared with pannus masses) were leaflet restriction, soft echo density, and increased mass length. In situations of inconclusive echocardiography, MDCT may correctly detect pannus/thrombus based on the morphological aspects and localization. In acquired mechanical PHV obstruction without leaflet restriction and absent mass on TEE, obstructive PHV thrombosis cannot be confirmed and consequently, fibrinolysis

  13. Automatic Substitute Computed Tomography Generation and Contouring for Magnetic Resonance Imaging (MRI)-Alone External Beam Radiation Therapy From Standard MRI Sequences

    Energy Technology Data Exchange (ETDEWEB)

    Dowling, Jason A., E-mail: jason.dowling@csiro.au [CSIRO Australian e-Health Research Centre, Herston, Queensland (Australia); University of Newcastle, Callaghan, New South Wales (Australia); Sun, Jidi [University of Newcastle, Callaghan, New South Wales (Australia); Pichler, Peter [Calvary Mater Newcastle Hospital, Waratah, New South Wales (Australia); Rivest-Hénault, David; Ghose, Soumya [CSIRO Australian e-Health Research Centre, Herston, Queensland (Australia); Richardson, Haylea [Calvary Mater Newcastle Hospital, Waratah, New South Wales (Australia); Wratten, Chris; Martin, Jarad [University of Newcastle, Callaghan, New South Wales (Australia); Calvary Mater Newcastle Hospital, Waratah, New South Wales (Australia); Arm, Jameen [Calvary Mater Newcastle Hospital, Waratah, New South Wales (Australia); Best, Leah [Department of Radiology, Hunter New England Health, New Lambton, New South Wales (Australia); Chandra, Shekhar S. [School of Information Technology and Electrical Engineering, University of Queensland, Brisbane, Queensland (Australia); Fripp, Jurgen [CSIRO Australian e-Health Research Centre, Herston, Queensland (Australia); Menk, Frederick W. [University of Newcastle, Callaghan, New South Wales (Australia); Greer, Peter B. [University of Newcastle, Callaghan, New South Wales (Australia); Calvary Mater Newcastle Hospital, Waratah, New South Wales (Australia)

    2015-12-01

    Purpose: To validate automatic substitute computed tomography CT (sCT) scans generated from standard T2-weighted (T2w) magnetic resonance (MR) pelvic scans for MR-Sim prostate treatment planning. Patients and Methods: A Siemens Skyra 3T MR imaging (MRI) scanner with laser bridge, flat couch, and pelvic coil mounts was used to scan 39 patients scheduled for external beam radiation therapy for localized prostate cancer. For sCT generation a whole-pelvis MRI scan (1.6 mm 3-dimensional isotropic T2w SPACE [Sampling Perfection with Application optimized Contrasts using different flip angle Evolution] sequence) was acquired. Three additional small field of view scans were acquired: T2w, T2*w, and T1w flip angle 80° for gold fiducials. Patients received a routine planning CT scan. Manual contouring of the prostate, rectum, bladder, and bones was performed independently on the CT and MR scans. Three experienced observers contoured each organ on MRI, allowing interobserver quantification. To generate a training database, each patient CT scan was coregistered to their whole-pelvis T2w using symmetric rigid registration and structure-guided deformable registration. A new multi-atlas local weighted voting method was used to generate automatic contours and sCT results. Results: The mean error in Hounsfield units between the sCT and corresponding patient CT (within the body contour) was 0.6 ± 14.7 (mean ± 1 SD), with a mean absolute error of 40.5 ± 8.2 Hounsfield units. Automatic contouring results were very close to the expert interobserver level (Dice similarity coefficient): prostate 0.80 ± 0.08, bladder 0.86 ± 0.12, rectum 0.84 ± 0.06, bones 0.91 ± 0.03, and body 1.00 ± 0.003. The change in monitor units between the sCT-based plans relative to the gold standard CT plan for the same dose prescription was found to be 0.3% ± 0.8%. The 3-dimensional γ pass rate was 1.00 ± 0.00 (2 mm/2%). Conclusions: The MR-Sim setup and automatic s

  14. Automatic Substitute Computed Tomography Generation and Contouring for Magnetic Resonance Imaging (MRI)-Alone External Beam Radiation Therapy From Standard MRI Sequences

    International Nuclear Information System (INIS)

    Dowling, Jason A.; Sun, Jidi; Pichler, Peter; Rivest-Hénault, David; Ghose, Soumya; Richardson, Haylea; Wratten, Chris; Martin, Jarad; Arm, Jameen; Best, Leah; Chandra, Shekhar S.; Fripp, Jurgen; Menk, Frederick W.; Greer, Peter B.

    2015-01-01

    Purpose: To validate automatic substitute computed tomography CT (sCT) scans generated from standard T2-weighted (T2w) magnetic resonance (MR) pelvic scans for MR-Sim prostate treatment planning. Patients and Methods: A Siemens Skyra 3T MR imaging (MRI) scanner with laser bridge, flat couch, and pelvic coil mounts was used to scan 39 patients scheduled for external beam radiation therapy for localized prostate cancer. For sCT generation a whole-pelvis MRI scan (1.6 mm 3-dimensional isotropic T2w SPACE [Sampling Perfection with Application optimized Contrasts using different flip angle Evolution] sequence) was acquired. Three additional small field of view scans were acquired: T2w, T2*w, and T1w flip angle 80° for gold fiducials. Patients received a routine planning CT scan. Manual contouring of the prostate, rectum, bladder, and bones was performed independently on the CT and MR scans. Three experienced observers contoured each organ on MRI, allowing interobserver quantification. To generate a training database, each patient CT scan was coregistered to their whole-pelvis T2w using symmetric rigid registration and structure-guided deformable registration. A new multi-atlas local weighted voting method was used to generate automatic contours and sCT results. Results: The mean error in Hounsfield units between the sCT and corresponding patient CT (within the body contour) was 0.6 ± 14.7 (mean ± 1 SD), with a mean absolute error of 40.5 ± 8.2 Hounsfield units. Automatic contouring results were very close to the expert interobserver level (Dice similarity coefficient): prostate 0.80 ± 0.08, bladder 0.86 ± 0.12, rectum 0.84 ± 0.06, bones 0.91 ± 0.03, and body 1.00 ± 0.003. The change in monitor units between the sCT-based plans relative to the gold standard CT plan for the same dose prescription was found to be 0.3% ± 0.8%. The 3-dimensional γ pass rate was 1.00 ± 0.00 (2 mm/2%). Conclusions: The MR-Sim setup and automatic s

  15. Automatic internal crack detection from a sequence of infrared images with a triple-threshold Canny edge detector

    Science.gov (United States)

    Wang, Gaochao; Tse, Peter W.; Yuan, Maodan

    2018-02-01

    Visual inspection and assessment of the condition of metal structures are essential for safety. Pulse thermography produces visible infrared images, which have been widely applied to detect and characterize defects in structures and materials. When active thermography, a non-destructive testing tool, is applied, the necessity of considerable manual checking can be avoided. However, detecting an internal crack with active thermography remains difficult, since it is usually invisible in the collected sequence of infrared images, which makes the automatic detection of internal cracks even harder. In addition, the detection of an internal crack can be hindered by a complicated inspection environment. With the purpose of putting forward a robust and automatic visual inspection method, a computer vision-based thresholding method is proposed. In this paper, the image signals are a sequence of infrared images collected from the experimental setup with a thermal camera and two flash lamps as stimulus. The contrast of pixels in each frame is enhanced by the Canny operator and then reconstructed by a triple-threshold system. Two features, mean value in the time domain and maximal amplitude in the frequency domain, are extracted from the reconstructed signal to help distinguish the crack pixels from others. Finally, a binary image indicating the location of the internal crack is generated by a K-means clustering method. The proposed procedure has been applied to an iron pipe, which contains two internal cracks and surface abrasion. Some improvements have been made for the computer vision-based automatic crack detection methods. In the future, the proposed method can be applied to realize the automatic detection of internal cracks from many infrared images for the industry.

  16. Effectiveness of the STIR turbo spin–echo sequence MR imaging in evaluation of lymphadenopathy in esophageal cancer

    International Nuclear Information System (INIS)

    Alper, Fatih; Turkyilmaz, Atila; Kurtcan, Serpil; Aydin, Yener; Onbas, Omer; Acemoglu, Hamit; Eroglu, Atilla

    2011-01-01

    Purpose: We have investigated the utility of the STIR TSE sequence in the differentiation of benign from malignant mediastinal lymph nodes in patients with esophageal cancer. Patients and methods: This study included 35 consecutive patients who were diagnosed as esophageal cancer and were undergone surgery. STIR TSE sequences were obtained as the ECG trigger. The signal intensity of the benign and malign lymph nodes, normal esophagus, and pathologic esophagus can be calculated on STIR sequence. Results: Pathologically, the number of total lymph nodes in 35 operated cases was 482. Approximately 152 lymph nodes were detected with MR imaging. Of these, 28 were thought to be malignant, and 124 were thought to be benign, although 32 were malignant and 120 were benign according pathological results. The ratio of benign lymph node intensity value to normal esophagus intensity value was 0.73 ± 0.3. The ratio of malignant lymph node intensity value to normal esophagus intensity value ratio was 2.03 ± 0.4. According to these results, the sensitivity of MR was 81.3%, the specificity was 98.3%. Conclusion: We think that if motionless images can be obtained with MRI, we may be able to differentiate benign lymph nodes from malignant ones.

  17. An Improved Image Encryption Algorithm Based on Cyclic Rotations and Multiple Chaotic Sequences: Application to Satellite Images

    Directory of Open Access Journals (Sweden)

    MADANI Mohammed

    2017-10-01

    Full Text Available In this paper, a new satellite image encryption algorithm based on the combination of multiple chaotic systems and a random cyclic rotation technique is proposed. Our contribution consists in implementing three different chaotic maps (logistic, sine, and standard combined to improve the security of satellite images. Besides enhancing the encryption, the proposed algorithm also focuses on advanced efficiency of the ciphered images. Compared with classical encryption schemes based on multiple chaotic maps and the Rubik's cube rotation, our approach has not only the same merits of chaos systems like high sensitivity to initial values, unpredictability, and pseudo-randomness, but also other advantages like a higher number of permutations, better performances in Peak Signal to Noise Ratio (PSNR and a Maximum Deviation (MD.

  18. Effects of imaging gradients in sequences with varying longitudinal storage time-Case of diffusion exchange imaging

    DEFF Research Database (Denmark)

    Lasic, Samo; Lundell, Henrik; Topgaard, Daniel

    2017-01-01

    low-pass diffusion filtering during the LS interval, which is more pronounced at lower exchange rates. For a total exchange rate constant larger than 1 s-1, the AXR bias is expected to be negligible when slices thicker than 2.5mm are used. Conclusion: In correlation experiments like FEXI, relying...... on LS with variable duration, imaging gradients may cause disrupting effects that cannot be easily mitigated and should be carefully considered for unbiased results. In typical clinical applications of FEXI, the imaging gradients are expected to cause a negligible AXR bias. However, the AXR bias may...

  19. Community-acquired pneumonia

    International Nuclear Information System (INIS)

    Poetter-Lang, S.; Herold, C.J.

    2017-01-01

    The diagnosis of community-acquired pneumonia (CAP) is often not possible based only on the clinical symptoms and biochemical parameters. For every patient with the suspicion of CAP, a chest radiograph in two planes should be carried out. Additionally, a risk stratification for the decision between outpatient therapy or hospitalization is recommended. Based on the evaluation of the different radiological patterns as well as their extent and distribution, a rough allocation to so-called pathogen groups as well as a differentiation between viral and bacterial infections are possible; however, because different pathogens cause different patterns an accurate correlation is not feasible by relying purely on imaging. The radiological findings serve as proof or exclusion of pneumonia and can also be used to evaluate the extent of the disease (e.g. monolobular, multilobular, unilateral or bilateral). In cases of prolonged disease, suspicion of complications (e.g. pleural effusion or empyema, necrotizing pneumonia or abscess) or comorbid conditions (e.g. underlying pulmonary or mediastinal diseases) computed tomography is an important diagnostic tool in addition to chest radiography. Ultrasound is often used to diagnose pleural processes (e.g. parapneumonic effusion or pleural empyema). (orig.) [de

  20. Usefulness of low-field FlAIR sequence in MR imaging of intracranial tumors

    International Nuclear Information System (INIS)

    Sokolowska, D.; Sasiadek, M.; Zimny, A.

    2004-01-01

    Plain MR study is often insufficient for visualization of all important details of intracranial tumors, hence there are attempts to use supplementary MR techniques. One of them is FLAIR (fluid attenuated inversion recovery) sequence which previously was available only in high-field MR units, but recently has been introduced also in less expensive low-field units. FLAIR is already widely used in the diagnostics of ischemic and demyelinating lesions, while there are few papers concerning its application in intracranial tumors, none of them regarding low-field MR units.The aim of our study was detailed evaluation of low-field FLAIR in the diagnostics of intracranial tumors. The material consisted of 76 patients with intracranial tumors, who were examined with low-field open MR unit (0.23 Tesla). In all patients, standard T2-weighted and T1-weighted (before and after contrast enhancement) sequences, as well as FLAIR sequence, were performed. The following symptoms were compared in the aforementioned sequences: tumor-edema, edema-brain and tumor-brain borders, visualization of tumour structure, vessels in the tumor area and precise tumor localization. A superiority of FLAIR in assessment of all symptoms has been confirmed, at least in part of the patient group. It concerned particularly the evaluation of brain-edema and edema-brain borders which were better visible with FLAIR than with all other sequences in 29 and 30 patients, respectively. In the assessment of the remaining symptoms (tumor-brain border, tumor structure, visualization of vessels, tumor localization) FLAIR was superior to other sequences in smaller number of patients (13,11,11 and 12, respectively). Totally, in 48 out of 76 patients (63.2%) FLAIR allowed better assessment of at least one of the analyzed symptoms. Low-field MR FLAIR enriches diagnostic information in majority of patients with intracranial tumors, therefore it should be included routinely in the diagnostic algorithm in this group of

  1. Performance of Correspondence Algorithms in Vision-Based Driver Assistance Using an Online Image Sequence Database

    DEFF Research Database (Denmark)

    Klette, Reinhard; Krüger, Norbert; Vaudrey, Tobi

    2011-01-01

    the classification of recorded video data into situations defined by a cooccurrence of some events in recorded traffic scenes. About 100-400 stereo frames (or 4-16 s of recording) are considered a basic sequence, which will be identified with one particular situation. Future testing is expected to be on data...

  2. Hepatic adenomatosis: rapid sequence MR imaging following gadolinium enhancement: a case report

    International Nuclear Information System (INIS)

    Brummett, D.; Burton, E.M.; Sabio, H.

    1999-01-01

    Hepatic adenomas are primary liver tumors usually associated with underlying metabolic disease or with anabolic steroid or oral contraceptive use. Hepatic adenomatosis (HA) is defined as the presence of more than four adenomas. Only 13 cases of HA have been reported in patients without glycogen storage disease or steroid use. We report a case of HA imaged by postcontrast T1-weighted images obtained during a breath-holding series. The lesions were most conspicuous 3-4 min after contrast administration; 4 of the 5 tumors were not identified on T2-weighted images. Unlike previous reports of HA in which the lesions remained hyperintense during sequential postcontrast imaging, the smaller lesions in this case demonstrated contrast washout, thereby distinguishing them from hemangiomata. (orig.)

  3. Pulse sequence optimization for superparamagnetic iron oxide-enhaced MR imaging in the detection of hepatic VX2 tumors in rabbits

    International Nuclear Information System (INIS)

    Jang, Hyun Jung; Han, Joon Koo; Lee, Kyoung Ho; Kim, Se Hyung; Choi, Byung Ihn; Kim, Tae Kyoung

    2003-01-01

    The purpose of this experimental study was to determine the optimal pulse sequences for SPIO-enhanced MR imaging in the evaluation of multiple hepatic tumors. Twelve rabbits with multiple VX2 liver tumors underwent SPOI-enhanced MRI using the following nine pulse sequences: TSE T2-weighted imaging (T2W1), TSE proton density-weighted imaging(PDWI), and GRE T2*-weighted imaging (T2*W1) with seven different echo times (TE). Liver-lesion contrast-to-noise ratios (CNRs) were calculated, and images were also assessed qualitatively by two radiologists, who reached a consensus as to lesion conspicuity and imaging artifacts using a four-level scale. By means of pathologic correlation, the sensitivity and positive predictive value of each sequence was calculated. TSE T2W1 and long-TE (35 msec) FLASH T2*W1 showed the highest liver-lesion CNR. The best lesion conspicuity was seen at TSE T2W1 and medium-TE (12 msec) GRE T2*W1. Short TE GRE T2*W1 showed the least imaging artifacts. The four sequences which demonstrated the best sensitivity were medium-TE (12 msec), GRE T2*W1 (FLASH, 84%; FISP, 82%), TSE W2T1 (79%), and TSE PDWI (76%). All nine sequences showed overall high positive predictive value (86-97%), with no statistically significant difference (p>0.05). In terms of image quality and the detection of sensitivity, TSE T2W1 and medium TE (12 msec) GRE T2*W1 were the top two pulse sequences among the various sequences used for no SPIO-enhanced MRI. They are thus considered to be optimal sequences for evaluating multiple malignant hepatic tumors

  4. SEGMENTATION OF ENVIRONMENTAL TIME LAPSE IMAGE SEQUENCES FOR THE DETERMINATION OF SHORE LINES CAPTURED BY HAND-HELD SMARTPHONE CAMERAS

    Directory of Open Access Journals (Sweden)

    M. Kröhnert

    2017-09-01

    Full Text Available The relevance of globally environmental issues gains importance since the last years with still rising trends. Especially disastrous floods may cause in serious damage within very short times. Although conventional gauging stations provide reliable information about prevailing water levels, they are highly cost-intensive and thus just sparsely installed. Smartphones with inbuilt cameras, powerful processing units and low-cost positioning systems seem to be very suitable wide-spread measurement devices that could be used for geo-crowdsourcing purposes. Thus, we aim for the development of a versatile mobile water level measurement system to establish a densified hydrological network of water levels with high spatial and temporal resolution. This paper addresses a key issue of the entire system: the detection of running water shore lines in smartphone images. Flowing water never appears equally in close-range images even if the extrinsics remain unchanged. Its non-rigid behavior impedes the use of good practices for image segmentation as a prerequisite for water line detection. Consequently, we use a hand-held time lapse image sequence instead of a single image that provides the time component to determine a spatio-temporal texture image. Using a region growing concept, the texture is analyzed for immutable shore and dynamic water areas. Finally, the prevalent shore line is examined by the resultant shapes. For method validation, various study areas are observed from several distances covering urban and rural flowing waters with different characteristics. Future work provides a transformation of the water line into object space by image-to-geometry intersection.

  5. Inter-slice bidirectional registration-based segmentation of the prostate gland in MR and CT image sequences

    Energy Technology Data Exchange (ETDEWEB)

    Khalvati, Farzad, E-mail: farzad.khalvati@uwaterloo.ca; Tizhoosh, Hamid R. [Department of Systems Design Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Salmanpour, Aryan; Rahnamayan, Shahryar [Department of Engineering and Applied Science, University of Ontario Institute of Technology, Oshawa, Ontario L1H 7K4 (Canada); Rodrigues, George [Department of Radiation Oncology, London Regional Cancer Program, London, Ontario N6C 2R6, Canada and Department of Epidemiology/Biostatistics, University of Western Ontario, London, Ontario N6A 3K7 (Canada)

    2013-12-15

    Purpose: Accurate segmentation and volume estimation of the prostate gland in magnetic resonance (MR) and computed tomography (CT) images are necessary steps in diagnosis, treatment, and monitoring of prostate cancer. This paper presents an algorithm for the prostate gland volume estimation based on the semiautomated segmentation of individual slices in T2-weighted MR and CT image sequences. Methods: The proposedInter-Slice Bidirectional Registration-based Segmentation (iBRS) algorithm relies on interslice image registration of volume data to segment the prostate gland without the use of an anatomical atlas. It requires the user to mark only three slices in a given volume dataset, i.e., the first, middle, and last slices. Next, the proposed algorithm uses a registration algorithm to autosegment the remaining slices. We conducted comprehensive experiments to measure the performance of the proposed algorithm using three registration methods (i.e., rigid, affine, and nonrigid techniques). Results: The results with the proposed technique were compared with manual marking using prostate MR and CT images from 117 patients. Manual marking was performed by an expert user for all 117 patients. The median accuracies for individual slices measured using the Dice similarity coefficient (DSC) were 92% and 91% for MR and CT images, respectively. The iBRS algorithm was also evaluated regarding user variability, which confirmed that the algorithm was robust to interuser variability when marking the prostate gland. Conclusions: The proposed algorithm exploits the interslice data redundancy of the images in a volume dataset of MR and CT images and eliminates the need for an atlas, minimizing the computational cost while producing highly accurate results which are robust to interuser variability.

  6. Segmentation of Environmental Time Lapse Image Sequences for the Determination of Shore Lines Captured by Hand-Held Smartphone Cameras

    Science.gov (United States)

    Kröhnert, M.; Meichsner, R.

    2017-09-01

    The relevance of globally environmental issues gains importance since the last years with still rising trends. Especially disastrous floods may cause in serious damage within very short times. Although conventional gauging stations provide reliable information about prevailing water levels, they are highly cost-intensive and thus just sparsely installed. Smartphones with inbuilt cameras, powerful processing units and low-cost positioning systems seem to be very suitable wide-spread measurement devices that could be used for geo-crowdsourcing purposes. Thus, we aim for the development of a versatile mobile water level measurement system to establish a densified hydrological network of water levels with high spatial and temporal resolution. This paper addresses a key issue of the entire system: the detection of running water shore lines in smartphone images. Flowing water never appears equally in close-range images even if the extrinsics remain unchanged. Its non-rigid behavior impedes the use of good practices for image segmentation as a prerequisite for water line detection. Consequently, we use a hand-held time lapse image sequence instead of a single image that provides the time component to determine a spatio-temporal texture image. Using a region growing concept, the texture is analyzed for immutable shore and dynamic water areas. Finally, the prevalent shore line is examined by the resultant shapes. For method validation, various study areas are observed from several distances covering urban and rural flowing waters with different characteristics. Future work provides a transformation of the water line into object space by image-to-geometry intersection.

  7. Inter-slice bidirectional registration-based segmentation of the prostate gland in MR and CT image sequences

    International Nuclear Information System (INIS)

    Khalvati, Farzad; Tizhoosh, Hamid R.; Salmanpour, Aryan; Rahnamayan, Shahryar; Rodrigues, George

    2013-01-01

    Purpose: Accurate segmentation and volume estimation of the prostate gland in magnetic resonance (MR) and computed tomography (CT) images are necessary steps in diagnosis, treatment, and monitoring of prostate cancer. This paper presents an algorithm for the prostate gland volume estimation based on the semiautomated segmentation of individual slices in T2-weighted MR and CT image sequences. Methods: The proposedInter-Slice Bidirectional Registration-based Segmentation (iBRS) algorithm relies on interslice image registration of volume data to segment the prostate gland without the use of an anatomical atlas. It requires the user to mark only three slices in a given volume dataset, i.e., the first, middle, and last slices. Next, the proposed algorithm uses a registration algorithm to autosegment the remaining slices. We conducted comprehensive experiments to measure the performance of the proposed algorithm using three registration methods (i.e., rigid, affine, and nonrigid techniques). Results: The results with the proposed technique were compared with manual marking using prostate MR and CT images from 117 patients. Manual marking was performed by an expert user for all 117 patients. The median accuracies for individual slices measured using the Dice similarity coefficient (DSC) were 92% and 91% for MR and CT images, respectively. The iBRS algorithm was also evaluated regarding user variability, which confirmed that the algorithm was robust to interuser variability when marking the prostate gland. Conclusions: The proposed algorithm exploits the interslice data redundancy of the images in a volume dataset of MR and CT images and eliminates the need for an atlas, minimizing the computational cost while producing highly accurate results which are robust to interuser variability

  8. Detection of Subarachnoid Hemorrhage at Acute and Subacute/Chronic Stages: Comparison of Four Magnetic Resonance Imaging Pulse Sequences and Computed Tomography

    Directory of Open Access Journals (Sweden)

    Mei-Kang Yuan

    2005-03-01

    Conclusion: FLAIR and GE T2* MRI pulse sequences, and CT scans, are all statistically significant indicators of acute SAH. GE T2*-weighted images are statistically significant indicators of subacute-to-chronic SAH, whereas other MRI pulse sequences, and CT scans, are not.

  9. DIfferential Subsampling with Cartesian Ordering (DISCO): a high spatio-temporal resolution Dixon imaging sequence for multiphasic contrast enhanced abdominal imaging.

    Science.gov (United States)

    Saranathan, Manojkumar; Rettmann, Dan W; Hargreaves, Brian A; Clarke, Sharon E; Vasanawala, Shreyas S

    2012-06-01

    To develop and evaluate a multiphasic contrast-enhanced MRI method called DIfferential Sub-sampling with Cartesian Ordering (DISCO) for abdominal imaging. A three-dimensional, variable density pseudo-random k-space segmentation scheme was developed and combined with a Dixon-based fat-water separation algorithm to generate high temporal resolution images with robust fat suppression and without compromise in spatial resolution or coverage. With institutional review board approval and informed consent, 11 consecutive patients referred for abdominal MRI at 3 Tesla (T) were imaged with both DISCO and a routine clinical three-dimensional SPGR-Dixon (LAVA FLEX) sequence. All images were graded by two radiologists using quality of fat suppression, severity of artifacts, and overall image quality as scoring criteria. For assessment of arterial phase capture efficiency, the number of temporal phases with angiographic phase and hepatic arterial phase was recorded. There were no significant differences in quality of fat suppression, artifact severity or overall image quality between DISCO and LAVA FLEX images (P > 0.05, Wilcoxon signed rank test). The angiographic and arterial phases were captured in all 11 patients scanned using the DISCO acquisition (mean number of phases were two and three, respectively). DISCO effectively captures the fast dynamics of abdominal pathology such as hyperenhancing hepatic lesions with a high spatio-temporal resolution. Typically, 1.1 × 1.5 × 3 mm spatial resolution over 60 slices was achieved with a temporal resolution of 4-5 s. Copyright © 2012 Wiley Periodicals, Inc.

  10. Breast MRI at very short TE (minTE). Image analysis of minTE sequences on non-fat-saturated, subtracted T1-weighted images

    International Nuclear Information System (INIS)

    Wenkel, Evelyn; Janka, Rolf; Kaemmerer, Nadine; Uder, Michael; Hammon, Matthias; Brand, Michael; Hartmann, Arndt

    2017-01-01

    The aim was to evaluate a minimum echo time (minTE) protocol for breast magnetic resonance imaging (MRI) in patients with breast lesions compared to a standard TE (nTE) time protocol. Breasts of 144 women were examined with a 1.5 Tesla MRI scanner. Additionally to the standard gradient-echo sequence with nTE (4.8 ms), a variant with minimum TE (1.2 ms) was used in an interleaved fashion which leads to a better temporal resolution and should reduce the scan time by approximately 50%. Lesion sizes were measured and the signal-to-noise ratio (SNR) as well as the contrast-to-noise ratio (CNR) were calculated. Subjective confidence was evaluated using a 3-point scale before looking at the nTE sequences (1 = very sure that I can identify a lesion and classify it, 2 = quite sure that I can identify a lesion and classify it, 3 = definitely want to see nTE for final assessment) and the subjective image quality of all examinations was evaluated using a four-grade scale (1 = sharp, 2 = slight blur, 3 = moderate blur and 4 = severe blur/not evaluable) for lesion and skin sharpness. Lesion morphology and contrast enhancement were also evaluated. With minTE sequences, no lesion was rated with ''definitely want to see nTE sequences for final assessment''. The difference of the longitudinal and transverse diameter did not differ significantly (p>0.05). With minTE, lesions and skin were rated to be significantly more blurry (p<0.01 for lesions and p<0.05 for skin). There was no difference between both sequences with respect to SNR, CNR, lesion morphology, contrast enhancement and detection of multifocal disease. Dynamic breast MRI with a minTE protocol is feasible without a major loss of information (SNR, CNR, lesion morphology, contrast enhancement and lesion sizes) and the temporal resolution can be increased by a factor of 2 using minTE sequences.

  11. Breast MRI at very short TE (minTE). Image analysis of minTE sequences on non-fat-saturated, subtracted T1-weighted images

    Energy Technology Data Exchange (ETDEWEB)

    Wenkel, Evelyn; Janka, Rolf; Kaemmerer, Nadine; Uder, Michael; Hammon, Matthias; Brand, Michael [Univ. Hospital Erlangen (Germany). Dept. of Radiology; Geppert, Christian [Siemens Healthcare GmbH, Erlangen (Germany); Hartmann, Arndt [Univ. Hospital Erlangen (Germany). Dept. of Pathology

    2017-02-15

    The aim was to evaluate a minimum echo time (minTE) protocol for breast magnetic resonance imaging (MRI) in patients with breast lesions compared to a standard TE (nTE) time protocol. Breasts of 144 women were examined with a 1.5 Tesla MRI scanner. Additionally to the standard gradient-echo sequence with nTE (4.8 ms), a variant with minimum TE (1.2 ms) was used in an interleaved fashion which leads to a better temporal resolution and should reduce the scan time by approximately 50%. Lesion sizes were measured and the signal-to-noise ratio (SNR) as well as the contrast-to-noise ratio (CNR) were calculated. Subjective confidence was evaluated using a 3-point scale before looking at the nTE sequences (1 = very sure that I can identify a lesion and classify it, 2 = quite sure that I can identify a lesion and classify it, 3 = definitely want to see nTE for final assessment) and the subjective image quality of all examinations was evaluated using a four-grade scale (1 = sharp, 2 = slight blur, 3 = moderate blur and 4 = severe blur/not evaluable) for lesion and skin sharpness. Lesion morphology and contrast enhancement were also evaluated. With minTE sequences, no lesion was rated with ''definitely want to see nTE sequences for final assessment''. The difference of the longitudinal and transverse diameter did not differ significantly (p>0.05). With minTE, lesions and skin were rated to be significantly more blurry (p<0.01 for lesions and p<0.05 for skin). There was no difference between both sequences with respect to SNR, CNR, lesion morphology, contrast enhancement and detection of multifocal disease. Dynamic breast MRI with a minTE protocol is feasible without a major loss of information (SNR, CNR, lesion morphology, contrast enhancement and lesion sizes) and the temporal resolution can be increased by a factor of 2 using minTE sequences.

  12. Attenuation values of renal parenchyma in virtual noncontrast images acquired from multiphase renal dual-energy CT: Comparison with standard noncontrast CT.

    Science.gov (United States)

    Lin, Yuan-Mao; Chiou, Yi-You; Wu, Mei-Han; Huang, Shan-Su; Shen, Shu-Huei

    2018-04-01

    To compare the renal parenchyma attenuation of virtual noncontrast (VNC) images derived from multiphase renal dual-energy computed tomography (DECT) with standard noncontrast (SNC) images, and to determine the optimum phase for VNC images. Twenty-nine men and 16 women (mean age, 61 ± 13 years; range, 37-89 years) underwent dynamic renal DECT (100/Sn140 kVp) were included in this institutional review board-approved retrospective study. There were four phases of the scan, which included noncontrast, corticomedullary (CMP), nephrographic (NP), and excretory phases (EP). The VNC images was generated from CMP, NP and EP. CT numbers of SNC images and VNC images of each phases were measured in the renal cortex and medulla. Mean standard deviation of subcutaneous fat was measured as image noise on SNC and VNC images. Radiation dose was recorded and potential radiation dose reduction was estimated. Results were tested for statistical significance using the unpaired t-test and agreement using Bland-Altman plot analysis. The difference in mean attenuation between SNC and each phase of VNC images were ≤4 HU. The mean attenuation of renal cortex and medulla was 33.2 ± 4.4 HU, and 34.2 ± 4.8 HU in SNC, 33.6 ± 7.6 HU and 31.1 ± 8.3 HU in VNC of CMP, 34.8 ± 8.6 HU and 35.6 ± 8.5 HU in VNC of NP, 31.5 ± 7.6 HU and 32.4 ± 7.5 HU in VNC of EP. In VNC of CMP, the attenuation of the cortex was higher than the medulla (p VNC of NP, the attenuation of renal cortex was higher than SNC (p VNC of EP, the attenuation of cortex and medulla were lower than SNC (p VNC images from multiphase renal DECT were similar to SNC images. Using the nephrographic phase can gives more comparable VNC images to SNC images in renal parenchyma than other phases. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. Motion tracking and electromyography assist the removal of mirror hand contributions to fNIRS images acquired during a finger tapping task performed by children with cerebral palsy

    Science.gov (United States)

    Hervey, Nathan; Khan, Bilal; Shagman, Laura; Tian, Fenghua; Delgado, Mauricio R.; Tulchin-Francis, Kirsten; Shierk, Angela; Smith, Linsley; Reid, Dahlia; Clegg, Nancy J.; Liu, Hanli; MacFarlane, Duncan; Alexandrakis, George

    2013-03-01

    Functional neurological imaging has been shown to be valuable in evaluating brain plasticity in children with cerebral palsy (CP). In recent studies it has been demonstrated that functional near-infrared spectroscopy (fNIRS) is a viable and sensitive method for imaging motor cortex activities in children with CP. However, during unilateral finger tapping tasks children with CP often exhibit mirror motions (unintended motions in the non-tapping hand), and current fNIRS image formation techniques do not account for this. Therefore, the resulting fNIRS images contain activation from intended and unintended motions. In this study, cortical activity was mapped with fNIRS on four children with CP and five controls during a finger tapping task. Finger motion and arm muscle activation were concurrently measured using motion tracking cameras and electromyography (EMG). Subject-specific regressors were created from motion capture and EMG data and used in a general linear model (GLM) analysis in an attempt to create fNIRS images representative of different motions. The analysis provided an fNIRS image representing activation due to motion and muscle activity for each hand. This method could prove to be valuable in monitoring brain plasticity in children with CP by providing more consistent images between measurements. Additionally, muscle effort versus cortical effort was compared between control and CP subjects. More cortical effort was required to produce similar muscle effort in children with CP. It is possible this metric could be a valuable diagnostic tool in determining response to treatment.

  14. Identification Of Barley Grain Mycoflora By Next Generation Sequencing And Videometer Multispectral Imaging

    DEFF Research Database (Denmark)

    Jørgensen, Johannes Ravn; Carstensen, Jens Michael; Søren, Knudsen

    ) in the reflectance mode (5 Mpix per band, pixel size app. 45 μm x 45 μm). Spectral information over the surface of seeds may be combined with information about size, shape, and texture of the seeds. This information links detection of fungal infection with other seed characteristics known from general seed testing...... species in the genus produce mycotoxins responsible for serious quality deterioration. In malting barley, Fusarium also has a negative effect by causing gushing in beer. A number of barley seeds (app. 200) assumed to be infected by fungal from different origins and years of cultivation were tested by NGS...... sequencing the ITS (Internal Transcribed Spacer) region from total DNA. Approximately 2-4000 sequences were obtained from each seed and these were subsequently identified to species level in order to give an exact identification of fungal genera on each seed. The main fungal genera identified were Fusarium...

  15. Magnetic resonance imaging of metal artifact reduction sequences in the assessment of metal-on-metal hip prostheses

    Directory of Open Access Journals (Sweden)

    Aboelmagd SM

    2014-05-01

    Full Text Available Sharief M Aboelmagd, Paul N Malcolm, Andoni P Toms Department of Radiology, Norfolk and Norwich University Hospital National Health Service Trust, Norwich, UK Abstract: Recent developments in metal artifact reduction techniques in magnetic resonance (MR have, in large part, been stimulated by the advent of soft tissue complications associated with modern metal-on-metal total hip replacements. Metallic orthopedic implants can result in severe degradation of MR images because ferromagnetic susceptibility causes signal loss, signal pile-up, geometric distortion, and failure of fat suppression. There are several approaches to controlling these susceptibility artifacts. Standard fast spin echo sequences can be adapted by modifying echo times, matrix, receiver bandwidth, slice thickness, and echo trains to minimize frequency encoding misregistration. Short tau inversion recovery and 2-point Dixon techniques are both more resistant to susceptibility artifacts than spectral fat suppression. A number of dedicated metal artifact reduction sequences are now available commercially. The common approach of these multispectral techniques is to generate three dimensional datasets from which the final images are reconstructed. Frequency encoding misregistration is controlled using a variety of techniques, including specific resonant frequency acquisition, view-angle tilting, and phase encoding. Metal artifact reduction MR imaging has been the key to understanding the prevalence, severity, and prognosis of adverse reactions to metal debris in metal-on-metal hip replacements. Conventional radiographs are typically normal or demonstrate minimal change and are unable to demonstrate the often extensive soft tissue abnormalities, which include necrosis, soft tissue masses and fluid collections, myositis, muscle atrophy, tendon avulsions, and osteonecrosis. These MR findings correlate poorly with clinical and serological measures of disease, and therefore MR imaging is

  16. Automatic classification of minimally invasive instruments based on endoscopic image sequences

    Science.gov (United States)

    Speidel, Stefanie; Benzko, Julia; Krappe, Sebastian; Sudra, Gunther; Azad, Pedram; Müller-Stich, Beat Peter; Gutt, Carsten; Dillmann, Rüdiger

    2009-02-01

    Minimally invasive surgery is nowadays a frequently applied technique and can be regarded as a major breakthrough in surgery. The surgeon has to adopt special operation-techniques and deal with difficulties like the complex hand-eye coordination and restricted mobility. To alleviate these constraints we propose to enhance the surgeon's capabilities by providing a context-aware assistance using augmented reality techniques. To analyze the current situation for context-aware assistance, we need intraoperatively gained sensor data and a model of the intervention. A situation consists of information about the performed activity, the used instruments, the surgical objects, the anatomical structures and defines the state of an intervention for a given moment in time. The endoscopic images provide a rich source of information which can be used for an image-based analysis. Different visual cues are observed in order to perform an image-based analysis with the objective to gain as much information as possible about the current situation. An important visual cue is the automatic recognition of the instruments which appear in the scene. In this paper we present the classification of minimally invasive instruments using the endoscopic images. The instruments are not modified by markers. The system segments the instruments in the current image and recognizes the instrument type based on three-dimensional instrument models.

  17. Fully automated motion correction in first-pass myocardial perfusion MR image sequences.

    Science.gov (United States)

    Milles, Julien; van der Geest, Rob J; Jerosch-Herold, Michael; Reiber, Johan H C; Lelieveldt, Boudewijn P F

    2008-11-01

    This paper presents a novel method for registration of cardiac perfusion magnetic resonance imaging (MRI). The presented method is capable of automatically registering perfusion data, using independent component analysis (ICA) to extract physiologically relevant features together with their time-intensity behavior. A time-varying reference image mimicking intensity changes in the data of interest is computed based on the results of that ICA. This reference image is used in a two-pass registration framework. Qualitative and quantitative validation of the method is carried out using 46 clinical quality, short-axis, perfusion MR datasets comprising 100 images each. Despite varying image quality and motion patterns in the evaluation set, validation of the method showed a reduction of the average right ventricle (LV) motion from 1.26+/-0.87 to 0.64+/-0.46 pixels. Time-intensity curves are also improved after registration with an average error reduced from 2.65+/-7.89% to 0.87+/-3.88% between registered data and manual gold standard. Comparison of clinically relevant parameters computed using registered data and the manual gold standard show a good agreement. Additional tests with a simulated free-breathing protocol showed robustness against considerable deviations from a standard breathing protocol. We conclude that this fully automatic ICA-based method shows an accuracy, a robustness and a computation speed adequate for use in a clinical environment.

  18. Clinical evaluation of fat suppressed fast-SPGR sequence of the breast MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Mitsuyuki; Hasegawa, Makoto; Matsubara, Tadashi [Yokohama Sakae Kyosai Hospital (Japan)

    1998-05-01

    MR-mammography by fat suppressed Fast-SPGR was evaluated for diagnosis and determination of invasion of tumor. Dynamic MRIs were performed in 12 phases, such as, before infusion of contrast media, right after and one to ten minutes after infusion with interval of one minute. In 15 patients (breast cancer, fibroadenoma, lymphocytic lobulitits and cystic intraductal papilloma), underwent MRI, the images were compared with pathological findings. Ten cases were confirmed as malignancy among 11 cases of breast cancer (sensitivity 91%). Eleven cases were confirmed as breast cancer among 12 cases diagnosed as breast cancer by MRI (specificity 92%). In 12 of all 15 cases, benignity or malignancy was checked correctly (accuracy 80%). Invasion of breast cancer was defined as the deep color dyeing area which was neighbored with the tumor in early stage of cystography. Eight of 11 cases were diagnosed precisely with fat suppression image, and nine were by subtraction image. Diagnosis was possible only by subtraction image in a case of scirrhous carcinoma accompanied with intradutal invasion. The area of invasion was not defined correctly in the case accompanied by mastopathy. It is difficult to evaluate benignity or malignancy of mammary gland tumor only by dynamic MRI, it is necessary to diagnose the shape and deep color image of tumor generally. (K.H.)

  19. Three-dimensional gradient echo versus spin echo sequence in contrast-enhanced imaging of the pituitary gland at 3 T

    Energy Technology Data Exchange (ETDEWEB)

    Kakite, Suguru, E-mail: sugkaki@med.tottori-u.ac.jp [Division of Radiology, Department of Pathophysiological and Therapeutic Science, Faculty of Medicine, Tottori University, 36-1, Nishicho, Yonago 683-8503 (Japan); Fujii, Shinya [Division of Radiology, Department of Pathophysiological and Therapeutic Science, Faculty of Medicine, Tottori University, 36-1, Nishicho, Yonago 683-8503 (Japan); Kurosaki, Masamichi [Department of Neurosurgery, Faculty of Medicine, Tottori University, 36-1, Nishicho, Yonago 683-8503 (Japan); Kanasaki, Yoshiko; Matsusue, Eiji; Kaminou, Toshio; Ogawa, Toshihide [Division of Radiology, Department of Pathophysiological and Therapeutic Science, Faculty of Medicine, Tottori University, 36-1, Nishicho, Yonago 683-8503 (Japan)

    2011-07-15

    Introduction: To clarify whether a three-dimensional-gradient echo (3D-GRE) or spin echo (SE) sequence is more useful for evaluating sellar lesions on contrast-enhanced T1-weighted MR imaging at 3.0 Tesla (T). Methods: We retrospectively assessed contrast-enhanced T1-weighted images using 3D-GRE and SE sequences at 3.0 T obtained from 33 consecutive patients with clinically suspected sellar lesions. Two experienced neuroradiologists evaluated the images qualitatively in terms of the following criteria: boundary edge of the cavernous sinus and pituitary gland, border of sellar lesions, delineation of the optic nerve and cranial nerves within the cavernous sinus, susceptibility and flow artifacts, and overall image quality. Results: At 3.0 T, 3D-GRE provided significantly better images than the SE sequence in terms of the border of sellar lesions, delineation of cranial nerves, and overall image quality; there was no significant difference regarding the boundary edge of the cavernous sinus and pituitary gland. In addition, the 3D-GRE sequence showed fewer pulsation artifacts but more susceptibility artifacts. Conclusion: Our results indicate that 3D-GRE is the more suitable sequence for evaluating sellar lesions on contrast-enhanced T1-weighted imaging at 3.0 T.

  20. A flexible new method for 3D measurement based on multi-view image sequences

    Science.gov (United States)

    Cui, Haihua; Zhao, Zhimin; Cheng, Xiaosheng; Guo, Changye; Jia, Huayu

    2016-11-01

    Three-dimensional measurement is the base part for reverse engineering. The paper developed a new flexible and fast optical measurement method based on multi-view geometry theory. At first, feature points are detected and matched with improved SIFT algorithm. The Hellinger Kernel is used to estimate the histogram distance instead of traditional Euclidean distance, which is immunity to the weak texture image; then a new filter three-principle for filtering the calculation of essential matrix is designed, the essential matrix is calculated using the improved a Contrario Ransac filter method. One view point cloud is constructed accurately with two view images; after this, the overlapped features are used to eliminate the accumulated errors caused by added view images, which improved the camera's position precision. At last, the method is verified with the application of dental restoration CAD/CAM, experiment results show that the proposed method is fast, accurate and flexible for tooth 3D measurement.

  1. Digital systems to acquire radiological imaging. Characteristics and quality control; Sistemas digitales de adquisicion de imagenes radiograficas. Caracteristicas y Control de Calidad

    Energy Technology Data Exchange (ETDEWEB)

    Torres Cabrera, R.; Hernando Gonzalez, I.

    2006-07-01

    Due to its special characteristics, quality control in digital radiographic systems is very important, even more than in conventional film-screen systems. Differences between digital and analogical images,a in terms of dynamics range, spatial and contrast resolution, and the flexibility of data post-processing require some actions to maintain clinical images in an optimum quality level. Revision 1 of the Spanish Protocol of Quality Control in Diagnostic Radiology includes a chapter dedicated to the quality control of these digital systems for the acquisition of radiographic images. In this paper the different parameters for quality control procedures are described. Also some difficulties to be concerned about (absence of levels of tolerance, access to the raw-data images and related information, availability of use anthropomorphic phantoms, etc, etc) are noted, as well as the most significant aspects of the differences in relation to the ana logical systems. (Author) 15 refs.

  2. Self-Organization of Spatio-Temporal Hierarchy via Learning of Dynamic Visual Image Patterns on Action Sequences.

    Science.gov (United States)

    Jung, Minju; Hwang, Jungsik; Tani, Jun

    2015-01-01

    It is well known that the visual cortex efficiently processes high-dimensional spatial information by using a hierarchical structure. Recently, computational models that were inspired by the spatial hierarchy of the visual cortex have shown remarkable performance in image recognition. Up to now, however, most biological and computational modeling studies have mainly focused on the spatial domain and do not discuss temporal domain processing of the visual cortex. Several studies on the visual cortex and other brain areas associated with motor control support that the brain also uses its hierarchical structure as a processing mechanism for temporal information. Based on the success of previous computational models using spatial hierarchy and temporal hierarchy observed in the brain, the current report introduces a novel neural network model for the recognition of dynamic visual image patterns based solely on the learning of exemplars. This model is characterized by the application of both spatial and temporal constraints on local neural activities, resulting in the self-organization of a spatio-temporal hierarchy necessary for the recognition of complex dynamic visual image patterns. The evaluation with the Weizmann dataset in recognition of a set of prototypical human movement patterns showed that the proposed model is significantly robust in recognizing dynamically occluded visual patterns compared to other baseline models. Furthermore, an evaluation test for the recognition of concatenated sequences of those prototypical movement patterns indicated that the model is endowed with a remarkable capability for the contextual recognition of long-range dynamic visual image patterns.

  3. Whole-body magnetic resonance imaging for staging and follow-up of pediatric patients with Hodgkin's lymphoma: comparison of different sequences

    International Nuclear Information System (INIS)

    Nava, Daniel; Oliveira, Heverton Cesar de

    2011-01-01

    Objective: to compare the performance of the T1, T2, STIR and DWIBS (diffusion-weighted whole-body imaging with background body signal suppression) sequences in the staging and follow-up of pediatric patients with Hodgkin's lymphoma in lymph node chains, parenchymal organs and bone marrow, and to evaluate interobserver agreement. Materials and methods: the authors studied 12 patients with confirmed diagnosis of Hodgkin's lymphoma. The patients were referred for whole body magnetic resonance imaging with T1-weighted, T2-weighted, STIR and DWIBS sequences. Results: the number of lymph node sites characterized as affected by the disease on T1- and T2-weighted sequences showed similar results (8 sites for both sequences), but lower than DWIBS and STIR sequences (11 and 12 sites, respectively). The bone marrow involvement by lymphoma showed the same values for the T1-, T2-weighted and DWIBS sequences (17 lesions), higher than the value found on STIR (13 lesions). A high rate of interobserver agreement was observed as the four sequences were analyzed. Conclusion: STIR and DWIBS sequences detected the highest number of lymph node sites characterized as affected by the disease. Similar results were demonstrated by all the sequences in the evaluation of parenchymal organs and bone marrow. A high interobserver agreement was observed as the four sequences were analyzed. (author)

  4. Camera pose refinement by matching uncertain 3D building models with thermal infrared image sequences for high quality texture extraction

    Science.gov (United States)

    Iwaszczuk, Dorota; Stilla, Uwe

    2017-10-01

    Thermal infrared (TIR) images are often used to picture damaged and weak spots in the insulation of the building hull, which is widely used in thermal inspections of buildings. Such inspection in large-scale areas can be carried out by combining TIR imagery and 3D building models. This combination can be achieved via texture mapping. Automation of texture mapping avoids time consuming imaging and manually analyzing each face independently. It also provides a spatial reference for façade structures extracted in the thermal textures. In order to capture all faces, including the roofs, façades, and façades in the inner courtyard, an oblique looking camera mounted on a flying platform is used. Direct geo-referencing is usually not sufficient for precise texture extraction. In addition, 3D building models have also uncertain geometry. In this paper, therefore, methodology for co-registration of uncertain 3D building models with airborne oblique view images is presented. For this purpose, a line-based model-to-image matching is developed, in which the uncertainties of the 3D building model, as well as of the image features are considered. Matched linear features are used for the refinement of the exterior orientation parameters of the camera in order to ensure optimal co-registration. Moreover, this study investigates whether line tracking through the image sequence supports the matching. The accuracy of the extraction and the quality of the textures are assessed. For this purpose, appropriate quality measures are developed. The tests showed good results on co-registration, particularly in cases where tracking between the neighboring frames had been applied.

  5. Measurement of traffic parameters in image sequence using spatio-temporal information

    International Nuclear Information System (INIS)

    Lee, Daeho; Park, Youngtae

    2008-01-01

    This paper proposes a novel method for measurement of traffic parameters, such as the number of passed vehicles, velocity and occupancy rate, by video image analysis. The method is based on a region classification followed by spatio-temporal image analysis. Local detection region images in traffic lanes are classified into one of four categories: the road, the vehicle, the reflection and the shadow, by using statistical and structural features. Misclassification at a frame is corrected by using temporally correlated features of vehicles in the spatio-temporal image. This capability of error correction results in the accurate estimation of traffic parameters even in high traffic congestion. Also headlight detection is employed for nighttime operation. Experimental results show that the accuracy is more than 94% in our test database of diverse operating conditions such as daytime, shadowy daytime, highway, urban way, rural way, rainy day, snowy day, dusk and nighttime. The average processing time is 30 ms per frame when four traffic lanes are processed, and real-time operation could be realized while ensuring robust detection performance even for high-speed vehicles up to 150 km h −1

  6. Fat suppression at 2D MR imaging of the hands: Dixon method versus CHESS technique and STIR sequence

    International Nuclear Information System (INIS)

    Kirchgesner, Thomas; Perlepe, Vasiliki; Michoux, Nicolas; Larbi, Ahmed; Vande Berg, Bruno

    2017-01-01

    Highlights: • Dixon yields effective fat suppression at 2D MRI of the hands. • CHESS fat suppression is less effective especially in the coronal plane. • SNR is higher with Dixon than with CHESS at T1-weighted MR imaging. • SNR is higher with CHESS than with Dixon and STIR at T2-weighted MR imaging. - Abstract: Objective: To compare the effectiveness of fat suppression and the signal-to-noise ratio (SNR) of the Dixon method with those of the CHESS (Chemical Shift-Selective) technique and STIR (Short Tau Inversion Recovery) sequence in hands of normal subjects at 2D MR imaging. Material and methods: 14 healthy volunteers (mean age of 29.4 years) consented to have both hands prospectively imaged with SE T1 Dixon, T1 CHESS, T2 Dixon, T2 CHESS and STIR sequences in a 1.5T MR scanner. Three radiologists scored the effectiveness of fat suppression in bone marrow (EFS BM ) and soft tissues (EFS ST ) in 20 joints per subject. One radiologist measured the SNR in 10 bones per subject. Statistical analysis used two-way ANOVA with random effects, paired t-test and observed agreement to assess differences in effectiveness of fat suppression, differences in SNR and inter-observer agreement. Results: EFS BM was statistically significantly higher for T1 Dixon than for T1 CHESS and for T2 Dixon than for T2 CHESS (p < 0.0001). EFS BM was significantly higher for T2 Dixon than for STIR in the coronal plane (p = 0.0020). The SNR was significantly higher for T1 Dixon than for T1 CHESS and for T2 Dixon than for STIR (p < 0.0001). The SNR was significantly lower for T2 Dixon than for T2 CHESS (p < 0.0001). Conclusion: The Dixon method yields more effective fat suppression and higher SNR than the CHESS technique at 2D T1-weighted MR imaging of the hands. At T2-weighted MR imaging, fat suppression is more effective with the Dixon method while SNR is higher with the CHESS technique.

  7. Fat suppression at 2D MR imaging of the hands: Dixon method versus CHESS technique and STIR sequence

    Energy Technology Data Exchange (ETDEWEB)

    Kirchgesner, Thomas, E-mail: Thomas.Kirchgesner@uclouvain.be; Perlepe, Vasiliki, E-mail: Vasiliki.Perlepe@uclouvain.be; Michoux, Nicolas, E-mail: Nicolas.Michoux@uclouvain.be; Larbi, Ahmed, E-mail: Ahmed.Larbi@chu-nimes.fr; Vande Berg, Bruno, E-mail: Bruno.VandeBerg@uclouvain.be

    2017-04-15

    Highlights: • Dixon yields effective fat suppression at 2D MRI of the hands. • CHESS fat suppression is less effective especially in the coronal plane. • SNR is higher with Dixon than with CHESS at T1-weighted MR imaging. • SNR is higher with CHESS than with Dixon and STIR at T2-weighted MR imaging. - Abstract: Objective: To compare the effectiveness of fat suppression and the signal-to-noise ratio (SNR) of the Dixon method with those of the CHESS (Chemical Shift-Selective) technique and STIR (Short Tau Inversion Recovery) sequence in hands of normal subjects at 2D MR imaging. Material and methods: 14 healthy volunteers (mean age of 29.4 years) consented to have both hands prospectively imaged with SE T1 Dixon, T1 CHESS, T2 Dixon, T2 CHESS and STIR sequences in a 1.5T MR scanner. Three radiologists scored the effectiveness of fat suppression in bone marrow (EFS{sup BM}) and soft tissues (EFS{sup ST}) in 20 joints per subject. One radiologist measured the SNR in 10 bones per subject. Statistical analysis used two-way ANOVA with random effects, paired t-test and observed agreement to assess differences in effectiveness of fat suppression, differences in SNR and inter-observer agreement. Results: EFS{sup BM} was statistically significantly higher for T1 Dixon than for T1 CHESS and for T2 Dixon than for T2 CHESS (p < 0.0001). EFS{sup BM} was significantly higher for T2 Dixon than for STIR in the coronal plane (p = 0.0020). The SNR was significantly higher for T1 Dixon than for T1 CHESS and for T2 Dixon than for STIR (p < 0.0001). The SNR was significantly lower for T2 Dixon than for T2 CHESS (p < 0.0001). Conclusion: The Dixon method yields more effective fat suppression and higher SNR than the CHESS technique at 2D T1-weighted MR imaging of the hands. At T2-weighted MR imaging, fat suppression is more effective with the Dixon method while SNR is higher with the CHESS technique.

  8. Fully automatic registration and segmentation of first-pass myocardial perfusion MR image sequences.

    Science.gov (United States)

    Gupta, Vikas; Hendriks, Emile A; Milles, Julien; van der Geest, Rob J; Jerosch-Herold, Michael; Reiber, Johan H C; Lelieveldt, Boudewijn P F

    2010-11-01

    Derivation of diagnostically relevant parameters from first-pass myocardial perfusion magnetic resonance images involves the tedious and time-consuming manual segmentation of the myocardium in a large number of images. To reduce the manual interaction and expedite the perfusion analysis, we propose an automatic registration and segmentation method for the derivation of perfusion linked parameters. A complete automation was accomplished by first registering misaligned images using a method based on independent component analysis, and then using the registered data to automatically segment the myocardium with active appearance models. We used 18 perfusion studies (100 images per study) for validation in which the automatically obtained (AO) contours were compared with expert drawn contours on the basis of point-to-curve error, Dice index, and relative perfusion upslope in the myocardium. Visual inspection revealed successful segmentation in 15 out of 18 studies. Comparison of the AO contours with expert drawn contours yielded 2.23 ± 0.53 mm and 0.91 ± 0.02 as point-to-curve error and Dice index, respectively. The average difference between manually and automatically obtained relative upslope parameters was found to be statistically insignificant (P = .37). Moreover, the analysis time per slice was reduced from 20 minutes (manual) to 1.5 minutes (automatic). We proposed an automatic method that significantly reduced the time required for analysis of first-pass cardiac magnetic resonance perfusion images. The robustness and accuracy of the proposed method were demonstrated by the high spatial correspondence and statistically insignificant difference in perfusion parameters, when AO contours were compared with expert drawn contours. Copyright © 2010 AUR. Published by Elsevier Inc. All rights reserved.

  9. Fat-Suppressed T2 Sequences for Routine 3.0-Tesla Lumbar Spine Magnetic Resonance Imaging: A Preliminary Report

    Energy Technology Data Exchange (ETDEWEB)

    McKinney, A. M.; Gadani, S.; Palmer, C. S.; Vidarsson, L. (Dept. of Radiology, Hennepin County and Univ. of Minnesota Medical Centers, Minneapolis, MN (United States))

    2008-09-15

    Background: Clear depiction of the ligamentum flavum on routine lumbar magnetic resonance imaging (MRI) is essential in accurately describing the extent of degenerative disease. In routine, noncontrast evaluations, focal fatty deposition or hemangiomas can be difficult to distinguish from malignant foci on fast spin-echo (FSE) T2-weighted images. Purpose: To describe the use of T2 fast field echo (T2FFE) in combination with spectral presaturation inversion recovery (SPIR) fat suppression for noncontrast, routine lumbar spine outpatient MR imaging at 3.0 Tesla (3T). Material and Methods: An axial gradient echo (GE) T2FFE sequence was combined with SPIR fat suppression (T2FFE-SPIR), via a 3T Philips Intera (Philips Medical Systems, Best, The Netherlands) scanner, and added to the routine, noncontrast lumbar MRI examinations, which included sagittal FSE T1-weighted (T1WI), T2-weighted (T2WI), short-tau inversion recovery (STIR), and axial FSE T2WI. The sequence was performed in over 500 patients over a 1-year period, without intravenous contrast, and with slice thickness and planes of section identical to the axial FSE T1WI and T2WI images. The sequence typically lasted about 4.5-6 min. Results: The use of T2FFE-SPIR enabled visualization of the ligamentum flavum in degenerative disease, and the exclusion of focal fatty lesions on FSE T2WI. Other benefits included: the identification of malignant foci, the uncommon detection of hemorrhage, and the elimination of spurious flow voids. Several brief examples are provided to demonstrate the utility of this technique. Conclusion: The addition of T2FFE-SPIR to routine, noncontrast protocols in outpatients could provide further confidence in the visualization of the ligamentum flavum in degenerative disease, and can exclude malignancy in T2-bright areas of focal fatty marrow. Larger studies would be helpful to evaluate the accuracy of this technique versus FSE techniques in depicting degenerative, malignant, or inflammatory

  10. Fat-Suppressed T2* Sequences for Routine 3.0-Tesla Lumbar Spine Magnetic Resonance Imaging: A Preliminary Report

    International Nuclear Information System (INIS)

    McKinney, A. M.; Gadani, S.; Palmer, C. S.; Vidarsson, L.

    2008-01-01

    Background: Clear depiction of the ligamentum flavum on routine lumbar magnetic resonance imaging (MRI) is essential in accurately describing the extent of degenerative disease. In routine, noncontrast evaluations, focal fatty deposition or hemangiomas can be difficult to distinguish from malignant foci on fast spin-echo (FSE) T2-weighted images. Purpose: To describe the use of T2* fast field echo (T2FFE) in combination with spectral presaturation inversion recovery (SPIR) fat suppression for noncontrast, routine lumbar spine outpatient MR imaging at 3.0 Tesla (3T). Material and Methods: An axial gradient echo (GE) T2FFE sequence was combined with SPIR fat suppression (T2FFE-SPIR), via a 3T Philips Intera (Philips Medical Systems, Best, The Netherlands) scanner, and added to the routine, noncontrast lumbar MRI examinations, which included sagittal FSE T1-weighted (T1WI), T2-weighted (T2WI), short-tau inversion recovery (STIR), and axial FSE T2WI. The sequence was performed in over 500 patients over a 1-year period, without intravenous contrast, and with slice thickness and planes of section identical to the axial FSE T1WI and T2WI images. The sequence typically lasted about 4.5-6 min. Results: The use of T2FFE-SPIR enabled visualization of the ligamentum flavum in degenerative disease, and the exclusion of focal fatty lesions on FSE T2WI. Other benefits included: the identification of malignant foci, the uncommon detection of hemorrhage, and the elimination of spurious flow voids. Several brief examples are provided to demonstrate the utility of this technique. Conclusion: The addition of T2FFE-SPIR to routine, noncontrast protocols in outpatients could provide further confidence in the visualization of the ligamentum flavum in degenerative disease, and can exclude malignancy in T2-bright areas of focal fatty marrow. Larger studies would be helpful to evaluate the accuracy of this technique versus FSE techniques in depicting degenerative, malignant, or inflammatory

  11. Prognostic value of gradient echo T2* sequences for brain MR imaging in preterm infants

    International Nuclear Information System (INIS)

    Bruine, Francisca T. de; Berg-Huysmans, Annette A. van den; Buchem, Mark A. van; Grond, Jeroen van der; Steggerda, Sylke J.; Leijser, Lara M.; Rijken, Monique; Wezel-Meijler, Gerda van

    2014-01-01

    Gradient echo T2*-W sequences are more sensitive than T2-W spin-echo sequences for detecting hemorrhages in the brain. The aim of this study is to correlate presence of hemosiderin deposits in the brain of very preterm infants (gestational age 6 non-hemorrhagic punctate white matter lesions (PWML), cysts and/or ventricular dilatation. Six infants with post-hemorrhagic ventricular dilatation detected by US in the neonatal period were excluded. Infants were seen for follow-up at 2 years. Univariate and regression analysis assessed the relation between presence and location of hemosiderin, white matter injury and neurodevelopmental outcome. In 38/95 (40%) of the infants, hemosiderin was detected. Twenty percent (19/95) of the infants were lost to follow-up. There was a correlation between hemosiderin in the ventricular wall with >6 PWML (P < 0.001) and cysts (P < 0.001) at term-equivalent age, and with a lower psychomotor development index (PDI) (P=0.02) at 2 years. After correcting for known confounders (gestational age, gender, intrauterine growth retardation and white matter injury), the correlation with PDI was no longer significant. The clinical importance of detecting small hemosiderin deposits is limited as there is no independent association with neurodevelopmental outcome. (orig.)

  12. Micro-motion Recognition of Spatial Cone Target Based on ISAR Image Sequences

    Directory of Open Access Journals (Sweden)

    Changyong Shu

    2016-04-01

    Full Text Available The accurate micro-motions recognition of spatial cone target is the foundation of the characteristic parameter acquisition. For this reason, a micro-motion recognition method based on the distinguishing characteristics extracted from the Inverse Synthetic Aperture Radar (ISAR sequences is proposed in this paper. The projection trajectory formula of cone node strong scattering source and cone bottom slip-type strong scattering sources, which are located on the spatial cone target, are deduced under three micro-motion types including nutation, precession, and spinning, and the correctness is verified by the electromagnetic simulation. By comparison, differences are found among the projection of the scattering sources with different micro-motions, the coordinate information of the scattering sources in the Inverse Synthetic Aperture Radar sequences is extracted by the CLEAN algorithm, and the spinning is recognized by setting the threshold value of Doppler. The double observation points Interacting Multiple Model Kalman Filter is used to separate the scattering sources projection of the nutation target or precession target, and the cross point number of each scattering source’s projection track is used to classify the nutation or precession. Finally, the electromagnetic simulation data are used to verify the effectiveness of the micro-motion recognition method.

  13. Analysis of the fractal dimension of volcano geomorphology through Synthetic Aperture Radar (SAR) amplitude images acquired in C and X band.

    Science.gov (United States)

    Pepe, S.; Di Martino, G.; Iodice, A.; Manzo, M.; Pepe, A.; Riccio, D.; Ruello, G.; Sansosti, E.; Tizzani, P.; Zinno, I.

    2012-04-01

    In the last two decades several aspects relevant to volcanic activity have been analyzed in terms of fractal parameters that effectively describe natural objects geometry. More specifically, these researches have been aimed at the identification of (1) the power laws that governed the magma fragmentation processes, (2) the energy of explosive eruptions, and (3) the distribution of the associated earthquakes. In this paper, the study of volcano morphology via satellite images is dealt with; in particular, we use the complete forward model developed by some of the authors (Di Martino et al., 2012) that links the stochastic characterization of amplitude Synthetic Aperture Radar (SAR) images to the fractal dimension of the imaged surfaces, modelled via fractional Brownian motion (fBm) processes. Based on the inversion of such a model, a SAR image post-processing has been implemented (Di Martino et al., 2010), that allows retrieving the fractal dimension of the observed surfaces, dictating the distribution of the roughness over different spatial scales. The fractal dimension of volcanic structures has been related to the specific nature of materials and to the effects of active geodynamic processes. Hence, the possibility to estimate the fractal dimension from a single amplitude-only SAR image is of fundamental importance for the characterization of volcano structures and, moreover, can be very helpful for monitoring and crisis management activities in case of eruptions and other similar natural hazards. The implemented SAR image processing performs the extraction of the point-by-point fractal dimension of the scene observed by the sensor, providing - as an output product - the map of the fractal dimension of the area of interest. In this work, such an analysis is performed on Cosmo-SkyMed, ERS-1/2 and ENVISAT images relevant to active stratovolcanoes in different geodynamic contexts, such as Mt. Somma-Vesuvio, Mt. Etna, Vulcano and Stromboli in Southern Italy, Shinmoe

  14. Non-parametric Bayesian models of response function in dynamic image sequences

    Czech Academy of Sciences Publication Activity Database

    Tichý, Ondřej; Šmídl, Václav

    2016-01-01

    Roč. 151, č. 1 (2016), s. 90-100 ISSN 1077-3142 R&D Projects: GA ČR GA13-29225S Institutional support: RVO:67985556 Keywords : Response function * Blind source separation * Dynamic medical imaging * Probabilistic models * Bayesian methods Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 2.498, year: 2016 http://library.utia.cas.cz/separaty/2016/AS/tichy-0456983.pdf

  15. Bayesian Blind Separation and Deconvolution of Dynamic Image Sequences Using Sparsity Priors

    Czech Academy of Sciences Publication Activity Database

    Tichý, Ondřej; Šmídl, Václav

    2015-01-01

    Roč. 34, č. 1 (2015), s. 258-266 ISSN 0278-0062 R&D Projects: GA ČR GA13-29225S Keywords : Functional imaging * Blind source separation * Computer-aided detection and diagnosis * Probabilistic and statistical methods Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 3.756, year: 2015 http://library.utia.cas.cz/separaty/2014/AS/tichy-0431090.pdf

  16. MR diffusion weighted imaging of gastric cancer: b-value determination and comparison with routine sequences

    International Nuclear Information System (INIS)

    Zhao Xiaopeng; Tang Lei; Sun Yingshi; Li Jie; Cao Kun

    2007-01-01

    Objective: To choose the optimal b-values for the DWI of gastric cancer (GC), and investigate the value of DWI in the diagnosis of GCs. Methods: MRI examinations (T 1 WI, T 2 WI, and DWI) were performed on 31 patients with gastric cancer. Three diffusion-weighted sequences were designed with different b values, including 300 s/mm 2 (low), 600 s/mm 2 (intermediate), and 1000 s/mm 2 (high). Free water grade was used to evaluate the suppression of content in gastric lumen. Background contrast grade was used to evaluate the discriminating ability of different sequences between GC and nearby tissues. The ADCs of GCs, nearby gastric wall region, and free water in gastric lumen were measured. SNR Ca , CNR Ca-GW and SIR CaGW of high b-value DWI and routine MRI sequences were evaluated and compared. Results: The signal intensity of free water in gastric lumen decreased as b-value increased, and the SIR were 8.11± 0.77 (b=300 s/mm 2 ), 2.70±0.35 (b=600 s/mm 2 ), and 1.13±0.22 (b=1000 s/mm 2 ) (F55.368, P 2 =16.692, P 2 =9.923, P -3 mm 2 /s, (1.43±0.41) x 10 -3 mm 2 /s, and (1.18±0.25) x 10 -3 mm 2 /s; (F=12.066, P 1 WI (CNR: 12.46 vs. 2.35, Z=-3.746, P 2 WI (CNR: 12.46 vs. 3.92, Z=-3.518, P 2 ) is reasonable for DWI of GCs, which can reflect diffusion condition of water molecules more accurately, suppress signal of content in gastric lumen, and possess higher contrast. DWI can be a supplementary method of routine MRI examination for better demonstration of gastric cancers. (authors)

  17. MCTP system model based on linear programming optimization of apertures obtained from sequencing patient image data maps

    Energy Technology Data Exchange (ETDEWEB)

    Ureba, A. [Dpto. Fisiología Médica y Biofísica. Facultad de Medicina, Universidad de Sevilla, E-41009 Sevilla (Spain); Salguero, F. J. [Nederlands Kanker Instituut, Antoni van Leeuwenhoek Ziekenhuis, 1066 CX Ámsterdam, The Nederlands (Netherlands); Barbeiro, A. R.; Jimenez-Ortega, E.; Baeza, J. A.; Leal, A., E-mail: alplaza@us.es [Dpto. Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, E-41009 Sevilla (Spain); Miras, H. [Servicio de Radiofísica, Hospital Universitario Virgen Macarena, E-41009 Sevilla (Spain); Linares, R.; Perucha, M. [Servicio de Radiofísica, Hospital Infanta Luisa, E-41010 Sevilla (Spain)

    2014-08-15

    Purpose: The authors present a hybrid direct multileaf collimator (MLC) aperture optimization model exclusively based on sequencing of patient imaging data to be implemented on a Monte Carlo treatment planning system (MC-TPS) to allow the explicit radiation transport simulation of advanced radiotherapy treatments with optimal results in efficient times for clinical practice. Methods: The planning system (called CARMEN) is a full MC-TPS, controlled through aMATLAB interface, which is based on the sequencing of a novel map, called “biophysical” map, which is generated from enhanced image data of patients to achieve a set of segments actually deliverable. In order to reduce the required computation time, the conventional fluence map has been replaced by the biophysical map which is sequenced to provide direct apertures that will later be weighted by means of an optimization algorithm based on linear programming. A ray-casting algorithm throughout the patient CT assembles information about the found structures, the mass thickness crossed, as well as PET values. Data are recorded to generate a biophysical map for each gantry angle. These maps are the input files for a home-made sequencer developed to take into account the interactions of photons and electrons with the MLC. For each linac (Axesse of Elekta and Primus of Siemens) and energy beam studied (6, 9, 12, 15 MeV and 6 MV), phase space files were simulated with the EGSnrc/BEAMnrc code. The dose calculation in patient was carried out with the BEAMDOSE code. This code is a modified version of EGSnrc/DOSXYZnrc able to calculate the beamlet dose in order to combine them with different weights during the optimization process. Results: Three complex radiotherapy treatments were selected to check the reliability of CARMEN in situations where the MC calculation can offer an added value: A head-and-neck case (Case I) with three targets delineated on PET/CT images and a demanding dose-escalation; a partial breast

  18. MCTP system model based on linear programming optimization of apertures obtained from sequencing patient image data maps

    International Nuclear Information System (INIS)

    Ureba, A.; Salguero, F. J.; Barbeiro, A. R.; Jimenez-Ortega, E.; Baeza, J. A.; Leal, A.; Miras, H.; Linares, R.; Perucha, M.

    2014-01-01

    Purpose: The authors present a hybrid direct multileaf collimator (MLC) aperture optimization model exclusively based on sequencing of patient imaging data to be implemented on a Monte Carlo treatment planning system (MC-TPS) to allow the explicit radiation transport simulation of advanced radiotherapy treatments with optimal results in efficient times for clinical practice. Methods: The planning system (called CARMEN) is a full MC-TPS, controlled through aMATLAB interface, which is based on the sequencing of a novel map, called “biophysical” map, which is generated from enhanced image data of patients to achieve a set of segments actually deliverable. In order to reduce the required computation time, the conventional fluence map has been replaced by the biophysical map which is sequenced to provide direct apertures that will later be weighted by means of an optimization algorithm based on linear programming. A ray-casting algorithm throughout the patient CT assembles information about the found structures, the mass thickness crossed, as well as PET values. Data are recorded to generate a biophysical map for each gantry angle. These maps are the input files for a home-made sequencer developed to take into account the interactions of photons and electrons with the MLC. For each linac (Axesse of Elekta and Primus of Siemens) and energy beam studied (6, 9, 12, 15 MeV and 6 MV), phase space files were simulated with the EGSnrc/BEAMnrc code. The dose calculation in patient was carried out with the BEAMDOSE code. This code is a modified version of EGSnrc/DOSXYZnrc able to calculate the beamlet dose in order to combine them with different weights during the optimization process. Results: Three complex radiotherapy treatments were selected to check the reliability of CARMEN in situations where the MC calculation can offer an added value: A head-and-neck case (Case I) with three targets delineated on PET/CT images and a demanding dose-escalation; a partial breast

  19. MCTP system model based on linear programming optimization of apertures obtained from sequencing patient image data maps.

    Science.gov (United States)

    Ureba, A; Salguero, F J; Barbeiro, A R; Jimenez-Ortega, E; Baeza, J A; Miras, H; Linares, R; Perucha, M; Leal, A

    2014-08-01

    The authors present a hybrid direct multileaf collimator (MLC) aperture optimization model exclusively based on sequencing of patient imaging data to be implemented on a Monte Carlo treatment planning system (MC-TPS) to allow the explicit radiation transport simulation of advanced radiotherapy treatments with optimal results in efficient times for clinical practice. The planning system (called CARMEN) is a full MC-TPS, controlled through aMATLAB interface, which is based on the sequencing of a novel map, called "biophysical" map, which is generated from enhanced image data of patients to achieve a set of segments actually deliverable. In order to reduce the required computation time, the conventional fluence map has been replaced by the biophysical map which is sequenced to provide direct apertures that will later be weighted by means of an optimization algorithm based on linear programming. A ray-casting algorithm throughout the patient CT assembles information about the found structures, the mass thickness crossed, as well as PET values. Data are recorded to generate a biophysical map for each gantry angle. These maps are the input files for a home-made sequencer developed to take into account the interactions of photons and electrons with the MLC. For each linac (Axesse of Elekta and Primus of Siemens) and energy beam studied (6, 9, 12, 15 MeV and 6 MV), phase space files were simulated with the EGSnrc/BEAMnrc code. The dose calculation in patient was carried out with the BEAMDOSE code. This code is a modified version of EGSnrc/DOSXYZnrc able to calculate the beamlet dose in order to combine them with different weights during the optimization process. Three complex radiotherapy treatments were selected to check the reliability of CARMEN in situations where the MC calculation can offer an added value: A head-and-neck case (Case I) with three targets delineated on PET/CT images and a demanding dose-escalation; a partial breast irradiation case (Case II) solved

  20. Improved detection of sentinel lymph nodes in SPECT/CT images acquired using a low- to medium-energy general-purpose collimator.

    Science.gov (United States)

    Yoneyama, Hiroto; Tsushima, Hiroyuki; Kobayashi, Masato; Onoguchi, Masahisa; Nakajima, Kenichi; Kinuya, Seigo

    2014-01-01

    The use of the low-energy high-resolution (LEHR) collimator for lymphoscintigraphy causes the appearance of star-shaped artifacts at injection sites. The aim of this study was to confirm whether the lower resolution of the low- to medium-energy general-purpose (LMEGP) collimator is compensated by decrease in the degree of septal penetration and the reduction in star-shaped artifacts. A total of 106 female patients with breast cancer, diagnosed by biopsy, were enrolled in this study. Tc phytate (37 MBq, 1 mCi) was injected around the tumor, and planar and SPECT/CT images were obtained after 3 to 4 hours. When sentinel lymph nodes (SLNs) could not be identified from planar and SPECT/CT images by using the LEHR collimator, we repeated the study with the LMEGP collimator. Planar imaging performed using the LEHR and LEHR + LMEGP collimators positively identified SLNs in 96.2% (102/106) and 99.1% (105/106) of the patients, respectively. Using combination of planar and SPECT/CT imaging with the LEHR and LEHR + LMEGP collimators, SLNs were positively identified in 97.2% (103/106) and 100% (106/106) of the patients, respectively. The LMEGP collimator provided better results than the LEHR collimator because of the lower degree of septal penetration. The use of the LMEGP collimator improved SLN detection.

  1. Acquired bleeding disorders

    African Journals Online (AJOL)

    B one marrow aplasia ... Laboratory approach to a suspected acquired bleeding disorder. (LER = leuko- .... lymphocytic leukaemia, and lymphoma). ... cells), a bone marrow aspirate and trephine biopsy (BMAT) is not ..... transplantation.

  2. Pneumonia - children - community acquired

    Science.gov (United States)

    Bronchopneumonia - children; Community-acquired pneumonia - children; CAP - children ... Viruses are the most common cause of pneumonia in infants and children. Ways your child can get CAP include: Bacteria and viruses living in the nose, sinuses, or mouth may spread ...

  3. Real-time 3D reconstruction of road curvature in far look-ahead distance from analysis of image sequences

    Science.gov (United States)

    Behringer, Reinhold

    1995-12-01

    A system for visual road recognition in far look-ahead distance, implemented in the autonomous road vehicle VaMP (a passenger car), is described. Visual cues of a road in a video image are the bright lane markings and the edges formed at the road borders. In a distance of more than 100 m, the most relevant road cue is the homogeneous road area, limited by the two border edges. These cues can be detected by the image processing module KRONOS applying edge detection techniques and areal 2D segmentation based on resolution triangles (analogous to a resolution pyramid). An estimation process performs an update of a state vector, which describes spatial road shape and vehicle orientation relative to the road. This state vector is estimated every 40 ms by exploiting knowledge about the vehicle movement (spatio-temporal model of vehicle dynamics) and the road design rules (clothoidal segments). Kalman filter techniques are applied to obtain an optimal estimate of the state vector by evaluating the measurements of the road border positions in the image sequence taken by a set of CCD cameras. The road consists of segments with piecewise constant curvature parameters. The borders between these segments can be detected by applying methods which have been developed for detection of discontinuities during time-discrete measurements. The road recognition system has been tested in autonomous rides with VaMP on public Autobahnen in real traffic at speeds up to 130 km/h.

  4. Laboratory-acquired brucellosis

    DEFF Research Database (Denmark)

    Fabiansen, C.; Knudsen, J.D.; Lebech, A.M.

    2008-01-01

    Brucellosis is a rare disease in Denmark. We describe one case of laboratory-acquired brucellosis from an index patient to a laboratory technician following exposure to an infected blood culture in a clinical microbiology laboratory Udgivelsesdato: 2008/6/9......Brucellosis is a rare disease in Denmark. We describe one case of laboratory-acquired brucellosis from an index patient to a laboratory technician following exposure to an infected blood culture in a clinical microbiology laboratory Udgivelsesdato: 2008/6/9...

  5. Prognostic value of gradient echo T2* sequences for brain MR imaging in preterm infants

    Energy Technology Data Exchange (ETDEWEB)

    Bruine, Francisca T. de; Berg-Huysmans, Annette A. van den; Buchem, Mark A. van; Grond, Jeroen van der [Leiden University Medical Center, Department of Radiology, PO Box 9600, Leiden (Netherlands); Steggerda, Sylke J.; Leijser, Lara M.; Rijken, Monique [Leiden University Medical Center, Department of Pediatrics, subdivision of Neonatology, Leiden (Netherlands); Wezel-Meijler, Gerda van [Leiden University Medical Center, Department of Pediatrics, subdivision of Neonatology, Leiden (Netherlands); Isala Hospital, Department of Neonatology, Zwolle (Netherlands)

    2014-03-15

    Gradient echo T2*-W sequences are more sensitive than T2-W spin-echo sequences for detecting hemorrhages in the brain. The aim of this study is to correlate presence of hemosiderin deposits in the brain of very preterm infants (gestational age <32 weeks) detected by T2*-W gradient echo MRI to white matter injury and neurodevelopmental outcome at 2 years. In 101 preterm infants, presence and location of hemosiderin were assessed on T2*-W gradient echo MRI performed around term-equivalent age (range: 40-60 weeks). White matter injury was defined as the presence of >6 non-hemorrhagic punctate white matter lesions (PWML), cysts and/or ventricular dilatation. Six infants with post-hemorrhagic ventricular dilatation detected by US in the neonatal period were excluded. Infants were seen for follow-up at 2 years. Univariate and regression analysis assessed the relation between presence and location of hemosiderin, white matter injury and neurodevelopmental outcome. In 38/95 (40%) of the infants, hemosiderin was detected. Twenty percent (19/95) of the infants were lost to follow-up. There was a correlation between hemosiderin in the ventricular wall with >6 PWML (P < 0.001) and cysts (P < 0.001) at term-equivalent age, and with a lower psychomotor development index (PDI) (P=0.02) at 2 years. After correcting for known confounders (gestational age, gender, intrauterine growth retardation and white matter injury), the correlation with PDI was no longer significant. The clinical importance of detecting small hemosiderin deposits is limited as there is no independent association with neurodevelopmental outcome. (orig.)

  6. The 2012 Emilia seismic sequence (Northern Italy): Imaging the thrust fault system by accurate aftershock location

    Science.gov (United States)

    Govoni, Aladino; Marchetti, Alessandro; De Gori, Pasquale; Di Bona, Massimo; Lucente, Francesco Pio; Improta, Luigi; Chiarabba, Claudio; Nardi, Anna; Margheriti, Lucia; Agostinetti, Nicola Piana; Di Giovambattista, Rita; Latorre, Diana; Anselmi, Mario; Ciaccio, Maria Grazia; Moretti, Milena; Castellano, Corrado; Piccinini, Davide

    2014-05-01

    Starting from late May 2012, the Emilia region (Northern Italy) was severely shaken by an intense seismic sequence, originated from a ML 5.9 earthquake on May 20th, at a hypocentral depth of 6.3 km, with thrust-type focal mechanism. In the following days, the seismic rate remained high, counting 50 ML ≥ 2.0 earthquakes a day, on average. Seismicity spreads along a 30 km east-west elongated area, in the Po river alluvial plain, in the nearby of the cities Ferrara and Modena. Nine days after the first shock, another destructive thrust-type earthquake (ML 5.8) hit the area to the west, causing further damage and fatalities. Aftershocks following this second destructive event extended along the same east-westerly trend for further 20 km to the west, thus illuminating an area of about 50 km in length, on the whole. After the first shock struck, on May 20th, a dense network of temporary seismic stations, in addition to the permanent ones, was deployed in the meizoseismal area, leading to a sensible improvement of the earthquake monitoring capability there. A combined dataset, including three-component seismic waveforms recorded by both permanent and temporary stations, has been analyzed in order to obtain an appropriate 1-D velocity model for earthquake location in the study area. Here we describe the main seismological characteristics of this seismic sequence and, relying on refined earthquakes location, we make inferences on the geometry of the thrust system responsible for the two strongest shocks.

  7. An image encryption scheme based on the MLNCML system using DNA sequences

    Science.gov (United States)

    Zhang, Ying-Qian; Wang, Xing-Yuan; Liu, Jia; Chi, Ze-Lin

    2016-07-01

    We propose a new image scheme based on the spatiotemporal chaos of the Mixed Linear-Nonlinear Coupled Map Lattices (MLNCML). This spatiotemporal chaotic system has more cryptographic features in dynamics than the system of Coupled Map Lattices (CML). In the proposed scheme, we employ the strategy of DNA computing and one time pad encryption policy, which can enhance the sensitivity to the plaintext and resist differential attack, brute-force attack, statistical attack and plaintext attack. Simulation results and theoretical analysis indicate that the proposed scheme has superior high security.

  8. Enhanced learning of natural visual sequences in newborn chicks.

    Science.gov (United States)

    Wood, Justin N; Prasad, Aditya; Goldman, Jason G; Wood, Samantha M W

    2016-07-01

    To what extent are newborn brains designed to operate over natural visual input? To address this question, we used a high-throughput controlled-rearing method to examine whether newborn chicks (Gallus gallus) show enhanced learning of natural visual sequences at the onset of vision. We took the same set of images and grouped them into either natural sequences (i.e., sequences showing different viewpoints of the same real-world object) or unnatural sequences (i.e., sequences showing different images of different real-world objects). When raised in virtual worlds containing natural sequences, newborn chicks developed the ability to recognize familiar images of objects. Conversely, when raised in virtual worlds containing unnatural sequences, newborn chicks' object recognition abilities were severely impaired. In fact, the majority of the chicks raised with the unnatural sequences failed to recognize familiar images of objects despite acquiring over 100 h of visual experience with those images. Thus, newborn chicks show enhanced learning of natural visual sequences at the onset of vision. These results indicate that newborn brains are designed to operate over natural visual input.

  9. Gadobenate dimeglumine-enhanced MR of VX2 carcinoma in rabbit liver: usefulness of the delayed phase imaging and optimal pulse sequence

    International Nuclear Information System (INIS)

    Cho, Seung Il; Lee, Jeong Min; Kim, Young Kon; Kim, Chong Soo

    2002-01-01

    To assess the diagnostic value of delayed imaging using gadobenate dimeglumine (MultiHance) and to determine the optimal pulse sequence for the detection of VX2 carcinoma lesions in the rabbit. Twelve VX2 carcinomas implanted in the livers of eleven New Zealand rabbits were studied. All patients underwent an MR protocal consisting of precontrast T2-and T1-weighted sequences, followed by repetition of the T1-weighted sequence at 0 to 30 (arterial phase). 31-60 (portal phase), and 40 minutes (delayed phase) after the intravenous administration of 0.1 mmol/kg of gadobenate dimeglumine. The signal-to-noise ratio (SNR) of the liver and VX2 tumor, and the lesion-to-liver contrast-to-noise ratio (CNR) of precontrast and postcontrast MR images were quantitatively analyzed, and two experienced radiologists evaluated image quality in terms of lesion conspicuity, artifact, mass delineation, and vascular anatomy. Liver SNR was significantly higher at delayed imaging than at precontrast, arterial, and portal imaging (p<0.05), while lesion SNR was significantly higher at delayed imaging than at precontrast imaging (p<0.05). Lesion CNR was higher at delayed imaging than at precontrast and portal phase imaging (p<0.05), but there was no difference between arterial and delayed imaging. The latter provided better mass delineation than precontrast, arterial and portal phase imaging (p<0.05). While in terms of lesion conspicuity and vascular anatomy, the delayed phase was better than the arterial phase (p<0.05) but similar to the precontrast and portal phase. During the delayed phase, the gradient-echo sequence showed better results than the spin-echo in terms of liver SNR, and lesion SNR and CNR (p<0.05). Because it provides better lesion conspicuity and mass delineation by improving liver SNR and lesion-to-liver CNR, the addition of the delayed phase to a dynamic MRI sequence after gadobenate dimeglumine adminstration facilitates lesion detection. For delayed-phase imaging, the

  10. Gadobenate dimeglumine-enhanced MR of VX2 carcinoma in rabbit liver: usefulness of the delayed phase imaging and optimal pulse sequence

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Seung Il; Lee, Jeong Min; Kim, Young Kon; Kim, Chong Soo [College of Medicine, Chonbuk National Univ., Chonju (Korea, Republic of)

    2002-07-01

    To assess the diagnostic value of delayed imaging using gadobenate dimeglumine (MultiHance) and to determine the optimal pulse sequence for the detection of VX2 carcinoma lesions in the rabbit. Twelve VX2 carcinomas implanted in the livers of eleven New Zealand rabbits were studied. All patients underwent an MR protocal consisting of precontrast T2-and T1-weighted sequences, followed by repetition of the T1-weighted sequence at 0 to 30 (arterial phase). 31-60 (portal phase), and 40 minutes (delayed phase) after the intravenous administration of 0.1 mmol/kg of gadobenate dimeglumine. The signal-to-noise ratio (SNR) of the liver and VX2 tumor, and the lesion-to-liver contrast-to-noise ratio (CNR) of precontrast and postcontrast MR images were quantitatively analyzed, and two experienced radiologists evaluated image quality in terms of lesion conspicuity, artifact, mass delineation, and vascular anatomy. Liver SNR was significantly higher at delayed imaging than at precontrast, arterial, and portal imaging (p<0.05), while lesion SNR was significantly higher at delayed imaging than at precontrast imaging (p<0.05). Lesion CNR was higher at delayed imaging than at precontrast and portal phase imaging (p<0.05), but there was no difference between arterial and delayed imaging. The latter provided better mass delineation than precontrast, arterial and portal phase imaging (p<0.05). While in terms of lesion conspicuity and vascular anatomy, the delayed phase was better than the arterial phase (p<0.05) but similar to the precontrast and portal phase. During the delayed phase, the gradient-echo sequence showed better results than the spin-echo in terms of liver SNR, and lesion SNR and CNR (p<0.05). Because it provides better lesion conspicuity and mass delineation by improving liver SNR and lesion-to-liver CNR, the addition of the delayed phase to a dynamic MRI sequence after gadobenate dimeglumine adminstration facilitates lesion detection. For delayed-phase imaging, the

  11. A prospective gating method to acquire a diverse set of free-breathing CT images for model-based 4DCT

    Science.gov (United States)

    O'Connell, D.; Ruan, D.; Thomas, D. H.; Dou, T. H.; Lewis, J. H.; Santhanam, A.; Lee, P.; Low, D. A.

    2018-02-01

    Breathing motion modeling requires observation of tissues at sufficiently distinct respiratory states for proper 4D characterization. This work proposes a method to improve sampling of the breathing cycle with limited imaging dose. We designed and tested a prospective free-breathing acquisition protocol with a simulation using datasets from five patients imaged with a model-based 4DCT technique. Each dataset contained 25 free-breathing fast helical CT scans with simultaneous breathing surrogate measurements. Tissue displacements were measured using deformable image registration. A correspondence model related tissue displacement to the surrogate. Model residual was computed by comparing predicted displacements to image registration results. To determine a stopping criteria for the prospective protocol, i.e. when the breathing cycle had been sufficiently sampled, subsets of N scans where 5  ⩽  N  ⩽  9 were used to fit reduced models for each patient. A previously published metric was employed to describe the phase coverage, or ‘spread’, of the respiratory trajectories of each subset. Minimum phase coverage necessary to achieve mean model residual within 0.5 mm of the full 25-scan model was determined and used as the stopping criteria. Using the patient breathing traces, a prospective acquisition protocol was simulated. In all patients, phase coverage greater than the threshold necessary for model accuracy within 0.5 mm of the 25 scan model was achieved in six or fewer scans. The prospectively selected respiratory trajectories ranked in the (97.5  ±  4.2)th percentile among subsets of the originally sampled scans on average. Simulation results suggest that the proposed prospective method provides an effective means to sample the breathing cycle with limited free-breathing scans. One application of the method is to reduce the imaging dose of a previously published model-based 4DCT protocol to 25% of its original value while

  12. Repeatability of Brain Volume Measurements Made with the Atlas-based Method from T1-weighted Images Acquired Using a 0.4 Tesla Low Field MR Scanner.

    Science.gov (United States)

    Goto, Masami; Suzuki, Makoto; Mizukami, Shinya; Abe, Osamu; Aoki, Shigeki; Miyati, Tosiaki; Fukuda, Michinari; Gomi, Tsutomu; Takeda, Tohoru

    2016-10-11

    An understanding of the repeatability of measured results is important for both the atlas-based and voxel-based morphometry (VBM) methods of magnetic resonance (MR) brain volumetry. However, many recent studies that have investigated the repeatability of brain volume measurements have been performed using static magnetic fields of 1-4 tesla, and no study has used a low-strength static magnetic field. The aim of this study was to investigate the repeatability of measured volumes using the atlas-based method and a low-strength static magnetic field (0.4 tesla). Ten healthy volunteers participated in this study. Using a 0.4 tesla magnetic resonance imaging (MRI) scanner and a quadrature head coil, three-dimensional T 1 -weighted images (3D-T 1 WIs) were obtained from each subject, twice on the same day. VBM8 software was used to construct segmented normalized images [gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF) images]. The regions-of-interest (ROIs) of GM, WM, CSF, hippocampus (HC), orbital gyrus (OG), and cerebellum posterior lobe (CPL) were generated using WFU PickAtlas. The percentage change was defined as[100 × (measured volume with first segmented image - mean volume in each subject)/(mean volume in each subject)]The average percentage change was calculated as the percentage change in the 6 ROIs of the 10 subjects. The mean of the average percentage changes for each ROI was as follows: GM, 0.556%; WM, 0.324%; CSF, 0.573%; HC, 0.645%; OG, 1.74%; and CPL, 0.471%. The average percentage change was higher for the orbital gyrus than for the other ROIs. We consider that repeatability of the atlas-based method is similar between 0.4 and 1.5 tesla MR scanners. To our knowledge, this is the first report to show that the level of repeatability with a 0.4 tesla MR scanner is adequate for the estimation of brain volume change by the atlas-based method.

  13. Object analysis of bone marrow MR imaging using double echo STIR sequence in hematological diseases

    Energy Technology Data Exchange (ETDEWEB)

    Mizuno, Hitomi [Saitama Medical School, Moroyama (Japan)

    1995-07-01

    The bone marrow of 84 patients with hematological disorders was investigated using short inversion time inversion recovery sequence (STIR) on an 1.5 Tesla superconducting MRI system. Double echo times of 20 and 100 msec were applied to research the signal characteristics of the lesion and carry out quantitative analysis of the receiver operating characteristic curve (ROC). The hematological diseases included 19 cases of myelodysplastic syndrome (MDS), 18 of multiple myeloma (MM), 18 of chronic myelocytic leukemia (CML), 9 of aplastic anemia (AA), 8 of acute myelocytic leukemia (AML), 3 of chronic lymphocytic leukemia (CLL), 3 of myelofibrosis, and 3 others. Using STIR with double echo times, bone marrow showed high signal intensity (SI) on short TE and low SI on long TE in MDS and CML; high SI on short and long TE in myelofibrosis and CLL; high SI on short TE and high to moderately high SI on long TE in MM; and low SI on short and long TE in AA. Quantitative analysis of 33 patients showed high sensitivity and specificity in AA (81% and 94%, respectively) and moderate sensitivity and high specificity in MM (61%, 88%). CML and MDS were similar with low sensitivities (40%, 41%) and high specificities (80%, 78%). Differential diagnosis between CML and MDS was difficult using STIR with the double echo time method. (author).

  14. Role of targeted magnetic resonance imaging sequences in the surgical management of anterior skull base pathology.

    Science.gov (United States)

    Chawla, S; Bowman, J; Gandhi, M; Panizza, B

    2017-01-01

    The skull base is a highly complex anatomical region that provides passage for important nerves and vessels as they course into and out of the cranial cavity. Key to the management of pathology in this region is a thorough understanding of the anatomy, with its variations, and the relationship of various neurovascular structures to the pathology in question. Targeted high-resolution magnetic resonance imaging on high field strength magnets can enable the skull base surgeon to understand this intricate relationship and deal with the pathology from a position of relative advantage. With the help of case studies, this paper illustrates the application of specialised magnetic resonance techniques to study pathology of the orbital apex in particular. The fine anatomical detail provided gives surgeons the ability to design an endonasal endoscopic procedure appropriate to the anatomy of the pathology.

  15. Aeromonas salmonicida - Epidemiology, whole genome sequencing, detection and in vivo imaging

    DEFF Research Database (Denmark)

    Bartkova, Simona

    causes problems in sea reared rainbow trout (Oncorhynchus mykiss) production. Outbreaks occur repeatedly during stressful conditions such as elevated temperatures, in spite of commercial vaccines being applied. Besides seemingly lacking adequate protection, the vaccines also produce undesirable side...... of the concerns regarding A. salmonicida. First, we focused on investigation of the route of entry and initial dissemination of A. salmonicida in fish. This was done by tracing the bacterium using in vivo bioluminescence imaging. A Danish strain was transformed with a plasmid vector containing a green...... was subsequently turned to finding a sensitive method for detecting A. salmonicida in infected and possible carrier fish. For this, a previously developed quantitative real-time polymerase chain reaction (real-time PCR) targeting the aopP gene located on A. salmonicida plasmid pAsal1 was assessed. The real...

  16. Three-Dimensional Constructive Interference in Steady State Sequences and Phase-Contrast Magnetic Resonance Imaging of Arrested Hydrocephalus.

    Science.gov (United States)

    Elkafrawy, Fatma; Reda, Ihab; Elsirafy, Mohamed; Gawad, Mohamed Saied Abdel; Elnaggar, Alaa; Khalek Abdel Razek, Ahmed Abdel

    2017-02-01

    To evaluate the role of three-dimensional constructive interference in steady state (3D-CISS) sequences and phase-contrast magnetic resonance imaging (PC-MRI) in patients with arrested hydrocephalus. A prospective study of 20 patients with arrested hydrocephalus was carried out. All patients underwent PC-MRI and 3D-CISS for assessment of the aqueduct. Axial (through-plane), sagittal (in-plane) PC-MRI, and sagittal 3D-CISS were applied to assess the cerebral aqueduct and the spontaneous third ventriculostomy if present. Aqueductal patency was graded using 3D-CISS and PC-MRI. Quantitative analysis of flow through the aqueduct was performed using PC-MRI. The causes of obstruction were aqueductal obstruction in 75% (n = 15), third ventricular obstruction in 5% (n = 1), and fourth ventricular obstruction in 20% (n = 4). The cause of arrest of hydrocephalus was spontaneous third ventriculostomy in 65% (n = 13), endoscopic third ventriculostomy in 10% (n = 2), and ventriculoperitoneal shunt in 5% (n = 1), and no cause could be detected in 20% of patients (n = 4). There is a positive correlation (r = 0.80) and moderate agreement (κ = 0.509) of grading with PC-MRI and 3D-CISS sequences. The mean peak systolic velocity of cerebrospinal fluid was 1.86 ± 2.48 cm/second, the stroke volume was 6.43 ± 13.81 μL/cycle, and the mean flow was 0.21 ± 0.32 mL/minute. We concluded that 3D-CISS and PC-MRI are noninvasive sequences for diagnosis of the level and cause of arrested hydrocephalus. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. A review of techniques for the identification and measurement of fish in underwater stereo-video image sequences

    Science.gov (United States)

    Shortis, Mark R.; Ravanbakskh, Mehdi; Shaifat, Faisal; Harvey, Euan S.; Mian, Ajmal; Seager, James W.; Culverhouse, Philip F.; Cline, Danelle E.; Edgington, Duane R.

    2013-04-01

    Underwater stereo-video measurement systems are used widely for counting and measuring fish in aquaculture, fisheries and conservation management. To determine population counts, spatial or temporal frequencies, and age or weight distributions, snout to fork length measurements are captured from the video sequences, most commonly using a point and click process by a human operator. Current research aims to automate the measurement and counting task in order to improve the efficiency of the process and expand the use of stereo-video systems within marine science. A fully automated process will require the detection and identification of candidates for measurement, followed by the snout to fork length measurement, as well as the counting and tracking of fish. This paper presents a review of the techniques used for the detection, identification, measurement, counting and tracking of fish in underwater stereo-video image sequences, including consideration of the changing body shape. The review will analyse the most commonly used approaches, leading to an evaluation of the techniques most likely to be a general solution to the complete process of detection, identification, measurement, counting and tracking.

  18. Dynamic MR imaging of the temporomandibular joint arthrosis using spoiled GRASS sequence

    Energy Technology Data Exchange (ETDEWEB)

    Suenaga, Shigeaki; Hamamoto, Sadatoshi; Kawano, Kazunori (Kagoshima Univ. (Japan). Dental School) (and others)

    1994-07-01

    The purpose of this study was to quantitatively evaluate contrast enhancement effects of the posterior disk attachment in the temporomandibular joint arthrosis using dynamic MRI with bilateral surface coils. One hundred twenty-four temporomandibular joints in 96 symptomatic patients and 27 control subjects were examined with a spoiled GRASS pulse sequence (TR: 35 ms, TE: 8 ms, flip angle: 60deg). One sagittal scan was performed prior to injection, then 0.1 mmol/kg of Gd-DTPA was given as a rapid bolus injection, immediately after which scans were performed at 30 seconds intervals for a period of 5 minutes. Signal intensity (SI) was measured from the ROI of the posterior disk attachment region. The contrast enhancement effects may be calculated by SI ratio (SIR) = ( SI[sup post]-SI[sup pre])/SI[sup pre], where SI[sup post] and SI[sup pre] were the signal intensities after and before administration of contrast medium. The time intensity curve of SIR versus time after injection was obtained on each symptoms. Join pain group (85 joints) tended to show a rapid enhancement pattern, while control group (54 joints), joint sound or opening limitation group (39 joints), and asymptomatic group (68 joints) showed a relatively gradual enhancement pattern. The drop of SIR in four groups were hardly observed during examination. Mean peak SIR of control group, joint pain group, joint sound or opening limitation group, and asymptomatic group was 0.62[+-]0.24 (SD), 1.53[+-]0.69, 0.73[+-]0.38 and 0.78[+-]0.44 respectively. The mean SIR of pain group was significantly (P<0.001, t-test) higher than that of other groups. These results suggested that dynamic MRI of the temporomandibular joint may effectively depict the inflammatory changes of the posterior disk attachment. (author).

  19. Dynamic MR imaging of the temporomandibular joint arthrosis using spoiled GRASS sequence

    International Nuclear Information System (INIS)

    Suenaga, Shigeaki; Hamamoto, Sadatoshi; Kawano, Kazunori

    1994-01-01

    The purpose of this study was to quantitatively evaluate contrast enhancement effects of the posterior disk attachment in the temporomandibular joint arthrosis using dynamic MRI with bilateral surface coils. One hundred twenty-four temporomandibular joints in 96 symptomatic patients and 27 control subjects were examined with a spoiled GRASS pulse sequence (TR: 35 ms, TE: 8 ms, flip angle: 60deg). One sagittal scan was performed prior to injection, then 0.1 mmol/kg of Gd-DTPA was given as a rapid bolus injection, immediately after which scans were performed at 30 seconds intervals for a period of 5 minutes. Signal intensity (SI) was measured from the ROI of the posterior disk attachment region. The contrast enhancement effects may be calculated by SI ratio (SIR) = ( SI post -SI pre )/SI pre , where SI post and SI pre were the signal intensities after and before administration of contrast medium. The time intensity curve of SIR versus time after injection was obtained on each symptoms. Join pain group (85 joints) tended to show a rapid enhancement pattern, while control group (54 joints), joint sound or opening limitation group (39 joints), and asymptomatic group (68 joints) showed a relatively gradual enhancement pattern. The drop of SIR in four groups were hardly observed during examination. Mean peak SIR of control group, joint pain group, joint sound or opening limitation group, and asymptomatic group was 0.62±0.24 (SD), 1.53±0.69, 0.73±0.38 and 0.78±0.44 respectively. The mean SIR of pain group was significantly (P<0.001, t-test) higher than that of other groups. These results suggested that dynamic MRI of the temporomandibular joint may effectively depict the inflammatory changes of the posterior disk attachment. (author)

  20. Driven equilibrium (drive) MR imaging of the cranial nerves V-VIII: comparison with the T2-weighted 3D TSE sequence

    Energy Technology Data Exchange (ETDEWEB)

    Ciftci, E. E-mail: eciftcis7@hotmail.com; Anik, Yonca; Arslan, Arzu; Akansel, Gur; Sarisoy, Tahsin; Demirci, Ali

    2004-09-01

    Purpose: The aim of this study is to evaluate the efficacy of the driven equilibrium radio frequency reset pulse (DRIVE) on image quality and nerve detection when used in adjunction with T2-weighted 3D turbo spin-echo (TSE) sequence. Materials and methods: Forty-five patients with cranial nerve symptoms referable to the cerebellopontine angle (CPA) were examined using a T2-weighted 3D TSE pulse sequence with and without DRIVE. MR imaging was performed on a 1.5-T MRI scanner. In addition to the axial resource images, reformatted oblique sagittal, oblique coronal and maximum intensity projection (MIP) images of the inner ear were evaluated. The nerve identification and image quality were graded for the cranial nerves V-VIII as well as inner ear structures. These structures were chosen because fluid-solid interfaces existed due to the CSF around (the cranial nerves V-VIII) or the endolymph within (the inner ear structures). Statistical analysis was performed using the Wilcoxon test. P<0.05 was considered significant. Results: The addition of the DRIVE pulse shortens the scan time by 25%. T2-weighted 3D TSE sequence with DRIVE performed slightly better than the T2-weighted 3D TSE sequence without DRIVE in identifying the individual nerves. The image quality was also slightly better with DRIVE. Conclusion: The addition of the DRIVE pulse to the T2-weighted 3D TSE sequence is preferable when imaging the cranial nerves surrounded by the CSF, or fluid-filled structures because of shorter scan time and better image quality due to reduced flow artifacts.

  1. Driven equilibrium (drive) MR imaging of the cranial nerves V-VIII: comparison with the T2-weighted 3D TSE sequence

    International Nuclear Information System (INIS)

    Ciftci, E.; Anik, Yonca; Arslan, Arzu; Akansel, Gur; Sarisoy, Tahsin; Demirci, Ali

    2004-01-01

    Purpose: The aim of this study is to evaluate the efficacy of the driven equilibrium radio frequency reset pulse (DRIVE) on image quality and nerve detection when used in adjunction with T2-weighted 3D turbo spin-echo (TSE) sequence. Materials and methods: Forty-five patients with cranial nerve symptoms referable to the cerebellopontine angle (CPA) were examined using a T2-weighted 3D TSE pulse sequence with and without DRIVE. MR imaging was performed on a 1.5-T MRI scanner. In addition to the axial resource images, reformatted oblique sagittal, oblique coronal and maximum intensity projection (MIP) images of the inner ear were evaluated. The nerve identification and image quality were graded for the cranial nerves V-VIII as well as inner ear structures. These structures were chosen because fluid-solid interfaces existed due to the CSF around (the cranial nerves V-VIII) or the endolymph within (the inner ear structures). Statistical analysis was performed using the Wilcoxon test. P<0.05 was considered significant. Results: The addition of the DRIVE pulse shortens the scan time by 25%. T2-weighted 3D TSE sequence with DRIVE performed slightly better than the T2-weighted 3D TSE sequence without DRIVE in identifying the individual nerves. The image quality was also slightly better with DRIVE. Conclusion: The addition of the DRIVE pulse to the T2-weighted 3D TSE sequence is preferable when imaging the cranial nerves surrounded by the CSF, or fluid-filled structures because of shorter scan time and better image quality due to reduced flow artifacts

  2. Imaging different components of a tectonic tremor sequence in southwestern Japan using an automatic statistical detection and location method

    Science.gov (United States)

    Poiata, Natalia; Vilotte, Jean-Pierre; Bernard, Pascal; Satriano, Claudio; Obara, Kazushige

    2018-06-01

    the long-duration energy-release regions, matching the large-scale clustering features evidenced from the low-frequency earthquake's activity analysis. Further examination of the two catalogues showed that the extracted short-duration low-frequency earthquakes activity coincides in space, within about 10-15 km distance, with the longer-duration energy sources during the tectonic tremor sequence. This observation provides a potential constraint on the size of the longer-duration energy-radiating source region in relation with the clustering of low-frequency earthquakes activity during the analysed tectonic tremor sequence. We show that advanced statistical network-based methods offer new capabilities for automatic high-resolution detection, location and monitoring of different scale-components of tectonic tremor activity, enriching existing slow earthquakes catalogues. Systematic application of such methods to large continuous data sets will allow imaging the slow transient seismic energy-release activity at higher resolution, and therefore, provide new insights into the underlying multiscale mechanisms of slow earthquakes generation.

  3. Imaging different components of a tectonic tremor sequence in southwestern Japan using an automatic statistical detection and location method

    Science.gov (United States)

    Poiata, Natalia; Vilotte, Jean-Pierre; Bernard, Pascal; Satriano, Claudio; Obara, Kazushige

    2018-02-01

    the long-duration energy-release regions, matching the large-scale clustering features evidenced from the low-frequency earthquake's activity analysis. Further examination of the two catalogues showed that the extracted short-duration low-frequency earthquakes activity coincides in space, within about 10-15 km distance, with the longer-duration energy sources during the tectonic tremor sequence. This observation provides a potential constraint on the size of the longer-duration energy-radiating source region in relation with the clustering of low-frequency earthquakes activity during the analysed tectonic tremor sequence. We show that advanced statistical network-based methods offer new capabilities for automatic high-resolution detection, location and monitoring of different scale-components of tectonic tremor activity, enriching existing slow earthquakes catalogues. Systematic application of such methods to large continuous data sets will allow imaging the slow transient seismic energy-release activity at higher resolution, and therefore, provide new insights into the underlying multi-scale mechanisms of slow earthquakes generation.

  4. In vivo tumor targeting and imaging with engineered trivalent antibody fragments containing collagen-derived sequences.

    Directory of Open Access Journals (Sweden)

    Angel M Cuesta

    Full Text Available There is an urgent need to develop new and effective agents for cancer targeting. In this work, a multivalent antibody is characterized in vivo in living animals. The antibody, termed "trimerbody", comprises a single-chain antibody (scFv fragment connected to the N-terminal trimerization subdomain of collagen XVIII NC1 by a flexible linker. As indicated by computer graphic modeling, the trimerbody has a tripod-shaped structure with three highly flexible scFv heads radially outward oriented. Trimerbodies are trimeric in solution and exhibited multivalent binding, which provides them with at least a 100-fold increase in functional affinity than the monovalent scFv. Our results also demonstrate the feasibility of producing functional bispecific trimerbodies, which concurrently bind two different ligands. A trimerbody specific for the carcinoembryonic antigen (CEA, a classic tumor-associated antigen, showed efficient tumor targeting after systemic administration in mice bearing CEA-positive tumors. Importantly, a trimerbody that recognizes an angiogenesis-associated laminin epitope, showed excellent tumor localization in several cancer types, including fibrosarcomas and carcinomas. These results illustrate the potential of this new antibody format for imaging and therapeutic applications, and suggest that some laminin epitopes might be universal targets for cancer targeting.

  5. Natural image sequences constrain dynamic receptive fields and imply a sparse code.

    Science.gov (United States)

    Häusler, Chris; Susemihl, Alex; Nawrot, Martin P

    2013-11-06

    In their natural environment, animals experience a complex and dynamic visual scenery. Under such natural stimulus conditions, neurons in the visual cortex employ a spatially and temporally sparse code. For the input scenario of natural still images, previous work demonstrated that unsupervised feature learning combined with the constraint of sparse coding can predict physiologically measured receptive fields of simple cells in the primary visual cortex. This convincingly indicated that the mammalian visual system is adapted to the natural spatial input statistics. Here, we extend this approach to the time domain in order to predict dynamic receptive fields that can account for both spatial and temporal sparse activation in biological neurons. We rely on temporal restricted Boltzmann machines and suggest a novel temporal autoencoding training procedure. When tested on a dynamic multi-variate benchmark dataset this method outperformed existing models of this class. Learning features on a large dataset of natural movies allowed us to model spatio-temporal receptive fields for single neurons. They resemble temporally smooth transformations of previously obtained static receptive fields and are thus consistent with existing theories. A neuronal spike response model demonstrates how the dynamic receptive field facilitates temporal and population sparseness. We discuss the potential mechanisms and benefits of a spatially and temporally sparse representation of natural visual input. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

  6. Automatically Identifying Fusion Events between GLUT4 Storage Vesicles and the Plasma Membrane in TIRF Microscopy Image Sequences

    Directory of Open Access Journals (Sweden)

    Jian Wu

    2015-01-01

    Full Text Available Quantitative analysis of the dynamic behavior about membrane-bound secretory vesicles has proven to be important in biological research. This paper proposes a novel approach to automatically identify the elusive fusion events between VAMP2-pHluorin labeled GLUT4 storage vesicles (GSVs and the plasma membrane. The differentiation is implemented to detect the initiation of fusion events by modified forward subtraction of consecutive frames in the TIRFM image sequence. Spatially connected pixels in difference images brighter than a specified adaptive threshold are grouped into a distinct fusion spot. The vesicles are located at the intensity-weighted centroid of their fusion spots. To reveal the true in vivo nature of a fusion event, 2D Gaussian fitting for the fusion spot is used to derive the intensity-weighted centroid and the spot size during the fusion process. The fusion event and its termination can be determined according to the change of spot size. The method is evaluated on real experiment data with ground truth annotated by expert cell biologists. The evaluation results show that it can achieve relatively high accuracy comparing favorably to the manual analysis, yet at a small fraction of time.

  7. Pulmonary parenchyma segmentation in thin CT image sequences with spectral clustering and geodesic active contour model based on similarity

    Science.gov (United States)

    He, Nana; Zhang, Xiaolong; Zhao, Juanjuan; Zhao, Huilan; Qiang, Yan

    2017-07-01

    While the popular thin layer scanning technology of spiral CT has helped to improve diagnoses of lung diseases, the large volumes of scanning images produced by the technology also dramatically increase the load of physicians in lesion detection. Computer-aided diagnosis techniques like lesions segmentation in thin CT sequences have been developed to address this issue, but it remains a challenge to achieve high segmentation efficiency and accuracy without much involvement of human manual intervention. In this paper, we present our research on automated segmentation of lung parenchyma with an improved geodesic active contour model that is geodesic active contour model based on similarity (GACBS). Combining spectral clustering algorithm based on Nystrom (SCN) with GACBS, this algorithm first extracts key image slices, then uses these slices to generate an initial contour of pulmonary parenchyma of un-segmented slices with an interpolation algorithm, and finally segments lung parenchyma of un-segmented slices. Experimental results show that the segmentation results generated by our method are close to what manual segmentation can produce, with an average volume overlap ratio of 91.48%.

  8. MR Imaging of the Internal Auditory Canal and Inner Ear at 3T: Comparison between 3D Driven Equilibrium and 3D Balanced Fast Field Echo Sequences

    Energy Technology Data Exchange (ETDEWEB)

    Byun, Jun Soo; Kim, Hyung Jin; Yim, Yoo Jeong; Kim, Sung Tae; Jeon, Pyoung; Kim, Keon Ha [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Kim, Sam Soo; Jeon, Yong Hwan; Lee, Ji Won [Kangwon National University College of Medicine, Chuncheon (Korea, Republic of)

    2008-06-15

    To compare the use of 3D driven equilibrium (DRIVE) imaging with 3D balanced fast field echo (bFFE) imaging in the assessment of the anatomic structures of the internal auditory canal (IAC) and inner ear at 3 Tesla (T). Thirty ears of 15 subjects (7 men and 8 women; age range, 22 71 years; average age, 50 years) without evidence of ear problems were examined on a whole-body 3T MR scanner with both 3D DRIVE and 3D bFFE sequences by using an 8-channel sensitivity encoding (SENSE) head coil. Two neuroradiologists reviewed both MR images with particular attention to the visibility of the anatomic structures, including four branches of the cranial nerves within the IAC, anatomic structures of the cochlea, vestibule, and three semicircular canals. Although both techniques provided images of relatively good quality, the 3D DRIVE sequence was somewhat superior to the 3D bFFE sequence. The discrepancies were more prominent for the basal turn of the cochlea, vestibule, and all semicircular canals, and were thought to be attributed to the presence of greater magnetic susceptibility artifacts inherent to gradient-echo techniques such as bFFE. Because of higher image quality and less susceptibility artifacts, we highly recommend the employment of 3D DRIVE imaging as the MR imaging choice for the IAC and inner ear

  9. Contrast-enhanced Magnetic Resonance Imaging of Pelvic Bone Metastases at 3.0 T: Comparison Between 3-dimensional T1-weighted CAIPIRINHA-VIBE Sequence and 2-dimensional T1-weighted Turbo Spin-Echo Sequence.

    Science.gov (United States)

    Yoon, Min A; Hong, Suk-Joo; Lee, Kyu-Chong; Lee, Chang Hee

    2018-06-12

    This study aimed to compare 3-dimensional T1-weighted gradient-echo sequence (CAIPIRINHA-volumetric interpolated breath-hold examination [VIBE]) with 2-dimensional T1-weighted turbo spin-echo sequence for contrast-enhanced magnetic resonance imaging (MRI) of pelvic bone metastases at 3.0 T. Thirty-one contrast-enhanced MRIs of pelvic bone metastases were included. Two contrast-enhanced sequences were evaluated for the following parameters: overall image quality, sharpness of pelvic bone, iliac vessel clarity, artifact severity, and conspicuity and edge sharpness of the smallest metastases. Quantitative analysis was performed by calculating signal-to-noise ratio and contrast-to-noise ratio of the smallest metastases. Significant differences between the 2 sequences were assessed. CAIPIRINHA-VIBE had higher scores for overall image quality, pelvic bone sharpness, iliac vessel clarity, and edge sharpness of the metastatic lesions, and had less artifacts (all P 0.05). Our results suggest that CAIPIRINHA-VIBE may be superior to turbo spin-echo for contrast-enhanced MRI of pelvic bone metastases at 3.0 T.

  10. Low-field MR imaging of the spine. A comparative study of a traditional and a new, completely balanced gradient-echo sequence

    International Nuclear Information System (INIS)

    Drejer, J.; Thomsen, H.S.; Tanttu, J.

    1995-01-01

    49 patients underwent 53 examinations with both a traditional T1-weighted gradient-echo (PS) sequence and a new completely balanced steady-state 3-D (CBASS3D) sequence; 20 examinations included the cervical spine, 8 the thoracic spine and 25 the lumbar spine. All 106 examinations were reviewed twice regarding visibility of selected structures in the spinal region and diagnostic usefulness. The CBASS3D sequence delineated the medulla, nerve roots, CSF, the intervertebral discs and the posterior longitudinal ligament significantly better than the PS sequence. Disc hernia was also better visualised (p<0.01). There were significantly more artefacts on images obtained with the CBASS3D sequence, but they were usually outside the region of interest and occurred less frequently over time due to increased experience of the staff. Both reviewers found the diagnostic usefulness of CBASS3D to be superior compared to that of PS and excellent for diagnostic purposes. (orig./MG)

  11. Low-field MR imaging of the spine. A comparative study of a traditional and a new, completely balanced gradient-echo sequence

    Energy Technology Data Exchange (ETDEWEB)

    Drejer, J. [Dept. of Diagnostic Radiology, Herlev Hospital, Univ. Copenhagen (Denmark); Thomsen, H.S. [Dept. of Diagnostic Radiology, Herlev Hospital, Univ. Copenhagen (Denmark); Tanttu, J. [Picker Nordstar, Helsinki (Finland)

    1995-09-01

    49 patients underwent 53 examinations with both a traditional T1-weighted gradient-echo (PS) sequence and a new completely balanced steady-state 3-D (CBASS3D) sequence; 20 examinations included the cervical spine, 8 the thoracic spine and 25 the lumbar spine. All 106 examinations were reviewed twice regarding visibility of selected structures in the spinal region and diagnostic usefulness. The CBASS3D sequence delineated the medulla, nerve roots, CSF, the intervertebral discs and the posterior longitudinal ligament significantly better than the PS sequence. Disc hernia was also better visualised (p<0.01). There were significantly more artefacts on images obtained with the CBASS3D sequence, but they were usually outside the region of interest and occurred less frequently over time due to increased experience of the staff. Both reviewers found the diagnostic usefulness of CBASS3D to be superior compared to that of PS and excellent for diagnostic purposes. (orig./MG).

  12. Study of temporal sequences of LANSAT images to detect the accumulation of stress prior of strong earthquakes in Chile.

    Science.gov (United States)

    Arellano-Baeza, A. A.

    2016-12-01

    We studied the temporal evolution of the lineaments obtained from the LANSAT-8 associated to the accumulation of stress patterns related to the seismic activity. A lineament is generally defined as a straight or a somewhat curved feature in the landscape visible in a satellite image as an aligned sequence of pixels of a contrasting intensity compared to the background. The system of lineaments extracted from the satellite images is not identical to the geological lineaments; nevertheless, it generally reflects the structure of the faults and fractures in the Earth's crust. The satellite images were processed by the ADALGEO software developed by us. We selected two areas of study with different characteristics. The first area is located near to the Diego de Almagro town in the Copiapo region, Chile. This area did not show any strong seismic activity between 2010 and 2015. However, two strong earthquakes took place later on April 16, 2016 (Mw=5.3) and July 25, 2016 (Mw=6.1). The second area located near the Illapel town in Coquimbo region shows lack of strong earthquakes between 2010 and 2012 and strong seismic activity between 2012 and 2015, culminating by the September 16, 2015 earthquake (Mw=8.3). The distance between two areas is nearly 600 km. In case of the Diego de Almagro area, very few lineaments have been observed between 2010 and 2015, showing a significant increase during the 2016. In case of the Illapel region, the number of lineaments was always much higher, showing an explosive increase at the end of 2015. For both areas the lineaments changed its orientation before strong earthquakes.

  13. Examination of self-navigating MR-sequences for perfusion imaging of the kidneys; Untersuchung von selbstnavigierenden MR-Sequenzen fuer die Perfusionsbildgebung der Nieren

    Energy Technology Data Exchange (ETDEWEB)

    Lietzmann, Florian; Zoellner, Frank G.; Schad, Lothar R. [Heidelberg Univ. Medizinische Fakultaet Mannheim (Germany). Computerunterstuetzte Klinische Medizin; Michaely, Henrik J. [Heidelberg Univ. Medizinische Fakultaet Mannheim (Germany). Inst. fuer Klinische Radiologie und Nuklearmedizin

    2010-07-01

    Due to the worldwide increasing number of cases of chronic kidney diseases renal imaging - as a non-invasive technique in magnetic resonance imaging - has become a very important tool for an early diagnosis of probable insufficiencies and malfunction. Especially, dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) provides a technique to derive physiological parameters like renal blood flow or glomerular filtration rate. Similar to the entire field of abdominal imaging, the major problems are motion artifacts that primarily arise from the patient's respiration. The self-navigating BLADE-sequence with a post processing motion correction is an approach that does not require breath holding and is therefore also easily applicable to patients who are not able to undergo multiple breath hold examinations. In this work, a T1-weighted BLADE-sequence was optimized to demonstrate the feasibility of this technique to perfusion imaging. The number of phase-encoding lines of one BLADE has a direct impact on the reduction of motion artifacts. In comparison to standard DCE-MRI sequences, the developed BLADE-sequence with optimized number of phase encoding lines could significantly reduce motion artifacts. A quantitative analysis revealed that up to a 50% displacement of the kidneys could be corrected. Therefore, it was demonstrated that dynamic motion corrected measurements without the need of a breath hold-technique are feasible. (orig.)

  14. Dynamic MR cardiac perfusion studies in patients with acquired heart diseases

    International Nuclear Information System (INIS)

    Finelli, D.A.; Adler, L.P.; Paschal, C.B.; Haacke, E.M.

    1990-01-01

    The combination of ultrafast scanning techniques with contrast administration has opened new venues for MR imaging relating to the physiology of organ perfusion. Regional cardiac perfusion determinations lend important additional information to the morphologic and functional data provided by conventional cardiac MR imaging. The authors of this paper studied 10 patients with acquired heart diseases, including ischemic heart disease, cardiomyopathy, ventricular hypertrophy, and cardiac tumor, using conventional spin-echo imaging, cine gradient-echo imaging, and dynamic Gd-DTPA--enhanced perfusion imaging with an ultrafast, inversion-recovery, Turbo-fast low-angle shot sequence. This technique enables analysis of the first pass and early biodistribution phases following contrast administration, information that has been correlated with cardiac catheterization, single photo emission CT (SPECT), and administration emission tomographic (PET) data

  15. Combined Spectral and Spatial Modeling of Corn Yield Based on Aerial Images and Crop Surface Models Acquired with an Unmanned Aircraft System

    Directory of Open Access Journals (Sweden)

    Jakob Geipel

    2014-10-01

    Full Text Available Precision Farming (PF management strategies are commonly based on estimations of within-field yield potential, often derived from remotely-sensed products, e.g., Vegetation Index (VI maps. These well-established means, however, lack important information, like crop height. Combinations of VI-maps and detailed 3D Crop Surface Models (CSMs enable advanced methods for crop yield prediction. This work utilizes an Unmanned Aircraft System (UAS to capture standard RGB imagery datasets for corn grain yield prediction at three early- to mid-season growth stages. The imagery is processed into simple VI-orthoimages for crop/non-crop classification and 3D CSMs for crop height determination at different spatial resolutions. Three linear regression models are tested on their prediction ability using site-specific (i unclassified mean heights, (ii crop-classified mean heights and (iii a combination of crop-classified mean heights with according crop coverages. The models show determination coefficients \\({R}^{2}\\ of up to 0.74, whereas model (iii performs best with imagery captured at the end of stem elongation and intermediate spatial resolution (0.04m\\(\\cdot\\px\\(^{-1}\\.Following these results, combined spectral and spatial modeling, based on aerial images and CSMs, proves to be a suitable method for mid-season corn yield prediction.

  16. A practical and precise approach to quantification of body composition in cancer patients using computed tomography images acquired during routine care.

    Science.gov (United States)

    Mourtzakis, Marina; Prado, Carla M M; Lieffers, Jessica R; Reiman, Tony; McCargar, Linda J; Baracos, Vickie E

    2008-10-01

    Human body composition is important in numerous cancer research domains. Our objective was to evaluate clinically accessible methods to achieve practical and precise measures of body composition in cancer patients. Dual-energy X-ray absorptiometry (DXA)-based analysis of fat and fat-free mass was performed in 50 cancer patients and compared with bioelectrical impedance analysis (BIA) and with regional computed tomography (CT) images available in the patients' medical records. BIA overestimated or underestimated fat-free mass substantially compared with DXA as the method of reference (up to 9.3 kg difference). Significant changes in fat-free mass over time detected with DXA in a subset of 21 patients (+2.2 +/- 3.2%/100 days, p = 0.003), was beyond the limits of detection of BIA. Regional analysis of fat and fat-free tissue at the 3rd lumbar vertebra with either DXA or CT strongly predicted whole-body fat and fat-free mass (r = 0.86-0.94; p body composition.

  17. Spatial Co-Registration of Ultra-High Resolution Visible, Multispectral and Thermal Images Acquired with a Micro-UAV over Antarctic Moss Beds

    Directory of Open Access Journals (Sweden)

    Darren Turner

    2014-05-01

    Full Text Available In recent times, the use of Unmanned Aerial Vehicles (UAVs as tools for environmental remote sensing has become more commonplace. Compared to traditional airborne remote sensing, UAVs can provide finer spatial resolution data (up to 1 cm/pixel and higher temporal resolution data. For the purposes of vegetation monitoring, the use of multiple sensors such as near infrared and thermal infrared cameras are of benefit. Collecting data with multiple sensors, however, requires an accurate spatial co-registration of the various UAV image datasets. In this study, we used an Oktokopter UAV to investigate the physiological state of Antarctic moss ecosystems using three sensors: (i a visible camera (1 cm/pixel, (ii a 6 band multispectral camera (3 cm/pixel, and (iii a thermal infrared camera (10 cm/pixel. Imagery from each sensor was geo-referenced and mosaicked with a combination of commercially available software and our own algorithms based on the Scale Invariant Feature Transform (SIFT. The validation of the mosaic’s spatial co-registration revealed a mean root mean squared error (RMSE of 1.78 pixels. A thematic map of moss health, derived from the multispectral mosaic using a Modified Triangular Vegetation Index (MTVI2, and an indicative map of moss surface temperature were then combined to demonstrate sufficient accuracy of our co-registration methodology for UAV-based monitoring of Antarctic moss beds.

  18. Subjective and objective image qualities: a comparison of sagittal T2 weighted spin-echo and turbo-spin-eco sequences in magnetic resonance imaging of the spine by use of a subjective ranking system

    Energy Technology Data Exchange (ETDEWEB)

    Goerres, G. [Institut fuer diagnostische Radiologie, Departement Radiologie, Universitaetskliniken, Kantonsspital Basel (Switzerland); Mader, I. [Radiologische Gemeinschaftspraxis Dres. Siems, Grossmann, Bayreuth (Germany); Proske, M. [Klinikum Rosenheim (Germany). Inst. fuer Diagnostische Radiologie

    1998-12-31

    We evaluated the subjective image impression of two different magnetic resonance (MR) sequences by using a subjective ranking system. This ranking system was based on 20 criteria describing several tissue characteristics such as the signal intensity of normal anatomical structures and the changes of signal intensities and shape of lesions as well as artefacts. MR of the vertebral spine was performed in 48 female and 52 male patients (mean age 44.8 years) referred consecutively for investigation of a back problem. Ninety-six pathologies were found in 82 patients. Sagittal and axial T1 weighted spin-echo before and after administration of Gadolinium (Gd-DOTA), and sagittal T2 weighted spin-echo (T2wSE) and Turbo-spin-echo (TSE) sequences were performed by means of surface coils. Using the subjective ranking system the sagittal T2wSE and sagittal TSE were compared. Both sequences were suitable for identification of normal anatomy and pathologic changes and there was no trend for increased detection of disease by one imaging sequence over the other. We found that sagittal TSE sequences can replace sagittal T2wSE sequences in spinal MR and that artefacts at the cervical and lumbar spine are less frequent using TSE, thus confirming previous studies. In this study, our ranking system reveiled, that there are differences between the subjective judgement of image qualities and objective measurement of SNR. However, this approach may not be helpful to compare two different MR sequences as it is limited to the anatomical area investigated and is time consuming. The subjective image impression, i.e. the quality of images, may not always be represented by physical parameters such as a signal-to-noise ratio (SNR), radiologists should try to define influences of image quality also by subjective parameters. (orig.)

  19. MR imaging of cranial nerve lesions using six different high-resolution T1- and T2(*)-weighted 3D and 2D sequences

    Energy Technology Data Exchange (ETDEWEB)

    Seitz, J.; Held, P.; Strotzer, M.; Voelk, M.; Nitz, W.R.; Dorenbeck, U.; Feuerbach, S. [Univ. Hospital of Regensburg (Germany). Dept. of Diagnostic Radiology; Stamato, S. [Univ. of California, San Diego, CA (United States). Dept. of Radiology

    2002-07-01

    Purpose: To find a suitable high-resolution MR protocol for the visualization of lesions of all 12 cranial nerves. Material and Methods: Thirty-eight pathologically changed cranial nerves (17 patients) were studied with MR imaging at 1.5T using 3D T2*-weighted CISS, T1-weighted 3D MP-RAGE (without and with i.v. contrast medium), T2-weighted 3D TSE, T2-weighted 2D TSE and T1-weighted fat saturation 2D TSE sequences. Visibility of the 38 lesions of the 12 cranial nerves in each sequence was evaluated by consensus of two radiologists using an evaluation scale from 1 (excellently visible) to 4 (not visible). Results: The 3D CISS sequence provided the best resolution of the cranial nerves and their lesions when surrounded by CSF. In nerves which were not surrounded by CSF, the 2D T1-weighted contrast-enhanced fat suppression technique was the best sequence. Conclusions: A combination of 3D CISS, the 2D T1-weighted fat suppressed sequence and a 3D contrast-enhanced MP-RAGE proved to be the most useful sequence to visualize all lesions of the cranial nerves. For the determination of enhancement, an additional 3D MP-RAGE sequence without contrast medium is required. This sequence is also very sensitive for the detection of hemorrhage.

  20. MR imaging of cranial nerve lesions using six different high-resolution T1- and T2(*)-weighted 3D and 2D sequences

    International Nuclear Information System (INIS)

    Seitz, J.; Held, P.; Strotzer, M.; Voelk, M.; Nitz, W.R.; Dorenbeck, U.; Feuerbach, S.; Stamato, S.

    2002-01-01

    Purpose: To find a suitable high-resolution MR protocol for the visualization of lesions of all 12 cranial nerves. Material and Methods: Thirty-eight pathologically changed cranial nerves (17 patients) were studied with MR imaging at 1.5T using 3D T2*-weighted CISS, T1-weighted 3D MP-RAGE (without and with i.v. contrast medium), T2-weighted 3D TSE, T2-weighted 2D TSE and T1-weighted fat saturation 2D TSE sequences. Visibility of the 38 lesions of the 12 cranial nerves in each sequence was evaluated by consensus of two radiologists using an evaluation scale from 1 (excellently visible) to 4 (not visible). Results: The 3D CISS sequence provided the best resolution of the cranial nerves and their lesions when surrounded by CSF. In nerves which were not surrounded by CSF, the 2D T1-weighted contrast-enhanced fat suppression technique was the best sequence. Conclusions: A combination of 3D CISS, the 2D T1-weighted fat suppressed sequence and a 3D contrast-enhanced MP-RAGE proved to be the most useful sequence to visualize all lesions of the cranial nerves. For the determination of enhancement, an additional 3D MP-RAGE sequence without contrast medium is required. This sequence is also very sensitive for the detection of hemorrhage

  1. Community-acquired pneumonia.

    Science.gov (United States)

    Falguera, M; Ramírez, M F

    2015-11-01

    This article not only reviews the essential aspects of community-acquired pneumonia for daily clinical practice, but also highlights the controversial issues and provides the newest available information. Community-acquired pneumonia is considered in a broad sense, without excluding certain variants that, in recent years, a number of authors have managed to delineate, such as healthcare-associated pneumonia. The latter form is nothing more than the same disease that affects more frail patients, with a greater number of risk factors, both sharing an overall common approach. Copyright © 2015 Elsevier España, S.L.U. y Sociedad Española de Medicina Interna (SEMI). All rights reserved.

  2. Acquired hypofibrinogenemia: current perspectives

    Directory of Open Access Journals (Sweden)

    Besser MW

    2016-09-01

    Full Text Available Martin W Besser,1 Stephen G MacDonald2 1Department of Haematology, 2Department of Specialist Haemostasis, The Pathology Partnership, Addenbrooke’s Hospital, Cambridge, UK Abstract: Acquired hypofibrinogenemia is most frequently caused by hemodilution and consumption of clotting factors. The aggressive replacement of fibrinogen has become one of the core principles of modern management of massive hemorrhage. The best method for determining the patient’s fibrinogen level remains controversial, and particularly in acquired dysfibrinogenemia, could have major therapeutic implications depending on which quantification method is chosen. This review introduces the available laboratory and point-of-care methods and discusses the relative advantages and limitations. It also discusses current strategies for the correction of hypofibrinogenemia. Keywords: Clauss fibrinogen assay, fibrinogen antigen, viscoelastic testing, ­gravimetric fibrinogen assay, PT-derived fibrinogen, functional fibrinogen, direct oral anticoagulant, dysfibrinogenemia, afibrinogenemia

  3. Quantification of liver iron concentration with magnetic resonance imaging by combining T1-, T2-weighted spin echo sequences and a gradient echo sequence

    NARCIS (Netherlands)

    Kreeftenberg, HG; Mooyaart, EL; Sluiter, WJ; Kreeftenberg, HG; Huizenga, Reint

    Background: The aim of the study was to quantify hepatic iron by MRI for practical use. Methods: In twenty-three patients with various degrees of iron overload, measurements were carried out with a 1.5 Tesla MR unit. A combination of pulse sequences (T1, T2 and gradient echo) enabled us to quantify

  4. Can a single-shot black-blood T2-weighted spin-echo echo-planar imaging sequence with sensitivity encoding replace the respiratory-triggered turbo spin-echo sequence for the liver? An optimization and feasibility study.

    Science.gov (United States)

    Hussain, Shahid M; De Becker, Jan; Hop, Wim C J; Dwarkasing, Soendersing; Wielopolski, Piotr A

    2005-03-01

    To optimize and assess the feasibility of a single-shot black-blood T2-weighted spin-echo echo-planar imaging (SSBB-EPI) sequence for MRI of the liver using sensitivity encoding (SENSE), and compare the results with those obtained with a T2-weighted turbo spin-echo (TSE) sequence. Six volunteers and 16 patients were scanned at 1.5T (Philips Intera). In the volunteer study, we optimized the SSBB-EPI sequence by interactively changing the parameters (i.e., the resolution, echo time (TE), diffusion weighting with low b-values, and polarity of the phase-encoding gradient) with regard to distortion, suppression of the blood signal, and sensitivity to motion. The influence of each change was assessed. The optimized SSBB-EPI sequence was applied in patients (N = 16). A number of items, including the overall image quality (on a scale of 1-5), were used for graded evaluation. In addition, the signal-to-noise ratio (SNR) of the liver was calculated. Statistical analysis was carried out with the use of Wilcoxon's signed rank test for comparison of the SSBB-EPI and TSE sequences, with P = 0.05 considered the limit for significance. The SSBB-EPI sequence was improved by the following steps: 1) less frequency points than phase-encoding steps, 2) a b-factor of 20, and 3) a reversed polarity of the phase-encoding gradient. In patients, the mean overall image quality score for the optimized SSBB-EPI (3.5 (range: 1-4)) and TSE (3.6 (range: 3-4)), and the SNR of the liver on SSBB-EPI (mean +/- SD = 7.6 +/- 4.0) and TSE (8.9 +/- 4.6) were not significantly different (P > .05). Optimized SSBB-EPI with SENSE proved to be feasible in patients, and the overall image quality and SNR of the liver were comparable to those achieved with the standard respiratory-triggered T2-weighted TSE sequence. (c) 2005 Wiley-Liss, Inc.

  5. Acquired hypertrichosis lanuginosa

    Directory of Open Access Journals (Sweden)

    Kumar Pramod

    1993-01-01

    Full Text Available Acquired hypertirichosis lanuginose developed rapidly in a patient with no detectable malignancy. Soft, fine, downy hair growth was noticed on the face, ears, limbs and trunk. Bilaterally symmetrical vitiliginous macules were present on the ear and preauricular region. This case is reported because of its rarity, absence of any detectable malignancy and development of vitiligo, which to our knowledge has not been reported earlier.

  6. Statistical approach of measurement of signal to noise ratio in according to change pulse sequence on brain MRI meningioma and cyst images

    International Nuclear Information System (INIS)

    Lee, Eul Kyu; Choi, Kwan Woo; Jeong, Hoi Woun; Jang, Seo Goo; Kim, Ki Won; Son, Soon Yong; Min, Jung Whan; Son, Jin Hyun

    2016-01-01

    The purpose of this study was to needed basis of measure MRI CAD development for signal to noise ratio (SNR) by pulse sequence analysis from region of interest (ROI) in brain magnetic resonance imaging (MRI) contrast. We examined images of brain MRI contrast enhancement of 117 patients, from January 2005 to December 2015 in a University-affiliated hospital, Seoul, Korea. Diagnosed as one of two brain diseases such as meningioma and cysts SNR for each patient's image of brain MRI were calculated by using Image J. Differences of SNR among two brain diseases were tested by SPSS Statistics21 ANOVA test for there was statistical significance (p < 0.05). We have analysis socio-demographical variables, SNR according to sequence disease, 95% confidence according to SNR of sequence and difference in a mean of SNR. Meningioma results, with the quality of distributions in the order of T1CE, T2 and T1, FLAIR. Cysts results, with the quality of distributions in the order of T2 and T1, T1CE and FLAIR. SNR of MRI sequences of the brain would be useful to classify disease. Therefore, this study will contribute to evaluate brain diseases, and be a fundamental to enhancing the accuracy of CAD development

  7. Statistical approach of measurement of signal to noise ratio in according to change pulse sequence on brain MRI meningioma and cyst images

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eul Kyu [Inje Paik University Hospital Jeo-dong, Seoul (Korea, Republic of); Choi, Kwan Woo [Asan Medical Center, Seoul (Korea, Republic of); Jeong, Hoi Woun [The Baekseok Culture University, Cheonan (Korea, Republic of); Jang, Seo Goo [The Soonchunhyang University, Asan (Korea, Republic of); Kim, Ki Won [Kyung Hee University Hospital at Gang-dong, Seoul (Korea, Republic of); Son, Soon Yong [The Wonkwang Health Science University, Iksan (Korea, Republic of); Min, Jung Whan; Son, Jin Hyun [The Shingu University, Sungnam (Korea, Republic of)

    2016-09-15

    The purpose of this study was to needed basis of measure MRI CAD development for signal to noise ratio (SNR) by pulse sequence analysis from region of interest (ROI) in brain magnetic resonance imaging (MRI) contrast. We examined images of brain MRI contrast enhancement of 117 patients, from January 2005 to December 2015 in a University-affiliated hospital, Seoul, Korea. Diagnosed as one of two brain diseases such as meningioma and cysts SNR for each patient's image of brain MRI were calculated by using Image J. Differences of SNR among two brain diseases were tested by SPSS Statistics21 ANOVA test for there was statistical significance (p < 0.05). We have analysis socio-demographical variables, SNR according to sequence disease, 95% confidence according to SNR of sequence and difference in a mean of SNR. Meningioma results, with the quality of distributions in the order of T1CE, T2 and T1, FLAIR. Cysts results, with the quality of distributions in the order of T2 and T1, T1CE and FLAIR. SNR of MRI sequences of the brain would be useful to classify disease. Therefore, this study will contribute to evaluate brain diseases, and be a fundamental to enhancing the accuracy of CAD development.

  8. Improved imaging of cochlear nerve hypoplasia using a 3-Tesla variable flip-angle turbo spin-echo sequence and a 7-cm surface coil.

    Science.gov (United States)

    Giesemann, Anja M; Raab, Peter; Lyutenski, Stefan; Dettmer, Sabine; Bültmann, Eva; Frömke, Cornelia; Lenarz, Thomas; Lanfermann, Heinrich; Goetz, Friedrich

    2014-03-01

    Magnetic resonance imaging of the temporal bone has an important role in decision making with regard to cochlea implantation, especially in children with cochlear nerve deficiency. The purpose of this study was to evaluate the usefulness of the combination of an advanced high-resolution T2-weighted sequence with a surface coil in a 3-Tesla magnetic resonance imaging scanner in cases of suspected cochlear nerve aplasia. Prospective study. Seven patients with cochlear nerve hypoplasia or aplasia were prospectively examined using a high-resolution three-dimensional variable flip-angle turbo spin-echo sequence using a surface coil, and the images were compared with the same sequence in standard resolution using a standard head coil. Three neuroradiologists evaluated the magnetic resonance images independently, rating the visibility of the nerves in diagnosing hypoplasia or aplasia. Eight ears in seven patients with hypoplasia or aplasia of the cochlear nerve were examined. The average age was 2.7 years (range, 9 months-5 years). Seven ears had accompanying malformations. The inter-rater reliability in diagnosing hypoplasia or aplasia was greater using the high-resolution three-dimensional variable flip-angle turbo spin-echo sequence (fixed-marginal kappa: 0.64) than with the same sequence in lower resolution (fixed-marginal kappa: 0.06). Examining cases of suspected cochlear nerve aplasia using the high-resolution three-dimensional variable flip-angle turbo spin-echo sequence in combination with a surface coil shows significant improvement over standard methods. © 2013 The American Laryngological, Rhinological and Otological Society, Inc.

  9. The use of phase sequence image sets to reconstruct the total volume occupied by a mobile lung tumor

    International Nuclear Information System (INIS)

    Gagne, Isabelle M.; Robinson, Don M.; Halperin, Ross; Roa, Wilson

    2005-01-01

    The use of phase sequence image (PSI) sets to reveal the total volume occupied by a mobile target is presented. Isocontrast composite clinical target volumes (CCTVs) may be constructed from PSI sets in order to reveal the total volume occupied by a mobile target during the course of its travel. The ability of the CCTV technique to properly account for target motion is demonstrated by comparison to contours of the true total volume occupied (TVO) for a number of experimental phantom geometries. Finally, using real patient data, the clinical utility of the CCTV technique to properly account for internal tumor motion while minimizing the volume of healthy lung tissue irradiated is assessed by comparison to the standard approach of applying safety margins. Results of the phantom study reveal that CCTV cross sections constructed at the 20% isocontrast level yield good agreement with the total cross sections (TXO) of mobile targets. These CCTVs conform well to the TVOs of the moving targets examined whereby the addition of small uniform margins ensures complete circumscription of the TVO with the inclusion of minimal amounts of surrounding external volumes. The CCTV technique is seen to be clearly superior to the common practice of the addition of safety margins to individual CTV contours in order to account for internal target motion. Margins required with the CCTV technique are eight to ten times smaller than those required with individual CTVs

  10. Imaging the Crust in the Northern Sector of the 2009 L'Aquila Seismic Sequence through Oil Exploration Data Interpretation

    Science.gov (United States)

    Grazia Ciaccio, Maria; Improta, Luigi; Patacca, Etta; Scandone, Paolo; Villani, Fabio

    2010-05-01

    The 2009 L'Aquila seismic sequence activated a complex, about 40 km long, NW-trending and SW-dipping normal fault system, consisting of three main faults arranged in right-lateral en-echelon geometry. While the northern sector of the epicentral area was extensively investigated by oil companies, only a few scattered, poor-quality commercial seismic profiles are available in the central and southern sector. In this study we interpret subsurface commercial data from the northern sector, which is the area where is located the source of the strong Mw5.4 aftershock occurred on the 9th April 2009. Our primary goals are: (1) to define a reliable framework of the upper crust structure, (2) to investigate how the intense aftershock activity, the bulk of which is clustered in the 5-10 km depth range, relates to the Quaternary extensional faults present in the area. The investigated area lies between the western termination of the W-E trending Gran Sasso thrust system to the south, the SW-NE trending Mt. Sibillini thrust front (Ancona-Anzio Line Auctt.) to the north and west, and by the NNW-SSE trending, SW-dipping Mt. Gorzano normal fault to the east. In this area only middle-upper Miocene deposits are exposed (Laga Flysch and underlying Cerrogna Marl), but commercial wells have revealed the presence of a Triassic-Miocene sedimentary succession identical to the well known Umbria-Marche stratigraphic sequence. We have analyzed several confidential seismic reflection profiles, mostly provided by ENI oil company. Seismic lines are tied to two public wells, 5766 m and 2541 m deep. Quality of the reflection imaging is highly variable. A few good quality stack sections contain interpretable signal down to 4.5-5.5 s TWT, corresponding to depths exceeding 10-12 km and thus allowing crustal imaging at seismogenic depths. Key-reflectors for the interpretation correspond to: (1) the top of the Miocene Cerrogna marls, (2) the top of the Upper Albian-Oligocene Scaglia Group, (3) the

  11. Acquired Duodenal Obstruction in Children

    Directory of Open Access Journals (Sweden)

    Jen-Hung Chien

    2008-10-01

    Full Text Available Traumatic intramural hematoma of the duodenum is a rare cause of acquired duodenal obstruction in children, and a high degree of suspicion is therefore required to make an early and accurate diagnosis. We report a 6-year-old boy whose epigastrium was impacted by the handlebar of his bicycle during a traffic accident. The boy then experienced epigastralgia. Six days later, progressive bilious vomiting suggestive of gastrointestinal obstruction was noted. Imaging studies revealed a large hematoma extending from the fourth portion of the duodenum to the jejunum. Conservative methods of treatment failed to manage his condition. He underwent laparoscopic surgery to evacuate the hematoma. We also report a case of duodenal obstruction in a previously healthy 2-year-old girl who presented for the first time with acute symptoms of proximal intestinal obstruction. Contrast examinations showed apparent barium retention over the stomach and proximal duodenum. She underwent surgery due to persistent obstruction, and a mushroom-like foreign body was detected embedded in the orifice of the windsock duodenal web. After duodenoduodenostomy and removal of the bezoar, she had a smooth recovery and tolerated feeding well. We conclude that blunt abdominal trauma and incomplete duodenal obstruction, such as that caused by duodenal web, should be considered as possible causes of acquired proximal gastrointestinal obstruction in previously healthy children, despite their rarity.

  12. Imaging 2015 Mw 7.8 Gorkha Earthquake and Its Aftershock Sequence Combining Multiple Calibrated Global Seismic Arrays

    Science.gov (United States)

    LI, B.; Ghosh, A.

    2016-12-01

    The 2015 Mw 7.8 Gorkha earthquake provides a good opportunity to study the tectonics and earthquake hazards in the Himalayas, one of the most seismically active plate boundaries. Details of the seismicity patterns and associated structures in the Himalayas are poorly understood mainly due to limited instrumentation. Here, we apply a back-projection method to study the mainshock rupture and the following aftershock sequence using four large aperture global seismic arrays. All the arrays show eastward rupture propagation of about 130 km and reveal similar evolution of seismic energy radiation, with strong high-frequency energy burst about 50 km north of Kathmandu. Each single array, however, is typically limited by large azimuthal gap, low resolution, and artifacts due to unmodeled velocity structures. Therefore, we use a self-consistent empirical calibration method to combine four different arrays to image the Gorkha event. It greatly improves the resolution, can better track rupture and reveal details that cannot be resolved by any individual array. In addition, we also use the same arrays at teleseismic distances and apply a back-projection technique to detect and locate the aftershocks immediately following the Gorkha earthquake. We detect about 2.5 times the aftershocks recorded by the Advance National Seismic System comprehensive earthquake catalog during the 19 days following the mainshock. The aftershocks detected by the arrays show an east-west trend in general, with majority of the aftershocks located at the eastern part of the rupture patch and surrounding the rupture zone of the largest Mw 7.3 aftershock. Overall spatiotemporal aftershock pattern agrees well with global catalog, with our catalog showing more details relative to the standard global catalog. The improved aftershock catalog enables us to better study the aftershock dynamics, stress evolution in this region. Moreover, rapid and better imaging of aftershock distribution may aid rapid response

  13. Optimizing the magnetization-prepared rapid gradient-echo (MP-RAGE sequence.

    Directory of Open Access Journals (Sweden)

    Jinghua Wang

    Full Text Available The three-dimension (3D magnetization-prepared rapid gradient-echo (MP-RAGE sequence is one of the most popular sequences for structural brain imaging in clinical and research settings. The sequence captures high tissue contrast and provides high spatial resolution with whole brain coverage in a short scan time. In this paper, we first computed the optimal k-space sampling by optimizing the contrast of simulated images acquired with the MP-RAGE sequence at 3.0 Tesla using computer simulations. Because the software of our scanner has only limited settings for k-space sampling, we then determined the optimal k-space sampling for settings that can be realized on our scanner. Subsequently we optimized several major imaging parameters to maximize normal brain tissue contrasts under the optimal k-space sampling. The optimal parameters are flip angle of 12°, effective inversion time within 900 to 1100 ms, and delay time of 0 ms. In vivo experiments showed that the quality of images acquired with our optimal protocol was significantly higher than that of images obtained using recommended protocols in prior publications. The optimization of k-spacing sampling and imaging parameters significantly improved the quality and detection sensitivity of brain images acquired with MP-RAGE.

  14. Comparing an accelerated 3D fast spin-echo sequence (CS-SPACE) for knee 3-T magnetic resonance imaging with traditional 3D fast spin-echo (SPACE) and routine 2D sequences

    Energy Technology Data Exchange (ETDEWEB)

    Altahawi, Faysal F.; Blount, Kevin J.; Omar, Imran M. [Northwestern University Feinberg School of Medicine, Department of Radiology, Chicago, IL (United States); Morley, Nicholas P. [Marshfield Clinic, Department of Radiology, Marshfield, WI (United States); Raithel, Esther [Siemens Healthcare GmbH, Erlangen (Germany)

    2017-01-15

    To compare a faster, new, high-resolution accelerated 3D-fast-spin-echo (3D-FSE) acquisition sequence (CS-SPACE) to traditional 2D and high-resolution 3D sequences for knee 3-T magnetic resonance imaging (MRI). Twenty patients received knee MRIs that included routine 2D (T1, PD ± FS, T2-FS; 0.5 x 0.5 x 3 mm{sup 3}; ∝10 min), traditional 3D FSE (SPACE-PD-FS; 0.5 x 0.5 x 0.5 mm{sup 3}; ∝7.5 min), and accelerated 3D-FSE prototype (CS-SPACE-PD-FS; 0.5 x 0.5 x 0.5 mm{sup 3}; ∝5 min) acquisitions on a 3-T MRI system (Siemens MAGNETOM Skyra). Three musculoskeletal radiologists (MSKRs) prospectively and independently reviewed the studies with graded surveys comparing image and diagnostic quality. Tissue-specific signal-to-noise ratios (SNR) and contrast-to-noise ratios (CNR) were also compared. MSKR-perceived diagnostic quality of cartilage was significantly higher for CS-SPACE than for SPACE and 2D sequences (p < 0.001). Assessment of diagnostic quality of menisci and synovial fluid was higher for CS-SPACE than for SPACE (p < 0.001). CS-SPACE was not significantly different from SPACE but had lower assessments than 2D sequences for evaluation of bones, ligaments, muscles, and fat (p ≤ 0.004). 3D sequences had higher spatial resolution, but lower overall assessed contrast (p < 0.001). Overall image quality from CS-SPACE was assessed as higher than SPACE (p = 0.007), but lower than 2D sequences (p < 0.001). Compared to SPACE, CS-SPACE had higher fluid SNR and CNR against all other tissues (all p < 0.001). The CS-SPACE prototype allows for faster isotropic acquisitions of knee MRIs over currently used protocols. High fluid-to-cartilage CNR and higher spatial resolution over routine 2D sequences may present a valuable role for CS-SPACE in the evaluation of cartilage and menisci. (orig.)

  15. Evaluation of MRI sequences for quantitative T1 brain mapping

    Science.gov (United States)

    Tsialios, P.; Thrippleton, M.; Glatz, A.; Pernet, C.

    2017-11-01

    T1 mapping constitutes a quantitative MRI technique finding significant application in brain imaging. It allows evaluation of contrast uptake, blood perfusion, volume, providing a more specific biomarker of disease progression compared to conventional T1-weighted images. While there are many techniques for T1-mapping there is a wide range of reported T1-values in tissues, raising the issue of protocols reproducibility and standardization. The gold standard for obtaining T1-maps is based on acquiring IR-SE sequence. Widely used alternative sequences are IR-SE-EPI, VFA (DESPOT), DESPOT-HIFI and MP2RAGE that speed up scanning and fitting procedures. A custom MRI phantom was used to assess the reproducibility and accuracy of the different methods. All scans were performed using a 3T Siemens Prisma scanner. The acquired data processed using two different codes. The main difference was observed for VFA (DESPOT) which grossly overestimated T1 relaxation time by 214 ms [126 270] compared to the IR-SE sequence. MP2RAGE and DESPOT-HIFI sequences gave slightly shorter time than IR-SE (~20 to 30ms) and can be considered as alternative and time-efficient methods for acquiring accurate T1 maps of the human brain, while IR-SE-EPI gave identical result, at a cost of a lower image quality.

  16. The acquired hyperostosis syndrome

    International Nuclear Information System (INIS)

    Dihlmann, W.; Hering, L.; Bargon, G.W.

    1988-01-01

    Sterno-costo-clavicular hyperostosis (SCCH) is the most common manifestation of a syndrome, consisting of increased bone metabolism, mostly new bone formation and heterotopic ossification of fibrous tissue, which we have characterised as the acquired hyperostosis syndrome. In part I we discuss the terminology, radiological appearances, scintigraphy, clinical and laboratory findings, bacteriology, histology, nosology, complications, treatment and differential diagnosis of SCCH. Chronic recurrent multifocal osteomyelitis (CRMO) is regarded as a phaenotype of SCCH, depending on the age. CRMO occurs in children, adolescents and young adults, SCCH predominantly in middleaged and elderly adults. (orig.) [de

  17. Acquired epidermolysis bullosa

    Directory of Open Access Journals (Sweden)

    Maricel Sucar Batista

    2015-12-01

    Full Text Available Epidermolysis bullosa is a group of diseases or skin disorders genetically transmitted and it is characterized by the appearance of bullae, ulcers and skin wounds. It usually appears at birth or in the first months of life. This is a case of a 72-year-old female patient who comes to the dermatology department with skin lesions of 6 months of evolution. A skin biopsy was performed, taking a sample for direct and indirect immunofluorescence. Acquired epidermolysis bullosa of unknown etiology was diagnosed. Treatment was started with low-dose colchicine to increase it later, according to the patient’s tolerance and disease progression.

  18. Three-dimensional isotropic fat-suppressed proton density-weighted MRI at 3 tesla using a T/R-coil can replace multiple plane two-dimensional sequences in knee imaging

    Energy Technology Data Exchange (ETDEWEB)

    Homsi, R.; Luetkens, J.A. [Bonn Univ. (Germany). Dept. of Radiology; Gieseke, J. [Philips Healthcare, Hamburg (Germany); and others

    2016-10-15

    To evaluate whether a 3D proton density-weighted fat-suppressed sequence (PDwFS) of the knee is able to replace multiplanar 2D-PDwFS. 52 patients (26 men, mean age: 41.9±14.5 years) underwent magnetic resonance imaging (MRI) of the knee at 3.0 Tesla using a T/R-coil. The imaging protocol included 3 planes of 2D-PDwFS (acquisition time (AT): 6:40 min; voxel sizes: 0.40-0.63 x 0.44-0.89 x 3 mm{sup 3}) and a 3D-PDwFS (AT: 6:31 min; voxel size: 0.63 x 0.68 x 0.63 mm{sup 3}). Homogeneity of fat suppression (HFS), artifacts, and image sharpness (IS) were evaluated on a 5-point scale (5[excellent] - 1[non-diagnostic]). The sum served as a measure for the overall image quality (OIQ). Contrast ratios (CR) compared to popliteal muscle were calculated for the meniscus (MEN), anterior (ACL) and posterior cruciate ligaments (PCL). In 13 patients who underwent arthroscopic knee surgery, two radiologists evaluated the presence of meniscal, ligamental and cartilage lesions to estimate the sensitivity and specificity of lesion detection. The CR was higher in the ACL, PCL and MEN in 3D- PDwFS compared to 2D-PDwFS (p<0.01 for ACL and PCL; p=0.07 for MEN). Compared to 2D images, the OIQ was rated higher in 3D-PDwFS images (p<0.01) due to fewer artifacts and HFS despite the lower IS (p<0.01). The sensitivity and specificity of lesion detection in 3D- and 2D-PDwFS were similar. Compared to standard multiplanar 2D-PDwFS knee imaging, isotropic high spatial resolution 3D-PDwFS of the knee at 3.0T can be acquired with high image quality in a reasonable scan time. Multiplanar reformations in arbitrary planes may serve as an additional benefit of 3D-PDwFS.

  19. High-resolution T2-weighted MR imaging of the inner ear using a long echo-train-length 3D fast spin-echo sequence

    International Nuclear Information System (INIS)

    Naganawa, S.; Yamakawa, K.; Fukatsu, H.; Ishigaki, T.; Nakashima, T.; Sugimoto, H.; Aoki, I.; Miyazaki, M.; Takai, H.

    1996-01-01

    The purpose of this study was to assess the value of a long echo-train-length 3D fast spin-echo (3D-FSE) sequence in visualizing the inner ear structures. Ten normal ears and 50 patient ears were imaged on a 1.5T MR unit using a head coil. Axial high-resolution T2-weighted images of the inner ear and the internal auditory canal (IAC) were obtained in 15 min. In normal ears the reliability of the visualization for the inner ear structures was evaluated on original images and the targeted maximum intensity projection (MIP) images of the labyrinth. In ten normal ears, 3D surface display (3D) images were also created and compared with MIP images. On the original images the cochlear aqueduct, the vessels in the vicinity of the IAC, and more than three branches of the cranial nerves were visualized in the IAC in all the ears. The visibility of the endolympathic duct was 80%. On the MIP images the visibility of the three semicircular canals, anterior and posterior ampulla, and of more than two turns of the cochlea was 100%. The MIP images and 3D images were almost comparable. The visibility of the endolymphatic duct was 80% in normal ears and 0% in the affected ears of the patients with Meniere's disease (p<0.001). In one patient ear a small intracanalicular tumor was depicted clearly. In conclusion, the long echo train length T2-weighted 3D-FSE sequence enables the detailed visualization of the tiny structures of the inner ear and the IAC within a clinically acceptable scan time. Furthermore, obtaining a high contrast between the soft/bony tissue and the cerebrospinal/endolymph/perilymph fluid would be of significant value in the diagnosis of the pathologic conditions around the labyrinth and the IAC. (orig.)

  20. Readout-segmented echo-planar imaging improves the image quality of diffusion-weighted MR imaging in rectal cancer: Comparison with single-shot echo-planar diffusion-weighted sequences

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Chun-chao; Liu, Xi; Peng, Wan-lin; Li, Lei; Zhang, Jin-ge [Department of Radiology, West China Hospital, Sichuan University, 37# Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Meng, Wen-jian; Deng, Xiang-bing [Department of Gastrointestinal Surgery, West China Hospital, Sichuan University, 37# Guo Xue Xiang, Chengdu, Sichuan 610041 (China); Zuo, Pan-li [Siemens Healthcare, MR Collaborations NE Asia, 100010, Beijing (China); Li, Zhen-lin, E-mail: lzlcd01@126.com [Department of Radiology, West China Hospital, Sichuan University, 37# Guo Xue Xiang, Chengdu, Sichuan 610041 (China)

    2016-10-15

    Purpose: To determine whether readout-segme